EPA-600/2-89-062
November 1989
AEROSOL INDUSTRY SUCCESS
IN REDUCING CFC PROPELLANT USAGE
Prepared by:
Thomas P. Nelson
Sharon L. Wevill
Radian Corporation
Austin, TX 78720-1088
EPA Contract No. 68-02-4286
Work Assignment No. 64
EPA Project Officer
N. Dean Smith
Air and Energy Engineering Research Laboratory
Office of Environmental Engineering and Technology Demonstration
Research Triangle Park, NC 27711
Prepared', for:
U.S. Environmental Protection Agency
Office of Research and Development
Washington, DC 20460
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1, REPORT NO. 2.
EPA-600/2-89-062
3, RECIPIENT'S ACCESSION NO™
»9® I 4344?yAS
4. TITLE AND SUBTITLE
Aerosol Industry Success in Reducing CFC Propellant
Usage
5. REPORT DATE ~
November 1989
6. PERFORMING ORGANIZATION CODE
7. AUTHORSS)
Thomas P. Nelson and Sharon L. Wevill
8. PERFORMING ORGANIZATION REPORT NO.
9, PERFORMING ORGANIZATION NAME AND ADDRESS
Radian Corporation
P. O. Box 201088
Austin, Texas 78720
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-4286, Task 64
12.SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air and Energy Engineering Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Task Final; 1-9/89
14. SPONSORING AGENCY CODE
EPA/600/13
is. supplementary notes aeERL project officer is N. Dean Smith, Mail Drop 62B, 919/541-
2708N3
is. ABSTRACT^^e two_part report discusses the reduction of chlorofluorocarbon (CFC)
propellant usage. Part I discusses the U. S. aerosol industry's experience in conver-
ting from CFC propellants to alternative aerosol formulations. Detailed examples
of non-CFC formulations are provided for 28 categories of aerosol products. Hydro-
carbon propellants, which cost less than CFCs, are most often selected as the pro-
pellants of choice unless special properties (e. g., increased solvency or reduced
flammability) are needed. Dimethyl ether is the next most preferred CFC alternative,
although it is flammable and a strong solvent. Carbon dioxide, nitrous oxide, and
nitrogen are inexpensive, and widely available, but have been underused as aerosol
propellants. Special equipment is often needed to add them to the aerosol, containers..
A variety of alternative aerosol packaging forms are discussed in Part II, with spe-
cial focus on those most like regular aerosols in characteristics. Advantages and
drawbacks of several types of alternative dispensing devices are discussed in detail
and examples are provided of the types of consumer products which have success-
fully utilized these alternatives.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATl Field/Gioup
Pollution
Aerosols
Chlor©hydrocarbons
Fluorohydrocarbons
Packaging
Charging
Dispensers
Pollution Control
Stationary Sources
Chlorofluorocarbons
13 B
07D
07 C
13 D
14 G
131
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report) ^
Unclassified /,_
21. NO. OF PAGES
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
-------
The two-part report discusses the reduction of chlorofluorocarbon (CFC)
propellent usage. Part I discusses the U.S. aerosol industry's experience in
converting from GFG propellants to alternative aerosol formulations. Detailed
examples of non-CFC formulations are provided for 28 categories of aerosol
products. Hydrocarbon propellants, which cost less than CFCs, are most often
selected as the propel1 ants of choice unless special properties (e.g., increased
solvency or reduced flamraability) are needed. Dimethyl ether is the next most
preferred CFG alternative, although it is flammable and a strong solvent. Carbon
dioxide, nitrous oxide, and nitrogen are inexpensive and widely available, but
have been underused as aerosol propellants. Special equipment is often needed
to add them to the aerosol containers. A variety of alternative aerosol
packaging forms are discussed in Part II, with special focus on those most like
regular aerosols in characteristics. Advantages and drawbacks of several types
of alternative dispensing devices are discussed in detail and examples are
provided of the types of consumer products which have successfully utilized these
alternatives.
-------
CONTENTS
Abstract ii
Figures : iv
Tables • v
Part I - Alternative Aerosol Formulations ' -. 1
1. Introduction ...... 2
2. Formulation Guidelines . . . , /.¦ . . * ¦. 13
General Considerations.. .. . * 13
3. Example Non-CfC Alternative Formulations. . . ... .....: 24
Cosmetics, Toiletries, and Personal Care Products 24
Household Products ;¦ 81
Pesticide Aerosol Products . ." 120
Pharmaceutical Products 123
Industrial Aerosol Products 127
Part II - Alternative Aerosol Dispensing Systems • 133
1. Introduction 134
2. Description of Aerosol Packaging Alternatives 140
Bag - In-Can Types 140
Piston Cans 168
Independent Bag-In-Can Systems 174
Pump Sprays - Aspirator Types 180
Pump Sprays - Standard Types 182
Dispensing Closures . ... 193
Pressurizing Dispensers 195
Miscellaneous Aerosol Alternatives 210
3. Summary 216
Appendix A Metric (SI) Conversion Factors 219
iii
-------
FIGURES
Figure 'Page
1 Foam Syringe 59
2 The Sepro Can . 141
3- Ordinary Aerosol Dispenser with Toothpaste 143
4 Slow-Speed Grow Pak Packaging 178
5 The "Flit Gun" Aspirator-Type Insecticide Space Sprayer 181
6 Cross-Section of Finger-Action Seaquist Valve, Set in 22-415
Closure. 184
7 Comparison of Risdon (Dispensing Systems Division) Finger-Pump
20mm TNT Pump and SL-40 Micro-Mist vs. 20mm Aerosol Valve.,.. 186
'8 Various Dispensing Closures-Made by the Seaquist Closures
Division 194
9 Twist-N-Mist II.. 197
10 Suction and Pressurization Stages of the Twist-N-Mist II
Dispenser, 198
iv
-------
TABLES
Table ^ Paj^e
1 Emissions and Ozone Depletion Potentials of Aerosol
Propeilants and Related Compounds t....'- 1 4'
2 Physical Properties of Non-CFC Aerosol Propeilants ¦; . » 7
3 Product Applications of Carbon Dioxide, Nitrous Oxide, and
Nitrogen. 8-
4 Exempted, Excluded, or Nonregulated CFG Aerosol Products (U.S.)--. 12
5 Dispersancy Characteristics of Various Propeilants.,... 14
6 Hair Spray Formulations Using Both Hydrocarbon and Dimethyl Ether
Propeilants (Regular Hold). 27
7 Hair Conditioner Spray Formulations 29
8 Mousse Hair Set and Conditioning Product Formulations 33
9 Ingredient Listings of Other Mousse Hair Sets and Conditioners,... 39
10 Specialty Mousse Formulations 45
11 Sunscreen Mousse Formulations 50
12 Baby Care Mousse, Formulations 55
13 Vaginal Contraceptive Mousse 57
14 Mousse for Mastitis Treatment 58
15 Shave C reams>61
16 Comparison of Antiperspirant Efficiencies 67
17 Aerosol Antiperspirant 68
18 Personal Deodorants 76
19 Cologne Formulations 79
20 Household Aerosol Products Sold in the U.S. During 1988 82
21 Household Aerosol Product Delivery Modes 84
22 Window Cleaner Formulations 88
23 Anti-Fogging or Anti-Static Glass Cleaner Formulations 89
24 Spray Starch Formulations. . 91
25 Fabric Finish Formulations 95
v
-------
(Continued)
Table Page
26 Hard Surface Gleaner Formulations 97
27 Oven Cleaner Formulations 99
28 Pre-Laundry Cleaner Formulations 101
29 Rug and Carpet Cleaner Product Formulation 103
30 Air Freshener Formulations 106
31 Disinfectant/Deodorant Formulations 109
32 Disinfectant Cleaner Formulations Ill
33 Various Aerosol Paint Formulations 113
34 Furniture Polish Formulations 116
35 Wood Panel Polish Formulations 118
36 Windshield De-icer Formulations..., 119
37 Total Release Insect Fogger Formulations 122
38 Insect Repellent Formulations 124
39 Beta-Adrenergic Bronchodilator Formula 126
40 Metered-Dose Inhalant Drug Formulations 128
41 Rotary Tablet Machine Die Lubricant Formulations 130
42 Gasket Adhesive Formulation 131
43 Product Mix for Sepro Can Dispensing 146
44 CTFA Label Ingredient Listings for the Three Gel-Type Shave
Creams 147
45 Prices for Terco, Inc. Gasser-Pluggers (1989) 159
46 Aerosol and Finger-Pump Hair Sprays: Comparison of Particle Size
Distributions 188
47 Typical Current Customers and Products of the Exxel System 202
48 Cost of Exxel System Packaging and Filling Services 203
49 Minimum Dimensions of Outer Containers for Exxel Units 205
50 Specifications—Using Four Nozzles--For the Werdi 'R' Actuator.... 211
51 Two Stick Antiperspirant Formulas 213
52 Production Units of Underarm Products (U.S.) 215
vi
-------
Part I - ALTERNATIVE AEROSOL FORMULATIONS
V
1
-------
SECTION 1
INTRODUCTION
Therg i.s an urgent need to reformulate ssrosol products into compositions
that no longer contain chlorofluorocarbons (CxClyFz) . As early as 1973,
scientists recognized that these compounds had very long atmospheric lives and
could ultimately penetrate the stratospheric ozone layer at altitudes of
between about 14 to 27 km. Once in the stratosphere, GFCs are bombarded with
high-energy radiation from the sun, splitting off a chlorine atom that reacts
with thousands of ozone molecules and reduces them to ordinary oxygen.
Although the ozone is reformed by natural processes over time, the overall
effect is of ozone depletion.
During September 1987, a meeting held-in Montreal, Canada was attended by
representatives of many nations. A treaty known as the Montreal Protocol was
developed calling for the orderly reduction of chlorofluofocarbon (CFG)
production, roughly according to the following schedule:
By July 1, 1989 Reduction to the 1986 average production level [15-
25% actual reduction in the U.S. because of the
growth in CFC use since 1986; Ozone Depletion
Potential (ODP) basis.]
By July 1, 1993 Reduction to 80% of the 1986 average level, ODP
basis.
By July 1, 1998 Reduction to 50% of the 1986 average level, ODP
Basis.
2
-------
As of October 1989, the treaty had been ratified by 43 nations plus the
European Community (EG) as a bloc, which together produce approximately 90% of'
the world tonnage of CFCs.
The results of stratospheric studies made after the Montreal Protocol now
strongly suggest that the reduction plan is insufficient to prevent a further
depletion of ozone.
Another problem has surfaced, however. As CFCs are phased out, they will
be replaced by such chemicals as HCFC-22, 1.1,1-trichloroethane (methyl
chloroform) and similar substances, many of which can also deplete
stratospheric ozone. Table 1 provides comparative figures.
In 1985, HCFC-22 was responsible for only 0,4% of ozone removal, while
1,1,1-trichloroethane caused about 5.1% ozone removal and CFC-12 was
responsible for about 40,1% of.the total ozone removal caused by the compounds
listed in Table 1. Except for the hydrocarbons and nitrogen, all the
compounds in Table 1 are anthropogenically produced.
Such compounds as HCFC-123, HCFC-124, HFC-134a, and HCFG-141b are ¦
currently undergoing extensive toxicological testing that is expected to
continue until about 1992, HCFC-123 currently has an Acceptable Exposure
Limit (AEL), or- TLV, of 100 ppm, but this may be changed to somewhere in the
50 to 100 ppra range as further results are developed. Similarly, HCFG-141b
may get an AEL of 100 to'-300 ppm. Results of the Ames Salmonella Test for
HCFG-22, HCFC-141b, and- HCFC-1*42b, show positive mutagenic results 5 for all the
compounds, but' extensive animal¦testing has clouded the meaning of the Ames
results. , • ¦ '¦ £ "
3
-------
TABLE 1. EMISSIONS AND OZONE DEPLETION POTENTIALS OF AEROSOL
PROPELLANTS AND RELATED COMPOUNDS
Compound
Structure
1985 Eiissions
(k tons/year) •
Ozone Depletion Potential
(GDP) (CFC-11 = 1)'
CFC-11
CC1,F
281
1.00
CFC-12
cci5F,
307
1.0
CFC-113
CCIjF-CCIFj
136
0,8
CFC-114
CC1F-CC1F;
(low)
0.8
crc-115
CC1F,-CFi
(very low)
0.4 (0,15)b
HCFC-22
. CHCIFj
72
0.05
1CFC-123
CHClj-CF,
o •
0.02
HCFC-132b
CHjCI-CCIF;
0
0.05
BCFC-124
C3C1F-CF,
0
0.02 •
HFC-134a
chj-cf3
0 .
0
HFC-125
CHFj-CP,
0
0
ECFC-141b
CH3-CC12F
0
0.10
SCFC-142b
CHj-CCIF,
(low)
0.06
HFC-152a
CE,-CiF?
0
0
Ealon 1211
CBrClF2
3
2.1
Halon 1301
CBrFj ,
3
10.0
Halon 2402
CBrFj-CBrF?
(very low)
5.6
Carbon Tetrachloride
CC14
66
1.2
1,1,1-Triehloroethane
CH,-CC1}
474 ¦ _ ¦- "
. 0.10 (0.15)"
Hydrocarbons
CtEj, etc.
(very large) ..
0
CO,, 1,0 S %
CQs, NjO,
¦ .(very large) -•
/Of
Diaethyl ether
CH-rO-GE,
¦ ' , . 42
; " _ o.
UHEP Data of 18-OCM988.
"Isaksen, et al (1988),
%0 can destroy stratospheric ozone but its ODP is undefined.
4
-------
Many of the future alternative compounds are nonflammable, while others
aire f 1 aminab 1 e. HCFC™123 is no nf 1 amiTiab 1 e, hut a mxxtute of thx s gas and 3.3^
isobutane is marginally flammable. HCFC-141b has a flammable range of 6.4 to
15.1%, while HCFC-142b's flammable range is 6,7 to 14.9%. HFC-134a, which is
being groomed as a replacement for most uses of CFC-12, is nonflammable.
HCFC-22 is the only nonflammable (1), commercially available CFC alternative
that the industry will have until about 1993 or 1994, when some or all of the
second generation CFC alternatives should come onto the market. It is only
marginally nonflammable; the addition of 6% isobutane, or 8.6% ethanol to
HCFC-22 will produce mixtures of borderline flammability.
'The worldwide aerosol business is highly diversified. In 1989, the U.S.
will produce about 3 billion units (95% non-CFC aerosols), or 35% of the world
total of about 8.6 billion units. Western Europe will produce about 39%,
Japan 5%, Brazil 21, and Mexico 0.5%. Per capita usage is 11 units per person
in the U.S.: the typical home contains 46 aerosol products, averaging 206 g
per unit. Since the purchase of aerosols is often discretionary (they are not
generally considered to be utility products) the per capita usage in different
countries is a reflection of both availability and of the relative standard of
living. The more hours a person must work to purchase an aerosol, the fewer
will be purchased.
Apart from the usual competitive pressures, there is a strong motivation
to reduce the costs of aerosol products in order to increase sales. In the
U.S., hydrocarbon propellants cost less than 20% of the rapidly escalating
costs of CFCs. They are therefore the propellants of choice unless special
properties are required, such as better solvent action or reduced
flammability. Approximately 81% of U.S. aerosols are pressurized with
propane, n-butane, isobutane, or their blends. Another 7% use carbon dioxide,
and the remaining 12% use nitrous oxide, CFCs, dimethyl ether, nitrogen, HFC-
152a and HCFCs, in approximately that order. The few CFC aerosols remaining
after the general ban on these products was imposed during 1978 are those
permitted by exclusion, exemption, or those that are not regulated.
5
-------
c
Hydrocarbon propellants are already in wide use throughout the world.
Examples are as follows: United Kingdom, a market share of 30%; West Germany,
80%; Brazil, 88%; Mexico, 92%; and Canada, 78%, The next preferred CFC
alternative is dimethyl ether (DME, or dimethyl oxide), DME alternatives are
about 10% more costly than the hydrocarbon alternatives in Western Europe,
100% more expensive in the U.S., and even more costly, or unavailable, in
other parts of the world. The major producers are Western Europe, with a
capacity of 60,000 tons, Japan, the U.S., Canada, and Australia. Dimethyl
ether is flammable. It is also a very strong solvent, sometimes causing
gasket failures in equipment, aerosol corrosion, valve seal leakage, and
excessive swelling of some elastomers. It is highly water soluble, and can be
used, as a way of incorporating water into solution in selected aerosol
products, such as hair sprays and personal deodorants. Table 2 compares the
physical properties of the non-CFC aerosol propellants.
Although carbon dioxide, nitrous oxide, and nitrogen are widely available
throughout the world, they have either been ignored or little used as aerosol
propellants. These gases are inexpensive, but special equipment is often
required to add them to aerosol containers. The simplest of these is the
gasser-shaker, of either in-line or rotary construction, which is shaken at a ,
preset frequency and amplitude for a fixed period of time. It is connected
through the valve to a supply of gas regulated to a pressure of approximately
142 to 178 psig (10.0 to 12.5 bars). Valve designs are available that will
facilitate gas flow into the can, even with the button attached. Since the
quantity of gas added will be in the range of 3 to 28 g, depending on can size
and content, the weight increase of the dispenser is used as a basis for
machine adjustments. Table 3 shows the potential uses of these propellants
for several representative products,
HCFC-22 is widely used throughout much of the world as a specialty
refrigerant and freezant. Despite its nonflammability (1) and relatively low
price (five times more costly than hydrocarbons, in the U.S.), it is not much
used. It is limited by its high pressure, which makes it necessary to use 40%
6
-------
TABLE 2. PHYSICAL PROPERTIES OF NON-CFC AEROSOL PROPELLANTS
Product
Formula
Boiling Paint
Vapor Pressure
CC) 21 'C
(bar)
55*C
Density at
21* (g/mL)
Flammable
Range v. X
nbutane'
-2
1.20
4.79
0.580
1.8 - a.6
isobutane
i,C4H10
-11
2.17
7.02
0.559
1.8 - 8.5
Propane
c3h8
-42
7.60
18.17
0.503
2.2 - 9.5
Dimethyl Ethsr
(CH3)20
-25
4.43
12.40
0.6S1
3.3 - 18.0
KCFC-22
CHCIFj
-41
8.52
20.92
1.208
0
ECFC-142b
ch3-ccif2
-10
2.04
6. 87
1.123
6.7 - 14.9
HFC-152a
CH3-CH?2
-25
4.42
12.36
0.911
3.9 - 16.9
Carbon Dioxide
cg2
-78
50.45
N/A
0.721
0
Nitrous Oxide
n2g
-88
52.47
N/A
0.718
3
Nitrogen
*2
-155
N/A
N/A
N/A
0
FUIUHE
FHOPELLANTS
HCFC-123
CHClj-CFj
ze
-0.2
1.7
1.470
0
HCFC-12A
chcif-cf3
-11
3.22
8.8
1,368
0
HFC-125
chf2-cf3
-95
N/A
N/A
K/A
0
HFC-134a
ch2f-cf3
-32
5,47
14.3
1.203
0
HCFC-14 lb
ch3-cci2f
33
-0.3
1.2
1.231
6.4 - 15.1
N/A = Hon Applicable, above Critical Temperature.
7
-------
TABLE 3. PRODUCT APPLICATIONS OF CARBON DIOXIDE, NITROUS OXIDE, AND NITROGEN
Carbon Dioxide
Hydroalcoholic disinfectant/deodorant sprays,
Bug killers:
Ant and roach killers
Wasp and hornet killers
Lubricants.
Anti-statics, soil repellants, and wrinkle removers - for
textiles.
Nitrous Oxide
Whipped creams.
Heavy-texture specialty foams,
Windshield and car lock de-icer sprays.
Furniture polish.
Nitrogen
Sterile saline solutions for rinsing contact lenses.
Long-range, stream-type wasp and hornet killers.
Injector-type engine cleaners.
Over-pressur'ant for selected meter-sprayed vitamins and drugs.
-------
or less in formulas and to include suppressive solvents or other propellants
to keep the aerosol pressure from being excessive. An interesting blend of
HCFC-22/HCFC-142b (40:60) is nonflammable and has a pressure of 63 psig at
70°F (4,43 bar at 21°C), It has been commercialized for perfumes and
colognes. HCFC-22 is a good solvent. At less than 28% propellant, its
ethanoT solutions are lower in pressure than those of CFC-12 and ethanol.
HCFC-142b is used in a few applications in the U.S. and is presently
unavailable elsewhere. It is now made by only one supplier, although a second
supply source is being developed. As the methyl homolog of HCFC-22, it has
many properties in common with the parent compound, except the high pressure.
It is more than 12'times as costly as hydrocarbon propellants in the U.S.,
which has restricted its aerosol applications.
HFC-152a is close to an ideal propellant, except that it is flammable.
It is less flammable than hydrocarbon gases, however, and it has typically
been used with 70% A-46 (20 mol % propane and 80 mol % isobutane) to produce a
propellant for shave creams, depilatories, and mousse products whose foam
surface will not momentarily flash if a lighted match is touched to it. The
composition is as follows:
60.9% Isobutane
9.1% Propane
30.0% HFC-152a
Since the pressure of the aerosol is about 154 psig at 130°F (11,0 bar at
55°C), according to the partial pressure of remaining air, an extra-strength
can Is needed,
HFC-152a is noted for Its exceptionally low odor and good solvency. It
is used to make less flammable colognes and perfumes, especially for those
essential oils that might eventually precipitate high-molecular weight resins,
fonds, or substantives in the usual ethanol/hydrocarbon (or pure hydrocarbon)
systems. Finally, it can be used with many surfactant systems, to partly
destabilize aerosol foams, permitting them to be more readily rubbed out on
9
-------
surfaces and not resist liquefaction, A typical product that uses this
property is baby oil mousse, which contains 20 to 30% mineral oil.
In the U.S.., since HFC -lb2a is approximately eight times the cost of
hydrocarbon propellants,1 the amounts used in' formulas are generally in the 2
to 1Q% range. It is available in the U.S. and Western Europe, and suppliers
claim that distribution systems will be set up to greatly increase world
access to this propellant and to HCFC-142b,
The future "CFG alternative/' propellants identified in Table 2 are
presently undergoing acute, sub-chronic, and chronic (lifetime) toxicological
testing. To date, the results have shown some variation in relative toxicity,
but indications are that all five compounds will probably be approved for
commercial use. The official toxicological reports will be issued in 1992 and
1993, but plans are now in motion to build production facilities well before
that time.
In the U.S.,.DuPont has announced that an existing commercial plant is
being converted to produce HCFG-141b and HCFC-142b in 1989. A new plant has
been approved to produce large quantities of HFC-134a by 1990, Large
quantities of HCFC-123 are already available as a co-product from an existing
DuFont facility. And during 1988 DuFont was issued a U.S. Patent on new
technology aimed at coproducing HCFC-123 and HCFC-124 in a single process. No
schedules for HCFC-124 production have been published.
Other CFC suppliers in the U.S., Western Europe, Japan, and other parts
of the world are also studying their options for phasing out CFCs and
commercializing various alternatives. The major alternative will probably be
HFC-134a, since it will be used to replace CFC-12 in refrigeration, freezant,
and air conditioning systems.
An accelerated CFC phase-down program, which goes beyond the Montreal
Protocol and is now supported by numerous countries, is based on rapid
commercialization and application of the HCFC and HFC alternatives. The
science centers around minimizing further increases in, the1 chlorine content of
the stratospheric ozone layer.
10
-------
Table 4 lists the aerosol products currently exempted or excluded from
the general regulatory bans in the U.S. on CFCs for aerosol uses. They serve
life-saving or other medical purposes, or are considered "essential for other
reasons."
A few of these products have been discontinued, such as the drain openers
and small-size tobacco barn sprays. The largest users of CFCs are the mold
release agents, lubricants, and meter-spray inhalant drug products, except for
CFC-12 and CFG-114 small refrigerant recharge units, which many people do not
consider to be true aerosol products.
When considering propellants or propellant/solvent combinations that may
be used for reformulating CFC aerosols, a large number of attributes must be
evaluated. Flammability, toxicology, solvency, cost, availability, solvate
formation, solvolytic stability, dispersancy, pressure, and compatibility are
some of the more essential characteristics. In the late 1980s, a growing
intolerance developed towards propellants and other chemicals that have even
slight effects on the stratospheric and tropospheric ecosystems, that have
greater perceived toxicity than alternatives, or do not degrade in landfills.
11
-------
TABLE 4. EXEMPTED, EXCLUDED, OR NONREGULATED CFC AEROSOL PRODUCTS (U.S.)
Mold release agents -- for molds making rubber and plastic items
Lubricants for use on electric or electronic equipment
Lubricants for rotary pill and tablet making presses
Solvent dusters, flushers, degreasers arid coatings for electric or electronic
equipment _ 'v-
Meter-spray inhalant drugs: •• , , '
a. Adrenergic bronchodilators , ...
b. Cortico steroids , *. ' t
c. Vaso-constrictors - ergotamine tartrate type
Contraceptive vaginal foams - for human use • •
Mercaptan (as ethyl thiol) mine warning devices ' ;
Intruder audio-alarm system canisters - for house and car uses
Flying insect sprays: ' , .
a. For commercial food-handling areas ,
b. For commercial (international) aircraft - cabin sprays '
c. For tobacco barns * . "
d. For military uses
Military aircraft operational and maintenance uses
Diamond grit abrasive uses
For' uses relating to national military preparedness
CFC-115 as a puffing (foaming) agent in certain food aerosols
Automobile tire inflators
Polyurethane foam aerosols
Chewing gum removers .
Drain openers
Medical chillers-- for localized operations
Medical solvents - as a spray bandage remover
Dusters for non electric or electronic uses - for phonograph records and
computer tapes
Cleaners for microscope slides and related objects
Foam, whip, or mousse products in general
Small refill units for refrigeration or air-conditioning systems
All other 100% CFG product applications
12
-------
SECTION 2
FORMULATION GUIDELINES
GENERAL CONSIDERATIONS
Dispersancy, one major attribute of aerosol propellants, is the
efficiency with which a propellant can produce a fine spray or an acceptable
foam. This is illustrated in Table 5.
The dispersancy of blends can be readily calculated. For example,
Propellant A-46 (20 mol% propane and 80 mol% isobutane) has a dispersancy of
[549 X .2 + 415 X .8] - 442 mL/g at 21.1°C.
A shave cream or mousse, made using either 8% CFC-12/114, 4% A-46, or 2%
nitrous oxide will all show the same properties of foam density and overrun.
(However, the nitrous oxide formula will have a very high pressure, which can
be expected to decrease significantly with use.)
In the years before the CFC aerosol ban of 1978 in the U.S., hair sprays
were commonly formulated with 45X CFC-12/11 (55:45), or 40X Propellant A (10%
Isobutane, 45% CFC-12, and 45% CFC-11). They are now formulated with 20 to
26% isobutane, sometimes with a small amount or propane added. These examples
show the importance of dispersive effect to propellant volume.
The dispersive effect is not linear but is modified by vapor-pressure,
solubility factors, and even by the pressure itself. It normally can be used
as a general guideline to determine equivalencies when changing from one
propellant choice to another.
13
-------
TABLE 5. DISPERSANCY CHARACTERISTICS OF VARIOUS PROPELLENTS
(In order of Vapor Volume in mL/g)
Propellant Vapor Volume (mL/g 21.1°C) Vapor Volume (mL/mL 21.1"C)
Nitrogen
862
N/A
Carbon Dioxide
549
N/A
Nitrous Oxide
549
N/A
Propane
549
280
Dimethyl Ether
523
345
isobutane
415
234
nbutane
415
239
HFC-152a
365
333
HCFC-22
279
337
CFC-115
256
(not available)
HCFC-142b
240
269
HFC-134a
236
283
HCFC-141b
206
253
CFC-12
200
265
CFC-125
198
227
CFC-11
176
261
HCFC-124
176
242
HCFC-123
158
232
CFC-114
141
207
FC-C318
119
179
Note: These propellants boil at <21.2"C (Range: 23° to 338C.)
N/A = Not Applicable
14
-------
The aerosol formulator will also have to determine such things as company
policy, availability of equipment, and the safety features of the workplace.
Nonflammable propellants (apart from CFCs) consist of nitrogen, nitrous
oxide, carbon dioxide, HCFC-22, and a few blends of other propellants with
HCFC-22. Future nonflammable propellants will consist of HCFC-123, HCFC-124,
HCFC-125, and HFC-134a. Of these, HFC-134a may become available most quickly
worldwide. The cost of HCFC and HFC propellants is expected to be about
twenty times that'of purified hydrocarbons by 1993 or 1994; this may limit
their application to relatively specialized products, for example, to perfume
meter-sprays in container sizes of 50 mL or less.
When flammable propellants are considered to be within the scope of
company operations, the most reasonable choices are isobutane and propane. In
some parts of the world the "natural blend" must be used. A typical natural
blend will consist of 60% nbutane, 20% isobutane, and 20% propane. It is a
broad distillation cut from the gas wells after de-ethanization and partial
de-propanization. In some areas, the hydrocarbon may contain large amounts of
other impurities. Some gas wells in Canada were found to contain over 50%
hydrogen sulfide and alkyl mercaptans (thiols), causing their closure. Wells
in Trinidad typically contain 12% unsaturates, such as propylene and
isobutylene, making them marginally useful for aerosol applications.
Propane/butanes from gas wells in Brazil contain 2.5 to 5.5% unsaturates.
Any contract filler or self-filler contemplating a change from'CFC to
hydrocarbon propellants should thoroughly investigate such things as
availability, purity, fire and building codes or regulations, the cost of
conversion, such as the construction of an outside gas house, safety
equipment, and electrical revisions. The product development and quality
control laboratories should be equipped with explosion-proof hoods,
ventilation, and other safety equipment.
When, available, dimethyl ether offers a relatively inexpensive
alternative to the hydrocarbon propellants. It does not have the potential
15
-------
problem of odor. It is less flammable (on an absolute, LEL, or other scale)
but it is also a very strong solvent.
The flammable HCFCs and HFCs are final options, but because of their
relatively high cost they may have a minor effect,on the worldwide aerosol
industry.
Concentrates
Most concentrates are available in the form of suggested formulations by
ingredient suppliers. They may be made especially for aerosol uses, or they
may be adaptable to aerosol applications. Some, like most paint products,
have to be drastically altered before they will work for aerosols.
A large collection of supplier samples and literature is a requisite of
any formulating laboratory. The literature should cover properties, uses,
compounding techniques, toxicological data and suggested prototype or starting
formulations. (Sometimes these formulas have somewhat more of the supplier's
product than is really needed.)
After a concentrate has been tentatively developed, there remains the
process of adding the correct type and amount of propellant, and using an
aerosol valve that will develop the desired spray pattern or foam puff. One
of the most important characteristics that the formulator looks for is
particle size distribution, which can be of paramount importance. If the
droplet size is too coarse, it can be decreased by one of the following
techniques;
• Increase the percentage of propellant;
• Increase propellant pressure and/or dispersancy;
• Use a vapor-tap valve or a larger vapor-tap orifice;
• Use a mechanical break-up button;
16
-------
• Add a low-boiling (volatile, easy breakup) solvent; and
• Reduce the quantity of polymers, thickeners, resins, adhesives, and
water.
Approximately 40-50% of the world's 8 billion aerosol products use vapor-
tap valves. Such valves have an orifice extending through the side or bottom
wall of the valve body and into the head space area. When the orifice of a
vapor-tap valve is' enlarged to decrease particle size, a price is paid. The
negative effects are listed below:
• A broader particle size distribution will generally result,
• A gradual coarsening of the spray may occur during use.
• The internal pressure will decrease, as air and the more volatile
propellant ingredients preferentially escape through the vapor-tap
orifice.
• The delivery rate will always be lower than without a vapor-tap, and
will decrease during'use, because of pressure reduction,
The potential problems with vapor-tap valves can be minimized by the
following techniques;
• Use the smallest vapor-tap hole that will suffice (a 0.25 mm size
may be a good starting point).
• Use a fairly large to large amount of propellant that disperses well
(reservoir effect),
• Use a pure propellant; otherwise, the more volatile ingredient will
be preferentially discharged, causing a pressure drop.
• Use reasonably large liquid orifices.
17
-------
• Emphasize any or all of the above in taller cans, since (near
emptiness) a liquid column of 150 - 250 mm will have to be
maintained in the dip tube just to bring the product into the valve
chamber. A greater dynamic pressure potential is needed, compared
with shorter can sizes.
As a rule, thin or driving sprays, or sprays with high delivery rates,
will be perceived by consumers as "wet" or "cold," although they may be
anhydrous. Wet sprays are usually disliked, except for the coating of
inanimate surfaces (such as a paint spray or bug killer); they are most
disliked for cosmetic items designed to be sprayed on the skin, such as
underarm antiperspirants or deodorants. The aerosol antiperspirant provides
an interesting challenge because large valve orifices must be used to prevent
possible valve clogging by the 7 to 12% aluminum chlorohydrate powder normally
present. Here, the vapor-tap valve, used with a mechanical break-up button,
provides a fine-particled. spray. The propellant content is in the 68-82%
range to give good breakup and to provide an adequate reservoir for the vapor-
tap.
Flammability
To devise a good aerosol product, a formulator must try to minimize the
risks of flammability and possible explosivity. It is a tribute to the
excellence of the aerosol packaging form that extremely flammable products can
be safely dispensed, if the user follows the label directions, and if the
formulator is able to make' allowances for reasonably foreseeable consumer
misuse. Flammability is a'potential problem when large amounts of product are
discharged at one time, as in some hair spray applications, painting,
waterproofing, and in the total release insect fogger (TRIF) products,
Flammability has also been a problem when containers are dropped on the valve
stem, causing it to bend or crack in such a way that the valve jams, releasing
a continuous spray. Consumers have sometimes panicked and thrown the can out
the window when this happens.
18
-------
The special case of the TRIF product will be described in more detail
later. The latches open on these products, allowing the entire contents of
the can, from 50 to 400 g, to be dispensed. Special low-flammability formulas
are needed to prevent harmful fireball effects if the spray is discharged too
close to pilot lights or other sources of ignition.
In the U.S., aerosol products are regulated according to type by three
federal agencies. Pesticides such as insecticides, disinfectants, herbicides,
and rodenticides are handled by the U.S. EPA. Household products such as
paints, automotive products, air fresheners, and window cleaners, are handled
by the Consumer Product Safety Commission (CPSC). Finally, all food, drug,
and cosmetic products are under the control of the Food & Drug Administration
(FDA). The EPA and CPSC require flammability labeling, according to test
method results; the FDA does not. The FDA merely states that products seen to
be too hazardous or that are inappropriately labeled will be seized and banned
from further marketing. As a result, approximately 70% of all aerosol
containers in the U.S. are marked "Flammable." Another 5%, such as many
anhydrous automotive products, are marked "Extremely Flammable." Many hair
sprays, underarm products, and other FDA-regulated aerosols are also marked
"Flammable," although this is not required.
In the U.S. and in most other countries, the standard test method for
flammability is the Flame Projection Test. Procedures and criteria vary
somewhat, but a can is normally sprayed through the top third of a candle
flame from a distance of 151 mm. If the spray ignites and carries the flame
forward another 457 mm (or further), the product is considered to be
"Flammable." The term "Extremely Flammable" is rarely used in other
countries. It relates to two tests, a flashback test and a closed cup flash
point test at approximately -28 °C. For the product to be marked "Extremely
Flammable," it must fail both tests: the flash back must extend to the
actuator at any degree of valve opening, and the cup test must indicate a
flashpoint of less than - 70C.
Although there are many shortcomings of the Flame Projection Test, which
was devised in 1952, it has been adopted by many countries. A number of
19
-------
techniques can be used to reduce the length of the flame in the Flame
Projection Test, so that a "Flammable" product can sometimes by "adjusted" to
a nonflammable one. For example, hair spray marketers prefer to sell sprays
that have flame projections in the 300 to 400 mm range (thus nonflammable).
However, these products are marketed with a "Flammable" label that is, in
fact, an overspecification.
Methods for reducing flame projection include the following options:
• Reduce the delivery rate;
• Reduce particle size (smaller particles burn out more rapidly and
move more slowly);
• Use a vapor-tap button, often with a mechanical breakup button
(actually a way to reduce both delivery rate and particle size).
• Add a nonflammable solvent, such as 1,1,1-trichloroethane or
methylene chloride, or a nonflammable or less flammable propellant
to suppress flammability.
• Present the product as a lotion, foam, mousse, whip, paste, metered
dosage (spray or foam, micro or macro) so that the test is passed
simply because' it cannot be meaningfully applied.
A relatively new concept of flammability arose in 1979 in the U.S. when
the Factory Mutual Research Corporation (owned by several insurance carriers)
was asked to look into the subject of aerosol hazards in warehouses. Tests
showed that many aerosols exploded in fires, producing large fireballs and
intense heating effects. Sprinkle systems need to be sized to reflect very
high fuel loading.
About 65% of the aerosol cans produced in the U.S. are anhydrous
formulations containing flammable solvents and propellants. These require
sprinklers capable of spraying from about 3,300 liters/m2 to 4,200 liters/m2
20
-------
(depending on the degree of water miscibility of the flammable, ingredients)
each minute, for control. Extremely fast response was also a requirement so
that the fire could be controlled while still in an early stage.
After a $2 million fire-testing program was .finally completed in 1989,
the aerosol industry participated in writing new codes and in rewriting others
designed to improve the safety features of warehouses, backstock storage
areas, and display areas. After a lengthy development protocol, these model
codes will be completed and implemented in 1991, after which it is expected
they will be adopted by legislative and regulatory officials in local fire and
building codes. Since the insurance companies that support the new codes are
usually multinational, some effects are already being felt in Europe as well.
Pressure
Most U.S. aerosols are formulated to a pressure as low as is consistent
with good operational performance across the anticipated temperature range of
their use. For example, hair sprays are expected to work well between 13° -
37°C, and reasonably well just outside these limits.
Pressure limits for containers vary only modestly among countries. In
the U.S., the so-called ordinary or non-specification can is permitted to hold
product with pressures up to 1,067 kPa abs. (9.85 bar - gauge) at 54.4°C. It
will not rupture below 1,546 kPa abs. (14,8 bar - gauge)'. Special cans with
14% and 28% higher pressure ratings are also available at an extra cost. They
only hold about 9% of the market. Aerosols of less than 118 mL capacity are
not regulated for pressure limits in the U.S. Most aerosol containers will
begin to deform at about 65°C and will rupture at 75*C or higher, depending on
can and product.
Materials Compatibility
The formulator's job is not complete when an acceptable product and
packaging system has been developed. Test packing is always needed to
establish data on weight loss rates, can and valve compatibility, organoleptic
21
-------
stability, etc. Hundreds of sad stories could be written about new products
that were inadequately tested, and then could-not be manufactured, eroded the
can, demulsified, changed color or odor, were subject to microbial
proliferation, grew inorganic crystals, or eventually threw down resinous
p r e c 1 p x t a t e s x n th e c on ta xne r, s we lied v a I've s shut or par t ly s hu t, blistered
can linings, became latent leakers, etc. No fewer than 36 cans per variable
should be test packed and checked--some at about 25°C and some at 4Q°C; some
upright and some inverted.
Tinplate cans do 'not corrode unless at least 0.008% of free water is
present. Above about 0.250%, greater concentrations of water will have no
additional effect on the rate of corrosion, xf any. Water has little effect
on aluminum cans. In fact, its virtual absence can sometimes allow anhydrous
alcohol (C2H30H) to attack aluminum cans to produce aluminum ethoxide
[ (C2H50)3A1] and hydrogen (H2) gas. Water is implicated in the well-known
ability of 1,1,1-trichloroethane to sometimes attack plain and lined aluminum
cans, but the mechanism is still unclear. Finally, water can facilitate
development of high pH values in hair depilatory formulas and certain others,
leading to aluminate (A102~) ion formation, plus hydrogen (H2) gas. Since
aluminum is amphoteric, it should only be used with formulas having a pH of
less than 12.0 at 25°C, and then only when 'reliably lined.
Xf a generalized, non-pitting corrosion pattern is seen, it is best to
use a lined or double-lined can. Detinning is generally a good sign, showing
that the tin (not the iron) is anodic. If pitting is detected, the formula
should be changed. Several options are described below:
• Remove the offending or causative ingredient if possible, such as
sodium lauryl sulfate, especially if chloride ion is present.
• Add corrosion inhibitors, such as sodium nitrite, sodium benzoate,
morpholme, or sodium silicates. (Do not use nitrites in
conjunction with primary or secondary amines, or N-nitrosamines will
very slowly form in situ. Many of these are carcinogenic.) From
0.05% to 0.20% inhibitor is generally sufficient.
22
-------
• Increase the pH to about 7,6 to 8.8, if possible, by adding
triethanolamine or ammonia (NH^OH Solution).
• Remove or minimize ionizing materials, i.e., those that permit
electroconductivity and thus promote galvanic corrosion reactions.
• Minimize chloride ion (especially). It is a very active corrosion
proraotor, even for underfilm corrosion. It is critical to minimize
chloride ion when materials such as sodium lauryl sulfate (which
contains it in some grades) or lauryl polyoxyethylene sulfates are
present.
• Sometimes specific corrosion inhibitors are required. Sodium lauryl
sarkosinate and sodium coco -B-aminopropionate surfactants are useful
for sodium lauryl sulfate. Coco-diethanolamide is good for non-
ionic surfactants. Virco-Pet 20 (composition proprietary, except
that it is an organic phosphate), is good for dimethyl ether and
water compositions.
• For some formulas, traces of moisture can be removed by using such
scavengers as propylene oxide or epichlorohydrin. (Very limited
evidence suggests that both may be mutagenic.) These chemicals are
never recommended for cosmetics.
Many formulations that are intensely corrosive to steel cans may be
conveniently packaged in lined aluminum containers. Examples are mousse
products and saline solutions. The latter contain 0,9% sodium chloride (NaCl)
in water under nitrogen pressure.
23
-------
SECTION 3
EXAMPLE NON-CFC ALTERNATIVE FORMULATIONS
COSMETICS, TOILETRIES, AND PERSONAL CARE PRODUCTS
Hair Spravs
In the U.S., hair spray (aerosol and pump-action) is the largest single
category of the $3,000,000,000 hair care market. Aerosol hair spray is also
the largest selling aerosol product. In 1988, about 488,000,000 units were
sold, at a retail value of about $1,150,000,000. The pump-spray alternative
has several detractions, such as finger fatigue during use, longer application
period, flexibility--and sometimes poor shape retention of the larger size
containers and occasional plugging of the meterspray valve. The formulations
must also be resistant to oxygen, since air is sucked back into the dispenser
with every actuation. The pump-action valve is rather costly, and this,
combined with a generally smaller fill volume, has necessitated a fairly high
price per unit of volume or weight. Sales are relatively small, compared with
the popular aerosol version. Both are normally anhydrous and flammable,
although there are formulation options for substantially reducing the flam-
mability of the aerosol product.
Hair sprays are normally formulated with 1.3 to 3.02 of film-forming
ingredients, commonly called polymers or resins. These materials tack down
the hair after the product dries for a minute or two, preventing the displace-
ment of strands or curls by body motion or wind. On the other hand, plasti-
cizers are included to ensure the flexibility of the entire hair mass, so that
it can retain a healthy bounce and not feel too stiff. A feature of some
formulas is that extra stiffness can be imparted by spraying on more product,
if a more sculptured or rigid coiffure is desired.
24
-------
The hair spray resin must have properties that include solubility in 95.5
vol* of anhydrous ethanol, a good feel on the hair, no stickiness or tackiness
in moist atmospheres, lustrous (healthy) appearance, good holding power, good
removability with shampoos, and sufficient flexibility to allow bounce and to
resist junctural fracture.
To achieve the ideal property mix, nearly all film-forming resins are
copolymers (dipolymers and terpolyraers). Of the seven or so used in the U.S.,
perhaps the most popular is Gantrex ES-225, made by the GAF Corporation.
Chemically, it is the monoethyl ester of polyvinylmaleate/maleic anhydride
copolymer, and it is normally purchased as a viscous solution of 50% solids in
anhydrous ethanol. For best results, the carboxylic acid moieties of the
polymer must be partially neutralized by the addition of certain amine
compounds. Another polymer, known as Gaffix, was introduced by the same
supplier in 1989 and is said to provide not only hair fixative properties but
hair conditioning as well. (The same quaternized material is recommended for
hair mousses.)
The type and amount of resin and plasticizer (if needed) enables the
final product to be sold as a Gentle Hold, Regular Hold, Extra Hold, Super
Hold, or Ultimate Hold formulation. The differences between such products
vary: a Regular Hold by one marketer may have more holding power than an
Extra Hold by another. In popularity, the Extra Hold and its equivalents have
a slight advantage, closely followed by the Regular. While hair sprays
normally fall between the "price/value" (utility) and "luxury image" ends of
the hair care market, many sell for several times the price of others. The
"luxury image" products do not usually indicate their hair-holding ability,
preferring to suggest that they are just right for all users.
During the 1970s, many hair sprays were extended to provide supplementary
benefits by the inclusion of such minor ingredients as Vitamin E (alpha
tocopherol), silicones, myristyl myristate, aloe extract, elastin, and protein
hydrazolates. The products of the 1980s still use many of these special
ingredients, but also claim to be "energizing," "volumizing," "revitalizing,"
25
-------
"nourishing," "elasticizing," and good for "sun survival." Since hair is dead
matter,, some of the claims refer to the scalp, not to the hair shaft.
The formulas in Table 6 illustrate ways of using both hydrocarbons and
dimethyl ether as propellants.
The use of water with Gantrez and Resyn copolymers in hydrocarbon-
propelled hair spray systems has been the subject of U.S. Patents held by the
American Cyanamid Company, Patents have also been issued covering the
inclusion of carbon dioxide as an additional propellant in dimethyl ether
systems. Both carbon dioxide and nitrous oxide are extraordinarily soluble in
dimethyl ether, dissolving at about 3.70% and 3.91%, respectively, for each
one bar of pressure increase at 21aC.
In the U.S., the hydrocarbon hair sprays have generally been packed in
lined tinplate or (sometimes) aluminum cans. In other countries, plain
tinplate cans are often used. The dimethyl ether formulas are usually packed
in plain tinplate cans or in aluminum cans with linings of PAM (polyamidimide)
or special epon-phenolic types.
The Precision Valve Corporation has developed effective valves for both
hydrocarbon- and dimethyl ether-based hair sprays, using their well-known 2 X
0.50 mm Aquasol® stem. Other components include a 0.50 mm KBST (Mechanical
Break-up Straight Taper) button and butyl rubber stem gasket. The very high
solvency effects of dimethyl ether require special gaskets for valves. For
valve cups, cut gaskets of Butyl U105, Butyl U133, and Chlorobutyl CLB-82 (all
by the American Gasket and Rubber Company) have performed well commercially.
The Precision Valve Corporation's Polyethylene-Sleeve gasket also gives good
performance when used with tinplate cans, as do the polyethylene and ppolypro-
pylene laminates.
Since the drying time of alcohol is 29 times as quick as that of water,
it may be surprising to know that the drying time of all four hair spray
formulas is essentially the same. This is because the formation of
26
-------
TABLE 6. HAIR SPRAY FORMULATIONS USING BOTH HYDROCARBON AND DIMETHYL
ETHER PROPELLANTS (Regular Hold)
Ingredients
Formula
A
Formula
B
Formula
ea
Formula
Da
Gantrex ES-225 (50% in Anhydrous
4.00
4.00
....
e thano1)
Resyn 28-2930 (100%)b
2.50
2.50
Amino-methyl-propanol (95%)
0.09
0.20
0.18
N,N-Dimethy1-octadecylamine
0.29 ¦
Dimethyl Phthalate
0.03
0.03
D.G. Fluid #193°
0.02
0.02
0.04
0.06
Disodium Dodecylsulfosuccinate
0.20
0. 20
Sodium Benzoate
0.08
0.08
Fragrance
0.10
0.10
0.15
0.15
Deionized Water
8.79
16.00
32.00
S.D. Alcohol 40-2 (Anhydrous)
.67.56
61.00
44.80
28.83
Propellant A-31 or A-40d
28.00
26.00
Dimethyl Ether
36.00
36.00
Pressure (532 mm Vacuum Crimp,
2.2 bar
2.5 bar
2. 5 bar
3.7 bar
21°C)
Delivery Rate (g/sec - 21°C)
0.50
0.54
0.60
0.65
Flame Projection (mm - 21"C)
460
425
250
225
Flash Back to Button8 (mm - 21°C)
60
50
0
0
"Formulas C and D are based on information originally developed and published
by Dr. Leonidus T. Bohnenn of Aerofako, BV.
Hfinylacetate/crotonic acid/vinyl neodecanoate copolymer, made by National
Starch & Chemicals Corporation, U.S. (It can be replaced with Gantrez ES-225,
but some detinning may occur at 35°C or above.)
°A water-soluble silicone copolymer, made by the Dow-Corning Corporation, U.S.
dA-4Q is an alternative propellant blend, consisting of 10% propane and 90%
isobutane by weight. The pressures and other data for Formulas A and B are
based on A-31; 100% isobutane.
BAt full delivery rate. If the valve is throttled, the flashback of Formulas
A and B will become 152 mm; i.e., to and touching the actuator.
27
-------
hydroalcoholic dimethyl ether azeotropes greatly accelerates the evaporation
rate of water. (This feature is useful in dimethyl ether formulations for
personal deodorants, paints, and several other aerosol products.)
Until recently, methylene chloride, and, rarely, 1,1,1-trichloroethane
were included-in U.S. hydrocarbon hair sprays. These solvents were removed in
between 1985 and 1988 because of the alleged carcinogenicity of these sub-
stances.
Since the early 1950s, methylene chloride has been used in billions of
cans of hair sprays. It increases resin solvency, decreases flammability,
promotes evaporation rate, and causes the deposition of a smoother film with
less junctural beading. Concentrations of up to 25% have been tolerated by
both the dispenser and the consumer. In greater amounts, however, the odor
and solvent effects become more significant. For instance, plastic eyeglass
frames may glaze over time, and contact lenses may blush temporarily. A few
individuals are sensitive to methylene chloride and may develop rashes or
itching of the neck.
Hair Lusterizers
Many people, but especially those Blacks, Hispanics, and others with very
curly hair, have little need for standard hair sprays, but they often use hair
conditioning and lusterizing sprays that convey the sheen and look of natu-
rally healthy hair. Some formulations for these products appear in Table 7.
Both hair sprays and hair lusterizers are sold in scented and unscented
versions. The "unscented" form actually has about 0.02 to 0.03% of a non-
descript floral fragrance in it to cover the slight chemical odors of the
other ingredients. They are also sold for both consumer and professional end
uses. The professional cans are often quite large [65 mm X 238 mm (666 mL
fill)], and are generally of tinplate.
28
-------
TABLE 7. HAIR CONDITIONER SPRAY FORMULATIONS
Ingredients
Formula
A
Formula
fi
Formula
C ,
Formula
D
Isopropyl Myristate®
Mineral Oil; US?
Isodecyl Oleate
Volatile Silicone Fluid
Odorless Mineral Spirits
PPG-12/PPG-50 Lanolins
Pluriol 9400c
Mink Oil
Fragrance
Deionized Water
S.D. Alcohol 40-2 Anhydrousd
Iso-Butane (A-31)
Propane/iso-butane (A-46)
Dimethyl Ether
Pressure (532 mm Vacuum Crimp)
(bars, at 21°C)
5.0
35.0
0.1
0.1
19.8
40.0
3.6
3.0
20.0
0.1
0.1
76.8
2.6
2 ; 0
20.0
3.0
0.1
0.1
44.8
30.0
2.4
2.0
20.0
3.0
0.03
0.07
0.1
15.0
24.8
35.0
2.9
aCosmetic Grade. May be replaced by isopropyl palmitate.
bAs Cyclonethicone F-251 (Dow-Corning Corporation). A blend of 25% Tetratneric
Ring Compound and 75% Pentameric Ring Compound. The dimethylsilicone of 0.65
cstks. Viscosity may also be used.
CA propylene oxide - ethylene oxide surfactant polymer,
dSpecially Denatured ethanol. To make, add 400 g t.Butanol and 45 g of
Brucine Sulfate to 3,784 liters of ethanol.
29
-------
Hair Mousse
The mousse (French word for "foam") was first introduced in an aluminum
can in the U.S. in 1973 as "Balsam and Body" foam. The French-based-firm of
L'Oreal, S.A., which researched this product type from 1975 to 1980, required
a hair setting and conditioning foam that would leave the hair softer, more
manageable, easier to brush, shiny, free of frazzles, having a good handle and
slip, and with good body control and able to resist fly-away situations. The
product was launched in Europe in 1981 and in the U.S. and Japan in 1983. In
1988, world-wide sales were about 270,000,000 aluminum cans; about half of
this number was marketed in Europe.
To achieve both hair set and conditioning characteristics, any one of
three classifications of a specialty polymer must be used:
• A combination of a slightly anionic "hair spray" film former, with a
compatible cationic hair conditioning polymer;
• A cationic conditioning polymer that can also function as a hair-
setting agent; or
• An amphoteric hair-setting and conditioning polymer, sometimes
augmented by the addition of quaternary conditioning ingredients.
One of the more popular compounds is Gafquat 755N (20% dispersion in
water), which is a quaternary ammonium polymer formed from dimethyl sulfate
and a copolymer of vinyl pyrrolidone and dimethylaminoethyl methacrylate. The
second approach is to use a two-component system, such as a combination of GAF
Corporation's Copolymer 845 (20% in water) poly(vinylpyrrolidone/dimethy1-
aminoethyl methacrylate, for hair setting plus a quaternary, such as Ciba-
Geigy's Bina Quat 44C: hydroxyl-cetylammonium phosphate. Supporters of the
two-component system claim they can adjust the degree of set and degree of
conditioning independently, to conform to perceived marketing requirements. A
large number of other products are available, but the anionic and cationic
moieties have to be selected for compatibility or precipitation may occur. A
30
-------
well-quaternized resin will exhaust substantively onto the towel-dried hair
when the product is worked into it following shampooing. In a typical case,
about 175 mg per 100 g of hair will exhaust from dispersions of 0,3% concen-
trations or higher in the product itself. This 0.175% level is all at the
hair surface, and provides such properties as silkiness, shine, volume,
handle, lack of fly-away, lubricity, manageability, and anti-static proper-
ties. It also avoids any sense of limpness or buildup on the treated hair.
After the hair set and conditioning agents are chosen, an emulsifier must
be selected. A minimum amount should be employed, so the user can apply the
mousse without needing to rinse the excess out of the treated hair. This is
especially important in the case of emulsifiers, where the excess can turn the
hair slightly waxy, sticky, and dull. Some common selections include oleyl
diethanolamide, ethoxylated (9 mol) octylphenol, polyethylene glycol (10 mol)
ether of stearyl alcohol, mixed monooleate esters of sorbitol and sorbitan
anhydride with an average of 20 moles of added ethylene oxide (Polysorbate 80)
and polyethylene glycol (20 mol) ether of stearyl alcohol (Brij 720 or PEG-20
Stearate). In general, the most effective are nonionic ones at levels of 0,3
to 0.7%. The emulsifier must ensure good dispersion of the propellant, good
foam formation, and some initial instability of the foam when applied. It
must quickly collapse when rubbed onto the wet hair. Good wet and dry
combing, foam wetting, moisture retention, and emmolliency are generally
conveyed by the use of these ethoxylates and propoxylates.
Like the hair sprays and lusterizers, mousse products often contain a
host of specialty ingredients at levels often ranging from 0.001 to 0.100%.
These include aloe vera extract, jojoba oil, chamomile extract, protein
derivatives, elastin, allantoin, other quaternaries, birch (tree) extract,
marigold (flower) extract, walnut leaves (tree) extract, and various sun-
screening agents. They may or may not convey any real benefit, depending on
the concentration used in the formula. Some mousse products also contain
colorants or dyes, of which perhaps the most common is FD&C Yellow #7 (in the
U.S.), used at 0.002 to 0.008%. All mousses are perfumed.
31
-------
Bacterial proliferation can occur in some mousse formulas, so they are
often protected with 0.10% methyl p.hydroxybenzoate and 0.05% n.propyl
p.hydroxybenzoate. Other, more powerful and broader spectrum preservatives
are now being favored, such as Kathon CG (Rohm & Haas Company) and Dowicil 200
(Dow Chemical Company). In general, the finished mousse concentrate or
aerosol should be able to pass a microbial Total Plate Count test with a
reading of "less than 10 organisms per mL." It is also recommended that the
tank, hoses, pumps, filters, and filler bowls be sanitized and that the
deionized water used in batchmaking be first heated to 70°C to kill pseudo-
monads and most other microorganisms.
The usual propellant for mousse products ia A-46 (15 weight % propane, in
85 weight % isobutane), which develops mousse pressures in the area of 4.0 bar
at 21.2°C. The usual amount is 6.5 to 7.5%, but some products use as much as.
15%. For some specialty products, such as mousse used on babies, absolutely
no evidence of flanunability can be tolerated. With the straight hydrocarbon
formulas, touching a lit match or lighter to the surface of the foam will
produce a momentary ignition. This can be eliminated by using a propellant
blend that includes 30% or more HFC-152a. The A-46 and HFC-152a can be
purchased as a blend, premixed by those fillers who have blending stations, or
added consecutively using two separate gassing machines. Because the HFC-152a
is only present in concentrations of 2% or so, the cost penalty is relatively
low.
The general considerations involved in formulating a mousse hair set and
conditioning product have been described, and some illustrative formulations
will now be presented. Table 8 describes four formulations fully, giving
first the U.S. Cosmetic Ingredients Dictionary (CTFA-CID) terminology,
followed by the chemical name, brandname(s), and source. Table 9 describes
four additional formulations in a format of decreasing order of ingredient
concentration (except that ingredients whose concentrations are less than 1%
may be placed in any order), in accordance with U.S. Food and Drug Administra•
I
tion (FDA) regulations. These regulations require ingredients of food, drugs,
32
-------
TABLE 8. MOUSSE HAIR SET AND CONDITIONING PRODUCT FORMULATIONS
Formula A
% fw/w)
Soft Set Firm Set,
Polyquaterniura 4 0.60 1,00
Copolymer of hydroxy-methylcellulose
and diallyl-dimethyl ammonium chloride
Celquat L-200 (100% A.I.) by National
Starch & Chemical Corporation
Deionized Water 75.85 75.25
Dimethacone 0.15 0.20
Dimethyl silicone derivative emulsion
DC Silicone Emulsion by Dow-Corning Corp.
Tallow Trimonium chloride (and) isopropanol 0.10 0.15
stearyl/palmityl trimethyl ammonium
chlorides; 75%, in isopropanol
Arquad T-50 (75% Active Ingredient)
by the Industrial Chemicals Division of
Arraak Corp.
Octoxynol 9 0.15 0.30
Ethoxylated (9) n.Octylphenol
Triton X-100, by the Rohm & Haas Corp.
Emulsifying Wax NF 0.15 0.10
Fatty alcohol derivative - Self emulsifying
Polawax A-310, by Croda, Inc.
Polawax A-310, ,(100% A.I.) by Croda, Inc.
Ethanol SD40 14.90 14.88
Ethanol (Denatured #40; 100%)
S.D. Alcohol 40; anhydrous, by U.S. Industrial
Chemicals Division
Perfume Oil (Floral) 0.10 0.12
Continued
33
-------
TABLE 8, (Continued)
Formula A
Ingredients
% (w/w)
Propellant A-46
IS wt, % prop^n6 & SS wtiX isobutdns
8.00
8.00
A-46 Propellant by Phillips Petroleum Co,;
Specialty Products Division
Formula B
Ingredients
% fw/w)
Quaterniura 11
7.00
Poly (vinylpyrrolidone/dimethylaminoethyl
methacrylate)
Copolymer 845 (20% Solids in Water) by GAF Corp.
Polyquaternium 16 3.50
Hydroxyethyl cetyldimonium phosphate (100% A.I.)
Bina-Quat 44C (100% A.I.) by Ciba-Geigy Corp.
Cocoamid DEA 1.00
Coconut acids diethanolamine condensate (1:1)
(Free of soap and amide esters) (Superamide)
Standamid SD (100% A.I.) (Henkel Chemical Co.)
Tallow Alkoraium Chloride 0.50
Dimethyl benzyl tallow ammonium chloride
Incroquat S85 or SDQ-25 (Croda, Inc.)
Deionized Water 77.65
Methylparaben 0.08
Methyl p.hydroxybenzoate
Nipagin M (Nipa Laboratories, Ltd.)
Perfume Oil (Floral) 0.26
FD&C or D&C (Color)
0.01
Propellant A-46
16 wt % propane & 84 wt % isobutane
10.00
A-46 Propellant by Phillips Petroleum Co.;
Specialty Products Division
Continued
34
-------
TABLE 8. (Continued)
Formula C
Ingredients % (w/w)
Polyquaternium 11 1.32
A quaternary ammonium polymer formed by the
action of dimethyl sulfate on a copolymer of
vinylpyrrolidone and dimethyl amino ethyl methacrylate,
Gafquat 734, (50% A.I. in Ethanol), by the GAF Corp.
Polyquaterium 4 1.00
A copolymer of hydroxymethylcellulose and diallyl-
dimethyl ammonium chloride.
Celquat H60 (100% A.I.) by National Starch and Chemical Corp.
Silicone 0.15
Silicone polymer, end-blocked with aminofunctional
groups
Cationic Emulsion 929 Dow-Corning Corporation
Oleamidpropyl Dimethylamine Hydrolysed Animal Protein 0.20
Oleylamidopropyl diethylamine hydrolysed animal protein.
Lexein CP-125, by the Inolex Corp.
Potassium Coco-hydrolysed Animal Protein 0.14
Animal protein hydrolysed in boiling potassium cocoate
soap solution.
Lexein S620, by the Inolex Corp.
Aloe vera " , 0.05
Aloe vera
Aloe Vera: Pure Extract (90% A.I. Powder),
Terry Chemical Company
PEG 150 0,26
Hydro-(ethyleneoxide 150) alcohol
Carbowax 8000, by Union Carbide Corp. or Polyethylene
Glycol 6000 by Dow Chemical Company
Quaterraium 52 0.20
Dibutyl sebacate
Dehyquart SP, by Henkel Chemical Company
Continued
35
-------
TABLE 8. (Continued)
Formula C
Ingredients
Ethanol SD40
Ethanol (specially denatured #40; 100X)
S.D. Alcohol 40; Anhydrous, by Shell Chemical Co.
Polysorbate 20
Mainly the monolaurate ester of sorbitol and
sorbitol anhydrides, condensed with 20 moles of
ethylene oxide,
Tween 20 by ICI Americas, Inc., or Nikkol TL10
or TL10-EX by the Nikko Chemical Company
Fragrance (Floral)
FD&C or D&C (Color)
Deionized Water
Propellant BIP-55
Ethane
Propane
Iso-butane
n.Butane
Pentanes
Hexanes
Unsaturated Hydrocarbons
Sulfur compounds
Water
0.290 w.X
30.728
26.509
39.759
2.700
0.010
0.001 maximum
0.0005 maximum
0.0025 maximum
Propellant IBP-55 by Phillips Petroleum Company,
Specialty Products Division.
% (w/w)
3.00
0.05
0.209
0.001
85.42
8.00
Formula D
Ingredients
Polyquaternium 11
Quaternary ammonium polymer of dimethyl sulfate
and the copolymer of vinylpyrrolidone and
dimethylarainoethy1 methacrylate.
% (w/w)
5.00
Qafquat 755N (20% in water), by GAF Corp.
Continued
36
-------
TABLE 8, (Continued)
Formula D
Ingredients % (w/w)
PVP 1.00
Polyvinylpyrrolidone (Mol. wt. = 30,000)
PVP (K-30) (GAF Corp.)
Carbomer 941 15,00
Polymer of acrylic acid, cross-linked with a
polyfunctional agent
Carbopol 941 (Use as 2.0% in Water) B.F. Goodrich & Co.
Ammonia 0,28
Ammonium Hydroxide (29% in Water)
Steardimonium Hydrolysed Animal Protein - Purified. 0.28
Stearyl dimethyl ammonium modified hydrolysed protein
Croquat SP (Croda, Inc.)
Nonoxynol- 20 0.28
Ethoxylated (20) n.nonylphenol
Igepal CO-850 (GAF Corp)
Steareth-2 0.28
Polyethylene glycol (2) ether of stearyl alcohol
CH3 (CH2 ) 16CH2 (OCH2CH2) 2oh
Brij 72 (ICI Americas, Inc.)
Polysorbate 20 0.50
Mainly the monolaurate ester of sorbitol and sorbitol
anhydride, condensed with an average of 20 moles of
ethylene oxide.
Nikkol TL10 or TL10-EX (Nikko Chemical Co.)
Methylchloroisolthiazolinone and Methylisothiazolinone
Iathon CG (Rohm & Haas Company)
Fragrance 0.24
Deionized Water 68.00
Continued
37
-------
TABLE 8. (Continued)
Formula D
Ingredients % (w/w)
Hydrofluorocarbon 152A 6.40
1(X"D i fluore tnane
Dymel-152 (E.I, DuPont de Nemours & Co., Inc.)
Genetron-152a (Allied-Signal Corporation)
IsobuCane 2.74
Isobutane A-31 (Phillips Petroleum Co,)
Aeron A-31 (Diversified Chemicals and Propellants Co.)
38
-------
TABLE 9. INGREDIENT LISTINGS OF OTHER MOUSSE HAIR SETS
AND CONDITIONERS3
1. 3CYZ Co. Professional Designer Mousse
So Airv-light Extra Firm Alcohol Free With Sunscreen
Water
Hydrofluorocarbon 152A
1s obutane
*Polyquaternium-11
*DEA-Me thoxyc innamate
Polyquaternium-4
Dimethacone Copolyol
Fragrance
*Isosteareth-10
Sodium Cocoyl Isethionate
Methyl Paraben
*Lauramide DEA
*DMDM Hydantoin
2. DO-GLO XYZ Co, Alcohol-Free Styling Mousses •
A 230-gram fill in aluminum can
Ultimate Hold - for all Hair
Water
Isobutane
PVP/Dimethylaminoethyl methacrylate copolymer
Polyquatermium 4
*Diphenyl-dime thicone
*Lauramine Oxide
DMDM Hydantoin
Fragrance
*Quaternium 18
Butane
*Airanonium Laureth Sulfate
*Disodium Ethylenediamine Tetraacetate (EDTA)
Citric Acid
Continued
39
-------
TABLE 9. (Continued)
3. DO-GLO XYZ Co, Alcohol-Free Styling Mousses
A 230-gram fill in aluminum can
Extra Body - for Fine Hair
Water
Isobutane
Polyquatermium 4
Propane
¦*Lauramine Oxide
Propylene Glycol
*0ctyl Salicylate
Panthenol
*Silk Amino acids
*Keratin Amino acids
*Hydrolysed Animal Keratin
Butane
Citric Acid
DMDM Hydantoin
Fragrance
*Disodium Ethylenediamine Tetraacetate (EDTA)
4. DO-GLO XYZ Co. Alcohol-Free Stvline Mousses
A 230-gratn fill in aluminum can
Moisture Rich - for Dry or Damaged Hair
Water
Propane
Isobutane
*Acetaraide Monoethylamide (MEA)
PVP/Dimethylaminoethylinethacrylate Copolymer
Butane
Cocamide Diethanolamide (Superamide)
Panthenol
(N-Pantothenylaraindoethyl) disulfide
*Glyeereth-26
*PEG-150 Distearate
Sodium Lactate
*Sodium PCA
Collagen
40
-------
TABLE 9, (Continued)
"Ml ingredients are listed in decreasing percentages, except for those
present in concentrations of less than 1,0 percent,
•*These ingredient designations are identified chemically in the following, way;
Acetamide MEA; Acetamide Monoethylamide Lipamide MEAA (Lipo Chemicals,
Inc, )
Ammonium Laureth Sulfate: Ammonium salt of ethoxylated (1-4) lauryl '
Sulfate Carsonol ALES-4 (Lonza Chemical Corp.)
DEA-Methoxycinnamate: Diethylaminomethoxycinnamate (Sun Screen Agent)
Diphenyl-trimethicone; Silicone 556 Fluid (Dow-Corning Corporation)
Disodlum EDTA: Disodium Ethylenediaminetetraacetate
DMDM Hydantoin: 1,3-Dimethylol-5,5-Dimethyl Hydratoin
Glycereth-26; Polyethylene Glycol (26) Glyceryl Ether Ethosperse G-26
(Glyco Chemical Company)
Hydrolysed Animal Keratin: Keratin, hydrolysed
Isostreareth-10: Polyethylene Glycol (10) Ether of Isostearyl Alcohol
Keratin: Keratin Amino Acids Kerapro (Hormel Company)
Lauramide DEA: Laurie Acid - Di-ethanolarnide (1:1) Condensate Super-
amide
Lauramine Oxide: n.Lauryl-dimethylamine oxide
Octyl Salicylate: 2 - Ethylhexyl Salicylate C15H„03 (Sunarome WHO-Felt or.)
PEG-150 Distearate: Polyethylene Glycol (150 mol) Distearate Lipopeg
6000-DS (Lipo Chemicals, Inc.)
Polyquaternium 11: A quaternary ammonium polymer formed from dimethyl
sulfate and a copolymer of vinylpyrrolidone and
dimethyl amino ethyl methacrylate.
Quaternium 18: De(hydrogenated tallow) Dimethylammonium Chloride
Adogen 442 (Sherex Corporation)
Silk Amino Acids: Amino Acid Blend, derived from Silk Protein (Croda,
Inc. )
Sodium PCA: Nalidone (UCIB) U.S. Distributor: S.S.T. Corporation
(Clifton, NJ)
41
-------
and cosmetics to be listed on the product label in this fashion, unless they
are for professional or institutional use.
Containers for Hair Setting and Conditioning Mousses-
Mousse formulas are normally finished to a pH value of approximately 5.5'
to 6.5 at 25°C. They are either aqueous or hydroalcoholic and contain
surfactant wetting agents and a high concentration of chloride ion, a well-
known corrosion promoting agent. It is not surprising that they are corrosive
to steel and tinplated cans and may even attack aluminum cans unless they are
well lined. Many mousse formulations contain corrosion inhibitors, such as
sodium benzoate, coco-diethanolamide, and amino groups to provide additional
shelf-life stability.
During 1984 and 1985, a large amount of work went into developing well-
lined tinplate cans for mousse formulas to take advantage of the much lower
prices of tinplate. In 1984, one major marketer introduced a low-priced
mousse in a 45-mm diameter tinplate (necked-in) can. Special techniques were
used to make the formula less aggressive, and the can was heavily double-lined
with an Organosol hydridized vinyl coating system. The product is still doing
well on the market. The only other mousse products in tinplate cans are lines
of large, salon-type mousse products sold to a number of marketers by one
formulating house. The cans are 52 mm in diameter by approximately 190 mm in
length. They have necked-in construction. They are made only by the Conti-
nental Can Unit of the United States Can Company and, uni_qucly, use a third
body lining (after welding and flanging) as a repair coat, to cover up any
abrasions or scratches made during manufacture. These cans contain 298 g of
product. A developmental can of polypropylene-laminated tinplate or tin-free
steel is performing well with mousse products after a year of storage.
Aluminum cans for mousse applications are typically 38, 45, or 52 mm in
diameter and are up to 165 mm long. All are of one-piece construction and are
heavily single or double lined. The usual epon-phenolic linings for aluminum
cans are sometimes inadequate for mousse products and have generally been
replaced with linings made of pigmented epoxy-phenolics, PAM clear polyamid-
42
-------
imide, and the popular Micoflex L6X392 beige-pigmented vinyl Organosol. In
some cases, two separate linings of the same material are applied.
Nearly all valves for mousse hair care products use aluminum mounting
cups coated on the outside and lined on the inside surfaces. Numerous
problems have arisen from trying to make a good seal, especially in the case
of the larger-diameter 52- and 66-mm cans. Bonded polyethylene sleeve gaskets
(an exclusive development of the Precision Valve Corporation) are satisfactory
if the new Ring Seal mounting cup contour is used, as are the full-coverage
polyethylene laminate gaskets--again, if a special contour valve cup is used.
These gaskets require a special mousse-resistant adhesive if continuing
attachment to the inner surface of the valve cup is a marketer requirement.
Otherwise, the laminate will separate eventually and droop slightly. Some
technical experts are concerned about the possible corrosivity of concentra-
tion cells that can be created between the laminate and unprotected aluminum
cup. Any liquids that may accumulate there must enter by permeating the
polyethylene; therefore, unknown compositions and concentrations may form.
Also, the adhesive is generally an excellent barrier material, but this
advantage is lost if delamination occurs.
Most hair care mousse products are designed to be vertical acting. Full
coverage of the mounting cup is an aesthetic benefit. The "pad-and-smokes-
tack" type is popular, as is the tilt-action, simple "smokestack" design.
Foam spouts are either white or the color of the base coat of the can. The
protective cover will either fit over the spout or valve cup outside diameter,
or be designed to have the same diameter as the can, for a cylindrical look.
Many U.S. marketers are testing the Fibrenyle Ltd. "Petasol" or PET
(polyethylene terephthalate) plastic bottles for mousse applications, with
good results. One problem that must be resolved is that the U.S. Department
of Transportation (DOT) will not permit interstate shipments of non-metallic
aerosol containers if their capacity exceeds 118.3 mL because of a regulation
that dates back to 1951, when the only non-metallic aerosol containers were
those made of glass. Special exemptions based on impressive arrays of test
43
-------
data, including drop test results, have now been requested. Meanwhile,
several new bottle shapes are being developed.
Other Mousse Products
The original hair setting and conditioning mousse products of 1981 and
later have made it possible for marketers to successfully introduce an
impressive number of related foam products. Several still involve various
aspects of hair care, such as hair sheens or lusterizers, hair depilatories,
dandruff control foams (using zinc pyrithrone or an alternative dandricide),
hair coloring mousses, and mousse products to help control ear itch and "jock
itch," a trichophytal fungal mycosis of the pubic area related to the well-
known "Athlete's Foot" problem. Other hair care products include baby oil
formulas, baby shampoos, curl activators, and products that promise a hair
thickening effect. A hair restorative material is now being sold in mousse
form.
The remaining second-generation mousse products are generally for skin
care. They include make-up items, baby oil formulas (again), sunscreens,
facial cleansing foams, hand creams, skin smoothing (20% talc) products,
cationic skin emollients, dewrinkler formulas, etc. Mousse products can be
used to contain and deposit large amounts of specialty oils on the skin, such
as a product that contains 25% jojoba oil (Wickenol 139, Dow-Corning Corp.),
which claims to give the skin a healthy sheen and superior lubricity.
The specialty "mousse gels" consist of lines of products that deliver as
clear or translucent gels but spring into mousse foams on contact with the
hand. Table 10 presents several formulations illustrating these newer
products.
The mousse packaging system is an ideal vehicle for dispensing sunscreens
and suntan lotions as foams that quickly break up on mechanical shearing to
produce exceptionally even matte finish results. The first to introduce this
product was Schering-Plough, Inc. as one of several package forms for Copper-
tone. More recently, in 1984, the Golden Sun Company introduced their Sun
Goddess Body Mousse Protective Sun Tan products in a 170-g filling weight.
44
-------
TABLE 10. SPECIALTY MOUSSE FORMULATIONS
Formula E
Hair Sheen and Conditioner
Ingredients % fw/w)
Stearimidopropyl Cetaryl Cimoniura Tosylate (and) 0.50
Propylene Glycol. (Ceraphyl 85, by Van Dyk & Co., Inc.)
Quaternium 26 0,75
(Ceraphyl 65, by Van Dyk & Co., Inc.)
i
C9-11 Isoparaffins (99+% C9-Cu Branched Paraffinics) 20.00
Isopar K, by Exxon, Inc.
Isodecyl Oleate 4.00
C12-15 Alcohols Benzoate 1.00
Fragrance 0.25
Deionized Water 68.50
Isobutane A-31 (Aeropres Corp.) (Propellant A-46) 4.25
Propane A-108 (Aeropres Corp.) (Propellant A-46) 0.75
Note: The foam may be destabilized by adding 0.5% of a volatile silicone
such as CTFA Cyclomethicone, alcohol, or by replacing part or all of
the hydrocarbon propellant (A-46) with hydrofluorocarbon 152 (CH3 -
CHF2) . Stability can be increased by adding cetyl alcohol.
Formula F
Baby Shampoo and Conditioner
Ingredients % (w/w)
Sodium Laureth (3) Sulfate [Sodium Lauryl (3 ETO) Sulfate] 40.00
Cocoamidopropyl Betaine (Cocoamidopropyl dimethylglycine) 16.00
Aerosol 30 by American Cyanamid Company, or Velvetex
BA-35 by the Henkel Chemical Company.
Benzyl Alcohol • 0.25
Continued
45
-------
TABLE 10. (Continued)
Formula F (Continued)
Ingredients % (w/w)
Methyl p.Hydroxybenzoate 0,25
PEG-150 [H - (0CH2 -CH2)150OH] Carbowax 8000 by Dow 0.25
Chemical Company.
Fragrance 0.25
Deionized Water 37.00
Isobutane A-31 (Aeropres Corporation) (Propellant A-46) 5.10
Propane A-108 (Aeropres Corporation) (Propellant A-46) 0,90
Note: The first two ingredients may be replaced with 34.00% Disodium
Oleamido PEG - 2 Sulfosuccinate, 20.00% Sodium Laureth (3) Sulfate,
and 2.00% Quaternium 22 substantive conditioner and humectant. The
last item is available as Ceraphyl 60 from Van Dyk & Company, Inc.
' Formula G
Easy-Spreading. Hair-Fixative Mousse
Ingredients ; % (w/w)
Ethyl Ester of PVM/MA Copolymer (Gantrez ES-225, by the 5.00
GAF Corporation; 50% A.I. in Ethartol)
Dimethicone Polyol (Surfactant 193 Fluid, by Dow-Corning 0.50
Corporation)
Amino methyl propanol (95%) min.) AMP-95, by the IMC Corp. 0.20
Fragrance 0.20
Ethanol (Anhydrous Basis) S.D. Alcohol 40 (200°), by 10,00
Publicker Industries, Inc.
Deionized Water 75.10
Isobutane A-31 (Technical Petroleum Company) 7.65
Continued
46
-------
TABLE 10. (Continued)
Formula G (Continued!
Ingredients % (w/w)
Propane A-108 (Technical Petroleum Company) 1.35
Note; The water-soluble 193 Surfactant acts to plasticize the copolymer
and to enhance the spreadability of the resin on the hair. It also
enhances foam building and foam stability. The possible need for a
preservative should be investigated, although most of these formulas
do not need one,
fs
I Formula H
Alcohol-Free Mousse for Damaged Hair
Ingredients , % (w/w)
Polyquaternium 11 (Gafquat 755N by GAF Corp.) 7.50
Blend of Trimethylsilylamodlmeticone, Octoxynol 40, 1.00
Isolaureth-6 and a glycol. (Dow-Corning Q2-7224;
Dow-Corning Corporation)
Oleth-20 (PEG 20 Ether of Lauryl Alcohol) (Brij 98, by 0.50
IC1 Americas, Inc.)
Fragrance 0.20
Deionized Water 81.80
Isobutane A-31 (Technical Petroleum Company) (Propellant A-46) 7.65
Propane A-108 (Technical Petroleum Company) (Propellant A-46) 1.35
Note: The Dow-Corning Q2-7224 conditioning agent provides improved wet and
dry combing and imparts a good handle or feel to the hair. The
agent is particularly effective on damaged hair.
Combinations of about 3.0% Polyquaternium 11, 0.3% Polyquaternium
10, 0.3% Steareth 10 (Brij 76) and 0.15% PEG-2 Oleammonium Chloride
(Ethoquad 0/12 - Armak) form a good base for alternative formulas.
In some cases, up to 6.0% ethanol may be added.
Continued
47
I
-------
TABLE 10. (Continued)
Formula I
Mousse Curl Activator
Ingredients % (v/v)
Propylene Glycol 32.00
Isodecyl Oleate or Myristyl Myristate 4.00
C12-C15 Alcohols Lactate Ceraphyl 41 by Van Dyk & Co., Inc. 6.00
Glycerine 5.00
Quaternium-26 (Hydroxyethyl) Dimethyl (3-Mink animal oil 2.00
amidopropyl) Chlorides. Ceraphyl 65 by Van Dyk & Co., Inc.
Quaternium-22 3-(D-Gluconoyl-amino)-N-(2-hydroxyethyl)- 1.50
N,N-Dime thy1-1-propanam inium Chloride. Ceraphyl 60 by
Van Dyk & Co., Inc.
Dimethacone Polyol Silicone Fluid L-720 by Union Carbide Corp. 1.50
PEG-40 Stearate Polyethylene Glycol (40 mol) Mono-ester of 1.50
Stearic Acid
Cetyl Alcohol 0.50
Fragrance 0.25
Methyl p.Hydroxybenzoate Nipagin M by Nipa Laboratories, Ltd. 0.25
Deionized Water 40.50
Isobutane A-31 Phillips Petroleum Company (Propellant A-46) 0.75
Propane A-108 Phillips Petroleum Company (Propellant A-46) 4.25
Note: The propylene glycol and glycerine are hair curl activators', while
the Isodecyl Oleate and C12-C15 Alcohols Lactate are glossing
agents. The Quaternium 22 is an optional agent, used to increase
humectancy and conditioning.
48
-------
Four products were presented, with SPFs (Sun Protection Factors) of 2, 4, 6,
and 12. For example, a product with an SPF of 12 will enable the user to
remain in the sun twelve times as long as the standard period required to
develop slight redness, while developing the same degree of coloration.
Since 1984, a number of relatively low-sales-volume sun screen mousse
formulas have been launched. Some are identified as "sun screens;" others are
labeled "sun and sport styling mousses" or other, less definitive names.
Table 11 lists the ingredients of two strengths of typical sunscreen mousses.
Sun protection formulations with SPF values of 15 to 20 (the practical
maximum) are often called sun-blocks (see Formula J in Table 11). They
require combinations of sun-screen agents of the oil- and water-soluble type,
to get the best distribution on the skin. In some cases, rigorous pH control,
using buffering agents, is required. Concentrations of from 5.5 to 10.0% are
required, depending on the efficiency of the screening agents, type of mousse
emulsion, distribution on the skin, repeat applications, skin condition and
moisture content, individual sensitivity, skin color, season, time of day,
elevation, geographic latitude, type of activities, perspiration rate, product
application thickness, etc.
For most people, a lesser degree of protection is acceptable. For those
spending two or three hours in the sun at one time, the use of products with
an SPF of about 4 to 6 is satisfactory. These products also permit the
development of a tan, which is often socially important to those people or
races having light-colored skin pigmentation.
Formula K, shown in Table 11, provides this intermediate degree of sun
protection, based on the use of iso-amyl-p-methoxy-cinnaniate. This water-
insoluble material provides SPFs of 4 (at 2.8%), 6 (at 3.6%), 8 (at 4.5%), and
12 (at 7.5%). Thus, the formula can be adjusted to give whatever degree of
solar protection is desired.
49
-------
TABLE 11. SUNSCREEN MOUSSE FORMULATIONS
Formula J
Sunscreen Mousse (SFF About 15)
Ingredients % (v/w)
Isodecyl Oleate or Myristyl Myristate 6.00
Isodecyl Oleate is available from Van Dyk & Co., Inc.
as Ceraphyl 140-A.
Octyl Dimethyl FABA (formerly Padamate 2) 6.85
Ester of 2-Ethylhexy1 Alcohol & Dimethyl p.aminobenzoic
Acid
Escalol 507 by Van Dyk & Co., Inc.
Benzophenone-3 3.20
2 -Hydroxy-4-me thoxybenzophenone
Uvinol M40 by BASF-Wyandotte Chemical Company
Stearic Acid 10.00
Octadeconoic Acid
Cetyl Alcohol 0.45
Hexadecyl Alcohol
Deionized Water 44.95
Hydroxypropyl Methylcellulose 0.55
Methocel F, by Dow Chemical Company, or Viscontran
MHFC by Henkel Chemical Company
Propylene Glycol 2.50
Triethanolamine 1.15
99% Triethanolamine by Union Carbide Corp.
Ethanol 18.00
Alcohol (Anhydrous Basis; Specially Denatured)
S.D. Alcohol 40 by U.S. Industrial Chemicals Division
Continued
50
-------
TABLE 11. (Continued)
Formula J (Continued)
Ingredients ' ; % (w/w)
TEA Coco-Hydrolysed Animal Protein (and) Sorbitol 1.00
Triethanolamine Salt of the condensation product of
coconut acids and hydrolysed animal protein
Haypon 4CT by Stepan Chemical Company
Methyl p.Hydroxybenzoic Acid 0.15
Perfume 0.20
Isobutane 4.25
Propane 0.75
Formula K
Sunscreen Mousse (SPF About 6)
Ingredients , % (w/w)
Steareth-10 0,80
PEG Ether of Stearyl Alcohol; CH3(CH2)15CH2-
(OCH2CH2)10OH
Brij 76, by ICI Americas, Inc.
PEG 150 Distearate 0.60
Polyethylene Glycol (150) Diester of Stearic Acid
Kessco X-211 by Armak Chemical Company, or Witconol
L32-45 by Witco Organics Division.
Sodium Hyaluronate 0.10
Sodium hyaluronate - high-molecular-weight polymer
from animal protein (90% powder) by Tri-K Industries,
Inc. (Reseller for Canadian Packers, Ltd.)
DMDM Hydantoin 1.10
1, 3-Dimethylol*- 5, 5-Dimethyl Hydantoin
Dantoin DHDMH-55 (or Glydant) by Glyco Products, Inc.
Continued
51
-------
TABLE 11. (Continued)
Formula K (Continued")
Ingredients . ; % (w/w)
Quaterniura 52 8.50
Dibutyl Sebacate
Dehyquart SP, by Henkel Chemical Co.
Isoamyl Methoxycinnaraate (CTFA) (FDA is pending) 3.60
Isoamyl-p-methoxycinnamate (98% min.)
Neo-Heliopan E1000 by Haarmann & Reimer Japan K.K.
Cyclomethicone - 2,50
Cyclic dimethylpoly (3 - 4) siloxane
Silicone #344 .Fluid by Dow-Corning Corporation
Dimethacone Copolyol (Water Soluble) 0.25
Dimethylsiloxane, end-blocked with surfactant groups
Silicone #193 Surfactant by Dow-Corning Corporation
Polysorbate 80 0.15
Mixed oleate esters of sorbitol and sorbitol anhydride;
mostly the monoesters, with 20 moles of ethylene oxide
Tween 80 by ICI Americas, Inc.
Polysorbate 20 0.40
Mixed laurate esters of sorbitol and sorbitol anhydride;
mainly the monoesters, condensed with about 30 moles of
ethylene oxide.
Nikko TL10 or TL-10EX by Nikko Chemicals, Ltd. or
Tween 20 by ICI Americas, Inc.
Olealkonium Chloride 0.10
Qleyl-dimethyl-benzyl-ammonium Chloride
Ammonyx K? by the Onyx Unit of Stepan Chemical Co.
Continued
52
-------
TABLE 11. (Continued)
Formula K (Continued)
Ingredients , , - % fw/w)
Nonoxynol-20 0.10
Ethoxylated (20)-p-n.nonylphenol
Igepal C0-850 by GAF Corporation, or Tergitol NPX
by Union Carbide Corporation
Aloe Vera 0.10
Aloe Vera Extract - 100% Pure (90% A.I. Powder)
Aloe Vera 100% by the Terry Corporation
Perfume 0.30
Methylchlorisothiazolinone, and Methylisothiazolinone 0.10
Kathon CG by Rohm & Haas Company
•Hydrofluorocarbon 152 4.00
1,1-Difluoroethane
Dymel 152 by E.I. DuPont de Nemours & Company, Inc.
Isobutane 2.00
Isobutane A-31 by Phillips Petroleum Company
53
-------
The mousse presentation can also be used, for baby care products.' They
avoid the spillage and application problems of other formulations. Table 12
lists the ingredients of these formulations.
Other commercial mousse products.include a facial cleansing preparation,
based on very mild surfactants such, as disodium cocoajnido MIPA sulfosuccinate
and sodiuun laureth sulfate, including Quaternium-22 to provide conditioning
and eraolliency. A facial makeup mousse uses a triethanolamine stearate and
PEG-20 stearate emulsifier combination to spread a combination of pigments1 and
emollients on the face to give an elegant matte finish. Hand creams are also
available, again based on triethanolamine stearate and PEG fatty acid conden-
sates as the emulsifier. Glycerin (5%) is included as a humectant. More
recently, a cationic skin mousse has appeared that includes mink (animal)
amidopropyl dimethylamine to provide'a unique lubricity and skin feel.
Several more interesting products are under intensive development.
The vaginal contraceptive foam is a product in the drug category that
depends on foam stability and density. The preferred active ingredient is
Nonoxynol 9, or nonyl-phenoxypolyoxyethylene ethanol. The formula for a
mousse product of this type has been published, and a variation is presented
as Formula N in Table 13.
Commercial formulas in the U.S. range from 8-12.51 of Nonoxynol 9, and
all the aerosols are pressurized with about 8% of a blend of GFG-12 and GFG-
114. An Amended New Drug Application (to the FDA) will be required before the
propellant can be changed to hydrocarbon or other types. This process takes
the FDA about 3 to 5 years to complete, since the entire NDA file must be
reviewed whenever a change is made.
A mousse product is also available for the treatment of mastitis infec-
tions in the udder of cows. An example is presented in Table 14.
A similar formula, based on the use of Procaine Penicillin G, represents
an anhydrous mousse system. Both formulas are designed for injection into the
udder via the sphincter canals. GFG-12 and CFG-11^ .are used for the products
54
-------
TABLE 12. BABY CARE MOUSSE FORMULATIONS
Formula L
Babv Oil Mousse
Ingredients
Deionized Water
Mineral Oil - Medium Viscosity
Cetaryl Alcohol (and) Cetareth-20
C16-C18 Alcohols and C16-C18 Alcohol PEG 20 Ethers
Macol 124 by the Mazer Chemical Company
Isodecyl Oleate and/or Myristyl Myristate
Ceraphyl 140-A and/or Ceraphyl 424 by Van Dyk & Co., Inc.
Cyclomethicone
Cyclic dimethylpoly (3-4) Siloxane
Silicone #344 Fluid by Dow-Corning Corporation
Ethanol
S.D. Alcohol 40 (Anhydrous)
S.D. Alcohol 40 (200°) by U.S. Industrial Chemical Div.
Aloe Vera
Aloe Vera Extract' - 100% Pure (90% A.I, Powder)
Aloe Vera 100% by the Terry Corporation
Perfume
Perfume selected for mildness
Methyl p.Hydroxybenzoate
Nipagin M by Nipa Laboratories, Ltd.
Hydrofluorocarbon 152
1,1-Difluoroethane
Dymel 152 by E.I. DuPont de Nemours & Co., Inc.
Isobutane
Isobutane A-31 by Phillips Petroleum Company
t (w/w)
23.00
30.00
10.00
10.00
3.35
12.00
0.25
0.25
0.15
8.00
3.00
Continued
55
-------
TABLE 12, (Continued)
Formula M
Babv Powder Mousse
Ingredients % (v/v)
Deionized Water 35.70
Silica (Powder) 0.30
Hi-Sil 233 Fumed Silica Anticaking Agent by PPG
Industries, Inc.
Quaternium-26 2.00
(Hydroxyethyl)Dimethyl(3-Mink Animal Oil Amidopropyl)
Chlorides
Ceraphyl 65 by Van Dyk and Company, Inc.
PPG Laneth 50 - 0.50
Polyoxyethylene (50) polycxypropylene (12) Lanolin Ether
Solulan by Amerchol Products Unit
Cetyl Alcohol 0.40
Talc 18.10
Talcum Powder - Impalpable
Altaic 200
Ethanol 32,00
S.D. Alcohol 40 (Anhydrous)
S.D. Alcohol 40 (200°) by Shell Chemical Company
Perfume 0.20
Hydrofluorocarbon 152 8.00
1,1-Difluoroethane
Dymel 152 by E.I. DuPont de Nemours & Co., Inc.
Isobutane 2.80
Isobutane A-31 by Phillips Petroleum Company
56
-------
TABLE 13. VAGINAL CONTRACEPTIVE MOUSSE
Formula N
Ingredients % Cw/w")
Nonoxynol 9 8,0
Lauric/Myristic Acids 2.5
Stearic/Palmitie Acids 3.5
Triethanolamine 2.2
Glyceryl Monostearatea 2.5
Polyoxyethylene (20) Sorbitan Mono-oleate 2.5
Polyoxyethylene (20) Sorbitan Monolaurate 3.5
Polyethylene 600 Glycolb 1.5
Polyvinylpyrrolidone K-30c 1.0
Benzethonium Chloride, USPd 0.2
Deionized Water 67.6
Propellant A-46 5.0
aViscosity builder and foam stabilizer.
bAverage molecular weight is about 600,
Protective colloid.
dBenzyldimethyl [2-[2-(p.1,1,3,3-tetramethylbutylphenoxy)ethoxy]ethyl]
Ammonium Chloride
57
-------
TABLE 14. MOUSSE FOR MASTITIS TREATMENT
Formula 0 ¦.
Ingredients ^ % (w/w)
Sodiuin Lauryl Sulfate (30% Active Ingredient in Water) 1 27.7
(As Duponol WA Paste, or equivalent)
Polyethyleneglycol 400 Distearate 3.5
Triton X-1001 0.4
Sodium Palmitate/Stearate 0.4
Sodium Sulfate 10-Hydrate 0.2
Sodium Citrate H-Hydrate* 1.5
Neomycin Sulfate (as base) 3.8
Sodium Hydroxide (50% in Water) -- to pH 9.2 q. s /
Deionized Water 56.5
Propellant A-46 6.0
"Foam modifier.
'"Sequestrarit and stabilizer.
CA sufficient quantity.
58
-------
available in the U.S., but an interesting topical product, using dimethyl
ether as the propellant was patented about 1984. It contains chlorhexidene
acetate or gluconate plus a light-blue dye (to show the areas treated), in a
hydroalcoholic system, After mxlkxng, xt xs used as a germxcxde and the
chilling effect of evaporating diethyl ether causes the sphincter muscle to
immediately close, preventing contamination of the udder quadrants and
incidentally also preventing some leakage of milk. The product is especially
useful for older cows on automatic milking machines.
Pharmaceutical foams have been well received for over a dozen specific
applications, including hemorrhoid treatment, relief of tenesmus in deep
wounds and ear cleansing.
When foam medicinals are to be inserted into various body cavities, it is
often best to use a special type of very blunt, all-plastic syringe, such as
the model shown in Figure 1.
PLUNGER, OR
PISTON
OR
CYLINDER
_n
NOZZLE
5 OR 10 mL MARK
Figure 1. Foam Syringe
Directions: To use the metering syringe, fill the barrel with foam to a level
beyond the volume mark, minimizing any air pockets. Press the piston in until
it reaches the volume mark, removing excess from the nozzle tip. Insert; then
slowly press the piston in to the fullest extent. The narrow tip of the
plunger serves to minimize any wasted product remaining in the nozzle area,
since such medications are often rather costly.
59
-------
Since dosage is directly affected by foam density, it is desirable to
formulate a foam with a density in the range of 0.05 to 0.10 g/raL, using
sufficient propellant so that the foam density at the beginning of product use
will not be more than 25% less than that near the end. Uniformity of propel-
lant fill is also very important. For example, a Pantasol "Stepped Rotary"
filler contains two concentrate filler heads, a crimper, and two propellant
filling heads. It will-produce 35-40 meter-spray cans per minute, or 60-70
regular cans per minute, filling both product and propellant with good
accuracy. It is the filler of choice (worldwide) for small, pharmaceutical
products.
Shave Creams
Shaving creams--the last of the "mousse" products to be discussed--are
more of a utility product than a personal care item. In the U.S., a 310-g
dispenser can still be purchased on sale for less than $1.00, although most of
the name-brand shave creams cost at least twice that much.
Discovered in 1931 by Eric Andreas Rotheim of Norway, who pressurized
certain soap solutions with butanes, the shave cream was reborn in the U.S. in
1948. It used from 6.5 to 8.5% of a CFC-12/114 blend. In 1954, all but one
marketer changed over to 3.4 to 4.0% Propellant A-46. This particular blend
of propane and isobutane has air-free pressures of 3.24 + 0.14 bar at 21°C,
and 8.87 + 0.35 bar at 54.4°C. At the time of its first production, it was
the highest-pressure mixture that could be used for atmospherically crimped,
standard-strength aerosol cans. Table 15 gives the formulations for three
typical shave creams.
The usual shave cream formula is an 8 to 12% dispersion of sodium or
potassium and triethanolamine fatty acid soaps in water, plus foam stabili-
zers, wetting agents, emollients, humectants, fragrance, preservatives, and
sometimes special ingredients. Some fairly exotic materials have sometimes
been used, such as fluoro-aerylic "super-detergents" for extra beard soften-
ing, and hyaluronic acid, a natural polymer that encourages the skin
60
-------
TABLE 15. SHAVE CREAMS
Ingredients
Formula
A
Formula
B
Formula
€
U.S. Tradenames
Deionized Water
74.9
79.5
78.1
Lauric/Xyristic Acids
1.5
1.0
0.7
Emersol 132 , el.al.
Stearic Acid (Triple X)
6.0
7.0
8.0
Emersol 655 or 621
Lauryl/Myristyl Diethan-
olamine
0.5
2.0
Schercomid SLM-S
Sodium Lauryl'Sulfate
(302 Water Solution)
1.5
Duponol WAT 30%
Sodium Hydroxide (50%)
0.5
Dow Chemical Co.
Potassium Hydroxide (45%)
2.25
0.4
Triethanolamine (99%)
Cetyl Alcohol, N.F.
3.9
0.5
_ - - _
3.0
Union Carbide
Corp.
Glycerin - 96%, U.S.P.
5.8
4.0
2.5
Polyvinylpyrrolidone K30
0.15
Mineral Oil, N.F. Grade
2.4
Witco "Carnation"
Me thyl p.Hydroxybenzoate
0.1
0.1
n. Propyl p.Hydroxybenzoate
0.03
0.04
Fragrance
0.67
0.3
0.36
IFF #2651-AB
Lanolin Derivative
' 0.5
0.2
2.0
Lantrol-Malmstrom
Propellant A-46
' 3.2
3.1
3.3
Phillips Petroleum
Note: These formulas may be packaged in tinplate or aluminum single-lined
cans.
61
-------
renewal process and moisturizes the skin, to reduce the irritation of close
shaving.
Formula A is the highest quality of the three, followed by Formula C.
Formula A is also the most costly, but the marketer has the option of making
such claims as "sodium free," "contains no alkali," or "100% organic," which
may be advantageous.
In addition to the foam stability provided by the sodium lauryl sulfate
(often called SLS), PVP K30, lauryl/myristyl diethanolaraide (or coco-dietha-
nolamide), and especially cetyl alcohol, formulation chemists may use Keltrol
or Methocel 25M.C thickeners, Monamld 150LW, Deriphat 170-C (acid zwitterion)
and other ingredients. The critical test for sufficient foam stability is
that the foam should not significantly drain or dry out from below the nose of
the user in less than three to four minutes, even at low humidities. It
should also be stiff, smooth and thick-textured, and form a 5-g puff able to
support a full-length pencil at a 5° angle. Some foams are dispensed hot,
either using reactive chemicals (such as sodium thiosulfate and 10% hydrogen
peroxide, kept separate until the moment of use), or more commonly by using an
electrical heating mantle. In such cases, the foam may be delivered "steaming
hot" at up to 85°C, and quite a lot of extra foam stability agent will be
required. These hot foams represent only about 4% of the 210,000,000-unit
U.S. aerosol shave cream market.
The choice of propellant is critical to success. At pressures of 2.5 bar
or less at 21°C, a secondary expansion will occur in the hand, which is
perplexing to the user. Blends higher in pressure than Propellant A-46 will
normally require a special, high-pressure-resistant can.
The amount of propellant is also important to success. The use of too
little propellant results in production of a higher density foam (such as
0.12 g/mL), and the situation will worsen as the dispenser is used up. This
is because emulsified propellant can escape into the expanding head space,
leaving less in the liquid phase to produce the foam structure. Conversely,
over 4.OX hydrocarbon propellant will produce a relatively dry, airy foam with
-------
poor wetability and smooth-out properties. Excessive propellant may escape
during actuation, leaving the foam puff defaced, with a pock-marked, wrinkled
or roughened surface, The noisb level will he higher as the propellant tears
the foam micro-structure during the escape process.
Some work has been done with alternative propellants, Those with both
oil and some water solubility produce less stable foams, such as HFC-152a, but
the stability may be adjusted by using blends of HFC-152a and hydrocarbon
propellant. Dimethyl ether "will not produce a foam. Nitrous oxide generates
satiny foams with very fine micelle structures, as does carbon dioxide.
Despite the low solubility (about 1%), these foams remain reasonably uniform
throughout package life, especially if only 60-65% product is placed in the
can.
Many unusual foams have been produced. There are exploding foams,
bouncing types, crackling foams, and even anhydrous foams of astonishing
durability. Several anhydrous types are used for the application of topical
pharmaceuticals.
Several food foams have been introduced, but the only really successful
one is whipped cream, which is nearly always pressurized with approximately
1.2% nitrous oxide. The slow growth of psychrophilic bacteria, even at 2°C,
has posed a major shelf-life problem for many of these products. One U.S.
filler has developed a process for producing sterile products, but enzymes
will adversely affect even these products within a few months.
Whipped food products that have not been marketed to any extent are
pancakes (crepes), expanded mayonnaise, whipped syrups, ice cream toppings,
chocolate milk additives, and alcoholic toppings for Irish Coffee and certain
mixed drinks. In the U.S., the hydrocarbon propellants, nitrous oxide, carbon
dioxide, and nitrogen, are the only propellants permitted for food uses. In
some other countries,, nitrous oxide is not allowed in food products. One of
the key problems with food aerosols is that the final dispensers cannot be
autoclaved to render the contents sterile without causing the cans to burst.
63
i
-------
Underarm Products
In the U.S., these aerosol products fall into two distinct classes: the
antiperspirant and the deodorant. Antiperspirants are considered drug
products by the U.S. Food and Drug Administration because they have a definite
physiological effect on the pores of the skin, and they are regulated accord-
ingly. On the other hand, a simple deodorant consists of an alcoholic
solution of a germicide, which does nothing except to reduce the population of
skin resident bacteria for several hours, thus inhibiting their ability to
degrade certain ingredients in natural perspiration into malodorous materials.
Antiperspirants also function as deodorants, because they reduce the pH value
of the skin to about 3.2 to 4,2 at 35°C, and this level of acidity inhibits
the proliferation of microorganisms.
In the U.S., an aerosol antiperspirant must, by definition, act to reduce
the rate of perspiration. More specifically, antiperspirants must reduce the
output of the apocrine sweat glands by twenty to seventy per cent. These
glands are actually located not only at the armpits, but in the ano-genital
area, the eyebrows, and (in women) behind the ears. Despite the commer-
cialization of aerosol antiperspirants in the past for more general body
application, currently available products are labeled for underarm use only.
All antiperspirants have a physiological effect on the skin, but these
effects vary widely with the formula, the consumer, testing conditions, time,
and other factors. Sweat reductions even between the right and left underarm
areas of a given person may be quite different. In 1978, the FDA issued a set
of OTC (Over-The-Counter) drug regulations for antiperspirants, titled
"Guidelines For Effective Testing of OTC Antiperspirants" that defined an
axillary sweat reduction study (2) as a proposed Monograph. It stipulated
that an aerosol antiperspirant must reduce sweat by at least 20% after both 1
hour and 24 hours from the time of application in at least 50% of a minimum
15-person target population. The test conditions were 38°C and 35% RH
(Relative Humidity) during the one-hour collection periods for each day of the
five-day test cycle, and 22.2"C otherwise. Application time was described as
a two-second spray under each arm.
64
-------
Until the introduction of the more powerful aluminum chlorohydrate
complexes in 1986, most aerosol antiperspirants fell into the 22-33% sweat
reduction category. By comparison, stick antiperspirants exceed 40% and some
roll-ons reach 65%. However, a sweat reduction of 25% or more represents such
a dramatic improvement in the control of wetness that many users are quite
satisfied with aerosol performance. During the recent introduction of the
new, more potent antiperspirant materials, however, the suppliers stated that
they made these changes because of some user dissatisfaction with product
effectiveness, resulting in a sales reduction of the aerosol category over the
years. Aerosol antiperspirants have also had modest problems with "bounce
off," resulting in some nasal irritation, higher packaging costs, and occa-
sional valve plugging. Recent attempts to reduce ground-level ozone (smog-
related) have caused at least one state to study aerosol VOC emissions.
During 1985, the Reheis Chemical Company (U.S.) announced their new line
of REACH antiperspirants for aerosols and other dispensing forms'. These are
up to 50% more potent than the standard aluminum chlorohydrate complex; e.g.,
[Al2(0H)s] 13«2. 5H20--which has an Al;Cl ratio between 2.1 and 1.9 to 1.0, and
an FDA permit level of up to 25% of the total product.
The new REACH 101, 201, and 501 compositions represent commercial forms
of aluminum chlorohydrate polymer that can be separated out of the mixture of
polymers in the parent compound using liquid chromatography. The A1:C1 ratio
is maintained. With the greater effectiveness (up 30 to 50%, depending on
choice) formulators had the following options:
¦ Use the new compounds at the former levels, for a 30 to 50% more
effective product; or
• Use reduced concentrations of the new compound, lowering the
effectiveness of the product to the former level, but reducing
formula cost and bounce off.
65
1
-------
Table 16 compares some representative antiperspirant product efficien-
cies .
In one form or another, aluminum chlorohydrate is the only active
material now used in aerosol products, but the specific polymeric compositions
and their particle size distributions have gone through a transition from 1986
through 1989 that now suggest that the REACH compounds have captured at least
802 of the U.S. market volume. In 1988, the aerosol underarm products sold
increased from 114 million units to 144 million, or 26X, although the aerosol
industry grew by a comparatively small 6.8 percent. This extraordinary growth
is said to have been the result of the availability of more effective products
and well-advertised introductions by Mennen, Bristol-Myers, and other mar-
keters. The aerosol share of the underarm market also grew, from 31% to 37%.
The present products contain from 7.0 to 12.5% of various aluminum
chlorohydrate complexes. Without the addition of a dispersing system, the
suspended aluminum chlorohydrate would settle into a bottom layer between uses
and would require long and difficult shaking to redisperse. Also, the
material within the very bottom of the dip tube will not redisperse even with
shaking, leading to valve plugging and consumer dissatisfaction. Because of
this, all aerosol antiperspirant formulas contain a dispersing agent, normally
a surface-treated form of montmorrillonite clay activated by the inclusion of
a relatively polar ingredient such as ethyl carbonate or ethanol. With the
correct combinations and balances and good compounding techniques, clogging
problems can be avoided.
Table 17 presents the formulation of a low-cost, low "bounce off"
antiperspirant of above average effectiveness.
Both the isopropyl myristate and silicone fluids of the formula shown in
Table 17 are useful as inert carriers to transport the aluminum chlorohydrate
to the skin surface and stick it there with a minimum of bounce off. These
ingredients are also needed as slurrying material for the aluminum chlorohy-
drate to facilitate the production process.
-------
TABLE 16. COMPARISON OF ANTIPERSPIRANT EFFICIENCIES
% Efficiency
Generalized Composition and Form First Day Fourth Day
3.5% Old CFC Formula (Banned in 1978) 25
10.0% Hydrocarbon-Type Aerosol 25 + 7 29+7
12.5% Hydrocarbon-Type Aerosol 30
10.0% Hydrocarbon-Type Aerosol (REACH 101) 44 + 8 57+6
10.0% Hydrocarbon-Type Aerosol (REACH 201) 38+8 50+9
10.0% Hydrocarbon-Type Aerosol (REACH 501) 35+7 45+10
20.0% Suspension Stick - Standard 40
20.0% Suspension Stick - Rezal 36GP Active 55
25.0% Roll-On Suspension - REACH AZP-703 62
67
-------
TABLE 17. AEROSOL ANTIPERSPIRANT
InEredients
% (w/w)
Aluminum Chlorohydrate (REACH 101)*
8.00
Quaternium 18 Hectorite (Bentonite 38)b
0,82
S.D. Alcohol 40-2 (Anhydrous)
0.80
Dimethylsilicone [500 centistokes (cstks)]c
1. 50
Isopropyl Myristated
1.00
Cyclomethicone F-251*
7.63
Perfume 0ilf
0.25
Propellant A-31 or A-468
80.00
aREACH 101 is produced by the Reheis Chemical Company, 235 Snyder Avenue,
Berkeley Heights, NJ. (201)464- 1500. (An equivalent product is produced by
the Wickhen Division of the Dow-Corning Corporation.)
bBentonite 38 is a surface quaternized form of montmorillonite clay, offered
by NL Industries, Inc. as "Bentone 38."
cDimethylsilicone (500 cstks.) is available from Dow-Corning Corp., General
Electric Silicones Division, and others. Purchase the anhydrous (clear)
liquid, not the emulsion forms.
dIsopropyl Myristate is sold by "Van Dyk & Co., Inc. and many other firms.
aCyclomethicone F-251 is a physical mixture of Cyclomethicone D-4 Tetranier
25%, and Cyclomethicone D-5 Pentamer 75%. It is available from the Dow-
Corning Corp.
fThe perfume oil is the marketer's choice. It must be purchased from a
perfume house that is advised that it will be used in a REACH 101 aerosol
antiperspirant, and then tested for compatibility with the product. The
percentage may vary, according to fragrance intensity and the marketer's
preference.
8Propellant A-31 (with vacuum crimp) is preferred, giving a can pressure of
about 2.5 bar at 21.1"C. The use of Propellant A-46 will provide an initial
pressure of about 3.6 bar at 21.1"C (with vacuum crimp) and thus a delivery
rate approximately 19% faster at the beginning of use. Preferential removal
of air and propane through the vapor-tap orifice will reduce pressure to
about 2.6 bar at 21,1°C when the dispenser is 50% empty, and to about 2.3
bar at 21.1°C at the point of incipient emptiness.
(Continued)
68
-------
TABLE 17. (Continued)
Notes:
1. Concentrate Viscosity; 18,000 cps. (Brookfield Viscometer; 10 rpra.)
2. Concentrate pH Value: 3.3 - 4.7 (1:10 v. dilution in deionized water)
3. Concentrate must be homogenized to remove probable clumps or clusters of
oil-wetted aluminum chlorohydrate powder.
4. REACH 101 is hygroscopic and must be protected from the moisture in
ambient air at all times. Once it is added to the oily concentrate it
will no longer absorb moisture. The following recommendations apply:
• Keep drums closed except when sampling or using;
• Do not remove packets of moisture-absorbent silica gel in
drums, if present, except when adding REACH 101 to batch;
• Add REACH 101 as quickly as practical, while still minimizing
clumping; and
• Rinse off tank walls of REACH 101 powder, immediately after
addition.
5. If a U-t-C (Under-the-Cap) gasser is used, the last 10% of the propellant
must be added by means of a following T-t-V (Through-the-Valve) gasser in
order to clear thick concentrate from the dip tube and avoid possible
valve-plugging problems.
6. All equipment touching the concentrate should be of 304 or 316 stainless
steel, Tygon® hose, or approved rubber hoses in good condition.
7. The concentrate is sufficiently thick or viscous that settling of the
solids will be a slow process. However, continuous recycling of the
concentrate is -required, as well as some slow stirring of the concentrate
filler bowl. Over-circulation, such as short-loop circulation during
filler downtimes, is not recommended. It may cause localized heating and
micro-splintering of the solid aluminum chlorohydrate.
69
-------
The isopropyl myristate improves feel (or handle) and texture. Being
essentially nonvolatile, it helps the Dimethylsilicone (500 cstks.) carrier
keep the underarm area lubricated for many hours.
The other silicone materials are relatively volatile. The F-251 blend is
selected for a combination of effectiveness and lower expense. They are used
to impart an extra measure of carrying ability and skin lubricity, preventing-
any tackiness development as the aluminum chlorohydrate slowly dissolves in
perspiration films. Having done their work, they slowly evaporate, preventing
long-term excessive oiliness and the staining of clothing in the underarm
area.
The isopropyl myristate, and various silicone fluids also help the
operation of the aerosol powder valve. They reduce the amount of bulking
agent needed to prevent hard-packing of solids between product applications.
Finally, they provide spreading characteristics that help distribute the
aluminum chlorohydrate more effectively across the dermal surface.
If excessive amounts are used, the oil may coat the aluminum, chlorohy-
drate so effectively that it cannot contact skin moisture and begin dissolv-
ing, This will cause a lag between the time of application and the time
antiperspirancy becomes apparent. Fabric staining, "wetness," and cost will
all increase if too much isopropyl alcohol and silicone fluids are used.
Other materials have been suggested as replacements for these ingredi-
ents. For example, Croda, Inc. suggests replacing isopropyl myristate with
their Frocetyl AWS (a propoxylated/ethoxylated ether of cetyl alcohol).
Union Carbide suggests using Fluid AP, and others have promoted such items as
myristyl myristate ester and octyl palmitate ester. Such ingredients are
added at some risk. For example, some samples of myristyl myristate contain
small amounts of unreacted myristic acid, which can seriously reduce or even
eliminate the antiperspirancy of the aluminum chlorohydrate.
The Bentone 38 surface-polarized montmorillonite clay is very finely
divided and has the approximate formula NaCa[(Al,Mg)2Si4O10]*Q*nH20. where Q is
70
-------
a specific quaternary ammonium compound designed to increase surface charge
and further promote suspending properties, A small amount of ethanol is added
to activate the polar surface and augment charge separation.
When the balance is achieved, the Bentone 38 and ethanol system will slow-
down the settling of the aluminum chlorohydrate and allow it to eventually
settle into a lose, voluminous layer between product uses. A gentle inversion
or shake will then swirl the solids back into suspension. This should be
checked for any new formula (even a new perfume in a tested formula) using
glass compatibility equipment. If the aluminum salts can settle into a hard,
obdurate mass--regardless of settling rate - - the product will suffer from
problems of reconstitution and probable valve plugging.
Both scented and unscented antiperspirants are marketed. The unscented
versions are sometimes preferred by men, and always by hypoallergenie persons.
They are usually very lightly scented, despite the label, using approximately
0.04% of nondescript perfume oils to cover the slight chemical odors of the
other ingredients. Some products contain encapsulated perfumes, in addition
to the "non-encap" perfume. They provide longer-term fragrance release, as
moisture dissolves the modified polyvinyl alcohol (0.001"(0,025mm)-diameter)
micro-capsules of additional fragrance.
The aluminum chlorohydrate easily develops enough acidity under the arm
to prevent the proliferation of skin-resident, odor-causing bacteria. Thus,
no special microbicides need be added, except to treat cases of chronic
hyperhydrosis or certain other dermal pseudomorphoses,
The horaogenization step for the concentrate-processing stage should be a
one-stage, rather gentle one designed to break up clusters of, oil-saturated
aluminum chlorohydrate, rather than to fracture the roundels of the salt
itself.
The roundels are already sufficiently fine-particled that they will not
clog an aerosol valve. But if they are broken up Into a lot of "splinters,"
buildup and possible clogging might occur.
71
-------
Sample amounts of the concentrate should be made dn the laboratory so
that the viscosity and flow characteristics of the batch-making process can be
considered. A variable speed, planetary, top-entering agitation system is
needed for best results. When the powder is added and viscosity increases,
all parts of the mixture must be agitated.
The compounding procedure is as follows:
• Add the isopropyl myristate, through a 5-micron filter;
• Add the Cyclomethicone F-251, through a 60- to 100-mesh screen;
• Begin agitation at about 75 rpm;
• Begin recycling, out the bottom and back into the tank via a pipe
that extends to the lower one-third, to prevent splashing. The pump
in this system should be set at around 150 to 200 rpm to prevent
shearing. A Cuno or similar filter in this line will be bypassed
during the compounding stages;
• Pre-weigh the Bentone 38 and add manually to the tank at a fairly
slow rate, about one 20-kg bag per minute at most;
• Agitate at least 15 minutes, until the Bentone 38 is dispersed;
• Add the SD Alcohol 40-2 (Anhydrous);
• Operators in face masks and protective clothing then add powdered
aluminum chlorohydrate REACH 101 to the mix-tank at a rate of about
25 to 50 kgs per minute:
Build batch size around full-drum amounts of REACH 101 if
possible, to prevent dealing with partial drums,
72
-------
Protective masks and clothing are needed because of the genera-
tion of irritating dusts during additions;
• Rather quickly, add the dimethylsilicone (500 cstks) to the batch
tank, using a suitable Tygon or rubber hose, so that deposited
powder on the walls and dome of the mix-tank can be rinsed down into
the" batch;
• Add Perfume Oil;
• Agitate at least 15 minutes. Check for dispersion uniformity;
• Arrange recycling line to pass product through stainless steel Cuno
filter (coarse) and through either a Votator or Homogenizer to
homogenize the lumps. Use a filter with about 0.13-mm spacings.
Use a flow rate of 150 to 200 kg per minute;
• Pass the finished concentrate into a stainless steel, agitated
holding tank, with a recycling line as close to the concentrate
filler as practical. The temperature will have increased some 5° to
10*C during rotating or homogenizing, but it should not be allowed
to be over 40°C.
The valve is often supplied by Precision, Seaquist, Valois, Aeroval,
Summit, or other major- manufacturers in a rounded edge, powder-valve design.
In the U.S., a large, 20-mnt diameter, white, one-piece button is used. It is
ordered separately from the valve and applied by hand (rarely) or by an
automatic button tipper, often to line up with the 180° reverse-directional
dot on the crown of the valve cup.
A prototype valve is one with a 0.46-mm stem orifice, 0.63 x 0.46-mm
vapor-tap body, neoprene gasket, and 0.50-mm straight-bore actuator button.
The delivery rate can be changed downward if desired by using a 0.50-mm vapor -
tap orifice instead of the 0.46-mm size. Many formulators check several
larger-volume products on the market and decide which ones have the best spray
73
-------
pattern, delivery rate, and other characteristics they require. They then •
contact the appropriate valve company, identifying the product, and ask for a
sample valve made to the same specifications. Unless it is a customized
component (which is rare, except perhaps for color) the valve-maker will
always comply.
Two forms of the REACH 101 antiperspirant powder, differing only in
particle size distribution, have been used in aerosols:
• MICRO-DRY "REACH 101" (Reheis): Standard. Impalpable. More than
99.8% of the particles are smaller than 74/j;
• MICRO-DRY "REACH 101" (Reheis); Ultrafine. At least 99.8% of the
particles are smaller than 50/i.
A filtration step, using a Cuno or equivalent cartridge filter of 0.13-mm
retention, removes agglomerates, oversized particles, tramp cellulose fibers
(from bags), and other extraneous solids from the finished batch of concen-
trate. Experience suggests that the Standard, Impalpable grade is quite
satisfactory and somewhat less of a potential problem in terms of the rate of
moisture pickup during handling. However, it is always a good idea to contact
the suppliers (Reheis and Dow-Corning Corporation, in the U.S.) and ask for
recommendations and literature.
The aerosol can may be a necked-in 200-201/202x406 or 509 or 514-mm can
in the U.S. market, which is equivalent to a 51-51/52x111 or 140 or 148-mm can
elsewhere. The necked-in version is a marketer preference, based mainly on
aesthetics, not on technical or functional requirements. The so-called
"straight-wall" cans are also acceptable. Because the low-density hydrocarbon
propellants are nearly always used at levels approximating 75%, it is
customary to place a 100-to 115-gram fill weight into the can size just
described.
In the U.S., the necked-in cans have a 50.70 + 0,25-mm industry specifi-
cation for the diameter of the top double seam. This relatively difficult
74
-------
specification reflects a need for uniformity to prevent full-diameter
straight-wall cover-caps from fitting too tightly or too loosely when applied
over the seam.
The cans are generally of minimal tinplate throughout, with a single
lining and usually a stripe over the welded side seam. Adherence to Good
Manufacturing Practices (GMP) , whi-ch includes code legibility, is a general
requirement for this Over-The-Counter drug product.
The personal deodorant (or underarm spray deodorant) complements the
antiperspirant. It is often used by those who have either constant or
sporadic skin irritation problems with antiperspirants because of their
salinity, astri'ngency or acidity, or by those for whom underarm perspiration
is either not a problem, or cannot be controlled by antiperspirants because of
the environment or type of activity.
The basic personal deodorant formula consists of a germicide, fragrance,
ethanol solvent, deionized water (sometimes) and propellant. The standard
propellant in the U.S. is either isobutane, or a mixture of up to 37 wt%
propane in isobutane. In Europe, both hydrocarbon and dimethyl ether pro-
pellants have been used. Various HFC and HCFC propellants could technically
be used, but their higher cost has so far effectively precluded their use.
Four representative formulations are given in Table 18,
The size of the personal deodorant market is now about 55,000,000 units
in the U.S., 34,700,000 in 1988 in Japan, and relatively small in Europe. The
containers are similar in size and logo to the antiperspirant aerosols, and
are sometimes purchased by mistake because of this. Most major marketers
offer both products in two or three sizes and in both scented and unscented
75
-------
TABLE 18. PERSONAL DEODORANTS
Ingredients
Formula
A
(%)
Formula
B
m
Formula
C
(%)
Formula
D
m
Irgasan DP-3000® Germicide
0.11
0.12
Genzthioniura Chloride6
0.20
Methyl p.Hydroxybenzoate
....
0.03
n.Propyl p.Hydroxybenzoate
0.06
Benzyl p.Hydroxybenzoate
¦
0.08
Propylene Glycol, U.S.P.
1.50
1.03
Dipropylene Glycol
1.05
2.00
Zinc Phenolsulfonatec
1.00
Fragrance
0.35
0.25
0.30
0.38
S.D. Alcohol 40-2•(Anhydrous)
58.00
68.50
63.50
13.35
Deionized Water
47.00
Sodium Benzoate
0.15
Isobutane (A-31)
40.00
....
Propellant Blend A-46
16 wt% Propane in Isobutane
35.00
Propellant Blend A-70
37 wt% Propane in Isobutane
30.00
Dimethyl Ether
36.00
a2,4,4'-Trichloro-2'-hydroxydiphenylether.
bBenzyldimethyl *2-[2-(p.l,l,3,3-tetramethylbutylphenoxy)ethoxy]ethyl]
Ammonium Chloride.
sZinc Sulfocarbolate.
76
-------
versions. The packaging requirements for the hydrocarbon-propelled formulas
are designed to give a fairly fine-particled, low delivery rate spray, using a
vapor-tap valve with (typically) a 0.33-mm diameter orifice and a mechanical
break-up button. For the dimethyl ether products (as in Formula D of Table
18), very efficient valves are required to break up the large amount of water
present. The Precision Valve Corporation's 2 x 0.50-nro "Aquasol" stem valve,
0.50-mm MBST (Mechanical Break-Up, Straight Taper) button, and butyl rubber
stem gasket valve may be used. The supplier should be contacted for specific
recommendations, but sprays of 60n average particle size are obtainable. The
somewhat higher cost of dimethyl ether in most areas can be justified by its
ability to incorporate significant amounts of water in solution, giving the
feeling of excessive wetness. The flame projection of this formula will vary
somewhat with valve selection, but it is generally a 100- to 150-mm small,
sputtering light blue plume or flare.
Colognes and Perfumes
A cologne is generally considered to be a dilute form of the perfume or
sachet product, containing from 1.5 to 6.5% of essential oil or fragrance
compound. The true perfume may contain from 6.5 to 14.0 percent. The carrier
is almost always ethanol, generally anhydrous ethanol, and the propellent is
often a hydrocarbon type. For perfumes, which are smaller and more costly
than colognes, the glass or aluminum dispenser carries a meter-spray valve
able to dispense about 0.05 gram per actuation. A typical 20-gram fill will
offer about 400 actuations to the user.
The European innovation known as the deo-spray is a form of cologne and
has the typical cologne composition. No deodorant is present, as might be
inferred from the generic name. Packaged in lined aluminum cans holding as
much as 200 grams, the deo-spray or deo-cologne provides an inexpensive option
for spraying one's skirl or clothing with a relatively low-cost but still
acceptable fragrance. Some deo-sprays are made especially for use by younger
children and are labeled accordingly. Plastic caps resembling flowers and
animal heads have been used for added appeal. Finally, the sachet spray falls
somewhere between a cologne and a perfume. It contains approximately 4 to 8%
77
-------
fragrance compound formulated to as light a color as possible to prevent the
staining of lingerie, handkerchiefs, and other fabrics. Two typical cologne
formulas are presented in Table 19.
Glass has been the accepted standard for colognes since the origin of the
aerosol cologne in 1953. While plain glass containers of up to 125-mL
capacity have been marketed, glass bottles of greater than 30-raL capacity are
usually plastic coated. In the U.S., the Wheaton Aerosol Company's "Lamisol"
container is often used. It has a vinyl-based covering that firmly adheres to
the glass surface, making it more resistant to fracturing if dropped and
helping to contain glass fragments and flammable vapors if the container does
break. At present, the U.S. Department of Transportation limits the size of
non-metallic aerosol dispensers to a capacity of 118.3 mL (without a special
exemption).
The use of the OPET, Petasol, and similar plastic bottles is being
studied in the U.S., Japan, and Europe. Based on biaxially-oriented polyethy-
lene terephthalate, these bottles offer lightness, great break resistance,
clarity, translucency, or opacity, and more freedom of shape and design than
glass. Their very lightness has been viewed as a marketing deterrant, since
buyers are accustomed to the solidity and weightiness of glass as a quality
attribute. These bottles cannot be used for strong solvents, such as dimethyl
ether, since they lose strength rather rapidly at temperatures of over 60°C,
and may suffer from permeation effects when used with some formulations. In
England, hair sprays (not too different from many cologne formulas) have been
marketed successfully as 200-gram fills in OPET bottles.
The levels of HFC-152a (CH3*CHF2) or HCFC-22 (CHC1F2) used in Formula A
in Table 19 are considered minimum levels. The vapor pressures of both
propellants are suppressed when they are added to ethanol, an effect reduced
when water is incorporated as a third ingredient. This is why Formula A
contains 13% deionized water. An aerosol valve with maximum breakup power is
used for all cologne formulations.
78
-------
TABLE 19. COLOGNE FORMULATIONS
Ingredients
Formula A
m
Formula B
(%)
Fragrance
Di-n.butyl Phthaiate
Sodium Saccharinate0
FD&C and/or D&C Dye' Solution®3
S.D. Alcohol 40 or 39C
(Anhydrous)
Deionized Water
HFC-152a or HCFC-22
Isobutane A-31
Packaging mode:
4.00
2.00.
0.01
0.09
65.00
13,00
15.90
^5
4.00
76.00
20.00
Aluminum
aThe Sodium Saccarinate (or a similar synthetic sweetener) is added to nullify
the rather tart bouquet of the ethanol.
bIn the U.S., these are Food, Drug, and Cosmetic-approved dyes or Drug and
Cosmetic-approved dyes in the form of a stock solution of various
concentrations. The solvent is generally deionized water, but propylene
glycol and/or a preservative may be added as well.
79
-------
Perfumes, deo-sprays, sachets, and related products have relatively
similar formulations. Fragrance is deposited on an animate or inanimate
surface with high efficiency. The spray must be relatively wet, but still
retain cosmetic elegance.
Although dimethyl ether could be used in fragrance products, and there
are those who claim it imparts a cleaner, fresher odor, especially when water
is included, others suggest that the propellant itself has a stronger odor
than the purified hydrocarbons, and certainly much higher than HFC-152a, which
has almost no odor at all. Fillers in various parts of the world continue to
use CFC-12/114 blends for perfumes and colognes, partly because of the greater
importance of reduced final-product flarmnability when dealing with a frangible
material such as glass. Some of these fillers are not set up yet to safely
handle flammable propellants. In time, they will have the option of convert-
ing to nonflammable HCFC-22 propellant or to one of the nonflammable future
alternative types, such as HFC-134a. The latter is a modest solvent and is
virtually odorless.
Perfumes are extremely complex mixtures of both natural and synthetic
materials, and it is rare that all of them are soluble in the complete aerosol
formula. In some instances, these resinous substantives will only precipitate
after several days or weeks. When they do, they usually agglomerate into
fairly hard masses, readily capable of causing sputtering, distorted spray
patterns or even plugging the aerosol valve. In a clear glass container the
precipitation can be seen, and it gives a very negative image of product
quality.
An early industry practice was to store the complete formulation in a
covered 2,000-liter tank at -lO'C for several days, then to filter out the
dregs enroute to the product filler. With the flammable propellants, this
technique is no longer practical, although the complete concentrate can
certainly be held for a time at room temperature and then filtered free of
precipitates. The perfume suppliers are well aware of the problem and can
sometimes provide fragrances that have been tested to show that the addition
of hydrocarbon propellants to the filtered concentrate will not cause any
80
-------
further precipitation. The marketer should always make the "two-week test,"
which 1s to prepare the finished formula in exther a clear glass aerosol, or
in a clear glass product-compat ibi 1l. ty tube of about 100-mL capacity, holding
it for one week at 35 to 40°C, and then for one week at 2 to 4°C. The sample
unit is then evaluated for clarity or haziness, for precipitation, and for
good odorous stability when compared with a freshly prepared standard in
glass. The darker-colored fragrance products seem to be more prone to
precipitation.
When fragrance products are packaged in small aluminum cans, the cans
should be lined with an epon-phenolic or similar material. Otherwise, the
bare aluminum metal may have a reducing effect on aldehydes and certain other
sensitive perfume ingredients. Some perfume components are known to cause or
enhance corrosion reactions, especially the citrus types, such as bergamots
and citronellal bases. Test packing is essential. Formulations that contain
water are especially critical.
HOUSEHOLD PRODUCTS
General Comments
The "household products" segment of the U.S. aerosol industry reached a
total of 1,424,100,000 units in 1988, accounting for 48.8% of the aerosol
industry total and making this the largest category. See Table 20 for
details. In Japan, the same segment amounted to 123,554,000 units in 1988,
amounting to only 25.5% of the industry total. In that country, the largest
market share of aerosols (44.3X) is held by personal care products.
In the U.S., the term "household products" includes all consumer aerosols
except for pesticides, personal care items, and foods and drugs. They are
administered by the Consumer Product Safety Commission (CPSC), which is a
federal agency created in 1972 to handle the Federal Hazardous Substances Act
of 1960, the Poison Prevention Packaging Act of 1970, and other laws. Among
other things, they recommend pre-market testing of aerosols for flamiability,
inhalation toxicology, skin and eye toxicology, ingestion toxicology, and
81
-------
TABLE 20, HOUSEHOLD AEROSOL PRODUCTS SOLD IN THE U.S. DURING 1988
Product Type Number of Units % of Total
Paints, primers, and varnishes
306,300,000
10.5
Paint strippers, "snow," decoratives
24,500,000
0.8
Room deodorants and disinfectants
181,200,000
6.2
Cleaners (glass, oven, rug, tile)
167,200,000
5.8
Laundry products (starch, pre-wash)
146,000,000
5.0
Waxes and polishes
129,100,000
4.4
Other (shoe polishes, anti-static
spray)
26,800,000
0.9
Refrigerant & air/conditioner
refills
90,700,000
3.1
Windshield & lock de-icers
5,700,000
0.2
Cleaners (automotive upholstery)
16,300,000
0.6
Engine degreasers
27,000,000
0.9
Lubricants and silicones®
92,900,000
3,2
Spray undercoatings
15,700,000
0.5
Tier inflator & sealants
34,400,000
1.2
Carburetor & choke cleaners
57,100,000
2.0
Brake cleaners
29,700,000
1.0
Engine starting fluid
30,900,000
1.1
Other automotives & industrials
42.600.000
1.5
1,424,100,000
48. 9b
aPenetrating oils, demoisturizers, rust-proofers, mold release agents, tablet
machine lubricants, etc.
aThe U.S. 1987 figures were 1,326,000,000 and 48.7%,
Note: During 1988, household aerosol products increased by 7.4% in unit
volume, compared with a 6.8% growth of the aerosol industry as a
who1e.
82
-------
(sometimes) dermal corrosivity. Additional clinical studies may be needed in
some cases. If the studies are not run, or if the overall results are not
placed on the label in a prescribed format, the agency will impose severe
sanctions on marketers whose products are found to be injurious to consumers.
In addition, any torts (lawsuits) will be much more readily prosecuted by
plaintiffs against.marketers whose product labels are found to not meet
federal standards.
As with all U.S. aerosol products, the primary content declaration must
be in units of weight (Avoirdupois ounces and pounds), although a volume or
weight subsidiary declaration in the metric system is acceptable. The size
of various signal words, statements of hazard, precautions, directions, weight
declaration and other informational statements is controlled by CPSC regula-
tions .
Most household aerosol products consist of a dispersion of solids or
liquids in a continuous liquid phase. For paints, a group of finely divided
pigments is suspended in a resin/solvent/propellant solution. For starches
and fabric finishes, as well as cleaners, a colloidal suspension or emulsion
of various organic materials is prepared in an aqueous solution. These
products are dispensed in various ways, as shown in Table 21.
Water-out emulsions are used for most cleaners, but oil-out types are
used for air fresheners, the foam-type charcoal lighters with approximately 5%
water, and certain other products. The choice of propellants is very broad.
In addition to all the propellants described above, isopentane (boiling point
- 29.8°C) , helium, oxygen, and even 0.2(t. filtered compressed air have been
used for a few specialty items. In the U.S. , CFC propellants may be legally
used for the product types shown in Table 4. Sweden, Norway, and Austria, for
example, have much shorter lists of exempted or excluded products, while most
other countries currently have either a production/importation restriction, or
no limitations at all.
In contrast with personal care products, pesticides, and most others,
household products often have very low quantities of propellant in the
83
-------
TABLE 21, HOUSEHOLD AEROSOL PRODUCT DELIVERY MODES
Produce
Delivery Mode
Air Fresheners
Hard Surface Cleaners
Foam-Type Charcoal Lighters
Lubricants; Decorative Strings
Boat Horns; Electronic Cleaners
Silica-based Absorbent Powders
Caulking Compounds
Lithium Stearate Grease
Talc-based Lubricants; Wind Direction
Indicators for Golfers
Spray
Foaming Spray
Foam
Stream
Gas
Liquid/Solid Spray
Paste
Gel
Powder
84
-------
formulas. For example, window cleaners often have 3 to 41, starches may have
5 to 6%, certain heavy-duty cleaners may have 6 to 82, and rug or upholstery
shampoos usually carry 8 to 10 percent. The minimum amount is determined by
the following factors:
• Gassing machine accuracy;
• Propellant seepage out of the dispenser during its shelf life;
• Propellant separation from the product during use, going into the
expanding head space to try and maintain pressure;
• Propellant discharge during use, because of its slight solubility or
entrainment in the concentrate; and
• Consumer misuse, causing momentary release of propellant phase
through the valve,
Perhaps the lowest level of hydrocarbon propellant was 1.8% n,butane,
used for a low-foaming window cleaner. After several years, the pressure and
use level were increased. As a general rule, the amount of nitrogen or
compressed air that can be pressure-filled into an aerosol can is about 1 gram
per 100 mL of capacity. At levels much above this, the pressure becomes
excessive.
Household aerosol products have a greater history of consumer complaints
than do other aerosols. This is because they have longer shelf and service
lives, often contain more powerful solvents, are stored in a greater diversity
of places and conditions, and are sometimes deliberately misused. Examples of
misuse are painting graffiti and the deliberate concentration and inhalation
of paint vapors and other aerosols as well. In the U.S., the "Extremely
Flammable" label seems to be limited to household aerosols.
The conditions of use have a profound effect on the degree of'flammable
hazard to the consumer or his property. Paints should only be used where
85
-------
adequate ventilation is available. A concrete block moisture sealer was
banned by CPSC in 1974 because it was 1001 flammable in composition and two to
three large cans were used at a time for basement waterproofing purposes.
Several lives were lost, and over a dozen houses burned down.
A fabric protectant product, designed to spray a fluoroacrylic oil and
water resistant film onto entire upholstered sofas and chairs, could not have
been responsibly marketed in flammable form (using acetone or ethanol as the
solvent, for example). This product has the following formula:
UPHOLSTERED FURNITURE STAIN-GUARD SPRAY
3% Fluoroacrylic or other stain-repellant active ingredient
1% n.Butyl Acetate (Extender)
91% 1,1,1-Trichloroethane - Inhibited
5% Carbon Dioxide
Since 96% of this formula is nonflammable, it has enjoyed great success
in an important niche area; however, it has an Ozone Depletion Potential (ODP)
of about 0.15. (The ODP is a relative index of ozone destruction efficiency;
the value reflects the atmospheric lifetime and the chlorine content of the
molecule.)
Household products have pressures that vary from about 2 to 8 bar at
21.1°G, which is the equivalent of 6.7 to 12.7 bar at 54.4°C. Those formulas
that have the higher pressures often use nitrogen, nitrous oxide, or carbon
dioxide as the propellant and are designed for use at very low temperatures
(such as -=10"C) . Applications include windshield de-icing, engine starting,
and dispensing a non-slip surface on ice for cars stuck in snow or ice. These
gases will still retain about half their room-temperature pressure when the
dispenser is chilled to -10°C, whereas most of the other propellants will sink
down to such low pressures that the products become essentially unusable.
86
-------
Window Cleaners
The window cleaner, developed in 1954, was the first of a large array of
water-based cleaning sprays, such as hard surface cleaners, whitewall tire
cleaners, oven cleaners, bathroom (basin, tub, and tile) cleaners, and
laundry cleaners for spot application to difficult stains on textiles before
general cleaning in the washtub or washing machine,
Window cleaner products are water solutions with from 5 to 12% hydroxylic
solvents, to which a very small amount of detergent is added. Iso-propanol
(C3H7OH) is nearly always used because it is a good grease solvent and its
odor is associated with cleanliness. Additional odorants are optional. Some
marketers prefer to add ammonium hydroxide (NH40H) in concentrations of up to
0.3% of the commercial 29% solutions of ammonia (NH3) in water. The ammonia
actually does little cleaning, but consumers associate its odor with cleanli-
ness. Sometimes a minor amount of fragrance may be included. Oily materials
and excess amounts of detergent must be avoided, or a film may be left on the
glass surface, giving a halo effect in some situations. The percentage of
propellant in the formula is usually 3.2 to 5.0% isobutane.
The organic grease-cutting solvents may include butoxyethanol (C4Hg0-
CH20H), isopropanol (C3H70H), propylene glycol monomethyl ether [H0CH2-C(CH3)H-
OCH3) , and propylene glycol monobutyl ether [HOCH2-C(CH3)H-OC4H9] . The ratio
is about two parts of isopropanol (C3H7OH) to one part of one or two of the
solvents. The detergent selection is more critical to success.
Apart from the detergent benefit, a certain amount of foam structure is
needed to show where the product has been applied and also to prevent dripping
from vertical surfaces. If the foam is too voluminous or stable, the wiping
cloth will simply push it around, without removing it by absorption. Also,
too little detergent will reduce cleaning action, while too much will cause
streaking on the cleaned glass surface. Some typical window cleaner formula-
tions are shown in Table 22 and two specialized glass cleaner formulations are
shown in Table 23.
87
-------
TABLE 22. WINDOW CLEANER FORMULATIONS
Ingredients
Formula A
m
Formula B
(%)
Formula C
m
Isopropanol - 99%
4.0
5.0
4.0
Propylene Glycol Monoethyl Ether
3.0
2.5
Butoxyethanol
2.0
Sodium Lauryl Sulfate®
0.2
Lauryl Di-isopropanolamide
0.1
0,1
Ammonium Lauryl/Myristyl Alcohol
EO 3:1 Sulfate
0.2
0.1
Sodium Nitrite
0.1
0.2
0.1
Ammonia (29% NH3 in Water)
0.2
0,2
0.2
Deionized Water
89.0
88.5
90.0
Isobutane A-31
3.5
3.3
3.5
aSuch as Sipon WD, a product of the
American Alcolac
Corp.
88
-------
TABLE 23. ANTI-FOGGING OR ANTI-STATIC GLASS CLEANER FORMULATIONS
Ingredients
Formula A
Formula B
1%)
Dioctylester of Sodium Sulfosuccinic Acid3
Silicone Glycol Copolymer1*
Alkoxylated (8) n,nonylphenol6
Propylene Glycol Monoethyl Ether
Isopropanol - 99%
Morpholine
Deionized Water
Isobutane A-31
0.05
0.30
0.10
3.52
8.00
0.03
84.00
4.00
0.08
0.40
3.'49
10.00
0.03
82.00
4.00
aAs Aerosol OT-100, by the Chemical Product Division of the American Cyanamid
Company, or Monawet M0-70E by Mona Industries, Incorporated.
bAs Dow Corning 193 Surfactant, by the Dow-Corning Corporation. Water-
soluble, gives gloss, non-tackiness, anti-fog, surface tension depression,
and anti-static properties.
cAs Triton W-30 by the Rohm & Haas Company, gives added grease removal and
cleaning power.
¦6
89
-------
The products in Table 22 are used mainly for windows, but they can also
be employed to clean refrigerators, stove tops, kitchen counter tops and other
hard-enameled, painted, or chinaware surfaces. Because of their special
properties and somewhat higher cost, the aerosols in Table 23 are used more
for bathroom mirrors (to prevent steaming), where anti-static properties are
desired, and where a relatively glossy, polished appearance of the glass
surface is desired. One version of this type of product is eyeglass lens
cleaner, with dispensers in the 15-gram size that use metered spray valves
delivering approximately 50 microliters per actuation. These products give
about 300 actuations. Despite a general preference for the small sizes,
containers holding as much as 460 grams of "Lens Cleaner - Antifog" are on the
market.
Sorav Starch
The self-pressurized starch was developed around 1958 and used about 4%
of highly refined corn starch as the essentxal ingredxent. Some of these
starches can be dispersed into the aqueous phase at temperatures as low as 30
to 35°C, but others may require pre-cooking a 20% starch/borax (Sodium
Tetraborate 10-Hydrate; Na2B407*10H20) with live steam at 4 bars and 150°C.
The resulting thin paste, now concentrated to 18% solids as the result of some
condensation of the steam, drops into the batch-making tank containing
agitated water and is quickly dispersed. The other ingredients are then
added, after which the pH is adjusted to about 8.2 at 25 ° C.
Starch dispersions have been corrosive to cans, but if ingredients with a
low chloride content are selected, and sometimes if a modest amount of
corrosion inhibitor is added, a single-lined can is sufficient for a two- or
three-year shelf life. One starch formula that uses 0.04% sodium benzoate
inhibitor has been successfully marketed in a plain 4.48 g/m2 (0.20 lb/ft2)
container. If the starch contains a significant amount of chloride ion
corrosion promoter left over from sodium hypochlorite (NaCIO) bleaching
operations, corrosion can become a significant problem and a double-lined can
must be used, along with 0.20% sodium nitrite or similar inhibitors. Three
typical starch formulations are shown in Table 24.
90
-------
TABLE 24. SPRAY STARCH FORMULATIONS
Ingredients
Amizo No. 513 Pearl Starch
Penford Gum 290 or Equivalent
EO-Size 5795 Starch or Equivalent
Sodium Tetraborate 10-Hydrate
Silicone emulsion LE-463, 346 or
equal. (60% Active Ingredient)
Silicone antifoam emulsion, as
SAG-470 by Union Carbide
Sodium Nitrite or Sodium Benzoate
Fragrance
Glutaraldehyde (50%) or
Formaldehyde (37% in Water)
' Optical Brightener; as Tinopal 4BM
Deionized Water
Isobutane A-31
Formula A Formula B Formula C
m ai m
2,30 — —
_ 2.75
3,00
0.30 0.40 0.45
0.40 0.50 0.45
0.15 0.10 0.10
0.15 0.10
0.02 0.03 0.03
0.04 0.05 0.03
0.02 ----
91.20 91.70 90.00
5.50 6.00 5.84
Note: Adjust pH to 8.4 + 0.2 at 25*0. using triethanolamine (99%) or a 10%
solution of sodium hydroxide.
The optical brightener ingredient is now rarely seen. It adds cost
and has only slight marketing appeal.
If available, glutaraldehyde is preferred over formaldehyde, since
the latter is less effective as a microbicide and may be a low-order
carcinogen. Glutaraldehyde is marketed by Union Carbide
Corporation.
91
-------
The sodium tetraborate, sdd@d as the 5- or 10-hydrate , combinss chetni -
cally with the starch to give it better properties, such as less buildup on
the sole plate of the iron, and also functions as a corrosion inhibitor. The
silicone emulsions increase the easy slip of the iron over the cloth, so that
the user has less fatigue and almost no wrinkling or bunch-up problems. The
starch foam should quickly absorb into the textile, and should not be pushed
around by the iron. If this is not the case, either a 10% or 100% silicone
anti-foamant is added. This ingredient consists of a silicone oil that
contains billions of tiny sharp splinters of silica (Si02). The silica acts
to puncture the foam bubbles so that they quickly collapse. Antifoams are
used in about half of all starch products.
Since starch solutions are nutrients for bacteria, yeasts, molds, fungi,
and rickettsia, it is necessary to perform the following steps during produc-
Pasteurize the deionized water, or filter it at 0.2 p. to remove
microorganisms. (Resistant strains of pseudomonads are hard to kill
chemically, but they are eliminated by heating for one minute at
40°C or higher.)
Sanitize the batch-making tank, the concentrate filler, and all the
pumps, filters, piping, and other equipment.
Do not hold the starch concentrate for more than 72 hours, and then
only in covered tanks.
Flush the deionizer beds periodically with a strong formaldehyde
solution, to prevent the proliferation of microorganisms on the
re sins.
Some fillers also run a Total Plate Count (IPC) study on starch batches
and finished aerosols. Since these tests require 48 hours for a reliable
result, the batch will normally be packed into cans and corrective action will
be severely limited. The best result will indicate that there are "fewer than
tion;
92
-------
10 microorganisms per cubic centimeter of product," Therefore, the pos-
sibility of proliferation still exists. Experience with starches, fabric
finishes, mousse products, and others that can support microbial growth
suggests that the possibility of growth is low once the aerosol can has been
packed. For example, non-facultative aerobic bacteria generally die from lack
of oxygen. In the rare instances of starch contamination, bacteria have
caused "ropiness," or little tendrils of retrograded material in the product,
leading to valve problems and odors from triethylaxnine and other substances.
Most starch formulas use 0.03 to 0.035% Formalin (37% formaldehyde, HCHO,
in water). Sodium o.phenylphenate is still occasionally used. However, a
preferred material is glutaraldehyde [CH2(CH2*CHO)2] . This material has very
broad spectrum activity, is low in cost, effective at concentrations even
lower than formaldehyde, and does not sometimes sting the nose of the user
during the ironing process.
A significant amount of work has, gone into refining the designs of valves
that will be best for starches. The best spray pattern, for instance, is a
"doughnut" or torus shape, without "hot spots" or areas of extra-heavy product
concentration. This pattern gives the most uniform spray density as the spray
is sprayed across the fabric.
Most starches in the U.S. now use either vertical-acting or toggle-type
valves whose button and stem are separate components. In general, the buttons
are of the two-piece type, with a plastic insert of 0.46 to 0.50 mm orifice
design. However, a new "pseudo-mechanical breakup" one-piece button by the
Precision "Valve Corporation is now being used commercially.
During product development, valve candidates are tested against produc-
tion or commercial control units for the incidence of valve problems. The
test often involves 72 dispensers and lasts two weeks. The caps are left off
to enhance product evaporation at the valve.
Protocols differ, but one starts on a Monday, with 48 cans being sprayed
for 5 to 10 seconds on the following schedule: 2, 2, 3, 2, 2, and 3 days, and
93
-------
24 cans being sprayed every seven days. The results are recorded in the
following ways:
* Clear (Normal);
• Streams--three seconds or less--then clears;
• Streams --sustained streamer--over three seconds; and
* Flugger,
If more than two sustained streamers or one plugger are encountered, the
valve or formula should be adjusted to be more reliable. If the control,
using a different valve, gave acceptable results, this suggests that the
experimental valve needs improvement, not the formula.
Starch products work better on cottons and on 50% cotton and 50% poly-
ester fabrics than on textiles of higher polyester content, i.e., the so-
called "synthetics." Some marketers have developed Fabric Sizing or Fabric
Finish aerosols especially for these synthetics. As the market for synthetics
diminished during the last 10 years or so, consumers began to discover that
they liked the performance of these fabric finishes on straight cottons and
high-cotton blends. They did not have the relative stiffness of the starches,
but gave the fabrics lubricity, a better feel or handle, and an impression of
heaviness and brighter colors, making them seem more like new garments. since
the product was based on sodium methylcellulose gums, the Fabric Finish
produced a somewhat higher-quality spray and had a higher-quality image than
the starch. It is a useful supplementary product, and sales were estimated to
be about 12 to 14% of the starch market in the U.S. in 1988. Table 25
presents a formulation for aerosol fabric finish.
Heavy-Duty Hard-Surface Cleaners
This product was an outgrowth of the window cleaners. It is sold in two
versions: one with a microbicide, and the other without such an ingredient.
If the cleaner has a microbicide and is labeled accordingly, in the U.S. it
falls under the jurisdiction of the Environmental Protection Agency (EPA)
94
-------
TABLE 25. FABRIC FINISH FORMULATIONS
INGREDIENTS FORMULA
(%)
Sodium Methyl Cellulose (Combination of low and 0.9
medium-low viscosity products).
Technical Grade preferred.
Polyethylene Glycol (Mol.Wt. 400)
0
9
Cocoamino-propionic Acid (60% in water)3
0
02
Dimethylsilicone Emulsion (60% in water)
0
3
Silicone Anti-foam (100%)
0
03
Ammonium Hydroxide (29% NH3 in water)b
0
02
Glutaraldehyde (50% in water)
0
03
Sodium Nitrite
0
05
Fragrance
0
05
Deionized Water
92
70
Isobutane (A-31)
5
00
®Deriphat 151, by Henkel Corporation.
''Used to neutralize the Deriphat 151 (Acid) and adjust the pH value to
8.6 + 0.2 at 25°C,
95
-------
FIFRA and is subject to a heavy burden of microbiological testing, label
review, and confidential formula disclosure before marketing. The delay-
period is currently one to two years, and an annual registration fee must also
be paid to EPA and to state agencies. Some marketers elect to include
microbicides in their products and sell them without making any claims, since
the cost differential is extremely small.
The first hard-surface cleaner was introduced around 1961. The products
are characterized by a combination of non-ionic and tetrasodium ethylene-
diamine tetraacetate (Na4EDTA) detergents, plus various alcohol- or glycol-
based solvents in a water base. Two typical hard-surface cleaners are shown
in Table 26.
The tetrasodium EDTA, present at 1.90% (Formula A) and 1.52% (Formula B)
is effective at removing calcium carbonate, which it does by a sequestering
action, producing soluble calcium ethylenediaminetetraacetate [Ca2(EDTA)].
The dissolution process is a,slow one if the lime has any significant thick-
ness; therefore, the main thrust is one of preventive maintenance. Rust
deposits are similarly dissolved. These uses suggest various bathroom
applications.
Higher pH versions, sometimes with 25% deodorized kerosenes added, have
been used as whitewall tire cleaners. Anhydrous versions, generally contain-
ing about 5% non-ionic surfactant, 20% xylenes, 72% deodorized kerosene, and
3% carbon dioxide are used for cleaning the exterior of car engines. After
use, the cleaner can be flushed away with tap water. It is generally ad-
visable to perform the cleaning operation outside on a cool engine that is not
running. Hydrocarbon propellants, such as propane (A-108), have been used for
these products, but they are not recommended because of their flammability.
A second anhydrous version, in this case not containing any surfactant
materials, is carburetor and choke cleaner. It typically contains 60% toluene
or (better) xylenes, 30% diacetone alcohol or acetone, and 10% propane. It is
obviously extremely flammable, and should be used in small amounts and with
care in an open and well-ventilated area. The engine should be cool and
96
-------
TABLE 26, HARD SURFACE CLEANER FORMULATIONS
INGREDIENTS FORMULA A FORMULA B
m m
Atlas G-3821 Detergent - 0,50
Tergitol 15-S-9 (Non-ionic surfactant) 0.50
Tetrasodium EDTA (38% in water)3 5.00 4,00
Triethanolamine - 85% - 1,00
Propylene Glycol Monobutyl Ether 5.00 6,00
Sodium Meta-Silicate 5-Hydrate 0.10
Sodium Sesqui-Carbonate - 0.10
Morpholine 0.20 0.15
Ammonium Hydroxide (29% NH3 in Water) - 1.00
Sodium Hydroxide (50%) or Citric Acid (50%)b q.s.° q.s.c
Fragrance 0.10 0.15
Deionized Water 82.10 79.90
Isobutane (A-31) 7.00 7.20
aAlthough a specific surfactant was mentioned, any one or more of the
following may be used:
* Linear primary alcohol polyglycol ether (9 to 12 mol ethylene glycol (ET0);
average);
* Linear secondary alcohol polyglycol ether (9 to 12 mol ETO; average); or
° Nonylphenol polyoxyethylene (9 to 13 mol ETO; average).
b These reagents are used to adjust pH value to 10.5 + 0.2 at 25"C.
c Quantum sufficit (a sufficient quantity).
97
-------
turned off. Any excess should be removed before the car is restarted. The
use of a nonflammable propellant, such as HCFC-22 or carbon dioxide, would act
to make the overall product only slightly less flammable.
The final version of a hard-surface cleaner is oven cleaner. There are
both caustic'formulas and "pre-caustic" formulas. The caustic ones use from 4
to 8% sodium hydroxide activated by triethanolamine to cut through the
varnish-like deposits of grease and food spatters on oven surfaces. The other
form contains alkali metal acetates and sometimes other organic salts in a
water and surfactant slurry. The product is sprayed on the oven surfaces,
after which the oven is closed and heated. This causes the organic salts to
pyrolyse via a distinctly two-stage process, producing the oxide, carbon
dioxide, and water. The oxide then hydrates to the hydroxide form, which
begins dissolving the baked-on greases and other residues. Table 27 presents
the formulations of oven cleaners.
The caustic nature of Formula A in Table 27 allows it to rapidly corrode
aluminum surfaces, and this is often mentioned on labels. Under U.S. regula-
tions, if an oven cleaner contains more than 2% of a caustic such as sodium
hydroxide, the dispenser must be fitted with a child-resistant closure. The
same regulations permit one exempt package size designed for homes without
children and for adults with physical problems like arthritis who would
otherwise have great difficulty using the product. In practice, the market-
place has shown a strong preference for the products without the specxal
closures, so that dispensers that have this feature are now only a token part
of the overall sales picture. Self-cleaning ovens in the U.S., Europe, and
other areas will reduce sales of aerosol oven cleaners.
The other type of heavy-duty cleaner is designed for the specialty
cleaning of textiles. The best known is the pre-laundry cleaner stain
remover, which is sprayed directly onto a stain and onto the inner neck band
of shirts, shirt cuffs, and other areas where dirt and grime seem to concen-
trate. After spraying, the garment may then be laundered. Some formulations
contain enzymes for the more effective removal of proteinaceous stains; e.g.,
grass stains or bloodstains. Others use a mild detergent system and claim
98
-------
TABLE 27. OVEN CLEANER FORMULATIONS
INGREDIENTS' FORMULA A FORMULA B
m m
Potassium Formate - 6.0
Potassium Acetate - 6.0
Sodium Hydroxide 5.0
Calcium Dodecyibenzene Sulfonate - 3.0
Compatible Thickener - 0,5
Sodium Nitrite 0.2 0,2
Triethanolamine - 99% 1.0
Tetrasodium EDTA - 382 1.0
Deionized Water 87.8 78.3
Isobutane (A-31) 5.0 6.0
99
-------
that the treated garments may be stored for several days before washing, if so
desired.
The two major formula types are anhydrous and water-based. The latter
generally contains 25 to 40% water. Originally, soil removal was accomplished
by using 20 to 25% perchloroethylene, in addition to the usual anionic/non-
ionic detergent system and hydroxylic solvents. The perchloroethylene
(C12C=CC12) was a major benefit to the cleaning activity, doing such a good
j ob, xn fact, that many users complained that their clothes were cleaner and
whiter where the product was applied than in the other areas. Some wondered
if the product contained a bleaching agent. The marketers maintained a
service for taking care of shirts and other garments submitted to them by
consumers for correction or replacement, and what they normally did was to
immerse the entire item in the concentrate for a few minutes, rinse it off,
dry the garment and return it. The super-cleaning ability of the aerosol
product had removed soils that resisted ordinary cleaning methods and that had
built up on the garment over months of use, turning the cloth slightly grey or
slightly tan. Eventually, the perchloroethylene was deleted, after the Bruce
Ames "mutated Salmonella" test suggested that it might be a carcinogen and
after a number of more odor-conscious consumers complained that traces of the
chlorocarbon odor could be detected in clothes even after they were automati-
cally washed, dried, and ironed. The two main formula types of textile
cleaners are illustrated in Table 28.
The isopropanol functions as a mild cleaner, but (just as importantly) as
a foam destabilizer and suppressant. Ethanol may also be used for this
purpose. In either case, percentages may vary according to the foaming
tendencies of the overall formula.
Carpet and Rug Cleaner
This unique product was introduced around 1964 by S. C. Johnson & Son,
Inc. It is presented in a very large can, such as the 75x192 mm (USA:
300x709) or the new, necked-in 72x261 mm (USA: 211-213/214x1005), which have
100
-------
TABLE 28. PEE-LAUNDRY CLEANER FORMULATIONS
INGREDIENTS
FORMULA A
FORMULA B
Linear primary or secondary alcohol
polyglycol ether [2 to 4 mol
ethylene glycol (ETO)]
12.0
-
Linear primary or secondary alcohol
polyglycol ether (7 to 10 mol ET0)a
12.0
10.0
Diethylene Glycol Monomethyl Ether
12.0
• 5.0
Sodium Laurate/Myristate
0.4
-
Isopropanol - 99%
4.0
5.0
Low-odor n.Paraffinic or iso.Paraffinic
Solvent (C10 - Cu Hydrocarbons)
20.0
786 , 7
Ammonium Hydroxide (28% NH3 in Water)
0.5
-
Fragrance (Typically lemon/lime)
0,5
0.5
Enzyme Concentrate (Optional)
1.0
-
Deionized Water
30.1
-
Propane A-108 or Propellants A-85
7.5
-
Carbon Dioxide
-
2.8
aMay be replaced with octyl or nonyl phenol polyoxyethylene (9 to 13 mol ETO)
or other non-ionics of similar HLB value.
101
-------
capacities of about 820 and 980 mL, respectively. This allows one can to
clean a carpet of maximum area.
The products use sodLvm laury 1 sulfate , whi.ch acts to pull the dirt and
grime out of the carpet fi.bers and then dri.es so that vac uum- c 1 eanin^ can
effectively remove it. An emulsified polymer is included to prevent rapid re-
soiling of the absorbent fibers. Table 29 gives a typical carpet cleaning
formula.
Intensive wetting of the warp and woof of the carpet is not desired, as
would occur if sodium stearate/palmitate soaps were to be used. Excessive
wetting lengthens drying time, and might also cause mold formations at the
base of the carpet or rug. The sodium/magnesium lauryl sulfate combination
wets only the surface of the fibers, where most of the dirt is collected. In
particular, the magnesium lauryl sulfate helps surround the dislodged dirt
into a more friable, dried mass on the surface of the fibers, for easy removal
with a vacuum cleaner.
The sodium lauryl sarcosinate functions as a corrosion inhibitor, more
or less specific to lauryl sulfate ion and ethoxyla'ted or propoxylated lauryl
sulfate moieties. However, for it to function well, there must be a virtual
absence of chloride ion, bromide ion, and copper ion. The highly purified
"toothpaste" grade of sodium lauryl sulfate (SLS) is acetone extracted or
otherwise treated to remove any chloride ion that may be present, depending on
the method of synthesis used. Sodium nitrite has often been added to these
formulas as an additional corrosion inhibitor.
The upholstery shampoo is a related aerosol product that uses such
detergents as sodium lauryl sulfate or morpholinium stearate, plus ingredients
such as lauryl-monoethanolamide as a corrosion inhibitor and foam stabilizer.
The foam is worked into the upholstery covering with a rough cloth or soft-
bristle brush, then allowed to dry before removal. A water-wipe is often used
to remove the last bits of product, so that a slightly soapy feeling will not
be noticed.
102
-------
TABLE 29. RUG AND CARPET CLEANER PRODUCT FORMULATION
INGREDIENTS
FORMULA
(%)
Sodium Lauryl Sulfate (very low in Chloride Ion}3
1.60
Magnesium Lauryl Sulfate (very low in Chloride Ion)b
• 1.20
Sodium Lauryl Sarkosinate - (30% in Water)c
3.00
Styrene Maleic Anhydride Copolymer - (15% in Water)
20.00
Optical Brightener; as Calcofluor SD (Optional)
0.02
Ammonium Hydroxide (28% NH3 in Water)d
0.16
Fragrance
0.08
Deionized Water
66.44
Isobutane A-31
7.50
aAs Haprofix 563, by the Onyx Division of Witco Chemical Co.
bAs Maproflx Mg, ^
cAs Maprosil 30.
dUsed to adjust the pH value to 9.8 ± 0.2 at 25°C, although up to about 1,5%
may be used if the clean odor of ammonia (NH3) is desired.
103
-------
Silica-Based Absorbent Fabric Cleaners
/
A relatively unique aerosol product uses the extreme absorbency of very
finely divided silica powder to literally soak up stains by capillary action.
Silica, which has been made by the pyrolysis of silicon tetrachloride, is able
to absorb hundreds of times its own weight of various liquids, even greases
and gels, and this principle is used here. The silica, in the form of an
essentially nonflammable slurry in 1,1,1-trichloroethane, is sprayed onto the
fabric to he treated. The solvent quickly evaporates, causing the silica
powder to absorb any available liquid materials. After complete drying, the
loaded silica is brushed off the cleaned fabric, using light strokes, so as
not to embed it in the fiber matrix. The aerosol dispenser often comes with a-
special plastic cap whose top is molded to have 100 to 200 thin, comb-like
tines or bristles. 'The cap is used to brush off the silica.
A typical formulation follows:
fiRQADRCWT QTT TTA n 17 AMI? 13 FADMTTT ATTAXTO
rvDOvlvDEjLH 1 D1 Li^n, rUCvTlULAi lUIiD
Ingredients Formula ('%>
Fumed Silica Powder 6.00
1,1,1-Trich1oroethane 68.00
Isopropanol - 99% 10.00
Fragrance, 0.05
Propane A-108 15.95
The selection of silica powder and a valve with optimum design features
are keys to success, since with an incorrect combination, valve plugging may
occur. The user can correct this problem only 40 to 60% of the time. There
are also considerable problems with evaporation, concentrate losses, toxicolo-
gical response to 1,1,1-trichloroethane vapors (unless used in a well-
ventilated room) and weight control in the manufacture of these products, so
that one should not undertake their manufacture lightly.
104
-------
These cans, when actuated under totally non-conductive conditions, will
build up a static charge in the 67,000 to 285,000 V range, based on the
results of one fairly large study. This does not adversely affect the
consumer in any way, but if a filled can is jammed, defective, or otherwise
quickly discharges the contents in a gas house while momentarily not grounded,
the spark to a nearby grounded surface may cause ignition of the discharge
plume, perhaps with serious consequences. No viable corrective methods for
this phenomenon have yet been devised.
Air Fresheners
The air freshener was the second aerosol product to be developed commer-
cially, after insecticides. It was marketed in the U.S. as early as 1948,
mainly by oil companies, and then by chemical specialties marketers such as
the Colgate-Palmolive Company. The formulas were initially combinations of 1%
fragrance, 15% low-odor petroleum distillate, and 84% CFC-12/11 (55:45), until
about 1961, when the S. C. Johnson & Son, Inc. firm began to market their line
of "Glade" Air Fresheners in a water-based form. These formulations now make
up the largest segment of this category. The remaining segments are the
"super-dry" sprays, typically containing 99% propellants, and the alcoholic
types that average about 50% ethanol-. Typical examples of the three versions
are presented in Table 30. The use of dimethyl ether propellant in Formula B
is justified by the increased solvency of perfume resins that might otherwise
precipitate.
As mentioned earlier, Formulas B and' C have a Volatile Organic Compound
(VOC) level of essentially 100 percent. After February 28, 1990, the State of
New Jersey (U.S.) has forbidden the marketing of these formulas unless the VOC
content is somehow reduced to 50% or less. The use of 1,1,1-trichloroethane
(not a VOC, though it has a potential for stratospheric ozone depletion) is
not permitted. Ultimately, it may be necessary to use a combination of
something like 6 parts water and 44 parts HFC-152a (replacing 50 parts of
Propellant Blend A-60) to be in compliance with the regulations. This change
will have a major effect on the retail cost of these products.
105
-------
TABLE 30. AIR FRESHENER FORMULATIONS
INGREDIENTS
Fragrance
Odorless Petroleum Distillates
Lanpolamide 5 Liquid (Croda, Inc.)
PEG Lanolinamide and PEG
Lanolate ester - 50% in
Deodorized Kerosene (HLB - 3.65)
S.D. Alcohol 40-2 (Anhydrous)a
Sodium Benzoate
Deionized Water
Propellant Blend A-60b
Dimethyl Ether
FORMULA A FORMULA B FORMULA C
m [%j m
1.00 1.50 2.00
6.28 - 6.00
0.72
38.00
0.15
59.85 - 4.00
32.00 90.00 50.00
8.50
aSpeeially Denatured ethanol, where 400 g of tertiary butanol [
-------
Disinfectant/Deodorant Sprays
This category has often been compared with air fresheners, but there are
more differences than similarities. First, the "D/D" products are regulated
by the U.S. EPA, so that planning and formula development should be carried
out at least three years before the marketing phase begins. Secondly, most of
the label is given to a description of the formula, disinfectant claims, and
directions for disinfecting hard surfaces. The ability of the product to
function as a space spray is limited by the low levels of propellant used,
since the main use is as a surface spray, and labeled uses limit space
spraying to storage rooms, closets, and other enclosed spaces 'for deodorizing
purposes only. (Fragrance benefits are not mentioned on the label, although a
pleasant fragrance is always included, even in "Hospital Strength" D/D
products.)
Two formulation types and two propellant types are currently in use. The
base product contains either an o.phenyl-phenol system or a quaternary
ammonium disinfectant system in a hydro-alcoholic solution. Either 5% carbon
dioxide or about 20% hydrocarbon propellant blend is used as the pressurizing
medium. In terms of units sold, the o.phenyl-phenol and carbon dioxide system
is probably the most popular.
The EPA requires that the labels of these products list the active
ingredients, plus certain other data. An example from the label of one such
product is shown below:
Active Ingredients:
n-Alkyl (60% C14, 30% C16, 5% C12, 5% C18) dimethyl
benzyl ammonium chlorides
n-Alley 1 (68i C12» 32% 0^) dimethyl ethylbenzyl
ammonium chlorides
Ethanol
n-Alkyl (92% C18, 8% C:6) n-ethyl morpholinium ethyl
sulfate
. . . . .0.072%
. . . .53.088%
0.072%
.0.040%
Inert Ingredients:
46.728%
Contains sodium nitrite
107
-------
The first two ingredients are available as BTC 2125M, which is sold as a 50%
active ingredients solution (and in other strengths) by the Onyx Division of
the Witco Chemical Company. Similarly, the last n-Alkyl compound is sold as
Atlas G-271, generally as a 35% active ingredient solution, by ICI America,
Inc. Two examples of these formulas are provided in Table 31.
The quaternary ammonium chloride products came along well after the
market for D/D aerosols was well established and approaching 100,000,000 units
sold a year in the U.S. The strengths and weaknesses of their antimicrobial
spectrum of efficacy is different from that of o.phenyl-phenol and its close
derivatives, as would be expected. Also, since the quaternaries are much less
volatile than the substituted phenols, the protective effects may last longer.
This may be important when considering regrowth potential for molds in
leather, wood, books, and other relatively porous substrates. No one has
attempted to market a product containing both microbial types, perhaps because
of the degree of toxicological and microbiological testing that would be
required.
Since they have chloride ion (a strong corrosion promoter) double-lined
cans and heavy amounts of strong corrosion inhibitors have been required to
achieve an adequate shelf life for the quaternary ammonium formulations. For
some time, combinations of sodium nitrite and morpholine were preferred for
the inhibitor system, but after it was found that up to about 10 parts per
million of morpholinium-N-nitrosaraine (a carcinogen) could be formed in situ
over one year of room-temperature storage, marketers acted to change the
sodium nitrite to sodium benzoate and eliminate the reaction.
Disinfectant Cleaners
This type of product was partially covered under "Hard Surface Cleaners"
(see Table 26), but the disinfectant version adds a new dimension of cleaning
that is generally appreciated by the consumer. Most of the larger marketers
of heavy-duty cleaners are able to cope with EPA's requirements for pre-
marketing registration, plus federal and state fees, and have preferred this
type of presentation. The disinfectant cleaner is really nothing more than
108
-------
TABLE 31. DISINFECTANT/DEODORANT FORMULATIONS
INGREDIENTS
FORMULA A
FORMULA B
m
m
o.Phenyl-phenol (98% purity)
0.110
BTC-2125M (50% in water)8
, -
0.288
Atlas G-271 (35% in water)3
-
0.114
S.D. Alcohol 40-2 (Anhydrous)13
73.380
52.068
Fragrance
0.110
0.110
Sodium Benzoate
0.200
0.220
Morpholine
"0.200
0.200
Deionized Water
21.000
25.000
Propeliant Blend A-40c
-
22.000
Carbon Dioxide
5.000
-
aFor chemical compositions, see preceding page.
bFor chemical composition, see note 'a' of Table 30.
c10 wt X propane and 90 wt % isobutane.
109
-------
the standard type, except for the inclusion of 0.20% or so of biocidal
material in the formula. When a quaternary microbieide is used, the formula
has to be adjusted to eliminate incompatible anionic surfactants that might
precipitate the active cationic moiety. Some remain acceptable, as will be
seen in the formulation presented in Table 32.
Normally, two types of valves are used for both these and the regular
hard surface (basin, bath, and tile) cleaners. The can may be used in
different positions, including some where the dip tube may protrude into the
gas space. The simplest and least costly approach is to use a valve with a
very large diameter, a "jumbo" dip tube, with an inside diameter of about 6.4
mm. For the relatively long cans in general use, such tubes will contain 7 to
8 grams of product. If the container is turned upside down--for instance, to
more comfortably spray the base of a toilet bowl--the special dip tube will
hold sufficient product for about 6 seconds of spray time. After this, gas
will be emitted, signalling the consumer to reverse the can for a second or
two. In the second approach one might use the Sequist Valve Company Model NS-
36 (Ball-check) valve. A 4~mm diameter stainless steel ball travels in a
short plastic slot, just below the valve. With the can upright, an orifice at
the bottom of the slot is closed off, forcing the product to travel up the dip
tube and through the valve. With the can inverted, the ball closes off an
orifice at the opposite end of the slot. This acts to plug the opening from
dip tube to valve and at the same time opens a "vapor-tap" type orifice
directly into the valve chamber. The valve has only two minor deficiencies:
it always leaks slightly between the plastic and the ball, to give a vapor-tap
effect, and secondly, it works poorly when the can is in an essentially flat
position. The price is significantly higher than that of the standard valve
or jumbo dip tube valve.
A good delivery rate for the hard-surface cleaners is about 1.23 g/sec at
21°C, at the*460-mm vacuum crimp pressure of about 2.54 bar at that tempera-
ture. A valve with a 0.46-mm stem and 0.41-mm MB-ST button will provide the
desired rate.
110
-------
TABLE 32, DISINFECTANT CLEANER FORMULATIONS
INGREDIENTS FORMULA
CD
Sodium Meta-Silicate 5-Hydrate 0.10
Tetrasodium EDTA (38% A.I, in Water)3 4.12
BTC 2125M (50% A.I. in Water)b 0.40
Sodium Benzoate 0.10
Sodium Tetraborate 10-Hydrate 0.10
Morpholine 0.20
Ammonium Hydroxide (As 29% NH3 in Mater) 1.10
Atlas G-3821 Non-ionic Surfactant0 0.50
Butyl Cellosolve (or similar)d 6.00
Potassium Hydroxide (45% A.I. in Water) 0.05
Fragrance 0.15
Deionized Water 80.18
Isobutane A-31 7.00
*Tetrasodium Ethylenediamine-tetraacetate, such as Cheelox BF-13, or
Versene 30 (Dow).
bSee previous pages for complex formula of ingredients.
cBy ICI America, Inc.
dBy Union Carbide Corporation. Propylene Glycol Monomethyl Ether may also
be used.
Ill
-------
Paint Produces
In 1988, the U.S. paints and coatings industry marketed approximately
325,000,000 units, ranging from very small touch-up paints to large-size units
for domestic or industrial furniture finishing. A substantial number of
filling plants specialize in self-fill or contract filling operations. It is
a complex area, with five main categories; enamels, lacquers, varnishes,
stains, and primers, with subgroups of each. Large numbers of colors have
also to be considered. The largest sales are for the alkyd- and acrylic-base
paints: Both are available in anhydrous and water-based formulations,
although the water-based techniques are better developed in some countries
than others, as is the use of dimethyl ether as a paint propellant. The
formulas to follow illustrate a bronze metallic specialty lacquer (anhydrous),
two alkyd types and an acrylic type. The last three are based on some
excellent work by DuPont that has been widely distributed. The term lacouer
refers to a coating that dries by the simple evaporation of the solvent
system. Originally, it related to the cellulosic varieties, but these have
been almost completely displaced by the thermoplastic acrylics. The acrylics
have better resistance to mild chemicals, weather, and sunshine. They are a
preferred base for various metallic finishes (aluminum, bronze, and gold
powder finishes) because of their low acid number and water-white color. Four
different paint formulations are illustrated in Table 33.
A prototype valve that might be evaluated is the Newman-Green Model R-10-
123 (0.33-mm vapor-tap), but with a butyl rubber seal gasket. The actuator is
a No. 120-20-18. This valve delivers the four products shown in Table 33 at
about 0.95 g/sec at 21.1°C.
During the development of various paint aerosols, alterations in the
formula or valve may be required if the applied product exhibits low gloss,
blushing, sagging, bubbling, peeling, deleafing of metallics, valve plugging,
poor adhesion, low durability, or other problems. For example, adding more
xylenes to Formula A would slow down the final drying of the film, resulting
in better smoothness and higher durability. The disadvantage must be weighed
against the two advantages, keeping in mind that the consumer will note the
-------
TABLE 33. VARIOUS AEROSOL PAINT FORMULATIONS
INGREDIENTS
ACRYLIC METALLIC
FORMULA A
(X)
ACRYLIC
FORMULA B
m
ALKYD
FORMULA C
OQ
ALKYD
FORMULA D
m
Acryloid B72 (50% A.I.)
Acryloid AlOl (40% A.I.)
Carboset 5I4H (40% A.I.)
Gold Powder #6238
Tint Ayd (Black WD-2350)
Beckosol 13-400 (75% A.I.)
Ammonium Hydroxide (29% NH^)
Titanium Dioxide Powder, R-940
Propylene Glycol Monomethyl Ether
Isopropanol
Nonylphenoxy Polyethoxy Ethanol
Fluoroacrylic FC-430 Surfactant
Hi-Sil T-600 (Silica)
Magnesium Aluminum Silicate
Drier: Cobalt Hydro Cure II
Drier: Zirconium Hydro Cem
Toluene
Xylenes
Acetone
Deionized Water
Hydrocarbon Propellant Blend A-85
Dimethyl Ether
Pressure (460-mm Vacuum Crimp bars at 21. 1°C.)
8.0
1.0
4.0
2.0
0.1
28.2
12.4
15.0
28.9
3.4
25.00
5.00
1.00
5.00
8.00
0.35
0.02
0.14
0.30
10.19
45.00
3.9
5.00
13.00
15
00
00
8.00
0.45
0.02
0.14
0.12
0.10
0.08
19.94
45.00
3.8
5.00
13.00
1.15
5.00
8.00
0.50
0.02
0.14
0.15
22.04
45.00
3.8
(Continued)
-------
Ingredient Sources:
Acryloids
Carboset
Gold Powder
Tint Ayd
Beckosol
Titanium Dioxide
Propylene Glycol MM Et
Nonylphenoxy Poly,
Fluoroacrylic
Hi-Sil
Magnesium A.S.
Driers
Dimethyl Ether
TABLE 33, (Continued)
Rohm & Haas Company
B. F. Goodrich Company
U.S. Bronze, et al,
Daniel Products Company
Reichhold Chemical Company
E. I. duPont de Nemours & Co., Inc.
UCAR PM - Union Carbide Corporation
Triton N-401 - Rohm & Haas Company
3M Company
PPG Industries, Inc.
Attagel 40 - Engelhard Corporation
Mooney Chemicals, Inc.
Dymel A - E. I. duPont de Nemours & Co., Inc.
-------
¦fe
disadvantage rather soon after the product is used, but may not detect the
other differences until later, if at all.
Paints and coatxngs are generally pa cited with a small glass marble that
helps agitate settled material back into a uniform dispersion. Also, to
prevent premature use by children or others, a tamper-resistant and tamper-
evident valve cover or protective cap is used. The outer cap is often colored
the same as the product within the can, or it may carry a self-adhesive top
label to help the customer make selections.
Furniture Polishes
The original aerosol furniture polishes were introduced around 1950.
They contained self-polishing floor waxes in a simple oil-in-water emulsion
form. In 1955, silicone emulsions were included, since they added lubricity
and made the rubbing out process much easier. They also improved the sheen
and conferred water resistance to the polish. At first, formulators added an
intermediate viscosity silicone, such as Dow-Corning DC-200 dimethylsilicone
fluid (1,000 cstks), at a low-volatiles level about the same as that of wax:
0.7 to 1.5% of the total. But as they found that silicones soaked into the
polishing cloth more readily than wax, they began to increase silicone levels.
In addition, it was found that combinations of lower- and higher-viscosity
silicones functioned better than the single intermediate viscosity type. The
higher-viscosity silicone added shine or brilliance, but too much caused the
polished surface to be subject to marking. Two illustrative examples are
shown in Table 34.
The preparation of furniture polish concentrates can present fire and
explosion hazards, especially if the more volatile aliphatic hydrocarbons are
used, such as Isopar C, which has a flashpoint of 5°G. Heating batches of
Isopar C to 80°C or so to facilitate the dissolution of waxes has caused four
major explosions and subsequent fires. This is because very heavy vapors of
the hydrocarbon seep over the tank rim, fall to the floor, and spread outward
until a spark or fire source is contacted. Less than 1 volume percent of
115
-------
TABLE 34. FURNITURE POLISH FORMULATIONS
INGREDIENTS
FORMULA Aa
m
FORMULA Bb
(%>
Wax S and Wax N (1:1 ratio) Hoechst
1.25
1.25
Silicone Emulsion LE-461 (50% A.I.) UCC
1.40
1.40.
Silicone Emulsion LE-462 (50% A.I.) UCC
0. 35
0.35
Arlacel C (Non-ionic surfactant) ICI Am.
0.15
1.25
Isopar C or E (C7 or C8 iso,paraffinics)
Exxon Oil Company
2.00
33.0QC
Lemon Oil, Technical Grade
0.75
0.60
Glutaraldehyde (50% A.I.) UCC
0.05
0.03
Sodium Nitrite
0.05
0.05
Deionized Water
86.00
44.67
Isobutane A-31
7.00
17.50
aOil-in-water version.
bWater-in-oil -version. (Better product; more costly.)
°Any n-paraffinic, iso.paraffinic, or multi-brancheate low-odor hydrocarbon
may be used, at 12 to 36%. About 20% is an average.
116
-------
flammable vapor in air is required for ignition. Air-tight compounding tanks
and good ventilation is required,
A related product is the wood paneling cleaner, conditioner, and polish.
Pre-finished plywood wall panels, natural wood kitchen cabinets, and similar
surfaces have relatively thin varnished or lacquered surfaces compared with
furniture, so that the use of water-based polishes like those just described
would result in some water penetration of the wood, and the finish would be
gradually lifted or peeled. As a result, these products are anhydrous and de-
eraphasize the use of wax-type ingredients. The formulation in Table 35
provides good gloss, sealing, and detergent resistance.
Car Windshield De-icers
The windshield de-icer spray is a product representative of dozens of
automotive aerosols. The most effective de-icer is methanol (CH3OH), and it
is used to some extent, despite its well-known toxicity and the corresponding
need for special labeling under various U.S. government regulations, such as
the CPSC regulations, Xsopropanol [ and n.propanol
are less hazardous but are less effective and more costly. Since a simple
alcohol or alcohol/water de-icer would allow refreezing of the liquid to occur
as soon as the alcohol was sufficiently diluted or evaporated, it is customary
to add a certain amount of glycol to formulas. Here again, ethylene glycol
(HG-CHz-CH2-0H) is the most effective, but it also is quite poisonous, so
propylene glycol [HO-C(CH3)H-CH2-OH] is used instead.
If very thin ice films are dissolved by an anhydrous alcohol/glycol
product, after which the alcohol largely evaporates, vision will be obscured
by the heavy glycol layer that remains, To resolve this final problem,
certain amounts of water are included in the formulas. The higher-quality
products will have about 20%, while the economy types may have as much as 50
percent. Table 36 presents a typical formulation.
117
-------
TABLE 35- WOOD PANEL POLISH FORMULATIONS
INGREDIENTS
FORMULA
(X)
D.C. 536 Fluid (An aminofunctional polydimethylsiloxane
copolymer - Dow Corning Corporation)
2.00
D.C. 200 Fluid (12,500 cstks) (Dimethylsiloxane polymer -
Dow Corning Corporation)
2.00
Witcaraide 511 - Witco Chemical Company
1.00
Isopar L and/or Isopar M - Exxon Company
26.50
Isopar K - Exxon Company
65.20
Fragrance
0.05
Isopropanol (anhydrous)
0.25
Carbon Dioxide
3.00
Pressure (460-mm Vacuum Crimp) bar at 21.1°C
7.40
118
-------
TABLE 36. WINDSHIELD DE-ICER FORMULATIONS
INGREDIENTS
FORMULA
m
Methanol - Technical Grade
54,00
Propylene Glycol - Technical Grade
18.00
Deionized Water
25,00
Morpholine
o
i—i
o
Span 80 or Igepal C0-410 Non-ionics
0,05
Sodium Benzoate
0.05
Carbon Dioxide
2.80
119
-------
The Igepal CO-410 (Rohm & Haas Co.) surface active agent is present in
the formula in Table 36 because it improves the wetting activity of the
formula, allowing it to penetrate more effectively into fissures and cracks in
the ice, and then between the ice and the glass, for faster removal.
PESTICIDE AEROSOL PRODUCTS
Pesticides consist of insecticides, insect repellents, disinfectants,
rodenticides, nematocides, herbicides, and a host of other products designed
to reduce or eliminate pests in size ranges extending from viruses to rats.
All these products fall under the purview of the EPA FIFRA if they are made or
marketed in the U.S. Other nations have similar regulations. When pesticide
products are designed for use on the skin in the form of "outdoor lotions"
that protect against solar radiation, poisonous plants, infections from
scratches, and also contain insect repellant, the EPA still has control but
may consult with other agencies, such as the FDA in this, case, before giving
pre-market clearance. Information has been presented earlier on the dis-
infectant cleaner and disinfectant/deodorant spray, which are regulated by the
EPA in the U.S.
Insecticides
The insecticide was the first commercial aerosol product, used as early
as 1944 for both military and domestic applications. These early sprays were
true "aerosols" (unlike any of. today's products, except one type) and used 85
to 90% of CFC-12 to disperse the pyrethrl n—contaxnmg concentrates . The f xrst
major segmentation of this product form came in 1953, with the introduction of
the bug killer: a coarse spray consisting of at least 75% kerosene-based
concentrate, used for surface wetting, instead of the usual space spray
format. By 1961, water-based space sprays came onto the market, and many
years later this technology was applied to the surface spray as well. Also in
the early 1960s, a "whole-house insecticide," or "total release indoor fogger"
spray was developed, typically using 85% CFC propellants. Other specialty
insect sprays were developed later in the 1960s. They included the wasp and
hornet spray, pressurized with nitrogen or carbon dioxide, and which could
120
-------
throw a stream or streaming spray up to 6 meters. A number of {jet-stock
sprays were also introduced. Later, hormonal flea-control sprays, biocidal
sprays, and other types were introduced.
The space sprays are now essentially all water-based, since the other
formulations were too costly and could not compete with the obvious economies
offered by combinations of approximately 65% water and 30% hydrocarbon
propellant. The only exceptions are the total release Indoor fogger (TEIF)
and toxicant/propellant (T/P) sprays.
The water-based space sprays can be closely compared with the air
freshener shown in Table 30, Formula A. By removing the perfume ingredient
and replacing It with a toxicant blend, the transition is complete. The
water-based space sprays include the flying insect spray, house and garden
spray, patio fogger, and a portion of the TRIP products. As a unit, they make
up approximately 55% of the insecticide aerosol volume.
The TRIF spray made a difficult transition during 1978, when CFC
propellants were banned in the U.S. Since it is designed to be latched open
and to discharge the entire contents of the can within two or three minutes,
there Is a greater inhalation and flammability hazard than is the case with
most aerosols, which release only a few grams at a time. The flammability
aspect related to two factors: the size of the container (and the number used
at one time), and the degree of product flammability, When problems have
occurred, they have been caused by gross consumer misuse; for example, when
two or more large cans have been set off in a relatively small area containing
an ignition source such as the pilot light of a stove (range and oven), gas-
fired refrigerator or gas-fired hot water heater. Table 37 presents three
forms of commercial formulations for these products.
The relative flammability of the TRIF sprays can be assessed by using a
slight modification of the Department of Transportation (DOT) Closed Drum Test
in the U.S. The 200-liter drum is laid on its side, with the open end closed
off with a film of plastic. A candle is lit at the bottom and the spray is
immediately introduced, using the test formula but a different valve more
121
-------
TABLE 37. TOTAL RELEASE INSECT FGGGER FORMULATIONS
INGREDIENTS
FORMULA A
(X)
FORMULA B
m
FORMULA C
m
Pyrethrum Extract - 20%
2.00
2.00
Piperonyl Butoxide; Technical
1.00
1.00
-
Emulsifiable Concentrate
-
-
8.00
Petroleum Distillates
12.00
12.00
7.00
Methylene Chloride
-
15.00
-
1,1,1-Trichloroethane
55.00
40.00
-
Deionized Water
-
-
50.00
Propane A-108
30.00
-
-
Isobutane A-31
-
15.00
35.00
HCFC-22
*
15.00
-
r
122
-------
compatible with the test procedure than the "latch open" type. The number of
grams of product sprayed into the drum until the Lower Explosive Limit (LEL)
"poof" is reached and recorded. From that figure, the number of cubic meters
that the dispenser can bring to the LEL composition is readily calculated.
Insect Repellents
The usual insect repellent is used to keep users from being bitten or
stung by various flying insects. The most common ingredient is N.N-Diethyl-m-
toluamide in concentrations of 15 to 30% of the total formula. Sometimes
other repellents are added for protection against insects only partially
repelled by the DEET active ingredient. They include MGK Repellent 11 and MGK
Repellent 264 and are offered by the McLaughlin, Gorraley & King Company, of
Minneapolis, MN (U.S.). A typical formula is shown in Table 38.
Variations on Formula Type 26 include replacing the hydrocarbon propel-
lant with 4.5% carbon dioxide, replacing the ethanol with isopropanol, and
removing the three MGK products, while increasing the level of DEET repellent
to about 30 percent.
The transfer efficiency from dispenser to skin or clothing is only about
55 to 65%, making other forms more attractive by comparison. Lotions and
sticks are available, as well as roll-on forms.
PHARMACEUTICAL PRODUCTS
These products are generally perceived as those that are inhaled,
injected, or otherwise inserted into the body to mitigate or control medical
problems such as migraine headaches, asthma, hemorrhoids, etc., or to provide
a contraceptive function, such as vaginal contraceptive foam. A few of these
products have already been covered in the foams area of this chapter. The
primary one that remains is the metered dose inhalant drug (MDID), which
represents a U.S. market conservatively estimated at well over 100,000,000
units per year and served by at least 28 brand-named products. As is common
with the rest of the aerosol industry, products are self-filled and also
123
-------
TABLE 38, INSECT REPELLENT FORMULATIONS
INGREDIENTS FORMULA
m
N,N-Diethyl-m-toluamide (95% A.I. min.) 20.0
MGK Repellent 11 - 2.0
MGK Repellent 326 1,5
MGK 264 1.5
S.D. Alcohol 40-2 (Anhydrous) 54.9
Fragrance 0.1
Propellant A-46 20.0
16 wt % propane and 84 wt % Isobutane
124
-------
contract filled. One or more self-fillers also contract fill for their
competitors. At this time, all of these products use one or more of the
following propellants: CFC-11, CFC-12, and CFC-114. The volume of pro-
pellants used is approximately 1,900 kilotonnes (4,200,000 pounds) in the U.S.
alone. Table 39 shows a typical published formulation. Others are suggested
in U.S. Patent literature and other documents.
Use of hydrocarbon propellants for some of these products is not satis-
factory because of production problems related to flammability, the oily,
stinging taste they have when inhaled nasally or orally, and their very low
density (considered from the standpoint of drug precipitation rates during
use) ,
CFG-11 is slurried with the drug and one or more excipient materials, and
this mixture is added to aluminum aerosol cans or bottles. They are then
fitted with a ferrule-type meter-spray valve which is hermetically sealed to
the container by a clinching or under-tucking operation. The CFC-12, some-
times mixed with CFC-114, is then introduced backwards through the valve.
CFC-11, with a boiling point of about 23°C, is unmatched by any other
nonflammable solvent of acceptable toxicology. Its replacement will neces-
sarily depend on the availability of one or more of the "future alternative"
HCFC and HFC propellants due to come on the market in 1992 or 1993.
For the 90% of MDID products that use very finely divided microcrystal-
line drug particles (averaging from 3 to 5 microns), it is important to have a
system of low solvency. Otherwise, the larger particles will get still larger
and the smaller ones (because of their higher surface energy) will get smaller
until they vanish. This disturbance will severely limit the product effec-
tiveness, Even with the optimum particle size distribution, the body's
defenses are such that only 7 to 12% of the drug reaches the target areas.
With the formation of larger particles in the container, this could drop to
below one percent.
125
-------
TABLE 39, BETA-ADRENERGIC BRONCHODILATOR FORMULA
Ingredients
g/10.5 g Can
Percentage (w/v)
Terbutalirie Sulfate (Drug)
0.075
0.714
Sorbitan Trioleate (Excipient)
0.105
1.000
CFC-11
2.580
24,571
CFC-1U
2.580
24.571 '
CFC-12
5,160
49.144
126
-------
The time frame needed for additional toxicological testing of the HFC arid
HCFC propellants, such as that being done in the Program for Alternative
Fluorocarbon Toxicity Testing (PAFTT)I, PAFTT II, and PAFTT III consortium
tests sponsored by the chemical producers, is one element of the new product
development. Another is actual formula and package development and specifica-
tions writing. A third is the opening of each company's "New Drug Applica-
tion" to the FDA, requesting an "Amended New Drug Application" (AJNDA). The
entire documentation is reviewed in such procedures, which typically take from
3 to 5 years to complete if there are no problems. One industry concern is
that the FDA may not have sufficient staff to process approximately 27
concurrent ANDAs with anything like their usual timing. These considerations
suggest that it would be to the advantage of chemical producers to cooperate
in their efforts to have new products cleared by the FDA within the generally
planned transition period ending about 2000.
The viability of new formulas depends on their solvency and toxicology.
Preliminary results from PAFTT will be released in September 1989. Because of
the uncertainty about HCFC-123, three possible formulas are suggested here for
consideration (see Table 40).
The use of HCFC-124 is optional, since it merely serves to reduce the
pressure slightly. The CFC-113 is used as an additive to the slightly
flammable HCFC-141b to create a nonflammable blend for slurrying purposes. If
the pharmaceutical firms and their fillers can handle a slightly flammable
slurrying agent (pure HCFC-141b), there will be no need to use the CFC-113 (or
CFC-11).
INDUSTRIAL AEROSOL PRODUCTS
There are numerous aerosols used only in industrial or institutional
applications. Two will be considered here: a lubricant spray for phar-
maceutical pill- and tablet-making rotary molding machines, and an industrial
127
-------
TABLE 40. METERED-DOSE INHALANT DRUG FORMULATIONS
INGREDIENTS
FORMULA A
(%)
FORMULA B
(%)
FORMULA C
(X)
Drug (as a microcrystalline suspension) 0.5
0.5
0.5
Excipient(s)
1.0
1.0
1.0
HCFC-I23
13..5
-
-
CFC-113 (or CFC-11)
-
4.5
-
HCFC-141b
-
9.0
13 . 5
HFC-134a
75.0 - 85.0
75.0 - 85.0
75.0 - 85.0
HCFC-124
10.0 - none
10.0 - none
10.0 - none
128
-------
adhesive. For the first application, the products must be nonflammable, and
leave only a Food Grade [Generally Recognized as Safe (GRAS)-Listed] residue
on surfaces to be contacted by the pharmaceutical pill or tablet. A current
formulation is shown below:
Rotary Tablet Machine Die Lubricant
Ingredients Formula (%)
Lecithin (Soy Bean source) 2.0
Sorbitan Trioleate 0,5
Ethanol (Anhydrous) 2.5
CFC-113 (Especially purified) 70,0
CFC-12 25.0
An intermediate step could replace the CFC-12 with a mixture of 10 parts HCFC-
142b and 20 parts HCFC-22, reducing the CFC-113 to 65 parts in the process.
This would reduce the CFC content by 32 percent.
When the future alternative propellants become available, the formula-
tions shown in Table 41 could be considered. Substantial testing of these
prototype formulas in Table 41 would be required as a prerequisite to commer-
cial use.
Adhesive Sprav
A typical industrial product is the adhesive used to coat automotive
gaskets before setting them in place on engine blocks or other equipment.
Aerosol products have a substantial niche in this market area. A typical
formulation is illustrated in Table 42.
129
-------
TABLE 41, ROTARY TABLET MACHINE DIE LUBRICANT FORMULATIONS
INGREDIENTS
FOBMULA A
FORMULA Ba
(X)
(%)
Lecithin (Soy Bean source)
2.0
2.0
Sorbitan Trioleate
0.5
0.5
Ethanol (Anhydrous)
2.5
2.5
HCFC-123
77.0
-
HCFC-141b
-
55.0
HCFC-124
-
30.0
HCFC-22
18.0
10.0
"Formula B could replace Formula A if HCFC-123 does not become commercially
available.
130
-------
TABLE 42. GASKET ADHESIVE FORMULATION
INGREDIENTS FORMULA
(X)
Isopropanol 10
Resin 8O-12110 • ¦ 5
Stabilite Ester Number 3b 5
Methylene Chloride 50
Xylenes 10
Propellant Blend A-70 20
"Made by the National Starch and Chemical Company.
bKade by Hercules, Inc.
131
-------
The product is sprayed onto the gasket while it lies on a waxed paper
other suitable substrate. After a minute or so, much of the methylene
chloride will have evaporated, bringing out the stickiness of the resins.
After another five minutes, the gasket is ready to be applied to the engine
block or other item.
132
-------
Part II - ALTERNATIVE AEROSOL DISPENSING SYSTEMS
133
-------
SECTION 1
INTRODUCTION
An imposing number of packaging alternatives to the standard aerosol
dispenser are available. Several use aerosol containers, but segregate the
propellant gas, and employ a finger-pump, trigger-pump, hand-operated piston
action, a metal spring, screw device, or other mechanism to dispense the
product or form the propellant gas within the container as required. Others
take the form of rather specialized, non-aerosol containers designed to enable
the user to create air pressure or product pressure, or to operate screw-on
finger-pump or trigger-pump metering valves. The pump-sprays, in all their
diverse forms, represent the most widely used alternative. .Such packaging
options as stick applicators, pads, etc. offer alternatives to the aerosol
system but do not provide sprays; these will only be briefly described.
A substantial number of aerosol alternatives will be described in Part II
of this report, beginning with those that are most similar to conventional
aerosols--and that may even be considered aerosols by various persons and
authorities — and continuing with alternate packaging forms that bear no
resemblance to aerosol products.
Definitions
The term "aerosol" was used by the scientific community at least as far
back as 1838 to describe dispersions of liquids in a gaseous medium, such as
fog, mists, and clouds, where the particles were true colloids, having
diameters of approximately 0.005 to 0.200 microns (fi).. Particles of this
magnitude were able to remain air-borne indefinitely. The smallest particles
are the same size as many larger molecules, such as starches, proteins, and
rubbers, and this part of the definition has not changed over the years. But
134
-------
the high end of the size range originally defined as the limit of microscopic
visibility, has changed greatly. The so-called "coarse aerosol" (to. the
physicist) now includes dispersions of particles ranging from 0.2 to about 20
microns (/i). Since the particle size distribution of commercial aerosol
sprays is generally in the 1 to 100 micron (/Li) range, at least some of the
sprays meet the expanded classical definition.
Some early definitions of aerosol products were based on particle size.
For example, around 1949, the U.S. Department of Agriculture (USDA) designated
that the "true aerosol" insecticide was one in which at least 80% of the
particles had a mean diameter of 30 microns (fA) or less, and in which no
particle could have a mean diameter greater than 50 microns (/i), To meet
these requirements, chemists had to design formulas with 80 to 85% or more of
propellant. The rationale was that the spray particles had to be very small
to remain airborne for two minutes to two hours to control flying insects.
The products soon became known as space sprays.
At about the same time, the USDA introduced the "pressurized spray"
concept for insecticides that were" slightly more coarse. The mass median
diameter of all particles had to be about 25/n, and some could be above 50/i,
Because the larger particles fell to the floor in less than one minute,
marketers had to use label directions that advised the user to spray an
additional 25-50% more product into the air space of rooms.
Finally, about 1951, the "residual spray" insecticide was defined.
Essentially all particles had to be larger than 50/i, so that such toxicants as
Chlordane, Strobane and DDVP (dichlorphos) would not be inhaled to any
significant extent. These were used only for spraying baseboards, doorway
sills, wasp-nests, and other inanimate surfaces.
The piston-pump insecticide sprayer could dispense dispersions of
particles about 25{M in size with deodorized kerosene formulations and those
20in size with the more flammable ethanol and isopropanol compositions. The
finger-spray and (later) trigger-spray insecticides generally provided
distributions of particles in the 30 to 80fi range. Consequently, much more
135
-------
had to be used for the control of flying insects, and the range of action was
also much less than that of aerosol dispensers.
The confusion between "aerosol" (the colloid sol) and "aerosol" (the
dispenser) has existed since the aerosol industry was born in 1943. In an
internal report, the Academic Press Inc. publishing house mentioned that more
copies of one of their new textbooks (Aerosol Science. G.N. Davies - Editor,
1966) had gone to recipients in the aerosol packaging industry than to the
Intended audience of physicists, physical chemists, and meteorologists, mainly
because of the lack of contents identification in some advertising and
promotional materials.. The industry made an attempt to rename itself as the
"Self-pressurized Dispenser Division" of the Chemical Specialties
Manufacturers Association, Inc. (CSMA) but the proposal was defeated. Today,
the words "aerosol" and "self"pressurized" product are used interchangeably.
For the purposes of interstate transportation, the U.S. Interstate
Commerce Commission (ICC), now a branch of the Department of Transportation
(DOT), defined the aerosol package in 1948 as follows:
"A sealed package containing base product ingredients, in which one
or more propellants is dissolved or dispersed, and fitted with a
dispensing valve."
Despite the fact that many self-pressurized products thought of as
aerosols do not strictly meet this definition, nearly all are currently
shipped under Section ORM-D of the tariff. (The definition has been modified
slightly over the years.) t
Other definitions are listed below without special comment:
CSMA Definition: "A pressurized sealed container with liquified or
compressed gases so that the product is self-dispensing."
FDA Definition: "A package consisting of a container and valve, into
which is added a base product and propellant, causing the dispenser to be
136
-------
under pressure, and able to discharge the product as a spray, foam,
liquid, gel, or other form."
H.R. Shepherd (Book) Definition, 1960: "A container whose contents are
expelled through an opened valve by means of the internal pressure of the
materials contained therein."
P.A. Sanders (Book) Definition, 1979: (Also used by CSMA) "A self-
contained sprayable product in which the expelling force is supplied by a
liquified gas."
National Paints and Coatings Association (NPCA) Definition: "A sel f -
contained package which contains the product and the propellant necessary
for the expulsion of the former."
British Aerosol Manufacturers Association, Ltd. (BAMA), 1971; "As
integral ready-to-use package incorporating a valve and product which is
dispensed by prestored pressure in a controlled manner when the valve is
operated."
Most of these definitions were created by one person, then approved by a
committee or by a brief committee action. Some are ill-conceived or outdated
and either do not cover all aerosols, or cover products not commonly denoted
as aerosols. In a recent inquiry to the DOT, a product consisting of a
mixture of Halon-1301/1211 (20:80) was finally judged to be a non-aerosol and
denied the standard aerosol ORM-D exemptions because it contained no base
product ingredients. Two materials other than propellant had to be present to
be designated an aerosol. The prospective marketer finally added a drop of
kerosene (a mixture of ingredients) to 13 Av.oz. (369 g) of the Halon blend,
and is now selling the product.
At a recent industry meeting, representatives from the Metal Box Division
(CMB) in England stated that they had persuaded British Aerosol Manufacturers
Association (BAMA) and the FEA (Federation of European Aerosol Associations)
in Western Europe that self-pressurized products placed in their "Bi-Can," a
137
-------
compartmented can containing an inner plastic bag for the base product, should
not be considered aerosols. This would give them preferred treatment by the
following transportation authorities:
• ADR European Agreement for the International Carriage of Dangerous
Goods by Road.
• RID International Convention Concerning the Carriage of Goods by
Rail (Berne 1961; Annex 1).
• IATA International Air Transport Association (Restricted Articles
Board).
• IMCO International Maritime Consultative Organization (United
Nations).
They asked for industry support in the U.S. No action was taken.
Another definition of an aerosol product that has often been published is
as follows;
"A hermetically sealed metal, glass or plastic container, fitted or
able to be fitted with a valve, and containing a base product and/or
a liquified and/or high-pressure propellant, able to dispense the
contents in a controlled manner as either a spray, foam, stream,
gel, paste, lotion, gas, powder or combination."
In the U.S., for the purpose of interstate transportation, aerosols are
limited to 50 cubic inches (819.35 mL) in metal cans, or to 4 fluid ounces
(118.28 mL) in non-metallic containers. The United Nations recommendation is
1000 mL for all products, and this is generally followed in Europe. In Japan
and other countries, the capacity limit is 1400 mL, although other
restrictions apply, A few countries permit "aerosols" up to 20 liters in
capacity if made of steel. In the U.S., steel cylinders up to 40 liters in
capacity are used for insecticide sprays, egg treating mineral oils, and other
138
-------
specialized applications. They are not considered aerosols. In some beauty
shops, hairspray concentrates are dispensed from pressure tanks maintained at
about 100 psig (7.04 bar) compressed air pressure at ambient temperature. The
operator uses a thin hose and breakup nozzle for product applications. These
products are also not considered to be aerosols.
139
-------
SECTION 2
DESCRIPTION OF AEROSOL PACKAGING ALTERNATIVES
BAG-IN-CAN TYPES
The Seoro Can
In 1954, Croce patented a perfume spray in which the perfume concentrate
and the propellant were contained in separate reservoirs (U.S. Patent
2,689,150). And in 1955, the Metal Box Company, Ltd. was granted a British
patent for a device that would permit the dispensing of flowable products
where the product and propellant were kept separate from one another (Brit.
Patent 740,635). In 1958, the Continental Can Company, Inc. formally intro-
duced their Sepro Can, which contained an accordion-shaped polyethylene
plastic alloy bag inside a specially designed aerosol can measuring 1 1/8" by
6 1/8" (53 x 156 mm). The unit was filled by first adding as much concentrate
as possible to the bag, then sealing the top with a one-inch aerosol valve.
After that, propellant gas was injected through a small hole in the base
section of the can and the- hole was plugged with a short length of rubber
cording. Only a few grams of propellant were needed to discharge from 175 to
<5
250 grams of product (according to its density), since the two were kept
separate by the bag. Also, the propellant would never be discharged during
the lifetime of the can, but would remain inside until the empty unit was
crushed, shredded, incinerated or rusted through in a dump site, except for an
infinitesimal amount that might seep through the plugged and double seam can
seals and escape into the atmosphere.
Cross-sectional views of the Sepro Can, a mechanized or pneumatic squeeze
tube, are shown in Figure 2.
140
-------
ACTUATOR
n i
VALVE
DOME
CAN
BODY
PROPELLENT
CHARGING
\x //
// N\
7/
// N\
' v- ¦ ¦ —y
« us
PROPELLENT CHARGING §
CHAMBER VALVE Q
Figure 2. The Sepro Can
141
-------
-The Sepro Can. from the term ."Separate Product and Propel1 ant." was
designed tq>permit gas-free dispensing and the dispensing of viscous products
that had 0 positive- yield point, .* Xt -was hoped that this package would
facilitate the growth of the "aerosol business by allowing a new range of
products to be packaged under pressure.
< The standard aerosol cannot dispense products with viscosities much
beyond 350,000 cps,. , since such chemicals and formulas usually have a positive
yield point, or, in other words, exhibit shape retention. For example, if a
toothpaste is filled into an ordinary aerosol can and placed under lOOpsig
(7.04 bar) of nitrogen pressure, an appropriate valve and spout will dispense
the produce very nicely, although some slight expansion of the extruded paste
may occur as dissolved nitrogen gas slowly forms almost', invisible foam bubbles
in the product. (This is too insignificant a feature to be observed by the
casual user.)
Within the aerosol can, however, each actuation causes a further cavita-
tion of the initially flat toothpaste surface. At a certain stage the cross-
section looks as shown .in Figure 3. The cavitation area will deepen with each
additional actuation, until it reaches the bottom of.the dip tube. ¦ At that
point the nitrogen gas will exit in a fraction of a second, and the remaining
product cannot be dispensed.
Toothpastes have been prepared without positive yield points, so that the
cavity left after each actuation will slowly heal--or flatten out. However,
they tend to drip off the toothbrush to some extent and will also leak out of
the valve spout orifice onto the top of the container. Some of the nitrogen
propelled (nitrosol) toothpastes of the early 1960s had spout plugs, connected
to the spout by a fairly thin polyethylene filament. They were designed to be
applied to the spout orifice after actuation, to prevent dripping. Sometimes
the pressure created by releasing nitrogen gas caused them to pop out. One
major marketer (Colgate) kept such a product on the market for about, twelve
¦ years,: selling 300,000 cans a year to persons who liked the dispensing system.
•142
-------
SPOUT
'ALVE
NITROGEN Y
GAS I aiPTDBI
Figure 3. Ordinary Aerosol Dispenser with Toothpaste
(About 15 percent Dispensed)
143
-------
But a slowly diminishing business of this small magnitude was unappealing to
Colgate and they finally dropped the item.
In the mid-1960s, the Continental Can Company developed and vigorously
promoted to marketers the following four Sepro Can sizes;
202 X 214mm (3-fluid ounce capacity)
202 X 406mm (5-fluid ounce capacity)
202 X 509mm (7-fluid ounce capacity)
211 X 604nun (16-fluid ounce capacity)*
* Never produced commercially.
A major detraction was the need for marketers to spend about twice as much for
Sepro Cans as for ordinary aerosol cans, as well as to install specialized
"gasser-plugger" and other equipment on their packaging lines. The package
also had a few quality problems. Except for "Edge," a patented gel-type
shaving cream developed by S.C. Johnson & Son, Inc. in 1969, no major uses
developed.
The evolution of the plugging technology went through several stages. At
first, a gasser-plugger would inject a liquified or non-liquified gas into the
filled can (1 to 7 g) and then ram the end of a 5/32" (4-mm) diameter lubri-
cated neoprene cord or rod into the 1/8" (3.2-mm) diameter hole in the center
of the can base. After insertion, the machine would cut the rubber cord off
from the rest of the reel,
These early machines, required to perform three fairly complex operations
in a sealed area, were production nightmares and generally the rate-limiting
factor in manufacturing operations. Much later, engineering improvements were
made to increase the viability of this sealing approach.
Then Continental Can Company announced an improvement known as the
Nicholson Model 2 plug valve. It consisted of a solid rubber billet or plug,
partly splined on the side wall, which was designed to fit part-way into the
144
-------
can hole during manufacture. In the filling operation, propellant gas was
introduced through the splined channels, after which a small ram was used to
force the plug fully into the hole, making an hermetic seal. This plug, with
only slight residual modifications, is still in use today.
The early plastic hag designs were highly pleated or accordion-walled,
and this caused problems when filling viscous concentrates such as pastes and
gels. The Continental Can Company purchased a single-head and twin-head Elgin
spin-filler, useful for filling these products, which they loaned to certain
marketers and larger contract fillers to help in product development work.
Larger machines, such as six- and twelve-head Elgins, were available. A very
large Consolidated Equipment Company eighteen-head filler was modified for use
by S.C. Johnson & Son, Inc. as a spin filler. Finally, the Pfaudler Mfg.
Company later introduced a six- and twelve-head spin filler. The Consolidated
and Pfaudler machines have a pressurized bowl option, for containing any
vapors from shaving gels that contained isopentane [ (CH3)2CH-CH2-CH3] or other
flammable or excessively volatile concentrates.
Every concentrate was found to have an optimum spin-filling rate,
generally in the range of 400 to 1200 rpm. Below 400 rpm, the centrifugal
force was often insufficient to effectively drive the concentrate into the
pleated areas, causing unwanted air pockets to form and survive. Over 1200
rpm, concentrate vortexing would exceed gravity and product would be spun
upward and out of the container.
During 1971, the products shown in Table 43 were being packaged in the
Sepro Can dispenser.
The labeled formulas for the "Edge," "Rise," and "Foamy" gel shave creams
are presented in Table 44, In accordance with Food & Drug Administration
(FDA) regulations, these cosmetic products must list their ingredients in
order of decreasing percentages; those present in concentrations of less than
one percent may be placed in any order.
145
-------
TABLE 43. PRODUCT MIX FOR SEPRO CAN DISPENSING
Brand Name Marketer Product Type Sales (MM Cans/Yr)
Edge
S.C. Johnson & Son, Inc.
Gel Shaving Cream
11,500,000
Crazy Legs
S.C. Johnson & Son, Inc.
Gel Shaving Cream, for
women
500,000
Shimmy Shins
Helene Curtis Industries
Depilatory
100,000
Shimmy Shins
Helene Curtis Industries
Moisturizing Cream
200,000
The Caulker
M.J. Jones & Company
Caulking Compound
Smal 1
Tomato Catsup
Ellis & Associates Inc.
Tomato Puree Catsup
Small
The Meat Eater's Sauce
(Georgia Firm)
Barbecue Catsup
25,000
Steiner's Jewel Gel
Steiner & Company
Ablative Insulating Gel
for Ring Repairs
20,000
Natural Honey
(California Firm)
Honey
35,000
Cook's Jolly Jelly
Cook Products Company
Three Jelly Products
30,000
Popcorn Oil
DeLorio & Associates, Inc.
Thickened Corn Oil; in
three flavors
25,000
Corn Popper Oil
(Florida Firm)
Soy Bean Oil, several
flavors
50,000
-------
TABLE 44. CTFA LABEL INGREDIENT LISTINGS FOR THE THREE GEL-TYPE SHAVE CREAMS
Edge
Ultra Gel
Rise
Super Gel
Foamy
Shaving Gel
Water
Water
Water
Palmitic Acid
Palmitic Acid
Stearic Acid
Triethano1amine
PEG-150
Oleth-20a
Pentaneb
Diethanolamine
Triethanolamine
Sorbitol
Myristic Acid
_ K
Isopentane
Fatty Acid Esters
Isopentaneb
Lauramide DEA
Isobutane
SD Alcohol 40
Is obutane
Cellulose Polymer
FDS.C Yellow No. 10
FD&C Blue No. 1
Fragrance
Acetylated Lanolin
Alcohol
Isobutane
Fragrance
PEG-90M
FD&C Blue No.1
Peanut Oil8
Mineral Oil3
t
Hydr oxye thylcellulose
Fragrance
Coco-triglyceride8
Menthol
FD&C Blue No. 1
D&C Yellow No. 10
aLubricants, used to seal in moisture,
bThe pentane and isopentane foamants are used in concentrations of about 1.4%
of the formula.
147
-------
The three formulas are quite similar. Each has the di- or triethanol-
amine ester of C14 to C18 fatty acids as the primary surfactant. Sodium and
potassium fatty acid soaps are absent, although they are always seen in
conventional shave creams. Cellulose, hydroxyethylcellulose, or high-
molecular weight polyethylene glycols are used to achieve the gel structure.
Most particularly, approximately 1.5% of low-pressure propellants are incor-
porated into the gel structure, so that the extruded gel can be "magically"
converted to a heavy foam on contact with the warm surface of the palm or
fingers or if touched and manipulated slightly. The original "propellant" was
CFC-113 (CC12F*CC1F2) , but after the FDA ban in 1978 the formula was converted
to use isopentane. Later, for a faster and more reliable transition, mixtures
of n.pentane/isobutane (80:20) and isopentane/isobutane (90:10) became
popular.
Around 1973, a regular shave cream called "Pour Homme" (For Men) was
marketed in a Sepro Can. The shave cream contained 3,25% of Propellant A-46
(which is 15 wt % propane and 85 wt % isobutane), and the "exospaee" (the
volume outside the bag but inside the can) contained Propellant A-60 (32 wt %
propane and 68 wt % isobutane). With a pressure ranging from 16 to 29 psi
higher than the product at 70°F (1.1 to 2.0 bar at 21"C), the product was
extruded at a reasonable flow rate, and since no propellant could ever escape
from the concentrate into an expanding head space, as happens with all regular
aerosols as they are used up, the foam density and overrun remained exactly
constant for "Pour Homme" during its service life. After two years, the
company was unable to obtain Sepro Cans to continue its operations and the
product was terminated.
At present, the Continental Can Division of U.S. Can Company, Inc. is the
only U.S. producer of this type of container. They have a capacity of 50 to
52MM units a year. The cans themselves are produced only on the firm's "Z-bar
TFS Conoweld I" line at their fabrication/assembly can-making plant near
Racine, WI. The line has a capacity of about 53 million units a year on a
ten-shift-per-week basis, and sub-assembly units, such as the pierced base
with loosely fitted plug, can be produced at only a slightly greater rate.
148
-------
The plastic bottle or "bag," as it is generally called, is made at the
company's Burlington, WI facility, using three "wheels" or individual produc-
tion lines, each having a capacity of 17.5 million units a year on a three -
shift, five-days-per-week basis. Originally, the-bags were made of either
polyethylene (LDPE) or of a particular "Conalloy" plastic alloy. The former
type has now been eliminated. The current Conalloy bag consists of low-
density polyethylene, nylon, and a proprietary binding agent produced by
DuPont that makes the two plastics more compatible. The Conalloy bags mold
better than LDPE types and have been used continuously since 1968,
While the discontinued LDPE had better resistance to moisture permeation
than Conalloy, the latter is superior as a hydrocarbon propellant barrier.
This characteristic became critical when Edge shave cream had to be reformu-
lated in 1978 to eliminate the internal CFC-113 foamant and the external CFC-
12/114 (60:40) blend (CCl^/CClF^CC1F2) in favor of isopentane and iso-
butane/propane (87:13), respectively. When hydrocarbon Edge formulas were
packed in Sepro Cans with LDPE bags, traces of immediate foaming were seen in
gels dispensed after as little as eight months of room temperature storage and
five months of 100°F (38°C) storage. In contrast, when Conalloy bags were
used, technicians could- not detect instant aeration until after 14 to 16
months of storage and the permeability did not escalate to a consumer problem
until the product had been stored 20 to 24 months at 70°F (21°C),
During late 1981, a 100% nylon bag became commercially available. It was
a stronger, tougher bag than the Conalloy type. It was pre - form or parison
molded at a substantially higher temperature than the Conalloy type, making it
possible to fill Sepro Cans with very hot products, and even to sterilize them
in an autoclave to the usual 252"F (122.2°C) if desired. After cooling to,
below 122°F (50"C), the Sepro Can may then be gassed and the bottom sealed.
Advantages of the nylon bag are that much less plastic is needed, and the
critical "T-tab" area at the bottom of the bag knits together very effectively
and reliably, like the earlier LDPE bags but unlike the Conalloy type, Voids
or thin spots have been a continuing problem of the Conalloy bags.
149
-------
During 1983, the "Lamicon" bag was developed for Sepro Cans, using a
Japanese process for the pre-form or parison blow-molding of multi-layered
plastics. The wall of the Lamicon bag is composed of LDPE/adhes ive/EVAc/
adhesive/LDFE, wherein the EVAc stands for ethyl vinyl acetate polymer. EVAc
provides an excellent barrier for oxygen and other gases. It has a good
record in food bottles, and Sepro Can tests show the same good performance.
It is also an excellent hydrocarbon gas and liquified gas barrier.
The Conalloy, nylon, and Lamicon bags can be effectively used with a
great variety of products, but there are reasonable limitations, as with all
packaging systems. Some are listed below:
• There may be problems with products whose viscosities are over
95,000 cps. (e.g., very thick molasses) at the discharge tempera-
ture :
Nylon will take up to about 350,000 cps, but transport rate
through even very large orifice valves may be slow.
Clayton and Super-Whip valves have "huge" orifices avail-
able, if inverted applications are acceptable.
Special Precision, Bestpak, and Beard valves are some-
times useful.
Increasing the propellant pressure outside the bag is useful,
up to the practical limit of 70 psig (4.9 bar) at 70°F (21°C).
In contrast, regular aerosols can only handle products with
viscosities up to 2,000 cps at room temperature.
• Products that exhibit pressure-induced syneresis:
The application of hydraulic or pneumatic pressure to some
liquid-in-solid products will cause the liquid to be partially
squeezed out of the matrix. An example is peanut butter, where
150
-------
the peanut oil can be sytierized out of the mixture, leaving a
substantially stiffer bottom layer. Initial ^experiments have
shown that regrinding the peanut fragments will reduce or
resolve the problem.
When ordinary peanut butters are packaged in Sepro Cans (using
nylon bags) the units operate well for the first few days, but
then deliver increasing amounts of peanut oil, and after all
this is discharged, the remaining paste is too stiff to
extrude.
Products that are highly lubricous:
A salad oil product can cause the rubber grommet and seal of
the Clayton valve to force out of the valve cup and fly across
a room. This does not occur with stem-type valves.
A silicone product managed to permeate the bag in micro-grain
amounts over many months, ultimately lubricating a nitrile
rubber plug to the degree that it poppe'd out of the hole in the
base section. Sepro Can storage at 122°F (50°C) exacerbated
the problem.
Products that are acidic:
Although vinegar (acetic acid based) products can be placed in
Sepro Can bags and used in connection with valve cups that are
laminated with polypropylene or lined with nylon, so that no
direct metal contact is possible, the contained acetic acid
(CH3'C02H) can permeate through Conalloy and nylon bags and
attack the tin-free steel (TFS) Conoweld I can surfaces.
Reformulation with malic or citric acids is useful in some
instances, since these do not permeate to a significant extent.
151
-------
• Clear gel products that may have long shelf lives before use:
Hydrocarbon propellants are able to permeate Conalloy and nylon
bags sufficiently to render gel shave cream products sub-
standard after 20 to 24 months at room temperature. The
problem seems to be strongly reduced if Lamicon bags are used.
• Certain solvents are capable of bag degradation. A solution that
included 64% turpentine slowly turned an LDPE bag into a semi*
viscous mass, and one with a vegetable oil did the same'at 122'F
s (5Q°C). Diethyl ether, an 8% sodium hydroxide oven cleaner base,
boiled linseed oil, and cyclohexanol all act to slowly degrade
nylons. The use of alternate bags is sometimes an answer.
• Products that must be hot filled:
None of the available systems will fail when concentrates are
filled up to about 145°F (63°C) and propellant is introduced at
any time thereafter.
If concentrates are filled between 145 and 160°F (63 and 71eC),
the propellant must be limited to isobutane, nbutane or their
mixtures, or over-pressurization will occur. Exception:
Higher-pressure propellants may be used if the hot concentrates
are given time to cool to 145°F (63°C) or less.
Above 176°F (80°C) the Conalloy and Lamicon bags may distort or
have a better chance of dissolving in certain concentrates.
Nylon bags should be used in such cases, since they can
withstand temperatures up to 280° F (138°C) with most con-
centrates .
Depending on bag size, bag composition, and, to a small extent, the
product itself, Sepro Cans will dispense from 94 to 97% of the contents within
the bag. The propellant outside the bag is not dispensed. In the U.S., only
152
-------
the dispensable amount of the product may be listed as the net weight. As a
rule, the Sepro Can operates with far less propellant than any standard
aerosol product.
Considering hair sprays, most conventional (single compartment) aerosols
use from 22 to 35% hydrocarbon propellant, or about 35% dimethyl ether
propellant in the formulation. For a corresponding Sepro Can of the 202 x 509
size, the amount of exospace propellant would be about 2% of the weight of the
concentrate. Some coarsening of the product would result from this transi-
tion, since the usual "micro-explosive" effect of the propellant evaporation
would be absent,
The Sepro Can may be operated in any position, since the bag is always
liquid filled. In fact, during the concentrate filling step, care should be
taken to fill the bag to the maximum, while allowing room for the valve
mounting cup insertion into the throat without overflow. Small air pockets,
when expelled, may sometimes make a "splat" noise and cause some products to
spatter. Fairly costly inverted or "spray-anyway" valve options are not
required for Sepro Cans.
As the product is used up, the bag collapses upward in a controlled way
because of the circumferential pleat design. No bag pinch-off will take
place. The latest pleat profile consists of gently rounded ""V"-shaped
indentations between 5/16" (8-mm)-high vertical wall sections. Compared with
the earlier, more sharply indented "V"-shaped pleats, the new bags provide a
more controlled collapse pattern, increased bag capacity and a generally
increased ease of filling viscous concentrates. A minor objection is that the
Sepro Cans become increasingly top-heavy during use, as the bag collapses
upward. This is most noticeable with dense concentrates such as toothpastes.
A special one-inch dome section is required for Sepro Cans, with the
opening enlarged from the usual 1.000 + 0.004" to 1.021 ± 0.003" (25,40 + 0.10
mm to 25.93 + 0.07 mm). This recognizes the approximately 0.10" (0.25-mm)
thickness of the Conalloy and Lamicon bags in that area, so that with bags in
place the net opening will be correct for the standard one-inch valve cups.
153
-------
In the case of the thinner nylon bags, an Intermediate can opening is
required.
The Sepro Can may be closed with any standard valve cup and standard
crimping tools; e.g., collet and mandrel (plunger). Standard 1.070 + 0.003"
(27.18 + 0.07-mm) crimping diameters may be used. However, the crimp depth
must be made larger, to account for the bag thicknesses at the crown and at
the point of hard contact. (Actually, both are crushed to thinner dimensions
in the crimping process.) Favored crimp depths are in the 0.180 + 0.004"
(4.57 + 0.10-mm) range.
The can uses a regular necked-in 201-diameter bottom, uniquely pierced
with a 1/8" (3,18-mm) hole in the center and having an upward lip or flange
projection into the can. The Nicholson Model 2, two-stage charging valve is
supplied by the can-maker and inserted to the first stage (loose) position in
the hole. The filler introduces the propellant through the valve's ports,
filling the area between bag and can. Depressing the valve to its second
position with a ram seals the propellant inside.
The fit between plug and can base is very efficient. The leakage rate is
always less than 0,50 g per year, and often less than 0.05 g per year at room
temperatures. Should severe over-pressurization take place because of
heating, the plug will remain in place even if the can eventually ruptures.
Sepro Cans are equivalent to other aerosol cans in terms of pressure
resistance. They can be hot-tanked at temperatures up to 170°F (77°C) if the
propellant is isobutane. During hot tanking, the contents of the bag do not
significantly warm up, since the gas-filled exospace and plastic barrier are
effective insulators. However, because of the pressure exerted on the can by
the propellant in the exospace, all DOT regulations are satisfied.
There is a wide choice of propellants in the U.S. The usual ones are
isobutane or lower-pressure blends of propane/isobutane. Dimethyl ether might
act to soften the bags. For two reasons, the high-pressure compressed gases,
-------
carbon dioxide (C02) nitrous oxide (N,0) , nitrogen (Ns), and ethane (GH,*CH,)
are not appropriate; ... :
There is no reserve against slow leakage. (In the case of liquifi
propell ant s , a snial 1 1 i cjuid pool l s present to x@ pi ace lost propel ~
lant gas by evaporation);
Pressures will diminish 'substantially as the bag slowly collapses
during product use because the absolute pressure varies inversely
with headspace or outage space volume. This can be shown by the
following example;
The volume of the exospace is 40 mL. The initial pressure of
carbon dioxide is 115 psig. After 80 mL of product has been
expelled (about 1/3 of the total), what is the remaining
pressure?
Initial Pressure is 115 + 15 <-= 130 psi-absolute
"Final - pInitial * ?Final/vInitial) =*43.3 psi-
absolute
Final Gauge Pressure - 43.3 - 15.0 = 28.3 psig
The example shows that such propellents are unable to dispense
the entire contents of Sepro Cans.
Practical propellants for Sepro Can gassing are the hydrocarbons:
nbutane, isobutane, and propane, or their blends. Establishments unable to
safely fill hydrocarbon propellants may wish to use .such blends as HCFC-
22/142b (40:60) for non-food items. As product viscosity increases, higher-
pressure [up to 70 psig at 7Q°F, (4.9 bar at 21°C)] bl-ehds- of butanes/
propane may be preferred. The action of Clayton,¦ Super-Whip,; and other stalk
type toggle valves can be stiffer at these; higher pressures because of
resistance factors. " #
•* 155 - , . "
-------
Sepro Cans are presently being made on only one production line in the
U.S. It has a speed of 240 units per minute and averages 110,000 units per
shift. It is scheduled to run at a maximum of three shifts one day, two the
next, three the thxrd, and so forth, a1low i_ng for maintenance durin^ the thxrd
shift on every second work day. Considering 200 days of operation a year, the
output is 52,000,000 units a year.
Changeovers, from the standard 202 x 509 size to the 202 x 314 sample
size, for example, are very costly to the supplier, requiring about 5 days of
downtime for both the can-making and bottle-making plants, and a similar
period to change back. It would,take¦an order of 5 to 100 million cans for
this to be feasible, and the can-maker has so far sold all sample cans to
marketers at about twice the usual discounted prices.
Quality problems that caused S.C. Johnson & Son, Inc. to reject as many
as 30% of all "Edge" Sepro Can pallet loads during 1980 and 1981 were reduced
to a 0.281 reject rate in 1984 and to a 0.21% reject rate in 1987. The
quality problems included the following;
• Welding faults--lack of integrity due to the presence of cold weld
areas on the can side seam.
• Crimp problems--lack of integrity due to offset parting lines on the
bag neck lying against the curl of the can. Since the bag-to-curl
interface has to seal pure hydrocarbon gas, with no solvent action
to soften or swell the plastic--to help create a more effective
barrier--offsetting is a very serious consideration. The offset
distance is tightly controlled and measured frequently during bag
production.
0 Incompletely molded rubber grommet. Grommets are made on a complex,
98-cavity mold, and sometimes the rubber fails to fill the entire
volume of each cavicv.
156
-------
Weak tail tab on the base of the bags. Presently a thicker (and
thus stronger) knit line is used, together with a recessed construc-
tion.
• Top seam problems. The top double seam cannot be tested during can
production for hermetic integrity, because of the bag. For example,
welded end cracking has caused problems in this area.
Despite the manufacturing complexities of the overall Sepro Can package,
the Continental Can Division currently feels that it produces a very high-
quality item, partly because of the insistence on quality by customers.
The 1989 pricing of Sepro Cans of standard size is as follows:
100.000 Units 500.000 Units
Base Price $360.34 $360.34
Coat/Print/Varnish (Outside) 9.89 9.19
Each Additional Print 3.14 2.61
White Dome 2.60 2.60
White Bottom 1.64 1.64
In 1989, there were reportedly twelve marketers or contract fillers in
the U.S. who were capable of filling Sepro cans. All but two or three have
relatively low-speed Terco, Inc. gasser-plugger equipment, generally rated at
40 cans per minute. One filler (Aerosol Services, Inc., City of Industry, CA)
has two such lines.
Since 90 to 95% of the present product mix is the post-foaming, gel-type
shave creams, where the concentrate contains 4 to 5 volume percent of very
volatile hydrocarbon material [typically isopentane, boiling at 86°F (30°G)],
concentrate preparation and filling can be dangerous. The major filler, S.C.
Johnson 6e Son, Inc., chills the concentrate (without hydrocarbons) to around
38"F (4"C) in a closed system, after which the hydrocarbon blend is added.
Because of the low temperature, foaming 'is avoided, even when agitation is
applied. The finished concentrate is filled into cans under explosion-proof,
157
-------
well-ventilated conditions. Other methods meter the concentrate and hydrocar-
bon portions together under cold conditions just before the filling step. The
option of adding the gas-free concentrate, and then the pure hydrocarbon
blend--or of adding the gas-free concentrate, crimping on the valve, and then
pressure loading the pure hydrocarbon blend--is seen as a possible alternative
for less gel-structured formulations. These "looser" dispersions would allow
intermingling of the hydrocarbon liquid within a reasonable number of days or
weeks. Since the bags are completely full, hand or mechanical shaking of
finished units is of relatively modest benefit. The process is best served by
filling the concentrate (gas-free) in very warm 122"F (50°C) conditions,
adding the foamant gas by Through-the-Valve (T-t-V), hot-tanking, and then
mechanically shaking cans or cases of cans at the end of the line. The 1989
prices for several Terco, Inc. machines required for these functions are shown
in Table 45.
The present sales outlook for Sepro Cans is uncertain. Post-foaming gel-
type shave cream marketers are studying the option of a piston version of the
same can size, and one has market-tested the concept. Because of the high
price of the Sepro Can and the availability of improved versions of the piston
can in both tinplate and aluminum containers, most of the limited activity in
this field centers in the piston area.
Bi-Gan
Around 1987, after extensive research, the Sutton Aerosols Unit, Metalbox
Aerosols & Toiletries Packaging Division, MB Group, p.I.e. (England) launched
their version of the Sepro Can. Except for a longitudinal bulge, their nylon
bag fits snugly to the can body, leaving only a 1/8" (3.18-mm) high space at
the top and a somewhat larger volume at the bottom for the exospace propel -
lant. Several can sizes are available. One is 115/114-200 x 515 (50-mm
inside diameter by 150-mm inside wall height), while another is 112/113-114 x
312 (45-rnm i,d. x 95-mm i.w.h.).
158
-------
TABLE 45. PRICES FOR TERCO, INC, GASSER-PLUGGERS (1989)
Production -Rate®
Type Operation
Cost (Dollars)
40 c/min.
Rotary Indexing
$26,063
40 c/min.
In-line
$45,758
80 c/min.
In-line
$56,355
120 c/min.
In-line
$77,040
120 c/min.b
In-line
$88,600
"Bottom charging and plugging unit only, except as noted.
bBottom charging and plugging unit, plus through-the-valve gassing of
hydrocarbon foamant.
159
-------
The standard closure is a 3.5-mm pierced hole in the base, which is
sealed by a short length of 5.0-irna diameter 80-Durometer nitrile cord after
propellant injection.
Before the formal introduction of the Bi-Can at the Interpack trade show
in Dusseldorf, West Germany, Metalbox worked with Aerosols International, Ltd.
(England's largest contract filler) for over two years getting them ready to
produce Bi-Can products on a medium-speed line having a capacity of about ten
million units a year. During 1988, the line actually produced about 3.5 mil-
lion Bi-Can units. As in the U.S., nearly all the business was in the popular
post-foaming shave cream gel area, with products by Gillette (well over two
million units), Wilkinson Sword, Tesco, Marks & Spencer, and Medicare.
The Bi-Can (short for "Bag-In-Can") is now being promoted for additional
applications, including "Nappi" coffee concentrate, two toothpastes, a line of
artist's pigments, petrolatums, lithium greases, catsup and mustard, jellies,
medicinal liquids, soft- to medium-viscosity caulking compounds, syrups, honey
and flavored honeys, medicinal liquids, and cake icings. Baby oils and skin
lotions have been demonstrated to customers.
Were it not for the high cost, and sometimes the relatively small size of
the package, bag-in-cans might be a very high-volume item. The ability of
these units to c o n t a in and deliver products is summarised below.
• Can deliver, as well as contain;
• Cannot be spilled;
• Can be made sterile by autoclaving, and will remain sterile during
use \
• Csti I)© psclcedl essentially sir fxree for ingredient, stability;
• Can handle liquids with viscosities of 1 to 1,000,000 cps. at
ambient temperature;
160
-------
Can be packed and maintained moisture free (important for moisture -
polymerized functional organo-silicones, for example);
Are not messy to use;
Are highly directional in application (controlled spray);
Can be used with container in any convenient position;
About 98£ of the contents can be dispensed--more than many other
packs;
No risk of product contamination by metals, except stainless steel
valve spring (The Metalbox "Metpolam" laminated valve cup may be
needed);
Highly concentrated product forms can be dispensed;
With proper propellant selection, such as nbutane, the package can
safely withstand temperatures up to 212"F (lOO'C);
Applicable to post-foaming gels, as are the related piston-can and
Enviro-Spray bag-in-can packs;
No concentrate evaporation is possible;
The propellant is only 1 to 2% of the total contents for most
products and is likely to be incinerated with the empty can;
Can dispense product as a spray, foam, post-foam, liquid, paste, or
gel;
Available in 3- to 9-fluid ounce (30 to 226-mL) bag volumes;
161
-------
• Bags with as many as four different-materials in up to four layers
(including aluminum) are available for maximum resistance to
permeation, ensuring shelf lives of at least three years in tests to
date;
• With the better bag shape and improved filling techniques, thick
items can be filled without refrigeration or spin-filling options;
• Low-pressure mixtures of special properties may be packed, such as a
water and dimethyl ether mixture, which provides high solvency and
soon evaporates completely;
• The package is triply tested: during can-making, when the bag is
inserted, and during the bunging or plugging operation;
• A wide range of delivery rates is available, depending on choice of
product viscosity, exospace propellant pressure, and valve orifice
sizes; and
• A total of 23 "Trimline" sizes are potentially available, from 100
to 1,114 mL.
Metalbox, now actually CMB Packaging, Ltd., formed by the merger of
Groupe Carnaud, S,A. and Metalbox Packaging, Ltd. in 1989,, declares that the
Bi-Can is not an aerosol. This view is upheld by the British Aerosol Manufac-
turers Association (BAMA), and several European regulatory bodies (such as
COLIPA) that have published conclusions on this subject. Bi-Cans are pre-
sently being shipped within the United Kingdom as non-aerosol commodities.
Compack
Around 1973, Aerosol Services Moehm, S.A. of Switzerland (now ASM, S..A.)
developed a Lechner™ aluminum aerosol can with a LDFE vertically pleated bag
and a valve cup lined heavily with plastic. Several sizes were offered, with
diameters of from 1 3/8" to 2 1/8" (35 to 52 mm). Product leakage at the '
162
-------
complex interface of can bead, bag flange, and valve mounting cup was a
problem. Products such as Blendex toothpaste and a paste-type shampoo
concentrate lost marketshare and this forced the company to look for refine-
ments ,
Alucompack
This bi-compartmented aerosol used a very thin aluminum tube with a flat
base and flanged top as the inner container. This eliminated the gas permea-
bility that had plagued the previous design, the LDPE bag. Also, if the
system was combined with a seal of epoxy resin at the crimp area, using air as
the propellant, it offered a three-year shelf life, guaranteed by the sup-
plier .
The inner tube, or "Alu-Bag," of D-l (Heat-Killed, minimum temper)
aluminum was generally 0.992 + 0,003" (25.2 +0.08 ram) in diameter and
typically 6" (151 mm) long, or about 1/2" (12.7 mm) shorter than the outer
aluminum can. Under the 3/32" (2.4 mm) top flange there is a thin neoprene
rubber gasket, which is the area that can be improved by sealing with epoxy.
The valve cup is fitted with 0.040" (1.00 mm) neoprene or buna-N rubber
gasket, called a cut (or lathe cut) cup gasket, since this affords a more
reliable seal than the Weiderholder or other Flowed-In, water-based neoprene
gasket types.
The aluminum inner tube offers more resistance to pneumatic crushing than
its plastic counterparts; therefore, it is necessary to use a fairly high-
pressure propellant in the exo-space between tube and can. At least 2-8 psig
(2.0 bar) of pressure differential should be available or dispensing will be
incomplete. The aluminum tube is (rarely) susceptible to a kinking type
compressive distortion; therefore, it is useful to insert a length of polypro-
pylene capillary tubing in it before filling with the concentrate. Typical
dimensions are 90 to 95% of the length of the tube and 0.090" o.d. by 0.060"
i.d. (2.29 x 1.52 mm).
163
-------
The i.d. of the outer can Is typically 30 to 35 mm, which means that the
volume.of the exospace is greater than that of the inner tube or bag. Air or
nitrogen pressure can then be used, and the pressure will not decrease
substantially during tube collapse, unlike the situation with Sepro-Cans and
Bi-Cans. Since less than 1.0 g of air or nitrogen is used, the degree of
hermetic sealing must be very good.
The Alucompack development was used for toothpastes, a caulking compound
for bathroom crack and crevice filling, and three medicinal items. Aerosol
Services, A.G. performed the filling. They developed a technique of adding
hydrocarbon propellants, first strongly cooled, into the outer can.
Of the 3 to 4 grams poured into the can, perhaps 1.0 to 1.5 grams
evaporated before the evaporation stopped. Meanwhile, the inner tube, smeared
with epoxy, was slid through the one-inch (25.4-mm) opening and quickly filled
nearly full with product. The capillary tube was inserted. The valve,
without dip tube, was placed in position and hermetically sealed. When
pouring isobutane, propane, and their mixtures into cans, these dispensers
were never filled outside of Europe. Approximately 1.7 grams of liquid
hydrocarbon are released when Under the Cup type gassers release aerosol cans,
and this is the major charging method employed in the U.S. and Canada.
Micro-Coiroack
The third variant, by ASM of Switzerland, is a smaller version of the
Alu-Compack, generally holding about 10 to 15 mL of product. Such products as
a "small area" depilatory (for facial hair, moles with hair, etc.), an anti-
wrinkle (Retin A) cream, and various medicinal ointments are filled in these
small dispensers. The 13- to 20-mm diameter ferrule-type valve is attached by
standard 18- to 24-tine mandrel clinching techniques.
164
-------
Lechner ("Types I Through IV)
The Lechner GmbH System I can was developed around 1974 and consisted of
a vertically pleated LDPE bag in an aluminum can, sold with or without a
nitrile rubber plug in a 3.5-mm hole in the base. The filler can pressurize
and seal the can with a gasser-plugger machine, or, with the plug in place,
with a syringe needle that penetrates the plug. The Aerofill, Ltd. firm in
England is one supplier of syringe gassers; they claim their hardened steel
needles can last for filling up to 60,000 cans. The needles are eventually
weakened by dulling and abrasion from the filler substances in the nitrile
rubber plugs.
System I is limited to LPDE, and (now) HDPE (D1018) bags in seven sizes
ranging from 50 to 400 mL. Such products as antiseptic sprays, household and
car cleaners, medicinal and veterinary products, contact lens cleaners,
disinfectants, depilatories, and air fresheners have been sold in these
packages. Despite the sales efforts of Lechner USA Ltd., nearly all these
products are sold only in Europe.
The System II dispenser has been more successful. It uses an inner
aluminum bag and outer aluminum can, with top double seam and a dome that may
be either aluminum or tinplate. The extruded, cut off and flanged outer can
and inner bag are fitted together and triple seamed to the dome. It uses base
gassing as described for the System I unit. Introduced around 1978, it is
available in 14 sizes (18 bar), two at 15 bar (217.5 psig minimum burst), and
one at 12 bar (174 psig). The last size is the largest; 502 mL, which was
originally conceived for holding highly acidic hair coloring paste and for use
with very high-viscosity silicone-based caulking compounds for commercial
uses, but it is now used to dispense a wide variety of products. One inter-
esting use for both this and the Alu-Compack is as the power unit for a nail
dispenser. A particular gas blend of allene and methylallene, having a
pressure of 90 psig at 70"F (6.33 bar at 21°C), is filled to a capacity of
100% into aluminum bags surrounded with propane, which has a pressure of 108.5
psig at 70eF air free (7.64 bar at 21°C). A micro-metering valve located
outside the can feeds a tiny amount of "MAPP Gas" to the firing chamber of a
165
-------
very small spring-loaded ram cylinder when a triggering mechanism is pressed.
A minuscule spark plug explodes the mixture above the piston-ram, and the ram
then moves outward to drive in a nail, separated from a nail-pack and held in
position below the ram. In this way, nails can be driven into wood as fast as
one can pull the trigger. . A 3.99-fluid ounce (117.98-mL) charge of MAP? Gas
can sink thousands of nails.
A number of topically applied medicines and drugs are under test in
small versions of the System II dispenser. The 3M, Inc. firm uses it for
their fuel injector engine cleaner, since it is important that only the liquid
phase enter the engine for spark plug and upper cylinder area cleaning
purposes. Prescription dental gels and gum cements are conveniently dis-
pensed. One new drug under development in Europe requires autoclaving at
275,4aF (135°G). After the filled System II unit is processed, heated, and
cooled, it is gassed and plugged.
The Lechner System III dispenser consists of a conventional aluminum can,
but heavily lined in such a way that the lining adheres tightly only at the
crimp and upper dome area. The rest is very loosely attached. When the can
is filled with concentrate and sealed, gas is injected through the hole in the
bottom, causing the bulk of the lining to separate from the can surface and
become, in effect, a bag. The base hole is then plugged. (Syringe filling
cannot be done for fear of perforating the adjacent bag material.)
The modified polyolefin lining is suitable for a wide range of products.
In fact, virtually any cream, gel, lotion, ointment, paste, or liquid now
packed in a plastic tube or bottle can be more conveniently packed in the
System III, At least 98% will be discharged.
Finally, the Lechner System IV is a modification of the System II, that
improves on the relatively poor aesthetics of the triple-seamed dome design.
It looks like a standard aluminum (one-piece) aerosol can. The larger version
with a 1" (25.4-mm) opening will be available by October 1989, and smaller
ones, using a 20-mm ferrule type valve, will come onto the market about March
166
-------
1990. They will have a 0,98" (25-mm) diameter at first, but other diameters
will be available later on.
The most significant of the Lechner developments is the System III
dispenser, since it eliminates the preformed bag as such, and thus eliminates
about a third of the component cost. This considerable economy should do much
to stimulate volume growth of the two-compartment dispensing system.
Fresspaek
In 1976, this vertically pleated medium density polyethylene (MDFE) bag
in aluminum or tinplate can development was completed by a West -German firm in
Hamburg. By the following year, two West'German and one French firm announced
they were ready to supply it commercially. However, because of seepage
problems around the crimped seal (especially in the case of the aluminum
cans), the dispensers were sold in relatively small quantities for about two
years and then discontinued.
Other Bag-In-Cans
A number of additional bag-in-can designs have not achieved commercial
success, sometimes in spite of excellent designs. One of these, developed in
California and taken over by the (then) American Can Company, used a "cup" of
polyethylene or laminate structure, attached via the top seam of a regular
tinplate can. Production problems consisted of trying to uniformly air blow
the plastic cups into waiting "domeless" cans, and trying to eliminate the
"Z"s or "switchbacks" that occurred over the flange. When these triple
thickness areas of plastic were wrapped into the top triple seam, actually a
sextuple seam resulted, which leaked slowly or latently at the fold inter-
faces. The companies eventually halted product development.
167
-------
PISTON CANS
As with the Sepro can, this compartraented package requires less pro -
pellant than a conventional aerosol package. Probably the first commercial
piston can was developed in 1961; It contained about 4 Av.oz. (113,4 g) of
Brylcream in an aluminum two-piece container with a free piston of medium-
density polyethylene (MDPE),
Until about 1988, there was only one piston supplier in the U.S., the
American Can Company (how the American National Can Division of Pechiney,
S.A.), who supplied a two-piece aluminum Mira-Flo container. There are
several in Europe and at least one in Japan.
During 1974, a drawn-and-ironed two-piece steel can was manufactured for
the U.S. Borax and Chemicals Company's "Boraxo" waterless hand cream. The can
was a seamless steel type, with top double seam. The problem with soldered
and other welded side seam steel cans was that the polyethylene pistons could
not fit the can wall snugly in this side-seamed area, and this caused "blow-
by" of the gas past the piston wall and into the product, where it usually
dissolved and lost its pressure, In fact, aluminum cans with wall dents were
probable candidates for blow-by problems. During 1986, innovations in side-
seal technology created the smooth side-seara profile, improving on earlier
constructions of the "stepped" type.
The tinplate or tin-free steel (TFS) cans are probable candidates for
piston can modification. They are approximately 20% less costly than aluminum
and are available in sizes of 100-mL to 1114-mL total capacity. The metal is
also harder and less vulnerable to pre-filling or post-filling denting
problems.
The Mira-Flo Can
Experimental piston cans date back to 1956, when Crown Cork & Seal
Company used a crude piston, over a large, compressed, steel spring to
dispense various food products from their 202 x 406 Spra-tainer can. The
168
-------
spring provided backup pressure in case of propellant leakage. American Can
Company began work on a two-piece 202-diameter aluminum can about 1960, and in
1962 they introduced their Mira-Spray (single compartment) and Mira-Flo
(piston-type) 202 X 406 containers. The Mira-Flo had a 9/64" (3.57 mm)
punched hole in the base, suitable for gas injection followed by plugging with
a cord of 70-Durometer neoprene rubber.
The new cans were made at a plant that had an initial capacity of
38,000,000 units a year. Since the price of the Mira-Spray can was somewhat
higher than that of the highly similar, steel, two-piece Spra-tamer made by
Crown, sales were very poor.
American Can Company promoted the Mira-Flo cans, which were made on the
same production line as the Mira-Spray cans, except that an LJDPE piston and
pierced base section were inserted. Samples containing domestic and imported
cheeses were shown to Kraft, Nabisco, General Foods, and others from 1961
through 1963, Samples containing oleomargarine and thick chocolate syrup were
shown to Mazola and Bosco product managers at the Best Foods Division of CPC
International Inc. An experimental margarine sample, prepared at the American
Can Company's Barrington, IL Research Center for the Land 0 Lakes Co., Inc.
survives today, works well, and still contains product that has a good, fresh
taste after 27 years.
After a few years, the capacity of the production line was reached:
approximately 1,000,000 Mira-Spray cans for various small uses (such as air
fresheners), 33,000,000 Mira-Flo cans with various types of cheese, and
4,000,000 Mira-Flo cans with various colors of Fillsbury's Cake Topping for
creating decorative designs and/or messages on cake icings. The toggle-action
Clayton Corporation food valves were supplied with several alternative
actuator tips (in the case of the cake toppings) to create extrusions with
star shapes, ovals, etc., in addition to the standard round ribbon. Instead
of the more costly aluminum option, American has turned to the welded tinplate
piston can.
169
-------
While many fairly complex piston profiles have been developed (mainly in
Europe) over a thirty-year period, in 1987 American pioneered the "free-
floating type; a piston that had to expand slightly to reach the can walls.
It requires the product to have a viscosity of over 12,000 cps at ambient
temperatures. The novel pistons use a "gasket" formed by the product itself
to effect the seal and inhibit gas by-pass.
The second innovation was commercialized in late 1986. Known as the
"umbrella valve," it is a form of rubber plug shaped like a mushroom. It is
applied from inside the can bottom. Small ears prevent the plug from being
pushed into the can. The larger umbrella top is flexible enough to compress
upon insertion. Once the plug is in the can, the internal pressure forces it
downward, making a tight seal. The new valve allows filling speeds of up to
360 cans per minute.
Disadvantages of piston cans are that they require products of reasonably
high viscosity that do not distort the piston. Piston by-pass (or blow-by)
and permeation can cause problems by reducing the quantity of gas below the
piston and perhaps by causing foam generation in the product. If the product
is not compatible with the can, this can be a bigger problem with piston cans
than with bag-in-can types because of the direct exposure of can surfaces to
the product. New, very heavy linings are being developed by CMB Products,
Ltd. and others to counteract this shortcoming. Some of the linings are
bonded polypropylene approximately 0.010" (0,25 mm) thick, and they can also
be used for the double seam sealing material.
Other Piston Cans
Piston cans using aerosol containers have been marketed by Advanced
Monobloc, Ltd. (Division of CCL Industries, Ltd., Toronto, Canada), the
Continental Can Group of United State Company, Inc., Boxal/Alusuisse,
Cebal/Pechinery, S.A., Hoe11, GmbH (Hamburg, West German), Rocep Pressure
Packs, Ltd. (Glasgow, Scotland) and a firm in Japan. Except for the Rocep
units, most are typical piston cans and conform to the description of "Mira-
170
-------
Flo" units. Perhaps the largest manufacturer is the U.S. Can Co., since they
now have a considerable share of the shave cream business.
Rocep cans are unique in that they are often quite small, such as 1" (25
mm) in diameter, and sealed with a 22-mm type ferrule valve. However, the
main difference from others is that they use a double pistons two rather
shallow types, one below the other, with the small space in between filled
with mineral oil. The purpose of the oil is to capture and retain any
propellant that penetrates through or around the lower piston, so that it will
not go further upward and get into the product. Another unique feature is the
"lever pack" package design, where the valve turret head is turned varying
degrees on an eccentric track to control dispensing rates. Dispensing can
then be actuated at various rates by depressing a 3 to 4" (76 to 101 mm) wire
profiled lever against the can. This type of control is perfect for sealants,
among other products.
Silicone acetate or silicone aminofunctional caulking compounds, which
turn to a rubbery mass when brought into contact with humidity or moisture
illustrate this product type. These products cannot be allowed to contact the
liquified propellant or various degrees of foaming would take place as they
were dispensed, leading to a strange-looking and less-effective seal. Under
such trade names as "One Tough" Silicone Sealant blister packs containing
three-ounce (80-g) piston cans are being sold at $5.95 to §6.95 each.
Standard trigger-type caulking gun packs with twelve times as much of the same
product are sold for $4,00 to $4.50 in the same stores.
An interesting alternative to the piston can is a pressurized pack
designed to clamp onto one end of a standard caulking canister, filled with
organo-silicone, acrylic, butyl or thiokol sealing compounds. An independent
plastic piston is pressed into the cylinder by finger-pressure on an actuator.
When the finger pressure is released, the gas pressure is automatically
discharged upward, out of the orifice in the actuator. This instantly stops
the flow.
171
-------
The Rocep package uses a nonflammable mixture of HCFC«22/142b (40:60) for
a pressure of about 83 psig at 70°F (5.85 bar at 21°C), including the partial
pressure of trapped air,
A major problem developed when the relatively high pressure and solvent
action of the propellant blend softened and squeezed the neoprene plugs out of
the pierced holes in the tinplate can bottom, thus depressurizing the units.
Short of using CFC propellants, there is no lower-pressure, nonflammable
propellant currently available. The issue was finally resolved by moving to a
slightly thicker nitrile plug and punching the hole in such a fashion that a
slightly ragged lip was formed at the inner rim of the hole to act as a barb.
Even so, extended storage at 130°F (54,4°C) will cause expulsion of the plug.
Recent findings suggest that a trace film of mineral oil (from between the
pistons) is a contributing factor.
The final difficulty with this package is that the container itself is
composed of a special aluminum top and wall extrusion, but the base is of
tinplate. An uneasy junction of these two metals at the bottom double seam is
produced after the silicone product and double piston assembly are added. The
tinplate tends to cut into the much softer and thicker aluminum, resulting in
a 6.2% leakage rejection rate at the factory hot-tank tester. Technology
exists to double-seam dissimilar substances, even plastic container walls to
tinplate end sections, but it is not very effective for small-diameter
closures such as the 1" (25.4-mm) diameter container.
Apart from the silicone-based specialty bathroom tub and tile sealants
just discussed, no other products have yet been commercially produced in this
packaging form. The high production.cost, partly due to high scrap rates, is
considered to be a major factor.
The Boxal Pump Dispenser
During the International Packaging Exhibition (Pakex 89; Birmingham,
England; April 21, 1989) the Boxal Group, a member of Alusuisse Packaging
172
-------
Division, showed their standard piston-type aerosol can, as well as a new,
propellantless version that operates on a vacuum suction principle.
Using a custom-made valve by Coster, S.A. and a standard aerosol-type
aluminum can with inner piston and perforated bottom (but no plug), the unit
provides a metered flow of product whenever the actuating spout is operated.
Lotions, creams, and pastes may also be dispensed.
When the pump actuator is depressed, a low vacuum is created in the
product compartment. Through the hole (1/16" or 1.6 mm) in the base, atmo-
spheric pressure then presses the HOPE piston upwards a small distance. The
pump is constructed to prevent any contact between product and air until the
material is discharged from the dispenser.
The pump stroke volume can be adjusted according to product characteris-
tics and according to marketer requirements. Partial strokes will extrude
correspondingly less product than full strokes. Because the pressure differ-
ential (between a partial vacuum and normal air pressure) is relatively low,
the unit is not suitable for highly viscous products. They would emerge too
slowly for customer satisfaction.
The development is not inexpensive, due mainly to the cost of the
specially designed Coster, S.A. pump-action valve. It does provide a new and
attractive packaging form for creams, gels, pastes, lotions, and other low-to-
medium viscosity products in the cosmetics, toiletries, pharmaceutical, and
food areas, usually giving those products prolonged shelf lives in comparison
with packaging in jars or bottles. Evaporation, air oxidation, fragrance
deterioration, spillage, and breakage are all avoided. The products can be
filled on standard aerosol equipment at high speeds, From 96 to 97,5% of the
material can be dispensed. In the U.S., unlike aerosols, the actual content
(m fluid ounces), rather than the dispensed weight, is the basis for the
declaration of contents on the label. However, labeling requirements will
vary with the country having jurisdiction.
173
-------
In one instance, an aqua-colored, rather viscous specialty shampoo was
found to change color rapidly, toward green, then olive green, and finally
yellow when packed in glass and exposed to sunlight. No color change has yet
been seen in this product when packed for eight months in the Boxal pump
dispenser,
INDEPENDENT BAG-IN-CAN SYSTEMS
During the late 1950s, inventor Ellis Reyner began to introduce aerosol
marketers and fillers to his patented process for a product designed to
permanently separate the propellant and product. In its simplest form, his
innovation consisted of a plastic pouch, to be inserted in an aerosol can,
either before or after filling with the concentrate. The pouch contained two
chemicals; sodium bicarbonate (NaHC03) powder and a 50% solution of citric
acid [C3H40(CQ2H)3] in separate burstable tubes. When the two chemicals come
together, during a deliberate rupturing process directly ahead of the valve
insertion and sealing operation, they chemically react to produce various
sodium citrate salts and carbon dioxide (C02) gas. The outer envelope of the
pouch remains intact, but it swells as a result of carbon dioxide pressure and
presses against the can and the contents, so that when the valve is actuated,
product flows out of the can as a coarse (non-aerated) spray, as a gel, paste,
post-foaming gel, stream, or foam.
A problem with the early developments was that the bag was subject to gas
permeation, stress cracking, product influences, and imperfect welding. These
problems were solved by using laminates, often including a core layer of
0,0005" (0.013 mm) aluminum foil to almost totally eliminate any permeation.
A less-effective barrier material is Mylar (polyethylene terephthalate -
biaxial), which also adds considerable strength to the bag,
A second problem was that the bag could initially swell up only to the
volume of the gas space over the concentrate. Because of various government
regulations limiting aerosol pressures to about 180 psig at 130° F (12.68 bars
at 54.5°C), the practical maximum pressure that the bag could exert at room
temperatures was 142 psig (10.0 bars), and many marketers were more comfort-
174
-------
able with 60 to 80% of this level. Following is an example of the pressure
decrease during use that would take place for a typical product:
Toothpaste.
250 mL of toothpaste, 1-0 mL for pouch, and 140 mL for head
space over the toothpaste.
140 psig at ambient temperature - initial, (9.86 bars)
Head space air compression to about 10% of original
volume, plus absorption of some of that into the tooth-
paste, is not considered here. (Can be reduced by vacuum
crimping.)
After the essentially complete discharge of toothpaste, the pouch volume
will increase from 10 mL to 400 mL.
After the initial step of gas formation in the bag, it swells to 140 mL
and has a pressure of 155 psi-absolute at ambient temperature.
Using Boyle's Law, the pressure drop during toothpaste expulsion will be:
Pf - Pj_ (Vj/Vj) - 155 (140/400) - 54.25 psi-absolute
P£ - 39.25 psig (2.76 bars)
Thus, the gauge pressure at ambient temperature is reduced from 140 to 39 psig
(9.86 to 2.76 bars).
Repeating this study using an initial gauge pressure of 100 psig, would
result in a final (can empty) pressure of only 25.25 psig (1.78 bars). This
degree of pressure drop will result in significant decreases in delivery rate,
especially for viscous products of positive yield point, during package life.
This drop can be reduced by using what has been termed a "functional slack
fill" of product, such as a 50-volume percent quantity, but this increases the
cost per unit weight or volume of product and has other disadvantages.
Product:
Volume Fill:
Pressure:
Note:
175
-------
Around 1975, the Grow Group, Inc. became interested in the Reyner system,
thinking it could be refined to deliver a certain amount of gas at the onset,
and that maintenance amounts could be provided as needed during use. After a
research period lasting two years, the Grow Group announced the acquisition of
Reyner's interests and the formation of Enviro-Spray Systems, Inc. to promote
and sell the improved pouches and filling technology that had been developed.
The pouch now contained one fairly large inner container of 50% citric
acid solution in water, plus six other much smaller containers. The larger
receptacle could be torn or ruptured, either by striking the inserted bag with
a small ram, or by the action of the vacuum crimping operation, releasing the
contents and generating from 60 to 100 psig (4.2 to 7.0 bars) of carbon
dioxide gas. As the product was used, the bag expanded as the head space
expanded, and at a pre-engineered point the first smaller compartment of
citric acid solution was breached. This returned the pressure to the original
level. The process was repeated until the last citric acid receptacle had
been ruptured.
With this sort of arrangement, the pressure could go (for example) from
100 psig to 80 psig, back to 100 psig, down to 77 psig, up to 103 psig, etc.
as many times as there were citric acid receptacles. The relative complexity
of having pressures of over 60 to 80 psig (4.2 to 5.6 bars) was questioned
during the development of this system, as was the need for six maintenance
system bags. Four of these appeared to be adequate, and future editions of
the pouch ultimately used only four.
Other refinements include adding a flow tube, which consisted of a
suitable length of aerosol valve dip-tubing so that the expanding pouch would
not press hard against the middle or upper potions of the can wall and cut off
or trap product below that point, keeping it from being discharged. Finally,
the reservoir of sodium bicarbonate was contained in a water-soluble polyvinyl
alcohol plastic, so that when the water-impermeable membrane between the
primary citric acid sack and sodium bicarbonate compartment was deliberately
ruptured by ram or vacuum action, the pouch would not instantly inflate, but
176
-------
would be delayed for one minute to allow time for the valve crimping (or
sealing) operation.
Since the bag would be expected to inflate after the package was sealed,
a way had to be found to authenticate that it had actually expanded. On
production lines this was done by means of X-ray based level measuring
equipment. Pressure measuring could be performed on a laboratory or statisti-
cal production quality assurance scale, and this also showed if only the main
citric acid receptacle had ruptured. One problem with the system, even in
units produced in 1989, is that two or more of the citric acid containers can
rupture if there is a problem with bag quality, resulting in excessive
internal pressures,
Figure 4 depicts a slow-speed aerosol line, using semi-automatic pouch-
stuffers, rated at about 18 units per minute for each of the two machines in
use. The rest of the line is fairly standard, except for the level checker,
-which is used to ensure pouch inflation.
The preferred valve is the Precision Valve Corporation Model 1-NN, with
a 2 X 0.5-mm stem slotted "Enviro-Spray" type housing. Any type of actuator
button or spout may be used. The standard pouch is designed to be used with a
202 X 514 (53-mm diameter X 300-mL) can with a 170-mL product fill.
The firm suggests the following product possibilities;
• Air Fresheners;
• Plant Sprays:
Leaf Shines,
Aphid control,
Fertilizer Concentrates;
• Petroleum Jelly (for example, for babies);
• Bathroom Cleaners;
• Toothpaste;
• Post-foaming Gels (as shave creams);
• Metered Dispensing (micro and macro);
• Toppings;
177
-------
SYPHON TUBE
INSERTER
CODER
VISCOUS
FILLER
CASE
PACKER
CASE
STORAGE
AUTOMATIC
QUALITY
'CONTROL
CHECKER
CONTAINER
IN-FEED
PRODUCT
LLER
WATER
BATH
AUTOMATIC
GrowPak
POUCH
INSERTING
MACHINE
VALVE
CRIMPER
WEIGHT
CHECKER
<
CD
O
If)
Q
Figure 4. Slow-Speed Grow Pak Packaging
178
-------
• Cheeses or Snack Items;
• Waterless Hand Cleaners and Related Lotions;
• Pet Care Items;
Groomers,
Shampoos - optionally insecticidal,
Flea & Tick Sprays (soundless);
• Cake Decorations;
• Industrial Maintenance Items, including lubricants;
• Selected Coatings;
• Furniture Polish (in lotion forms); and
• Mustard, Catsup, Purees and so forth.
Those products actually marketed in the Enviro-Spray System include the
following:
• Tomato and Vegetable Insecticide;
¦ House Plant Insecticide;
• Rose 6c Flower Insecticide;
• Flea & Tick Spray for Dogs;
• Flea & Tick Repellant Spray ,for Dogs;
• Spray for Cats - Insecticide;
• Leaf Shine for Ornamentals;
• "Le Gel" by Williams (Beecham) Shave Cream;
• "Kouros" by Yves Saint Laurent;
• "Algipan" by Labaz Sanofi- Rubifacient Cream;
• "CCRF" Tomato Paste, Tomato Ketchup, and Mustard;
• "Mist & Feed" Foilant Nutrient Spray; and
• Beecham Caovel Pet Insecticide Spray.
In 1986, costs were $3.59 to $8.99 for cans ranging from 7-Av,oz. (200-g)
to 32-Av.oz. (946-g) net weight. Containers were also sold for such special-
ties as institutional "gallon-size" insecticides, the pressurization of low-
gas beer kegs, soft drink dispensers designed to operate under "no gravity"
conditions in the NASA space program, etc. The pet sprays benefitted from the
soundless delivery of the Enviro-Spray dispensers, since pets can hear and are
179
-------
distressed by the very high-pitched sound of standard aerosol sprays, except
for those pressurized by air or nitrogen gases.
The second largest Enviro-Spray in Europe is a line of four food products
by C.C.R.F. (France), under the. brandname of Claude Vetillard. They include
Tomato Puree, Double Concentrated 28% Mustard "Forte de Dijon," and Tomato
Ketchup, packed to 280 g (250 mL) in metal box "Slimline" cans measuring 57 X
164 mm. Each is fitted with a Precision valve and "captured plug" spout.
After 27 months, some cans of the Tomato Ketchup have shown a slight seepage
of the product at the juncture or top arid side seams. With appropriate
adhesive-backed formula and precautionary stickers, these cans have made a
modest entry into the more expensive U.S. specialty shops, such as those at
airports and major hotels.
PUMP SPRAYS - ASPIRATOR TYPES
Pump-sprays have taken many forms. There are those whose pressure is
generated within the meter-spray valve, and others (much rarer) whose pressure
is produced in the container by various means. In the unique "Pre-Val" unit,
developed by the Precision Valve Corporation (1975), a glass or plastic jar is
filled with product and then sprayed out by aspirating it up a dip tube
leading into an upper "Pressure Pack" containing a liquid propellant. When
the valve button is depressed, propellant gas is discharged, sucking up a
certain amount of the concentrate "and discharging it as well. The usual ratio
is about 4 to 1, so that approximately 400 g of concentrate is dispensed by
100 g of a hydrocarbon blend. No solubility of propellant and concentrate is
necessary. If the concentrate might dry in the valve orifice to form a solid
clog, or after use, the jar portion can be disconnected and the valve actuated
to blow the mechanism essentially free of all product. The dispenser, along
with refill units, can be purchased in hardware stores, lumber yards, and
similar outlets.
The original form of the aspirator-type dispenser is the pump-sprayer for
space spray insecticides. This normally consists of a tubular barrel (the
180
-------
cylinder) and a thin piston at the end of a fairly long rod, as shown in
Figure 5.
Figure 5. The "Flit Gun" Aspirator-Type Insecticide Space Sprayer
The product is aspirated up a plastic or metal dip tube and through a jet
orifice that ends in the midst of a vigorous stream of air, at 10 to 20 psig
(0.70 to 1.41 bar), directed at it from a nozzle at the end of the cylinder.
The ratio of low-pressure air to amount of aspirated product is the primary
determinant of particle size distribution. Ideally, the particle size would
be less than 30/i. Otherwise, the larger particles would fall to the floor
rather quickly and be of little use in killing houseflies, mosquitoes, and
other flying insects. The largest - selling insect sprayers have been a line
called "Quick Henry, the FLIT," sold by Penola Oil & Chemical Corporation, and
later by Esso Oil Company, Humble Oil & Refining Co., and still more recently
by Exxon, Inc.
These sprayers were often manufactured in very expensive forms, such as
in nickel-plated bronze, with decorative designs and printing (sometimes
engraved), and with small 'boxes of replacement piston "leathers" and spare
glass jars that were often customized and suitably embossed with the name of
the sprayer. Quart (946 mL) cans of insecticides in low-odor kerosene
solvents were available from Penola, Esso, Sinclair, Phillips, Conoco, Shell,
Peneco, Gulf, Pennsoil, Rex, Sohio, Cook, and other oil companies, which would
work well in any of the available sprayers.
181
-------
Today, a few firms make all-plastic sprayers, except for the metal
orifice areas, but they are not advertised, and sales volume is limited. "F"-
style or cone-top cans of insecticidal concentrates can also be found, but
availability is also -limited. These sprayers are far more popular in coun-
tries other than the U.S., Europe, and Japan.
The aspirator-type sprayers are the only sprayers, other than aerosols,
that can produce a space spray. They have been so closely associated,
however, with (smelly) insecticides that it would not be possible to market
them for air fresheners or for other uses in the U.S. However, some "mini"-
sprayers of this type are occasionally available for household perfumes in
•Latin America, and the rubber-bulb type aspirator may still be seen for
personal fragrancing applications, generally in rather fancy designs.
Colognes are available in bottles exceeding one U.S. gallon (3,786 mL)
capacity for refilling other containers and dispensers, so a supply of the
product itself is not a problem.
PUMP-SPRAYS - STANDARD TYPES
The Fineer-Pump Soraver
The most common pump sprayer is commonly called the finger-pump, mainly
to distinguish it from the trigger-action sprayer. The finger pump is
available from the same manufacturers that produce aerosol valves, such as the
Calmar Corporation, Bakan Products Co., Risdon Manufacturing Co, (Division of
CMP Products, Ltd., as of 1989), Emson Research Company, and others. The
largest is probably the Seaquist Closures Division of Pittway, Inc., located
in Gary, IL (U.S.). In many cases, it takes an expert to distinguish between
a ferrule-type aerosol valve and a ferrule-type finger-pump valve; they are
often made by the same company and have two or three components in common.
Distinguishing features of the finger-action valve are its larger, more
complex valve structure and its often clear plastic body component that
displays a complicated spring above a metallic ball check unit. The best
indicator is the type of container. If it is a plain glass bottle larger than
one fluid ounce (29,57 mL), or a small glass bottle with flat surfaces or
182
-------
sharp corners, or a polyethylene or polypropylene or vinyl bottle, or if the
bottle can be deformed by squeezing, or if the valve is attached by means of a
screw-threaded connection, the valve is not an aerosol valve. Some finger-
action valves are placed in one-inch aerosol cups and crimped onto aerosol
cans. These defy identification except by operating them.
The usual aerosol valve has up to seven components' and sells for about
$40.00 per thousand. In contrast, the finger-action valve has eleven com-
ponents, some of which must fit together with tolerances more demanding than
those of aerosol counterparts. Consequently, these valves sell for two to
three times the cost of the aerosol types, depending on size and other
factors.
An illustrative sketch of a typical screw-cap mounted finger-action valve
is shown in Figure 6.
The finger-action valve delivers a fixed amount of product per actuation,
from 125 to 200 microliters. To convert this to milligrams per shot, simply
multiply the microliter rating by the product density. Densities may vary by
20% or more. Ethanol solutions, such as hair sprays, have the lowest density,
at about 0.80 g/mL.
As the actuator is depressed, the adapter and stem components are forced
downward as well. The stem travels a fixed distance into the body chamber,
which is normally filled with product in the primed valve, The product forces
the piston to expand outward, allowing product to flow past it and into the
cross-hole orifices of the stem. From there it travels up the stem hole,
through the adapter and button, and out as a stream, or spray. When the
button is released, the spring forces the stem upward, creating a partial
vacuum in the chamber and causing the ball to lift and allow product to flow
upward to refill the body chamber with the product.
183
-------
1.03 MAX.
(26.162)
J*W\
Ms
*•$<$. i
twin yft
DIP TUBE LENGTH
CUT TO SUIT
HOOD
Polypropylene
INSERT
Acetal
BUTTON
Polypropylene
ADAPTOR
Acstai
STEM
Acatal
PISTON
Polyethylene
GASKET '
Polyethylene
CLOSURE-22-415
Polypropylene
SPRING
.023 Wire
BODY
Polyorooyline
BALL
1/8" Nickel Plated or S.S.
DIP TUBE
Polyethylene
/
I BUTTON
¦ ADAPTOR
I STEM
~ PISTON
H GASKET
¦ INSERT
O CLOSURE
13 SPRING
¦ BODY
~ BALL
¦ DIP TUBE
Figure 6. Cross-Section of Finger-Action Seaquist Valve,
Set in 22-415 Closure
184
-------
The complexity of the finger-pump valve systems makes them sensitive to
strong solvents, solid suspension products and thixotropic viscous products.
As a rule, they are only used for water-based, hydroalcoholic, and alcoholic
formulations. The complexity of finger-pump valves is compared with the
relative simplicity of a non-metering aerosol valve m the drawings presented
in Figure 7. The complexity of the metering aerosol valve is more or less
equivalent to that of the pump-action types.
Along with the complexity of these valves comes a considerable increase
in cost, compared with aerosol valve options. Costs may be controlled by
using the largest practical containers (to lower cost per unit of product), by
marketing refill containers that use simple screw-caps, and by emphasizing the
use of finger-pump valves with colognes, sachets, perfumes, pharmaceutical,
and other generally high-cost products. In the case of perfumes and some
medicinal items, the metering action of the finger-pumps is a distinct
advantage in conserving and regulating the use of these products,
The pressure build-up within the chamber of the finger-pump valve is a
complex function of the pressure applied to the actuator, the size of the exit
orifices (diameter mostly, but also length), product viscosity, and other
factors, but it is generally in the order of 50 psig (3.5 bars). Mechanical
breakup spray heads do a fairly good job of developing spray patterns when the
liquid is at a pressure of about 18 psig (1.27 bar) or higher. At excessive
pressures (rarely attainable) there is some denigration of the pattern, such
as "hot spotting."
The spray pattern and particle size distribution of finger-pump sprays is
due to the purely mechanical breakup attributes of the specially designed two-
piece button. Two to four tangential channels converge the product into a
central swirl chamber, where it must turn at right angles to pass through the
terminal orifice.
185
-------
I TNT' Pump
"The Nan-Throttling"
tzv'm
¦fllxiJtl
SL-i4XD MICRO-MIST
PUMP
MATERIALSAND COMPONENTS IN VARIOUS VALVES
A PISTON - Polyethylene
B COLLAR - Polyethylene
C MOUNTING GOT - Alum.
D GASKET - Rubber
E VALVE - Acetal
p INNER PISTON - P.E.
G SPRING - SS-302
H BODY INSERT - P.E.
I BODY - Polypropylene
J BALL - Stainlesa Steel
K DIP TUBE - Polyprop.
A ACTUATOR - Linear Polyethylene
B ACTUATOR INSERT - Acetal
C ACTUATOR ADAPTER - Polypropylene •
D BALL - Stainless Steel #302 or #305
E COLLAR - Linear Polyethylene
F BALL-SEAL INSERT - Acetal
G SPRING - SS-302
H BODY & BODY INSERT - Polypropylene
I DIP TUBS - Polypropylene
J PISTON - Linear Polyethylene
K CLOSURE - Aluminum - anodized
L GASKET - Rubber of Polyethylene
A STEM - Nylon or Acetal
B STEM GASKET - luna-N
MOUNTING CUP - Aluminum
BODY GASKET - Buna-N
BODY - Nylon or Acetal
SPRING - SS-302
DIP TUBE - Capillary PP
with-0.020", 0,030" or
0.040" I.D., or 0.125"
1.D. Polyethylene
Figure 7. Comparison of Risdon (Dispensing Systems Division) Finger-Pump
20nun TNT Pump and SL-40 Micro-Mist vs. 20rani Aerosol Valve
186
-------
Unlike most aerosols, where exploding actions caused by the instantaneous
depressurization of liquified propellant act to reduce particle size to
various degrees, the particle size of finger-pump sprays is regarded as very
coarse, and best suited for surface applications. As a rule, spray particles
from finger-pump units will strike the floor within five seconds or less,
regardless of the initial direction of the spray. The only aerosols whose
sprays compare with those of finger-pumps are "nitrosols," those pressurized
with 1 to 6 grams of nitrogen gas (depending on size), and water-based types
designed to have the hydrocarbon propellant separate on top as a discrete
layer. Most of these latter products, such as starches and fabric finishes,
carry a top-of-can message of "Shake Before Using" to obtain a better spray
pattern by incorporating'some propellant into the exiting product.
The finger-pump particle size distribution is compared with those of
several similar products in Table 46.
Spray patterns of the finger-pumps vary from quite wide to very narrow.
The valve of the "Moi'Stir" Mouth Moistener (Kingswood Laboratories, Inc.)
will cast heavy droplets in a 7" (180-mm) slightly oval pattern onto a target
panel 60" (1.51 m) distant. A "Hot Shot" Wasp & Hornet Spray (finger-action
Calmar valve, ex. Bakan) by United Industries Corporation (St. Louis, MO),
formerly Chemsico, Inc., will cast a narrow spray over 12 feet (4.35 m).
Cologne sprays are usually the widest, with the particles traveling fairly
slowly outward. In fact, cologne sprays, if deliberately ignited, will
quickly burn back to the valve button and burn the fingertip of the operator,
unless the spray shuts off first.
One of the detractions of the finger-action spray is the number of times
the'actuator must be depressed to empty the dispenser. For example, consider
an S.O-fluid ounce (299 mL) container, which is dispensed at the rate of 0.125
mL (125jiL, or 100 nig) per shot, The required number of actuations to empty
the dispenser will be 2,396. This number can be approximately halved by using
finger-pump valves with 0.205 mL and similar size-metering dimensions. Many
pump-spray marketers compensate for the slow use-up rate, compared with the
I
187
-------
TABLE 46. AEROSOL AND FINGER-PUMP HAIR SPRAYS; COMPARISON OF
PARTICLE SIZE DISTRIBUTIONS
Particle Size Ranee (u)*
% of
Below
Over
Type & Valve
Propellants
10#*
10? - 201*
20- 50^i
50/i
Finger-]
Pump
0
0
2
14
8 6
mechanical
breakup
(MB)
Aerosol
Non-MJB
20
1
5
38
66
Aerosol
MB
20
3
8
48
41
Aerosol
Non-MB
25
2
8
49
41
Aerosol
MB
25
5
15.
60
20
Aerosol
MBb
16.67
0.5
2
22.5
75
Aerosol
MBb
32
16
18
39
27
Aerosol
MBb
38
11
32
56
1
Aerosol
Non-MBb"c
74
24
76
0
0
"Measurements made with a Malvern ST 1800 analyzer, at 90° to spray axis and
16" (406 mm) from the actuator. Run in duplicate,
bThese are produced outside the U.S.
cThe large amount of (CFC-11/12) propellant used in this product reflects the
high cost of ethanol in the country where it is produced; the "alcohol tax"
cannot be avoided, as in the U.S., for approved uses.
188
-------
aerosol, by increasing the level of film-forming resin in the hair product
formulation.
Some characteristics of pump-sprays are more economically attractive than
aerosols. For example, a plain glass cologne bottle, is less costly than a
heavier-walled, pressure-tested and PVC "Lamisol"-coated glass - in-plastic
aerosol bottle. The plain bottle also has a number of other advantages
relating to design flexibility. The filling operation for pumps is a single
stage operation; the aerosols, however, must be filled and then gassed,
requiring at least two stages. They must also be hot-tanked.
Aerosol containers larger than 4 fluid ounces (118.3 mL) are restricted
to cylinders of aluminum or steel, at least in the U.S.; whereas, finger-pump
dispensers may be made of various plastic or glass containers and be attrac-
tively shaped. Unlike aerosols, they are not limited to 819.4 mL in size,
although very few are more than about 12 fluid ounces (355 mL), for practical
reasons.
The flammability of aerosols and finger-pumps is commensurate in several
ways. Formulas for both systems may range from 0% to 100% of flammable
components. They pose approximately equal levels of hazard if exposed to an
ongoing fire in a warehouse. The finger-pump can produce a flame volume of
from 0.8 to 1.6 U.S. Gallons (3,000 to 6,000 mL) per actuation if the contents
are hair spray or bug killer, which contain essentially 100% flammable'
ingredients. The aerosol is similar, but the flame volume may be two or three
times larger and may be sustained by merely keeping the button depressed.
Aerosols can rupture if overheated, and if a flame source is present, they may
generate a fireball up to 9 feet (2.7 m) in diameter.
Typical products that have been successfully marketed in finger-pump
sprayers include following;
Bug Killers (such as ant, roach, spider, and bee killers)
Weed Killers
Pet Sprays (often for insecticidal or grooming purposes)
189
-------
Colognes and Perfumes
Hair Sprays
Hair Moisturizers
Curl Activators
Lens Cleaners (such as anti-fog and anti-static types)
Vermouth (for dry martinis)
Germicides (including those for pre-operation washing)
Spot Cleaners
Pre-suntanning Accelerator
Facial Rinse
Cookware Lubricant
Contact Lens Rinsing Sprays (requires Thimerisol or other disinfectant)
Window Cleaners
Topical Sprays (such as benzocaine or rubifacient types)
Silver Polish Sprays
Throat Sprays
Leaf Shine Sprays
Chrome Polishing Sprays (automotive uses)
Stainless Steel Cleaners
Mildewcides
One disadvantage of finger-sprays not yet discussed is that all models to
varying degrees produce extremely coarse dribbles at the very beginning and
the very end of each actuation. These heavy droplets fall downward very fast
spotting polished,wood furniture, window sills, flat glass surfaces and some
textiles, also cooling or wetting the skin away from the sprayed area of the
body.
Finger-pump sprays are usually not used with a number of product types
such as the following:
Volatile flammables (such as cigarette lighter fluids)
Viscous liquids (spray extra coarse, or may not spray)
190
-------
Strong solvents
(such as nail polish removers & insect repel
lents)
Sterile liquids
(sterility is lost at the first actuation)
Acidic liquids
(acetal valve components dissolve below pH
3.6)
Moisture-sensitive
liquids
(moisture enters by return air and permeation)
Suspensoid fluids
(valve plugging can readily occur)
Foam-type emulsions (foaming will not occur to any extent)
Polyethylene warping
liquids
(such as oleic acid or some block polymers)
Staining liquids
(such as food colors, dyes, etc. because of
dribble)
Sensitive liquids
(such as those harmed by air or light)
Two-phased liquids
(phases will reform in valve chamber and be
resistant to reconstitutLon by shalcxng)
High-odor liquids
(In plastic bottles)
(garlic concentrates, etc. will permeate)
In spite of all these apparent limitations, the finger-pump sprays enjoy a
business volume exceeding one billion units a year and remain the major
competitor to aerosols.
191
-------
Trigger-Pump Sprayers
The sprayer is one form of the trigger-pump; the others extrude pastes,
gels, or liquid products. Trigger-pump sprayers are more costly than finger-
pump sprayers; they are used with somewhat larger dispensers, and more
emphasis is given to refill units. The trigger mechanism facilitates the
dispensing of larger quantities of product per shot, and the mechanical
advantage or leverage feature of the pinioned trigger itself provides higher
internal pressure in the chamber. They are generally viewed as more utili-
tarian than discretionary; for example, there are few if any trigger type
pump-action hair sprays. (However, trigger pump lotions and cosmetic pastes
are aesthetic and quite popular.)
Most trigger sprays are used for cleaning purposes, such as pre-laundry
spot cleaners, disinfectant cleaners for hard surfaces, carpet cleaners,
window cleaners, automotive cleaner and wax, vinyl top cleaners, industrial
lubricant cleaners, and concrete floor (grease and oil) cleaners. Container
sizes of up to one U.S. Gallon (3,784 mL) are available for institutional
uses.
The operational principles, compatibility characteristics, and most other
properties of the trigger-pump sprayers are equivalent to those of the smaller
finger-pump sprayers and need not be repeated here.
Finger-Pump Extruders
A minor modification of the actuator changes the finger-pump sprayer into
an extruder suitable for dispensing lotions, creams ointments, gels, pastes,
viscous liquids, and measured amounts of various concentrates for dilution
with fixed amounts of water, The actuator is removed and replaced with a
spout with a very narrow tubular exit pipe. The small amount discharged per
shot makes it useful for costly pharmaceutical, skin dewrinklers, perfumed
lotions and similar products. In Europe, a vitamin mixture and an ear-wax
softener are sold in this form. A concentrated cypermethrin and K-methrin
mixture that is dripped onto an absorbent wafer measuring about 17 X 45 X 2 mm
192
-------
xxx siZ6 is fllso sold in thxs form. Th& treated wsfcr xs slxpped xxito a small
holder that plugs into a wall socket which gently heats it to vaporize the
insecticidal additives. The active ingredients are not volatilized in
sufficient concentrations to be lethal, but they are so irritating to mos-
quxtoes that they vacate the room xf possible. The repellent actxon lasts S
to 10 hours, ensuring people a good night's sleep. Most of the sales are in
Mediterranean countries, where the product has made serious inroads into the
much more costly aerosol insecticide business.
Trigger-Pump Extruders
Various modifications can be made to the trigger-pump sprayer to change
it to a device with a spout able to dispense lotions, gels, and similar
products in the form of a stream or ribbon. Simplified and lower-cost
versions are also in demand that are used to discharge relatively large, fixed
volumes of dishwashing detergents, fabric softeners, and other cleaners. They
will have almost no effect on the aerosol market as possible alternatives and
are not discussed further.
DISPENSING CLOSURES
One of the simplest possible designs is the screw-threaded closure or cap
with a dispensing hole able to be plugged shut by various means. Three of
these designs are illustrated in Figure 8.
To operate these, the dispenser is held inverted to get the product near
the orifice, after which, the "F"-style metal can (oblong, with large front
and back flat surfaces) or flexible plastic container is squeezed, expelling a
stream or ribbon of the product. Dispensers come in sizes of 6 to 64 fluid
ounces (177 to 1,892 mL) and can conveniently dispense liquids, thin gels,
soft creams, and lotions, as long as they are flowable. These containers are
used for charcoal lighters, various cosmetics, toiletries, personal care
products, paint solvents, paint strippers and furniture polishes.
193
-------
SPUD ¦KM
Mf T TAB
QIC* QHIPICl
OECK
urn* himoii
covin NIMOi
COVEN
COVM SKIRT
SNAP TOP
STRAP ELBOM
STRAP
LOWiA MIMQI
SKIRT
ACTUATOR
FINGER SECTION 0QOY TUBE
DECK
DISC
TOP
ORIFICE
SOOY
BODY TUB6
ACTUATOR
ORIFICE
5gy OECK
- ^
BODY
TOGGLE
CAP
Figure 8. Various Dispensing Closures-Made by the Seaquisc Closures Division
194
-------
In addition to the designs illustrated above, there are turret spouts
(truncated cone profile), lever spouts--in which a small pinioned plastic
section is rotated 90° upward to operate the closure--and several related
forms. They are increasingly used instead of the simple, detachable screw-cap
dispensers. Uses include certain foods (such as oleomargarine pourables,
ketchup, and mustard), lubricants, silicone shoe and boot dressing, some
medicinals, and solvents for home use, artists, and industry.
These products are major competitors with aerosols in the lubricant field
(aerosol volume 95,000,000 units in 1988), for carburetor and choke cleaners
(aerosols 57,000,000), waxes and polishes (aerosols 129,000,000), and certain
other overlap product areas. Since the closure is a single polyethylene
molded unit, generally applied semi-automatically as a replacement for screw-
threads, it is a very economical option. Some models can be made child
resistant.
PRESSURIZING DISPENSERS
Twist-N-Mist II
Over the years, several firms have developed various pressurized packag-
ing systems quite different from the conventional aerosol form. They invar-
iably use air pressure, the restorative pressure from an expanded rubber
bladder, or some sim i. 1 a r arrangement as the dispensing method. They are
characterized by delivering either very coarse sprays or various lotions and
semi-solid products, usually one or the other.
The Twist-N-Mist II is a development of the CIDCO Group, Inc. of Denver,
CO, which holds several U.S. Patents that cover the principles of the device,
as well as those employed in related dispensers; Pull-N-Mist and Dial-A-
Spray, details of which are still experimental and have not yet been released.
The firm also holds several foreign patents.
As in all such products, energy must be imparted to the dispenser to take
the place of the propellant gases used in aerosol forms. For Twist-N-Mist II,
195
-------
that energy is supplied manually, by rotating the full-diameter screw-cap and
integral piston.
The current model of Twist-N-Mist II, of which several hundred have been
made, uses a three-component outer shell assembly, which measures about 2 3/4"
X 6 1/2" (70 X 165 mm) and consists of an HDPE threaded base, threaded top,
and matching body, as shown in Figure 9.
By turning (twisting) the threaded cap several revolutions the integral
piston in the base of the cap is raised about 1/2 inch (12.7 mm)' or so,
creating a vacuum in the cylinder (reservoir) below. This causes the product
to rise up the dip tube, past the stainless steel ball check valve, to fill
the cavity. Enough is drawn up to provide a 7- to 20-second spray time,
depending on the valve orifice.
The cap is now twisted an equal number of turns 'in the opposite direc-
tion, forcing the integral piston downward until it hits against the base of
the reservoir. This action causes pressure to develop in the reservoir and
forces the trapped product downward into a Buna-N rubber bladder, which
expands accordingly. The- memory of the elastomer causes pressure, which
decreases to some extent as the product is dispensed through an aerosol type
valve, allowing the bladder to slowly regain its original "test-tube-like"
profile. The process must be repeated for another actuation. The dimensional
changes in the unit during the suction and pressurization stages are shown in
Figure 10,
As a fail-safe feature, the contents of the pressurized rubber bladder
will very slowly bleed back past the' check valve barrier and into the main
product storage compartment. The bleed-back time can be controlled by varying
the surface finish of the check ball or check ball receptacle, or, if the
product is viscous, by grooving the ball.
A number of other features are possible. The amount of pressurized
product (and thus spray time) can be pre-engineering by proper sizing of the
reservoir, bladder and/or nozzle orifice. The main section of the dispenser,
196
-------
(HDPE)
TiMop
{MDPEI
CUekbal
(ssainlBi
Dipt
(HDPE)
omrm
Figure 9, Twist-N-Mist II
197
-------
FILLING RESERVOIR Turning cap to
the up position opens the reservoir
acid fills it through auction on the
dip tube.
DISPENSING SEQUENCE Twisting cap
back to che down position forces the
produce from reservoir to bladder.
Pressing actuator discharges contents.
gure 10. Suction and Pressurization Stages of the Twist-N-Mist II Dispenser
198
-------
made from injecting blow-molded HDPE or HDPP, can be contoured to a modest
degree inward, outward, or both, if the screw-threaded top and bottom sections
remain round. Technically, the dispenser can be provided with an integral
bottom at a slight decrease in cost, but this would make it into a one-time
service unit, instead of a reusable type and increase cost-per-ounce (cost per
mL) significantly. This option is not generally recommended.
Because the upper cavities are completely filled with product, the unit
may be used with the dispenser held in any direction. It delivers about 95+%
of the contents. Corrosion is not a problem, since the only metal parts are a
stainless steel spring and ball. Stress cracking has been noted as a problem
with early single cavity models, mainly affecting the screw-threaded dome
section and allowing leakage of the product. If refined models are resistant
to stress cracking, they should be tested with surfactant (as non-ionic) water
solutions that can often induce this problem in polyethylenes that are not
formulated properly.
The CIDCO Group, Inc. recites the shortcomings of aerosols (their major
target) as well as of finger-pumps and trigger-pumps, claiming that their
dispenser, while somewhat costly to buy the first time, has long-range
advantages, especially if refilled.
However, several turns may be necessary to pull product from the main
chamber and then force it into the Buna-N Rubber bladder against the back
pressure from that diaphragm. The spray duration could cease in the middle of
a spray episode, requiring the user to delay completion for an estimated 15 to
30 seconds to recharge the can. The spray is much coarser than that of
aerosol sprays, except for nitrosols. No foams can be produced. No solvents
that have a profound swelling or deleterious effect upon the Buna-N bladder
can be used, except perhaps at low concentrations. Product darkness or odors
%
may develop unless the rubber bladder is specially lined, as in the Exxel
system discussed below.
199
-------
The Exxel System
Briefly, this is another dispenser option where the product is contained
in a thick, squeezable rubber sleeve open at one end, but in this case all the
product is compressed into the inner container by a manufacturer or packager.
The dispenser has aerosol properties, in that the product is always under
.pressure. However, there are differences. Sprays are propellant-free, and
therefore very coarse or wet, and no foam type products can be provided except
for post¦foaming gel types.
The following steps are required to manufacture the Exxel System dis-
penser:
• Stretch-blow a biaxially oriented, thin-walled polyethylene tera-
phthalate (PET) bottle;
• Form longitudinal pleats in the bottle, using patented equipment;
• Apply a double layer of barrier sealant and liquid latex to the
bottle;
• Insert a customized valve and clinch in place at the top ring of the
bottle;
• Insert bottle into a rubber sleeve;
• Place container into a suitable outer container and attach at the
top; and
• Force a predetermined amount of product into inner container via the
valve.
200
-------
Construction materials that can contact products are limited to the PET
bottle, the Nylon 66 valve housing, natural polypropylene, the HDPE button,
and either the SS #302 or #316 spring. An insignificant exposure to the
PET/valve gasket must be mentioned. The gasket is available in various
materials.
A sampling of products currently being packed in the Exxel system appears
in Table 47.
Exxel comments that skin care, hair care, and pharmaceutical products of
the post-forming gel type are well along in the development stages. Also,
several medicinal ointments are under intensive study by Upjohn and others.
Cost comparisons can be made with other forms of packaging, using the tabu-
lated data in Table 48.
The Exxel system is incompatible, to varying degrees, with certain
formulations, Following is a list of ingredients and characteristics that
would make a product incompatible with the Exxel system:
• Certain polymer solvents--terpenes,• ketones, etc.;
• pH Values over 10.0;
• Isopropanol, above 5.0%;
• Prolonged exposures to over 113*F (45®C);
• Particulate matter--since effective shake-be fore -use is impossible;
• High surface tension breakup products;
• Resins with an ability to dry and clog actuators;
201
-------
TABLE 47. TYPICAL CURRENT CUSTOMERS AND PRODUCTS OF THE EXXEL SYSTEM
Company
Product
Air Products and Chemicals Company
Chanel, Inc.
Kobayashi Pharmaceuticals Company
Nihon Sanso, Ltd.
Prudue Frederich, Inc.
P.R. Hertensen
Tokyo Aerosol Co.
Wella
Jergens
Westwood Pharmaceuticals, Inc.
Adrien Arpel
Estee Lauder, Ltd.
HiLo Products
Laboratoires Goemar, S.A. (France)
Welding Flux Spray
Sun Oil Spary
Muscle Relaxant
Pure Food Products - sterile
"Betadyne" Solution®
"Citruscent" Fragrance
Hair Gel
Shampoo and Conditioner
Topical Lotionsb
"Alpha Keri" Spray Oil
"Aromafleur" Flower Extract Foam
Firming Masque
Hair Reviving Mist
"Silent Force" Flea Spray
"Tonialg" Restorative Conditioner
"Tonialg" Toning Lotion
"Tonialg" Night Creme
"Tonialg" Restorative Shampoo
"Tonialg" Hand & Body Creme
"Tonialg" Bath & Shower Gel
"Tonialg" Foaming Bath
"Tonialg" Cleanser
"Tonialg" Nourishing Creme
"Tonialg" Body Contouring Creme
aTamed Iodine formulation.
bAs of 1988.
202
-------
TABLE 48. COST OF EXXEL SYSTEM PACKAGING AND FILLING SERVICES
(VOLUME - 1MM)
Item 4 oz. ($/M) 7 oz. ($/M)
Snap Ring 16 16
Power Assembly Unit 241 274
Actuator 30 30
Overcap 22 22
Decorated Bottle 85 95
Filling Charge (Contract) 140 140
534 577
NOTE; Add $10M for 500,000 quantities and $20M for 250,000 quantities.
Add $25/M for pre-fill electron beam- sterilization.
203
-------
• Formulas that require in-package mixing, e.g., bi-phasics; and
• Ethanol, above 60%--should be carefully tested for compatibility.
The outer container may be made from glass, plastic metal, composites,
paper, or (theoretically) nothing at all. For automated filling, the con-
tainer should be able to support a hold-down filling force of 25 pounds (11.4
kg) without buckling. To accommodate the two Exxel System inner containers,
the minimum internal dimensions of the outer containers must be considered, as
shown in Table 49,
The smaller (4-fl.oz.) Exxel package will deliver 92 to 95% of its
contents before fully depressurizing. The 7-fl.oz. size will deliver 92 to
84.7%. These ranges are reduced to 90 to 93X in the case of fairly viscous
items with positive yield points. After about 86 to 88% of spray products
have been dispensed, the bag pressure falls below about 17.5 psig (1.23 bar)
and the spray pattern deteriorates rapidly. The pressure at which this occurs
depends on the ingredients and the viscosity of the formulation. As a rule,
storage weight loss will be 1.0% per year at ambient temperature or per month
at 104°F (40°C).
The Exxel System is self-pressurized and may be classed as an aerosol
under the DOT shipping regulations; however, DOT Exemption No. E-9607 has been
obtained by the Darworth Company (Div. of Ensign-Bickford, Inc.) to set aside
these requirements for hot tanking, etc. This now applies to all Exxel System
products.
The Mistlon System
The Mistlon Eco-Logical Spray Bottle is a dispenser developed in Japan,
made in South Korea, and offered for sale by the MONDEX Trade & Development
Corporation, 2 St. Clair Avenue - West (Suite 801), Toronto M4V 1L5, Canada.
It is cylindrical and measures 2 1/8" X 8 1/2" high (54 X 216 mm). The
wholesale price is about $1.00.
204
-------
TABLE 49. MINIMUM DIMENSIONS OF OUTER CONTAINERS FOR EXXEL UNITS
Dimension 4 oz, Size 7 oz. Size
Minimum length. Top of neck 5.450 in. 7.300 in.
finish to inside of bottom. (138 mm) (185 mm)
Minimum width'. Internal " 2.223 in. 2.223 in.
dimension. (56.5 mm) (56.5 mm)
Note: Intentionally underfilled Exxel units will permit the use of outer
containers with reduced minimum internal widths.
Outer containers require a vent hole of at least 0.015" (0.38 mm),
preferably in the base, but alternatively in the shoulder,
205
-------
To use the empty unit, the full-diameter polypropylene cap is removed,
after which a screw-threaded closure carrying an ordinary aerosol valve and
actuator is al-so removed. A quantity of product is poured into the bottle
through the one-inch (25.4 nun) opening. A typical fill is 250 mL. After
this, the closure is screwed back into place, allowing a thin rubber "0"-ring
to make a reliable heriueti.c seal. The base section [full-diameter and 1" high
(25.4 mm)] is now withdrawn, away from the rest of the unit, exposing a hollow
cylinder 11/16" in diameter by 3 11/16" long (17.5 X 93.7 mm), fitted with a
one-way compound valve. The hollow cylinder functions as a piston, within a
cylinder protruding up4ward into the container, also ending in a one-way valve.
To pressurize the air in the container, the base section is pumped a number of
times. By pressing a soft diaphragm in the center of the base, excess air
pressure within the hollow cylinder is removed, allowing it to fit snugly
against the bottom-most area of the body as before.
The unit is equipped with either a 0,010" (0.25 mm) or 0.014" (0.36 ram)
mechanical breakup bottom. In the case of water, these actuators will provide
an acceptable spray if the air pressure is 18 psig (1.17 bar) or greater. The
operating characteristics follow simple gas laws. This can be illustrated by
the following example.
Characteristics:
The head space volume is 100 mL.
The liquid volume is immaterial.
The applied pressure is 50 psig (3.52 bar).
Question:
How much product can be dispensed before the pressure- sinks to 18
psig (1.17 bar) and the spray starts to deteriorate?
206
-------
Solution:
Convert to absolute pressures.
50 psig - 64,7 psi-abs (4.56 bars - absolute)
18 psig - 32.7 psi-abs (2.30 bars - absolute)
Boyle's Law:
V2 = V (P /P2) = 100 mL X (64.7/32.7)
V2 - 197.9 mL
Change in head space volume.
% - V2 - V - 197.9 - 100.0 - 97.9 mL.
Answer:
97.9 mL of liquid can be dispensed before the spray deteriorates.
It follows that, the larger the head space, the more strokes of the
piston will be needed to pressurize to a given, level, and the more liquid can
be dispensed as a result.
With some degree of manual difficulty, the Mistlon unit can be pres-
surized to 65 psig (4.58 bars). There was no evidence of deformation at this
pressure. The unit might be pressurizable to well over 100 psig (7.04 bars)
without any problems unless it is strongly heated to the point where the
polypropylene begins to soften and become deformable.
The delivery rate will, of course, vary with the container pressure.
With the 0.014" (0.36-mm) MB valve button, water delivers at about 0.5 g/s at .
20 psig (1.41 bar) and about 0.72 g/s at 40 psig (2.82 bar).
Like the Twist-N-Mist dispenser, the unit is limited in terms of spray
particle size and range of products that can be dispetised. Highly flammable
207
-------
materials, those that deform polypropylene or attack polyvinylacetate, and
viscous fluids are among those that should not be used. The unit cannot be
used to generate a direct foam, but with a suitable straight bore actuator it
could direct a thin stream into the palm that would then spring into a foam,
Airspray
This product, which is similar to the Mistlon dispenser also uses a
pumping action to compress air into the pressure-resistant container. When
reasonably full, it must be pumped 10 to 20 times to create an effective" spray
that does not quickly deteriorate as pressure drops. As the container
empties, the numb.er of pumping strokes must be increased, but the pressure
lasts longer during dispensing. The unit must be held upright to keep the
diptub'e below the liquid surface, but if the container is held so that the
compressed air is unloaded, it can be quickly pumped up again, unlike aerosol
products with nitrogen or other propellants in low concentrations.
The cylinder is cylindrical to withstand the generated air pressures
without buckling or other deformations. Comments made about the Mistlon
dispenser apply here as well.
Invented in Sweden, the Airspray system was developed and refined by a
Dutch company, which marketed the unit in Europe for several years. In 1987
, they entered into an agreement with the National Can Corporation, which is now
a part of the American National Can Company unit of Pechiney, S.A., to
manufacture and market the system in the U.S. under license. As of 1989, the
system will be jointly marketed in the U.S. by Airspray International, Inc.
(Poir.pano Beach, FL) and American National Can Company (Chicago, IL) , It is
promoted in Canada by W. Braun & Company (Markham, Ontario L3R 3B3, Canada).
The system is offered in two versions: with a refillabie screw top and a
disposable crimp-on. It can be made in containers of plastic, metal, or
glass. PET containers are being developed at this time. All the parts are
plastic. Once pressurized to 55 psig (3.87 bars)--the recommended maximum--ic
will dispense up to 100 mL before repumping is needed. Airspray supplies an
208
-------
O.T.I, crimping machine for closing and pressurizing Che system at 1500 M/hr
with compressed air.
The Werding Nature Spray-Systems
A variety of inter-related systems have been developed by Werdi Spray,
S.A. 5, Route des Jeunes, CH-1227 Geneva (Switzerland). They are represented
in the U.S. by Werding Aerosol Technology Inc., U.S., located at 4978 Kings-
way, Burnaby, British Columbia V5H 2E4, Canada.
The firm makes both non-aerosol containers and their unique Werdi 'R'
Actuator. The latter can be designed to provide a constant delivery rate,
regardless of the internal pressure of the dispenser, and is thus most useful
for products pressurized with air, nitrogen, carbon dioxide, etc., where
pressure drops during use can exceed 70%. The Werdi (R' System comprises the
Werdi 'R' Actuator (fitted with the Werdi 'N' Nozzle and thrust regulator) and
the Werdi Valve. For lotions and creams, the Werdi 'RD' system is suggested,
which consists of the Werdi 'RD' Actuator (fitted with the thrust regulator
and a self-closing diffusor) and the Werdi Valve.
The Werdi 'M' Nozzle achieves a high mechanical breakup effect by means
of its multi-staged, interconnected Venturi system, and thus contributes more
to spray breakup than conventional (less costly) mechanical breakup actuators.
Fitted behind the nozzle in the actuator, the thrust regulator controls the
flow of product to the nozzle. The patented design includes two stainless
steel accelerator discs and a plastic expansion chamber as well as a special
regulation disc, which is cut, curved, and formed to exacting standards.
The regulation disc is compressed by higher pressures, but because of the
spring effect of the metal, this opens the cut and increases the orifice size
as the pressure drops. Turbulence intentionally created by the design of the
companion discs, as well as the nozzle itself, produces a resistance to the
product flow into the thrust regulator, whose force is directly proportional
to the pressure. The higher the pressure, the more these turbulent effects
209
-------
brake the delivery rate. Thus, the Werdi 'R' Actuator maintains a constant
outflow of product from the container.
There are four types of the Werdi 'N' Nozzle, which are used for dif-
ferent spray rates and patterns. When a nonaerosol (or aerosol) container is
filled to 65 volume percent with low-viscosity concentrate and then pres-
surized with air or nitrogen to 85 psig (6 bars), the results are as shown in
Table 50.
Werdi also makes complete valves as well as nonaerosol (pump-type)
containers, but their primary contribution to nonaerosol dispenser technology
appears to be in the actuator area, -The following U.S. Patents are reference
sources: 4,487,554 (ll-DEC-84), 4,260,110 (7-APR-81), and Battelle's
4,603,794 (5 AUG - 86). The last describes a dispenser able to deliver a high-
pressure spray by means of a low-pressure squeeze on the flexible sidewall
area, following a pressure multiplying principle.
Latest reports suggest that a large Northern Italian watchmaking firm is
interested in purchasing Werdi because they have facilities to produce many of
the very small actuator and other parts required for the system.
MISCELLANEOUS AEROSOL ALTERNATIVES
A number of dispensers can be used to present products that compete with
the aerosol system, although they may bear no direct similarity to aerosols.
Two will be considered in the following pages.
Insecticide Vaporizers
Vaporizers of various types have been used to provide "true aerosol"
mists or condensation nuclei of products in the air. For the most part, they
have been used for insecticides, but triethylene glycol mists of hexylresor-
cinol and other health-related products have enjoyed a much smaller market.
210
-------
TABLE 50. SPECIFICATIONS--USING FOUR NOZZLES--FOR THE WERDI 'R' ACTUATOR
Nozzle
Color Code
Type A
White
Type B
Yellow
Type C
Green
Type D
Black
Average
Delivery Rate
(mL/sec.)
Average
particle Size
(microns)
Cone Angle of
Spray Pattern
Cone Length
(inches)
Range of
Applications
0.70
. 50°
30
Personal
Deodorants
Pre-shaves
Leaf Polish
Mold
Releases
0.47
30°
24
Hair Spray
Wound Spray
1.30
0.7 - 3a
40°
55
Space
Insecticide
Air
Fresheners
1.30
25 - 50
30°
36
Polishes
Surface
Insecticide
Surface
Disinfectants
aThe average particle size for Types A, B, and C appear to be unusually low
for air sprays.
211
I
-------
In Latin America, Spain, Portugal, Tripoli, and other areas the electri-
cally vaporized insecticide products form the largest single use for insecti-
cide applications. Individual insecticide wafer sales volumes are greater
than the total aerosol markets in these countries. Such well-known firms as
S.C. Johnson & Son, Inc., Refinacoes de Milho, Brasil, Ltda (STP Brands),
Bayer, GmbH (BAYGON Brands), and Reckett & Coleman, Ltd. (Various Brands) sell
the wafers.
The wafer, which contains a few drops of absorbed insecticide con-
centrate, is placed in a holder on the heater, which is then connected to a
wall plug of electric current. The wafer is gently warmed to release the
insecticide materials. Although nontoxic at low levels of usethe insecti-
cides irritate mosquitoes (and "permilongos"--long-legged mosquitoes) so that
they leave the room. Especially useful in sleeping quarters, the wafer has
useful service life of from eight to ten hours. Foil packs of these products
are now being replaced with PET-laminate packs to reduce packaging costs.
Stick Products
Coming into major use only about ten years ago, the stick-in-canister
option has become the leading alternative for antiperspirants and personal
deodorants. A much smaller market exists for other items such as stick insect
repellents, stick spot-cleaners for textiles, stick analgesics (methyl
salicylate types, for example), and several other products.
Several types of polyethylene and polypropylene round and oval canisters
exist. The most popular are in the 1.5- to 3.5- Av.oz. (42.5 to 99.2 g) size,
with a bottom-entering plastic screw that, when rotated, elevates the product
so that it protrudes sufficiently from the top of the canister to allow for
convenient use.
A typical stick antiperspirant formulation contains 20 to 25% of the
aluminum chlorohydrate complex salt, compared with 7 to 12.5% in aerosol
products. Two representative formulas appear in Table 51.
212
-------
TABLE 51. TWO STICK ANTIPERSPIRANT FORMULAS
Antiperspirant Stick
Improved Antiperspirant Stick Formula
Ingredient/CTFA Name
Phase A
Pemethyl 99Aa Isododecane
Permethyl 10lAa Isohexadecane
Dow Corning 244b Cyclo-
methicone
Fluid A/PCPPG-14 Butyl Ether
Phase B
Crodacol S-95c Stearyl
Alcohol
Castorwax MP-80d Hydrogenated
Castor Oil
Phase C
Micro-Ace P-2a Talc
Phase D
Spheron P-1500s Silica
Phase E
Micro Dry6
hydrate
Aluminum Chloro-
17,15
4.00
13.15
11.50
11.50
7.50
10.50
2.00
22.00
Manufacturing Procedure: Add Phase
A in order to vessel, heat to 70-
75°C. Mix until clear and uniform.
While mixing, add Phase B one item
at a time. Continue mixing until
clear and uniform. Maintain 70 to
75°C, add Phase C, keep agitation
vigorous. Add Phase D, mix for 5-
10 minutes. Pour into containers
at 66-68°C.
Ingredient/CTFA Name %
(A) Cyclimethicone 43.5
Stearyl Alcohol 23.0
PPG-15 Stearyl Ether
(ARLAM0L E) 5.0
(ICI Specialty Chemicals)
(B) Hydrogenated Castor Oil 2.0
Stcareth-20 (BRIJ 78) 1.0
(ICI Specialty Chemicals)
(C) Silica 0.5
Aluminum Chlorohydrate 25.0
Procedure: Heat (B) to approximately
65°C until liquid. Add (A) with
moderate agitation and heat to minimize
silicone evaporation. Add (C) and stir
5-10 minutes until uniform. Cool to
55°C with stirring and pour into stick
forms.
Suppliers:
aPresperse Inc.
bDow Corning
cCroda
dCas Chem
®Reheis
213
-------
All significant marketers of aerosol underarm products also sell the
stick products. Each line generally has two sizes and "scented" and
"unscented" versions. Product effectiveness is equivalent to, or somewhat
higher than, those of the latest generation of aerosols, and the "anti-
perspirancy" of both versions is well above FDA requirements.
The antiperspirant type of underarm product commands 81% of the total
underarm aerosol business, and 83% of the stick alternative. The personal
deodorant subsegment is presented in the same container types and sizes.
Instead of aluminum astringent salt, it contains 0,1 to 0.2% of a germicidal
material, typically Triclosan, a diphenyl derivative made by Giba-Geigy
Corporation. Table 52 shows approximate production volumes of aerosol and
stick underarm products.
Other packaging forms, including roll-ons and pads, make up a relatively
minor proportion of the U.S. market. These secondary alternates will not be
covered here.
Aerosol and stick underarm products are mature markets. The change in
ratio shown in Table 52 is the result of new antiperspirant entrants (Bristol-
Myers and Metinen) whose advertising helped both their products and the aerosol
packaging concept. In addition, reformulation to more powerful forms of the
aluminum chlorohydrate have made aerosol antiperspirants more effective.
Unless significant changes in price structure, ecological aspects, f lam-
mability considerations, or other criteria affect one product at the expense
of the other, the 1:1.50 ratio of aerosols to sticks will-probably continue
for a long time. No dramatic changes are seen xn this ratio for at least four
years.
214
-------
TABLE 52. PRODUCTION UNITS OF UNDERARM PRODUCTS (U.S.)
Year
Aerosols
Sticks
Ratio
1986
153,000,000
258,000,000
1:1.69
1987
164,500,000
278,000,000
1:1.69
1988
193,000,000
292,000,000
1:1.51
1989a
207,000,000
310,000,000
1:1,49
Estimated figures at mid-1989.
215
-------
SECTION 3
SUMMARY
Part I of this report discusses the aerosol industry's experience in
converting from CFG propellants to alternative aerosol formulations. Some of
the immediately available alternatives, such as HCFC-22 and 1,1,1-
trichloroethane, also can deplete stratospheric ozone levels, although their
ozone depletion potentials are less than those of the CFC propellants.
Such compounds as HCFC-123, HCFC-124, HFC-125, HCFC-132b, HCFC-133a, HFC-
134a, and HCFC-141b are now undergoing extensive toxicological testing that
will continue until about 1992, Many of these "future alternative" compounds
are nonflammable unless they are mixed with substances such as iso-butane or
ethanol; others are flammable. Hydrocarbon propellants, which cost less than
CFCs, are often the propellants of choice unless special properties such as
increased solvency or reduced flammability are needed. Dimethyl ether (DME)
is the next most preferred CFC alternative. DME is flammable and a strong
solvent.
Carbon dioxide, nitrous oxide, and nitrogen are inexpensive and widely
available throughout the world but have been underused as aerosol propellants.
Special equipment is often needed to add them to the aerosol containers.
As CFC suppliers in the U.S., Western Europe, Japan, and other parts of .
the world develop their CFC phase-down programs, which will go beyond the
Montreal Protocol, they will be focussing on rapid commercialization and
application of the HCFC and HFC alternatives. . The major alternative will be
HFC-134a, which will replace CFC-12 in refrigeration, freezant, and air
conditioning systems.
216
-------
A variety of alternative aerosol packaging forms has been discussed in
Part II, with a special focus on those most like regular aerosols in
characteristics. All the alternatives have subsidiary positions in the
marketplace, if the volume of each is compared with the 3,000,000,QQO-unit
volume of aerosols. Several have been available for many years but have not
significantly penetrated the market for several reasons, shown below:
They generally cost more (finger-purops and sticks are exceptions).
They are limited in their product compatibility.
They depend on chemical or mechanical (often manual) action to
generate pressures needed to discharge the contents.
Products must be delivered as very coarse streams, pourables, paste
ribbons or (sometimes) post-foaming gels -- without having the broad
range of the aerosol presentation.
Sterility is generally impossible.
Sprays can deteriorate during use.
Several are incompletely tested.
Several require capital expenditures for special filling or gassing
equipment.
Sizes are limited to the 3-fl.oz. to 12-fl.oz. (119- to 355-mL)
range (some are even more limited).
In general, the packaging alternatives continue to be niche-fillers,
working best for a very limited range of products. Sales volumes are expected
to grow to some extent, however, taking some market share away from aerosols
217
-------
in selected areas, but without significantly affecting the aerosol business if
the present mix of political, regulatory, economic, environmental, financial,
and other issues remains reasonably static.
218
-------
APPENDIX "A*
METRIC (SI) CONVERSION FACTORS
Quantity To Convert Form To Multiply By
Length:
in
cm
2.54
ft
m
0.3048
Area:
in2
cm2
6,4516
ft2
m
0.0929
Volume:
m
cm5
16.39
ft1
ID
0.0283
gal
m3
0.0038
Mass (weight);
lb
kg
0.4536
oz
kg
0.0283
short ton (ton)
Mg
0.9072
short ton (ton)
metric ton (t)
0.9072
Pressure;
atm
kPa
101.3
mm Hg
kPa
0.133
psig
kPa
6.895
Psig
kPa*
((psig)+14.696)x(6
Temperature:
°F
°c*
(5/9)x(*F-32)
°C
K*
"C+273.15
Caloric Value:
Btu/lb
kJ/kg
2.326
Enthalpy;
Btu/lbmol
kJ/kgmol
2.326
kcal/gmol
kJ/kgmol
4.184
Specific-Heat
Btu/lb-°F
kJ/kg-°C
4.1868
Capacity:
Density;
lb/ft*
kg/m}
16.02
lb/gal
kg/m3
119.8
Concentration:
oz/gal
kg/Q
quarts/gal
cm'/ra5
25.000
Flovrate:
gal/min
m3/min
0.0038
gal/day
m3/day
0.0038
ft3/min
m'/rain
0.0283
Velocity:
ft/min
m/min
0.3048
Viscosity:
centipoise (CP)
Pa-s (kg/m-s)
0.001
'Calculate as indicated
219
------- |