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United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/S2-89/062 Feb. 1990
x°/EPA Project Summary
Aerosol Industry Success in
Reducing CFC Propellant Usage
Thomas P. Nelson and Sharon L. Wevill
Part I of this report discusses the
U. S. aerosol industry's experience In
converting from chlorofluorocar-
bon(CFC) propellents to alternative
aerosol formulations. Detailed ex-
amples of non-CFC formulations are
provided for 28 categories of aerosol
products. Hydrocarbon propellents,
which cost less than CFCs, are most
often selected as the propellents of
choice unless special properties
such as increased solvency or
reduced flammablllty 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 prepellants. 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 cha-
racteristics. Advantages and draw-
backs 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.
This Project Summary was
developed by EPA's Air and Energy
Engineering Research Laboratory,
Research Triangle Park, NC, to
announce key findings of the
research project that is fully
documented in a separate report of
the same title (see Project Report
ordering information at back).
Introduction
Since the early 1970s, scientists have
recognized the need to reformulate
aerosol products into compositions that
no longer contain chlorofluorocarbons
(CFCs). Once in the stratosphere, CFCs
are bombarded with high-energy
radiation from the sun, which splits off
chlorine atoms that then react with ozone
molecules, reducing them to ordinary
oxygen. Although ozone is reformed by
natural processes, the overall effect has
been one of ozone depletion.
In 1987, a treaty known as the
Montreal Protocol was developed and
ultimately ratified by 36 nations plus the
European Community (EC) calling for the
orderly reduction of CFC production
according to the following schedule:
• ByJuly 1, 1989: reduction to the 1986
average consumption level, based on
ozone depletion potential (OOP);
• By July 1, 1993: reduction to 80% of
the 1986 average level, OOP basis;
and
• By July 1, 1998: reduction to 50% of
the 1986 average level, OOP basis.
However, results of stratospheric
studies conducted since the Montreal
Protocol show that the original reduction
plan is not sufficient to prevent further
ozone depletion. Also, some of the
chemicals currently available to replace
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CFCs, such as HCFC-22 and 1,1,1-
trichloroethane, can also deplete
stratospheric ozone, although their ODPs
are less than those of the CFCs.
Future potential alternatives to CFCs
such as HCFC-123, HFC-l34a, and
HCFC-141b are currently undergoing
extensive toxicological testing that will
probably continue until 1992. Some of
these compounds are nonflammable, but
others are flammable and may not be
appropriate for use in certain aerosol
products. In the U.S., hydrocarbon
propellants may be used unless special
properties such as reduced flammability
and better solvent action are required.
Dimethyl ether (DME), one preferred
CFC alternative, is flammable, a strong
solvent, and highly water soluble; it can
be used to incorporate water into solution
in aerosol products such as hair sprays
and personal deodorants. Table 1
compares the physical properties of non-
CFC aerosol propellants.
Carbon dioxide, nitrous oxide, and
nitrogen are inexpensive and widely
available throughout the world, but they
have not been used much as aerosol
propellants since special equipment is
often required to add them to the aerosol
containers. Table 2 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 and relatively low price
(5 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% or less in
formulas and to include suppressive sol-
vents or other propellants to keep the
aerosol pressure from being excessive.
An interesting blend of HCFC-22/HCFC-
I42b (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 up to about 28%
propellant, its ethanol 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 pro-
pellant, except that it is flammable. It is
less flammable than hydrocarbon gases,
however, and it has been used with
(typically) 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. Its
composition is: 60.9% isobutane, 9.1%
propane, and 30.0% HFC-152a. Since the
pressure of the aerosol is about 154 psig
at 1300°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
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-152a is ap-
proximately 8 times the cost of hydro-
carbon propellants, the amounts used in
formulas are generally in the 2 to 10%
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 "CFC alternative"
propellants identified in Table 1 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 HCFC-141b and
HCFC-142b in 1989. A new plant has
been approved to produce large
quantities of HFC-134a by 1990. Small
lot quantities of HCFC-123 are already
available as a co-product from an existing
DuPont facility. And during 1988, DuPont
was issued a U.S. Patent on new
technology aimed at co-producing HCFC-
123 and HCFC-124 in a single process.
No schedules for HCFC-I24 produc
have been published, althougl
commercial-scale HCFC-123 plan
being built in Maitland, Ontario.
Other CFC suppliers in the U
Western Europe, Japan, and other p
of the world are also studying t
options for phasing out CFCs
commercializing various alternatives.
major alternative will probably be H
134a, since it will be used to repl
CFC-12 in refrigeration, freezant, anC
conditioning systems.
An imposing number of packac
alternatives to the standard aerc
dispenser are available. Several
aerosol containers, but segregate
propellant gas, and employ a fin;
pump, trigger-pump, hand-opera
piston action, a metal spring, sc
device, or other mechanism to dispe
the product or form the propellant
within the container as required. Otr
take the form of rather specialized, r
aerosol containers designed to enable
user to create air pressure or prod
pressure, or to operate screw-on, finj
pump or trigger-pump metering vaK
The pump-sprays, in all their dive
forms, represent the most widely u
alternative. Such packaging options
stick applicators and pads offer al
natives to the aerosol system but do
provide sprays; these are only brii
described in this report.
Many countries are now supporting
accelerated CFC phase-down progn
which goes beyond the 1987 Monti
Protocol and which is based on the ra
commercialization and application of
HCFC and HFC alternatives. Table 3 I
the aerosol products currently exemp
or excluded from the general regulat
bans in the U.S. on CFCs for aero
uses. They serve life-saving or ot
medical purposes or are considei
"essential" for other reasons.
Formulation Guidelines
A large number of characteristics m
be evaluated when considering p
pellants or propellant/solvent co
binations that may be used
reformulating CFC aerosols. Fla
mability, toxicology, solvency, cc
availability, solvate formation, solvol\
stability, dispersancy, pressure, a
compatibility are some of the essen
characteristics.
Apart from the CFCs, nonflamma
propellants consist of nitrogen, nitre
oxide, carbon dioxide, HCFC-22, anc
few blends of other propellants w
HCFC-22. Nonflammable propellants t
will be available in the future incli
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Table 1. Physical Properties of Non-CFC Aerosol Propettants
Vaoor Pressure (bar)
Product
n-Butane
i- Butane
Propane
Boiling Point
Formula ('C)
i-CjHfl -1 1
f* LJ A1
Cflg -42
zrc
1.20
2.17
7.60
55 "C
4.79
7.02
18.17
Density (g/mL)
21'C
0.580
0.559
0.503
Flammable
Range V.%
1.8-8.6
1.8-8.5
2.2-9.5
Dimethyl Ether
HCFC-22
HCFC-142b
HFC-1528
Carbon Dioxide
Nitrous Oxide
Nitrogen
(CH&O
CHCIF2
CH3-CCIF2
CH3-CHF2
C02
N2O
N2
-25
-41
-10
-25
-78
-88
-155
4.43
8.52
2.04
4.42
58.45
52.47
NIA
12.40
20.92
6.87
12.36
NIA
NIA
NIA
0.661
1.208
1.123
0.911
0.721
0.718
NIA
3.3-18.0
0
6.7-14.9
3.9-16.9
0
0
0
Future Propellants
HCFC-123
HCFC-124
HFC-125
HFC-134a
HCFC-141b
CHCI2-CF3
CHCIF-CF3
CHF2-CF3
CHjfF-CFj
CHy-CCIf
28
-11
-95
-32
33
-0.2
3.22
NIA
5.47
-0.3
1.7
8.8
NIA
14.3
1.2
1.470
1.368
NIA
1.203
1.231
0
0
0
0
6.4-15.1
NIA =Non Applicable, above Critical Temperature
Table 2. 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 speciality 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-pressurant for selected meter-sprayed vitamins and drugs.
HCFC-123, HCFC-124, HCFC-125, and
HFC-134a. The cost of HCFC and HFC
propellents will probably be about 20
times that of purified hydrocarbons by
1993 or 1994, which may limit their
application to relatively specialized
products, such as metered perfume
sprays in containers of 50 ml or less.
When flammable propellants are within
'he scope of company operations,
sobutane and propane are
currently the most reasonable choices. A
"natural blend" consisting, for example,
of 60% n-butane, 20% isobutane, and
20% propane can also be used.
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. Pressure limits for containers vary
little between countries. In the U. S., the
ordinary can holds product with
pressures up to 2,067 kPa abs. (9.85 bar-
gauge) at 54.4°C. Special cans with 14
and 28% higher pressure ratings are also
available at extra cost.
The formulator must test the
compatibility of the product with the
dispenser and packaging systems to
establish data on weight loss rates, can
and valve compatibility, organoleptic
stability, etc. Characteristics to look for
include corrosion, demulsification, color
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Table 3., 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, and coatings for electric
or electronic equipment
Meter-spray inhalant drugs:
a. Adrenergic bronchodilators
b. Cortico steroids
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% CFC product applications
or odor change, microbial proliferation,
precipitation, clogged valves, and
blistered dispenser lining. Thirty-six cans
per variable should be test-packed and
checked at 25 and 40°C, upright and
inverted.
Aerosol Packaging Alternatives
The variety of alternative aerosol
packaging forms available include bag-in-
can types, such as the Sepro can, which
separate the product from the propellant;
piston cans; independent bag-in-can
types; standard and aspirator pump
sprays; pressurizing dispensers; and
alternatives such as stick products.
Various dispensing closures are also
available.
Although several of these have been
available for many years, they have not
significantly penetrated the aerosol
market for the following reasons:
They generally cost more (finger-
pumps 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, 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- to 12-fl.oz
(119 to 355 mL) range. (Some are
even more limited.)
Sales volumes are expected to gr
however, taking some market share av
from aerosols.
The Sepro can may be operated
any position, since the bag is alw;
liquid-filled. As the product is used
the bag collapses upward in a control
way. Independent bag-in-can tyf
permanently separate propellant i
product. In the simplest form, a pla
pouch is inserted into an aerosol <
before or after filling with concentrate.
The most common pump sprayer
the finger-pump (as distinguished fr
the trigger pump) sprayer. Aspirator-t)
pump sprayers, such as the origi
insecticide sprayers, are the o
sprayers besides aerosols that c
produce a space spray.
Pressurizing dispensers use
pressure, the restorative pressure fr
an expanded rubber bladder, or a sim
arrangement, as the dispensing methoi
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T.P. Nelson and S.L. Wev/7/ are with Radian Corp.. Austin, 7X 78720.
N. Dean Smith is the EPA Project Officer (see below).
The complete report, entitled "Aerosol Industry Success in Reducing CFC
Propellant Usage," (Order No. PB 90-143 447/AS (Cost: $31.00, subject to
change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S2-89/062
000085833 PS
U S EKVIR PROTECTION AGEKCY
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CHICAGO IL 6060M
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