\ I /
                   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

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