Propellant compositions comprising a hydrofluorocarbon and a hydrocarbon

Foaming propellant compositions for use in hair mousse compositions described. These compositions contain hydrofluorocarbon 152A and a suitable hydrocarbon in a ratio of about 30 to 70; to about 50 to 50; more preferably about 40 to 60. These compositions comprise the hydrofluorocarbon 152A; and a hydrocarbon, selected from the group consisting of propane, isobutane, and n-butane in the above recited ratios. The above propellant mixture is about 4 to 9 wt. % of total foaming, hair care composition.

FIELD OF THE INVENTION
 This invention relates to the development of superior foam characteristics
 of foaming propellant compositions such as mousse products
 BACKGROUND OF THE INVENTION
 In the formulation of foaming aerosol products, an essential component is
 the propellant which is used to dispense the liquid concentrate. In
 manufacturing, the liquid concentrate is first filled into the aerosol can
 which is sealed with a valve cup and then the propellant is introduced via
 pressure filling. It is also possible to do under the cup filling where
 the propellant is filled and the valve cup sealed in one step. Commonly
 used propellants in the formulation of personal care products can be
 classified into two major groups: Compressed gases and Liquefied
 propellants.
 Compressed Gases
 Examples of compressed gases are nitrogen, carbondioxide, etc., which
 remain as gases in the aerosol can. Depending on the type of concentrate
 used, they can be partially solubilized in the liquid concentrate. The
 pressure that results from such a product can be controlled by the amount
 of propellant that is solubilized in the liquid concentrate and what is
 left in the head space. Compressed gases are not widely used in personal
 care products since the pressure drops over the life of the can when it is
 being used resulting in different spray characteristics, lower spray rates
 and poorer foam quality. However the advantage of compressed gases is that
 they are inexpensive compared to liquefied propellants.
 Liquefied Propellants
 They are so called because they are gases under normal temperature and
 pressure but become liquids under higher atmospheric pressure. The
 advantage of using liquefied propellants is that they maintain a constant
 pressure throughout the life of the can by converting from a liquid state
 to a gaseous state as the can is depleted. This provides the user with a
 product that does not vary too much in its properties. Commonly used
 liquefied propellants are hydrocarbons, hydrofluorocarbons and
 dimethylether. Fluorocarbons were the most widely used propellants up
 until the mid 1970's when their use was restricted because they were
 alleged to damage the ozone layer. Hydrocarbons are now the propellant of
 choice because they are readily available and are less expensive than
 hydrofluorocarbons. Hydrocarbons used in the personal care industry are
 usually mixtures of Isobutane, n-butane and propane. These three are
 blended to give the desired pressure. For example, hydrocarbon A-46 is a
 mixture of 15.1% by weight of propane and 84.9% by weight of isobutane
 blended to give 46 psig pressure at 70 F. If lower pressures are desired,
 then the propellants are used as is. For example, n-butane has a pressure
 of 17 psig at 70 F. and Isobutane has a pressure of 31 psig at 70 F. which
 can be used without blending.
 Hydrofluorocarbons belong in the liquefied propellant group but are not
 widely used because of their expense. The most commonly used
 hydrofluorocarbon is Dymel 152A manufactured by Dupont. Dymel 152A has a
 pressure of 62 psig at 70 F. which makes it desirable for a number of
 applications. In hair sprays for example, this pressure is lowered by its
 solubility in the alcohol base which gives an even soft spray and in hair
 mousses, it is used to give a rich dense foam. Dymel 152A is also denser
 than hydrocarbons which is an advantage when filling cans to a desired
 weight.
 Dimethyl ether is another good propellant. Unlike hydrocarbons, it is
 extremely soluble in water. It is also reasonably priced and as a result
 has found its place in water based hair spray formulations. Its use in
 mousses as a sole propellant is limited due to high solubility.
 Formulation Considerations
 In the formulation of mousse products, the choice and amount of propellant
 used plays a major role in the quality of the foam produced. The two
 propellants that are currently used in the U.S. are Dymel 152A ( known as
 Dymel 152 and 152A, available from E. I. Dupont, Wilmington, Del.) and
 Hydrocarbon A-17(n-butane). Formulation parameters that make these two
 propellants attractive are: Pressure of the finished product, which should
 be such that the amount dispensed is in an acceptable range and the
 product can be packaged in a suitable can. The density of the formulation
 which determines how much weight percent of the active that can be
 dispensed each time. The quality of the foam is also a function of the
 type of propellant used--Dymel 152A gives a rich dense foam while
 hydrocarbon foams are more airy. The amount of propellant used in hair
 mousse formulations is typically between 4-9% by weight. At propellant
 levels higher than 9% by weight, the foam produced is dry whereas at lower
 levels below 4% the foam is not dense and runny.
 Although other ingredients in the formulation also play a role in the
 quality of the foam especially the level and type of surfactant used, it
 could generally be stated that Dymel 152A as a propellant has advantages
 over hydrocarbon dispensed products in producing a rich foam, and a dense
 foam which carries with it a higher active level. On the other hand, its
 disadvantages are is its cost and the resultant product has a higher
 pressure requiring it to be packaged in a more expensive can to meet
 department of transportation regulations.
 The problem that this invention has attempted to solve is how to get all of
 the advantages of the Dymel 152A propelled product to combine with all of
 the advantages of the hydrocarbon while keeping the cost of the finished
 product and the can to be at its lowest level.
 In brief, the present invention is directed towards producing a mousse
 product composition that is dispensed with a particular ratio of
 Dymel/hydrocarbon propellant to maximize its foam quality while minimizing
 the cost of the product and the can it is packaged in.
 Accordingly, it is an object of this invention to produce a foam that is
 rich in quality but yet at the same time is less expensive and can be
 packaged acceptably without using an expensive quality can.
 The invention provides a propellant composition having low vapor pressure,
 good foaming properties.
 A propellant composition that is lower in vapor pressure is safer to use
 and handle and can be dispensed from lighter, less expensive containers.
 Another measure of propellant is the foam which it produces. A preferred
 foam will be creamy feeling and looking and will have a slippery feel. An
 added advantage is if the propellant can produce a shiny foam. These
 characteristics are all achieved by the present invention.
 SUMMARY OF THE INVENTION
 The present invention pertains to foaming propellant compositions for use
 in hair mousse compositions containing hydrofluorocarbon 152A and a
 suitable hydrocarbon in a ratio of about 30 to 70; to about 50 to 50; more
 preferably about 40 to 60.

DETAILED DESCRIPTION OF THE INVENTION
 The propellant compositions of the invention comprise 152A and a suitable
 hydrocarbon in ratios that range from about 30:70 to 50:50; more
 preferably about 40:60.
 Suitable hydrocarbons include propane, isobutane, n-butane and mixtures
 thereof. Most preferably, the hydrocarbon employed is n-butane.
 Compositions of the invention preferably contain a mixture of
 anionic/nonionic surfactant/emulsifiers. The compositions of the invention
 may also contain cationic surfactants as long as the cationic surfactants
 are compatible with any anionics that may be present. The present
 invention relates to alcoholic and non-alcoholic foaming propellant
 compositions.
 Compositions of the invention may contain a surfactant or emulsifier such
 as a mild anionic surfactant or amphoteric surfactant.
 Preferred mild anionic and amphoteric surfactants used in this invention
 include: alkyl glyceryl ether sulfonate (AGS), anionic acyl sarcosinates,
 methyl acyl taurates, N-acyl glutamates, acyl isethionates, alkyl
 sulfosuccinate, alkyl phosphate ester, ethoxylated alkyl phosphate esters,
 alkyl sulfates, protein condensates, mixtures of ethoxylated alkyl
 sulfates and alkyl amine oxides, betaines, sultaines, and mixtures
 thereof. Alkyl chains for these surfactants are C.sub.8 -C.sub.22,
 preferably C.sub.10 -C.sub.18.
 Emulsifiers may be added to the formula to improve the phase stability of
 the concentrate, however, they are not necessary for a stable aerosol
 product that would be shaken before use.
 Emulsifiers can be selected from the group consisting of polyethoxylated or
 propoxylated C.sub.8 -C.sub.22 fatty acids, alcohols or glycols having
 less than about 30 moles of ethylene oxide per mole of fatty acid,
 ethoxylated esters, unethoxylated sugar esters, polyoxyethylene fatty
 ether phosphates, fatty acid amides, phospholipids, polypropoxylated fatty
 ethers, acyl lactylates, polyethoxylated poly (oxypropylene) glycols,
 polypropoxylated poly (oxyethylene) glycols, poly (oxyethylene) poly
 (oxypropylene) ethylene di-amines, and mixtures thereof.
 Examples of such emulsifiers include polyoxyethylene (8) stearate, myristyl
 ethoxy (3) palmitate, methyl glucoside sequestrate, sucrose distearate,
 sucrose laurate, sorbitan monolaurate, polyoxyethylene (3) oleyl ether
 phosphate, polyoxyethylene (10) oleyl ether phosphate, lauric
 diethanolamide, stearic monoethanolamide, lecithin, lanolin alcohol
 propoxylates, sodium stearol-2-lactylate, calcium stearoyl-2-lactylate and
 the Pluronics offered by BASF Wyandotte.
 Perfumes may be used in such products, generally at a level of about 0.1%
 to about 1% of the concentrate to cover the base odor. Colorants may also
 be used. Opacifiers, e.g., ethylene glycol distearate, polystyrene latex,
 generally at a level of about 0.2% of the concentrate, may also be used to
 provide the mousse with an opaque or pearlescent appearance.
 Preservatives, e.g. EDTA, methyl paraben, propyl paraben, Germall 115,
 Kathon, generally at a level of less than 1% of the concentrate, may be
 incorporated in the emulsion to prevent microbiological growth.
 The following examples are typical of the foaming propellant compositions
 of the present invention. These examples are presented for purposes of
 illustration only, and are not intended as a limitation on the scope of
 the invention as described herein.

Ingredients Formula A Formula B Formula C Formula D
 Water D.I. 90.1895 90.1895 92.0060 92.0060
 Polyurethane 0.7065 0.7065 0.6 0.6
 Gafquat 755N 8.6 8.6 7.0 7.0
 Sodium Cocoyl 0.054 0.054 0.054 0.054
 Isothionate
 Luaramid DEA 0.01 0.01 0.01 0.01
 Isosteareth 10 0.082 0.082 0.082 0.082
 Kathon CG 0.054 0.054 0.054 0.054
 DMDM Hydantoin 0.054 0.054 0.054 0.054
 Fragrance 0.1 0.1 0.1 0.1
 AMP 0.15 0.15 0.04 0.04
 Propellants 70 dymel Hydrocarbon 70 dymel 40 dymel/
 /30 hydrocarbon /30 hydrocarbon 60
 hydrocarbon
 Formulas A, B and C above are not within the scope of the present
 invention. Formula D above is within the scope of the present invention.
 Formulas above were prepared using the following procedure.
 Manufacturing Procedure
 Take Deionized water into a clean tank. Heat the batch to 90 F. Turn
 agitation to high. Slowly sift Polyurethane Resin into the tank. Mix until
 uniformly dispersed, approximately 30 minutes. Increase the temperature to
 131 F. (55 C.). When the temperature is 131 F. add AMP. Mix for 30 minutes
 to dissolve completely. When solution is clear add Isosteareth 10 and mix
 until completely dissolved (approx. 15 minutes). Turn heat off and cool
 the batch to 90 to 100 F. Add the following items and mix until uniform
 after each addition: Sodium Cocoyl Isothionate, Lauramide DEA, Gafquat
 755N, Kathon CG, DMDM Hydantoin, and Fragrance.
 Fill the above liquid concentrate into the aerosol can, sealed with a valve
 cup and then introduce the propellant via pressure fill or under the cup
 filling.
 As has been stated an object of the invention is to produce a propellant
 composition which may be used in a standard strength tube (or a 2N can)
 can rather than an expensive (2Q)can. In the table just below are listed
 the characteristics of the different types of cans. The cost of a "2Q" can
 may be 25% greater than the cost of a "2N" can. Thus the fact that the
 propellant foaming compositions of the present invention allow for the use
 of a "2N" can provide great cost savings in the manufacture of canned
 foamed propellant compositions of the claimed invention.

Pressure at 130 F. &lt;140 psi 140-160 psi 160-180 psi
 DOT Can 2N 2P 2Q
 Regulation
 (Type of can)
 Price Least Mid High
 Propellant Hydrocarbon 40/60(dymel/HC)
 70/30(dymel/HC)
 Performance Hydrocarbon:
 70/30(dymel/HC)
 (Finished Product) Preferred among value brand users
 Preferred among
 40/60:
 representative
 Preferred among representative samples
 which
 samples which includes premium includes
 premium
 brand user brand user
 DOT = Department of Transportation; 2N is a standard strength tube.
 As has been stated, an object of the invention is to produce a mousse
 product with a foam that is rich in quality, but yet at the same time is
 less expensive and can be packaged acceptably without using an expensive
 quality can. In fact, a 2N type can, which is the least expensive type of
 can in the above table, may be used with the compositions of the
 invention. The type and level of emulsifiers/surfactants employed can also
 result in further lowering of the pressure of the final product. If the
 pressure of the final product is low enough, a less expensive can may be
 used.
 It should be expected that when the percentage of 152A is decreased the
 quality of the foam produced will also decrease and that the creamy,
 slippery, shiny appearance will be replaced by the stiffer, more brittle
 foam produced by the hydrocarbon. However, at the 40:60 ratio, extensive
 market research showed that compositions of the invention were received
 favorably by both the value and premium brand users.
 In order to determine the acceptability of various types of mousse products
 among users, extensive market research studies were done with hydrocarbon
 and 152A/hydrocarbon mousse products. Users of these products fall into
 two groups--those that prefer the hydrocarbon products and those that
 prefer the 152A/hydrocarbon products. Those that prefer the hydrocarbon
 products are in the value segment of the market where the price of the
 product is an important consideration, while those that prefer the
 152A/hydrocarbon products are in the premium market segment where price is
 not as important as the quality of the product. Extensive market research
 further showed that compositions of the invention which comprised a 40:60
 ratio of 152A/hydrocarbon were received favorably by both the value and
 the premium segment of the market, by providing a product with good foam,
 that was packaged in an inexpensive can.