Drug – bio-affecting and body treating compositions – Effervescent or pressurized fluid containing – Organic pressurized fluid
Reexamination Certificate
1999-09-08
2002-04-09
Bawa, Raj (Department: 1619)
Drug, bio-affecting and body treating compositions
Effervescent or pressurized fluid containing
Organic pressurized fluid
C424S070100, C424S070160, C424S070230, C514S945000, C514S938000
Reexamination Certificate
active
06368575
ABSTRACT:
BACKGROUND
The present invention relates to aerosol or foam hair styling compositions delivered from metal containers and a method of inhibiting corrosion of the metal container holding the hair styling composition. More particularly, the present invention relates to a method of inhibiting corrosion to tin plate or aluminum aerosol cans caused by the hair spray composition without compromising performance of the hair spray product or without the expense of special can liners. In a preferred embodiment, the present invention also relates to non-corrosive aqueous hair styling compositions containing low (80 weight percent or less) volatile organic compound (VOC) concentrations.
Hair styling products, such as hair sprays, styling gels, spray gels and mousses are used on hair to hold the hair in place. The hair styling products, when applied, form a thin film or weld of resin on the hair, most efficiently in the seam between adjacent hair fibers or at a point where the fibers cross one another, and, as a result, hold the hair in a particular shape or configuration.
Hair styling products can be applied to the hair in several ways. One of the most desirable ways is to formulate the hair fixative resin under pressure in a system containing solvent and propellant. The resin is delivered to hair as a fine mist where the propellant is used to drive the product out of its container onto the hair. Typically, the container is a tin plated metal or aluminum can. Preventing the hair spray formulation from corroding the metal container during storage is a key parameter in formulating an aerosol hair spray suitable for the trade.
Legislation in New York, California and other states mandates that the amount of VOC formulated into hair styling products that are sprayed, such as aerosol and pump hair sprays, must not exceed 80 weight percent (%) in the product. By June 1999, the amount of VOC in hair styling products that are sprayed must be reduced to 55% in California. Other states have enacted similar legislation mandating the reduction of VOC in hair styling products that are sprayed. Present hair styling products in the United States that are sprayed typically have VOC levels of 80% or less. Such VOC include, for example, ethanol, dimethyl ether and hydrocarbons; the most likely replacement for VOC is water.
The introduction of water into the hair styling product accelerates corrosion kinetics (rate of corrosion). Corrosion is also accelerated by presence of certain additives, and reduced in the presence of other additives, called corrosion inhibitors (
Spray Technology
&
Marketing
, C. M. Rocafort, December, 1995). The presence of certain additives, such as those required to prepare a hair fixative resin (for example, emulsifiers, surfactants, chain transfer agents, initiators and redox agents) may accelerate corrosion to an extent that it cannot be inhibited even with a high concentration of corrosion inhibitors in the formulation or by increasing the pH. These additives, being part of the polymer processing package, cannot be removed or replaced without negatively affecting the ability to prepare the polymer.
The problem addressed by the present invention is to reduce the tendency of hair fixative resin formulations to corrode metal containers in aerosol formulations, particularly low-VOC formulations, without negatively affecting the performance of the hair styling product or its cost effectiveness, and without affecting the ability to prepare the hair fixative resin polymer in high yield with low residual monomer and in a form easily used by the hair styling composition formulator.
U.S. Pat. No. 4,196,190 discloses acrylic hair fixative resins containing 10-30% of an alkyl acrylate, 41-60% of methyl methacrylate, 5-20% of hydroxyethyl methacrylate and 10-30% of methacrylic acid. Although disclosing that water can be used in a hair styling composition containing the acrylic hair fixative resins, this reference does not disclose or suggest methods for overcoming the problems associated with hair styling compositions regarding corrosion. U.S. Pat. No. 5,658,558, although disclosing how to improve the performance of acrylic resins in low-VOC systems, also does not disclose how to overcome corrosion problems.
The use of phosphate esters as emulsifiers to prepare acrylic emulsion polymers is disclosed in “Phosphate Esters as Primary Anionic Emulsifiers for Acrylic Latex Synthesis” by N. Shachat and Y. Z. Li, at
Water
-
Borne
&
Higher Solids and Powder Coatings Symposium
, New Orleans, La. (USA), Feb. 24-26, 1993. GB Patent No. 2,203,156 discloses corrosion resistant compositions for metal surfaces coated with acrylic resin and organic phosphate/phosphite mixtures. Neither of these references discloses how to overcome the problems associated with aerosol hair styling compositions regarding corrosion.
The present invention seeks to overcome deficiencies of the prior art hair fixative resin technology by using hair fixative resins prepared by emulsion polymerization using selected emulsifiers as processing aids to minimize corrosion in the hair styling formulation while retaining other beneficial hair fixative properties.
STATEMENT OF INVENTION
One embodiment of the present invention provides an aqueous aerosol or foam hair styling composition comprising (a) from 1 to 15 weight percent of at least one acrylic hair fixative resin, based on total weight of the aqueous aerosol or foam hair styling composition, wherein the acrylic hair fixative resin is a polymer comprising as polymerized units from 2 to 100 weight percent of at least one (C
1
-C
12
)alkyl (meth)acrylate, based on total weight of the acrylic hair fixative resin; and (b) from 10 to 70 weight percent of at least one propellant, based on total weight of the aqueous hair styling composition; wherein the hair fixative resin is an emulsion polymer prepared in the presence of a phosphate ester emulsifier.
In another embodiment, the present invention provides the aforementioned aqueous aerosol or foam hair styling composition further comprising volatile organic compounds in a concentration up to 98 weight percent, based on total weight of the aqueous hair styling composition.
In a further embodiment, the present invention provides an improved method for inhibiting corrosion in an aqueous aerosol or foam hair styling composition as described as above, wherein the improvement comprises preparing the acrylic hair fixative resin by emulsion polymerization in the presence of a phosphate ester emulsifier.
DETAILED DESCRIPTION
The method of the present invention is useful for improving the corrosion resistance of aerosol or foam hair styling formulations when the hair styling formulation is provided in metal containers, such as aerosol cans. We have found that the use of certain selected emulsifiers, that is, phosphate esters, in the preparation of the emulsion polymer hair fixative resins surprisingly improves the corrosion resistance of the hair styling composition in metal containers without negatively affecting the performance of the hair styling product itself.
By an “aqueous hair styling composition” we mean a hair spray or mousse (aerosol or foam) that is used on hair to hold the hair in a particular shape or configuration. Preferably, the hair styling composition in the present invention is a hair spray.
As used herein, all percentages referred to will be expressed in weight percent (%) unless specified otherwise.
The aqueous hair styling compositions typically will contain at least 2% and up to 98% water, more typically, from 25 to 70% water, based on the total weight of the aqueous hair styling composition. By “low-VOC” we mean the hair styling composition contains 80% or less volatile organic compounds, that is, typically 10% or more of water. Preferably, the hair styling composition contains less than 70%, and more preferably 55% or less, VOC. Optionally, the hair styling composition may contain no VOC.
The term “(meth)acrylate” means methacrylate or acrylate. The term “(meth)acrylic acid” means methacrylic acid or acrylic acid.
Chang Ching-Jen
Keenan Andrea Claudette
Schwartz Curtis
Bawa Raj
Howell Thomas J.
Rohm and Haas Company
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