Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1999-06-25
2001-09-18
Gorr, Rachel (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S591000, C528S049000, C528S071000, C528S079000
Reexamination Certificate
active
06291580
ABSTRACT:
FIELD OF THE INVENTION
This invention pertains to hair fixative compositions comprising polyurethanes containing pendant free carboxyl groups neutralized with standard cosmetically acceptable bases, and to a process for preparing polyurethanes.
BACKGROUND OF THE INVENTION
Polyurethanes have been used for a wide variety of applications. Since the early 1970's aqueous polyurethane dispersions have expanded in utility. The incorporation of ionic salt groups into the polyurethane prepolymer before dispersing into water greatly facilitates the formation of the aqueous polyurethane dispersion. Aqueous polyurethane dispersion technology has matured considerably; however, the basic polyurethane in the polyurethane dispersion is the result of reacting a diisocyanate, a diol or diamine (polyether, polyester, etc.) and a hydroxyl or diol (or amine analogue) molecule containing an ionic salt group. The ionic salt groups most often used are carboxylic, sulfonic and phosphoric acids (or the base neutralized acids), amine (or acid neutralized amine), or quaternary nitrogen groups. One of the most often used carboxyl reactants is dimethylol propionic acid.
Aqueous polyurethane dispersions have been used extensively as adhesives and coatings on essentially any synthetic or natural substrate such as paper, wood, cotton, leather, wool and hair. Specific applications in the pharmaceutical, cosmetic and hair fixative areas have been disclosed. Recently hair fixative applications have focused upon using hard polyurethanes which have a glass transition, Tg, above about room temperature. These hard, high Tg polyurethanes are used to provide the hold and curl retention necessary for hair fixatives but suffer from unpleasant, hard aesthetic feel on hair and brittleness of the polyurethane which results in flake development, raspy feel, or difficult to comb properties.
Most hair fixative compositions contain a film-forming polymer, which acts as the fixative, and a delivery system, which is usually an alcohol or a mixture of alcohol and water. In the case of aerosol delivery, the delivery system will also contain a propellant, which is typically a volatile hydrocarbon. Due to environmental regulations controlling the emission of volatile organic components (VOCs) into the atmosphere, these alcohol and hydrocarbon delivery systems are becoming less acceptable, and it is foreseen that water will become a greater component in hair fixative compositions. In addition, several different delivery systems for hair fixatives are now utilized, for example hair sprays, both aerosols and pumps, gels and mousses. Hair fixative polymers taught for use in aqueous based systems are known, for example, those disclosed in Japanese publication JP 47-46332. However, many of these exhibit a loss of performance properties in aqueous systems, for example, curl retention and on-hair stiffness are inferior, and in other cases the solution viscosity increases, and if delivered by aerosol, the composition foams at the valve actuator and on the hair. In addition, current systems may also exhibit poor compatibility with aqueous delivery systems. Overall the requirements for hair fixatives have increased. Performance requirements for hair fixatives now demand that the hair fixative polymer maintain a high degree of hold, gloss, curl retention, stiffness, and humidity resistance, but yet have pleasing aesthetics with a natural soft feel with no adhesive tackiness, no raspiness or brittle feel, no flake development and yet be readily removable. These factors have prompted the search for better performing hair fixative polymers that are soluble or dispersible in aqueous or in low VOC systems, that is, systems containing 80% or less VOCs. Current systems do not provide this required balance of properties.
U.S. Pat. No. 5,626,840 discloses polyurethanes prepared from an organic diisocyanate, a diol with a number average molecular weight greater than 1000, and a 2,2-hydroxymethyl-substituted carboxylic acid which are neutralized with a cosmetically acceptable organic or inorganic base and formulated into a hair fixative composition containing low amounts of volatile organic solvent.
SUMMARY OF THE INVENTION
The invention is directed to a process for preparing polyurethanes and to the use of polyurethanes in hair fixative compositions. The hair fixative composition of the present invention comprises a water soluble or dispersible polyurethane that, despite its solubility or dispersibility in water, also demonstrates good hold and flexibility, good compatibility with aerosol propellants, good spray characteristics, curl retention, stiffness, nontackiness, and forms a clear, transparent, glossy film that is easily removable with water (good rinsability) or with water and shampoo.
The hair fixative composition comprises (a) an effective amount of the polyurethane to perform as a hair fixative in an all water, alcohol-water, or allorganic system; (b) an effective amount of a cosmetically acceptable organic or inorganic base to neutralize a sufficient proportion of the available carboxyl groups on the polyurethane to make the polyurethane soluble or dispersible in water or in a mixture of water and an organic diluent; and (c) a diluent comprising (i) water, or (ii) water and 0 to about 90% by weight of an organic solvent, based on the weight of the solvent, or (iii) organic solvent.
In order to achieve the balance of required properties, we have found that two different components with active hydrogen atoms, one contributing rigidity and the other contributing flexibility to the polymer backbone, in addition to the carboxylic acid diol, are needed for the preparation of the polyurethane. Prior art has neither taught nor recognized the need for multiple polyols in the preparation of polyurethane hair fixatives with the above balance of properties.
The polyurethane is a fully reacted carboxylated polyurethane prepared as the reaction product of (i) one or more 2,2-hydroxymethyl-substituted carboxylic acids present in an amount to give 0.35 to 2.25 milliequivalents of carboxyl functionality per gram of polyurethane, (ii) 5 to 90% by weight, based on the weight of the polyurethane, of one or more organic components, other than the 2,2-hydroxymethyl-substituted carboxylic acids, each having at least two active hydrogen atoms, and (iii) one or more organic diisocyanates present in a sufficient amount to react with the active hydrogens of the 2,2-hydroxymethyl-substituted carboxylic acids and the organic components, excepting the hydrogen on the carboxylate of the 2,2-hydroxymethyl-substituted carboxylic acid. Properties can be further enhanced by chain extension and chain termination.
The hair fixative composition may be used in sprays, aerosols, pumps, gels, mousses and lotions. In aerosol systems, the hair fixative composition will further comprise up to 60% by weight of a propellant based on the weight of the total hair fixative composition.
The present invention is also directed to a process for preparing polyurethanes wherein the dispersion is accomplished after at least 50%, but before completion, of the theoretical isocyanate reaction has taken place.
DETAILED DESCRIPTION OF THE INVENTION
The polyurethanes suitable for use in hair fixative formulations according to this invention are fully reacted carboxylated polymers. These polyurethanes are used in an effective amount to achieve the desired balance of properties, such as hold, curl retention, stiffness, and humidity resistance, pleasing esthetics with a natural soft feel with no adhesive tackiness, no raspiness, or brittle feel, no flake development and having rinsability. They are preferably present in amounts from 1 to 20% by weight of the hair fixative composition, and more preferably in amounts from 1 to 10% by weight.
The incorporation of the 2,2-hydroxymethyl-substituted carboxylic acid introduces pendant carboxylic acid groups into the polymer chain, which after neutralization render the polyurethane soluble or dispersible in water or in mixtures of water with other polar solve
Kielbania, Jr. Andrew J.
Kukkala Pravin K.
Lee Sharon P.
Vitale Melissa J.
Gorr Rachel
Kaiser Karen G.
National Starch and Chemical Investment Holding Corporation
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