MXPA00012361A - Alkali soluble latex thickeners - Google Patents

Abstract

Alkali soluble thickeners are dislcosed which comprise a reaction product of (A) an unsaturated carboxylic acid monomer, (B) a monoethylenically unsaturated monomer different from monomer (A), and (C) a hydrophobic, alkoxylated macromonomer polymerizable with monomers (A) and (B). The monoethylenically unsaturared monomer different from monomer (A) comprises a methyl group, preferably is an acrylate and more preferably is methyl acrylate. The polymers disclosed solubilize at a pH of from about 4.5 to 6.0, thereby rendering the polymers particularly suitable for use in cosmetic compositions.

Description

LATEX THICKNESS, SOLUBLE IN ÁLCALI Field of the Invention The present invention relates to latex polymers, which are soluble in alkali and, more specifically, to latex polymers which demonstrate an increase in viscosity at a pH of less than about 6.

Background of the Invention As used herein, the term "alkali soluble thickeners" means latex polymers, which become soluble in an aqueous medium by adding a sufficient amount of a base to raise the pH to an effective level, and thus causing the latex polymer to become soluble in the aqueous medium. Alkali-soluble thickeners have found great acceptance in industrial applications, such as, for example, use in coating compositions, for example latex paints. Such alkali-soluble thickeners are described, for example, in US Patents Nos. 4,514,552, issued April 30, 1985; 4,722,962, issued February 2, 1988 and 5,292,828, issued March 8, 1994. Such alkali-soluble thickeners typically comprise the reaction product in aqueous emulsion of (A) a monoethylenically unsaturated carboxylic acid, for example methacrylic acid; (B) a monoethylenically unsaturated monomer, different from monomer (A), for example ethyl acrylate; and (C) a macromonomer, comprising a hydrophobic portion and an alkoxylated portion, which is polymerizable with the monomer (A) and the monomer (B). Often, the macromonomer is a urethane monomer, which is the reaction product of the urethane of a monohydric surfactant, and a monoethylenically unsaturated monoisocyanate. Typically, the monohydric surfactant comprises an ethoxylated or propoxylated aliphatic or alkylphenol alcohol. Traditionally, the alkali-soluble thickeners, as described above, begin to solubilize and demonstrate an increase in viscosity at a pH greater than 6.0 and often in the approximate range of 6.5 or greater. Maximum viscosity is often not achieved until a pH of 7.5 or higher is achieved. Therefore, such alkali-soluble thickeners have not found wide acceptance in personal care applications, for example in hair care and skin care compositions, since personal care compositions typically require a significant increase in the viscosity, at or below the pH of the skin, for example from about 6.5 to 6.8.

Therefore, improved alkali soluble thickeners are desired, which can demonstrate an increase in viscosity at a pH of less than about 6.0.

SUMMARY OF THE INVENTION By means of the present invention, it is now possible to provide alkali-soluble latex polymers, which are suitable for use in personal care applications, for example hair care compositions and care of hair. the skin. The polymers of the present invention comprise the reaction product of (A) an unsaturated carboxylic acid monomer, (B) a monomer, monoethylenically unsaturated, different from (A), and (C) a macromonomer, comprising a hydrophobic portion and an alkoxylated portion, which is polymerizable with the monomer (A) and the monomer (B). Very surprisingly, according to the present invention, it has been found that, when the monomer (B), monoethylenically unsaturated, comprises a methyl group, preferably methyl acrylate, the solubilization of the polymer occurs at a pH of about 4.5 to 6, thus making the polymer suitable for use in personal care applications. Furthermore, it has been found, quite surprisingly, according to the present invention, that the use of a long-chain aliphatic alcohol in the preparation of the macromonomer, can provide a polymer having desirable properties of thinning cutting.

Detailed Description of the Invention The unsaturated carboxylic acid monomers, suitable for use in accordance with the present invention, are typically α, β-monoethylenically unsaturated carboxylic acids. Preferred carboxylic acid monomers are selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and mixtures thereof. Methacrylic acid is especially preferred. The concentration of the carboxylic acid monomer is typically from about 20 to 70 weight percent, preferably from about 20 to 50 weight percent and, more preferably, from about 35 to 45 weight percent, based on the total weight of the polymer. The amount of the carboxylic acid monomer is preferably sufficient to supply a polymeric structure which will solubilize and provide an increase in viscosity, when reacted with an alkali, such as, for example, sodium hydroxide. In accordance with the present invention, the monoethylenically unsaturated monomer, other than monomer (A), is one comprising a methyl group. Preferably, this monomer is an acrylate. More preferably, this monomer is methyl acrylate. Typically, the amount of the monoethylenically unsaturated monomer, other than monomer (A), is about 20 to 80 weight percent, preferably about 30 to 65 weight percent, and more preferably about 45 to 55 percent. by weight, based on the total weight of the polymer. Macromonomers suitable for use according to the present invention comprise a hydrophobic portion, an alkoxylated portion and which can be polymerized with the monomer (A) and the monomer (B). As used herein, the term "macromonomer" means a polymerizable monomer, which comprises the reaction product of two or more compounds. Said macromonomers include, for example, any alkoxylated monomer, for example ethoxylated or propoxylated, having an ethylenic unsaturation and which is terminated by a hydrophobic fatty chain. Examples of polymerizable, unsaturated moieties include those selected from the group consisting of vinyl, methacryloyl, maleoyl, itaconoyl, crotonyl, one part unsaturated urethane, maleoyl half ester, itaconyl half ester, CH2 = CHCH2-0- groups. , methacrylamido and substituted methacrylamido. Examples of the hydrophobic moieties include those selected from the group consisting of alkyl, alkaryl, ie alkylaryl or aralkyl, or aryl, linear or branched, saturated or unsaturated, and having at least 6 carbon atoms, preferably about 6 carbon atoms. 30 carbon atoms per molecule. Preferred macromonomers are the urethane monomers, which comprise the reaction product of a monohydric surfactant and a monoethylenically unsaturated isocyanate. Preferably the urethane monomer is a non-ionic urethane monomer, which is the reaction product of the urethane of a monohydric, nonionic surfactant with a monoethylenically unsaturated monoisocyanate, preferably one lacking ester groups, for example, the alpha, alpha-dimethyl-m-isopropenyl-benzyl-isocyanate. The monohydric nonionic surfactants are themselves well known and are usually alkoxylated, for example ethoxylated, hydrophobic, containing an adduct of ethylene oxide, to supply the hydrophilic portion of the molecule. The hydrophobes are usually aliphatic alcohols or alkyl phenols, in which a carbon chain contains at least 6 carbon atoms, preferably around 6 to 30 carbon atoms, which supply the hydrophobic portion of the surfactant. These surfactants are illustrated by the adducts of ethylene oxide of dodecyl alcohol or octyl- or nonylphenol, which are commercially available and contain about 5 to 150, preferably 25 to 60 moles of ethylene oxide per mole. of the hydrophobe. Other hydrophobic substituents, such as the complex hydrophobes, described, for example, in U.S. Patent No. 5,488,180, issued January 30, 1996, are available for use in accordance with the present invention. In a preferred aspect of the invention, the hydrophobic portion of the surfactant comprises an aliphatic alcohol, containing about 20 to 24 carbon atoms. More preferably, the aliphatic alcohol is of vegetable origin. Even more preferably, the aliphatic alcohol is behenyl alcohol. Isocyanates, monoethylenically unsaturated, suitable for use in preparing the urethane monomers, can be any effective in forming the desired urethane linkage. Preferably, the isocyanate is a monoethylenically unsaturated monoisocyanate. Any copolymerizable unsaturation can be employed, such as the unsaturation of acrylate and methacrylate. One can also use an allylic unsaturation, such as that provided by allylic alcohol. This, preferably in the form of a functional hydroxy derivative, is obtained by reacting a C2-C4 monoepoxide, such as ethylene oxide, propylene oxide or butylene oxide, with acrylic or methacrylic acid, to form an ester of hydroxy, are preferably reacted in equimolar proportions, with an organic diisocyanate, such as toluene diisocyanate or isophorone diisocyanate. The preferred monoethylenic monoisocyanate is styryl, as in the isocyanate of alpha, alpha-dimethyl-m-isopropenyl-benzyl, and this unsaturated monoisocyanate lacks the ester group and thus forms urethanes lacking this group. The amount of the isocyanate, monoethylenically unsaturated, relative to the monohydric surfactant in obtaining the macromonomer (on a molar ratio basis) is typically from about 0.1-2.0 to 1, preferably from 1.0 to 1.0. Typically, the amount of the monomer (C) is about 0.5 to 60 weight percent, preferably about 5 to 50 weight percent, and, more preferably, about 5 to 15 weight percent, based on the total weight of the polymer. Typically, the molecular weight of the macromonomers ranges from about 400 to 8000 grams per mole gram. As used herein, the term "molecular weight" means the weight average molecular weight. The techniques for measuring this weight average molecular weight are known to those skilled in the art. One such technique is gel permeation chromatography. Further details relating to the preparation of said macromonomers are known to those skilled in the art and are described, for example, in US Patents Nos. 4,514,552, 4,801,671, 5,292,828 and 4,294,693. In addition to the specific monomers, described above, additional monomers can be used in the preparation of the polymers of the present invention. For example, a polyethylenically unsaturated monomer can be copolymerized in the polymer, as is common in alkali soluble emulsion copolymers. They are illustrated by ethylene glycol diacrylate or dimethacrylate, 1,6-hexanediol acrylate or dimethacrylate, divinyl benzene and the like. Further details relating to said additional monomers and other monomers suitable for copolymerization, according to the present invention, are known to those skilled in the art. Such additional monomers typically comprise from 0 to about 10 weight percent, based on the total weight of the polymer. One or more of each class of monomers, described above, can be used in the preparation of the polymers of the present invention. Also, in addition to the specific monomers within each class, those skilled in the art will recognize that other monomers, within said classes, may be used, in accordance with the present invention. Such monomers are generally available commercially.

The latex polymers of the present invention are prepared in colloidal form, ie in aqueous dispersions, and can be prepared by the emulsion polymerization, in the presence of a chain transfer agent and an initiator. Specific details relating to the procedures and conditions for emulsion polymerization are known to those skilled in the art. See, for example, US Patent No. 5, 629, 375, issued May 13, 1997. However, typically the polymerization is carried out in an aqueous medium, at a temperature of about 35 to 90 °. C. The pressure is not critical and is dependent on the nature of the monomers used. Chain transfer agents are not normally used in polymerization. However, when chain transfer agents are employed, they are typically present during the polymerization reaction at a concentration of about 0.01 to 5 weight percent, preferably about 0.1 to 1 weight percent, based on the content of the total monomer. Chain transfer agents both insoluble in water and water soluble can be used. Illustrative of the substantially water-soluble chain transfer agents are the alkyl and aryl mercaptans, such as butyl mercaptan, mercaptoacetic acid, mercaptoethanol, 3-mercaptol-l, 2-propanediol and 2-methyl-2- propanothiol. Illustrative of chain transfer agents, substantially insoluble in water, include, for example, t-dodecyl mercaptan, phenyl mercaptan, pentaerythritol tetramercatopropionate, octyldecyl mercaptan, tetradecyl mercaptan and 2-ethylhexyl-3-mercaptopropionate. In carrying out the emulsion polymerization, an initiator at a concentration sufficient to initiate the polymerization reaction is preferably used. It will typically vary from about 0.01 to 3 percent by weight, based on the weight of the charged monomers. However, the concentration of the initiator is preferably about 0.05 to 2 weight percent and, more preferably, about 0.1 to 1 weight percent of the charged monomers. The particular concentration used in any case will depend on the specific monomer mixture that is subjected to the reaction and the specific initiator employed, these details are well known to those skilled in the art. Illustrative of suitable initiators include hydrogen peroxide, peracetic acid, t-butyl hydroperoxide, di-t-butyl hydroperoxide, dibenzoyl peroxide, benzoyl hydroperoxide, 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl- 2, 5-bis (hydroperoxy) -hexane, perbenzoic acid, t-butyl peroxypivalate, t-butyl peracetate, dilauroyl peroxide, dicapriloyl peroxide, distearoyl peroxide, dibenzoyl peroxide, diisopropyl peroxydicarbonate, didecyl peroxydicarbonate, di-icosyl peroxydicarbonate, di-t-butyl perbenzoate, 2,2'-azobis-2, -dimethylvaleronitrile, ammonium persulfate, potassium persulfate, sodium persulfate, sodium perphosphate, azobisisobutyronitrile, like any other known initiators. Also useful are redox catalyst systems, such as sodium persulfate - sodium formaldehyde sulfoxylate, t-butyl hydroperoxide - isoascorbic acid, t-butyl hydroperoxide - sodium bisulfate, sodium formaldehyde sulfoxylate, eumeno hydroperoxide - sodium metabisulfite, hydrogen peroxide - ascorbic acid, and other known redox systems. Also, as those skilled in the art know, trace amounts of metal ions can be added as activators, to improve the polymerization rate, if desired. The particular surfactant, useful in conducting the polymerization reaction, is not critical in the present invention. Typical surfactants include the anionic surfactants, such as sodium lauryl sulfate, sodium tridecyle sulfate, diester sulfosuccinates and the sodium salts of the alkyl aryl polyether sulfonates; and nonionic surfactants, such as alkyl aryl polyether alcohols and ethylene oxide condensates of propylene oxide, propylene glycol adducts. Preferably, the initiators and surfactants are selected to minimize the odor of the final product. The reaction products, which comprise the latex polymers of the present invention, typically have a solids content, ie the polymer, of about 10 to 65 weight percent, preferably about 20 to 50 weight percent , based on the weight of latex and water. Typically, the particle size of the latex polymer is from about 0.1 to 1.0 miera. The glass transition temperature (Tg) of the latex polymers of the present invention is typically around 20 to 60 ° C. As used herein, the term "Tg" means the transition temperature to glass. The techniques for measuring the glass transition temperature of polymers are well known to those skilled in the art. One such technique is, for example, differential scanning calorimetry. A particularly useful resource in estimating the glass transition temperature of a polymer is given by the Fox equation: l / Tg (polystyrene) = X? / Tg? + x2 / Tg2 + x3 / Tg3 * ... + xn / Tgn (I) where x ± is the weight fraction of component i in the copolymer and Tgi is the glass transition temperature of the homopolymer of component i. The glass transition temperatures of the homopolymer can be found in any available public source, such as the Polymer Handbook. Typically the viscosity of the latex polymers of the present invention is from about 5 to 1500 centipoise ("cP") in the unneutralized form, measured at 20 ° C with a composition of 20 to 50 weight percent solids, using a Brookfield viscometer, with a number 2 shaft at 60 revolutions per minute. The molecular weight of the latex polymers of the present invention is typically from about 104 to 107, preferably about 200,000 to 1,000,000 grams per mole gram. In accordance with the present invention, the latex polymers become soluble in the aqueous medium, at a pH of less than about 6.0, preferably at a pH of about 4.5 to 6.0 and, more preferably, at a pH of about 5.0 to 6.0. . A significant stabilization, ie, 90% maximum viscosity, preferably occurs at a pH of about 7.5 or less, more preferably at a pH of about 7.0 or less. The solubilization is effected by the introduction of a suitable alkali, such as, for example, sodium hydroxide, potassium hydroxide, ammonium hydroxide, amines, for example triethylamine, and other alkaline materials known to those skilled in the art. In the solubilization of the latex polymers, the viscosity of the aqueous medium shows a significant increase. Preferably, according to the present invention, the aqueous compositions, comprising the solubilized polymers of the present invention, have a viscosity of greater than about 10,000 cP, preferably greater than about 20,000 cP, more preferably greater than about 40,000 cP, and especially preferred greater than about 60,000 cP, at a pH less than about 6.0. Unless stated otherwise, the viscosity measurement of the solubilized polymer is taken at a polymer concentration of 1.0 weight percent, based on the total weight of the aqueous composition, using a Brookfield LVT DV viscometer. II, at 20 ° C, using an axle No. 3, at 12 rpm. Very surprisingly, according to the present invention, it has been found that by using a straight chain aliphatic alcohol, having about 20 to 24 carbon atoms, such as hydrophobe, in the manufacture of the macromonomer, the polymers of the present invention, in their solubilized state they have convenient cutting thinning characteristics. Note the following data in Table 1 below.

TABLE 1 Spindle speed (rpm) Viscosity, cPs 0.3 1658550 0.6 895220 1.5 396200 3. 0 213860 6.0 115430 12.0 62300 30.0 27575 60.0 14885 In general, the polymers of the present invention are particularly effective as thickeners, i.e. they increase the viscosity in aqueous compositions. Typically, the amount of the polymer used to achieve the thickening efficiency is about 0.05 to 5 percent by weight, based on the total weight of the composition. The specific amount of the polymer will be dependent on the particular end use and can be determined by those skilled in the art.

Also, other ingredients, such as, for example, surfactants, preservatives, co-thickeners, such as, for example, the polysaccharide ethers, solvents and other materials known to those skilled in the art, can be employed in the compositions of the present invention. The polymers described herein are useful in a variety of aqueous systems, such as textile coatings (fabrics and non-wovens), formulations of latex paints, cosmetic formulations, dispersions of pigments and aqueous pastes, dentifrices, hand lotions, liquid detergents, refreshing, agricultural chemicals, concrete additives, transmission fluids, wastewater treatment (flocculants), turbulent drag reduction, automatic coatings (OEM and re-finishes), architectural coatings ,. industrial coatings, and the like. Other applications include, for example, papermaking, mineral processing, brine viscosification, superabsorbency, enhanced oil recovery, personal care products, biomedical, pharmaceutical and the like. The polymers of the present invention are particularly suitable for use in personal care compositions, for example hair care and skin care compositions. Traditional compositions for personal care comprise the polymer of the present invention, water and a suitable ingredient for personal care. As used herein, the term "personal care ingredient" includes, but is not limited to, active ingredients, such as, for example, spermicides, virucides, analgesics, anesthetics, antibiotic agents, antibacterial agents, antiseptic agents, vitamins, corticosteroids, anti-fungal agents, vasodilators, hormones, antihistamines, autacoids, querolitic agents, anti-diarrhea agents, anti-alopecia agents, anti-inflammatory agents, glaucoma agents, compositions for dry eyes, agents for healing wounds, exfoliating agents , sunscreens, antioxidants, enzymes, anti-infection agents, and the like, as well as solvents, diluents and auxiliaries, such as, for example, water, ethyl alcohol, isopropyl alcohol, higher alcohols, glycerin, propylene glycol, sorbitol, preservatives, surfactants, entol, eucalyptus oil, other essential oils, fragrances, agents that adjust the visc Os, polymers in addition to those of the present invention, and the like.

These other polymers include, for example, neutral, cationic, anionic and amphoteric polymers, occurring naturally and synthetically, for example the polysaccharide ethers, hyaluronic acid, polyalkylene oxides and polycarboxylic acids. Polysaccharides include polymers of naturally occurring, biosynthesized carbohydrates and derivatives, or mixtures thereof. These materials include high molecular weight polymers, composed of monosaccharide units, linked by glycosidic bonds. These materials may include, for example, whole starch and cellulose families; pectin, chitosan, chitin, seaweed products, such as Irish agar and moss, alginates, natural gums, such as guar, gum arabic and tragacanth; bio-derived gums, such as xanthan, and the like. Common polysaccharides include cellulosics, conventionally employed in the preparation of cellulose ethers, such as, for example, chemical cotton, cotton wool, wood pulp, alkaline cellulose and the like. These materials are commercially available. The molecular weight of polysaccharides typically varies from approximately 10,000 to 2,000,000 grams per mole gram. Preferably, the polysaccharides are etherified by the reaction of the polysaccharide with an alkylene oxide, for example ethylene oxide, propylene oxide or butylene oxide. The amount of ether substitution is typically about 1.5 to 6 and preferably about 2 to 4 moles of the ether substituent per mol di ether of polysaccharide. The polysaccharide ethers may be substituted with one or more desired substituents, for example cationic, anionic and / or hydrophobic substituents. Hydrophobic substituents are known in the art, examples of which are described above. Hydrophobically modified cellulose ethers are described, for example, in US Patents Nos. 4,228,277, 5,120,328 and 5,504,123 and European Patent Publication 0 384 167 Bl. Cationic cellulose ethers, hydrophobically modified, are described, for example, in U.S. Patent No. 4,663,159. The level of substitution of such substituents in the polysaccharide ether is typically from about 0.001 to 0.1, and preferably about 0.004 to 0.05 moles of the substituent per mole of the polysaccharide ether. Preferred polysaccharide ethers, for use according to the present invention, are cellulose ethers, including, for example, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, carboxymethyl cellulose, hydroxyethyl carboxymethyl cellulose, and their derivatives.

Such personal care ingredients are commercially available, for example, from Amerchol Corporation, Edison, NJ. Further details regarding the selection and quantities of such personal care ingredients are known to those skilled in the art. Typical personal care compositions, in accordance with the present invention, may, for example, contain the following ingredients, with the proportions listed below as the active weight percent. The ingredients are listed as the names of the International Nomenclature of Cosmetic Ingredient ("INCI"), which can be found, for example, in the International Cosmetic Industrial Dictionary, 6th Edition, Cosmetic Toiletries and Fragrances Association (1995).

TYPICAL FORMULATIONS Mus (foam) for conditioning the skin Ingredients% _____ __ Ether of PPG-10 methyl-glucose 3.00 Deionized water c.s 100 PEG 14M 0.10 Polymer of the Invention 0.10 Aminomethylpropanol c.s pH = 5.5 Condoms q.s. SD Alcohol 40 15.00 Propellant A-46 Hydrocarbon 4.00 c.s. = sufficient amount Mus (foam) for conditioning / hair styling Ingredients% Dimethicone Copolyol 1.00 PVP / VA copolymer 2.00 Polyquaternium-24 0.30 Deionized water cs 100 Polymer of Invention 0.125 Aminomethylpropanol cs pH = 5.5 SD Alcohol 40 15.00 Propellant A-46 Hydrocarbon 4.00 Styling Gel Ingredients Deionized water cs 100 Polymer of Invention 1.25 PVP / VA Copolymer 4.00 Triethanolamine q.s. pH = 5 Methyl Gluceth-20 5.00 Condoms q.s.

Color c.s.

Hand Lotion Ingredients% Mineral Oil 8.00 Cetyl Acetate / Alcohol 1.00 Acetylated Lanolin Glyceryl Stearate 0.50 Sesquistearate of methyl- 3.00 glucose Sesquistearate of methyl- 2.00 glucose of PEG-20 Dimethicone 0.50 Deionized water c.s 100 Methyl Gluceth-10 0.50 Polymer of Invention 0.20 Condoms q.s. 100 Triethanolamine q.s. pH = 7.0 Spray Gel (sprinkled) Ingredients Deionized water c.s 100 Polymer of the Invention 0.30 Methyl Gluceth-20 4.00 Dimettjicone Copolyol 2.00 Triethanolamine q.s. pH = 5, PVP / VA Copolymer 5.00 Activator of the Rizado Ingredients Deionized water c.s. 100 Polymer of Invention 0.50 Glycerin 10.00 Propylene glycol 5.00 Methyl Gluceth-10 5.00 Condoms q.s.

Triethanolamine q.s. pH = 6.0 Shampoo Ingredients Deionized water c.s. 100 Ammonium laureth sulfate 10.00 Lauryl-ammonium sulfate 5.00 Cocamida MEA 3.00 Coco-betaine 1.00 Polymer of Invention 1.0 Dimethicone 1.00 Deionized water 10.00 Polyquaternium-10 0.30 Triethanolamine c.s pH = 6.5 Condoms c. s Rinse Cream Ingredients Cetearyl Alcohol (y) 4.00 Ceteareth-20 Cetyl Alcohol 1.00 Polysorbate 80 0.50 Deionized water c.s. 100 Polymer of Invention 0.50 Triethanolamine q.s. pH = 6.0 Laurl-methyl-Gluceth-10 1.00 Hydroxypropyl Diammonium Condoms c.s, The invention is described below with reference to the Examples, which are not intended to limit the appended claims. The following Examples are illustrative of the preparation of the non-ionic urethane monomers of this invention.

EXAMPLE 1 (Preparation of a Urethane Monomer) To a one liter glass reactor, equipped with a thermometer, heating blanket, thermoregulator, stirrer, nitrogen spray and condenser, including a Dean-Stark trap, 800.0 g were charged of 40 moles of behenyl alcohol ethoxylate as a hot melt. The contents of the reactor were heated, with nitrogen spraying, to 110 ° C and maintained for two hours, while traces of moisture were removed and collected in the Dean-Stark trap (typically less than 1 g). The contents of the reactor were then cooled to 80 ° C, the Dean-Stark trap was replaced with a condenser and the nitrogen spray was changed to an air spray for 15 minutes. With the continuous air spraying, 0.01 g of the methoxy-hydroquinone inhibitor, 0.50 g of the dibutyltin dilaurate catalyst and 81.0 g of the alpha, alpha-dimethyl-m-isopropenylbenzyl isocyanate (m-) were charged to the reactor. TMI, a product of Cytec Industries, Inc., Stamford, CT, can be used). After a rapid initial exothermic reaction, which increased the reaction temperature by about 8 ° C, the contents were heated to maintain 80 ° C for two more hours. The product was then cooled to room temperature. The final product is a white wax in appearance, with a residual isocyanate content of less than 0.5% and with 98% of the original ethylenic unsaturation retained.

EXAMPLE 2 (Preparation of an Alkali Soluble Thickener, with the Urethane Monomer) To a three-liter flask, equipped with thermometer, stirrer, condenser, nitrogen inlet, thermoregulated water bath and monomer addition pump, were charged 989.0 g of deionized water and 4.0 g of 2-sulfoethyl methacrylate. The water was heated to 80 ° C and purged with nitrogen for 30 minutes. A pre-mixture of monomers was prepared in a separate stirred vessel, charging, in order, 171.0 g of methacrylic acid, 203 g of methyl acrylate, 21.0 g of sodium dioctyl sulfosuccinate, Triton GR-9M, a surfactant, a product from Union Carbide Corporation (sodium lauroyl sulfate can be used as an alternative) and 56.0 g of ethoxylated urethane monomer, prepared in Example 1. Under a blanket of nitrogen, 45.0 g (10%) of the premix of monomers were charged to the reactor, followed by 36 g of 1% sodium persulfate, a 3% solution of sodium bicarbonate. %. The contents produced an exothermic reaction at about 85 ° C and then cooled again to 80 ° C. The addition of the remaining premix was initiated and progressively continued for 2.5 hours until complete. The contents of the reactor were heated for a further 30 minutes at 80 ° C, to complete the conversion of monomers to the copolymer and then cooled to 60 ° C, at this point 2.0 g of a 6 wt% solution of t-hydroperoxide. Butyl was added, followed by 2.0 g of a 6 wt% solution of isoascorbic acid in 15 minutes, to purify the residual monomer below 2 ppm by weight. The product is a low viscosity latex with a solids content of 25.1%, a Brookfield RVT viscosity of 19 cps (axis No. 1 at 100 rpm), pH of 2.5 and an average particle size of 92 nanometers ("nm") ).

EXAMPLE 3 Control Preparation of the Alkali Soluble Thickener, Which Has an Ethyl Group with the Urethane Monomer A polymer was prepared, according to the procedure set forth in Example 2, with the exception that the ethyl acrylate was replaced with the acrylate. of methyl, mentioned in Example 2. The product is a low viscosity latex, with a solids content of 25.0%, a Brookfield RTV viscosity of 19 cps (Axis No. 1 at 100 rpm), pH of 2.6 and a size average of 92 nm particles.

EXAMPLE 4 pH Viscosity Dependence The polymers, prepared in Examples 2 and 3, were treated with various amounts of an alkaline material, for example 10% NaOH, and the viscosity was measured as a function of pH. Said viscosity was measured using a Brookfield Viscometer LVT DV-II, with a # 3 axis, at a concentration of 1.00 weight percent of the polymer at 20 ° C and a speed of 12 rpm. The results are shown in the following Table 2.

TABLE 2 Dependence of the pH It can be seen from the data presented in Table 2, that, quite surprisingly, the replacement of the ethyl acrylate with the methyl acrylate in the polymer of the present invention results in a substantial reduction in the pH necessary to achieve the increase in the viscosity of the aqueous composition Although the present invention has been described with respect to the specific aspects, those skilled in the art will recognize that attempts are made to include other aspects within the scope of the following claims.

Claims (18)

1. CLAIMS 1. A polymer, which comprises the reaction product of: (A) an unsaturated carboxylic acid monomer; (B) a monomer, monoethylenically unsaturated, different from monomer (A); and (C) a macromonomer, comprising a hydrophobic portion and an alkoxylated portion, which can be polymerized with the monomer (A) and the monomer B); characterized in that: (i) the monomer (B), monoethylenically unsaturated, comprises a methyl group; e (ii) the polymer has a viscosity of at least 10,000 cP, at a pH of less than about 6. 0
2. 2. The polymer of claim 1, wherein the hydrophobic macromonomer is a urethane monomer, comprising the reaction product of a monohydric surfactant and a monoethylenically unsaturated isocyanate.
3. 3. The polymer of claim 1, wherein the monomer (B) is an acrylate.
4. 4. The polymer of claim 3, wherein the monomer (B) is methyl acrylate.
5. 5. The polymer of claim 1, which comprises about 20 to 80 weight percent of the monomer (B), based on the total weight of the polymer.
6. 6. The polymer of claim 1, wherein the unsaturated carboxylic acid monomer is selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid and mixtures thereof.
7. 7. The polymer of claim 1, which comprises about 20 to 70 weight percent of the monomer (A), based on the total weight of the polymer.
8. 8. The polymer of claim 2, wherein the monohydric surfactant is an alkoxylated aliphatic alcohol or the alkylphenol.
9. 9. The polymer of claim 8, wherein the monohydric surfactant has the formula: R - O - (- CH2 - CHR ') m - (- CH2 - CH20) n - H wherein R is an alkyl group containing 6 to 30 carbon atoms or an alkaryl group, containing 8 to 30 carbon atoms, R 'is C 1 -C 4 alkyl, n is an average number of about 6 to 150, and m is an average number from 0 to 50, provided that n is at least as large as m, and that n + m = 6-150.
10. 10. The polymer of claim 2, wherein the monomer (C) is the reaction product of the urethane of the monohydric surfactant with the isocyanate of alpha, alpha-dimethyl-m-isopropenyl-benzyl.
11. 11. The polymer of claim 1, wherein the hydrophobic portion of the macromonomer is an aliphatic alcohol of vegetable origin.
12. 12. The polymer of claim 11, wherein the alcohol has approximately 20 to 24 carbon atoms.
13. 13. The polymer of claim 12, wherein the alcohol is behenyl alcohol.
14. 14. The polymer of claim 1, which comprises about 0.5 to 60 weight percent of the monomer (C), based on the total weight of the polymer.
15. 15. The polymer of claim 1, which comprises about 35 to 45 weight percent of the monomer (A), about 45 to 55 weight percent of the monomer (B) and about 5 to 15 weight percent of the monomer (C), based on the total weight of the polymer.
16. 16. A composition comprising the polymer of claim 1 and water.
17. 17. The composition of claim 16, further comprising at least one ingredient for personal care.
18. 18. The composition of claim 16, which has a viscosity of at least 20,000 cP, at a pH of less than about 6.0.