Abstract: This invention provides method of treating a surface of exterior wood outside of buildings to inhibit the uptake of moisture into the wood by spraying on the surface of the wood an aqueous formulation consisting of one or more film forming non-chloride, long-chain polymers. The aqueous formulation forms a clear micro-film. Preferably, the long-chain polymer is polyethylene-vinyl acetate, polyurethane, or a combination thereof, wherein the clear micro-film contains no detectable volatile organic compounds. A clear colorant is added to the aqueous formulation to verify treatment. The clear colored micro-film maintains moisture content in the wood at 16 percent or less, allows for continued visual inspection of the surface of the wood for termite damage, does not rub off, get diluted with water, or become damaged by workers and pets who come into contact with the clear colored microfilm.

Abstract: The present invention provides a coating agent for leather, the coating agent containing: in terms of solid content ratio, (I) an aqueous urethane resin; (II) a matting agent; and (III) a silicone acryl graft copolymer resin emulsion in which the weight ratio of a polyorganosiloxane represented by a specified formula relative to acrylic ester units or methacrylic ester units is 50:50 to 90:10, and a leather on which a coating by the coating agent for leather is formed. This coating agent for leather has exceptional wear resistance and anti-fouling properties, and a leather on which a coating by the coating agent is formed can maintain a high-quality external appearance and high wear resistance.

Abstract: The present invention provides for an emulsion comprising solid particles of a single composition, or a mixture thereof, comprising a polymer comprising one monomer of an aryl methacrylate, or a mixture thereof, co-polymerized with a monomer of an alkyl methacrylate, or a mixture thereof; wherein Ar is an aryl group and R is an alkyl group, and n:m has a ratio of from about 0:100 to about 100:0.

Abstract: The present invention provides a method for preparing a vinyl chloride-based polymer comprising performing suspension polymerization of vinyl chloride-based monomer, wherein an aromatic hydrocarbon-based compound is added when a pressure change is 0.5 to 1.5 kg/cm2 with respect to an equilibrium pressure at a polymerization temperature in a polymerization reactor after the vinyl chloride-based monomer is added to the polymerization reactor, wherein the aromatic hydrocarbon-based compound comprises a reactive functional group having an intracarbon double bond and a hydroxyl group; and a vinyl chloride-based polymer prepared by the method and having a high polymerization degree and excellent fusion processability.

Abstract: Water-redispersible polymer powder compositions having cationic functionality are prepared by radically polymerizing one or more ethylenically unsaturated monomers in the presence of a protective colloid and/or emulsifier in an aqueous medium, and drying the resulting aqueous polymer dispersion after addition of a catonic protective colloid as a drying aid, the cationic protective colloid comprising a homopolymer or copolymer of one or more cationic monomers having a quaternary ammonium halide group, with 50 wt % to 100 wt % of the halide ions in the quaternary ammonium halide groups having been replaced by nonhalide anions, and with the fraction of halide ions being less than 1 wt %, based on the total weight of the polymer powder composition.

Abstract: Water resistant, acrylic emulsion pressure sensitive adhesive polymers containing particles having a mean “volume-average” particle diameter of greater than about 210 nm for use in label and tape application are provided. The emulsion polymers exhibit an increase in opacity of less than about 10%.

Abstract: The present invention refers to developing and obtaining new composite materials based on rubbers and/or elastomers and/or their recycled can be reused through an in situ polymerization program between the combination of different monomers and/or oligomers type diisocyanate, esters, or organic peroxides cross-linking agent, which in their combination generate a binding agent capable of modifying the intrinsic chemical, thermal, rheological, and mechanical properties in the material and the chains chemical cross-linking originated by the incorporation of organic peroxides which are able to accelerate or decrease the reaction rate.

Abstract: A process for the preparation of dihalodiphenylsulfones_such as 4,4?-dichlorodiphenyl sulfone or 4,4?-bis-(4-chlorophenylsulfonyl)biphenyl with high regioselectivity, at low temperature and in the absence of toxic reagents by reacting together at least one acid, at least one fluorinated anhydride and at least one halobenzene. The invented process is particularly suited for the manufacture of 4,4?-dichlorodiphenyl sulfone.

Abstract: An additive for lead-acid battery including sulfonated polyacrylic acid aimed at extending the battery life by preventing the sulfation of the negative electrode, and a lead-acid battery using the additive.

Abstract: Disclosed herein is a block copolymer comprising a first block derived from a vinyl aromatic monomer; and a second block derived from an acrylate monomer; where a chi parameter that measures interactions between the first block and the second block is greater than or equal to about 0.05, when measured at 240° C. Disclosed herein too is a method comprising polymerizing a vinyl aromatic monomer to form a first block; and polymerizing a second block onto the first block to form a block copolymer; where the second block is derived by polymerizing an acrylate monomer; and where the block copolymer has a chi parameter of greater than or equal to about 0.05, when measured at 240° C.; where the chi parameter is a measure of interactions between the first block and the second block.

Abstract: A ball milling free and roll milling free process that includes the mechanical mixing of a mixture of ingredients comprising a polymer, a perfluoropolyether phosphate, a conductive component, and a solvent.

Abstract: Disclosed herein are polybutadiene grafted isoprene rubber, processes for preparing polybutadiene grafted isoprene rubber, mixed compositions and vulcanized forms thereof.

Abstract: An aqueous polymer composition is described comprising a homogeneous acrylic polymer dispersion produced by emulsion polymerization of a monomer mixture comprising: (A) from 85 to 99.9 wt % of one or more main monomers selected from C1-C12-alkyl esters of acrylic acid or C5-C12-alkyl esters of methacrylic acid, styrene, and vinyl toluene in such a ratio as to produce a polymer having a Tg in the range of ?20 to +65° C.; and (B) from 0.1 to 5 wt % of at least one stabilizing monomer selected from ethylenically unsaturated monocarboxylic acids or amides thereof, ethylenically unsaturated dicarboxylic acids or anhydrides or amides thereof, ethylenically unsaturated sulfonic acids, ethylenically unsaturated phosphoric acids, and ethylenically unsaturated phosphonic acids. The emulsion polymerization is conducted in the presence of 0.05 to 3 wt %, based on the total weight of monomers in the monomer mixture, of a chain transfer agent (C).

Abstract: A method for producing a water-absorbent resin including the step of subjecting a water-soluble ethylenically unsaturated monomer to a reversed phase suspension polymerization in a petroleum hydrocarbon dispersion medium in the presence of a radical polymerization initiator and a dispersion stabilizer, wherein the method is characterized by the use of an ether-ester type nonionic surfactant as the dispersion stabilizer, and a water-absorbent resin obtained by the method, wherein the water-absorbent resin has a water-retention capacity of saline solution of 25 g/g or more, a water-absorption rate of saline solution of 50 seconds or less, and a flow index under moisture absorption of 70% or more. According to the method of the present invention, a water-absorbent resin having high water-retention capacity, excellent water-absorption rate, and further having excellent flowability under moisture absorption can be produced.

Abstract: The present invention provides a (meth)acrylic resin composition comprising a carboxylic acid group produced by heating a (meth)acrylic-based resin (C), wherein the (meth)acrylic-based resin (C) is obtained by polymerizing a monomer mixture (A) containing 80 to 99 wt % of a linear alkyl (meth)acrylate and 1 to 20 wt % of tertiary-butyl (meth)acrylate, in the presence of an acrylic acid ester-based crosslinked elastic particle (B) that is obtained by mixing and polymerizing 0.5 to 5 parts by weight of a polyfunctional monomer having at least two non-conjugated double bonds per molecule, with respect to 100 parts by weight of a monomer mixture containing 50 to 100 wt % of an alkyl acrylate monomer and 0 to 50 wt % of an alkyl methacrylate monomer. This composition can be used to produce a film having excellent chemical resistance (in particular, sun-screening agent resistance).

Abstract: The present invention concerns a method for the dispersed phase polymerisation of halogenated vinyl compounds, having the formula RbRcC?CX1X2, where: X1?F or CI, X2?H, F or CI, each of Rb and Rc, separately represents: —H, CI, F; or—an alkyl group, preferably chlorinated and/or fluorinated, and more advantageously perchlorinated or perfluorinated, comprising a step (E1) wherein said monomers are introduced into an aqueous phase together with—at least one source of free radicals; and—at least one reactive stabiliser comprising a polymer chain and a thiocarbonylthio-S group (C?S)—, said polymer chain comprising non-(N vinyl lactam) monomer units.

Abstract: A non aqueous dispersion is disclosed containing: a shell polymer; a core polymer, and a continuous phase solvent, wherein said shell polymer is soluble and said core polymer is insoluble in the continuous solvent. Also disclosed is a method for improving the setting properties of a sheet fed offset ink by adding to the ink the above non aqueous dispersion.

Abstract: A finely divided, cationic, aqueous polymer dispersion, obtained by (I) solution polymerizing a first mixture containing (a) 15-40% by weight of a mixture of (a1) a (meth)acrylate and (a2) a (meth)acrylamide, (b) 40-85% by weight of styrene, (c) 0.5-5% by weight of an ethylenically unsaturated monomer, and (d) 0-20% by weight of a nonionic, ethylenically unsaturated monomer differing from (b); (II) adding water; and (III) emulsion polymerizing a second monomer mixture containing (i) 0-29% by weight of styrene, (ii) 50-100% by weight of a C1- to C18-(meth)acrylate, (iii) 0-30% by weight of a vinyl ester of a C1-C30-carboxylic acid, and (iv) 0-30% by weight of a nonionic ethylenically unsaturated monomer differing from (i), (ii), and (iii), wherein at least one of the solution and emulsion polymerizing are performed in the presence of 0-10% by weight of a regulator.

Abstract: A method for producing a water-absorbent resin by performing a reversed-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a petroleum hydrocarbon dispersion medium, comprising the following steps of: (A) performing a primary dispersion in the absence of surfactants by adding an aqueous solution of a water-soluble ethylenically unsaturated monomer containing a hydrophilic polymeric dispersion agent to a petroleum hydrocarbon dispersion medium in which a hydrophobic polymeric dispersion agent was heat-dispersed or heat-dissolved, under stirring; (B) further performing a secondary dispersion by adding a surfactant to a dispersion liquid obtained after the primary dispersion; and (C) performing the reversed-phase suspension polymerization by using a radical polymerization initiator; and the water-absorbent resin obtained by the method.

Abstract: Methods of synthesizing a binary polymer functionalized nanoparticle are generally provided. In one embodiment, a first anchoring compound is attached to a nanoparticle, and a first plurality of first monomers are polymerized on the first anchoring compound to form a first polymeric chain covalently bonded to the nanoparticle via the first anchoring compound. In another embodiment, a first polymeric chain can be attached to the nanoparticle, where the first polymeric chain has been polymerized prior to attachment to the nanoparticle. Thereafter, a second anchoring compound is attached to the nanoparticle, and a second plurality of second monomers are polymerized on the second anchoring compound to form a second polymeric chain covalently bonded to the nanoparticle via the second anchoring compound. Nanoparticles are also generally provided having multiple polymeric assemblies.

Abstract: A method for producing a water-absorbent resin including the step of subjecting a water-soluble ethylenically unsaturated monomer to a reversed phase suspension polymerization in a petroleum hydrocarbon dispersion medium in the presence of a radical polymerization initiator and a dispersion stabilizer, wherein the method is characterized by the use of an ether-ester type nonionic surfactant as the dispersion stabilizer, and a water-absorbent resin obtained by the method, wherein the water-absorbent resin has a water-retention capacity of saline solution of 25 g/g or more, a water-absorption rate of saline solution of 50 seconds or less, and a flow index under moisture absorption of 70% or more. According to the method of the present invention, a water-absorbent resin having high water-retention capacity, excellent water-absorption rate, and further having excellent flowability under moisture absorption can be produced.

Abstract: The invention relates to a method for producing hybrid-particles containing polymer and SiO2-particles, wherein a) in a first polymerization step in aqueous medium a water-insoluble phase containing one or more monomeric and colloidal SiO2-particles having an average particle diameter of 1 to 150 nm are polymerized, and b) in a second polymerization step in aqueous medium one or more monomers are polymerized in the presence of the polymer obtained in the first polymerization step.

Abstract: The present invention relates to a catalyst system, to a method of manufacturing this system, and also to uses of this system. The catalyst system of the invention is characterized in that it comprises molecules of a polymer having, at one of its ends or along the chain, one or more polar functional groups; a solvent, said solvent, due to the fact of said polar functional group of said polymer, provoking and maintaining, when said molecules of the polymer are introduced thereinto, an organization of said molecules of the polymer into aggregates, micelles or vesicles so that the polar functional groups of said polymer are located inside the aggregates, micelles or vesicles formed; and a catalyst activator and a catalyst trapped in said aggregates, micelles or vesicles of said polymer. The catalyst system of the present invention may be used, for example, for catalyzing a (co)polymerization of olefins.

Abstract: The present invention relates to a process for the production of the largest possible spherical, monodisperse polyvinylpyrrolidone (PVP) seed particles in the micron range by dispersion polymerisation. The particles obtained in this way represent novel starting materials for the production of macroporous polymer particles, which can in turn be employed in preparative and analytical chromatography for protein preparation. They can also be employed as base material for further reactions. The novel process for the polymerisation of N-vinylpyrrolidone, which is inexpensive to carry out, gives particles having optimised quantities, such as monodispersity, sphericity and particle diameter, which can be employed in further reactions and have advantageous, in particular improved, properties for use in chromatographic separation methods.

Abstract: Disclosed is a water-absorbent resin particle in which the water-absorption rate of physiological saline is 1 second to 15 seconds, the median particle size is 100 ?m to 600 ?m, and the residual volatile component content is 1.5% by weight or less.

Abstract: The present invention provides a (meth)acrylic resin composition comprising a carboxylic acid group produced by heating a (meth)acrylic-based resin (C), wherein the (meth)acrylic-based resin (C) is obtained by polymerizing a monomer mixture (A) containing 80 to 99 wt % of a linear alkyl (meth)acrylate and 1 to 20 wt % of tertiary-butyl (meth)acrylate, in the presence of an acrylic acid ester-based crosslinked elastic particle (B) that is obtained by mixing and polymerizing 0.5 to 5 parts by weight of a polyfunctional monomer having at least two non-conjugated double bonds per molecule, with respect to 100 parts by weight of a monomer mixture containing 50 to 100 wt % of an alkyl acrylate monomer and 0 to 50 wt % of an alkyl methacrylate monomer. This composition can be used to produce a film having excellent chemical resistance (in particular, sun-screening agent resistance).

Abstract: A process for making substantially uniform oligomeric droplets in an aqueous dispersion comprising preparing an aqueous emulsion of an emulsifying agent, at least one monomer, a chain transfer agent, and an initiator; and mixing the aqueous emulsion with a stabilizer and a plurality of seed particles.

Abstract: A process for producing water-absorbing polymer particles, comprising the addition of a solid additive to a polymer gel by means of a conveying screw (1), wherein the solid additive and a gas volume flow are fed to the conveying screw (1) by means of an addition channel (2).

Abstract: A description is given of the use of a polymer dispersion for preparing sound deadener compositions, the polymer dispersion being obtainable by emulsion polymerization of free-radically polymerizable monomers in the presence of at least one protective colloid which is an amphiphilic graft copolymer. Preferred protective colloids have a polyalkylene oxide main chain and vinyl ester-comprising side chains. A description is also given of corresponding sound deadener compositions which comprise the polymer dispersion, and of a method for damping oscillations or vibrations of vehicle components.

Abstract: An object of the invention is to provide a protein-adsorbing material having both adsorption capacity and high-speed treatment performance applicable to not only analysis use but also industrial use, in balance, and to provide a method for producing the same. The present invention provides a protein-adsorbing material comprising a polymer base-material, a polymer side-chain immobilized to the surface of the polymer base-material and a functional group having protein adsorption ability and immobilized to the polymer side-chain, in which the mass of the polymer side-chain is 5 to 30% relative to the mass of the polymer base-material.

Abstract: A composite catalyst useful in the production of polyethylene, which comprises at least a first catalyst and a second catalyst separated by a polymer layer, with the first catalyst and the second catalyst being identical or different, is described. A composite catalyst useful in the production of polyethylene with a broad molecular weight distribution in a single polymerization reactor, which comprises at least a first catalyst and a second catalyst separated by a polymer layer, with the first catalyst and the second catalyst being different, is also described. A process for preparing said catalysts and a process for the production of a polyethylene by using said catalysts are also described.

Abstract: A multi-stage aqueous emulsion polymer, an aqueous coating composition including the emulsion polymer, and a method for providing a coating including the emulsion polymer are provided. The multistage emulsion polymer includes from 10% to 30% by wt., based on the wt. of the multistage emulsion polymer, of a first polymer shell having an acid number of from 5 to 100, the first polymer having a calculated Mn of from 1000 to 4500 and a calculated Tg of lower then 100° C.; and from 70% to 90% by wt., based on the wt. of the multistage emulsion polymer, of a second polymer core having an acid number of from 0 to one-half the acid number of the first polymer, the second polymer having a calculated Mn of greater than 20,000.

Abstract: The present invention pertains to a process for the preparation of aqueous dispersions which are stabilized with a water-insoluble stabilizing colloid, characterized in that a) in a first step a water-insoluble stabilizing colloid is prepared, with this being prepared, based on the amount of monomer used for the preparation of the stabilizing colloid, by means of radical polymerization, followed by b) the addition of at least one further olefinically unsaturated monomer and at least one initiator, in which process by means of radical polymerization of the further olefinically unsaturated monomer an aqueous dispersion is obtained, on which c) optionally a residual monomer reduction is performed, with this being carried out by means of polymerization of residual monomers and/or by means of physical removal of the residual monomers and optionally further volatile organic components by means of the introduction of vapor and/or gas.

Abstract: The invention relates to a method for producing anionic water-in-water polymer dispersions containing at least one finely dispersed, water-soluble and/or water-swellable polymer A and a continuous aqueous phase. This phase has a partial quantity of at least one polymeric dispersing agent B in which monomers dispersed in this aqueous phase are subjected to a radical polymerization, and after the polymerization is completed, the reaction mixture is subsequently diluted with the remaining amount of dispersing agent B. The invention also relates to the polymer dispersions obtained according to the method and to their use, particularly in the paper industry.

Abstract: A method for producing a water-absorbent resin by performing a reversed-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a petroleum hydrocarbon dispersion medium, comprising the following steps of: (A) performing a primary dispersion in the absence of surfactants by adding an aqueous solution of a water-soluble ethylenically unsaturated monomer containing a hydrophilic polymeric dispersion agent to a petroleum hydrocarbon dispersion medium in which a hydrophobic polymeric dispersion agent was heat-dispersed or heat-dissolved, under stirring; (B) further performing a secondary dispersion by adding a surfactant to a dispersion liquid obtained after the primary dispersion; and (C) performing the reversed-phase suspension polymerization by using a radical polymerization initiator; and the water-absorbent resin obtained by the method.

Abstract: A process for making an aqueous dispersion of fluorinated ionomer particles by polymerizing in a first polymerization step at least one fluorinated monomer having an ionic group in an aqueous polymerization medium in the presence of initiator, the polymerizing providing dispersed particulate of fluorinated ionomer, polymerizing in a second polymerization step at least one fluorinated monomer having an ionic group in the aqueous polymerization medium in the presence of the dispersed particulate of fluorinated ionomer and initiator to form the aqueous dispersion of particles of fluorinated ionomer, and suspending the first polymerization step prior to beginning the second polymerization step.

Abstract: A process for making an aqueous dispersion of fluorinated ionomer particles by providing dispersed particulate of fluorinated ionomer in an aqueous polymerization medium and polymerizing at least one fluorinated monomer having an ionic group in the aqueous polymerization medium in the presence of the dispersed particulate of fluorinated ionomer and initiator to form the aqueous dispersion of particles of fluorinated ionomer.

Abstract: A process for producing high-quality polymer microparticles having uniform particle size of the order of several micrometers to tens of micrometers by inverse suspension polymerization at high productivity while keeping excellent dispersion stability without causing aggregation among particles. The inverse suspension polymerization involves a vinyl monomer and is performed in at least two steps. A water-soluble oxidizing agent and a water-soluble reducing agent are used as a polymerization initiator, and the water-soluble reducing agent is fed after the water-soluble oxidizing agent is fed.

Abstract: Process for preparing an aqueous polymer composition using water-soluble free radical chain regulators.

Abstract: The present invention relates to a process for the production of polyvinyl chloride (PVC) having a median grain size of from 10 to 80 ?m by suspension polymerization of vinyl chloride, the process comprising the following process steps: (a) introduction of water, initiator(s), optionally one or more further adjuvants, and some of the vinyl chloride into a container as initial charge and mixing of the constituents; (b) dispersion, and addition of one or more suspension auxiliaries with continued dispersion; (c) heating of the mixture; (d) addition of the remaining vinyl chloride; and (e) working-up of the product.

Abstract: A process for making an aqueous dispersion of fluoropolymer particles by providing dispersed particulate of fluorinated ionomer in an aqueous polymerization medium and polymerizing at least one fluorinated monomer in the aqueous polymerization medium in the presence of the dispersed particulate of fluorinated ionomer and initiator to form the aqueous dispersion of particles of fluoropolymer.

Abstract: Process for the preparation of finely divided aqueous polymer dispersions having a narrow particle size distribution.

Abstract: Disclosed are coating compositions that include a continuous phase that includes water and a dispersed phase that includes a microgel having a mean particle size of greater than 50 nanometers. The microgel is formed from reactants selected so as to provide a copolymer having a certain calculated Tg and includes a cycloaliphatic (meth)acrylate.

Abstract: The present invention relates to a process for the production of the largest possible spherical, monodisperse polyvinylpyrrolidone (PVP) seed particles in the micron range by dispersion polymerisation. The particles obtained in this way represent novel starting materials for the production of macroporous polymer particles, which can in turn be employed in preparative and analytical chromatography for protein preparation. They can also be employed as base material for further reactions. The novel process for the polymerisation of N-vinylpyrrolidone, which is inexpensive to carry out, gives particles having optimised quantities, such as monodispersity, sphericity and particle diameter, which can be employed in further reactions and have advantageous, in particular improved, properties for use in chromatographic separation methods.

Abstract: Aqueous suspension comprising 35-45 wt % of solid diacyl peroxide particles having a d50 in the range 1-10 microns, 0.05-1 wt % of a dispersant, and not more than 1 wt % of an organic solvent. This concentrated peroxide suspension comprises only a minor amount of dispersant, has a low volatile organic content and is nonetheless stable for months and low in viscosity.

Abstract: A process for making an aqueous dispersion of fluoropolymer particles by polymerizing in a first polymerization step at least one fluorinated monomer having an ionic group in an aqueous polymerization medium in the presence of initiator, the polymerizing providing dispersed particulate of fluorinated ionomer, and polymerizing in a second polymerization step at least one fluorinated monomer in the aqueous polymerization medium in the presence of the dispersed particulate of fluorinated ionomer and initiator to form the aqueous dispersion of particles of fluoropolymer.

Abstract: The present invention relates to a process for preparing microcapsules comprising a lipophilic capsule core and a capsule wall synthesized from 30% to 100% by weight, based on the total weight of the monomers, of one or more monomers (monomers I) from the group comprising C1-C24 alkyl esters of acrylic and/or methacrylic acid, acrylic acid, methacrylic acid, and maleic acid, 0% to 70% by weight, based on the total weight of the monomers, of one or more difunctional or polyfunctional monomers (monomers II) which are sparingly soluble or insoluble in water, and 0% to 40% by weight, based on the total weight of the monomers, of one or more other monomers (monomers III).

Abstract: The invention provides homogeneous compositions in solid form comprising a) from 50 to 90% by weight of polyvinyl acetate and b) from 10 to 50% by weight of vinyl acetate-vinyl laurate copolymer, the weight percentages based on the total weight of the composition.

Abstract: The invention relates to a process for the manufacture of a waterborne multistage polymer dispersion that has ethylenically unsaturated functional groups for crosslinking. The process comprises the steps of; a. making an aqueous emulsion or solution of a first stage polymer comprising carboxylic acid functionalized monomers to an amount sufficient to make the first stage polymer water soluble or dispersible, b. at least partially neutralizing the first stage polymer with a base, c. forming a two-stage polymer dispersion by adding to the at least partially neutralized first stage polymer a second stage monomer mixture and emulsion polymerizing said second stage monomer mixture to a second stage polymer which is less hydrophilic than the first stage polymer, d. reacting with the obtained two-stage polymer dispersion a bi-functional compound comprising an ethylenically unsaturated group and a group reactive towards the carboxylic acid in the two-stage polymer.

Abstract: A polymeric latex prepared by aqueous emulsion polymerization of a monomeric mixture comprising styrene and butadiene in the presence of a seed polymer prepared by aqueous emulsion polymerization of styrene and a salt of 2-acrylamido-2-methylpropanesulfonic acid.