Abstract: Melt processable copolymers of vinylidene fluoride and hexafluoropropylene, containing from about 1% to about 20% hexafluoropropylene by weight, are prepared by emulsion polymerization of vinylidene fluoride and hexafluoropropylene in a stirred aqueous reaction medium. The reaction medium is formed by charging to a heated reactor, water, vinylidene fluoride, an initiator to start the polymerization, and a water-soluble surfactant capable of emulsifying both the initiator and the reaction mass during polymerization. Additional amounts of vinylidene fluoride and initiator are fed to the reaction medium to continue polymerization of the vinylidene fluoride monomer until from about 50% to about 90% of the total weight of the vinylidene fluoride monomer utilized in the process has been added to the reaction medium.

Abstract: A vinyl chloride resin for safety glass, comprising either particles of a copolymer of a vinyl chloride monomer and an epoxy-containing monomer, having a particle diameter up to 5 .mu.m and a greater epoxy content in an outer portion than in a an inner portion of the particles, or agglomerates of the particles, and process for the preparation of this resin, comprising either adding an epoxy-containing monomer into a polymerization reaction mixture of a vinyl chloride monomer substantially during a latter half of the polymerization reaction of the polymerization mixture or adding an epoxy-containing monomer and a vinyl chloride monomer either in the form of a mixture solution or separately but at the same time into a polymerization mixture of the vinyl chloride monomer.

Abstract: A process for preparing copolymer beads suitable for conversion to ion exchange resins, comprising forming a polymeric matrix containing a plurality of free radicals, and continuously adding to said matrix, under conditions suitable for polymerizing a monomer feed which is imbibed by and polymerized within the matrices. Ion exchange resins prepared from beads made by such process exhibit improved osmotic and mechanical properties.

Abstract: Vinyl polymers, e.g., the homo- and copolyvinyl chlorides, are prepared in one or more stages, to a degree of conversion of at least 50%, by suspended emulsion polymerizing at least one vinyl monomer, e.g., vinyl chloride, said at least one monomer having dispersed therein finely divided droplets of an aqueous solution of at least one component of a polymerization initiating system, and wherein the amount of water in said aqueous solution constitutes at least 19%, and preferably at least 20% by weight of the at least one monomer.

Abstract: An improved wet strength binder is prepared by a process in which interaction between an olefinic carboxylic acid monomer, such as itaconic acid, and a cross-linker, such as MAGME, is minimized.

Abstract: The preparation of polymers free from emulsifiers and protective colloids by the free-radical initiated emulsion polymerization of ethylenically unsaturated copolymerizable monomers, wherein the emulsion polymerization is carried out in the absence of emulsifiers and protective colloids, using water-soluble, free-radical forming initiators and with the addition, at least at the start of the polymerization, of at least 0.01% by weight, based on the total amount of monomers, of poly-(ethylenically unsaturated) monomers, and the polymers can be obtained in the form of aqueous or non-aqueous dispersions or in the form of powder.The use of the polymers in the form of dispersions or powders for modifying polymer materials and polymer raw materials and for the production of shaped articles and films.

Abstract: A conjugated diene copolymer comprising (A) 40 to 90 mole % of a conjugated diene component, (B) 0.5 to 10 mole % of an alpha,beta-ethylenically unsaturated carboxylic acid component, (C) 0.1 to 5 mole % of a polyfunctional alkenyl compound component and (D) 5 to 58 mole % of a monoolefinically unsaturated compound component wherein the intrinsic viscosity [.eta.] of the copolymer as measured at 30.degree. C. in dimethylformamide is 0.01 to 3.0 dl/g, the width (.DELTA.Tg) of the endothermic transition temperature section determined by a differential scanning calorimetry is 45.degree. to 120.degree. C., and the limit temperature (T.sub.1) on the lower temperature side of the endothermic transition temperature section is -40.degree. C. or less.

Abstract: Copolymers comprising ethylene, alpha-olefin, and olefinic chlorosilane or olefinic hydrocarbon halide, and method of preparing copolymers. The copolymers may be in the form of statistical copolymers, or may be formed of first and second segments. The copolymers are useful in fiberglass and rubber compositions, and for forming graft and block polymers. The copolymers may be cross-linked to form nodular copolymers. The nodular copolymers are particularly useful as lube oil additives.

Abstract: Copolymers of .alpha.-methylstyrene and acrylonitrile having improved composition of uniformity are prepared by emulsion polymerizing a first monomer stream having a weight ratio of .alpha.-methylstyrene/acrylonitrile from about 75/25 to about 85/15 and thereafter polymerizing a second monomer feed stream comprising acrylonitrile.

Abstract: What is described herein is a solution feed, slurry precipitation polymerization process for making copolymers of maleic anhydride and an alkyl vinyl ether within a predetermined viscosity range.The process of the invention is characterized by precharging a large excess of the alkyl vinyl ether in a reactor, feeding maleic anhydride dissolved in a minimum amount of an organic solvent into the precharged reactor, and polymerizing the monomers in the presence of a free radical initiator. The copolymer product then appears as a pumpable slurry in the reaction medium. The slurry is discharged from the reactor and the desired copolymer is obtained therefrom as a fine, white powder having specific viscosities in the range of about 1.5-6.0, and preferably about 2.6-3.5.

Abstract: There are disclosed copolymers of aromatic vinyl compounds, e.g., styrene, and conjugated diolefins, e.g., butadiene, possessing a differential content of the aromatic vinyl compound such that in at least one of the end portions of the copolymer the differential content shows a sharp and substantial increase in the direction of the outer extremity of the end portion. Preferred compolymers are styrene-butadiene copolymers having a vinyl content of at least 30%. In special embodiments, the copolymer have a styrene content changing in a portion of no more than 5% of the copolymer chain from a first value to a second value, the second value being at least 25 percentage points greater than the first value, and the portion is present within a 10% terminal portion of the copolymer. The copolymers are useful in the tread portions of tires as tires containing such copolymers in the tread composition have improved rolling resistance and/or grip on wet road surfaces.

Abstract: A copolymer of vinylidene fluoride and trifluoroethylene having piezoelectric properties useful at elevated temperatures. The total molar content of trifluoroethylene is less than 30% characterized in that it has a heterogeneous structure with a distribution of accumulated molar composition comprised between two straight lines:Y=-3.18 X +140 andY=-3.12 X +109X is the molar percentage of trifluoroethylene in the macromolecular chains and Y is the percentage by weight of the total of macromolecular chains in which the content of trifluoroethylene is above or equal to X.

Abstract: A method of carrying out a continuous aqueous emulsion copolymerization using a single continuously stirred tank reactor to reduce the particle size distribution and the presence of over-sized particles comprises, slowly supplying to a reactor the materials used in the copolymerization, including the monomers which are copolymerized, while maintaining conditions causing copolymerization to proceed until the reactor is filled. The supply is continued while maintaining those conditions until the total supply is in the range of from about 1.5 to about 5 reactor volumes. The excess material in the reactor is removed therefrom and collected in one or more separate vessels, and the product of the copolymerization is then combined and mixed to form a uniform product. The composition copolymerized can be changed during the copolymerization. The emulsion copolymer product is particularly useful in latex paints where it improves the gloss and scrub resistance of the paint.

Abstract: A solution feed, solution polymerization method for making copolymers of maleic anhydride and an alkyl vinyl ether is described. In this process, maleic anhydride in a functional organic solvent is fed into a reactor precharged with an alkyl vinyl ether. The reactant solution is polymerized in the presence of a free radical initiator to provide copolymers in solution having low viscosities and high solids content.

Abstract: A process for producing monodispersed fine particles of a vinyl polymer is disclosed, which comprises polymerizing monomers containing at least one vinyl monomer selected from the group consisting of aromatic vinyl compounds, acrylic esters, and a methacrylic ester in the presence of (1) a surface active agent represented by formula (I) ##STR1## wherein R.sub.1 and R.sub.2, which may be the same or different, each represents a substituted or unsubstituted alkyl group having from 4 to 8 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted cyclohexyl group and M represents an alkali metal, (2) from 10.sup.-3 to 10.sup.-1 mol/l of a persulfate as a polymerization initiator, and (3) from 10.sup.-4 to 10.sup.-2 mol/l of a divalent metal sulfate as an electrolyte. Monodispersed vinyl polymer fine particles having a particle size of 1 .mu.m or greater with a very narrow size distribution are obtained.

Abstract: A conjugated diene copolymer comprising (A) 40 to 90 mole % of a conjugated diene component, (B) 0.5 to 10 mole % of an alpha,beta-ethylenically unsaturated carboxylic acid component, (C) 0.1 to 5 mole % of a polyfunctional alkenyl compound component and (D) 5 to 58 mole % of a monoolefinically unsaturated compound component wherein the intrinsic viscosity [.eta.] of the copolymer as measured at 30.degree. C. in dimethylformamide is 0.01 to 3.0 dl/g, the width (.DELTA.Tg) of the endothermic transition temperature section determined by a differential scanning calorimetry is 45.degree. to 120.degree. C. and the limit temperature (T.sub.1) on the lower temperature side of the endothermic transition temperature section is -40.degree. C. or less.

Abstract: The invention concerns copolymers of propylene and but-1-ene in which the proportion of units derived from but-1-ene is from 10 to 40% by weight and the proportion of isolated ethyl branches which they contain is at least equal to the square of the proportion [P] of units derived from propylene contained in said copolymers. The copolymers of the invention can be used for the production of heat-sealable films.

Abstract: Novel copolymers of ethylene containing per 100 parts by weight ethylene 0.2 to 5.0 parts by weight of 2,4,4-trimethylpentene-(1) and optionally 2.0 to 20 parts by weight of vinyl ester or vinyl ether or ester of acrylic acid or methacrylic acid with alcohols of 1 to 8 carbon atoms having a melt index MFI (190/2.16) of 0.4 to 20 g/10 min. a density of 0.915 to 0.960 g/ml and an impact tensile strength of 850 to 2,600 mJ/mm.sup.2 and a process for their preparation useful for making transparent films.

Abstract: Cast ceiling tile requires a particular rheology of its wet formulation for the dried tile to have a desired aesthetic appearance. The use of a latex binder rather than starch for cast ceiling tiles imparts the necessary rheological properties to the wet ceiling tile formulation. The tile is prepared by blending mineral wool with a premixture of water, latex, and filler, said premixture having a sharp yield point when measured with a recording Brookfield Viscometer. The latex is an alkali-swellable latex comprising (i) a C.sub.3 -C.sub.8 .alpha.,.beta.

Abstract: An improved emulsion polymerization process for the preparation of high Mooney viscosity terpolymers of ethylene, vinyl acetate, and reactive halogen-containing monomers is provided. In the process, the reactive halogen-containing monomer is added during the polymerization. The ethylene pressure may also be increased during the polymerization.

Abstract: Styrene or other anionically polymerizable monomer is anionically homopolymerized in a dispersion using a non-solvent, e.g., hexane using three or more stages to obtain spherical microparticles, e.g., 2-5 microns, with a narrow size distribution.

Abstract: Copolymers of ethylene with vinyl esters are prepared in a continuously operated tubular polymerization system at high pressure and temperatures by feeding a mixture of ethylene, vinyl ester, initiator and, if appropriate, regulant into the polymerization system in the form of a mainstream at the inlet point thereof and at the same time through two or more secondary streams downstream of the inlet point, secondary streams (I) being metered in at points where the reaction temperature has just exceeded a maximum temperature due to the heat of polymerization and secondary streams (II) at points which, relative to the direction of flow of the ethylene, are upstream of the feed points of secondary streams (I) and upstream of the respective maximum temperature.

Abstract: Copolymers of ethylene with acrylates or solutions of free acrylic acid in acrylates are prepared in a continuously operated tubular polymerization system at high pressures and temperatures by feeding a mixture of ethylene, acrylate, initiator and, if appropriate, regulant into the polymerization system in the form of a main stream at the inlet point thereof and at the same time through two or more secondary streams, secondary streams (I) being metered in at points where the reaction temperature has just exceeded a maximum temperature due to the heat of polymerization and secondary streams (II) at points which, relative to the direction of flow of the ethylene, are upstream of the feed points of secondary streams (I) and upstream of the respective maximum temperature.

Abstract: This invention provides an improvement in anionic polymerization processes which comprise both a batch polymerization step to form and partially grow living polymer chains and a subsequent continuous or semi-continuous step in which growth of the chains is continued. For purposes of this improvement, the transition to the continuous or semi-continuous step takes place before the molar concentration of monomer in the batch polymerization step is depleted to a level below that of the living chains. Anionic polymerization processes are recognized as particularly useful for the production of polymers having narrow molecular weight distributions. Practice under the invention is found to enhance the narrow distribution of the polymer product by controlling thermal die-out of chains which has occurred in conventional processes during the transition from batch to continuous or semi-continuous polymerization steps.

Abstract: In a copolymerization process of propylene, a mixture of unreacted propylene and ethylene is recovered. It is then fed to a distillation system which includes first and second distillation columns. The distillation system is operated in such a way that the temperature and pressure of the top of the second distillation column remain constant and an ethylene-propylene mixture can be recovered at a constant ethylene/propylene ratio from the top of the second distillation column. By using the thus-recovered ethylene-propylene mixture, the copolymerization reaction can be carried out under excellent control so that the ethylene-propylene copolymer can be obtained with uniform quality and properties.

Abstract: An ultra-high molecular weight polyethylene powder easily soluble in organic solvents and suitable for use in the preparation of fibers or films having a high strength and a high elastic modulus, said polyethylene powder having an intrinsic viscosity in the range of 5 to 30 dl/g in decalin at 135.degree. C. and being obtained by at least two-step polymerization reactions which are:a first step of polymerizing ethylene in the absence of hydrogen or at a reduced hydrogen concentration, using a catalyst containing a solid catalyst component and an organometallic compound, said solid catalyst component containing at least magnesium and titanium and/or vanadium, to produce 50-99.5 parts by weight, based on 100 parts by weight of a final polyethylene product, of polyethylene having an intrinsic viscosity of 12 to 32 dl/g in decalin at 135.degree. C.; anda second step of polymerizing ethylene at a higher hydrogen concentration that in said first step to produce 50-0.5 parts by weight of polyethylene.

Abstract: Copolymers which contain, as copolymerized monomer units, monoethylenically unsaturated mono- and dicarboxylic acids are prepared by a process in which(a) from 10 to 60% by weight of a monoethylenically unsaturated dicarboxylic acid of 4 to 6 carbon atoms, its salt and/or, if appropriate, its anhydride,(b) from 90 to 40% by weight of a monothylenically unsaturated monocarboxylic acid of 3 to 10 carbon atoms and/or its salt and(c) from 0 to 20% by weight of another, carboxyl-free monoethylenically unsaturated monomer which is copolymerizable with (a) and (b),the percentages being based on the sum of the monomers, are polymerized in the presence of from 0.5 to 5% by weight of a water-soluble free-radical-forming initiator in an aqueous medium at from 60.degree. to 150.degree. C.

Abstract: A method for producing by suspension polymerization a copolymer comprising a vinyl cyanide compound and an aromatic vinyl compound having excellent transparency, and uniform composition, and a content of the polymerized residue of vinyl cyanide compound in the range of from 50 to 85% by weight comprising the steps of: (a) carrying out initial charging of the total quantity of the vinyl cyanide compound and a partial quantity of the aromatic vinyl compound at a compositional ratio, wherein the content of the vinyl cyanide compound in the resulting copolymer attains an intended ratio within a range of from 50 to 85% by weight; (b) initiating the copolymerization reaction by adding a polymerization initiator having a decomposition half-life at 95.degree. C.

Abstract: A new class of hydrocarbon foaming agents which are block copolymers, one block of which is a styrene derivative, the other a vinylsilane derivative. Said hydrocarbon foaming agents are nonreactive with common anionic initiators.

Abstract: Process of polymerizing a monomer charge including ethylene by (1) drying an inorganic oxide having surface hydroxyl groups to form a support that is substantially free of adsorbed water, (2) reacting the surface hydroxyl groups of the support with at least about 0.5 mol, per mol of surface hydroxyl groups, of at least one organometallic compound corresponding to the formula R.sub.x MR'.sub.y R".sub.z, wherein M is a metal of Group III of the periodic table, R is an alkyl group containing 1 to 12 carbon atoms, R' and R" are independently selected from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z both represent values of 0 to 2, the sum of which is not greater than 3-x, (3) reacting the thus-treated support with at least about 0.001 molar proportion, per mol of organometallic compound, of a vanadium component consisting essentially of a mixture of about 10-90 mol percent of VOCl.sub.

Abstract: Process of polymerizing a monomer charge including ethylene by (1) drying an inorganic oxide having surface hydroxyl groups to form a support that is substantially free of adsorbed water, (2) reacting the surface hydroxyl groups of the support with at least a substantially stoichiometric amount of at least one organometallic compound corresponding to the formula R.sub.x MR'.sub.y R".sub.z, wherein M is a metal of Group III of the periodic table, R is an alkyl group containing 1 to 12 carbon atoms, R' and R" are independently selected from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z both represent values of 0 to 2, the sum of which is not greater than 3-x, (3) reacting the thus-treated support with at least about 0.001 mol, per mol of organometallic compound, of at least one vanadium compound corresponding to a formula selected from (RO).sub.n VOX.sub.3-n and (RO).sub.m VX.sub.4-m, in which formulas R represents a C.sub.1 -C.

Abstract: In a gas-phase fluidized-bed polyethylene reactor using a Ziegler catalyst under operating conditions, a co-catalyst, such as triethyl aluminum, is added to the reactor by mixing the TEA with some of the feed ethylene and pumping the solution into the reactor.

Abstract: The preparation of polymers free from emulsifiers and protective colloids by the free-radical initiated emulsion polymerization of ethylenically unsaturated co-polymerizable monomers, wherein the emulsion polymerization is carried out in the absence of emulsifiers and protective colloids, using water-soluble, free-radical forming initiators and with the addition, at least at the start of the polymerization, of at least 0.01% by weight, based on the total amount of monomers, of poly-(ethylenically unsaturated) monomers, and the polymers can be obtained in the form of aqueous or non-aqueous dispersions or in the form of powder.The use of the polymers in the form of dispersions or powders for modifying polymer materials and polymer raw materials and for the production of shaped articles and films.

Abstract: Process of polymerizing a monomer charge including ethylene by (1) drying an inorganic oxide having surface hydroxyl groups, e.g. silica, alumina, magnesia, etc. to remove adsorbed water (2) reacting the surface hydroxyl groups with at least a stoichiometric amount of an organometallic compound having at least one alkyl group attached to a Group III metal, e.g., a trialkylaluminum, (3) reacting the thus-treated inorganic oxide with a vanadium halide, such as (a) VOCl.sub.3, VOBr.sub.3, and/or mono-, di-, and/or trihydrocarbyloxy derivatives thereof and/or (b) VCl.sub.4, VBr.sub.4, and/or mono-, di-, tri-, and/or tetrahydrocarbyloxy derivatives thereof, (4) reacting that reaction product with at least about 0.1 mol, per mol of organometallic compound, of an ether-alcohol corresponding to the formula R"[OCHR'(CH.sub.2).sub.n CHR].sub.

Abstract: Process of polymerizing a monomer charge including ethylene by (1) drying an inorganic oxide having surface hydroxyl groups to form a support that is substantially free of adsorbed water, (2) reacting the surface hydroxyl groups of the support with at least a substantially stoichiometric amount of at least one organometallic compound corresponding to the formula R.sub.x MR'.sub.y R".sub.z, wherein M is a metal of Group III of the periodic table, R is an alkyl group containing 1 to 12 carbon atoms, R' and R" are independently selected from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z both represent values of 0 to 2, the sum of which is not greater than 3-x, (3) reacting the thus-treated support with at least about 0.001 mol, per mol of organometallic compound, of at least one vanadium compound prepared by reacting one molar proportion of VOCl.sub.3 and/or VOBr.sub.3 with about 0.

Abstract: A heat-resistant copolymer obtained by copolymerizing (A) 72-82 parts by weight of .alpha.-methylstyrene and (B) 26-18 parts by weight of acrylonitrile, characterized in that the copolymer contains (a) 0-15% by weight of monomer chain --(A)--(A)--(A)--, (b) 50% by weight or more of monomer chain --(A)--(A)--(B)--, and (c) 50% by weight or less of monomer chain--(B)--(A)--(B)--, the total of (a), (b) and (c) being 100% by weight. This copolymer is excellent in heat stability and moldability when molded at high temperatures, and the blending of this copolymer with other thermoplastic resins gives thermoplastic resins with excellent heat resistance.

Abstract: An improved process for continuously producing ethylene-vinyl acetate copolymer containing 20 to 50 mole % of ethylene is provided. An aliphatic alcohol solvent is employed in the polymerization vessel. Ethylene vapor discharged from the polymerization vessel is introduced into the tubes of the lower part of a multi-tubular heat exchanger. Vinyl acetate is introduced into the upper part of the heat exchanger and caused to flow through said tubes, thereby effecting absorption and solubilization of ethylene into the vinyl acetate. The solubilized ethylene and vinyl acetate is passed to the polymerization vessel. The process of this invention permits the stable production of the copolymer over a long period of time.

Abstract: Disclosed is a process for producing copolymers of ethylene and vinyl acetate in a continuous stirred-tank reactor in which the ethylene and vinyl acetate are premixed and the reactor is continuously purged.

Abstract: Terpolymers comprising propylene and small amounts of ethylene and butene-1 are made in a two-stage process wherein a relatively high melting random terpolymer is made in a first stage and a relatively low-melting random terpolymer incorporating a higher concentration of ethylene, is made in a second stage so that it is dispersed in the product of the first stage. The two process stages may be operated in a single batch reactor or two continuous reactors in series.

Abstract: An emulsion polymer of a water insoluble vinylic monomer and an acrylic monomer is formed by precharging a portion of the acrylic monomer and thereafter adding a comonomer charge corresponding to the final desired composition of the vinylic monomer and acrylic monomer at an addition rate generally corresponding to the steady state monomers concentration. A high non-volatiles content is maintained to inhibit the acrylic monomer from partitioning into the aqueous phase.

Abstract: Copolymers of ethylene containing not more than 4 moles, based on 100 moles of ethylene, of copolymerized C.sub.3 -C.sub.6 -alkenecarboxylic acids are prepared in a continuously operated tubular polymerization system under high pressures and temperatures in the presence of a polymerization initiator by a process in which a mixture of ethylene, the alkenecarboxylic acid, if required a further monomer which is copolymerizable with ethylene, an initiator and, if required, a regulator is fed into the polymerization system at its entrance and at the same time at a second point downstream of the entrance, along the polymerization system, where the reaction temperature has exceeded a maximum, the amount of alkenecarboxylic acid at the entrance of the polymerization system being not more than 0.3, preferably less than 0.28, mole, based on 100 moles of ethylene, and the remainder being metered in at the second feed point.

Abstract: Pressure-sensitive adhesives are formed of a diester of fumaric acid, preferably dibutyl fumarate; an alkyl acrylate, preferably 2-ethylhexylacrylate; an alkyl methacrylate, preferably methylmethacrylate; and, desirably, a crosslinkable carboxylic acid. The adhesives are preferably formed in two-stage, free-radical polymerization.

Abstract: The invention provides a process for the preparation of polymer latex by emulsification of an initiator or initiator mixture and optionally a solvent in the presence of emulsifier in water in a first step and adding a monomer and polymerizing in a second step. The process is carried out by emulsifying an essentially water-insoluble initiator or initiator mixture in the first step at a temperature above the melting point of the initiator or initiator mixture if no solvent is used, and below its decomposition temperature, optionally together with an essentially water-insoluble liquid solvent, which forms a liquid solution together with the initiator or the initiator mixture at the emulsification temperature, then, in a second step adding monomer, possibly additional emulsifier and that part of the desired amount of water which was not added in the first step, and initiating polymerization as per se known by heating.

Abstract: Water-dispersible polymers of an acid salt of 2-aminoalkyl esters of monounsaturated monocarboxylic acid and at least one comonomer are prepared by dissolving the salt of that ester in a coupling solvent, mixing the comonomers as a separate feedstock and bringing the monomers together in a polymerization zone at a controlled rate so that the monomers remain in solution and polymerizing to substantial completion.

Abstract: Process for preparing aqueous dispersions of a somewhat water-soluble low-molecular organic material, in which swellable particles prepared in a first step are swelled with the organic material in the second step. When the organic material is a polymerizable monomer the dispersion prepared is converted to a polymer dispersion. In the first step swellable oligomer or oligomer-polymer particles are prepared by(a) dispersing an aqueous mixture containing an oil-soluble initiator or a solution of an oil soluble initiator in an organic solvent, and then swelling the dispersed initiator-containing droplets with monomer and effecting polymerization, or(b) swelling polymer particles in aqueous dispersion with vinyl monomer and an oil-soluble initiator and effecting polymerization, the ratio between initiator and monomer used being so high that in the polymerization an oligomer having a degree of polymerization of 5-200 is formed.

Abstract: A modacrylic fiber comprising a copolymer containing acrylonitrile, at least one of vinyl chloride and vinylidene chloride, and a sulfo group-containing vinyl monomer having a relative reactivity of at least 1 to acrylonitrile, in a specific ratio. The copolymer is prepared by polymerizing the monomers, while adding the sulfo group-containing vinyl monomer to the polymerization system under the following condition:16<Y-X<83wherein X and Y are percentages of the amount of a polymer produced at the time of starting the addition and the amount of a polymer produced at the time of finishing the addition, respectively, based on the amount of the whole polymer to be produced. The fiber has an excellent flame resistance and an excellent devitrification preventing property.

Abstract: A process for the suspension copolymerization of vinyl chloride and chlorotrifluoroethylene to form a copolymer having a constant weight ratio of vinyl chloride and chlorotrifluoroethylene independent of conversion, which consists in polymerization with an initial charge containing excess vinyl chloride and adding additional vinyl chloride prior to reaching the conversion where the copolymer composition changes.

Abstract: An acrylonitrile polymer comprising acrylonitrile, at least one of vinyl chloride and vinylidene chloride, a sulfo group-containing vinyl monomer having a higher reactivity ratio than acrylonitrile and a methallyl sulfonic acid monomer, which is prepared by conducting a polymerization in a manner such that at least half amount of the methallyl sulfonic acid monomer to be used is added to the polymerization system in a substantial period of adding the sulfo group-containing vinyl monomer having a higher reactivity ratio than acrylonitrile to the system. The acrylonitrile polymer is suitable for the preparation of a modacrylic synthetic fiber, and the modacrylic fiber prepared therefrom has excellent flame resistance, devitrification preventing property and dyeing affinity.

Abstract: Disclosed is an improvement in the (co)polymerization of an isocyanate-containing monomer, e.g., an isocyanatoalkyl methacrylate, forming a product of very low residual toxic monomeric isocyanate (less than 500 ppm) useful in avoiding air pollution. The improvement consists in adding a scavenger, a small amount of an active nonpolluting monomer such as butyl acrylate, near the end of the polymerization.

Abstract: A process for the preparation of emulsion polymers having a solid content of about 65% to about 80% is disclosed. The process comprises the step of adding a monomeric mixture to a reaction system maintained at a temperature of from about 60.degree. C. to about 90.degree. C., the monomer addition not exceeding an hourly rate of about one-fourth of the total monomer to be added, the mixture comprising monomers having a particle size of from about 10-100 microns, the system having therein an emulsifier and initiator at the time of the monomeric addition.