Abstract: A polybutadiene latex is prepared by a process in which butadiene is polymerized by free radical emulsion polymerization in the presence of initiator and, if required, dispersants and further conventional assistants, the polymerization being carried out in the presence of reactive comonomers in such a way that the heat flow of 43 watt/kg solids content of the polymerization mixture is not exceeded. Owing to the presence of reactive comonomers, the reaction rate at the beginning of the reaction is increased, with the result that an overall flatter heat flow profile is obtained. A preferred reactive comonomer is styrene.

Abstract: The present invention relates to a method of preparing rubber-modified styrene copolymer resin with excellent transparency and impact resistance, specifically to a method of preparing transparent resin of rubber-modified styrene copolymer comprising graft-copolymerizing styrene monomer and (meth)acrylate monomer in the presence of block or random styrene-butadiene copolymer which has 30-50% of styrene skeleton content and 20-40 cp of 5% toluene solution viscosity at 25 iÉ. According to the method of the present invention, the transparent resin containing the rubber particles of a double structure comprising onion and core-shell structure can provide transparent resin of rubber-modified styrene copolymer resin with excellent transparency and impact resistance as well as good gloss.

Abstract: The graft copolymer made from a1: from 10 to 90% by weight of a particulate graft base A1, made from a particulate emulsion polymer with a glass transition temperature below 0° C.

Abstract: An aromatic vinyl-conjugated diene block copolymer rubber comprising 50 to 75% by weight of conjugated diene monomer units and 25 to 50% by weight of aromatic vinyl monomer units, wherein the content of vinyl bond in the conjugated diene monomer units is at least 50% by weight, the ratio of blocked aromatic vinyl in the aromatic vinyl monomer units is at least 70% and the number average molecular weight of the copolymer rubber is in the range of 280,000 to 1,000,000. An aromatic vinyl resin having incorporated therein the aromatic vinyl-conjugated dione block copolymer rubber gives a shaped article having good impact resistance and luster, and characterized in that the luster is thermally stable and the luster varies only to a minimized extent within the shaped article.

Abstract: Thermoplastic molding materials containing the following ingredients with regard to components A-F: A) 5-70 wt. % of at least one graft copolymer A) consisting of a rubber elastic base with a glass transition temperature below 0° and a grafted overlay made of a styrene compound and acrylonitrile or methacrylonitrile or mixture thereof in addition to, optionally, other monoethylenically unsaturated monomers, B) 29-90 wt. % of a hard copolymer made of at least one styrene compound, acrylonitrile or methacrylonitrile or mixtures thereof and, optionally, other monoethylenically unsaturated monomers, C) 0-5 wt. % of at least one three-block copolymer X-Y-X with a middle block Y propylenoxide units and terminal block X made of ethyleneoxide units, D) 0.01-5 wt. % of at least one butylated reaction product of cresol with dicyclopentadiene, E) 0.01-5 wt. % of at least one thiocarboxylic acid ester, F) 0.01-5 wt.

Abstract: Disclosed are a conjugated diolefin (co)polymer rubber formed from either a conjugated diolefin or a conjugated diolefin and an aromatic vinyl compound, wherein the (co) polymer rubber has a primary amino group and an alkoxysilyl group which are bonded to a (co)polymer chain; a process for producing the same; a rubber composition; a composite; and a tire. The (co) polymer rubber has satisfactory processability, and can give an automotive tire tread having a balance among wear resistance, failure characteristics, low hysteresis loss and wet-skid characteristics.

Abstract: The present invention relates to a method for preparing a copolymer containing a combined linear and nonlinear block, that is, mikto block, a copolymer prepared from the method, and usages of the copolymer. More particularly, the present invention provides a novel method for preparing a multi-component copolymer by polymerization using a multifunctional compound and one charge of an initiator, and a copolymer having a mikto block including different types of terminal blocks.

Abstract: It has been discovered that improved polystyrene products may be obtained by polymerizing styrene in the presence of at least one multifunctional initiator, at least one chain transfer agent, and at least one cross-linking agent. The presence of the multifunctional initiator tends to cause more branched structures in the polystyrene. A mathematical model that helps optimize the levels of these additives for given molecular weights, melt flow indices (MFIs) and zero shear viscosities (&eegr;0) has also been discovered.

Abstract: The invention relates to an anionically polymerised, impact-resistant polystyrene with a dispersed plasticiser phase, comprising particles with capsule particle morphology and method for production thereof.

Abstract: Compositions comprising hydrogenated block copolymers can be successfully used in a variety of applications including films, profiles, sheets, pultruded articles, fibers, coated articles, injection molded articles and blow or rotational molded articles.

Abstract: Thermoplastic molding composition characterized in that the polymer proportion soluble in dichloromethane has a c50 value of acrylonitrile of ≧28 wt. % and a chemical distribution (c90−c10 value) of the acrylonitrile of ≧5 wt. % is disclosed. The composition is characterized by its improved processability by extrusion and thermoforming.

Abstract: The invention relates to homopolymers and/or copolymers containing <100 ppm coarse particles with a particle diameter of between 200 and 500 &mgr;m, to thermoplastic moulding materials containing said homopolymtrs and/or copolymers, to the use of the homopolymers and/or copolymers and moulding materials for the production of moulded parts and to the moulded parts themselves.

Abstract: An emulsion polymerization process for the preparation of polybutadiene grafted with styrene and acrylonitrile monomers in a reaction system is provided. The resultant product has a low end content of unreacted residual monomers, low yellowness index, and improved impact strength. The diene rubber is prepared via a process wherein a chain transfer agent is added on a continuous basis to give a rubber substrate having a low crosslink density. In one embodiment of the invention, the process includes charging the reaction system with a pre-selected diene emulsion with a low crosslink density, adding a first portion of at least one of a styrene monomer and acrylonitrile monomer to the diene emulsion, adding to the reaction system, over a predetermined time, an initiator and a second portion of acrylonitrile and styrene monomer, and polymerizing the catalyzed reaction mixture of diene substrate, styrene and acrylonitrile to form ABS graft polymers.

Abstract: A method of producing a polymer or a stellar polymer which comprises polymerizing a vinyl monomer in the manner of living radical polymerization and adding a compound having two or more polymerizable carbon-carbon double bonds at the end point of the polymerization.

Abstract: A radial end-modified styrene-conjugated diene block copolymer having a general formula 1. The copolymer is obtained by synthesizing a styrene-conjugated diene block copolymer by way of copolymerization using an organic lithium initiator in the presence of a nonpolar solvent and then coupling the anionic active end of the resulting copolymer with a polyfunctional polysiloxane: (PS-PD)3Si—CH2CH2—[SiO(CH3)2—]nSi(CH3)2R  Formula 1 wherein, PS is polystyrene, PD is polydiene such as polyisoprene or polyisoprene-polybutadiene, R is hydroxy group or -(PD-PS), and n is an integer of 1 to 100. The block copolymer based adhesives have low melt viscosity and excellent adhesive strength.

Abstract: The graft copolymer (G) of the present invention is a graft copolymer which is prepared by emulsion graft polymerization of a rubber polymer comprising 0-50% by weight of a butadiene unit and 50-100% by weight of a (meth)acrylate unit and at least one monomer selected from aromatic alkenyl compound, methacrylate, acrylate and vinyl cyanide compound, said graft copolymer containing 0.5-2.0% by weight of an emulsifier residue. The thermoplastic resin composition containing the graft copolymer of the present invention causes less gas evolution during the molding, provides a molded article with good gloss of molding, and has excellent weather resistance, impact resistance and fluidity.

Abstract: A core-shell particle for use as filler in rubber compositions. In one embodiment, the particle comprises a crosslinked core having repeat aromatic vinyl units. During an emulsion polymerization, a crosslinked shell comprising of conjugated diene units is grafted onto the core through residual vinyl units. The polymeric shell provides for better interaction and dispersion of the styrene core in an otherwise immiscible polymer matrix, particularly diene-based polymers. In another embodiment, the core has repeat units of (i) about 0% to about 25% by weight of a conjugated diene unit, (ii) about 70% to about 85% by weight of an aromatic vinyl unit, and (iii) about 15% to about 30% by weight of a crosslinking monomer unit.

Abstract: A thermoplastic molding composition that features a combination of good notched impact strength and thermoplastic processability is disclosed. The composition contains one or more thermoplastic (co)polymers, a graft polymer and a combination of at least 3 components chosen from a compound (I) having at least one structural unit conforming to where M=a metal, and n=the valence of the metal M, and a compound (II) having at least one structural unit conforming to and a compound (III) having at least one structural unit conforming to and a compound (IV) that contains none of the structural units of (I), (II) and (III).

Abstract: It has been discovered that certain compounds serve as polymerization accelerators when employed together with peroxide initiators for the polymerization of vinylaromatic monomers. Suitable accelerators that increase the rate of decomposition of the peroxide initiator include, but are not necessarily limited to, hydroperoxides and/or metallic salts. Representative examples of suitable hydroperoxide accelerators include t-butyl hydroperoxide (TBH), cumyl hydroperoxide, and p-isopropyl cumyl hydroperoxide, whereas suitable metallic salt accelerators include cobalt naphthenate and cobalt acetoacetonate. Use of these accelerators when vinylaromatic monomers are polymerized in the presence of polybutadienes and peroxide initiators results in an increase in grafting as compared with similar copolymers made without the accelerator.

Abstract: A process for forming a copolymer comprising the steps of (i) preparing a living polymer segment by using anionic polymerization techniques, (ii) modifying the living polymer by reacting it with an alkyl metal halide to form an organometallic polymeric intermediate, and (iii) preparing a second polymer segment from the organometallic polymeric intermediate by combining the intermediate, conjugated diene monomer, and a coordination catalyst that will polymerize the conjugated diene monomer.

Abstract: A stretch material comprises a thermoplastic polymer material that meets the following conditions:

Abstract: The present invention relates to a method of acrylonitrile-butadiene-styrene (ABS) rubber latex, and the acrylonitrile-butadiene-styrene (ABS) latex is prepared by graft-polymerizing butadiene rubber with the monomers of acrlylonitrile and styrene through emulsion-polymerization, so that the ABS rubber latex of the present invention has high solid content. The method of ABS rubber latex of the present invention comprises the step of emulsion-polymerizing i) polybutadiene rubber latex; ii) aromatic vinyl compound; and iii) vinyl cyanide with the addition of a reactive emulsifier. According to the method of the present invention, the ABS rubber latex has high solid content due to a decrease in the amount of coagulated materials and film, which formed on the rubber latex during polymerization, and an increase in the production volume.

Abstract: The present invention provides highly branched block copolymers comprising branched soft segments with a low glass-transition temperature (Tg) and hard segments with a high Tg or crystalline melting point that exhibit thermoplastic elastomeric properties. More particularly the invention provides a highly branched block copolymer of a polyisoolefin and a polymonovinylidene arene characterized by having thermoplastic elastomeric properties wherein the aforesaid block copolymer comprises a highly branched polyisoolefin block and some of the branches of the aforesaid polyisoolefin block terminate in polymonovinylidene arene endblocks.

Abstract: Disclosed is a process for coupling styrenic block copolymers comprising admixing vinyl cyclohexene dioxide with a living block copolymer comprising at least one block of polymerized vinyl aromatic hydrocarbon monomers and at least one block of polymerized conjugated diene monomers, at a molar ratio of from 0.40 to 0.60 and carrying out a coupling reaction at a temperature of at least 65° C. to produce a coupled styrenic block copolymer. Also disclosed is a polymer composition comprising at most 30% by weight of a styrenic block copolymer comprising at least one block A of polymerized vinyl aromatic monomer(s) and at least one block B of polymerized conjugated diene(s) and at least 70% by weight of the styrenic block copolymer coupled with vinyl cyclohexene dioxide.

Abstract: The present invention provides high mechanical strength amphiphilic polymeric networks and implantable biological devices made therefrom that are capable of encasing and, thus, immunoisolating biological material from an immunological response of a host individual. The present invention also provides methods for making the amphiphilic networks and implantable biological devices. The present invention also provides a method for the treatment of type I diabetes mellitus comprising the steps of encasing a sufficient amount of islet of Langerhans cells within said biological device, wherein said biological device is capable of immunoisolating said encased islet cells upon implantation into an individual; implanting said biological device into a diabetic host individual; allowing said implanted biological device to remain implanted in said diabetic individual for a time sufficient to normalize the blood glucose level in said diabetic individual.

Abstract: A method of producing a stellar polymer which comprises polymerizing a vinyl monomer in the manner of living radical polymerization and adding a compound having two or more polymerizable carbon-carbon double bonds at the end point of the polymerization is provided. A composition which comprises, as an essential component, a hydroxyl-terminated polymer falling under said polymer and a compound having, in each molecule, not less than two functional groups reactive with the hydroxyl group is provided.

Abstract: A molding composition containing a graft polymer is disclosed. The graft is a product of a free-radical emulsion polymerization of resin-forming vinyl monomers in the presence of rubber present in latex form having a glass transition temperature of ≦0° C. using an initiator combination comprising a persulfate compound and a redox initiator system. The process for preparing the graft polymer entails adding the persulfate compound at the beginning of the graft polymerization reaction and a later addition of the redox initiator. The composition that features good gloss and flowability is suitable for the preparation of molded articles.

Abstract: This invention relates to polymer blends, which comprise at least one tapered conjugated diene-monovinylarene block copolymer and at least one styrenic polymer. The polymer blends possess good optical and mechanical properties.

Abstract: It has been discovered that sequential polyperoxides can be beneficially used as initiators for vinylaromatic/diene copolymers to give high grafting values and reasonable molecular weights. A new cyclic diperoxide did not give these same results. The sequential polyperoxide initiators can be used as the only initiators or together with other conventional peroxide initiators to advantage. The polymerization rate can also be increased using these sequential polyperoxide initiators.

Abstract: The present invention relates to selectively hydrogenated block copolymers where one of the blocks is a random copolymer of a mono-alkenyl arene monomer, such as styrene, and a 1,3-cyclodiene monomer, such as 1,3-cyclohexadiene, and one of the other blocks is a hydrogenated polymer or copolymer of an acyclic conjugated diene, such as 1,3-butadiene or isoprene.

Abstract: In a process for the anionic polymerization of vinylaromatic monomers or dienes in the presence of a lithium organyl or lithium alcoholate and a magnesium and/or an aluminum compound, a sterically hindered phenol or amine is added.

Abstract: A golf ball intermediate layer consists essentially of a specified triblock copolymer or its hydrogenation product, a specified block copolymer, or mixtures of these. The layer unexpectedly provides for improved ball performance with respect to spin rate, feel, and durability, without the expected disadvantages of use of such a layer. The layer can be incorporated into a wide variety of known ball constructions.

Abstract: Disclosed is a process for coupling styrenic block copolymers comprising admixing vinyl cyclohexene dioxide with a living block copolymer comprising at least one block of polymerized vinyl aromatic hydrocarbon monomers and at least one block of polymerized conjugated diene monomers, at a molar ratio of from 0.40 to 0.60 and carrying out a coupling reaction at a temperature of at least 65° C. to produce a coupled styrenic block copolymer. Also disclosed is a polymer composition comprising at most 30% by weight of a styrenic block copolymer comprising at least one block A of polymerized vinyl aromatic monomer(s) and at least one block B of polymerized conjugated diene(s) and at least 70% by weight of the styrenic block copolymer coupled with vinyl cyclohexene dioxide.

Abstract: An additive mixture containing a dibenzoate and either or both of a compound containing at least one structural unit and a compound containing at least one structural unit is disclosed. The additive combination enhances the processability of a thermoplastic molding composition that contains a (co)polymer of styrene, methyl methacrylate, acrylonitrile, methacrylonitrile, maleic anhydride and N-substituted maleimide and a graft copolymer.

Abstract: The present invention discloses a composition of matter consisting of a high impact polystyrene exhibiting improved environmental stress crack resistance. The HIPS material is formed utilizing polybutadiene, polyisoprene, and copolymers thereof with styrene, having a Mooney viscosity exceeding about 35 and a gel content of up to about 28%. The present invention discloses the use of a combination of lubricant additives to obtain a HIPS material with higher ESCR values than either additive alone could provide, and also discloses the optimum level of each additive.

Abstract: The present invention relates to a thermoplastic resin composition comprising a rubber-reinforced thermoplastic resin as component (A) and an ethylene-&agr;-olefin copolymer having a Mooney viscosity (ML1+4, 100° C.) of 40 to 110 as component (B), the amount of component (B) being 1 to 70 parts by weight based on 100 parts by weight of component (A).

Abstract: The present invention relates to a thermoplastic resin composition comprising 20 to 60 parts by weight of a rubber-reinforced resin (A) and 80 to 40 parts by weight of an aromatic polycarbonate (B) having an average molecular weight of 16,000 to 30,000 ((A)+(B)=100 parts by weight), said rubber-reinforced resin (A) containing a grafted rubber-like polymer (A1) obtained by polymerizing at least one compound (b) selected from the group consisting of aromatic vinyl compounds, vinyl cyanide compounds, (meth)acrylic ester compounds, acid anhydride monomeric compounds and maleimide-based compounds in the presence of a rubber-like polymer (a) having a glass transition temperature of not more than −40° C.

Abstract: A process of preparing a graft polymer (e.g., an ABS graft copolymer), which involves determining the concentration of at least one reaction component during the course of the reaction by means of Raman spectroscopy, is disclosed. The process, more particularly, comprises: (a) synthesizing the graft polymer from a reaction mixture comprising reactive components (e.g., monomers such as styrene and acrylonitrile, and a graft base); (b) analyzing the reaction mixture, at intervals, during the synthesis of the graft polymer, by means of Raman spectra; (c) recording the results of the Raman spectra analysis; (d) determining the concentration of at least one of said reactive components (e.g., styrene) by means of spectral evaluation of the recorded Raman spectra; and (e) terminating the synthesis reaction of the graft polymer when the concentration of at least one of the reactive components has reached a predetermined concentration value.

Abstract: Articles are formed from a thermosetting composition based on polybutadiene or polyisoprene resins which are subjected to a high temperature cure step of greater than 250° C. The thermosetting compositions may include fillers such as particulate ceramic fillers and may also include woven webs for improved dimensional stability and decreased brittleness. The formation process of this invention is particularly well suited for making electrical circuit substrates for microwave and digital circuits, typically in the form of the thermosetting composition being laminated on one or both opposed surfaces to metal conductive foil (e.g., copper).

Abstract: The present invention is directed to an epoxidized block copolymer composition comprising an epoxidized block copolymer (E) obtained by epoxidizing a block copolymer (C) comprising a polymer block (A) composed mainly of a vinyl aromatic hydrocarbon compound and a polymer block (B) composed mainly of a conjugated diene compound or a product (D) of hydrogenation of the block copolymer (C). The epoxidized block copolymer (E) meets at least one of the following requisites: (1) having a molar ratio (R) of contained hydroxyl to epoxy ranging from 0.001 to 0.

Abstract: An elastic-thermoplastic graft polymer prepared by a multi-stage free radical polymerization is described. The elastic-thermoplastic graft polymer is prepared by polymerizing (i) one or more monomers containing vinyl groups, and (ii) at least one molecular weight regulating compound, in the presence of (iii) at least one rubber in latex form. The ratio of monomers (M) to the molecular weight regulating compound (MWR) is altered throughout the various stages of the polymerization method. The M:MWR ratio is: from 50:1 to 400:1 in the first stage; from 100:1 to 800:1 in the second stage; and from 200:1 to 2000:1 in the third stage of the polymerization. In at least one further reaction stage of the polymerization, the monomers, in the absence of the molecular weight regulating compound, are polymerized in the presence of the rubber. This further reaction stage occurs before the first stage and/or after the third stage of the polymerization.

Abstract: The present invention discloses a process for manufacturing monovinylaromatic compounds containing an elastomer to provide increased toughness and strength. One particular embodiment of the invention discloses a process for manufacturing high impact polystyrene wherein styrene monomer containing a dissolved polybutadiene rubber is flowed into an elongated upflow stirred reactor containing three reaction zones, wherein the styrene and rubber are polymerized past the inversion point, then discharged to at least one additional reactor to continue their conversion to polymer.

Abstract: A process for forming a copolymer comprising the steps of (i) preparing a living polymer segment by using anionic polymerization techniques, (ii) modifying the living polymer by reacting it with an alkyl metal halide to form an organometallic polymeric intermediate, and (iii) preparing a second polymer segment from the organometallic polymeric intermediate by combining the intermediate, conjugated diene monomer, and a coordination catalyst that will polymerize the conjugated diene monomer.

Abstract: A continuous mass polymerization process for making an extrusion grade ABS resin having desirable properties and suitable for making refrigerator liners is disclosed. The process comprise charging a reaction mixture into a first in a series of reactors under conditions promoting polymerization, the mixture comprising diene rubber, a mixture of monomers, inert solvent and a chemical initiator to form a reaction mixture. The mixture is then transferred into a subsequent reactor operating at a temperature of 130 to 155° C. with no addition of chemical initiator and the resulting product is then devolatilized. The ABS thus produced contains about 10 to 16 pbw of dispersed rubber particles having an average particle diameter of 0.3 to 0.7 microns.

Abstract: Block copolymers comprise at least two hard blocks S1 and S2 made from vinyl aromatic monomers and, between these, at least ore random soft block B/S made from vinyl aromatic monomers and from dienes, where the proportion of the hard blocks is above 40% by weight, based on the total block copolymer, wherein the 1,2-vinyl content in the soft block B/S is less than 20%.

Abstract: In a process for polymerizing dienes in a solvent comprising vinylaromatic monomers, the polymerization is carried out in the presence of a metal compound of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo or W as catalyst and a Lewis acid as cocatalyst and, if desired, an alkylating agent and, if desired, a regulator. This process can be used for preparing high-impact polystyrene, acrylonitrile-butadiene-styrene copolymers or methyl methacrylate-butadiene-styrene copolymers.

Abstract: In a process for preparing thermoplastic molding compositions by a) polymerizing, in aqueous emulsion, dienes, C1-C12-alkyl acrylates or mixtures of these, where from 0 to 30% by weight of these monomers may have been replaced by other copolymerizable monomers, and where from 0 to 10 by weight of these monomers may have been replaced by crosslinking monomers, to give a rubber latex with a glass transition temperature below −10° C.

Abstract: The synthesis and characterization of star copolymers by living carbocationic copolymerization of statistical polymers comprising monomers of isobutylene (IB) and another monomer selected from the group consisting of styrene, isoprene and living carbocationically copolymerizable derivatives thereof is described. The poly(isobutylene-co-styrene) arms emanate from a calix[n]arene core where n preferably equals 8, forming an multi(octa)-arm star. The arms are advantageously fitted with crosslinkable termini such as allyl or hydroxyl end groups. The hydroxyl-terminated arm star copolymers are particularly suitable for use in coatings when reacted with crosslinking agents such as isocyanates.

Abstract: A process prepares impact-modified thermoplastic molding compositions which comprise a soft phase made from a rubber dispersed in a hard matrix composed of vinylaromatic monomers, where the hard matrix is prepared by anionic polymerization in the presence of a metal alkyl compound or a metal aryl compound of an element of the second or third main group, or of the second subgroup, of the Periodic Table.

Abstract: A method of preparing rubber substrate is provided. In the method, 50 to 95 parts by weight of conjugated diene monomer is first-polymerized, until the resulting first rubber substrate has gel content of 5 to 70 wt %. Thereafter, the first rubber substrate is second-polymerized with 5 to 50 parts by weight to obtain a second rubber substrate. The obtained second rubber substrate has higher gel content in core than outer layer.