Abstract: A golf ball having a core, and at least one layer about the core, wherein the core or the layer is formed from partially or fully neutralized butyl ionomers or their blends to improve the resiliency and impact durability over a conventional butyl rubber. The core comprises a thermoplastic material, a thermoset material, or a rubber-based material, while at least one layer is formed from a composition comprising a partially or fully neutralized butyl rubber ionomer. The butyl rubber ionomer comprises repeating units derived from at least one isoolefin monomer, at least 0.5 mol % of repeating units derived from at least one multiolefin monomer, at least 0.5 mol % of repeating units derived from an allylic halide, and at least 0.5 mol % of an ionomeric moiety. The isoolefin comprises isobutylene, the multiolefin comprises isoprene and the allylic halide comprises a bromide.

Abstract: This invention relates to a method for producing functionalized cis-1,4-polydienes having a combination of a high cis-1,4-linkage content and a high functionality, the resulting polymers and the vulcanized products containing the polymers. The functionalized cis-1,4-polydienes of the present invention are produced by a method comprising the steps of: (1) preparing a reactive polymer by polymerizing conjugated diene monomer with a lanthanide-based catalyst in the presence of less than 20% by weight of organic solvent based on the total weight of monomer, organic solvent, and resulting polymer, where the lanthanide-based catalyst is the combination of or reaction product of (a) a lanthanide compound, (b) an aluminoxane, (c) an organoaluminum compound other than an aluminoxane, and (d) a halogen-containing compound; and (2) contacting the reactive polymer with a functionalizing agent.

Abstract: Nucleophilic substitution reactions of halogenated elastomers and latent curatives are used to produce thermoset derivatives that are easily mixed at conventional compounding temperatures, but cure rapidly at conventional cure temperatures.

Abstract: Mixtures of halogenated elastomers and latent curatives are provided that cure when subjected to sufficient heat to decompose the latent curative. Decomposition products include CO2 and N-nucleophiles, which participate in nucleophilic substitution reactions leading to crosslinking of the elastomers. Transparent thermoset products that were free of voids were produced.

Abstract: A multi-functional polymer defined by the formula (Q-R¦n—Z—P2—Y where (Q-R)n is a functionality cluster, Q is a functional group, R is a multi-valent organic group, P2 is a long-chain polymer, n is an integer from about 2 to about 10, Y is a proton, a weak functional group, or a selective functional group, and Z is a branch point where the functionality clusters join the long-chain polymer.

Abstract: The present invention generally relates to singly-terminated polyisobutylene (PIB) compounds, and to a process for making such compounds. In one embodiment, the present invention relates to singly-terminated polyisobutylene compounds that contain only one primary alcohol, amine, or methacrylate group as the single-terminating group. In another embodiment, the present invention relates to singly-terminated polyisobutylenes carrying exactly one terminal alcohol, amine, or methacrylate group, where such singly-terminated polyisobutylenes have a number average molecular weight of about 500 to about 5000 grams per mole. In still another embodiment, the present invention relates to singly-terminated polyisobutylene compounds that can be used to synthesize polyurethanes, to polyurethane compounds made via the use of such polyisobutylene compounds, and to processes for making such compounds.

Abstract: The invention discloses improved processes to halogenate polymers. In particular, the invention discloses to improved processes to halogenate polymers made from C4-1012 isoolefins.

Abstract: This invention discloses a process for synthesizing a dendrimer of a rubbery polymer comprising: (a) reacting a lithium terminated rubbery polymer with a halogenated tin containing compound to produce a polymer which is terminated with halogenated tin moieties, wherein the halogenated tin containing compound is of the structural formula: wherein X represents a halogen atom, wherein Z1 groups can be the same or different and are selected from alkyl groups containing from 1 to 8 carbon atoms, wherein x represents an integer from 1 to 20, wherein the molar ratio of the lithium terminated rubbery polymer to halogen atoms in the halogenated tin containing compound is within the range of 2:n to (n?1):n, wherein n represents the number of halogen atoms that are bonded directly to tin atoms in the halogenated tin containing compound; (b) reacting the polymer which is terminated with halogenated tin moieties with a molar excess of a tertiary alcohol to produce a polymer which is terminated with hydroxy tin moietie

Abstract: This invention discloses a process for synthesizing a dendrimer of a rubbery polymer comprising: (a) reacting a lithium terminated rubbery polymer with a halogenated tin containing compound to produce a polymer which is terminated with halogenated tin moieties, wherein the halogenated tin containing compound is of the structural formula: wherein X represents a halogen atom, wherein Z1 groups can be the same or different and are selected from alkyl groups containing from 1 to 8 carbon atoms, wherein x represents an integer from 1 to 20, wherein the molar ratio of the lithium terminated rubbery polymer to halogen atoms in the halogenated tin containing compound is within the range of 2:n to (n?1):n, wherein n represents the number of halogen atoms that are bonded directly to tin atoms in the halogenated tin containing compound; (b) reacting the polymer which is terminated with halogenated tin moieties with a molar excess of a tertiary alcohol to produce a polymer which is terminated with hydroxy tin moietie

Abstract: This invention discloses a process for synthesizing a dendrimer of a rubbery polymer comprising: (a) reacting a lithium terminated rubbery polymer with a halogenated silicon containing compound to produce a polymer which is terminated with halogenated silicon moieties, wherein the halogenated silicon contain compound has at least four halogen atoms which are bonded directly to silicon atoms, wherein the ratio of the lithium terminated rubbery polymer to halogen atoms in the halogenated silicon containing compound is within the range of 2:n to (n-1):n, wherein n represents the number of halogen atoms that are bonded directly to silicon atoms in the halogenated silicon containing compound, wherein the halogenated silicon containing compound contains at least three halogen atoms which are bonded directly to a silicon atom; (b) reacting the polymer which is terminated with halogenated silicon moieties with a molar excess of a tertiary alcohol to produce a polymer which is terminated with hydroxy silyl moieties; a

Abstract: Article based on an elastomeric composition (C) comprising a crosslinked blend (B) of at least: (1) one substantially saturated synthetic elastomer; and (2) a copolymer containing repeating units derived from at least one conjugated diene and at least one ?,?-unsaturated nitrile, the article having been subjected to a surface halogenation treatment.

Abstract: A composition that includes functionalized polymers and particulate filler is provided. The composition includes at least three components: (1) a polymer that includes a first type of functionality such as a functional group including a primary or secondary amine functionality, (2) a polymer that includes a second type of functionality such as an alkoxysilane or other silica interacting functionality, and (3) at least two types of particulate filler. One of the functionalized polymers can be made in the presence of the other.

Abstract: The method for producing a modified conjugated diene based (co)polymer, according to the present invention comprises a step of reacting a conjugated diene based (co)polymer with a metal halide compound to obtain a modified conjugated diene based (co)polymer, the conjugated diene based (co)polymer having a weight-average molecular weight of 150,000 to 2,000,000 and being obtained by bonding, to a polymer having at least a conjugated diene unit, an alkoxysilyl group and an optionally protected primary amino group. The method can satisfactorily produce a conjugated diene based (co)polymer which has a high Mooney viscosity, excellent shape stability and good processability.

Abstract: A butyl rubber ionomer having improved adhesion to substrates whose surfaces have polar functional groups. Examples of such substrate materials include stainless steel, glass, mylar or Teflon®. The adhesion of the butyl rubber ionomer to the substrate is at least 25% greater than the adhesion of a non-ionomeric butyl rubber to the same substrate surface and with certain substrates is more than 150% greater. The adhesion is improved with increasing levels of multiolefin content in the butyl rubber ionomer. The adhesion is greatest for butyl rubber ionomers having a high multiolefin content (at least 3.5 mol% of multiolefin monomers or at least 1.5 mol % of residual multiolefins). By taking advantage of these high adhesion levels, a composite article can be formed between the butyl rubber ionomer and the substrate.

Abstract: The invention relates to novel air barriers made from elastomeric compositions. In particular, the invention relates to novel air barriers such as innerliners, air sleeves, and innertubes made from novel C4 to C7 isoolefin based polymers with new sequence distributions or that are substantially free of long chain branching.

Abstract: The present invention relates to a powder paint composition comprising at least (a) a thermosetting polymer having functional groups capable of reacting with ?-hydroxyalkylamide units (b) a compound comprising ?-hydroxyalkylamide units and (c) a deceleration agent, capable of reversibly blocking the functional groups of polymer (a). The deceleration agent is present in an amount sufficient to block at least 9% of the total amount of functional groups of polymer (a). The present invention relates also to the use of a specific amine compound as a deceleration agent in a powder paint composition.

Abstract: Copolymers of fluorinated polydienes and sulfonated polystyrene and their use in fuel cell membranes, batteries, breathable chemical-biological protective materials, and templates for sol-gel polymerization.

Abstract: This invention discloses a process for synthesizing a dendrimer of a rubbery polymer comprising: (a) reacting a lithium terminated rubbery polymer with a halogenated silicon containing compound to produce a polymer which is terminated with halogenated silicon moieties, wherein the halogenated silicon contain compound has at least four halogen atoms which are bonded directly to silicon atoms, wherein the ratio of the lithium terminated rubbery polymer to halogen atoms in the halogenated silicon containing compound is within the range of 2:n to (n?1):n, wherein n represents the number of halogen atoms that are bonded directly to silicon atoms in the halogenated silicon containing compound, wherein the halogenated silicon containing compound contains at least three halogen atoms which are bonded directly to a silicon atom; (b) reacting the polymer which is terminated with halogenated silicon moieties with a molar excess of a tertiary alcohol to produce a polymer which is terminated with hydroxy silyl moieties; a

Abstract: The present invention relates to a process for producing peroxide curable high multiolefin halobutyl ionomers prepared by reacting a halogenated butyl polymer having a high mol percent of multiolefin with at least one nitrogen and/or phosphorus based nucleophile. The resulting high multiolefin halobutyl ionomer comprises from about 2 to 10 mol % multiolefin. The present invention is also directed to the high multiolefin halobutyl ionomer.

Abstract: Anionically-polymerized living polymers are sequentially functionalized with certain agents X? and Y?. A method of preparing a functionalized polymer comprising the steps of reacting the polymer with a functionalizing agent X?, and then further reacting the polymer with a functionalizing agent Y?.

Abstract: The invention relates to new polymerization processes including diluents including hydrofluorocarbons and their use to produce novel halogenated polymers with new sequence distributions. In particular, the invention relates to halogenated copolymers of an isoolefin, preferably isobutylene, and a multiolefin, preferably a conjugated diene, more preferably isoprene, with new sequence distributions.

Abstract: The present invention relates to a continuous process for producing polymers at conversions ranging from 50% to 95% having a Mooney viscosity of at least 25 Mooney-units and a gel content of less than 15 wt. % containing repeating units derived from at least one isoolefin monomer, more than 4.1 mol % of repeating units derived from at least one multiolefin monomer and optionally further copolymerizable monomers in the presence of AlCl3 and a suitable proton source (e.g. water) or cationogen and at least one multiolefin cross-linking agent wherein the process is conducted in the absence of transition metal compounds and organic nitro compounds.

Abstract: A process for producing a conjugated diene copolymer rubber which comprises initiating a copolymerization reaction in a reaction system containing a first conjugated diene compound and a first aromatic vinyl compound and completing the reaction, adding a first polyfunctional monomer to the reaction system, optionally further adding a second conjugated diene compound and a second aromatic vinyl compound, and further conducting copolymerization reaction, and adding a modifier to the reaction system to react the modifier with the copolymer. A rubber composition having excellent processability, exhibiting sufficient hardness even after vulcanization, and possessing reduced rolling resistance can be obtained.

Abstract: A structural material of a polystyrene base and the reaction product of the polystyrene base and a solid phosphate ceramic is applied as a slurry which includes one or more of a metal oxide or a metal hydroxide with a source of phosphate to produce a phosphate ceramic and a poly (acrylic acid or acrylate) or combinations or salts thereof and polystyrene or MgO applied to the polystyrene base and allowed to cure so that the dried aqueous slurry chemically bonds to the polystyrene base. A method is also disclosed of applying the slurry to the polystyrene base.

Abstract: The present invention is directed to a method for synthesizing rubbery copolymers, such as styrene-butadiene rubber, or rubbery homopolymers, such as polybutadiene rubber, that are alkoxy functionalized, e.g., alkoxysilane functionalized, and provide desirable dispersion of silica in rubber compounds, such as for use in tire treads. To that end, the method, in one embodiment, involves admixing anionically polymerizable conjugated diene monomers with optional vinyl aromatic, an anionic-polymerization initiator, i.e., an organolithium compound, and a lithium alkoxide to form an admixture of living polymers, then adding a halogenated coupling agent to the admixture of living polymers effecting conditions to form an alkoxy functionalized rubbery polymer. The alkoxy functionalized rubbery polymers can be utilized in tire tread rubbers where the rubbery polymers may provide desirable wear properties without substantially sacrificing other performance characteristic(s), e.g., traction properties.

Abstract: A structural material of a polystyrene base and the reaction product of the polystyrene base and a solid phosphate ceramic. The ceramic is applied as a slurry which includes one or more of a metal oxide or a metal hydroxide with a source of phosphate to produce a phosphate ceramic and a poly (acrylic acid or acrylate) or combinations or salts thereof and polystyrene or MgO applied to the polystyrene base and allowed to cure so that the dried aqueous slurry chemically bonds to the polystyrene base. A method is also disclosed of applying the slurry to the polystyrene base.

Abstract: The present invention is directed to rubbery polymers, such as polybutadiene rubber or styrene-butadiene rubber, that contain tin coupling agents and provide desirable dispersion of carbon black in rubber compounds, such as for use in tire treads. The tin coupling agents are defined by the general formulas (I) (X3Sn)2O or (II) (X3Sn)O—(CH2)n—O(X3Sn), wherein X is a halogen and n is 1 to 20. A method of rubbery polymer synthesis, in one embodiment, involves mixing anionically polymerizable conjugated diene monomers with optional vinyl aromatic and an anionic-polymerization initiator, i.e., an organolithium compound, to form a mixture of living polymers. A tin coupling agent is added to the mixture of living polymers effecting polymerization conditions to form the tin coupled rubbery polymer. Such tin coupled rubbery polymers can be utilized in tire tread rubbers where the rubbery polymers may provide desirable wear properties without substantially sacrificing other performance characteristics.

Abstract: The present invention includes compositions suitable for air barriers such as innerliners where adhesion to tire carcass materials (e.g., SBR) and flexibility are desirable, as well as low air permeability. The invention includes a tire innerliner made by combining a filler; a sulfur cure system; optionally at least one secondary rubber; and at least one halogenated terpolymer of C4 to C8 isoolefin derived units, C4 to C14 multiolefin derived units, and p-alkylstyrene derived units. Examples of suitable fillers include modified carbon black, carbon black, silica, exfoliated clays, and combinations thereof. The present invention also includes a method of producing an elastomeric terpolymer composition comprising combining in a diluent C4 to C8 isoolefin monomers, C4 to C14 multiolefin monomers, and p-alkylstyrene monomers in the presence of a Lewis acid and at least one initiator to produce the terpolymer.

Abstract: This invention relates to a process for producing polymerisates by anionic polymerization in an inert reaction medium using conjugated dienes and vinylaromatic compounds in the presence of a catalyst, co-catalyst, and randomizer. Further, the invention relates to the polymerisates produced thereby and their uses.

Abstract: The present invention provides a method for preparing a copolymer useful for the manufacture of tires by coupling the ends of a living polymer, obtained from copolymerization of a diene monomers in the presence of an organolithium initiator and a hydrocarbon solvent, with a multi-reactive polysiloxane compound, and subsequently modifying the remaining uncoupled ends of the polymer with an amine compound. The use of the copolymer thus obtained for tire production improves the affinity to silica and greatly enhances the dynamic properties required for tires, such as wet traction and rolling resistance.

Abstract: A method for the surface treatment of rubber, a process for production of a rubber article, and a rubber composition wherein a structure derived from a fluorine compound containing a fluoroalkyl at both ends of its molecule are joined to a polymer main chain of crosslinked rubber in the vicinity of the surface of a rubber base (molding). The method involves causing the fluorine compound and a silane coupling agent to exist in the vicinity of the surface of a rubber base, and heat-treating the rubber base. The production process comprises compounding and mixing raw rubber and a silane coupling agent to obtaining a molding of crosslinked rubber and heating the molding. The rubber composition contains raw rubber, a crosslinking agent, the fluorine compound and a silane coupling agent.

Abstract: A structural material of a polystyrene base and the reaction product of the polystyrene base and a solid phosphate ceramic. The ceramic is applied as a slurry which includes one or more of a metal oxide or a metal hydroxide with a source of phosphate to produce a phosphate ceramic and a poly (acrylic acid or acrylate) or combinations or salts thereof and polystyrene or MgO applied to the polystyrene base and allowed to cure so that the dried aqueous slurry chemically bonds to the polystyrene base. A method is also disclosed of applying the slurry to the polystyrene base.

Abstract: This invention discloses a rubbery polymer which is comprised of repeat units that are derived from (1) at least one conjugated diolefin monomer, and (2) at least one functionalized monomer having of the structural formula: wherein R represents an alkyl group containing from 1 to about 10 carbon atoms or a hydrogen atom, and wherein R1 and R2 can be the same or different and represent hydrogen atoms or a moiety of the structural formula: wherein the R3 groups in repeat units and in different repeat units can be the same or different and represent hydrogen atoms or alkyl groups containing from 1 to about 4 carbon atoms, wherein n and x represents integers from 1 to about 10, with the proviso that R1 and R2 can not both be hydrogen atoms.

Abstract: Scavenger resins comprising pendant groups specific for the removal of primary amines form solution in the presence of secondary amines are provided. Processes for the use of these scavenger resins, especially in solid phase synthesis, for the removal of primary amines from solution or for the removal of electrophiles from solution are provided.

Abstract: A continuous process for manufacture of a polymer including branched and linear components comprising first polymerizing conjugated diene(s) in the presence of an organometallic initiator to a conversion that is at least 90% complete. A coupling agent is added to obtain a polymer including branched and linear components. The coupling agent is added at a ratio of about 0.3 to about 0.6 coupling equivalents to initiator equivalents.

Abstract: An adhesive composition and tapes utilizing the adhesive compositions are disclosed. A tape utilizing the adhesive composition of the present invention particularly suitable for use in closure systems associated with air ducts and air connectors is disclosed. A composition particularly suitable for use as an antioxidant in adhesive compositions is disclosed.

Abstract: The invention provides chain-coupled polymeric sulfide compounds for use as the elastomeric component in vulcanizable elastomeric compositions comprising silica, carbon black or mixtures thereof. In particular, the invention provides anionically polymerized polymers having polymer chain living ends that are functionalized with sulfide groups and coupled together by a metal or nonmetal atom. The chain-coupled polymeric sulfide compounds have an initial high viscosity for ease of handling prior to compounding, a stable viscosity during storage, and a decreased compound viscosity for better filler dispersion and improved mixing efficiency. The invention further provides a pneumatic tire having at least one component produced from the vulcanizable elastomeric composition of the invention. A tire tread produced from vulcanized elastomers exhibiting these improved properties will exhibit reduced hysteresis resulting in an increase in rebound and improved rolling resistance and wet traction.

Abstract: The present invention provides block copolymers with semifluorinated LC side groups (single or monodendron groups). The block copolymers can be blended with a thermoplastic elastomer block copolymer, e.g., styrene-ethylene/butylene-styrene (SEBS) to provide a surface active block copolymer (SABC).

Abstract: A golf ball is provided that includes a molded resilient inner core made of a rubber compound and a polymeric cover surrounding the inner core. The rubber compound is a halo-butyl rubber polymer and a carbon black filler in an amount of 80% to 100% by weight of the total rubber component.

Abstract: This invention discloses a rubbery polymer which is comprised of repeat units that are derived from (1) at least one conjugated diolefin monomer, and (2) at least one functionalized monomer having of the structural formula: wherein R represents an alkyl group containing from 1 to about 10 carbon atoms or a hydrogen atom, and wherein R1 and R2 can be the same or different and represent hydrogen atoms or a moiety selected from the group consisting of wherein R3 groups can be the same or different and represent alkyl groups containing from 1 to about 10 carbon atoms, aryl groups, allyl groups, and alkyloxy groups of the structural formula —(CH2)y—O—(CH2)z—CH3, wherein Z represents a nitrogen containing heterocyclic compound, wherein R4 represents a member selected from the group consisting of alkyl groups containing from 1 to about 10 carbon atoms, aryl groups, and allyl groups, and wherein n, x, y and z represents integers from 1 to about 10, with the

Abstract: A polymerization process comprising the steps of admixing a halogen-containing compound, monomer, and a cobalt complex.

Abstract: A polymer nano-particle composition is provided. The composition includes polymer nano-particles having a poly(alkenylbenzene) core and a surface layer comprising a crystalline polyolefin. The nano-particles preferably have a mean average diameter of less than about 100 nm.

Abstract: Metal salts of cyclic alcohols can be used as modifiers in lithium initiated solution polymerizations of diene monomers into rubbery polymers having a low vinyl content. For instance, such initiator systems can be used in the copolymerization of styrene and isoprene to produce low vinyl styrene-isoprene rubber having a random distribution of repeat units that are derived from styrene. It is important for such polymerizations to be conducted in the absence of polar modifiers, such as Lewis bases. The subject invention more specifically discloses an initiator system which is comprised of (a) a lithium initiator and (b) a metal salt of a cyclic alcohol, wherein said initiator system is void of polar modifiers. The present invention also discloses a process for preparing a rubbery polymer having a low vinyl content which comprises: polymerizing at least one diene monomer with a lithium initiator at a temperature which is within the range of about 5° C. to about 100° C.

Abstract: A novel and improved EPDM formulation for a solid propellant rocket motor is described wherein hexadiene EPDM monomer components are replaced by alkylidene norbornene components and with appropriate adjustment of curing and other additives functionally-required rheological and physical characteristics are achieved with the desired compatibility with any one of a plurality of solid filler materials, e.g. powder silica, carbon fibers or aramid fibers, and with appropriate adhesion and extended storage or shelf life characteristics.

Abstract: A continuous process for manufacture of a polymer including branched and linear components comprising first polymerizing conjugated diene(s) in the presence of an organometallic initiator to a conversion that is at least 90% complete. A coupling agent is added to obtain a polymer including branched and linear components. The coupling agent is added at a ratio of about 0.3 to about 0.6 coupling equivalents to initiator equivalents.

Abstract: Polymers comprising fluorinated vinyl alcohol units and having acid labile groups partially introduced are novel. Using such polymers, resist compositions featuring transparency to excimer laser light and alkali solubility are obtained.

Abstract: The present invention relates to the post-polymerization fluorination methods of polymers produced via ring-opening metathesis polymerization. Unlike prior art methods that result in low product yields and generally involve chemically aggressive reagents, the inventive methods produce fluorinated polymers in quantitative yields and under mild conditions. In preferred embodiments, a source of difluorocarbene is reacted with the desired polydiene to form a fluorinated polymer product. In preferred embodiments, the source of difluorocarbene is hexafluoropropylene oxide and the polydiene is poly-dicyclopentadiene (“poly-DCPD”). Fluorination and the concomitant removal of unsaturated bonds result in polymers having improved physical properties such as improved strength characteristics, enhanced oxidative and chemical stability, and low surface energies.

Abstract: The process and catalyst system of this invention can be utilized to synthesize a highly random styrene-butadiene rubber having a high trans content by solution polymerization. The styrene-butadiene rubber made by the process of this invention can be utilized in tire tread rubbers that exhibit improved wear characteristics. This invention more specifically reveals a catalyst system for use in isothermal polymerizations which consists essentially of (a) an organolithium compound, (b) a calcium alkoxide and (c) a lithium alkoxide. The subject invention further discloses a process for synthesizing a random styrene-butadiene rubber having a low vinyl content by a process which comprises copolymerizing styrene and 1,3-butadiene under isothermal conditions in an organic solvent in the presence of a catalyst system which consists essentially of (a) an organolithium compound, (b) a calcium alkoxide and (c) a lithium alkoxide.

Abstract: Disclosed is a process for producing thermally stabilized styrenic polymers and products produced thereby wherein a pre-formed styrenic polymer is functionalized with a bifunctional Friedel-Crafts-type alkylation or acylation agent to yield a functionalized styrenic polymer. The functionalized polymer is admixed with a Friedel-Crafts-type catalyst, preferably a phosphate ester, and optionally a base, such that the functionalized polymer will experience inter- and intramolecular cross-linking reactions at elevated temperatures, thereby stabilizing the polymer from further thermal degradation.

Abstract: This invention discloses a process for synthesizing random styrene-isoprene rubber comprising: (1) continuously charging isoprene, styrene, an initiator, and a solvent into a first polymerization zone, (2) allowing the isoprene and styrene to copolymerize in the first polymerization zone to total conversion of 60 to 95 percent to produce a polymer cement containing living styrene-isoprene chains, (3) continuously charging the polymer cement containing living styrene-isoprene chains and additional isoprene monomer into a second polymerization zone, wherein from 5 to 40 percent of the total amount of isoprene changed is charged into the second polymerization zone, (4) allowing the copolymerization to continue in the second polymerization zone to a conversion of the isoprene monomer of at least 90 percent wherein the total conversion of styrene and isoprene in the second polymerization zone is limited to a maximum of 98 percent, (5) withdrawing a polymer cement of random styrene-isoprene rubber having living cha