Abstract: A vulcanizable rubber composition is provided that comprises an elastomer, a reinforcing filler comprising silica or a mixture thereof with carbon black, a silica dispersing aid comprising about 0.1 to about 15 phr poly(vinyl acetate) (PVA), and a cure agent. The addition of PVA to the composition improves the processability of the compound, improves the tear strength and modulus of the rubber and can reduce the number of mixing stages during compounding, resulting in lowering of the cost of operation and increasing plant productivity without compromising the processability or other physical properties of the stocks. Also provided are a vulcanizate formed from vulcanizing the rubber composition, a tire component formed from the vulcanized rubber and a process for forming the tire component.

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 silica-filled, vulcanized elastomeric compounds comprising an elastomer mixed with at least a silica filler, a processing aid, and a curing agent, and processes for the preparation of the same. Generally, the present invention provides processing aids which effectively reduce or replace the amount (i.e., about 10 percent by weight based upon the silica filler) of the processing aid bis[3-triethyoxysilyl)propyl]tetrasulfide (“Si69”) used in the production of silica-filled rubber stocks. These new processing aids include alkyl alkoxysilanes, fatty acid esters of hydrogenated and non-hydrogenated sugars and the polyoxyethylene derivatives thereof, and combinations thereof, with or without various non-reinforcing fillers such as mineral fillers. The processing aids do not hinder the physical properties of the compounds and have been found to be excellent substitutes for Si69.

Abstract: Novel solid supported anionic polymerization initiators that are multiply metalated with Group IA alkali metal atoms are provided and employed to produce extremely high molecular weight branched diene polymers. The initiators are prepared by metalating a particle comprising a thermoplastic polymer or a cured elastomer in the presence of a polar coordinator. The polymers obtained by anionic polymerization employing the initiators are multiply branched, with a polymer chain covalently attached to the particle at virtually every metalation site. The macro-branched polymers exhibit desirable properties, such as an extremely high molecular weight, a controlled molecular weight distribution, Tg and vinyl content, and the ability to readily absorb hydrocarbon solvents and oils. The polymers are easily compounded to form vulcanizable elastomeric compounds and articles that have excellent resistance to wear and tear and exhibit reduced hysteresis properties.

Abstract: The invention provides solid supported anionic catalysts, suitable for gas phase anionic polymerization of conjugated diene monomers, that are useful for anionically producing very high molecular weight branched diene polymers, such as styrene butadiene rubber, polybutadiene rubber, polyisoprene rubber, and the like. The catalysts comprise a metalatable particle, such as a bound rubber, a thermoplastic polymer or a cured elastomer, that is multiply metalated with Group IA alkali metal atoms. The multi-branched diene polymers obtained by gas phase anionic polymerization employing the catalysts exhibit desirable properties, such as an extremely high molecular weight, a controlled molecular weight distribution, Tg and vinyl content, and the ability to readily absorb hydrocarbon solvents and oils. The polymers are easily compounded to form vulcanizable elastomeric compounds and articles, such as tires, that have excellent resistance to wear and tear and exhibit reduced hysteresis properties.

Abstract: The invention provides solid supported anionic catalysts, suitable for gas phase anionic polymerization of conjugated diene monomers, that are useful for anionically producing very high molecular weight branched diene polymers, such as styrene butadiene rubber, polybutadiene rubber, polyisoprene rubber, and the like. The catalysts comprise a metalatable particle, such as a bound rubber, a thermoplastic polymer or a cured elastomer, that is multiply metalated with Group IA alkali metal atoms. The multi-branched diene polymers obtained by gas phase anionic polymerization employing the catalysts exhibit desirable properties, such as an extremely high molecular weight, a controlled molecular weight distribution, Tg and vinyl content, and the ability to readily absorb hydrocarbon solvents and oils. The polymers are easily compounded to form vulcanizable elastomeric compounds and articles, such as tires, that have excellent resistance to wear and tear and exhibit reduced hysteresis properties.

Abstract: The reduction of hysteresis in a silica-filled, vulcanized elastomeric compound is produced by mixing diene monomer and optionally monovinyl aromatic monomer with an initiator and a coordinator; effecting polymerization conditions; terminating polymerization with a terminator containing an organo-tin group to form a tin-coupled diene elastomer; compounding the tin-coupled diene elastomer with an amorphous silica filler and a vulcanization agent; and, effecting vulcanization. A pneumatic tire tread stock incorporating the vulcanized elastomer compound exhibits decreased rolling resistance in the tire.

Abstract: Diene polymers or copolymers having improved balance between raw polymer viscosity and mixed compound viscosity, useful in tire tread compositions having highly balanced wet traction, rolling resistance, and traction in ice and snow, and fracture properties in the cured and white carbon reinforced states are provided. These diene polymers or copolymers comprise a mixture of diene polymer or copolymer chains containing carbon-tin bonds in the main polymer or copolymer chains and diene polymer or copolymer chains containing terminals derived from hydrocarboxysilane compounds. The diene polymer or copolymers are prepared by first coupling a portion of the living diene polymer or copolymer chains obtained by anionic polymerization using a tin polyhalide coupling agent and then terminating the remaining living diene polymer or copolymer chains using hydrocarboxysilane compounds.

Abstract: A processable rubber stock is produced by the preparation of a silica-filled, vulcanized elastomeric compound comprising mixing an elastomer with an amorphous silica filler, from 0 to less than about 1% by weight based on said silica filler of bis[3-(triethoxysily)propyl]tetrasulfide, an alkylalkoxysilane and a cure agent. A further processing aid comprising at least one of an ester of a fatty acid or an ester of a polyol is preferred. The elastomer is preferably a diene monomer homopolymer or a copolymer of at least one diene and at least one monovinyl aromatic monomer. By effecting vulcanization, a vulcanized elastomeric compound is produced containing good physical properties for use as tread stock for a pneumatic tire.

Abstract: Incorporation of neutral water soluble inorganic salts into a precipitated silica improves the filler dispersion in a compounded rubber, reduces rolling resistance (hysteresis), and improves processability. These properties are achieved without loss of the expected reinforcement effect due to the substitution of inorganic salt for SiO2 in the silica. The properties are seen when a variety of silanes and processing aids are added to the silica.

Abstract: Novel solid supported anionic polymerization initiators that are multiply metalated with Group IA alkali metal atoms are provided and employed to produce extremely high molecular weight branched diene polymers. The initiators are prepared by metalating a particle comprising a thermoplastic polymer or a cured elastomer in the presence of a polar coordinator. The polymers obtained by anionic polymerization employing the initiators are multiply branched, with a polymer chain covalently attached to the particle at virtually every metalation site. The macro-branched polymers exhibit desirable properties, such as an extremely high molecular weight, a controlled molecular weight distribution, T.sub.g and vinyl content, and the ability to readily absorb hydrocarbon solvents and oils. The polymers are easily compounded to form vulcanizable elastomeric compounds and articles that have excellent resistance to wear and tear and exhibit reduced hysteresis properties.

Abstract: The invention provides solid supported anionic catalysts, suitable for gas phase anionic polymerization of conjugated diene monomers, that are useful for anionically producing very high molecular weight branched diene polymers, such as styrene butadiene rubber, polybutadiene rubber, polyisoprene rubber, and the like. The catalysts comprise a metalatable particle, such as a bound rubber, a thermoplastic polymer or a cured elastomer, that is multiply metalated with Group IA alkali metal atoms. The multi-branched diene polymers obtained by gas phase anionic polymerization employing the catalysts exhibit desirable properties, such as an extremely high molecular weight, a controlled molecular weight distribution, T.sub.g and vinyl content, and the ability to readily absorb hydrocarbon solvents and oils. The polymers are easily compounded to form vulcanizable elastomeric compounds and articles, such as tires, that have excellent resistance to wear and tear and exhibit reduced hysteresis properties.