Abstract: A polymer nano-particle composition is provided, wherein the nano-particle includes a poly(alkenylbenzene) core and a surface layer including poly(conjugated diene). The polymer nano-particles are preferably less than about 100 nm in diameter. The nano-particles can be made by a dispersion polymerization process.

Abstract: A process for polymerizing 1,3-butadiene into a low molecular weight high-cis polybutadiene is described using a catalyst system comprising: (a) a neodymium-containing compound, (b) an aluminoxane or a trialkyl aluminum compound, (c) an organoaluminum hydride, and (d) a halogen source. A blend of a high molecular weight high-cis polybutadiene and the low molecular weight high-cis polybutadiene is also disclosed for use in pneumatic tire treads. Desirably both the high and the low molecular weight polymers have high cis contents, with the low molecular weight polymer being at least 70 percent cis and the high molecular weight polymer being at least 92 percent cis. Desirably both polymers are made with a neodymium catalyst system. The blends provide a balance of properties including good snow traction, wet traction, and rolling resistance while providing a balance of good physical properties including tension at break, modulus etc.

Abstract: A band element for mounting in the crown portion of a pneumatic tire to provide run flat ability to the tire in the event of loss of air pressure and to provide increased puncture resistance. The band is formed of flat strips of tape having fibers embedded in a resin matrix which are twisted and then pultrated to provide a rectangular cross sectional configuration. The twisted tape is wrapped about a mandrel and forms either the only layer, or the intermediate layer of a composite band in combination with inner and outer layers of flat tape or wound filament fibers, whereby the fibers in the tape extend across the central axis of the band to reduce interlaminar sheer. In another embodiment, a plurality of dimples or depressions are formed in the individual tape layers to extend a plurality of the fibers across the layer boundaries to reduce interlaminar sheer.

Abstract: The invention improves tire flat spotting by providing a bead assembly that has bead filler elements disposed outside the body cords so that the turn up portion of the ply of body cords is disposed immediately back against the main portion of the ply of body cords above the bead core. This carcass structure increases the stiffness of the lower sidewall and decreases the flat spotting experience by the tire. In one embodiment of the invention, a reinforcing ply is wrapped around the bead filler elements to further increases the stiffness of the lower sidewall. In another embodiment, a bead filler element is disposed inside the body cords so that an air pocket is not formed in the carcass during the manufacturing process.

Abstract: A butadiene-type polymer suitable for use as a processing aid in a rubber composition is formed by polymerizing butadiene or other conjugated diene monomers in a solvent, such as hexane, to form a polymer of relatively low molecular weight (around 30-40,000 g/mole). The polymer is coupled with a coupling agent, such as tin tetrachloride, to increase its molecular weight to a level at which conventional desolventizing processes may be used to remove the solvent from the mix. After desolventizing, the polymer is decoupled, by heating, to return the polymer to its original molecular weight.

Abstract: The invention provides a sulfur vulcanizable silica-reinforced elastomeric compound having improved tensile mechanical and dynamic viscoelastic properties. The compounds are formed by mixing an elastomer optionally having an alkoxysilane terminal group, with silica in the presence of an alkyl alkoxysilane for desired processability and a mercaptosilane for increasing the bound rubber content. In particular, the mercaptosilane and the alkyl alkoxysilane are present in a ratio of a maximum of 0.14:1. Preferably, the mercaptosilane and the alkyl alkoxysilane are compounded with the elastomer and the silica at high temperature in the first mixing stage.

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: 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-(triethoxysilyl)propyl]tetrasulfide, an alkylalloxysilane 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: 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 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: 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.