Abstract: A rubber composition which comprises a rubber ingredient comprising a diene rubber and a reinforcing agent comprising silica; said diene rubber being a copolymer comprising (1) 30 to 85% by weight of conjugated diene monomer units, (2) 15 to 50% by weight of aromatic vinyl monomer units and (3) 0.05 to 20% by weight of units of a vinyl monomer having a polar group, and the diene rubber having in the molecule an alkylthio group having 12 to 16 carbon atoms, which include at least three tertiary carbon atoms, and having a sulfur atom which is directly bound to at least one of the tertiary carbon atoms.

Abstract: The present invention provides a rubber composition comprising 100 parts by weight of a diene rubber component, 10 to 200 parts by weight of a reinforcing agent, and 0.1 to 15 parts by weight of a fatty acid salt. For example, the diene rubber preferably comprises a diene rubber having a heteroatom-containing polar group, the reinforcing agent preferably comprises carbon black or silica, and the fatty acid salt preferably comprises a metal salt of a C5 to C36 fatty acid. This rubber composition yields a vulcanized rubber showing improvements in heat build-up, tensile strength, abrasion resistance and processability.

Abstract: The invention provides a rubber composition comprising 100 parts by weight of a diene rubber (i) and 0.1 to 25 parts by weight of a polyether-based polymer (ii).

Abstract: This invention provides a diene rubber capable of yielding a vulcanized rubber having improved heat build-up, tensile strength and abrasion resistance, processes for preparing the same, and rubber compositions containing the same. The diene rubber is composed of 40 to 99.99% by weight of conjugated diene monomer units, 0 to 50% by weight of aromatic vinyl monomer units, and 0.01 to 20% by weight of vinyl monomer units containing a tertiary amino group which is at least partially quaternized with a hydrocarbon radical, and has a Mooney viscosity (ML1+4, 100° C.) of 10 to 200.

Abstract: The invention provides a diene polymer composition composed of a branched diene polymer component (A) having at least three branched diene polymer chains through a polyfunctional coupling agent and a linear diene polymer component (B) having a quaternary ammonium group, and having a weight average molecular weight (Mw) within a range of from 100,000 to 2,000,000, a preparation process of the diene polymer composition, and a rubber composition comprising a rubber component containing the diene polymer composition, and a reinforcing agent.

Abstract: A diene rubber comprised of a conjugated diene homopolymer or a conjugated diene/aromatic vinyl copolymer; the homopolymer or copolymer having on at least one end of its polymer chain a quaternary ammonium group to which four carbon atoms have been bound; at least 10% of the bound conjugated diene units being a vinyl bond; and the homopolymer or copolymer further having a weight average molecular weight (Mw) of 100,000 to 2,000,000. This rubber exhibits well reduced heat build-up, which is an index of a well reduced rolling resistance, and having tensile strength and abrasion resistance.

Abstract: Disclosed herein are a diene rubber composition comprising 100 parts by weight of a diene rubber component composed of 10-100 wt. % of an amino group-containing diene copolymer rubber (A) having a composition (based on the bound amount) of 40-99.95 wt. % of a conjugated diene monomer, 0.05-20 wt. % of an amino group-containing monomer and 0-55 wt. % of an aromatic vinyl monomer, and 0-90 wt. % of another diene rubber (B), and 10-150 parts by weight of silica having a specific surface area of 50-220 m.sup.2 /g as determined by nitrogen absorption (BET method), and having excellent heat build-up resistance, tensile properties, abrasion properties and processability, and a preparation method thereof.

Abstract: This invention provides a diene rubber composed of 40 to 99.99% by weight of conjugated diene units, 0.05 to 20% by weight of amino-containing vinyl monomer units, 0.05 to 20% weight of hydroxyl-containing vinyl monomer units, and 0 to 50% by weight of other copolymerizable monomer units, and having a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 10 to 200. This diene rubber yields a vulcanized rubber showing improvements in heat build-up, tensile strength, abrasion resistance and processability.

Abstract: The invention provides a rubber composition comprising 100 parts by weight of a diene rubber (i) and 0.1 to 25 parts by weight of a polyether-based polymer (ii).

Abstract: There is provided a silica-containing diene rubber composition superior in resiliene (which is an indication of rolling resistance), at least equal, in tensile strength and abrasion resistance, to carbon black-containing diene rubber compositions, and good in processability and hardness property. The silica-containing diene rubber composition is characterized by containing, as the diene rubber component, a hydroxyl group-containing diene rubber having a weight-average molecular weight of 50,000 or more, or a blend of the hydroxyl group-containing diene rubber and other diene rubber.

Abstract: Disclosed herein are a rubber composition comprising a diene rubber and silica, wherein (i) the silica is compounded in a proportion of 10-150 parts by weight per 100 parts by weight of the diene rubber, and (ii) a silicone oil having a polar group at its side chain or terminal is compounded in a proportion of 0.1-50 parts by weight per 100 parts by weight of the silica, and has excellent rebound resilience, tensile property, abrasion property and processability, and a preparation process thereof.

Abstract: A rubber composition comprising 100 parts by weight of a diene rubber ingredient containing an amino group-containing diene rubber, 10 to 120 parts by weight of silica, 0.1 to 15 parts by weight a vulcanizer and 0.1 to 15 parts by weight of a sulfenamide vulcanization accelerator.This rubber composition exhibits excellent heat build-up, tensile property and abrasion resistance, and is suitable for tires and others.

Abstract: A rubber composition comprising (1) a rubber ingredient comprising a diene polymer rubber having a primary amino group, and (2) silica. The diene polymer rubber having a primary amino group is obtained by allowing a diene polymer having an active metal bound to the polymer molecule, to react with a N-unsubstituted aziridine compound. The rubber composition is made advantageously by a process wherein the above-mentioned rubber ingredient is mixed with silica, and then, additives other than the silica are incorporated in the rubber ingredient/silica mixture. The rubber composition exhibits good rebound resilience tensile properties and abrasion resistance.

Abstract: A process for preparation of latex of a hollow polymer which comprises adding a base, in the presence of a monomer, to latex containing carboxy-modified copolymer particles to make the pH of the latex 8 or more; adding a carboxyl group-containing monomer to make the pH of the latex 7 or less; and then polymerizing these monomers.

Abstract: A process for producing polymer particles containing one microvoid or two or more discrete microvoids, which comprises(1) adding a base to a latex of a carboxyl-modified copolymer containing 0.1 to 1000 parts of an organic solvent per 100 parts by weight of the carboxyl-modified copolymer to neutralize at least part of the carboxyl groups in the copolymer, and(2) adding an acid to the latex to adjust the pH of the latex to not more than 7.