Abstract: A polymer composition for a tire having an air permeation coefficient of 25×10−12 cc·cm/cm2·sec ·cmHg (at 30° C.) or less and a Young's modulus of 1 to 500 MPa, including (A) at least 10% by weight, based on the weight of the total polymer component, of at least one thermoplastic resin having an air permeation coefficient of not more than 25×10−12 cc·cm/cm2·sec·cmHg (at 30° C.) and a Young's modulus of more than 500 MPa and (B) at least 10% by weight, based on the total weight of the polymer component, of at least one elastomer component having an air permeation coefficient of more than 25×10−12 cc·cm/cm2·sec·cmHg (at 30° C.) and a Young's modulus of not more than 500 MPa, wherein the total amount (A)+(B) of the component (A) and the component (B) is not less than 30% by weight based on the weight of the total polymer component, and a pneumatic tire obtained therefrom.

Abstract: A rubber composition for a tire tread comprising (1) (i) 60 to 90 parts by weight of natural rubber and/or polyisoprene rubber, (ii) 10 to 35 parts by weight of a high cis polybutadiene rubber having a melt viscosity of 90 to 150 cps and a cis content of 90% by weight or more, and (iii) 0.5 to 5 parts by weight of an A-B type block copolymer composed of (A) a poly(styrene-butadiene) or polybutadiene block having a styrene content (St) of 0 to 35% by weight and a butadiene content (Bd) of 65 to 100% by weight, having a 1,2-vinyl bond content (Vn) of 5 to 80 mol %, and satisfying the relationship of Vn≦2St+30 and (B) a polyisoprene block having a cis content of at least 70% by weight, in a ratio by weight (A)/(B) of 20 to 80/80 to 20, and (2) 40 to 60 parts by weight of carbon black having an N2SA of 125 m2/g or more.

Abstract: A thermoplastic elastomer composition dynamically vulcanized to a gelation rate of 50 to 95% which is superior in heat resistance and durability while maintaining flexibility and superior in air permeation preventive property which can be efficiently used as, for example, a pneumatic tire as an air permeation preventive layer. In particular, a thermoplastic elastomer composition having a reduced particle size of the domain rubber is produced by a material having a high rubber ratio by mixing a composition (C) mixed under conditions of a ratio of melt viscosities of the rubber composition (A)/resin (B) of 0.8 to 1.2 and the formula (&phgr;A/&phgr;B)×(&eegr;B/&eegr;A)<1.0 under conditions of a ratio of melt viscosities of the rubber composition (D)/composition (C) of 0.8 to 1.2 and the formula (&phgr;D/&phgr;C)×(&eegr;C/&eegr;D)<1.

Abstract: A process for production of a modified carbon black, at a cheaper cost, for rubber reinforcement having the superior tan &dgr; temperature dependency of silica and an excellent abrasion resistance and further having no problems arising due to a low electrical conductivity is provided.

Abstract: A polysiloxane composition comprising (A) a polysiloxane having a group represented by the formula (I): ≡Si—OR  (I) wherein, R is a C1 to C18 substituted or unsubstituted monovalent hydrocarbon group or ether bond containing an organic group; and (B) at least 1 ppm of (a) a compound having an N, P, S, Sn, or As component or (b) an acetylene alcohol and a rubber composition containing the same. Specific polysiloxanes (A) contain both formula (I): ≡Si—OR as well as Si—H.

Abstract: A block copolymer (1) containing a polymer block A of a conjugated diene and a random copolymer block B of a conjugated diene and aromatic vinyl compound, (2) having a weight ratio (A:B) of the polymer block A and the copolymer block B of 5:95 to 95:5, (3) having a bound aromatic vinyl compound content in the copolymer block B of 1 to 50% by weight, (4) having a weight average molecular weight (Mw) of 100,000 to 5,000,000, and (5) having at least two transition points measured by differential scanning calorimetry in the range of −150° C. to +150° C., a method of production of the same, and a rubber composition and pneumatic tire containing the same.

Abstract: A thermoplastic elastomer composition which, when used for the inner tube and/or outer cover of a hose, can improve the hose flexibility at an ordinary temperature and low temperature, oil resistance, and cold resistance and can reduce the production costs since it does not require a vulcanization step and a hose having said properties using this elastomer composition for its inner tube and/or outer cover and a process and apparatus for the production thereof.

Abstract: A rubber composition having improved properties containing a starting rubber (e.g., diene rubber) and a polysiloxane having the following alkoxysilyl group (I) and/or acyloxysilyl group (II) and having an average degree of polymerization of 3 to 10,000: ≡Si—OR1  (I) ≡Si—OCOR2  (II) wherein, R1 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms or an organic group containing an ether bond and R2 is hydrogen or a hydrocarbon group having 1 to 21 carbon atoms.

Abstract: A rubber composition having improved properties containing a starting rubber (e.g., diene rubber) and a compounding agent consisting of a silane coupling agent and a carbon black, calcium carbonate or stearic acid powder impregnated with a polysiloxane having the following alkoxysilyl group (I) and/or acyloxysilyl group (II) and having an average degree of polymerization of 3 to 10,000:.tbd.Si--OR.sup.1 (I).tbd.Si--OCOR.sup.2 (II)wherein, R.sup.1 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms or an organic group containing an ether bond and R.sup.2 is hydrogen or a hydrocarbon group having 1 to 21 carbon atoms.

Abstract: A polymer composition for a tire having an air permeation coefficient of 25.times.10.sup.-12 cc.multidot.cm/cm.sup.2 .multidot.sec.multidot.cmHg (at 30.degree. C.) or less and a Young's modulus of 1 to 500 MPa, including (A) at least 10% by weight, based on the weight of the total polymer component, of at least one thermoplastic resin having an air permeation coefficient of not more than 25.times.10.sup.-12 cc.multidot.cm/cm.sup.2 .multidot.sec.multidot.cmHg (at 30.degree. C.) and a Young's modulus of more than 500 MPa and (B) at least 10% by weight, based on the total weight of the polymer component, of at least one elastomer component having an air permeation coefficient of more than 25.times.10.sup.-12 cc.multidot.cm/cm.sup.2 .multidot.sec.multidot.cmHg (at 30.degree. C.

Abstract: (i) A starting rubber (A) comprising a terminal-modified and/or coupled diene rubber and having an average glass transition temperature TgA (.degree. C.) is mixed with a specific amount of the reinforcing agent are mixed at a temperature of at least 135.degree. C., followed by adding a starting rubber (B) comprising a terminal unmodified diene rubber and having a specific average glass transition temperature TgB (.degree. C.), and the remaining reinforcing agent and a softening agent; (ii) a starting diene rubber (A') having a specific weight average molecular weight Mw(A') and average glass transition temperature TgA' (.degree. C.) is contacted with a reinforcing agent, followed by adding a starting diene rubber (B') having a specific weight average molecular weight Mw(B) and average glass transition temperature TgB' (.degree. C.

Abstract: A pneumatic tire having an air permeation preventive layer comprising a low permeability thermoplastic elastomer composition comprising a thermoplastic elastomer having a thermoplastic resin composition as a continuous phase and a rubber composition as a dispersed phase, in which a barrier resin composition is contained, which low permeability thermoplastic elastomer composition has a phase structure in which the barrier resin composition is dispersed in the form of a flat state in the thermoplastic elastomer, is abundant in flexibility, is superior in gas permeation preventive property, and enables the tire to be reduced in weight.

Abstract: A rubber composition having improved properties containing a starting rubber (e.g., diene rubber) and a compounding agent comprising a mixture of a polysiloxane having the following alkoxysilyl group (I) and having an average degree of polymerization of 3 to 10,000:.tbd.Si--OR.sup.1 (I).tbd.Si--OCOR.sup.2 (II)wherein, R.sup.1 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms or an organic group containing an ether bond and R.sup.2 is hydrogen or a hydrocarbon group having 1 to 21 carbon atoms, and a sulfur containing silane.

Abstract: A process for producing surface-treated carbon black for rubber reinforcement comprising: a surface treatment reaction step of dispersing carbon black for rubber reinforcement in water, followed by reacting a metal silicate and an acid in the dispersion to thereby deposit amorphous silica on the surface of the carbon black; and a subsequent aging step of bringing the pH of the dispersion to not more than 7.

Abstract: A process for producing surface-treated carbon black for rubber reinforcement characterized by providing carbon black and organosiloxane together; and then heating the mixture to a temperature of 60.degree. C. to 200.degree. C. to deposit a silicon dioxide residue on the surface of the carbon black and a rubber composition using the same.

Abstract: A carbon-containing rubber composition containing a rubber composition containing carbon black, obtained by coagulating, dehydrating, and drying a rubber latex mixture containing a latex of at least one starting rubber A having an average glass transition temperature TgA of -120.degree. C. to -15.degree. C., carbon black, and part of a softening agent, mixed in an internal mixer with a starting rubber B and part of the softening agent, with a ratio F.sub.A /F.sub.B of the concentration F.sub.A of carbon black in the copolymer in the rubber latex mixture with the concentration F.sub.B of carbon black in the copolymer after kneading by the hermetic mixture being 1.2 to 3.0 and a rubber composition containing carbon black comprising a starting rubber A' comprising a polymer having functional groups represented by formula (I)--C.dbd.

Abstract: A thermoplastic elastomer composition comprising:i) from 15 to 80 parts by weight of a polyamide thermoplastic resin as component A;ii) from 20 to 85 parts by weight of a rubber composition as component B, the rubber composition containing a copolymer rubber composed of a copolymer of a C.sub.4 to C.sub.7 isomonoolefin and a p-alkylstyrene, where at least a part of the p-alkylstyrene unit portions thereof have a halogen atom; andiii) a cross-linking agent,wherein the thermoplastic resin component A forms a continuous phase and at least part of component B is dispersed in component A as a dispersed phase and at least part of the dispersed phase is cross-linked by the cross-linking agent.

Abstract: A rubber composition containing at least one rubber component containing a diene rubber and a rubber reinforcing carbon black having silica deposited on the surface thereof.

Abstract: Rubber compositions for automotive tire treads are made up of a selected class of base rubbers and a selected class of synthetic plasticizers in specified amounts. The plasticizer is derived from esterification of a diglycerin or an alkylene oxide adduct of a polyhydric alcohol with a selected class of higher fatty acids. Gripping performance is maintained for a prolonged period of time.

Abstract: A process for producing a rubber composition comprising (i) a total amount of 100 parts by weight of starting rubbers (A) and (B), including 30 to 90 parts by weight of the starting rubber (A) having a glass transition temperature (Tg) of -40.degree. to 10.degree. C. and 10 to 40 parts by weight of the starting rubber (B) which is viscoelastically incompatible with the starting rubber (A) and has a Tg of at least 20.degree. C. lower than the Tg of the starting rubber (A) and (ii) 60 to 100 parts by weight of a reinforcing agent, wherein the starting rubber (A) and at least 80% by weight of the total weight of the reinforcing agent are mixed in a hermetic type mixer at 130.degree. C. to 200.degree. C. for at least 10 seconds, then the starting rubber (B) and the remaining reinforcing agent are added and mixed.