Abstract: A process for producing a modified polymer having, in the molecule thereof, an organic group(s) introduced thereinto and derived from a compound(s) having a free radical comprising reacting a polymer such as an elastomer with a compound having the free radical stable at an ordinary temperature in the presence of oxygen, after or while a carbon radical(s) is generated in the polymer, whereby the modified polymer having an improved bondability and processability is formed.

Abstract: A method for producing an elastomer composition comprising allowing a cross-linked elastomer composition in the presence of (A) a fluid composed of a gaseous substance at an ordinary temperature and an ordinary pressure at a high pressure and (B) at least one component selected from a cross-linkable or polymerizable monomer, oligomer and polymer to thereby impregnate the component (B) into the cross-linked elastomer composition, then cross-linking or polymerizing the impregnated composition.

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. The method includes 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 (?A/?B)×(?B/?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 (?D/?C)×(?C/?D)<1.0, wherein ?A: volume fraction of rubber composition (A), ?B: volume fraction of resin (B), ?A: melt viscosity of rubber composition (A), ?B: melt viscosity of resin (B), ?C: volume fraction of composition (C), ?D: volume fraction of rubber composition (D), ?C: melt viscosity of composition (C), ?D: melt viscosity of rubber composition (D).

Abstract: A thermoplastic polymer having a carbonyl-containing group and a nitrogen-containing 5-membered heterocycle-containing group in side chains, and a composition thereof. The thermoplastic polymer and composition thereof have excellent recycle property in that physical properties do not deteriorate even though formation of crosslinking and dissociation of crosslinking are repeatedly conducted with altering temperature. The thermoplastic polymer and composition thereof are that its crosslinked structure is considerably stable at room temperature, and therefore have considerably high tensile strength. In particular, in the case of bonding to a main chain at 3-position or 4-position of a nitrogen-containing 5-membered heterocycle, intermolecular hydrogen bond is caused, so that a cured product has high mechanical properties.

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 process for producing a modified carbon black for rubber reinforcement comprising: adding, to carbon black, water-dispersed silica and an organosilane compound having the formula (I): R1n—Si—(OR2)4-n  (I) wherein R1 represents a hydrocarbon group having 1 to 10 carbon atoms, R2 represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, n is 1 or 2, and R1 and R2 may be the same or different, and mixing and dispersing the mixture.

Abstract: A radical-modified polymer having a free radical compound stable in the presence of oxygen at an ordinary temperature at the end of the molecule thereof or in the molecular chain thereof and a polymer composition containing the same.

Abstract: A viscoelasticity improving agent for rubber obtained by reacting an alkyllithium compound with a free radical compound having an isocyanate group in the molecule thereof and existing stably at room temperature in the presence of oxygen and a rubber composition.

Abstract: A rubber composition comprising (i) an incompatible polymer blend of at least two diene rubbers selected from rubbers containing a conjugated diene and, optionally, an aromatic vinyl monomer and forming two polymer phases (A) and (B), and (ii) 0.1 to 20 parts by weight, based upon 100 parts by weight of the total polymer component including the block copolymer, of a block copolymer having at least two mutually incompatible blocks (a) and (b), wherein the block (a) is compatible with the polymer phase (A) and incompatible with the polymer phase (B) and the block (b) is compatible with the polymer phase (B) and incompatible with the polymer phase (A), and composed of a conjugated diene and, optionally, an aromatic vinyl monomer, and wherein the molecular weights of the polymers forming the polymer phases (A) and (B) satisfy the specified equations (I) and (II) mentioned in the specification.

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.

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 process for producing a modified carbon black for rubber reinforcement comprising:

Abstract: A radical-modified polymer having a free radical compound stable in the presence of oxygen at an ordinary temperature at the end of the molecule thereof or in the molecular chain thereof and a polymer composition containing the same.

Abstract: A rubber composition comprising (i) an incompatible polymer blend of at least two diene rubbers selected from rubbers containing a conjugated diene and, optionally, an aromatic vinyl monomer and forming two polymer phases (A) and (B), and (ii) 0.1 to 20 parts by weight, based upon 100 parts by weight of the total polymer component including the block copolymer, of a block copolymer having at least two mutually incompatible blocks (a) and (b), wherein the block (a) is compatible with the polymer phase (A) and incompatible with the polymer phase (B) and the block (b) is compatible with the polymer phase (B) and incompatible with the polymer phase (A), and composed of a conjugated diene and, optionally, an aromatic vinyl monomer, and wherein the molecular weights of the polymers forming the polymer phases (A) and (B) satisfy the specified equations (I) and (II) mentioned in the specification.

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 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 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 polymer having a carbonyl-containing group and a nitrogen-containing 5-membered heterocycle-containing group in side chains, and a composition thereof. The thermoplastic polymer and composition thereof have excellent recycle property in that physical properties do not deteriorate even though formation of crosslinking and dissociation of crosslinking are repeatedly conducted with altering temperature. The thermoplastic polymer and composition thereof are that its crosslinked structure is considerably stable at room temperature, and therefore have considerably high tensile strength. In particular, in the case of bonding to a main chain at 3-position or 4-position of a nitrogen-containing 5-membered heterocycle, intermolecular hydrogen bond is caused, so that a cured product has high mechanical properties.

Abstract: A viscoelasticity improving agent for rubber obtained by reacting an alkyllithium compound with a free radical compound having an isocyanate group in the molecule thereof and existing stably at room temperature in the presence of oxygen and a rubber composition.

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. The polysiloxane is impregnated in an inert powder.