Abstract: Provided is a pneumatic tire which prevents accumulation of static electricity during travelling, which inhibits the tire from rising in an electric resistance with the passage of time, and which is reduced in a rolling resistance of the tire and excellent in durability thereof. In the pneumatic tire described above, a conductive rubber is arranged for a ply coating rubber of one surface, and a non-conductive rubber is arranged for the ply coating rubber of the other surface; assuming that the respective thicknesses thereof are T1 and T2, a carcass ply has a ply in which T1/T2 satisfies 0.2?T1/T2?0.9; and the conductive ply coating rubber is arranged at a tread side, and the non-conductive ply coating rubber is arranged at an inner liner side.

Abstract: As an additive composition capable of improving the processability, the low loss property and the breaking resistance of a silica compounded rubber composition, and a rubber composition excellent in processability, low loss property and breaking resistance, this disclosure provides an additive composition for silica compounded rubber composition comprising a glycerin fatty acid ester, wherein: the glycerin fatty acid ester is an ester of a glycerin and two or more fatty acids, a fatty acid component which is the most among the two or more fatty acids constituting the glycerin fatty acid ester being 10 to 90 mass % of all fatty acids; and a monoester component is contained in an amount of 50 to 100 mass % in the glycerin fatty acid ester, and provides a rubber composition comprising a diene based rubber, a silica, and the additive composition for silica compounded rubber composition.

Abstract: Provided is a pneumatic tire in which an electric resistance can be reduced without adversely affecting other performances such as tire durability or manufacturing processes even when low loss of a rubber member of the tire is attempted. The pneumatic tire includes a belt layer 2 provided at an outer side of a crown portion of a carcass 1 in a tire radial direction, and a rubber chafer 4 is provided at an outer surface of a bead portion in a tire width direction.

Abstract: Provided is a rubber composition containing a high stratified or tabular clay mineral content, wherein the dispersion of the stratified or tabular clay minerals is improved, thus reducing air permeability and improving flex resistance. Also provided is a tire using the rubber composition. An example of the rubber composition is a rubber composition containing a rubber component (A), a stratified or tabular clay mineral (B), and a glycerin fatty acid ester composition (C).

Abstract: As an additive composition capable of improving the processability, the low loss property and the breaking resistance of a silica compounded rubber composition, and a rubber composition excellent in processability, low loss property and breaking resistance, this disclosure provides an additive composition for silica compounded rubber composition comprising a glycerin fatty acid ester, wherein: the glycerin fatty acid ester is an ester of a glycerin and two or more fatty acids, a fatty acid component which is the most among the two or more fatty acids constituting the glycerin fatty acid ester being 10 to 90 mass % of all fatty acids; and a monoester component is contained in an amount of 50 to 100 mass % in the glycerin fatty acid ester, and provides a rubber composition comprising a diene based rubber, a silica, and the additive composition for silica compounded rubber composition.

Abstract: This disclosure provides a rubber composition for tire obtainable by a method for producing a rubber composition comprising: (a) preparing a preliminary composition by preparing a first mixture containing all of or a part of a diene based rubber (A), a silica (B), a silane coupling agent (C) and an activator (D), and containing a glycerin fatty acid ester (E), and kneading the first mixture; and (b) preparing the rubber composition by adding a vulcanizing agent (t,F) into the preliminary composition to prepare a second mixture, and kneading the second mixture, wherein: the glycerin fatty acid ester (E) is an ester of a glycerin and two or more fatty acids, a fatty acid component which is the most among the two or more fatty acids constituting the glycerin fatty acid ester being 10 to 90 mass % of all the fatty acids.

Abstract: The present invention provides a rubber composition obtained by compounding a rubber component (A) containing a copolymer of a conjugated diene compound and an aromatic vinyl compound, a filler containing an inorganic filler (B), a silane coupling agent (C), and at least one accelerator (D) selected from the group consisting of zinc dithiophosphates represented by the general formula (1), being good in the processability in an unvulcanized state, and having a low-heat-generation property and a low abrasion property: wherein, R20's are each independently hydrogen or a monovalent hydrocarbon group, and at least one of R20's is a substituted or unsubstituted linear alkyl group having from 7 to 18 carbon atoms, a substituted or unsubstituted branched-chain alkyl group having from 7 to 18 carbon atoms, or a substituted or unsubstituted cycloalkyl group having from 7 to 18 carbon atoms.

Abstract: Rubber composition which improves dispersibility of silica and enhances processability by reducing viscosity of an unvulcanized rubber and which suppresses rubber scorching, inhibits shrinkage without delaying a vulcanization rate and improves a heat resistance, and a tire prepared by using the above rubber composition. Rubber composition prepared by blending at least one rubber component selected from a natural rubber and/or a diene base synthetic rubber with silica and a glycerin fatty acid ester composition, wherein a blend amount of the glycerin fatty acid ester composition is 0.5 to 15 parts by mass based on 100 parts by mass of the rubber component; the fatty acid has 8 to 28 carbon atoms; the glycerin fatty acid ester composition contains glycerin fatty acid monoester and glycerin fatty acid diester; and a content of the glycerin fatty acid monoester in the glycerin fatty acid ester composition is 85% by mass or less.

Abstract: Provided is a rubber composition containing a high layered or sheet clay mineral content, wherein the dispersion of the stratified or tabular clay minerals is improved, thus reducing air permeability and improving flex resistance. Also provided is a tire using said rubber composition. An example of the aforementioned rubber composition is a rubber composition containing a rubber component (A), a layered or sheet clay mineral (B), and a glycerin fatty acid ester composition (C).

Abstract: Provide are a rubber composition which improves a dispersibility of silica and enhances a processability by reducing a viscosity of an unvulcanized rubber and which suppresses rubber scorching, inhibits shrinkage without delaying a vulcanization rate and improves a heat resistance, and a tire prepared by using the above rubber composition. The rubber composition described above includes a rubber composition prepared by blending at least one rubber component selected from a natural rubber and/or a diene base synthetic rubber with silica and a glycerin fatty acid ester composition, wherein a blend amount of the glycerin fatty acid ester composition is 0.5 to 15 parts by mass based on 100 parts by mass of the rubber component; the fatty acid has 8 to 28 carbon atoms; the glycerin fatty acid ester composition contains glycerin fatty acid monoester and glycerin fatty acid diester; and a content of the glycerin fatty acid monoester in the glycerin fatty acid ester composition is 85% by mass or less.

Abstract: The natural rubber of the present invention is obtained by gelatinizing or multi-coupling a natural rubber latex or a natural rubber and comprises 15% by mass or more of a high molecular weight component, P1, having a molecular weight of 5,000,000 to 50,000,000 and 40% by mass or less of an ultrahigh molecular weight component, P2, having a molecular weight of exceeding 50,000,000, and the relation between mass % of P1 and mass % of P2 is 1.5×mass % of P1?mass % of P2, each measured by the following measuring method, wherein a measuring method for a rubber molecular weight is measured by means of a field flow fractionation equipment with a multi-angle light scattering detector for a soluble part of a centrifuged rubber solution at a centrifugal acceleration of 10,000 to 1,000,000 G.

Abstract: The present invention provides a modified diene rubber which can be produced economically and improve low-loss properties and wear resistance of a rubber composition made therefrom, as compared with the conventional modified diene rubber. The present invention further provides: a method of producing the modified diene rubber; a rubber composition using the modified diene rubber; and a tire using the rubber composition. Specifically, the present invention provides: a modified diene rubber, produced by first oxidizing diene rubber latex and then adding a polar group-including hydrazide compound to a terminal end of a molecular chain of the diene rubber; a rubber composition, comprising the modified diene rubber; and a tire, comprising a tire member made of the rubber composition.

Abstract: The present invention provides a modified diene rubber which can be produced economically and improve low-loss properties and wear resistance of a rubber composition made therefrom, as compared with the conventional modified diene rubber. The present invention further provides: a method of producing the modified diene rubber; a rubber composition using the modified diene rubber; and a tire using the rubber composition. Specifically, the present invention provides: a modified diene rubber, produced by first oxidizing diene rubber latex and then adding a polar group-including hydrazide compound to a terminal end of a molecular chain of the diene rubber; a rubber composition, comprising the modified diene rubber; and a tire, comprising a tire member made of the rubber composition.

Abstract: This invention provides a modified natural rubber producible at a lower cost than the conventional techniques and capable of improving the low loss factor, wear resistance and fracture characteristics of the rubber composition using the modified natural rubber as the rubber component in the rubber composition, and a method for producing the modified natural rubber. This invention provides a modified natural rubber formed by adding a hydrazide compound having a polar group to at least one natural rubber raw material selected from the group consisting of a natural rubber, a coagulated natural rubber latex and a natural rubber cup lump, a rubber composition using the modified natural rubber, and a tire using the rubber composition in any tire member.