Provided is a rubber composition that realizes excellent low heat generating properties while maintaining good steering stability when applied to a tire. The rubber composition of the present disclosure contains a rubber component containing a copolymer having a conjugated diene unit and an aromatic vinyl unit, and a filler, where the copolymer is a modified copolymer having a content of the aromatic vinyl unit of less than 10 mass % and modified with a modifier containing a compound represented by the formula (1).

##STR00001##

The present invention relates to the use of N,N′,N″-substituted hexahydro-1,3,5-triazine in the anionic polymerization of conjugated diene monomer and vinylaromatic monomer. Use of this polar additive produces copolymers having both high vinylaromatic and low vinyl contents, while the blockiness of the vinylaromatic unit can be tailored.

The present invention relates to the use of N,N′,N″-substituted hexahydro-1,3,5-triazine in the anionic polymerization of conjugated diene monomer and vinylaromatic monomer. Use of this polar additive produces copolymers having both high vinylaromatic and low vinyl contents, while the blockiness of the vinylaromatic unit can be tailored.

The present disclosure provides a tire having excellent enduring performance. The present disclosure relates to a tire including a tread containing a rubber composition, the rubber composition satisfying the following relationships 1) to 3) when measured within 180 days after vulcanization: 1) Hso/Hsa×100≥95 wherein Hso: hardness at room temperature, Hsa: hardness at room temperature after heat treatment at 80° C. for 168 hours; 2) As/Ts×100≤70 wherein Ts: sulfur content before acetone extraction, As: sulfur content after acetone extraction; and 3) Swell≤330 wherein Swell: toluene swelling index.

The present disclosure provides a tire having excellent enduring performance. The present disclosure relates to a tire including a tread containing a rubber composition, the rubber composition satisfying the following relationships 1) to 3) when measured within 180 days after vulcanization: 1) Hso/Hsa×100≥95 wherein Hso: hardness at room temperature, Hsa: hardness at room temperature after heat treatment at 80° C. for 168 hours; 2) As/Ts×100≤70 wherein Ts: sulfur content before acetone extraction, As: sulfur content after acetone extraction; and 3) Swell≤330 wherein Swell: toluene swelling index.

Disclosed herein are styrene butadiene rubber latex compositions with high solids content and methods for making and using these compositions. The method for making the styrene butadiene rubber latex compositions can include mixing a seed, a styrene, an initiator, a base, a surfactant, and a solvent; adding a first portion of 1,3-butadiene to make a first reaction mixture; heating the first reaction mixture for a first reaction time to make a first styrene butadiene rubber latex; mixing the first styrene butadiene rubber latex, a styrene, a base, an initiator, a surfactant, and a solvent; adding a second portion of 1,3-butadiene to make a second reaction mixture; and heating the second reaction mixture for a second reaction time to make a second styrene butadiene rubber latex, where the second styrene butadiene rubber latex has a solids content higher than that of the first styrene butadiene rubber latex.

Disclosed herein are styrene butadiene rubber latex compositions with high solids content and methods for making and using these compositions. The method for making the styrene butadiene rubber latex compositions can include mixing a seed, a styrene, an initiator, a base, a surfactant, and a solvent; adding a first portion of 1,3-butadiene to make a first reaction mixture; heating the first reaction mixture for a first reaction time to make a first styrene butadiene rubber latex; mixing the first styrene butadiene rubber latex, a styrene, a base, an initiator, a surfactant, and a solvent; adding a second portion of 1,3-butadiene to make a second reaction mixture; and heating the second reaction mixture for a second reaction time to make a second styrene butadiene rubber latex, where the second styrene butadiene rubber latex has a solids content higher than that of the first styrene butadiene rubber latex.

An object of the present invention is to provide a conveyor belt rubber composition having excellent wear resistance and gouging resistance, a method for producing the conveyor belt rubber composition, a conveyor belt formed using the conveyor belt rubber composition, and a belt conveyor equipped with the conveyor belt. The present invention relates to a conveyor belt rubber composition containing a diene rubber containing less than 50 mass % of an aromatic vinyl-conjugated diene copolymer, wherein the aromatic vinyl-conjugated diene copolymer has a content of repeating units derived from an aromatic vinyl of 20 mass % or less, and a proportion of a vinyl structure in repeating units derived from a conjugated diene of 8 mol % or less.

An object of the present invention is to provide a conveyor belt rubber composition having excellent wear resistance and gouging resistance, a method for producing the conveyor belt rubber composition, a conveyor belt formed using the conveyor belt rubber composition, and a belt conveyor equipped with the conveyor belt. The present invention relates to a conveyor belt rubber composition containing a diene rubber containing less than 50 mass % of an aromatic vinyl-conjugated diene copolymer, wherein the aromatic vinyl-conjugated diene copolymer has a content of repeating units derived from an aromatic vinyl of 20 mass % or less, and a proportion of a vinyl structure in repeating units derived from a conjugated diene of 8 mol % or less.

To provide a method for producing a multicomponent copolymer with which a multicomponent copolymer having excellent rupture strength can be obtained, and a multicomponent copolymer, a rubber composition and a tire having excellent rupture strength. The method is a method for producing a multicomponent copolymer having a conjugated diene unit, a non-conjugated olefin unit and an aromatic vinyl unit, comprising adding a conjugated diene compound in divided portions into a reactor containing a catalyst and at least one selected from the group consisting of a non-conjugated olefin compound and an aromatic vinyl compound. The multicomponent copolymer is obtained with the production method. The rubber composition comprises the multicomponent copolymer as a rubber component. The tire uses the rubber composition.