Rubber composition, and pneumatic tire

摘要

Provided are a rubber composition achieving balanced improvement in processability, fuel economy, rubber strength, abrasion resistance, wet-grip performance, and handling stability, and a pneumatic tire including the composition. The rubber composition includes, per 100% by mass of a rubber component, at least 35% by mass of SR, the composition including a conjugated diene polymer and a silica having N2SA of 40-400 m2/g, the polymer being obtained by polymerizing a monomer component including a conjugated diene compound and a silicon-containing vinyl compound using a polymerization initiator of formula (I):;
to produce a copolymer, and reacting a compound containing nitrogen and/or silicon atoms with an active terminal of the copolymer, wherein the amount of the diene polymer is 1-90% by mass and the amount of polyisoprene-based rubber is 0-40% by mass, each per 100% by mass of the rubber component, and the amount of the silica is 10-150 parts by mass per 100 parts by mass of the rubber component.

主权项

1. A rubber composition, comprising, based on 100% by mass of a rubber component, not less than 35% by mass of styrene-butadiene rubber, the rubber composition comprising
a conjugated diene polymer, and a silica having a nitrogen adsorption specific surface area of 40 to 400 m2/g, the conjugated diene polymer being obtained by polymerizing a monomer component including a conjugated diene compound and a silicon-containing vinyl compound in the presence of a polymerization initiator represented by the following formula (I): wherein i represents 0 or 1; R11 represents a C7-80 hydrocarbylene group; R12 and R13 each are a hydrocarbyl group, or R12 and R13 are joined together to form a hydrocarbylene group; and M represents an alkali metal atom, to produce a copolymer, and then reacting a compound containing at least one of a nitrogen atom and a silicon atom with an active terminal of the copolymer, wherein the silicon-containing vinyl compound is a compound represented by the following formula (II): wherein m represents 0; X1, X2 and X3 each represent a group represented by the following formula (IIa), or a hydrocarbyl group; at least one of X1, X2 and X3 is a group represented by the following formula (IIa), wherein R22 and R23 each are an alkyl group, wherein the compound containing at least one of a nitrogen atom and a silicon atom is at least one selected from the group consisting of a compound represented by the following formula (IIIb), a compound represented by the following formula (IIId), a compound represented by the following formula (IV), a tris[(alkoxysilyl)alkyl] isocyanurate compound, and an N,N-dialkyl-substituted carboxylic acid amide dialkyl acetal compound, wherein R32 represents a hydrocarbyl group; and R36 represents a hydrocarbylene group, or a group in which a hydrocarbylene group and a group represented by —NR35— are bonded, where R35 represents a hydrocarbyl group or a hydrogen atom, where in R31 and R32 each represents a hydrocarbyl group; R37 represents a hydrocarbylene group; A represents an oxygen atom or —NR35— wherein R35 represents a hydrocarbyl group or a hydrogen atom; and R34 represents a hydrocarbyl group or a hydrogen atom, wherein R41 represents a hydrocarbyl group; R42 and R43 each represent a hydrocarbyl group or a hydrocarbyloxy group; R44 and R45 each represents a hydro carbyl group; and j represents an integer of 1 to 5, wherein an amount of the conjugated diene polymer is 25 to 75% by mass and an amount of a polyisoprene-based rubber is 0 to 40% by mass, each based on 100% by mass of the rubber component, and an amount of the silica is 10 to 150 parts by mass for each 100 parts by mass of the rubber component.