RUBBER COMPOSITION AND STUDLESS TIRE

摘要

Provided are a rubber composition capable of achieving a balanced improvement in performance on ice and snow, fuel economy, abrasion resistance, rubber strength, wet-grip performance, and dry handling stability, and a studless winter tire including the rubber composition. The present invention relates to a rubber composition including a specific conjugated diene polymer obtained by using a polymerization initiator represented by the formula (I) below, a high-cis polybutadiene having a cis microstructure content of not less than 95% by mass, a polyisoprene-based rubber, and a silica having a N2SA of 40-400 m2/g, wherein the rubber composition includes, based on 100% by mass of a rubber component, 1-45% by mass of the conjugated diene polymer, 20-64% by mass of the high-cis polybutadiene, and 35-60% by mass of the polyisoprene-based rubber, and the rubber composition includes 5-150 parts by mass of the silica for each 100 parts by mass of the rubber component.;

主权项

1. A rubber composition, comprising:
a conjugated diene polymer,
a high-cis polybutadiene having a cis microstructure content of not less than 95% by mass,a polyisoprene-based rubber, 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 C1-100 hydrocarbylene group; R12 and R13 each represent an optionally substituted hydrocarbyl group or a trihydrocarbylsilyl group, or R12 and R13 are bonded to each other to form a hydrocarbylene group optionally containing at least one, as a hetero atom, selected from the group consisting of a silicon atom, a nitrogen atom, and an oxygen atom; 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 rubber composition comprises, based on 100% by mass of a rubber component, 1 to 45% by mass of the conjugated diene polymer, 20 to 64% by mass of the high-cis polybutadiene, and 35 to 60% by mass of the polyisoprene-based rubber, and the rubber composition comprises 5 to 150 parts by mass of the silica for each 100 parts by mass of the rubber component.