Patent attributes
The rubber composition of the invention includes a rubber composition which is a silica compounded rubber composition for tire containing 100 parts by weight of a rubber component made of (a) from 20 to 80% by weight of a vinyl-cis-polybutadiene rubber containing 1,2-polybutadiene having a melting point of 170° C. or higher and a high-molecular substance having at least one unsaturated double bond per a repeating unit and comprising at least one member selected from polyisoprene, crystalline polybutadiene having a melting point of not higher than 150° C., liquid polybutadiene and derivatives thereof and (b) from 80 to 20% by weight of a diene-based rubber other than (a); and (c) from 40 to 100 parts by weight of a rubber reinforcing agent containing 40% or more of silica, wherein the 1,2-polybutadiene is dispersed in a short crystalline fiber state and the high-molecular substance is dispersed in a granular state in the cis-polybutadiene rubber which is a matrix component of the subject vinyl-cis-polybutadiene rubber (a); and the short crystalline fiber of the 1,2-polybutadiene is dispersed in particles of the high-molecular substance.
