Structured, diene rubber-based composition for tire treads contains resin-coated bubbles derived from an additive consisting of resin containing a chemical foaming agent

摘要

A structured rubber composition (I) with microcapsule-shaped bubbles which are coated with resin after vulcanization comprises (i) 100 parts by weight (pts. wt.) diene rubber and (ii) 0.5-20 pts. wt. of a resin with 5-65 wt% of a chemical foaming agent, the resin consisting mainly of a polyolefin which is not co-crosslinkable with the rubber (i). An Independent claim is also included for a method for the production of (I) by mixing a foaming agent-containing resin with a diene rubber, compounding and extruding the mixture at a temperature below the decomposition temperature (Tdec) of the chemical foaming agent, and vulcanizing the mixture at a temperature which is at or above Tdec, causing expansion and foaming with dispersion of resin-coated microcapsular bubbles in the rubber.