METHOD FOR PRODUCING VULCANIZED RUBBER COMPOSITION, VULCANIZED RUBBER COMPOSITION, AND STUDLESS TIRE USING SAME

摘要

This method for producing a vulcanized rubber composition comprises (a) a step for preparing a master batch including a butadiene rubber and silica, (b) a step for preparing a master batch including an isoprene-based rubber and silica, (c) a step for kneading the master batch obtained in (a) and the master batch obtained in (b), and (d) a step for vulcanizing the kneaded product obtained in (c), wherein: the obtained vulcanized rubber composition has a BR phase and an IR phase that are incompatible with one another; the abundance ratio α of silica in a predetermined BR phase satisfies 0.3 ≤ α ≤ 0.7 (formula 1); and the proportion β of the butadiene rubber satisfies 0.4 ≤ β ≤ 0.8 (formula 2). Accordingly, this method can improve on-ice performance and wear resistance in a balanced manner, and can provide: a vulcanized rubber composition that has excellent on-ice performance and wear resistance; and a studless tire using said vulcanized rubber composition as a constituent of a tread.