RUBBER COMPOSITION, AND RUBBER-MODIFIED STYRENIC RESIN USING THE SAME

PROBLEM TO BE SOLVED: To provide a rubber composition excellent in impact resistance and environmental stress crack resistance, and to provide a rubber-modified styrenic resin using the same.SOLUTION: A rubber composition is blended with 28-80 wt.% of polybutadiene (A) which satisfies on conditions that a cis-1,4-structure in a microstructure is 65-95 mol%, a vinyl-1,2-structure is 4-30 mol%, and a weight average molecular weight is 2×10-10×10, and is produced by a methallocene catalyst, and 72-20 wt.% of polybutadiene (B) satisfying conditions that 5 wt.% styrenic solution viscosity (St-cp) at 25°C is 110-190, Mooney viscosity (ML100°C) is 60 or less and St-cp/ML100°C is 2.6-4.1 so that the total of (A) and (B) is 100 wt.%.SELECTED DRAWING: None 【課題】耐衝撃性と耐環境応力亀裂性に優れるゴム組成物、及びそれを用いたゴム変性スチレン系樹脂を提供する。【解決手段】本発明のゴム組成物は、ミクロ構造中のシス−１，４−構造が６５〜９５モル％、ビニル−１，２−構造が４〜３０モル％、及び重量平均分子量が２×１０５〜１０×１０５の条件を満たし、メタロセン触媒により製造されたポリブタジエン（Ａ）２８〜８０重量％と、２５℃での５重量％スチレン溶液粘度（Ｓｔ−ｃｐ）が１１０〜１９０、ムーニー粘度（ＭＬ１＋４，１００℃）が６０以下、かつ、かつＳｔ−ｃｐ／ＭＬ１＋４，１００℃が２．６〜４．１の条件を満たすポリブタジエン（Ｂ）７２〜２０重量％とが合計で１００重量％となるように配合されたゴム組成物である。【選択図】なし