PROBLEM TO BE SOLVED: To provide a rubber stopper for medical use, which has excellent needle penetration characteristics, while exhibiting good liquid leakage sealing performance, good sterilization stability or the like.SOLUTION: This invention relates to a rubber stopper for medical use which is obtained by molding a resin composition which contains a component (C) composed of a polyolefin resin in 1-45 wt.% to 100 wt.% of the total of a component (A) composed of a block copolymer having a polymer block P mainly formed of a vinyl aromatic compound and a polymer block Q mainly formed of a conjugated diene and/or a hydrogenated block copolymer in 5-95 wt.% and a component (B) composed of a softening agent for hydrocarbon-based rubbers in 5-95 wt.% and which has at least one or more peaks and/or peak shoulders within the molecular weight ranges of 250,000-350,000 and 100,000-150,000, respectively.COPYRIGHT: (C)2012,JPO&INPIT【課題】 針刺し特性に優れ、かつ液漏れシール性及び滅菌安定性等が良好な医療用ゴム栓を提供する。【解決手段】 成分(A):ビニル芳香族化合物を主体とする重合体ブロックPと、共役ジエンを主体とする重合体ブロックQを有するブロック共重合体及び/または水添ブロック共重合体 5~95重量%と、成分(B):炭化水素系ゴム用軟化剤 5~95重量%との合計100重量%に対して、成分(C):ポリオレフィン系樹脂 1~45重量%を含有してなる樹脂組成物を成形して得られ、かつ分子量:250,000~350,000と、100,000~150,000の範囲にそれぞれ少なくとも一つ以上のピーク及び/またはピークショルダーを有する医療用ゴム栓。【選択図】 なし
