The present invention relates to a hydrogenated styrene-conjugated diene-styrene copolymer having excellent toughness, heat distortion temperature, and moldability, a production process therefor, and an optical material, etc. employing the copolymer. The styrene-conjugated diene-styrene block copolymer of the present invention is a hydrogenated styrene-conjugated diene-styrene block copolymer obtained by hydrogenating a styrene-conjugated diene-styrene block copolymer comprising mainly styrene polymer blocks and a conjugated diene polymer block, wherein (A) the hydrogenated styrene polymer block/hydrogenated conjugated diene polymer block ratio by weight is 75/25 to 97/3, (B) the degree of hydrogenation is at least 90%, (C) the number-average molecular weight obtained by a GPC method is 30,000 to 200,000 g/mol, and (D) the hydrogenated styrene-conjugated diene-styrene block copolymer contains 1 to 20 wt % of a high molecular weight component having a molecular weight that is at least three times the number-average molecular weight obtained by the GPC method.
本发明涉及一种具有优异韧性、耐热变形温度和可塑性的氢化
苯乙烯-共轭二烯-
苯乙烯嵌段共聚物,以及其生产工艺和采用该共聚物的光学材料等。本发明的
苯乙烯-共轭二烯-
苯乙烯嵌段共聚物是一种氢化
苯乙烯-共轭二烯-
苯乙烯嵌段共聚物,其通过氢化主要包含
苯乙烯聚合物块和共轭二烯聚合物块的
苯乙烯-共轭二烯-
苯乙烯嵌段共聚物得到,其中(A)氢化
苯乙烯聚合物块/氢化共轭二烯聚合物块的重量比为75/25至97/3,(B)氢化程度至少为90%,(C)通过
GPC方法得到的数均分子量为30,000至200,000 g/mol,(D)氢化
苯乙烯-共轭二烯-
苯乙烯嵌段共聚物含有1至20重量%的高分子量组分,其分子量至少是通过
GPC方法得到的数均分子量的三倍。