Patent ID: 7247674
Filing Date: 2007-07-24
Classification: B32B,C08F,C08L,Y10T

Abstract:
1. A polymer composition, comprising: a block copolymer (a) comprising a polymer block A, which comprises mainly an α-methylstyrene, and a hydrogenated or unhydrogenated polymer block B, which comprises a conjugated diene, wherein block copolymer (a) has a weight average molecular weight of 30,000 to 200,000; an acrylic resin (b) which is a homopolymer of methyl methacrylate or a copolymer comprising methyl methacrylate as the major component and copolymerizable monomers selected from the group consisting of (meth)acrylic acid, metal salts of (meth)acrylic acid, (meth)acrylic acid esters, vinyl acetate, aromatic vinyl compounds, maleic anhydride, maleimide compounds and mixtures thereof; and optionally, a softener (c); and wherein proportions (by mass) of respective components in the polymer composition are such that each of the following relationships (1) and (2) holds: wherein Wa, Wb, and Wc represent the amounts (by mass) of the block copolymer (a), the acrylic resin (b) and the softener (c), respectively, and wherein the polymer composition has a morphology in which the block copolymer (a) forms a continuous phase (matrix) and the acrylic resin (b) forms particles having an average particle size of 0.2 μm or less, that are dispersed throughout the continuous phase, forming sea-island structures.