Hydrogenated vinyl aromatic hydrocarbon polymer composition and optical disc substrate

摘要

A hydrogenated vinyl aromatic hydrocarbon polymer comprising: (a) 5 to 90% by weight of a vinyl aromatic hydrogenated polymer (A) obtainable by hydrogenating a hydrocarbon-conjugated diene block copolymer in such an amount that substantially all the double bonds derived from the conjugated diene bonds and from 60 mol% to 80 mol% of the double bonds in the aromatic rings have been hydrogenated, the content of the conjugated diene polymer units in the block copolymer being from 1 to 50 wt%; and (b) 10 to 95% by weight of a hydrogenated polymer (B) obtainable by hydrogenating a vinyl aromatic hydrocarbon polymer in such an amount that from 60 mol% to 80 mol% of the double bonds in the aromatic rings have been hydrogenated. c