| 摘要 |
<p>A molding material having a metal content of 5ppm or below can be obtained by producing an A-B-A type block copolymer wherein A is a polymer block composed of units of an aromatic vinyl monomer and B is a polymer block composed of units of a conjugated diene monomer, hydrogenating the aromatic rings of the block copolymer resulting from the aromatic vinyl monomer and the unsaturated bonds thereof resulting from the conjugated diene monomer to a degree of at least 90 mole % to obtain a polymer having a weight-average molecular weight of 50000 to 300000 and containing 10 to 60 wt% of hydrogenated conjugated diene monomer units based on the whole of the polymer, and purifying the polymer. This material can give through molding electrical insulators which are lowered in dielectric constant and dielectric loss tangent and are excellent in impact strength and in plate adhesion and smoothness.</p> |
