| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical disk substrate which has excellent strength, moldability, mold parting properties, transferability, and birefringence and is inexpensive. <P>SOLUTION: The optical disk substrate consists of a rubber denatured styrene resin composition (GS resin composition) essentially consisting of a styrene-(meth)acrylate copolymer composed of a styrene monomer (S), (meth) acrylate monomer (M) and vinyl monomer (V) copolymerizable with these monomers and graft copolymer formed by copolymerizing (S), (M) and (V) copolymerizable with these monomers in the presence of a diene rubber elastic body, in which the weight average molecular weight (Mw) of the TFH-soluble component of the GS resin composition is 50,000 to 100,000; the amount of the diene rubber in the GS resin composition is 5 to 15%; the (S) unit is 5 to 35%; the (M) unit it 50 to 90%; the (V) unit copolymerizable therewith is 0 to 10% and the rubber grain size of the GS resin composition is 0.1 to 0.5 μm. <P>COPYRIGHT: (C)2003,JPO |
