PURPOSE: To obtain the title base plate excellent in e.g., surface hardeness, by photocuring, to a specified shape, a composition produced by incorporating a specified amount of a self-scission-type photopolymerization initiator in a composition comprising a specific polymerizable compound and photopolymerizable (meth)acrylate monomer, etc.
CONSTITUTION: (I) a composition comprising (A) pref. 5W50wt.% of a polymerizable compound of the formula (R1 is H or CH3; R2 is H, 1W6C alkyl, etc.) and (B) pref. 50W80wt.% of at least one kind of compound selected from (meth)acrylate monomers, vinyl group-contg. monomers each photopolymerizable with the component A is incorporated with (II) 0.5W5wt.%, based on the composition I, of a self-scission-type photopolymerization initiator to produce a composition with a viscosity of ≤800cp (at 25°C). This composition is injected, pref. between a transparent plate and stamper with such integral as to be designed to keep a desired level by spacer, followed by ultraviolet irradiation to effect photocuring, thus obtaining the objective optical disc base plate little in optical strain and warpage due to moisture absorption, excellent in heat resistance, mechanical strength, etc.
Horie, Takahiro
Abe, Masami
Aizawa, Teruki
Ishibashi, Takehiko
Yokono, Haruki
