A photohardenable liquid silicone rubber composition for producing a master form

摘要

PROBLEM TO BE SOLVED: To obtain the subject composition capable of giving a cured product bearing specific physical properties through photoirradiation, and thus capable of giving in a simple operation in a short time an impression aster block ena bling a photocurable liquid resin to be cured by rays through the wall surface of an aster block. ;SOLUTION: This liquid silicone rubber composition, which is capable of giving a cured product 20-60 in Shore A hardness and ≥10% in light transmittance when cured to 10mm thickness through photoirradiation, etc., irradiation with ultraviolet rays 200-500nm in wavelength, preferably comprises (A) 100 pts.wt. of an organopolysiloxane essentially comprising an organopolysiloxane of the formula (R is an aliphatic unsaturated bond-free monovalent hydrocarbon or alkoxy; R¹ is an acryloyl-contg. group, vinyloxyalkyl, etc.; (a) and (b) are each a positive number satisfying the relationships: 1.9≤(a)2.4, 0.0003≤(b)≤0.1, and 1.9(a+b)≤2.4) bearing two or more photoreactive groups and having a viscosity of 100-1000,000cP at 25°C and (B) 0.01-5 pts.wt. of a photoinitiator.;COPYRIGHT: (C)1998,JPO