Patent ID: 7374819
Filing Date: 2008-05-20
Classification: C08J,C09D,C09J,Y10T

Abstract:
1. A release film comprising a plastic film substrate, a first layer provided on at least one side of the substrate, and a second layer provided on the first layer, characterized in that the first layer is prepared from a first silicone composition comprising the following components (A-1), (B-1), (C-1), and (D-1): (A-1) 100 parts by weight of an organopolysiloxane(I) represented by the following formula (1), wherein R 1 is an alkenyl group, R 2 may be the same with or different from each other and is a monovalent hydrocarbon group except an alkenyl group, R 3 is a hydrogen atom or an alkyl group, m and n are positive numbers, p is zero or a positive number with 0.6≦(n+p)/m≦1.5, and 0≦p/(n+p)≦0.05, and m, n and p are selected so that the organopolysiloxane (I) has a viscosity of from 5 to 100 mPa.s at 25 degrees C., (B-1) 10 to 100 parts by weight of an organopolysiloxane(II) represented by the following formula (2), wherein R 4 may be the same with or different from each other and is a monovalent hydrocarbon group with at least two R 4 's in a molecule being alkenyl groups, t is a number ranging from 0 to 15, each of q, r, and s is zero or a positive number, and t, q, r, and s are selected so that a 30 wt % of the organopolysiloxane(II) solution in toluene has a viscosity of from 100 to 20,000 mpa.s at 25 degrees C., (C-1) 30 to 100 parts by weight of an organohydrogenpolysiloxane having at least two SiH groups in a molecule, and (D-1) a catalytic amount of a compound of a platinum group metal; and the second layer is prepared from a second silicone composition comprising the following components (A-2), (C-2) and (D-2): (A-2) 100 parts by weight of a polyorganosiloxane having alkenyl groups in an amount of at least two per molecule and from 0.02 to 0.20 mole per 10 g of the polyorganosiloxane, and a viscosity of from 50 to 100,000 mPa.s at 25 degrees C., (C-2) an organohydrogenpolysiloxane having at least two SiH groups per molecule in such an amount that a molar amount of the SiH group in the component (C-2) is 0.5 to 5 times that of the alkenyl group contained in the component (A-2), and (D-2) a catalytic amount of a compound of a platinum group metal.