Patent ID: 7592412
Filing Date: 2009-09-22
Classification: C08G,C08L,C09D

Abstract:
1. A release coating composition comprising an alkenyl functional polysiloxane (I), consisting of: i) one or more Q units of the formula (SiO ii) from 15 to 995 D units of the formula R iii) M units of the formula R wherein each R a substituent is selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms and an alkynyl group having from 2 to 6 carbon atoms, at least three R a substituents in the branched siloxane being alkenyl or alkynyl units, and each R b substituent is selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, an alkoxy group, an acrylate group and a methacrylate group a silicon hydride functional polysiloxane (II) having the formula where each R is independently selected from a hydrogen atom and a monovalent hydrocarbon group comprising 1 to 20 carbon atoms which is free from aliphatic unsaturation, at least one R being a hydrogen atom, a is an integer from 1 to 18, b is an integer from 2 to 19, a+b is an integer from 3 to 20, each X is an independently selected functional group selected from a halogen atom, an ether group, an alkoxy group, an alkoxyether group, an acyl group, an epoxy group, an amino group, a silyl group, or a -Z-R 4 group, where each Z is independently selected from an oxygen and a divalent hydrocarbon group comprising 2 to 20 carbon atoms, each R 4 group is independently selected from —BR u Y 2−u , —SiR v Y 3−v , or a group described by formula (II): where B refers to boron, each R is as described above, the sum of c+d+e+f+g+h+i+j is at least 2, n is an integer from 0 to 3, o is an integer from 0 to 2, p is an integer from 0 to 1, q is an integer from 0 to 1, r is an integer from 0 to 2, s is an integer from 0 to 2, t is an integer from 0 to 3, u is an integer from 0 to 2, v is an integer from 0 to 3, each Y is an independently selected functional group selected from a halogen atom, an ether group, an alkoxy group, an alkoxyether group, an acyl group, an epoxy group, an amino group, or a silyl group, or a Z-G group, where Z is as described above, each G is a cyclosiloxane described by the formula: where R and X are as described above, k is an integer from 0 to 18, m is an integer from 0 to 18, k+m is an integer from 2 to 20, provided in formula (II) that one of the Y groups is replaced by the Z group bonding the R 4 group to the cyclosiloxane of formula (I), and provided further (a) at least one X group of Formula (I) is a -Z-R 4 group, (b) if Z is a divalent hydrocarbon group, a=1, c=2, e+f+g+h+i+j=0 and d>0, then at least one d unit (i.e. Y 2−o R o SiO 2/2 ) contain a -Z-G group or the c units (ie. Y 3−n R n SiO 1/2 ) have no -Z-G group or at least two -Z-G groups, (c) if Z is a divalent hydrocarbon group, a=1, c=2 and d+e+f+g+h+i +j=0, then the c units (i.e. Y 3−n R n SiO 1/2 ) have no -Z-G group or at least two -Z-G groups, and (d) if g+h+i+j>0 then c+d+e+f>0 and a catalyst (III) comprising a platinum group metal, wherein the alkenyl functional polysiloxane (I) is an alkenyl-terminated polysiloxane prepared by siloxane polycondensation and/or equilibration using a phosphazene base catalyst and that the level of catalyst (III) in the composition is 2-40 parts per million platinum group metal by weight.