	US 7,592,412 B2
	Silicone release coating compositions
Stephen Edward Cray, Sully (United Kingdom); Robert Alan Ekeland, Midland, Mich. (US); Peter Cheshire Hupfield, Trevaughan (United Kingdom); Sarah O'Hare, Nr. Barry (United Kingdom); David A. Rich, Barry (United Kingdom); and Marc Thibaut, Chapelle-Lez-Herlaimont (Belgium)
Assigned to Dow Corning Corporation, Midland, Mich. (US)
Appl. No. 10/555,509 PCT Filed Jul. 02, 2004, PCT No. PCT/EP2004/007806 § 371(c)(1), (2), (4) Date Aug. 06, 2006, PCT Pub. No. WO2005/005544, PCT Pub. Date Jan. 20, 2005.
Claims priority of application No. 0316162.7 (GB), filed on Jul. 10, 2003.
Prior Publication US 2007/0167563 A1, Jul. 19, 2007
Int. Cl. C08G 77/04 (2006.01); C08G 77/08 (2006.01); C08G 77/12 (2006.01); C08G 77/20 (2006.01); C07F 9/06 (2006.01)

U.S. Cl. 528—21 [528/23; 528/31; 528/32; 528/37; 564/12]

5 Claims

1. A release coating composition comprising an alkenyl functional polysiloxane (I), consisting of:

i) one or more Q units of the formula (SiO_4/2),

ii) from 15 to 995 D units of the formula R^b₂SiO_2/2, and

iii) M units of the formula R^aR^b₂SiO_1/2,

wherein each R^asubstituent 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^asubstituents in the branched siloxane being alkenyl or alkynyl units, and each R^bsubstituent 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-R⁴group, where each Z is independently selected from an oxygen and a divalent hydrocarbon group comprising 2 to 20 carbon atoms, each R⁴group is independently selected from —BR_uY_2−u, —SiR_vY_3−v, or a group described by formula (II):

(Y_3−nR_nSiO_1/2)_c(Y_2−oR_oSiO_2/2)_d(Y_1−pR_pSiO_3/2)_e(SiO_4/2)_f(CR_qY_1−q)_g(CR_rY_2−r)_h(OCR_sY_2−s)_i(CR_tY_3−t)_j

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 R⁴group to the cyclosiloxane of formula (I), and provided further (a) at least one X group of Formula (I) is a -Z-R⁴group, (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−oR_oSiO_2/2) contain a -Z-G group or the c units (ie. Y_3−nR_nSiO_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−nR_nSiO_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>0and 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.