Patent ID: 6846852

Claim:
Compositions, which can be crosslinked by radiation to give elastomers or elastomeric coatings, which comprise: (a) high-molecular weight siloxanes with multiple (meth)acrylate functional groups; and (b) reinforcing fillers selected from the group consisting of silicone resins and silicone dioxide fillers, wherein the siloxanes (a) have the general structure: [R 3 SiO 1/2 ] a [(Z) n G—Y m —R 2 SiO 1/2 ] a′ [R 2 SiO 2/2 ] b [(Z) n G—Y m —RSiO 2/2 ] b′ [RSiO 3/2 ] c [SiO 4/2 ] d′ wherein R is a linear or branched, alkyl, alkenyl or aryl radical which may be substituted with halogen atoms, G(Z) n is a (meth)acrylfunctional radical, wherein G is a (n+1) valent radical derived from a hydroxy compound with 3 to 10 carbon atoms, 1 to 6 hydroxy groups, 0 to 1 carboxylic ester groups and 0 to 2 ether linkages, which may optionally be unsaturated or alkoxylated with ethylene oxide, propylene oxide or mixtures thereof and wherein the organic groups bearing the acrylate radical(s) are attached to the siloxane framework by way of Si—C bonds, Y is —OOC—CHR′—CH 2 — or —OOC—CHR′(CH 3 )—, m is 0 or 1, n is 1-6, Z is —OC—CR′═CH 2 and may additionally comprise carboxylic acid radicals free of double bond, R′ is hydrogen or methyl, a is 0-20, a′ is 2-0, b is 800-10000, b′ is 0-40, and c is 0-40, d is 0-40, with the proviso that the polymer contains more than two (meth)acrylate groups; and wherein the silicone resins of component (b) have the general structure: [R 1 3 SiO 1/2 ] x [R 1 2 R 2 SiO 1/2 ] x′ [R 1 SiO 3/2 ] y [R 2 SiO 3/2 ] y′ [SiO 4/2 ] z , wherein R 1 is a monovalent alkyl or alkenyl radical with 1 to 4 carbon atoms, phenyl, hydroxy, methoxy or ethoxy, R 2 is a (meth)acrylated hydroxyalkyl radical with 1 to 4 carbon atoms in the alkyl group, having a average molecular weight of 500 to 100,000, with the proviso that (x+x′)/(y+y′+z) is 0.5 to 1.5 and (y+y′)/z is 0 to 0.4.