Patent ID: 8524842

Claim:
A silicone composition comprising: (A) at least one polyorganosiloxane POS (I) having: a) endgroup siloxyl units of type M=(R) 2 (H)SiO 1/2 in which the R radicals, which may be identical or different, are each an optionally substituted linear or branched C 1 -C 6 alkyl radical and/or a substituted or unsubstituted aryl radical, and b) identical or different siloxyl units of type D=(R 1 ) p (H) q SiO 2/2 in which the R 1 radicals have the same definition as R and p=1 or 2, g=0 or 1 and p+g=2; with the proviso that the polyorganosiloxane POS (I) comprises at least two SiH radicals per molecule; (B) at least one polyorganosiloxane POS (II) having: a) endgroup siloxyl units of type M=(X) s (R 2 ) t SiO 1/2 in which the R 2 radicals have the same definition as R, the X radicals are alkenyl radicals having from 2 to 6 carbon atoms, s=0 or 1, 1=2 or 3 and s+t=3; and b) identical or different siloxyl units of type D=(X) u (R 3 ) v SiO 2/2 in which the R 3 radicals have the same definition as R, the X radicals are alkenyl radicals having from 2 to 6 carbon atoms, u=0 or 1, v=1 or 2 and u+v=2, with the proviso that the polyorganosiloxane POS (II) comprises at least two X radicals per molecule; (C) at least one monofunctional polyorganosiloxane POS (III) which is essentially linear, having less than 2 mol % of siloxyl unit T=RSiO 3/2 , and which comprises, per molecule, one alkenyl radical (X) having from 2 to 6 carbon atoms directly bonded to a silicon atom, the said POS (III) having: a) identical or different endgroup siloxyl units of type M=(X) w (R 4 ) x SiO 1/2 in which the R 4 radicals have the same definition as R, w=0, x=3; and b) at least one siloxyl unit D=(X) y (R 5 ) z SiO 2/2 in which the R 5 radicals have the same definition as R, y=1, z=1, (D) an effective amount of at least one hydrosilylation reaction catalyst; and (E) at least one nonfunctionalized polyorganosiloxane POS (IV) having: a) endgroup siloxyl units of type M=(R 6 ) 3 SiO 1/2 in which the R 6 radicals have the same definition as R, and b) identical or different siloxyl units of type D=(R 7 ) 2 SiO 2/2 in which the R 7 radicals have the same definition as R; with the proviso that the amount of the constituents (A), (B), (C) and (E) is such that the molar ratio r of the hydrogen atoms bonded to silicon to the alkenyl radicals (X) bonded to silicon is 1:1; wherein the composition is crosslinkable into a gel by hydrosilylation and said composition, upon crosslinking, has a viscous modulus, (G″) and an elastic modulus (G′) greater than a comparable composition lacking component (C), POS (III).