Patent ID: 7148306

Claim:
An addition-crosslinkable, injection moldable silicone composition comprising: an ethylenically unsaturated organopolysiloxane component comprising (A) and (B): (A) 100 parts by weight of an α,ω-terminal alkenyl-functional diorganopolysiloxane having a viscosity determined at 25° C. of from 300,000 to 700,000 mPas and comprising 2 units of the formula (1) [R 2 R 1 SiO 1/2 ] (1), units of the formula (2) [R 2 SiO 2/2 ] (2), and from 0 to 0.1 mol % of units of the formula (3) [RR 1 SiO 2/2 ] (3), where, in the formulae (1) to (3), R are identical or different monovalent, unsubstituted or halogen- or cyano-substituted, SiC-bonded C 1 –C 18 -hydrocarbon radicals which are free of aliphatic carbon-carbon multiple bonds and R 1 are identical or different monovalent, unsubstituted or halogen- or cyano-substituted C 1 –C 10 -alkenyl groups which are bound to the silicon either directly or via a divalent organic group, (B) from 2 to 100 parts by weight of a diorganopolysiloxane containing alkenyl-on-chain vinyl units and having a viscosity determined at 25° C. of 20,000 mPas to 40,000 mPas, and comprising units of the formula (2), from 0.5 to 20 mol % of units of the formula (3), and 2 units of the formula (1) and/or units of the formula (4), [R 3 SiO 1/2 ] (4), (C) an SiH-functional crosslinker whose composition corresponds to the average formula (5), H a R 2 b SiO (4-a-b)/2 (5), where R 2 is defined as for R and a and b are nonnegative integers, with the provisos that 0.5<(a+b)<3.0 and 0<a<2 and that at least two hydrogen atoms bound to silicon are present per molecule, and (D) a hydrosilylation catalyst.