| 主权项 |
1. An addition-crosslinkable silicone elastomer composition comprising:
(A1) 1-10% by weight of at least one linear organopolysiloxane containing at least 2 SiC-bonded radicals having aliphatic carbon-carbon multiple bonds, wherein the mean molar mass of (A1) is not more than 15,000 g/mol, (A2) 1-20% by weight of at least one linear organopolysiloxane containing at least 2 SiC-bonded radicals having aliphatic carbon-carbon multiple bonds, wherein the mean molar mass of (A2) is at least 40,000 g/mol, (B) 1-40% by weight of at least one organopolysiloxane containing at least three Si-bonded hydrogen atoms per molecule, having a content of Si-bonded hydrogen of from 0.04 to 1.7% by weight and a mean molar mass of not more than 20,000 g/mol, (D) 1-100 ppm (based on the metal) of a hydrosilylation catalyst, (E) 50-99% by weight of at least one branched silicone resin of the general empirical formula (I)
(R33SiO1/2)l(R4R32SiO1/2)t(R4R3SiO)u(R32SiO)p(R4SiO3/2)q(R3SiO3/2)r(SiO4/2)s (I),whereinR3 denotes a linear aliphatic radical,R4 denotes an aliphatically unsaturated radical having a terminal C═C double bond,l, t, u, p, q, r and s denote integers,wherein the following apply:l≧0, t≧0, u≧0, p≧0, q≧0, r≧0 and s≧0; andthe content of aliphatically unsaturated groups in (E) is between 0.2 and 10 mmol/g; and
(E) has a mean molar mass of not more than 105 g/mol,with the proviso that the ratio of the Si—H groups provided by component (B) to the aliphatically unsaturated groups provided by components (A1), (A2) and (E) is between 0.5 and 5 and the ratio of the dynamic viscosity of the silicone elastomer composition at shear rates of 1 s−1 and 100 s−1 and a temperature of 20° C. is not more than 1.2 and after crosslinking exhibits a Shore D hardness of at least 25. |
