Crosslinkable compositions possibly comprising MQ silicone resins

A description is given of novel crosslinkable compositions comprising (A1) linear organopolysiloxanes containing aliphatically unsaturated hydrocarbon radicals, of the general formula R1aR3-aSiO(R2SiO)c[R2Si-Y-SiR2O(R2SiO)c]dSiR3-bR1b (I) where R can be identical or different and is a monovalent, unsubstituted or halogenated hydrocarbon radical which is free from terminal aliphatic carbon-carbon multiple bonds, R1 is a monovalent aliphatically unsaturated hydro-carbon radical, Y is a divalent organic radical which is free from terminal aliphatic carbon-carbon multiple bonds, a is 0 or 1, b is 0 or 1, and the sum a+b per molecule is 1 or 2, (C) is an integer from 1 to 1000 and d is 0 or an integer from 1 to 10, and, if desired, (A2) MQ silicone resins which are soluble in (A1), with the proviso that without the use of MQ silicone resins (A2) the sum a+b in formula (I) is on average from 1.3 to 1.9, and that with the use of MQ silicone resins (A2) the sum a+b in formula (I) is on average from 1.0 to 1.9, (B) organosilicon compounds containing Si-bonded hydrogen atoms, c catalysts which promote the addition of Si-bonded hydrogen onto aliphatic multiple bond, and, if desired, (D) agents which retard the addition of Si-bonded hydrogen onto aliphatic multiple bond at room temperature.