| abstract |
Photopolymerizable, liquid, storage stable organopolysiloxanes having viscosities of from 60 mPa.s to 2,000 mPa.s at 25 DEG C., are prepared by reacting (i) an alpha , omega -dihydroxydiorganopolysiloxane oil having a viscosity ranging from about 70 to 500 mPa.s at 25 DEG C., with (ii) a silane having the formula Z(G)SiRa(Q)3-a wherein Z is CH2=C(R')-COO- or HS-, and further wherein the symbols R, which may be the same or different, are methyl, ethyl, n-propyl, vinyl or phenyl, R' is hydrogen or methyl, the symbols Q, which may be the same or different, are methoxy, ethoxy, n-propoxy, beta -methoxyethoxy and, when any two are taken together, the divalent radical -O-(CH3)2-C(CH3)2-O-, G is a linear or branched chain alkylene radical having from 1 to 8 carbons, and a is a number ranging from 0 to 2; and with the molar ratio of the hydroxyl functions comprising the oil (i) to the Q radicals comprising the silane (ii) ranging from 0.1 to 0.95. Such organopolysiloxanes are useful, e.g., release coating compositions. |