Alkenyl-substd. siloxane] copolymer mfd. easily for min. isomerisation

摘要

Siloxane copolymers (I) contg. alkenyl gps. are claimed, which can be prepd. by: (1) reacting an organic cpd. contg. at least 3 aliphatic double bonds, of the formula (II) with an organosiloxane (III) with terminal Si-bound H atoms and a b.pt. /} 250 deg C in the presence of a catalyst (IV) promoting addn. of Si-bound H to aliphatic double bonds and removing excess (III) by distn., using a ratio of Si-bound H in (III) to aliphatic double bonds in (II) of 1.5-20; (2) reacting the resultant hydrocarbon-siloxane copolymer (V) contg. Si-bound H with an alpha ,w-diene (VI) in the presence of (IV) at a ratio of aliphatic double bonds in (VI) to Si-bound H in (V) of 2.0-20; and opt. (3) equilibrating the resultant siloxane copolymer (VII) contg. alkenyl gps. with an organopolysiloxane (VIII) of linear OH-terminated organopolysiloxane, branched organopolysiloxane opt. contg. OH gps., cyclic organopolysiloxane and copolymers of diorganosiloxane and monoorganosiloxane units. R<2>(CR<3>=CH2)x (II) R<2> = a tri- or tetra-valent 1-25 C hydrocarbon gp. or tri- or tetravalent silane gp.; R<3> = H or 1-6 C alkyl; and x = 3 or 4. Also claimed are: (a) curable compsns. contg. (I); (b) siloxane copolymers (V) per se; and (c) methods of producing (I) and (V).