EQUILIBRATION OF EPOXY SUBSUBSTITUTED SILOXANES IN PRESENCE OF WATER

摘要

1428549 Equilibration of epoxy-substituted Siloxanes UNION CARBIDE CORP 26 April 1973 19960/73 Heading C3T A process for producing a fluid epoxy-substituted organosiloxane copolymer comprises equilibrating with a basic equilibration catalyst a mixture of at least one cyclic organopolysiloxane and at least one linear siloxane, at least one of the cyclic or linear siloxanes containing epoxyorgano-substituents, which mixture contains up to 1% wt. of an active hydrogen containing compound, i.e. either water or a compound containing the group -Si-OH. Each siloxane to be equilibrated generally contains no more than 80 siloxy units. A hydrocarbon solvent may be used. Suitable basic catalysts are alkali metal-oxides and hydroxides, alkali metal alkoxides and aryloxides, and alkali metal silanolates and siloxanolates, and the quaternary bases : tetraalkylammonium hydroxide, tetralkylphosphonium alkoxides, trialkylhydrazinium silanolate and trialkylguanidinium siloxanolate. In the examples linear epoxy-siloxanes are first prepared by reacting (1) a trimethylsilyl-terminated dimethyl and methyl hydrogen siloxane copolymer fluid with either (a) 3,4-epoxycyclohexylethylene, or (b) 1-allyloxy-2,3-epoxypropane; or by reacting (2) heptamethyltrisiloxane with either (a) 3,4-epoxy-1-butene, or (b) 2,3- epoxy-1-propanol. The linear epoxy siloxanes thus prepared are each equilibrated with a mixture of octamethylcyclotetrasiloxane, hexamethylcyclotrisiloxane and decamethylpentacyclosiloxane, said mixture containing 0À05% wt. of water, using as catalyst tetramethylammonium dimethylsiloxanolate. In a further example the linear epoxysiloxane (la) is equilibrated with the above mixture of cycloorganosiloxanes and the above basic catalyst and any one of the following siloxanes: a mixture of cyclic tetramers and pentamers of formula [CH 2 =CH(CH 3 )SiO] 4-5 ; a cyanopropylmethylsiloxane cyclic mixture; and