Composite membrane and process for the production thereof.

摘要

The prodn. of composite membranes comprises spreading a soln. of a polymer (I) in a volatile solvent on water. Allowing the solvent to evaporate, crosslinking the polymer and transferring the film obtd. to a supporting membrane. Also claimed is a composite membrane with polymer layer(s) on a porous base membrane, obtd. by this process. (I) is a polysiloxane which is pref. crosslinked via OH gps. on the polymer, with the aid of a bi-, tri- or tetra-functional silane with hydrolysable SiO- gps. as crosslinker (II), pref. triacetoxy-methyl-silane (TACMS), in the presence of a catalyst, pref. a tin salt. Alternatively, (I) may be a polymer contg. olefinic double bonds, which is crosslinked by irradiation. Pref. polymer layer is a protective layer of polysiloxane, crosslinked via OH gps. to a structure contg. units of formula Si(O-)4, R-Si(O-)3 or RR<1>Si(O-)2 (with R, R<1> = alkyl, phenyl or vinyl), or a silicone which is crosslinked by irradiation.