Modified acrylonitrile polymer containing semipermeable membranes

Claim 1

A semipermeable membrane of an acrylonitrile polymer which is either polyacrylonitrile or a copolymer of acrylonitrile with an ethylenically unsaturated monomer selected from the group consisting of vinyl acetate, a vinyl ether, vinyl pyridine, vinyl chloride, styrene, butadiene, (meth)acrylic acid or a (meth)acrylate, maleic anhydride, 2-aminoethyl methacrylate, an allyl compound, or terpolymers or tetrapolymers based on acrylonitrile, or mixtures thereof wherein the acrylonitrile content of the copolymer, terpolymer or terapolymer is at least 5% by weight, said polymer having been chemically modified by reaction with (a) hydroxylamine and (b) a polyfunctional ionic colourless cyclic carbonic acid imide halide containing at least two functional groups capable of reacting with amidoxine groups, said imide halides being selected from the group consisting of s-triazines containing at least two halogen atoms bonded to carbon atoms and primary condensation products thereof, pyrimidines having at least two reactive halogen atoms, halogen pyrimidine carboxylic acid halides, 2,3-dihalogenoquinoxaline-, 2,3-dihalogeno-quinazoline or 2,3-dihalogeno-phthalazinecarboxylic acid halides or sulfonic acid halides, 2-halogeno benzthiazole- or 2-halogenobenzooxazole-carboxylic acid halides or sulfonic acid halides and halogeno-6-pyridazonyl-1-alkanoyl halides and halogeno-6-pyridazonyl-1-benzoyl halides or a combination of polyfunctional anionic and cationic cyclic carbonic acid imide halides capable of reacting with amidoxine groups the cationic compounds being selected from ammonium dichlorotriazinyl compounds and ammonium trichloropyrimidyl compounds and the anionic compounds being selected from dichlorotriazinyl compounds or 2,4,5-trichloropyrimidyl compounds which contain carboxylic or sulfonic acid groups.