Cation exchange resin and production thereof, permselective membrane derived therefrom, and process for producing membrane

Claim 2

A cation exchange resin having a molecular structure comprising a perhalogenated, fluorine-containing hydrocarbon polymeric skeletal substrate which contains no ion exchange group but has attached to it at least one pendant side chain which contains at least one active group, having cation exchange properties, derived from an unsaturated dicarboxylic acid or a derivative thereof and which said side chain also contains at least one vinyl group derived from a vinyl monomer wherein the said side chain is linked to the said substrate by at least one said vinyl group and wherein the molar ratio of said active groups to vinyl groups in the said side chain is in the range of 1:1 to 1:20.

Claim 3

A cation exchange resin according to claim 1 wherein the molar ratio of the active groups to the vinyl groups in the side chain is in the range 1:1 to 1:3.

Claim 4

A cation exchange resin according to either claim 1 or claim 2 wherein the perhalogenated fluorine-containing hydrocarbon polymeric substrate is perfluorinated.

Claim 5

A cation exchange resin according to either claim 1 or claim 2 wherein the perhalogenated fluorine-containing hydrocarbon polymeric substrate also contains chlorine.

Claim 6

A cation exchange resin according to any one of claims 1 to 4 wherein the active group is a dicarboxylic acid, or a derivative thereof, having a general formula represented by wherein X' and X" are independently selected from the group consisting of hydrogen, fluorine, chlorine, an alkyl group and a halogenated alkyl group.

Claim 7

A cation exchange resin according to any one of claims 1 to 4 wherein the active group is

Claim 8

A cation exchange resin according to any one of claims 1 to 6 wherein the vinyl group is derived from a monomer selected from the group of monomers having the general formula of where X is hydrogen or fluorine; and Y is hydrogen, fluorine or chlorine.

Claim 9

A cation exchange resin according to any one of claims 1 to 6 wherein the vinyl group is derived from a monomer selected from the group of monomers having the general formula of where X is hydrogen or fluorine Y is hydrogen or fluorine or chlorine Z is hydrogen, alkyl, alkene, halogenated alkyl or halogenated alkene group.

Claim 10

A process for the preparation of a cation exchange resin comprising a fluorine-containing hydrocarbon polymeric skeletal substrate with at least one active side chain containing at least one ion exchange group derived from a dicarboxylic acid or a derivative thereof in which process a mixture of a vinyl monomeric material and an active monomeric material capable of providing said ion exchange groups is subjected to irradiation . in the presence of a material comprising a fluorine-containing hydrocarbon polymeric skeletal substrate so that part of the said vinyl monomeric material is grafted to the said substrate and so that copolymerisation of the vinyl monomeric material and the active monomeric material takes place to form a product having at least one pendant side chain on the said substrate.

Claim 11

A process for the preparation of a cation exchange resin comprising a fluorine-containing hydrocarbon polymeric skeletal substrate with at least one active side chain containing at least one ion exchange group derived from a dicarboxylic acid or a derivative thereof in which process a mixture of a vinyl monomeric material and an active monomeric material capable of providing said ion exchange groups is subjected to irradiation . in the presence of a material comprising a fluorine-containing hydrocarbon polymeric skeletal substrate so that part of the said vinyl monomeric material is grafted to the said substrate and so that copolymerisation of the vinyl monomeric material and the active monomeric material takes place to form a product having at least one pendant side chain on the said substrate.

Claim 12

A process according to claim 9 wherein the said mixture of monomeric materials consists of vinyl monomeric material and active monomeric material in proportions such that the molecular ratio of vinyl monomer to active monomer is in the range of 20:1 to 1:9.

Claim 13

A process according to either claim 9 or claim 10 wherein the material comprising the said substrate and the said mixture of monomers are subjected together to irradiation by any one form of radiation selected from the group consisting of gamma-rays, X-rays and electron beams.

Claim 14

A process according to any one of claims 9 to 11 wherein the said fluorine-containing hydrocarbon polymeric skeletal substrate is perhalogenated.

Claim 15

A process according to any one of claims 9 to 11 wherein the said substrate is a fluorinated olefin/olefin copolymer.

Claim 16

A process according to any one of claims 9 to 13 wherein the said mixture of monomers is dissolved in a solvent capable of swelling the said material comprising a fluorine-containing hydrocarbon polymeric skeletal substrate.

Claim 17

A perm-selective membrane, suitable for use in electrolysis cells, which comprises a cation exchange resin according to any one of claims 1 to 8.

Claim 18

A process of making a perm-selective membrane according to claim 15, in which process the said cation exchange resin is subjected to compression so as to form it into a thin membrane.

Claim 19

A process of making a perm-selective membrane according to claim 15, in which process a film comprising a perhalogenated fluorine-containing hydrocarbon polymeric substrate is impregnated with a mixture of a vinyl monomeric material and an active monomeric material containing ion exchange groups derived from dicarboxylic acid and said impregnated film is then subjected to irradiation so that the monomers in the said mixture are graft copolymerised to the said substrate to form active side chains on the said substrate.