Toray Industries, Inc.

Tetsuo Watanabe

Masaru Kurihara

Tadahiro Uemura

Yoshio Himeshima

Tetsuo Inoue

Hideaki Tanisugi

Shinichi Yamada

Kuniyasu Shiro

Composite membrane

The present invention relates to a porous membrane which has excellent durability and is useful for ultrafiltration. The porous membrane of the present invention has heterogeneous structure, which consists essentially of a phenylenesulfide-based copolymer of the formula: (Ph--S--Ph--X--).sub.q -- (wherein Ph represents phenylene group, X represents --SO.sub.2 -- or --CO--, and g represents an integer from 80-400 which membrane has a dense layer on one or both surfaces of the membrane, the dense layer controlling the separation performance of the membrane, and a porous layer next to the dense layer, which porous layer has a porosity higher than that of the dense layer.

Porous membrane and production process thereof

A method of producing a semipermeable membrane comprising a polymeric material based upon a trisisocyanurate structure ##STR1## wherein, R.sub.1, R.sub.2 and R.sub.3 are hydrogen or alkyl radicals containing from 2 to 5 carbon atoms, and at least two of R.sub.1, R.sub.2 and R.sub.3 are alkyl radicals having hydroxyl or glycidyl groups. The membrane has high solute rejection, high flux, excellent high pressure resistance, and high temperature resistance and is a highly useful composite membrane for reverse osmosis. In the method, an aqueous solution containing, for example, a reaction product of Formula I is applied to the surface of a porous substrate and is heated at a temperature of about 100.degree. C. to 190.degree. C. to provide a cross-linked structure including a multiplicity of isocyanurate groups on the porous substrate.

Method of making a reverse osmosis semipermeable membrane

A method for the selective separation of at least one water-soluble useful material from an aqueous solution by reverse osmosis is provided. The method comprises contacting the aqueous solution under pressure maintained above the osmotic pressure of the aqueous solution with a semipermeable composite membrane. The semipermeable composite membrane comprises a microporous substrate and a barrier layer having about 0.01 to about 0.1 micron thickness and composed of a cross-linked polymeric material having isocyanurate structures of Formula (I) formed on the microporous substrate: ##STR1## wherein each of R.sub.1, R.sub.2 and R.sub.3 is selected from the group consisting of hydrogen, a glycidyl group, and an alkyl radical containing from 2 to 5 carbon atoms, an alkyl radical carrying a functional hydroxyl group and an alkyl radical carrying a functional glycidyl group, with the proviso that at least two of R.sub.1, R.sub.2 and R.sub.3 are glycidyl groups, alkyl radicals carrying functional hydroxyl groups, alkyl radicals carrying glycidyl groups or a combination thereof. The cross-linked polymeric material has ether linkages, ester linkages or a combination thereof connecting the isocyanurate structures to each other.

Reverse osmosis using a composite isocyanurate membrane

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Otsu, Japan

Tetsuo Watanabe