Teijin Limited

Yuzuru Hayashi

Takeyuki Kawaguchi

Yutaka Taketani

Shigeyoshi Hara

Hiroyoshi Minematsu

Noriaki Sasaki

Tomoyoshi Ono

Koh Mori

Fumio Ueda

Ko Mori

An amphoteric ion-permeable composite membrane composed of a microporous substrate, and supported on the substrate, a thin amphoteric ion-exchange film formed of an active amino group-containing polymer which has been interfacially crosslinked at least at the surface portion of the thin film, said membrane being produced by forming a thin layer comprising an active amino group-containing polymer containing 1.0 to 23 milliequivalents/g, as amino equivalent, of an active amino group selected from primary and secondary amino groups and 0 to 18 milliequivalents/g, as amino equivalent, of a tertiary amino group and/or an ammonium salt group per molecule with the total amino content thereof being in the range of 2.0 to 23 milliequivalents/g on the microporous substrate and then contacting the thin layer on the substrate interfacially with a polyfunctional aromatic compound containing at least two functional groups selected from carbonyl halide groups, sulfonyl halide groups, carboxylic acid anhydride groups, sulfonic acid anhydride groups and derivative groups of carboxylic acids and sulfonic acids having equivalent reactivity to the aforesaid halide and anhydride groups.

Amphoteric ion-permeable composite membrane

A semipermeable composite membrane comprising a thin semipermeable film of a polymeric material deposited on one side of a microporous substrate, the polymeric material being prepared by crosslinking a soluble polymer containing at least 30 mole % of a recurring unit of the formula ##STR1## wherein all symbols are as defined herein, and having at least 0.5 milliequivalent, per gram of said polymer, of an amino group containing 1 or 2 active hydrogen atoms, with a polyfunctional compound containing at least two functional groups capable of reacting with the amino group having 1 or 2 active hydrogen atoms; and a process for preparing the same. The semipermeable composite membrane of this invention is especially useful for desalination of saline or brackish water by reverse osmosis.

Semipermeable composite membrane

A semipermeable composite membrane comprising a thin semipermeable film of a polymeric material deposited on one side of a microporous substrate, said polymeric material being prepared by crosslinking a soluble polymer containing at least 30 mole % of a recurring unit of the formula ##STR1## wherein all symbols are as defined in claim 1, and having at least 0.2 milliequivalent, per gram of said polymer, of an amino group containing 1 or 2 active hydrogen atoms, with a polyfunctional compound containing at least two functional groups capable of reacting with the amino group having 1 or 2 active hydrogen atoms; and a process for preparing the same. The semipermeable composite membrane of this invention is especially useful for desalination of saline or brackish water by reverse osmosis.

A permselective membrane comprising a thin permselective film of a polymeric material, said polymeric material being prepared by cross-linking a polyaddition product between a polyepoxy compound and a polyamino compound having at least two amino groups capable of reacting with epoxy groups with a polyfunctional compound selected from the group consisting of aromatic, heterocyclic and alicyclic compounds containing at least two functional groups selected from acid halide, sulfonyl halide, isocyanate and acid anhydride groups; and a process for producing the same. The permselective membrane of this invention is especially useful for desalination of saline or brackish water by reverse osmosis.

Permselective membrane

A process and composition for producing a permselective composite membrane. The process comprises dissolving a specified imidazolone ring-containing aromatic polymer in an aqueous liquid medium containing a water-miscible amine having a pKa of more than 5.0 in a concentration of at least 5% by weight, coating the polymer solution on a microporous substrate, and drying the coating to form an ultrathin film on the substrate. The permselective composite membrane obtained is especially useful as a reverse osomsis membrane.

Preparation of permselective composite membrane

A semipermeable composite membrane comprising a thin semipermeable film of a polymeric material deposited on one side of the microporous substrate, said polymeric material being prepared by interfacial crosslinking of a polymer containing a recurring unit of the formula ##STR1## wherein each of R.sub.1 and R.sub.2 represents a hydrogen atom or a methyl group, and W.sub.1 represents a direct bonding or a sulfonyl group (--SO.sub.2 --), with a polyfunctional compound containing at least two functional groups selected from acid halide, sulfonyl halide, isocyanate, N-haloformyl, haloformate and acid anhydride groups; and a process for producing the same. The semipermeable composite membrane of this invention is especially useful for desalination of saline or brackish water by reverse osmosis.

Growing community of inventors

Iwakuni, Japan

Yuzuru Hayashi