Nippon Steel Chemical Co., Ltd.

Nippon Steel Corporation

Masaya Furukawa

Kazuhiro Watanabe

Takero Teramoto

Yasuharu Yamada

Nobuyuki Furukawa

Kazuhiro Sugiyama

Masao Sakashita

Koichi Fujishiro

Hironobu Kawasato

Shingo Kazama

Tsutomu Kaneta

Kazuto Shiraishi

Takerou Teramoto

Tutomu Kaneta

Ortho spiroesters and curable and cured resin compositions of same

This invention relates to separation membranes composed of a mixture of two kinds or more of polymers containing at least one kind of polymer selected from polyesters, polyethers, polycarbonates, polyamides, and polyimides with a fluorene skeleton and possessing a spongy structure throughout and the membranes can be made by a known simple process, have not only excellent separatory ability but also good mechanical properties, and are particularly useful for ultrafiltration membranes and gas separation membranes.

Separation membranes

Polyimide copolymers of this invention have a repeating unit of the general formula (1) ##STR1## wherein Ar.sub.1 is a tetravalent organic radical containing at least one aromatic ring, R.sub.1 is a divalent organic radical, R.sub.2 and R.sub.3 are monovalent hydrocarbon radicals, and n is an integer from 0 to 4 and a repeating unit of the general formula (2) ##STR2## wherein Ar.sub.2 is a tetravalent organic radical containing at least one aromatic ring, R.sub.6 is a divalent organic radical, R.sub.7 is a monovalent hydrocarbon radical with 1 to 6 carbon atoms, and l is an integer from 5 to 50 and are capable of forming films of a microdomain structure useful for such applications as protective films on semiconductors, coatings adhesives, moldings, films, and separation membranes.

Polyimide copolymers and process for preparing the same

A separation membrane comprising a soluble aromatic polysulfone having the formula --(X--Y)--, wherein X and Y comprise the constituent unit shown below, and the inherent viscosity (.eta..sub.inh) based on the value of a solution of 0.5 g of the polysulfone dissolved in 100 ml of N-methyl-2-pyrrolidone measured at 30.degree. C. is 0.4 or more: ##STR1## wherein R.sub.1 -R.sub.4 are each either H, CH.sub.3 or C.sub.2 H.sub.5, and R.sub.5 -R.sub.6 are each either H, Cl, or NO.sub.2.

Polysulfone separation membrane

Polyimide-based separation membranes of this invention are made from polyimides having repeating units of the general formulas (A) and (B) ##STR1## wherein Ar.sub.1 and Ar.sub.3 are tetravalent aromatic radicals containing at least one aromatic ring, Ar.sub.2 is a divalent aromatic radical containing at least one aromatic ring, R.sub.1 and R.sub.2 are organic radicals, R.sub.3 to R.sub.6 are monovalent hydrocarbon radicals, and n is an integer from 1 to 50 at a mole ratio (A)/(B) of 5/95 to 95/5, have high gas permeation coefficients, high mechanical strength, and excellent heat resistance, and are useful for separation and concentration of mixed gases.

Separation membranes and process for preparing the same

Growing community of inventors

Kawasaki, Japan

Masaya Furukawa