Daicel Corporation

Daicel Chemical Industries, Ltd.

Tanabe Seiyaku Company, Limited

Zenjiro Honda

Kiyoshi Ishii

Hitoshi Tsugaya

Ryoshu Suzuki

Masahiro Kagotani

Tadashi Sato

Taizo Watanabe

Shinji Nagamatsu

Satoshi Minobe

Takashi Nishimura

Tomonobu Ase

Pyrogens are removed out of a solution thereof by (1) treating the solution with a membrane and then (2) treating the resulting solution with a pyrogen adsorbent. The obtained solution is useful in pharmaceutical fields.

Process for removing pyrogens

A semipermeable membrane composed of a water-insoluble, cross-linked, membrane-forming polymer (hereinafter referred to as 'polymer (II)') which is obtained by partially converting the hydroxyl groups of a polymer represented by the following formula (hereinafter referred to as 'polymer (I)'): ##STR1## wherein R and R' are halogen, nitro, methyl or ethyl,

Semipermeable membrane

A semipermeable membrane suitable for the use in an artificial kidney of the filtration type is produced by preparing a solution of cellulose acetate in a solvent mixture consisting essentially of a solvent for cellulose acetate and a swelling agent and spreading said solvent on a substrate, the solvent being a mixture of dimethylformamide and acetone, the swelling agent being a mixture of cyclohexanone and water, the ratio by weight of the amount of dimethylformamide and that of acetone to that of the swelling agent being within the area defined by four points consisting of A (60, 20, 20), B (35, 45, 20), C (25, 35, 40) and D (50, 10, 40) in the triangular coordinates represented by FIG. 1; the ratio of cyclohexanone to water being in a range of from 0.8 to 1.3.

Process for preparing semipermeable membrane having selective

A semipermeable membrane composed of a water-insoluble, membrane-forming polymer (hereinafter referred to as 'polymer (II)') which is obtained by partially converting the hydroxyl groups of a polymer represented by the following formula (hereinafter referred to as 'polymer (I)'): ##STR1## wherein R and R' are halogen, nitro, methyl or ethyl, X stands for a divalent group selected from methylene, ethylene, isopropylidene, ether (--O--), carbonyl (--CO--), sulfide (--S--), sulfoxide (--SO--) and sulfone (--SO.sub.2 --), l and m are integers of from 0 to 4, p is 0 or 1, and n is an integer of from 100 to 1000, to sulfuric acid groups or alkali metal, ammonium or nitrogen-containing basic organic compound salts thereof.

Semipermeable membrane of phenoxy resin containing sulfuric acid groups

A semipermeable membrane for ultrafiltration is prepared by Dissolving a copolymer of acrylonitrile (90 to 60 molar percent based on total monomers) and a non-electrolytic water-soluble vinyl monomer (40 to 10 molar percent based on total monomers) in a solvent selected from

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Toyonaka, Japan

Zenjiro Honda