Asahi Kasei Kogyo Kabushiki Kaisha

Takashi Nohmi

Takao Yamada

Yasuo Hashino

Yoshinao Doi

Toshibumi Fukai

Aromatic polysulfone type resin hollow fiber membrane and a process for

There is disclosed a composite membrane comprising [A] a polysulfone type porous membrane capable of rejecting 90% or more of dextran molecules having a weight average molecular weight of 70,000 and [B] a specific styrene type resin coated on at least one side of the polysulfone type porous membrane in a thickness of 5 .mu.m or less and in an amount of 1.times.10.sup.-7 g/cm.sup.2 of the polysulfone type porous membrane, the styrene type resin being selected from the group consisting of (I) a specific styrene type linear polymer having a weight average molecular weight of 1.times.10.sup.-5 or more, (II) a specific blend polymer prepared by blending at least two different styrene type linear polymers each as defined above and (III) a specific crosslinked polymer selected from the group consisting of (i) a crosslinked polymer prepared by crosslinking a styrene type linear polymer having a weight average molecular weight of 1.times.10.sup.-3 or more and (ii) a crosslinked polymer prepared by blending at least two different styrene type linear polymers each having a weight average molecular weight of 1.times.10.sup.3. Such a composite membrane has been found to be advantageously employed for gas separation because of its high gas permeability and high selective gas permeability.

Composite membrane for use in gas separation

An aromatic polysulfone type resin hollow fiber membrane having a thickness of less than 100 .mu.m and a three-layer structure of inner and outer surface skin layers and a void layer disposed therebetween and connected thereto. The hollow fiber membrane of the kind has an improved burst strength, while exhibiting an extremely excellent water permeability. Such a hollow fiber membrane can be produced by a process which comprises extruding a spinning solution of an aromatic polysulfone type resin in an organic polar solvent for said resin, said solution containing a glycol and having a resin concentration of from 10 to 35% by weight, from an annular spinning nozzle of which the orifice width is 10 to 110 .mu.m while simultaneously injecting an internal coagulating liquid into the annular spinning nozzle at an inside bore thereof, thereby to obtain an extrudate in the form of a hollow fiber, and introducing said extrudate into an external coagulating liquid.

Aromatic polysulfone type resin hollow fiber membrane and process for

Polyvinylidene fluoride type resin hollow filament microfilter and

A specific porous membrane is found to be extremely useful for permeation-separation of an oil from an oil-containing emulsion. By contacting a stable oil-containing emulsion of either water-in-oil type or oil-in-water type with the surface of a specific porous membrane having at its surface a critical surface tension of less than 35 dynes/cm to not less than 20 dynes/cm and having an average pore diameter of 0.03 .mu.m to 5 .mu.m, a pore radius distribution of not more than 1.5 and a porosity of 1 to 85%, only the oil can be permeation-separated, without permeation of the liquid immiscible with the oil, with high selectivity and high oil permeation.

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Fuji, Japan

Takashi Nohmi