Mitsubishi Rayon Company, Limited

Mitsubishi Chemical Corporation

Masakazu Minagawa

Masashi Teramachi

Toshinori Sumi

Yoshie Tanizaki

Kei Murase

Hiroyuki Fujiki

Yasuo Hiromoto

Masaki Kurashina

Ayumi Tanaka

Kana Inoue

A potting material for membrane modules which is formed of an epoxy resin composition, in which the mass change ratio of a cured product of the epoxy resin composition after being immersed in diethylene glycol methyl ethyl ether at 40&#xb0; C. for one week is &#xb1;10% or less, and the mass change ratio thereof after being immersed in tetrahydrofurfuryl acrylate at 40&#xb0; C. for one week is &#xb1;5% or less, and a hollow fiber membrane module which uses the potting material for membrane modules.

Potting material for membrane modules and hollow fiber membrane module using same

Disclosed is a process for production of a porous membrane that includes the steps of layering a film-forming dope that contains a polymer (A) that forms a membrane base, a polyvinylpyrrolidone (B) and a solvent (C) into a single layer or two or more layers; immersing the film-forming dope in a solidifying fluid that is a non-solvent with respect to the polymer (A) and is a good solvent with respect to the polyvinylpyrrolidone (B); and removing the polyvinylpyrrolidone (B), wherein the polyvinylpyrrolidone (B) has a K value of 50 to 80, a mass ratio r of the polyvinylpyrrolidone (B) to the polymer (A) is 0.5 or more and less than 1, and the viscosity of the film-forming dope at a membrane production temperature is 100 to 500 Pa&#xb7;s. Accordingly, by using an appropriate amount of a low-molecular-weight hydrophilic polymer capable of being easily removed, it is possible to produce a porous membrane of a three-dimensional network structure in which macrovoids are suppressed, having high water permeability and superior filtration performance.

Process for production of porous membrane

A hollow porous membrane with a reduced cost and excellent separation characteristic, water permeability, and mechanical strength and a process of producing the hollow porous membrane with an excellent adhesive property between a support and a porous membrane layer at a low cost are provided. The hollow porous membrane includes a porous membrane layer in which dense layers are disposed in the vicinities of an outer surface and an inner surface. In the process of producing the hollow porous membrane, membrane-forming dopes of a first membrane-forming dope and a second membrane-forming dope, which contain the material of the porous membrane layer and a solvent, are successively applied and stacked onto the outer circumferential surface of a hollow support and the applied membrane-forming dopes are simultaneously coagulated. In the process of producing the hollow porous membrane, a porous membrane layer is formed by applying a membrane-forming dope containing a material of the porous membrane layer and a solvent to the outer circumferential surface of the hollow support and coagulating the applied dope, and a hollow braid obtained by circularly knitting a yarn formed of multi-filaments is used as the support.

Hollow porous membrane and process for producing the same

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Toyohashi, Japan

Masakazu Minagawa