Nitto-denko Corporation

Takashi Kamada

Shinichi Inoue

Takahisa Konishi

Tomomi Ohara

Hiroki Fujioka

Takuji Shintani

Shinya Nishiyama

Atsuhito Koumoto

Taisuke Yamaguchi

Toshinori Tsuru

Tomohisa Yoshioka

Chunlong Kong

A method for producing a spiral wound separation membrane element includes preparing a composite semipermeable membrane having a skin layer on the surface of a porous support. The method further includes forming on the skin layer a protective layer containing 35 mg/mor more of an anionic polyvinyl alcohol to prepare a protective layer-equipped composite semipermeable membrane, preparing an unwashed spiral wound separation membrane element from the protective layer-equipped composite semipermeable membrane, and passing wash water through the unwashed spiral wound separation membrane element to remove the protective layer on the skin layer.

Method for producing spiral wound separation membrane element

The present invention provides a composite separation membrane with improved separation performance, particularly with an increased permeation flux. The composite separation membrane of the present invention includes a porous support () and a separation functional layer () formed on this support (). The separation functional layer () is a polyamide membrane having a 'double-folded structure' including a first layer portion () with a plurality of projections (, (. . . ) and a second layer portion () that covers at least one or some (and) of these projections. Some projections (and) of the first layer portion () extend upward and branch to form the second layer portion (). There is a vacant space () between the first layer portion () and the second layer portion ().

Composite separation membrane and separation membrane element using the same

The present invention aims at providing a process for producing a dried composite semipermeable membrane having extremely small content of unreacted components, outstanding water permeability and salt-blocking rate even after drying treatment, and outstanding contamination resistance and durability. The present invention relates to a process for producing a dried composite semipermeable membrane comprising the steps of: preparing a composite semipermeable membrane having a skin layer including a polyamide resin obtained by reaction between a polyfunctional amine component and a polyfunctional acid halide component formed on the surface of a porous support; washing the composite semipermeable membrane; contacting a moisturing solution including a moisturizer and a hydrophilization agent only to the surface of the porous support of the washed composite semipermeable membrane and contacting a protecting solution only to the surface of the skin layer of the washed composite semipermeable membrane; and drying the treated composite semipermeable membrane.

Process for producing a dried composite semipermeable membrane

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Osaka, Japan

Takashi Kamada