Nitto-denko Corporation

Taisuke Yamaguchi

Masashi Echizen

Kazusa Matsui

Shinichi Inoue

Takahisa Konishi

Hiroki Fujioka

Shinya Nishiyama

Atsuhito Komoto

Atsuko Mizuike

Takashi Kamada

Yasuyuki Sakakibara

The present invention provides a spiral membrane element in which the effective membrane area of a composite semi-permeable membrane can be increased and any decrease in rejection rate is less likely to occur. The spiral membrane element includes: a laminate including a permeation-side flow path material, a supply-side flow path material, and a composite semi-permeable membrane having a separation function layer on a surface of a porous support; a perforated central tube around which the laminate is wound; and a sealing member for preventing mixing between the supply-side flow path and a permeation-side flow path, the spiral membrane element being characterized in that the thickness of the porous support of the composite semi-permeable membrane is 80 &#x3bc;m to 100 &#x3bc;m, the permeation-side flow path material is formed from a tricot knit fabric, and the width of a groove that continues in a straight line is 0.05 mm to 0.40 mm.

Spiral membrane element

The objective of the present invention is to provide a composite semi-permeable membrane having high processing efficiency even when processing of wastewater having a suspended matter content high enough to tend to result in clogging, said processing efficiency being unlikely to decline even under elevated-pressure operation accompanying continuous use at high pressure. The present invention pertains to a composite semi-permeable membrane having a polymer porous layer on one surface of a nonwoven cloth layer, and a polyamide separation function layer on the polymer porous layer, wherein the ratio of the thickness of the polymer porous layer to the thickness of the nonwoven cloth layer is 0.22 to 0.45.

Composite semi-permeable membrane

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

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Osaka, Japan

Taisuke Yamaguchi