Kurashiki Boseki Kabushiki Kaisha

Dupont Mitsui Fluorochemicals

Yoshihiro Hori

Akihisa Inoue

Tokuya Miyagi

Shoichi Fujimori

Katushi Hamada

A method for the granulation of polytetrafluoroethylene powder comprises spraying a binder solution on the powder while the powder is stirred and ground. The binder solution is an aqueous surfactant solution having a surface tension of 25 dyne/cm or lower at 20.degree. C. and contains polytetrafluoroethylene colloidal particles.

Method for the granulation of polytetrafluoroethylene powder

The present invention provides a filter element made wholly of fluorocarbon resin, including as essential elements a filter material produced by folding a sandwich-form sheet comprising a filter membrane made of a fluorocarbon resin and net supporters made of a thermoplastic fluorocarbon resin superimposed on the both surfaces thereof into a pleat form and liquid-tightly welding the edge parts of the both sides of the pleated sheet, sealed end parts produced by embedding the both end parts of said filter material except the central openings into a thermoplastic fluorocarbon resin to force the resin into the pleats, whereby the both end parts are each integrally and tightly welded, and fluorocarbon resin caps welded liquid-tightly with said sealed end parts, and production thereof. The filter element of the present invention is characterized in that materials for the element are wholly a fluorocarbon resin, so that problems of chemicals resistance, temperature resistance and metal leaching are not caused, and besides that fluorocarbon resins which have so far been regarded as difficult to weld together, are in a liquid-tightly welded state by the special constitution.

Fluorocarbon filter element

The present invention provides a filter element made wholly of fluorocarbons resin, comprising as essential elements a filter material produced by folding a sandwich-form sheet comprising a filter membrane made of a fluorocarbon resin and net supporters made of a thermoplastic fluorocarbon resin superimposed on the both surfaces thereof into a pleat form and liquid-tightly welding the edge parts of the both sides of the pleated sheet, sealed end parts produced by embedding the both end parts of said filter material except the central openings into a thermoplastic fluorocarbon resin to force the resin into the pleats, whereby the both end parts are each integrally and tightly welded, and fluorocarbon resin caps welded liquid-tightly with said sealed end parts, and production thereof.

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Shimizu, Japan

Yoshihiro Hori