04234535 is referenced by 43 patents and cites 4 patents.

A porous polytetrafluoroethylene tubing, useful as artificial internal organs or industrial filtering materials for, for example reverse osmosis, ultrafilteration, etc., having a microporous fibrous structure in which the fibrous structure is composed of fibers and nodes connected with each other and the microporous fibrous structure differs between the outer surface portions of the tubing and the inner surface portions of the tubing, and a process for producing the porous resin tubing comprising heating a tubing made of an unsintered polytetrafluoroethylene under conditions in which the tube is stretched at least in the longitudinal direction of the tubing and such that the outer surface of the tubing is heated above about 327.degree. C. and the inner surface of the tubing is heated to a temperature below the temperature of the outer surface.

Title
Process for producing porous polytetrafluoroethylene tubings
Application Number
751876
Publication Number
4234535
Application Date
June 11, 1979
Publication Date
November 18, 1980
Inventor
Koichi Okita
Osaka
JP
Agent
Sughrue Rothwell Mion Zinn and Macpeak
Assignee
Sumitomo Electric
JP
IPC
B29C 17/07
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