The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 1995
Filed:
Aug. 01, 1991
Tai-Shung Chung, Randolph, NJ (US);
Edward R Kafchinski, Winfield, NJ (US);
Rohitkumar H Vora, Westfield, NJ (US);
Hoechst Celanese Corp., Somerville, NJ (US);
Abstract
Asymmetric hollow fibers of SIXEF.TM.-Durene, a polyimide made from 2,2-bis[3,4-dicarboxyphenyl] hexafluoropropane dianhydride and 2,3,5,6-tetramethylphenylene diamine monomers, and a process for making such fibers. These uncoated fibers have a separation factor that exceeds 4 for oxygen and nitrogen and a permeance of at least about 50 ppm cc(STP)/(sec cm.sup.2 cm-Hg). A polymer dope comprising SIXEF.TM.-Durene in a solvent system containing N-methyl-2-pyrrolidone ('NMP') and an organic acid such as propionic acid ('PA') is prepared by polymerizing the polyimide monomers in NMP to form a polyamic acid polymer and imidizing this polymer using the acid anhydride. Water released from the polymer in the imidization reaction converts the anhydride to the organic acid. The dope is wet-spun into hollow fibers using a core solvent such as PA or glycerine; the fibers are coagulated in water.