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:
Jan. 11, 1994
Filed:
May. 28, 1992
M Ishaq Haider, Bernardsville, NJ (US);
Edward C Chenevey, North Plainfield, NJ (US);
Hoechst Celanese Corp., Somerville, NJ (US);
Abstract
A process for enhancing the thermo-oxidation stability of a polybenzimidazole-containing article wherein the article contains from about 5 to about 100 weight percent of polybenzimidazole and from about 0 to about 95 weight percent of a thermoplastic polymer, by the steps of providing a phosphoric acid solution of about 2.0 to about 10.0 weight percent of acid; contacting the polybenzimidazole-containing article with the acid solution for sufficient time to produce an acid-treated article; drying the acid-treated article at a low temperature to remove excess acid; and heat treating the dried article at a temperature ranging from about 400.degree. to about 500.degree. C. in an inert atmosphere to form a phosphate barrier layer on the surface of the article, wherein the article retains at least about 50 percent of its weight after isothermal aging at about 600.degree. F. for a period of at least about 300 hours.