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:
Apr. 03, 1990
Filed:
May. 23, 1988
William E Wright, Baton Rouge, LA (US);
Ethyl Corporation, Richmond, VA (US);
Abstract
A polyimide precursor suitable for use in the pseudo hot-melt prepregging process is described. It consists essentially of a mixture of (a) about 40 to about 70 percent by weight of a substantially equimolar mixture of (i) 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane or 2,2-bis[4-(3-aminophenoxy)phenyl]hexafluoropropane, or both, and (ii) lower alkyl diester of aromatic tetracarboxylic acid; (b) about 2 to about 50 percent by weight of polyamide (polyamic acid or ester) producible from components (i) and (ii); and (c) about 10 to about 50 percent by weight of solvent with the proviso that the mixture is a clear resinous solid at 25.degree. C. and is a viscous, tacky, varnish-like liquid at a temperature falling in the range of 40.degree. C. to 100.degree. C. Also described are use of the polyimide precursors in preparing coated paper webs useful in preparing paper-backed prepregging tape, and use of the coated paper webs in preparing the paper-backed prepregging tapes.