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. 09, 1990
Filed:
Apr. 04, 1988
William E Wright, Baton Rouge, LA (US);
Ethyl Corporation, Richmond, VA (US);
Abstract
Prepreg precursors and other normally non-flowable resinous semi-solid or viscous liquid polyimide precursor compositions often need to be transformed into free-flowable liquids without dilution and without causing changes in their chemical composition. Such compositions are composed of (a) a diester of an aromatic tetracarboxylic acid, (b) an aromatic diamine, (c) a polyamic acid producible from (i) an aromatic diamine and (ii) a dianhydride of an aromatic tetracarboxylic acid, and (d) an inert solvent in an amount insufficient to provide a flowable liquid at room temperature. Such compositions readily undergo chemical change (amidization and imidization) when subjected to heating in a conventional oven because of local overheating, and poor heat transfer within the body of the composition. These problems are overcome by subjecting the composition to microwave radiation of intensity sufficient to convert at least a portion of the composition into a flowable liquid without causing a significant change in its chemical composition.