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:
Feb. 24, 1998
Filed:
Oct. 07, 1996
Applicant:
Inventors:
Joseph Richard Wetzel, Watervliet, NY (US);
Andrew James Caruso, Schenectady, NY (US);
Assignee:
General Electric Company, Schenectady, NY (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C08J / ;
U.S. Cl.
CPC ...
521 49 ; 521 495 ; 526262 ; 528488 ; 528492 ; 528503 ;
Abstract
Polyimides, especially thermoset polyimides such as those prepared by the reaction of p-phenylenediamine with 4,4'-hexafluoroisopropylidenebis(phthalic anhydride) and nadic ester, are converted to monomers which may be recycled for polyimide synthesis by heating with a solution of an alkali metal hydroxide, such as lithium hydroxide or sodium hydroxide, in a dipolar aprotic solvent such as N-methylpyrrolidone. The products are the diamine and the tetracarboxylic acid alkali metal salt corresponding to the dianhydride.