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:
Oct. 16, 1979
Filed:
Sep. 11, 1978
Stanley D Lazarus, Petersburg, VA (US);
Kalidas Chakravarti, Richmond, VA (US);
Hugh H Rowan, Chester, VA (US);
James G Neal, Raleigh, NC (US);
Allied Chemical Corporation, Morris Township, Morris County, NJ (US);
Abstract
High molecular weight linear condensation polyesters are stabilized against deterioration by heat by reacting the polyester in molten form with certain polycarbonates in the presence of a catalytic amount of a phosphonium compound selected from the group consisting of tetra-n-alkylphosphonium acetates and tetra-n-alkylphosphonium halides. For the purpose of this disclosure, polycarbonates are defined as linear polyesters of carbonic acid in which the carbonate groups recur in the polymer chain. In continuous production of the improved polyesters, it is preferred that the polycarbonate and catalyst be added to the process stream with mixing at a point to give 2 to 15 minutes reaction time under superatmospheric pressure before the polyester enters the last polycondensation reactor.