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. 09, 1993
Filed:
Feb. 20, 1992
Johannes M Verheijen, Ranst, BE;
August M Marien, Westerlo, BE;
Agfa-Gevaert, N.V., Mortsel, BE;
Abstract
A continuous direct esterification and polycondensation process is disclosed for the production of polyester comprising units of ethylene terephthalate as the major repeating units by supplying a slurry of mainly terephthalic acid and ethylene glycol to bis(betahydroxyethyl) terephthalate or its oligomer so as to carry out esterification, followed by polycondensation whereby the resulting oligomer is kept under increasingly reduced pressure, characterized in that a stabilizing solution of an aliphatic diol containing a diethyl or tributhyl phosphite and a hindered phenolic phosphonate is added to the reaction mixture before the start of the polycondensation.