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:
Aug. 02, 1977
Filed:
Oct. 06, 1975
Joerg Rebhan, Ludwigshafen, DT;
Hans Georg Matthies, Ludwigshafen, DT;
BASF Aktiengesellschaft, Ludwigshafen, DT;
Abstract
An improved process for the continuous manufacture of linear high molecular weight polyesters by direct esterification of terephthalic acid with excess glycols in a medium comprising terephthalic acid glycol esters or their oligomers, under superatmospheric pressure at temperatures above 200.degree. C, followed by polycondensation in the presence of catalysts at from 260.degree. to 290.degree. C. The improvement is that the mixture fed to the esterification contains terephthalic acid and glycols in the molar ratio of 1:1.15 to 1:1.5 and that during the esterification from 20 to 30% by weight of the excess of glycols over the molar ratio terephthalic acid: glycols = 1:1 are continuously distilled from the reaction mixture.