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:
Jun. 17, 1980
Filed:
Mar. 12, 1979
Chemische Werke Huls, Aktiengesellschaft, Marl, DE;
Abstract
In a process for preparing high molecular weight poly-(ethylene terephthalate) in two stages, comprising, in the first stage, reacting a dialkyl ester of terephthalic acid with ethylene glycol in the presence of 35 to 290 ppm of manganese, in the form of a manganese-II salt effective as a catalyst, together with 6 to 95 ppm of cobalt, in the form of a cobalt-II salt effective as a catalyst, at a temperature of 170.degree. to 220.degree. C. to give a low molecular weight precondensate; then adding 45 to 140 ppm of phosphorus in the form of a phosphorus compound effective to minimize discoloration of the product poly-(ethylene terephthalate) due to said transesterification catalysts; and, in the second stage, effecting complete condensation of the precondensate thus obtained, in the presence of catalysts at a temperature of 270.degree.-290.degree. C. and under low pressure, to give high molecular weight poly-(ethylene terephthalate),