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:
May. 23, 1995
Filed:
Dec. 15, 1993
Rhone-Poulenc Viscosuisse SA, Emmenbrucke, CH;
Abstract
Process for making a polyester having polyethylene terephthalate units including transesterifying a terephthalic acid ester with a glycol using a manganese salt as catalyst and then subjecting the product to a polycondensation reaction using a germanium-containing catalyst to form a polyester; adding phosphorous compounds to block 80 to 99% by weight of the active manganese salt thus leaving an unblocked portion of the manganese salt prior to the polycondensation; and adding 10 to 100 ppm of Ge at the end of a ethylene glycol stage of the polymerization so that the Ge and the unblocked portion of the manganese salts provide the germanium-containing catalyst for the polycondensation reaction. The P/Mn molar ratio being less than 1. The reaction mixture contains 10 to 100 ppm of manganese during the reaction.