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. 07, 1983
Filed:
Dec. 22, 1980
Gernot Horlbeck, Haltern, DE;
Horst Heuer, Haltern, DE;
Hanns-Jorg Bax, Marl, DE;
Hans Jadamus, Marl, DE;
Chemische Werke Huels AG, Marl, DE;
Abstract
A process for condensing a linear polyalkylene terephthalate having a viscosity number of at least 60 cc/g in two stages, at an elevated temperature, in the solid phase, and in the presence of an alkanediol, comprises, in a first stage, treating the polyalkylene terephthalate in an inert gas stream at a reaction temperature 30.degree.-80.degree. C. below its melting point, with 0.2-3.5% by weight, based on the weight of the polyalkylene terephthalate, of an alkanediol whose boiling point under normal pressure is 20.degree.-70.degree. C. above the reaction temperature, wherein the amount of inert gas passed through per hour, measured under standard conditions, corresponds to 0.3 to 2 times the gross reactor volume; and, in a second stage, condensing the polyalkylene terephthalate in an inert gas stream at a temperature 5.degree.-25.degree. C. below its melting point, wherein the amount of inert gas passed through per hour, measured under standard conditions, corresponds to 2.5 to 10 times the gross reactor volume.