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:
Mar. 27, 1979
Filed:
Apr. 07, 1977
George R Goodley, Kinston, NC (US);
Donald A Shiffler, Kinston, NC (US);
E. I. Du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
A continuous process is disclosed for direct esterification of terephthalic acid with ethylene glycol to form low molecular weight polyester with recovery of excess glycol from reaction off-gases. The terephthalic acid is mixed with an excess of glycol, the mixture is reacted at 280.degree.-315.degree. C. in reaction product circulated from a reactor through an external heater and back to the reactor, and reaction product is withdrawn from the reactor for polymerization to high molecular weight polyester. Vapors formed in the reactor are fed into the bottom of a rectification column where the excess glycol is recovered for direct reuse. The vapor feed is sprayed with condensate at 140.degree.-195.degree. C. in the bottom of the column to remove solids and maintain conditions suitable for obtaining less than 0.05 percent glycol in overhead distillate and 0.3 to 10 percent water in glycol condensate.