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. 20, 1980
Filed:
Aug. 17, 1978
Marvin Z Woskow, Houston, TX (US);
Denka Chemical Corporation, Houston, TX (US);
Abstract
Tetrahydrophthalic anhydride for the preparation of polyesters is conveniently prepared in a stable, liquid form for transportation and storage by adding molten anhydride to a 100.degree. to 120.degree. C., C.sub.2 to C.sub.9 glycol at rate to maintain this temperature range without raising the temperature of the mixture in increments of more than 5.degree. F., reacting the mixture for a sufficient time to reduce the acid number of the mixture to a number in the range below the theoretical acid number for the half ester of the glycol and anhydride and 165; thereafter cooling the mixture to 155.degree. C., adding glycol as necessary to provide a mole ratio of glycol to anhydride in the range of 1.2 to 2:1 and cooling the mixture to a temperature in the range of 40.degree. to 70.degree. C.