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:
Apr. 01, 1980
Filed:
Jul. 11, 1978
Teijin Limited, Osaka, JP;
Abstract
An improved process for producing a linear polyester having a high degree of polymerization which comprises first preparing a prepolymer of polyester and then polycondensing the prepolymer. In the first step, a prepolymer having an intrinsic viscosity of at least 0.2 is prepared, and the subsequent polycondensation is carried out in the presence of an organic boron compound of the formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represent an alkyl, aralkyl or aryl group having 6 to 20 carbon atoms, and M represents a monovalent metal. According to this method, the polycondensation can be performed at atmospheric pressure, and a substantially linear polyester having an intrinsic viscosity of at least 0.5 and superior thermal stability can be obtained rapidly.