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:
Nov. 07, 1978
Filed:
Jun. 15, 1977
Teijin Limited, Osaka, JP;
Abstract
A process for preparing polyesters having superior thermal stability, transparency and chemical resistance, which comprises (1) a first step of esterifying (A) a difunctional carboxylic acid containing at least 60 mole% of an aromatic dicarboxylic acid, (B) 0 to 80 mole%, based on component (A), of an aliphatic diol and/or a dihydroxybenzene and (C) an aromatic monohydroxy compound in an amount of at least 210 mole% as a total of it and component (B) based on component (A), the esterification being performed until the degree of esterification reaches at least 80%, (2) subsequently, a second step of adding 0 to 80 mole%, based on component (A), of component (B) and a bisphenol (D) in an amount of 100 to 130 mole% as a total of it and component (B) based on component (A) to the reaction product obtained in the first step and reacting the mixture, the total amount of components (B) used in the first and second steps being 0 to 80 mole% based on component (C), and (3) performing at least the first of the above steps in the presence of an aromatic hydrocarbon medium having a boiling point of 105.degree. to 175.degree. C at normal atmospheric pressure and being inert at the reaction temperature.