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:
Jan. 03, 1978
Filed:
Jan. 21, 1975
Shoji Kawase, Iwakuni, JA;
Takatoshi Kuratsuji, Iwakuni, JA;
Hiroo Inata, Iwakuni, JA;
Kazuyoshi Suzuki, Iwakuni, JA;
Takeo Shima, Iwakuni, JA;
Teijin Limited, Osaka, JA;
Abstract
A process for preparing polyesters, which comprises reacting (A) a difunctional carboxylic acid component containing at least 50 mol% of a naphthalene dicarboxylic acid and/or its ester-forming derivative, (B) a diol component containing an aromatic group and at least 50 mol% of a 4,4'-bis-(.omega.-hydroxyalkoxy)diphenylsulfone and (C) an aliphatic or alicyclic diol component, the molar ratio of component (B) to component (A) being 0.05-1, and the molar ratio of the sum of components (B) and (C) to component (A) being 1.1-3.0; and then polymerizing the resulting reaction product in the presence of a catalyst while distilling off the excess of the component (C) out of the reaction system, thereby to form a polymer having a reduced viscosity of at least 0.5.