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:
Oct. 16, 2001
Filed:
Nov. 19, 1999
Teijin Limited, Osaka, JP;
Abstract
The relative intensity of fluorescent light of a melt-polycondensed aromatic polycarbonate produced by the transesterification process (melt polymerization process) of an aromatic dihydroxy compound and a carbonic acid diester in the presence of a catalyst comprising a basic nitrogen compound and/or a basic phosphorus compound in combination with an alkali metal compound is suppressed to 4.0×10,or below at a wavelength of 465 nm based on a standard substance in a fluorescent light spectrum obtained by the excitation wavelength of 320 nm. An aromatic polycarbonate having good color stability, especially good stability to the deterioration of the chip color during storage of the chip in air at room temperature can be produced by the present invention.