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:
Jun. 25, 2002
Filed:
Aug. 01, 2001
Makoto Ishida, Tokyo, JP;
Koji Ishihata, Tokyo, JP;
Koji Maeda, Tokyo, JP;
Wataru Funakoshi, Iwakuni, JP;
Hiroaki Kaneko, Iwakuni, JP;
Yuichi Kageyama, Iwakuni, JP;
Katsushi Sasaki, Iwakuni, JP;
Teijin Limited, Osaka, JP;
Abstract
An aromatic polycarbonate which has high durability and is excellent in color tone, transparency and mechanical strength, especially an aromatic polycarbonate which has high durability and stability when it is used under high temperature and high humidity conditions for a long time, and production method and use thereof. In the aromatic polycarbonate which has a sodium element content of 100 ppb or less and a content of each of Ni, Pb, Cr, Mn and Fe of 70 ppb or less and the method of producing a polycarbonate by polycondensing an aromatic dihydroxy compound and a carbonic acid diester, the above aromatic polycarbonate is produced by controlling 1) the content of sodium element contained in each of the above raw materials to 52 ppb or less, 2) the content of each of Fe, Cr, Mn, Ni and Pb to 40 ppb or less and 3) the amount of a specific catalyst to a specific value based on the content of Fe contained in the raw materials.