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. 27, 2001
Filed:
Dec. 14, 1999
Katsushi Sasaki, Yamaguchi, JP;
Wataru Funakoshi, Yamaguchi, JP;
Toru Sawaki, Yamaguchi, JP;
Masumi Hirata, Yamaguchi, JP;
Hiroaki Kaneko, Yamaguchi, JP;
Masanori Abe, Yamaguchi, JP;
Masasi Simonaru, Yamaguchi, JP;
Hidemi Takemoto, Yamaguchi, JP;
Jyuhou Matsuo, Yamaguchi, JP;
Yoshiki Matsuoka, Yamaguchi, JP;
Teijin Limited, Osaka, JP;
Abstract
Aromatic polycarbonate having a reduced discoloration and improved heat stability, hue, etc. is provided by keeping a pressure in a raw material melting vessel and the linear velocity of a gas in a transporting piping in a specific range, keeping the concentration of a nitrogen-containing basic compound in a specific range, recycling a byproduct containing specific amounts of impurities, suppressing the amounts of a nitrogen-containing basic compound, metallic elements and a silicic acid derivative in the carbonic acid diester at specific values or less, prescribing the material quality of the reaction facilities, and/or forming an oxide layer at the inner wall surfaces of the reaction facilities.