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:
May. 23, 1995
Filed:
Mar. 14, 1994
Takeshi Sakashita, Iwakuni, JP;
Tomoaki Shimoda, Iwakuni, JP;
Kotaro Kishimura, Iwakuni, JP;
Shuichi Uchimura, Otake, JP;
GE Plastics Japan, Tokyo, JP;
Abstract
The method of this invention prepares copolymeric polycarbonates which have excellent mechanical properties, heat resistance and transparency, and which also have improved chemical resistance, hue, and residence stability by inducing the melt polycondensation of an aromatic dihydroxy compound containing an amount of 2-90 mol % of hydroquinone and/or substituted hydroquinones with a diester carbonate in the presence of a catalyst containing alkali metal compounds and/or alkaline earth metal compounds in an amount of 1.times.10.sup.-8 to 5.times.10.sup.-6 mole per mole of the total amount of the aromatic dihydroxy compound.