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:
Jul. 23, 2002
Filed:
Jul. 11, 2001
Young Chan Ko, Seoul, KR;
Il Seok Choi, Kyunggi-do, KR;
Cheol-Hyun Kim, Ulsan, KR;
Kwang Soo Yoon, Kyungsangnam-do, KR;
Seung-Joo Kim, Ulsan, KR;
Kil-Yeong Choi, Daejeon, KR;
Jae Heung Lee, Daejeon, KR;
Kyong Soon Lee, Seoul, KR;
Other;
Abstract
The present invention relates to a process of preparing polycarbonates and more particularly, to the process of preparing polycarbonates through a melt polymerization reaction of dihydroxyaryl compounds with diarylcarbonate, wherein said melt polymerization is performed in the presence of a mixed catalyst composed of an oxygen (O) or sulfur (S) containing compound having lone-pair electrons and an alkali metal or alkaline earth metal salt in an appropriate ratio at a reduced temperature by accelerating a reaction rate to obtain high quality polycarbonates with higher than 15,000 g/mole of a viscosity average molecular weight and improved color.