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:
Dec. 29, 1998
Filed:
Jun. 25, 1997
Applicant:
Inventors:
Chun-Shan Wang, Tainan, TW;
Jen-Tau Gu, Tainan, TW;
Assignee:
National Science Council, , TW;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C08G / ;
U.S. Cl.
CPC ...
528196 ; 528198 ; 558268 ;
Abstract
A process for producing a polycarbonate including melt polycondensing an aromatic dihydroxy compound and a carbonic acid diester in the presence of a phosphonium borohydride catalyst(I), ##STR1## wherein R is a straight-chain or branched alkyl group, or ##STR2## wherein each of R.sub.1, R.sub.2, and R.sub.3, independently is a C.sub.1 .about.C.sub.4 alkyl group. A colorless, transparent polycarbonate having a high molecular weight is obtained by using the phosphonium borohydride compound (I) as a transesterification catalyst, which may be used alone or incorporated with boric acid or a hindered phenol antioxidant.