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. 01, 1992
Filed:
Jan. 08, 1991
Applicant:
Inventors:
Mitsuru Ueda, Yamagata, JP;
Tatsuya Kanno, Hyogo, JP;
Yoshihiro Iguchi, Hyogo, JP;
Yasuhiro Oshino, Hyogo, JP;
Assignee:
Daicel Chemical Industries, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C08G / ;
U.S. Cl.
CPC ...
528199 ; 528196 ; 528198 ; 528204 ;
Abstract
A polycarbonate is produced by melt-polycondensing a dihydric hydroxy compound and a bisarylcarbonate in the presence of 4-(4-methyl-1-piperidinyl)-pyridine, or a salt thereof, as a catalyst. The process of the invention eliminates the use of poisonous phosgene, prevents chloride ions from being incorporated into the product polycarbonate and remains in the reaction system longer to enable the preparation of high-molecular weight polycarbonates.