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. 26, 1996
Filed:
Sep. 12, 1995
Masuzo Yokoyama, Mie, JP;
Junji Takano, Mie, JP;
Masami Hasegawa, Mie, JP;
Yukiko Tatsukawa, Mie, JP;
Mitsubishi Chemical Corporation, Tokyo, JP;
Abstract
A process for producing an aromatic polycarbonate is described, which comprises melt-polycondensing an aromatic diol compound with a diaryl carbonate compound in the presence of an interesterification catalyst, said interesterification catalyst comprising a quaternary phosphonium salt compound represented by formula (II): ##STR1## wherein R.sup.3, R.sup.4, R.sup.5, and R.sup.6 each independently represent an alkyl group having 1 to 12 carbon atoms, an aryl group, an aralkyl group, or a cycloalkyl group, and X.sup.l- is an anion selected from the group consisting of a carbonate ion, a phosphate ion, and a tetrahydroxyboron ion, with the letter l indicating the valency of X.