Patent Number: 6,166,167

Title: Polycarbonate resin for substrate of optical recording medium

Abstract: A polycarbonate resin obtained by polymerizing an aromatic diol and a carbonate-forming compound using a monophenolic compound as a molecular weight modifier, wherein said polycarbonate resin contains from 0.2 to 2% by weight of a low-molecular weight compound represented by formula (I): ##STR1## wherein R.sup.1 represents an aromatic diol residue; and R.sup.2 represents a monophenolic compound residue, and wherein said polycarbonate resin provides less amount of low-molecular weight volatile matters even when heated or injection-molded. When heated at 350.degree. C. under reduced pressure of 1 mmHg for 20 minutes, the proportion of the low-molecular weight compound of formula (I) which volatilizes is not more than 0.2% by weight based on the weight of said low-molecular weight compound of formula (I) present in the polycarbonate resin. When heated at 400.degree. C. under reduced pressure of 1 mmHg for 30 minutes, the proportion of the low-molecular weight compound of formula (I) which volatilizes is not more than 2% by weight based on the low-molecular weight compound of formula (I) present in the polycarbonate resin.

Inventors: Miyamoto; Masaaki (Fukuoka, JP), Ueda; Motonori (Okayama, JP)

Assignee: Mitsubishi Chemical Corporation

International Classification: C08G 64/24 (20060101); C08G 64/00 (20060101); G11B 7/253 (20060101); G11B 7/24 (20060101); C08G 064/00 ()

Expiration Date: 12/26/2017