Polycarbonate resin composition for use in the production of a substrate for an optical information medium
A polycarbonate resin composition for use in the production of a substrate for an optical information medium, comprising (A) an aromatic polycarbonate resin having a weight average molecular weight of from 13,000 to 18,000, wherein the aromatic polycarbonate resin (A) is produced by subjecting an aromatic dihydroxy compound and a carbonic diester to a transesterification reaction, and is substantially free of a chlorine atom; and (B) a partial ester obtained from a saturated aliphatic carboxylic acid having 10 to 30 carbon atoms and a di- to hexahydric alcohol, wherein the partial ester (B) has an acid value of from 2 to 20 mgKOH.
1. A polycarbonate resin composition for use in the production of a substrate for an optical information medium, comprising:
100 parts by weight of (A) an aromatic polycarbonate resin having a weight average molecular weight of from 13,000 to 18,000,
wherein said aromatic polycarbonate resin (A) is produced by subjecting an aromatic dihydroxy compound and a carbonic diester to a transesterification reaction, and is substantially free of a chlorine atom, and
0.01 to 0.1 part by weight of (B) a partial ester obtained from a saturated aliphatic carboxylic acid having 10 to 30 carbon atoms and a di- to hexahydric alcohol, said partial ester (B) having an acid value of from 2 to 20 mgKOH.
2. The polycarbonate resin composition according to claim 1 , wherein said aromatic polycarbonate resin (A) comprises a plurality of aromatic polycarbonate main chains, each comprising recurring units each independently represented by the following formula (1):
wherein Ar represents a divalent C 5 -C 200 aromatic group,
wherein said plurality of aromatic polycarbonate main chains collectively contain therein at least one heterounit,
said heterounit being represented by the following formula (2):
wherein Ar′ represents a trivalent C 5 -C 200 aromatic group, and X represents a polycarbonate chain having recurring units each represented by the formula
wherein
Ar is as defined above and having a molecular weight of from 214 to 6,000, and
wherein, when said polycarbonate main chains contain a plurality of heterounits, the heterounits are the same or different,
the amount of said heterounit (2) being from 0.03 to 0.20 mole %, based on the total molar amount of said recurring units (1).
3. The polycarbonate resin composition according to claim 1 or 2 , wherein said partial ester (B) is at least one member selected from the group consisting of glycerol monostearate and glycerol monopalmitate.
4. The polycarbonate resin composition according to claim 1 or 2 , which is a substrate for an optical information medium, said substrate being produced by injection molding.