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Title:
PRODUCTION OF BASE FOR OPTICAL RECORDING MEDIUM
Document Type and Number:
Japanese Patent JPH0326532
Kind Code:
A
Abstract:

PURPOSE: To make it possible to suppress birefringence and to enhance productivity, by incorporating a specified phosphorous acid ester into a polycarbonate resin, and continuously extruding the resultant resin.

CONSTITUTION: A bis(hydroxyphenyl)alkane polycarbonate resin containing 0.005 to 0.5wt.% of a phosphorous acid ester of the formula and having a number average molecular weight of 18000 to 50000 is extruded to continuously produce a base. In the formula, each of R1 and R2 is an alkyl or aryl, and R3 is hydrogen, an alkyl or aryl. A Polycarbonate resin sheet extruded through a T-die 4 of an extruder 5 is pressed, in a softened state, by a rugged stamper surface of a forming roller 2 and a specular surface of a pressure roller 3, whereby signals representing the rugged stamper form are transferred successively to the surface of the resin base 1. The resin temperature is preferably 200 to 400°C, and the temperature of the forming roller 100 to 200°C. A base for an optical recording medium having excellent transparency and a low birefringence can be produced continuously with favorable productivity.


Inventors:
YOSHINO HITOSHI
Application Number:
JP16064489A
Publication Date:
February 05, 1991
Filing Date:
June 26, 1989
Export Citation:
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Assignee:
CANON KK
International Classes:
C08K5/524; B29D17/00; C08K3/00; C08L69/00; G11B7/26; B29K69/00; (IPC1-7): B29D17/00; B29K69/00; C08K5/524; C08L69/00; G11B7/26
Attorney, Agent or Firm:
Tokuhiro Watanabe



 
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