| 摘要 |
PURPOSE:To provide a low-molecular weight polycarbonate molding material composed of a polycarbonate having a specific molecular weight, free from powdery polymer smaller than a specific particle diameter, and suitable as a molding material for optical disk having low silver-formation defects. CONSTITUTION:The objective molding material is produced by using granular polycarbonate having a molecular weight of 10,000-18,000 [e.g. a polycarbonate derived from 2,2-bis(4-hydroxyphenyl)propane (bisphenol A)] and having particle diameter of preferably >=2mm and decreasing the content of powdery polymer having an average particle diameter of <=0.5mm to <=2.0wt%. |
