| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical disk substrate attaining accurate transfer of pits, ensuring a low error rate and less liable to warp by moisture absorption with polycarbonate resin from 2,2-bis(3-methyl-4-hydroxyphenyl)propane. SOLUTION: This optical disk substrate is formed with polycarbonate resin obtd. by allowing a carbonate precursor to react with dihydric phenol, mainly 2,2-bis(3-methyl-4-hydroxyphenyl)propane. The specific viscosity of the polycarbonate resin is 0.2-0.4. When the resin is dissolved in methylene chloride, the number of undissolved particles each having >=0.5μm diameter measured in the resultant soln. is <=25,000 per 1g of the resin and the number of undissolved particles each having >=1μm diameter is <=500. The resin has <=0.2wt.% water absorption. |
