| 摘要 |
PURPOSE:To extremely minimize impurity contents by specifying the contents of impurities to low mol.wt. components, unreacted bisphenols and methylene chloride. CONSTITUTION:All the contents of the impurities in polycarbonate are low. The content of the low mol.wt. components is confined to <=3wt.%, more preferably <=2wt.%, the content of the unreacted bisphenols to <=20ppm, more preferably <=10ppm, and the content of the methylene chloride to <=20ppm, more preferably <=15ppm. The adhesiveness of a disk substrate and a recording film is degraded if the content of the low mol.wt. component exceeds 3wt.% or the content of the unreacted bisphenols exceeds 20ppm; furthermore, the recording is more susceptible to corrosion and metallic molds receive corrosion at the time of molding and, therefore, the life of a stamper is shortened if the content of the methylene chloride exceeds 20ppm. The contents of the impurities are thereby extremely decreased and the high quality is obtd. |
