Polycarbonate for disc substrate.

摘要

Polycarbonate for production of disc substrates, a process for efficiently producing said polycarbonate, and a disc substrate made of said polycarbonate are disclosed. This polycarbonate has a low molecular weight polymer content of not more than 3% by weight, an unreacted bisphenol content of not more than 20 ppm, and a methylene chloride content of not more than 20 ppm, and can be obtained by extracting impurity-containing powdery polycarbonate with an organic solvent such as acetone and methyl ethyl ketone. This polycarbonate is particularly suitable for production of high quality disc substrates.