| 摘要 |
Polycarbonate produced by melt condensation of a diaryl carbonate and a dihydric phenol in the presence of a basic catalyst to produce an intermediate polycarbonate composition is finished by quenching with both an alkyl tosylate quencher and phosphorous acid. The efficiency of quenching can be measured by UV retention. Surprisingly, although phosphorous acid alone has no impact on the UV retention, the combination of alkyl tosylate quenchers and phosphorous acid provides a significant improvement over the use of the alkyl tosylate quencher alone. Thus, the method of the invention permits a reduction in the amount of alkyl tosylate quencher used, and can achieve superior results which cannot be achieved even by increasing the alkyl tosylate levels. |
