| 摘要 |
<p>This invention is concerned with a process of preparing a polycarbonate from phosgene and a bisphenol by two-step polycondensation, accompnied by the recycling of unreacted bisphenol. The two-step polycondensation consists of prepolycondensation whereby polycarbonate olygomer is formed from phosgene and a bisphenol and main polycondensation whereby an intended polymer is formed from said polycarbonate olygomer produced by said prepolycondensation. Besides automatic optimum control of the feeding of phosgene and bisphenol to the prepolycondensation system, the bisphenol including the recycled bisphenol from the main polycondensation system, is conducted by means of a feed control system comprising at least one of automatic analyzers for determining the chloroformate end of said polycarbonate olygomer formed in the prepolycondensation system and for determining the remaining unreacted bisphenol in the polycondensation product formed in the main polycondensation system, respectively, and valves for the feeding of phosgene and the bisphenol, respectively, to the prepolycondensation system and automatically cotrolled in accordance with data obtained by said automatic analyzers.</p> |
