Conversion of polycarbonate(s) based on bisphenol=A into partially crystalline granules - involves removing residual di:chloromethane solvent and continuously or batchwise expelling granules of specified solvent content

摘要

To convert polycarbonates (I) based on at least 80 mol.% bisphenol A, from soln. in CH2Cl2, with evapn. of the CH2Cl2, into partly crystalline, flowable granules, any remaining CH2Cl2 is rapidly evaporated and soln. of (I) is added to existing partly crystalline (I), with continuous or batchwise expulsion of granules having average CH2Cl2 content 21-45, (partic. 25-40), wt.%. Granules on which soln. of (I) is applied, are continuously comminuted and/or crushed to produce porosity. (I) is pressed through narrow gaps and/or sheared between metal pegs during addn. of (I) soln. and evapn. of CH2Cl2. ADVANTAGE - Residual CH2Cl2 is removed more quickly.