Purification of a polycarbonate prepd. by a two phase boundary process, in order to remove salts, monomers, catalyst etc.

摘要

Method for purifying (co)polycarbonate or polyestercarbonate, pref. polycarbonate, prepd. by a two-phase boundary layer process, in order to remove impurities from the prodn. process, comprises the following steps : (1) the prodn. process mixt. is sepd. into an organic phase contg. polycarbonate and an aq. phase contg. salts ; (2) the organic phase is mixed with dilute mineral acid to remove any catalyst and then it is washed ; (3) the aq. phase is sepd from the two-phase mixt. from step (2) and the organic phase is opt. passed over one or more coalescers to remove any salt-contg. water ; (4) the organic phase is washed with water or opt. dilute acid again in at least one washing and sepn. step ; and (5) the aq. phase is removed from the organic phase which is then opt. passed over one or more coalescers to remove water. All of the coalescers are packed with a material that has strongly hydrophobic surfaces and at least one coalescer is used for a phase sepn. step.