Removing residual vinyl chloride monomer from polymerisation system - followed by adding water contg. nonionic surfactant to polymer

摘要

(Co)polymers prepd. by bulk polymsn. of vinyl chloride are freed from residual monomer by bringing the polymsn. pressure down to below an absolute pressure of 0.16 bar and keeping the temp. at at least 70 deg.C, but lower than the degradation temp. of the polymer and maintaining these conditions of temp. and pressure until removal of the monomer is over, the polymer compsn. being agitated during the process, and being contacted with water when the residual vinyl chloride content reaches a value below 2000 mg/ kg. This process is now improved by adding a nonionic surfactant to the water. The improvement gives a (co)polymer whose mixt. with a (co)polymer of vinyl chloride from a different source, prepd. by bulk or suspension polymsn., has improved flow properties and therefore does not cause transport problems in a pipe conveying plant.