Chemische Werke Huls Aktiengesellschaft

Bernd Terwiesch

Karsten Flatau

Hermann Winter

Bernhard Hentschel

Peter Rauth

Karl-Heinz Schoenberg

Lothar Hinz

Hans Grosse-Wortmann

Residual vinyl chloride contents of aqueous polyvinyl chloride dispersions is reduced to less than 50 ppm by withdrawing steam and vinyl chloride contained in a boiling aqueous polyvinyl chloride dispersion at a temperature of 80.degree.-100.degree. C. and at a vaporization rate per minute of 0.006-0.2 kg. steam per kg. of polyvinyl chloride for a period of time from 3-60 minutes until a vinyl chloride content of less than 50 p.p.m. is achieved.

Process for the removal of vinyl chloride from polyvinyl chloride

Encrustations on reactor walls and associated equipment employed in the aqueous suspension polymerization of vinyl chloride and mixtures thereof with other monomers at 30.degree.-70.degree. C. are prevented by employing in the polymerization charge 0.0005 - 0.05% by weight of hydrogen peroxide, calculated on the monomer or monomers, preferably at a pH of at least 7.5, e.g., 7.5 - 8.5 when using a suspending agent which is sensitive to hydrolysis.

Process for preventing encrustations during the manufacture of polymers

The formation of polymer on the surfaces of the reactor equipment in the commercial production of polyvinyl chloride and copolymers thereof is avoided by employing equipment whose surfaces which contact the monomer are formed of substantially pure nickel.

Prevention of wall deposits during polyvinyl chloride polymerizations

Growing community of inventors

Marl, Germany

Bernd Terwiesch