Process and device for continuously treating with gases aqueous dispersions of polyvinyl chloride
AssigneeHoechst Aktiengesellschaft
InventorsChristoph Heinze, Franz Botsch, Horst Wolff
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Abstract
In aqueous dispersions on the basis of polyvinyl chloride the content of residual monomers is reduced by the countercurrent method by contacting the rapidly moved surface of the dispersion with secluded intensely mixed gas atmospheres in several successive chambers. To carry out the process a device is used which permits to obtain under mild conditions residual monomer contents of 10 ppm and therebelow.
Claims8
A process for continuously removing vinyl chloride monomer from an aqueous polymer dispersion whose polymer portion contains at least 50% by weight of polymerized vinyl chloride so as to obtain a residual vinyl chloride monomer content of 10 ppm or less, said process comprising the steps of passing the dispersion in one direction through the lower regions of at least two serially arranged chambers, passing a gas which does not react with the dispersion through the upper regions of said serially arranged chambers in a direction opposite to the passage of polymer dispersion so as to contact the upper surface of the dispersion in each chamber with said gas without passing said gas through said dispersion, and maintaining the upper surface of the dispersion in said chambers in motion in the direction of the boundry surface between the dispersion and the gas, said motion being radial relative to a point on the surface of said dispersion and having a speed of 0.3 to 10 m/sec.
Dependencies are inferred from the claim text.