Hoechst Aktiengesellschaft

Christoph Heinze

Kasimir Ruchlak

Horst Wolff

Franz Botsch

Rolf Kranzle

Hermann Scheibler

Holm Steude

Paul Kastner

An apparatus known per se for the thermal treatment of a mixture of solids and gases, comprising a vessel having an axially symmetrical interior, which vessel has in the lower part and in the upper part in each case at least one tangentially arranged opening, in the interior of the vessel at least one annular baffle tightly sealing to the vessel wall being arranged between the two openings, and the lower part of the vessel having a smaller diameter, is operated or is designed so that in the lower part a high radial velocity and short residence time prevail and in the upper part a low radial velocity and long residence time prevail.

Process and apparatus for thermal treatment of a mixture of solid

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.

Process and device for continuously treating with gases aqueous

Polymer dispersions are subject to a spray treatment to reduce the monomer content thereof. The dispersions are sprayed against the wall of the vessel by means of at least one spray nozzle. The residual monomer content of polymer dispersions is further reduced by spraying them in at least two series connected vessels, conducting the escaping gaseous constituents in one direction and the dispersion in opposite direction from one vessel to the next. The process is little liable to troubles and ensures a very effective monomer removal without thermal damage of the polymer.

Process for the manufacture of vinyl chloride polymer dispersions with a

A continuous process and an apparatus for the polymerization of vinyl chloride in aqueous emulsion wherein the liquid reaction mixture is fed into the lower part of a vertical, cylindrical vessel, the liquid level in the vessel is adjusted to at most 97% of the total interior height of the vessel, the reaction mixture is stirred with a stirrer which is totally immersed in the liquid and extends over 15 to 60% of the total interior height of the vessel and the produced polymer emulsion is laterally discharged from the upper part of the vessel.

Process and apparatus for the continuous production of vinyl chloride

.alpha.-Ethylenically unsaturated monomers are polymerized in aqueous media in a vessel with electrically conductive inner surface, in which partial areas of the inner surface covered by liquid are electrically insulated from the remaining surface areas and conductively connected therewith by an external source of current. In this manner the formation of deposits on the wall of vessel is hindered or suppressed.

Process and apparatus for polymerizing .alpha.-ethylenically unsaturated

Mixtures of finely divided solids and gases are subjected to a thermal treatment by feeding the optionally heated gas tangentially into the lower section of an axially symmetrical vessel, adding the solid to the gas at the latest in the vessel, heating or cooling the mixture of solid and gas in the vessel through the wall thereof and discharging the mixture in the upper section of the vessel. The gas/solid mixture is conducted in the vessel in upward direction in at least two annular flows substantially closed in themselves and in horizontal position one above the other, the transport of the solid from one annular flow to the adjacent overlaying annular flow taking place in a concentric inner zone of the annular flows. The device used is provided with a jacket with heating or cooling means over at least part thereof, at least one tangential inlet and outlet in the lower and upper part of the vessel and in the interior between the inlet and outlet at least one annular baffle plate is closely fitted on the wall of the vessel.

Process and device for the thermal treatment of a mixture of finely

The present invention is related to the process of concentrating K-polymer-latices by ultra filtration carried out by means of a semi-permeable membrane made of a synthetic polymer having a determined molecular weight, comprising that the membrane is pretreated with an emulsifier solution prior to ultra filtration. This operation substantially prevents the formation of solid matter deposits on the membrane.

Process for concentrating latices

Pulverulent polyvinyl chloride molding compositions capable of being sintered are produced using as emulsifier an alkyl-aryl or alkyl-sulfonic acid or a mixture thereof. Prior to or during polymerization 20 to 80 % of the emulsifier are added, optionally together with other auxiliaries, and the balance is applied to the separated polymer. The molding compositions are especially suitable for the manufacture of separating plates for electric cells.

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Burghausen, Germany

Christoph Heinze