Two-step method for dehydrating plastic dispersions
AssigneeRoehm GmbH
InventorsHeinz Vetter, Hartmut Schikowsky, Werner Hoess
Life of this patent
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Abstract
The invention relates to a method for dehydrating a two-phase liquid mixture consisting of a thermoplastic synthetic melt phase and an aqueous phase, comprising the following steps: a) coagulation of the two-phase liquid mixture in a first extruder; b) dehydration of the coagulate in a twin screw extruder with a de-watering zone and screws working in an opposite direction; c) separation of constituents by degasifying. The inventive method is characterized in that a single screw extruder or a twin screw extruder with screws working in the same direction is used as a first extruder in step a).
Claims4
A process for dewatering a two-phase fluid mixture of a thermoplastic resin phase and a water phase by
- a) coagulating the two-phase fluid mixture in a first extruder which is a twin-screw extruder equipped with co-rotating screws,
- b) dewatering the coagulate in a twin-screw second extruder with counter-rotating screws and with a dewatering zone, and
- c) separating volatile constituents by degassing in a degassing extruder.
Dependencies are inferred from the claim text.