Basf Aktiengesellschaft

Basf Se Corporation

Horst Papenfuss

Christoph Bahr

Ruediger Krech

Sven Lawrenz

Guenter Scholz

Torben Kaminsky

Marian Mours

Hartmut Giesker

Ulrich Stich

A pipe switch having a setting system, a housing and a closure element. The housing includes an inner wall in which a feed opening and at least two discharge openings are provided. The position of the closure element is rotatably changeable relative to the discharge openings. The setting system including a control and a drive controls the closure element such that a plurality of positions of the closure element relative to the discharge openings are realized accordingly. The closure element may be in the form of a slide or a two-part element having flaps. The setting system in cooperation with the closure system provides the plurality of positions of the closure element relative to the discharge openings, in each of which the sum of the cross-sectional areas of a first and of a second discharge opening not covered by the closure element is substantially constant.

Pipe switch with metering function

The present invention relates to a process for the continuous production of thermoplastically processable polyurethane elastomers, by metering a polyisocyanate (A), a proportion of 1-80 equivalent%, based on the isocyanate group content of the polyisocyanate (A), of a compound (B) having an average of at 1.8-3.0 hydrogen atoms having Zerewitinoff activity, with an average molar mass of 450-5000 g/mol, and a proportion of 12-99 equivalent%, based on the isocyanate group content of the polyisocyanate (A), of a chain extender (C), into a self-cleaning twin-screw extruder whose diameter is 32-62 mm, which is operated at shear rates above 6000 sand residence times of 1-20 seconds, and then bringing the mixture from the self-cleaning twin-screw extruder into a second apparatus in order to complete the reaction.

Method for the continuous production of thermoplastically-processable polyurethane elastomers

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Stemwede-Haldem, Germany

Horst Papenfuss