Bayer Aktiengesellschaft

J&ouml;rgen Weinschenck

Paul Wagner

Winfried Joentgen

Torsten Groth

Ulrich Liesenfelder

Christian Kords

Clemens Casper

Thomas Elsner

J&uuml;rgen Heuser

Thomas Menzel

Klaus-Peter Heise

Klemens Kohlgr&uuml;ber

Frank D&ouml;bert

A process of evaporating a viscous polymer solution is described. The process includes: (a) providing a viscous polymer solution including at least 30 wt. % of solvents and monomers; (b) introducing the viscous polymer solution into a heated helix ( ), the heated helix having a vapor exit velocity of 200 to 300 m/s, (a film flow including a two-phase mixture of polymer melt, and solvent vapors and monomer vapors being formed within the helix); (c) forwarding the film flow from helix ( ) into a heated vapor separator ( ); (d) expanding the two-phase mixture of polymer melt, and solvent vapors and monomer vapors of the film flow within vapor separator ( ) at an absolute pressure of 10 mbar to 800 mbar, (a bottom product including a concentrated melt of the polymer is formed within the vapor separator); and (e) withdrawing the bottom product from vapor separator ( ). Each of the helix ( ) and vapor separator ( ) have a separate heating device, and each of heating device independently provides a temperature that is above the softening point of the polymer.

Method for isolating polymers from solutions

The invention relates to a method for carrying out polycondensation reactions, according to which the polycondensation of a monomeric starting material is carried out with external supply of heat in a reactor combination which has at least two stages and is composed of a pre-reactor and a high-viscosity reactor, where the low-molecular-weight elimination products produced are removed by evaporation. In the pre-reactor, the reaction product is concentrated to give a high-viscosity preliminary product. The high-viscosity preliminary product is then fed to the high-viscosity reactor, in which it reacts to completion with simultaneous introduction of thermal and mechanical energy and with a residence time of from 20 s to 60 min to give a polycondensation product.

Method for carrying out polycondensation reactions

Growing community of inventors

Krefeld, Germany

Jörgen Weinschenck

Growing community of inventors

Krefeld, Germany

J&ouml;rgen Weinschenck

Jörgen Weinschenck