Method for carrying out polycondensation reactions

US6187898A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Paul Wagner · Mülheim an der Ruhr, DE
• Frank Dobert · Earlton, US
• Thomas Menzel · Hilten, DE
• Torsten Groth · Reinbek, DE
• Winfried Joentgen · Neunburg vorm Wald, DE
• Ulrich Liesenfelder · Bensberg, DE
• Jorgen Weinschenck · Krefeld, DE
• Klaus-Peter Heise · Bensberg, DE

Key dates

• Filing date: Aug 13, 1999
• Grant date: Feb 13, 2001
• Expiry date: Aug 13, 2019

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G73/0611
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

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.