Process for the production of polyurethane particles

US6548619B2 · kind B2 · utility

Assignees

• Eckhard Weidner · DE
• Marcus Petermann · US
• Andreas Zilzer · DE

Inventors

• Alexander Pross · Bensberg, DE
• Heinz-Werner Lucas · Bensberg, DE
• Horst Stepanski · Leverkusen, DE
• Eckhardt Weidner · Bochum, DE
• Marcus Petermann · Bochum, DE
• Andreas Kilzer · Witten, DE

Key dates

• Filing date: Aug 10, 2001
• Grant date: Apr 15, 2003
• Expiry date: Aug 10, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08J2375/04
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

The present invention relates to a process for the production of particles from solutions or melts of heat-activatable polyurethanes byi) dissolving a compressible auxiliary agent at a pressure of between 50 and 1000 bar into a conveyable solution or melt of a heat-activatable polyurethane to obtain a mixture of polyurethane, compressible auxiliary agent and optionally solvent,ii) optionally adjusting of the temperature of the resulting mixture to a temperature of from 40° K below to 150° K above the crystallite melting point of the polyurethane,iii) expanding the mixture by means of an expansion device into a container, while adjusting the temperature in the container to at least 5° K below the softening temperature of the polyurethane to maintain the open jet particles in a form in which they do not agglomerate, andiv) separating the formed particles from the stream of decompressed compressible auxiliary agent and optionally solvent.