Process for the production of polyurethane particles

• Main Authors: Pross, Alexander, Lucas, Heinz-Werner, Stepanski, Horst, Weidner, Eckhardt, Petermann, Marcus, Kilzer, Andreas
• Format: Patent
• Language: English
• Published: 15.04.2003

1. Field of the Invention 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.