METHOD FOR PRODUCING POLYURETHANE PARTICLES

• Main Authors: WEIDNER, ECKHARDT, PROSS, ALEXANDER, STEPANSKI, HORST, LUCAS, HEINZ-WERNER, PETERMANN, MARCUS, KILZER, ANDREAS
• Format: Patent
• Language: English; French; German
• Published: 14.05.2003
• Edition: 7
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOSITIONS BASED THEREON; GENERAL PROCESSES OF COMPOUNDING; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR PREPARATION OR CHEMICAL WORKING-UP; THEIR RELEVANT APPARATUS; TRANSPORTING; WORKING-UP

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.