Patent ID: 8232333

Claim:
A process for preparing an ultrafine powder based on a polyamide comprising preparing a suspension by suspending inorganic particles in an alcoholic medium with introduction of an energy input of greater than 1000 kJ/m 3 , contacting the polyamide having a relative solution viscosity η rel in a range from 1.5 to 2.0, measured in a 0.5% m-cresol solution at 25° C., with the suspension under the action of pressure and/or temperature to generate an at least partial solution, and then precipitating the polyamide from the at least partial solution, wherein the suspension is prepared by, prior to introduction of an energy input of greater than 1000 kJ/m 3 , forming a presuspension of the inorganic particles in the alcoholic medium with introduction of an energy input of less than 1000 kJ/m 3 , dividing the presuspension into at least two substreams, these substreams are placed under a pressure of at least 500 bar in a high-energy mill, decompressed through a nozzle and allowed to meet one another in a gas-or liquid-filled reaction chamber, and high-energy grinding is optionally repeated at least once.