VERFAHREN ZUR HERSTELLUNG VON PULVERFOERMIGEN BESCHICHTUNGSMITTELN ZUR BESCHICHTUNG VON METALLISCHEN GEGENSTAENDEN NACH DEM SCHMELZUEBERZUGSVERFAHREN AUF DER BASIS VON POLYLAURINLACTAMPULVER

摘要

A process for preparing coating powders based on polylaurolactam for the vitrification coating process beginning with polylaurolactam granulates obtained by polymerizing laurolactam under internal pressure in the presence of 2 to 10% by wt. of water and 0.3 to 0.7% by wt. of phosphoric acid at temperatures between 265 DEG and 300 DEG C., in the absence of chain stabilizers, and which have a relative viscosity of between 1.50 and 1.80. After precooling to temperatures between -50 DEG and 0 DEG C., the granulates are ground and then graded. Extraction with methanol or ethanol is carried out prior to grinding or grading. Pigments are added to the monomerous laurolactam or to the polylaurolactam in the molten state prior to granulation. The powders are especially well suited to manufacture colored powders by the dry-blend process.