Abstract: 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.degree. and 300.degree. 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.degree. and 0.degree. 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.

Abstract: An improved method of coating glass bottles by flame spraying with pulverulent copolyamides which uses a copolyamide containing at least 30% by weight of laurolactam. The copolyamides, obtained by the hydrolytic polycondensation process are first subjected to a molecule-orienting treatment, then ground into powders at low temperatures, and these powders are sifted to a particle size distribution so that the proportion of powder having a particle size of between 30 and 100 microns is greater than 70 to 100%, and the proportion of powder having a particle size of less than 30 microns is 0 to 30%.

Abstract: Polyamide base powder coating material from a polyamide having an average of about 8 - 11 aliphatic carbon atoms per carbonamide group and containing about 0.2 to 5 percent by weight of carbonamide groups having n-alkoxymethyl groups based on the total number of carbonamide groups and about 0.01 - 2 percent by weight of acid catalysts.