METHOD OF MANUFACTURE OF A LOW MOLECULAR WEIGHT POLYAMIDE AND USE THEREOF

摘要

The present invention relates to a method of preparation of a homopolymer polyamide powder having inherent viscosity of < 0.7 by anionic polymerization wherein a lactam is polymerized in solution in a solvent, said solvent being a solvent for the lactam and said polyamide powder being insoluble in this solvent, said method taking place: in the presence of a catalyst and an activator, in the presence of an amide and with: a mass ratio (lactam/amide) of less than 28; a mass ratio (lactam/catalyst) of less than 450; and a mass ratio (activator/amide) of greater than 1.25. The powder particles have mean size of between 1 and 300 µm, preferably between 1 and 100 µm, and viscosity when melted at 200 °C that is stable and less than or equal to 200 Pa.s. The present invention also relates to use of the powder thus prepared in compounds with metallic powders, intended for manufacture of composite parts by various processes (injection, compression, extrusion, sintering) to make for example plastomagnets, parts with very high magnetic performance or small metal parts.