METHOD FOR MANUFACTURING POLYAMIDE POWDER 12 WITH A HIGH MELTING POINT

摘要

The present invention relates to a process for the preparation of polyamide 12 powder by anionic polymerization in which the lauryllactam is polymerized in solution in a solvent, the solvent being a solvent for the lactam and the polyamide 12 powder being insoluble in this solvent, in the presence of a catalyst and an activator, in the presence of a finely divided organic or inorganic filler, the proportion of this filler being between 0.2 and 1.5 g per 1000 g of lauryllactam, in the presence of a amide of formula R1-NH-CO-R2 in which R1 may be replaced by a radical R3-CO-NH- or R3-O- and in which R1, R2, R3 denote an aryl, alkyl or cycloalkyl radical.The temperature of The melting of the polyamide powder 12 is at least 180 ° C. and advantageously 183 +/- 1 ° C. (first heating temperature measured by DSC, abbreviation of Differential Scanning Calorimetry). They have an average size of between 15 and 100 m and advantageously between 25 and 60 m. The process can be carried out in a stirred reactor provided with a heating device by a double jacket or a coil, a drainage system such as a bottom valve and a reagent introduction device swept with dry nitrogen. The present invention also relates to a process for manufacturing polyamide 12 articles by agglomeration of melting powders using radiation, the powders having been obtained according to the process mentioned above.