POLYAMIDE RESIN COMPOSITION EXCELLENT IN LASER MARKABILITY

摘要

PURPOSE: To obtain a polyamide resin composition excellent in laser markability and capable of being furnished with a mark with high contrast by using a polyamide resin containing a suitable amount of water. CONSTITUTION: This resin omposition comprises 100 pts.wt. polyamide resin having a water content of 0.06-12wt.% and 0.001-5 pts.wt. carbon. Examples of the polyamide resins used include a ring-opening polymer of a lactam, a polycondensate of an aminocarboxylic acid and a polycondensate of a dibasic acid with a diamine. Nylon 46, nylon 6 and nylon 66 are particularly desirable. The water content is adjusted so that it has a suitable value before or after molding. It is desirable that the carbon is the one having high thermal conductivity. Desirable examples of processes for mixing the components include the one comprising homogenizing them by mixing a part or all of them at one time or separately with a mixer and the one comprising uniformly dispersing them by previously dry-blending them and melt-kneading the dry blend with a heated extruder.