POLYAMIDE RESINS AND PROCESSES FOR MOLDING THEM

摘要

Provided is a polyamide resin having high heat resistance , excellent moldability and excellent mechanical properties. The polyamide resin comprises a diamine unit containing 70 mol % or more of a xylylenediamine unit and a dicarboxylic acid unit containing 70 mol % or more of a straight chain aliphatic dicarboxylic acid unit, wherein the xylylenediamine unit is composed of 50 to 95 mol % of p-xylylenediamine and 50 to 5 mol % of m-xylylenediamine; the straight chain aliphatic dicarboxylic acid unit is composed of 50 to 100 mol % of adipic acid and 0 to less than 50 mol % of sebacic acid or other straight chain aliphatic dicarboxylic acids; the molar ratio of reacted diamine units to reacted dicarboxylic acid units (the number of moles of reacted diamine units / the number of moles of reacted dicarboxylic acid units) is less than 0.994; and the polyamide resin has a number average molecular weight of 10,000 to 25,000 and a melting point of 285 °C or more.