| abstract |
(57) [Summary] [Structure] 60 to 100 mol% of dicarboxylic acid units are composed of 2,6-naphthalenedicarboxylic acid units, and 60 to 100 mol% of diamine units are composed of 1,9-nonanediamine units (ND units). Or the diamine unit is an ND unit and a 2-methyl-1,8-octanediamine unit (MOD unit) (provided that the ND unit: A polyamide (B) having a molar ratio of MOD units = 60: 40 to 99: 1) and an intrinsic viscosity [η] measured in concentrated sulfuric acid at 30 ° C. of 0.4 to 3.0 dl / g ( However, polyamide (A) has 10% or more of the terminal groups sealed), a polyamide composition comprising 100 parts by weight of the polyamide and 0.1 to 200 parts by weight of a filler, or these polyamides or A molded product made of a polyamide composition. [Effect] Polyamides and polyamide compositions are excellent in mechanical properties, heat resistance, thermal decomposition resistance and low water absorption, and also in performances such as hot water resistance and chemical resistance. Further, the molded product can retain the various properties of the above polyamide and the polyamide composition as they are. |