Polyamides exhibit excellent mechanical properties upon addition of reinforcing materials represented by glass fibers, fillers such as inorganic fillers, and additives and, therefore, have hitherto been used in many fields such as automobile, electrical and electronics, and civil engineering and construction. In recent years, various carbon fiber-reinforced materials with light weight and high rigidity have been also proposed as metal substitute materials (JP 2006-001965 A). Further, a long fiber-reinforced polyamide composition comprising a polyamide and a specific reinforcing fiber roving to enhance mechanical strength at a higher temperature has also been proposed (JP 2010-202759 A).
Even the known materials above could not improve degradation of physical properties due to the water-absorbing property of polyamide and water absorption, which has been a problem for a long period of time. Further, the long fiber-reinforced polyamide composition as shown in JP '759 has been disadvantageous in that an injection-molded product therefrom has a poor appearance such as a protruding welding part, though exhibiting excellent mechanical properties as compared to common fiber-reinforced polyamides produced from a reinforcing fiber and a thermoplastic resin using a twin-screw extruder.
It could therefore be helpful to provide a resin composition having excellent moldability, undergoes a decrease in rigidity and strength upon water absorption, which is a disadvantage of polyamide, to a small extent, and has excellent appearance, a pellet thereof, and a molded product thereof.
USPTO Backgrounds
USPTO Backgrounds