Abstract: To provide a biaxially oriented polyamide-based resin film being excellent in laminate strength, pin-hole resistance under a low-temperature environment, impact resistance, and transparency, and which retains satisfactory a good external appearance even after being sterilized in hot water. A biaxially oriented polyamide-based resin film comprising a polyamide resin and 1 to 5% by mass of a polyamide-based block copolymer, wherein the polyamide-based block copolymer comprises a hard part including a residue of cyclic lactam having 4 to 10 carbon atoms, and a soft part including a residue of polyoxypropylene glycol or polyoxytetramethylene glycol having a weight average molecular weight of 500 to 3000, and the content X of the hard part and the content Y and the weight average molecular weight Mw of the soft part satisfy the following formulae (1) and (2): X+Y=100(parts by mass)??(1) 478.74×Mw?0.2989?Y?93(parts by mass)??(2).

Abstract: To provide a biaxially oriented polyamide-based resin film being excellent in laminate strength, pin-hole resistance under a low-temperature environment, impact resistance, and transparency, and which retains satisfactory a good external appearance even after being sterilized in hot water. A biaxially oriented polyamide-based resin film comprising a polyamide resin and 1 to 5% by mass of a polyamide-based block copolymer, wherein the polyamide-based block copolymer comprises a hard part including a residue of cyclic lactam having 4 to 10 carbon atoms, and a soft part including a residue of polyoxypropylene glycol or polyoxytetramethylene glycol having a weight average molecular weight of 500 to 3000, and the content X of the hard part and the content Y and the weight average molecular weight Mw of the soft part satisfy the following formulae (1) and (2): X+Y=100 (parts by mass) ??(1) 478.74×Mw?0.2989?Y?93 (parts by mass) ??(2).

Abstract: A hard foam formed from a carboxylic acid ester-based polymer having a ring structure, the hard foam being obtained by heating the carboxylic acid ester-based polymer having a ring structure to generate a gaseous organic acid from the carboxylic acid ester-based polymer, and foaming the heated carboxylic acid ester-based polymer with the gaseous organic acid, and a method for producing the same. The hard foam can be used as various heat insulating materials, various vibration isolators, various acoustic materials, various soundproof materials and the like. Therefore, the hard foam is expected to be used for automobile component materials, materials for airplanes, materials for the space field, materials for industries, materials for medical assistance, and the like.