NOVELTY - A stretched nylon film comprises nylon resin as raw material. The nylon film is subjected to tension test along 4 directions including moving direction, direction orthogonal to the moving direction, 45 degrees direction, and 135 degrees direction, and stress-strain curve is obtained. The film has elasticity modulus of 1000-3800 MPa along 4 directions, tensile stress ( sigma 2) in limit of proportionality of 40-100 MPa or less along 4 directions, and stress ratio of tensile stress ( sigma 1) when strain is set to 0.5 and tensile stress ( sigma 2) in limit of proportionality of 4 or less along 4 directions.    USE - Stretched nylon film is used for multilayer film for cold molding for forming packaging material, and battery (all claimed) e.g. lithium cell mounted in electric vehicle, tablet-type terminal device and smartphone. The packaging material is used as press-through packaging material in pharmaceutical field, refill wrapping material for liquid detergent, and foodstuff packaging material.    ADVANTAGE - The stretched nylon film suppresses springback phenomenon during cold molding, and has excellent pinhole-proof characteristics and deep-draw moldability.    DETAILED DESCRIPTION - A stretched nylon film comprises nylon resin as raw material. The nylon film is subjected to tension test along 4 directions including moving direction, direction orthogonal to the moving direction, 45 degrees direction, and 135 degrees direction with sample width of 15 mm, gage length of 50 mm and tensile velocity of 100 mm/minute, and stress-strain curve is obtained. The film has elasticity modulus of 1000-3800 MPa along 4 directions, tensile stress ( sigma 2) in limit of proportionality of 40-100 MPa or less along 4 directions, and stress ratio of tensile stress ( sigma 1) when strain is set to 0.5 and tensile stress ( sigma 2) in limit of proportionality of 4 or less along 4 directions. INDEPENDENT CLAIMS are included for the following:    (1) multilayer film, which is obtained by laminating stretched nylon film;    (2) battery, which has multilayer film and battery main component. The multilayer film is molded such that battery main component is covered and surface of sealant layer of the multilayer film is on surface of battery main component; and    (3) manufacture of stretched nylon film, which involves molding raw material into raw film, stretching the raw film by tubular-type stretched method, heat-processing and heat-setting the film.