Abstract: An oriented splittable film which contains nylon and meta-xylylene adipamide at a weight ratio of 40-85:15-60 and which was oriented with a magnification above 2.8 times in both directions of MD and TD. Examples of nylon include nylon 66, nylon 6-66 copolymer and so on. Under this manufacturing method for an oriented splittable film, when a raw film is heated in a biaxially orienting process, such as the tubular method, the heating temperature at the side part of the film, in the direction of film width,,when folding the bubbles, is controlled along the circumference direction of the bubbles so that it is lower than the heating temperature of the part of the film which is used later as a product.

Abstract: An oriented splittable film which contains nylon and meta-xylene adipamide at a weight ratio of 40-85:15-60 and which was oriented with a magnification above 2.8 times in both directions of MD and TD. Examples of nylon include nylon 66, nylon 6-66 copolymer and so on. Under this manufacturing method for an oriented splittable film, when a raw film is heated in a biaxially orienting process, such as the tubular method, the heating temperature at the side part of the film, in the direction of film width, when folding the bubbles, is controlled along the circumference direction of the bubbles so that it is lower than the heating temperature of the part of the film which is used later as a product. The heat treatment process for these films includes a first heat treatment step implemented for films at temperatures between 120 degrees C. and 190 degrees C. based on the tubular method or tenter method and a second heat treatment step implemented for films at temperatures between 190 degrees C. and 220 degrees C.

Abstract: A method of and an apparatus for biaxially orienting a crystalline thermoplastic resin film and subsequently thermally processing the film with first and second heating devices, in which the temperatures of respective heaters for biaxially orienting the film are separately controlled, the first heating device being operated by a tubular method or a tenter method, and the second heating device being operated under a tenter method and above the temperature in the first heating device, whereby a melting and sticking of the film is prevented and the bowing ratio is decreased.

Abstract: The invention relates to processes for producing biaxially oriented single-layered and multilayered films. The biaxially oriented single-layered film receives stresses in the range of 500 kg/cm.sup.2 to 1500 kg/cm.sup.2 each in the machine and transverse directions of the film. The multilayered film receives stresses in the range of 300 kg/cm.sup.2 to 1250 kg/cm.sup.2 each in the machine and transverse directions of the film. Thus, the molding stability in biaxial orientation of a nylon film is improved and the thickness accuracy of a resulting film is improved.