Patent ID: 8062740

Claim:
A film roll wound up of a polyamide based mixed resin film composed of a mixed resin consisting of polyamide based resin and thermoplastic elastomer in a width of 0.2 m or more, 3.0 m or less, and a length of 300 m or more, 30000 m or less, wherein when a first sample cutout portion is set up within 2 m from the winding end of film and a final cutout portion is set up within 2 m from the winding start of film, and wherein when a sample cutout portion is set up in approximately every 100 m from the first sample cutout portion, the following requirements (1) and (2) are satisfied: (1) when the content of thermoplastic elastomer constituent is measured for each sample cut out from each of the cutout portions, and the average content rate which is the average value of these content rates is computed, the degree of variability of the content of thermoplastic elastomer constituent of all the samples is within the ±10% range with respect to the average content rate, and (2) the degree of variability of thickness throughout the full length in the longitudinal direction of a wound-up roll is within the range of ±2% to ±10% with respect to the average thickness; wherein the thermoplastic elastomer of the polyamide based mixed resin film wound up is selected from polyamide based elastomers of block or random copolymers of polyamide based resin and polytetramethylene glycol or polyethylene glycol; and wherein the amount of the thermoplastic elastomer of the polyamide based mixed resin film wound up is 1% by weight or more and 6% by weight or less.