Patent ID: 8137817
Filing Date: 2012-03-20
Classification: B29C,B29K,Y10T

Abstract:
1. A film roll wound up of a polyamide based resin film 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, a final cutout portion is set up within 2 m from the winding start of film, and a sample cutout portion is set up in approximately every 100 m from the first sample cutout portion, the following requirements are satisfied: (1) when a maximum boiling water shrinkage percentage of each sample cut out from each of the cutout portions is measured, the maximum boiling water shrinkage percentage being the maximum value of boiling water shrinkage percentages in all directions, an average boiling water shrinkage percentage of the maximum boiling water shrinkage percentages is 3% to 6%, and a degree of variability in the maximum boiling water shrinkage percentages of all samples is within ±2% to ±10% relative to the average boiling water shrinkage percentage; (2) when a directional difference of boiling water shrinkage percentage of each sample cut out from each of the cutout portions is measured, the directional difference of boiling water shrinkage percentage being the difference between a boiling water shrinkage percentage in the direction of +45° to the longitudinal direction and a boiling water shrinkage percentage in the direction of −45° to the longitudinal direction in an absolute value, an average directional difference of boiling water shrinkage percentage which is the average of the directional differences of boiling water shrinkage percentage is 1.5% or less, and a degree of variability in the directional differences of boiling water shrinkage percentage of all samples is within ±2% to ±10% relative to the average directional difference of boiling water shrinkage percentage; (3) a degree of variability in the film thickness of a roll wound up over the entire length in the longitudinal direction is within ±2% to ±10% relative to the average thickness.