| 摘要 |
PURPOSE:To enable the title sealant film to have favorable sealing properties, high sealing strength, excellent film strength, low thermal shrink properties, excellent dimensional stability, generate no creases at the time of heat sealing and make a mult-layer film into a thin film, by a method wherein since the title film is comprised of resin consisting mainly of linear low density polyethylene, stretched at least three times in a lateral direction and an area shrinkage factor and a shrinkage ratio between a longitudinal and lateral directions are within a specific range. CONSTITUTION:Raw sealant film is obtained by a method wherein raw fabric which is substantially unstretched is molded of resin consisting mainly of linear low density polyethylene, the raw fabric is stretched biaxially and then heat-treated the same. It is good to make that draw ratio is at least three times and less than 8 times and the product of draw ratios of biaxial directions is at least 9 times and less than 50 times from view points of biaxial stretchability and physical properties of a film to be obtained. An area shrinkage factor is not exceeding 30% at 100 deg.C and a stretching temperature, the draw ratio and a heat treatment condition are combined by selecting them appropriately. With this construction, it is prepared that a shrinkage ratio of a longitudinal direction : lateral direction or the lateral direction : longitudinal direction of a biaxially stretched film becomes within a range of 0.5-2.0. |
