| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the trouble such as contraction or release caused by heat shrinkage, in a biaxially oriented polyester film of which the heat shrinkage factor under an air atmosphere of specific temp. is a specific value or less in one direction, by thermally bonding the film to an aluminum plate and subjecting the obtained laminate to non-crystal orientation treatment before using the same in squeezing-handling processing. SOLUTION: A biaxially oriented polyester film is formed by the so-called sequential biaxial stretching system successively stretching a non-stretched sheet obtained by a usual melt extrusion method or co-extrusion method longitudinally and laterally and subjecting the stretched one to thermal fixing and slackening treatment. In the slackening treatment and thermal fixing, a heat shrinkage factor at 220 deg.C is set to 10% or less at least in one direction. Biaxially oriented polyester films 2, 3 are bonded to an aluminum plate 1 regulated to predetermined temp. in a preheating hot air oven for temporary adhesion under pressure by pressure bonding rolls 4, 5 for temporary heat adhesion to execute temporary adhesion. Next, the bonded matter is subjected to non- crystallization treatment by a furnace 7 for non-crystallization treatment and subsequently used in squeezing-handling processing. |
