| 摘要 |
PURPOSE:To make it possible to easily cut manually and to realize straight cutting in the direction of cutting, especially in the longitudinal direction by a method wherein tear propagation resistance in longitudinal direction and tear propagation resistance in the direction normal to the longitudinal direction are specified. CONSTITUTION:Biaxially oriented polyester film concerned is one, the tear propagation resistance alpha(g/mm) in longitudinal direction of which is 400g/mm or less and, at the same time, the tear propagation resistance beta(g/mm) in the direction normal to the longitudinal direction of which has the relationship of beta/alpha>=1.5. In this case, any polyester will do, provided that the film made thereof can be formed and polyethylene terephthalate, polytetramethylene terephthalate, polyethylene-o-oxybenzoate, poly-1,4-cyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalane dicarboxylate and the like are exampled. Thus, film, which is easily cut and has the direction of cutting in the longitudinal direction of the initial direction of orientation, can be obtained. |
