| 摘要 |
PROBLEM TO BE SOLVED: To enhance a sensitivity in the case of perforating and to provide an excellent uniformity of perforating by satisfying specific relationship between a density of a thermoplastic resin film and a noncrystal density of a thermoplastic resin composition. SOLUTION: The film is formed of a thermoplastic resin composition. As the resin, a polyester or the like is preferable. It is necessary that a density (d:g/cm<3> ) of the film and a noncrystal density (do:g/cm<3> ) of the composition for constituting the film satisfyn a formula I. If (d-do) is less than -0.6 g/cm<3> , a base sheet is easily curled, and hence not preferable. If it exceeds 0.02 g/cm<3> , an effect of improving a sensitivity is not sufficiently obtained. Preferably, it satisfies a formula II. If it falls within this range, a curl further scarcely occurs. More preferably, it satisfies a formula III. If it falls within this range, perforability is further improved. |
