| abstract |
(57) [Summary] [Structure] The curl recovery rate after immersing a film having a curl by heat treatment in water is 70% or more, and 2 Immediately after being immersed in 5 ° C water for 30 minutes, the tensile Young's modulus is 2 A polyester film having a weight of 80 kg / mm 2 or more. [Effects] It has excellent transparency, water absorption, mechanical properties, and heat resistance, and when used as a support or cover layer for photographic light-sensitive materials, it can be made thinner than conventional triacetyl cellulose films, and It is possible to realize downsizing and high-speed unwinding. |