| abstract |
In view of the problem of conventional technique, the objection of the present invention is providing a white polyester film having both high reflecting rate and high masking ability, and the film would not be torn easily as well as has high productivity. The present invention is accomplished by means of a white polyester film having pore inside, in which comprising a layer composed of resin consisting of polyester resin and cyclic olefin copolymeric resin, and the pore rate in the cross section of the layer is more than 25% and 75% or less, and number average particle diameter of the cyclic olefin copolymeric resin in the film is 0. 1 μ m or more and 3 μ m or less. |