Stretched film having independent voids and method for producing the same

Abstract

It is an object of the present invention to provide a stretched film which is light and has improved mechanical properties inherent in stretched film. The stretched film of the present invention, containing the independent voids, is the one obtained by treating the as-stretched film to form the independent voids therein, these voids being formed by the flaky layers which keep characteristics of the as-stretched film. These independent voids have a thickness of, e.g., 10 to 500 μm on the two-dimensional plane and 1 to 250 μm in the thickness direction, and the film has a total thickness of 5 to 2000 μm thick. The stretched film may be coated with surface layers on both sides, thickness of each surface layer being 5 to 20% of the total thickness.

Dependencies are inferred from the claim text.