Method of concurrently-biaxially drawing polyvinyl alcohol film

A process for preparing a concurrently-biaxially drawn polyvinyl alcohol film, comprising the steps of:

• (a) fabricating a molten, hydrated polyvinyl alcohol into a film;
• (b) drying said film while preventing orientation of the film thereby obtaining a substrate film which is in a substantially non-oriented state and which has a water content of 3 to 20 wt. %;
• (c) coating said dried film on at least one surface with an aqueous dispersion of a macromolecular compound thereby forming a coated film wherein the film substrate has an average water content of 5 to 30 wt. % as a result of water permeation into the substrate film from said coating, the average water content of said substrate film increasing by 2 to 10 wt. % as a result of said water permeation;
• (d) concurrently-biaxially drawing said coated film to achieve an area elongation of 600 to 1300%;
• (e) heat treating said drawn film to relieve stress in said film and to dry said film to a water content of less than 3 wt.%;
• and
• (f) continuing the heat treating of said dried film at a temperature greater than 160.degree. C. but less than the decomposition temperature to achieve the film product.