To obtain the subject film satisfying pinhole resistance and excellent in tension or curling in post-treatment such as boiling or retorting by forming a polyurethane resin layer to the single surface of a biaxially stretched polyamide film specified in hot water shrinkage factor.
A base material film 1 may be composed only of one biaxially stretched polyamide film 1a having a shrinkage factor range but a laminated film obtained by laminating a second biaxially stretched polyamide film 1b having a shrinkage factor lower than that of this film to a first biaxially stretched polyamide film 1a having a hot water shrinkage factor range of 1.0-5.0% is also used. A polyurethane resin layer 2 is formed on at least the single surface of the base material film 1 in a coating amt. of 0.01-0.5 g/m2 as easy adhesive coating treatment. Even when the polyurethane resin layers are formed on both surfaces of the base material film 1, this coating amt. is a value only of the single surface.
ONISHI MASAHARU
TATSUI MIYUKI
Next Patent: BIAXIALLY ORIENTED POLYAMIDE FILM HAVING EASILY ADHESIVE PROPERTIES AND PRODUCTION THEREOF