To provide a biaxially oriented polyamide film having easily adhesive properties and excellent solvent-resistance through a sequential biaxial orientation method.
After a substantially non predeterminedly shaped and oriented polyamide film that has not yet been stretched is longitudinally stretched by means of a longitudinal stretching machine comprising a series of groups of rolls, an aqueous emulsion having a composition in which 5 to 7 wt.% of hexaxis (alcoximethyl) melamine resin and 5 to 7 wt.% of crosslinked catalytic substance are formulated relative to 100 wt.% of ionomer self-emulsifiable polyurethane resin and controlled to pH7.5 to 10.5 is coated on at least one side of the longitudinally stretched film such that the thickness of a coated material after lateral stretching becomes 0.3 to 0.1 μm. Thereafter, it is introduced into a tenter pre-heating section so as to be dried and pre-heated at a temperature of 50 to 70°C and time of 2.5+70/(T-30) to 2.5+100/(T-30) seconds, and then laterally stretched and thermally set.
NISHIMOTO SHOJI
INAGAKI MADOKA
