PURPOSE: To enhance gas barrier properties and mechanical characteristics especially to oxygen and an aromatic substance by laminating a polyvinyl alcohol(PVAL) gas barrier film through homogeneous bonding by using a specific water insoluble pressure-sensitive adhesive layer.
CONSTITUTION: A gas barrier film containing PVAL high in a hydrolysis degree and cutting off water and steam is laminated to the single surface or both surfaces, perf., both surfaces of a polymer film insoluble in water and, according to circumstances, in an org. solvent through an adhesive layer having pressure- sensitive adhesion characteristics and impervious to water and steam. Herein, the gas barrier film has a thickness of 10-100 μm, an ester value of <10 mg (KOH)/g and a hydrolysis degree of >98 mol%. In both of these cases, the gas barrier film pref. comprises PVAL having a residual acetyl group content of <1 wt.% and an average DPw of >1500.
GIYUNTERU RAINHARUTO