Patent ID: 6908981

Claim:
A laminate adhesive, consisting essentially of a polyisocyanate component and a polyol component consisting essentially of polyester polyol, wherein the polyester polyol consists essentially of an acid component and a polyhydric alcohol component, the acid component consisting of naphthalenedicarboxylic acid, and optionally a dimer acid and/or phthalic acid; wherein the laminate adhesive satisfies the following requirement: when a composite film is produced by coating opposed first and second surfaces of an aluminum foil having a thickness of 9 μm with the laminate adhesive in an amount of 2.5 g/m 2 by weight of a solid content of the adhesive per unit area by use of a dry laminator or a solvent-free laminator, by adhering a polyethylene terephthalate film having a thickness of 12 μm to the first surface of the aluminum foil and an unextended polypropylene film having a thickness of 70 μm to the second surface, and by curing the adhered films at 50° C. for 3 days, to produce the composite film; and when cyclic ester compounds eluted from the laminate adhesive are measured by forming a bag from the composite film, filling the bag with ion-exchange distilled water in an amount of 0.5 mL/cm 2 per unit area of the interior surface of the bag, sterilizing the bag by heated water under a pressure of 19.6×10 4 Pa at 120° C. for 30 minutes, extracting the water contained in the bag in a solid phase modified with an octadecyl group, drawing a sample from the extract, dissolving the sample in methanol in an amount of one hundredth of the original amount of water contained in the bag, and measuring the presence of cyclic ester compounds in the sample by gas chromatography-flame ionization, wherein the cyclic ester compounds are present at a concentration of 0.5 ppb or less per 0.5 mL/cm 2 of the composite film, as determined by gas chromatograph-flame ionization using dibutyl phthalate as a reference compound.