Adhesive composition, the preparation method and use thereof

An adhesive composition comprising an aqueous anionic polyurethane dispersion and a uretdione group-containing polyisocyanate, wherein the aqueous polyurethane dispersion comprises a polyurethane polymer and water, and wherein the polyurethane polymer is obtained by the reaction of a system comprising the following components:

• a) a polyisocyanate;
• b) an isocyanate reactive group-containing compound including a polyester polyol, wherein the polyester polyol is in an amount of greater than 10% by weight, relative to the total weight of the isocyanate reactive group-containing compound;
• and
• c) a chelating agent in an amount of 0.01% to 1.95% by weight, relative to the total weight of solid constituents of the composition;
• wherein the uretdione group content of the polyisocyanate is 0.8% by weight to 20% by weight, relative to the total weight of solid constituents of the aqueous polyurethane dispersion and the polyisocyanate;
• the enthalpy of fusion of the polyurethane polymer is greater than 15 J/g, or the enthalpy of fusion of the composition is greater than 15 J/g after film forming by drying, which is measured by DSC from the first heating curve from 20° C. to 100° C. according to DIN 65467.