Abstract: The solvent-free two-component adhesive composition of the present invention comprises a polyol component (A) and a polyisocyanate component (B), and the viscosity of the mixture at 80° C. immediately after the point of time the components (A) and (B) are mixed together is 900 mPa·s or higher. The component (A) may be a polyol having a number average molecular weight of 800 or larger, or a mixture thereof, and the viscosity of the component (B) at 25° C. may be 20,000 mPa·s or higher. The composition may be used for laminating metal foil of 5 to 15 m thickness with a plastic film. By using the composition of the present invention, the occurrence of blocking due to the seepage of the adhesive from metal foil is prevented. The present invention includes a process of lamination using the same.