Lamination adhesive for sterilisation

A solvent-based two-component polyurethane adhesive composition, comprising an —OH component and an —NCO component, such that:

• the —OH component is a composition (A) comprising an amorphous prepolymer which includes two —OH end groups, the number-average molar mass Mn of which ranges from 8000 to 12,000 g/mol and which is chosen from:
• a copolyester (A1) obtained by a polycondensation reaction:
• of at least one aliphatic diol (i);
• with
• at least one aromatic diacid (ii) chosen from terephthalic acid, isophthalic acid, phthalic acid and one of their diester or anhydride derivatives;
• and
• at least one aliphatic diacid (iii) or one of its diester or anhydride derivatives;
• and
• a polyurethane (A2) obtained by a polyaddition reaction between an aliphatic diisocyanate compound (A2.P1) and an amorphous copolyester diol (A2.P2), the number-average molecular weight Mn of which ranges from 4000 to 11 500 g/mol, said copolyester being obtained by the polycondensation reaction as defined above for (A1);
• and
• the component —NCO is a composition (B) comprising a compound (B1) which includes three —NCO end groups, and which is obtained by the reaction of meta-xylylene diisocyanate (m-XDI) with a triol, said compound (B1) being:
• either the only compound comprised in (B) including three-NCO end groups;
• or else a mixture with another compound (B2) including three-NCO end groups, (B2) being an isocyanurate (B2-1) of an aliphatic diisocyanate and the content of (B1) in said mixture being at least 40% by weight, based on the total weight of said mixture.