Patent ID: 6914102

Claim:
A thermally curable hot-melt adhesive composition, comprising a polyurethane prepolymer having isocyanate groups, wherein at least 50% of the reactive isocyanate groups of the prepolymer are blocked, said prepolymer being the reaction product of (1) 20 to 40 wt % of at least one straight-chain amorphous polyester having a number average molecular mass Mn of 3000 to 6000 with (2) 40 to 60 wt % of at least one polyurethane elastomer, (3) 10 to 20 wt % of at least one polyester elastomer, (4) at least one diisocyanate, (5) at least one polyol as a chain extender, and (6) at least one blocking agent; and at least one isocyanate reactive component selected from the group consisting of polyalcohols, polyamines and hydroxy-functionalized epoxide resins; wherein the percentages are based on the total weight of polyester, polyurethane elastomer and polyester elastomer.