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Abstract

The hot-melt adhesive of the invention includes A) at least one polyurethane prepolymer of a) at least one polyisocyanate, in particular, toluene diisocyanate and/or MDI, b) at least one polyalkylene glycol at a concentration of more than 10% by weight based on total hot-melt adhesive, in particular, polypropylene glycol, c) at least one polyester glycol, preferably of at least two polyester glycols having different glass transition temperature, and B) optional additives such as d) a resin, particularly a hydrocarbon resin, and e) a stabilizer, particularly toluenesulfonyl isocyanate. Preferably, the hot-melt adhesive has a melt viscosity ranging from 10 to 300 Pa.s at 130.degree. C. The PU pre-polymer has only one single Tg in the DSC diagram. The hot-melt adhesive is notable for its high creep resistance with similarly high initial and final strength. Thus, it is predominantly used in the shoe industry, particularly in coating machines integrable in the shoe production line not including a pre-crosslinking stage using steam or a drying channel. Preferably, the hot-melt adhesive is produced using the single step process.

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First Claim