Hybrid solvent-borne polyurethane adhesives

Abstract

An adhesive composition includes a polyurethane polymer, a solvent and a co-solvent. The polyurethane polymer is an internally and/or externally hydrophilized thermoplastic polyurethane having a mass average molecular weight Mw, as determined by gel permeation chromatography against polystyrene standards using N,N-dimethyl acetamide as the eluent, of ≥50000 g/mol, the solvent is a polar-aprotic solvent such as MEK and the co-solvent is water. The polyurethane polymer, the solvent and the co-solvent are present in such amounts that they form a dispersion. The polyurethane polymer content is ≥10 weight-%, based on the total weight of the composition and the weight ratio of solvent to co-solvent is in a range of ≥1:1 to ≤4:1.

Dependencies are inferred from the claim text.