Patent ID: 8063138

Claim:
A process for preparing polyester-polyurethane dispersions comprising: A) reacting i) one or more polyol components having a number average molecular weight of at least 300 daltons, at least 60% by weight of component i) being a polyester polyol with the fraction of aromatic carboxylic acid groups relative to all of the carboxylic acid groups used to prepare said polyester polyol being at least 60 mol %, ii) optionally one or more polyol components having a number average molecular weight of 62 to 299 daltons, and iii) optionally a compound which is monofunctional for the purposes of the isocyanate polyaddition reaction and has an ethylene oxide content of at least 50% by weight and a number average molecular weight of at least 400 daltons, with iv) a polyisocyanate to form a prepolymer, B) dissolving the prepolymer in an organic solvent, C) reacting the prepolymer with v) one or more aliphatic and/or alicyclic primary and/or secondary polyamines having a number average molecular weight of 60 to 300 daltons, said polyamine optionally being in combination with hydrazine or hydrazine hydrate, and vi) a hydrophilicized aliphatic diamine, D) precipitating the product from C) by adding water to form a dispersion, and E) removing the organic solvent.