| abstract |
The present invention provides a process for preparing aqueous polyurethane-polyurea dispersions which comprises (A) first an NCO-containing polyurethane prepolymer being produced by reaction of (A1) polyisocyanates with (A2) polymeric polyols and/or polyamines having number average molecular weights of more than 400 to 8000 g/mol, (A3) optionally low molecular weight compounds having number average molecular weights of 17-400 g/mol selected from the group consisting of mono- and polyalcohols, mono- and polyamines and amino alcohols, (A4) isocyanate-reactive ionically or potentially ionically hydrophilizing compounds and/or isocyanate-reactive nonionically hydrophilizing compounds, (A5) isocyanate-reactive compounds comprising at least one C7- to C24-alkyl or C7- to C24-alkenyl group, and (A6) isocyanate-reactive compounds comprising at least one polysiloxane group, and (B) the still free NCO groups of the prepolymer being reacted with isocyanate-reactive monoamines, polyamines, hydrazine and/or hydrazides sufficient for an arithmetic ratio of the isocyanate-reactive NH groups to the NCO groups in the range from 0.7 to 1.2.) |