| abstract |
A polyurethane (polymer hybrid) dispersion with reduced hydrophilicity is described, which has been prepared by reacting n a) 50 to 100 parts by weight of a hydrophobically modified block copolymer (A)(i) having two or more hydroxyl groups and a molecular weight of 500 to 6 000 dalton and/or n 50 to 100 parts by weight of a hydrophobic block copolymer (A)(ii) having two or more hydroxyl groups and a molecular weight of 500 to 6 000 dalton and/or n 50 to 100 parts by weight of a hydrophobically modified random copolymer (A)(iii) having two or more hydroxyl groups and a molecular weight of 500 to 6 000 dalton, n b) 14 to 140 parts by weight of a polyol component (B), n c) 25 to 250 parts by weight of a polyisocyanate component (C), n d) 2 to 20 parts by weight of a neutralizing component (D), n e) 3 to 30 parts by weight of a chain-extender component (E) and n f) 100 to 5 000 parts by weight of water n to give a solvent-free or low-solvent polyurethane dispersion and, if required, then allowing said dispersion to react further with n g) 117.5 to 3 200 parts by weight of a monomer component (F) and n h) 0.5 to 50 parts by weight of an initiator component (G) n to give a solvent-free or low-solvent polyurethane polymer hybrid dispersion. n By using hydrophobically modified block copolymers and/or hydrophobically modified random copolymers as polyols, it is possible to obtain polyurethane (polymer hybrid) dispersions with reduced hydrophilicity or water absorption, which moreover can be prepared in solvent-free or low-solvent form with high solids contents. |