| 摘要 |
The aqueous-based cross-linkable binder composition comprising(A) an aqueous dispersion of an aldehyde-functional polyurethane having a number average molecular weight of more than 1,000 and an average aldehyde functionality of >=2, which polyurethane comprises ionic and/or non-ionic dispersing groups, and(B) a low-molecular weight aldehyde-reactive cross-linker selected from the group of low-molecular weight polyamines and low-molecular weight compounds comprising at least one group of one of the formulae E<1>-CHR<1>-E<2 >and H-C-(E<1>E<2>E<3>), wherein -E<1>, -E<2 >and -E<3 >are independently chosen from electron-withdrawing groups such as -P(=O)-O-, -CO-, -CN, -SO2-, -NO2 and wherein R<1 >has the meaning of hydrogen or a hydrocarbon radical having 1 to 10 carbon atoms.Preference is given to a coating composition wherein the ionic dispersing group is an anionic dispersing group selected from the group of carboxylate, sulphonate and/or phosph(on)ate salt groups, and/or wherein for the nonionic dispersing group use is made of a C1-C4 alkoxy poly C2-C3 alkylene-oxide group in an amount between 2.5 and 20 wt. %, based on the polyurethane.
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