| abstract |
Described are thickening agents based on an aqueous preparation of non-ionic water-dispersible or water-soluble polyurethanes. The thickening agents may be prepared by reacting: a) polyfunctional isocyanates with: b) polyether polyols, c) monohydric alcohols with at least one other polar group, in particular an ester, amide and/or oxazoline group, and d) optionally polyhydric alcohols. Such thickening agents are particularly suitable for use in the manufacture of disperse dyes. They have a relatively low intrinsic viscosity, are highly effective and exhibit close to newtonian flow properties. They can be prepared without using solvents. |