| 摘要 |
The invention relates to a thickening agent based on an aqueous preparation of water-dispersible or water-soluble non-ionic polyurethanes. Said polyurethanes can be produced by reacting (a) at least one hydrophilic polyol (a) containing, per molecule, at least two OH groups and at least two functional groups that are selected from the functions -O- (ether groups) and -COO- (ester groups), the molar weight of said hydrophilic compounds amounting to at least 300, (b) at least one hydrophobic compound containing, per molecule, at least one zerewitinoff-active hydrogen atom, and at least one linear or branched, saturated or unsaturated alkyl chain which comprises at least five successive C atoms and is not linked to heteroatoms, the molar weight of said hydrophobic compounds being between 100 and 500, and (c) at least one at least difunctional isocyanate, said polyurethanes being characterised in that the compounds a), b) and c) are reacted in the atomic ratios OH<SUB>a</SUB>): ZH<SUB>b</SUB>): NCO<SUB>c</SUB>) of 1: (1 +x): 2(1 +y), on the proviso that the following conditions hold good: x represents a number between 0.05 and 1.2, and y represents a number between (0,2 and 1,05) x. The inventive thickening agent is characterised by an excellent thickening action, especially for aqueous dispersions. |
