Thickeners based on polyurethane
Thickeners, which are based on an aqueous preparation of nonionic water-dispersible or water-soluble polyurethanes, it being possible to produce these polyurethanes by reacting (a) one or more hydrophilic polyols (a) which contain, per molecule, at least two OH groups and at least two functional groups which are selected from the functions —O— (ether groups) and —COO— (ester groups), where the molecular weight of these hydrophilic compounds is at least 300, (b) one or more compounds of the formula (I), in which R is a CH 3 —CH(CH 3 )— (CH 2 —CH(CH 3 )) 2 — group or a C 15 H 31-m group (where m=0, 2, 4 or 6), Y is hydrogen or a methyl group and n is a number in the range from 0 to 10, and (c) one or more at least difunctional isocyanates, in which the compounds a), b) and c) are reacted with one another in the equivalent ratios OH a) :OH b) :NCO c) of 1:(1+x):2(1+y), with the provisos that the following conditions apply: x is a number in the range from 0.05 to 1.2, y is a number in the range from (0.2 to 1.05)x, and equivalent ratio NCO c) >(OH a) +OH b) ) are characterized by excellent thickening effect, in particular for aqueous dispersions.
1. A thickener comprising an aqueous preparation of a nonionic water-dispersible or water-soluble polyurethane, prepared by the process comprising the step of reacting a mixture comprising:
(a) one or more hydrophilic polyols which contain, per molecule, at least two OH groups and at least two functional groups selected from the group consisting of —O— (ether groups) and —COO— (ester groups), wherein the molecular weight of these hydrophilic compounds is at least 300,
(b) one or more compounds of the formula (I)
wherein R is a C 15 H 31 , group, and wherein m has a value of 0, 2, 4 or 6, Y is hydrogen or a methyl group and n is a number in the range from 0 to 10, and
(c) one or more difunctional isocyanates,
wherein the compounds (a), (b) and (c) are reacted with one another in the equivalent ratios OH (a) :OH (b) :NCO (c) of 1:(1+x):2(1+y), and wherein:
x is a number in the range from 0.05 to 1.2,
y is a number in the range from (0.2 to 1.05) x , and
equivalent ratio NCO (c) >(OH a) +OH b) ).
2. The thickener of claim 1 , wherein component (a) is selected from the group consisting of polyethylene glycols with a molecular weight having a range of about 2000 to about 20 000.
3. The thickener of claim 1 , wherein component (c) is selected from the group consisting of isophorone diisocyanate and tetramethylxylene diisocyanate.
4. A thickener concentrate comprising:
water,
a nonionic water-dispersible or water-soluble polyurethane of claim 1 , and
optionally, one or more organic solvents and/or nonionic surfactants of the type of addition compounds of ethylene oxide and/or propylene oxide onto alcohols having 8 to 18 carbon atoms.
5. A method of thickening emulsion paints, the method comprising incorporating the thickener of claim 1 into a paint emulsion.
6. A method of thickening aqueous dispersions, the method comprising incorporating the thickener of claim 1 into an aqueous dispersion.
7. The method of claim 6 , wherein the aqueous dispersion is a cosmetic preparation.
8. The thickener concentrate of claim 4 further comprising one or more organic solvents and/or nonionic surfactants of the type of addition compounds of ethylene oxide and/or propylene oxide onto alcohols having 8 to 18 carbon atoms.