polyurethane-based thickener

Abstract

Thickening agents based on an aqueous preparation of non-ionic, water-dispersible or water-soluble polyurethanes, wherein these polyurethanes are producible by reacting (a) one or more hydrophilic polyols (a) containing at least two OH groups and at least two functional groups selected from the functions -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 formula (I) wherein R is a CH3-CH(CH3)-(CH2-CH(CH3))2- group or a C15H31-m group (with m = 0, 2, 4 or 6), Y is hydrogen or a methyl group and n is a number in the range of 0 to 10, and (c) one or more at least difunctional isocyanates, wherein the compounds (a), (b) and (c) are in the equivalent ratios OHa): OHb) : NCOc) of 1 : (1+x) : 2(1+y) can be implemented together, with the following conditions,that the following conditions apply: • x is a number in the range of 0.05 to 1.2, • y is a number in the range of (0.2 to 1.05) x and • equivalent ratio NCOc) > (OHa) + OHb) ) are characterized by excellent thickening effect, especially for aqueous dispersions.

Description

Field of invention

[0001] The invention relates to thickening agents based on an aqueous preparation of non-ionic, water-dispersible or soluble polyurethanes of a special structure. State of the art

[0002] Polyurethane solutions or dispersions in a water-dilutable aqueous or predominantly aqueous phase are referred to by those skilled in the art as HEUR thickeners (the acronym HEUR is derived from "nonionic"). h hydrophobically modified e ethylene oxide ur ethane block copolymer" ab) and has been used for some time in a wide variety of applications for thickening water-based dispersion paints.

[0003] The HEUR-type thickening agents, already described in US-A-4,079,028 at the end of the 1970s, are composed of linear and / or branched polyethylene glycol blocks and hydrophobic segments, which are usually linked together via urethane groups (urea groups result when amines are used instead of alcohols).

[0004] The principle underlying the thickening effect of HEUR thickeners is assumed to be that the polyethylene glycol segments ensure water compatibility and the hydrophobic segments form a viscosity-giving three-dimensional molecular composite in the dispersion paint to be thickened through an association with each other and with dispersed binder particles.

[0005] Preferred hydrophobic building blocks in commercially available HEUR thickeners are longer-chain, usually monofunctional alcohols, such as n-octanol, n-dodecanol, iso-tridecyl alcohol, iso-nonylphenol, or methyl ricinoleate. These alcohols are predominantly used as such, but also in the form of their addition products with a few equivalents of ethylene oxide. The multifunctional isocyanate building blocks predominantly used in commercially available HEUR thickeners are generally difunctional. Examples include methylenebis(4-cyclohexyl)diisocyanate, m / p-tetramethylenexylylene diisocyanate, hexamethylene diisocyanate, 2,4-toluene diisocyanate, trimethylhexamethylene diisocyanate, or 4 / 2,4'-diphenylmethane diisocyanate. The polyethylene glycol building blocks used in commercially available HEUR thickeners are usually also difunctional and have molecular weights in the range of a few thousand Daltons, for example 4500 or 10000 Daltons.

[0006] The ratios of the individual building blocks of HEUR thickeners – be they branched or unbranched polyethylene glycols, mono- or multifunctional hydrophobic alcohols, preethoxylated mono- or multifunctional hydrophobic alcohols, or di- or multifunctional short-chain alcohols used as chain extenders – are generally chosen so that each ethylene glycol segment end still reactive via a hydroxyl group is appropriately sized. a Hydrophobic alcohol is available.

[0007] The hydroxyl-terminated building blocks of HEUR thickeners are linked together by reaction with di- or multifunctional isocyanates, whereby the equivalent input ratios of the isocyanate groups and the "H-acidic" groups (usually OH groups; but NH2 groups are also possible) to be brought together for the addition reaction are chosen such that each "H-acidic" group equivalent, i.e. usually each OH group, is at least slightly less than one isocyanate group equivalent.In other words, the OH : NCO equivalent ratio is generally adjusted to a value of at least 1 : 1, ideally aiming for 1 : 1 or a predominance of OH groups compared to NCO groups by 5-10% (corresponding to an OH : NCO equivalent ratio in the range of 1.05 : 1 to 1.1 : 1) to ensure that the final product (the HEUR thickener) does not contain any free NCO groups, which are undesirable, firstly for toxicological reasons, and secondly because they can undergo undesirable subsequent reactions with formulation components when used later in formulations to be thickened. This basic principle, namely that in the production of HEUR thickeners the OH groups of the polyethylene glycol and hydrophobic alcohol building blocks slightly predominate compared to the NCO groups of the isocyanate building blocks by approximately 5-10%, is also already part of the teaching of the above-mentioned US-A-4,079,028 (compare column 3, lines 17 ff there).

[0008] WO-A-2006 / 002813 describes thickening agents based on an aqueous preparation of nonionic, water-dispersible or water-soluble polyurethanes, wherein these polyurethanes are produced by reacting (a) one or more hydrophilic polyols (a) containing at least two OH groups and at least two functional groups selected from the functions —O- (ether groups) and -COO- (ester groups), wherein the molecular weight of these hydrophilic compounds is at least 300, (b) one or more hydrophobic compounds having at least one Zerewitinoff-active hydrogen atom per molecule, wherein the molecular weight of these hydrophobic compounds is in the range of 100 to 500, and wherein each molecule of these hydrophobic compounds contains at least one linear or branched, saturated or unsaturated alkyl chain with at least five consecutive carbon atoms, which is not linked to heteroatoms.and (c) one or more at least difunctional isocyanates, wherein compounds a), b) and c) are reacted with each other in the equivalent ratios OH a) : ZH b) : NCO c) of 1 : (1+x) : 2(1+y), with the following conditions: x is a number in the range of 0.05 to 1.2 and y is a number in the range of (0.2 to 1.05) x., Description of the invention

[0009] The object of the invention was to provide polyurethane-based thickeners which, compared to prior art polyurethane thickeners, achieve a higher viscosity of the thickened product in their formulated form, while maintaining a comparatively lower inherent viscosity for the same quantity. Furthermore, the thickeners should ideally be producible without the use of volatile organic solvents. In particular, the thickeners in their formulated form should exhibit improved thickening properties in the low-shear range (low-shear range ≤ 10 s⁻¹) for the same quantity, while simultaneously maintaining low to moderate viscosity in the mid- and high-shear range. This would result in the desired technical effect of improved spreadability with reduced application force.

[0010] The present invention relates to thickening agents based on an aqueous preparation of nonionic, water-dispersible or water-soluble polyurethanes, wherein these polyurethanes can be produced by reacting (a) one or more hydrophilic polyols (a) containing at least two OH groups and at least two functional groups selected from the functions -O- (ether groups) and -COO- (ester groups), the molecular weight of these hydrophilic compounds being at least 300, (b) one or more compounds of formula (I) wherein R is a C 15 H 31-m group (with m = 0, 2, 4 or 6), Y is hydrogen or a methyl group and n is a number in the range of 0 to 10, and (c) one or more at least difunctional isocyanates, characterized in that the compounds a), b) and c) are in the equivalent ratios OH a ): OH b ) : NCO c ) of 1 : (1+x) : 2(1+y) can be implemented together, with the following conditions: x is a number in the range of 0.05 to 1.2, y is a number in the range of (0.2 to 1.05) x and equivalent ratio NCO c) > (OH a) + OH b) ).

[0011] The thickening effect of the thickening agents according to the invention is considerably better than the thickening effect of the compounds disclosed in WO-A-2006 / 002813 cited above. This applies in particular to the low-shear range (< 10 s - 1< ).

[0012] The term OH a) denotes the primary (terminal) OH groups of compounds a). The term OH b) denotes the OH groups of compounds b) that are reactive towards NCO groups. The term NCO c) denotes the isocyanate groups of compounds c).

[0013] Within the scope of the present invention, the equivalents of compounds a) are OH equivalents, of compounds b) are OH equivalents and of compounds c) are NCO equivalents.

[0014] Although the term equivalent is familiar to those skilled in the art in the field of polyurethane chemistry, for the sake of clarity it is explained below.

[0015] The term "equivalents" is to be understood in the usual sense and focuses on the available reactive groups of molecules. For example, 1 mol of a monoalcohol contains 1 mol of OH groups; 1 mol of a diol contains 2 mol of OH groups; 1 mol of a triol contains 3 mol of OH groups, and so on. Similarly, 1 mol of a diisocyanate (NCO functionality = 2) contains 2 mol of NCO groups, and 1 mol of a polyisocyanate mixture with an (average) functionality of 2.3 contains an average of 2.3 mol of NCO groups, and so on. If, for example, one wants to react alcohols and isocyanates in such a way that the compounds used are present in specific ratios with respect to their OH and NCO groups, it is advisable to use the ratios of the reactive groups instead of weight or molar ratios. This OH : NCO ratio is called the equivalent ratio.In general terms, the equivalence ratio is the numerical ratio of defined reactive groups in the reactants used.

[0016] For the sake of clarity, a practical example will further illustrate how to determine an equivalent ratio in a simple way. For example, if one sets, in accordance with the teaching of the invention... 1 mol of a polyethylene glycol (PEG, OH functionality = 2) with two OH groups per molecule with 4 mol of a hydrophobic alcohol (I) (OH functionality = 1) with one OH group per molecule and 4 mol of a diisocyanate (NCO functionality = 2) to polyurethane, then it contains the PEG used contains 2 mol OH groups, the hydrophobic alcohol (I) used contains 4 mol OH groups and the diisocyanate used contains 8 mol NCO groups.

[0017] The numerical ratio of the OH groups of the polyethylene glycol to the OH groups of the hydrophobic alcohol (I) to the NCO groups of the diisocyanate is therefore 2 : 4 : 8 or 1 : 2 : 4. Or conversely: If, for example, one wants to react the components just mentioned (PEG, hydrophobic alcohol (I) and diisocyanate) in an equivalent ratio of 1 : 3 : 3, then polyethylene glycol, hydrophobic alcohol (I) and diisocyanate must be used in a molar ratio of 0.5 : 3 : 1.5 or 1 : 6 : 3.

[0018] Preferably, x is a number in the range of 0.2 to 1.0 and particularly in the range of 0.5 to 1.0.

[0019] For the sake of clarity and unambiguity, it should be explicitly stated that y is obtained by multiplication. The expression given for y, namely "(0.2 to 1.05) x", therefore means that x—where a number from the specified range for x is to be substituted—is to be multiplied by a number from the range 0.2 to 1.05.

[0020] Preferably, y is a number in the range of (0.4 to 1.0) x and in particular in the range of (0.6 to 1.0) x.

[0021] In a preferred embodiment, x is a number in the range of 0.2 to 1.0 and y is a number in the range of (0.4 to 1.0) x.

[0022] In another preferred embodiment, x is a number in the range of 0.5 to 1.0 and y is a number in the range of (0.4 to 1.0) x. The components (a)

[0023] The hydrophilic polyols (a) contain, by definition, at least two OH groups and at least two functional groups per molecule, selected from the functions -O- (ether groups) and -COO- (ester groups), wherein the molecular weight of these hydrophilic compounds is at least 300 and preferably at least 1000. Component (a) is thus the hydrophilic molecular building block of the polyurethanes of type HEUR according to the invention. It should be expressly noted that the compounds (a) are fundamentally different from those compounds (b), which are not hydrophilic but hydrophobic.

[0024] Suitable compounds (a) include, for example, the polymerization products of ethylene oxide, their mixed or graft polymerization products, as well as polyethers obtained by condensation of polyhydric alcohols or mixtures thereof, and by ethoxylation of polyhydric alcohols, amides, polyamides, and amino alcohols. Examples of suitable compounds (a) are polyethylene glycols, addition products of ethylene oxide to trimethylolpropane, EO-PO block copolymers, and OH-terminated polyesters such as those of the type of multifunctional polycaprolactones.

[0025] Preferred compounds (a) are polyether polyols. These are hydrophilic polyols (a) that contain at least two OH groups and at least two -O- functions (ether groups) per molecule. These polyether polyols are generally so highly hydrophilic that they are water-soluble. For the production of the polyurethanes according to the invention, polyether polyols that contain at least predominantly polyethylene glycol are particularly suitable. Particularly good results are obtained when these polyethylene glycols have an average alkoxy unit content in the range of 20 to 400. Diols of the general formula HO-(CH₂-CH₂-O)x-H, where x can take on values ​​from 30 to 300, are preferred as compounds (a). These are polyethylene glycols that represent condensation products of ethylene oxide with ethylene glycol or water. Preferably, the molecular weight of these polyethylene glycols is adjusted to values ​​in the range of 2,000 to 20,000.Polyethylene glycols with a molecular weight in the range of 4,000 to 10,000 are particularly preferred as compounds (a). Regarding component (b) Component (b) consists of compounds of formula (I)

[0026] where R is a group C 15 H 31-m (with m = 0, 2, 4 or 6), Y is hydrogen or a methyl group and n is a number in the range of 0 to 10.

[0027] The compounds (I) contain a structural element -(CH₂-CHY-O)ₙ-. It should be noted that the formula notation used is intended to express that this structural element is derived from ethylene oxide (EO) or propylene oxide (PO), namely insofar as—logically, if the index n is not zero—this structural element results synthetically from an addition of EO or PO, or ethylene glycol or propylene glycol (for n = 1), or from a polyaddition of EO and / or PO, or polyethylene glycol or polypropylene glycol, or corresponding mixed EO-PO copolymers (for n ≥ 2). It should further be expressly stated that this structural element can be composed exclusively of EO units, exclusively of PO units, or can contain EO and PO units in mixed form, either in blocks or in a statistically distributed manner.Therefore, the formulaic representation used for the aforementioned structural element is an abbreviated notation for the possibilities mentioned, which are self-evident to the knowledgeable professional.

[0028] For example, Y = H and n = 5 means that the corresponding structural element contains five linked EO units, which corresponds to a grouping -(O-CH 2 -CH 2 -) 5 -; whereas Y = CH 3 and n = 5 means that the structural element contains five linked PO units, which corresponds to a grouping -(O-CH 2 -CH(CH 3 )) 5 -, where - as is known to those skilled in the art - the orientation of the methyl group within the structural element can be realized in two ways for each PO building block, namely as - (O-CH 2 -CH(CH 3 ))- or -(O-CH(CH 3 )-CH 2 )-.

[0029] In one embodiment, such compounds (I) are used, wherein R is a group C 15 H 31-m (with m = 0, 2, 4 or 6), Y is hydrogen or a methyl group and n is the number 0; these compounds (I) are cardanols.

[0030] In one embodiment, such compounds (I) are used, wherein R is a group C 15 H 31-m (with m = 0, 2, 4 or 6), Y is hydrogen or a methyl group and n is a number in the range of 1 to 10; these compounds (I) are cardanol alkoxylates.

[0031] The compounds (I) can be used individually or as a mixture. The components (c)

[0032] All multifunctional aromatic, alicyclic, and aliphatic isocyanates are suitable as at least difunctional isocyanates (c). Preferably, the suitable multifunctional isocyanates contain on average 2 to at most 4 NCO groups. Diisocyanates are preferred as compounds (c).

[0033] For example, suitable isocyanates include 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), hydrogenated MDI (H12 MDI), xylylene diisocyanate (XDI), tetramethylxylene diisocyanate (TMXDI), 4,4'-diphenyldimethylmethane diisocyanate, di- and tetraalkyldiphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, the isomers of toluene diisocyanate (TDI), optionally in mixture, 1-methyl-2,4-diisocyanato-cyclohexane, 1,6-diisocyanato-2,2,4-trimethylhexane, 1,6-diisocyanato-2,4,4-trimethylhexane, 1-isocyanatomethyl-3-isocyanato-1,5,5-trimethylcyclohexane, chlorinated and brominated Diisocyanates, phosphorus-containing diisocyanates, 4,4'-diisocyanatophenylperfluoroethane, tetramethoxybutane-1,4-diisocyanate, butane-1,4-diisocyanate, hexane-1,6-diisocyanate (HDI), dicyclohexylmethane diisocyanate, cyclohexane-1,4-diisocyanate, ethylene diisocyanate, phthalic acid bisisocyanatoethyl ester, and polyisocyanates with reactive halogen atoms.such as 1-chloromethylphenyl-2,4-diisocyanate, 1-bromomethylphenyl-2,6-diisocyanate, and 3,3-bischloromethyl ether-4,4'-diphenyl diisocyanate. Sulfur-containing polyisocyanates are obtained, for example, by reacting 2 mol of hexamethylene diisocyanate with 1 mol of thiodiglycol or dihydroxydihexyl sulfide. Other important diisocyanates are trimethylhexamethylene diisocyanate, 1,4-diisocyanatobutane, 1,2-diisocyanatododecane, and dimer fatty acid diisocyanate. Partially disguised polyisocyanates, which enable the formation of self-crosslinking polyurethanes, e.g., dimeric toluene diisocyanate, or polyisocyanates partially reacted with, for example, phenols, tertiary butanol, phthalimide, or caprolactam, are of particular interest. According to the invention, it is preferablythat the isocyanates (c) used to produce the polyurethanes contain at least predominantly isophorone diisocyanate (IPDI) and / or tetramethylxylene diisocyanate (TMXDI). Preferably, component (c) is selected exclusively from the group consisting of isophorone diisocyanate (IPDI) and tetramethylxylene diisocyanate (TMXDI).

[0034] In a preferred embodiment, isocyanates with a functionality of 2 (difunctional isocyanates) are used.

[0035] In another embodiment, isocyanates with a functionality above 2 are used — partially or entirely — when it is desired to produce polyurethanes with a branched structure. The polyurethanes to be used according to the invention

[0036] The OH / OH / NCO ratio of the polyurethanes to be used according to the invention, which must necessarily contain the building blocks (a), (b) and (c), can in principle be varied over a wide range, provided that the conditions set out above are observed. Thickener concentrates

[0037] Another subject of the invention is thickener concentrates containing (A) Water, (B) Non-ionic, water-dispersible or water-soluble polyurethanes obtainable by reacting (a) one or more hydrophilic polyols (a) containing per molecule at least two OH groups and at least two functional groups selected from the functions -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 formula (I) wherein R is a C15H31-m group (with m = 0, 2, 4 or 6), Y is hydrogen or a methyl group and n is a number in the range of 0 to 10, and (c) one or more, at least difunctional, isocyanates, wherein compounds a), b) and c) are reacted with each other in the equivalent ratios OH a) : OH b) : NCO c) of 1 : (1+x) : 2(1+y), with the following conditions: x is a number in the range of 0.05 to 1.2, y is a number in the range of (0.2 to 1.05)x and equivalent ratio NCO c) > (OH a) + OH b) ), and (C) optionally one or more organic solvents and / or nonionic surfactants of the type of addition compounds of ethylene and / or propylene oxide to alcohols with 8-18 Carbon atoms.

[0038] Regarding preferred embodiments with respect to compounds (B), the above applies. The solvents (C) are volatile organic solvents. Examples include low-molecular-weight alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, ethanediol, propanediol, butanediol, glycerol, and trimethylolpropane. Nonionic surfactants of the type of admixtures of ethylene and / or propylene oxide to alcohols with 8-18 carbon atoms (C) are preferred, particularly those with 2 to 4 moles of ethylene oxide per mole of alcohol. The carbon skeleton of the alcohols can be saturated or unsaturated, linear or branched. As an example of a suitable compound (C) of this class, Dehydol 04 (commercial product of Cognis) may be mentioned, an adsorption product of 4 mol ethylene oxide per mol octanol.

[0039] Furthermore, the invention relates to the use of the thickening agents or thickener concentrates according to the invention for thickening aqueous systems, preferably aqueous dispersions, selected from the group consisting of aqueous automotive and industrial paints, printing and textile inks, pigment printing pastes, aqueous pharmaceutical formulations, cosmetic formulations or pharmaceutical-cosmetic formulations, plant protection formulations, filler and pigment dispersions, preparations of detergents, adhesives, waxes and polishes, as well as for petroleum production, in particular for thickening aqueous plaster and paint in dispersion form. Examples Chemicals used and abbreviations used

[0040] PEG 8000: Pluriol E 8000 (BASF) IPDI: Isophorone diisocyanate (IPDI, Degussa / Hüls) Exxal 9: Isononanol (oxomethylated propentrimer; trade product "Exxal 9" from Exxon Mobil Chemical) Dehydol 04 Addition product of 4 mol ethylene oxide to 1 mol n-octanol (Cognis) NeoCryl XK 98 Acrylic emulsion (DSM NeoResins) Cardanoyl*8EO Addition product of 8 mol ethylene oxide to 1 mol cardanol demineralized water demineralized water Polyurethane production Example 1 (according to the invention)

[0041] 198 g (24 mmol) of PEG 8000 (BASF polyethylene glycol) were placed in a 1 L four-necked flask. The flask was evacuated twice and aerated with nitrogen. A vacuum was then applied, and the mixture was heated to 100°C. At this temperature, the mixture was dehydrated for two hours under a vacuum of at least 10 mbar. The flask was then aerated with nitrogen, and the protective atmosphere was maintained by a gentle nitrogen stream. The mixture was stirred at 120 rpm throughout the entire reaction. Subsequently, 40.9 g of Cardanol*8 EO (72 mmol) and 16.0 g of isophorone diisocyanate (72 mmol) were added successively. The reaction temperature was maintained at 110°C during the addition and throughout the subsequent reaction. Once no residual isocyanate was detectable, the temperature was maintained at 110°C, and 154.0 g of Dehydrogen O4 was added. This mixture was stirred until homogeneous.Subsequently, 364.2 g of deionized water were added while stirring. After the product had cooled, approximately 740 g of a viscous, cloudy, slightly yellowish polymer solution were isolated from the reaction vessel. The dry residue (for the determination of which approximately 2 g of the polymer solution prepared as described were dried in a 10 cm aluminum dish at 105°C for 1.5 h in a forced-air drying oven) was 51.1 wt% and the Brookfield viscosity was 8.9 Pa·s (Brookfield RVT viscometer / spindle 3 / 10 rpm / 23°C). The lacquer viscosity in the Epprecht viscometer was 140 Pa·s (spindle C). Example 2 (for comparison)

[0042] 185.7 g (24 mmol) of PEG 8000 (BASF polyethylene glycol) were placed in a 1 L four-necked flask. The flask was evacuated twice and aerated with nitrogen. A vacuum was then applied, and the mixture was heated to 100°C. At this temperature, the mixture was dehydrated for two hours under a vacuum of at least 10 mbar. The flask was then aerated with nitrogen, and the protective atmosphere was maintained by a gentle nitrogen stream. The mixture was stirred at 120 rpm throughout the entire reaction. Subsequently, 10.6 g (72 mmol) of Exxal 9 (isononanol) and 16.0 g (72 mmol) of isophorone diisocyanate were added successively. The reaction temperature was maintained at 110°C during the addition and throughout the subsequent reaction. Once no residual isocyanate was detectable, the temperature was maintained at 110°C and 123.3 g of Dehydrogen O4 was added. This mixture was stirred until homogeneous.Subsequently, 296.2 g of deionized water were added while stirring. After the product had cooled, approximately 622.3 g of a viscous, cloudy, slightly yellowish polymer solution were isolated from the reaction vessel. The dry residue (for the determination of which approximately 2 g of the polymer solution prepared as described were dried in a 10 cm aluminum dish at 105°C for 1.5 h in a forced-air drying oven) was 50.4 wt%, and the Brookfield viscosity was 4.85 Pa·s (Brookfield RVT viscometer / spindle 3 / 10 rpm / 23°C). The lacquer viscosity in the Epprecht viscometer was 190 Pa·s (spindle C). Determination of dispersion thickening

[0043] 0.2% of the respective polymeric active ingredient according to the examples above (based on and calculated for the active substance without Dehydol O4) was homogenized with 0.41 g of a mixture of 31.4 wt% propanediol and 68.6 wt% water. Then, 20 g of the aqueous polyacrylate dispersion Neocryl XK 90 (45% solids content; Neo Resins) was added, and the mixture was stirred homogeneously with a wooden spatula for approximately two minutes. After a standing time of at least 20 hours, the mixture was stirred carefully again with a wooden spatula. The viscosity was then measured using a Brookfield Haake RC20-CPS-P cone-plate viscometer with a C50-1 cone. The results can be found in Table 1. Table 1: Dispersion Viscosities D [1 / s] Example 1 (Invention) Example 2 (Comparison) 0,1 321,8 - 0,5 237,0 - 1,0 186,0 2,1 2,0 142,6 2,6 5,0 78,6 2,7 10,0 48,1 2,6 50,0 11,6 1,9 100,0 5,2 1,6 300,0 1,5 1,1 500,0 0,7 0,9 4800,0 0,1 -

[0044] The entry "-" in the "Example 2" column of Table 1 indicates that no measurement was possible. The dispersion viscosities in Table 1 are given in [mPas]. The abbreviation "D" in the first column of Table 1 stands for shear rate.

[0045] Conclusion: Table 1 clearly shows that the thickeners according to the invention (Example 1) achieve a significantly improved thickening efficiency in the low-shear range than a thickener according to the prior art (Example 2).

Claims

1. 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 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 C15H31-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, characterized in that the compounds a), b) and c) are reacted with one another in the equivalent ratios OHa):OHb):NCOc) 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 NCOc) > (OHa) + OHb)).

2. Thickeners according to Claim 1, where component (a) is selected from the group of polyethylene glycols with a molecular weight in the range from 2000 to 20 000.

3. Thickeners according to Claim 1 or 2, where component (b) is selected from the group of compounds (I), in which R is a C15H31-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.

4. Thickeners according to any of Claims 1 to 3, where component (c) is selected from the group isophorone diisocyanate and tetramethylxylene diisocyanate.

5. Thickener concentrates comprising (A) water (B) nonionic water-dispersible or water-soluble polyurethanes according to any of Claims 1 to 4, and (C) 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.

6. Use of the thickeners according to Claims 1 to 4 for thickening emulsion paints.

7. Use of the thickeners according to Claims 1 to 4 for thickening aqueous dispersions.

8. Use according to Claim 7, where the aqueous dispersions are cosmetic preparations.