EP2828311A1 - Radiation-curable aqueous dispersions - Google Patents

Abstract

The invention relates to radiation-curable aqueous dispersions with mercapto groups, processes for their preparation, and their use.

Description

 Radiation-curable aqueous dispersions

The invention relates to radiation-curable aqueous dispersions with mercapto groups, to processes for their preparation, to their use.

From US Pat. No. 6,551,710 B1 it is known to allow radiation-curable acrylates to react with compounds containing thio groups.

A disadvantage of these systems is that the coating compositions are applied from solvents and thus have a high VOC value, and that the mixtures of UV-curable compound and di- and polythiol component are mixed together for immediate reaction and thus have no shelf life.

Reactive mixtures of acrylates and thiol compounds are also known

EP 1275668. Again, the mixtures are scheduled for immediate reaction, storage and ability is not provided. A. K. O'Brian, N.B. Cramer, C.N. Bowman, in "Oxygen Inhibition in Thiol-Acrylate Photopolymerizations", J. Polym. Sci., Part A: Polymer Chemistry 44: 2007-2014 (2006) describe the influence of the presence of oxygen (O2) on the copolymerization of acrylates with thiols in Higher functional thiols lead to a faster polymerization at the same concentration of thiol functionalities, which makes their stabilization even more difficult.

In order to reduce a reaction between thiol compounds and double bond-containing systems, it is necessary according to the teaching of US Pat. No. 5,459,173 to stabilize these.

The object of the present invention was to provide water-dispersible radiation-curable compounds which are curable by radiation and by reaction with mercapto groups. The dispersions should be stable on storage and be prepared from simple Aubaukomponenten and the coatings obtained with these should have a high hardness.

The problem has been solved by containing aqueous dispersions

at least one water-dispersible radiation-curable polyurethane (A) containing as structural components

 (Aa) at least one organic aliphatic, aromatic or cycloaliphatic di- or polyisocyanate,

 (Ab) at least one compound (Ab) having at least one isocyanate-reactive group and at least one free-radically polymerizable unsaturated group,

(Ac) optionally at least one compound having at least two isocyanate-reactive groups,

(Ae) optionally at least one compound with exactly one isocyanate-reactive group, (Ag) at least one compound having at least one isocyanate-reactive group and at least one dispersive-active group,

 such as

at least one water-dispersible compound (B) having at least two mercapto groups.

Water-dispersible, radiation-curable polyurethanes (A)

The reaction mixtures obtained in the preparation of the polyurethanes of the invention generally have a number average molecular weight M _n of less than 10,000 g / mol, preferably less than 5000 g / mol, more preferably less than 4000 and most preferably less than 2000 g / mol (determined by gel permeation chromatography with tetrahydrofuran and polystyrene as standard). The component (Aa) may be monomers or oligomers of aliphatic or cycloaliphatic diisocyanates.

The NCO functionality of such compounds is generally at least 1.8, and may be up to 8, preferably from 1.8 to 5 and more preferably from 2 to 4.

The content of isocyanate groups, calculated as NCO = 42 g / mol, is usually from 5 to 25% by weight.

The diisocyanates are preferably isocyanates having 4 to 20 C atoms. Examples of customary diisocyanates are aliphatic diisocyanates such as tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, hexamethylene diisocyanate (1,6-diisocyanatohexane), octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, derivatives of lysine diisocyanate, trimethylhexane diisocyanate or tetramethylhexane diisocyanate, cycloaliphatic Diisocyanates such as 1,4,4,1,3 or 1,2-diisocyanatocyclohexane, 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane, 1-isocyanato-3,3,5-trimethyl-5- ( isocyanatomethyl) cyclohexane (isophorone diisocyanate), 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane or 2,4- or 2,6-diisocyanato-1-methylcyclohexane and also 3 (or 4), 8 (or 4) 9) -bis (isocyanato-methyl) -tricyclo [5.2.1.0 ^{2 6} ] decane isomer mixtures. There may also be mixtures of said diisocyanates.

Particularly preferred are hexamethylene diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate and 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane, very particularly preferred are isophorone diisocyanate and hexamethylene diisocyanate, particularly preferably hexamethylene diisocyanate. Isophorone diisocyanate is usually present as a mixture, namely of the cis and trans isomers, generally in the ratio of about 60:40 to 80:20 (w / w), preferably in the ratio of about 70:30 to 75 : 25 and most preferably in the ratio of about 75:25. Dicyclohexylmethane-4,4'-diisocyanate may also be present as a mixture of the different cis and trans isomers.

Cycloaliphatic isocyanates are those which contain at least one cycloaliphatic ring system.

Aliphatic isocyanates are those which contain exclusively straight or branched chains, ie aeyclic compounds.

There are also higher isocyanates with an average of more than 2 isocyanate groups into consideration. For example, triisocyanates such as triisocyanatononane or 2,4,6-triisocyanate-anatotoluene are suitable for this purpose.

Suitable polyisocyanates are polyisocyanates having isocyanurate groups, uretdione diisocyanates, biisocyanate-containing polyisocyanates, polyisocyanates containing urethane or allophanate groups, polyisocyanates containing oxadiazinetrione groups, uretonimine-modified polyisocyanates, carbodiimide, hyperbranched polyisocyanates, polyurethane-polyisocyanate prepolymers or polyurea-polyisocyanate prepolymers of straight-chain or branched C 4 -C 20 -alkylene diisocyanates, cycloaliphatic diisocyanates having a total of 6 to 20 carbon atoms or mixtures thereof.

The usable di- and polyisocyanates preferably have a content of isocyanate groups (calculated as NCO, molecular weight = 42) of 10 to 60% by weight, based on the diisocyanate and polyisocyanate (mixture), preferably 15 to 60% by weight and particularly preferably 20 to 55 wt%. Preference is given to aliphatic or cycloaliphatic, in the context of this document as (cyclo) aliphatic, di- and polyisocyanates, e.g. the abovementioned aliphatic or cycloaliphatic diisocyanates, or mixtures thereof.

For the present invention, both di- and polyisocyanates can be used, which are obtained by phosgenation of the corresponding amines, as well as those which are prepared without the use of phosgene, ie by phosgene-free process. For example, EP-A-0 126 299 (USP 4 596 678), EP-A-126 300 (USP 4 596 679) and EP-A-355 443 (USP 5 087 739) disclose (cyclo) aliphatic diisocyanates, for example, such as 1,6-hexamethylene diisocyanate (HDI), isomeric aliphatic diisocyanates having 6 carbon atoms in the alkylene radical, 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane and 1-isocyanato-3-isocyanato-methyl -3,5,5-trimethylcyclohexane (isophorone diisocyanate or IPDI) are prepared by reacting the (cyclo) aliphatic diamines with, for example, urea and alcohols to give (cyclo) aliphatic biscarbamic acid esters and their thermal decomposition into the corresponding diisocyanates and alcohols. The synthesis is usually carried out continuously in a cyclic process and optionally in the presence of N-unsubstituted carbamic acid esters, dialkyl carbonates and other by-products recycled from the reaction process. Di- or polyisocyanates obtained in this way generally have a very low or even non-measurable proportion of chlorinated compounds, which leads to favorable color numbers of the products.

In one embodiment of the present invention, the di- and polyisocyanates (Aa) have a total hydrolyzable chlorine content of less than 200 ppm, preferably less than 120 ppm, more preferably less than 80 ppm, most preferably less than 50 ppm, especially less than 15 ppm and especially less than 10 ppm. This can be measured, for example, by ASTM D4663-98. Of course, it is also possible to use diisocyanates and polyisocyanates (Aa) with a higher chlorine content.

The di- and polyisocyanates (Aa) may also be present at least partially in blocked form. Also preferred are 1) isocyanurate-containing polyisocyanates of aliphatic and / or cycloaliphatic diisocyanates. Particular preference is given here to the corresponding aliphatic and / or cycloaliphatic isocyanatoisocyanurates and in particular those based on hexamethylene diisocyanate and isophorone diisocyanate. The isocyanurates present are, in particular, tris-isocyanatoalkyl- or tris-isocyanatocycloalkyl isocyanurates, which are cyclic trimers of the diisocyanates, or mixtures with their higher homologs having more than one isocyanurate ring. The isocyanato-isocyanurates generally have an NCO content of 10 to 30 wt .-%, in particular 15 to 25 wt .-% and an average NCO functionality of 2.6 to 8.

2) uretdione diisocyanates having aliphatically and / or cycloaliphatically bonded isocyanate groups, preferably aliphatically and / or cycloaliphatically bonded and in particular those derived from hexamethylene diisocyanate or isophorone diisocyanate. Uretdione diisocyanates are cyclic dimerization products of diisocyanates.

 The uretdione diisocyanates can be used as the sole component or in a mixture with other polyisocyanates, in particular those mentioned under 1).

3) biuret-containing polyisocyanates having cycloaliphatically or aliphatically bound, preferably cycloaliphatically or aliphatically bound isocyanate groups, in particular tris (6-isocyanatohexyl) biuret or mixtures thereof with its higher homologs. These biuret polyisocyanates generally have an NCO content of 18 to 22 wt .-% and an average NCO functionality of 2.8 to 4.5 on. ) Containing urethane and / or allophanate polyisocyanates having aliphatically or cycloaliphatically bonded, preferably aliphatically or cycloaliphatically bonded isocyanate groups, as for example by reacting excess amounts of hexamethylene diisocyanate or isophorone diisocyanate with monohydric or polyhydric alcohols such as methanol, ethanol, / Propanol, n-propanol, n-butanol, / so-butanol, se / butanol, feri-butanol, n-hexanol, n-heptanol, n-octanol, n-decanol, n-dodecanol (lauryl alcohol), 2-ethylhexanol , n-pentanol, stearyl alcohol, cetyl alcohol, lauryl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 1,3-propanediol monomethyl ether, cyclopentanol, cyclohexanol, cyclooctanol, cyclododecanol, trimethylolpropane, neopentyl glycol, pentaerythritol, 1,4-butanediol, 1,6 Hexanediol, 1,3-propanediol, 2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylglycol, tetraethylene glycol, pentaethylene glycol, Eq ycerin, 1,2-dihydroxypropane, 2,2-dimethyl-1,2-ethanediol, 1,2-butanediol, 1,4-butanediol, 3-methylpentane-1,5-diol, 2-ethyl- hexane-1,3-diol, 2,4-diethyloctane-1,3-diol, neopentyl glycol hydroxypivalate, ditrimethylolpropane, dipentaerythritol, 2,2-bis (4-hydroxycyclohexyl) propane, 1,1-, 1 , 2-, 1, 3- and 1, 4-cyclohexane-dimethanol, 1, 2, 1, 3 or 1, 4-cyclohexanediol or mixtures thereof can be obtained. These urethane and / or allophanate-containing polyisocyanates generally have an NCO content of 12 to 20 wt .-% and an average NCO functionality of 2.5 to 4.5. ) Oxadiazintriongruppen containing polyisocyanates, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such oxadiazinetrione-containing polyisocyanates are accessible from diisocyanate and carbon dioxide. ) Iminooxadiazinedione polyisocyanates, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such iminooxadiazine-dione-containing polyisocyanates can be prepared from diisocyanates by means of special catalysts. ) Uretonimine-modified polyisocyanates. Carbodiimide-modified polyisocyanates. ) Hyperbranched polyisocyanates, as they are known for example from DE-A1 10013186 or DE-A1 10013187. 0) polyurethane-polyisocyanate prepolymers, of di- and / or polyisocyanates with alcohols. 1) polyurea-polyisocyanate prepolymers. The polyisocyanates 1) to 1 1) can be used in admixture, optionally also in admixture with diisocyanates.

In a preferred embodiment of the present invention, the component (Aa) is a polyisocyanate and is selected from the group consisting of isocyanurates, biurets, urethanes and allophanates, preferably from the group consisting of isocyanurates, urethanes and allophanates , particularly preferably from the group consisting of isocyanurates and allophanates. The proportion of other groups which form from isocyanate groups, especially isocyanurate, biuret, uretdione, iminooxadiazinetrione and / or carbodiimide groups, plays a subordinate role according to the invention.

In a further preferred embodiment, component (Aa) is isocyanurate-group-containing polyisocyanates. The isocyanato-isocyanurates generally have an NCO content of 10 to 30 wt .-%, in particular 15 to 25 wt .-% and an average NCO functionality of 2.6 to 8.

In a preferred embodiment of the invention, the polyurethanes (A) according to the invention have virtually no free isocyanate groups, ie. the content of free isocyanate groups is less than 0.5% by weight, preferably less than 0.3, particularly preferably less than 0.2, very particularly preferably less than 0.1, in particular less than 0.05 and especially 0% by weight. As a result of the preparation, polyisocyanates (Aa) may still have a small proportion of the monomeric diisocyanate on which they are based, for example up to 5% by weight, more preferably up to 3% by weight, very preferably up to 2, in particular up to 1, especially up to 0, 5 and even up to 0.25% by weight. Suitable components (Ab) according to the invention are compounds which carry at least one isocyanate-reactive group and at least one free-radically polymerizable group.

In a preferred embodiment of the invention, the compound (Ab) is compounds with exactly one isocyanate-reactive group. The number of the radically polymerizable unsaturated group is at least one, preferably one to five, more preferably one to four, and most preferably one to three radically polymerizable unsaturated groups. The components (Ab) preferably have a molecular weight of below 10000 g / mol, more preferably below 5000 g / mol, very preferably below 4000 g / mol and in particular below 3000 g / mol. Specific compounds (Ab) have a molecular weight below 1000 or even below 600 g / mol. Isocyanate-reactive groups can be, for example, -OH, -SH, -NH 2 and -NHR ⁵ , where R ^{5 is} hydrogen or an alkyl group containing 1 to 4 carbon atoms, such as, for example, methyl, ethyl, n-propyl, / so-propyl, n- Butyl, / so-butyl, se / butyl or feri-butyl, means. Isocyanate-reactive groups may be preferably -OH, -IMH2 or -NHR ^5, more preferably -OH or -NH 2, and most preferably -OH.

Components (Ab) may e.g. Monoesters of α, β-unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, acrylamidoglycolic acid, methacrylamidoglycolic acid or vinyl ethers with diols or polyols, preferably having 2 to 20 C atoms and at least two hydroxyl groups such as ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, 1, 1-dimethyl-1, 2-ethanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, tripropylene glycol, 1, 2, 1,1,3- or 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, 2-ethyl-1,4-butanediol, 1,4 Dimethylolcyclohexane, 2,2-bis (4-hydroxycyclohexyl) propane, glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, ditrimethylolpropane, erythritol, sorbitol, poly-THF having a molecular weight between 162 and 2000, poly-1, 3-propanediol with a molecular weight between 134 and 400 or polyethylene glycol kol with a molecular weight between 238 and 458. Furthermore, esters or amides of (meth) acrylic acid with Amio noalkoholen z. For example, 2-aminoethanol, 2- (methylamino) ethanol, 3-amino-1-propanol, 1-amino-2-propanol or 2- (2-aminoethoxy) ethanol, 2-mercaptoethanol or polyaminoalkanes, such as ethylenediamine or diethylenetriamine , or vinyl acetic acid.

Also suitable are unsaturated polyether or polyesterols or polyacrylate polyols having an average OH functionality of 2 to 10, although less preferred.

Examples of amides of ethylenically unsaturated carboxylic acids with amino alcohols are hydroxyalkyl (meth) acrylamides such as N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-hydroxyethylacrylamide, N-hydroxymethylmethacrylamide, 5-hydroxy-3-oxapentyl (meth) acrylamide, N-hydroxyalkylcrotonamides such as N-hydroxymethylcrotonamide or N-hydroxyalkyl maleinimides such as N-hydroxyethylmaleimide.

Preference is given to using 2-hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, 1,5-pentanediol mono (meth) acrylate , 1, 6-hexanediol mono (meth) acrylate, glycerol mono- and di (meth) acrylate, trimethylolpropane mono- and di (meth) acrylate, pentaerythritol mono-, di- and tri (meth) acrylate and 4-hydroxybutyl vinyl ether, 2 Aminoethyl (meth) acrylate, 2-aminopropyl (meth) acrylate, 3-aminopropyl (meth) acrylate, 4-aminobutyl (meth) acrylate, 6-aminohexyl (meth) acrylate, 2-thioethyl (meth) acrylate, 2-aminoethyl (meth) acrylamide, 2-aminopropyl (meth) acrylamide, 3-aminopropyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, 2-hydroxypropyl (meth) acrylamide or 3-hydroxypropyl (meth) acrylamide. Particularly preferred are 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2- or 3-hydroxypropyl acrylate, 1,4-butanediol monoacrylate, 3- (acryloyloxy) -2-hydroxy propyl (meth) acrylate and the monoacrylates of polyethylene glycol of molecular weight from 106 to 238.

Suitable components (Ac) are compounds which have at least two, preferably just two, isocyanate-reactive groups, for example -OH, -SH, -IMH2 or -NHR ⁵ , in which R ⁵ is independently of one another hydrogen, methyl, ethyl, / so-propyl, n-propyl, n-butyl, / so-butyl, se / butyl or feri-butyl.

Isocyanate-reactive groups may be preferably -OH, -IMH2 or -NHR ^5, more preferably -OH or -IMH2 and most preferably -OH.

These are preferably 2 to 20 carbon diols, e.g. Ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 1-dimethylethane-1, 2-diol, 2-butyl-2-ethyl-1,3-propanediol, 2-ethyl-1, 3 Propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, hydroxypivalic acid neopentyl glycol ter, 1, 2-, 1, 3- or 1, 4-butanediol, 1, 6-hexanediol, 1, 10-decanediol, bis (4 -hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol, 1,2,3,1- or 1,4-cyclohexanediol, cyclooctanediol, norbornenediol, pinanediol, decalin diol, 2-ethyl-1,3-hexanediol, 2,4-diethyl -Octane-1, 3-diol, hydroquinone, bisphenol A, bisphenol F, bisphenol B, bisphenol S, 2,2-bis (4-hydroxycyclohexyl) propane, 1, 1, 1, 2, 1, 3 - And 1, 4-cyclohexanedimethanol, 1, 2, 1, 3 or 1, 4-cyclohexanediol, poly-THF having a molecular weight between 162 and 2000, poly-1, 2-propanediol or poly-1, 3-propanediol having a molecular weight between 134 and 1 178 or polyethylene glycol having a molecular weight between 106 and 2000 and aliphatic diamines such as methylene, and isopropylidene-bis (cyclohexylamine), pipera zin, 1, 2-, 1, 3- or 1, 4-diaminocyclohexane, 1, 2-, 1, 3- or 1, 4-cyclohexane-bis (methylamine), etc., dithiols or polyfunctional alcohols, secondary or primary amino alcohols, such as ethanolamine, monopropanolamine, etc., or thioalcohols, such as thioethylene glycol.

Polyester polyols are e.g. from Ullmann's Encyclopedia of Industrial Chemistry,

4th edition, Volume 19, pp. 62 to 65 known. Preference is given to using polyesterpolyols which are obtained by reacting dihydric alcohols with dibasic carboxylic acids. Instead of the free polycarboxylic acids, it is also possible to use the corresponding polycarboxylic anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof to prepare the polyesterpolyols. The polycarboxylic acids may be aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic and optionally, e.g. by halogen atoms, substituted and / or unsaturated. Examples include:

Oxalic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, o-phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, azelaic acid, 1,4-cyclohexanedicarboxylic acid or tetrahydrophthalic acid, suberic acid, azelaic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, Endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleic anhydride, dimer fatty acids, their isomers and hydrogenation products and esterifiable derivatives such as anhydrides or dialkyl esters, for example C 1 -C 4 -alkyl esters, preferably methyl, ethyl or n-butyl esters, of the acids mentioned are used. Prefers are dicarboxylic acids of the general formula HOOC- (CH 2) _y -COOH, where y is a number from 1 to 20, preferably an even number from 2 to 20, particularly preferably succinic acid, adipic acid, sebacic acid and dodecanedicarboxylic acid. Suitable polyhydric alcohols for the preparation of polyesterols into consideration

 1, 2-propanediol, ethylene glycol, 2,2-dimethyl-1,2-ethanediol, 1,3-propanediol, 1,2-butanediol,

1, 3-butanediol, 1, 4-butanediol, 3-methylpentane-1, 5-diol, 2-ethylhexane-1, 3-diol, 2,4-diethyloctane-1, 3-diol, 1,6-hexanediol, Poly-THF with a molecular weight between 162 and 2000, poly-1,3-propanediol with a molecular weight between 134 and 1 178, poly-1,2-propanediol with a molecular weight between 134 and 898, polyethylene glycol with a molecular weight between 106 and 458, neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, 2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-bis (4-hydroxycyclohexyl) propane, 1, 1 -, 1, 2-, 1, 3- and 1, 4-cyclohexanedimethanol, 1, 2-, 1, 3- or 1, 4-cyclohexanediol, trimethylolbutane, trimethylolpropane, trimethylolethane, neopentyl glycol, pentaerythritol, glycerol, ditrimethylolpropane, dipentaerythritol, sorbitol, Mannitol, diglycerol, threitol, erythritol, adonite (ribitol), arabitol (lyxite), xylitol, dulcitol (galactitol), maltitol or isomalt, which may optionally be alkoxylated as described above.

Alcohols of the general formula HO- (CH 2) x -OH are preferred, where x is a number from 1 to 20, preferably an even number from 2 to 20. Preferred are ethylene glycol, butane-1, 4-diol, hexane-1, 6-diol, octane-1, 8-diol and dodecane-1, 12-diol. Further preferred is neopentyl glycol.

Also included are polycarbonate diols, e.g. by reaction of phosgene with an excess of those mentioned as synthesis components for the polyester polyols low molecular weight alcohols, into consideration.

Also suitable are lactone-based polyesterdiols, which are homopolymers or copolymers of lactones, preferably terminal hydroxyl-containing addition products of lactones onto suitable difunctional starter molecules. Suitable lactones are preferably those which are derived from compounds of the general

Derive formula HO- (CH 2) _z -COOH, wherein z is a number from 1 to 20 and an H atom of a methylene unit may also be substituted by a C 1 to C ₄ alkyl radical. Examples are ε-prolactone, β-propiolactone, gamma-butyrolactone and / or methyl-e-caprolactone, 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid or pivalolactone, and mixtures thereof. Suitable starter components are, for example, the low molecular weight dihydric alcohols mentioned above as the synthesis component for the polyesterpolyols. The corresponding polymers of ε-caprolactone are particularly preferred. Lower polyester diols or polyether diols can also be used as starters for the preparation of the lactone polymers. Instead of the polymers of lactones, it is also possible to use the corresponding, chemically equivalent polycondensates of the hydroxycarboxylic acids corresponding to the lactones. Particularly suitable here are the cycloaliphatic diols, such as bis (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol, 1, 2-, 1, 3- or 1, 4-cyclohexanediol, 1, 1 -, 1, 2, 1, 3rd - And 1, 4-cyclohexanedimethanol, cyclooctanediol or norbornanediol. Compounds (Ac) having more than two isocyanate-reactive groups may preferably be 2 to 20 carbon atoms, for example trimethylolbutane, trimethylolpropane, trimethylolethane, pentaerythritol, glycerol, ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, diglycerol, threitol, erythritol, adonite (Ribit), arabitol (lyxite), xylitol, dulcitol (galactitol), maltitol, isomalt, particularly preferred are trimethylolpropane, pentaerythritol and glycerol, and most preferably trimethylolpropane.

Optional components (Ae) are those with optionally at least one compound having exactly one isocyanate-reactive group. These are preferably monools, particularly preferably alkanols and very particularly preferably alkanols having 1 to 20, preferably 1 to 12, particularly preferably 1 to 6, very particularly preferably 1 to 4 and in particular 1 to 2 carbon atoms.

Examples are methanol, ethanol, / so-propanol, n-propanol, n-butanol, / so-butanol, sec-butanol, ferf-butanol, n-hexanol, n-heptanol, n-octanol, n-decanol, n Dodecanol (lauryl alcohol), 2-ethylhexanol, cyclopentanol, cyclohexanol, cyclooctanol, cyclododecanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol, 1, 3-propanediol monomethyl ether, preferred are methanol, ethanol, / so-propanol, n-propanol , n-butanol, feri-butanol, n-hexanol, 2-ethylhexanol, cyclopentanol, cyclohexanol, and cyclododecanol, particularly preferred are methanol, ethanol, / so-propanol, n-propanol, n-butanol and ferf-butanol, most preferred are methanol and ethanol and especially methanol.

In a preferred embodiment, the monools may be the stated cycloaliphatic alcohols, preferably cyclopentanol or cyclohexanol, more preferably cyclohexanol.

In a further preferred embodiment, the monools can be the stated aliphatic alcohols having 6 to 20 carbon atoms, particularly preferably those having 8 to 20 carbon atoms, very particularly preferably those having 10 to 20 carbon atoms.

 In a particularly preferred embodiment, the monools are the aliphatic alcohols mentioned, very particularly preferably those having 1 to 4 carbon atoms, in particular methanol.

(Ag) the obligatory compounds (Ag) are those which have at least one isocyanate-reactive group and at least one dispersive group. Compounds preferred as component (Ag) have at least one, preferably exactly one isocyanate-reactive group and exactly one dispersive group.

The dispersing active groups may preferably be (Ag1) anionic or anionic group convertible groups.

Compounds (Ag1) contain exactly one isocyanate-reactive group and at least one anionic or anionic group-transferable hydrophilic group. These are, for example, those described in EP-A1 703 255, there especially of p. 3, Z. 54 to p. 4, Z. 38, in DE-A1 197 24 199, there especially of S 3, Z. 4 to Z. 30, in DE-A1 40 10 783, there especially of Sp. 3, Z. 3 to Z. 40, in DE-A1 41 13 160, there especially of Sp. 3 , Z. 63 to Sp. 4, Z. 4 and in EP-A2 548 669, where they are described in particular by S. 4, Z. 50 to S. 5, Z. 6. These documents are hereby incorporated by reference in the context of the present disclosure.

Preferred compounds (Ag1) are those having the general formula

RG-R ³ -DG wherein

 RG is at least one isocyanate-reactive group,

DG at least one dispersive group and

R ^{3 is} an aliphatic, cycloaliphatic or aromatic radical containing 1 to 20 carbon atoms.

Examples of isocyanate-reactive groups RG are -OH, -SH, or -NHR -IMH2 ^5, wherein R ⁵ has the meaning given above, but may be different from the radical used there are preferably -OH, or -NHR -IMH2 ⁵ , particularly preferred are -OH or -IMH2, and most preferably -OH.

Examples of DG are -COOH, -SO3H or -PO3H and their anionic forms to which any counterion may be associated, for example Li ⁺ , Na ⁺ , K ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ or Ba ²⁺ . Furthermore, as a counterion of ammonia or amines, especially tertiary amines, derived ammonium ions or quaternary ammonium ions, such as ammonium, methylammonium, dimethylammonium, trimethylammonium, ethylammonium, diethylammonium, triethylammonium, tributylammonium, di- / so-propyl-ethyl-ammonium , Benzyldimethylammonium, monoethanolammonium, diethanolammonium, triethanolammonium, hydroxyethyldimethylammonium, hydroxyethyldiethylammonium, monopropanolammonium, dipropanolammonium, tripropanolammonium, piperidinium, piperazinium, Ν, Ν'-dimethylpiperazinium, morpholinium, pyridinium, tetramethylammonium, triethylmethylammonium, 2-hydroxyethyl- Trimethylmonium, bis- (2-hydroxyethyl) -dimethylammonium, tris (2-hydroxyethyl) methyl-mmonium, may be associated as a counterion. R ³ is preferably methylene, 1,2-ethylene, 1,2-propylene, 1,3-propylene, 1,2-butylene, 1,4-butylene, 1,3-butylene, 1,6-hexylene, 1, 8-octylene, 1, 12-dodecylene, 1, 2-phenylene, 1, 3-phenylene, 1, 4-phenylene, 1, 2-naphthylene, 1, 3-naphthylene, 1, 4-naphthylene, 1, 6-naphthylene, 1,2-cyclopentylene, 1,3-cyclopentylene, 1,2-cyclohexylene, 1,3-cyclohexylene or 1,4-cyclohexylene.

Preferably, the component (Ag1) is e.g. hydroxyacetic, tartaric, lactic, 3-hydroxypropionic, hydroxypivalic, mercaptoacetic, mercaptopropionic, thiolactic, mercaptosuccinic, glycine, iminodiacetic, sarcosine, alanine, β-alanine, leucine, isoleucine, aminobutyric, malic, hydroxydecanoic , 12-hydroxystearic acid, aminonaphthalenecarboxylic acid, hydroxethanesulfonic acid, hydroxypropanesulfonic acid, mercaptoethanesulfonic acid, mercaptopropanesulfonic acid, aminomethanesulfonic acid, taurine, aminopropanesulfonic acid, N-alkylated or N-cycloalkylated aminopropane- or -ethanesulfonic acids, for example N-cyclohexylaminoethanesulfonic acid or N-cyclohexylaminopropanesulfonic acid , as well as their alkali metal or alkaline earth ammonium salts and particularly preferably the monohydroxycarboxylic and -sulfonic acids as well as monoaminocarboxylic and -sulfonic acids.

Further preferred compounds (Ag1) are those having precisely one dispersively active group DG and at least two isocyanate-reactive group RG, whereby here too

DG is -COOH, -SO3H or -POsH and their anionic forms, to which any counterion may be associated, preferably DG is -COOH groups and wherein here too the reactive groups RG -OH, -SH, -IMH2 or -NHR ⁵ where R ^{5 is} as defined above, preferred are -OH, -IMH 2 or -NHR ⁵ , more preferred are -OH or -IMH 2 and most preferred is -OH.

Examples thereof are dimethylolpropionic acid, dimethylolbutyric acid, trimethylolacetic acid, 3,5-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,4-dihydroxy-3,6-dimethylbenzoic acid, sugar acids, 4 Amino-2-hydroxybenzoic acid, 5-amino-2-hydroxybenzoic acid, 3,5-diaminobenzoic acid, 1-amino-2-hydroxynaphthalene-4-sulfonic acid, 4,5-dihydroxynaphthalene-2,7-disulfonic acid, 4 Amino-5-hydroxynaphthalene-2,7-disulfonic acid and gallic acid, preferred are dimethylolpropionic acid, dimethylolbutyric acid and trimethylolacetic acid, particularly preferred is dimethylolpropionic acid. To prepare the dispersion, the abovementioned acids, if they are not already salts, are partially or completely neutralized, preferably with alkali metal salts or amines, preferably tertiary amines.

In order to achieve a good dispersing activity, the polyurethanes according to the invention preferably have a density of the dispersing anionic group-carrying molecules of 1 to 25 mol% based on a functional group and isocyanate groups, preferably at least 3 mol% and particularly preferably from 5 to 15 mol% , The polyurethanes which can be used according to the invention are obtained by reacting components (Aa), (Ab) and (Ag) and optionally (Ac) and / or (Ae) with one another.

The molar composition (Aa) :( Ab): (Ac): (Ae) :( Ag) per 1 mol of reactive

Isocycanate groups in (Aa) usually as follows:

(Ab) 1-50, preferably 5-40, more preferably 10-37.5 and especially

 15-33 mol% of isocyanate-reactive groups,

 (Ac) 0-50, preferably 0-30, more preferably 0-25 and especially

 0-20 mol% of isocyanate-reactive groups,

 (Ae) 0-5, preferably 0-4, particularly preferably 0-3 and in particular

 0-2 mol% of isocyanate-reactive groups,

 (Ag) 1 to 25, preferably 2 to 20, particularly preferably 3 to 15 and in particular

 5-15 mol% of isocyanate-reactive groups, with the proviso that the sum of the isocyanate-reactive groups corresponds to the number of isocyanate groups in (Aa).

The formation of the adduct of isocyanate group-containing compound and the compound containing isocyanate-reactive groups is generally carried out by mixing the components in any order, optionally at elevated temperature.

In this case, the compound containing isocyanate-reactive groups is preferably added to the compound containing isocyanate groups, preferably in several steps.

The isocyanate group-containing compound is more preferably initially introduced, and the compounds containing isocyanate-reactive groups are added. In particular, the isocyanate group-containing compound (Aa) is initially introduced and then (Ab) and / or (Ag) are added. Subsequently, optionally desired further components can be added.

In general, the reaction is carried out at temperatures between 5 and 100 ° C, preferably between 20 to 90 ° C and more preferably between 40 and 80 ° C and in particular between 60 and 80 ° C.

 Preference is given to working under anhydrous conditions during the preparation of the polyurethane.

Anhydrous here means that the water content in the reaction system is not more than 5% by weight, preferably not more than 3% by weight and particularly preferably not more than 1% by weight, very particularly preferably not more than 0.75 and in particular not more than 0, 5% by weight.

The reaction is preferably carried out in the presence of at least one oxygen-containing gas, for example air or air-nitrogen mixtures or mixtures of oxygen or an oxygen-containing gas with a gas which is inert under the reaction conditions and which has an oxygen content. have substance content of less than 15, preferably less than 12, more preferably less than 10, most preferably less than 8 and in particular less than 6% by volume.

The reaction may also be carried out in the presence of an inert solvent, e.g. Acetone, / sobutyl methyl ketone, toluene, xylene, butyl acetate, methoxypropyl acetate or ethoxyethyl acetate. Preferably, however, the reaction is carried out in the absence of a solvent.

In a preferred embodiment, the reaction of (Aa) with (Ab) can be carried out under allophanatization conditions.

Typical catalysts for such a reaction are organozinc compounds, such as zinc acetylacetonate or zinc 2-ethylcaproate, or a tetraalkylammonium compound, such as N, N, N-trimethyl-N-2-hydroxypropylammonium hydroxide or N, N, N-trimethyl-N-2-hydroxypropylammonium 2-ethylhexanoate, or organotin compounds such as dibutyltin dilaurate.

As catalysts these preferably bismuth, zinc and / or titanium-containing compounds, preferably a bismuth and / or titanium-containing compound and more preferably a bismuth-containing compound.

Suitable zinc and bismuth compounds are those in which the following anions are used: F ^" , CI ^" , CIO ^" , CIO ₃ ^" , CIO ₄ ^" , Br ^" , J ^" , J0 ₃ ^" , CN ^" , OCN ^" , NO ₂ ^" , NO ₃ ^" , HCO ₃ ^- , CO, ^2" , S ² -, SH-, HSCV, SO, ^{2 "} , HSO ₄ -, SO ₄ ^2" , S ₂ O ₂ ² -, S ₂ 0 ₄ ² -, S ₂ 0 ₅ ² -, S ₂ 0 ₆ ² -, S ₂ 0 ₇ ² -, S ₂ 0 ₈ ² -, H ₂ P0 ₂ -, H ₂ P0 ₄ -, HP0 ₄ ^{2 "} , P0 ₄ ^3" , P ₂ 0 ₇ ⁴ -, (OC _n H _{2n + 1} ) -, (C _n H ^ O,) ^" , (C _n H _2n _ ₃ 0 ₂ ) - as well as (C _{n +} iH _2n _ ₂ 0 ₄ ) ^{2 "} , where n is the numbers 1 to 20. Preference is given here to the carboxylates in which the anion satisfies the formulas (C _n H _2n _ ₁ O ₂ ) ^" and (C _n + iH _2n _ ₂ 0 ₄ ) ^{2 "} with n being equal to 1 to 20. Particularly preferred salts have, as anions, monocarboxylates of the general formula (C _n H _2n _ ₁ O ₂ ) ^" , where n is the numbers 1 to 20. Particular mention should be made here of format, acetate, propionate, hexanoate, neodecanoate and 2-ethylhexanoate.

Among the zinc catalysts, the zinc carboxylates are preferred, more preferably those of carboxylates having at least six carbon atoms, most preferably at least eight carbon atoms, especially zinc (II) diacetate or zinc (I) d ioctoate or zinc (II) neodecanoate. Commercially available catalysts are, for example, Borchi® Kat 22 from OMG Borchers GmbH, Langenfeld, Germany.

Among the bismuth catalysts bismuth carboxylates are preferred, more preferably those of carboxylates having at least six carbon atoms, in particular bismuth octoate, -ethylhexanoate, -neodecanoate, or -pivalate; for example, K-KAT 348, XC-B221; XC-C227, XC 8203 and XK-601 from King Industries, TIB KAT 716, 716LA, 716XLA, 718, 720, 789 from TIB Chemicals and those from Shepherd Lausanne, and, for example, Borchi® Kat 24; 315; 320 from OMG Borchers GmbH, Langenfeld, Germany. These may also be mixtures of different metals, as for example in Borchi® Kat 0245 from OMG Borchers GmbH, Langenfeld, Germany

Among the titanium compounds, the titanium tetra-alcoholates Ti (OR) _{4 are} preferred, more preferably those of alcohols ROH having 1 to 8 carbon atoms, for example, methanol, ethanol, / so-propanol, n-propanol, n-butanol, etc. Butanol, se / butenol, ie / f-butanol, n-hexanol, n-heptanol, n-octanol, are preferably methanol, ethanol, / so-propanol, n-propanol, n-butanol, ie f- Butanol, particularly preferred are iso-Pro-panol and n-butanol. In a further preferred embodiment, such compounds are used, as described in WO 00/39183, p. 4, Z. 3 to p. 10, Z. 19, the disclosure of which is herewith part of the present document. Particularly preferred among these are those compounds which have as structural components at least one (cyclo) aliphatic isocyanate containing allophanate groups and at least one hydroxyalkyl (meth) acrylate, very particularly preferably the product Nos. 1 to 9 in Table 1 on page 24 of WO 00/39183.

Water-dispersible compound (B)

According to the invention, the compound (B) has at least two mercapto groups, for example two to six, preferably two to four and particularly preferably three to four.

Suitable mercapto groups according to the invention are -SH groups, especially those which are bonded to tertiary carbon atoms, methine groups or methylene groups, particularly preferably those which are bonded to methylene groups.

Preferred compounds (B) have a number average molecular weight M _n of at least 750 g / mol, preferably at least 1000 g / mol, more preferably at least

1250 g / mol and most preferably at least 1500 g / mol. As a rule, a molecular weight M _n of 5000 g / mol should not be exceeded, preferably not more than 4500, particularly preferably not more than 4000, very particularly preferably not more than 3500 and in particular not more than 3000 g / mol.

The molecular weight indicated makes it possible to keep the typical odor of the mercapto compounds as low as possible.

In a preferred embodiment, the compound (B) is a water-dispersible and mercapto-containing polyurethane, composed of the components (Ba) at least one organic aliphatic or cycloaliphatic di- or polyisocyanate, (Bc) optionally at least one compound having at least two isocyanate-reactive groups, (Bg) at least one compound which has at least one isocyanate-reactive group and at least one dispersive-active group,

(Be) optionally at least one compound with exactly one isocyanate-reactive

Group and

(Bf) at least one compound having at least two mercapto groups.

The compounds (Ba) may in principle be the same compounds as listed above under the compounds (Aa). In a preferred embodiment, the compound (Ba) is monomeric diisocyanates, particularly preferably hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate and 4,4'- or 2,4'-di ( isocyanatocyclohexyl) methane, most preferably isophorone diisocyanate. The optional compound (Bc) is at least one compound having at least two isocyanate-reactive groups, preferably 2 to 6, more preferably 2 to 4, most preferably 2 to 3 and especially exactly 2 isocyanate-reactive groups. These may in principle be the same compounds as listed above under (Ac).

In a preferred embodiment, the compounds (Bc) are aliphatic or cycloaliphatic diols having 2 to 20 carbon atoms, for example ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 1-dimethylethane-1, 2-diol , 2-butyl-2-ethyl-1,3-propanediol,

2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, 1, 2, 1, 3 or 1, 4-butanediol, 1, 6-hexanediol, 1, 10-decanediol, bis (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol, 1, 2-, 1, 3- or 1, 4-cyclohexanediol, cyclooctanediol, norbornanediol, pinanediol, decalindiol, 2-ethyl-1,3 Hexanediol, 2,4-diethyl-octane-1,3-diol, 2,2-bis (4-hydroxycyclohexyl) propane, 1,1,1,2,2,3,4-cyclohexanedimethanol, 1, 2-, 1, 3- or 1, 4-cyclohexanediol, poly-THF having a molecular weight between 162 and 2000, poly-1, 2-propanediol or poly-1, 3-propanediol having a molecular weight between 134 and 1 178th or polyethylene glycol having a molecular weight between 106 and 2000. In a further preferred embodiment, the compounds (Bc) are polyester diols having a number average molecular weight M _{n of} less than 3000 g / mol, preferably less than 2500 g / mol and more preferably less than 2000 g / mol.

These polyester diols are particularly preferably reaction products of aliphatic or cycloaliphatic, preferably aliphatic, dicarboxylic acids with aliphatic or cycloaliphatic diols. Examples of dicarboxylic acids are oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid, 1,4-cyclohexanedicarboxylic acid or tetrahydrophthalic acid, suberic acid, azelaic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, glutaric anhydride, and esterifiable derivatives, such as anhydrides or dialkyl esters, for example C 1 -C 4 -alkyl esters, preferably methyl, ethyl or n-butyl esters, of the acids mentioned are used. Preference is given to dicarboxylic acids of the general formula HOOC- (CH 2) _y -COOH, where y is a number from 1 to 20, preferably an even number from 2 to 20, particularly preferably succinic acid, adipic acid, sebacic acid and dodecanedicarboxylic acid.

Examples of diols are ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 1-dimethylethane-1, 2-diol, 2-butyl-2-ethyl-1, 3-propanediol, 2-ethyl-1, 3-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, 1, 2, 1, 3 or 1, 4-butanediol, 1, 6-hexanediol, 1, 10-decanediol, bis- (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol, 1, 2-, 1, 3- or 1, 4-cyclohexanediol, cyclooctanediol, norbornanediol, pinanediol, decalindiol, 2-ethyl-1, 3-hexanediol, 2,4-diethyl-octane 1, 3-diol, 2,2-bis (4-hydroxycyclohexyl) propane, 1, 1, 1, 2, 1, 3 and 1, 4-cyclohexanedimethanol, 1, 2, 1, 3 or 1, 4-cyclohexanediol.

The at least one compound (Bg) which has at least one isocyanate-reactive group and at least one dispersively active group may in principle be the same groups as listed above under (Ag), preferably as listed under (Ag1).

In addition to the compounds listed under (Ag1), the compound (Bg) may also be those compounds which have more than one isocyanate-reactive group and exactly one group DG.

Examples of the latter are dimethylolpropionic acid, dimethylolbutyric acid and trimethylolacetic acid, preference is given to dimethylolpropionic acid and dimethylolbutyric acid and dimethylolpropionic acid is particularly preferred.

Preferred compounds (Bg) are hydroxyacetic acid, lactic acid, 3-hydroxypropionic acid, hydroxypivalic acid, mercaptoacetic acid, mercaptopropionic acid, glycine, iminodiacetic acid, sarcosine, alanine, β-alanine, hydroxethanesulfonic acid, hydroxypropanesulfonic acid, taurine, aminopropanesulfonic acid, N-alkylated or N-cycloalkylated aminopropane or ethanesulfonic acids, for example N-cyclohexylaminoethanesulfonic acid or N-cyclohexylaminopropanesulfonic acid, and dimethylolpropionic acid.

The compound (Bg) is particularly preferably selected from the group consisting of dimethylolpropionic acid, hydroxypivalic acid, glycolic acid and thioglycolic acid. In the optional, at least one compound (Be) with exactly one isocyanate-reactive group may in principle be such compounds, as listed above under (Ae). The compound (Be) is preferably alkanols having 1 to 20, preferably 1 to 12, particularly preferably 1 to 6, very particularly preferably 1 to 4 and in particular 1 to 2 carbon atoms.

Particularly preferred are methanol, ethanol, / so-propanol, n-propanol, n-butanol, / so-butanol, se / butanol, feri-butanol, very particularly preferably methanol, ethanol or n-butanol and especially to methanol.

The at least one compound (Bf) is a compound having at least two, for example two to six, preferably two to five, particularly preferably two to four mercapto groups.

Conceivable compounds (Bf) with at least one, preferably exactly one hydroxyl primary or secondary amino group and at least two mercapto groups. However, preference is given to compounds (Bf) which contain only mercapto groups as reactive groups.

Examples of such compounds are di-, tri- and Polymercaptoalkane. In a preferred embodiment, the compounds (Bf) are reaction products of alcohols having the corresponding desired functionality with 2-mercaptoacetic acid or 3-mercaptopropionic acid or derivatives thereof.

In order to obtain dimercaptans, diols are used accordingly, for trimercaptans triols, etc.

Examples of such correspondingly functional alcohols are listed under the compounds (Ac). These alcohols are preferably 1,2-propanediol, ethylene glycol, 2,2-dimethyl-1,2-ethanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4. Butanediol, 3-methylpentane-1, 5-diol, 2-ethylhexane-1, 3-diol, 2,4-diethyloctane-1, 3-diol, 1, 6-hexanediol, poly-THF having a molecular weight between 162 and 2000 , Poly-1, 3-propanediol with a molecular weight between 134 and 1 178, poly-1, 2-propanediol with a molecular weight between 134 and 898, polyethylene glycol having a molecular weight between 106 and 458, neopentyl glycol, hydroxypivalates neopentylglyk- lester, 2-ethyl -1, 3-propanediol, 2-methyl-1, 3-propanediol, 2,2-bis (4-hydroxycyclohexyl) propane, 1, 1, 1, 2, 1, 3 and 1, 4-cyclohexanedimethanol, 1, 2-, 1, 3- or 1, 4-cyclohexanediol, trimethylolbutane, trimethylolpropane, trimethylolethane, neopentyl glycol, pentaerythritol, glycerol, ditrimethyl lolpropane, dipentaerythritol, sorbitol, mannitol, diglycerol, threitol, erythritol, adonite (ribitol), arabitol (lyxite), xylitol, dulcitol (galactitol), maltitol or isomalt, which may optionally be alkoxylated as described above. In a particularly preferred embodiment, the compounds (Bf) are compounds of the formula

wherein

R ¹ , R ^{2 are} each independently hydrogen or a C ¹ to C ⁴ alkyl radical,

R ^{4 is} methylene or 1, 2-ethylene, k, I, m, q, each independently zero or a positive integer from 1 to 5, preferably zero or a positive integer from 1 to 4 and particularly preferably zero or a positive integer from 1 to 3, each Yi for i = 1 to k, 1 to I, 1 to m and 1 to q, independently selected from the group consisting of -CH ₂ -CH ₂ -O-, -CH ₂ -CH (CH ₃ ) -O-, -CH (CH ₃ ) -CH ₂ -O-, -CH ₂ -C (CH ₃ ) ₂ -O-, -C (CH ₃ ) ₂ -CH ₂ -O -, CH ₂ -CHVin-O-, -CHVin-CH ₂ -0-, -CH ₂ -CHPh-O- and -CHPh-CH ₂ -O-, preferably from the group -CH ₂ -CH ₂ -O -, CH ₂ -CH (CH ₃ ) -O- and

-CH (CH ₃ ) -CH ₂ -O-, and more preferably -CH ₂ -CH ₂ -O- wherein Ph is phenyl and Vin is vinyl.

Very particular preference is given to compounds (Bf) selected from the group consisting of pentaerythritol tetra- (3-mercaptopropionate) (PETMP), ethylene glycol di (3-mercaptopropionate) (GDMP), trimethylolpropane tri- (3-mercaptopropionate) (TMPMP), trimethylolpropane trimercap - toacetate (TMPMA), pentaerythritol tetramercaptoacetate (PETMA), 3-mercaptopropionic acid ester of poly-1, 2-propylene glycol of molecular weight 500 to 2500 g / mol or 3-mercaptopropionic acid ester of ethoxylated trimethylolpropane of molecular weight up to 1500 g / mol.

The polyurethanes (B) are prepared analogously to those of the polyurethanes (A). The acid groups in the polyurethanes (B) can be partially or completely neutralized, preferably with alkali metal salts, ammonia or amines, preferably tertiary amines, to prepare the dispersion, if they are not already salts.

To prepare the dispersions according to the invention, the polyurethanes (A) and (B) are prepared either separately from one another as aqueous dispersions and then these aqueous dispersions are mixed together or one of the polyurethanes (A) or (B) is prepared as an aqueous dispersion and the other in mixed in this aqueous dispersion thus obtained. In the so-called "prepolymer mixing process", first a prepolymer of the components (Aa) to (Ag) or (Ba) to (Bf) is prepared. This may, if necessary, be carried out in a water-miscible and boiling under normal pressure below 100 ° C solvent, preferably acetone, ethyl methyl ketone or diethyl ketone. The prepolymer is first dispersed in water and optionally simultaneously and / or subsequently by reaction of the isocyanate groups with amines which carry more than 2 isocyanate-reactive amino groups, crosslinked or with amines carry the 2 isocyanate-reactive amino groups, chain-extended. Chain extension also occurs when no amine is added. In this case, excess isocyanate groups are hydrolyzed to amine groups, which react with remaining isocyanate groups of the prepolymers with chain extension.

The average particle size (z average), measured by means of dynamic light scattering with the Malvern® Autosizer 2 C, of the dispersions prepared according to the invention is generally <200 nm, preferably <150 nm and particularly preferably <100 nm. The dispersions generally have a solids content from 10 to 75, preferably from 20 to 65 wt .-% and a viscosity of 10 to 500 m Pas (measured at a temperature of 20 ° C and a shear rate of 250 s ^_1 .

For some applications it may be useful to adjust the dispersions to another, preferably a lower, solids content, for example by dilution.

The aqueous dispersions of the polyurethanes according to the invention can be used for coating various substrates, such as. As wood, wood veneer, paper, cardboard, cardboard, textile, leather, fleece, plastic surfaces, glass, ceramics, mineral building materials, metals or coated metals.

When used in coating compositions, the polyurethanes according to the invention can be used in particular in primers, fillers, pigmented topcoats and clearcoats in the field Car repair or large vehicle paint can be used. Particularly suitable are those coating compositions for applications in which a particularly high application safety, outdoor weather resistance, optics, solvent, chemical and water resistance are required, such as in the car repair and large vehicle painting.

The coating compositions according to the invention are suitable for coating substrates such as wood, paper, textile, leather, fleece, plastic surfaces, glass, ceramics, mineral building materials, such as cement molded bricks and fiber cement boards, or metals or coated metals, preferably of plastics or metals, in particular in the form of films, more preferably metals.

The coating compositions of the invention are suitable as or in exterior coatings, ie those applications that are exposed to daylight, preferably of building parts, interior coatings, coatings on vehicles and aircraft. In particular, the coating compositions of the invention are used as or in automotive clearcoat and topcoat (s). Further preferred fields of use are can-coating and coil-coating.

They are particularly suitable as primers, fillers, pigmented topcoats and clearcoats in the field of industrial, wood, automotive, in particular OEM paintwork, or decorative paintwork. Especially suitable are the coating compositions for applications in which a particularly high application safety, outdoor weathering resistance, appearance, scratch resistance, solvent and / or chemical resistance are required.

Furthermore, the radiation-curable coating compositions may optionally contain at least one photoinitiator and / or optionally further typical lacquer additives.

Photoinitiators may be, for example, photoinitiators known to those skilled in the art, e.g. those in "Advances in Polymer Science", Volume 14, Springer Berlin 1974 or in K.K. Dieterker, Chemistry and Technology of UV and EB Formulation for Coatings, Inks and Paints, Volume 3; Photoinitiators for Free Radical and Cationic Polymerization, P.K.T. Oldring (Eds), SITA Technology Ltd, London.

Suitable examples include mono- or Bisacylphosphinoxide, as described for example in EP-A 7 508, EP-A 57 474, DE-A 196 18 720, EP-A 495 751 or EP-A 615 980, for example, 2.4 , 6-trimethylbenzoyldiphenylphosphine oxide (Lucirin® TPO from BASF AG), ethyl 2,4,6-trimethylbenzoylphenylphosphinate (Lucirin® TPO L from BASF AG), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure® 819 from Ciba Spezialitätenchemie), benzophenones, hydroxyacetophenones, phenylglyoxylic acid and its derivatives or mixtures of these photoinitiators. Examples which may be mentioned are benzophenone, acetophenone, acetonaphthoquinone, methyl ethyl ketone, valerophenone, hexanophenone, α-phenylbutyrophenone, p-morpholinopropiophenone, dibenzosuberone, 4-morpholinobenzophenone, 4-morpholinodeoxybenzoin, p-diacetylbenzene, 4-aminobenzophenone, 4'-methoxyacetophenone, β Methyl anthraquinone, ferric butyl anthraquinone, anthraquinone carboxylic acid esters, benzaldehyde, α-tetralone, 9-acetylphenanthrene, 2-acetylphenanthrene, 10-thioxanthenone, 3-acetylphenanthrene, 3-acetylindole, 9-fluorenone, 1-indanone, 1, 3,4-triacetylbenzene, thioxanthen-9-one, xanthen-9-one, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-di- / sopropylthioxanthone, 2,4-dichlorothioxanthone, benzoin , Benzoin / sobutyl ether, chloroxanthenone, benzoin tetrahydropyranyl ether, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, benzoin zsopropyl ether, 7-H-benzoin methyl ether, benz [de] anthracencene-7-one, 1-naphthaldehyde, 4,4'-bis (dimethylamino) benzophenone, 4-phenylbenzophenone, 4-chlorobenzophenone, Michler's ketone, 1-acetonaphthone, 2-acetonaphthone, 1-benzoylcyclohexan-1-ol, 2-hydroxy 2,2-dimethylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxyacetophenone, acetophenone dimethyl ketal, o-methoxybenzophenone, triphenylphosphine,

Tri-o-tolylphosphine, benz [a] anthracene-7,12-dione, 2,2-diethoxyacetophenone, benzil ketals such as benzil dimethyl ketal, 2-methyl-1 - [4- (methylthio) phenyl] -2-morpholinopropane-1 - on, anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-feri-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone and 2,3-butanedione. Also suitable are non-yellowing or slightly yellowing photoinitiators of the phenylglyoxalic acid ester type, as described in DE-A 198 26 712, DE-A 199 13 353 or WO 98/33761.

Preferred among these photoinitiators are 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphinate, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, benzophenone, 1-benzoylcyclohexan-1-ol, 2-hydroxy -2,2-dimethylacetophenone and 2,2-dimethoxy-2-phenylacetophenone.

As further paint-typical additives it is possible, for example, to use antioxidants, stabilizers, activators (accelerators), fillers, pigments, dyes, antistatic agents, flame retardants, thickeners, thixotropic agents, surface-active agents, viscosity modifiers, plasticizers or chelating agents.

Furthermore, one or more thermally activatable initiators may be added, e.g. Potassium peroxodisulfate, dibenzoyl peroxide, cyclohexanone peroxide, di-tert-butyl peroxide, azobis / so-butyronitrile, Cyclohexylsulfonylacetylperoxid, di- / sopropylpercarbonat, feri-butyl peroctoate or benzpinacol, and for example such thermally activatable initiators having a half-life at 80 ° C of more than 100 hours, such as di-t-butyl peroxide, cumene hydrochloride, dicumyl peroxide, t-butyl perbenzoate, silylated pinacols, the z. B. commercially available under the trade name ADDID 600 from Wacker or hydroxyl-containing amine-N-oxides, such as 2,2,6,6-tetramethylpiperidine-N-oxyl, 4-hydroxy-2,2,6,6- Tetramethylpiperidine N-oxyl etc.

Further examples of suitable initiators are described in "Polymer Handbook" 2nd ed., Wiley & Sons, New York.

Suitable thickeners besides free-radically (co) polymerized (co) polymers, customary organic and inorganic thickeners such as hydroxymethylcellulose or bentonite. As chelating agents, for example, ethylenediamine-acetic acid and its salts and β-diketones can be used.

Suitable fillers include silicates, e.g. For example, silicates obtainable by hydrolysis of silicon tetrachloride, such as Aerosil® from Degussa, silica, talc, aluminum silicates, magnesium silicates, calcium carbonates, etc.

Suitable stabilizers include typical UV absorbers such as oxanilides, triazines and benzotriazole (the latter being available as Tinuvin® grades from Ciba Specialty Chemicals) and benzophenones. These may be used alone or together with suitable radical scavengers, for example sterically hindered amines such as 2,2,6,6-tetramethylpiperidine, 2,6-di-tert-butylpiperidine or derivatives thereof, eg. B. bis (2,2,6,6-tetra-methyl-4-piperidyl) sebacinate used. Stabilizers are usually used in amounts of 0.1 to 5.0 wt .-%, based on the solid components contained in the preparation.

It is an advantage of the present invention that the coating compositions need not necessarily contain a solvent such as butyl acetate, ethyl acetate, methoxypropyl acetate, toluene, xylene, fluorinated aromatics, aliphatic and aromatic hydrocarbon mixtures.

According to the invention, therefore, preference is given to those coating compositions which are substantially free of organic solvents.

The coating of the substrates with the coating compositions according to the invention is carried out by conventional methods known to the person skilled in the art, wherein a coating composition according to the invention or a coating formulation comprising it is applied to the substrate to be coated in the desired thickness and optionally dried. If desired, this process can be repeated once or several times. The application to the substrate can in a known manner, for. Example by spraying, filling, doctoring, brushing, rolling, rolling, pouring, lamination, injection molding or coextrusion.

The coating thickness is generally in a range of about 3 to 1000 g / m ² and preferably 10 to 200 g / m ² . In addition, a process for coating substrates is disclosed, in which the coating composition according to the invention or a coating formulation containing it, optionally mixed with further coating-type additives and thermally, chemically or radiation-curable resins, is applied to the substrate and optionally dried with electron beams or UV exposure under oxygen-containing atmosphere or preferably under inert gas cures, optionally at temperatures up to the height of the drying temperature and then at temperatures up to 160 ° C, preferably between 60 and 160 ° C, more preferably between 100 and 160 ° C, thermally treated. The radiation curing is carried out with high-energy light, for example UV light or electron beams. The radiation curing can be carried out at higher temperatures. In this case, a temperature above the T _{g of} the radiation-curable binder is preferred. The coating compositions can be prepared by a variety of spraying methods, such as air pressure, airless or electrostatic spraying using single- or two-component spray systems, but also by spraying, filling, doctoring, brushing, rolling, rolling, casting, lamination, back molding or Coextrusion be applied once or several times. The drying and curing of the coatings is generally carried out under normal temperature conditions, ie without heating the coating. However, the mixtures according to the invention can also be used for the production of coatings which are dried and cured after application at elevated temperature, eg at 40-250 ° C., preferably 40-150 ° C. and in particular at 40-100 ° C. This is limited by the thermal stability of the substrate.

Furthermore, a process for coating substrates is disclosed, in which the inventive Beschichutngsmasse or coating formulations containing, optionally applied with thermally curable resins, applied to the substrate, dried, and then cured with electron beams or UV exposure under an oxygen-containing atmosphere or preferably under inert gas , optional at temperatures up to the height of the drying temperature.

The process for coating substrates can also be carried out so that after application of the coating composition or coating formulations according to the invention initially with electron beam or UV exposure under oxygen or preferably under inert gas is irradiated to obtain a pre-cure, then at temperatures up to 160 ° C, preferably between 60 and 160 ° C, thermally treated and then cured by electron beams or UV exposure under oxygen or preferably under inert gas. Optionally, if multiple layers of the coating composition are applied one above the other, drying and / or radiation curing may take place after each coating operation.

Suitable radiation sources for radiation curing are, for example, low-pressure mercury radiation lamps, medium-pressure lamps with high-pressure lamps and fluorescent tubes, pulse emitters, metal halide lamps, electronic flash devices, whereby radiation curing without photoinitiator is possible, or excimer radiators. The radiation is cured by exposure to high-energy radiation, ie UV radiation or daylight, preferably light in the wavelength range of λ = 200 to 700 nm, particularly preferably from λ = 200 to 500 nm and most preferably λ = 250 to 400 nm, or by Irradiation with high-energy electrons (electron radiation, 150 to 300 keV). High-pressure mercury-vapor lamps, lasers, pulsed lamps (flashlight), LED lamps, halogen lamps are used as radiation sources. pen or excimer radiator. The radiation dose for UV curing, which is usually sufficient for crosslinking, is in the range from 80 to 3000 mJ / cm ² .

Of course, several radiation sources can be used for the curing, e.g. two to four.

These can also radiate in different wavelength ranges.

The drying and / or thermal treatment can also be carried out in addition to or instead of the thermal treatment by NIR radiation, wherein NIR radiation here electromagnetic radiation in the wavelength range of 760 nm to 2.5 μηη, preferably from 900 to 1500 nm is designated.

The irradiation can optionally also in the absence of oxygen, for. B. under inert gas atmosphere, carried out. As inert gases are preferably nitrogen, noble gases, carbon dioxide, or combustion gases. Furthermore, the irradiation can be carried out by covering the coating mass with transparent media. Transparent media are z. As plastic films, glass or liquids, eg. B. water. Particular preference is given to irradiation in the manner as described in US Pat

DE-A1 199 57 900 is described.

Ppm and percentages used in this specification, unless otherwise indicated, are by weight percent and ppm. The following examples are intended to illustrate but not to limit the invention.

Examples Example 1:

Production of a thiol dispersion according to the invention

In a stirred tank, 33.3 parts of isophorone diisocyanate, 13.4 parts of dimethylolpropionic acid, 30 parts of acetone and 0.5 part of dibutyltin dilaurate were mixed at room temperature and then heated to reflux. The dimethylolpropionic acid slowly dissolved and the batch became highly viscous after about 3 hours. After a reaction time of 4 hours, it was cooled to room temperature and 48.8 parts of pentaerythritol tetrakis (3-mercaptopropionate) and 20 parts of acetone were added. Thereafter, it was left to react for 4 hours at 60 ° C. The NCO value dropped to 0.

At 50 ° C, the reaction mixture was neutralized with 10 parts of triethylamine and within 30 minutes 140 parts of water were added. Thereafter, the acetone was removed in vacuo. distilled. The dispersion had a solids content of 48% and the particle size of the translucent dispersion was less than 20 nm.

Example 2:

Production of a thiol dispersion according to the invention

In a stirred tank, 33.3 parts of isophorone diisocyanate, 6.7 parts of dimethylolpropionic acid, 7.2 parts of cyclohexanedimethanol, 30 parts of acetone and 0.5 part of dibutyltin dilaurate were mixed at room temperature and then heated to reflux. The dimethylolpropionic acid slowly dissolved and the batch became highly viscous after about 3 hours. After a reaction time of 4 hours, it was cooled to room temperature and 48.8 parts of pentaerythritol tetrakis (3-mercaptopropionate) and 20 parts of acetone were added.

 Thereafter, it was left to react for 4 hours at 60 ° C. The NCO value dropped to 0. At 50 ° C, the reaction mixture was neutralized with 5 parts of triethylamine and within 30 minutes 190 parts of water were added. Thereafter, the acetone was distilled off in vacuo.

 The dispersion had a solids content of 41% and the particle size of the translucent dispersion was less than 20 nm.

Example 3:

Mixtures were prepared from the parts given in the table of a radiation-curable, commercially available dispersion (Laromer® UA 9064, BASF SE, water-based dispersion of a urethane acrylate, solids content about 38% by weight, average particle size <150 nm), the parts indicated of the thiol dispersion of Example 1 and in each case 2 parts, based on the solid, of the photoinitiator Irgacure® 500:

Application testing

The dispersions 3a to 3e are coated with a box doctor blade of 250 μηη slit width per 3 glass plates per series.

One glass plate was dried for 30 minutes at room temperature and then for 20 minutes at 60 ° C in a drying oven. Then in an IST exposure system with 1350 mJ / cm ² was exposed under air atmosphere. One glass plate was dried for 30 minutes at room temperature and then for 20 minutes at 60 ° C in a drying oven. After that was in an IST exposure system with

1350 mJ / cm ² exposed under nitrogen atmosphere.

One glass plate each was stored at room temperature.

After exposure or after storage (1 day, 2 days, 5 days), the hardness was measured in seconds using the pendulum hardness according to King DIN 53157. High values mean high hardness.

The results show that the dispersions based on the combination of UV-curable dispersions and thiol-terminated dispersions are almost not inhibited by oxygen in UV exposure and exhibit a slight increase in pendulum hardness, and especially when stored at room temperature, a significant increase in pendulum hardness with storage time demonstrate. The pure mixtures of the dispersions 3b-3d are still stable after 5 days of storage. Comparative Example 1

A mixture of 10 parts of Laromer UA 9064 and 10 parts of the water-soluble triple 3-mercaptopropionic acid ester of ethoxylated trimethylolpropane of molecular weight 1300 (Bruno Bock GmbH) was prepared. Already without the addition of photoinitiator, the mixture gelled after 2 hours.

Claims

claims

1 . Containing aqueous dispersions

 at least one water-dispersible radiation-curable polyurethane (A) containing as structural components

 (Aa) at least one organic aliphatic, aromatic or cycloaliphatic

Di- or polyisocyanate

 (Ab) at least one compound having at least one isocyanate-reactive

Group and at least one free-radically polymerizable unsaturated group, (Ac) optionally at least one compound having at least two isocyanate-reactive groups,

 (Ae) optionally at least one compound with exactly one isocyanate-reactive group,

 (Ag) at least one compound having at least one isocyanate-reactive group and at least one dispersive-active group,

 and at least one water-dispersible compound (B) having at least two mercapto groups.

2. Aqueous dispersions according to claim 1, characterized in that the component (Aa) are monomers or oligomers of aliphatic or cycloaliphatic diisocyanates.

3. Aqueous dispersions according to claim 1 or 2, characterized in that the

 Component (Ag) as dispersing groups anionic or into an anionic group convertible groups.

4. Aqueous dispersions according to one of the preceding claims, characterized in that the mercapto groups are -SH groups which are bonded to methylene groups.

5. Aqueous dispersions according to one of the preceding claims, characterized in that the compounds (B) have a number average molecular weight M _n of at least 750 g / mol.

6. Aqueous dispersions according to one of the preceding claims, characterized in that it is the compound (B) is a water-dispersible and mercapto to-containing polyurethane, composed of the components

(Ba) at least one organic aliphatic or cycloaliphatic di- or polyisocyanate, (Bc) optionally at least one compound having at least two isocyanate-reactive groups,

 (Bg) at least one compound which has at least one isocyanate-reactive group and at least one dispersive-active group,

 (Be) optionally at least one compound with exactly one isocyanate-reactive group and

 (Bf) at least one compound having at least two mercapto groups.

Aqueous dispersions according to claim 6, characterized in that compound (Ba) is selected from the group consisting of hexamethylene diisocyanate, 1, 3-bis (isocyanate-ethyl) cyclohexane, isophorone diisocyanate, 4,4'- and 2,4'-bis Di (isocyanatocyclohexyl) methane.

Aqueous dispersions according to one of Claims 6 or 7, characterized in that compound (Bf) is reaction products of alcohols with 2-mercaptoacetic acid or 3-mercaptopropionic acid or derivatives thereof.

Aqueous dispersions according to any one of claims 6 to 8, characterized in that compound (Bf) has the formula

having,

wherein

R ¹ , R ^{2 are} each independently hydrogen or a C ¹ to C ⁴ alkyl radical,

R ^{4 is} methylene or 1, 2-ethylene, k, I, m, q, each independently zero or a positive integer from 1 to 5, preferably zero or a positive integer from 1 to 4 and particularly preferably zero or a positive integer from 1 to 3, each Yi for i = 1 to k, 1 to I, 1 to m and 1 to q, independently of one another, may be selected from the group consisting of -CH 2 -CH 2 -O-, - CH2-CH (CH3) -0-,

-CH (CH ₃ ) -CH ₂ -O-, -CH ₂ -C (CH ₃ ) ₂ -O-, -C (CH ₃ ) ₂ -CH ₂ -O-, -CH ₂ -CHVin-O-, -CHVin-CH ₂ -0-,

-CH ₂ -CHPh-O- and -CHPh-CH ₂ -O-, preferably from the group -CH ₂ -CH ₂ -0-,

-CH ₂ -CH (CH ₃ ) -O- and -CH (CH ₃ ) -CH ₂ -O-, and more preferably -CH ₂ -CH ₂ -O- wherein Ph is phenyl and Vin is vinyl.

Process for preparing aqueous dispersions according to one of the preceding claims, characterized in that polyurethanes (A) and (B) are prepared separately from one another as aqueous dispersions and then these aqueous dispersions are mixed together.

Use of aqueous dispersions according to any one of claims 1 to 9 for the coating of wood, wood veneer, paper, cardboard, textile, leather, fleece, plastic surfaces, glass, ceramics, mineral building materials, metals or coated metals.