WO2010118836A2 - Polyurethane dispersions for organic passivation - Google Patents

Abstract

The invention relates to novel aqueous polyurethane dispersions for coating and painting metal substrates, in particular organically passivating metal substrates inhibiting the same against corrosion, and to the production of said dispersions.

Description

 Polyurethane dispersions for organic passivation

The invention relates to novel aqueous polyurethane dispersions for the coating and coating of metallic substrates, in particular the organic passivation of metallic substrates and their inhibition against corrosion and the preparation of these dispersions.

Metallic substrates, in particular strip steel and sheets, are frequently protected against corrosion by chromating. For many applications, alternative methods of chromatization are sought to avoid the use of questionable chromium (VI) compounds. Polyurethane dispersions for the passivation of metals are known in principle. Such dispersions are e.g. in JP 2007044973, JP 20055206764, JP 2004018887 or EP 1186351. However, all these dispersions still have considerable disadvantages.

The dispersions according to JP 2007044973 have e.g. relatively low solids contents, contain high levels of hydrophilic groups and neutralization amines and are not thermally, discoloration and Kreidungsstabil due to the polyethers and aromatic isocyanate structures contained.

The dispersions according to JP 20055206764 contain aliphatic polyester segments and are therefore potentially susceptible to hydrolysis. In addition, very high amounts of organic solvents are included, which is ecologically disadvantageous. The incorporated aromatic polyether structures give disadvantages with regard to discoloration and chalking stability.

Cationic dispersions, e.g. in JP 2004018887, often have the disadvantage that the solids contents are rather low, the polyether constituents, the aromatic cyanate building blocks and the quaternary ammonium salts lead to discoloration and fading. In addition, the cationic dispersions must be kept strictly separate from the dominant and usually preferred anionic dispersions, since these two types of dispersion are absolutely incompatible with each other.

EP 1186351 describes polyurethane dispersions having very high contents of hydrophilic salt groups, which lead to the coatings being able to be washed off again by aqueous, alkaline solutions. Thus, u.a. the stability of these dispersions or the corresponding coatings, e.g. insufficient against alkalis.

It was therefore an object of the present invention to provide anionically hydrophilicized polyurethane dispersions which meet the requirements for organic passivation of metallic substrates. These are essentially very good ones Corrosion protection and alkali resistance, excellent thermal stability, discoloration stability and resistance to chalking, stability against fading, as well as deformability and stacking resistance. In addition, the dispersions should have the highest possible solids contents, contain as few hydrophilic groups as possible and have as few volatile organic substances, in particular solvents and neutralizing agents. Furthermore, the dispersions should be as finely divided as possible in order to enable very good film formation even with thin layers, as well as course and adhesion.

Surprisingly, it has been found that special polyurethane dispersions are excellently suited to meet all the requirements of organic passivation. Coatings produced on the basis of the polyurethane dispersions according to the invention have low contents of volatile organic components, exhibit rapid drying, very good film formation, very good corrosion protection properties and alkali resistance, excellent thermal stability, stability against fading and stacking resistance, and extremely low weight losses after cleaning alkaline or acidic cleaning or degreasing media, such as Gardoclean® products (Chemetall GmbH, Frankfurt, Germany)

The following percentages of the individual components always add up to 100% by weight.

The invention relates to polyurethane dispersions containing reaction products of the following components:

a) from 20 to 45% by weight of at least one, at least difunctional, aliphatic polyisocyanate component consisting of at least 75% of isophorone diisocyanate,

b) 30 to 65 wt .-% of at least one polyol component having a number average molecular weight (M _n ) of 800 to 6000 g / mol, consisting of at least 50% of at least one aliphatic polycarbonate polyol and / or an aromatic

Polyester polyol based on isophthalic acid, terephthalic acid and / or phthalic anhydride,

c) from 1.5 to 8% by weight of at least one hydrophilizing component which, in addition to at least one hydrophilic group, has one or two amino or hydroxyl groups,

d) from 1 to 15% by weight of at least one low molecular weight diol i and / or triol component,

e) 0.3 to 8 wt .-% of at least one amino group and / or an amino and

Hydroxyl-containing chain extender component ₂ and f) 0 to 15 wt .-% of a monofunctional hydrophobizing component.

Preferred subject of the invention are polyurethane dispersions containing reaction products of the following components:

a) from 20 to 45% by weight of at least one, at least difunctional, aliphatic polyisocyanate component consisting of at least 90% of isophorone diisocyanate,

b) 30 to 65 wt .-% of at least one polyol component having a number average molecular weight (M _n ) of 800 to 4000 g / mol, consisting of at least 75% of at least one aliphatic polycarbonate polyol and / or an aromatic polyester polyol based on isophthalic acid, terephthalic acid and / or phthalic anhydride,

c) 1.5 to 5.5 wt .-% of at least one hydrophilicizing component with

Carboxylic acid groups having at least one hydrophilic acid group one or two amino or hydroxyl groups,

d) from 1 to 12% by weight of at least one low molecular weight diol and / or triol component,

e) from 0.5 to 6% by weight of at least one amino-group-containing and / or amino- and hydroxyl-containing chain-lengthening component,

f) 0 to 8 wt .-% of a monofunctional hydrophobizing component.

For the polyisocyanate component a) suitable, at least difunctional polyisocyanates are e.g. 1, 3-cyclohexane diisocyanate, 1-methyl-2,4-diisocyanato-cyclohexane, 1-methyl-2,6-diisocyanato-cyclohexane, tetramethylene diisocyanate, 4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyanatodiphenylmethane, 2, 4-diisocyanatotoluene, 2,6-diisocyanatotoluene, α, α, α, 'α,' - tetra-methyl-m- or p-xylylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, 1,6-hexamethylene diisocyanate, 1-isocyanato-3,3 , 5-trimethyl-5-isocyanatomethyl-cyclohexane

(Isophorone diisocyanate), hexahydro-2,4- or 2,6-diisocyanatotoluene and 4,4'-

Diisocyanatodicyclohexylmethan, and mixtures thereof, optionally with other isocyanates, wherein aliphatic Polyisoacyanate are preferred and aromatic isocyanates only in minor amounts of <5 wt.%, Based on the total amount of polyisocyanates a), be used.

It is also possible to use higher-functional homologs, oligomers or prepolymers of the at least difunctional polyisocyanates mentioned by way of example which, for example, urethane, Biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione, uretdione, amide, imide, ether, carbonate and / or ester groups.

In minor amounts of <5% by weight, based on the total amount of polyisocyanates a), monofunctional polyisocyanates may also be used, e.g. Stearyl isocyanate, butyl isocyanate, phenyl isocyanate.

The polyisocyanate component a) preferably comprises at least 75% by weight of isophorone diisocyanate.

Particularly preferably, the polyisocyanate component a) comprises at least 90% by weight of isophorone diisocyanate.

Surprisingly, it has been found that when using larger amounts of e.g. 4,4'-diisocyanatodicyclohexylmethane deteriorates the thermostability of the coatings and also the resistance to alkaline detergents. Therefore, 4,4'-diisocyanatodicyclohexylmethane should only be used in minor amounts of less than 25% by weight, preferably less than 10% by weight, based on the total amount of polyisocyanates a). It is particularly preferable to dispense with the use of 4,4'-diisocyanatodicyclohexylmethane and to use isophorone diisocyanate.

This result is surprising and unexpected since polyurethane dispersions based on 4,4'-diisocyanatodicyclohexylmethane are generally regarded as particularly high-quality dispersions.

When aromatic polyisocyanates are used in component a), the adverse effects are expected to be even more pronounced. Therefore, the use of aromatic polyisocyanates in component a) only in minor amounts of <5 wt.% Based on the total amount of polyisocyanates a) is possible and generally less preferred. Preferably, the use of aromatic polyisocyanates in component a) is dispensed with.

Suitable components b) are, for example, basically polyester polyols, polycarbonate polyols, C3 and / or C4 polyether polyols, polyamide polyols, polyimide polyols, polymer polyols, polyurethane polyols, polyurethane thiols, polyurethane amines, polyurea diols, polyureas, polyureas, polyester amines, polyether amines, polycarbonate amines, polyamidoamines, polyimideamines, mixtures , Combinations and block copolymers of said and / or other raw materials. The average functionalities of the polyols are 1.5 to 4, preferably 2 to 3 and particularly preferably 2.

The number-average molecular weights (M _n ) of component b) are from 600 to 10,000, preferably from 800 to 6000 and more preferably from 800 to 4000 g / mol.

Preferred components b) are aromatic polyester polyols and / or aliphatic polycarbonate polyols, optionally in combination with minor amounts of aliphatic polyester polyols and / or C4 polyether polyols.

Suitable raw materials for the preparation of the aromatic polyester polyols are, for. B. bl) aliphatic dicarboxylic acids or their anhydrides such as adipic acid, azelaic acid, sebacic acid, glutaric acid, fumaric acid, maleic anhydride, dimer fatty acids, aromatic Dioder tricarboxylic acids, or their anhydrides such as phthalic anhydride, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, trimellitic anhydride and pyromellitic anhydride, and cycloaliphatic di- , and tricarboxylic acids and their anhydrides such as Hexahydrophthalic anhydride, tetrahydrophthalic anhydride and / or cyclohexanedicarboxylic acid,

b2) diols, triols and / or tetraols, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, butenediol, butynediol, 1, 6- hexanediol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, 2,2-dimethyl-3-hydroxypropionic acid (2,2-dimethyl-3-hydroxypropyl ester), diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, tetraethylene glycol, positionally isomeric diethyloctanediols , hydrogenated bisphenols, hydrogenated and ethoxylated bisphenols, ethoxylated pyrocatechol, ethoxylated resorcinol, ethoxylated hydroquinone, ethoxylated and alkyl-substituted hydroquinones, resorcinols and pyrocatechols, 2-methyl-1,3-propanediol, 3-methyl-l, 5-pentanediol, trimethylpentanediol, 1 , 8-octanediol, tricyclodecanedimethanol, castor oil, trimethylolpropane, glycerol, propoxylated or ethoxylated trimethylolpropane or glycerol, pentaerythritol and mixtures of the abovementioned and optionally other diols, triols and / or tetraols,

b3) other polyester raw materials such as e-caprolactone, monoepoxides such as the glycidyl ester of versatic acid, bisepoxides such as epoxidized bisphenols, polyepoxides, epoxidized fatty acids or oils, butylglycol, butanol, pentanol, 2-ethylhexanoic acid, tert-butylbenzoic acid, benzoic acid, soybean oil fatty acid , Oleic acid, stearic acid, C8 to C30 monocarboxylic acids or mixtures thereof. It is also possible to use amino- and / or thio-functional components as a component b3) with, for example, isophoronediamine, hexamethylenediamine, ethylenediamine, butylamine, diethanolamine, diisopropanolamine, diphenylmethylenediamine (MDA).

The aromatic polyester polyols b) preferably contain the following raw materials:

bl) phthalic anhydride, isophthalic acid and / or terephthalic acid, if appropriate in combination with adipic acid, maleic anhydride, dimer fatty acids, hexahydrophthalic anhydride, tetrahydrophthalic anhydride and / or cyclohexanedicarboxylic acid,

b2) ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, 2,2-dimethyl-3- hydroxypropionic acid (2,2-dimethyl-3-hydroxypropyl ester), diethylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 3-methyl-l, 5-pentanediol, castor oil, trimethylopropane, glycerol and / or pentaerythritol,

b3) e-caprolactone, monoepoxides, e.g. the glycidyl ester of the Versatiesäure, 2-ethylhexanoic acid, tert-butylbenzoic acid, benzoic acid, stearic acid and / or saturated C8 to C30 monocarboxylic acids or mixtures thereof.

Particularly preferred components b) are aromatic polyesters having a hydroxyl number of 10 to 230, preferably from 48 to 160 mg KOH / g substance, the reaction products are from

bl) 38 to 72, preferably 52 to 72,% by weight of at least one aromatic di- and / or tricarboxylic acid or its anhydride, in particular terephthalic acid, isophthalic acid and / or phthalic anhydride,

b2) from 20 to 55, preferably from 25 to 50,% by weight of at least one diol and / or triol, and / or tetraols,

b3) from 0 to 40, preferably from 0 to 25,% by weight of further components, e.g. monofunctional alcohols, monocarboxylic acids, monoepoxides, bisepoxides, polyepoxides and lactones.

The acid number of the corresponding polyesters in component b) is usually from 10 to 0.1 mg KOH / g, preferably from 5 to 1 mg KOH / g.

Particularly preferred polyols as component b) are likewise aliphatic polycarbonate diols based on diols, diol mixtures and / or difunctional oligomers or polymers based on ethers and / or esters, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1 , 4-butanediol, 1, 6-hexanediol, 1, 4-cyclohexanedimethanol, 1, 4-cyclohexanediol, 2,2-dimethyl-3 hydroxypropionic acid (2,2-dimethyl-3-hydroxypropyl ester), diethylene glycol, dipropylene glycol, hydrogenated bisphenols, hydrogenated and ethoxylated bisphenols, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, TCD- Diol, difunctional C3 and / or C4 ethers having number average molecular weights (M _n ) to 1000 g / mol.

Particularly preferred aliphatic polycarbonate polyols are polycarbonate polyols based on neopentyl glycol, 1, 6-hexanediol, 1, 4-butanediol, 1,4-cyclohexanedimethanol, 1, 4-cyclohexanediol, 3-methyl-l, 5-pentanediol, TCD-diol and their Mixtures with a functionality of 1.9 to 2.1.

Also particularly preferred is the use of two different polyol components, in particular the combination of aliphatic polycarbonate diol with aromatic polyester diol or the combination of aliphatic polycarbonate diol with aromatic and aliphatic polyester diols.

The polyol component b) consists of 50%, preferably 75% and particularly preferably 100% of at least one aliphatic polycarbonate diol and / or an aromatic polyester diol based on isophthalic acid, terephthalic acid and / or phthalic anhydride.

Suitable hydrophilizing components c) are compounds having at least one isocyanate-reactive group, e.g. primary and / or secondary amino groups and / or hydroxyl groups and at least one carboxyl group and / or their salts formed by addition of neutralizing agents.

Hydrophilic components c) are usually present in amounts of from 1 to 8,% by weight, preferably in amounts of from 1.5 to 7, and more preferably in amounts of from 1.5 to 5.5% by weight.

Suitable hydrophilizing components c) are, for example, mono- and dihydroxycarboxylic acids, mono- and diaminocarboxylic acids, mono- and dihydroxysulfonic acids, mono- and diaminosulfonic acids, and mono- and dihydroxyphosphonic acids or mono- and diaminophosphonic acids and their salts, such as dimethylolpropionic acid, dimethylolbutyric acid, dimethylolacetic acid, 2,2- Dimethylolpentanoic acid, dihydroxysuccinic acid hydroxypivalic acid, N- (2-aminoethyl) alanine, 2- (2-aminoethylamino) ethanesulfonic acid, ethylenediaminepropyl- or butylsulfonic acid, 1,2- or 1,3-propylenediamine-ethylsulfonic acid, malic acid, citric acid, glycolic acid , Lactic acid, glycine, alanine, taurine, lysine, 3,5-diaminobenzoic acid, 6-aminohexanoic acid, 11-aminoundecanoic acid, aminoacetic acid, an addition product of IPDA, hexamethylenediamine or other diamines and acrylic acid (EP-A 0 916 647, Example 1) and its Alkali and / or ammonium salts; the Adduct of Natriumbisulfϊt of butene-2-diol-l, 4, polyethersulfonate, the propoxylated adduct of 2-butenediol and NaHSO ₃ , for example described in DE-A 2 446 440 (page 5-9, formula Im) or the salts the described anionic hydrophilicizing agents, as well as mixtures of said anionic and optionally other anionic hydrophilicizing agents, optionally together with nonionic hydrophilicizing agents.

It is also possible to use nonionic hydrophilicizing components proportionately in amounts of less than 5% by weight, based on the solids of the dispersion. This can e.g. its amino- and / or hydroxyl-containing, mono- and / or di- and / or trifunctional ethylene oxide polyether, propylene oxide / ethylene oxide copolyether or

Propylene oxide / ethylene oxide block polyethers of the number average molecular weight range (M _n ) 200 to 3000 g / mol.

Preferred nonionic compounds are monohydroxy-functional

Polyalkylene oxide polyethers which have at least 75 mol% of ethylene oxide, particularly preferably 100 mol%, of ethylene oxide units and have a number average molecular weight (M _n ) of from 350 to 2500, particularly preferably from 500 to 1100 g / mol.

If nonionic hydrophilicizing components are used, this is done in combination with ionic hydrophilicizing agents, monohydroxy-functional nonionic hydrophilicizing agents being preferred.

Particularly preferred polyurethane dispersions according to the invention contain no nonionic hydrophilicizing components.

Particularly preferred hydrophilizing components c) are dimethylolpropionic acid, dimethylolbutyric acid, hydroxypivalic acid, 6-aminohexanoic acid, and addition products of IPDA, hexamethylenediamine or other diamines with acrylic acid.

The acid number of the aqueous polyurethane dispersions according to the invention is between 5 and 30 mg KOH / g substance, preferably between 10 and 25 and more preferably between 13 and 21 mg KOH / g substance.

Surprisingly, it is possible by suitable choice of raw materials and a suitable

Production process even with the relatively low acid numbers of the particularly preferred range of 13 to 21 mg KOH / g substance to obtain finely divided dispersions having optimum film formation and course, all requirements, for example, with respect to corrosion protection, alkali resistance, Remaining agent stability and Thermostabihtät excellent and have few hydrophilic groups as potential weak points of a coating

The free acid groups represent "potentially ionic" groups, while the salt-like groups, carboxylate groups, obtained by neutralization with neutralizing agents are ionic groups

The ionic hydrophiherendenenden components c) before or during the Dispersierschπtt by reaction with a neutralizing agent proportionately or completely converted into the corresponding salt. This is possible in principle before or during the individual process steps in the production processes described below.

The degree of neutralization is usually between 40 and 150%, preferably 60 to 120%, whereby the degree of neutralization is to be understood as meaning the theoretical percentage of salt groups in the total amount of hydrophilic and potentially hydrophilic groups.

Suitable neutralizing agents which are suitable for the neutralization or salt formation of acid groups and may already be present during the reaction of components a) to f) are, for example, trimethylamine, ethyldnsopropylamine, dimethylisopropylamine, dimethylcyclohexylamine, N-methylmorpholine and mixtures thereof. Also suitable are e.g. Ammonia, dimethylethanolamine, methyldiethanolamine, ammomethylpropanol, diethanolamine, ethanolamine, Dnsopropanolamin, N-methyldnsopropanolamine, Tπethanolamm, dibutylamine, diethylamine, Dimethyhsopropanolamin and mixtures of said neutralizing agent Preferably, the latter neutralizing agent are added after the reaction of components a) to f).

Preferred neutralizing agents are trimethylamine, Ethyldπsopropylamm,

Dimethylisopropylamine, dimethylcyclohexylamine, N-methylmorpholine, N-ethylmorpholm and dimethylethanolamine

Suitable components d) are low molecular weight diols and / or toluenes such as e.g. Ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,5-pentanediol, hydrogenated bisphenol A, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, Neopentyl glycol, hydroxypic acid neopentyl glycol ester, trimethylolpropane, trimethylolethane, glycine, trimethylolbenzene, TCD-diol and / or trihydroxyethyl isocyanurate.

Also suitable components d) are reaction products of the exemplified diols or Tnole d) with 0.2 to 3 equivalents of epsilon-caprolactone. Preferred components d) are ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and / or hydrogenated bisphenol A.

Components d) are used in amounts of from 1 to 15, particularly preferably from 1 to 12,% by weight.

Suitable chain-extending components e) containing amino groups and / or amino and hydroxyl groups are di- and / or triamines, such as, for example, ethylenediamine, propylenediamine, 1,2-diaminopropane, 1,4-diaminobutane, 2,5-diamino-2 , 5-dimethylhexane, 1,5-diamino-2-methylpentane, 1,6-diaminohexane, 2,2,4- and / or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, triaminononane, hydrazine, hydrazine hydrate, adipic dihydrazide, diethylenetriamine, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (IPDA), 2,4- and / or 2,6-hexahydro-toluylenediamine ( H ₆ TDA), isopropyl-2,4-diaminocyclohexane and / or isopropyl-2,6-diaminocyclohexane, 1,3-bis (aminomethyl) -cyclohexane, 2,4'- and / or 4,4'-diamino dicyclohexylmethane, 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane (Laromin C 260 ^®, BASF AG, DE), the isomeric, a methyl group as ring substituent having diaminodicyclohexylmethanes (= C-monomethyl-diaminodicyclohexyl methanes), 3 (4 ) - Aminomethyl-1-methylcyclohexylamine (AMCA) and araliphatic diamines such as 1,3-bis (aminomethyl) benzene, xylylenediamine. Amino alcohols are also suitable components e), for example 2-aminoethanol, aminopropanols, diethanolamine, diisopropanolamine, N-methylethanolamine, 3-amino-1,2-propanediol, aminobutanols, 1,3-diamino-2-propanol, bis (2-aminoethanol). hydroxypropyl) amine, propanolamine I, r-dimethyl-1, 1'-dipropyl-2,2'iminodiethanol, 2- (2-hydroxyethyl) amino-2-methylpropan-1-ol, 1- (2-hydroxyethyl -) - amino-2-propanol, 3,3'-diallyloxy-2,2'-dihydroxy-dipropylamine, hydroxyethylethylenediamine and

Bis (hydroxyethyl) ethylene diamine. Preferred amino alcohols contain at least 2 amino groups.

Also suitable are Michael adducts, e.g. obtained by reaction of bifunctional, primary amines with maleic acid diesters and are referred to as aspartic acid esters. Such aspartic acid esters are described, for example, in EP-A 403 921.

Also suitable are mixtures of said components e) of all kinds, if appropriate also with further components.

Preferred components e) are isophoronediamine, diethylenetriamine, ethylenediamine and / or hydrazine hydrate. Particularly preferred is the combination of isophoronediamine, diethylenetriamine and hydrazine hydrate or ethylenediamine as component e). Component e) consists preferably of 50 to 90% isophoronediamine, 3 to 25% of diethylenetriamine and 5 to 35% of hydrazine hydrate or ethylenediamine. Component e) is particularly preferably composed of 60 to 85% isophoronediamine, 5 to 20% of diethylenetriamine and 8 to 25% of hydrazine hydrate or ethylenediamine.

Surprisingly, this particular combination of three different chain extension reagents adds significantly to the excellent level of properties.

Possible hydrophobizing component f) are monofunctional, i. isocyanate-reactive, hydroxyl and / or amino-containing compounds having one or more, linear and / or branched, saturated and / or unsaturated C6 to C30, preferably C8 to C22 and particularly preferably C 12 to C 20 hydrocarbon chains and / or or hydroxy- or amino-functional aromatic, optionally substituted hydrocarbon rings containing compounds.

Suitable hydrophobizing compounds f) are e.g. 1-hexanol, 2-ethyl-1-butanol, 2-ethylhexanol, 1-octanol, 2-octanol, 3-octanol, 1-nonanol, 2-nonanol, 2,4,4-trimethyl-1-hexanol, 3, 5,5-trimethyl-1-hexanol, 1-decanol, 2-decanol, 3-decanol, 4-decanol, 1-dodecanol, 1-tetradecanol, 1-hexanecanol, 1-heptadecanol, stearyl alcohol, eicosanol, behenyl alcohol, cetyl alcohol, Lauryl alcohol, myristyl alcohol, oleyl alcohol, capryl alcohol, decyl alcohol, 1-octadecanol, benzyl alcohol, tert-butylbenzyl alcohol, 2-phenoxyethanol, cinnamyl alcohol, 1-phenoxy-2-propanol, 2-hexyldecan-1-ol, Guerbet alcohols, saturated and / or or unsaturated C6-C30 fatty alcohols and fatty alcohol mixtures of all kinds, terpene alcohols, monoesters of diols with C6-C30 fatty acids, monoesters of triols with C6-C30 fatty acids such as Glycerol distearate, glycerol dioleate, glycerol diocetylate, transesterification products of castor oil and other oils or fats, e.g. Peanut oil or coconut oil, dodecanamine, tetradecanamine, hexadecanamine, octadecanamine, N-methyl-1-octadecanamine, cocoamine, laurylamine, stearylamine, C16-C22 alkylamine and / or oleylamine and / or mixtures of the exemplified and optionally other corresponding compounds.

Preferred hydrophobicizing components f) are monofunctional, linear and / or branched and / or unsaturated C 8 -C 22 alcohols and / or amines, for example stearyl alcohol, cetyl alcohol, lauryl alcohol, oleyl alcohol, myristyl alcohol, C 8 -C 22 fatty alcohols or Fatty alcohol mixtures, the corresponding alcohols such amino compounds such as stearylamine, laurylamine, cetylamine, fatty amines, etc., or mixtures of the above components.

The component f) is used in amounts of 0 to 15, preferably from 0 to 10 and particularly preferably in amounts of 0 to 8 wt .-%.

In a preferred embodiment, the polyurethane dispersions according to the invention comprise reaction products of the following components:

a) from 20 to 45% by weight of at least one, at least difunctional, aliphatic polyisocyanate component consisting of at least 90% of isophorone isocyanate,

b) 30 to 65 wt .-% of at least one polyol component having a molecular weight of

800 to 4000 g / mol, consisting of 100% of at least one aliphatic polycarbonate polyol based on hexanediol and / or an aromatic polyester polyol based on isophthalic acid, terephthalic acid and / or phthalic anhydride,

c) 1.5 to 5.5% by weight of dimethylolpropionic acid

d) 1 to 12% by weight of 1,4-cyclohexanedimethanol and / or butanediol and / or neopentyl glycol,

e) 0.5 to 6% by weight of a chain extender component containing isophorone diamine and ethylene diamine and / or hydrazine hydrate and diethylene tnamine,

f) 0 to 8% by weight of a monofunctional, hydrophobing component.

The pH values of the polyurethane dispersions according to the invention are between 5 and 12, preferably between 6 and 9.

The present invention likewise provides a process for the preparation of the polyurethane dispersions according to the invention, which comprises the components a) to d) and optionally f), if appropriate in the presence of catalytically active substances and / or neutralizing agents, in one or more successive The following reaction steps are reacted together to form an isocyanate-functional prepolymer, wherein the ratio of NCO groups to OH, NH 2, NH groups is 2.2 to 1.2 to 1, preferably 1.85 to 1.25 to 1 , wherein solvent and / or neutralizing agent are added before, during and / or after the reaction, wherein after reaction of components a) to d) and optionally f) either a chain extension with component e) in organic solution followed by dispersing in or with water, or with chain extension with component e) in aqueous dispersion, and with the solvent being separated off by distillation or completely or proportionally during or after the dispersing step.

A preferred preparation process is a two-stage preparation process of the isocyanate-functional prepolymer in at least one non-isocyanate-reactive solvent, the components a), b), c) and optionally f) optionally being reacted in the presence of catalytically active substances in the first reaction step until the theoretical NCO- Content is reached or slightly below and in a second reaction step, the component d) is added and reacted until the isocyanate-functional prepolymer has reached or fallen below the theoretical isocyanate value, wherein then, optionally after further dilution with solvent, a chain extension reaction with component e ) is carried out at 30 to 55 ° C in the organic phase and is then dispersed by adding water or by dispersing in the initial charge of water, wherein before or during the dispersion, a sufficient amount of neutralizing agent has been added, and wherein or distilled off after distilling the distillatively removable solvent with boiling points at atmospheric pressure of below 100 ° C at least 99%.

The chain extension reaction with component e) is carried out in such a way that a degree of chain extension (defined as the amount of NCO-reactive groups in e) to remaining NCO groups in the prepolymer from a) to d) and optionally f)) is from 30 to 120% by weight. -%, preferably from 50 to 85% is selected.

The preparation of the polyurethane dispersions according to the invention is carried out in organic solution, preferably with solids contents of from 30 to 95% by weight, preferably from 50 to 90% by weight.

Basically, all solvents are suitable which do not react with isocyanate groups and at least in admixture with other solvents have sufficient dissolving power for the raw materials or end products, such. Acetone, methyl ethyl ketone, methyl isobutyl ketone, solvent naphtha, toluene, xylene, cyclohexane, methoxypropyl acetate, N-methylpyrrolidone, N-ethylpyrrolidone, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether,

Ethylene glycol dimethyl ether or tetramethoxymethane.

A solvent mixture for the preparation of the inventive dispersion is particularly preferably used, consisting of acetone and a non-isocyanate-reactive solvents with a boiling point> 120 ⁰ C. Here, N-methylpyrrolidone and / or N-ethylpyrrolidone particularly preferred solvents. The proportions of the solvents are chosen so that the acetone is 90 to 98% of the total amount of solvent and the acetone is then completely distilled off again, while the higher-boiling solvent remains in the dispersion.

The resulting dispersions thus contain 0 to 6, preferably 1 to 4 wt .-% organic solvent, having a boiling point> 120 ⁰ C, preferably> 160 ⁰ C.

The reaction of components a) to d) and optionally f) can be carried out with or without the addition of catalytically active substances. Suitable catalysts are customary in polyurethane chemistry, metal catalysts, for example tin compounds such as dibutyltin dilaurate, Formrez ^® UL 29 (tin catalyst; Witco, USA), butyltin oxide, dibutyltin oxide, Fascat ^® 4100 (tin catalyst, Arkema, France), tin chloride, tin ü-octoate or Bismuth compounds such as bismuth octoate, mercury compounds such as phenylmercuric acetate, zinc compounds, also suitable are amine catalysts such as diazabicyclononene, diazabicyclooctane, diazabicycloundecene or dimethylaminopyridine. Suitable amounts of catalyst are, for example, 25 to 1000 ppm. It is also possible to use as a neutralizing agent, non-isocyanate-reactive amines, such as triethylamine or ethyldiisopropylamine as catalytically active substances in the reaction of a) to d) to use with. These neutralizing agents can be used in the amount that is necessary for salt formation with the acid groups for the desired hydrophilization.

In the preparation, after the preparation and in the application of the polyurethane dispersions according to the invention, it is also possible to use customary auxiliaries and additives, such as e.g. Anti-bacterial stabilizers, defoamers, acidic stabilizers such as dibutyl phosphate, stabilizers, antioxidants, thickeners, adhesion promoters, crosslinkers, light stabilizers, flow control agents, thermal stabilizers, anti-yellowing agents, wetting agents, emulsifiers, anti-settling agents, dispersing aids, foam stabilizers, anti-skinning agents, surface-active substances, etc.

The polyurethane dispersions according to the invention have solids contents of from 20 to 60, preferably from 30 to 50 and particularly preferably from 35 to 50% by weight, the average particle size of the dispersions is from 15 to 250, preferably from 20 to 120 nm and particularly preferably from 20 to 60 nm.

The polyurethane dispersions according to the invention can be used alone and also in combination with further polymers, dispersions or / and aqueous solutions, such as, for example, polyacrylate Dispersions, polyacrylate emulsions, alkyd dispersions, polyurethane-polyacrylate dispersions, styrene butadiene latexes, other polyurethane dispersions, polyester dispersions or solutions, aqueous or water-dilutable epoxy resins, epoxy resins, polyvinyl chloride dispersions, polyvinylidene chloride dispersions, polyvinylpyrrolidone dispersions, polyvinylimidazole dispersions, polyethylene dispersions, acrylonitrile (co) polymer dispersions, styrene (co) polymer dispersions, butadiene (co) polymer dispersions, vinylpyrrolidone (co) polymer dispersions, aqueous phenolic resins, aqueous condensation polymers, aqueous addition polymers, polymer dispersions, cellulose, Cellulose acetate and / or cellulose butyrate, dispersed, water-soluble or water-dispersible polyvinyl alcohols and / or optionally proportionally hydrolyzed polyvinyl esters and / or eg with silanol groups, alkoxysilane, acetoacetyl or other reactive groups modified polyvinyl alcohols bz polyvinyl esters, optionally modified or optionally proportionally hydrolyzed polyethylene vinyl ester copolymers or

Polyethylene vinyl alcohol copolymers, polyvinyl ether dispersions or solutions and / or in combination with low molecular weight, oligomeric and / or polymeric crosslinkers such. optionally polyisocyanates containing hydrophilic groups with free or blocked polyisocyanate groups, with polyaziridines, with polyepoxides, with polyalkoxysilanes, with carbodiimides, with polycarbodiimides, with polysiloxanes, with di- or polyhydrazides or amines, with carbonyl-containing polymers and / or crosslinkers and / or or with amino crosslinker resins, eg be used on melamine or urea-based.

The polyurethane dispersions according to the invention can be used in or as a lacquer, coating and / or size for coating optionally already precoated mineral or ceramic substrates and materials, concrete, asphalt, bitumen, hardboard materials, metallic substrates, plastics, paper, printing paper, Paperboard, composites, glass, porcelain, textile, leather, wood and woody substrates such as Furniture, fibreboard, parquet, window frames, doors, fences, panels, planks, beams, roofs, e.g. as a single-coat paint, in multi-coat paints, as a primer, as an intermediate, as a filler, as a basecoat, as a topcoat, as a barrier layer, as a primer, as a primer, in functional layers, as an overcoat, as a clearcoat, as a clearcoat, as a pigmented paint, in addition, in Adhesives, sealants, inks, inks, foams, films and fibers.

The curing can be carried out, for example, by physical drying at room temperature to 15O ⁰ C or / and by crosslinking reaction with corresponding crosslinkers at ambient temperature to 300 ⁰ C. Preferably, the dispersions of the invention are used for passivation and corrosion protection of metallic substrates and sheets. The metallic substrates include, for example, metal sheets, strip steel, metal strips, metal wires, metal rods, metal meshes, metal meshes, metal three-dimensional sheets, etc. based on a variety of steel alloys, iron, cast iron, aluminum, magnesium, titanium, galvanized materials.

Examples

Polyester b)

47849 isophthalic acid, 4784 g of terephthalic acid, 2274 g of ethylene glycol, 267 g of castor oil and 3460 g of neopentyl glycol are reacted by esterification at 230 ⁰ C to polyester b). Polyester b) has an acid number of 4 mg KOH / g substance and an OH number of 91 mg KOH / g substance.

Polyurethane dispersion 1)

In a 2 l reaction vessel with stirrer and reflux condenser, 5.6 g of butanediol, 24.5 g of dimethylolpropionic acid and 231 g of Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer MaterialScience AG, Germany) are weighed, diluted with 45.8 g of N-methylpyrrolidone and homogenized at 90 ⁰ C. 209.7 g of isophorone diisocyanate are then added and the reaction mixture is stirred at 90 ⁰ C until the NCO value is 9.7% with stirring. Then it is diluted with 304 g of acetone, 56 g of 1,4-cyclohexanedimethanol was added and stirred at 58 ⁰ C until an NCO value of 1.8% is reached. Then, a chain extending solution of 15.4 g of isophoronediamine and 2.8 g of diethylenetriamine, diluted with 25 g of acetone was added and stirred at 5O ⁰ C for 15 minutes. After addition of 16.7 g of triethylamine to neutralize the carboxyl groups is heated by the addition of 1050 g at 60 ⁰ C heated distilled water. After the distillative removal of the acetone, the polyurethane dispersion 1) according to the invention is obtained with a solids content of 35%, a viscosity of 27 mPas / 23 ° C., a pH of 8.3 and an average particle size of 100 nm.

Polyurethane dispersion 2)

In a 3 1 reaction vessel with stirrer and reflux condenser 98.7 g of polyester b), 38.6 g

Dimethylolpropionic acid, 259 g of Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer MaterialScience AG, Germany) and 24.6 g of stearyl alcohol were weighed, diluted with 67 g of N-methylpyrrolidone and at 90 ⁰ C. homogenized. 306.4 g Isophorondnsocyanat are then added and stirred the reaction mixture at 90 ⁰ C until the NCO value is 9.5% with stirring. Then it is diluted with 440 g of acetone and 70.9 g of 1, 4-cyclohexanedimethanol and stirred at 55 ⁰ C until an NCO value of 2.2% is reached. Then, a chain extension solution of 12.9 g of isophorone diamine, 3.4 g of hydrazine hydrate, 4 g Diethylentπamin diluted with 25 g of acetone was added and stirred at 50 ⁰ C for 90 minutes. After addition of 26.2 g Tπethylamin to neutralize the carboxyl groups is heated by adding 1140 g at 60 ⁰ C heated distilled water After distillative removal of the acetone obtained according to the invention polyurethane dispersion 2) having a solids content of 38%, a viscosity of 145 mPas / 23 ° C, a pH of 7.6 and a mean particle size of 33 nm.

Polyurethane dispersion 3)

107.7 g of polyester b), 38.9 g of dimethylolpropionic acid and 273.6 g of Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer MateπalScience AG; in a 3 l reaction vessel with stirrer and reflux condenser; Germany), diluted with 69.7 g of N-methylpyrrohdone and homogenized at 90 ^° C. 306.4 g Isophorondnsocyanat are then added and stirred the reaction mixture at 90 ⁰ C until the NCO value is 9.7% with stirring. Then it is diluted with 442 g of acetone and 75 g of 1,4-cyclohexanedimethanol and stirred at 55 ⁰ C until an NCO value of 2.2% is reached. Then, a chain extending solution of 23.3 g isophoronediamine, 3.9 g Ethylendiamm, 2 g Diethylentπamm, diluted with 25 g of acetone was added and stirred at 5O ⁰ C for 30 minutes. After addition of 26.4 g Tπethylamin to neutralize the carboxyl groups is heated by addition of 1250 g to 6O ⁰ C heated distilled water. After the distillative removal of the acetone, the polyurethane dispersion 3) according to the invention is obtained with a solids content of 36%, a viscosity of 53 mPas / 23 ° C., a pH of 7.6 and an average particle size of 36 nm.

Polyurethane dispersion 4)

In a 3 l reaction vessel equipped with a stirrer and reflux condenser are added 7.4 g of 1,4-butanediol, 37.2 g of dimethylolpropionic acid and 345 g of Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer Mateπal Science AG, Germany ), diluted with 70 g of N-methylpyrrohdone and homogenized at 90 ^° C. 333 g Isophorondnsocyanat are then added and stirred the reaction mixture at 90 ⁰ C until the NCO value is 10.4% under stirring. Then it is diluted with 460 g of acetone and 85.2 g of 1,4-cyclohexanedimethanol added and stirred at 55 ⁰ C until an NCO value of 2.3% is reached. Then, a chain extension solution of 19.1 g of isophoronediamine, 4 g of hydrazine hydrate, 3.4 g of diethylenetriamine, diluted with 25 g of acetone is added and stirred at 50 ° C for 30 minutes. After addition of 25.2 g of triethylamine to neutralize the carboxyl groups is heated by the addition of 1200 g at 60 ⁰ C heated distilled water. After the distillative removal of the acetone, the polyurethane dispersion 4) according to the invention is obtained with a solids content of 38%, a viscosity of 145 mPas / 23 ° C., a pH of 7.9 and an average particle size of 67 nm.

Polyurethane dispersion 5)

In a 3 1 reaction vessel with stirrer and reflux condenser, 7.4 g of 1, 4-butanediol, 37.2 g of dimethylolpropionic acid and 345 g Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer MaterialScience AG; Germany), diluted with 70 g of N-methylpyrrolidone and homogenized at 90 ^° C. Then, with stirring, 333 g of isophorone diisocyanate are added and the reaction mixture is stirred at 90 ^° C. until the NCO value is 10.0%. Then it is diluted with 460 g of acetone and 85.2 g of 1,4-cyclohexanedimethanol added and stirred at 55 ⁰ C until an NCO value of

2.2% is reached. Then a chain extension solution of 8.5 g of isophoronediamine, 6.4 g

Hydrazine hydrate, 3.44 g of diethylenetriamine, diluted with 20 g of acetone and at 50 ⁰ C 30

Stirred for minutes. After addition of 25.2 g of triethylamine to neutralize the carboxyl groups is heated by the addition of 1240 g at 60 ⁰ C heated distilled water. After the distillative removal of the acetone, the polyurethane dispersion 5) according to the invention is obtained with a solids content of 38%, a viscosity of 90 mPas / 23 ° C., a pH of 7.7 and an average particle size of 50 nm.

Polyurethane dispersion 6)

In a 3 1 reaction vessel with stirrer and reflux condenser, 5.2 g of 1, 4-butanediol, 36.9 g of dimethylolpropionic acid and 330 g Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer MaterialScience AG; Germany), diluted with 68.4 g of N-methylpyrrolidone and homogenized at 90 ^° C. Subsequently, 333 g of isophorone diisocyanate are added with stirring and the reaction mixture is stirred at 90 ^° C. until the NCO value is 11.0%. Then it is diluted with 460 g of acetone and 80.8 g of 1,4-cyclohexanedimethanol added and stirred at 55 ⁰ C until an NCO value of 2.75% is reached. Then, a chain extension solution of 19.1 g of isophoronediamine, 6.2 g of hydrazine hydrate, 3.4 g of diethylenetriamine, diluted with 25 g of acetone is added and stirred at 50 ⁰ C for 90 minutes. After addition of 25 g of triethylamine to neutralize the carboxyl groups is dispersed by adding 1100 g heated to 60 ⁰ C distilled water. After the distillative removal of the acetone, the polyurethane dispersion 6) according to the invention is obtained with a solids content of 40%, a viscosity of 70 mPas / 23 ° C., a pH of 7.7 and an average particle size of 75 nm.

Polyurethane dispersion 7 ^" )

In a 3 l reaction vessel with stirrer and reflux condenser, 140.5 g of polyester b), 38.6 g of dimethylolpropionic acid and 247 g of Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer Material Science AG, Germany ), diluted with 70 g of N-methylpyrrolidone and homogenized at 9O ⁰ C. 306.4 g of isophorone diisocyanate are then added and the reaction mixture is stirred at 90 ⁰ C until the NCO value is 9.2% with stirring. Then it is diluted with 440 g of acetone and 73.3 g of 1,4-cyclohexanedimethanol was added and stirred at 55 ⁰ C until an NCO value of 2.1% is reached. Then, a chain extending solution of 22.4 g isophoronediamine, 4.2 g of ethylenediamine, 2 g diethylenetriamine, diluted and stirred at 5O ⁰ C for 30 minutes with 30 g of acetone. After addition of 26.2 g of triethylamine to neutralize the carboxyl groups is heated by the addition of 1140 g at 60 ⁰ C heated distilled water. After the distillative removal of the acetone, the polyurethane dispersion 7) according to the invention is obtained with a solids content of 40%, a viscosity of 167 mPas / 23 ^° C., a pH of 7.6 and an average particle size of 28 nm.

Polyurethane dispersion 8)

In a 3 1 reaction vessel with stirrer and reflux condenser, 179.4 g of polyester b), 38.4 g of dimethylolpropionic acid and 259.2 g of Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer MaterialScience AG; Germany) were weighed, diluted with 67g of N-methylpyrrolidone and homogenized at 90 ⁰ C. 306.4 g of isophorone diisocyanate are then added and the reaction mixture is stirred at 90 ⁰ C until the NCO value was 8.1%, with stirring. Then it is diluted with 440 g of acetone and 68.2 g of 1, 4-cyclohexanedimethanol and stirred at 55 ⁰ C until an NCO value of 2.6% is reached. Then a chain extension solution of 22.4 g of isophoronediamine, 4.2 g of ethylenediamine, 2.0 g of diethylenetriamine, diluted with 25 g of acetone is added and stirred at 50 ⁰ C for 30 minutes. After addition of 26.1 g of triethylamine to neutralize the carboxyl groups is heated by the addition of 1200 g at 60 ⁰ C heated distilled water. After the distillative removal of the acetone, the polyurethane dispersion 8 according to the invention is obtained. with a solids content of 38%, a viscosity of 73 mPas / 23 ° C., a pH of 7.6 and an average particle size of 34 nm.

Polyurethane dispersion 9)

In a 3 l reaction vessel with stirrer and reflux condenser, 204.1 g of polyester b), 38.1 g of dimethylolpropionic acid and 306 g of Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer MateπalScience AG, Germany) weighed, diluted with 70 g of N-methylpyrrolidone and homogenized at 90 ⁰ C. Then, while stirring, 230 g of isophorone isocyanate are added and the reaction mixture is stirred at 90 ^° C. until the NCO value is 4.5%. Then it is diluted with 440 g of acetone and 25.6 g of 1,4-cyclohexanedimethanol and stirred at 55 ⁰ C until an NCO value of 2.2% is reached. Then, a chain extension solution of 16.8 g of isophorone diamine, 3.1 g of ethylene diamine, 1.5 g of diethylenetriamine, diluted with 20 g of acetone is added and stirred at 50 ⁰ C for 30 minutes. After addition of 25.9 g of triethylamine to neutralize the carboxyl groups is dispersed by the addition of 1100 g of distilled water. After the distillative removal of the acetone, the polyurethane dispersion 9) according to the invention is obtained with a solids content of 43%, a viscosity of 162 mPas / 23 ° C., a pH of 7.4 and an average particle size of 29 nm.

Polyurethane dispersion 10)

In a 3 1 reaction vessel with stirrer and reflux condenser, 107.7 g of polyester b), 38.4 g of dimethylolpropionic acid and 283 g of Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer MateπalScience AG, Germany) weighed, diluted with 70 g of N-ethylpyrrolidone and homogenized at 90 ⁰ C. 306.4 g Isophorondnsocyanat are then added and stirred the reaction mixture at 90 ⁰ C until the NCO value is 9.0% with stirring. Then it is diluted with 440 g of acetone and 75 g of 1,4-cyclohexanedimethanol and stirred at 55 ⁰ C until an NCO value of 2.2% is reached. Then a chain extension solution of 18 g isophoronediamine, 3.9 g

Hydrazine hydrate, 3.4 g Diethylentπamin, diluted with 25 g of acetone and added at 50 ⁰ C 60

Stirred for minutes. After addition of 26.1 g of triethylamine to neutralize the carboxyl groups is heated by the addition of 1150 g at 60 ⁰ C heated distilled water. After the distillative removal of the acetone, the polyurethane dispersion 10) according to the invention is obtained with a solids content of 42%, a viscosity of 88 mPas / 23 ° C., a pH of 7.7 and an average particle size of 49 nm. Polyurethane dispersion 11)

In a 3 1 reaction vessel with stirrer and reflux condenser 218.1 g of polyester b), 37.1 g of dimethylolpropionic acid, 13.4 g of 1, 4-butanediol and 297.5 g Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer Material Science AG; Germany), diluted with 68.7 g of N-methylpyrrolidone and 322 g of acetone and homogenized. Then, with stirring, 223.4 g of isophorone isocyanate are added and the reaction mixture is stirred at 55 ° C. until the NCO value is 1.8%. Then a chain extension solution of 16.4 g of isophoronediamine, 3 g of ethylenediamine, 1.5 g Diethylentπamm, diluted with 25 g of acetone was added and stirred at 50 ⁰ C for 45 minutes. After addition of 25 g Tπethylamin to neutralize the carboxyl groups is dispersed by the addition of 1120 g of distilled water. After the distillative removal of the acetone, the polyurethane dispersion 11) according to the invention is obtained with a solids content of 40%, a viscosity of 35 mPas / 23 ° C., a pH of 7.6 and an average particle size of 42 nm.

Comparative Example 12), polyurethane dispersion based on 4,4'-diisocyanatodicyclohexylmethane

27 g of dimethylolpropionic acid and 250.8 g of Desmophen® C2200 (difunctional polycarbonate polyol, number average molecular weight (M _n ) 2000 g / mol, Bayer Material Science AG, Germany) are weighed into a 2 l reaction vessel equipped with a stirrer and reflux condenser, with 50 g of N-methylpyrrohdone diluted and homogenized at 90 ⁰ C. 194.5 g of Desmodur® W (4,4'-Dπsocyanatodicyclohexylmethan, Bayer MaterialScience AG, Leverkusen, Germany) are then, with stirring, and 44.9 g Isophorondnsocyanat added and stirred the reaction mixture at 90 ⁰ C until the NCO value 9 , 1%. Then it is diluted with 264 g of acetone, 60.9 g of 1, 4-cyclohexanedimethanol and stirred at 55 ⁰ C until an NCO value of 1.8% is reached. Then, a chain extension solution of 15.4 g of isophoronediamine and 2.5 g of ethylenediamine diluted with 25 g of acetone is added and stirred at 50 ^° C. for 15 minutes. After addition of 18.3 g Tπethylamin to neutralize the carboxyl groups is heated by the addition of 880 g at 60 ⁰ C heated distilled water. After the separation by distillation of the acetone, the polyurethane dispersion Comparative Example 12) based on 4,4'-dinocyanato-cyclohexylmethane, having a solids content of 40%, a viscosity of 80 mPas / 23 ° C, a pH of 7 , 7 and a mean particle size of 50 nm. Comparative Example 13) Polyurethane dispersion with aliphatic polyester

In a 3 1 reaction vessel with stirrer and reflux condenser 263.6 g of a difunctional polyester having the number average molecular weight (M _n ) of 2250 g / mol, prepared by esterification of adipic acid and 1, 6-hexanediol, and 27.6 g of dimethylolpropionic acid weighed, diluted with 47.6 g of N-methylpyrrolidone and homogenized at 90 ⁰ C. Then 194.5 g of Desmodur® W and 44.9 g of isophorone diisocyanate are added with stirring and the reaction mixture is stirred at 90 to 100 ⁰ C until the NCO value is 9%. Then it is diluted with 353 g of acetone, 61.4 g of 1, 4-cyclohexanedimethanol and stirred at 58 ⁰ C until an NCO value of 1.6% is reached. Then, a chain extension solution of 15.4 g of isophoronediamine and 2.8 g of diethylenetriamine diluted with 25 g of acetone is added and stirred at 50 ^° C. for 15 minutes. After addition of 18.7 g of triethylamine to neutralize the carboxyl groups is heated by the addition of 850 g at 60 ⁰ C heated distilled water. After separation by distillation of the acetone, the polyurethane dispersion Comparative Example 13) is obtained based on an aliphatic polyester having a solids content of 41%, a viscosity of 106 mPas / 23 ° C., a pH of 8.1 and an average Particle size of 55 nm.

test results:

The dispersions of the invention were coated with 9% of a high-boiling film former (eg tripropylene glycol monobutyl ether or n-ethylpyrrolidone), 1% of a hydrocarbon-based defoamer, 7% of a colloidal silica (mean particle size 10-20 mm), 7% of a cationically stabilized oxidized polyethylene wax, 1 5% of a zirconium carbonate crosslinker, 0.7% of a leveling agent (polyether-modified polydimethylsiloxane) and 0.5% of an epoxy silane added, adjusted to pH 8 with ammonia solution, diluted with the 6-fold water to application viscosity, on degreased substrates (eg , cold rolled galvanized steel sheets, eg Arcelor Galvalume® or cold rolled hot-dip galvanized steel sheets) in an amount of about 10 ml / m ^{2 applied} by means of a roll coater and dried at 70 ⁰ C pmt (peak metal temperature).

The dry film thickness was about 2 μm. All coatings were clear, colorless and silky-glossy.

The coated substrates were subjected to the following tests after 24 hours: 1) The corrosion protection is tested by a salt spray test according to DESf EN Iso 9227 for 240 or 480 hours. To assess the test values, the percentage area corrosion is determined. The following test values are possible: At 240 hours: Excellent = surface corrosion 0 to 5%; good = surface corrosion 5 to 10%; acceptable = area corrosion 10 to 15%; insufficient = surface corrosion> 15%.

At 480 hours: Excellent = Area corrosion 0 to 5%; good = surface corrosion 5 to 20%; acceptable = surface corrosion 20 to 40%; insufficient = surface corrosion> 40%.

2) The alkali resistance is determined by means of a NaOH drop test. In this case, drops of an aqueous 4% NaOH solution are dropped onto the substrate and after different periods of time (30 seconds / minutes / 2 minutes / 3 minutes / 4 minutes / 5

Minutes) assessed the damage. The following test values are possible: 5 points = no change, 4 points = minimal discoloration; 3 points = medium discoloration, 2 points = strong discoloration, 1 point = very strong discoloration / damage. In this case, the points determined for the individual periods are added together, the best achievable result is 30 points (6 x 5), the worst result is 6

Points (6x1). 28-30 points = very good; 26-27 points = good, <26 points insufficient.

3) The test for resistance to cleaning agents is determined by spraying with a defined amount of an alkaline cleaning fluid (Cardoclean® S 5201 or Cardoclean® S5080, both Chemetall GmbH, Frankfurt, Germany) at temperatures of 60 to 65 ⁰ C for 2 minutes. This will be coated panels of size 12 x

Weigh 9 cm before and after spraying (with 1 bar pressure) with cleaning liquid and determine the weight loss in g / m ² determined by the cleaning. A weight loss of <0.4 g / m ² is judged to be excellent, 0.4 to 0.6 g / m ² is good,> 0.6 to 0.8 g / m ² is acceptable,> 0.8 g / m ² is insufficient.

4) The thermostability test is performed by heating the panels for 10 minutes

200 ⁰ C or for 60 minutes at 200 ⁰ C or for 24 hours at 150 ⁰ C. The color deviation (Δ E) is evaluated as follows: <2 is excellent, 2 to 3 is sufficient,> 3 is insufficient. The following results were obtained:

The sheet metal surfaces were completely evenly coated, there were no defects, flow defects or other film irregularities. The film hardness, film elasticity and adhesion (cross hatch test) were excellent. Stacking strength and ductility fully met the requirements The dispersions of the invention are convincing in terms of corrosion protection properties and thermal stability under various conditions. The resistance to cleaning agents is excellent, the results of the NaOH drop test are also very good.

The dispersions of the invention thus meet all the requirements and also convince by the low VOC (volatile organic component) content.

In addition, the dispersions of the invention also exhibited excellent storage stability.

The dispersion of Comparative Example 12) based on 4,4'-diisocyanato-dicyclohexyl methane meets all requirements in the corrosion protection test, but not in the NaOH drop test. The thermal stability under prolonged exposure to heat is only sufficient, and overall slightly weaker than the products based on isophorone diisocyanate. The resistance to cleaning fluid also does not meet the requirements.

The dispersion of Comparative Example 13) based on an aliphatic polyester does not meet the requirements in the corrosion protection test and in the NaOH drop test. The thermal stability during prolonged exposure to heat is only sufficient. The resistance to cleaning fluid is excellent.

These dispersions of the invention also meet all the requirements.

Claims

claims 1. Polyurethane dispersions containing reaction products of the following components: a) from 20 to 45% by weight of at least one, at least difunctional, aliphatic polyisocyanate component consisting of at least 75% of isophorone isocyanate, b) 30 to 65 wt .-% of at least one polyol component having a number average molecular weight (M _n ) of 800 to 6000 g / mol, consisting of at least 50% of at least one aliphatic polycarbonate polyol and / or an aromatic polyester polyol based on isophthalic acid, terephthalic acid and / or phthalic acid or phthalic anhydride, c) 1.5 to 8 wt .-% of at least one hydrophiherenden component having in addition to at least one hydrophilic group one or two amino or hydroxyl groups, d) 1 to 15% by weight of at least one low molecular weight diol and / or triol component, e) 0.3 to 8 wt .-% of at least one amino group and / or an amino and hydroxyl groups-containing chain extension component, and f) 0 to 15 wt .-% of a monofunctional hydrophobizing component. 2. Polyurethane dispersions according to claim 1 containing reaction products of the following components: a) from 20 to 45% by weight of at least one, at least difunctional, aliphatic polyisocyanate component consisting of at least 90% of isophorone isocyanate, b) 30 to 65 wt .-% of at least one polyol component having a number average molecular weight (M _n ) of 800 to 4000 g / mol, consisting of at least 75% of at least one aliphatic polycarbonate polyol and / or an aromatic Polyester polyol based on isophthalic acid, terephthalic acid and / or phthalic acid or phthalic anhydride, c) from 1.5 to 5.5% by weight of at least one hydrophilicizing component having carboxylic acid groups which, in addition to at least one hydrophilic acid group, has one or two amino or hydroxyl groups, d) from 1 to 12% by weight of at least one low molecular weight diol and / or triol component, e) 0.5 to 6 wt .-% of at least one amino group and / or one and amino and hydroxyl groups containing chain extender component, f) 0 to 8 wt .-% of a monofunctional hydrophobizing component. 3. Polyurethane dispersion according to claim 1 or 2, characterized in that component b) consists of 100% of at least one aliphatic polycarbonate diol and / or an aromatic polyester diol based on isophthalic acid, terephthalic acid and / or phthalic acid or phthalic anhydride. 4. Polyurethane dispersion according to claim 1 or 2, characterized in that as component e) a combination of isophoronediamine, diethylenetriamine and hydrazine hydrate or ethylenediamine is included. 5. polyurethane dispersion according to claim 1 or 2, characterized in that as component e) a combination of 50 to 90% isophoronediamine, 3 to 25% diethylenetriamine and 5 to 35% hydrazine hydrate or ethylenediamine is included, wherein the sum of the percentages the entire amount of the component contained in the polyurethane dispersion e) relates. 6. polyurethane dispersion according to claim 1 or 2 containing reaction products of the following components: a) from 20 to 45% by weight of at least one, at least difunctional, aliphatic polyisocyanate component consisting of at least 90% of isophorone diisocyanate, b) 30 to 65 wt .-% of at least one polyol component with a Molecular weight of 800 to 4000 g / mol, consisting of at least 75% of at least one aliphatic polycarbonate polyol based on hexanediol and / or an aromatic polyester polyol based on isophthalic acid, terephthalic acid and / or phthalic acid or phthalic anhydride, c) 1.5 to 5.5% by weight of dimethylolpropionic acid d) 1 to 12% by weight of 1,4-cyclohexanedimethanol and / or butanediol and / or neopentyl glycol, e) 0.5 to 6% by weight of a chain extender component comprising isophorone diamine and ethylene diamine and / or hydrazine hydrate and diethylene triethylene glycol, f) 1 to 8 wt .-% of a monofunctional hydrophobizing component. 7. A process for the preparation of the polyurethane dispersions according to one or more of claims 1 to 6, characterized in that the components a) to d) and optionally f), optionally in the presence of catalytically active substances and / or neutralizing agents, in one or several consecutive Reaction steps are reacted with one another to give an isocyanate-functional prepolymer, the ratio of NCO groups to OH, NH 2, NH groups being 2.2 to 1.2 to 1, preferably 1.85 to 1.25 to 1, wherein solvent and / or neutralizing agent are added before, during and / or after the reaction, wherein after reaction of components a) to d) and optionally f) either a chain extension with component e) is carried out in organic solution, wherein subsequently in or with Water is dispersed, or wherein a chain extension with component e) is carried out in aqueous dispersion and wherein the solvent is removed by distillation or completely or partially during or after the dispersing step. 8. A process for preparing the polyurethane dispersions according to one or more of claims 1 to 6, characterized by a two-stage preparation process of the isocyanate-functional prepolymers in at least one non-isocyanate-reactive solvent, wherein in the first reaction step, the components a), b), c) and optionally f) optionally in the presence of catalytically active substances are reacted until the theoretical NCO content is reached or slightly below and in a second reaction step, the component d) is added and reacted until the isocyanate-functional prepolymer reaches the theoretical isocyanate value or slightly below has, and then, if appropriate, after further dilution with solvent, a chain extension reaction with component e) is carried out at 30 to 55 ⁰ C in the organic phase and is then dispersed by adding water or by dispersing in water, before or during dispersing, a sufficient amount of neutralizing agent has been added, and wherein during or after the dispersing, the solvent is distilled off in whole or in large part. 9. A process for preparing the polyurethane dispersions according to claim 7 or 8, characterized in that a solvent mixture is used, consisting of acetone and a non-isocyanate-reactive solvent having a boiling point> 12O ⁰ C, such as N-methylpyrrolidone, N-ethylpyrrolidone or others Solvents and the proportions of the two solvents are chosen so that the acetone is 70 to 98% of the total amount of solvent and the acetone is then completely distilled off again, while the higher-boiling Solvent remains in the dispersion. 10. Use of the polyurethane dispersions according to one or more of claims 1 to 6 alone or in combination with other polymers, dispersions or / and aqueous solutions, such as. Polyacrylate dispersions, polyacrylate emulsions, alkyd dispersions, polyurethane-polyacrylate dispersions, Styrene butadiene latices, other polyurethane dispersions, polyester dispersions or solutions, aqueous or water-dilutable epoxy resins, epoxy resins, polyvinyl chloride dispersions, polyvinylidene chloride dispersions, Polyvinylpyrrolidone dispersions, polyvinylimidazole dispersions, polyethylene dispersions, acrylonitrile (co) polymer dispersions, styrene (co) polymer dispersions, Butadiene (co) polymer dispersions, vinylpyrrolidone (co) polymer dispersions, aqueous phenolic resins, aqueous condensation polymers, aqueous addition polymers, polymer dispersions, cellulose, cellulose acetate and / or cellulose butyrate, dispersed, water-soluble or water-dispersible polyvinyl alcohols and / or possibly proportionally hydrolyzed polyvinyl esters and / or eg with silanol groups, alkoxysilane groups, acetoacetyl groups or other reactive groups modified polyvinyl alcohols or polyvinyl esters, optionally modified or optionally proportionally hydrolyzed Polyethylenvinylestercopolymere or Polyethylenvinylalkoholcopolymere, Polyvinyletherdispersionen or solutions and / or in combination with low molecular weight, oligomeric and / or polymeric Crosslinkers such as optionally containing hydrophilic groups polyisocyanates with free or blocked polyisocyanate groups, with polyaziridines, with polyepoxides, with polyalkoxysilanes, with carbodiimides, with polycarbodiimides, with polysiloxanes, with di- or polyhydrazides or amines, with carbonyl groups containing polymers and / or crosslinkers and / or with Ammetworketzerharzen, for example based on melamine or urea, in or as a lacquer, coating and / or size. 11. Use of the polyurethane dispersions according to one or more of Claims 1 to 6 for the passivation and corrosion protection of metallic substrates such. Sheet metal, strip steel, metal strips, metal wires, metal rods, metal mesh, metal mesh, metal three-dimensional sheets, etc., e.g. based on various steel alloys, iron, cast iron, aluminum, magnesium, titanium, galvanized materials.