CN1646647A - Aqueous coating composition based on epoxybutene polyethers - Google Patents

Abstract

The invention relates to water-dilutable polyurethanes containing structural units derived from 3, 4-epoxy-1-butene, and to aqueous dispersions containing said polyurethanes. The invention also relates to a method for producing said polyurethanes and to the use thereof as aqueous oxidatively drying and/or UV-crosslinking coatings.

Description

Aqueous coating composition based on epoxybutylene polyether

technical field

The present invention relates to water-dilutable polyurethanes containing structural units derived from 3,4-epoxy-1-butene, as well as aqueous dispersions containing such polyurethanes, processes for their preparation and their use as aqueous oxidative-drying and/or ultraviolet - Application of a crosslinking coating composition.

Background technique

Polymeric compounds containing 3,4-epoxy-1-butene structural units are known in principle. For example, EP-A 0 217 660 describes a process for the preparation of poly(α-hydroxycarboxylic acid) copolymers using ethylenically unsaturated epoxides.

US-A 5,393,867 discloses hydroxy-functional polyethers obtained by the polymerization of 3,4-epoxy-1-butene with a palladium catalyst.

EP-A 0 859 021 describes a compound having pendant vinyl groups by means of (a) a compound containing at least one vinyl group and at least one epoxy group, (b) a polyvalent compound or an anhydride thereof and optionally (c) reaction between CH-acid compounds and their epoxidized derivatives.

WO 00/66646 describes oil-free, oxidation-drying polyester resins obtained by derivatization of carboxy-functional polyesters with 3,4-epoxy-1-butene, and the combination of such resins with organic solvents and drying catalysts in Application in room temperature dry paint.

Finally, WO 00/66649 describes polyether-alcohol-based coating compositions which can be prepared by ring-opening polymerization of 3,4-epoxybutene with water or alcohol. The polyether alcohols prepared in this way can be used as reactive diluents or binders in oxidatively drying coatings and as structural units of such binders.

The disadvantages of the water-based one-pack paints known to date in coatings technology are, for example, that the drying of water-based paints at room temperature by oxidation-crosslinking often takes place very slowly, even with the addition of driers as drying catalysts, and that only moderate films can be obtained hardness. On the other hand, UV-curable waterborne one-pack paints exhibited insufficient crosslinking in areas where the UV radiation dose was low or not received at all (shaded areas). The paint film has properties at a lower level in this field.

Summary of the invention

It is therefore an object of the present invention to provide an aqueous dispersion which can be oxidatively-dried and/or crosslinked with UV light and which can be processed into one-pack paints with high performance, especially in terms of film appearance, hardness, Resistant to solvents and weathering as well as fast drying.

This has now been achieved by providing a water dilutable polymer comprising urethane groups and 3,4-epoxy-1-butene structural units which can be used as a one-pot aqueous dispersion Base.

Accordingly, the present invention provides a water-dilutable polymer comprising urethane groups and having ionic and/or potentially ionic groups, characterized in that the polymer comprises recurring units (A1) of the general formula (I) and/or or repeating units (A2) of general formula (II),

-O-CH₂-CH＝CH-CH₂-

-O-CH ₂ -CH=CH-CH ₂ -

(II).

Repeat unit A1, A2 or mixture A1/A2 in the polymer as a block

form or in the form of a mixed block of two structural units with p repeating units, wherein n, m and p each represent an integer from 3 to 100.

The A1 or A2 structural units can also be distributed in different ways in the copolymer.

The content of A1 and/or A2 units in the polymer of the present invention is 2-80 wt%, preferably 5-50 wt%, especially preferably 8-35 wt%.

The structural units A1 and/or A2 contained in the polymer of the present invention can be obtained by ring opening of the epoxy ring of 3,4-epoxy-1-butene. Here, 3,4-epoxy-1-butene may also add (one or more times) to the nucleophilic center of the polymer or oligomer chain via ring-opening of the epoxy ring, for example, to COOH -, OH- or NH-functional chain ends. On the other hand, polyetherol-oligomers or polymers having one or more hydroxyl groups prepared by ring-opening polymerization of 3,4-epoxy-1-butene can also be used as units constituting the polyurethane chain , optionally in the presence of other monomers polymerizable under these conditions, for example, ethylene oxide, propylene oxide or butylene oxide. The structural units A1 and/or A2 are preferably incorporated into the polyurethane by incorporation into hydroxyl-functional polyether polyols.

Polyether polyols can be composed entirely of repeating units A1 and/or A2 (homopolymers) or, in addition to initiator components incorporated into the chain, also as a compound with other monomers which can be polymerized under such conditions. Alloys such as copolymers with ethylene oxide, propylene oxide or butylene oxide are present. Macroinitiators containing the repeat units mentioned above can also be used for the purpose of preparing polyether-alcohols by homopolymerization of 3,4-epoxy-1-butene. Suitable catalysts for the preparation of polyether-alcohols are, for example, KOH, trifluoromethanesulfonic acid or its salts with yttrium or other lanthanide metals, palladium(0) compounds such as tetrakis(triphenylphosphine)- Palladium(O).

Preferably, double metal cyanide catalysis (DMC catalysis) is used in the ring-opening polymerization of 3,4-epoxybutene to prepare polyether-alcohols with alcohols as starter molecules. The polymerization of DMC catalysts and epoxides employing such catalysts is described, for example, in EP-A 0 700 949.

The polymers of the invention comprise 1 to 40% by weight of urethane groups [NHCOO], preferably 2 to 30% by weight of urethane groups, especially preferably 5 to 25% by weight, more especially preferably 15 to 25% by weight of urethane groups.

The polymers of the invention additionally contain 9 to 100 meq/100 g of ionic and/or potentially ionic groups in order to achieve dispersibility or solubility in aqueous media. The total content of ionic and/or potentially ionic groups is preferably 20-60 meq/100g, especially preferably 25-50 meq/100g.

The water-dilutable polymers according to the invention are preferably reaction products A) comprising the following components,

(a1) 5-80 wt%, preferably 10-60 wt% polyisocyanate,

(a2) 10-80% by weight, preferably 40-70% by weight, of polyols and/or polyamines with an average molecular weight _Mn of at least 400,

(a3) 2 to 15% by weight, preferably 3 to 10% by weight, of compounds containing at least one group reactive with isocyanate groups and at least one ionic and/or potentially ionic group,

(a4) 0 to 20 wt%, preferably 1 to 10 wt% of low molecular weight polyols and/or secondary polyamines,

(a5) 0～20wt% chain terminator,

(a6) 0 to 20% by weight of a chain extender which contains at least two groups reactive with isocyanate groups and is different from (a2), (a3) and (a4).

The average molecular weight _Mn of the water-dilutable polymer of the present invention is 1,000-50,000, preferably 1,600-10,000.

The polyisocyanates, preferably diisocyanates (a1), are compounds known in the field of polyurethanes and lacquers, for example aliphatic, cycloaliphatic or aromatic diisocyanates.

Suitable are compounds of the general formula Q(NCO) ₂ , in which Q represents a hydrocarbyl group of 4 to 40 carbon atoms, preferably 4 to 20 carbon atoms. Q is preferably an aliphatic C ₄ -C ₁₂ group, a cycloaliphatic C ₆ -C ₁₅ group, an aromatic C ₆ -C ₁₅ group or an araliphatic C ₇ -C ₁₅ group.

Particularly preferred diisocyanates are, for example, tetramethylene-diisocyanate, hexamethylene-diisocyanate, dodecamethylene-diisocyanate, 1,4-diisocyanato-cyclohexane, 3-isocyanate Atomethyl-3,5,5-trimethylcyclohexyl-isocyanate (isophorone diisocyanate), 4,4'-diisocyanatodicyclohexylmethane, 4,4'-diisocyanate Ato-2,2-dicyclohexylpropane, 1,4-diisocyanatobenzene, 2,4- or 2,6-diisocyanatotoluene and mixtures of these isomers, 4,4' or 2,4'-diisocyanatodiphenylmethane, 4,4'-diisocyanato-2,2-diphenylpropane, p-xylene-diisocyanate and α,α,α',α '-Tetramethyl-m-or-p-xylene-diisocyanate and mixtures of these compounds.

In addition to these simple polyisocyanates, those which contain heteroatoms in the group linking the isocyanate groups and/or have a functionality greater than or equal to 2 NCO groups per molecule are also suitable. Examples of such compounds are compounds containing carbodiimide groups, allophanate groups, isocyanurate groups, carbamate groups, acylated urea groups, iminooxadiazine-di Polyisocyanates of ketone groups, uretdione groups or biuret groups and 4-isocyanato-methyl-1,8-octane-diisocyanate (nonane-triisocyanate).

For other suitable polyisocyanates see, for example, DE-A 29 28 552, p.14-16. Mixtures of these compounds are also suitable.

The average molecular weight _Mn of component (a2) is preferably 400-5,000, especially preferably 800-2,000. The hydroxyl value or amine value is generally between 22-400, preferably 50-200, especially preferably 80-160 mg KOH/g.

Suitable polyols (a2) are compounds known from the field of polyurethane chemistry, for example polyether-polyols, polyester-polyols, polycarbonate-polyols, polyester-amide-polyols, polyamide-polyols , epoxy resin-polyols and their reaction products with _CO2 , polyacrylate-polyols and similar compounds. Such polyols can also be used as mixtures, as described, for example, in DE-A 20 20 905, DE-A 23 14513 and DE-A 31 24 784 and EP-A 0 120466.

Instead of hydroxyl groups, the compounds of component (a2) may also contain primary or secondary amino groups (a proportion or all) as NCO-reactive groups.

Aspartate esters of the abovementioned molecular weights, for example those mentioned in EP-A 0 403 921, p. 4-5, are also suitable as component (a2). Such secondary amines can also be used in mixtures with polyols.

Preferred polyols are polyether- and polyester-polyols, and particular preference is given to those which have only hydroxyl end groups and a functionality of 3 or less, preferably 2.8-2.

Preferred polyester-polyols are the well-known di- and optionally poly(tri,tetra)hydric alcohols with mono-, di- and optionally poly(tri,tetra)carboxylic acids, or hydroxycarboxylic acids or internal Polycondensation products of esters. Instead of the free polycarboxylic acids, it is also possible to use the anhydrides of the corresponding polycarboxylic acids or the corresponding polycarboxylates of lower alcohols for the preparation of the polyesters. Examples of suitable diols are ethylene glycol, butanediol, diethylene glycol, triethylene glycol, polyalkylene glycols, e.g. polyethylene glycol, furthermore propylene glycol, butane-1,4-diol , hexane-1,6-diol, neopentyl glycol or neopentyl glycol hydroxypivalate. Hexamethylene-1,6-diol, neopentyl glycol or neopentyl glycol hydroxypivalate are preferred compounds. Here, examples also include trimethylolpropane, glycerin, erythritol, pentaerythritol, trimethylolbenzene or trishydroxyethyl isocyanurate as polyhydric alcohols that are optionally used concomitantly.

Suitable di- or polycarboxylic acids are, for example, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid, adipic acid, nonanedicarboxylic acid, Diacid, sebacic acid, glutaric acid, tetrachlorophthalic acid, maleic acid, fumaric acid, itaconic acid, malonic acid, suberic acid, 2-methylsuccinic acid, 3,3-di Ethylglutaric acid, 2,2-dimethylsuccinic acid, trimellitic acid, or pyromellitic acid. Anhydrides of these acids can also be used, if present. Thus, for the purposes of the present invention, acid anhydrides are encompassed within the term "acid". Monocarboxylic acids can also be used as long as the polyol has an average functionality of two or more.

Hydroxycarboxylic acids suitable for the preparation of polyester-polyols having hydroxyl end groups are, for example, hydroxycaproic acid, hydroxybutyric acid, hydroxydecanoic acid, hydroxystearic acid and the like. Suitable lactones are, for example, caprolactone, butyrolactone and the like.

Particularly preferred are polyether-polyols which contain A1 and/or A2 repeating units completely or partly, as well as polyoxyethylene-polyols, polyoxypropylene-polyols, polyoxybutylene-polyols with terminal hydroxyl groups polyol or polytetrahydrofuran.

The polymers according to the invention may additionally comprise polyoxyalkylene ethers which do not contain A1 and/or A2 repeating units but which carry at least one hydroxyl or amino group per molecule, for example from alcohols and from polyoxyethylene ethers with a molecular weight of 400 to 40,000 / Polyoxypropylene block preparation.

In a preferred embodiment of the invention, component (a2) comprises at least a proportion of oligoesters or polyesters containing mono- and/or polyunsaturated fatty acids. Suitable fatty acids are, for example, coconut fatty acid, soybean fatty acid, sunflower fatty acid, castor fatty acid, ricinene fatty acid, arachis fatty acid, tall oil fatty acid or conjuene fatty acid. Also suitable are monocarboxylic acids such as benzoic acid, tert-butylbenzoic acid, hexahydrobenzoic acid, 2-ethylhexanoic acid, isononanoic acid, decanoic acid or octadecanoic acid. Soy fatty acid or a mixture of 70-100 wt% soy fatty acid and 0-30 wt% benzoic acid is preferably used as monocarboxylic acid. The polymers according to the invention therefore preferably, in addition to the allyl double bonds present in the structural units A1 and/or A2, additionally contain C═C double bonds of mono- or polyunsaturated fatty acids.

In another preferred embodiment, component (a2) comprises at least a proportion of polyols which additionally contain C═C in the acrylate and/or methacrylate units A3) of the general formula (III) double bond.

Preference is given to using polyester-acrylates which contain hydroxyl groups and have a hydroxyl value of 30 to 300 mg KOH/g. A total of seven types of monomeric components can be used to prepare hydroxy-functional polyester-acrylates:

1. (Cyclo)alkanediols, for example, diols having a (cyclo)aliphatically bonded hydroxyl group in the molecular weight range from 62 to 286, such as ethylene glycol, 1,2- and 1 , 3-propanediol, 1,2, 1,3 and 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,4- Dimethanol, 1,2- and 1,4-cyclohexanediol, 2-ethyl-2-butylpropanediol and diols containing ether-oxygen, e.g. diethylene glycol, triethylene glycol, tetraethylene glycol , dipropylene glycol, tripropylene glycol or polyethylene glycol, polypropylene glycol or polytetramethylene glycol with a maximum molecular weight of 2,000, preferably 1,000, particularly preferably 500. Reaction products of the aforementioned diols with ε-caprolactone or other lactones can also be used as diols.

2. Tri- and higher alcohols with a molecular weight between 92 and 254, such as glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol and sorbitol or polyethers with these alcohols as starter molecules, for example, 1 mol The reaction product of trimethylolpropane and 4mol ethylene oxide.

3. Monohydric alcohols, for example ethanol, 1- and 2-propanol, 1- and 2-butanol, 1-hexanol, 2-ethylhexanol, cyclohexanol and benzyl alcohol.

4. Dicarboxylic acids and/or their anhydrides with a molecular weight ranging from 104 to 600, for example, phthalic acid, phthalic anhydride, isophthalic acid, tetrahydrophthalic acid, tetrahydrophthalic acid Acid anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, cyclohexanedicarboxylic acid, maleic anhydride, fumaric acid, malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, heptane Diacids, suberic acid, sebacic acid, dodecanedioic acid and hydrogenated dimerized fatty acids.

5. Higher functionality carboxylic acids and their anhydrides, eg trimellitic acid and trimellitic anhydride.

6. Monocarboxylic acids, for example, benzoic acid, cyclohexanecarboxylic acid, 2-ethylhexanoic acid, caproic acid, caprylic acid, capric acid, lauric acid and naturally occurring and synthetic fatty acids.

7. Acrylic acid, methacrylic acid and dimerized acrylic acid.

Particularly preferred hydroxyl-containing polyester-acrylates comprise the reaction product of at least one component from class 1 or 2 with at least one component from class 4 or 5 and at least one component from class 7 .

It is also possible to incorporate groups which have a dispersing effect and are well known in the prior art into the polyester-acrylates used according to the invention, such as are described, for example, in Advances in Organic Coatings 9 (1981), 291-296. For example, a proportion of polyethylene glycol and/or methoxypolyethylene glycol can be incorporated as the alcohol component. Compounds which may be mentioned are, for example, polyethylene glycols and polypropylene glycols starting (polymerized) on alcohols and their block copolymers and the monomethyl ethers of these polyglycols. Preference is given to polyethylene glycol 1500 and/or polyethylene glycol 500 monomethyl ether.

It is additionally possible to react certain (excess) carboxyl groups, especially those of (meth)acrylic acid, with mono-, di- or polyepoxides. Preferred epoxides are monomeric, oligomeric or polymeric bisphenol A, bisphenol F, epoxides (glycidyl ethers) of hexanediol and/or butanediol. This reaction is particularly useful for increasing the hydroxyl number of polyester-acrylates, since hydroxyl groups are formed in each case in the epoxide-acid reaction.

The preparation of polyester-acrylates suitable for the present invention is described, for example, in DE-A-4 040 290, DE-A-3 316 592 and P.K.T. Oldring (ed.) "Chemistry and Craftsmanship, Volume 2, 1991 SITA Technology, London, p.123-135.

The acid value of the polyester-acrylate is less than or equal to 20mgKOH/g, preferably less than or equal to 10mgKOH/g, especially preferably less than or equal to 5mgKOH/g.

Alternatively, hydroxyl-group-containing epoxy acrylates, hydroxyl-group-containing polyether-acrylates or hydroxyl-group-containing polyurethane- Acrylates, their mixtures with each other and with unsaturated polyesters containing hydroxyl groups, also with polyester-acrylates, or with unsaturated polyesters containing hydroxyl groups and polyester-acrylic mixture of esters.

The polymers according to the invention therefore preferably contain (meth)acrylate double bonds in addition to the allyl double bonds present in the structural units of A1 and/or A2.

Compounds suitable as component (a3) are those which contain at least one group reactive with isocyanate groups and at least one ionic and/or potentially ionic group. Those groups which are capable of forming ionic groups are to be understood as potentially ionic groups. Ionic or potentially ionic groups are, for example, carboxyl, sulfonic acid, phosphoric acid or phosphonic acid groups or their corresponding anions. Carboxyl/carboxylate and/or sulfone/sulfonate groups are preferred. Suitable components (a3) are described, for example, in US-A 3,412,054, columns 1 and 2, US-A 3,640,924, column 3 and in DE-A 26 24 442, pp. 25-26, incorporated herein by reference.

Also suitable are amino group-containing compounds (a3), for example α,δ-diaminovaleric acid or 2,4-diamino-toluene-5-sulfonic acid. Mixtures of these compounds (a3) can also be used.

Especially preferred compounds (a3) are alcohols containing at least one carboxyl group, preferably 1 to 3 carboxyl groups per molecule. Examples of such compounds are hydroxyvaleric acid, dihydroxycarboxylic acids such as α,α-dihydroxyalkylalkanoic acids, especially α,α-dimethylolalkanoic acids, e.g., 2,2-dimethylol Acetic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid and 2,2-dimethylolvaleric acid, and dihydroxysuccinic acid, but also polyhydroxy acids such as glucose sugar acid. 2,2-Dimethylolpropionic acid is very particularly preferred.

The low molecular weight polyols and/or secondary polyamines (a4) optionally used to constitute the polymers of the invention generally have the effect of stiffening the polymer chains. They have a molecular weight of 62-400, preferably 62-200, and may contain aliphatic, cycloaliphatic or aromatic groups.

Suitable components (a4) that may be mentioned are low molecular weight polyols having up to about 20 carbon atoms per molecule, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1, 4-butanediol, 1,3-butanediol, cyclohexanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, bisphenol A (2,2-bis(4- Hydroxyphenyl)-propane), hydrogenated bisphenol A (2,2-bis(4-hydroxycyclohexyl)-propane) and aspartate, for example as described in EP-A 0 403 924, and mixtures thereof . Trihydric alcohols, such as trimethylolpropane and/or glycerol, may also be used in combination. Also suitable are polyols which comprise up to 5 epoxybutene units (A1/A2) whose polymerization starts on water, short-chain polyols or polyamines and which have an average molecular weight of less than 400.

The polymers according to the invention may optionally also contain units (a5) which in each case are at the chain end and block the chain end, so-called chain terminators.

Suitable components (a5) are derived from monofunctional compounds capable of reacting with NCO groups, for example monoamines, preferably mono-secondary amines, or monohydric alcohols. Examples that may be mentioned here are methylamine, ethylamine, propylamine, butylamine, octylamine, laurylamine, octadecylamine, isononyloxypropylamine, dimethylamine, diethylamine, dipropylamine, di Butylamine, N-methyl-aminopropylamine, diethyl(methyl)aminopropylamine, morpholine, piperidine or their substituted derivatives, amidoamines formed from di-primary amines and monocarboxylic acids, di-primary Monoketimines from amines and primary/tertiary amines, for example, N,N-dimethylaminopropylamine.

Monohydroxy-functional esters of acrylic acid and/or methacrylic acid, so-called (meth)acrylates, are also suitable as component (a5). Examples of such compounds are dihydric alcohols such as ethylene glycol, the various isomeric propylene glycols and the mono(meth)acrylates of butanediol, or polyhydric alcohols such as trimethylolpropane, glycerol and pentaerythritol (meth)acrylates, which contain an average of 1 free hydroxyl group.

Preferred compounds (a5) are those containing active hydrogens having different reactivity towards NCO groups. These, for example, contain secondary amino groups in addition to primary amino groups, or contain carboxyl groups in addition to hydroxyl groups, or contain hydroxyl groups in addition to amino groups (primary or secondary). compounds, preferably the latter. Examples of these compounds are primary/secondary amines such as 3-amino-1-methylamino-propane, 3-amino-1-ethylaminopropane, 3-amino-1-cyclohexylaminopropane, 3-amino-1- Methylaminobutane, monohydroxycarboxylic acids such as glycolic acid, lactic acid or malic acid, and other alkanolamines such as N-aminoethylethanolamine, ethanolamine, 3-aminopropanol, neopentanolamine, Particularly preferred is diethanolamine. Aspartate esters based on the abovementioned aminoalcohols, as mentioned, for example, in EP-A 0 743 333, are also suitable.

The polymers according to the invention may optionally also contain units (a6) derived from so-called chain extenders. Here, possible chain extenders are known compounds capable of reacting with NCO groups, and preferably difunctional compounds, which differ from (a2), (a3), (a4) and (a5) and generally have less than Average molecular weight of 400. Examples that may be mentioned here are water, hydrazine, adipic acid dihydrazide, poly(di)amines such as ethylenediamine, diethylenetriamine, dimethylethylenediamine, diaminopropane, Hexamethylenediamine, isophoronediamine and 4,4'-diaminodicyclohexylmethane, which may also carry substituents, for example hydroxyl groups, and mixtures of the compounds mentioned above. Such polyamines are disclosed, for example, in DE-A 36 44 371.

The preparation of the polymers according to the invention is described in the prior art, for example, in EP-A 0 355 682, EP-A 0 427 028 or DE-A 3 901 190.

Its preparation can be carried out, for example, according to a procedure in which first an isocyanate-functional prepolymer is prepared and in a second step by reaction with compounds (a5) and/or (a6) OH- and/or NH- Functional compounds, as disclosed, for example, in EP-A 0 355 682. However, its preparation can also be carried out by directly forming polyurethane resins containing hydroxyl groups by reaction between components (a1) to (a6), as described, for example, in EP-A 0 427 028.

The polymers A) according to the invention are preferably prepared according to a procedure in which initially components (a1, polyisocyanate), (a2, polyol) and optionally component (a4, low molecular weight polyol) and component (a3 ) preparing a polyurethane prepolymer containing on average at least 1.7, preferably 2 to 2.5 free isocyanate groups per molecule, which is then completely or partially mixed with components (a5) and/or (a6) in a non-aqueous system react.

The polyisocyanates are used in the process according to the invention in excess relative to the polyols (a2) to (a4), in order to obtain products with free isocyanate groups. These isocyanate groups are terminal and/or pendant, preferably terminal. Here, the amount of polyisocyanate is suitably high enough that the equivalent ratio of isocyanate groups to the total number of hydroxyl groups in polyols (a2) to (a4) is 1.05 to 2.0, preferably 1.1 to 1.6.

The preparation of the prepolymers is generally carried out at temperatures between 40° C. and 140° C., depending on the reactivity of the isocyanates used. The urethanization reaction can be accelerated using suitable catalysts such as those known to accelerate the NCO-OH reaction by those skilled in the art. Examples are tertiary amines, eg triethylamine, organic compounds such as dibutyltin oxide, dibutyltin dilaurate or tin bis(2-ethylhexanoate) or other organometallic compounds.

The urethanization reaction is preferably carried out in the presence of a solvent inert to isocyanates. Those solvents which are compatible with water, for example, ethers, ketones and esters and N-methylpyrrolidone may be particularly suitable for this purpose. The amount of the solvent used should not exceed 25% by weight, preferably 5-15% by weight, in each case based on the total weight of the polyurethane resin and the solvent. Here, the polyisocyanate in solution can be quickly added to a solution of other components.

Subsequently, the prepolymer or its solution is reacted with the compound (a5) and/or (a6) of the present invention, during which the temperature is preferably 0°C to 90°C, preferably 20°C to 60°C, until the NCO content of the prepolymer decreases to actually zero. For this purpose, compound (a5) is used in an amount less than or slightly in excess of the stoichiometric amount, generally between 40 and 110 wt%, preferably 60 to 105 wt%, of the required stoichiometric amount. If less reactive diisocyanates are used to prepare the prepolymers, the reaction can also be carried out in water simultaneously with the neutralization. Some of the (unneutralized) COOH groups, preferably 5 to 30% by weight, may optionally be reacted with difunctional compounds reactive with COOH groups, such as diethoxy compounds.

Alternatively, before the dispersing operation, a certain proportion (based on the isocyanate content) of the prepolymer can also react with (a5), and then after the dispersing operation, all or part of the remaining isocyanate groups are then reacted with component (a6) react. Here, the neutralization of the carboxyl groups can be carried out either before dispersion by adding a neutralizing agent to the prepolymer or during the dispersion operation by adding a neutralizing amine to the dispersion water.

The polymers A) according to the invention can also be prepared according to a procedure for the direct reaction of components (a1) to (a6) to give hydroxyl-functional resins. The reaction conditions here correspond to those described for the preparation of prepolymers containing NCO groups. Such methods are described, for example, in EP-A 0 427 028.

Another possible preparation of the polyurethane polymers according to the invention consists in making a compound containing COOH and/or SO ₃ H groups and additionally containing one or more isocyanate-reactive groups via di- and/or polyisocyanates. Resins, reacted with polyether-alcohols containing at least a proportion of repeating units A1 and/or A2. Resins suitable for this method are for example vinyl polymers, polyesters, epoxides or hybrid resins (eg acrylate-grafted polyesters or polyurethanes), such as those known in the prior art.

Tertiary amines, e.g. trialkylamines, having 1 to 12, preferably 1 to 6 carbon atoms per alkyl group, are particularly suitable for neutralizing the obtained products containing COOH and/or _SO3H groups . Examples are trimethylamine, triethylamine, methyldiethylamine, tripropylamine and diisopropylethylamine. These alkyl groups may also carry, for example, hydroxyl groups, such as in the case of dialkyl-alkanol-, alkyldialkanol- and trialkanolamines, such as dimethylethanolamine, Preferably used as a neutralizing agent. Inorganic bases, such as ammonia or sodium or potassium hydroxide, may also optionally be used as neutralizing agents. The amount of the neutralizing agent is in the range of 0.3:1 to 1.3:1, preferably 0.5:1 to 1:1, based on the molar ratio of the neutralizing agent to the acid groups of the prepolymer.

Neutralization of the COOH or SO ₃ H groups can take place before, during or after the urethanization reaction. The neutralization reaction is usually carried out between room temperature and 100°C, preferably between 40°C and 80°C. Here, the neutralization can be carried out in any desired manner, for example, adding an aqueous neutralizing agent to the polyurethane resin or vice versa. However, it is also possible to first add the neutralizing agent to the polyurethane resin and only then to add water. In general, a solids content of 20 to 70 wt%, preferably 30 to 50 wt%, is obtained in this way.

The present invention also provides an aqueous dispersion comprising:

A) 20 to 70% by weight, preferably 25 to 50% by weight of at least one water-dilutable polymer containing urethane groups according to the invention,

B) 0-20 wt%, preferably 0-10 wt% organic co-solvent, and

C) 10-70 wt%, preferably 30-60 wt% water.

Mixtures of several inventive polymers (A) can also be used.

Suitable organic co-solvents (B) are conventional lacquer solvents known per se, for example ethyl acetate, butyl acetate, ethylene glycol monomethyl- or -ethyl-ether-acetate, 1-methoxy Propyl 2-acetate, 3-methoxy-n-butyl acetate, acetone, 2-butanone, 4-methyl-2-pentanone, cyclohexanone, toluene, xylene, chlorine Benzene, white spirit, containing, mainly, mixtures of more highly substituted aromatics, for example, under the trade names solvent naphtha, ^Solvesso® (ExxonMobil Chemical Company, Houston), ^Cypar® (Shell Chemical Company, UK), ^CycloSol® ( Shell Chemical Company), Tolu ^Sol® (Shell Chemical Company) and ^Shellsol® (Shell Chemical Company), carbonates such as dimethyl carbonate, diethyl carbonate, ethylene carbonate and carbonic acid 1,2-Propylene, lactones such as β-propiolactone, γ-butyrolactone, ε-caprolactone and ε-methylcaprolactone, and also solvents such as diacetate of propylene glycol, diacetate Glyme dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol ethyl and butyl ether-acetates, N-methylpyrrolidone and N-methylcaprolactam, or any desired mixture of such solvents.

The organic cosolvents (B) can be added to the water-dispersible polymers according to the invention containing urethane groups or dispersions thereof after or during preparation. At least some organic solvent may be added in a conventional manner during the preparation or dispersion of the polymers of the present invention. To prepare low-cosolvent-content or cosolvent-free dispersions, it is also possible to employ a cosolvent during the preparation process but to remove it again in a later step.

In application as coating compositions, the dispersions containing the water-dispersible polymers containing urethane groups according to the invention are used either alone or in combination with other aqueous binders. Such aqueous binders can consist, for example, of polyester, polyacrylate, polyepoxide or polyurethane polymers. Combinations with radiation-curing binders, such as those described in EP-A-0 753 531, are also possible. The dispersions containing the polymers according to the invention can be used as such or in combination with auxiliary substances and additives known from paint technology, such as complex pigments, paint and paint auxiliaries, such as anti-sedimentation agents, defoamers and/or Wetting agents, flow control agents, reactive diluents, plasticizers, catalysts, co-solvents or thickeners for the production of coatings.

The present invention also provides a coating composition comprising a water-dispersible polymer according to the invention containing urethane groups.

The dispersions containing the polymers according to the invention are used as binders for the production of paints. Such coatings can be used to coat any desired substrates, for example wood, metal, plastics, paper, leather, textiles, felt, glass or mineral substances.

Preference is given to producing an oxidative-drying aqueous coating, characterized in that the coating composition comprises as binder the water-reducible polymers (A) according to the invention containing urethane groups.

Driers may be added to accelerate oxidative crosslinking.

The advantage of the dispersions containing the polymers (A) according to the invention is that they enable the production of fast-drying coatings without the addition of driers.

Preference is also given to formulation UV-curing coatings, characterized in that the coating composition contains as binder a water-dilutable, urethane-group-containing polymer (A) according to the invention, and one or more photoinitiator.

The UV-curing coatings produced in this way are distinguished by a particularly good shadow-curing capability compared to prior art UV-curing lacquers. In the coating of especially shaped structures, unlike lamellar structures, the problem often occurs that UV-cured coatings are too soft, tacky and / or lack of tolerance. Post-curing by a second mechanism independent of UV light presents advantages here.

Suitable photoinitiators are, for example, aromatic ketone compounds such as benzophenones, alkylbenzophenones, 4,4'-bis(dimethylamino)benzophenone (Michler's ketone), anthrone and halogenated diphenyl ketone. Acylphosphine oxides, such as 2,4,6-trimethyl-benzoyl-diphenylphosphine oxide, phenyl diglycolate, anthraquinone and its derivatives, benzoyl ketal and benzene Hydroxyalkyl ketones are also suitable. Mixtures of these compounds may also be used.

The coating compositions comprising the polymers (A) according to the invention can be applied in a known manner, for example by spreading, pouring, knife coating, spraying, atomizing spray, swirl-coating, rolling or dipping. The drying of the paint film can be carried out at room temperature or at elevated temperature, or by baking at a temperature up to 200°C. Preferably drying is performed at room temperature or only slightly above room temperature. If the dispersion according to the invention comprises UV-curable components, the drying method may additionally comprise irradiation with UV light.

During drying of the coating, water and, if used, other solvents are preferably first driven out of the coating by known methods, followed by UV irradiation and finally oxidative-drying.

The present invention also relates to substrates coated with coating compositions comprising the water-reducible polymers (A) according to the invention containing urethane groups.

Detailed ways

example

All percentage data are percentages by weight.

Example 1 (the present invention)

1,022 g of isophthalic acid, 6,900 g of soy fatty acid, 1,278 g of benzoic acid, 3,353 g of pentaerythritol, and 911 g of phthalic anhydride were weighed into a 15 L reaction vessel with agitator, heating, and water separator with cooling , and then heated to 140° C. under nitrogen over a period of 1 h. The mixture was further heated to 220° C. during the next 8 h, whereupon the condensation reaction was carried out at this temperature until the acid number reached a level of less than 3. The viscosity of the polyester resin thus obtained (determined according to the flow time of a solution of 75% polyester in xylene in a DIN 4 cup at 23° C.) was 105 s, and its hydroxyl number was 175 mg KOH/g.

607g of the above-described polyester was first introduced into a 4L reaction vessel with cooling, heating and stirring devices, and mixed with 58g of dimethylolpropionic acid, 150g of 3,4-epoxy-1-butene in 3,4 -Dihydroxyl-1-butene is used as a linear polyether diol with a hydroxyl value of 75mgKOH/g, 75g of N-methylpyrrolidone, 75g of dipropylene glycol dimethyl ether and 22g of triamine prepared by the ring-opening polymerization of the initiator molecule. to 80 °C, then the mixture was homogenized for 30 min. Subsequently, 185 g of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI) was added under vigorous stirring, and the mixture was heated to 100° C. heat) and maintained at this temperature until no more NCO groups are picked out.

The linear polyether diol was obtained by adding 37g (0.42mol) 3,4-dihydroxy-1-butene, 600g 3,4-epoxy-1-butene and 1mL trimethyl orthobenzoate at 120°C. A solution of the trimethylorthobenzoate was added to a solution of 50 g of a DMC catalyst prepared according to EP-A 0 700 049 in 5 mL of toluene. The rate of addition is chosen so that the reaction temperature does not exceed 155°C. Then the reaction temperature was maintained at 150° C. until all the 3,4-epoxy-1-butene was reacted. The molecular weight of the product, determined using GPC (Gel Permeation Chromatography), is equal to 2074 mol, and the polydispersity M _w /M _n =1.15.

Subsequently, the product was dispersed with 1,000 g of distilled water at 95°C and the viscosity was adjusted to 930 mPa.s (D=40s ^-1 , 23°C) with water and triethylamine.

The aqueous, urethane-modified polyester resin thus obtained had an acid value of 26 mg KOH/g, an average particle size of 150 nm and a solids content of 45.6%.

Example 2 (the present invention)

607 g of polyester from Example 1 were first introduced into a 4 L reaction vessel with cooling, heating and stirring devices, and mixed with 58 g of dimethylolpropionic acid, 150 g of 3,4-epoxy-1-butene and epoxy Propane (molar ratio 50:50) using tripropylene glycol as the initiator molecule to prepare linear polyether diol with a hydroxyl value of 73 mg KOH/g and a number average molecular weight of 1,300, 150 g of N-methylpyrrolidone and 22 g of triethylamine Heat together to 80°C and then homogenize the mixture for 30min. Subsequently, 185 g of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI) were added under vigorous stirring, and the mixture was heated to a maximum of 100° C. Exothermic) and maintained at this temperature until no more NCO groups are picked out.

The linear polyether diol was prepared according to Example 1, except that the reaction of catalyst, starter molecule, propylene oxide and 3,4-epoxy-1-butene was carried out in an autoclave.

Subsequently, the product was dispersed with 1,000 g of distilled water at 95°C and the viscosity was adjusted to 640 mPa.s (D=40s ^-1 , 23°C) with water and triethylamine.

The aqueous, urethane-modified polyester resin thus obtained had an acid value of 26 mg KOH/g, an average particle size of 170 nm and a solids content of 45.8%.

Example 3 (the present invention)

612 g of polyester from Example 1 were first introduced into a 4 L reaction vessel with cooling, heating and stirring devices, and mixed with 58 g of dimethylolpropionic acid, 150 g of 3,4-epoxy-1-butene and ring A mixture of propylene oxide (molar ratio 50:50) and propylene oxide polyether is a linear polyether triol with a hydroxyl value of 56 mg KOH/g and a number average molecular weight of 4,200 prepared by ring-opening polymerization of glycerin with a hydroxyl value of 238 as the initiator , 150g N-methylpyrrolidone and 22g triethylamine were heated together to 80°C, and then the mixture was homogenized for 30min. Subsequently, 180 g of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI) was added under vigorous stirring, and the mixture was heated to 100° C. heat) and maintained at this temperature until no more NCO groups are picked out.

The linear polyether diol was prepared according to Example 1, except that the reaction of catalyst, starter molecule, propylene oxide and 3,4-epoxy-1-butene was carried out in an autoclave.

Subsequently, the product was dispersed with 1,000 g of distilled water at 95°C and the viscosity was adjusted to 1,070 mPa.s (D=40s ^-1 , 23°C) with water and triethylamine.

The aqueous, urethane-modified polyester resin thus obtained had an acid value of 27 mg KOH/g, an average particle size of 200 nm and a solids content of 46.1%.

Example 4 (the present invention)

602 g of polyester from Example 1 were first introduced into a 4 L reaction vessel with cooling, heating and stirring devices, and mixed with 58 g of dimethylolpropionic acid, 150 g of the linear polyester with a hydroxyl value of 75 mg KOH/g used in Example 1 Ether diol, 150g N-methylpyrrolidone and 22g triethylamine were heated together to 80°C, and then the mixture was homogenized for 30min. Subsequently, 190 g of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI) was added under vigorous stirring, and the mixture was heated to 100° C. heat) and maintained at this temperature until no more NCO groups are picked out.

Subsequently, the product was dispersed with 1,000 g of distilled water at 95°C and the viscosity was adjusted to 620 mPa.s (D=40s ^-1 , 23°C) with water and triethylamine.

The aqueous, urethane-modified polyester resin thus obtained had an acid value of 26 mg KOH/g, an average particle size of 240 nm and a solids content of 45.7%.

Example 5 (the present invention)

1,347 g trimethylolpropane, 5,631 g soy fatty acid, 3,722 g phthalic anhydride, and 2,614 g neopentyl glycol were weighed into a 15 L reaction vessel with agitator, heating, and water separator with cooling , then heated up to 140° C. under nitrogen over a period of 1 h. The mixture was heated further to a maximum of 220° C. during the next 8 h, at which temperature the condensation reaction was then carried out until the acid number reached a level of less than 3. The viscosity of the polyester resin thus obtained (determined according to the flow time of a solution of 80% polyester in xylene in a DIN 4 cup at 23° C.) was 59 s, and its hydroxyl value was 46 mg KOH/g.

1,410g of the above-described polyester precursor was first introduced into a 4L reaction vessel with cooling, heating and stirring devices, and mixed with 151g of dimethylolpropionic acid, 390g of the linear compound described in Example 1 with a hydroxyl value of 75mgKOH/g Polyether diol and 650g N-methylpyrrolidone were heated together to 100°C, and then the mixture was homogenized for 30min. Subsequently, it was cooled to 70°C, and 650 g of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI) was added under vigorous stirring, and the reaction mixture This temperature was maintained under stirring until the NCO content reached 2.5% (about 10-15 h). Then 114 g of triethylamine were homogeneously stirred into it.

In a 6L reaction vessel with cooling, heating and stirring devices, 2,080g of the NCO prepolymer thus obtained heated to 55°C was introduced into 1,395g of distilled water preheated to 30°C under stirring within 5 to 10 minutes middle. The mixing temperature was controlled at about 40°C. The crude dispersion was cooled to about 30° C. and then a solution of 36.4 g of ethylenediamine in 815 g of distilled water was added with stirring. Subsequently, the mixture was stirred at 35~40°C for another 2 h, and then the viscosity was adjusted to 2,300 mPa.s (D=40s ^-1 , 23°C) with water and triethylamine.

The polyurethane dispersion thus obtained had an acid number (100%) of 25 mg KOH/g, an average particle size of 42 nm and a solids content of 37.2%.

Example 6 (comparative example)

Preparation of Fatty Acid-Based Urethane-Modified Polyester Dispersions

1,126 g of the polyester precursor described in Example 1 was first introduced into a 4 L reaction vessel with cooling, heating and stirring devices, and mixed with 87.5 g of dimethylolpropionic acid, 244 g of N-methylpyrrolidone and 33 g of triethylamine Heat together to 80°C and then homogenize the mixture for 30min. Subsequently, 286.5 g of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI) was added under vigorous stirring, and the mixture was heated to 100° C. Exothermic) and maintained at this temperature until no more NCO groups are picked out.

Subsequently, 14.4 g of ethoxylated nonylphenol were added and the mixture was dispersed into 1,400 g of water, homogenized and the viscosity adjusted to 1,100 mPa.s (D=40 s ⁻¹ , 23° C.) with water and triethylamine. The aqueous, urethane-modified polyester resin thus obtained had an acid value of 27 mg KOH/g and a solids content of 45%.

Application example 1 (oxidation-drying topcoat):

^{Octasoligen®} Co 7 aqua (cobalt drier, 50% aqueous solution, Borchers company) is equivalent to the Co metal concentration of 0.06%, is based on solid resin (base material 100%), is added to examples 1～5 and comparative example 6 The mixture was diluted with water to a flow time of about 30 s (DIN 4 cups, 23° C.) and applied with a doctor blade to a degreased glass plate or degreased steel plate (dry film layer thickness 50 μm). After drying at room temperature, a defect-free paint film with a good level of performance is obtained.

Performance of the dispersion application example 1 oxidation-drying paint based on examples 1 to 6: Dispersions from the following examples Gloss 20° dry Xylene Resistant ^* Pendulum hardness 2d/14d RT Water resistance wrinkle (8/24h) Resistance to water tarnish ^* (3/8/24h) 1 80 7h 2 24/76s iO/iO 0/2/4 2 77 8 hours 2 18/46s iO/iO 0/2-3/5 3 74 8 hours 2 16/54s iO/iO 0/3/5 4 71 7h 2 31/95s iO/iO 0/0/3 5 75 7h 2 21/35s iO/iO 0/1/4 6 (comparative example) 78 8 hours 2 26/59s wrinkled/heavily wrinkled 2/4/5

*: possible rating from 0 to 5; 0 = no damaged membrane, 5 = very severely damaged membrane

Table 1 shows that the dispersions prepared according to Examples 1-5 of the present invention have improved water resistance. In the case of Comparative Example 6, it was found that after only 3 h a significant gloss loss occurred, and after 8 h a slight wrinkling of the paint film, and after 24 h a severe wrinkling which was irreversible. On the other hand, the paints based on Examples 1 to 5 show clearly better results.

Example 7 (the present invention)

163.8 g of the linear polyether diol described in Example 1 with a hydroxyl value of 75 mg KOH/g, 181 g of poly(1,4-butylene glycol ether) with a hydroxyl value of 56 mg KOH/g, 37.2 g of dimethylol propionic acid, 18.3 g 1,6-Hexanediol and 97.4g N-methylpyrrolidone are mixed with each other in a 2L four-necked flask with stirring device, reflux condenser and internal thermometer, the mixture is heated to 70°C, and then 275.5g ^Desmodur® W ( Bayer (Leverkusen)). The temperature was maintained at 80°C, then, when the NCO content of the prepolymer reached 4.4%, the temperature was lowered to 70°C, and 19.6 g of triethylamine were added. After 10 min, 500 g of prepolymer were transferred within 5 min to a second 2 L flask equipped with a stirrer and filled with 670 g of water (20° C.). After vigorous stirring for 10 min, a mixture of 5.2 g of hydrazine hydrate, 8.4 g of ethylenediamine and 74.4 g of water was added within 5 min. The mixture was then stirred at 40° C. until no more NCO was picked up in the dispersion. The polyurethane dispersion had an average particle size of 69 nm and a solids content of 35.3%.

A varnish comprising 87.9% of the polyurethane dispersion, 3.0% butylene glycol, 1.0% Byk® ⁰²⁸ (defoamer, Byk Chemical Company, Wesel), 0.2% Byk® ⁰²⁴ (defoamer, Byk), 0.2% Byk® ³⁴⁶ (substrate wetting additive, Byk), 0.5% ^Byk® 381 (flow additive, Byk), 0.2% ^TS® 100 (matting agent, Degussa company, Frankfurt), 2.0% Aquamat® ²⁶³ (wax/slip Additive, Byk) and 2.0% ^Acrysol® RM 8 (5%, thickener, Rohm & Haas, Philadelphia) were knife coated onto glass plates with a doctor blade with a gap width of 200 μm and dried at room temperature for 7 days. A transparent, glossy paint film with a pendulum hardness (14 days at room temperature) of 115 s was obtained.

Example 8 (the present invention)

163.8 g of the linear polyether diol described in Example 2 with a hydroxyl value of 73 mg KOH/g, 181 g of poly(1,4-butylene glycol ether) with a hydroxyl value of 56 mg KOH/g, 37.2 g of dimethylol propionic acid, 18.3 g 1,6-Hexanediol and 97.4g N-methylpyrrolidone are mixed with each other in a 2L four-necked flask with stirring device, reflux condenser and internal thermometer, the mixture is heated to 70°C, and then 275.5g Desmodur® ^W is added rapidly (by Bayer (Leverkusen)). The temperature was maintained at 80°C, then, when the NCO content of the prepolymer reached 4.4%, the temperature was lowered to 70°C, and 19.6 g of triethylamine were added. After 10 min, 500 g of prepolymer were transferred within 5 min to a second 2 L flask equipped with a stirrer and filled with 670 g of water (20° C.). After vigorous stirring for 10 min, a mixture of 5.2 g of hydrazine hydrate, 8.4 g of ethylenediamine and 74.4 g of water was added within 5 min. The mixture was then stirred at 40° C. until no more NCO was picked up in the dispersion. The polyurethane dispersion had an average particle size of 70 nm and a solids content of 35.3%.

A varnish comprising 87.9% of the polyurethane dispersion, 3.0% butylene glycol, 1.0% Byk® ⁰²⁸ (defoamer, Byk), 0.2% Byk® ⁰²⁴ (defoamer, Byk), 0.2% ^Byk® 346 ( Substrate wetting additive, Byk), 0.5% ^Byk® 381 (flow additive, Byk), 0.2% ^TS® 100 (matting agent, Degussa company), 2.0% Aquamat® ²⁶³ (wax/slip additive, Byk) and 2.0% % ^Acrysol® RM 8 (5%, thickener, Rohm & Haas), was knife coated onto a glass plate with a doctor blade with a gap width of 200 μm and dried at room temperature for 7 days. A transparent, glossy paint film with a pendulum hardness (14 days at room temperature) of 80 s was obtained.

Example 9

Oligomer precursor for example 10

3,200 g castor oil and 1,600 g soybean oil and 2.4 g dibutyltin oxide were weighed into a 5 L reactor with distillation attachment. A nitrogen stream (5 l/h) was passed through the reactants. The mixture was heated to 240°C within 140 min. After 7 h at 240 °C, the mixture was cooled. The hydroxyl value is 109 mg KOH/g, and the acid value is 2.5 mg KOH/g.

Example 10 (comparative example):

Preparation of Fatty Acid Based Polyurethane Dispersion

339 g poly-1,4-butylene glycol ether with a hydroxyl value of 56 mg KOH/g, 248 g polyester oligomer precursor, 70 g dimethylolpropionic acid, 34 g 1,6-hexanediol and 34 g N-methylpyrrolidone Heating to 70°C, the mixture was stirred until a clear solution formed. Subsequently, 516 g of ^Desmodur® W (Bayer AG, Leverkusen) were added and the mixture was heated to 100°C. It was stirred at this temperature until the NCO content reached 4.1%. Subsequently, it was cooled to 70° C., and 52.6 g of triethylamine were added.

650 g of this solution were dispersed under vigorous stirring in 601 g of water, which was initially introduced at a temperature of 30°C. After the dispersing operation, the mixture was stirred for 5 min. Subsequently, a solution of 3.9 g of hydrazine hydrate and 10.2 g of ethylenediamine in 200 g of water was added within 5 min. To complete the reaction of the isocyanate groups, the mixture was stirred at 45°C until no more NCO groups were picked out.

The polyurethane dispersion thus prepared had an average particle size of 60 nm and a solids content of 35%.

A varnish comprising 87.9% of the polyurethane dispersion, 3.0% butylene glycol, 1.0% Byk® ⁰²⁸ (defoamer, Byk), 0.2% Byk® ⁰²⁴ (defoamer, Byk), 0.2% ^Byk® 346 ( Substrate wetting additive, Byk), 0.5% ^Byk® 381 (flow additive, Byk), 0.2% ^TS® 100 (matting agent, Degussa company), 2.0% Aquamat® ²⁶³ (wax/slip additive, Byk) and 2.0% % ^Acrysol® RM 8 (5%, thickener, Rohm & Haas), was knife coated onto a glass plate with a doctor blade with a gap width of 200 μm and dried at room temperature for 7 days. A transparent, glossy paint film with a pendulum hardness (14 days at room temperature) of 75 s was obtained.

Example 11 (the present invention)

UV-curing and oxidation-drying dispersions

313.0 g of polyester-acrylate ^Larmomer® PE44F (polyester-acrylate; BASF Corporation, Ludwigshafen, DE) with a hydroxyl content of about 80 mg KOH/g and 87.7 g of polyether diol from Example 1, 21.0 g of dimethylol Propionic acid, 0.5 g of dibutyltin dilaurate and 172.2 g of acetone were first introduced into a 2 L reaction vessel with stirrer, internal thermometer and gas inlet (2-3 l/h air flow), followed by 79.9 g of Desmodur® ^I (isophorone diisocyanate; Bayer AG, Leverkusen, DE) and 39.4 g of ^Desmodur® H (hexamethylene diisocyanate; Bayer AG, Leverkusen, DE) and the mixture was heated until a constant acetone reflux was obtained. The reaction mixture was stirred at this temperature until it contained an NCO content of 1.6% by weight. Then, it was cooled to 40°C, and 15.8 g of triethylamine was added rapidly. After 10 min, the reaction mixture was poured into 938.1 g of water at 18° C. with vigorous stirring. When a dispersion had formed, a solution of 8.0 g ethylenediamine in 23.5 g water was added. After the mixture was stirred for 30 min without heating or cooling, the product was subjected to vacuum distillation (50 mbar, max. 50° C.) until a solids content of 38.6 wt. % was reached. The viscosity of the dispersion was 24.7 s in a DIN 4 cup, its pH was determined to be 8.6 and the average particle size according to laser correlation spectroscopy (Zetasizer 1000, Malvern Instruments, Malvern, UK) was 60.0 nm.

Application example 12

1.5 wt% of Irgacure( ^R) 500 (photoinitiator, Ciba Specialty Chemicals, Lampertheim, DE), based on the solids content of the dispersion, was stirred into one portion of the inventive dispersion of Example 11. After the dispersion had stood overnight, it was drawn down onto a glass plate using a doctor blade with an opening width of 150 μm. The coated glass plates were kept at room temperature for 40 min. Forms a clear, transparent and dry film. Subsequently, the coated glass plate was passed under a medium-pressure mercury lamp (output 80 W/cm lamp length) at a speed of 5 m/min. The paint film UV-cured in this way exhibited a König pendulum hardness of 59 after 30 min of irradiation. During 36h at room temperature, the hardness of the pendulum increased to 82.

Claims (16)

1. A water-dilutable polymer comprising urethane groups and having ionic and/or potential ionic groups, characterized in that the polymer comprises repeating units (A1) of general formula (I) and/or Repeating unit (A2) of formula (II) 2. The water-dilutable polymer according to claim 1, characterized in that the repeat units A1, A2 or mixtures of A1/A2 are present in the polymer as blocks

form or in the form of a mixed block of two structural units with p repeating units, wherein n, m and p each represent an integer from 3 to 100. 3. The water dilutable polymer according to claim 1 or 2, characterized in that the polymer is a reaction product comprising the following components: (a1) 5-80wt% polyisocyanate, (a2) 10-80% by weight of polyols and/or polyamines whose average molecular weight _Mn is at least 400, (a3) 2 to 15% by weight of compounds containing at least one group reactive with isocyanate groups and at least one ionic and/or potentially ionic group, (a4) 0～20wt% low molecular weight polyol and/or secondary polyamine, (a5) 0～20wt% chain terminator, (a6) 0 to 20% by weight of a chain extender which contains at least two groups reactive with isocyanate groups and is different from (a2), (a3) and (a4). 4. The water-dispersible polymer according to claim 1, characterized in that it additionally comprises C═C double bonds in the structural units of mono- or polyunsaturated fatty acids. 5. The water-dispersible polymer according to claim 1, characterized in that it additionally comprises a C=C double bond in the acrylic and or methacrylate units A3 of the general formula (III),

6. The water-dilutable polymer according to one or more of claims 1 to 5, characterized in that the polymer has a content of ionic and/or potentially ionic groups of 9 to 100 meq/100 g. 7. The water-dilutable polymer according to one or more of claims 1 to 6, characterized in that the ionic and/or potentially ionic groups are carboxyl and/or sulfonic acid groups. 8. The water-dilutable polymer according to one or more of claims 1 to 7, characterized in that the polymer has a content of urethane groups [NHCOO] of 1 to 40% by weight. 9. The water-dilutable polymer according to one or more of claims 1 to 8, characterized in that the polymer has a content of structural units A1 and/or A2 of 2 to 80% by weight. 10. An aqueous dispersion comprising: A) 20 to 70% by weight of at least one water-reducible polymer containing urethane groups according to claim 1, B) 0～20wt% organic co-solvent, and C) 10-70wt% water. 11. A coating composition comprising the urethane group-containing water-reducible polymer of claim 1. 12. A process for producing an oxidation-drying paint, characterized in that the paint composition comprises the urethane group-containing water-reducible polymer according to claim 1 as a binder. 13. A method for producing a UV-curable coating, characterized in that the coating composition comprises the urethane group-containing water-reducible polymer according to claim 1 as a binder, and one or more photoinitiators. 14. Use of the water-dilutable polymers containing urethane groups according to claim 1 for the production of oxidation-drying coatings. 15. Use of the water-dilutable polymer containing urethane groups according to claim 1 for the production of UV-curable coatings. 16. A substrate coated with a coating composition comprising the urethane group-containing water-reducible polymer of claim 1.