EP1597295A1 - Single-component coating systems - Google Patents

Abstract

The invention relates to aqueous single-component (1K) coating systems based on polyurethane dispersions which do not react with isocyanate groups and blocked, hydrophobic polyisocyanates, in addition to a method for the production and use thereof.

Description

One-component coating systems

The invention relates to aqueous one-component (IC) coating systems based on polyurethane dispersions which are not reactive toward isocyanate groups and blocked, hydrophobic polyisocyanates, and to a process for their preparation and use.

When coating substrates, solvent-based binders are increasingly being replaced by aqueous, environmentally friendly systems. In particular, binders based on polyurethane-polyurea dispersions play an increasing role due to their excellent properties.

The production of aqueous polyurethane (PUR) dispersions is generally known. The various possibilities for producing such dispersions have been described e.g. by D. Dieterich

.. * t described in a review article (D. Dieterich, Prog. Org. Coatings 9, 281 (1981)).

In order to further improve certain properties of these dispersions, they are often used in combination with crosslinking agents based on blocked polyisocyanates.

For example, O-A 02/14395 discloses the preparation of coating compositions which are composed of polyols containing urethane groups and hydrophobic polyisocyanates blocked with pyrazole derivatives. The thermally induced deblocking leads to the crosslinking of polyol and polyisocyanate with the formation of urethane. The resulting coatings are suitable for stone chip-resistant, non-yellowing coatings.

IC coating systems based on PUR dispersions, which have blocked isocyanate groups and no significant amounts of groups reactive towards isocyanates, can be crosslinked under thermal stress with the substrate on which they are applied or into which they have been incorporated.

In many areas of application e.g. in the sizing of glass fibers or the production of glass fiber reinforced plastics, polyurethane-polyurea dispersions which have no groups reactive towards isocyanates are therefore used in combination with blocked water-dispersible or water-soluble blocked polyisocyanates, the production of which is described, for example, in DE-A 24 56469 and DE-A 28 53 937 is used.

With the aqueous one-component (IC) coating compositions known from the prior art, however, the high requirements, in particular in properties such as water resistance and wet adhesion, are not satisfactorily achieved. The object of the present invention was therefore to provide aqueous storage-stable coating systems which, compared to conventional coating agents of the prior art, have a higher water resistance and wet grip after the filming.

It has been found that hydrophobic, blocked polyisocyanates can be dispersed stably in water with the aid of water-dispersible or water-soluble polyurethanes, which have no significant amounts of Zerewitinoff-active hydrogen atoms, and the properties of the coating produced therefrom, such as water resistance and wet adhesion significantly improve. The water-dispersible or water-soluble polyurethanes fulfill the task of an “emulsifier” for the blocked polyisocyanates. Since the polyurethanes do not have any significant amount of Zerewitinoff-active hydrogen atoms, they do not form a self-wetting dispersion in combination with the blocked polyisocyanates. After the blocking agent has been split off at an elevated temperature crosslink the functional groups of the polyisocyanate crosslinker with the isocyanate-reactive groups of the substrate on which the coating agent was applied In contrast to conventional binder-Z crosslinker combinations in which the binder and crosslinker are hydrophilized, the coating agents according to the invention have a much lower total hydrophilicity, from which Application to a substrate, significantly lower water absorption, higher water resistance and better wet adhesion of the coating result.

The invention relates to aqueous one-component (IC) coating systems containing

(I) at least one polyurethane (A), which contains chemically bound hydrophilic groups and a content of groups containing Zerewitinoff-active hydrogen atoms of 0 to 0.53 mmol / g, preferably 0 to 0.4 mmol / g, particularly preferred from 0 to 0.25 mmol / g, based on the nonvolatile content of the dispersion, and

(II) at least one polyisocyanate (B) in which the NCO groups are reversibly blocked and which contains no hydrophilic groups and

(m) water,

in which. the quantitative ratio of components (A) and (B) is such that the blocked isocyanate content is between 0.01 and 1.0 mol / 100 g of solid resin.

For the purposes of the present invention, groups with Zerewitinoff-active H atoms are hydroxyl, primary or secondary amine or thiol groups. In the context of the present invention, ionic or nonionic groups are grouped under hydrophilic groups.

The polyurethanes (A) suitable for the IC coating systems according to the invention are reaction products from

AI) polyisocyanates,

A2) polymeric polyols and / or polyamines with average molecular weights of 400 to 8000,

A3) optionally mono- or polyalcohols or mono- or polyamines or amino alcohols with molecular weights up to 400,

and at least one connection selected from

A4) Compounds which have at least one ionic or potentially ionic group and / or

A5) nonionically hydrophilized compounds.

For the purposes of the invention, a potentially ionic group is a group which is capable of forming an ionic group.

The polyurethanes (A) are preferably prepared from 7 to 45% by weight of AI), 50 to 91% by weight of A2), 0 to 15% by weight of A5), 0 to 12% by weight of ionic or potentially ionic Compounds A4) and optionally 0 to 30% by weight of compounds A3), the sum of A4) and A5) being 0.1 to 27% by weight and the sum of the components adding up to 100% by weight.

The polyurethanes (A) are particularly preferably composed of 10 to 30% by weight of AI), 65 to 90% by weight of A2), 0 to 10% by weight of A5), 3 to 9% by weight of ionic or potential Ionic compounds A4) and optionally 0 to 10% by weight of compounds A3), the sum of A4) and A5) being 0.1 to 19% by weight and the sum of the components adding up to 100% by weight ,

The polyurethanes (A) are very particularly preferably prepared from 8 to 27% by weight of AI), 65 to 85% by weight of A2), 0 to 8% by weight of A5), 3 to 8% by weight of ionic or potentially ionic compounds A4) and optionally 0 to 8% by weight of compounds A3), the sum of A4) and A5) being 0.1 to 16% by weight and the sum of the components being 100% by weight add. Suitable polyisocyanates (AI) are aromatic, araliphatic, aliphatic or cycloaliphatic polyisocyanates. Mixtures of such polyisocyanates can also be used. Examples of suitable polyisocyanates are butylene diisocyanate, hexamethylene diisocyanate (BDI), isophorone diisocyanate (IPDI), 2,2,4 and / or 2,4,4-trimethylhexamethylene diisocyanate, the isomeric bis (4,4'-isocyanatocyclohexyl) methanes or their mixtures of any isomer content, Isocyanatomethyl-l, 8-octane diisocyanate, 1,4-cyclohexylene diisocyanate, 1,4-phenylene diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, 2,4'- or 4,4 '-Diphenylmethane diisocyanate, triphenylmethane-4,4', 4 "triisocyanate or their derivatives with urethane, isocyanurate, allophanate, biuret, uretdione, iminooxadiazinedione structure and mixtures thereof. Preferred are hexamethylene diisocyanate, isophorone diisocyanate and the isomeric bis (4,4'-isocyanatocyclohexyl) methanes and mixtures thereof.

These are preferably polyisocyanates or polyisocyanate mixtures of the type mentioned with exclusively aliphatic and / or cycloaliphatic isocyanate groups. Very particularly preferred starting components (AI) are polyisocyanates or polyisocyanate mixtures based on HDI, IPDI and / or 4,4'-diisocyanatodicyclohexylmethane.

Also suitable as polyisocyanates (AI) are any polyisocyanates made from at least two diisocyanates with uretdione, isocyanurate, urethane, allophanate, biuret, iminooxadiazinedione, which are prepared by modifying simple aliphatic, cycloaliphatic, araliphatic and / or aromatic diisocyanates - and / or oxadiazinetrione structure, as described, for example, in J. Prakt. Chem. 336 (1994) pp. 185-200.

Suitable polymeric polyols or polyamines (A2) have an OH functionality of at least 1.5 to 4, such as, for example, polyacrylates, polyesters, polylactones, polyethers, polycarbonates, polyester carbonates, polyacetals, polyolefins and polysiloxanes. Polyols in a molecular weight range from 600 to 2500 with an OH functionality of 2 to 3 are preferred.

The polycarbonates containing hydroxyl groups are obtainable by reacting carbonic acid derivatives, for example diphenyl carbonate, dimethyl carbonate or phosgene, with diols. Examples of such diols are ethylene glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentylglycol, 1,4-bishydroxymethylcyclohexane, 2 - Methyl-l, 3-propanediol, 2,2,4-trimethylpentanediol-1,3, dipropylene glycol, polypropylene glycols, dibutylene glycol, polybutylene glycols, bisphenol A, tetrabromobisphenol A but also lactone-modified diols in question. The diol component preferably contains 40 to 100% by weight of hexanediol, preferably 1,6-hexanediol and / or hexanediol derivatives, preferably those which contain ether or ester groups in addition to terminal OH groups, for example products which Reaction of 1 mole of hexanediol with at least 1 mole, preferably 1 to 2 moles of caprolactone according to DE-A 17 70 245 or by etherification of hexanediol with themselves to give di- or trihexylene glycol. The preparation of such derivatives is known, for example, from DE-A 15 70 540. The polyether polycarbonate diols described in DE-A 37 17 060 can also be used.

The hydroxyl polycarbonates should preferably be linear. However, if necessary, they can easily be branched by incorporating polyfunctional components, in particular low molecular weight polyols. Glycerol, trimethylolpropane, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylolpropane, pentaerythritol, quinite, mannitol, and sorbitol, methylglycoside, 1,3,4,6-dianhydrohexite are suitable for this purpose.

Suitable polyether polyols are the polytetra methylene glycol polyethers known per se in polyurethane chemistry, which e.g. can be prepared via polymerization of tetrahydrofuran by cationic ring opening.

Other suitable polyether polyols are polyethers such as e.g. the polyols made from styrene oxide, propylene oxide, butylene oxides or epichlorohydrin, in particular propylene oxide, produced using starter molecules.

Suitable polyester polyols are e.g. Reaction products of polyhydric, preferably dihydric and optionally additionally trihydric alcohols with polyhydric, preferably dibasic carboxylic acids. Instead of the free polycarboxylic acids, the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof can also be used to produce the polyesters. The polycarboxylic acids can be aliphatic, cycloaliphatic, aromatic and / or heterocyclic in nature and optionally, e.g. be substituted by halogen atoms and / or unsaturated.

Components (A3) are suitable for terminating the polyurethane prepolymer. To . monofunctional alcohols and monoamines can be used. Preferred monoalcohols are aliphatic monoalcohols having 1 to 18 carbon atoms, such as ethanol, n-butanol, ethylene glycol monobutyl ether, 2-ethylhexanol, 1-octanol, 1-dodecanol or 1-hexadecanol. Preferred monoamines are aliphatic monoamines, such as diethylamine, dibutylamine, ethanolamine, N-methyl ethanolamine or N, N-diethanolamine and amines of the Jeffamin ^® M series (Huntsman Corp. Europe, Belgium) or amino-functional polyethylene oxides and polypropylene oxides.

Also suitable as component (A3) are polyols, aminopolyols or polyamines with a molecular weight below 400, which are described in large numbers in the corresponding literature. Preferred components (A3) are, for example:

a) Alkanediols or triols, such as ethanediol, 1,2- and 1,3-propanediol, 1,4- and 2,3-butanediol, 1,5-pentanediol, 1,3-dimethylpropanediol, 1,6-hexanediol , Neopentyl glycol, 1,4-cyclohexanedimethanol, 2-methyl-l, 3-propanediol, 2-ethyl-2-butylpropanediol, trimethylpentanediol, positionally isomeric diethyloctanediols, 1,2- and 1,4-cyclohexanediol, hydrogenated

Bisphenol A [2,2-bis (4-hydroxycyclohexyl) propane], 2,2-dimethyl-3-hydroxypropionic acid (2,2-dimethyl-3-hydroxypropyl ester), trimethylolethane, trimethylol propane or glycerol,

b) ether diols, such as diethylene diglycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butylene glycol or hydroquinone dihydroxyethyl ether,

c) ester diols of the general formulas (I) and (II),

HO- (CH ₂ ) χ-CO-0- (CH ₂ ) _y -OH (I),

HO- (CH ₂ ) _x -0-CO-R-CO-0 (CH ₂ ) _x -OH (II),

in which

R is an alkylene or arylene radical with 1 to 10 C atoms, preferably 2 to 6 C atoms,

x 2 to 6 and

y is 3 to 5,

such as. δ-hydroxybutyl-ε-hydroxy-caproic acid ester, ω-hydroxyhexyl-γ-hydroxybutter acid ester, adipic acid (ß-hydroxyethyl) ester and terephthalic acid bis (ß-hydroxy-ethyl) ester and

d) di- and polyamines such as 1,2-diaminoethane, 1,3-diaminopropane, 1,6-diaminohexane, 1,3- and 1,4-phenylenediamine, 4,4'-diphenylmethane diamine, isophoronediamine, mixture of isomers of 2, 2,4- and 2,4,4-trimethylhexa-methylenediamine, 2-methyl-pentamethylenediamine, diethylenetriamine, 1,3- and 1,4-xylylenediamine, α, α, α ', α'-tetramethyl- 1,3- and 1,4-xylylenediamine, 4,4-ethylene oxides Diammodicyclohexylmethan, amino-functional poly- or polypropylene oxides, which under the name Jeffamine ^® D series (Fa. Huntsman Corp. Europe, Belgium) are available, diethylenetriamine, and Triethylene tetramine. Hydrazine, hydrazine hydrate and substituted hydrazines, such as, for example, N-methylhydrazine, N, N'-dimethylhydrazine and, are also suitable as diamines in the context of the invention their homologues as well as acid dihydrazides, adipic acid, ß-methyladipic acid, sebacic acid, hydracrylic acid and terephthalic acid, semicarbazido-alkylene hydrazides, such as, for example, ß-semicarbazidopropionic acid hydrazide (described, for example, in DE-A 1770 591), semicarbazido, such as 2-carbazines Semicarbazidoethylcarbazine esters (for example described in DE-A 19 18 504) or aminosemicarbazide compounds such as, for example, β-aminoethylsemicarbazido carbonate (for example described in DE-A 19 02 931).

Component (A4) contains ionic groups, which can be either cationic or anionic in nature. Cationic, anionically dispersing compounds are those which contain, for example, sulfonium, ammonium, phosphonium, carboxylate, sulfonate, phosphonate groups or the groups which can be converted into the aforementioned groups by salt formation (potentially ionic groups) can be built into the macromolecules by existing isocyanate-reactive groups. Suitable isocyanate-reactive groups are preferably hydroxyl and amine groups.

Suitable ionic or potentially ionic compounds (A4) are, for example, mono- and dihydroxycarboxylic acids, mono- and diaminocarboxylic acids, mono- and dihydroxysulfonic acids, mono- and diaminosulfonic acids as well as mono- and dihydroxyphosphonic acids or mono- and diaminophosphonic acids and their salts such as dimethylolpropionic acid, Dimethylolbutyric acid, hydroxypivalic acid, N- (2-aminoethyl) -ß-alanine, 2- (2-amino-ethylamino) -ethanesulfonic acid, ethylenediamine-propyl- or butylsulfonic acid, 1,2- or 1,3-propylenediamine-β-ethylsulfonic acid , Malic acid, citric acid, glycolic acid, lactic acid, glycine, alanine, taurine, lysine, 3,5-diamino-benzoic acid, an addition product of IPDI and acrylic acid (EP-A 0 916 647, example 1) and its alkali and / or ammonium salts ; the adduct of sodium bisulfite with butene-2-diol-1,4, polyether sulfonate, the propoxylated adduct of 2-butenediol and NaHS0 ₃ , for example described in DE-A 2446 440 (page 5-9, formula I-III) and in Building blocks which can be converted into cationic groups such as N-methyl-diethanolamine as hydrophilic structural components. Preferred ionic or potentially ionic compounds are those which have carboxy or carboxylate and / or sulfonate groups and / or ammonium groups. Particularly preferred ionic compounds are those which contain carboxyl and / or sulfonate groups as ionic or potentially ionic groups, such as the salts of N- (2-aminoethyl) -ß-alanine, 2- (2-aminoethylamino) ethanesulfonic acid or the addition product of IPDI and acrylic acid (EP-A 0 916 647, Example 1) and dimethylolpropionic acid.

Suitable nonionically hydrophilizing compounds (A5) are, for example, polyoxyalkylene ethers which contain at least one hydroxyl or amino group. These polyethers contain from 30% by weight to 100% by weight of building blocks which are derived from ethylene oxide. In The question is linearly structured polyethers with a functionality between 1 and 3, but also compounds of the general formula (III),

in which

R ¹ and R ² each independently represent a divalent aliphatic, cycloaliphatic or aromatic radical having 1 to 18 carbon atoms, which can be interrupted by oxygen and / or nitrogen atoms, and

R ^{3 represents} an alkoxy-terminated polyethylene oxide radical.

Compounds which have a nonionic hydrophilicity are, for example, monovalent polyalkylene oxide polyether alcohols having a statistical average of 5 to 70, preferably 7 to 55, ethylene oxide units per molecule, as are obtainable in a manner known per se by alkoxylation of suitable starter molecules (for example in Ullmanns Encyclopedia of Industrial Chemistry, 4. Edition, volume 19, Verlag Chemie, Weinheim pp. 31-38).

Suitable starter molecules are, for example, saturated monoalcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, the isomeric pentanols, hexanols,

Octanols and nonanols, n-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol,

Cyclohexanol, the isomeric methylcyclohexanols or hydroxymethylcyclohexane, 3-ethyl-3-hydroxymethyloxetane or tetrahydrofuran alcohol, diethylene glycol monoalkyl ether such as, for example, diethylene glycol monobutyl ether, unsaturated alcohols such as allyl alcohol, 1,1-dimethyl allyl alcohols, phenol or olefin alcohols, or alcohol alcohols Methoxyphenols, araliphatic alcohols such as benzyl alcohol, anise alcohol or cinnamon alcohol, secondary monoamines such as dimethylamine, diethylamine, dipropylamine, diisopropylamine,

Dibutylamine, bis (2-ethylhexyl) amine, N-methyl and N-ethylcyclohexylamine or

Dicyclohexylamine and heterocyclic secondary amines such as morpholine, pyrrolidine, piperidine or lH-Pyrazόl. Preferred starter molecules are saturated monoalcohols. Diethylene glycol monobutyl ether is particularly preferably used as the starter molecule.

Alkylene oxides suitable for the alkoxylation reaction are, in particular, ethylene oxide and propylene oxide, which can be used in the alkoxylation reaction in any order or in a mixture. The polyalkylene oxide polyether alcohols are either pure polyethylene oxide polyethers or mixed polyalkylene oxide polyethers whose alkylene oxide units consist of at least 30 mol%, preferably at least 40 mol%, of ethylene oxide units. Preferred nonionic compounds are monofunctional mixed polyalkylene oxide polyethers which have at least 40 mol% of ethylene oxide and at most 60 mol% of propylene oxide units.

A combination of nonionic (A4) and ionic (A5) hydrophilizing agents is preferably used to produce the polyurethane (A). Combinations of nonionic and anionic hydrophilizing agents are particularly preferred.

The aqueous polyurethane (A) can be prepared in one or more stages in a homogeneous or, in the case of a multi-stage reaction, in some cases in the disperse phase. After the polyaddition has been carried out in full or in part, a dispersing, emulsifying or dissolving step is carried out. This may be followed by a further polyaddition or modification in the disperse phase.

All processes known from the prior art, such as emulsifier-shear force, acetone, prepolymer mixing, melt-emulsifying, ketimine and solid-spontaneous dispersion processes, or descendants thereof, can be used to produce the polyurethane (A) become. A summary of these methods can be found in methods of organic chemistry (Houben-Weyl, extension and follow-up volumes to the 4th edition, volume E20, H. Bartl and J. Falbe, Stuttgart, New York, Thieme 1987, pp. 1671 - 1682) , The melt-emulsifying, prepolymer mixing and acetone processes are preferred. The acetone process is particularly preferred.

Usually, the components (A2) to (A5), which have no primary or secondary amino groups, and a polyisocyanate (AI) for the preparation of a polyurethane prepolymer are introduced in whole or in part in the reactor and, if appropriate, with a water-miscible but inert to isocyanate groups diluted, but preferably without solvent, heated to higher temperatures, preferably in the range from 50 to 120 ° C.

Suitable solvents are, for example, acetone, butanone, tetrahydrofuran, dioxane, acetonitrile, dipropylene glycol dimethyl ether and l-methyl-2-pyrrolidone, which can be added not only at the start of the preparation but also, if appropriate, in part later. Acetone and butanone are preferred. It is possible to carry out the reaction under normal pressure or elevated pressure, for example above the normal pressure boiling point of a solvent such as, for example, acetone. Furthermore, the catalysts known to accelerate the isocyanate addition reaction, such as, for example, triethylamine, 1,4-diazabicyclo [2,2,2] octane, dibutyltin oxide, tin dioctoate or dibutyltin dilaurate, tin bis (2-ethylhexanoate) or other organometallic compounds presented or added later. Dibutyltin dilaurate is preferred.

Subsequently, the constituents (AI), (A2), optionally (A3) and (A4) and / or (A5) which do not have any primary or secondary amino groups which have not yet been added at the start of the reaction are added. In the production of the polyurethane prepolymer, the molar ratio of isocyanate groups to groups reactive with isocyanate is 0.90 to 3, preferably 0.95 to 2.5, particularly preferably 1.05 to 2.0. The reaction of components (AI) to (A5) is based on the total amount of isocyanate-reactive groups in the part of (A2) to (A5) which has no primary or secondary amino groups, partially or completely, but preferably completely. The degree of conversion is usually monitored by monitoring the NCO content of the reaction mixture. Spectroscopic measurements, e.g. Infrared or near-infrared spectra, determinations of the refractive index as well as chemical analyzes, such as titrations, of samples taken can be carried out. Polyurethane prepolymers containing free isocyanate groups are obtained in bulk or in solution.

After or during the preparation of the polyurethane prepolymers from (AI) and (A2) to (A5), if this has not yet been carried out in the starting molecules, the partial or complete salt formation of the anionically and or cationically dispersing groups takes place. In the case of anionic groups, bases such as ammonia, ammonium carbonate or hydrogen carbonate, trimethylamine, triethylamine, tributylamine, diisopropylethylamine, dimethylethanolamine, diethylethanolamine, triethanolamine, potassium hydroxide or sodium carbonate are used, preferably triethylamine, triethanolamine, dimethylethanolamine or diisopropylethylamine. The amount of the bases is between 50 and 100%, preferably between 60 and 90% of the amount of the anionic groups. In the case of cationic groups, dimethyl sulfate or succinic acid are used. If only non-ionically hydrophilized compounds (A5) with ether groups are used, the neutralization step is omitted. The neutralization can also take place at the same time as the dispersion, in which the dispersing water already contains the neutralizing agent.

Possible amine components are (A2), (A3) and (A4) with which any remaining isocyanate groups can be reacted. This chain extension can be done either in solvent before dispersing, during dispersing or in water after the dispersion can be carried out. If aminic components are used as (A4), the chain extension is preferably carried out before the dispersion.

The amine component (A2), (A3) or (A4) can be added to the reaction mixture diluted with organic solvents and / or with water. 70 to 95% by weight of solvent and / or water are preferably used. If several amine components are present, the reaction can be carried out in succession in any order or at the same time by adding a mixture.

For the preparation of the polyurethane dispersion (A), the polyurethane prepolymers, optionally with strong shear, such as vigorous stirring, either introduced into the dispersing water or, conversely, the dispersing water is stirred into the prepolymers. Then, if it has not yet occurred in the homogeneous phase, the molar mass can be increased by reaction of any isocyanate groups which may be present with component (A2), (A3). The amount of polyamine (A2), (A3) used depends on the unreacted isocyanate groups still present. 50 to 100%, particularly preferably 75 to 95% of the amount of the isocyanate groups are preferably reacted with polyamines (A2), (A3).

If necessary, the organic solvent can be distilled off. The dispersions have a solids content of 10 to 70% by weight, preferably 25 to 65% by weight and particularly preferably 30 to 60% by weight.

Suitable blocked polyisocyanates (B) are obtained by reacting

(B1) at least one polyisocyanate with aliphatic, cycloaliphatic, araliphatic and / or aromatically bound isocyanate groups, which has no hydrophilic groups with

(B2) at least one blocking agent

manufactured.

The blocked polyisocyanates (B) can optionally contain solvents (B3).

Suitable polyisocyanates (B1) for producing the blocked polyisocyanates (B) are, by modifying simple aliphatic, cycloaliphatic, araliphatic and / or aromatic diisocyanates, polyisocyanates composed of at least two diisocyanates with uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and or Oxadiazinetrione structure obtained- Lich, as for example in J. Prakt. Chem. 336 (1994) page 185-200 are described by way of example.

Suitable diisocyanates for the preparation of the polyisocyanates (B1) are diisocyanates of the molecular weight range 140 to 400 accessible by phosgenation or by phosgene-free processes, for example by thermal urethane cleavage, with aliphatic, cycloaliphatic, araliphatic and / or aromatically bound isocyanate groups, such as e.g. 1,4-diisocyanatobutane, 1,6-diisocyanatohexane (BDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- and 2,4 , 4-trimethyl-l, 6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,3- and l, 4-bis- (isocyanatomethyl) -cyclohexane, l-isocyanato-3 , 3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 4,4'-diisocyanatodicyclohexylmethane, l-isocyanato-l-methyl-4 (3) isocyanato-methylcyclohexane, bis- (isocyanatomethyl) - norbornane, 1 , 3- and l, 4-bis- (2-isocyanato-prop-2-yl) -benzene (TMXDI), 2,4- and 2,6-duesocyanatotoluene (TDI), 2,4'- and 4 , 4'-diisocyanatodiphenylmethane, 1,5-diisocyanatonaphthalene or any mixture of such diisocyanates.

Triisocyanates such as triphenylmethane-4,4 ', 4 "-triisocyanate and / or 4-isocyanatomethyl-1,8-octane diisocyanate are also suitable.

The starting components (B1) are preferably polyisocyanates or polyisocyanate mixtures of the type mentioned with exclusively aliphatic and / or cycloaliphatic isocyanate groups.

Particularly preferred starting components (B1) are polyisocyanates or polyisocyanate mixtures with isocyanurate and / or biuret structure based on HDI, IPDI and / or 4,4'-diisocyanatodicyclohexylmethane.

The polyisocyanates (B1) have an NCO content of 1% to 50%, preferably 8% to 25%. If appropriate, they can be diluted with a water-miscible solvent which is inert to isocyanates.

The polyisocyanates (B1) used to prepare the blocked polyisocyanates (B) have an (average) NCO functionality of 2.0 to 5.0, preferably 2.3 to 4.5, and an isocyanate group content of 1.0 to 50.0% by weight, preferably from 5.0 to 27.0% by weight and particularly preferably 5.0 to 27.0% by weight from 14.0 to 24.0% by weight and a content of monomeric diisocyanates of less than 1% by weight, preferably less than 0.5% by weight. Examples of blocking agents (B2) include alcohols, lactams, oximes, malonic esters, alkylacetoacetates, triazoles, phenols, imidazoles, pyrazoles and amines such as butanone oxime, diisopropylamine, 1,2,4-triazole, dimethyl-l, 2,4 triazole, imidazole, diethyl malonate, acetoacetic ester, acetone oxime, ε-caprolactam, N-tert-butyl-benzylamine, 3,5-dimethylpyrazole, or pyrazole derivatives of the general formula (IV),

in which

R ¹ corresponds to one or more (cyclo) aliphatic hydrocarbon radicals each having 1 to 12, preferably 1 to 4, carbon atoms and which does not contain any chemically bound hydrophilic groups

n can be an integer from 0 to 3, preferably 1 or 2,

or any mixtures of these blocking agents.

Butanone oxime, compounds of the formula (TV), ε-caprolactam, N-tert-butylbenzylamine are preferably used as blocking agents (B2). A particularly preferred blocking agent (B2) is 3,5-dimethylpyrazole or 3-methylpyrazole.

Suitable organic solvents (B3) are the conventional paint solvents, such as, for example, ethyl acetate, butyl acetate, 1-methoxypropyl-2-acetate, 3-methoxy-n-butyl acetate, acetone, 2-butanone, 4-methyl-2-pentanone, Cyclohexanone, toluene, xylene, chlorobenzene or white spirit. Mixtures containing mainly highly substituted aromatics such as, for example under the designations Solvent Naphtha, Solvesso ^® (Exxon Chemicals, Houston, USA), Cypar ^® (Shell Chemicals, Eschborn, DE), Cyclo Sol ^® (Shell Chemicals Eschborn, DE), Tolu Sol ^® (Shell Chemicals, Eschborn, DE), Shellsol ^® (Shell Chemicals, Eschborn, DE) are commercially available, are also suitable. Other solvents are, for example, carbonic acid esters such as dimethyl carbonate, diethyl carbonate, 1,2-ethylene carbonate and 1,2-propylene carbonate, lactones such as ß-propiolactone, γ-butyrolactone, ε-caprolactone, ε-methylcaprolactone, propylene glycol diacetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, Diethylene glycol ethyl and butyl ether acetate, N-methylpyrrolidone and N-methylcaprolactam or any mixture of such solvents. Preferred solvents are acetone, 2-butanone, 1-methoxypropyl-2-acetate, xylene, toluene, mixtures which contain above all more highly substituted aromatics, as described, for example, under the names Solvent Naphtha, Solvesso ^® (Exxon Chemicals, Houston, USA), Cypar ^® (Shell Chemicals, Eschborn, DE), Cyclo Sol ^® (Shell Chemicals, Eschborn, DE), Tolu Sol ^® (Shell Chemicals, Eschborn, DE) , Shellsol ^® (Shell Chemicals, Eschborn, DE) are commercially available, and N-methylpyrrolidone. Acetone, 2-butanone and N-methylpyrrolidone are particularly preferred.

The blocked polyisocyanates (B) are prepared by methods known in the art and are e.g. in EP-A 0159117 (pages 9-11).

The present invention also relates to a process for the preparation of the aqueous (IC) coating systems according to the invention, characterized in that the crosslinker component (B) is mixed with the polyurethane (A) before or during its transfer into the aqueous phase.

In a preferred embodiment, components (B) are mixed with component (A) before being transferred to the aqueous phase, and the mixture thus obtained is then dispersed in water. The polyurethane (A) then serves as an emulsifier for the non-hydrophilically modified crosslinker (B) and keeps it stable in the aqueous dispersion. If necessary, a chain extension step with component (A3) and / or (A4) can also be carried out in the aqueous dispersion.

The coating systems according to the invention can be used alone or with the binders, auxiliaries and tensile agents known in coating technology, in particular light stabilizers such as UV absorbers and sterically hindered amines (HALS), antioxidants, fillers and paint auxiliaries, e.g. Anti-settling agents, defoaming and / or wetting agents, leveling agents, reactive thinners, plasticizers, catalysts, auxiliary solvents and / or thickeners and additives, such as, for example, dispersions, pigments, dyes or matting agents, are used. In particular, combinations with other binders such as polyurethane dispersions or polyacrylate dispersions, which may also be hydroxy-functional, are possible without any problems. The additives can be added to the coating system according to the invention immediately before processing. However, it is also possible to add at least some of the additives before or during the dispersion of the binder or binder / crosslinker mixture. The selection and the dosage of these substances, which can be added to the individual components and / or the total mixture, are known to the person skilled in the art.

After removal of the water, the coating compositions according to the invention produce dust-dry to hard and mechanically resilient coatings even without the addition of auxiliaries. The The water can be removed by evaporation or forced drying, preferably up to 100 ° C., for example by exposure to heat, warm and / or dehumidified air and / or heat radiation. Subsequent thermally induced crosslinking between 100 and 200.degree. C., preferably between 110 and 180.degree. C., which may also be carried out with the substrate on which the coating was applied, cures the films to give particularly high-quality, water and hydrolysis-resistant coatings or lacquer coatings ,

The present application also relates to a method for producing coatings, characterized in that the aqueous coating system according to the invention is applied to a substrate, the water is at least partially removed and then thermally cured.

The coating compositions according to the invention can be applied to a wide variety of substrates using customary techniques, for example by spraying, rolling, knife coating, pouring, spraying, brushing or dipping. Substrates are selected from the group of wood, metal, plastic, paper, leather, textiles, felt, glass or mineral substrates. Preferred substrates are glass or carbon fibers.

Substrates coated with the (IC) coating systems according to the invention are also the subject of the present invention.

The applied layer thicknesses (before curing) are typically between 0.05 and 5000 μm, preferably between 0.05 and 1500 μm, particularly preferably between 0.05 and 1000 μm.

The invention also relates to the use of the aqueous (1-component) coating systems according to the invention in adhesives, sealants and lacquers and sizes, use in or as sizes, preferably glass fiber sizes, is preferred.

The (IC) coating compositions according to the invention are used as binder components for the production of the sizing agents and can contain further components such as emulsifiers, further film-forming resins, adhesion promoters, lubricants and auxiliaries such as wetting agents or antistatic agents. The adhesion promoters, lubricants and auxiliary substances, the process for the production of the sizing agents and the process for the sizing of glass fibers and the postprocessing of the glass fibers are known and are described, for example, in KL Loewenstein "The Manufacturing Technology of Continous Glass Fibers", Elsevier Scientific Publishing Corp., Amsterdam , London, New York, 1983. Examples

Products used:

Desmodur W: 4,4'-diisocyanatodicyclohexylmethane, Bayer AG, Leverkusen, DE

Desmodur I: isophorone diisocyanate, Bayer AG, Leverkusen, DE

Desmodur H: 1,6-hexamethylene diisocyanate, Bayer AG, Leverkusen, DE

Desmodur ^® N3200: biuret group-containing polyisocyanate based on 1,6-di-isocyanatohexane (HDI) with an NCO content of 23.0%, Bayer AG, Leverkusen, DE

Desmodur ^® N3300: polyisocyanate containing isocyanurate groups and based on 1,6-diisocyanate hexane (HDI) with an NCO content of 21.8%, Bayer AG, Leverkusen, DE

Desmodur ^® VPLS 2376: polyisocyanate containing isocyanurate groups and based on 1,6-diisocyanate hexane (BDI) blocked with 3,5-dimethylpyrazole (80% in methyl ethyl ketone), Bayer AG, Leverkusen, DE

Desmorapid SO: Tin-2-ethylhexanoate, Bayer AG, Leverkusen, DE

AAS: 45% aqueous solution of the sodium salt of 2- (2-aminoethylamino) ethanesulfonic acid, Bayer AG, Leverkusen, DE

Irganox® 245 ethylene bis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], Ciba Spezialitaten GmbH, Lampertheim, DE)

The mechanical properties of the binding agents or coating agents are determined on free films which are produced as follows:

A release paper is placed in front of the rear roller in a film puller, consisting of two polished rollers that can be set to an exact distance. The distance between the paper and the front roller is set with a feeler gauge. This distance corresponds to the film thickness (wet) of the resulting coating and can be adjusted to the desired level of each stroke. Coating can also be carried out consecutively in several strokes. To apply the individual coats, the products (aqueous formulations are previously adjusted to a viscosity of by adding ammonia / polyacrylic acid 4500 Pa s) poured onto the gap between the paper and the front roller, the release paper is pulled vertically downwards, whereby the corresponding film is formed on the paper. If several strokes are to be applied, each individual stroke is dried and the paper is reinserted.

The 100% modulus was determined in accordance with DIN 53504 on films larger than 100 μm thick.

The film is stored under hydrolysis conditions in accordance with DIN EN 12280-3. The mechanics of these film samples are determined after storage for 24 hours under standard climatic conditions (20 ° C. and 65% atmospheric humidity) in accordance with DIN 53504.

The mechanical film properties are determined after drying at 150 ° C. for 30 minutes.

Blocked polyisocyanates;

Example 1:

212.3 g Desmodur ^® N3300 are initially charged with 130.5 g methyl ethyl ketone and heated to 70 ° C. 179.3 g of N-tert-butylbenzylamine are then added dropwise with stirring over the course of 2 h and the reaction mixture is stirred at 70 ° C. until free isocyanate can no longer be detected by means of infrared spectroscopy.

Example 2:

249.5 g Desmodur ^® N3300 are initially charged with 125.0 g acetone. 125.5 g of 3,5-dimethylpyrazole are then added dropwise with stirring over the course of 2 hours, and the reaction mixture is stirred at 20 ° C. until no free isocyanate can be detected by means of infrared spectroscopy.

Example 3;

270.2 g Desmodur ^® N3300 are initially charged with 130.7 g methyl ethyl ketone and heated to 75 ° C. 121.8 g of butanone oxime are then added dropwise with stirring over the course of 2 hours, and the reaction mixture is stirred at 75 ° C. until free isocyanate can no longer be detected by means of infrared spectroscopy. dispersions:

Example 4:

169.9 g of the polyester PE 170 HN (Bayer AG, Leverkusen, DE, polyester based on adipic acid, neopentyl glycol and hexanediol with an average molecular weight of 1700 (OHZ = 66)) and 77.8 g of polyether LB 25 (Bayer AG, Leverkusen, DE, monofunctional polyether based on ethylene oxide-propylene oxide with an average molecular weight of 2250 (OHZ = 25)) are introduced and heated to 70 ° C. 50.9 g of Desmodur® W are then added over the course of 5 minutes at 20 ° C. with stirring, the reaction mixture is heated to 100 ° C. and stirred at this temperature until the theoretical NCO value (2.17%) is reached. After cooling to 50 ° C., the prepolymer is dissolved within 5 minutes by adding 128.0 g of acetone. After 156.5 g of the blocked polyisocyanate from Example 2 have been added, the reaction mixture is stirred for a further 5 minutes. The dispersion is carried out by adding 553.8 g of water (20 ° C.) within 10 minutes. Immediately after dispersion, a solution of 1.0 g of hydrazine monohydrate, 6.8 g of isophoronediamine and 41.8 g of water is metered in at 40 ° C. within 5 minutes. The stirring time at 40 ° C is 15 min. After removal of the solvent in vacuo, a storage-stable aqueous PU / crosslinker dispersion is obtained which has blocked isocyanate groups and has a solids content of 40.6%. The average particle size of the dispersion particles is 164 nm.

Example 5:

169.9 g of the polyester PE 170 HN (Bayer AG, Leverkusen, DE, polyester based on adipic acid, neopentyl glycol and hexanediol with an average molecular weight of 1700 (OHZ = 66)) and 77.8 g of polyether LB 25 (Bayer AG, Leverkusen, DE, monofunctional polyether based on ethylene oxide-propylene oxide with an average molecular weight of 2250 (OHZ = 25)) are introduced and heated to 70.degree. 50.9 g of Desmodur® W are then added over the course of 5 minutes at 20 ° C. with stirring, the reaction mixture is heated to 100 ° C. and stirred at this temperature until the theoretical NCO value (2.17%) is reached. After cooling to 50 ° C., the prepolymer is dissolved within 5 minutes by adding 128.0 g of acetone. After 156.5 g of the blocked polyisocyanate Desmodur® VPLS 2376 have been added, the reaction mixture is stirred for a further 5 min. The dispersion is carried out by adding 553.8 g of water (20 ° C.) within 10 minutes. Immediately after dispersion, a solution of 1.0 g of hydrazine monohydrate, 6.8 g of isophoronediamine and 41.8 g of water is metered in at 40 ° C. within 5 minutes. The stirring time at 40 ° C is 15 min. After removal of the solvent in vacuo, a storage-stable aqueous PU / crosslinker dispersion is obtained, which is blocked Has isocyanate groups, with a solids content of 40.2%. The average particle size of the dispersion particles is 266 nm.

Example 6

111.6 g of the Desmophen® 3900 polyether (Bayer AG, Lev., DE, trihydroxyfunctional based on propylene oxide and ethylene oxide with an average molecular weight of 4800 (OHZ = 35)), 11.9 g of polyether LB 25 (Bayer AG, Lev ., DE, monofunctional polyether based on ethylene oxide / propylene oxide with an average molecular weight of 2250 (OHZ = 25)) and 12.8 g of polyether sulfonate are introduced and heated to 70.degree. Then 18.7 g Desmodur® I, 14.2 g Desmodur® H and 0.1 g Desmorapid® SO are added within 5 min at 70 ° C with stirring. The reaction mixture is stirred at 70 ° C. until the theoretical NCO value (5.00%) is reached. After cooling to 50 ° C., the prepolymer is dissolved within 5 minutes by adding 314.1 g of acetone. After 177.2 g of the blocked polyisocyanate from Example 2 and 5.0 g of Irganox® 245 have been added, the reaction mixture is stirred for a further 10 min. The dispersion is carried out by adding 489.4 g of water (20 ° C.) within 5 minutes. Immediately after dispersion, a solution of 2.5 g of hydrazine monohydrate, 8.4 g of isophoronediamine and 205.2 g of water is metered in at 40 ° C. within 5 minutes. The stirring time at 40 ° C is 15 min. After removal of the solvent in vacuo, a storage-stable aqueous PU / crosslinking dispersion is obtained which has blocked isocyanate groups and a solids content of 30.1%. The average particle size of the dispersion particles is 314 nm.

Example 7

240.0 g of the polyester PE 170 HN (Bayer AG, Lev., DE, polyester based on adipic acid, neopentyl glycol and hexanediol with an average molecular weight of 1700 (OHZ = 66)) and 8.1 g of polyether LB 25 (Bayer AG , Leverkusen, DE, monofunctional polyether based on ethylene oxide / propylene oxide with an average molecular weight of 2250 (OHZ = 25)) are introduced and heated to 65 ° C. Subsequently, 35.6 g of Desmodur I and 26.9 g of Desmodur ^® H added within 5 min at 6 ° C with stirring, the reaction mixture is heated to 110 ° C and stirred at this temperature until the theoretical NCO value (4 , 8%) is reached. After cooling to 50 ° C., the prepolymer is dissolved within 5 minutes by adding 552.0 g of acetone. After adding 180.0 g of the blocked polyisocyanate Desmodur® VPLS 2376, the reaction mixture is stirred for a further 5 min. Before the dispersion, a solution of 20.9 g of isophoronediamine and 37.1 g of acetone is added at 40 ° C. within 2 minutes and then a solution of 6.9 g of AAS, 0.7 g of hydrazine monohydrate and 36 within 5 minutes , 2 g of water are metered in. The stirring time at 40 ° C is 15 min. The dispersion is carried out by adding 619.6 g Water (20 ° C) within 35 min. After removal of the solvent in vacuo, a storage-stable aqueous PU / crosslinker dispersion is obtained which has blocked isocyanate groups and has a solids content of 40.6%. The average particle size of the dispersion particles is 254 nm.

Example 8

169.9 g of the polyester PE 170 HN (Bayer AG, Lev., DE, polyester based on adipic acid, neopentyl glycol and hexanediol with an average molecular weight of 1700 (OHZ = 66)) and 77.8 g of polyether LB 25 (Bayer AG , Leverkusen, DE, monofunctional polyether based on ethylene oxide / propylene oxide with an average molecular weight of 2250 (OHZ = 25)) are introduced and heated to 70.degree. 50.9 g of Desmodur® W are then added over the course of 5 minutes at 20 ° C. with stirring, the reaction mixture is heated to 100 ° C. and stirred at this temperature until the theoretical NCO value (2.17%) is reached. After cooling to 50 ° C., the prepolymer is dissolved within 5 minutes by adding 128.0 g of acetone. After adding 145.9 g of the blocked polyisocyanate from Example 3, the reaction mixture is stirred for a further 5 min. The dispersion is carried out by adding 544.6 g of water (20 ° C.) within 10 minutes. Immediately after dispersion, a solution of 1.0 g of hydrazine monohydrate, 6.8 g of isophoronediamine and 41.8 g of water is metered in at 40 ° C. within 5 minutes. The stirring time at 40 ° C is 15 min. After removal of the solvent in vacuo, a storage-stable aqueous PU / crosslinker dispersion is obtained which has blocked isocyanate groups and has a solids content of 40.0%. The average particle size of the dispersion particles is 316 nm.

Example 9

160.5 g of the polyester PE 170 HN (Bayer AG, Leverkusen, DE, polyester based on adipic acid, neopentyl glycol and hexanediol with an average molecular weight of 1700 (OHZ = 66)) and 73.4 g of polyether LB 25 (Bayer AG, DE, monofunctional polyether based on ethylene oxide / propylene oxide with an average molecular weight of 2250 (OHZ = 25)) are introduced and heated to 70.degree. 48.1 g of Desmodur® W are then added over the course of 5 minutes at 20 ° C. with stirring, the reaction mixture is heated to 100 ° C. and stirred at this temperature until the theoretical NCO value (2.17%) is reached. After cooling to 50 ° C., the prepolymer is dissolved within 5 minutes by adding 120.9 g of acetone. After adding 175.5 g of the blocked polyisocyanate from Example 1, the reaction mixture is stirred for a further 5 min. The dispersion is carried out by adding 547.3 g of water (20 ° C.) within 10 minutes. Immediately after dispersion, a solution is formed within 5 minutes 0.9 g of hydrazine monohydrate, 6.4 g of isophoronediamine and 39.4 g of water were metered in at 40.degree. The stirring time at 40 ° C is 15 min. After removal of the solvent in vacuo, a storage-stable aqueous PU / crosslinking agent dispersion is obtained which has blocked isocyanate groups and has a solids content of 40.6%. The average particle size of the dispersion particles is 329 nm.

Example 10: Comparative Example (conventional binder / crosslinking system of the prior art)

126.0 g of Baybond® PU 401 (polyurethane dispersion, Bayer AG, Leverkusen, DE) and 74 g of a crosslinker dispersion which are prepared as follows are stirred at 20 ° C. for 30 minutes.

Polyurethane Dispersion:

147.4 g of a biuret group-containing polyisocyanate based on 1,6-diisocyanatohexane (HDI) with an NCO content of 23.0% is placed at 40 ° C. 121.0 g of polyether LB 25 (Bayer AG, Lev., DE, monofunctional polyether based on ethylene oxide / propylene oxide with an average molecular weight of 2250 (OHZ = 25)) are metered in over the course of 10 minutes with stirring. The reaction mixture is then heated to 90 ° C. and stirred at this temperature until the theoretical NCO value is reached. After cooling to 65 ° C., 62.8 g of butanone oxime are added dropwise with stirring in the course of 30 minutes in such a way that the temperature of the mixture does not exceed 80 ° C. The dispersion is carried out by adding 726.0 g of water (T = 20 ° C) at 60 ° C within 30 minutes. The stirring time at 40 ° C is 1 h.

A storage-stable aqueous dispersion of the blocked polyisocyanate with a solids content of 30.0% is obtained.

Table 1: Results of the binders according to the invention from Example 4-9 and a comparative binder of the prior art (Example 10) on the basis of measurements of the mechanical properties on the free film

n. b. = not determined

The results in Table 1 demonstrate that the dispersions according to the invention are significantly superior to the binder / crosslinker mixture of the prior art with comparable mechanical properties (tensile strength and extensibility) in terms of hydrolysis resistance, water resistance and adhesion, in particular wet adhesion.

Claims

claims

1. Containing aqueous one-component (IC) coating systems

(I) at least one polyurethane (A) which contains chemically bound hydrophilic groups and a content of groups containing Zerewitinoff-active hydrogen atoms of 0 to 0.53 mmol / g, based on the non-volatile

Proportion of the dispersion, and

(II) at least one polyisocyanate (B) in which the NCO groups are reversibly blocked and which contains no hydrophilic groups and

(in water,

the quantitative ratio of components (A) and (B) is such that the

Blocked isocyanate content is between 0.01 and 1.0 mol / 100 g of solid resin.

2. Aqueous (IC) coating systems according to claim 1, characterized in that the polyurethane (A) is a reaction product

AI) polyisocyanates,

A2) polymeric polyols and / or polyamines with average molecular weights of 400 to 8000,

A3) optionally mono- or polyalcohols or mono- or polyamines or amino alcohols with molecular weights up to 400,

and at least one connection selected from

A4) Compounds which have at least one ionic or potentially ionic group and / or

A5) nonionically hydrophilized compounds.

3. Aqueous (IC) coating systems according to claim 1 or 2, characterized in that the polyurethane (A) contains a combination of nonionic (A4) and ionic (A5) hydrophilizing agents as building blocks.

4. Aqueous (IC) coating systems according to one or more of claims 1 to 3, characterized in that polyisocyanates (B) by reacting (B1) at least one polyisocyanate with aliphatic, cycloaliphatic, araliphatic and / or aromatically bound isocyanate groups, which has no hydrophilic groups with

(B2) at least one blocking agent

getting produced.

5. Aqueous (IC) coating systems according to claim 4, characterized in that the blocking agent for the isocyanate groups is pyrazole derivatives of the general formula (IV),

in which

R ¹ corresponds to one or more (cyclo) aliphatic hydrocarbon radicals, each with 1 to 12 carbon atoms, which contains no chemically bound hydrophilic groups, and

n can be an integer from 0 to 3, preferably 1 or 2,

is.

6. Aqueous (IC) coating systems according to claim 4 or 5, characterized in that the blocking agent is 3,5-dimethylpyrazole or 3-methylpyrazole.

7. The method for producing aqueous (IC) coating systems according to claim 1, characterized in that component (B) is mixed with the polyurethane (A) before dispersion.

8. A method for producing coatings, characterized in that the aqueous (IC) coating system according to claim 1 is applied to a substrate, the water is at least partially removed and then thermally hardened.

9. A method for producing coatings according to claim 8, characterized in that the substrate is glass or carbon fiber.

10. substrates coated with coating compositions containing (IC) coating systems according to claim 1.

11. Use of the aqueous (IC) coating systems according to claim 1 in glass fiber sizes.