DE19746327C1 - Aqueous coating material, especially for car base coat paint - Google Patents

Abstract

An aqueous coating material contains an aqueous binder dispersion based on a polymer hybrid comprising a polyurethane component with siloxane bridges and/or silanol groups and a polymer component derived from mono-unsaturated and poly-unsaturated comonomers. Aqueous coating material containing an aqueous binder dispersion (ABD) and possibly organic solvents, crosslinkers, pigments, fillers, conventional paint additives and/or other binders(s). The ABD is based on a polyurethane (PU)/polymer hybrid with a number-average mol. wt. (Mn) of 15000 to 1.5 x 10<6> and a weight ratio of PU/polymer = (0.05:1)-(50:1), in which the polymer component contains 5-45 wt% poly-unsaturated comonomer units (based on the sum of mono- and polyunsaturated comonomers) and the PU component contains siloxane bridges (-Si-O-Si-) and/or silanol groups, such that the hybrid shows a hydroxyl (OH) number of 0-150 mg KOH/g (based on solid resin and without taking into account Si-linked OH), an acid number of 1.5-60 mg KOH/g (based on solid resin) and a silicon content (as above) of 0.5-300 mmols Si/100 g solid resin. An Independent claim is also included for a process for the production of this coating material, in which the ABD is made from an acid group-containing PU prepolymer with (on average) 0.1-2 radically copolymerizable olefinic groups per molecule and 0.7-9 Si-linked OR' groups per molecule R' = 1-8C alkyl or -COR'; R' = 1-10C alkyl (possibly dissolved in inert solvent and pre-neutralized), by dispersion in water and cppolymerization with mono- and polyunsaturated comonomers. The ABD may then be mixed with other paint components as above.

Description

The invention relates to aqueous coating compositions, the aqueous binder dispersions contain on the basis of hybrid polymers, which are produced by radical copolymerization of siloxane bridges and / or silanol groups and polyurethane resins containing olefinic double bonds together with mono- and polyunsaturated comonomers. It also relates to processes for the production of aqueous coating compositions and their use for multilayer painting, in particular as a water-based paint in manufacturing processes decorative multi-layer lacquers of the type water-based lacquer / clear lacquer. Unless otherwise stated, means the one used above and below Syllable or the term "unsaturated" "olefinically unsaturated".

The applicant has in the as yet unpublished international patent application PCT / EP 97/04821 aqueous coating agent which can be used as a water-based lacquer high run-off limit proposed, based on the aqueous binder dispersions of hybrid polymers, which are produced by radical Copolymerization of siloxane bridges and / or silanol groups as well as olefinic Double bonds containing polyurethane resins together with olefinic unsaturated comonomers. In addition, polyunsaturated comonomers can monounsaturated comonomers are used in small amounts. It has now surprisingly emerged that the adhesive properties of this aqueous coating agents can be improved especially in refinish coatings can, if the proportion of polyunsaturated comonomers within the Polymer portion of the hybrid polymer contained in the aqueous coating agent is increased.

The object of the invention is therefore to provide aqueous coating compositions which are particularly suitable for multi-layer coatings, in particular for  Creation of color and / or effect layers. They are said to be in only one can be applied in a single coat in high layer thicknesses to form a covering coat be and achieve good adhesion properties.

It has been shown that this problem can be solved by aqueous Coating agents containing binder dispersions based on Polyurethane / polymer-polymer hybrids with a number average molecular weight (Mn) from 15000 to 1500000, a weight ratio of polyurethane to Polymer fraction from 0.05: 1 to 50: 1, preferably up to 10: 1, with a fraction of in the polymer portion of the polyurethane / polymer-polymer hybrid polymerized polyunsaturated comonomers from 5 to 45, preferably from 5 to 25% by weight, based on the sum of polymerized into the polymer portion mono- and polyunsaturated comonomers, with a hydroxyl number from 0 to 150, preferably less than 100 mg KOH / g, based on solid resin, with those bound to silicon Hydroxyl groups are not included in the calculation of the OH number, and an acid number of 1.5 to 60 mg KOH / g, preferably 3 to 40 mg KOH / g, based on solid resin, and a content of 0.5 to 300 mmol, preferably 1 to 200 mmol, particularly preferably 5 to 75 mmol silicon per 100 g solid resin in the form of Polyurethane part integrated siloxane bridges (-Si-O-Si-) and / or in the form of the polyurethane portion bound silanol groups.

The hybrid polymers consist of polyurethane and polymer blocks and they have a branched structure, for example as a comb polymer, or they lie in the form of microgels. When building the polymer portion of the Polyurethane / polymer-polymer hybrids for polymerization olefinic double bonds of the mono- and polyunsaturated comonomers are allylic and / or vinyl double bonds and / or alpha, beta-unsaturated carbonyl groups, for example preferably (meth) acrylic Double bonds. The proportion of allylic double bonds is preferred less than 10%, while it is preferably at least 50%, preferably more than 70% is (meth) acryloyl groups. Are more than 50% of those at the Polymerization involved olefinic double bonds (meth) acryloyl groups, see above  the hybrid polymers are polyurethane / poly (meth) acrylate Polymer hybrids. According to the invention, the polymer content is 5 to 45, preferably 5 up to 25 wt .-% of polyunsaturated comonomers, based on the Sum of mono- and polyunsaturated polymerized into the polymer part Comonomers.

The used in the aqueous coating compositions according to the invention Binder dispersion based on polyurethane / polymer-polymer hybrids has an acid number based on solid resin of 1.5 to 60 mg KOH / g, preferably 3 up to 40 mg KOH / g. The acid groups are preferred to at least 80%, preferably exclusively part of the polyurethane component. The acid groups serve the stabilization of the polymer hybrid particles in the aqueous phase. The Polyurethane / polymer-polymer hybrids can be additional stabilizing Contain hydrophilic nonionic groups, for example those customary for this purpose Polyalkylene oxide groups.

The used in the aqueous coating compositions according to the invention Binder dispersion based on polyurethane / polymer-polymer hybrids has a hydroxyl number based on solid resin of 0 to 150, preferably less than 100 mg KOH / g. A possible hydroxyl number of the binder can be derived from the Polyurethane portion and / or derive from the polymer portion.

The aqueous binder dispersions based on polyurethane / polymer-polymer hybrids can be prepared, for example, by using a polyurethane prepolymer containing acid groups, the average 0.1 to 2 radical copolymerization accessible olefinically unsaturated groups per molecule and an average of 0.7 to 9 Has silicon-bonded R'O groups per molecule, wherein

R '= C1 to C8 alkyl or C (O) R''', and
R '''= C1 to C10 alkyl

mean, and are present in a solution inert to isocyanate can, optionally after prior neutralization of the acid groups by addition converted from water into an aqueous dispersion and then together with mono- and polyunsaturated comonomers undergo radical polymerization. The mono- and polyunsaturated comonomers can be used before and / or after Preparation of the aqueous dispersion can be added. For example, the or part of the mono- and polyunsaturated comonomers before the preparation of the aqueous dispersion the function of a solvent inert to isocyanate take over which does not have to be removed again.

The preparation of the polyurethane prepolymers with an average of 0.7 to 9 R'O groups per molecule preferably bound to lateral and / or terminal silicon and an average of 0.1 to 2 lateral and / or terminal olefinically unsaturated groups per molecule which are accessible to free-radical copolymerization can be carried out, for example, by producing a linear or branched, non-gelled, free of olefinic double bonds, containing acid groups and hydroxy-functional polyurethane prepolymers in an inert organic solvent (mixture) and / or in one or more isocyanate-inert olefinically unsaturated monomers or in the absence of solvents and olefinically unsaturated monomers, reaction of the hydroxyl groups of the polyurethane prepolymer thus obtained with one or more silanes of the general formula

((OCN-) _n R) _a Si (OR ') _b (R ") _c

with R = a bifunctional, trifunctional or tetrafunctional, preferably bifunctional organic radical with a molecular weight of 13 to 500, preferably (ar) alkylene with 1 to 12 C atoms, particularly preferably alkylene with 1 to 12 C atoms, R '= C1 to C8-alkyl or C (O) R "", preferably C1 to C4-alkyl, R "= R""= C1 to C10-alkyl, where R" and R "" can be the same or different , a = 1, 2 or 3, preferably 1, b = 1, 2 or 3, preferably 2 or 3, c = 0.1 or 2, n = 1 to 3, preferably 1 or 2, particularly preferably 1, with several Radicals R ', R "and R""are identical or different and in which the sum of a plus b plus c results in four,
and with one or more olefinically unsaturated monomers which have one or more isocyanate groups.

The polyurethane prepolymers are preferably produced with an average of 0.7 to 9 R'O groups per molecule, preferably bound to lateral and / or terminal silicon, and an average of 0.1 to 2 lateral and / or terminal olefinically unsaturated groups which are accessible to free-radical copolymerization per molecule, for example:

• 1. Preparation of a linear or branched, non-gelled, of olefinic Double bonds free, containing acid groups as well isocyanate-functional polyurethane prepolymers in one or more inert organic solvents and / or in one or more in a mixture existing olefinically unsaturated monomers which are inert to isocyanate or in the absence of solvents and olefinically unsaturated monomers,
• 2. Implementation of the Free Isocyanate Groups of the Polyurethane So Obtained Prepolymers
• 3. with one or more compounds of the general formula
  ((HX-) _n R) _a Si (OR ') _b (R ") _c (I)
  with X = O, S, NH or NR ' ^v , preferably NH or NR' ^v ,
  R = a bifunctional, trifunctional or tetrafunctional, preferably bifunctional organic radical with a molecular weight of 13 to 500, preferably (ar) alkylene with 1 to 12 C atoms, particularly preferably alkylene with 1 to 12 C atoms,
  R '= C1 to C8 alkyl or C (O) R''', preferably C1 to C4 alkyl,
  R "= R '''= C1 to C10 alkyl, where R" and R''' can be the same or different,
  R ' ^v = C1 to C8 alkyl,
  a = 1, 2 or 3, preferably 1,
  b = 1, 2 or 3, preferably 2 or 3,
  c = 0, 1 or 2,
  n = 1 to 3, preferably 1 or 2, particularly preferably 1,
  where several radicals R ', R "and R""are identical or different and in which the sum of a plus b plus c results in four
• 4. with one or more capable of addition to isocyanate groups, olefinically unsaturated monomers,
• 5. optionally with one or more NH ₂ - and / or NH groups carrying alkanolamines with an OH functionality of at least 1, and
• 6. optionally with one or more aliphatic C4-C36 alcohols and / or amines.

The production of the R'OSi functionalized and on average 0.1 to 2 olefinic Double bonds per molecule containing polyurethane prepolymers via NCO Prepolymers can be carried out in a so-called one-step process, d. H. Process steps 1) and 2) described above can be carried out simultaneously be carried out by the reactants required there simultaneously with one another be implemented or preferably in the sequential manufacturing process. In the Selection of the reactants, the reaction conditions and the order of the Addition of the individual reactants is important to ensure that undesirable Side reactions can be excluded.  

The production of the linear or branched, non-gelled, acid groups free of olefinic double bonds containing and isocyanate-functional polyurethane prepolymers for example, by reacting one or more compounds with at least two groups reactive towards isocyanate, in particular one or several polyols, preferably diols, with one or more organic Polyisocyanates, preferably diisocyanates and with one or more compounds with more than one, preferably two groups reactive toward isocyanate groups and at least one acid group.

For example, a polyurethane prepolymer containing NCO groups, which can be used as a starting product, can be prepared by reaction in an anhydrous environment of

• 1. at least one linear or branched compound, the at least two groups reactive towards isocyanate contribute with a medium Molecular weight of 60-10000, preferably 60-6000,
• 2. at least one organic polyisocyanate, in particular diisocyanate,
• 3. at least one compound with more than one isocyanate-reactive groups, and at least one acid group, with a number-average molecular weight (Mn) up to 10,000, preferably up to 2,000
  in an NCO / OH ratio of over 1 to 4: 1.

It is preferably the linear or branched one mentioned above Compound of component b1) by at least one polyol based on or several polyethers, polyesters and / or polycarbonates, with at least two OH Groups in the molecule and a number average molecular weight (Mn) of 600-10000, preferably more than 1000 and less than 6000, optionally with the use of one or several at least difunctional low molecular weight alcohols and / or  Amines and / or amino alcohols with a molecular weight below 600, preferably below 400.

All manufacturing processes for polyurethane prepolymers containing NCO groups can be carried out as a single or multi-stage process.

The polyurethane prepolymer containing isocyanate groups preferably has one Content of urethane - (- NHCOO-) and optionally urea - (- NHCONH-) groups between 10 and 300 milliequivalents per 100 g solid resin.

The polyurethane prepolymers used to produce the NCO groups as Component b1) compounds used can be, for example, a linear or branched polyol component, e.g. B. be diols. For example, it is polyols familiar to the person skilled in the art in the field of polyurethane chemistry be used. Assuming a linear diol component, the Achieve a branching of the polymer parts of polyols with a Functionality of 3 or more can be added. The quantity is to be chosen so that no gel formation during the synthesis of the polyurethane containing NCO groups Prepolymer occurs.

Examples of the polyol component b1) can be polyether polyols, in particular Polyether diols, for example polyethylene glycols, polypropylene glycols or Be polytetrahydrofuran diols.

Polyester polyols can be mentioned as further examples of polyol components b1) become. You can z. B. by esterification of organic Produce dicarboxylic acids or their anhydrides with organic polyols. The Dicarboxylic acids and the polyols can be aliphatic, cycloaliphatic or aromatic dicarboxylic acids and polyols. The polyesters preferably have a molecular weight of 300 to 6000, an OH number of 20 to 400 and one Acid number of less than 3, preferably less than 1. Linear polyesters are preferred, So polyester diols used.  

As component b1) z. B. also polycarbonate diols can be used.

It is also possible to use polyester polyols, preferably diols, which are derived from lactones derive, use as component b1).

In the case of the low molecular weight compounds which may also be used in b1) especially alcohols and amines. They are from the Polyurethane chemistry known per se in the sense of an isocyanate addition reaction having at least difunctional hydroxyl and / or amino groups Compounds with a molecular weight below 600, preferably below 400. It come both in the sense of the isocyanate addition reaction difunctional compounds as well as at least trifunctional or any mixtures of such compounds into consideration.

Any organic polyisocyanates, such as. B. Diisocyanates are used. Aliphatic, cycloaliphatic, aromatic or araliphatic diisocyanates can be used. examples for suitable diisocyanates are hexamethylene diisocyanate, isophorone diisocyanate, bis- (4- isocyanatocyclohexyl) methane, bis (4-isocyanatophenyl) methane, Tetramethylxylylene diisocyanate and 1,4-cyclohexylene diisocyanate.

Low-molecular compounds can preferably be used as component b3) be having more than one, preferably two or at least two Contain groups reacting isocyanate groups and at least one acid group. Suitable groups which react with isocyanate groups are in particular Hydroxyl groups and primary and secondary amino groups. As acid groups come z. B. carboxyl, phosphoric acid and sulfonic acid groups into consideration. The preferred acid groups to be introduced are carboxyl groups; you can for example by using hydroxyalkane carboxylic acids as a component b3) are introduced. Dihydroxyalkanoic acids are preferred, in particular alpha, alpha-dimethylolalkanoic acids such as alpha, alpha-dimethylolpropionic acid.  

Acidic polyesters such as those described, for example, in DE-A 39 03 804 are used.

The amounts of b1), b2) and b3) are chosen so that a during the implementation Reaction product with lateral and / or terminal NCO groups arises, d. H. it is worked with an excess of polyisocyanate. One can with an NCO too OH ratio of over 1 to 4: 1, the range from 1.1 to 2: 1 is preferred, particularly preferably from 1.1 to 1.7: 1. The reaction product can be branched be constructed, but in general it is preferably linear with terminal NCO groups.

The polyurethane prepolymer containing NCO groups obtained in process step 1) is processed in process step 2).

• 1. with one or more compounds of the general formula
  ((HX-) _n R) _a Si (OR ') _b (R ") _c (I)
  with X = O, S, NH or NR ' ^v , preferably NH or NR' ^v ,
  R = bifunctional to tetrafunctional, preferably bifunctional organic radical with a molecular weight of 13 to 500, preferably (ar) alkylene with 1 to 12 C atoms, particularly preferably alkylene with 1 to 12 C atoms,
  R '= C1 to C8 alkyl or C (O) R''', preferably C1 to C4 alkyl,
  R "= R '''= C1 to C10 alkyl,
  R ' ^v = C1 to C8 alkyl,
  a = 1, 2 or 3, preferably 1,
  b = 1, 2 or 3, preferably 2 or 3,
  c = 0, 1 or 2,
  n = 1 to 3, preferably 1 or 2, particularly preferably 1 and in which the sum of a plus b plus c is four,
• 2. with one or more capable of addition to isocyanate groups, olefinically unsaturated monomers,
• 3. optionally with one or more NH ₂ - and / or NH groups carrying alkanolamines with an OH functionality of at least 1, and
• 4. optionally with one or more aliphatic C4-C36 alcohols and / or amines

to an R'OSi-functionalized and olefinic containing acid groups Implemented double bonds containing polyurethane prepolymers.

The compounds of the general formula (I) are silane derivatives which have active hydrogen-containing groups of the (HX-) _n R- type, which are capable of addition to isocyanate groups, where X is as defined above. As the active hydrogen-containing functional groups HX-, amino groups are preferred. n has values from 1 to 3, preferably n assumes the value 1. The radical R is a bifunctional to tetrafunctional, preferably bifunctional, organic radical which can carry chemically inert groups or substituents with a molecular weight of 13 to 500. The radical R is preferably a bifunctional aralkylene radical or alkylene radical with 1 to 12 carbon atoms. An alkylene radical having 1 to 12 carbon atoms is particularly preferred as the radical R.

The silane derivative of the general formula (I) also contains 1 to 3, preferably 2 or 3 R'O groups bonded to silicon, where R 'preferably has the meaning of C1 to C8 alkyl.

As some preferred examples of compounds (I) Aminoethyltriethoxysilane, gamma-aminopropyltriethoxysilane, gamma  Aminopropyltrimethoxysilane, gamma-aminopropylethyldiethoxysilane, gamma Aminopropylphenyldiethoxysilane, gamma-aminopropyltrimethoxysilane, delta- Aminobutyltriethoxysilane, delta-aminobutylethyldiethoxysilane, N- (2-aminoethyl-3- aminopropyl) trimethoxysilane, N-2-aminoethyl-3-aminopropyl-tris (2-ethylhexoxy) silane, 6- (aminohexylaminoproyl) trimethoxysilane, N-aminoethyl-3-aminopropylmethyl called dimethoxysilane.

The olefinically unsaturated monomers used in process step a2) which are capable of addition to isocyanate groups are compounds having active hydrogen and preferably having only one copolymerizable olefinic double bond in the molecule. Active hydrogen is contained, for example, in hydroxyl groups, NH groups, NH ₂ groups or mercaptan groups. In the context of the present invention, preference is given to compounds having active hydrogen in the form of hydroxyl groups, preferably having only one hydroxyl group, and having a copolymerizable olefinic double bond in the molecule, in particular in the form of a (meth) acryloyl group. Examples of such compounds are allyl alcohol, but especially hydroxyalkyl (meth) acrylates, such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate or butanediol mono (meth) acrylate, glycerol mono (meth) acrylate, adducts of (meth) acrylic acid with monoepoxides such as, for . B. Versatic acid glycidyl ester, adducts of glycidyl (meth) acrylate with monocarboxylic acids such as. B. acetic acid or propionic acid.

The implementation of the NCO-functional polyurethane prepolymer to the R'OSi- Functionalized polyurethane prepolymers take place with complete consumption of the HX groups of the compounds (I) and preferably also that of isocyanate reactive groups of the olefinically unsaturated monomers.

The polyurethane / polymer hybrid polymer on which the binder dispersion used in the aqueous coating composition according to the invention is based may have hydroxyl groups. If this is desired, the polyurethane prepolymer containing NCO groups can be used in the preparation of the R'OSi and unsaturated functionalized polyurethane prepolymer in the course of optional process step a3) with at least one alkanolamine carrying NH ₂ and / or NH groups an OH functionality of at least 1 can be implemented. The reaction then takes place with complete consumption of the NH ₂ and / or NH groups of the alkanolamine.

The alkanolamines carrying NH ₂ and / or NH groups and having an OH functionality of at least 1 are compounds which can serve as suppliers for hydroxyl groups in the binder dispersion and alone or together with any hydroxyl groups from the poly (meth) Contribute acrylate to the hydroxyl number of the binder. Compared to their OH groups, the NH or NH ₂ groups of the alkanolamines have a significantly higher reactivity than the isocanate groups of the NCO-functional PU prepolymer, ie the NH groups react preferentially with the isocyanate groups to form urea.

Examples of suitable alkanolamines with an OH functionality of at least 1 are monoalkanolamines and dialkanolamines, e.g. B. Diethanolamine, N- Methylethanolamine, diisopropanolamine, N-ethylisopropanolamine, Monoisopropanolamine, ethanolamine, 2,2-aminoethoxyethanol, Monoethylethanolamine, butylethanolamine, cyclohexylethanolamine, 3-aminopropanol, 2-aminobutanol-1.

It may be expedient if, instead of or together with the alkanolamines carrying the NH ₂ and / or NH groups, one or more aliphatic C4-C36 alcohols and / or amines are also used in the optional process step a4), the reaction of which then in usually takes place with complete consumption of their OH, NH and / or NH ₂ groups. Fatty amines and / or fatty alcohols with more than 12 carbon atoms are preferred. Examples are lauryl alcohol, stearyl alcohol and the corresponding amines.

The isocyanate groups of the NCO-functional polyurethane prepolymer are added the HX groups of (I), the isocyanate-reactive groups of the olefinic  unsaturated monomers, the NH groups of the optionally used Alkanolamine and the isocyanate-reactive groups of the optionally C4-C36 alcohol and / or amine used preferably in the stoichiometric Relationship brought to reaction. It can alkanolamine, C4-C36 alcohol and / or amine, the isocyanate-reactive olefinically unsaturated monomer and the compound (I) in a mixture or in succession in a suitable order the NCO-functional polyurethane prepolymer.

In the polyurethane prepolymer thus obtained with an average of 0.7 to 9 silicon bound R'O groups per molecule and an average of 0.1 to 2 one radical copolymerization accessible olefinically unsaturated groups per Any remaining free isocyanate groups that may remain in the molecule may be present compared to the transfer of the prepolymer into the water phase with the usual Isocyanate capable of addition, active hydrogen-containing compounds be implemented. Examples of suitable active hydrogen-containing Compounds are monoalcohols, diols, glycol ethers, monoamines, diamines.

The implementation of the polyurethane prepolymer to build the NCO-functional used components as well as the further implementation to the R'OSi- Functionalized polyurethane prepolymers take place in an anhydrous environment for example at temperatures from 20 to 140 ° C, preferably between 50 and 100 ° C. It can be worked solvent-free or it is in the specialist common organic solvents suitable for polyurethane synthesis worked. Water-miscible solvents or water-immiscible solvents are used. In general, it is advantageous to use such solvents at any stage of the preparation of the aqueous Binder dispersion (for example, after its completion) are removed can, for example by distilling off, if necessary, under reduced pressure Pressure.

Examples of suitable solvents are ketones, e.g. B. acetone, methyl ethyl ketone, Methyl isobutyl ketone; N-alkyl pyrrolidones, such as. B. N-methylpyrrolidone; Ether like  e.g. B. diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, or cyclic urea derivatives such as 1,3-dimethyl-3,4,5,6-tetrahydro-2 (1H) pyrimidinone.

The resulting polyurethane prepolymer with an average of 0.7 to 9 silicon bound R'O groups per molecule and an average of 0.1 to 2 one radical copolymerization accessible olefinically unsaturated groups per Molecule is converted into an aqueous dispersion by adding water, preferred after neutralizing its acid groups. The acid groups can with a neutralizing agent completely or partially in the corresponding Salt groups are transferred. This can occur in all stages of the above described synthesis happen, it should be noted that the selection of the for Salt formation used compounds is taken so that this during the Behavior chemically inert.

Bases serve for neutralization, e.g. B. amines, preferably tertiary amines. examples for suitable bases are ammonia or organic amines such as 2-amino-2- methylpropanol-1, trialkylamines, such as trimethylamine, triethylamine, Triisopropylamine; N-alkylmorpholines, such as N-methylmorpholine; N- Dialkylalkanolamines such as N-dimethylethanolamine and N-dimethylisopropanolamine and their mixtures.

The conversion into the aqueous dispersion can be carried out in such a way that the polyurethane Prepolymer is mixed with water. To do this, the total amount of water once or preferably only a part of the total amount of water with the Polyurethane prepolymer can be mixed. The water can be added to the resin become. It is also possible to add the resin to the water.

The R'OSi groups of the polyurethane prepolymer are sensitive to hydrolysis. about different products can be obtained during the course of the water addition. For example, it can be controlled whether the hybrid binder is silicon in the form of in the polyurethane portion integrated siloxane bridges (-Si-O-Si-) or in the form of contains the polyurethane portion bound silanol groups or as the ratio of  Siloxane bridges to silanol groups.

If the hybrid polymer silicon in the form of silanol groups, for example in contain essentially only in the form of silanol groups, it is essential that within a short time such an amount of water is added that is sufficient is a further reaction of the silanol groups formed by hydrolysis prevent. The water is added in more than ten times stoichiometric Excess of the amount of water necessary for the hydrolysis of the R'OSi groups. The at least 50-fold stoichiometric excess is preferably added. The water is particularly preferably added in such an amount that at least half of those required to prepare the aqueous dispersion Amount of water is added all at once. By adding the sufficient Amount of water becomes a condensation of water which runs off Hydrolysis of silanol groups to siloxane bridges largely avoided, d. H. an aqueous dispersion of a polyurethane resin is obtained which is practically free is of siloxane bridges and contains silanol groups.

However, the polyurethane prepolymer is preferably chain extended Subjected to siloxane bridging by using a small amount to transfer to the aqueous phase insufficient amount of water, for example preferably in adding at least a stoichiometric amount for the hydrolysis of the R'OSi groups and the reaction product during or after the chain extension, if necessary after complete or partial neutralization converted into an aqueous dispersion. The Chain extension of the R'OSi-functionalized polyurethane prepolymer takes place after adding a preferably up to a maximum of ten times stoichiometric Excess, particularly preferably up to a maximum of five times stoichiometric Excess, calculated on the necessary for the hydrolysis of the R'OSi groups Amount of water. The hydrolysis of the R'OSi groups takes place quickly. By Hydrolysis formed silanol groups condense with elimination of water Siloxane bridges and thus lead to a chain-extended polyurethane resin that is practically free of silanol groups, for example over 80%, in particular over 90% of the silicon bound as siloxane bridges. Depending on the used  R'OSi-functionalized polyurethane prepolymers become linear, branched or networked products.

The conversion of the optionally neutralized reaction product into an aqueous Dispersion with the addition of a sufficient amount of water can occur during or after the chain extension and the formation of the siloxane bridges takes place in the dispersed or non-dispersed resin phase, i.e. H. the chain extension runs in the resin phase; if the resin has already been added sufficiently Water is dispersed, the chain extension runs in the Dispersion particles themselves.

The hydrolysis reaction and, if appropriate, the one that takes place Chain extension can, if desired, be carried out at elevated temperature become. For example, temperatures up to 95 ° C are suitable.

The preparation of the aqueous dispersion of the siloxane bridges and / or silanol groups having polyurethane resin can be done by known methods.

For example, it is possible to submit the neutralized resins and under good conditions Disperse with water. Likewise, if necessary Water phase containing neutralizing agent and the resin with stirring be incorporated. Continuous operation is also possible. H. it are in known units, for. B. a rotor-stator mixer, at the same time resin, Water and neutralizing agent mixed together homogeneously. The transfer to the water phase can be supported by increased temperature.

The polyurethane resin, which is solvent-free or in organic solution, becomes transferred into the aqueous phase by adding sufficient amounts of water. The Addition of the amount of water sufficient for transfer into the aqueous phase after completing the chain extension. It is also possible that Main amount of water during chain extension or after hydrolysis of the Add R'OSi groups. A fine-particle polyurethane dispersion results an average particle size of greater than 10 and less than 2000 nm, preferably above  50 and below 500 nm. The distribution can be monomodal or bimodal, preferred be monomodal.

After creating the aqueous dispersion of the siloxane bridges and / or Silanol groups, preferably essentially only having siloxane bridges The last stage of synthesis in the manufacture of the polyurethane resin occurs Binder dispersion. This is the structure of the polymer content of the polyurethane / polymer-polymer hybrid binder by radical Polymerization according to known methods. The copolymerization or Graft polymerization of the lateral and / or terminal olefinic double formations of the polyurethane resin takes place together with mono- and polyunsaturated Comonomers. The polymerization can be carried out so that the polyunsaturated Comonomers with complete consumption of their olefinic double bonds be polymerized or that part of the polyunsaturated comonomers under polymerized incomplete consumption of their olefinic double bonds. For example, part of the polyunsaturated comonomers can be with only part their respective unsaturated groups are polymerized, so that the Polymer portion of the resulting polyurethane / polymer-polymer hybrid can have olefinic double bonds.

The olefinic double bonds obtained for the polymerization are allylic and / or vinyl double formations and / or alpha, beta unsaturated carbonyl groups, for example preferably (meth) acrylic Double bonds. The proportion of allylic double bonds is preferred less than 10%, while it is preferably at least 50%, preferably more than 70% is (meth) acryloyl groups.

It is essential to the invention that the polymer content is 5 to 45, preferably 5 to 25% by weight, based on the sum of polymerized into the polymer portion mono- and polyunsaturated comonomers, from polyunsaturated comonomers is constructed. The comonomers can be used as a subset or completely - like mentioned above in their function as a solvent during the synthesis of the  Polyurethane resin - already in the aqueous dispersion, or they will be preferably added at least as a partial amount after the aqueous dispersion has been prepared and polymerized. Comonomers and radical initiators can work together, for example as a mixture or dissolved or separated into one another, for example also be added at different times. It may be appropriate to use the comonomer and initiator addition so that during the radical Polymerization did not result in changes in the solids content.

The radical polymerization is carried out at temperatures between 20 and 95 ° C, preferably between 60 and 90 ° C, carried out.

Examples of radical initiators which can be used in conventional amounts are peroxide compounds such as dialkyl peroxides, diacyl peroxides, organic Hydroperoxides, peresters, ketone peroxides; Azo compounds, such as Azobisisobutyronitrile. Water-soluble radical initiators such as for example hydrogen peroxide, ammonium peroxodisulfate, ammonium persulfate, Ammonium salts of 4,4'-azobis (4'-cyanopentanoic acid), 2,2'-azobis (2-methyl-N-1,1- bis (hydroxymethyl) ethyl) propionamide, 2,2'-azobis (2-methyl-N-2- hydroxyethyl) propionamide.

It is also possible to carry out the polymerization as a redox polymerization using appropriate redox initiator systems such as Sodium sulfite, sodium dithionite, ascorbic acid and peroxide compounds.

According to the invention 5 to 45, preferably 5 to 25 wt .-% polyunsaturated Comonomers, based on the sum of the polymer content polymerized mono- and polyunsaturated comonomers, in the Polymerized polymer portion of the polymer hybrid. With the polyunsaturated Comonomers are usually exclusively low molecular weight, by a molecular formula defined compounds with a molecular weight of in general below 500. Examples are divinylbenzene, hexanediol di (meth) acrylate, ethylene and Propylene glycol di (meth) acrylate, 1,3- and 1,4-butanediol di (meth) acrylate,  Vinyl (meth) acrylate, allyl (meth) acrylate, diallyl phthalate, glycerol tri- and - di (meth) acrylate, trimethylolpropane tri and di (meth) acrylate, pentaerythritol tri and tetra (meth) acrylate, di- and tripropylene glycol di (meth) acrylate.

The polyunsaturated comonomers, which are low molecular weight defined compounds with a molecular weight of generally less than 500, can be replaced to a small extent by polyunsaturated prepolymers. The proportion of polyunsaturated prepolymers can be up to 25% by weight, based on the sum of polyunsaturated defined by sum formula Comonomers and polyunsaturated prepolymers. With the radical polymerizable, polyunsaturated prepolymers are one Molecular formula of indefinable poly- or oligomers that are radical polymerizable, olefinic double bonds, especially (meth) acryloyl groups have in the molecule. In addition to the free radicals, the prepolymers contain polymerizable olefinic double bonds preferably no further functional groups. Examples of prepolymers or oligomers are (meth) acrylic functional (meth) acrylic copolymers, epoxy resin (meth) acrylates, Polyester (meth) acrylates, polyether (meth) acrylates, polyurethane (meth) acrylates, unsaturated polyesters with number average molecular weights (Mn) preferably in Range from 200 to 10,000, particularly preferably from 500 to 3000 and with on average 2 to 20, preferably 2 to 10 free-radically polymerizable, olefinic double bonds per molecule.

In addition to the polyunsaturated comonomers, monounsaturated comonomers become polymerized into the polymer portion of the hybrid polymer. It can be act exclusively as non-functional comonomers or they are both functional and non-functional comonomers.

Examples of radically polymerizable, monounsaturated comonomers, which besides the olefinic double bond carry no further functional group monovinyl aromatic compounds preferably having 8 to 10 carbon atoms each Molecule such as styrene, vinyl toluene; Vinyl ethers and vinyl esters, such as vinyl acetate,  Vinyl versatate; Maleic, fumaric, tetrahydrophthalic acid dialkyl esters, but especially (Cyclo) alkyl (meth) acrylates, such as methyl (meth) acrylate, ethyl (meth) acrylate, Propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, Cyclohexyl (meth) acrylate, ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, Lauryl (meth) acrylate, isobornyl (meth) acrylate.

Examples of in addition to the non-functional olefinically monounsaturated Comonomers usable olefinically monounsaturated comonomers with functional Groups are those with CH-acidic, epoxy, hydroxyl or carboxyl groups, it should be noted that the carboxy-functional comonomers form no more than 20% of the acid number of the polyurethane / polymer-polymer hybrid binder should contribute.

Examples of olefinically monounsaturated comonomers with hydroxyl groups that alone or together with any hydroxyl groups from the polyurethane component Allyl alcohol, in particular, can contribute to the hydroxyl number of the binder but hydroxyalkyl (meth) acrylates, such as hydroxyethyl (meth) acrylate, Hydroxypropyl (meth) acrylate or butanediol mono (meth) acrylate, Glycerol mono (meth) acrylate, adducts of (meth) acrylic acid with monoepoxides such. B. Versatic acid glycidyl ester, adducts of glycidyl (meth) acrylate with monocarboxylic acids such as B. acetic acid or propionic acid.

Examples of comonomers containing carboxyl groups are unsaturated carboxylic acids, such as B. (meth) acrylic, itacon, croton, isocroton, aconite, maleic and Fumaric acid, half ester of maleic and fumaric acid.

In the preparation of the aqueous binder dispersion, the proportions of individual starting materials preferably chosen and the reaction carried out so that the aqueous polyurethane dispersion-based polyurethane / polymer Hybrid polymers have a number average molecular weight (Mn) of 15,000 to 1,500,000 Weight ratio of polyurethane to polymer content from 0.05: 1 to 10: 1, a portion of in the polymer portion of the polyurethane / polymer  Polymer hybrids polymerized polyunsaturated comonomers from 5 to 45, preferably from 5 to 25% by weight, based on the sum of the polymer content polymerized mono- and polyunsaturated comonomers, a hydroxyl number from 0 to 150, preferably below 100 mg KOH / g, based on solid resin, with Silicon-bound hydroxyl groups are not included in the calculation of the OH number be counted, and an acid number of 1.5 to 60 mg KOH / g, preferably 3 to 40 mg KOH / g, based on solid resin and a content of 0.5 to 300 mmol, is preferred 1 to 200 mmol, particularly preferably 5 to 75 mmol silicon per 100 g solid resin in Form of siloxane bridges (-Si-O-Si-) and / or incorporated in the polyurethane component in the form of silanol groups bonded to the polyurethane portion.

The solids content of the aqueous coating compositions according to the invention binder dispersions used is, for example, between 25 and 65% by weight. %, preferably above 35 and below 60% by weight.

Any solvents contained in the aqueous binder dispersions can if desired, be removed by distillation. This can be reduced Pressure happen, for example before or after the radical polymerization.

The aqueous dispersions according to the invention can be obtained from the aqueous binder dispersions Coating agents are manufactured. These are preferably Water-based paints. The aqueous coating compositions according to the invention can be self-drying (physically drying), self-cross-linking or cross-linking. The basis of the aqueous binder dispersions Polyurethane / polymer-polymer hybrids have hydroxyl numbers between 0 and 150, preferably between 0 and 100 mg KOH / g. The hydroxyl number lies here preferably in the upper range if externally crosslinking aqueous Coating agents are to be produced.

For the production of aqueous coating compositions, preferably waterborne basecoats the aqueous binder dispersion, for example pigments and / or fillers, other binders, additives and possibly small amounts of solvents  added.

The aqueous coating compositions according to the invention can in addition to the aqueous Binder dispersion one or more additional binders different therefrom contain. Examples of such additional binders are familiar to the person skilled in the art usual film-forming water-soluble or water-dilutable resins, such as water-thinnable polyester resins, water-thinnable polyacrylate resins, water-dilutable polyurethane resins and / or such water-dilutable Binder in which (meth) acrylic copolymer and polyurethane resin or (Meth) acrylic copolymer and polyester resin covalently or in the form of interpenetrating Resin molecules are connected. It can be reactive or non-functional Act resins. The amount of the resins added can be 0 to 75% by weight, preferably 0 to 50 wt .-% of the total resin solids. Especially 0 to 30% by weight are preferred. In this context, resin means solid the sum of all binders without a crosslinker component.

Various can be used to prepare the aqueous coating compositions according to the invention Crosslinkers, such as formaldehyde condensation resins, such as phenolic Formaldehyde condensation resins and amine-formaldehyde condensation resins, and free or blocked polyisocyanates can be used. The crosslinkers can be used individually or used in a mixture. The mixing ratio crosslinker too The binder is preferably 10:90 to 40:60, particularly preferably 20:80 to 30:70, each based on the solid weight.

Furthermore, the aqueous coating compositions according to the invention can be known to the person skilled in the art contain known polymer microparticles. It can be networked or non-networked Microparticles are used.

The aqueous coating compositions according to the invention can also be used in coating technology Contain additives, for example rheology-influencing agents, such as highly disperse Silicic acid, inorganic layered silicates or polymeric urea compounds. As Thickeners also act, for example, as water-soluble cellulose ethers  Hydroxyethyl cellulose, methyl cellulose or carboxymethyl cellulose, as well synthetic polymers with ionic and / or associative groups such as Polyvinyl alcohol, poly (meth) acrylamide, poly (meth) acrylic acid, polyvinyl pyrrolidone, Styrene-maleic anhydride or ethylene-maleic anhydride copolymers and their Derivatives or hydrophobically modified ethoxylated polyurethanes or Polyacrylates. In addition, anti-settling agents, leveling agents, Light stabilizers, catalysts, anti-foaming agents, such as silicone-containing Links; Wetting agents and adhesion-promoting substances are used. Under Wetting agents are also understood to be known paste resins, those for the better Dispersion and grinding of the pigments can be used.

The solvent content of the aqueous coating compositions according to the invention is preferably below 20% by weight, particularly preferably below 15% by weight, in particular preferably less than 10% by weight. These are common paint solvents, these can come from the manufacture of the binders or are sold separately admitted. Examples of such solvents are monohydric or polyhydric alcohols, e.g. B. Propanol, butanol, hexanol; Glycol ether or ester, e.g. B. Diethylene glycol dialkyl ether, dipropylene glycol dialkyl ether, each with C1-6-alkyl, Ethoxypropanol, butyl glycol; Glycols e.g. B. ethylene glycol; Propylene glycol, and whose oligomers, N-alkylpyrrolidones, such as. B. N-methylpyrrolidone and ketones such as methyl ethyl ketone, acetone, cyclohexanone; aromatic or aliphatic Hydrocarbons, e.g. B. toluene, xylene or linear or branched aliphatic C6- C12 hydrocarbons.

The aqueous coating compositions according to the invention can have one or more inorganic and / or organic color and / or effect pigments and optionally additionally contain at least one filler.

Examples of effect pigments are metal pigments, e.g. B. made of aluminum, Copper or other metals; Interference pigments such as B. metal oxide coated Metal pigments, e.g. B. titanium dioxide coated aluminum, coated mica like e.g. B. titanium dioxide coated mica and graphite effect pigments. examples for  coloring pigments and fillers are titanium dioxide, micronized titanium dioxide, Iron oxide pigments, carbon black, silicon dioxide, barium sulfate, micronized mica, Talc, kaolin, chalk, azo pigments, phthalocyanine pigments, quinacridone pigments, Pyrrolopyrrole pigments, perylene pigments.

The effect pigments are generally in the form of a commercially available aqueous or submitted non-aqueous paste, optionally with preference water-dilutable, organic solvents and additives and then with mixed the aqueous binder under scissors. Powdery effect pigments can first with preferably water-dilutable organic solvents and Additives to be processed into a paste.

Color pigments and / or fillers can, for example, in part of the aqueous Binder are rubbed. The rubbing can preferably also be carried out in one special water-thinnable paste resin happen. An example of an im aqueous resin according to the invention preferably paste resin which can be used Polyurethane base can be found in DE-A-40 00 889. Grinding can be carried out in conventional Units known to the person skilled in the art take place. After that, with the rest Proportion of the aqueous binder or the aqueous paste resin for the finished product Color pigment rubbing completed.

If paste resins are present in the aqueous coating composition according to the invention, then these add up to binder plus when calculating the resin solids any crosslinker present.

The aqueous coating compositions according to the invention contain bases as Neutralizing agents, for example the same as above Neutralizing agent for the hybrid binder mentioned.

The aqueous coating compositions according to the invention are preferred as Waterborne basecoats formulated as used for and with multi-layer coatings transparent clear coats can be overcoated. Such a water-based paint has  for example a solids content of 10-50 wt .-%, for For example, water-based effect paints are preferably 15-30% by weight for monochrome water-based paints are preferably higher, for example 20-45 % By weight. The ratio of pigment to binder plus any crosslinking agent plus possibly paste resin in the water-based lacquer is between, for example 0.03: 1 to 3: 1; for effect waterborne basecoats, for example, it is preferred 0.06: 1 to 0.6: 1, it is preferably higher for plain-colored water-based paints, for example at 0.06: 1 to 2.5: 1, each based on the solid weight.

The waterborne basecoats according to the invention can be applied by customary methods become. They are preferred by spraying in a dry layer thickness of 8 to 50 µm applied, the dry layer thickness is for effect waterborne basecoats for example preferably 10 to 25 microns, for plain-colored water-based paints it is preferably higher, for example at 10 to 40 microns. The application can also be used for high layer thicknesses, for example 25 to 50 microns, carried out in one spray pass be, since the aqueous coating compositions of the invention have a high drainage limit exhibit. Several coats and an associated intermediate drying or Intermediate ventilation can be avoided. The application is preferably in Wet-on-wet process, i. H. after a flash-off phase, e.g. B. at 20 to 80 ° C. the waterborne basecoats with a common clearcoat in one Dry layer thickness of preferably 30 to 60 microns overcoated and together with this dried or crosslinked at temperatures of, for example, 20 to 150 ° C. The drying conditions of the top coat (waterborne basecoat according to the invention and clear coat) depend on the clear coat system used. For Repair purposes, for example, temperatures of 20 to 80 ° C are preferred. For The purpose of series painting is temperatures above 100 ° C, for example above 110 ° C preferred.

Basically all known clearcoats are transparent or transparent pigmented coating agent suitable. Both solvent-containing 1- or 2-component clear coats, water-thinnable clear coats, powder clear coats, aqueous powder clearcoat slurries or radiation-curable clearcoats are used  become.

Multicoat paint systems created in this way can be applied to a wide variety of substrates be applied. Generally it is metallic or plastic Substrates. These are often pre-coated, i.e. H. Plastic substrates can e.g. B. be provided with a plastic primer, metallic substrates have in generally an electrophoretically applied primer and optionally additionally one or more other layers of paint, such as. B. a filler layer. This Layers are generally cured.

Multicoat paint systems obtained with the waterborne basecoats of the invention correspond to the current requirements in automotive painting. The Waterborne basecoats according to the invention are thus suitable for the Vehicle painting and refinishing, but they can also be used in others Areas, e.g. B. the plastic painting, especially the vehicle parts painting, be used.

With the coating agents according to the invention, one can use create a multi-layered substrate, whereby the multilayer coating has been obtained by applying at least one Primer layer, preferably based on a water-dilutable coating agent, Applying a color and / or effect basecoat with a aqueous coating compositions according to the invention, optionally drying the Base coat and application of a transparent coating agent as a top layer and subsequent heating of the coated substrate. It can lead to this Multi-coat painting may add additional layers if necessary.

The aqueous coating compositions according to the invention are in particular as water-based paints to create the color and / or effect coating layer within one Suitable for multi-layer painting. The aqueous coating compositions according to the invention can also be applied in a single coat in a high layer thickness, which at the application of layers of paint with poorly covering hues  has special meaning. The aqueous coating compositions according to the invention have in addition to a high drainage limit, good adhesion properties especially in Repair build-up on overburned initial painting.

Production example 1:

145.4 g of a polyester made from adipic acid, neopentyl glycol and isophthalic acid (OH- Number: 109 mg KOH / g) and 8.0 g dimethylolpropionic acid are dissolved in 69.6 g N- Dissolved methylpyrrolidone and heated to 40 ° C. Then 55.8 g Isophorone diisocyanate added so that a reaction temperature of 80 ° C does not is exceeded. It is held until an NCO content of 2% (referred on solid resin and determined according to DIN 53185). After that in succession 7.0 g of 3-aminopropyltriethoxysilane, 12.2 g of dodecanol and 2.0 g Hydroxyethyl methacrylate added. The reaction mixture is at 80 ° C held until free NCO groups can no longer be detected (titration). Then 128.0 g of methyl methacrylate are added. 5.4 g of triethylamine and 5.4 g of deionized water added and worked in well. After the addition of 864.0 g of deionized water gives a finely divided aqueous dispersion. Now be 250.0 g of butyl acrylate, 125.0 g of tert-butyl acrylate and a solution of 62.0 g deionized water and 2.0 g ammonium peroxodisulfate at 80 ° C for 2 h continuously added. The mixture is then kept at 80 ° C. for 3 hours with deionized Water adjusted to a solid (60 '150 ° C) of 40.0 wt .-%.

Production example 2:

339.0 g of a polyester made from adipic acid, neopentyl glycol and Cyclohexanedicarboxylic acid (OH number 104 mg KOH / g) and 13.7 g Dimethylolpropionic acid are dissolved in 160.0 g of N-methylpyrrolidone and at 40 ° C. warmed up. Then 125.0 g of isophorone diisocyanate are added so that a Reaction temperature of 80 ° C is not exceeded. It is held until an NCO content of 2% (based on solid resin and determined according to DIN 53185) is reached. Then 43.8 g of 3-aminopropyltriethoxysilane, 4.5 g  Diethanolamine and 20.2 g of hydroxyethyl methacrylate added. The The reaction mixture is kept at 80 ° C. until no free NCO groups are more detectable (titration). Then 128.0 g of methyl methacrylate admitted. 9.2 g of triethylamine and 9.2 g of deionized water are added and well incorporated. After adding 1300.0 g of deionized water a finely divided aqueous dispersion. Now 240.0 g of butyl acrylate, 175.0 g tert-butyl acrylate and a solution of 100.0 g of deionized water and 4.0 g Ammonium peroxodisulfate at 80 ° C continuously added over 2 h. Subsequently is held for 3 h at 80 ° C and with deionized water on a solid (60 ' 150 ° C) of 40.0% by weight.

Production Example 3:

145.4 g of a polyester made from adipic acid, neopentyl glycol and isophthalic acid (OH- Number: 109 mg KOH / g) and 8.0 g dimethylolpropionic acid are dissolved in 69.6 g N- Dissolved methylpyrrolidone and heated to 40 ° C. Then 55.8 g Isophorone diisocyanate added so that a reaction temperature of 80 ° C does not is exceeded. It is held until an NCO content of 2% (referred on solid resin and determined according to DIN 53185). After that in succession 7.0 g of 3-aminopropyltriethoxysilane, 12.2 g of dodecanol and 2.0 g Hydroxyethyl methacrylate added. The reaction mixture is at 80 ° C held until free NCO groups can no longer be detected (titration). Then 128.0 g of methyl methacrylate are added. 5.4 g of triethylamine and 5.4 g of deionized water added and worked in well. After the addition of 864.0 g of deionized water gives a finely divided aqueous dispersion. Now be 50 g of 1,4-butanedio diacrylate, 200.0 g of butyl acrylate, 125.0 g of tert-butyl acrylate and one Solution of 62.0 g deionized water and 2.0 g ammonium peroxodisulfate at 80 ° C continuously added over 2 h. The mixture is then kept at 80 ° C. for 3 hours deionized water adjusted to a solid (60 '150 ° C) of 40.0 wt .-%.  

Production example 4:

339.0 g of a polyester made from adipic acid, neopentyl glycol and Cyclohexanedicarboxylic acid (OH number 104 mg KOH / g) and 13.7 g Dimethylolpropionic acid are dissolved in 160.0 g of N-methylpyrrolidone and at 40 ° C. warmed up. Then 125.0 g of isophorone diisocyanate are added so that a Reaction temperature of 80 ° C is not exceeded. It is held until an NCO content of 2% (based on solid resin and determined according to DIN 53185) is reached. Then 43.8 g of 3-aminopropyltriethoxysilane, 4.5 g Diethanolamine and 20.2 g of hydroxyethyl methacrylate added. The The reaction mixture is kept at 80 ° C. until no free NCO groups are more detectable (titration). Then 128.0 g of methyl methacrylate admitted. 9.2 g of triethylamine and 9.2 g of deionized water are added and well incorporated. After adding 1300.0 g of deionized water a finely divided aqueous dispersion. Now 82.0 g of 1,4-butanediol diacrylate, 158.0 g of butyl acrylate, 175.0 g of tert-butyl acrylate and a solution of 100.0 g deionized water and 4.0 g ammonium peroxodisulfate at 80 ° C for 2 h continuously added. The mixture is then held at 80 ° C for 3 h and with deionized water adjusted to a solid (60 '150 ° C) of 40.0 wt .-%.

Paint example 1 (comparison) 1.1 Production of a plain-colored, red water-based paint

300 g of a conventional paste resin (according to the example from DE-A-40 00 889) are with 350 g of a commercially available vat pigment (Color Index Red 168) mixed. With Dimethylethanolamine is brought to pH 8.5 and by adding deionized water adjusted to a solids content of 50% by weight. After that, in a pearl mill dispersed transparently.

1.2

1.4 g of a commercially available thickener based on polyacrylic acid (solid: 10% by weight  %, pH 7.5) with 129 g of the dispersion from preparation examples 1 and 40 g of the paste resin from Example 1.1 mixed. 17 g of hexamethoxymethylmelamine are added with stirring. Then 10 g of Red paste from Example 1.1 added and stirred in homogeneously. With deionized Water is adjusted to the application viscosity.

1.3 Apply the waterborne basecoat and a clearcoat

The waterborne basecoat obtained is applied to a conventional, phosphated and cathodic dip painting and body panel pre-coated with filler Spray applied in a dry layer thickness of 30 microns. After the application is flashed off at room temperature for 10 minutes and then at 10 minutes Pre-dried at 80 ° C. Then a commercially available, melamine resin curing Car series clear varnish based on acrylic resin in a dry layer thickness of 35 µm overpainted and a) 30 minutes or b) 120 minutes at 135 ° C (object temperature) dried.

One obtains the usual requirements in automotive OEM painting adequate multi-layer coating.

Furthermore, the waterborne basecoat obtained is applied to a customary, phosphated and thanks to cathodic dip painting and body panel pre-coated with filler applied by spraying in a wedge (dry layer thickness 0 to 50 µm). This happens by means of a painting machine without intermediate airing. The expiration limit is 40 µm.

Paint example 2 (comparative example)

Lacquer example 1 is repeated with the difference that instead of the dispersion Production Example 1 The dispersion from Production Example 2 is used. A No progress was observed, i. H. the drainage limit is over 50 µm.  

Paint example 3 (comparative example) Production of a silver-metallic two-layer paint

20 g of a commercially available aluminum paste with 65 % By weight aluminum, 20 g butylglycol, 6 g N-methylpyrrolidone and 1 g one Commercially available wetting agents are mixed together for the bronze digestion. Then 1.4 g of a commercially available thickener based on polyacrylic acid (Solids: 10 wt .-%, pH 7.5) added. Then 129 g of Dispersion from preparation example 1 and 40 g of the paste resin from coating example 1.1 stirred into the bronze dome. Then 17 g Hexamethoxymethylmelamine added. With deionized water is on Application viscosity set.

The waterborne basecoat obtained is applied to a conventional, phosphated and cathodic dip painting and body panel pre-coated with filler Syringes applied. This takes place in a dry layer thickness of 15 µm. After the application is flashed off at room temperature for 10 minutes and then 10 Pre-dried for minutes at 80 ° C. Then a commercial, melamine-curing car series clear lacquer on acrylic resin base in one Dry layer thickness of 35 µm overcoated and a) 30 minutes or b) 120 minutes dried at 135 ° C (object temperature).

One obtains the usual requirements in automotive OEM painting fair multi-layer metallic paint.

Furthermore, the waterborne basecoat obtained is applied to a conventional, phosphated and thanks to cathodic dip painting and body panel pre-coated with filler applied by spraying in a wedge (dry layer thickness 0 to 50 µm). This happens by means of a painting machine without intermediate airing. The expiration limit is 30 µm.  

Paint example 4 (comparative example)

Lacquer example 3 is repeated with the difference that instead of the dispersion Production Example 1 The dispersion from Production Example 2 is used. The Drainage limit is 45 µm.

Paint example 5 (according to the invention)

Lacquer example 1 is repeated with the difference that instead of the dispersion Production Example 1 the dispersion from Production Example 3 during production of the red water-based paint is used. The drainage limit of the waterborne basecoat is 45 µm.

Paint example 6 (according to the invention)

Lacquer example 1 is repeated with the difference that instead of the dispersion Production Example 1 the dispersion from Production Example 4 during production of the red water-based paint is used. The drainage limit of the waterborne basecoat is 42 µm.

Paint example 7 (according to the invention)

Lacquer example 3 is repeated with the difference that instead of the dispersion Production Example 1 the dispersion from Production Example 3 during production of the silver water-based paint is used. The expiry date of the Waterborne basecoat is 43 µm.

Paint example 8 (according to the invention)

Lacquer example 3 is repeated with the difference that instead of the dispersion Production Example 1 the dispersion from Production Example 4 during production of the silver water-based paint is used. The expiry date of the  Waterborne basecoat is 39 µm.

The adhesion of the first lacquers obtained in lacquer examples 1a) to 8a) became tested by cross-cutting according to DIN EN-ISO 2409. In addition, the Repair paint conditions simulated with the same paint materials. For this purpose, the unbrushed overbaked first coats 1b) to 8b) again with the same water-based paint / clear coat two-coat system Mistake. The reapplied two-layer structures were 30 minutes each dried at 135 ° C. The refinish paints thus obtained were also tested for adhesion by cross cutting according to DIN EN-ISO 2409.

Table 1 summarizes the cross-cut values obtained.

Table 1

Claims (7)

1. Aqueous coating agent containing an aqueous binder dispersion and optionally one or more organic solvents, crosslinkers, pigments, fillers, customary paint additives and / or one or more other binders, characterized in that the aqueous binder dispersion is based on polyurethane / polymer-polymer hybrids a number average molecular weight (Mn) of 15,000 to 1,500,000, a weight ratio of polyurethane to polymer fraction of 0.05: 1 to 50: 1, with a proportion of polyunsaturated comonomers polymerized into the polymer fraction of the polyurethane / polymer-polymer hybrid from 5 to 45 % By weight, based on the sum of mono- and polyunsaturated comonomers polymerized into the polymer fraction, with a hydroxyl number of 0 to 150 mg KOH / g, based on solid resin, hydroxyl groups bonded to silicon not being included in the calculation of the OH number and an acid number of 1.5 to 60 mg KO H / g, based on solid resin, and a content of 0.5 to 300 mmol silicon per 100 g solid resin in the form of siloxane bridges (-Si-O-Si-) integrated in the polyurethane portion and / or in the form of bound to the polyurethane portion Silanol groups. 2. A process for the preparation of an aqueous coating composition as claimed in claim 1, by preparing an aqueous binder dispersion and optionally mixing with the desired further proportions, as defined in claim 1, characterized in that the aqueous binder dispersion is prepared by transferring a polyurethane prepolymer containing acid groups, which has on average 0.1 to 2 radical copolymerization-accessible olefinically unsaturated groups per molecule and on average 0.7 to 9 R'O groups bonded to silicon per molecule, wherein
R '= C1 to C8 alkyl or C (O) R''', and
R '''= C1 to C10 alkyl
mean, the polyurethane prepolymer optionally dissolved in an isocyanate-inert solvent and its acid groups optionally neutralized beforehand, by adding water to an aqueous dispersion and then free radical polymerization together with one or more mono- and polyunsaturated comonomers. 3. The method according to claim 2, characterized in that the polyurethane prepolymers are prepared by reacting the free isocyanate groups of a polyurethane prepolymer with

• 1. one or more compounds of the general formula
  ((HX-) _n R) _a Si (OR ') _b (R ") _c (I)
  with X = O, S, NH or NR ' ^v , preferably NH or NR' ^v ,
  R = a bifunctional, trifunctional or tetrafunctional, preferably bifunctional organic radical with a molecular weight of 13 to 500,
  R '= C1 to C8 alkyl or C (O) R''',
  R "= R '''= C1 to C10 alkyl, where R" and R''' can be the same or different,
  R ' ^v = C1 to C8 alkyl, a = 1, 2 or 3, b = 1, 2 or 3, c = 0, 1 or 2, n = 1 to 3, where several radicals R', R "and R '''are the same or different and the sum of a plus b plus c is four,
• 2. one or more olefinically unsaturated monomers capable of addition to isocyanate groups,
• 3. optionally one or more NH ₂ - and / or NH groups carrying alkanolamines with an OH functionality of at least 1, and
• 4. optionally one or more aliphatic C4-C36 alcohols and / or amines.

4. Use of the coating agent according to claim 1 or obtained according to claim 2 or 3 for creating a basecoat film, which in a process for Production of multi-layer coatings by applying a basecoat and Clear coat is used on an optionally pretreated substrate. 5. Use according to claim 4, characterized in that the Basecoat layer in a dry layer thickness of 8 to 50 microns created. 6. Use according to one of claims 4 or 5, characterized in that the basecoat is created by a single spray. 7. Use according to claim 4 for the production of multi-layer coatings in the automotive sector.