MXPA99007590A - Aqueous recovery product, its preparation and use for drying enamels - Google Patents

Abstract

The invention relates to an aqueous coating product and its preparation as well as to its use, especially for the production of coatings resistant to chemical agents and resistant to impacts of guijarr

Description

Aqueous coating product, its preparation and use for oven drying enamels Background of the invention: The invention relates to a coating medium and its preparation, as well as its use, especially for the formation of coatings resistant to chemical agents and resistant to the impact of pebbles. For the pebble-resistant coatings in the automobile industry, mostly dissolved organic polyester resins were applied which were baked in the oven with melamine resins or blocked polyisocyanates as a hardener. A process for the preparation of an oven-dried filling filler of this type is described, for example, in DE-A 3 918 510. Modern aqueous binders are in a position to replace binders in many applications. dissolved organic In many applications of this type of enamels, as, for example, in the automotive industry the high requirements have not yet been achieved both for the coating means ready for use and for the resulting coatings. Thus, for example, EP-A 024 727 describes an oven-dried enamel based on a combination of phosphoric acid ester-epoxy resin, a water-dilutable polyester and water-soluble melamine resins. DE-A 4 000 748 describes in exemplary embodiments ref. : 30984 water-based automotive filler primers based on hydroxy-functional polyurethane-polyester resins that can be diluted in water, optionally other binders and water-soluble amine resins. DE-A 3 813 866 describes hydrophilic filler primers of water-dilutable polyurethane resins, polyester of modified epoxy resin, dilutable in water and, optionally, aminoplast resin dilutable in water. The high demands that, especially in the automotive industry, are established for filler coatings are not yet fully achieved with these coatings. Improved polyisocyanate crosslinked coatings achieved an improvement (M. Bock, H. Casselmann, H. Blu "Progress in Develop- ment of Waterborne PUR-Primers for the Automotive Industry", Proc. Waterborne, Higher Solids and P oder Coatings Symp. New Orleans 1994). However, all the systems mentioned have the disadvantage that the polyurethane-polyester resins or the water-dilutable polyester resins used are very sensitive to hydrolysis and thus the systems have a limited storage stability. The high demands regarding resistance to chemical agents can not always be met by these systems. Aqueous dispersions resistant to hydrolysis can be prepared, e.g. , based on copolymers of (meta) acrylic acid esters. Along with improved storage stability, polyacrylates also have a better resistance to chemicals than polyester or polyester-polyurethane. But in the field of pebble-resistant coatings these systems are not applied, since polyester-based or polyester-polyurethane-based enamels clearly outstrip polyacrylates with respect to mechanical properties, especially in elasticity. DE-A 4 332 067 discloses oven drying esters based on polyacrylates prepared in low molecular weight oligoesters. The oligoesters used as reaction medium for the radical polymerization have a low molecular weight of < 1000 g / mol. The advantages resulting from a chemical chaining of polyester and polyacrylate are not described. No indications are given for a suitable polyol composition for elastic coatings resistant to the impacts of pebbles. DE-A 4 427 227 discloses a low yellowing baked enamel composed of a polyacrylate graft polyester and melamine resin dilutable in water and / or hydrophilized polyisocyanate. Here, too, there is no indication of a suitable polyol composition for pebble-resistant coatings., elastic. The aim of the invention is the preparation of storage stable aqueous enamel systems which have an improved resistance to chemical agents with an extraordinary resistance to the impacts of pebbles. Surprisingly it has been found that this objective can be achieved by using a combination of special aqueous polyols and blocked polyisocyanates. The dispersions of polyols used according to the invention are characterized in that they are composed of polyacrylate-polyester base graft copolymers, certain long-chain aliphatic monocarboxylic acids as well as polyester containing unsaturated α, β-carboxylic acids being incorporated as polyester components. . The suitability of the polyol dispersions according to the invention for oven-drying enamels is surprising insofar as the polyols, which contain a high proportion of polyacrylate, in the enamelling by drying in the oven as are used, eg , for the filling priming in automobiles, up to now they do not meet the high demands, eg, on elasticity and impact resistance of pebbles. Accordingly, the object of the invention is an aqueous dispersion of A) a polyol component of from 20 to 60, preferably 40 to 55% by weight of a polyester component AI), characterized in that AI) contains 10 to 60. % by weight of units derived from one or more aliphatic monocarboxylic acids, saturated or unsaturated with 8 to 30 carbon atoms, and also contains 0.4 to 5% units derived from one or more monocarboxylic acids. - eos or dicarboxylic, unsaturated ß, polymerized by radicals with 3 to 8 carbon atoms, or their anhydrides and 40-80%, preferably 45-60% of a polyacrylate component AII) as well as B) a component of polyisocyanate compound of one or more blocked polyisocyanates, preferably not hydrophilized, whereby component B) is present in parts by weight, based on the total content of the dispersion in solids is from 1 to 70, in 20 to 50%. The invention also relates to a process for the preparation of an aqueous dispersion characterized by A) a polyol component of 20-60%, preferably 40-55% of a polyester component AI) with a molecular weight of 500-6000, preferably 1000-3000, an acid number <; 15 KOH / g and an OH number of 50-250 mg KOH / g, preferably 100-180 mg KOH / g, characterized in that AI) is obtained by transformation of AI1} 10-60%, preferably 30-50% of one or more saturated or unsaturated aliphatic monocarboxylic acids with 8-30 carbon atoms, AI2) 0.4-5%, preferably 0.6-2% of a monocarboxylic acid or dicarboxylic a, ß not saturated with 8 carbon atoms or Its anhydrides AI3) 20-60%, preferably 25-40% of one or more di-, tri-, or tetracarboxylic, aliphatic, cycloaliphatic or aromatic acids with 2 to 40 carbon atoms.

Carbon or its anhydrides AI4) 10-60%, preferably 20-50% of one or more aliphatic alcohols with 1-4 OH groups per molecule AI5j 0-10% of a monocarboxylic acid aromatic AI6) 0-10% of other compounds reactive towards COOH or OH as epoxides, isocyanates, amines or oxazolines with 1-4, preferably 1.9-2.5 functional groups nales per molecule and 40 '-80%, preferably 45-65% of a polyacrylate component AII) which can be obtained from a radical polymerization of a mixture of AIII) to 70%, preferably 25-50% of one or several non-functional esters of α, β-unsaturated carboxylic acids with 3-12 carbon atoms and aliphatic or cycloaliphatic monoalcohols with 1-18 carbon atoms AII 2) 1-10%, preferably 2-7% of one or more carboxylic acids a, ß not saturated with 3-12 carbon atoms or their anhydrides AII 3) 0 to 95% of one or more hydroxy-functional monomers, polymerizable by radicals AII4) 0 - 40% of other monomers polymerizable by radicals in the presence of the polyester component AI), whereby the data indicated in AI and AI I are referred to the weight and totalize 100% and finally B) a polyisocyanate component composed of an aliphatic polyisocyanate preferably not hydrophilized, blocked as well as water, optionally organic solvents and optionally customary co-builders being added to the enamels, wherein component B) is present in parts by weight, based on the total solids content of the dispersion, in 1-70%, preferably 20% by weight. - fifty%. Another object of the invention is the use of the enamel prepared in this way for kiln-dried coatings, preferably in automobile enamelling, especially preferably as an oven-dried filler primer. The preparation of the polyol component A) according to the invention is carried out in such a way that the polyester component AI) is first synthesized by the usual processes. The preparation of polyesters AI) is known. As component AI1 (the polyester component of the polyol dispersion according to the invention contains one or more aliphatic monocarboxylic acids with 8-30 carbon atoms Examples of saturated monocarboxylic acids with 8-30 carbon atoms are ethylhexanoic acid, octanoic acid ( caprylic acid), decanoic acid (caprinic acid), dodecanoic acid (lauric acid), hexadecanoic acid (cetyl acid) or octadecanoic acid (stearic acid). Unsaturated aliphatic monocarboxylic acids are also suitable singly or multiply with 8 to 30 carbon atoms. carbon, such as, for example, oleic acid, linolenic acid or linolenic acid, preferably mixtures of monocarboxylic acids, such as those resulting in the saponification of natural oils and fats, Examples of this type of fatty acids are fatty acids of soybean oil, tallow fatty acids, flaxseed oil fatty acids, fatty acids castor oil, coconut oil fatty acids, hazelnut oil fatty acids or safflower oil fatty acids. Other suitable examples of monocarboxylic acids having 8 to 30 carbon atoms are hydrogenated fatty acids, synthetic fatty acids, e.g., paraffin oxidation or Koch synthesis (J. Falbe, New Syntheses with Carbon Monoxide, Berlin, Heidelberg, New York (1980)). Preferably, aliphatic carboxylic acids with less than 2 C = C bonds are applied. Other modules of the polyesters according to the invention are the α, β unsaturated mono and dicarboxylic acids with 3-8 carbon atoms AI2). Examples of such carboxylic acids are acrylic acid, methacrylic acid, taconic acid, maleic acid, fumaric acid or tetrahydrophthalic acid. Instead of the free carboxylic acids, the carboxylic acid derivatives can also be used as, eg, anhydrides or esters as starting substances for the preparation of polyester. Examples of the di-, tri-, or tetracarboxylic, aliphatic, cycloaliphatic or aromatic acids with 2-40 carbon ato-lines AI3) are phthalic acid, isophthalic acid or terephthalic acid, as well as pyromellitic acid, trimellitic acid and succinic acid, adipic acid, sebacic acid and azelaic acid. Dimeric fatty acids made from natural or synthetic fatty acids are equally suitable. Instead of the free carboxylic acids, the carboxylic acid derivatives such as, for example, anhydrides or esters can also be used as starting materials for the preparation of polyester. As OH (Al) components (4) with 1-4 OH groups per molecule, there can be used, for example, aliphatic monoalcohols such as butanol, pentanol or 2-ethylhexanol. Also suitable are "fatty alcohols", such as those formed in the reduction of fatty acids. Examples of alcohol components with 2 OH groups are ethylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, trimethylpentanediol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, tripropylene glycol or the bisphenol hydrate. Preference is given to using as components OH AI4) higher-valent trivalent alcohol components, optionally in combination with divalent alcohols. By way of example, pentaerythritol, glycerin or trimethylolpropane are mentioned. As the monocarboxylic acids AI5), for example, benzoic acid or alkylbenzoic acids are suitable. Usually the preparation of components AI) is carried out by polycondensation as described in the bi-literature (R. Dhein, K. Reuter, G. Ruf in "Houben-Weyl, Me-thoden der Organischen Chemie Bd E20 / 2 ' , Hrsg .: H. Bartl, J. Falbe, 4th edition, pages 1429-1435, Stuttgart, New York (1987), but it is also possible to react with other compounds AI6), compounds reactive towards OH, such as polyisocyanates or compounds reactive towards COOH as the substances containing epoxide, amino or oxazolino groups and thus constitute urethane or amide groups in the polyester As the polyisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, methylene bis (4-isocyanatocyclohexane) are preferably suitable. ), tetramethylxylene diisocyanate or modified aliphatic types such as polyisocyanates containing isocyanurate, uretdione or biuret groups In principle, aromatic polyisocyanates are also suitable as The toluylene diisocyanate or the methylene bis (4-isocyanatobenzene). Suitable epoxides are, for example, epoxy resins based on bisphenol-A-diglycidileter or also Cardura®E 10 (Shell). Suitable amines are, for example, hexamethyldiamine, isophorone diamine, diethylenetriamine, ethylenediamine. The polyacrylate component AII) is prepared according to the process of the invention by means of a radical polymerization in the presence of the polyester component AI). Due to the reaction of the components AII1) - AII4) with the unsaturated α, β-polyester components, a graft copolymerization takes place here. The graft copolymer thus formed has a greater molecular mass and above all a higher suitability than a mixture of polyester and polyacrylate. Together with component AI), organic solvents can be added during the polymerization. Suitable organic solvents are those which are usually used in the preparation of polyacrylate resins and solvents suitable for the preparation of aqueous dispersions. Suitable solvents are: alkylbenzenes such as toluene, xylene or ethylbenzene, alcohols such as __-butanol, iso-propanol, ethylene glycol -monobutylether, diethyl glycol-monobutylether, tripropylene glycol, 3-methyl-3-methoxybutanol or also methoxypropylacetate-2, dipropylene glycol-dimethyl-ether. Acetone, butanone, ethanol, propanol or hexane are also suitable. The solvents used can be removed from the reaction mixture before, during or after the dispersion step, totally or partially, if necessary azeotropically, and / or by subjection to a vacuum or a stream of reinforced inert gas. For radical polymerization, it is possible, for example, to proceed as follows: components AII-j to AII4) are mixed separately or together or also partially at a suitable temperature with component AI) and optionally are metered to a solvent and polymerized there in the presence of a polymerization initiator. As the polymerization initiator, known compounds are used. For example, peroxides such as dibenzoyl peroxide, di-t-butylperoxide or t-butylper-2-ethylhexanoate or else azoinitiators such as azo-bis-isobutyronitrile or azo-bis-isovaleronitrile are suitable. It is also possible to carry out the polymerization in the presence of regulators. These types of compounds that by the transfer of radicals reduce the molecular weight of the polymerized are likewise known. Examples include n-dodecyl mercaptan or mercaptoa-acetic acid. For the attainment of special properties, one or more faster, slower, more premature initiating and / or more terminated monomers may be added later than the other monomers. As the AII-J component, any copolymerizable (cyclo) alkyl ester of (meth) acrylic acid having 1 to 20 carbon atoms in the cycloalkyl radical or a mixture of this type of (meta) acrylic acid esters can be used. Alkyl acrylates or alkyl-methacrylates having 1-18 carbon atoms in the remaining alkyl radical are especially suitable. Examples which may be mentioned are methylacrylate, ethylacrylate, n-propylacrylate, n-butylacrylate, i-butylacrylate, n-hexylacrylate, 2-ethylhexylacrylate, n-esterylacrylate and n-lauryl acrylate and methacrylate as well as (meta) acrylic acid esters cycloaliphatics such as cyclohexyl (meta) acrylate or norbornyl (meta) acrylate. Equally suitable are esters of maleic acid or fumaric acid, such as, for example, dimethyl or diethyl ester of maleic acid or fumaric acid. Examples of carboxylic acids, unsaturated ß AII2) are, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid or tetrahi-drophthalic acid. Instead of the free carboxylic acids, their anhydrides can also be used as starting material. Suitable hydroxy-functional monomers AII3) are preferably all hydroxyalkyl esters or hydroxy-cakyl alkyl esters of the acids mentioned in AII2). These hydroxy-functional esters are obtained particularly preferably by transformation of the (meta) acrylic acid with an alkylene oxide or an aliphatic diol. Suitable are, for example, 2-hydroxyethyl (meta) acrylate, 2-hydroxypropyl (meta) acrylate, 3-hydroxypropyl (meta) acrylate, 4-hydroxybutyl (meta) acrylate or else the (meta) acrylic acid conversion product with monoepoxide, such as, for example, Cardura®E 10. (Shell). Also suitable are esters of (meta) a-crilic acid and oligomeric glycols or polymers of ethylene or propylene. Equally suitable, but less preferred, are the radically polymerizable monomers containing OH groups that do not contain any structure derived from unsaturated a, ß-carboxylic acids. Examples of other polymerizable radical monomers AII4) are, for example, vinylaromatic compounds such as styrene or α-methylstyrene, vinyl esters of carboxylic acids with 1-20 carbon atoms such as versatic acid, propionic acid or acetic acid, vinyl ether , vinylpyrrolidone or compounds with two or more double radical-polymerizable bonds, such as, for example, , butanedioldi (meta) acrylate, hexandiol-di (meta) acrylate, divinylbenzene or polybutadiene. For the preparation of a polyol dispersion according to the invention, the acid groups of the polyester-polyacrylate graft copolymer are then converted into salts. This is preferably carried out by reaction with an amine. Especially tertiary amines such as triethylamine are preferable, N, N-dimethylethanolamine or N, N-dimethylisopropylamine. Neutralization is also possible, eg with metal hydroxides such as potassium hydroxide, sodium or lithium hydroxide or with primary or secondary amines and ammonia. For the transformation of the hydrophilized resin into aqueous dispersion, water is then added to the resin with vigorous stirring. But you can also proceed so that you put the water first and add the hydrophilized resin by stirring. A less preferred method is to dissolve the neutralizing product in the dispersion water and add by stirring the non-hydrophilized resin or arrange the non-hydrophilized resin and add the neutralization amine solution to the water with stirring. The polyol dispersion thus prepared can then be formulated together with crosslinking components to form an enamel. Preferably, blocked polyisocyanates are used as crosslinking components. For the incorporation of the blocked polyisocyanate in the aqueous enamel, it is possible to proceed in such a way that a hydrophilicized blocked polyisocyanate is mixed with the polyol dispersion. A particularly preferred process consists of mixing one or more non-hydrophilized blocked polyisocyanates to the polyacrylic polyester resin before neutralization and co-dispersing this resin mixture as described. Examples of suitable polyisocyanates based on the blocked polyisocyanates are cycloaliphatic or aliphatic polyisocyanates such as tetramethylene diisocyanate, cyclohexane-1-3- and 1-4-diisocyanate, hexamethylene diisocyanate (HDI), 1-isocyanate-3, 3, 5-trimethyl-5 isocyanatomethyl-cyclohexane (isophorone diisocyanate, IPDI), methylene-bis- (4-isocyanatocyclohexane), tetramethylxylylenediisocyanate (TMDXDI). In addition, aromatic polyisocyanates such as toluylene diisocyanate (TDI), diphenylmethane-2,4'-diisocyanate and / or 4,4'-diisocyanate, triphenylmethane 4,4'-diisocyanate, naph ilen-1, and the like are also suitable in principle. -diisocyanate. Especially suitable are polyisocyanates containing heteroatoms in the isocyanate group-containing moiety. Examples of this are polyisocyanates having carbodiimide groups, allophanate groups, isocyanourate groups, urethane groups and biuret groups. Particularly well suited for the invention are the known polyisocyanates which are used in particular in the preparation of enamels, for example, the modification products having isocyanurate, biuret or uretdione groups of the above-mentioned simple polyisocyanates, in particular hexamethylene diisocyanate or isophorone diisocyanate . Also suitable are low molecular weight polyisocyanates containing urethane groups, such as those obtainable by transformation of IPDI or TDI excessively added with simple alcohols or polyvalenols of molecular weight range of 62-300, especially with trimethylolpropane or glycerin. It is of course also possible to use any other mixture of the polyisocyanates mentioned for the preparation of the products according to the invention. Suitable polyisocyanates are also the known prepolymers which have terminal isocyanate groups, such as those obtainable, in particular, by conversion of the above-mentioned simple polyaryates, especially the diisocyanates, with defective amounts of organic compounds having at least two functional groups of isocyanates reactive with respect to isocyanates. In these known prepolymers the proportion of isocyanate groups relative to the hydrogen atoms reactive towards NCO corresponds from 1.05: 1 to 10: 1, preferably from 1.1: 1 to 3: 1, the hydrogen atoms preferably coming from hydroxyl groups. The type and the quantitative proportion of the starting materials used in the preparation of NCO polymers is usually preferably chosen in such a way that the NCO prepolymers preferably have an average NCO functionality of 2 to 3 and a mass mean number molecular 500 - 10,000, preferably 800-4000. The isocyanate groups of the polyisocyanate are completely blocked. As the blocking agent, customary compounds such as those used, for example, in the enamel sector, can be used. Examples of suitable blocking agents are maleic acid dimethyl ester, maleic acid diethyl ester, acetoacetic acid ethyl ester, e-caprolactam, acetanilide, secondary aliphatic amines and / or acetonoxime. Preference is given to using butanone oxime, 3,5-di-ethylpyrazole or triazole. The blocking of the polyisocyanate can be effected, for example by heating one or more polyisocyanates with the blocking agent. For example, one or more polyisocyanates can be arranged and heated by stirring, eg, at about 80 ° C, and adding the blocking product (for example, for about 10 min.). It is stirred all the time until no trace of free isocyanate can be found. It is also possible to block one or more polyisocyanates with a mixture of two or more blocking products. Preferably the blocked polyisocyanates described are not hydrophilically adjusted and the transformation in the aqueous dispersion is carried out by mixing and dispersion together with the polyol resin melt. However, it is also possible to disperse only the polyol and to add to the aqueous phase a solution or dispersion of a blocked hydrophilic polyisocyanate. Hydrophilized blocked polyisocyanates are known (eg, EP-A 566 953). The oven-dried enamels of the blocked polyols and isocyanates according to the invention can be combined with other binders. Preferred is the combination with water-soluble or insoluble melamine resins as well as polyester resins or emulsifiable or water-dispersible polyurethane-polyester resins. For the production of oven-dried enamels, customary additives (for example, pigments, fillers, coadjuvants and other additives) can be added as are customary in the enamelling sector. The quantities are usually found in familiar intervals for a person skilled in the art. The use according to the invention is the preparation of oven-drying enamels, preferably in the glazing of automobiles, with particular preference for the preparation of filling primer layers resistant to pebble impacts. In this, the coating means used according to the invention can be applied by spraying, dipping, application by injection, as injection by compressed air or without air, as well as electrostatic supply, for example, supply by high-speed rotating bell.

The dry film layer thickness can be, e.g. , from 10-80 μm. The drying conditions of the oven drying enamels according to the invention depend on the nature of the blocking agent selected from component B). In general, temperatures are 80 - 200 ° C. Preferably it is a constant temperature for 10-30 minutes. The preferred oven drying range is about 135-170 ° C for about 20 minutes. The enamel prepared from the dispersions according to the invention have a very high storage stability. The chemical decomposition by cleavage of the ester linkages which usually take place in the storage of the aqueous polyester dispersions or solutions and of the polyester-polyurethane dispersions is not observed in the polyester-polyacrylate dispersions according to the invention. At the same time, the prepared enamels of the dispersions according to the invention have an extraordinary resistance to the impact of pebbles which could only be established for current aqueous solutions by systems based on polyester dispersions.

Examples Example 1 - Polyester resin In a reaction vessel with mixing, cooling and heating device as well as with water separator, 4041 g of hazelnut oil fatty acid, 4350 g of trimethylolpropane, 1131 g of trimethylene glycol, 99 g of maleic anhydride, 2035 g of phthalic anhydride and 2008 g of adipic acid. Nitrogen is passed through the reaction mixture. The compound is heated in 4 hours at 185 ° C. After 2 hours at 185 ° C, it is then heated for a further 2 h at 220 ° C. At this temperature a more intense stream of nitrogen (ca. 30 1 / hr) is conducted through the assembly until the acid number has dropped to 9 mg KOH / g. The OH number is 196 mg KOH / g. Example 2 - Polyester-polyacrylate resin In a 6 1 four-necked flask with internal thermometer, mixing device, dropping funnel, gas conduit and reflux condenser, 500 g of the polyester intermediate of the example are incorporated under a nitrogen atmosphere. 1 and 33.4 g of butyl diglycol (diethylene glycol mononobutyl ether). A monomer mixture of 75 g of hydroxyethyl methacrylate, 56 g of butyl-crilate, 271 g of methyl methacrylate and 50 g of styrene is prepared in the dropping funnel. At a temperature of 145 ° C, half of the monomer mixture is added over the course of 3 hours. Parallel to this, a solution of 10 g of di-t-butylperoxide in 40 g of butyl diglycol is added. Then 48 g of acrylic acid is added and mixed to the rest of the monomer mixture. The second monomer mixture prepared in this way is then added over the course of 1.5 hours. Parallel to this, a solution of 5 g of di-t-butylperoxide is added to 20 g of butyl diglycol. Subsequently, a solution of 5 g of di-t-butyl peroxide in 20 g of butyl diglycol is also added for reactivation.

Example 3 - Blocked Polyisocyanate In a 2-liter four-necked flask with reflux condenser, inner thermometer and stirrer, 600 g of Desmodur® L67 (aromatic polyisocyanate based on toluylene diisocyanate, 67% dissolved in 1-methoxypropyl acetoacetate) are heated. 2 / xylene (1: 1), isocyanate content 11.5%) at 65 ° C. Subsequently, 143 g of butanonoxim are added in drops for one hour. It is stirred all the time until no band of isocyanates is detected in the infrared spectrum. Example 4 - Self-crosslinking polyester-polyacrylate dispersion In a 6 1 four-necked flask with internal thermometer, mixing device, gas line and reflux condenser, 1108 g of the homogenizer are homogenized at 70 ° C in a nitrogen atmosphere. polyester-polyacrylate intermediate of Example 2 and 669 g of the blocked isocyanate of Example 3. 64 g of N, N-dimethylethanolamine are added and the mixture is stirred for 30 minutes. Then 1315 g of water are added. The product is a milky aqueous dispersion with an average particle size of 295 nm (determined by laser correlation spectroscopy), a viscosity of 1500 mPa · s and a nonvolatile part of 40.0%.

Example 5 - Dispersion of self-crosslinking polyester-polyacrylate In a 4-liter four-necked flask with internal thermometer, mixing device, gas line and reflux condenser, 600 g of the intermediate of the intermediate is homogenized at 70 ° C under a nitrogen atmosphere. polyester-polyacri -late of Example 2 and 613 g of Desmodur® BL 3175 (hexamethylene-diisocyanate-based crosslinking urethane resin dissolved in 75% in Solventnafta 100) at 70 ° C. 61 g of N, N-dimethylethanolamine are added and the mixture is stirred for 30 minutes. Then 1153 g of water are added. The product is a milky aqueous dispersion with an average particle size of 213 nm (determined by laser correlation spectroscopy), a viscosity of 3574 mPa-s and a non-volatile part of 43.2%.

Example 6 - Oven-drying enamel of the self-crosslinking polyester-polyacrylate dispersion of Example 4 45.18 g of a pigmented paste, which has been milled for 30 minutes in a commercially available bead mill, composed of 12, 56 g of 42% polyester-polyurethane dispersion, 9.6 g of distilled water, 1 g of butyl diglycol, 0.15 g of antifoam (Bayer, DNE Antifoam), 0.43 g of commercially available wetting agent, 14.72 g of titanium dioxide (Bayertitan R-KB-4), 0.14 g of black iron oxide (Bayferrox 303 T), 4.05 g of barium sulfate (Blanc fixe Micro, Sachatleben GmbH), 2 , 7 g of talc (Micro Tale IT Extra, Norwegian Tale) and 0.41 g of anti-deposition product (Aerosil R 972, Degussa) are stirred with 49.1 g of the 40% polyester-polyacrylate dispersion of the example. 4 and 5.2 g of a commercially available aqueous blocked polyisocyanate (Bayhydur BL 5140) as well as 0.6 g of commercially available base wetting product and diluted with distilled water. ilada to a viscosity of injection of cup Ford DIN of 4 mm of about 22 s. This enamel is applied by means of a fluidization cup injection gun with a nozzle of 1.5 mm diameter and a spray pressure of 5 bar on the substrate below with a resulting dry film thickness of 25-35 μm. Example 7 - Oven-drying enamel of the self-crosslinking polyester-polyacrylate dispersion of Example 5 45.18 g of a pigmented paste, which has been milled for 30 minutes in a commercially available bead mill, composed of 12, 56 g of 42% polyester-polyurethane dispersion, 9.6 g of distilled water, 1 g of butyl diglycol, 0.15 g of antifoam (Bayer, DNE Antifoam), 0.43 g of commercially available wetting agent, 14.72 g of titanium dioxide (Bayertitan R-KB-4), 0.14 g of black iron oxide (Bayferrox 303 T), 4.05 g of barium sulfate (Blanc fixe Micro, Sachatleben GmbH), 2 , 7 g of talc (Micro Tale IT Extra, Norwegian Tale) and 0.41 g of anti-deposition product (Aerosil R 972, Degussa) are stirred with 45.65 g of the 43% polyester-polyacrylate dispersion of Example 5 and 5.2 g of a commercially available aqueous blocked polyisocyanate (Bayhydur BL 5140) as well as 0.6 g of commercially available base wetting agent and are diluted with distilled water. At a viscosity of injected Ford Cup DIN 4 mm of about 20-22 s. This enamel is applied by means of a fluidization cup injection gun with a nozzle of 1.5 mm diameter and a spray pressure of 5 bar on the substrate below with a resulting film thickness of 25-35 μm. The wet enamel films of Examples 6 and 7 are ventilated for 5 minutes at 23 ° C and then oven dried in a forced circulation oven. The substrates in the case of pendulum hardness and brightness tests are glass plates; in the case of pebble impact tests, they are steel plates coated with KTL, such as those used in the production of automobiles.

Results of the tests: The results of the following tests were obtained after cross-linking at 140 ° C (first value) and 160 ° C (second value); duration of drying in the oven 30 minutes in each case.

Pendular hardness; oscillation test according to Konig DIN 53 157 Measurement of gloss according to Gardner 60 ° Test of impact of pebbles VDA according to the Specification VW 2 sometimes 500 g steel shot released with compressed air at 1.5 bar pressure. index 1 - 10 (1 = no impact signal, 10 = many crushes and very large sheet) VDA pebble impact test according to Specification VW with ESP 10 perk impact test device from Byk at 3 bar test pressure. Determination of the separation plane in mm of the steel sheet.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (12)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. Cachactad aqueous dispersion because it consists of A) a polyol component A) composed of 20-60% by weight of a polyester component AI) , characterized in that AI) contains 10-60% by weight of units that are derived from one or more aliphatic monocarboxylic acids, saturated or unsaturated with 8-30 carbon atoms, also contains 0.4 - 5% of units that are derived of one or more unsaturated, unsaturated monocarboxylic or dicarboxylic acids, polymerized by radicals with 3-8 carbon atoms, or of their anhydrides and 40-80% of a polyacrylate component AII) as well as B) of a polyisocyanate component composed of one or more aliphatic blocked polyisocyanates, wherein component B) in parts by weight, based on the total content of the solid dispersion, is 1-70%.
2. 2. Aqueous dispersion according to claim 1, characterized in that it consists of: A) a polyol component of 20-60% of a polyester component AI) with a molecular weight of 500 - 6000, an acid number < 12 KOH / g and an OH number of 50-250 mg KOH / g, characterized in that AI) can be obtained by transformation of AI1} 10-60% of one or more saturated or unsaturated aliphatic monocarboxylic acids with 8-30 carbon atoms, AI 2) 0.4-5% of a monocarboxylic acid or unsaturated dicarboxylic or unsaturated acids with 3-8 carbon atoms carbon or its anhydrides AI 3) 20-60% of one or more di-, tri-, or tetracarboxylic, aliphatic, cycloaliphatic or aromatic acids with 2-20 carbon atoms or their anhydrides, AI 4) 10-60% of one or several aliphatic alcohols with 1 to 4 OH groups per molecule, AI 5) 0-10% of an aromatic monocarboxylic acid AI 6) 0-10% of other compounds reactive towards acid or OH, such as, for example, epoxides, isocyanates or oxazolines with 1-4, preferably 1.9 to 2.5 functional groups per molecule, as well as - 80% of a polyacrylate component AII) obtainable from a radical polymerization of a mixture of AII1) 20-70% of one or more non-functional esters of unsaturated α, β-carboxylic acids with 3-12 carbon atoms and aliphatic or cycloaliphatic monoalcohols with 1-18 carbon atoms, AII 2) 1-10% of one or more carboxylic acids, unsaturated β with 3-12 carbon atoms or their anhydrides, AII 3) 0-95% of one or more hydroxy-functional, radical-polymerizable monomers, AII 4) 0-20% of other radically polymerizable monomers, in the presence of the polyester component AI), whereby the data indicated in AI and AII are weight-related and total 100%, as well as B) a component of polyisocyanate compu this of a polyisocyanate preferably not hydrophilized, blocked, whereby component B) is present in parts by weight, based on the total solids content of the dispersion, in 1-70%. Process for the preparation of an aqueous dispersion according to claim 1, characterized by A) a polyol component of 20-60% of a polyester component AI) with a molecular weight of 500 - 6000, an acid number < 12 KOH / g and an OH number of 50-250 mg KOH / g, characterized in that AI) is obtained by transformation of AI1} 10-60% of one or more saturated or unsaturated aliphatic monocarboxylic acids with 8-30 carbon atoms, AI 2) 0.4-5% of a monocarboxylic acid or dicarboxylic acid a, ß not saturated with 3 - 8 carbon atoms or their anhydrides AI, 60% of one or more di-, tri-, or tetracarboxyl, aliphatic, cycloaliphatic or aromatic acids with 2-20 carbon atoms and their anhydrides, AI 4) 10-60% of one or several aliphatic alcohols with 1 to 4 OH groups per molecule, AI 5) 0-10% of an aromatic monocarboxylic acid AI 6) 0 - 10% of other compounds reactive towards acid or OH as, eg, epoxides, isocyanates or oxazolines with 1-4, preferably 1.9 to 2.5 functional groups per molecule, and 40-80% of a polyacrylate component AII) obtainable from a radical polymerization of a mixture of AHi, 20-70% of one or more nonfunctional esters of α, β-unsaturated acids with 3-12 carbon atoms and aliphatic or cycloaliphatic monoalcohols with 1-18 carbon atoms, AII 2) 1-10 % of one or more α, β-unsaturated carboxylic acids with 3-12 carbon atoms or their anhydrides, AII- 0-95% of one or more hydroxy-functional, radical-polymerizable monomers, AII4) 0-20% of others radically polymerizable monomers, in the presence of the polyester component AI), whereby the data indicated in AI and AII are weight-related and total 100%, and finally B) a polyisocyanate component composed of a blocked polyisocyanate as well as water , which eventually and organic solvents and optionally customary co-builders are added to the enamels, whereby component B) is present in parts by weight, based on the total solids content of the dispersion, in 1-70%. Process for the preparation of an aqueous dispersion according to claim 1, characterized in that the polyisocyanate component B) is a non-hydrophilicized polyisocyanate and is dispersed together with the polyol component A). Process for the preparation of an aqueous dispersion according to claim 1, characterized in that the polyol component A) is constituted by 40-55% by the polyester component AI) with a molecular weight of 500 - 6000. 6 Process for the preparation of an aqueous die dispersion according to claim 1, characterized in that the polyol component A) is constituted by 40-55% by the polyester component AI) with a molecular weight of 1000-3000. the preparation of an aqueous dispersion according to claim 1, characterized in that the polyol component A) contains 30-50% of modules of one or more aliphatic monocarboxylic acids AI ^ with 8-30 carbon atoms. 8. Process for the preparation of an aqueous dispersion according to claim 1, characterized in that AI1} is a mixture that is composed of 80-100% aliphatic monocarboxylic acids with 12-20 carbon atoms and less than two C = C double bonds per molecule. 9. Process for the preparation of an aqueous dispersion according to claim 1, characterized in that the polyacrylate component is polymerized in two parts, the first part having an acid number lower than 10 mg KoH / g and the second part an index of acidity higher than 20 mg KOH / g. 10. Use of an aqueous dispersion according to claim 1 for elastic enamel drying in the oven with high elasticity. 11. Use of an aqueous dispersion according to claim 1 for elastic filler priming layers in the automotive series coating. 12. Use of an aqueous dispersion according to claim 1 for filler primer layers in the automotive series coating in combination with 2-15% of one or more water-dispersible melamine resins or blocked hydrophilized polyisocyanates and / or 2 - 30% of a polyester or polyurethane-polyester resin dilutable in water, the indicated data being referred to the weight of the solids part.