MXPA99007588A - Use of an aqueous agglutinant combination for the preparation of fis drying layers - Google Patents

Abstract

The present invention relates to: The invention relates to the use of an aqueous binder combination for the production of a physically fast-drying layer that is at the same time resistant to pebbles and stable to exposure to the elements, preferably when painting in car series

Description

Use of an aqueous binder combination for the preparation of physical drying layers BACKGROUND OF THE INVENTION: The invention relates to the use of an aqueous binder combination for the production of a physically fast-drying layer that is at the same time resistant to pebbles and stable to weathering, preferably in series painting. Of automobiles. In the series painting of automobiles, a configuration of the coating layers has been established, which is also carried out by aqueous coating means. In this, for the modern coatings of this type have also established requirements to the profitability. The objective is to apply the coating with the minimum of individual phases and as cheap as possible. In the configuration of the usual painting in the initial painting of the car, on a metal surface with primer, by means of a cathodic dip coating (KTL), first apply a layer of protection against the impact of pebbles and a layer of primer of filling or a combination of both ("Coating primer for pebble impact protection"). On these layers a pigmented base enamel is then applied and then a colorless enamel or alternatively a pigmented coating enamel. The protection against impact of pebbles and / or the primer layer of impact protection filler REF. 30980 of pebbles provides compensation for flatness of the outer surface and provides a high resistance to pebble impacts due to high elasticity and deformability. Polyester or soft polyester-polyurethane as well as polyisocyanate or melamine crosslinkers have been used for this layer. Before the application of the base enamel and the transparent enamel or the coating enamel, the pebble impact protection priming primer is baked. This is necessary to improve the level of the coating enamel and to smooth the primer layer prior to the application of the top enamel layers. After the application of the transparent enamel and the coating enamel it is dried again in the oven. In this process it is disadvantageous that two expensive kiln drying processes are necessary. Physically, that is, without the oven drying process, fast-drying enamels, such as, for example, those that can be formulated with polyacrylates, do not have the required resistance to the impacts of pebbles, since these in the drying process baked into the oven reticulate too fragile films. The aim of the present invention was to find a binder substance of storage stability which, together with a good pebble impact resistance, would guarantee rapid physical drying. At the same time, the binder had to be solid to light, in the case of coating or base enamels of a medium coating or at points where a coating or pigment base enamel is renounced, producing a stable coating to the exposure to the weather. Thus, an aqueous coating product was sought which combines the essential properties of a primer layer of pebble impact protection and of a coating enamel binder, and which additionally dries physically fast. A solution proposal for coatings and / or primer layers based on aqueous binder is described, for example, in EP-A 3301139. It is claimed that a functional polyester OH and COOH can be added a polyacrylate. No corresponding execution example is described. A graft copolymerization of the polyacrylate in a polyester is not described as a graft base layer. The claimed dispersions of functional polyester-acid are of poor storage stability and are therefore known to be subject to rapid chemical decomposition by dissociation of ester linkages (eg, Jones, TE:; McCarthy, JM). , J. Coatings Technol. 76 (844), page 57 (1995) Surprisingly it has now been found that this objective can be achieved by using a combination of special aqueous polyols and blocked polyisocyanates The polydispersions employed according to the invention are characterized - curly because they are composed of copolymerized polyacrylate-polyester base grafts, certain long chain aliphatic monocarboxylic acids as well as polyester containing unsaturated carboxylic acids a, b being incorporated as polyester components. The suitability of the polyol dispersions used according to the invention is surprising insofar as the polyols, which contain a high proportion of polyacrylate, in the oven-dried enamel like those applied, eg for the Filler primers in automobiles do not meet the high demands, for example, on elasticity and impact resistance of pebbles. Accordingly, the object of the invention is the use of an aqueous dispersion of A) a polyol component of 20 to 60%, preferably 40 to 55% by weight of a polyol component AI), characterized in that AI) contains 10 to 60% by weight of units deriving from one or more aliphatic monocarboxylic acids, saturated or unsaturated with 8 to 30 carbon atoms, also contains 0.4 to 5% units that are derived from one or more monocarboxylic or dicarboxylic acids a, b unsaturated, polymerized by radicals with 3 to 8 carbon atoms, or their anhydrides and 40 to 80% of a polyacrylate component AII) asx as B) a polyisocyanate component composed of one or more blocked aliphatic polyisocyanates, preferably not hydrophilized, whereby component B) in parts by weight, based on the total content of the solid dispersion is from 1 to 70, preferably 20 to 50%. for light-resistant, elastic and physically fast drying coatings for automotive painting. For the use according to the invention, an aqueous dispersion of A) a polyol component of 20 to 60% of a polyester component AI) with a molecular weight of 500 to 6000, an acid number < 12 KOH / g and an OH number of 50 to 250 mg KOH / g, characterized in that AI) can be obtained by transformation of AIU 10 to 60% of one or more saturated or unsaturated aliphatic monocarboxylic acids with 8 to 30 carbon atoms AI2 ) 0.4 to 5% of a monocarboxylic or dicarboxylic acid a, b not saturated with 8 carbon atoms or their anhydrides AI3-,), 20 to 60% of one or more bi-, tri-, or tetracarboxylic, aliphatic, cycloaliphatic or aromatic acids with 2 to 20 carbon atoms or their anhydrides AI 4) 10 to 60% of one or more alcohols aliphatics with 1 to 4 OH groups per molecule AI 5) 0 to 10% of an aromatic monocarboxylic acid AI, 0 to 10% of another compound reactive towards acid or OH, such as, eg, epoxides, isocyanates or oxazolines with 1 to 4, preferably 1.9 to 2.5 functional groups per molecule as well as 40 to 80% of a polyacrylate component AII) that can be obtained from a radical polymerization of a mixture of AIIU 20 to 70% of one or several non-functional esters of carboxylic acids a, b not saturated with 3 to 12 carbon atoms and monoalcohols aliphatic or cycloaliphatic with 1 to 18 carbon atoms AII2) 1 to 10% of one or more carboxylic acids a, b unsaturated with 3 to 12 carbon atoms or their anhydrides AII3) 0 to 95% of one or more monomers h Hydroxyfunctional, radically polymerizable AII4) Or 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 polyisocyanate component composed of a non-hydrophilic, blocked aliphatic polyisocyanate, whereby component B) is present in parts by weight, based on the total solids content of the dispersion, in 1 to 70%. 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 (see below). As component AIn, the polyester component of the polyol dispersion according to the invention contains one or more aliphatic monocarboxylic acids having 8 to 30 carbon atoms. Examples of monocarboxylic acids saturated with 8 to 30 carbon atoms are 2-ethyl hexanoic acid, octanoic acid (caprylic acid), decanoic acid (capric acid), dodecanoic acid (lauric acid), hexadecanoic acid (cetyl acid) or octadecanoic acid (stearic acid). Aliphatic monocarboxylic acids are also suitable single or multiple saturated with 8 to 30 carbon atoms such as, for example, oleic acid, linoleic acid or linolenic acid. Preference is given to using mixtures of monocarboxylic acids, such as those resulting in the saponification of natural oils and fats. Examples of this type of fatty acids are soybean oil fatty acids, tallow fatty acids, flaxseed oil fatty acids, castor oil fatty acids, coconut oil fatty acids, hazelnut oil fatty acids or fatty acids of safflower oil. Other suitable examples of monocarboxylic acids with 8 to 30 carbon atoms are hydrogenated fatty acids, synthetic fatty acids, pej, paraffin oxidation or the Koch synthesis (J. Falbe, New Syntheses with Carbon Monoxide, Berlin, Heidelberg, New York (1980)). Other modules of the polyesters used according to the invention are mono- and dicarboxylic acids a, b not saturated with 3 to 8 carbon atoms AI2). Examples of such carboxylic acids are acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid or tetrahydrophthalic acid. 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. Examples of di-, tri-, or tetracarboxyl, aliphatic, cycloaliphatic or aromatic acids with 2 to 20 ato- carbon dioxide AI3) are thiazolic acid, isophthalic acid or terephthalic acid, as well as pyrometallic acid, trimellic acid and succxnic 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 the OH AI4 components) with 1 to 4 OH groups per molecule, it is possible to use, 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. Preferably, higher-valent trivalent alcohol components, optionally in combination with divalent alcohols, are used as OH-OH components. By way of example, pentaerythria, glycerin or trimethylolpropane are mentioned. As monocarboxylic acids AI5) are, for example, benzoic acid or alkylbenzoic acids. Usually the preparation of components AI) is carried out by polycondensation as described in the bi- bliografxa (R. Dhein, K. Reuter, G. Ruf in "Houben-Weyl, Me-thoden der Organischen Chemie Bd E20 / 2 ', Hrsg.: H. Bartl, J. Falbe, 4th edition, pp. 1429 - 1435 , Stuttgart, New York (1987), but it is also possible to further react with other compounds AI6), compounds reactive towards OH, such as polyisocyanates or compounds reactive with COOH as the substances containing epoxide, amino or oxazolino groups and thus constituting urethane or amido groups in the polyester As the polyisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, methylene bis (4-isocyanatocyclohexane), tetramethyl xylene diisocyanate or modified aliphatic types such as polyisocyanates containing groups are suitable. In principle, aromatic polyisocyanates such as 1-tolylene-diisocyanate or methylene-bis (4-isocyanatobenzene) are also suitable, eg epoxid resins based on bi-ethylene. sphenol -A-diglycidileter or also Cardura®E 10 (Shell). The AID polyacrylate component is prepared for the application according to the invention by means of a radical polymerization in the presence of the polyester component AI). 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. As suitable solvents will be mentioned: alkylbenzenes such as toluene, xylene or ethylbenzene, alcohols such as n-butanol, isopropanol, ethylene glycol -monobutylether, diethyl glycol-monobutylether, tripropylene glycol, 3-methyl-3-methoxybutanol or also l-methoxypropyl acetate-2, dipropylene glycol -dimethylene -ter. 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, in whole or in part, optionally azeotropically, and / or by being subjected to a vacuum or a stream of reinforced inert gas. For radical polymerization, it is possible, for example, to proceed as follows: the components AIIp to AII4) are mixed separately or together or partially at a suitable temperature with the component AI) and optionally are dosed to a solvent and it polymerizes there in the presence of a polymerization initiator. As the polymerization initiator, known compounds are used. For example, peroxides such as dibenzoxyl peroxide, di-t-butylperoxide or t-butylper-2-ethylhexanoate or else azo initiators 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 polymerized are likewise known. Examples include n-dodecyl mercaptan or mercaptoacetic 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 an AIID component you can use any (cyclo) copolymerizable alkyl ester of (meta) acrylic acid with 1 to 20 carbon atoms in the cycloalkyl moiety or a mixture of this type of esters of (meta) acrylic acid. Alkyl acrylates or alkyl methacrylates with 1 to 18 carbon atoms in the alkyl radical are especially suitable. Examples which may be mentioned are methylacrylate, ethylacrylate, n-butylacrylate, 2-ethylhexylacrylate, n-esterylacrylate and n-lauryl acrylate and methacrylate as well as cycloaliphatic (meta) acrylic acid esters 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 unsaturated carboxylic acids a, b A II 2) are, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid or tetrahydrophthalic acid. Instead of the free carboxylic acids, their anhydrides can also be used as starting material. Suitable hydroxy-functional AII3 monomers are preferably all hydroxyalkyl esters or hydroxy-chloalkyl esters of the acids mentioned in AII2). These esters hydroxy-functional products are obtained particularly preferably by transformation of the (meta) acrylic acid with an alkylene oxide or an aliphatic diol. Suitable, for example, are 2-hydroxyethyl (metha) acrylate, 2-hydroxypropyl (metha) acrylate, 3-hydroxypropyl (meta) acrylate, 4-hydroxybutyl (meta) acrylate or else the acid conversion product ( meta) acrylic with monoepoxide such as, for example, Cardura®E 10. (Shell). Also suitable are esters of (meta) acrylic 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 carboxylic acids a, b. Examples of other monomers polymerizable by radicals AII4) are, for example, vinylaromatic compounds such as styrene or α-methylstyrene, vinyl esters of carboxylic acids with 1 to 20 carbon atoms such as versatic acid, propionic acid or acetic acid, vinyl ether , vinylpyrrolidone or compounds with two or more double radical-polymerizable linkages such as, for example, butandioldi (meta) acrylate, hexandioldi (meta) acrylate, divinylbenzene or polybuta-diene. 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 done by reaction with an amine. Especially preferred are tertiary amines such as triethylamine, N, N-dimethylethanolamine or N, N-dimethylisopropylamine. It is also possible to neutralize, for example, with metal hydroxides such as potassium, 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 blocked hydrophilic polyisocyanate is mixed with the polyolemon dispersion. A particularly preferred process consists of mixing one or more blocked polyisocyanates not hydrophilized to the polyacrylic polyester resin before neutralization and dispersing together this resin mixture as described. Examples of suitable polyisocyanates based on the blocked polyisocyanates are the cycloaliphatic or aliphatic polyisocyanates such as tetramethylene diisocyanate, cyclohexane-1-3- and 1-4 -diisocyanate, hexamethylene diisocyanate (HDI), l-isocyanato-3, 3, 5-trimethyl-5- isocyanatomethyl-clohexane (isophorone diisocyanate, IPDI), methylene-bis- (4-isocyanatocyclohexane), tetramethylxylylenediisocyanate (TMDXDI). Polyisocyanates containing heteroatoms in the residue containing isocyanate groups are preferably suitable. Examples of this are polyisocyanates having carbodiimide groups, allophanate groups, isocyanourate groups, urethane groups and biuret groups. Especially suitable 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 polyisocyanates containing urethane groups of low molecular number, such as those obtainable by transformation of IPDI or TDI excessively added with simple or polyvalent alcohols with molecular weight range from 62 to 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 polyacyanates, in particular the diisocyanates, with defective amounts of organic compounds having at least two functional groups of isocyanates with a capacity of opposite reaction. 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 numerical molecular mass. average of 500 to 10000, preferably 800 to 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, acetinylide, secondary aliphatic amines and / or acetone oxime. Preference is given to using butanone oxime, 3,5-dimethylpyrazole 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 described blocked polyisocyanates are not hydrophilically adjusted and the transformation into 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 and described, for example, in EP-A 566 953. The aqueous binders used according to the invention can be combined with other binding agents. 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 preparation of enamels you can add the usual additives (eg, pigments, fillers, adjuvants) and other additives) such as those that are usual in the enamel sector. The quantities are in the usual ranges known by the specialists. The use according to the invention is the preparation of enamels hardened in the furnace physically at low temperature, preferably in the first enameling of automobiles, with special preference for the preparation of peel-resistant impact-resistant closing layers. In this, the coating means used for the use 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, contribution by high-speed rotating bell . The dry film layer thickness can be, for example, from 15 to 50 μm. It is advantageous if the binder according to the invention is first dried at a low temperature, for example at 80 ° C, at which the enamel layer can be polished. After over-enamelling with a basecoat / colorless enamel or with a pigmented coating enamel, the closure layer is dried in a kiln-dried phase together with the colorless enamel or coating enamel. This phase is carried out, for example, by drying in the oven in 20 to 25 minutes at 135 to 145 ° C. The layer thus produced presents, from the optical as well as the mechanical point of view, results comparable to an enamel configuration for which instead of the aqueous closing layer they have been applied as is usual an aqueous filler or solvent-containing primer layer, eg, with 25 to 40 μm dry film layer thickness with a proprietary oven-drying process, eg, 20 to 25 minutes a 135 to 165 ° C and additionally enamel base / colorless enamel or also enamel coating. The coating means used according to the invention have a very high storage stability. The chemical decomposition by cleavage of ester linkages that usually occur very rapidly in aqueous polyester dispersions or solutions and in polyester-polyurethane dispersions is not observed in the polyester-acrylate dispersions according to the invention. At the same time, the enamels prepared with 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 or polyurethane dispersions.

Examples 1 - Polyester resin In a reaction vessel with mixing device, cooling and heating as well as with water separator are weighed 4041 g of hazelnut oil fatty acid, 4350 g of trimethylolpropane, 1131 g of trimethylene glycol, 99 g of maleic anhydride, 2035 g of phthalanhydride 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-neck flask with internal thermometer, mixing device, drip funnel, gas conduction and return cooler, 500 g of the polyester pre-phase are introduced under a nitrogen atmosphere. of Example 1 and 33.4 g of butyl diglycol (diethylene glycol monobutyl ether). A monomer mixture of 75 g of hydroxyethyl methacrylate, 56 g of butylacrylate, 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 is added to 40 g of Butyl diglycol Then 48 g of acrylic acid is added and mixed to the remainder of the monomer mixture. The second monomer mixture thus prepared is then added over the course of 1.5 hours. Parallel to this, a solution of 5 g of di- -butylperoxide is added to 20 g of butyl diglycol. A solution of 5 g of di-t-butylperoxide to 20 g of butyl diglycol is then added to reactivation. Example 3 - Dispersion of self-crosslinking polyester-polyacrylate In a 4-liter four-necked flask with an internal thermometer, mixing device, gas conduction and return cooler, 600 g of the preliminary phase of the reaction are homogenized at 70 ° C in a nitrogen atmosphere. polyester-polya-crilato of example 2 and 613 g of Desmodur® BL 3175 (hexamethi-lendiisocyanate base-curing urethane resin, dissolved at 75% in Solventnaphta 100). 61 g of N, N-dimethylethanolamine are added and the mixture is stirred for 30 minutes. 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%. On a glass plate a polyester-polyacrylate dispersion film with a film thickness of 210 nm is applied and dried for 10 min at room temperature. Then he submits another 30 min to forced drying at 80 ° C. After cooling to room temperature the film is hard and can be polished well.

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 (9)

1. Having described the invention as above, the content of the following claims is claimed as property: 1. Use of an aqueous dispersion of A) a polyol component of 20 to 60% 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, also contains 0.4 to 5% units that are derived from one or more acids unsaturated monocarboxylic or unsaturated dicarboxylic a, b, radically polymerizable by radicals with 3 to 8 carbon atoms or their anhydrides and 40 to 80% of a polyacrylate AII component) as well as B) a polyisocyanate component composed of one or various blocked aliphatic polyisocyanates, whereby component B) in parts by weight, based on the total solids dispersion content, is from 1 to 70%, for light-resistant coatings, elas tics and physically fast drying for automotive painting.
2. 2. Use of an aqueous dispersion according to claim 1, of A) a polyol component 20 to 60% of a polyester component AI) with a molecular weight of 500 to 6000, an acid number < 12 KOH / g and an OH number of 50 to 250 mg KOH / g, characterized in that AI) can be obtained by transformation of AI, 10 to 60% of one or more saturated or unsaturated aliphatic monocarboxylic acids with 8 to 30 carbon atoms AI2) 0.4 to 5% of a monocarboxylic or dicarboxylic acid a, b not saturated with 8 carbon atoms or its anhydrides AI3) 20 to 60% of one or more di-, tri-, or tetracarboxylic, aliphatic, cycloaliphatic or aromatic acids having 2 to 20 carbon atoms or their Al 4 anhydrides) 10 to 60% of one or more alcohols aliphatic with 1 to 4 OH groups per molecule AI 5) 0 to 10% of an aromatic monocarboxylic acid Al6) 0 to 10% of other compounds reactive towards acid or OH, eg. ex. : epoxides, isocyanates or oxazolinatos with 1 to 4, preferably 1.9 to 2.5 functional groups per molecule as well as 40 to 80% of a polyacrylate component AII) that can be obtained from a radical polymerization of a mixture of AII, ) 20 to 70% of one or more non-functional esters of carboxylic acids a, b not saturated with 3 to 12 carbon atoms and monoalcohols aliphatic or cycloaliphatic with 1 to 18 carbon atoms AII2) 1 to 10% of one or more carboxylic acids a, b not saturated with 3 to 12 carbon atoms or their anhydrides AII3) 0 to 95% of one or several hydroxy-functional monomers, polymerizable by radicals AII4) 0 to 20% of other radical-polymerizable monomers in the presence of the polyester component AI), whereby the data indicated in AI and AII are weight-related and total 100% thus as B) a polyisocyanate component composed of a non-hydrophilic, blocked aliphatic polyisocyanate, whereby component B) is present in parts by weight, based on the total solids content of the dispersion, in 1 to 70%. for light-fast, elastic and physically fast drying coatings for automotive painting.
3. 3. Use of an aqueous dispersion according to claim 1, characterized in that the polyisocyanate component B) is a non-hydrophilized polyisocyanate and is dispersed together with the polyol component A), for light-resistant, elastic and drying coatings. physical- Quickly for the painted series of cars.
4. 4. Use of an aqueous dispersion according to claim 1, characterized in that the polyol component A) is constituted from 40 to 55% by polyester component AI) with a molecular weight of 500 to 6000, for light-resistant coatings, elastic and physically fast drying for the painted series of cars.
5. 5. Use of an aqueous dispersion according to claim 1, characterized in that the polyol component A) is constituted from 40 to 55% by polyester component AI) with a molecular weight of 1000 to 3000 for light-resistant coatings., elastic and physically fast drying for painting in series of cars.
6. 6. Use of an aqueous dispersion according to claim 1, characterized in that the polyol component A) contains 30 to 50% of modules of one or more aliphatic monocarboxylic acids AI, with 8 to 30 carbon atoms, for resistant coatings light, elastic and physically fast drying for car series painting.
7. 7. Use of an aqueous dispersion according to claim 1, characterized in that AI "is a mixture that is composed of 80 to 100% of aliphatic monocarboxylic acids with 12 to 20 carbon atoms and less than two double bonds per molecule for resistant coatings. light, elastic and physically fast drying for painting in automobile series.
8. 8. Use 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 acid number higher than 20 mg KOH / g, for light fast, elastic and physically fast drying coatings for automotive painting.
9. 9. Use of an aqueous dispersion according to Claim 1 in combination with one or more water-dispersible melamine resins, hydrophilized polyisocyanates as well as polyester and / or polyurethane-polyester resins for light-resistant, elastic and drying coatings. Physically fast for the painted series of cars. SUMMARY OF THE INVENTION The invention relates to the use of an aqueous binder combination for the production of a physically fast-drying layer that is at the same time resistant to pebbles and stable to exposure to the elements, preferably in the series painting of automobiles.