DE10009412A1 - Binding agent for coating compositions for automobiles comprises binding agents dispersed in water, water soluble or dispersible polyhydroxyl compounds and blocked polyisocyanates and/or amino resins - Google Patents

Abstract

A binding agent mixture for aqueous stoved coating compositions comprises (A) binding agents dispersed in water based on polyacrylate polyols and/or polyester-polyacrylatepolyols and at least one partially blocked polyisocyanate component (B) water soluble or dispersible polyhydroxyl compounds (C) water soluble or dispersible blocked polyisocyanates and/or amino resins A binding agent mixture (I) for aqueous stoved coating compositions (II) comprises (A) binding agents dispersed in water (B) water soluble or dispersible polyhydroxyl compounds (C) water soluble or dispersible blocked polyisocyanates and/or amino resins (D) optionally other water soluble or dispersible substances whereby (A) comprises (A1) at least one polyolcomponent based on polyacrylate polyols and/or polyester-polyacrylatepolyols having a hydroxyl group content of 1.0-8.0 wt.%, a carboxyl group content of 0-3.0 wt.%, a wt. av. mol. wt of 2000-50,000 and glass transition temperature of at least 10 deg C, (A2) at least one polyisocyanate component having 5.0-25 wt.% blocked isocyanate groups based on (cyclo)aliphatic polyisocyanates (A3) optionally other polyfunctional polyols (A4) optionally other cross-linking substances (A5) optionally external emulsifiers and (A6) optionally conventional additives such that component (A) has a dispersed particle size of 0.05-10(0.1-5), preferably 0.2-1.5 mu m following preparation by a direct dispersion process or phase transfer process using a high efficiency dispersion apparatus. An Independent claim is included for aqueous stoved coating compositions (II) that contains the binding agent (I).

Description

The present invention relates to novel aqueous coating compositions for stoving coatings, in particular for the production of hard, elastic, solid bodies rich fillers for coating automobile bodies.

In recent years, the importance of water-based paints and coatings has increased due to ever stricter emission guidelines with regard to paint application released solvents strongly. Although for many people already water-based coating systems are available, they can do that high quality level of conventional, solvent-based paints with regard to solvent medium and chemical resistance or elasticity and mechanical stress Often not fully reachable. In particular, none have so far known aqueous phase to be processed coating compositions based on polyurethane, that meet the high demands in practice for hard but at the same time elastic fillers with a high solids content for coating automotive bodies with regard to Film hardness, impact strength, stone chip resistance as well as water and chemical Resistance to potassium is completely sufficient.

This statement applies to both GB-A 1 444 933, EP-A 0 061 628 and DE-A 23 59 613, which deals with the hydrophilic modification of aromatic poly deal with isocyanates, as well as for DE-A 40 01 783, which deals with special deals with anionically modified aliphatic polyisocyanates, as well as for the Systems of DE-A 24 56 469, DE-A 28 14 815, EP-A 0 012 348 and EP-A 0 424 697, which deals with aqueous stoving binders based on blocked polyisocyanates and organic polyhydroxyl compounds. The systems based on polyurethane prepolymers containing carboxyl groups with blocked isocyanate groups according to DE-A 27 08 611 or the blocked, Water-soluble urethane prepolymers according to DE-A 32 34 590 are for the ge mentioned area of use largely unusable. Significant progress on  Elasticity and resistance to solvents, water and chemicals are all included in the Systems of DE-A 42 21 924, the combinations of special, blocked, in Water-soluble or dispersible polyisocyanate mixtures and special, in Describes water-soluble or dispersible polyhydroxyl compounds aim. Further improvements in the required baking temperature or reactivity of stoving enamels can be achieved if water-thinnable or water-dispersible polyisocyanate crosslinkers with pyrazoles as Blocking agents are used, such as. B. described in WO 97/12924 and EP-A 0 802 210.

The solids content, including binders, crosslinkers, additives, pigments and fillers of these described and some are in practical use aqueous filler is generally between 47 and 50, maximum 53% by weight. In this context, however, is desirable much higher solids content in order to increase the order efficiency at Improve application significantly. Furthermore, a much higher hardness for a better grindability of the filler, while maintaining good elasticity properties should guarantee a high level of stone chip protection.

As has now surprisingly been found, it is possible to produce stoving fillers to be processed from the aqueous phase, which, in addition to the requirements previously fulfilled in practice, have a higher solids content and, after stoving, give coatings with very high hardness but at the same time very good stone chip protection properties, when used as binders from selected combinations of the type described in more detail below. The stoving enamels according to the invention consist of:

• A) special binders dispersed in water,
• B) polyhydroxyl compounds which are soluble or dispersible in water,  
• C) water-soluble or dispersible crosslinking resins and
• D) optionally other water-soluble or dispersible substances.

By using these new binder mixtures according to the invention in aqueous stoving lacquers can achieve very high solids contents. Consequently there is an increase in order efficiency and productivity. At Fülleran Applications are obtained coatings in which the hardness and thus the Sandability and the topcoat level compared to the state of the art are improved.

The invention relates to binder mixtures for aqueous stoving enamels, consisting of:

• A) special binders dispersed in water,
• B) polyhydroxyl compounds which are soluble or dispersible in water,
• C) water-soluble or dispersible crosslinking resins and
• D) optionally further water-soluble or dispersible substances,

characterized in that component I) consists of:

• A) at least one polyol component based on polyacrylate polyols and / or polyester polyarylate polyols with a hydroxyl group content of 1.0 to 8.0% by weight, a carboxyl group content of 0 to 3% by weight, a weight average molecular weight of 2,000 to 50,000 and one Glass transition temperature ≧ 10 ° C,  
• B) at least one polyisocyanate component with blocked isocyanate groups based on (cyclo) aliphatic polyisocyanates containing blocked isocyanate groups from 5.0 to 25.0% by weight,
• C) optionally further polyfunctional polyols,
• D) optionally further crosslinking substances,
• E) optionally external emulsifiers and
• F) any customary additives,

with the proviso that component I) either after a direct dispersion drive or by the phase inversion method using a dispersing device was produced with a high volume-based dispersion capacity and a medium Particle size of the dispersion particles from 0.05 to 10 microns, preferably 0.1 to 5 µm, in particular at 0.15 to 2.5 µm and particularly preferably 0.2 to 1.5 µm Has particle diameter.

The polyol component A) of the dispersion I) essential to the invention consists of

• a) 0 to 100 parts by weight of a polyester component consisting of at least a polyester polyol with a hydroxyl number of 20 to 240 mg KOH / g an acid number of <20 mg KOH / g and a glass transition temperature of -40 to + 100 ° C,
• b) 0 to 15 parts by weight of an olefinically unsaturated ester component, be consisting of at least one maleic acid di (cyclo) alkyl ester with 1 to 12 Carbon atoms in the (cyclo) alkyl radical,  
• c) 0 to 70 parts by weight (cyclo) alkyl ester of acrylic and / or methacrylic acid with 1 to 18 carbon atoms in the (cyclo) alkyl radical,
• d) 0 to 70 parts by weight of aromatic, olefinically unsaturated monomers,
• e) 5 to 60 parts by weight of hydroxyalkyl esters of acrylic and / or methacrylic acid with 2 to 4 carbon atoms in the hydroxyalkyl radical and / or their order Settlement products with a maximum molecular weight of 500 with ε-Capro lactone and addition products of acrylic and / or methacrylic acid and Monoepoxide compounds that are also used during the radical polymeri can be generated in situ,
• f) 0 to 10 parts by weight of olefinically unsaturated carboxylic acids and
• g) 0 to 30 parts by weight of further copolymerizable, olefinically unsaturated Links,

the sum of the parts by weight of components a) to g) being 100.

The polyol component A) has a hydroxyl group content of 1 to 8% by weight, preferably 1.5 to 6% by weight and particularly preferably 2 to 5% by weight. The Carboxyl group content is 0 to 3% by weight, preferably 0.1 to 1.7% by weight and particularly preferably 0.2 to 1.3% by weight. That by means of gel permeations Determinable molecular weight (weight average, standard poly styrene) is 2000 to 50,000, preferably 2500 to 40,000 and especially before moves 3000 to 35 000. The glass transition temperature according to the differential thermo analysis (DTA) is at ≧ 10 ° C, preferably at 20 to 100 ° C and especially before moves at 30 to 80 ° C.

The polyol component A) preferably consists of

• a) 0 to 60 parts by weight of a polyester component consisting of at least a polyester polyol with a hydroxyl number of 30 to 200 mg KOH / g an acid number of <15 mg KOH / g and a glass transition temperature of -30 to + 80 ° C,
• b) 0 to 12.5 parts by weight of an olefinically unsaturated ester component, be consisting of at least one maleic acid di (cyclo) alkyl ester with 1 to 6 Carbon atoms in the (cyclo) alkyl radical,
• c) 5 to 65 parts by weight (cyclo) alkyl ester of acrylic and / or methacrylic acid with 1 to 15 carbon atoms in the (cyclo) alkyl radical,
• d) 0 to 65 parts by weight of styrene, α-methylstyrene and / or vinyl toluene,
• e) 5 to 55 parts by weight of hydroxyalkyl esters of acrylic and / or methacrylic acid with 2 to 4 carbon atoms in the hydroxyalkyl radical and / or their order Settlement products with a maximum molecular weight of 500 with ε-Capro lactone and addition products of acrylic and / or methacrylic acid and Monoepoxide compounds that are also used during the radical polymeri can be generated in situ.
• f) 0 to 7.5 parts by weight of acrylic acid, methacrylic acid, maleic acid, fumaric acid and / or maleic or fumaric acid semiesters with 1 to 8 carbon atoms in the alcohol residue and
• g) 0 to 25 parts by weight of further copolymerizable, olefinically unsaturated Links,

the sum of the parts by weight of components a) to g) being 100.  

Component A) particularly preferably consists of

• a) 0 to 50 parts by weight of a polyester component consisting of at least a polyester polyol with a hydroxyl number of 40 to 160 mg KOH / g an acid number of <12 mg KOH / g and a glass transition temperature of -30 to + 70 ° C,
• b) 0 to 10 parts by weight of dimethyl maleate, diethyl maleate, Maleic acid dibutyl ester or mixtures of these monomers
• c) 5 to 60 parts by weight of (cyclo) alkyl esters of acrylic and / or methacrylic acid with 1 to 12 carbon atoms in the (cyclo) alkyl radical,
• d) 5 to 50 parts by weight of styrene,
• e) 10 to 50 parts by weight of hydroxyethyl acrylate, hydroxyethyl methacrylate, Hy hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate and / or hydroxybutyl methacrylate,
• f) 0.5 to 5 parts by weight of acrylic acid and / or methacrylic acid and
• g) 0 to 20 parts by weight of further copolymerizable, olefinically unsaturated Links,

where the sum of components a) to g) is 100.

The polyester component a) is at least one hydroxy functional polyester with a hydroxyl number of 20 to 240 mg KOH / g, preferably example, 30 to 200 mg KOH / g and particularly preferably 40 to 160 mg KOH / g. The Acid number is below 20 mg KOH / g, preferably below 15 mg KOH / g and be particularly preferably below 12 mg KOH / g. The glass transition temperature of the polyester component  a) is -40 to + 100 ° C, preferably -30 to + 80 ° C and especially preferably -30 to + 70 ° C. That from the stoichiometry of the output used The molecular weight of the polyester polyols is approximately 460 to 11300 g / mol, preferably at about 570 to 7500 g / mol and particularly preferably at approx. 700 to 5700 g / mol.

A total of 6 groups of monomer components can be used in the production of the hydroxy-functional polyesters:

• 1. (Cyclo) alkanediols (i.e., dihydric alcohols aliphatically bound with (cyclo) those hydroxyl groups) of the molecular weight range 62 to 286, such as. B. Ethanediol, 1,2- and 1,3-propanediol, 1,2-, 1,3- and 1,4-butanediol, 1,5-pentane diol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,4-dimethanol, 1,2- and 1,4-cyclohexanediol, 2-ethyl-2-butylpropanediol, containing ether oxygen Diols such as B. diethylene glycol, triethylene glycol, tetraethylene glycol, Dipropylene glycol, tripropylene glycol, polyethylene, polypropylene or poly butylene glycols with a maximum molecular weight of about 2000 preferably about 1000 and particularly preferably about 500. Reaction products the aforementioned diols with ε-caprolactone can also be used as diols for Get involved.
• 2. Trihydric and higher alcohols in the molecular weight range 92 to 254, such as B. glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol and Sorbitol.
• 3. Mono alcohols such as B. ethanol, 1- and 2-propanol, 1- and 2-butanol, 1- Hexanol, 2-ethylhexanol, cyclohexanol and benzyl alcohol.
• 4. Dicarboxylic acids in the molecular weight range 116 to approximately 600 and / or their anhydrides, such as. B. phthalic acid, phthalic anhydride, isophthalic acid, Tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid,  Hexahydrophthalic anhydride, maleic anhydride, fumaric acid, Succinic acid, succinic anhydride, adipic acid, dodecanedioic acid, hy third dimer fatty acids.
• 5. Highly functional carboxylic acids or their anhydrides such as. B. Trimellith acid and trimellitic anhydride.
• 6. Monocarboxylic acids, such as. B. benzeoic acid, cyclohexane carboxylic acid, 2-ethyl hexanoic acid, caproic acid, caprylic acid, capric acid, lauric acid, natural and synthetic fatty acids.

In the preparation of the polyester polyols a), any mixtures of the Monomer components 1) to 6) are used, with the proviso that the off choice is made so that the resulting polyesters have both OH numbers in the range of 20 to 240 mg KOH / g with acid numbers of <20 mg KOH / g as well as glass transition have temperatures from -40 to + 100 ° C.

This condition is met if a ge in the manufacture of the polyester suitable ratio of "softening" monomer components that lead to the Er lowering the glass transition temperature of the polyester lead to "hardening" Monomers that increase the glass transition temperature are used is coming.

"Softening" monomer components are, for example, aliphatic diols, such as e.g. B. 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol or aliphatic dicarbon acids, such as B. adipic acid or dodecanedioic acid.

"Hardening" monomer components are, for example, cyclic aromatic Dicarboxylic acids, such as. B. phthalic acid, isophthalic acid and terephthalic acid or Diols such as B. cyclohexanediol-1,4, cyclohexane-1,4-dimethanol or neopentyl glycol.  

The polyester a) is prepared in a manner known per se by methods, as for example in "Ullmann's Encyclopedia of Technical Chemistry", publisher Chemie Weinheim, 4th edition (1980), volume 19, pages 61 ff or H. Wagner and H. F. Sarx in "Lack-kunstharze", Carl Hanser Verlag, Munich (1971), pages 86 to 152, are described in detail. The esterification may be carried out in counter were a catalytic amount of a conventional esterification catalyst, as in for example acids such. B. p-toluenesulfonic acid, bases such as. B. Lithium hydroxide or transition metal compounds, such as. B. titanium tetrabutylate, at about 80 to 260 ° C, preferably 100 to 240 ° C.

The esterification reaction is carried out until the desired values for the hydroxyl and acid numbers are reached. The molecular weight of the polyester polyols can be derived from the stoichiometry of the starting materials (taking into account the resulting hydroxyl and acid numbers) can be calculated.

Component b) consists of at least one maleic acid di (cyclo) alkyl ester with 1 to 12, preferably 1 to 8 and particularly preferably 1 to 4 carbon atoms in the (cyclo) alkyl radical. Are suitable for. B. dimethyl maleate, malein acid diethyl ester, maleic acid di-n-butyl ester, maleic acid di-2-ethylhexyl ester, Maleic acid di-n-decyl ester, maleic acid di-n-dodecyl ester and maleic acid dicyclo hexyl ester.

Component c) consists of at least one (cyclo) alkyl ester of acrylic and / or methacrylic acid with 1 to 18, preferably 1 to 15 and especially before adds 1 to 12 carbon atoms in the (cyclo) alkyl radical, such as. B. methyl (meth) acrylate, Ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate, stearyl (meth) acrylate and benzyl (meth) acrylate.  

Component d) consists of at least one aromatic, olefinically unsound saturated monomers, such as. B. styrene, α-methylstyrene and vinyl toluene. Styrene is be prefers.

Component e) consists of at least one hydroxyalkyl ester of acrylic and / or methacrylic acid with 2 to 6 carbon atoms in the hydroxyalkyl radical and / or their reaction products with a maximum molecular weight of 500 with ε-caprolactone and addition products of acrylic and / or methacrylic acid and monoepoxide compounds that are also used during radical polymerization can be generated in situ. Can be used for. B. Hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate (when adding propylene oxide (Meth) acrylic acid resulting isomer mixture), hydroxybutyl (meth) acrylate, Um Settlement products of these monomers with ε-caprolactone up to a maximum Molecular weight of 500. The term "hydroxyalkyl ester" is therefore also intended to be an ester contain groups, such as by addition of ε-caprolactone of simple hydroxyalkyl esters. There are also implementation products of acrylic and / or methacrylic acid with monoepoxide compounds that additionally can still carry OH groups as "hydroxyalkyl esters of (meth) acrylic acid" watch and therefore also suitable as monomers e). Examples of suitable ones Monoepoxides are ®Cardura E 10 (Shell), 2-ethyl-hexylglycidylether and Glycidol (1,2-epoxy-3-propanol). These reaction products can also be found under the Radical polymerization reaction conditions are generated in situ. The simple hydroxyalkyl esters (ethyl, propyl and butyl) of acrylic and / or meth acrylic acid are preferred.

Component f) consists of at least one olefinically unsaturated carbon acid such as As acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic acid and / or fumaric acid semiesters with 1 to 18 carbon atoms in the alcohol radical. Acrylic and methacrylic acid are preferred.  

Component g) consists of copolymerizable, olefinically unsaturated compounds Bonds that differ from the connection classes of components a) to 0 are, such as α-olefins, such as. B. 1-octene or 1-decene; Vinyl esters like e.g. B. Vinyl acetate, vinyl propionate, vinyl butyrate, ®VeoVa 9 and ®VeoVa 10 from Shell; other vinyl compounds, such as e.g. B. N-vinylpyrrolidone, N-vinylcaprolactam, N- Vinyl carbazole, but also polyunsaturated compounds such as. B. Hexandioldi acrylate, trimethylolpropane triacrylate, divinylbenzene, and polybutadienes with one Molecular weight from 500 to 10,000.

The polyol component A) is prepared by radical polymerization of components b) to g) either in an inert organic solvent or solvent-free in substance, e.g. B. in the presence of component a). The component a) is conveniently presented, but can also be used as a mixture with the mono Mercury components b) to g) are used in the radical polymerization come. However, it is also possible to use component a) after the polymerization of the Mix components b) to g) into the resulting finished polymer. In the Production of the polyol component A) can be used as starting materials a) to g) within any mixtures used in the quantitative limits specified above with the proviso that this selection is made so that the resulting Polyol binder hydroxyl numbers and glass transition temperatures within the have areas mentioned above.

This condition is met when a in the preparation of the copolymers suitable ratio of "plasticizing" monomers, which are used to lower the Glass transition temperature lead to "hardening" monomers, which lead to the er increase the glass transition temperature, is used.

"Softening" monomers are, for example, alkyl esters of acrylic acid, such as e.g. B. ethyl acrylate, n-butyl acrylate, isobutyl acrylate and 2-ethylhexyl acrylate.  

"Hardening" monomers are, for example, short-chain (cyclo) alkyl esters Methacrylic acid, such as. B. methyl methacrylate, ethyl methacrylate, isopropyl methacrylic lat, isobutyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, neopentyl methacrylate, isobornyl methacrylate and 3,3,5-trimethylcyclohexyl methacrylate; Vinyl aromatics such as B. styrene, vinyl toluene and α-methylstyrene.

Suitable initiators for carrying out the radical polymerization are usual radical starters, such as. B. aliphatic azo compounds such as azo diisobutter acid nitrile, azo-bis-2-methylvaleronitrile, 1,1'-azo-bis-1-cyclohexanenitrile and Alkyl azo-bis-isobutyrate; symmetrical diacyl peroxides, such as. B. acetyl, Propionyl or butyryl peroxide, with bromine, nitro, methyl or methoxy groups substituted benzoyl peroxides, lauyl peroxides; symmetrical peroxydicarbonates, e.g. B. Diethyl, diisopropyl, dicyclohexyl and dibenzoyl peroxydicarbonate; tert-butyl peroxy-2-ethylhexanoate, tert-butyl perbenzoate; Hydroperoxides such as tert-butyl hydroperoxide, cumene hydroperoxide; Dialkyl peroxides, such as dicumyl peroxide, tert-butylcumyl peroxide, di-tert-butyl peroxide or di-tert-amyl peroxide.

Suitable solvents for the preparation of the polyol component A) are, for. B. such Solvents which after the emulsification step by vacuum distillation from the aqueous phase of a dispersion can be removed and preferably against are inert via isocyanate groups. Examples include ketones such as acetone and Methyl ethyl ketone and esters such as ethyl acetate and butyl acetate and aromatics such as Toluene and xylene.

In the preparation of the polyol binder A) is in a polymerization reactor submitted a reaction medium for the radical polymerization and on the desired polymerization temperature heated. Can be used as a polymerization medium e.g. B. serve a solvent or a mixture of the solvents specified above, if intended for use, the polyester component a) or the Component b). It is also possible to use any combination of solvent and to use components a) and / or b) as the reaction medium. after the  desired polymerization temperature is reached, the monomer mixture, be standing from the components c) to g) and optionally a) and / or b) and the Free radical initiator, preferably starting simultaneously, to the reaction medium dosed. The olefinically unsaturated constituents of the monomer mixture copolymerized by free radicals, polyester optionally used a) by grafting reactions that are more or less under the reaction conditions can take place with the copolymer is chemically combined. The polyester Component a) preferably has no unsaturated double bonds. By ever to achieve special product properties, it may also be appropriate To use polyester, which has a small proportion of polymerizable double bonds have and thus can undergo copolymerization reactions.

The polymerization temperature is 80 to 220 ° C, preferably 90 to 200 ° C and particularly preferably at 120 to 180 ° C.

Conventional regulators can be used to regulate the molecular weight of the polyol binders be used when carrying out the polymerization. Named as an example be as a regulator mercaptans, such as. B. tert-dodecyl mercaptan, n-dodecyl mercaptan and mercaptoethanol.

In general, the polymerization takes place, in particular when Solvents of the type specified above, in a closed pressure polymer station reactor with automatic temperature control at a pressure of up to 20 bar. With a solvent-free driving style and the use of high-boiling mono The polymerization can also be carried out under atmospheric pressure be performed.

The polyol binders obtained by the polymerization process described A) make valuable binder components for the production of the Invention represent aqueous powder suspensions and form the essential polyol stock part, optionally in addition to other hydroxyl-containing components  C), which in minor proportions if necessary in addition to the polyol component A) can be placed.

Component B) is blocked polyisocyanates, preferably um (cyclo) aliphatic biuret, isocyanurate, urethane, uretdione, allophanate, and / or polyisocyanates containing iminooxadiazinedione groups. It can too Polyisocyanates are used, the several of these groups contain. The known (cyclo) alipha can be used to prepare the polyisocyanates table diisocyanates are used, from which the polyisocyanates by be known methods such. B. trimerization, allophanatization, urethanization, Biuretization can be made. 1,6-Diiso are preferably used cyanatohexane (HDI), 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (Isophorone diisocyanate, IPDI), 2,4- and / or 2,6-diisocyanato-1-methylcyclohexane and 4,4'-diisocyanatodicyclo-hexylmethane (®Desmodur W, Bayer AG). Especially Isocyanurate, biuret and / or are preferred for the production of component B) Polyisocyanates containing urethane groups based on 1.6 diisocyanatohexane, Isophorone diisocyanate and ®Desmodur W used.

To produce the polyisocyanate component B), the poly Isocyanates with conventional blocking agents in a blockage known per se blocking reaction and optionally modified hydrophilically.

The known monofunctional blocking agents are used as blocking agents used such. B. dimethyl malonate, diethyl malonate, acetoacetic acid acid ethyl ester, ε-caprolactam, butanone oxime, cyclohexanone oxime, 1,2,4-triazole, Dimethyl-1,2,4-triazole, 3,5-dimethylpyrazole, imidazole, di-n-propylamine, diisopro pylamine, di-n-butylamine, diisobutylamine or dicyclohexylamine. Preferably turned on are blocking agents that are in the temperature range up to 180 ° C, particularly preferably split off up to 160 ° C. Butanone oxime, cyclohexanone oxime, 3,5- Dimethylpyrazole and 1,2,4-triazole.  

If the polyisocyanate component B) is modified hydrophilically, this happens according to known methods, d. H. in which a part of the isocyanate groups with Hy droxycarboxylic acids, e.g. B. 2,2-dimethylolpropionic acid or 3-hydroxy-2,2-dimethyl propanoic acid (hydroxypivalic acid) and / or with monofunctional polyethers a content of ethylene oxide of at least 70 wt .-% is implemented. At Modification with hydroxycarboxylic acids is for the solution or dispersion in Water which requires at least partial neutralization with an amine to generate ionic groups.

To prepare the crosslinking component B), the polyisocyanate is used in succession in any order or simultaneously with the blocking agent and / or the Hydroxycarboxylic acid and / or the polyether implemented. Preferably the Polyisocyanates are not hydrophilized but only blocked. It can be a small excess as well as a small deficit of blocking agent for Get involved. If there is a deficit of blocking agents, it can also continue are working when small amounts of unreacted isocyanate groups in the Reaction mixture are present. The implementation is usually done in one Temperature range from 10 to 120 ° C, preferably at 20 to 120 ° C, wherein be especially the reactions with hydroxycarboxylic acids under mild conditions be carried out to prevent that the carboxyl group with the Iso cyanate groups reacted.

The reactions can be carried out solvent-free or in an inert solvent leads. The reaction in inert solvents is preferred, preference being given to as the aforementioned solvents are used, especially ethyl acetate, butyl acetate, acetone and methyl ethyl ketone, toluene and xylene.

When the reaction has ended, if there is hydrophilization with a carboxylic acid has taken place, possibly at least partially a neutralization of the built carboxyl groups with a neutralizing agent. Suitable neutralis Sationsmittel are alkali or alkaline earth metal hydroxides, but preferably ammonia and  Amines such as B. triethylamine, triethanolamine, N-methylmorpholine, and especially preferably N, N-dimethylethanolamine. In general, if necessary present carboxyl groups neutralized at least 50%, where appropriate an excess of neutralizing agent can also be used.

The other polyols C) which may be used are are substances with at least one hydroxyl group, such as. B. the Her position of the polyester polyols already described low molecular weight alcohols, furthermore polyether alcohols with 1 to 6 hydroxyl end groups, polyurethane polyols with at least one hydroxyl end group, further polyester and / or polyacrylate polyols or ε-caprolactone polyester with at least one hydroxyl end group.

In the case of the additional crosslinker component that may be used D) are substances which, like the crosslinking substances B) chemical reaction with the hydroxyl groups of component A) and given if C) lead to a hardening of the coatings according to the invention. Exemplary mention should be made of aminoplast resins, e.g. B. corresponding melamine derivatives, such as alkoxy gelled melamine resins or melamine-formaldehyde condensation products (e.g. FR-A 943 411, "The Chemistry of Organic Filmformers", pages 235-240, John Wiley & Sons Inc., New York 1974) and conventional crosslinking agents, e.g. B. with alcoholic Hydroxyl-reactive epoxides, carboxylic acid anhydrides, phenolic resins, Resole resins, urea resins or guanidine resins or mixtures thereof.

In the case of the external emulsifiers E) which may be used are common emulsifiers or dispersants, such as those by Johann Bielmann in Lackadditive, WILEY-VCH Verlag GmbH Weinheim, New York, Chichester, Brisbane, Singapore, Toronto 1998, pages 87-92 are described. Plant, for example, are particularly suitable as substances E) tion products of ethylene oxide and optionally propylene oxide to hydrophobic Starter molecules, such as. B. nonylphenol, phenol / styrene condensates and long-chain, optionally branched alcohols, such as lauryl alcohol or stearyl alcohol. But  also ionic compounds of this type, such as ethylene oxide and optionally sulfuric or phosphoric acid containing propylene oxide units ester salts such as e.g. B. described in WO 97/31960, are as substances E) suitable.

The usual additives F) that may be used are involved it is, for example, neutralizing agents, catalysts, auxiliaries and / or Additives such as B. degassing agents, leveling agents, radical scavengers, antioxidants and / or UV absorbers, thickeners, small amounts of solvents and biocides.

The polyhydroxyl component II) is, for example, in water soluble or dispersible polyhydroxyl compounds by gel permeation Chromatography (standard polystyrene) determinable number-average Molecular weight of 1000 to 100,000, preferably 2000 to 20,000, of the known from the chemistry of polyurethane coatings, provided the Polyhy Droxyl compounds have a solubility or dispersibility in Water sufficient content of hydrophilic groups, in particular Polyether chains containing carboxylate groups and / or ethylene oxide units. In principle, however, the use of on its own is not possible sufficient hydrophilic polyhydroxyl compounds mixed with external ones Emulsifiers.

Possible component II) are polyhydroxy polyesters and polyhydroxy poly ethers, polyhydroxypolyurethanes, polyhydroxycarbonates, urethane-modified poly ester polyols, urethane modified polyether polyols, urethane modified polycarbo polymers containing nat polyols or hydroxyl groups, d. H. which in itself be knew polyhydroxy polyacrylates. However, mixtures of these can also be used called polyhydroxy compounds, or in situ, optionally ge grafted, representatives of combinations of these polyhydroxyl compounds, such as. B. Polyester polyacrylate polyols, polyether polyacrylate polyols, polyurethane polyacrylate polyols, polyester polyurethanes, polyether polyurethanes, polycarbonate polyurethanes  and polyether polyester or mixtures thereof as component II) are used come.

The polyacrylate polyols are known copolymers of simple esters of acrylic and / or methacrylic acid, the introduction of Hydroxyl groups hydroxyalkyl esters such as 2-hydroxyethyl, the 2-Hy droxypropyl, 2-, 3-, or 4-hydroxybutyl esters of these acids can also be used and the introduction of carboxyl groups, which are to be converted into carboxylate groups can be neutralized with amines, acrylic and / or Methacrylic acid used. Other possible comonomers are ole finically unsaturated compounds, such as. B. vinyl aromatics, acrylonitrile, Maleic acid di (cyclo) alkyl esters, vinyl esters, vinyl ethers and the like. s. w ..

The polymers can on the one hand directly in water with the aid of Emul gators are produced, whereby emulsion copolymers are formed, which also "Primary dispersions" are called. On the other hand, the production is in orga African solvents and, after the introduction of ionic groups, subsequent over guiding into the aqueous phase possible, so-called "secondary dispersions" be preserved.

Suitable polyether polyols are those known per se from polyurethane chemistry Ethoxylation and / or propoxylation products of suitable 2- to 6-valent Starter molecules such as B. water, ethylene glycol, propanediol, trimethylolpropane, Glycerin, pentaerythritol and / or sorbitol.

Examples of suitable polyester polyols are in particular those in polyurethane Chemically known reaction products of polyhydric alcohols example of alkane polyols of the type just mentioned with below shot amounts of polycarboxylic acids or polycarboxylic anhydrides, esp special dicarboxylic acids or dicarboxylic acid anhydrides. Suitable polycarbonate Acids or polycarboxylic anhydrides are, for example, adipic acid, phthalic acid,  Isophthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydro phthalic anhydride, maleic acid, maleic anhydride, the Diels-Alder-Ad Products with cyclopentadiene, fumaric acid or dimeric or trimeric fatty acids. Around to set special molecular weights or functionalities of the polyester polyols, be there is also the possibility of using monofunctional alcohols, such as e.g. B. 2-ethylhexanol or cyclohexanol and / or monofunctional carboxylic acids, such as B. 2-ethylhexanoic acid, benzoic acid or cyclohexane carboxylic acid. At the Her position of the polyester polyols can of course be any mixtures of mono- and polyfunctional alcohols or any mixtures of mono- and polyfunctional carboxylic acids or carboxylic anhydrides are used.

The polyester polyols are prepared by known methods, such as, for. B. in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 2, G. Thieme- Verlag, Stuttgart, 1963, pages 1 to 47 are described.

The hydrophilic modification of these polyester polyols which may be required is carried out according to methods known per se, such as, for example, in EP-A 0 157 291 or EP-A 0 427 028. The described in these publications level, water-soluble or dispersible, urethane-modified polyesters particularly suitable according to the invention as component II). Particularly preferred as Component II) come into consideration urethane-modified polyester resins, as in DE-A 42 21 924 are described. Also suitable, but less preferred, are those described in DE-A 38 29 587, water-soluble or dispersible hydroxyl-containing polyacrylates.

The polyfunctional crosslinking resins III) are either water-soluble or dispersible blocked polyisocyanates as well as water-soluble or dispersible bare amino resins, such as. B. melamine resins. In principle, they are suitable water-soluble or dispersible polyisocyanates, as they have been before were mentioned in the prior art. However, those in water are particularly suitable  soluble or dispersible blocked polyisocyanates described in DE-A 42 21 924 and DE-A 198 10 660 are described.

It is also possible to use already finished mixtures of representatives of components II) and III) as a combination partner for component I) essential to the invention use. Such finished mixtures are due to their good stock stability at room temperature already in practice.

For example, epoxy can be used as further water-dispersible substances IV) resins, phenolic resins, polyamine resins, low molecular weight epoxy crosslinkers and low molecular polyamine crosslinkers are used.

For the preparation of the dispersions I) essential to the invention by dispersing processes arrive at dispersing devices with high volume-related dispersing performance, such as B. pressure relief homogenizing nozzles for use.

Corresponding dispersing machines are e.g. B. from Formation of Emulsions, in P. Beche, Encyclopedia of Emulsion Technology, Vol. 1, New York, Basel, Decker 1983; known. but were used for the production of such aqueous dispersions aqueous burn-in fillers have not yet been used.

Dispersing machines are designed according to the size of the volume-related output chooses. For the production of finely divided dispersions (approx. 1 µm particle diameter knives) dispersing machines with high volume-related outputs are required derlich, z. B. high pressure homogenizers. So with rotor / stator machines no longer produce finely divided dispersions. In the case of EP-A 0 101 007 described jet disperser is a special Druckent voltage nozzle, which has a much higher efficiency than high pressure has homogenizers. Even with 50 bar homogenization pressure with the jet dispersant particle size distributions achieved for the high pressure homogenizer 200 bar required.  

The jet disperser as a dispersing device can be particularly advantageous Produce finely divided dispersions, both continuously and discontinuously.

According to the invention, the aqueous dispersion can also be reversed from one phase Water-in-oil can be converted into an oil-in-water emulsion.

The inventive aqueous dispersions essential to the invention 1) can be used in combination with components II), III) and optionally IV) Stove enamel can be used on any heat-resistant substrates, e.g. B. as a filler, basecoat or topcoat for the production of single-layer and / or Multicoat paint systems, for example in the automotive sector. The before drawn use is in the filler area.

To produce the coating compositions I) according to the invention Components A), B) and optionally C) to F) written together mixes, preferably in the solvents already mentioned. Preferred as a solvent are ethyl acetate and methyl ethyl ketone, methyl ethyl ketone is particularly preferred. Of course, components A) and B) can also be obtained directly in solution be put and then these solutions are mixed. Especially before components A) and B) are produced in methyl ethyl ketone and then mixed.

In this solution of A) and B) can, if necessary and not before ge, if necessary, further polyfunctional crosslinking substances, neutralizing agents, small amounts of external emulsifiers and other auxiliaries and additives, such as. B. thickeners, leveling agents, light stabilizers and / or catalysts. The organic solution is then mixed with water to produce the aqueous suspensions. This is done either by the direct dispersion process, in which the organic phase is dispersed in the aqueous phase, or by the phase reversal process, in which an initially present water-in-oil emulsion is converted into an oil-in-water emulsion. This is done with the aid of a dispersing device with a high volume-based dispersing capacity. It can be z. B. are cage stirrer, dissolver, rotor / stator mixer, pressure relief nozzles, preferably jet dispersers, the volume-based dispersing power for the dispersing process at 1 to 10 ⁸ W / cm ³ , preferably 1 to 5.10 ⁷ W / cm ³ and particularly preferably 1 to 3.10 ⁷ W / cm ³ . The average particle size of the particles of the aqueous dispersions or suspensions is 0.05 to 10 μm, preferably 0.1 to 5 μm, in particular 0.15 to 2.5 μm and particularly preferably 0.2 to 1.5 μm.

In order to obtain special particle size distributions, it makes sense or is advantageous to disperse in several stages with defined volume-related performance.

It has proven to be advantageous before the jet dispersing process dispersant to prepare a pre-emulsion using a stirrer or dissolver and then feed this pre-emulsion to the jet disperser. In the preparation of the dispersions or emulsions such an amount of water is used that 20 to 75% by weight, preferably 30 to 70% by weight and particularly preferred 35 to 70% by weight dispersions or emulsions of those essential to the invention Binder I) result. After the addition of water, the solvent preferably removed by vacuum distillation.

The dispersion can be in a wide temperature range at both lower Temperature, such as B. 10 ° C, as well as at a higher temperature to well above the Melting point of the polymer mixture, such as. B. 150 ° C take place. At such high Temperatures are only a short one due to the reactivity of the binder systems timely temperature exposure in the seconds range possible.

In principle, however, a procedure for producing the aqueous dispersions or suspensions, which consists of free carboxyl and Mixtures of A) containing hydroxyl groups and blocked isocyanate groups  and B), optionally in the form of an organic solution in one of the examples mentioned solvents, with an aqueous solution of a neutralizing agent to mix mentioned type, so that neutralization and dissolving or dispersing take place in one stage.

The mixing ratio of the polyhydroxy component A) to the blocked poly Isocyanate component B) is chosen so that the equivalent ratio of blocked isocyanate groups of component B) to alcoholic hydroxyl Groups of component A) at 0.5: 1 to 2: 1, preferably at 0.6: 1 to 1.8: 1 and is particularly preferably 0.7: 1 to 1.5: 1.

Further polyfunctional hydroxyl compounds C), polyfunctional crosslinking agents D), External emulsifiers E) and customary additives F) can be added to the aqueous binder mixed medium but also the individual components A) and B) before the union or already in the production or the mixture of A) and B) before the dispersing be added. In the case of water soluble or dispersible Substances C) to F) can also be added after the dispersion and distillation of the aqueous phase can be added.

For the production of ready-to-use coating agents, especially fillers, the special dispersions I) essential to the invention with the polyhydroxyl compounds II), the crosslinkers III) and, if appropriate, representatives of the component IV) mixed. The mixing ratio with respect to components I) to III) is in the range from 90: 5: 5 to 10: 45: 45% by weight, preferably 85: 7.5: 7.5 to 15: 42.5: 42.5% by weight and particularly preferably 80: 10: 10 to 20: 40: 40% by weight moved to solid. Representatives of component IV) can optionally in An divide up to 20 wt .-%, preferably 10 wt .-%, based on solid, for Ein sentence come. Only mixtures of components I) to are particularly preferred III) used. The one-component binders thus obtained are generally Can be stored for any length of time. If necessary, auxiliary materials and additives coating technology, such as pigments, fillers, leveling agents,  Wetting and dispersing agents, anti-bubble agents, catalysts and the can resemble the aqueous binder or binder mixture and / or the Individual components I), II), III) and optionally IV) are added. From be It is a particular advantage that the individual components I), II), III) and optionally IV) or I) and the mixture of II) and III) with auxiliaries, pigments and fillers to process ready-to-use pastes, which can then be used within the above ge mentioned limits can be mixed together. This way achieve very special properties for special requirements. It also exists the possibility of adding some additives, e.g. B. leveling agents or catalysts, the Add component I) before it is dispersed in water.

The one-component Be containing the dispersions I) essential to the invention Layering agents can be applied by any coating method technology such as B. spraying, brushing, dipping, flooding or with the help of rollers and doctor blades, applied to any heat-resistant substrates with one or more layers will wear.

For example, coatings on metal, plastic, wood or glass are obtained Curing the paint film at 80 to 220 ° C, preferably 100 to 200 ° C and be particularly preferably 120 to 180 ° C.

The binders according to the invention are preferably suitable for the production of Coatings and paints on steel sheets, such as those used for manufacturing position of vehicle bodies, machines, cladding, barrels or con tainers are used. They are preferably used for the production of Automotive fillers. The paint films generally have a dry layer thickness from 0.01 to 0.3 mm.

The binders according to the invention result in long-lasting surfaces protection, as demonstrated in the examples. Especially the surprisingly high one Impact resistance combined with high film hardness, which are opposing properties  are to be emphasized. This makes the binders for applications which require good stone chip protection paired with a high paint film hardness is ideally suited.

The special advantage of the new aqueous binders is their high stability Lity when stored both at room temperature and at slightly elevated Temperatures of 30 to 60 ° C the particularly high solids content of ≧ 55 wt .-% under application conditions, which of previously known aqueous Binder is usually not achieved.

The following examples illustrate the invention, but without it restrict.  

Examples

Unless otherwise stated, all percentages relate to the weight.

1. Production of Dispersions I) Essential to the Invention Polyol component A) General working instructions for the production of a polyester-polyacrylate polyol, or polyacrylate polyols

In a 10 l stainless steel pressure reactor with stirring, cooling and heating device as well Electronic temperature control is presented in Part I under a nitrogen atmosphere and heated to reaction temperature. Then in the closed reactor beginning at the same time part II (addition over a period of 3 Hours) and Part III (addition over a period of 3.5 hours in total) constant temperature of the reactor contents metered. After adding Part III, 1 Stirred hour at the polymerization temperature. Then the resulting one Cooled resin solution to 30 ° C and filtered.

The reaction temperatures and the compositions of parts I to III are in Table 1 listed together with the characteristics of the products obtained.

Source material polyester

Polyester polyol with a hydroxyl number of 98 mg KOH / g and an acid number of 1.5 mg KOH / g, prepared by reacting 22.07 parts by weight of 2-ethylhexanoic acid, 30.29 parts by weight of trimethylolpropane, 12.67 parts by weight of neopentyl glycol, 32.24 parts by weight of hexahydrophthalic anhydride and 12.29 parts by weight of adipine acid.  

Table 1

Polyols A) of the binders I) essential to the invention (quantities in g)

Preparation of crosslinker component B) Polyisocyanate 1

In a 2 l four-necked flask with stirrer, gas inlet tube, internal thermometer, Dropping funnel and reflux condenser, 1332 g of isophorone diisocyanate (IPDI) under Nitrogen submitted and heated to 80 ° C. A dropping funnel becomes inside 15 ml of a 5% by weight solution of 2-hydroxypropyltri within 45 minutes methylammonium hydroxide in 2-ethyl-1,3-hexanediol / methanol (6: 1, parts by weight) added slowly and evenly. The temperature rises to 88 ° C (90 ° C should not be exceeded because the trimerization is too high Temperatures are non-specific and lead to higher viscosities of the end product leads). After the dropping has ended, the mixture is stirred at 80 ° C. until the Reaction mixture has reached an NCO content of 30.6%. Then you stop by adding 0.36 g (70 ppm molar) of a 25% solution of dibutyl phosphate in IPDI. Excess monomeric IPDI is removed by thin film distillation removed. An almost colorless, clear resin is obtained with a yield of 44%, which is 70% dissolved in methyl ethyl ketone. The viscosity of the solution at 23 ° C is 300 mPa.s, the isocyanate content is 11.8% and the content of free, monomeric IPDI is 0.18%.

Polyisocyanate 2

®Desmodur N 3300 (Bayer AG), fixed content: 100%; Viscosity at 23 ° C: 3500 mPa.s; Isocyanate content: 21.8%.

Polyisocyanate 3

In a 2 l four-necked flask with stirrer, gas inlet tube, internal thermometer and Reflux condenser, 524.00 g of 4,4'-diisocyanatodicyclohexylmethane (®Desmodur W, Bayer AG) and 146.24 g of 2,2,4-trimethyl-1,3-pentanediol under nitrogen  submitted and heated to 100 ° C. With stirring, 1 ml of dibutyltin dilaurate added so slowly (exothermic reaction) that a temperature of 120 ° C does not is exceeded. After the dropping has ended, the batch will remain as long as 100 ° C stirred until the reaction mixture reaches an NCO content of 12.5% Has. An almost colorless, clear resin is obtained which, after cooling to 75 ° C. 445.83 g of methyl ethyl ketone is dissolved. The expiry time of the 60% solution is 23 s (ISO 4 cup, 23 ° C) and the isocyanate content is 7.5%.

Preparation of a blocked polyisocyanate B 1

500 g of polyisocyanate 1 are in a 1 liter four-necked flask with a stirrer, internal thermo Meter and reflux condenser submitted and heated to 60 ° C. 134.86 g of 3,5-dimethyl pyrazole are added in portions with stirring and then at 60 ° C for as long stirred until no isocyanate band can be seen in the IR spectrum.

Preparation of a blocked polyisocyanate B 2

500 g of polyisocyanate 1 are in a 1 liter four-necked flask with a stirrer, internal thermo meter, reflux condenser and dropping funnel and heated to 60 ° C. Then 122.22 g of butanone oxime are added dropwise with stirring within 30 minutes. The mixture is stirred at 60 ° C until no more isocyanate band in the IR spectrum you can see.

Preparation of a blocked polyisocyanate B 3

500 g of polyisocyanate 1 are in a 1 liter four-necked flask with a stirrer, internal thermo Meter and reflux condenser submitted and heated to 60 ° C. 158.74 g cyclo Hexanone oxime are added in portions with stirring and then for as long 60 ° C stirred until no isocyanate band can be seen in the IR spectrum.  

Preparation of a blocked polyisocyanate B 4

350 g of polyisocyanate 2 are in a 1 liter four-necked flask with a stirrer, internal thermo meter and reflux condenser with 150 g of methyl ethyl ketone and stirring Heated to 50 ° C. Then 205.28 g of cyclohexanone oxime are added in portions and stirred at 50 ° C until no more isocyanate band in the IR spectrum see is.

Preparation of a blocked polyisocyanate B 5

385.40 g of polyisocyanate 2 are in a 1 l four-necked flask with stirrer, inside submitted thermometer and reflux condenser and heated to 60 ° C. 192.26 g 3.5- Dimethylpyrazole are added in portions with stirring and then for as long stirred at 60 ° C until no more isocyanate band can be seen in the IR spectrum.

Preparation of a blocked polyisocyanate B 6

385.40 g of polyisocyanate 2 are in a 1 l four-necked flask with stirrer, inside submitted thermometer and reflux condenser and heated to 60 ° C. 138.14 g 1,2,4- Triazole are added in portions with stirring and then at 60 ° C for as long stirred until no isocyanate band can be seen in the IR spectrum.

Preparation of a blocked polyisocyanate B 7

560.00 g of polyisocyanate 3 are in a 1 liter four-necked flask with a stirrer, internal therm mometer and reflux condenser and heated to 60 ° C. 96.13 g 3,5-Di Methylpyrazole are added in portions with stirring and then for as long 60 ° C stirred until no isocyanate band can be seen in the IR spectrum.  

Preparation of a blocked polyisocyanate B 8

560.00 g of polyisocyanate 3 are in a 1 liter four-necked flask with a stirrer, internal therm mometer and reflux condenser and heated to 60 ° C. 69.07 g of 1,2,4-triazole are added in portions with stirring and then stirred at 60 ° C. until no isocyanate band can be seen in the IR spectrum.

Preparation of the Aqueous Dispersions I) Essential to the Invention Dispersion I.1)

397.2 g of the polyester polyacrylate polyol A 1 and 190.4 g of the blocked polyiso cyanates B 1 are dissolved in 456 g of methyl ethyl ketone (MEK) and with 3 g of the Neu Tralisationsmittel added dimethylethanolamine. Then 12.6 g Emulsifier WN (emulsifier, Bayer AG) added and by stirring a homogeneous mixture of the components is produced.

A water-in-oil emulsion is prepared from 963 g of the solution of polyol, polyisocyanate, neutralizing agent and additive in MEK by intensive mixing with 500 g of water using a dissolver, which is then passed through a jet disperser at elevated pressure (60 bar). according to EP 0101007 experiences a phase reversal in an oil-in-water emulsion. The MEK is distilled off in vacuo. Then stabilized with 6 g of emulsifier WN. Then it is filtered through a filter with a mesh size of 10 µm. The result is a polymer dispersion with the following characteristics:
Flow time (ISO 4 cup, 23 ° C): 13 sec
Solids content: 44.3% by weight
average particle size (laser correlation spectroscopy): 0.22 µm
Glass transition temperature: 61 ° C

Dispersion I.2)

303.6 g of polyacrylate polyol A 2 and 222.0 g of blocked polyisocyanate B 2 are dissolved in 440.5 g MEK and with 2.7 g of the neutralizing agent dimethyl ethanolamine added. Then 11.4 g of emulsifier NP 30 (emulsifying aid medium, from Bayer AG) and a homogeneous mixture of Components manufactured.

A water-in-oil emulsion is prepared from 825 g of the solution of polyol, polyisocyanate, neutralizing agent and additive in MEK by intensive mixing with 500 g of water using a dissolver, which is then passed through a jet disperser at elevated pressure (1.0 bar) according to EP 0101007 experiences a phase reversal in an oil-in-water emulsion. The MEK is distilled off in vacuo. Then it is filtered through a filter with a mesh size of 10 µm. The result is a polymer dispersion with the following characteristics:
Flow time (ISO 4 cup, 23 ° C): 9 sec
Solids content: 34.0% by weight
average particle size (laser correlation spectroscopy): 0.37 µm
Glass transition temperature: 53 ° C

Dispersion I.3)

303.5 g of polyacrylate polyol A 2, 157.8 g of blocked polyisocyanate B 3 and 64.9 g of the blocked polyisocyanate B 4 are dissolved in 446.2 g of MEK and with 2.7 g of the neutralizing agent dimethylethanolamine were added. Then be 11.5 g of emulsifier NP 30 are added and, by stirring, a homogeneous mixture of Components manufactured.  

From 954 g of the solution of polyol, polyisocyanate, neutralizing agent and additive in MEK, a water-in-oil emulsion is produced by intensive mixing with 500 g of water using a dissolver, which is then passed through a jet disperser at elevated pressure (1.0 bar) according to EP 0101007 experiences a phase reversal in an oil-in-water emulsion. The MEK is distilled off in vacuo. Then it is filtered through a filter with a mesh size of 10 µm. The result is a polymer dispersion with the following characteristics:
Flow time (ISO 4 cup, 23 ° C): 15 sec
Solids content: 47.0% by weight
average particle size (laser correlation spectroscopy): 0.35 µm
Glass transition temperature: 47 ° C

Dispersion I.4)

305.0 g of polyacrylate polyol A 2, 77.7 g of blocked polyisocyanate B 3 and 131.1 g of the blocked polyisocyanate B 4 are dissolved in 204.4 g MEK and with 2.7 g of the neutralizing agent dimethylethanolamine were added. Then be 11.3 g of emulsifier NP 30, dissolved in 50 g of MEK, are added and one is stirred homogeneous mixture of components.

A water-in-oil emulsion is prepared from 770 g of the solution of polyol, polyisocyanate, neutralizing agent and additive in MEK by intensive mixing with 400 g of water using a dissolver, which is then passed through a jet disperser at elevated pressure (1.0 bar) according to EP 0101007 experiences a phase reversal in an oil-in-water emulsion. The MEK is distilled off in vacuo. Then it is filtered through a filter with a mesh size of 10 µm. The result is a polymer dispersion with the following characteristics:
Flow time (ISO 4 cup, 23 ° C): 20 sec
Solids content: 56.0% by weight
average particle size (laser correlation spectroscopy): 0.35 µm
Glass transition temperature: 38 ° C

Dispersion I.5)

308.5 g of polyacrylate polyol A 3 and 222.0 g of blocked polyisocyanate B 2 are dissolved in 441.5 g MEK and with 2.7 g of the neutralizing agent dimethyl ethanolamine added. Then 11.4 g of emulsifier NP 30 are added and a homogeneous mixture of the components is produced by stirring.

From 957 g of the solution of polyol, polyisocyanate, neutralizing agent and additive in MEK, a water-in-oil emulsion is produced by intensive mixing with 500 g of water using a dissolver, which is then passed through a jet disperser at elevated pressure (1.0 bar) according to EP 0101007 experiences a phase reversal in an oil-in-water emulsion. The MEK is distilled off in vacuo. Then it is filtered through a filter with a mesh size of 10 µm. The result is a polymer dispersion with the following characteristics:
Flow time (ISO 4 cup, 23 ° C): 14 sec
Solids content: 43.1% by weight
average particle size (laser correlation spectroscopy): 0.42 µm
Glass transition temperature: 52 ° C

Dispersion I.6)

364.58 g of polyacrylate polyol A 2, 36.11 g of blocked polyisocyanate B 5 and 328.12 g of the blocked polyisocyanate B 7 are dissolved in 529.40 g of MEK and with 3.35 g of the neutralizing agent dimethylethanolamine were added. Subsequently 16.78 g of emulsifier WN (emulsifier, Bayer AG) and 7.55 g Synperonic PE / F 127 (emulsifying aid, ICI Surfactants) added and by Stirring a homogeneous mixture of the components.  

A water-in-oil emulsion is produced from 1008.26 g of the solution of polyol, polyisocyanate, neutralizing agent and additives in MEK by intensive mixing with 500.00 g of water using a dissolver, which is then passed through a jet disperser at elevated pressure (1.0 bar) according to EP 0101007 undergoes a phase reversal in an oil-in-water emulsion. The MEK is distilled off in vacuo. Then it is filtered through a filter with a mesh size of 10 µm. The result is a polymer dispersion with the following characteristics:
Flow time (ISO 4 cup, 23 ° C): 12 sec
Solids content: 50.0% by weight
average particle size (laser correlation spectroscopy): 0.32 µm
Glass transition temperature: 32.5 ° C

Dispersion I.7)

364.58 g of polyacrylate polyol A 2, 32.73 g of blocked polyisocyanate B 6 and 314.37 g of the blocked polyisocyanate B 8 are dissolved in 504.12 g MEK and with 3.35 g of the neutralizing agent dimethylethanolamine were added. Subsequently 16.20 g of emulsifier WN (emulsifying aid, Bayer AG) and 7.30 g Synperonic PE / F 127 added and by stirring a homogeneous mixture of Components manufactured.

A water-in-oil emulsion is prepared from 1008.46 g of the solution of polyol, polyisocyanate, neutralizing agent and additives in MEK by intensive mixing with 500.00 g of water using a dissolver, which is then passed through a jet disperser at elevated pressure (10 bar) according to EP 0101007 undergoes a phase reversal in an oil-in-water emulsion. The MEK is distilled off in vacuo. Then it is filtered through a filter with a mesh size of 10 µm. The result is a polymer dispersion with the following characteristics:
Flow time (ISO 4 cup, 23 ° C): 13 sec
Solids content: 50.0% by weight
average particle size (laser correlation spectroscopy): 0.25 µm
Glass transition temperature: 43.5 ° C

2. Examples of use

The production of stoving fillers using base pastes is described as they are usually used in practice.

• 1. Base paste based on a self-crosslinking polyurethane dispersion (®Bayhydrol VP LS 2153, Bayer AG), consisting of a water-dispersed polyhydroxy compound and a water-dispersed blocked polyisocyanate (not according to the invention).
  For a grinding of 30 minutes in a bead mill, the following components are weighed out and predispersed for about 10 minutes using a dissolver: 670.9 parts by weight of the 40% self-crosslinking polyurethane dispersion Bayhydrol VP LS 2153; 6.5 parts by weight of dimethylethanolamine, 10% in dist. Water; 6.0 parts by weight of a commercially available anti-cratering agent; 6.0 parts by weight of a commercially available wetting agent; 4.0 parts by weight of an anti-settling agent used in the paint industry; 118.5 parts by weight of titanium dioxide; 1.3 parts by weight of iron oxide black; 119.2 parts by weight of micronized heavy spar; 29.1 parts by weight of carbonate-free talc and 38.5 parts by weight of distilled water. This results in a paste with a solids content (binder: pigment / fillers = 1: 1) of approx. 53.6% by weight.
• 2. Base paste based on the self-crosslinking dispersion I.5 essential to the invention
  The following components are weighed out, predispersed for about 10 minutes using a dissolver and then ground in a bead mill for 30 minutes: 692.5 parts by weight of the 43.1% self-crosslinking dispersion I.5); 3.0 parts by weight of a commercially available defoamer; 4.5 parts by weight of an anti-settling agent used in the paint industry; 132.5 parts by weight of titanium dioxide; 1.4 parts by weight of black iron oxide; 133.5 parts by weight of micronized heavy spar and 32.6 parts by weight of carbonate-free talc. This results in a paste with a solids content (binder: pigment / fillers = 1: 1) of approx. 59.7% by weight.
• 3. Base paste based on the self-crosslinking dispersion I.4) essential to the invention
  The following components are weighed out, predispersed for about 10 minutes using a dissolver and then rubbed in a bead mill for 30 minutes: 680.4 parts by weight of a 45.6% self-crosslinking dispersion I.4); 3.1 parts by weight of a commercially available defoamer; 4.6 parts by weight of an anti-settling agent used in the paint industry; 137.7 parts by weight of titanium dioxide; 1.5 parts by weight of iron oxide black; 138.8 parts by weight of micronized heavy spar and 33.9 parts by weight of carbonate-free talc. This results in a paste with a solids content (binder: pigment / fillers = 1: 1) of approx. 62.4% by weight.

Production of aqueous fillers based on base pastes 1 to 3.

The pastes are made according to the ratios given in the table below homogeneously mixed by dispersing for 10 minutes using a dissolver and ge if necessary with water to a processing viscosity of ≦ 35 s (ISO Cup 5 mm, ISO 2431) set. The compositions and characteristics of the obtained aqueous filler is shown in Table 2 below.  

Table 2

Composition of aqueous filler

The solid contents of the fillers 4 and 5 according to the invention are significantly higher and their Viscosity stability after 40 ° C storage better than with the high-quality comparison filler 1. The fillers 2 and 3 not according to the invention based on the pastes of the components I) essential to the invention have the highest fixed contents of all Examples, the other filler properties are not sufficient, as in is shown below.

The aqueous fillers 1 to 5 were with a commercially available flow cup gun 5 bar air pressure at approx. 65% rel. Humidity (23 ° C) with a cathodic abge various electrodeposition primers (approx. 20 µm) coated zinc phosphated Spray-applied steel sheets.  

The fillers hardened after 10 minutes flashing at 23 ° C in Convection oven first at 70 ° C for 10 min and then at 165 ° C for 20 min. The Dry film thickness was approx. 35 µm.

The properties of the fillers are listed in Table 3 below

Table 3

Properties of the filler

The fillers 4 and 5 according to the invention have compared to the commercially available Filler 1 has a very high hardness and a very good elasticity for this hardness. The shine filler values are at a similar level. The fillers 2 and 3 have a bit higher hardness than fillers 4 and 5 according to the invention, but worse Elasticity and less gloss.

A commercially available automotive topcoat was applied to the filler layers Alkyd / melamine resin using an air atomizing spray gun with a dryer film thickness of approx. 30 µm applied and cured at 130 ° C for 30 min.

The most important test results that are decisive for the filler application are in the following table summarized. Resistance values not specified, such as e.g. B. solvent, water and salt spray resistance, fully meet the requirements practical requirements.  

Test methods used Top coat stand

 Measurement of the ripple using a wave scan measuring device by Byk

Stone chip resistance

 Were used as test devices

• a) Stone chip testing device according to VDA (Erichsen, model 508) with 2 times each 500 g steel shot (angular, 4-5 mm) bombarded with an air pressure of 1.5 bar at 23 ° C. Sampling was carried out with regard to hit the sheet (0 to 10.0 = no penetration, 10 = very many Carbon copies).
• b) Single impact tester ESP-10 according to BMW standard DBP No. 34.31.390 (Fa. Byk), the flaking of the filler from the sheet is measured in mm.

Table 4

Top coat level, measurement using wave scan (Byk), (corrected values given)

The lower the numerical values for both short and long ripple the better the topcoat is. The fillers 4 to 5 according to the invention therefore lead to a better topcoat level than the comparative fillers 1 to 3.  

Table 5

Stone chip test

The fillers 4 to 5 according to the invention are at the same high level as the high one quality comparative filler 1, although the filler according to the invention a clear have higher hardness. This result is surprising and unpredictable. Fillers 2 and 3 have poorer stone chip resistance.

Summary and discussion of the results

The fillers 4 and 5 according to the invention are characterized by a very high solid body content and a very high hardness. So there was little elasticity associated with poor stone chip resistance as well as poor Topcoat level to be expected. However, the test results clearly show that he filler according to the invention, contrary to the prior art, both good Elasticity values as well as very good stone chip resistance and top coat levels exhibit and thus superior to a high quality, commercially available polyurethane filler are. You have an unprecedented level of quality in terms of the whole Property spectrum.

Claims (10)

1. Binder mixture for aqueous stoving enamels consisting of:

• A) special binders dispersed in water,
• B) polyhydroxyl compounds which are soluble or dispersible in water,
• C) water-soluble or dispersible, blocked polyisocyanates and / or amino resins and
• D) optionally further water-soluble or dispersible substances,

characterized in that component I) consists of:

• A) at least one polyol component based on polyacrylate polyols and / or polyester polyacrylate polyols with a hydroxyl group content of 1.0 to 8.0 wt .-%, a carboxyl group content of 0 to 3.0 wt .-%, a weight average molecular weight of 2000 to 50,000 and a glass transition temperature of ≧ 10 ° C,
• B) at least one polyisocyanate component with blocked isocyanate groups based on (cyclo) aliphatic polyisocyanates with a blocked isocyanate group content of from 5.0 to 25.0% by weight,
• C) optionally further polyfunctional polyols,
• D) optionally further crosslinking substances,
• E) optionally external emulsifiers and
• F) any customary additives,

with the proviso that component I) was produced either by a direct dispersing process or by the phase reversal process using a dispersing device with a high volume-based dispersing power and then an average particle size of the dispersion particles of 0.05 to 10 μm, preferably 0.1 to 5 μm in particular at 0.15 to 2.5 µm and particularly preferably 0.2 to 1.5 µm particle diameter. 2. Binder mixture according to claim 1, characterized in that the polyol component A) of component I) consists of:

• a) 0 to 100 parts by weight of a polyester component consisting of at least one polyester polyol with a hydroxyl number of 20 to 240 mg KOH / g with an acid number of <20 mg KOH / g and a glass transition temperature of -40 to + 100 ° C,
• b) 0 to 15 parts by weight of an olefinically unsaturated ester component, consisting of at least one maleic acid di (cyclo) alkyl ester with 1 to 12 carbon atoms in the (cyclo) alkyl radical,
• c) 0 to 70 parts by weight of (cyclo) alkyl esters of acrylic and / or methacrylic acid with 1 to 18 carbon atoms in the (cyclo) alkyl radical,
• d) 0 to 70 parts by weight of aromatic, olefinically unsaturated monomers,
• e) 5 to 60 parts by weight of hydroxyalkyl esters of acrylic and / or methacrylic acid with 2 to 4 carbon atoms in the hydroxyalkyl radical and / or their reaction products of a maximum molecular weight of 500 with ε-caprolactone and addition products of acrylic and / or methacrylic acid and Monoepoxide compounds that can also be generated in situ during the radical polymerization,
• f) 0 to 10 parts by weight of olefinically unsaturated carboxylic acids and
• g) 0 to 30 parts by weight of further copolymerizable, olefinically unsaturated compounds,

the sum of the parts by weight of components a) to g) being 100. 3. Binder mixture according to claim 1 and 2, characterized in that the polyol component A) of component I) consists of:

• a) 0 to 60 parts by weight of a polyester component consisting of at least one polyester polyol with a hydroxyl number of 30 to 200 mg KOH / g with an acid number of <15 mg KOH / g and a glass transition temperature of -30 to + 80 ° C,
• b) 0 to 12.5 parts by weight of an olefinically unsaturated ester component consisting of at least one maleic acid di (cyclo) alkyl ester having 1 to 6 carbon atoms in the (cyclo) alkyl radical,
• c) 5 to 65 parts by weight of (cyclo) alkyl esters of acrylic and / or methacrylic acid with 1 to 15 carbon atoms in the (cyclo) alkyl radical,
• d) 0 to 65 parts by weight of styrene, α-methylstyrene and / or vinyl toluene,
• e) 5 to 55 parts by weight of hydroxyalkyl esters of acrylic and / or methacrylic acid with 2 to 4 carbon atoms in the hydroxyalkyl radical and / or their reaction products of a maximum molecular weight of 500 with ε-caprolactone and addition products of acrylic and / or methacrylic acid and Monoepoxide compounds that can also be generated in situ during radical polymerization.
• f) 0 to 7.5 parts by weight of acrylic acid, methacrylic acid, maleic acid, fumaric acid and / or maleic or fumaric acid semiesters with 1 to 8 carbon atoms in the alcohol residue and
• g) 0 to 25 parts by weight of further copolymerizable, olefinically unsaturated compounds,

the sum of the parts by weight of components a) to g) being 100. 4. Binder mixture according to claims 1 to 3, characterized in that the polyol component A) of component I) consists of:

• a) 0 to 50 parts by weight of a polyester component consisting of at least one polyester polyol with a hydroxyl number of 40 to 160 mg KOH / g with an acid number of <12 mg KOH / g and a glass transition temperature of -30 to + 70 ° C,
• b) 0 to 10 parts by weight of maleic acid dimethyl ester, maleic acid diethyl ester, maleic acid dibutyl ester or mixtures of these monomers
• c) 5 to 60 parts by weight of (cyclo) alkyl esters of acrylic and / or methacrylic acid with 1 to 12 carbon atoms in the (cyclo) alkyl radical,
• d) 5 to 50 parts by weight of styrene,
• e) 10 to 50 parts by weight of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate and / or hydroxybutyl methacrylate,
• f) 0.5 to 5 parts by weight of acrylic acid and / or methacrylic acid and
• g) 0 to 20 parts by weight of further copolymerizable, olefinically unsaturated compounds,

where the sum of components a) to g) is 100. 5. Binder mixture according to claim 1, characterized in that the Component II) consists of: polyhydroxy polyesters, polyhydroxy polyethers, Polyhydroxypolyurethanes, polyhydroxycarbonates, urethane modified Polyester polyols, urethane modified polyether polyols, urethane modified graced polycarbonate polyols, hydroxyl-containing polymers, Polyester polyacrylate polyols, polyether polyacrylate polyols, polyurethane polyacrylate polyols polyester polyurethanes, polyether polyurethanes, poly carbonate polyurethanes, polyether polyesters or mixtures thereof. 6. Binder mixture according to claim 1, characterized in that the Component III) consists of: water-soluble or dispersible blocked polyisocyanates. 7. Binder mixture according to claim 1, characterized in that the Component III) consists of: water-soluble or dispersible Amino resins.   8. Use of the binder mixtures according to claims 1 to 7 for the manufacture provision of, if necessary, the usual auxiliaries and additives of the Be aqueous stoving lacquers containing layering technology. 9. Aqueous stoving varnish, the binder of which consists of a combination

• A) special binders dispersed in water,
• B) polyhydroxyl compounds which are soluble or dispersible in water,
• C) water-soluble or dispersible, blocked polyisocyanates and / or amino resins and
• D) optionally further water-soluble or dispersible substances,

consists, characterized in that component I) consists essentially of

• A) a polyol component based on polyacrylate polyols, polyester polyacrylate polyols with a hydroxyl group content of 1.0 to 8.0 wt .-%, a carboxyl group content of 0 to 3.0 wt .-%, a weight average molecular weight of 2000 to 50,000 and one Glass transition temperature of ≧ 10 ° C,
• B) a polyisocyanate component with blocked isocyanate groups based on (cyclo) aliphatic polyisocyanates with a blocked isocyanate group content of from 5.0 to 25.0% by weight,
• C) optionally further polyfunctional polyols,
• D) optionally further crosslinking substances,
• E) optionally external emulsifiers and
• F) if appropriate, conventional additives.

and that component I) was produced either by a direct dispersion process or by the phase inversion process using a dispersing device with a high volume-based dispersing power and then has an average particle size of the dispersion particles of 0.05 to 10 μm. 10. Use of the aqueous stoving lacquer according to claim 9 for Her Provision of fillers for automotive body parts.