DE4115948A1 - Coating compsn. for forming metal-pigmented base coat - for clear top coat in wet-on-wet process contains polyurethane or polyurea elastomer, polyester, and etherified aminoplast polycondensate - Google Patents

Abstract

Compsn. (I) contains metal pigments, organic solvent, conventional additives and auxiliaries, opt. other pigments, and binder (II) comprising (A) 20-60 % (all pts.wt.) one or more specified polyurethane and/or polyurea elastomers (B) 10-50% one or more specified polyesters (C) 5-25% polycondensate, partially etherified with monoalcohol, of melamine, benzoguanimine, and/or urea with HCHO, where in melamine-HCHO resins molar ratio M:F is 1:4.5-6 and in benzoguanamine or urea-HCHO resins molar ratio benzoguanamine or U:F is 1:2.5-4, (A)+(B)+(C) totalling 100%. Component (A) is prepd. from (A1) linear cpds. with terminal OH and/or prim. and/or sec. amino gps. (A2) aliphatic and/or cycloaliphatic di-isocyanates where mol.ratio (A1):(A2) = 0.8-1.5:1, while component (B) is prepd. from (B1) aromatic and aliphatic and/or cycloaliphatic polycarboxylic acids, 40-70 mol.% being aromatic, 60-30 mol.% being aliphatic and/or cyclo-aliphatic, and 0-5- mol.% total polycarboxylic acids being tricarboxylic (B2) polyols, where 20-60 mol.% polyols have 2 or 3 C and 40-80 mol.% have 4 or more C, at least 40 mol.% diols used have aliphatic side chains, 0-50 mol.% polyols are triols, and ratio (B1)/(B2) = n1-n2(F-2)/n2 = 1.05-1.5 n1 = no. mols. polyols n2 = no. mols. polycarboxylic acids F = mol. average of functionality of polycarboxylic acids. Prepn. of coatings, in which topcoat contg. metal pigment and (II) as binder is applied to form base layer followed by, after exposure to air, application in wet-on-wet process of a second coating compsn. (III) forming transparent top coat. Substrate coated with multilayer coating consisting of metal pigment-contg. base layer prepd. using a (II) and at least one transparent top layer. USE/ADVANTAGE - Prepn. of base layer in multilayer paint coating consisting of at least one base layer and at least one transparent top layer, e.g., for motor vehicle chassis. Base layers are readily printed over, even with high solids 1- or 2-component (III), show good compatibility, elasticity, and adhesion with less redissolving in wet-on-wet processes, and have good metallic effect and resistance to impact by ststs

Description

The invention relates to a coating composition for manufacture the base layer one of at least one Base layer and at least one transparent deck layer existing multi-layer coating, containing Binder based on organic resins, metal pig elements, organic solvents and, if appropriate other pigments as well as usual additives and auxiliary substances fe.

In US-PS 36 39 147 is a so-called two layer metallic paint of the above Kind described. With this and other known metallic paintwork contains the one used to make the base layer te coating compound to improve the metallic Effect of the resulting coating cellulose ester, especially cellulose acetobutyrate.

The addition of cellulose acetobutyrate brings some Disadvantages are often incompatible with other paint components, the resul tive coatings show a limited elasticity and poor interlayer adhesion and that Non-baked coatings are used in the so-called Wet-on-wet process through which to produce the transparent covering layer applied coating compound  solved.

It is an object of the present invention, this after Avoid parts of the prior art and a Coating composition for the production of the base layer of to create multi-layer metallic paintwork their use is well tolerated, good Liability and less re-dissolving occur and which without the use of cellulose acetobutyrate too Coatings with a good metallic effect.

This object is achieved by a Coating mass of the type mentioned, which thereby is characterized in that the binders from fol The following components exist:

• A) 20 to 60 wt .-% of one or more polyurethane and / or urea elastomers, made from
  • a₁) linear compounds with terminal hydroxyl and / or primary and / or secondary amino groups and
  • a₂) aliphatic and / or cycloaliphatic di isocyanates, the molar ratio a₁ to a₂ = 0.8: 1 to 1.5: 1,
• B) 10 to 50% by weight of one or more polyesters made from
  • b₁) aromatic and aliphatic and / or cyclo aliphatic polycarboxylic acids, 40 to 70 mol% of the polycarboxylic acids being aromatic and 60 to 30 mol% of aliphatic and / or cycloaliphatic polycarboxylic acids and 0 to 50 mol% of the total polycarboxylic acids being tricarboxylic acids ,
  • b₂) polyols, wherein
    • 20 to 60 mol% of the polyols have 2 or 3 carbon atoms and 40 to 80 mol% have 4 or more carbon atoms,
    • at least 40 mol% of the diols used have aliphatic side chains,
    • - 0 to 50 mol% of the polyols are triols and
    • - The ratio of components b₁ and b₂ corresponds to the following formula in which n₁ is the number of moles of polyols, n₂ is the number of moles of polycarboxylic acids and F is the mole ren average of the functionality of the polycarboxylic acids and K is 1.05 to 1.5,
• C) 5 to 25 wt .-% partially with mono alcohols etherified polycondensates from melamine, Ben pulluanamine and / or urea with formaldehyde hyd, being in the case of melamine formaldehyde Resin the molar ratio of melamine to formaldehyde hyd is 1: 4.5 to 1: 6 and in the case of benzoguanamine or urea formaldehyde Resin the molar ratio of benzoguanamine or urea to formaldehyde 1: 2.5 to Is 1: 4 and the sum of the components ten A, B and C is 100%.

Linear compounds with terminal hydroxyl groups are suitable as starting compounds a ₁ for the production of component A). So here Glycols such. B. ethylene glycol, propylene glycol, diethylene glycol or dipropylene glycol can be used. Linear polyether or polyester glycols with terminal hydroxyl groups can also be used.

The higher molecular weight polyhydroxyl compounds are said to free of aromatic urethane groups (e.g. should no prepolymers from dihydroxy compounds and below ver shot quantities of aromatic diisocyanates be applied) so that the lightfastness of the process products remains guaranteed. Polyacetals and poly ether can in principle be used because of their susceptibility to oxidative degradation less suitable. Polyesters are preferably used det, especially those made from adipic acid and diols or Mixtures of diols, e.g. B. ethylene and propylene glycol kol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, hexane diol-1,3, hexanediol-1,6 or bishydroxymethylcyclohe xan. Diols with more than four carbon atoms are preferred. Polyesters with a narrow molecule are also very suitable lar weight distribution, which by condensation of Ca prolacton and diols can be obtained.

Very excellent hydrolysis resistance, which far exceed the usual polyester properties, can be with hexanediol polycarbonates or hexane achieve diol-adipic acid mixed polycarbonates.

In addition to the higher molecular weight dihydroxyverbin mentioned dungen can possibly in the prepolymer formation small amounts (about 0.05 to 2 mol / kg elastomer) low molecular weight diols with molecular weights of approx. 62 to 400 can also be used, for example Äthy lenglycol, 1,4-butanediol, 2,3-butanediol, 2,2-dimethyl propanediol-1,3 or N-stearyl-N'N'-bis-oxyethyl urine material. Diols which are tertiary are particularly preferred  Have amino groups, for example N, N-bis- (β-hydro xyethyl) methylamine, N, N-bis (β-hydroxyethyl) isopro pylamine, N, N-bis (β-hydroxypropyl) tert.-amylamine or Bis- (3-aminopropyl) -piperazine, since it stabilizes the lity of the polyurethanes against loss of strength at Be clearing is further improved.

The starting compounds a₁ can also be linear diamines with primary and / or secondary mini groups. Examples include ethylenediamine, 1,2- or 1,3- Propylenediamine, 1,6-hexanediamine, 2-methyl-1,6-hexanedia min, 1-methyl-2,4-diamino-cyclohexane, 1-amino-3-ammo niomethyl-3,5,5-trimethylcyclohexane, 1,3- or 1,4-bis aminomethylcyclohexane, 4,4'-diaminodicyclohexylmethane or similar diamines known per se. More suitable Chain extenders are hydrazine and methyl hydrazine or adipic acid dihydrazide, semicarbazidopro pionic acid hydrazide u. Ä.

Component a 1 is with aliphatic and / or cyclo aliphatic diisocyanates to polyurethane or Urea elastomers implemented. Suitable diisocyanates are z. B. Hexamethylene-1,6-diisocyanate, 2,2,4-tri methylhexane diisocyanate, 4,8-di-oxa-6,6-dimethyl-unde can-1,11-diisocyanate, lysine-C₁-C₆-ester diisocyanates, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl 4,4'-dicyclohexylmethane diisocyanate, preferably in Form of the cis / cis or cis / trans enriched stereo isomer mixtures, 1,4-cyclohexane diisocyanate and whole especially 1-isocyanato-3-isocyanatomethyl-3,5,5- trimethylcyclohexane, since the latter gives polyurethanes, which tend to gel less in solution and the best solubility in soft-solvent mixtures to sit. The reaction can take place in the melt and / or in an inert state ten solvents, e.g. B. toluene or xylene. It is usually at temperatures between 60 ° and 150 ° C, preferably 80 ° to 120 ° C, where  the response time between about 10 minutes and more more hours.

Both pure polyurethane come as component A) elastomeric as well as pure polyurea elastomers, so such as mixtures of these elastomers or mixed poly urethane / polyurea elastomers, the urethane and Urea groupings contained in a molecule, in Consider.

The polyesters used as component B) are made from polycarboxylic acids and polyols. Appropriate polycarboxylic acids are such. B. phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, adipic acid, azelaic acid, sebacic acid or trimellitic acid. As polyols, the glycols already mentioned as components a ₁ can be used. In addition to these, glycerol, trimethylolethane, trimethylolpro pan or similar compounds are used as triols.

Amino resins are used as component C), the Po Lycondensates from melamine, benzoguanamine and / or urine are methoformaldehyde. These are partially with Mo etherified. As mono alcohols come here e.g. B. in question methanol, ethanol, propanol or butanol.

The coating compositions of the invention have a good one Compatibility of all components, good elasticity and good adhesion of the resulting coatings as well as ge ring redissolving in the wet-on-wet process. Especially when using high-solids One-component and two-component clear coats for transparent top layer they show a good coverage paintability. Furthermore, the resulting more layered coatings have a good metallic effect, even if the coating compositions according to the invention with it high solids content can be applied. Farther  it was found that the coating compositions lead to a verbes carry out stone chip protection.

The coating composition contains as further component D) advantageous to improve the metallic effect Copolymer consisting of 85 to 95 wt .-% ethylene and 15th up to 5 wt .-% vinyl acetate has been produced in egg a proportion of 5 to 30% by weight, preferably 5 to 15% by weight, based on the sum of components A) to D).

Resin A) is advantageously based on polyester diols and diamines in a molar ratio of 0.8: 1.2 to 1.2: 0.8 as component a ₁ .

The metallic effect can also be advantageous be improved that the coating mass in addition to the components A), B), C) and optionally D) as Component E) polymeric microparticles with a size or a size distribution in the range of 0.01 to 2 µm in a proportion of 5 to 50% by weight, preferably 5 to 30 % By weight, particularly preferably 5 to 15% by weight, based on the sum contains components A) to E) that have been produced by emulsion polymerization of a mixture of unsaturated Monomers, preferably part of which are carboxyl or Contains hydroxyl groups and a part free of carboxyl and Is hydroxyl groups and a polyfunctional crosslinker, wherein the emulsion polymerization was carried out in the aqueous phase and removes the water during or after the polymerization has been.

Such polymeric microparticles and the production so-called microgels are for example in the EP 00 29 637 A2 described.

The microparticles are preferred instead of the copo Limerisats from ethylene and vinyl acetate used. It but is also possible, the copolymer and the micro  Particles side by side to improve the metallic effect to use.

As unsaturated monomers for the production of the micro particles come for example acrylic acid on the one hand, Methacrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate lat, hydroxyethyl methacrylate or hydroxypropyl metha crylate and, on the other hand, alkyl esters of acrylic acid and Methacrylic acid with preferably 1 to 4 carbon atoms men in the alkyl radical as well as styrene and α-methylstyrene in Consider.

Compounds with are used as polyfunctional crosslinkers two ethylenically unsaturated double bonds net, the networked, unsolvable in the coating mass lead microparticles. Examples for this are: Ethlylene glycol dimethacrylate, tetraethylene glycol dimetha crylate, methylene bisacrylamide, methylene bis methacrylamide, Divinylbenzene, vinyl methacrylate, vinyl crotonate, vinyl acrylate, divinyl acetylene, trivinyl benzene, glycerol tri methacrylate, pentaerythritol tetramethacrylate, triallyl cyanorate, divinylethane, and similar compounds such as they are described in EP 00 29 637 A2.

The invention also relates to a method of manufacture development of coatings in which a metal pigment ent holding coating mass to form a base layer and after a flash-off time using the wet-on-wet method then a second, a transparent deck layer-forming coating composition applied to a substrate be brought. The method according to the invention is there characterized in that the binders from fol The following components exist:

• A) 20 to 60 wt .-% of one or more polyurethane and / or urea elastomers, made from
  • a₁) linear compounds with terminal hydroxyl and / or primary and / or secondary amino groups and
  • a₂) aliphatic and / or cycloaliphatic diiso cyanates, the molar ratio a₁ to a₂ = 0.8: 1 to 1.5 = 1,
• B) 10 to 50 wt .-% of one or more polyesters, forth from
  • b₁) aromatic and aliphatic and / or cyclo aliphatic polycarboxylic acids, 40 to 70 mol% of the polycarboxylic acids being aromatic and 60 to 30 mol% aliphatic and / or cycloaliphatic polycarboxylic acids and 0 to 50 mol% of the total polycarboxylic acids being tricarboxylic acids,
  • b₂) polyols, wherein
    • 20 to 60 mol% of the polyols have 2 or 3 carbon atoms and 40 to 80 mol% have 4 or more carbon atoms,
    • at least 40 mol% of the diols used have aliphatic side chains,
    • - 0 to 50 mol% of the polyols are triols and
    • - The ratio of components b₁ and b₂ corresponds to the following formula in which n₁ is the number of moles of polyols, n₂ is the number of moles of polycarboxylic acids and F is the molar mean of the functionality of the polycarboxylic acids and K is 1.05 to 1.5,
• C) 5 to 25 wt .-% ver partially with monoalcohols ethereal polycondensates from melamine, benzoguana min and / or urea with formaldehyde, where in In the case of melamine-formaldehyde resins, the molver Ratio of melamine to formaldehyde 1: 4.5 to 1: 6 and in the case of benzoguanamine or urine substance-formaldehyde resins the molar ratio benzogu anamine or urea to formaldehyde 1: 2.5 to Is 1: 4 and the sum of the components A, B and C is 100%.

Advantageous embodiments of the invention his procedure result from the subclaims chen.

Furthermore, the invention relates to one with at least one Ba containing metal pigments sis layer and at least one transparent Be existing top coat multi-layer paint layered substrate. To make the base layer is the coating composition according to the invention been used.

In the following the invention is based on Ausfü tion examples explained in more detail.  

Example A1

In a four-necked flask with stirrer, thermometer and Reflux coolers are 741 g of a polyester from Adi pinic acid and neopentyl glycol with an OH number of Weighed 113 and 26.5 g of diethylene glycol and on Heated to 100 ° C. Now vacuum is applied for half an hour to remove any moisture present. Then 1850 g of butyl are added at intervals of 5 minutes acetate, 393 g 4,4'-dicyclohexylmethane diisocyanate and 0.3 g of dibutyltin dilaurate added and the temperature is kept at 100 ° C for 1.5 h. Now the NCO Ge stop sure. It is 1.36%.

In a dilution vessel, a mixture of 1840 g butyl acetate, 1230 g n-butanol and 70 g hexa submitted methylenediamine. The containing NCO groups The preliminary product is stirred within 15-20 minutes admitted. An almost colorless viscous is obtained Solution with a solids content of 20%.

Example A2

As in Example A1, 1300 g of a caprolactone po lyesters with the OHZ number of 112 together with 73 g Neopentylglycol dewatered in a vacuum. After adding 1850 g of butyl acetate are initially 688 g of 3-isocyanato methyl-3.5.5-trimethylcyclohexyl isocyanate added. After about 5 minutes, 0.3 g of Di is added butyltin dilaurate. After a reaction time of 2 h at 100 ° C the NCO content of the solution is 2.27%.

In a dilution vessel, a mixture of 1490 g butyl acetate, 1671 g n-butanol and 88 g 1,3-di submitted aminopropane. The containing NCO groups The preliminary product is stirred within 15-20 minutes admitted. An almost colorless viscous is obtained  Solution with a solids content of 30%.

Example A3

As in Example A1, 1500 g of a polyester from hetanediol-1.6, neopentyl glycol and adipic acid dewatered in vacuo with an OH number of 75. To 2200 g of butyl acetate are first added to 393 g 4.4'-dicyclohexylmethane diisocyanate added after about 0.3 g of dibutyltin di is added over 5 minutes laurat. After a reaction time of 2 h at 100 ° C the NCO content of the solution is 0.98%.

In a dilution vessel, a mixture of 2280 g butyl acetate, 1490 g butanol and 98 g 1-amino 3-aminomethyl-cyclohexane submitted. The NCO groups containing preliminary product is stirred within added from 15-20 minutes. You get one pale yellowish viscous solution with a solid content of 25%.

Example B1

In a 2 l four-necked flask with stirrer, electric Resistance heating, thermometer, packed column ge fills with Pall rings, equipped with head thermal meter, distillation bridge, condensate cooler and pre position are weighed in 111.3 propanediol-1.3; 329.9 g 2,2-dimethylpropanediol-1,3,163.5 g 1,1,1-trimethylol propane, 216.7 g phthalic anhydride, 243.0 g Isophthalic acid, 245.0 g adipic acid, 30.0 g xylene and 2 g dibutyltin oxide. The reaction mixture is under Stir quickly heated to 160 ° C. From 160 ° C The temperature rose to 220 ° C within 5 hours tert that the column head temperature 103 ° C not exceeds. It is kept at 220 ° C and on esterified until an acid number (according to DIN) of 15 is enough. Then it is cooled to 140 ° C and the  Polyester in 800 g of a mixture of xylene and ethyl Glycol acetate dissolved in a ratio of 1: 1 rem cooling. The result is a 60% solution to one Polyester with a molecular weight of 930 and egg ner OH number (DIN) of 160, based on the fixed Po lyester.

Example B2

Using those described in Example B1 Apparatus, weigh in 60.4 g of 1,2-ethanediol, 74.0 g 1,2-propanediol, 227.9 g 2,2-dimethyl-1,3-propanediol, 229.9 g 1,6-hexanediol, 485.1 g isophthalic acid, 40.0 g of an aromatic mixture with the boiling range 180 to 205 ° C and 3.0 g of dibutyltin oxide. It will be like in Example 1 heated and esterified to one Acid number of 20. Then the mixture is cooled to 160 ° C. and 213.3 g adipic acid and 93.5 g trimellitic acid anh drid added and heated again to 200 ° C. It is kept at 200 ° C and esterified up to a Acid number of 25. It is cooled as in Example 1 and solved. The result is a 60% solution to one Polyester with a molecular weight of 960 and egg ner OH number of 115, based on the solid polyester.

Example B3

Using those described in Example B1 The apparatus and procedure are weighed in and at max. Esterified at 220 ° C.: 113.4 g of 1,2-ethanediol, 142.6 g 2,2-dimethylpropanediol-1,3,279.8 g hydroxipi valenic acid neopentyl glycol ester, 91.9 g 1,1,1-trimethy lolpropane, 303.5 g isophthalic acid, 208.5 g hexahydro phthalic anhydride, 200.2 g adipic acid, 30 g xylene, 2 g dibutyltin oxide.

It is esterified at 220 ° C up to an acid number of 5. The result is a 60% solution of a poly esters with a molecular weight of 1520 and one OH number of 100, based on the solid polyester.  

Example B4

Using the Ap. Described in Example B1 Parature and procedure are weighed in and at Max. Esterified at 220 ° C.: 102.2 g of 1,2-propanediol, 102.2 g 1,3-propanediol, 372.8 g 2,2-dimethylpropane diol-1,3, 60.0 g 1,1,1-trimethylol propane, 331.6 g Phthalic anhydride, 172.0 g trimellitic anhydride, 196.3 g of adipic acid, 40 g of an aromatic mixture with a boiling range of 180-205 ° C.

It becomes like in example 1, with special attention the head temperature, heated and esterified at 200 ° C up to an acid number of 10. As in the case of game 1 cooled and dissolved. The result is one 60% solution of a polyester with a molecular weight weight of 780 and an OH number of 198, based on the solid polyester.

Example C Melamine Resin

In a 2 l four-necked flask with an electrical counter auxiliary heating, stirrer, thermometer and distillation apparatus for circular operation with water separator are weighed in: 560 g isobutanol, 250 g 37% aqueous formaldehyde solution, 30 g toluene and 0.05 g 85% phosphoric acid. The reaction mixture is until 40 ° C heated and 95.3 g of melamine are added ben. It is heated to 85 ° C and the temperature slowly increased to 100 ° C, so that the reaction The mixture is quickly distilled, it becomes water circled. It is kept at 100 ° C until a Ben interest tolerance of 1/5 with a gasoline from Siede range of 135-180 ° C is reached. Then the Return of the distillation plant closed and 300 g Solvent distilled off; the tempera rises to 115 ° C. Then it is cooled to 80 ° C. and the reaction mixture is diluted with 65 g of isobutanol. It  results in the solution of a melamine resin with a Solids (60 min. 100 ° C) of 55% and a viscose 250 sec (DIN 53 211).

Example D copolymer dispersion

Be in a heatable mixer with high-speed stirrer weighed in: 200 g of xylene and 100 g of an ethylene vinyl acetate copolymer with a vinyl acetate content of 12% and heated to 100 ° C and until homogeneous solution touched. Then it is cooled to 80 ° C and the solution with 700 g of a mixture of xylene and butyl acetate failed, the temperature drops to 50 ° C. It results in a 10% dispersion of the copolymer.

Example E1 Preparation of a microgel concentrate

In a polymerization vessel with stirrer, reflux 2510 g of demineralizer and two feed vessels are demineralized t water together with 34 g sodium lauryl sulfate solution solution (35%) heated to 80 ° C.

In a separate stirred vessel, a Preemulsion made consisting of: 1267 g full demineralized water, 65 g sodium lauryl sulfate solution (35%), 490 g butanediol diacrylate, 478 g methyl metha crylate and 140 g hydroxypropyl methacrylate.

The initiator solution is placed in an inlet vessel, consisting of 14 g ammonium persulfate and 660 g full desalinated water. The pre-emulsion and the initiator solution are now metered simultaneously, so that the Zu run the pre-emulsion 2 h, the feed of the initiator solution Lasts 3 h. The temperature is raised to 80 ° C by cooling held. After the end of the feed, the temperature kept at 80 ° C for 1 h.  

A 20% dispersion of crosslinked is obtained Particles that do not dissolve in any organic solvent are.

2000 g of this aqueous dispersion are in one Separating funnel, together with 620 g n-butanol, 10 mi shaken intensely for a long time. After 30 minutes Waiting time you get 2 phases. The lower watery one Phase is discarded.

The microgel-containing butanol phase is combined with egg equipped with a water separator and a stirrer Still transferred to a still. For this, 333 g of the polyester described in Example B2 and 500 g Given ethyl glycol acetate. It is now in a vacuum Max. 60 ° C distilled off the remaining water azeotropically. A microgel concentrate with a solid is obtained content of 32%.

Example E2

2000 g of the aqueous dis described in Example E1 persion are in a separatory funnel together with Intensely poured 800 g of butyl acetate for 15 minutes telt. After waiting 1.5 hours, you get 2 Pha sen. The aqueous phase is discarded. The organic Phase is in a water separator and a stirrer equipped still. About who the 400 g of a polyester from adipic acid and neopen tylglycol given an OH number of 123. It will now in vacuum at max. 60 ° C everything still available Distilled water completely azeotropically. You get one Microgel concentrate with a solids content of 60%. 1500 g of this concentrate are as in Example A1 with 280 g of 4,4'-dicyclohexylmethane diisocyanate and 0.3 g Dibutyltin dilaurate added. After 2 hours of reak tion time, the NCO content is 2.66%.  

In a dilution vessel, a mixture of 1090 g Butyl acetate, 218 g n-butanol and 95 g 1-amino-3-amino submitted methylcyclohexane. The containing NCO groups Microgel-containing intermediate is stirred inside Added 15-20 minutes. You get a cloudy blue Lich shimmering pasty mass with a solid content of 40%.

Examples of basecoats 1 to 10

The polyures described in Examples A1 to A3 than / polyurea elastomer solutions with the in polyester solutions described in Examples B1 to B4 gene, the melamine formaldehyde described in Example C. hydharz and optionally with that in Example D be written copolymer dispersion and / or in the case E1 and E2 play microgel dispersion as described mixed in a stirred vessel with stirring that a homo gene mixture arises, its composition, related per 100 parts by weight of the solid substance, the information in the Table 1 corresponds. Then the one in this table specified amount of a "non-leafing" aluminum bronze paste, 65% in aliphatic hydrocarbons with 1.5 times the amount, based on the solid aluminum Umbrella on butyl acetate, carefully pasted and under Stir to the corresponding previously described Mixtures of polyurethane / polyurea elastomer sol solution, polyester, melamine-formaldehyde resin solutions and optionally copolymer dispersion or microgel ben and distributed. The resulting mixtures will be with a mixture of 50 parts by weight of butyl acetate, 25 parts by weight of butylglycol acetate and 25 parts by weight of Bu tanol adjusted to a solids content of 25% by weight.  

Table 1

Basecoats (parts by weight solids content of the solutions, based on total solids content = 100)

Example K1, clear lacquer acrylate

In a 3 l reaction vessel with thermometer, stirrer, elec trical resistance heating, reflux cooler and inlet 941 g of an aromatic mixture with a Weighed boiling range of 156-170 ° C and with stirring heated to 140 ° C. It becomes a mixture of 223 g Styrene, 223 g methyl methacrylate, 208 g 1,4-butanediol monoacrylate, 30 g acrylic acid, 803 g n-butyl acrylate and 18 g of di-tert-butyl peroxide within 3 hours evenly from the feed vessel into the reaction vessel dosed and the temperature kept at 140 ° C.

The reaction mixture is a further 30 minutes at 140 ° C. held and then a solution of 4 g of di-tert-Bu tylperoxide in 50 g of the aromatic mixture with the Siedebe rich between 156 and 172 ° C added.

After a further 2 hours at 140 ° C, an acrylic results latex resin solution with a solids content of 60%. The Acrylate resin has an acid number of 14, an OH number of 109 and a viscosity of 250 mPa · s (measured as 50% solution in xylene with the ICI viscometer).

Example K2, clear coat

To 550 g of the 60% pure described in Example K1 Acrylate resin solution be 300 g of the in Example C be written solution of the melamine-formaldehyde resin, 150 g Xylene and 50 g of butyl glycol acetate are added with stirring and mixed carefully. A clear coat results a fixed salary of 46.5%.  

Production of the covers

Sections of in the car body painting used sheets that passivate with an iron phosphating are a coating by a cathodic electro Dip coating and a stove filler received ha ben, with those described in Examples 1 to 10 Basecoats and the clear described in example K2 lacquer coated.

For this purpose, those in Examples 1 to 10 described basecoats with a solvent mixture from xylene and butyl acetate (70:30) to a viscosity of 16 sec according to DIN 53 211 and be in the example K2 wrote clear coat with this solvent mixture a viscosity of 28 sec according to DIN 53 211.

The basecoats are set with a flow mug spray gun with a nozzle width of 1.2 mm and a spray air pressure of 4 bar pre-treated body panels sprayed that a dry film thickness of the basecoats of 12 to 17 µm results. The sprayed basecoat after 5 minutes with the set clear coat, using the specified spray conditions, so ge sprayed that a dry film thickness of the clearcoat of 35 up to 40 µm results. After a flash-off time of 15 mi grooves at room temperature are the sheet metal sections in baked in a convection oven at 130 ° C for 30 minutes.

The coatings thus produced show one of one Excellent metallic judgable Effect and meet the requirements of the tech terms of delivery of automotive OEM painting listed exams.

Claims (9)

1. coating composition for the production of the base layer egg ner consisting of at least one base layer and at least one transparent top layer multi-layer coating, containing binders based on organic resins, metal pigments, organic solvents and optionally further pigments and conventional additives and auxiliaries, characterized in that that the binders consist of the following components:

• A) 20 to 60 wt .-% of one or more polyurethane and / or polyurea elastomers, made from
  • a₁) linear compounds with terminal hydroxyl and / or primary and / or secondary amino groups and
  • a₂) aliphatic and / or cycloaliphatic diiso cyanates, the molar ratio a₁ to a₂ = 0.8: 1 to 1.5: 1,
• B) 10 to 50% by weight of one or more polyesters made from
  • b₁) aromatic and aliphatic and / or cyclo aliphatic polycarboxylic acids, 40 to 70 mol% of the polycarboxylic acids being aromatic and 60 to 30 mol% of aliphatic and / or cycloaliphatic polycarboxylic acids and 0 to 50 mol% of the total polycarboxylic acids being tricarboxylic acids,
  • b₂) polyols, wherein
    • 20 to 60 mol% of the polyols have 2 or 3 carbon atoms and 40 to 80 mol% have 4 or more carbon atoms,
    • at least 40 mol% of the diols used have aliphatic side chains,
    • - 0 to 50 mol% of the polyols are triols and
    • - The ratio of components b₁ and b₂ corresponds to the following formula in which n₁ is the number of moles of polyols, n₂ is the number of moles of polycarboxylic acids and F is the mo lar average value of the functionality of the polycarboxylic acids and K is 1.05 to 1.5,
• C) 5 to 25 wt .-% partially etherified with monoalcohols polycondensates of melamine, benzoguanamine and / or urea with formaldehyde, wherein in the case of melamine formaldehyde resins, the molar ratio of melamine to formaldehyde is 1: 4.5 to 1: 6 and In the case of benzoguanamine or urea-formaldehyde resins, the molar ratio of benzoguanamine or urea to formaldehyde is 1: 2.5 to 1: 4 and the sum of components A, B and C is 100%.

2. coating composition according to claim 1, characterized net that they additionally as component D) a copo lymerisat, made from 85 to 95 wt .-% ethylene and 15 to 5% by weight vinyl acetate in one portion from 5 to 15% by weight, based on the sum of the com contains components A) to D).   3. coating composition according to claim 1 or 2, characterized in that for the preparation of the resin A) as component a ₁ ) polyester diols and diamines in a molar ratio of 0.8: 1 to 1.2: 1 have been used. 4. coating composition according to one of claims 1 to 3, because characterized in that in addition to the com components A), B), C) and optionally D) as a compo nente E) polymeric microparticles with a size or a size distribution in the range of 0.01 to 2 microns in a proportion of 5 to 15 wt .-%, based on the sum of components A) to E), which have been produced by emulsion polymers sation of a mixture of unsaturated monomers, preferably a part of which is carboxyl or Hy contains droxyl groups and a part free of Is carboxyl and hydroxyl groups and one poly functional crosslinker, the emulsion polymer Rization has been carried out in the aqueous phase and during or after the polymerization the water has been removed. 5. A process for the production of coatings, in which a coating composition containing metal pigments for forming a base layer and after a flash-off time after the wet-on-wet process, a second coating composition which forms a transparent cover layer is applied to a substrate, thereby characterized indicates that the binders of the coating composition for the base layer consist of the following components:

• A) 20 to 60 wt .-% of one or more polyurethane and / or urea elastomers, made from
  • a₁) linear compounds with terminal hydroxyl and / or primary and / or secondary amino groups and
  • a₂) aliphatic and / or cycloaliphatic di isocyanates, the molar ratio a₁ to a₂ = 0.8: 1 to 1.5: 1,
• B) 10 to 50% by weight of one or more polyesters made from
  • b₁) aromatic and aliphatic and / or cyclo aliphatic polycarboxylic acids, 40 to 70 mol% of the polycarboxylic acids being aromatic and 60 to 30 mol% of aliphatic and / or cycloaliphatic polycarboxylic acids and 0 to 50 mol% of the total polycarboxylic acids being tricarboxylic acids ,
  • b₂) polyols, wherein
    • 20 to 60 mol% of the polyols have 2 or 3 carbon atoms and 40 to 80 mol% have 4 or more carbon atoms,
    • at least 40 mol% of the diols used have aliphatic side chains,
    • - 0 to 50 mol% of the polyols are triols and
    • - The ratio of components b₁ and b₂ corresponds to the following formula in which n₁ is the number of moles of polyols, n₂ is the number of moles of polycarboxylic acids and F is the mo lar average value of the functionality of the polycarboxylic acids and K is 1.05 to 1.5,
• C) 5 to 25 wt .-% partially etherified with monoalcoholic polycondensates of melamine, benzoguanamine and / or urea with formaldehyde, the molar ratio of melamine to formaldehyde in the case of melamine-formaldehyde resins being 1: 4.5 to 1: 6 and im In the case of benzoguanamine or urea-formaldehyde resins, the molar ratio of benzoguanamine or urea to formaldehyde is 1: 2.5 to 1: 4 and the sum of components A, B and C is 100%.

6. The method according to claim 5, characterized in that the coating composition for the base layer as white tere binder component D) a copolymer, made from 85 to 95% by weight of ethylene and 15 to 5 wt .-% vinyl acetate, in a proportion of 5 to 15% by weight, based on the sum of components A) to D) contains. 7. The method according to claim 5 or 6, characterized in that for the preparation of the resin A) as component a ₁ ) polyester diols and diamines in a molar ratio of 0.8: 1 to 1.2: 1 have been used. 8. The method according to any one of claims 5 to 7, there characterized in that the coating composition additional Lich to the components A), B), C) and given if D) as component E) polymeric microparticles with a size or a size distribution in the loading range from 0.01 to 2 µm in a proportion of 5 up to 15% by weight, based on the sum of the components ducks A) to E) contains, which have been prepared are by emulsion polymerization of a mixture of unsaturated monomers, of which preferred as part of carboxyl or hydroxyl groups ent holds and a part free of carboxyl and hydroxyl groups and a polyfunctional ver netzers, the emulsion polymerization in aqueous phase has been carried out and wäh water or after polymerization has been removed. 9. With one of at least one metal pigment holding base layer and at least one trans Parent top coat existing multi-layer paint coating coated substrate, characterized net that an over use tensile mass according to one of claims 1 to 4 has been det.