DURABLE 2K PUR COATINGS

Description

[0001] The invention relates to novel coating compositions containing polyester polyols based on 2,2,4,4-tetraalkylcyclobutane-1,3-diols and crosslinking components containing isocyanate groups and simultaneously silane groups, and to the use of these coating compositions for producing coatings, in particular clearcoats for automotive painting, and to the coated substrates.

[0002] Since their introduction into automotive OEM coatings in the mid-1980s, two-component polyurethane (2K-PUR) clearcoats have steadily gained market share due to their superior technological properties compared to traditional acrylate / melamine resin coating systems (thermosetting acrylics, TSA coatings).

[0003] Today's 2K PUR clear coats, which generally contain hydroxy-functional poly(meth)acrylate resins as binders and aliphatic polyisocyanates, particularly derivatives of hexamethylene diisocyanate (HDI), as crosslinking components, provide coatings with high mechanical and chemical resistance and very good appearance.

[0004] Despite the high quality level already achieved with 2K PUR coatings, there is a constant interest in the market for coating systems with ever-improving properties, in particular improved chemical resistance, such as against solvents and tree resin, and scratch resistance.

[0005] WO 2010 / 090712, WO 2010 / 090714, WO 2010 / 090715, and WO 2016 / 187095 propose the use of aliphatic polyesters based on 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) as a binder component for solvent-borne coating systems with improved solvent and chemical resistance. When blended with polyacrylate polyols, such polyester polyols also reduce the viscosity of the overall system, thus enabling the formulation of lower-solvent coatings. At the same time, however, the high glass transition temperature of the TMCD polyesters significantly impairs scratch resistance.

[0006] DE 101 03 027 A1 discloses the use of solvent-based two-component polyurethane binders containing a hardener component consisting of an addition product of a polyisocyanate with an alkoxysilane and a coating resin reactive toward isocyanate groups as adhesion promoters. This is applied to a substrate before an inorganic or organic coating or an inorganic-organic hybrid coating can be applied.

[0007] As has now surprisingly been discovered, 2K-PUR coatings in which polyester polyols based on TACD are combined with special polyisocyanates containing silane groups show a significantly improved scratch resistance compared to analogous coatings crosslinked with silane-free polyisocyanates, while maintaining the same high chemical resistance.

[0008] The present invention relates to coating compositions containing A) at least one polyol component, B) at least one crosslinker component having free and / or blocked isocyanate groups obtained by reacting at least one polyisocyanate with at least one amino-functional alkoxysilane, optionally C) at least one catalyst for crosslinking silane groups and D) optionally further auxiliaries and additives, characterized in that the polyol component A) comprises at least one polyester polyol A1) which is prepared using a 2,2,4,4-tetraalkylcyclobutane-1,3-diol (TACD) of the general formula (I) was prepared in which the radicals R 1< , R 2< , R 3< and R 4< independently of one another represent linear or branched alkyl radicals with up to 8 carbon atoms.

[0009] The invention also relates to the use of these coating compositions for the production of polyurethane coatings, in particular for the production of clear coats for automotive painting.

[0010] According to the invention, references to "comprising," "containing," etc., preferably mean "consisting essentially of" and most preferably "consisting of." The further embodiments mentioned in the claims and in the description can be combined as desired, unless the context clearly indicates otherwise.

[0011] The coating compositions according to the invention contain a polyol component A) which comprises at least one polyester polyol A1) which is obtained using a 2,2,4,4-tetraalkylcyclobutane-1,3-diol (TACD) of the general formula (I) was prepared in which the radicals R 1< , R 2< , R 3< and R 4< independently of one another represent linear or branched alkyl radicals having up to 8 carbon atoms, preferably having up to 6 carbon atoms, particularly preferably up to 4 carbon atoms and most preferably a methyl radical.

[0012] Such polyester polyols A1) are known. They are prepared in a conventional manner, for example by the processes described in WO 2010 / 090712, WO 2010 / 090714, WO 2010 / 090715, and WO 2016 / 187095, by reacting TACD of the general formula (I), optionally with the concomitant use of other polyhydric alcohols, with substoichiometric amounts of polybasic carboxylic acids, corresponding carboxylic anhydrides, or corresponding polycarboxylic acid esters of lower alcohols.

[0013] Suitable TACDs for the preparation of the polyester polyols A1) used according to the invention are, for example, 2,2,4,4-tetramethylcyclobutane-1,3-diol (TMCD), 2,2,4,4-tetraethylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-propylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-butylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-pentylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-hexylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-heptylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-octylcyclobutane-1,3-diol, 2,2-Dimethyl-4,4-diethylcyclobutane-1,3-diol, 2-ethyl-2,4,4-trimethylcyclobutane-1,3-diol, 2,4-dimethyl-2,4-diethylcyclobutane-1,3-diol, 2,4-dimethyl-2,4-di-n-propylcyclobutane-1,3-diol, 2,4-n-dibutyl-2,4-diethylcyclobutane-1,3-diol, 2,4-dimethyl-2,4-diisobutylcyclobutane-1,3-diol and 2,4-diethyl-2,4-diisoamylcyclobutane-1,3-diol. A particularly preferred cyclobutanediol is 2,2,4,4-tetramethylcyclobutane-1,3-diol (TMCD).

[0014] Other polyhydric alcohols which can optionally be used in the preparation of the polyester polyols A1) are, for example, simple polyhydric alcohols having 2 to 14, preferably 4 to 10 carbon atoms, such as: B. 1,2-ethanediol, 1,2- and 1,3-propanediol, the isomeric butanediols, pentanediols, hexanediols, heptanediols and octanediols, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,10-decanediol, 1,12-dodecanediol, 1,2- and 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-bis(2-hydroxyethoxy)benzene, 2,2-bis-(4-hydroxyphenyl)propane (bisphenol A), 2,2-bis-(4-hydroxycyclohexyl)propane (perhydrobisphenol), 1,2,3-propanetriol, 1,2,4-butanetriol, 1,1,1-Trimethylolethane, 1,2,6-hexanetriol, 1,1,1-trimethylolpropane (TMP), bis-(2-hydroxyethyl)-hydroquinone, 1,2,4- and 1,3,5-trihydroxycyclohexane, 1,3,5-tris(2-hydroxyethyl)-isocyanurate, 3(4),8(9)-bis-(hydroxymethyl)-tricyclo-[5.2.1.02,6]decane, di-trimethylolpropane, 2,2-bis(hydroxymethyl)-1,3-propanediol (pentaerythritol), 2,2,6,6-tetrakis(hydroxymethyl)-4-oxa-heptane-1,7-diol (dipentaerythritol), mannitol or sorbitol, low molecular weight ether alcohols such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol or dibutylene glycol or low molecular weight ester alcohols such as neopentyl glycol hydroxypivalate, or mixtures of at least two such alcohols.

[0015] In the preparation of the polyester polyols A1), the TACDs of the type mentioned can be used as the sole diol component. However, other polyhydric alcohols of the type mentioned may also be used if desired, with the amounts of these other polyhydric alcohols being chosen such that the TACD content of the total amount of TACD and other polyhydric alcohols used is at least 10 mol%, preferably at least 35 mol%, more preferably at least 50 mol%, and most preferably at least 70 mol%.

[0016] Suitable carboxylic acids or carboxylic acid derivatives for preparing the polyester polyols A1) to be used in the coating compositions according to the invention are polybasic carboxylic acids, their carboxylic anhydrides, and polycarboxylic acid esters of lower alcohols. These are any aromatic, aliphatic, or cycloaliphatic, saturated or unsaturated di- and tricarboxylic acids or their anhydrides, in particular those having 4 to 18 carbon atoms, preferably having 4 to 10 carbon atoms, such as, for example,Succinic acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, tetrahydrophthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, trimellitic acid, tetrahydrophthalic anhydride, terephthalic acid dimethyl ester and terephthalic acid bis-glycol ester but also dimeric and trimeric fatty acids, which can be used individually or in the form of any mixtures with each other.

[0017] Preferred carboxylic acids or carboxylic acid derivatives for the preparation of the polyester polyols A1) are isophthalic acid and adipic acid.

[0018] If necessary, monocarboxylic acids such as benzoic acid, acetic acid, propionic acid, butyric acid or 2-ethylhexanoic acid can also be used in minor amounts to produce the polyester polyols A1).

[0019] Suitable polyester polyols A1) for the coating compositions according to the invention also include those which can be prepared in a conventional manner from lactones and TACD and optionally other polyhydric alcohols, such as those exemplified above, as starter molecules by ring opening. Suitable lactones for preparing these polyester polyols A1) are, for example, β-propiolactone, γ-butyrolactone, γ- and β-valerolactone, ε-caprolactone, 3,5,5- and 3,3,5-trimethylcaprolactone, or any mixtures of such lactones.

[0020] The preparation of these lactone polyesters is generally carried out in the presence of catalysts such as Lewis or Brönstedt acids, organic tin or titanium compounds at temperatures of 20 to 200°C, preferably 50 to 160°C.

[0021] Irrespective of the preparation process and the type of synthesis components used, the polyester polyols A1) obtained using TACD and used in the coating compositions according to the invention generally have a hydroxyl group content of 1.5 to 15% by weight, preferably 2 to 10% by weight, particularly preferably 2.4 to 8% by weight, very particularly preferably 2.8 to 6% by weight, acid numbers of 0 to 80 mg KOH / g, preferably from 0 to 25 mg KOH / g, particularly preferably from 2 to 15 mg KOH / g, very particularly preferably 2 to 10 of 0 to 25 mg KOH / g and number-average molecular weights (Mn) of 300 to 10,000 g / mol, preferably from 500 to 6,000 g / mol, particularly preferably from 800 to 5,000 g / mol.

[0022] The glass transition temperature Tg of the polyester polyols A1) is generally from -35 to 100°C, preferably from -35 to 60°C, particularly preferably from -35 to 50°C.

[0023] Suitable polyester polyols A1) for the coating compositions according to the invention are, for example, the polyesters based on 2,2,4,4-tetramethylcyclobutane-1,3-diol (TMCD) commercially available under the trade name Eastman Tetrashield™< from Eastman Chemical Company, Kingsport, USA.

[0024] In addition to the TACD-based polyester polyols A1), the polyol component A) of the coating compositions according to the invention optionally comprises further polyols A2) different from A1).

[0025] Suitable polyols A2) are, for example, the usual polyhydroxyl compounds known from polyurethane chemistry, such as TACD-free polyester polyols, polyether polyols, polycarbonate polyols and / or polyacrylate polyols, or any mixtures of such polyols.

[0026] Suitable TACD-free polyester polyols A2) are, for example, those having an average molecular weight, calculable from functionality and hydroxyl number, of 200 to 3000, preferably 250 to 2500, with a hydroxyl group content of 1 to 21% by weight, preferably 2 to 18% by weight, as can be prepared in a manner known per se by reacting polyhydric alcohols with substoichiometric amounts of polybasic carboxylic acids, corresponding carboxylic anhydrides, corresponding polycarboxylic acid esters of lower alcohols or lactones.

[0027] Suitable building blocks for the production of these polyester polyols A2) are - with the exception of the TACD - for example the polyhydric alcohols, polybasic carboxylic acids and their derivatives mentioned above as suitable for the production of the polyester polyols A1), which can also be used in the form of any desired mixtures.

[0028] The production of polyester polyols A2) can be carried out by methods known per se, as described, for example, in E. Gubbels et al., Polyesters. In: Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH Verlag GmbH & Co. KGaA; 2018. URL:https: / / doi.org / 10.1002 / 14356007.a21_227.pub2. Catalytic amounts of conventional esterification catalysts, such as acids, bases, or transition metal compounds such as titanium tetrabutylate, can be used if necessary. The esterification reaction is generally carried out in a temperature range of approximately 80 to 260°C, preferably 100 to 230°C, until the desired values ​​for the hydroxyl and acid number are reached.

[0029] Suitable polyether polyols A2) are, for example, those with an average molecular weight, calculated from functionality and hydroxyl number, of 200 to 6000, preferably 250 to 4000, and a hydroxyl group content of 0.6 to 34 wt. %, preferably 1 to 27 wt. %, as are obtainable in a conventional manner by alkoxylation of suitable starter molecules. To prepare these polyether polyols, any polyhydric alcohols, including TACD, as described above as suitable for the preparation of the polyester polyols A1), can be used as starter molecules.

[0030] Alkylene oxides suitable for the alkoxylation reaction are, in particular, ethylene oxide and propylene oxide, which can be used in any order or in a mixture in the alkoxylation reaction.

[0031] Suitable polycarbonate polyols A2) are, in particular, the known reaction products of dihydric alcohols, for example those exemplified above in the list of polyhydric alcohols, with diaryl carbonates, such as, for example, diphenyl carbonate, dimethyl carbonate, or phosgene. Suitable polycarbonate polyols A2) are also those which, in addition to carbonate structures, also contain ester groups. These are, in particular, the known polyester carbonate diols, such as those that can be obtained, for example, according to the teaching of DE-AS 1 770 245 by reacting dihydric alcohols with lactones, such as, in particular, ε-caprolactone, and subsequently reacting the resulting polyester diols with diphenyl or dimethyl carbonate. Likewise suitable polycarbonate polyols A2) are those which, in addition to carbonate structures, also contain ether groups.These are in particular the polyether carbonate polyols known per se, such as those obtainable, for example, by the process of EP-A 2 046 861 by catalytic conversion of alkylene oxides (epoxides) and carbon dioxide in the presence of H-functional starter substances.

[0032] Suitable polyacrylate polyols A2) are, for example, those having an average molecular weight of 800 to 50,000, preferably 1,000 to 20,000, which can be calculated from functionality and hydroxyl number or determined by gel permeation chromatography (GPC), and having a hydroxyl group content of 0.1 to 12% by weight, preferably 1 to 10, as can be prepared in a manner known per se by copolymerizing olefinically unsaturated monomers containing hydroxyl groups with hydroxyl-free olefinic monomers.

[0033] Examples of suitable monomers for producing the polyacrylate polyols A2) are vinyl or vinylidene monomers such as styrene, α-methylstyrene, o- or p-chlorostyrene, o-, m- or p-methylstyrene, p-tert-butylstyrene, acrylic acid, acrylonitrile, methacrylonitrile, acrylic and methacrylic acid esters of alcohols with up to 18 carbon atoms, such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, 3,3,5-trimethylhexyl acrylate, stearyl acrylate, lauryl acrylate, cyclopentyl acrylate, cyclohexyl acrylate, 4-tert.-Butycyclohexyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, 3,3,5-trimethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, norbornyl methacrylate or isobornyl methacrylate, diesters of fumaric acid, itaconic acid or maleic acid with alcohols having 4 to 8 carbon atoms, acrylamide, methacrylamide, vinyl esters of alkanemonocarboxylic acids having 2 to 5 carbon atoms, such as. B. vinyl acetate or vinyl propionate, hydroxyalkyl esters of acrylic acid or methacrylic acid with 2 to 5 carbon atoms in the hydroxyalkyl radical, such as2-Hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 3-hydroxybutyl, 4-hydroxybutyl, trimethylolpropane mono- or pentaerythritol monoacrylate or methacrylate, as well as any mixtures of such monomers mentioned as examples.

[0034] Preferred polyol components A2), which may optionally be present in the coating compositions according to the invention in addition to the polyester polyols A1), are TADC-free polyester polyols, polycarbonate polyols and / or polyacrylate polyols of the type mentioned. Particularly preferred polyol components A2) are polyacrylate polyols of the type mentioned.

[0035] In the polyol component A) of the coating compositions according to the invention, the TACD-based polyester polyols A1) and the TACD-free polyol components A2) are present in amounts such that the proportion of the polyester polyols A1) in the total polyol component A) is at least 10 wt.%, preferably at least 30 wt.%, particularly preferably at least 60 wt.%, very particularly preferably at least 80 wt.%.

[0036] The coating compositions according to the invention contain as crosslinking component B) at least one reaction product containing free and / or blocked isocyanate groups of at least one polyisocyanate with at least one amino-functional alkoxysilane.

[0037] Suitable polyisocyanates for preparing the crosslinker component B) are, for example, any diisocyanates and / or polyisocyanates with aliphatically and / or cycloaliphatically bound isocyanate groups, which are accessible in various ways, for example by phosgenation in the liquid or gas phase or by a phosgene-free route, such as by thermal urethane cleavage. Preferred aliphatic and / or cycloaliphatic diisocyanates are those in the molecular weight range 140 to 400, such as 1,4-diisocyanatobutane, 1,5-diisocyanatopentane (pentamethylene diisocyanate, PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,3- and 1,4-bis-(isocyanatomethyl)-cyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 4,4'-diisocyanatodicyclohexylmethane, 1-isocyanato-1-methyl-4(3)isocyanatomethylcyclohexane, bis-(isocyanatomethyl)-norbornane or mixtures of at least two such diisocyanates.

[0038] Suitable polyisocyanates for preparing the crosslinking component B) are also any polyisocyanates having a uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure prepared by modifying simple aliphatic and / or cycloaliphatic diisocyanates, for example those of the type mentioned above, as described, for example, in J. Prakt. Chem. 336 (1994) 185-200, in DE-A 1 670 666, DE-A 1 954 093, DE-A 2 414 413, DE-A 2 452 532, DE-A 2 641 380, DE-A 3 700 209, DE-A 3 900 053 and DE-A 3 928 503 or in EP-A 0 336 205, EP-A 0 339 396 and EP-A 0 798 299, or mixtures of at least two such polyisocyanates. In the preparation of these polyisocyanates, the actual modification reaction is generally followed by a further process step to remove the unreacted excess monomeric diisocyanates.This monomer separation is carried out according to methods known per se, preferably by thin-film distillation under high vacuum or by extraction with suitable solvents inert to isocyanate groups, for example aliphatic or cycloaliphatic hydrocarbons such as pentane, hexane, heptane, cyclopentane or cyclohexane.

[0039] Other suitable polyisocyanates for the preparation of crosslinker component B) include any diisocyanates, triisocyanates, and / or polyisocyanates with araliphatically and / or aromatically bound isocyanate groups. For the purposes of the present invention, araliphatically bound isocyanate groups are understood to be isocyanate groups that are bonded to an aromatic ring via an optionally branched alkylene radical, preferably a methylene radical, while aromatically bound isocyanate groups are understood to be those that are bonded directly to an aromatic ring.

[0040] Suitable polyisocyanates of this type for preparing the crosslinking component B) are any araliphatic and / or aromatic diisocyanates and triisocyanates which can be obtained in various ways, for example by phosgenation in the liquid or gas phase or by a phosgene-free route, such as by thermal urethane cleavage, preferably those in the molecular weight range 160 to 600, such as, for example, B. 1,3- and 1,4-bis(isocyanatomethyl)benzene (xylylene diisocyanate, XDI), 1,3- and 1,4-bis(2-isocyanatopropan-2-yl)benzene (tetramethylxylylene diisocyanate, TMXDI), 1,3-bis(isocyanatomethyl)-4-methylbenzene, 1,3-bis(isocyanatomethyl)-4-ethylbenzene, 1,3-bis(isocyanatomethyl)-5-methylbenzene, 1,3-bis(isocyanatomethyl)-4,5-dimethylbenzene, 1,4-bis(isocyanatomethyl)-2,5-dimethylbenzene, 1,4-bis(isocyanatomethyl)-2,3,5,6-tetramethylbenzene, 1,3-bis(isocyanatomethyl)-5-tert-butylbenzene, 1,3-bis(isocyanatomethyl)-4-chlorobenzene, 1,3-bis(isocyanatomethyl)-4,5-dichlorobenzene, 1,3-bis(isocyanatomethyl)-2,4,5,6-tetrachlorobenzene, 1,4-bis(isocyanatomethyl)-2,3,5,6-tetrachlorobenzene, 1,4-bis(isocyanatomethyl)-2,3,5,6-tetrabromobenzene, 1,4-bis(2-isocyanatoethyl)benzene and 1,4-bis(isocyanatomethyl)naphthalene, 1,2-, 1,3- and 1,4-diisocyanatobenzene (phenylene diisocyanate), 2,4- and 2,6-diisocyanatotoluene (toluene diisocyanate, TDI), 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, the isomeric diethylphenylene diisocyanates, diisopropylphenylene diisocyanates, diisododecylphenylene diisocyanates and biphenyl diisocyanates, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 2,2'-, 2,4'- and 4,4'-diisocyanatodiphenylmethane (MDI), 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diisocyanatodiphenylethane, 1,5-diisocyanatonaphthalene (NDI), diphenyl ether diisocyanate, ethylene glycol diphenyl ether diisocyanate, Diethylene glycol diphenyl ether diisocyanate, 1,3-propylene glycol diphenyl ether diisocyanate, benzophenone diisocyanate, triisocyanatobenzene, 2,4,6-triisocyanatotoluene, trimethylbenzene triisocyanate, diphenylmethane 2,4,4'-triisocyanate,3-methyldiphenylmethane-4,6,4'-triisocyanate, the isomeric naphthalene triisocyanates and methylnaphthalene diisocyanates, triphenylmethane triisocyanate, 2,4-diisocyanato-1-[(5-isocyanato-2-methylphenyl)methyl]benzene, 4-methyldiphenylmethane-3,5,2',4',6'-pentaisocyanate or mixtures of at least two such diisocyanates.

[0041] Suitable polyisocyanates for the production of the crosslinking component B) are also the polynuclear homologs of diisocyanatodiphenylmethane known as "polymer MDI".

[0042] Particularly suitable aromatic polyisocyanates for preparing the crosslinker component B) are the polyisocyanates having a urethane and / or isocyanurate structure obtainable from monomeric 2,4- and / or 2,6-TDI by reaction with polyols and / or oligomerization, preferably trimerization, which can be prepared by any known processes, for example those described in DE-A 870 400, DE-A 953 012, DE-A 1 090 196, EP-A 0 546 399, CN 105218780, CN 103881050, CN 101717571, US 3 183 112, EP-A 0 416 338, EP-A 0 751 163, EP-A 1 378 529, EP-A 1 378 530, EP-A 2 174 967, JP 63260915 or JP 56059828, or mixtures of at least two such polyisocyanates.

[0043] Finally, suitable polyisocyanates for the preparation of the crosslinker component B) are also those which carry both aromatic and aliphatic isocyanate groups, for example the mixed trimers or allophanates of 2,4- and / or 2,6-TDI with HDI described in DE-A 1 670 667, EP-A 0 078 991, EP-A 0 696 606 and EP-A 0 807 623.

[0044] To produce the crosslinker component B), preference is given to using polyisocyanates with aliphatically and / or cycloaliphatically bound isocyanate groups, which have a monomeric diisocyanate content of less than 1 wt. %, preferably less than 0.5 wt. %, particularly preferably less than 0.3 wt. %, and / or polyisocyanates based on 2,4- and / or 2,6-TDI with a urethane and / or isocyanurate structure, which have a monomeric diisocyanate content of less than 1.5 wt. %, preferably less than 1.0 wt. %, particularly preferably less than 0.5 wt. %, based on the solids content of the polyisocyanate. The residual monomer contents are measured by gas chromatography using an internal standard in accordance with DIN EN ISO 10283:2007-11.

[0045] Particularly preferred polyisocyanates for preparing the crosslinker component B) are isocyanurate group-containing polyisocyanates of the type mentioned with aliphatically and / or cycloaliphatically bound isocyanate groups and TDI polyisocyanates containing isocyanurate and / or urethane groups, in particular low-monomer reaction products of 2,4- and / or 2,6-TDI with 1,1,1-trimethylolpropane (TMP) and optionally further preferably low-molecular weight alcohols, such as diethylene glycol.

[0046] Very particularly preferred polyisocyanates for the preparation of the crosslinker component B) are polyisocyanates based on PDI, HDI, IPDI and / or 4,4'-diisocyanatodicyclohexylmethane.

[0047] The polyisocyanates mentioned above as suitable, preferred, particularly preferred and very particularly preferred as polyisocyanates for preparing the crosslinker component B) preferably have an average NCO functionality of 2.3 to 5.0, preferably of 2.5 to 4.5, and a content of isocyanate groups of 6.0 to 26.0 wt.%, preferably of 8.0 to 25.0 wt.%, particularly preferably 10.0 to 24.0 wt.%.

[0048] To produce the crosslinking component B), at least one polyisocyanate of the type mentioned is reacted with at least one amino-functional alkoxysilane.

[0049] Suitable amino-functional alkoxysilanes are, for example, aminosilanes of the general formula (II) in which R 5< , R 6< and R 7< represent identical or different radicals and each represent a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted aromatic or araliphatic radical having up to 18 carbon atoms, which may optionally contain up to 3 heteroatoms from the series oxygen, sulfur, nitrogen, X represents a linear or branched organic radical having at least 2 carbon atoms, which may optionally contain up to 2 imino groups (-NH-), and R 8< represents hydrogen, a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted aromatic or araliphatic radical having up to 18 carbon atoms or a radical of the formula in which R 5< , R 6< , R 7< and X have the meaning given above.

[0050] Geeignete Aminosilane der allgemeinen Formel (II) sind beispielsweise 3-Aminopropyltrimethoxysilan, 3-Aminopropyltriethoxysilan, 3-Aminopropylmethyldimethoxysilan, 3-Aminopropylmethyldiethoxysilan, 3-Aminopropylethyldiethoxysilan, 3-Aminopropyldimethylethoxysilan, 3-Aminopropyldiisopropylethoxysilan, 3-Aminopropyltripropoxysilan, 3-Aminopropyltributoxysilan, 3-Aminopropylphenyldiethoxysilan, 3-Aminopropylphenyldimethoxysilan, 3-Aminopropyl-tris(methoxyethoxyethoxy)silan, 2-Aminoisopropyltrimethoxysilan, 4-Aminobutyltrimethoxysilan, 4-Aminobutyltriethoxysilan, 4-Aminobutylmethyldimethoxysilan, 4-Aminobutylmethyldiethoxysilan, 4-Aminobutylethyldimethoxysilan, 4-Aminobutylethyldiethoxysilan, 4-Aminobutyldimethylmethoxysilan, 4-Aminobutylphenyldimethoxysilan, 4-Aminobutylphenyldiethoxysilan, 4-Amino(3-methylbutyl)methyldimethoxysilan, 4-Amino(3-methylbutyl)methyldiethoxysilan, 4-Amino(3-methylbutyl)trimethoxysilan, 3-Aminopropylphenylmethyl-n-propoxysilan, 3-Aminopropylmethyldibutoxysilan,3-Aminopropyldiethylmethylsilan, 3-Aminopropylmethylbis(trimethylsiloxy)silan, 11-Aminoundecyltrimethoxysilan, N-Methyl-3-aminopropyltrimethoxysilan, N-Methyl-3-aminopropyltriethoxysilan, N-(n-Butyl)-3-amino-propyltrimethoxysilan, N-(n-Butyl)-3-aminopropyltriethoxysilan, N-(2-Aminoethyl)-3-aminopropyltrimethoxysilan, N-(2-Aminoethyl)-3-aminoisobutylmethyldimethoxysilan, N-(2-Aminoethyl)-3-aminopropylmethyldimethoxysilan, N-(2-Aminoethyl)-3-aminopropyltris(2-ethylhexoxy)silan, N-(6-Aminohexyl)-3-aminopropyltrimethoxysilan, N-Benzyl-N-(2-aminoethyl)-3-aminopropyltrimethoxysilan, Bis(3-trimethoxysilylpropyl)amin, Bis(3-triethoxysilylpropyl)amin, (Aminoethylaminomethyl)-phenethyltrimethoxysilan, N-Vinylbenzyl-N-(2-aminoethyl)-3-aminopropylpolysiloxan, N-Vinylbenzyl-N(2-aminoethyl)-3-aminopro-pylpolysiloxan, 3-Ureidopropyltriethoxysilan, 3-(m-Aminophenoxy)-propyltrimethoxysilan, m- und / oder p-Aminophenyltrimethoxysilan, 3-(3-Aminopropoxy)-3,3-dimethyl-1-propenyltrimethoxysilan,3-Aminopropylmethylbis(trimethylsiloxy)silane, 3-Aminopropyltris(trimethylsiloxy)silane, 3-Aminopropylpentamethyldisiloxane or any mixture of such aminosilanes.

[0051] Preferred aminosilanes of the general formula (II) are those in which R 5< , R 6< and R 7< each represent alkyl radicals having up to 6 carbon atoms and / or alkoxy radicals containing up to 3 oxygen atoms, with the proviso that at least one of the radicals R 5< , R 2< and R 37< represents such an alkoxy radical, X represents a linear or branched alkylene radical having 3 or 4 carbon atoms, and R 8< represents a saturated, linear or branched, aliphatic or cycloaliphatic radical having up to 6 carbon atoms or a radical of the formula in which R 5< , R 6< , R 7< and X have the meaning given above.

[0052] Particularly preferred aminosilanes of the general formula (II) are those in which R 5< , R 6< and R 7< each represent methyl, methoxy and / or ethoxy, with the proviso that at least one of the radicals R 1< , R 2< and R 3< represents a methoxy or ethoxy radical, X represents a propylene radical (-CH 2 -CH 2 -CH 2 -), and R 8< represents a linear alkyl radical having up to 4 carbon atoms or a radical of the formula in which R 5< , R 6< , R 7< and X have the meaning given above.

[0053] Particularly preferred aminosilanes of the general formula (II) are N-methyl-3-aminopropyltrimethoxysilane, N-methyl-3-aminopropyltriethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, N-(n-butyl)-3-aminopropyltriethoxysilane, bis(3-trimethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)amine, or mixtures of at least two such aminosilanes. Suitable starting compounds B) are, for example, also aminosilanes of the general formula (III) in which R 5< , R 6< and R 7< have the meaning given for formula (II), X represents a linear or branched organic radical having at least 2 carbon atoms and R 9< and R 10< are independently saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or aromatic organic radicals having 1 to 18 carbon atoms, which are substituted or unsubstituted and / or have heteroatoms in the chain.

[0054] These aminosilanes of the general formula (III) are the known silane-functional aspartic acid esters, as can be obtained according to the teaching of EP-A 0 596 360 by reacting aminosilanes carrying primary amino groups with fumaric acid esters and / or maleic acid esters.

[0055] Suitable starting compounds for the preparation of aminosilanes of the general formula (III) are therefore in principle any aminosilanes of the general formula (II) in which R 5< , R 6< , R 7< and X have the meaning given for formula (II) and R 8< is hydrogen.

[0056] These are reacted with fumaric acid diesters and / or maleic acid diesters of the general formula (IV) R 9< OOC-CH=CH-COOR 10< (IV) in which the radicals R 9< and R 10< represent identical or different radicals and are organic radicals having 1 to 18, preferably 1 to 9, particularly preferably 1 to 4, carbon atoms.

[0057] Preferred aminosilanes of the general formula (III) are reaction products of aminosilanes of the general formula (II), in which R 5< , R 6< and R 7< each represent methyl, methoxy and / or ethoxy, with the proviso that at least one of the radicals R 5< , R 6< and R 7< represents a methoxy or ethoxy radical, X represents a propylene radical (-CH 2 -CH 2 -CH 2 -), and R 8< represents hydrogen, with

[0058] Fumaric acid diesters and / or maleic acid diesters of the general formula (IV), in which the radicals R 9< and R 10< represent identical or different radicals and represent a methyl, ethyl, n-butyl or 2-ethylhexyl radical.

[0059] Particularly preferred aminosilanes of the general formula (III) are reaction products of 3-aminopropyltrimethoxysilane and / or 3-aminopropyltriethoxysilane with diethyl maleate.

[0060] Suitable amino-functional alkoxysilanes for the preparation of the crosslinking component B) are, for example, aminosilanes of the general formula (V) in which R 5< , R 6< and R 7< have the meaning given for formula (II), X represents a linear or branched organic radical having at least 2 carbon atoms and R 11< represents a saturated linear or branched, aliphatic or cycloaliphatic organic radical having 1 to 8 carbon atoms.

[0061] These aminosilanes of the general formula (V) are the known silane-functional alkylamides, as can be obtained, for example, by the processes disclosed in US 4,788,310 and US 4,826,915 by reacting aminosilanes carrying primary amino groups with alkylcarboxylic acid alkyl esters with elimination of alcohol.

[0062] Suitable starting compounds for the preparation of aminosilanes of the general formula (IV) are therefore basically any aminosilanes of the general formula (II) in which R 5< , R 6< , R 7< and X have the meaning given above and R 8< is hydrogen.

[0063] These are reacted with alkylcarboxylic acid alkyl esters of the general formula (VI) R 11< -COOR 12< (VI), implemented in which R 11< represents hydrogen or a saturated linear or branched, aliphatic or cycloaliphatic organic radical having 1 to 8 carbon atoms and R 12< represents a saturated aliphatic organic radical having 1 to 4 carbon atoms.

[0064] Preferred aminosilanes of the general formula (V) are reaction products of aminosilanes of the general formula (II), in which R 5< , R 6< and R 7< each represent methyl, methoxy and / or ethoxy, with the proviso that at least one of the radicals R 1< , R 2< and R 3< represents a methoxy or ethoxy radical, X represents a propylene radical (-CH 2 -CH 2 -CH 2 -), and R 8< represents hydrogen, with

[0065] Formic acid alkyl esters of the general formula (VI), in which R 11< represents hydrogen and R 12< represents a saturated aliphatic organic radical having 1 to 4 carbon atoms.

[0066] Particularly preferred aminosilanes of the general formula (V) are reaction products of 3-aminopropyltrimethoxysilane and / or 3-aminopropyltriethoxysilane with methyl formate and / or ethyl formate.

[0067] The preparation of crosslinker component B) from at least one polyisocyanate with at least one amino-functional alkoxysilane is known in principle. It can be carried out, for example, by one of the processes described in WO 2008 / 074489, WO 2008 / 074490, WO 2010 / 149236, WO 2014 / 086530, or WO 2009 / 156148 by reaction at temperatures of 20 to 200°C, preferably 30 to 160°C, particularly preferably 35 to 120°C, while maintaining an equivalent ratio of isocyanate groups to isocyanate-reactive groups of 50:1 to 1.05:1, preferably 20:1 to 1.25:1, particularly preferably 10:1 to 1.5:1.

[0068] The reaction can be carried out without the use of catalysts. However, to accelerate the reaction, it can be advantageous to use suitable catalysts. Suitable catalysts are, in particular, the conventional catalysts known from polyurethane chemistry. Examples include tertiary amines such as triethylamine, tributylamine, dimethylbenzylamine, diethylbenzylamine, pyridine, methylpyridine, dicyclohexylmethylamine, dimethylcyclohexylamine, N,N,N',N'-tetramethyldiaminodiethyl ether, bis(dimethylaminopropyl)urea, N-methyl- orN-Ethylmorpholin, N-Cocomorpholin, N-Cyclohexylmorpholin, N,N,N',N'-Tetramethylethylendiamin, N,N,N',N'-Tetramethyl-1,3-butandiamin, N,N,N',N'-Tetramethyl-1,6-hexandiamin, Pentamethyldiethylentriamin, N-Methylpiperidin, N-Dimethylaminoethylpiperidin, N,N'-Dimethylpiperazin, N-Methyl-N'-dimethylaminopiperazin, 1,2-Dimethylimidazol, 2-Methylimidazol, N,N-Dimethylimidazol-β-phenylethylamin, 1,4-Diazabicyclo-(2,2,2)-octan (DABCO) und Bis-(N,N-dimethylaminoethyl)adipat, Amidine, wie z. B. 1,5-Diazabicyclo[4.3.0]nonen (DBN), 1,8-Diaza-bicyclo(5.4.0)undecen-7 (DBU) und 2,3-Dimethyl-3,4,5,6-tetrahydropyrimidin, Alkanolaminverbindungen, wie z. B. Triethanolamin, Triisopropanolamin, N-Methyl-diethanolamin, N-Ethyl-diethanolamin, Dimethylaminoethanol und 2-(N,N-Dimethylaminoethoxy)ethanol, N,N',N"-Tris-(dialkylaminoalkyl)hexahydrotriazine, wie z. B. N,N',N"-Tris-(dimethylaminopropyl)-s-hexahydrotriazin, Bis(dimethylaminoethyl)ether sowie Metallsalze, wie z. B.inorganic and / or organic compounds of iron, lead, bismuth, zinc, and / or tin in the usual oxidation states of the metal, for example iron(II) chloride, iron(III) chloride, bismuth(III)-bismuth(III)-2-ethylhexanoate, bismuth(III) octoate, bismuth(III) neodecanoate, zinc chloride, zinc 2-ethylcaproate, tin(II) octoate, tin(II) ethylcaproate, tin(II) palmitate, dibutyltin(IV) dilaurate (DBTL), dibutyltin(IV) dichloride or lead octoate.

[0069] Preferred catalysts to be used are tertiary amines, amidines and tin compounds of the type mentioned.

[0070] Particularly preferred catalysts are 1,4-diazabicyclo-(2,2,2)-octane (DABCO), 1,5-diazabicyclo[4.3.0]nonene (DBN), 1,8-diazabicyclo(5.4.0)undecen-7 (DBU) and dibutyltin(IV) dilaurate (DBTL).

[0071] The catalysts mentioned as examples can be used individually or in the form of any mixtures with one another in the preparation of the crosslinking component B) and are used, if at all, in amounts of 0.001 to 1.0 wt.%, preferably 0.01 to 0.5 wt.%, calculated as the total amount of catalysts used based on the total amount of the polyisocyanates and silane compounds used as starting compounds.

[0072] The crosslinker component B) can be prepared from at least one polyisocyanate with at least one amino-functional alkoxysilane without solvents. However, suitable solvents that are inert toward the reactive groups of the starting components can also be used. Suitable solvents include, for example, the conventional paint solvents known per se, such as:Ethyl acetate, butyl acetate, ethylene glycol monomethyl or ethyl ether acetate, 1-methoxypropyl-2-acetate, 3-methoxy-n-butyl acetate, acetone, 2-butanone, 4-methyl-2-pentanone, cyclohexanone, toluene, xylene, chlorobenzene, white spirit, higher substituted aromatics, as are sold, for example, under the names Solventnaphtha, Solvesso ®< , Isopar ®< , Nappar ®< (Deutsche EXXON CHEMICAL GmbH, Cologne, DE) and Shellsol ®< (Deutsche Shell Chemie GmbH, Eschborn, DE), but also solvents such as propylene glycol diacetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol ethyl and butyl ether acetate, N-methylpyrrolidone and N-methylcaprolactam, or any mixtures of such solvents.

[0073] The course of the reaction can be monitored in the process according to the invention by, for example, titrimetric determination of the NCO content.

[0074] Irrespective of the type and amount of the starting compounds used in their preparation, the at least one polyisocyanate and the at least one amino-functional alkoxysilane, the crosslinker components B) for the coating compositions according to the invention are clear, virtually colorless polyisocyanates containing silane groups which, in solvent-free form, generally have color numbers of less than 120 APHA, preferably of less than 80 APHA, particularly preferably of less than 60 APHA, and an NCO content of 1.3 to 24.9% by weight, preferably 4.0 to 23.5% by weight, particularly preferably 5.0 to 21.0% by weight, and an average NCO functionality of 1.0 to 4.9, preferably of 1.8 to 4.8, particularly preferably of 2.0 to 4.0.

[0075] Preferred crosslinker components B) for the coating compositions according to the invention are reaction products of polyisocyanurate polyisocyanates based on PDI and / or HDI with N-(n-butyl)-3-aminopropyltrimethoxysilane, bis(3-trimethoxysilylpropyl)amine or mixtures of N-(n-butyl)-3-aminopropyltrimethoxysilane and bis(3-trimethoxysilylpropyl)amine in a molar ratio of 2.5 : 97.5 to 97.5 : 2.5, in particular of 5 : 95 to 95 : 5, preferably of 10 : 90 to 90 : 10, particularly preferably of 20 : 80 to 80 : 20, very particularly preferably of 30 : 70 to 70 : 30, in which 5 to 95%, preferably 10 to 90%, particularly preferably 15 to 85% of the isocyanate groups originally present in the polyisocyanate were converted to urea groups.

[0076] If desired, the crosslinker components B) can also be used in the coating compositions of the invention in the form of one-component PU baking systems, blocked with isocyanate blocking agents known per se from polyurethane chemistry. Suitable blocking agents for this purpose include, for example, diethyl malonate, acetoacetic ester, activated cyclic ketones such as cyclopentanone-2-carboxymethyl ester and carboxyethyl ester, acetone oxime, butanone oxime, ε-caprolactam, 3,5-dimethylpyrazole, 1,2,4-triazole, dimethyl-1,2,4-triazole, imidazole, benzyl tert-butylamine, or any mixtures of these blocking agents.

[0077] The coating compositions according to the invention contain at least one catalyst C) for crosslinking silane groups. These are any compounds capable of accelerating the hydrolysis and condensation of alkoxysilane groups, or preferably thermally induced silane condensation.

[0078] Suitable catalysts C) are, for example, acids such as, for example, organic carboxylic acids, sulfuric acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, dodecylbenzenesulfonic acid, acetic acid, trifluoroacetic acid, phosphoric acid monoesters and phosphoric acid diesters, such as, for example, dibutyl phosphate, 2-ethylhexyl phosphoric acid ester, phenyl phosphoric acid ester and bis(2-ethylhexyl) phosphoric acid ester, as well as phosphonic acid diesters and diphosphonic acid diesters, as described, for example, in WO 2007 / 033786.

[0079] Also suitable as catalysts C) are bases, such as the N-substituted amidines 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and 1,5-diazabicyclo[5.4.0]undec-7-ene (DBU), or metal salts and metal chelates, such as tetraisopropyl titanate, tetrabutyl titanate, titanium(IV) acetylacetonate, aluminum tri-sec-butylate, aluminum acetylacetonate, aluminum triflate, tin triflate or zirconium ethyl acetoacetate, as described, for example, in WO 2006 / 042658.

[0080] Suitable catalysts C) also include phosphoric and phosphonic esters of the above-mentioned type, which are present in a form blocked with amines, preferably with tertiary amines. Particularly preferred catalysts of this type are those which, in the temperature range of the curing of automotive topcoats and clearcoats, for example in the range of 100 to 150°C, release the acidic phosphoric and phosphonic esters, which are the actually active catalysts, with elimination of the blocking amine. Suitable amine-blocked phosphoric acid catalysts C) are described, for example, in WO 2008 / 074489 and WO 2009 / 077180.

[0081] Also suitable catalysts C) are organic sulfonic acids of the type mentioned above, which are used in blocked form, for example in amine-neutralized form or as adducts to epoxides, as described in DE 2 356 768 B1, and release the catalytically active sulfonic acids again above 100°C.

[0082] Other catalysts C) suitable for crosslinking silane groups are also tetraalkylammonium carboxylates, such as tetramethylammonium formate, tetramethylammonium acetate, tetramethylammonium propionate, tetramethylammonium butyrate, tetramethylammonium benzoate, tetraethylammonium formate, tetraethylammonium acetate, tetraethylammonium propionate, tetraethylammonium butyrate, tetraethylammonium benzoate, tetrapropylammonium formate, tetrapropylammonium acetate, tetrapropylammonium propionate, tetrapropylammonium butyrate, tetrapropylammonium benzoate, tetrabutylammonium formate, tetrabutylammonium acetate, tetrabutylammonium propionate, tetrabutylammonium butyrate and / or tetrabutylammonium benzoate.

[0083] Catalysts C) suitable for crosslinking silane groups are also quaternary ammonium and phosphonium polyfluorides, as known, for example, from EP-A0 798 299, EP-A0 896 009 and EP-A0 962 455 as trimerization catalysts for isocyanate groups.

[0084] Finally, suitable catalysts C) are also zinc amidine complexes, which can be prepared according to the process of WO 2014 / 016019 by reacting one or more zinc(II)biscarboxylates with amidines.

[0085] Preferred catalysts C) for crosslinking silane groups are acidic phosphoric acid esters, phosphonic acid esters, and sulfonic acids of the type mentioned, which may optionally be present in amine-blocked form, as well as tetraalkylammonium carboxylates of the type mentioned. Particularly preferred catalysts C) are amine-blocked phosphoric acid esters and sulfonic acids, as well as the tetraalkylammonium carboxylates mentioned. Very particularly preferred catalysts C) are amine-blocked phenyl phosphoric acid esters and bis(2-ethylhexyl) phosphoric acid esters, tetraethylammonium benzoate, and tetrabutylammonium benzoate.

[0086] In addition to the catalysts C) for silane crosslinking mentioned above as examples, the coating compositions according to the invention can optionally also contain urethanization catalysts customary in isocyanate chemistry which accelerate the reaction of the isocyanate groups of the crosslinker component B) with the hydroxyl groups of the polyol component A), such as, for example, tert. Amines such as triethylamine, pyridine, methylpyridine, benzyldimethylamine, N,N-endoethylenepiperazine, N-methylpiperidine, pentamethyldiethylenetriamine, N,N-dimethylaminocyclohexane, N,N'-dimethylpiperazine or metal salts such as iron(III) chloride, zinc chloride, zinc 2-ethylcaproate, tin(II) octanoate, tin(II) ethylcaproate, dibutyltin(IV) dilaurate, zirconium(IV) isopropylate, zirconium(IV) n-butylate, zirconium(IV) 2-ethylhexanoate, zirconyl octanoate, bismuth(III) 2-ethylhexanoate, bismuth(III) octoate or molybdenum glycolate.

[0087] The catalysts C) are used in the coating compositions according to the invention as individual substances or in the form of any desired mixtures with one another in amounts of 0.005 wt.% up to 5 wt.%, preferably from 0.005 wt.% up to 2 wt.%, particularly preferably from 0.005 wt.% up to 1 wt.%, calculated as the sum of all catalysts C) used and based on the total amount of polyol component A) and crosslinker component B).

[0088] The coating compositions according to the invention may optionally contain further auxiliaries and additives D). These are, in particular, auxiliaries and additives known to those skilled in the art from coating technology, such as solvents, UV stabilizers, antioxidants, water scavengers, leveling agents, rheology additives, slip additives, defoamers, fillers, and / or pigments.

[0089] To reduce the processing viscosity, the coating compositions according to the invention can be diluted, for example, with conventional organic solvents D1). Suitable solvents for this purpose include, for example, the coating solvents already described above as solvents to be used optionally in the preparation of the crosslinker component B), which are chemically inert toward the reactive groups of the coating composition constituents and have a water content of at most 1.0 wt. %, particularly preferably at most 0.5 wt. %, based on the solvent used.

[0090] Suitable UV stabilizers D2) can preferably be selected from the group consisting of piperidine derivatives, such as 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-1,2,2,6,6-pentamethylpiperidine, bis-(2,2,6,6-tetra-methyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-1,4-piperidinyl) sebacate, bis-(2,2,6,6-tetramethyl-4-piperidyl) suberate, bis-(2,2,6,6-tetramethyl-4-piperidyl) dodecanedioate; benzophenone derivatives such as 2,4-dihydroxy, 2-hydroxy-4-methoxy, 2-hydroxy-4-octoxy, 2-hydroxy-4-dodecyloxy or 2,2'-dihydroxy-4-dodecyloxy-benzophenone; Benztriazole derivatives, such as2-(2H-Benzotriazol-2-yl)-4,6-di-tert-pentylphenol, 2-(2H-Benzotriazol-2-yl)-6-dodecyl-4-methylphenol, 2-(2H-Benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-(5-Chlor-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4-methylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2-(2H-Benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol, Isooctyl-3-(3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxyphenylpropionat), 2-(2H-Benzotriazol-2-yl)-4,6-bis(1,1-dimethylethyl)phenol, 2-(2H-Benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-(5-Chlor-2H-benzotriazol-2-yl)-4,6-bis(1,1-dimethylethyl)phenol; Oxalaniliden, wie z.B. 2-Ethyl-2'-ethoxy- oder 4-Methyl-4'-methoxyoxalanilid; Salicylsäureestern, wie z.B. Salicylsäurephenylester, Salicylsäure-4-tert-butylphenylester, Salicylsäure-4-tert-octylphenylester; Zimtsäureesterderivaten, wie z.B.Methyl α-cyano-β-methyl-4-methoxycinnamate, butyl α-cyano-β-methyl-4-methoxycinnamate, ethyl α-cyano-β-phenylcinnamate, isooctyl α-cyano-β-phenylcinnamate; and malonic ester derivatives, such as dimethyl 4-methoxybenzylidenemalonate, diethyl 4-methoxybenzylidenemalonate, and dimethyl 4-butoxybenzylidenemalonate. These preferred UV stabilizers can be used individually or in any combination.

[0091] If appropriate, one or more of the UV stabilizers D2) mentioned by way of example are added to the coating compositions according to the invention, preferably in amounts of 0.001 to 3.0% by weight, particularly preferably 0.01 to 2% by weight, calculated as the total amount of UV stabilizers used, based on the total amount of polyisocyanate component A) and hydroxy-functional binder component B).

[0092] Suitable antioxidants D3) are preferably sterically hindered phenols, which can preferably be selected from the group consisting of 2,6-di-tert-butyl-4-methylphenol (ionol), pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triethylene glycol bis(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, 2,2'-thio-bis(4-methyl-6-tert-butylphenol) and 2,2'-thiodiethyl bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. These can be used individually or in any combination with one another if required.

[0093] These antioxidants D3) are preferably used in amounts of 0.01 to 3.0 wt.%, particularly preferably 0.02 to 2.0 wt.%, calculated as the total amount of antioxidants used based on the total amount of polyol component A) and crosslinker component B).

[0094] To prevent premature crosslinking of the silane groups in the coating compositions according to the invention, the addition of water scavengers D4), for example, orthoformic esters such as triethyl orthoformate, or vinylsilanes such as vinyltrimethoxysilane, may be advantageous. These water scavengers are used, if at all, in amounts of 0.01 wt.% to 5 wt.%, preferably 0.01 wt.% to 2 wt.%, based on the total amount of polyol component A) and crosslinker component B).

[0095] To improve substrate wetting, the coating compositions according to the invention may optionally contain suitable flow control agents D5), for example, organically modified siloxanes, such as polyether-modified siloxanes, polyacrylates, and / or fluorosurfactants. These flow control agents are used, if at all, in amounts of 0.01 wt.% to 3 wt.%, preferably 0.01 wt.% to 2 wt.%, particularly preferably 0.05 to 1.5 wt.%, based on the total amount of polyol component A) and crosslinker component B).

[0096] To optimize application reliability, in particular to prevent the paint from running down vertical surfaces of the objects to be coated during application, the coating compositions according to the invention can optionally contain suitable rheology additives D6), for example colloidal silicas, very finely divided bentonites, microcrystalline polyethylene waxes, polyamide dispersions and / or crystalline ureas. Preferred rheology additives D6) are crystalline ureas, such as the reaction product of two moles of benzylamine with one mole of HDI, which are usually added to the polyol component as sag control agents (SCA). A number of different polyols already modified with SCA, for example based on polyester or polyacrylate, are commercially available on the market and can be used as a component of the polyol component A) in the coating compositions according to the invention to improve the rheological properties.

[0097] The slip additives, defoamers, fillers, and / or pigments optionally present in the coating compositions according to the invention as further auxiliaries and additives D) are known to the person skilled in the art and, if used at all, are used in the amounts customary in coating technology. A detailed overview of such suitable auxiliaries and additives can be found, for example, in Bodo Müller, "Additive kompakt," Vincentz Network GmbH & Co. KG (2009).

[0098] To produce the coating compositions according to the invention, the described components A), B), C), and optionally D) are thoroughly mixed in any desired order, one after the other or together, preferably with the aid of suitable mixing units, until a homogeneous solution is obtained. The polyol component A), which contains at least one polyester polyol A1) prepared using TACD, and the crosslinker component B) are typically used in amounts such that each isocyanate group of the crosslinker component B) accounts for 0.5 to 3.0, preferably 0.6 to 2.0, particularly preferably 0.8 to 1.6 hydroxyl groups of the polyol component A).

[0099] The catalyst component C) and any other auxiliaries and additives D) to be used can optionally be added to either the polyol component A) or a component A1) and / or optionally A2) of the polyol component and / or the crosslinker component B) before the actual mixing of the reactive components, wherein the catalyst component C) is particularly preferably added to the polyol component A) to avoid premature silane condensation.

[0100] The application of the coating compositions according to the invention thus obtained, which contain polyisocyanates containing silane groups as crosslinking agents, can be carried out by methods known per se, for example by spraying, brushing, dipping, flow coating or by means of rollers or doctor blades in one or more layers.

[0101] Any substrate can be considered, such as metal, wood, glass, stone, ceramic materials, concrete, hard and flexible plastics, textiles, leather and paper, which can also be coated with conventional primers, filler coats, base coats and / or clear coats before coating.

[0102] The coating compositions of the invention are preferably used in applications where high demands are placed on a coating in terms of optical quality and resistance to mechanical scratching. These include, in particular, decorative, protective, and / or effect-imparting, highly scratch-resistant coatings and finishes for motor vehicle bodies, such as motorcycles, buses, trucks, or cars, or parts thereof. The coating compositions of the invention are particularly suitable for the production of coatings and finishes, in particular clearcoats, in automotive refinishing and in automotive OEM finishing.

[0103] The coating compositions according to the invention are preferably also used in the clear or topcoat layer of multi-layer structures, in particular in multi-stage coating processes in which a pigmented basecoat layer and then a layer of the coating composition according to the invention are applied to an optionally pre-coated substrate.

[0104] Another object of the present invention relates to a process for coating surfaces, comprising the steps a) applying the coating composition according to the invention to a substrate; and b) curing the coating composition.

[0105] The coating compositions according to the invention are preferably processed by spray application methods, such as compressed air spraying, airless spraying, high-speed rotation, electrostatic spray application (ESTA), optionally combined with hot spray application, such as hot air spraying. In these spray application methods, the individual components of the coating compositions according to the invention, in particular the mutually reactive components A) and B), are preferably mixed immediately before processing and can advantageously be carried out in so-called 2-component systems.

[0106] The curing of the coating compositions according to the invention can take place immediately after application or after a specific flash-off time has been observed. The flash-off time serves, for example, to allow the coating layers to flow and degas or to evaporate volatile components, such as solvents. The required flash-off time can be specifically controlled, for example, by applying elevated temperatures and / or reducing humidity.

[0107] The final curing of the applied coating compositions according to the invention is finally carried out by customary and known methods, such as heating in a circulating air oven, irradiation with IR lamps or near infrared (NIR radiation), preferably in a temperature range of 30 to 200°C, particularly preferably 40 to 190°C and very particularly preferably 50 to 180°C for a time of 1 minute up to 12 hours, particularly preferably 2 minutes up to 6 hours and very particularly preferably 3 minutes to 4 hours.

[0108] The process is preferably used for coating surfaces in the application areas mentioned above.

[0109] The coatings produced in this way from the coating compositions according to the invention, which are preferably clear coats, are characterized by extraordinarily high scratch resistance as well as very good solvent and chemical resistance.

[0110] A further object of the present invention is the use of the coating compositions according to the invention for producing coatings and paints.

[0111] These coatings and varnishes are preferably used to produce clear coats.

[0112] Particular preference is given to using the coating compositions according to the invention for producing coatings and finishes in automotive refinishing and automotive OEM finishing.

[0113] The present invention further relates to substrates coated with one or more coating compositions according to the invention.

[0114] The substrate is preferably selected from the group consisting of metal, wood, wood materials, glass, stone, ceramic materials, mineral building materials, hard and flexible plastics, textiles, leather and paper.

[0115] The following examples serve to illustrate the invention. They are not intended to limit the scope of the claims in any way. Examples

[0116] Unless otherwise stated, all percentages are based on weight.

[0117] The NCO content was determined titrimetrically according to DIN EN ISO 11909:2007-05.

[0118] All viscosity measurements were performed using a Physica MCR 51 rheometer from Anton Paar Germany GmbH (DE) according to DIN EN ISO 3219:1994-10 at a shear rate of 250 s-1.

[0119] The flow time was determined according to DIN EN ISO 2431:2012-03 using an ISO flow cup with a 5 mm nozzle.

[0120] To produce automotive clearcoats, the polyols described below were each homogeneously mixed with a 10% solution of a commercially available leveling additive in butyl acetate (BYK 331; BYK-Chemie GmbH, Wesel, Germany), the light stabilizers Tinuvin 292 and Tinuvin 384-2, each as a 50% solution in MPA (BASF SE, Ludwigshafen, Germany), and, in the case of the inventive formulations from Examples 2 and 4, tetraethylammonium benzoate (Sigma-Aldrich Chemie GmbH, Munich, Germany) as a 50% solution in butanol as catalyst C) by vigorous stirring at room temperature. The respective polyisocyanates were stirred into this base coat component, and the solids content of the finished coating compositions was adjusted to a flow time of approximately 28 seconds with methoxypropyl acetate.

[0121] Table 1 shows the compositions of the individual formulations.

[0122] To determine the pendulum damping according to König (according to DIN EN ISO 1522) and to test the solvent resistance, the coating agents were applied to glass plates using a gravity feed gun and, after 10 minutes of flash-off at room temperature, cured within 22 minutes at 140°C.

[0123] To test the coatings for solvent resistance, small amounts of the solvents xylene (X), 1-methoxypropyl-2-acetate (MPA), ethyl acetate (EA), and acetone (A) were placed in test tubes and a cotton swab placed over the opening to create a solvent-saturated atmosphere inside the test tubes. The test tubes were then placed with the cotton swab onto the surface of the coating film applied to glass and left there for 5 minutes. After wiping off the solvent, the film was tested for destruction / softening / loss of adhesion and rated (0 = no change, 5 = film completely dissolved). The ratings for the four solvents are given in the order X, MPA, EA, and A as four consecutive numbers.

[0124] The scratch resistance as well as the resistance to fuels and chemicals was tested on the complete OEM multi-layer structure on sheet steel.

[0125] For this purpose, the coating materials were applied as clear coats using a gravity-feed gun to e-coated panels that had previously been coated with a commercially available 1K OEM hydro-filler and a conventional black 1K OEM hydro-basecoat. While the hydro-filler was fully cured by baking for 20 minutes at 165°C, the hydro-basecoat was only pre-cured for 10 minutes at 80°C. After applying the clear coats, the basecoat and clearcoat layers were cured together for 22 minutes at 140°C.

[0126] Wet scratching was carried out using an Amtec-Kistler laboratory washing system in accordance with DIN EN ISO 20566, and dry scratching was carried out using a crockmeter and polishing paper in accordance with DIN 55654, Method A (friction pin geometry cuboid, base area (22 mm x 22 mm), test force (22.0 ± 0.5) N).

[0127] The gloss of the resulting coatings was measured reflectometrically according to DIN EN ISO 2813 at a 20° angle.

[0128] The gloss loss is expressed in Gloss Units (GU) after scratching (10 cycles). The lower the gloss loss in GU, the more resistant the coating is to wet scratching.

[0129] A FAM test was carried out as a measure of resistance to fuels. A small cotton ball soaked in FAM solution according to DIN 51604-1 as the test substance was placed on the paint surface and covered with a watch glass to prevent evaporation. After a load period of 10 minutes, the cotton ball soaked in the test substance was removed, the exposed area was dried and immediately inspected visually and manually by feeling and scratching. Softening or discoloration of the paint surface is assessed as follows: 0 = no changes; 1 = swelling ring, surface hard, only visible change / trace of a change in color; 2 = swelling ring, slight softening / slight change in color; 3 = significant softening (possibly slight blistering) / moderate change in color / scratchable; 4 = severe softening (possiblysevere blistering), scratchable down to the substrate / severe color change; 5 = coating completely destroyed without external influence / very severe color change.

[0130] The chemical resistance test using a gradient oven was carried out according to DIN EN ISO 2812-5:2007-05.

[0131] Table 2 shows the results of the application tests in comparison, each determined after a storage time of 24 h at 23°C. Output connections used Desmodur N 3390 BA / SN:

[0132] Aliphatic polyisocyanurate polyisocyanate based on HDI (Covestro Deutschland AG, Leverkusen), 90% solution in n-butyl acetate / solvent naphtha 100 (1:1), NCO content: 19.6%, viscosity at 23°C: 550 mPas. Silane-functional polyisocyanate P1:

[0133] 42.0 parts by weight of a commercially available solvent-free polyisocyanurate polyisocyanate based on HDI (Desmodur N 3300, Covestro Deutschland AG, Leverkusen) with an NCO content of 21.8% and a viscosity of 3000 mPas at 23°C were initially charged with 36.0 parts by weight of n-butyl acetate at 25°C. A mixture of 2.0 parts by weight of N-[3-(trimethoxysilyl)propyl]butylamine and 20.0 parts by weight of bis[3-(trimethoxysilyl)propyl]amine was added over a period of 120 minutes. After stirring for 30 minutes, a polyisocyanate containing silane groups was obtained. The NCO content of the solution was 6.3%, and the viscosity of the 64% solution was 90 mPas at 23°C. Eastman Tetrashield IC3020:

[0134] Polyester polyol based on 2,2,4,4-tetramethylcyclobutane-1,3-diol (TMCD) (Eastman Chemical Company, Kingsport (TN), US), 75% solution in n-butyl acetate, OH number (based on delivery form): 150 mg KOH / g, viscosity at 23°C: approx. 6000 mPas. Setalux 91767 VX-60:

[0135] Sag control agent-modified polyacrylate polyol (Allnex Germany GmbH, Bitterfeld-Wolfen, DE), 60% solution in solvent naphtha / xylene (76 / 24), OH number (based on delivery form): 90 mg KOH / g. Setalux DA 665 BA / X

[0136] Polyacrylate polyol (Allnex Germany GmbH, Bitterfeld-Wolfen, DE), 65% solution in butyl acetate / xylene (75 : 25), OH number: 150 mg KOH / g (based on delivery form), viscosity at 23°C: approx. 2400 mPas. Table 1 : Clearcoat formulations. All data in parts by weight unless otherwise stated. Example 1 (Comparison) 2 3 (Comparison) 4 5 (Comparison) Component A Eastman Tetrashield IC3020 90,89 60,25 76,43 51,02 --- Setalux 91767 VX-60 --- --- 23,89 15,84 26,11 Setalux DA 665 BA / X --- --- --- --- 96,41 Byk 331, 10% in BA 0,23 0,23 0,23 0,23 0,23 Tinuvin 292, 50% in MPA 2,30 2,30 2,30 2,30 2,30 Tinuvin 384-2, 50% in MPA 3,45 3,45 3,45 3,45 3,45 Tetraethylammonium benzoate, 50% in butanol --- 2,30 --- 2,30 --- Methoxypropyl acetate (MPA) 48,76 22,34 44,64 20,03 29,89 Component B Desmodur N 3390 BA / SN 52,07 --- 52,86 --- 45,41 Polyisocyanate P1) --- 109,13 --- 111,54 --- Methoxypropyl acetate (MPA) 10,50 --- 5,00 --- 41,68 Description Total parts by weight 208,20 200,0 208,8 206,81 245,48 NCO : OH 1 : 1 1 : 1 1 : 1 1 : 1 1 : 1 Solids content during application [%] 57,3 59,6 57,1 57,6 48,6 Table 2 : Test results Example 1 (Comparison) 2 3 (Comparison) 4 5 (Comparison) Tests on glass plate according to description Layer thickness on glass [µm] 51 50 46 51 44 Pendulum hardness [s] 212 209 214 213 204 Solubility 5' (X, MPA, EA, A) (0 - 5) 0024 0000 0022 0001 0024 Tests on the complete body KTL / filler / base coat / Clear coat as described FAM test 10 min. (0 - 5) 2 1 1 1 2 Wet scratching Initial gloss 20° [GU] 86 88 88 88 90 Gloss after scratching 20° [GU] 47 74 55 74 62 Loss of shine after 10 cycles Δ 39 14 33 14 28 Shine after recovery 2h 60°C 20° [GU] 51 77 59 77 81 Residual shine before recovery [rel. %] 55 84 63 84 69 Residual shine after recovery [rel. %] 59 88 67 88 90 Dry scratching Crockmeter (polishing paper) Initial gloss 20° [GU] 86 88 88 88 90 Gloss after scratching 20° [GU] 15 59 30 53 30 Loss of shine after 10 cycles Δ 71 29 58 35 60 Shine after recovery 2h 60°C 20° [GU] 21 68 39 65 77 Residual shine before recovery [rel. %] 17 67 34 60 33 Residual shine after recovery [rel. %] 24 77 44 74 86 Chemical resistance gradient oven tree resin [°C] 42 >68 52 >68 40 Pancreatin [°C] 36 36 40 36 36 Distilled water [°C] 49 50 62 64 >68 Sodium hydroxide solution, 1% [°C] 50 50 54 44 48 Sulfuric acid, 1% [°C] 48 44 45 43 44

[0137] All coatings cured to hard, high-gloss coatings. Compared to the comparative coating from Example 5, which was formulated exclusively with polyacrylate polyols, all coatings containing the polyester polyol based on 2,2,4,4-tetramethylcyclobutane-1,3-diol (Examples 1 to 4, according to the invention and comparison) demonstrated improved chemical resistance. While the comparative coatings from Examples 1 and 3 crosslinked with the standard polyisocyanate exhibited significantly reduced scratch resistance compared to the TMCD-free comparative coating from Example 5, the scratch resistance of the coating films according to the invention (Examples 2 and 4), particularly under wet scratching, was at a similarly high level to that of the standard 2K PUR coating (Example 5). Compared to all comparative coatings, the two coating films according to the invention exhibited the lowest direct scratch resistance (highest residual gloss before recovery) and by far the best solvent resistance and tree resin resistance.

Claims

1. Coating composition containing A) at least one polyol component, B) at least one crosslinker component having free and / or blocked isocyanate groups which is obtained by reaction of at least one polyisocyanate with at least one amino-functional alkoxysilane, optionally C) at least one catalyst for the crosslinking of silane groups, and D) optionally further auxiliaries and additives, characterized in that the polyol component A) comprises at least one polyester polyol A1) prepared using a 2,2,4,4-tetraalkylcyclobutane-1,3-diol (TACD) of the general formula (I) in which the radicals R1, R2, R3 and R4 are independently linear or branched alkyl radicals having up to 8 carbon atoms.

2. Coating composition according to Claim 1, characterized in that the radicals R1, R2, R3 and R4 in general formula (I) are independently linear or branched alkyl radicals having up to 6 carbon atoms, particularly preferably up to 4 carbon atoms.

3. Coating composition according to Claim 1 and 2, characterized in that the radicals R1, R2, R3 and R4 in general formula (I) are each a methyl radical.

4. Coating composition according to any of Claims 1 to 3, characterized in that the preparation of the polyester polyol A1) involves using 2,2,4,4-tetraalkylcyclobutane-1,3-diols (TACDs) of general formula (I) in such amounts that the TACD content in the total amount of polyhydric alcohols used is at least 10 mol%.

5. Coating composition according to any of Claims 1 to 4, characterized in that the polyester polyols A1) have a hydroxyl group content of 1.5% to 15% by weight, an acid number of 0 to 80 mg KOH / g and number-average molecular weights (Mn) of 300 to 10 000 g / mol.

6. Coating composition according to any of Claims 1 to 5, characterized in that the polyol component A) comprises further polyols A2) different from A1), such as for example TACD-free polyester polyols, polyether polyols, polycarbonate polyols and / or polyacrylate polyols, or any mixtures of such polyols, the content of polyester polyols A1) in the overall polyol component A) being at least 10% by weight.

7. Coating composition according to any of Claims 1 to 6, characterized in that the preparation of crosslinker component B) uses isocyanurate group-containing polyisocyanates having aliphatically and / or cycloaliphatically bonded isocyanate groups, and / or isocyanurate group-containing and / or urethane group-containing polyisocyanates based on 2,4- and 2,6-diisocyanatotoluene.

8. Coating composition according to any of Claims 1 to 6, characterized in that the preparation of crosslinker component B) uses polyisocyanates based on 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane and / or 4,4'-diisocyanatodicyclohexylmethane.

9. Coating composition according to any of Claims 1 to 8, characterized in that the preparation of crosslinker component B) uses aminosilanes of the general formula (II) in which R5, R6 and R7 are identical or different radicals and are each a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted aromatic or araliphatic radical which has up to 18 carbon atoms and may optionally contain up to 3 heteroatoms from the group of oxygen, sulfur and nitrogen, X is a linear or branched organic radical which has at least 2 carbon atoms and may optionally contain up to 2 imino groups (-NH-), and R8 is hydrogen, a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted aromatic or araliphatic radical having up to 18 carbon atoms or a radical of the formula in which R5, R6, R7 and X are as defined above.

10. Coating composition according to any of Claims 1 to 9, characterized in that the aminosilanes used for the preparation of crosslinker component B) are N-methyl-3-aminopropyltrimethoxysilane, N-methyl-3-aminopropyltriethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, N-(n-butyl)-3-aminopropyltriethoxysilane, bis(3-trimethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)amine or mixtures of at least two such aminosilanes.

11. Coating composition according to any of Claims 1 to 8, characterized in that the preparation of crosslinker component B) uses aminosilanes of the general formula (III) in which R5, R6 and R7 have the definition given for formula (II) in Claim 9, X is a linear or branched organic radical having at least 2 carbon atoms and R9 and R10 are independently saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or aromatic organic radicals having 1 to 18 carbon atoms that are substituted or unsubstituted and / or have heteroatoms in the chain.

12. Coating composition according to any of Claims 1 to 8, characterized in that the preparation of crosslinker component B) uses aminosilanes of the general formula (V) in which R5, R6 and R7 have the definition given for formula (II) in Claim 9, X is a linear or branched organic radical having at least 2 carbon atoms and R11 is a saturated linear or branched, aliphatic or cycloaliphatic organic radical having 1 to 8 carbon atoms.

13. Coating composition according to any of Claims 1 to 12, characterized in that catalysts C) used are phosphoric esters, phosphonic esters and / or sulfonic acids, which may optionally be in amine-blocked form, and / or tetraalkylammonium carboxylates.

14. Coating composition according to any of Claims 1 to 13, characterized in that catalysts C) used are amine-blocked phenyl phosphate and bis(2-ethylhexyl) phosphate, tetraethylammonium benzoate and tetrabutylammonium benzoate.

15. Use of the coating composition according to any of Claims 1 to 14 for producing coatings.

16. Use of the coating composition according to any of Claims 1 to 14 for producing coatings and paint systems, more particularly clearcoats, in automotive refinishing and automotive OEM finishing.

17. Substrate coated with at least one coating composition according to any of Claims 1 to 14.