Tin-free catalysis of silane-functional polyurethane crosslinkers

Description

[0001] The present invention relates to a composition comprising at least A) an adduct of isocyanatosilanes to hydroxy-functional compounds, B) a tin-free catalyst and C) an aminosilane, as well as a coating agent comprising at least the composition, and the use of the coating agent.

[0002] For the long-lasting protective coating of substrates, two-component polyurethane-based coatings are generally used today. These coatings can cure slowly at ambient temperature and rapidly at elevated temperatures. They typically consist of coating resins and crosslinkers, each equipped with functional groups that react with each other through crosslinking. Due to the strong dependence on temperature and crosslinking rate, and the resulting necessity of using tin-containing catalysts, which are toxicologically problematic, there is a desire to provide alternative coating systems. These systems should ideally be able to cure quickly, primarily at room temperature, in order to save on costly baking technologies and reduce labor costs.High reactivity and high resistance of the cured coatings to chemicals, weathering, and mechanical stress must be guaranteed. Long-established aliphatic two-component polyurethane (PUR) systems serve as a technical reference.

[0003] Such a 2K system is described, for example, in DE 10 2007 013 262 A1. However, these are 2K systems that can only be cured quickly at elevated temperatures above 140°C.

[0004] WO 2014 / 180623 A1 describes a silane-containing coating material which can ensure rapid crosslinking rates solely through the addition of tin-containing compounds at temperatures in the range of 0°C to 40°C.

[0005] The systems known from the prior art have the disadvantage that they either harden at room temperature or elevated temperatures and often contain toxicologically questionable tin compounds to ensure a sufficient crosslinking rate.

[0006] The object of the present invention is to provide a composition which can preferably be cured at temperatures in the range of 0 °C to 40 °C and is tin-free. This object is achieved by coating materials of the present invention.

[0007] The underlying problem of the present invention could be solved by a composition which contains at least A) an adduct of isocyanatosilanes to hydroxy-functional compounds, B) a tin-free catalyst and C) an aminosilane.

[0008] The compositions according to the invention can be used, in particular, as coating agents. It has surprisingly been found that the compositions according to the invention, which contain at least the aforementioned components A), B), and C), lead to stable coatings even at 0°C when used as coating agents. These coating agents according to the invention are single-component (1K) systems that are easy to apply. Due to the low molecular weight of the coating agents, they can be formulated and processed without additional organic solvents for subsequent applications. Thus, it is possible to achieve a VOC content of less than 100 g / l.

[0009] Furthermore, it has surprisingly been shown that the compositions according to the invention, which contain at least the aforementioned components A), B) and C), can also rapidly cure ethoxy-based adducts of isocyanatosilanes to hydroxy-functional compounds at room temperature. Thus, the latent methanol content of the overall system can be reduced and the toxicological system profile further improved.

[0010] Component A) of the composition or coating agent according to the invention consists of adducts of isocyanatosilanes to hydroxy-functional compounds.

[0011] Preferably, the isocyanatosilane is a compound of formula (I) OCN-(alkyl)-Si(alkoxy) 3 (I) wherein the alkyl in the above formula (I) corresponds to a linear or branched alkyl group with 1 to 4 carbon atoms and the alkoxy in the above formula (I) corresponds simultaneously or independently to a methoxy, ethoxy, propoxy or butoxy group, wherein the three alkoxy groups in the compound of formula (I) may each be the same or different from each other.

[0012] All of the previously described possible compounds are suitable as compounds of formula (I) OCN-(alkyl)-Si(alkoxy) 3. However, alkoxy selected from methoxy and ethoxy groups is particularly preferred. The three alkoxy groups in the compound of formula (I) can be identical or different from one another. Preferably, the alkoxy groups are identical, but methoxy groups are not preferred. In a most preferred embodiment, all three alkoxy groups in the compound of formula (I) are ethoxy groups.

[0013] Suitable compounds of formula (I) are in particular isocyanatoalkylalkoxysilanes selected from the group comprising 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltriisopropoxysilane, 2-isocyanatoethyltrimethoxysilane, 2-isocyanatoethyltriethoxysilane, 2-isocyanatoethyltriisopropoxysilane, 4-isocyanatobutyltrimethoxysilane, 4-isocyanatobutyltriethoxysilane, 4-isocyanatobutyltriisopropoxysilane, isocyanatomethyltrimethoxysilane, isocyanatomethyltriethoxysilane, isocyanatomethyltriisopropoxysilane, 3-isocyanatopropyldimethoxyethoxysilane and / or 3-isocyanatopropyldiethoxymethoxysilane.

[0014] Preferably, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyldimethoxyethoxysilane and / or 3-isocyanatopropyldiethoxymethoxysilane, particularly preferably 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyldimethoxyethoxysilane and / or 3-isocyanatopropyldiethoxymethoxysilane as a compound of formula (I) (component A) are used in the compositions or coating materials according to the invention.

[0015] The aforementioned isocyanatosilanes exist as adducts to hydroxy-functional compounds. Suitable hydroxy-functional compounds include monohydric or polyhydric alcohols as well as polyols.

[0016] Suitable hydroxy-functional compounds include, for example, mono-alcohols or polyols, in particular diols, triols, tetrols, and polymers containing hydroxyl groups. In a preferred embodiment, diols, triols, or tetrols, particularly preferably diols or triols, are used as hydroxy-functional compounds.

[0017] In the case of mono-alcohols, these are in particular monofunctional branched or linear alcohols or mixtures thereof with 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, particularly preferably 1 to 9 carbon atoms, in particular methanol, ethanol, propanol and butanol.

[0018] Glycol ethers can also be used as mono-alcohols. Suitable glycol ethers include, in particular, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, 1,1'-oxybis(2-triethylene glycol) monomethyl ether, triethylene glycol monobutyl ether, propylene glycol 1-methyl ether, propylene glycol 2-methyl ether, propylene glycol 1-ethyl ether, and propylene glycol 1-butyl ether.

[0019] Suitable diols include in particular difunctional branched or linear alcohols or mixtures thereof with 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and especially preferably 1 to 10 carbon atoms.

[0020] Trifunctional branched or linear alcohols or mixtures thereof with 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and particularly preferably 1 to 10 carbon atoms, are particularly suitable as triols.

[0021] Tetrafunctional branched or linear alcohols or mixtures thereof with 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and particularly preferably 1 to 10 carbon atoms, are particularly suitable as tetrols.

[0022] Furthermore, polymers containing hydroxyl groups with an OH number of 10 to 500 mg KOH / gram and a number-average molar mass of 250 to 6000 g / mol can be used as hydroxy-functional compounds. These polymers are selected from the group consisting of polyesters, polyethers, polyacrylates, polycarbonates, epoxy resins, cellulose derivatives, FEVE (fluoroethylene vinyl ether), alkyds, and polyurethanes, the polyurethanes preferably consisting of or being formed from polyols and diisocyanate monomers. Preferably, polyesters and / or polyacrylates containing hydroxyl groups with an OH number of 20 to 150 mg KOH / gram and a number-average molar mass of 500 to 6000 g / mol are used.

[0023] The hydroxyl number (OHS) is determined according to DIN EN ISO 4629-2 (2016-12). In this method, the sample is reacted with acetic anhydride in N-methyl-2-pyrrolidone (NMP) in the presence of 4-N-dimethylaminopyridine as a catalyst, whereby the hydroxyl groups are acetylated. One molecule of acetic acid is produced per hydroxyl group, while the subsequent hydrolysis of the excess acetic anhydride yields two molecules of acetic acid. The consumption of acetic acid is determined titrimetrically from the difference between the main value and a blank value obtained in parallel.

[0024] The number-mean molecular weights are determined according to DIN 55672-1 (2016-03) by gel permeation chromatography in tetrahydrofuran as eluent and polystyrene for calibration.

[0025] Furthermore, mixtures of the above-mentioned hydroxyl-functional compounds can also be used.

[0026] In a preferred embodiment, diols, triols or tetrols, particularly preferably diols or triols, are used as hydroxy-functional compounds for the adduct A).

[0027] The preparation of the adducts A) can be carried out solvent-free or using non-protic solvents, and the reaction can be batchwise or continuous. The reaction can be carried out at room temperature, i.e., at temperatures in the range of 20 to 25 °C; however, higher temperatures in the range of 30 to 150 °C, and especially in the range of 50 to 100 °C, are preferred. To accelerate the reaction, catalysts known in urethane chemistry, such as Sn, Bi, Zn and other metal carboxylates, tert-amines such as 1,4-diazabicyclo[2,2,2]octane (DABCO), triethylamine, etc., can be advantageously used. The reaction is preferably carried out in the absence of water and using tin-free catalysts, e.g., Bi-based catalysts.

[0028] The reaction of the isocyanatosilanes and the hydroxy-functional compounds to form adducts A) is carried out in particular such that the ratio of OH groups from the hydroxy-functional compounds to NCO groups from the isocyanatosilanes in adduct A) is from 0.8 : 1 to 1.2 : 1, preferably from 0.9 : 1 to 1.1 : 1, with the stoichiometric reaction (1 : 1) being particularly preferred. In a particularly preferred embodiment, a complete reaction of all OH groups of the hydroxy-functional compounds with NCO groups of the isocyanatosilanes, in particular those of the compounds of formula (I), is achieved.

[0029] Depending on the chosen stoichiometry of both reactants, the resulting adduct A) may still contain free hydroxyl or isocyanate groups. However, the adducts A) are preferably free of NCO groups. In this context, the phrase "free of NCO groups" is to be understood as meaning that the composition or coating according to the invention contains ≤ 0.5% free NCO groups, preferably ≤ 0.05% free NCO groups, more preferably ≤ 0.01% free NCO groups, and most preferably no free NCO groups. The percentage refers to the total amount of NCO groups in the isocyanatosilane used.

[0030] In the aforementioned reaction, the NCO groups of the isocyanatosilanes react with the OH groups of the hydroxy-functional compounds to form NH-CO-O groups, which link the aforementioned compounds together. The resulting adducts A) are liquid, particularly at temperatures at and above 0 °C, even in solvent-free form. They are therefore preferably non-crystallizing, low-molecular-weight compounds.

[0031] The adducts A) are low to high viscosity in solvent-free form, i.e., they have a viscosity in the range of 10 to 40,000 mPa·s, preferably in the range of 50 to 18,000 mPa·s (DIN EN / ISO 3219 (1994-10) at 23 °C). For improved handling, the products may be additionally mixed with solvents, which, like alcohols, may also be protic. The solids content of such preparations is preferably > 80 wt% and preferably has a maximum viscosity of 1,000 mPa·s (DIN EN / ISO 3219 (1994-10) at 23 °C).

[0032] The amount of component A) in the composition or coating material according to the invention is preferably 10 to 90 wt.%, particularly preferably 10 to 80 wt.%, in each case based on the total composition or coating material.

[0033] Component B) of the composition or coating according to the invention is a tin-free catalyst. Therefore, the composition or coating according to the invention is preferably entirely tin-free. "Tin-free" within the meaning of the present invention is to be understood as meaning that no tin compound (for example, as a catalyst) is added to the composition or coating according to the invention, but that tin compounds may be introduced into the coating in minute quantities (≤ 0.01 wt.% based on the total composition) as impurities from the previous manufacturing process of the components.

[0034] As tin-free catalysts B), alkylammonium halides or mixtures of different alkylammonium halides are used in the compositions or coating materials according to the invention.

[0035] Alkylammonium halides or mixtures of different alkylammonium halides can also be used as catalysts. The alkyl groups can have 1 to 6 carbon atoms. Preferred alkylammonium halides are alkylammonium fluorides, particularly quaternary alkylammonium fluorides, where the alkyl groups can have 1 to 6 carbon atoms. Tetramethylammonium fluoride (TMAF), tetraethylammonium fluoride (TEAF), tetrapropylammonium fluoride (TPAF), and tetrabutylammonium fluoride (TBAF) can be used as particularly preferred alkylammonium fluorides. The aforementioned alkylammonium fluorides are preferably used in the form of their hydrates, for example, the trihydrate. The alkylammonium halides can be added to the composition, particularly as a solution in a C1 to C6 alcohol, especially methanol, ethanol, propanol, butanol, pentanol, or hexanol.

[0036] The amount of the tin-free catalyst B) in the composition or coating material according to the invention is in particular 0.01 to 3.0 wt.%, preferably 0.1 to 1 wt.%, in each case based on the total composition or the total coating material.

[0037] Component C) of the coating composition according to the invention is an aminosilane. In particular, the aminosilane is an aminoalkylsilane of the general formula (III) A m SiY n (III), wherein A represents a substituted or unsubstituted aminoalkyl group, a substituted or unsubstituted diaminodialkyl group, or a substituted or unsubstituted triaminotrialkyl group; the group Y is, independently of one another, OH, OR', OCOR', OSiR' 3 , Cl, Br, I, or NR' 2 ; m equals 1 or 2; and n equals 1, 2, or 3, with the proviso that m + n = 4; wherein the group R' is in each case independently hydrogen or a linear or branched alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl or heteroaryl group, each having 1 to 18 C atoms and each possibly being substituted.

[0038] Preferably, m equals 1 and n equals 3. Furthermore, Y is preferably selected from OH or OR', with OR' being particularly preferred. In this case, R' is particularly preferably selected from methyl or ethyl groups, with methyl groups being particularly preferred.

[0039] Solche Aminosilane oder Aminoalkylsilane sind beispielsweise, aber nicht ausschließlich, 3-Aminopropyltrimethoxysilan, 3-Aminopropyltriethoxysilan, 2-Aminoethyl-3-aminopropyltrimethoxysilan, 3-Aminopropyl(diethoxymethoxysilan), 3-Aminopropyl(tripropoxysilan), 3-Aminopropyl(dipropoxymethoxysilan), 3-Aminopropyl(tridodecanoxysilan), 3-Aminopropyl(tritetradecanoxysilan), 3-Aminopropyl(trihexadecanoxysilan), 3-Aminopropyl(trioctadecanoxysilan), 3-Aminopropyl(didodecanoxy)tetradecanoxysilan, 3-Aminopropyl(dodecanoxy)-tetradecanoxy(hexadecanoxy)silan, 3-Aminopropyl(dimethoxymethylsilan), 3-Aminopropyl(methoxydimethylsilan), 3-Aminopropyl(hydroxydimethylsilan), 3-Aminopropyl(diethoxymethylsilan), 3-Aminopropyl(ethoxydimethylsilan), 3-Aminopropyl(dipropoxymethylsilan), 3-Aminopropyl(propoxydimethylsilan), 3-Aminopropyl(diisopropoxymethylsilan), 3-Aminopropyl(isopropoxydimethylsilan), 3-Aminopropyl(dibutoxymethylsilan), 3-Aminopropyl(butoxydimethylsilan), 3-Aminopropyl(disiobutoxymethylsilan),3-Aminopropyl(isobutoxydimethylsilan), 3-Aminopropyl(didodecanoxymethylsilan), 3-Aminopropyl(dodecanoxydimethylsilan), 3-Aminopropyl(ditetradecanoxymethylsilan), 3-Aminopropyl(tetradecanoxy-dimethylsilan), 2-Aminoethyl(trimethoxysilan), 2-Aminoethyl(triethoxysilan), 2-Aminoethyl(diethoxymethoxysilan), 2-Aminoethyl(tripropoxysilan), 2-Aminoethyl(dipropoxymethoxysilan), 2-Aminoethyl(tridodecanoxysilan), 2-Aminoethyl(tritetradecanoxysilan), 2-Aminoethyl(trihexadecanoxysilan), 2-Aminoethyl(trioctadecanoxysilan), 2-Aminoethyl(didodecanoxy)tetradecanoxysilan, 2-Aminoethyl(dodecanoxy)tetradecanoxy(hexadecanoxy)silan, 2-Aminoethyl(dimethoxymethylsilan), 2-Aminoethyl(methoxydimethylsilan), 2-Aminoethyl(diethoxymethylsilan), 2-Aminoethyl(ethoxydimethylsilan), 1-Aminomethyl(trimethoxysilan), 1-Aminomethyl(triethoxysilan), 1-Aminomethyl(diethoxymethoxysilan), 1-Aminomethyl(dipropoxymethoxysilan), 1-Aminomethyl(tripropoxysilan), 1-Aminomethyl(trimethoxysilan), 1-Aminomethyl(dimethoxymethylsilan),1-Aminomethyl(methoxydimethylsilan), 1-Aminomethyl(diethoxymethylsilan), 1-Aminomethyl(ethoxydimethylsilan), 3-Aminobutyl(trimethoxysilan), 3-Aminobutyl(triethoxysilan), 3-Aminobutyl(diethoxymethoxysilan), 3-Aminobutyl(tripropoxysilan), 3-Aminobutyl(dipropoxymethoxysilan), 3-Aminobutyl(dimethoxymethylsilan), 3-Aminobutyl(diethoxymethylsilan), 3-Aminobutyl(dimethylmethoxysilan), 3-Aminobutyl(dimethylethoxysilan), 3-Aminobutyl(tridodecanoxysilan), 3-Aminobutyl(tritetradecanoxysilan), 3-Aminobutyl(trihexadecanoxysilan), 3-Aminobutyl(didodecanoxy)tetradecanoxysilan, 3-Aminobutyl(dodecanoxy)tetra-decanoxy(hexadecanoxy)silan, 3-Amino-2-methyl-propyl(trimethoxysilan), 3-Amino-2-methylpropyl(triethoxysilan), 3-Amino-2-methyl-propyl(diethoxymethoxysilan), 3-Amino-2-methylpropyl(tripropoxysilan), 3-Amino-2-methyl-propyl(dipropoxymethoxysilan), 3-Amino-2-methylpropyl(tridodecanoxysilan), 3-Amino-2-methyl-propyl(tritetradecanoxysilan), 3-Amino-2-methyl-propyl(trihexadecanoxysilan),3-Amino-2-methyl-propyl(trioctadecanoxysilan), 3-Amino-2-methyl-propyl(didodecanoxy)tetradecanoxysilan, 3-Amino-2-methylpropyl(dodecanoxy)tetradecanoxy(hexadecanoxy)silan, 3-Amino-2-methylpropyl(dimethoxymethylsilan), 3-Amino-2-methyl-propyl(methoxydimethylsilan), 3-Mercapto-2-methyl-propyl(diethoxymethylsilan), 3-Mercapto-2-methyl-propyl(ethoxydimethylsilan), 3-Mercapto-2-methyl-propyl(dipropoxymethylsilan), 3-Amino-2-methylpropyl(propoxydimethylsilan), 3-Amino-2-methyl-propyl(diisopropoxymethylsilan), 3-Amino-2-methyl-propyl(isopropoxydimethylsilan), 3-Amino-2-methyl-propyl(dibutoxymethylsilan), 3-Amino-2-methyl-propyl(butoxydimethylsilan), 3-Amino-2-methylpropyl(disiobutoxymethylsilan), 3-Amino-2-methyl-propyl(isobutoxydimethylsilan), 3-Amino-2-methyl-propyl(didodecanoxymethylsilan), 3-Amino-2-methyl-propyl(dodecanoxy-dimethylsilan), 3-Amino-2-methyl-propyl(ditetradecanoxymethylsilan) oder 3-Amino-2-methylpropyl (tetradecanoxydimethyl-silan),triaminofunktionelles Propyltrimethoxysilan, Bis(3-trimethoxysilylpropyl)-amin, Bis(3-triethoxysilylpropyl)-amin, N-Benzyl-N-(2-aminoethyl)-3-aminopropyltrimethoxysilan-Hydrochlorid, N-Benzyl-N-(2-aminoethyl)-3-aminopropyltrimethoxysilan-Hydroacetat, N-(n-Butyl)-3-aminopropyltrimethoxysilan, 3-Aminopropylmethyldiethoxysilan, N-Vinylbenzyl-N-(2-aminoethyl)-3-aminopropylpolysiloxan und N-(2-Aminoethyl)-3-aminopropylmethyldimethoxysilan.,

[0040] Preferred aminosilanes or aminoalkylsilanes are substituted or unsubstituted aminosilane compounds, in particular 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 2-aminopropyl-3-aminopropyltrimethoxysilane, 2-aminopropyl-3-aminopropyltriethoxysilane, 2-aminoethyl-2-aminoethyl-3-aminopropyltrimethoxysilane, 2-aminoethyl-2-aminoethyl-3-aminopropyltriethoxysilane and N-(n-butyl)-3-aminopropyltrimethoxysilane. Particularly preferred are 3-Aminopropyltrimethoxysilane (DYNASYLAN® < AMMO), 3-Aminopropyltriethoxysilane (DYNASYLAN® < AMEO), 3-Aminopropylmethyldiethoxysilane (DYNASYLAN® < 1505), N-(n-Butyl)-3-aminopropyltrimethoxysilane (DYNASYLAN® < 1189) and N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (DYNASYLAN® < DAMO), (H3CO)3Si(CH2)3NH(CH2)3Si(OCH3)3 (Bis-AMMO), (H5C2O)3Si(CH2)3NH(CH2)3Si(OC2H5)3 (Bis-AMEO), (H3CO)3Si(CH2)3NH(CH2)2NH(CH2)2NH(CH2)3Si(OCH3)3 (Bis-DAMO), each from the company.Evonik Industries AG, as aminosilanes C).

[0041] The amount of component C) in the composition or coating material according to the invention is 5 to 30 wt.%, preferably 10 to 20 wt.%, in each case based on the total composition or coating material.

[0042] The composition according to the invention can, as mentioned, consist exclusively of components A), B) and C), be free of binders and be used as a coating agent. The coating agent is then a one-component coating agent (1K) consisting of the composition according to the invention.

[0043] The invention relates to a one-component (1K) coating agent comprising at least the composition according to the invention (at least containing or consisting of components A), B) and C)), but no binder. In a preferred embodiment, the 1K coating agent additionally contains at least one auxiliary and / or additive and / or at least one solvent.

[0044] The solvent is preferably an organic solvent, for example ketones, esters, alcohols, or aromatics. The solvent can preferably be present in the 1K coating compound according to the invention in amounts of 1 to 50% by weight, in particular 5 to 75% by weight, in each case based on the total coating compound. The amount of solvent is determined by the desired application viscosity of the coating compound.

[0045] The one-component coating material may contain auxiliary substances and / or additives such as stabilizers, light stabilizers, pigments, fillers, leveling agents, or rheology aids, such as so-called "sag control agents," microgels, or pyrogenic silicon dioxide, but in typical concentrations. In the case of pigment-free coating materials, the auxiliary substances and / or additives may preferably be present in amounts of 0.01 to 90 wt.%, in particular 0.1 to 20 wt.%, in each case based on the total coating material. In the case of coating materials containing pigments and / or fillers, the content of auxiliary substances and / or additives may be 0.01 to 99 wt.%, in particular 0.1 to 90 wt.%, in each case based on the total coating material.

[0046] The coating composition according to the invention can also contain binder components. This results in a two-component (2K) coating composition. The two components (in the present case, the composition of at least A), B) and C) is considered one component and the binder the other component) are stored separately and only mixed together during application, since the binders can only be stored stably with the composition of at least the components A), B) and C) in exceptional cases.

[0047] The invention therefore also relates to a 2K coating agent comprising at least the composition according to the invention, which contains or consists of at least components A), B), and C), and at least one binder component. In a preferred embodiment, the 2K coating agent additionally comprises at least one auxiliary and / or additive and / or at least one solvent.

[0048] In principle, all types of binders known to those skilled in the art are suitable as binder components, including thermoplastic binders, i.e., non-crosslinkable binders, which typically have an average molecular weight > 10,000 g / mol. However, binders with reactive functional groups containing acidic hydrogen atoms are preferred. Suitable binders of this type, for example, have at least one, but preferably two or more, hydroxyl groups. Other suitable functional groups of the binder include, for example, trialkoxysilane functionalities.

[0049] Preferably, polymers containing hydroxyl groups, in particular polyesters, polyethers, polyacrylates, polycarbonates, and polyurethanes containing hydroxyl groups and having an OH number of 20 to 500 mg KOH / g and an average molar mass of 250 to 6000 g / mol, are used as binders with functional groups. Particularly preferred within the scope of the present invention are polyesters or polyacrylates containing hydroxyl groups and having an OH number of 20 to 150 mg KOH / g and an average molecular weight of 500 to 6000 g / mol.

[0050] Resins with a monomer composition such as that described, for example, in DE 195 29124 C1 can be used as hydroxyl-containing (meth)acrylic copolymers. The acid number of the (meth)acrylic copolymer, which can be adjusted by the partial use of (meth)acrylic acid as a monomer, should be 0 to 30, preferably 3 to 15 mg KOH / g. The number-average molecular weight (determined by gel permeation chromatography against a polystyrene standard) of the (meth)acrylic copolymer is preferably 2000 to 20000 g / mol, and the glass transition temperature is preferably -40°C to +60°C. The hydroxyl content of the (meth)acrylic copolymers to be used according to the invention, which can be adjusted by the partial use of hydroxyalkyl(meth)acrylates, is preferably 70 to 250 mg KOH / g, particularly preferably 90 to 190 mg KOH / g.

[0051] Suitable polyester polyols according to the invention are resins with a monomer composition of di- and polycarboxylic acids and di- and polyols, as described in WO 93 / 15849 A1. Polyaddition products of caprolactone to low-molecular-weight di- and triols, such as those available under the name CAPA® (Perstorp), can also be used as polyester polyols. The calculated number-average molecular weight is preferably 500 to 5000 g / mol, particularly preferably 800 to 3000 g / mol; the average functionality is preferably 2.0 to 4.0, more preferably 2.0 to 3.5.

[0052] The urethane- and ester-containing polyols to be used according to the invention are, in principle, those described in EP 0 140 186 A2. Preferably, urethane- and ester-containing polyols produced using HDI, IPDI, trimethylhexamethylene diisocyanate (TMDI), or (H₁₂-MDI) are used. The number-average molecular weight is preferably 500 to 2000 g / mol, and the average functionality is particularly in the range of 2.0 to 3.5.

[0053] Of course, mixtures of the binders described above can also be used. Preferred binders are polyesters containing hydroxyl groups and polyacrylates, alone or in mixtures.

[0054] The proportion of any additional binders in the coating material according to the invention can be, in particular, 5 to 60 wt.%, based on the total coating material, and in particular 10 to 40 wt.%.

[0055] The two-component coating compound according to the invention, including the binder, may additionally contain auxiliary substances and / or additives known in paint technology, such as stabilizers, light stabilizers, pigments, fillers, leveling agents, or rheology aids, such as so-called "sag control agents," microgels, or pyrogenic silicon dioxide, in typical concentrations. If necessary, inorganic or organic color and / or effect pigments commonly used in paint technology may also be incorporated into the coating compound according to the invention.

[0056] In the case of pigment-free coating materials, the auxiliary materials and / or additives may be present in the coating material according to the invention, preferably in amounts of 0.01 to 90 wt.%, in particular 0.1 to 20 wt.%, in each case based on the total coating material. In the case of coating materials containing pigments and / or fillers, the content of auxiliary materials and / or additives may be 0.01 to 99 wt.%, in particular 0.1 to 90 wt.%, in each case based on the total coating material.

[0057] The optional solvent for the two-component coating compound with binder is preferably an organic solvent, for example, ketones, esters, alcohols, or aromatics. The solvent may preferably be present in the coating compound according to the invention in amounts of 1 to 50% by weight, particularly 5 to 75% by weight, based on the total coating compound. The amount of solvent is determined by the desired application viscosity of the coating compound.

[0058] The sum of the proportions of all components of the composition or coating material, i.e. at least components A), B) and C), as well as any additional possible binders, auxiliary and / or additives and solvents, always equals 100 wt.%.

[0059] The compositions or coating materials according to the invention are produced by mixing all the components described above, i.e., at least components A), B) and C). The mixing can be carried out in mixers known to those skilled in the art, for example, stirring vessels, dissolvers, bead mills, roller mills, etc., but also continuously using static mixers.

[0060] Another object of the invention is the use of 1K or 2K coating agents containing at least the composition according to the invention, wherein the coating agents are particularly curable at temperatures from 0 °C to 40 °C, for coating wood, plastic, glass or metal.

[0061] The coatings obtained using the aforementioned coating materials are characterized by high resistance to mechanical stress. Furthermore, they exhibit very good chemical resistance, exceptional weather resistance, and a very good balance between hardness and flexibility.

[0062] Coatings containing the coating materials according to the invention are also the subject of the present invention.

[0063] Even without further explanation, it is assumed that a person skilled in the art can use the above description to the fullest extent. The preferred embodiments and examples are therefore to be understood merely as descriptive disclosures, and in no way as limiting disclosures.

[0064] The present invention will now be explained in more detail using examples. Examples: Example 1): Production of coating materials (1K)

[0065] The individual components are added one after the other to a glass bottle, according to the formulation, and stirred until a homogeneous, well-mixed solution is formed. The alkylammonium halides TMAF and TBAF used were dissolved in ethanol (10% solution of TMAF and TBAF) before being added to the composition. A leveling agent (Tego Glide 410 / 10% in n-butyl acetate) was added to all coating agents. Production of the coatings:

[0066] The compositions prepared as described above are applied to test panels (Chemetall Group / Gardobond 26S 60 OC) using a doctor blade to achieve a wet film thickness of approximately 120 µm. An overview of the prepared compositions can be found in Table 1. All quantities are given as weight percent.

[0067] After application, the coated test panels are stored in a climate-controlled room at 23°C and a relative humidity of 50%. After one day, the pendulum hardness (according to König) is determined on the coated panels. Additionally, the dust drying time is recorded immediately after application of the coating.

[0068] The principle behind pendulum damping is that the amplitude of a supported pendulum decreases more rapidly the stronger the substrate dampens and absorbs the vibrational energy. The sample plate (with coating) is placed on the lifting plate. Using the externally operated lever arm, the lifting plate is then moved towards the pendulum. The pendulum is deflected to the 6° scale position, locked in place with the wire release, and then released. The number of oscillations required for the pendulum to decay from 6° to 3° from the vertical is determined. By multiplying the number of oscillations by a factor of 1.4, the pendulum damping according to König is calculated in seconds. The measurement is performed at two different points within the sample, and the average value is calculated.

[0069] The drying time of the coating material is determined by determining the dust drying time in accordance with EN ISO 9177 (3:2010).

[0070] For this test, the coating substrate is coated with the paint to be tested at the target thickness. The time is recorded. At 10-minute intervals, approximately 0.3 to 0.5 g of glass beads (glass bead diameter: 250-500 µm / manufacturer: Carl-Roth GmbH + Co. KG) are carefully sprinkled onto the coating at a point from a height of 0.5 cm using a small spoon / spatula (diameter of the glass bead pile approximately 1.5 to 2.0 cm). Every 10 minutes, a new, previously uncoated point is treated with glass beads. For fast-curing systems, the interval is reduced to 5 minutes; for slow-curing systems, it is initially increased to 15 to 30 minutes. Towards the end of the curing period, the intervals are then reduced back to 10 minutes. The time elapsed since the coating was applied is recorded for each point.If the paint appears dry, the glass beads are wiped off the metal sheet using a soft brush, and the time is recorded until no glass beads remain on the painted surface. If glass beads are still adhering to the painted surface, the test is continued.

[0071] The results obtained for the produced coatings are shown in Table 2. Table 1: Overview of the manufactured compositions of example 1) A* B* C* D* E* F* G* H I J K VESTANAT EP-M 60 (1) 89,41 89,41 89,41 89,41 89,41 89,41 88,69 88,69 VESTANAT EP-E 95 (2) 89,41 84,50 84,50 Dynasylan AMMO (3) 10,00 10,00 10,00 10,00 10,00 10,00 10,00 10,00 10,00 10,00 10,00 TIB Cat 218 (4) 0,09 0,09 Tego Glide 410 (5) 0,05 0,05 0,05 0,05 0,05 0,05 0,05 0,05 0,05 0,05 0,05 Hordaphos MOB (6) 0,09 Hordaphos MDB (7) 0,09 Polycat DBU (8) 0,09 TMG (9) 0,09 K-KAT XK-678 (10) 0,09 TMAF (11) 0,09 0,5 TBAF*3H 2 O (12) 0,09 0,5 Ethanol 0,72 0,72 4,5 4,5 n-Butyl acetate 0,45 0,45 0,45 0,45 0,45 0,45 0,45 0,45 0,45 0,45 0,45 The compositions marked with * are comparative examples: (1) VESTANAT EP-M 60, adduct of 3-isocyanatopropyltrimethoxysilane and 1,6-hexanediol (ratio of 3-isocyanatopropyltrimethoxysilane to 1,6-hexanediol is 2:1) (2) VESTANAT EP-E 95, adduct of 3-isocyanatopropyltriethoxysilane and 1,6-hexanediol (ratio of 3-isocyanatopropyltriethoxysilane to 1,6-hexanediol is 2:1) (3) Dynasylan AMMO, 3-aminopropyltrimethoxysilane from Evonik Resource Efficiency GmbH (4) TIB Kat 218, dibutyltin dilaurate, TIB Chemicals AG (5) Tego Glide 410, polyether siloxane copolymer, Evonik Resource Efficiency GmbH (6) Hordaphos MOB, Butyl phosphoric ester, Clariant (7) Hordaphos MDB, butyl phosphoric ester, Clariant (8) Polycat DBU, diazabicycloundecene, Evonik Resource Efficiency GmbH (9) Tetramethylguanidine, Merck Millipore (10) K-KAT XK-678, alkyl acid phosphate, King Industries (11) Tetramethylammonium fluoride, Sigma Aldrich (12) Tetrabutylammonium fluoride trihydrate, Sigma Aldrich Table 2: Results for the determination of pendulum hardness and dust drying time Period before measurement Average pendulum hardness A* B* C* D* E* F* G* H I J K 1 day 97 Fluid 115 116 113 116 113 126 139 109 108 Average dust drying time (min.) A* B* C* D* E* F* G* H I J K 35 Fluid 45 45 30 30 30 5 5 5 5

[0072] Table 2 shows that the coating materials containing the tin-free catalysts (samples C to K) harden at room temperature at a comparably fast rate or even faster than the comparison examples with tin-containing catalysts (samples A* and B*). The same applies to the pendulum hardnesses, which are higher in the examples according to the invention. All the catalysts listed according to the invention thus represent an improvement over the known tin-containing catalysts.

[0073] Surprisingly, the use of alkylammonium halides (samples J and K) also made it possible to harden ethoxy-based adducts (2) at room temperature, which was not possible with the known compositions (sample B*).

Claims

1. Composition comprising at least A) an adduct of isocyanatosilanes with hydroxy-functional compounds, B) a tin-free catalyst and C) an aminosilane, wherein the amount of component C) is 5% to 30% by weight, based on the total composition, and the tin-free catalyst B) is an alkylammonium halide.

2. Composition according to Claim 1, wherein the isocyanatosilane is a compound of formula (I)         OCN-(alkyl)-Si(alkoxy)3     (I), in which the alkyl in formula (I) above corresponds to a linear or branched alkyl group having 1 to 4 carbon atoms and the alkoxy in formula (I) above in each case independently corresponds to a methoxy, ethoxy, propoxy or butoxy group, wherein the three alkoxy groups in the compound of formula (I) may in each case be identical or different from one another.

3. Composition according to Claim 2, wherein the alkoxy in the compound of formula (I) is in each case independently selected from methoxy and ethoxy groups.

4. Composition according to Claim 3, wherein the alkoxy groups, in the case that all three alkoxy groups are identical, are not methoxy groups.

5. Composition according to either of Claims 1 and 4, wherein the hydroxy-functional compounds are selected from monoalcohols or polyols, especially diols, triols, tetrols and hydroxyl group-containing polymers.

6. Composition according to any of Claims 1 to 5, wherein the ratio of OH groups of the hydroxy-functional compounds to NCO groups of the isocyanatosilanes is from 0.8: 1 to 1.2: 1.

7. Composition according to any of Claims 1 to 6, wherein the tin-free catalyst B) is an alkylammonium fluoride.

8. Composition according to Claim 7, wherein the tin-free catalyst B) is tetramethylammonium fluoride, tetrapropylammonium fluoride, tetraethylammonium fluoride, tetrabutylammonium fluoride or a mixture thereof.

9. Composition according to any of Claims 1 to 8, wherein the aminosilane is an aminoalkylsilane of the general formula (III)         AmSiYn     (III) in which A is a substituted or unsubstituted aminoalkyl group, a substituted or unsubstituted diaminodialkyl group or a substituted or unsubstituted triaminotrialkyl group; the group Y is in each case independently OH, OR', OCOR', OSiR'3, Cl, Br, I or NR'2; m is 1 or 2; and n is 1, 2 or 3, with the proviso that m + n = 4; wherein the group R' is in each case independently hydrogen or a linear or branched alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl or heteroaryl group, which in each case comprises 1 to 18 carbon atoms and is in each case optionally substituted.

10. 1K or 2K coating composition comprising at least the composition according to any of Claims 1 to 9.

11. 1K or 2K coating composition according to Claim 10, characterized in that it additionally comprises at least one binder component and / or at least one auxiliary and / or additive and / or at least one solvent.

12. 1K or 2K coating composition according to Claim 11, wherein the at least one auxiliary and / or additive is selected from the group consisting of stabilizers, light stabilizers, catalysts, pigments, levelling agents or rheological assistants, such as what are known as "sag control agents", microgels, fumed silicon dioxide, inorganic or organic colour pigments and / or effect pigments or mixtures of two or more thereof.

13. Use of the 1K or 2K coating composition according to any of Claims 10 to 12 for coating wood, plastic, glass or metal.

14. Coating comprising the 1K or 2K coating composition according to any of Claims 10 to 12.