Polyaspartate-based two-component coating compositions for producing coatings having good self-healing properties coupled with low tackiness

Abstract

The present invention relates to two-component coating compositions containing polyaspartic ester and polyether polyol-based polyurethane prepolymers, wherein the proportion of polyols, polyether polyols and polyether polyamines and the proportion of components having a functionality > 2 in the coating composition (excluding auxiliaries, additives and solvents) are in a defined range, to a process for producing these compositions, to the use thereof for producing coatings and to the use of these coatings as a protective coating, in particular for objects that are subjected to (repeated) mechanical stresses.

Description

[0001] Polyaspartate-based two-component coating compositions for the production of coatings with good self-healing properties and low tackiness

[0002] The present invention relates to two-component coating compositions containing polyaspartic acid esters and polyether polyol-based polyurethane prepolymers, wherein the proportion of polyols, polyether polyols and polyether polyamines, as well as the proportion of components with a functionality > 2 in the coating composition (excluding auxiliaries, additives and solvents) are within a defined range, a process for producing these compositions, their use for producing coatings, and the use of these coatings as a protective coating, in particular for objects exposed to (repeated) mechanical stresses.

[0003] Two-component (2K) coatings, which contain a polyisocyanate component as a binder in combination with a reactive component reactive toward isocyanate groups, particularly a polyhydroxyl component, have long been known. They are suitable for the production of high-quality coatings that can be made hard, elastic, abrasion- and solvent-resistant, and, above all, weather-resistant.

[0004] Within this 2K polyurethane coating technology, certain secondary polyamines containing ester groups have recently become established. In combination with lacquer polyisocyanates, they are particularly suitable as binders in low-solvent or solvent-free (high solids) coating materials and enable rapid curing of the coatings at low temperatures. These secondary polyamines are the so-called polyaspartic acid esters, as described, for example, in EP0403921. Their use alone or in a mixture with other components reactive toward isocyanate groups in 2K coating materials is described, for example, in EP0403921, EP0639628, EP0667362, EP0689881, US5214086, EP0699696, EP0596360, EP0893458, DE19701835, and US5243012.

[0005] Surfaces of objects exposed to repeated mechanical stress benefit from their ability to self-heal. This can reduce fatigue damage. In the case of impact loads, the impact energy must be absorbed without material failure. The material must be elastic, not brittle. Elastic materials are characterized by high elongation at break. At the same time, a low glass transition temperature is helpful so that the materials do not become brittle and remain elastic even at high impact speeds (time-temperature superposition principle). One application where materials that can withstand repeated impact loads at high impact speeds are advantageous is leading edge protection for wind turbine rotor blades.

[0006] Materials with self-healing properties can have the disadvantage of stickiness. This is particularly undesirable in coatings, as particles of all kinds (e.g., dust or sand) adhere to the coating. This can result in disadvantages in the respective applications, such as higher air resistance or undesirable haptics.

[0007] Coatings that exhibit good self-healing properties and low stickiness are particularly desirable.

[0008] The present invention reports for the first time self-healing properties of coating compositions containing polyaspartic acid esters.

[0009] The object of the present invention was to provide coatings with good self-healing capabilities combined with low tackiness. Adequate self-healing capabilities are defined for the purposes of the present invention as an elongation at break of > 40% after 24 hours of self-healing (i.e., storage at 23°C, 50% relative humidity). It is known that tack increases with decreasing modulus of a material (CA Dahlquist, "Adhesion - Fundamentals and Practice - A Report of an International Conference held at the University of Nottingham, England, September 20-22, 1966", Maclaren and Sonst Ltd, London). A storage modulus at 23°C and 1 Hz of > 0.7 MPa (determined by dynamic mechanical analysis) is considered low tackiness for the purposes of the invention.A further object of the invention was to provide coatings with elongation at break in the undamaged state of > 100% and a glass transition temperature (determined via maximum tangent delta at 1 Hz) < 23 °C.

[0010] This task was solved by the two-component coating compositions described below, containing polyaspartic acid esters and polyether polyol-based polyurethane prepolymers, wherein the proportion of polyols, polyether polyols and polyether polyamines, as well as the proportion of components with a functionality > 2 in the coating composition (excluding auxiliaries, additives and solvents) are within a defined range.

[0011] WO 2004 / 033517 A1, WO 2020 / 016292 A1, and WO 2020 / 094689 A1 describe coating compositions based on polyaspartic acid esters and polyether polyol-based polyurethane prepolymers. WO 2004 / 033517 A1 and WO 2020 / 016292 A1 essentially use propylene oxide- and / or ethylene oxide-based polyether polyols, while WO 2020 / 094689 also describes the use of other polyether polyols, such as trimethylene oxide-based polyether polyols. However, none of these documents discloses coating compositions in which both the proportion of polyols, polyether polyols, and polyether polyamines, as well as the proportion of components with a functionality > 2, are within the ranges defined in claim 1, much less the effect obtainable by this combination of features.

[0012] WO 2020 / 260578 A1 also discloses an aspartate-based coating composition (coating 6) in the examples section, which contains a polyether-based allophanate prepolymer as a hardener. Despite the fact that the hardener is not a urethane prepolymer, the proportion of components with a functionality > 2 in the coating composition is significantly too high. The coating does not have sufficient self-healing properties, as can be seen from Example 35 of the experimental section of the present documents.

[0013] The present invention relates to two-component coating compositions (2K coating agents) containing

[0014] A) at least one polyaspartic acid ester-containing component which contains one or more polyaspartic acid esters of the general formula (I)

[0015] (I), in which m is an integer >1, preferably 2,

[0016] X represents an m-valent organic radical optionally containing one or more heteroatoms, as can be obtained by removing the primary amino groups from a cycloaliphatic, linearaliphatic or araliphatic bonded polyamine or polyetheramine having primary amino groups and a molecular weight range of 60 to 6000 g / mol, and which may contain further functional groups that are reactive towards isocyanate groups and / or inert at temperatures up to 100°C, and the radicals R1 and R2 represent identical or different organic radicals each having 1 to 18 carbon atoms, and optionally one or more polyaspartic acid esters of the general formula (II)

[0017] ° (II), in which n is m-1, and X and the radicals RI and R2 have the meaning given above, contains or consists of and is obtainable by reacting

[0018] Al) at least one polyamine or polyetherpolyamine of the general formula (III),

[0019] (III), in which m and X have the meaning given above, with

[0020] A2) at least one compound of the general formula (IV)

[0021] (IV), in which RI and R2 have the meaning given above,

[0022] B) at least one NCO-functional polyurethane prepolymer which is obtainable by reacting

[0023] Bl) at least one polyisocyanate with

[0024] B2) at least one polyether polyol having linear ether groups and / or branched ether groups of the following general formulas (V) to (VII):

[0025] — O — (CFE — (V), where x = 2 to 10, preferably 2 to 6, particularly preferably 2 to 4, — O — CR 3 R 4 — CH2— (VI) , where R 3 and R 4are independent of one another and represent hydrogen or an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, which may also contain oxygen atoms, or an aromatic radical having up to 10 carbon atoms, but at least one of the radicals R 3 or R 4 is not hydrogen, and

[0026] — O — CR 5 R 6 — CR 7 R 8 — (VII), where R 5 to R 8 are independent of each other and where R 5 and R 7 represents hydrogen or an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, which may also contain oxygen atoms, and R 6 and R 8 represents an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, which may also contain oxygen atoms, or R 6and R 8 are linked together in such a way that a saturated or unsaturated ring with up to 8 carbon atoms is formed, which may be substituted by organic radicals, B3) optionally at least one polyol different from B2,

[0027] C) optionally one or more components other than A which are reactive towards isocyanate groups,

[0028] D) optionally one or more isocyanate components different from B, selected from the group comprising D1) modified polyisocyanates obtainable from the reaction of monomeric polyisocyanates with polyols and D2) isocyanate components different from D1,

[0029] E) - El) where appropriate, auxiliary and / or additive substances, excluding those of components E2 and E3,

[0030] - E2) optionally inorganic fillers and / or inorganic pigments and / or

[0031] - E3 optionally solvent, where Gx is defined as the total amount of

[0032] - polyetherpolyamines of formula III incorporated into the polyaspartic acid esters of the polyaspartic acid ester-containing component A,

[0033] - polyether polyols B2 and polyols B3 incorporated in the polyurethane prepolymers B,

[0034] - polyols and polyetherpolyamines falling under component C, and

[0035] - polyols incorporated in the modified polyisocyanates D1, based on the total weight of components A to E1, and GF is defined as the total amount of components A to D which have a functionality > 2, based on 1 kg of components A to E1, where the functionality comprises the isocyanate groups and isocyanate-reactive groups, and where: i) if component B2 contains < 100 to > 70% by weight of linear ether groups and > 0 to <

[0036] 30% by weight of branched ether groups, based on the total amount of linear and branched ether groups of component B2, then G x > 35 to < 72 wt% and GF > 0 to < 0.09 mol / kg, and ii) if component B2 contains > 0 to < 70 wt% linear ether groups and < 100 to >

[0037] 30% by weight of branched ether groups, based in each case on the total amount of linear and branched ether groups of component B2, and iii) GF is > 0 to < 0.05 mol / kg, then Gx is > 35 to < 50% by weight, or

[0038] Ü2) If GF is > 0.05 to < 0.09 mol / kg, then Gx is> 35 to < 65 weight percent.

[0039] With regard to the above-mentioned embodiment i), the following preferred ranges apply: Gx is preferably > 35 to < 72 percent by weight and GF > 0 to < 0.08 mol / kg, preferably > 0 to < 0.05 mol / kg.

[0040] Particularly preferably, Gx is > 40 to < 68 weight percent and GF > 0 to < 0.09 mol / kg, preferably > 0 to < 0.08 mol / kg, particularly preferably > 0 to < 0.05 mol / kg.

[0041] Most preferably, Gx is > 50 to < 65 weight percent and GF is > 0 to < 0.09 mol / kg, preferably > 0 to < 0.08 mol / kg, particularly preferably > 0 to < 0.05 mol / kg.

[0042] With regard to the embodiment Ü2) specified above, the following preferred ranges apply: GF is preferably > 0.05 to < 0.08 mol / kg and Gx > 35 to < 65 weight percent.

[0043] In the context of the present invention, the term “linear” means “unbranched” and the term “linearaliphatic” means “open-chain aliphatic”.

[0044] Linear ether groups are therefore unbranched ether groups, such as those containing n-propylene units. In contrast, there are branched ether groups, such as those containing isopropylene units. Aliphatic linear residues are thus aliphatic unbranched residues, such as n-propylene residues. In contrast, there are aliphatic branched residues, such as isopropylene residues.

[0045] Open-chain aliphatic residues are referred to as linear aliphatic. These can be branched or unbranched.

[0046] The present invention also relates to two-component coating compositions (2K coating agents) consisting of components A to E.

[0047] The amount of polyether polyols B2 and polyols B3 incorporated in the polyurethane prepolymers B, or polyols incorporated in the modified polyisocyanates Dl, shall be determined as follows:

[0048] If components B or Dl are monomer-free linear compounds, i.e. monomer-free compounds based on unbranched polyether polyols or polyols, according to Flory (PJ Flory, “Molecular Size Distribution in Linear Condensation Polymers”, JACS 1936, pp. 1877-1885). If components B or Dl are monomer-free branched compounds, i.e. monomer-free compounds based on branched polyether polyols or polyols, by simulation according to WO 2021 / 055398 A1. The determination for non-monomer-free compounds is carried out by calculation from the respective recipe of the manufacturing instruction. The content of polyether polyols and polyetheramines based on the total weight of components A1 to E1 of the coating composition can also be determined experimentally via quantitative deuterated digestion with 'H NMR analysis. For this purpose, approx. 100 mg of sample are used together with approx.20 mg of the internal standard naphthalene are weighed into a test tube. 2 mL of deuterated sodium hydroxide solution in deuterated methanol are used as the digestion reagent. The test tube is then sealed and placed in a heating cabinet at 150 °C overnight. The following day, a portion of the solution is transferred to an NMR tube and measured by 'H-NMR (400 MHz, 256 scans). For the quantitative evaluation of the measurement, the building blocks specific to the respective polyether are integrated and used to calculate the content. Attention must be paid to the corresponding proton ratio and to the fact that these are building blocks or repeating units of the polyether.

[0049] The amount of polyetherpolyamines of formula III incorporated into the polyaspartic acid esters of the polyaspartic acid ester-containing component A is calculated from the recipe of the manufacturing procedure (Example: PAE-D230 described in RSC Adv., 2018, 8, 13474, is prepared from 115 g of polyetheramine Jeffamine D230 and 172.18 g of diethyl maleate. Consequently, the product contains 40% polyetheramine.) If secondary components are removed, for example by distillation, this is also taken into account.

[0050] Component A containing polyaspartic acid ester

[0051] The at least one polyaspartic acid ester-containing component A preferably contains one or more polyaspartic acid esters of the general formulas (I) and optionally (II) in which R1 and R2 represent identical or different alkyl radicals each having 1 to 18 carbon atoms, preferably identical or different alkyl radicals each having 1 to 8 carbon atoms, and very particularly preferably each represent alkyl radicals such as methyl, ethyl, propyl, isopropyl, butyl, or isobutyl radicals. Ethyl is most preferred.

[0052] The at least one polyaspartic acid ester-containing component A contains one or more polyaspartic acid esters of the general formulas (I) and optionally (II), in which X represents organic radicals obtained by removing the primary amino groups from a corresponding polyamine or polyetheramine having (cyclo)aliphatic or araliphatic bonded primary amino groups, selected from the following group: all known polyamines or polyetheramines having primary amino groups which correspond to the general formula (III).Examples of polyamines include the following compounds: ethylenediamine, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 2,5-diamino-2,5-dimethylhexane, 1,5-diamino-2-methylpentane (Dytek®A, DuPont), 1,6-diaminohexane, 2,2,4- and / or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane or triaminononane, aliphatic polycyclic polyamines such as tricyclodecanebismethylamine (TCD diamine) or bis(aminomethyl)norbornane, amino-functional siloxanes, e.g. diaminopropylsiloxane G10 DAS (Momentive), fatty alkyl-based amines such as fentamine from Solvay, Dimer fatty acid diamines such as Priamine from Croda. Examples of polyether polyamines include: 4,9-dioxadodecane-l,12-diamine, 4,7,10-trioxatridecane-l,13-diamine, as well as higher molecular weight polyether polyamines with aliphatically bonded primary amino groups, such as those sold by Huntsman under the name Jeffamin®.

[0053] Preferably, the at least one polyaspartic acid ester-containing component A contains one or more polyaspartic acid esters of the general formulas (I) and optionally (II) in which X represents organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III) in which m = 2 and X represents a cyclic hydrocarbon radical having at least one cyclic carbon ring. Examples of particularly preferably used diamines are l-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (IPDA), 2,4- and / or 2,6-hexahydrotoluenediamine (H6-TDA), isopropyl-2,4-diaminocyclohexane, and / or isopropyl-2,6-diaminocyclohexane, 1,3-bis-(aminomethyl)-cyclohexane, 2,4'- and / or 4,4'-diamino-dicyclohexylmethane, 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane (Laromin® C 260, Fa.BASF AG), the isomeric diaminodicyclohexylmethanes (=C-monomethyldiaminodicyclohexylmethanes) containing a methyl group as a core substituent, 3(4)-aminomethyl-l-methylcyclohexylamine (AMCA) as well as araliphatic diamines, such as l,3-bis(aminomethyl)benzene or m-xylylenediamine.

[0054] Likewise preferably, the at least one polyaspartic acid ester-containing component A contains one or more polyaspartic acid esters of the general formulas (I) and optionally (II) in which X represents organic radicals obtained by removing the primary amino groups from one of the polyamines or polyetherpolyamines of the general formula (III) selected from the group: polyetherpolyamines with aliphatically bound primary amino groups, 1,2-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and / or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminododecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and / or 2,6-hexahydrotoluenediamine, 1,5-diaminopentane, 2,4'- and / or 4,4'-diaminodicyclohexylmethane or 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane.Particularly preferred are 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane, 1,5-diaminopentane, 2,4'- and / or 4,4'-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane and very particularly preferred is the use of 2,4'- and / or 4,4'-diaminodicyclohexylmethane.Particularly preferably, the at least one polyaspartic acid ester-containing component A contains one or more polyaspartic acid esters of the general formulas (I) and optionally (II), in which X represents organic radicals obtained by removing the primary amino groups from one of the polyamines or polyetherpolyamines of the general formula (III), selected from the group: polyetherpolyamines with aliphatically bound primary amino groups, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and / or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminododecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and / or 2,6-hexahydrotoluenediamine, 2,4'- and / or 4,4'-diaminodicyclohexylmethane or 3,3'-dimethyl-4,4'diaminodicyclohexylmethane.

[0055] Most preferably, the at least one polyaspartic acid ester-containing component A contains one or more polyaspartic acid esters of the general formulas (I) and optionally (II), in which X represents organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III), selected from the group: 3,3'-dimethyl-4,4'diaminodicyclohexylmethane, 2,4'- and / or 4,4'-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane.

[0056] The index m stands for an integer >1 and preferably for 2.

[0057] If the at least one polyaspartic acid ester-containing component A contains one or more polyaspartic acid esters of the general formula (II), this / these is / are present in a proportion of > 0%, preferably at least 0.1% (> 0.1%), particularly preferably at least 1% (> 1%), very particularly preferably at least 4% (> 4%), and preferably of a maximum of 20% (< 20%), particularly preferably a maximum of 15% (< 15%) of the GC surface area (measured as area % in the gas chromatogram), where the sum of the GC surface areas of the compounds of the two general formulae (I) and (II) is 100%. The stated upper and lower limits can be combined as desired. All possible combinations are deemed to be disclosed.

[0058] Preferably, the at least one polyaspartic acid ester-containing component A contains one or more polyaspartic acid esters of the general formula (I) and optionally formula (II), wherein the esters have a platinum-cobalt color number < 200, particularly preferably < 100. The platinum-cobalt color number is measured in accordance with DIN EN ISO 6271:2016-05.

[0059] The polyaspartic acid ester-containing components A to be used according to the invention can be prepared by the following process:

[0060] Reaction of polyamines or polyetherpolyamines of the general formula (III), m

[0061] (III), where X is an m-valent organic radical optionally containing one or more heteroatoms, as can be obtained by removing the primary amino groups from a (cyclo)aliphatically or araliphatically bound polyamine or polyetherpolyamine having primary amino groups and having a molecular weight range of > 60 to < 6000 g / mol, and which may contain further functional groups which are reactive towards isocyanate groups and / or inert at temperatures up to 100°C, and m is an integer > 1, preferably 2, with compounds of the general formula (IV)

[0062] R 1 OOC— CH— CH — COOR 2 (iy)where R1 and R2 are identical or different organic radicals, preferably identical or different alkyl radicals each having 1 to 18 carbon atoms, particularly preferably identical or different alkyl radicals each having 1 to 8 carbon atoms, very particularly preferably alkyl radicals such as methyl, ethyl, propyl, isopropyl, butyl or isobutyl radicals and most preferably ethyl, and distillative removal of the excess portion of the compound of the general formula (IV).

[0063] In the first step, the compounds of the general formula (III) and (IV) are reacted at temperatures between 0°C and 100°C, preferably 20° to 80°C and particularly preferably 20° to 60°C, in a ratio of the equivalents of the primary amino groups of the compounds of the general formula (III) to the C=C double bond equivalents of the compounds of the general formula (IV) of 1: 1.2 to 1.2: 1, but preferably 1: 1.05 to 1.05: 1, particularly preferably 1: 1, up to a residual content of compounds of the general formula (IV) of 2 to 15% by weight, preferably 3 to 10% by weight.

[0064] Polyaspartic acid ester-containing components A which contain only polyaspartic acid esters of the general formula (I) but not of the formula (II), or which are almost free of polyaspartic acid esters of the general formula (II), can be prepared analogously, but with an excess of compounds of the general formula (IV), ie in a ratio of the equivalents of the primary amino groups of the compounds of the general formula (III) to the C=C double bond equivalents of the compounds of the general formula (IV) of 1:10, preferably 1:5, particularly preferably 1:2.

[0065] The reaction is followed by a distillation step in which the excess compounds of the general formula (IV) are removed.

[0066] Suitable conditions during distillation are a pressure range between 0.01 and 2 mbar and a temperature of the bottom effluent at the outlet from the distillation apparatus < 170°C and > the temperature resulting from the following formula (VIII):

[0067] T(bottom effluent) = 27 x ln(p) + 150 (VIII) where T(bottom effluent) is the temperature of the bottom effluent in °C and p is the pressure in the distillation apparatus in mbar.

[0068] Maintaining this pressure range ensures that, on the one hand, moderate temperatures in the bottom effluent are sufficient to deplete the compounds of general formula (IV) to the desired extent, while, on the other hand, the process remains applicable on an industrial scale. At lower pressures, the gas density becomes too low, and the required equipment becomes so large that the process becomes economically disadvantageous.

[0069] Preferably, the temperature of the bottom effluent is < 170°C, but at least 20 K above the temperature resulting from formula (VIII), particularly preferably it is between 20 K and 40 K above the temperature resulting from formula (VIII) but not above 170°C.

[0070] During the production of polyaspartic acid esters based on maleic acid esters as compounds of formula (IV), a retro-Michael addition can occur as an undesirable side reaction, in which the corresponding fumaric acid dialkyl esters are formed by elimination of the polyamine as a minor component. These dialkyl fumarates have a sensitizing effect. They are among the compounds of formula (IV) and are removed in the distillation step, or their content is significantly reduced by distillation.

[0071] If the polyaspartic acid ester-containing component A contains fumaric acid dialkyl esters, these are present in amounts of > 0% to < 3 wt.%, preferably > 0.01 to < 1.5 wt.%, more preferably > 0.01 to < 1 wt.%, most preferably > 0.01 to < 0.5 wt.%, based on the total weight of component A.

[0072] With regard to examples and preferred ranges of the polyamines of the general formula (III) which can be used in the process described above, reference is made to the preceding statements.

[0073] Preferred compounds of general formula (IV) used in the process described above are maleic or fumaric acid esters of general formula (IV), wherein R1 and R2 are identical or different organic radicals each having 1 to 18 carbon atoms. R2 is preferably 1 and R 2independently of one another represent linear or branched alkyl radicals having 1 to 8 carbon atoms, particularly preferably alkyl radicals such as methyl, ethyl, propyl, isopropyl, butyl, or isobutyl radicals, and very particularly preferably ethyl. Examples of compounds of the general formula (IV) include the following compounds: dimethyl, diethyl, di-n- or isopropyl, di-n-butyl, di-2-ethylhexyl, or the corresponding fumaric esters. Diethyl maleate is very particularly preferred.

[0074] Component B

[0075] The two-component coating compositions according to the invention contain as component B at least one NCO-functional polyurethane prepolymer, which is obtainable by reacting

[0076] Bl) at least one polyisocyanate with

[0077] B2) at least one polyether polyol, and

[0078] B3) optionally at least one polyol different from B2.

[0079] Polyisocyanates B1 suitable for the production of NCO-functional polyurethane prepolymers preferably have a functionality > 2.

[0080] Suitable polyisocyanates B1 for the preparation of the NCO-functional polyurethane prepolymers include, for example, monomeric polyisocyanates. These include any monomeric diisocyanates that are accessible via phosgenation in the liquid or gas phase or by a phosgene-free route. Preferred diisocyanates are those in the molecular weight range of 140 to 400 g / mol with linear-aliphatic, cycloaliphatic, araliphatic, and / or aromatic isocyanate groups, such as 1,4-diisocyanatobutane, 1,5-diisocyanatopentane (pentamethylene diisocyanate, PDI), 1,6-diisocyanatohexane (hexamethylene diisocyanate, 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, l-Isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (Isophorone diisocyanate, IPDI), 4,4'-Diisocyanatodicyclohexylmethane, 1-Isocyanato-l-methyl-4(3)isocyanatomethylcyclohexane, Bis-(isocyanatomethyl)norbornane, 1,3- and 1,4-Bis(isocyanatomethyl)benzene (Xylylene diisocyanate, XDI), 1,3- and l,4-Bis-(2-isocyanato-prop-2-yl)-benzene (Tetramethylxylylene diisocyanate, TMXDI), 2,4- and 2,6-Diisocyanatotoluene (toluene diisocyanate, TDI), 2,4'- and 4,4'-diisocyanatodiphenylmethane (MDI), 1,5-diisocyanatonaphthalene, or mixtures of at least two such diisocyanates. Triisocyanatononane (TIN) is an example of a monomeric polyisocyanate with an NCO functionality of > 2.

[0081] Particularly preferred diisocyanates are those in the molecular weight range of 140 to 400 g / mol with linear-aliphatic, cycloaliphatic, and / or araliphatic isocyanate groups, most preferably with linear-aliphatic and / or cycloaliphatic isocyanate groups. Furthermore, preferably with linear-aliphatic isocyanate groups. Most preferred are PDI and / or HDI.

[0082] Other suitable polyisocyanates B1 for the preparation of NCO-functional polyurethane prepolymers are linear aliphatic, cycloaliphatic, araliphatic, and aromatic polyisocyanates with an NCO functionality of > 2 and uretdione, isocyanurate, allophanate, urea, biuret, iminooxadiazinedione, and / or oxadiazinetrione structures (hereinafter also referred to as modified polyisocyanates). These can be obtained from monomeric polyisocyanates with an NCO functionality of > 2 of the type described above. Their synthesis is 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 as well as 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 and JP 56059828 are described by way of example.

[0083] In the preparation of these modified polyisocyanates B1, the actual modification reaction with uretdione, isocyanurate, allophanate, urea, biuret, iminooxadiazinedione, and / or oxadiazinetrione structures is generally followed by a further process step for separating the unreacted excess monomeric isocyanates. This monomer separation is carried out by conventional methods, preferably by thin-film distillation under high vacuum or by extraction with suitable solvents inert toward isocyanate groups, for example aliphatic or cycloaliphatic hydrocarbons such as pentane, hexane, heptane, cyclopentane, or cyclohexane. The modified polyisocyanates thus obtainable preferably have a monomeric isocyanate content of less than 0.5% by weight, particularly preferably less than 0.3% by weight. The residual monomer contents are measured according to DIN EN ISO 10283:2007-11 using gas chromatography with an internal standard.

[0084] Preferred modified polyisocyanates B1 are those with an NCO functionality of > 2 and uretdione, isocyanurate, allophanate, urea, biuret, iminooxadiazinedione, and / or oxadiazinetrione structures with exclusively linear-aliphatic and / or cycloaliphatic isocyanate groups. Particular preference is given to polyisocyanates with an NCO functionality of > 2 and an isocyanurate and / or allophanate structure that contain exclusively linear-aliphatic and / or cycloaliphatic isocyanate groups, preferably those based on PDI, HDI, IPDI, and / or 4,4'-diisocyanatodicyclohexylmethane. Most preferred are polyisocyanates with an NCO functionality of > 2 and an isocyanurate and / or allophanate structure that contain exclusively linear-aliphatic isocyanate groups, preferably those based on PDI, HDI.

[0085] In principle, the use of mixtures of different polyisocyanates of the type mentioned above is of course also possible.

[0086] The polyether polyols B2 suitable for producing the NCO-functional polyurethane prepolymers preferably have number-average molecular weights Mn of > 200 to < 10,000 g / mol, particularly preferably > 400 to < 2,500 g / mol and an average hydroxyl functionality of preferably > 1.8 to < 6, particularly preferably > 1.9 to < 2.1 g / mol, very particularly preferably > 1.9 to < 2 g / mol.

[0087] Suitable polyether polyols B2 have linear ether groups and / or branched ether groups of the following general formulas (V) to (VII): i) — O — (CH2) X — (V), where x is 2 to 10, preferably 2 to 6, particularly preferably 2 to 4. ii) — O — CR 3 R 4 — CH2 — (VI) , where R 3 and R 4are independent of one another and represent hydrogen or an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, which may also contain oxygen atoms, or an aromatic radical having up to 10 carbon atoms, but at least one of the radicals R 3 or R 4 is not hydrogen. R 3 and R 4 independently of one another and represent hydrogen or an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, but at least one of the radicals R 3 or R 4 is not hydrogen.

[0088] Particularly preferred is R 3 for hydrogen and R 4 represents an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, preferably 6 carbon atoms. iii) — O — CR 5 R 6 — CR 7 R8 — (VII), where R 5 to R 8 are independent of each other and where R 5 and R 7 represents hydrogen or an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, which may also contain oxygen atoms, and R 6 and R 8 represents an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, which may also contain oxygen atoms, or R 6 and R 8 are linked together in such a way that a saturated or unsaturated ring with up to 8 carbon atoms is formed, which may be substituted with organic radicals.

[0089] Preferred are R 5 to R 8 independent of each other and are R 5 and R 7 for hydrogen and R 6 and R 8for an aliphatic linear or branched, saturated or unsaturated radical having up to 10 carbon atoms, preferably 6 carbon atoms.

[0090] Suitable polyether polyols B2 are obtainable, for example, by ring-opening polymerization of cyclic ethers in the presence of hydroxy-functional compounds.

[0091] Suitable hydroxy-functional compounds are preferably water or those which have an OH functionality of > 2 to < 6, for example propylene glycol, 1,3-propanediol, ethylene glycol, diethylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, hexanediol, pentanediol, 3-methyl-1,5-pentanediol, 1,12-dodecanediol, glycerol, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol, sucrose, hydroquinone, pyrocatechol, resorcinol, bisphenol F, bisphenol A, 1,3,5-trihydroxybenzene or methylol group-containing condensates of formaldehyde and phenol. These can also be used in mixtures. The polyols are preferably selected from the group consisting of propylene glycol, 1,3-propanediol, glycerol, trimethylolpropane and pentaerythritol.

[0092] The following compounds are suitable as cyclic ethers for the production of polyether polyols B2: ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, 2-methyl-1,2-propylene oxide (isobutylene oxide), 1,2-pentylene oxide, 2,3-pentylene oxide, 2-methyl-1,2-butylene oxide, 3-methyl-1,2-butylene oxide, 1,2-hexylene oxide, 2,3-hexylene oxide, 3,4-hexylene oxide, 2-methyl-1,2-pentylene oxide, 4-methyl-1,2-pentylene oxide, 2-ethyl-1,2-butylene oxide, 1,2-heptylene oxide, 1,2-octylene oxide, 1,2-nonylene oxide, 1,2-decylene oxide, 1,2-Undecylene oxide, 1,2-Dodecylene oxide, 4-methyl-1,2-pentylene oxide, butadiene monoxide, isoprene monoxide, cyclopentene oxide, cyclohexene oxide, cycloheptene oxide, cyclooctene oxide, styrene oxide, methylstyrene oxide, pinene oxide, derivatives of glycidol, such as methyl glycidyl ether, ethyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, trimethylene oxide, tetramethylene oxide (THF), pentamethylene oxide, hexamethylene oxide, heptamethylene oxide, decamethylene oxide.Several of these ethers can also be copolymerized.

[0093] The polyether polyols B2 are preferably based on ethylene oxide, propylene oxide and / or tetramethylene oxide (THF), particularly preferably on propylene oxide and / or tetramethylene oxide (THF).

[0094] The synthesis of polyether polyols of the above-mentioned type is described in detail, for example, in DE 26 22 951 B, column 6, line 65 to column 7, line 26; EP-A 0 978 523, page 4, line 45 to page 5, line 14; and WO 2011 / 069966, page 4, line 20 to page 5, line 23. Syntheses are known in which the ring-opening polymerization is acid-catalyzed, for example, for the preparation of poly-THF. Detailed explanations can be found, for example, in Angew. Chem. 72, 927 (1960).

[0095] For the production of NCO-functional polyurethane prepolymers, other polyols (B3) different from B2 can be used.

[0096] These can be, for example, low-molecular-weight polyols with a molecular weight range of 62 to 300 g / mol, for example ethylene glycol, propylene glycol, trimethylolpropane, glycerol, or mixtures of these alcohols, or polyhydroxy compounds with a molecular weight above 300 g / mol, preferably above 400 g / mol, particularly preferably between 400 and 20,000 g / mol. Such polyhydroxy compounds are, in particular, those that have 2 to 6, preferably 2 to 3, hydroxyl groups per molecule and are selected from the group consisting of polyester, polythioether, polyurethane, polycarbonate, and polyacrylate polyols.

[0097] To produce the NCO-functional polyurethane prepolymers, the polyisocyanate(s) B1 and the polyether polyol(s) B2 and, if appropriate, the polyol(s) B3 are reacted to form urethane, maintaining an NCO / OH equivalent ratio of 1.5:1 to 20:1. The reaction takes place at temperatures of 20 to 200°C, preferably 40 to 140°C, particularly preferably 50 to 120°C. When using an excess of polyisocyanate of more than 2:1, excess monomeric polyisocyanate is preferably removed after the reaction by distillative or extractive processes (e.g., thin-film distillation).

[0098] The reaction can be accelerated by using a catalyst that accelerates urethane formation. Common catalysts include, for example, organotin compounds, bismuth compounds, zinc compounds, titanium compounds, zirconium compounds, or amine catalysts. If one or more catalysts are used, preferably 0.001 to 5 wt. %, in particular 0.002 to 2 wt. % of catalyst or catalyst combination, based on the total weight of the prepolymer batch, is used.

[0099] The reaction can be carried out using a solvent or solvent mixture. Common solvents include those described below under "Auxiliaries and Additives (Component E)" for the preparation of the two-component coating composition according to the invention. Reference is made to the list therein.

[0100] The proportion of polyether polyols B2 is at least 30 percent by weight, preferably at least 40 percent by weight, particularly preferably at least 60 percent by weight, based on the total weight of component B.

[0101] The polyurethane prepolymers preferably have an average NCO functionality of > 1.8, preferably from > 2 to < 2.3.

[0102] Components C

[0103] In addition to the polyaspartic acid ester-containing component A, the two-component composition according to the invention may contain further components reactive towards isocyanate groups.

[0104] These can be, for example, low molecular weight polyols in the molecular weight range from 62 to 300 g / mol, for example ethylene glycol, propylene glycol, trimethylolpropane or glycerol.

[0105] Polyols with a molecular weight above 300 g / mol, preferably above 400 g / mol, and particularly preferably between 400 and 20,000 g / mol may also be used. Such polyols are, in particular, those having 2 to 6, preferably 2 to 3, hydroxyl groups per molecule and selected from the group consisting of polyester, polyether, polythioether, polyurethane, polycarbonate, and polyacrylate polyols. Other suitable compounds reactive toward isocyanate groups include, for example, polyamines or polyetherpolyamines. Particularly suitable polyamines are those having at least two primary amino groups per molecule and optionally also secondary amino groups, and preferably having an average molecular weight of 60 to 500.Suitable examples are ethylenediamine, 1,2- and 1,3-diaminopropane, 1,4-diaminobutane, 2,2,4- and / or 2,4,4-trimethylhexamethylenediamine, the isomeric xylenediamines, 1,4-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 1,3-diaminocyclopentane, 4,4'-diaminodicyclohexylsulfone, 4,4'-diaminodicyclohexylpropane-1,3, 4,4'-diaminodicyclohexylpropane-2,2, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3-aminomethyl-3,3,5-trimethylcyclohexylamine.

[0106] (Isophoronediamine), 3(4)-aminomethyl-1-methylcyclohexylamine, technical-grade bisaminomethyltricyclodecane, octahydro-4,7-methanoindene-1,5-dimethanamine, or polyamines that contain secondary amino groups in addition to at least two primary amino groups, such as diethylenetriamine or triethylenetetramine. Particularly suitable polyether polyamines are polyether polyamines with aliphatically bonded primary amino groups, such as those sold by Huntsman under the trade name Jeffamin®.

[0107] Isocyanate components D

[0108] Monomeric polyisocyanates (component D2), for example, are suitable as isocyanate component D (different from B). For a description of suitable monomeric polyisocyanates, please refer to the information on monomeric polyisocyanates under component B1. These, including the preferred ranges mentioned there, apply analogously here.

[0109] Also suitable as isocyanate component D are modified polyisocyanates, i.e., linear aliphatic, cycloaliphatic, araliphatic, and aromatic polyisocyanates with an NCO functionality of > 2 and uretdione, isocyanurate, urethane, allophanate, urea, biuret, iminooxadiazinedione, and / or oxadiazinetrione structures. These can be obtained from monomeric polyisocyanates with an NCO functionality of > 2 of the type described above. Polyisocyanates modified with urethane and / or allophanate structures are based on the reaction of the monomeric polyisocyanates, preferably with polyester, polythioether, polyurethane, polycarbonate, and / or polyacrylate polyols, and are included in component D1). Modified polyisocyanates that do not have urethane and / or allophanate structures are included in component D2).

[0110] Regarding the synthesis and processing of the modified polyisocyanates, reference is made to the information under component B1. These apply analogously here. Preferred modified polyisocyanates are those with an NCO functionality of > 2 and uretdione, isocyanurate, urethane, allophanate, urea, biuret, iminooxadiazinedione, and / or oxadiazinetrione structures with exclusively linear-aliphatic and / or cycloaliphatic isocyanate groups. Particular preference is given to polyisocyanates with an NCO functionality of > 2 and an isocyanurate, urethane, and / or allophanate structure that contain exclusively linear-aliphatic and / or cycloaliphatic isocyanate groups, preferably those based on PDI, HDI, IPDI, and / or 4,4'-diisocyanatodicyclohexylmethane.Most preferred are polyisocyanates with an NCO functionality > 2 having an isocyanurate, urethane and / or allophanate structure which have exclusively linear-aliphatic bonded isocyanate groups, preferably those based on PDI, HDI.

[0111] Components El and E2

[0112] Component E1 includes, for example, organic pigments, fillers, or fibers, such as indigo, PTFE particles, or Kevlar fibers. Inorganic pigments and fillers, such as titanium dioxide, zinc oxide, iron oxides, chromium oxides, carbon black, barite, chalk, wollastonite, or talc, are included in component E2. A detailed overview of pigments and fillers for coatings can be found in "Textbook of Paints and Coatings, Volume II, Pigments, Fillers, Dyes," by H. Kittel, published by W.A. Colomb in Heenemann GmbH, Berlin-Oberschwandorf, 1974, pp. 17-265.

[0113] The auxiliaries and additives El also include catalysts / activators such as titanium, zirconium, bismuth, tin, and / or iron-containing catalysts, as described, for example, in WO 05058996. The addition of amines or amidines is also possible.

[0114] Examples of other suitable auxiliaries and additives E1 include coating additives, such as light stabilizers such as UV absorbers and sterically hindered amines (HALS), as well as stabilizers, defoamers, anti-crater and / or wetting agents, leveling agents, film-forming aids, reactive diluents, biocides, solvents, or substances for rheology control. The use of light stabilizers, in particular UV absorbers such as substituted benzotriazoles, S-phenyltriazines, or oxalanilides, as well as sterically hindered amines, particularly those with 2,2,6,6-tetramethylpiperidyl structures—referred to as HALS—is described by way of example in A. Valet, Lichtschutzmittel für Lacke (Light Stabilizers for Paints), Vincentz Verlag, Hanover, 1996.

[0115] Stabilizers such as radical scavengers and other polymerization inhibitors such as sterically hindered phenols stabilize coating components during storage and are intended to prevent discoloration during curing. Wetting and leveling agents improve surface wetting and / or the leveling of coatings. Examples include fluorosurfactants, silicone surfactants, and special polyacrylates. Rheology-controlling additives are important for controlling the properties of the two-component system during application and during the leveling phase on the substrate and are known, for example, from patents WO 9422968, EP0276501, EP0249201, and WO 9712945. Water scavengers such as triethyl orthoformate, toluene sulfoisocyanate, monooxazolidines, or molecular sieves, and hydrolysis inhibitors such as carbodiimides, can also be used.A detailed overview of paint additives can be found in the “Textbook of Paints and Coatings, Volume III, Solvents, Plasticizers, Additives, Intermediates”, H. Kittel, Verlag WA Colomb in der Heenemann GmbH, Berlin-Oberschwandorf, 1976, pp. 237-398.

[0116] Solvent (component E3)

[0117] The solvent can be an organic solvent or a mixture of organic solvents. Suitable solvents are to be used in the Bachmann manner, tailored to the composition and application method. Solvents should dissolve the components used, promote their mixing and avoid incompatibilities. Furthermore, they should leave the coating during application and curing in a manner that is tailored to the ongoing crosslinking reaction, so that a solvent-free coating is created with the best possible appearance and without defects such as popping or pinholes. Solvents that are used in two-component technology are particularly suitable. Examples of organic solvents are ketones such as acetone, methyl ethyl ketone or hexanone, esters such as ethyl acetate, butyl acetate, methoxypropyl acetate, substituted glycols and other ethers, aromatics such as xylene or solvent naphtha such as those from the company.Exxon Chemicals, as well as mixtures of the solvents mentioned. If the NCO-reactive part of the composition is present as an aqueous dispersion, water is also suitable as a solvent or diluent.

[0118] The ratio of the molar amounts of the isocyanate groups from B and D and the NCO-reactive groups from A and C in the coating composition is preferably from 0.5 to 1.0 to 3.0 to 1.0. A ratio of 0.9 to 1.0 to 1.5 to 1.0 is particularly preferred. A ratio of 0.99 to 1.0 to 1.2 to 1.0 is most preferred.

[0119] If components C which are different from A and are reactive towards isocyanate groups are contained in the coating composition, their proportion is a maximum of 75 percent by weight, preferably a maximum of 50 percent by weight, based on the total weight of components A to E2.

[0120] If isocyanate components D different from B are present in the coating composition, their proportion is a maximum of 50 percent by weight, preferably a maximum of 30 percent by weight, based on the total weight of components A to E2. If auxiliaries and / or additives (component E1) and / or inorganic fillers and / or inorganic pigments (component E2) are present in the coating composition, their proportion is a maximum of 60 percent by weight, preferably a maximum of 25 percent by weight, particularly preferably a maximum of 10 percent by weight, based on the total weight of components A to E2.

[0121] If solvents (component E3) are contained in the coating agent, their proportion is a maximum of 50 percent by weight, preferably a maximum of 25 percent by weight, based on the total weight of components A to E3.

[0122] The two-component compositions according to the invention are preferably not foamable or foam-forming compositions. The compositions are preferably not radically polymerizable, in particular not photopolymerizable, ie, the compositions do not cure by radical processes, in particular not by radical polymerization processes initiated by actinic radiation.

[0123] The two-component coating compositions according to the invention are produced according to methods known per se in coating technology.

[0124] An isocyanate-reactive component (R) and an isocyanate-containing component (H) are first prepared separately by mixing the respective isocyanate-reactive components A and C, or by mixing the respective polyisocyanate components B and D. The auxiliaries and additives E are preferably added to the isocyanate-reactive component R. The components R and H thus prepared are only mixed immediately before or during application. If mixing occurs before application, it should be noted that the reaction between the components already begins after mixing. Depending on the selection of components and additives, the reaction will proceed at different rates.The processing time within which the composition must be applied, also known as the pot life and defined as the time from mixing the components until the flow time doubles, ranges from 1 minute to 24 hours, depending on the selected components, but usually from 10 minutes to 8 hours. Pot life is determined using methods known to those skilled in the art.

[0125] The invention also relates to a method for producing a coating on a substrate, which comprises at least the following steps: i) applying a two-component coating composition described above to at least a part of a substrate to be coated, and ii) curing the coating composition from step i).

[0126] The substrates may already be fully or partially coated with one or more coating layers. These coating layers may still be uncured or wet, partially cured or fully cured; preferably, the subsequent coating layers on the substrate are partially cured or fully cured. Examples of coating layers include primers, fillers, putties, basecoats, or already fully coated substrates that are recoated after any pretreatment such as sanding or plasma activation.

[0127] The two-component coating compositions are used primarily for the production of protective coatings, especially for objects exposed to (repeated) mechanical stress, such as rotor blades of wind turbines or helicopters, aircraft wings, and ship propellers. The entire surface of such a component can be coated. It is also possible to coat only certain surface areas of the component, such as the leading edge of a rotor blade, an aircraft wing, or a ship propeller.

[0128] Further preferred objects of the present invention are therefore the use of the two-component coating compositions described above for producing coatings on substrates, the process described above for coating substrates with these coatings, and the coated substrates themselves thus obtainable.

[0129] The coating composition can be applied using conventional application methods. Examples of application methods include brushing and rolling, roller application, doctor blade coating, dipping, and spraying. After an optional flash-off period, the composition according to the invention is cured or dried on the substrate or object. This occurs using methods customary in coating technology, either under ambient conditions with regard to temperature and humidity or under forced conditions, for example, by increasing the temperature in ovens, using radiation such as infrared, near-infrared, or microwave radiation, as well as using dehumidified and / or heated air or other gases. It is preferable to avoid the use of forced curing equipment.The applied coating composition is cured, for example, at temperatures from -20 to 100°C, preferably from -10 to 80°C, more preferably from 0 to 60°C, and most preferably from 10 to 40°C. Although not preferred, lower curing temperatures may also be used, but will result in longer curing times. It is also possible, although not preferred, to cure the composition at higher temperatures, for example, 80 to 160°C or higher. After the first coating layer has cured, a further coating layer may be applied and also cured.

[0130] The coating compositions according to the invention lead to coatings which are characterized by the following features:

[0131] - an elongation at break > 40% after 24 hours of self-healing (i.e. storage at 23°C, 50% relative humidity), preferably > 60%, particularly preferably > 90%,

[0132] - an elongation at break in the undamaged state (before self-healing test) > 100%, preferably > 300%, particularly preferably > 500% and - a glass transition temperature (determined via maximum tangent delta at 1 Hz)

[0133] < 23 °C, preferably < 0 °C, particularly preferably < -10 °C; if a coating has several glass transition temperatures, at least one of them must meet this condition.

[0134] - a storage modulus at 23 °C and 1 Hz > 0.7 MPa, preferably > 0.8 MPa.

[0135] Experimental part

[0136] Methods

[0137] Unless otherwise indicated, all percentages are based on weight.

[0138] Unless otherwise stated, the viscosity was determined at a temperature of

[0139] 23 °C and a shear rate of 50 / s according to DIN 53019.

[0140] The NCO contents were determined volumetrically according to DIN-EN ISO 11909.

[0141] The residual diisocyanate content or residual monomer content was determined according to DIN EN ISO 10283.

[0142] Tensile stress and elongation at break were determined according to DIN 53504:2017-03. The specimens were previously stored for 24 hours at 23 °C and 50% relative humidity. To test self-healing, the tensile bars were placed on a flat surface and cut in the middle, transverse to the tensile direction, with a razor blade (Martor, Solingen). The cut surfaces were then rejoined with light hand pressure for 3 seconds. The specimens were then

[0143] Stored for 24 hours at 23 °C and 50% relative humidity, and breaking stress and elongation at break were determined again according to DIN 53504:2017-03.

[0144] Dynamic mechanical analysis was performed on a Mettler DMA SDTA 861 in shear mode. Two 6 mm diameter cylinders were placed in a double shear test holder. The maximum force amplitude was 0.5 N and the maximum strain was 2 μm. The measurements were performed in the temperature range from -100 °C to +150 °C with a heating rate of 1 K / min and test frequencies of 1, 10, 100, and 500 Hz.

[0145] The polyether polyol contents of the monomer-free linear prepolymers 1-10 were calculated according to Flory (PJ Flory, "Molecular Size Distribution in Linear Condensation Polymers", JACS 1936, pp. 1877-1885). The polyether polyol contents of non-distilled prepolymers (prepolymer 11) are easily calculated using the respective formulation. The polyether polyol contents of monomer-free branched prepolymers (e.g., Desmodur E30600) were calculated using simulation according to WO 2021 / 055398 Al.

[0146] The calculation of Gx is based on the prepolymer proportions and the previously determined polyether polyol contents of the prepolymers. If the aspartate component A or component C or D contains polyethers, these are also taken into account. The ability of a coating composition to form dense networks is described by GF.

[0147] Calculation example for G x based on coating compound 16

[0148] According to Table 1, coating compound 16 contains 63.42 g of prepolymer 7, 13.02 g of Desmodur N 3600 and 43.55 g of Desmophen NH 1420. The total mass is 119.99 g.

[0149] The formulation of Prepolymer 7 contains 1680 g of HDI and 1000 g of the polyether Desmophen 1110 BD. Thus, the polyether content of the prepolymer before distillation is 37.3%. According to the Schulz-Flory distribution, 50.8% of the mixture is unreacted monomeric HDI. After distillative removal of the excess monomeric HDI, the polyether content increases to 75.8%.

[0150] 75.8% of 63.42 g of prepolymer 7 corresponds to 48.07 g of polyether. Since Desmodur N 3600 and Desmophen NH 1420 do not contain polyether, the percentage of polyether based on the total mass of components AD 100 x 48.07 / 119.99 = 40%. G x is therefore 40%.

[0151] Calculation example for GF based on coating compound 16

[0152] According to Table 1, coating compound 16 contains 63.42 g of prepolymer 7, 13.02 g of Desmodur N 3600 and 43.55 g of Desmophen NH 1420. The total mass is 119.99 g.

[0153] Prepolymer 7 and Desmophen NH 1420 have a functionality of 2. Desmodur N 3600 has a functionality of > 2 and a number-average molecular weight (Mn) of 710 g / mol. 13.02 g of Desmodur N 3600 corresponds to a molar amount of 0.018 mol per 119.99 g. Based on 1 kg of components AD, this is 0.15 mol. The GF is therefore 0.15 mol / kg.

[0154] Substances and abbreviations used

[0155] HDI: Hexamethylene diisocyanate (Desmodur® H, Covestro Deutschland AG)

[0156] Poly(tetrahydrofuran): Products with number-average molecular weights of 250, 1000, 1400, and 2000 g / mol were purchased from BASF. Poly(tetrahydrofuran) with a number-average molecular weight of 650 g / mol was provided by Merck.

[0157] Desmodur® N 3600: Product of Covestro Deutschland AG, isocyanurate trimer of HDI, functionality > 2, NCO content 23%, average molecular weight of 710 g / mol (determined by GPC).

[0158] Desmodur® E30600: Product of Covestro Deutschland AG, HDI prepolymer based on polypropylene glycol with a functionality > 2, a polyol content of 75.6% and an average molecular weight of 2755 g / mol (determined by GPC).

[0159] Desmophen® 1262 BD: Product of Covestro Deutschland AG, difunctional polypropylene glycol with an average molar mass of 431.5 g / mol (OH number 260 mgKOH / g)

[0160] Desmophen® 1110 BD: Product of Covestro Deutschland AG, difunctional polypropylene glycol with an average molar mass of 1000 g / mol (OH number 112 mgKOH / g). Desmophen® 2060 BD: Product of Covestro Deutschland AG, difunctional polypropylene glycol with an average molar mass of 2000 g / mol (OH number 56 mgKOH / g).

[0161] Ecoprol® 1000H: Product of SK Chemicals, difunctional poly(l,3-propanediol) with an average molar mass of 1000 g / mol (OH number 112 mgKOH / g)

[0162] Desmophen® NH 1420: Product of Covestro Deutschland AG, difunctional amine with an equivalent weight of 276 g / mol, contains no polyether groups.

[0163] Prepolymer 1

[0164] 1680 g of HDI were initially charged, heated to 80 °C, and 250 g of poly(tetrahydrofuran) with an average molecular weight of 250 g / mol (OH number 450 mg KOH / g) were added dropwise over 60 minutes with stirring. Stirring was continued at 80 °C for 120 minutes until an NCO content of 38.6% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.08 mbar. A prepolymer was obtained that solidified into a white solid upon cooling to room temperature. The following properties were obtained:

[0165] NCO content: 13.4%

[0166] Residual monomer content: 0.08%

[0167] Viscosity at 50 °C: 185 mPas

[0168] Polyether polyol content (calculated): 43.9%

[0169] Functionality: 2

[0170] Prepolymer 2

[0171] 1680 g of HDI were initially charged, heated to 80 °C, and 650 g of poly(tetrahydrofuran) with an average molecular weight of 650 g / mol (OH number 173 mgKOH / g) were added dropwise over 60 minutes while stirring. Stirring was continued at 80 °C for 190 minutes until an NCO content of 32.2% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.04 mbar. A liquid prepolymer with the following properties was obtained:

[0172] NCO content: 7.6%

[0173] Residual monomer content: 0.04%

[0174] Viscosity: 1610 mPas

[0175] Polyether polyol content (calculated): 67.0%

[0176] Functionality: 2 Prepolymer 3

[0177] 2520 g of HDI were initially charged, heated to 80 °C, and 1500 g of poly(tetrahydrofuran) with an average molecular weight of 1000 g / mol (OH number 112 mgKOH / g) were added dropwise over 60 minutes while stirring. Stirring was continued at 80 °C for 75 minutes until an NCO content of 27.9% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.04 mbar. Initially, a liquid prepolymer was obtained, which slowly solidified into a white solid over several days. The following properties were measured:

[0178] NCO content: 5.7%

[0179] Residual monomer content: 0.04%

[0180] Viscosity: 2200 mPas

[0181] Polyether polyol content (calculated): 75.8%

[0182] Functionality: 2

[0183] Prepolymer 4

[0184] 840 g of HDI were initially charged, heated to 80 °C, and 700 g of poly(tetrahydrofuran) with an average molecular weight of 1400 g / mol (OH number 80 mgKOH / g) were added dropwise over 60 minutes while stirring. Stirring was continued at 80 °C for 120 minutes until an NCO content of 24.3% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.04 mbar. Initially, a liquid prepolymer was obtained, which slowly solidified into a white solid over several days. The following properties were measured:

[0185] NCO content: 4.4%

[0186] Residual monomer content: 0.03%

[0187] Viscosity: 4780 mPas

[0188] Polyether polyol content (calculated): 81.4%

[0189] Functionality: 2

[0190] Prepolymer 5

[0191] 630 g of HDI were initially charged, heated to 80 °C, and 750 g of poly(tetrahydrofuran) with an average molecular weight of 2000 g / mol (OH number 56 mgKOH / g) were added dropwise over 105 minutes while stirring. Stirring was continued at 80 °C for 250 minutes until an NCO content of 20.5% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.1 mbar. Initially, a liquid prepolymer was obtained, which solidified overnight into a white solid. The following properties were measured: NCO content: 3.2%

[0192] Residual monomer content: 0.02%

[0193] Viscosity at 40 °C: 2630 mPas

[0194] Polyether polyol content (calculated): 86.2%

[0195] Functionality: 2

[0196] Prepolymer 6a

[0197] 1680 g of HDI were initially charged, heated to 80 °C, and 431.5 g of Desmophen 1262 BD with an average molecular weight of 431.5 g / mol (OH number 260 mg KOH / g) were added dropwise over 60 minutes with stirring. Stirring was continued at 80 °C for 75 minutes until an NCO content of 35.7% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.3 mbar. A liquid prepolymer was obtained.

[0198] NCO content: 10.3%

[0199] Residual monomer content: 0.13%

[0200] Viscosity: 1730 mPas

[0201] Polyether polyol content (calculated): 57.5%

[0202] Functionality: 2

[0203] Prepolymer 6b

[0204] 2520 g of HDI were initially charged, heated to 80 °C, and 647.3 g of Desmophen 1262 BD with an average molecular weight of 431.5 g / mol (OH number 260 mg KOH / g) were added dropwise over 60 minutes with stirring. Stirring was continued at 80 °C for 780 minutes until an NCO content of 35.8% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.4 mbar. A liquid prepolymer was obtained.

[0205] NCO content: 10.5%

[0206] Residual monomer content: 0.78%

[0207] Viscosity: 1610 mPas

[0208] Polyether polyol content (calculated): 57.0%

[0209] Functionality: 2

[0210] Prepolymer 7

[0211] 1680 g of HDI were initially charged, heated to 80 °C, and 1000 g of Desmophen 1110 BD with an average molecular weight of 1000 g / mol (OH number 112 mg KOH / g) were added dropwise over 90 minutes with stirring. Stirring was continued at 80 °C for 260 minutes until an NCO content of 28.0% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.08 mbar. A liquid prepolymer was obtained.

[0212] NCO content: 5.9%

[0213] Residual monomer content: 0.04%

[0214] Viscosity: 1500 mPas

[0215] Polyether polyol content (calculated): 75.8%

[0216] Functionality: 2

[0217] Prepolymer 8

[0218] 840 g of HDI were initially charged, heated to 80 °C, and 1000 g of Desmophen 2060 BD with an average molecular weight of 2000 g / mol (OH number 56 mg KOH / g) were added dropwise over 90 minutes with stirring. Stirring was continued at 80 °C for 600 minutes until an NCO content of 20.5% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.04 mbar. A liquid prepolymer was obtained.

[0219] NCO content: 3.3%

[0220] Residual monomer content: 0.03%

[0221] Viscosity: 1530 mPas

[0222] Polyether polyol content (calculated): 86.2%

[0223] Functionality: 2

[0224] Prepolymer 9

[0225] 1680 g of HDI were initially charged, heated to 80 °C, and 1000 g of Ecoprol HI 000 with an average molecular weight of 2000 g / mol (OH number 56 mgKOH / g) were added dropwise over 120 minutes with stirring. Stirring was continued at 80 °C for 150 minutes until an NCO content of 28.0% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.08 mbar. A liquid prepolymer was obtained.

[0226] NCO content: 5.8%

[0227] Residual monomer content: 0.07%

[0228] Viscosity: 1670 mPas

[0229] Polyether polyol content (calculated): 75.8%

[0230] Functionality: 2 Prepolymer 10

[0231] 840 g of HDI were initially charged, heated to 80 °C, and 1000 g of Ecoprol H2000 with an average molecular weight of 2000 g / mol (OH number 56 mgKOH / g) were added dropwise over 60 minutes with stirring. Stirring was continued at 80 °C for 284 minutes until an NCO content of 20.5% was reached. The excess HDI was removed in a two-stage short-path evaporator (pre-evaporator 130 °C, main evaporator 120 °C) under a vacuum of 0.04 mbar. A liquid prepolymer was obtained.

[0232] NCO content: 3.3%

[0233] Residual monomer content: 0.07%

[0234] Viscosity: 4520 mPas Polyether polyol content (calculated): 86.2%

[0235] Functionality: 2

[0236] Prepolymer 11

[0237] Synthesis according to US20040067315, Example 3. NCO content: 1.8%

[0238] Viscosity: 13900 mPas

[0239] Polyether polyol content (calculated): 90.0%

[0240] Concentration of components with F > 2: 0.045 mol / kg

[0241] Table 1: Production of coating materials

[0242] Continuation of Table 1:

[0243] Continuation of Table 1:

[0244] Continuation of Table 1:

[0245] Continuation of Table 1:

[0246] Continuation of Table 1:

[0247] Continuation of Table 1:

[0248] According to the recipes in Table 1, the prepolymer was initially charged and Desmophen® NH 1420 was added. The mixture was then homogenized for 1 min in the Speedmixer DAC 150 Z.

[0249] Example 35

[0250] Coating compound according to W02020 / 260578 Al coating 6.

[0251] Example 36 Pigmented coating compositions were prepared according to the recipes in Table 2. For this purpose, the A component was prepared in a dissolver (Dispermat VMA-Gerztman) and, after adding the isocyanate prepolymer (B component), mixed for 1 minute in a speed mixer (Hausschild DAC 150 FVZ).

[0252] Table 2: Production of pigmented coating materials

[0253] Film production

[0254] The coating compounds from Examples 1-36 were poured into molds. Approximately 5 mm thick films were produced for self-healing tests and approximately 3 mm thick films for dynamic mechanical analysis. The films were cured for at least 14 days at room temperature.

[0255] Table 3 provides an overview of the film properties. Rain erosion test

[0256] 45 cm long U-shaped NACA 63-021 test substrates simulating the leading edge of a wind turbine rotor blade (as described in Appendix A1, DNGVL-RP-0171) were first coated with a thin layer of adhesion primer. Subsequently, 400 μm of the coating compositions in Example 36 (Table 2) were applied. The coating cured for at least 14 days at room temperature.

[0257] A regeneration test was conducted according to DNVGL-RP 0171 with a rotor speed of 1000 rpm, a water flow rate of 65 L / h, a rainfall intensity of 31.34 mm / h, an average droplet size of 2511 mm, and a test chamber temperature between 14 and 23 °C. The inspection interval was 15 minutes. The coating showed no erosion damage even after 20 hours of testing.

[0258] Table 3: Film properties of the films produced from coating compositions 1-35

[0259]

[0260] * No tensile test possible because the material does not show self-healing.

[0261] ** In addition to a broad glass transition around -19.2 °C, this coating shows a melting point with an onset of melting at approximately 30 °C.

[0262] *** Coating shows two glass transition temperatures.

[0263] **** Example 35 corresponds to coating 6 of W02020 / 260578 Al and is based on a polyether allophanate prepolymer and a polyether aspartate.

[0264] 5 The polyetherpolyamine content of the aspartate was taken into account when calculating Gx.

[0265] Table 3 shows the film properties of the films produced from coating compositions 1-35. Examples 1-9 and 36 show coatings containing poly(tetrahydrofuran). Adequate self-healing properties are only observed at poly(tetrahydrofuran) contents between 35 and 72%. For example 36, a rain erosion resistance of at least 20 hours was also demonstrated. Examples 7 to 9 were produced at various NCO:NH ratios of 0.95, 1.05, and 1.15 and demonstrate that the task can be achieved with different NCO:NH ratios. Examples 10-22 and 32-35 show coatings containing poly(propylene glycol). Analogous to poly(tetrahydrofuran), coatings with poly(propylene glycol) contents below 35% do not show self-healing (see Examples 10 and 22).In contrast to poly(tetrahydrofuran), coatings with poly(propylene glycol) can exhibit self-healing properties even at very high poly(propylene glycol) contents (see Examples 17, 32, 33), but these exhibit high tackiness. Example 32 was prepared according to US20040067315 Table 1 Entry 9. The increased tackiness is demonstrated by the very low storage moduli. Weakly cross-linked coatings (GF = 0 to < 0.05 mol / kg) become too tacky at a poly(propylene glycol) content of 50% or more, i.e., the storage modulus is 0.7 or less. This can be partially compensated by cross-linking (see Examples 15 and 19 with GF > 0.05). However, with too much cross-linking, the self-healing properties are lost again (see Examples 16, 20, 21, 34, 35). Example 35 was carried out according to WO20260578 Coating 6. Examples 23 to 31 show coatings containing poly(l,3-propanediol).Analogous to the coating compositions with poly(tetrahydrofuran), coating compositions with poly(l,3-propanediol) show self-healing properties in the range Gx > 35% to < 72% and GF < 0.09 mol / kg.

Claims

The present invention relates to two-component coating compositions comprising A) at least one component containing polyaspartic acid esters, which includes one or more polyaspartic acid esters of the general formula (I) (I), in which m represents an integer >1, preferably 2, X represents an m-valent organic residue, optionally containing one or more heteroatoms, such as can be obtained by removing the primary amino groups from a polyamine or polyetheramine with cycloaliphatic, linearaliphatic or araliphatic primary amino group bonded in the molecular weight range of 60 to 6000 g / mol, and which may contain further functional groups that are reactive towards isocyanate groups and / or inert at temperatures up to 100°C, and the residues RI and R2 represent identical or different organic residues, each with 1 to 18 carbon atoms, and optionally one or more polyaspartic acid esters of the general formula (II) (II), in which n stands for m-1, and X and the residues RI and R2 have the meaning above, contains or consists of and is obtainable by implementation Al) at least one polyamine or polyether polyamine of general formula (III), (III), in which m and X have the meanings given above, with A2) at least one compound of the general formula (IV) H 1ÜOC CII AI I COOH2 (IV), in which RI and R2 have the meanings given above, B) at least one NCO-fictional polyurethane prepolymer obtainable by implementation Bl) at least one polyisocyanate with B2) at least one polyether polyol with linear ether groups and / or branched ether groups of the following general formulas (V) to (VII): — O — (CH2)x — (V), where x = 2 to 10, — O — CR 3 R 4 — CH2— (VI) , where R 3 and R 4are independent of each other and represent hydrogen or an aliphatic linear or branched, saturated or unsaturated residue with up to 10 carbon atoms, which may also contain oxygen atoms, or an aromatic residue with up to 10 carbon atoms, wherein at least one of the residues R 3 or R 4 It is not hydrogen, and — O — CR 5 R 6 — CR 7 R 8 — (VII), where R 5 to R 8 are independent of each other and where R 5 and R 7 for hydrogen or an aliphatic linear or branched, saturated or unsaturated residue with up to 10 carbon atoms, which may also contain oxygen atoms, and R 6 and R 8 for an aliphatic linear or branched, saturated or unsaturated residue with up to 10 carbon atoms, which may also contain oxygen atoms, or R 6 and R 8are linked together in such a way that a saturated or unsaturated ring with up to 8 carbon atoms is formed, which may be substituted with organic residues, B3) possibly at least one polyol different from B2, C) optionally one or more components other than A that are reactive towards isocyanate groups, D) optionally one or more isocyanate components other than B, D selected from the group comprising D1) modified polyisocyanates obtainable from the reaction of monomeric polyisocyanates with polyols and D2) further isocyanate components other than D1, E) - El) if applicable, auxiliary and / or additive substances, excluding those of components E2 and E3, - E2) possibly inorganic fillers and / or inorganic pigments and / or - E3 possibly solvent, wherein G x is defined as the total amount of - polyether polyamines of formula III incorporated into the polyaspartic acid esters of the polyaspartic acid ester-containing component A, - the polyether polyols B2 and polyols B3 incorporated into the polyurethane prepolymers B, - Polyols and polyether polyamines falling under component C, and - incorporated polyols in the modified polyisocyanates D 1, based on the total weight of components A to El, and GF is defined as the total amount of components A to D exhibiting a functionality > 2, based on 1 kg of components A to El, where the functionality includes the isocyanate groups and isocyanate-reactive groups, and where: i) if component B2 comprises < 100 to > 70 wt% linear ether groups and > 0 to < 30 wt% branched ether groups, respectively, based on the total amount of linear and branched ether groups of component B2, then G shall be x> 35 to < 72 wt% and GF > 0 to < 0.09 mol / kg, and ii) if component B2 comprises > 0 to < 70 wt% linear ether groups and < 100 to > 30 wt% branched ether groups, in each case based on the total amount of linear and branched ether groups of component B2, and iii) GF > 0 to < 0.05 mol / kg, then Gx > 35 to < 50 wt%, or Ü2) GF > 0.05 to < 0.09 mol / kg, then Gx > 35 to < 65 wt%.

2. Two-component coating compositions according to claim 1, wherein: Component B2 comprises < 100 to > 70 weight percent linear ether groups and > 0 to < 30 weight percent branched ether groups, respectively, based on the total amount of linear and branched ether groups of component B2, and G x is > 35 to < 72 Weight percent and GF is > 0 to < 0.09 mol / kg.

3. Two-component coating compositions according to claim 1, wherein for embodiment i) applies, or according to claim 2, wherein: Gx is > 35 to < 72 percent by weight and GF is > 0 to < 0.08 mol / kg, preferably > 0 to < 0.05 mol / kg.

4. Two-component coating compositions according to claim 1, wherein for embodiment i) applies, or according to claim 2, wherein: Gx is > 40 to < 68 percent by weight and GF is > 0 to < 0.09 mol / kg, preferably > 0 to < 0.08 mol / kg, particularly preferably > 0 to < 0.05 mol / kg. Two-component coating compositions according to claim 1, wherein for embodiment Ü2) the following applies: GF is > 0.05 to < 0.08 mol / kg and Gx is > 35 to < 65 wt%. Two-component coating compositions according to any one of claims 1 to 5, wherein the at least one polyisocyanate Bl is selected from the group comprising: monomeric diisocyanates of the molecular weight range 140 to 400 g / mol with linear aliphatic, cycloaliphatic, araliphatic and / or aromatically bonded isocyanate groups and polyisocyanates of an NCO functionality > 2 with uretdione, isocyanurate, allophanate, urea, biuret, iminooxadiazindione and / or oxadiazinetrione structures with linear aliphatic, cycloaliphatic, araliphatic and / or aromatically bonded isocyanate groups. Two-component coating compositions according to any one of claims 1 to 5, wherein the at least one polyisocyanate B 1 is selected from monomeric diisocyanates of the molecular weight range 140 to 400 g / mol with exclusively linearaliphatic and / or cycloaliphatic bonded isocyanate groups.Two-component coating compositions according to any one of claims 1 to 7, wherein x in formula (V) represents 2 to 6, preferably 2 to 4. Two-component coating compositions according to any one of claims 1 to 8, wherein for formula (VI) R. 3 stands for hydrogen and R 4 for an aliphatic linear or branched, saturated or unsaturated residue with up to 10 carbon atoms. Two-component coating compositions according to any one of claims 1 to 8, wherein for formula (VI) the following applies: R 3 stands for hydrogen and R 4 for an aliphatic linear or branched saturated residue with up to 6 carbon atoms, preferably for a methyl residue. A method for producing a coating on a substrate, comprising at least the following steps: i) applying a two-component coating composition according to any one of claims 1 to 10 to at least a portion of a substrate to be coated, and ii) curing the coating composition from step i). Substrates coated with a coating, obtainable according to a method according to claim 11. A method for producing a coating on a substrate according to claim 11, or substrates coated with a coating according to claim 12, characterized in that the coating is a protective coating for objects subjected to mechanical stress.A method for producing a coating on a substrate according to claim 11 or 13, or substrates coated with a coating according to claim 12 or 13, characterized in that the coating is for rotor blades of wind turbines or helicopters, for aircraft wings or ship propellers. Use of a two-component coating composition according to any one of claims 1 to 10 for producing coatings on substrates.

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