HK1249761B - Improved coating systems, use thereof for coating components and thus coated components for wind power plants - Google Patents

Description

Improved coating system, use thereof for coating components and components coated thereby for wind turbines

The present invention relates to improved coating materials based on RMA systems crosslinked by means of classical Michael addition, coatings producible therefrom, and coated components, in particular components for wind turbines, such as machine housings or rotor blades.

Coating materials that crosslink using the Michael addition reaction are known. The coatings produced therefrom have high weathering stability and chemical resistance. The rapid curing of these coating materials is achieved by using high catalyst contents, but this results in a significantly shortened processing time and pot life of the coating material.

Fast curing is particularly advantageous when coating or painting large components, such as rotor blades for wind turbines. However, due to the size of the surface, a relatively long time is required to coat the entire component, so the coating material used must have a long pot life and a long open time. Hereinafter, pot life refers to the time interval between mixing all the components of the coating material and the point at which the crosslinking reaction in the coating material has progressed to the point at which the coating material can no longer be processed. Hereinafter, open time refers to the time interval during which the applied coating material film can be corrected without impairing the leveling properties.

During the application of the coating material, the area that has been coated must be able to absorb the overspray that occurs when the adjacent area is painted in addition, without, for example, surface defects occurring due to poor leveling. Hereinafter, overspray refers to the material loss of the coating material caused when spraying. The material loss may be caused by the prior spraying of the workpiece due to the unfavorable orientation of the spray gun or in the case of a strong interruption of the workpiece, such as a grid. Overspray can also occur due to the coating material droplets that flow down from the side before the workpiece surface. Overspray absorption is thus the property that the applied coating material absorbs the material from the overspray to retain the desired smooth surface of the film or layer.

After applying a coating layer or film, it is desirable for the coating to dry or cure as quickly as possible. Forced drying at elevated temperatures is often not possible with large components, as this would require correspondingly large ovens. Therefore, rapid drying at room temperature is particularly desirable, especially when coating or painting very large components.

EP 2374836 A1 discloses binder systems crosslinking by Michael addition (hereinafter referred to as RMA systems) that have a favorable ratio of pot life to drying time. These binder systems exhibit a short drying time even at room temperature while maintaining a long pot life. EP 2374836 A1 is hereby expressly referenced as an integral part of this specification. A disadvantage of the known RMA systems is that the coating materials and coatings produced therefrom, in particular flexible matte coatings, do not exhibit the necessary and customary properties.

The object of the present invention is therefore to provide improved coating materials, coatings and coating systems based on RMA systems, which are suitable in particular for coating large components such as rotor blades.

This object is achieved by a coating material for producing a coating according to the main claim. Further embodiments are disclosed in the independent and dependent claims as well as in the description.

The coating material according to the invention comprises an RMA system having one or more C₁₂ acidic compounds A, one or more vinyl-like carbonyl compounds B and one or more catalysts C. Furthermore, it comprises one or more light stabilizers, one or more pot life extenders, one or more open time extenders, one or more inorganic and/or organic pigments and one or more matting agents.

In the following text, the term "light stabilizer" is understood to mean additives and adjuvants that protect coatings from UV light, in particular prevent or at least significantly delay the decomposition of polymers caused by UV radiation. The term "pot life extender" is understood to mean additives and adjuvants that, as a component of the mixed coating material, delay the curing of the coating material before application. They evaporate during application and thus do not affect, or in particular do not delay, the curing of the applied coating material. The term "open time extender" is understood to mean additives and adjuvants that remain in the coating material even after application and delay its curing to form a coating. The term "matting agent" is understood to mean additives and adjuvants that reduce the gloss of a coating or produce a matte finish. Matting agents create the necessary surface structure in the coating without impairing other characteristics and properties.

The coating material according to the present invention comprises at least

10 to 70, preferably 15 to 60, particularly preferably 20 to 55% by weight of CH-acidic compounds A,

4 to 40, preferably 8 to 35, particularly preferably 10 to 30% by weight of a vinyl-like carbonyl compound B,

0.1 to 15, preferably 0.2 to 10, particularly preferably 0.3 to 5% by weight of a latently basic catalyst C,

0.00001 to 10, preferably 0.5 to 5, particularly preferably 1 to 3% by weight of light stabilizers,

0.00001 to 20, preferably 0.01 to 10, particularly preferably 0.1 to 5% by weight of an open time extender,

0.00001 to 20, preferably 0.01 to 15, particularly preferably 0.1 to 10% by weight of a pot life extending agent,

0.00001 to 70, preferably 10 to 65, particularly preferably 15 to 40% by weight of inorganic and/or organic pigments,

0.00001 to 25, preferably 1 to 25, particularly preferably 5 to 20, very particularly preferably 8 to 15% by weight of matting agent,

The stated amounts are in each case based on the total amount of coating material.

According to the invention, compounds A and B are used in a substance ratio of A:B of 0.5:1 to 2:1, preferably 0.75:1 to 1.6:1, particularly preferably 0.9:1 to 1.3:1, very particularly preferably 0.95:1 to 1.1:1, the substance amounts being based on the acidic protons of compound A and on the vinyl-like carbonyl group of compound B.

According to the invention, catalyst C and compound A are used in a C:A molar ratio of 0.8:1 to 2.5:1, preferably 1.1:1 to 1.9:1, particularly preferably 1.3:1 to 1.7:1, wherein the molar ratios are based on the cation X ⁺ of catalyst C and the acidic protons of compound A.

Suitable CH acidic compounds A are compounds of the general formula I

in,

R is hydrogen, alkyl or aryl, and

Y and Y' are alkyl, aralkyl, aryl, alkoxy or amino, preferably primary amino, and Y and Y' may be the same or different.

Furthermore, the -C(=O)-Y and/or -C(=O)-Y' groups of formula I may be replaced by CN- or aryl groups.

According to the present invention, malonates, acetoacetates or mixtures thereof are preferably used. Particularly preferred are malonates with oligomeric and polymeric substituents, for example based on polyesters, polyurethanes, polyacrylates, epoxy resins, polyamides or polycarbonates. Particularly preferred are malonates with oligomeric and polymeric substituents based on polyesters, polyurethanes and/or polycarbonates. The acetoacetates used preferably contain oligomeric and polymeric substituents, for example based on polyols, polyvinyl alcohols, epoxy resins, hydroxyl-functionalized polyethers, polyesters or polyacrylates. Particularly preferred are acetoacetates with oligomeric and polymeric substituents based on polyesters and/or polyacrylates. Very particularly preferred compounds are selected from malonates with oligomeric and polymeric substituents based on polyesters, which are obtained by reacting at least malonic acid, dimethyl malonate and/or diethyl malonate with hexahydrophthalic acid and/or its anhydride and neopentyl glycol; and acetoacetates with oligomeric and polymeric substituents based on polyesters, which are obtained by reacting at least acetoacetic acid, methyl acetoacetate and/or ethyl acetoacetate with hexahydrophthalic acid and/or its anhydride and neopentyl glycol.

Suitable vinyl-like carbonyl compounds B are, for example, acrylates and/or maleates, in particular unsaturated acryloyl-functionalized compounds. According to the invention, acrylates composed of compounds containing 1 to 20 carbon atoms and at least 2, preferably 2 to 6, hydroxyl groups are preferred. Also preferred according to the invention are polyesters obtained by reacting maleic acid, fumaric acid and/or itaconic acid or their anhydrides with di- or polyhydroxy compounds which may contain monohydroxy compounds or carboxyl compounds. Further preferred are resins such as polyesters, polyurethanes, polyethers and/or alkyd resins, which accordingly contain activated unsaturated groups, such as urethane acrylates, polyether acrylates, multifunctional polyacrylates, polyalkyl maleates and polyacrylates obtained by reacting acrylic acid with epoxy resins. Particularly preferred according to the invention are butanediol diacrylate, hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, di(trimethylolpropane) tetraacrylate and dipentaerythritol hexaacrylate, as well as dipropylene glycol diacrylate and tripropylene glycol diacrylate.

Suitable latently basic compounds of catalyst C are, for example, substituted carbonates of the formula II:

in

R is hydrogen, alkyl or aralkyl (Ar-R) or a polymer,

X ⁺ is an alkali metal cation or an alkaline earth metal cation, especially lithium, sodium or potassium, or a quaternary ammonium salt or a quaternary phosphonium salt of formula (R') ₄ Y ⁺ ,

Wherein Y is nitrogen or phosphorus,

R' is the same or different and is hydrogen, alkyl, aryl (Aral-) or aralkyl or a polymer,

And among them

R and R' can form a ring structure

or

R and R' may be polymers.

According to the present invention, R is preferably alkyl or aralkyl, particularly preferably has the alkyl of 1 to 4 carbon atom.In addition, carbonate radical group and cation X ⁺ also can be present in the molecule with corresponding structure.In addition, R ' is preferably alkyl, particularly preferably has the alkyl of 1 to 4 carbon atom (particularly preferably has 3 to 4 carbon atoms).According to the present invention, preferably use sal monium carbonate and/or phosphonium carbonate.Suitable sal monium carbonate is for example methyl carbonate tetrahexyl ammonium, tetrahexyl ammonium bicarbonate, methyl carbonate tetradecyl trihexyl ammonium, methyl carbonate tetradecyl ammonium, methyl carbonate tetrabutyl ammonium, ethyl carbonate tetrabutyl ammonium, tetrabutyl ammonium bicarbonate, methyl carbonate tetrapropyl ammonium, ethyl carbonate tetrapropyl ammonium, tetrapropyl ammonium bicarbonate, methyl carbonate benzyl trimethyl ammonium, methyl carbonate trihexyl methyl ammonium or methyl carbonate trioctyl methyl ammonium.Particularly preferably use methyl carbonate tetrabutyl ammonium, ethyl carbonate tetrabutyl ammonium, tetrabutyl ammonium bicarbonate, methyl carbonate tetrapropyl ammonium, ethyl carbonate tetrapropyl ammonium, tetrapropyl ammonium bicarbonate and composition thereof.

Suitable light stabilizers include free radical scavengers such as aliphatic sterically hindered amines, for example, based on substituted 2,2,6,6-tetramethylpiperidines; UV absorbers such as 2-hydroxyphenylbenzotriazoles, 2-hydroxybenzophenones, 2-hydroxyphenyltriazines, or oxalic acid anilides; and quenchers such as organonickel compounds and peroxide decomposers such as thioethers or phosphites. Free radical scavengers such as aliphatic sterically hindered amines based on substituted 2,2,6,6-tetramethylpiperidines and/or UV absorbers such as 2-hydroxyphenylbenzotriazoles, 2-hydroxybenzophenones, 2-hydroxyphenyltriazines, and oxalic acid anilides are preferably used. Substituted 2,2,6,6-tetramethylpiperidines, 2-hydroxyphenyltriazines, 2-hydroxybenzophenones, and mixtures thereof are particularly preferred.

Suitable pot life extenders are short-chain alcohols having a volatility value of less than 35, preferably less than 20. Particularly suitable are alcohols having up to 6, preferably up to 4, particularly preferably up to 3 carbon atoms. Thus, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol and mixtures thereof can be used according to the invention.

Suitable open time extenders are basic NH-functional compounds having a _pKa value between 4 and 14. Preferred are succinimides, 1,2,4-triazoles, 1,2,3-benzotriazoles, 5,5-diphenylhydantoins, hydantoins, (RS)-3-ethyl-3-methylpyrrolidine-2,5-dione, and mixtures thereof. Particularly preferred are succinimides, 1,2,4-triazoles, 1,2,3-benzotriazoles, and mixtures thereof.

Suitable inorganic pigments are, for example, titanium dioxide, iron oxide, chromium oxide, chromium titanate, bismuth vanadate, cobalt blue and carbon black. Preferred inorganic pigments are titanium dioxide, iron oxide and carbon black. Suitable organic pigments are, for example, pigment yellow 151, pigment yellow 213, pigment yellow 83, pigment orange 67, pigment orange 62, pigment orange 36, pigment red 170, pigment violet 19, pigment violet 23, pigment blue 15:3, pigment blue 15:6, pigment green 7. Preferred pigments are pigment yellow 151, pigment orange 67, pigment red 170, pigment violet 19, pigment blue 15:3, pigment green 7.

Suitable matting agents are, for example, micronized amorphous silicas such as silica gel and precipitated silica, micronized and precipitated waxes such as polyethylene wax, polypropylene wax, polyamide wax or PTFE wax, and also micronized polymers such as urea-formaldehyde resins. Preferred matting agents are micronized and precipitated polyethylene wax, polypropylene wax, polyamide wax, PTFE wax and micronized urea-formaldehyde resin.

In another embodiment of the present invention, further additives and auxiliaries such as dispersing additives, functional fillers and/or leveling additives may be added to the coating material in order to improve the desired properties of the coating material and/or the coating.

The coating material may further comprise up to 25%, preferably 0.00001 to 8%, particularly preferably 0.00001 to 5% by weight of dispersing additives, the amounts stated being based on the total amount of the coating material. Suitable dispersing additives are, for example, high molecular weight block copolymers with pigment-affinity groups, highly branched polyesters, and acrylate-polyester copolymers with pigment-affinity groups. Preferred dispersing additives are high molecular weight block copolymers with pigment-affinity groups.

The coating material can additionally comprise up to 60, preferably 0.00001 to 50, particularly preferably 0.00001 to 40 weight % of functional fillers, wherein the amounts given are respectively based on the total amount of the coating material. Suitable fillers are, for example, carbonates such as chalk, limestone powder, calcite, precipitated calcium carbonate, dolomite, barium carbonate; sulfates such as barite, barium sulfate powder, calcium sulfate; silicates such as talc, pyrophyllite, chlorite, amphibole, mica, kaolin, wollastonite, shale powder, precipitated calcium silicate, precipitated aluminum silicate, precipitated calcium aluminum silicate, precipitated sodium aluminum silicate, feldspar, mullite; silicon dioxide such as quartz, fused quartz, cristobalite, diatomaceous earth, silica, precipitated silicon dioxide, pumice powder, perlite, calcium metasilicate; fibers, glass powder, glass beads and slag fused from glass or basalt. Preferably used fillers are barium sulfate, calcium carbonate and/or talc.

The coating material according to the invention may further contain up to 10%, preferably 0.00001 to 5%, particularly preferably 0.00001 to 2% by weight of a leveling additive, the amounts stated being based on the total amount of the coating material. Suitable leveling additives are, for example, medium- to high-viscosity polyacrylates with a medium molecular weight, silicones, modified silicones, fluorosurfactants, and sparingly volatile solvents with a volatility number of 150 to 200. Preferred leveling additives are silicones, modified silicones, and fluorosurfactants.

In another embodiment according to the invention, the coating material further comprises up to 50%, preferably 0.00001 to 40%, particularly preferably 0.00001 to 30% by weight of an aprotic solvent, the amounts stated being based on the total amount of the coating material. The term "aprotic solvent" is hereinafter understood to mean a solvent whose molecule contains no ionizable protons. Suitable aprotic solvents are, for example, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, ketones, esters, ethers, ether esters, in particular ethyl acetate, butyl acetate, acetone, n-butyl ketone, methyl isobutyl ketone, methoxypropyl acetate and dimethyl sulfoxide. Preferred solvents are ethyl acetate, butyl acetate, acetone, n-butyl ketone, methyl isobutyl ketone, methoxypropyl acetate and mixtures thereof.

The compound used as the catalyst C according to the present invention is a potential base because the carbonate according to formula II is in equilibrium with its dissociation product, carbon dioxide, and the corresponding hydroxide base or alkoxy base. As long as carbon dioxide cannot escape from the system, the equilibrium is on the carbonate side. Only when carbon dioxide is removed and a sufficient amount of base is present does crosslinking begin by Michael addition. When the coating material according to the present invention is stored in a closed container, carbon dioxide cannot escape therefrom, and the coating material according to the present invention is generally formulated in the form of a single-component system. However, if the individual components of the coating material according to the present invention are formulated in a multi-component system, storage stability can be improved. Therefore, for example, the catalyst component comprising catalyst C can be mixed with the binder component comprising C₁₂ acidic compound A and vinyl-like carbonyl compound B only within a short period of time before processing.

According to the present invention, C₂O₂ acidic compound A and vinyl-like carbonyl compound B may be included in the binder component together with the used light stabilizer, open time extender and pot life extender. The binder component may also contain pigments, fillers, other additives and solvents. Catalyst C and optionally other solvents and pot life extenders may be included in the catalyst component. In a preferred embodiment, C₂O₂ acidic compound A may be present in the first binder component, vinyl-like carbonyl compound B may be present in the second binder component and catalyst C may be present in the catalyst component. In such a three-component system, C₂O₂ acidic compound A is preferably included in the first binder component together with the open time extender and light stabilizer. Optionally, the first binder component may also contain pigments, fillers and other additives. The second binder component preferably contains vinyl-like carbonyl compound B. In addition, the second binder component may also contain pigments, fillers and other additives. Catalyst C is included in the catalyst component. In addition, the catalyst component may contain solvents and pot life extenders.

It is known that the addition of other ingredients that are customary for coating production reduces the storage stability of RMA systems. The coating materials according to the invention, which contain specially selected light stabilizers, open time extenders, pot life extenders, pigments, matting agents, dispersing additives, leveling additives, functional fillers, and aprotic solvents, have unexpectedly high storage stability compared to previously known coating materials based on RMA systems.

Furthermore, the properties of coatings produced from coating materials based on RMA systems differ from those of coatings produced from coating materials based on conventional binders, such as epoxy resins or polyurethanes, and are significantly negatively affected by the presence of other components of the coating material. Surprisingly, it has been shown that the coating materials according to the invention produce coatings with the properties necessary for use in wind turbine components, such as rotor blades, particularly weather stability, low-temperature resilience, wear resistance, and resistance to rain and sand erosion.

In a particularly preferred embodiment, the coating material according to the invention comprises at least:

10 to 70, preferably 16 to 60, particularly preferably 20 to 55% by weight of C₄-acidic compounds A, for example polyester-based malonic esters with oligomeric or polymeric substituents, obtained by reaction of at least malonic acid, dimethyl malonate and/or diethyl malonate with hexahydrophthalic acid and/or its anhydride and neopentyl glycol; and acetoacetic esters with oligomeric and polymeric substituents based on polyesters, obtained by reaction of at least acetoacetic acid, methyl acetoacetate and/or ethyl acetoacetate with hexahydrophthalic acid and/or its anhydride and neopentyl glycol,

4 to 40, preferably 8 to 35, particularly preferably 10 to 30% by weight of a vinyl-like carbonyl compound B, for example butanediol diacrylate, hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, di(trimethylolpropane) tetraacrylate and/or dipentaerythritol hexaacrylate,

0.1 to 15, preferably 0.2 to 10, particularly preferably 0.3 to 5% by weight of a latently basic catalyst C, for example tetrabutylammonium methylcarbonate, tetrabutylammonium ethylcarbonate, tetrabutylammonium hydrogen carbonate, tetrapropylammonium methylcarbonate, tetrapropylammonium ethylcarbonate, tetrapropylammonium hydrogen carbonate and mixtures thereof,

0.00001 to 10, preferably 0.5 to 5, particularly preferably 1 to 3% by weight of light stabilizers, for example substituted 2,2,6,6-tetramethylpiperidines, 2-hydroxyphenyltriazines, 2-hydroxybenzophenones and mixtures thereof,

0.00001 to 20, preferably 0.01 to 10, particularly preferably 0.1 to 5% by weight of open time extenders, for example succinimides, 1,2,4-triazoles, 1,2,3-benzotriazoles and mixtures thereof,

0.00001 to 20, preferably 0.01 to 15, particularly preferably 0.1 to 10% by weight of a pot life extender, for example methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol and mixtures thereof,

0.00001 to 70, preferably 10 to 65, particularly preferably 15 to 40% by weight of inorganic and/or organic pigments, for example titanium dioxide, iron oxides, carbon black, Pigment Yellow 151, Pigment Orange 67, Pigment Red 170, Pigment Violet 19, Pigment Blue 15:3, Pigment Green 7 and mixtures thereof,

0.00001 to 25, preferably 1 to 25, particularly preferably 5 to 20, very particularly preferably 8 to 15% by weight of matting agents, for example micronized and precipitated polyethylene waxes, polypropylene waxes, polyamide waxes, PTFE waxes and micronized urea-formaldehyde resins and mixtures thereof,

0 to 25, preferably 0.00001 to 8, particularly preferably 0.00001 to 5% by weight of dispersing additives, for example high molecular weight block copolymers having pigment-affinity groups,

- 0 to 10, preferably 0.00001 to 5, particularly preferably 0.00001 to 2% by weight of leveling additives silicone, modified silicone and fluorinated surfactants,

0 to 60, preferably 0.00001 to 40, particularly preferably 0.00001 to 30% by weight of functional fillers, for example barium sulfate, calcium carbonate and/or talc, and

0 to 50, preferably 0.00001 to 40, particularly preferably 0.00001 to 30% by weight of aprotic solvents, for example ethyl acetate, butyl acetate, acetone, n-butyl ketone, methyl isobutyl ketone, methoxypropyl acetate and mixtures thereof,

The stated amounts are in each case based on the total amount of coating material.

The coating materials according to the present invention can be used to produce flexible coatings, such as for coating rotor blades for wind turbines. The coating materials and coatings according to the present invention surprisingly have significantly higher storage stability than previously known RMA coating systems and RMA coatings. They also exhibit improved drying behavior. Furthermore, coatings obtained from the coating materials according to the present invention have improved light stability, particularly reduced yellowing and higher gloss retention.

The coating materials according to the invention have a pot life of at least 1 hour, preferably at least 2 hours, and particularly preferably between 2 and 4 hours. Typically, the pot life is determined by the flow time from the flow cup. The end of the pot life is determined as the point in time at which the flow time shows a value twice the start of the flow time. The test methods are described in detail below in the examples. In addition, the coating materials according to the invention exhibit an open time of at least 15 minutes, preferably at least 20 minutes, and particularly preferably at least 25 minutes. In addition to a long pot life and open time, the coating materials according to the invention surprisingly exhibit an unusually wide climatic window in which they can be processed without damage. They are processable, for example, at temperatures of up to 45°C and at relative humidity of up to 99%. In addition, they exhibit long overspray absorption, for example within a time interval of more than 15 minutes. Unlike conventionally used polyurethane-based coating materials, the coating materials according to the invention have significantly shorter drying times.

In a preferred embodiment, the coating material according to the invention is used to produce a topcoat for fiber-reinforced plastic substrates. Components made of fiber-reinforced plastic must be sufficiently weather-resistant for outdoor use, i.e., resistant to UV radiation and moisture. Therefore, components used outdoors, such as rotor blades of wind turbines, are often protected by applying a corresponding floor coating. Furthermore, the topcoat of the rotor blades must be sufficiently flexible and durable at ambient temperatures between -40 and +60°C to avoid or at least reduce the erosive effects of particles such as dust, ice particles, or raindrops. In addition to high weather resistance, the coating according to the invention also possesses the necessary low-temperature elasticity, scratch resistance, and resistance to rain and sand erosion.

Due to their properties, the coating materials according to the invention are particularly suitable for coating large components. In particular, they are used to coat large-area components consisting of fiber-reinforced plastic substrates, such as for example for constructing rotor blades in wind turbines.

The present invention also relates to a method for coating a component. The method according to the invention comprises the following steps: (a) applying the coating material according to the invention to the surface of a substrate, and (b) curing the applied coating material at a temperature of 5 to 45° C., preferably 15 to 40° C., particularly preferably 20 to 35° C., for 0.5 to 12 hours, preferably 1 to 6 hours, particularly preferably 1 to 4 hours.

The coating material according to the invention has an above-average high solids content and therefore contains a low proportion of volatile organic substances, such as solvents. The solids content is defined as the mass fraction of the coating material remaining as a residue after evaporation at 105°C for 30 minutes. The solids generally consist essentially of binders, non-volatile additives, pigments, and fillers. The solids content of the coating material according to the invention is between 65 and 95%, preferably between 70 and 90%, and particularly preferably between 75 and 85% by weight, based on the total weight of the coating material.

Coating materials with a high solids content are often difficult to process using conventional spraying methods. In contrast, the coating material according to the present invention can be applied easily by means of hydraulic, very high-pressure spraying (airless), air-assisted airless spraying (airmix), and pneumatic or compressed air spraying. Even with these spraying methods, surprisingly high-quality surfaces are achieved. Particularly suitable according to the present invention are airless and airmix spraying methods, as well as application by roller.

Components made of fiber-reinforced plastics often have very rough surfaces that must be polished before coating, for example by filling and grinding the surface. These pretreatment methods are known and familiar to those skilled in the art. The coating according to the invention is usually applied to the thus pretreated surface. It can be applied in such a high layer thickness that the cured coating does not impair the surface quality even with insufficiently pretreated substrate surfaces. The coating according to the invention can have a dry layer thickness of between 80 and 150 μm.

In another embodiment of the method, all components of the coating material used are mixed before application. This mixing can be done manually or by machine. In another embodiment, a coating system having at least one additional coating layer can be produced by applying and curing a further coating material on top of a first coating layer. This second coating layer can also be applied only partially, thereby creating colored patterns, such as luminous warning stripes, or in particular reinforcements, such as edge protection.

Since the coating materials according to the invention can be cured at room temperature, they are particularly suitable for coating large components, such as rotor blades for wind turbines. In currently operating wind turbines, rotor blades with blade lengths of up to 65 meters are used onshore and rotor blades with blade lengths of up to 85 meters are used offshore.

Example

The coating material was prepared according to standard paint technology known and familiar to those skilled in the art.The catalyst solution used in Example Formulation 1 was prepared by adding 42.8 g diethyl carbonate and 26.1 g isopropyl alcohol to a solution of 17.1 g tetrabutylammonium hydroxide in 14 g water.

Example Formulation 1: Topcoat

To evaluate the storage stability of the coating materials, the pot life and drying time of Example Formulation 1 were determined. Samples were tested after 1 day of storage at 23°C, 28 days of storage at 40°C, and 1 year of storage at 20 to 23°C or used to produce coatings.

Determination of Pot Life: The pot life is determined using a flow cup. In this method, a defined volume of liquid is filled into a cup with a defined nozzle at its bottom. The coating material flows through the nozzle, and the flow time is measured from the time the liquid jet exits until it is interrupted. All preparations and measurements are carried out at a temperature of 23°C. First, all components of the coating material are mixed and the flow time of the mixture is immediately measured (initial flow time). The measurement is repeated at regular intervals. The end of the pot life is reached when the flow time is twice the initial flow time.

Determination of Drying Time: To determine the drying time, a drying recorder (drying time measuring instrument from BYK Gardener) is used. The coating material to be tested is evenly applied to a glass strip using a film puller. The glass strip is then placed in a line recorder. A needle is then placed on the coating and pulled across the drying film at a defined, constant speed. This produces a characteristic drying profile of the coating, with individual time segments indicating different curing states: leveling or open time, initial marks, film tearing, and surface marks. Curing of the coating material begins at the end of the open time, i.e., at the point at which scratches left by the needle remain visible in the applied film. It ends at the surface marks, i.e., at the point at which the needle no longer leaves visible marks in the applied film.

To evaluate the storage stability of the coating materials, the quality of coatings produced from various stored coating materials of Example Formulation 1 was also tested. Elongation at break and weathering stability were measured. Samples were used to produce coatings after storage for one day at 23°C, 28 days at 40°C, and one year at 20 to 23°C. To produce the test specimens, Example Formulation 1 was applied to primed aluminum panels using a cup spray gun and cured at room temperature.

Determination of Elongation at Break: The elongation at break is determined using a mandrel bend test. To do this, the specimen is bent around a mandrel. The smaller the radius of the mandrel around which the sheet can be bent without damaging or breaking the coating, the greater the elongation at break of the coating. The mandrel diameter is reported as the measured value.

Determination of weathering stability: To evaluate the weathering stability of a coating, the change in color tone (ΔE) and the change in gloss value (residual gloss value) are used. For this purpose, the color tone and gloss of the specimens are first determined. Subsequently, the specimens are exposed to artificial aging, which simulates natural erosion by cyclic use of radiation, humidity and elevated temperature. For this purpose, a test cycle consisting of a drying phase and a condensation phase is repeated for 500 hours. In the drying phase of the test cycle, the specimens are irradiated with a QUV-B (313) lamp at a blackboard temperature of 60°C for 4 hours, and in the subsequent 4-hour condensation phase, water vapor is condensed on the specimens in water vapor at a blackboard temperature of 50°C. After aging, the color tone and gloss of the specimens are re-determined. The change in color tone of the coating is determined using the CIELab system and is given as the ΔE value. The change in gloss is given as the residual gloss value. For this purpose, the gloss of the coating surface is determined as a reflectometer value. The reflectometer value of the sample is defined as the ratio of the light beam reflected in the mirror direction by the sample surface and a glass surface with a refractive index of 1.567. The measured values are determined at an angle of 60° using a conventional reflectometer. As residual gloss value, the difference in the reflectometer value of the sample before and after ageing is given, normalized to the reflectometer value before ageing.

Table: Storage stability of Example Formula 1

store 1 day, 23°C 28 days, 40℃ 1 year, 20-23℃ Applicable period 3h 3h 3h Opening hours 16min 17min 15min Surface trace end point 45min 43min 47 minutes Elongation at break 20mm 20mm 20mm Hue change (△E) 0.28 0.26 0.30 Residual gloss value 96% 96% 97%

As shown in the table above, the coating material according to the invention has a high storage stability. After prolonged storage at elevated temperatures, the coating material itself does not show a deterioration in its processability. The coatings thus prepared do not show any impairment in their properties either.

Claims (20)

1. A coating material for preparing a coating, having at least the following properties: -15 to 70% by weight of one or more CH acidic compounds A, -4 to 40% by weight of one or more vinyl-like carbonyl compounds B, -0.1 to 15% by weight of one or more potentially basic catalysts C, -0.00001 to 10% by weight of one or more light stabilizers, said light stabilizers being selected from free radical scavengers, UV absorbers, quenchers, and peroxide decomposers. -0.00001 to 20% by weight of one or more open-time prolonging agents, said open-time prolonging agents being selected from basic NH functional compounds having a _pKa value between 4 and 14. -0.00001 to 20% by weight of one or more pot life extenders, said pot life extender being selected from alcohols having up to 6 carbon atoms and a volatility of less than 35. -0.00001 to 70% by weight of one or more inorganic and/or organic pigments, said pigments being selected from titanium dioxide, iron oxide, chromium oxide, chromium titanate, bismuth vanadate, cobalt blue, carbon black, pigment yellow 151, pigment yellow 213, pigment yellow 83, pigment orange 67, pigment orange 62, pigment orange 36, pigment red 170, pigment violet 19, pigment violet 23, pigment blue 15:3, pigment blue 15:6, pigment green 7, and -0.00001 to 25% by weight of one or more matting agents, said matting agent being selected from silica gel, precipitated silica, micronized wax, precipitated wax and micronized polymer. Based on the total amount of coating material. 2. The coating material according to claim 1, wherein the CH acidic compound A is a compound of general formula I. in R is hydrogen, alkyl, or aryl. Y is alkyl, aralkyl, aryl, alkoxy, or amino, and Y' is an alkyl, aralkyl, aryl, alkoxy, or amino group. 3. The coating material according to claim 1 or 2, wherein the vinyl-like compound B is an acrylate and/or maleate. 4. The coating material according to claim 1 or 2, characterized in that the catalyst C is a substituted carbonate of the following formula. in R is a hydrogen, alkyl, aralkyl, or polymer group. X ⁺ is an alkali metal or alkaline earth metal cation, or a quaternary ammonium salt or quaternary phosphonium salt of formula (R') _4Y ⁺ . in Y represents nitrogen or phosphorus. R' can be the same or different, and can be hydrogen, alkyl, aryl, or aralkyl or a polymer. Furthermore, R and R' form a ring structure or are polymers. 5. The coating material according to claim 1 or 2, characterized in that the coating material further comprises up to 25% by weight of one or more dispersing additives. 6. The coating material according to claim 5, wherein the dispersing additive is selected from high molecular weight block copolymers with pigment affinity groups, highly branched polyesters, and acrylate-polyester copolymers with pigment affinity groups. 7. The coating material according to claim 1 or 2, characterized in that the coating material further comprises up to 60% by weight of one or more functional fillers. 8. The coating material according to claim 7, wherein the functional filler is selected from carbonates, sulfates, silicates and silicon dioxide. 9. The coating material according to claim 1 or 2, characterized in that the coating material further comprises up to 50% by weight of one or more aprotic solvents. 10. The coating material according to claim 9, wherein the solvent is selected from aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, ketones, esters, ethers, ether esters and dimethyl sulfoxide. 11. The coating material according to claim 9, wherein the solvent is selected from ethyl acetate, butyl acetate, acetone, n-butyl ketone, methyl isobutyl ketone, and methoxypropyl acetate. 12. The coating material according to claim 1 or 2, characterized in that the coating material further comprises up to 10% by weight of one or more leveling additives. 13. The coating material according to claim 12, wherein the leveling additive is selected from medium to high viscosity polyacrylates with medium molecular weight, silicones, modified silicones, fluorinated surfactants, and non-volatile solvents with a volatility number of 150 to 200. 14. Use of the coating material according to any one of claims 1 to 13 for preparing at least one coating. 15. The use according to claim 14, characterized in that the coating material is used to prepare a topcoat. 16. A method for coating parts, comprising the steps of: (a) applying a coating material according to any one of claims 1 to 13 to a substrate, and (b) curing the applied layer at a temperature between 5 and 45°C for a period of 0.5 to 12 hours. 17. The method according to claim 16, characterized in that the coating material is applied by means of hydraulic spraying, pneumatic spraying, compressed air spraying or by means of a roller. 18. The method according to claim 16 or 17, characterized in that all components of the coating material are mixed prior to step (a). 19. A component having at least one coating prepared from a coating material according to any one of claims 1 to 13. 20. The component according to claim 19, wherein the component is a moving blade of a wind turbine.