Aqueous topcoat composition for decorative-finish films

Abstract

The invention relates to an aqueous topcoat composition for decorative-finish films containing 50 to 95 wt.% cross-linkable, OH-functional acrylic emulsion relative to the total weight of the topcoat composition, the aqueous topcoat composition being free of formaldehyde-based compounds. The invention also relates to a method for producing such an aqueous topcoat composition, a kit for producing a topcoat for decorative-finish films, a decorative-finish film, a method for producing a decorative-finish film, a decorative-finish film which is obtained or can be obtained by means of such a method, the use of a topcoat composition or a kit for producing a topcoat for a decorative-finish film, and the use of a decorative-finish film for coating wooden beams, edges and / or pieces of furniture.

Description

[0001] Aqueous topcoat composition for decorative finish films

[0002] The present invention relates to an aqueous topcoat composition for decorative finish films, a process for producing such an aqueous topcoat composition, a kit for producing a topcoat for decorative finish films, a decorative finish film, a process for producing a decorative finish film, a decorative finish film obtained or obtainable by such a process, the use of a topcoat composition or a kit for producing a topcoat for a decorative finish film and the use of a decorative finish film for coating wooden supports, edges and / or furniture.

[0003] Films are among the solid coating materials used for wood-based materials in furniture manufacturing, interior design, and other areas. In this context, films primarily refer to thin sheets or rolls made of metals, plastics, or impregnated cellulose / pigment mixtures. During use, these films can exhibit both decorative and functional and protective properties, such as resistance to mechanical stress.

[0004] Decorative finish films are special, printed or colored papers with a varnished surface. The properties of decorative finish films are determined by the carrier material, the print, and especially the topcoat. The components carrier material, color layer, and varnish layer influence the external appearance of the decorative finish film and the properties and behavior of the film in further processing, such as the coating of furniture. Various varnish systems are known from the state of the art that are used as topcoats in the production of decorative finish films. Acid-curing varnishes (SH varnishes) are two-component coating materials containing urea and melamine resins and an acidic hardener as a catalyst. They cure through a polycondensation reaction. The disadvantage of these systems is that the urea and melamine resins are formaldehyde-based, and formaldehyde is released during crosslinking.In addition, furniture coated with such varnishes can also release formaldehyde. Formaldehyde is classified as toxic and carcinogenic and therefore poses a health hazard.

[0005] Radiation-curing coatings are cured by irradiation, particularly ultraviolet radiation (so-called UV coatings) or electron beam radiation (so-called EBC coatings). One example of such radiation-curing coatings is monomeric acrylic acid compounds that cure with photoinitiators under UV radiation. The disadvantage of such radiation-curing systems is that special radiation-emitting devices and installations are required for curing, which involves additional costs and time. Such radiation-curing coatings cannot be used on conventional machines for the production of decorative finish films, where crosslinking occurs through thermal dryers.

[0006] The object of the invention was therefore to provide an aqueous topcoat composition for decorative finish films that at least partially overcomes one or more disadvantages of the prior art. Based on the prior art explained above, one object of the invention was to provide a topcoat composition that is less harmful, toxic, and carcinogenic both before, during, and after crosslinking. At the same time, the topcoat composition should be usable on conventional machines for producing decorative finish films. Furthermore, the topcoat composition should have good processing properties and, as a crosslinked topcoat for a decorative finish film, exhibit good decorative, as well as good functional and protective properties, such as good resistance to mechanical stress.

[0007] A further object of the present invention was to provide a decorative finish film with good decorative, functional, and protective properties, such as good resistance to mechanical stress. Such a decorative finish film should not release any harmful compounds even after coating wooden supports, edges, and / or furniture.

[0008] All or some of these objects are achieved according to the invention by an aqueous topcoat composition according to claim 1, a process according to claim 7, a kit according to claim 9, a decorative finish film according to claim 11, a process according to claim 18, a decorative finish film according to claim 23, a use according to claim 24 and a use according to claim 25.

[0009] Advantageous embodiments of the invention are specified in the dependent claims and are explained in detail below.

[0010] The invention provides an aqueous topcoat composition for decorative finish films, containing, based on the total weight of the topcoat composition, 50 to 95 wt.% of crosslinkable OH-functional acrylic emulsion, wherein the aqueous topcoat composition is free of formaldehyde-based compounds.

[0011] Surprisingly, it has been found that the aqueous topcoat composition according to the invention for decorative finish films has good processing properties and can be used on conventional machines for producing decorative finish films. At the same time, after crosslinking, the topcoat composition exhibits good decorative, functional, and protective properties, such as good resistance to mechanical stress. Furthermore, no irradiation is required to crosslink the topcoat composition, and the topcoat composition exhibits few or no health-endangering properties. This can be attributed to the fact that the topcoat composition is free of formaldehyde-based compounds. Formaldehyde-based compounds are understood to mean, in particular, compounds in the production of which formaldehyde is used. These include, in particular, melamine resins and urea resins.

[0012] OH-functional means that the acrylic emulsion contains hydroxyl groups. These hydroxyl groups can react preferentially with isocyanates, especially polyisocyanates, thus crosslinking the crosslinkable OH-functional acrylic emulsion.

[0013] The aqueous topcoat composition according to the invention contains, based on the total weight of the topcoat composition, 50 to 95 wt.% of crosslinkable OH-functional acrylic emulsion. According to a preferred embodiment, the aqueous topcoat composition contains, based on the total weight of the topcoat composition, 60 to 90 wt.%, in particular 70 to 85 wt.% of crosslinkable OH-functional acrylic emulsion.

[0014] The crosslinkable OH-functional acrylic emulsion preferably has a solids content of 20 to 70 wt.%, in particular 30 to 60 wt.% or 40 to 50 wt.%. Such a solids content of the OH-functional acrylic emulsion ensures particularly good processing properties of the aqueous topcoat composition.

[0015] Furthermore, the crosslinkable OH-functional acrylic emulsion preferably has a shear rate of 100 s _1 a viscosity, determined according to DIN EN ISO 3219, of 5 to 500 mPas, in particular of 10 to 100 mPas or 15 to 40 mPas. Such a viscosity of the OH-functional acrylic emulsion enables good processability of the waterborne topcoat composition.

[0016] In addition, the crosslinkable OH-functional acrylic emulsion preferably has a

[0017] Minimum film-forming temperatures of 30 to 220 °C, particularly 35 to 100 °C or 40 to 70 °C, are recommended. A minimum film-forming temperature that is too high prevents film formation at the temperatures used in conventional machines for producing decorative finish films.

[0018] Furthermore, the crosslinkable OH-functional acrylic emulsion preferably has a glass transition temperature of 20 to 150 °C, in particular of 30 to 110 °C or of 40 to 70 °C.

[0019] Furthermore, the crosslinkable OH-functional acrylic emulsion preferably has a hydroxyl number, based on the solids content of the crosslinkable OH-functional acrylic emulsion, of 10 to 500 mg KOH / g, in particular of 30 to 300 mg KOH / g or of 50 to 150 mg KOH / g. Such a hydroxyl number enables uniform and sufficient crosslinking of the OH-functional acrylic emulsion and thus ensures good functional and protective properties, such as good resistance to mechanical stress, of the topcoat.

[0020] Furthermore, the crosslinkable OH-functional acrylic emulsion is preferably an OH-functional copolymer emulsion, in particular an OH-functional acrylic-methacrylic-styrene copolymer emulsion. It has been shown that such an OH-functional acrylic emulsion has particularly good processing properties, and topcoats produced therefrom have particularly good functional and protective properties.

[0021] Finally, the crosslinkable OH-functional acrylic emulsion is preferably crosslinkable with isocyanates, especially polyisocyanates, resulting in a polyurethane. The resulting crosslinked polyurethane topcoat exhibits good decorative, functional, and protective properties, such as good resistance to mechanical stress.

[0022] According to a further preferred embodiment, the aqueous

[0023] The topcoat composition has a flow time of 5 to 50 seconds, particularly 11 to 22 seconds, at 23 °C, determined using a flow cup with a nozzle diameter of 6 mm according to ISO 2431. This flow time ensures particularly good processing properties of the waterborne topcoat composition.

[0024] According to a further embodiment of the invention, the aqueous topcoat composition has a pH of 5 to 11, in particular of 6 to 10 or of 7 to 9, at 25°C. A pH that is too high or too low poses a health risk during processing of the aqueous topcoat composition. Furthermore, if the pH of the topcoat composition is too low, the topcoat cannot cure sufficiently and completely.

[0025] Furthermore, the aqueous topcoat composition may preferably contain, based on the total weight of the topcoat composition, 0.1 to 20 wt.%, in particular 1 to 15 wt.% or 2 to 10 wt.% of additives.

[0026] In particular, the additives are wetting agents, dispersants, defoamers, leveling additives, rheology additives, matting agents, surface additives, and / or additives for improving scratch resistance. Such additives improve the processing properties of the topcoat composition and / or the decorative, functional, and / or protective properties of a topcoat produced therefrom.

[0027] Suitable wetting agents, dispersants, defoamers, surface additives and / or additives for improving scratch resistance are known to the person skilled in the art.

[0028] Suitable matting agents include, for example, amorphous silicate and / or wax dispersions, for example based on oxidized HDPE. Finally, the aqueous topcoat composition may contain, based on the total weight of the topcoat composition, 0.1 to 10 wt.%, in particular 0.5 to 7.5 wt.% or 1 to 5 wt.%, of film-forming aids.

[0029] Suitable film binding agents are esters such as 2,2,4-trimethyl-l,3-pentanediol monoisobutyrate, ether alcohols such as (di)ethylene glycol monobutyl ether and / or glycols such as ethanediol or propanediol.

[0030] According to a particularly preferred embodiment, the aqueous topcoat composition according to the invention contains, in each case based on the total weight of the aqueous topcoat composition, 70 to 85 wt.% crosslinkable OH-functional acrylic emulsion, 2 to 10 wt.% additives, 1 to 5 wt.% film-forming aids and water.

[0031] According to a further particularly preferred embodiment, the aqueous topcoat composition according to the invention consists of, in each case based on the total weight of the aqueous topcoat composition, 70 to 85 wt.% crosslinkable OH-functional acrylic emulsion, 2 to 10 wt.% additives, 1 to 5 wt.% film-forming aids and water.

[0032] The sum of all components of the aqueous topcoat composition according to the invention amounts to 100 wt. %, based on the total weight of the aqueous topcoat composition. According to a preferred embodiment of the aqueous topcoat composition according to the invention, the amounts missing to 100 wt. % are compensated by water.

[0033] The invention further provides a process for producing an aqueous topcoat composition according to the invention, comprising i. providing a crosslinkable OH-functional acrylic emulsion, water, and optionally additives and / or film-binding aids, ii. mixing the crosslinkable OH-functional acrylic emulsion, the water, and optionally the additives and / or the film-binding aid in a mixing ratio such that the aqueous topcoat composition obtained by mixing contains 50 to 95 wt.% crosslinkable OH-functional acrylic emulsion, based on the total weight of the aqueous topcoat composition.

[0034] What has been said in connection with the aqueous topcoat composition according to the invention regarding the aqueous topcoat composition and / or the crosslinkable OH-functional acyl emulsion and / or the additives and / or the film-binding aid can equally also apply to the aqueous topcoat composition and / or the crosslinkable OH-functional acyl emulsion and / or the additives and / or the film-binding aid of the process according to the invention.

[0035] The invention also relates to a kit for producing a topcoat for decorative finish films comprising a component 1 and a component 2, wherein component 1 is an aqueous topcoat composition according to the invention and component 2 is an aqueous hardener component, wherein the aqueous hardener component contains isocyanate, in particular polyisocyanate.

[0036] By mixing component 1 and component 2 of such a kit, then applying the mixture to a carrier material and crosslinking, a decorative finish film with good decorative as well as good functional and protective properties, such as good resistance to mechanical stress, can be obtained.

[0037] The aqueous hardener component preferably contains, based in each case on the total weight of component 2, isocyanate, in particular polyisocyanate, in an amount of 1 to 25 wt. %, in particular 5 to 20 wt. %. The polyisocyanate preferably has an NCO content of 5 to 30 wt. %, in particular 10 to 20 wt. %. Such a hardener component can cure the aqueous topcoat composition according to the invention and react with it to form a polyurethane topcoat layer having good decorative, as well as good functional and protective properties, such as good resistance to mechanical stress. If the amount of isocyanate and / or the NCO content is too low, curing is incomplete.

[0038] The invention further relates to a decorative finish film comprising a carrier material and a topcoat layer, wherein the topcoat layer is a polyurethane layer which can be produced by crosslinking an aqueous topcoat composition according to the invention with an aqueous hardener component described above.

[0039] Such a decorative finish film exhibits good decorative, functional, and protective properties, such as good resistance to mechanical stress. Such a decorative finish film can also be used to coat wooden supports, edges, and / or furniture and does not release any harmful compounds before or after coating.

[0040] The topcoat layer can be applied over the entire surface or partially to at least one side of the substrate. If the topcoat layer is applied over the entire surface of the substrate, the decorative finish film exhibits uniform and homogeneous surface properties. If the topcoat layer is applied partially to the substrate, the decorative finish film exhibits a textured surface, which can be structured differently depending on the desired appearance and properties.

[0041] Various materials can be used as the carrier material for the decorative finish film. The carrier material is preferably made of plastic and / or paper, in particular polyethylene terephthalate, polypropylene and / or paper. The carrier material is particularly preferably made of paper. According to a preferred embodiment, the topcoat layer has a grammage of 3 to 15 mg / m². 2 , especially from 4 to 12 g / m 2 or from 5 to 11 g / m 2Such a grammage ensures the positive properties of the topcoat layer described above. If the grammage is too low, the decorative finish film will not exhibit the desired good functional and protective properties, such as good resistance to mechanical stress. At higher grammages, larger quantities of topcoat composition are required, making the decorative finish film less resource-efficient and cost-effective.

[0042] The decorative finish film can comprise a colored layer between the carrier material and the topcoat layer. Such a colored layer can be obtained, in particular, by printing the carrier material using flexographic printing, digital printing, and / or gravure printing, in particular rotogravure printing. Such a colored layer provides the desired visual impression to be achieved with the decorative finish film. The colored layer preferably contains binders, in particular protein binders, especially casein, and pigments. Suitable pigments for the colored layer of decorative finish films are known to those skilled in the art.

[0043] According to a preferred embodiment, the decorative finish film comprises a transparent primer layer between the color layer and the topcoat layer, wherein the transparent primer layer is transparent to electromagnetic waves with wavelengths from 400 nm to 780 nm. Such a transparent primer layer can improve the adhesion of the topcoat layer to the color layer, while simultaneously preserving the visual impression of the decorative finish film achieved by the color layer. Particularly preferably, the transparent primer layer contains a crosslinked polyacrylate.

[0044] According to another preferred embodiment, the decorative finish film comprises a pigmented primer layer between the carrier material and the topcoat layer. Such a pigmented primer layer can achieve a uniform and homogeneous color impression of the decorative finish film and simultaneously improve the adhesion between the carrier material and the topcoat layer. The pigmented primer layer preferably contains a crosslinked polyacrylate and pigments; in particular, the pigmented primer layer contains pigments in an amount of 1 to 70 wt.%, in particular 2 to 60 wt.%, or 5 to 40 wt.%, based on the total weight of the pigmented primer layer.

[0045] In a preferred embodiment, the decorative finish film has the following layer structure from one side to the opposite side: carrier material, color layer, optionally transparent primer layer, top coat layer.

[0046] In another preferred embodiment, the decorative finish film has the following layer structure from one side to the opposite sides: carrier material, pigmented primer layer, top coat layer.

[0047] According to a preferred embodiment, the decorative finish film has a grammage of 25 to 100 g / m 2 , especially from 45 to 82 g / m 2 This weight ensures sufficient stability of the decorative finish film and allows it to be used on wooden supports, edges, and / or furniture. If the weight is too low, the decorative finish film tears very easily during transport. If the weight is too high, larger quantities of material are required, making the decorative finish film less resource- and cost-efficient.

[0048] The decorative finish film is particularly preferably free of formaldehyde-based compounds. This means that the decorative finish film does not emit harmful formaldehyde and does not exhibit any health-threatening properties.

[0049] The invention further provides a process for producing a decorative finish film, comprising: i. providing a carrier material, an aqueous topcoat composition according to the invention, and an aqueous hardener component; ii. mixing the aqueous topcoat composition and the aqueous hardener component; iii. applying the mixture prepared in step ii. to the carrier material; iv. crosslinking the aqueous topcoat composition and the aqueous hardener component.

[0050] Such a process can be used to produce a decorative finish film with the positive properties described above. Furthermore, the process can be used on conventional machines for producing decorative finish films.

[0051] The application in step iii can be carried out, for example, using doctor blade dispensing systems. Application can be carried out, in particular, by roller doctor coating.

[0052] What has been said above regarding the decorative finish film according to the invention, the carrier material and / or the aqueous hardener component can equally apply to the decorative finish film, the carrier material and / or the aqueous hardener component of the process according to the invention.

[0053] Preferably, the mixing in step ii. is carried out in a mixing ratio of aqueous topcoat composition to aqueous hardener component of 20:1 to 1:1 by weight, in particular of 15:1 to 3:1 by weight or of 12:1 to 6:1 by weight. With a mixture prepared in this way, crosslinking in step iv. can be complete and uniform.

[0054] Furthermore, crosslinking in step iv preferably takes place at 80 to 250 °C, especially at 100 to 230 °C. At this temperature, crosslinking can occur rapidly. A lower temperature increases the time required for crosslinking and is therefore less efficient. A higher temperature leads to increased energy consumption and is therefore less efficient.

[0055] The crosslinking in step iv. preferably takes place in a thermal dryer, in particular a flotation dryer. Preferably, the crosslinking in step iv. takes place without electron beam curing and without UV curing, in particular without radiation curing. The process can therefore be used on conventional machines for producing decorative finish films, and in particular, no special radiation-emitting devices or installations are required for crosslinking.

[0056] The method according to the invention may comprise the following step before step iii: a. Printing the carrier material with an ink layer, wherein the printing is carried out in particular by flexographic printing, digital printing and / or gravure printing, in particular by rotogravure printing.

[0057] A decorative finish film produced in this way can therefore have the desired optical properties, in particular patterns and colors.

[0058] Furthermore, the method according to the invention can comprise the following steps: b. applying a primer composition to the carrier material, in particular wherein the primer composition contains a crosslinkable polyacrylate, wherein the primer composition optionally contains pigments, c. crosslinking the primer composition.

[0059] The preferred sequence of process steps of the process according to the invention is: step i., step ii., optionally step a., optionally step b., optionally step c., step iii., step iv. The process according to the invention can be carried out using an inline process. The process steps of printing the substrate material and applying the mixture of aqueous topcoat composition and aqueous hardener component are carried out in one and the same machine. For this purpose, a coating system can be installed at the end of a printing press. Alternatively, the application of the mixture of aqueous topcoat composition and aqueous hardener component can take place offline in a separate coating system.

[0060] The invention further provides a decorative finish film obtained or obtainable by the process according to the invention.

[0061] The invention further provides for the use of an aqueous topcoat composition according to the invention or a kit according to the invention for producing a topcoat for decorative finish films. This use enables the efficient production of a topcoat for decorative finish films. The topcoat produced in this way exhibits good functional and protective properties, such as good resistance to mechanical stress.

[0062] Finally, the invention relates to the use of a decorative finish film according to the invention for coating wooden supports, edges, and / or furniture, in particular shelves. Wooden supports, edges, and / or furniture coated in this way are then decorated as desired, particularly with regard to color and feel, and are also well protected, for example, against mechanical stress such as abrasion and scratching.

[0063] The coating can be carried out in particular in flat presses, laminating systems or wrapping systems.

[0064] The principle of the invention will be explained in more detail below using non-limiting examples.

[0065] Example 1: Preparation of an aqueous topcoat composition for decorative finish films

[0066] An aqueous topcoat composition was prepared by mixing the components listed in Table 1 at room temperature. The amounts are given in weight percent, based on the total weight of the aqueous topcoat composition.

[0067] Table 1: Aqueous topcoat composition

[0068] Example 2A: Production of a decorative finish film with a color layer and a transparent primer layer

[0069] The topcoat composition prepared in Example 1 was used to produce a topcoat for a decorative finish film. For this purpose, 90 parts by weight of the aqueous topcoat composition from Example 1 were mixed with 10 parts by weight of an aqueous 10 wt. % polyisocyanate emulsion as the hardener component.

[0070] The decorative finish film was produced using an inline process on a conventional printing press with a coating unit installed at the end. Pre-impregnated decorative paper was printed with a water-based ink using rotogravure printing. A transparent primer composition was applied to the printed paper using a roller doctor. The subsequent crosslinking of the primer composition was initiated using a flotation dryer at a maximum temperature of 200°C. The mixture, made from the aqueous topcoat composition and hardener component, was applied to the treated decorative paper using a roller doctor and crosslinked in the flotation dryer at a maximum temperature of 220°C. The resulting decorative finish film was then rolled up.

[0071] Example 2B: Production of a decorative finish film with a pigmented primer layer

[0072] The topcoat composition prepared in Example 1 was used to prepare a topcoat of a decorative finish film.

[0073] For this purpose, 90 parts by weight of the aqueous topcoat composition from Example 1 were mixed with 10 parts by weight of an aqueous 10 wt.% polyisocyanate emulsion as a hardener component.

[0074] The decorative finish film was produced using an inline process on a conventional printing press with a coating unit installed at the end of the press. A pigmented primer composition was applied to pre-impregnated paper using a roller doctor blade. The subsequent crosslinking of the primer composition was initiated using a flotation dryer at a maximum temperature of 200 °C. The mixture, made from the aqueous topcoat composition and hardener component, was applied to the treated decorative paper using a roller doctor blade and crosslinked in the flotation dryer at a maximum temperature of 220 °C. The resulting decorative finish film was then rolled up.

[0075] The decorative finish film produced in Example 2A was applied to a wooden substrate using a wrapping machine. The wooden substrate subsequently exhibited the desired color impression printed on the paper, as well as the desired tactile feel. Furthermore, the surface of the wooden substrate was protected from mechanical stress such as abrasion and scratching.

[0076] In addition, the decorative finish film produced in Example 2A was applied to a wooden substrate using a laminating machine. The wooden substrate subsequently exhibited the desired color impression printed on the paper, as well as the desired haptic quality. Furthermore, the surface of the wooden substrate was protected from mechanical stress such as abrasion and scratching.

[0077] The decorative finish film produced in Example 2B was applied to a wooden substrate using a wrapping machine. The resulting wood substrate exhibited the desired uniform color impression and tactile feel. Furthermore, the surface of the wood substrate was protected from mechanical stress such as abrasion and scratching.

[0078] In addition, the decorative finish film produced in Example 2B was applied to a wooden substrate using a laminating machine. The resulting wooden substrate exhibited the desired uniform color impression and tactile feel. Furthermore, the surface of the wooden substrate was protected from mechanical stress such as abrasion and scratching.

[0079] 10

Claims

Patent claims for an aqueous topcoat composition for decorative finish films comprising, based on the total weight of the topcoat composition, 50 to 95 wt.% crosslinkable OH-functional acrylic emulsion, wherein the aqueous topcoat composition is free of formaldehyde-based compounds. An aqueous topcoat composition according to claim 1, characterized in that the aqueous topcoat composition contains, based on the total weight of the topcoat composition, 60 to 90 wt.%, in particular 70 to 85 wt.% crosslinkable OH-functional acrylic emulsion. An aqueous topcoat composition according to claim 1 or 2, characterized in that the crosslinkable OH-functional acrylic emulsion has a solids content of 20 to 70 wt.%, in particular 30 to 60 wt.% or 40 to 50 wt.%, and / or the crosslinkable OH-functional acrylic emulsion is quenched at 23 °C and a shear rate of 100 s⁻¹. _1a viscosity, determined according to standard DIN EN ISO 3219, of 5 to 500 mPas, in particular of 10 to 100 mPas or of 15 to 40 mPas, and / or the crosslinkable OH-functional acrylic emulsion has a minimum film-forming temperature of 30 to 220 °C, in particular of 35 to 100 °C or of 40 to 70 °C, and / or the crosslinkable OH-functional acrylic emulsion has a glass transition temperature of 20 to 150 °C, in particular of 30 to 110 °C or of 40 to 70 °C, and / or the crosslinkable OH-functional acrylic emulsion has a hydroxyl number, based on the solids content of the crosslinkable OH-functional acrylic emulsion, of 10 to 500 mg KOH / g, in particular of 30 to 300 mg KOH / g or of 50 to 150 mg KOH / g, and / or the crosslinkable OH-functional acrylic emulsion is an OH-functional copolymer emulsion, in particular an OH-functional acrylate-methacrylate-styrene copolymer emulsion, and / or the crosslinkable OH-functional acrylic emulsion is crosslinkable with isocyanates, in particular with polyisocyanates, and a polyurethane is formed during crosslinking.Aqueous topcoat composition according to one of the preceding claims, characterized in that the aqueous topcoat composition has a flow time at 23 °C, determined using a flow cup with a nozzle diameter of 6 mm according to standard ISO 2431, of 5 to 50 seconds, in particular of 11 to 22 seconds, and / or the aqueous topcoat composition has a pH value of 5 to 11, in particular of 6 to 10 or of 7 to 9, at 25 °C. Aqueous topcoat composition according to one of the preceding claims, characterized in that the aqueous topcoat composition has a pH of 0.1 to 50% based on the total weight of the topcoat composition. 20 wt.%, in particular 1 to 15 wt.% or 2 to 10 wt.% additives, wherein the additives are in particular wetting agents, dispersing agents, defoamers, leveling additives, rheology additives, matting agents, surface additives and / or additives to improve scratch resistance. Aqueous topcoat composition according to one of the preceding claims, characterized in that the aqueous topcoat composition, based on the total weight of the topcoat composition, comprises 0.1 to 10 wt.%, in particular 0.5 to 7.5 wt.% or 1 to 5 wt.% film-forming aids. A process for producing an aqueous topcoat composition according to any one of claims 1 to 6, comprising i. providing a crosslinkable OH-functional acrylic emulsion, water, and optionally additives and / or film-forming aids, ii. mixing the crosslinkable OH-functional acrylic emulsion, the water, and optionally the additives and / or film-forming aid in a mixing ratio such that the aqueous topcoat composition obtained by mixing contains 50 to 95 wt.% crosslinkable OH-functional acrylic emulsion, based on the total weight of the aqueous topcoat composition.A method according to claim 7, characterized in that the aqueous topcoat composition is as defined in any one of claims 1 to 6 and / or the crosslinkable OH-functional acrylic emulsion is as defined in claim 3 and / or the additives are as defined in claim 5. A kit for producing a topcoat for decorative finish films comprising a component 1 and a component 2, characterized in that component 1 is an aqueous topcoat composition according to any one of claims 1 to 6 and component 2 is an aqueous hardener component, wherein the aqueous hardener component contains isocyanate, in particular polyisocyanate.

10. Kit according to claim 9, characterized in that the aqueous hardener component contains, in each case based on the total weight of the aqueous hardener component, isocyanate, in particular polyisocyanate, in an amount of 1 to 25 wt.%, in particular of 5 to 20 wt.%, and / or the polyisocyanate has an NCO content of 5 to 30 wt.%, in particular of 10 to 20 wt.%.

11. Decorative finish film comprising a carrier material and a topcoat layer, wherein the topcoat layer is a polyurethane layer which can be produced by crosslinking an aqueous topcoat composition according to one of claims 1 to 6 with an aqueous hardener component according to one of claims 9 to 10.

12. Decorative finish film according to claim 11, characterized in that the topcoat layer is applied over the entire surface or partially to at least one side of the substrate material, and / or the topcoat layer has a basis weight of 3 to 15 mg / m² 2 , especially from 4 to 12 g / m³2 or from 5 to 11 g / m² 2 exhibits.

13. Decorative finish film according to claim 11 or 12, characterized in that the carrier material is made of plastic or paper, in particular polyethylene terephthalate, polypropylene or paper, in particular paper.

14. Decorative finish film according to one of claims 11 to 13, characterized in that the decorative finish film comprises a color layer between the carrier material and the topcoat layer, wherein the color layer contains in particular binders, in particular protein binders, in particular casein, and pigments. Decorative finish film according to claim 14, characterized in that the decorative finish film comprises a transparent primer layer between the color layer and the topcoat layer, wherein the transparent primer layer is transparent to electromagnetic waves with wavelengths from 400 nm to 780 nm, and wherein the transparent primer layer in particular contains a cross-linked polyacrylate. Decorative finish film according to any one of claims 11 to 13, characterized in that the decorative finish film comprises a pigmented primer layer between the substrate and the topcoat layer, wherein the pigmented primer layer in particular contains a cross-linked polyacrylate and pigments, and in particular wherein the pigments are contained in the pigmented primer layer in an amount of 1 to 70 wt.%, in particular 2 to 60 wt.%, or 5 to 40 wt.%, based on the total weight of the pigmented primer layer.Decorative finishing film according to one of claims 11 to 16, characterized in that the decorative finishing film has a basis weight of 25 to 100 g / m². 2 , especially from 45 to 82 g / m² 2 exhibits, and / or the decorative finish film is free of formaldehyde-based compounds. A method for producing a decorative finish film, comprising: i. providing a substrate material, an aqueous topcoat composition according to any one of claims 1 to 6, and an aqueous hardener component; ii. mixing the aqueous topcoat composition and the aqueous hardener component; iii. applying the mixture produced in step ii. to the substrate material. iv. Crosslinking of the aqueous topcoat composition and the aqueous hardener composition.

19. Method according to claim 18, characterized in that the decorative finish film is defined as in any one of claims 11 to 17 and / or the carrier material is defined as in claim 13 and / or the aqueous hardener component is defined as in any one of claims 9 to 10.

20. Method according to claim 18 or 19, characterized in that the mixing in step ii. is carried out in a mixing ratio of aqueous topcoat composition to aqueous hardener component of 20:1 to 1:1 weight parts, in particular of 15:1 to 3:1 weight parts or of 12:1 to 6:1 weight parts.

21. Method according to one of claims 18 to 20, characterized in that the crosslinking in step iv. takes place at 80 to 250 °C, in particular at 100 to 230 °C, and / or the crosslinking in step iv. takes place in a thermal dryer, in particular a suspension dryer, and / or the crosslinking in step iv. takes place without electron beam curing and without UV curing, in particular without radiation curing.

22. A method according to any one of claims 18 to 21, characterized in that the method comprises, prior to step iii, the following step: a. printing the substrate with a layer of ink, wherein the printing is carried out in particular by flexographic printing, digital printing and / or gravure printing, in particular by rotogravure printing, and / or the method comprises the following steps: b. Applying a primer composition to the substrate, in particular wherein the primer composition contains a crosslinkable polyacrylate, wherein the primer composition optionally contains pigments, c. Crosslinking the primer composition.

23. Decorative finish film obtained or obtainable by a method according to any one of claims 18 to 22.

24. Use of an aqueous topcoat composition according to any one of claims 1 to 6 or of a kit for producing a topcoat for decorative finish films according to any one of claims 9 or 10 for producing a topcoat for a decorative finish film.

25. Use of a decorative finish film according to one of claims 11 to 17 or 23 for coating wooden supports, edges and / or furniture, in particular shelves.

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