System comprising a sponge and a coating agent

Abstract

The invention relates to a system for coating manufactured wood products, comprising a sponge and a coating agent, wherein the sponge has an average pore size of 0.08 mm to 1 mm and / or a pore density of 1 to 1000 pores / mm3, as well as to the use of the system for coating a manufactured wood product and to a method for coating manufactured wood products.

Description

[0001] The invention relates to a system for coating wood-based materials, the use of the system for coating wood-based materials and a method for coating wood-based materials.

[0002] Wood-based materials, especially those intended for outdoor storage, require a protective coating. Often, preserving the wood grain is desirable, necessitating thin coatings. Wood stains are particularly suitable for this purpose.

[0003] Tools for applying coatings, especially varnishes, to wood-based materials are well-known. Most commonly, brushes or paint rollers are used. Brushes have the disadvantage that surfaces coated with them often have an undesirable, inhomogeneous, and especially streaky appearance. Furthermore, it is difficult to control the amount of material applied with brushes, which limits the coverage of the coating, especially the varnish. Finally, brushes tend to splash when applying coatings, especially varnishes, so the area around the wood-based material must be covered for protection. Achieving a homogeneous surface finish is also difficult with paint rollers. Paint rollers also tend to splash. Additionally, paint rollers have the disadvantage of introducing a significant amount of air into the coating during application.Furthermore, it is difficult to coat paneling, such as tongue and groove boards, with paint rollers.

[0004] The use of brushes and sponges for applying stains or varnishes to wooden panels is known, for example, from DE 24 54 343 A1. However, DE 24 54 343 A1 describes the sponge only as an alternative to a brush or spraying and does not elaborate on the properties of the sponge or any potential advantages.

[0005] US 6,294,021 B1 describes a system for applying fast-drying coating compositions, the system comprising a plastic container with a pressure relief valve containing the coating composition, a sponge with a flat application surface and a pore structure connected by capillaries and open at the application surface, the sponge embedding the pressure relief valve, and a lid for airtight sealing of the sponge when the system is not in use.

[0006] US 2012 / 0141688 A1 describes a release agent applicator comprising a foam structure consisting of a plurality of cells, wherein the cells are defined by a wall with at least one opening through which the release agent can pass.

[0007] FR 2 928 075 A3 describes a roller cover with a cylindrical tube shape made of cellulose sponge material.

[0008] During the applicant's trials on applying coatings, especially varnishes, to wood-based materials, it was found that not all sponges are suitable for applying coatings, especially varnishes.

[0009] The object of the invention was therefore to provide a system for coating wood-based materials that at least partially overcomes one or more of the disadvantages of the prior art. In particular, the application process should be as fast as possible. Furthermore, the system should exhibit a low tendency to spatter. Additionally, the system should allow for a homogeneous surface finish. Finally, the system should enable a low material application rate in order to ensure high area coverage.

[0010] This problem is solved by a system according to claim 1, a use according to claim 13 and a method according to claim 14.

[0011] Advantageous embodiments of the invention are specified in the dependent claims and are explained in more detail below.

[0012] The invention provides a system for coating wood-based materials comprising a sponge and a coating agent, wherein the sponge has a mean pore size of 0.08 mm to 1 mm and / or a pore density of 1 to 1000 pores / mm³, wherein the coating agent has a viscosity of 50000 to 3000 mPa·s at a shear rate of 0 to 1 s⁻¹, a viscosity of 10000 to 500 mPa·s at a shear rate of 1.01 to 100 s⁻¹, and a viscosity of 5000 to 50 mPa·s at a shear rate of 100.01 to 1000 s⁻¹, and wherein the viscosity is determined using a Bohlin Gemini rheometer from Malvern at a temperature of 23 °C and a cone geometry with a diameter of 40 mm and an inclination of 4° is used.

[0013] The applicant's experiments revealed that systems comprising coating materials and sponges with a mean pore size of 0.08 mm to 1 mm and / or a pore density of 1 to 1000 pores / mm³ allow for the rapid application of a coating material to surfaces, particularly wood-based materials. Only minimal spattering was observed. Furthermore, the material application rate can be kept low, resulting in high coverage.

[0014] Surprisingly, it has been found that the average pore size and / or pore density of the sponge have a significant influence on the application behavior of the system. For example, it is virtually impossible to achieve a uniform surface finish with sponges having an average pore size greater than 1 mm and / or a pore density of less than 1 pore / mm³. If the sponge had an average pore size of less than 0.08 mm and / or a pore density greater than 1000 pores / mm³, it either did not absorb enough coating material or released it inadequately to the surface to be coated. Both of these effects, outside the range of 0.08 mm to 1 mm for the average pore size and / or 1 to 1000 pores / mm³ for the pore density, were contrary to the expectations of a person skilled in the art.

[0015] When the term "coating" is used here or elsewhere, it refers specifically to the application of a coating material to a substrate. The coating material does not necessarily have to form a separate layer on the surface, but can also penetrate the substrate at least partially or completely.

[0016] The mean pore size refers specifically to the mean diameter of the pores. To determine the mean diameter, the pores can be approximated as spheres with an equivalent volume. Methods for determining the mean pore size are known to those skilled in the art. For example, the mean pore size can be determined by measuring the diameter of a large number of pores in microscopic images and calculating the average. Furthermore, the mean pore size can also be determined using micro-computed tomography.

[0017] The term "wood-based materials" as used in this invention specifically includes wood plastic composites.

[0018] The sponge of the system according to the invention has a mean pore size of 0.08 mm to 1 mm and / or a pore density of 1 to 1000 pores / mm³. In particular, the sponge can have a mean pore size of 0.1 mm to 0.7 mm, 0.125 mm to 0.6 mm, 0.15 mm to 0.5 mm, 0.175 mm to 0.45 mm, or 0.2 mm to 0.4 mm. The pore density of the sponge of the system according to the invention can in particular be 3 to 900 pores / mm³, 5 to 500 pores / mm³, 8 to 300 pores / mm³, 10 to 200 pores / mm³, 13 to 150 pores / mm³, or 15 to 125 pores / mm³. Sponges with the aforementioned medium pore sizes and / or pore densities can produce particularly homogeneous surfaces, while simultaneously ensuring good application of the coating material to the surface.

[0019] The pores of the sponge in the system according to the invention are preferably open. This allows the sponge to absorb and release the coating agent effectively.

[0020] The sponge of the system according to the invention can in particular have a mean pore size of 0.08 mm to 1 mm, in particular of 0.1 mm to 0.7 mm, of 0.125 mm to 0.6 mm, of 0.15 mm to 0.5 mm, of 0.175 mm to 0.45 mm or of 0.2 mm to 0.4 mm and a pore density of 1 to 1000 pores / mm³, in particular of 3 to 900 pores / mm³, 5 to 500 pores / mm³, 8 to 300 pores / mm³, 10 to 200 pores / mm³, 13 to 150 pores / mm³ or 15 to 125 pores / mm³. Particularly good results were achieved with such sponges with regard to the homogeneity of the coated surface as well as the absorption and release of the coating agent.

[0021] The sponge of the system according to the invention can furthermore have a compression hardness of 0.0001 to 0.05 N / mm², in particular of 0.0005 to 0.01 N / mm², 0.001 to 0.009 N / mm², 0.002 to 0.008 N / mm², 0.002 to 0.007 N / mm², 0.003 to 0.006 N / mm² or of 0.004 to 0.0055 N / mm², wherein the compression hardness is determined according to DIN EN ISO 3386-1, in particular according to DIN EN ISO 3386-1:2015-10. A greater tendency to splash was observed with a compression hardness of the sponge of more than 0.05 N / mm². If the compression hardness of the sponge was less than 0.0001 N / mm², the area coverage of a coating material to be applied was reduced.

[0022] The sponge material of the system according to the invention can be selected from the group consisting of polyurethane, polyester urethane, polyester, polyether, polystyrene, polyethylene, polypropylene, rubber, synthetic rubber, nitrile rubber, and ethylene-propylene copolymer rubber. Sponges made of such materials have proven to be durable. According to a preferred embodiment of the invention, the sponge of the system according to the invention contains or consists of polyurethane.

[0023] The sponge of the system according to the invention can be homogeneous. Specifically, the sponge of the system according to the invention can be homogeneous with respect to the mean pore size, pore density, density, compression hardness, and / or material. Accordingly, a sponge of the system according to the invention can have a substantially uniform mean pore size, pore density, and / or compression hardness within the volume defined by the sponge. Furthermore, the entire volume of the sponge can accordingly consist of the same material.

[0024] The sponge of the system according to the invention is, in particular, free of holding devices. Furthermore, the sponge of the system according to the invention can be made in one piece. This ensures, in particular, direct force transmission. The sponge can have any shape. In particular, the sponge can have the shape of a cuboid. According to a particularly preferred embodiment of the invention, the sponge has the shape of a cuboid with a wedge attached to one side of the cuboid, in particular to an end face of the cuboid. With such a sponge, even surfaces that have narrow crevices and / or corners or that require high precision in coating can be coated effectively. To facilitate handling, the sponge can have one or more finger grips or a groove on at least one of its side surfaces.Furthermore, the sponge can have a chamfer, in particular a chamfer of 20° to 70°, and / or a radius, in particular a radius of at least 2 mm, on at least one of its edges. The presence of a radius or chamfer on the top surface of the sponge facilitates the effective coating of corners of a surface to be coated. The sponge can, in particular, be symmetrical about a plane passing through the wedge tip and the center of the opposite surface. This makes the sponge suitable for use by both right- and left-handed users. Moreover, due to its symmetry, the sponge can be manufactured with less material waste.

[0025] Various coating materials are suitable as coating materials for the system according to the invention. In particular, the coating material can be a shear-thinning coating material.

[0026] Structure-viscosity coating materials are known to those skilled in the art. Those skilled in the art understand structure-viscosity coating materials to be, in particular, coating materials that exhibit decreasing viscosity with increasing shear forces.

[0027] In particular, the system according to the invention can comprise a sponge with a mean pore size of 0.08 mm to 1 mm, of 0.1 mm to 0.7 mm, of 0.125 mm to 0.6 mm, of 0.15 mm to 0.5 mm, of 0.175 mm to 0.45 mm or of 0.2 mm to 0.4 mm and / or a pore density of 1 to 1000 pores / mm³, in particular of 3 to 900 pores / mm³, 5 to 500 pores / mm³, 8 to 300 pores / mm³, 10 to 200 pores / mm³, 13 to 150 pores / mm³ or 15 to 125 pores / mm³ and a viscous coating agent.

[0028] Surprisingly, the combination of a sponge with a pore size of 0.08 mm to 1 mm and / or a pore density of 1 to 1000 pores / mm³ with a viscous coating material has yielded particularly good results in coating wood-based materials. In particular, such systems have enabled the creation of surfaces with a homogeneous finish in a short time. Without adhering to a scientific theory, this surprising effect seems to be explained by the fact that, given the specified pore size and / or pore density of the sponge, a viscous coating material can penetrate the pores effectively and be retained just enough to minimize dripping and / or splashing, while simultaneously being dispensed in a quantity that ensures a uniform and sufficient application, thus providing high coverage.This effect was unforeseeable for the expert.

[0029] This effect can be further enhanced if the sponge of the system according to the invention also has a compression hardness of 0.0001 to 0.05 N / mm², in particular of 0.0005 to 0.01 N / mm², 0.001 to 0.009 N / mm², 0.002 to 0.008 N / mm², 0.002 to 0.007 N / mm², 0.003 to 0.006 N / mm² or of 0.004 to 0.0055 N / mm², wherein the compression hardness is determined by means of DIN EN ISO 3386-1, in particular according to DIN EN ISO 3386-1:2015-10.

[0030] In particular, the coating material of the system according to the invention can have a viscosity of 20,000 to 3,500 mPa·s at a shear rate of 0 to 1 s⁻¹, a viscosity of 7,000 to 800 mPa·s at a shear rate of 1.01 to 100 s⁻¹, and a viscosity of 3,500 to 100 mPa·s at a shear rate of 100.01 to 1,000 s⁻¹. Furthermore, the coating material can have a viscosity of 10,000 to 4,000 mPa·s at a shear rate of 0 to 1 s⁻¹, a viscosity of 5,000 to 900 mPa·s at a shear rate of 1.01 to 100 s⁻¹, and a viscosity of 2,500 to 150 mPa·s at a shear rate of 100.01 to 1,000 s⁻¹. Systems using such coating materials exhibited a very low tendency to spatter, even when applied quickly to the surface.

[0031] The viscosity is determined using a Malvern Bohlin Gemini rheometer at a temperature of 23°C. A cone geometry with a diameter of 40 mm and an inclination of 4° is used.

[0032] The coating material of the system according to the invention can furthermore have a solids content of 15 to 50 wt.%, based on the total weight of the coating material.

[0033] The coating material of the system according to the invention comprises, in each case based on the total weight of the coating material, preferably 10 to 45 wt.%, in particular 15 to 30 wt.% or 20 to 25 wt.%, polymer, 0.01 to 3 wt.%, in particular 0.1 to 2.5 wt.%, 0.5 to 2 wt.% or 1 to 1.5 wt.%, pigment, 0.1 to 10 wt.%, in particular 0.5 to 8 wt.%, 1 to 7 wt.%, 2 to 5 wt.% or 3 to 4 wt.%, thickener, 0.1 to 10 wt.%, additives, 45 to 85 wt.%, in particular 50 to 80 wt.%, 55 to 75 wt.% or 60 to 70 wt.%, water.

[0034] Various polymers are suitable as the polymer of the coating agent of the system according to the invention. Preferably, the polymer of the coating agent contains at least one alkyd resin and / or at least one polyurethane and / or at least one polymer and / or copolymer based on at least one monomer selected from the group consisting of acrylic acid, acrylic acid derivatives, acrylic acid esters, methacrylic acid, methacrylic acid derivatives, methacrylic acid esters, styrene, styrene derivatives, N-vinylpyrrolidone, acrylonitrile, vinyl acetate, vinyl propionate, ethylene unsaturated carboxylic acids, ethylene unsaturated carboxylic acid esters, ethylene unsaturated carboxylic acid anhydrides, ethylene unsaturated carboxylic acid amides, and carboxylic acid vinyl esters. Particularly preferably, the polymer of the coating agent contains at least one polymer based on acrylic acid derivatives and / or styrene.When using acrylic acid esters and / or methacrylic acid esters, it is preferred that the alcohol residue contains 1 to 12 carbon atoms. The alcohol residue may furthermore be branched or unbranched. According to a preferred embodiment, the polymer of the coating material consists of at least one of the aforementioned polymers and / or copolymers. According to a further embodiment, the polymer of the coating material contains or consists of at least one alkyd resin. According to a further embodiment, the polymer of the coating material contains or consists of at least one polyurethane.

[0035] Various substances are suitable as pigments. The preferred pigment is selected from the group consisting of titanium dioxide, iron oxide yellow, arylide (monoazo), bismuth vanadate, perinone, rutile tin-zinc, quinacridone, diketo-pyrrolo-pyrrole, iron oxide red, phthalocyanine blue, dioxazine, cobalt blue, ultramarine blue, phthalocyanine green, chromium oxide green, cobalt green, carbon black, iron oxide black, pyrazolo-quinazolone, naphthol-AS monoazo pigment, and mixtures thereof.

[0036] According to one embodiment, inorganic pigments are preferably used. Examples of inorganic pigments are oxides such as titanium dioxide, iron oxides, e.g., PY 42, PR 101, P.Bk. 11, chromium oxide green, e.g., PG 17, mixed-phase pigments, e.g., cobalt oxides blue PB 28 and green PG 50, bismuth vanadate PY 184, rutile tin-zinc PO 216, silicates, e.g., ultramarine blue PB 29, and carbon, e.g., carbon black P.Bk. 7.

[0037] According to another embodiment, organic pigments are preferably used. Examples of organic pigments are azo pigments, e.g., arylide yellow (monoazo) PY 74; polycyclic pigments, e.g., quinacridone PR 122, perinone PO 43, pyrazoloquinazolone PO 67, diketo-pyrrolo-pyrrole (DPP) PR 254, dioxazines PV 23; and metal complex pigments, e.g., copper phthalocyanines blue PB 15:3 and green PG 7.

[0038] The names of the inorganic and organic pigments used for the examples correspond to the Generic Names of the Colour Index of the British Society of Dyers and Colourists.

[0039] According to another embodiment, mixtures of inorganic and organic pigments are used.

[0040] Suitable thickeners include, for example, polyurethane-based, cellulose-based, acrylate-based, and / or bentonite-based thickeners, preferably polyurethane-based. Examples of additives include defoamers, wetting agents, preservatives, and surface protectants.

[0041] Furthermore, coating materials may also contain solvents, in particular from 1 to 10 wt.%, based on the total weight of the coating material, to allow a longer open time.

[0042] In particular, the coating material of the system according to the invention can be a glaze.

[0043] The term "glaze" refers specifically to non-opaque coating materials. Examples of glazes include wood stains.

[0044] The invention further relates to the use of a system according to the invention for coating a wood-based material.

[0045] The invention further relates to a method for coating a wood-based material. i. Providing a system comprising a sponge and a coating agent, wherein the sponge has a mean pore size of 0.08 mm to 1 mm and / or a pore density of 1 to 1000 pores / mm³, wherein the coating agent has a viscosity of 50,000 to 3,000 mPa·s at a shear rate of 0 to 1 s⁻¹, a viscosity of 10,000 to 500 mPa·s at a shear rate of 1.01 to 100 s⁻¹, and a viscosity of 5,000 to 50 mPa·s at a shear rate of 100.01 to 1,000 s⁻¹, wherein the viscosity is determined using a Malvern Bohlin Gemini rheometer at a temperature of 23 °C and a cone geometry with a diameter of 40 mm and an inclination of 4° is used; ii. The coating is applied by wiping the sponge containing the coating agent over the surface of the wood material.

[0046] The above statements regarding the system according to the invention apply analogously to the sponge of the inventive method and to the coating agent of the inventive method.

[0047] The invention is explained in more detail below with reference to drawings illustrating only preferred embodiments. Fig. 1 shows a first embodiment of a sponge according to the invention in perspective view, and Fig. 2 shows a second embodiment of a sponge according to the invention in perspective view.

[0048] Fig. 1 Figure 1 shows a first preferred embodiment of the sponge 1 according to the invention, as it can also be used in the system according to the invention. Due to its cuboid shape with a wedge attached to one side, even surfaces with narrow crevices and / or corners, or which require high precision in coating, can be coated effectively. Fig. 1The edges on the top surface of the sponge 1 have a radius 2, in particular of at least 3 mm. Alternatively, the edges of the top surface of the sponge 1 can also have a chamfer, in particular of 20° to 70°, or have neither a radius nor a chamfer. The presence of a radius or a chamfer on the top surface of the sponge 1 makes it easier to effectively coat corners of a surface to be coated. The sponge 1 can, as in Figure 1 The sponge 1 is shown to be symmetrical about a plane passing through the wedge tip and the center of the opposite surface. This makes the sponge 1 suitable for use by both right- and left-handed people. Furthermore, due to its symmetry, the sponge 1 can be manufactured with less material waste. Additionally, the sponge 1 has a porous structure 3, which is shown schematically enlarged in the figure. Fig. 1 is reproduced.

[0049] Fig. 2Figure 1 shows a second preferred embodiment of sponge 11 according to the invention, as it can also be used in the system according to the invention. Sponge 11 is essentially identical to sponge 1. Fig. 1 Identical parts are provided with identical reference numerals. In particular, sponge 11 differs from sponge 1 in that sponge 11 has two sides 12a and 12b, which are designed as gripping surfaces. This can be seen, as in Fig. 2 This is indicated by radii 14 arranged on opposite sides where the wedge is not attached. Alternatively, these gripping surfaces can also be convex. Such a design facilitates gripping and holding the sponge.

[0050] The principle of the invention will be explained in more detail below using examples. Examples of implementation materials

[0051] Glaze 1 Aqueous glaze with a viscosity of 6800 mPa·s at 0.01 s⁻¹, 5000 mPa·s at 0.1 s⁻¹, 4400 mPa·s at 1 s⁻¹, 4400 mPa·s at 10 s⁻¹, 1100 mPa·s at 100 s⁻¹, and 220 mPa·s at 1000 s⁻¹ Sponge A Polyurethane sponge with a mean pore size of 0.2 to 0.4 mm and a compression hardness of 0.005 N / mm² Brush 1 70 mm glaze brush (synthetic fiber) Sponge B Polyurethane sponge with a mean pore size of 0.04 mm to 0.05 mm and a compression hardness of 0.009 N / mm² Sponge C Polyurethane sponge with a mean pore size of 1.5 to 2.0 mm and a compression hardness of 0.001 N / mm² Glaze 2 Aqueous glaze with a viscosity of 2200 mPa·s at 0.01 s⁻¹, 1900 mPa·s at 0.1 s⁻¹, 1600 mPa·s at 1 s⁻¹, 1300 mPa·s at 10 s⁻¹, 900 mPa·s at 100 s⁻¹, and 600 mPa·s at 1000 s⁻¹

[0052] The viscosities of glazes 1 and 2 were determined using a Bohlin Gemini 150 rheometer from Malvern at a temperature of 23°C using a cone geometry (diameter 40 mm, inclination 4°). Example 1 (comparison of applying glaze with a sponge versus a brush)

[0053] Pine garden stools were coated with stain 1. Two different test subjects used both sponge A and, for comparison, brush 1. The application time, the amount of stain applied (in g / m²), and the tendency to spatter were measured and compared. The results are summarized in Table 1. Table 1: Results of the comparative test of applying the glaze with a sponge or with a brush Subject 1 Subject 2 Application tool Sponge A Brush 1 Sponge A Brush 1 Painting time [s] 90 158 148 202 Material application [g / m²< ] 45 47 33 57 Splash tendency Few Much Few Much

[0054] Table 1 shows that sponge A allows for a shorter application time with less splashing compared to brush 1. Simultaneously, significantly less material is applied with sponge A compared to brush 1, thus considerably increasing the coverage of the glaze. Furthermore, the garden stools coated with sponge A exhibited a homogeneous surface finish, while those coated with a brush showed a partially streaked appearance. Example 2 (comparative example)

[0055] A pine garden stool was coated with stain 1 using sponge B. It was found that the sponge did not apply the stain sufficiently to the surface of the stool. Consequently, the coating process took a very long time. Example 3 (comparative example)

[0056] A pine garden stool was coated with stain 1 using sponge C. The coated garden stool had a mottled surface finish. Example 4 (comparative example)

[0057] A pine garden stool was coated with stain 2 using sponge A. A strong tendency to splash and drip was observed.

Claims

1. System for coating wood-based materials, the system comprising a sponge (1, 11) and a coating agent, the sponge (1, 11) having an average pore size of 0.08 mm to 1 mm, and / or a pore density of 1 to 1000 pores / mm3, characterized in that at a shear rate of 0 to 1 s-1 the coating agent has a viscosity of 50000 to 3000 mPa·s, and at a shear rate of 1.01 to 100 s-1 the coating agent has a viscosity of 10000 to 500 mPa·s, and at a shear rate of 100.01 to 1000 s-1 the coating agent has a viscosity of 5000 to 50 mPa·s, the viscosity being determined using a Bohlin Gemini rheometer from the company Malvern at a temperature of 23°C, and a cone geometry having a diameter of 40 mm and an inclination of 4° being used.

2. System according to claim 1, characterized in that the sponge (1, 11) has an average pore size of 0.1 mm to 0.7 mm, in particular of 0.125 mm to 0.6 mm, of 0.15 mm to 0.5 mm, of 0.175 mm to 0.45 mm, or of 0.2 mm to 0.4 mm.

3. System according to claim 1 or 2, characterized in that the sponge (1, 11) has a pore density of 3 to 900 pores / mm3, in particular of 5 to 500 pores / mm3, 8 to 300 pores / mm3 10 to 200 pores / mm3, 13 to 150 pores / mm3, or 15 to 125 pores / mm3.

4. System according to any of the preceding claims, characterized in that the sponge (1, 11) has a compression hardness of 0.0001 to 0.05 N / mm2, in particular of 0.0005 to 0.01 N / mm2, 0.001 to 0.009 N / mm2, 0.002 to 0.008 N / mm2, 0.002 to 0.007 N / mm2, 0.003 to 0.006 N / mm2, or of 0.004 to 0.0055 N / mm2, the compression hardness being determined according to DIN EN ISO 3386-1, in particular according to DIN EN ISO 3386-1:2015-10.

5. System according to any of the preceding claims, characterized in that the material of the sponge (1, 11) is selected from the group consisting of polyurethane, polyester urethane, polyester, polyether, polystyrene, polyethylene, polypropylene, rubber, synthetic rubber, nitrile rubber, and ethylene-propylene copolymer rubber, in particular polyurethane.

6. System according to any of the preceding claims, characterized in that the sponge (1, 11) is homogeneous, in particular with respect to the average pore size, pore density, density, compression hardness, and / or material.

7. System according to any of the preceding claims, characterized in that the sponge (1, 11) is free of holding devices, and / or the sponge (1, 11) is in one piece.

8. System according to any of the preceding claims, characterized in that the coating agent is a shear thinning coating agent.

9. System according to any of the preceding claims, characterized in that at a shear rate of 0 to 1 s-1 the coating agent has a viscosity of 20000 to 3500 mPa·s, and at a shear rate of 1.01 to 100 s-1 the coating agent has a viscosity of 7000 to 800 mPa·s, and at a shear rate of 100.01 to 1000 s-1 the coating agent has a viscosity of 3500 to 100 mPa·s, or at a shear rate of 0 to 1 s-1 the coating agent has a viscosity of 10000 to 4000 mPa·s, and at a shear rate of 1.01 to 100 s-1 the coating agent a viscosity of 5000 to 900 mPa·s, and at a shear rate of 100.01 to 1000 s-1 the coating agent has a viscosity of 2500 to 150 mPa·s, the viscosity being determined using a Bohlin Gemini rheometer from the company Malvern at a temperature of 23°C, and a cone geometry having a diameter of 40 mm and an inclination of 4° being used.

10. System according to any of the preceding claims, characterized in that the coating agent has a solids content of 15 to 50 wt.%, based on the total weight of the coating agent.

11. System according to any of the preceding claims, characterized in that the coating agent comprises, in each case based on the total weight of the coating agent, • 10 to 45 wt.%, in particular 15 to 30 wt.%, or 20 to 25 wt.% polymer, • 0.01 to 3 wt.%, in particular 0.1 to 2.5 wt.%, 0.5 to 2 wt.%, or 1 to 1.5 wt.% pigment, • 0.1 to 10 wt.%, in particular 0.5 to 8 wt.%, 1 to 7 wt.%, 2 to 5 wt.%, or 3 to 4 wt.% thickener, • 0.1 to 10 wt.% additives, • 45 to 85 wt.%, in particular 50 to 80 wt.%, 55 to 75 wt.%, or 60 to 70 wt.% water.

12. System according to any of the preceding claims, characterized in that the coating agent is a glaze.

13. Use of a system according to any of the preceding claims for coating a wood-based material.

14. Method for coating a wood-based material, the method comprising i. providing a system comprising a sponge (1, 11) and a coating agent, the sponge (1, 11) having an average pore size of 0.08 mm to 1 mm, and / or a pore density of 1 to 1000 pores / mm3, characterized in that at a shear rate of 0 to 1 s-1 the coating agent has a viscosity of 50000 to 3000 mPa·s, and at a shear rate of 1.01 to 100 s-1 the coating agent has a viscosity of 10000 to 500 mPa·s, and at a shear rate of 100.01 to 1000 s-1 the coating agent has a viscosity of 5000 to 50 mPa·s, the viscosity being determined using a Bohlin Gemini rheometer from the company Malvern at a temperature of 23°C, and a cone geometry having a diameter of 40 mm and an inclination of 4° being used, ii. applying the coating by wiping the sponge (1, 11) containing the coating agent over the surface of the wood-based material.

15. Method according to claim 14, characterized in that the sponge (1, 11) is defined as in any of claims 2 to 7, and / or the coating material is characterized as in any of claims 8 to 12.

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