阅读说明：本技术 在线涂覆的装饰性木基板 (In-line coated decorative wood substrate ) 是由 C·施鲁尔 T·奥齐哈尔 于 2018-04-04 设计创作，主要内容包括：本发明涉及一种制造装饰性木基板的方法、一种装饰性木基板、包含至少一种无机颗粒状填料材料和至少一种粘结剂的至少一种干燥或液体涂料组合物用于在线涂覆装饰性木基板的用途、以及包含至少一种无机颗粒状填料材料和至少一种粘结剂的至少一种干燥或液体涂料组合物用于改善装饰性木基板的机械性能的用途。此外,本发明还涉及装饰性木基板在地板应用、家具、墙壁、屋顶板、展示柜、存储单元、扬声器及商店配件中的用途。(The present invention relates to a method of manufacturing a decorative wood substrate, the use of at least one dry or liquid coating composition comprising at least one inorganic particulate filler material and at least one binder for coating a decorative wood substrate on-line, and the use of at least one dry or liquid coating composition comprising at least one inorganic particulate filler material and at least one binder for improving the mechanical properties of a decorative wood substrate. Furthermore, the invention relates to the use of the decorative wood-based panel in flooring applications, furniture, walls, roof panels, display cases, storage units, loudspeakers and shop accessories.)

1. A method of manufacturing a decorative wood-based board, comprising the steps of:

a) Providing wood particles and/or fibres in dry form or in the form of an aqueous suspension,

b) Providing at least one dry or liquid coating composition comprising at least one inorganic particulate filler material and at least one binder,

c) Forming a wood based mat having a first side and an opposite side from the wood particles and/or fibres provided in step a),

d) Prepressing the wood-based mat of step c) into a prepressed wood-based mat,

e) Applying at least one layer of the at least one dry or liquid coating composition of step b) onto a first and/or opposite side of the pre-pressed wood based mat obtained in step d),

f) Hot-pressing the pre-pressed wood-based mat obtained in step e) into a solid wood-based board,

g) Applying at least one decorative finish onto the first and/or reverse side of the wood substrate obtained in step f) by inkjet printing, by rotogravure printing, by applying decorative paper, decorative foil or a liquid coating.

2. The process according to claim 1, wherein the wood particles and/or fibres of step a) are combined simultaneously or separately in any order with at least one base binder and/or at least one additive, preferably the at least one base binder is selected from the group consisting of phenol-formaldehyde resin (PF), urea-formaldehyde resin (UF), melamine-formaldehyde resin (MF), melamine-urea-formaldehyde resin (MUF), urea-melamine-formaldehyde resin (UMF), urea-melamine-phenol resin (UMPF), epoxy resin, methylene diphenyl diisocyanate resin (MDI), polyurethane resin (PU), resorcinol resin, starch or carboxymethyl cellulose and mixtures thereof, and/or the at least one additive is selected from the group consisting of waxes, colorants, fillers, dispersants, biocides, esters, Hardeners, flame retardants and mixtures thereof.

3. The process according to any one of claims 1 or 2, wherein the wood particles of step a) are wood chips.

4. Process according to any one of claims 1 to 3, wherein the at least one inorganic particulate filler material of step b) is selected from dolomite, Ground Calcium Carbonate (GCC), preferably Ground Calcium Carbonate (GCC) selected from marble, chalk, limestone and mixtures thereof, Precipitated Calcium Carbonate (PCC), preferably Precipitated Calcium Carbonate (PCC) selected from one or more of the aragonite, vaterite and calcite mineralogical crystal modifications, Modified Calcium Carbonate (MCC), magnesium hydroxide, talc, gypsum, titanium dioxide, kaolin, silicates, mica, barium sulfate, calcined clays, uncalcined (hydrous) clays, bentonite, inorganic pigments and mixtures thereof.

5. the process according to any one of claims 1 to 4, wherein the at least one inorganic particulate filler material of step b) is at least one inorganic particulate calcium carbonate-comprising material having a median particle size d50 of from 0.1 μm to 150.0 μm, more preferably from 0.2 μm to 100.0 μm and most preferably from 0.3 μm to 50.0 μm and/or having a specific surface area as measured by the BET nitrogen method of from 0.5 to 200.0m2/g, more preferably from 0.5 to 100.0m2/g and most preferably from 0.5 to 75.0m 2/g.

6. the process according to any one of claims 1 to 5, wherein the at least one binder of step b) is selected from alkyd resins, epoxy ester resins, poly (vinyl alcohol), poly (vinylpyrrolidone), poly (vinyl acetate), poly (oxazoline), poly (vinylacetamide), partially hydrolyzed poly (vinyl acetate/vinyl alcohol), poly ((meth) acrylic acid), poly ((meth) acrylamide), poly (alkylene oxides), polyethers, saturated polyesters, sulfonated or phosphated polyesters and polystyrenes, poly (styrene-co- (meth) acrylates), poly (styrene-co-butadiene), polyurethane latexes, poly (n-butyl (meth) acrylate), poly (2-ethylhexyl (meth) acrylate), (meth) acrylates such as copolymers of n-butyl (meth) acrylate and ethyl (meth) acrylate, poly (meth) acrylates, poly (2-ethylhexyl (, Copolymers of vinyl acetate and n-butyl (meth) acrylate, casein, copolymers of polyvinyl chloride, gelatin, cellulose ethers, zeatin, albumin, chitin, chitosan, dextran, pectin, collagen derivatives, collodion, agar-agar, arrowroot, guar gum, carrageenan, starch, tragacanth, xanthan or rhamsan, and mixtures thereof.

7. The method according to any one of claims 1 to 6, wherein the at least one dry or liquid coating composition of step b) comprises the at least one inorganic particulate filler material in an amount of 60-98% by weight, preferably 70-98% by weight and most preferably 80-98% by weight, and the at least one binder in an amount of 2-40% by weight, preferably 2-30% by weight and most preferably 2-20% by weight, based on the total dry weight of the at least one coating composition.

8. a method according to any one of claims 1 to 7, wherein in step c) a single-or multi-layer wood based mat is formed.

9. The process according to any one of claims 1 to 8, wherein the pre-pressing step d) is carried out at ambient temperature, such as 10-60 ℃, more preferably 15-30 ℃, and/or at a pressure in the range of 5-40 bar, preferably 8-35 bar.

10. The method according to any one of claims 1 to 9, wherein the coating step e) is performed by metered size press, curtain coating, spray coating or roll coating.

11. The method according to any one of claims 1 to 10, wherein the coating step e) is performed on a first and an opposite side of the pre-pressed wood based mat to produce a decorative wood based board coated on the first and opposite side, and/or the coating step e) is performed a second time using a different or the same liquid coating composition of step b).

12. The process according to any one of claims 1 to 11, wherein the hot pressing step f) is carried out at a temperature in the range of 130 ℃ and 260 ℃, more preferably 160 ℃ and 240 ℃.

13. The method according to any one of claims 1 to 12, wherein the decorative wood substrate is a fiberboard product, preferably a High Density Fiber (HDF) board, a Medium Density Fiber (MDF) board, a Low Density Fiber (LDF) board, a particle board, an Oriented Strand Board (OSB), a hardboard or a thermal insulation board.

14. The method according to any one of claims 1 to 13, wherein in step g) the at least one decorative finish is applied in the form of a liquid coating as a lacquer layer.

15. The method according to any one of claims 1 to 14, wherein the method comprises the further steps of:

h) Applying at least one protective layer to the at least one decorative finish obtained in step g), and/or

i) In case the at least one decorative finish is present on only one side, at least one backing layer, preferably in the form of paper, is applied on the side of the decorative wood substrate opposite the at least one decorative finish.

16. A decorative wood substrate comprising

a) A substrate of wood particles and/or fibres as defined in any one of claims 1 to 3,

b) At least one coating on the first and/or reverse side of the solid wood substrate, wherein the coating comprises

i) At least one inorganic particulate filler material as defined in one of claims 1, 4, 5 or 7, having a ratio [ d80/d20] of the particle size d80 to the particle size d20 of from 0.5 to 1.0, and

ii) at least one binder as defined in one of claims 1, 6 or 7,

c) At least one decorative finish on the first and/or reverse side of the wood-based board.

17. The decorative wood substrate according to claim 16, wherein the at least one decorative finish is present on at least one coating on the first and/or opposite side of the wood substrate.

18. the decorative wood substrate according to claim 16 or 17, wherein the at least one decorative finish is present on one side of the wood substrate and the at least one coating layer is present on the opposite side of the wood substrate and represents or is part of a backing layer.

19. The decorative wood substrate according to any one of claims 16 to 18, wherein the at least one inorganic particulate filler material has

i) < particle size d98 of 500 μm,

ii) a particle size d80 of 0.1 to 250 μm,

iii) a median particle size d50 of from 0.1 to 150 μm, and

iv) a particle size d20 of 0.1 to 50 μm.

20. The decorative wood substrate according to any one of claims 16 to 19, wherein the surface of the coated side of the decorative wood substrate has

i) 50-100% brightness according to ISO R457(Tappi452) and DIN 6167,

ii) a yellowness of 2 to 70% according to ISO R457(Tappi452) and DIN 6167,

iii) according to DIN EN ISO 11664-4:2012 from 50 to 100 x,

iv) according to DIN EN ISO 11664-4: 2012-5 to 10 a, and

v) according to DIN EN ISO 11664-4:2012 b from 0 to 30.

21. The decorative wood substrate according to any one of claims 16 to 20, wherein at least one coated surface of the decorative wood substrate has

i) A maximum roughness amplitude Sz of 20-800 μm,

ii) an arithmetic average roughness Sa of 2 to 80 μm, and

iii) a root mean square roughness Sq of 2-20 μm.

22. The decorative wood substrate according to any one of claims 16 to 21, wherein the at least one inorganic particulate filler material has

i) < particle size d98 of 500 μm,

ii) a particle size d80 of 0.1 to 250 μm,

iii) a median particle size d50 of from 0.1 to 150 μm, and

iv) a particle size d20 of 0.1 to 50 μm,

And the surface of the coated side of the decorative wood substrate has

i) 50-100% brightness according to ISO R457(Tappi452) and DIN 6167,

ii) a yellowness of 2 to 70% according to ISO R457(Tappi452) and DIN 6167,

iii) according to DIN EN ISO 11664-4:2012 from 50 to 100 x,

iv) according to DIN ENISO 11664-4: 2012-5 to 10 a, and

v) according to DIN ENISO 11664-4:2012 from 0 to 30 b,

And

i) a maximum roughness amplitude Sz of 20-800 μm,

ii) an arithmetic average roughness Sa of 2 to 80 μm, and

iii) a root mean square roughness Sq of 2-20 μm.

23. The decorative wood substrate according to any one of claims 16 to 22, wherein the decorative wood substrate is a fiberboard product, preferably a High Density Fiber (HDF) board, a Medium Density Fiber (MDF) board, a Low Density Fiber (LDF) board, a particle board, an Oriented Strand Board (OSB), a hardboard or a thermal insulation board.

24. The decorative wood substrate according to any one of claims 16 to 23, wherein the decorative wood substrate has a flexural strength of ≥ 5N/mm2, preferably 10-50N/mm2 and most preferably 15-45N/mm 2; and/or an elastic modulus of 500N/mm2 or more, preferably 1000-; and/or an internal bond strength of 0.10N/mm2 or more, more preferably 0.2-1.4N/mm2 and most preferably 0.4-1.2N/mm 2; and/or a thickness swell after 24 hours water storage of 20% or less, more preferably 2.0-15.0% and most preferably 4.0-10%; and/or a brightness of at least 50%, more preferably at least 65%, even more preferably at least 75% and most preferably at least 80%.

25. The decorative wood substrate according to claims 16 to 24, wherein at least one coated side of the decorative wood substrate has a surface density of 900-.

26. the decorative wood substrate according to any one of claims 16 to 25, wherein the decorative wood substrate further comprises

d) At least one protective layer and/or at least one decorative finish on the at least one decorative finish

e) In case the at least one decorative finish is present on only one side, the at least one backing layer, preferably in the form of paper, on the side of the decorative wood substrate opposite the at least one decorative finish.

27. The decorative wood substrate according to claim 26, wherein the at least one protective layer comprises a transparent non-thermoplastic resin, preferably selected from urea-formaldehyde resins, melamine resins, epoxy resins and mixtures thereof.

28. use of at least one dry or liquid coating composition as defined in any one of claims 1 or 4 to 7 for improving the mechanical properties and especially the bending strength, the elastic modulus, the internal bond strength and/or the thickness swell of a decorative wood substrate.

29. use of the decorative wood-based board as defined in claims 16 to 27 in: floor applications, furniture, walls, preferably wall panels, roof panels, display cases, storage units, speakers, preferably speaker boxes, and shop accessories.

Technical Field

The present invention relates to a method of manufacturing a decorative wood substrate, the use of at least one dry or liquid coating composition comprising at least one inorganic particulate filler material and at least one binder for coating a decorative wood substrate on-line, and the use of at least one dry or liquid coating composition comprising at least one inorganic particulate filler material and at least one binder for improving the mechanical properties of a decorative wood substrate. Furthermore, the invention relates to the use of the decorative wood-based panel in flooring applications, furniture, walls, roof panels, display cases, storage units, loudspeakers and shop accessories.

Background

decorative wood-based panels are widely used for indoor applications, such as in furniture, doors, floors, houses, wall linings, sound enclosures, stair treads or panel substrates, due to their reasonable cost, wide and flexible range of applications, consistency of strength, stability of dimensions, good processability and variability of their decorative finish. Such wood-based boards are composite products, which mainly comprise wood particles or wood fibers bonded together with or without a binder under heat and pressure. Subsequent decorative treatment of such raw wood substrates by painting, applying decorative paper or foil or direct printing provides the wood substrate with an attractive custom design.

Such panels and methods of making them are described in a number of documents. For example, US 2011/0171412 a1 relates to a directly printed lightweight panel, in particular a floor panel, comprising a lightweight MDF or LDF carrier board having a density of 750kg/m3 or less; a decorative layer printed on the carrier plate; and a transparent protective coating. The different layers and coatings are applied in such a way that the surface structure and/or the optical properties of the carrier sheet are at least partially visible and are thus incorporated into the design of the decorative layer. US 2013/0240137 a1 relates to a method for applying a decor to the upper surface of a composite wood board, in particular an MDF or HDF board, wherein the method is characterized in that at least one second decor produced by digital printing is applied to a first decor produced by gravure printing. EP 2589488 a1 discloses a carrier-attached copper foil used in the manufacture of a laminate, and aims to achieve an improvement in handling capacity during the production of a printed board and a cost reduction based on the improved yield. EP 2196508 a1 relates to a bulk layer for painting unpolished or polished surfaces of wood-based material boards, comprising a silane primer (8-12g/m2) and 20% by weight of a filler additive of nanoparticle size to the primer, wherein the silane is obtained by hydrolysis and condensation and is used in the form of an aqueous solution. DE 102008017438 a1 relates to a coated wood floor panel, characterized in that the coating is a coating with a vibration absorption in the range of 8s-22s as measured according to EN ISO 1522. WO 2008/061765 a1 discloses a method of coating a board of wood-based material, in particular a wood board, plywood or parquet, with a flowable plastic material. The method comprises applying the plastic material as a single thick layer onto a sheet of wood-based material and creating an embossed structure by means of a web of material or a structured roller. After the embossed structure is created, the plastic material is cured to create a wear-resistant surface. US 2008/0032120 a1 relates to a panel made of a wood material with a surface coating having a base coat applied to the wood material and at least one lacquer coating and functional component. Panels made of wood material with a low cost surface coating that can be easily applied and is optically attractive are produced. Finally, EP 2105320 a1 relates to a method for processing wood-based panels (in particular MDF or HDF panels) which involves sealing with melamine resin and printing a pattern directly onto the sealing layer and hot pressing before adding a protective layer of melamine resin. A method of processing wood or wood products, in particular MDF or HDF boards, involves (a) coating the top of the board with a sealing layer of melamine resin, (b) printing a pattern on the sealing layer, (c) coating the pattern with a protective layer of melamine resin, and (d) pressing the board at elevated temperature until the layers melt and bond together with the printed pattern between them. WO 2006/042651 a1 relates to light-coloured to white wood material panels produced from bleached wood fibres and/or vat-dyed with white pigment. DE 4310191 a1 relates to wood based panels comprising inorganic porous materials and flame retardants. The inorganic porous material includes a porous material made of an inorganic material. For example, these may be materials having an inorganic oxide such as silicon oxide or aluminum oxide as a main component, which has a granular structure filled with minute closed pores. US 5,422,170A and US 5,705001A relate to wood-based panels for which wood fibers, inorganic porous materials, flame retardants and organic binders for bonding these materials are mixed together and hot press molded to obtain the wood-based panel. US 2004/0258898 a1 relates to a method of manufacturing a fire retardant composite panel, the method comprising: producing a water-based slurry of partially soluble boron salts; adding a binder to the wood material; and separately introducing the water-based slurry into the wood-based material for flame retardancy thereof. US 2009/169812 a1 relates to a method of manufacturing a composite product from waste material, the method comprising the steps of: a) obtaining a fibrous material produced by heat treating waste material with pressurized steam; b) mixing the fibrous material with a binding material; c) forming the mixture into a shape; d) pressing the shaped mixture under pressure; and e) hardening the mixture; wherein the method further comprises the steps of separating the fibrous material and deodorizing the fibrous material. US 5,705,001 a relates to a method of manufacturing a wood based panel, the method comprising the steps of: mixing wood fibers, an inorganic porous material and a flame retardant, wherein the mixture ratio is at least 50 parts by weight of the inorganic porous material and 15-60 parts by weight of the flame retardant per 100 parts by weight of the wood fibers; applying a binder to the mixture; and then hot press molding the mixture to form a wood-based panel in which the wood fiber is a main component, and performing the step so that the wood-based panel has a density of 0.27g.cm-3 or less. Unpublished european patent application EP 15196997.9 relates to a particle board comprising a) a wood particle-based layer having a first side and an opposite side, the wood particle-based layer comprising i) wood particles in an amount of 60.0 to 97.5 parts by weight (d/d) and at least one particulate calcium carbonate-containing material in an amount of 2.5 to 40.0 parts by weight (d/d), based on the total dry weight of the wood particles and the at least one particulate calcium carbonate-containing material of the wood particle-based layer; and b) at least one surface layer of wood particles in contact with the first side and/or the opposite side of the wood particle-based layer, the at least one surface layer of wood particles comprising i) wood particles in an amount of 70.0 to 97.5 parts by weight (d/d) and at least one particulate calcium carbonate-containing material in an amount of 2.5 to 30.0 parts by weight (d/d), based on the total dry weight of the wood particles and the at least one particulate calcium carbonate-containing material of the at least one surface layer of wood particles, wherein the sum of the amounts of the wood particles and the at least one particulate calcium carbonate-containing material in each of the wood particle and the at least one surface layer of wood particles is 100.0 parts by weight (d/d), based on the total dry weight of the wood particles and the at least one particulate calcium carbonate-containing material in the layer. Unpublished european patent application EP 16150612.6 relates to a method for manufacturing a wood based board, a wood based board and the use of a liquid coating composition comprising at least one particulate filler material and at least one binder for coating a wood based board in-line. EP 2944621 a1 relates to a fiberboard product comprising a) fibers in an amount of from 50.0 to 99.0 parts by weight (d/d) based on the total dry weight of the fibers and at least one particulate calcium carbonate-containing material, wherein i) fibers in an amount of from 0 to 20.0% by weight based on the total amount of dry fibers have a size classified at a mesh screen width of 0.05mm, ii) fibers in an amount of from 50.0 to 90.0% by weight based on the total amount of dry fibers have a size classified at a mesh screen width of 1.0mm, and iii) fibers in an amount of from 70.0 to 100.0% by weight based on the total amount of dry fibers have a size classified at a mesh screen width of 3.0mm, b) at least one particulate calcium carbonate-containing material in an amount of from 1.0 to 50.0 parts by weight (d/d), based on the total dry weight of the fibers and the at least one particulate calcium carbonate-containing material, the at least one particulate calcium carbonate-comprising material has a weight median particle size d50 of 0.5-150.0 μm, and additionally, c) at least one binder in an amount of 0.05-25.0 parts by weight (d/d) based on the total dry weight of the fibers and the at least one particulate calcium carbonate-comprising material, and d) at least one wax in an amount of 0-5.0 parts by weight (d/d) based on the total dry weight of the fibers and the at least one particulate calcium carbonate-comprising material, wherein the sum of the amounts of the fibers and the at least one particulate calcium carbonate-comprising material is 100.0 parts by weight (d/d) based on the total dry weight of the fibers and the at least one particulate calcium carbonate-comprising material. EP 2226201 a1 relates to a method which involves spreading a layer of resin-glued wood fibres by a spreading device to form a fibre cake and compressing the fibre cake under pressure and temperature. The fiber cake is conveyed by a conveyor in the machine direction to a pressing device where the fiber cake is pressed to form a wood fiber board of a desired thickness. A printing device is arranged above the conveying device and between the dispersing device and the pressing device. A pattern is applied to the fibrous cake prior to hot pressing.

Although a wide variety of decorative wood-based panels with customized properties including strength, elasticity properties, optical properties and further processability are already available on the market, a general disadvantage of said decorative wood-based panels is that their manufacture requires energy consuming, cost consuming and time consuming processing steps for the preparation of the wood-based panel surface prior to the decorative treatment. In particular, the raw wood-based boards produced are typically surface treated after hot pressing by sanding, leveling, applying primers, adhesives and/or paper layers to improve the surface characteristics and/or mechanical properties of the board for subsequent decorative treatment. Such a decorative treatment may be, for example, painting, lamination with printed and/or impregnated decorative paper, foil or veneer, or direct printing on the board by inkjet printing, rotogravure printing, or the like. Furthermore, it is common in the art to apply a backing layer or balancing layer (e.g. in the form of a backing paper) on the side of the board opposite the decoration to improve the mechanical properties of the board. Such additional processing steps are often required to impart a uniform surface to the reverse side of the panel to allow proper bonding to the substrate or to avoid warping of the panel under tension on the first side caused by the decorative finish (e.g., decor paper). Another disadvantage is that the manufacturing process of decorative panels for flooring applications typically requires a relatively expensive high density fiberboard as the raw substrate to provide increased surface robustness and Brinell hardness (Brinell hardness).

However, the above-cited prior art is not particularly focused on providing an efficient manufacturing method for a decorative wood-based board, and in particular, the following such a method of providing a decorative wood-based board is not mentioned: the method avoids or at least reduces the need for energy-consuming, cost-consuming and time-consuming (post-) processing steps for surface preparation such as sanding, leveling, applying primers or adhesives and/or balancing layers.

Disclosure of Invention

Therefore, there is a continuing need in the art for a manufacturing method of a decorative wood base plate for avoiding the implementation of a (post) treatment step for surface preparation of the raw wood base plate prior to the decorative treatment. There is also a need for a method of providing a decorative wood substrate having improved surface characteristics (e.g., optical or physical properties) compared to existing decorative wood substrates. Furthermore, a novel method for manufacturing a decorative wood-based board is of particular interest, which provides maintained or even improved mechanical properties (e.g. bending strength and elastic modulus, internal bond strength, thickness swelling, elastic properties) for the decorative wood-based board.

Furthermore, there is a continuing need in the art for decorative wood substrates having improved surface characteristics such as optical characteristics (especially brightness or image quality) or increased surface density. There is furthermore a need for decorative wood substrates in which important mechanical properties such as flexural strength and modulus of elasticity, internal bond strength, thickness swelling, elastic properties and further processability are maintained or even improved.

It is therefore an object of the present invention to provide an improved method for manufacturing a decorative wood-based board. A further object is to provide a method for manufacturing a decorative wood based board which avoids or reduces the need for a treatment step of surface preparation of the wood based board prior to decorative treatment, in particular direct printing or application of decorative paper. Another object is to provide a method for manufacturing a decorative wood-based panel which can be carried out under energy-efficient, cost-effective and time-efficient conditions, i.e. by avoiding (post-) processing steps. It is a further object to provide a method for manufacturing a decorative wood substrate having improved surface properties, in particular optical properties such as surface brightness or quality of the printed image, or physical properties such as increased surface density. A further object is to provide a method for manufacturing a decorative wood substrate which allows to provide a decorative wood substrate wherein important mechanical properties groups such as bending strength and modulus of elasticity, internal bond strength, thickness swelling, elastic properties and further processability are maintained or even improved, preferably which relate to the international DIN standard. Further objects can be gathered from the following description of the invention.

One or more of the above objects are solved by the present invention. According to a first aspect, the invention relates to a method as defined in independent claim 1.

Advantageous embodiments of the inventive method for manufacturing a decorative wood-based board are defined in the respective dependent claims. When referring to embodiments of the present invention in the following, it is to be understood that these embodiments relate to the method of the present invention, the wood-based board of the present invention and the use of the present invention, and that these embodiments are also disclosed in combination.

According to one aspect of the present application, a method for manufacturing a decorative wood-based board is provided.

The method comprises the following steps:

a) Providing wood particles and/or fibres in dry form or in the form of an aqueous suspension,

b) Providing at least one dry or liquid coating composition comprising at least one inorganic particulate filler material and at least one binder,

c) Forming a wood based mat having a first side and an opposite side from the wood particles and/or fibres provided in step a),

d) Prepressing the wood-based mat of step c) into a prepressed wood-based mat,

e) Applying at least one layer of the at least one dry or liquid coating composition of step b) onto a first and/or opposite side of the pre-pressed wood based mat obtained in step d),

f) Hot-pressing the pre-pressed wood-based mat obtained in step e) into a solid wood-based board,

g) Applying at least one decorative finish (finishing) onto the first and/or the opposite side of the wood substrate obtained in step f) by inkjet printing, by rotogravure printing, by applying decorative paper, decorative foil or a liquid coating.

The inventors have surprisingly found that decorative wood based boards with excellent surface properties can be prepared by the above method without carrying out further processing steps. Thus, no or less common surface preparation steps (such as sanding or applying a primer) are required after hot pressing of the raw wood substrate to prepare the surface for subsequent decorative finishes. The possibility of directly subjecting the hot pressboard surface to a decorative treatment allows for a more efficient, economical and waste-economical production process for decorative wood-based boards. The inventors have also found that the application of a layer of the coating composition according to step e) of the present invention provides a wood substrate with improved mechanical properties. This has advantages such as the following: the coating may be used as a replacement for a balancing layer, such as a backing paper commonly used in the art of making decorative wood substrates. The inventors have also surprisingly found that by the process of the invention it is possible to produce decorative wood substrates with a high surface density on the coated side, even if the board is based on low or medium density wood substrates such as particle board, oriented strand board or medium density fiberboard. This allows the decorative wood-based panels of the present invention to replace relatively expensive high density fiberboard, for example, in flooring applications. Furthermore, by the method according to the invention, a decorative wood substrate is provided, wherein the decorative wood substrate has improved surface properties, and in particular improved optical properties.

According to one embodiment of the invention, the wood particles and/or fibers of step a) are derived from a primary wood source such as softwood species, hardwood species, non-wood fiber plants, or secondary wood sources, preferably recycled wood, and mixtures thereof.

According to another embodiment of the invention, the wood particles and/or fibers of step a) are combined simultaneously or separately in any order with at least one base binder and/or at least one additive, preferably the at least one base binder is selected from the group consisting of phenol-formaldehyde resin (PF), urea-formaldehyde resin (UF), melamine-formaldehyde resin (MF), melamine-urea-formaldehyde resin (MUF), urea-melamine-formaldehyde resin (UMF), urea-melamine-phenol resin (UMPF), epoxy resin, methylene diphenyl diisocyanate resin (MDI), polyurethane resin (PU), resorcinol resin, starch or carboxymethyl cellulose and mixtures thereof, and/or the at least one additive is selected from the group consisting of waxes, colorants, fillers, dispersants, biocides, water-soluble organic solvents, organic solvents, Hardeners, flame retardants and mixtures thereof.

According to yet another embodiment of the invention, the wood particles of step a) are wood chips.

According to one embodiment of the present invention, the at least one inorganic particulate filler material of step b) is selected from dolomite, Ground Calcium Carbonate (GCC), preferably Ground Calcium Carbonate (GCC) selected from marble, chalk, limestone and mixtures thereof, Precipitated Calcium Carbonate (PCC), preferably Precipitated Calcium Carbonate (PCC) selected from one or more of the aragonite, vaterite and calcite mineralogical crystal forms, Modified Calcium Carbonate (MCC), magnesium hydroxide, talc, gypsum, titanium dioxide, kaolin, silicates, mica, barium sulfate, calcined clay, uncalcined (hydrous) clay, bentonite, inorganic pigments and mixtures thereof.

According to another embodiment of the present invention, the at least one inorganic particulate filler material of step b) is provided i) in powder form, or ii) in the form of an aqueous slurry comprising the filler material in an amount of 1.0 to 80.0% by weight, preferably 30.0 to 78.0% by weight, more preferably 40.0 to 78.0% by weight and most preferably 45.0 to 78.0% by weight, based on the total weight of the aqueous slurry.

According to yet another embodiment of the present invention, the at least one inorganic particulate filler material of step b) is at least one inorganic particulate calcium carbonate-comprising material having a median particle size d50 of from 0.1 μm to 150.0 μm, more preferably from 0.2 μm to 100.0 μm and most preferably from 0.3 μm to 50.0 μm and/or having a specific surface area as measured by BET nitrogen method of from 0.5 to 200.0m2/g, more preferably from 0.5 to 100.0m2/g and most preferably from 0.5 to 75.0m 2/g.

According to one embodiment of the invention, the at least one binder of step b) is selected from the group consisting of alkyd resins, epoxy ester resins, poly (vinyl alcohol), poly (vinyl pyrrolidone), poly (vinyl acetate), poly (oxazoline), poly (vinylacetamide), partially hydrolyzed poly (vinyl acetate/vinyl alcohol), poly ((meth) acrylic acid), poly ((meth) acrylamide), poly (alkylene oxide), polyethers, saturated polyesters, sulfonated or phosphated polyesters and polystyrenes, poly (styrene-co- (meth) acrylates), poly (styrene-co-butadiene), polyurethane latexes, poly (n-butyl (meth) acrylate), poly (2-ethylhexyl (meth) acrylate), (meth) acrylates such as copolymers of n-butyl (meth) acrylate and ethyl (meth) acrylate, poly (ethylene glycol mono (meth) acrylate, poly (ethylene glycol mono (meth) acrylate), poly (ethylene glycol mono (meth) acrylate, poly (meth), Copolymers of vinyl acetate and n-butyl (meth) acrylate, casein, copolymers of polyvinyl chloride, gelatin, cellulose ethers, zeatin, albumin, chitin, chitosan, dextran, pectin, collagen derivatives, collodion (collodian), agar-agar, arrowroot, guar gum, carrageenan, starch, tragacanth gum, xanthan gum or rhamsan (rhamsan), and mixtures thereof.

According to another embodiment of the present invention, the at least one dry or liquid coating composition of step b) comprises the at least one inorganic particulate filler material in an amount of 60 to 98% by weight, preferably 70 to 98% by weight and most preferably 80 to 98% by weight, and the at least one binder in an amount of 2 to 40% by weight, preferably 2 to 30% by weight and most preferably 2 to 20% by weight, based on the total dry weight of the at least one coating composition.

According to yet another embodiment of the present invention, the at least one dry or liquid coating composition of step b) further comprises at least one compound selected from matting agents, coalescents or film-forming agents, defoamers, dispersants, rheology agents, crosslinking agents, biocides, light stabilizers, preservatives, hardeners, flame retardants, wax or fat containing release agents, and mixtures thereof, preferably the at least one dry or liquid coating composition of step b) comprises the at least one compound in an amount of 2.0 to 8.0% by weight, such as 3.0 to 7.0% by weight, based on the total dry weight of the at least one coating composition.

according to one embodiment of the invention, a single-or multi-layer wood based mat is formed in step c).

According to another embodiment of the invention, the pre-pressing step d) is carried out at ambient temperature, such as 10-60 ℃, more preferably 15-30 ℃ and/or at a pressure in the range of 5-40 bar, preferably 8-35 bar.

according to yet another embodiment of the invention, the coating step e) is carried out by metered size press, curtain coating, spray coating or roll coating.

According to one embodiment of the invention, the coating step e) is performed on the first and opposite sides of the pre-pressed wood based mat to produce a decorative wood based board coated on the first and opposite sides, and/or the coating step e) is performed a second time using a different or the same liquid coating composition of step b).

according to another embodiment of the invention, the hot pressing step f) is carried out at a temperature in the range of 130 ℃ and 260 ℃, more preferably 160 ℃ and 240 ℃.

According to yet another embodiment of the invention, the decorative wood substrate is a fiberboard product, preferably a High Density Fiber (HDF) board, a Medium Density Fiber (MDF) board, a Low Density Fiber (LDF) board, a particle board, an Oriented Strand Board (OSB), a hardboard or a thermal insulation board.

According to yet another embodiment of the invention, in step g), the at least one decorative finish is applied in the form of a liquid coating as a paint layer.

According to another embodiment of the invention, the method comprises the further step h) of applying at least one protective layer on the at least one decorative finish obtained in step g), and/or

i) in case the at least one decorative finish is present on only one side, at least one backing layer, preferably in the form of paper, is applied on the side of the decorative wood substrate opposite the at least one decorative finish.

According to another embodiment of the invention, the at least one protective layer comprises a transparent non-thermoplastic resin, preferably selected from urea-formaldehyde resins, melamine resins, epoxy resins and mixtures thereof.

According to another aspect of the present invention, a decorative wood-based board is provided. The decorative wood substrate comprises

a) A substrate of wood particles and/or fibres as defined in any one of claims 1 to 3,

b) At least one coating on the first and/or reverse side of the solid wood substrate, wherein the coating comprises

i) At least one inorganic particulate filler material as defined in one of claims 1, 4, 5 or 7, having a ratio [ d80/d20] of the particle size d80 to the particle size d20 of from 0.5 to 1.0, and

ii) at least one binder as defined in one of claims 1, 6 or 7,

c) at least one decorative finish on the first and/or reverse side of the wood-based board.

According to one embodiment of the decorative wood-based panel according to the invention, the at least one coating layer at least partially penetrates into the surface of the wood-based panel.

According to another embodiment of the decorative wood-based panel according to the invention, the at least one decorative finish is present on the coating on the first and/or opposite side of the wood-based panel.

According to another embodiment of the decorative wood-based board according to the invention, the at least one decorative finish is present on one side of the wood-based board and the at least one coating layer is present on the opposite side of the wood-based board and represents or is part of the backing layer.

According to another embodiment of the decorative wood-based board according to the invention the at least one inorganic particulate filler material has i) a particle size d98 of <500 μm, ii) a particle size d80 of 0.1-250 μm, iii) a median particle size d50 of 0.1-150 μm, and iv) a particle size d20 of 0.1-50 μm.

According to another embodiment of the decorative wood substrate according to the present invention, the surface of the coated side of the wood substrate has i) a brightness of 50-100% according to ISO R457(Tappi452) and DIN 6167, ii) a yellowness of 2-70% according to ISO R457(Tappi452) and DIN 6167, iii) a gloss of 2-100% according to DIN EN ISO 11664-4: 2012L, iv) from 50 to 100 according to DIN EN ISO 11664-4: 2012-5 to 10 a, v) according to DIN EN ISO 11664-4:2012 b from 0 to 30.

According to one embodiment of the decorative wood substrate according to the present invention, at least one coated surface of the decorative wood substrate has i) a maximum roughness amplitude Sz of 20 to 800 μm, ii) an arithmetic average roughness Sa of 2 to 80 μm, and iii) a root mean square roughness Sq of 2 to 20 μm.

According to another embodiment of the decorative wood substrate according to the invention the at least one inorganic particulate filler material has i) <500 μm particle size d98, ii) a particle size d80 of 0.1-250 μm, iii) a median particle size d50 of 0.1-150 μm, and iv) a particle size d20 of 0.1-50 μm, and the surface of the coated side of the decorative wood substrate has i) a brightness of 50-100% according to ISO R457(Tappi452) and DIN 6167, ii) a yellowness of 2-70% according to ISO R457(Tappi452) and DIN 6167, iii) a yellowness of 2-70% according to DIN EN ISO 11664-4: 2012L, iv) from 50 to 100 according to DIN EN ISO 11664-4:2012 a from-5 to 10, and v) according to DIN EN ISO 11664-4:2012 b from 0 to 30 and i) a maximum roughness amplitude Sz of 20-800 μm, ii) an arithmetic average roughness Sa of 2-80 μm and iii) a root mean square roughness Sq of 2-20 μm.

According to one embodiment of the decorative wood substrate according to the invention, the decorative wood substrate is a fiberboard product, preferably a High Density Fiber (HDF) board, a Medium Density Fiber (MDF) board, a Low Density Fiber (LDF) board, a particle board, an Oriented Strand Board (OSB), a hardboard or a thermal insulation board.

According to another embodiment of the decorative wood-based panel according to the invention, the decorative wood-based panel has a bending strength of ≥ 5N/mm2, preferably 10-50N/mm2 and most preferably 15-45N/mm 2; and/or an elastic modulus of 500N/mm2 or more, preferably 1000-; and/or an internal bond strength of 0.10N/mm2 or more, more preferably 0.2-1.4N/mm2 and most preferably 0.4-1.2N/mm 2; and/or a thickness swell after 24 hours water storage of 20% or less, more preferably 2.0-15.0% and most preferably 4.0-10%; and/or a brightness of at least 50%, more preferably at least 65%, even more preferably at least 75% and most preferably at least 80%.

according to another embodiment of the wood substrate according to the invention at least one coated side of the decorative wood substrate has a surface density of 900-.

According to another embodiment of the decorative wood-based board of the present invention, the decorative wood-based board further comprises

d) At least one protective layer and/or at least one decorative finish on the at least one decorative finish

e) In case the at least one decorative finish is present on only one side, the at least one backing layer, preferably in the form of paper, on the side of the decorative wood substrate opposite the at least one decorative finish.

According to another embodiment of the decorative wood-based panel according to the invention, the at least one protective layer comprises a transparent non-thermoplastic resin, preferably selected from urea-formaldehyde resins, melamine resins, epoxy resins and mixtures thereof.

According to another aspect of the present invention there is provided the use of at least one dry or liquid coating composition as defined herein for the in-line coating of decorative wood substrates.

According to another aspect of the present invention there is provided the use of at least one dry or liquid coating composition as defined herein for improving the mechanical properties and especially the bending strength, the elastic modulus, the internal bond strength and/or the thickness swell of a decorative wood substrate.

According to yet another aspect of the present invention there is provided the use of a decorative wood-based panel as defined herein in flooring applications, furniture, walls (preferably wall panels), roof panels, display cases, storage units, loudspeakers (preferably loudspeaker enclosures) and shop accessories.

It is to be understood that for the purposes of this invention, the following terms have the following meanings:

A "suspension" or "slurry" in the meaning of the present invention comprises insoluble solids and a solvent or liquid (preferably water), and optionally other additives such as dispersants, biocides and/or thickeners, and generally contains a large amount of solids and thus is more viscous and can have a higher density than the liquid from which it is formed.

The term "aqueous" suspension or slurry refers to a system in which the liquid phase comprises, preferably consists of, water. However, the term does not exclude that the liquid phase of the aqueous slurry or suspension comprises a minor amount of at least one water miscible organic solvent selected from the group consisting of methanol, ethanol, acetone, acetonitrile, tetrahydrofuran, and mixtures thereof. If the aqueous suspension or slurry comprises at least one water-miscible organic solvent, the liquid phase of the aqueous slurry comprises the at least one water-miscible organic solvent in an amount of from 0.1 to 40.0% by weight, preferably from 0.1 to 30.0% by weight, more preferably from 0.1 to 20.0% by weight and most preferably from 0.1 to 10.0% by weight, based on the total weight of the liquid phase of the aqueous suspension or slurry. For example, the liquid phase of the aqueous suspension or slurry is comprised of water. If the liquid phase of the aqueous suspension or slurry is comprised of water, the water to be used may be any useful water, such as tap and/or deionized water.

For the purposes of this application, a "water-insoluble" material is defined as a material that: when 100g of the material is mixed with 100g of deionized water and filtered at 20 ℃ on a 0.2 μm pore size filter to recover a liquid filtrate, it provides less than or equal to 0.1g of recovered solid material after evaporation of 100g of the liquid filtrate at 95-100 ℃ at ambient pressure. "Water-soluble" materials are defined as materials that: when 100g of the material is mixed with 100g of deionized water and filtered at 20 ℃ on a 0.2 μm pore size filter to recover a liquid filtrate, it provides greater than 0.1g of recovered solid material after evaporation of 100g of the liquid filtrate at 95-100 ℃ at ambient pressure.

The term "d/d" in the meaning of the present invention refers to the dry amount of the additive based on the dry amount of the defined material.

The term "inorganic" particulate filler material in the meaning of the present invention refers to a material which does not contain carbon-carbon bonds and which is not derived from biomass.

The term inorganic "particulate" filler material refers to separate and distinct solid particles of inorganic filler material.

The term "filler material" refers to natural or synthetic substances added to materials such as paper, plastics, rubber, paints and adhesives, etc., to reduce the consumption of more expensive materials such as binders or to enhance the technical properties of the product. Typical fillers used in the corresponding field are well known to those skilled in the art.

the term "binder" as used in the present invention is a compound or mixture of compounds conventionally used to bind particles of one material together or to bind particles of one material and particles of two or more other materials together to form a composite material.

for the purposes of the present invention, the particle size "dx" represents the following diameters: with respect to this diameter, x% by weight of the particles have a diameter smaller than dx. This means that the d20 value is the particle size where 20% of all particles are smaller than the particle size and the d80 value is the particle size where 80% of all particles are smaller than the particle size. The d50 value is therefore the median particle size, i.e. 50% of all particles are smaller than this particle size. For example, the d50 (weight) value is the weight median particle size, i.e., 50% by weight of all particles are smaller than this particle size, and the d50 (volume) value is the volume median particle size, i.e., 50% by volume of all particles are smaller than this particle size. For the purposes of the present invention, the "particle size" of the particles having a median particle size d50>45 μm is determined by the volume-determined particle size distribution. Furthermore, the "particle size" of the particles having a median particle size d50 ≦ 45 μm is determined by the weight-determined particle size distribution. It can thus be understood that if the particles comprise particles having a median particle size d50 of ≦ 45 μm and >45 μm, then the particle sizes given throughout this application are based on a combination of weight and volume determined particle sizes. To determine the weight median particle size d50 value, a Sedigraph (e.g., Sedigraph TM 5120 or Sedigraph TM 5100) from Micromeritics Instrument Corporation, i.e., a sedimentation method, may be used. The volume median particle size d50 value of the at least one inorganic particulate filler material was measured by laser diffraction. In this method, the particle size is determined by measuring the intensity of scattered light as the laser beam passes through the dispersed particulate sample. The measurements were performed using a Mastersizer 2000 or Mastersizer 3000 from Malvern Instruments ltd. (operating instrument software version 1.04). If the particles are spherical and have a constant density throughout the particle size distribution, the weight-determined particle size distribution corresponds to the volume-determined particle size distribution.

when the term "comprising" is used in this description and claims, it does not exclude other elements of major or minor functional importance not indicated. For the purposes of the present invention, the term "consisting of … … (of) is to be considered as a preferred embodiment of the term" comprising or including ". If in the following it is defined that a group set (group) comprises at least a certain number of embodiments, this is also to be understood as disclosing a group set, which preferably consists of only these embodiments.

Wherever the terms "comprising" or "having" are used, these terms are considered equivalent to "comprising" as defined above.

Where an indefinite or definite article is used when referring to a singular noun e.g. "a", "an" or "the", this includes a plural of that noun unless something else is specifically stated.

terms such as "available" or "definable" and "obtained" or "defined" are used interchangeably. This for example means that unless the context clearly dictates otherwise, the term "obtained" is not meant to indicate that for example an embodiment must be obtained by, for example, a sequence of steps following the term "obtained", although the term "obtained" or "defined" always includes such a restrictive understanding as a preferred embodiment.

As mentioned above, the inventive method for manufacturing a decorative wood based board comprises at least the method steps of a), b), c), d), e), f) and g). Further details of the invention, and in particular the aforementioned steps of the method of the invention for manufacturing a decorative wood-based board, will be referred to in the following.

Characterization of step a): providing wood particles and/or fibres

According to step a) of the process of the present invention, wood particles and/or fibres are provided in dry form or in the form of an aqueous suspension.

Thus, one requirement is to provide wood particles and/or fibers.

It is understood that the wood particles may comprise one or more wood particles.

thus, the wood particles may comprise one wood particle. Alternatively, the wood particles may comprise a mixture of two or more wood particles. For example, the wood particles comprise a mixture of two or three wood particles. Preferably, the wood particles comprise one wood particle.

It is understood that the wood particles present according to the invention are not limited to specific wood particles, as long as they are suitable for the preparation of wood substrates.

Preferably, the wood particles are wood-based particles. The term "wood-based" particles in the meaning of the present invention refers to the general definition, i.e. wood is a fibrous hard substance that constitutes the majority of the trunks and branches of softwood and hardwood species.

Such wood based particles may be any wood based particles well known to the person skilled in the art and generally used for wood based boards.

For example, the wood particles are derived from virgin wood sources such as softwood species, hardwood species, non-wood fiber plants, and mixtures thereof. Additionally or alternatively, the wood particles are derived from a secondary wood source, such as recycled wood.

The wood particles may have a specific size. For example, the wood particles have

i) Particle lengths in the range of 0.4 to 15mm, more preferably 3 to 15mm and most preferably 5 to 15mm, and/or

ii) a particle thickness in the range of 0.1-2.0mm, more preferably 0.2-1.5mm and most preferably 0.25-1.0mm, and/or

iii) a ratio of particle length to particle thickness of from 2 to 60mm, more preferably from 5 to 60mm and most preferably from 10 to 60 mm.

it is understood that particle "length" refers to the longest dimension of the wood particle. The term "thickness" of the particles refers to the shortest dimension of the wood particles. It is understood that length or thickness refers to an average length or average thickness.

Preferably, the wood particles have

i) Particle lengths in the range of 0.4 to 15mm, more preferably 3 to 15mm and most preferably 5 to 15mm, or

ii) a particle thickness in the range of 0.1-2.0mm, more preferably 0.2-1.5mm and most preferably 0.25-1.0mm, or

iii) a ratio of particle length to particle thickness of from 2 to 60mm, more preferably from 5 to 60mm and most preferably from 10 to 60 mm.

Alternatively, the wood particles have

i) Particle lengths in the range of 0.4 to 15mm, more preferably 3 to 15mm and most preferably 5 to 15mm, and

ii) a particle thickness in the range of from 0.1 to 2.0mm, more preferably from 0.2 to 1.5mm and most preferably from 0.25 to 1.0mm, and

iii) a ratio of particle length to particle thickness of from 2 to 60mm, more preferably from 5 to 60mm and most preferably from 10 to 60 mm.

in one embodiment, the wood particles have a median particle size d50 in the range of from 0.4 to 15mm, more preferably from 3 to 15mm, and most preferably from 5 to 15 mm.

Additionally or alternatively, the wood particles have a particle size d90 in the range of 2-60mm, more preferably 5-60mm and most preferably 10-60 mm.

Specific examples of wood particles include poplar, spruce, pine, alder, birch, beech, oak, and mixtures thereof.

Additionally or alternatively, wood fibers are provided. Preferably, the wood fibers may comprise one or more wood fibers.

Thus, the wood fibers may comprise one wood fiber. Alternatively still, the wood fibers may comprise a mixture of two or more wood fibers. For example, the wood fibers may comprise a mixture of two or three wood fibers. Preferably, the wood fibers comprise one wood fiber.

Furthermore, the wood fibres may be in the form of separate wood fibres or wood fibre bundles.

It is understood that the wood fibers according to the present invention are not limited to specific wood fibers as long as they are suitable for the preparation of a wood substrate.

The term "wood" fibers in the meaning of the present invention refers to the general definition, i.e. wood is a fibrous hard substance that constitutes the majority of the trunks and branches of softwood and hardwood species.

For example, the wood fibers are preferably derived from virgin wood sources such as softwood species, hardwood species, non-wood fiber plants, and mixtures thereof. Additionally or alternatively, the wood fibers are derived from a secondary wood source, such as recycled wood.

It is understood that the wood fibers have a specific size. Preferably, the wood fibers

i) An amount of 0-20% by weight, based on the total amount of dried wood fibres, has a size graded at a mesh screen width of 0.05mm,

ii) an amount of 50 to 90% by weight, based on the total amount of dried wood fibres, has a size graded at a mesh screen width of 1.0mm, and

iii) an amount of 70 to 100% by weight, based on the total amount of dried wood fibres, has a size graded at a mesh screen width of 3.0 mm.

The size of the wood fibers can be measured using any device suitable for particle separation, particle classification, and particle size analysis. For example, the measurement may be performed by sieve analysis using an air-jet sieving device. The air jet sieving device measures the size of particles by applying an air stream to the particles placed in a sieve through a rotating slit nozzle located under the sieve. The granules are thus separated from each other and classified by air dispersion and simultaneously sucked through the sieve over a certain period of time. The balance between the amount of particles before placement in the screen and after classification is considered to be through classification in grams. Depending on the number of mesh widths selected, the grading is repeated starting from the smallest mesh width to the largest mesh width. Thus, for each mesh width, the percentage of the total amount of particles classified can be calculated. A suitable device is Alpine e e200LS from ALPINE AG, HOSOKAWA, Germany.

Specific examples of wood fibers include pine, fir, spruce, hemlock, poplar, eucalyptus, cypress, poplar, cedar, beech, oak, birch, maple, bamboo, cereal fibers, algae fibers, seed fibers, fruit fibers, and mixtures thereof.

It is understood that the wood particles may also be in the form of wood chips. Preferably, the wood particles in the form of wood chips may comprise one or more wood chips.

Thus, wood particles in the form of wood chips may comprise one type of wood chip. Alternatively, the wood particles in the form of wood chips may comprise a mixture of two or more wood chips. For example, wood particles in the form of wood chips may comprise a mixture of two or three wood chips. Preferably, the wood particles in the form of wood chips comprise one wood chip.

It is understood that the wood chips according to the present invention are not limited to specific wood chips as long as they are suitable for the preparation of wood-based boards.

If the wood particles are in the form of wood chips, the wood chips may have a specific size. Preferably, the wood chips have a particle length in the range of 1-100mm, more preferably 2-75mm and most preferably 3-50 mm.

it is understood that the particle "length" refers to the longest dimension of the wood chips.

Specific examples of wood chips include pine, fir, spruce, hemlock, poplar, eucalyptus, cypress, poplar, cedar, beech, oak, birch, maple, bamboo, cereal fiber, algae fiber, seed fiber, fruit fiber, and mixtures thereof.

In one embodiment, wood particles or wood fibers are provided.

Alternatively, a mixture of wood particles and wood fibers is provided. In this case, the ratio of wood particles to wood fibres may vary within wide ranges. For example, the mixture comprises wood particles and wood fibers in the range of 100:1 to 1:100, preferably 50:1 to 1:50 and most preferably 20:1 to 1:20 [ particles: fiber ].

Wood particles and/or fibres are provided in dry form or in the form of an aqueous suspension.

The term "dry form" with respect to the wood particles and/or fibers provided in step a) refers to wood particles and/or fibers having a moisture content of about 10.0% by weight or less than 10.0% by weight, for example 4-8% by weight, based on the total weight of the wood particles and/or fibers. It will be appreciated that a higher moisture content is not preferred, as it may be critical during the pre-pressing step d) and especially during the hot-pressing step f).

Thus, in case the moisture content is > 10.0% by weight based on the total weight of the wood particles and/or fibers, the wood particles and/or fibers may optionally be pre-dried to reduce their moisture content. The optional pre-drying of the wood particles and/or fibres to a desired level is preferably carried out in a pre-dryer, such as a tube dryer. Tubular dryers, such as single or multi-stage tubular dryers, are well known in the art and are widely used for drying wood particles and/or fibers in the manufacture of wood-based boards. The wood particles and/or fibers may be dried for a period of time and/or at a temperature sufficient to reduce the moisture content of the wood particles and/or fibers to a desired level. The drying time and/or temperature may be adjusted depending on the temperature and moisture content of the wood particles and/or fibers.

It will thus be appreciated that in the process of the present invention for manufacturing decorative wood-based boards, the wood particles and/or fibres are preferably provided in dry form.

Further optionally, the wood particles and/or fibers are provided in the form of an aqueous suspension.

The aqueous suspension of wood particles and/or fibres may be formed by suspending wood particles and/or fibres provided in dry form (i.e. as obtained after a pre-dryer) in water or by diluting wood particles and/or fibres obtained after a refiner to the desired wood particle and/or fibre and/or chip content.

if the wood particles and/or fibres are provided in the form of an aqueous suspension, the aqueous suspension preferably comprises wood particles and/or fibres in an amount of 1.0-80.0% by weight, based on the total weight of the aqueous suspension. More preferably, the aqueous suspension comprises wood particles and/or fibres in an amount of 5.0-75.0 wt. -%, more preferably 10.0-70.0 wt. -%, and most preferably 15.0-60.0 wt. -%, based on the total weight of the aqueous suspension.

In one embodiment, the wood particles and/or fibers of step a) are combined simultaneously or separately in any order with at least one base binder and/or at least one additive. Thus, the at least one base binder and/or the at least one additive may be added to the wood particles and/or the fibers, respectively, simultaneously or in any order, in a manner known to the skilled person.

For example, the wood particles and/or fibers of step a) are combined separately in any order with at least one base binder and/or at least one additive. Further optionally, the wood particles and/or fibers of step a) are simultaneously combined with at least one base binder and/or at least one additive. If the wood particles and/or fibers of step a) are simultaneously combined with at least one base binder and/or at least one additive, the at least one base binder and/or at least one additive are preferably provided in the form of a mixture, i.e. the at least one base binder and/or at least one additive may be pre-mixed before adding the wood particles and/or fibers.

The term "at least one" base binder in the meaning of the present invention means that the base binder comprises, preferably consists of, one or more base binders.

In one embodiment of the invention, the at least one base binder comprises, preferably consists of, one base binder. Further optionally, the at least one base binder comprises, preferably consists of, two or more base binders. For example, the at least one base binder comprises, preferably consists of, two or three base binders. Preferably, the at least one base binder comprises, preferably consists of, one base binder.

For example, the at least one base binder may be present in an amount of 0.01 to 25.0 parts by weight (d/d), based on the total dry weight of the wood particles and/or fibers of step a).

The at least one base binder may be one or more binders, which are base materials well known to those skilled in the art and generally used for wood substrates. For example, the at least one base binder is selected from the group consisting of phenol-formaldehyde resin (PF), urea-formaldehyde resin (UF), melamine-formaldehyde resin (MF), melamine-urea-formaldehyde resin (MUF), urea-melamine-formaldehyde resin (UMF), urea-melamine-phenol resin (UMPF), epoxy resin, methylene diphenyl diisocyanate resin (MDI), polyurethane resin (PU), resorcinol resin, starch or carboxymethylcellulose and mixtures thereof. Preferably, the at least one base binder is selected from the group consisting of phenol-formaldehyde resin (PF), urea-formaldehyde resin (UF), melamine-formaldehyde resin (MF), melamine-urea-formaldehyde resin (MUF), urea-melamine-formaldehyde resin (UMF), urea-melamine-phenol resin (UMPF), epoxy resin, methylene diphenyl diisocyanate resin (MDI), polyurethane resin (PU) and mixtures thereof. Most preferably, the at least one base binder is a urea-formaldehyde resin (UF).

additionally or alternatively, the at least one additive may be present in an amount of 0.01 to 10.0 parts by weight (d/d), based on the total dry weight of the wood particles and/or fibers of step a). The amount of the at least one additive optionally included may be determined according to standard methods and the desired properties of the final decorative wood substrate.

The term "at least one" additive in the meaning of the present invention means that the additive comprises, preferably consists of, one or more additives.

In one embodiment of the invention, the at least one additive comprises, preferably consists of, one additive. Further optionally, the at least one additive comprises, preferably consists of, two or more additives. For example, the at least one additive comprises, preferably consists of, two or three additives. Preferably, the at least one additive comprises, preferably consists of, two or more additives.

The at least one additive may be one or more additives that are well known to those skilled in the art and are typically used for wood substrates. For example, the at least one additive is selected from the group consisting of waxes, colorants, fillers, dispersants, biocides, hardeners, flame retardants, and mixtures thereof. Preferably, the at least one additive is selected from the group consisting of waxes, hardeners, and mixtures thereof. More preferably, the at least one additive comprises, most preferably consists of, a wax and a hardener.

The combining (or mixing) of the wood particles and/or fibers of step a) with the at least one base binder and/or the at least one additive may be accomplished by any conventional means known to those skilled in the art. The person skilled in the art will adapt the combining (or mixing) conditions, such as mixing speed and temperature, according to his process equipment. Additionally, the combining (or mixing) may be performed under homogenization and/or particle separation conditions.

characterization of step b): providing at least one inorganic particulate filler material and at least one binder

According to step b) of the present invention, at least one dry or liquid coating composition is provided, which comprises at least one inorganic particulate filler material and at least one binder.

It is therefore a requirement of the present invention to provide at least one dry or liquid coating composition comprising at least one inorganic particulate filler material and at least one binder.

In the meaning of the present invention, the term "at least one" inorganic particulate filler material means that the inorganic particulate filler material comprises, preferably consists of, one or more inorganic particulate filler materials.

In one embodiment, the at least one inorganic particulate filler material comprises, preferably consists of, one inorganic particulate filler material. Further optionally, the at least one inorganic particulate filler material comprises, preferably consists of, two or more inorganic particulate filler materials. For example, the at least one inorganic particulate filler material comprises, preferably consists of, two or three inorganic particulate filler materials. Preferably, the at least one inorganic particulate filler material comprises, preferably consists of, an inorganic particulate filler material.

For example, the at least one inorganic particulate filler material is selected from the group consisting of dolomite, Ground Calcium Carbonate (GCC), Precipitated Calcium Carbonate (PCC), Modified Calcium Carbonate (MCC), magnesium hydroxide, talc, gypsum, titanium dioxide, kaolin, silicates, mica, barium sulfate, calcined clay, uncalcined (hydrous) clay, bentonite, inorganic pigments, and mixtures thereof.

"dolomite" in the meaning of the present invention is a calcium-magnesium carbonate mineral having the chemical composition CaMg (CO3)2 ("CaCO 3. MgCO 3"). The dolomite mineral comprises at least 30.0% by weight of MgCO3, preferably greater than 35.0% by weight, greater than 40.0% by weight, typically 45.0 to 46.0% by weight of MgCO3 based on the total weight of dolomite.

"ground calcium carbonate" (GCC) means in the meaning of the present invention calcium carbonate obtained from natural sources (for example limestone, marble or chalk) and which is processed by wet and/or dry treatments such as grinding, screening and/or classification (for example by means of a cyclone or classifier).

According to one embodiment of the invention, the GCC is obtained by dry milling. According to another embodiment of the invention, the GCC is obtained by wet grinding and subsequent drying.

In general, the grinding step can be carried out with any conventional grinding device, for example under conditions such that the refinement results mainly from the impact with the auxiliary body, i.e. in one or more of the following: ball mills, rod mills, vibratory mills, crushers, centrifugal impact mills, vertical bead mills, attritors, pin mills, hammer mills, pulverizers, shredders, delumpers, cutters (knife cutters), or other such equipment known to those skilled in the art. Where the calcium carbonate-comprising material comprises a wet-milled calcium carbonate-comprising material, this milling step may be carried out under conditions such that autogenous milling occurs and/or by horizontal ball milling and/or other such methods known to those skilled in the art. The wet processed calcium carbonate-containing material thus obtained can be washed and dewatered by well known methods, e.g. by flocculation, filtration or forced evaporation (before drying). The subsequent drying step may be performed in a single step, such as spray drying, or in at least two steps. It is also common for such calcium carbonate materials to undergo a beneficiation step (such as a flotation, bleaching or magnetic separation step) to remove impurities.

In one embodiment of the invention, the GCC is selected from marble, chalk, limestone and mixtures thereof.

"precipitated calcium carbonate" (PCC) is in the meaning of the present invention a synthetic material, usually obtained by precipitation after reaction of carbon dioxide with lime in an aqueous environment or by precipitation of calcium and carbonate ion sources in water. The PCC may be one or more of aragonite, vaterite, and calcite mineralogical crystal forms. Preferably, the PCC is one of aragonite, vaterite, and calcite mineralogical crystalline forms.

Aragonite is usually in the form of needles, whereas vaterite belongs to the hexagonal system. Calcite can form scalenohedral, prismatic, spheroidal and rhombohedral forms. PCC can be produced in different ways, for example by precipitation with carbon dioxide, the soda lime process or the Solvay process, wherein PCC is a by-product of ammonia production. The PCC slurry obtained may be mechanically dewatered and dried.

Within the meaning of the present invention, a "modified calcium carbonate" (MCC) may be characterized as a natural ground or precipitated calcium carbonate having internal structural modifications or surface reaction products, i.e., "surface-reacted calcium carbonate". "surface-reacted calcium carbonate" is a material comprising calcium carbonate and a water-insoluble (preferably at least partially crystalline) acid anionic calcium salt on the surface. Preferably, the insoluble calcium salt extends from the surface of at least a portion of the calcium carbonate. The calcium ions of said at least partially crystalline calcium salt forming said anion are mostly derived from the starting calcium carbonate material. MCCs are described, for example, in US 2012/0031576 a1, WO 2009/074492 a1, EP 2264109 a1, WO 00/39222 a1 or EP 2264108 a 1.

Preferably, the at least one inorganic particulate filler material comprises at least one Ground Calcium Carbonate (GCC) or at least one Modified Calcium Carbonate (MCC). Preferably, the at least one Ground Calcium Carbonate (GCC) is selected from marble, chalk, limestone and mixtures thereof, and more preferably from marble or chalk.

Preferably, the at least one inorganic particulate filler material is at least one inorganic particulate calcium carbonate-containing material. The at least one inorganic particulate calcium carbonate-comprising material may further comprise, in addition to calcium carbonate, a metal oxide, such as titanium dioxide and/or aluminum trioxide, a metal hydroxide, such as aluminum trihydroxide, a metal salt, such as a sulphate, a silicate, such as talc and/or kaolin and/or mica, a carbonate, such as magnesium carbonate and/or gypsum, satin and mixtures thereof.

According to one embodiment of the present invention, the amount of calcium carbonate in the at least one inorganic particulate calcium carbonate-comprising material is ≥ 10.0% by weight, preferably ≥ 20.0% by weight, based on the total dry weight of the at least one inorganic particulate calcium carbonate-comprising material. Preferably, the amount of calcium carbonate in the at least one inorganic particulate calcium carbonate-comprising material is ≥ 50.0% by weight, even more preferably ≥ 90.0% by weight, more preferably ≥ 95.0% by weight and most preferably ≥ 97.0% by weight, based on the total dry weight of the at least one inorganic particulate calcium carbonate-comprising material.

Preferably, the at least one inorganic particulate filler material of step b) has a specific size. For example, the at least one inorganic particulate filler material has a median particle size d50 of 0.1 to 150.0 μm. In one embodiment of the invention, the at least one inorganic particulate filler material has a median particle size d50 of from 0.2 μm to 100.0 μm, more preferably from 0.3 μm to 50.0 μm and most preferably from 0.5 μm to 3.0 μm.

The at least one inorganic particulate filler material may have a top cut of, for example, less than 150.0 μm. As used herein, the term "top cut" (or top size) refers to a particle size value in which at least 98.0% of the material particles are smaller than that size. Preferably, the at least one inorganic particulate filler material has a top cut of less than 140.0 μm and more preferably less than 120.0 μm.

In one embodiment, the at least one inorganic particulate filler material has

i) < particle size d98 of 500 μm,

ii) a particle size d80 of 0.1 to 250 μm,

iii) a median particle size d50 of from 0.1 to 150 μm, and

iv) a particle size d20 of 0.1 to 50 μm.

additionally or alternatively, the at least one inorganic particulate filler material has a ratio of particle size d80 to particle size d20[ d80/d20] of from 0.5 to 1.0.

Preferably, the at least one inorganic particulate filler material has

i) < particle size d98 of 500 μm,

ii) a particle size d80 of 0.1 to 250 μm,

iii) a median particle size d50 of from 0.1 to 150 μm,

iv) a particle size d20 of 0.1 to 50 μm, and

v) a ratio of particle size d80 to particle size d20[ d80/d20] of 0.5 to 1.0.

In one embodiment, the at least one inorganic particulate filler material has a specific surface area, as measured by the BET nitrogen method, of from 0.5 to 200.0m2/g, more preferably from 0.5 to 100.0m2/g and most preferably from 0.5 to 75.0m 2/g.

the term "specific surface area" (in m2/g) of the at least one inorganic particulate calcium carbonate-comprising material within the meaning of the present invention is determined using the BET method well known to the person skilled in the art (ISO 9277: 2010).

The term "at least one" binder in the meaning of the present invention means that the binder comprises, preferably consists of, one or more binders.

in one embodiment of the invention, the at least one binder comprises, preferably consists of, a binder. Further optionally, the at least one binder comprises, preferably consists of, two or more binders. For example, the at least one binder comprises, preferably consists of, two or three binders. Preferably, the at least one binder comprises, preferably consists of, two binders.

It is understood that the binder of step b) may be the same or different from the optional base binder of step a). For example, the binder of step b) is the same as the optional base binder of step a). Further optionally, the binder of step b) is different from the optional base binder of step a).

Preferably, the binder of step b) is different from the optional base binder of step a).

The at least one binder may be one or more binders that are well known to those skilled in the art and are typically used for the coating of wood substrates. In one embodiment, the at least one binder of step b) is selected from the group consisting of alkyd resins, epoxy ester resins, poly (vinyl alcohol), poly (vinyl pyrrolidone), poly (vinyl acetate), poly (oxazoline), poly (vinyl acetamide), partially hydrolyzed poly (vinyl acetate/vinyl alcohol), poly ((meth) acrylic acid), poly ((meth) acrylamide), poly (alkylene oxide), polyethers, saturated polyesters, sulfonated or phosphated polyesters and polystyrene, poly (styrene-co- (meth) acrylates), poly (styrene-co-butadiene), polyurethane latexes, poly (n-butyl (meth) acrylate), poly (2-ethylhexyl (meth) acrylate), (meth) acrylates such as copolymers of n-butyl (meth) acrylate and ethyl (meth) acrylate, poly (ethylene glycol mono (meth) acrylate), poly (ethylene glycol mono (meth) acrylate, poly (meth), Copolymers of vinyl acetate and n-butyl (meth) acrylate, casein, copolymers of polyvinyl chloride, gelatin, cellulose ethers, zeatin, albumin, chitin, chitosan, dextran, pectin, collagen derivatives, collodion, agar-agar, arrowroot, guar gum, carrageenan, starch, tragacanth, xanthan or rhamsan, and mixtures thereof. Preferably, the at least one binder of step b) is selected from the group consisting of alkyd resins, epoxy ester resins, poly (vinyl alcohol), poly (vinylpyrrolidone), poly (vinyl acetate), poly (oxazoline), poly (vinylacetamide), partially hydrolyzed poly (vinyl acetate/vinyl alcohol), poly ((meth) acrylic acid), poly ((meth) acrylamide), poly (alkylene oxide), polyethers, saturated polyesters, sulfonated or phosphated polyesters and polystyrenes, poly (styrene-co- (meth) acrylates), poly (styrene-co-butadiene), polyurethane latexes, poly (n-butyl (meth) acrylate), poly (2-ethylhexyl (meth) acrylate), (meth) acrylates such as copolymers of n-butyl (meth) acrylate and ethyl (meth) acrylate, poly (ethylene glycol methyl) acrylate), poly (ethylene glycol methyl methacrylate), poly (ethylene glycol methyl, Copolymers of vinyl acetate and n-butyl (meth) acrylate, casein, copolymers of polyvinyl chloride, starch, and mixtures thereof. More preferably, the at least one binder of step b) is selected from the group consisting of poly (vinyl alcohol), poly (vinyl pyrrolidone), poly (vinyl acetate), poly (oxazoline), poly (vinyl acetamide), partially hydrolyzed poly (vinyl acetate/vinyl alcohol), starch, and mixtures thereof. Most preferably, the at least one binder of step b) is a mixture of poly (vinyl alcohol) and starch.

The term "at least one" dry or liquid coating composition in the meaning of the present invention means that the dry or liquid coating composition comprises, preferably consists of, one or more dry or liquid coating compositions.

In this regard, it is contemplated that different separate coating compositions may be used. For example, the process may be carried out using two different coating compositions applied simultaneously or sequentially. Thus, it is understood that the expression "one or more coating compositions" means that different, separate coating compositions are provided and used. It will be appreciated, however, that this does not exclude the possibility of using, for example, two different coating compositions which are combined into one coating composition comprising at least two inorganic particulate filler materials and two binders before they are provided in step b).

In one embodiment of the present invention, the at least one dry or liquid coating composition comprises, preferably consists of, a dry or liquid coating composition. Further optionally, the at least one dry or liquid coating composition comprises, preferably consists of, two or more dry or liquid coating compositions. For example, the at least one dry or liquid coating composition is preferably composed of two or three dry or liquid coating compositions. The at least one dry or liquid coating composition preferably comprises, preferably consists of, a dry or liquid coating composition.

It will be appreciated that the at least one inorganic particulate filler material preferably comprises the at least one inorganic particulate filler material and at least one binder in specific amounts.

For example, the at least one dry or liquid coating composition of step b) comprises the at least one inorganic particulate filler material in an amount of 60-98% by weight, preferably 70-98% by weight and most preferably 80-98% by weight, based on the total dry weight of the at least one coating composition, and the at least one binder in an amount of 2-40% by weight, preferably 2-30% by weight and most preferably 2-20% by weight, based on the total dry weight of the at least one coating composition.

Thus, the at least one dry or liquid coating composition of step b) comprises the at least one inorganic particulate filler material in an amount of 60-98% by weight and the at least one binder in an amount of 2-40% by weight. More preferably, the at least one dry or liquid coating composition preferably comprises the at least one inorganic particulate filler material in an amount of 70-98% by weight and the at least one binder in an amount of 2-30% by weight. Most preferably, the at least one dry or liquid coating composition comprises the at least one inorganic particulate filler material in an amount of 80-98% by weight and the at least one binder in an amount of 2-20% by weight. Said amounts are based on the total dry weight of the at least one coating composition and refer to the dry weight of the at least one inorganic filler material and to the dry weight of the at least one binder.

The term "dry" with respect to the at least one inorganic particulate filler material and the at least one binder should be understood as a material having less than 0.3% by weight of water relative to the weight of the at least one inorganic particulate filler material and the at least one binder. The% water content is determined according to the Coulometric Karl Fischer measurement method, wherein the at least one inorganic particulate filler material and the at least one binder are heated to 220 ℃ and the water content released as steam and separated using a nitrogen stream (100ml/min) is determined in a Coulometric Karl Fischer unit.

The at least one inorganic particulate filler material and the at least one binder are provided in step b) in the form of at least one dry or liquid coating composition.

For the purposes of the present invention, the term "coating composition" refers to a composition that is applied to the surface of a pre-pressed wood mat and remains primarily on the surface of the hot-pressed wood substrate.

The term "dry" with respect to the coating composition is understood to be a composition having less than 0.3% by weight of water relative to the weight of the coating composition. The% water content was determined according to the Coulometric Karl Fischer measurement method, wherein the coating composition was heated to 220 ℃ and the water content released as steam and separated using a nitrogen stream (100ml/min) was determined in a Coulometric Karl Fischer unit.

the term "liquid" in relation to the coating composition is understood to mean a composition which is liquid at Standard Ambient Temperature and Pressure (SATP) which means a temperature of 298.15K (25 ℃) and an absolute pressure of exactly 100000 Pa (1 bar, 14.5psi, 0.98692 atm). The liquid is preferably a suspension (or dispersion).

if at least one dry coating composition is provided in step b), it is understood that the at least one inorganic particulate filler material and the at least one binder are preferably combined in dry form for obtaining the at least one dry coating composition.

If at least one liquid coating composition is provided in step b), the at least one inorganic particulate filler material and/or the at least one binder are in the form of an aqueous suspension. Preferably, the at least one inorganic particulate filler material and the at least one binder are in the form of an aqueous suspension. More preferably, the at least one inorganic particulate filler material is in the form of an aqueous suspension. To form the at least one liquid coating composition of step b), the at least one binder is preferably mixed (e.g. in dry form) into the at least one inorganic particulate filler material provided in the form of an aqueous suspension.

In view of this, the at least one inorganic particulate filler material may be provided in powder form, i.e. in dry form. The term "dry" with respect to the at least one inorganic particulate filler material is understood to be a material having less than 0.3% by weight of water relative to the weight of the at least one inorganic particulate filler material.

If the at least one inorganic particulate filler material is provided in the form of an aqueous suspension, the aqueous suspension preferably comprises the at least one inorganic particulate filler material in an amount of 1.0 to 80.0% by weight, based on the total weight of the aqueous suspension. More preferably, the aqueous suspension comprises the at least one inorganic particulate filler material in an amount of 30.0-78.0% by weight, more preferably 40.0-78.0% by weight and most preferably 45.0-78.0% by weight, based on the total weight of the aqueous suspension.

The at least one dry or liquid coating composition may further comprise at least one compound which is well known to the person skilled in the art and is generally used for the coating of wood substrates.

the term "at least one" compound in the meaning of the present invention means that the compound comprises, preferably consists of, one or more compounds.

In one embodiment of the invention, the at least one compound comprises, preferably consists of, one compound. Further optionally, the at least one compound comprises, preferably consists of, two or more compounds. For example, the at least one compound comprises, preferably consists of, two or three compounds. Preferably, the at least one compound comprises, preferably consists of and is thus a mixture of compounds. For example, the at least one dry or liquid coating composition of step b) further comprises at least one compound selected from matting agents, coalescents or film-forming agents, defoamers, dispersants, rheology agents, crosslinking agents, biocides, light stabilizers, preservatives, hardeners, flame retardants, wax or fat containing release agents and mixtures thereof.

If the at least one coating composition comprises at least one compound, the at least one liquid coating composition of step b) is preferably formed in such a way that the at least one inorganic particulate filler material, preferably in dry form, is mixed into an aqueous suspension or solution of the at least one compound, which is selected from matting agents, coalescents or film-forming agents, defoamers, dispersants, rheological agents, crosslinking agents, biocides, light stabilizers, preservatives, hardeners, flame retardants, wax or fat containing release agents and mixtures thereof. The at least one binder is then dispersed (preferably in dry form) into the suspension of the at least one inorganic particulate filler material and the at least one compound.

Thus, in one embodiment, the at least one dry or liquid coating composition comprises, preferably consists of, at least one inorganic particulate filler material, at least one binder and at least one compound selected from matting agents, coalescents or film-forming agents, defoamers, dispersants, rheology agents, crosslinking agents, biocides, light stabilizers, preservatives, hardeners, flame retardants, wax or fat containing release agents and mixtures thereof, and optionally water.

Alternatively still, the at least one dry or liquid coating composition consists of the at least one inorganic particulate filler material and the at least one binder and optionally water.

If the at least one dry or liquid coating composition further comprises at least one compound selected from matting agents, coalescents or film-forming agents, defoamers, dispersants, rheology agents, crosslinking agents, biocides, light stabilizers, preservatives, hardeners, flame retardants, wax or fat containing release agents and mixtures thereof, the at least one dry or liquid coating composition preferably comprises the at least one compound in an amount of 2.0 to 8.0% by weight, for example 3.0 to 7.0% by weight, based on the total dry weight of the at least one coating composition.

Characterization of step c): forming a wood based mat

According to step c) of the present invention, a wood based mat having a first side and an opposite side is formed from the wood particles and/or fibres provided in step a).

It is understood that the term "wood based mat formed of wood particles and/or fibers" refers to a mixture of the wood particles and/or fibers and the optional at least one base binder and/or at least one additive, which is used to form the base of the final decorative wood based board.

A mixture of wood particles and/or fibers and optionally at least one base binder and/or at least one additive is laid down into a uniform and consistent mat. This can be achieved in batch mode or by continuous formation, preferably by continuous formation.

The forming step c) can be carried out by all techniques and methods well known to the person skilled in the art for forming mats from wood particles and/or fibres and optionally at least one base binder and/or at least one additive. The forming step c) may be carried out, for example, with any conventional forming machine or other such equipment known to those skilled in the art, under conditions such that a continuous wood based mat is obtained. For example, wood particles and/or fibers and optionally at least one base binder and/or at least one additive are spread by hand or by back and forth movement of a pallet or hopper feeder or by air separation to form a wood based mat.

If the decorative wood-based board is manufactured in a wet process, the wood-based mat is preferably subjected to a step of reducing the water content of the mat. This drying can be carried out before or during or after process step c), preferably during process step c). Such drying may be performed by all techniques and methods well known to those skilled in the art for reducing the water content of wood based mats. This drying may be carried out by any conventional method (e.g. by mechanically applying pressure, hot air, vacuum, gravity or suction) or other such equipment known to the skilled person, so that a wood based mat is obtained having a reduced water content compared to the water content before drying. Preferably, the drying is carried out by mechanically applying pressure (e.g. a dewatering drum) followed by a hot air treatment.

it is understood that in step c) a single-or multi-layer wood based mat may be formed, preferably in step c).

In one embodiment, the multi-layer wood based mat is formed in multiple forming steps. For example, a three-layer wood based mat is formed in three forming steps.

The wood based mat obtained in the forming step c) has a first side and an opposite side.

characterization of step d): prepressing the wood-based cushion

Pre-pressing the wood based mat of step c) into a pre-pressed wood based mat according to step d) of the present invention.

thus, the wood based mat obtained in step c) is pre-pressed before applying the at least one dry or liquid coating composition of step b) and hot pressing.

the pre-pressing may be performed by all techniques and methods well known to the person skilled in the art for pre-pressing wood based mats into pre-pressed wood based mats. The pre-pressing may be done with any conventional pressing machine (e.g. single opening press, multiple opening batch press or continuous press) or other such equipment known to the person skilled in the art under conditions such that a pre-pressed wood base mat is obtained.

It is understood that the pre-pressing temperature, optional pressure and time will vary depending on the decorative wood substrate to be produced. The pre-pressing is preferably carried out at ambient temperature. Therefore, the pre-pressing is preferably carried out at a temperature of 10 to 60 ℃, more preferably 15 to 30 ℃, most preferably 15 to 25 ℃. Additionally or alternatively, the pre-pressing is performed at a pressure of 5-40 bar and preferably 8-35 bar.

The pre-pressing is therefore preferably carried out at ambient temperature or at a pressure of 5-40 bar and preferably 8-35 bar. Alternatively, the pre-pressing is carried out at ambient temperature and a pressure of 5-40 bar, preferably 8-35 bar.

preferably, the pre-pressing is performed at a temperature of 10-60 ℃, more preferably 15-30 ℃ and most preferably 15-25 ℃ and a pressure of 5-40 bar and preferably 8-35 bar.

Characterization of step e): applying at least one layer of the at least one dry or liquid coating composition onto the pre-pressed wood mat

According to step e) of the present invention, at least one layer of the at least one dry or liquid coating composition of step b) is applied onto the first and/or reverse side of the pre-pressed wood based mat obtained in step d).

Decisive for the process according to the invention are: the step of applying at least one layer of the at least one dry or liquid coating composition of step b) onto the first and/or the opposite side of the wood based mat is performed after the pre-pressing step but before the hot-pressing step. The inventors have surprisingly found that this sequence of steps results in a wood based board having excellent surface properties without the need to carry out further processing steps to prepare the surface of the board. In particular, a wood-based board is obtained, wherein the wood-based board has improved surface properties, and in particular improved optical properties and increased surface density. Further, a wood-based board having improved mechanical properties can be obtained.

In the meaning of the present invention, the term "at least one layer" of the at least one dry or liquid coating composition means that step e) comprises applying one or more layers of the at least one dry or liquid coating composition to the first and/or opposite side of the pre-pressed wood based mat obtained in step d).

in one embodiment of the invention, step e) comprises applying a layer of the at least one dry or liquid coating composition. Further optionally, step e) comprises applying two or more layers of the at least one dry or liquid coating composition. For example, step e) of the present invention may comprise applying two or three layers of the at least one dry or liquid coating composition. Preferably, step e) comprises applying a layer of the at least one dry or liquid coating composition.

It will be appreciated that where two or more dry or liquid coating compositions are provided in step b), each dry or liquid coating composition may be applied in the form of one or more layers as described above. According to one embodiment, the coating step e) is carried out one or more times using two or more different coating compositions.

The at least one layer of the at least one coating composition may be applied in dry or liquid form. According to one embodiment, the at least one layer of the at least one coating composition of the inventive method is applied in dry form in step e). According to another embodiment, the at least one layer of the at least one coating composition of the process of the present invention is applied in liquid form in step e). In this case, the method of the invention may further comprise a step e1) of drying the at least one coating. Preferably, the at least one layer of the at least one coating composition of the inventive process is applied in liquid form in step e).

one requirement is that: applying the at least one layer of the at least one dry or liquid coating composition of step b) at least on a first and/or opposite side of the pre-pressed wood based mat. Thus, according to one embodiment, the at least one layer of the at least one dry or liquid coating composition of step b) is applied onto the first side of the pre-pressed wood based mat. According to another embodiment, the at least one layer of the at least one dry or liquid coating composition of step b) is applied onto opposite sides of the pre-pressed wood based mat.

According to one embodiment, method step e) is performed on a first and an opposite side of the pre-pressed wood based mat to produce a wood based board coated on the first and the opposite side. This step may be performed separately for each side, or may be performed simultaneously on the first and opposite sides, preferably separately.

according to another embodiment, wherein the at least one layer of the at least one coating composition is in liquid form, method step e) and optionally step e1) are performed on both sides of the pre-pressed wood based mat to produce a wood based board coated on the first and opposite sides. These steps may be performed separately for each side, or may be performed simultaneously on the first and opposite sides.

The at least one coating layer may be applied to the pre-pressed wood-based mat by conventional coating means commonly used in the art. Suitable coating methods are, for example, metering size press, curtain coating, spray coating or roll coating, etc. Some of these methods allow for the simultaneous application of two or more layers, which is preferred from a manufacturing economy point of view. However, any other coating method suitable for forming a coating layer on the pre-pressed wood-based mat may be used.

in an exemplary embodiment, at least one layer of the at least one coating composition is applied by metered size press, curtain coating, or spray coating. In a preferred embodiment, the at least one coating is applied using spraying. In another preferred method, curtain coating is used to apply the at least one coating layer.

According to one exemplary embodiment, the at least one layer of the at least one liquid coating composition is applied by metering size press, curtain coating or spray coating (preferably curtain coating). According to another exemplary embodiment, the dry coating composition is applied by spreading or electrostatic powder coating.

It is understood that process step e) can be carried out as a batch or continuous process. If step e) is carried out in a continuous process, it is preferred to apply the at least one layer of the at least one dry or liquid coating composition of step b) only on the first side of the pre-pressed wood mat obtained in step d).

according to one embodiment of the present invention, the at least one liquid coating composition used to form the at least one coating layer has a solids content of 10 to 80% by weight, preferably 30 to 75% by weight, most preferably 40 to 70% by weight, based on the total weight of the at least one liquid coating composition.

The at least one liquid coating composition may have a Brookfield viscosity in the range of from 20 to 3000 mPas, preferably 100-3000 mPas, more preferably 150-2500 mPas and most preferably 200-1000 mPas.

The at least one layer of the at least one coating composition is preferably applied in a specific amount. According to one embodiment, the at least one layer of the at least one coating composition is applied in an amount of from 1 to 1000 g/m2, preferably from 10 to 500g/m2, more preferably from 50 to 300g/m2 and most preferably from 10 to 200g/m2, based on the dry weight of the at least one coating composition.

In order to facilitate the release of the surface of the wood based mat from the hot plate of the pressing machine after the hot pressing of step f), a release agent may advantageously further be applied to the first and/or the opposite side of the wood based board. Mold release agents used in the manufacture of wood-based boards typically contain waxes or fats and are commonly used in the art. Another option is to apply release paper, i.e. paper impregnated with release agent, to achieve an improved release of the hot pressed wood substrate from the press plate. The release paper can be removed after the hot pressing of step f). It is also understood that the release agent or the release paper may be applied to the coated and/or uncoated side of the pre-pressed wood based mat. The release agent and/or the release paper can be applied by conventional application means known to the person skilled in the art.

Thus, according to an embodiment of the present invention, step e) further comprises a step e1) of applying a release agent or release paper to at least one side of the pre-pressed wood based mat.

Characterization of step f): hot-pressing the pre-pressed wood-based cushion

Hot pressing the pre-pressed wood based mat obtained in step e) into a solid wood based panel according to step f) of the present invention.

The hot pressing of step f) may be performed by all techniques and methods well known to the skilled person for hot pressing pre-pressed wood based mats into solid wood based boards. The hot pressing of step f) may be carried out with any conventional pressing machine (e.g. single opening press, multi-opening batch press or continuous press) or other such equipment known to the skilled person under conditions such that a solid wood substrate is obtained. Preferably, the hot pressing step f) is carried out using a continuous press.

For example, heat and optionally pressure, preferably heat and pressure, is applied to the pre-pressed wood base mat in a hot pressing step, whereby wood particles and/or fibers are bonded together with the optional at least one base binder and/or at least one additive and the at least one coating layer comprising at least one inorganic particulate filler material and at least one binder and the optional at least one compound applied on the first and/or opposite side to form a solid wood base board in pressing step g).

It will be appreciated that the hot pressing temperature, optional pressure and time will vary depending on the solid wood-based panel to be produced. However, the hot pressing in step f) is preferably carried out at a temperature in the range of 130 ℃ to 260 ℃, more preferably 160 ℃ to 240 ℃.

In one embodiment, the hot pressing is performed at a pressing time factor of 10-25s/mm, preferably 10-20s/mm and most preferably 12-18s/mm in relation to the thickness of the plate.

After the hot pressing step f), the solid wood substrate may be cooled and/or stacked.

Depending on the further use of the hot pressed wood substrate, step f) may comprise further steps for surface preparation (e.g. sanding or any other means known in the art for surface preparation) to improve surface properties such as roughness, gloss, abrasiveness, etc. For example, if the wood-based board comprises only one coated side, which is used as or as part of the backing layer, it may be advantageous to prepare the surface of the uncoated side on the opposite side for the subsequent decorative treatment of step g) of the inventive method. The coated side of the wood substrate does not generally require further processing steps at this stage, regardless of its further use in the method of the invention. In other words, if the coated side represents a backing layer, this side typically does not require further processing steps such as sanding or leveling to prepare it for further use (e.g., bonding to a substrate). Furthermore, if the coated side of the board is the basis for the decorative treatment, surface preparation is generally not required to obtain good results for applying the decorative finish. However, if desired, the coated side of the surface may also be further prepared by processing steps commonly used in the art to further improve its surface properties.

Thus, according to one embodiment, step f) comprises step f 1): subjecting the first and/or the reverse side of the solid wood-based board obtained in step f) to further processing steps for surface preparation.

In case the at least one coating composition is applied only to the first or opposite side of the pre-pressed wood based mat, i.e. the solid wood based board of step f) comprises the at least one coating layer only on the first or opposite side, the uncoated side of the solid wood based board may be subjected to further treatment steps, such as sanding or applying a primer, for example to reduce the surface roughness and thereby improve the surface properties of the uncoated side of the solid wood based board for further treatment steps such as decorative finishing. Thus, according to one embodiment, step f) of the present invention further comprises step f 1): the uncoated side of the solid wood substrate, i.e. the side of the wood substrate not comprising the at least one coating layer, is subjected to further processing steps for surface preparation.

According to one embodiment, step f) of the present invention may further comprise step f 1): one side of the wood substrate comprising at least one coating layer is subjected to further treatment steps for surface preparation.

The solid wood substrate may be a fiberboard product, preferably a High Density Fiber (HDF) board, a Medium Density Fiber (MDF) board, a Low Density Fiber (LDF) board, a particle board, an Oriented Strand Board (OSB), a hardboard, or a thermal insulation board.

Characterization of step g): at least one decorative finish is applied to the first and/or opposite sides of the wood substrate.

according to step g) of the present invention, at least one decorative finish is applied by ink-jet printing, by rotogravure printing, by applying decorative paper, decorative foil or a liquid coating onto the first and/or reverse side of the wood substrate obtained in step f).

One requirement of the present invention is that: applying at least one decorative finish of step g) onto the first or opposite side of the wood substrate obtained in step f).

In the meaning of the present invention, the term "at least one" decorative finish means that step g) comprises applying one or more decorative finishes to the first and/or opposite side of the pre-pressed wood based mat obtained in step d). It will be apparent to those skilled in the art that this includes the possibility of applying one or more decorative modifications of the same kind, of the above-mentioned methods of inkjet printing, rotogravure printing, etc., or combinations thereof.

in one embodiment of the invention, step g) comprises applying a decorative finish. Further optionally, step g) comprises applying two or more decorative finishes. For example, step g) of the present invention may comprise applying two or three decorative finishes. Preferably step g) comprises applying a decorative finish.

According to one embodiment, the at least one decorative finish of step g) is applied onto the first side of the wood based board obtained in step f). According to another embodiment, the at least one decorative finish of step g) is applied to the opposite side of the wood substrate.

The decorative trim may also be applied on the first and opposite sides of the wood-based panel to produce a wood-based panel decorated on the first and opposite sides. According to one embodiment, step g) is performed on both sides (i.e. the first and the opposite side) of the wood-based board obtained in step f). This step may be performed separately for each side, or may be performed simultaneously on the first and opposite sides, preferably separately.

It is advantageous to perform the application of the decorative finish according to the method of the invention on the coated side of the wood substrate to improve the final appearance (e.g. brightness or print quality) of the decorative finish.

Thus, according to one embodiment, the at least one decorative finish of step g) is performed on the at least one coating layer of the first side of the wood based board obtained in step f). According to another embodiment, the at least one decorative finish of step g) is performed on the at least one coating layer on the opposite side of the wood based board obtained in step f). According to yet another embodiment, the at least one decorative finish of step g) is performed on the at least one coating layer on the first and opposite sides of the wood based board obtained in step f). Preferably, the at least one decorative finish of step g) is performed on the at least one coating layer of the first side of the wood based board obtained in step f).

In case the wood based panel obtained in step f) comprises only one coating layer on the first or opposite side, the application of the decorative finish according to the invention may also be performed on the side of the wood based panel not comprising a coating layer, i.e. on the side opposite to the coating layer on the first or opposite side. According to one embodiment, the decorative finish of step g) is performed on the opposite side of the first or reverse side comprising the at least one coating.

The at least one decorative finish of step g) may be applied in a batch or continuous mode. According to one embodiment, the at least one decorative finish of step g) is applied in a batch mode. According to one embodiment, the at least one decorative finish of step g) is applied in a continuous mode.

The at least one decorative finish according to the method of the present invention may be applied by ink jet printing, rotogravure printing or by applying a decorative paper, a decorative foil or a liquid coating.

According to one embodiment, the at least one decorative finish of step g) may be applied by ink jet printing. The application of the at least one decorative finish by inkjet printing in step g) may be carried out using any digital inkjet printing device known to the person skilled in the art for direct printing on wood substrates, such as the inkjet printer Jupiter JPT-L from Hymmen. The inkjet printer may comprise one or more inkjet print heads. It will be appreciated that the ink jet print head may apply ink to a fixed wood substrate by moving the print head over the wood substrate or moving the wood substrate relative to a fixed ink jet print head or a combination of both. Further, inkjet printing may be performed at a predetermined printing speed, typically measured in the length of the printed wood substrate per minute. The printing speed of the inkjet printing according to step g) may be in the range of 1-50m/min, preferably 5-40m/min, more preferably 10-35m/min and most preferably 15-30 m/min.

The inkjet printing apparatus may be used with water-based inks, organic solvent-based inks, UV curable inks or any other ink suitable for direct printing on wood substrates. The ink applied in step g) may be dried by any means suitable for drying the ink on the wood substrate, for example by applying a gas stream, a hot gas stream, infrared radiation or microwave radiation. In case a UV curable ink is applied, the inkjet printing of step g) may further comprise a step g1) of UV curing the ink. This step may be performed by any means known in the art for curing inks by UV radiation, such as by UV mercury vapor lamps or UV light emitting diodes or a combination of both.

According to one embodiment, the at least one decorative finish of step g) may be applied by rotogravure printing. Such printing may be performed by any rotogravure printing press used for direct printing on solid wood substrates known to those skilled in the art. The rotogravure printing press may comprise one or more printing cylinders. The rotogravure printing press may be used with water-based inks, organic solvent-based inks, UV curable inks, or any other ink suitable for direct printing on wood substrates. The ink applied in step g) may be dried by any means suitable for drying the ink on the wood substrate, for example by applying a gas stream, a hot gas stream, infrared radiation or microwave radiation. In case a UV curable ink is applied, the inkjet printing of step g) may further comprise a step g1) of UV curing the ink. This step may be performed by any means known in the art for curing inks by UV radiation, such as by UV mercury vapor lamps or UV light emitting diodes or a combination of both.

The inventors have surprisingly found that direct printing by e.g. ink jet printing on the side of a wood substrate comprising at least one coating layer leads to better printing results (e.g. in terms of print gloss or ink density) than direct printing on a wood substrate not comprising a coating layer according to the present invention.

According to another embodiment, the at least one decorative finish of step g) may be performed by applying decorative paper. The decorative paper of step g) may be any paper known in the art for decorative finishes for wood-based boards. The decorative paper may be printed and/or coated. In addition, the decorative paper may be impregnated with or contacted with a thermosetting or binder agent, such as melamine-formaldehyde resins, urea-formaldehyde resins, polyester resins, phenol resins, polyvinyl acetate or acrylic based binders, and/or combinations thereof. Additionally, the decorative paper may be contacted with any other agent known in the art of making decorated wood substrates, such as a resin hardener or wetting agent. Preferably, the decorative paper is a light basis weight paper (light basis weight paper) having a weight in the range of 20-120g/m2, more preferably 30-80g/m2 and most preferably 40-70g/m 2. The decorative paper of step g) may be applied to the wood substrate by any means known in the art of wood substrates. For example, the decorative paper of step g) may be applied under heat and pressure in a short-cycle press.

the inventors have surprisingly found that one side of the wood substrate comprising the at least one coating of step e) shows a high refractive index according to standard DIN EN ISO 2409: 2013, which results in a stronger robustness of the decorative paper to the wood substrate. It was furthermore found that the improved optical properties of the coated side of the wood substrate also have a favorable effect on the optical properties on the side of the wood substrate modified with decorative paper. In other words, if a coating layer is present under the decorative paper of the wood-based board, the overall brightness is improved as compared to a decorative wood-based board that does not include a coating layer under the paper.

According to another embodiment, the at least one decorative finish of step g) may be performed by applying a decorative foil. The decorative foil of step g) may be a thermoplastic foil. Suitable thermoplastic foils may be, for example, polypropylene foils or polyvinyl chloride foils. However, decorative paper foils such as high or low pressure laminates and/or melamine foils may also be used. Furthermore, the decorative foil may be impregnated with or contacted with a thermosetting or adhesive agent, such as melamine-formaldehyde resin, urea-formaldehyde resin, polyester resin, phenol resin, a polyvinyl acetate or acrylic based adhesive, and/or combinations thereof. The decorative foil of step g) may be applied to the wood substrate by any means known in the art of wood substrates, for example by a film vacuum press.

According to yet another embodiment of the invention, the at least one decorative finish of step g) may be performed by applying a liquid coating. The liquid coating may be a varnish, lacquer or any other liquid coating suitable for decorating wood substrates.

According to a preferred embodiment, the at least one decorative finish is applied in the form of a liquid coating as a lacquer layer. The lacquer (lacquer) of step g) may be chosen from clear or pigmented lacquers, preferably clear lacquers. It may be a water-based paint, such as a water-based acrylic latex paint, or alternatively, a solvent-based paint. Non-limiting examples of solvent-based paints are nitrocellulose paints, paints based on alkyd resins, epoxy resins, urea-formaldehyde resins or polyurethane paints, or paints based on acrylic polymers or other synthetic polymers. However, any other lacquer known to the person skilled in the art to be suitable as a liquid coating for decorative wood-based boards may also be used.

The liquid coating of step g) may be applied by spraying, curtain coating, flow coating, brushing, wiping, dipping or by any other means known to those skilled in the art for applying a lacquer to a surface. The liquid coating may be further subjected to step g2) of drying the liquid coating. This drying step may be carried out by any means known in the art, such as (hot) gas flow, infrared, microwave or ultraviolet radiation, etc.

Optionally characterization of steps h) and i):

the method according to the invention may further comprise optional method steps, such as applying a protective layer or backing layer to improve the mechanical properties, wear resistance and/or abrasiveness of the panel.

According to one embodiment, the process of the invention further comprises a step h) of applying at least one protective layer on the at least one decorative finish obtained in step g).

In the meaning of the present invention, the term "at least one" protective layer means that step h) may comprise applying one or more protective layers on the at least one decorative finish obtained in step g).

In one embodiment of the invention, step h) may comprise applying a protective layer. Further optionally, step h) may comprise applying two or more protective layers. For example, step h) of the present invention comprises applying two or three protective layers. Preferably, step h) comprises applying a protective layer.

The protective layer may comprise any transparent non-thermoplastic resin known in the art to protect the decorated or undecorated surface of the wood substrate from abrasion, chemicals, heat or any other external influences that degrade the surface properties of the wood substrate.

According to one embodiment, the at least one protective layer of step h) of the process of the invention comprises a transparent non-thermoplastic resin, preferably selected from urea-formaldehyde resins, melamine resins, epoxy resins and mixtures thereof.

The at least one protective layer may be applied to the decorated wood-based mat by conventional means commonly used in the art. Suitable methods for applying the protective layer are, for example, metered size press, curtain coating, spray coating, roll coating, powder coating and the like. However, any other suitable method for forming at least one protective layer on the decorated wood substrate may also be used.

In case the decorative decor is present on only one side of the wood substrate, the method may further comprise step i): a backing layer of any type commonly used in the art is applied to the side of the decorative wood-based panel opposite the decorative trim. Thus, according to one embodiment, in case the at least one decorative finish is present on only one side, the method according to the present invention may further comprise step i): at least one backing layer is applied to the side of the decorative wood-based panel opposite the at least one decorative trim.

In the meaning of the present invention, the term "at least one" backing layer means that step i) may comprise applying one or more backing layers on the side opposite to the at least one decorative finish obtained in step g).

in one embodiment of the invention, step i) may comprise applying a backing layer. Further optionally, step i) may comprise applying two or more backing layers. For example, step i) of the present invention may comprise applying two or three backing layers. Preferably, step h) comprises applying a backing layer.

Step i) may be performed in addition to the optional step h) described above or as a single step, i.e. the process of the invention may further comprise only optional step i). According to one embodiment, the process of the invention further comprises step h) and step i). According to another embodiment, the process of the invention further comprises step h) or step i). The optional process steps h) and/or i) may be carried out in any order known to the person skilled in the art, preferably in an order allowing the most efficient manufacturing process.

according to a preferred embodiment, the backing layer of step i) is applied in the form of paper. The paper may have a weight in the range of 60-140g/m2, preferably 80-90g/m 2. However, any other paper that can be used as a backing layer for wood-based boards can also be used. The paper may be impregnated/contacted with a thermosetting or binder agent such as melamine-formaldehyde resin, urea-formaldehyde resin, polyester resin, phenol resin, a polyvinyl acetate or acrylic based binder, and/or combinations thereof. The paper may further be applied to the decorative wood-based board by any means known in the art of manufacturing wood-based boards. For example, the paper may be applied under heat and pressure in a short cycle press.

Decorative wood substrate and use

According to one aspect of the present invention, a decorative wood-based board is provided.

The decorative wood substrate comprises

a) A substrate of wood particles and/or fibres as defined herein, and

b) At least one coating on the first and/or reverse side of the solid wood substrate, wherein the coating comprises

i) at least one inorganic particulate filler material as defined herein having a ratio of particle size d80 to particle size d20[ d80/d20] of from 0.5 to 1.0, and

ii) at least one binder as defined herein.

c) At least one decorative finish on the first and/or reverse side of the wood-based panel.

With regard to the definition of wood particles and/or fibres, at least one inorganic particulate filler material, at least one binder and optionally a base binder, additives and compounds and preferred embodiments thereof, reference is made to the statements provided above in discussing the technical details of the process of the invention.

The decorative wood substrate comprises

a) a substrate of wood particles and/or fibres as defined herein, and

b) At least one coating on the first and/or reverse side of the solid wood substrate, wherein the coating comprises

i) At least one inorganic particulate filler material as defined herein having a ratio of particle size d80 to particle size d20[ d80/d20] of from 0.5 to 1.0, and

ii) at least one binder as defined herein.

c) At least one decorative finish on the first and/or reverse side of the wood-based board, preferably obtained by a method comprising the steps of:

a) providing wood particles and/or fibres in dry form or in the form of an aqueous suspension,

b) Providing at least one dry or liquid coating composition comprising at least one inorganic particulate filler material and at least one binder,

c) Forming a wood based mat having a first side and an opposite side from the wood particles and/or fibres provided in step a),

d) Prepressing the wood-based mat of step c) into a prepressed wood-based mat,

e) Applying at least one layer of the at least one dry or liquid coating composition of step b) onto a first and/or opposite side of the pre-pressed wood based mat obtained in step d),

f) hot-pressing the pre-pressed wood-based mat obtained in step e) into a solid wood-based board,

g) Applying at least one decorative finish onto the first and/or reverse side of the wood substrate obtained in step f) by inkjet printing, by rotogravure printing, by applying decorative paper, decorative foil or a liquid coating.

the decorative wood substrate is preferably a fiberboard product, more preferably a High Density Fiber (HDF) board, a Medium Density Fiber (MDF) board, a Low Density Fiber (LDF) board, a particle board, an Oriented Strand Board (OSB), a hardboard, or a thermal insulation board.

the decorative wood substrate of the present invention may be a single-layer or multi-layer wood substrate. If the decorative wood-based board is a multi-layer board, the board may be a three-layer or five-layer wood-based board. For example, the wood-based board is a single-layer wood-based board.

In one embodiment, the at least one coating preferably at least partially penetrates into the surface of the wood substrate. Preferably, therefore, the at least one coating layer cannot be removed from the surface of the wood substrate without damaging the surface of the decorative wood substrate.

The decorative wood-based panel of the present invention comprises a substrate of wood particles and/or fibers having a first side and an opposite side. The base of wood particles and/or fibres serves as a support for at least one coating on the first and/or opposite side of the wood-based board. Thus, the wood based board preferably comprises, more preferably consists of, a substrate of wood particles and/or fibres having a first side and an opposite side and at least one coating layer in contact with the first and/or opposite side of the substrate of wood particles and/or fibres.

in one embodiment of the invention, the at least one decorative finish is present on at least one coating on the first and/or opposite side of the wood substrate.

According to another embodiment of the invention, the at least one decorative finish is present on one side of the wood-based board and the at least one coating layer is present on the opposite side of the wood-based board and represents or is part of the backing layer.

the inventors have surprisingly found that if the coating is present on the side opposite to the side comprising the decorative finish, it is not important or less important to apply the backing layer as defined in optional step i). In this case, the coating on the opposite side of the decorative trim serves as or is part of the backing layer and imparts improved mechanical properties, in particular tensile strength, to the decorative wood-based board.

The at least one inorganic particulate filler material preferably has

i) < particle size d98 of 500 μm,

ii) a particle size d80 of 0.1 to 250 μm,

iii) a median particle size d50 of from 0.1 to 150 μm, and

iv) a particle size d20 of 0.1 to 50 μm.

It will be appreciated that the wood-based board is particularly advantageous in terms of its surface characteristics, such as optical properties and surface smoothness. In this respect, it is noted that advantageous surface properties apply only to one side of the wood substrate which has been coated according to the method of the invention.

In one embodiment, the surface of the coated side of the decorative wood substrate preferably has

i) according to ISO R457(Tappi452) and DIN 6167, brightness of 50-100%,

ii) a yellowness of 2 to 70% according to ISO R457(Tappi452) and DIN 6167,

iii) L from 50 to 100 according to DIN EN ISO 11664-4:2012,

iv) a according to DIN EN ISO 11664-4:2012, -5 to 10, and

v) b according to DIN EN ISO 11664-4:2012, 0 to 30.

Additionally or alternatively, the surface of the coated side of the decorative wood substrate has

i) A maximum roughness amplitude Sz of 20-800 μm,

ii) an arithmetic average roughness Sa of 2 to 80 μm, and

iii) a root mean square roughness Sq of 2-20 μm.

in one embodiment, the surface of the coated side of the decorative wood substrate preferably has

i) According to ISO R457(Tappi452) and DIN 6167, brightness of 50-100%,

ii) a yellowness of 2 to 70% according to ISO R457(Tappi452) and DIN 6167,

iii) L from 50 to 100 according to DIN EN ISO 11664-4:2012,

iv) a according to DIN EN ISO 11664-4:2012, -5 to 10, and

v) b according to DIN EN ISO 11664-4:2012, 0 to 30,

And

i) a maximum roughness (roughness average) amplitude Sz of 20-800 μm,

ii) an arithmetic average roughness Sa of 2 to 80 μm, and

iii) a root mean square roughness Sq of 2-20 μm.

According to a preferred embodiment, the at least one inorganic particulate filler material has

i) < particle size d98 of 500 μm,

ii) a particle size d80 of 0.1 to 250 μm,

iii) a median particle size d50 of from 0.1 to 150 μm, and

iv) a particle size d20 of 0.1 to 50 μm,

and the surface of the coated side of the decorative wood substrate has

i) According to ISO R457(Tappi452) and DIN 6167, brightness of 50-100%,

ii) a yellowness of 2 to 70% according to ISO R457(Tappi452) and DIN 6167,

iii) L from 50 to 100 according to DIN EN ISO 11664-4:2012,

iv) a according to DIN EN ISO 11664-4:2012, -5 to 10, and

v) b according to DIN EN ISO 11664-4:2012, 0 to 30,

And

i) A maximum roughness amplitude Sz of 20-800 μm,

ii) an arithmetic average roughness Sa of 2 to 80 μm, and

iii) a root mean square roughness Sq of 2-20 μm.

According to one embodiment, the surface of the coated side of the decorative wood substrate has a contact angle in the range of 5 ° to 80 °, more preferably in the range of 8 ° to 60 °, and most preferably in the range of 8 ° to 50 °. The "contact angle" in the meaning of the present invention is the angle at which a liquid meets a solid surface. This contact angle can be used to quantify the wettability of the surface. "wettability" in the meaning of the present application is the ability of a liquid to remain in contact with a solid surface. A low contact angle generally corresponds to a high wettability of the surface.

The decorative wood-based board of the present invention is particularly characterized by high mechanical properties such as flexural strength and elastic modulus, internal bond strength and thickness swelling.

The decorative wood-based board of the present invention is particularly characterized by high bending strength. Preferably, the decorative wood-based panel has a flexural strength of ≧ 5N/mm2, preferably 10-50N/mm2 and most preferably 15-45N/mm 2. Unless otherwise stated, the flexural strength is determined in accordance with DIN EN 310.

Additionally or alternatively, the decorative wood-based panel of the present invention exhibits a characteristic of high elastic modulus. Preferably, the decorative wood substrate has an elastic modulus of 500N/mm2 or more, preferably 1000-. Unless otherwise stated, the modulus of elasticity is determined in accordance with DIN EN 310.

Additionally or alternatively, the decorative wood-based panel of the present invention exhibits a high internal bond strength. Preferably, the decorative wood-based panel has an internal bond strength of ≧ 0.10N/mm2, preferably 0.2-1.4N/mm2 and most preferably 0.4-1.2N/mm 2. Unless otherwise stated, the internal bond strength is determined in accordance with DIN EN 319. It is understood that this internal bond strength may also be referred to as transverse direction tensile strength.

Additionally or alternatively, the decorative wood-based panel of the present invention exhibits a characteristic of high thickness swelling. Preferably, the decorative wood substrate has a thickness swell of ≦ 20%, more preferably 2.0-15.0% and most preferably 4.0-10% after 24 hours of water storage. Unless otherwise stated, the thickness expansion is determined in accordance with DIN EN 317.

Additionally or alternatively, the decorative wood-based panel of the present invention exhibits a characteristic of high brightness. Preferably, the decorative wood substrate has a brightness of at least 50%, more preferably at least 65%, even more preferably at least 75% and most preferably at least 80%. Unless otherwise stated, the brightness is determined in accordance with ISO R457(Tappi452) and DIN 6167.

For example, the decorative wood substrate has a flexural strength of 5N/mm2 or more, preferably 10 to 50N/mm2 and most preferably 15 to 45N/mm 2; or the elastic modulus is more than or equal to 500N/mm2, preferably 1000-; or an internal bond strength of 0.10N/mm2 or more, more preferably 0.2-1.4N/mm2 and most preferably 0.4-1.2N/mm 2; or a thickness swell after 24 hours water storage of 20% or less, more preferably 2.0 to 15.0% and most preferably 4.0 to 10%; or a brightness of at least 50%, more preferably at least 65%, even more preferably at least 75% and most preferably at least 80%.

Alternatively, the decorative wood-based board has a bending strength of 5N/mm2 or more, preferably 10-50N/mm2 and most preferably 15-45N/mm 2; and the elastic modulus is equal to or more than 500N/mm2, preferably 1000-; and an internal bond strength of 0.10N/mm2 or more, more preferably 0.2-1.4N/mm2 and most preferably 0.4-1.2N/mm 2; and a thickness swell after 24 hours water storage of 20% or less, more preferably 2.0 to 15.0% and most preferably 4.0 to 10%; and a brightness of at least 50%, more preferably at least 65%, even more preferably at least 75% and most preferably at least 80%.

Further, the decorative wood substrate of the present invention preferably exhibits at least one coated side having a high surface density. Thus, in one embodiment, the decorative wood substrate comprises at least one coated side of the decorative wood substrate having a surface density of 900-. The surface density of the decorative wood-based board may be determined by any means known in the art for measuring density properties (profiles) of wood-based boards. For example, a feed rate of 0.5mm/s, an incremental parameter of 20 μm, an X-ray operating voltage of 40kV, and a sample size of 250mm2 can be used for measurement with a raw density characterization analyzer.

In one embodiment, the decorative wood-based panel of the present invention has a thickness of 0.2 to 300.0mm, preferably 2.0 to 40.0mm and most preferably 4.0 to 20 mm.

In case the at least one decorative finish of step g) is performed by inkjet printing and/or rotogravure printing, the printed surface of the decorative wood substrate preferably has a specific print gloss. According to one embodiment, the cyan, magenta, yellow and/or black ink present on the decorative wood substrate preferably has a print gloss in the range of 1-90%, more preferably 1-70% and most preferably 10-50%. Unless otherwise stated, the print gloss is according to standard EN ISO 8254-1: 2003. Additionally or alternatively, the printed surface of the decorative wood substrate preferably has a specific ink density. In the meaning of the present application, the "ink density" is a calculated value which can be obtained by measuring the reflected light of a printed substrate at a specific angle (typically 90 °) when the printed substrate is irradiated with a light source from a different angle (typically 45 °). The term "ink density" and the means for measuring it are well known in the art. Preferably, the cyan, magenta, yellow and/or black ink present on the decorative wood substrate has an ink density in the range of 0.1-10, more preferably 0.2-5, most preferably 0.3-1.2.

According to one embodiment, the decorative wood substrate further comprises

d) at least one protective layer and/or at least one decorative finish on the at least one decorative finish

e) In case the at least one decorative finish is present on only one side, the at least one backing layer, preferably in the form of paper, on the side of the decorative wood substrate opposite the at least one decorative finish.

The decorative wood substrate further comprises

d) At least one protective layer and/or at least one decorative finish on the at least one decorative finish

e) At least one backing layer on the side of the decorative wood substrate opposite the at least one decorative finish, with the at least one decorative finish present on only one side

preferably obtained by a process comprising the further steps of:

h) applying at least one protective layer to the at least one decorative finish obtained in step g), and/or

i) In the case where the at least one decorative finish is present on only one side, at least one backing layer is applied on the side of the decorative wood substrate opposite the at least one decorative finish.

According to a preferred embodiment, the at least one protective layer d) comprises a transparent non-thermoplastic resin, preferably selected from urea-formaldehyde resins, melamine resins, epoxy resins and mixtures thereof.

According to a preferred embodiment, the backing layer e) is paper. The paper may have a weight in the range of 60 to 140g/m2, preferably 80 to 90g/m 2. However, any other paper that can be used as a backing layer for wood-based boards can also be used.

according to another aspect, the present invention relates to the use of at least one dry or liquid coating composition as defined herein for the in-line coating of decorative wood substrates. With regard to the definition of at least one dry or liquid coating composition comprising at least one inorganic particulate filler material and at least one binder, and preferred embodiments thereof, reference is made to the statements provided above in discussing the technical details of the process of the present invention.

"in-line" coating or process in the meaning of the present invention refers to a process wherein the coating step and the pre-pressing and hot-pressing steps are placed in series, especially horizontally in series. In other words, the at least one dry or liquid coating composition comprising at least one inorganic particulate filler material and at least one binder is applied onto the first and/or opposite side of the pre-pressed wood based mat, i.e. after pre-pressing but before hot-pressing the coated pre-pressed wood based mat to form a solid wood based board.

According to another aspect of the present invention there is provided the use of at least one dry or liquid coating composition as defined herein for improving the mechanical properties and in particular the bending strength, the elastic modulus, the internal bond strength and/or the thickness swell of a decorative wood substrate.

According to another aspect of the present invention there is provided the use of a decorative wood-based panel as defined herein in flooring applications, furniture, walls (preferably wall panels), roof panels, display cases, storage units, loudspeakers (preferably loudspeaker enclosures) and shop accessories.

The scope and benefits of the present invention will be better understood by referring to the following examples, which are intended to illustrate some embodiments of the invention and are not limiting.

Drawings

FIG. 1: brightness CIE L of the surface of the medium density fiberboard coated according to the method of the present invention.

FIG. 2: contact angle between water and the surface of a medium density fiberboard coated according to the method of the present invention after a wetting time of six seconds.

FIG. 3: the contact angle between water and the surface of a medium density fiberboard coated according to the method of the present invention was changed over a period of six seconds.

FIG. 4: the raw density characteristics of the surface of a medium density fiberboard coated according to the method of the present invention.

FIG. 5: the overall raw density of the surface of a medium density fiberboard coated according to the method of the present invention.

FIG. 6: the brightness CIE L of the coated surface of the medium density fiberboard modified with 50g/m2 white decorative paper according to the method of the present invention.

FIG. 7: the brightness CIE L of the coated surface of the medium density fiberboard modified with 60g/m2 white decorative paper according to the method of the present invention.

FIG. 8: the brightness CIE L of the coated surface of the medium density fiberboard modified with 66g/m2 white decorative paper according to the method of the present invention.

FIG. 9: according to the method of the present invention, the print gloss of cyan (C), magenta (M), yellow (Y) and black (K) colors printed by inkjet printing on the coated surface of the medium density fiberboard.

FIG. 10: according to the method of the present invention, ink densities of cyan (C), magenta (M), yellow (Y) and black (K) colors are printed by ink-jet printing on the coated surface of a medium density fiberboard.

Detailed Description