TECHNICAL FIELD

The present embodiments generally relate to composite products, and in particular to such composite products comprising a solid wood component coated with a composite material and a method of producing such composite products.

BACKGROUND

Many wood species that are untreated are very susceptible to influences caused by the external environment Untreated wood that is exposed to moisture and/or soil for sustained periods of time will become weakened by attacks by microorganisms and/or insects, it is therefore important to treat the less durable wood in order to increase its resistance to moisture and attacks by microorganisms and/or insects. In addition, wood, which is exposed to ultra violet (UV) radiation, is susceptible to discoloration and deterioration.

There are a number of different treatments to increase the resistance of wood, including chemical treatment with, for instance, fungicides and heat treatment to thermally modify the wood and remove certain organic compounds found in the wood.

Other known methods include applying a layer of polyvinyl chloride (PVC) polymer on or around a solid wood product as described in WO 2007/057029 or coating a solid wood product with a layer of a composite material comprising thermally modified cellulosic material and a polymer, such as polyethylene terephthalate (PET), polyamide (PA), poly(methyl methacrylate) (PMMA), polypropylene (PP) or high density polyethylene (HD-PE), as described in WO 2016/181258.

Such coatings of solid wood products may, however, be sensitive to delamination caused by, for instance, a shift in temperature together with non-matched thermal expansions of the coating and the wood and/or by moisture. Delamination of the coating not only deteriorates the appearance of the product but also exposes the wood to moisture and/or soil that may damage or weaken the wood over time.

WO 2016/105209 discloses a construction element comprising an all-wood core having a protective coating continuously applied to the outer surface of the core. The protective coating comprises at least one layer of a mixture of thermoplastic and wood fiber. A method for manufacturing a construction element with protective coating is also disclosed.

There is, thus, a need for a composite product comprising a wood core and a composite coating that reduces the risk of delamination of the composite coating.

SUMMARY

It is a general objective to reduce delamination of coated solid wood products. This and other objectives are met by embodiments of the present invention.

The present invention is defined in the independent claims. Further embodiments of the invention are defined in the dependent claims. An aspect of the invention reiates to a composite product comprising a solid wood component and a coating layer of a composite material on at least one side of the solid wood component The composite material comprises ceiluiosic material and at least one polymer. An edge seal is applied to a short end of the solid wood component and to at least a short end of the coating layer. The edge seal is attached to the short end of the solid wood component and to at least the short end of the coating layer and forms, with the coating layer, a protective barrier for the solid wood component.

Another aspect of the invention relates to a method of producing a composite product The method comprises extruding a composite material on at least one side of a solid wood component to form a coating layer on the at least one side. The composite material comprises ceiluiosic material and at least one polymer. The method also comprises applying an edge seal to a short end of the solid wood component and to at least a short end of the coating layer. The edge seal is attached to the short end of the solid wood component and to at least the short end of the coating layer and forms, with the coating layer, a protective barrier for the solid wood component The present invention solves delamination problems in composite products, or at least reduces the risk of delamination, by applying an edge seal to the solid wood component of the composite products. This edge seal can be added to the solid wood component as a part of the process of applying the protective composite coating layer onto the solid wood component Hence, the resulting composite product will be protected from the environment and have a reduced risk of delamination of the protective composite coating layer.

BRIEF DESCRIPTION OF THE DRAWINGS The embodiments, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawings, in which:

Fig. 1 A is a cross-sectional view of a composite product according to an embodiment; Fig. 1 B is a cross-sectional view of the composite product taken along the line A-A in Fig. 1 A;

Fig. 2 is a flow chart illustrating a method of producing a composite product; and

Fig. 3 is a flow chart illustrating an embodiment of applying the edge seal in Fig. 2.

DETAILED DESCRIPTION

The present embodiments generally relate to composite products, and in particular to such composite products comprising a solid wood component coated with a composite material and a method of producing such composite products.

Many wood products are protected by polymer-based coating layers, such as thermoplastic or composite coatings, to protect the wood core from the external environment, including atacks by microorganisms and/or insects, and UV radiation. However, such composite products are sensitive to delamination or creep, in particular at the unprotected edges or short ends of the composite products. Delamination causes the protective polymer-based coating layer to separate from the wood core, in particular at the edges. As a consequence of such a delamination, the wood core is exposed to the environment and may thereby be susceptible to attacks and environmental conditions that negatively affect the wood quality. Delamination of the protective polymer-based coating layer may be due to various reasons, including a shift in ambient temperature causing thermal expansion of the coating layer relative to the wood core, and/or moisture, such as due to precipitation, exposure to cleaning agents, or humidity, entering between the coating layer and the wood core causing a swell of the wood core. The present invention solves delamination problems in composite products, or at least reduces the risk of delamination, by applying an edge seal to the solid wood component or core of the composite products. This edge seal can be added to the solid wood component as a part of the process of applying the protective composite coating layer onto the solid wood component Hence, the resulting wood product will be protected from the environment and have a reduced risk of delamination of the protective composite coating layer.

An aspect of the invention relates to a composite product 1, see Figs. 1A and 1B. The composite product 1 comprises a solid wood component 10 and a coating layer 20 of a composite material on at least one side 12, 14, 18, 18 of the solid wood component 10. The composite material comprises cellulosic material and at least one polymer, such as at least one thermoplastic polymer. The composite product 1 also comprises an edge seal 30, 40 applied to a short end 11, 13 of the solid wood component 10 and to at least a short end 22, 24 of the coating layer 20. The edge seal 30, 40 is attached to the short end 11 , 13 and to at least the short end 22, 24 of the coating layer 20 and forms, with the coating layer 20, a protective barrier for the solid wood component 10.

According to the present invention, an edge seal 30, 40 is applied to at least one short end 11 , 13 of the solid wood component 10 and at least one short end 22, 24 of the coating layer 20. This edge seal 30, 40 forms a protective barrier for the solid wood component 10 together with the coating layer 20 of the composite material. The formed barrier thereby protects the solid wood component 10 from influences caused by the external environment, such as moisture, atacks by microorganisms and/or insects, and/or UV radiation.

The edge seal 30, 40 forms a protective end coating on the short end 11, 13 of the solid wood component 10 and prevents or at least significantly restricts moisture from penetrating in between the coating layer 20 and the solid wood component 10 at the associated short end 11, 13. The edge seal 30, 40 in additional restricts any thermal expansion of the coating iayer 20 and thereby also reduces the risk of delamination of the coating Iayer 20 due to temperature shifts. The edge seal 30, 40 preferably has a size larger fhan a size of the short end 11 , 13 of the solid wood component 10. Hence, dimensions of the edge seal 30, 40, such as length and height, are preferably larger than the corresponding dimensions of the short end 11, 13 of the solid component 10 as shown in Fig. 1 A to also cover the end parts or short ends 22, 24 of the coating Iayer 20, Correspondingly, the overall shape of the edge seal 30, 40 preferably corresponds to the shape of the short end 11, 13 of the solid wood component 10, i.e., if the solid wood component 10 has a quadratic or rectangular cross- sectional shape, the edge seal 30, 40 preferably has a quadratic or rectangular shape. In other words, the edge seal 30, 40 is preferably dimensioned and designed to cover at least the short end 11, 13 of the solid wood component 10 and the corresponding short end 22, 24 of the coating layer 20.

In an embodiment and as more clearly seen in Fig. 1B being a cross-sectional view of Fig. 1A taken along the line A-A, the composite product 1 preferably comprises the coating layer 20 on all sides 12, 14, 16, 18 of the solid wood component 10. Hence, in an embodiment, the coating layer 20 is applied onto ail sides 12, 14, 16, 18 of the solid wood component 10 except the short ends 11, 13. These sides 12, 14, 16, 18 are preferably longitudinal or oblong sides 12, 14, 16, 18 of the solid wood component 10 to indicate that they generally have a comparatively longer length than width as shown in Figs. 1A and 1 B.

The solid wood component 10 generally has an elongated and oblong form with two short ends 11, 13 at either end of the solid wood component 10, A side 12, 14, 16, 18 of the solid wood component 10 as used herein is a side 12, 14, 16, 18 of the solid wood component 10 extending between the two short ends 11, 13. The number of such sides 12, 14, 16, 18 of the solid wood component 1G depends on the cross-sectional configuration of the solid wood component 10. For instance, a solid wood component 10 having a quadratic or rectangular cross-section generally has four longitudinal sides 12, 14, 16, 18, a solid wood component 10 having a triangular cross-section typically has three longitudinal sides, and a solid wood component 10 having a circular cross-section has one longitudinal side corresponding to the lateral surface of the solid wood component 10.

In a particular embodiment, the solid wood component 10 has a rectangular or quadratic general cross- sectional shape as shown in Fig. 1B and thereby has four longitudinal sides 12, 14, 16, 18. The embodiments are, however, not limited thereto. The solid wood component 10 may have other cross- sectional shapes with more than or fewer than four (longitudinal) sides 12, 14, 16, 18. According to the invention, the coating layer 20 could be applied to all or a portion of the sides of the solid wood component 10.

In an embodiment, the edge seal 30, 40 is a first edge seal 30 applied to a first short end 11 of the solid wood component 10 and to at least a first short end 22 of the coating layer 20. The composite product 1 further comprises a second edge seal 40 applied to a second short end 13 of the solid wood component 10 and to at least a second short end 24 of the coating layer 20. The second edge seal 40 is atached to the second short end 13 and to at least the second short end 24 of the coating layer 20 and forms, with the coating layer 20 and the first edge seal 30, the protective barrier for the solid wood component 10. Hence, in a preferred embodiment, a respective edge seal 30, 40 is applied to each short end 11, 13 of the solid wood component 10 as shown in Fig. 1A. In a particular embodiment, a respective edge seal 30, 40 is applied to each short end 11, 13 of the solid wood component 10 and the coating layer 20 is applied on all four (longitudinal) sides 12, 14, 16, 18 of the solid wood component 10. In such a particular embodiment, the edge seals 30, 40 and the coating layer 20 form a protective enclosure around the entire solid wood component 10. This means that all sides 12, 14, 16, 18 and the short ends 11, 13 of the solid wood component 10 are thereby protected either by the coating layer 20 or by an edge seal 30, 40.

According to an embodiment, the edge seal 30, 40 is sprayed, painted or spread onto the short end 11, 13 of the solid wood component 10 and onto at ieast the short end 22, 24 of the coating layer 20. For instance, a liquid, cream or paste-based edge seal material could be sprayed, painted or spread onto the short end 11, 13 of the solid wood component 10 and onto at Ieast the short end 22, 24 of the coating layer 20. The edge seal 30, 40 is sprayed, painted or spread, onto the short end 22, 24 of the coating layer 20, In addition onto the short end 11, 13 of the solid wood component 10, It is also possible to spray, paint or spread the edge seal 30, 40 at Ieast partly onto the main surface(s) of the coating layer 20, i.e., the surface(s) of the coating layer 20 as applied onto the at Ieast one side 12, 14, 16, 18 of the solid wood component 10.

In an embodiment, the edge seal 30, 40 is painted or spread onto the short end 11, 13 of the solid wood component 10 and onto at Ieast the short end 22, 24 of the coating layer 20. For instance, the edge seal 30, 40 could be painted onto the short end 11, 13 of the solid wood component 10 and onto at Ieast the short end 22, 24 of the coating layer 20. Alternatively, the edge seal 30, 40 is spread onto the short end 11, 13 of the solid wood component 10 and onto at Ieast the short end 22, 24 of the coating layer 20.

In an embodiment, the edge seal 30, 40 is selected from the group consisting of a polish seal, a lacquer seal, a paint-based seal (such as an acrylic paint-based seal or a polyurethane (PU) paint-based seal), a sealing paste, a sealing adhesive (such as a PU-based adhesive) and a silicon-based seal applied, e.g., sprayed, painted or spread, to the short end 11, 13 of the solid wood component 10 and to at Ieast the short end 22, 24 of the coating layer 20, see Fig, 1A. In this embodiment, the edge seal 30, 40 is thereby applied to the short end 11, 13 of the solid wood component 10 and to at least the short end 22, 24 of the coating layer 20 as shown in Fig. 1A to form, together with the coating layer 20, a protective barrier for the solid wood component 10.

In a particular embodiment, the edge seal 30, 40 is selected from the group consisting of a lacquer seal, a sealing paste, a sealing adhesive and a silicon-based seal and more preferably a lacquer seal or a PU seal. In another particular embodiment, the edge seal 30, 40 is selected from the group consisting of a lacquer seal and a paint-based seal. In a preferred embodiment, the edge seal 30, 40 is a paint-based seal. Illustrative, but non-limiting, examples of such paint-based seals include an acrylic paint-based seal and a PU paint-based seal. In another embodiment the edge seal 30, 40 is a lacquer seal, In these embodiments, the edge seal 30, 40 is preferably sprayed, painted or spread, such as painted or spread, onto the short end 11 , 13 of the solid wood component 10 and to at least the short end 22, 24 of the coating layer 20 to form the edge seal 30, 40 in the form of a paste, cream or liquid. Thus, in these embodiments, a lacquer edge seal material or a paint-based edge seal material in the form of a paste, cream or liquid is preferably sprayed, painted or spread, such as painted or spread, onto the short end 11 , 13 of the solid wood component 10 and onto at least the short end 22, 24 of the coating layer 20 to form the edge seal 30, 40 in the form of a paste, cream or liquid.

Particular examples of such pastes, creams or liquids that could be applied, e.g., sprayed, painted or spread, to the short end 11, 13 of the solid wood component 10 and to at least the short end 22, 24 of the coating layer 20 include shellac, nitrocellulose lacquer, pre-catalyzed lacquer, conversion varnish, acid-catalyzed lacquer, alkyd varnish, polyurethane oil based varnish, polyurethane water-based varnish and epoxy resin.

The cellulosic material of the coating layer 20 preferably comprises natural fibers,

The natural fibers used in accordance with the present invention are natural fibers that contain cellulose and, in many cases, lignin and/or hemicelluloses. The natural fibers may be produced by chemical pulping, mechanical pulping, chemo-mechanical pulping or mechanical milling/crushing of cellulosic or lignocellulosic raw materials. They are, typically, wood fibers produced by chemical pulping, mechanical pulping, chemo-mechanical pulping or mechanical milling/crushing of softwood or hardwood. Examples of such pulps are chemical pulp, such as sulfate or sulfite pulp, dissolving pulp, thermomechanical pulp (TMP), high temperature thermomechanical pulp (HTMP), mechanical fiber intended for medium density fiberboard (MDF-fiber), chemo-thermomechanical pulp (CTMP), high temperature chemo- thermomechanical pulp (HTCTMP), and combinations thereof. The fibers can also be produced by other methods such as steam explosion pulping, milling/crushing and/or from other cellulosic or lignocellulosic raw materials such as flax, jute, hemp, kenaf, bagasse, coton, bamboo, straw or rice husk. It is also possible to use cellulosic material that is a mixture of fibers from different raw materials, such as a mixture of wood and any of the materials mentioned above.

The cellulosic material may alternatively consist of, or may comprise, microfibriiiated cellulose.

The celiuiosic material may alternatively consist of, or may comprise, milled wood fibers, In an embodiment, the celiuiosic material is thermally modified celiuiosic material, i.e,, the celiuiosic material has been thermally modified, in an embodiment, all celiuiosic material is thermally modified celiuiosic material. In another embodiment, at least a part of the celiuiosic material is thermally modified celiuiosic material. Thus, in an embodiment, the composite material comprises thermally modified celiuiosic material and non-thermally modified celiuiosic material.

Microfibriiiated cellulose (MFC) as used herein means a cellulose particle, fiber or fibril having a width or diameter of from 20 nm to 1000 nm.

Various methods exist to make MFC, such as single or multiple pass refining, pre-hydrolysis followed by refining or high shear disintegration or liberation of fibrils. One or several pre-treatment steps Is usually required in order to make MFC manufacturing both energy efficient and sustainable. The cellulose fibers of the pulp used when producing MFC may, thus, be native or pre-treated enzymatically or chemically, for example to reduce the quantity of hemicellulose and/or lignin. The cellulose fibers may be chemically modified before fibrillation, wherein the cellulose molecules contain functional groups other (or more) than found in the original cellulose. Such groups include, among others, carboxymethyi (CM), aldehyde and/or carboxyl groups (cellulose obtained by N-oxyl mediated oxidation, for example "TEMPO"), or quaternary ammonium (cationic cellulose). After being modified or oxidized in one of the above-described methods, it is easier to disintegrate the fibers into MFC. MFC can be produced from wood cellulose fibers, both from hardwood or softwood fibers. It can also be made from microbial sources, agricultural fibers, such as wheat straw pulp, bamboo, bagasse, or other non-wood fiber sources. It can be made from pulp, Including pulp from virgin fiber, e.g., mechanical, chemical and/or thermomechanical pulps. It can also be made from broke or recycled paper,

In an embodiment, the composite material comprises less than 50% by weight of the ceilulosic material. In a particular embodiment, the composite material comprises less than 45 % by weight of the ceilulosic material, preferably less than 30 % by weight of the ceilulosic material, and more preferably less than 25 % by weight of fhe ceilulosic maferial. If is also possible to have a composite material comprising even less ceilulosic material, such as less than 20 % by weight of the ceilulosic material or less than 15 % by weight of the ceilulosic material. In an embodiment, the composite material comprises at least 1 % by weight of the ceilulosic material, preferably at least 2.5 % by weight of the ceilulosic material, and more preferably at least 5 % by weight of the ceilulosic material. In particular embodiment, the composite material comprises between 15 and 45 % by weight of the ceilulosic material, preferably between 15 and 30 % by weight of the ceilulosic material, and more preferably between 15 and 25 % by weight of the ceilulosic material.

In an embodiment, the ceilulosic material in the composite material comprises ceilulosic fibers having a length weighted average fiber length of up to 5 mm, preferably of up to 4 mm, more preferably of up to 3 mm, and most preferably up to 2 mm. in a particular embodiment, the length weighted average fiber length is equal to or below 1.7 mm, such as equal to or below 1.5 mm, preferably equal to or below 1 mm.

Length of fibers, such as ceilulosic fibers, as referred to herein, is length weighted average fiber length. Length weighted average fiber length is calculated as the sum of individual fiber lengths squared divided by the sum of the individual fiber lengths as described in e.g., IS016065-1 or ISO 16065-2.

In an embodiment, the ceilulosic material may be in the form of a powder. For instance, the ceilulosic material may comprise ceilulosic fibers that have been mechanically treated to a powder. The size of the ceilulosic material is of importance in order to be able to achieve composite material where the ceilulosic material is evenly distributed, it was found that if the ceiiuiosic material is in the form of a powder it is easy to achieve a good dispersion and mixture with the polymer. In an embodiment the powder particles have an average size (diameter) of up to 5 mm, preferably of up to 4 mm, more preferably of up to 3 mm, and most preferably up to 2 mm. in a particular embodiment the average size (diameter) is equal to or below 1.7 mm, such as equal to or below 1.5 mm, preferably equal to or below 1 mm, or even smaller.

In an embodiment, the polymer of the composite material is a thermoplastic polymer. Non-limiting, but illustrative, examples of such thermoplastic polymers include polyethylene terephthalate (PET), polystyrene (PS), polyamide (PA), poly(methyl methacrylate) (PMMA), polypropylene (PP), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), styrene-acrylonitrile (SAN), polyacryiic acid (PAA), polylactic acid (PLA), polycarbonate (PC) and polyethylene (PE), such as high-density PE (HDPE) or low-density PE (LORE), and combinations thereof, preferably PET.

It is also possible to have a composite material comprising two or more different polymers, such as thermoplastic polymers, such as a mixture of two or more of PET, PS, PA, PMMA, PP, PVC, ABS, SAN, PAA, PLA, PC and PE.

In a particular embodiment, the polymer is a high melt polymer having a melting temperature above 180°C, preferably above 200 ^° C. Such high melt polymers are in particular useful if the solid wood component 10 of the composite product 1 is a thermally modified solid wood component 10 since such a thermally modified solid wood component 10 is more temperature resistant as compared to normal kiln dried solid wood components. This higher temperature resistance in turn enables using higher temperatures when applying the composite material onto the solid wood component 10, such as in an extruder. In an embodiment, the solid wood component 10 is a thermally modified solid wood component 10.

In an embodiment, the composite material comprises thermally modified cellulosic material and the at least one polymer, Thermally modified wood as used herein, such as the thermally modified solid wood component 10 and/or thermally modified ceiiuiosic material, is wood or ce!lu!osic material at which the composition of the cell wall material and its physical properties are modified by the exposure of temperature higher than 160 °C and conditions of reduced oxygen availability. The wood or ceiiuiosic material is altered in such way that at least some of the properties are permanently affected through the cross section of the solid wood component or cellulosic material. In particular, the thermally modified wood has a lower number of hydroxyl groups (OH) as compared to non-thermally modified wood. In a particular embodiment thermally modified wood is as defined in SID-CEN/TS 15679:2008 Thermally modified Timber - Definitions and characteristics.

Thermally modified wood is wood that has been modified by a controlled pyrolysis process of wood being heated, preferably in the absence of oxygen or at least in reduced oxygen atmosphere. Such a heat treatment induces chemical changes to the chemical structures of cell wall components, including lignin, cellulose and hemicellulose, in the wood resulting in increased durability. Low oxygen content during the heating process prevents the wood from burning at these high temperatures. Various heat treating processes are known to produce thermally modified wood including Westwood process, Plato process, Retificaiion process, Les Bois Perdure process, Oil heat treatment and THERMOWOOD® process. The heat treatment process removes certain organic compounds, often denoted volatile organic compounds (VOCs), which reduces the possibility for fungi and rot to thrive on the wood. In addition, the chemical changes to the chemical structures of the cell wall components make these less appetizing to fungi and insects. The heat treatment may, additionally, improve properties of the wood with respect to moisture, e.g,, lower equilibrium moisture content, less moisture deformation and improved weather resistance.

The heat treatment is preferably performed for at least 5 hours, preferably at least 15 hours, more preferably at least 20 hours, such as at least 25 hours or even longer, such as at least 30 hours or at least 35 hours.

The heat treatment applied to the solid wood component 10 may also, or alternatively, be applied to the celiuiosic material in the composite material of the coating layer 20 and/or of the edge seal 30, 40,

In an embodiment, the coating layer 20 comprises a fire retardant, also referred to as flame retardant in the art. Alternatively, or in addition, the solid wood component 10 has been treated with such a fire retardant.

Any fire retardant traditionally used in wood products could be included in the composite material of the coating layer 20 and/or used to treat the solid wood component 10. Illustrative, but non-limiting, examples of fire retardants are based on phosphorus, nitrogen, boron, silica and/or their combinations, for instance, mono-ammonium phosphate, di-ammonium phosphate, ortho-phosphoric acid, ammonium sulphate, borax, boric acid, boric oxide, disodium octoborate, melamine phosphate, etc. The solid wood component 10 of the composite product 1 is an engineered wood component 10, sometimes also referred to as wood core or engineered wood core. The solid wood component 10 can be of any kind of wood, e.g. softwood or hardwood or even bamboo. The solid wood component 10 can be any piece of wood, such as plank or board, including a piece of wood having holes, indentations, protrusions, tongue and grooves or other engineered structures.

The composite product 1 can be used for the production of many different products, such as cladding, decking, window and door profiles, light poles, jetties, joinery, furniture, joists, wail elements, sound barriers, fencing, products used in flooring, parquetry, paneling, etc. Another aspect of the invention relates to a method of producing a composite product 1 , see Fig. 2. The method comprises extruding, in step S1, a composite material on at least one side 12, 14, 16, 18 of a solid wood component 10 to form a coating layer 20 on the at least one side 12, 14, 16, 18. The composite material comprises cellulosic material and at least one polymer, such as at least one thermoplastic polymer. A next step S2 comprises applying an edge seal 30, 40 to a short end 11, 13 of the solid wood component 10 and to at least a short end 22, 24 of the coating layer 20. The edge seal 30, 40 is attached to the short end 11, 13 of fhe solid wood component 10 and to at least the coating layer 20 and forms, with the coating layer 20, a protective barrier for the solid wood component 10.

Hence, in an embodiment, the coating layer 20 is obtained by extruding the composite material onto the solid wood component 10. For instance, the composite material may be fed to an extruder. The solid wood component 10 is conveyed through the extruder while applying a layer of the composite material to form the coating layer 20 on the at least one side 12, 14, 16, 18 of the solid wood component 10 while it is conveyed through the extruder. In an embodiment, step S1 of Fig. 2 comprises extruding the composite material on all (longitudinal) sides 12, 14, 16, 18 of the solid wood component 10 to form the coating layer 20 on all (longitudinal) sides 12, 14, 16, 18. In an embodiment, the edge seal 30, 40 is a first edge seal 30. in such an embodiment, step S2 in Fig. 2 comprises applying the first edge seal 30 to a first short end 11 of the solid wood component 10 and to at least a first short end 22 of the coating layer 20 and a second edge seal 40 to a second short end 13 of the solid wood component 10 and to at least a second short end 24 of the coating layer 20. The second edge seal 40 is attached to the second short end 13 of the solid wood component 10 and to at least the second short end 24 of the coating layer 20. The first edge seal 30, the second edge seal 40 and the coating layer 20 form the protective barrier for the solid wood component 10. This embodiment of step S2 is preferably combined with extruding the composite material on all four (longitudinal) sides 12, 14, 16, 18 of the solid wood component, in such a case, the two edge seals 30, 40 and the coating layer 20 form a protective enclosure around the solid wood component 10.

In an embodiment, step S2 in Fig. 2 is performed as shown in Fig. 3. The method continues from step S1 in Fig. 2. A next step S10 comprises applying a polish seal, a lacquer seal, a paint-based seal, a sealing paste, a sealing adhesive or a silicone-based seal onto the short end 11, 13 of the solid wood component 10 and to at least the short end 22, 24 of the coating layer 20, in a particular embodiment, step S10 comprises applying a lacquer seal or a PU seal onto the short end 11, 13 of the solid wood component 10 and to at least the short end 22, 24 of the coating layer 20. In another particular embodiment, step S10 comprises applying the lacquer seal or the paint-based seal to the short end 11, 13 of the solid wood component 10 and to at least the short end 22, 24 of the coating layer 20. In a currently preferred embodiment, step S10 comprises applying the paint-based seal to the short end 11,

13 of the solid wood component 10 and to at least the short end 22, 24 of the coating layer 20. For instance, step S10 could comprise applying an acrylic paint-based seal or a PU paint-based seal to the short end 11, 13 of the solid wood component 10 and to at least the short end 22, 24 of the coating layer 20.

In an embodiment, step S2 in Fig. 2 comprises spraying, painting or spreading the edge seal onto the short end 11, 13 of the solid wood component 10 and onto at least the short end 22, 24 of the coating layer 20. In a particular embodiment, step S2 comprises painting or spreading the edge seal onto onto the short end 11, 13 of the solid wood component 10 and onto at least the short end 22, 24 of the coating layer 20. These embodiments are particular suitable for usage with an edge seal as mentioned above and disclosed In Fig. 3. In such an embodiment step S10 in Fig, 3 comprises spraying, painting or spreading, such as painting or spreading, a polish seal, a lacquer seal, a paint-based seal, a sealing paste, a sealing adhesive or a silicone-based seal onto the short end 11, 13 of the solid wood component 10 and onto at least the short end 22, 24 of the coating layer 20. The embodiments described above are to be understood as a few illustrative examples of the present invention. It will be understood by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the scope of the present invention. In particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible.