Wood element with a coating and method for production of a wood element with a coating, method for production and use of the wood element

Abstract

The invention relates to a wood element (1), in particular a wood element for use as a structural component, having a main body (2) with an at least approximately planar lateral face (21) which is at least partially covered with a polymer coating (3), the polymer coating (3) forming an integral bond with the wood element. According to the invention, the polymer coating (3) has a peel strength of at least 3.0 N / 25mm and at most 15.0 N / 25mm.

Description

[0001] WOODEN ELEMENT WITH A COATING AND METHOD FOR PRODUCING A WOODEN ELEMENT WITH A COATING, METHOD FOR PRODUCING AND USE OF THE WOODEN ELEMENT

[0002] The invention relates to a wooden element, in particular for construction purposes, with a coating and a method for producing such a wooden element.

[0003] Wood, a renewable and CO2-neutral raw material, is becoming increasingly important as a construction material. The mechanical properties of many wood species allow the use of wood elements, for example in the form of solid wood or cross-laminated timber, for structural components. Depending on the application, wood can be used largely untreated as a construction material. This is advantageous because it prevents the release of volatile and potentially hazardous substances over the long service life of the wood element.

[0004] Increasing attention is also being paid to the future dismantling of building elements at the end of their service life. Timber elements are generally very easy to dismantle and dispose of. Composite elements, which have also been treated with chemicals, fare poorly.

[0005] To increase the service life of wooden elements, especially largely untreated wooden elements, in construction, they must be protected from adverse weather influences, particularly during the construction phase. After construction is completed, the wooden elements can be permanently protected, for example by a roof, which significantly increases the service life of untreated wood. To protect such wooden elements from weather influences such as precipitation or UV radiation during the construction phase, for example, before the protective roof is completed, temporary construction phase protection agents are used. Protective films are particularly well known from the state of the art, with which weather-exposed wooden elements are covered during the construction phase. This is associated with a high level of effort, as the films usually have to be cut by hand to the required dimensions.In addition, the protective films can be damaged when walking on them with heavy footwear, which is necessary during the construction phase, thus compromising the protection of the wooden element. The protective films can also slip. Therefore, they are bonded to the wood, usually with adhesive. This makes the protective films irreversible to removal without leaving residue.

[0006] Also known from the state of the art are protective films that are mechanically applied and glued to wooden elements. While this method is faster than manual application, it suffers from the same deficiencies regarding removability.

[0007] The present invention is therefore based on the object of creating an improved wooden element which is not affected by the aforementioned defects or is affected to a significantly lesser extent.

[0008] In particular, the wooden element should be well protected against weather influences during construction phases.

[0009] Furthermore, the wooden element should be suitable for structural construction purposes.

[0010] In addition, the wooden element should be easy to manufacture and largely free of solvents and, in particular, free of household toxins.

[0011] Furthermore, the wooden element should be accessible during the construction phase to the extent usual on construction sites, especially with sturdy footwear.

[0012] The wooden element should also be easy to dismantle or dispose of without leaving any residue.

[0013] A process for producing such a wooden element is also to be created.

[0014] This object is achieved with a wooden element and a method having the features specified in claim 1 and 21, respectively. Advantageous embodiments of the invention are specified in further claims. The wooden element, which is particularly suitable for use as a structural component, has a base body with at least one approximately planar side surface, which is at least partially covered with a polymer coating. The polymer coating forms a material-to-material bond with the wooden element.

[0015] According to the invention, the polymeric coating has a peel strength of at least 3.0 N / 25 mm, preferably at least 3.2 N / 25 mm, particularly preferably at least 3.5 N / 25 mm, and a maximum of 15.0 N / 25 mm, preferably a maximum of 13.7 N / 25 mm, particularly preferably a maximum of 12.5 N / 25 mm. The peel strength is measured with respect to the wood element according to the FINAT FTM1 test method. The peel test is carried out at 300 mm / min, with the adhesive forces being determined after 20 minutes. The beechwood substrate is standardized according to DIN EN 205.

[0016] The polymer coating adheres well to the wood element without the need for adhesive. This reduces material and manufacturing costs. Furthermore, recyclability is improved, as the polymer coating can be removed from the wood element largely without leaving residue. This allows both the wood element and the polymer coating material to be recycled or reused separately, largely without any foreign material.

[0017] The polymer coating protects the wooden element, especially during the construction phase, from damage caused by weathering, walking on it, tools, and other damage mechanisms typical of construction sites.

[0018] The polymer coating adheres well enough to the wooden element that it cannot slip when walked on or exposed to strong winds, for example. This increases safety on the construction site and ensures constant protection of the wooden element through the polymer coating.

[0019] If necessary - for example, at the end of the construction phase - the polymer coating can be removed from the wooden element largely without leaving any residue.

[0020] The polymer coating preferably has a minimum thickness of 10 μm, more preferably 30 μm, and most preferably 50 μm. This low thickness optimizes material costs, and the minimum thickness allows for the necessary mechanical resistance to be achieved.

[0021] Particularly preferably, the polymer coating is made of a material with a melting point between 70°C and 300°C. The material is thus easily processable at temperatures that are easily manageable industrially. The energy required to process the coating material is reduced.

[0022] The polymeric coating preferably comprises a thermoplastic polymer material, preferably a thermoplastic biopolymer, and / or a wood-polymer composite material. The polymeric coating preferably comprises polyethylene, polypropylene, polyurethane, polyester, polyvinyl chloride, polystyrene, polyamide, ethylvinyl acetate, ethylene-vinyl acetate copolymers, and / or ethylene-propylene-diene rubber. Particularly preferably, the polymeric coating comprises a recycled polymer material and / or a compostable polymer material. The polymeric coating preferably comprises mixtures of the aforementioned polymers and / or copolymers and / or terpolymers of the aforementioned polymers. The polymeric coating can thus be produced from numerous materials, enabling optimized properties for the specific application at reduced costs.

[0023] In a further preferred embodiment, the polymeric coating comprises a thermosetting polymer material and / or an elastomer and / or a hotmelt material.

[0024] In a preferred embodiment, the coating is made of a wood-plastic composite material. This allows the wood look of the wooden element to be retained despite the coating.

[0025] The polymer coating is preferably an extrusion product. The polymer coating can thus be produced easily, quickly, and cost-effectively, especially in large quantities. In a preferred embodiment, the polymer coating is produced by co-extrusion. In particularly preferred embodiments according to the invention, the polymer coating is the product of a melt casting process, a casting process, a rolling process, or a combination of the aforementioned processes.

[0026] In a preferred embodiment, the polymer coating comprises several superimposed and bonded layers. This allows for optimization.

[0027] Corona treatment and / or plasma treatment are preferably applied to the polymer coating. This post-treatment optimizes the material properties of the polymer coating.

[0028] In a further embodiment of the invention, the polymer coating is flame-retardant and / or flame-retardant. The polymer coating is preferably UV-resistant, particularly preferably by admixing additives to the coating.

[0029] In a further preferred embodiment, the polymer coating covers the wooden element in strips, with uncoated wooden sections lying between the strips.

[0030] Preferably, the polymeric coating covers at least 70%, more preferably at least 80%, most preferably at least 90% of at least one side surface of the wooden element.

[0031] In a further preferred embodiment, the polymer coating completely covers at least one side surface of the wooden element. In particular, the polymer coating has no openings, pores, or holes extending through to the wooden element. The wooden element is thus optimally protected by the polymer coating.

[0032] In a particularly preferred embodiment, the polymer coating is at least partially optically transparent. Preferably, an inscription and / or a marking and / or a colored symbol is applied to the wooden element, which is visible through the polymer coating. This allows safety or processing instructions to be applied securely and legibly for a long time. In a preferred embodiment, the inscription is printed on the polymer coating. This simplifies printing compared to printing on wood. More preferably, the polymer coating can be colored, allowing for decorative design options. The printing can be produced using printing machines known from the prior art.

[0033] The polymer coating can particularly preferably be removed from the wooden element with at least almost no residue. This improves the recyclability of both the polymer coating material and the uncoated wooden element.

[0034] The wood element is preferably a solid wood, a cross-laminated timber, a multi-layer board, a soft fiberboard, a wood-based panel, or a hardwood, or preferably comprises at least one of the aforementioned materials. The wood element is particularly preferably a wood-based panel, a plasterboard, or a cellulose-based workpiece.

[0035] The coating preferably has a textured surface on the side facing away from the wooden element to increase slip resistance. This can help prevent accidents when walking on construction sites, especially in wet weather.

[0036] In a preferred embodiment, the coating is designed such that knots, cracks, gaps, and other defects and irregularities in the wood element are sealed by the coating. This provides the most vulnerable elements in the wood element with good protection against water and moisture.

[0037] In a preferred embodiment, a fleece or mesh is arranged on the side of the coating facing away from the wooden element. The fleece or mesh is firmly bonded to the coating and / or at least partially embedded in the coating. The coating is preferably free of household toxins, in particular free of household toxins according to Emicode®. The coating particularly preferably achieves class EC1+ according to Emicode®. The coating preferably contains less than 5 percent by weight of volatile substances. The coating therefore poses no health hazard, even if it is left on the wooden element.

[0038] The coating preferably has an sd value between 0.1 and 20 m. The coating is particularly preferably vapor-barrier.

[0039] The wooden element preferably comprises sensors arranged on the planar side surface covered by the coating and encapsulated by the coating. The sensors can measure the material properties and aging of the wooden element and, in particular, predict malfunctions or the need for replacement.

[0040] In a particularly preferred embodiment of the invention, the coating is applied directly to the wooden element without any intermediate layers. The coating thus exhibits the preferred adhesive properties without the use of adhesives.

[0041] Preferably, the polymer coating has improved sound absorption compared to uncoated wood.

[0042] The production of a wooden element according to the invention is preferably carried out by a method also according to the invention.

[0043] The process for increasing the weather resistance of wooden elements, in particular structural elements made of wood, comprises the following process steps:

[0044] - Feeding a wooden element to a coating device;

[0045] - Aligning a flat surface of the wooden element along a

[0046] Coating direction of the coating device;

[0047] - Feeding a polymer material in solid form to the

[0048] coating device;

[0049] - Heating the polymer material; - Feeding the heated polymer material in an at least partially molten state to at least one application element of the coating device;

[0050] - Application of the heated material carried out by the application element

[0051] Polymer material onto the flat surface of the wooden element.

[0052] Preferably, the wooden element is also heated, at least in the area of ​​the flat surface, by the applied heated polymer material.

[0053] In a preferred embodiment, the method additionally comprises the method step:

[0054] - Structuring of the and applied to the wooden element

[0055] Polymer material with a roller, preferably with an embossing roller.

[0056] In a preferred embodiment, the method additionally comprises the method step:

[0057] - Cooling of the wooden element coated with the polymer material.

[0058] When heated, the polymer material exhibits only weak adhesion to the wood element. When cooled, the bond strength is increased.

[0059] The process according to the invention preferably comprises an extrusion process, a co-extrusion process, a melt casting process, a rolling process or a cast film process.

[0060] In a preferred embodiment of the process according to the invention, the polymer material is heated to at least 150°C, preferably at least 165°C, more preferably at least 180°C.

[0061] Preferably, the polymer material is heated to a temperature which is at least 20°C higher than the glass transition temperature of the polymer material.

[0062] The use of a wood element according to the invention for use in the construction sector is also the subject of this invention. In particular, the use of a wood element according to the invention as a structural or decorative building element is the subject of this invention. The invention is explained in more detail below with reference to the drawings. In the drawings:

[0063] Fig. 1a a base body 2 of a wooden element with a planar side surface 21;

[0064] Fig. ib a wooden element 1 according to the invention with a coating 3;

[0065] Fig. 2 shows a device for producing a wooden element according to the invention.

[0066] Fig. 1a shows the base body 2 of a wooden element with a planar side surface 21. The base body has an elongated and beam-like shape.

[0067] Fig. ib shows a wooden element 1 according to the invention with a coating 3. The coating 3 is arranged on the planar side surface 21 of the base body 2 and is integrally connected thereto.

[0068] Fig. 2 shows an apparatus for producing a wooden element according to the invention. The base body 2 is moved in the direction of the arrow with the side surface 21 to be coated facing upwards on conveyor means 5, 5', 5" past a coating unit 6. The coating unit 6 comprises an application element 61, by which the polymer material is applied as a coating 3 to the side surface 21 of the base body 2. The polymer material is stored in a material supply 8 and is continuously fed to the coating unit 6 via a connecting line 7.

[0069] Also in accordance with the invention is any combination of the embodiments of the wooden element and the method described in the figures and the description. In particular, individual features of the described embodiments can be combined with one another according to the invention. The wooden element according to the invention is not only suitable for construction purposes, but is also suitable for decorative purposes, garden design, or other areas. List of reference symbols

[0070] 1 wooden element

[0071] 2 basic bodies

[0072] 21 Side surface 3 Coating

[0073] 5, 5', 5" funding

[0074] 6 Coating unit

[0075] 61 Order element

[0076] 7 Supply line 8 Material supply

Claims

Patent claims 1. Wooden element (1), in particular a wooden element for use as a structural component, comprising a base body (2) with at least one approximately planar side surface (21) which is at least partially covered with a polymeric coating (3), wherein the polymeric coating (3) forms a material-to-material connection with the wooden element, characterized in that the polymeric coating (3) has a peel strength of at least 3.0 N / 25 mm and a maximum of 15.0 N / 25 mm.

2. Wooden element (1) according to claim 1, characterized in that the polymeric coating is made of a material which has a melting point between 70°C and 300°C.

3. Wooden element (1) according to claim 1 or 2, characterized in that the polymeric coating (3) comprises a thermoplastic polymer material, preferably a thermoplastic biopolymer, and / or that the polymeric coating (3) comprises a wood-polymer composite material and / or that the polymeric coating (3) comprises polyethylene, polypropylene, polyurethane, polyester, polyvinyl chloride, polystyrene, polyamide or ethyl vinyl acetate and / or that the polymeric coating (3) comprises a recycled polymer material.

4. Wooden element (1) according to claim 1, 2 or 3, characterized in that the polymeric coating (3) is an extrusion product and / or that the polymeric coating (3) is the product of a melt casting process and / or a casting process and / or a rolling process.

5. Wooden element (1) according to one of claims 1 to 4, characterized in that the polymer coating (3) comprises several has layers lying one on top of the other and bonded together.

6. Wooden element (i) according to claim 5, characterized in that a corona treatment and / or a plasma treatment has been applied to the polymeric coating (3).

7. Wooden element (1) according to one of claims 1 to 6, characterized in that the polymeric coating (3) is flame-protected and / or flame-retardant and / or flame-resistant and / or that the polymeric coating (3) is UV-resistant.

8. Wooden element (1) according to one of claims 1 to 7, characterized in that the polymer coating (3) covers the wooden element in strips, with uncoated wooden sections lying between the strips.

9. Wooden element (1) according to one of claims 1 to 7, characterized in that the polymeric coating (3) completely covers at least one side surface (21) of the wooden element and in particular has no openings, pores or holes extending through to the wooden element.

10. Wooden element (1) according to one of claims 1 to 9, characterized in that the polymeric coating (3) is optically at least partially transparent.

11. Wooden element (1) according to claim 10, characterized in that an inscription and / or a marking and / or a colored symbol is applied to the wooden element, which is visible through the polymeric coating (3).

12. Wooden element (1) according to one of claims 1 to 11, characterized in that the polymeric coating (3) can be removed from the wooden element at least almost without residue. 13- Wooden element (i) according to one of claims i to 12, characterized in that the wooden element is or comprises a solid wood, a cross-laminated timber, a multi-layer board, a soft fiber board or a hard wood.

14. Wooden element (1) according to one of claims 1 to 13, characterized in that the coating (3) has a structured surface on the side facing away from the wooden element (1) to increase the slip resistance.

15. Wooden element (1) according to one of claims 1 to 14, characterized in that the coating (3) is designed such that knotholes, cracks, gaps and other defects and irregularities in the wooden element are sealed by the coating (3).

16. Wooden element (1) according to one of claims 1 to 15, characterized in that a fleece or a grid is arranged on the side of the coating (3) facing away from the wooden element (1), wherein the fleece or grid is integrally connected to the coating (3) and / or is at least partially embedded in the coating (3).

17. Wooden element (1) according to one of claims 1 to 16, characterized in that the coating (3) is free of residential toxins according to Emicode and / or that the coating (3) comprises less than 5% by weight of volatile substances.

18. Wooden element (1) according to one of claims 1 to 17, characterized in that the coating (3) has an sd value between 0.1 m and 20 m or that the coating (3) is vapor-barrier.

19. Wooden element (1) according to one of claims 1 to 18, characterized in that the wooden element (1) comprises sensors which are arranged on the planar side surface (21) covered by the coating (3) and are encapsulated by the coating (3).

20. Wooden element (1) according to one of claims 1 to 18, characterized in that the coating (3) is arranged directly on the wooden element without intermediate layers.

21. Process for increasing the weather resistance of wooden elements, in particular structural elements made of wood, characterized by the following process steps: - Feeding a wooden element to a coating device; - Aligning a flat surface of the wooden element along a coating direction of the coating device; Feeding a polymer material in solid form to the coating device; - Heating the polymer material; - feeding the heated polymer material in at least partially molten state to at least one application element of the coating device; - Application of the heated polymer material passed through the application element to the flat surface of the wooden element.

22. Method according to claim 21, characterized in that the method additionally comprises the method step Structuring the polymer material applied to the wooden element with a roller, preferably with an embossing roller; comprises.

23. Method according to claim 21 or 22, characterized in that the method additionally comprises the method step Cooling the wooden element coated with the polymer material; includes.

24. A method according to claim 21, 22 or 23, characterized in that the method comprises an extrusion process, a co-extrusion process, a melt casting process, a rolling process or a cast film process.

25. A method according to any one of claims 21 to 24, characterized in that the polymer material is heated to at least 150°C, preferably at least 105°C, more preferably at least 180°C.

26. A method according to any one of claims 21 to 24, characterized in that the polymer material is heated to a temperature which is at least 20°C higher than the glass transition temperature of the polymer material.

27. Use of a wooden element (1) according to one of claims 1 to 14 as a structural or decorative building element.

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