Method of forming three-dimensional structure on wood fibres having flat surface

Abstract

The invention relates to a method for forming a three-dimensional structure on wood fibres having a flat surface. Specifically, the invention relates to a method for forming a three-dimensional structure on wood fibres having a flat surface, comprising the following steps, but not necessarily in the preferred order of: a) providing a wood surface; b) subjecting the wood surface to compression by applying a variable pressure in a plurality of regions, resulting in different topographic compaction of wood fibres; c) coupling the wood surface obtained in step b) with a support element; and d) smoothing and calibrating the surface of the supporting wood obtained according to the step c) so as to restore the flatness of the surface and form a design with a three-dimensional perspective effect.

Description

Technical Field

[0001] The present invention relates to a method for forming a three-dimensional structure on wood fibers having a flat surface. Background Art

[0002] The production of boards or coverings for furniture, trim or walls (wainscoting) with an original and aesthetic appearance, wooden coverings for cars is a source of constant research for companies specializing in the carpentry industry.

[0003] In particular, a problem is felt to be the ability to give a three-dimensional appearance or perspective effect to a flat surface, such as veneer for covering wood.

[0004] By three-dimensional appearance or perspective effect we mean, for example, the typical irregular appearance defined by knots and fibers that are evident in three-dimensional perspective, which fine wood panels will have after being properly processed and sanded. Alternatively, the three-dimensional effect of a flat surface can be created by various irregular or geometrical designs, which are not however created by ink printing or similar methods. Summary of the invention

[0005] The above objects have been achieved by a method for forming a three-dimensional structure on wood fibers having a flat surface as defined in the appended claims, which for the purpose of a thorough description form an integral part of the present disclosure.

[0006] Therefore, an object of the present invention is to provide a method for forming a three-dimensional structure on wood fibers having a flat surface, comprising the following steps:

[0007] a) provide a wood surface;

[0008] b) subjecting the wood surface to compression by applying variable pressure in a plurality of zones, thereby producing different topographical compactions of the wood fibers;

[0009] c) coupling the wood surface obtained in step b) to a supporting element;

[0010] d) grinding and calibrating the supported wood surface obtained according to step c) to restore the flatness of the surface and form a design with a three-dimensional perspective effect.

[0011] Another object of the invention is a material obtainable by the method according to the invention, comprising a flat wood surface on which a picture with a three-dimensional perspective effect is formed.

[0012] Further features and advantages of the invention will emerge from the following description of an embodiment given for illustrative and non-limiting purposes. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1A and Figure 1B The wood board is shown before and after being subjected to the method of the invention. DETAILED DESCRIPTION

[0014] According to a first embodiment, the method for forming a three-dimensional structure on a wood fiber having a flat surface according to the present invention comprises the following steps in sequence:

[0015] a) provide a wood surface;

[0016] b) subjecting the wood surface to compression by applying variable pressure in a plurality of zones, thereby producing different topographical compactions of the wood fibers;

[0017] c) connecting the wood surface obtained in step b) to a supporting element;

[0018] d) Smoothing and aligning the supported wood surface obtained according to step c) to restore the flatness of the surface and form a design with a three-dimensional perspective effect.

[0019] In certain embodiments, steps b) and c) may be performed in reverse order.

[0020] The wood surface of step a) is, for example, a sheet or veneer of a wood species such as commercially named oak, ayous, maple, chestnut, walnut, pine, fir, eucalyptus, mahogany, erable, tanganika, tay, ash, bolivar, taba, fromajer, etc.

[0021] For the purposes of the present invention, the pressing step b) is a manufacturing process involving the use of heat and pressure to impart a three-dimensional pattern (embossing) onto the wood surface.

[0022] The extrusion step b) is carried out by applying a predetermined pressure and temperature to the wood surface. For the purpose of the present invention, it can be advantageously carried out at a temperature of 90°C to 170°C, preferably 110°C to 160°C, more preferably 120°C to 150°C and a pressure of 10 to 100 Kg / cm 2 , preferably 20 to 80 Kg / cm 2 , more preferably 30 to 70 Kg / cm 2 , even more preferably 40 to 60 Kg / cm 2 Operate under pressure.

[0023] The time for which step b) is performed is usually greater than 1 second, and this may depend on the shape and the nature of the wood being processed, and may preferably vary between 1 and 60 seconds, more preferably between 10 and 30 seconds. It must be understood that there is no specific upper limit to the application time, although in the case of a calender, even a minimum time of 1 second may be applied. In fact, the length of time depends entirely on the cost-effectiveness of the process.

[0024] In step b), customary apparatuses may be used, such as a hydraulic press (discontinuous process) or a calender (continuous process).

[0025] Depending on whether a hydraulic press or a calender is used, these devices will be equipped with forming plates or machined rollers, respectively, in order to apply said variable pressure in multiple areas on the wood surface.

[0026] The forming plate is made of a sheet, usually made of metal (iron, aluminium, alloys like steel etc.), fixed to the piston by a coupling system to follow the movement of the piston. Similarly, the calender roll will have a surface with an embossed or negative design.

[0027] The plates or rollers are specially shaped with a unique design for printing each individual graphic. Variable compression of the fibers is created by the variable height of the peaks of the design engraved in high relief and negative on the plate. With the same pressure generated by a hydraulic press or calender roller, the higher the peaks, the more the wood fibers are compacted.

[0028] It is also possible to obtain a variable extrusion by processing several overlapping wood sheets (for example three), obtaining a greater or lesser extrusion if these sheets are in contact or not with the board. In particular, a greater mark is observed in the sheet that is directly in contact with the board, while a smaller mark is observed in the layer furthest away. In this way, sheets with different three-dimensional effects can be obtained in one step, which can even be used independently on different types of products.

[0029] The extrusion process can be carried out in a single stage or in several separate or consecutive stages, involving subsequent reworking or different treatments using the same plates / rollers on the same and opposite surfaces of the sheet.

[0030] As mentioned before, temperature affects the process: higher temperatures tend to reduce the mechanical resistance of the wood, thus facilitating the squeezing / marking phase.

[0031] Furthermore, the greater the pressure, the more the wood fibers are squeezed. When the material breaks, i.e. when the resistance limit of the fibers is reached, the pressure limit is reached, which will depend on the type of design, the wood species and the thickness of the wood surface subjected to step a). The maximum pressure can be determined from time to time by experimental tests.

[0032] The joining step c) involves gluing or laminating the extruded wood surface according to step b) to a second material acting as a supporting element. This joining process can improve or enhance the inherent properties of the material, for example by increasing its rigidity, thickness, etc., or provide it with new properties, such as flexibility, mechanical resistance, etc.

[0033] The support element is selected from different types of materials, such as plant or synthetic organic matrices, such as paper, nonwoven fabrics of various basis weights, wood (e.g. multilayer board, MDF, particle board or other boards of various thicknesses), etc., or inorganic matrices, such as metal (aluminum foil, fiberglass, etc.). The support element will generally be selected according to the type of intended application of the final material.

[0034] More preferably, the support element has a basis weight of about 90 g / m 2 Cellulose-based nonwoven fabric (80% plant fiber).

[0035] For the joining step c), different types of glues may be used, both liquid and solid, such as vinyl-based, acrylic-based, phenol-based, polyurethane-based or similar glues.

[0036] Similar to the previous step b), the joining step c) can be carried out in a hydraulic press or calender, either hot or cold, depending on the type of support element and adhesive used. The technical conditions of this step directly depend on the nature of the raw materials used, and the pressure ranges from 4 to 100 Kg / cm 2 , the temperature is 70°C to 160°C, and the treatment time is 30 to 120 seconds. In a preferred embodiment, the connection is at a temperature of 100°C to 150°C, more preferably 125°C to 140°C and 6 to 60 Kg / cm 2 , more preferably 7.5 to 40 Kg / cm 2 under pressure.

[0037] The grinding step d) comprises grinding and calibrating the supported wood surface obtained in step c).

[0038] The calibration process is the process of removing material in order to reduce the thickness of the entire surface in a uniform manner. The sanding process is a process that can be used to flatten a surface that has become irregular due to previous processes, to polish the surface and prepare it for any subsequent processing. These processes can also take place simultaneously. The sandpaper used affects the aesthetic and technical properties of the product and can be used with a grit between 60 and 400.

[0039] The wood surface previously compacted and connected to the support element is passed into the calibrator / sanding machine. In this way the material is simultaneously calibrated back to a standard thickness between 0.1 mm and 2 mm, preferably between 0.3 mm and 1 mm, more preferably about 0.5 mm, and at the same time is polished to restore the wood surface, which presents areas of compression of different entities in the initial flatness.

[0040] The sander / calibrator is of the traditional type. A steel frame supports one or more pairs of rollers on which sandpaper belts of different grits slide. In one machine there can be a different number of roller pairs, even up to six. The surface to be sanded / calibrated passes under the rollers on a motorized belt that allows it to slide. The height of the surface with the cover is adjustable, allowing one to adjust the thickness of the material whose surface needs to be sanded / calibrated. The machine is supported by a suction system to avoid dust accumulation.

[0041] At the end of step d), a material is obtained comprising a flat wood surface on which a drawing with a three-dimensional perspective effect is formed, which constitutes another object of the invention.

[0042] Figure 1A and Figure 1B The planks are shown before and after the processing object of the invention. Although the flatness of the processed surface is preserved, the three-dimensional effect obtained is obvious.

[0043] Figure 1B The three-dimensional image shown is schematic only and is one of an infinite number of images that can be imparted to the wood surface, depending on the shape and degree of topographic compaction imparted to the surface.

[0044] The material thus obtained can be used in the same way as ordinary wood veneers, for example for the production of veneers or for parts of furniture or other decorative elements.

[0045] Obviously, what has been described is only one specific embodiment of the invention. A person skilled in the art will be able to make all necessary modifications to the method of the invention to adapt it to specific conditions and forms of application without departing from the scope of protection defined in the appended claims.

Claims

1. A method for forming a three-dimensional structure on a wood fiber having a flat surface, comprising the following steps in sequence: a) provide a wood surface; b) compressing the wood surface by applying varying pressures to a plurality of regions, thereby producing different topographical compactions of the wood fibers; c) coupling the wood surface obtained in step b) to a supporting element; d) Smoothing and calibrating the surface of the supported wooden board obtained according to step c) to restore the flatness of the surface and form a three-dimensional perspective effect.

2. The method according to claim 1, wherein: The wood surface of step a) is selected from sheets or veneers of wood species such as oak, ayous, maple, chestnut, walnut, pine, fir, eucalyptus, mahogany, eucalyptus, tanganyika, tamarind, white oak, bolivar, taba, flago, etc.

3. The method according to claim 1 or 2, wherein: The extrusion step b) is performed by applying a predetermined pressure and temperature to the wood surface, wherein the temperature is between 90°C and 170°C, preferably between 110°C and 160°C, more preferably between 120°C and 150°C, and the pressure is between 10 and 100 Kg / cm 2 Between, preferably 20 to 80Kg / cm 2 More preferably, 30 to 70 Kg / cm 2 Between, even more preferably 40 to 60 Kg / cm 2 between.

4. The method according to any one of claims 1 to 3, wherein: Step b) is carried out for a time longer than 1 second, preferably 10 to 30 seconds.

5. The method according to any one of claims 1 to 4, wherein: Step b) is carried out by means of a hydraulic press or a calender, wherein the hydraulic press or the calender is provided with a forming plate or a machined surface, respectively, wherein the different compression of the fibers of the wood surface is produced by the different heights of the ridges of the high relief and negative engraving on the surface of the plate or the roller.

6. The method according to any one of claims 1 to 5, wherein: The extrusion step b) can be carried out in a plurality of separate or consecutive steps, which steps consist in cooling the semi-finished part and then reworking it with the same or different plates or rollers.

7. The method according to any one of claims 1 to 6, wherein: The joining step c) consists in gluing or rolling the pressed wood surface according to step b) onto a second material acting as a supporting element.

8. The method according to claim 7, wherein: The bonding is achieved by liquid or solid glue, preferably vinyl-based, acrylic-based, phenol-based, polyurethane-based glue or the like.

9. The method according to any one of claims 1 to 8, wherein: The support element is selected from materials of an organic base, synthetic or plant, such as paper, nonwovens of various basis weights, wood, or materials of an inorganic base, such as metals, for example aluminum foil or fiberglass.

10. The method according to claim 9, wherein: The support element contains 80% plant fibers and has a basis weight of about 90 g / m 2 Cellulose-based nonwoven fabric.

11. The method according to any one of claims 1 to 10, wherein: Step c) is carried out by applying 4 to 100 Kg / cm 2 Between, preferably 6 to 60Kg / cm 2 Between, more preferably 7.5 to 40Kg / cm 2 and a temperature between 70°C and 160°C, preferably between 100°C and 150°C, more preferably between 125°C and 140°C, and a processing time between 30 and 120 seconds.

12. The method according to any one of claims 1 to 11, wherein: Step d) is performed by a polisher / calibrator using sandpaper with a grit range between 60 and 400.

13. The method according to any one of claims 1 to 12, wherein: The wood surface is calibrated to return the wood surface to a standard thickness between 0.1 mm and 2 mm, or between 0.3 mm and 1 mm, or about 0.5 mm, and is smoothed to restore the wood surface with pressed areas of different sizes to the original flatness.

14. The method according to any one of claims 1 to 13, wherein: Steps b) and c) are carried out in reverse order.

15. A material obtainable by a method according to any one of claims 1 to 14, comprising a flat wood surface on which a three-dimensional perspective image is formed.

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