Wood coating manufacturing process and coating according to said process.

Abstract

The invention relates to a method for manufacturing wood cladding comprising, in order, the following steps: a) a log comprising longitudinally extending fibers (15) is supplied; b) said log (10) is peeled to cut wood sheets (18, 20) having transverse fibers (15). The method further comprises the following steps: c) said plurality of wood sheets (18, 20) are superimposed so that the fibers (15) are oriented in the same direction, and the wood sheets (18, 20) are bonded together to obtain a rigid laminated panel (28) having two parallel opposite panel faces (30, 32); and d) said panel (28) is sliced ​​along equidistant planes (P1, P2,… Pn) substantially perpendicular to said two panel faces (30, 32) to obtain wood strips (40), each having two opposite strip faces (42, 44). Figure to be published with the abbreviation: Fig. 3

Description

Title of the invention: Method for manufacturing wood covering and covering according to said method.

[0001] The present invention relates to a method of manufacturing wood covering and to a wood covering obtained according to said method.

[0002] It is known to use tropical woods for the manufacture of exterior works or furniture, because they are capable of resisting bad weather and in particular water.

[0003] For example, a common species, Tectona grandis, or Indochinese teak, is used to make boat decks or garden furniture.

[0004] This material has a high tensile strength and its oil content and tight fibers allow it to resist water penetration well. Furthermore, its color, ranging from pale yellow to bronze or reddish beige with dark veining, gives it a certain aesthetic appearance.

[0005] However, the explosion in its exploitation has led to its scarcity and forced manufacturers to use other materials or to use less of them.

[0006] To be able to use less material, it has been thought, for example, of cutting thin strips of this wood and gluing them onto a laminated support, such as a plywood panel made from a less noble wood species.

[0007] It is well known to produce thin layers of wood continuously from logs. To do this, the two ends of the log are engaged in two opposite claws so as to be able to rotate it substantially around its axis of symmetry. A cutting blade is then adjusted tangentially and parallel to this axis of symmetry, then it is continuously driven towards the center of the log, while the log is driven in rotation, to be able to cut sheets of a thin thickness.

[0008] After drying these sheets of wood, strips are then cut to be glued onto the laminated support. In this way, a covering is obtained which has the aesthetic aspects of teak, for example, without consuming large quantities of this noble wood.

[0009] However, a problem which arises and which the present invention aims to solve is to provide a method making it possible to overcome the hazards linked to the availability and supply of this noble wood for manufacturing aesthetic wood coverings.

[0010] For this purpose, there is proposed, according to a first object, a method for manufacturing wood covering comprising, in order, the following steps: a) a wooden ball extending along a longitudinal axis is provided, said wooden ball comprising fibers extending along said longitudinal axis; b) unrolling said log of wood to tangentially cut sheets of wood, each of said sheets of wood having fibers extending in the same direction.

[0011] The method according to the invention further comprising the following steps: c) superimposing said plurality of wood sheets so that the fibers of the wood sheets are oriented in the same direction, and bonding together the wood sheets of said plurality of superimposed wood sheets to obtain a rigid laminated panel having two parallel opposite panel faces; and, d) slicing said panel along equidistant slicing planes substantially parallel to said same direction and substantially perpendicular to said two panel faces to obtain wood strips each having two opposite blade faces defined by said slicing planes and two opposite edges defined by said two opposite panel faces.

[0012] Thus, a characteristic of the invention lies in the implementation of thin wood sheets, glued and superimposed to obtain a laminated panel and then in the slicing of this panel according to equidistant planes parallel to the orientation of the fibers and perpendicular to the two opposite faces of the panel so as to obtain wooden strips having specific opposite faces. Indeed, the opposite faces of the wooden strips thus obtained have lines corresponding to the thicknesses of the wood sheets, and give it an aesthetic appearance comparable to that of teak.

[0013] Preferably, the wooden slats are exposed to UV radiation in order to give them a color even closer to that of teak.

[0014] Furthermore, thanks to the process according to the invention, wooden strips are obtained that are free of internal mechanical stresses. Indeed, the process of cutting the wooden logs allows the radial mechanical stresses, which arise naturally during the growth of the tree from which they come, to be relaxed. And in addition, the production of laminated panels, where the fibers of the wooden sheets are oriented in the same direction, in other words, "thread on thread", allows residual mechanical stresses to be relaxed. In other words, the wooden strips have a dimensional stability over time that they would not have if they were obtained directly after sawing and splitting wooden logs.

[0015] Such wooden blades can then be glued, after slicing, for example onto a layer of composite materials or a “gelcoat”.

[0016] According to another embodiment of the invention, which is particularly advantageous, according to a step e), a support panel is provided, and said wooden strips are applied flat to said support panel. The support panel is for example made of a laminated panel with a thickness of around 1.5 mm.

[0017] The laminated panel can be made, for example, from poplar or maritime pine species. The nature of the laminated support is in no way limiting.

[0018] Preferably, said wooden slats are applied parallel to each other.

[0019] Also, said wooden slats are advantageously glued to the support panel. They are for example glued using a polyurethane or epoxy resin, which gives them strong adhesion.

[0020] According to a particularly advantageous embodiment, the wooden slats are spaced apart from each other by a given distance and preferably, a seal is applied between the wooden slats. For example, a silicone-type sealant, which is waterproof and elastic, is inserted between the wooden slats.

[0021] Also, and according to a preferred embodiment, in step c), said wooden sheets are bonded together with an adhesive based on melamine and urea-formaldehyde. Advantageously, resorcinol is added to the adhesive mixture in order to densify the adhesive network. This gives the laminated panel, usually called "plywood", great rigidity.

[0022] Furthermore, said plurality of superimposed wooden sheets are preferably heated to a temperature above 100°C to bond said wooden sheets together. For example, such a temperature is applied for 30 minutes in order to obtain optimal crosslinking of the adhesive composition. Consequently, better rigidity of the laminated panel is obtained.

[0023] The heating time is obviously adapted according to the thickness of the desired panel and also the polymerization speed of the adhesive.

[0024] Furthermore, in step b), sheets of wood with a thickness of between 1 mm and 4 mm are cut. The sheets of wood thus cut during unrolling have an average thickness of 1.5 mm for example.

[0025] Also, preferably, prior to step c), the wood sheets are sorted according to their color so as to be able to obtain a uniform color of the veneers.

[0026] Preferably, in step d), said panel is cut to obtain wooden slats having a thickness of between 5 mm and 10 mm. For example, the wooden slats have a thickness of 7 mm. In this way, the wooden slats remain perfectly stable over time, both dimensionally and aesthetically.

[0027] According to a particularly advantageous embodiment of the invention, in step a), a Milicia excelsa log is provided. The most commonly used vernacular name for this exotic wood is Iroko. It has the advantage of being abundant. The method according to invention is in no way limited to this particular type of wood.

[0028] Furthermore, and according to a second object, the invention relates to a wood covering obtained in accordance with the method described above.

[0029] Other features and advantages of the invention will become apparent upon reading the description given below of a particular embodiment of the invention, given for informational purposes but not as a limitation, with reference to the appended drawings in which:

[0030] [Fig. 1] is a schematic perspective view illustrating a first stage of the method according to the invention;

[0031] [Fig.2] is a schematic perspective view illustrating a second stage of the method according to the invention;

[0032] [Fig.3] is a schematic perspective view illustrating a third stage of the method according to the invention;

[0033] [Fig.4] is a schematic perspective view illustrating a fourth stage of the method according to the invention;

[0034] [Fig.5] is a schematic perspective view illustrating an optional step of the method according to the invention; and,

[0035] [Fig.6] is a flowchart of the steps of the method according to the invention.

[0036] [Fig.l] shows a wooden ball made of Iroko 10 rotated along its axis of S symmetry in the R direction. Iroko is an abundant tree species, significantly less stable than teak. On the other hand, thanks to the process according to the invention, a stable final product is obtained, as will be explained below.

[0037] The wooden log 10 comes from a portion of a tree trunk from which the branches have been removed. Also, the tree is made up of a plant tissue composed of bundles of longitudinal cells extending in a mean direction parallel to the axis of the trunk and therefore to the axis of symmetry S. These longitudinal cells form the wood fibers 15 shown schematically on the wooden log 10.

[0038] A first step 17 of the method according to the invention, illustrated in [Fig.6], is thus the supply of the wooden ball 10.

[0039] Also, [Fig.l] shows a cutting blade 12 whose edge 14, shown in broken lines, bears tangentially on the wooden log 10.

[0040] In this way, the combined movements of the translation of the cutting blade 12 towards the axis of symmetry and the rotation of the ball 10, cause the cutting of a thin layer of wood 16, with an average thickness of 1.5 mm.

[0041] This thin layer of cut wood 16 thus makes it possible to form sheets of wood, which are driven in movement in the direction of arrow V opposite the wooden ball 10 and of which only two 18, 20 are shown in [Fig.l].

[0042] On these sheets of wood 18, 20 we find the schematic representation of the wood fibers 15, which extend transversely relative to the direction of advancement of the thin layer of wood 16 during the peeling operation.

[0043] The cutting of the wooden sheets 18, 20 constitutes a second step 22 of the method according to the invention.

[0044] Also, according to an intermediate step, the wooden sheets 18, 20 are advantageously dried in a suitable oven.

[0045] Refer to [Fig. 2] where the wooden sheets 18, 20 are found plumb with each other and where the wood fibers 15 are oriented in the same direction. It will be observed that the wooden sheets 18, 20 will be stacked in the same way as a plurality of substantially identical wooden sheets 24. And all the wooden sheets are applied to each other, so that their fibers 15 are oriented in the same direction. In other words, the wooden sheets, or plies, are applied to each other "thread on thread".

[0046] The panel is composed of an odd number of plies, according to the method for composing a plywood panel. Also, prior to their contact, the even sheets of wood were glued on each of their faces, with a mixture of urea-formaldehyde-resorcinol resin. The plurality of sheets of wood 24 is then hot pressed and maintained thus for a period of between 20 minutes and 40 minutes. The time is in line with the desired thickness of the panel and the time necessary for the polymerization of the adhesive.

[0047] The temperature of the press is for example greater than 100°C.

[0048] In this way, not only are the plurality of wooden sheets compressed against each other, and therefore the air which extends between the sheets is expelled, but in addition, the reaction of the resin mixture which then hardens around the wood fibers of the plurality of sheets 24 is increased.

[0049] At the end of this assembly step 26, a rigid laminated panel 28 is obtained, as illustrated in [Fig. 3], having two opposite panel faces 30, 32 and two opposite edges 34, 36.

[0050] A sufficiently large number of wooden sheets are thus applied one on top of the other so that at the end of the assembly step 26, a laminated panel of a given thickness of, for example, between 20 mm and 70 mm is obtained. Advantageously, a number of wooden sheets is chosen so that the thickness E of the laminated panel is substantially equal to 36.5 mm.

[0051] Next, a slicing step 38 of the rigid laminated panel 28 is carried out according to equidistant slicing planes PI, P2, ... Pn, parallel to the average direction of the fibers of the pressed wood sheets and perpendicular to the two opposite faces 30, 32.

[0052] The rigid laminated panel 28 is thus cut parallel to its opposite edges 34, 36, the cutting planes being spaced apart from each other by the same value between for example between 5 mm and 10 mm. Advantageously, the cutting planes PI, P2, ... Pn, are spaced from each other by 7 mm.

[0053] In this way, identical wooden strips are obtained, one example 40 of which is illustrated in [Fig. 4]. The wooden strip 40 thus has a width E of 36.5 mm corresponding to the thickness of the laminated panel 28 and a thickness e of 7 mm.

[0054] Thus, such a blade 40 has two opposite blade faces 42, 44 having substantially the same pattern, and two opposite edges 43, 45 defined by the two panel faces 30, 32.

[0055] On the blade faces 42, 44, there appear lines 46, 48, 50 regularly spaced, and corresponding to the thicknesses of the sheets of wood. In addition, the wood fibers 15 extend substantially parallel to these lines 46, 48, 50.

[0056] The lines give the wooden slats an aesthetic character. In addition, according to an optional, particularly advantageous step, the slats 40 are exposed to UV radiation in order to modify their color. Such exposure makes it possible to obtain slats having a color close to that of teak.

[0057] In addition, given its manufacturing process, the wooden blades retain good dimensional stability. Indeed, the internal mechanical stresses generated naturally in raw wood are largely relaxed during the implementation of the process according to the invention.

[0058] According to a first embodiment of the invention, the wooden slats 40 obtained in accordance with the method according to the invention are glued parallel to each other, on a laminated support 52 as shown in [Fig. 5]. The wooden slats 40 are for example spaced from each other by a distance of approximately 5 mm. And in this space, a silicone-type mastic is for example injected so as to form a watertight seal 54.

[0059] The laminated support 52 thus plated can then be used in a particularly aggressive external environment, for example on the deck of a boat.

[0060] According to a second embodiment of the invention, the wooden strips 40 are applied directly to the surface to be covered, previously coated with a gelcoat. The wooden strips 40 can then be adjusted edge to edge. Indeed, their dimensional stability is such that there is no risk of deformation of the surface.

Claims

Claims

1. A method of manufacturing wood cladding comprising, in order, the following steps: a) providing a wood log (10) extending along a longitudinal axis, said wood log comprising fibers (15) extending along said longitudinal axis; b) unwinding said wood log (10) to tangentially cut wood sheets (18, 20), each of said wood sheets having fibers (15) extending in the same transverse direction; characterized in that it further comprises the following steps: - c) superimposing said plurality of wood sheets (18, 20) so that the fibers (15) of the wood sheets are oriented in the same direction, and bonding together the wood sheets (18, 20) of said plurality of superimposed wood sheets to obtain a rigid laminated panel (28) having two parallel opposite panel faces (30, 32);and, - d) said panel (28) is cut along equidistant cutting planes (PI, P2,... Pn) substantially parallel to said same direction and substantially perpendicular to said two panel faces (30, 32) to obtain wooden blades (40) each having two opposite blade faces (42, 44) defined by said cutting planes (PI, P2,... Pn) and two opposite edges (43, 45) defined by said two opposite panel faces.;

2. Method according to claim 1, characterized in that furthermore according to a step e), a support panel (52) is provided, and in that said wooden strips (40) are applied flat on said support panel (52).

3. Method according to claim 2, characterized in that said wooden blades (40) are applied parallel to each other.

4. Method according to claim 2 or 3, characterized in that said wooden strips (40) are glued to said support panel (52).

5. Method according to claim 3 or 4, characterized in that a joint (54) is applied between said wooden slats.

6. Method according to any one of claims 1 to 5, characterized in that in step c), said wooden sheets (18, 20) are bonded together with an adhesive based on melamine and urea-formaldehyde.

7. Method according to claim 6, characterized in that said plurality of superimposed wooden sheets (18, 20) are brought to a temperature su- above 100°C to bind the said sheets of wood together.

8. Method according to any one of claims 1 to 7, characterized in that in step b), sheets of wood (18, 20) with a thickness of between 1 mm and 4 mm are cut.

9. Method according to any one of claims 1 to 8, characterized in that in step d), said panel (28) is cut to be able to obtain wooden strips (40) having a thickness of between 5 mm and 10 mm.

10. Method according to any one of claims 1 to 9, characterized in that in step a), a ball of Milicia excelsa is provided.

11. Wood coating of wood obtained in accordance with the method according to any one of claims 1 to 10.

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