EP0309356A1 - Method of manufacturing a wooden article with integrated colouring - Google Patents

Abstract

A method of manufacturing a material (14) consisting of a plurality of adjacent wooden slats (2'a, 2'b, ...), mutually separated over their entire height and over their entire length by a joint of coloured adhesive (3) securing the slats together. This method comprises the following operations: - superposition of a plurality of wooden panels (2a, 2b, ...) after having spread a layer of coloured adhesive over at least one face of each panel, - pressing of the stack thus obtained, - cutting-out of this stack, in slices (A-B) whose width corresponds to the height of the slats, and is characterised in that each of the panels of the stack is provided with means (5) making it possible to obtain a thickness of the joint (3) between adjacent slats of the material (14) which has a predetermined value and which is uniform over the entire length of the slats. Applications to the wood construction industry in general and, in particular, with a view to the manufacture of facing articles and to the decoration of flat or curved surfaces. <IMAGE>

Description

The present invention relates to a method for manufacturing a wooden material of the integrated coloring type, as well as to the material thus obtained.

A wood material with integrated coloring consists of a plurality of adjacent wooden strips and separated from each other over their entire height and over their entire length by a colored substance, of synthetic or natural material, acting as an adhesive and securing the strips mentioned above.

A material of this type has been known in the art for a long time, as shown in US Patent 2,062,590.

However, until now, we have been unable to control the uniformity of the thickness of the colored glue joint between lamellae, so that the thickness of the colored joint corresponds to the thin film of glue which remains after tightening under pressure. plates bonded together and from which the above material is obtained.

The aim of the present invention is therefore to provide a method for manufacturing a wooden material of the aforementioned type, which better meets the requirements of the technique than materials of the same type, aiming at the same aim, previously known, in particular in that:
the thickness of the adhesive joint is liable to vary within a relatively wide range of values, while remaining uniform over the entire length of the strips which it fixes together,
- the production cost is very greatly reduced due to the possibility of controlling the quantity of glue to be used,
the means used to carry out the invention make it possible to make the wooden material also capable of exercising a sound and / or thermal insulation function,
- the material can be adapted to surfaces curved and absorb the expansions and retractions of the wood, of which it is composed, which are due to hygrometric and thermal variations, and this without deforming and therefore without affecting the desired decorative effect.

The present invention relates to a method of manufacturing a material consisting of a plurality of adjacent wooden strips separated from each other over their entire height and over their entire length by a colored glue joint securing the strips together, which method includes the following operations:
- superimposition of a plurality of wooden plates after having spread a layer of colored glue on at least one face of each plate,
- pressing of the stack thus obtained,
- cutting of this stack, preferably perpendicular to the plane defined by it, in slices whose width corresponds to the height of the lamellae, so as to obtain the aforementioned material,
and is characterized in that each of the plates of the aforementioned stack is provided, on at least one face thereof, with means making it possible to obtain a thickness of colored adhesive between superposed plates of the above-mentioned stack, and therefore a thickness of the joint between adjacent lamellae of the aforementioned material, which has a predetermined value varying within an appropriate range, and which is uniform over the entire length of the plates, and therefore of the lamellae.

According to a first preferred embodiment of the method according to the invention, the aforementioned means consist of at least a plurality of longitudinal ribs spaced apart, the height of which depends on the aesthetic effect and / or the economy of glue sought, namely the thickness of the colored glue joint between adjacent lamellae, each layer of colored glue being spread over the aforementioned ribs and in the grooves separating two adjacent ribs.

According to a preferred arrangement of this first embodiment, in the grooves separating two adjacent ribs are provided deeper recesses communicating with the corresponding grooves and intended to be filled with an adhesive material also having sound insulation properties and / or thermal.

According to a preferred embodiment of this first embodiment and of this arrangement, each slicing is carried out so as to remove the ribs and to essentially include a groove or groove separating two adjacent ribs, the ribs being relatively narrow compared to the grooves or grooves between them. More precisely, when the ribs are removed during cutting, they have a width which is necessarily less than the width of the cutting element of the cutting tool used (in particular constituted by a circular saw).

According to another advantageous arrangement of this first embodiment, each plate comprises first and second plurality of ribs of different widths, each rib of the first plurality being separated on either side by two grooves having the same depth or different depths and jointly separating each rib of said first plurality of two ribs of said second plurality.

According to an advantageous modality of this arrangement, each slicing is carried out so as to essentially include a rib, belonging to one of said first or second pluralities and before the widest width, as well as the grooves which delimit it, while removing the narrower ribs.

According to yet another advantageous arrangement of this first embodiment, each plate has a single plurality of ribs separated by grooves.

According to an advantageous modality of this arrangement, each slicing is carried out so as to essentially include a rib and a groove.

According to the invention, the aforementioned ribs are continuous or discontinuous over the entire length of the plates.

Also according to the invention, said ribs can be made in one piece with the plate which carries them or attached to it.

Still also in accordance with the invention, the cutting into longitudinal slices of the stack of superimposed plates glued together is carried out so that each slice comprises, at least in part, said means having served to define the thickness of colored glue and ensuring its uniformity over the entire length, in particular for reasons of economy of colored glue and / or desired aesthetic effect. The cutting can also be carried out so as to exclude these means.

In addition to the foregoing provisions, the invention also comprises other provisions, which will emerge from the description which follows.

The invention will be better understood with the aid of the additional description which follows, which refers to the appended drawings in which:
- Figure 1 shows a stack of superimposed plates each comprising a first type of means according to the invention;
- Figure 2 shows a material obtained by slicing the stack illustrated in Figure 1;
- Figures 3, 5 and 7 illustrate variants with respect to the stack illustrated in Figure 1;
- Figures 4, 6 and 8 illustrate the materials obtained by slicing the stacks of Figures 3, 5, and 7, respectively;
- Figure 9 illustrates another configuration possible for one of the plates of a stack;
- Figure 10 illustrates a plurality of elements of the type shown in Figure 2, juxtaposed between them and applied on a suitable support.

It should be understood, however, that these drawings, and the corresponding descriptive parts, are given solely by way of illustration of the subject of the invention, of which they in no way constitute a limitation.

Figure 1 illustrates a stack 1 of wooden plates 2a, 2b, ... superimposed one on the other and joined together by a colored substance 3 acting as glue (for example, an epoxy glue colored in its mass by aqueous pigment pastes).

Each of the wooden plates is machined so as to have ribs 5 (equidistant in the case of FIG. 1); it is easy to verify that these ribs, of uniform height, constitute an effective means so that the thickness of the layer of colored glue 3 has a desired value (when this is applied in the spaces 4 separating two adjacent ribs 5 and on these same ribs), in principle variable over a relatively wide range which can exceed 3 mm and even more, while ensuring the uniformity of this thickness over the entire length of the plates.

The wooden material obtained from the stack 1 of Figure 1 by cutting slices AB, namely between the planes A and B, defined by the axes xx ′ and yy ′, is illustrated in Figure 2 by the reference 14. These axes correspond to the axes of the cutting element of the cutting tool, the width of which is greater than that of the ribs 5, which are therefore removed during cutting, so as to reveal, on both sides other of the cutting lines, the colored substance 3 on the two main faces of the element 14. The latter is formed of a plurality of strips 2′a, 2′b, ... (5 in the case shown in FIG. 2) which are joined together by joints 3 of colored glue, the thickness of which has the desired value, which is equal at the height 3a of the ribs 5 increased by the small thickness 3b of glue applied to these ribs and remaining after compression of the stack (aimed at joining, by gluing, the superimposed plates) and which is substantially uniform over the entire length of the 'Element 14. The cutting thereof is done in the direction of the line, by any suitable means, for example with a circular saw or band saw.

FIG. 3 illustrates an alternative embodiment of the method according to the invention. In this case, the means intended to give the thickness of glue between adjacent lamellae the desired value and to make it uniform over their entire length are constituted by a plurality of ribs 8 of uniform height, obtained by machining on one of the sides of the plates. 6a, 6b, ... which makes up the stack 10. A layer of colored glue is applied between two superimposed plates so as to fill the grooves 7 separating two consecutive ribs and to be applied to these ribs (or flats) 8 .

Cutting the stack 10 by slices along planes A and B, defined by the axes xx ′ and yy ′, makes it possible to obtain the element 15 illustrated in FIG. 4 constituted by adjacent strips 6′a, 6 ′ b separated by joints 9 of colored glue, the thickness of which is different on the two main faces of the element 15, while being uniform on each of these faces.

On the upper face of the element 15, the thickness of the seal 9 is equal to the depth 9a of the grooves 7 increased by the small thickness 9b of adhesive which is applied to the spaces (ribs) separating two adjacent grooves and which remains after compression of the stack 10, while on the underside the thickness of the joint is constituted by this aforementioned low value 9b. Of course, in this case, only the upper face is intended to be exposed.

It is also easy to verify that the mode of implementation of the method corresponding to FIG. 3 corresponds to the most economical solution as regards the quantity of colored glue to be used.

Another example of implementation of the method according to the invention is illustrated in FIG. 5. Here, the aforementioned means, aimed at obtaining joints of colored glue between adjacent lamellae which have a given uniform thickness over their entire length, are formed by a first plurality of ribs 12 and a second plurality of ribs (or flats) 13, the ribs of the first plurality being arranged alternately with the ribs of the second plurality and having a width less than that of the latter. The layer of colored glue applied between two superimposed plates 11a, 11b, ... therefore fills the two pluralities of grooves 17 and 18, of different depths, separating two adjacent ribs 12, 13 of different widths and is applied to these ribs. The cutting of the stack 20 illustrated in FIG. 5 along the planes AB, defined by the axes xx ′ and yy ′, makes it possible to obtain the element 16 constituted by strips 11′a, 11′b, ... and seals 19 of colored glue having a different thickness on the two main faces of the element 16, while being uniform on each of these faces.

On the upper and lower faces of the element 16, the thickness of the seal 19 is equal to the depth 19a and 19c of the grooves 18 and 17, respectively, increased by the small thickness 19b of glue which is applied to the ribs 12 and 13, separated by the grooves 17 and 18, and which remains after compression of the stack 20. Between the two portions 19a and 19c of the seal 19, the latter has a thickness having the aforementioned low value 19b.

The solution illustrated in Figure 6 allows to expose one or the other of the main faces of this element, depending on the desired aesthetic effect.

The thickness of the adhesive joint which appears on the upper face of the element 15 of FIG. 4 and on the upper and lower faces of the element 16 of FIG. 6 varies within a relatively wide value range which can exceed 50 mm and even more.

Yet another example of implementation of the method according to the invention is illustrated in FIG. 7 where, on each plate, a plurality of ribs 22 is formed, separated by a plurality of grooves 25 with composite profile, in particular in the form of an inverted Ω , which are filled with an adhesive substance 27 also having insulating properties from the acoustic and / or thermal point of view, in particular constituted by flexible polyurethane.

The grooves with composite profile 25 have a deeper portion 25a delimited on either side by two shallower portions 25c.

Of course, during the application of the colored glue on each face of the plates 21a, 21b, ... of the corresponding stack 30 of FIG. 7, this fills the grooves 25. A film of glue is applied also on the ribs 22 separating these grooves, so that, by cutting the stack 30 along the planes A, B, defined by the axes xx ′ and yy ′, the element 23 illustrated in FIG. 8 is obtained, consisting lamellae 21′a, 21′b separated by seals 24 having the desired thickness 24c on the two main faces of the element 23 (equal to the depth of the grooves 25c, at a shallower depth, of the grooves 25 with increased composite profile of the small thickness 24b of adhesive which is applied to the spaces 22 separating the grooves 25 and which remains after compression of the stack 30). This thickness is chosen according to the desired aesthetic effect, while ensuring appropriate insulation thanks to the presence of the portions of seals 24a filling the deeper groove portions formed by the recesses 25a.

FIG. 9 illustrates the configuration of one of the plates 28 of a stack (not shown) capable of being produced for the implementation of another embodiment of the method according to the invention.

On this plate 28 has been machined a plurality of ribs 32, having the same width, separated by two pluralities of grooves of different depths 29 and 31 intended to be filled with a different colored substance, so as to combine the effects of decoration and insulation. In this case, the cutting would be carried out along the axes x-x ′ and y-y ′.

FIG. 10 illustrates a perspective view of a support 33 of the agglomerated type or of the so-called MDF type and provided with interlocking grooves and tongues to which several elements 14 are applied (although these could be replaced by elements such as the elements 15, 16 and 23 above) which provide a decorative effect thanks to the colored glue joints 3.

It is easy to verify that in the case of FIG. 1, the cutting into slices AB is carried out so as to remove the ribs 5, namely the means having served to define the thickness of the colored glue joint and to ensure its uniformity over the entire length; on the other hand, in the examples illustrated in FIGS. 3 and 5, the cutting of the sections A-B is carried out so as to include totally or in part the means according to the invention, namely the ribs (or flats) 8 and 13, respectively.

Of course, all the ribs illustrated in Figures 1, 3, 5, 7 and 9 can be made in one piece with the plates which carry them (as illustrated in the drawings) or attached; in addition, they can be continuous or discontinuous over their entire length.

Regarding the wooden plates used to make the different stacks 1, 10, 20, 30, etc ... these can be:
- of the same essence or of different essence,
- Made in a single piece of solid wood or formed by juxtaposition in at least two directions, in particular perpendicular, of a plurality of solid wood plates glued together, like the plates 11b of Figure 5 (of course, the glue between the different juxtaposed plates is not colored like the glue used between the superimposed plates),
- arranged with the fibers parallel or perpendicular to each other passing from one plate to the consecutive plate.

With regard to the colored adhesive, this can be rigid or flexible, after polymerization, the character of flexibility giving, to the wooden material according to the invention, the flexibility necessary to adapt to coatings of curved surfaces as well as to the expansions and retractions of the wood, of which it is composed, which are due to the hygrometric and thermal variations of the wooden slats, in particular when these are arranged in so-called "end" wood.

As is apparent from the above, the invention is in no way limited to those of its modes of implementation, embodiment and application which have just been described more explicitly; on the contrary, it embraces all the variants which may come to the mind of the technician in the matter, without departing from the scope, or the scope, of the present invention. In particular, as regards the upper limit of the adhesive joints (in particular when the ribs 5 and 22 are used as means making it possible to obtain a predetermined thickness for these joints which is also uniform over their entire length) between the adjacent lamellae elements obtained by the process according to the invention, this is essentially imposed by the cohesion properties of the adhesive used as well as by the resistance over time of these properties. In addition, the compression of each stack aiming to secure by bonding the superimposed plates, and therefore the adjacent lamellae of the material obtained by cutting slices, according to the arrangements which have been explained above, is in any event less than the crushing of the fibers of the wood used (therefore, variable with the density of the species of wood) and is carried out at a temperature between room temperature and 120 ° C, and even more, according to the techniques used, although the values are a function of the type of glue used.

Of course, the colored glue joints can be of the same color or of different colors, distributed among the different joints and even in the same joint, depending on the desired aesthetic effects, and produced from a rigid or flexible adhesive; in the case where the adhesive is flexible, it may be of the expanded type.

In addition, when the ribs are attached, they can be made, not only of wood, but also of cardboard or based on non-compressible synthetic or natural material (s).

With regard to the use of the material obtained using the method according to the invention, it should be noted the manufacture of facing objects, the decoration of flat or curved surfaces as well as construction in general.

It should also be noted that the depth of the recesses 25a is essentially limited by the resistance properties of the lamellae which are fitted with them.

In addition, the thickness of the wooden strips can vary within a relatively wide range of values, for example between 1.5 and 100 mm and even more depending on the needs and the intended applications.

Of course, in the example of FIG. 3, the lower limit (not included in the range of values) for the thickness of the joint 3 of colored glue is constituted by the small thickness of glue which is applied to the ribs 5 and which remains after pressing the stack, of the order of 0.01 mm.

Claims (10)

1.- Method of manufacturing a material (14, 15, 16, 23) consisting of a plurality of adjacent wooden strips (2′a, 2′b, ...; 6′a, 6′b, ...; 11′a, 11′b ...; 21′a, 21′b, ...;) separated from each other over their entire height and over their entire length by a colored glue joint (3, 9 , 19, 24) joining the lamellae together, which process comprises the following operations:
- superimposition of a plurality of wooden plates (2a, 2b, ...; 6a, 6b, ...; 11a, 11b, ...; 21a, 21b ...;) after having spread a layer of glue colored on at least one side of each plate,
- pressing of the stack thus obtained,
- cutting of this stack, preferably perpendicular to the plane defined by it, in slices (AB) whose width corresponds to the height of the strips, so as to obtain the aforementioned material,
and is characterized in that each of the plates of the aforementioned stack is provided, on at least one face thereof, with means (5, 8, 12, 13, 22, 32) making it possible to obtain a thickness of colored glue between superimposed plates of the above-mentioned stack, and therefore a thickness of the joint (3, 9, 19, 24) between adjacent lamellas of the aforementioned material, which has a predetermined value, variable within an appropriate range, and which is uniform over the entire length of the plates, and therefore of the strips. 2.- Method according to claim 1, characterized in that the aforementioned means are constituted by at least a plurality of longitudinal ribs (5, 8, 12, 13, 22, 32) spaced apart, whose height is a function of l aesthetic effect and / or glue economy sought, namely the thickness of the colored glue joint (3) between adjacent lamellae, each layer of colored glue being spread over the aforementioned ribs (5, 8, 12-13, 22, 32) and in the grooves (4, 7, 17, 18, 25, 29, 31) separating two adjacent ribs. 3.- Method according to claim 2, characterized in that, in the grooves (25c) separating two adjacent ribs (22) are formed deeper recesses (25a) communicating with the corresponding grooves (25c) and intended to be filled by an adhesive material (27), also having acoustic and / or thermal insulation properties. 4.- Method according to any one of claims 2 or 3, characterized in that each slicing (AB) is carried out so as to remove the ribs (5, 22) and to essentially include a groove or groove (4, 25) separating two adjacent ribs, the ribs being relatively narrow with respect to the grooves or grooves which separate them. 5.- Method according to claim 2, characterized in that each plate comprises a first (12) and a second (13) plurality of ribs of different widths, each rib (12) of the first plurality being separated, from side and d 'other, by two grooves (17, 18), having the same depth or different depths and separating, jointly, each rib of said first plurality of two ribs of said second plurality, and in that each slicing AB- is made so as to essentially include a rib (13), belonging to said first and second pluralities and preferably having the widest width, as well as the grooves (17, 18) which delimit it, while removing the other ribs, of width lesser (12). 6.- Method according to claim 2, characterized in that each plate comprises a single plurality of ribs (8) separated by grooves (7), and in that each slicing (AB) is performed so as to include essentially a rib (8) and a groove (7). 7.- A method according to any one of claims 1 to 6, characterized in that said ribs are made in one piece with the plates which carry them or attached thereto. 8.- Method according to any one of claims 1 to 7, characterized in that said ribs are continuous or discontinuous. 9 .- Wooden material, consisting of a plurality of adjacent wooden strips separated from each other over their entire height and over their entire length by a colored glue joint securing the strips together, characterized in that it is obtained at using the method according to any one of claims 1 to 8. 10.- Use of the material according to claim 9, obtained using the method according to any one of claims 1 to 8 for the manufacture of facing objects, decoration of flat or curved surfaces as well as for construction.

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