JPH11226913A - Method for dyeing woody veneer and manufacture of artificial decorative veneer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a transfer portion having an intermediate color tone of both a summerwood and a springwood at a boundary therebetween by superposing many sets of superposed two veneers so that surfaces of the both coated with dyes are brought into contact with one another, and repeatedly compressing and releasing the compression by a press, thereby penetrating the dye component interiors of the both. SOLUTION: A woody veneer P having a water content of a fiber saturation point or more is repeatedly compressed and released from the compression at free water or solvent water of dye D in the veneer to move it from a surface to an interior of the veneer. Simultaneously, a dye component is also moved into the veneer. Thus, if the veneer P having the water content of the fiber saturation point or more is used, a dyed single material for expressing a transfer from a springwood to a summerwood having a small gradient of a concentration change is obtained. Since the single material is impregnated with the dye D only from a coating surface of the dye D, the coated surfaces of the single materials are aligned in a predetermined direction, adhesively laminated to manufacture a flitch. And, the flitch is sliced in a direction intersecting with the laminated surface to obtain a decorative veneer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to housing equipment, furniture,
Wood veneer used for surface decoration of building interior materials etc.
The present invention relates to a method of dyeing a veneer and a method of manufacturing a wood decorative veneer (hereinafter, also simply referred to as a veneer) manufactured using the veneer dyed by the dyeing method.

[0002]

2. Description of the Related Art A decorative veneer obtained by thinly slicing a so-called natural precious wood, which is selected from natural woods and has an excellent appearance, has been often used for surface decoration of housing equipment, furniture, building interior materials and the like. Was. Wood that deserves a reputation as a so-called precious wood is characterized not only by its color, but also by the delicate grain pattern formed by annual rings, and the design formed by the combination of color and grain pattern is highly evaluated. is there.

However, in recent years, natural precious wood resources have been depleted, and prices have risen accordingly. Therefore, instead of natural precious wood, relatively inexpensive and large-amount available wood, such as southern timber, has been replaced with a slicer or wood. Veneers that have been thinly sliced by rotary lace are bleached or bleached as necessary, and then dyed to resemble natural precious wood.

[0004] However, wood that is relatively inexpensive and can be obtained in large quantities, such as southern lumber, has a wide grain width and a large or monotonous grain pattern, or most of the wood grain is not clear. It is far from aesthetic. Therefore, simply dyeing these veneers cannot create a high-quality feel like a natural precious wood. For this reason, recently, artificial veneers obtained by dyeing raw veneers made from these inexpensive wood, laminating and bonding them in the thickness direction to form flitches, and slicing them thinly in the direction intersecting the laminating surface are obtained. Veneer veneers have come into practical use.

That is, the veneer veneer obtained from these inexpensive timber such as southern timber is dyed in a color tone corresponding to the spring lumber part of a natural precious wood to be expressed, and in a color tone corresponding to the autumn lumber part. This is intended to obtain a wood veneer veneer very similar to a natural veneer veneer by thinly slicing flitches obtained by alternately laminating and bonding the flitches in a direction intersecting the lamination surface.

[0006] The thickness of the veneer veneer, such as a raw material of the southern seawood, is set with reference to the grain width of the natural precious wood to be expressed. Further, it is usually used after bleaching or bleaching before dyeing in order to make the color tone of the natural veneer to be reproduced as close as possible and to keep the color tone of the veneer after dyeing within a certain range.

However, as described above, by slicing a flitch obtained by alternately laminating and bonding a veneer veneer dyed in a color corresponding to the spring lumber of a natural precious wood and a veneer colored in a hue corresponding to the autumn lumber. The obtained decorative veneer has a sharp change in color at the boundary between the veneer of the spring color and the veneer of the autumn color, and the boundary between the two is clear.

However, in the decorative veneer of natural precious wood, the transition from the spring lumber to the autumn lumber is not so clear.
In the middle there is a transition where the color tone gradually changes. Therefore, simply stacking veneers dyed by the usual dyeing method and slicing them, like the wood of natural precious wood,
It is not possible to obtain a veneer veneer having a transition portion exhibiting a neutral color between the spring and autumn wood parts.

[0009] On the other hand, instead of preparing a light veneer representing the spring wood part and a dark veneer representing the autumn wood part, an artificial decorative veneer is manufactured using the same dyed veneer. There is also a known method. That is, a veneer dyed by a conventional dyeing method according to a conventional technique is dyed densely near the surface layer and the back surface layer where the dye penetrates well, and is gradually dyed thinner toward the inside. FIG. 3 or FIG. 4 schematically shows a gradient of a density change of a grain of a veneer obtained by slicing a flitch obtained by laminating a plurality of the dyed veneers. In addition to the portion and the dark portion corresponding to the autumn material portion, a transition portion having an intermediate color is formed.

However, when the grain of the natural precious wood is observed more closely, the transition of the intermediate color from the autumn lumber to the spring lumber is narrow, and the gradient of the density change is large. Or,
In some cases, the transition is hardly observed. On the other hand, the width of the transition from the spring timber to the autumn timber is much wider than the width of the transition from the autumn timber to the spring timber, and the gradient of the concentration change is extremely small. Recognize.

Since the veneer is dyed by dipping the veneer in a dye, the front and back of the veneer are dyed in the same manner. Therefore, even if this is laminated and bonded, the width of the transition from the autumn lumber to the spring lumber becomes the same as the width of the transition from the spring lumber to the autumn lumber, which is unique to natural precious wood as described above. Can not express the delicate wood grain feeling. On one side of veneer, polyethylene resin etc.
A method of forming a waterproof coating film and giving a difference in the dyeing concentration between the front and back sides is also conceivable, but forming a coating film on the veneer surface requires time and effort such as drying the veneer, and this method When laminating and bonding veneers dyed by the method described above, there is a problem that a sufficient adhesive force cannot be obtained unless a waterproof coating film is removed, which is too laborious and impractical.

As means for solving this problem,
Two inventions are described in JP-A-55-11864. According to the first invention, a dyed veneer having a gradient of density change such that the surface layer becomes darker and becomes lighter toward the center layer is produced, and one surface of the veneer is scraped off so that the surface layer becomes darker. A back veneer is made with a light colored cutting veneer, and a plurality of the veneer veneers are stacked via an adhesive layer such that the surface layers are directed in the same direction, and the flitch of the laminate is sliced to form a veneer veneer. How to get.

According to a second aspect of the present invention, the above-mentioned cut veneer and a second dyed veneer dyed in the same color as the back surface layer of the cut veneer are produced, and the second veneer is cut on the back surface of the cut veneer via an adhesive layer. 2 are laminated to form a set, and a plurality of the laminated veneers are laminated via an adhesive layer such that the surface layers of the cut veneers are directed in the same direction, and the flitch of the laminate is sliced to form a decorative veneer. Is a way to get

In the above two inventions, a part of the dyed veneer is cut and cut.
Since it must be removed, there is a disadvantage that the yield of the dyed veneer is significantly reduced.

[0015]

SUMMARY OF THE INVENTION According to the present invention, a transition portion having an intermediate color tone is formed at a boundary between an autumn lumber part and a spring lumber part in a wooden artificial veneer by the method described below. The second problem is that, in the artificial veneer veneer, the width of the transition portion from the spring lumber to the autumn lumber can be reduced without decreasing the yield of the veneer from the autumn lumber to the spring lumber. That is, it is formed wider than the width of the transition portion.

[0016]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems by a method of dyeing from only one surface of a veneer described below. That is, first, a large number of veneers to be dyed are prepared, and a dye of the color tone of the target natural precious wood is applied to one surface of each veneer.
Then, the two veneers are overlapped so that the surfaces to which the dye has been applied are in contact with each other. In this way, a plurality of veneers, each of which is a set of two, are superposed and repeatedly pressed and decompressed by a press machine to allow the dye component to penetrate inside. Moisture in wood has a property of moving from a portion having a high moisture content to a portion having a low moisture content so that the moisture content inside becomes uniform even when the wood is left in a natural state. In particular, since the free water inside the wood is easy to move, a single plate with a water content equal to or higher than the fiber saturation point where free water exists can be easily moved by repeatedly pressing and releasing by a press machine. Can be done.

Since a part of the dye component moves from the surface to the inside while fixing a part of the veneer to the veneer, the dye component is gradually dyed in a light color from the surface of the veneer to the inside. Since the present invention mainly aims to move the dye together with free water that easily moves inside the veneer and to penetrate the inside of the veneer, the water content of the veneer is higher than the fiber saturation point. Is desirable. However, when dyeing a portion of the veneer very close to the surface, or when the veneer is thin, even without free water, the solvent water of the dye may be sufficient,
In such a case, free water is not necessarily required, but as described later, when laminating and bonding the veneer after dyeing, and
In order to adjust the moisture content of the decorative veneer, which is the ultimate goal, it is preferable that the raw veneer contains free water as described below.

[0018]

For the above reasons, in a preferred embodiment of the present invention, first, a veneer having a water content equal to or higher than the fiber saturation point is used, and free water in the veneer or solvent water of a dye, or Both the free water inside the veneer and the solvent water for the dye are repeatedly pressed and decompressed to move from the inner surface of the veneer to the inside, and at the same time the dye component is also moved to the inside of the veneer. Thus, if a veneer having a water content equal to or higher than the fiber saturation point is used,
A dyed veneer can be obtained that can express the transition from the spring wood to the autumn wood with a small gradient of concentration change. In this case, if the water content of the surface opposite to the surface to which the dye is applied is set to be lower, the dye component easily moves into the veneer together with the moisture.

Since the dye permeates only from the surface on which the dye is applied to the veneer dyed by the above method, the veneer is manufactured by laminating a large number of the veneers with the surface on which the dye is applied aligned in a certain direction and laminating and adhering. Then, when the flitch is sliced in a direction intersecting the lamination plane, a decorative veneer as shown in FIG. 6 is obtained.

When the veneer is dried until the moisture content reaches the fiber saturation point and then a dye is applied to the veneer surface, only the portion very close to the surface can be dyed. By reducing the water content of the veneer to the fiber saturation point, free water in the veneer disappears, so that the dye component is absorbed near the veneer surface together with the solvent water of the dye, making it difficult to penetrate into the interior. Only the part very close to the surface can be dyed, and the transition from the autumn wood part to the spring wood part with a large gradient of concentration change can be expressed.

For a veneer having a water content equal to or higher than the fiber saturation point and containing free water, first, one surface is dyed with a small gradient of concentration change so as to correspond to a transition from a spring wood portion to a fall wood portion of a natural precious wood. Then, after drying until the water content reaches the fiber saturation point, then, the part very close to the surface of the other side,
As in the transition from autumn wood to spring wood, the dye is dyed so that the gradient of concentration change is large. In this manner, for the front and back surfaces of the veneer, the front surface or the back surface of the veneer dyed so that the degree of dye permeation is different is aligned in a certain direction, and a large number of the veneers are laminated and adhered to produce a flitch. By slicing in the direction intersecting the lamination plane, a decorative veneer as shown in FIG. 5 is obtained.

Also, by increasing the concentration of the dye,
Solvent water of the dye can be reduced, and the permeation of the dye component into the veneer can be variously changed by increasing / decreasing the pressing pressure, pressing time, the number of times of pressing / releasing, etc. . Therefore, even when the veneers having the same veneer moisture content are used, the transition from the autumn lumber to the spring lumber and the transition from the spring to the autumn lumber are expressed by changing the dye concentration and the like. be able to.

As described above, in the present invention, by adjusting the moisture content of the veneer, the dye concentration, the amount of dye applied, the pressing pressure, the pressing time, and the number of repetitions of pressing / releasing, Since the gradient of the concentration change can be changed in various ways, the transition from the autumn wood part to the spring wood part where the gradient of the concentration change is large and the transition part from the spring wood part to the autumn wood part where the gradient of the concentration change is small are Both can be represented by various gradients of concentration change.

The dyed veneers are then superposed and laminated in the thickness direction, and usually, a moisture-curable urethane resin-based adhesive is used for lamination. When such a moisture-curable resin adhesive is not used, it is difficult to bond the veneer without drying the veneer. Therefore, a moisture-curable resin adhesive is used except in special cases.

Since the moisture-curable resin adhesive is cured by absorbing moisture in the veneer, a certain amount of free water exists near the veneer surface, or the veneer is laminated. When pressed from the top, a certain amount of moisture does not ooze out of the interior of the veneer, so that the adhesive strength is not exhibited. Further, when the water content is too low, especially when the water content is below the fiber saturation point, the veneer starts to shrink, wrinkles, bends, warpage, etc., and irregularly deform, so that the water content is higher than the fiber saturation point. Better.

However, if the surface of the veneer is too wet and the veneer surface is wet, the curing reaction is started at the same time as applying the adhesive to the veneer surface. The adhesive strength after lamination decreases.

Therefore, the water content of the dyed veneer suitably contains a certain amount of free water, and the surface is wet and drained. Such moisture content is above the fiber saturation point of the wood veneer and less than about 90%.
Desirably, the water content is not less than the fiber saturation point and not more than 60%.

In the present invention, as described above, by adjusting the moisture content of the veneer, the dye concentration, the amount of dye applied, the pressing pressure, the pressing time, and the number of repetitions of pressing / releasing,
The gradient of the concentration change can be varied, but if the moisture content of the dyed veneer is above the fiber saturation point and below 90%, the veneers are laminated and sliced. The decorative veneer thus obtained also has substantially the same water content as the above, and can be bonded as it is as a wet veneer to a decorative plate substrate by hot pressing with a hot press machine.

When the water content of the decorative veneer is too high, the adhesive is weakened by the moisture in the decorative veneer when hot-pressing and bonding to the decorative veneer substrate, and the adhesive strength is reduced. Conversely, if the water content is too low, especially when the fiber saturation point or less, shrinkage of the veneer starts, wrinkles, bends, warpage, etc. occur, irregularly deformed, or cracks occur In addition, when a decorative veneer is attached to a decorative substrate, defective products increase.

The upper limit value of the pressing pressure varies depending on the species of tree, but is preferably about 5 to 50 kg / cm ² . 5 kg
/ Cm ² or less, it takes too much time for the dye to penetrate. When it is at least 50 kg / cm ² , a normal wood veneer will cause permanent deformation of the wood cells due to pressing, resulting in a reduction in thickness. For example, in soft conifers such as Uchiji cedar and Ezo pine, pressing repeatedly at 20-30 kg / cm ² or more causes a reduction in thickness.
Repeated pressing at g / cm ² or more results in thickness reduction.

The lower the moisture content of the veneer before dyeing, the faster the dye absorption. However, the water content of the veneer can be easily lowered to the fiber saturation point (depending on the tree species, but 25 to 35%). It takes time and effort. In a preferred embodiment of the present invention, as described above, it is not necessary to lower the water content of the veneer to a value lower than the fiber saturation point, and adjust the dye concentration, the dye application amount, the pressing pressure, etc. It is characterized in that it is possible to express a transition part from a spring timber part to a spring timber part and a transition part from a spring timber part to an autumn timber part.

However, if there is too much free water in the veneer or too much solvent water for the dye, when the veneers coated with the dye are overlaid and pressed together, Since a part of the water containing the dye is squeezed out and leaks out, there is an adverse effect even if there is too much free water or the solvent water of the dye. The appropriate moisture content also depends on the pressing pressure when the dye is allowed to penetrate into the interior of the veneer, but the range is not less than the fiber saturation point and up to 90%, preferably the fiber saturation point, as described above. Above and up to 60%. However,
The raw material veneer obtained from a South Sea material or the like is usually higher than the above-mentioned moisture content unless labor such as air drying is required. Therefore, although it takes a certain cost to keep the moisture content of the veneer within the above range, it can be implemented at a low cost by the following method.

That is, before applying the dye, a number of veneers to be dyed are overlaid and pressed. The pressing pressure is set slightly higher than the pressing pressure when the dye is allowed to penetrate into the interior of the veneer. The reason for setting the pressure slightly higher than the pressing pressure when penetrating the dye into the interior of the veneer is that the solvent water of the dye is replenished by applying the dye later. In order to keep a small amount of free water. If the veneer is clamped and there is too much free water, it will leak from the side of the veneer that is overlaid. The leaked free water is absorbed and removed by a suction pump. At this time,
When the pressing pressure is set to the maximum value within a range where permanent distortion does not occur, most of the free water in the veneer is removed, and a veneer having a water content close to the fiber saturation point is obtained. In addition, as described later, in the case of pressing, a method in which a sheet having a water-absorbing property such as a dried felt, paper, etc. is sandwiched can be used to obtain a veneer having a water content substantially at a fiber saturation point. Can also. If the pressing pressure is adjusted to be lower than the above, a veneer having a water content higher than the fiber saturation point and an appropriate amount of free water remaining can be obtained.

If the pressing direction of the press used for the pressing is horizontal, the free water leaking from the side surfaces of the squeezed and laminated veneers falls naturally, so that a suction pump is not necessary. However, it takes a certain amount of time for the leaked free water to completely fall by itself, and thus the use of a suction pump increases the work efficiency. If the pressure is released before the leaked free water is removed, the water remaining on the side surfaces of the laminated veneers will be absorbed into the veneers again, so care must be taken.

When a veneer having a moisture content adjusted by the above method is prepared, a dye is applied to one surface of these veneers, and the veneers are superposed so that the dye-coated surfaces are in contact with each other. In order to make the dye easily penetrate into the veneer, it is necessary that the veneer has a water gradient. You should be there.

That is, if there is a water gradient such that the water content decreases from the surface on which the dye is applied to the opposite surface, the dye easily penetrates. Even if there is no water gradient on the veneer before dye application, the water content of the dye-coated surface becomes higher than the water content of the opposite surface due to the water content of the dye. However, the more the water gradient, the faster the dye penetration.

Before applying the dye, it is conceivable that the surface to which the dye is applied is turned upside down and a water gradient is imparted by air-drying or heating. If the water is not used for the dyeing process within a short time, the applied water gradient disappears.

Therefore, as shown in FIG. 2, the veneers to which the dye is not applied are brought into contact with each other at the time of pressing at the time of dyeing, as compared with the case where the moisture gradient is imparted to the veneer before the application of the dye. A sheet of absorbent material, such as felt or paper, is sandwiched between the two surfaces, and absorbs moisture from the surface opposite to the surface on which the dye is applied, creating a water gradient and a single dye. It is good to promote penetration into the inside of the board.

Of course, the operation of imparting the above-mentioned water gradient to the veneer by the above method may be performed before the application of the dye, or both before and after the application of the dye.

The method of imparting a water gradient to a veneer before dye application is not limited to the above method. For example, far infrared rays may be emitted to only one surface of the veneer, or two veneers may be sandwiched between hot plates. Any known method such as heating from above and below may be used.

[0041]

As described above, according to the method of the present invention, it is possible to produce a dyed veneer whose concentration gradually decreases from the surface of the veneer to the interior of the veneer with a simple apparatus. Can,
In addition, the yield of the veneer is not reduced. Further, by laminating and bonding the veneers and slicing the veneers thinly in a direction intersecting with the laminating plane, a transition between the autumn lumber part and the spring lumber part can be expressed like a natural precious wood.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a dyeing method of the present invention.

FIG. 2 is an explanatory view showing the dyeing method of the present invention.

FIG. 3 is a schematic view of a grain of artificial veneer veneer according to the prior art.

FIG. 4 is a schematic view of a grain of artificial veneer veneer according to the prior art.

FIG. 5 is a schematic view of a grain of a decorative veneer according to the present invention.

FIG. 6 is a schematic view of a grain of a decorative veneer according to the present invention.

[Explanation of symbols]

 P Wood veneer D Dye F Sheet-shaped hygroscopic material

[Procedure amendment]

[Submission date] February 8, 1999

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

Claims (6)

[Claims] 1. A method for dyeing a wooden veneer with a dye, the method comprising: applying a dye to only one surface of the wooden veneer so as to overlap the dye-coated surfaces so as to face each other; Dyeing of wood veneers characterized by laminating multiple sets of wood veneers in the thickness direction and repeating the pressing and decompression from the thickness direction to allow dyes to penetrate into the wood veneers and dye them Method. 2. A method of dyeing a wooden veneer with a dye, the method comprising: applying a dye to only one surface of the wooden veneer so that the surfaces to which the dye is applied face each other to form a set; A set of laminated wood veneers and a sheet of water-absorbing material are alternately laminated in the thickness direction multiple times, and the dye is penetrated into the wood veneer by repeating pressing and releasing from the thickness direction. A method for dyeing a wooden veneer, characterized by dyeing with wood. 3. The method for dyeing a wooden veneer according to claim 1, wherein the pressing pressure is 5 to 50 kg / cm ² . 4. The veneer having a moisture content of not less than the fiber saturation point of the tree species and not more than 90%.
The method for dyeing a wooden veneer according to the above. 5. A wooden veneer dyed by the method according to claims 1 to 4, with the dye-coated surface oriented in a certain direction,
A method for producing a wood veneer, wherein a flitch is manufactured by laminating and bonding a large number of sheets in a thickness direction, and the flitch is sliced in a direction intersecting a lamination surface. 6. The method according to claim 1, wherein a plurality of wooden veneers are dyed on the front and back surfaces so that the dye penetration degree on the front and back surfaces is different. A method of manufacturing a veneer made of wood, characterized in that a plurality of sheets are laminated and bonded in the thickness direction to produce a flitch, and the flitch is sliced in a direction intersecting the laminating surface.