JP2000153510A - Compressed timber and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressed timber capable of expressing a protrusion and recess surface extended in a direction crossing a direction of extending a woodgrain on a surface and having a smooth surface. SOLUTION: The compressed timber 11 is molded on its surface in a uniform waveform shape at an interval and an amplitude of one wavelength of recesses 12 and protrusions 13. The timber 11 is compression formed so that a direction of extending a woodgrain 14 and a direction of extending the recesses 12 and protrusions 13 are substantially perpendicularly crossed. The timber is mounted so that a metal plate 20 is brought into contact with the timber on the timber mounted on a support base 9 in a pressure resistant container and further protruding strips 22 of a die 21 are brought into contact with the plate 20 on the plate 20. The timber is compression formed by pressing from above the die 21 by a hydraulic device, and the plate 20 having a predetermined thickness, required rigidity and smooth front and rear surface square shapes is interposed between the timber and the die 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to compressed wood that can be made to have a smooth wavy shape by compression-molding the wood, and a method of manufacturing the same.

[0002]

2. Description of the Related Art When a soft material such as cedar is used as an interior material, there is a problem that the material is easily damaged and is weak against impact.
Applications are limited. Therefore, a compression molding technique of wood using high-temperature and high-pressure steam, that is, a technique of compressing wood softened by steam and fixing the deformation by treating the wood with high-temperature steam has been established.

By using dies having various surface shapes during compression molding, various shapes can be imparted to the surface of wood. For example, Japanese Patent Application Laid-Open No. 10-2356
No. 19 discloses compressing wood using a metal mold having an uneven shape. A decorative pattern or the like is formed on the surface of the compressed wood.

[0004]

However, in wood before compression molding, the position and surface shape of the wood,
In compression, cracks may occur on the surface of the wood depending on the compression method and the position of the mold. For example, when wood is compressed by a metal mold having an uneven shape, a strong compressive force acts on a position where the wood becomes a concave portion, and a tensile force acts on a position where the wood becomes a convex portion toward the concave portion. For this reason, there has been a problem that the wood fiber cannot follow the tensile force in the portion where the tensile force has acted, the fiber is broken, and the surface of the compressed wood is cracked.

Further, when compressed so as to exert a tensile force in the direction in which the fibers of the wood extend, irregularities can be formed in the wood, but it is difficult to produce compressed wood having a smooth surface. was there. Furthermore, after the compression molding, a work step of cutting the cracked portion to prepare the surface of the compressed wood is required, which causes a problem that the production time of the compressed wood is lengthened.

The present invention has been made by paying attention to such problems existing in the prior art. The purpose is to be able to express irregularities on the surface that extend in a direction that intersects the direction in which the grain extends.
Its purpose is to provide a smooth compressed wood surface. Another object is to produce compressed wood in which the direction in which the grain extends and the direction in which the unevenness extends can be easily manufactured, and the compressed wood can be prevented from cracking on its surface. It is to provide a manufacturing method.

[0007]

According to a first aspect of the present invention, there is provided a compressed wood according to the first aspect of the present invention, wherein the direction of extension of the uneven portion on the surface of the wood formed by compression molding is such that the grain of the wood is extended. Is formed so as to intersect with the direction in which.

According to a second aspect of the present invention, in the compressed wood according to the first aspect, the uneven shape of the uneven portion is a wave shape. In the method for manufacturing compressed wood according to the third aspect of the present invention, the wood is steamed and softened, and the wood is compression-molded by interposing a compressively deformable plate between the wood and a mold, and the shape is maintained. After the shape is fixed by heating with high temperature steam as it is, it is cooled and dried.

According to a fourth aspect of the present invention, there is provided a method of manufacturing compressed wood according to the third aspect, wherein the surface of the mold is formed in an uneven shape, and the direction in which the unevenness extends and the shape of the wood before compression molding. The wood is compressed by a mold so that the direction in which the wood extends is crossed.

According to a fifth aspect of the present invention, there is provided a method for manufacturing compressed wood according to the third or fourth aspect, wherein the irregularities on the mold surface are formed in a wavy shape, and the compression-molded wood is formed. It forms a smooth wavy shape on the surface.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, a plate-shaped compressed wood 11 is formed into a rectangular shape, and the surface thereof is formed into a corrugated shape in which the intervals and amplitudes of one wavelength are uniform by a concave portion 12 and a convex portion 13 which constitute an uneven portion. ing. If the direction in which the grain 14 extends is the fiber direction 15, the compression molding is performed so that the extending directions of the concave portion 12 and the convex portion 13 are substantially orthogonal to the fiber direction 15.

The convex portion 13 and the concave portion 12 of the compressed wood 11 are formed in a substantially arc shape, and the waveform thereof is smooth.
In addition, all edges of the compressed wood 11 are chamfered as necessary, and the edges are trimmed.

[0013] As shown in FIG.
The direction in which the grain 14 extends is referred to as a fiber direction 15, and the direction perpendicular to the fiber direction 15 is referred to as a tangential direction 17. Also,
The thickness direction of the wood 16 is defined as a radiation direction 18. The length in the fiber direction 15 and the length in the tangential direction 17 are arbitrarily set in accordance with the dimensions of a mold used in compression molding.

As shown in FIG. 1, the angle formed by the extending direction of the concave portion 12 and the convex portion 13 formed after the compression molding and the extending direction of the grain 14 is preferably set in the range of 30 to 90 degrees. , Approximately 90 degrees. When this angle is in the range of 30 to 90 degrees, the concave portion 1 formed on the grain 14 and the surface of the compressed wood 11
The compressed wood 11 having good design properties can be obtained by expressing the projections 2 and the projections 13 to intersect with each other. By changing this angle, the compressed wood 1
Various types of compressed wood 11 having different angles formed by the extending directions of the concave portion 12 and the convex portion 13 on the surface 1 can be manufactured.

When the angle is less than 30 degrees, the recess 12
In addition, the extending direction of the protrusion 13 and the grain 14 becomes substantially the same, and the design is poor, which is not preferable. On the other hand, when the angle exceeds 90 degrees, compressed wood 11 having good quality can be obtained in the range of 90 to 150 degrees as in the case of the angle of 30 to 90 degrees, but exceeds 150 degrees. Then, the desired compressed wood 11 cannot be obtained.

Next, an apparatus for manufacturing the compressed wood 11 will be described. Although not shown, this device is a pressure-resistant container equipped with a steam generator and capable of injecting high-temperature and high-pressure steam into the container through a steam pipe from the steam generator. The pressure vessel can be hermetically sealed and evacuated, and has a hydraulic press device 25 inside. further,
As shown in FIGS. 3 to 5, the hydraulic press 25
Is a square plate-shaped support table 19 on which the wood 16 is placed, a square metal plate 20 as a compressible deformable plate material placed on the wood 16 on the support table 19, and And a mold 21 placed on the mold.

The support base 19 is formed of a stainless steel plate having a thickness that can withstand compression. When the wood 16 is compression-molded, it receives a compressive force from above.

The metal plate 20 has a required rigidity, and is made of a flat stainless steel plate whose front and back surfaces are formed smooth before compression. Its thickness is 0.1-1m
It is preferably set to m, more preferably set to 0.1 to 0.3 mm, and particularly preferably set to 0.2 mm. When the thickness of the metal plate 20 is smaller than 0.1 mm, when the wood 16 is compressed, the concave portion 12 and the convex portion 13 can be formed on the surface of the wood 16 so that the difference therebetween becomes large. However, it is not preferable because the metal plate 20 cannot follow the compression and breaks to cause cracks or the like on the surface of the compressed wood 11. On the other hand, when the thickness of the metal plate 20 is greater than 0.3 mm, the shape of the mold 21 is not represented on the metal plate 20 when compressed, so that the compressed wood 11 can reliably represent the shape of the mold 21. Not preferred.

The thickness of the metal plate 20 is 0.1 to 0.3.
When it is within the range of mm, when compressed, the metal plate 20 can flexibly correspond to the shape of the mold. Therefore, a shape corresponding to the shape of the mold 21 can be expressed on the surface of the compressed wood 11.

Further, when the metal plate 20 is made of stainless steel and has a thickness in the range of 0.1 to 0.3 mm, the metal plate 20 returns to its original flat shape when the compression is released. . When the thickness is about 1 mm, the deformation due to the compression can be forcibly returned to the original flat shape. Even when the metal plate 20 is an aluminum plate, deformation due to compression can be forcibly returned to the original flat shape. Therefore, since the metal plate 20 can be restored to a flat plate shape after the compression deformation, the metal plate 20 such as a stainless steel plate or an aluminum plate can be reused, and the manufacturing cost can be reduced.

Further, when the metal plate 20 is placed on the wood 16, the metal plate 20 is placed so as to be in close contact with the surface of the wood 16. Therefore, even if the metal plate 20 is deformed by compression, the front and back surfaces of the metal plate 20 are smooth, so that the surface of the compressed wood 11 can be made smooth.

The mold 21 made of an aluminum alloy having corrosion resistance has a plurality of ridges 2 having a plurality of arc-shaped cross sections on one surface thereof.
By forming 2 at a predetermined interval, concave ridges 23 having an arc-shaped cross section are formed between the ridges 22, for example, so as to draw a waveform having an interval of one wavelength of 40 mm and an amplitude of 3 mm. The mold 21 is used for giving a difference in the degree of compression to the wood 16 and forming a waveform on the surface of the wood 16. The compression is performed by pressing the mold 21 with a hydraulic device.

The grain 14 and the mold 2 of the wood 16 before compression molding
The angle formed by the direction in which one ridge 22 extends is set within a range of 30 to 90 degrees. Further, by changing the angle, the structure of the wood 14 is diversified, and various compressed woods 11 are formed.
Can be manufactured.

Next, in the compression molding of the wood 16, the wood 16 is first softened in the pressure vessel. That is, after the pressure vessel is closed and the inside thereof is evacuated in advance, saturated steam of high temperature and high pressure is injected into the vessel. When the wood 16 is steamed in the temperature range of 100 to 150 ° C. in this manner, the wood 16 absorbs high-temperature and high-pressure steam and the internal temperature rises. As a result, the wood 16 is rapidly softened.

Next, compression molding for forming a corrugation in the softened wood 16 is performed. This compression molding is shown in FIG.
As shown in FIG. 3, a metal plate 20 is placed on a wood 16 placed on a support 19 in a pressure-resistant container so as to be in close contact with the wood 16, and a metal mold 21 is further placed on the metal plate 20. The ridge 22 is placed so as to be in contact with the metal plate 20. Then, as shown in FIG.
The compression molding of the wood 16 is performed by pressing from above.

At this time, the compression ratio is defined as the ratio of the thickness before compression to the thickness before compression minus the thickness after compression. When the wood 16 to be used is a coniferous board such as cedar or cypress, the compression ratio at the position corresponding to the recess 12 is 35.
It is preferably set within the range of 50% to 50%.
It is particularly preferable to set within the range of 5%. The compression ratio varies depending on the specific gravity and characteristics of the wood 16 used.

If the compression ratio is less than 35%, the compression ratio of the protrusion 13 of the obtained compressed wood 11 becomes insufficient, and the protrusion 1
An uncompressed portion is formed on the surface of No. 3, and the appearance is unfavorably deteriorated. On the other hand, when the compression ratio exceeds 50%, the metal plate 20 does not follow the compression force and is not easily separated, which is not preferable. Further, the compression force acts too much on the wood 16 and the compressed wood 1
Shading is expressed on one surface, and the appearance deteriorates, which is not preferable.

When the surface of the wood 16 is compression-molded into a corrugated shape by the mold 21, a strong compressive force acts in the radial direction 18 on the concave portion 12 of the compressed wood 11, and further, the fiber direction from the convex portion 13 to the concave portion 12. A tensile force to 15 is applied, and the fiber near the vertex of the convex portion 13 is easily cut,
Cracks are likely to occur.

At this time, a square metal plate 20 having a predetermined thickness and a required rigidity between the wood 16 and the mold 21 and having a smooth front and back surface is adhered to the surface of the wood 16. It is interposed to be. Therefore, as shown in FIG. 5, when the wood 16 is compressed via the metal plate 20, the tensile force of the fiber acting on the projection 13 of the compressed wood 11 in the direction of the concave portion 12 is reduced by the metal plate 20 adhered to the wood 16. Focus on Therefore, as compared with the case where the metal plate 20 is not interposed, the tensile force in the fiber direction 15 from the convex portion 13 to the concave portion 12 of the compressed wood 11 is reduced. As a result, the fiber near the apex of the convex portion 13 of the compressed wood 11 is cut, thereby preventing the surface of the compressed wood 11 from being cracked.

Further, since the metal plate 20 has a flat plate shape and is compressed by the mold 21 from a state where the front and back surfaces are smooth, the position where the metal plate 20 of the compressed wood 11 abuts after compression is formed smoothly. Thus, compressed wood 11 having a smooth surface can be manufactured.

Next, a process for fixing the waveform of the compressed wood 11 is performed. This immobilization treatment is performed by heating to 170 to 200 ° C. with water vapor and maintaining the state for 30 minutes while maintaining the wave shape formed on the surface of the wood 16 in the pressure vessel. As a result, the waveform formed on the wood 16 by the water vapor is fixed.

Further, the supply of water vapor into the pressure-resistant container is stopped, and the water vapor in the container is discharged to the outside of the container.
The inside of the container is set to the same pressure as the atmospheric pressure. Next, by cooling the wood 16, the water vapor remaining inside the wood 16 is removed. Cooling is performed by natural cooling by air cooling or forced cooling by water cooling, and is cooled to 60 to 65 ° C.

The compressed wood 11 obtained by the above embodiment
Can be used for building materials, furniture and the like. The effects exerted by the above embodiment will be described below.

According to the compressed wood 11 of this embodiment, the recess 12 formed in the compressed wood 11 by compression molding
And the direction in which the protrusions 13 extend is substantially perpendicular to the fiber direction 15 in which the grain 14 extends,
Its surface is formed smoothly. Therefore, it is possible to provide the compressed wood 11 having a different appearance from the conventional one.

According to the compressed wood 11 of this embodiment, the surface of the compressed wood 11 is compression-molded into a smooth waveform. Therefore, the compressed wood 11 having a good appearance can be provided.

According to the compressed wood 11 of this embodiment, the angle formed by the extending direction of the concave portion 12 and the convex portion 13 formed after the compression molding and the extending direction of the grain 14 is 30 to
It is set within the range of 90 degrees. Therefore, compressed wood 11 having good design properties can be obtained. Also,
By changing this angle, it is possible to obtain various types of compressed wood 11 having different angles with respect to the grain 14 by the direction in which the waveform of the surface of the compressed wood 11 extends.

According to the compressed wood 11 of this embodiment, since the voids in the cells of the wood 16 are reduced and compacted by the compression molding, the strength and the hardness of the surface of the compressed wood 11 can be improved.

According to the method for manufacturing the compressed wood 11 of this embodiment, when the wood 16 is compressed, a metal plate having a predetermined thickness between the wood 16 and the mold 21 and having a required rigidity 20 is interposed so as to be in close contact with the surface of the wood 16. Therefore, when the wood 16 is compressed through the metal plate 20, the fiber pulling force acting on the protrusion 13 of the compressed wood 11 in the direction of the concave portion 12 concentrates on the metal plate 20 that is in close contact with the wood 16. Therefore, the tensile force in the fiber direction 15 from the convex portion 13 to the concave portion 12 is reduced, and the fiber near the apex of the convex portion 13 of the compressed wood 11 is cut, thereby preventing cracking on the surface of the compressed wood 11. can do. as a result,
The operation of cutting and shaping the crack can be omitted, and the manufacturing time of the compressed wood 11 can be reduced.

According to the method for manufacturing the compressed wood 11 of this embodiment, the thickness of the metal plate 20 is set in the range of 0.1 to 0.3 mm. Therefore, when compressed, the metal plate 20 can flexibly correspond to the shape of the mold 21. Therefore, a shape corresponding to the mold 21 can be expressed on the surface of the compressed wood 11.

According to the method for manufacturing the compressed wood 11 of this embodiment, the compression ratio at the position corresponding to the recess 12 of the compressed wood 11 is set to 35 to 50%. Therefore, it is possible to clearly express the difference between the concave portion 12 and the convex portion 13 of the compressed wood 11, and to prevent cracks and shading from occurring on the surface of the compressed wood 11, thereby preventing the appearance of the compressed wood 11 from being deteriorated. it can.

According to the method for manufacturing the compressed wood 11 of this embodiment, the thickness of the stainless steel plate 20
It is set within the range of 0.3 mm. Therefore, after the compression, the stainless steel plate 20 deformed by the compression naturally returns to the flat shape, so that the stainless steel plate 20 can be reused and the manufacturing cost can be reduced.

[0042]

[Examples] Hereinafter, the above embodiment will be described more specifically with reference to examples. As shown in FIGS. 3 to 5, a mold 21 made of an aluminum alloy and having a shape of drawing a wavelength having an interval of one wavelength of 40 mm and an amplitude of 3 mm was used. 50 mm in thickness in the radial direction 18 × length 15 in the tangential direction 17 as the wood 16
A cedar plate 16 having a length of 0 mm × fiber direction 15 and a length of 1200 mm was used, and a stainless steel plate 20 having a thickness of 0.2 mm was used as a metal plate 20 interposed between the cedar plate 16 and the mold 21.

The compression molding process was performed in a pressure vessel equipped with a hydraulic press device 25, into which high-temperature and high-pressure steam could be injected. The cedar plate 16 on the support 19 in the pressure vessel,
The stainless steel plate 20 and the mold 21 were placed in this order, and the pressure vessel was sealed. At this time, the stainless steel plate 20 is in close contact with the surface of the cedar plate 16.

After evacuating the inside in advance, saturated steam at a high temperature and a high pressure is injected, and the temperature is reduced to about 3 at about 120 ° C.
The cedar board material 16 was softened for 0 minutes. Thereafter, the mold 21 was compressed by a hydraulic device, and the cedar plate 16 was compressed via the stainless steel plate 20. At this time, the compression ratio at the position corresponding to the concave portion 12 of the compressed wood 11 is set to 40%, and the angle between the direction in which the grain 14 of the cedar board 16 extends and the direction in which the ridge 22 of the mold 21 extends is approximately 90. Degree.

While maintaining the shape of the cedar plate 16 as it is,
The temperature was raised to 80 ° C. and maintained for 30 minutes, and the shape of the cedar plate 16 was fixed. Thereafter, the inside of the pressure vessel was returned to the atmospheric pressure, and naturally cooled to 60 ° C., and the cedar plate 16 was taken out of the pressure vessel.

As a result, the extending direction of the grain 14 and the recess 1
2 and the direction in which the protrusions 13 extend are substantially perpendicular to each other, and the thickness of the recess 12 of the compressed wood 11 is 30 mm.
Was obtained about 2 mm.
In addition, the concave portion 12 and the convex portion 13 were formed in a smooth arc shape, and the surface was smooth without any cracks.

The present embodiment can be embodied with the following modifications. As shown in FIGS. 6 and 7, a metal round bar 26 or pipe is used instead of the mold 21, and the round bars 26 or pipes are arranged at equal or arbitrary intervals, and the thickness is appropriately adjusted. May be adjusted. Then, the round bar 26 may be compressed from above the round bar 26 or the pipe by a compression plate 27 made of stainless steel or the like. Also in the case of such a configuration, a smooth waveform can be formed on the surface of the compressed wood 11. Further, by changing the interval, the concave portion 12 and the convex portion 1 of the compressed wood 11 are formed.
3 can be arbitrarily set, and the difference between the concave portion 12 and the convex portion 13 can be adjusted by adjusting the thickness. Therefore, various types of compressed wood 11 can be manufactured. Furthermore, there is no need to manufacture a mold 21 having another type of uneven shape, and the manufacturing cost can be reduced.

In the present embodiment, the metal plate 20 may be changed to an aluminum plate or the like, or a plate made of a material such as a rubber plate that is not deformed while being flexibly deformed by compression. Also in this case, cracks can be prevented from being generated on the surface of the compressed wood 11, and the surface can be formed smoothly.

The design may be carved shallowly on one side of the metal plate 20 whose front and back surfaces are smooth by laser processing or the like, and the surface on which the design is carved may be brought into close contact with the surface of the wood 16 and compressed. With this configuration, the resulting compressed wood 1
The design of the metal plate 20 can be transferred to the surface of the first metal plate 20.

A part or the entire surface of the compressed wood 11 may be cut at a desired position. In the case of such a configuration, the decorative feeling can be changed by changing the grain 14 and the like of the compressed wood 11.

Further, the technical ideas that can be grasped from the above embodiment will be described below. -The compressible deformable plate is a thin metal plate.
6. The method for producing compressed wood according to any one of claims 5 to 5.

With this configuration, when the wood is compressed through the thin metal plate, the fiber pulling force acting on the convex portion of the compressed wood in the concave direction concentrates on the thin metal plate. Therefore,
The tensile force in the fiber direction from the convex portion to the concave portion is reduced. Therefore, it is possible to prevent the fiber near the apex of the convex portion of the compressed wood from being cut, and to prevent cracks from being generated on the surface of the compressed wood.

The thickness of the compressible deformable plate is set to 0.1.
The method for producing compressed wood according to any one of claims 3 to 5, wherein the thickness is set to 1 to 0.3 mm. With this configuration, cracks can be reliably prevented from being generated on the surface of the compressed wood, and the shape of the mold can be expressed by the compressed wood. Further, when the plate material is a stainless steel plate, the deformation due to the compression naturally returns to the original flat shape after the compression is released, so that the plate material can be reused and the manufacturing cost can be reduced.

[0054]

As described above in detail, according to the present invention, the following effects can be obtained. According to the compressed wood of the first aspect of the present invention, it is possible to express unevenness on the surface extending in a direction intersecting with the direction in which the grain extends, and to smooth the surface.

According to the compressed wood of the second aspect, in addition to the effects of the first aspect, it is possible to provide a compressed wood having a good appearance. According to the method for manufacturing compressed wood according to the third aspect of the present invention, compressed wood in which the direction in which the grain extends and the direction in which the unevenness extends can be easily manufactured, and cracks are generated on the surface thereof. Can be prevented.

According to the method for manufacturing compressed wood of the invention described in claim 4, in addition to the effect of the invention described in claim 3, in addition to the effects of the invention described above, the surface has unevenness extending in a direction intersecting the direction in which the grain extends. The expressed compressed wood can be easily manufactured.

According to the fifth aspect of the present invention, in addition to the effects of the third or fourth aspect of the present invention, the surface of the compressed lumber is smoothed to improve the feel. can do.

[Brief description of the drawings]

FIG. 1 is a partial perspective view showing compressed wood according to an embodiment.

FIG. 2 is a partial perspective view showing wood before compression molding.

FIG. 3 is a partial perspective view showing a compressed state of wood.

FIG. 4 is a side view showing a state before compression molding of wood.

FIG. 5 is a side view showing a state after compression molding of wood.

FIG. 6 is a side view showing a state before compression molding of wood using a mold of another example.

FIG. 7 is a side view showing a state after compression molding of wood using a mold of another example.

[Explanation of symbols]

11: compressed wood, 12: recesses forming the uneven portion, 13:
Convex portions forming the concave and convex portions, 14: wood grain, 16: wood before compression molding, 20: metal plate as a compressible deformable plate material, 2
Reference numeral 1 denotes a mold, 22 denotes a convex line, and 23 denotes a concave line.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2B230 AA16 AA22 BA01 BA03 EA19 EA20 EB05 EB06 EB11 EB12 EB13 EB24 EB29 EC02 EC24 2B250 AA06 BA03 BA05 CA11 FA18 FA21 FA37 FA53 FA55 GA03 HA01 HA03

Claims (5)

[Claims] 1. Compressed wood formed such that the direction in which the uneven portion on the surface of the wood formed by compression molding extends intersects the direction in which the grain of the wood extends. 2. The compressed wood according to claim 1, wherein the uneven shape of the uneven portion is a smooth corrugated shape. 3. The wood is steamed and softened, the wood is compression-molded by interposing a compressively deformable plate between the wood and a mold, and the shape is heated by high-temperature steam while maintaining the shape. A method for producing compressed wood that is fixed, cooled and dried. 4. The method according to claim 3, wherein the surface of the mold is formed in an uneven shape, and the wood is compressed by the mold such that the direction in which the unevenness extends and the direction in which the grain of the wood before compression molding extends intersect.
3. The method for producing compressed wood according to item 1. 5. The method according to claim 5, wherein the irregularities on the mold surface are formed in a wave shape.
The method for producing compressed wood according to claim 3 or 4, wherein a smooth corrugated shape is formed on the surface of the compression-molded wood.