JP7429920B2 - Method for producing compacted wood - Google Patents

Description

The present invention relates to a method for producing compacted wood whose surface is hardened by compaction processing.

Cedar is an attractive wood with a warm texture and texture, and its demand as a building material is increasing. However, some people avoid using cedar for floorboards and wallboards because it is soft and easily damaged. In this regard, even if the wood is soft, such as cedar, the surface can be painted with urethane paint to make it less susceptible to scratches. However, when painted, the texture and texture of solid wood is lost.

By the way, as a technique for hardening wood, "consolidation processing" is known, in which wood is compressed by applying pressure while heating it (see, for example, Patent Document 1). This consolidation process is carried out in a state where the wood is moistened to make it easier to deform. By performing consolidation processing, it is also possible to harden the wood without damaging the wood's original texture and texture.

However, in consolidation processing,
[1] Moisture trapped in the wood expands due to heating, which may cause cracks or bulging pressure to occur in the wood when it is decompressed.
[2] Difficult to use on wood with locally hard parts (knots).
There was a drawback.

In view of this situation, as shown in FIG. 1 of Patent Document 2, wood 5 is placed on a metal plate 4 with holes, and water vapor is pumped through the holes in the metal plate while the wood 5 is heated. A method of compressing the data has also been proposed. It is said that this not only prevents the wood from cracking, but also makes it possible to process wood with knots (see paragraphs 0013 to 0014 of the same document).

Japanese Unexamined Patent Publication No. 7-80804 Japanese Patent Application Publication No. 2006-116843

However, the method of Patent Document 2 has
[1] In order to compress the knots that are originally hard, it is necessary to contain a large amount of moisture in a wide range of the wood 5. For this reason, compressive deformation occurs in substantially the entire wood 5 (all layers) in the thickness direction, resulting in poor yield.
[2] Since no pressure is applied to the portion of the wood 5 that overlaps with the hole in the metal plate 4, the surface of that portion is not hardened. As a result, areas that are easily scratched remain on the surface of the wood after processing.
[3] On the side of the wood 5 that was in contact with the metal plate 4, a geometric uneven pattern that is an inversion of the unevenness of the metal plate 4 is formed. Therefore, the natural texture and texture of the wood 5 is impaired.
There was a drawback.

The present invention has been made to solve the above problems, and it is not only possible to suppress cracking of wood and process wood with knots, but also to process almost the entire surface of wood in a limited amount. The purpose of the present invention is to provide a method for producing compacted wood that can be efficiently compacted and hardened with moisture. Another object of the present invention is to harden wood without damaging the texture and texture that wood originally has.

The above issues are
Lay the toweling on the top of the lower press board,
Place the wood to be processed on top of the toweling,
Let the moisture contained in the towel cloth soak into the surface layer of the lower surface of the wood,
By pressing the upper press plate against the upper side of the wood while heating the lower press plate to compress the wood,
The problem is solved by providing a method for manufacturing compacted wood, which comprises compacting and hardening the lower surface of the wood.

By the way, the term ``toweling fabric'' is defined in a narrow sense as ``a woven fabric consisting of weft and warp yarns, in which when weaving the weft yarns, some of the warp yarns (pile yarns) are loosened to form loop-shaped parts in the fabric. means ``dough (pile fabric)''. However, in this specification, the term "terry cloth" is used as a general term for thick fabrics having a fluffy surface, and is not limited to towel cloth in the narrow sense. "Toweling" also includes shirred fabrics and brushed fabrics (blankets, etc.).

In this way, when the moisture contained in the terry cloth soaks into the surface layer on the bottom side of the wood and the wood is compressed while heating the bottom side of the wood, only the surface layer on the bottom side of the wood will selectively compress. It is consolidated (surface consolidation). In other words, the area other than the surface layer on the lower side of the wood is hardly consolidated. Therefore, not only can the yield be improved, but also the lower surface of the wood can be efficiently compacted and hardened using a limited amount of moisture.

Furthermore, even if moisture is infiltrated only into the surface layer on the bottom side of the wood, when the wood is heated and compressed, the moisture (which is heated and becomes water vapor during the consolidation process) is trapped. If this happens, there is a risk that the wood will crack or bulge when the pressure is released. In this regard, as in the present invention, by laying a toweling fabric on the underside of the wood, even during consolidation processing, the moisture (steam) retained on the underside of the wood can escape to the outside through the toweling fabric. Therefore, it is also possible to prevent cracking and swelling of the wood.

Furthermore, it becomes possible to perform consolidation processing on knotty wood. This is because when wood with knots is compressed using the method of the present invention, the towel fabric is strongly pressed by the knots and becomes thinner in the areas where the knots overlap, but in the surrounding areas (the areas that do not overlap with the knots), the towel fabric overlaps with the knots. It does not become as thin as the other parts, but rather pushes up the soft parts of the wood (the parts that do not overlap the knots). Therefore, it is possible to leave the knotted parts (originally hard parts) as they are, and selectively consolidate and harden only the knotless parts (originally soft parts).

Furthermore, when wood is compacted by the method of the present invention, knots remain as convex portions on the surface of the wood (compacted wood). For this reason, it is possible to enhance the added value of wood by emphasizing its natural texture and texture, such as with wood that has been subjected to a floating process (a process that emphasizes the unevenness of the wood grain by cutting only the soft parts of the wood). It becomes possible.

In the method for producing compacted wood of the present invention, it is also preferable to sandwich a release fabric having a smoother surface than the toweling between the wood and the toweling. This is because, as mentioned above, toweling has loops and naps on its surface. For this reason, if the wood to be processed is compressed while being placed directly on top of the terry cloth, there is a risk that the terry cloth will stick to the underside of the wood (compacted wood). In this respect, by sandwiching a release fabric that has a smoother surface than terry cloth between the wood and terry cloth, it is possible to prevent the terry cloth from sticking to the underside of the wood (compacted wood). .

In the method for producing compacted wood of the present invention, it is preferable that the toweling material placed under the wood to be processed has a certain thickness. This is because the moisture contained in the wood easily escapes during consolidation. However, if the terry cloth is made too thick, it will be difficult for pressure to be transmitted from the lower press plate to the wood, and there is a risk that it will be difficult to compact the wood to the desired level. For this reason, it is not good to make towel fabric too thick.

Here, it is difficult to measure the thickness of toweling in an objective manner because it easily changes depending on the pressure applied to it. In this regard, the areal density of the toweling fabric (weight per unit area of the toweling fabric) can be easily measured, and the thickness of the toweling fabric is approximately proportional to the areal density of the toweling fabric. Therefore, in this specification, the thickness of the toweling fabric will be expressed by the areal density of the toweling fabric. The areal density (value when the towel is dry; when multiple sheets of toweling are layered, the total value; the same applies hereinafter) of toweling that meets the above requirements is approximately 0.02 to 2 g/cm. It is ² .

In the method for producing compacted wood of the present invention, there are no particular limitations on the timing of heating the lower press plate to a target temperature and the timing of adding moisture to the toweling fabric. However, if you do this in the following order: [1] lay a moist toweling cloth on top of the lower press plate, and then [2] heat the lower press plate to the target temperature, the lower press plate will heat up. The moisture in the terry cloth will evaporate during the process, and the amount of moisture contained in the terry cloth will vary when the wood is placed on it. This makes it difficult to control the softening depth (depth at which moisture is absorbed) in the wood. Therefore, it is preferable to carry out the following steps: [1] preheating the lower press plate to a target temperature, [2] laying toweling on the upper side of the lower press plate, and [3] impregnating the toweling with moisture.

In the method for producing compacted wood of the present invention, the temperature of the lower press plate is not particularly limited as long as compaction processing is possible. It is also possible to heat only the lower press plate and not the upper press plate. However, if there is a large temperature difference between the lower press plate and the upper press plate, a temperature gradient will occur in the thickness direction of the wood being compressed, and the wood after consolidation (consolidated wood) will be prone to deformation such as warping. Become. For this reason, it is preferable to heat not only the lower press plate but also the upper press plate and maintain the upper press plate at approximately the same temperature as the lower press plate.

In the method for manufacturing consolidated wood of the present invention, the temperature of the lower press plate and the temperature of the upper press plate may be changed over time. However, in this case, in addition to complicating temperature control, when processing one piece of wood and starting processing the next piece of wood, the lower press plate and upper press plate must be kept at a predetermined temperature. There is a risk that the cycle time of the consolidation process will become longer, as it will be necessary to wait until the For this reason, it is preferable to keep the temperatures of the lower press plate and the upper press plate substantially constant from the start to the end of compression.

As described above, the present invention not only makes it possible to suppress cracks in wood and process wood with knots, but also to efficiently consolidate almost the entire wood surface with a limited amount of moisture. It becomes possible to provide a method for producing consolidated wood that can be cured. Furthermore, it becomes possible to harden wood without impairing the texture and texture that wood originally has.

FIG. 2 is a cross-sectional view showing a state before compressing the wood in the method for producing compacted wood of the present invention. FIG. 2 is a cross-sectional view showing a state in which wood is being compressed in the method for producing compacted wood of the present invention. FIG. 1 is a cross-sectional view showing a compacted wood obtained by the method for producing compacted wood of the present invention.

0. Outline of the method for manufacturing consolidated wood according to the present invention The method for manufacturing consolidated wood according to the present invention is for manufacturing consolidated wood whose surface has been hardened by consolidation processing. Consolidation processing includes full-thickness consolidation, in which all layers of wood are consolidated, and surface consolidation, in which only the surface layer of wood is consolidated. Of these, the method for producing consolidated wood of the present invention corresponds to surface consolidation.

FIG. 1 is a cross-sectional view showing a state before compressing the wood 50 in the method for manufacturing compacted wood of the present invention. FIG. 2 is a cross-sectional view showing a state in which wood is compressed in the method for producing compacted wood according to the present invention. In the method for manufacturing consolidated wood according to the present invention, as shown in FIGS. 1 and 2, a wood 50 is consolidated using a press device equipped with a lower press plate 10 and an upper press plate 20. Specifically, the following steps [1] to [8] are performed.
[1] Heat the lower press plate 10 and raise the temperature of the lower press plate 10 until it reaches a target temperature. (Lower press plate temperature raising process)
[2] Lay the toweling 30 on the upper surface of the lower press plate 10. (Toweling process)
[3] Lay the release fabric 40 on top of the toweling fabric 30. (Peeling fabric laying process)
[4] Add water to the toweling fabric 30. (hydration process)
[5] Place the wood 50 to be processed on top of the release fabric 40. (Wood placement process)
[6] After completing the wood mounting process in [5] above, leave the wood for a while to steam the surface layer of the lower surface of the wood 50 with the moisture of the toweling cloth 30. (Steaming process)
[7] Lower the upper press plate 20 and press it against the upper side of the wood 50 to compress the wood 50. (compression process)
[8] Raise the upper press plate 20 and take out the consolidated wood 50 (compacted wood). (Wood extraction process)

In the steaming process of [6] above, the water held in the toweling cloth 30 is evaporated by the heat of the lower press plate 10 and becomes water vapor, and the water vapor selectively steams only the surface layer of the lower surface of the wood 50. You will be forced to do so. As a result, only the surface layer on the lower surface side of the wood 50 is easily deformed, so that only the surface layer on the lower surface side of the wood 50 is consolidated in the compression process of [7] above. In other words, the portion other than the surface layer on the lower surface side of the wood 50 is hardly consolidated. Therefore, the thickness of the wood 50 does not change significantly before and after being compressed. Therefore, yield can be improved. In addition, the lower surface side of the wood 50 can be efficiently compacted and hardened with a limited amount of moisture.

In addition, in the toweling fabric laying process of [2] above, by laying the toweling fabric 30 on the upper side of the lower press plate 10, the moisture that was retained on the lower surface side of the wood 50 (it is heated and becomes water vapor during the consolidation process). can be released as shown by arrow A in FIG. 2 when performing the compression step in [7] above. Therefore, moisture that causes cracks and turgor in the wood 50 can be released.

Furthermore, in the toweling fabric laying process of [2] above, by laying the toweling fabric 30 on the upper side of the lower press plate 10, when performing the compression process of above [7], the toweling fabric 30 overlaps the joints 51. Although it is strongly pressed by the knots 51 and becomes thinner, the parts overlapping the non-knots 52 are not as thin as the parts overlapping the knots 51, and the non-knots 52 are pushed up. Therefore, only the non-knot portion 52 is selectively consolidated. Therefore, it is possible to perform consolidation processing on the wood 50 having the knots 51.

FIG. 3 is a sectional view showing a compacted wood 50a obtained by the method for producing compacted wood of the present invention. The compacted wood 50a shown in FIG. 3 is upside down from the compacted wood 50a (wood 50) shown in FIG. As shown in FIG. 3, this consolidated wood 50a has a consolidated layer 52a (portion shown by diagonal hatching with narrow intervals) formed on the surface layer of the non-knot portion 52. The consolidated layer 52a is a portion obtained by compressing and hardening the surface layer portion of the non-knot portion 52, which is originally soft. For this reason, it is hard to get scratched. Since the compacted layer 52a is not painted or the like, the compacted wood 50a retains the natural texture of solid wood.

Layers other than the consolidated layer 52a (layers other than the surface layer) in the non-knot portion 52 are non-consolidated layers 52b (portions indicated by diagonal hatching with wide intervals). This unconsolidated layer 52b is hardly compressed and maintains approximately the original thickness. Therefore, the consolidated wood 50a not only has a high yield, but also is efficiently consolidated with a limited amount of moisture. In addition, no cracks or turgor occur in the consolidated wood 50a. This is because, as described above, when performing the compression step in [7] above, the moisture held on the lower surface side of the wood 50 was released through the towel fabric 30 (FIG. 2).

Furthermore, the consolidated wood 50a is hardly compressed at the knots 51, which were originally hard. Therefore, on the surface of the wood 50 on which the consolidated layer 52a is formed, the knots 51 appear in a convex shape. Therefore, the compacted wood 50a, like wood subjected to floating processing, emphasizes the natural texture and feel of the wood, and has increased added value.

Each of the steps [1] to [8] above will be explained in detail below.

1. Lower Press Plate Temperature Raising Step The lower press plate temperature raising step in [1] above is a step of heating the lower press plate 10 and raising the temperature until it reaches a target temperature (referred to as T ₁ ). . By raising the temperature of the lower press plate 10 to the target temperature _T1 in advance before setting the wood 50 to be processed in the press device, the steaming process in [6] above can be started. Conditions can be made uniform. For this reason, it becomes easier to control the softening depth (depth into which water permeates) of the wood 50 in the steaming process.

This lower press plate temperature raising step may be performed after the wood mounting step in [5] above. However, if the lower press plate temperature raising process is performed after setting the wood 50 to be processed, the amount of moisture contained in the wood 50 at the time of starting the steaming process may vary. The conditions at this time become non-uniform, making it difficult to control the softening depth (the depth at which moisture permeates) of the wood 50 during the steaming process. This is because water also moves from the toweling fabric 30 to the wood 50 during the lower press plate temperature raising process, and how much water moves to the wood 50 during this lower press plate temperature raising process? This is because it is difficult to read what is being done. For this reason, it is preferable to perform the lower press plate temperature raising step before the wood mounting step.

In the method for manufacturing consolidated wood according to the present embodiment, the target temperature _T1 in the lower press plate heating step is equal to the temperature at which the steaming step and the compression process are started. Therefore, the temperature _T1 is set within a range that allows moisture to be vaporized and does not damage the toweling fabric 30 or the wood 50. Specifically, the temperature _T1 is set in the range of 100 to 200°C. The temperature T ₁ of the lower press plate 10 is preferably 160 to 190°C.

By the way, in the method for manufacturing consolidated wood according to the present embodiment, when performing this lower press plate temperature raising step, an upper press plate temperature raising step of raising the temperature of the upper press plate 20 is also performed at the same time. This makes it possible to prevent a temperature gradient from occurring in the thickness direction of the wood 50 during the compression step of [7] above, thereby preventing the wood 50 from cracking or the like. When performing the upper press plate temperature raising step, it is preferable that the target temperature (referred to as T ₂ ) for raising the temperature of the upper press plate 20 is set approximately equal to the target temperature T ₁ of the lower press plate 10. . Although the upper press plate temperature raising process does not have to be performed simultaneously with the lower press plate temperature raising process, it is more efficient to perform them simultaneously.

2. Toweling Fabric Laying Process The toweling fabric laying process is a process of laying toweling fabric 30 on the upper surface of the lower press plate 10, as shown in FIG. Examples of the towel fabric 30 include pile fabric, shirred fabric, and raised fabric (blanket, etc.). In the method for producing compacted wood according to this embodiment, a hand towel made of pile fabric is used as the towel fabric 30.

Only one piece of toweling 30 may be laid on the upper side of the lower press plate 10. However, if there is only one toweling cloth 30, the layer formed by the toweling cloth 30 becomes thinner in the compression process of [7] above, and the moisture (steam) retained in the surface layer on the lower surface side of the wood 50 is transferred to the toweling cloth 30. It becomes difficult to escape through For this reason, it is preferable to lay two or more sheets of terry cloth 30 on the upper side of the lower press plate 10. It is more preferable to lay three or more sheets of toweling 30 on the upper side of the lower press plate 10, and it is still more preferable to lay four or more sheets of towel cloth 30.

However, if the number of toweling fabrics 30 placed on the upper side of the lower press plate 10 is too large, the layer formed of the toweling fabrics 30 will become too thick. For this reason, it becomes difficult for pressure to be transmitted to the non-knot part 52, and there is a possibility that it becomes difficult to selectively consolidate the non-knot part 52. Therefore, it is preferable that the number of toweling fabrics 30 placed on the upper side of the lower press plate 10 is 30 or less. The number of toweling fabrics 30 laid on the upper side of the lower press plate 10 is more preferably 20 or less, and even more preferably 15 or less. In the method for manufacturing compacted wood according to this embodiment, ten sheets of terry cloth 30 are laid on the upper side of the lower press plate 10. However, in FIGS. 1 and 2, only five toweling fabrics 30 are depicted for convenience of illustration.

It is not preferable to make the towel fabric 30 too thin or too thick. The thickness of the towel fabric 30 has a preferable range. In this regard, as mentioned above, in this specification, the thickness of the toweling fabric 30 is defined as the areal density of the toweling fabric 30 (the value when the toweling fabric 30 is dry. When laminating a plurality of toweling fabrics 30, , the total value (the same applies hereinafter). In order to prevent the toweling fabric 30 from becoming too thin, the areal density of the toweling fabric 30 is preferably 0.02 g/cm ² or more. The areal density of the towel fabric 30 is more preferably 0.05 g/cm ² or more, and even more preferably 0.09 g/cm ² or more.

On the other hand, in order to prevent the toweling fabric 30 from becoming too thick, it is preferable that the areal density of the toweling fabric 30 be 2 g/cm ² or less. The areal density of the towel fabric 30 is more preferably 1.5 g/cm ² or less, more preferably 1 g/cm ² or less. In the method for producing compacted wood according to this embodiment, ten sheets of toweling fabric 30 each having an areal density of 0.05 g/cm ² are laminated, thereby increasing the overall areal density of the toweling fabric 30 to 0.5 g/cm 2 . ^cm2 .

The area of the towel cloth 30 is usually made larger than the area of the wood 50. If the towel fabric 30 is smaller than the wood 50, the wood 50 will protrude from the towel fabric 30, making it impossible to consolidate the entire surface layer on the lower surface side of the wood 50 in the compression step of [7] above. .

3. Peeling fabric laying process The peeling fabric laying process is a process of laying the peeling fabric 40 on the upper side of the toweling fabric 30, as shown in FIG. As mentioned above, the toweling fabric 30 is made of pile fabric with loops on the surface, a blanket with raised surface, etc., so when the wood 50 to be processed is placed directly on the top of the toweling fabric 30 and compressed, the toweling fabric is formed. 30 may stick to the lower surface of the wood 50. In this regard, by sandwiching the release fabric 40 between the toweling fabric 30 and the wood 50, the toweling fabric 30 is prevented from sticking to the compressed wood 50 in the compression step of [7] above.

This release fabric 40 has a smoother surface than the toweling fabric 30. In addition, in order to allow moisture seeping into the surface layer of the wood 50 to escape through the toweling fabric 30, the release fabric 40 is made of water permeable material. Examples of such fabrics include fabrics (such as plain weave fabrics and twill weave fabrics) that do not have pile portions or raised portions on the surface. In the method for producing compacted wood according to this embodiment, gauze (a cloth made of coarsely woven cotton thread) is used as the release fabric 40. Although a plurality of pieces of release fabric 40 may be stacked, one piece is usually sufficient.

4. Water Addition Process The water addition process is a process for causing the toweling fabric 30 to retain moisture. The moisture retained in the toweling fabric 30 in this water addition process is converted into water vapor in the steaming process in [6] above, and is used to soften (soften) the surface layer on the lower surface side of the wood 50. This water addition step may be performed before the towel base setting step in [2] above. However, in the method for manufacturing consolidated wood according to the present embodiment, the lower press plate temperature raising step is performed first, but if water is added to the towel fabric 30 before being spread on the upper side of the lower press plate 10, Immediately after the toweling fabric 30 is laid on the lower press plate 10, the moisture in the toweling fabric 30 begins to evaporate. For this reason, it becomes difficult to control the softening depth of the wood 50 in the steaming step of [6] above. Therefore, it is preferable that the water addition step be performed before the steaming step and at a timing as close as possible to the steaming step. In the method for producing compacted wood according to this embodiment, the water addition step is performed immediately before the wood mounting step.

The amount of water retained in the towel cloth 30 is neither too small nor too large. This is because if the amount of water retained in the toweling fabric 30 is too small, water cannot be sufficiently soaked into the surface layer of the wood 50, making it difficult to compact the surface layer of the wood 50. For this reason, it is preferable that the amount of water (value per unit area of wood 50; the same applies hereinafter) held by the towel cloth 30 be 0.05 mL/cm ² or more. The amount of water retained in the towel cloth 30 is more preferably 0.1 mL/cm ² or more, and even more preferably 0.2 mL/cm ² or more.

On the other hand, if the amount of water held in the towel cloth 30 is too large, the water will seep into a wide area other than the surface layer of the wood 50, making it difficult to selectively consolidate only the surface layer of the wood 50. For this reason, it is preferable that the amount of water held in the towel cloth 30 is 2 mL/cm ² or less. The amount of water retained in the toweling cloth 30 is more preferably 1 mL/cm ² or less, and even more preferably 0.5 mL/cm ² or less. In the method for producing compacted wood according to the present embodiment, the amount of water held in the towel cloth 30 is 0.4 mL/cm ² .

5. Wood Placing Process The wood placement process is a process of placing wood 50 on the upper side of the peeling fabric 40 (on the toweling fabric 30), as shown in FIG. The wood 50 is placed with the surface to be consolidated facing downward (releasing fabric 40 side). The amount of moisture supplied to the wood 50 in the steaming process of [6] above is controlled by placing the wood 50 on the lower press plate 10 in [1] above after raising the temperature to the target temperature _T1 . This makes it easier to keep the softening depth (the depth at which water penetrates) within the desired range.

By the way, the wood 50 contains a certain amount of moisture even before the water addition step in [4] above is performed. In this regard, if the wood 50 with an original high moisture content is placed in this wood mounting process, the entire wood 50 (all layers) will be deformed in the compression process of [7] above, and the wood 50 will be deformed in the compression process of [7] above. It becomes difficult to selectively compress only the surface layer. For this reason, it is preferable that the wood 50 placed in the wood placement step has a low moisture content. Specifically, the moisture content of the wood 50 (the moisture content before performing the water addition step; the same applies hereinafter) is preferably 30% or less, more preferably 20% or less. In the method for manufacturing compacted wood according to this embodiment, the wood 50 is air-dried before being placed on the towel cloth 30 to reduce its moisture content to 15% or less.

6. Steaming process The steaming process is a process in which the wood 50 is left for a while after the wood mounting process in [5] above is completed, and the surface layer of the lower surface of the wood 50 is steamed with the moisture of the toweling fabric 30. Thereby, only the surface layer portion on the lower surface side of the wood 50 (particularly the surface layer portion of the non-knot portion 52) can be softened and softened, making it easy to compress and deform. In the method for manufacturing consolidated wood of this embodiment, the lower press plate 10 and the upper press plate 20 are heated in the lower press plate temperature raising step (and upper press plate temperature raising step) of [1] above. The steaming process is performed while maintaining the temperatures T ₁ and T ₂ . The steaming step is usually carried out for 5 to 30 minutes, preferably 10 to 15 minutes.

7. Compression Step As shown in FIG. 2, the compression step is a step in which the upper press plate 20 is lowered and pressed against the upper side of the wood 50, and the surface layer of the lower surface of the wood 50 is compressed while being heated. As a result, the surface layer on the lower surface side of the wood 50 is consolidated. In the method for manufacturing consolidated wood of this embodiment, the lower press plate 10 and the upper press plate 20 are heated in the lower press plate temperature raising step (and upper press plate temperature raising step) of [1] above. The compression process is started while maintaining the temperatures T ₁ and T ₂ .

The pressure applied to the wood 50 in the compression process varies depending on the type of wood 50 and the use of the resulting compacted wood 50a, and is not particularly limited. However, if the pressure applied to the wood 50 is too small, the surface layer of the wood 50 may not be sufficiently compacted. Therefore, the pressure applied to the wood 50 is preferably 1 kgf/cm ² or more. The pressure applied to the wood 50 is more preferably 3 kgf/cm ² or more, and even more preferably 5 kgf/cm ² or more.

On the other hand, if the pressure applied to the wood 50 is too large, there is a risk that the wood 50 will be damaged, such as cracking. Therefore, the pressure applied to the wood 50 is preferably 30 kgf/cm ² or less. The pressure applied to the wood 50 is more preferably 20 kgf/cm ² or less, and even more preferably 15 kgf/cm ² or less. In the method for producing compacted wood according to this embodiment, the pressure applied to the wood 50 in the compression step is 10 kgf/cm ² . The time for performing the compression step is not particularly limited, but is usually 30 to 150 minutes, preferably 100 to 120 minutes.

While performing this compression process, the temperature of the lower press plate 10 and the upper press plate 20 may be changed over time, but in this case, complicated temperature control is required, and the There is also a possibility that the cycle time for manufacturing the wood 50a becomes longer. Therefore, in the method for producing compacted wood according to the present embodiment, the temperatures of the lower press plate 10 and the upper press plate 20 are kept substantially constant from the start to the end of the compression process.

By the way, in the method for manufacturing consolidated wood according to this embodiment, as shown in FIG. 1, a spacer 60 is provided between the lower press plate 10 and the upper press plate 20. Without this spacer 60, the upper press plate 20 would descend too much with respect to the lower press plate 10, and the thickness of the resulting consolidated wood 50a might be smaller than the target value. By installing the upper press plate 20, it is possible to prevent the upper press plate 20 from lowering below a predetermined position and to make the thickness of the obtained consolidated wood 50a match the target value.

8. Wood Removal Process The wood removal process is a process in which the upper press plate 20 is raised and the consolidated wood 50 (compacted wood 50a in FIG. 3) is taken out. Since the release fabric 40 is placed between the wood 50 and the toweling fabric 30 in the step of laying the separation fabric in [3] above, the toweling fabric 30 can be easily peeled off from the compacted wood 50a. When the wood extraction step is completed, a series of steps in the method for manufacturing compacted wood of the present invention is completed.

In the method for manufacturing consolidated wood of the present invention, moisture (steam) that causes cracks and bulge in the wood 50 escapes through the toweling fabric 30 in the compression step of [7] above. Even if the upper press plate 20 is raised immediately after the compression process is finished, the wood 50 will not crack or bulge. Therefore, the wood 50 can be taken out immediately after the compression step in [7] above is completed.

By the way, as shown in FIG. 3, the removed compacted wood 50a has knots 51 remaining in a convex shape on the surface on the compacted layer 52a side. The convexly protruding portions of the knots 51 can emphasize the natural texture and texture of the wood. However, depending on the use of the consolidated wood 50a, it may not be preferable for the knots 51 to have a convex shape. In such a case, the convexly protruding portions of the knots 51 may be removed by polishing the surface layer of the consolidated wood 50a. The compacted wood 50a has sufficient hardness even if its surface layer is shaved off by about 0.2 to 0.5 mm.

9. Manufacture of the next consolidated wood If another piece of wood 50 is to be subsequently consolidated, the steps [1] to [8] above may be performed again. In the method for manufacturing consolidated wood of this embodiment, as described above, the temperatures of the lower press plate 10 and the upper press plate 20 are kept approximately constant from the start to the end of the compression process in [7] above. As a result, the consolidation process of the next piece of wood 50 can be started immediately after the wood removal process in [8] above is completed. When performing the compression process, there is a risk that oil seeping from the joints 51 may soak into the toweling fabric 30 and the release fabric 40, but if the toweling fabric 30 and the release fabric 40 are contaminated with oil or the like, It is preferable to replace the toweling fabric 30 and the release fabric 40. The dirty towel cloth 30 and release cloth 40 can be washed and reused.

10. Applications The method for producing compacted wood of the present invention can be used to compact various types of wood. In the method for producing compacted wood of the present invention, softwood, hardwood, or the like can be cured to become compacted wood. In particular, many softwood materials such as cedar and pine are soft and easily damaged. For this reason, when coniferous wood is used as a raw material, the significance of employing the method for producing compacted wood of the present invention is particularly increased. The compacted wood obtained by the method for producing compacted wood of the present invention can be suitably used as building materials such as floorboards and wallboards, furniture materials such as chests of drawers and chairs, and the like.

10 Lower press plate 20 Upper press plate 30 Towel cloth 40 Release fabric 50 Wood 50a Consolidated wood 51 Knots 52 Non-knots 52a Consolidated layer 52b Non-consolidated layer 60 Spacer

Claims (5)

Lay the toweling on the top of the lower press board,
Lay a release fabric with a smoother surface than the toweling on top of the toweling,
Place the wood to be processed on top of the stripping fabric ,
Let the moisture contained in the towel cloth soak into the surface layer of the lower surface of the wood,
By pressing the upper press plate against the upper side of the wood while heating the lower press plate to compress the wood,
A method for producing compacted wood, comprising compacting and hardening the lower surface of the wood.
Place toweling on top of the lower press plate, which has been preheated to the target temperature .
After soaking the towel cloth with water,
Place the wood to be processed on top of the toweling,
Let the moisture contained in the towel cloth soak into the surface layer of the lower surface of the wood,
By pressing the upper press plate against the upper side of the wood while heating the lower press plate to compress the wood,
A method for producing compacted wood, comprising compacting and hardening the lower surface of the wood.
The method for producing compacted wood according to claim 1 or 2, wherein the towel fabric has an areal density of 0.02 g/cm ² to 2 g/cm ² .
4. The method for producing compacted wood according to claim 1, wherein the upper press plate is maintained at approximately the same temperature as the lower press plate.
5. The method for producing compacted wood according to claim 4 , wherein the temperatures of the upper press plate and the lower press plate are kept substantially constant from the start to the end of compression of the wood.

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