JP2021133518A - Manufacturing method of consolidated wood - Google Patents

Abstract

To provide a manufacturing method of consolidated wood which cannot only suppress cracking of wood or can process knotted wood, without damaging texture or feeling which wood intrinsically has, but also can harden by efficiently consolidating substantially entirety in a wood surface with limited amount of water.SOLUTION: The towel cloth 30 is laid on the upper side of the lower press plate 10, and the wood 50 as the work piece is placed on the upper side of the towel cloth 30, and the water contained in the towel cloth 30 is soaked in the surface layer of the lower surface of the wood 50. By pressing the upper press plate 20 on the upper side of the wood 50 to compress the wood 50 while heating the lower press plate 10 to consolidate the lower side of the wood 50 to harden. It is better that after laying the towel cloth 30 on the upper side of the lower press plate 10 heated up to a target temperature, it is preferable that water content is contained in the towel cloth 30.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for producing a consolidated wood whose surface has been hardened by consolidation processing.

Sugi is a wood with an attractive warm texture and texture, and its demand as a building material is increasing. However, because sugi is soft and easily damaged, some people avoid using it for floorboards and wallboards. In this respect, even soft wood such as sugi can be made less likely to be scratched by painting the surface with urethane paint or the like. However, when painted, the texture and texture of solid wood is impaired.

By the way, as a technique for hardening wood, "consolidation processing" in which wood is compressed by pressurizing while heating is known (see, for example, Patent Document 1). This consolidation process is performed in a state where the wood is moistened to make it easy to deform. When the consolidation process is performed, it is possible to harden the wood without impairing the texture and texture originally possessed by the wood.

However, for consolidation processing,
[1] Moisture trapped in wood expands due to heating, which may cause cracks or turgor pressure in the wood at the time of decompression.
[2] It is difficult to use for wood with locally hard parts (knots).
There was a drawback.

In view of such an actual situation, so far, as shown in FIG. 1 of Patent Document 2, the wood 5 is placed on the metal plate 4 having a hole, and the wood 5 is sent water vapor from the hole of the metal plate. A method of compressing is also 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 Unexamined Patent Publication No. 2006-116843

However, in the method of Patent Document 2,
[1] Since the originally hard knot portion is also compressed, it is necessary to include a large amount of water in a wide range of the wood 5. For this reason, compression deformation occurs in substantially the entire surface (all layers) of the wood 5 in the plate thickness direction, resulting in poor yield.
[2] Since no pressure is applied to the portion of the wood 5 that overlaps the hole of the metal plate 4, the surface of that portion is not hardened. For this reason, a portion that is easily scratched remains on the surface of the processed wood.
[3] On the surface of the wood 5 that is in contact with the metal plate 4, a geometric uneven pattern is formed by reversing the unevenness of the metal plate 4. 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 possible not only to suppress cracking of wood and to process wood with knots, but also to process substantially the entire surface of the wood in a limited amount. It provides a method for producing a compacted wood that can be efficiently compacted and hardened with the moisture of the above. It is also an object of the present invention to harden the wood without impairing the texture and texture originally possessed by the wood.

The above issues are
Place the towel cloth on the upper side of the lower press plate,
Place the wood to be processed on the upper side of the towel cloth and place it.
Moisture contained in the towel cloth is impregnated into the surface layer on the lower surface side 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 solution is to provide a method for producing a consolidated wood, which comprises compacting and hardening the lower surface side of the wood.

By the way, the word "towel cloth" is narrowly defined as "a woven fabric consisting of weft threads and warp threads, and when weaving the weft threads, a part of the warp threads (pile threads) is loosened to form a loop-shaped part on the fabric. It means "fabric (pile fabric)". However, in the present specification, the term "towel cloth" is used as a general term for thick cloth having a fluffy surface, and is not limited to towel cloth in a narrow sense. "Towel cloth" also includes shirring cloth and brushed cloth (blanket, etc.).

In this way, when the moisture contained in the towel cloth is impregnated into the surface layer portion on the lower surface side of the wood and the wood is compressed while heating the lower surface side of the wood, only the surface layer portion on the lower surface side of the wood is selectively selected. Consolidation (surface consolidation). In other words, only the surface layer portion on the lower surface side of the wood is in a state of being hardly compacted. Therefore, not only the yield can be improved, but also the lower surface side of the wood can be efficiently compacted and hardened with a limited amount of water.

Further, even when water is impregnated only in the surface layer on the lower surface side of the wood, the water (heated to become water vapor during compaction processing) is trapped when the wood is compressed while being heated. In this state, the wood may crack or turgor when it is decompressed. In this regard, by laying the towel cloth on the lower side of the wood as in the present invention, the moisture (water vapor) retained on the lower surface side of the wood can escape to the outside through the towel cloth even during the consolidation process. Therefore, it is possible to prevent the wood from cracking and turgor pressure.

Furthermore, it becomes possible to perform consolidation processing on knotted wood. This is because when the wood with knots is compressed by the method of the present invention, the towel cloth is strongly pressed by the knots at the part where it overlaps with the knots and becomes thin, but it overlaps with the knots around it (the part where it does not overlap with the knots). It is not as thin as the part and pushes up the soft part of the wood (the part that does not overlap the knots). Therefore, it is possible to leave the knotted portion (originally hard portion) as it is and selectively consolidate and harden only the knotless portion (originally soft portion).

Furthermore, when the wood is compacted by the method of the present invention, the knot portion remains as a convex portion on the surface of the wood (consolidated wood). For this reason, it is possible to increase the added value of wood by emphasizing the natural texture and texture, such as wood that has undergone floating processing (processing that emphasizes the unevenness of the wood grain by scraping only the soft part of the wood). It will be possible.

In the method for producing compacted wood of the present invention, it is also preferable to sandwich a peeling cloth having a smoother surface than the towel cloth between the wood and the towel cloth. This is because, as mentioned above, the towel cloth has loops and brushes on its surface. Therefore, if the wood to be processed is compressed while being directly placed on the upper side of the towel cloth, the towel cloth may stick to the lower surface of the wood (consolidated wood). In this respect, by sandwiching the peeling cloth having a smoother surface than the towel cloth between the wood and the towel cloth, it is possible to prevent the towel cloth from sticking to the lower surface of the wood (consolidated wood). ..

In the method for producing compacted wood of the present invention, it is preferable that the towel cloth laid under the wood to be processed has a certain thickness. This is because the moisture contained in the wood easily escapes during the consolidation process. However, if the towel cloth is made too thick, pressure may not be easily transmitted from the lower press plate to the wood, and it may be difficult to consolidate the wood to a desired level. For this reason, it is not good for the towel cloth to be too thick.

Here, since the thickness of the towel cloth easily changes depending on the pressure applied to it, it is difficult to measure it by an objective method. In this respect, the surface density of the towel cloth (weight per unit area of the towel cloth) can be easily measured, and the thickness of the towel cloth is generally proportional to the surface density of the towel cloth. Therefore, in the present specification, the thickness of the towel cloth is expressed by the surface density of the towel cloth. The surface density of the towel cloth that meets the above requirements (value when the towel is dry. When multiple towel cloths are laminated, the total value. The same shall apply hereinafter) is approximately 0.02 to 2 g / cm. It is ^2.

In the method for producing compacted wood of the present invention, the timing of heating the lower press plate to a target temperature and the timing of moistening the towel cloth are not particularly limited. However, if [1] a towel cloth moistened is laid on the upper side of the lower press plate and then [2] the lower press plate is heated to the target temperature, the lower press plate is heated. Moisture in the towel cloth will evaporate during the process, and the amount of water contained in the towel cloth will vary when the wood is placed. For this reason, it becomes difficult to control the softening depth (depth to contain water) in wood. Therefore, it is preferable that [1] the lower press plate is preheated to a target temperature, [2] a towel cloth is laid on the upper side of the lower press plate, and [3] the towel cloth is moistened.

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 it can be consolidated. It is not necessary to heat only the lower press plate and not the upper press plate. However, if the temperature difference between the lower press plate and the upper press plate is large, a temperature gradient occurs in the thickness direction of the compressed wood, and the wood after consolidation (consolidation wood) is likely to be deformed such as warping. Become. Therefore, it is preferable to heat not only the lower press plate but also the upper press plate to keep the upper press plate at a temperature substantially equal to that of the lower press plate.

In the method for producing compacted 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 the complicated temperature control, when the processing of one wood is finished and the processing of the next wood is started, the lower press plate and the upper press plate have a predetermined temperature. There is a possibility that the cycle time of consolidation processing will be long, such as having to wait until the temperature reaches. Therefore, 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, according to the present invention, it is possible not only to suppress cracking of wood and to process wood with knots, but also to efficiently consolidate almost the entire surface of wood with a limited amount of water. It becomes possible to provide a method for producing a consolidated wood that can be hardened. It also makes it possible to provide hardening of wood without compromising the original texture and texture of the wood.

It is sectional drawing which showed the state before compression of wood in the manufacturing method of consolidation wood of this invention. It is sectional drawing which showed the state which compressed the wood in the manufacturing method of the consolidation wood of this invention. It is sectional drawing which showed the consolidation wood obtained by the manufacturing method of the consolidation wood of this invention.

0. Outline of Method for Producing Consolidated Wood of the Present Invention The method for producing a consolidated wood of the present invention is for producing a consolidated wood whose surface is hardened by compaction processing. There are two types of consolidation processing: full-layer consolidation, which compacts all layers of wood, and surface consolidation, which compacts only the surface layer of wood. Of these, the method for producing compacted wood of the present invention corresponds to surface consolidation.

FIG. 1 is a cross-sectional view showing a state before compression of wood 50 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 compressed in the method for producing compacted wood of the present invention. In the method for producing compacted wood of the present invention, as shown in FIGS. 1 and 2, the wood 50 is compacted using a press device provided with a lower press plate 10 and an upper press plate 20. Specifically, the following steps [1] to [8] are performed.
[1] The lower press plate 10 is heated, and the temperature of the lower press plate 10 is raised until it reaches a target temperature. (Lower press plate heating process)
[2] A towel cloth 30 is laid on the upper surface of the lower press plate 10. (Towel cloth laying process)
[3] Spread the peeling cloth 40 on the upper side of the towel cloth 30. (Dough laying process for peeling)
[4] Add water to the towel cloth 30. (Water addition process)
[5] The wood 50 to be processed is placed on the upper side of the peeling cloth 40. (Wood placement process)
[6] After the wood placing step of the above [5] is completed, the wood is left for a while, and the surface layer portion on the lower surface side of the wood 50 is steamed with the moisture of the towel cloth 30. (Steaming process)
[7] The upper press plate 20 is lowered and pressed against the upper side of the wood 50 to compress the wood 50. (Compression process)
[8] The upper press plate 20 is raised, and the compacted wood 50 (consolidated wood) is taken out. (Wood removal process)

In the steaming step of the above [6], the water retained in the towel cloth 30 is evaporated by the heat of the lower press plate 10 to become steam, and only the surface layer portion on the lower surface side of the wood 50 is selectively steamed by the steam. Will be released. As a result, only the surface layer portion on the lower surface side of the wood 50 is easily deformed, so that only the surface layer portion on the lower surface side of the wood 50 is compacted in the compression step of the above [7]. In other words, the portion of the wood 50 other than the surface layer portion on the lower surface side is hardly consolidated. Therefore, the thickness of the wood 50 does not change significantly before and after being compressed. Therefore, the 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 water.

Further, in the towel cloth laying step of the above [2], by laying the towel cloth 30 on the upper side of the lower press plate 10, the moisture retained on the lower surface side of the wood 50 (heated to become steam during the consolidation process). Can be released as shown by the arrow A in FIG. 2 when the compression step of the above [7] is performed. Therefore, moisture that causes cracks and turgor pressure in the wood 50 can be released.

Further, in the towel cloth laying step of the above [2], the towel cloth 30 is laid on the upper side of the lower press plate 10, so that when the compression step of the above [7] is performed, the towel cloth 30 overlaps the knot 51. Although it is strongly pressed by the knot 51 to become thinner, the portion overlapping the non-knot 52 is not as thin as the portion overlapping the knot 51, and the non-knot 52 is pushed up. Therefore, only the non-knot 52 is selectively consolidated. Therefore, it is possible to perform the consolidation processing on the wood 50 having the knots 51.

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

The layer other than the consolidation layer 52a (layer other than the surface layer portion) in the non-consolidated portion 52 is a non-consolidation layer 52b (a portion indicated by diagonal hatching with a wide interval). The non-consolidated layer 52b is hardly compressed and maintains a substantially original thickness. Therefore, the compacted wood 50a not only has a good yield, but is also efficiently consolidated with a limited amount of water. Further, the compacted wood 50a is not cracked or turgor pressure is generated. This is because, as described above, when the compression step of the above [7] is performed, the moisture retained on the lower surface side of the wood 50 is released through the towel cloth 30 (FIG. 2).

Further, the consolidated wood 50a is hardly compressed at the originally hard knot 51. Therefore, on the surface of the wood 50 on the side where the consolidation layer 52a is formed, the knot portion 51 is in a convex state. Therefore, the compacted wood 50a has an enhanced added value by emphasizing the natural texture and texture of the wood, similar to the wood that has been subjected to the floating process.

Hereinafter, each step of the above [1] to [8] will be described in detail.

1. 1. Lower press ItaNoboru raising step of the lower press ItaNoboru raising step [1] is to heat the lower press plate 10, it is a step of raising the temperature to reach the target temperature (T ₁ to.) .. Before setting the timber 50 to be processed in the press apparatus, by leaving raised to temperature T ₁ of in advance target of the temperature of the lower press plate 10, when starting the steaming step of the [6] The conditions can be made uniform. Therefore, it becomes easy to control the softening depth (depth of moisture permeation) of the wood 50 in the steaming process.

This lower press plate heating step may be performed after the wood placing step of the above [5]. However, if the lower press plate raising step is performed after setting the wood 50 to be processed, the amount of water contained in the wood 50 at the start of the steaming step varies, and the steaming step is started. The conditions at this time become non-uniform, and it becomes difficult to control the softening depth (depth of water permeation) of the wood 50 in the steaming process. This is because the moisture moves from the towel cloth 30 to the wood 50 during the lower press plate raising step, and how much moisture moves to the wood 50 during the lower press plate raising step. This is because it is difficult to read what to do. Therefore, it is preferable that the lower press plate temperature raising step is performed before the wood placing step.

In the method for producing compacted wood of the present embodiment, the target temperature T ₁ 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 T ₁ is set within a range in which the moisture can be vaporized and the towel cloth 30 and the wood 50 are not damaged. Specifically, the temperature T ₁ 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 producing compacted wood of the present embodiment, when the lower press plate raising step is performed, the upper press plate raising step of raising the temperature of the upper press plate 20 is also performed at the same time. As a result, it is possible to prevent the wood 50 from cracking by preventing a temperature gradient in the plate thickness direction from occurring in the wood 50 when the compression step of the above [7] is performed. _{When the upper press plate heating step is performed, it is preferable that the target temperature (T 2} ) for raising the temperature of the upper press plate 20 is set to be substantially equal to _{the target temperature T 1} of the lower press plate 10. .. The upper press plate heating step does not have to be performed at the same time as the lower press plate heating step, but it is more efficient to perform the upper press plate heating step at the same time.

2. Towel cloth laying step As shown in FIG. 1, the towel cloth laying step is a step of laying the towel cloth 30 on the upper surface of the lower press plate 10. Examples of the towel cloth 30 include pile cloth, shirring cloth, and brushed cloth (blanket, etc.). In the method for producing compacted wood of the present embodiment, a hand towel made of pile cloth is used as the towel cloth 30.

Only one towel cloth 30 may be laid on the upper side of the lower press plate 10. However, if there is only one towel cloth 30, the layer formed by the towel cloth 30 becomes thin in the compression step of the above [7], and the moisture (water vapor) retained in the surface layer portion on the lower surface side of the wood 50 becomes the towel cloth 30. It becomes difficult to escape through. Therefore, it is preferable to lay two or more towel cloths 30 on the upper side of the lower press plate 10. It is more preferable to lay three or more towel cloths 30 on the upper side of the lower press plate 10, and it is further preferable to lay four or more towel cloths.

However, if the number of towel cloths 30 laid on the upper side of the lower press plate 10 is too large, the layer formed by the towel cloth 30 becomes too thick. Therefore, it becomes difficult for the pressure to be transmitted to the non-knotted portion 52, and it may be difficult to selectively consolidate the non-knotted portion 52. Therefore, the number of towel cloths 30 laid on the upper side of the lower press plate 10 is preferably 30 or less. The number of towel cloths 30 laid on the upper side of the lower press plate 10 is more preferably 20 or less, and further preferably 15 or less. In the method for producing compacted wood of the present embodiment, 10 towel cloths 30 are laid on the upper side of the lower press plate 10. However, in FIGS. 1 and 2, only five towel cloths 30 are drawn for convenience of illustration.

It is not preferable that the towel cloth 30 is too thin or too thick. There is a preferable range in the thickness of the towel cloth 30. In this regard, in the present specification, as already described, the thickness of the towel cloth 30 is the surface density of the towel cloth 30 (value when the towel cloth 30 is dry. When a plurality of towel cloths 30 are laminated , The total value. The same shall apply hereinafter.) In order to prevent the towel cloth 30 from becoming too thin, the surface density of the towel cloth 30 ^{is preferably 0.02 g / cm 2} or more. The areal density of the toweling 30, more preferably to 0.05 g / cm ² or more, still more preferably 0.09 g / cm ² or more.

On the other hand, in order to prevent the towel cloth 30 from becoming too thick, it is preferable that ^{the surface density of the towel cloth 30 is 2 g / cm 2 or less.} The surface density of the towel cloth 30 ^{is preferably 1.5 g / cm 2} or less, and more preferably 1 g / cm ² or less. In the method for producing compacted wood of the present embodiment, the total surface density of the towel cloth 30 is 0.5 g / ^{cm / cm by laminating 10 towel cloths 30 having a surface density of 0.05 g / cm 2 per sheet.} It is set to cm ² .

The area of the towel cloth 30 is usually larger than the area of the wood 50. This is because if the towel cloth 30 is smaller than the wood 50, the wood 50 protrudes from the towel cloth 30, and in the compression step of the above [7], the entire surface layer portion on the lower surface side of the wood 50 cannot be consolidated. ..

3. 3. Peeling cloth laying step As shown in FIG. 1, the peeling cloth laying step is a step of laying the peeling cloth 40 on the upper side of the towel cloth 30. As described above, the towel cloth 30 uses a pile cloth having a loop on the surface, a blanket having a brushed surface, and the like. Therefore, when the wood 50 to be processed is directly placed on the upper side of the towel cloth 30 and compressed, the towel cloth is compressed. 30 may stick to the lower surface of the wood 50. In this regard, by sandwiching the peeling cloth 40 between the towel cloth 30 and the wood 50, the towel cloth 30 is prevented from sticking to the compressed wood 50 in the compression step of the above [7].

As the peeling cloth 40, a cloth having a smoother surface than the towel cloth 30 is adopted. Further, in order to allow the moisture that has soaked into the surface layer portion of the wood 50 to escape through the towel cloth 30, a material having water permeability is adopted as the peeling cloth 40. Examples of such a fabric include a fabric having no pile portion or raised portion on the surface (plain weave fabric, twill weave fabric, etc.). In the method for producing compacted wood of the present embodiment, gauze (a cloth in which cotton threads are coarsely woven into a plain weave) is used as the peeling cloth 40. A plurality of sheets of the peeling cloth 40 may be stacked, but usually one sheet is sufficient.

4. Watering step The watering step is a step of retaining water in the towel cloth 30. The water retained in the towel cloth 30 in this water addition step becomes steam in the steaming step of the above [6] and is used to soften (soften) the surface layer portion on the lower surface side of the wood 50. This water addition step may be performed before the towel cloth setting step of the above [2]. However, in the method for producing compacted wood of the present embodiment, when the lower press plate heating step is first performed, the towel cloth 30 before being laid on the upper side of the lower press plate 10 is preliminarily hydrated. Immediately after the towel cloth 30 is laid on the lower press plate 10, the water content of the towel cloth 30 begins to evaporate. Therefore, in the steaming step of the above [6], it becomes difficult to control the softening depth of the wood 50. Therefore, it is preferable that the water addition step is performed before the steaming step and at a timing as close as possible to the steaming step. In the method for producing compacted wood of the present embodiment, a water addition step is performed immediately before the wood placing step.

The amount of water retained in the towel cloth 30 may be too small or too large. This is because if the amount of water held in the towel cloth 30 is too small, the surface layer portion of the wood 50 cannot be sufficiently impregnated with water, and it becomes difficult to consolidate the surface layer portion of the wood 50. Therefore, the amount of water held in the towel cloth 30 (value per unit area of the wood 50; the same applies hereinafter) is ^{preferably 0.05 mL / cm 2} or more. The amount of water to be retained in the towel cloth 30 ^{is more preferably 0.1 mL / cm 2} or more, and further 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 permeates into a wide range other than the surface layer portion of the wood 50, and it becomes difficult to selectively consolidate only the surface layer portion of the wood 50. Therefore, the amount of water retained in the towel cloth 30 ^{is preferably 2} mL / cm 2 or less. The amount of water to be retained in the towel cloth 30 ^{is more preferably 1 mL / cm 2} or less, and further preferably 0.5 mL / cm ² or less. In the method for producing compacted wood of the present embodiment, the amount of water held in the towel cloth 30 is 0.4 mL / cm ² .

5. Wood placing step As shown in FIG. 1, the wood placing step is a step of placing the wood 50 on the upper side of the peeling cloth 40 (the upper side of the towel cloth 30). The wood 50 is placed with the surface to be consolidated facing downward (the peeling cloth 40 side). By placing the wood 50 after raising the temperature of the lower press plate 10 of the above [1] to the target temperature T _{1, the} amount of water supplied to the wood 50 in the steaming step of the above [6] is controlled. Since it is easy to do so, it becomes easy to keep the softening depth (depth to soak in water) within the target range.

By the way, the wood 50 contains a certain amount of water even in a stage prior to the water addition step of the above [4]. In this respect, when the wood 50 originally having a high water content is placed in this wood placing step, the entire wood 50 (all layers) is deformed in the compression step of the above [7], and the wood 50 becomes deformed. It becomes difficult to selectively compress only the surface layer portion. Therefore, it is preferable that the wood 50 placed in the wood placing step has a low water content. Specifically, the water content of the wood 50 (the water content before the water addition step; the same applies hereinafter) is preferably 30% or less, and more preferably 20% or less. In the method for producing compacted wood of the present embodiment, the wood 50 is naturally dried before being placed on the upper side of the towel cloth 30, and the water content thereof is reduced to 15% or less.

6. Steaming step The steaming step is a step of leaving the wood 50 for a while while the wood placing step of the above [5] is completed, and steaming the surface layer portion on the lower surface side of the wood 50 with the moisture of the towel cloth 30. As a result, 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 so as to be easily compressed and deformed. In the method for producing compacted wood of the present embodiment, the lower press plate 10 and the upper press plate 20 are heated in the lower press plate raising step (and the upper press plate raising step) of the above [1]. 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 of lowering the upper press plate 20 and pressing it against the upper side of the wood 50 to compress the surface layer portion on the lower surface side of the wood 50 while heating it. As a result, the surface layer portion on the lower surface side of the wood 50 is consolidated. In the method for producing compacted wood of the present embodiment, the lower press plate 10 and the upper press plate 20 are heated in the lower press plate heating step (and the upper press plate heating step) of the above [1]. The compression process is started while keeping the temperatures T ₁ and T _2.

The pressure applied to the wood 50 in the compression step varies depending on the type of the wood 50, the use of the obtained compacted wood 50a, and the like, and is not particularly limited. However, if the pressure applied to the wood 50 is too small, the surface layer portion 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, the wood 50 may be damaged such as cracked. 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 of the present 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.

During this compression step, the temperatures 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 consolidation is performed. There is a possibility that the cycle time for producing the wood 50a will be long. Therefore, in the method for producing compacted wood of 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 step.

By the way, in the method for producing compacted wood of the present 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 may be lowered too much with respect to the lower press plate 10, and the thickness of the obtained compacted wood 50a may be smaller than the target value. However, this spacer 60 By installing the above, the upper press plate 20 can be prevented from lowering below a predetermined position, and the plate thickness of the obtained compacted wood 50a can be matched with the target value.

8. Wood taking-out step The wood taking-out step is a step of raising the upper press plate 20 and taking out the consolidated wood 50 (consolidated wood 50a in FIG. 3). Since the peeling cloth 40 was arranged between the wood 50 and the towel cloth 30 in the peeling cloth laying step of the above [3], the towel cloth 30 can be easily peeled off from the consolidated wood 50a. When the wood removal step is completed, a series of steps in the method for producing compacted wood of the present invention is completed.

In the method for producing compacted wood of the present invention, moisture (water vapor) that causes cracking and turgor pressure of the wood 50 escapes through the towel cloth 30 in the compression step of the above [7]. Even if the upper press plate 20 is raised immediately after the compression step is completed, the wood 50 does not crack or turgor pressure. Therefore, the wood 50 can be taken out immediately after the compression step of the above [7] is completed.

By the way, in the consolidated wood 50a taken out, as shown in FIG. 3, the knots 51 remain convex on the surface on the consolidation layer 52a side. The convexly protruding portion of the knot 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 that the knot 51 has a convex shape. In such a case, the surface layer portion of the consolidated wood 50a can be polished to remove the convexly protruding portion of the knot portion 51. The compacted wood 50a has sufficient hardness even if the surface layer portion thereof is scraped off by about 0.2 to 0.5 mm.

9. Production of Next Consolidation Wood When another wood 50 is continuously consolidated, the steps [1] to [8] above may be repeated. In the method for producing compacted wood of the present embodiment, as described above, 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 step of the above [7]. Therefore, the next compaction processing of the wood 50 can be started immediately after the wood removal step of the above [8] is completed. When the compression step is performed, oil or the like exuded from the knot 51 may soak into the towel cloth 30 or the peeling cloth 40. If the towel cloth 30 or the peeling cloth 40 is dirty with oil or the like, It is preferable to replace the towel cloth 30 and the peeling cloth 40. The dirty towel cloth 30 and the peeling 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 and the like can be hardened to obtain compacted wood. In particular, many softwoods such as sugi and pine are soft and easily damaged. Therefore, when softwood is used as a raw material, the significance of adopting the method for producing compacted wood of the present invention is particularly increased. The consolidated wood obtained by the method for producing a consolidated wood of the present invention can be suitably used as a building material such as a floor board or a wall board, or a furniture material such as a tongue or a chair.

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

Claims (6)

Place the towel cloth on the upper side of the lower press plate,
Place the wood to be processed on the upper side of the towel cloth and place it.
Moisture contained in the towel cloth is impregnated into the surface layer on the lower surface side 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, which comprises compacting and hardening the lower surface side of the wood.
The method for producing compacted wood according to claim 1, wherein a peeling cloth having a surface smoother than that of the towel cloth is sandwiched between the wood and the towel cloth.
Surface density of said toweling ^{is, 0.02g / cm 2 ~2g / cm} 2 a process according to claim 1 or 2, wherein the compaction timber.
The method for producing compacted wood according to any one of claims 1 to 3, wherein a towel cloth is laid on the upper side of a lower press plate that has been preheated to a target temperature, and then the towel cloth is moistened.
The method for producing compacted wood according to any one of claims 1 to 4, wherein the upper press plate is kept at a temperature substantially equal to that of the lower press plate.
The method for producing compacted wood according to claim 5, 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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