JP2013059870A - Method for manufacturing modified woody material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a modified woody material, which can manufacture a modified woody material having high dimensional accuracy and excellent in dimensional stability efficiently in a good yield.SOLUTION: The method for manufacturing a modified woody material includes a heating treatment where a woody material 1 obtained by combining components, such as veneer, with each other is subjected to a heat treatment with a high temperature of 180°C or higher. The woody material is such as a laminated veneer lumber (LVL), plywood, or laminated lumber.

Description

  The present invention relates to a method for producing a modified wood material.

  As a method of modifying wood, high dimensional stability can be obtained by heat treating wood with a moisture content of about 50 to 200% at a high temperature around 200 ° C. for a certain period of time in addition to normal forced drying. Is known (see Patent Document 1). However, in order to obtain wood with high dimensional accuracy due to large variations in wood shrinkage during heat treatment, grinding is necessary again after the treatment, resulting in a significant reduction in yield in the manufacturing process. Moreover, the decomposition of hemicellulose progresses due to long-time heat treatment at a high temperature, resulting in a decrease in strength.

  As a heat treatment method in which such a problem is unlikely to occur, Patent Document 2 describes a method for modifying wood using high-temperature saturated steam, and Patent Document 3 describes a state of being compressed and fixed using a hot platen. A wood heat treatment method for supplying high pressure steam to wood is described. However, the heat recovery efficiency is low in the treatment with steam, and the method using the hot platen has a problem that the resin component from the wood easily adheres to the hot platen.

  In addition, a method using a chemical for improving the dimensional stability of wood has been proposed (see, for example, Patent Documents 4 and 5). However, the method using a chemical has a limited effect only by coating, and even in the case of impregnation treatment, uneven impregnation is unavoidable, and a considerable amount of impregnation is necessary to obtain a sufficient effect. This is necessary and may increase costs.

  Patent Document 6 describes that a plurality of thermowoods (heat treated wood) obtained by heat treatment for a predetermined time at a high temperature are bonded together to form a laminated material. That is, in Patent Document 6, high-temperature treatment is performed at the stage of a lumber product that is an individual element of the laminated material. Therefore, the heat-treated individual elements are likely to be warped and deformed, and it is necessary to perform a grinding process on each of them before they are bonded together.

Japanese National Patent Publication No. 9-502508 JP 2010-269593 A Publication 2004-345175 Japanese Patent Laid-Open No. 2005-199638 JP 2004-114501 A JP 2005-88228 A

  Accordingly, an object of the present invention is to provide a method for producing a modified wood material that can efficiently produce a modified wood material having high dimensional accuracy and excellent dimensional stability with a high yield.

  The present invention achieves the above object by providing a method for producing a modified wood material, characterized in that the wood material obtained by joining the constituent elements is heat-treated at a high temperature of 180 ° C. or higher. It is.

  According to the method for producing a modified wood material of the present invention, a modified wood material having high dimensional accuracy and excellent dimensional stability can be efficiently produced with a high yield.

FIG. 1 is a perspective view showing an LVL (single plate laminate) which is an example of a wood material in the present invention. FIG. 2 is a perspective view showing an end grain panel which is another example of the wood material in the present invention. FIG. 3 is a graph showing an example of temperature control when performing high-temperature heat treatment. FIG. 4 is an explanatory diagram for explaining an example of a method of manufacturing an end grain panel.

Hereinafter, the present invention will be described in detail based on preferred embodiments thereof.
In the present invention, heat treatment at high temperature (hereinafter, also referred to as high temperature heat treatment) is performed on the wood material obtained by joining the constituent elements.
As the wood material in the present invention, (1) LVL, (2) plywood, (3) laminated wood, (4) particle board, (5) fiber board, (6) OSB, (7) OSL (Oriented Strand Number) (8) LSL (Laminated Strand Number) and the like. The wood is obtained by combining the components, and does not include lumber or solid wood.

(1) LVL
LVL (Laminated Veneer Lamber) is a laminate of veneers obtained by cutting wood with a rotary lace or slicer, etc., with the fiber directions parallel to each other, and hot-pressure bonding them. It is a wood material obtained. LVL has a long shape in one direction (X direction, fiber orientation direction) like LVL (single plate laminated material) 1 shown in FIG. 1 from the viewpoint of obtaining a modified wood material used as a shaft material. Preferably it is. The modified wood material used as the shaft material is used as, for example, a pillar, a beam, a girder, a stud, a base, a joist, a purlin, a rafter, a purlin, a shed bundle, etc. in a wooden house or the like.

Although it is preferable that the orientation direction of the single plate fiber of all the layers in the thickness direction is aligned, the LVL has a fiber orientation direction in a part of the thickness direction (for example, the second layer from each of the front and back surfaces). May have a layer intersecting with another layer. However, it is preferable to have a core portion composed of a plurality of single plates laminated in parallel with the fiber direction at the center in the thickness direction, and the number of single plates constituting the core portion is the number of single plates of LVL. It is preferable that it is half or more of the total number of laminated layers. The number of laminated single plates of the entire LVL can be, for example, 7 to 32 layers, and preferably 12 to 22 layers.
As the wood species for obtaining the LVL veneer, various kinds of trees conventionally used for the production of LVL can be used without particular limitation, for example, domestic timber such as cedar, firewood, larch, and radiata pine. And foreign materials such as Russian larch and Douglas fir.

  Moreover, it is preferable that the single board which forms the front and back of LVL arrange | positions the front and back of the LVL on the front and back of the LVL. When manufacturing a veneer with a rotary lace, etc., when the veneer is spread out, fine cracks are likely to occur on the back of the wood when the veneer is expanded flat, whereas there are few such cracks on the front of the wood. Therefore, surface cracks due to aging can be reduced by arranging the front and back surfaces of the tree on the front and back surfaces of the LVL.

(2) Plywood A plywood is a woody material obtained by stacking a plurality of single plates obtained by cutting wood with a rotary lace, a slicer, or the like, and stacking them with each other so that the fiber directions are alternated.

(3) Glued Glue Glue is not limited to Glue in a narrow sense, which is made by laminating and bonding a long plate, a small square, etc. in the length, width and thickness directions with the fiber directions parallel to each other. Also included is a material in which square bars or the like are assembled and bonded in two orthogonal directions (two directions of length and width, etc.). However, the laminated material in the present invention does not include LVL and plywood.

As shown in FIG. 2, the laminated material is a block-like piece 21 obtained from a saw board or a small square piece, and the laminated ends 21a and 21b form the upper and lower surfaces 2a and 2b of the panel. An end grain panel 2 is also included.
The end grain panel is preferably made of a low specific gravity material. That is, in the end grain panel, it is preferable that a small piece as a constituent element is made of a low specific gravity material obtained from a low specific gravity tree species. If the end grain panel is composed of small pieces of low specific gravity material, it is difficult for gaps to be generated between the block-shaped small pieces during the subsequent high-temperature heat treatment. Therefore, it is possible to obtain a modified end grain panel having a high degree of adhesion between small pieces and excellent in heat insulation.
Examples of the tree species of low specific gravity raw wood include Falkata, Balsa, Kiri, Sugi, etc., with Balsa being particularly preferred. The specific gravity of the end grain panel after thermal reforming is preferably 0.08 to 0.25 g / cm ³ , particularly preferably 0.10 to 0.20 g / cm ³ . The modified end grain panel is used, for example, as a heat insulating material or an interior material in a house, a ship or the like by taking advantage of heat insulating performance and light weight.

(4) Particle board The particle board is a wood board obtained by hot pressing a piece (element) obtained by cutting or crushing wood with an adhesive to form a mat.
(5) Fiber board
The fiber board is a wood board obtained by heat-pressing a mat-like material obtained by mixing wood fibers (elements) obtained by evaporating and defibrating wood with an adhesive. Examples of the fiber board include MDF (medium specific gravity fiber board), hard board (HB), and insulation board.
(6) OSB
OSB (Oriented Strand Board, oriented strand board) is obtained by orienting, laminating and adhering elements of a thin piece of raw material. The element has a larger area and thinner shape than that used for particleboard, leaving more wood anisotropy.

  In a preferred embodiment of the present invention, each of the above-mentioned wood materials is manufactured by combining the constituent elements described above. As a method for producing a wood material, a conventionally known method for producing the wood material according to the type of the wood material can be used without any particular limitation. However, as an adhesive used for bonding components, a high-temperature heat treatment described later can be used. In this case, from the viewpoint of thermal deterioration of the adhesive, it is preferable to use a thermosetting adhesive such as a melamine resin adhesive or a phenol resin adhesive, and it is more preferable to use a phenol resin adhesive.

  Moreover, it is preferable to dry the constituent elements of the wood material until the moisture content becomes 12% or less before joining with the other constituent elements. By drying the wood material at the stage of the component alone before the heat treatment, the total processing time to obtain the modified wood material from the raw wood can be shortened. It is possible to improve the total yield until the quality wood material is obtained.

Next, heat treatment at a high temperature is performed on the obtained wood material.
The high temperature heat treatment is performed by placing the wood material at a high temperature of 180 ° C. or higher for a predetermined time. The temperature of the high temperature heat treatment is preferably 250 ° C. or lower. The time for treating the wood material at a high temperature in the range of 180 to 250 ° C. (more preferably in the range of 180 to 230 ° C.) is preferably 60 minutes or more, more preferably 1 to 5 hours, and still more preferably. Is 2 to 4 hours.
Due to the high-temperature heat treatment, the wood material is modified so that the hygroscopicity is reduced and the dimensional change or decay due to moisture absorption or water absorption hardly occurs.

  This high-temperature heat treatment includes, for example, a heating chamber that can contain a wood material, heating means that can heat the air in the heating chamber to a high temperature of 180 ° C. or higher, and the temperature in the heating chamber is changed by air exchange. A heating device provided with a temperature lowering means for lowering is preferably used. The heating chamber is preferably one in which a plurality of wood materials can be arranged in the interior with a gap between them. Moreover, it is preferable that the wood material is processed while supporting the surroundings so that air can flow. The heating chamber is preferably provided with a means for stirring the air inside so as not to cause temperature unevenness inside.

  As the heating means, an electric heater, a heating tube through which a heat medium such as steam circulates, or the like can be used. As the temperature lowering means, for example, a heat exchanger that releases the heat in the heating chamber to the outside can be provided. Further, the heating device is preferably capable of heating the wood material under atmospheric pressure.

FIG. 3 is a graph showing an example of temperature control when performing high-temperature heat treatment.
As shown in the graph of FIG. 3, the high temperature heat treatment is preferably performed through a temperature raising step, a high temperature maintaining step, and a temperature lowering step.
In the temperature raising step, the temperature in the heating chamber containing the wood material is rapidly increased to around 100 ° C. by heating combined with steam, and then the temperature in the heating chamber is increased to 180 ° in the high temperature maintaining step by heating without using steam. The temperature is gradually raised to a set temperature of ℃ or higher (215 ° C in the illustrated example).
In the high temperature maintaining process, it is preferable to maintain the temperature in the heating chamber at the set temperature (215 ° C. in the illustrated example) for a predetermined time, and in the temperature decreasing process, cooling in a heat exchanger or introducing oxygen-free gas. .

The high temperature heat treatment is continued from the time when the temperature in the heating chamber becomes 180 ° C. or higher in the temperature raising step until the temperature becomes lower than 180 ° C. in the temperature lowering step.
The high-temperature heat treatment is more preferably performed by maintaining a temperature in the range of 190 to 240 ° C. for 1 to 5 hours, and more preferably by maintaining a temperature in the range of 200 to 230 ° C. for 2 to 4 hours. The high temperature heat treatment is preferably performed until the temperature at the center of the wood material reaches 180 ° C. or higher, and more preferably, the temperature at the center of the wood reaches 190 ° C. or higher. Further, it is more preferable that the high-temperature heat treatment is performed until the temperature of the material center reaches the set temperature of the high-temperature maintenance step. In the graph of FIG. 3, “room temperature” is the temperature in the heating chamber, and “material temperature” is the temperature at the center of the wood material. The temperature at the center of the material is the temperature at the center of the cross section at the center in the longitudinal direction when the wooden material is a shaft.

The wood material is modified by such high-temperature heat treatment to obtain a modified wood material.
The above-described configuration of the heating device and how to change the temperature are merely examples, and the temperature increase rate, the temperature and time of the high temperature maintenance process, the temperature decrease rate of the temperature decrease process, etc. should be changed as appropriate. Can do.

The modified wood material after the high-temperature heat treatment is subjected to post-processing such as planar processing, chamfering processing, drilling processing, grooving processing, and actual processing as necessary.
In addition, from the viewpoint of improving the designability, a modified sheet such as a resin film or decorative paper may be attached to the modified wooden material. From the viewpoint of improving the designability and improving water resistance and weather resistance. To colored or colorless coating.

  The modified wood material produced by the method for producing a modified wood material of the present invention can be used for various applications, and there is no particular limitation on its use, but it has low hygroscopicity and excellent corrosion resistance. , Building exterior materials, wood deck materials, outdoor components such as desks, chairs, flower beds, exterior fences and flower bed fences, plant planter components, children's playground equipment components, etc. Because of its low dimensional stability and excellent dimensional stability, the various shaft members mentioned above in wooden houses, etc., face materials used as base materials for roofs, ceilings, walls, floors, etc., house interiors, exterior materials, furniture components It is preferably used as a heat insulating material, a heat insulating material used in a place with high humidity such as the inside of a ship, etc. from the viewpoint of low hygroscopicity and excellent thermal stability. It is also preferable to use it as a member that requires strength such as a handrail.

  The modified wood materials manufactured by the method of the present invention can be joined to have a large cross section, which can be used as a beam material, a girder material or the like. For example, after manufacturing a plurality of modified LVLs having a thickness of 25 mm or more, a width of 50 mm or more, and a length of 200 mm or more, a plurality of the modified LVLs are laminated in the thickness direction, and used as a shaft member having a large cross section. You can also. For bonding between the modified LVLs, the same adhesive as that used for manufacturing the LVL may be used, or a different adhesive may be used. In addition, it is also preferable that the stacked layers of the modified LVL are joined by hot pressing.

  Next, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to the following examples. In the following description, “part” means “part by mass” and “%” means “% by mass” unless otherwise specified.

1. Manufacture of LVL and modified LVL A raw veneer with a thickness of about 3 mm was obtained from Radiata Pine in a rotary race, and it was continuously introduced into a 180 ° C. roll dryer and dried to obtain a veneer with a moisture content of about 6%. Obtained. A plurality of the obtained single plates were stacked with a phenol resin adhesive interposed between the layers, and they were hot-pressed with a hot press heated at 220 ° C. to obtain an LVL with a thickness of 38 mm. Then, the LVL was cut to produce a large number of test pieces having a thickness of 38 mm, a width (dimension in the plate direction) of 75 mm, and a length (dimension in the mesh direction) of 75 mm. All the single plates constituting the LVL were parallel in the fiber orientation direction.

Some of the manufactured test pieces are left as untreated test pieces that are not subjected to high-temperature heat treatment, and the remaining test pieces are accommodated in a heating chamber, and the temperature in the heating chamber is shown in FIG. High-temperature heat treatment was performed while changing as shown in the graph.
The high temperature maintenance process of the high temperature heat treatment was terminated with the time when the material temperature reached 215 ° C., which is the set temperature of the high temperature maintenance process. The time during which the room temperature was maintained at 215 ° C. (the time for the high temperature maintaining step) was 180 minutes, and the time during which the room temperature was 180 ° C. or higher was 200 minutes.

2. Evaluation of moisture absorption and dimensional stability Eight untreated specimens and eight specimens subjected to high-temperature heat treatment were prepared and dried at 105 ° C. for 24 hours to be absolutely dry. It was immersed in warm water at 0 ° C. for 1 hour, and then left in a constant temperature and humidity room at a temperature of 20 ° C. and a relative humidity of 60% for 48 hours to adjust the humidity.
After 30 minutes of warm water immersion, 1 hour of warm water immersion, 4 hours of humidity control, 24 hours of humidity control, and 48 hours of humidity control at each time point, the mass, thickness and width of the test piece are measured, and the water absorption rate at each time point. The thickness swelling rate and the width swelling rate were calculated. Table 1 shows the average value of eight untreated specimens (comparative examples) and the average value of eight specimens (examples) subjected to high-temperature heat treatment.

The water absorption rate, thickness swelling rate, and width swelling rate were calculated according to the following formula.
Water absorption rate (%) = (A−B) / B × 100
(However, A: Mass of the test piece at each time point, B: Mass of the test piece in the absolutely dry state)
Thickness swelling rate (%) = (C−D) / D × 100
(However, C: the thickness of the test piece at each time point, D: the thickness of the test piece in an absolutely dry state)
Width swelling rate (%) = (E−F) / F × 100
(However, E: width of the test piece at each time point, F: width of the test piece in a completely dry state)

3. Evaluation of Strength (Bending Young's Modulus, Bending Strength) LVL having a thickness of 38 mm was obtained from Radiata Pine in the same manner as described in “1. Production of LVL and Modified LVL” above. However, the dimensions of the LVL were 38 mm in thickness (mesh direction), 90 mm in width (dimension in the plate direction), and 2000 mm in length (dimension in the fiber direction), and 12 or more LVLs having the same dimensions were manufactured.
Each of the 12 LVLs produced was cut at the center in the length direction, half of the LVL was an untreated test piece not subjected to high-temperature heat treatment, and the other half was subjected to high-temperature heat treatment. It was a piece. About the test piece which performs high temperature heat processing, the temperature in a heating chamber was changed like the graph shown in FIG. 3, and the high temperature heat processing similar to the above was performed.

The 12 untreated specimens thus obtained (shown as untreated 1-12 in Table 2) and the 12 specimens subjected to high-temperature heat treatment (designated as heat treated 1-12 in Table 2). ), Bending Young's modulus (GPa) and bending strength (MPa) were measured on the assumption that it is used as a structural material such as a wooden house, particularly as a main structural material. The results are shown in Table 2.
The measuring method of bending Young's modulus and bending strength was performed based on the method prescribed | regulated to the Japanese agricultural and forestry standard (JAS) regarding the structural single board laminated material. The physical property comparison was performed in the direction of vertical use, which is frequently used.
The bending Young's modulus (GPa) and bending strength (MPa) were measured after the test piece was left in a constant temperature and humidity room at a temperature of 20 ° C. and a relative humidity of 60% for 2 weeks, and the moisture content reached almost equilibrium. did. Table 2 also shows the equilibrium water content of the test pieces thus measured.
The water content was calculated according to the following formula.
Moisture content (%) = W ₁ −W ₂ / W ₂ × 100
(W ₁ : mass of the test piece before drying, W ₂ : mass of the test piece in an absolutely dry state)

4). Production of End Grain Panel (hereinafter referred to as EGP) and Modified EGP As shown in FIG. 4 (a), a plurality of small square members 20 made of balsa material are bonded between adjacent small square members 20 with a melamine resin adhesive. They were interposed and arranged in a horizontal row, and these were pressed and integrated from the horizontal direction. Next, the composite material is sequentially cut at a predetermined width from one end where the wood end face of the small-angled member 20 is located, and as shown in FIG. 4B, a rod-like intermediate body 22 in which a plurality of block-like pieces 21 are connected. I got several. Then, after changing the direction of the rod-like intermediate bodies 22 so that the end surfaces 21a and 21b of the small pieces 21 form the upper and lower surfaces of the panel, as shown in FIG. The side surfaces were joined via a melamine resin adhesive. And the circumference | surroundings of obtained EGP were cut | disconnected so that it might become a planar view rectangular shape, and thickness 35mm, width 920mm, and length 1830mm EGP were obtained.
Then, the EGP was cut to obtain 12 EGP test pieces having a thickness of 35 mm, a width of 150 mm, and a length of 150 mm.

  Of the 12 EGP test pieces, six of them were untreated test pieces that were not subjected to high-temperature heat treatment, and the remaining six pieces were test pieces that were subjected to high-temperature heat treatment. About the test piece which performs high temperature heat processing, the temperature in a heating chamber was changed like the graph shown in FIG. 3, and the high temperature heat processing similar to the above was performed.

5. Evaluation of Modified EGP Six untreated test pieces obtained in this way and six test pieces subjected to high-temperature heat treatment were dried at 105 ° C. for 24 hours to be absolutely dry. Then, it was placed in a constant temperature and humidity chamber at a temperature of 80 ° C. and a relative humidity of 90%, and absorbed for 24 hours.
About the test piece after an absolutely dry state and moisture absorption, mass, a dimension, etc. are measured, the moisture content and specific gravity of a test piece are calculated, and the thermal conductivity of a test piece is measured. The average value of the test piece (comparative example) and the average value of six test pieces (examples) subjected to high-temperature heat treatment are shown.

  The thermal conductivity was measured by a hot wire method using a thermal conductivity meter (QTM-500) manufactured by Kyoto Electronics Industry Co., Ltd.

  From the comparison of the results of Examples and Comparative Examples in Table 1, it can be seen that the modified woody material produced in the present invention has reduced moisture absorption and water absorption and improved dimensional stability against moisture absorption. Moreover, when the average value of the moisture content in Table 2 is compared, the average value of the heat treatment (Example) is 5.4% while the average value of the untreated (Comparative Example) is 11.5%. It can be seen that the modified wood material produced in the present invention is less susceptible to moisture absorption than before the modification even under a normal environment of a temperature of 20 ° C. and a relative humidity of 60%. In addition, from the comparison of moisture content values after moisture absorption in Table 3, the modified wood material produced in the present invention is difficult to absorb moisture even in a severe environment of high temperature and high humidity of 80% relative humidity 90%. I know that.

In addition, in the present invention, since the high-temperature heat treatment is performed after combining the constituent elements of the wood material into the wood material, compared with the case of high-temperature treatment to lumber or solid wood, the demerit of the high-temperature heat treatment of wood The disadvantage that the knots and the like are weakened by heating is not easily revealed, and a modified wood material having excellent strength can be obtained.
For example, Table 2 shows the case of LVL, but when the average values of bending Young's modulus and bending strength are compared, the bending strength is reduced from 65.48 MPa to 53.31 MPa due to high-temperature heat treatment. The bending Young's modulus (flexural rigidity) is improved from 11.38 GPa to 12.81 GPa by high-temperature heat treatment. The Japanese Agricultural Standards (JAS) defines the grade of structural single-plate laminates in terms of bending Young's modulus and bending strength, but the bending strength is relatively high before and after modification. While it can be easily met, the bending Young's modulus can be difficult to meet criteria. When the modified LVL is produced by the method of the present invention, the effect of being able to improve the bending Young's modulus while suppressing the decrease in bending strength to a small degree is the modified material used as a structural material, particularly as a main structural material. This is particularly useful from the viewpoint of manufacturing LVL.

Further, in the present invention, since the high-temperature heat treatment is performed after the constituent elements are combined to form a wood material, deformation such as twisting and warping hardly occurs even by the high-temperature heat treatment. Therefore, a modified wood material with high dimensional accuracy can be obtained as compared with a case where a lumber product or a solid material is subjected to high-temperature heat treatment. In the present invention, the modified wood material subjected to the high-temperature heat treatment may be subjected to a planer or a sander as a post-treatment, but the amount of cutting can be suppressed to a small amount as compared with the case where the solid material is subjected to the high-temperature heat treatment. it can. For example, the cutting amount of the single plate on the front and back surfaces of the LVL can be easily suppressed to 10% or less of the mass of the single plate.
In addition, wood materials such as LVL can be used more effectively than raw wood, so it is possible to reduce the waste caused by the planer and sander at the component stage and after-treatment stage. In combination with this, it is possible to efficiently produce a modified wood material having low hygroscopicity and excellent dimensional stability and the like with a high yield.

  Moreover, it is preferable to improve the total yield from the raw wood to the final product by performing drying at the stage of the constituent elements such as a single plate and small pieces. By drying with a large volume specific surface area such as veneer and small pieces, it is possible to combine the components with the internal stress removed, reducing deformation during high-temperature heat treatment compared to lumber products. be able to. Thereby, the yield loss in the heat treatment process can be reduced, and the total yield from the raw wood to the final product can be improved.

  Moreover, as shown in Table 3, it can be seen that the modified wood material produced in the present invention has a lower thermal conductivity than the case where the modified wood material is not modified. This is considered to be due to the water absorption and hygroscopicity of the modified wood material being reduced by the heat treatment at high temperature. However, it is difficult to reduce the thermal conductivity by the high temperature heat treatment. When a woody material is used as a heat insulating material, it means that the heat insulating performance is stably maintained for a long time. Therefore, the modified wood material produced in the present invention is also preferably used as a heat insulating material, and particularly preferably used as a heat insulating material used in a humid place. In particular, the EGP formed from the low specific gravity material described above is preferably used as a heat insulating material for a ship, for example, a heat insulating material disposed on a wall or a floor inside a ship, because the heat insulating performance is stably maintained and the weight is light. .

1 LVL (wood)
2 End grain panel (glulam, wood)
21 Block-shaped pieces (components)
21a, 21b Kiguchi surface 22 Rod intermediate

Claims (5)

  A method for producing a modified wood material, comprising heat-treating a wood material obtained by combining constituent elements at a high temperature of 180 ° C or higher.   The method for producing a modified wood material according to claim 1, further comprising a step of drying the constituent elements until the moisture content becomes 12% or less before joining the constituent elements.   The method for producing a modified wood material according to claim 1 or 2, wherein the wood material is LVL.   The method for producing a modified wood material according to claim 1 or 2, wherein the wood material is a laminated material.   The method for producing a modified wood material according to claim 4, wherein the laminated material is an end grain panel made of a low specific gravity material.

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