JP2013132751A - Method for manufacturing water repellent wooden material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide water repellent wooden material capable of maintaining the water repellent property of its surface for a long period of time, and an efficient method for manufacturing the same.SOLUTION: The water repellent wooden material is made by processing, with a water repellent, a surface of middle wooden material obtained by heat-processing the wooden material at high temperature of 180°C or higher. In the method for manufacturing the water repellent wooden material, the surface of the middle wooden material obtained by heat-processing the wooden material at high temperature of 180°C or higher is processed with the water repellent. The wooden material is, for example, laminated lumber such as an end grain panel (EGP), LVL, etc.

Description

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

As a method of imparting water repellency to the surface of wood, a method of forming a coating film on the surface of wood with a chemical having water repellency has been used for a long time, but when wood is used outdoors or parts facing the outdoors However, it is difficult to keep the water repellency for a long time because the coating film is easily broken.
As another method for imparting water repellency to the surface of wood, there is also known a method in which a music agent having water repellency penetrates into the wood and is fixed in the wood.
For example, Patent Document 1 describes a method for producing laminated wood in which a water-repellent agent is infiltrated in a single plate state and bonded again to obtain a water-repellent laminated material. Patent Document 2 discloses a water-repellent agent in a vapor state. It describes that water-repellent wood is produced by contacting the wood with wood.

  Further, a surface-coated emulsion water repellent (water repellent emulsion composition for wood) is known as an easily permeable water-based water repellent (see Patent Document 3).

  In addition, in Patent Document 4, as a technique for improving biodegradability characteristics and dimensional stability, wood having a moisture content of about 50 to 200% is subjected to heat treatment at a high temperature of about 200 ° C. for a certain period of time in addition to normal forced drying. It is described to do. Patent Document 5 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.

JP 2006-35603 A JP 2010-89269 A JP 2008-231276 A Japanese National Patent Publication No. 9-502508 JP 2005-88228 A

As in Patent Document 1, the method of impregnating and fixing a water-repellent drug inside the wood has a problem of high cost because the amount of the drug used is large and the processing equipment is large. As in Patent Document 2, there is a problem that the method of bringing the water repellent into contact with the wood in the vapor state and the processing equipment become large and the cost is high.
The method of forming a coating film on the surface of wood with a chemical having water repellency, as mentioned above, can maintain water repellency for a long period of time when wood is used outdoors or in parts facing the outdoors. difficult.

On the other hand, the surface-applied emulsion water repellent of Patent Document 3 is excellent in weather resistance and seems to be able to maintain the water repellency of the surface for a certain period even outdoors where UV exposure occurs. In the case of wood having high water absorption, sufficient water repellency is not obtained, surface cracking occurs, and water repellency is lost in a short period of time.
For example, the balsa wood end grain panel used in the state of the front and back of the culvert direction, and thinned wood of planted trees such as cedar and cypress, manufactured with materials that contain a lot of sapwood. Wood panels such as plywood and LVL have a high surface water absorption, and it is difficult to maintain a surface water-repellent state even if the surface is subjected to water-repellent treatment or wet by rain for a short time of about 1 hour. Therefore, for example, when it is used outdoors or a part facing the outdoors, the moisture content of the wood surface repeatedly increases and decreases, and surface cracks occur. And when a surface crack generate | occur | produces, a water | moisture content will penetrate | invade easily from a crack part, and also a surface crack will advance deep inside.
On the other hand, the use of highly water-absorbing tree species in planted trees for building materials used for outdoor and outdoor-facing parts will reduce the cutting of highly durable natural trees that are currently used. It is preferable from a viewpoint of doing.

  Patent Documents 4 and 5 do not describe improvement in water repellency. Further, in Patent Document 5, high temperature treatment is performed at the stage of the lumber product, which is an individual element of the laminated lumber, and therefore, the individual heat treated elements are easily warped and deformed, and before bonding them, Glulam cannot be produced efficiently because it is necessary to grind each of them.

  Accordingly, an object of the present invention is to provide a water-repellent wood material capable of maintaining the water repellency of the surface for a long period of time and an efficient manufacturing method thereof.

The present invention achieves the above object by providing a water repellent wood material obtained by treating the surface of a wood material modified by heat treatment at a high temperature of 180 ° C. or higher with a water repellent.
The present invention also provides a method for producing a water-repellent wood material, characterized in that the surface of the intermediate wood material is modified by heat treatment at a high temperature of 180 ° C. or higher and treated with a water repellent. This achieves the above object.

  According to the water repellent wood material of the present invention, a water repellent wood material capable of maintaining the water repellency of the surface for a long period of time is provided. According to the method for producing a water repellent wood material of the present invention, it is possible to efficiently produce a water repellent wood material capable of maintaining the surface water repellency for a long period of time.

FIG. 1 is a perspective view showing an end grain panel as an example of a wood material in the present invention. FIG. 2 is a perspective view showing an LVL 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.
The water repellent wood material of the present invention is obtained by treating an intermediate wood material obtained by heat treating a wood material at a high temperature of 180 ° C. or more with a water repellent.
Wood materials used in the present invention include (1) laminated wood, (2) LVL, (3) plywood, (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) Glued Glue Glue is not limited to Glue in the sense of length, width, and thickness, but in the direction of parallel to each other in the direction of fibers, small squares, etc. It also includes a structure in which square bars and the like are assembled and bonded in two orthogonal directions (two directions of length and width, two directions of length and thickness, etc.). However, the laminated material in the present invention does not include LVL and plywood.

As shown in FIG. 1, a block-like piece 21 obtained from a saw board or a small square piece is laminated on the laminated material so that both the end surfaces 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 (gathered material) after the high-temperature heat treatment is preferably 0.08 to 0.25, particularly preferably 0.10 to 0.20.
(2) 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. From the viewpoint of obtaining a water-repellent wood material used as a shaft material, LVL has a long shape in one direction (X direction, fiber orientation direction) like LVL (single plate laminate) 3 shown in FIG. It is preferable.

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.

(3) Plywood plywood is a woody material obtained by stacking a plurality of single plates obtained by cutting wood with a rotary lace or a slicer so that the fiber directions are staggered and hot-press bonding.

(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.

A preferred embodiment of the method for producing the water repellent wood material of the present invention (preferred method for producing the water repellent wood material of the present invention) will be described.
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 at the stage of the component alone before applying heat treatment to the wood material, the total treatment time from obtaining the raw wood material to the intermediate wood material or water repellent wood material can be shortened, Further, it is possible to improve the total yield from obtaining raw wood material to intermediate wood material or water repellent wood material.

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.
An intermediate wood material is obtained by this high-temperature heat treatment. The intermediate wood material is a production intermediate of a water-repellent wood material, which is a wood material after heat treatment at a high temperature of 180 ° C. or more and before the water repellent treatment.
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, a heating means that can heat the air in the heating chamber to a high temperature of 180 ° C. or higher, and a temperature-lowering means that lowers the temperature in the heating chamber. The heating device provided is preferably used. The heating chamber is preferably one in which a plurality of wood materials or a plurality of wood materials can be arranged 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 increased to 100 ° C. at a stretch by heating combined with steam, and then the steam heated by the electric heater is sent to change the temperature in the heating chamber, The temperature is gradually raised to a set temperature of 180 ° C. or higher (215 ° C. in the illustrated example) in the high temperature maintaining process.
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 while maintaining a temperature in the range of 190 to 240 ° C. for 1 to 5 hours, and more preferably performed while 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 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.

Next, the surface of the obtained intermediate wood material is treated with a water repellent. Examples of the surface treatment with the water repellent include water repellent coating by various known coating methods such as brush coating, roller coating, spray coating, and roll coater coating. Alternatively, the intermediate wood material may be immersed in a water repellent and the water repellent applied to the surface of the intermediate wood material.
The water repellent is preferably applied to the surface of the intermediate wood material to which water repellency is to be applied so that the water repellent is uniformly applied to the surface. The coating amount of the water repellent is preferably 50 to 300 g, particularly 100 to 200 g per 1 m ² from the viewpoint of shortening the drying time after coating and imparting sufficient water repellency. The amount of water repellent applied here is the amount when the water repellent is diluted 1 to 20 times with water on the surface of the intermediate wood material.
In addition, the water repellent is applied after the surface of the wood material (intermediate wood material) that has been subjected to the high-temperature heat treatment is subjected to a smoothing treatment with a planar or the like, if necessary.

As the water repellent, various known wood water repellents such as a fluorine water repellent and a silicone water repellent can be used, but it is preferable to use a penetrating water repellent, In particular, it is more preferable to use a silicone-based penetrating water-based water repellent.
The penetrating water-based water repellent is not an organic solvent-based one, and penetrates deeper than the painted surface (the surface of the intermediate wooden material) to form a water-repellent layer (for example, fluorine resin or silicone) inside the wooden material. A layer made of rubber).
Therefore, it is environmentally friendly and human-friendly compared to organic solvent-based materials, and it can retain moisture absorption and release functions of wooden materials compared to film-forming materials that form a film on the surface of the painted surface. Is easy to maintain.

  Further, the water repellent is preferably allowed to penetrate at least 1 mm or more from the painted surface (the surface of the intermediate wood material), more preferably to a depth of 1 to 4 mm.

Examples of the silicone-based penetrating water-based water repellent include water-repellent emulsion compositions for wood described in Patent Document 3, those described in JP-A-2006-328406, and penetrability manufactured by Utopia Building Materials Co., Ltd. An inorganic protective agent “Wood Tough (trade name)” and the like can be exemplified, but are not limited thereto. Wood tough is an aqueous solution containing a siliceous component and penetrates into the applied woody material to form glassy crystals.
Silicone water-based water repellents are more environmentally friendly and human-friendly than organic solvent-based water repellents, and can easily penetrate deeper than the painted surface. It is preferable from the viewpoint that a water-repellent wood material having further excellent durability can be obtained and re-application during maintenance is easy.

  As the water repellent, it is also preferable to use an aqueous (aqueous) emulsion composition containing an organosiloxane. Moreover, as an example of such a water repellent, the water repellent emulsion composition for wood of patent document 3 is mentioned. The water repellent emulsion composition for wood described in Patent Document 3 is (A) organopolysiloxane containing at least two hydroxyl groups bonded to silicon atoms in one molecule: 100 parts by mass, (B) containing amino groups Reaction product of organoalkoxysilane and acid anhydride: 1 to 10 parts by mass, (C) epoxy group-containing organoalkoxysilane and / or partial hydrolyzate thereof: 0 to 10 parts by mass, (D) colloidal silica and / or Or polysilsesquioxane: a water repellent emulsion composition for wood, which is obtained by emulsifying and dispersing 0 to 40 parts by mass in water in the presence of a surfactant, and does not contain a tin compound. Specific examples of the components (A) to (D) and more preferable blending ratios are as described in Patent Document 3.

The water-repellent agent may be applied after the wood material (intermediate wood material) after the high-temperature heat treatment is cooled to room temperature (for example, 35 degrees or less), but in a state where the heat from the high-temperature heat treatment remains. This is also preferable from the viewpoint of shortening the water repellent treatment time.
However, since there are various obstacles in applying to a wood material in a high temperature state, the temperature of the wood material after the high temperature heat treatment (particularly the temperature inside the wood, for example, the material temperature in FIG. 3) is 100 to 40. It is preferable to carry out at the stage of ° C, and it is more preferred to carry out at a temperature of 70-50 ° C.

After application of the water repellent, the water repellent is naturally dried. When a water repellent is applied to a woody material (intermediate woody material) that has been cooled to room temperature, drying may be accelerated by moderately heating (eg, 40 to 80 ° C.).
In this way, the water-repellent wood material of the present invention is obtained. The water-repellent woody material of the present invention exhibits water repellency stably for a long time by treating the woody material at a high temperature before it is treated with a water repellent.

The water repellent wood material 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 designability, a water-repellent wood material may be attached with a decorative sheet such as a resin film or decorative paper, which improves designability and improves water resistance and weather resistance. Colored or colorless coating may be applied from the viewpoint.

In the preferred method for producing the water-repellent wood material described above, since the high temperature heat treatment is performed after the constituent elements are combined to form the wood material, deformation such as twisting and warping is hardly caused even by the high temperature heat treatment. Therefore, a water-repellent 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 a high-temperature heat treatment. As a post-treatment, a planer or a sander may be applied to the intermediate wood material subjected to the high-temperature heat treatment, but the amount of cutting can be reduced to a small amount as compared with the case where the solid wood is subjected to the high-temperature heat treatment. 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 end grain panels and LVL can be used more effectively than raw wood, so it is possible to use wood or planer at the component stage or after-treatment stage. Combined with the fact that waste can be reduced, a water-repellent wood material excellent in water repellency durability can be efficiently produced with a high yield.

  The water-repellent wood material of the present invention or the water-repellent wood material produced by the method of producing the water-repellent wood material of the present invention can be used for various applications, and there is no particular limitation on the use, but moisture absorption Because of its low resistance and excellent decay resistance, building exterior materials, wood deck materials, outdoor desks, chairs, flower bed components, exterior fences and flowerbed fences, plant planter components, children From the point that it is used as a component of playground equipment, etc. or has low hygroscopicity and excellent dimensional stability, the above-mentioned various shaft members in wooden houses, etc., face materials used as base materials such as roofs, ceilings, walls, floors, Insulation materials used in damp places such as interiors, interiors of ships, etc., because they are used as building interiors, exterior materials, furniture components, etc., and have low hygroscopicity and excellent thermal stability. It is preferable to use as. It is also preferable to use it as a member that requires strength such as a handrail.

  The water-repellent wood materials produced by the method of the present invention can be joined together to make a large cross section, which can be used as a beam material, a beam 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.

(1) Manufacture of end grain panel (hereinafter referred to as EGP) and intermediate wood material (hereinafter referred to as intermediate EGP) using the same, as shown in FIG. The melamine resin adhesive was interposed between the adjacent small square members 20 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 to obtain EGP having a thickness of 25 mm, a width of 920 mm, and a length of 1830 mm.
The EGP was cut to produce a number of EGP test pieces having a thickness of 25 mm, a length of 320 mm, and a width of 320 mm.

(2) Manufacture of water-repellent wood material EGP test pieces are divided into a group that performs high-temperature heat treatment and a group that does not perform high-temperature heat treatment. As shown in the graph, the same high-temperature heat treatment as above (heat treatment at 215 ° C. for 3 hours) was performed. About the group which does not perform high temperature heat processing, high temperature heat processing was not performed and heat processing at low temperature was not performed.

Example 1
Apply water repellent (trade name Wood Aid) manufactured by Shin-Etsu Chemical Co., Ltd. 7.5 times with water on one side (320mm x 320mm side) of a test piece that has been subjected to high temperature heat treatment, and dry naturally Thus, a water-repellent woody material was obtained. The water repellent was applied once so that the coating amount was 100 g / m ² .
(Example 2)
In Example 1, a water repellent wood material was prepared in the same manner as in Example 1 except that the water repellent was applied twice at 100 g / m ² and the total amount of water repellent was 200 g / m ^2. Obtained.

(Comparative Example 1)
A water-repellent wood material was obtained in the same manner as in Example 1 except that the test piece that was not subjected to the high-temperature heat treatment was used.
(Comparative Example 2)
A water-repellent woody material was obtained in the same manner as in Example 2 except that a test piece that was not subjected to high-temperature heat treatment was used.

(Comparative Example 3)
The test piece subjected to the high-temperature heat treatment was evaluated without applying a water repellent.

(Comparative Example 4)
The test pieces that were not subjected to the high temperature heat treatment were evaluated without applying a water repellent.

(3) Evaluation of initial water repellency The obtained water-repellent woody material was subjected to a water repellency (water repellency) test according to the “water repellency test method for paper and paperboard” prescribed in JIS P8137: 1976. The water repellency was evaluated.
That is, the test piece was fixed in a state inclined at 45 °, and a drop of 20 ° C. distilled water was dropped from a burette adjusted to about 0.1 mL with respect to the test piece. Flow down 300 mm above. The trace of the flow is observed, and the water repellency (water repellency) is determined according to the following evaluation criteria described in the table described in JIS P8137: 1976. This test is performed five times in each direction (longitudinal direction and lateral direction) of each test piece, and the maximum value (the one closest to R10 among the evaluations R0 to R10) and the minimum value (the most among the evaluations R0 to R10). Values close to R0) and average values are shown in Table 1.

(Evaluation criteria)
R0: continuous traces showing a uniform width R2: continuous traces showing a slightly narrower width than water drops R4: continuous traces that are somewhat cut off and clearly narrower than water drops Indicates the width.
R6: A half of the trace is wet R7: A quarter of the trace is wet by a long water drop R8: A quarter or more of the trace is scattered with spherical droplets R9: Somewhere, small spherical water droplets are scattered R10: Things that roll down completely

(4) Evaluation of durability of water repellency In the above test, instead of dropping one drop of water on each test piece, a total of 20 drops of water from the burette at intervals of 30 seconds are placed at the same place on each test piece. The durability of the water repellency was evaluated in the same manner as in the above test, except that the trace of flow-down was observed at the time of dropping and dropping 20 drops. The results are shown in Table 2.

  Regarding the initial water repellency, it can be seen from the comparison of the results of Comparative Examples 3 and 4 and Tables 1 and 2 in Table 1 that the water repellency increased and the water repellency improved by performing the water repellency treatment. Comparing the results of Examples 1 and 2 and Comparative Examples 1 and 2, Comparative Examples 1 and 2 also show high water repellency, and the effect of improving water repellency by high-temperature heat treatment is not clear.

On the other hand, regarding the durability of water repellency, when the results of Examples 1 and 2 and Comparative Examples 1 and 2 in Table 2 are compared, Examples 1 and 2 are clearly more water-repellent than Comparative Examples 1 and 2. It can be seen that the durability of the water repellency was improved by the high-temperature heat treatment.
Further, comparing the results of Comparative Example 1 and Comparative Example 2, it can be seen that when the application amount of the water repellent is halved, the water repellency is lowered and the water repellency is lowered. On the other hand, looking at the results of Example 1 and Example 2, the difference in water repellency is slight even if the amount of water repellent applied is halved. From this, it can be seen that according to the present invention, even if the amount of the water repellent is small, excellent durability is obtained and the water repellency of the surface of the wood material is maintained for a long period of time.

2 End grain panel (glulam, wood)
21 Block-shaped pieces (components)
21a, 21b Wood end 22 Bar-shaped intermediate 3 LVL (wood material)

Claims (7)

  A water-repellent wood material obtained by treating a surface of an intermediate wood material obtained by heat-treating a wood material at a high temperature of 180 ° C. or more with a water repellent.   A method for producing a water repellent wood material, characterized in that a surface of an intermediate wood material obtained by heat-treating a wood material at a high temperature of 180 ° C. or higher is treated with a water repellent.   The method for producing a water repellent wood material according to claim 2, wherein the water repellent is an osmotic water-based water repellent.   The method for producing a water-repellent wooden material according to claim 2 or 3, wherein the components are dried until the moisture content becomes 12% or less before the components of the wooden material are combined. .   The method for producing a water-repellent wood material according to any one of claims 2 to 4, wherein the wood material is a laminated material.   6. The method for producing a water repellent wood material according to claim 5, wherein the laminated material is an end grain panel made of a low specific gravity material.   The method for producing a water-repellent wood material according to any one of claims 2 to 4, wherein the wood material is LVL.

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