JP3062369B2 - Wood material heat treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heat-treating a wooden material, and more particularly, to a method for improving the dimensional stability or surface characteristics of a wooden material, which is suitable for building or furniture. The present invention relates to a method for heat-treating a wooden material obtainable by the method.

[0002]

2. Description of the Related Art In recent years, high-quality hardwood materials have been reduced and a sufficient supply has not been obtained, and consequently, softwood materials, medium fiberboard (MDF), particle boards, and the like have been attracting attention as alternative materials to hardwood materials. However, softwoods are generally softer than hardwoods, and surface properties such as surface hardness and surface abrasion resistance,
There were problems in durability against moisture and heat, strength, and the like.
Swelling in the thickness direction with respect to moisture was a major problem for MDF and particle board.

[0003] For this reason, if the conifer is boiled or softened by steam treatment, the conifer is condensed to a thickness of about 20 to 70% of the initial thickness by hot pressing with a flat plate press. Is known. The consolidation of softwood has remarkable effects on the surface properties, durability and strength described above, but the force of the softwood consolidated by the action of one or both of moisture and heat to return to the original state , And there was a drawback that the coniferous material which had been compacted and improved in performance was restored to near the original state.

[0004] Restoration of the compacted softwood, MDF,
In order to prevent swelling of the particle board in the thickness direction, it has been attempted to subject these wood materials to a chemical treatment such as acetylation or formalization.However, this method is environmentally preferable because it uses a large amount of chemicals. There are drawbacks such as lack of uniformity, difficulty in performing uniform treatment on the entire wood material, and complicated processing steps leading to high costs. In the case of consolidated softwood, phenol resin,
Attempts have been made to impregnate with a polyester resin or the like and apply WPC (wood / plastic composite material) treatment.
This method also has the drawback that it is difficult to uniformly treat the whole wood material similarly to the above-mentioned chemical treatment, the processing step is complicated and the cost is high, and the wood material is excellent in heat insulation and air permeability. There was also a disadvantage of losing characteristics.

As another method, there is a method of placing the compacted wood material in an autoclave and treating it with high-pressure steam at 160 to 220 ° C. for several minutes to prevent the compacted wood material from being restored. Is difficult to penetrate high-pressure steam into the wood (particularly the center of the wood), the treatment effect is not uniform, and the treatment state of the center and the periphery of the wood is often different.

[0006] The applicant of the present invention has conducted intensive studies to solve the inconvenience of the conventional method of treating wood material, and not only can prevent the compacted wood material from being restored to the original thickness due to moisture or heat, A new method of processing wood materials capable of processing wood materials uniformly and efficiently over the entire wood material has been proposed and already filed (Japanese Patent Application No. 4-26922).
No. 5).

This treatment method is a method of treating a wood material by heating a compression-molded wood material in a closed pressure vessel in a high-frequency manner while restraining deformation to convert water inside the wood material into high-pressure steam. As a result, surface properties such as surface hardness and abrasion resistance of the surface are improved, and it is possible to obtain a compacted wood material suitable for construction or furniture, which has a reduced coefficient of expansion with respect to moisture and heat.

[0008]

The above-mentioned treatment method is practically effective, but requires a step of treating wood material in a pressure vessel, so that the process is complicated and the apparatus itself is large. It had to be large.
The inventor of the present invention has continued his research on the processing method of the wood material, without using the wood material in the pressure vessel, using only a pressing device using a hot plate and using simple accessories, He has filed the application, recognizing that it is possible to obtain a wood material with a reduced expansion coefficient as low as that when treated in a pressure vessel, that is, improved dimensional accuracy and improved surface characteristics. Since it is necessary to use an elastic sealing material that is expensive and needs to be replaced as appropriate according to the number of times of use and use conditions as a sealing material, it is not only troublesome to work but also expensive in terms of cost, and there is room for improvement. Recognized.

An object of the present invention is to solve the above-mentioned problems, and has a processing mode that is easier to handle.
An object of the present invention is to provide a processing method for obtaining a wood material having improved dimensional accuracy and improved surface characteristics.

[0010]

That is, the present invention relates to a wooden material, a frame positioned on the hot platen side of the wooden material and capable of compressing the vicinity of the periphery of the wooden material, and a frame positioned around the wooden material. A thickness regulating jig that regulates the moving distance of the hot platen is arranged, and the hot plate is moved so that the frame is compacted in the vicinity of the peripheral portion of the wooden material, and the wooden material is transferred from the hot plate surface to the wooden material. Disclosed is a method for heat-treating a wooden material, which comprises supplying high-pressure steam to the wooden material.

[0011] The present invention also relates to a wooden material, a frame positioned on the hot platen side of the wooden material and capable of compressing the vicinity of the periphery of the wooden material, and a heat source positioned around the wooden material. A thickness regulating jig for regulating the moving distance of the board is arranged, and the heating board is moved so that the frame body is compacted in the vicinity of the periphery of the wood material. A wood heat treatment method characterized in that the wood is heated by high-frequency heating including:

A wooden material having a thickness greater than the height of the thickness-controlling jig may be used. In this case, the pressure density in the vicinity of the peripheral portion is higher than the pressure density in other portions. In this state, it is possible to obtain a wood material in which the whole is further compacted. In the present invention, it is also possible to provide a drug together with high-pressure steam, and at this time, the drug can be uniformly treated on the whole wood material, so that the disadvantages of the conventional chemical treatment can be solved at the same time. Can be.

Next, the present invention will be described in more detail with reference to the drawings. In the present invention, the wood material includes not only solid wood but also processed materials such as MDF and particle board, and the object can be achieved equally. The present invention is particularly effective when applied to softwoods, which are generally considered to be soft as solid wood, but can also be applied to hardwoods.

As the hot plate, a hot plate capable of supplying high pressure steam from the surface, which is usually used for pressing wood or manufacturing a composite material, may be used arbitrarily, but is not limited thereto. In carrying out the present invention, a frame is provided which is located on the hot platen side of the wooden material and which can compress the vicinity of the peripheral edge of the wooden material. This frame 10 is shown in FIG.
As shown in the figure, the shape of the outer edge of the wooden material 20 to be treated is substantially the same as that of the wooden material 20. The thickness h and the width w are selected in consideration of the permeability and compressibility of the wooden material. You.
Further, as the material of the frame 10, any material may be used as long as it has appropriate rigidity and heat resistance, but an aluminum material, a stainless material, or the like is preferable, and a stainless material is particularly preferable.

Further, a thickness regulating jig 30 (FIG. 2) having the same height as the thickness of the wood material is prepared as a desired final product. As the material of the thickness regulating jig, any material having the required rigidity and heat resistance can be used, but an aluminum material, a stainless material, or the like is preferable, and a stainless material is particularly preferable. In the case of the first embodiment of the present invention, when starting the process, first, as shown in FIG. 2A, the frame 10 is arranged on the hot platen 1a below the pressing device. The wooden material 20 to be processed is disposed thereon with the outer peripheral edges thereof being aligned, and another frame body 10 is disposed on the wooden material 20 with the outer peripheral edges aligned. Next, a thickness regulating jig 30 having the same height as the thickness of the wooden material 20 as a final product is arranged around or on both sides of the wooden material 20. High-pressure steam v is ejected from the surface of the hot platen while the hot platens 1a and 1b are moved until they come into contact with the frame 10, and are absorbed in the wood material. As a result, the wooden material 10 is softened.
Close the hotplate until regulated by. FIG. 2B shows the state.

In the above description, it is described that the initial thickness of the wooden material 20 is larger than the thickness of the thickness regulating jig 30. Therefore, in the state shown in FIG. 2B, the wooden material 20 receives the consolidation of the difference between the initial thickness of the wooden material 20 and the thickness of the thickness regulating jig 30 as a whole, and
The vicinity of the outer peripheral edge of 0 is further subjected to a consolidation action by the thickness of the frame 10 in the thickness direction. As a result, the density in the vicinity of the outer peripheral edge becomes higher than that in other portions, and the airtightness is improved.

In the state shown in FIG. 2B, high-pressure steam v is further jetted from the surfaces of the hot plates 1a and 1b toward the wooden material. As described above, since the vicinity of the outer peripheral edge is higher in density and airtightness than other portions, the portion can have a sealing function. Therefore, an expensive elastic sealing material such as an elastic silicon material, such as an elastic silicon material, which needs to be appropriately changed according to the number of uses and usage conditions, is spouted from the surface of the hot platen on the four circumferential sides of the wooden material. The high-pressure steam does not leak out of the wood, and most of it is effectively encapsulated in the wood. The jetting of the high-pressure steam may be performed stepwise by changing the jetting conditions (time, temperature, pressure, amount, etc.).

The steam v ejected as described above is
The permeation penetrates from the surface of No. 0 to the central part of the inside and is sealed therein to perform necessary processing. The treatment conditions are determined optimally experimentally depending on the type and size of the target wood material, but in the case of ordinary softwood, the temperature of the hot platen during injection of high-pressure steam is 150 ° C to 250 ° C. And the pressure of the high-pressure steam is several kgf / cm ² to
The pressure is preferably 30 kgf / cm ² and the temperature is about 150 ° C. to 230 ° C. When the supply of high-pressure steam is performed stepwise in the first step and the second step, 5 kgf / cm ^{2 to} 7 kgf in the first step.
/ cm ^2, in the second step preferably to such a 10kgf / cm ² ~30kgf / cm ² approximately. Further, the injection time of the high-pressure steam is preferably about 1 to 10 minutes.

When supplying to high-pressure steam, an agent for chemical treatment such as acetylation and formalization, and an agent for plasticizing such as ammonia gas and low-molecular-weight phenol may be simultaneously provided. The chemical is impregnated uniformly throughout the wood with the high-pressure steam. In the above description, the wood material 20
Has been described as having an initial thickness greater than the height of the thickness regulating jig 30, but the initial thickness of the wood material placed on the hot plate is approximately the same as the thickness of the desired final product. There may be. When consolidation treatment such as softwood is required to improve the surface condition together with densification, it is preferable to prepare a material thicker than the thickness of the final product as shown in the figure, such as particle board or MDF. In the case of a material that does not particularly require consolidation, a material having a thickness substantially equal to the thickness of the final product is prepared. In that case, only the outer peripheral edge portion is subjected to the consolidation process by the action of the frame body 10.

Further, in the case of a material produced by reworking an intermediate material such as MDF or particle board as the material, the treatment according to the present invention may be performed in the process of forming into a wooden material, and the material may be produced as a wooden material. The post-treatment may be performed on the processed material (therefore, in the present invention, the term "wood material" is used as including the intermediate material in the molding process).

After the supply of the predetermined high-pressure steam is completed, the pressure is released. The decompression may be performed gradually over a certain period of time, or may be performed in a so-called cold state by supplying cooling water to a hot platen. According to the experiment, the dimensional change rate of the final product obtained in the case of decompression in the cold state was smaller than that in the case of decompression gradually. In the second aspect of the present invention, the wooden material is heated by the hot plate and / or high-frequency heating without supplying high-pressure steam from the surface of the hot plate so that the moisture inside the wooden material is vaporized. In this case, when a hot plate capable of supplying high-pressure steam is used, only heating of the hot plate without supplying steam, only heating by a hot plate having no high-pressure steam supply function, or a conventional hot plate is used. In the case of a hot plate capable of high-frequency heating, the second embodiment of the present invention is implemented by only high-frequency heating or heating by both heating of the hot plate and high-frequency heating. Other conditions are the same as those described in the first embodiment, and a description thereof will not be repeated.

[0022]

The present invention will be described below with reference to examples. [Example 1] Water content 20%, thickness 30mm, width 150mm,
A plurality of cedar materials having a length of 600 mm were prepared. In addition, thickness 2m
Using a stainless steel material having a width of 10 mm and a width of 10 mm, a frame 10 for consolidation as shown in FIG. 1 was produced in the same shape as the outer shape of the wooden material.

The frame was placed above and below a wooden material on a lower heating plate of a pressing device having a heating plate capable of supplying high-pressure steam from the surface. In addition, the height 12
A stainless steel material having a thickness of 50 mm and a width of 50 mm was arranged as a thickness regulating jig. After setting the hot plate to 180 ° C, move the hot plate,
High-pressure steam of 180 ° C. at a temperature of about 10 kgf / cm ² and a temperature of about 180 ° C. was jetted from the surface of the hot platen for 2 minutes while the hot platens were moved until they contacted the frame. After that, the hot platen was gradually approached until the platen was regulated by the thickness regulating jig. As a result, the cedar wood was compacted to a compressibility of 60%.

In this state, 10 kgf /
cm ^2, the injection of high pressure steam at a temperature of about 180 ° C., 4, 6,
Continued for 8 minutes. After the injection, the pressure was gradually released for 5 minutes while cooling water was supplied to the hot platen. After decompressing, each of the final products was boiled in a boiling furnace for 2 hours, and then dried completely. The thickness of each product was measured, and the thickness swelling ratio and the recovery ratio in the radial direction were measured at the end and the center by the following formulas. . The results are shown in Tables 1 to 3.

Thickness swelling ratio = (thickness after boiling for 2 hours−absolute dry thickness before boiling) / (absolute dry thickness before boiling) × 100% Recovery rate = (thickness after boiling for 2 hours and absolute drying−) Thickness after consolidation) /
(Thickness before consolidation−thickness after consolidation) × 100% Further, for each material, the time required from the start to the end of the treatment was measured for each group. The results are also shown in Tables 1 to 3. [Comparative Example 1] The same procedure as in Example 1 was carried out except that an elastic silicone material having a height of 32 mm and a width of 30 mm was arranged as a sealing member on four circumferences of the same cedar material used in Example 1 without using the consolidation frame 10. 1
The same processing was performed and the same measurement was performed. Table 1 shows the results.
4-6.

Example 2 The same cedar material as in Example 1 was used, and the same compression frame and thickness regulating jig were prepared.
The frame was placed between the hot plates of a pressing device capable of high-frequency heating and above and below the wooden material. 13.56MH
Heating was performed for 2 minutes with a high frequency of z, output 200 kw.
Thereafter, it was gradually pressed to consolidate to a compression ratio of 60%. Subsequently, heating was performed for 4, 6, and 8 minutes using the same high frequency. In each case, the pressure was gradually released over 5 minutes while cooling water was supplied to the hot platen. After decompression, the same measurement as in Example 1 was performed for each cedar material. The results are shown in Tables 7 to 9.

COMPARATIVE EXAMPLE 2 The same cedar wood as used in Example 1 was used for four rounds, with a height of 32 mm, without using the frame 10 for consolidation.
The same processing and the same measurement as in Example 1 were performed, except that an elastic silicon material having a width of 30 mm was arranged as a sealing member.
The results are shown in Tables 10 to 12.

[0028]

[Table 1]

[Consideration] As can be seen from Table 1, Embodiment 1
In both cases, wood materials having substantially the same characteristics as those in Comparative Examples 1 and 2 were obtained. This means that it is possible to obtain a treated wood material having the same physical properties as when it is used without using expensive silicone packing that needs to be replaced frequently. The trouble of handling difficult sealing materials has been eliminated, and the cost can be reduced. In particular, when a frame made of stainless steel is used, it can be used semipermanently repeatedly, so that the economic effect is further improved.

[0030]

According to the method of the present invention, it is possible to heat-treat a wooden material using a hot plate without using an expensive and difficult-to-handle sealing material such as elastic silicone packing.
This results in reduced costs as well as ease of processing. The effect is particularly remarkable when a stainless steel frame is used.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an arrangement of a compression frame and a wooden material.

FIG. 2 is a diagram illustrating a processing state.

[Explanation of symbols]

1a, 1b: hot plate, 10: frame, 20: wood, 30 ...
Thickness control jig, V… High pressure steam

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-60-180802 (JP, A) JP-A-2-192906 (JP, A) JP-A-4-113809 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B27K 1/00-5/06 B27N 7/00

Claims (4)

(57) [Claims] 1. A wooden material, a frame positioned on the hot platen side of the wooden material and capable of compressing the vicinity of the periphery of the wooden material, between the hot plates, and movement of the hot plate positioned around the wooden material A thickness regulating jig for regulating the distance is arranged, and in a state where the hot plate is moved and the frame body is compacted in the vicinity of the periphery of the wood material, high-pressure steam is applied to the wood material from the hot plate surface. A heat treatment method for wood material, which is provided. 2. The method according to claim 1, wherein the chemical is provided together with the high-pressure steam. 3. A wooden material, a frame positioned on the hot platen side of the wooden material and capable of compressing the vicinity of the periphery of the wooden material, between the hot plates, and movement of the hot plate positioned around the wooden material A thickness regulating jig for regulating the distance is arranged, and the hot plate is moved so that the frame body is compacted in the vicinity of the periphery of the wood material.
Alternatively, a method for heat treating a wooden material, wherein the wooden material is heated by high frequency heating. 4. The method according to claim 1, wherein a thickness of the wood material is larger than a height of the thickness regulating jig.