JP3152882B2 - Wood molding 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 molding wood, and more particularly to a method for molding a wood product having a high surface hardness and excellent appearance.

[0002]

2. Description of the Related Art In order to improve the physical properties of soft wood such as cedar, compression and densification of softened wood, so-called consolidation, has been known for a long time and has been practiced industrially.
For example, according to JP-A-3-295605, a cedar log is heated and softened, compressed by a mold and formed into a polygonal cross-sectional shape, and then fixed by drying or cooling and reheating. According to Japanese Patent Application Laid-Open No. Hei 3-231802, Japanese cedar wood is heated and softened in saturated steam at 5 to 25 atm, compressed between a pair of molds and formed into a polygonal cross section. And heat it to about 180 ° C. to fix the shape. In each case, the shaped prism is
There is an advantage that the surface hardness is higher than that of the cedar logs obtained by cutting, and no cutting chips are generated during processing.

However, in the above-mentioned method, if the heat-softened wood is taken out of the mold immediately after the completion of the compression, there is a problem that the wood is reduced in volume and expanded, and it is difficult to perform a desired compaction. . Therefore, various methods for suppressing volume relaxation of wood have been attempted. For example, a method of circulating cooling water inside the mold while holding the compressed wood in the mold and removing the wood from the mold when the temperature of the wood falls below the softening point, or holding the compressed wood in the mold In this method, the compression structure is fixed by performing a wet heat treatment under a high temperature of about 180 ° C. and saturated steam for about 10 minutes, and then the mold is cooled and the molded product is taken out. Both methods have a problem that the residence time of the wood in the mold becomes long, and the efficiency of processing a large amount of wood is low, and the production cost is high.

[0004] In order to shorten the residence time of the wood in the mold, there is known a method of providing a volume relaxing jig inside the mold. The jig is configured to fix the wood at the same time as the compression of the wood, and the wood is cooled together with the jig to fix the shape. However, when the molded product has an elongated shape such as a cylinder or a prism that is frequently used in wooden construction, the volume relaxing jig is large and expensive, and is not economical.

[0005]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention provides a wood molded product having high hardness and beautiful appearance.
Without using a mold in the process of compressing wood,
It is an object of the present invention to provide a method for manufacturing a wood molded product that can be economically manufactured.

[0006]

SUMMARY OF THE INVENTION There are two inventions proposed here. In the first invention, wood has a water content of 10 to 80%.
Water content adjustment step, the water content of both lips of the wood is adjusted, the application of paint containing a polymer having a low moisture permeability and good adhesion to wood, or water permeation A water-proofing step of covering with a hard rubber sheet or film, a pressurizing and compressing step of guiding the wood after the water-proofing treatment into a liquid and compressing the liquid in a softened state by a hydrostatic pressure of the liquid, and a pressure of the liquid. A liquid pressure constant liquid temperature lowering step of fixing the compressed structure of the wood by lowering the wood in the liquid to a temperature lower than the softening temperature of the wood under the compressed state by lowering the liquid temperature while maintaining the wood, The present invention relates to a method for forming wood, comprising a step of taking out wood to be taken out.

[0007] In the second invention, wood has a water content of 10%.
A water content adjusting step of adjusting the water content to 80%, and applying a paint mainly composed of a polymer having low moisture permeability and good adhesion to wood, A water-proofing step of covering with a rubber sheet or film that is hardly permeated, and a pressure-compressing step of guiding the wood after the water-proofing treatment into a liquid and compressing the liquid with a hydrostatic pressure of the liquid in a softened state of the wood; Raising the temperature of the liquid to 140 to 180 ° C. while maintaining the pressure of the liquid to heat the wood in the liquid to fix the compression structure of the wood; And a step of taking out the wood to be taken out of the wood.

[0008]

According to this method, since softened wood is compressed using hydrostatic pressure, a mold is not required, and the work of attaching and detaching wood to and from the mold is eliminated. The cost required for the driving device and the like can also be reduced. Moreover, since the movement of the compressed wood can be performed easily and reliably in still water, the molding operation can be performed efficiently. Further, the damage caused by the contact between the mold and the wood is eliminated, and a molded article having a good appearance can be obtained.

[0009]

FIG. 1 shows an example of a compression molding apparatus for carrying out a first invention and a second invention. The compression molding device 40 includes a pressure-resistant container 41, a heater 42, a water tank 43, and a pump 44. The pressure-resistant container 41 is formed in such a size that logs cut into a predetermined length can be sufficiently arranged. The heater 42 is for heating the liquid filled in the pressure-resistant container 41 and compressed to a predetermined temperature,
It consists of an appropriate band heater and the like. This heater 42
Although not shown, a well-known thermostat or the like may be provided.

Known water tank 43 and pump 44 can be used. The water tank 43 is filled with a liquid such as water or oil as the pressurized medium, and the liquid is introduced into the pressure-resistant container 41 by a pump 44 to increase the pressure in the pressure-resistant container 41. Is available. Although there is no particular limitation on the liquid, water is most preferable in consideration of economy, ease of handling, and the like. In addition, an appropriate aqueous solution, emulsion, oil, or the like can be used depending on the purpose. For example, when heat resistance is required for a wood molded product, a heat resistant liquid is used as a pressurized medium. This heat-resistant liquid has a boiling point of 180 and has no reactivity with the raw wood.
Those which do not thermally decompose above ℃ and have no toxicity are preferable, for example, silicone oil and paraffin.

Reference numeral 45 denotes a drain valve of the pressure-resistant container 41, 46 denotes a pressure relief valve, 46a denotes a relief valve,
Reference numeral 7 denotes a lid, and a pressure-resistant container 4
Seal 1 Reference numeral 49 denotes a cylinder filled with a suitable inert gas such as nitrogen.

As the raw wood 10 used in the present invention, a suitable conifer such as cedar or larch is selected, and a tree obtained by cutting off the branches and leaves is used. The bark may be left as it is or may be peeled off, but it is preferable that the bark has no crack on the surface. The water content of this raw wood is adjusted in advance before compression molding (water content adjusting step).

The water contained in the wood 10 represented by the water content is defined as the water present in the wood structure and bonded to the wood constituents by hydrogen bonding or the like, and the unbound free water. It is. If the free water content is too high, the cells and the space in the vessel will be filled with water, making it substantially difficult to compress by hydrostatic pressure. On the other hand, if the water content is too low, cracks may be generated on the wood surface, and a compression medium described later may penetrate into the wood or impair the appearance of the product. In addition, the softening temperature of the wood rises, making it difficult to compress the wood by hydrostatic pressure. In addition, it requires a lot of energy and time to reduce the water content, and it is difficult to perform molding economically. Occurs. Preferably, it is 10 to 80% near the fiber saturation point of wood. Drying is the most common method of adjusting the moisture content of wood. Various drying methods are known, from a natural drying method in which wood is left in the atmosphere and dried, to a high-temperature drying method in which wood is dried at a temperature of 100 ° C. or higher.
The present invention is not particularly limited.

By the way, depending on the type and shape of the wood used, the pressurizing medium may penetrate into the wood tissue due to the liquid pressure at the time of pressurizing and compressing, which hinders effective compression of the wood. For example, when coniferous wood such as cedar and larch is compressed in water, the moisture at both ends of the wood is insufficiently compressed due to the moisture that penetrates through the inside of the wood.
For this reason, the tip surface is coated with a paint mainly composed of a polymer having low permeability to the moisture and good adhesion to wood, or covered with a rubber sheet or a film that is not easily permeable to water. It is preferable (the wood-mouth surface waterproofing process).

The wood 10 subjected to the waterproofing process is put into the pressure-resistant container 41, a liquid is injected by a pump 44, and the wood 10 is pressurized and compressed by a liquid pressure under the softened state of the wood (pressurizing and compressing step). ).

In order to soften the raw wood, it is necessary to heat the wood at a temperature higher than the softening points of lignin and hemicellulose. The temperature of the softening point depends on the moisture content of the wood, and the softening point of wood containing water at or above the fiber saturation point is generally around 100 ° C. The softening point increases with the decrease.
Therefore, when softening large-diameter wood, it is preferable to heat the wood in hot air containing water vapor close to saturation in order to avoid excessive drying of the surface layer portion for a long-time heating. Also, as in this embodiment, there is a method in which wood is filled in a pressure vessel and filled with liquid, and heated until the wood temperature exceeds the softening point. That is, in the later-described embodiment using the illustrated compression molding apparatus 40, hot water of 95 ° C. is injected into the pressure-resistant container 41 containing the wood 10, and the air in the pressure-resistant container 41 is completely replaced with the liquid. The valve 46b is closed to increase the internal pressure of the pressure-resistant container 41, and the softened wood is pressurized and compressed by the hydrostatic pressure of the liquid. The valve 46b
Is closed, the internal pressure in the pressure-resistant container 41 increases, stabilizes within a certain range for a while, then increases again, and the relief valve 46a operates at the increased internal pressure.

Next, the temperature of the wood 10 is lowered to a temperature lower than its softening temperature while maintaining the fluid pressure in the pressure-resistant container 41, so that the wood can be cooled without using a shaping jig. Fix the compression structure (hydraulic constant temperature lowering step). In the illustrated device 40, the relief valve 4
After the operation of 6a, the pump 44 makes the injection speed of the cold water coincide with the drainage speed of the relief valve 46a, so that the water temperature decreases while the water pressure is kept constant.

After that, the lid 47 is opened and the wood 10 is taken out of the liquid (wood taking-out step). At that time, in the illustrated apparatus 40, after the supply of the cold water is stopped to lower the internal pressure, the wood 10 is taken out. In the obtained compression-molded product, since the wood is shaped only by indirect compression by hydrostatic pressure, rough and soft portions of the wood are compressed, and complicated wrinkles reflecting the fine structure of the wood are formed on the surface. It appeared on the whole and was very highly decorative even as it was, and could be suitably used for pillars between floors and the like.

Further, as shown in the second invention, the water content of the wood is adjusted (moisture content adjusting step), and the wood edge is subjected to waterproof treatment (wood surface waterproofing step). Pressurized and compressed by the hydrostatic pressure of the liquid (pressurized compression process),
By increasing the liquid temperature while maintaining the hydraulic pressure, the compressed structure of the wood is fixed (hydraulic constant liquid temperature raising step), and then the wood is taken out of the liquid (the wood removing step). The compression structure can be fixed. The temperature at which the liquid rises is 140-180 ° C.
As described above, by increasing the liquid temperature while maintaining the compressed state of the wood, hemicellulose and lignin in the wood tissue are hydrolyzed, and the internal stress generated in the tissue by the compression is removed, and the compressed shape of the wood is reduced. Is fixed. The compression-molded product obtained by this method is also excellent in design because, as in the first invention, the wood is shaped only by indirect compression by hydrostatic pressure, so that complicated wrinkles appear on the wood surface. It became.

[0020]

EXAMPLE 1 Next, a concrete example of the present invention will be described. A peeled cedar log (end diameter 15 cm, length 1 m) is sealed with a polyester film having a thickness of 100 μm (micron). Open a pinhole in the film, 11
After drying in a hot air dryer at 0 ° C. for 3 days, the average moisture content was 37%. The wood was taken out of the drier, and a methylene chloride solution of chloroprene (20%) was applied to both mouths of the wood and dried, and covered with a vinylidene chloride film from above, and fixed with a heat-resistant rubber string. Next, before the temperature of the wood was cooled, the wood was put into the compression molding apparatus 40 of FIG. 1 and hot water of 95 ° C. was injected by the pump 44. When the inside air is completely replaced with hot water, the valve 46b is closed and the internal pressure rises at a stretch to 8 to 10 atmospheres, stabilizes within a certain range for a while, then rises again and reaches 30 kg / cm ² , and the relief valve 46a was activated, and thereafter, the cooling water injection speed by the pump 44 coincided with the drainage speed from the relief valve 46a, and the water temperature dropped while the water pressure was kept constant. The water temperature dropped to 32 ° C. 15 minutes after the start of the injection of cold water, and hardly changed thereafter. After 60 minutes, the supply of cold water was stopped, the internal pressure was reduced, and the wood was taken out. The wood was compressed to a cross-sectional area of 50% of the cross-sectional area before compression, and the surface had complicated irregularities, and had an appearance like a cedar drawn log.

[0021]

Example 2 A chloroprene-based wood adhesive was applied to both ends of a cedar log having a diameter of 15 cm, a length of 60 cm and an average moisture content of 25% dried at a temperature of about 100 ° C. in the same manner as in Example 1. After coating and pressing a commercially available polyvinylidene chloride film for food packaging on the coated surface, the film was placed in a compression molding apparatus 40 shown in FIG. 1, the cavity of the container was filled with silicone oil, and a lid was attached. Next, the inside was heated with a band heater 42 to control the temperature at 100 ° C., and then pressurized with a nitrogen cylinder 49 at 15 kg / cm ² . In this state, the wood 10 is further heated by a band heater to 16
The mixture was heated to 0 ° C., held for 60 minutes, and then cooled to room temperature.
The obtained wood was compressed to 52% of the original wood by volume ratio, and the surface exhibited irregular irregularities in the shape of a drawn log as in Example 2. Surface hardness (JIS Z 2101) is 1.5kgf
/ Mm ² , and the disc-shaped sample cut out of the wood showed only a small dimensional change even after being treated for 60 minutes in boiling water.

[0022]

As shown and described above, according to the method for molding wood of the present invention, the compression of the wood utilizes the hydrostatic pressure without using the mold, so that the mold and its driving device are used. It is possible to suppress an increase in equipment cost due to the provision. Also, pressurizing and shape shaping of the wood in the pressure-resistant container not only saves complicated labor and labor for taking the wood in and out of the container, but also prevents the surface of the wood from being damaged by contact with the mold. Since it does not occur, the appearance of the molded product surface can be maintained. Moreover, since the movement of the wood can be easily performed in the liquid, the operation of forming the wood can be performed more easily.

Further, according to the present invention, it was possible to obtain a pillar material having a high-grade appearance suitable between floors. further,
Since a shaping jig is not required, the operation of attaching and detaching the wood to and from the mold and the damage caused by contact between the mold and the wood are eliminated. In addition, the cost required for the mold and its driving device is reduced, so that such a wood forming operation can be performed economically and efficiently.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a compression molding apparatus that performs a molding method of the present invention.

[Explanation of symbols]

 Reference Signs List 10 wood 40 compression molding device 41 pressure-resistant container 42 heater 43 water tank 44 pump 46 pressure release valve 46a relief valve 47 lid 48 clamp

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B27K 1/00-5/06

Claims (2)

(57) [Claims] 1. A water content adjusting step for adjusting the water content of the wood to 10 to 80%, and using a polymer having low moisture permeability and good adhesiveness to the wood with the two lips of the wood whose water content is adjusted. A coating process of applying a paint as a main component, or a waterproofing process to cover the wood with a rubber sheet or film that is hardly permeable to water; Pressurizing and compressing, and a liquid pressure for lowering the temperature of the liquid while maintaining the pressure of the liquid to lower the temperature of the wood in the liquid to a temperature lower than the softening temperature of the wood under the compressed state, thereby fixing the compressed structure of the wood. A method for forming wood, comprising: a step of lowering a constant liquid temperature; and a step of taking out wood from the wood. 2. A water content adjusting step of adjusting the water content of the wood to 10 to 80%, and applying a polymer having low moisture permeability and good adhesiveness to the wood to both mouths of the wood having the adjusted water content. A coating process of applying a paint as a main component or a water-proofing process for covering the wood with a rubber sheet or film that is hardly permeable to water; And a liquid pressure of 140 to 18 while maintaining the pressure of the liquid.
It is characterized by comprising a step of raising the temperature of the wood in the liquid to 0 ° C. to heat the wood in the liquid to fix the compression structure of the wood, and a step of raising the temperature of the liquid at a constant pressure, and a step of removing the wood from the liquid. The method of forming wood.