JPH09155818A - High-density ligneous material and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-density ligneous material which is excellent in bend strength, surface properties, and dimensional stability in spite of its lightness in weight and does not generate warps and torsions by heightening specific gravities of only top and rear faces without heightening the whole specific gravity of a base material so as to form hard layers on the top and rear faces. SOLUTION: A ligneous material whose water content is adjusted to a fiber saturation point or below is pinched in between hot plates, heated and compressed at a temperature below a softening point temperature of a cellulose as a crystal component of the ligneous material and above a softening point temperature in water content after adjustment of a non-crystal component. Thereafter, the compression is released and cooled, so that a ligneous material having densified hard layers 2 on the top and rear faces of the ligneous material is obtained. A butt end edge of the high-density ligneous material 1 is waterproofed. The waterproofing can be performed by sticking an edge sticking material 5 to the but end edge or by impregnating the butt end edge with a synthetic resin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a compressed wood material and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, it has been proposed to heat-compress and consolidate wood materials. The consolidation of wood materials by heating and compression according to the conventional method is performed in a wet state of the wood materials or by humidifying them in a steam atmosphere so that the wood materials have a high water content.

[0003] In this method, since the compaction is carried out by heating and compression at a high water content, that is, in the presence of a large amount of water in the wood material, the water is a plasticizer, particularly hemicellulose, lignin, etc. in the main components of wood. It has a great effect as a plasticizer on the non-crystalline components of and has a softening point of 60
It lowers the temperature to about 0 ° C and increases the plasticity of the wood material.

[0004]

However, in the consolidation treatment of a wood material by the above-mentioned conventional method, since the wood material is heated and compressed in a high water content state, a high water vapor content of the wood material is present. When the pressure is released, it works as a force to restore the consolidated state, and it is difficult to maintain the consolidated state together with the springback phenomenon due to the release. Further, particularly in a wood material having a low specific gravity, the high steam pressure may be released in an instant, so that puncture (delamination) may occur.

In order to prevent the release of the high vapor pressure, it is possible to cool in the compressed state, but the productivity is extremely low and the cost is greatly increased.

Further, according to the above-mentioned prior art, even if the compacted state can be maintained, since the entire wooden material having a high water content is compacted, it becomes a high specific gravity wooden material. Will end up.

[0007]

SUMMARY OF THE INVENTION The present invention was devised with the object of solving the problems of the prior art described above, and hard layers hardened on both front and back sides by heating and compressing a wood material. Is formed, and the wood edge is subjected to waterproof treatment, which is a compressed wood material.

In the compressed wood material according to the present invention, a hardened layer is formed on both front and back surfaces by heat compression of the wood material whose water content is adjusted to the fiber saturation point or less, and the wood rim is waterproofed. It is characterized by being done.

In these compressed wood materials, the wood rim may be impregnated with a synthetic resin. Further, an edge attaching material may be attached to the edge of the wood opening.

In the method for producing a compressed wood material according to the present invention, a wood material having a water content adjusted to a fiber saturation point or lower is sandwiched between hot plates and the temperature is not higher than the softening point temperature of cellulose which is a crystalline component of the wood material. And and heat-compressed at a temperature equal to or higher than the softening point temperature in the water content of the amorphous component after the adjustment, then decompressing, by cooling, to form a consolidated hard layer on both the front and back surfaces of the wood material, The feature is that the edge of the wood is waterproofed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As the wood material used as the compressed wood material of the present invention, solid wood, solid sawn wood, laminated wood, laminated veneer wood, plywood, particle board, fiber board, and other processed materials can be used. Used. As the wood materials, both softwood materials and hardwood materials can be used, and particularly soft materials and materials with low specific gravity are preferably used.

These wood materials are dried before or after sawing to adjust the water content below the fiber saturation point. The water content below the fiber saturation point here is preferably 35%.
The following water contents are meant.

The wood material whose water content is adjusted to be below the fiber saturation point is inserted between the hot plates of a hot press machine to which a thickness control jig generally called a distance bar for controlling the distance between the upper and lower hot plates is attached. It

As the thickness control jig between the heating plates, a jig having a thickness of 60 to 95%, more preferably 65 to 92% of the thickness of the wood material is used. In other words, the thickness regulating jig is attached so that the compressibility of the wood material is 5 to 40%, more preferably 8 to 35%.

If the compressibility of the wood material is less than 5%, compaction on both the front and back surfaces becomes insufficient, and the strength required for the hard layer cannot be obtained. Conversely, the compressibility of wood is 40
%, The front and back surfaces will be sufficiently consolidated to obtain the required strength as a hard layer, but the overall specific gravity will increase, leading to an increase in weight, and giving an excessive compression rate is a loss of raw material. Is large, the yield is reduced, which causes an increase in cost, which is not preferable.

The compressibility can be arbitrarily selected within the above range depending on the wood species used, the specific gravity of the wood itself, the surface hardness to be obtained, etc., and the thickness corresponding to the compressibility. Set the control jig.

The wood material inserted between the upper and lower hot plates of the hot press machine to which the thickness control jig is attached is heated and compressed by hot pressing, and is hardened on both front and back surfaces to form a hard layer.

The hot pressing is carried out at a hot pressing temperature which is equal to or lower than the softening point temperature of cellulose which is a crystalline component of the wood material and which is equal to or higher than the softening point temperature of the amorphous component in the adjusted water content. Be seen.

The pressing time and the pressing pressure are arbitrarily set according to the specific gravity, softness, etc. of the wood material used,
Since the above-mentioned thickness regulating jig is used to obtain the required compression rate during pressing, the pressing time is 3 to 15 minutes and the pressing pressure is 5 to 25 minutes.
It is preferably set to kg / cm ² .

The wood material heated and compressed between the upper and lower hot plates of the hot press machine is gradually softened and compacted by the pressing force from the front and back surfaces that are in direct contact with the hot plate toward the center. Since the water content is adjusted to a low water content below the fiber saturation point, heat transfer is relatively slow, and only the front and back parts of the wood material are consolidated. In this way, the temperature of the wood material itself does not rise even during hot pressing, so that the wood material is easily cooled by subsequent decompression. Moreover, the fibrous cellulose remains in the wood tissue without being softened by heat, and the softened and melted hemicellulose and lignin act as an adhesive to the cellulose when heated and pressed, so that the solution after hot pressing and pressing Springback of the wood material due to the pressure is minimized, and consolidated hard layers are formed on both front and back surfaces.

The hardness of the hardened layer is JIS Z
-1.5k in the hardness test method of wood according to 2007
It is preferably gf / mm ² or more. Hard layer is 1.
If it is less than 5 kgf / mm ² , the impact resistance of the surface is insufficient and scratches are likely to occur, and since the compaction is insufficient, the bending strength of the material itself is not improved and the material is hydrophobic. Since the swelling rate and the water absorption rate cannot be reduced, dimensional stabilization cannot be achieved.

The thus-obtained edges of the compacted material having hard layers on both front and back sides are waterproofed. This waterproofing process can be performed by impregnating the edge of the wood with a synthetic resin. That is, a synthetic resin paint such as an acrylic resin-based, urethane resin-based, epoxy resin-based, vinyl chloride resin-based, or phenol resin-based resin is applied and impregnated on the edge of the wood and dried. Not only impregnation, but a film made of the synthetic resin may be formed on the edge of the wood.

Alternatively, waterproofing can be carried out by attaching an edge attaching material to the edge of the compacted material.
That is, a synthetic resin sheet, a synthetic resin plate, a metal sheet,
An edge attaching material such as a metal plate, a synthetic resin reinforced paper, a synthetic resin reinforced single plate, or the like is attached to the edge of the mouthpiece through an adhesive or by heat fusion.

A decorative layer is formed on the surface of the compacted material by pattern printing or color coating, or by adhering a decorative material such as a decorative paper, a synthetic resin sheet for a decorative sheet, or a veneer to the surface of the consolidated material. To be done.

The softening point temperature of cellulose, which is a crystalline component in wood, is 200 to 25 regardless of the water content of wood.
Although it is almost constant at 0 ° C, the softening point temperatures of non-crystalline components, hemicellulose and lignin, vary greatly depending on the water content of wood, and the softening point temperatures of hemicellulose and lignin in an absolutely dry state are about 180 ° C, respectively. About 150 ℃
However, at a water content of 35%, which is the fiber saturation point of wood, the softening point temperature decreases to around 60 ° C.
That is, unlike cellulose, which is substantially non-plastic, hemicellulose and lignin are plasticized by the water contained in the wood material acting as a plasticizer even at a fiber saturation point or lower.

Therefore, for example, the fiber saturation point of 3
In the case of the wood material adjusted to have a water content of 5%, the heat-pressing temperature in the range of about 60 to about 200 ° C. causes the cellulose, which is a crystalline component, to be hardly softened and to be amorphous in the tissue cells. The components hemicellulose and lignin can be heat-softened.

By heating and compressing a wood material having a low water content below the fiber saturation point at such a temperature, only a portion near the front and back of the wood material is consolidated to form a hard layer.

The compressed wood material of the present invention is obtained by subjecting the obtained wood edge of the consolidated material to waterproofing treatment such as impregnation with a synthetic resin or attachment of an edge bonding material.

FIG. 1 shows a schematic structure of a compressed wood material according to the present invention. Hard woods 2, 2 are formed on both front and back surfaces of a wood material as a base material 1 by consolidation, and a decorative layer 4 is formed on one surface thereof. Is formed, and the edge pasting material 5 is attached to both edges of the mouth.

As an example of the substrate 1, a thickness of 30 mm,
Width 150 mm, length 100 mm, overall specific gravity of about 0.5 solid Agatisu sawwood, low water content below the fiber saturation point (19 ~
21%) and then inserted between the hot plates of a hot press machine equipped with a thickness control jig of 25 mm, the hot plate temperature of 160 ° C., the pressing pressure of 20 kgf / cm ² , and the pressing time of 5 minutes. After heating and pressing at 25m, the obtained thickness is 25m.
Hard layers 2 and 2 having a specific gravity of 0.6 to 1.0 are formed in the thickness range of about 4 to 5 mm from the front and back surfaces of the compressed solid wood of m, respectively, and the specific gravity of the inner central portion 3 thereof is before the consolidation treatment. The overall specific gravity of (about 0.5) was almost constant. Also,
The hardness of the hard layer is 1.5 to 3.6 kgf / mm ² ,
The hardness was remarkably improved as compared with the material hardness before the consolidation treatment of 0.8 to 1.1 kgf / mm ² .

[0031]

According to the present invention, the hard layer is formed by increasing the specific gravity of only the front and back of the wood material without increasing the overall specific gravity.
Since the surface hardness is improved and the balance between the front and back is maintained, even if the decorative layer and the abrasion-resistant coating layer are formed on only one surface, warping or twisting can occur. Absent.

Further, the hard layers on the front and back of the wood material are mainly formed by the amorphous components in the wood material such as hemicellulose and lignin, which are once softened and melted and then hardened to a high density. It becomes a hydrophobic film, and the swelling rate and water absorption rate can be reduced together with the reduction in hydrophilicity due to consolidation. Furthermore, in the present invention, since the wood mouth edge is waterproofed, the strength of the wood edge can be improved and at the same time water absorption from the wood edge can be prevented and the dimensional stability can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a compressed wood material according to the present invention.

[Explanation of symbols]

 1 Base Material (Compressed Wood) 2 Hard Layer 3 Center Part 4 Decorative Layer 5 Edge Adhesive Material

Claims (5)

[Claims] 1. A compressed wood material, characterized in that by heating and compressing the wood material, consolidated hard layers are formed on both front and back surfaces, and the wood rim is waterproofed. 2. A compacted hard layer is formed on both front and back surfaces by heat compression of a wood material whose water content is adjusted to a fiber saturation point or lower, and waterproof treatment is applied to the edges of the wood. Wood material. 3. The compressed wood material according to claim 1, wherein the wood rim is impregnated with a synthetic resin. 4. The compressed wood material according to claim 1 or 2, wherein an edge pasting material is attached to the edge of the wood opening. 5. A water content of a wood material, the water content of which is adjusted to a fiber saturation point or less, is sandwiched between hot plates so that the water content of the wood material is equal to or lower than the softening point temperature of cellulose, which is a crystalline component of the wood material, and the amorphous component is adjusted. Heat-compressed at a temperature above the softening point temperature, then decompressed and cooled to form consolidated hard layers on both front and back sides of the wood material, and the wood edge is waterproofed. And a method for manufacturing a compressed wood material.