JP3027828B2 - Building material and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a building material in which a decorative material is adhered to the surface of a wooden material via an adhesive, and a method for producing the same.

[0002]

2. Description of the Related Art Wood materials, especially wood, are used as wall materials, floor boards, ceiling boards, stair steps, stair side plates, shelves, counters, door materials, frame materials, opening members, construction materials and the like. Or a material obtained by attaching a decorative material such as decorative paper or veneer to the surface of a substrate such as a laminated material, a plywood, or a particle board via an adhesive.

[0003] On the other hand, it has been conventionally proposed to condense wooden materials by heating and compressing them. The consolidation by heating and compressing a wooden material according to a conventional method is performed in a state where the wooden material is in a wet state or is humidified in a steam atmosphere so that the wooden material has a high moisture content.

[0004] In this method, the consolidation is carried out by heating and compression at a high water content, that is, in a state where a large amount of water is present in the wood material, so that water is used as a plasticizer, particularly hemicellulose, lignin, etc. Act largely as a plasticizer on the non-crystalline components of
The temperature is reduced to about ℃, and the plasticity of the wood material is increased.

[0005]

In the above-mentioned conventional architectural board, when softwood is used for the substrate, there is a difference in specific gravity between the wood of the spring wood and the wood of the autumn wood. There is a problem that the suction amounts are different, the adhesive strength of the decorative material varies, and the decorative material is likely to wrinkle or swell.

In the case of a hardwood substrate, the conduit groove is large and porous, so that the adhesive is bridging in the conduit groove portion, and conversely, the adhesive is reduced in the conduit groove portion to lower the adhesive force. Occurs, and wrinkles and swelling of the cosmetic material,
There has been a problem that collapse and the like are likely to occur.

Therefore, in order to reduce the difference in specific gravity of the surface of the softwood material or to fill the conduit groove of the hardwood material to make the surface smooth, the surface of the substrate is strengthened and smoothed by a sealer treatment, a filling treatment or the like. After that, an adhesive was applied to apply a cosmetic material.

However, the necessity of the pretreatment before the application of the adhesive as described above complicates the process, and requires strict control of the amount of application and drying. And the cost is increased.

[0009] Further, in the case of a wood material, the dimensional change rate in the width, length and thickness directions accompanying the absorption and release of moisture of the wood itself is large, so that when a decorative material is adhered to the surface via an adhesive, Due to the difference in the moisture absorption between the front and back sides, the balance is lost, and warpage and twisting occur, and wrinkles, swelling, fine cracks, peeling, and the like of the cosmetic material resulting therefrom occur. In order to prevent this, the surface of the wooden material is subjected to a moisture-proofing treatment such as a moisture-proof coating or a moisture-proof sheet attachment. However, as described above, productivity reduction and cost increase due to complication of the process are inevitable. Was.

On the other hand, in the consolidation treatment of the wooden material according to the conventional method, since the wooden material is heated and compressed in a high water content state, the high steam pressure of the water present inside the wooden material is reduced during decompression. It acts as a force for restoring the compacted state, and it is difficult to maintain the compacted state in combination with the springback phenomenon due to the pressure release. In particular, in the case of a wood material having a low specific gravity, puncturing (delamination) may occur due to release of the high steam pressure instantaneously.

In order to prevent the release of a high vapor pressure, it is conceivable to perform cooling in a pressed state, but the productivity is extremely low and the cost is greatly increased.

Further, according to the conventional technique, even if the compacted state can be maintained, the whole wood material in the high water content state is compacted, so that the wood material has a high specific gravity. Would.

[0013]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems of the prior art, and is made by heating and compressing a wooden board whose water content is adjusted to a fiber saturation point or less. An architectural material characterized in that a densified material having a consolidated hard layer formed on both surfaces is used as a base material, and a decorative material is adhered on at least the surface thereof by releasing an adhesive.

[0014]

Further, in the method for producing a building 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 lower than a softening point temperature of cellulose which is a crystalline component of the wood material. And a heat-compressed material at a temperature equal to or higher than the softening point of the adjusted moisture content of the non-crystalline component, and then decompressed and cooled, thereby forming a consolidated material having a hard layer compacted on both front and back surfaces of a wooden material. And applying a cosmetic material to at least the surface of the consolidated material via an adhesive.

As the wood material used as the substrate of the building material of the present invention, a solid wood material, a solid sawn wood material, or a processed material such as a laminated material, a laminated veneer material, a plywood, a particle board, a fiber board or the like is used. As these wood materials, both softwood materials and hardwood materials can be used, and particularly soft materials and low specific gravity materials are suitably 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 referred to herein is preferably 35%
The following moisture content is meant.

The wood material whose moisture content has been adjusted to be below the fiber saturation point is inserted between the hot plates of a hot press apparatus provided with a thickness regulating jig generally called a distance bar for regulating the distance between the upper and lower hot plates. You.

As the thickness regulating jig between the hot plates, a jig having a thickness of 80 to 95%, more preferably 82 to 92% of the thickness of the wooden material is used. In other words, the thickness regulating jig is attached so that the compression ratio of the wooden material is 5 to 20%, more preferably 8 to 18%.

If the compression ratio of the wooden material is less than 5%, the compaction on both the front and back surfaces becomes insufficient, and the strength required for the hard layer cannot be obtained. Conversely, the compression ratio of wood is 20
%, The front and back surfaces are sufficiently densified to obtain the required strength as a hard layer, but the overall specific gravity is increased, resulting in an increase in weight. Is not preferable because the yield decreases and the cost increases.

The compression ratio can be arbitrarily selected within the above range according to the type of wood used, the specific gravity of the wood itself, the surface hardness to be obtained, and the like. Set the control jig.

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

The hot pressing is performed by setting the hot pressing temperature to a temperature equal to or lower than the softening point temperature of cellulose, which is a crystalline component of the wood material, and equal to or higher than the softening point temperature in the adjusted moisture content of the amorphous component. Will be

The pressing time and the pressing pressure are arbitrarily set according to the specific gravity, softness, etc. of the wood material used.
Since the required compression ratio is obtained by using the thickness regulating jig at the time of pressing, the pressing time is 3 to 15 minutes, and the pressing pressure is 5 to 25.
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 device gradually undergoes thermal softening and consolidation due to the pressing force from the front and back surfaces directly in 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 portions of the wood material are compacted. As described above, the temperature of the wood material itself does not increase as a whole even at the time of hot pressing, so that the wood material is easily cooled by the subsequent pressure release. In addition, fibrous cellulose remains in the wood structure without thermal softening, and the hemicellulose and lignin softened and melted at the time of hot pressing act as an adhesive to the cellulose. The springback of the wood material due to the pressure is minimized, and a compacted hard layer is formed on both front and back surfaces.

The hardness of the consolidated hard layer is determined according to JIS Z
4.5k in the method of wood hardness test according to -2007
It is preferably at least gf / mm ² . 3. Hard layer
If it is less than 5 kgf / mm ² , the impact resistance of the surface is insufficient and the surface is apt to be damaged, and the bending strength of the material itself is not improved due to insufficient consolidation, and the hydrophobic property is not improved. In addition, the swelling rate and the water absorption rate cannot be reduced, so that dimensional stabilization cannot be achieved.

Using the thus obtained consolidation material having a hard layer on both front and back surfaces as a base material, an adhesive is applied to at least the surface thereof using a coating device such as a roll coater or a spreader. As the adhesive, a vinyl acetate resin type, a urea resin type, a melamine resin type, a phenol resin type, an acrylic resin type, a urethane resin type, a synthetic resin type adhesive such as isocyanate or a modified adhesive thereof is preferably used. These are used alone or as a mixed adhesive obtained by optionally mixing them. As the adhesive, an adhesive which is transparent or becomes transparent when cured, or a colored adhesive to which a coloring agent is added as necessary is used.

The decorative material is placed on the surface of the base material to which the adhesive is applied, and is pressed by a pressing device such as a laminating device, a vacuum press, a hot press, a cold press, etc., so that the decorative material is adhered. As the decorative material, any material such as a decorative paper, a decorative synthetic resin sheet, a veneer, a veneer provided with a backing material, or the like is used.

If necessary, fine grooves can be formed on the surface hard layer of the substrate by wire brushing, sanding, or the like. Since the fine grooves increase the surface area of the hard layer and also exert an anchoring effect thereby,
The adhesive force of the decorative material provided on the surface of the hard layer is improved.

[0030]

The softening point of cellulose, which is a crystalline component in wood, is 200 to 250 ° C. regardless of the water content of the wood.
However, the softening points of the non-crystalline components hemicellulose and lignin greatly change depending on the moisture content of the wood material, and the softening points of the hemicellulose and lignin in a completely dry state are about 180 ° C. and about 150 ° C., respectively. ° C, but at a water content of 35%, which is the fiber saturation point of the wood material, the softening point temperature drops to around 60 ° C. That is, unlike cellulose which is substantially non-plastic, hemicellulose and lignin are plasticized by the moisture contained in the wood material acting as a plasticizer even at a fiber saturation point or lower.

Therefore, for example, the fiber saturation point 3
In the case of a wood material adjusted to a water content of 5%, by setting the heat pressure temperature in the range of about 60 to about 200 ° C., cellulose as a crystalline component hardly softens and becomes amorphous in tissue cells. Hemicellulose and lignin as components can be heat-softened.

By heating and compressing the woody material having a low water content below the fiber saturation point at such a temperature, only the portions near the front and back of the woody material are compacted to form a hard layer.

A decorative material is stuck on the hard layer via an adhesive to obtain the building material of the present invention.

[0034]

FIG. 1 shows a schematic structure of a building material according to the present invention. Hard layers 2 and 2 are formed on both front and back surfaces of a wooden material as a base material 1 by consolidation, and an adhesive layer 4 is formed on one surface thereof. The decorative material 5 is adhered via the.

As an example of the substrate 1, a thickness of 30 mm,
Agatis solid sawn timber with a width of 150 mm, a length of 100 mm and a specific gravity of about 0.5 was mixed with a low water content below the fiber saturation point (19-
After drying to 21%), it was inserted between the hot plates of a hot press equipped with a 25 mm thickness regulating jig, hot plate temperature 160 ° C., pressing pressure 10 kgf / cm ² , pressing time 15
For 30 minutes, the thickness obtained was 25 mm.
Approximately 8-10m from the front and back of compressed solid wood
a hard layer 2 having a specific gravity of 0.6 to 1.0 in a thickness range of m
No. 2 was formed, and the specific gravity of the inner central portion 3 was almost constant at the whole specific gravity (about 0.5) before the consolidation treatment. Also, the hardness of the hard layer is 4.5~16.5kgf / mm ^2, the pre-consolidation process wood hardness 2.6~3.4kgf / m
m ² was significantly improved.

[0036]

According to the present invention, the hard layer is formed by increasing the specific gravity of only the front and back sides of the wooden material without increasing the overall specific gravity, so that the bending strength, surface smoothness,
Since the surface hardness etc. are improved and the balance between the front and back is maintained, even if a cosmetic material is stuck to only one surface via an adhesive, warpage or twisting may occur. Absent.

The hard layers on the front and back of the wood material as the base material mainly include hemicellulose, which is an amorphous component in the wood material,
Because lignin is formed by being softened and melted and then hardened to a high density after being compressed, it becomes a hydrophobic film and, together with the reduction in hydrophilicity due to compaction, reduces the swelling rate and water absorption rate Can significantly improve the dimensional stability of wood.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Hard layer 3 Central part 4 Adhesive layer 5 Cosmetic material

Claims (4)

(57) [Claims] 1. A heat-compression method for a wood board whose water content is adjusted to a fiber saturation point or lower, wherein a hardened material having a hardened layer formed on both front and back surfaces is used as a base material, and an adhesive is applied on at least the surface thereof. An architectural material characterized in that a decorative material is stuck thereon. 2. The hardness of the hard layer is 4.5 kgf / mm 2.
The building material according to claim 1, wherein: 3. A wood board whose moisture content is adjusted to a fiber saturation point or lower is sandwiched between hot plates, and the adjusted water content of the amorphous component is lower than the softening point of cellulose which is a crystalline component of the wood board. By heating and compressing at a temperature equal to or higher than the softening point temperature, and then decompressed and cooled, a consolidated material having a consolidated hard layer on both the front and back surfaces of the wooden board is obtained, and at least the surface of the consolidated material is obtained. A method for producing a building material, comprising: attaching a decorative material to the surface of the building via an adhesive. 4. The method for manufacturing a building material according to claim 3, wherein after forming fine grooves on the surface of the hard layer of the consolidated material, the decorative material is attached via the adhesive.