JP2022131290A - Laminated plasticity lumber - Google Patents

Abstract

To provide laminated plasticity lumber allowing breaks such as cracks and fissures to be suppressed even when there are some knots and good design to be secured to allow material with knots to be utilized.SOLUTION: Laminated plasticity lumber LPW formed by integrally bonded three or more pieces of lumber NW through laminating them vertical to a grain length direction and a consolidation process heating and pressing in a direction vertical to the grain length direction is provided with: two pieces of decoration material PWD1,PWD2 on a front and a rear layer which are made under high compression by heating to be thin in thicknesses; and one or more pieces of inner layer material PWI arranged between two pieces of the front and the rear decoration material PWD1,PWD2 made by low compression with thickness thicker than those of the decoration material PWD1,PWD2.SELECTED DRAWING: Figure 1

Description

In the present invention, for example, a laminated lumber made by laminating a plurality of soft lumbers such as cypress and cedar is subjected to compaction by applying a compressive force in a direction perpendicular to the length direction of the wood grain, and The present invention relates to a laminated plastic-processed lumber that is integrally joined, and particularly to a laminated plastic-processed lumber that can increase the mechanical strength without causing cracks, fissures, etc., even when knots are present. .

In recent years, the problem of global warming, that is, the increase in the amount of carbon dioxide, which is a greenhouse gas, has become a concern, and wood is expected to absorb and fix carbon dioxide, so wood is used for buildings and furniture. It is said that this will promote deforestation and circulation of forests, thereby contributing to the prevention of global warming. For example, the Ministry of Education, Culture, Sports, Science and Technology (MEXT) recommends using local materials for school furniture such as children's desks. In particular, if domestically produced wood or local wood is used, the amount of carbon dioxide generated during transportation can be reduced, leading to the conservation of domestic forests.

Here, about 40% of the forests in Japan are artificial forests, of which conifers such as cedar and cypress account for more than half. The wood is relatively stable and easy to obtain.
However, conifers such as Japanese cedar and Japanese cypress are soft and have low strength and hardness.

On the other hand, Japan imports a lot of timber from foreign countries, and the demand for domestic timber has fallen sharply. There is a status quo. Forest care, for example, if pruning is not done at the right time, the tree will sprout and become knotty. In particular, conifers such as cedar and cypress have more knots than broad-leaved trees that have been used for conventional plywood.

Therefore, when using domestic wood or local wood, it is preferable to be able to use materials with knots from the cost point of view. That is, materials with few knots are obtained from trees that have been pruned or otherwise trimmed to produce them, and wood with few knots is generally obtained from logs such as side boards that have been removed from posts. Since it can only be collected from a part of the forest, it is a valuable and high-value-added material, and is inevitably expensive. In particular, in light of the current situation where forests that are under-maintained are increasing, it is predicted that the price of materials with few knots will rise further in the future. On the other hand, materials with knots can be procured inexpensively. Therefore, there is a demand for effective utilization of knotted materials.
However, materials with knots tend to have twisted or bent fibers running around the knots, and therefore have problems of poor workability and inferior strength compared to materials with few knots.

Here, as disclosed in Patent Document 1, the present inventors have previously established a technology that can improve the strength characteristics of even soft wood such as cedar by compressing it to increase its density. is doing.
In Patent Document 1, by heating and compressing a piece of wood in a direction perpendicular to the length direction of the wood grain to compress the density distribution of the entire thickness to a predetermined value, even if there are knots, cracks (cracks, fissures) It discloses the technology to make wood without wood.

Japanese Patent No. 6450489

However, depending on the degree of knots, the product of plastically processed lumber with knots that have been subjected to compaction in Patent Document 1 may not be aesthetically pleasing to users because knots appear on the outer surface. Especially in furniture with a small wooden area, the presence of knots can be a decisive factor in purchasing because the position, shade, pattern, etc. of the knots greatly affect the design and aesthetics of the wood product. For this reason, there has been a demand for a product that does not stand out even if wood with knots is used.
In addition, in the technique of Patent Document 1, a single thick piece of wood is compacted and commercialized as a flooring material, etc., and since the lumber is thick, when using a material with knots, During the drying process, knot cracks and knot dropouts may occur, making it difficult to ensure a high yield.

Therefore, the present invention provides a laminated plastically processed lumber that is resistant to cracks, fissures, etc., even if the lumber has knots, can achieve both designability, and can effectively utilize materials with knots. The challenge is to provide

The laminated plastically processed lumber of claim 1 is obtained by laminating three or more lumbers in a direction perpendicular to the length direction of the wood grain, and heating and compressing the lumber in a direction perpendicular to the length direction of the wood grain. A laminated plastic-processed lumber obtained by consolidating and integrally joining two design materials of front and back layers that are highly compressed by the heat compression and have a high density and a thin thickness, and two sheets of the front and back layers. and one or more inner layer materials having a low density and a thickness, which are sandwiched between the design materials and have a lower compression than the design materials.

Here, the three or more pieces of wood are laminated in the direction perpendicular to the length direction of the wood grain, subjected to compression processing by heat compression in the direction perpendicular to the length direction of the wood grain, and integrally joined. Ternaru is a laminated material made by stacking three or more pieces of wood in the direction perpendicular to the length direction of the wood grain. It means that it is a product obtained by compression molding and consolidation processing, and by applying adhesive etc. between the woods in advance and laminating the laminated material, heat compressing and consolidating the adhesive simultaneously with the heat compression of the consolidation processing. It may be one in which the laminated woods are joined together by curing or the like. A laminated material formed by laminating wood without any intervening material may be heat-compressed and compacted, and then integrally laminated and adhered. Note that the above-mentioned lamination in a direction perpendicular to the length direction of the wood grain means lamination on a surface perpendicular to the length direction of the wood grain, that is, on a surface other than the end surface and the end surface, and the number of layers is 3. The number of sheets may be at least as long as it is an odd number or an even number.

In addition, the heat compression in the direction perpendicular to the length direction of the wood grain (tree direction, tree direction) refers to the direction of the fiber of the annual ring It means that the area of the butt end surface of the wood is reduced by heat compression by applying an external force using a press or the like in the direction perpendicular to the direction of the tree. Normally, in the case of cross-grain lumber, considering the amount of strain due to compression, the area of the butt end surface of the wood is reduced by applying press compression to the cross-grain side of the wood. It is also possible to determine whether to press-compress the surface side or the straight-grained surface side, depending on the type of lumber or the like.

The cross-grain surface is a wood surface cut in the longitudinal direction of the wood grain, that is, parallel to the fiber direction of the annual ring and cut in the tangential direction of the annual ring line. In addition, the above-mentioned wood surface is a surface cut in a direction crossing the fiber direction of the annual rings of the wood, that is, a surface cut perpendicularly or obliquely to the length direction of the grain of the wood. is. Further, the straight-grained surface is a wood surface cut in the radial direction (radial direction) of the annual ring line parallel to the fiber direction of the annual rings of the wood. In addition, the above-mentioned oisama (also referred to as nagashisama or hansama) is an intermediate wood grain or wood grain between straight grain and cross grain.

The two design materials are the outer layers of the front and back of the wood that is laminated and joined, that is, the two woods of the surface layer and the back layer, and both are highly compressed than the inner layer material interposed between the design materials. In other words, the amount of compressive deformation of the cells is large and the density is increased. .
The one or more inner layer materials are interposed between the two design materials, which are the surface layer and the back layer, of the laminated and joined wood, and are compressed lower than the design materials, so that the amount of compressive deformation of the cells is small. It has a low density and a large thickness. The inner layer material may be one, or a plurality of two or more, preferably one to three. Determined by the type of wood, etc.

The design material and the inner layer material are laminated and joined in the order of one design material, one or more inner layer materials, and the other design material in the direction perpendicular to the length direction of the wood grain. Boundaries of wood from each other can be distinguished from each other by fine quality lines or by changes in tree ring lines on the butt surface. The design material and the inner layer material are laminated in the thickness direction that is perpendicular to the length direction of the grain of each wood, that is, in the surface other than the end surface and the end surface, and the design of the front and back layers Regarding the material, it does not specify the usage direction of the front and back surfaces. Moreover, the design material and the inner layer material may be laminated with the length of the wood grain matched with each other, or may be laminated in a direction orthogonal to the length direction of the wood grain. Furthermore, it does not matter whether or not each piece of wood has knots, and naturally even wood without knots can be used.
Here, the above-mentioned thickness means the thickness in the direction perpendicular to the grain length direction of the wood, and since there may be cases where the joint surfaces are not uniform at places where the difference in specific gravity between the facing woods is large, the average thickness is used. be compared with In the laminated plastic processed lumber, the front and back surfaces are usually cut after consolidation in order to ensure smoothness, so this corresponds to the thickness after cutting.

The species of wood is not particularly limited, and may be either a coniferous tree or a broadleaf tree. For example, cedar, cypress, pine (larch, Sakhalin fir, Ezo spruce, Japanese red pine, etc.), Japanese sawara, walnut (walnut), yellow poplar, Italian poplar, mominoki, hemlock, spruce, yew, asunaro, paulownia, hiba, birch, itajii, karin , falcata, gmelina, chinaberry, tulip tree, etc. are used. In particular, Japanese cedar and cypress wood are widely distributed in Japan, and thinned wood can be easily obtained in large quantities, so that they can contribute to environmental conservation. In addition, cedar and cypress, which are conifers, have a high porosity in the wood structure, so the thermal conductivity is low, and the warmth is strongly felt when touched.

The design material and the inner layer material of the laminated plastically worked lumber of the invention of claim 2 are laminated with the length direction of the wood grain aligned with each other.

Each of the design materials of the laminated plastically processed lumber of the invention of claim 3 has a pressed surface on the cross-grain surface or chamfered surface on the surface side of the wood.
The above-mentioned cross-grain surface or chamfered surface on the wood surface side means that the cross-grain surface or chamfered surface on the wood surface side is positioned on the front and back surfaces of the heat-compressed laminated plastic processed lumber. That is, the laminated wood is arranged so that the cross grain surface or the chamfered surface on the front side of the wood is positioned on the front and back surfaces, and the press machine that heats and compresses is in contact with the cross grain surface or the chamfered surface on the wood surface side. It means that it was pressed from the cross grain side or the straight side of the wood front side. In addition, the "wood surface" refers to the cross-grain surface or the oishaku surface closer to the bark when viewed from the butt end surface. In addition, the side of the tree that is closer to the core, the center of the annual rings on the opposite side of the tree surface, is called the "back of the tree."

The laminated plastic processed lumber of the invention of claim 4 has an air-dried specific gravity of 1.2 times or more and 1.7 times or less, preferably 1.3 times or more and 1.6 times that of the original wood. It is within the following range.
The above-mentioned air-dried specific gravity is the specific gravity when the wood is dried in the air, that is, when it reaches the air-dried moisture content, and is usually expressed by the specific gravity when the moisture content is 15%. It is a value that compares the weight of the same volume of water with the weight of the water. A larger number means heavier, and a smaller number means lighter.

The design material and the inner layer material of the laminated plastic processed lumber of the invention of claim 5 are the growth rings on the acute angle side where the annual ring line appearing on the butt surface of each of the design materials intersects with the cross grain surface or the chamfer surface on the back side of the tree. The angle θ _D and the annual ring angle θ _I on the acute angle side where the tree ring line appearing on the butt surface of the inner layer timber or two or more inner layer timbers and the cross grain surface or the straight surface of the back side of the tree intersect. , θ _D <θ _I .
The tree-ring line on the butt surface means a linear portion in which the texture is densely formed when viewed from the butt surface, and is a wood grain appearing on the butt surface.
Here, wood is a natural product, and especially when knots are present, the flow of tree ring lines on the butt surface does not necessarily become regular. It is not required that the annual ring angles θ _D , θ _I , which are the crossing angles with the cross-grain surface or the straight surface, satisfy θ _D < θ _I , and the annual ring angles θ _D , θ of the plurality of tree-ring lines of the butt surface are not required. It suffices if the average of _I satisfies θ _D <θ _I .

In each of the design materials of the laminated plastic processed lumber of the invention of claim 6, the annual ring angle θ _D on the acute angle side where the growth ring line appearing on the butt end surface and the cross grain surface or the straight surface on the back side of the tree intersect is 0°<θ _D≤30 °, preferably 0°<θ _I ≤25° Alternatively, the angle θ _I on the acute angle side where it intersects with the chamfered surface is 5°≦θ _I ≦80°, preferably 10°≦θ _I ≦70°.
Here, wood is a natural product, and especially when knots are present, the flow of tree ring lines on the butt surface does not necessarily become regular. It is not required that all of the tree-ring angles θ _D and θ _I , which are the crossing angles with the cross-grain surface or the _chamfering surface, are within the range of the above numerical values. It is sufficient if the average of θ _I is within the above numerical range.

Each of the design materials of the laminated plastically processed lumber of the invention of claim 7 has a thickness of 0.3 to 0.8 times the thickness of the one inner layer material or two or more inner layer materials, Preferably, it is within the range of 0.4 times to 0.6 times.
The above thickness is the average thickness because there are cases where the heating and compression are not necessarily uniform at a location where the specific gravity difference between the facing woods is large.

The laminated plastically processed lumber of the invention of claim 8 has an overall thickness of 15 mm or more and 40 mm or less, preferably 18 mm or more and 35 mm or less, and each design material has a thickness of 1.5 mm or more and 10 mm. Below, it is preferably in the range of 1.5 mm or more and 8 mm or less, and the thickness of the one inner layer material or each of the two or more inner layer materials is 6 mm or more and 15 mm or less, preferably 8 mm or more and 13 mm or less. is within the range of
Note that the above thickness may not necessarily be uniform at locations where there is a large difference in specific gravity between facing wood pieces, so the thickness is taken as an average thickness.

The laminated plastically worked lumber of the ninth aspect of the invention has a Brinell hardness of 15N or more and 30N or less, preferably 18N or more and 30N or less, more preferably 18N or more and 25N or less.
The Brinell hardness (HB) conforms to the wood test method of JIS Z 2101, and a steel ball with a diameter of 10 mm is cast from one design material side of the laminated plastic processed wood at a speed of 0.5 mm per minute to a depth of about 0. .32 (1/π) mm is obtained by dividing the indentation load by the surface area of the dent remaining after the load is removed. Note that wood is a natural product, and since there is a difference in hardness between early wood and late wood, the average of measurements at 12 arbitrary locations is used here.

Each of the design materials of the laminated plastically processed lumber of the invention of claim 10 has a compressibility of 45% to 65%, preferably 50% to 60%, relative to the air-dry specific gravity of the original lumber by the heat compression. The compressibility is 15% to 42%, preferably 20 to 40%, with respect to the air dry specific gravity of the original wood by the heat compression of the one inner layer material or the two or more inner layer materials. The compression rate is within the range.
Here, the compression rate with respect to the air-dried specific gravity of the original wood is calculated from the air-dried specific gravity of the original wood and the air-dried specific gravity of each design material and inner layer material, and is obtained from the following formula. It is a thing.
Compression ratio <%>
= [1-[(air-dried specific gravity of original wood) / (air-dried specific gravity of design material or inner layer material)]]
×100
The air-dried specific gravities of the design material and the inner layer material can be measured by cutting off the individual lumbers of the design material and the inner layer material that are joined to each other at their joint surfaces.

In one or more of the facing surfaces of the design material and the inner layer material of the laminated plastic-processed lumber of the invention of claim 11, there is a convex portion formed by a knot and a concave portion deformed by pressing by the knot. It has a joint surface.
The joint surface formed by the convex portion formed by the knot portion and the concave portion deformed by the pressure applied by the knot portion means a joint surface having undulations in the joint between the pieces of wood. That is, when heated and compressed, the hard knot of one piece of wood presses the opposing portion of the other piece of wood stacked thereon and is deformed, thereby forming a convex portion and knot portion on the joint surface between the joined pieces of wood. It means that there are undulations that are formed by facing the recessed parts formed by deformation pushed into the wood. do.

The laminated plastic processed lumber according to the invention of claim 1 is a laminated lumber obtained by laminating a plurality of lumbers in a direction perpendicular to the length direction of the grain of the lumber. Two design materials having a large amount of compression by the heat compression and a small thickness are arranged on the front and back layers, and the two sheets of the front and back layers are arranged. One or more inner layer materials having a smaller compression amount and a greater thickness than the design material are disposed between the two design materials.

According to the laminated plastically processed lumber of the invention of claim 1, while the design materials forming the front and back design surfaces are highly compressed, the inner layer material interposed between the design materials is plastically processed with low compression. In addition to being able to increase the mechanical strength and surface hardness compared to the wood of the front and back, the inner layer material interposed between the front and back design materials has a lower compression than the design material. By balancing the compressibility, strain due to compression is less likely to occur, so even if a material with knots is used, a strong compressive force is less likely to be applied to the knots. In particular, it is a plastic processing of laminated wood, and even if the wood has knots and there are hard parts with different specific gravities, the hard knots with high specific gravities cannot be obtained by stacking the wood and compressing it under heat. However, the low specific gravity part of the wood layered on it is softened by heat compression and deformed by the pressure of the hard knots, so that the movement of the knots is not restricted, so excessive compressive stress and internal stress are difficult to apply to the knots. . Therefore, even if there are knots, cracks, fissures, and the like are less likely to occur. In addition, since it is made by laminating and joining multiple pieces of wood, even if a material with knots is used for the inner layer material or one of the design materials, it can be used if a material without knots is used for the other design material, which is the surface to be used. In terms of surface design, it is also possible to maintain design.

In addition, according to the laminated plastically processed lumber of the invention of claim 1, a plurality of lumbers are laminated, joined and consolidated to produce a single thickness, and the thickness of each lumber of the raw material is thin. Therefore, it is possible to shorten the drying time in the drying process before consolidation and reduce the drying load. Therefore, even when a material having knots is used, it is possible to prevent knot cracking and knot dropout due to drying, thereby improving the yield.

In this way, according to the laminated plastically processed lumber of the invention of claim 1, even if the lumber has knots, it is difficult to cause cracks such as cracks, cracks, etc. It can be utilized.

According to the laminated plastic processed lumber according to the second aspect of the invention, since the design material and the inner layer material are laminated with the wood grain length direction aligned with each other, when using a material with knots However, the knots tend to press against the laminated wood structure of the opposing material during heat compression, and compressive stress is less likely to be applied to the knots. Therefore, even if there are many knots, knots penetrating the front and back of the wood, or knots with a diameter of 20 mm or more, cracks and cracks at the knots and their surroundings are unlikely to occur. It is. Therefore, in addition to the effect described in claim 1, it is possible to further improve the yield of plastic working.

According to the laminated plastic processed lumber according to the invention of claim 3, each of the design materials has a press surface on the cross grain surface or the chamfered surface side of the wood front side, so the amount of strain due to compression and the internal resistance are reduced. Compressed in the direction of less compression. In addition, the anisotropy of shrinkage is balanced because the cross-grained surface or chamfered surface on the front side of each design material is placed on the front and back surfaces of the laminated plastic processed lumber. Therefore, in addition to the effects described in claim 1 or claim 2, internal cracks and distortions of wood are less likely to occur, and dimensional shape stability is also high.

According to the laminated plastic processed lumber according to the invention of claim 4, the air-dried specific gravity thereof is 1.2 times or more and 1.7 times or less that of the original lumber. In addition to the effect described in any one of 1. above, it is possible to achieve both surface hardness, strength and lightness.

According to the laminated plastically processed lumber according to the invention of claim 5, the design material and the inner layer material are formed at an acute angle where the annual ring line appearing on the butt surface of the design material and the cross grain surface or the chamfer surface on the back side of the tree intersect. and the tree ring angle θ _I on the acute angle side where the tree ring line appearing on the butt surface of the inner layer material intersects with the cross grain surface or the _{straight surface of the back side of the tree, θ D <} θ _I. . When the design material and the inner layer material have a relationship of θ _D <θ _I in annual ring angle, the amount of compressive deformation of the design material is large, and internal stress is less likely to occur during heat compression. Therefore, in addition to the effect described in any one of claims 1 to 4, it is possible to increase the surface hardness without causing cracks, fissures, and other fractures even if there are knots.

According to the laminated plastic processed lumber according to the invention of claim 6, the design material has an annual ring angle θ _D of 0 on the acute angle side where the annual ring line appearing on the butt end surface intersects with the cross grain surface or the chamfer surface of the back side of the tree. ° < θ _D ≤ 30°, and in the inner layer material, the angle θ _I on the acute angle side where the annual ring line appearing on the butt surface intersects with the cross grain surface or the straight surface of the back side of the tree is 5° ≤ θ _I ≤ Since the angle is 80°, the buckling deformation of annual rings during heat compression is small. Therefore, even if knots are present, cracks are unlikely to occur inside the lumber, and distortion and the like are unlikely to occur. Therefore, in addition to the effect described in any one of claims 1 to 5, it is possible to stabilize the quality.

According to the laminated plastic-processed lumber according to the seventh aspect of the invention, each of the design materials has a thickness of 0.3 to 0.3 to the thickness of the inner layer material or each of the inner layer materials of two or more sheets. It is within the range of 8 times. If the thickness of the design material is within the range of 0.3 to 0.8 times the thickness of the inner layer material even after compression processing, the inner layer material superimposed on the design material on the use side has knots. Even in such a case, the thickness is such that the knots and darkened and blackened patterns around the knots do not appear on the design material to be used, and the surface hardness can be increased. Therefore, in addition to the effect described in any one of claims 1 to 6, it is possible to achieve both surface strength, hardness, and surface design.

According to the laminated plastic-worked lumber according to the eighth aspect of the invention, the total thickness of the laminated plastic-worked lumber is within a range of 15 mm or more and 40 mm or less, and the thickness of each design material is 1.5 mm or more, The thickness of the inner layer material is within the range of 10 mm or less, and the thickness of the one inner layer material or each of the two or more inner layer materials is within the range of 6 mm or more and 15 mm or less, so the inner layer material overlaid on the design material on the use side Even if there is a knot, the thickness is such that the knot and the darkened and blackened pattern around the knot do not appear on the design material on the side of use, and the overall thickness is thin and lightweight, but the surface hardness is ensured. Therefore, in addition to the effect described in any one of claims 1 to 7, surface hardness/strength, surface design and lightness can be achieved at the same time.

According to the laminated plastically processed lumber according to the ninth aspect of the invention, since the Brinell hardness is in the range of 15 N or more and 30 N or less, the surface hardness is such that shallow and fine scratches due to writing, cutting, etc. are unlikely to occur. Therefore, in addition to the effect described in any one of claims 1 to 8, it is also suitable for use as a desk for children at school, an office, a table top for a dining table, and the like.

According to the laminated plastically processed lumber according to the tenth aspect of the invention, the design material has a compression rate within a range of 50% to 60% with respect to the air-dried specific gravity of the original lumber by the heat compression, and the The inner layer material has a compressibility of 20% to 40% with respect to the air-dried specific gravity of the original wood by the heat compression. Therefore, in addition to the effects described in any one of claims 1 to 10, both lightness and high surface hardness can be achieved.

According to the laminated plastically processed lumber according to the eleventh aspect of the invention, at least one of the facing surfaces of the design material and the inner layer material has a convex portion formed by a knot portion and a concave shape deformed by pressing by the knot portion. In addition to the effects described in any one of claims 1 to 10, the use of a knotted material reduces the cost due to the use of joint surfaces with parts.

FIG. 1(a) is an explanatory view using three lumbers as an example of the laminated plastic processed lumber according to the embodiment of the present invention, and FIG. 1(b) shows the three lumbers of FIG. FIG. 1(c) is an explanatory diagram of a laminated laminated lumber, and FIG. 1(c) is an explanatory diagram of a laminated plastic-processed lumber according to an embodiment of the present invention, in which the laminated lumber of FIG. 1(b) is consolidated and joined together It is an explanatory diagram of FIG. 2(a) is an explanatory view using four lumbers as an example of laminated plastic processed lumber according to the embodiment of the present invention, and FIG. 2(b) shows the four lumbers of FIG. FIG. 2(c) is an explanatory diagram of a laminated lumber laminated on a specific surface, and FIG. 2(c) is an explanatory diagram of a laminated plastic-processed lumber according to an embodiment of the present invention, in which the laminated lumber of FIG. 2(b) is subjected to consolidation processing. and are integrally joined together. FIG. 3(a) is an explanatory view using four lumbers as an example of the laminated plastic processed lumber according to the embodiment of the present invention, and FIG. 3(b) shows the four lumbers of FIG. Fig. 3(c) is an explanatory view of laminated plastic-worked lumber according to an embodiment of the present invention; Fig. 3(b) 1 is an explanatory view of consolidating and integrally joining the laminated materials of FIG. FIG. 4(a) is an explanatory view using five lumbers as an example of laminated plastic processed lumber according to the embodiment of the present invention, and FIG. 4(b) shows four lumbers of FIG. FIG. 4(c) is an explanatory diagram of a laminated lumber laminated on a specific surface, and FIG. 4(c) is an explanatory diagram of a laminated plastic-worked lumber according to an embodiment of the present invention, in which the laminated lumber of FIG. 4(b) is subjected to consolidation processing; and are integrally joined together. FIG. 5 is a cross-sectional view of a schematic configuration showing an example of a plastic-worked lumber manufacturing apparatus for forming a laminated plastic-worked lumber according to an embodiment of the present invention. FIG. 6 is an explanatory diagram for explaining an example of the manufacturing process of the laminated plastically worked lumber according to the embodiment of the present invention, (a) is an explanatory diagram of the feeding of the laminated lumber to be plastically worked, and (b) is a heat compression. Explanatory drawing of the starting state, (c) is an explanatory drawing of the heating and compression state in the sealed state, (d) is an explanatory drawing of the vapor pressure control process in the sealed state, and (e) is an explanatory drawing of the cooling state in the sealed state. , (f) are explanatory diagrams of taking out the laminated plastic-worked lumber. FIG. 7 is an enlarged explanatory view of the butt end surface of the laminated plastic-worked lumber according to the embodiment of the present invention shown in FIG. 1(c).

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7. FIG.
In addition, in the present embodiment, the same symbols and the same reference numerals mean the same or corresponding parts and functions, so duplicate descriptions will be omitted here.

First, it will be described that the lumber NW before processing, which is the raw material for the laminated plastically worked lumber LPW according to the embodiment of the present invention, is milled in advance to a predetermined size.
The thickness, width, and length of the wood NW before processing differ depending on the application, purpose, etc. of the laminated plastically processed wood LPW obtained by laminating and consolidating the wood NW. Cubical or cuboid timbers, lumber made as planks are used. Preferably, timbers NW that have been sawn as cross-grain timbers or chamfered timbers are used. It should be noted that cross-grain lumber is lumber that has been sawed in the tangential direction of the annual rings of the raw wood, that is, cross-grained lumber. It is an intermediate kidori timber that is sawed in the tangential direction of the cross grain. A cross-grained lumber usually has a butt surface (two surfaces), a cross-grain surface (two surfaces of the front and back of the tree), and a straight-grain surface (two surfaces) cut along a cross section perpendicular to the fiber direction of annual rings. In the case of straightened timber, the edge surface (two surfaces) cut in a cross section perpendicular to the fiber direction of the wood, the intermediate grain surface of the wood grain and the straight grain (two surfaces of the front and back of the wood) ), and has straight-grained surfaces (two surfaces). Note that FIGS. 1 to 4 will be described with an example of a cross-grain material.

Regarding the wood NW used as the raw material for the laminated plastic processed wood LPW, it does not matter whether it is sapwood (sapwood, white) or heartwood (red), but in general, in conifers such as cedar, the amount of tar is Where there is a large amount of sapwood, the amount of sapwood exposed by heating and compression is small compared to that of the heartwood. In addition, since the sapwood has a brighter color than the heartwood, the change in dark color when compacted is suppressed more than the heartwood, and a good appearance is maintained. In addition, the wood NW, which is used as the raw material for laminated plastic processed wood LPW, cannot be used in the state of a log because it falls down or cracks due to natural disasters such as thinned wood, wind damage, water damage, snow damage, forest fire, frost damage, and insect damage. Damaged wood, offcuts, etc. may also be used. Cost reduction can be achieved, and environmental beautification can also be contributed.

The lumber NW, which has been lumbered to a predetermined thickness, is dried to a moisture content below the fiber saturation point before being subjected to a predetermined consolidation process using a plastic-worked lumber manufacturing apparatus 100 shown in FIGS. 5 and 6 described later. be. The fiber is once dried so that the moisture content is below the fiber saturation point, preferably below the air-dried state, to give strength, and the subsequent heat compression can cause a sufficient chemical change. The moisture content of wood is the ratio of the weight of moisture to the weight of wood not containing moisture (total dry weight, dry base), and can be measured using a measuring instrument such as a high-frequency moisture content meter. In general, since moisture evaporates from the surface side of the wood, the moisture content of the wood decreases as it gets closer to the surface, but the moisture content here indicates the value measured as the moisture content of the entire wood. .

The wood NW can be dried to a desired moisture content by a known drying apparatus, for example, an artificial dryer with a built-in refrigerator or the like using known high-temperature steam as a heat source under predetermined conditions. At this time, the overall moisture content of the wood NW is measured in advance, and the moisture content at this time, the tree species of the wood NW, the thickness, etc. are used as parameters, and a drying device such as an artificial dryer or the like is used so that the moisture content after drying is a predetermined value. drying conditions, that is, predetermined temperature, humidity, drying time (in the case of cedar and cypress wood, for example, the drying temperature is about 40 to 100 ° C., the dry-wet bulb temperature difference is about 1 to 30 ° C., the drying period is about 3 to 10 days), etc. Normally, during the drying period, the drying temperature is set to gradually rise and the humidity is set to gradually fall.

Although it is possible to increase the strength by lowering the moisture content, if the moisture content of the wood NW is lowered more than necessary, the strength is impaired due to shrinkage of the wood NW, and cracks or the like occur during the drying process. In particular, when there are knots K in the wood NW, the knots K and their surroundings have high moisture absorption and desorption characteristics, and the moisture easily evaporates, so cracks at the knots K and their surroundings during the drying process. , cracks and the like are likely to occur.
Therefore, for example, in the case of cedar wood, cypress wood, etc., it is preferable to dry the wood NW so that the moisture content of the entire wood falls within the range of 5% to 15%. More preferably, the water content is in the range of 8% to 10%.

Here, in the laminated plastically processed lumber LPW according to the present embodiment, a plurality of lumbers NW (NW _D1 , NW _D2 , NW _I1 , NW _I2 , NW _I3 , etc.) are laminated, and the laminated body LW is heated and compressed. The thickness of one piece of laminated plastic processed wood LPW is obtained by performing a consolidation process, and each piece (one piece) of wood NW (NW _D1 , NW _D2 , NW _I1 , NW I2 , NW I2 , NW _I2 , NW _I3 , etc.) can be made thinner. That is, for example, as a laminated plastic processed wood LPW that can be used for applications such as a desk for school children, a study desk, a work desk in an office, a desk such as a dining table at home, a shelf board, etc., three or more thin sheets Thick wood NWs are stacked and heat-compressed. For example, thin wood NWs with a thickness of 10 mm to 30 mm, preferably 12 to 25 mm, are dried.

Therefore, each wood NW used as a raw material for laminated plastic-worked wood LPW can be dried in a short drying time, and drying cracks on the surface are less likely to occur. can be approximated to That is, even if the laminated plastic-worked wood LPW is made to have a predetermined thickness, each wood NW used as the raw material can be made thin, so the load due to drying can be reduced. Therefore, even when a material having knots is used as the raw material wood NW, it is difficult to cause knot cracking and knot dropout due to drying, and the yield can be improved. In addition, since the variation in water content between the inside and the surface side of the wood NW can be reduced, it becomes difficult to cause local compressive deformation and stress in subsequent hot compression, and internal cracking of the wood due to hot compression is prevented. Even if there are knots, cracks, fissures and the like are less likely to occur there. In addition, since the drying time of the wood NW is short, the productivity is also good.

In addition, when carrying out the present invention, means for drying the wood NW to a predetermined moisture content is not limited to artificial drying, and natural drying may be used in combination. In the above description, lumber cut from raw wood or logs is sawed into a predetermined size and then dried. It may be lumbered to a predetermined size after it is dried.

Next, the wood NWs (NW _D1 , NW _D2 , NW _I1 , NW _I2 , NW _I3 , etc.) dried to a predetermined moisture content in this way are placed in the direction perpendicular to the length direction of each grain, that is, Laminated lumber LW is formed by interposing an adhesive in the thickness direction of lumber NW.
In the present embodiment, three or more wood pieces NW are laminated, and the number of laminated wood pieces NW is set according to the application, purpose, etc. of the laminated plastically worked wood piece LPW.

As shown in FIGS. 1 to 4, in the present embodiment, the wooden pieces NW (NW _D1 , NW _D2 , NW _I1 , NW _I2 , NW _I3 , etc.) are laminated with their grain lengths matched. there is
As long as the lengths of the wood grains are matched to each other and laminated, as will be described later, even if the wood NW has knots K, when the wood NW is heated and compressed, the wood structure of the opposing laminated wood NW will change. The joints are easy to press, and compressive stress is less likely to be applied to the joints K. Therefore, when there are many knots, for example, when knots exist at a high occupancy of 10% to 20% and the difference in partial specific gravity is large, when there are knots penetrating the front and back of the wood NW, or when the wood NW has a diameter of 20 mm Even when the above knots are present, the knots are prevented from being crushed during heating and compression, and buckling deformation is prevented from occurring around them.

Further, in the present embodiment, the lumbers NW _D1 and NW _D2 are arranged so that the front and back surfaces of the laminated lumber LW formed by laminating the lumbers NW become the cross-grained surface or chamfered surface on the wood surface side. That is, the laminated lumber LW has a design surface on the cross grain surface or the chamfered surface on the wood surface side of each of the lumbers NW _D1 and NW _D2 arranged on the front and back layers, and each of the lumbers NW _D1 and NW _D2 on the opposite side. The cross-grain surface or chamfered surface of the back side is the surface facing the wood NW _I (NW _I1, NW _I2, NW _I3 , etc.) of the intermediate layer to be laminated.
As a result, the front and back layers, that is, NW _D1 and NW _D2 on the design surface side, are easily deformed by the pair of press plates 10A and 10B sandwiching the laminated wood LW during heat compression, and the compressive stress generated during heat compression can be reduced. Therefore, it is possible to prevent wood cracking due to buckling deformation of annual rings, and to reduce the internal stress, so even if a material with knots is used, cracks such as cracks are unlikely to occur in the knots during heat compression. Become. In addition, since the compression rate and the anisotropy of shrinkage are balanced between the front and back surfaces, local compression deformation and stress are less likely to occur, and distortion due to compression is small. Even if expansion/contraction force is generated due to change, the dimensional shape stability is high.

When the laminated plastic processed wood LPW of the present embodiment is applied, for example, to a top board or a shelf board used for desks such as school children's desks, study desks, office work desks, home dining tables, etc. To explain with an example, when a coniferous tree such as cedar or cypress is used as the wood NW before processing, which is the raw material of the laminated plastic processed wood LPW, three pieces with a thickness within the range of 6 mm to 15 mm are used. Lamination of timbers NW _D1 , NW _D2, NW _I1 , four timbers NW _D1 , NW _D2, NW _I1, NW _I2 , or five timbers NW _D1 , NW _D2, NW _I1, NW _I2 , NW _I3 material LW. At this time, the total thickness of the laminated lumber PW in which 3 to 5 lumbers NW _D1 , NW _D2, NW _I1, NW _I2 and NW _I3 are laminated is, for example, within the range of 20 mm to 75 mm, preferably 25 mm to 60 mm. Within range. However, when carrying out the present invention, the number and thickness of the wood pieces NW, which are the raw materials of the laminated plastic-worked wood piece LPW, are not limited to these. Although an adhesive is actually applied between the lumbers NW of the laminated lumber LW, the above thickness is a value ignoring the applied thickness of the adhesive. Here, hereinafter, when NW _D1 , NW _D2, NW _I1, NW _I2 , and NW _I3 are not particularly distinguished, they are simply referred to as “timber NW”, and the inner layer timber placed between the front and back layer timbers NW _D1 and NW _D2 NW _{I1 ,} NW _I2 , and NW _I3 will simply be referred to as "timber NW _I " when not specifically distinguished.

FIG. 1 shows an example in which three pieces of wood NW are laminated. A laminated lumber LW made by laminating three lumbers NW _D1 , NW _{D2, and} NW _I1 is arranged such that the lengths of the grains of the lumbers NW _D1 , NW _{D2, and} NW _I1 match each other, and the length of the grain is It is an arrangement in which the cross grain surface or chamfered surface on the wood surface side of each of the wood pieces NW _D1 and NW _D2 located on the front and back layers is used as the design surface.

2 and 3 are examples in which four pieces of wood NW are laminated. Laminated lumber LW formed by laminating four lumbers NW _D1 , NW _D2 , NW _I1 , NW _I2 is obtained by matching the grain lengths of the lumbers NW _D1 , NW _D2, NW _I1, NW _I2 to each other, so that the wood grain It is laminated in the direction perpendicular to the length direction, and is arranged so that the cross-grain surface or chamfered surface on the wood surface side of each of the timbers NW _D1 and NW _D2 located on the front and back layers is the design surface. At this time, the two inner layer timbers NW _{I1 and} NW _I2 placed between the timber NW _D1 and the timber NW _D2 of the front and back layers are arranged such that the opposing surfaces to be superimposed on each other are the cross grain surface on the front side of the wood or the cross grain surface as shown in FIG. It is preferable to use the chamfered surfaces side by side, or, as shown in FIG. As a result, the anisotropy of shrinkage is balanced, so distortion due to compression is small, and dimensional and shape stability is high even if expansion and contraction forces are generated due to changes in ambient environmental conditions after compaction.

That is, the laminated lumber LW formed by laminating the _{four lumbers} NW _D1 , NW _{D2 ,} NW _I1 and NW _I2 shown in FIG. The inner layer timbers NW _{I1 and} NW _I2 face the cross-grained or chamfered sides of the back side of the wood NW _{I1 and NW I2, and the inner-layer lumbers NW I1 and} NW _I2 face each other on the cross-grained or chamfered sides of the wood front side. It is. In this way, in the case where the cross-grained surface or the straightened surface side of the back side of the wood NW _D1 and NW _D2 of the front and back layers faces the cross-grained surface or the straightened surface side of the back side of the wood NW _{I1 and} NW _I2 of the inner layer, Since the lumbers NW _D1 and NW _D2 of the front and back layers are easily deformed by the pair of press plates 10A and 10B sandwiching the laminated lumber LW during heat compression, that is, the compressive force is easily concentrated, the surface hardness can be further increased. It is possible. Furthermore, since the internal stress due to the heat compression force can be reduced, even if there are many knots, even if there are knots that penetrate the front and back of the wood, or if there are knots with a diameter of 20 mm or more, the knots can be reduced during heat compression. Fractures such as cracks and fissures are less likely to occur in the portion K. In addition, when the number of the inner layer timbers NW to be arranged between the timbers NW _D1 and the timbers NW _D2 of the front and back layers is an even number of 2 or more, the front side and the back side of the wood are alternately reversed and stacked. Distortion can also be prevented by balancing the anisotropy of compression.

On the other hand, the laminated lumber LW formed by laminating the _{four lumbers} NW _D1 , NW _D2, NW _I1 and NW _I2 shown in FIG. The face side of the inner layer wood NW _I1, NW _I2 faces the cross-grained or chamfered side of the wood front side, and the inner-layered wood NW _I1, NW _I2 faces each other on the back side of the wood, the cross-grained or chamfered side It is what I did. In this way, in the case where the cross-grained surface or chamfered surface on the back side of the wood NW _D1 and NW _D2 of the front and back layers faces the cross-grained surface or chamfered surface on the wood surface side of the wood NW _{I1 and} NW _I2 of the inner layer, The front and back of the laminated wood LW are in a symmetrical relationship, and the wood NW interacts with each other to prevent warping deformation, distortion, etc. in a specific direction. Therefore, the dimensional shape stability becomes higher.

In any case, when an even number of inner-layer timbers NW _I are laminated between the timber NW _D1 and the timber NW _D2 of the front and back layers, the cross-grained surfaces on the front side of the wood or the cross-grained surfaces on the back side of the wood and the cross-grained on the back side of the wood are used. The anisotropy of shrinkage is balanced by laminating and adhering the surfaces or the chamfered surfaces so that they face each other, and it is possible to prevent warping deformation, distortion, etc. in a specific direction, so that the dimensional shape stability can be improved.

Moreover, FIG. 4 is an example in which five pieces of wood NW are laminated. Even in a laminated lumber LW formed by laminating five lumbers NW _D1 , NW _D2, NW _I1, NW _I2 and NW _I3 , each of the lumbers NW _D1 , NW _D2, NW _I1, NW _I2 and NW _I3 have grain lengths different from each other. are aligned and laminated in the direction perpendicular to the length direction of the wood grain, and the cross grain surface or the chamfered surface on the wood surface side of each of the wood NW _D1 and NW _D2 located in the front and back layers is the design surface. It is an arrangement that At this time, two pieces of wood NW _I among the three pieces of wood NW _{I1 ,} NW _I2 , and NW _I3 in the inner layer laminated between the pieces of wood NW _D1 and NW _D2 in the front and back layers are arranged so that the facing surfaces to be overlapped with each other are placed on the front side of the wood. It is preferable to use cross-grain surfaces or chamfered surfaces, or cross-grain surfaces or chamfered surfaces on the back side of the tree. As a result, the anisotropy of shrinkage is balanced, so distortion due to compression is small, and dimensional and shape stability is high even if expansion and contraction forces are generated due to changes in ambient environmental conditions after compaction.

That is, even if the number of the inner layer timbers NW _I laminated between the timber NW _D1 and the timber NW _D2 of the front and back layers is three or more, even if the number of timbers NW I is an odd number, the front side and the back side of the wood may face each other in part. However, it is possible to prevent distortion due to compression by laminating and bonding the cross-grained surfaces or straightened surfaces on the front side of the wood or the cross-grained surfaces or straightened surfaces on the back side of the wood facing each other. Become. In addition, even if expansion and contraction forces occur due to changes in the surrounding environmental conditions after consolidation, the timbers that are stacked on top of each other interact with each other to prevent warping and deformation in a specific direction. can be secured.

Here, when using a material with knots for the wood NW as the raw material of the laminated plastic-worked wood LPW, it is preferable to overlap a part of another wood NW with no knots on a part of the wood NW with the knot K. That is, the portion (1 cm ³ unit) of the mating material that is opposed to the location where the knot K of the wood NW is located has a lower specific gravity and a lower fiber density than the location where the knot K is located. In a portion without knots in the wood structure, that is, in a portion with low specific gravity and low density of fibers without knots K, when heated and compressed, it is pressed by the knots K of the wood NW and can be softened and deformed. Depending on the compressibility, a cushioning effect suitable for the compression is obtained, and even if the wood is heated and compressed, the knots follow the environment, so that the knots K of the wood NW are less likely to be subjected to compressive stress. In other words, even if a material with knots is used, by stacking the wood NWs together, the specific gravity is different in the direction perpendicular to the length direction of the wood grain, that is, in the thickness direction of the wood NW. Buckling deformation of the fibers around the knots of the wood NW is suppressed, and excessive stress is less likely to be applied to the knots and their surroundings. Furthermore, in the present embodiment, even if the wood NW _D1 and the wood NW _D2 of the front and back layers are highly compressed, the wood NW _I of the inner layer is low-compressed. An unreasonable compressive load is hard to be applied to the portion K, and the hard knot portion K is hard to be distorted and stressed. In addition, since the compression is balanced between the front and back sides, it is difficult to cause local compressive deformation and stress. Therefore, it is possible to obtain a laminated plastic processed wood LPW having a mechanical strength higher than that of the original wood by consolidation without causing crushing, breakage, fissures, cracks, etc. of the knots K.

Then, in the present embodiment, an adhesive is applied to the facing surfaces of the wood pieces NW to be laminated before heat compression.
As the adhesive for bonding the pieces of wood together, any adhesive can be used as long as it can integrally bond pieces of wood together under the conditions of the subsequent pair of press plates 10A and 10B, that is, the heat compression process using a hot press. good. For example, adhesives for bonding wood together include water-based vinyl urethane-based adhesives (water-based polymer isocyanate-based adhesives), urethane resin-based adhesives, vinyl acetate resin-based adhesives, urea resin-based adhesives, and epoxy resins. A resin-based adhesive, a phenolic resin-based adhesive, a synthetic rubber-based adhesive, or the like can be used. In particular, in the present embodiment, a thermosetting adhesive that adheres wood pieces together by being cured during heat compression, which will be described later, or a two-liquid mixing reaction curing type adhesive is used. The amount of adhesive to be applied at this time is determined by the type of adhesive, etc. For example, in the case of a water-based vinyl urethane adhesive, the amount to be applied is preferably 200 g/m ² or more. If the water-based vinyl urethane adhesive is used, the adhesive can easily permeate even wood made of coniferous trees, and a sufficient adhesive strength can be obtained to firmly bond the wood together in the subsequent heating and compression process. In particular, in the case of a material with knots, it also permeates the knots K, making it possible to relax the compressive stress applied to the knots K in the subsequent heating and compression process, and to protect the knots. It is effective in preventing cracking of the joint K during the compression process.
Note that the method of applying the adhesive is not particularly limited, and the adhesive may be applied to one side of the wood NW. If applied, it is possible to apply the adhesive for bonding with less labor and man-hours.

At this time, the laminated lumber LW, which is obtained by laminating three or more lumbers NW with an adhesive interposed therebetween, is a lumber obtained by adding moisture to the lumbers NW _D1 and NW _D2 of the front and back layers after drying. may be used. That is, when carrying out the present invention, after drying to a predetermined moisture content as described above, when wood is laminated, NW _D1 and NW _D2 on the upper and lower layers are heat-compressed. In order to facilitate the stacking, moisture may be added to the woods NW _D1 and NW _D2 arranged on the upper layer side and the lower layer side when laminated, that is, humidification may be performed. For example, by immersing the whole of the dried lumbers NW _D1 and NW _D2 in water for a predetermined time (for example, the immersion time is about 5 minutes), water can be added to obtain a predetermined moisture content. The means for adding moisture to the surface side of the dried wood NW _D1 and NW _D2 is not limited to immersing the wood NW _D1 and NW _D2 in water, and spraying or spraying water on a specific surface with a spray or the like is also possible. Alternatively, water may be applied with a brush or the like.

Next, the laminated lumber LW, which is obtained by laminating three or more lumbers NW with an adhesive interposed therebetween, is heat-compressed to perform consolidation by heat-compression and compression fixation, and curing of the adhesive. The wood is joined together by

Here, as shown in FIGS. 5 and 6, the plastic-worked lumber manufacturing apparatus 100 for consolidating the laminated lumber LW in which a plurality of lumbers NW are laminated mainly includes an upper press platen 10A and a lower press platen 10B. A press platen 10 forming an internal space IS by a structure divided into two, and a peripheral edge portion 10a of the upper press platen 10A facing the peripheral edge portion 10b of the lower press platen 10B. and a pipe port 12a that communicates with the interior space IS from the upper surface side of the upper press platen 10A and supplies steam into the interior space IS. a valve V4 on the upstream side thereof; a pipe 13 communicating with the inner space IS from the side surface of the lower press platen 10B and having a pipe port 13a for discharging water vapor from the inner space IS; 13, a valve V5 on the downstream side thereof, a drain pipe 14 connected to the valve V5, and the like.

In the upper press platen 10A and the lower press platen 10B of the press platen 10, piping lines 15 and 16 are formed for raising the temperature to a desired temperature by passing high-temperature steam through them. , 16 are connected to pipes ST2 and ST3 branched from the pipe ST1 on the steam supply side, and pipes ET1 and ET2 on the steam discharge side, respectively. Valves V1, V2 and V3 and a pressure gauge P1 for detecting the steam pressure in the pipe ST1 are arranged in the middle of the pipes ST1, ST2 and ST3 on the steam supply side, and pipes ET1 and ET2 on the steam discharge side. is connected to a drain pipe 14 via a valve V6.

Furthermore, the press platen 10 has a cooling water supply side for cooling to a desired temperature by passing low-temperature cooling water instead of water vapor through pipes 15 and 16 formed in the upper press platen 10A and the lower press platen 10B. Pipes ST12 and ST13 branched from the pipe ST11 are connected to the pipes ST2 and ST3, respectively. Further, valves V11, V12 and V13 are arranged in the middle of the pipes ST11, ST12 and ST13 on the cooling water supply side.

A boiler device that supplies water vapor to the pipe ST1, a cooling water supply device that supplies cooling water to the pipe ST11, and an upper press platen 10A are raised/lowered with respect to the lower press platen 10B on the fixed side of the press platen 10 to apply pressure. A press lifting device including a hydraulic mechanism for pressing is omitted.
In the present embodiment, high-temperature steam is introduced to heat the upper press platen 10A and the lower press platen 10B of the press platen 10. However, when the present invention is carried out, the heating medium for the press platen 10 is high-temperature steam. There is no limitation, and oil or the like may be used, or wood may be heated by a heating means such as high-frequency heating, microwave heating, or a heater. In particular, for high-frequency heating of lumber, a method of heating lumber from the center with a high frequency slightly lower than microwaves is more suitable than dielectric heating by microwaves.

In the press platen 10 made of iron or the like, a flat mold having a flat size capable of pressing the entire front and back surfaces in the direction perpendicular to the stacking direction of the laminated wood LW is used. In order to prevent the blackening due to iron ion contamination, for example, steel materials such as stainless steel and aluminum are used for the mold, and the front and back contact surfaces of the laminated wood LW are plated. Further, the material of the seal member 11 for sealing the internal space IS is not particularly limited, but silicone rubber, silicone resin, etc., which are excellent in heat resistance and water resistance, are usually used.

In order to consolidate the laminated lumber LW using the plastically worked lumber manufacturing apparatus 100 configured as described above, first, as shown in FIG. On the other hand, the upper press platen 10B on the movable side is raised, and the laminated lumber LW is placed on the lower press platen 10B on the fixed side.

Here, in the present embodiment, the direction of press compression by the press platen 10 divided into the upper press platen 10A and the lower press platen 10B is the direction perpendicular to the grain length direction of the laminated wood LW. A compressive force is applied in a direction perpendicular to the surfaces (front and back surfaces perpendicular to the thickness direction of the laminated wood LW).

At this time, in the present embodiment, since the front and back surfaces of the laminated wood LW are the cross grain surface or the chamfered surface on the front side of the wood, one of the front and back layers (outer layers) of the laminated wood LW (lower layer in the figure) The wood face side of the cross grain surface or chamfered face of NW _D2 is opposed to the lower press platen 10B, and the other (upper layer in the figure) wood NW _D1 is placed on the wood face side of the cross grain surface or chamfered face of the upper press platen 10A. , and the cross grain surface or chamfered surface on the surface side of the wood surface perpendicular to the length direction of the wood grain of the laminated lumber LW is the surface to be press-compressed by the press platen 10 .

In carrying out the heating and compression treatment, the surface side of the laminated wood LW perpendicular to the grain direction is opposed to the upper press platen 10A and the lower press platen 10B of the press platen 10, and the lower press platen on the fixed side is pressed. As shown in FIG. 6(b), first, the upper press platen 10A is lowered under a predetermined pressure (for example, 0.05 to 0.3 [MPa]) to laminate the laminated lumber LW placed on 10B. The upper surface of the timber LW, that is, the cross-grained surface or chamfered surface of the timber NW _D1 perpendicular to the grain length direction is brought into contact for a predetermined time (for example, 10 to 120 seconds). At this time, water vapor at a predetermined temperature (for example, 110 to 210 [° C.] and a temperature rising treatment time of 10 to 25 [minutes]) is passed through the upper press platen 10A and the lower press platen 10B. 10A and lower press platen 10B are heated to a predetermined temperature (for example, 110 to 210[° C.]).

Then, the compression pressure of the upper press platen 10A is set to a predetermined pressure (for example, 2 to 5 [MPa], 20 to 50 kg/cm ² ) relative to the lower press platen 10B on the fixed side, and the upper press platen 10A is lowered. The laminated lumber LW is heated and compressed by the upper press platen 10A and the lower press platen 10B, for example, at a processing time of 0.5 to 3 [minutes] and a compression speed of 15 to 100 [mm/minute]. When the upper press platen 10A descends, the laminated lumber LW is heated and compressed by the upper press platen 10A and the lower press platen 10B, and the peripheral edge portion 10a of the upper press platen 10A contacts the peripheral edge portion 10b of the lower press platen 10B. As shown in FIG. 6(c), the internal space IS formed by the upper press platen 10A and the lower press platen 10B is sealed by the seal member 11 disposed on the peripheral edge portion 10a of the upper press platen 10A. .

In the present embodiment, the vertical dimension of the internal space IS formed by the upper press platen 10A and the lower press platen 10B of the press platen 10 when the internal space IS is in a sealed state via the seal member 11. The interval is set to the finished dimension in the thickness direction when the press platen 10 forms the plastically processed lumber PW having a predetermined compressibility with respect to the thickness of the laminated lumber LW. Therefore, the compressibility of the entire thickness of the laminated wood LW, that is, the change in the plate thickness (compression amount) due to the compression of the laminated wood LW, is such that the peripheral edge 10a of the upper press platen 10A hits the peripheral edge 10b of the lower press platen 10B. It will be determined by contact. The pressure, heating temperature, heating time, compression speed, etc., of the press platen 10 at this time are set to optimum values in advance through experiments or the like using factors such as the tree species of the wood and the moisture content of the dried wood as parameters.

With respect to the press platen 10 heated to a predetermined temperature in this way, when the lower press platen 10B is fixed and the upper press platen 10A is moved to contact the upper surface of the laminated wood LW with a predetermined pressure and is lowered at a predetermined compression speed, the laminated wood is lowered. Changes in the chemical properties of wood components from the front and back layers of LW cause a decrease in strength (hydrolysis of amorphous components such as hemicellulose and lignin, and a decrease in softening point), and the cells are compressed and deformed, reducing the voids in the cells. To go.

In particular, in the present embodiment, a laminated wood LW formed by laminating three or more _{woods NW} is sandwiched between a pair of press plates 10 and thermally compressed. However, since the sawn wood NWs are arbitrarily combined and laminated, the wood structure of the front and back layers of the wood NW _D1 , NW _D2 and the inner layer of the wood NW _I is not continuous, Since the wood structure changes between the wood NW _D1 , NW _D2 of the front and back layers and the wood NW _I of the inner layer, heat compression from the front side to the back side of the wood NW _D1 , NW _D2 of the front and back layers is performed. The angle of the annual ring line RL is usually sharp from the front side to the back side of the wood NW _D1 and NW _D2 of the front and back layers, and the specific gravity, hardness, and fiber strength are also high, so that compression deformation is difficult. is. In particular, when the tree ring angle of the wood NW _I of the inner layer is smaller than that of the wood NW _D1 , NW _D2 of the front and back layers, it is possible to increase the difference in compression rate between the design materials PW _D1 , PW _D2 described later and the inner layer material PW _I1 . It is possible to increase the surface hardness by increasing the compressibility of the design materials PW ₁ and PW ₂ without cracking even if there are knots.
Therefore, due to the difference in mechanical properties when heated and compressed, the timbers NW _D1 and NW _D2 arranged in the front and back layers of the laminated lumber LW are highly compressed, and the inner layers arranged between the timbers NW _D1 and NW _D2 in the front and back layers. The wood NW _I can have a lower compression than the woods NW _D1 and NW _D2 of the front and back layers.

As described above, in the present embodiment, a plurality of lumbers NW are laminated to form a laminated lumber LW, which is sandwiched between a pair of press plates 10A and 10B and thermally compressed. Even if the portion K exists, the wood component of the low specific gravity portion without knots of the wood NW on the opposite side that is superimposed on it softens during heat compression, and is deformed by the pressure of the hard knot K, so that the hard knot. Do not apply compressive stress to K. Furthermore, even if the timbers NW _D1 and NW _D2 of the front and back layers of the laminated timber LW are highly compressed, the inner layer timber NW _I arranged between the timbers NW _D1 and NW _D2 of the front and back layers is compressed more than the timbers NW _D1 and NW _D2 of the front and back layers. Since the compression is also low, even if the joint K exists, an excessive compressive force is not applied to the joint K. Therefore, even if the laminated wood NW has a knot portion K, the knot portion K is less likely to be broken or crushed, or the fibers around the knot portion to undergo buckling deformation during heating and compression, and the knot portion K is less likely to crack or split.

If the peripheral edge portion 10a of the upper press platen 10A and the peripheral edge portion 10b of the lower press platen 10B are configured with, for example, a jig, a formwork, a gauge, etc. for controlling the thickness, the plastically processed wood PW can be obtained as desired. The height of the peripheral edge portion 10a of the upper press platen 10A and the peripheral edge portion 10b of the lower press platen 10B can be adjusted according to the finished thickness. Furthermore, at this time, it is also possible to arrange a restrictor (spacer) (not shown) for restricting lateral (horizontal) extension, for example, on the side surface of the laminated lumber LW. If the change in extension of the laminated lumber LW in the lateral direction (horizontal direction), that is, the change in extension in the direction perpendicular to the direction of compression is restricted by the restrictor, it becomes easier to fix the specific dimensions and specific gravity, thereby making it easier to fix the product. Variation can be prevented and high quality can be ensured. When such restrictions are applied, the density may increase at the ends of the wood in the width direction. Conversely, if there is no regulation, the width-direction end portions of the lumber may have a lower density than the central portion. Depending on the density difference in the width direction of the wood, it is also possible to cut the surface of the wood on the side of the width direction end after the consolidation process. Furthermore, when commercializing, a plurality of laminated lumber LWs are arranged in the grain length direction of the laminated lumber LW and in the width direction orthogonal to the grain length direction, and are integrally consolidated and joined. is also possible.

Next, the compression pressure of the upper press platen 10A and the lower press platen 10B is maintained in the closed state of the internal space IS shown in FIG. , 110 to 210[° C.]), fixing of the heat compression treatment of the wood, so-called fixing treatment of the wood is performed.
For example, a predetermined steam pressure is supplied to the sealed internal space IS via a pipe 12 and a pipe port 12a (FIG. 5) connected to the valve V4 to compress the upper press platen 10A and the lower press platen 10B. While maintaining the pressure and heating temperature at the same predetermined pressure and temperature as the pressure and heating temperature at the time of heat compression, the internal space IS in a sealed state is at a predetermined temperature and vapor pressure for a predetermined time (for example, 20 minutes to 90 minutes). retained. By introducing high-temperature steam at a predetermined temperature (for example, 110 to 210 [° C.]) into the internal space IS and setting the internal space IS in a sealed state to a predetermined temperature and steam pressure, the sealed state is achieved by the action of the high-temperature and high-pressure steam. A sufficient chemical change is caused to the heat-compressed lumber arranged in the internal space IS of the lumber to make the properties uniform. As a result, it is possible to form a laminated plastically worked wood LPW that does not return when the subsequent cooling compression is released.

At this time, high-temperature and high-pressure steam pressure can freely flow between the peripheral surface of the heat-compressed lumber and the inside thereof. The inside of the sealed internal space IS may be adjusted to a predetermined vapor pressure. For example, excess moisture in the interior space IS is removed based on the moisture content of the front and back surfaces of the wood, and the interior space IS is adjusted to a predetermined vapor pressure. At this time, when the heat-compressed lumber is fixed in the sealed state of the internal space IS, the vapor pressure of the internal space IS is detected by the pressure gauge P2 as the vapor pressure control process, and the valve V5 is appropriately adjusted. , is opened and closed. As a result, high-temperature and high-pressure steam can be discharged from the internal space IS to the drain pipe 14 side through the pipe port 13 a and the pipe 13 . Also, if necessary, a predetermined steam pressure can be appropriately supplied to the internal space IS that is in a sealed state.

Then, as shown in FIG. 6(d), immediately before the shift from heating compression to cooling compression by the upper press platen 10A and the lower press platen 10B, the valve V5 is opened as steam pressure control processing, thereby High-temperature and high-pressure steam is discharged from the compression space IS to the drain pipe 14 side through the port 13 a and the pipe 13 . As a result, heat compression treatment of wood, so-called fixation of wood, is further promoted. At this time, the supply of water vapor for maintaining the upper press platen 10A and the lower press platen 10B at the specific temperatures is temporarily stopped.

Finally, as shown in FIG. 6(e), normal-temperature cooling water is passed through the piping 15 of the upper press platen 10A and the piping 16 of the lower press platen 10B, thereby cooling the upper press platen 10A and the lower press platen 10B. It is cooled to around room temperature and held for a predetermined time (for example, 20 to 90 [minutes]). At this time, the compression pressure of the upper press platen 10A against the lower press platen 10B on the fixed side is kept at the same predetermined pressure (for example, 2 to 5 [MPa]) as the pressure at the time of heat compression. 10A and lower press platen 10B are cooled.
After that, as shown in FIG. 6(f), the upper press platen 10A is raised with respect to the lower press platen 10B on the fixed side, and the laminated plastic processed wood LPW _P that has undergone the consolidation processing by heat compression and compression fixing is placed inside. A series of processing steps is completed by removing from the space IS. In the laminated plastically worked wood LPW _P taken out from the internal space IS, the adhesive applied between the woods NW is hardened by heating and cooling in a series of processing steps, and the woods are integrally laminated and joined.

Thereafter, usually, in order to ensure the flatness of the product, only one surface or both surfaces of the laminated plastic-worked lumber LPW _P are cut. Moreover, you may cut a side surface. After cutting the laminated plastically worked wood LPW _P , it becomes laminated plastically worked wood LPW as a finished product. If necessary, the surface of the laminated plastically worked wood LPW may be surface-coated with a resin or the like as a countermeasure against moisture and dirt.

In the present embodiment, the laminated plastic processed lumber LPW manufactured by such a manufacturing method is obtained by sandwiching and pressing the laminated lumber LW formed by laminating the lumber NW between a pair of press plates 10A and 10B. The timbers NW _D1 and NW _D2 located in the front and back layers of the laminated timber LW are highly compressed, and the inner layer timber NW _I located between the timbers NW _D1 and NW _D2 in the front and back layers is compressed more than the timbers NW _D1 and NW _D2 in the front and back layers. It is a plastic working with low compression.

Further, the laminated plastic-worked lumber LPW according to the present embodiment is produced by laminating a plurality of lumbers NW in a specific direction and interposing an adhesive between the lumbers NW to produce the laminated lumber LW. By heat-compressing using 100, the lumbers are integrally laminated and joined with an adhesive.

In particular, in the present embodiment, since the adhesive is applied between the wood pieces NW of the laminated wood pieces LW before heat compression, the adhesive is cured during the heat compression for consolidation of the laminated wood pieces LW, and the wood pieces NW are integrated. join to That is, by heating and compressing the laminated lumber LW, the lumbers are joined while being compacted. As a result, compared to the case where the timber NWs are separately joined together via an adhesive by pressure using a press plate or the like and then subjected to the consolidation process, or the timbers laminated and subjected to the consolidation process are separately processed after the consolidation process. Compared to the case where the parts are integrally joined by pressing with a press platen or the like via an adhesive, the number of manufacturing steps is reduced and the manufacturing time is also shortened.

That is, the laminated plastic-worked lumber LPW according to the present embodiment is composed of two thin design materials PW _{D1 and} PW obtained by highly compressing the lumber NW _D1 and NW _D2 arranged in the front and back layers of the laminated lumber LW by thermal compression. _D2 and one or more pieces of wood NW _I arranged between the woods NW _D1 and NW _D2 of the front and back layers of the laminated wood LW are compressed by heating to a lower compression than the design materials PW _{D1 and} PW _D2 of the front and back layers. It is formed from one or more thick inner layer materials PW _I (PW _I1 , PW _I2 , PW _I3 , etc.), and the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I are laminated and joined together to be integrated. It is a thing. Hereinafter, the inner layer materials PW _{I1 ,} PW _I2 , and PW _I3 arranged between the design materials PW _{D1 and} PW _D2 of the front and back layers will be simply referred to as “inner layer materials PW _I ” when not specifically distinguished.

Here, the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I can be distinguished from each other by changes in the joint line L and the annual ring line RL, which are densely formed at their boundaries. , In the design materials PW _{D1 and} PW _D2 arranged in the front and back layers of the laminated plastic processed wood LPW, the amount of compressive deformation of the cells is large due to high compression, and the annual ring line RL is narrow, dense, and thin. In the inner layer material PW _I disposed between the design materials PW _{D1 and} PW _D2 , the compression is lower than the design materials PW D1 and PW _D2 , the amount of compressive deformation of the cells is small, the annual ring line RL is wide, the density is low, and the thickness is high. . Therefore, the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I have a large difference in the amount of compressive deformation of cells due to heat compression.

Specifically, in the laminated plastic-worked wood LPW according to the present embodiment, the design materials PW _{D1 and} PW _D2 are compressed by heating to 45% to 65% with respect to the air-dried specific gravity of the original wood NW, preferably Compressed at a compression rate within the range of 50% to 60%, the inner layer material PW _I is compressed by heating to a compression rate of 10% to 40%, preferably 20% to 40%, relative to the air dry specific gravity of the original wood NW. It is compressed with a compression rate within the range of . As a result, the specific gravity of the surface can be made higher than the specific gravity of the whole, and lightness, surface hardness, and strength can be achieved at the same time.
The compressibility is obtained from the air-dried specific gravity of the original wood NW and the air-dried specific gravity measured by cutting out the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I of the laminated plastic processed wood LPW at the joint surface. is calculated, and considering the difference in specific gravity due to the presence of knots, the measurement of a specific part may not necessarily fall within the above range. In addition, even if there is an error due to measurement, etc., since it deals with natural objects, it is not impossible to implement it, and it does not deny the intervention of the error.

In the present embodiment, the difference in compression rate between the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I is, as described above, due to the combination and lamination of the timber NWs that have been sawn in a predetermined manner, and the timber structure between the timbers NW. Using the fact that resistance is generated there, the wood NW _D1 and NW _D2 of the front and back layers are greatly compressively deformed, while the wood NW _I inside between the wood NW _D1 and NW _D2 of the front and back layers is compressively deformed. It is a reduced amount. Then, in the case of consolidating the combination and lamination of the lumbers NW that have been sawn in a predetermined manner, depending on the combination of the lumbers NW _D1 and NW _D2 of the front and back layers and the lumber NW _I inside, for example, the lumber to be laminated It is possible to easily control the characteristics such as the surface hardness of the consolidated plastically worked wood LPW by combining the size of the annual ring angle of the NW, the combination of the material with knots and the material without knots, and the like.

In the laminated plastically worked wood LPW according to the present embodiment, which is composed of the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I , the design materials PW D1 and PW _D2 and the inner layer material PW _I have different compression amounts and consolidation densities. As a whole, the mechanical strength is higher than that of the original wood NW and the laminated wood LW due to the consolidation process and bonding between the woods with an adhesive. In particular, the design materials PW _{D1 and} PW _D2 are compressed to a higher degree than the inner layer material PW _I by the consolidation process, so that the voids in the cell lumen are reduced and the wood is hard and strong.

In this way, two thin design materials PW _{D1 and} PW _D2 obtained by highly compressing the timbers NW _D1 and NW _D2 arranged on the front and back layers of the laminated timber LW by thermal compression, and the timber NW _D1 of the laminated timber LW. , and NW _D2 , and an inner layer material PW _I that is made by heating and compressing the internal wood NW _I arranged between the design materials PW _{D1 and} PW _D2 and having a thickness lower than that of the design materials PW D1 and PW D2. In the laminated plastic processed wood LPW of the form, by highly compressing only the design materials PW _{D1 and} PW _D2 of the front and back layers, high surface hardness is achieved even though the overall weight is secured by low compression rate and low specific gravity. Obtainable.
Therefore, for example, in laminated plastic processed wood LPW consisting of design materials PW _{D1 and} PW _D2 with a predetermined compression ratio and density distribution and inner layer material PW _I by consolidation using wood with a low specific gravity such as cedar and cypress It is possible to make the material lighter than hard and high-specific-gravity broad-leaved trees such as Mizunara oak and Japanese zelkova, even if the surface hardness is the same or higher. That is, it is possible to achieve both lightness and surface hardness.

In the example of consolidating conifers such as cedar or cypress, the air-dried specific gravity of laminated plastically worked wood LPW is in the range of 1.2 times or more and 1.7 times or less than the air-dried specific gravity of wood NW before processing. It is preferably within the range of 1.3 times or more and 1.6 times or less. As a result, the design materials PW _{D1 and} PW _D2 that are highly compressed can provide high surface hardness and strength to eliminate the susceptibility of the original wood to scratches, while ensuring lightness.
In particular, the design materials PW _{D1 and} PW _D2 are highly compressed at a compression ratio of 45% to 65%, preferably 50% to 60%, relative to the air-dry specific gravity of the original wood NW by heat compression. As a result, the properties of the wood changed and the surface hardness increased significantly.

If surface hardness, strength, and lightness can be achieved at the same time, for example, it will be suitable for use as a top board for school desks, etc., which require easy carrying, writing, and resistance to scratches by cutters, etc. Furthermore, if it is lightweight for use as a top board or shelf board of a desk, etc., it is possible to increase the degree of freedom in designing support members such as legs that support it even when used as a top board or shelf board. becomes.

In addition, in the laminated plastic processed lumber LPW according to the present embodiment, which is composed of these highly compressed, thin design materials PW _{D1 and} PW _D2 and the low-compressed, thick inner layer material PW _I between them, the overall thickness of the laminated lumber LW is reduced. Since it is possible to suppress the increase in weight due to the reduction in volume and the increase in the overall specific gravity, high surface hardness can be secured by the highly compressed design materials PW _{D1 and} PW _D2 . can be provided at low cost.

Furthermore, in the laminated plastically worked wood _LPW of the present embodiment, the design materials PW _{D1 and PW D2} of the front and back layers are dense and hard, but the design materials _{PW D1,} PW Since it has a lower density than _D2 , it has a cushioning function due to the softness of the original wood NW, even when objects such as small objects collide with it, or when it collides with objects such as walls and floors. However, the impact can be absorbed and mitigated. Therefore, even if an impact is applied to the laminated plastic processed wood LPW, the impact noise is small, the design materials PW _{D1 and} PW _D2 are less likely to be damaged, and the colliding object is prevented from being damaged or damaged. Furthermore, for example, when it is used for the top plate of a study desk, etc., it can be expected to have an effect of absorbing writing sounds and the like, and an effect of soundproofing. In addition, even if the design materials PW _{D1 and} PW _D2 of the front and back layers are highly compressed and highly dense, the inner layer material PW _I inside them is low compression and low density. In addition, the design materials PW _{D1 and} PW _D2 , which are denser than the inner layer material PW _I , can increase the holding force of the joining members. Furthermore, since the internal inner layer material PW _I has a low density, it is easy to cut the butt end surface and the end surface side, and cutting and assembly are easy.

Then, the laminated plastically worked wood LPW of the present embodiment is obtained by stacking wood NWs, compressing them, and laminating and bonding them together. With respect to LW, the thickness of the wood NW _D1 and NW _D2 arranged on the front and back layers is highly compressed, and the internal wood NW _I arranged between the front and back NW _D1 and NW _D2 is made more than the wood NW _D1 and NW _D2 of the front and back layers. The compression rate is set to be low, and instead of uniformly compressing the entire thickness of each wood NW, the compression rate is different between the wood NW _D1 and NW _D2 arranged in the front and back layers and the wood NW _I in the inner layer between them. . Preferably, the compressibility of the decorative materials PW _{D1 and} PW _D2 is in the range of 1.5 to 5 times, more preferably in the range of 2 to 4 times the compressibility of the inner layer material PW _I . In terms of air-dry specific gravity, the air-dried specific gravity of the design materials PW _{D1 and} PW _D2 is preferably 1.3 times or more and 1.8 times or less, more preferably 1.8 times the air-dried specific gravity of the inner layer material PW _I. .4 times or more and 1.6 times or less.

Therefore, according to the laminated plastically worked wood LPW of the present embodiment, the design materials PW _{D1 and} PW _D2 formed by highly compressing the thickness of the wood NW _D1 and NW _D2 arranged in the front and back layers of the laminated wood LW provide high surface hardness. , while ensuring strength, the inner layer material PW _I in which the thickness of the intermediate layer wood NW _I arranged between the wood NW _D1 and NW _D2 of the front and back layers of the laminated wood LW is made lower in compression than the design materials PW _{D1 and} PW _D2 . As a result, a strong compressive force is not applied to the entire thickness of the laminated lumber LW during heat compression.
In addition, the internal inner layer material PW _I is made low compression by planar press compression from the top and bottom direction, while the design materials PW _{D1 and} PW _D2 sandwiching the inner layer material PW _I are made highly compressed, so that the front and back are well balanced. , stress concentration and stress in a specific direction are difficult to enter during heating and compression.

In addition, since the wood structure can be softened and deformed by heat compression in the consolidation process, when wood NWs are stacked and heat-compressed, even if there are knots K, the hard knots K become the opposing member, that is, another member. A soft portion of the piled wood NW which has no knots and is easily softened and deformed and has a low specific gravity is pressed and bites into the portion. Therefore, the movement of the joint K is not constrained or regulated when it is heated and compressed. That is, even if the wood NW has knots K, the wood structure of the corresponding mating material stacked thereon is softened and deformed, so that when a compressive force is applied in a direction perpendicular to the length direction of the wood grain. Moreover, the movement of the joint K is not restrained or regulated. Therefore, the joint K is less likely to be stressed by the thermal compressive force, and a strong compressive load is not applied to the joint K.

In other words, the knot K has a high specific gravity and is hard, and is resistant to compression due to the difference in the fiber direction between the annual ring line RL and the knot K. Since the NWs are stacked and compacted, when a compressive force is applied in a direction perpendicular to the length of the wood grain, the knots K, which are resistant to compression, are transferred to another piece of wood that has knots K. By pressing the softened part of the wood due to heat compression, the mating material softens and deforms due to the pressing, so that the compressive force in the direction perpendicular to the length direction of the wood grain is buffered, so the knot K is forced to compress. Power and stress are hard to apply.

Thus, in the laminated plastically worked wood LPW of the present embodiment, even if there is a knot K, the design materials PW _{D1 and} PW _D2 of the front and back layers are highly compressed, and the internal inner layer material PW _I is lowly compressed. In addition to not applying strong compressive force and compressive stress to the inside of the laminated wood, the wood structure of the mating material stacked at the joint K is softened and deformed, so that the joint K is subjected to a strong compressive load, Compressive stress is not applied and little compressive stress is generated in the knot K. Therefore, even if a material with knots is used, for example, even if the knots K run perpendicularly or obliquely to the length direction of the grain of the wood NW, the knots K are crushed during heat compression, Fractures such as cracks and fissures are less likely to occur.

In particular, the design materials PW _{D1 and} PW _D2 of the front and back layers are highly compressed in this way, and the inner layer material PW _I of the inner layer is made low compression, so that it is difficult to apply compressive stress to the inside. However, in the consolidation process, even if a wood NW has a knot K, it is difficult for a strong compressive load to be applied to the knot K due to the softening deformation of the wood structure of the corresponding mating material that is superimposed on the wood NW. Even if the compressibility of certain design materials PW _{D1 and} PW _D2 is increased, the knots K are less likely to crack. Therefore, it is possible to increase the surface hardness and strength without causing cracks, fissures, and the like at the knots K.

In addition, the structure of the knot K tends to decrease in size from the front side of the wood to the back side of the wood, but in the design materials PW _{D1 and} PW _D2 , the cross grain surface or the chamfered surface on the front side of the wood is the pressed surface. Therefore, even if there are knots in the highly compressed decorative materials PW _{D1 and} PW _D2 , the compressive force in the direction perpendicular to the length direction of the grain allows the low-compression inner layer material PW _I to be superimposed on them. It is easy to press and deform the softened part. Therefore, even if there are knots in the highly compressed design materials PW _{D1 and} PW _D2 , the low-compression inner layer material PW _I overlaid on them makes it difficult for the movement of the knots due to the thermal compression force to be restrained. High surface hardness and strength due to the high compression of the materials PW _{D1 and} PW _D2 can be combined with a design surface in which cracks such as cracks and fissures at the knots K are unlikely to occur.

In addition, in the laminated plastic-worked wood LPW according to the present embodiment, the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I are laminated with the grain length direction aligned with each other. Even when a certain material is used, the compression stress applied to the knot portion K can be reduced because the knots can easily press against the wood structure of the opposing mating material that is laminated during heating and compression. Therefore, when there are many knots, for example, when knots exist at a high occupancy of 10% to 20% and the difference in partial specific gravity is large, when there are knots penetrating the front and back of the wood, or when the diameter is 20 mm or more Even if there are knots, cracks and fissures are less likely to occur at the knots and their surroundings.

As shown in FIGS. 1 to 4, in the laminated plastically worked wood LPW obtained by consolidating a material having knots in this way, the hard portions of the knots K of the wood NW are opposed to each other, i.e. , By pressing a soft portion of another piled wood NW that is free from knots and easily softened and deformed, a knot K is formed at one or more locations on the facing surfaces of the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I. It has a joint surface BF formed by a convex portion P and a concave portion D deformed by a knot portion K.

Then, by consolidating the wood NW using a material with knots, convex portions due to the knots K are formed on one or more of the facing surfaces of the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I. In the laminated plastic processed wood LPW having a joint surface BF formed by P and a concave portion D deformed at the knot K, the knots are hard, so the internal resistance is high, so the heating compression force is concentrated on the design materials PW _{D1 and} PW _D2 . This makes it possible to increase the density and specific gravity of the design materials PW _{D1 and} PW _D2 and increase the surface hardness and strength.
That is, at least one of the facing surfaces of the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I has a joint surface BF formed by a convex portion P formed by the knot K and a concave portion D deformed by the knot K. Laminated plastic processed lumber LPW provides higher surface hardness and strength. As a result, the surface is resistant to shallow and fine scratches caused by writing, cutters, etc., and is suitable for use as a top plate for school children's desks, home learning desks, office desks, dining table desks, etc., which are prone to such scratches. is.
In addition, the joint strength can be increased by biting into the laminated mating member of the knot portion K, and the mechanical strength of the entire laminated plastic-worked wood LPW can also be improved.

In addition, in the laminated plastically worked wood LPW of the present embodiment, the design materials PW _{D1 and} PW _D2 on the front and back sides are densely compacted, so that moisture can be absorbed and released when the ambient environmental conditions change. is suppressed, the dimensional and shape stability is high even if the ambient environmental conditions change. That is, even if the thickness is reduced from the original lumber by consolidation, distortion hardly occurs, and even if the thickness is thin, distortion hardly occurs. Therefore, even if the total weight is small and the thickness is small, high surface hardness and strength can be obtained. Therefore, even if it is used for a top board, a shelf board, or the like, it is possible to increase the degree of freedom in designing support members such as legs for supporting them.

In particular, the design materials PW _{D1 and} PW _D2 of the laminated plastic-worked wood LPW of the present embodiment are arranged such that the cross grain surface or chamfered surface on the front side of the wood is a pressed surface. That is, the front and back surfaces of the laminated plastic-worked wood LPW are cross grain surfaces or chamfered surfaces on the wood front side, and the cross grain surfaces or chamfered chamfer surfaces on the wood front side are pressed by a pair of press plates 10A and 10B during heat compression. It faces the press plates 10A and 10B. Therefore, since it is compressed in the compression direction where the amount of strain and internal resistance due to compression are small, even if there are many knots, crushing, breakage, cracking, etc. of the knots are unlikely to occur, and moreover, the design materials PW _{D1 and} PW _D2 are heated. It becomes possible to concentrate the compressive force and increase the surface hardness and strength of the design materials PW _{D1 and} PW _D2 . Also, the anisotropy of shrinkage is balanced between the front and back surfaces of the design materials PW _{D1 and} PW _D2 . Therefore, it is difficult to be distorted by heat compression, and even if there are knots, it is difficult to cause internal cracks, and it has high dimensional and shape stability even if the ambient environmental conditions change. Furthermore, the multilayer structure in which the inner layer material PW _I is sandwiched in parallel between the design materials PW _{D1 and} PW _D2 having a higher compression density than the inner layer material PW _I provides mechanically stable strength.

In the laminated plastically processed wood LPW obtained by laminating a plurality of wood NWs and consolidating them in this way, even if one of the design materials PW _{D1 and} PW _D2 or the inner layer material PW _I uses a material with knots, By using a knot-free material for the other of the design materials PW _{D1 and} PW _D2 , the surface design of the used surface can be maintained.

Here, according to the experimental research of the present inventors, the laminated plastically worked wood LPW of the present embodiment has an annual ring line RL appearing on the butt end surface of the design materials PW _{D1 and} PW _D2 Tree-ring angle θ _D , which is an acute-angle intersection angle with a straight-faced surface, and an acute-angle-side intersection between an annual-ring line RL appearing on the butt surface of the inner layer material PW _I and the cross-grain surface or straight-edge surface on the back side of the tree An annual ring angle θ _I that is an angle preferably satisfies θ _D <θ _I . The tree-ring angle θ _D , which is the acute-angle intersection angle formed by the tree-ring line RL appearing on the butt surface of design materials PW _{D1 and} PW _D2 and the cross-grain surface or chamfered surface of the back side of the tree, and the butt surface of the inner layer material PW _I Design materials PW D1 and PW D2 are design materials PW _{D1 and} PW _D2 that have a relationship of θ _D < θ _I between the tree ring line RL that appears and the tree ring angle θ _I that is the intersection angle on the acute angle side formed by the cross-grain surface or the straight-edge surface on the back side of the tree. Since the heat compressive force concentrates on the design materials PW _{D1 and} PW _D2 , the amount of compressive deformation of the design materials PW D1 and PW D2 is large, so high surface hardness can be obtained. In addition, the internal resistance of the wood NW _{D1 and} NW _D2 of the front and back layers during heat compression is small, the internal stress generated during heat compression is small, and the heat compression force applied to the inner layer material PW _I can be reduced, so there are many knots. In some cases, for example, when knots exist at a high occupancy of 10% to 20% and the difference in partial specific gravity is large, when there are knots penetrating the front and back surfaces of the wood NW, or when there are knots with a diameter of 20 mm or more. Even in this case, cracks such as cracks and fissures are less likely to occur at the knots and their surroundings.

Furthermore, according to the experimental research of the present inventors, the laminated plastic processed wood LPW of the present embodiment has an annual ring line RL appearing on the butt end surface of the design materials PW _{D1 and} PW _D2 The annual ring angle θ _D , which is the intersection angle on the acute angle side formed by the inner layer material PW _I , is within the range of 0° < θ _D ≤ 30°, preferably 0° < θ _D ≤ 20°. The annual ring angle θ _I , which is the angle of intersection on the acute side formed by the appearing tree ring line RL and the cross grain surface or the straightened surface of the back side of the tree, is 5° ≤ θ _I ≤ 80°, preferably 10° < θ _D ≤ 70°. is preferably within the range of Within this range, the design materials PW _D1 and PW _D2 are subjected to heating and compressive force, and the design materials PW _{D1 and} PW _D2 undergo a large amount of compression deformation, resulting in high surface hardness. In particular, the specific gravity of the surface can be made higher than the specific gravity of the whole, and lightness, surface hardness, and strength can be achieved at the same time. In addition, since the internal resistance of each wood NW during heat compression is small and the internal stress generated during heat compression is small, buckling deformation of the annual ring line RL due to heat compression is prevented, and internal cracks such as cracks and fissures are prevented. is difficult to occur. Then, when many knots exist, for example, when knots exist at a high occupancy rate of 10% to 20% and the difference in partial specific gravity is large, or when there are knots penetrating the front and back surfaces of the wood NW, Even if there are knots with a diameter of 20 mm or more, cracks and fissures are less likely to occur at the knots and their surroundings.

As for the annual ring angles θ _D and θ _I , ideally, for lumber without knots K, the intersection between all the annual ring lines RL appearing on the butt surface and the cross-grain surface or straight-line surface on the back side of the tree is This corresponds to the angles θ _D and θ _I , but it is a natural object, and in wood with a knot K, the annual ring line RL is disturbed around the knot K. For example, Where there are no knots, annual rings consisting of early wood and late wood are arcuate, but where there are knots, the knots are oriented substantially perpendicular to the length of the wood grain so as to change the flow of the annual rings. Since it strikes, it is not practically required that all tree ring lines RL appearing on the buttress surface strictly satisfy the above angle conditions. Even if there are several tenths of tree ring lines RL that are not aligned, there is no problem as long as the average value satisfies the above angle conditions.

By the way, in order to ensure the smoothness of the final product, one or both of the front and back surfaces of the laminated plastic processed wood LPW _P after consolidation are usually cut. In machining, it was found that even a difference of 0.5 to 1 mm in the amount of cutting on the surface greatly affects the hardness and strength of the cut surface.
Also, if the design materials PW _{D1 and} PW _D2 are too thin, and if a material with knots is used for the inner layer material PW _I that overlaps them, the pattern of the knots K of the design material PW _D1 is used as the surface to be used. _, may appear on the surface of PW _D2 .

Therefore, according to the earnest experimental research of the present inventors, the thickness of the design materials PW _{D1 and} PW _D2 is preferably the thickness of the inner layer material PW It is in the range of 0.3 to 0.8 times the thickness of _I , and more preferably in the range of 0.4 to 0.6 times. If the thickness is within this range, even if there are knots in the inner layer material PW _I overlaid on the design materials PW _{D1 and} PW _D2 that are used as the surface, the knots and the surroundings of the knots will be darkened or blackened. The resulting shading pattern has a thickness that does not appear on the surfaces of the design materials PW _{D1 and} PW _D2 used as the surfaces to be used, so that the surface design is good and high surface strength and hardness are obtained.

Furthermore, the laminated _plastically worked wood _LPW of the present embodiment preferably has a total thickness of 15 mm or more and 40 mm or less, more preferably 18 mm to 35 mm. The thickness is preferably 1.5 mm or more and 10 mm or less, more preferably 1.5 mm or more and 8 mm or less, and the thickness of the inner layer material PW _I is preferably 6 mm or more and 15 mm or less, more preferably is in the range of 8 mm or more and 13 mm or less. If the thicknesses of the design materials PW _{D1 and} PW _D2 are within this range, even if there are knots in the inner layer material PW _I superimposed on the design materials PW _{D1 and} PW _D2 that are used as the surfaces to be used, the knot portions K pattern is not exposed on the surfaces of the design materials PW _{D1 and} PW _D2 used as the surfaces to be used. In particular, the use of coniferous trees such as cedar and cypress ensures light weight with a thin overall thickness. Therefore, even when it is applied to a desk for children at school, an office, a desk for a dining table at home, a shelf board, or the like, it is possible to increase the degree of freedom in designing supporting members such as legs for supporting it.
Further, the design materials PW _{D1 and} PW _D2 are highly compressed and compacted so that they do not easily absorb and release moisture even if the ambient environmental conditions change.

Here, a wood NW made of cypress wood and having a thickness in the range of 12 to 15 mm was used, and the compression ratio with respect to the air-dried specific gravity of the original wood NW was in the range of 45% to 65%. Two design materials PW _{D1 and} PW _D2 on the front and back, and one inner layer material PW _I compressed at a compression ratio within the range of 10% to 40% with respect to the air dry specific gravity of the original wood NW. A laminated plastic-worked wood LPW _P was prepared by lamination and bonding, and the front and back sides thereof were cut by 2 mm to 3 mm to form a laminated plastic-worked wood LPW, and the Brinell hardness HB of the laminated plastic-worked wood LPW was measured. As for the laminated plastically worked wood LPW, a plurality of pieces having different thicknesses and compression ratios were produced by changing the thickness of the wood used and the cutting thickness, and the Brinell hardness HB of each was measured.

Specifically, the Brinell hardness HB is measured according to the test method for wood of JIS Z 2101, and a steel ball with a diameter of 10 mm is applied from one of the design materials PW _{D1 and} PW _D2 to the prepared laminated plastic processed wood LPW. is press-fitted to a depth of about 0.32 (1/π) mm at a speed of 0.5 mm/min, and the load at that time is divided by the contact area. As for the Brinell hardness, Table 1 shows the highest Brinell hardness HB among the average values measured at 12 points on each piece of wood.
For comparison, the Brinell hardness HB was similarly measured for laminated rubber timber and uncompressed cypress and oak timbers, which are used for the surface layer of the top plate of current school desks.
Table 1 shows the measurement results of these Brinell hardnesses HB.

As shown in Table 1, the laminated plastic processed wood LPW that has been subjected to a predetermined consolidation process has the highest Brinell hardness despite having a smaller specific gravity and lighter weight than laminated rubber lumber, uncompressed cypress and oak. became hard. Therefore, according to this laminated plastic processed wood LPW, lightness and high surface hardness and strength are compatible. Furthermore, it is possible to increase the degree of freedom in designing the legs that support the top board of a desk or the like, a shelf board, or the like. Therefore, it is suitable for use as a top plate of a study desk or the like for school, which requires easy carrying, writing, and resistance to scratching by a cutter or the like. In addition, laminated rubber timber, uncompressed cypress timber, and oak timber are natural timbers, so there is a large variation in characteristics such as hardness and strength, and in quality. Since hardness and strength are increased by consolidation processing, variations in characteristics such as hardness and strength and quality are suppressed, and defective products due to lack of hardness and strength are less likely to occur, increasing commercial value as a top plate. It can be made high.

Thus, the laminated plastically worked wood LPW of the present embodiment has a Brinell hardness of 15N or more and 30N or less, preferably 18N or more and 30N or less, more preferably 18N or more and 25N or less. Within this range, the surface is hard to be scratched by writing, a cutter, or the like, that is, it has a high surface hardness and strength, and is hard to break even if it has knots. In addition, wood whose surface hardness is increased by such a compaction process has the texture of wood's original wood grain and warmth. preferred.

As described above, the laminated plastically worked wood LPW according to the above embodiment is obtained by stacking three or more woods NW in the direction perpendicular to the length direction of the wood grain, and Laminated plastic-worked wood LPW formed by consolidating by heat compression in the vertical direction and integrally joining two thin design materials PW _D1 located on the front and back layers and highly compressed by heat compression. _, PW _D2 , and one or more thick inner layer materials PW _I located between the two design materials PW _{D1 and} PW _D2 of the front and back layers and having a lower compression than the design materials PW _{D1 and} PW _D2 . It is something to do.

That is, the laminated plastically worked wood LPW according to the above-described embodiment is a laminated wood LW formed by laminating a plurality of wood NWs in a direction perpendicular to the grain length direction of the wood NW, and Two design materials PW _{D1 and} PW _D2 , which are plastically worked by heat compression in the vertical direction and are integrally joined, having a large amount of compression by heat compression and a small thickness, are arranged on the front and back layers, One or more inner layer materials PW _I having a smaller compression amount due to heat compression and a greater thickness than the two design materials PW _{D1 and} PW _D2 are arranged between the two design materials PW D1 and PW _D2 . .

Therefore, according to the laminated plastic-worked lumber LPW according to the above embodiment, the design materials PW _{D1 and} PW _D2 forming the front and back design surfaces are highly compressed, while the inner layer material PW between the design materials PW _{D1 and} PW _{D2 I} is plastic processing with low compression, which can increase the mechanical strength and surface hardness compared to the original wood NW, and can be used as an internal inner layer material other than the design materials PW _{D1 and} PW _D2 on the front and back. PW _I is less compressible than the design materials PW _{D1 and} PW _D2 , and since the compression rate is balanced on the front and back, distortion due to compression is less likely to occur, so even if a material with knots is used, the It is difficult to apply a strong compressive force to the joints. In particular, it is a plastic working of a laminated wood LW in which wood NWs are piled up. Since the portion can be softened by heating and compression and can be deformed by pressing of the hard node, the portion can receive the portion with a low specific gravity. Therefore, even if there are knots, the knots K are less prone to cracks, fissures, and the like. In addition, it is assumed that the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I are laminated and joined with three or more pieces of wood, and a material with knots is used for the inner layer material PW _I and one of the design materials PW _{D1 and} PW _D2 . However, if a knotless material is used for the other design materials PW _{D1 and} PW _D2 , it is possible to maintain the design in terms of use.

In addition, according to the laminated plastically processed lumber LPW according to the above embodiment, a plurality of lumbers NW are laminated and consolidated to obtain a thickness of one lumber. Since it may be thin, it is possible to shorten the drying time in the drying process before consolidation and reduce the load due to drying. Therefore, even when a material with knots is used, it is possible to prevent knot cracking and knot dropout due to drying, and to improve the yield.

In addition, according to the laminated plastically worked wood LPW according to the above embodiment, the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I are integrally joined to each other, so distortion and warping due to expansion and contraction after commercialization It is possible to prevent peeling at the joint surface due to the occurrence of .

In this way, according to the laminated plastically worked wood LPW according to the above embodiment, even if there are knots in the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I , cracks such as cracks and fissures are unlikely to occur at the knots K. In addition, it is possible to achieve both designability and effective use of materials with knots.

In particular, according to the laminated plastically worked wood LPW according to the above-described embodiment, the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I are laminated with the grain length direction aligned with each other, so that the knots Even when a certain material is used, the knots tend to press against the wood structure of the opposing laminated material during heat compression, and compressive stress is less likely to be applied to the knots. Therefore, when there are many knots, for example, when knots exist at a high occupancy of 10% to 20% and the difference in partial specific gravity is large, when there are knots penetrating the front and back of the wood, or when the diameter is 20 mm or more Even if there are knots, it is difficult to cause cracks, fissures, etc. at the knots and their surroundings. Therefore, it is possible to further improve the yield during plastic working.

In addition, in the laminated plastically worked wood LPW according to the above embodiment, each of the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I have the annual ring line RL appearing on the butt end surface of the design materials PW _{D1 and} PW _D2 and the plate on the back side of the wood. Acute angle of annual ring θ _D at which the grain surface or the straight edge surface intersects, and acute angle θ _I at which the annual ring line RL appearing on the butt surface of the inner layer material PW _I intersects with the cross grain surface or the straight edge surface of the back side of the tree. When .theta..sub.D < _.theta.I , the design materials _{PW.sub.D1 and PW.sub.D2} have a large amount of compressive deformation and a small internal stress during heating and compression. Therefore, the strain due to compression is small, and even if there are knots, cracks and cracks do not occur, and a high surface hardness can be obtained.

Furthermore, in the laminated plastically processed lumber LPW according to the above embodiment, each of the design materials PW _{D1 and} PW _D2 has an acute-angled side where the annual ring line RL appearing on the butt end surface intersects with the cross grain surface or the chamfer surface on the back side of the tree. The annual ring angle θ _D is 0° < θ _D ≤ 30°, and one or more inner layer materials PW _I are divided between the annual ring line RL appearing on the butt surface and the cross grain surface or the straightening surface on the back side of the tree. When the annual ring angle θ _I on the acute angle side where the two intersect is 5°≦θ _I ≦80°, buckling deformation of the annual rings due to thermal compression is small. Therefore, even if there are knots, cracks are unlikely to occur inside the wood, and distortions are unlikely to occur. Therefore, it is possible to stabilize the quality.

In addition, according to the laminated plastically worked wood LPW according to the above embodiment, each of the design materials PW _{D1 and} PW _D2 is arranged such that the cross grain surface or the chamfered surface on the front side of the wood is a pressed surface, so that the compression It is compressed in the direction of compression where the amount of strain and internal resistance due to is small. In addition, since the front and back surfaces of the laminated plastic-worked wood LPW are on the front and back surfaces of the design materials PW _{D1 and} PW _D2 , the anisotropy of shrinkage is well-balanced. Therefore, even if there are knots, internal cracks are unlikely to occur, and the dimensional shape stability is high.

In the laminated plastically processed lumber according to the above embodiment, if the air-dried specific gravity is 1.2 times or more and 1.7 times or less than the air-dried specific gravity of the original lumber, surface hardness, strength and lightness are achieved. make it possible to achieve both

In particular, according to the laminated plastic-worked wood LPW according to the above embodiment, the design materials PW _{D1 and} PW _D2 can be compressed by heating to achieve a compression rate within the range of 45% to 65% with respect to the air-dried specific gravity of the original wood NW. The compression rate of the inner layer material PW _I is within the range of 10% to 40% in terms of compression rate with respect to the air-dried specific gravity of the original wood NW by heat compression, so it is high even if it is lightweight using softwood. Surface hardness is obtained. Therefore, both lightness and high surface hardness can be achieved.

In addition, in the laminated plastically worked wood LPW according to the above embodiment, if the thickness of the design materials PW _{D1 and} PW _D2 is within the range of 0.3 to 0.8 times the thickness of the inner layer material PW _I , use Even if there is a knot K in the inner layer material PW _I overlaid on one of the design materials PW _{D1 and} PW _D2 , which is the face side, the darker and blacker pattern around the knot and the knot is the design of the used side. The thickness is such that it does not appear on the materials PW _{D1 and} PW _D2 , and the surface hardness can be increased. Therefore, it is possible to achieve both surface hardness/strength and surface design.

Furthermore, in the laminated plastically worked wood LPW according to the above embodiment, the overall thickness is in the range of 15 mm or more and 40 mm or less, and the thickness of the design materials PW _{D1 and} PW _D2 is in the range of 1.5 mm or more and 10 mm or less. In the case where the thickness of the _inner layer material _{PW I} is within the range of 6 mm or more and 15 mm or less, the _knot K Even if there is a knot and a darkened or blackened pattern around the knot, the thickness is such that it does not appear on the design materials PW _{D1 and} PW _D2 that are used on the side of use, and the overall thickness is thin and lightweight. , high surface hardness is ensured. Therefore, it is possible to achieve both surface hardness/strength, surface design and light weight.

In the laminated plastically worked wood LPW according to the above embodiment, if the Brinell hardness is in the range of 15 N or more and 30 N or less, the surface hardness is such that shallow and fine scratches are difficult to be caused by writing, cutters, etc. It is also suitable as a top board for school children's desks, home study desks, office work desks, dining table desks, and the like.

In the laminated plastically worked wood LPW according to the above embodiment, one or more of the facing surfaces of the design materials PW _D1 , PW _D2 and the inner layer material PW _I are provided with a convex portion P by the knot K and a knot K Even if there is a joint surface BF with a deformed concave portion D, the movement of the joint is not restricted or restrained due to the softening and deformation of the wood structure around it, and cracks such as cracks and fissures occur at the joint K. It is compacted without entering. Therefore, the use of knotted material is less expensive. In addition, wood with knots is difficult to compress and resists compression, so it is possible to increase the surface hardness.

By the way, in the case of forming a product such as a predetermined wide or long top board or shelf board, a plurality of laminated plastic processed lumber LPWs are arranged in parallel with the length direction of the wood grain, and are arranged in the thickness direction. In the vertical direction of the width, that is, in the horizontal direction, and jointed horizontally to have a predetermined width, or in the length direction of the wood grain, that is, in the longitudinal direction, a plurality of laminated plastic-worked lumber LPWs are connected. It is possible to form a predetermined length dimension by splicing and splicing. At this time, a plurality of laminated lumber LW before processing may be jointed horizontally in the width direction perpendicular to the length direction of the grain and/or may be vertically jointed in the length direction of the wood grain for consolidation. good. Laminated plastic processed wood LPW has moisture absorption and desorption characteristics when the ambient environmental conditions change due to the presence of the design materials PW _D1 and PW _D2 that are highly compressed, that is, there is little change in expansion and contraction, and the dimensional shape stability is improved. Therefore, even if a plurality of laminated plastic-worked lumber LPWs are jointed horizontally or longitudinally, a load is applied to the joint surfaces due to changes in ambient environmental conditions, and cracks and distortions are unlikely to occur. In addition, since a large stress is less likely to occur due to changes in ambient environmental conditions, cracks, distortions, etc. of the wood are less likely to occur even when the knots K are present.

By the way, since there is an abundant resin content in the knots and their surroundings, there is a risk that resin will precipitate when excessive heat compression force is applied there, but the lamination plastic working of the above embodiment According to the wood LPW, excessive stress does not easily enter the knots K, so that a large amount of tar deposits from the knots K can be suppressed. Therefore, even if there is a knot K, there is no fear that the resin from the knot K will adhere to the press platen 10 or the like used for heat compression and contaminate the pair of press plates 10, and the laminated plastic processed lumber after the compaction process. A situation in which the LPW cannot be separated from the pair of press plates 10 does not occur. In addition, since the knots K are not highly compressed, there is no chance that a large amount of tar will deposit from the knots K when the ambient environmental conditions change after commercialization, resulting in a decrease in commercial value.

In the above-described embodiment, heat compression is performed by surface contact between the upper press platen 10A and the lower press platen 10B. Since there are few backtrackings, we can stably provide high-quality products.
However, when carrying out the present invention, the consolidation process is not limited to the manufacturing method described above, and may be, for example, manufacturing using compression rollers or rolling rolls.

Since the plastically worked wood PW of the present embodiment has high surface hardness and strength, it also has high wear resistance and impact resistance, and is suitable for uses other than top boards and shelf boards. That is, it can be applied not only to desk tops and shelf boards such as school desks, children's desks, and dining tables, but also to furniture, kitchen boards, stair boards, floors, decks, waistboards, and the like.
It should be noted that the numerical values given in the embodiments of the present invention do not indicate critical values, but indicate preferred values suitable for implementation, so even if the above numerical values are slightly changed, the implementation is denied. is not.

LPW Laminated plastic processed wood NW _D1 , NW _D2 , NW _I1 , NW _I2 , NW _I3 Wood before processing PW _D1, PW _D2 Design material PW _I1 , PW _I2 , PW _{I3 Inner} layer material RL Annual ring line Convex part P
Concave part Q
Joint surface BF

In the present invention, for example, a laminated lumber made by laminating a plurality of soft lumbers such as cypress and cedar is subjected to compaction by applying a compressive force in a direction perpendicular to the length direction of the wood grain, and The present invention relates to a laminated plastic-processed lumber that is integrally joined, and particularly to a laminated plastic-processed lumber that can increase the mechanical strength without causing cracks, fissures, etc., even when knots are present. .

In recent years, the problem of global warming, that is, the increase in the amount of carbon dioxide, which is a greenhouse gas, has become a concern, and wood is expected to absorb and fix carbon dioxide, so wood is used for buildings and furniture. It is said that this will promote deforestation and circulation of forests, thereby contributing to the prevention of global warming. For example, the Ministry of Education, Culture, Sports, Science and Technology (MEXT) recommends using local materials for school furniture such as children's desks. In particular, if domestically produced wood or local wood is used, the amount of carbon dioxide generated during transportation can be reduced, leading to the conservation of domestic forests.

Here, about 40% of the forests in Japan are artificial forests, of which conifers such as cedar and cypress account for more than half. The wood is relatively stable and easy to obtain.
However, conifers such as Japanese cedar and Japanese cypress are soft and have low strength and hardness.

On the other hand, Japan imports a lot of timber from foreign countries, and the demand for domestic timber has fallen sharply. There is a status quo. Forest care, for example, if pruning is not done at the right time, the tree will sprout and become knotty. In particular, conifers such as cedar and cypress have more knots than broad-leaved trees that have been used for conventional plywood.

Therefore, when using domestic wood or local wood, it is preferable to be able to use materials with knots from the cost point of view. That is, materials with few knots are obtained from trees that have been pruned or otherwise trimmed to produce them, and wood with few knots is generally obtained from logs such as side boards that have been removed from posts. Since it can only be collected from a part of the forest, it is a valuable and high-value-added material, and is inevitably expensive. In particular, in light of the current situation where forests that are under-maintained are increasing, it is predicted that the price of materials with few knots will rise further in the future. On the other hand, materials with knots can be procured inexpensively. Therefore, there is a demand for effective utilization of knotted materials.
However, materials with knots tend to have twisted or bent fibers running around the knots, and therefore have problems of poor workability and inferior strength compared to materials with few knots.

Here, as disclosed in Patent Document 1, the present inventors have previously established a technology that can improve the strength characteristics of even soft wood such as cedar by compressing it to increase its density. is doing.
In Patent Document 1, by heating and compressing a piece of wood in a direction perpendicular to the length direction of the wood grain to compress the density distribution of the entire thickness to a predetermined value, even if there are knots, cracks (cracks, fissures) It discloses the technology to make wood without wood.

Japanese Patent No. 6450489

However, depending on the degree of knots in the product of plastically processed lumber with knots that have been subjected to compaction, the knots may appear on the outer surface, and this may not be aesthetically pleasing to users. Especially in furniture with a small wooden area, the presence of knots can be a decisive factor in purchasing because the position, shade, pattern, etc. of the knots greatly affect the design and aesthetics of the wood product. For this reason, there has been a demand for a product that does not stand out even if wood with knots is used.
In addition, in the technique of Patent Document 1, a thick piece of lumber is compacted and commercialized as a floor material or the like. During the drying process, knot cracks and knot dropouts may occur, making it difficult to ensure a high yield.

Therefore, the present invention provides a laminated plastically processed lumber that is resistant to cracks, fissures, etc., even if the lumber has knots, can achieve both designability, and can effectively utilize materials with knots. The challenge is to provide

The laminated plastically processed lumber of claim 1 is obtained by laminating three or more lumbers in a direction perpendicular to the length direction of the wood grain, and heating and compressing the lumber in a direction perpendicular to the length direction of the wood grain. A laminated plastic-processed lumber obtained by consolidating and integrally joining two design materials of front and back layers that are highly compressed by the heat compression and have a high density and a thin thickness, and two sheets of the front and back layers. and one or more inner layer materials having a low density and a thickness, which are sandwiched between the design materials and have a lower compression than the design materials.

Here, the three or more pieces of wood are laminated in the direction perpendicular to the length direction of the wood grain, subjected to compression processing by heat compression in the direction perpendicular to the length direction of the wood grain, and integrally joined. Ternaru is a laminated material made by stacking three or more pieces of wood in the direction perpendicular to the length direction of the wood grain. It means that it is a product obtained by compression molding and consolidation processing, and by applying adhesive etc. between the woods in advance and laminating the laminated material, heat compressing and consolidating the adhesive simultaneously with the heat compression of the consolidation processing. It may be one in which the laminated woods are joined together by curing or the like. A laminated material formed by laminating wood without any intervening material may be heat-compressed and compacted, and then integrally laminated and adhered. Note that the above-mentioned lamination in a direction perpendicular to the length direction of the wood grain means lamination on a surface perpendicular to the length direction of the wood grain, that is, on a surface other than the end surface and the end surface, and the number of layers is 3. The number of sheets may be at least as long as it is an odd number or an even number.

In addition, the heat compression in the direction perpendicular to the length direction of the wood grain (tree direction, tree direction) refers to the direction of the fiber of the annual ring It means that the area of the butt end surface of the wood is reduced by heat compression by applying an external force using a press or the like in the direction perpendicular to the direction of the tree. Normally, in the case of cross-grain lumber, considering the amount of strain due to compression, the area of the butt end surface of the wood is reduced by applying press compression to the cross-grain side of the wood. It is also possible to determine whether to press-compress the surface side or the straight-grained surface side, depending on the type of lumber or the like.

The cross-grain surface is a wood surface cut in the longitudinal direction of the wood grain, that is, parallel to the fiber direction of the annual ring and cut in the tangential direction of the annual ring line. In addition, the above-mentioned wood surface is a surface cut in a direction crossing the fiber direction of the annual rings of the wood, that is, a surface cut perpendicularly or obliquely to the length direction of the grain of the wood. is. Further, the straight-grained surface is a wood surface cut in the radial direction (radial direction) of the annual ring line parallel to the fiber direction of the annual rings of the wood. In addition, the above-mentioned oisama (also referred to as nagashisama or hansama) is an intermediate wood grain or wood grain between straight grain and cross grain.

The two design materials are the outer layers of the front and back of the wood that is laminated and joined, that is, the two woods of the surface layer and the back layer, and both are highly compressed than the inner layer material interposed between the design materials. In other words, the amount of compressive deformation of the cells is large and the density is increased. .
The one or more inner layer materials are interposed between the two design materials, which are the surface layer and the back layer, of the laminated and joined wood, and are compressed lower than the design materials, so that the amount of compressive deformation of the cells is small. It has a low density and a large thickness. The inner layer material may be one, or a plurality of two or more, preferably one to three. Determined by the type of wood, etc.

The design material and the inner layer material are laminated and joined in the order of one design material, one or more inner layer materials, and the other design material in the direction perpendicular to the length direction of the wood grain. Boundaries of wood from each other can be distinguished from each other by fine quality lines or by changes in tree ring lines on the butt surface. The design material and the inner layer material are laminated in the thickness direction that is perpendicular to the length direction of the grain of each wood, that is, in the surface other than the end surface and the end surface, and the design of the front and back layers Regarding the material, it does not specify the usage direction of the front and back surfaces. Moreover, the design material and the inner layer material may be laminated with the length of the wood grain matched with each other, or may be laminated in a direction orthogonal to the length direction of the wood grain. Furthermore, it does not matter whether or not each piece of wood has knots, and naturally even wood without knots can be used.
Here, the above-mentioned thickness means the thickness in the direction perpendicular to the grain length direction of the wood, and since there may be cases where the joint surfaces are not uniform at places where the difference in specific gravity between the facing woods is large, the average thickness is used. compared to In the laminated plastic processed lumber, the front and back surfaces are usually cut after consolidation in order to ensure smoothness, so this corresponds to the thickness after cutting.

The species of wood is not particularly limited, and may be either a coniferous tree or a broadleaf tree. For example, cedar, cypress, pine (larch, Sakhalin fir, Ezo spruce, Japanese red pine, etc.), Japanese sawara, walnut (walnut), yellow poplar, Italian poplar, mominoki, hemlock, spruce, yew, asunaro, paulownia, hiba, birch, itajii, karin , falcata, gmelina, chinaberry, tulip tree, etc. are used. In particular, Japanese cedar and cypress wood are widely distributed in Japan, and thinned wood can be easily obtained in large quantities, so that they can contribute to environmental conservation. In addition, cedar and cypress, which are conifers, have a high porosity in the wood structure, so the thermal conductivity is low, and the warmth is strongly felt when touched.

Each design material of the laminated plastically processed lumber of the invention of claim 1 has a thickness of 0.3 to 0.8 times the thickness of the one inner layer material or two or more inner layer materials, Preferably, it is within the range of 0.4 times to 0.6 times.
The above thickness is the average thickness because there are cases where the heating and compression are not necessarily uniform at a location where the specific gravity difference between the facing woods is large.

Each of the design materials of the laminated plastic-processed lumber of the invention of claim 1 has a compressibility of 45% to 65%, preferably 50% to 60%, relative to the air-dry specific gravity of the original lumber by the heat compression. The compressibility is 15% to 42%, preferably 20 to 40%, with respect to the air dry specific gravity of the original wood by the heat compression of the one inner layer material or the two or more inner layer materials. The compression rate is within the range.
Here, the compression rate with respect to the air-dried specific gravity of the original wood is calculated from the air-dried specific gravity of the original wood and the air-dried specific gravity of each design material and inner layer material, and is obtained from the following formula. It is.
Compression ratio <%>
= [1-[(air-dried specific gravity of original wood) / (air-dried specific gravity of design material or inner layer material)]]
×100
The air-dried specific gravities of the design material and the inner layer material can be measured by cutting off the individual lumbers of the design material and the inner layer material that are joined to each other at their joint surfaces.

The design material and the inner layer material of the laminated plastically worked lumber of the invention of claim 2 are laminated with the length direction of the wood grain aligned with each other.

Each of the design materials of the laminated plastically processed lumber of the invention of claim 3 has a cross-grain surface or chamfered surface on the wood surface side as a pressed surface.
The above-mentioned cross-grain surface or chamfered surface on the wood surface side means that the cross-grain surface or chamfered surface on the wood surface side is positioned on the front and back surfaces of the heat-compressed laminated plastic processed lumber. That is, the laminated wood is arranged so that the cross grain surface or the chamfered surface on the front side of the wood is positioned on the front and back surfaces, and the press machine that heats and compresses is in contact with the cross grain surface or the chamfered surface on the wood surface side. It means that it was pressed from the cross grain side or the straight side of the wood front side. In addition, the "wood surface" refers to the cross-grain surface or the oishaku surface closer to the bark when viewed from the butt end surface. In addition, the side of the tree that is closer to the core, the center of the annual rings on the opposite side of the tree surface, is called the "back of the tree."

The laminated plastic processed lumber of the invention of claim 4 has an air-dried specific gravity of 1.2 times or more and 1.7 times or less, preferably 1.3 times or more and 1.6 times that of the original wood. It is within the following range.
The above-mentioned air-dried specific gravity is the specific gravity when the wood is dried in the air, that is, when it reaches the air-dried moisture content, and is usually expressed by the specific gravity when the moisture content is 15%. It is a value that compares the weight of the same volume of water with the weight of the water. A larger number means heavier, and a smaller number means lighter.

The design material and the inner layer material of the laminated plastic processed lumber of the invention of claim 5 are the growth rings on the acute angle side where the annual ring line appearing on the butt surface of each of the design materials intersects with the cross grain surface or the chamfer surface on the back side of the tree. The angle θ _D and the annual ring angle θ _I on the acute angle side where the tree ring line appearing on the butt surface of the inner layer timber or two or more inner layer timbers and the cross grain surface or the straight surface of the back side of the tree intersect. , θ _D <θ _I .
The tree-ring line on the butt surface means a linear portion in which the texture is densely formed when viewed from the butt surface, and is a wood grain appearing on the butt surface.
Here, wood is a natural product, and especially when knots are present, the flow of tree ring lines on the butt surface does not necessarily become regular. It is not required that the annual ring angles θ _D , θ _I , which are the crossing angles with the cross-grain surface or the straight surface, satisfy θ _D < θ _I , and the annual ring angles θ _D , θ of the plurality of tree-ring lines of the butt surface are not required. It suffices if the average of _I satisfies θ _D <θ _I .

In each of the design materials of the laminated plastic processed lumber of the invention of claim 6, the annual ring angle θ _D on the acute angle side where the tree ring line appearing on the butt end surface and the cross grain surface or chamfer surface on the back side of the tree intersect is 0°<θ _D≤30 °, preferably 0°<θ _I ≤25° Alternatively, the angle θ _I on the acute angle side where it intersects with the chamfered surface is 5°≦θ _I ≦80°, preferably 10°≦θ _I ≦70°.
Here, wood is a natural product, and especially when knots are present, the flow of tree ring lines on the butt surface is not always regular. It is not required that all of the tree-ring angles θ _D and θ _I , which are the angles of intersection with the cross-grain surface or the chamfered surface, are within the above numerical range, and multiple tree-ring angles θ _D , θ of the butt surface of each lumber. It is sufficient if the average of θ _I is within the above numerical range.

The laminated plastically processed lumber of the invention of claim 7 has an overall thickness of 15 mm or more and 40 mm or less, preferably 18 mm or more and 35 mm or less, and each design material has a thickness of 1.5 mm or more and 10 mm. Below, it is preferably in the range of 1.5 mm or more and 8 mm or less, and the thickness of the one inner layer material or each of the two or more inner layer materials is 6 mm or more and 15 mm or less, preferably 8 mm or more and 13 mm or less. is within the range of
Note that the above thickness may not necessarily be uniform at locations where there is a large difference in specific gravity between facing wood pieces, so the thickness is taken as an average thickness.

The laminated plastically worked lumber of the invention of claim 8 has a Brinell hardness of 15N or more and 30N or less, preferably 18N or more and 30N or less, more preferably 18N or more and 25N or less.
The Brinell hardness (HB) conforms to the wood test method of JIS Z 2101, and a steel ball with a diameter of 10 mm is cast from one design material side of the laminated plastic processed wood at a speed of 0.5 mm per minute to a depth of about 0. It was obtained by dividing the indentation load when the material was press-fitted up to 0.32 (1/π) mm by the surface area of the dent remaining after the load was removed. Note that wood is a natural product, and since there is a difference in hardness between early wood and late wood, the average of measurements at 12 arbitrary locations is used here.

In one or more of the facing surfaces of the design material and the inner layer material of the laminated plastically processed lumber of the ninth aspect of the invention, there are convex portions formed by knots and concave portions deformed by pressing by the knots. It has a joint surface.
The joint surface formed by the convex portion formed by the knot portion and the concave portion deformed by the pressure applied by the knot portion means a joint surface having undulations in the joint between the pieces of wood. That is, when heated and compressed, the hard knot of one piece of wood presses the opposing portion of the other piece of wood stacked thereon and is deformed, thereby forming a convex portion and knot portion on the joint surface between the joined pieces of wood. It means that there are undulations that are formed by facing the recessed parts formed by deformation pushed into the wood. do.

The laminated plastic processed lumber according to the invention of claim 1 is a laminated lumber obtained by laminating a plurality of lumbers in a direction perpendicular to the length direction of the grain of the lumber. Two design materials having a large amount of compression by the heat compression and a small thickness are arranged on the front and back layers, and the two sheets of the front and back layers are arranged. One or more inner layer materials having a smaller compression amount and a greater thickness than the design material are disposed between the two design materials.

According to the laminated plastically processed lumber of the invention of claim 1, while the design materials forming the front and back design surfaces are highly compressed, the inner layer material interposed between the design materials is plastically processed with low compression. In addition to being able to increase the mechanical strength and surface hardness compared to the wood of the front and back, the inner layer material interposed between the front and back design materials has a lower compression than the design material. By balancing the compressibility, strain due to compression is less likely to occur, so even if a material with knots is used, a strong compressive force is less likely to be applied to the knots. In particular, it is a plastic processing of laminated wood, and even if the wood has knots and there are hard parts with different specific gravities, the hard knots with high specific gravities cannot be obtained by stacking the wood and compressing it under heat. However, the low specific gravity part of the wood layered on it is softened by heat compression and deformed by the pressure of the hard knots, so that the movement of the knots is not restricted, so excessive compressive stress and internal stress are difficult to apply to the knots. . Therefore, even if there are knots, cracks, fissures, and the like are less likely to occur. In addition, since it is made by laminating and joining multiple pieces of wood, even if a material with knots is used for the inner layer material or one of the design materials, it can be used if a material without knots is used for the other design material, which is the surface to be used. In terms of surface design, it is also possible to maintain design.

In addition, according to the laminated plastically processed lumber of the invention of claim 1, a plurality of lumbers are laminated, joined and consolidated to produce a single thickness, and the thickness of each lumber of the raw material is thin. Therefore, it is possible to shorten the drying time in the drying process before consolidation and reduce the drying load. Therefore, even when a material having knots is used, it is possible to prevent knot cracking and knot dropout due to drying, thereby improving the yield.

According to the laminated plastic-processed lumber according to the first aspect of the invention, each of the design materials has a thickness of 0.3 to 0.3 to the thickness of the one inner layer material or each of the two or more inner layer materials. It is within the range of 8 times. If the thickness of the design material is within the range of 0.3 to 0.8 times the thickness of the inner layer material even after compression processing, the inner layer material superimposed on the design material on the use side has knots. Even in such a case, the thickness is such that the knots and darkened and blackened patterns around the knots do not appear on the design material to be used, and the surface hardness can be increased. Therefore , it is possible to achieve both surface strength, hardness, and surface design.

According to the laminated plastically processed lumber according to the invention of claim 1 , the design material has a compression rate within a range of 50% to 60% with respect to the air-dried specific gravity of the original lumber by the heat compression, and the The inner layer material has a compressibility of 20% to 40% with respect to the air-dried specific gravity of the original wood by the heat compression. Therefore , both lightness and high surface hardness can be achieved.

In this way, according to the laminated plastically processed lumber of the invention of claim 1, even if the lumber has knots, it is difficult to cause cracks such as cracks, cracks, etc. It can be utilized.

According to the laminated plastic processed lumber according to the second aspect of the invention, since the design material and the inner layer material are laminated with the wood grain length direction aligned with each other, when using a material with knots However, the knots tend to press against the laminated wood structure of the opposing material during heat compression, and compressive stress is less likely to be applied to the knots. Therefore, even if there are many knots, knots penetrating the front and back of the wood, or knots with a diameter of 20 mm or more, cracks and cracks at the knots and their surroundings are unlikely to occur. It is. Therefore, in addition to the effect described in claim 1, it is possible to further improve the yield of plastic working.

According to the laminated plastic processed lumber according to the invention of claim 3, each of the design materials has a press surface on the cross grain surface or the chamfered surface side of the wood front side, so the amount of strain due to compression and the internal resistance are reduced. Compressed in the direction of less compression. In addition, the anisotropy of shrinkage is balanced because the cross-grained surface or chamfered surface on the front side of each design material is placed on the front and back surfaces of the laminated plastic processed lumber. Therefore, in addition to the effects described in claim 1 or claim 2, internal cracks and distortions of wood are less likely to occur, and dimensional shape stability is also high.

According to the laminated plastic processed lumber according to the invention of claim 4, the air-dried specific gravity thereof is 1.2 times or more and 1.7 times or less that of the original lumber. In addition to the effect described in any one of 1. above, it is possible to achieve both surface hardness, strength and lightness.

According to the laminated plastically processed lumber according to the invention of claim 5, the design material and the inner layer material are formed at an acute angle where the annual ring line appearing on the butt surface of the design material and the cross grain surface or the chamfer surface on the back side of the tree intersect. and the tree ring angle θ _I on the acute angle side where the tree ring line appearing on the butt surface of the inner layer material intersects with the cross grain surface or the _{straight surface of the back side of the tree, θ D <} θ _I. . When the design material and the inner layer material have a relationship of θ _D <θ _I in annual ring angle, the amount of compressive deformation of the design material is large, and internal stress is less likely to occur during heat compression. Therefore, in addition to the effect described in any one of claims 1 to 4, it is possible to increase the surface hardness without causing cracks, fissures, and other fractures even if there are knots.

According to the laminated plastic processed lumber according to the invention of claim 6, the design material has an annual ring angle θ _D of 0 on the acute angle side where the annual ring line appearing on the butt end surface intersects with the cross grain surface or the chamfered surface of the back side of the tree. ° < θ _D ≤ 30°, and in the inner layer material, the angle θ _I on the acute angle side where the annual ring line appearing on the butt surface intersects with the cross grain surface or the straight surface of the back side of the tree is 5° ≤ θ _I ≤ Since the angle is 80°, the buckling deformation of annual rings during heat compression is small. Therefore, even if knots are present, cracks are unlikely to occur inside the lumber, and distortion and the like are unlikely to occur. Therefore, in addition to the effect described in any one of claims 1 to 5, it is possible to stabilize the quality.

According to the laminated plastic-worked lumber according to the invention of claim 7 , the total thickness of the laminated plastic-worked lumber is within a range of 15 mm or more and 40 mm or less, and the thickness of each design material is 1.5 mm or more, The thickness of the inner layer material is within the range of 10 mm or less, and the thickness of the one inner layer material or each of the two or more inner layer materials is within the range of 6 mm or more and 15 mm or less, so the inner layer material overlaid on the design material on the use side Even if there is a knot, the thickness is such that the knot and the darkened and blackened pattern around the knot do not appear on the design material on the side of use, and the overall thickness is thin and lightweight, but the surface hardness is ensured. Therefore, in addition to the effect described in any one of claims 1 to 6 , it is possible to achieve both surface hardness/strength, surface design and lightness.

According to the laminated plastically processed lumber according to the eighth aspect of the invention, since the Brinell hardness is within the range of 15 N or more and 30 N or less, the surface hardness is such that shallow and fine scratches due to writing, cutters, etc. are unlikely to occur. Therefore, in addition to the effect described in any one of claims 1 to 7 , it is also suitable for use as a desk for children at school, an office, a table top for a dining table, and the like.

According to the laminated plastically processed lumber according to the ninth aspect of the invention, at least one of the facing surfaces of the design material and the inner layer material has a convex portion formed by a knot portion and a concave shape deformed by pressing by the knot portion. In addition to the effects described in any one of claims 1 to 8 , the use of a knotted material reduces the cost.

FIG. 1(a) is an explanatory view using three lumbers as an example of the laminated plastic processed lumber according to the embodiment of the present invention, and FIG. 1(b) shows the three lumbers of FIG. FIG. 1(c) is an explanatory diagram of a laminated laminated lumber, and FIG. 1(c) is an explanatory diagram of a laminated plastic-processed lumber according to an embodiment of the present invention, in which the laminated lumber of FIG. 1(b) is consolidated and joined together It is an explanatory diagram of FIG. 2(a) is an explanatory view using four lumbers as an example of laminated plastic processed lumber according to the embodiment of the present invention, and FIG. 2(b) shows the four lumbers of FIG. FIG. 2(c) is an explanatory diagram of a laminated lumber laminated on a specific surface, and FIG. 2(c) is an explanatory diagram of a laminated plastic-processed lumber according to an embodiment of the present invention, in which the laminated lumber of FIG. 2(b) is subjected to consolidation processing. and are integrally joined together. FIG. 3(a) is an explanatory view using four lumbers as an example of the laminated plastic processed lumber according to the embodiment of the present invention, and FIG. 3(b) shows the four lumbers of FIG. Fig. 3(c) is an explanatory view of laminated plastic-worked lumber according to an embodiment of the present invention; Fig. 3(b) 1 is an explanatory view of consolidating and integrally joining the laminated materials of FIG. FIG. 4(a) is an explanatory view using five lumbers as an example of laminated plastic processed lumber according to the embodiment of the present invention, and FIG. 4(b) shows four lumbers of FIG. FIG. 4(c) is an explanatory diagram of a laminated lumber laminated on a specific surface, and FIG. 4(c) is an explanatory diagram of a laminated plastic-worked lumber according to an embodiment of the present invention, in which the laminated lumber of FIG. 4(b) is subjected to consolidation processing; and are integrally joined together. FIG. 5 is a cross-sectional view of a schematic configuration showing an example of a plastic-worked lumber manufacturing apparatus for forming a laminated plastic-worked lumber according to an embodiment of the present invention. FIG. 6 is an explanatory diagram for explaining an example of the manufacturing process of the laminated plastically worked lumber according to the embodiment of the present invention, (a) is an explanatory diagram of the feeding of the laminated lumber to be plastically worked, and (b) is a heat compression. Explanatory drawing of the starting state, (c) is an explanatory drawing of the heating and compression state in the sealed state, (d) is an explanatory drawing of the vapor pressure control process in the sealed state, and (e) is an explanatory drawing of the cooling state in the sealed state. , (f) are explanatory diagrams of taking out the laminated plastic-worked lumber. FIG. 7 is an enlarged explanatory view of the butt end surface of the laminated plastic-worked lumber according to the embodiment of the present invention shown in FIG. 1(c).

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7. FIG.
In addition, in the present embodiment, the same symbols and the same reference numerals mean the same or corresponding parts and functions, so duplicate descriptions will be omitted here.

First, it will be explained that the lumber NW before processing, which is the raw material for the laminated plastically worked lumber LPW according to the embodiment of the present invention, is milled in advance to a predetermined size.
The thickness, width, and length of the wood NW before processing differ depending on the application, purpose, etc. of the laminated plastically processed wood LPW obtained by laminating and consolidating the wood NW. Cubical or cuboid timbers, lumber made as planks are used. Preferably, timbers NW that have been sawn as cross-grain timbers or chamfered timbers are used. It should be noted that cross-grain lumber is lumber that has been sawed in the tangential direction of the annual rings of the raw wood, that is, cross-grained lumber. It is an intermediate kidori timber that is sawed in the tangential direction of the cross grain. A cross-grained lumber usually has a butt surface (two surfaces), a cross-grain surface (two surfaces, front and back), and a straight-grain surface (two surfaces) cut along a cross section perpendicular to the fiber direction of annual rings. In the case of straightened timber, the edge surface (two sides) cut in a cross section perpendicular to the fiber direction of the wood, the straightened side of the wood grain between the cross grain and the straight grain (two sides of the front and back of the wood) ), and has straight-grained surfaces (two surfaces). Note that FIGS. 1 to 4 will be described with an example of a cross-grain material.

Regarding the wood NW used as the raw material for the laminated plastic processed wood LPW, it does not matter whether it is sapwood (sapwood, white) or heartwood (red), but in general, in conifers such as cedar, the amount of tar is Where there is a large amount of sapwood, the amount of sapwood exposed by heating and compression is small compared to that of the heartwood. In addition, since the sapwood has a brighter color than the heartwood, the change in dark color when compacted is suppressed more than the heartwood, and a good appearance is maintained. In addition, the wood NW, which is used as the raw material for laminated plastic processed wood LPW, cannot be used in the state of a log because it falls down or cracks due to natural disasters such as thinned wood, wind damage, water damage, snow damage, forest fire, frost damage, and insect damage. Damaged wood, offcuts, etc. may also be used. Cost reduction can be achieved, and environmental beautification can also be contributed.

The lumber NW, which has been lumbered to a predetermined thickness, is dried to a moisture content below the fiber saturation point before being subjected to a predetermined consolidation process using a plastic-worked lumber manufacturing apparatus 100 shown in FIGS. 5 and 6 described later. be. The fiber is once dried so that the moisture content is below the fiber saturation point, preferably below the air-dried state, to give strength, and the subsequent heat compression can cause a sufficient chemical change. The moisture content of wood is the ratio of the weight of moisture to the weight of wood not containing moisture (total dry weight, dry base), and can be measured using a measuring instrument such as a high-frequency moisture content meter. In general, since moisture evaporates from the surface side of the wood, the moisture content of the wood decreases as it gets closer to the surface, but the moisture content here indicates the value measured as the moisture content of the entire wood. .

The wood NW can be dried to a desired moisture content by a known drying apparatus, for example, an artificial dryer with a built-in refrigerator or the like using known high-temperature steam as a heat source under predetermined conditions. At this time, the overall moisture content of the wood NW is measured in advance, and the moisture content at this time, the tree species of the wood NW, the thickness, etc. are used as parameters, and a drying device such as an artificial dryer or the like is used so that the moisture content after drying is a predetermined value. drying conditions, that is, predetermined temperature, humidity, drying time (in the case of cedar and cypress wood, for example, the drying temperature is about 40 to 100 ° C., the dry-wet bulb temperature difference is about 1 to 30 ° C., the drying period is about 3 to 10 days), etc. Normally, during the drying period, the drying temperature is set to gradually rise and the humidity is set to gradually fall.

Although it is possible to increase the strength by lowering the moisture content, if the moisture content of the wood NW is lowered more than necessary, the strength is impaired due to shrinkage of the wood NW, and cracks or the like occur during the drying process. In particular, when the wood NW has knots K, the knots K and their surroundings have high hygroscopic properties, and the moisture easily evaporates. , cracks and the like are likely to occur.
Therefore, for example, in the case of cedar wood, cypress wood, etc., it is preferable to dry the wood NW so that the moisture content of the entire wood falls within the range of 5% to 15%. More preferably, the water content is in the range of 8% to 10%.

Here, in the laminated plastically processed lumber LPW according to the present embodiment, a plurality of lumbers NW (NW _D1 , NW _D2 , NW _I1 , NW _I2 , NW _I3 , etc.) are laminated, and the laminated body LW is heated and compressed. The thickness of one piece of laminated plastic processed wood LPW is obtained by performing a consolidation process, and each piece (one piece) of wood NW (NW _D1 , NW _D2 , NW _I1 , NW I2 , NW I2 , NW _I2 , NW _I3 , etc.) can be made thinner. That is, for example, as a laminated plastic processed wood LPW that can be used for applications such as a desk for school children, a study desk, a work desk in an office, a desk such as a dining table at home, a shelf board, etc., three or more thin sheets Thick wood NWs are stacked and heat-compressed. For example, thin wood NWs with a thickness of 10 mm to 30 mm, preferably 12 to 25 mm, are dried.

Therefore, each wood NW used as a raw material for laminated plastic-worked wood LPW can be dried in a short drying time, and drying cracks on the surface are less likely to occur. can be approximated to That is, even if the laminated plastic-worked wood LPW is made to have a predetermined thickness, each wood NW used as the raw material can be made thin, so the load due to drying can be reduced. Therefore, even when a material having knots is used as the raw material wood NW, it is difficult to cause knot cracking and knot dropout due to drying, and the yield can be improved. In addition, since the variation in water content between the inside and the surface side of the wood NW can be reduced, it becomes difficult to cause local compressive deformation and stress in subsequent hot compression, and internal cracking of the wood due to hot compression is prevented. Even if there are knots, cracks, fissures and the like are less likely to occur there. In addition, since the drying time of the wood NW is short, the productivity is also good.

In addition, when carrying out the present invention, means for drying the wood NW to a predetermined moisture content is not limited to artificial drying, and natural drying may be used in combination. In the above description, lumber cut from raw wood or logs is sawed into a predetermined size and then dried. It may be lumbered to a predetermined size after it is dried.

Next, the wood NWs (NW _D1 , NW _D2 , NW _I1 , NW _I2 , NW _I3 , etc.) dried to a predetermined moisture content in this way are placed in the direction perpendicular to the length direction of each grain, that is, Laminated lumber LW is formed by interposing an adhesive in the thickness direction of lumber NW.
In the present embodiment, three or more wood pieces NW are laminated, and the number of laminated wood pieces NW is set according to the application, purpose, etc. of the laminated plastically worked wood LPW.

As shown in FIGS. 1 to 4, in the present embodiment, the wooden pieces NW (NW _D1 , NW _D2 , NW _I1 , NW _I2 , NW _I3 , etc.) are laminated with their grain lengths matched. there is
As long as the lengths of the wood grains are matched to each other and laminated, as will be described later, even if the wood NW has knots K, when the wood NW is heat-compressed, the wood structure of the opposing laminated wood structure will change. The knots are easy to press, and compressive stress is less likely to be applied to the knots K. Therefore, when there are many knots, for example, when knots exist at a high occupancy of 10% to 20% and the partial specific gravity difference is large, when there are knots penetrating the front and back surfaces of the wood NW, and when the wood NW has a diameter of 20 mm Even when the above knots are present, the knots are prevented from being crushed during heating and compression, and buckling deformation is prevented from occurring around the knots.

Further, in the present embodiment, the lumbers NW _D1 and NW _D2 are arranged so that the front and back surfaces of the laminated lumber LW formed by laminating the lumbers NW become the cross-grained surface or chamfered surface on the wood surface side. That is, the laminated lumber LW has a design surface on the cross grain surface or the chamfered surface on the wood surface side of each of the lumbers NW _D1 and NW _D2 arranged on the front and back layers, and each of the lumbers NW _D1 and NW _D2 on the opposite side. The cross-grain surface or chamfered surface of the back side is the surface facing the wood NW _I (NW _I1, NW _I2, NW _I3 , etc.) of the intermediate layer to be laminated.
As a result, the front and back layers, that is, NW _D1 and NW _D2 on the design surface side, are easily deformed by the pair of press plates 10A and 10B sandwiching the laminated wood LW during heat compression, and the compressive stress generated during heat compression can be reduced. Therefore, it is possible to prevent wood cracking due to buckling deformation of annual rings, and to reduce the internal stress, so even if a material with knots is used, cracks such as cracks are unlikely to occur in the knots during heat compression. Become. In addition, since the compression rate and the anisotropy of shrinkage are balanced between the front and back surfaces, local compression deformation and stress are less likely to occur, and distortion due to compression is small. Even if expansion/contraction force is generated due to change, the dimensional shape stability is high.

When the laminated plastic processed wood LPW of the present embodiment is applied, for example, to a top board or a shelf board used for desks such as school children's desks, study desks, office work desks, home dining tables, etc. To explain with an example, when a coniferous tree such as cedar or cypress is used as the wood NW before processing, which is the raw material of the laminated plastic processed wood LPW, three pieces with a thickness within the range of 6 mm to 15 mm are used. Lamination of timbers NW _D1 , NW _D2, NW _I1 , four timbers NW _D1 , NW _D2, NW _I1, NW _I2 , or five timbers NW _D1 , NW _D2, NW _I1, NW _I2 , NW _I3 material LW. At this time, the total thickness of the laminated lumber PW in which 3 to 5 lumbers NW _D1 , NW _D2, NW _I1, NW _I2 and NW _I3 are laminated is, for example, within the range of 20 mm to 75 mm, preferably 25 mm to 60 mm. Within range. However, when carrying out the present invention, the number and thickness of the wood pieces NW, which are the raw materials of the laminated plastic-worked wood piece LPW, are not limited to these. Although an adhesive is actually applied between the lumbers NW of the laminated lumber LW, the above thickness is a value ignoring the applied thickness of the adhesive. Here, hereinafter, when NW _D1 , NW _D2, NW _I1, NW _I2 , and NW _I3 are not particularly distinguished, they are simply referred to as “timber NW”, and the inner layer timber placed between the front and back layer timbers NW _D1 and NW _D2 NW _{I1 ,} NW _I2 , and NW _I3 are simply referred to as "timber NW _I " when not specifically distinguished.

FIG. 1 shows an example in which three pieces of wood NW are laminated. A laminated lumber LW made by laminating three lumbers NW _D1 , NW _{D2, and} NW _I1 is arranged such that the lengths of the grains of the lumbers NW _D1 , NW _{D2, and} NW _I1 match each other, and the length of the grain is It is an arrangement in which the cross grain surface or chamfered surface on the wood surface side of each of the wood pieces NW _D1 and NW _D2 located on the front and back layers is used as the design surface.

2 and 3 are examples in which four pieces of wood NW are laminated. Laminated lumber LW formed by laminating four lumbers NW _D1 , NW _D2 , NW _I1 , NW _I2 is obtained by matching the grain lengths of the lumbers NW _D1 , NW _D2, NW _I1, NW _I2 to each other, so that the wood grain It is laminated in the direction perpendicular to the length direction, and is arranged so that the cross grain surface or chamfered surface on the wood surface side of each of the timbers NW _D1 and NW _D2 located in the front and back layers is the design surface. At this time, the two timbers NW _{I1 and} NW _I2 of the inner layer placed between the timber NW _D1 and the timber NW _D2 of the front and back layers are arranged such that the opposing surfaces to be superimposed on each other are the cross grain surface on the front side of the wood or the cross grain surface as shown in FIG. It is preferable to use the chamfered surfaces side by side, or, as shown in FIG. As a result, the anisotropy of shrinkage is balanced, so that the strain due to compression is small, and the dimensional shape stability is high even if expansion and contraction forces are generated due to changes in ambient environmental conditions after compaction.

That is, the laminated lumber LW formed by laminating the _{four lumbers} NW _D1 , NW _{D2 ,} NW _I1 and NW _I2 shown in FIG. The inner layer timbers NW _{I1 and} NW _I2 face the cross-grained or chamfered sides of the back side of the wood NW _{I1 and NW I2, and the inner-layer lumbers NW I1 and} NW _I2 face each other on the cross-grained or chamfered sides of the wood front side. It is. In this way, in the case where the cross-grained surface or the straightened surface side of the back side of the wood NW _D1 and NW _D2 of the front and back layers faces the cross-grained surface or the straightened surface side of the back side of the wood NW _{I1 and} NW _I2 of the inner layer, Since the lumbers NW _D1 and NW _D2 of the front and back layers are easily deformed by the pair of press plates 10A and 10B sandwiching the laminated lumber LW during heat compression, that is, the compressive force is easily concentrated, the surface hardness can be further increased. It is possible. Furthermore, since the internal stress due to the heat compression force can be reduced, even if there are many knots, even if there are knots that penetrate the front and back of the wood, or if there are knots with a diameter of 20 mm or more, the knots can be reduced during heat compression. Fractures such as cracks and fissures are less likely to occur in the portion K. In addition, when the number of the inner layer timbers NW to be arranged between the timbers NW _D1 and the timbers NW _D2 of the front and back layers is an even number of 2 or more, the front side and the back side of the wood are alternately reversed and stacked. Distortion can also be prevented by balancing the anisotropy of compression.

On the other hand, the laminated lumber LW formed by laminating the _{four lumbers} NW _D1 , NW _D2, NW _I1 and NW _I2 shown in FIG. The face side of the inner layer wood NW _I1, NW _I2 faces the cross-grain surface or chamfered surface on the front side of the wood, and the inner layer lumber NW _I1, NW _I2 faces each other on the cross-grained surface or chamfered surface of the wood back side. It is what I did. In this way, in the case where the cross grain surface or the straightened surface side of the back side of the wood NW _D1 and NW _D2 of the front and back layers faces the cross grain surface or the straightened surface side of the wood surface side of the inner layer wood NW _{I1 and} NW _I2 , The front and back of the laminated wood LW are in a symmetrical relationship, and the wood NW interacts with each other to prevent warping deformation, distortion, etc. in a specific direction. Therefore, the dimensional shape stability becomes higher.

In any case, when an even number of inner-layer timbers NW _I are laminated between the timber NW _D1 and the timber NW _D2 of the front and back layers, the cross-grained surfaces on the front side of the wood or the cross-grained surfaces on the back side of the wood and the cross-grained on the back side of the wood are used. The anisotropy of shrinkage is balanced by laminating and adhering the surfaces or the chamfered surfaces to face each other, and warp deformation, distortion, etc. in a specific direction can be prevented, thereby improving the dimensional and shape stability.

Moreover, FIG. 4 is an example in which five pieces of wood NW are laminated. Even in a laminated lumber LW formed by laminating five lumbers NW _D1 , NW _D2, NW _I1, NW _I2 and NW _I3 , each lumber NW _D1 , NW _D2, NW _I1, NW _I2 and NW _I3 have grain lengths different from each other. are aligned and laminated in the direction perpendicular to the length direction of the wood grain, and the cross grain surface or the chamfered surface on the wood surface side of each of the wood NW _D1 and NW _D2 located in the front and back layers is the design surface. It is an arrangement that At this time, two pieces of wood NW _I among the three pieces of wood NW _{I1 ,} NW _I2 , and NW _I3 of the inner layer laminated between the pieces of wood NW _D1 and NW _D2 of the front and back layers have the facing surfaces to be overlapped with each other on the front side of the wood. It is preferable to use cross-grain surfaces or chamfered surfaces, or cross-grain surfaces or chamfered surfaces on the back side of the tree. As a result, the anisotropy of shrinkage is balanced, so that the strain due to compression is small, and the dimensional shape stability is high even if expansion and contraction forces are generated due to changes in ambient environmental conditions after compaction.

That is, even if the number of the inner layer timbers NW _I laminated between the timber NW _D1 and the timber NW _D2 of the front and back layers is three or more, even if the number of timbers NW I is an odd number, the front side and the back side of the wood may face each other in part. However, it is possible to prevent distortion due to compression by laminating and bonding the cross-grained surfaces or straightened surfaces on the front side of the wood or the cross-grained surfaces or straightened surfaces on the back side of the wood facing each other. Become. In addition, even if expansion and contraction forces occur due to changes in the surrounding environmental conditions after consolidation, the timbers that are stacked on top of each other interact with each other to prevent warping and deformation in a specific direction. can be secured.

Here, when using a material with knots for the wood NW as the raw material of the laminated plastic-worked wood LPW, it is preferable to overlap a part of another wood NW with no knots on a part of the wood NW with the knot K. That is, the portion (1 cm ³ unit) of the mating material that is opposed to the location where the knot K of the wood NW is located has a lower specific gravity and a lower fiber density than the location where the knot K is located. In a portion without knots in the wood structure, that is, in a portion with low specific gravity and low density of fibers without knots K, when heated and compressed, it is pressed by the knots K of the wood NW and can be softened and deformed. Depending on the compressibility, a cushioning effect suitable for the compression is obtained, and even if the wood is heated and compressed, the knots follow the environment, so that the knots K of the wood NW are less likely to be subjected to compressive stress. In other words, even if a material with knots is used, by stacking the wood NWs together, the specific gravity is different in the direction perpendicular to the length direction of the wood grain, that is, in the thickness direction of the wood NW. Buckling deformation of the fibers around the knots of the wood NW is suppressed, and excessive stress is less likely to be applied to the knots and their surroundings. Furthermore, in the present embodiment, even if the wood NW _D1 and the wood NW _D2 of the front and back layers are highly compressed, the wood NW _I of the inner layer is low-compressed. An unreasonable compressive load is hard to be applied to the portion K, and the hard knot portion K is hard to be distorted and stressed. In addition, since the compression is balanced between the front and back sides, it is difficult to cause local compression deformation and stress. Therefore, it is possible to obtain a laminated plastic processed wood LPW having a mechanical strength higher than that of the original wood by consolidation without causing crushing, breakage, fissures, cracks, etc. of the knots K.

Then, in the present embodiment, an adhesive is applied to the facing surfaces of the wood pieces NW to be laminated before heat compression.
As the adhesive for bonding the pieces of wood together, any adhesive that can bond the pieces of wood together under the conditions of the subsequent pair of press plates 10A and 10B, that is, the heat compression process using a hot press can be used. good. For example, adhesives for bonding wood together include water-based vinyl urethane-based adhesives (water-based polymer isocyanate-based adhesives), urethane resin-based adhesives, vinyl acetate resin-based adhesives, urea resin-based adhesives, and epoxy resins. A resin-based adhesive, a phenolic resin-based adhesive, a synthetic rubber-based adhesive, or the like can be used. In particular, in this embodiment, a thermosetting adhesive that adheres wood together by being cured during heat compression, which will be described later, or a two-liquid mixing reaction curing type adhesive is used. The amount of adhesive to be applied at this time is determined by the type of adhesive, etc. For example, in the case of a water-based vinyl urethane adhesive, the amount to be applied is preferably 200 g/m ² or more. If the water-based vinyl urethane adhesive is used, the adhesive can easily permeate even wood made of coniferous trees, and a sufficient adhesive strength can be obtained to firmly bond the wood together in the subsequent heating and compression process. In particular, in the case of a material with knots, it also permeates the knots K, making it possible to relax the compressive stress applied to the knots K in the subsequent heating and compression process, and to protect the knots. It is effective in preventing cracking of the joint K during the compression process.
Note that the method of applying the adhesive is not particularly limited, and the adhesive may be applied to one side of the wood NW. If applied, it is possible to apply the adhesive for bonding with less labor and man-hours.

At this time, the laminated lumber LW, which is formed by laminating three or more lumbers NW with an adhesive interposed therebetween, is lumber obtained by adding moisture to the lumbers NW _D1 and NW _D2 of the front and back layers after drying. may be used. That is, when carrying out the present invention, after drying to a predetermined moisture content as described above, when wood is laminated, NW _D1 and NW _D2 on the upper and lower layers are heat-compressed. In order to facilitate the stacking, moisture may be added to the woods NW _D1 and NW _D2 arranged on the upper layer side and the lower layer side when laminated, that is, humidification may be performed. For example, by immersing the entire dried wood pieces NW _D1 and NW _D2 in water for a predetermined time (for example, the immersion time is about 5 minutes), water can be added to obtain a predetermined moisture content. The means for adding moisture to the surface side of the dried wood NW _D1 and NW _D2 is not limited to immersing the wood NW _D1 and NW _D2 in water, and spraying or spraying water on a specific surface with a spray or the like is also possible. Alternatively, water may be applied with a brush or the like.

Next, the laminated lumber LW, which is obtained by laminating three or more lumbers NW with an adhesive interposed therebetween, is heat-compressed to perform consolidation by heat-compression and compression fixation, and curing of the adhesive. The wood is joined together by

Here, as shown in FIGS. 5 and 6, the plastic-worked lumber manufacturing apparatus 100 for consolidating the laminated lumber LW in which a plurality of lumbers NW are laminated mainly includes an upper press platen 10A and a lower press platen 10B. A press platen 10 forming an internal space IS by a structure divided into two, and a peripheral edge portion 10a of the upper press platen 10A facing the peripheral edge portion 10b of the lower press platen 10B. and a pipe port 12a that communicates with the interior space IS from the upper surface side of the upper press platen 10A and supplies steam into the interior space IS. a valve V4 on the upstream side thereof; a pipe 13 communicating with the inner space IS from the side surface of the lower press platen 10B and having a pipe port 13a for discharging water vapor from the inner space IS; 13, a valve V5 on the downstream side thereof, a drain pipe 14 connected to the valve V5, and the like.

In the upper press platen 10A and the lower press platen 10B of the press platen 10, piping lines 15 and 16 are formed for raising the temperature to a desired temperature by passing high-temperature steam through them. , 16 are connected to pipes ST2 and ST3 branched from the pipe ST1 on the steam supply side, and pipes ET1 and ET2 on the steam discharge side, respectively. Valves V1, V2 and V3 and a pressure gauge P1 for detecting the steam pressure in the pipe ST1 are arranged in the middle of the pipes ST1, ST2 and ST3 on the steam supply side, and pipes ET1 and ET2 on the steam discharge side. is connected to a drain pipe 14 via a valve V6.

Furthermore, the press platen 10 has a cooling water supply side for cooling to a desired temperature by passing low-temperature cooling water instead of water vapor through pipes 15 and 16 formed in the upper press platen 10A and the lower press platen 10B. Pipes ST12 and ST13 branched from the pipe ST11 are connected to the pipes ST2 and ST3, respectively. Further, valves V11, V12 and V13 are arranged in the middle of the pipes ST11, ST12 and ST13 on the cooling water supply side.

A boiler device that supplies water vapor to the pipe ST1, a cooling water supply device that supplies cooling water to the pipe ST11, and the upper press platen 10A are raised/lowered with respect to the lower press platen 10B on the stationary side of the press platen 10 to apply pressure. A press lifting device including a hydraulic mechanism for pressing is omitted.
In the present embodiment, high-temperature steam is introduced to heat the upper press platen 10A and the lower press platen 10B of the press platen 10. However, when the present invention is carried out, the heating medium for the press platen 10 is high-temperature steam. There is no limitation, and oil or the like may be used, or wood may be heated by a heating means such as high-frequency heating, microwave heating, or a heater. In particular, for high-frequency heating of lumber, a method of heating lumber from its center with a high frequency slightly lower than that of microwaves is more suitable than dielectric heating by microwaves.

In the press platen 10 made of iron or the like, a flat mold having a flat size capable of pressing the entire front and back surfaces in the direction perpendicular to the stacking direction of the laminated wood LW is used. In order to prevent the blackening due to iron ion contamination, for example, steel materials such as stainless steel and aluminum are used for the mold, and the front and back contact surfaces of the laminated wood LW are plated. Further, the material of the seal member 11 for sealing the internal space IS is not particularly limited, but silicone rubber, silicone resin, etc., which are excellent in heat resistance and water resistance, are usually used.

In order to consolidate the laminated lumber LW using the plastically worked lumber manufacturing apparatus 100 configured as described above, first, as shown in FIG. On the other hand, the upper press platen 10B on the movable side is raised, and the laminated lumber LW is placed on the lower press platen 10B on the fixed side.

Here, in the present embodiment, the direction of press compression by the press platen 10 divided into the upper press platen 10A and the lower press platen 10B is the direction perpendicular to the grain length direction of the laminated wood LW. A compressive force is applied in a direction perpendicular to the surfaces (front and back surfaces perpendicular to the thickness direction of the laminated wood LW).

At this time, in the present embodiment, since the front and back surfaces of the laminated wood LW are the cross-grained surface or the chamfered surface on the front side of the wood, one of the front and back layers (outer layers) of the laminated wood LW (lower layer in the figure) The wood face side of the cross-grain surface or chamfered face of NW _D2 is opposed to the lower press platen 10B, and the other (upper layer in the figure) wood NW _D1 is placed on the wood face side of the cross-grain surface or chamfered face of the upper press platen 10A. , and the cross grain surface or chamfered surface on the wood surface side of the surface perpendicular to the length direction of the wood grain of the laminated lumber LW is the surface to be press-compressed by the press platen 10 .

In carrying out the heating and compression treatment, the surface side of the laminated wood LW perpendicular to the grain direction is opposed to the upper press platen 10A and the lower press platen 10B of the press platen 10, and the lower press platen on the fixed side is pressed. As shown in FIG. 6(b), first, the upper press platen 10A is lowered under a predetermined pressure (for example, 0.05 to 0.3 [MPa]) to laminate the laminated lumber LW placed on 10B. The upper surface of the timber LW, that is, the cross-grained surface or chamfered surface of the timber NW _D1 perpendicular to the grain length direction is brought into contact for a predetermined time (for example, 10 to 120 seconds). At this time, water vapor at a predetermined temperature (for example, 110 to 210 [° C.] and a temperature rising treatment time of 10 to 25 [minutes]) is passed through the upper press platen 10A and the lower press platen 10B. 10A and lower press platen 10B are heated to a predetermined temperature (for example, 110 to 210 [° C.]).

Then, the compression pressure of the upper press platen 10A is set to a predetermined pressure (for example, 2 to 5 [MPa], 20 to 50 kg/cm ² ) relative to the lower press platen 10B on the fixed side, and the upper press platen 10A is lowered. The laminated lumber LW is heated and compressed by the upper press platen 10A and the lower press platen 10B, for example, at a processing time of 0.5 to 3 [minutes] and a compression speed of 15 to 100 [mm/minute]. When the upper press platen 10A descends, the laminated lumber LW is heated and compressed by the upper press platen 10A and the lower press platen 10B, and the peripheral edge portion 10a of the upper press platen 10A contacts the peripheral edge portion 10b of the lower press platen 10B. As shown in FIG. 6(c), the internal space IS formed by the upper press platen 10A and the lower press platen 10B is sealed by the seal member 11 disposed on the peripheral edge portion 10a of the upper press platen 10A. .

In the present embodiment, the vertical dimension of the internal space IS formed by the upper press platen 10A and the lower press platen 10B of the press platen 10 when the internal space IS is in a sealed state via the seal member 11. The interval is set to the finished dimension in the thickness direction when the press platen 10 forms the plastically processed lumber PW having a predetermined compressibility with respect to the thickness of the laminated lumber LW. Therefore, the compressibility of the entire thickness of the laminated wood LW, that is, the change in the plate thickness (compression amount) due to the compression of the laminated wood LW, is such that the peripheral edge 10a of the upper press platen 10A hits the peripheral edge 10b of the lower press platen 10B. It will be determined by contact. The pressure, heating temperature, heating time, compression speed, etc., of the press platen 10 at this time are set to optimum values in advance through experiments or the like using factors such as the tree species of the wood and the moisture content of the dried wood as parameters.

With respect to the press platen 10 heated to a predetermined temperature in this way, when the lower press platen 10B is fixed and the upper press platen 10A is moved to contact the upper surface of the laminated wood LW with a predetermined pressure and is lowered at a predetermined compression speed, the laminated wood is lowered. Changes in the chemical properties of wood components from the front and back layers of LW cause a decrease in strength (hydrolysis of amorphous components such as hemicellulose and lignin, and a decrease in softening point), and the cells are compressed and deformed, reducing the voids in the cells. To go.

In particular, in the present embodiment, a laminated wood LW formed by laminating three or more _{woods NW} is sandwiched between a pair of press plates 10 and heat-compressed. However, since the sawn wood NWs are arbitrarily combined and laminated, the wood structure of the front and back layers of the wood NW _D1 , NW _D2 and the inner layer of the wood NW _I is not continuous, Since the wood structure changes between the wood NW _{D1 , NW D2 of the front and back layers and the wood NW I of the inner layer, the wood NW D1 , NW D2 of the front} and back layers is heated and compressed from the front side to the back side of the wood. The angle of the annual ring line RL is usually sharp from the front side to the back side of the wood NW _D1 and NW _D2 of the front and back layers, and the specific gravity, hardness, and fiber strength are high, so that compression deformation is difficult. is. In particular, when the tree ring angle of the inner layer wood NW _I is smaller than that of the front and back layer woods NW _D1 , NW _D2 , it is possible to increase the difference in compression rate between the design materials PW _D1 , PW _D2 described later and the inner layer material PW _I1 . It is possible to increase the surface hardness by increasing the compressibility of the design materials PW ₁ and PW ₂ without cracking even if there are knots.
Therefore, due to the difference in mechanical properties when heated and compressed, the timbers NW _D1 and NW _D2 arranged in the front and back layers of the laminated wood LW are highly compressed, and the inner layers arranged between the timbers NW _D1 and NW _D2 in the front and back layers are compressed. The wood NW _I can have a lower compression than the woods NW _D1 and NW _D2 of the front and back layers.

In this way, in the present embodiment, a plurality of lumbers NW are laminated to form a laminated lumber LW, which is sandwiched between a pair of press plates 10A and 10B and thermally compressed. Even if the portion K exists, the wood component of the low specific gravity portion without knots of the wood NW on the opposite side that is superimposed on it softens during the heat compression and is deformed by the pressing by the hard knot K, so that the hard knot. Do not apply compressive stress to K. Furthermore, although the timbers NW _D1 and NW _D2 in the front and back layers of the laminated timber LW are highly compressed, the inner layer timber NW _I arranged between the timbers NW _D1 and NW _D2 in the front and back layers is compressed more than the timbers NW _D1 and NW _D2 in the front and back layers. Since the compression is also low, even if the joint K exists, an excessive compressive force is not applied to the joint K. Therefore, even if the laminated wood NW has a knot portion K, the knot portion K is less likely to be broken or crushed, or the fibers around the knot portion to undergo buckling deformation during heat compression.

If the peripheral edge portion 10a of the upper press platen 10A and the peripheral edge portion 10b of the lower press platen 10B are configured with, for example, a jig, a formwork, a gauge, etc. for controlling the thickness, the plastically processed wood PW can be obtained as desired. The height of the peripheral edge portion 10a of the upper press platen 10A and the peripheral edge portion 10b of the lower press platen 10B can be adjusted according to the finished thickness. Furthermore, at this time, it is also possible to arrange a restrictor (spacer) (not shown) for restricting lateral (horizontal) extension, for example, on the side surface of the laminated lumber LW. If the change in extension of the laminated lumber LW in the lateral direction (horizontal direction), that is, the change in extension in the direction perpendicular to the direction of compression is restricted by the restrictor, it becomes easier to fix the specific dimensions and specific gravity, thereby making it easier to fix the product. Variation can be prevented and high quality can be ensured. When such restrictions are applied, the density may increase at the ends of the wood in the width direction. Conversely, if there is no regulation, the width-direction end portions of the lumber may have a lower density than the central portion. Depending on the density difference in the width direction of the wood, it is also possible to cut the surface of the wood on the side of the width direction end after the consolidation process. Furthermore, when commercializing, a plurality of laminated lumber LWs are arranged in the grain length direction of the laminated lumber LW and in the width direction orthogonal to the grain length direction, and are integrally consolidated and joined. is also possible.

Next, the compression pressure of the upper press platen 10A and the lower press platen 10B is maintained in the closed state of the internal space IS shown in FIG. , 110 to 210[° C.]), fixing of the heat-compression treatment of the wood, so-called fixing treatment of the wood is performed.
For example, a predetermined steam pressure is supplied to the sealed internal space IS via a pipe 12 and a pipe port 12a (FIG. 5) connected to the valve V4 to compress the upper press platen 10A and the lower press platen 10B. While maintaining the pressure and heating temperature at the same predetermined pressure and temperature as the pressure and heating temperature at the time of heat compression, the internal space IS in a sealed state is at a predetermined temperature and vapor pressure for a predetermined time (for example, 20 minutes to 90 minutes). retained. By introducing high-temperature steam at a predetermined temperature (for example, 110 to 210 [° C.]) into the internal space IS and setting the internal space IS in a sealed state to a predetermined temperature and steam pressure, the sealed state is achieved by the action of the high-temperature and high-pressure steam. A sufficient chemical change is caused to the heat-compressed lumber arranged in the internal space IS of the lumber to make the properties uniform. As a result, it is possible to form a laminated plastic-worked lumber LPW that does not return when the subsequent cooling compression is released.

At this time, high-temperature and high-pressure steam pressure can freely flow between the peripheral surface of the heat-compressed lumber and the inside thereof. The inside of the sealed internal space IS may be adjusted to a predetermined vapor pressure. For example, excess moisture in the interior space IS is removed based on the moisture content of the front and back surfaces of the wood, and the interior space IS is adjusted to a predetermined vapor pressure. At this time, when the heat-compressed lumber is fixed in the sealed state of the internal space IS, the vapor pressure of the internal space IS is detected by the pressure gauge P2 as the vapor pressure control process, and the valve V5 is appropriately adjusted. , is opened and closed. As a result, high-temperature and high-pressure steam can be discharged from the internal space IS to the drain pipe 14 side through the pipe port 13 a and the pipe 13 . Also, if necessary, a predetermined steam pressure can be appropriately supplied to the internal space IS that is in a sealed state.

Then, as shown in FIG. 6(d), immediately before the shift from heating compression to cooling compression by the upper press platen 10A and the lower press platen 10B, the valve V5 is opened as steam pressure control processing, thereby High-temperature and high-pressure steam is discharged from the compression space IS to the drain pipe 14 side through the port 13 a and the pipe 13 . As a result, heat compression treatment of wood, so-called fixation of wood, is further promoted. At this time, the supply of water vapor for maintaining the upper press platen 10A and the lower press platen 10B at the specific temperatures is temporarily stopped.

Finally, as shown in FIG. 6(e), normal-temperature cooling water is passed through the piping 15 of the upper press platen 10A and the piping 16 of the lower press platen 10B, thereby cooling the upper press platen 10A and the lower press platen 10B. It is cooled to about room temperature and held for a predetermined time (for example, 20 to 90 [minutes]). At this time, the compression pressure of the upper press platen 10A against the lower press platen 10B on the fixed side is kept at the same predetermined pressure (for example, 2 to 5 [MPa]) as the pressure at the time of heat compression. 10A and lower press platen 10B are cooled.
Thereafter, as shown in FIG. 6(f), the upper press platen 10A is raised with respect to the lower press platen 10B on the fixed side, and the laminated plastic processed wood LPW _P that has undergone the consolidation processing by heat compression and compression fixing is placed inside. A series of processing steps is completed by removing from the space IS. In the laminated plastically worked wood LPW _P taken out from the internal space IS, the adhesive applied between the woods NW is cured by heating and cooling in a series of processing steps, and the woods are integrally laminated and joined.

Thereafter, usually, in order to ensure the flatness of the product, only one surface or both surfaces of the laminated plastic processed lumber LPW _P are cut. Moreover, you may cut a side surface. After cutting the laminated plastically worked wood LPW _P , it becomes laminated plastically worked wood LPW as a finished product. If necessary, the surface of the laminated plastically worked wood LPW may be surface-coated with a resin or the like as a countermeasure against moisture and dirt.

In the present embodiment, the laminated plastic processed lumber LPW manufactured by such a manufacturing method is obtained by sandwiching and pressing the laminated lumber LW formed by laminating the lumber NW between a pair of press plates 10A and 10B. The timbers NW _D1 and NW _D2 located in the front and back layers of the laminated timber LW are highly compressed, and the inner layer timber NW _I located between the timbers NW _D1 and NW _D2 in the front and back layers is compressed more than the timbers NW _D1 and NW _D2 in the front and back layers. It is a plastic working with low compression.

Further, the laminated plastic-worked lumber LPW according to the present embodiment is produced by laminating a plurality of lumbers NW in a specific direction and interposing an adhesive between the lumbers NW to produce the laminated lumber LW. By heat-compressing using 100, the lumbers are integrally laminated and joined with an adhesive.

In particular, in the present embodiment, since the adhesive is applied between the wood pieces NW of the laminated wood pieces LW before heat compression, the adhesive is cured during the heat compression for consolidation of the laminated wood pieces LW, and the wood pieces NW are integrated. join to That is, by heating and compressing the laminated lumber LW, the lumbers are joined while being compacted. As a result, compared to the case where the timber NWs are separately joined together via an adhesive by pressure using a press plate or the like and then subjected to the consolidation process, or the timbers laminated and subjected to the consolidation process are separately processed after the consolidation process. Compared to the case where the parts are integrally joined by pressing with a press platen or the like via an adhesive, the number of manufacturing steps is reduced and the manufacturing time is also shortened.

That is, the laminated plastic-worked lumber LPW according to the present embodiment is composed of two thin design materials PW _{D1 and} PW obtained by highly compressing the lumber NW _D1 and NW _D2 arranged in the front and back layers of the laminated lumber LW by thermal compression. _D2 and one or more pieces of wood NW _I arranged between the woods NW _D1 and NW _D2 of the front and back layers of the laminated wood LW are compressed by heating to a lower compression than the design materials PW _{D1 and} PW _D2 of the front and back layers. It is formed from one or more thick inner layer materials PW _I (PW _I1 , PW _I2 , PW _I3 , etc.), and the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I are laminated and joined together to be integrated. It is. Hereinafter, the inner layer materials PW _{I1 ,} PW _I2 , and PW _I3 disposed between the design materials PW _{D1 and} PW _D2 of the front and back layers will simply be referred to as "inner layer materials PW _I " when they are not particularly distinguished.

Here, the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I can be distinguished from each other by changes in the joint line L and the annual ring line RL, which are densely formed at their boundaries. , In the design materials PW _{D1 and} PW _D2 arranged in the front and back layers of the laminated plastic processed wood LPW, the amount of compressive deformation of the cells is large due to high compression, and the annual ring line RL is narrow, dense, and thin. In the inner layer material PW _I disposed between the design materials PW _{D1 and} PW _D2 , the compression is lower than the design materials PW D1 and PW _D2 , the amount of compressive deformation of the cells is small, the annual ring line RL is wide, the density is low, and the thickness is high. . Therefore, the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I have a large difference in the amount of compressive deformation of cells due to heat compression.

Specifically, in the laminated plastic-worked wood LPW according to the present embodiment, the design materials PW _{D1 and} PW _D2 are compressed by heating to 45% to 65% with respect to the air-dried specific gravity of the original wood NW, preferably Compressed at a compression rate within the range of 50% to 60%, the inner layer material PW _I is compressed by heating to a compression rate of 10% to 40%, preferably 20% to 40%, relative to the air dry specific gravity of the original wood NW. It is compressed with a compression rate within the range of . As a result, the specific gravity of the surface can be made higher than that of the entire body, and lightness, surface hardness, and strength can be achieved at the same time.
The compressibility is obtained from the air-dried specific gravity of the original wood NW and the air-dried specific gravity measured by cutting out the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I of the laminated plastic processed wood LPW at the joint surface. is calculated, and considering the difference in specific gravity due to the presence of knots, it may not necessarily fall within the above range in the measurement of a specific part cut out. In addition, even if there is an error due to measurement, etc., since it deals with natural objects, it is not impossible to implement it, and it does not deny the intervention of the error.

In the present embodiment, the difference in compression rate between the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I is, as described above, due to the combination and lamination of the timber NWs that have been sawn in a predetermined manner, and the timber structure between the timbers NW. Using the fact that resistance is generated there, the wood NW _D1 and NW _D2 of the front and back layers are greatly compressively deformed, while the wood NW _I inside between the wood NW _D1 and NW _D2 of the front and back layers is compressively deformed. It is a reduced amount. Then, in the case of consolidating the combination and lamination of the lumbers NW that have been sawn in a predetermined manner, depending on the combination of the lumbers NW _D1 and NW _D2 of the front and back layers and the lumber NW _I inside, for example, the lumber to be laminated It is possible to easily control the characteristics such as the surface hardness of the consolidated plastically worked wood LPW by combining the size of the annual ring angle of the NW, the combination of the material with knots and the material without knots, and the like.

In the laminated plastic-worked wood LPW according to the present embodiment, which is composed of the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I , the design materials PW D1 and PW _D2 and the inner layer material PW _I differ from each other in compression amount and consolidation density. As a whole, the mechanical strength is higher than that of the original wood NW and the laminated wood LW due to the consolidation process and bonding between the woods with an adhesive. In particular, the design materials PW _{D1 and} PW _D2 are compressed to a higher degree than the inner layer material PW _I by the consolidation process, and the voids in the cell lumens are reduced, resulting in a hard and strong woody quality.

In this way, two thin design materials PW _{D1 and} PW _D2 obtained by highly compressing the timbers NW _D1 and NW _D2 arranged on the front and back layers of the laminated timber LW by heat compression, and the timber NW _D1 of the laminated timber LW. , and NW _D2 , and an inner layer material PW _I that is made by heating and compressing the internal wood NW _I arranged between the design materials PW _{D1 and} PW _D2 and having a thickness lower than that of the design materials PW D1 and PW D2. In the laminated plastic processed wood LPW of the form, by highly compressing only the design materials PW _{D1 and} PW _D2 of the front and back layers, high surface hardness can be achieved even if lightness is secured by low compression rate and low specific gravity as a whole. Obtainable.
Therefore, for example, in a laminated plastic processed wood LPW consisting of design materials PW _{D1 and} PW _D2 with a predetermined compression rate and density distribution and an inner layer material PW _I by using wood with a low specific gravity such as cedar and cypress. It is possible to make the material lighter than hard and high specific gravity broad-leaved trees such as oak and zelkova, even if the surface hardness is the same or higher. That is, it is possible to achieve both lightness and surface hardness.

In the example of consolidating coniferous trees such as cedar or cypress, the air-dried specific gravity of laminated plastic processed wood LPW is in the range of 1.2 times or more and 1.7 times or less than the air-dried specific gravity of wood NW before processing. It is preferably within the range of 1.3 times or more and 1.6 times or less. As a result, the design materials PW _{D1 and} PW _D2 that are highly compressed can provide high surface hardness and strength to eliminate the susceptibility of the original wood to scratches, while ensuring lightness.
In particular, the design materials PW _{D1 and} PW _D2 are highly compressed at a compression ratio of 45% to 65%, preferably 50% to 60%, relative to the air-dry specific gravity of the original wood NW by heat compression. As a result, the properties of the wood changed and the surface hardness increased significantly.

If surface hardness, strength, and lightness can be achieved at the same time, for example, it will be suitable for use as a top board for school desks, etc., which require easy carrying, writing, and resistance to scratches by cutters, etc. Furthermore, if it is lightweight for use as a top board or shelf board of a desk, etc., it is possible to increase the degree of freedom in designing support members such as legs that support it even when used as a top board or shelf board. becomes.

In addition, in the laminated plastic processed lumber LPW according to the present embodiment, which is composed of these highly compressed, thin design materials PW _{D1 and} PW _D2 and the low-compressed, thick inner layer material PW _I between them, the overall thickness of the laminated lumber LW is reduced. Since it is possible to suppress the increase in weight due to the reduction in volume and the increase in the overall specific gravity, high surface hardness can be secured by the highly compressed design materials PW _{D1 and} PW _D2 . can be provided at low cost.

Furthermore, in the laminated plastically worked wood _LPW of the present embodiment, the design materials PW _{D1 and PW D2} of the front and back layers are dense and hard, but the design materials _{PW D1,} PW Since it has a lower density than _D2 , it has a cushioning function due to the softness of the original wood NW, even when objects such as small objects collide with it, or when it collides with objects such as walls and floors. However, the impact can be absorbed and mitigated. Therefore, even if an impact is applied to the laminated plastic processed wood LPW, the impact noise is small, the design materials PW _{D1 and} PW _D2 are less likely to be damaged, and the colliding object is prevented from being damaged or damaged. Furthermore, for example, when it is used for the top plate of a study desk, etc., it can be expected to have an effect of absorbing writing sounds and the like, and an effect of soundproofing. In addition, even if the design materials PW _{D1 and} PW _D2 of the front and back layers are highly compressed and highly dense, the inner layer material PW _I inside them is low compression and low density. In addition, the design materials PW _{D1 and} PW _D2 , which are denser than the inner layer material PW _I , can increase the holding force of the joining members. Furthermore, since the internal inner layer material PW _I has a low density, it is easy to cut the butt end surface and the end surface side, and cutting and assembly are easy.

Then, the laminated plastically worked wood LPW of the present embodiment is obtained by stacking wood NWs, compressing them, and laminating and bonding them together. With respect to LW, the thickness of the wood NW _D1 and NW _D2 arranged on the front and back layers is highly compressed, and the internal wood NW _I arranged between the front and back NW _D1 and NW _D2 is made more than the wood NW _D1 and NW _D2 of the front and back layers. The compression rate is set to be low, and instead of uniformly compressing the entire thickness of each wood NW, the compression rate is different between the wood NW _D1 and NW _D2 arranged in the front and back layers and the wood NW _I in the inner layer between them. . Preferably, the compressibility of the decorative materials PW _{D1 and} PW _D2 is in the range of 1.5 to 5 times, more preferably in the range of 2 to 4 times the compressibility of the inner layer material PW _I . In terms of air-dry specific gravity, the air-dried specific gravity of the design materials PW _{D1 and} PW _D2 is preferably 1.3 times or more and 1.8 times or less, more preferably 1.8 times the air-dried specific gravity of the inner layer material PW _I. .4 times or more and 1.6 times or less.

Therefore, according to the laminated plastically worked wood LPW of the present embodiment, the design materials PW _{D1 and} PW _D2 formed by highly compressing the thickness of the wood NW _D1 and NW _D2 arranged on the front and back layers of the laminated wood LW provide high surface hardness. , while ensuring the strength, the inner layer material PW _I in which the thickness of the intermediate layer of wood NW _I arranged between the wood NW _D1 and NW _D2 of the front and back layers of the laminated wood LW is lower in compression than the design materials PW _{D1 and} PW _D2 . As a result, a strong compressive force is not applied to the entire thickness of the laminated lumber LW during heat compression.
In addition, the internal inner layer material PW _I is low-compressed by planar press compression from the top and bottom direction, while the design materials PW _{D1 and} PW _D2 sandwiching the inner layer material PW _I are highly compressed, so that the front and back are well balanced. , stress concentration and stress in a specific direction are difficult to enter during heating and compression.

In addition, since the wood structure can be softened and deformed by heat compression in the consolidation process, when wood NWs are stacked and heat-compressed, even if there are knots K, the hard knots K become the opposing member, that is, another member. A soft portion of the piled wood NW which has no knots and is easily softened and deformed and has a low specific gravity is pressed and bites into the portion. Therefore, the movement of the joint K is not constrained or regulated when it is heated and compressed. That is, even if the wood NW has knots K, the wood structure of the corresponding mating material stacked thereon is softened and deformed, so that when a compressive force is applied in a direction perpendicular to the length direction of the wood grain. Moreover, the movement of the joint K is not restrained or regulated. Therefore, the joint K is less likely to be stressed by the thermal compressive force, and a strong compressive load is not applied to the joint K.

In other words, the knot K has a high specific gravity and is hard, and is resistant to compression due to the difference in the fiber direction between the annual ring line RL and the knot K. Since the NWs are stacked and compacted, when a compressive force is applied in a direction perpendicular to the length of the wood grain, the knots K, which are resistant to compression, are transferred to another piece of wood that has knots K. By pressing the softened part of the wood due to heat compression, the mating material softens and deforms due to the pressing, so that the compressive force in the direction perpendicular to the length direction of the wood grain is buffered, so the knot K is forced to compress. Power and stress are hard to apply.

Thus, in the laminated plastically worked wood LPW of the present embodiment, even if there is a knot K, the design materials PW _{D1 and} PW _D2 of the front and back layers are highly compressed, and the internal inner layer material PW _I is lowly compressed. In addition to not applying strong compressive force and compressive stress to the inside of the laminated wood, the wood structure of the mating material stacked at the joint K is softened and deformed, so that the joint K is subjected to a strong compressive load, Compressive stress is not applied and little compressive stress is generated in the joint K. Therefore, even if a material with knots is used, for example, even if the knots K run perpendicularly or obliquely to the length direction of the grain of the wood NW, the knots K are crushed during heat compression, Fractures such as cracks and fissures are less likely to occur.

In particular, the design materials PW _{D1 and} PW _D2 of the front and back layers are highly compressed in this way, and the inner layer material PW _I of the inner layer is made low compression, so that it is difficult to apply compressive stress to the inside. However, in the consolidation process, even if a wood NW has a knot K, it is difficult for a strong compressive load to be applied to the knot K due to the softening and deformation of the wood structure of the corresponding mating material that is superimposed on the wood NW. Even if the compressibility of certain design materials PW _{D1 and} PW _D2 is increased, the knots K are less likely to crack. Therefore, it is possible to increase the surface hardness and strength without causing cracks, fissures, and the like at the knots K.

In addition, the structure of the knot K tends to decrease in size from the front side of the wood to the back side of the wood, but in the design materials PW _{D1 and} PW _D2 , the cross grain surface or the chamfered surface on the front side of the wood is the pressed surface. Therefore, even if there are knots in the highly compressed design materials PW _{D1 and} PW _D2 , the compression force in the direction perpendicular to the length direction of the wood grain is applied to the low-compression inner layer material PW _I. It is easy to press and deform the softened part. Therefore, even if knots are present in the highly compressed design materials PW _{D1 and} PW _D2 , the low-compression inner layer material PW _I overlaid on them makes it difficult for the movement of the knots due to the thermal compression force to be restrained. High surface hardness and strength due to the high compression of the materials PW _{D1 and} PW _D2 can be combined with a design surface in which cracks such as cracks and fissures at the knots K are unlikely to occur.

In addition, in the laminated plastic-worked wood LPW according to the present embodiment, the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I are laminated with the grain length direction aligned with each other. Even when a certain material is used, the compression stress applied to the knot portion K can be reduced because the knots can easily press against the wood structure of the opposing mating material that is laminated during heat compression. Therefore, when there are many knots, for example, when knots exist at a high occupancy of 10% to 20% and the difference in partial specific gravity is large, when there are knots penetrating the front and back of the wood, or when there are knots with a diameter of 20 mm or more Even if there are knots, cracks and fissures are less likely to occur at the knots and their surroundings.

As shown in FIGS. 1 to 4, in the laminated plastic-worked wood LPW obtained by consolidating a material having knots in this way, the hard parts of the knots K of the wood NW are opposed to each other, i.e., , By pressing a soft portion of another piled wood NW that is easy to soften and deform without knots, a knot K is formed at one or more locations on the facing surfaces of the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I. It has a joint surface BF formed by a convex portion P and a concave portion D deformed by a knot portion K.

Then, by consolidating the wood NW using a material with knots, convex portions due to the knots K are formed on one or more of the facing surfaces of the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I. In the laminated plastic processed wood LPW having a joint surface BF formed by P and a concave portion D deformed at the knot K, the knots are hard, so the internal resistance is high, so the heating compression force is concentrated on the design materials PW _{D1 and} PW _D2 . This makes it possible to increase the density and specific gravity of the design materials PW _{D1 and} PW _D2 and increase the surface hardness and strength.
That is, at least one of the facing surfaces of the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I has a joint surface BF formed by a convex portion P formed by the knot K and a concave portion D deformed by the knot K. Laminated plastic processed lumber LPW provides higher surface hardness and strength. As a result, the surface is resistant to small, shallow scratches caused by writing, cutters, etc., and is suitable for use as a top plate for school children's desks, home study desks, office desks, dining table desks, etc., which are prone to such scratches. is.
In addition, the joint strength can be increased by biting into the laminated mating member of the knot portion K, and the mechanical strength of the entire laminated plastic-worked wood LPW can also be improved.

In addition, in the laminated plastic-worked wood LPW of the present embodiment, the design materials PW _{D1 and} PW _D2 on the front and back sides are densely compacted, so that moisture can be absorbed and released when the ambient environmental conditions change. is suppressed, the dimensional and shape stability is high even if the ambient environmental conditions change. That is, even if the thickness is reduced from the original lumber by consolidation, distortion hardly occurs, and even if the thickness is thin, distortion hardly occurs. Therefore, even if the total weight is small and the thickness is small, high surface hardness and strength can be obtained. Therefore, even if it is used for a top board, a shelf board, or the like, it is possible to increase the degree of freedom in designing supporting members such as legs for supporting them.

In particular, the design materials PW _{D1 and} PW _D2 of the laminated plastic-worked wood LPW of the present embodiment are arranged such that the cross grain surface or chamfered surface on the front side of the wood is a pressed surface. That is, the front and back surfaces of the laminated plastic-worked wood LPW are the cross grain surface or the chamfered surface on the wood surface side, and the cross grain surface or the chamfered surface on the wood surface side is pressed by a pair of press plates 10A and 10B during heat compression. It faces the press plates 10A and 10B. Therefore, since it is compressed in the direction of compression where the amount of strain and internal resistance due to compression are small, even if there are many knots, crushing, _breakage , _cracking , etc. of the knots are unlikely to occur. It becomes possible to concentrate the compressive force more and increase the surface hardness and strength of the design materials PW _{D1 and} PW _D2 . In addition, the anisotropy of shrinkage is balanced between the front and back surfaces of the design materials PW _{D1 and} PW _D2 . Therefore, distortion due to heat compression is unlikely to occur, and even if there are knots, internal cracks are unlikely to occur, and the dimensional and shape stability is high even if the ambient environmental conditions change. Furthermore, the multilayer structure in which the inner layer material PW _I is sandwiched in parallel between the design materials PW _{D1 and} PW _D2 having a higher compression density than the inner layer material PW _I provides mechanically stable strength.

In the laminated plastically processed wood LPW obtained by laminating a plurality of wood NWs and consolidating them in this way, even if one of the design materials PW _{D1 and} PW _D2 or the inner layer material PW _I uses a material with knots, By using a knotless material for the other of the design materials PW _{D1 and} PW _D2 , the surface design of the used surface can be maintained.

Here, according to the experimental research of the present inventors, the laminated plastic processed wood LPW of the present embodiment has an annual ring line RL appearing on the butt end surface of the design materials PW _{D1 and} PW _D2 Tree-ring angle θ _D , which is an acute-angle crossing angle with the straight face, and sharp-angle crossing between the tree-ring line RL appearing on the butt surface of the inner layer material PW _I and the cross-grain surface or straight-square face of the back side of the tree. An annual ring angle θ _I that is an angle preferably satisfies θ _D <θ _I . The annual ring angle θ _D , which is the acute angle of intersection between the tree ring line RL appearing on the butt surface of the design materials PW _{D1 and} PW _D2 and the cross grain surface or chamfered surface of the back side of the tree, and the butt surface of the inner layer material PW _I Design materials PW D1 and PW _D2 are design materials PW _{D1 and} PW _D2 that have a relationship of θ _D < θ _I between the tree-ring line RL that appears and the angle of intersection of the acute angle formed by the cross-grain surface or straight-edge surface on the back side of the tree. Since the heat compressive force concentrates on the design materials PW _{D1 and} PW _D2 and the amount of compressive deformation of the design materials PW D1 and PW D2 is large, high surface hardness can be obtained. In addition, the internal resistance of the timbers NW _{D1 and} NW _D2 of the front and back layers during heat compression is small, the internal stress generated during heat compression is small, and the heat compression force applied to the inner layer material PW _I can be reduced, so many knots are present. For example, when knots exist at a high occupancy of 10% to 20% and the difference in partial specific gravity is large, when there are knots penetrating the front and back surfaces of the wood NW, or when there are knots with a diameter of 20 mm or more. Even in this case, cracks such as cracks and fissures are less likely to occur at the knots and their surroundings.

Furthermore, according to the experimental research of the present inventors, the laminated plastic processed wood LPW of the present embodiment has an annual ring line RL appearing on the butt end surface of the design materials PW _{D1 and} PW _D2 The annual ring angle θ _D , which is the intersection angle on the acute angle side formed by the inner layer material PW _I , is within the range of 0° < θ _D ≤ 30°, preferably 0° < θ _D ≤ 20°. The annual ring angle θ _I , which is the intersection angle on the acute side formed by the appearing tree ring line RL and the cross-grain surface or chamfered surface of the back side of the tree, is 5°≦θ _I ≦80°, preferably 10°<θ _D ≦70°. is preferably within the range of Within this range, the design materials PW _D1 and PW _D2 are subjected to a large amount of compressive deformation due to the concentration of heating and compression forces on the design materials PW _{D1 and} PW _D2 , so that a high surface hardness can be obtained. In particular, the specific gravity of the surface can be made higher than the specific gravity of the whole, and lightness, surface hardness, and strength can be achieved at the same time. In addition, since the internal resistance of each wood NW during heat compression is small and the internal stress generated during heat compression is small, buckling deformation of the annual ring line RL due to heat compression is prevented, and internal cracks such as cracks and fissures are prevented. is difficult to occur. Then, when many knots exist, for example, when knots exist at a high occupancy rate of 10% to 20% and the difference in partial specific gravity is large, or when there are knots penetrating the front and back surfaces of the wood NW, Even if there are knots with a diameter of 20 mm or more, cracks and fissures are less likely to occur at the knots and their surroundings.

As for the annual ring angles θ _D and θ _I , ideally, for lumber without knots K, the intersection between all the annual ring lines RL appearing on the butt surface and the cross-grain surface or straight-line surface on the back side of the tree is This corresponds to the angles θ _D and θ _I , but this is a natural object, and in wood with a knot K, the annual ring line RL is disturbed around the knot K. For example, Where there are no knots, annual rings consisting of early wood and late wood are arcuate, but where there are knots, the knots are oriented substantially perpendicular to the length of the wood grain so as to change the flow of the annual rings. Practically, it is not required that all tree ring lines RL appearing on the buttress surface strictly meet the above angle conditions. Even if there are several tenths of tree ring lines RL that are not aligned, there is no problem as long as the average value satisfies the above angle conditions.

By the way, in order to ensure the smoothness of the final product, one or both of the front and back surfaces of the laminated plastic processed wood LPW _P after consolidation are usually cut. In machining, it was found that even a difference of 0.5 to 1 mm in the amount of cutting on the surface greatly affects the hardness and strength of the cut surface.
Also, if the design materials PW _{D1 and} PW _D2 are too thin, and if a material with knots is used for the inner layer material PW _I that overlaps them, the pattern of the knots K of the design material PW _D1 is used as the surface to be used. _, may appear on the surface of PW _D2 .

Therefore, according to the earnest experimental research of the present inventors, the thickness of the design materials PW _{D1 and} PW _D2 is preferably the thickness of the inner layer material PW It is in the range of 0.3 to 0.8 times the thickness of _I , and more preferably in the range of 0.4 to 0.6 times. If the thickness is within this range, even if there are knots in the inner layer material PW _I overlaid on the design materials PW _{D1 and} PW _D2 that are used as the surface, the knots and the surroundings of the knots will be darkened or blackened. The resulting shading pattern has a thickness that does not appear on the surfaces of the design materials PW _{D1 and} PW _D2 used as the surfaces to be used, so that the surface design is good and high surface strength and hardness are obtained.

Furthermore, the laminated _plastically worked wood _LPW of the present embodiment preferably has a total thickness of 15 mm or more and 40 mm or less, more preferably 18 mm to 35 mm. The thickness is preferably 1.5 mm or more and 10 mm or less, more preferably 1.5 mm or more and 8 mm or less, and the thickness of the inner layer material PW _I is preferably 6 mm or more and 15 mm or less, more preferably is in the range of 8 mm or more and 13 mm or less. If the thicknesses of the design materials PW _{D1 and} PW _D2 are within this range, even if there are knots in the inner layer material PW _I superimposed on the design materials PW _{D1 and} PW _D2 that are used as the surfaces to be used, the knot portions K pattern is not exposed on the surfaces of the design materials PW _{D1 and} PW _D2 used as the surfaces to be used. In particular, the use of coniferous trees such as cedar and cypress ensures light weight with a thin overall thickness. Therefore, even when it is applied to a desk for children at school, an office, a desk for a dining table at home, a shelf board, or the like, it is possible to increase the degree of freedom in designing supporting members such as legs for supporting it.
Further, the design materials PW _{D1 and} PW _D2 are highly compressed and compacted so that they do not easily absorb and release moisture even if the ambient environmental conditions change.

Here, a wood NW made of cypress wood and having a thickness in the range of 12 to 15 mm was used, and the compression ratio with respect to the air-dried specific gravity of the original wood NW was in the range of 45% to 65%. Two design materials PW _{D1 and} PW _D2 on the front and back, and one inner layer material PW _I compressed at a compression ratio within the range of 10% to 40% with respect to the air dry specific gravity of the original wood NW. A laminated plastic-worked wood LPW _P was produced by laminating and joining, and the front and back sides thereof were cut by 2 mm to 3 mm to form a laminated plastic-worked wood LPW, and the Brinell hardness HB of the laminated plastic-worked wood LPW was measured. For the laminated plastically worked wood LPW, a plurality of pieces having different thicknesses and compression ratios were produced by changing the thickness of the wood used and the cutting thickness, and the Brinell hardness HB of each was measured.

Specifically, the Brinell hardness HB is measured according to the test method for wood of JIS Z 2101, and a steel ball with a diameter of 10 mm is applied from one of the design materials PW _{D1 and} PW _D2 to the prepared laminated plastic processed wood LPW. is press-fitted to a depth of about 0.32 (1/π) mm at a speed of 0.5 mm/min, and the load at that time is divided by the contact area. As for the Brinell hardness, Table 1 shows the highest Brinell hardness HB among the average values measured at 12 points on each piece of wood.
For comparison, the Brinell hardness HB was similarly measured for laminated rubber timber and uncompressed cypress and oak timbers, which are used for the surface layer of the top plate of current school desks.
Table 1 shows the measurement results of these Brinell hardnesses HB.

As shown in Table 1, the laminated plastic processed wood LPW that has been subjected to a predetermined consolidation process has the highest Brinell hardness despite having a smaller specific gravity and lighter weight than laminated rubber lumber, uncompressed cypress and oak. became hard. Therefore, according to this laminated plastic processed wood LPW, lightness and high surface hardness and strength are compatible. Furthermore, it is possible to increase the degree of freedom in designing the legs that support the top board of a desk or the like, a shelf board, or the like. Therefore, it is suitable for use as a top plate of a study desk or the like for school, which requires easy carrying, writing, and resistance to scratching by a cutter or the like. In addition, laminated rubber timber, uncompressed cypress timber, and oak timber are natural timbers, so there is a large variation in characteristics such as hardness and strength, and in quality. Since hardness and strength are increased by consolidation processing, variations in characteristics such as hardness and strength and quality are suppressed, and defective products due to lack of hardness and strength are less likely to occur, increasing commercial value as a top plate. It can be made high.

Thus, the laminated plastically worked wood LPW of the present embodiment has a Brinell hardness of 15N or more and 30N or less, preferably 18N or more and 30N or less, more preferably 18N or more and 25N or less. Within this range, the surface is hard to be scratched by writing, a cutter, or the like, that is, it has a high surface hardness and strength, and is hard to break even if it has knots. In addition, wood whose surface hardness is increased by such a compaction process has the texture of wood's original wood grain and warmth. preferred.

As described above, the laminated plastically worked wood LPW according to the above embodiment is obtained by stacking three or more woods NW in the direction perpendicular to the length direction of the wood grain, and Laminated plastic-worked wood LPW formed by consolidating by heat compression in the vertical direction and integrally joining two thin design materials PW _D1 located on the front and back layers and highly compressed by heat compression. _, PW _D2 , and one or more thick inner layer materials PW _I positioned between the two design materials PW _{D1 and} PW _D2 of the front and back layers and having a lower compression than the design materials PW _{D1 and} PW _D2 . It is something to do.

That is, the laminated plastically worked wood LPW according to the above embodiment is a laminated wood LW formed by laminating a plurality of wood NWs in a direction perpendicular to the length direction of the wood grain of the wood NW. Two design materials PW _{D1 and} PW _D2 , which are plastically worked by heat compression in the vertical direction and are integrally joined, having a large amount of compression by heat compression and a small thickness, are arranged on the front and back layers, One or more inner layer materials PW _I having a smaller compression amount due to heat compression and a greater thickness than the two design materials PW _{D1 and} PW _D2 are arranged between the two design materials PW D1 and PW _D2 . .

Therefore, according to the laminated plastically worked wood LPW according to the above embodiment, the design materials PW _{D1 and} PW _D2 forming the front and back design surfaces are highly compressed, while the inner layer material PW between the design materials PW _{D1 and} PW _{D2 I} is plastic processing with low compression, which can increase the mechanical strength and surface hardness compared to the original _{wood NW} . PW _I is less compressible than the design materials PW _{D1 and} PW _D2 , and since the compression rate is balanced on the front and back, distortion due to compression is less likely to occur, so even if a material with knots is used, the It is difficult to apply a strong compressive force to the joints. In particular, it is a plastic working of the laminated wood LW in which the wood NWs are piled up, and even if the wood NW has knots and there are hard portions with partially different specific gravities, the hard knots cannot be formed by stacking the wood NWs and compressing them under heat. Since the portion can be softened by heating and compression and can be deformed by pressing of a hard node, the portion can receive an excessive compressive stress and internal stress. Therefore, even if there are knots, the knots K are less prone to cracks, fissures, and the like. In addition, it is assumed that the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I are laminated and joined with three or more pieces of wood, and a material with knots is used for the inner layer material PW _I and one of the design materials PW _{D1 and} PW _D2 . However, if the other design materials PW _{D1 and} PW _D2 are made of materials without knots, it is possible to maintain the design in terms of use.

In addition, according to the laminated plastically processed lumber LPW according to the above embodiment, a plurality of lumbers NW are laminated and consolidated to obtain a thickness of one lumber. Since it may be thin, it is possible to shorten the drying time in the drying process before consolidation and reduce the load due to drying. Therefore, even when a material with knots is used, it is possible to prevent knot cracking and knot dropout due to drying, and to improve the yield.

In addition, according to the laminated plastic processed wood LPW according to the above embodiment, the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I are integrally joined to each other. It is possible to prevent peeling at the joint surface due to the occurrence of .

Thus, according to the laminated plastically worked wood LPW according to the above embodiment, even if there are knots in the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I , cracks such as cracks and fissures are unlikely to occur at the knots K. In addition, it is possible to achieve both designability and effective use of materials with knots.

In particular, according to the laminated plastic-worked wood LPW according to the above-described embodiment, the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I are laminated with the grain length direction aligned with each other, so that the knots Even when a certain material is used, the knots are likely to press against the wood structure of the opposing mating material that is laminated during heat compression, and compressive stress is less likely to be applied to the knots. Therefore, when there are many knots, for example, when knots exist at a high occupancy of 10% to 20% and the difference in partial specific gravity is large, when there are knots penetrating the front and back of the wood, or when there are knots with a diameter of 20 mm or more Even if there are knots, it is difficult to cause cracks, fissures, etc. at the knots and their surroundings. Therefore, it is possible to further improve the yield during plastic working.

In addition, in the laminated plastically worked wood LPW according to the above embodiment, each of the design materials PW _{D1 and} PW _D2 and the inner layer material PW _I have the annual ring line RL appearing on the butt end surface of the design materials PW _{D1 and} PW _D2 and the plate on the back side of the wood. Acute angle of annual ring θ _D at which the grain surface or the straight edge surface intersects, and acute angle θ _I at which the annual ring line RL appearing on the butt surface of the inner layer material PW _I intersects with the cross grain surface or the straight edge surface of the back side of the tree. When .theta..sub.D < _.theta.I , the design materials _{PW.sub.D1 and PW.sub.D2} have a large amount of compressive deformation and a small internal stress during heating and compression. Therefore, the strain due to compression is small, and even if there are knots, cracks and cracks do not occur, and a high surface hardness can be obtained.

Furthermore, in the laminated plastic processed lumber LPW according to the above embodiment, each of the design materials PW _{D1 and} PW _D2 has an acute-angled side where the annual ring line RL appearing on the butt end surface intersects with the cross-grain surface or the chamfer surface on the back side of the tree. The annual ring angle θ _D is 0° < θ _D ≤ 30°, and one or more inner layer materials PW _I are divided between the annual ring line RL appearing on the butt surface and the cross grain surface or the straightening surface on the back side of the tree. When the annual ring angle θ _I on the acute angle side where the two intersect is 5°≦θ _I ≦80°, buckling deformation of the annual rings due to thermal compression is small. Therefore, even if there are knots, cracks are unlikely to occur inside the wood, and distortions are unlikely to occur. Therefore, it is possible to stabilize the quality.

In addition, according to the laminated plastically worked wood LPW according to the above embodiment, each of the design materials PW _{D1 and} PW _D2 is arranged such that the cross grain surface or the chamfered surface on the front side of the wood is a pressed surface, so that the compression It is compressed in the direction of compression where the amount of strain and internal resistance due to is small. In addition, since the front and back surfaces of the laminated plastic-worked wood LPW are on the front and back surfaces of the design materials PW _{D1 and} PW _D2 , the anisotropy of shrinkage is well-balanced. Therefore, even if there are knots, internal cracks are unlikely to occur, and the dimensional shape stability is high.

In the laminated plastically processed lumber according to the above embodiment, if the air-dried specific gravity is 1.2 times or more and 1.7 times or less than the air-dried specific gravity of the original lumber, surface hardness, strength and lightness are achieved. make it possible to achieve both

In particular, according to the laminated plastic-worked wood LPW according to the above embodiment, the design materials PW _{D1 and} PW _D2 can be compressed by heating to achieve a compression rate within the range of 45% to 65% with respect to the air-dried specific gravity of the original wood NW. The compression rate of the inner layer material PW _I is within the range of 10% to 40% in terms of compression rate with respect to the air-dried specific gravity of the original wood NW by heat compression, so it is high even if it is lightweight using softwood. Surface hardness is obtained. Therefore, both lightness and high surface hardness can be achieved.

In addition, in the laminated plastic processed wood LPW according to the above embodiment, if the thickness of the design materials PW _{D1 and} PW _D2 is within the range of 0.3 to 0.8 times the thickness of the inner layer material PW _I , use Even if there is a knot K in the inner layer material PW _I overlaid on one of the design materials PW _{D1 and} PW _D2 , which is the face side, the darker and blacker pattern around the knot and the knot is the design of the used side. The thickness is such that it does not appear on the materials PW _{D1 and} PW _D2 , and the surface hardness can be increased. Therefore, it is possible to achieve both surface hardness/strength and surface design.

Furthermore, in the laminated plastically worked wood LPW according to the above embodiment, the overall thickness is in the range of 15 mm or more and 40 mm or less, and the thickness of the design materials PW _{D1 and} PW _D2 is in the range of 1.5 mm or more and 10 mm or less. In the case where the thickness of the _inner layer material _{PW I} is within the range of 6 mm or more and 15 mm or less, the _knot K Even if there is a knot and a darkened or blackened pattern around the knot, the thickness is such that it does not appear on the design materials PW _{D1 and} PW _D2 that are used on the side of use, and the overall thickness is thin and lightweight. , high surface hardness is ensured. Therefore, it is possible to achieve both surface hardness/strength, surface design and light weight.

In the laminated plastically worked wood LPW according to the above embodiment, if the Brinell hardness is in the range of 15 N or more and 30 N or less, the surface hardness is such that shallow and fine scratches are difficult to be caused by writing, cutters, etc. It is also suitable as a top board for school children's desks, home study desks, office work desks, dining table desks, and the like.

In the laminated plastically worked wood LPW according to the above embodiment, one or more of the facing surfaces of the design materials PW _D1 , PW _D2 and the inner layer material PW _I are provided with a convex portion P by the knot K and a knot K Even if there is a joint surface BF with a deformed concave portion D, the movement of the joint is not restricted or restrained due to the softening and deformation of the wood structure around it, and cracks such as cracks and fissures occur at the joint K. It is compacted without entering. Therefore, the use of knotted material is less expensive. In addition, wood with knots is difficult to compress and resists compression, so it is possible to increase the surface hardness.

By the way, in the case of forming a product such as a predetermined wide or long top board or shelf board, a plurality of laminated plastic processed lumber LPWs are arranged in parallel with the length direction of the wood grain, and are arranged in the thickness direction. In the vertical direction of the width, that is, in the horizontal direction, and jointed horizontally to have a predetermined width, or in the length direction of the wood grain, that is, in the longitudinal direction, a plurality of laminated plastic-worked lumber LPWs are connected. It is possible to form a predetermined length dimension by splicing and splicing. At this time, a plurality of laminated lumber LW before processing may be jointed horizontally in the width direction perpendicular to the length direction of the grain and/or may be vertically jointed in the length direction of the wood grain for consolidation. good. Laminated plastic processed wood LPW has moisture absorption and desorption characteristics when the ambient environmental conditions change due to the presence of the design materials PW _D1 and PW _D2 that are highly compressed, that is, there is little change in expansion and contraction, and the dimensional shape stability is improved. Therefore, even if a plurality of laminated plastic-worked lumber LPWs are jointed horizontally or longitudinally, a load is applied to the joint surfaces due to changes in ambient environmental conditions, and cracks and distortions are unlikely to occur. In addition, since a large stress is less likely to occur due to changes in ambient environmental conditions, cracks, distortions, etc. of the wood are less likely to occur even when the knots K are present.

By the way, since there is an abundant resin content in the knots and their surroundings, there is a risk that resin will precipitate when excessive heat compression force is applied there, but the lamination plastic working of the above embodiment According to the wood LPW, excessive stress does not easily enter the knots K, so that a large amount of tar deposits from the knots K can be suppressed. Therefore, even if there is a knot K, there is no fear that the resin from the knot K will adhere to the press platen 10 or the like used for heat compression and contaminate the pair of press plates 10, and the laminated plastic processed lumber after the compaction process. A situation in which the LPW cannot be separated from the pair of press plates 10 does not occur. In addition, since the knots K are not highly compressed, there is no chance that a large amount of tar will deposit from the knots K when the ambient environmental conditions change after commercialization, resulting in a decrease in commercial value.

In the above-described embodiment, heat compression is performed by surface contact between the upper press platen 10A and the lower press platen 10B. Since there is little return later, we can stably provide high-quality products.
However, when carrying out the present invention, the consolidation process is not limited to the manufacturing method described above, and may be, for example, manufacturing using compression rollers or rolling rolls.

Since the plastically worked wood PW of the present embodiment has high surface hardness and strength, it also has high abrasion resistance and impact resistance, and is suitable for uses other than top boards and shelf boards. That is, it can be applied not only to desk tops and shelf boards such as school study desks, children's desks, and dining tables, but also to furniture, kitchen boards, stair boards, floors, decks, waistboards, and the like.
It should be noted that the numerical values given in the embodiments of the present invention do not indicate critical values, but indicate preferred values suitable for implementation, so even if the above numerical values are slightly changed, the implementation is denied. is not.

LPW Laminated plastic processed wood NW _D1 , NW _D2 , NW _I1 , NW _I2 , NW _I3 Wood before processing PW _D1, PW _D2 Design material PW _I1 , PW _I2 , PW _{I3 Inner} layer material RL Annual ring line Convex part P
Concave part Q
Joint surface BF

Claims (11)

Laminate plasticity in which three or more pieces of wood are laminated in the direction perpendicular to the length direction of the wood grain, consolidated by heat compression in the direction perpendicular to the length direction of the wood grain, and integrally joined. processed wood,
Two design materials of thin front and back layers highly compressed by the heat compression,
one or more thick inner layer materials sandwiched between the two design materials and having a lower compression than the design materials;
Laminated plastic processed lumber, characterized by comprising: 2. The laminated plastically processed lumber according to claim 1, wherein the design material and the inner layer material are laminated with the wood grains aligned in the length direction. 3. The laminated plastic processed lumber according to claim 1 or 2, wherein each of the design materials is arranged such that a cross grain surface or a chamfered surface on the wood front side is a pressed surface. 4. The laminated plastic processed lumber has an air-dried specific gravity in the range of 1.2 times or more and 1.7 times or less than the air-dried specific gravity of the original lumber. 3. Laminated plastic processed lumber according to claim 1. The design material and the inner layer material are separated from each other by the tree ring angle θ _D on the acute side where the growth ring line appearing on the butt surface of the design material intersects with the cross grain surface or the chamfered surface of the back side of the tree, and on the butt surface of the inner layer material. 5. The tree ring angle θ _I on the acute side where the appearing tree ring line intersects with the cross grain surface or the straight surface of the back side of the tree satisfies θ _D <θ _I. 1. Laminated plastic processed wood according to one. In the design material, the annual ring angle θ _D on the acute angle side where the growth ring line appearing on the butt surface and the cross grain surface or the straight surface on the back side of the tree intersect is 0°<θ _D ≦30°, and the inner layer material is 1 to claim 1, characterized in that the annual ring angle θ _I on the acute angle side where the tree ring line appearing on the butt surface intersects with the cross grain surface or the straight surface on the back side of the tree is 5° ≤ θ _I ≤ 80°. Item 6. The laminated plastically processed lumber according to any one of items 5. The laminated plastically processed lumber has an overall thickness of 15 mm or more and 40 mm or less, and the design material has a thickness of 1.5 mm or more and 10 mm or less, and the single inner layer material or the 7. The laminated plastically processed lumber according to any one of claims 1 to 6, wherein the thickness of each of the two or more inner layer materials is in the range of 6 mm or more and 15 mm or less. 8. The design material according to any one of claims 1 to 7, wherein the design material has a thickness within a range of 0.3 to 0.8 times the thickness of the inner layer material. Laminated plastic processed wood. 9. The laminated plastically processed lumber according to claim 1, wherein the laminated plastically processed lumber has a Brinell hardness in the range of 15N to 30N. The design material has a compressibility within the range of 45% to 65% relative to the air-dried specific gravity of the original wood due to the heat compression, and the inner layer material has the air-dried specific gravity of the original wood due to the heat compression. 10. The laminated plastically processed lumber according to any one of claims 1 to 9, wherein the compressibility is in the range of 10% to 40%. 1 to 4, characterized in that at least one of the facing surfaces of the design material and the inner layer material has a joint surface formed by a convex portion formed by a knot portion and a concave portion deformed by pressing of the knot portion. The laminated plastically processed lumber according to any one of claims 10 to 14.

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