WO2019235503A1

WO2019235503A1 - Plastic working wood

Info

Publication number: WO2019235503A1
Application number: PCT/JP2019/022252
Authority: WO
Inventors: 隆行伊藤
Original assignee: 後藤木材株式会社
Priority date: 2018-06-05
Filing date: 2019-06-05
Publication date: 2019-12-12
Also published as: JP6450489B1; JP2019209590A

Abstract

The purpose of the present invention is to provide plastic working wood that has mechanical strength higher than that of original wood and has no cracks even where knots exist. Plastic working wood PW comprises: a surface layer part F of a high-density deep color region that is caused to have compressibility in the range of 45% to 65% as compressibility relative to an air-dry density of original wood DW by heating compression in a direction perpendicular to a length direction of the grain of the wood; a rear layer part R of a middle-density deep color region that is caused to have compressibility lower than that of the surface layer part F in the range of 15% to 40% as compressibility relative to the air-dry density of the original wood DW by heating compression on a side of a surface opposite to the surface layer part F; and an inner layer part I of a low-density pale region that is interposed between the surface layer part F and the rear layer part R and caused to have compressibility lower than those of the surface layer part F and the rear layer part R in the range of 10% to 30% as compressibility relative to the air-dry density of the original wood DW by heating compression. The plastic working wood PW has bending points f1 and f2 of annual ring lines RL formed at a boundary between the surface layer part F and the inner layer part I and a boundary between the inner layer part I and the rear layer part R at an end surface.

Description

Plastic processed wood

The present invention relates to plastic-processed wood in which a compressive force is applied in the thickness direction to soft wood such as cedar, and in particular, cracks (cracks) occur even when there are nodes. The present invention relates to plastically processed wood with improved mechanical strength.

From the viewpoint of global warming due to the recent decline in tropical rainforests and the protection of the global environment, in particular, in response to the serious depletion caused by the rough cutting of hardwood resources such as lauan used in conventional wood plywood, There is a demand for the development of wood materials other than timber. In Japan, conifers such as cedar and firewood are relatively stable and easily available through planned logging and thinning. Studies have been actively conducted on the effective use of conifers such as cedar and firewood.

However, timbers of conifers such as cedar and oak are softer and lower in strength than timbers of broad-leaved trees such as lauan, so it is difficult to use them as an alternative material such as lauan as it is.
Therefore, for those having low density and lacking in strength and hardness, such as cedar and firewood, for example, as disclosed in Patent Document 1 and the like in which the inventor has previously obtained a patent. It has been put to practical use as a building material, furniture material, etc. by improving the strength characteristics by compressing and densifying.

Here, when wood is used as a building material, furniture material, etc., conventionally, there has been a tendency that wood having no knots is preferred in terms of workability and appearance. However, due to the diversification of consumer preferences in recent years, knotted timber has a natural pattern and texture that seems to be natural timber, and knotted timber has the goodness of feeling the original tree. The number of consumers who choose is increasing. In particular, there are more nodes in coniferous logs such as cedars and firewoods than in hardwood logs that have been used for conventional plywood. It is desirable to establish a technology that can make use of knotted wood rather than selectively removing wood with knots.

However, the section of wood has a high specific gravity and is very hard. In addition, there is anisotropy in the compressive strength of wood, and in particular, compression in the fiber direction of the wood (longitudinal compression, pressurization of the mouth end) and compression in the direction perpendicular to the fiber direction of the wood (radial compression, The size of the strain against the compressive stress is greatly different from the pressure on the grain surface, and the fiber direction of the wood (longitudinal compression, pressure on the mouth end) is difficult to compress, but perpendicular to the fiber direction of the wood The direction (radial compression, pressurization of the grain surface) is easy to be compressed, and the nodes of the wood have their fiber running directions perpendicular to the fiber direction of the wood grain.
Therefore, in addition to the nodes having high specific gravity and hardness, for example, in compression (radial compression, pressurization of the grain surface) in which a compression force is applied in a direction perpendicular to the fiber direction of the wood, the nodes are applied in the direction of the compression force applied. The knot portion is extremely difficult to be compressed even from the anisotropy of the compressive strength due to the difference in the fiber strike between the grain of the annual ring and the knot portion.

For example, as shown in FIG. 3A, in the case of a node on the grain side (near the center of the grain material) that is substantially tangent to the annual ring in the grain material, the node is the grain of the annual ring. Exists in a direction perpendicular to the fiber direction (orthogonal direction with respect to the grain surface), and the fiber of the node runs in a direction orthogonal to the annual rings of the wood that appears in a mountain shape on the end face.
Therefore, when the entire thickness of the grain material is compressed in a direction perpendicular to the fiber direction of the annual ring using a pair of hot plate presses (radial direction compression, pressure on the grain surface), the compression direction If there is a hard node in which the fiber runs, a large compressive stress is generated because the portion of the node is difficult to be compressed. In addition, relatively large compressive stress is likely to occur in the vicinity of the nodes because the fiber running direction of the annual rings is disturbed and inclined. Accordingly, when an excessive compressive force is applied in the fiber direction of the node, the fiber of the node and the surrounding wood are buckled or broken, and a crack (crack) or the like is generated in the node. Furthermore, cracks are also generated in the fiber direction of the plate face due to the spread of cracks (cracks, cracks) around the nodes.

Also, for example, as shown in FIG. 4A, in the case of a node on the wood grain side (a memorial part near the edge of the grain surface) where the annual rings are substantially parallel in the grain material, the node is In addition, it exists in a direction perpendicular to the fiber direction of the grain of the annual ring (perpendicular to the plane of the plate), but the fiber direction of the node is inclined.
For this reason, for example, when compressing the entire thickness of the plate material in a direction perpendicular to the fiber direction of the annual ring using a pair of hot plate presses (radial compression, pressurization in the plate surface direction), A relatively large compressive stress is generated because it is difficult to be compressed in the hard node portion, and a relatively large compressive stress is easily generated in the vicinity of the node due to disturbance in the fiber running direction of the grain of the annual ring and an inclination. Therefore, when an excessive compressive force is applied to the node portion, the inclination of the fiber of the node increases and cracks (cracks, cracks) and the like occur in the wood. In particular, when a high compressive force is applied, cracks (cracks) reach the wood surface.

Therefore, regarding the utilization of wood with knots, in Patent Document 2, a recess is formed by cutting out the lower position of the knot portion on the back side of the wood where knots exist, and at the knot portion and other portions. Proposals have been made for consolidation processing in which excessive compression force is not applied to the nodes by making the amount of compression different.

Japanese Patent No. 5138080 (Japanese Patent Laid-Open No. 2007-112029) JP 2010-042529 A

However, in the technique of Patent Document 2, since a part on the back side corresponding to the node of the wood is cut, depending on the cut site and mode, the compression force is uniformly applied to the entire thickness when pressed with a hot plate. The internal stress is biased, and strain and stress are likely to enter the specific part. For this reason, it becomes easy to produce a crack (crack, crack) etc. at the time of the process of heat compression. In addition, the pressure density in the region of the wood structure with nodes and the region of the wood structure without nodes in the width direction of the timber (perpendicular to the thickness direction of the timber) differs due to changes in ambient environmental conditions. There is a difference in shrinkage. For this reason, it is predicted that changes in dimensions and shape such as distortion and deformation are likely to occur due to changes in ambient environmental conditions, and it is also difficult to make the quality of wood properties such as strength constant. In addition, since the dimensional shape of the node is not constant and varies depending on the wood, complicated work is required for measuring the dimensional shape of the node for each wood and specifying the cutting size of the recess corresponding to the node.

Therefore, an object of the present invention is to provide a plastically processed wood having a mechanical strength higher than that of the original wood and having no cracks (cracks, cracks) even when there are nodes.

The plastic-worked wood of the invention of claim 1 is a plastic-worked wood obtained by plastic working of the wood by heat compression in a direction perpendicular to the length direction of the wood grain, and the heat-compressed surface layer portion and The back layer portion on the opposite side has a three-layer structure in which the compression rate is different by a higher compression rate than the inner layer portion interposed between the surface layer portion and the back layer portion, and the surface layer portion that appears on the end surface And an inflection point of an annual ring line at the boundary between the inner layer portion and the boundary between the inner layer portion and the back layer portion.

Here, the heat compression in the direction perpendicular to the wood grain length direction (wood stand direction, stand tree direction) is the fiber direction of the annual ring for lumber that has been cut by planing or remembrance. This means that the area of the timber surface of the wood is reduced by heat compression in which an external force is applied using a press or the like in a direction perpendicular to (the tree stand direction, the tree stand direction). In general, in the case of a grain material, in consideration of the amount of strain due to compression, the area of the wood mouth face is reduced by press-compressing the grain face side of the wood, but the grain face of the wood is press-compressed. It is also possible to determine whether to press-compress the grid surface depending on the type of wood.
In addition, the said grain surface is a material surface cut | disconnected in the tangent direction of the annual ring line in parallel with the fiber direction (length direction of a grain) of the annual ring of wood. In addition, the above-mentioned end face is a material surface cut in a direction intersecting the fiber direction of the annual rings of wood, that is, a material surface cut perpendicularly or obliquely to the fiber direction of the wood. Furthermore, the above-mentioned grid surface is a material surface that is cut in the radial direction (radial direction) of the annual ring line in parallel with the fiber direction of the annual ring of wood. In addition, the above-mentioned memorial (sometimes referred to as “flow” or “half”) refers to a wood removal or wood grain that is intermediate between the mesh and the board. Further, the plastically processed timber obtained by plastic processing of the timber by heat compression in a direction perpendicular to the length direction of the wood grain means that the timber is compacted by compression molding of the timber.

The surface layer portion is a high-density plastic working region having the highest compression rate, and is a region where the air-drying specific gravity and fiber density are increased by the high compression rate. The compressibility of the surface layer portion is preferably 45% or more in terms of the compressibility relative to the original wood density defined later. This is because if the compression ratio is 45% or more, the properties of the wood change and the hardness increases remarkably.
The back layer portion is formed on the opposite surface side to the surface layer portion, and is a medium density plastic working region having a compression rate next to the surface layer portion, which is lower than the surface layer portion, but lower than the inner layer portion. Is a region where the air-drying specific gravity and fiber density are increased by a high compression ratio.
The inner layer portion is a low-density plastic working region having the lowest compression rate, interposed between the surface layer portion and the back layer portion, and is a region having a low air-drying specific gravity and a low fiber density due to the low compression rate.
The surface layer portion, the back layer portion, and the inner layer portion are used to compress at least the surface layer portion and the back layer portion having a three-layer structure having different compression ratios.

The surface layer portion, the back layer portion, and the inner layer portion that are compressed in the surface layer are in a direction perpendicular to the length direction of the wood grain (heat compression direction), that is, in the thickness direction of the wood, the surface layer portion, the inner layer portion, and the back layer. It is the structure which continues integrally in the order of a part. The surface layer part and the inner layer part, and the inner layer part and the back layer part have a clear density difference due to the difference in compression rate, and in the annual ring line that appears on the end of the mouth, on the boundary between the surface layer part and the inner layer part, and A bending point is formed on the boundary between the inner layer portion and the back layer portion.

Here, the annual ring line of the above-mentioned facet means a linear part that is densely formed as seen from the face of the facet, and is a grain that appears on the facet of the face.
And having the bending point of the annual ring line at the boundary between the surface layer part and the inner layer part in the above-mentioned mouth end, the difference in compressibility of the surface layer part and the inner layer part, that is, the difference in the amount of compressive deformation of the cells, The density of the surface layer portion and the inner layer portion is affected by the reduction of voids due to the compressive deformation of cells in the early wood portion, the arrangement of the early wood portion and the late wood portion constituting the annual ring line due to overlapping cell walls, The difference means that there is a point where the curve direction of the annual ring line changes. In other words, the difference in compressibility between the surface layer portion and the inner layer portion due to plastic working appears in the annual ring width composed of the early and late material portions, and the difference in annual ring width is manifested as a bend in the annual ring line on the end of the end. The bending point exists on the boundary between the surface layer portion and the inner layer portion.

In addition, the difference between the compressibility of the inner layer portion and the back layer portion, i.e. The difference affects the reduction of voids due to compressive deformation of cells in the early wood part, the arrangement of the early wood part due to overlapping cell walls and the late wood part constituting the annual ring line, the inner layer part and the back layer part This means that there is a point where the curve direction of the annual ring line changes due to the obvious density difference. That is, the difference in compressibility between the inner layer portion and the back layer portion due to plastic processing appears in the annual ring width composed of the early material portion and the late material portion, and the difference in the annual ring width is bent to the annual ring line on the end of the mouth. It has become apparent, and its bending point exists on the boundary between the inner layer portion and the back layer portion.

The surface layer portion and the back layer portion are the upper and lower layers when the vertical direction is the vertical direction of the wood grain, that is, the thickness direction of the wood. In the thickness direction of the wood, which is perpendicular to the length direction of the grain, the high-density plastic working region having the highest compression rate is the surface layer portion, and the compression rate is lower than the surface layer portion on the opposite side. The medium density plastic working region is the back layer part, and the low density plastic working region with the lowest compression ratio interposed between them is the inner layer part. Where the back layer portion can be recognized, for example, when plastic-worked wood is used as a flooring or the like, the surface layer portion having the highest compression rate is usually set to the use surface and the design surface side. However, the use direction and the design surface side are not necessarily specified up to the use direction as the surface layer side. Further, from the amount of strain due to heat compression, for example, in the case of a grain material, the grain surface side on the wood front side is the surface layer part side, and the grain surface side on the wood back side is the back layer part side. The tree type of the plastically processed wood is not particularly limited, and may be coniferous or hardwood. For example, cedar, pine (larch, etc.), firewood, firewood, walnut (walnut), yellow poplar, etc. are used. Furthermore, it does not ask about the presence or absence of the nodes of each plastically processed wood.

According to a second aspect of the present invention, the plastically processed wood has a surface layer portion that is a high-density plastic processing region having the highest compression ratio by heat compression in a direction perpendicular to the length direction of the wood grain, and is opposite to the surface layer portion. The back layer portion is a medium density plastic working region with a lower compression rate than the surface layer portion, and the inner layer portion between the surface layer portion and the back layer portion is compressed at a lower compression rate than the surface layer portion and the back layer portion. This is a low-density plastic working region that exhibits a lighter color tone than the surface layer portion and the back layer portion.

The surface layer portion is a high-density plastic processing region having the highest compression ratio, and is a dark-colored region where the air-drying specific gravity and the fiber density are increased due to the high compression rate and the color is darkened. The compressibility of the surface layer portion is preferably 45% or more in terms of the compressibility relative to the original wood density defined later. This is because if the compression ratio is 45% or more, the properties of the wood change and the hardness increases remarkably.
The back layer portion is formed on the opposite surface side to the surface layer portion, and is a medium density plastic working region having a compression rate next to the surface layer portion, which is lower than the surface layer portion, but lower than the inner layer portion. Is a dark color region where the air-drying specific gravity and the fiber density are high due to the high compression ratio.
The inner layer portion is interposed between the surface layer portion and the back layer portion, and is a low-density plastic working region having the lowest compression rate, and because of the low compression rate, the air-drying specific gravity, the fiber density is low, and the surface layer And a light-colored region that exhibits a lighter color tone than the back layer portion.

These surface layer portion, back layer portion and inner layer portion are in the direction perpendicular to the length direction of the wood grain (heat compression direction), that is, in the thickness direction of the wood, in the order of the surface layer portion, the inner layer portion, and the back layer portion. It is a continuous structure. The surface layer part and the inner layer part, and the inner layer part and the back layer part have a clear density difference due to the difference in compression ratio, and the density difference appears as a shade of color tone, and the surface layer part and the back layer compared to the inner layer part. The part exhibits a dark color tone, and the inner layer part exhibits a lighter color tone than the surface layer part and the back layer part. That is, it means that the surface layer portion and the back layer portion appear darker than the inner layer portion on the surface of the end due to a higher compression ratio of the surface layer portion and the back layer portion than the inner layer portion. In other words, the inner layer portion is lighter than the surface layer portion and the back layer portion on the end surface.
The surface layer portion and the back layer portion are the upper and lower layers when the vertical direction with respect to the length direction of the wood grain, that is, when the thickness direction of the wood is the vertical direction. In the thickness direction of the wood, which is perpendicular to the length direction of the grain, the high-density dark color region having the highest compression rate is used as the surface layer portion, and the compression rate is lower than the surface layer portion on the opposite side. Where the medium density dark region is the back layer part, the compression ratio, density, where the surface layer part and the back layer part can be recognized by color tone comparison with the inner layer part, for example, when using plastic working wood as a flooring, etc. The surface layer portion with the highest compression rate is the use surface and the design surface side. However, the use direction and the design surface side are not necessarily specified up to the use direction as the surface layer side. Further, from the amount of strain due to heat compression, for example, in the case of a grain material, the grain surface side on the wood front side is the surface layer part side, and the grain surface side on the wood back side is the back layer part side. The tree type of the plastically processed wood is not particularly limited, and may be coniferous or hardwood. For example, cedar, pine (larch, etc.), firewood, firewood, walnut (walnut), yellow poplar, etc. are used. Furthermore, it does not ask about the presence or absence of the nodes of each plastically processed wood.

The plastically processed wood of the invention of claim 3 is such that the compression ratio of the surface layer portion by the heat compression is in the range of 45% or more and 65% or less in terms of the compression ratio with respect to the air-dry density of the wood, and by the heat compression The compression ratio of the back layer portion is in the range of 15% or more and 40% or less in terms of the compression ratio with respect to the air dry density of the wood, and the compression ratio of the inner layer portion by the heat compression is the air dry density of the wood. The compression ratio is 10% or more and 30% or less.

Here, the compression ratio with respect to the air dry density of the wood is calculated from the air dry density <kg / m ³ > of the original wood and the air dry density <kg / m ³ > of a specific layer of plastic processed wood. And
Compression rate <%>
= [1-[(Air-dry density of original wood) / (Air-dry density of a specific layer of plastic-processed wood)]]]
× 100 ・・ (A)
Is defined by
For example, in plastic working wood made by plastic processing of cedar wood, only the surface layer portion which is a high density dark color area is cut out and taken out, and when the air dry density of the surface layer portion is measured, the air dry density of the surface layer portion is If it is 760 <kg / m ³ >, the air-drying density of cedar is an average of 380 <kg / m ³ >, so the compression ratio of the surface layer portion is 50% from the above formula (A).
And the said compression rate respond | corresponds to the dimension shape of a final product, the air dry density of a final product is measured, and the change from the air dry density of the original timber is computed.

The air dry density is the density of wood when the wood is left in the air, dried to reach the air dry moisture content, and is usually expressed as the density at a moisture content of 15% as the air dry moisture content, It is the weight per unit volume when wood is dried.
For example, the average air dry density of timber cedar, which is often used domestically or domestically, is 380 <kg / m ³ >, and the average air dry density of firewood is 440 <kg / m ³ >. Is 500 <kg / m ³ >, the average air dry density of Dodomatsu is 440 <kg / m ³ >, the average air dry density of Ezo pine is 430 <kg / m ³ >, and the average air dry density of red pine is 520 <kg / m ^3>, the average of tung air-dried density 300 <kg / m ^3>, the average air-dried density 600 <kg / m ³ of chestnut>, the average air-dried density of hiba is 470 <kg / m ^3>, zelkova Has an average air dry density of 690 <kg / m ³ >, walnut air dry density of 470 <kg / m ³ >, beech average air dry density of 650 <kg / m ³ >, and oak average air dry density of 630 <kg / m ^3>, the average air-dried density of chestnut 600 <kg / m ^3>, Hippo Hitoshikiinui density 600 <kg / m ^3>, the average air-dried density of Castanopsis is 610 <kg / m ^3>, the average air-dried density of Karin 610 <kg / m ^3>, the average air-dried density of Farukata is 270 <kg / m ³ > is 0.27, Malapapaia average air dry density is 500 <kg / m ³ >, Gmelina average air dry density is 450 <kg / m ³ >, and rubber average air dry density is The average air dry density of 640 <kg / m ³ >, yellow poplar is 450 <kg / m ³ >, the average air dry density of Italian poplar is 350 <kg / m ³ >, and the average air dry density of acacia mangium is 630. <Kg / m ³ >.

The plastically processed wood of the invention of claim 4 is such that the air dry density of the inner layer part is within a range of 0.35 times or more and 0.65 times or less with respect to the air dry density of the surface layer part, and the back layer part The air-dry density is in the range of 0.6 times or more and 0.8 times or less.
In addition, the measurement of the air dry density is performed by cutting and separating the surface layer portion that is a high density dark color region, the inner layer portion that is a low density light color region, and the back layer portion that is a medium density dark color region, for example. It can be measured.

The plastically processed wood of the invention of claim 5 is the surface layer portion and the back layer of the surface layer portion on both sides and the back layer portion on the opposite side heated and compressed in the direction perpendicular to the length direction of the wood grain. It is a darker color tone than the inner layer part due to a higher compression ratio than the inner layer part interposed between the parts, the boundary between the surface layer part and the inner layer part on the end, and the inner layer part and the back layer part The bending point of the annual ring line on the boundary between the back layer part and the inner layer part has a bending point of the annual ring line on the boundary, and the bending degree of the bending point of the annual ring line on the boundary between the surface layer part and the inner layer part is It is larger than the degree of bending.

Here, the heat compression in the direction perpendicular to the wood grain length direction (wood stand direction, stand tree direction) is the fiber direction of the annual ring for lumber that has been cut by planing or remembrance. This means that the area of the timber surface of the wood is reduced by heat compression in which an external force is applied using a press or the like in a direction perpendicular to (the tree stand direction, the tree stand direction). In general, in the case of a grain material, in consideration of the amount of strain due to compression, the area of the wood mouth face is reduced by press-compressing the grain face side of the wood, but the grain face of the wood is press-compressed. It is also possible to determine whether to press-compress the grid surface depending on the type of wood.
In addition, the said plate grain surface is a material surface cut | disconnected in the tangential direction of the annual ring line in parallel with the fiber direction (wood grain length direction) of the annual ring of wood. In addition, the above-mentioned end face is a material surface cut in a direction intersecting the fiber direction of the annual rings of wood, that is, a material surface cut perpendicularly or obliquely to the fiber direction of the wood. Furthermore, the above-mentioned grid surface is a material surface that is cut in the radial direction (radial direction) of the annual ring line in parallel with the fiber direction of the annual ring of wood. In addition, the above-mentioned memorial (sometimes referred to as “flow” or “half”) refers to a wood removal or wood grain that is intermediate between the mesh and the board. Further, the plastically processed timber obtained by plastic processing of the timber by heat compression in a direction perpendicular to the length direction of the wood grain means that the timber is compacted by compression molding of the timber.

The surface layer portion is a dark color region in which the air-drying specific gravity and the fiber density are increased due to a higher compression ratio than that of the inner layer portion, thereby darkening the color. The compressibility of the surface layer is preferably 45% or more in terms of the compressibility relative to the original wood density. This is because if the compression ratio is 45% or more, the properties of the wood change and the hardness increases remarkably.
The said back layer part is the dark color area | region which was formed in the opposite surface side with respect to the said surface layer part, and air-drying specific gravity and fiber density became high and became dark color with the higher compression rate than the inner layer part.
The inner layer portion is interposed between the surface layer portion and the back layer portion, and the air layer specific gravity and fiber density are low due to a lower compressibility than the surface layer portion and the back layer portion, so that the surface layer portion and the back layer portion are low. It is a light-colored region that exhibits a lighter color tone than the layer portion.

These surface layer portion, back layer portion and inner layer portion are in the direction perpendicular to the length direction of the wood grain (heat compression direction), that is, in the thickness direction of the wood, in the order of the surface layer portion, the inner layer portion, and the back layer portion. It is a continuous structure. The surface layer part and the inner layer part, and the inner layer part and the back layer part have a clear density difference due to the difference in compression ratio, and the density difference appears as a shade of color tone, and the surface layer part and the back layer compared to the inner layer part. The part exhibits a dark color tone, and the inner layer part exhibits a lighter color tone than the surface layer part and the back layer part. That is, it means that the surface layer portion and the back layer portion appear darker than the inner layer portion on the surface of the end due to a higher compression ratio of the surface layer portion and the back layer portion than the inner layer portion. In other words, the inner layer portion is lighter than the surface layer portion and the back layer portion on the end surface.

Further, the annual ring line on the above-mentioned facet means a linear part that is densely formed as viewed from the facet, and is a grain that appears on the facet.
And the annual ring line on the end of this end is a bending point on the boundary between the surface layer portion and the inner layer portion that can be distinguished by the difference in shade, and on the boundary between the inner layer portion and the back layer portion that can also be distinguished by the difference in shade. Have

Here, having a bending point of an annual ring line at the boundary between the surface layer portion and the inner layer portion in the above-mentioned mouth end means that the difference in compressibility between the surface layer portion and the inner layer portion, that is, the difference in the amount of compressive deformation of cells. The effect of the reduction of voids due to compressive deformation of cells in the early wood part, the arrangement of the early wood part and the late wood part constituting the annual ring line due to the overlap of the cell wall, and is apparent in the surface layer part and the inner layer part This means that there is a point where the curve direction of the annual ring line changes due to the density difference. In other words, the difference in compressibility between the surface layer portion and the inner layer portion due to plastic working appears in the annual ring width composed of the early and late material portions, and the difference in annual ring width is manifested as a bend in the annual ring line on the end of the end. The bending point exists on the boundary between the surface layer portion and the inner layer portion.

In addition, the difference between the compressibility of the inner layer portion and the back layer portion, i.e., the amount of compressive deformation of the cells, also has an inflection point of the annual ring line at the boundary between the inner layer portion and the back layer portion on the above-mentioned butt face. The difference affects the reduction of voids due to compressive deformation of cells in the early wood part, the arrangement of the early wood part due to overlapping cell walls and the late wood part constituting the annual ring line, the inner layer part and the back layer part This means that there is a point where the curve direction of the annual ring line changes due to the obvious density difference. That is, the difference in compressibility between the inner layer portion and the back layer portion due to plastic processing appears in the annual ring width composed of the early material portion and the late material portion, and the difference in the annual ring width is bent to the annual ring line on the end of the mouth. It has become apparent, and its bending point exists on the boundary between the inner layer portion and the back layer portion.

And the bending degree of the bending point of the annual ring line on the boundary between the surface layer part and the inner layer part is larger than the bending degree of the bending point of the annual ring line on the boundary between the back layer part and the inner layer part. In the surface layer portion, the annual ring width is reduced as compared with the inner layer portion due to a higher compression ratio than the inner layer portion, and in the back layer portion, the annual ring width is reduced in the inner layer portion due to a higher compression rate than the inner layer portion. Compared to the boundary between the surface layer portion and the inner layer portion that can be differentiated by shading, and on the boundary between the inner layer portion and the back layer portion that can be distinguished by shading, Although it appears in the form of a bent line, the compression rate of the back layer part is higher than that of the surface layer part. Larger than the change in annual ring width reduction, the difference in these changes is the difference in flexion change Means that bending of the annual ring lines of the superficial layer relative to annulus line of the inner portion than the bending of the annulus line of the backing layer portion is larger with respect to annulus line of the inner portion. That is, the annual ring line of the surface layer portion that appears in the mouth due to the high compression rate of the surface layer portion has a gentle slope, whereas the back layer portion has a lower compression rate than the surface layer portion, Since the slope of the annual ring line of the back layer part that appears is a steep slope, the change in the bending of the annual ring line from the inner layer part side to the surface layer part side that appears in the clump is the inner layer part side to the back layer part side It is steeper than the change in annual ring line.

In addition, in the thickness direction of the wood that is perpendicular to the length direction of the grain, on the boundary between the surface layer part and the inner layer part and among the annual ring lines on the boundary between the inner layer part and the back layer part, The higher the degree of bending is on the boundary side between the surface layer part and the inner layer part, and the degree of bending of the annual ring line and the color comparison with the inner layer part can recognize the surface layer part and the back layer part. In general, the degree of bending of the annual ring line is large, and the change of the annual ring line from the inner layer side to the surface layer side is steep, that is, the compression rate is higher than that of the back layer part. The surface layer portion is the use surface and the design surface side. However, the use direction and the design surface side are not necessarily specified up to the use direction as the surface layer side. Also, from the amount of strain due to heat compression, for example, in the case of a grain material, the grain surface side on the wood surface side is the surface layer part side, and the plate surface side on the tree back side is the back layer part side. And a surface layer part and a back layer part are the perpendicular | vertical direction with respect to the length direction of the grain of a timber, ie, the upper and lower layers, when the thickness direction of a timber is made into an up-down direction. The tree type of the plastically processed wood is not particularly limited, and may be coniferous or hardwood. For example, cedar, pine (larch, etc.), firewood, firewood, walnut (walnut), yellow poplar, etc. are used. Furthermore, it does not ask about the presence or absence of the nodes of each plastically processed wood.

In the plastically processed wood of the invention of claim 6, the density distribution in the thickness direction from the surface layer portion side to the back layer portion side on the opposite surface side is from the surface side of the surface layer portion and the back surface side of the back layer portion. The density gradually changes from a high state to a low state toward the center side of the inner layer portion. That is, there is a clear density difference between the surface layer portion and the inner layer portion, and the inner layer portion and the back layer portion, but in each surface layer portion, inner layer portion, and back layer portion, the density distribution is not uniform, Their density is higher as they are closer to the surface of the surface layer portion or the back surface of the back layer portion, and gradually decreases toward the inside of the wood.

The plastic-worked wood of the invention of claim 7 is such that the thickness of the inner layer portion is within a range of 2 times or more and 5 times or less with respect to the thickness of the surface layer portion, and the thickness of the back layer portion is 0.5 times or more. 1 or less. In addition, each surface layer part, inner layer part, and back layer part can be distinguished by the difference in shading on the end face, and their thickness means a thickness perpendicular to the length direction of the wood grain. The thickness at this time is the final product thickness, and when the surface layer portion or the like is cut after plastic working (consolidation), the thickness after the cutting is used as a reference. .

According to the plastically processed wood according to the invention of claim 1, the plastically processed wood is obtained by plastically processing the wood by heat compression in a direction perpendicular to the length direction of the wood grain. A surface layer compression comprising a surface layer portion, the back layer portion, and the inner layer portion at a compression ratio higher than that of the inner layer portion interposed between the surface layer portion and the back layer portion. It is made of a material, and an inflection point of an annual ring line is formed at the boundary between the surface layer portion and the inner layer portion and the boundary between the inner layer portion and the back layer portion that appear on the end face.
The plastically processed wood according to the invention of claim 1 has a surface layer in the thickness direction from the front surface side to the back surface side on the opposite surface side by heat compression in a direction perpendicular to the length direction of the wood grain. Since it is a plastic working material that increases the compression rate on the side and the back layer side, and makes the inside between them a low compression rate, the surface layer side and the back layer side are easily compressed, and the inside of the wood is difficult to be compressed. It is made difficult to be stressed by compression.

Thus, since the plastically processed wood according to the invention of claim 1 has reduced compressive stress in the wood, even if a node is present, an excessive compressive force is applied to the entire structure of the node. It is not done. In particular, excessive stress is not easily applied to the fiber at the node inside the wood. In this way, the inside of the wood is hard to be compressed, but during the heat compression treatment, the fibers of the wood structure soften and deform around the node due to the high moisture absorption and desorption characteristics of the node and the surrounding area. It is easy and the movement of the node due to the heat compression force is not regulated.
In addition, the surface layer compression material consisting of the surface layer portion, the back layer portion, and the inner layer portion has a bent annual ring line at the boundary between the surface layer portion and the inner layer portion and the boundary between the inner layer portion and the back layer portion that appear on the end surface. Although the point is formed, because wood is a natural object, not only the inflection point of the clear annual ring line appears, but also the clear inflection point of the clear annual ring line may not appear depending on the location. .

Therefore, according to the plastically processed wood according to the invention of claim 1, even when there are nodes, it is difficult for excessive stress due to compression to be applied to the nodes and the surrounding fibers within the wood, and the heat compression force Since the stress of the node part due to the occurrence of stress is reduced, the inclination of the node part and its surrounding fibers, buckling, crushing, destruction, etc. are difficult to occur, and cracks in the wood (cracks, cracks) are difficult to occur. .
Further, according to the plastically processed wood according to the first aspect of the invention, the surface layer portion can be used as a high-density plastic processing region having the highest compression rate, so that the ease of scratching of the original wood can be eliminated, and the compression is higher than that of the inner layer portion. The three-layer structure in which the inner layer portion is sandwiched in parallel by the surface layer portion and the back layer portion of the rate provides mechanically stable strength, so that the mechanical strength can be made stronger than the original wood. And the balance of expansion and contraction rate is good on the front and back by sandwiching the inner layer part between the surface layer part and the back layer part having a higher compressibility than the inner layer part. In particular, when the surface of the wood having a large expansion / shrinkage ratio is used as the surface layer portion, the back layer portion on the back side of the wood having a small expansion / contraction rate is plastically processed at a lower compressibility than the surface layer portion. Therefore, the difference in expansion / contraction rate between the front and back of the original wood is balanced. Furthermore, even if the shrinkage and expansion force occurs due to changes in the surrounding environmental conditions due to the high moisture absorption and desorption characteristics of the node and its surroundings, the inner layer is a low-density plastic working region with a low compressibility, so that it has a buffering effect. have. Therefore, even when the ambient environment conditions change, the generation of internal stress is reduced.
Therefore, even when there is a node, there is little stress applied to the node due to a change in the surrounding environmental conditions, and this is a measure that does not cause cracks in the wood. In addition, the occurrence of overall distortion is small, and the dimensional shape stability is high.

According to the plastic processed wood according to the invention of claim 2, the surface layer portion is subjected to high-density plastic processing with the highest compressibility by heat compression in the thickness direction of the wood that is perpendicular to the length direction of the wood grain. And an inner layer portion interposed between the surface layer portion and the back layer portion is formed as a medium density plastic working region having a lower compression rate than the surface layer portion. This is a low-density plastic working region that has a lower compression ratio than the front and back layers and a lighter hue than the surface and back layers.

The plastically processed wood according to the invention of claim 2 has a surface layer in the thickness direction from the front surface side to the back surface side on the opposite surface side by heat compression in a direction perpendicular to the length direction of the wood grain. This is a plastic working that increases the compression ratio on the side and the back layer side and lowers the compression ratio between them, so that the surface layer side and the back layer side are easily compressed, and the inside of the wood is difficult to be compressed, and the inside of the wood is compressed. It is designed to make it difficult to be stressed by.

Thus, since the plastically processed wood according to the invention of claim 2 has reduced compressive stress inside the wood, even if a node is present, an excessive compressive force is applied to the entire structure of the node. It is not done. In particular, excessive stress is not easily applied to the fiber at the node inside the wood. In this way, the inside of the wood is hard to be compressed, but during the heat compression treatment, the fibers of the wood structure soften and deform around the node due to the high moisture absorption and desorption characteristics of the node and the surrounding area. It is easy and the movement of the node due to the heat compression force is not regulated.

Therefore, according to the plastically processed wood according to the invention of claim 2, even when there are nodes, it is difficult for excessive stress due to compression to be applied to the nodes and the surrounding fibers within the wood, and the heat compression force Since the stress of the node part due to the occurrence of stress is reduced, the inclination of the node part and its surrounding fibers, buckling, crushing, destruction, etc. are difficult to occur, and cracks in the wood (cracks, cracks) are difficult to occur. .

Further, according to the plastically processed wood according to the invention of claim 2, the surface layer portion can be used as a high-density plastic processing region having the highest compression rate, so that the ease of scratching the original wood can be eliminated, and the compression is higher than that of the inner layer portion. The three-layer structure in which the inner layer portion is sandwiched in parallel by the surface layer portion and the back layer portion of the rate provides mechanically stable strength, so that the mechanical strength can be made stronger than the original wood. And the balance of expansion and contraction rate is good on the front and back by sandwiching the inner layer part between the surface layer part and the back layer part having a higher compressibility than the inner layer part. In particular, when the surface of the wood having a large expansion / shrinkage ratio is used as the surface layer portion, the back layer portion on the back side of the wood having a small expansion / contraction rate is plastically processed at a lower compressibility than the surface layer portion. Therefore, the difference in expansion / contraction rate between the front and back of the original wood is balanced. Furthermore, even if the shrinkage and expansion force occurs due to changes in the surrounding environmental conditions due to the high moisture absorption and desorption characteristics of the node and its surroundings, the inner layer is a low-density plastic working region with a low compressibility, so that it has a buffering effect. have. Therefore, even when the ambient environment conditions change, the generation of internal stress is reduced.
Therefore, even when there is a node, there is little stress applied to the node due to a change in the surrounding environmental conditions, and this is a measure that does not cause cracks in the wood. In addition, the occurrence of overall distortion is small, and the dimensional shape stability is high.

According to the plastic processed wood according to the invention of claim 3, the surface layer portion has a compression rate within a range of 45% to 65% as a compression rate with respect to an air-dry density of the wood by the heat compression, and the back layer The compression ratio with respect to the air dry density of the wood is a compression ratio within a range of 15% to 40%, and the inner layer portion is 10% to 30% with respect to the air dry density of the wood by the heat compression. % Compression rate within the range of%.

The present inventors do not cause cracks (cracks, cracks) even if there are large nodes or a large number of nodes in the wood, regardless of the difference between the wood grain and the remembrance material, etc. In order to obtain wood characteristics such as strength with stable quality, the result of extensive experimental research, plasticity that controls the compression rate by setting the surface layer part, the back layer part and the inner layer part within a predetermined compression ratio range Regardless of the difference between the wood grain and the remembrance of wood, wood, etc., due to processing, even if the occupancy of the node is as high as 10% to 20%, cracks (cracks), etc. The present inventors have found that a stable quality of wood properties such as strength can be obtained and the yield is high, and the present invention has been completed based on this finding.

That is, for example, in the case of soft wood such as cedar and straw with an air-dry specific gravity of 0.48 or less, the surface layer portion has a compressibility within a range of 45% to 65% in terms of the compressibility relative to the density of the wood, The back layer portion has a compression ratio in the range of 15% to 40% with respect to the wood density, and the inner layer portion has a compression ratio in the range of 10% to 30% with respect to the wood density. By controlling the compression rate of each layer as the rate, in addition to the effect of claim 1 or claim 2, the occupancy ratio of the node portion is obtained regardless of the difference in the wood grain of the plate material, the memorial material, etc. Even if it is as high as 10% to 20%, there are no cracks (cracks, cracks, etc.). It has a stable quality plastic processed wood.

According to the plastically processed wood according to the invention of claim 4, the air dry density of the inner layer portion is within a range of 0.35 to 0.65 times the air dry density of the surface layer portion, and the back layer portion The air dry density is in the range of 0.6 to 0.8 times.
According to the experimental study by the present inventors, in addition to the effect described in any one of claims 1 to 3, by the plastic working in which the air-dry density of each layer is within the above range by heat compression, Overall, the balance of expansion and contraction is good, and the internal stress due to contraction and expansion of wood when ambient environmental conditions change can be reduced. Therefore, even when nodes are present at a high occupancy ratio of 10% to 20% in the wood, the stresses caused by the difference in shrinkage and expansion rate when the ambient environmental conditions change can cause the node K inside the wood. Stable quality is ensured without cracks (cracks, cracks).

According to the plastic-worked wood according to the invention of claim 5, the surface layer portion on both sides and the back layer portion on the opposite side, which are heat-compressed by heat compression in the direction perpendicular to the length direction of the wood grain, Due to a higher compression ratio than the inner layer part interposed between the surface layer part and the back layer part, it exhibits a darker color tone than the inner layer part, and the boundary between the surface layer part and the inner layer part appearing on the top surface There is a bending point of an annual ring line at the boundary between the inner layer part and the back layer part, and the bending degree of the bending point of the annual ring line on the boundary between the surface layer part and the inner layer part is the back layer part and the inner layer part. It is larger than the bending degree of the bending point of the annual ring line on the boundary.

Thus, in the thickness direction from the surface side to the back side of the opposite surface side by heat compression in the direction perpendicular to the length direction of the wood grain, the surface layer part and the back layer part are more than the inner layer part between them Darkening due to high compression rate, and annual rings at the boundary between the surface layer portion and the inner layer portion and the boundary between the inner layer portion and the back layer portion appearing on the end due to the difference in compression rate and density between the surface layer portion and the back layer portion and the inner layer portion. The plastic working that has the bending point of the line is a state in which the surface layer side and the back layer side are easily compressed and the inside is difficult to be compressed, so that the stress inside the wood is not easily applied. In particular, the plastic working in which the bending degree of the annual ring line on the boundary between the surface layer part and the inner layer part is larger than the bending degree of the bending point of the annual ring line on the boundary between the back layer part and the inner layer part Is a heat compression in which the compression ratio and density of the surface layer portion are different from the compression ratio and density of the back layer portion, and the concentration of internal stress is relaxed during the heat compression treatment.

Thus, according to the plastically processed wood according to the invention of claim 5, since the compressive stress in the wood is reduced, even if a node is present, an excessive compressive force is exerted on the entire structure of the node. It is never added. In addition, although the inside of the wood is in a state that is difficult to be compressed, the fibers of the wood structure tend to soften and deform around the nodes due to the high moisture absorption and desorption characteristics of the nodes and the surroundings during the heat compression treatment. The movement of the node due to the compressive force is not regulated.
Therefore, it is difficult for excessive stress due to compression to be applied to the nodes and surrounding fibers inside the wood, and the occurrence of stress in the nodes due to heat compression force is reduced, so the inclination of the nodes and surrounding fibers, Buckling, crushing, breaking, etc. are unlikely to occur, and wood cracks (cracks, cracks) are unlikely to occur.

In addition, the surface layer is made of the highest compressibility high-density plastic processing region, which can eliminate the susceptibility of the original wood to damage, and the inner layer is parallel to the upper and lower layers of the surface layer and the back layer having a higher compressibility than the inner layer. Since the three-layer structure sandwiched between the layers provides mechanically stable strength, the mechanical strength can be made stronger than the original wood. And the balance of expansion and contraction rate is good on the front and back by sandwiching the inner layer part between the surface layer part and the back layer part having a higher compressibility than the inner layer part. In particular, when the surface of the wood having a large expansion / shrinkage ratio is used as the surface layer portion, it is made a high-density plastic processing, while the back layer portion of the wood back side having a small expansion / contraction rate is plastic processing with a lower compressibility than the surface layer portion. Therefore, the difference in expansion / contraction rate between the front and back of the original wood is balanced. Furthermore, even if the shrinkage and expansion force occurs due to changes in the ambient environment due to the high moisture absorption and desorption characteristics of the node and its surroundings, the inner layer is a low-density plastic working region with a low compressibility, so that it has a buffering action. have. Therefore, even when the ambient environment conditions change, the generation of internal stress is reduced.
Therefore, even when there is a node, there is little stress applied to the node due to changes in ambient environmental conditions, and this is a countermeasure that does not cause cracks in the wood. In addition, the occurrence of overall distortion is small, and the dimensional shape stability is high.

According to the plastic processed wood according to the invention of claim 6, the density distribution in the thickness direction from the surface layer side to the back layer side on the opposite surface side is the surface side of the surface layer part and the back layer part. Since the density gradually changes from a high density state to a low density from the back side toward the inside, in addition to any one of claims 1 to 5, the density difference in the thickness direction of the wood Since there is no sudden change, stress concentration due to the difference in contraction and expansion force hardly occurs. Therefore, even when there is a node, stress on the node due to changes in ambient environmental conditions can be reduced, and cracks in the node (cracks, cracks), cracks in the wood, overall distortion, etc. are unlikely to occur.

According to the plastic-worked wood according to the invention of claim 7, the thickness of the inner layer portion is in the range of 2 to 5 times the thickness of the surface layer portion, and the thickness of the back layer portion is 0.5 to 1. Within double range.
According to the experimental study by the present inventors, in addition to the effect described in any one of claims 1 to 6, by the plastic working in which the thickness of each layer is within the above range by heat compression, the tree table Even when a large node with a diameter of 1 cm or more exists in the thickness direction of the wood when measured on the side plate surface or the memorial surface, the compressive stress applied to the node can be reduced, and the fiber of the node and its surroundings can be reduced. Wood cracks (cracks, cracks) due to buckling, breaking, etc. are unlikely to occur. In addition, remarkable darkening and blackening of the node portion and its surroundings due to compression are suppressed, and the surface design is not impaired. In addition, the thickness of the front and back surfaces and the compression ratio are well balanced, and high dimensional shape stability can be ensured even if the surrounding environmental conditions change. Even when there are nodes, the nodes and their surroundings are less likely to crack.

FIG. 1 is an explanatory view showing a plate material as an example of plastic working wood according to an embodiment of the present invention, and (a) is before plastic working for forming the plastic working wood according to the embodiment of the present invention. (B) is a perspective view of the plastic-worked wood according to the embodiment of the present invention, (c) is a front view showing the front end of the wood, the surface layer portion and the back layer portion and the inner layer therebetween It is explanatory drawing which showed the difference of the light and shade with a part, and the strike of an annual ring line. FIG. 2 is an explanatory view showing a memorial material as an example of the plastic working wood according to the embodiment of the present invention, and (a) is before plastic working for forming the plastic working wood according to the embodiment of the present invention. (B) is a perspective view of a plastic-worked wood according to an embodiment of the present invention, (c) is a front view showing the front end of the wood, and a surface layer portion, a back layer portion, and an inner layer portion therebetween It is explanatory drawing which showed the difference of the light and shade, and the strike of an annual ring line. FIG. 3 is an explanatory view of the memorized material shown in FIG. 2 as an example of the plastically processed wood according to the embodiment of the present invention when viewed from the side of the mouth end opposite to FIG. Fig. 2 is a perspective view of the wood before plastic working shown in Fig. 2 when viewed from the side of the mouth end opposite to Fig. 2, and Fig. 2 (b) is the side of the plastic working wood shown in Fig. 2 opposite to Fig. 2. A perspective view when viewed from the side of the mouth, (c) is a front view showing the face of the mouth, showing the difference in light and shade in the surface layer portion and the back layer portion and the inner layer portion therebetween and the running direction of the annual ring line. It is explanatory drawing. FIG. 4 is an explanatory diagram in the case where there is a node as an example of the plastic working wood according to the embodiment of the present invention, and (a) is a plastic working for forming the plastic working wood according to the embodiment of the present invention. The perspective view of the grain material as the previous wood, (b) is a perspective view of the plastically processed wood according to the embodiment of the present invention, (c) is a front view showing the mouth end surface, the surface layer portion and the back layer It is explanatory drawing which showed the difference of the light and dark in an inner layer part between it, and the strike of an annual ring line. FIG. 5 is an explanatory view showing another example in the case where there is a node as an example of the plastic working wood according to the embodiment of the present invention, and (a) shows the formation of the plastic working wood according to the embodiment of the present invention. The perspective view of the grain material as the wood before plastic working to do, (b) is a perspective view of the plastic working wood according to the embodiment of the present invention, (c) is a front view showing the mouth end, It is explanatory drawing which showed the difference of the light and dark in a surface layer part and a back layer part, and the inner layer part in the meantime, and the strike of an annual ring line. FIG. 6 is an explanatory view showing an example of a procedure for forming a plastically processed wood according to an embodiment of the present invention. FIG. 6 (a) is a diagram before plastic working for forming the plastically processed wood according to an embodiment of the present invention. (B) is an explanatory view for explaining drying of wood, (c) is an explanatory view for explaining moisture addition of wood, and (d) is for explaining heat compression of wood. Explanatory drawing, (e) is explanatory drawing of plastic working wood. FIG. 7 is an explanatory view showing an example of a procedure for forming a plastically processed wood according to an embodiment of the present invention. FIG. 7 (a) is a diagram prior to plastic working for forming the plastically processed wood according to an embodiment of the present invention. (B) is an explanatory diagram for explaining drying of the wood, (c) is an explanatory diagram for explaining moisture addition of the wood, and (d) is for explaining heat compression of the wood. Explanatory drawing, (e) is explanatory drawing of plastic working wood. FIG. 8 is a cross-sectional view of a schematic configuration showing an example of a plastic-worked wood manufacturing apparatus for forming plastic-worked wood according to an embodiment of the present invention. FIG. 9 is an explanatory diagram for explaining an example of a manufacturing process of plastically processed wood according to an embodiment of the present invention, where (a) is an explanatory diagram of supply of wood to be plastically processed, and (b) is a heat compression start state. (C) is an explanatory diagram of a heat compression state in a sealed state, (d) is an explanatory diagram of a vapor pressure control process in a sealed state, (e) is an explanatory diagram of a cooled state in a sealed state, ( f) is an explanatory view of taking out the plastically processed wood.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, the same symbols and the same reference numerals mean the same or corresponding parts and functions, and therefore redundant description is omitted here.

For example, as shown in FIGS. 4 (a) and 5 (a), when a node K is present in lumber produced by trimming a raw wood such as a conifer and making a memorial, the node K Since it has a high specific gravity and is harder than tissues other than the node K, the node K is hardly compressed even when a compressive force is applied to enhance the strength characteristics of the wood.
Furthermore, in order to enhance the strength characteristics of the wood due to the anisotropy of the compressive strength of the wood, it is usually pressurized in a direction perpendicular to the fiber direction of the annual ring (the length direction of the grain). When pressure (radial compression) is applied to the grain surface, as shown in FIGS. 4 (a) and 5 (a), the node K of the wood is perpendicular to the length direction of the grain, That is, since the fiber runs in the compression direction, it is strong against compression.
Thus, in addition to the fact that the node K is hard at a high specific gravity, the node K is very difficult to be compressed even from the difference in the direction of fiber running between the annual ring line RL and the node K. .

Therefore, for example, as shown in FIG. 4 (a), in the node K on the wood grain side (near the center of the grain material) that is substantially tangent to the annual ring, the fiber is the length of the wood grain. In order to improve the strength characteristics of the wood, it applies a compressive force from both sides in the thickness direction of the wood using a pair of hot plate presses, etc., in order to improve the strength characteristics of the wood. If the entire thickness is to be highly compressed, the fiber of the node K is caused to run in the compression direction, so that a large compressive stress is generated in the node K, and the fiber of the node K buckles and breaks and cracks (crack, Cracks). Further, even in the vicinity of the node K, the fiber running direction of the annual rings is disturbed, and there are cases where cracks (cracks, cracks, etc.) occur due to the inclination.

Further, as shown in FIG. 5 (a), in the node portion K in the memorial portion, the fiber is inclined in a direction perpendicular to the length direction of the grain (inclined with respect to the grain surface). However, in order to increase the strength characteristics of wood, if a compression force is applied from both sides in the thickness direction of the wood using a pair of hot plate presses or the like to attempt high compression of the entire thickness of the wood, When the fibers of the node K are inclined and run, a relatively large compressive stress is also generated in the node K, the inclination of the fibers of the node K is increased, and cracks (cracks, etc.) are caused in the wood. Arise. Even in the vicinity of the node K, the fiber running direction of the annual ring is disturbed, and the inclination may cause cracks (cracks, cracks).

In particular, in order to obtain a sufficient chemical change for plastic processing by compacting wood, conventionally, the wood is dried to a predetermined moisture content below the fiber saturation point and then compacted. When drying wood, moisture evaporates from the surface side. For this reason, when trying to dry the inside sufficiently as much as the surface side, dry cracking tends to occur on the surface side. Therefore, it will be used for the heat compression process of compaction processing in a state where the moisture content inside is higher than that on the surface side. In particular, when the node K is present in the wood, the moisture absorption and desorption characteristics of the water around the node K are high, so that cracking of the node K (crack, crack), node loss, etc. occur during the drying process. Finally, wood that has been dried to such an extent that cracks in the knots K, breakthroughs, etc. do not occur will have a much higher moisture content on the inside than on the surface side.

And, for the wood having a higher moisture content than the surface side in this way, for example, when a heat compression treatment by surface contact is performed using a pair of hot plate presses, a load is easily applied to the inside of the wood. Local compression deformation tends to occur inside. That is, stress is likely to enter the wood. For this reason, if the node K is present in the wood, excessive stress is applied to the node K inside the wood, so that buckling deformation, crushing, destruction, etc. of the fiber of the node K are likely to occur. Cracks (cracks) are likely to occur inside the wood. This internal crack of the wood may spread to the surface side of the wood.

In addition, since there is an abundance of resin in the node K and its surroundings, when the entire thickness of the wood is highly compressed using a pair of hot plate presses, etc., the node K and its surroundings A large amount of sprout deposits from and adheres to the hot plate press and contaminates the hot plate press. When a large amount of scum adheres to the hot plate press, wood may adhere to the hot plate press and the hot plate press may be difficult to separate from the wood after compression.
Furthermore, when the whole thickness of the wood is highly compressed, the density of the node K on the surface of the wood and the blackening become remarkable due to an increase in the specific gravity of the node K and its surroundings, thereby impairing the design. There was also a problem.

Therefore, the present inventors have repeatedly conducted earnest experimental research in order to obtain plastically processed wood having increased mechanical strength without causing cracks (cracks, cracks) even if there is a node K in the wood. The following problems were solved.

That is, as shown in FIG. 1 to FIG. 5, the compression ratio is highest in the surface layer portion F on both sides in the heat compression direction by heat compression in the direction perpendicular to the length direction of the wood grain. An inner layer having a lower compression ratio than the surface layer portion F and the lower layer portion R between the surface layer portion F and the back layer portion R. By providing the part I and compacting the compression rate, that is, the density, in the thickness direction of the wood, the whole wood is made difficult to receive stress due to compression, and in particular, it is made difficult to apply compressive stress inside the wood. . As a result, even when the node K is present in the wood, the fibers of the node K are not excessively stressed in the wood so that the fibers of the node K are not easily crushed and cracks are generated. Without increasing the mechanical strength.

Specifically, as shown in FIG. 1 to FIG. 5, heat compression is performed in a direction perpendicular to the length direction of the wood grain, that is, in the thickness direction of the wood, and a high compression ratio by heat compression, for example, Compression of the original wood before processing NW1, NW2, NW3, NW4 (hereinafter referred to simply as “Non-processing wood NW” if the pre-processing woods NW1, NW2, NW3, NW4 are not particularly distinguished) The ratio is 30% to 70%, preferably 45% to 65% (calculated from the air dry density corresponding to the size and shape of the final product), and the high specific gravity and fiber density increase due to the high compression ratio. The surface layer portion F of the colored high-density plastic processing region is formed, and the compression rate lower than the surface layer portion F on the side opposite to the surface layer portion F, for example, air drying of the unprocessed wood NW that is the original wood 10% to 45% compressibility against density, good Or within the range of 15% to 40% (calculated from the air dry density corresponding to the size and shape of the final product). The air dry specific gravity is lower than the surface layer portion F but higher than the inner layer portion I due to the higher compression ratio. Forming a back layer portion R of the medium density plastic working region where the fiber density is increased and darkened; and further, a lower compressibility than the surface layer portion F and the back layer portion R between the surface layer portion F and the back layer portion R; For example, the compression ratio with respect to the air-dry density of the unprocessed wood NW that is the original wood is in the range of 5% to 35%, more preferably in the range of 10% to 30% (the air pressure corresponding to the size and shape of the final product). Calculated from the dry density), and the inner layer portion I of the low density plastic working region exhibiting a lighter color tone than the surface layer portion F and the back layer portion R due to a lower compression ratio than the surface layer portion F and the back layer portion R. The formed plastic processed wood PW1, PW2, PW3, PW4 (hereinafter, plastic processed wood PW1, PW2, P 3, when not particularly distinguished PW4 is simply that.) As "plastic working wood PW".

Thus, in the plastic processing in which the density is changed by changing the compression rate in the direction perpendicular to the length direction of the wood grain, that is, in the thickness direction of the wood, stress due to heat compression hardly enters the whole wood, Even if the node K is present, the entire node K is not subjected to excessive compressive force or stress.
In particular, the surface layer part F has the highest compression ratio, the back layer part R opposite to the surface layer part F has a lower compression ratio than the surface layer part F, and is further interposed between the surface layer part F and the back layer part R. The plastic working that makes the inner layer part I the lowest compression rate makes the inner layer part I inside the wood harder to be compressed than the front and back layers side, that is, the load is applied even by planar press compression from above and below. By making the area difficult to hang, and by different compression ratios on the front and back, the stress concentration inside the wood against the heat compression force applied in the thickness direction of the wood has been alleviated, and the compression stress on the wood has been reduced. Is.
Therefore, even when the node K is present in the wood, the entire node K is not subjected to excessive compressive force and stress, and in particular, excessive stress is not applied to the fiber of the node K inside the wood. The buckling, crushing, and destruction of the fibers in the portion K are difficult to occur, and cracks in the wood (cracks, cracks) are difficult to occur.

That is, the surface layer portion F has the highest compression rate, the back layer portion R opposite to the surface layer portion F has a lower compression rate than the surface layer portion F, and is further interposed between the surface layer portion F and the back layer portion R. The plastic working that makes the inner layer part I the lowest compressibility is in a state in which the inner layer part I has the lowest compressibility, so that the inside of the wood is difficult to be compressed, and the compressibility is different between the front and back sides. Since the concentration of internal stress generated in the wood due to the compressive force is relaxed, the strength characteristics are enhanced in a state where there is little compressive stress entering the wood. Thus, the surface layer portion F is set to the highest compression rate, the back layer portion R opposite to the surface layer portion F is set to a compression rate lower than that of the surface layer portion F, and further, between the surface layer portion F and the back layer portion R. According to the plastic working in which the inner layer I intervening in the wood has the lowest compression ratio, excessive stress is not applied to the inside of the wood, and therefore, as shown in FIG. Even when the fiber of the node K runs in a substantially straight line, the node K runs diagonally in a direction perpendicular to the length direction of the wood grain as shown in FIG. Even in the case of being present, excessive stress is not applied to the node K and the surrounding fibers within the wood, so that the inclination, buckling deformation, crushing, and destruction of the node K and the surrounding fibers are unlikely to occur.

And even if it is in a state where stress due to heat compression is not easily applied to the inside of the wood during the heat compression treatment, the wood structure softens and deforms easily around the node K due to its high moisture absorption and release characteristics, and the thickness of the wood Even if the node K is pressed toward the inside of the wood by the heat compression force from both sides in the direction, the movement of the node K is not restricted by the soft deformation of the wood structure around the node K. That is, it is difficult for the movement of the node K to be restrained. Therefore, the stress with respect to the heating compression force generated in the node K is small, and the generation of internal stress is small.
In particular, the structure of the node K tends to decrease in size from the front side of the wood to the back side of the wood, so that even if the node K is pressed from the front and back sides of the wood toward the inside, the large size of the tree Changes in the texture of the node K on the front side can be absorbed by deformation, movement, and movement of the node K by softening deformation of the wood structure around the node K tissue on the back side of the small tree. For this reason, even if a compressive force is applied, the stress generated in the node K is small, and the node K is not damaged.

In this way, even when the node K is present, excessive compression stress is not applied to the node K and the surrounding fibers inside the wood, and the generation and concentration of internal stress due to the heat compression force is small, so that the node Inclination, buckling, crushing, destruction, and the like of the portion K and the surrounding fibers are unlikely to occur, and cracks in the wood (cracks, cracks) are unlikely to occur.

In addition, since it is difficult for excessive stress to enter the entire node K in this way, a large amount of spear is prevented from being deposited from the node K. Therefore, even if there is a node K, a hot press plate used for heat compression There is no situation where the lumber is bonded to the wood and the wood is not peeled off from the hot press plate after the consolidation process. Further, since the entire node K is not compressed, there is no possibility that a large amount of spider will be deposited from the node K when the ambient environmental conditions change after the product is manufactured, thereby reducing the commercial value. In addition, since the entire node K is not highly compressed, significant darkening and blackening of the node K and its surroundings are suppressed, and a good appearance can be maintained.

And the plastically processed wood PW of the present embodiment changes the compressibility and density in the direction perpendicular to the length direction of the wood grain, that is, the thickness direction of the wood, but the width direction of the wood, In other words, since the compression rate does not change extremely in the direction perpendicular to the length direction of the wood grain, there is no difference in the expansion and contraction rate due to changes in the surrounding environmental conditions in the width direction of the wood. Dimensional shape change hardly occurs. In addition, since there is no extreme change in the compressibility and density in the width direction of the wood, the quality of wood properties such as strength is stable. In addition, since no operation corresponding to the position, dimension and shape of the node K is required, the productivity is excellent.

Here, the present inventors conducted an experimental study using soft wood having an air-dry specific gravity of 0.48 or less, for example, wood such as cedar, straw, yellow poplar, and the like. In the case of plastic working with the compression ratio of the surface layer part F being less than 45% (calculated from the air dry density corresponding to the size and shape of the final product), the increase in surface hardness relative to the original wood is low and scratched The strength characteristics that could withstand practical use could not be obtained without eliminating the ease. On the other hand, in the case of plastic working in which the compression ratio of the surface layer portion F (calculated from the air dry density corresponding to the size and shape of the final product) exceeds 65%, the surface layer portion is required to be heated and compressed with a high compression force. Since not only F but also the inner layer part I and the back layer part R have a high compressibility and the whole thickness is highly compressed, the stress applied to the inside of the wood is high and the node K is present in the wood. The breakage or the like occurs in the node K and the surrounding fibers, and the node K cracks (cracks, cracks) and wood cracks occur.

Further, in the plastic working in which the compression ratio of the inner layer portion I (calculation from the air dry density corresponding to the size and shape of the final product) is less than 10%, heat compression with a low compression force is required. With a low compressive force, a high surface hardness that could withstand practical use could not be obtained. On the other hand, in the plastic working such that the compression ratio of the inner layer portion I (calculation from the air dry density corresponding to the size and shape of the final product) exceeds 30%, stress due to heat compression tends to enter the whole wood, The stress on the inside of the timber is high, and depending on the difference in the lumber such as grain or memorial material, if there is a node K with a high occupancy rate of 10% to 20%, Fibers were easily crushed, buckled, broken, etc., and the frequency of cracks (cracks) and wood cracks at the node K increased.

Furthermore, in the plastic processing in which the compression ratio of the back layer portion R (calculated from the air dry density corresponding to the size and shape of the final product) is less than 15%, the difference in expansion and contraction rate due to changes in ambient environmental conditions on the front and back of the wood As the height of the wood increases, the balance between the front and back surfaces of the wood is poor, and stress is likely to occur inside the wood due to changes in the surrounding environmental conditions, and the stress may cause cracks in the node K. Even when there is no node K, distortion is likely to occur due to changes in ambient environmental conditions, dimensional stability is impaired, and mechanical strength is reduced. On the other hand, in the plastic working such that the compression ratio of the back layer portion R (calculation from the air dry density corresponding to the size and shape of the final product) exceeds 40%, the compression ratio by heating approaches the compression ratio of the surface layer portion F. In the processing, the internal stress is easily concentrated, and the stress applied to the inside of the wood is increased. For this reason, if the node K is present inside the wood, excessive stress is applied to the node K, and the node K and surrounding fibers are easily crushed, buckled, broken, etc. Cracks (cracks, cracks) and wood cracks are likely to occur.

That is, in order to achieve plastic processing without cracks (cracks, cracks) even when the node K is present in the wood, it is very important to control the amount of compression and density of the wood. The compression ratio within the range of 45% to 65% with respect to the air dry density of the original wood, and the back layer portion R is compressed within the range of 15% to 40% with respect to the air dry density of the original wood. According to plastic working, the inner layer part I is compressed by heating and compressing it to a compression ratio in the range of 10% to 30% with respect to the air-dry density of the original wood. Regardless of the difference in strength, even if the node K is present at a high occupancy rate of 10% to 20% in the wood, strength characteristics that can withstand practical use can be obtained, and cracks (cracks) can occur. It is difficult to occur. In the following, unless otherwise specified, the compression ratio is calculated from the air dry density corresponding to the size and shape of the final product.

In particular, when the surface layer portion F is 65% or less in terms of the compression ratio with respect to the air dry density of the original wood and the inner layer portion I is 40% or less in terms of the compression ratio with respect to the air dry density of the original wood, Regardless of the difference in lumber, the inside of the wood is made of plastic that is hard to be stressed, and the surface layer part F has a compression rate in the range of 45% to 65% with respect to the air dry density of the original wood. In the plastic working in which the layer portion R is within the range of 15% to 40% in terms of the compression ratio with respect to the air-dry density of the original wood, the difference in the compression ratio between the surface layer portion F and the back layer portion R provides The stress concentration due to the compressive force applied from the front and back sides in the thickness direction can be alleviated. For this reason, regardless of the difference in the lumber, such as the grain material or the memorial material, even if the node portion K is present at a high occupation rate of 10% to 20% in the wood, it is applied to the node portion K. There is little stress, and the node K and surrounding fibers are not crushed, buckled or broken.
Therefore, even if the node K is present in the wood, the plastic working does not cause a wood crack (crack, crack).

Further, the surface layer portion F is set to a compression rate in the range of 45% to 65% with respect to the air dry density of the original wood, and the back layer portion R is set to 15% to 40% with respect to the air dry density of the original wood. %, The stress caused by the difference in expansion and contraction due to changes in ambient environmental conditions is alleviated from being concentrated in the wood. In particular, in the case of a wood grain material, a wood surface side having a large expansion / shrinkage ratio is usually used as a surface layer portion F, which is used as a high-density plastic working, while a back layer portion R on the wood back side having a small expansion / shrinkage rate is formed from the surface layer portion F. Because of the low compression rate plastic processing, the difference between the expansion and contraction ratios of the original wood front and back is calibrated, and the balance between the front and back is improved. Therefore, even when the ambient environment conditions change, stress due to the difference in expansion / contraction rate hardly occurs. Therefore, even when the node K is present at a high occupancy rate of 10% to 20% on the wood, the stress due to the difference in contraction and expansion rate when the ambient environmental conditions change causes the node K and its surroundings. No cracks occur. In addition, since the balance between the front and back sides is excellent, there is little occurrence of distortion when the ambient environmental conditions change, the dimensional shape stability is high, and the mechanical strength is also stable.

Further, in this way, the surface layer portion F has a compression ratio in the range of 45% to 65% with respect to the air dry density of the original wood, and the back layer portion R has a compression ratio with respect to the air dry density of the original wood of 15%. In plastic working with a compression ratio in the range of 40% to 40%, it is possible to suppress the length of the wood from being compressed due to the compression in the width direction of the wood, that is, the direction perpendicular to the length direction of the grain. It is possible to reduce the specific gravity difference due to the difference in lumber such as eye material and memorial material. That is, in the case of wood grain and memorial material with different wood grain and annual ring patterns, due to the difference in compressive stress and compressive strength when compressive force in the direction perpendicular to the grain length direction is applied, the width direction of the wood If the compressibility of the surface layer portion F and the back layer portion R is within the above range, the difference in elongation deformation in the width direction of the wood can be obtained even when the node portion K exists. The specific gravity difference can be reduced. Therefore, a stable quality can be obtained regardless of the difference in the wood grain and the grain of the grain material or the memorial material.

When the surface layer portion F is 45% or more in terms of the compression ratio with respect to the air dry density of the original wood and the inner layer portion I is 10% or more in terms of the compression ratio with respect to the air dry density of the original wood, the surface side is consolidated to a hardness that can be practically used. As a result, the ease of scratching the surface of the original wood is eliminated. In particular, when the surface layer portion F is 50% or more in terms of the compression ratio with respect to the air-dry density of the original wood, even if it is used as a flooring or the like that requires high hardness, wear resistance, and impact resistance, it depends on concentrated load or impact load. Scars and dents are difficult to be attached and the material strength is increased.

In addition, the compression rate here measures the air dry density of each layer of the surface layer part F, the inner layer part I, and the back layer part R corresponding to the dimension shape of the final product, and the air dry density of the original wood, This shows how much the air dry density of each of the surface layer portion F, the inner layer portion I, and the back layer portion R has changed (increase in change) as a compression rate.
Here, as shown in FIG. 1 to FIG. 5, in the plastically processed wood PW of the present embodiment, from the apparent density difference due to the difference in compression rate, the surface layer portion F of the dark color region in the thickness direction of the wood, An inner layer portion I of a light color region and a back layer portion R of a dark color region are formed in order. The surface layer portion F of the dark color region, the inner layer portion I of the light color region, and the back layer portion R of the dark color region Can be distinguished by shades of color on the surface.
Therefore, each layer of the surface layer portion F, the inner layer portion I, and the back layer portion R is cut out in a direction parallel to the fiber direction of the wood grain (perpendicular direction to the end face), and the air dry density for each layer is measured. Thus, the compression rate for each layer can be obtained from the following equation (A).
Compression rate <%>
= [1-[(Air-dry density of original wood) / (Air-dry density of surface layer portion F, inner layer portion I, back layer portion R of plastic processed wood PW)]] × 100 (A)

When the plastically processed wood PW of the present embodiment is, for example, cedar, the air-dry density of the cedar as the original wood is 380 <kg / m ³ > on average, so The air dry density of the surface layer part F, which is a compressibility within the range of 45% to 65% in terms of the compressibility with respect to the dry density, is within the range of about 690 to 1090 kg / m ³ , and the air drying of the original wood by heat compression The air dry density of the back layer portion R, which is a compressibility within the range of 15% to 40% in terms of the density relative to the density, is within the range of about 440 to 600 kg / m ³ , and the air drying of the original wood by heat compression. The air dry density of the inner layer portion I, which is a compression rate in the range of 10% to 30% in terms of the compression rate with respect to the density, is in the range of about 420 to 550 kg / m ³ .

It should be noted that the compression ratio of the surface layer portion F in the range of 45% to 65% in terms of the compression ratio with respect to the air dry density of the original wood, and the range of 15% to 40% in terms of the compression ratio with respect to the air dry density of the original wood. The compression ratio of the inner layer portion I, which is within the range of 10% to 30% in terms of the compression ratio of the back layer portion I and the air dry density of the original wood, is based on the air dry density corresponding to the size and shape of the final product. It is calculated. That is, in order to ensure smoothness of the final product and from the necessary thickness suitable for the purpose of use, the surface of the wood is usually cut after the consolidation process. The compression ratio is expressed by measuring the air-dry density corresponding to the size and shape of the final product after cutting by about 4 mm. The compression rate at this time is obtained by cutting out each layer in a plane and calculating the compression rate from the air-dry density of the entire specific layer. From the density distribution, that is, cutting out a specific part of the specific layer. Measurements may not always fall within the above range. Moreover, even if there is an error due to measurement or the like with natural objects, it is not impossible to carry out and does not deny the intervention of the error.

In the consolidation process of the present embodiment, as will be described later, for example, when a heat compression force is applied in the thickness direction of the wood using a pair of hot plate presses (upper press board 10A and lower press board 10B), The pressure density increases toward the front and back surfaces of the wood in contact with the plate press, and the pressure density gradually decreases from the front and back surfaces toward the inside of the wood. Here, when paying attention to the annual ring line RL of the wood, the inclination angle α of the annual ring line RL with respect to the material surface (grain surface) on the back side of the wood compared to the front side of the wood (the boundary line B in FIG. 6 and FIG. 7). The acute angle side crossing angle α) formed by the annual ring line RL on the end of the end tends to be large. When the inclination angle α of the annual ring line RL with respect to the material surface (plate surface) is large, compression deformation hardly occurs. Thus, as will be described later, the lower press board 10B facing the wood back side of the wood is fixed and the upper press board 10A opposed to the wood front side of the wood is heated and compressed. As a result, the front and back sides of the wood contacting the hot plate press are most highly compressed, but the compression deformation from the front and back sides toward the inside of the wood is more easily compressed and deformed on the front side than the back side. The compression amount increases, the pressure density increases, and the thickness consolidated by the surface layer portion F is larger than the back layer portion B. Since there is a difference in compression between the front and back, the concentration of stress inside the wood with respect to the heating compression force applied in the thickness direction of the wood is also alleviated.

For this reason, when viewed before cutting, that is, the air-dry density distribution of the surface layer portion F after the consolidation including the cutting allowance when finally commercialized is about 600 to 1100 kg / m ³ . The compression ratio is within the range of about 45 to 65% within the range of about 700 to 1100 kg / m ^{3 based on} the overall air dry density of the surface layer portion F after the compaction processing. The air dry density distribution is in the range of about 500 to 1100 kg / m ³ , and the compressibility is about 45 to 65 in the range of about 600 to 1100 kg / m ^{3 based on} the overall air dry density of the back layer R. %, But the front and back surfaces with the highest pressure density are cut, for example, by cutting the front side of the wood side by about 1 mm and the back side of the back side by about 2 mm, from the front and back sides toward the inside of the wood. The compression deformation of the surface layer part F on the wood surface side is more compacted than the back layer part B on the wood side In the measurement of the air dry density corresponding to the size and shape of the final product, the surface layer part F is compressed with respect to the air dry density of the original wood. The compression ratio falls within the range of 45% to 65%, and the back layer R on the side opposite to the surface layer F is compressed within the range of 15% to 40% with respect to the air dry density of the original wood. The inner layer portion I interposed between the surface layer portion F and the back layer portion R has a compression rate within the range of 10% to 30% in terms of the compression rate with respect to the air dry density of the original wood.

The width direction of the wood depends on the width and strength of the annual ring depending on the type of wood, the running direction of the annual ring line RL, and the extension in the direction perpendicular to the direction of heat compression when a heat compression force is applied in the thickness direction of the wood. Although there may be a difference in pressure density between the central part side and the end part side, the compression ratio calculated from the air dry density corresponding to the dimensional shape of the final product is the surface layer part F, inner layer part I, back layer part R. It was calculated from the air-dry density measured by cutting out the whole.

In particular, according to an experimental study by the present inventors, the plastically processed wood PW of the present embodiment has an air dry density of the inner layer portion I of 0.35 to 0.65 times the air dry density of the surface layer portion F. And the air dry density of the back layer portion R is preferably in the range of 0.6 to 0.8 times. If the air-dry density of each layer is within the above range due to heat compression, the expansion / shrinkage ratio is well balanced, and stress is less likely to occur inside the wood even when the ambient environmental conditions change. For this reason, even if the node K is present at a high occupancy rate of 10% to 20% in the wood, the node inside the wood due to the stress due to the difference in contraction and expansion rate when the ambient environmental conditions change No cracks (cracks, cracks) occur around K and its surroundings. In addition, even if the ambient environment conditions change, the overall distortion is small, the dimensional shape stability is high, and stable high quality can be ensured.

Further, according to the experimental study by the present inventors, the ratio of the thickness of the inner layer portion I to the surface layer portion F is preferably in the range of 2 to 5 times the thickness of the inner layer portion I with respect to the thickness of the surface layer portion F. If the ratio of the thickness of the surface layer portion F and the inner layer portion I is within the above range due to heat compression, stress is hardly applied to the inside (up to the back) of the inner layer portion I. Furthermore, the compression ratio of the back layer portion R can be appropriately increased to ensure the balance with the surface layer portion F, that is, the dimensional shape stability. The ratio of the thickness of the back layer portion R to the surface layer portion F is preferably in the range of 0.5 to 1 times the thickness of the back layer portion R with respect to the thickness of the surface layer portion F. If the ratio of the thickness of the surface layer portion F and the back layer portion R is within the above range, the concentration of internal stress inside the wood can be relaxed.
Therefore, in the measurement on the surface of the wood surface side or the memorial surface, for example, even when a large node K having a diameter of 1 cm or more exists through in the thickness direction, the occupation ratio of the node K is 10% to Even 20%, the compressive stress applied to the node K is small, the fibers of the node K are hardly buckled, crushed, broken, etc., and the plastic working is difficult to cause wood cracks (cracks). Further, even when the node portion K penetrates in the thickness direction, significant darkening and blackening of the node portion K and its surroundings due to compression can be suppressed, and the surface design can be maintained. Furthermore, the thickness and compression ratio of the front and back sides are well balanced, and high dimensional shape stability can be ensured even if the ambient environmental conditions change.

The overall compression rate of the plastically processed wood PW of the present embodiment is the compression rate relative to the thickness of the original wood (the wood NW before processing), that is, based on the overall thickness of the original wood. The compression ratio converted from the total thickness of the plastically processed wood PW is in the range of 20% to 50%, preferably in the range of 25% to 45%. According to the experimental study by the present inventors, if the compressibility with respect to the entire thickness is too low, a sufficiently high compressibility and strength cannot be obtained in the surface layer portion F. On the other hand, if the compressibility is too high, the inside of the wood is applied. When the stress increases and the node K is present, cracks are likely to occur at the node K and its surroundings. If the compression ratio with respect to the thickness of the original wood is within the range of 20% to 50%, preferably within the range of 25% to 45%, the surface hardness can be obtained without cracking even if the node K is present. In addition, darkening and blackening of the knot K are suppressed, and the appearance is good.

For example, the total thickness of the plastic-processed wood PW of the present embodiment is set to a necessary thickness commensurate with the purpose of use, but preferably 20 mm including the cutting allowance when finally commercialized. Within the range of ˜50 mm, more preferably within the range of 20 mm to 40 mm. According to the experimental study by the present inventors, when the overall thickness is too thin, when trying to control each layer with a predetermined compression rate, the joint portion K becomes a plastic working that can increase the compression rate of the entire thickness. If present, the frequency of occurrence of cracks (cracks, cracks) increases. In addition, when the plastic processing is performed on thin wood, the compression allowance is reduced, so that it is difficult to obtain the strength and hardness necessary for the surface layer portion F. On the other hand, plastic-processed wood PW having an overall thickness that is too thick is processing of thick wood NW, so that the moisture content inside the wood can be sufficiently reduced to the extent that dry cracking does not occur in the drying treatment before heat compression. It becomes difficult, and the inside of the wood is easily compressed and stress is easily applied. For this reason, if there is a node K, the frequency of occurrence of cracks (cracks, cracks) increases. Therefore, if the total thickness of the plastically processed wood PW is preferably within a range of 20 mm to 50 mm, more preferably within a range of 20 mm to 35 mm, it can be controlled to a predetermined compression rate in the thickness direction of the wood and practically used. It is possible to ensure a sufficient strength, and even if there is a node K, the plastic working is difficult to generate cracks, and a high yield can be secured.
Even if the cutting allowance (for example, usually 1 to 4 mm) at the time of final production is included, the thickness of the surface layer portion F is, for example, in the range of 2 mm to 7 mm, preferably 2 mm to 5 mm. The thickness of the inner layer portion I is in the range of 10 mm to 45 mm, preferably in the range of 15 mm to 30 mm, and the thickness of the back layer portion R is in the range of 2 mm to 6 mm, preferably 2 mm. Within the range of ~ 5 mm.

Here, by applying heat compression in the direction perpendicular to the length direction of the wood grain in this way, the compression ratio with respect to the air-dry density of the original wood (the unprocessed wood NW) is 45% to 65% by heat compression. The compression ratio for the air-dry density of the original wood (wood NW before processing) by heat compression on the surface layer portion F in the high-density plastic working region within the range of, and on the surface opposite to the surface layer portion F is 15% to 40% In the range, the lower layer portion R of the medium density plastic working region having a lower compressibility than the surface layer portion F, and the original wood (the unprocessed wood NW) interposed between the surface layer portion F and the back layer portion R by heat compression ) In which the compression ratio with respect to the air-dry density is in the range of 10% to 30%, and the inner layer portion I of the low-density plastic working region having a lower compression ratio than the surface layer portion F and the back layer portion R. Then, as shown in FIG. 1 to FIG. 5 and the like, the color tone appearing on the mouth end changes characteristically. Further, the strike direction of the annual ring line RL appearing on the face of the mouth is the boundary between the surface layer portion F of the high-density plastic working region and the inner layer portion I of the low-density plastic working region, and the inner layer portion I of the low-density plastic working region. It changes characteristically at the back layer R and the boundary in the medium density plastic working region.

That is, it is a plastic working in which the compressibility is changed in the direction perpendicular to the length direction of the wood grain, so that the compressibility relative to the air-dry density of the original wood by heating compression is within a range of 45% to 65%. The surface layer portion F in the high-density plastic working region with a compression ratio of 5 and the surface layer in the range of 15% to 40% in terms of the compression ratio with respect to the air-dry density of the original wood by heat compression on the surface opposite to the surface layer portion F The back layer portion R of the medium density plastic working region, which has a compression rate lower than that of the portion F, is dark in color tone, whereas the compression rate with respect to the air dry density of the original wood by heat compression is 10% to 30%. The inner layer portion I in the low density plastic working region having a lower compressibility than the surface layer portion F and the back layer portion R within the range is lighter than the surface layer portion F and the back layer portion R.

Furthermore, the plasticity is such that the compression ratio is changed to a predetermined compression ratio by changing the compression ratio in a direction perpendicular to the length direction of the wood grain, so that the compression ratio relative to the air dry density of the original wood is 45%. The surface layer portion F in the high-density dark color region with a compression rate in the range of ~ 65%, and the compression rate lower than that of the surface layer portion F in the range of 10% to 30% with respect to the air-dry density of the original wood On the boundary line BL ₁ appearing on the front edge of the inner layer part I of the low-density light-colored region located on one side (lower side) of the surface layer part F in the thickness direction of the wood, the bending point (transition) of the annual ring line RL point) f ₁ is present. Furthermore, the inner layer portion I of the low density light-colored region having a compression ratio lower than that of the back layer portion R within the range of 10% to 30% compression ratio with respect to the air-dry density of the original wood, and the original wood by heat compression A back layer portion R of a medium density dark color region located on one side (lower side) of the inner layer portion I on the opposite surface side to the surface layer portion F within a compression ratio with respect to the air dry density of 15% to 40%; even on the boundary line BL ₂ appearing in butt surfaces of the bending point of the annual ring lines RL (transition point) f ₂ is present.

That is, in the direction perpendicular to the length direction of the wood grain, differences and changes in the compression amount, density, and plastic working characteristics appear on the end face as bending points f ₁ and f ₂ of the annual ring line RL. The surface has a point f ₁ where the annual ring line RL is bent (bending point) f ₁ on the boundary line BL ₁ between the surface layer portion F of the dark color region and the inner layer portion I of the light color region, and the inner layer portion of the light color region On the boundary line BL ₂ between I and the back layer portion R of the dark region, there is a point (bending point) f ₂ where the annual ring line RL is bent.

In particular, the compression ratio of the surface layer portion F is the largest compression ratio in the range of 45% to 65% with respect to the air dry density of the original wood, and the compression ratio of the inner layer portion I is the air dry density of the original wood. The compression ratio with respect to is the smallest compression ratio within the range of 15% to 40%, and the compression ratio of the back layer portion R is within the range of 10% to 30% with respect to the air dry density of the original wood. The difference in compression rate between the surface layer portion F and the inner layer portion I is larger than the difference in compression rate between the back layer portion R and the inner layer portion I. The bending degree at the bending point f ₁ of the annual ring line RL above ₁ is greater than the bending degree f _{2 at} the bending point of the annual ring line RL above the boundary line BL ₂ between the back layer portion R and the inner layer portion I. The annual ring line RL to be inclined has a gentler slope than the annual ring line RL running to the back layer portion R.
Here, the degree of bending at the bending point f ₁ means that when a straight imaginary line I ₁ extending from the bending point f ₁ to the surface layer part F is extended to the surface layer part F from the bending point f _1, The inclination angle θ ₁ of the annual ring line RL of the surface layer portion F with respect to the virtual line I ₁ . Also, the tortuosity and the bending point f _2, in butt surfaces, when drawn an imaginary line I ₂ straight extending from the bending point f ₂ toward the annual ring line RL of the inner layer I to the back layer unit R1 that This is the inclination angle θ ₂ of the annual ring line RL of the back layer R with respect to the imaginary line I ₂ . Then, the bending of the bending point f ₁ is greater and also the bent degree of the bending point f _2, which means that the θ _1> θ _2. (See Fig. 1 and Fig. 2)

That is, in the plastic working in which the density is changed by changing the compression rate in the direction perpendicular to the length direction of the grain, the predetermined compression rate, the difference or change in density is as the shade of the color of the wood, Appears as bending of the annual ring line RL on the end of the tree. In particular, the difference in compressibility of each layer due to plastic working also appears in the annual ring width composed of the early and late material parts, and the difference in annual ring width is manifested as a bend in the annual ring line RL on the end of the head. The points f ₁ and f ₂ exist on the boundary line BL ₁ between the surface layer portion F and the inner layer portion I and on the boundary line BL ₂ between the inner layer portion I and the back layer portion R. The difference in the compression ratio between the surface layer portion F and the back layer portion R with respect to the inner layer portion I is the difference in bending degree between the bending points f ₁ and f ₂ .

Therefore, the plastically processed wood PW of the present embodiment has a higher compressibility than the inner layer portion I in which the surface layer portion F and the back layer portion R on the opposite surface side are interposed between the surface layer portion F and the back layer portion R. Bending points f ₁ , f _{2 of the} annual ring line RL at a boundary between the surface layer portion F and the inner layer portion I and a boundary between the inner layer portion I and the back layer portion R which are darker than the inner layer portion I and appear on the end surface. And the bending degree f ₁ of the annual ring line RL on the boundary between the surface layer part F and the inner layer part I is equal to the bending point f ₂ of the annual ring line R on the boundary between the inner layer part I and the back layer part R. It can also be understood as an invention that is greater than the degree of bending.

In this way, the surface layer portion F and the back layer portion R on the opposite side thereof have a higher compressibility than the inner layer portion I interposed between the surface layer portion F and the back layer portion R, so that they are thicker than the inner layer portion I. In addition, the bending line f ₁ of the annual ring line R is formed on the boundary line BL ₁ between the surface layer part F and the inner layer part I and the boundary line BL ₂ between the inner layer part I and the back layer part R. has f _2, the surface layer portion F and the inner layer portion annual ring line tortuosity bending point f ₁ of annual ring line RL on the boundary line BL ₁ is on the boundary line BL ₂ of the backing layer portion R and the inner layer portion I of the I RL Also in the plastic working to make the bending point f ₂ greater than the bending degree, the density is changed by changing the compressibility in the direction perpendicular to the length direction of the wood grain, that is, in the thickness direction of the wood. Therefore, stress due to heat compression is difficult to enter. That is, even if the node K is present, the entire node K is not subjected to excessive compressive force or stress.

In particular, the surface layer portion F and the back layer portion R are darker than the inner layer portion I, and the bending degree of the bending point f ₁ of the annual ring line RL on the boundary line BL ₁ between the surface layer portion F and the inner layer portion I is the back layer portion R. The plastic working in which the bending degree f ₂ of the bending point of the annual ring line RL on the boundary line BL ₂ between the inner layer portion I and the inner layer portion I is larger than the surface layer portion F and the back layer portion R is made of wood. The inner layer portion I which is the inside of the inner layer portion is made difficult to be compressed compared to the front and back layer sides, and the compression rate of the back layer portion R is made lower than that of the front layer portion F so that the compressibility is different between the surface layer portion F and the back layer portion R. That is, the difference in the compressibility between the surface layer portion F and the inner layer portion I and the difference in the compressibility between the back layer portion R and the inner layer portion I are alleviated, thereby reducing the concentration of internal stress due to compression. This is to prevent compression stress inside the wood.
Therefore, even when the node K is present in the wood, the entire node K is prevented from being subjected to excessive compressive force and stress, and in particular, excessive stress is not applied to the fiber of the node K inside the wood. Further, buckling, crushing, destruction, etc. of the fiber of the node portion K hardly occur, and the wood does not cause cracking.

In this way, the surface layer portion F and the back layer portion R are darker than the inner layer portion I, and the bending degree of the bending point f ₁ of the annual ring line RL on the boundary line BL ₁ between the surface layer portion F and the inner layer portion I on the front end is reverse. Also in the plastic working in which the bending degree f ₂ of the bending point of the annual ring line RL on the boundary line BL ₂ between the layer part R and the inner layer part I is larger than the surface layer part F, the surface layer part F has the highest compressibility. The back layer portion R on the side is set to a compression rate lower than that of the surface layer portion F, and the inner layer portion I interposed between the surface layer portion F and the back layer portion R is set to the lowest compression rate. Therefore, the inner layer portion I has the lowest compression ratio, so that the inside of the wood is hardly compressed, and the compression ratio is different between the front and back, and the concentration of internal stress generated in the wood due to the compressive force in a specific direction. Since the stress has been relaxed, the strength characteristics are enhanced with a small amount of compressive stress entering the wood.

Further, according to actual measurement by the present inventors, the bending degree of the bending point f ₁ of the annual ring line RL on the boundary line BL ₁ between the surface layer part F and the inner layer part I is preferably within a range of ± 0 to 30 degrees.
Here, the degree of bending at the bending point f ₁ is ± 0 to 30 degrees. The straight imaginary line I that extends the annual ring line RL of the inner layer portion I from the bending point f ₁ toward the surface layer portion F from the bending point f _1. _{When 1} is subtracted, the inclination angle θ ₁ of the annual ring line RL of the surface layer portion F with respect to the virtual line I _{1 is} ± 0 to 30 degrees. Strictly speaking, the inclination θ ₁ of the annual ring line RL of the surface layer portion F is not 0 ° from the expression of bending, but since it is a natural object, θ ₁ ≈0 ° may be obtained. Therefore, the inclination angle θ ₁ is expressed as ± 0 to 30 degrees.

Increasing the compression ratio of the surface layer portion F increases the hardness and can eliminate the susceptibility to scratches on the surface. However, when the compression is high, the present inventors have a problem that cracks (cracks, cracks) easily occur in the wood or on the surface. is focused on the tortuosity bending point f ₁ appearing in end grain surface, as long as it is within the range tortuosity is predetermined, stable strength can be obtained the hardness of the surface is increased in cracks from entering, high product quality It was found that it can be secured. Then, when the degree of bending at the bending point f ₁ when the surface hardness is increased and a stable strength can be secured without cracking or the like, the bending degree at the bending point f ₁ is within a range of ± 0 to 30 degrees, that is, It was confirmed that the inclination angle θ ₁ of the annual ring line RL is preferably ± 0 to 30 degrees.
According to the actual measurement by the present inventors, when the compression angle is high and the inclination angle θ ₁ > 30 degrees, the stress is concentrated at the boundary between the surface layer portion F and the inner layer portion I, and cracks occur due to buckling deformation of the annual ring line RL. Cracks are likely to occur, but cracks and the like are caused by setting the bending angle of the bending point f ₁ within the range of ± 0 to 30 degrees, that is, by setting the inclination angle θ ₁ of the annual ring line RL to ± 0 to 30 degrees. The surface becomes difficult to be scratched, stable strength is obtained, and high product quality can be secured.

It should be noted that the above-described magnitude of the degree of bending and the degree of bending are ideally applicable to all annual ring lines RL appearing on the face of the wood with no knot K. In addition, it is intended for natural objects, and in the wood with the node K, the annual ring line RL is disturbed around the node K, so practically all the annual ring lines RL appearing on the end of the tree On the other hand, it does not strictly require that the degree of bending and the specific bending angle are satisfied, and there are several percent of annual ring lines RL that do not satisfy such a condition on the end surface. There is virtually no problem.

Here, as shown in FIGS. 1 to 5 and the like, the plastically processed wood PW according to the present embodiment has a high density in the direction perpendicular to the length direction of the grain, that is, in the thickness direction of the wood. In this structure, a surface layer portion F that is a plastic working region, an inner layer portion I that is a low density plastic working region, and a back layer portion R that is a medium density plastic working region are formed in succession.
And, due to the obvious density difference due to the difference in compression ratio, the surface layer portion F and the back layer portion R are dark regions, while the inner layer portion I between them is a light color region, the three layers are distinguished Although the density distribution in the thickness direction of the wood is seen, the density is not uniform in each layer of the surface layer portion F, the inner layer portion I, and the back layer portion R, and from the front surface side of the surface layer portion F and the back surface side of the back layer portion R. It gradually changes from a high density state to a low state toward the inside. According to the experimental study by the present inventors, for example, in the plastically processed wood PW having a thickness of 25 mm, the density is gradually decreased from the surface of the surface layer portion F to a depth of about 10 to 18 mm, and at the depths thereafter. It has been confirmed that the density gradually increases as it approaches the back surface of the back layer portion R. In cedar, etc., there is an early wood part that constitutes the annual ring line and a late wood part that constitutes the annual ring line, and there is a density difference between the early wood part and the late wood part. Although the density gradually changes from a high density state toward a low density state from the front surface side of the surface layer portion F and the back surface side of the back layer portion R, strictly speaking, the change in density between them is not necessarily linear. Instead of descending from a high value to a low value, it moves up and down.

Therefore, in the plastic working in which the density gradually changes from a high density state to a low state from the front surface side of the surface layer portion F and the back surface side of the back layer portion R to the inside in this way, the difference in expansion and contraction rate at the boundary of each layer Are not significantly different from each other, so there is no large internal stress due to the difference in expansion and contraction due to changes in the surrounding environmental conditions, and cracks in the node K (cracks) due to changes in the surrounding environmental conditions. Is less likely to occur, and overall distortion is less likely to occur.

Here, an example of a method for producing the plastically processed wood PW of the present embodiment having such a configuration will be described mainly with reference to FIGS. 6 to 9.

First, the unprocessed woods NW1, NW2, NW3, and NW4 that are the raw materials of the plastically processed woods PW1, PW2, PW3, and PW4 of the present embodiment as shown in FIGS. Lumbered. The thickness, width, and length of the unprocessed wood NW1, NW2, NW3, and NW4 vary depending on the use and purpose of the plastically processed wood PW1, PW2, PW3, and PW4 obtained by compacting the wood. Sawwood is used as square or rectangular square. The plastically processed woods PW1, PW3, and PW4 shown in FIGS. 1, 4, and 5 are examples of plastic working of the unprocessed woods NW1, NW3, and NW4 that are produced as plate materials. The plastically processed wood PW2 indicated by 3 is an example of plastic processing of the unprocessed wood NW2 that has been produced as a memorial material.

Here, in order to prevent cracking due to heat compression, as the unprocessed wood NW, the boundary line B where the butt face and the wood back side board surface (tree side board surface) or the memorial surface cross at a right angle It is preferable to use a grain material or a memorial material in which the acute angle crossing angle α (annual ring angle α) formed by the annual ring line RL on the end face is within a range of 60 degrees or less (see FIGS. 6 and 7). If the crossing angle α on the acute angle side formed by the boundary line B and the annual ring line RL on the mouth end surface is 60 degrees or less, the early material portion is not easily cracked due to buckling deformation of the annual ring by heat compression. In particular, even if there is a node K and the annual ring line RL is disturbed around the node K, if the annual ring angle α of the other part is 60 degrees or less, the node K and the surrounding area are cracked. It is possible to perform heat compression without causing any problems.

This pre-processed wood NW does not ask for sapwood (white / white) or heartwood (red), but generally coniferous trees such as cedar have a larger amount of yabi, compared to heartwood. In the material portion, since the amount of exposure by heat compression is small, it can be suitably used as the amount of sapwood is large. Further, since the sapwood has a brighter color than the core material, the dark color change when consolidated is suppressed more than the core material, and a good appearance is maintained.
Wood NW before processing uses damaged wood, scraps, etc. that are no longer usable in the state of logs due to falling or core cracks due to natural disasters such as thinning, wind damage, water damage, snow damage, forest fire, frost damage, insect damage, etc. May be. As a result, the cost can be reduced and the environment can be beautified.

The unprocessed wood NW that has been lumbered to a predetermined thickness of wood is dried so as to have a moisture content below the fiber saturation point before performing the predetermined compaction processing using the plastically processed wood device 100 shown in FIGS. Is done. Moisture content below the fiber saturation point, preferably by drying once so that the moisture content is below the air-dried state, to give strength on the inner side of the wood, and more sufficient than later heat compression on the surface side of the wood Can cause chemical changes. The moisture content of wood is a ratio of moisture weight to wood weight not containing moisture (total dry weight, dry base), and can be measured using a measuring instrument such as a high-frequency moisture meter. In general, moisture content evaporates from the surface side of the wood, so the moisture content of the wood decreases as it gets closer to the surface, but the moisture content here is a value measured as the moisture content of the whole wood. .

At this time, the lower the moisture content, the more the compression can be concentrated on the front and back sides of the wood to increase the compression rate. However, if the moisture content of the wood is made lower than necessary, the strength is lost due to shrinkage of the wood. Cracks occur during the drying process. In addition, when the node K is present in the wood, the moisture absorption and release characteristics of the water around the node K and its surroundings are high, and the moisture easily evaporates, so that the node K and its surroundings are cracked during the drying process. Cracks are likely to occur.

Therefore, according to an experimental study by the present inventors, in the case of a conifer such as cedar, the wood NW before processing is dried so that the entire moisture content is within a range of 5% to 15%, and the dry wood DW is obtained. It is preferable to do this. More preferably, the moisture content is in the range of 8% to 10%.
If the moisture content measured as the moisture content of the whole wood is preferably 15% or less, more preferably 10% or less, the moisture content on the inner side of the wood will be very low, and the inner side of the wood will have high fiber strength. It becomes difficult to be compressed. As a result, the compression by the subsequent heat compression is concentrated on the front and back surfaces of the wood to which moisture is added later, and it is difficult to apply compression stress to the inside of the wood. Therefore, even when the node K is present, it is difficult to apply a compressive stress to the interior of the wood by subsequent heat compression, so that an excessive compressive force is not applied to the node K, so that the fibers of the node K are buckled. It is difficult for destruction to occur. In addition, even when the moisture content in the wood is extremely low as described above, when the node K is present, the tissue becomes moderately soft around the node K due to the high moisture absorption property of the node K during the subsequent heat compression. Therefore, even when the node K receives an external force, the tissue can be deformed following the movement of the node K, and no great stress or stress is applied to the node K or its surroundings. And if the moisture content measured as the moisture content of the whole wood is preferably 5% or more, more preferably 8% or more, it is possible to ensure a strength that is difficult to be compressed inside the wood, even when the node K is present. In this state, no breakthrough occurs and the subsequent dimensional change hardly occurs.

Drying to make the wood NW before processing have a desired moisture content is performed by a known drying device, for example, an artificial dryer D (FIG. 6B or FIG. ))) And the like. At this time, the total moisture content of the unprocessed wood NW is measured in advance, and the moisture content, the tree type of the unprocessed wood NW, the thickness thereof, and the like are used as parameters, and the artificial dryer is set to have a predetermined moisture content after drying. Drying conditions in a drying apparatus such as D, ie, predetermined temperature, humidity, drying time (in the case of cedar, for example, the drying temperature is about 40 to 100 ° C., the temperature difference between the wet and dry bulbs is about 1 to 30 ° C. The period is about 3 to 10 days). In general, the drying temperature is gradually increased and the humidity is gradually decreased during the drying period.

In addition, the means for drying the unprocessed wood NW to a predetermined moisture content is not limited to artificial drying, and may be combined with natural drying. In the above description, the wood cut from the log and the log is sawn to a predetermined size and then dried. However, when the present invention is carried out, the wood cut from the log and the log is dried to a predetermined moisture content. Then, the lumber may be sawn to a predetermined size.

Subsequently, in the present embodiment, in order to easily heat and compress the front and back sides in the thickness direction of the wood, the dry wood DW formed by drying the unprocessed wood NW so as to have a predetermined moisture content. Moisture is added to the surface side, that is, humidification is performed.
For example, as shown in FIG. 6 (c) and FIG. 7 (c), by immersing the entire dry wood DW in the water W in the water tank 5 in which the water W is stretched, Moisture addition can be performed. In addition, when immersing the dry wood DW in the water W in the water tank 5 for immersing the dry wood DW, the dry wood DW is put in a frame or a wire mesh container so that the dry wood DW does not float by buoyancy. Therefore, a stopper, a lid, and the like are provided on the upper surface side of the dry wood DW.

The moisture addition at this time is, for example, an immersion time of about 30 seconds to 60 seconds, and even if moisture permeates from the surface side toward the inside, the entire moisture content is compared with the dry wood DW whose moisture content is adjusted. Is performed to such an extent that it can be suppressed to an increase of 3% or less. That is, in general, the moisture penetration is higher from the wood mouth side of the wood where the passageway of the conduit is located than in the direction of the wood grain or the direction of the wood, where moisture addition is Regardless of the eye direction of the wood, the entire surface of the wood is wet and humidified, and even if it penetrates into the wood, the depth is within 1 mm, and the whole wood is heated and compressed by immersion in water. Even if moisture is added to the surface other than the surface (the front and back surfaces in the thickness direction of the wood), there is substantially no problem with compression to a predetermined compression ratio if the depth is within 1 mm.

In the case of carrying out the present invention, it is sufficient that the compression deformation in the wood can be suppressed and the compression can be concentrated on the front and back sides of the wood by subsequent heat compression, so that moisture is added to the entire surface of the dry wood DW. Even if not, only the surface to be heated and compressed may be selectively added. That is, it suffices if moisture can be added to the front and back surfaces of the dry wood DW in the thickness direction of the wood, which is the surface to be heated and compressed. The means for adding moisture to the surface side of the dry wood is not limited to immersing the wood in water, and water may be sprayed or sprayed on a specific surface, or water may be applied with a brush or the like. Also good.

And if it is dry wood DW with a predetermined moisture content, moisture is immediately added to the surface side of the dry wood just by immersing it in water for a short time, especially when the whole is immersed in water. However, when immersed for a short period of time, there is almost no difference in permeability in the direction of the wood (the face of the mouth, the face of the board, or the face of the face), and the subsequent heat compression due to the decrease in the strength of the material due to the addition of moisture on the surface side. Thus, the effect that the surface side is easily heated and compressed can be obtained.

Next, the surface hydrous wood WW formed by adding moisture to the surface side of the dry wood DW in this way is subjected to compaction processing by heat compression and compression fixation.
Here, as shown in FIGS. 8 and 9, the plastically processed wood manufacturing apparatus 100 that performs consolidation processing on the surface water-containing wood WW is mainly divided into two structures of an upper press board 10A and a lower press board 10B. The press board 10 that forms the internal space IS by the body and the peripheral part 10a of the upper press board 10A that opposes the peripheral part 10b of the lower press board 10B are arranged within the predetermined vertical movement range of the upper press board 10A. A seal member 11 that seals the space IS, a pipe 12 that communicates with the internal space IS from the upper surface side of the upper press panel 10A and has a pipe port 12a for supplying steam into the internal space IS, and upstream thereof Side valve V4, a pipe 13 communicated into the internal space IS from the side of the lower press panel 10B, and having a pipe port 13a for discharging water vapor from the internal space IS, A pressure gauge P2 for detecting the atmospheric pressure, the valve V5 on the downstream side, and a connected drain pipe 14, etc. to the valve V5.

Pipe lines

15 and 16 are formed in the upper press board 10A and the lower press board 10B of the press board 10 to raise the temperature to a desired temperature by passing high-temperature steam. , 16 are connected to pipes ST2, ST3 branched from the steam supply side pipe ST1 and steam discharge side pipes ET1, ET2, respectively. Further, in the middle of the steam supply side pipes ST1, ST2, ST3, valves V1, V2, V3 and a pressure gauge P1 for detecting the steam pressure in the pipe ST1 are arranged, and the steam discharge side pipes ET1, ET2 Is connected to the drain pipe 14 via a valve V6.

Further, on the press board 10, a cooling water supply side that cools to a desired temperature by passing low-temperature cooling water in place of water vapor through the

pipes

15 and 16 formed in the upper press board 10A and the lower press board 10B. Pipes ST12 and ST13 branched from the pipe ST11 are connected to the pipes ST2 and ST3, respectively. Further, valves V11, V12, V13 are arranged in the middle of the pipes ST11, ST12, ST13 on the cooling water supply side.

It should be noted that 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 pressurizes the upper press panel 10A by ascending / descending the lower press panel 10B on the fixed side of the press panel 10. A press lifting device including a hydraulic mechanism is omitted.
In the present embodiment, high-temperature steam is introduced to heat the upper press board 10A and the lower press board 10B of the press board 10, but when the present invention is implemented, the heating medium of the press board 10 is converted to high-temperature steam. Without being limited, oil or the like may be used, and wood may be heated by heating means such as high frequency heating, microwave heating, or a heater. In particular, for the high-frequency heating of wood, a method of heating from the center of wood at a high frequency slightly lower than that of microwave is preferable to dielectric overheating by microwave.

In the press panel 10, a planar mold having a planar size capable of pressing the entire front and back surfaces in the thickness direction of the wood is used, and the material is not particularly limited, so that the wood is not blackened due to iron ion contamination. For example, a steel material such as stainless steel or aluminum is used, or the contact surface with the surface water-containing wood WW is plated. In particular, according to the press board 10 made of stainless steel, aluminum steel or the like, or the press board 10 subjected to the plating process, the press board 10 heat compresses the surface hydrous wood WW having the node K on the front and back surfaces. Even in this case, discoloration contamination to the wood due to the resin component such as the resin eluted from the node K being attached to the press board 10 can be prevented, and the press board 10 is scratched or dented with respect to the node K. The strength is such that it is difficult to occur. Further, the material of the seal member 11 for sealing the internal space IS is not particularly limited, but usually, silicon rubber, silicon resin, etc. excellent in heat resistance and water resistance are used.

When the surface hydrous wood WW is consolidated using the plastic working wood manufacturing apparatus 100 configured as described above, first, as shown in FIG. The movable upper press board 10B is raised with respect to 10B, and the surface hydrous wood WW is placed on the fixed lower press board 10B.

Here, in the present embodiment, the direction in which the upper press board 10A and the lower press board 10B are press-compressed by the two-part press board 10 is perpendicular to the length direction of the grain of the surface hydrous wood WW. A compressive force is applied in a direction perpendicular to the surface (front and back surfaces in the thickness direction of the wood).

For example, as shown in FIG. 6 (d), when the surface hydrous wood WW is a grain material, the wood back side (the inside of the annual ring) of the grain surface perpendicular to the length direction of the grain is used. It is placed on the lower press panel 10B of the press panel 10. That is, the wood surface side of the grain surface is opposed to the lower press board 10B, and the wood surface side of the grain surface is opposed to the upper press board 10A, and is perpendicular to the length direction of the grain of the surface hydrous wood WW. The smooth side is the surface that is pressed and compressed by the press 10.
As shown in FIG. 7D, when the surface hydrous wood WW is a chamois material, the chasing surface perpendicular to the length direction of the grain is placed on the lower press disk 10B of the press board 10. The chasing surface side perpendicular to the length direction of the grain of the surface water-containing wood WW becomes the surface to be pressed and compressed by the press board 10.

In performing the heat compression process, the surface side perpendicular to the grain direction of the surface hydrous wood WW is made to face the upper press panel 10A and the lower press panel 10B of the press panel 10, and the fixed side lower press. As shown in FIG. 9B, the upper press board 10A is first lowered at a predetermined pressure (for example, 0.05 to 0.3 [MPa]) with respect to the front and back layer hydrous wood WW placed on the board 10B. Then, it is brought into contact with the upper surface of the surface water-containing wood WW, that is, the upper surface in the direction perpendicular to the length direction of the grain for a predetermined time (for example, 10 seconds to 120 seconds). At this time, the upper press panel passes water vapor at a predetermined temperature (for example, 110 to 210 [° C.], temperature increase processing time 10 to 25 [min]) through the pipe line 15 of the upper press panel 10A and the pipe path 16 of the lower press panel 10B. 10A and the lower press panel 10B are heated to a predetermined temperature (eg, 110 to 210 [° C.]).

Then, the compression pressure of the upper press board 10A is set to a predetermined pressure (for example, 2 to 5 [MPa], 20 to 50 kg / cm ² ) with respect to the lower press board 10B on the fixed side, and the upper press board 10A is lowered. The surface hydrous wood WW is heated and compressed by the upper press board 10A and the lower press board 10B (for example, treatment time 0.5 to 3 [min], compression speed 15 to 100 [mm / min]). When the upper press board 10A is lowered, the surface hydrous wood WW is heated and compressed by the upper press board 10A and the lower press board 10B, and the peripheral portion 10a of the upper press board 10A comes into contact with the peripheral portion 10b of the lower press board 10B. As shown in FIG. 9C, the internal space IS formed by the upper press board 10A and the lower press board 10B is hermetically sealed by the seal member 11 disposed on the peripheral edge portion 10a of the upper press board 10A. Become.

At this time, while the inside of the surface water-containing wood WW is in a high strength state with a low water content, a table of the surface water-containing wood WW against which the upper press board 10A and the lower press board 10B brought into a high temperature state are brought into contact. Since moisture is added to the back surface (upper surface and lower surface) and the front and back surfaces are wet, the front and back surfaces are easily compressed, and the upper press panel 10A and the lower press panel 10B are in contact with the front and back surfaces of the wood. Therefore, even if surplus moisture on the front and back sides of the wood is steamed, it penetrates into the inside without escaping from the front and back sides, and the compression ratio increases in the range in which the moisture penetrates. Therefore, the stress applied to the inner layer side can be reduced. For this reason, even if the structure | tissue of the node part K exists inside, the stress applied to the node part K can be reduced. And the area | region where the compression rate was raised at this time is made into the dark color area | region of the surface layer part F and the back layer part R by the increase in the density by a compaction process, as shown in FIG. 1 thru | or FIG. That is, it becomes the plastically processed wood PW in which the three-layer structure of the surface layer portion F, the back layer portion R on the opposite side of the surface layer portion F, and the inner layer portion I therebetween is formed by consolidation.

Here, by adjusting the moisture content of the wood, the pressure of the press board 10, the heating temperature, the heating time, the compression speed, etc., 45% to 65% on the upper layer side facing the movable upper press board 10 A and moisture is added. 15% to 40% of the compression ratio lower than the upper layer side (surface layer portion F) on the lower layer side facing the lower press disk 10B on the fixed side, the surface layer portion F that becomes a high density dark color region having a compression rate within the range Back layer portion R that becomes a medium density dark color region that is a compression rate within, and inner layer portion that is a low density light color region that is a compression rate within a range of 10% to 30% of the compression rate lower than the upper layer side and lower layer side In order to form I, an optimum value is set in advance by experiments or the like using the wood species, the moisture content of dry wood, and the like as parameters.
In particular, the inside of the surface water-containing wood WW is brought into a high strength state with a predetermined low water content by drying, and water is added to the surface side of the surface water-containing wood WW, so that the press panel 10 heated to a predetermined temperature is used. When the lower press board 10B is fixed and the upper press board 10A is moved to come into contact with the upper surface of the surface water-containing wood WW at a predetermined pressure and lowered at a predetermined compression speed, the mechanical strength such as high fiber strength on the wood inner layer side is obtained. From the characteristics, and due to the decrease in strength due to changes in the chemical properties of the wood component due to moisture and high heat on the surface side (hydrolysis of amorphous components such as hemicellulose and lignin, decrease in softening point), the upper surface side is most easily compressed, While the lower surface side is easily compressed, compression stress is hardly applied on the inside thereof, and the compression rate is lower than that on the upper layer side and the lower layer side.

In this embodiment, the vertical dimension of the internal space IS when the internal space IS formed by the upper press disk 10A and the lower press disk 10B of the press disk 10 is in a sealed state via the seal member 11. The interval is set to a finished dimension in the thickness direction when the surface hydrous wood WW becomes the plastic-processed wood PW having a predetermined compression ratio with respect to the thickness by the press board 10. Therefore, the compression ratio of the entire thickness of the surface water-containing wood WW, that is, the change in thickness (compression amount) due to the compression of the surface water-containing wood WW is determined by the peripheral edge portion 10b of the upper press board 10A and the peripheral edge part 10b of the lower press board 10B. It will be decided by contacting.

For example, when the total thickness of the lumbered unprocessed wood NW is 30 mm, the overall thickness of the plastically processed wood PW is 24 mm and 30% when the compression is 20% with respect to the overall thickness of 30 mm. When the compression rate is compressed, the total thickness of the plastically processed wood PW is 21 mm, and when the compression rate is 40%, the overall thickness of the plastically processed wood PW is 18 mm. When the total thickness of the lumbered unprocessed wood NW is 40 mm, the overall thickness of the plastically processed wood PW is 32 mm and the compression rate is 30% when the compression is 20% with respect to the total thickness of 40 mm. When compressed at, the overall thickness of the plastically processed wood PW is 28 mm, and when compressed at a compression rate of 40%, the overall thickness of the plastically processed wood PW is 24 mm. When the total thickness of the lumbered unprocessed wood NW is 50 mm, the overall thickness of the plastically processed wood PW is 40 mm and the compression rate is 30% when the compression is 20% of the overall thickness of 50 mm. When compressed, the overall thickness of the plastically processed wood PW is 35 mm, and when the compression rate is 40%, the overall thickness of the plastically processed wood PW is 30 mm.

In addition, if the peripheral edge part 10a of the upper press board 10A and the peripheral edge part 10b of the lower press board 10B are comprised, for example with the jig | tool for controlling thickness, a formwork, a gauge, etc., it will be set as desired of the plastic processing wood PW. The height of the peripheral portion 10a of the upper press panel 10A and the peripheral portion 10b of the lower press panel 10B can be adjusted according to the finished thickness. Further, at this time, for example, a regulating tool (spacer) (not shown) for regulating the extension in the lateral direction (horizontal direction) can be disposed on the side surface side of the surface hydrous wood WW. By restricting the change of the surface hydrous wood WW in the horizontal direction (horizontal direction) by the restricting tool, that is, the change in the direction perpendicular to the compression direction, it becomes easy to fix to a specific size and specific gravity. Variations in quality can be prevented and high quality can be ensured. In the case of such regulation, the density may increase at the end in the width direction of the wood. On the contrary, when the regulation is not performed, the density of the end portion in the width direction of the wood may be lower than that at the center side. Depending on the density difference in the width direction of the wood, it is possible to cut the surface on the end side in the width direction of the wood after the consolidation.

Next, in the sealed state of the internal space IS shown in FIG. 9D, the compression pressure of the upper press panel 10A and the lower press panel 10B is maintained, and the upper press panel 10A and the lower press panel 10B are kept at a predetermined temperature (for example, 110-210 [° C.]), fixing of the heat compression treatment of wood, so-called wood fixation processing is performed.
For example, a predetermined vapor pressure is supplied to the sealed internal space IS through the pipe 12 and the pipe port 12a (FIG. 8) connected to the valve V4, and the upper press board 10A and the lower press board 10B are compressed. The sealed internal space IS is kept at a predetermined temperature and vapor pressure for a predetermined time (for example, 20 minutes to 90 minutes) 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. Retained. High temperature steam at a predetermined temperature (eg, 110 to 210 [° C.]) is introduced into the internal space IS, and the sealed internal space IS is set at a predetermined temperature and vapor pressure, thereby being sealed by the action of high temperature and high pressure steam. A sufficient chemical change is caused in the whole heat-compressed wood arranged in the interior space IS to make the properties uniform. Thereby, plastic processing wood PW which does not return when the subsequent cooling compression is canceled can be formed.

At this time, high-temperature and high-pressure steam pressure can freely enter and leave the peripheral surface of the surface water-containing wood WW and the inside thereof, but depending on the water content of the heat-compressed wood, the upper press board 10A and the lower press board 10B. The internal space IS that is in a sealed state may be adjusted to have a predetermined vapor pressure. For example, excess moisture in the internal space IS based on the moisture content on the front and back sides of the front and back wet wood W is removed, and the internal space IS is adjusted to have a predetermined vapor pressure. At this time, when the wood compressed by heating and compression is performed in the sealed state of the internal space IS, the vapor pressure in the internal space IS is detected by the pressure gauge P2 as the vapor pressure control process, and the valve V5 is appropriately set. Open and close. Accordingly, 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. In addition, a predetermined vapor pressure can be appropriately supplied to the sealed internal space IS as necessary.

Then, as shown in FIG. 9 (d), the valve V5 is opened as a vapor pressure control process immediately before shifting from the heating compression to the cooling compression by the upper press panel 10A and the lower press panel 10B. High-temperature and high-pressure steam is discharged from the compression space IS to the drain pipe 14 side through the port 13a and the pipe 13. Thereby, the heat compression processing of wood, that is, so-called immobilization of wood is further promoted. At this time, the supply of water vapor for maintaining the upper press panel 10A and the lower press panel 10B at a specific temperature is also temporarily stopped.

Finally, as shown in FIG. 9 (e), the upper press panel 10 A and the lower press panel 10 B are passed by passing cooling water at room temperature through the piping path 15 of the upper press panel 10 A and the piping path 16 of the lower press panel 10 B. 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 disk 10A relative to the lower press disk 10B on the fixed side is maintained at the same predetermined pressure (for example, 2 to 5 [MPa]) as the pressure at the time of heat compression, and the upper press disk 10A and the lower press board 10B are cooled.
Thereafter, as shown in FIG. 9 (f), the upper press board 10A is raised with respect to the lower press board 10B on the fixed side, and the plastic processed wood PW which is the finished product is taken out from the internal space IS, and a series of processing steps are performed. finish.

Thereafter, if necessary, in order to ensure flatness, only one surface of the surface layer portion F may be cut, or both surfaces (front and back surfaces) and side surfaces of the surface layer portion F and the back layer portion R may be formed. Cutting may be performed. Further, if necessary, surface coating with a resin or the like may be applied as a countermeasure against moisture and dirt.

A plastically processed wood PW in which the wood NW is consolidated by heat compression in the direction perpendicular to the length direction of the wood grain of the wood NW by the manufacturing method described above, and has a high density with a high compression ratio by heat compression A surface layer portion F that is a dark color region, a back layer portion R that is formed on the surface opposite to the surface layer portion F, and is a medium density dark color region that has a lower compression ratio than the surface layer portion F, and a surface layer portion F The inner layer portion I is a low-density light-colored region that is formed between the outer layer portion R and the back layer portion R, and has a compression ratio by heat compression lower than that of the surface layer portion F and the rear layer portion R, and exhibits a light color tone. It is possible to produce plastically processed wood PW in which the density gradually changes from a high density state to a low state from the surface of the surface layer portion F and the back layer portion R toward the inside of the wood.

In this way, in the consolidation of the wood that is heated and compressed by surface contact with the upper press board 10A and the lower press board 10B and held in the sealed internal space IS, it is compressed and deformed with high efficiency and returned after compression. Since there are few, we can provide high-quality products stably.
However, when implementing this invention, it is not limited to the manufacturing method mentioned above, For example, the manufacture using a compression roller and a rolling roll may be sufficient.

As described above, the plastically processed wood PW according to the above embodiment is a plastically processed wood PW obtained by plastically processing the wood NW by heat compression in a direction perpendicular to the length direction of the grain of the wood NW. The surface layer portion F and the back layer portion R are heated and compressed at a compression ratio higher than that of the inner layer portion I interposed between the surface layer portion F and the back layer portion R. And the inner layer part I are composed of a three-layer surface compression material, and the bending of the annual ring line RL formed at the boundary between the surface layer part F and the inner layer part I and the boundary between the inner layer part I and the back layer part R appearing on the lumber surface of the wood. It has points f ₁ and f ₂ .

The plastically processed wood PW of the above embodiment is a plastically processed wood PW obtained by plastically processing the wood NW by heat compression in a direction perpendicular to the length direction of the grain of the wood NW, and is compressed by heat compression. The surface layer portion F, which is a high-density dark color region having the highest rate, and the back layer portion, which is formed on the opposite surface side of the surface layer portion F, is a medium-density dark color region whose compression ratio by heat compression is lower than that of the surface layer portion F R, and interposed between the surface layer portion F and the back layer portion R, the compression ratio by heat compression is lower than the surface layer portion F and the back layer portion R, and a lighter color tone than the surface layer portion F and the back layer portion R. And an inner layer portion I which is a low density light color region to be exhibited.

The plastically processed wood PW according to the above embodiment is heated and compressed in a direction perpendicular to the length direction of the wood grain of the wood NW, and the surface layer thereof in the thickness direction from the front surface side to the back surface side on the opposite surface side. This is a plastic working that increases the compression ratio on the side and back layer side and lowers the compression ratio between them, so that the surface layer side and the back layer side are easily compressed and the inside of the wood is difficult to compress, and the inside of the wood is compressed. It is designed to make it difficult to be stressed by. Furthermore, the surface layer portion F has the highest compression ratio and the high density, the back layer portion R opposite to the surface layer portion F has a lower compression ratio than the surface layer portion F, and is compressed by the surface layer portion F and the back layer portion R. Since there is a difference in rate, the concentration of stress inside the wood with respect to the heat compression force applied in the thickness direction of the wood is relaxed.

Thus, since the plastically processed wood PW of the above embodiment has reduced compression stress inside the wood, even if the node K is present, an excessive compressive force is applied to the entire structure of the node K. In particular, no excessive stress is applied to the fiber of the node K inside the wood. Even in the case where the inside of the wood is difficult to compress in this way, the fibers of the wood structure are softened and deformed around the node K due to the high moisture absorption / release characteristics of the node K and the surrounding area during the heat compression process. It is easy to do, and the movement of the node K due to the heat compression force is not restricted.

Therefore, according to the plastically processed wood PW of the above embodiment, even if the node K is present, excessive stress is not applied to the node K and the surrounding fibers within the wood, and the heat compression force is applied. The occurrence of stress at the node K is also small, so that the inclination, buckling, crushing, destruction, etc. of the node K and the surrounding fibers are difficult to occur, and cracks (cracks, cracks) in the wood are difficult to occur.

In particular, the surface layer portion F has a compression ratio in the range of 45% to 65% with respect to the air dry density of the original wood NW by heat compression, and the back layer portion R has a compression ratio with respect to the air dry density of the original wood NW. The compression ratio is in the range of 15% to 40%, and the inner layer portion I is compressed in the range of 10% to 30% in terms of the compression ratio with respect to the air dry density of the original wood NW by heat compression. Therefore, there are no cracks (cracks) regardless of the difference in the wood grain of the wood plank or remembrance material, even if the occupancy of the node K is as high as 10% to 20%. For example, even when used as a flooring or the like, a plastically processed wood PW having practically sufficient hardness and strength that is hardly scratched or dented and has stable wood properties is obtained.

Further, according to the plastically processed wood PW of the above-described embodiment, the surface layer portion F can be used as a high-density plastic processing region with the highest compression rate, and the ease of scratching of the original wood NW can be eliminated. Since the three-layer structure in which the inner layer portion I is sandwiched in parallel by the surface layer portion F and the back layer portion R having a high compressibility, the mechanical strength can be increased more than the original wood NW. And since the inner layer part I is sandwiched between the front layer part F and the back layer part R having a higher compression rate than the inner layer part I, the balance of the expansion and contraction rate is good on the front and back. In particular, when the surface of the wood having a large expansion / contraction rate is the surface layer portion F, the back layer portion R on the back side of the wood having a small expansion / contraction rate is lower than that of the surface layer portion F, while the high-density plastic working is performed. Therefore, the difference in expansion / contraction rate between the front and back of the original wood NW is reduced and balanced. Furthermore, even if the shrinkage and expansion force occurs due to the change in the ambient environment due to the high moisture absorption / release characteristics of the node K and its surroundings, the inner layer I is a low-density plastic working region with a low compression rate. Has a buffering action. Therefore, even if the ambient environment conditions change, the generation of internal stress is reduced.

Further, in the plastic processed wood PW of the above embodiment, the density distribution in the thickness direction from the surface layer portion F side to the back layer portion R side on the opposite surface side is the surface side of the surface layer portion F and the back surface of the back layer portion R. Since the density gradually changes from a high state to a low state from the side to the inside, there is no abrupt change in the density difference in the thickness direction of the wood. It is hard to occur.

Therefore, the plastically processed wood PW of the above embodiment has less stress applied to the node K due to changes in the surrounding environmental conditions even when the node K is present, and cracks in the node K and its surroundings, This is a countermeasure that does not cause cracks in the wood (cracks, cracks), is less likely to cause distortion as a whole, and has high dimensional shape stability.

In particular, when the thickness of the inner layer portion I is in the range of 2 to 5 times the thickness of the surface layer portion F and the thickness of the back layer portion R is in the range of 0.5 to 1 times, In the measurement on the surface or the memorial surface, for example, even when a large node K having a diameter of 1 cm or more exists penetrating in the thickness direction, or even when the occupation rate of the node K is 10% to 20%, The compressive stress applied to the node K is small, and the fiber of the node K is not easily buckled, crushed or broken. Even when the node portion K penetrates in the thickness direction, remarkable darkening and blackening of the node portion K and its surroundings due to compression are suppressed, and the surface design is ensured. Further, since the balance between the thicknesses of the front and back surfaces and the compression rate is improved, internal stress concentration due to the difference in expansion / contraction rate when the ambient environmental conditions change can be suppressed.
Further, the air dry density of the inner layer portion I is 0.35 to 0.65 times the air dry density of the surface layer portion F, and the air dry density of the back layer portion R is 0.6 to 0.8. If it is within the double range, the overall expansion / contraction rate is well balanced, and internal stress generation due to contraction / expansion of the wood when the ambient environmental conditions change can be reduced.
Therefore, even when the node K is present at a high occupancy rate of 10% to 20% on the wood, the stress due to the difference in contraction and expansion rate when the ambient environmental conditions change causes the node K and its surroundings. Thus, no cracks (cracks, cracks) are generated, and stable quality is ensured.

In addition, even when a plurality of plastically processed wood PWs are joined together in the width direction by matching the length direction of the grain, a large size of wood (plate material) is formed, and the shrinkage and expansion rate is increased in the width direction. Since it is substantially equal, a load is not applied to the joint surface due to a change in ambient environmental conditions, and it is difficult to generate a large stress. Therefore, even when the node K is present, it is difficult to cause cracking or distortion of wood. .

In addition, it is difficult for excessive stress to be applied to the entire node K in this way, so that even when the ambient environmental conditions change after the product is manufactured, a large amount of resin does not precipitate from the node K, which is caused by the precipitation of the resin. There is no decline in product value. Furthermore, since the entire node K is not highly compressed, remarkable darkening and blackening of the node K and its surroundings can be suppressed, and a good appearance can be maintained.
Naturally, an increase in weight due to a decrease in the overall volume of the original wood NW and an increase in the overall specific gravity is suppressed, and the yield is also good.

Furthermore, the above embodiment is a plastically processed wood PW obtained by plastically processing the wood NW by heat compression in a direction perpendicular to the length direction of the grain of the wood NW, and the surface layer portions on both sides that are heat-compressed. F and the back layer portion R on the opposite side thereof exhibit a darker color tone than the inner layer portion I due to a higher compression ratio than the inner layer portion I interposed between the surface layer portion F and the back layer portion R. On the boundary line BL ₁ between the surface layer portion F and the inner layer portion I and on the boundary line BL ₂ between the inner layer portion I and the back layer portion R, there are the bending points f ₁ and f ₂ of the annual ring line RL, and the surface layer portion F and the inner layer The bending degree f ₁ of the annual ring line RL on the boundary line BL _{1 of the} part I is larger than the bending degree of the bending point f ₂ of the annual ring line RL on the boundary line BL _{2 of the} back layer part R and the inner layer part I. It can also be regarded as an invention of plastically processed wood PW.

In this way, the surface layer portion F and the back layer portion R exhibit a dark color tone with a higher compression ratio than the inner layer portion I, and the bending point f ₁ of the annual ring line RL on the boundary line BL ₁ between the surface layer portion F and the inner layer portion I. The plastic working in which the degree of bending is larger than the bending point f ₂ of the annual ring line RL on the boundary line BL ₂ between the back layer portion R and the inner layer portion I is also compressible on the surface layer side and back layer side in the compression direction. And the inside of the wood in the meantime is a plastic processing that makes the compression ratio low, so that the surface side and the back layer side are easily compressed and the inside of the wood is difficult to compress, so that it is difficult to apply stress due to compression inside the wood It has been done. In particular, the degree of bending at the bending point f ₁ of the annual ring line RL on the boundary line BL ₁ between the surface layer part F and the inner layer part I is the bending point f of the annual ring line RL on the boundary line BL ₂ between the back layer part R and the inner layer part I. ₂ is a plastic working that is greater than the degree of bending of ₂ , and the plastic working in which the compressibility of the surface layer portion F and the back layer portion R is different, so that the concentration of internal stress is reduced during the heat compression treatment. .

In this way, the surface layer portion F and the back layer portion R exhibit a dark color tone with a higher compression ratio than the inner layer portion I, and the bending point f ₁ of the annual ring line RL on the boundary line BL ₁ between the surface layer portion F and the inner layer portion I. Since the plastic working in which the degree of bending is greater than the degree of bending at the bending point f ₂ of the annual ring line RL on the boundary line BL ₂ between the back layer portion R and the inner layer portion I is also reduced in compressive stress inside the wood. Even when the node K is present, an excessive compressive force is not applied to the entire tissue of the node K, and in particular, excessive stress is not easily applied to the fiber of the node K inside the wood. Even in the case where the inside of the wood is difficult to compress in this way, the fiber of the wood structure softens and deforms around the node K due to the high moisture absorption / release characteristics of the node K and the surrounding area during the heat compression treatment. The movement of the node K due to heat compression is not restricted easily.

Therefore, even when the node K is present, excessive stress is not applied to the node K and surrounding fibers inside the wood, and the generation of stress at the node K due to the heat compression force is small. Inclination, buckling, crushing, and destruction of the portion K and the surrounding fibers are unlikely to occur, and cracks (cracks, cracks) in the wood are unlikely to occur.

Also, the bending degree f ₁ of the annual ring line RL on the boundary line BL ₁ between the surface layer part F and the inner layer part I is the bending point f of the annual ring line RL on the boundary line BL ₂ between the back layer part R and the inner layer part I. _The plastic working larger than the degree of bending of ₂ is a process in which the surface layer portion F is made a high-density plastic working region with the highest compression rate, and the ease of scratching of the original wood NW can be eliminated. Furthermore, since the three-layer structure in which the inner layer portion I is sandwiched in parallel by the surface layer portion F and the back layer portion R having a higher compressibility than the inner layer portion I, the mechanically stable strength is obtained. The mechanical strength can be increased. And since the inner layer part I is sandwiched between the front layer part F and the back layer part R having a higher compression rate than the inner layer part I, the balance of the expansion and contraction rate is good on the front and back. In particular, the degree of bending at the bending point f ₁ of the annual ring line RL on the boundary line BL ₁ between the surface layer part F and the inner layer part I is the bending point f of the annual ring line RL on the boundary line BL ₂ between the back layer part R and the inner layer part I. _The plastic processing to be greater than the degree of bending of ₂ is that if the surface of the wood having a large expansion / shrinkage ratio is the surface layer F, it is a high-density plastic processing, while the back layer on the back of the tree having a small expansion / contraction rate Since R is a plastic working with a lower compression rate than the surface layer portion F, the difference between the expansion and contraction rates of the front and back of the original wood NW is reduced and balanced. Furthermore, even if the shrinkage and expansion force is generated due to the change in ambient environment due to the high moisture absorption / release characteristics of the node K, the inner layer I is a low-density plastic working region having a low compressibility, so that it has a buffering action. Have. Therefore, even when the ambient environment conditions change, the generation of internal stress is reduced.
Therefore, even when the node K is present, the stress applied to the node K due to changes in the surrounding environmental conditions is small, and it does not cause cracking of the wood (crack, crack). There is little occurrence, and the dimensional shape stability is high.

The plastically processed wood PW according to the present embodiment can be applied to a table top such as a floor, a deck, a waist plate, a dining table, or a school desk.
Moreover, although the said embodiment solves the problem of a node as plastic processing wood PW without a crack even when there is a node, naturally it is applied also to the wood without a node and commercialized as a product. As shown in FIG. 1 to FIG. 5 and the like, it can be applied with or without a node.

When the present invention is carried out, as the plastically processed wood PW, for example, cedar, pine (such as larch, dodo-pine, and ryukyuku), cocoon, firewood, walnut (walnut), yellow poplar, and the like are used. Is possible. In particular, cedar wood is widely distributed in Japan, and thinned wood can be easily obtained in large quantities, contributing to environmental conservation and easy to process. In addition, high hardness can be obtained by compaction, and when the wood is heated and compressed in the thickness direction of the wood, the wood does not extend in the width direction, so the density distribution in the width direction does not easily vary. Stabilization is possible.

In addition, since the numerical value quoted in the embodiment of the present invention does not indicate a critical value but indicates a preferable value suitable for implementation, even if the numerical value is slightly changed, the implementation is denied. is not.

F surface portion R backing layer portion I inner portion PW1, PW2, PW3, PW4 plastic working wood NW1, NW2, NW3, NW4 unprocessed wood RL annulus line BL _1, BL ₂ boundary f _1, f ₂ bend point

Claims

A plastically processed wood obtained by plastically processing the wood by heat compression in a direction perpendicular to the length direction of the wood grain;
The surface layer portion, the back layer portion, and the inner layer are compressed by a higher compression ratio than the inner layer portion that is interposed between the surface layer portion and the back layer portion. For the surface layer compression material consisting of three layers,
A plastically processed wood comprising: a boundary between the surface layer portion and the inner layer portion appearing on a lumber surface of the wood and a bending point of an annual ring line formed at a boundary between the inner layer portion and the back layer portion.
A plastically processed wood obtained by plastically processing the wood by heat compression in a direction perpendicular to the length direction of the wood grain;
A surface layer portion that is a high-density dark color region having the highest compression ratio by the heat compression;
A back layer portion that is formed on the side opposite to the surface layer portion, and is a medium density dark color region where the compression ratio by the heat compression is lower than that of the surface layer portion,
It is interposed between the surface layer part and the back layer part, and the compression ratio by the heat compression is lower than the surface layer part and the back layer part and exhibits a lighter color tone than the surface layer part and the back layer part. A plastically processed wood comprising an inner layer portion which is a density light-colored region.
The surface layer portion has a compression ratio in the range of 45% to 65% with respect to the air dry density of the wood by the heat compression, and the back layer portion has a compression ratio with respect to the air dry density of the wood of 15%. The inner layer portion has a compression ratio in the range of 10% to 30% in terms of the compression ratio with respect to the air dry density of the wood by the heat compression. The plastically processed wood according to claim 1 or 2.
The air dry density of the inner layer portion is in the range of 0.35 to 0.65 times the air dry density of the surface layer portion, and the air dry density of the back layer portion is 0.6 to 0.8 times. The plastic working wood according to any one of claims 1 to 3, wherein the plastic working wood is within a range.
A plastically processed wood obtained by plastically processing the wood by heat compression in a direction perpendicular to the length direction of the wood grain;
The heat-compressed double-sided surface layer part and the opposite back layer part are darker than the inner layer part due to a higher compression ratio than the inner layer part interposed between the surface layer part and the back layer part. An annual ring line on the boundary between the surface layer part and the inner layer part, which has a color tone and has a bending point of an annual ring line at the boundary between the surface layer part and the inner layer part and the boundary between the inner layer part and the back layer part that appears on the end face The plastically processed wood characterized in that the bending degree of the bending point of the wood is larger than the bending degree of the bending point of the annual ring line on the boundary between the back layer portion and the inner layer portion.
The density distribution in the thickness direction of the inner layer portion from the surface layer portion side to the back layer portion side on the opposite surface side is gradually increased from the surface side of the surface layer portion and the back surface side of the back layer portion toward the inside. The plastically processed wood according to any one of claims 1 to 5, wherein the plastically processed wood is changed from a high state to a low state.
2. The thickness of the inner layer portion is in the range of 2 to 5 times the thickness of the surface layer portion, and the thickness of the back layer portion is in the range of 0.5 to 1 times. The plastically processed wood according to any one of claims 6 to 7.