Semi-fireproof paneling and its manufacturing method

Abstract

The present invention makes it possible to improve the reliability of fire resistance with regard to wood materials containing a fireproofing treatment agent such as a semi-incombustible wood material while also improving both the ease of procuring raw materials and mass productivity. This panel board 11 comprises front / back veneer 21 constituting the front and back thereof and a core veneer layer 31 layered between the front / back veneer 21. The veneer fiber direction of the front / back veneer 21 is substantially parallel to the lengthwise direction of the panel board. The core veneer layer 31 is a layer obtained by stacking a plurality of sheets of core veneer 32 in the thickness direction. The veneer fiber directions of all of the sheets of the core veneer 32 are substantially orthogonal to the lengthwise direction of the panel board 11. The front / back veneer 21 has a thickness of 1.5-4.0 mm, and the thickness of the core veneer layer 31 is equal to or greater than the total thickness of the front / back veneer 21. Lathe checks and cracks are exposed on the board grain surfaces of all the front / back veneer 21, and an aqueous solution of a fireproofing agent is infiltrated therefrom.

Description

[Technical Field]

[0001] The present invention relates to a siding board having quasi-noncombustible properties and a method for manufacturing the same. [Background technology]

[0002] (Current status of semi-non-combustible or flame-retardant wood) Most chemical-impregnated wood available today is manufactured by impregnating wood materials with chemicals to provide preservatives, insecticides, flame retardancy, and semi-combustibility. For example, when chemicals are injected into lumber or laminated lumber lamina, incising processes are sometimes used to slightly increase the area of ​​chemical injection, but the degree of chemical penetration varies greatly between the heartwood and sapwood. As a result, the performance of chemical-impregnated wood and wood products varies greatly, and some products have been found to fail to meet the standards for chemical-treated wood. When fire-retardant and semi-combustible treated wood materials with insufficient chemical injection reach temperatures of around 200°C or higher, flammable gases are generated from the wood tissue in the insufficient areas, which ignite and significantly reduce the fire resistance of the wood.

[0003] (Changes in the timber market in Japan today) Looking at the current timber market in Japan, the following changes can be seen: The market for detached wooden houses, the largest market for lumber, is shrinking due to the effects of a declining birthrate and aging population. On the other hand, in medium- to large-scale buildings where large numbers of people gather, such as public facilities, stores, offices, and accommodation facilities, there is a demand for spaces that can maintain a healthy humidity level of 50% to 60%, which is resistant to viruses and other microorganisms, while also creating a "comfortable" and "stylish image", and the market for wooden interior and exterior decoration is on the rise.In such medium- to large-scale buildings where large numbers of people gather, safety in the event of a fire is an important factor, so there is an increasing demand for wood that meets the stable performance of being "flame-retardant and semi-non-flammable".

[0004] (Problems with conventional products and technologies and their impact) Next, the technical problems and their impacts of the conventional products offered up until now can be summarized as follows:

[0005] In conventional fire-retardant and semi-fire-resistant wood products, there are some parts where the amount of fire-retardant treatment chemicals injected is insufficient. As a result, there are many products that lack performance, and the reliability of the performance of fire-retardant and semi-fire-resistant wood is undermined. In order to meet the minimum injection amount standard, excessive injection of fire retardant agents is carried out, resulting in increased costs and efflorescence on the product surface.

[0006] (Basic technical knowledge) The technical basics of the present invention are as follows: Knowledge of the fact that little liquid water or aqueous solutions move through wood except in sapwood. Knowledge of the fact that liquid water or aqueous solutions move mainly in the direction of the grain through wood, and that movement perpendicular to the grain is extremely slow. In the case of laminated veneer lumber, the solution does not move across the fibers in the direction perpendicular to the grain, but rather through cracks in the back of the veneer and smaller cracks that occur along the grain at a slight angle from the length direction due to the manufacturing process using the rotary lathe. As a result, it was discovered that the solution appears to move in the horizontal direction as well. There are three types of chemical injection treatments depending on the purpose of the chemical treatment, but a clear distinction should be made between insect control treatment (chemical injection into the sapwood where there is a lot of insect nutrients such as starch), preservative treatment (chemical treatment only on the peripheral parts of the wood), and semi-fireproof / flame-retardant chemical treatment (chemical injection into the wood uniformly), and treatment that is suitable for semi-fireproof / flame-retardant chemical treatment (chemical injection into the wood uniformly) should be carried out. - Fire-retardant and semi-fire-resistant treated wood injection agents often have factors that inhibit adhesion, and when adhesive is applied after injection, it is often the case that sufficient adhesive strength is not obtained for the intended purpose.

[0007] (Prior art documents and their issues) Prior art documents related to such fire-resistant modified wood materials include Patent Documents 1 to 5, but no proposals have been made that accurately grasp the mobility of liquid in the fiber direction and utilize this mobility.

[0008] Specifically, paragraph 0014 of the specification of Patent Document 1 sets the immersion treatment time within a wide range of 6 to 72 hours, citing that the diameter and arrangement of vessels vary depending on the type of wood, and pointing out that the vessels in the sapwood are thick and coarse in density as a specific example. However, paragraphs 0022 and following of the specification use only cedar and paulownia boards as raw wood materials. Cedar, which is described as having vessels, does not actually have vessels. Furthermore, paulownia is a diffuse-pore broadleaf tree, allowing for the injection of aqueous solutions around the vessels in the sapwood. The very idea that the vessels in cedar and paulownia have thick vessels and low in density is questionable. Thus, Patent Document 1 does not disclose a laminated veneer structure for siding that takes into account the migration of water-soluble chemicals in the fiber direction and is suitable for siding.

[0009] In Patent Document 2, paragraph 0011 of the specification indicates that the vessels and their surrounding areas are sufficiently impregnated with a fireproofing agent, but in the examples from paragraph 0017 onwards, only paulownia wood boards are used as the raw material, and no distinction is made between the heartwood and the sapwood. In other words, Patent Document 2 is recognized as disclosing the technical idea that, even without distinguishing between the heartwood and the sapwood, the fireproofing liquid impregnated in the paulownia wood and the tannins potentially impregnated in the paulownia wood form a glass-like film that is presumably formed by a cross-linking reaction caused by heat, thereby significantly improving the non-flammable properties. Furthermore, the inventors have never heard of paulownia wood having tannins that are unique to the wood, and believe that even if a cross-linking reaction occurs, the wood remains an organic substance and is not affected by its flame resistance. Thus, Patent Document 2 does not disclose a laminated veneer structure for siding that takes into consideration the movement of water-soluble chemicals in the fiber direction.

[0010] Patent Document 3 proposes a method of injecting a chemical solution into a veneer, characterized in that a chemical solution is applied only to the areas of a plurality of recess-forming protrusions, and the protrusions are pressed against a dried veneer, compressing the veneer to its thickness or less and bringing the chemical solution into contact with the veneer, and then the protrusions are removed from the veneer, allowing the chemical solution to penetrate into the tissue of the veneer. However, with the method in Patent Document 3, it is unlikely that the chemical will penetrate into the wood, and even if the chemical solution is applied only to the areas of the recess-forming protrusions, there is almost no movement of the chemical solution into the heartwood. Thus, Patent Document 3 does not disclose a laminated veneer structure for siding that takes into consideration the movement of water-soluble chemicals in the fiber direction.

[0011] Patent Document 4 proposes forming continuous or discontinuous cavities and grooves in the lengthwise direction of the plate material in the laminated portion of the plate material, excluding the front and rear portions of the square plate, injecting a filler material into some of these cavities or grooves to form a large number of wall constituent members, stacking these wall constituent members vertically and connecting them with a joining means, and then injecting a filler material into the unfilled portions of the cavities or grooves to close the joint gaps between the wall constituent members and construct an integrated wall. However, in Patent Document 4, while a chemical solution can be injected into the cavities or grooves formed between the plate materials, it is not possible to inject the chemical solution into the interior of each plate material, and movement of the chemical solution within each plate material cannot be expected. Thus, Patent Document 4 does not disclose a laminated veneer structure for siding that takes into consideration the movement of water-soluble chemicals in the fiber direction.

[0012] In Patent Document 5, a chemical solution is dripped into grooves cut into the back of each of the four sides of a piece of wood by sawing, and then poured into the interior of the wood. Furthermore, holes are drilled into each of the four sides of the wood at right angles to the back split, and the resin that flows into the interior of the wood enters the horizontal holes and becomes a rib. The paper also proposes wood and processed wood products in which the surface is also treated with a chemical solution once the synthetic resin liquid has hardened. However, even in Patent Document 5, the heartwood and sapwood are not distinguished, making it difficult for the chemical solution to move through the heartwood. Furthermore, the grooves cut into the back of the wood by sawing are cut along the direction of the wood's fibers, so it is almost impossible to expect the chemical solution to move between the grooves. Thus, Patent Document 5 does not disclose a laminated veneer structure for siding that takes into consideration the movement of water-soluble chemicals in the fiber direction.

[0013] (Current utilization of cedar resources in Japan) Turning now to cedar, Japan's representative coniferous resource, there are large quantities of it in the country. Currently, the main product of cedar in Japan is posts and beams made by sawing the center part of cedar logs into shapes called "kokoromochi" or "kokoro-sari." On the other hand, the sapwood was traditionally used to make sheathing boards, but as that demand has been taken up by plywood, there is no longer any use for it. As mentioned above, the heartwood of conifers, including cedar, is a biological material, and therefore has a cellular structure that prevents foreign substances from penetrating from the outside. The sapwood, where the tree's vital activities take place, has a structure that is suitable for moving water from the ground to the leaves, and in the wood of the sapwood, chemical solutions move easily in the direction of the fibers. Specifically, with normal vacuum-pressure injection, the aqueous solution chemical penetrates only about 50 mm in the direction of the grain and only about 5 mm perpendicular to the grain, except for the sapwood of cedar. On the other hand, preliminary tests conducted by the inventor have confirmed that in the sapwood of cedar, the aqueous solution chemical penetrates more than 100 mm in the direction of the fibers and more than 5 mm perpendicular to the fibers with normal vacuum-pressure injection.

[0014] (Prior inventions and patent applications) Based on this finding, the inventor completed the invention of semi-non-combustible or flame-retardant wood and filed a patent application for Japanese Patent Application No. 2018-226298 on December 3, 2018, which was published as Patent Document 6. The invention of Patent Document 6 aims to provide semi-fireproof or fire-retardant wood that can exhibit uniform fire resistance and a manufacturing method thereof. It aims to provide semi-fireproof or fire-retardant wood made only from sapwood of conifers such as cedar or diffuse-hole hardwoods. Injection holes of a predetermined depth are formed at appropriate intervals in the wood, and the pieces of wood are laminated with adhesive, with the overlapping surfaces facing inward. By injecting a water-soluble or other fire-retardant agent under reduced pressure or pressure into the laminated wood processed in this way, semi-fireproof or fire-retardant wood with uniform and stable fire resistance throughout can be obtained.

[0015] The semi-non-combustible or non-combustible wood of the invention according to Patent Document 6 is a 20mm thick laminated wood of cedar plain sapwood, and the surface is made of plain plain wood, so it has a very good appearance, and the injection holes of 3mm width and 5mm depth on both sides of the laminated surface do not cause any problems in appearance. The injection amount of the non-combustible agent is 25% concentration, 140-150kg / m 3 When the necessary amount of quasi-noncombustible material was injected, a quasi-noncombustible combustion test was conducted, and the results were all satisfactory in terms of heat generation and the presence or absence of cracks extending to the back surface. However, this invention has the problem that since only sapwood is used, there is a limit to the amount of raw wood that can be harvested from a single tree. Furthermore, when perforating LVL as a means of uniformly injecting an effective amount of chemicals, it is impossible to avoid the effect of a decrease in the bending Young's modulus due to cross-sectional loss, and this effect cannot be ignored, particularly when used as a structural material. However, no prior art documents have disclosed or suggested this point.

[0016] (deadline) Furthermore, conventional semi-fireproof wood interior materials have large variations in the amount of chemicals injected depending on the part of the wood (sapwood or heartwood), making it impossible to produce ready-made products. This required a process of inquiry, business negotiations, material procurement, material selection, chemical injection, product selection for injection, product drying, and finishing, which meant it took six months to a year from the time of business negotiations to delivery. Furthermore, depending on the material, it was sometimes difficult to inject the required amount of chemicals, and the material had to be discarded, resulting in poor yields and high costs. These extremely long delivery times and extremely high costs were obstacles to the widespread use of semi-fireproof wood. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Japanese Patent No. 4221599 [Patent Document 2] Japanese Patent Publication No. 2007-63749 [Patent Document 3] Japanese Patent No. 3344703 [Patent Document 4] Japanese Patent Publication No. 11-131635 [Patent Document 5] Japanese Patent Publication No. 8-281203 [Patent Document 6] Japanese Patent Publication 2020-89978 Summary of the Invention [Problem to be solved by the invention]

[0018] The present invention aims to improve the reliability of fire resistance performance of siding boards containing fire retardant treatment agents while also improving the ease of procurement of raw materials and mass production. [Means for solving the problem]

[0019] The present invention was completed based on the following findings. First, in the sapwood of wood, aqueous solutions move through the membrane pores in the cell walls of conifers, while in hardwoods, they move through vessels where no filler is present. On the other hand, in the heartwood of wood, the membrane pores are closed in conifers, and in hardwood, intracellular filler material is present, making it impossible for aqueous solutions to move through the intracellular lumen. However, in laminated veneer lumber (LVL) made from rotary-cut veneer produced using rotary lathing, regardless of tree species or sapwood / heartwood, it has been found that in both cases, pressurized and decompressed aqueous solutions can penetrate approximately 100mm to 250mm in the direction of the fibers by passing through cracks and fissures in the veneer. Furthermore, it was found that when the aqueous solution infiltrated perpendicular to the grain, the solution did not move across the grain direction, but rather moved through cracks on the back of the veneer that had developed along the grain that was slightly inclined from the longitudinal direction, resulting in the appearance of the solution moving laterally as well.

[0020] Specifically, the present invention solves the above problems by providing a semi-fireproof siding board having the following features. The siding board of the present invention comprises front and back veneers constituting the front and back sides of the board, and a core veneer layer laminated between the front and back veneers. The fiber direction of the front and back veneers is approximately parallel to the length direction of the siding board. On the other hand, the core veneer layer is a layer in which a plurality of core veneers are stacked in the thickness direction, and the veneer fiber direction of all of these core veneers is approximately perpendicular to the length direction of the siding board. The front and back veneers have a thickness of 1.5 mm to 4.0 mm, and the thickness of the core veneer layer is equal to or greater than the total thickness of the front and back veneers. All of the front and back veneers have a fire retardant agent that has infiltrated from the grain of the veneer through cracks and fissures, while all of the core veneers have a fire retardant agent that has infiltrated through cracks and fissures that have developed along the fiber direction of the veneer.

[0021] In the present invention, the siding board raw material is prepared by laminating the veneers with a water-soluble adhesive to the above-mentioned predetermined dimensions, and then a fire-retardant agent is injected into the siding board raw material.

[0022] A water-soluble or other fire-retardant agent is injected under reduced pressure or pressure into the raw siding material obtained by laminating the veneers as described above. As a result, the agent penetrates into the front and back veneers from the grain surfaces of the veneers that form the front and back surfaces of the paneling material to the first adhesive layer (depth of 4 mm or less) on the front and back surfaces. Furthermore, the front and back veneers have many fine cracks due to the impacts applied during rotary lathing. Therefore, when stacking, the front and back veneers may be stacked with the back grain side (the side with the veneer back cracks) facing outward, or with the back grain side (the side without the veneer back cracks) facing outward. Regardless of which grain side is facing outward, by limiting the thickness of the front and back veneers to 1.5 mm to 4.0 mm, the fire retardant agent can penetrate through the cracks and cracks to the entire thickness.

[0023] Furthermore, the fiber direction of all the core veneers that make up the core veneer layer is approximately perpendicular to the length direction of the siding. Therefore, the end grains of all the core veneers are exposed on the left and right side surfaces (edge ​​surfaces) of the semi-fireproof siding, and the fire retardant treatment agent penetrates from these exposed side surfaces (edge ​​surfaces), and the agent that penetrates moves smoothly along the back cracks of the veneers that have occurred along the fibers, so that the agent is injected into the entire surface. Therefore, the semi-fireproof wood of the present invention comprises the core veneer layer in which the fireproofing agent is present, having migrated fluidically through the back cracks of the veneer that have occurred along the vessels and tracheids, and front and back veneers that are located above and below the core veneer layer and in which the fireproofing agent is present, having infiltrated from the tangential grain of both the top and bottom surfaces.

[0024] When the fire retardant solution is injected, it moves mainly through the cracks in the back of the veneer that occur along the inclined fiber direction, so its apparent movement in the direction perpendicular to the fiber is limited to 1 / 10 to 1 / 20 of the distance in the fiber direction. However, it can move a relatively long distance in the fiber direction, and the following infiltration state has been confirmed in preliminary experiments conducted by the inventor. For example, in cedar sapwood LVL, the chemical penetrates for a length of 150 mm or more in the grain direction. In LVL made with a mixture of cedar sapwood and cedar heartwood veneers, the chemical penetrates for a length of 150 to 200 mm in the grain direction. In LVL made with a mixture of poplar sapwood and poplar heartwood veneers, the chemical penetrates for a length of 150 to 200 mm in the grain direction. Therefore, in the core veneer layer, the chemical penetrates from the end grains on the left and right sides of each core veneer exposed on the left and right sides of the semi-fireproof siding. Therefore, regardless of the tree species (such as cedar or poplar) or the distinction between sapwood and heartwood, when rotary veneers are used, a width of 100 to 310 mm in the left and right direction allows the chemical to penetrate evenly from the left and right sides to the center of the width.

[0025] In the front and back veneers that make up the front and back of a siding board, the fiber direction of the veneer is roughly parallel to the length of the siding board, so the length of the fiber direction of the front and back veneers is longer than the length that the above-mentioned chemicals can penetrate. However, as mentioned above, the front and back veneers have cracks and fissures on the back of the veneer that have developed along the inclined fibers on both the front and back sides. Therefore, the chemicals penetrate through these cracks to a depth of about 5 mm.

[0026] The following production method can be used to manufacture semi-fireproof siding boards, for example. First, a laminate is produced by laminating the front and back veneers and the core veneer layer to a width convenient for the production factory, and this laminate is then cut to the specified width for the siding board before injecting chemicals. Chemicals are then injected into the cut siding board raw material of the specified dimensions. The other production processes are essentially the same as conventional methods, and unlike when using raw materials derived from lumber, this eliminates the need for special lamination and bonding processes, including boring and slit cutting, making it suitable for mass production and significantly reducing costs.

[0027] In particular, experimental results have shown that it is possible to produce semi-fireproof wood even at thicknesses of 12 mm or more. Therefore, rather than producing sawn lumber products with four-sided processing thicknesses of 12 mm to 30 mm (twice) thick, producing laminated veneer lumber products with thicknesses of 12 mm to 15 mm using laminated veneer lumber improves cost competitiveness by suppressing the decrease in yield caused by planing processing. Furthermore, by applying a decorative veneer to the surface of a wide board, cutting it into narrow boards of the same width as the siding, and then injecting the chemicals into the board, it is possible to produce semi-fireproof decorative siding at low cost.

[0028] Furthermore, the present invention provides a method for manufacturing semi-fireproof siding boards that can dramatically shorten delivery times by carrying out the method described below. First, a stock semi-fireproof siding board is manufactured. The stock semi-fireproof siding board is made by injecting a fireproofing agent into stock siding board raw material, which has the same laminate structure and thickness as the semi-fireproof siding board to be delivered, and then drying and curing it. However, at least one of the width and length dimensions of this stock semi-fireproof siding board is larger than that of the semi-fireproof siding board. Then, the semi-fireproof siding boards for stock that are in stock in advance are cut in either width or length to manufacture the semi-fireproof siding boards to be delivered. The stock semi-fireproof siding board has a thickness of 30 mm or less and a width of 310 mm or less, and the thickness of the front and back veneers that make up the front and back of the stock semi-fireproof siding board is suitably 1.5 mm to 4.0 mm.

[0029] The semi-fireproof siding board of the present invention can be uniformly infused with chemicals in any direction, including thickness, length, and width. This allows for the production of pre-made semi-fireproof siding boards by injecting chemicals into stock siding board raw materials of a specified size (e.g., thickness: 12-30 mm, width: 310 mm, length: 4100 mm) and drying them. This allows for the pre-made semi-fireproof siding boards to be cut to the order size and delivered upon receiving an order from a customer. As a result, the delivery time for semi-fireproof siding boards, which previously required six months to a year from the conclusion of a business deal to delivery, can now be shortened to the time required for cutting and packaging, enabling the development of a new business model in which delivery can be achieved within approximately 10 days after receiving an order. [Effects of the Invention]

[0030] The present invention provides a semi-fireproof siding board and a manufacturing method thereof that can improve the reliability of the fire resistance of siding boards containing fireproof treatment agents such as semi-fireproof wood, while also improving the ease of procurement of raw materials and mass production. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a perspective view of a semi-fireproof siding board according to an embodiment of the present invention. [Figure 2] Plan view of each layer of the semi-fireproof paneling. [Figure 3] (A) An explanatory diagram of the cross-sectional structure of a log for obtaining lumber for semi-fireproof lumber according to an embodiment of the present invention, (B) An explanatory diagram of the cross-sectional structure of a log for obtaining lumber for semi-fireproof lumber according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0033] The semi-fireproof siding board 11 according to this embodiment has a front and back surface 12, front and rear end surfaces 13, and left and right side surfaces 14, as shown in FIGS. The front and back surfaces 12 of the siding board 11 are made up of front and back veneers 21. A core veneer layer 31 is disposed between the front and back veneers 21, and a plurality of core veneers 32 are laminated. These front and back veneers 21 and core veneer 32 are bonded together by a water-resistant adhesive or the like in accordance with a standard method.

[0034] (About front and back veneer 21) The grain direction of front and back veneer 21 (arrow S in Figure 2) is approximately parallel to the length direction of siding board 11, and like a normal LVL siding board, its butt faces (end faces approximately perpendicular to the grain direction of the wood) are arranged at front and rear end faces 13 of siding board 11. The thickness of front and back veneer 21 is 1.5 mm to 4.0 mm.

[0035] (21 fire retardant veneers on both sides) In the front and back veneers 21, an aqueous solution of the fire retardant agent is present, which has soaked in through cracks and crevices on the back surface of the plain grain surface exposed on the front and back surfaces. Specifically, a solution of non-combustible, semi-non-combustible, or fire-retardant treatment agent is injected into the siding board 11, which has been finished to a predetermined size, using a reduced pressure injection can. In this case, the front and back veneers 21 are exposed on four surfaces, namely the front and back surface 12 of the siding board 11, as well as the front and back end surfaces 13 and the left and right side surfaces 14. Therefore, although the aqueous solution of chemicals is injected from these surfaces, the distance the aqueous solution of chemicals travels from the four surfaces, namely the front and back end surfaces (i.e., butt surfaces) 13 and the left and right side surfaces (i.e., edge surfaces) 14, is shorter than the total length of the siding board 11. However, because one surface of the front and back surface (i.e., cross grain surface) 12 of the siding board 11 is exposed entirely, the aqueous solution of chemicals from the front and back surface 12 seeps into the interior from that entire surface, passing through cracks and crevices in the wood.

[0036] (Regarding core veneer layer 31) All of the core veneers 32 constituting the core veneer layer 31 have a veneer fiber direction (arrow T shown in FIG. 2) that is substantially perpendicular to the length direction of the siding board 11. Unlike ordinary LVL siding, the butt end faces (the end faces that are approximately perpendicular to the direction of the wood grain) are exposed on the left and right side surfaces 14 of the siding 11. The thickness of the core veneer layer 31 is equal to or greater than the combined thickness of the two front and back veneers 21.

[0037] (Retardant agent for core veneer layer 31) All core veneers 32 have a fire-retardant treatment agent present throughout them, which has migrated via the back cracks of the veneer that have developed along the tracheids or vessels. Specifically, a solution of non-combustible, semi-non-combustible, or fire-retardant treatment agent is injected into the siding board 11, which has been finished to a predetermined size, using a reduced pressure injection can. At this time, the core veneer 32 is exposed on four surfaces: the front and rear end faces 13 and the left and right side faces 14. Therefore, although the aqueous solution of chemicals is injected from these surfaces, the movement distance of the aqueous solution of chemicals from the front and rear end faces 13 is shorter than the movement distance from the left and right side faces 14, because the fiber direction of the veneer (arrow T) is aligned with the width direction of the siding 11. However, the aqueous solution of non-combustible, semi-non-combustible, or fire-retardant treatment chemicals injected from the left and right side faces 14 can move a certain distance along the fiber direction of the veneer (arrow T). Specifically, preliminary tests by the inventor have confirmed that if the core veneer 32 is a veneer made from cedar sapwood, the chemical agent will penetrate for a length of 150 mm or more in the direction of the veneer fibers (arrow T), if it is a veneer made from cedar sapwood and core wood, the chemical agent will penetrate for a length of 150 mm to 200 mm in the direction of the veneer fibers (arrow T), and if it is a veneer made from poplar sapwood and core wood, the chemical agent will penetrate for a length of 80 mm to 200 mm in the direction of the veneer fibers (arrow T). In this way, by limiting the width of the siding 11 to within twice the distance that the aqueous solution of chemicals can move in the veneer fiber direction (arrow T) in the core veneer 32, the aqueous solution of chemicals injected from the left and right end faces of the core veneer 32 exposed on the left and right side surfaces 14 of the siding 11 can reach the entire width. Therefore, the aqueous solution of the drug can be uniformly distributed over the entire core veneer 32 with certainty.

[0038] (Wood 11 Production) Generally, wood is roughly divided into sapwood and heartwood, with sapwood referring to the whitish outer periphery of a log's cross section and heartwood referring to the reddish central portion of a log's cross section. More specifically, the heartwood can be divided into two regions: the immature central region and the mature central region. A white band may also be present at the boundary between the sapwood and heartwood. Therefore, as shown in Figure 3, wood can be divided into four regions from the outside: sapwood A, white band B, mature heartwood C, and immature heartwood D. In this invention, the term "heartwood" refers to the region including white band B, mature heartwood C, and immature heartwood D.

[0039] In the present invention, as shown in FIG. 3(A), the chemical agent penetrates not only into the sapwood A where fluid movement is good, but also into the heartwood where fluid movement is relatively poor, by 80 mm to 200 mm or more, as described above. Therefore, by selecting and using the optimal tree species and areas to be used depending on the desired width of the veneers 21, 32 of the siding board 11, it is possible to manufacture a siding board 11 in which the non-flammable, semi-non-flammable, and flame-retardant treatment agents are well distributed throughout the entire siding board 11. Of course, as shown in Figure 3(B), it is also possible to use only the sapwood part A, where the liquid moves well in the direction of the fiber inside the wood, or to use both parts without making any distinction.

[0040] For example, if a veneer made of cedar sapwood is used for the core veneer 32, if a veneer made of cedar sapwood and a veneer made of cedar heartwood are used together without distinction, or if a veneer made of poplar sapwood and a veneer made of poplar heartwood are used together without distinction, then regardless of the tree species or the distinction between sapwood and heartwood, for rotary veneers, it is appropriate that the overall thickness of the siding board 11 be 12mm to 30mm, the width be 100mm to 310mm, and the length be 2000mm to 4500mm.

[0041] (Drug injection) Chemical impregnation is the process of creating a siding board material of a specified size by laminating veneers with water-soluble adhesives, etc., as described above, and then injecting a fire-retardant chemical into the siding board material. Specifically, a vacuum / pressure injection tank is used to inject an aqueous solution of fire-retardant, semi-fire-retardant, or fire-retardant chemicals into the siding board material, completing the semi-fire-retardant wood. The amount of chemicals injected can be set depending on the dimensions of the front and back veneers 21 and the core veneer layer 31, the type of tree, and the region where it grew. In the case of Japanese cedar, the guideline is about 150 kg / m for a wood 11 with a thickness of 18 mm. 3 It is appropriate to do so.

[0042] Since the state of impregnation of the chemical solution varies depending on the type of wood and its growth condition, it is preferable to confirm the decompression conditions and time, pressurization conditions and time, and number of repetitions in preliminary experiments using a water-soluble colorant. In addition, it is preferable that the injection amount for process control is controlled by measuring the weight before and after injection and taking the difference as the average injection amount for the lot.

[0043] (Post-injection process) Curing: It is preferable to carry out curing including drying in order to level the inside of the wood of the injected chemicals, and the curing period is determined in a preliminary experiment. Drying: The moisture content is controlled to meet the product quality determined through agreements with the seller. Artificial drying is preferable to improve quality.

[0044] Finishing process: To meet the specified product requirements, the board width is finished with a rip saw, the length with a cross-cut saw, and the surface is finished with a sander or molder. Inspection: Carry out inspections necessary to ensure product quality. For example, thickness and width are measured with a vernier caliper, length with a steel tape measure, and appearance and surface texture are checked visually and by touch. Packaging: Semi-fireproof wood products are bundled together and wrapped on six sides to block moisture from the outside air, and are wrapped in plastic sheets and secured with tape to prevent damage to the cargo.

[0045] The quasi-noncombustible wood of this embodiment exhibits uniform and excellent fire resistance throughout the entire fire-resistant modified wood material. When wood material containing insufficiently injected chemicals is heated, it reaches a high temperature of approximately 200°C or higher, generating flammable gases from the wood structure in the insufficient areas, which then ignite. As a result, its fire resistance is significantly impaired. However, the siding board 11 of the present invention is impregnated almost entirely with a sufficient amount of fire-resistant chemicals, which prevents flammable gases from being generated from the wood structure, thereby providing stable fire resistance.

[0046] (Process management) When implementing the present invention, process control is important to ensure that all of the siding boards 11 produced exhibit consistent fire resistance. Check the infiltration length After pre-drying, 4 to 6 samples are taken from each production lot and a dyeing solution injection test is carried out to check the length of penetration of the agent.The test method involves injecting the dyeing solution under reduced pressure and pressure, then cutting the sample into 10cm lengths and checking the penetration of the dyeing solution on the cut surface.

[0047] ·Pre-injection moisture content measurement Since the moisture content before injection affects the impregnation of the chemical, it is important to measure the moisture content using a high-frequency moisture meter. Preferably, six test pieces are randomly selected for each production lot and measured using the completely dry method.

[0048] Drug injection amount measurement For each injection lot, the weight of the injection lot is measured before and after the decompression and pressurization process, and the difference is used as the average drug injection amount for that lot to confirm whether a sufficient amount of drug has been injected.

[0049] - Moisture content measurement after drying Six samples are taken for each production lot and weighed using the dry method. The moisture content is estimated by subtracting the average amount of chemicals from the measured weight. A correlation table is created between this value and the value from the high-frequency moisture meter, and the moisture content of small lots of the product is measured.

[0050] · Checking dimensional accuracy The thickness and width of the siding board 11 are measured with a vernier caliper. The accuracy is determined by agreement with the customer. Length of the siding board 11 = Measured with a steel tape measure. Accuracy is determined by agreement with the customer.

[0051] Product inspection Visual inspection of all products is carried out, the details of which are determined by agreement with the customer. · Checking packaging After the product is bound, all six sides are covered with plastic sheets to prevent it from coming into contact with the outside air. The goods are packaged in kraft paper and pallets as necessary to prevent damage during handling.

[0052] Check the display Attach a piece of paper with the following information written on it to the outer sides and front and rear ends of the packaging. Product name, product grade, raw material species, treatment chemical type, product dimensions, product quantity (number of pieces), producer name, production location, production lot number and bundle number.

[0053] (Quality control) In addition to the process control mentioned above, we also carry out thorough quality control and only ship products that demonstrate stable fire resistance performance.

[0054] Combustion test: Conducted in accordance with the Ministry of Land, Infrastructure, Transport and Tourism ordinance. Specifically, a cone calorimeter is used to measure the required number of particles under specified conditions. By recording the relative relationship between the cone calorimeter test results and the injection amount for each injection lot, the accuracy of process management can be improved.

[0055] - Chemical injection amount management: The amount of chemicals before and after chemical injection is managed (frequency = for each production lot). Specifically, the weight of the material placed on the cart before and after injection is measured, the difference is calculated and divided by the volume of wood, and the m 3 The average amount of drug injected per patient is used.

[0056] The core veneer 32 according to this embodiment can be implemented as a single board material, or as a plurality of pieces of wood arranged in the longitudinal direction of the siding board 11.

[0057] The biggest problem with semi-fireproof wood products is the stability of quality, as fireproof chemicals are not uniformly injected into the wood, resulting in inconsistent quality and products that do not contain an effective amount of chemicals, or the occurrence of efflorescence due to excessive chemicals being injected. I have heard from people in the construction industry that suppliers give irresponsible answers like, "Wood is a living material, so the quality is inherently inconsistent, so it can't be helped," and then deliver poor-quality materials without a second thought. On the other hand, interest in wooden buildings is rapidly growing due to the government's policy to reduce Japan's CO2 emissions to zero by 2050. By implementing this invention, it will be possible to mass-produce semi-fireproof paneling of stable quality and supply it at low cost. [Example]

[0058] Hereinafter, examples will be shown to enhance understanding of the invention, but the present invention should not be understood as being limited to these examples.

[0059] (Preparation of Samples 1 and 2 in the Examples) Poplar was used as the raw wood, and as described above in (Production of Lumber 11), a 1.7 mm thick veneer material was produced using a rotary lathe. This veneer material was then subjected to necessary processing such as cutting and laminating to produce siding boards 11 according to Samples 1 and 2, in which veneers 21 and 32 with the specified veneer fiber directions S and T were laminated. In this case, the sapwood portion A, the white line band B, the mature heartwood portion C, and the unripe heartwood portion D were used without distinction. Dimensions of panel 11 for sample 1: 12 mm x 110 mm x 1200 mm Dimensions of panel 11 for sample 2: 12 mm x 300 mm x 1200 mm

[0060] The injection amount varies depending on the tree species, veneer thickness, etc., and in practice it can be changed by adjusting the concentration of the chemicals. In this example, however, in accordance with the above description (Chemical Injection), the chemicals were injected into the siding 11 of Sample 1 and Sample 2 using a reduced pressure injection can under the following conditions, and then the siding was dried and cured to complete Sample 1 and Sample 2.

[0061] Drug injection conditions Injection agent: Phosphorus-nitrogen compound flame retardant W2-50 manufactured by Marubishi Yuka Co., Ltd., concentration 20% Decompression: 0.1 atmospheres, 1 hour Pressurization: 8.0 atmospheres, 1 hour

[0062] (Check the injection amount) The amounts of chemicals injected into 30 panels each of Sample 1 and Sample 2 were weighed and statistically analyzed to confirm the variations (average, standard deviation (σ) and average - 3σ). The results are shown in Table 1.

[0063] [Table 1]

[0064] In Table 1, all units are kg / m 3 is. Sample 1 overall (30 sheets) shows the overall variation (population size 30) for the 30 sheets of material 1. The division of sample 1 into 10 parts in the longitudinal direction (30 sheets x 10) shows the variation among all samples 1 (300 parameters) obtained by dividing each sample 1 into 10 parts at equal intervals in the longitudinal direction. Sample 2 overall (30 sheets) shows the overall variation for the 30 sheets of material 2. The left and right side portions of sample 2 (30 sheets x 2) show the variation of both the left and right side portions (parameter 60) when all samples 2 are divided into three at equal intervals in the width direction. The central portion of sample 2 (30 sheets x 1) shows the variation in the central portion (parameter 30) when all samples 1 are divided into 10 equal intervals in the longitudinal direction.

[0065] (Consideration) As a result, it was confirmed that there was no significant difference in the amount of chemical injected and its variation in the longitudinal direction, central part, and both sides. Therefore, it was confirmed that the chemical was injected uniformly throughout the entire siding board of the example. Specifically, the average -3σ is a value that 99.7% or more of the samples meet or exceed, and is generally considered to be the minimum guaranteed value. Therefore, in the evaluation of sample 1, it was confirmed that 99.7% was within a range of approximately ±11% both overall and in the longitudinal direction of the veneer. In addition, in the evaluation of sample 2, it was confirmed that there were no significant differences in the average value, standard deviation, or minimum guaranteed value both overall and in the transverse direction of the veneer.

[0066] Therefore, with the siding board of the present invention, it is possible to arbitrarily set the amount of chemicals injected by adjusting the concentration of the chemicals injected depending on the tree species and veneer thickness, and it was confirmed through the examples that the same performance can be guaranteed regardless of the thickness, length, or width. Therefore, even if a business model is implemented in which dried, ready-made products are produced and stored in sizes of 12mm to 30mm in thickness, 310mm in width, and 4100mm in length, and then cut to the ordered size and delivered when a customer places an order, the chemicals are injected uniformly throughout the delivered siding board, and it has been confirmed that the same performance can be guaranteed. [Explanation of symbols]

[0067] 11...Washboard 12...Front and back 13...Left and right sides 14…Front and rear end faces 21...Single-ply front and back 31...Core veneer layer 32...Solid core A...Sapwood part B: White line C…Heartwood ripening section D... Heartwood unripened part S...Veneer grain direction of front and back veneers T: Core veneer fiber direction

Claims

1. A siding board in which multiple rotary veneers are laminated without distinguishing between sapwood and heartwood, The front and back veneers that make up the front and back of the siding, A core veneer layer is laminated between the front and back veneers, The fiber direction of the front and back veneers is approximately parallel to the length direction of the siding board, The core veneer layer is a layer in which a plurality of core veneers are stacked in the thickness direction, The fiber direction of all of the core veneers is approximately perpendicular to the length direction of the siding board, The front and back veneers have a thickness of 1.5 mm to 4.0 mm, The thickness of the core veneer layer is equal to or greater than the total thickness of the front and back veneers; All of the above-mentioned front and back veneers are coated with a fire-retardant agent that has penetrated from the tangential surface through the cracks on the back of the veneer or the tiny cracks that occurred during veneer processing with a water solution. This semi-fireproof siding board is characterized in that all of the core veneers contain a fireproof treatment agent that has fluidly migrated along the fiber direction of the veneer within the back cracks of the veneer that have formed along the vessels or tracheids.

2. The core veneer is a rotary veneer, 2. The quasi-fireproof siding board according to claim 1, wherein the thickness of the entire siding board is 12 mm to 30 mm, the width is 100 mm to 310 mm, and the length is 2000 mm to 4500 mm.

3. A method for producing the semi-fireproof siding board according to claim 1 or 2, a stock siding board raw material having the same laminated structure and thickness as the semi-fireproof siding board and at least one of width and length dimensions being larger than that of the semi-fireproof siding board; and a fire-retardant treatment agent is injected into the stock siding board raw material to manufacture the stock semi-fireproof siding board; A method for manufacturing a semi-fireproof siding board, characterized in that the semi-fireproof siding board for stock is manufactured by cutting either the width dimension or the length dimension of the semi-fireproof siding board.

4. The stock semi-fireproof siding board has a thickness of 30 mm or less and a width of 310 mm or less, 4. The method for manufacturing a semi-fireproof siding board according to claim 3, wherein the thickness of the front and back veneers constituting the front and back of the stock semi-fireproof siding board is 1.5 mm to 4.0 mm.

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