Wood containing a non-combustible treatment agent and method for producing the same

Abstract

The present invention improves the reliability of fire-resistance performance, and suppresses a drop in strength and a drop in Young's modulus for bending, with regard to a structural LVL containing a fireproofing chemical for fire-resistant structural wood material-use. The present invention is the LVL 61 for structural use comprising a plurality of raw material veneers 51 layered in the front-back thickness direction via adhesive layers therebetween. Each of the raw material veneers 51 is a wood material having a fireproofing chemical injected to the interior thereof, and is constituted from a site of sapwood part alone, a site of heartwood part alone, or, a site wherein a sapwood part and a heartwood part are mixed. Injection holes 62 are provided, each having a circular cross section and extending in the thickness direction from each of the front surface and the back surface of the LVL 61. The injection holes 62 traverse through the plurality of raw material veneers 51 and the adhesive layers. On the front surface and on the back surface, respectively, a plurality of the injection holes 62 are aligned while leaving an interval therebetween in the width direction and in the length direction of the LVL 61. The injection holes 61(U) from the front surface and the injection holes 61(D) from the back surface are disposed at different positions from one another in the width direction and in the length direction.

Description

Technical Field

[0001] The present invention relates to wood containing a non-combustible treatment agent for a fire-resistant structure and a method for producing the same.

Background Art

[0002] (Current situation of semi-non-combustible or fire-retardant wood) Many of the currently distributed chemically treated woods are produced by impregnating wood materials with chemicals for anti-corrosion, insect-proofing, fire-retardant, and semi-non-combustible treatments. For example, by adopting a method of injecting chemicals into sawn timber products or laminates for glued laminated timber, incising is also carried out to slightly increase the chemically injected part. However, in sawn timber products and glued laminated timbers, the degree of chemical penetration varies greatly between the heartwood part and the sapwood part. As a result, there are significant variations in the performance of the chemically treated wood and the performance of the wood products, and some do not meet the chemical treatment wood standard values. When a wood material containing a non-combustible treatment agent for a fire-resistant structure in which there is an insufficient part of chemical injection is heated, when it reaches a high temperature range of 200 °C or higher, combustible gas is generated from the wood tissue of the insufficient part, and when the gas ignites, its fire resistance performance is greatly impaired.

[0003] (Changes in the wood market in Japan today) Looking at the wood market in Japan today, the following changes can be seen. The market for single-family wooden houses, which is the largest market for wood, is shrinking due to the impact of a declining birthrate and an aging population. On the other hand, in large-scale buildings where a large number of unspecified people gather, such as public facilities, stores, offices, and accommodation facilities, it is possible to create a "comfortable feeling" and a "fashionable image", and a space that can maintain a healthy humidity of 50% to 60% that is strong against microorganisms such as viruses is required, and the market for interior and exterior wood finishes is on an expanding trend. In such large-scale buildings where a large number of unspecified people gather, the safety at the time of a fire is an important factor, so the demand for wood that meets the stable performance of fire-resistant structure wood materials such as fire-retardant and semi-non-combustible is increasing.

[0004] (Problems of Conventional Products and Technologies and Their Impacts) Next, summarizing the problems of the technologies of conventional products provided to date and their impacts, it can be seen that the following situations exist.

[0005] · In the case of fire-retardant and semi-non-combustible wood materials such as fire-retardant and semi-non-combustible wood in conventional products, there are parts where the injection amount of the non-combustible treatment agent is insufficient. As a result, products with insufficient performance are also found, and the reliability of the performance of fire-retardant wood materials is impaired. · In order to make the minimum value of the injection amount the reference value, excessive injection of the non-combustible agent is carried out, resulting in cost increase and efflorescence on the product surface.

[0006] (Technical Basics) The technical basics of the present invention are as follows. · Knowledge regarding the fact that liquid water or aqueous solution hardly moves in wood except for the sapwood part. · Knowledge regarding the fact that the movement of liquid water or aqueous solution in wood is mainly in the fiber direction, and the movement in the direction perpendicular to the fiber is extremely slow. · Depending on the purpose of the chemical treatment, there are three types of chemical injection treatments. It is necessary to clearly distinguish the three types: insect-proof treatment (chemical injection for the sapwood part rich in nutrients for insects such as starch), anti-corrosion treatment (chemical treatment only for the peripheral part of the wood), and treatment with non-combustible treatment agents for fire-retardant wood materials such as semi-non-combustible and fire-retardant agents (uniform chemical injection treatment for wood), and perform the treatment suitable for the semi-non-combustible and fire-retardant agent treatment (uniform chemical injection treatment for wood). · Non-combustible treatment agents for fire-retardant wood materials such as fire-retardant and semi-non-combustible treated wood often have adhesion-inhibiting factors, and in many cases, sufficient adhesion for use cannot be obtained when adhered after injection.

[0007] (Prior Art Documents and Their Problems) As prior art documents regarding such fire-retardant modified wood materials, Patent Documents 1 to 5 can be cited. However, it is needless to say that they do not show a technology that clearly distinguishes the heartwood part and the sapwood part and uses only the sapwood part. Moreover, no proposal has been made that focuses on the fact that the liquid movement mechanism is completely different between the heartwood part and the sapwood part.

[0008] Specifically, in paragraph 0014 of the specification of Patent Document 1, a range with a large width of 6 to 72 hours is set for the time of performing the immersion treatment. As reasons, it is mentioned that the thickness and arrangement of the conduits vary depending on the type of tree, and as a specific example, it is pointed out that the sapwood part has thick conduits and a coarse density. However, in Patent Document 1, there is no distinction between coniferous trees and broad-leaved trees in the first place, so this is out of the question. Further, in the examples from paragraph 0022 onwards of the specification, only cedar boards and paulownia boards are used as the raw material wood, without distinguishing between the heartwood part and the sapwood part, and in the case of cedar described as if there were conduits, there are no conduits themselves, and in the case of paulownia, which is a diffuse-porous broad-leaved tree, an aqueous solution can be injected around the conduits in the sapwood part. There are doubts about the very recognition that the sapwood part in cedar or paulownia has thick conduits and low density. Thus, it is recognized that Patent Document 1 discloses the technical idea that, on the premise of not distinguishing between the heartwood part and the sapwood part, in other words, even without distinguishing between the heartwood part and the sapwood part, non-combustible wood boards can be manufactured by adjusting the treatment conditions.

[0009] Also in Patent Document 2, in paragraph 0011, it is shown that the conduits and the surrounding parts thereof are sufficiently impregnated with a fire retardant. However, in the examples from paragraph 0017 onwards of the specification, only paulownia boards are used as the raw material wood, without distinguishing between the heartwood part and the sapwood part. Thus, it is recognized that Patent Document 2 discloses the technical idea that, on the premise of not distinguishing between the heartwood part and the sapwood part, in other words, even without distinguishing between the heartwood part and the sapwood part, the non-combustible properties can be improved step by step by the formation of a glass-like film presumably formed by the cross-linking reaction of the fire-retardant chemical solution impregnated in the paulownia wood and the tannin potentially impregnated in the paulownia wood by heat. In addition, the inventor of the present case has never heard that there is tannin unique to only paulownia wood, and considering that it remains an organic substance even after the cross-linking reaction, there is no relation to the difficulty of burning.

[0010] In Patent Document 3, a method for injecting a chemical solution into a veneer is proposed, which involves attaching the chemical solution only to the portions of a plurality of projections for forming recesses, pressing the projections against the dried veneer, compressing the veneer to a thickness less than its original thickness while bringing the chemical solution into contact with the veneer, and then detaching the projections from the veneer to allow the chemical solution to penetrate into the tissue of the veneer. However, with the method of this Patent Document 3, it is difficult to consider that the chemical agent enters the interior of the wood, and the heartwood part and the sapwood part are not distinguished and used. Even if the chemical solution is attached only to the portions of the projections for forming recesses, almost no movement of the chemical solution occurs in the heartwood part.

[0011] In Patent Document 4, a method is proposed in which cavity portions and groove portions that are continuous or intermittent in the longitudinal direction of a square timber are formed in a laminated portion made of a wood board excluding the front and rear portions of the square timber, a filler is injected into a part of these cavity portions or groove portions to form a number of wall construction materials, these wall construction materials are stacked in the vertical direction and connected by connecting means, and then the filler is injected into the non-injected portions of the filler in the cavity portions or groove portions to close the joint gaps between the respective wall construction materials and construct an integral wall. However, in this Patent Document 3 as well, the heartwood part and the sapwood part are not distinguished and used, and almost no movement of the chemical solution occurs in the heartwood part. Moreover, in Patent Document 4, although the chemical solution can be injected into the cavity portions or groove portions formed between the wood boards, it is impossible to inject the chemical solution into the interior of each wood board, and the movement of the chemical solution inside each wood board cannot be expected either.

[0012] In Patent Document 5, a chemical solution is poured into grooves formed by kerfing on all four sides of the wood, and is made to flow into the interior of the wood. In addition, holes are drilled from all four sides of the wood at right angles to the kerfing, and the resin that has flowed into the interior of the wood enters the horizontal holes and serves as a cross member. Wood and wood processed products whose surfaces are also treated with the chemical solution when the synthetic resin liquid has hardened are proposed. However, in this Patent Document 5 as well, the heartwood part and the sapwood part are not distinguished and used, and it is difficult for the chemical solution to move in the heartwood part. Moreover, the grooves formed by kerfing are provided along the direction in which the fibers of the wood extend, and almost no movement of the chemical solution between the grooves can be expected.

[0013] (Utilization Status of Cryptomeria Resources in Japan Today) Looking at Cryptomeria, a representative resource of coniferous trees in Japan, there are a large number of resources in Japan. Currently, the main products of Cryptomeria in our country are column materials and beam materials obtained by sawing the central part of Cryptomeria logs into forms called "kokomochi" and "kokosari". On the other hand, the sapwood part has no current use because although it was conventionally used for wild floorboards, its demand has been replaced by plywood. As mentioned above, since the heartwood part of coniferous trees such as Cryptomeria is a biological material, it has a cell structure that prevents the intrusion of foreign substances from the outside. The sapwood part, which is carrying out the life activities of the tree, has a structure suitable for moving water from the ground to the leaves, and in the wood of the sapwood part, the aqueous solution of the chemical agent easily moves in the fiber direction. Specifically, for Cryptomeria, except for the sapwood part, in normal vacuum-pressure injection, the aqueous solution chemical agent only infiltrates 50 mm or less in the fiber direction and less than 5 mm in the direction perpendicular to the fiber. On the other hand, in the sapwood part of Cryptomeria, it has been confirmed in the preliminary tests of the inventor that in normal vacuum-pressure injection, the aqueous solution chemical agent infiltrates 100 mm or more in the fiber direction and 5 mm or more in the direction perpendicular to the fiber.

[0014] (Previous Invention and Patent Application) Based on this finding, the inventor completed the invention of fire-resistant wood materials such as semi-incombustible or flame-retardant wood and filed a patent application on December 3, 2018, under Japanese Patent Application No. 2018-226298, which was published as Patent Document 6. The invention related to this Patent Document 6 aims to provide semi-incombustible or flame-retardant wood that can exhibit uniform fire-resistant performance and its manufacturing method, and aims to provide semi-incombustible or flame-retardant wood using only the sapwood part of coniferous trees such as Cryptomeria and diffuse-porous hardwoods. At that time, slits of a predetermined depth are formed in the wood at appropriate intervals, and the wood pieces are laminated with an adhesive with the overlapping surface facing inward. By subjecting the laminated material processed in this way to vacuum-pressure injection of a non-combustible chemical agent such as water-soluble, it was intended to provide semi-incombustible or flame-retardant wood with almost uniform and stable non-combustibility throughout.

[0015] The semi-noncombustible or flame-retardant wood according to this Patent Document 6 is a laminated material of the sapwood part of a Japanese cedar board with a thickness of 20 mm and is used as a floorboard surface material. Therefore, it has a very good appearance, and the injection holes with a width of 3 mm and a depth of 5 mm on both sides of the laminated surface also have no problem in appearance. And regarding the injection amount of the noncombustible agent, when injecting the amount required for semi-noncombustibility at a concentration of 25% and 140 - 150 kg / m 3 a semi-noncombustible combustion test was conducted on the one injected with the amount required for semi-noncombustibility, and it passed in terms of both the calorific value and the presence or absence of cracks up to the back surface. However, in this invention, since only the sapwood part is used, there is a problem that the raw material wood that can be collected from one tree is limited.

[0016] Also, when perforating as a means to uniformly inject an effective amount of the agent into LVL, the influence of the decrease in the bending Young's modulus due to cross-sectional defects cannot be avoided. In particular, when implemented as a structural material, this influence cannot be ignored, but in any of the prior art documents, there is no disclosure or suggestion regarding this point.

Prior Art Documents

Patent Documents

[0017]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0018] The present invention aims to improve the reliability of the fire resistance performance of structural LVL containing a non-combustible treatment agent for fire-resistant structural wood materials, and also aims to suppress a decrease in the flexural Young's modulus and a decrease in strength. An object of the present invention is to achieve both an improvement in the reliability of the fire resistance performance of structural LVL containing a non-combustible treatment agent for fire-resistant structural wood materials and ease of procurement of raw materials.

Means for Solving the Problems

[0019] As a means for solving the above problems, the present invention provides wood containing a non-combustible treatment agent for fire-resistant wood materials.

[0020] The important points of the present invention in comparison with the above prior art documents are as follows. 1. Based on the finding that although there are differences in the movement of the aqueous solution of the agent depending on the parts such as the sapwood part and the heartwood part of the wood, the movement in the fiber direction is easier than that in the direction perpendicular to the fiber, the injection of the aqueous solution of the agent is attempted by utilizing this. 2. In order to equalize the agent injection, injection holes extending in a direction intersecting the fiber direction are provided to inject a water-soluble agent. 3. In the case of structural LVL in which raw material veneers are laminated in a plurality of layers in the thickness direction of the front and back via an adhesive layer, the adhesive layer hinders the infiltration of the agent in the thickness direction. Injection holes extending through the adhesive layer are provided to inject a water-soluble agent. 4. Provide an array structure of injection holes that can ensure the infiltration of the agent throughout and also ensure the strength of the structural LVL.

[0021] Furthermore, the invention of Patent Document 6 was an invention based on the finding regarding the injection movement of the water-soluble agent in the sapwood part, but the present invention also focuses on the injection movement of the water-soluble agent in the heartwood part and is completed by finding the amount that the agent can surely move in the longitudinal direction. Specifically, the raw material veneer used in the implementation of the present invention is composed of a part of only the sapwood part, a part of only the heartwood part, or a part where the sapwood part and the heartwood part are mixed. The wood provided by the present invention is a structural LVL in which a plurality of these raw material veneers are laminated in the thickness direction of the front and back via an adhesive layer.

[0022] Here, regarding the movement of an aqueous solution such as a water-soluble chemical agent in the sapwood part and the heartwood part, a more detailed explanation is as follows. There are differences between softwoods and hardwoods, as follows. First, in softwoods, in the sapwood part, the membrane pores of the false tracheids are open, so the aqueous solution moves between cells. However, in the heartwood part, the membrane pores of the false tracheids are closed, making it difficult for the aqueous solution to move between cells. On the other hand, in hardwoods, in the sapwood part, since there are no fillings such as tylose in the lumen of the conduits, the movement of the aqueous solution is easy. However, in the heartwood part, since the lumen of the conduits is filled with filling substances such as tylose, this filling substance obstructs the movement of the aqueous solution and makes the movement difficult. Thus, although there are differences between softwoods and hardwoods, there is a difference in the amount of movement of the aqueous solution between the heartwood part and the sapwood part. Therefore, if this is ignored and the heartwood part and the sapwood part are used in combination, the injected water-soluble chemical agent cannot be evenly distributed.

[0023] Regarding this point, in the wood of the structural LVL of the present invention, by arranging and laminating the raw material veneers so that the fiber direction and the length direction of the internal cracks substantially coincide with the longitudinal direction of the LVL, the difference in the amount of movement can be reduced. That is, in the present invention, the difference in the amount of movement of the non-combustible treatment chemical agent in the longitudinal direction of the LVL between the heartwood part and the sapwood part can be reduced by the following mechanism. Specifically, first, in the wood, since the cell states are significantly different between the sapwood part and the heartwood part as described above, in the sapwood part, the aqueous chemical agent solution can move at least about 10 cm, and in some cases about 30 cm, in the fiber direction by vacuum-pressure injection. On the other hand, in the heartwood part, the intercellular movement of the aqueous chemical agent solution is practically impossible, and the aqueous chemical agent solution hardly moves in the fiber direction. Second, in the rotary veneer, the state of splitting on the back side is significantly different between the sapwood part and the heartwood part. The rotary veneer is a thin veneer obtained by relatively rotating and moving a round log-shaped raw wood and a cutting tool arranged along the axial direction of its outer periphery by a rotary lathe, and slicing thinly and continuously from the outer periphery of the wood. This rotary veneer has a circular arc-shaped cross-section at the sliced stage, but becomes a flat plate with a linear cross-section at the laminated stage, so splitting occurs on the back side according to the radius of curvature. This splitting occurs largely (deeply) and in large numbers as the radius of curvature decreases. As a result, the rotary veneer obtained from the heartwood part closer to the center of the wood has larger (deeper) and more numerous splits on the back side than the rotary veneer obtained from the sapwood part closer to the outer periphery, and these splits serve as passageways for liquids.

[0024] Therefore, by laminating the rotary veneers with the direction in which the splits extend substantially coinciding with the fiber direction of the wood, in the sapwood part where the splits are relatively small and few, mainly the cell lumens and open pits allow the water-soluble non-combustible treatment agent to move, and in the heartwood part where the cell pits are closed, the water-soluble non-combustible treatment agent moves through the relatively large and numerous splits as passageways. As a result, the difference in the amount of movement of the water-soluble non-combustible treatment agent in the length direction of the LVL between the heartwood part and the sapwood part could be reduced.

[0025] The wood of the present invention is provided with injection holes having a circular cross-section extending from the front and back surfaces of the LVL toward the center in the thickness direction, and the injection holes can be easily and efficiently formed by drilling or the like. The injection holes penetrate through the raw veneers and the adhesive layers between the raw veneers. Each of the injection holes on the front and back surfaces is arranged in a plurality at intervals in the width direction and the length direction of the LVL. Among the injection holes, the injection holes from the front surface and the injection holes from the back surface are arranged at different positions in the width direction and the length direction. All of the raw veneers are provided with the injection holes by at least one of the injection holes from the front surface and the injection holes from the back surface.

[0026] For the wood in which the injection holes are formed, a non-combustible agent such as a water-soluble agent is injected under reduced pressure and increased pressure. As a result, the agent is injected into the front and back surfaces of the wood at a depth of about 5 mm via the cracks inclined from the grain surface. Also, the agent penetrates into the center of the wood from the injection holes. In the heartwood part, it mainly penetrates via the cracks, and in the sapwood part, it penetrates well through the cell lumens and the pores of the opened cells, and is injected into the whole by good fluid movement.

[0027] Next, consider the movement of the non-combustible treatment agent in the width direction of the wood (structural LVL). There is almost no movement of the aqueous agent solution across the cell wall of the wood (in other words, across the fiber direction). On the other hand, although it is known that the fiber direction of the tree extends substantially in the vertical direction, in order to maintain its strength, the fibers do not extend in the vertical direction, but extend upward in a spiral like a tornado with an inclination of about one-tenth of the length direction. For this reason, in the sapwood part, in the process where the injected agent infiltrates from the cut surface of the fiber and infiltrates deep into the length direction along the fiber direction, as a result, about one-tenth moves in the direction perpendicular to the fiber. Also, in the heartwood part, since the cracks occur along the fiber direction, in the process where the injected agent infiltrates deep into the length direction using the cracks as a passage, as a result, about one-tenth moves in the direction perpendicular to the fiber. As a result, even if there is almost no movement of the aqueous agent solution across the cell wall of the wood (in other words, across the fiber direction), if injection holes are formed at predetermined intervals without forming injection holes in all directions perpendicular to the fiber, the non-combustible treatment agent can be distributed to such an extent that the desired non-combustibility can be exhibited. The interval W1 between the injection holes in the direction perpendicular to the fiber can be implemented as 25 to 60 mm. Also, the ratio of the interval L1 between the injection holes in the fiber direction to the interval W1 between the injection holes in the direction perpendicular to the fiber can be implemented as about 4 to 1 to 12 to 1, preferably 7 to 1 to 10 to 1.

[0028] In the wood according to the present invention, since the injection holes from the back surface of the wood penetrate the raw material veneer and the adhesive layer between the raw material veneers, an infiltration region in which the non-combustible treatment agent infiltrates in the width direction and the length direction from each of the injection holes is formed in the raw material veneer around the injection holes from the surface. Similarly, since the injection holes from the back surface of the wood penetrate the raw material veneer and the adhesive layer between the raw material veneers, the infiltration regions are formed in all the raw material veneers through which the injection ports penetrate. The infiltration regions are arranged on the front surface side and the back surface side of the wood in the width direction and the length direction, respectively. A three-dimensional infiltration region having a predetermined width, a predetermined length, and a predetermined thickness is formed centering on each of the injection holes from the front surface and the injection holes from the back surface. It is preferable that the respective infiltration regions are formed to overlap each other so that no portion where the non-combustible treatment agent does not infiltrate remains between the adjacent infiltration regions. The injection holes from the front surface and the injection holes from the back surface can be implemented such that their tips overlap in the thickness direction. Therefore, the infiltration regions on the front surface side and the back surface side overlap each other in the vertical direction so that no portion where the non-combustible treatment agent does not infiltrate remains between the infiltration regions in the thickness direction. As a result, in the wood according to the present invention, the non-combustible treatment agent infiltrates into all parts, and fire resistance can be imparted to the entire wood.

[0029] The wood containing the non-combustible treatment agent can be implemented as a structural LVL (Laminated Veneer Lumber, i.e., "veneer laminated lumber") obtained by laminating raw material veneers obtained from either softwood or diffuse-porous hardwood via an adhesive, and mainly used as a load-bearing member of a structure.

[0030] Each of the injection holes from the front surface and the injection holes from the back surface can be implemented as being arranged at equal intervals in both the length direction and the width direction of the LVL. The injection holes in each adjacent row in the length direction of the LVL are arranged at different positions in the width direction, and the injection holes in each adjacent column in the width direction of the LVL are arranged at different positions in the length direction. For example, with respect to the injection holes from the front surface, the injection holes in each adjacent row and each row are shifted by half a pitch in the width direction and the length direction, so that these injection holes are arranged in a staggered pattern when viewed from the front surface side. Also, with respect to the injection holes from the back surface, they are similarly arranged in a staggered pattern when viewed from the back surface side. Then, the injection holes from the front surface and the injection holes from the back surface are arranged with a shift of half a pitch in the width direction and the length direction, so that they are arranged in a checkerboard pattern when viewed from the front and back surfaces.

[0031] When the inventor of the present application conducted a preliminary test on a sawn product of 12 mm × 110 mm × 1100 mm, it was confirmed that when the perforation interval in each stage was 50 mm, the bending Young's modulus decreased by 15% - 20%, and when the perforation interval was 200 mm, the bending Young's modulus decreased by 3% - 7%. From the above, it was confirmed that the longer the perforation interval, the smaller the decrease in the bending Young's modulus. Although it depends on the tree species, the perforation interval in the length direction is preferably 150 mm - 200 mm for a mixed sapwood and heartwood single - veneer Japanese cedar LVL, and 100 mm - 150 mm for a mixed sapwood and heartwood single - veneer poplar LVL. Thus, it is possible to provide wood that can achieve uniform injection of the non - combustible treatment agent and suppress the influence of the decrease in the bending Young's modulus due to cross - sectional defects.

Advantages of the Invention

[0032] The present invention can improve the reliability of the fire - resistant performance and suppress the decrease in the bending Young's modulus and the strength decrease for a structural LVL containing a non - combustible treatment agent for a woody material for a fire - resistant structure. The present invention can achieve both an improvement in the reliability of the fire - resistant performance and the ease of procurement of raw materials for a structural LVL containing a non - combustible treatment agent for a woody material for a fire - resistant structure. The embodiments of the present invention can bring about the following advantages. · The processing cost can be reduced by reducing the number of production processes. · Since it can be carried out without sorting the wood parts to be used, the yield is improved. ·It is possible to achieve uniform injection of the non-combustible treatment agent and suppress the influence of the reduction in the flexural Young's modulus due to cross-sectional defects.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0034] Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Overview) The wood containing the non-combustible treatment agent for the fire-resistant structural wood material according to this embodiment is the structural LVL61 in which a plurality of raw material veneers 51 are laminated via an adhesive layer. As shown in Fig. 1(A), the raw veneer 51 may be a mixture of the sapwood part A, white line zone B, mature heartwood part C, and immature heartwood part D of coniferous trees such as cedar or diffuse-porous hardwoods, or as shown in Fig. 1(B), it may be composed only of the sapwood part A of coniferous trees such as cedar or diffuse-porous hardwoods. The raw veneers 51 are all arranged so that their fibers extend along the longitudinal direction (arrow direction) of the structural LVL 61 shown in Figs. 2 and 3.

[0035] (Manufacture of Structural LVL 61) Generally, wood is often roughly classified into a sapwood part and a heartwood part. The sapwood part refers to the lighter-colored outer part in the cross-section of a log, and the heartwood part refers to the reddish-colored central part in the cross-section of a log. More specifically, the heartwood part can be further divided into two regions: an immature part and a mature part in the central part, and there may also be a white line zone in the boundary region between the sapwood part and the heartwood part. Therefore, as shown in Fig. 1, it can be divided into four regions: the sapwood part A, white line zone B, mature heartwood part C, and immature heartwood part D from the outside. In the present invention, when simply referring to the heartwood part, it shall indicate a part including the white line zone B, mature heartwood part C, and immature heartwood part D.

[0036] In the present invention, as shown in Fig. 1(A), not only the sapwood part A with good fluid movement but also the heartwood part with relatively poor fluid movement can be used, or a mixture of these may be used. However, as shown in Fig. 1(B), it may also be made using only the sapwood part A where fluid movement occurs well in the direction of fiber extension inside the wood.

[0037] (Regarding the Raw Veneer 51) The raw veneer 51 is obtained from these parts. The raw veneer 51 is arranged with the fiber extension direction (longitudinal direction of the standing tree) as the longitudinal direction and laminated to manufacture the structural LVL 61. The raw material veneer 51 is manufactured by cutting a standing tree used as a raw material into a predetermined thickness using a rotary lathe capable of causing internal splitting. At this time, in Fig. 1(B), it is necessary to distinguish only the sapwood part A from the remaining white line band B, the heartwood part aging part C, and the heartwood part unaged part D from the sapwood part A, but in Fig. 1(A), there is no need to distinguish, which is advantageous in terms of material extraction. The raw material veneer 51 is processed into the structural LVL 61 of specified dimensions through processes such as cutting, drying, adhesion, lamination, and cutting, and these processes can be carried out in the same manner as the normal LVL manufacturing process. Also, since the structural LVL 61 generally has a large thickness and a large cross-section, adhesion and lamination can be repeated multiple times. For example, when obtaining a structural LVL 61 with a thickness of about 100 mm using raw material veneers with a thickness of about 2 to 4 mm (in some cases, 1 mm or less), about 25 to 100 or more raw material veneers are laminated. Instead of laminating the desired number of raw material veneers at once, the lamination thickness can be set to 50 mm in the first lamination, and these can be adhered in the second lamination to manufacture a structural LVL 61 with a thickness of 100 mm.

[0038] Note that since Figs. 2 and 4 are for explaining the structure, the raw material veneer 51 is drawn with a larger thickness and fewer pieces than in reality. As understood from the above description, in reality, a large number of thin raw material veneers 51 are laminated and implemented. Also, this structural LVL 61 may be a consolidated laminate compressed in the thickness direction. This structural LVL 61 is formed by laminating a plurality of raw material veneers 51 in the thickness direction (T). Width (W): 45 - 900 mm Thickness (T): 30 - 210 mm Length (L): 1800 - 9000 mm It can be implemented with, and at least one of the upper and lower injection holes 62 is formed in the raw material veneer 51 and the adhesive between them.

[0039] (Regarding the injection hole 62) A large number of injection holes 62 are formed in the structural LVL 61 laminated with the raw material veneer 51. In the following description, the thickness direction of the laminate of the raw material veneer 51 will be described as (T), the width direction as (W), and the length direction as (L). As shown in FIGS. 2(A), 2(B), and 3, a large number of injection holes are formed by drilling on the grain surfaces of the front and back of the structural LVL 61 (the front grain surface 11 and the back grain surface 21). On the premise that the chemical liquid such as the non-combustible treatment agent 31 mainly moves fluidly in the fiber direction, injection holes 62 having a substantially circular cross-section extending in a direction crossing the fibers of the structural LVL 61 are formed with a drilling tool such as a drill. The diameter of the injection hole 62 can be made larger for deeper drilling, but as it is made larger, mechanical properties such as strength and flexural Young's modulus decrease, so it is determined considering the drilling depth, and generally it is preferably about 3 to 15 mm.

[0040] This injection hole 62 is a hole having a circular cross-section extending from the grain surfaces of the front and back in the thickness (T) direction, and can be implemented as having a depth of at least half of the plate thickness. The injection holes 62 (the upper injection hole 62(U) from the front surface and the lower injection hole 62(D) from the back surface) are arranged in a plurality of rows on the grain surfaces of the front and back (the front grain surface 11 and the back grain surface 21), and a plurality of them are arranged in the width direction (W) in each row. For example, when the cross-sectional dimensions of the LVL are 150 mm × 150 mm, the upper injection hole 62(U) and the lower injection hole 62(D) can be implemented with a hole diameter of about 3 to 15 mm (preferably 5 mm to 10 mm) and a depth of 75 mm. Note that the depth of the injection hole 62 may exceed 75 mm in consideration of variations during processing. In short, it is sufficient that either the upper injection hole 62(U) or the lower injection hole 62(D) of the injection hole 62 reaches all the raw material veneers 51, and the lengths of the upper injection hole 62(U) and the lower injection hole 62(D) may be different.

[0041] (Arrangement form of injection holes 62) As shown in FIG. 3, the front and back injection holes 62 (upper injection hole 62(U) and lower injection hole 62(D)) have an interval in the fiber direction (length direction = L) of, for example, L1 = 200 to 300 mm in each column in the case of LVL mixed with sugi sapwood part, and an interval between each column in the direction orthogonal to the fiber (width direction = W) of W1 = 30 to 60 mm. These intervals can be changed and implemented, The interval L1 between the injection holes in the fiber direction is 100 to 300 mm The interval W1 between the injection holes in the direction orthogonal to the fiber is 25 to 60 mm and it is preferable to set it like this.

[0042] In this embodiment, in each column adjacent in the length direction L on the front and back surfaces, the interval in the fiber direction (length direction = L) of the injection holes 62 is shifted by a half pitch (W1 / 2 = 10 mm in this example). Further, in each row adjacent in the width direction W on the front and back surfaces, the interval in the fiber direction (length direction = L) of the injection holes 62 is shifted by a half pitch (L1 / 2 = 100 mm in this example). As a result, in each of the front side and the back side of this structural LVL61, each injection hole 62 (upper injection hole 62(U) and lower injection hole 62(D)) is arranged in a staggered pattern.

[0043] Also, the arrangement of the upper injection hole 62(U) from the front surface and the lower injection hole 62(D) from the back surface is arranged in a checkerboard pattern by being shifted by a half pitch in the length direction (L) and the width direction (W). That is, the upper injection hole 62(U) from the front surface and the lower injection hole 62(D) from the back surface have an interval in the fiber direction (interval in the length direction (L)) of L2 = 100 mm. The interval between each column in the direction orthogonal to the fiber (interval in the width direction (W)) is W2 = 10 mm. Note that the interval between each column in the above direction orthogonal to the fiber (width direction = W) is the distance between the centers of adjacent holes.

[0044] When injecting a chemical agent into a bonded wood material such as LVL or laminated wood, the adhesive layer formed by the solidification of the adhesive between the raw veneers becomes a wall, preventing the infiltration of the chemical aqueous solution. Therefore, although infiltration of the aqueous solution in the direction of the board grain (W) perpendicular to the fibers is possible, infiltration in the lamination direction is hindered by the wall of the solidified adhesive, making infiltration more than the veneer thickness difficult. Therefore, in order to inject the chemical agent evenly inside the LVL, it is necessary to inject through the injection holes formed in the lamination direction penetrating the veneers and the adhesive layer from the board grain surface and infiltrate in the fiber direction.

[0045] The interval between the injection holes 62 should be determined based on the type of wood material, the difference between the sapwood part and the heartwood part, the type of tree, and the regional difference in growth, etc., and it is appropriate to determine a distance with sufficient margin for infiltration in a preliminary test of dye solution injection. Drilling can easily form injection holes 62 with a substantially circular cross-section, and injection holes 62 with a substantially circular cross-section are advantageous in that they can evenly disperse the external load compared to openings with a polygonal cross-section.

[0046] (Other arrangement forms) As shown in Fig. 7, the arrangement form of the upper injection holes from the surface can be made into a checkerboard pattern, and the arrangement form of the lower injection holes from the back surface can be made into a checkerboard pattern, and by shifting the arrangement of these front and back injection holes by half a pitch, it can also be made into a staggered pattern as a whole. However, in this case, when looking at each of the front side and the back side, since the positions of the injection holes in each row and each column in the width direction and the length direction coincide, the arrangement form shown in Fig. 3 is more advantageous from the viewpoint of suppressing the deterioration of mechanical performance.

[0047] (Injection of chemical agent) The injection process of the chemical agent is a process of injecting a non-combustible treatment chemical agent into the structural LVL61. Specifically, for the structural LVL61, using a vacuum-pressure injection tank, a wood product injected with an aqueous solution of a non-combustible, semi-non-combustible, or flame-retardant treatment chemical agent is completed. The injection amount of the chemical agent may be set according to the board thickness of the raw veneer 51 of the structural LVL61, the type of tree, and the regional difference in growth. However, as a guideline for Japanese cedar, for a structural LVL61 with a thickness of 150 mm, it is about 150 kg / m 3 It is appropriate to do so.

[0048] Unlike sawn timber products and glued laminated timber, there is no significant difference in plywood, but depending on the tree species and growth conditions, the impregnation state of the chemical solution changes. Therefore, it is preferable to confirm and carry out the reduced pressure conditions and time, the pressurization conditions and time, and the number of repetitions through preliminary experiments using a water-soluble coloring agent. Also, in terms of process control, it is preferable to measure the weight before and after injection and manage the difference as the average injection amount per lot.

[0049] The non-combustible treatment chemical 31 that has entered the injection hole 62 through the opening provided on the surface and back grain surfaces of the veneer moves fluidly in the fiber direction, thereby enabling the non-combustible treatment chemical 31 to infiltrate the central part of the thickness of the structural LVL 61. When it is composed only of the heartwood part, as described above, in softwood, the cell membrane pores are closed, and in hardwood, the tylose and other fillers are filled, so fluid movement through the cells is difficult. However, since the back cracks of the rotary veneer are relatively large and occur in large numbers, the chemical infiltrates through the back cracks of the rotary veneer as a passage. Therefore, if the injection holes 62 are provided at intervals of 100 to 300 mm in the length direction, it has been confirmed by the research of the inventors of the present application that the non-combustible treatment chemical 31 can be infiltrated almost uniformly. On the other hand, when it is composed only of the sapwood part, the back cracks of the rotary veneer are relatively small and the number of occurrences is also small. However, in softwood, the cell membrane pores are open, and in hardwood, there are no fillers such as tylose, so fluid movement through the membrane pores and cell lumens is likely to occur. Therefore, since the chemical infiltrates through the membrane pores and cell lumens as a passage, if the injection holes 2 are provided at the above intervals, it has been confirmed by the research of the inventors of the present application that the non-combustible treatment chemical 31 can be infiltrated almost uniformly. Therefore, by making the longitudinal direction of all the raw veneers 51 constituting the structural LVL 61 substantially coincide with the fiber direction and the length direction of the back cracks, whether it is composed only of the sapwood part, only of the heartwood part, or a mixture of the heartwood part and the sapwood part, if the injection holes 62 are provided at intervals of 100 to 300 mm in the length direction, the non-combustible treatment chemical 31 can be infiltrated almost uniformly.

[0050] As shown in Fig. 4, the depth inside the injection holes 62 of the structural LVL 61 is preferably set to a length of at least half of the width in the width direction so that the intervals are not opened in the left - right width direction, and preferably, a part thereof overlaps. Further, as shown in Figs. 3 and 5, in the plan view of the structural LVL 61, from the viewpoint of maintaining the strength of the finished wood, it is preferable that the injection holes 62 are provided in a staggered pattern alternately left and right at positions where they do not overlap on each of the front - side and back - side surfaces. More preferably, as shown in Fig. 3, on each of the front - side and back - side surfaces, the injection holes 62 are provided in a checkerboard pattern alternately left and right.

[0051] As shown in Figs. 5 and 6, the non - combustible treatment agent 31 is introduced and infiltrated into the structural LVL 61 from the upper injection holes 62(U) on its surface. By this, on each veneer laminated around the upper injection holes 62(U), an infiltration region 31 on the front - side surface where the non - combustible treatment agent infiltrates in the width direction and the length direction from each of the injection holes is formed. The infiltration region 31 on the front - side surface is arranged on the front - side surface of the wood in the width direction and the length direction, and is arranged so as to overlap each other so that there is no portion where the non - combustible treatment agent has not infiltrated between adjacent infiltration regions 31. Similarly, on each veneer around the lower injection holes 62(D) from the back surface, an infiltration region 41 on the back - side surface where the non - combustible treatment agent infiltrates in the width direction and the length direction from each of the lower injection holes 62(D) is formed. The infiltration region 41 on the back - side surface is arranged on the back - side surface of the wood in the width direction and the length direction, and is arranged so as to overlap each other so that there is no portion where the non - combustible treatment agent has not infiltrated between adjacent infiltration regions 41. The infiltration region 31 on the front - side surface and the infiltration region 41 on the back - side surface are arranged so as to overlap each other so that there is no portion where the non - combustible treatment agent has not infiltrated between the infiltration regions in the thickness direction. As a result, the entire region of the wood becomes an infiltration region of the non - combustible treatment agent.

[0052] (Steps after injection) Curing: It is preferable to perform curing for the leveling of the injection agent inside the wood, and the curing period is determined by preliminary experiments. Drying: In order to meet the quality as a product determined by an agreement with the customer, etc., the moisture content is controlled. It is preferable to perform artificial drying for quality improvement.

[0053] Finishing process: In order to meet the predetermined conditions as a product, finishing processes such as sizing with a lip saw or band saw, length with a crosscut saw, and surface with a sander or planer are performed. Inspection: Perform inspections necessary to meet the quality as a product. For example, measure the thickness and width with a caliper or a steel tape measure, measure the length with a steel tape measure, and confirm the appearance and surface properties by visual inspection and touch. Packaging: The product is subjected to necessary packaging such as covering all six sides to block moisture from the outside air, or covering it with kraft paper and fixing it with tape so as not to be damaged.

[0054] The wood according to this embodiment can exhibit substantially uniform and good fire resistance performance as the entire fire-retardant modified wood material. When a wood material with an insufficient part of chemical injection is heated, when it reaches a high temperature range of 200 °C or more, combustible gas is generated from the wood tissue of the insufficient part, and the gas ignites. As a result, its fire resistance performance is greatly impaired. However, since the wood of the present invention is impregnated with a sufficient amount of fire-resistant chemical substantially throughout, the generation of combustible gas from the wood tissue is suppressed, and air is blocked by the carbonized layer of the chemical formed on the wood surface, so that stable fire resistance performance can be shown.

Example

[0055] Examples are shown below to enhance the understanding of the present invention, but the present invention should not be understood as being limited to these examples.

[0056] Example 1 Species of raw veneer: Japanese cypress Thickness of raw veneer: 3 mm The above raw veneers were laminated via a water-soluble adhesive to create LVL for structures with the following dimensions. The number of samples was 30 (Examples 1-1 to 1-30). Width of LVL for structures: 90 mm Thickness of structural LVL: 45 mm Length of structural LVL: 1200 mm

[0057] For the obtained "before processing" structural LVL, injection holes were formed from the front board surface and the back board surface in the form shown in Fig. 3 under the following conditions respectively to obtain the "after processing" structural LVL. w1: 60 mm L1: 200 mm Length in the thickness direction (depth): 25 mm Diameter: 5 mm

[0058] Example 2 Species of raw veneer: Poplar Thickness of raw veneer: 2 mm The above raw veneers were laminated through a water-soluble adhesive to create a structural LVL with the following dimensions. The number of samples was 30 (Examples 2-1 to 2-30). Width of structural LVL: 110 mm Thickness of structural LVL: 40 mm Length of structural LVL: 1200 mm

[0059] For the obtained "before processing" structural LVL, injection holes were formed from the front board surface and the back board surface in the form shown in Fig. 3 under the following conditions respectively to obtain the "after processing" structural LVL. W1: 60 mm L1: 200 mm Length in the thickness direction (depth): 20 mm Diameter: 5 mm

[0060] The following bending tests were conducted on the "before processing" and "after processing" structural LVLs of Example 1 and Example 2, and the obtained bending Young's moduli are shown in Table 1. The tests were carried out in accordance with the test method of Japanese Agricultural Standard JAS 0701-1 Bending Test 4.9 in the following manner.

[0061] Bending test The test measured the upper limit load and lower limit load in the proportional range, the corresponding deflections, and the maximum load under the conditions of relevant temperature and humidity, and calculated the flexural Young's modulus based on the measurement results.

[0062] For each of Example 1 (1-1 to 1-30) and Example 2 (2-1 to 2-30), Table 1 shows the flexural Young's modulus "before processing", the flexural Young's modulus "after processing", and the ratio of the two. Table 2 shows the maximum value (max), minimum value (min), average value (ave), standard deviation (σ), lower limit specification (ave - 3σ) of 30 pieces of data, and the ratio of the average value "before processing" to the average value "after processing".

[0063]

Table 1

[0064]

Table 2

[0065] As is clear from the results of Table 1 and Table 2, the change in the flexural Young's modulus between "before processing" and "after processing" stopped at around 0.95, and it was possible to suppress the influence of the decrease in the flexural Young's modulus due to cross-sectional defects. It was confirmed that appropriate quality control could be carried out after setting the lower limit specification. Also, as described above, in this structural LVL, since the non-combustible treatment agent injected from the injection hole 62 is uniformly present, it exhibits a predetermined non-combustible performance. Therefore, it was possible to provide a structural LVL that achieved both uniform injection of the non-combustible treatment agent and suppression of the influence of the decrease in the flexural Young's modulus due to cross-sectional defects.

Explanation of Signs

[0066] 11... Front side board surface 21... Back side board surface 31... Infiltration area on the front surface side 41... Infiltration area on the back surface side 51... Raw material veneer 61... Structural LVL 62... Injection hole 62(U) … Upper injection hole 62(D) … Lower injection hole A … Sapwood part B … White line band C … Heartwood part aging part D … Heartwood part unaged part

Claims

1. In wood into which a non-combustible treatment agent has been injected, the wood is a structural LVL in which raw material veneers each composed of only a sapwood part, only a heartwood part, or a part where the sapwood part and the heartwood part are mixed are laminated in plurality in the thickness direction of the front and back via an adhesive layer, the raw material veneers are rotary veneers having internal cracks, the longitudinal direction of the wood substantially coincides with the fiber direction and the length direction of the internal cracks, the wood has injection holes each having a circular cross-section extending in the thickness direction from each of the front and back surfaces of the LVL, the injection holes penetrate through the plurality of raw material veneers and the adhesive layer between the raw material veneers, each of the injection holes on the front and back surfaces is arranged in plurality at intervals in the width direction and the length direction of the LVL, among the injection holes, the injection holes from the front surface and the injection holes from the back surface are arranged at different positions in the width direction and the length direction, All of the raw material veneers are provided with the injection holes by at least one of the injection holes from the front surface and the injection holes from the back surface, and the wood contains a non-combustible treatment agent.

2. Each of the injection holes from the front surface and the injection holes from the back surface are arranged at equal intervals in both the length direction and the width direction of the LVL, the injection holes in each adjacent row in the length direction of the LVL are arranged at different positions in the width direction, the injection holes in each adjacent row in the width direction of the LVL are arranged at different positions in the length direction, The wood according to claim 1, wherein the tips of the injection holes from the front surface and the injection holes from the back surface overlap in the thickness direction.

3. The raw material veneer around the injection hole from the front surface is provided with an infiltration region on the front surface side where the non-combustible treatment agent has infiltrated in the width direction and the length direction from each of the injection holes, the infiltration region on the front surface side is arranged on the front surface side of the wood in the width direction and the length direction, and is arranged to overlap with each other so that there is no portion where the non-combustible treatment agent has not infiltrated between the adjacent infiltration regions, The raw material veneer around the injection hole from the back surface is provided with an infiltration region on the back surface side where the non-combustible treatment agent has infiltrated in the width direction and the length direction from each of the injection holes, The infiltration regions on the back side are arranged on the back side of the wood in the width direction and the length direction, and are arranged so as to overlap each other so that no portion where the non-combustible treatment agent has not infiltrated remains between adjacent infiltration regions. The infiltration region on the front side and the infiltration region on the back side are configured to be arranged so as to overlap each other so that no portion where the non-combustible treatment agent has not infiltrated remains between the infiltration regions in the thickness direction. The wood according to claim 1 or 2, characterized in that.

4. The wood is Width (W): 45 to 900 mm Thickness (T): 30 to 210 mm Length (L): 1800 to 9000 mm The wood containing a non-combustible treatment agent according to claim 1 or 2, characterized in that.

5. The injection holes are Diameter of the injection hole: 3 to 15 mm Interval L1 between injection holes in the fiber direction = 100 to 300 mm Interval W1 between injection holes in the direction perpendicular to the fiber = 25 to 60 mm Ratio of the interval L1 between injection holes in the fiber direction to the interval W1 between injection holes in the direction perpendicular to the fiber = 4 to 1 to 12 to 1 The wood containing a non-combustible treatment agent according to claim 1 or 2, characterized in that.

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