Glulam

Abstract

This suppresses delamination at joints in laminated timber, which is composed of different types of boards. [Solution] A laminated timber L1 in which two boards 1 and 2 are joined in the thickness direction with a bonding agent 3, wherein one board 1 to be joined has a plurality of protrusions on the joining surface, and the other board 2 has a plurality of recesses on the joining surface into which the plurality of protrusions fit, and the difference in total dry specific gravity between the one board 1 and the other board 2 to be joined is 0.1 g / cm³. 3 That's all.

Description

[Technical Field]

[0001] This invention relates to laminated timber in which two or more boards are joined together in the thickness direction. [Background technology]

[0002] Laminated timber, made by bonding two or more boards together with adhesive in the thickness direction, has the advantage of uniform strength and resistance to deformation compared to natural wood, allowing for stable use even with large cross-sections and long lengths. Furthermore, since laminated timber can be manufactured after removing defects such as knots and cracks from natural wood, uniform quality and high processing precision can be expected. In addition, laminated timber allows for the effective use of small-diameter trees and offcuts, enabling the efficient use of forest resources. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2015-71252 [Patent Document 2] Japanese Patent Publication No. 2007-268731 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, as shown in Figure 6(a), in the case of laminated timber L4 in which a board 8 with a high specific gravity and a board 9 with a low specific gravity are joined with a bonding agent 3, generally, the lower the specific gravity of the wood, the greater the shrinkage rate. Therefore, as shown in Figure 6(b), the board 9 with the low specific gravity may shrink and deform, causing a defect in which the joint between board 8 and board 9 may peel off.

[0005] This invention has been made in view of the above-mentioned conventional problems, and aims to suppress delamination at joints in laminated timber composed of different types of board material. [Means for solving the problem]

[0006] To achieve the above objective, a laminated timber according to one aspect of the present invention is a laminated timber in which two or more boards are joined together in the thickness direction with a bonding agent, wherein one of the boards to be joined has a plurality of protrusions on the joining surface, and the other board has a plurality of recesses on the joining surface into which the plurality of protrusions fit, and the difference in total dry specific gravity between one board and the other board is 0.1 g / cm³. 3 The above is the characteristic feature.

[0007] In this specification, "dry specific gravity" refers to the specific gravity of wood after all the water inside the cell walls has been removed. Specifically, it is a value measured by the following method: A test specimen cut to a predetermined size is dried in a well-ventilated dryer at a temperature of 100-105°C in accordance with JIS Z2102 until a constant weight is reached, and the dry weight (W) is measured. The volume (V) of the same dried test specimen is also measured, and the dry specific gravity is determined from the ratio of the two, W / V. The weight of dried wood will be approximately the same for the same tree species.

[0008] In the laminated timber having the above configuration, it is preferable that at least one of the boards to be joined has been subjected to one of the following treatments: acetylation, kebony treatment, thermo treatment, or flanwood treatment.

[0009] Furthermore, in the laminated timber having the above configuration, it is preferable that the shape of the cross-section perpendicular to the direction of extension of the convex and concave ridges is at least one of polygonal, arc-shaped, or corrugated.

[0010] Furthermore, in the laminated timber having the above configuration, it is preferable that the height of the protrusions is 5 mm or less.

[0011] Furthermore, in the laminated wood having the above configuration, it is preferable that the spacing between the protrusions is in the range of 5 mm to 15 mm.

[0012] Furthermore, in the laminated timber having the above configuration, it is preferable that the spacing between the protrusions is the same as or twice the maximum width of the cross-section perpendicular to the direction in which the protrusions extend.

[0013] Further, in the glued laminated timber having the above configuration, the bonding agent is preferably at least one of polyurethane resin, aqueous polymer-isocyanate, epoxy resin, and resorcinol resin.

[0014] A frame body according to one aspect of the present invention is a frame body, a part of which is exposed to the outdoors, using the glued laminated timber according to any one of the above, wherein the glued laminated timber is used such that a plate material having a high absolutely dry specific gravity is positioned on the outdoor side and a plate material having a low absolutely dry specific gravity is positioned on the indoor side.

[0015] In the frame body having the above configuration, the frame body may be at least one of a window frame and a door frame.

Effects of the Invention

[0016] According to the glued laminated timber of the present invention, peeling or the like of the bonding surface is suppressed even when the glued laminated timber is composed of different types of plate materials.

[0017] According to the frame body of the present invention, peeling or the like of the bonded portion is suppressed even when a part of the frame body is exposed to the outdoors, and the frame body can be used over a long period of time.

Brief Description of Drawings

[0018] [Figure 1] It is a vertical cross-sectional view showing one embodiment of the glued laminated timber according to the present invention. [Figure 2] It is a cross-sectional perspective view of the glued laminated timber of FIG. 1. [Figure 3] It is an example vertical cross-sectional view showing other shapes of the protruding strip and the recessed strip of the glued laminated timber according to the present invention. [Figure 4] It is a vertical cross-sectional view showing one embodiment of the frame body according to the present invention. [Figure 5] It is a vertical cross-sectional view showing the structure of glued laminated timbers of Examples and Comparative Examples. [Figure 6] It is a vertical cross-sectional view showing a defect of a conventional glued laminated timber.

Mode for Carrying Out the Invention

[0019] Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, the same or corresponding components will be denoted by the same reference numerals, and their descriptions may be omitted as appropriate. In addition, in the following description, "x direction," "y direction," and "thickness direction" refer to the x direction, y direction, and thickness direction shown in each figure.

[0020] (laminated wood) Figure 1 shows a vertical cross-sectional view illustrating one embodiment of the laminated timber according to the present invention. The laminated timber L1 shown in Figure 1 consists of a board 1 and a board 1 with a total dry specific gravity 0.1 g / cm³ higher than that of the board 1. 3 The above-mentioned small plate material 2 is joined in the thickness direction with a bonding agent 3.

[0021] As shown in Figure 2, on the joining surface of one plate material 1, multiple triangular cross-section protrusions 11 extending linearly in the y direction are formed at predetermined intervals p in the x direction. On the joining surface of the other plate material 2, multiple triangular cross-section recesses 21 extending linearly in the y direction are formed at predetermined intervals p in the x direction, into which the protrusions 11 fit.

[0022] Plate material 1 and plate material 2 are joined together by a bonding agent 3, with multiple protrusions 11 and multiple recesses 21 interlocked. Specifically, after the bonding agent 3 is applied to one or both surfaces of the protrusions 11 and recesses 21 of plate material 1 and plate material 2, plate material 1 and plate material 2 are positioned and joined together so that the protrusions 11 and recesses 21 interlock, thereby producing the laminated timber L1. After joining, if necessary, the joints are held in place for a predetermined time with external force applied in the direction of joining until the bonding agent 3 hardens.

[0023] The difference in total dry specific gravity between board material 1 and board material 2 to be joined is 0.1 g / cm³. 3The above points are relevant. Generally, the lower the total dry specific gravity, the greater the shrinkage rate and the easier it is to deform. Therefore, when joining board materials with a large difference in total dry specific gravity, delamination is likely to occur at the joint. In this invention, multiple protrusions 11 and recesses 21 are provided on the joint surface between board material 1 and board material 2 to increase the joining area, and the deformation of board material 1 and board material 2 is physically suppressed by fitting the protrusions 11 and recesses 21 together. Preferably, the increase in contact area due to the provision of protrusions 11 and recesses 21 is 15% or more compared to the case where the protrusions 11 and recesses 21 are not provided.

[0024] Furthermore, the laminated timber according to the present invention is not limited to a product in which two boards are joined together, but may of course be a product in which three boards are joined together. When three or more boards are joined together, the difference in total dry specific gravity shall refer to the difference in total dry specific gravity between two boards joined together by the adhesive 3.

[0025] The height h of the protrusions 11 (depth of the recesses 21) formed on the joint surface of the plate material 1 is related to the spacing p between the protrusions 11, but it is preferable that it be 5 mm or less. Increasing the height h of the protrusions increases the joint area and thus the joint strength, but it also increases the amount of material removed from the plate material 1, resulting in a lower yield.

[0026] The spacing p of the protrusions 11 (recesses 21) formed on the joint surface of the plate material 1 (plate material 2) is preferably in the range of 5 mm to 15 mm. If the spacing p of the protrusions 11 (recesses 21) is less than 5 mm, the amount of material to be cut from the plate material 1 increases, resulting in a poor yield. If the spacing p of the protrusions 11 (recesses 21) is greater than 15 mm, there is a risk of delamination at the joint.

[0027] The cross-sectional shape of the protrusions 11 (recesses 21) formed on the joint surface of the plate material 1 (plate material 2), perpendicular to the direction of extension, may be triangular, or it may be a polygon such as a square, or it may be an arc or wave shape. The tips and corners of the protrusions 11 may be rounded or chamfered from the viewpoint of smooth fitting with the recesses 21.

[0028] As shown in Figure 2, the laminated timber L1 has triangular cross-sections for the ridges 11, and the spacing p between the ridges 11 is the same as the maximum width w of the ridges 11. When the spacing p between the ridges 11 is the same as the maximum width w of the ridges 11, the ridges are formed continuously on the surface of the board material 1.

[0029] The spacing p between the ridges may be twice the maximum width w of the ridges. In Figure 3(a), the laminated timber L2 is an example where the cross-section of the ridges 12 is square and the spacing p between the ridges 12 is twice the maximum width w of the ridges 12. In Figure 3(b), the laminated timber L3 is an example where the cross-section of the ridges 13 is isosceles trapezoidal and the spacing p between the ridges 13 is twice the maximum width w of the ridges 13.

[0030] As shown in Figures 2 and 3, if the spacing p between the protrusions is the same as or twice the maximum width w of the protrusions, the multiple protrusions formed on plate material 1 and the multiple recesses formed on plate material 2 will have a symmetrical shape, making it efficient to form them with a common cutting member.

[0031] The laminated timber used in this invention has a dry specific gravity difference of 0.1 g / cm³. 3 There are no particular limitations on the above combinations; you can select and use any conventionally known board material. Table 1 shows an example of tree species that can be used in this invention and their total dry specific gravity.

[0032] [Table 1]

[0033] The sheet material that can be used in this invention may be one that has undergone any one of the following treatments: acetylation, Kebony treatment, thermo treatment, or Franwood treatment.

[0034] Acetylation is a process in which wood planks are immersed in an acetylating agent (usually acetyl alcohol or acetylacetic acid) to replace hydroxyl groups (-OH) with acetyl groups (-COOCH3). This process seals the cell walls of the wood, preventing the permeation of water and air. Acetylation increases the dry specific gravity of the wood planks. Generally, acetylation increases the dry specific gravity of wood to approximately 0.1 g / cm³. 3 It increases to a certain extent.

[0035] Kevony treatment is a process in which furfuryl alcohol is impregnated into wood and then heated to induce polymerization. Kevony treatment fills the cell walls of the wood with furan resin, increasing density and improving hardness and durability. It also enhances dimensional stability and resistance to decay.

[0036] Thermo-treatment (high-temperature heat treatment) is a process that improves the strength and durability of wood by heating it to a high temperature and then rapidly cooling it. This treatment reduces the moisture content of the wood, increasing its resistance to decay and insect damage. Thermo-treatment also has the effect of changing the color of the wood, improving its aesthetic appeal.

[0037] Franwood treatment involves impregnating wood with furan water derived from plants. This treatment protects the wood from moisture, insect damage, and mold, improving its durability.

[0038] The bonding agent 3 used in the present invention is not particularly limited, and conventionally known bonding agents can be used. For example, one or more of the following can be used as bonding agents 3: polyurethane resin, aqueous polymer-isocyanate, epoxy resin, and resorcinol resin.

[0039] (Frame) The frame according to the present invention is a frame in which a part, such as a window frame or door frame, is exposed to the outdoors, and a major feature of the laminated timber according to the present invention is that the board material with a high total dry specific gravity is used on the outdoor side.

[0040] Generally, wood with a higher dry specific gravity shrinks less. Therefore, using laminated timber with the higher dry specific gravity boards facing the outdoors improves the weather resistance and durability of the frame.

[0041] Figure 4 shows an example of a partial cross-sectional view of a window using the frame according to the present invention. The window WD shown in Figure 4 comprises a window frame (frame body) 4 and a sash 5 that can slide within the window frame 4 in the direction perpendicular to the plane of the paper. The sash 5 has glass 51 and a frame (frame body) 52 attached around the glass 51.

[0042] The window frame 4 is made of laminated timber, which is formed by joining four planks 41-44 of the same tree species with a plank 40 that has a higher total dry specific gravity than plank 44 using a bonding agent 3 (not shown). The laminated timber is then processed into a predetermined shape by cutting or other means, and assembled so that plank 40 is on the outermost side.

[0043] The frame 52 of the shoji screen 5 is made of laminated wood, which is formed by joining two planks 521 and 522 of the same tree species with a plank 520 that has a higher total dry specific gravity than plank 522 using a bonding agent (not shown). This laminated wood is then processed into a predetermined shape by cutting or other means, and assembled so that plank 520 is on the outermost side.

[0044] With a window WD of this structure, even if laminated timber is used for the window frame 4 and stile 52 as the frame, the parts exposed to the outdoors are made of board material 40 and board material 520 with a high total dry specific gravity, and the joint surfaces of board material with different total dry specific gravity have a structure in which multiple convex and concave grooves fit together, so that even when exposed to sunlight and rain for a long period of time, delamination at the joints of the laminated timber is effectively suppressed. Normally, when board material of the same tree species is joined together, delamination at the joints is unlikely to occur. [Examples]

[0045] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to these examples.

[0046] Examples 1-4 A plate of acetylated radiata pine (oven-dry specific gravity: 0.52) and a plate of sugi (Japanese cedar, oven-dry specific gravity: 0.34) were formed with convex strips and concave strips having a triangular cross-section as shown in Figures 5(a) to (d), then the first plate and the second plate were bonded with an aqueous polymer-isocyanate ("KR-134" manufactured by Koyo Sangyo Co., Ltd.) serving as the bonding agent 3 to produce glued laminated timber L a ~L d was produced. Test specimens (x: 40 mm, y: 20 mm, thickness: 40 mm) were cut from the produced glued laminated timber L a ~L d from the produced glued laminated timber L A weather resistance test was performed on the test specimens for 10 cycles, where one cycle consisted of immersing the specimen in water for 8 hours and then placing it in a dryer at a temperature of 60°C for 16 hours. After the weather resistance test, peeling at the bonded portion of the test specimen was visually observed. As a result, none of the test specimens of Examples 1 to 4 exhibited peeling at the bonded portion.

[0047] Comparative Example 1 Glued laminated timber L as shown in Figure 5(e) was produced in the same manner as in Examples 1 to 4, except that an eighth plate and a ninth plate that were not provided with convex strips and concave strips were bonded with the bonding agent 3 e was produced. A test specimen (x: 40 mm, y: 20 mm, thickness: 40 mm) was cut out from the produced glued laminated timber L e from the produced glued laminated timber. A weather resistance test was performed on the test specimen in the same manner as in Examples 1 to 4, and peeling at the bonded portion was visually observed. As a result, peeling between the eighth plate and the ninth plate was observed on one side in the x direction in the test specimen of Comparative Example 1.

[0048] (Others) Preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications to the configuration can be made without departing from the spirit of the present invention. The present invention is not limited by the above description, and is limited only by the scope of the appended claims. For example, in the above embodiments, a window frame and a stile of a sliding door are described as the frame body, but a door frame that is partially exposed outdoors can also be manufactured using the glued laminated timber according to the present invention in the same manner as a window frame or the like. [Industrial Applicability]

[0049] According to the laminated timber of the present invention, even if the laminated timber is composed of different types of board material, delamination of the joint surfaces can be suppressed, making it useful. [Explanation of Symbols]

[0050] 1 plate material 2 Board material 3. Bonding agent 4. Window frame (frame body) L1~L4, L a ~L e Laminated wood 11,12,13 Convex stripes 21,22,23 grooves 52 Frame (frame body)

Claims

1. A laminated timber in which two or more boards are joined together in the thickness direction with a bonding agent, One of the boards to be joined has multiple protrusions on its joining surface, and the other board has multiple recesses on its joining surface into which the multiple protrusions fit. The difference in total dry specific gravity between one board and the other board being joined is 0.1 g / cm³. ３ The laminated timber is characterized by the above.

2. The laminated timber according to claim 1, wherein at least one of the board materials to be joined has been subjected to one of the following treatments: acetylation, kebony treatment, thermo treatment, or flanwood treatment.

3. The laminated timber according to claim 1, wherein the shape of the cross-section perpendicular to the direction of extension of the convex and concave ridges is at least one of polygonal, arc-shaped, or corrugated.

4. The laminated timber according to claim 1, wherein the height of the aforementioned protrusions is 5 mm or less.

5. The laminated wood according to claim 1, wherein the spacing between the protrusions is in the range of 5 mm or more and 15 mm or less.

6. The laminated timber according to claim 1, wherein the spacing between the protrusions is the same as or twice the maximum width of the cross section perpendicular to the direction in which the protrusions extend.

7. The laminated timber according to claim 1, wherein the bonding agent is at least one of polyurethane resin, aqueous polymer-isocyanate, epoxy resin, and resorcinol resin.

8. A frame made of laminated timber according to any one of claims 1 to 7, wherein a portion of it is exposed to the outdoors, A frame characterized in that the laminated timber is used such that boards with a high total dry specific gravity are located on the outdoor side and boards with a low total dry specific gravity are located on the indoor side.

9. The frame according to claim 8, wherein the frame is at least one of a window frame and a door frame.

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