JP7678740B2 - Fire-retardant chemical retaining boards, fire-resistant wood composite materials and fire-resistant wooden structural materials - Google Patents

Description

The present invention relates to a flame retardant chemical holding plate, a fire-resistant wood composite material, and a fire-resistant wooden structural material.

Various technologies have been proposed to impart fire resistance to wood. For example, Patent Document 1 describes a fire-retardant support that includes a wood substrate having multiple openings and a solid material containing a fire-retardant agent that is filled into the openings. Patent Document 1 also describes a fire-resistant wood composite material that is made by laminating multiple fire-retardant support bodies.

JP 2020-59126 A

In the fire-resistant wood composite material of Patent Document 1, in order to obtain high fire resistance, it is desirable to control the relative positions of the stacked flame retardant chemical supports. Specifically, it is desirable to stack multiple flame retardant chemical supports with the positions of the openings shifted. However, it is not necessarily easy to control the positions of the openings of the stacked flame retardant chemical supports with high precision.

In addition, in Patent Document 1, the openings in the wood base material are through holes, so when the openings are filled with a flame retardant-containing solid material after the openings are formed, the flame retardant-containing solid material may protrude from the openings. If the flame retardant-containing solid material protrudes from the openings, it must be repaired manually, so it is not necessarily easy to put the manufacturing process of the fire-resistant wood composite material of Patent Document 1 into an on-line production line.
As described above, the fire-resistant wood composite material of Patent Document 1 has room for improvement in terms of ease of production.
Furthermore, in order to improve the fire resistance of the fire-resistant wood composite material of Patent Document 1, it was necessary to increase the number of flame retardant agent holders to be laminated, and there was room for improvement in terms of improving the fire resistance while reducing the thickness of the fire-resistant wood composite material.

The object of the present invention is to provide a flame retardant agent-retaining board, a fire-resistant wood composite material, and a fire-resistant wooden structural material that can be easily manufactured and that is both thin and has fire resistance.

The present invention provides a flame retardant agent holding plate used to form a fire-resistant coating layer, the flame retardant agent holding plate comprising a wood base material having a first direction and a second direction perpendicular to the first direction, non-through holes on each of one side and the other side, and a flame retardant agent-containing solid material filled in each of the holes, the central points of the holes on the one side being offset from the central points of the holes on the other side in the first direction or the second direction, or in both directions.

The present invention also provides a fire-resistant wood composite material having a structure in which multiple flame retardant chemical holding plates are laminated together, the flame retardant chemical holding plates being the flame retardant chemical holding plates of the present invention.

The present invention also provides a fire-resistant wooden structural material having a load-bearing section made of a square timber and a fire-resistant coating layer covering three or four axial sides of the load-bearing section, each of the fire-resistant coating layers covering the sides containing the flame-retardant agent-holding plate of the present invention.

The present invention provides a flame retardant agent-retaining plate, a fire-resistant wood composite material, and a fire-resistant wooden structural material that can be easily manufactured and that is both thin and has fire resistance.

FIG. 1 is a perspective view showing a fire-resistant wood composite material according to a preferred embodiment of the present invention. 2(a) is a plan view of part A in FIG. 1, and FIG. 2(b) is a cross-sectional view of one flame retardant agent holding plate along line IIb-IIb in FIG. 2(a). FIG. 3 is a cross-sectional view showing a part of the cross section taken along line III-III in FIG. FIG. 4 is a cross-sectional view showing a modified example of the laminated state of the flame retardant agent holding plates, and corresponds to FIG. FIG. 5(a) is a cross-sectional view of a fire-resistant wooden structural material according to a preferred embodiment of the present invention, FIG. 5(b) is a modified example of the fire-resistant wooden structural material shown in FIG. 5(a), and FIG. 5(c) is a cross-sectional view of a fire-resistant wooden structural material according to another embodiment of the present invention. FIG. 6 is a graph showing the results of a combustion test performed on the test specimen of Example 1 and measuring the temperature of the test specimen. FIG. 7 is a graph showing the results of a combustion test performed on the test specimen of Example 2 and measuring the temperature of the test specimen. FIG. 8(a) is a diagram showing the positions at which temperature changes were measured when a combustion test was conducted on the test specimen of Example 3, and FIG. 8(b) is a graph showing the results of measuring the temperature of the test specimen. FIG. 9(a) is a diagram showing the positions at which temperature changes were measured when a combustion test was conducted on the test specimen of Example 4, and FIG. 9(b) is a graph showing the results of measuring the temperature of the test specimen.

The present invention will now be described in detail based on preferred embodiments thereof.
A fire-resistant wood composite material 1 according to a preferred embodiment of the present invention has a configuration in which a plurality of flame retardant agent holding plates 10 are laminated in the thickness direction, as shown in Fig. 1. In the fire-resistant wood composite material 1, two flame retardant agent holding plates 10 are laminated in the thickness direction Z. In a plan view, the flame retardant agent holding plates 10 have a first direction X and a second direction Y perpendicular to the first direction X. In the embodiment shown in Fig. 1, the two flame retardant agent holding plates 10 are laminated with the first direction X and the second direction Y aligned. The flame retardant agent holding plates 10 are used to form a fire-resistant coating layer.

As shown in Fig. 2(a) and Fig. 2(b), the flame retardant agent holding plate 10 comprises a wood base material 20 and a flame retardant agent-containing solid material 30. The wood base material 20 has one side S1 and the other side S2 in the thickness direction Z. The wood base material 20 has non-penetrating openings 21, 22 on the one side S1 side and the other side S2 side, respectively. The flame retardant agent-containing solid material 30 is filled in the opening 21 on the one side S1 side and the opening 22 on the other side S2 side, respectively.

As described above, the flame retardant holding plate 10 comprises a wood base material 20 having a plurality of openings 21, 22, and a flame retardant-containing solid material 30 filled in each of the openings 21, 22. With this configuration, the flame retardant holding plate 10 is cut off by the flame retardant-containing solid material 30 filled in each of the openings 21, 22 of the wood base material 20, so that when the flame retardant holding plate 10 burns, for example, large cracks are unlikely to occur in the flame retardant holding plate 10. Here, cutting off the edges means that the extension of the crack is stopped at the opening.

As shown in FIG. 2(b), the openings 21 and 22 do not penetrate the wood substrate 20. Specifically, the opening 21 on the one surface S1 side (hereinafter also referred to as the "one surface side opening") is open on the one surface S1 side and has a bottom 21b on the other surface S2 side. The opening 22 on the other surface S2 side (hereinafter also referred to as the "other surface side opening") is open on the other surface S2 side and has a bottom 22b on the one surface S1 side. In this embodiment, each opening 21 and 22 has a substantially cylindrical shape, and the shapes of the multiple openings 21 and 22 are substantially the same.

In the fire-resistant wood composite material of the present invention, the positions of the center points of the one-side opening and the other-side opening in the flame retardant agent holding plate are offset in the first direction, the second direction, or both directions. In the fire-resistant wood composite material 1 of this embodiment, as shown in FIG. 2(a), the positions of the center points 21a, 22a of the one-side opening 21 and the other-side opening 22 in the flame retardant agent holding plate 10 are offset in both the first direction X and the second direction Y. The positions of the one-side opening 21 and the other-side opening 22 in the flame retardant agent holding plate 10 according to this embodiment will be described in detail below.

2(a), the first side openings 21 are formed at equal intervals in each of the first direction X and the second direction Y. More specifically, the first side openings 21 form a first first side opening row 21R in which a plurality of the first side openings 21 are arranged in a row at a constant interval Py along the second direction Y. The first first side opening row 21R is arranged in a plurality of rows at intervals in the first direction X. The positions of the center points 21a of the first side openings 21 in the second direction Y of the first side openings 21 adjacent to each other in the first direction X coincide with each other. The first side openings 21 form a second first side opening row 21L in which a plurality of the first side openings 21 are arranged in a row at a constant interval Px along the first direction X. The second first side opening row 21L is arranged in a plurality of rows at intervals in the second direction Y. The first surface side openings 21 constituting the second first surface side opening row 21L adjacent to each other in the second direction Y have the same position of the center points 21a of the openings 21 in the first direction X.

In other words, the first surface side openings 21 constituting the first surface side opening row 21R adjacent in the first direction X form a second surface side opening row 21L arranged in a row at a constant interval along the first direction X. The interval Py of the first surface side openings 21 constituting the first surface side opening row 21R and the interval Px of the openings 21 constituting the second surface side opening row 21L are the same. The "interval Py of the first surface side openings 21 constituting the first surface side opening row 21R" refers to the distance between the center points 21a of the first surface side openings 21 adjacent in the second direction Y, and the "interval Px of the second surface side openings 21 constituting the second surface side opening row 21L" refers to the distance between the center points 21a of the first surface side openings 21 adjacent in the first direction X (see FIG. 2(a)).

As shown in FIG. 2(a), the other side openings 22 are formed at equal intervals in each of the first direction X and the second direction Y. More specifically, the other side openings 22 form a first other side opening row 22R in which a plurality of the other side openings 22 are arranged in a row at a constant interval Qy along the second direction Y. The first other side opening row 22R is arranged in a plurality of rows at intervals in the first direction X. The other side openings 22 constituting the first other side opening row 22R adjacent to each other in the first direction X have the same position of the center points 22a of the other side openings 22 in the second direction Y. In addition, the other side openings 22 form a second other side opening row 22L in which a plurality of the other side openings 22 are arranged in a row at a constant interval Qx along the first direction X. The second other side opening row 22L is arranged in a plurality of rows at intervals in the second direction Y. The other side openings 22 constituting the second other side opening row 22L adjacent in the second direction Y have the same position of the center points 22a of the openings 22 in the first direction X.

In other words, the other-side openings 22 constituting the first other-side opening row 22R adjacent in the first direction X form a second other-side opening row 22L arranged in a row at regular intervals along the first direction X. The interval Qy between the other-side openings 22 constituting the first other-side opening row 22R and the interval Qx between the openings 22 constituting the second other-side opening row 22L are the same. The "interval Qy between the other-side openings 22 constituting the first other-side opening row 22R" refers to the distance between the center points 22a of the other-side openings 22 adjacent in the second direction Y, and the "interval Qx between the other-side openings 22 constituting the second other-side opening row 22L" refers to the distance between the center points 22a of the other-side openings 22 adjacent in the first direction X (see FIG. 2(a)).

In the flame retardant agent holding plate 10 according to this embodiment, as described above, the positions of the center points 21a, 22a of the one-side opening 21 and the other-side opening 22 are offset in both the first direction X and the second direction Y. More specifically, the first other-side opening row 22R is arranged between the first one-side opening row 21R adjacent to each other in the first direction X. The first one-side opening row 21R and the first other-side opening row 22R are offset by half a pitch in the second direction Y. In addition, the second other-side opening row 22L is arranged between the second one-side opening row 21L adjacent to each other in the second direction Y. Furthermore, the second one-side opening row 21L and the second other-side opening row 22L are offset by half a pitch in the first direction X. Above, we have described the arrangement of the openings 21, 22 in the upper flame retardant chemical holding plate 10 of the two stacked flame retardant chemical holding plates 10, but the same applies to the arrangement of the openings 21, 22 in the lower flame retardant chemical holding plate 10.

In the fire-resistant wood composite material 1, as shown in Figs. 1 and 3, two flame retardant agent holding plates 10 are laminated. In this embodiment, as shown in Fig. 3, the openings 21, 22 formed on the opposing surfaces of the flame retardant agent holding plates 10 adjacent to each other in the thickness direction Z do not overlap. Specifically, the opening 22 on the other side of the flame retardant agent holding plate 10 does not overlap with the opening 21 on one side of the flame retardant agent holding plate 10 adjacent to the flame retardant agent holding plate 10 in the thickness direction Z.

In this embodiment, the positional relationship between adjacent flame retardant agent holding plates 10 in the thickness direction Z is not particularly limited, and for example, as shown in FIG. 4, the openings 21, 22 formed on the opposing surfaces of adjacent flame retardant agent holding plates 10 in the thickness direction Z may completely overlap each other. Note that the openings 21, 22 formed on the opposing surfaces of adjacent flame retardant agent holding plates 10 in the thickness direction Z may partially overlap each other.

The fire-resistant wood composite material 1 of this embodiment can be manufactured, for example, as follows.
First, the openings 21, 22 are formed in a wood substrate 20 that does not have openings 21, 22, with the positions of the center points 21a, 22a shifted in the first direction X and the second direction Y. Next, the openings 21, 22 are filled with a flame retardant-containing solid material 30. The flame retardant-holding plates 10 thus manufactured are stacked together to manufacture the fire-resistant wood composite material 1. The stacked flame retardant-holding plates 10 are preferably joined together, for example, with an adhesive or the like.

There is no particular restriction on the order in which the openings 21 and 22 are formed and the order in which the flame retardant-containing solid material 30 is filled. Either one of the openings 21 and the openings 22 on the one side may be formed after the other opening is formed, or both openings 21 and 22 may be formed simultaneously. Alternatively, either one of the openings 21 and the openings 22 on the one side may be filled with the flame retardant-containing solid material 30, and then the other opening may be filled with the flame retardant-containing solid material 30, or both openings 21 and 22 may be filled with the flame retardant-containing solid material 30 at the same time. Alternatively, either one of the openings 21 and the openings 22 on the one side may be formed, and then the opening formed may be filled with the flame retardant-containing solid material 30, and then the other opening may be formed, and then the opening formed may be filled with the flame retardant-containing solid material 30. Details of the manufacturing method of the fire-resistant wood composite material 1 will be described later.

According to the fire-resistant wood composite material 1 of this embodiment, the one-side opening 21 and the other-side opening 22 of the flame retardant holding plate 10 are non-through openings, so when the openings 21, 22 are filled with the flame retardant-containing solid material 30, the flame retardant-containing solid material 30 is less likely to pop out of the openings 21, 22. Therefore, when manufacturing the fire-resistant wood composite material 1, there is no need to manually repair the fire-resistant wood composite material 1 during manufacturing, so it is easy to put the manufacturing process of the fire-resistant wood composite material 1 into an line.

As described above, in the fire-resistant wood composite material 1 of this embodiment, the position of the center point 21a of the one-side opening 21 and the position of the center point 22a of the other-side opening 22 in the flame-retardant agent holding plate 10 are offset in both the first direction X and the second direction Y. With this configuration, even if a portion of one side of the fire-resistant wood composite material 1, i.e., a portion of one side S1 of the uppermost flame-retardant agent holding plate 10 among the flame-retardant agent holding plates 10 adjacent in the thickness direction Z, that is not the one-side opening 21, burns and the combustion progresses downward in the thickness direction Z, the other-side opening 22 filled with the flame-retardant agent-containing solid 30 is located below that portion in the thickness direction Z, so that the combustion can be prevented from progressing downward in the thickness direction Z. Therefore, it is not necessarily necessary to stack the flame retardant holding plates 10 so that the flame retardant-containing solid material 30 of another flame retardant holding plate 10 is located below in the thickness direction Z of the portion of the flame retardant holding plate 10 that is not the one-side opening 21. In other words, in the fire-resistant wood composite material 1 of this embodiment, the positional relationship between the stacked flame retardant holding plates 10 can be arbitrary, so that it is easy to stack a plurality of flame retardant holding plates 10 to form the fire-resistant wood composite material 1.
In this manner, the fire-resistant wood composite material 1 of this embodiment can be easily manufactured.

In addition, in the fire-resistant wood composite material 1 of this embodiment, the positions of the center points 21a, 22a of the one-side opening 21 and the other-side opening 22 of the flame retardant agent holding plate 10 are in the positional relationship as described above, so that the combustion in the flame retardant agent holding plate 10 can be prevented from progressing downward in the thickness direction Z. Therefore, even if the number of flame retardant agent holding plates 10 in the fire-resistant wood composite material 1 is small, the fire resistance of the fire-resistant wood composite material 1 can be maintained. However, the number of flame retardant agent holding plates 10 stacked in the fire-resistant wood composite material 1 is not particularly limited. In this embodiment, two flame retardant agent holding plates 10 are stacked, but three or more flame retardant agent holding plates 10 may be stacked. For example, two to four flame retardant agent holding plates 10 may be stacked.
In addition, in the fire-resistant wood composite material 1 of this embodiment, as described above, the one-side opening 21 and the other-side opening 22 of the flame retardant agent holding plate 10 are non-through. Therefore, for example, it is not necessary to provide a sealing layer on the one side S1 side or the other side S2 side of the wood substrate 20 for the purpose of preventing the flame retardant agent-containing solid 30 from falling out of the one-side opening 21 or the other-side opening 22. Therefore, it is possible to prevent the thickness of the flame retardant agent holding plate 10 from becoming thicker than the thickness of the wood substrate 20. Therefore, it is possible to prevent the fire-resistant wood composite material 1 in which the flame retardant agent holding plate 10 is laminated from becoming thicker.
In this way, the fire-resistant wood composite material 1 of this embodiment can achieve both thinness and fire resistance.

The flame retardant agent holding plate 10 used in the fire-resistant wood composite material 1 has a one-side opening 21 and a second-side opening 22 that are non-through holes, so that when the flame retardant agent-containing solid material 30 is filled, the flame retardant agent-containing solid material 30 is less likely to pop out, making it easy to manufacture. In addition, whether it is used as a single layer or in a laminated form, it is easy to achieve both thinness and fire resistance.

2(b), the flame retardant agent holding plate 10 according to this embodiment has an aperture overlap region 25 in its thickness direction Z where both a part of the one-side aperture 21 and a part of the other-side aperture 22 are present. In other words, in its thickness direction Z, the bottom 21b of the one-side aperture 21 is located closer to the other surface S2 of the flame retardant agent holding plate 10 than the bottom 22b of the other-side aperture 22. More specifically, the total depth (H1+H2) of the depth H1 of the one-side aperture 21 and the depth H2 of the other-side aperture 22 of the flame retardant agent holding plate 10 is greater than the thickness H of the flame retardant agent holding plate 10.

As shown in FIG. 2(b), the flame retardant holding plate 10 preferably has an aperture overlap region 25 in the central region 10C in the thickness direction Z. This can further improve the fire resistance of the flame retardant holding plate 10, and therefore the fire resistance of the fire-resistant wood composite material 1. In order to make this effect more pronounced, the ratio H3/H of the length H3 in the thickness direction Z of the aperture overlap region 25 to the thickness H of the flame retardant holding plate 10 is preferably 0.04 or more, more preferably 0.08 or more. The upper limit of the ratio H3/H can be set to, for example, 0.8. The length H3 in the thickness direction Z of the aperture overlap region 25 can be calculated by subtracting the thickness H of the flame retardant holding plate 10 from the total depth (H1+H2) of the depth H1 of the one-side opening 21 and the depth H2 of the other-side opening 22.

It is preferable that the ratio H3/H is within the above-mentioned range in at least one of the multiple flame retardant chemical holding plates 10 contained in the fire-resistant wood composite 1, and it is more preferable that the ratio H3/H is within the above-mentioned range in all of the multiple flame retardant chemical holding plates 10.
The central region 10C of the flame retardant agent holding plate 10 can be, for example, the two central regions when the flame retardant agent holding plate 10 is divided into four equal regions in the thickness direction Z, as shown in FIG. 2(b).

The ratio H1/H of the depth H1 of the one-side opening 21 to the thickness H of the flame retardant holding plate 10 is preferably 0.3 to 0.9, more preferably 0.5 to 0.8. The depth H1 of the one-side opening 21 means the depth of the deepest part of the one-side opening 21. It is preferable that the ratio H1/H is within the above-mentioned range in at least one of the multiple flame retardant holding plates 10 in the fire-resistant wood composite material 1, and it is more preferable that the ratio H1/H is within the above-mentioned range in all of the multiple flame retardant holding plates 10.

The ratio H2/H of the depth H2 of the other side opening 22 to the thickness H of the flame retardant agent holding plate 10 is preferably 0.3 to 0.9, more preferably 0.5 to 0.8. The depth H2 of the other side opening 22 means the depth of the deepest part of the other side opening 22. It is preferable that the ratio H2/H is within the above-mentioned range in at least one of the multiple flame retardant agent holding plates 10 in the fire-resistant wood composite material 1, and it is more preferable that the ratio H2/H is within the above-mentioned range in all of the multiple flame retardant agent holding plates 10.
The ratio H1/H and the ratio H2/H may be the same or different.

The thickness H of the flame retardant agent holding plate 10 is preferably 12 mm or more and 48 mm or less, more preferably 18 mm or more and 30 mm or less. It is preferable that the thickness H of at least one of the multiple flame retardant agent holding plates 10 in the fire-resistant wood composite material 1 is within the above-mentioned range, and it is more preferable that the thickness H of all of the multiple flame retardant agent holding plates 10 is within the above-mentioned range.

In the flame retardant chemical holding plate 10, the one surface side opening 21 and the other surface side opening 22 may overlap each other partially when viewed in a plane of the flame retardant chemical holding plate 10, or they may not overlap as shown in Figure 2 (a).
In the flame retardant agent holding plate 10, it is preferable that 50% to 100% of the first surface openings 21 do not overlap with the other surface openings 22, it is more preferable that 70% to 100% of the first surface openings 21 do not overlap with the other surface openings 22, and it is even more preferable that 90% to 100% of the first surface openings 21 do not overlap with the other surface openings 22. It is preferable that in at least one of the multiple flame retardant agent holding plates 10 in the fire-resistant wood composite material 1, the proportion of the first surface openings 21 that do not overlap with the other surface openings 22 is within the above-mentioned range, and it is more preferable that in all of the multiple flame retardant agent holding plates 10, the proportion of the first surface openings 21 that do not overlap with the other surface openings 22 is within the above-mentioned range.

In the flame retardant holding plate 10, the total opening area of the one-side openings 21 is preferably 9% or more, more preferably 11% or more, more preferably 30% or less, more preferably 22% or less, more preferably 9% or more and 30% or less, and more preferably 11% or more and 22% or less, relative to the area of one surface S1 of the wood substrate 20, from the viewpoint of holding the necessary amount of the flame retardant-containing solid 30. It is preferable that in at least one of the multiple flame retardant holding plates 10 possessed by the fire-resistant wood composite material 1, the ratio of the total opening area of the one-side openings 21 to the area of one surface S1 of the wood substrate 20 is within the above-mentioned range, and it is more preferable that in all of the multiple flame retardant holding plates 10, the ratio of the total opening area of the one-side openings 21 to the area of the one surface S1 is within the above-mentioned range.

In the flame retardant holding plate 10, the total opening area of the other side openings 22 is preferably 9% or more, more preferably 11% or more, more preferably 30% or less, more preferably 22% or less, preferably 9% or more and 30% or less, and more preferably 11% or more and 22% or less, relative to the area of the other side S2 of the wood substrate 20, from the viewpoint of holding a necessary amount of the flame retardant-containing solid 30. It is preferable that in at least one of the multiple flame retardant holding plates 10 possessed by the fire-resistant wood composite material 1, the ratio of the total opening area of the other side openings 22 to the area of the other side S2 of the wood substrate 20 is within the above-mentioned range, and it is more preferable that in all of the multiple flame retardant holding plates 10, the ratio of the total opening area of the other side openings 22 to the other side S2 is within the above-mentioned range.
The ratio of the total opening area of the one-surface openings 21 to the one surface S1 and the ratio of the total opening area of the other-surface openings 22 to the other surface S2 may be the same or different.

From the viewpoints of retaining the necessary amount of flame retardant-containing solid material 30 and preventing large cracks from occurring during a heating test by cutting the edges, the diameter of the one-side opening 21 is preferably 6 mm or more, more preferably 7 mm or more, and preferably 12 mm or less, more preferably 11 mm or less, preferably 6 mm or more and 12 mm or less, and more preferably 7 mm or more and 11 mm or less. It is preferable that the diameter of the one-side opening 21 of at least one of the multiple flame retardant holding plates 10 in the fire-resistant wood composite material 1 is within the above-mentioned range, and it is more preferable that the diameter of the one-side opening 21 of all of the multiple flame retardant holding plates 10 is within the above-mentioned range.

From the viewpoints of retaining the necessary amount of the flame retardant-containing solid material 30 and preventing large cracks from occurring during a heating test by cutting the edges, the diameter of the other side opening 22 is preferably 6 mm or more, more preferably 7 mm or more, preferably 12 mm or less, more preferably 11 mm or less, preferably 6 mm or more and 12 mm or less, and more preferably 7 mm or more and 11 mm or less. It is preferable that the diameter of the other side opening 22 in at least one of the multiple flame retardant holding plates 10 in the fire-resistant wood composite material 1 is within the above-mentioned range, and it is more preferable that the diameter of the other side opening 22 in all of the multiple flame retardant holding plates 10 is within the above-mentioned range.
The diameter of the one surface side opening 21 and the diameter of the other surface side opening 22 may be the same or different.

The flame retardant agent-containing solid 30 may be of the same shape and size as the first surface opening 21 and the second surface opening 22, or may have smaller dimensions than the first surface opening 21 and the second surface opening 22.
More specifically, the volume of the flame retardant-containing solid 30 filled in the one-side opening 21 relative to the volume of the opening 21 is preferably 70% or more, more preferably 90% or more, with the upper limit being 100%. It is preferable that the volume of the flame retardant-containing solid 30 filled in the one-side opening 21 relative to the volume of the opening 21 in at least one of the multiple flame retardant-containing holding plates 10 in the fire-resistant wood composite material 1 is within the above-mentioned range, and it is more preferable that the volume of the flame retardant-containing solid 30 filled in the one-side opening 21 relative to the volume of the opening 21 in all of the multiple flame retardant-containing holding plates 10 is within the above-mentioned range.

The volume of the flame retardant-containing solid 30 filled in the other side opening 22 relative to the volume of the other side opening 22 is preferably 70% or more, more preferably 90% or more, with the upper limit being 100%. It is preferable that in at least one of the multiple flame retardant holding plates 10 possessed by the fire-resistant wood composite material 1, the volume of the flame retardant-containing solid 30 filled in the other side opening 22 relative to the volume of the other side opening 22 is within the above-mentioned range, and it is more preferable that in all of the multiple flame retardant holding plates 10, the volume of the flame retardant-containing solid 30 filled in the other side opening 22 relative to the volume of the other side opening 22 is within the above-mentioned range.

From the viewpoints of holding the necessary amount of flame retardant-containing solid material 30 and preventing large cracks from occurring during a heating test by cutting the edges, the spacing Py and spacing Px of the one-side openings 21 constituting the first one-side opening row 21R and the second one-side opening row 21L are preferably 15 mm or more, more preferably 18 mm or more, and preferably 30 mm or less, more preferably 25 mm or less, preferably 15 mm or more to 30 mm or less, and more preferably 18 mm or more to 25 mm or less (see FIG. 2(a)). It is preferable that the spacing Py and spacing Px of the one-side openings 21 in at least one of the multiple flame retardant holding plates 10 in the fire-resistant wood composite material 1 are within the above-mentioned range, and it is more preferable that the spacing Py and spacing Px of the one-side openings 21 in all of the multiple flame retardant holding plates 10 are within the above-mentioned range.

From the viewpoint of retaining the necessary amount of flame retardant-containing solid 30 and preventing large cracks from occurring during a heating test by cutting the edges, the spacing Qy and spacing Qx of the other side openings 22 constituting the first other side opening row 22R and the second other side opening row 22L are preferably 15 mm or more, more preferably 18 mm or more, and preferably 30 mm or less, more preferably 25 mm or less, preferably 15 mm or more to 30 mm or less, and more preferably 18 mm or more to 25 mm or less (see FIG. 2(a)). It is preferable that the spacing Qy and spacing Qx of the other side openings 22 in at least one of the multiple flame retardant holding plates 10 of the fire-resistant wood composite material 1 are within the above-mentioned range, and it is more preferable that the spacing Qy and spacing Qx of the other side openings 22 in all of the multiple flame retardant holding plates 10 are within the above-mentioned range.

In this embodiment, the one-side openings 21 are formed at equal intervals in each of the first direction X and the second direction Y, but the spacing Py of the one-side openings 21 constituting the first one-side opening row 21R and the spacing Px of the one-side openings 21 constituting the second one-side opening row 21L may be different.
When the interval Py of the first side openings 21 constituting the first side opening row 21R is different from the interval Px of the first side openings 21 constituting the second side opening row 21L, the interval Px of the first side openings 21 constituting the second side opening row 21L is preferably 15 mm or more, more preferably 18 mm or more, more preferably 50 mm or less, more preferably 25 mm or less, more preferably 15 mm or more and 50 mm or less, and more preferably 18 mm or more and 25 mm or less from the viewpoint of preventing an extreme decrease in the strength of the flame retardant agent holding plate 10 itself in one direction and ensuring homogeneity in the agent holding (see FIG. 2 (a)). It is preferable that the interval Px of the first side openings 21 of at least the multiple flame retardant agent holding plates 10 of the fire-resistant wood composite material 1 is within the above-mentioned range, and it is more preferable that the interval Px of the first side openings 21 of all the multiple flame retardant agent holding plates 10 is within the above-mentioned range.

In addition, in this embodiment, the other-side openings 22 are formed at equal intervals in each of the first direction X and the second direction Y, but the spacing Qy of the other-side openings 22 that make up the first other-side opening row 22R and the spacing Qx of the other-side openings 22 that make up the second other-side opening row 22L may be different.
When the interval Qy of the other side openings 22 constituting the first other side opening row 22R is different from the interval Qx of the other side openings 22 constituting the second other side opening row 22L, the interval Qx of the other side openings 22 constituting the second other side opening row 22L is preferably 15 mm or more, more preferably 18 mm or more, preferably 50 mm or less, more preferably 25 mm or less, preferably 15 mm or more and 50 mm or less, and more preferably 18 mm or more and 25 mm or less from the viewpoint of preventing an extreme decrease in the strength of the flame retardant agent holding plate 10 itself in one direction and ensuring homogeneity in the holding of the agent (see FIG. 2(a)). It is preferable that the interval Qx of the other side openings 22 of at least the multiple flame retardant agent holding plates 10 of the fire-resistant wood composite material 1 is within the above-mentioned range, and it is more preferable that the interval Qx of the other side openings 22 of all the multiple flame retardant agent holding plates 10 is within the above-mentioned range.

In the fire-resistant wood composite material 1 of this embodiment, as shown in Fig. 3, nothing is arranged on the outer surface side of the flame retardant chemical holding plate 10 located at both ends in the thickness direction Z, but as shown in Fig. 4, a decorative layer 5 may be arranged on the side opposite to the side where another flame retardant chemical holding plate 10 is present in at least one of the flame retardant chemical holding plates 10 located at both ends in the thickness direction Z. Specifically, it is preferable that the decorative layer 5 constitutes the surface of the fire-resistant wood composite material 1 that is heated from the outside in the event of a fire. As the decorative layer 5, a decorative sheet made of a veneer, synthetic resin, paper, etc., as well as a coating layer, etc. can be used.
By arranging a decorative layer 5 on the side opposite to the side on which another flame retardant chemical holding plate 10 is present in at least one of the flame retardant chemical holding plates 10 located at both ends in the thickness direction Z, it is possible to improve the design of the fire-resistant wood composite material 1.
The flame retardant agent holding plates 10 located at both ends in the thickness direction Z are the flame retardant agent holding plates located at the ends or closest to the ends in the thickness direction Z among the multiple flame retardant agent holding plates 10.

At least one of the flame retardant holding plates 10 located at both ends in the thickness direction Z may have a flame retardant applied to the surface S1 opposite to the side where another flame retardant holding plate 10 is present. Specifically, it is preferable that the flame retardant is applied to the surface of the fire-resistant wood composite material 1 that constitutes the side that is heated from the outside in the event of a fire. When the fire-resistant wood composite material 1 has a decorative layer 5, the flame retardant may be applied to the surface of the decorative layer 5 opposite to the flame retardant holding plate 10. Also, the flame retardant may be disposed between the decorative layer 5 and the flame retardant holding plate 10 by a method such as applying the flame retardant to one or both of the decorative layer 5 and the flame retardant holding plate 10.
The flame retardant applied to the decorative layer 5 or the flame retardant holding plate 10 may be the same as the solid flame retardant contained in the flame retardant-containing solid material 30, or may be different.
By applying a flame retardant agent to the surface constituting the outer side of the fire-resistant wood composite material 1, it is possible to further improve the fire resistance of the fire-resistant wood composite material 1.

Next, the constituent materials of the fire-resistant wood composite material 1 of this embodiment will be described.
The wood substrate 20 is made of a laminate of multiple veneers or boards. When the wood substrate 20 is made of a laminate of veneers, the laminate may include multiple types of veneers with different fiber orientation directions, or may be made of only veneers with the same fiber orientation direction, such as a laminated veneer board (LVL). Instead of being made of a laminate of multiple veneers, the wood substrate 20 may be made of a single board that is a non-laminated material.
The species of wood constituting the wood substrate 20, for example the raw wood of the veneer, may be a conifer or a broadleaf tree, such as oak, teak, walnut, falcata, balsa, red lauan, ash, elm, birch, paulownia, cedar, cypress, larch, Ezo spruce, Todomatsu, Akamatsu, Hiba, whitewood, European scotch pine, Dahurica larch, Douglas fir, etc. The species of raw wood may be one or a laminate of two or more species selected from the above-mentioned tree species, and may be used as the wood substrate 20.
Among these, from the viewpoints of reducing the amount of heat generated during combustion and being easily secured as a raw material for veneers, it is preferable to use coniferous trees such as cedar and todomatsu, which are relatively light and easy to secure as raw materials. From the same viewpoint, it is preferable to use one having an air-dry density of 0.3 to 0.6 g/ ^cm3 , and more preferably one having an air-dry density of 0.4 to 0.5 g/ ^cm3 . The air-dry density is determined by the average value of multiple veneer laminates.

The flame retardant-containing solid 30 is a solid in a solid state. The flame retardant-containing solid 30 may be a cured product or a compressed powder. It is preferable that the flame retardant-containing solid 30 is water resistant. In order to impart water resistance and other properties to the flame retardant-containing solid 30, the surface of the flame retardant-containing solid 30 may be coated with a material that has the function of imparting water resistance, such as acrylic resin, urethane resin, urethane acrylic resin, alkyd resin, polyester resin, silicone-modified polyester resin, silicone-modified acrylic resin, epoxy resin, polycarbonate resin, silicate resin, fluororesin, chlorine-based resin, and polyolefin resin. Commercially available products such as a solventless moisture-curing silicone coating composition (KR-400, manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used.

The hardened material is a product of hardening a hardenable composition containing a solid flame retardant. In the manufacturing process of the fire-resistant wood composite material 1, a paste-like hardenable composition may be filled in the openings 21, 22 in a fluid state and then hardened to form a hardened material, or a paste-like hardenable composition may be hardened to form a hardened material and then the hardened material may be filled into the openings 21, 22.
A curable composition is one that is cured under a predetermined condition or operation. Such a curable composition includes a component that is cured under a predetermined condition or operation. Examples of the predetermined condition or operation include room temperature curing, moisture curing, heat curing at 40 to 150°C, and curing by chemical reaction in the presence of a catalyst. In addition, a conductor such as iron powder may be added to the curable composition and cured by high-frequency heating. In addition, the curable composition may be in the form of a fluid containing a solvent at the manufacturing stage. In this case, the solvent is volatilized over time or by heating, etc., so that the curable composition can be made into a cured product. An organic solvent or the like can be used as the solvent.

Room temperature curing components are components that harden when left at room temperature in the air, and examples of such components include oxidation-curing paints and moisture-curing paints. Oxidation-curing components are components that harden by oxidative polymerization via oxygen in the air, and examples of such components include paints containing hydrocarbon compounds with unsaturated bonds. Moisture-curing components are components that harden by reacting with moisture in the air, and examples of such components include silicone-based paints with alkoxy groups or silanol groups. 40-150°C heat-curing components are components that harden when heated to 40-150°C, and examples of such components include urethane-based paints that harden by the reaction of hydroxyl groups with blocked isocyanates, and epoxy-based paints that harden by the reaction of epoxy groups or ring-opening polymerization.

The cured product of the present invention may contain a curing catalyst for the purpose of promoting the curing reaction, and the type, mixing amount, and addition method of the curing catalyst can be determined by known methods and conditions according to the type of composition. When the curable composition contains a component that cures by a chemical reaction in the presence of a catalyst, it is preferable that the curable composition contains a curing catalyst. Examples of the curing catalyst include basic compounds such as lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methylate, sodium propionate, potassium propionate, sodium acetate, potassium acetate, sodium formate, potassium formate, trimethylbenzylammonium hydroxide, tetramethylammonium hydroxide, tetramethylammonium acetate, n-hexylamine, tributylamine, diazabicycloundecene (DBU), and dicyandiamide; metal-containing compounds such as tetraisopropyl titanate, tetrabutyl titanate, titanium acetylacetonate, aluminum triisobutoxide, aluminum triisopropoxide, tris(acetylacetonate)aluminum, diisopropoxy(ethylacetoacetate)aluminum, aluminum perchlorate, aluminum chloride, cobalt octylate, cobalt acetylacetonate, iron acetylacetonate, tin acetylacetonate, dibutyltin octylate, and dibutyltin laurate; and acidic compounds such as p-toluenesulfonic acid and trichloroacetic acid. Among these, sodium propionate, sodium acetate, sodium formate, trimethylbenzylammonium hydroxide, tetramethylammonium hydroxide, tris(acetylacetonate)aluminum, diisopropoxy(ethylacetoacetate)aluminum, etc. are particularly mentioned, and among these, metal-containing compounds such as aluminum catalysts containing organic ligands and titanium catalysts containing organic ligands are preferred.

In this embodiment, it is preferable that the curable component contains a curable compound. The curable compound is a compound that cures under specified conditions or operations. Examples of the specified conditions or operations include those described above. Examples of the curable compound include moisture-curable or heat-curable paint compositions containing resin components such as acrylic resin, urethane resin, urethane acrylic resin, alkyd resin, polyester resin, silicone-modified polyester resin, silicone-modified acrylic resin, epoxy resin, polycarbonate resin, silicate resin, fluororesin, chlorine-based resin, and polyolefin resin.

The curable compound is preferably a compound represented by the following general formula (1) or a hydrolysis condensate thereof, or both.
SiR ¹ _(4-n) R ² _n (1)
(In the formula, each R1 independently represents a hydrogen atom, or an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, which may be substituted with one or more amino groups, epoxy groups, acid anhydride groups, maleimide groups, vinyl groups, allyl groups, acrylic groups, methacrylic groups, or heterocyclic groups; each R2 independently represents a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom; and n represents an integer of 1 to 4.)
The n is preferably 3. A part or all of the R1 is preferably an alkyl group having 6 to 20 carbon atoms. It is also preferable that a part or all of the R1 is an alkyl group having 1 to 20 carbon atoms substituted with one or more epoxy groups.

From the viewpoints of dispersion of the flame retardant agent, ease of handling of the curable compound, formation of a char layer after combustion, and improvement of water resistance, it is preferable that 50 mass % or more of the curable compound is a compound represented by the above formula (1), more preferably 70 mass % or more is a compound represented by the above formula (1), and even more preferably 90 mass % or more is a compound represented by the above formula (1).

As described above, the curable composition contains a solid flame retardant agent. In this embodiment, the curable composition preferably contains a component that is cured under specified conditions or operations, and the content of the solid flame retardant agent is 90 mass% or less. The preferred range of the content of the solid flame retardant agent in the curable composition will be described later.

A solid flame retardant is a chemical agent having flame retardancy. Examples of solid flame retardants include phosphorus compounds and boron compounds. Examples of phosphorus compounds include organic phosphorus compounds, phosphoric acid, phosphoric acid esters, and phosphates. Specific examples of such compounds include diammonium hydrogen phosphate, ammonium dihydrogen phosphate, diguanidine phosphate, ammonium polyphosphate, hydrophobized ammonium polyphosphate, and guanylurea phosphate. Examples of boron compounds include organic boron compounds, boric acid, borax, boron oxide, boric acid esters, and borate salts. Examples of compounds other than phosphorus compounds and boron compounds include ammonium sulfate and zinc chloride. Among these, it is preferable to use one or more compounds selected from the group consisting of organic phosphorus compounds, phosphoric acid, phosphoric acid esters, phosphate salts, organic boron compounds, boric acid, boric acid esters, and borates, and it is more preferable to use boric acid. The solid flame retardant components may be used alone or in combination of two or more compounds.

The green compact is formed by compacting powder. In this embodiment, from the viewpoint of facilitating the formation of the green compact by compacting, it is preferable to compact the powder in a mixed state with a binder. The powder according to this embodiment contains a solid flame retardant. As the binder, a known binder used for forming a green compact can be used, and examples of the binder include resin components such as polyvinyl alcohol resin, acrylic resin, urethane resin, urethane acrylic resin, alkyd resin, polyester resin, silicone-modified polyester resin, silicone-modified acrylic resin, epoxy resin, polycarbonate resin, silicate resin, fluororesin, chlorine-based resin, and polyolefin resin. A curable composition can also be used as the binder.

As described above, the powder compact contains a solid flame retardant agent. In this embodiment, the powder compact is formed by compacting powder, and the content of the solid flame retardant agent is preferably 80 mass% or more. The preferred range of the content of the solid flame retardant agent in the powder compact will be described later.

The flame retardant agent holding plate 10 preferably has a flame retardant agent-containing solid 30 held per unit volume of 90 kg/m 3 or more, more preferably 100 kg/m 3 or more, more preferably 270 kg/m ³ or less, more preferably 200 kg/m 3 or less, more preferably 90 kg/m ³ or more and 270 kg/m ³ or less, and more preferably 100 kg/m ³ or more and 200 kg/m ³ or less, from the viewpoint of ensuring the strength of ^the flame retardant agent holding plate ¹⁰ itself, improving heat absorption performance during ^combustion , and holding the carbonized heat insulating layer. It is preferable that the amount of flame retardant agent-containing solid 30 held per unit volume in at least one of the multiple flame retardant agent holding plates 10 possessed by the fire-resistant wood composite material 1 is within the above-mentioned range, and it is more preferable that the amount of flame retardant agent-containing solid 30 held per unit volume in all of the multiple flame retardant agent holding plates 10 is within the above-mentioned range.

By using a solid material in a solid state as the flame retardant-containing solid material 30, it becomes easier to prevent uneven impregnation of the flame retardant and uneven content of the flame retardant during drying, and it becomes easier to make the content of the flame retardant in the flame retardant holding plate 10 uniform and to make the content of the solid flame retardant in the flame retardant holding plate 10 a desired amount, so it becomes possible to ensure stable fire resistance. Conventionally, as a technique for imparting fire resistance to wood, a method is known in which a flame retardant dissolved in water is impregnated into the wood and then the wood is dried. However, with this method, uneven impregnation of the flame retardant occurs during impregnation, and the content of the flame retardant on the surface side of the wood becomes higher than the inside of the wood during drying, resulting in uneven content of the flame retardant throughout the wood, making it difficult to ensure stable fire resistance in the wood.

In addition, in this embodiment, a hardened material or a compressed powder is used as the solid material 30 containing the flame retardant agent, which is a solid material. Therefore, even if the fire-resistant wood composite material 1 becomes wet with water, the flame retardant agent is less likely to dissolve, and water resistance can be improved.

From the viewpoint of improving the fire resistance of the fire-resistant wood composite material 1, the curable composition preferably contains 50 to 90% by mass of the solid flame retardant, more preferably 60 to 85% by mass, and even more preferably 65 to 80% by mass. From the same viewpoint, the green compact preferably contains 80% or more by mass of the solid flame retardant, more preferably 90% or more by mass, and even more preferably 95% or more by mass. The green compact may be made of only the solid flame retardant, i.e., may contain 100% by mass of the solid flame retardant agent, but if it is 100% by mass, the amount of binder used will be reduced, making it difficult to set the conditions for compression molding, so 99% by mass or less is preferable, and more preferably 97% by mass or less.

Next, a method for producing the fire-resistant wood composite material 1 of this embodiment will be described.
First, the production of a fire-resistant wood composite material 1 having a hardened material as the flame retardant-containing solid material 30 will be described.
First, the openings 21 and 22 are formed in the wood substrate 20 in which the openings 21 and 22 are not formed, with the positions of the center points 21a and 22a shifted in the first direction X and the second direction Y. Separately, the hardening composition is placed in a container having a shape substantially the same as that of the openings 21 and 22, and the hardening composition is hardened in the container. In this way, a flame retardant-containing solid material 30, which is a hardened product, is obtained. Next, the openings 21 and 22 are filled with the flame retardant-containing solid material 30. Prior to filling the openings 21 and 22 with the flame retardant-containing solid material 30, an adhesive may be applied to the surface of the flame retardant-containing solid material 30 or to the peripheral surface of the openings 21 and 22. In this way, it is possible to prevent the flame retardant-containing solid material 30 from falling out of the openings 21 and 22. In this way, the flame retardant-containing solid material 30 is manufactured. The flame retardant-containing solid material 10 manufactured in this way is laminated to each other to manufacture a fire-resistant wood composite material 1.

The method for curing the curable composition is not particularly limited. Examples of the method for curing the curable composition include a method of curing under the specified conditions or operations described above. For example, the curable composition may be cured by adding a curing catalyst to a container containing the curable composition and causing a chemical reaction, or the curable composition may be left in the container and cured by reacting the curing catalyst with moisture in the air, or the container containing the curable composition may be heated to cure the composition.

The adhesive to be applied to the surface of the flame retardant-containing solid material 30 or to the peripheral surfaces of the openings 21, 22 may be any of various known adhesives conventionally used in the manufacture of wood composite materials, such as hot melt adhesives, vinyl acetate adhesives, epoxy adhesives, etc. Among these, it is preferable to use a vinyl acetate adhesive.
The flame retardant agent holding plates 10 can be bonded to each other using various known adhesives that are conventionally used in the manufacture of wood composite materials, such as aqueous polymer-isocyanate adhesives, resorcinol resin adhesives, resorcinol-phenol resin adhesives, melamine resin adhesives, melamine urea resin adhesives, urethane resin adhesives, epoxy resin adhesives, etc. Among these, resorcinol resin adhesives and resorcinol-phenol resin adhesives are preferred.

The fire-resistant wood composite material 1 can also be manufactured as follows.
First, the openings 21 and 22 are formed in the wood substrate 20 in which the openings 21 and 22 are not formed, with the positions of the center points 21a and 22a shifted in the first direction X and the second direction Y. Then, the openings 21 and 22 are filled with a hardening composition. The hardening composition is hardened to form a hardened product, that is, a flame retardant agent-containing solid material 30, to produce the flame retardant agent-holding plate 10. The flame retardant agent-holding plates 10 thus produced are laminated to produce the fire-resistant wood composite material 1. The openings 21 and 22 are both non-through and have bottoms 21b and 22b, so that even if the flame retardant agent-containing solid material 30 is in a liquid state when filled, the flame retardant agent-containing solid material 30 can be easily filled into the openings 21 and 22. There is no particular limitation on the method for hardening the hardening composition, and the above-mentioned methods can be used.

In the above-mentioned manufacturing method, the case where the wood substrate 20 is used without the openings 21, 22 formed therein is described, but it is also possible to use a wood substrate 20 in which the openings 21, 22 have been formed in advance in a separate process.

Next, a method for producing a fire-resistant wood composite material 1 having a compact as the flame-retardant agent-containing solid material 30 will be described.
First, the openings 21, 22 are formed in a wood substrate 20 that does not have the openings 21, 22, with the positions of the center points 21a, 22a shifted in the first direction X and the second direction Y. Separately, a powder containing a solid flame retardant is compacted into a shape substantially identical to the openings 21, 22 to obtain a compacted powder body, that is, a flame retardant-containing solid material 30. Thereafter, the openings 21, 22 are filled with the flame retardant-containing solid material 30 to produce a flame retardant-containing plate 10, in the same manner as when a cured product is used as the flame retardant-containing solid material 30, and the flame retardant-containing plates 10 are laminated together to produce a fire-resistant wood composite material 1.

The fire-resistant wood composite material 1 can also be manufactured as follows.
First, the openings 21, 22 are formed in a wood substrate 20 that does not have openings 21, 22 formed therein, with the positions of the center points 21a, 22a shifted in the first direction X and the second direction Y. Then, powder containing a solid flame retardant is filled into the openings 21, 22. The powder filled into the openings 21, 22 is then compressed and molded into a flame retardant-containing solid material 30 that is a compressed powder, thereby producing the flame retardant holding plate 10. Thereafter, the flame retardant holding plates 10 are stacked on top of each other to produce the fire-resistant wood composite material 1.

Even when a compressed powder is used as the flame retardant-containing solid material 30, a wood substrate 20 in which the openings 21, 22 have been formed in advance in a separate process may be used.

In the above-mentioned manufacturing method, when the flame retardant-containing solid is a cured product, the curable composition is placed in a container having approximately the same shape as the openings 21 and 22, and the curable composition is cured in the container to form the flame retardant-containing solid 30, which is a cured product. Alternatively, the curable composition may be placed in a cylindrical container having approximately the same diameter as the openings 21 and 22, and a cured product longer than the depth of the openings 21 and 22 may be formed. The cured product may then be cut to match the depth of the openings 21 and 22 to form the flame retardant-containing solid 30. A tapioca straw is preferable as the cylindrical container.

In addition to the solid flame retardant, the curable composition, and the curing catalyst, the curable composition may contain other components within a range that does not impair the effects of the present invention. Examples of other components contained in the curable composition include ultraviolet absorbers, anti-termite agents, and antioxidants. In addition to the solid flame retardant, the curable composition, and the curing catalyst, the compact may contain other components within a range that does not impair the effects of the present invention. Examples of other components contained in the compact include ultraviolet absorbers, anti-termite agents, and antioxidants.

In addition, when the fire-resistant wood composite material 1 has a plurality of flame retardant-containing solids 30, all of the flame retardant-containing solids 30 may be cured or pressed powder bodies, or some of the plurality of flame retardant-containing solids 30 may be cured and the rest may be pressed powder bodies. A fire-resistant wood composite material in which some of the plurality of flame retardant-containing solids 30 are cured and the rest are pressed powder bodies can be manufactured, for example, as follows.

First, the openings 21 and 22 are formed in the wood substrate 20 in which the openings 21 and 22 are not formed, with the positions of the center points 21a and 22a shifted in the first direction X and the second direction Y. Separately, a hardening composition is placed in a container having a shape substantially identical to that of the opening 21, and the hardening composition is hardened in the container to obtain a hardened solid material 30 containing a flame retardant agent. In addition, a powder containing a solid flame retardant is pressed into a shape substantially identical to that of the openings 21 and 22 to obtain a hardened solid material 30 containing a flame retardant agent. Next, each of the multiple openings 21 and 22 is filled with the hardened solid material 30 containing a flame retardant agent or the hardened solid material 30 containing a powder. In this way, a flame retardant agent holding plate 10 having both the hardened solid material 30 containing a flame retardant agent and the hardened solid material 30 containing a powder is manufactured. The flame retardant agent holding plates 10 manufactured in this way are stacked together to manufacture a fire-resistant wood composite material 1.

It is also possible to manufacture a fire-resistant wood composite material in which a portion of the multiple flame-retardant agent-containing solids 30 are hardened bodies and the remainder are green compacts, as described below.
First, the openings 21, 22 are formed in the wood substrate 20 where the openings 21, 22 are not formed, with the positions of the center points 21a, 22a shifted in the first direction X and the second direction Y. Then, the multiple openings 21, 22 are filled with a curable composition or a powder. Then, the curable composition is cured to form a flame retardant-containing solid 30, which is a cured product. The powder is also compacted to form a flame retardant-containing solid 30, which is a compact. In this way, a flame retardant-containing plate 10 is manufactured that has both the flame retardant-containing solid 30, which is a cured product, and the flame retardant-containing solid 30, which is a compact. The flame retardant-containing plates 10 manufactured in this way are stacked together to manufacture a fire-resistant wood composite material 1.

In the fire-resistant wood composite material 1 of this embodiment, the flame retardant holding plate 10 can be laminated in multiple layers and used as the fire-resistant wood composite material 1, or one flame retardant holding plate 10 can be used alone. A single flame retardant holding plate 10 is cut off by the flame retardant-containing solid material 30 filled in the openings 21 of the wood base material 20, so that when the flame retardant holding plate 10 burns, for example, it is difficult for large cracks to occur in the flame retardant holding plate 10. In addition, by using a solid material in a solid state as the flame retardant-containing solid material 30, it becomes easier to make the content of the flame retardant in the flame retardant holding plate 10 uniform and to make the content of the flame retardant in the flame retardant holding plate 10 the desired amount, so that it is possible to ensure stable fire resistance.

Furthermore, since the one-side opening 21 and the other-side opening 22 of the flame retardant agent holding plate 10 are non-through openings, when the flame retardant agent-containing solid material 30 is filled into the openings 21, 22, the flame retardant agent-containing solid material 30 is unlikely to jump out of the openings 21, 22. Therefore, when manufacturing the flame retardant agent holding plate 10, there is no need to manually repair the flame retardant agent holding plate 10 during manufacturing, and therefore it is easy to put the manufacturing process of the flame retardant agent holding plate 10 into an line.
In this manner, the flame retardant agent holding plate 10 can be easily manufactured.

In addition, because the one-side opening 21 and the other-side opening 22 are non-through openings, there is no need to provide a sealing layer on the one surface S1 side or the other surface S2 side of the wooden substrate 20 in order to prevent the flame-retardant-containing solid 30 from falling out of the one-side opening 21 or the other-side opening 22. Therefore, it is possible to prevent the thickness of the flame-retardant-holding plate 10 from becoming thicker than the thickness of the wooden substrate 20.
Furthermore, since the position of the center point 21a of the one-side opening 21 and the position of the center point 22a of the other-side opening 22 are offset in both the first direction X and the second direction Y, even if a portion of one surface S1 of the flame retardant chemical holding plate 10 that is not the one-side opening 21 burns and the combustion progresses downward in the thickness direction Z, the other-side opening 22 filled with the flame retardant chemical-containing solid 30 is located below that portion in the thickness direction Z, so that the combustion can be prevented from progressing downward in the thickness direction Z.
In this way, the flame retardant agent holding plate 10 can be both thin and fire resistant.
The flame retardant agent holding plate and fire-resistant wood composite material of the present invention can be used by being attached to, for example, a wall, a floor, or a ceiling.

5(a) to (c) show examples of preferred embodiments of the fire-resistant wooden structural material of the present invention. The fire-resistant wooden structural material of the present invention is a structural square timber used as a beam or pillar of a wooden building. The fire-resistant wooden structural material 7A shown in Figs. 5(a) and (b) is a structural square timber used as a pillar of a wooden building, and includes a load-bearing portion 8 and a fire-resistant coating layer 9.
5(a) shows a fire-resistant wooden structural member 7A having a load-bearing portion 8 and a fire-resistant coating layer 9. The fire-resistant wooden structural member 7A is a structural square timber used as a pillar of a wooden building.
The load-bearing portion 8 is a square timber, and its cross-sectional design is such that it is structurally safe against long-term loads such as fixed loads and live loads. Such cross-sectional designs are well known. The cross-sectional shape of the load-bearing portion 8 is rectangular, and the vertical and horizontal lengths of the load-bearing portion 8 in the cross-section of the fireproof wooden structural member 7A can be changed as appropriate depending on the shape or size of the beams or columns.

The fire-resistant coating layer 9 is arranged to cover the four side surfaces along the axial direction of the load support portion 8. Each of the fire-resistant coating layers 9 covering each side surface includes a flame retardant agent holding plate 10. More specifically, each of the fire-resistant coating layers 9 has a flame retardant agent holding plate laminated portion 40 in which a plurality of flame retardant agent holding plates 10 are laminated in the thickness direction. The flame retardant agent holding plate laminated portion 40 has a configuration similar to that of the above-mentioned fire-resistant wood composite material 1, and has a first direction and a second direction perpendicular to the first direction in a plan view. The fire-resistant coating layer 9 has a decorative layer 5 in addition to the flame retardant agent holding plate laminated portion 40. As the decorative layer 5, the same one as the decorative layer 5 of the above-mentioned fire-resistant wood composite material 1 can be used. Note that the fire-resistant coating layer 9 does not necessarily have to have the decorative layer 5, and may not have the decorative layer 5. In addition, each of the fire-resistant coating layers 9 may have only one flame retardant agent holding plate 10 instead of having the flame retardant agent holding plate laminated portion 40. In addition, a fire-resistant coating layer 9 having a flame-retardant agent holding plate laminate 40 and a fire-resistant coating layer 9 having only one flame-retardant agent holding plate 10 may coexist.

In FIG. 5(a), the portion 9e of the fire-resistant coating layer 9 extending from the portion where the load-supporting portion 8 is present is formed by a fire-resistant coating layer 9 having an L-shaped cross section, which is formed by joining the fire-resistant coating layers 9 located on both sides of a corner of the load-supporting portion 8. Also, the portion 9e of the fire-resistant coating layer 9 extending from the portion where the load-supporting portion 8 is present may be formed by extending the fire-resistant coating layer 9 along one side of the load-supporting portion 8 beyond the portion 9s where the load-supporting portion 8 is present, as shown in FIG. 5(b).

The fire-resistant coating layer 9 of the fire-resistant wooden structural material 7A is provided with a fire-retardant agent-holding plate 10 in which the wood substrate 20 is cut off by the fire-retardant agent-containing solid matter 30 filled in the openings 21 and 22. Therefore, when the fire-resistant coating layer 9 of the fire-resistant wooden structural material 7A burns, for example, the fire-resistant coating layer 9 is less likely to have large cracks, and the combustion is less likely to be transmitted to the load-supporting portion 8. In addition, the fire-resistant wooden structural material 7A is provided with a fire-retardant agent-holding plate 10 in which the position of the center point 21a of the opening 21 on one side and the position of the center point 22a of the opening 22 on the other side are offset in both the first direction X and the second direction Y. Therefore, when the fire-resistant coating layer 9 burns, for example, the combustion can be prevented from progressing downward in the thickness direction Z, and the combustion is less likely to be transmitted to the load-supporting portion 8.

Next, fire-resistant wooden structural material 7B, which is another embodiment of the fire-resistant wooden structural material of the present invention, will be described with reference to FIG. 5(c). Regarding fire-resistant wooden structural material 7B shown in FIG. 5(c), differences from fire-resistant wooden structural material 7A shown in FIGS. 5(a) and (b) will be described. Points that are not specifically described are the same as fire-resistant wooden structural material 7A, and the description of fire-resistant wooden structural material 7A applies as appropriate.

The fireproof wooden structural member 7B shown in Fig. 5(c) is a structural square timber used as a beam in a wooden building. In the fireproof wooden structural member 7B, the fireproof coating layer 9 is arranged so as to cover three side surfaces along the axial direction of the load-bearing portion 8. The load-bearing portion 8 of the fireproof wooden structural member 7B exists from the center of the cross section to the side surface on which the fireproof coating layer 9 is not formed. The side surface of the fireproof wooden structural member 7B on which the fireproof coating layer 9 is not formed may be covered on the upper side of the load-bearing portion 8 by placing, for example, a floor or the like thereon.
Although the preferred embodiment of the fire-resistant wood composite material of the present invention has been described above, the present invention is not limited to such an embodiment and can be modified as appropriate.
For example, in the fire-resistant wood composite material 1 of this embodiment, the positions of the center points 21a, 22a of the one-side opening 21 and the other-side opening 22 are offset in both the first direction X and the second direction Y, but the positions of the center points 21a, 22a of the one-side opening 21 and the other-side opening 22 may be offset in either the first direction X or the second direction Y. Even in this case, the same effect as that of the fire-resistant wood composite material 1 of this embodiment is achieved.

The first side openings 21 constituting the first side opening row 21R adjacent to each other in the first direction X do not necessarily have to have the same position of the center points 21a of the first side openings 21 in the second direction Y, and the positions of the center points 21a of the first side openings 21 in the second direction Y may be different. For example, the first side opening rows 21R adjacent to each other in the first direction X may be shifted by half a pitch or by two-thirds of a pitch in the second direction Y. The first side openings 21 constituting the second side opening row 21L adjacent to each other in the second direction Y may have different positions of the center points 21a of the first side openings 21 in the first direction X, and for example, the second side opening rows 21L adjacent to each other in the second direction Y may be shifted by half a pitch or by two-thirds of a pitch in the first direction X.

The other side openings 22 constituting the first other side opening row 22R adjacent to each other in the first direction X do not necessarily have to have the same position of the center points 22a of the other side openings 22 in the second direction Y, and the positions of the center points 22a of the other side openings 22 in the second direction Y may be different. For example, the first other side opening rows 22R adjacent to each other in the first direction X may be shifted by half a pitch or by two-thirds of a pitch in the second direction Y. The other side openings 22 constituting the second other side opening row 22L adjacent to each other in the second direction Y may have different positions of the center points 22a of the other side openings 22 in the first direction X, and for example, the second other side opening rows 22L adjacent to each other in the second direction Y may be shifted by half a pitch or by two-thirds of a pitch in the first direction X.

In this embodiment, the fire-resistant wood composite material 1 is a rectangular panel, the first direction X is parallel to one side of the panel, and the second direction Y is parallel to a side perpendicular to the first side. However, the first direction X may be defined to have an angle greater than 0 degrees and less than 90 degrees with respect to the side of the panel, and the direction perpendicular to the first direction X may be defined as the second direction Y.

The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited to these examples.

Example 1
A flame retardant holding plate having the same structure as the flame retardant holding plate 10 shown in FIG. 2 was manufactured. Specifically, a plywood having a vertical length of 400 mm, a horizontal length of 350 mm, and a thickness of 24 mm was used as the wood substrate. The one-side opening had a diameter of 10 mm and a depth of 14 mm, and the interval between the one-side openings in the first and second directions was 20 mm. The other-side opening had a diameter of 10 mm and a depth of 14 mm, and the interval between the other-side openings in the first and second directions was 20 mm. The one-side opening was filled with a curable composition having the following composition in a volume ratio of 100% to the opening, and then heated to 60° C. and cured for 6 hours to form a flame retardant-containing solid material, which is a cured product. The flame retardant-containing solid material of the other-side opening was also formed in the same manner as the flame retardant-containing solid material of the one-side opening. Two flame retardant holding plates manufactured in this way were stacked in the thickness direction. The two flame retardant holding plates were laminated so that the openings formed on the opposing surfaces did not overlap. A coniferous plywood board having a vertical length of 400 mm, a horizontal length of 350 mm, and a thickness of 48 mm was placed on one surface in the thickness direction of the laminated flame retardant holding plates. A resorcinol-based adhesive was used to bond the flame retardant holding plate and the plywood. The surfaces of the laminate of the flame retardant holding plate and the plywood produced in this way other than the surface on the flame retardant holding plate side were cured with a ceramic blanket and a gypsum board to prepare a test specimen of Example 1.

<Composition of Curable Composition>
Solid flame retardant: boric acid, 70% by mass
Curable compound: 3-glycidoxypropyltrimethoxysilane, 23% by mass
Curing catalyst: Aluminum-based curing catalyst (ACS, Hope Pharmaceutical Co., Ltd.), 7% by mass

Example 2
A test specimen of Example 2 was produced in the same manner as in Example 1, except that the depth of the one-surface opening and the other-surface opening was changed to 20 mm.

(Combustion test 1)
The test specimens obtained in Examples 1 and 2 were placed in a combustion test furnace. The test specimens were arranged so that the longitudinal direction of the surface on the side of the flame retardant agent holding plate coincided with the vertical direction. In the test specimen, the surface on the side of the flame retardant agent holding plate was the heating surface that was heated on one side. Then, the test specimens were heated for one hour by standard heating according to ISO834-1, which assumes a normal fire, and after the heating, the test specimens were left to cool in the furnace for four hours.
In this case, in Examples 1 and 2, the temperature change was measured at the positions where the depth from the heating surface was 12 mm, 24 mm, 36 mm, and 48 mm at the upper boundary of the two boundary lines when the heating surface was divided into three equal parts in the vertical direction (respective positions are indicated as upper 12, upper 24, upper 36, and upper 48 in Figs. 6 and 7), and at the positions where the depth from the heating surface was 12 mm, 24 mm, 36 mm, and 48 mm at the lower boundary of the two boundary lines (respective positions are indicated as lower 12, lower 24, lower 36, and lower 48 in Figs. 6 and 7), and the temperature change over time at each position was confirmed. The temperature change over time at each position in Example 1 is shown in Fig. 6, and the temperature change over time at each position in Example 2 is shown in Fig. 7.

In Examples 1 and 2, the burning was confirmed, and it was confirmed that the board had a one-hour fire resistance. Specifically, in both Examples 1 and 2, the temperatures at the positions 36 mm and 48 mm deep from the heating surface did not reach 250°C, which is the ignition temperature of wood. In other words, of the two stacked flame retardant agent holding plates, the flame retardant agent holding plate on the opposite side to the heating surface was not burning. In addition, at the positions 12 mm and 24 mm deep from the heating surface, the temperature gradually decreased after the end of heating (after one hour from the start of heating), and no re-rise in temperature was observed, so it can be seen that the burning did not continue and the burning had stopped.
The carbonization depth was 29 mm in Example 1 and 26 mm in Example 2. This shows that by increasing the depth of the one-side openings or the other-side openings and increasing the height of the flame retardant-containing solid material, the fire resistance of the fire-resistant wood composite material can be improved without increasing the number of layers of the flame retardant-holding plate.

Example 3
A laminate consisting of two flame retardant agent holding plates manufactured in the same manner as in Example 1 was adhered to the four sides along the height direction of a cedar pillar measuring 120 mm in length, 120 mm in width, and 1000 mm in height to prepare a test specimen for Example 3. As in Example 1, the two flame retardant agent holding plates were stacked such that the openings formed on the opposing surfaces did not overlap.

Example 4
A test specimen for Example 4 was produced in the same manner as in Example 3, except that the two flame retardant chemical holding plates were laminated so that the openings formed on the opposing surfaces of each plate completely overlapped each other (see FIG. 4).

(Combustion test 2)
The test specimens obtained in Examples 3 and 4 were placed in a test furnace in an upright position so that the height direction was aligned with the vertical direction, and each of the four sides was heated for one hour using the ISO 834-1 standard heating method assuming a normal fire. After heating, the specimens were allowed to cool in the furnace for four hours. At that time, the temperature changes were measured at the center of the height direction of the test specimens, at the four corners of the cross section of the cedar column, and at the center of each of the four sides of the cross section. The positions where the temperature changes were measured are shown by black and white dots in Figures 8 and 9. In Figures 8 and 9, the black dots indicate the four corners of the cross section of the cedar column, and the white dots indicate the center of each of the four sides of the cross section. The results of measuring the temperature changes at each position are shown in Figures 10 and 11, respectively.

In Examples 3 and 4, the fire was stopped, and it was confirmed that the material had one-hour fire resistance. Specifically, in Examples 3 and 4, the temperature at all positions where the temperature change was measured did not reach 250°C, which is the ignition temperature of wood. In other words, the combustion did not reach the cedar pillar. Since the fire was stopped in both Examples 3 and 4, it can be seen that in the fire-resistant wood composite material of the present invention, the positional relationship between the laminated flame retardant agent holding plates can be arbitrarily set. In addition, when comparing Examples 3 and 4, it can be seen that Example 3 has less temperature variation and a lower maximum temperature, and therefore Example 3 has superior fire resistance to Example 4. In Example 3, the two flame retardant chemical holding plates are stacked so that the openings formed on the opposing surfaces do not overlap, and in Example 4, the two flame retardant chemical holding plates are stacked so that the openings formed on the opposing surfaces completely overlap. When the two flame retardant chemical holding plates are stacked so that the openings formed on the opposing surfaces partially overlap, it is expected that the fire resistance performance will be between Example 3 and Example 4.

REFERENCE SIGNS LIST 1 Fire-resistant wood composite material 10 Flame retardant agent-holding plate S1 One side of flame retardant agent-holding plate S2 Other side of flame retardant agent-holding plate 20 Wood base material 21 Opening on one side 22 Opening on other side 25 Opening overlap area 30 Solid material containing flame retardant agent 5 Decorative layer 7 Fire-resistant wooden structural material 8 Load-bearing portion 9 Fire-resistant coating layer 40 Flame retardant agent-holding plate laminate portion X First direction Y Second direction Z Thickness direction

Claims (8)

A flame retardant agent holding plate used for forming a fire-resistant coating layer,
A first direction and a second direction perpendicular to the first direction,
The present invention comprises a wood base material having non-through holes on each of one side and the other side, and a solid material containing a flame retardant agent filled in each of the holes,
the opening on one surface side and the opening on the other surface side have center points offset from each other in a first direction, a second direction, or both directions;
The opening on one surface side and the opening on the other surface side do not overlap in a plan view of the flame retardant agent holding plate,
the flame retardant chemical holding plate has an aperture overlap region in a central region in a thickness direction thereof, in which both a part of the aperture on one surface side and a part of the aperture on the other surface side are present;
The flame retardant-containing solid material is either or both of a cured product of a curable composition containing a solid flame retardant and a compact containing a solid flame retardant;
The cured product of the curable composition is a product that is filled into the openings in a paste state and then cured, or a product that is filled into the openings in a solid state,
A flame retardant agent holding plate that has not been impregnated with a liquid treatment agent . 2. The flame retardant agent holding plate according to claim 1, wherein the cured product of the curable composition is filled in the openings in a solid state . The flame retardant agent-containing solid material is a cured product of a curable composition containing a solid flame retardant, and the curable composition contains the solid flame retardant, a curable compound, and a curing catalyst. The flame retardant agent-holding plate according to claim 1 or 2. The flame retardant agent holding plate according to any one of claims 1 to 3, wherein an adhesive is applied to a surface of the flame retardant agent-containing solid or to a peripheral surface of the opening in which the flame retardant agent-containing solid is accommodated. The flame retardant agent holding board according to any one of claims 1 to 4 , wherein the wood base material is a plywood made of a laminate of a plurality of veneers. A fire-resistant wood composite material having a structure in which a plurality of flame retardant agent holding plates are laminated,
A fire-resistant wood composite material, wherein the flame retardant agent-holding plate is the flame retardant agent-holding plate according to any one of claims 1 to 5. A fire-resistant wooden structural member comprising a load-bearing portion made of a square timber and a fire-resistant coating layer covering three or four axial sides of the load-bearing portion,
A fire-resistant wooden structural material, wherein each of the fire-resistant coating layers covering each of the side surfaces includes the flame retardant agent holding plate according to any one of claims 1 to 5. The fire-resistant wooden structural material according to claim 7, wherein each of the fire-resistant coating layers has a flame-retardant agent-holding plate laminate section in which a plurality of flame-retardant agent-holding plates according to any one of claims 1 to 5 are laminated in the thickness direction.

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