JP2004155161A - Woody fiber accumulated and laminated board and gage table of pachinko game stand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a woody fiber accumulated and laminated board improved in a drivability of a nail and keeping property of the nail driven, and also can be produced at a low cost, and a gage table of a pachinko game stand made of the woody fiber accumulated and laminated board. <P>SOLUTION: The woody fiber accumulated and laminated board is made by binding woody fibers with a binder and formed to a united body. The board has a mean density of the whole board in a range of 0.69-0.76 g/cm<SP>3</SP>and has a surface layer with a thickness of 2.5 mm or less formed on the surface part thereof and with a density of 1.0 g/cm<SP>3</SP>or more. The gage table of the pachinko game stand has a thickness in a range of 15-25 mm. <P>COPYRIGHT: (C)2004,JPO

Description

【００２９】
表１に示した結果のうち、実施例１〜５及び比較例１〜２について、密度が１．０ｇ／ｃｍ^３以上である表面層の厚さｔ_２と、釘打ち力との関係をグラフ化して、図２に示す。図２からわかるように、表面層の密度が１．０ｇ／ｃｍ^３以上であっても、本発明に係る実施例１〜５においては、良好な釘打ち性が得られることがわかった。また、表面層の厚さｔ_２が２．５ｍｍ以下であると、釘打ち力が０．８２ｋＮ以下となり釘打ち性が合格となった。
また、釘打ち力と釘保持力の関係をグラフで表わすと、図３のようになった。図３からわかるように、釘打ち力と釘保持力の関係は、良好な釘保持力である４０ｋｇｆ以上を得るためには、釘打ち力が大きくなるという相反する関係にあり、双方が良好な木質繊維集積板を得ることは困難である。しかしながら、実施例１〜５のように、密度が１．０ｇ／ｃｍ^３以上である表面層の厚さが２．５ｍｍ以下であり、全体密度が０．６９〜０．７６ｇ／ｃｍ^３の範囲であると、釘打ち性、釘保持力共に優れている木質繊維集積板を得られることがわかった。
また、釘保持力と全体密度の関係を図４に示す。図４からわかるように、全体密度が０．６９ｇ／ｃｍ^３以上であると、釘保持力が４０ｋｇｆ以上となり釘保持力が合格となった。
なお、実施例６のようにバインダーとしてメラミン樹脂のみを用いた場合にも、釘打ち性、釘保持力共に合格となった。ただし、全体密度が同じである実施例３と実施例６を比較すると、バインダーとしてはメラミン樹脂とＭＤＩとを用いた実施例３の方が釘保持力に優れる傾向にあるため、バインダーとしてはメラミン樹脂とＭＤＩとを用いることが好ましいことがわかった。
【００３０】
【発明の効果】
以上説明したように、本発明の木質繊維集積板は、釘打ち性及び釘保持力に優れ、安定した性能を有している。従って、本発明の木質繊維集積板は、パチンコ台のゲージ盤を製造するために好適に用いられる。
【図面の簡単な説明】
【図１】本発明の木質繊維集積板の一実施形態を示す断面図である。
【図２】実施例にかかる木質繊維集積板の表面層の厚さと釘打ち力との関係を示すグラフである。
【図３】実施例にかかる木質繊維集積板の釘保持力と釘打ち力との関係を示すグラフである。
【図４】実施例にかかる木質繊維集積板の釘保持力と全体密度との関係を示すグラフである。
【符号の説明】
１・・木質繊維集積板、２・・表面層、３・・芯層、４・・木質繊維、５・・バインダー[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wood fiber integrated board and a gauge board for a pachinko machine.
[0002]
[Prior art]
A wood fiber integrated board formed by integrally bonding wood fibers with a binder is used for various applications, and one of the uses is a gauge board of a pachinko machine. The gauge board of the pachinko machine refers to a front plate for guiding the flow of the pachinko balls. When using a wood fiber accumulation board as a gauge board of a pachinko machine, it is desired that nails are easy to strike and that the holding power of the nails is good.
However, among the wood fiber integrated boards, in a commonly used MDF (medium density wood fiber integrated board) or the like, a layer having a relatively high density, a so-called bedrock layer, is formed on the surface of the molded article due to the characteristics of press molding. If the rock layer is hard, the nails cannot be hit, or the nails may be bent when hit. If the density of the bed layer of the wood fiber accumulation board or the average density of the entire wood fiber accumulation board is reduced so that the nail can be easily hit, the strength of the entire wood fiber accumulation board and the holding power of the nail decrease. As described above, it is very difficult to improve both the ease of nailing and the holding power of nails, and as a gauge board for a pachinko machine, plywood using precious wood resources such as lawan merantee is exclusively used. I was relying on.
[0003]
In order to solve the above problems, there has been proposed a wood fiber integrated board having a density distribution within a certain range and having no high density bedrock layer (see Patent Document 1). Specifically, a range density distribution of ^{0.52g / cm 3 ~1.0g / cm 3} , or density does not exist 0.80 g / cm ³ or more layers, or thickness 2mm in the surface portion There are proposed wood fiber accumulation boards that are less than.
According to Patent Document 1, when a layer having a density of 1.0 g / cm ³ or more is present, particularly when a layer having a density of 0.8 g / cm ³ or more and a thickness of more than 2 mm is present on the surface portion, It was said that the nail would be harder to hit and the nail would be easier to bend.
[0004]
[Patent Document 1]
JP 2000-141324 A
[Problems to be solved by the invention]
However, when the wood fiber integrated board described in Patent Document 1 was manufactured and evaluated, it was found that there was a variation in nailing performance and nail holding force, and there was a problem in obtaining stable performance.
The present invention has been made in view of the problems of the related art, and has excellent nailing properties, excellent nail holding power, stable performance, and a wood fiber integrated board that can be manufactured at low cost, and An object of the present invention is to provide a gauge board of a pachinko machine made of the wood fiber integrated board.
[0006]
[Means for Solving the Problems]
The inventors of the present invention have conducted intensive studies to solve the above-described problems, and as a result, by forming a rock layer having a density of 1.0 g / cm ³ or more with a limited thickness, excellent nailing properties and nails are obtained. It has been found that holding power can be obtained. That is, the thickness of the layer having a density of 1.0 g / cm ³ or more is 2.5 mm or less of the surface portion, and the average density of the entire wood-based integrated board is in the range of 0.69 to 0.76 g / cm ³ . The inventors have found that the above-mentioned problems can be solved, and have completed the present invention.
That is, the present invention relates to a wood fiber integrated board in which wood fibers are combined with a binder and integrally formed, the overall average density is in a range of 0.69 to 0.76 g / cm ³ , and A wood fiber integrated board having a surface layer having a thickness of 2.5 mm or less and a density of the surface layer being 1.0 g / cm ³ or more.
Further, the present invention is the gauge board of a pachinko machine comprising the wood fiber accumulation board, wherein the wood fiber accumulation board has a thickness in a range of 15 to 25 mm.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that this embodiment is for explaining the gist of the present invention, and does not limit the present invention unless otherwise limited.
[0008]
FIG. 1 is a sectional view showing one embodiment of a wood fiber integrated board according to the present invention. The wood fiber accumulation board 1 is formed by integrally forming wood fibers 4 joined by a binder 5. This wood fiber integrated board 1 is formed of a core layer 3 and surface layers 2 and 2 on both surface sides of the core layer 3, and the surface layer 2 has a density of 1.0 g / cm ³ or more, the thickness _{t 2} is 2.5mm or less. Furthermore, the average density of the whole wood fiber integrated board 1 is in the range of 0.69 to 0.76 g / cm ³ .
[0009]
The thickness _{t 1} of the wood fiber stacking plate 1, 15 to 25 mm, preferably 17～20Mm. The thickness _{t 3} of the core layer 3 is preferably 12 to 18 mm.
The thickness _{t 2} of the surface layer 2 are 2.5mm or less, further, is preferably 2.2mm or less. If the thickness t ₂ of the surface layer 2 is at 2.5mm or less, good nailability and nail holding power is obtained. The thickness _{t 2} of the surface layer 2 are 0.7mm or more, preferably more less than 1.0mm. If the thickness t ₂ of the surface layer 2 is less than 0.7 mm, undesirably it could no made for it to have sufficient nail holding power.
[0010]
The density of the surface layer 2 is preferably 1.0 g / cm ³ or more. When the density of the surface layer 2 is 1.0 g / cm ³ or more, the nail holding force of the wood fiber integrated board 1 is improved. Further, the density of the surface layer 2 is preferably 1.3 g / cm ³ or less. When the density of the surface layer 2 is 1.3 g / cm ³ or less, the nailing property of the wood fiber integrated board 1 is improved.
The average density of the entire wood fiber integrated board 1 is in the range of 0.69 to 0.76 g / cm ³ , and preferably 0.70 to 0.74 g / cm ³ . When the density of the surface layer 2 and the average density of the wood fiber integrated board 1 as a whole are within the above ranges, the nailing properties of the wood fiber integrated board 1 are improved, and the nail holding force is also good.
[0011]
As the wood fiber 4 for manufacturing the wood fiber accumulation board 1 of the present invention, wood such as softwood or hardwood is chipped with a chipper and defibrated is used.
The size of the wood fiber 4 is preferably 0.1 to 10 mm in length and 2 to 300 μm in diameter (thickness). Further, as described above, the wood fiber 4 having a length of 0.1 to 10 mm and a diameter of 2 to 300 μm accounts for about 70% of the total amount of the wood fiber 4 used for manufacturing the wood fiber integrated board 1. %, Preferably about 85% by weight or more.
If the length of the wood fiber 4 is longer than 10 mm or the thickness is larger than 300 μm, it is difficult to drive the nail straight into the wood fiber accumulation plate 1, and the nail holding force and the nail driving property are not uniform. When the length of the wood fiber 4 is 0.1 to 10 mm and the length is 0.1 to 10 mm, it becomes easy to strike the nail straight into the wood fiber accumulation board 1 and has a good nail holding force. Can be obtained. The length and diameter of the wood fiber can be determined by microscopic observation.
[0012]
The wood fiber 4 can be manufactured as follows. That is, wood such as hardwood or conifer is made into chips by a chipper, and the obtained chips are defibrated. For fibrillation, a method of steaming with high-pressure steam at about 150 ° C. and then fibrillating with a disc refiner is used. The wood fibers 4 obtained by defibration can be used after being acetylated, but may be used without being acetylated.
ADVANTAGE OF THE INVENTION According to this invention, since the thickness and density of a surface layer are prescribed | regulated, and the whole average density is prescribed | regulated in a fixed range, the wood fiber accumulation board which has favorable nailing property and nail holding power is obtained. Therefore, even if the wood fibers 4 are not acetylated, it is possible to obtain a wood fiber accumulation board excellent in nailing properties, nail holding power, and the like.
When the weight of the wood fibers 4 (however, absolutely dry weight) is about 70% by weight, preferably 85% by weight or more in the total weight of the wood fiber accumulation board 1, the wood fibers having excellent nailing properties and nail holding power are provided. An integrated board 1 can be obtained.
[0013]
As the binder 5 for binding the wood fibers 4, for example, a thermosetting resin can be used. Examples of the thermosetting resin include urea resin, melamine resin, phenol resin, polyurethane resin, epoxy resin, diallyl phthalate resin, polymethylene diphenyl diisocyanate (hereinafter, referred to as MDI), and the like. These binders 5 may be used alone or as a mixture of two or more.
Among these binders, it is preferable to use a melamine resin and MDI. By using the melamine resin and MDI in combination, a good nail holding force can be obtained.
[0014]
The amount of the binder 5 to be used is preferably 5 to 25 parts by weight in terms of solid content based on 100 parts by weight of the absolute dry weight of the wood fiber 4. If the amount of the binder 5 is less than 5 parts by weight, it becomes difficult to combine the wood fibers 4 and form them, and the nail holding force is weak and the bending strength is weak. Even if the amount of the binder 5 exceeds 25 parts by weight, there is no particular improvement effect, and the use amount of the binder 5 is excessive, so that the cost increases, which is not preferable.
When melamine resin and MDI are used as binder 5, MDI is preferably used in a proportion of 3 to 80 parts by weight, preferably 10 to 65 parts by weight, based on 100 parts by weight of melamine resin. If the MDI is less than 3 parts by weight, the water resistance of the wood fiber integrated board 1 tends to decrease, and if it is more than 80 parts by weight, the releasability is disadvantageous.
[0015]
Further, when melamine resin and MDI are used as the binder 5, it is preferable to separately apply the melamine resin and MDI to the wood fiber 4.
When the melamine resin and the MDI are separately applied, the melamine resin is in a ratio of 5 to 25 parts by weight, preferably 6 to 20 parts by weight, based on 100 parts by weight of the absolutely dry weight of the wood fiber 4. The proportion is preferably 0.5 to 20 parts by weight, more preferably 1 to 15 parts by weight. In this case, the order of applying the melamine resin and the MDI is arbitrary.
[0016]
Next, a method for manufacturing the wood fiber integrated board 1 of the present invention will be described.
First, by mixing the wood fiber 4 and the binder 5 as described above and attaching the binder 5 on the surface of the wood fiber 4, the wood fiber material for integrally forming the wood fiber integrated board 1 is formed. Prepare. The mixing method of the wood fiber and the binder is arbitrary, but for example, a method of applying by a spray method can be adopted. That is, a method is preferable in which the wood fibers whose size is adjusted are put into a rotating drum rotating at a low speed, and a binder is spray-coated on the wood fibers when the wood fibers fall naturally in the rotating drum.
[0017]
Next, the wood fiber material obtained as described above is hot-pressed to obtain the wood fiber integrated board 1 in which the wood fibers 4 are bonded by the binder 5. By the hot pressing, the binder 5 in the wood fiber material reacts and hardens, and the wood fiber 4 is bound by the hardened material of the binder 5. The hot pressing temperature is about 150 to 230 ° C, preferably 180 to 220 ° C, depending on the kind of the binder. The time for performing the hot pressing is 8 to 40 sec / mm, more preferably 10 to 25 sec / mm, with respect to the forming thickness of 1 mm.
If the thickness of the wood fiber integrated board obtained by hot pressing is about 15 to 25 mm, the average density of the whole is in the range of 0.69 to 0.76 g / cm ³ , and the thickness of 2.5 mm A wood fiber integrated board 1 having the following surface layer and having a density of the surface layer of 1.0 g / cm ³ or more is easily obtained. Such a wood fiber integrated board 1 is excellent in nailing property and nail holding force.
When a surface layer having a density of 1.0 g / cm ³ or more is formed on the surface over a thickness of 2.5 mm or more, the surface layer may be cut and removed with a sander or the like to obtain a wood fiber integrated board. 1 can be obtained.
As described above, the wood fiber integrated board 1 of the present embodiment can be manufactured easily and at low cost.
[0018]
Wood fiber stacking plate 1 of this embodiment is in the range the average density of the total of 0.69~0.76g / cm ^3, a thickness of 2.5mm density in the surface portion is 1.0 g / cm ³ or more Since it has the following surface layer, it has excellent nailing properties. That is, the nail is easy to hit and can be hit straight without bending. This nailing property can be numerically evaluated by using the “nail driving force”. The nailing force refers to the resistance at the time of nailing, and the smaller the numerical value, the less the need to apply excessive force, indicating that the nail is easier to nail straight. This nailing force is preferably 0.82 kN or less, and more preferably 0.72 kN or less.
In addition, the wood fiber integrated board 1 of the present embodiment has excellent nail holding power, and the nail that has been hit hardly comes off the board. The greater the value of the nail holding force, the higher and superior the nail holding force, and it is preferably 40 kgf or more, and more preferably 45 kgf or more.
[0019]
Although not included in this embodiment, a cell decorative sheet (not shown) having a thickness of, for example, 0.3 to 0.7 mm may be attached to one surface of the wood fiber accumulation board of the present invention. The cell decorative sheet is obtained by laminating paper on one side of a celluloid film, for example. Furthermore, when the cell decorative sheet is pasted on one side, the surface and the back face are asymmetric, and the cell decorative sheet pasted wood fiber accumulation board is likely to be warped and twisted due to a change in humidity or the like. The backsheet can be integrated on at least one side, preferably on both sides, of the layer joined by the binder. In this case, the back sheet is integrated on at least the side opposite to the side on which the cell decorative sheet is affixed, on the surface of the wood fiber accumulation board. An adhesive may be applied to the back sheet in advance, and the back sheet may be bonded to the pre-formed wood fiber accumulating board 1 to integrate the back sheet with the wood fiber accumulating board 1. It is preferable that the back sheet is integrated with the layer of the wood fibers 4 bonded by the binder 5 by superimposing the back sheet on the fiber 4 and performing hot pressing.
[0020]
As the back sheet, paper such as Japanese paper or non-woven fabric such as vinylon non-woven fabric and glass non-woven fabric is used. The use of Japanese paper as the back sheet is preferable because the binder is easily impregnated into the Japanese paper at the time of hot pressing, so that the wood fiber accumulation board and the back sheet (Japanese paper) are firmly adhered to each other. . A preferred Japanese paper is a paper made from gin skin fibers such as mulberry, mitsumata, and gambi, and using paper thread at the time of papermaking. Basis weight as the back sheet preferably has from about 20 to 200 g / ^{m 2,} a basis weight to hardly suppress warpage is less than 20 g / ^{m 2,} not preferable because cost increases exceeds 200 g / ^{m 2.}
[0021]
As described above, the wood fiber accumulation board 1 of the present embodiment has a good nailing property and an excellent nail holding force, and therefore is suitable for use as a gauge board of a pachinko machine that needs to be nailed. The thickness _{t 1} is 15 to 25 mm, preferably is wood fiber stacking plate 1 is 17～20Mm, to produce a pachinko machine gauge plate is particularly useful. When such a wood fiber accumulation board 1 is nailed with an automatic nailing machine, the nail can be driven straight and evenly, and the nail is hard to be pulled out of the wood fiber accumulation board 1. Such a gauge board of a pachinko machine can be manufactured by providing a through hole in the wood fiber accumulation board of the present invention and nailing.
[0022]
【Example】
Hereinafter, examples of the present invention will be described, but the scope of the present invention is not limited to these examples.
(Example 1)
The diameter is 0. A wood fiber having a length of about 1 to 1.0 mm and a length of about 0.2 to 50 mm is pulverized using a power mill (P-5) (manufactured by Dalton Co., Ltd.), and has a length of 0.1 mm or more and 10 mm or less. Wood fibers having a diameter in the range of 2 to 300 μm were obtained.
[0023]
Next, the obtained wood fiber was put into a rotating drum rotating at a low speed, and a binder was spray-applied when the wood fiber dropped naturally in the drum. The coating amount of the binder is 10 parts by weight of melamine resin solid content and 5 parts by weight of crude polymethylene diphenyl diisocyanate (crude MDI: manufactured by Sumitomo Bayer Urethane Co., Ltd.) based on 100 parts by weight of the dry wood fiber. Was.
[0024]
Next, the wood fiber coated with the binder was formed using a forming machine to obtain a wood fiber material (mat-like material, thickness of about 400 mm). Japanese paper (the basis weight of the Japanese paper was 30 g / m ² ) was placed on both sides of the mat-like material. The mat-like material and the Japanese paper were superimposed on each other and press-formed between hot plates of a press to obtain a wood fiber integrated board 11 having back sheets attached to both surfaces. The hot pressure conditions were a hot plate temperature of 180 ° C., a press pressure of 20 to 30 kgf / cm ² , and a pressing time of 20 minutes. The backsheet-attached wood fiber assembly board 11 is one in which Japanese paper (back sheet) is integrated at both sides of the wood fiber assembly board 1 obtained by binding the wood fibers 4 with the binder 5 at the time of hot pressing. Was. The size of the wood fiber integrated board 11 was 500 mm wide × 450 mm long × 19 mm thick.
[0025]
When the obtained backsheet-attached wood fiber accumulation board 11 was nailed with an automatic nailing machine, the nail was hit straight. The nailing force at this time was 0.53 kN. In addition, when the nail holding force of the driven nail was measured by a pull-out test, the average value was 40 kgf. The minimum value of the nail holding force was 36 kgf, the maximum value was 48 kgf, and the number of measured nails was 10. Furthermore, the density distribution in the thickness direction of one portion of the wood fiber integrated board was measured using a density distribution measuring device for measuring the density distribution (density profile, density profile) in the thickness direction. The overall density of one portion of the wood fiber integrated board was 0.69 g / cm ³ , and the thickness t ₂ of the surface layer having a density of 1.0 g / cm ³ or more was 1 mm.
Note that a standard ATR Density Profiling Type DPM201 manufactured by ATR (Germany) was used as a density distribution measuring device in the thickness direction.
[0026]
(Examples 2 to 6, Comparative Examples 1 and 2)
In Examples 2 to 5 and Comparative Examples 1 and 2, the total density and the thickness of the surface layer were changed according to the same method as in Example 1 except that the amount of wood fiber input and the composition and amount of the binder were changed. It is to produce a different wood fiber stacking plate of t _2. In Example 6, a wood fiber integrated board was manufactured in the same manner as in Example 1 except that the resin contained in the binder was changed.
The nailing force and nailability of the wood fiber integrated boards according to Examples 2 to 6 and Comparative Examples 1 and 2 were measured in the same manner as in Example 1. Also, the thickness t ₂ of the overall density and surface layer was measured in the same manner.
[0027]
Table 1 summarizes the measurement results of the wood fiber integrated boards according to Examples 1 to 6 and Comparative Examples 1 and 2 regarding the nailing property, the nail holding power, the overall density, and the thickness of the surface layer. In Table 1, melamine / MDI indicates that melamine resin and crude polymethylene diphenyl diisocyanate were used, and melamine indicates that melamine resin was used as a binder to produce a wood fiber integrated board. ing.
Also, in Table 1, the nailing performance is indicated by a circle when the nailing force is 0.82 kN or less, and is judged as acceptable, and when the nailing force is greater than 0.82 kN, it is indicated as an unacceptable mark. Here, the nailing force was measured by inserting a nail having a diameter of 1.85 mm and a length of 32 mm into a 50 mm x 50 mm plate at a maximum compression load of 50 mm / min. The nail holding force was determined by measuring the pull-out strength of a nail after driving a pachinko nail into a 50 × 50 mm square base plate. The strength was measured in accordance with JIS A5905-1994, 5.13 wood screw holding force test method, and 5.14 nail reverse pull resistance test method. As a gauge board of a pachinko machine requiring durability, it is desirable that the nail holding force is about 40 kgf, preferably 45 kgf. It was indicated by x mark as reject.
[0028]
[Table 1]

[0029]
Of the results shown in Table 1, the graph for Examples 1-5 and Comparative Examples 1-2, of the surface layer density is the 1.0 g / cm ³ or more and a thickness _{t 2,} the relationship between the nailing force This is shown in FIG. As can be seen from FIG. 2, even when the density of the surface layer was 1.0 g / cm ³ or more, in Examples 1 to 5 according to the present invention, it was found that good nailing properties were obtained. If the thickness _{t 2} of the surface layer is 2.5mm or less, nailing force nailability becomes less 0.82kN became acceptable.
FIG. 3 is a graph showing the relationship between the nailing force and the nail holding force. As can be seen from FIG. 3, the relationship between the nailing force and the nail holding force is in a conflicting relationship that the nailing force increases in order to obtain a good nail holding force of 40 kgf or more. It is difficult to obtain wood fiber accumulation boards. However, as in Examples 1 to 5, the thickness of the surface layer having a density of 1.0 g / cm ³ or more is 2.5 mm or less, and the overall density is in a range of 0.69 to 0.76 g / cm ³ . Thus, it was found that a wood fiber integrated board having excellent nailing properties and nail holding power could be obtained.
FIG. 4 shows the relationship between the nail holding force and the overall density. As can be seen from FIG. 4, when the overall density was 0.69 g / cm ³ or more, the nail holding force was 40 kgf or more, and the nail holding force passed.
In addition, when only the melamine resin was used as the binder as in Example 6, both the nailing property and the nail holding force were acceptable. However, comparing Example 3 with Example 6 having the same overall density, Example 3 using melamine resin and MDI as the binder tends to have better nail holding power. It has been found preferable to use a resin and MDI.
[0030]
【The invention's effect】
As described above, the wood fiber accumulation board of the present invention has excellent nailing properties and nail holding power, and has stable performance. Therefore, the wood fiber accumulation board of the present invention is suitably used for manufacturing a gauge board of a pachinko machine.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing one embodiment of a wood fiber accumulation board of the present invention.
FIG. 2 is a graph showing the relationship between the thickness of the surface layer of the wood fiber integrated board and the nailing force according to the example.
FIG. 3 is a graph showing a relationship between a nail holding force and a nail driving force of the wood fiber accumulation board according to the example.
FIG. 4 is a graph showing the relationship between the nail holding force and the overall density of the wood fiber integrated board according to the example.
[Explanation of symbols]
1. Wood laminated board, 2. Surface layer, 3. Core layer, 4. Wood fiber, 5. Binder

Claims (3)

A wood fiber integrated board formed by integrally bonding wood fibers with a binder, and having an average density of 0.69 to 0.76 g / cm ³ and a thickness of 2.5 mm on the surface. A wood fiber integrated board having the following surface layer, wherein the density of the surface layer is 1.0 g / cm ³ or more. The wood fiber integrated board according to claim 1, wherein the binder contains a melamine resin and polymethylene diphenyl diisocyanate. The wood fiber accumulation board according to claim 1 or 2, wherein the thickness is in the range of 15 to 25 mm.

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