JP2002145653A - Cemented chip board and cemented chip laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cemented chip board the shrinkage of which is inhibited even in such a state that flame is directly applied to the board over a long period of time and accordingly, which has excellent fire resistance efficiency. SOLUTION: This cemented chip board consists of cement, wood chips and vermiculite having a 0.5-5.0 mm average particle size, a 32-40% SiO2 content and a 9-16 wt.% ignition loss, wherein the vermiculite content in the resulting cemented chip board is 0.5-10 wt.% on the basis of the weight of the board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood chip cement board and a wood chip cement laminate used as a building material for an outer wall or the like.

[0002]

2. Description of the Prior Art Conventionally, wood chip cement boards and wood chip cement laminates are mainly used for building exterior walls, etc. because they have both fire resistance and water resistance of hardened cement and workability and nailing properties of wood chips. Has been, for example, after mixing the cement composition and wood chips and water containing Portland cement as a main component, the mixture is supplied to a mold, and shaped into a predetermined shape by heating under pressure, It is manufactured by curing.

[0003] When such a wood chip cement board or a wood chip cement laminate is used for an outer wall of a building, etc., although a certain degree of fire prevention performance is exhibited, the fire resistance for a long time is deteriorated by cracks due to shrinkage of the wood chip during combustion. Has been pointed out. For this reason, Japanese Unexamined Patent Application Publication No.
Patent No. 605, pp. 157-181, 1988. A hydrate that treats a piece of wood with a flame retardant to suppress the burning of the piece of wood as described in JP-A-7-317201, and releases crystallization water when heated as described in JP-A-7-317201. It has been proposed to suppress a rise in temperature by mixing crystals or the like.

[0004]

However, when the wood pieces are subjected to the flame-proof treatment as in the former case, the burning speed of the wood pieces is reduced and the fire resistance time is prolonged, but the amount of shrinkage during the burning of the wood pieces cannot be suppressed. However, there is a problem that long-time fire resistance cannot be imparted.

[0005] When the hydrate crystals are mixed as in the latter case, the refractory time is extended until the water of crystallization of the hydrate crystals is exhausted, but it is difficult to suppress the occurrence of cracks due to shrinkage during burning of the wood chips. There is a problem that is.

The present invention has been made in view of the above problems, and provides a wood chip cement board and a wood chip cement laminate which are excellent in fire resistance by suppressing shrinkage even in a long-time flame state. Is what you do.

[0007]

According to the first aspect of the present invention,
Cement, wood chips and average particle size 0.5 to 5.0 mm, S
A wood chip cement plate made of vermiculite having an iO ₂ content of 32 to 40% and a loss on ignition of 9 to 16% by weight, wherein the content of the vermiculite is 0.5 to 10% by weight of the obtained wood chip cement plate. It is characterized by having.

The invention according to claim 2 provides cement, wood chips and an average particle size of 20 to 600 μm, and a specific gravity of 0.2 to 0.
5. A wood chip cement board made of inorganic hollow particles having a hollow ratio of 50 to 90%, wherein the content of the inorganic hollow particles is 10 to 60% by volume of the obtained wood chip cement board. Things.

A third aspect of the present invention is a wood chip cement board 1.
And a wood chip cement board 2 in which the wood chip cement board 2 is laminated, the wood chip cement board 1 is made of cement, wood chip and vermiculite, and the wood chip cement board 1 obtained from the vermiculite content is 0.5 to 10%. And the wood chip cement board 2 is made of cement and wood chips, is stacked on the back surface of the wood chip cement board 1 at a bulk specific gravity of 1.0 to 1.8 and has a thickness of 0.5 to 10 mm, and contains the wood chip. The amount is 3 to 15% by weight of the obtained wood chip cement board 2.

[0010] In the first aspect of the present invention, as the cement used for the wood chip cement board, a cement mainly composed of Portland cement such as ordinary Portland cement or early-strength Portland cement can be used.

When a heating step such as a hot press is used in the molding step, the curing time can be shortened, so that a thermosetting component can be added to Portland cement.

As the thermosetting component, for example, a component selected from alumina cement, anhydrous gypsum and gypsum hemihydrate can be used as a main component alone or in a mixture of two or more. That is, ettringite (3CaO.Al ₂ O _3.
3CaSO ₄ .32H ₂ O) is formed to harden the cement.

The cement may include a filler such as silica sand, fly ash, mica, diatomite, silica fume, blast furnace slag, etc., and, if necessary, pearlite, shirasu balloon, fly ash balloon instead of part of the cement. ,
Taiheiyo Cement's trade name “E-Spheres”, inorganic lightweight aggregates such as glass balloons, and organic lightweight aggregates such as styrene beads and polyethylene beads may be used.

In the invention according to the first aspect, the wood chip used for the wood chip cement board is not particularly limited, but a wood chip obtained by subdividing a wood chip made from new wood, construction waste wood, or the like is preferable. Can be used as tree species, for example, cedar, cypress, pine, toga, straw, oak, birch, beech, oak, lauan, hiba, chestnut, zelkova, vertebra,
Willow, bamboo and the like.

In the first aspect of the present invention, the vermiculite used for the wood chip cement board expands at a high temperature to suppress the shrinkage behavior of the wood chip cement board.
This vermiculite has an average particle size of 0.5 to
It is limited to those having 5.0 mm, a SiO ₂ content of 32 to 40%, and a loss on ignition of 9 to 16% by weight.

The average particle size of the vermiculite is 0.5
If the average particle diameter is larger than 5.0 mm, only the periphery of vermiculite expands locally and becomes explosive if the average particle diameter is larger than 5.0 mm. However, it has the opposite effect of damaging the wood chip cement board. Also,
If the SiO ₂ content of the vermiculite is less than 32%, the hydrogen bonding rate of the water present in the vermiculite becomes too small and the vermiculite expands from a low temperature. If the SiO ₂ content exceeds 40%, the expansion start temperature becomes high. Too much.
Therefore, in order to cause the vermiculite to expand in parallel with the burning of the wood chips and the desorption of the cement-bound water, it is necessary to use SiO ₂
The content is limited to 32 to 40%. Further, if the loss on ignition of vermiculite is less than 9% by weight, the expansion coefficient is insufficient, and if the loss on ignition exceeds 16% by weight, the material is excessively expanded and the cured cement is destroyed. Vermiculite that satisfies these conditions includes vermiculite from Australia and vermiculite from South Africa.

In the first aspect of the present invention, the content of vermiculite is 0.5 to 0.5% in the obtained wood chip cement board.
Limited to 10% by weight. When the vermiculite is 0.1%.
When the amount is less than 5% by weight, the expansion rate is insufficient, and when the amount of vermiculite is more than 10% by weight, the vermiculite expands too much and breaks the hardened cement.

According to the first aspect of the present invention, the mixing ratio of the cement composition, the wood chips and the water in the cement board of the wood chips is 5 to 40 parts by weight of the wood chips and 30 to 100 parts by weight with respect to 100 parts by weight of the cement composition. It is preferably in parts by weight.

When the amount of the wood piece is less than 5 parts by weight, the reinforcing effect cannot be obtained, the strength becomes insufficient, the specific gravity increases, and the weight of the wood chip cement board may increase. On the other hand, if the amount of the wood chips exceeds 40 parts by weight, the amount of the binder due to the cement hardening component becomes too small, and conversely, the strength may be reduced.

If the amount of water is less than 30 parts by weight, the hydration reaction of the cement becomes insufficient and the strength is reduced. On the other hand, if the amount of water exceeds 100 parts by weight, water not used for the hydration reaction remains in the hardened cement body as voids, and the formed wood chip cement board is inhomogeneous and loses strength.

According to the first aspect of the present invention, the expansion of vermiculite acts on the shrinkage behavior due to the burning of the wood chips and the desorption of the bound water of the cement hydrate during the flame, and the cracks of the wood chip cement plate are generated. Therefore, it is difficult to transmit flame and heat to the back surface, and a wood chip cement board excellent in fire resistance can be obtained.

In the second aspect of the present invention, as the cement used for the wood chip cement board, a cement mainly composed of Portland cement such as ordinary Portland cement and early-strength Portland cement can be used.

When a heating step such as a hot press is used in the molding step, the curing time can be shortened, so that a thermosetting component can be added to Portland cement.

As the thermosetting component, for example, a component selected from alumina cement, anhydrous gypsum and gypsum hemihydrate can be used as a main component alone or in a mixture of two or more. That is, ettringite (3CaO.Al ₂ O _3.
3CaSO ₄ .32H ₂ O) is formed to harden the cement.

The cement may include a filler such as silica sand, fly ash, mica, diatomite, silica fume, blast furnace slag, etc., and, if necessary, an inorganic lightweight material such as pearlite or shirasu balloon. It may be replaced with an aggregate or an organic lightweight aggregate such as styrene beads or polyethylene beads.

In the invention according to claim 2, the wood chip used for the wood cement board is not particularly limited, but a wood chip obtained by subdividing a wood chip made from new wood, waste construction wood, or the like is preferable. Can be used as tree species, for example, cedar, cypress, pine, toga, straw, oak, birch, beech, oak, lauan, hiba, chestnut, zelkova, vertebra,
Willow, bamboo and the like.

According to the second aspect of the present invention, the inorganic hollow particles used in the wood chip cement board have an average particle diameter of 20%.
~ 600μm, bulk specific gravity 0.2 ~ 0.5, hollow ratio 5
It is limited to what is 0-90%.

When the average particle diameter of the inorganic hollow particles is less than 20 μm, the heat insulating property and expansion force of the hollow air layer are small,
Sufficient effects cannot be achieved and the average particle size is 600 μm
If it is larger, the air layer is localized, and the heat insulation of the whole wood chip cement board becomes uneven, which is an adverse effect. Also, when the bulk specific gravity of the inorganic hollow particles is smaller than 0.2, the hollow particles are easily crushed in the molding step, and when the bulk specific gravity exceeds 0.5,
The heat insulation is reduced. Furthermore, the hollow ratio of the inorganic hollow particles is 5
When it is less than 0%, the heat insulating property is insufficient, and when it exceeds 90%, the hollow particles are easily broken in a molding step or the like, and it is difficult to uniformly disperse the air layer. Examples of the inorganic hollow particles satisfying such conditions include fly ash balloons, hollow glass beads, and trade name “E-Spheres” manufactured by Taiheiyo Cement Corporation.

In the second aspect of the present invention, the content of the inorganic hollow particles is limited to 10 to 60% by volume of the obtained wood chip cement board. When the amount of the inorganic hollow particles is less than 10% by volume, the heat insulating effect is too low, and when the amount of the inorganic hollow particles exceeds 60% by volume, the bending strength of the wood chip cement board is not sufficiently exhibited.

In the invention according to claim 2, the mixing ratio of the cement composition, the wood chips and the water of the wood chip cement board is such that the cement composition is 100 parts by weight, the wood chips are 5 to 40 parts by weight, and the water is 30 to 100 parts by weight. It is preferably in parts by weight.

If the amount of the wood piece is less than 5 parts by weight, the reinforcing effect cannot be obtained, the strength becomes insufficient, the specific gravity increases, and the weight of the wood cement board may increase. On the other hand, if the amount of the wood chips exceeds 40 parts by weight, the amount of the binder due to the cement hardening component becomes too small, and conversely, the strength may be reduced.

If the amount of water is less than 30 parts by weight, the hydration reaction of the cement becomes insufficient and the strength is reduced. On the other hand, if the amount of water exceeds 100 parts by weight, water not used for the hydration reaction remains in the hardened cement body as voids, and the formed wood chip cement board is inhomogeneous and loses strength.

According to the second aspect of the present invention, since the air layer of the inorganic hollow particles is dispersed in the wood chip cement board, the speed of transferring heat to the opposite side when the flame is applied from one side is greatly reduced. In addition, the air layer of the inorganic hollow particles resists the shrinkage behavior due to the burning of the wood chips and the desorption of the bound water from the cement hydrate, and the cracks on the wood chip cement board are suppressed. It is possible to obtain a wood chip cement board which is less likely to transmit flame and heat to the fire and has excellent fire resistance.

In the third aspect of the invention, as the cement used for the wood chip cement plates 1 and 2, a cement mainly containing Portland cement such as ordinary Portland cement or early-strength Portland cement can be used.

When a heating step such as a hot press is used in the molding step, the curing time can be shortened, so that a thermosetting component can be added to Portland cement.

As the thermosetting component, for example, a component selected from alumina cement, anhydrous gypsum and hemihydrate gypsum can be used as a main component alone or in a mixture of two or more. That is, ettringite (3CaO.Al ₂ O _3.
3CaSO ₄ .32H ₂ O) is formed to harden the cement.

In the cement, instead of part of the cement, filler such as silica sand, fly ash, mica, silica sand, silica fume, blast furnace slag, etc., and if necessary, pearlite, shirasu balloon, fly ash balloon ,
Taiheiyo Cement's trade name “E-Spheres”, inorganic lightweight aggregates such as glass balloons, and organic lightweight aggregates such as styrene beads and polyethylene beads may be used.

In the invention according to claim 3, the wood chips used for the wood chip cement plates 1 and 2 are not particularly limited, but wood chips made from new wood, construction waste wood and the like are subdivided. Wood chips can be suitably used, and as tree species, for example, cedar, cypress, pine, toga, straw, oak, nara, birch, beech, oak, lauan, hiba, chestnut, keyaki,
Shii, willow, bamboo and the like.

According to the third aspect of the present invention, the vermiculite used for the wood chip cement board 1 expands at a high temperature to suppress the shrinkage behavior of the wood chip cement board 1, and the vermiculite has an average particle size of 0. 0.5-3.
0 mm, SiO ₂ content of 40-50%, ignition loss 1
It is preferably from 0 to 15% by weight.

The average particle size of the vermiculite is 0.5
If the average particle diameter is larger than 3.0 mm, only the periphery of the vermiculite locally expands too much if the average particle diameter is larger than 3.0 mm. Explosion and damage to the wood chip cement board, which can be counterproductive. In addition, the vermiculite SiO
_{2 If the} content is less than 40%, the hydrogen bonding rate of water present in the vermiculite is too low, and the water expands from a low temperature. If the SiO ₂ content exceeds 50%, the expansion start temperature becomes too high. Therefore, in order to cause the vermiculite to expand in parallel with the burning of the wood chips and the desorption of the cement-bound water, the SiO ₂ content is preferably 40 to 50%. Furthermore, the loss on ignition of vermiculite is 10% by weight.
If less, the expansion rate is insufficient and the ignition loss is 15% by weight.
If it exceeds, there is a concern that it will expand too much and destroy the hardened cement. Vermiculite that satisfies these conditions includes vermiculite from Australia and vermiculite from South Africa.

According to the third aspect of the present invention, the content of vermiculite is 0.5
To 10% by weight. If the amount of vermiculite is less than 0.5% by weight, the coefficient of expansion is insufficient.

In the invention according to claim 3, the mixing ratio of the cement composition, the wood chips and the water of the wood chip cement board 1 is as follows:
5 to 40 wood chips per 100 parts by weight of the cement composition
It is preferred that the parts by weight and water are 30 to 100 parts by weight.

When the amount of the wood chips is less than 5 parts by weight, the reinforcing effect cannot be obtained, the strength becomes insufficient, the specific gravity increases, and the weight of the wood chip cement plate may increase. On the other hand, if the amount of the wood chips exceeds 40 parts by weight, the amount of the binder due to the cement hardening component becomes too small, and conversely, the strength may be reduced.

When the amount of the water is less than 30 parts by weight, the hydration reaction of the cement becomes insufficient and the strength is reduced. On the other hand, if the amount of water exceeds 100 parts by weight, water not used for the hydration reaction remains in the hardened cement body as voids, and the formed wood chip cement board is inhomogeneous and loses strength.

According to the third aspect of the present invention, the amount of the wood chip cement board 2 is 3 to 1 of the obtained wood chip cement board 2.
Limited to 5% by weight. The wood chip cement board 2 needs to be dense and have high strength in order to reinforce the wood chip cement board 1 which becomes brittle due to wood chip combustion and vermiculite expansion at the time of flame. Therefore, when the wood chip amount is less than 3% by weight. In addition, the effect of reinforcing the wood pieces is insufficient, and the strength is reduced. Also,
If the content exceeds 15% by weight, the strength at the time of normal operation will be exhibited, but the strength will rapidly decrease due to the burning of wood chips during the flame.

According to the third aspect of the present invention, the bulk specific gravity of the wood chip cement board 2 is limited to 1.0 to 1.8. If the bulk specific gravity of the wood chip cement board 2 is less than 1.0, the strength will be low even if the amount of wood chips is appropriate, and obtaining a wood chip cement board having a bulk specific gravity exceeding 1.8 requires the above wood chip amount. It is difficult within the range.

In the third aspect of the present invention, the thickness of the wood cement board 2 is limited to 0.5 to 10 mm. If the thickness of the wood chip cement plate 2 is less than 0.5 mm, no reinforcing effect can be expected, and if the thickness exceeds 10 mm, the wood chip cement laminate becomes too heavy.

In the third aspect of the present invention, the mixing ratio of the cement composition and water in the wood chip cement board 2 is preferably 30 to 100 parts by weight with respect to 100 parts by weight of the cement composition.

If the amount of water is less than 30 parts by weight, the hydration reaction of the cement becomes insufficient and the strength is reduced. On the other hand, if the amount of water exceeds 100 parts by weight, water not used for the hydration reaction remains in the hardened cement body as voids, and the molded wood chip cement board 2 is inhomogeneous and loses its strength.

According to the third aspect of the present invention, the wood chip cement board 1 forming the wood chip cement laminate has vermiculite added thereto, so that the wood chips can be burned or the cement hydrate-bound water can be added during the flame. Vermiculite acts on the shrinkage behavior due to desorption and suppresses the generation of cracks. For this reason, it is difficult to transmit flame and heat to the wood chip cement board 2 side, and the fire resistance is excellent. Then, the wood chip cement board 1 in which the vermiculite expands becomes fragile and the strength gradually decreases. At this time, since the relatively dense wood chip cement board 2 reinforces the wood chip cement board 1, the flame The strength as a laminate can be maintained even during the process, and the fire resistance performance for a longer time can be exhibited.

[0051]

Examples (Examples 1-1 to 1-3 and Comparative Example 1-1)
１−1-5) Hereinafter, Example 1 of a wood chip cement board of the present invention.
1-1 to 1-3 and Comparative Examples 1-1 to 1-5 will be described.

The examples and comparative examples of these wood chip cement boards were prepared by mixing the compositions shown in Table 1 below with the formulations shown in Table 1.

[0053]

[Table 1]

The compositions adjusted in accordance with these formulations were mixed with a Henschel mixer, and the resulting mixture was sprayed and deposited on a metal mold, compressed, cured and cured to a thickness of 12 m.
m wood chip cement board was obtained.

Examples 1-1 to 1-1 of these wood chip cement boards
For 1-3 and Comparative Examples 1-1 to 1-5, the obtained wood chip cement board was cut into 900 mm × 900 mm, and each was heated by a fire resistance test method in accordance with JIS A 1304. The back surface temperature of the wood chip cement board after the heating time of 30 minutes and the state of cracks generated in the wood chip cement board were visually observed, and evaluated according to the following criteria.

：: No penetrating crack ×: Crack penetrating These results are shown in Table 2.

[0057]

[Table 2]

From Table 2, it can be seen that Examples 1-1 to 1 of the wood chip cement board were used.
1-3 has a low temperature on the back surface, no cracks are observed, and is excellent in fire resistance. Comparative Examples 1-1 to 1-5 are:
The temperature of the back side is high, cracks occur, and the fire resistance is poor. (Examples 2-1 to 2-2 and Comparative Examples 2-1 to 2-3)
Hereinafter, Examples 2-1 to 2-2 of the wood chip cement board of the present invention
And Comparative Examples 2-1 to 2-3 will be described.

In these examples and comparative examples of the wood chip cement boards, the compositions shown in Table 3 below were prepared with the formulations shown in Table 3.

[0060]

[Table 3]

The compositions adjusted in accordance with these formulations were mixed with a Henschel mixer, and the resulting mixture was spread and deposited on a metal mold, compressed, cured and cured to a thickness of 12 m.
m wood chip cement board was obtained.

A fly ash balloon (manufactured by Blue Circle Ash) was used as the inorganic hollow particles.

Examples 2-1 to 2 of these wood chip cement boards
For 2-2 and Comparative Examples 2-1 to 2-3, each test of fire resistance and bending strength was performed.

Regarding the fire resistance performance, the obtained wood chip cement board was cut into 900 mm × 900 mm and JIS A
Heating was performed by a fire resistance test method in accordance with 1304, and the temperature of the back surface of the wood chip cement board and the state of cracks generated in the wood chip cement board after a heating time of 30 minutes were visually observed and evaluated according to the following criteria.

：: No penetrating crack ×: Penetrating crack The bending strength of the obtained wood chip cement board was 50 m.
It was cut to mx 150 mm and performed according to JIS A 1408.

Table 4 shows the results.

[0067]

[Table 4]

From Table 4, it can be seen that Examples 2-1 to 2 of the wood chip cement board were used.
2-2 has a low back surface temperature, no cracks are observed, and is excellent in fire resistance.
The temperature of the back side is high, cracks occur, and the fire resistance is poor. Comparative Example 2-2 is inferior in bending strength. (Examples 3-1 to 3-4 and Comparative Examples 3-1 to 3-4)
Hereinafter, Examples 3-1 to 3 of the wood chip cement laminate of the present invention.
-4 and Comparative Examples 3-1 to 3-4 of the wood chip cement laminate and the wood chip cement board will be described.

The examples of the wood chip cement laminate and the comparative examples of the wood chip cement laminate and the wood chip cement board were prepared by mixing the compositions shown in Table 5 below with the formulations shown in Table 5.

[0070]

[Table 5]

The compositions thus prepared were mixed with a Henschel mixer.
Was spread and deposited on a metal mold, and then the resulting mixture of wood chip cement board 2 was sprayed and deposited thereon, compressed, cured and cured to obtain a 12 mm thick wood chip cement laminate. . The mixture of the wood chip cement board 1 was sprayed and deposited on a metal mold, compressed, cured and cured to obtain a 12 mm thick wood chip cement board 1.

Example 3 of these wood chip cement laminates
For Comparative Examples 3-1 to 3-4 of 1-3 to 1-4 and wood chip cement laminate and wood chip cement board, 900 mm × 900
mm, and each was heated by a fire resistance test method in accordance with JIS A 1304. The back surface temperature of the wood chip cement laminate at the time of the heating time of 45 minutes and the state of cracks generated in the wood chip cement laminate were visually observed and evaluated according to the following criteria.

：: No penetrating cracks Δ: No penetrating but many fine cracks X: Penetrating cracks The results are shown in Table 6.

[0074]

[Table 6]

From Table 6, Example 3 of the wood cement laminate was used.
1-3-4 have a low back surface temperature, no cracks are observed, and are excellent in fire resistance, but Comparative Examples 3-1-3-3 of the wood chip cement laminate have a high back surface temperature. In addition, cracks and fine cracks occur, resulting in poor fire resistance. Also, in Comparative Example 3-4 of the wood chip cement board, the temperature of the back surface is high, cracks and fine cracks are generated, and the fire resistance is poor.

[0076]

As described above, according to the first aspect of the present invention, expansion of vermiculite acts on shrinkage behavior due to burning of wood chips and desorption of bound water of cement hydrate during flame, Since the generation of cracks in the cement board is suppressed, it is difficult to transmit flame and heat to the back surface, and a wood chip cement board excellent in fire resistance can be obtained.

According to the second aspect of the present invention, since the air layer of the inorganic hollow particles is dispersed in the wood chip cement plate, the speed at which heat is transmitted to the opposite side during flame from one side is greatly increased. In addition, the expansion of the air layer of the inorganic hollow particles resists the shrinkage behavior due to the burning of the wood chips and the desorption of the bound water of the cement hydrate, and suppresses the generation of cracks in the wood chip cement board. In addition, it is possible to obtain a wood chip cement board which is less likely to transmit flame and heat to the back surface and has excellent fire resistance.

Further, according to the third aspect of the present invention, the vermiculite acts on the shrinkage behavior due to the burning of the wood chips and the detachment of the cement hydrate-bound water when the wood chip cement plate 1 is ignited, and cracks are generated. Suppress. For this reason, it is difficult to transmit flame and heat to the wood chip cement board 2 side, and the fire resistance is excellent. Then, the wood chip cement board 1 in which the vermiculite expands becomes fragile and the strength gradually decreases. At this time, since the relatively dense wood chip cement board 2 reinforces the wood chip cement board 1, the flame The strength as a laminate can be maintained even during the process, and the fire resistance performance for a longer time can be exhibited.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) E04B 1/94 E04B 1/94 V E04C 2/04 E04C 2/04 F E // (C04B 28/02 (C04B 28 / 02 14:06 14:06 18:26 18:26 14:20) 14:20) Z 111: 28 111: 28 F term (reference) 2E001 DE01 FA04 GA12 GA42 HA01 HC01 JA01 JA02 JA13 JC01 2E162 CA06 FA01 FA02 FA06 FC03 4F100 AA01A AA01H AA20A AA20H AC10A AC10H AE01A AE01B AJ02A AJ02B AJ02H BA02 CA23A CA23B GB07 JA13A JA13B JA13H JJ07 JK01 JK14 YY00A YY00B YY00H 4G012 PA04 PA08 PA27 PA34

Claims (3)

[Claims] Cement, wood chips and average particle size of 0.5 to 1.
5.0 mm, SiO ₂ content of 32 to 40%, loss on ignition 9
A wood chip cement board made of vermiculite having a content of up to 16% by weight, wherein the content of the vermiculite is 0.5 to 10% by weight of the obtained wood chip cement board. 2. Cement, wood chips and average particle size of 20 to 6
00 μm, bulk specific gravity 0.2-0.5, hollow ratio 50-50
A wood chip cement board comprising 0% inorganic hollow particles, wherein the content of the inorganic hollow particles is 10 to 60% by volume of the obtained wood chip cement board. 3. A wood chip cement laminate in which a wood chip cement board 1 and a wood chip cement board 2 are stacked, wherein said wood chip cement board 1 is made of cement, wood chip and vermiculite, and said wood chip having a vermiculite content is obtained. 0.5 to 10% by weight of the cement board 1, and the wood chip cement board 2 is made of cement and wood chips, and has a bulk specific gravity of 1.0 to 1.8 and a 0.5
A wood chip cement laminated board characterized in that the wood chip content is 3 to 15% by weight of the obtained wood chip cement board 2 and the content of the wood chip is 2 to 10 mm.