JP2001080946A - Wood chip cement board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cement board hardly generating a warp and a crack and excellent in dimensional stability by preparing a mixture by blending the mixture of wood chips, aggregate and fibers with the mixture of cement and aggregate and mixing the obtained mixture with water. SOLUTION: The production method of this wood chip cement board comprises a step 1 to obtain the mixture 1 by blending 5-30 pts.wt. wood chips, 5-35 pts.wt. aggregate and 0.5-10 pts.wt. fibers, a step 2 to obtain the mixture 2 by blending 100 pts.wt. cement composition and 5-35 pts.wt. aggregate, a step 3 to obtain the mixture 3 by blending the mixtures 1 and 2 and a step 4 to obtain a mixed composition by mixing the mixture 3 with 15-60 pts.wt. water. Steps 1 and 2 are carried out in parallel and subsequently step 3 and step 4 are done in this order. As the wood chips, the ones which are obtained by pulverizing wood pieces and each of which has preferably 2 mm or smaller average particle size can be used. As the aggregate, silica sand, fly ash, mica, diatomaceous earth, or the like, having 400 μm or smaller average particle size is preferably used.

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 used as a building material for an outer wall or the like.

[0002]

2. Description of the Related Art Conventionally, a wood chip cement plate used for an outer wall of a building is mainly made of Portland cement as described in, for example, JP-A-56-140059 and JP-B-5-13098. It is known that a wood chip and water are mixed with a cement composition as a component, the composition is formed into a desired plate shape by pressing, and the composition is produced by heating or the like.

[0003]

However, in the case of the conventional wood chip cement board, when used for an outer wall of a building, there is a problem that warpage and cracks are generated and dimensional stability is poor. As one of the causes, at the time of manufacturing, because the cement composition of the material and other compounding materials are not evenly mixed, the product after pressing does not have a uniform composition distribution and lacks denseness, due to water absorption It is presumed to be due to partial expansion of the wood chip cement board.

The present invention has been made in view of such a problem of the conventional wood chip cement board, and an object of the present invention is to solve the problems of the conventional wood chip cement board, and to provide the warp and crack. It is an object of the present invention to provide a wood chip cement board which is free from occurrence of swarf and has excellent dimensional stability.

[0005]

According to a first aspect of the present invention, a wood chip cement board (invention 1) is obtained by mixing a wood chip, an aggregate, a fiber, a cement composition, and water, and mixing the mixture. A wood chip cement board obtained by molding an object, the manufacturing process is 5 to 30 parts by weight of wood pieces, aggregate 5 to
Step 1 of obtaining a mixture 1 by mixing 35 parts by weight and 0.5 to 10 parts by weight of fiber, and mixing 2 by mixing 100 parts by weight of a cement composition and 5 to 35 parts by weight of aggregate Step 1, a step 3 of mixing the mixture 1 and the mixture 2 to obtain a mixture 3, and a step 4 of mixing the mixture 3 with 15 to 60 parts by weight of water to obtain a mixed composition 4. And step 2 are performed in parallel, followed by step 3 and step 4
Are produced in this order.

A wood chip cement board according to claim 2 of the present invention (invention 2) is obtained by mixing a wood chip, an aggregate, a fiber, a cement composition, and water, and molding the mixed composition. The obtained wood chip cement board, wherein the manufacturing process is a step of obtaining a mixture 1 by mixing 5 to 30 parts by weight of a wood piece, 5 to 35 parts by weight of aggregate, and 0.5 to 10 parts by weight of fiber. And mixture 1 and 8 to 30 parts by weight of water to obtain mixture 2
2, a mixture 3 of 100 parts by weight of the cement composition and 5 to 35 parts by weight of aggregate to obtain a mixture 3, and a mixture 3 of 8 to 30 parts by weight of water And Step 4 to obtain a composition 4.
It is a wood chip cement board characterized by being manufactured in this order.

Invention 1 is a method of manufacturing a wood chip cement board from a mixed composition having excellent uniform dispersibility, obtained by dispersing aggregate in advance in a cement composition and then mixing water required for a hardening reaction. The invention 2 is characterized in that the wood chip cement is produced from a mixed composition having excellent uniform dispersibility, which is obtained by mixing water required for a cement hardening reaction twice and mixing them. Features.

[0008] The present invention is a wood chip cement board obtained by a process in which the mixing order of materials is specified. That is, if all the materials are mixed at the same time, the specific gravity and the particle size of each material are greatly different, so that the dispersion is not uniform, and
If they are mixed for a long time to disperse them evenly, the strength of each material will vary greatly.For example, the material will be damaged, for example, by cutting fibers or pulverizing wood chips. There is a possibility that the properties and uniformity may be reduced, the strength may be insufficient, and warpage or bending may be caused.

Therefore, in the present invention, the mixing step
Materials that can be mixed relatively uniformly are mixed in different steps, and the resulting mixture is mixed in the next step, so that the entire material is uniform in a short time. And damage to the material is reduced.

(Material used in the present invention) As the wood piece in the present invention, a wood chip obtained by subdividing a wood chip made from new wood, waste construction wood, or the like can be used. The size is selected according to the application, strength and the like, but is preferably an average particle size of 2 mm or less, and a sawdust-like material having a sieve passing through a sieve having an opening of 1 mm can be suitably used. Those consisting of a part passing through a sieve of 0.5 mm are more preferred.
If the average particle size of the wood chips becomes larger than this, it becomes difficult to mix the wood chips uniformly.

The types of wood used include, for example,
Cedar, cypress, pine, toga, straw, oak, nara, birch, beech, oak, lauan, hiba, chestnut, zelkova, shii, willow, bamboo, and other materials are used. As a method for producing a piece of wood, a known method can be used, for example, a press,
Examples of the method include squeezing with a rotating roll, cutting with a slitter and a cutting machine, and the like.

The amount of wood chips is limited to 5 parts by weight or more and 30 parts by weight or less. If the amount is less than 5 parts by weight, the amount of free water increases at the time of mixing, small lumps are formed and cannot be uniformly dispersed, the formed wood chip cement board becomes inhomogeneous, and the strength may be insufficient. Also, if the amount of wood chips is 30
If the amount is more than the weight part, the amount of cement serving as a binder becomes small, causing problems such as a decrease in strength and a deterioration in fire prevention performance.

The aggregate in the present invention is not only intended as a filler, but also involved in improving the dispersibility of mixed fibers and wood chips. Usually, silica sand, fly ash, mica, diatomaceous earth, silica fume, blast furnace slag Are used.

The average particle size of the aggregate is preferably about 400 μm to less than 400 μm, and silica sand of 100 μm or less is particularly preferably used. By adding these fine aggregates, the voids formed during the molding process of the cement composition are filled to form a dense cured product, and the strength and dimensional stability are improved. If the average particle size is larger than 400 μm, it is too large to fill the voids of the hardened cement, and the hardened body is not sufficiently dense.

The amount of the aggregate is limited to 10 parts by weight or more and 70 parts by weight or less. If the amount is less than 10 parts by weight, the voids in the wood chip cement board of the product cannot be sufficiently filled, and the strength decreases. On the other hand, if it is more than 70 parts by weight, the dispersing performance of the mixed composition 4 is deteriorated, the uniformity of the wood chip cement board of the product is impaired, and the strength is reduced.

The fiber in the present invention has a fiber diameter of 5 μm.
Those having a length of not less than m and not more than 40 μm and a fiber length of not less than 2 mm and not more than 20 mm are suitably used. If the fiber diameter and fiber length are smaller than these ranges, sufficient reinforcing effect cannot be obtained, resulting in insufficient strength. On the other hand, if it exceeds this range, it is necessary to add a large amount to obtain a sufficient reinforcing effect, which causes problems such as aggregation of fibers.

The type of fiber is not particularly limited, but may be vinylon, acrylic, polypropylene, rayon,
Organic or inorganic fibers such as glass can be used. As such a fiber material, Kuraray's trade name “RM182,
RKW182 ”(vinylon), trade name“ S ”manufactured by Toyobo
KS T901 ”(acrylic), Mitsubishi Rayon product name“ Taframe ”(rayon), Showa Denko product name“ Musky ”(polypropylene), NEC Glass product name“ ACS series ”(glass ) Are commercially available.

The amount of the fiber is limited to 0.5 to 10 parts by weight. If less than 0.5 parts by weight,
A sufficient reinforcing effect cannot be obtained and the strength is reduced. Also, 10
When the amount is more than the weight part, it is difficult to mix the fibers uniformly, and the fibers are agglomerated, resulting in a decrease in strength.

The cement composition used in the present invention is a composition mainly composed of Portland cement such as ordinary Portland cement and early-strength Portland cement, and blended with a thermosetting component and the like. When a hot press is used for the production of a wood chip cement board, the thermosetting component is preferably used as a compounding material because the curing time of the cement can be shortened. As the thermosetting component, for example, a component selected from alumina cement, anhydrous gypsum and amniotic gypsum alone or a mixture of two or more types is used as a main component. From Portland cement and these components, ettringite (3CaO.Al ₂ O ₃ .3Ca)
SO ₄ .3H ₂ O) is produced and the cement is hardened.

The mixing ratio of Portland cement to the thermosetting component in the cement composition is preferably from 1: 9 to 4: 1 by weight. Outside this range, if the content of the thermosetting component in the cement composition is too small and the content of Portland cement is too large, the hardening reaction of the cement does not progress much during hot pressing, and the pressing die If the strength is not sufficient to release from the mold, the content of the thermosetting component is too large, and the content of Portland cement is too small, the raw material cost may increase, Work time cannot be obtained.

(Step 1 of Invention 1) Step 1 of Invention 1
Is a step of mixing 5 to 30 parts by weight of wood pieces, 5 to 35 parts by weight of aggregate, and 0.5 to 10 parts by weight of fiber to obtain a mixture 1, and step 2 is 100 parts by weight of a cement composition. And 5 to 35 parts by weight of aggregate to obtain a mixture 2. In step 3, the mixture 1 obtained in step 1 and the mixture 2 obtained in step 2 are mixed. This is the step of obtaining No. 3.

In step 1, the amounts of wood chips and fibers are as follows:
The total amount to be blended in the product, the blending amount of the aggregate to be blended in each of the steps 1 and 2 is limited to 5 parts by weight or more and 35 parts by weight or less for each step, and It is blended so that the total usage does not exceed 70 parts by weight. Whether the amount of aggregate added in each step is less than 5 parts by weight or more than 35 parts by weight, the dispersing performance of the aggregate in the mixture 2 is deteriorated, and The uniformity of the wood cement board is impaired and the strength is reduced.

The aggregate added in the step 1 contributes not only to the filling purpose but also to the improvement of the dispersibility of the fiber and the wood chips previously mixed. By adding these fine aggregates, the wood chip cement board of the product becomes a dense cured product, and the strength and dimensional stability are improved. As the aggregate used for this purpose, those having an average particle diameter of 400 μm are preferable, and silica sand, fly ash, mica, diatomaceous earth, silica fume, and blast furnace slag windows are used, and silica sand of 100 μm or less is particularly preferably used. Further, for the purpose of obtaining the strength and dense structure of the wood chip cement board of the product, as the aggregate to be blended in the step 2, for example,
Fly ash fines are particularly preferably used.

Step 4 in Invention 1 is a step of mixing the mixture 3 obtained in Step 3 with 15 to 60 parts by weight of water to obtain a mixed composition 4. In this step, water is gradually added to the mixture. That is, if the total amount of water is added to the mixed composition at once and mixed, uneven coagulation between the materials occurs,
There is a possibility that so-called lumps may be generated. When the mixed composition is added to water, lumps are also easily generated.

(Step of Invention 2) Step 1 of Invention 2
Is a step of obtaining a mixture 1 by mixing 5 to 30 parts by weight of wood pieces, 5 to 35 parts by weight of aggregate, and 0.5 to 10 parts by weight of fibers.

The amount of wood chips and the amount of fibers blended in step 1 are the total amounts blended in the wood chip cement board of the product, and the amount of aggregate is limited to 5 parts by weight or more and 35 parts by weight or less. Whether the amount of the aggregate is less than 5 parts by weight or more than 35 parts by weight, the dispersibility of the aggregate in the mixture 1 is deteriorated, and the uniformity of the wood chip cement board of the product is impaired. The strength decreases.

Step 2 comprises mixing the mixture 1 obtained in Step 1 with:
In this step, a mixture 2 is obtained by mixing 8 to 30 parts by weight of water. The water added in this step is about half of the total required amount. That is, the added water is used for the cement hardening reaction, but if the amount added in this step is 30 parts by weight or more, when the cement composition is mixed in the next step, the water will be uneven. Agglomeration is likely to occur and lumps are likely to occur, and the mixture 3 becomes non-uniform, and the compactness performance of the wood chip cement board of the product is reduced, strength may be reduced, and warpage or bending may be caused. .

Step 3 is a step of mixing mixture 2 obtained in step 2, 100 parts by weight of the cement composition, and 5 to 35 parts by weight of aggregate to obtain mixture 3. The mixture 2 obtained in the step 2 is in a wet sludge state already mixed with water, but since the amount of water is small, the mixture 2 is mixed with the cement composition and the aggregate to form a mixture 3 In the case where is obtained, there is no generation of lumps as in the case where the whole amount of water is mixed at once.

Further, the amount of aggregate to be blended in step 3 is limited to 5 parts by weight or more and 35 parts by weight or less. The amount of aggregate is 5
Even if it is less than 35 parts by weight,
The dispersibility of the aggregate in the mixture 1 becomes poor, and the uniformity of the wood chip cement board of the product is impaired and the strength is reduced.

The aggregate contributes not only to the filling purpose but also to the improvement of the dispersibility of fibers and wood chips. By adding these fine aggregates, the wood chip cement board of the product becomes a dense cured product, and the strength and dimensional stability are improved. For this purpose, as the aggregate to be blended in the step 1, for example, silica sand is preferable, and as the aggregate to be blended in the step 2, for example, fly ash fine powder is particularly suitably used.

Step 4 comprises mixing the mixture 3 obtained in step 3 with:
In this step, mixed composition 4 is obtained by mixing 8 to 30 parts by weight of water. The mixture 3 is uniformly mixed as described above, and has a small amount of incorporated water. Therefore, in this step, water necessary for the cement hardening reaction is additionally added, and the amount of water to be added is desirably 8 to 30 parts by weight. That is, 8
If the amount is less than 10 parts by weight, the cement hydration reaction becomes insufficient and the strength of the wood chip cement board becomes insufficient. If the amount exceeds 30 parts by weight, lumps are easily generated in the mixed composition 4.

The mixing method in all the steps in Inventions 1 and 2 does not need to be particularly limited, and a commercially available mixer can be used. For example, an omni mixer, a Henschel mixer, or the like can be used. The stirring condition at this time is not particularly limited as long as each composition is appropriately dispersed.

(Formation of Wood Chip Cement Board) Each of the mixed compositions 4 obtained in the inventions 1 and 2 is sprayed and dropped on a mold, pressed and formed into a wood chip cement board. At this time, a pressure and heat molding process such as a hot press is preferably applied since a high-strength cement board can be obtained in a shorter time.

(Function) As described above, the mixed composition 4 can be made into a mixed state in which the materials are uniformly dispersed by passing through the mixing step of the present invention. Means improved denseness.
Therefore, the strength is high, and the warpage and bending are small.

[0035]

Next, embodiments of the present invention will be described with reference to non-limiting examples. Table 1 shows the materials used in the production examples and comparative examples of the wood chip cement board of the present invention and the compounding amounts thereof.

[0036]

[Table 1]

(Examples 1 to 4) In each of the examples, wood chips obtained by cutting cypress wood chips with a ring-type hammer mill manufactured by Pearlman Co., Ltd., and further finely pulverizing with a ball mill, were used as the wood chips. Classify it with a sieve of opening 0.50mm,
Only that passage was used. As the cement composition, 83.8 parts by weight of early strength Portland cement (manufactured by Chichibu Onoda), 7.9 parts by weight of alumina cement (trade name “Denka No. 2”, manufactured by Denki Kagaku), calcium carbonate (manufactured by Calceed) 2.) 4.7 parts by weight, slaked lime (Komagata Lime Industry Co., Ltd.)
A premix of 2 parts by weight was used. As the fine aggregate, silica sand ("No. 8 silica sand" manufactured by Rokuro Mining Co., Ltd.) and fine fly ash powder (trade name "Super Flow", manufactured by Taiheiyo Cement Corporation) were used. Acrylic fiber (cut length 4 mm, trade name “SKS T901”, manufactured by Toyobo Co., Ltd.) was used as the fiber.

The cement composition, wood chips, aggregate, fiber and water were mixed using a Henschel mixer (Mitsui Kozan Co., Ltd.). The mixing procedure is as follows: first, mix and stir the wood chips, No. 8 silica sand and fiber material, then add the cement composition and fly ash fine powder in advance, add the cement composition mixed with a Henschel mixer, mix and stir, Finally, water was added and mixed and stirred to obtain a mixed composition.

(Examples 5 to 8) The types, total amounts and mixing methods of the blending materials were the same as in Examples 1 to 4. The mixing procedure is as follows: first, the wood chips, No. 8 silica sand and fiber material are mixed and stirred, then water is mixed, then the cement composition and fly ash fine powder are added and mixed, and water is again added to this mixture and mixed. The mixture was stirred to obtain a mixed composition.

(Comparative Example 1) Materials and compounding amounts were as shown in Table 1. The mixing method uses the same Henschel mixer as in the example, mixing fine wood chips, fine aggregate and fiber material as a mixing procedure, then mixing the cement composition, then adding the fine aggregate, and finally adding water. In addition, a mixed composition was obtained.

(Comparative Example 2) Materials, compounding amounts, and mixing method were the same as those in Comparative Example 1.
The fine aggregate and the fiber material were mixed, then water was mixed, and then the cement composition and the fine aggregate were sequentially added to obtain a mixed composition.

In all of the examples and comparative examples, the obtained mixed composition was sprayed and dropped on a metal mold, deposited and hot-pressed at a pressure of 40 kg / cm ^{2 at} a temperature of 93 ° C. for 12 minutes. After curing, a wood chip cement board having a thickness of about 15 mm was obtained.

The obtained wood chip cement plate was tested for bending strength and change in water absorption length. The flexural strength was measured on a one-week-old sample according to JIS A-1408. For the change in water absorption length, the obtained wood chip cement board was cut into a dumbbell shape with a length of 150 mm and a width of 50 mm, dried at 60 ° C. for one day, and immersed in water for one day. Was measured with a micrometer, and the rate of change in water absorption length was calculated from the following equation. Water absorption length change rate (%) = (dimension after immersion in water-dimension after initial drying) / dimension after initial drying x 100

Table 2 shows the measurement results of the physical properties of the wood chip cement boards obtained in the above Examples and Comparative Examples. From this table,
It can be seen that the wood chip cement board of the present invention is excellent in both strength and dimensional stability, but the sample of the comparative example is inferior in each performance.

[0045]

[Table 2]

[0046]

As described above, the wood chip cement board obtained in the invention 1 has a good dispersibility of the raw material mixture because the cement and the aggregate are previously uniformly dispersed in the step of obtaining the raw material mixture. Since the dense structure of the obtained wood chip cement board is uniform, strength and dimensional stability are excellent.

The wood chip cement board obtained in the invention 2 has good dispersibility of the raw material mixture because the water for promoting the hydration of the cement is divided and mixed twice in the step of obtaining the raw material mixture. Since the dense structure of the wood chip cement board is uniform, strength and dimensional stability are excellent.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court (Reference) C04B 18:14 14:38 16:06) 111: 00 (72) Inventor Yoichi Ikemoto Kamibaba, Minami-ku, Kyoto-shi 2-2 Kami-cho Town Sekisui Kagaku Co., Ltd. PA24 PA27 PA28 PA29 PA34

Claims (2)

[Claims] 1. A wood chip cement board obtained by mixing a wood chip, an aggregate, a fiber, a cement composition, and water, and molding the mixed composition, wherein the wood chip is manufactured in a wood chip cement board. Step 1 of mixing 5 to 30 parts by weight, 5 to 35 parts by weight of aggregate, and 0.5 to 10 parts by weight of fiber to obtain mixture 1, 100 parts by weight of cement composition, and 5 to 35 parts of aggregate Part 2 to obtain a mixture 2 by mixing the mixture 1 and 2 parts by weight, step 3 to obtain a mixture 3 by mixing the mixture 1 and the mixture 2 and a mixture composition of mixing the mixture 3 and 15 to 60 parts by weight of water. 4. A wood chip slab which is manufactured by performing step 4 to obtain step 4, wherein step 1 and step 2 are performed in parallel, and then step 3 and step 4 are performed in this order. 2. A wood chip cement board obtained by mixing a wood chip, an aggregate, a fiber, a cement composition, and water, and molding the mixed composition, wherein the manufacturing process is performed using a wood chip. Step 1 of mixing 5 to 30 parts by weight, 5 to 35 parts by weight of aggregate, and 0.5 to 10 parts by weight of fiber to obtain mixture 1, mixing mixture 1 with 8 to 30 parts by weight of water Mixture 2
2, a mixture 3 of 100 parts by weight of the cement composition and 5 to 35 parts by weight of aggregate to obtain a mixture 3, and a mixture 3 of 8 to 30 parts by weight of water And Step 4 to obtain a composition 4.
A wood chip cement board manufactured in this order.