JP2001269924A - Woody cement board and its manufacturing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a woody cement board capable of preventing any warp or crack and excellent in dimensional stability. SOLUTION: The method of manufacturing a woody cement board comprises sequential mixing steps S1 to S4 of materials by using a Henschel mixer: step 1 wherein a mixture A is obtained by mixing a woody cement material of 100 pts.wt., a woody material of 5 to 30 pts.wt., an aggregate of 10 to 70 pts.wt., and a fiber of 0.5 to 10 pts.wt under condition of 0.04 to 0.09 kW/kg for a specified time; step 2 wherein a mixture B is obtained by adding a water of 15 to 60 pts.wt. while stirring the mixture A; step 3 wherein a mixture C is obtained by mixing the mixture B under condition of 0.20 to 0.35 kW/kg for a specified time; step 4 wherein a mixture D is obtained by mixing the mixture C under condition of 0.06 to 0.11 kW/kg for a specified time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, wood cement boards have been used mainly for the outer walls of buildings because of their excellent fire resistance and water resistance. This wood cement board is, for example, a cement material mainly composed of Portland cement, a wood material,
Aggregate, other compounding materials, and water are mixed, and then the mixture is supplied to a molding die, heated to form a predetermined shape by heating, and then cured (Japanese Patent Application Laid-Open No. Sho 56). No. -140059 and Japanese Patent Publication No. 5-13098
Reference).

[0003]

However, when the above-mentioned wood cement board is used for an outer wall of a building, it has been pointed out that warpage and cracking occur and dimensional stability is lacking.

[0004] One of the causes is that the cement product and the wood material, aggregate, and other compounding materials are not uniformly mixed at the time of production, so that the molded product does not have a uniform composition distribution. It is presumed that the denseness is insufficient, and as a result, the wood cement board expands unevenly due to water absorption or the like.

The present invention has been made in view of the above problems, and is intended to prevent the occurrence of warpage and cracking, to produce a wood cement board excellent in dimensional stability and excellent in impact resistance. It provides a method.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a wood cement board obtained by mixing a cement material, a wood material, an aggregate, a fiber, and water, and forming a mixture thereof to obtain a wood cement board. In the production method, the mixing step may include the steps of: 100 parts by weight of cement material, 10 to 70 parts by weight of aggregate,
Step S1 of mixing 5 to 10 parts by weight and 5 to 30 parts by weight of the wood material with a Henschel mixer at 0.04 to 0.09 kW / kg for a certain period of time to obtain a mixture A, and stirring the mixture A Adding 15 to 60 parts by weight of water while mixing to obtain a mixture B;
Step S3 of obtaining a mixture C by mixing for 5 hours under the condition of 5 kW / kg, and mixing the mixture C with 0.06 to 0.11 kW / kg.
Mixing for a certain period of time under the following conditions to obtain a mixture D;
And the steps S1 to S4 are performed in this order.

According to the present invention, it is possible to prevent agglomerates which are considered to be generated by the fibrillation of fibers and the increase in powder pressure due to convection after the addition of water by changing the input energy during the mixing process. And the blended materials can be mixed uniformly.

As a result, it is possible to produce a wood cement board which prevents warpage and cracks, has excellent dimensional stability, and has excellent impact resistance because a dense cured product is obtained.

Here, the Henschel mixer is, as shown in FIG. 1, a stirrer comprising a cylindrical container and a rotary shaft having stirring blades installed at the center of the container.

KW is the power at the time of driving the mixer, k
g is the mass of the raw material to be processed.

In the present invention, the processing conditions in step S1 are limited to 0.04 to 0.09 kW / kg. When the ratio deviates from the limited range, fibrillation and uniform mixing of fibers are not performed, and a uniform composition distribution of each material cannot be obtained.

In step S2, water is gradually added to mixture A. If the whole amount of water is added to the mixture A at one time, or if the mixture A is mixed into the water, non-uniform aggregates between the materials are generated, and the subsequent processing becomes difficult.

The processing conditions in step S3 are 0.20 to 0.20.
Limited to 0.35 kW / kg. When the amount is less than the limited range, a granulating action by water works, a hard aggregate is generated in the mixture C, and the subsequent treatment becomes difficult. On the other hand, when the amount is more than the limited range, convection occurs in the mixer, the powder pressure increases, and a hard agglomerate is generated in the mixture C, which makes the subsequent processing difficult.

The processing conditions in step S4 are 0.06 to
Limited to 0.11 kW / kg. If the amount is less than the limited range, not only does water not sufficiently diffuse, but also a part of the material stagnates at the lower portion of the mixer, and the mixture C becomes uneven.
On the other hand, if it is more than the limited range, the powder pressure becomes too large, and a granulating action occurs, which causes the formation of hard aggregates. These deterioration of raw material dispersibility is that the formed wood cement board does not have a uniform composition distribution and the compactness is insufficient, and as a result,
The strength may be partially reduced, or may expand unevenly due to water absorption or the like, causing warpage or bending.

In the present invention, as the cement material,
Portland cement, such as ordinary Portland cement and early-strength Portland cement, can be used. It is preferable to add a thermosetting component to Portland cement because the hardening time can be shortened if a hot press is easily used for the manufacture of the wood cement board.

As the thermosetting component, for example, a raw material selected from alumina cement, anhydrous gypsum and gypsum hemihydrate can be used alone or in combination of two or more.

From portland cement and these thermosetting components, ettringite (3CaO.Al ₂ O ₃ .3Ca)
SO ₄ .32H ₂ O) is produced and the cement is hardened.

The mixing ratio of Portland cement to the thermosetting component in the cement material is 1: 1:
9-4: 1 is preferred. Outside this range, if the content of the thermosetting component in the cement material 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 Insufficient strength to remove the mold is not obtained, conversely, the content of the thermosetting component is too large, and the content of Portland cement is too low, the raw material cost may increase , Not enough working time.

In the present invention, as the woody material, wood chips or wood flour obtained by subdividing wood chips made from new wood, construction waste wood, or the like can be used.

The size of the woody material is selected according to the needs such as the application and strength, but preferably has an average particle diameter of 2 mm or less, and is a sawdust made of a passing amount classified through a sieve having an opening of 1.00 mm. Can be suitably used, and the mesh size is 0.
Those consisting of a 50 mm sieve pass are more preferred. If the average particle size is larger than this, it is difficult to mix the woody material uniformly.

The types of wood include, for example, cedar, cypress,
Pine, toga, straw, oak, birch, beech, oak, lauan, lark, chestnut, zelkova, shii, willow, bamboo, etc. can be used.

Known methods can be used as a method for preparing the woody material. Examples of the method include pressing, pressing with a rotating roll, cutting with a slitter or a cutting machine, and the like.

The wood material used is a cement material 10
It is limited to 5 to 30 parts by weight with respect to 0 parts by weight. If the wood material is less than 5 parts by weight, the amount of free water increases at the time of mixing, small lumps are formed and the water is not uniformly dispersed, the composition of the formed wood cement board becomes non-uniform, and the strength may be insufficient. is there. On the other hand, when the amount exceeds 30 parts by weight, the amount of the cement material serving as a binder is relatively reduced, so that the strength of the formed wood cement board is reduced and the fire prevention performance is deteriorated.

In the present invention, the aggregate contributes not only to the purpose as a filler and a filler, but also to the improvement of the dispersibility of fibers and wood materials mixed at the same time.

The aggregate preferably has an average particle size of 400 μm or less, and includes silica sand, fly ash, mica,
Silica earth, silica fume, blast furnace slag and the like are used, and silica sand of 100 μm or less is particularly preferably used.
By mixing these fine aggregates, the voids formed in the process of forming the mixture are filled to form a dense cured product, and the strength and dimensional stability are improved. Average particle size 40
If it is larger than 0 μm, it is too large to fill voids in the cured product, and the cured product is not sufficiently dense.

The aggregate used is limited to 10 to 70 parts by weight based on 100 parts by weight of the cement material. Aggregate 1
If the amount is less than 0 parts by weight, the voids in the cured product will not be sufficiently filled, and the dispersibility of each material in the mixture will be poor, and the strength will be reduced. On the other hand, when the amount exceeds 70 parts by weight, the cement material in the mixture becomes relatively small, which causes a decrease in strength.

In the present invention, the fiber has a fiber diameter of 5
４０40 μm and a fiber length of 2-20 mm can be suitably used. If the fiber diameter and fiber length are smaller than these ranges, a sufficient reinforcing effect cannot be obtained, resulting in insufficient strength. On the other hand, if it exceeds this range, it is necessary to mix a large amount of fibers in order to obtain a sufficient reinforcing effect, causing problems such as aggregation of the fibers during mixing.

The type of the fiber is not particularly limited.
Organic fibers or inorganic fibers such as vinylon, acrylic, polypropylene, rayon, and glass can be used. As such a fiber, Kuraray's trade name "RMH18
2, RKW182 "(vinylon), Toyobo's product name" SKS T901 "(acrylic), Mitsubishi Rayon's product name" Taframe "(rayon), Showa Denko's product name" Musky "(polypropylene) "ACS series" (glass) manufactured by NEC Corporation and the like are commercially available.

The fiber used is limited to 0.5 to 10 parts by weight based on 100 parts by weight of the cement material. When the amount of the fiber is less than 0.5 parts by weight, a sufficient reinforcing effect cannot be obtained, and the strength is reduced. On the other hand, if the amount exceeds 10 parts by weight, it becomes difficult to uniformly mix the fibrous materials, and the fibers are agglomerated, causing a reduction in strength.

In the present invention, the water used is used for the cement hardening reaction, and is limited to 15 to 60 parts by weight based on 100 parts by weight of the cement material. If the amount is more than 60 parts by weight, uneven agglomeration occurs in the mixture. If the amount is less than 15 parts by weight, the hydration reaction of the cement becomes insufficient and the strength is reduced.

In the present invention, the wood cement board can be formed by spraying and dropping the final mixture on a mold. In this case, a hot press molding process such as hot pressing is preferably applied since a high-strength wood cement board can be obtained in a shorter time.

[0032]

EXAMPLES Examples 1 to 3 of the wood cement board of the present invention will now be described.
6 and Comparative Examples 1 to 3 will be described.

In Examples 1 to 6 and Comparative Examples 1 to 3 of these wood chip cement boards, the compositions shown in Table 1 below were prepared with the formulations shown in Table 1.

[0034]

[Table 1]

As cement materials, 83.8 parts by weight of early strength Portland cement (manufactured by Chichibu Onoda), 7.9 parts by weight of alumina cement (manufactured by Denka No. 2 Denki Kagaku), calcined gypsum (manufactured by Adra Industries) ) 4.7 parts by weight, 3.2 parts by weight of slaked lime (Komagata Lime Industry Co., Ltd.) and 0.3 parts by weight of calcium stearate (Sakai Chemical Co., Ltd.) were used.

As the woody material, a wood chip of hinoki was cut with a ring-type hammer mill of Pearlman Co., Ltd., and then finely pulverized with a ball mill.
m and classified using a sieve of m.

As the aggregate, silica sand (“No. 8 silica sand” manufactured by Rokuro Mining Co., Ltd.) and fly ash fine powder (“Super Flow” manufactured by Taiheiyo Cement Co., Ltd.) were used.

As the fiber, acrylic (“SKS T9”)
01, cut length 6 mm ", manufactured by Toyobo Co., Ltd.).

The Henschel mixer used was "FM150T / J" (manufactured by Mitsui Mining Co., Ltd.) in Examples 1-4 and Comparative Example 1, and "FM500T / J" (Mitsui Mining Co., Ltd.) in Examples 5-6 and Comparative Examples 2-3. (Mitsui Mining Co., Ltd.).

In Examples 1 to 4 and Comparative Example 1,
Step S1 was performed at a linear velocity of 10 m / s for 30 seconds, step S2 was performed at a linear velocity of 10 m / s for 60 seconds, step S3 was performed at a linear velocity of 20 m / s for 30 seconds, and step S4 was performed at a linear velocity of 6 m / s for 30 seconds. The composition was mixed.

In the fifth embodiment, step S3 is performed at a linear velocity of 2
The mixing was carried out under the same conditions as in Example 1 except that the reaction was performed at 0 m / s for 60 seconds.

In the sixth embodiment, step S3 is performed at a linear velocity of 1
Mixing was performed under the same conditions as in Example 1 except that the reaction was performed at 5 m / s for 30 seconds.

In Comparative Example 2, step S1 was performed at a linear velocity of 2
Mixing was performed under the same conditions as in Example 5 except that the reaction was performed at 5 m / s for 60 seconds.

In Comparative Example 3, step S3 was performed at a linear velocity of 1
The mixing was carried out under the same conditions as in Example 1 except that the reaction was performed at 0 m / s for 60 seconds.

The final mixture mixed under these conditions is:
Spray and drop on metal formwork to deposit, pressure 3.9
12 at ² MPa (40 kgf / cm ² ) and 93 ° C.
After being hardened by hot pressing for a minute, the mold was removed to obtain a wood cement board having a thickness of about 15 mm.

With respect to Examples 1 to 6 and Comparative Examples 1 to 3 of the obtained wood cement board, tests were conducted on the bending strength and the change in water absorption length.

Regarding the bending strength, JIS A 140
According to No. 8, the test was performed on a test specimen of one week of age.

Regarding the change in water absorption length, the obtained wood cement board was cut into a dumbbell shape having a length of 150 mm and a width of 50 mm, dried at 60 ° C. for one day, and immersed in water.
The dimensions after immersion each day were measured with a micrometer, and the rate of change in water absorption length was calculated from the following equation.

Change in water absorption length (%) = (dimension after immersion in water—dimension after initial drying) / dimension after initial drying × 100 The results are shown in Table 2.

[0050]

[Table 2]

Table 2 shows that Examples 1 to 6 of the wood cement board were used.
Is superior in both strength and dimensional stability as compared with Comparative Examples 1 to 3.

In Examples 1 to 6, no aggregates of the material were observed on the surface, whereas in Comparative Examples 1 to 3, aggregates of the material were observed on the surface.

Therefore, in Examples 1 to 6, it is clear that the mixture was not aggregated during the mixing step and was uniformly mixed.

[0054]

As described above, according to the present invention, in the step of obtaining the material mixture of the wood cement board, the dispersibility of the raw materials is reduced because the cement material, the wood material, the aggregate, and the fibers are uniformly dispersed. It becomes favorable and a uniform and dense cured product can be obtained. Therefore, the formed wood cement board has excellent dimensional stability and strength.

[Brief description of the drawings]

FIG. 1 is a schematic view of a Henschel mixer used in the method for producing a wood cement board of the present invention.

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Claims (1)

[Claims] 1. A cement material, a wood material, an aggregate,
In a method for producing a wood cement board, in which fibers and water are mixed and a mixture thereof is formed to obtain a wood cement board, the mixing step includes: 100 parts by weight of cement material; 5 to 30 parts by weight of wood material; A step S1 of mixing 10 to 70 parts by weight of the aggregate and 0.5 to 10 parts by weight of the fiber using a Henschel mixer under a condition of 0.04 to 0.09 kW / kg for a certain period of time to obtain a mixture A; While stirring A, add 15 to 60 parts by weight of water,
Step S2 of obtaining a mixture B, Step S3 of mixing the mixture B under a condition of 0.20 to 0.35 kW / kg for a certain period of time to obtain a mixture C, and a condition of 0.06 to 0.11 kW / kg of the mixture C And a step S4 of obtaining a mixture D by mixing for a certain period of time, wherein steps S1 to S4 are performed in this order.