JP2012171799A - Inorganic plate and method of manufacturing inorganic plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic plate excellent in wind pressure resistance and long term durability, and a method of manufacturing the same.SOLUTION: This inorganic plate is formed by extruding a raw material mixture comprising cement, a silicic acid-containing substance and an organic fiber, and it contains the cement and the silicic acid-containing substance in the range of 45/55-55/45 in mass ratio and 3-8 mass% of the organic fiber to the total solid content, and it has a specific gravity of 1.4-2.0, a dimensional change rate by moisture discharge in 10 days at 80°C of not higher than 0.1%, a dimensional change rate by moisture absorption in 7 days of not higher than 0.1%, a dimensional change rate in 7 days under a 5% carbon dioxide concentration environment of not higher than 0.1% and a bending strength of not lower than 20 N/mm. This method of manufacturing the inorganic plate comprises a process in which the raw material mixture comprising the cement, the silicic acid-containing substance and the organic fiber is manufactured, a process in which a mat is manufactured by extruding the resultant raw material mixture and a process in which the mat is autoclave-cured at 140-200°C.

Description

  The present invention relates to an inorganic board suitable for a building board and a method for manufacturing the inorganic board.

  Conventionally, there are inorganic boards mainly composed of hydraulic inorganic powder such as cement and wood reinforcing material such as wood pulp fiber. For example, Patent Document 1 discloses a process of kneading a cement-based material, a finely divided siliceous-containing material, a coarsely divided siliceous-containing material, wood powder, pulp, and an appropriate amount of water into a raw material mixture. And a process for extruding the raw material mixture and a process for curing and curing the molded intermediate extruded in the extruding process. Such an inorganic board is excellent in physical properties such as bending strength, and thus is used as a building board for an inner wall material and an outer wall material of a house.

  In recent years, the use of inorganic plates has been expanded and it has been studied to construct the inorganic plates in mid-rise buildings and the like. However, since the height of the mid-rise building is 36 m and its wind pressure is high, it is necessary to improve the wind pressure resistance of the inorganic board for construction. Moreover, since the further improvement of the long-term durability of a house is calculated | required in recent years, the further improvement of long-term durability is calculated | required also to this inorganic board. Note that long-term durability means that deterioration of physical properties and dimensional change are small even after a long period of 10 years or longer.

JP 2008-162833 A

  Therefore, the subject of this invention is providing the inorganic board excellent in wind-pressure resistance and long-term durability, and its manufacturing method.

The inorganic board of the present invention is formed by extruding a raw material mixture composed of cement, a silicic acid-containing material, and organic fibers. In an inorganic board, a cement and a silicic acid containing material are contained in the range of 45: 55-55: 45 by mass ratio, and 3-8 mass% of organic fibers are included with respect to the total solid. The inorganic board has a specific gravity of 1.4 to 2.0, a moisture dimensional change rate of 10 days at 80 ° C. is 0.1% or less, and a water absorption dimensional change rate of 0.1 days or less for 7 days. The dimensional change rate for 7 days in a carbon dioxide concentration 5% environment is 0.1% or less, and the bending strength is 20 N / mm ² or more. The bending strength is a value measured in accordance with JIS A 1408. If it is 20 N / mm ² or more, the wind pressure resistance is such that it passes a wind pressure test under severe conditions of a height of 36 m and a wind pressure of 46 m / min. Excellent. The moisture release dimensional change rate was determined by measuring the length of the specimen (referred to as l ₁ ) after the specimen was brought into an equilibrium state in a constant temperature and humidity chamber at 20 ° C. and a humidity of 60%. Is put into a dryer at 80 ° C., and after 10 days, the specimen is taken out from the dryer, and the length of the specimen (referred to as l ₂ ) is measured again, and (l ₁ -l ₂ ) is determined. The value obtained by multiplying the value divided by l ₂ by 100. The water absorption dimensional change rate was determined by measuring the length of the test body (referred to as l ₃ ) after the test body was brought into an equilibrium state in a constant temperature and humidity chamber at 20 ° C. and a humidity of 60%. After 7 days have passed, the test specimen is taken out of the water, wiped off the water adhering to the surface with a compress, and then the length of the test specimen (referred to as ₄ ) is measured again. l ₄ −l ₃ ) is obtained by multiplying the value obtained by dividing l ₄ −l ₃ ) by l ₃ by 100. The dimensional change rate for 7 days in an environment with a carbon dioxide concentration of 5% is the length of the test specimen (referred to as ₁₅ ) after the specimen is brought into an equilibrium state in a constant temperature and humidity chamber at 20 ° C. and a humidity of 60%. After that, after exposing the specimen for 7 days in a carbon dioxide concentration 5% environment, the length of the specimen (referred to as l ₆ ) is measured again, and (l ₅ -l ₆ ) is determined. the value obtained by dividing the l ₅ is a value obtained by multiplying 100. The moisture dimensional change rate for 10 days at 80 ° C. indicates the degree of dimensional change due to moisture release, and the water absorption dimensional change rate for 7 days indicates the degree of dimensional change due to water absorption. The 7-day dimensional change rate indicates the degree of dimensional change due to carbonation, and the inorganic plate having these values of 0.1% or less has little deterioration over time and is excellent in dimensional stability. . Therefore, even if it passes for a long time after construction, deterioration of a physical property is small, and it is useful as a long-term durable building board. In the inorganic board of the present invention, it is preferable that silica fume is contained as a silicic acid-containing material in an amount of 3 to 15% by mass with respect to the total solid content because the bending strength is excellent. The silicic acid-containing material may be silica fume and silica sand. In addition, it is preferable that the organic fibers are pulp and polypropylene fibers because appropriate deflection is obtained and the workability is excellent. Further, it is preferable that mica is contained in an amount of 3 to 5% by mass based on the total solid content and montmorillonite coated with fatty acid calcium is contained in an amount of 0.5 to 1.5% by mass based on the total solid content because the dimensional stability is excellent. Furthermore, it is preferable for the plate thickness to be 6 to 25 mm because it is easy to transport and work.
The present invention also provides a method for producing an inorganic plate. The method for producing an inorganic board of the present invention includes a step of producing a raw material mixture comprising cement, a silicic acid-containing material, and organic fibers, a step of extruding the obtained raw material mixture to produce a mat, It consists of a curing process. In the step of producing the raw material mixture, the mass ratio of the cement and the silicic acid-containing material in the raw material mixture is 45:55 to 55:45, and the organic fiber content is 3 to 8% by mass with respect to the total solid content. The curing process is performed by curing in an autoclave at 140 to 200 ° C. Thereby, the inorganic board excellent in wind pressure resistance and long-term durability can be manufactured. In the step of producing the raw material mixture, it is preferable that silica fume is contained as a silicic acid-containing material in an amount of 3 to 15% by mass with respect to the total solid content in the raw material mixture because the obtained inorganic plate is excellent in bending strength. The silicic acid-containing material in the raw material mixture may be silica fume and silica sand. In the process of producing the raw material mixture, it is preferable that the organic fiber is pulp and polypropylene fiber because the obtained inorganic plate can be appropriately bent and has excellent workability. Further, in the step of producing the raw material mixture, 3-5% by mass of mica with respect to the total solid content, and 0.5-1.5% by mass of montmorillonite coated with fatty acid calcium with respect to the total solid content are obtained. The inorganic plate to be used is preferable because it has excellent dimensional stability. Furthermore, it is preferable that the plate thickness is 6 to 25 mm because the manufacturing cost is low and the productivity is excellent.

  ADVANTAGE OF THE INVENTION According to this invention, the inorganic board excellent in wind pressure resistance and long-term durability, and its manufacturing method can be provided.

  Hereinafter, embodiments of the present invention will be specifically described.

  The inorganic board of the present invention is formed by extruding a raw material mixture composed of cement, a silicic acid-containing material, and organic fibers.

  Examples of the cement include Portland cement, early strength cement, alumina cement, fly ash cement, blast furnace slag cement, silica cement, and white cement. In the present invention, any one of these substances may be contained, or two or more kinds may be contained.

  Examples of the silicic acid-containing material include quartz sand, quartzite powder, silica powder, silica fume, fly ash, blast furnace slag, shirasu balloon, pearlite, diatomaceous earth and the like. In the present invention, any one of these substances may be contained, or two or more kinds may be contained.

  Organic fibers include natural fibers and synthetic fibers. Natural fibers include animal fibers such as silk, wool, and animal hair, and plant fibers such as wood flour, wood fragments, wood wool, and wood fibers. Wood fibers such as (NBKP), hardwood unbleached kraft pulp (LUKP), hardwood bleached kraft pulp (LBKP) are preferred, and further, when wood fibers having an average fiber length of 0.3 to 1.5 mm are used, strength, etc. It is more preferable because of its excellent physical properties. Examples of the synthetic fiber include polyamide fiber, polyvinyl alcohol fiber, polyester fiber, polypropylene fiber, acrylic fiber, polyurethane fiber, polyolefin fiber, glass fiber, and ceramic fiber. In the present invention, any one of these organic fibers may be contained, or two or more kinds thereof may be contained. It is preferable to use wood fibers and synthetic fibers in combination because they are excellent in physical properties such as strength and deflection.

  Mica can also be used as a raw material other than the above. The mica is preferably a flake having an average particle size of 200 to 700 μm and an aspect ratio of 60 to 100. Mica is preferable because it usually has a layered structure, is not hygroscopic, is a highly elastic body having rigidity, and can improve the dimensional stability of the inorganic board.

  Also, montmorillonite coated with fatty acid calcium can be used. Using montmorillonite coated with fatty acid calcium is preferable because it can reduce the water absorption of the inorganic plate and improve the bending strength and dimensional stability.

  Furthermore, cement compositions can also be used. Examples of the cement composition include a defective board of an inorganic board before curing, a defective board of an inorganic board after curing, a scrap of an inorganic board generated at a construction site, a waste material, and the like. In either case, the powder is pulverized to an average particle size of 50 to 150 μm with an impact pulverizer and / or a rubbing pulverizer. By using the cement composition, the manufacturing cost can be reduced and industrial waste can be reduced.

  Furthermore, cellulose derivatives such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, polyvinyl alcohol, water-soluble polymers, water-absorbing polymers, etc. should be used as extrusion aids in order to reduce extrusion pressure and improve moldability. You can also.

  Furthermore, carboxylic acid-based, sulfonic acid-based, polyethylene glycol-based water reducing agents, plastic foams, lightweight materials such as pulverized plastic foams, calcium chloride, magnesium chloride, potassium sulfate, calcium sulfate, magnesium sulfate, Hardening accelerators such as aluminum sulfate, sodium aluminate, potassium aluminate, calcium formate, calcium acetate, calcium acrylate, water glass, mineral powders such as bentonite and vermiculite, wax, wax, paraffin, silicon, succinic acid, Waterproofing agents such as higher fatty acid metal salts, water repellents, aqueous pastes such as carboxymethylcellulose, reinforcing agents for synthetic resin emulsions such as styrene-butadiene latex and acrylic resin emulsions can also be used.

The inorganic plate of the present invention is formed by extruding a raw material mixture composed of cement, silicic acid-containing material, and organic fiber, and the cement and silicic acid-containing material are in a mass ratio of 45:55 to 55:45. And 3 to 8% by mass of organic fiber based on the total solid content. The specific gravity is 1.4 to 2.0, the moisture dimensional change rate for 10 days at 80 ° C. is 0.1% or less, the water absorption dimensional change rate for 7 days is 0.1% or less, The dimensional change rate for 7 days in a carbon concentration environment of 5% is 0.1% or less, and the bending strength is 20 N / mm ² or more. Although the manufacturing method will be described later, by having such physical properties, the outer wall and the inner wall can be configured as a building board excellent in wind pressure resistance and long-term durability. In addition, although there is no restriction | limiting in plate | board thickness, since manufacturing cost is cheap, it is excellent in productivity, and it is easy to carry and it is easy to construct as it is 6-25 mm.

  When the cement and silicic acid-containing material is contained in a mass ratio of 45:55 to 55:45, the hydrothermal reaction by the autoclave curing proceeds well, the tobermorite generation amount increases, the matrix becomes dense, and the resulting inorganic board Can exhibit sufficient strength and the dimensional change rate is small. The content of the organic fiber is 3 to 8% by mass with respect to the total solid content. If the content is more than 8% by mass, the hardening of the cement is hindered, and the strength of the resulting inorganic board may be reduced. This is because the inorganic plate may not be able to obtain sufficient deflection. Further, it is preferable that mica is contained in an amount of 3 to 5% by mass with respect to the total solid content and montmorillonite coated with fatty acid calcium is contained in an amount of 0.5 to 1.5% by mass with respect to the total solid content, because the dimensional stability is further improved.

And the inorganic board of this invention can be manufactured by extrusion-molding a raw material mixture.
The production method of the present invention includes a step of producing a raw material mixture composed of cement, silicic acid-containing material, and organic fiber, a step of extruding the obtained raw material mixture to produce a mat, and a step of curing the mat. It consists of.

  The step of producing the raw material mixture is performed by mixing and kneading cement, silicic acid-containing material, organic fibers, and an appropriate amount of water. The kneading is preferably performed with a kneader. In addition, a raw material mixture is adjusted so that solid content concentration may be 67-83 mass%. The reason why the solid content concentration of the raw material mixture is 83% by mass or less is that when it is more than 83% by mass, it is difficult to extrude and the productivity is poor, and 67% by mass or more is 67% by mass. If it is less, the specific gravity of the mat obtained by extrusion molding will be low, and it will take time for dehydration, resulting in poor productivity.

  In the process of manufacturing the mat by extruding the obtained raw material mixture, the raw material mixture adjusted to the above-mentioned solid content concentration is filled into the extruder and extruded from the die of the extruder to produce a plate-like mat. Is done. The extrusion pressure is usually 0.5-3 MPa. In addition, the obtained mat | matte can also press a template on the surface and can also form an uneven | corrugated pattern.

  The step of curing the mat is performed by curing at 140 to 200 ° C. The autoclave curing is performed at a pressure of 0.5 MPa or more for 7 to 15 hours. By this autoclave curing, the hydrothermal reaction proceeds favorably, the amount of tobermorite produced increases, the matrix becomes dense, and the resulting inorganic plate can exhibit sufficient strength and the dimensional change rate becomes small. Furthermore, it is preferable to perform autoclave curing after steam curing at 100 ° C. or lower because it is excellent in productivity and physical properties of the resulting inorganic plate.

  Next, examples of the present invention will be given.

  Example 1 Portland cement, silica sand, pulp, and the like were mixed and kneaded to form a raw material mixture. The raw material mixture was extruded from a die of an extruder to form a plate-like mat. To 7 and Comparative Examples 1 to 4 were produced. Table 1 shows the ratio of each raw material to the total solid content of the raw material mixture, the solid content concentration, and the autoclave curing temperature.

  And about each obtained inorganic board of Examples 1-7 and Comparative Examples 1-4, specific gravity, thickness, bending strength, moisture dimensional change rate for 10 days at 80 ° C, water absorption dimensional change rate for 7 days, Since the dimensional change rate was measured for 7 days in an environment with a carbon dioxide concentration of 5%, the results are also shown in Table 1.

The inorganic plates of Examples 1 to 7 had a specific gravity of 1.4 to 1.6, a bending strength greater than 20 N / mm ² , and excellent bending strength. Also, the dimensional change rate for 10 days at 80 ° C., the dimensional change rate for water absorption for 7 days, and the dimensional change rate for 7 days in an environment with a carbon dioxide concentration of 5% are all less than 0.1%. Also excellent.
On the other hand, the inorganic board of Comparative Example 1 containing cement and silicic acid-containing material at a mass ratio of 70:30 has a large dimensional change rate of 0.15% for 7 days in an environment with a carbon dioxide concentration of 5%, and dimensional stability. Inferior to
The inorganic board of Comparative Example 2 containing 10% by mass of pulp and polypropylene fibers had a specific gravity as low as 1.21 and a bending strength lower than 20 N / mm ² . In addition, the dimensional change rate of moisture release for 10 days at 80 ° C., the dimensional change rate of water absorption for 7 days, and the dimensional change rate for 7 days in an environment with a carbon dioxide concentration of 5% are all greater than 0.1%, and thus dimensional stability inferior.
The inorganic plate of Comparative Example 3 produced at an autoclave curing temperature of 120 ° C. had a bending strength lower than 20 N / mm ² . Further, the dimensional change rate for water absorption for 7 days and the dimensional change rate for 7 days in an environment with a carbon dioxide concentration of 5% were larger than 0.1%, and the dimensional stability was poor.
The inorganic board of Comparative Example 4 produced from the raw material mixture at a solid content concentration of 65% by mass has a low specific gravity of 1.12, a bending strength of less than 20 N / mm ² , and a carbon dioxide concentration of 5% for 7 days. The rate of dimensional change was greater than 0.1%.

  Although one embodiment of the present invention has been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the invention described in the claims.

  As described above, according to the present invention, an inorganic plate excellent in wind pressure resistance and long-term durability, and a method for producing the same can be provided.

Claims (10)

An inorganic plate formed by extruding a raw material mixture composed of cement, silicic acid-containing material, and organic fiber,
Containing cement and silicic acid-containing material in a mass ratio of 45:55 to 55:45,
Containing 3 to 8% by mass of organic fiber based on the total solid content,
The specific gravity is 1.4 to 2.0,
The rate of change in the moisture release dimension at 80 ° C. for 10 days is 0.1% or less,
7 day water absorption dimensional change rate is 0.1% or less,
The dimensional change rate for 7 days in a carbon dioxide concentration 5% environment is 0.1% or less,
An inorganic plate having a bending strength of 20 N / mm ² or more. Silica fume is contained as a silicic acid-containing material in an amount of 3 to 15% by mass based on the total solid content. The inorganic board according to claim 2, wherein the silicic acid-containing material is silica fume and silica sand. The inorganic board according to claim 1, wherein the organic fibers are pulp and polypropylene fibers. Containing 3 to 5% by mass of mica based on the total solid content,
The inorganic board according to claim 1, comprising montmorillonite coated with fatty acid calcium in an amount of 0.5 to 1.5 mass% based on the total solid content. Producing a raw material mixture comprising cement, silicic acid-containing material, and organic fiber;
Extruding the obtained raw material mixture to produce a mat; and
The process of curing the mat,
In the step of producing the raw material mixture, the mass ratio of the cement and the silicic acid-containing material in the raw material mixture is 45:55 to 55:45, and the organic fiber content is 3 to 8% by mass with respect to the total solid content.
The process of curing is performed by curing in an autoclave at 140 to 200 ° C. A method for producing an inorganic board. In the process of manufacturing a raw material mixture, 3-15 mass% of silica fume is contained as a silicic acid containing material with respect to the total solid in a raw material mixture. The manufacturing method of the inorganic board of Claim 6 characterized by the above-mentioned. In the process of manufacturing a raw material mixture, the silicic acid containing material in a raw material mixture is made into a silica fume and silica sand. The manufacturing method of the inorganic board of Claim 7 characterized by the above-mentioned. In the process of manufacturing a raw material mixture, an organic fiber is made into a pulp and a polypropylene fiber. The manufacturing method of the inorganic board of Claim 6 characterized by the above-mentioned. In the step of producing the raw material mixture, mica is contained in 3 to 5% by mass with respect to the total solid content, and montmorillonite coated with fatty acid calcium is contained in an amount of 0.5 to 1.5% by mass with respect to the total solid content. The manufacturing method of the inorganic board of Claim 6.