JP2012153574A - Inorganic board, and method for producing the inorganic board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic board excellent in bending strength and dimensional stability, and to provide a method for producing the inorganic board.SOLUTION: The inorganic board formed by laminating each layer comprising cement, a silicic acid inclusion and a woody reinforcing material has following properties, namely, the specific gravity is 1.5-2.0, a moisture desorption dimensional change rate of 10 days at 80°C is ≤0.1%, a water absorption dimensional change rate of 7 days is ≤0.1%, a dimensional change rate of 7 days under an environment of 5% carbon dioxide concentration is ≤0.1%, and the bending strength is ≥20 N/mm. The method for producing the inorganic board has processes of: producing raw material slurry comprising cement, a silicic acid inclusion and a woody reinforcing material; papermaking a sheet from the acquired raw material slurry to produce a lamination mat; and pressing the lamination mat at pressure of ≥50 kg/cm, and curing it by an autoclave at 170-200°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 that a raw material mixture mainly composed of cements and fiber materials is further added with an inorganic hollow filler subjected to alkali treatment to form a slurry, and a plurality of mats obtained by papermaking and dewatering are laminated to form a laminated mat. The manufacturing method of the inorganic board which makes this lamination | stacking mat | matte cure curing is disclosed. 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.

  However, in recent years, it has been studied to expand the use of the inorganic board and construct the inorganic board in a mid-rise building or 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. Furthermore, 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 for this inorganic board.

JP-A-9-227200

  Among the physical properties of inorganic plates, bending strength greatly contributes to earthquake resistance and wind resistance, and dimensional stability greatly contributes to long-term durability of inorganic plates. Therefore, to improve the wind pressure resistance of the inorganic plate, it is necessary to have excellent bending strength, and to improve long-term durability, it is necessary to have excellent dimensional stability. Therefore, the subject of this invention is providing the inorganic board excellent in bending strength and dimensional stability, and its manufacturing method.

The inorganic board of the present invention is formed by laminating layers made of cement, silicic acid-containing material, and wood reinforcing material, and has a specific gravity of 1.5 to 2.0 and a moisture release dimensional change rate for 10 days at 80 ° C. Is 0.1% or less, the dimensional change rate for water absorption for 7 days is 0.1% or less, the dimensional change rate for 7 days in an environment with a carbon dioxide concentration of 5% 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. Moreover, in the inorganic board of the present invention, when the cement and silicic acid-containing material is contained in a mass ratio of 35:65 to 45:55 and the wood reinforcing material is contained in an amount of 7 to 10% by mass, the inorganic board has a bending strength. It is preferable because the deflection and the dimensional change rate are particularly excellent. Furthermore, it is preferable that the wood reinforcing material is a softwood pulp, or a softwood pulp and waste paper because an appropriate deflection can be obtained in the inorganic board. Furthermore, it is preferable that mica is contained in an amount of 3 to 5% by mass because the dimensional stability is further improved.
The present invention also provides a method for producing an inorganic plate. The method for producing an inorganic board according to the present invention includes a step of producing a raw material slurry made of cement, a silicic acid-containing material, and a wood reinforcing material, a step of making the obtained raw material slurry to produce a laminated mat, and a laminated mat The process of pressing and curing. In the step of pressing and curing, the pressing pressure is 50 kg / cm ² or more, and curing is performed at 170 to 200 ° C. in an autoclave. Thereby, the inorganic board excellent in bending strength and long-term durability can be manufactured. In the step of producing the laminated mat, the production of the laminated mat is preferably carried out by laminating sheets obtained by papermaking and pressure dehydrating the raw slurry. Moreover, in the process of manufacturing the raw material slurry, the mass ratio of the cement and the silicic acid-containing material in the raw material slurry is 35:65 to 45:55, and the wood reinforcing material is 7 to 10% by mass with respect to the solid content of the raw material slurry. Then, since the obtained inorganic board is especially excellent in bending strength, a bending, and a dimensional change rate, it is preferable. Furthermore, in the process of producing the raw material slurry, it is preferable to use soft wood pulp or soft wood pulp and waste paper as the wood reinforcing material in the raw material slurry, since an appropriate deflection can be obtained in the inorganic board. Furthermore, in the step of producing the raw material slurry, it is preferable that mica is contained in the raw material slurry in an amount of 3 to 5% by mass relative to the solid content because the dimensional stability is further improved.

  ADVANTAGE OF THE INVENTION According to this invention, the inorganic board excellent in bending strength and dimensional stability, 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 laminating a plurality of layers made of cement, silicic acid-containing material, and wood reinforcing material.

  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.

  Examples of the wood reinforcing material include waste paper, softwood unbleached kraft pulp (NUKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), and hardwood bleached kraft pulp (LBKP). In the present invention, any one of these substances may be contained, or two or more kinds may be contained. Further, it is preferable to use a wood reinforcing material beaten with a beater such as a disc refiner to make Canadian freeness 300 to 600 ml since physical properties such as strength are improved.

  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, has no hygroscopic property, is a highly elastic body having rigidity, and can greatly improve the dimensional stability of the inorganic board.

  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, hardening accelerators such as calcium chloride, magnesium chloride, potassium sulfate, calcium sulfate, magnesium sulfate, aluminum sulfate, sodium aluminate, potassium aluminate, calcium formate, calcium acetate, calcium acrylate, water glass, bentonite, vermiculite Mineral powder such as wax, wax, paraffin, silicon, succinic acid, metal salt of higher fatty acid, water repellent, foaming thermoplastic beads, plastic foam, nylon, polyvinyl alcohol fiber , Polyester fibers, polypropylene fibers, acrylic fibers, polyurethane fibers, glass fibers and other chemical fibers, polyvinyl alcohol, carboxymethyl cellulose and other aqueous pastes, styrene-butadiene latex, acrylic resin emma Reinforcing agent of the synthetic resin emulsions such as John can also be used.

And the inorganic board of this invention laminates | stacks the layer which consists of a cement, a silicic acid containing material, and a wooden reinforcement, and specific gravity is 1.5-2.0, and it is a moisture release dimension for 10 days at 80 degreeC. The rate of change is 0.1% or less, the dimensional change rate for water absorption for 7 days is 0.1% or less, the dimensional change rate for 7 days in an environment with a carbon dioxide concentration of 5% is 0.1% or less, and bending The strength is 20 N / mm ² or more. Although the manufacturing method is mentioned later, an outer wall and an inner wall can be comprised as a building board excellent in bending strength and long-term durability by having such a physical property.

  In addition, in the inorganic board of this invention, it is preferable to contain a cement and a silicic acid containing material in the range of 35: 65-45: 55 by mass ratio, and to contain 7-10 mass% of wood reinforcement materials. When the cement and silicic acid-containing material is contained in a mass ratio of 35:65 to 45:55, the hydrothermal reaction by autoclave curing proceeds well, the amount of tobermorite is increased, the matrix is densified, and the resulting inorganic board Can exhibit sufficient strength and the dimensional change rate is small. When the content of the wood reinforcing material is 7 to 10% by mass, if it exceeds 10% by mass, the hardening of the cement may be hindered, and the strength of the resulting inorganic plate may be reduced. This is because sufficient deflection may not be obtained. Furthermore, it is preferable that mica is contained in an amount of 3 to 5% by mass because the dimensional stability is further improved.

And the inorganic board of this invention can be manufactured with a wet manufacturing method.
The production method of the present invention includes a step of producing a raw material slurry made of cement, a silicic acid-containing material, and a wood reinforcing material, a step of making the obtained raw material slurry to produce a laminated mat, and pressing the laminated mat. And the curing process.

  The step of producing the raw material slurry is performed by mixing cement, silicic acid-containing material, and wood reinforcing material. The cement, the silicic acid-containing material, and the wood reinforcing material may be added in a powder (dry) state, or may be added after mixing each raw material in separate water in advance. It adjusts so that solid content concentration may be 20 mass% or less. The reason why the solid content concentration of the slurry is 20% by mass or less is that when it exceeds 20% by mass, it takes time to dehydrate the slurry, and the dehydrated paper sheet is prone to cracking and difficult to produce. It is to do.

  In the process of producing the obtained raw material slurry and manufacturing the laminated mat, first, the slurry is separated into water and solid using a felt, a wire net or the like. Specifically, the slurry can be flowed down on the felt to dehydrate the slurry, or the slurry can be dehydrated by swirling it with a circular wire mesh. And a lamination mat is manufactured by laminating another papermaking sheet on the papermaking sheet obtained. A method for laminating a papermaking sheet is prepared by preparing a plurality of machines for producing a papermaking sheet in the conveying direction of the papermaking sheet, a method for laminating the papermaking sheets produced by each apparatus, a papermaking sheet is wound around a roll and laminated, Can be obtained by removing from the roll.

The step of pressing and curing the obtained laminated mat is performed by pressing the laminated mat at a pressure of 50 kg / cm ² or more and then curing the autoclave. In the pressing, a template may be disposed on or under the laminated mat to form a concavo-convex pattern on the surface of the laminated mat. The autoclave curing is performed at 170 to 200 ° C. and a pressure of 0.5 MPa or more for 7 to 15 hours.

  Next, examples of the present invention will be given.

  By mixing Portland cement, silica sand, wood reinforcing material, and water to form a slurry, the slurry is allowed to flow onto a dewatering felt, the paper sheet is shaped while dewatering, and the paper sheet is rolled up by a roll The resulting laminated mats were pressed and autoclaved to produce inorganic plates of Examples 1 to 6 and Comparative Examples 1 to 5. Table 1 shows the ratio of each raw material to the total solid content of the slurry, the solid content concentration, the press pressure, and the autoclave curing temperature. Examples 1, 2, 4 to 6 and Comparative Examples 1 to 4 were blended with unbleached kraft pulp of Canadian freeness 450 ml as a wood reinforcing material. In Example 3 and Comparative Example 5, 450 ml of Canadian freeness conifer Unbleached kraft pulp and waste paper were blended. In Examples 1 and 3-6 and Comparative Examples 1 and 3-5, mica was further blended.

  And about each obtained inorganic board of Examples 1-6 and Comparative Examples 1-5, 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 6 having a press pressure of greater than 50 kg / cm ² and an autoclave curing temperature of 170 ° C. or higher have a specific gravity of 1.5 to 1.6 and a bending strength of greater than 20 N / mm ² , Excellent bending strength. Also, the dimensional change rate for moisture release at 80 ° C. for 10 days, 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 plate of Comparative Example 1 having a press pressure of 40 kg / cm ² and an autoclave curing temperature of 100 ° C. has a low specific gravity of 1.35, a bending strength of less than 20 N / mm ² , and 80 days at 80 ° C. The dimensional change rate for moisture release, 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 all greater than 0.1%.
Although the press pressure is 100 kg / cm ² and the autoclave curing temperature is 180 ° C., the inorganic board of Comparative Example 2 containing 11% by mass of unexposed softwood and kraft pulp has a specific gravity of 1.41 and a bending strength of 20 N / smaller than mm ^2, desorption rate of dimensional change 10 days at 80 ° C., 7 days water dimensional change, either 7 days dimensional change under carbon dioxide concentration of 5% environmental was greater than 0.1% .
Although the press pressure is 100 kg / cm ² and the autoclave curing temperature is 180 ° C., the inorganic board of Comparative Example 3 containing 44.5% by mass of Portland cement and 44.5% of silica sand is released at 80 ° C. for 10 days. Wet dimensional change rate, 7 day water absorption dimensional change rate, carbon dioxide concentration 5% 7 day dimensional change rate was 0.1% or less, bending strength was less than 18.4 N / mm ² , Bending strength was inferior.
Although the press pressure is 100 kg / cm ² and the autoclave curing temperature is 180 ° C., the inorganic plate of Comparative Example 4 containing 10% by mass of mica has a specific gravity as low as 1.33 and a bending strength of 20 N / mm ^{2 or} less. The dimensional change rate of moisture release at 80 ° C. for 10 days, 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% were all greater than 0.1%.
Although the press pressure is 100 kg / cm ² and the curing temperature of the autoclave is 180 ° C., the inorganic board of Comparative Example 5 containing 8.0% by mass of waste paper and 3.0% of mica is dehumidified at 80 ° C. for 10 days. The dimensional change rate, 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 all less than 0.1%, and these properties were excellent, but the bending strength was 20 N / mm. ^{It was} less than ² and was inferior in bending strength.

  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, it is possible to provide an inorganic plate excellent in bending strength and dimensional stability, and a method for producing the same.

Claims (11)

It is an inorganic board formed by laminating layers made of cement, silicic acid-containing material, and wood reinforcing material,
The specific gravity is 1.5 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. Containing cement and silicic acid-containing material in a mass ratio of 35:65 to 45:55;
The inorganic board according to claim 1, comprising 7 to 10% by mass of a wood reinforcing material. The inorganic board according to claim 1, wherein the wood reinforcing material is softwood pulp. The inorganic board according to claim 1, wherein the wood reinforcing material is softwood pulp and waste paper. Furthermore, 3-5 mass% of mica is contained. The inorganic board of Claim 1 characterized by the above-mentioned. A step of producing a raw material slurry comprising cement, silicic acid-containing material, and wood reinforcing material;
Making the obtained raw material slurry and manufacturing a laminated mat;
It consists of the process of pressing and curing the laminated mat,
In the step of pressing and curing, the pressing pressure is 50 kg / cm ² or more, and curing is performed at 170 to 200 ° C. in an autoclave. The method for producing an inorganic board according to claim 6, wherein in the step of producing a laminated mat, the production of the laminated mat is carried out by making sheets of raw material slurry and laminating sheets obtained by pressure dehydration. . In the step of producing the raw material slurry, the mass ratio of the cement and the silicic acid-containing material in the raw material slurry is 35:65 to 45:55, and the wood reinforcing material is 7 to 10% by mass with respect to the solid content of the raw material slurry. The manufacturing method of the inorganic board of Claim 6 characterized by these. The method for producing an inorganic board according to claim 6, wherein in the step of producing the raw material slurry, the wood reinforcing material in the raw material slurry is softwood pulp. The method for producing an inorganic board according to claim 6, wherein in the step of producing the raw material slurry, the wood reinforcing material in the raw material slurry is softwood pulp and waste paper. The method for producing an inorganic plate according to claim 6, wherein in the step of producing the raw slurry, mica is contained in the raw slurry in an amount of 3 to 5% by mass relative to the solid content.