JP2009226906A - Method for manufacturing inorganic plate by papermaking process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a thin inorganic plate by a papermaking process which shows small deflection due to its own weight in spite of thinness, and good handleability in transportation and application leading to easy work. <P>SOLUTION: The manufacturing method of the thin inorganic plate by the papermaking process comprises a step of obtaining slurry by wet-mixing a formulation comprising 20-60 mass% hydratable raw material for forming a matrix, 3-11 mass% natural fiber having a degree of filtrated water in a range of 150-450 ml according to the Canadian standard freeness and/or 0.5-5 mass% inorganic fiber (excluding asbestos) and/or synthetic fiber having a fiber length in a range of 6.0-0.2 mm and a fiber diameter in a range of 20-50 μm (provided that the total of the natural fiber and inorganic fiber and/or synthetic fiber is 3.5-12 mass%), 10-50 mass% calcium silicate hydrate having an average particle size in a range of 30-100 μm and obtained in advance by hydrothermal synthesis of a calcareous material and a siliceous material, 1-50 mass% inorganic filler and 1-20 mass% silica fume; a step of obtaining a green plate by papermaking process of the obtained slurry; and a step of dehydrating the green plate by pressurization with the holding pressure exceeding 30 N/mm<SP>2</SP>up to 40 N/mm<SP>2</SP>and ageing to harden it to obtain a hardened body with a thickness of 2-4 mm and apparent density of 1.2-1.5 g/cm<SP>3</SP>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing an inorganic papermaking plate, and more particularly to a method for producing a thin inorganic papermaking plate.

At present, inorganic boards used as general building materials include, for example, cement-based, gypsum-based, and calcium silicate-based materials. These inorganic plates are usually produced by methods such as papermaking and press molding.
As raw materials for inorganic boards, cement-based, gypsum-based and calcium silicate-based materials usually use matrix forming raw materials and fiber raw materials as essential raw materials, and together with these essential raw materials, an inorganic filler for imparting necessary performance. Used together. Conventionally, asbestos has been used as a fiber raw material. Asbestos is a very suitable fiber for the production and performance of inorganic board, but it has been pointed out that its effects on health. Therefore, asbestos can be manufactured in various ways to produce inorganic board without using asbestos and obtain the required performance. Technology development has been carried out.

  For example, in Non-Patent Document 1, cellulose fiber such as wood pulp is used as a fiber raw material in decalcification of a calcium silicate plate, but using cellulose fiber makes the calcium silicate plate flexible. It is described that it is suitable for curved surface construction and the like.

Further, for example, with respect to a method for producing a fiber-reinforced inorganic plate by a papermaking method, Patent Document 1 discloses a hydrated raw material for forming a matrix of 20 to 60% by mass; an inorganic filler of 1 to 50% by mass; Inorganic fiber and / or synthetic fiber 0.5 in the range of natural fiber 3-11 mass% and fiber length 6.0-0.2 mm, fiber diameter 20-50 μm in the range of 150-450 ml with standard freeness Reinforcing fibers composed of ˜5% by mass (excluding asbestos) 3.5˜12% by mass; and an average particle diameter obtained by hydrothermal synthesis of a calcareous raw material and a siliceous raw material in advance within a range of 30 μm to 100 μm A slurry containing 10 to 50% by mass of calcium silicate hydrate is obtained by wet mixing to obtain a slurry, and the resulting slurry is subjected to a thin film dehydration rate of 5 on an endless felt. The apparent density of the green plate after separation from the making roll is set to 0.35 to 0.65 g by adjusting the moisture content of the thin film when wound on the making roll to 100 to 180% within the range of 30% / second. A green plate is obtained by papermaking within the range of / cm ^3, the green plate is pressure dehydrated, and the apparent density of the green plate after pressure dehydration is 1.3 of the apparent density of the green plate before pressure dehydration. A surface comprising an inorganic papermaking plate obtained by curing and curing after being within a range of ~ 2.0 times, and a moisture-permeable surface decorative layer provided on at least one surface of the substrate The decorative inorganic papermaking board (Claim 1); The surface decorative inorganic papermaking board (Claim 2) according to claim 1, comprising a permeable sealer layer between the base material and the permeable surface decorative layer. The paper making method of the inorganic paper making plate used as a material is the round net paper making method. , Surface decorative inorganic papermaking board according to claim 1, wherein (claim 3) is disclosed. The paragraph [0035] of Patent Document 1 states that “pressure dehydration of the green plate can be performed using a pressure dehydration apparatus such as a known press machine. , Holding pressure, holding time, etc.) must be determined so that the apparent density of the green plate after pressure dehydration is within a range of 1.3 to 2.0 times the apparent density of the green plate before pressure dehydration. As a method for determining the conditions for pressure dehydration, for example, prior to actual production, the raw slurry is dehydrated at 5 to 30% / second by a suction dehydration test simulating papermaking, and the apparent density is 0.35. A green plate of 0.65 g / cm ³ is prepared and subjected to a pressure dehydration test. The apparent density of the green plate after pressure dehydration is 1.3-2. The pressure dehydration conditions may be determined so that the pressure is within the range of 0. Therefore, the pressure dehydration conditions are defined as a specific range. But it is not limited to, holding pressure is generally a 5 to 30 N / mm ^2, the product of the holding pressure (N / mm ²⁾ and retention time (in seconds) is approximately at 1000~40000N / mm ² · sec There is also a statement to the effect.

Furthermore, as an aqueous coating composition for providing a moisture-permeable coating film on the surface of a concrete structure, for example, Patent Document 2 discloses that a solid content in the aqueous coating composition is 100 parts by weight (parts by mass), and an alkylalkoxysilane is dispersed in water. Body (a) 15-47 parts by weight (parts by mass), fluorine emulsion (b) 8-27 parts by weight (parts by mass), fluorine pendant acrylic polymer (c) 9-27 parts by weight (parts by mass), and pigment (d 1) to 35 parts by weight (parts by mass) of an aqueous coating composition (Claim 1); further comprising 0.1 to 2 parts by weight (parts by mass) of a bioinert agent. The water-based paint composition according to claim 1 or 2, further comprising a polar organic solvent and / or a thickener in a total amount of 3 to 10% by weight (mass%). Composition (Claim 3); Claim 1 to a coating film obtained by coating the aqueous coating composition according to any one of 3, 23 ° C., moisture permeation amount 30 to 40 g / m ² per 24 hours at 50% humidity A moisture-permeable coating film (Claim 4) is disclosed.

Compositions, Vol. 13, no. 2 [April 1982] 123-128 “Developing asbestos-free calcium silicate building boards” JP, 2007-1043, A Claims [0035] JP, 2001-348529, A Claim

  However, the description of Non-Patent Document 1 suggests that the deflection of the calcium silicate plate using cellulose fibers increases, particularly when the thickness of the calcium silicate plate is thin. There was a problem that it was extremely large, warped during construction, and difficult to construct. Also for the surface-decorated inorganic papermaking plate disclosed in Patent Document 1, in the case of a thin object, the deflection due to its own weight is large, the handling property during transportation and construction is poor, and the problem that it is difficult to work has not been solved.

  Accordingly, an object of the present invention is to provide a method for producing a thin inorganic papermaking plate that is easy to work with little handling due to its own weight, good handling properties during transportation and construction, even if it is a thin material.

That is, the present invention relates to 20 to 60% by mass of a hydratable raw material for forming a matrix; 3 to 11% by mass of natural fibers having a freeness within a range of 150 to 450 ml in Canadian standard freeness and / or a fiber length of 6.0 to 6.0 2. 0.5 to 5% by mass of inorganic fiber and / or synthetic fiber (excluding asbestos) in the range of 0.2 mm and fiber diameter of 20 to 50 μm, provided that the total amount of natural fiber and inorganic fiber and / or synthetic fiber 5 to 12% by mass; calcium silicate hydrate 10 to 50% by mass having an average particle diameter in the range of 30 μm to 100 μm obtained by hydrothermal synthesis of a calcareous raw material and a silicic raw material in advance; inorganic filler 1 ~ 50% by mass; and a composition containing 1 to 20% by mass of silica fume is wet-mixed to obtain a slurry, and a green board is obtained by making the resulting slurry, and the green board is subjected to pressure dehydration. of After pressurizing圧脱water until lifting pressure 30 N / mm ² exceeding 40N / mm ^2, a thickness of 2~4mm by curing curing, characterized by obtaining a cured product of an apparent density 1.2~1.5g / cm ³ The present invention relates to a method for producing a thin inorganic papermaking plate.

  According to the method for producing a thin inorganic papermaking plate of the present invention, even if it is a thin material, there is little deflection due to its own weight, a handling property during transportation and construction is good, and a thin inorganic papermaking plate that is easy to work with can be produced.

Hereinafter, the manufacturing method of the thin inorganic papermaking board of this invention is demonstrated in detail.
According to the method for producing a thin inorganic papermaking plate of the present invention, a hydrated raw material for forming a matrix is 20 to 60% by mass; a natural fiber having a freeness in the range of 150 to 450 ml in Canadian standard freeness is 0.5 to 5% by mass. And / or a fiber length of 6.0 to 0.2 mm, and an inorganic fiber and / or synthetic fiber (excluding asbestos) in the range of a fiber diameter of 20 to 50 μm, 0.5 to 5% by mass, provided that the natural fiber and the inorganic fiber / Or total amount of synthetic fiber 3.5 to 12% by mass; calcium silicate hydrate 10 having an average particle diameter in the range of 30 μm to 100 μm obtained by hydrothermal synthesis of a calcareous raw material and a siliceous raw material in advance -50% by mass; 1-50% by mass of an inorganic filler; and a composition comprising 1-20% by mass of silica fume and wet-mixing to form a slurry, pressure dehydration, and curing and curing. It is possible to manufacture an inorganic papermaking plate.

Here, the hydratable raw material for forming the matrix may be either hydraulic or pneumatic, and is not particularly limited, but a hydraulic cement is suitable because of its high strength expression power, for example, Examples include ordinary Portland cement, early-strength cement, blast furnace cement, low heat cement, and ecocement. Examples of the air-cement cement include gypsum-based materials such as hemihydrate gypsum and type II anhydrous gypsum. When a gypsum-based material is used, a predetermined amount of a curing retarder (citric acid, phthalic acid, tartaric acid, etc.) or a curing accelerator (alkali continuous sulfates such as sodium sulfate) can be added as necessary. The specific surface area of the matrix-forming water-dispersible material in the case of hydraulic cement, 2500~5000cm ² / g, is preferably in the range of 3000~4000cm ² / g, when the air-hardening cement, 4000～8000Cm ² / G, preferably in the range of 4500 to 6500 cm ² / g.

  The reinforcing fibers include, for example, natural fibers such as wood pulp and various hemp, inorganic fibers such as glass fibers, rock wool, ceramic wool, and carbon fibers, artificial pulp, polyvinyl alcohol, polypropylene, polyethylene, polyester, acrylic, and rayon. Synthetic fibers such as Among these, from the viewpoint of further improving the bending strength and impact resistance performance, it is preferable to use cellulosic fibers such as wood pulp as the main component of the reinforcing fibers. In addition, the freeness of natural fibers is in the range of 150 to 450 ml, preferably 150 to 350 ml in terms of Canadian standard freeness (hereinafter referred to as “CSF”) defined in JIS P8121. The CSF can be adjusted by beating a reinforcing fiber, such as wood pulp, with a refiner or the like wet. The beating treatment increases the branching of the fibers, so-called fibrillation, and as a result, it is possible to improve adhesion and flexibility with the matrix formed by hydrating the hydratable raw material for matrix formation. . Here, by setting the CSF to 450 ml or less, sufficient adhesion between the reinforcing fiber and the matrix is achieved, good dispersion of the reinforcing fiber is obtained, and high strength is imparted to the product (inorganic papermaking board). Can do. In addition, by increasing the CSF to 150 ml or more, the drainage of the slurry is increased, dehydration unevenness at the time of pressure dehydration, blistering, tearing, etc. are prevented, and good flexibility and consequently impact resistance performance is imparted to the product. Can do.

  The fiber length of the inorganic fiber and the synthetic fiber is 6.0 to 0.2 mm, preferably 4.0 to 0.5 mm, and the fiber diameter is 20 to 50 μm, preferably 20 to 40 μm. Is within.

  Further, the inorganic filler is not particularly limited as long as it is generally used for an inorganic board. For example, fillers for improving heat resistance such as mica and wollastonite, dihydrate gypsum and calcium carbonate. Non-hydratable raw materials such as fillers for improving fire resistance such as fillers and fillers for preventing cracks such as silica can be used. In addition, these can also use 2 or more types together.

In addition, calcium silicate hydrate can be produced by mixing a calcareous raw material and a siliceous raw material together with water and hydrothermal synthesis under high temperature and high pressure.
Examples of the calcareous raw material include quick lime and slaked lime, and examples of the siliceous raw material include quartzite, diatomaceous earth, silica fume and the like. Silica stone is particularly preferable.
The synthesis of calcium silicate hydrate can be performed, for example, as follows. The calcareous raw material and the siliceous raw material are, for example, blending ratio (CaO / SiO ₂ molar ratio) of 0.5 to 1.5, preferably 0.5 to 1.2. 5 to 20 times, preferably 7 to 16 times, water is added, mixed and dispersed to form a raw material slurry, and the raw material slurry is stirred at a temperature of 150 to 230 ° C., preferably 170 to 210 ° C. The hydrothermal synthesis is performed for 1 to 20 hours, preferably 3 to 12 hours. In this way, calcium silicate hydrate is obtained as, for example, tobermorite, zonotrite and the like. The average particle size of calcium silicate hydrate is in the range of 30 μm to 100 μm, preferably 50 μm to 90 μm.

  In addition, the said average particle diameter can be adjusted with the particle size of a siliceous raw material, the ratio of the water used, the degree of stirring in a pressure vessel, etc. For example, the particle size of the siliceous material is 80 μm or less, preferably 60 μm or less, and the amount of water used is 7 to 16 times the mass ratio of the mixture of the calcareous material and the siliceous material, and is provided in the pressure vessel. By setting the peripheral speed of the obtained stirring rotary blade to 100 to 200 m / min, the average particle diameter of the obtained calcium silicate hydrate can be adjusted in the range of 30 to 100 μm as described above. In addition, the average particle diameter of the calcium silicate hydrate prescribed | regulated by this specification is calculated | required with the particle size distribution measuring apparatus by a laser diffraction scattering method.

Silica fume also acts as a hydrating auxiliary material. Silica fume is a by-product generated during the manufacture of metals such as silicon and silicon alloys, and is an ultrafine particle material having a specific surface area of 8 to ²⁰ m ² / g mainly composed of amorphous silica. Silica fume acts as a hydratable auxiliary material because it reacts with free lime produced by the hydration reaction of cement and pozzolanic.

  The various raw materials are 20 to 60% by mass, preferably 30 to 60% by mass of a hydratable raw material for matrix formation, and 30 to 60% by mass as a mass ratio with respect to the obtained thin inorganic paper-making board, and natural raw materials and inorganic fibers and / or synthetic fibers. (Total amount) 3.5-12% by mass, preferably 5-12% by mass, calcium silicate hydrate 10-50% by mass, preferably 10-30% by mass, inorganic filler 1-50% by mass, preferably It is preferable to mix 1 to 30% by mass and 1 to 20% by mass of silica fume, preferably 5 to 15% by mass. The reinforcing fiber has a freeness of 3 to 11% by mass, preferably 4 to 8% by mass and a fiber length of 6.0 to 0.2 mm, and a fiber diameter of 20 within a CSF range of 150 to 450 ml. It is composed of 0.5 to 5% by mass, preferably 0.5 to 3% by mass of inorganic fiber and / or synthetic fiber in the range of ˜50 μm, and the total amount of natural fiber and inorganic fiber and / or synthetic fiber is the above It mix | blends so that it may become in the range.

  The manufacturing method of the thin inorganic papermaking board of this invention mix | blends said various materials, Preferably in the said mixture ratio, there are 7-30 times (mass ratio) of various materials, Preferably it is 10-20 times water. Is added and wet-mixed to make a slurry, and the resulting slurry is made into paper to obtain a green plate. After the resulting green plate is dehydrated under pressure, it can be cured by curing.

  In addition, as the papermaking method referred to in this specification, any papermaking method known in the art can be applied, and examples thereof include a round net type papermaking method, a long net type papermaking method, and a flow-on type papermaking method. For example, in the round net making method, the raw slurry is made with a wire mesh cylinder to form a green film (thin film), and the resulting green film is transferred to an endless felt, dehydrated on the endless felt, and applied to a making roll. The green sheet (raw board) is obtained by winding up to a thickness of 1 mm and separating from the making roll when the thickness reaches a predetermined thickness. In addition, the flow-on type papermaking method supplies raw slurry directly onto the endless felt, dehydrates it on the endless felt to form a green film (thin film), winds it up to a predetermined thickness on a making roll, When the thickness is reached, the green sheet (raw board) is obtained by separating from the making roll. Among them, the round net type papermaking method is preferable from the viewpoint that the production efficiency is high, the production of thin objects is possible, and the two-dimensional orientation of the fibers is good, so that the reinforcing performance can be sufficiently exhibited. In the present invention, a sheet-like molded product before pressure dehydration obtained after paper making of a slurry is defined as “green plate”.

The pressure plate can be dehydrated using a pressure dehydration apparatus such as a known press machine. Namaita pressurized dehydration conditions (rate of rise, holding pressure and the holding time, etc.), holding pressure 30 N / mm ² do not exceed 40N / mm ^2, preferably in the range of ^{35N / mm 2 ~40N / mm 2} .

The “apparent density” as used in the present specification means that the obtained material is dried to an absolutely dry state (a state dried at 105 ° C. until reaching a constant weight), and the mass (g) after drying is expressed as its volume (cm ^It can be calculated by the method of dividing by ³ ). The apparent density of the inorganic papermaking plate obtained by the production method of the present invention is 1.2 to 1.5 g / cm ³ , preferably 1.3 to 1.5 g / cm ³ .

  The curing and curing method is not particularly limited, and known means such as natural curing, wet curing, and cooling curing can be applied.

  The material thickness of the inorganic building materials currently on the market is 3 to 4 mm, which is a thin material, and the thickness below that is the cause of deflection due to its own weight, resulting in poor handling and handling during construction. Currently. However, the thin inorganic paper-making board produced by the production method of the present invention does not cause deflection due to its own weight, even at a thickness of 2 to 4 mm, has good handling properties during transportation and construction, and is easy to work with. Have advantages.

  Here, as the “deflection due to its own weight”, a plate having a long length of 910 mm and a length of 2575 mm (commonly called 8.5-size) is generally used in the longitudinal direction among the dimensions generally distributed in the building material market. The height difference between the support part and the end part in a state where the support part is supported by a single line at the center of the sword and is hung down by its own weight is measured. It is effective that the difference in height is 500 mm or less, preferably 400 mm or less. The thin inorganic papermaking plate produced by the production method of the present invention has a small amount of deflection due to its own weight, has good workability, and facilitates work during construction.

  Further, in the thin inorganic papermaking sheet obtained by the production method of the present invention, the maximum deflection in the bending pressure at the time of the bending test is a bending test perpendicular to the fiber direction defined in JIS A 1408 using a No. 4 test piece. , 15 mm or less, it can be a substitute characteristic for evaluating the rigidity. The term “maximum deflection” as used herein refers to the maximum amount of displacement obtained by combining the elastic region and the plastic region of the loaded part until the material breaks in a three-point bending test with a central single load.

Furthermore, the thin inorganic papermaking board obtained by the production method of the present invention is a bending test perpendicular to the fiber direction specified in JIS A 1408 using a No. 4 test piece (the dimensions of the test piece are 250 mm wide and 300 mm long). Yes, the span is 250 mm), and the bending strength in the fiber direction can be 25 N / mm ² or more. When this bending strength is less than 25 N / mm ² , when the bending due to its own weight occurs, it cannot withstand the bending stress applied to the thin inorganic papermaking plate, and cracks and cracks occur. However, by satisfying this bending strength, it can withstand bending stress due to deflection due to its own weight, and the workability is remarkably improved.

  A surface decorative layer may be provided on at least one surface of the thin inorganic papermaking plate produced by the method for producing a thin inorganic papermaking plate of the present invention to provide a thin surface inorganic coating paper. By providing the surface decorative layer, the design properties of the thin inorganic papermaking plate can be improved and the added value can be increased. In order to form the surface decorative layer, for example, paint, moisture-permeable paint, plaster paint, decorative paper, moisture-permeable decorative paper, decorative veneer (film), moisture-permeable decorative veneer (film) and the like can be used.

Here, a general urethane paint, an acrylic synthetic resin paint, or the like can be used as the paint.
Moreover, as a moisture-permeable coating material, what is disclosed by the said patent document 7, for example can be used. That is, it is a coating composition containing an alkoxysilane and a synthetic resin dispersion and having a structure having a moisture passage inside the dried coating.
Furthermore, as the plaster paint, a general-purpose product that is widely used at present for a textured outer wall can be used by mixing a slaked lime-based plaster material and a synthetic resin component.
The decorative paper, decorative veneer (film) and the like are not particularly limited as long as various types of coating are generally applied to the paper surface. In addition, when forming a surface decorative layer on the surface of a thin inorganic papermaking board using decorative paper, a decorative veneer (film), etc., it can adhere to the surface of a thin inorganic papermaking board using a conventional adhesive. . As such an adhesive, for example, an epoxy-based adhesive can be used.
Furthermore, as a moisture-permeable decorative paper, a moisture-permeable decorative veneer (film), etc., various coatings are generally applied to the surface of the paper, and the paper and the decorative layer have a large number of pores and are moisture-permeable. If it is a thing, it will not specifically limit. In addition, when forming a surface decorative layer on the surface of a thin inorganic papermaking board using a moisture-permeable decorative paper, a moisture-permeable decorative veneer (film), etc., the surface of the thin inorganic papermaking board using a moisture-permeable adhesive Can be glued to. As such a moisture-permeable adhesive, for example, aqueous vinyl urethane, melamine, vinyl acetate copolymer resin, or the like can be used.

  In addition, when a surface decorative layer is provided on a thin inorganic papermaking board, a sealer layer or a moisture permeable sealer layer is provided between the thin inorganic papermaking board and the surface decorative layer so that the adhesion between the thin inorganic papermaking board and the surface decorative layer is improved. Can be improved. As a sealer for forming the sealer layer, for example, a urethane sealer or the like can be used. Further, the sealer for forming the moisture permeable sealer layer is not particularly limited as long as it has moisture permeability. For example, a silica-modified acrylic copolymer resin, an acrylic resin emulsion, or the like can be used.

Example 1
Calcium silicate hydrate having an average particle size of 40 μm [tobermorite (slurry, solid content concentration = 10% by mass)] 20% by mass, ordinary Portland cement (manufactured by Taiheiyo Cement, specific surface area 3300 cm ² / g) 45% by mass; Silica fume 5 mass%; wood pulp (fiber length 3.5 mm, fiber diameter 30 μm, CSF 280 ml) 6 mass%; polyvinyl alcohol fiber (fiber length 4.0 mm, fiber diameter 27 μm) 2 mass%; calcium carbonate (inorganic filler) Water was added to and mixed with a composition having a composition of 22% by mass to obtain a slurry having a concentration of about 10% by mass, and this slurry was made by a round net type paper machine to obtain a green plate having a predetermined thickness. The obtained green plate was pressure dehydrated with a press at a pressure of 35 N / mm ² for 10 minutes, then cured at a temperature of 60 ° C. for 15 hours and cured to obtain a 3.2 mm thick inorganic papermaking plate. It was. The physical properties of the resulting inorganic paperboard are as follows:
Apparent density: 1.21 g / cm ³
Deflection by its own weight: 470mm in width 910mm, length 2572mm
Deflection due to pressure: 14.3 mm for No. 4 test piece
Bending strength in the fiber direction: 28 N / mm ²
In addition, the obtained inorganic papermaking plate was not easily bent in the construction, and the screwing to the ground was also good.

Example 2
Calcium silicate hydrate having an average particle size of 40 μm [tobermorite (slurry, solid content concentration = 10% by mass)] 20% by mass, ordinary Portland cement (manufactured by Taiheiyo Cement, specific surface area 3300 cm ² / g) 45% by mass; Silica fume 10 mass%; wood pulp (fiber length 3.5 mm, fiber diameter 30 μm, CSF 280 ml) 6 mass%; polyvinyl alcohol fiber (fiber length 4.0 mm, fiber diameter 27 μm) 2 mass%; calcium carbonate 17 mass% Water was added to and mixed with the mixture having a concentration of about 10% by mass to make a slurry having a concentration of about 10% by mass. The obtained green plate was pressure dehydrated with a press at a pressure of 38 N / mm ² for 10 minutes, then cured at a temperature of 60 ° C. for 15 hours, and cured to obtain an inorganic paper plate having a thickness of 3.3 mm. It was. The physical properties of the resulting inorganic paperboard are as follows:
Apparent density: 1.25 g / cm ³
Deflection due to its own weight: 430mm in width 910mm, length 2572mm
Deflection due to pressure: 14.0 mm for No. 4 test piece
Bending strength in the fiber direction: 29 N / mm ²
In addition, the obtained inorganic papermaking plate was not easily bent in the construction, and the screwing to the ground was also good.

Example 3
Calcium silicate hydrate having an average particle size of 40 μm [tobermorite (slurry, solid content = 10% by mass)] 15% by mass, ordinary Portland cement (manufactured by Taiheiyo Cement, specific surface area 3300 cm ² / g) 45% by mass; Silica fume 15% by mass; wood pulp (fiber length 3.5 mm, fiber diameter 30 μm, CSF 280 ml) 6% by mass; polyvinyl alcohol fiber (fiber length 4.0 mm, fiber diameter 27 μm) 2% by mass; calcium carbonate 17% by mass Water was added to and mixed with the mixture having a concentration of about 10% by mass to make a slurry having a concentration of about 10% by mass. The obtained green plate was dehydrated under pressure at a pressure of 32 N / mm ² for 10 minutes with a press machine, then cured at a temperature of 60 ° C. for 15 hours and cured to obtain a 3.1 mm thick inorganic papermaking plate. It was. The physical properties of the resulting inorganic paperboard are as follows:
Apparent density: 1.35 g / cm ³
Deflection due to its own weight: 395mm in width 910mm, length 2572mm
Deflection due to pressure: 12.8mm for No. 4 test piece
Bending strength in the fiber direction: 31 N / mm ²
In addition, the obtained inorganic papermaking plate was not easily bent in the construction, and the screwing to the ground was also good.

Comparative Example 1
Calcium silicate hydrate having an average particle size of 40 μm [tobermorite (slurry, solid content concentration = 10% by mass)] 20% by mass, ordinary Portland cement (manufactured by Taiheiyo Cement, specific surface area 3300 cm ² / g) 45% by mass; Silica fume 5 mass%; wood pulp (fiber length 3.5 mm, fiber diameter 30 μm, CSF 280 ml) 6 mass%; polyvinyl alcohol fiber (fiber length 4.0 mm, fiber diameter 27 μm) 2 mass%; calcium carbonate 22 mass% Water was added to and mixed with the mixture having a concentration of about 10% by mass to make a slurry having a concentration of about 10% by mass. The obtained green plate was pressure dehydrated at a pressure of 15 N / mm ² with a press machine for 10 minutes, then cured at a temperature of 60 ° C. for 15 hours and cured to obtain an inorganic paper plate having a thickness of 3.3 mm. It was. The physical properties of the resulting inorganic paperboard are as follows:
Apparent density: 1.15 g / cm ³
Deflection due to its own weight: 610mm in width 910mm, length 2572mm
Deflection due to pressure: 18.1 mm for No. 4 test piece
Bending strength in the fiber direction: 24 N / mm ²
In addition, the obtained inorganic papermaking board had a big deflection | deviation and was a thing which was hard to construct.

Comparative Example 2
Calcium silicate hydrate having an average particle size of 40 μm [tobermorite (slurry, solid content concentration = 10% by mass)] 20% by mass, ordinary Portland cement (manufactured by Taiheiyo Cement, specific surface area 3300 cm ² / g) 45% by mass; Silica fume 10 mass%; wood pulp (fiber length 3.5 mm, fiber diameter 30 μm, CSF 280 ml) 6 mass%; polyvinyl alcohol fiber (fiber length 4.0 mm, fiber diameter 27 μm) 2 mass%; calcium carbonate 17 mass% Water was added to and mixed with the mixture having a concentration of about 10% by mass to make a slurry having a concentration of about 10% by mass. The obtained green plate was pressure dehydrated with a press at 9 N / mm ² for 10 minutes, then cured at a temperature of 60 ° C. for 15 hours and cured to obtain a 3.2 mm thick inorganic papermaking plate. It was. The physical properties of the resulting inorganic paperboard are as follows:
Apparent density: 0.91 g / cm ³
Deflection due to its own weight: 730mm in width 910mm, length 2572mm
Deflection by pressurization: 24.8mm with No. 4 test piece
Bending strength in the fiber direction: 18 N / mm ²
In addition, the obtained inorganic papermaking board had a big deflection | deviation and was a thing which was hard to construct.

Comparative Example 3
Calcium silicate hydrate having an average particle size of 40 μm [tobermorite (slurry, solid content concentration = 10% by mass)] 20% by mass, ordinary Portland cement (manufactured by Taiheiyo Cement, specific surface area 3300 cm ² / g) 45% by mass; Silica fume 10 mass%; wood pulp (fiber length 3.5 mm, fiber diameter 30 μm, CSF 280 ml) 6 mass%; polyvinyl alcohol fiber (fiber length 4.0 mm, fiber diameter 27 μm) 2 mass%; calcium carbonate 17 mass% Water was added to and mixed with the mixture having a concentration of about 10% by mass to make a slurry having a concentration of about 10% by mass. The obtained green plate was pressure dehydrated with a press at a pressure of 20 N / mm ² for 10 minutes, then cured at a temperature of 60 ° C. for 15 hours and cured to obtain an inorganic paper plate having a thickness of 3.4 mm. It was. The physical properties of the resulting inorganic paperboard are as follows:
Apparent density: 1.05 g / cm ³
Deflection due to own weight: 910mm in width 910mm, length 2572mm
Deflection due to pressure: 20.3 mm for No. 4 test piece
Bending strength in the fiber direction: 20 N / mm ²
In addition, the obtained inorganic papermaking board had a big deflection | deviation and was a thing which was hard to construct.

Comparative Example 4
Calcium silicate hydrate having an average particle size of 40 μm [tobermorite (slurry, solid content concentration = 10% by mass)] 20% by mass, ordinary Portland cement (manufactured by Taiheiyo Cement, specific surface area 3300 cm ² / g) 45% by mass; Silica fume 10 mass%; wood pulp (fiber length 3.5 mm, fiber diameter 30 μm, CSF 280 ml) 6 mass%; polyvinyl alcohol fiber (fiber length 4.0 mm, fiber diameter 27 μm) 2 mass%; calcium carbonate 17 mass% Water was added to and mixed with the mixture having a concentration of about 10% by mass to make a slurry having a concentration of about 10% by mass. When the obtained green plate was pressure dehydrated with a press at a pressure of 48 N / mm ² , cracks occurred and a good test specimen could not be produced.

Comparative Example 5
Calcium silicate hydrate having an average particle size of 40 μm [tobermorite (slurry, solid content concentration = 10% by mass)] 20% by mass, ordinary Portland cement (manufactured by Taiheiyo Cement, specific surface area 3300 cm ² / g) 45% by mass; Silica fume 25 mass%; wood pulp (fiber length 3.5 mm, fiber diameter 30 μm, CSF 280 ml) 6 mass%; polyvinyl alcohol fiber (fiber length 4.0 mm, fiber diameter 27 μm) 2 mass%; calcium carbonate 2 mass% Water was added to and mixed with the mixture having a concentration of about 10% by mass to make a slurry having a concentration of about 10% by mass. When the obtained green plate was pressure dehydrated with a press at a pressure of 35 N / mm ² , cracks occurred and a good specimen could not be produced.

  The thin inorganic papermaking board obtained by the production method of the present invention can be suitably used as a building material or the like.

Claims (2)

20 to 60% by mass of hydrated raw material for matrix formation; 3 to 11% by mass of natural fibers having a freeness within the range of 150 to 450 ml in Canadian standard freeness and / or fiber length of 6.0 to 0.2 mm, fiber diameter 0.5 to 5% by mass of inorganic fiber and / or synthetic fiber (excluding asbestos) in the range of 20 to 50 μm, provided that the total amount of natural fiber and inorganic fiber and / or synthetic fiber is 3.5 to 12% by mass; 10-50% by mass of calcium silicate hydrate having an average particle diameter of 30 μm to 100 μm obtained by hydrothermal synthesis of a calcareous raw material and a silicic raw material in advance; 1-50% by mass of an inorganic filler; and A slurry containing 1 to 20% by mass of silica fume is wet-mixed to obtain a slurry, and the resulting slurry is made into paper to obtain a green plate, and the green plate is maintained at a holding pressure of 30 N / After pressurizing圧脱water until m ² than 40N / mm ^2, a thickness of 2~4mm by curing curing, thin inorganic, characterized in that to obtain a cured product of an apparent density 1.2~1.5g / cm ³ A manufacturing method of papermaking board. Deflection due to its own weight when it is supported at the central portion in the longitudinal direction of a thin inorganic papermaking sheet having a width of 910 mm and a length of 2575 mm is 500 mm or less due to the difference between the central portion and the edge portion, JIS A The maximum deflection in the fiber direction according to a three-point bending test with a central one-line support using No. 4 test piece of 1408 regulation is 15 mm or less, and the bending strength in the fiber direction is 25 N / mm ² or more. Manufacturing method of thin inorganic papermaking board.