JP2006069806A - Inorganic board and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inorganic board largely improved in dimensional stability and anti-freezing and melting properties. <P>SOLUTION: When the inorganic board is manufactured by forming a mat in paper making manner by dispersing in water a raw material mixture which contains a cement-based inorganic material, a siliceous matter-containing material, a wooden reinforcing material and a mica in water, and pressing the mat formed like mentioned above and curing it at a temperature of 150°C or higher in an autoclave; the hardening reaction of the inorganic board is promoted by setting the mass ratio of the cement-based inorganic material to the siliceous matter-containing material in the range of 35:65 to 45:55, and thereby, the dimensional stability is further improved and furthermore, the anti-freezing and melting properties are made better. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inorganic plate containing mica and a method for producing the same.

  Conventionally, asbestos has been used as a reinforcing material for inorganic board, but environmental pollution has become a problem due to the scattering of fine asbestos powder, and wood reinforcing materials such as wood fragments and wood fibers have been used as a reinforcing material to replace asbestos. It was.

However, an inorganic board reinforced with a wooden reinforcing material is inferior in dimensional stability, stretches and contracts due to moisture absorption drying, tends to cause warping, and in the worst case, has a drawback of causing cracks.
In order to remedy such drawbacks, it has been proposed to add mica to a mixture of wood reinforcement and cement. Mica has a high elastic modulus, and by adding mica, the dimensional stability, cutting ability, nailability and the like of the inorganic plate are greatly improved. (For example, see Patent Documents 1, 2, and 3).

JP 2002-166406 A JP-A-6-329457 Japanese Patent Laid-Open No. 5-124845

As described above, by adding mica, the dimensional stability of the inorganic board is improved, but when added in a large amount, it becomes difficult to uniformly mix the raw materials, and it becomes impossible to obtain an inorganic board with stable quality, and There is a problem that the raw material cost is also increased.
Accordingly, an object of the present invention is to provide an inorganic plate that is excellent in dimensional stability and freeze-thaw resistance even when the amount of mica added is limited.

As a means for solving the above-mentioned conventional problems, the present invention comprises a cured product of a raw material mixture containing a cement-based inorganic material, a siliceous material-containing material, a wood reinforcing material, and mica, and the cement-based inorganic material And the siliceous-containing material are provided with an inorganic plate whose mass ratio is set in a range of 35:65 to 45:55. In addition, a cement-based inorganic material, a siliceous-containing material, Then, a raw material mixture containing a wood reinforcing material and mica is dispersed in water to prepare a raw material slurry, and the raw material slurry is made to form a paper making mat, and the paper making mat is pressed at a temperature of 150 ° C. or higher. A method for producing a wood cement board for curing an autoclave, wherein the mass ratio of the cement-based inorganic material and the siliceous material is set in a range of 35:65 to 45:55 It is intended to provide.
The average particle diameter of mica used in the raw material mixture is 200 to 700 μm, the aspect ratio is 60 to 100, and the mica content is preferably set in the range of 2 to 7% by mass. The CSF of the wood reinforcing material is 500 ml or less, and the content of the wood reinforcing material is preferably set to 5 to 10% by mass.

  In the present invention, by setting the mass ratio of the cement-based inorganic material to the siliceous material-containing material in the range of 35:65 to 45:55, the curing reaction of the inorganic plate is smoothly promoted. Even if the addition amount is reduced and uniform mixing of raw materials is facilitated, it is possible to provide an inorganic plate with greatly improved dimensional stability and good freeze-thaw resistance.

The present invention is described in detail below.
[Wood reinforcement]
Examples of the wood reinforcing material used in the present invention include wood powder, wood wool, wood fragments, wood fiber, wood pulp, wood fiber bundles, strands, conifers, hardwoods, pulp made from waste paper, etc. May be mixed in two or more, and the wood reinforcing material may be mixed with a material mainly composed of lignocellulose such as bamboo fiber, hemp fiber, bacus, rice bran, rice straw and the like. Preferred wood reinforcing materials include C.I. S. F (Canadian Standard Freeness) 500 ml or less of softwood unbleached pulp (NUKP) or softwood bleached pulp (NBKP).

[Cement-based inorganic materials]
Examples of the cement-based inorganic material used in the present invention include cements such as Portland cement, blast furnace slag cement, silica cement, fly ash cement, and alumina cement.

[Silica-containing material]
In the present invention, a siliceous material is used in combination with the cement-based inorganic material to accelerate the curing reaction of the cement-based inorganic material. Examples of the siliceous material include silica powder, silica sand, silica stone powder, water glass, silica fume, shirasu balloon, perlite, diatomaceous earth, dolomite and the like.

[Mica]
As the mica used in the present invention, flakes having an average particle size of 200 to 700 μm and an aspect ratio of 60 to 100 are desirable. Mica is a highly elastic body that usually has a layered structure, does not absorb moisture, and has rigidity, and can greatly improve the dimensional stability of the wood cement board.

[Other ingredients]
As raw materials for the inorganic plate of the present invention, as components other than the above, inorganic fibers such as sepiolite, wollastonite, glass fiber, whisker, calcium chloride, magnesium chloride, potassium sulfate, calcium sulfate, magnesium sulfate, aluminum sulfate, aluminum Cement hardening accelerators such as sodium oxide, potassium aluminate, calcium formate, calcium acetate, calcium acrylate, water glass, mineral powders such as vermiculite, bentonite, waterproofing agents such as wax, wax, paraffin, silicon, surfactants, etc. Water repellents, expandable thermoplastic beads, plastic foams and the like may be added. In addition, these illustrations do not limit the present invention.

[Composition of inorganic board]
In the raw material mixture of the inorganic board of the present invention, the mass ratio of the cement-based inorganic material to the siliceous material-containing material for promoting the curing reaction of the cement-based inorganic material is in the range of 35:65 to 45:55. In the raw material mixture, the wood reinforcing material is 5 to 10% by weight, the cement-based inorganic material is 25 to 45% by weight, the siliceous material is 45 to 65% by weight, and the mica is 2 to 7% by weight (each solid content). Preferably included. If the mica content is less than 2% by mass, the dimensional stability of the resulting inorganic plate cannot be sufficiently improved. If the mica content exceeds 7% by mass, it is difficult to uniformly mix the raw materials. Thus, it is difficult to obtain an inorganic plate with stable quality, and the cost is increased.

[Manufacture of inorganic board]
The inorganic board of the present invention is manufactured by a papermaking method.
In the papermaking method, a raw material slurry prepared by dispersing and kneading a raw material mixture containing the above cement-based inorganic material, siliceous material-containing material, wood reinforcing material, mica, etc. in water is flow-on type, long net type, After the papermaking mat is manufactured by a known method such as the Hatschek type, it is preferably pressed at a pressure of 20 MPa or higher, and preferably autoclaved at a temperature of 150 ° C. or higher and a pressure of 0.4 MPa or higher.
In this case, the solid content concentration of the slurry is usually 5 to 15% by weight, and the papermaking mat is usually produced by winding a papermaking sheet formed by papermaking on a making roll and laminating 6 to 15 layers.

  In the manufacturing process of the inorganic board, when a raw material slurry is made and a paper making mat is formed, if mica having an aspect ratio of 60 to 100 or more is used, the mica is easily oriented in the paper making direction. And when the mica is subjected to autoclave curing at a temperature of 150 ° C. or higher, preferably under a pressure of 0.4 MPa or higher, in the presence of a large amount of water, siliceous components and alumina components are eluted from the mica surface, Therefore, the mica surface becomes rough. Further, when the mica has a large surface area with a particle size of 200 to 700 μm or more, the overlapping area between mica becomes large.

  As described above, in the autoclave curing at a temperature of 150 ° C. or more in the presence of a large amount of water, the surface of the mica is rough, so that calcium eluted from the cement-based inorganic material in the presence of a large amount of water at the overlapping portion. Calcium content is easy to enter between the overlapping portions of the mica, and this calcium content reacts with the silicate component and some alumina components eluted from the mica surface to stabilize the calcium silicate between the overlapping portions of the mica. A reaction cured product is generated, the reaction cured product adheres to each other, and the mica is overlapped with each other through the reaction cured product in synergy with the large overlapping area of the mica as described above, that is, the adhesion area. The

As described above, it is desirable that the mica content in the raw material mixture is within a range not exceeding 7% by mass from the viewpoint of the raw material mixing workability, but even in such a small addition range, the effect of improving the dimensional stability of mica In the present invention, the mass ratio of the cement-based inorganic material (C) and the siliceous material (S) is set in the range of 35:65 to 45:55.
Within this range, the curing reaction of the inorganic plate proceeds smoothly, the amount of unreacted C component and unreacted S component is drastically reduced, and a large amount of card house-like tobermorite crystals are formed, resulting in a significant effect of improving the dimensional stability of mica. The width is improved and the freeze-thaw resistance of the plate is also improved. As a result, the inorganic board of the present invention obtains large mechanical strength, greatly improved dimensional stability and freeze-thaw resistance. In the case of C / S <35/65, the amount of unreacted S component increases and the amount of tobermorite crystals produced decreases, and the freeze-thaw resistance becomes insufficient. In the case of C / S> 45/55, silicic acid The amount of cement hydrate, which is not a cured product due to the calcium reaction, increases, and as a result, the plate becomes brittle and crack resistance decreases.

  Further, since the mica surface is rough as described above, even if the mica is present on the surface of the wood cement board, when the surface of the inorganic board is coated, the adhesion with the paint is not good. It is no longer inhibited by the mica.

  In order to apply the surface of the inorganic board of the present invention thus produced, for example, an organic solvent solution type acrylic resin paint, an aqueous emulsion type acrylic resin paint, a urethane resin paint, a silicon resin paint, etc. An undercoat paint is applied, and if desired, an intermediate coat paint similar to the above-mentioned undercoat paint is applied thereon, for example, an organic solvent solution type acrylic resin paint, an aqueous emulsion type acrylic resin system. A top coat such as paint or organic solvent solution type silicon acrylic resin paint is applied.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited to these examples.

[Examples 1-5, Comparative Examples 1-5]
A raw material mixture having the composition shown in Table 1 was prepared as a raw material for the inorganic plate.

  The raw material mixture is dispersed in water to prepare a raw material slurry having a solid content of 10% by weight, the raw material slurry is made on a felt to form a paper making mat, the paper making mat is pressed at a pressure of 23 MPa, and a temperature of 50 ° C. Was subjected to primary curing for 24 hours, and further autoclave curing at 170 ° C. and 0.7 MPa for 7 hours to prepare an inorganic plate sample.

Each of the above-mentioned various inorganic plate samples was subjected to tests such as absolute dry specific gravity, bending strength, water absorption elongation rate, moisture release shrinkage rate, microcrack test, and freeze-thaw resistance.
Table 2 shows the results of the above tests.

  As is apparent from Table 2, in Examples 1 to 5, the C / S mass ratio is set in the range of 35:65 to 45:55, and the strength, dimensional stability, and freeze-thaw resistance are all the same. Although satisfactory results were obtained, in Comparative Examples 1 and 2, the dimensional stability is not sufficient and cracks are likely to occur. Further, even if mica is added, it is 2% by mass or less, and in Comparative Example 3 where C / S = 6/4 (excess C component), the dimensional stability is slightly inferior, cracks are likely to occur, and freezing and thawing resistance is further increased. In Comparative Example 4 where C / S = 6/4 (excess C component) even if 7% by mass of mica is added, the dimensional stability is good, but cracks are likely to occur, and Also inferior in freeze-thaw resistance. Furthermore, in Comparative Example 5 containing excessive mica (12% by mass), the plate structure becomes non-uniform and the strength decreases.

  The inorganic board of the present invention is excellent in dimensional stability and freeze-thaw resistance, and is extremely useful for building boards such as outer wall materials.

Claims (6)

  It consists of the hardened | cured material of the raw material mixture containing a cement-type inorganic material, a siliceous-containing material, a wooden reinforcement material, and mica, The mass ratio of this cement-type inorganic material and this siliceous-containing material is 35:65. It is set to the range of -45: 55, The inorganic board characterized by the above-mentioned.   2. The mica used in the raw material mixture has an average particle size of 200 to 700 μm, an aspect ratio of 60 to 100, and a content of the mica of 2 to 7% by mass. Inorganic board.   The inorganic board according to claim 1 or 2, wherein a CSF of the wood reinforcing material used in the raw material mixture is 500 ml or less, and a content of the wood reinforcing material is 5 to 10% by mass.   A raw material mixture containing a cement-based inorganic material, a siliceous material, a wood reinforcing material, and mica is dispersed in water to prepare a raw material slurry, and the raw material slurry is made to form a paper making mat, A method for producing an inorganic board in which a paper mat is pressed and cured by autoclaving at a temperature of 150 ° C. or more, wherein the mass ratio of the cement-based inorganic material and the siliceous material is set in the range of 35:65 to 45:55. The manufacturing method of the inorganic board characterized by doing.   The inorganic plate according to claim 4, wherein in the raw material mixture, the average particle diameter of mica is 200 to 700 µm, the aspect ratio is 60 to 100, and the content of the mica is set in the range of 2 to 7% by mass. Manufacturing method.   The method for producing an inorganic board according to claim 4 or 5, wherein in the raw material mixture, the CSF of the wood reinforcing material is 500 ml or less, and the content of the wood reinforcing material is set to 5 to 10% by mass.