JP2889529B2 - Manufacturing method of inorganic plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an inorganic plate mainly used for construction.

[0002]

2. Description of the Related Art A cement-based inorganic plate is formed by mixing a hydraulic material mainly composed of cement with aggregates and fibers as required, and then forming the hydraulic material by wet papermaking or the like. It is produced by making a sheet and autoclaving the green sheet. By autoclaving the green sheet in this way, a high-quality inorganic plate having excellent dimensional stability and strength can be obtained.

However, when the autoclave curing is performed in this way, efflorescence tends to occur, the surface of the product becomes uneven, and the adhesion of the coating film applied to the surface of the product deteriorates, so that peeling easily occurs. Problem. Efflorescence is generated by free lime generated by the hydrolysis of cement eluted into water and comes out to the surface. This sealer is applied to a surface to prevent free lime from eluted into water during autoclave curing, thereby preventing the occurrence of efflorescence.

[0004]

However, when the sealer made of the aqueous resin dispersion stays only on the surface of the green sheet, the generation of efflorescence from the inside of the green sheet cannot be suppressed, and the sealer cannot be used. If you seep into the green sheet,
The generation of efflorescence on the surface of the green sheet cannot be suppressed, and it has been difficult to reliably prevent the generation of efflorescence.

The present invention has been made in view of the above points, and has as its object to provide a method of manufacturing an inorganic plate capable of reliably preventing the occurrence of efflorescence.

[0006]

According to the present invention, a green sheet is formed by molding a hydraulic material containing cement as a main component, and the green sheet is subjected to autoclave curing to obtain a product specific gravity of 0.95 to 1.3. In producing the inorganic plate of (1), an aqueous resin dispersion (a) having an average particle size of the dispersoid of 0.06 to 0.09 μm and an average particle size of the dispersoid of 0.10
To 0.20 μm of the aqueous resin dispersion (b), (solid content of aqueous resin dispersion (a)) / (solid content of aqueous resin dispersion (a) + solid content of aqueous resin dispersion (b) ) =
It is characterized in that a sealer prepared by blending so as to have a weight ratio of 0.6 to 0.8 is applied to the surface of a green sheet and then autoclaved.

[0007]

Embodiments of the present invention will be described below. Hydraulic materials are usually prepared as a slurry by mainly containing cement such as Portland cement or fly ash cement, blending aggregates and fibers as necessary, and mixing these with water. . The mixing ratio of the solid content in the hydraulic material is 70 ± 1 for cement.
It is preferable to adjust so that 0% by weight, 20 ± 5% by weight of aggregate and 10 ± 5% by weight of fiber. A green sheet can be formed by subjecting the hydraulic material to wet papermaking or the like.

Prior to autoclaving the green sheet thus formed, a sealer is applied to the surface of the green sheet. In the present invention, as the sealer, an aqueous resin dispersion (a) having an average particle size of the dispersoid of 0.06 to 0.09 μm, and an average particle size of the dispersoid of 0.10 to 0.09 μm are used.
０．２0.20 μm of the aqueous resin dispersion (b), and the mixing ratio of the aqueous resin dispersion (a) and the aqueous resin dispersion (b) is adjusted to the ratio of the aqueous resin dispersion (a). The solid content is Wa parts by weight, and the solid content of the aqueous resin dispersion (b) is Wb.
Assuming parts by weight, Wa / (Wa + Wb) = 0.6 to 0.
The sealer is prepared so as to be set at 8. The MFT (minimum) of these resin aqueous dispersions
um film forming temperatu
re: minimum film formation temperature) is 55% for the aqueous resin dispersion (a).
The aqueous resin dispersion (b) is preferably in the range of 45 to 65 ° C.

As the aqueous resin dispersions (a) and (b), there can be used aqueous emulsions in which the dispersoid is resin colloid particles and the dispersion medium is water, such as an aqueous acrylic resin emulsion. It is preferable that the sealer containing the aqueous resin dispersions (a) and (b) is prepared so that the concentration of the dispersoid is in the range of 40 to 60% by weight. The amount of the sealer applied to the surface of the green sheet is preferably in the range of 5 to 12 g / scale ² . The sealer may be applied to at least the surface of the green sheet that is to be on the front side.

After applying the sealer to the green sheet as described above, the sealer is dried by heating at a temperature of about 100 to 160 ° C. for about 2 minutes to evaporate the moisture of the sealer.・
By curing the cement by autoclaving under high pressure, an inorganic plate can be obtained.
The conditions of the autoclave curing are not particularly limited, but are preferably set to a temperature of 160 to 170 ° C. and a time of about 3 to 6 hours. In the present invention, by adjusting the composition of the hydraulic material and the molding density of the green sheet,
An inorganic plate having a product specific gravity of 0.95 to 1.3 can be obtained. When the specific gravity of the product is less than 0.95, the green sheet has large internal voids, so that the applied sealer penetrates too much, the sealer hardly stays on the surface layer and the surface, and the efflorescence is easily generated, and the strength is increased. In addition, there is a problem that the plate thickness must be increased in order to obtain. Conversely, if the product specific gravity exceeds 1.3,
The green sheet is too dense, the applied sealer is difficult to penetrate, and efflorescence tends to occur,
In addition, the inorganic plate may be hardened, causing cracking at the time of nailing and making cutting difficult. Therefore, in the present invention, an inorganic plate having a specific gravity of 0.95 to 1.3 is obtained.

[0011] Further, as described above, in the inorganic plate obtained by autoclaving the green sheet, a sealer is applied to the green sheet, so that free lime is prevented from being eluted into water and coming out of the surface. Thus, it is possible to prevent the occurrence of efflorescence. In addition, the sealer has an average particle size of the dispersoid of 0.06 to 0.0.
Since the resin aqueous dispersion (a) as small as 9 μm and the resin aqueous dispersion (b) as large as 0.10 to 0.20 μm in average particle diameter of the dispersoid are prepared, the dispersoid is prepared. The resin aqueous dispersion (a) having a small average particle diameter of the resin permeates into the green sheet, and the resin aqueous dispersion (b) having a large average particle diameter of the dispersoid stays on the surface of the green sheet. A continuous resin film can be made from the surface to the inside, which can suppress both the generation of efflorescence from the inside of the green sheet and the generation of efflorescence on the surface of the green sheet. As a result, it is possible to reliably prevent the occurrence of eflorescence. Therefore, the surface of the inorganic plate does not become uneven, and the adhesion to the coating film applied to the surface of the inorganic plate is improved. In addition, the sealer in which the two types of resin aqueous dispersions (a) and (b) are mixed penetrates uniformly from the surface to the inside even at a portion where the penetration of the aqueous resin dispersion is different, such as a joint portion of the inorganic plate. It is possible to reliably prevent the occurrence of efflorescence.

If the average particle size of the dispersoid of the aqueous resin dispersion (a) exceeds 0.09 μm, it is difficult to allow the dispersoid particles of the aqueous resin dispersion (a) to penetrate into the green sheet. On the other hand, if the average particle diameter of the dispersoid of the aqueous resin dispersion (a) is less than 0.06 μm, the dispersoid penetrates too deeply into the green sheet, and the dispersoid is diffused to reduce the effect of preventing efflorescence. It may decrease. Further, the average particle size of the dispersoid of the aqueous resin dispersion (b) is 0.1%.
When it is less than 0 μm, it is difficult to keep the dispersoid particles of the aqueous resin dispersion (b) on the surface of the green sheet, and conversely, the average particle diameter of the dispersoid of the aqueous resin dispersion (b) is 0.1 μm. If it exceeds 20 μm, the space between the dispersoid particles becomes large and the surface cannot be covered cleanly, and efflorescence may be generated from this gap. For this,
The average particle size of the dispersoids of the aqueous resin dispersions (a) and (b) is set in the above range.

As described above, the mixing ratio of the aqueous resin dispersion (a) and the aqueous resin dispersion (b) of the sealer is such that the solid content of the aqueous resin dispersion (a) is Assuming that the solid content of the liquid (b) is Wb parts by weight, Wa / (Wa
+ Wb) = 0.6 to 0.8, but this is because the mixing ratio of the aqueous resin dispersion (a) is 0.6
If the ratio is less than the above, the permeability into the inside of the green sheet decreases, and the effect of preventing the occurrence of efflorescence from inside decreases, and conversely, the mixing ratio of the aqueous resin dispersion (a) becomes 0.8. If it exceeds, the permeation into the inside of the green sheet becomes too large and the amount of the green sheet remaining on the surface decreases, and the effect of preventing the occurrence of efflorescence on the surface decreases.

[0014]

Next, the present invention will be described specifically with reference to examples. (Example) 40 parts by weight of cement, 40 parts by weight of fly ash, 10 parts by weight of silica stone, 10 parts by weight of pulp, 3 parts by weight of mica, and 10 parts by weight of a scrap crushed product of a cement board are mixed and mixed with water. Thus, a cement slurry having a solid content of 13% by weight was prepared. Then, the cement-based slurry was formed into a paper having a water content of 35% by weight and a thickness of 1%.
A 5 mm green sheet was produced.

On the other hand, as an aqueous resin dispersion (a), "Acronal YJ1110D" manufactured by Mitsubishi Chemical BASF Co., Ltd.
(Acryl styrene resin aqueous emulsion, dispersoid average particle size 0.07 μm, MFT 65 ° C.) was used as an aqueous resin dispersion (b), “Acronal YJ1120D” (manufactured by Mitsubishi Chemical BASF Co., Ltd.) (acryl styrene resin aqueous emulsion, dispersoid average particle 0.14μm diameter, MFT 57 ° C)
And the solid content of the aqueous resin dispersion (a) is 70
The aqueous resin dispersions (a) and (b) were mixed to prepare a sealer so that the solid content of the aqueous resin dispersion (b) was 30% by weight (Wa / (Wa + Wb) = 0.7). ).

Then, the sealer was applied on the surface of the green sheet at an application amount of 10 g / scale ² and dried by heating at 130 ° C. for 2 minutes. Next, 165 green sheets
An autoclave curing was performed under saturated steam of 8 to 9 kg / cm ² at 4.5 ° C. for 4.5 hours to obtain an inorganic plate having a product specific gravity of 1.1 and a thickness of 15 mm. (Comparative Example 1) Mitsubishi Chemical BA as an aqueous resin dispersion (a)
Using “Acronal YJ1850D” (aqueous acrylic styrene resin emulsion, average particle size of dispersoid 0.05 μm, MFT 50 ° C.) manufactured by SF Co., Ltd., and using the same aqueous resin dispersion (b) as in the example, The liquids (a) and (b) were mixed at the same mixing ratio as in the example to prepare a sealer (Wa / (Wa + Wb) = 0.
7). Using this sealer, an inorganic plate was obtained in the same manner as in the other examples.

Comparative Example 2 An inorganic plate was obtained in the same manner as in Example except that the same aqueous resin dispersion (b) as in Example was used alone as a sealer. Comparative Example 3 An inorganic plate was obtained in the same manner as in Example except that the same resin aqueous dispersion (a) as in Example was used alone as a sealer.

(Comparative Example 4) The same aqueous resin dispersion (a) as in the example was used, and as the resin aqueous dispersion (b), “Acronal YJ1660D” (aqueous acrylic styrene resin emulsion, manufactured by Mitsubishi Chemical BASF) was used. Using a dispersoid having an average particle size of 0.3 μm and an MFT of 8 ° C., the aqueous resin dispersions (a) and (b) were mixed at the same mixing ratio as in the example to prepare a sealer (Wa / (Wa + W)
b) = 0.7). Using this sealer, an inorganic plate was obtained in the same manner as in the other examples.

Comparative Example 5 Resin aqueous dispersion (a),
The same aqueous resin dispersion (a) as in Example was used as (b) such that the solid content of the aqueous resin dispersion (a) was 40% by weight and the solid content of the aqueous resin dispersion (b) was 60% by weight. a) and (b) were mixed to prepare a sealer (Wa /
(Wa + Wb) = 0.4). Using this sealer, an inorganic plate was obtained in the same manner as in the other examples.

Comparative Example 6 Resin aqueous dispersion (a),
The same aqueous resin dispersion (a) as in Example was used as (b) so that the solid content of the aqueous resin dispersion (a) was 90% by weight and the solid content of the aqueous resin dispersion (b) was 10% by weight. a) and (b) were mixed to prepare a sealer (Wa /
(Wa + Wb) = 0.9). Using this sealer, an inorganic plate was obtained in the same manner as in the other examples.

With respect to the inorganic plates obtained in the above Examples and Comparative Examples 1 to 6, the presence or absence of efflorescence was visually inspected. Indicates "△", and indicates that the occurrence of eflorescence is large "x".
Was evaluated. Table 1 shows the results.

[0022]

[Table 1]

As can be seen from Table 1, no efflorescence from the surface or efflorescence from inside was observed in the embodiment. On the other hand, in Comparative Example 1 using the aqueous resin dispersion (a) having an average particle size that is too small, efflorescence from the inside is liable to occur, and Comparative Example using the aqueous resin dispersion (b) having an average particle size that is too large. In No. 4, efflorescence on the surface was liable to occur. In Comparative Example 2 using only the aqueous resin dispersion (b) and Comparative Example 5 in which the amount of the aqueous resin dispersion (b) was too large, efflorescence from the inside tended to occur. Comparative Example 3 using only (a) and the aqueous resin dispersion (a)
In Comparative Example 6 in which the amount of was too large, efflorescence on the surface tended to occur.

[0024]

As described above, according to the present invention, a green sheet is formed by molding a hydraulic material containing cement as a main component, and the green sheet is subjected to autoclave curing to obtain a product specific gravity of 0.95 to 1.3. In producing the inorganic plate of (1), an aqueous resin dispersion (a) having an average particle size of the dispersoid of 0.06 to 0.09 μm and an average particle size of the dispersoid of 0.10
To 0.20 μm of the aqueous resin dispersion (b), (solid content of aqueous resin dispersion (a)) / (solid content of aqueous resin dispersion (a) + solid content of aqueous resin dispersion (b) ) =
Since the sealer prepared by blending so as to have a weight ratio of 0.6 to 0.8 was applied to the surface of the green sheet and then autoclaved, the average particle diameter of the dispersoid was 0.06 to 0.8.
The aqueous resin dispersion (a) as small as 0.09 μm penetrates well into the green sheet, and the aqueous resin dispersion (b) with an average particle size of the dispersoid as large as 0.10 to 0.20 μm is green. It stays on the surface of the sheet and allows the sealer to uniformly penetrate from the surface to the inside.Efforescence from the inside of the green sheet and efflorescence on the surface of the green sheet are both generated. It is possible to suppress the occurrence of the eflorescence, and to surely prevent the occurrence of the eflorescence.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C04B 40/00-40/06

Claims (1)

(57) [Claims] 1. A green sheet is formed by molding a hydraulic material containing cement as a main component, and the green sheet is subjected to autoclave curing to produce an inorganic plate having a specific gravity of 0.95 to 1.3. An aqueous resin dispersion (a) having an average particle size of the dispersoid of 0.06 to 0.09 μm and an aqueous resin dispersion (b) having an average particle size of the dispersoid of 0.10 to 0.20 μm are represented by the following formula: Solid content of aqueous resin dispersion (a)) / (solid content of aqueous resin dispersion (a) + solid content of aqueous resin dispersion (b)) =
A method for producing an inorganic plate, comprising applying a sealer prepared by blending so as to have a weight ratio of 0.6 to 0.8 on the surface of a green sheet, followed by autoclaving.