JPH082526B2 - Method for producing cement-based inorganic board - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a cement-based inorganic board used as a building material or the like.

[Background Art] When a cement-based inorganic board is used as a building material such as a roofing material, it is necessary to impart water permeation resistance to the surface in order to enhance the waterproof performance, or to enhance the planar adhesiveness of the surface. For this purpose, conventionally, a colored cement is applied to the surface of the cement-based inorganic plate to provide a dense color ply layer,
This dense color ply layer is used to prevent water permeation and enhance the planar adhesiveness.

However, in this case, the cement-based inorganic plate has a two-layer structure of a base material layer and a color ply layer, which may cause a problem of delamination, and the color ply layer of the colored cement has high alkalinity and efflorescence. It is likely to occur, and there is a possibility that a poor appearance may occur.

[Object of the Invention] The present invention has been made in view of the above points, and forms a dense surface layer for improving waterproof performance and planar adhesion without problems such as efflorescence delamination. It is an object of the present invention to provide a method for producing a cement-based inorganic board capable of producing a cement-based inorganic board.

DISCLOSURE OF THE INVENTION The method for producing a cement-based inorganic plate according to the present invention, however, is a cement-based method for forming the surface layer 4 portion of the paper-making sheet 3 when the cement-based slurry 1 is made into a paper-making sheet 3. It is characterized in that microsilica 5 is dispersed and mixed in the slurry 1 to fill the surface layer 4 of the papermaking sheet 1 with 10g / m ² or more and less than 100g / m ² of microsilica 5 and the papermaking sheet 11 is cured by curing. The present invention will be described in detail below.

Cement-based slurry 1 is prepared by dispersing cement and other hydraulic substances such as gypsum, reinforcing fibers and fillers in water, and by making this cement-based slurry 1 into paper by, for example, a Fourdrinier paper machine. The paper sheet 3 can be prepared. That is, as shown in FIG. 1, a slurry tank 8 to which the cement-based slurry 1 is supplied.
A part of the endless felt 2 is made to face the bottom of the slurry tank 8, and a suction box 9 connected to a vacuum pump is provided on the back side of the felt 2 at the bottom of the slurry tank 8. Then, when the felt 2 is driven to run while operating the vacuum pump of the suction box 9, the cement slurry 1 is filtered by the suction force of the suction box 9 at the bottom of the slurry tank 8 as the water passes through the felt 2. The solid content in the cement-based slurry 1 remains on the surface of the felt 2, and the papermaking sheet 3 made of the solid content of the cement-based slurry 1 is made on the surface of the felt 2. Here, while the felt 2 travels in the slurry tank 8, the solid content of the cement-based slurry 1 is gradually deposited on the surface of the felt 2 and grows into the paper sheet 3, and thus the surface layer of the paper sheet 3 is formed. 4 is a slurry tank 8
Among them, it is formed by the cement-based slurry 1 in the end of the felt 2 on the outlet side.

In the present invention, the microsilica 5 is sprinkled and dispersed from the nozzle 12 at the tip of the pipe of the cement-based slurry 1 at the end of the felt 2 of the slurry tank 8 on the outlet side. The microsilica 5 is filled in the surface layer 4 when the surface layer 4 is formed. At this time, it is preferable that the slurry tank 8 is provided with a weir 10 so that the microsilica 5 is not dispersed in other parts in the slurry tank 8. The paper sheet 3 thus formed on the surface of the felt 2 is dehydrated by the suction box 11 in the dehydration step. Further, after the paper sheet 3 is taken out from the felt 2, it is finished as a cement-based inorganic board A such as a building material through known steps such as press molding, curing and drying.

Here, the micro-silica 5 is an extremely small silica powder having a particle size of about 1/100 μ to 5 μ, and therefore, in the surface layer 4 of the papermaking sheet 3, micro voids are present in the voids between the cement matrix, the reinforcing fibers and the filler. The silica 5 is filled to fill the voids. Therefore, the surface layer 4 of the cement-based inorganic plate A becomes a dense layer due to the sealer effect and the surface reinforcing effect of the microsilica 5, as shown in FIG. Therefore, the dense surface layer 4 can improve the water permeation resistance of the cement-based inorganic board A and the planar adhesive strength. The surface layer 4 is formed by being filled with the micro silica 5 and is not a layer independent from the base material portion of the cement-based inorganic board A, but is a case where a color ply layer is formed by a conventional colored cement. There is no problem of delamination or efflorescence. In particular, the microsilica 5 has the property of reacting with an alkali and hardening very easily.
The peeling can be effectively prevented, and the free alkali near the surface of the cement-based inorganic plate A can be fixed to effectively prevent the occurrence of efflorescence.
The amount of the microsilica 5 to be blended is not particularly limited, but it is desirable that the amount of the microsilica 5 is 10 g / m ² or more to be sprayed on the papermaking sheet 3 in order to fully exert the effect of the blending. The upper limit of the amount of the microsilica 5 to be blended is determined by how much the microsheet 5 permeates into the paper sheet 3 by the suction box 9 during dehydration of the paper sheet 3.
Although not particularly limited, if it is 100 g / m ² or more, adhesion to the mold tends to occur during press molding. When adding the microsilica 5 to the cement-based slurry 1, the microsilica 5 is made to be in a slurry state and sprayed on the cement-based slurry 1 so that the microsilica 5 is uniformly dispersed in the cement-based slurry 1. Desirable in the above.

 The invention will now be illustrated by the examples.

Examples 1 to 5 The formulations shown in "Formulation 1" in Table 1 were dispersed in water to prepare cement-based slurries, and papermaking sheets were prepared using the apparatus shown in Fig. 1. At this time, microsilica was sprayed on the cement slurry from the nozzle of FIG. 1 so that the surface layer of the papermaking sheet was filled with microsilica. The microsilica used here was prepared by mixing Pozomix manufactured by Nippon Heavy Chemical Industry Co., Ltd. with water to prepare a 5% by weight slurry, which was quantitatively supplied by a pump and sprayed on the cement-based slurry from a nozzle. Further, microsilica was used by changing the spraying amount variously as shown in Table 2. Next, the paper sheet prepared as described above was press-molded, steam-cured at 80 ° C. for 60 hours, and then dried at 150 ° C. for 2 hours to obtain a cement-based inorganic board.

Examples 6 to 10 Cement-based inorganic boards were obtained in the same manner as in Examples 1 to 6 except that the cement-based slurry prepared from the formulation shown in "Formulation 2" in Table 1 was used.

Comparative Example 1 Using a cement-based slurry prepared with the formulation shown in "Formulation 1" in Table 1, a papermaking sheet was prepared without using microsilica. After that, a cement-based inorganic board was prepared in the same manner as in Examples 1 to 6, and an acrylic sealer was applied to the surface of the board to finish.

Comparative Example 2 A paper-making sheet was prepared using a cement-based slurry prepared from the composition shown in "Formulation 2" in Table 1 without using microsilica. After that, a cement-based inorganic board was prepared in the same manner as in Examples 7 to 12, and the surface was coated with an acrylic sealer for finishing.

The water permeability test, the planar adhesion test, and the efflorescence test were performed on the cement-based inorganic boards obtained in Examples 1 to 12 and Comparative Examples 1 and 2. The water permeability test complies with the water permeability test of JIS A 5403, and a glass tube 14 with a size of 33φ × 200 mm is attached to the surface of a test piece 13 as shown in FIG.
6φ × 200mm with glass stopper 14 and rubber stopper 16
By connecting the glass tube 17 of the dimensions of, the glass tube 17 was closed by the test piece 13, using the device, by measuring the weight change of the water enclosed in the glass tube 14,17 by measuring the water permeation amount. . The results are shown in Table 2 and shown in the graph of FIG. Further, the plane adhesion test was performed by adhering a steel jig 19 to the test piece 13 with an adhesive 18 as shown in FIG. 5 and breaking it by tensile stress. Second result
Shown in the table. Further, in the efflorescence test, as shown in FIG. 6, a gauze 21 containing water was set in the container 20, the test piece 13 was placed on the gauze 21, and left in a well-ventilated room for 3 weeks. Then, the state of occurrence of efflorescence on the surface of the test piece 13 was visually determined. The results are shown in Table 2 by clearly indicating that air florescence is generated as "x", partially efflorescence is recognized as "Δ", and that efflorescence is not generated as "○".

From the results shown in Table 2 and FIG. 4, it was confirmed that the water permeation amount was reduced and the water permeation resistance was improved by spraying the micro silica, and the planar adhesion and the efflorescence resistance were also improved by the micro silica spray. It is also confirmed.

[Effects of the Invention] As described above, in the present invention, microsilica is dispersed and blended in the cement-based slurry forming the surface layer portion of the papermaking sheet so that the surfacelayer of the papermaking sheet is filled with microsilica. Therefore, the voids in the surface layer of the papermaking sheet can be filled with microsilica having an extremely small particle size and filled to form a dense layer of the surface layer. In order to improve the strength, there is no problem of delamination or efflorescence, which occurs when a color ply layer is formed by a conventional colored cement. In addition, on the surface layer of the papermaking sheet
Since it was filled with microsilica in an amount of 10 g / m ² or more and less than 100 g / m ^2, by filling the surface layer of the papermaking sheet with microsilica in an amount of 10 g / m ² or more, the surface layer of the papermaking sheet is sufficiently It can be formed into a dense layer,
Further, by filling the surface layer of the papermaking sheet with microsilica in an amount of less than 100 g / m ^2, it is possible to prevent adhesion of the microsilica to the mold during press molding, and the papermaking sheet with the same mold. It is possible to prevent the surface layer of the paper sheet from being contaminated with the microsilica attached to the mold even if the pressing is continued, and to reduce the number of times of mold maintenance.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an example of an apparatus used in the present invention,
The figure is an enlarged cross-sectional view of a part of the cement-based inorganic board obtained by the same as above, FIG. 3 is a schematic cross-sectional view showing the method of the water permeability test, FIG. 4 is a graph showing the results of the water permeability test, and FIG. FIG. 6 is a schematic diagram showing a method of a plane adhesion test, and FIG. 6 is a schematic diagram showing a method of an efflorescence test. 1 is a cement-based slurry, 2 is a felt, 3 is a papermaking sheet, 4 is a surface layer, and 5 is microsilica.

Claims (1)

[Claims] 1. When making a paper sheet by making a cement-based slurry into paper, 10 g / m ^{2 is} added to the surface layer of the paper sheet by dispersing and blending microsilica into the cement-based slurry forming the surface layer portion of the paper sheet. A method for producing a cement-based inorganic board, which comprises filling the above-mentioned paper-making sheet with curing and curing by filling the above with less than 100 g / m ² of micro silica.