JPH0725084B2 - 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 reason, conventionally, the adhesive 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-mentioned points, and efflorescence forms a dense surface layer for enhancing waterproof performance and enhancing planar adhesion without problems such as delamination. It is an object of the present invention to provide a method for producing a cement-based inorganic board that can be used.

DISCLOSURE OF THE INVENTION However, the method for producing a cement-based inorganic plate according to the present invention is prepared by dispersing the micro-silica 5 in water together with a dispersant when the cement-based slurry 1 is formed into a paper sheet 3. Micro-silica slurry 2 made into paper sheet 3
The surface layer 4 of the paper sheet 1 is mixed and dispersed in the cement-based slurry 1 to form the surface layer 4, and the surface layer 4 of the paper sheet 1 is filled with microsilica 5 to cure and cure the paper sheet 1. The present invention will be described in detail.

Cement-based slurry 1 is prepared by dispersing cement or other hydraulic substance such as gypsum, reinforcing fibers and filler in water.
The paper-making sheet 3 can be prepared by paper-making the paper with, for example, a Fourdrinier paper making machine. That is, as shown in FIG. 1, a part of the endless felt 7 is made to face the bottom of the slurry tank 8 to which the cement-based slurry 1 is supplied, and the bottom of the slurry tank 8 is provided on the back side of the felt 7. Is provided with a suction box 9 connected to a vacuum pump. When the felt 7 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 7. The solid content in the cement-based slurry 1 remains on the surface of the felt 7, and the papermaking sheet 3 made of the solid content of the cement-based slurry 1 is made on the surface of the felt 7. Here, while the felt 7 travels in the slurry tank 8, the solid content of the cement-based slurry 1 is gradually deposited on the surface of the felt 7 and grows on the paper sheet 3, and thus the surface layer of the paper sheet 3 is formed. 4 is formed by the cement-based slurry 1 in the end of the slurry tank 8 on the outlet side of the felt 7.

Then, in the present invention, in the slurry tank 8, at the end of the felt 7 on the outlet side, the cement-based slurry 1 is sprayed with the microsilica slurry 2 prepared by dispersing the microsilica 5 in water from the nozzle 12 at the tip of the pipe. The microsilica 5 is dispersed in the cement-based slurry 1 so that the microsilica 5 is filled in the surface layer 4 when the surface layer 4 of the papermaking sheet 3 is formed by the cement-based slurry 1. 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 of the slurry tank 8. The paper sheet 3 thus formed on the surface of the felt 7 is dehydrated in the suction box 1 in the dehydration process, and after the paper sheet 3 is taken out from the felt 7, it is well known that press molding, curing and drying are performed. The cement-based inorganic board A such as a building material is finished through the steps.

Here, in preparing the microsilica slurry 2, in the present invention, a dispersant is added to water together with the microsilica 5 to prevent coagulation between particles of the microsilica 5 in water. It is intended to disperse evenly in the slurry 2, and by dispersing the microsilica 5 in the microsilica slurry 2 using the dispersant in this way, a sufficient effect can be achieved by spraying a small amount of the microsilica 5. I am able to get it. That is, in the microsilica slurry prepared by simply mixing the microsilica 5 with water, the dispersion of the microsilica 5 is insufficient and the amount of the microsilica 5 penetrating into the inside of the papermaking sheet 3 is small, so that a predetermined effect is obtained. For this purpose, it is necessary to increase the amount of the microsilica 5 sprayed, but by uniformly dispersing the microsilica 5 in the microsilica slurry 2 using a dispersant, the penetration of the microsilica 5 into the inside of the paper sheet 3 is suppressed. Therefore, it is possible to obtain a sufficient effect by spraying a small amount of microsilica 5. The dispersant is not particularly limited as long as it has an ability to disperse the microsilica 5 in water, and for example, a water reducing agent such as a lignin sulfonate salt or a high performance water reducing agent can be used. The amount of the dispersant blended is not particularly limited as long as it is possible to recursively determine the optimum value in accordance with its type and characteristics.

Therefore, the micro silica 5 is a fine silica powder having a very small particle size of about 1/100 μ to 5 μ, and therefore, in the surface layer 4 of the papermaking sheet 3, micro silica is formed in the voids between the cement matrix, the reinforcing fibers and the filler. The silica 5 is filled to fill this void, and the micro silica 5
The surface layer 4 of the cement-based inorganic plate A becomes a dense layer as shown in FIG. 2 due to the sealer effect and the surface reinforcing effect.
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 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, and the microsilica 5 is integrated with the base material portion of the cement-based inorganic plate A to effectively prevent peeling of the surface layer 4. At the same time, the free alkali near the surface of the cement-based inorganic plate A can be fixed to effectively prevent the occurrence of efflorescence. The blending amount of the microsilica 5 is not particularly limited because it is affected variously by the kind and blending amount of the dispersant.
In order to fully bring out the effect of the blending, it is desirable to spray the paper sheet 3 in an amount of 5 g / m ² or more.
The upper limit of the compounding amount of the microsilica 5 is determined by how far the suction sheet 9 penetrates into the paper sheet 3 during dehydration of the paper sheet 3, and is not particularly limited, but 100 g / m 2 ^{If the number is 2} or more, adhesion to the mold tends to occur during press molding.

The invention will now be illustrated by the examples.

Examples 1 to 5 The formulations shown in Table 1 were dispersed in water to prepare cement-based slurries, and papermaking sheets were prepared with the apparatus shown in FIG. At this time, the microsilica slurry was sprayed on the cement-based slurry from the nozzle of FIG. 1 so that the surface layer of the papermaking sheet was filled with the microsilica. Here, the microsilica slurry was prepared by mixing Pozomix manufactured by Nippon Heavy Chemical Industry Co., Ltd. with water so that the concentration of microsilica was 5% by weight, and as a dispersant, Pozoris No. 5 manufactured by Pozzolis Co., Ltd.
125 g of this pozzolis was diluted with water to prepare a concentration of 25% by weight using L, and the microsilica slurry was used while the dispersant was added to and mixed with the microsilica slurry. This microsilica slurry is supplied in a fixed amount by a pump, and the spray amount from the nozzle is set so that the spray amount of microsilica on the papermaking sheet is 15 g / m ^2, and the addition amount of the dispersant to the microsilica slurry is set to 2 Various changes were made as shown in Table. 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.

Conventional Example Using a cement-based slurry prepared with the formulation shown in Table 1, Example 1 without using a microsilica slurry
Papermaking sheets were prepared in the same manner as described in Nos. After that, a cement-based inorganic plate was prepared in the same manner as in Examples 1 to 5, and the surface was coated with an acrylic sealer for finishing.

Comparative Example 1 A cement-based inorganic board was obtained in the same manner as in Examples 1 to 5, except that the microsilica slurry was used without adding a dispersant.

The water permeability test, the plane adhesion test, and the efflorescence test were performed on the cement-based inorganic boards obtained in Examples 1 to 5 and the conventional example and the comparative example 1. Water permeability test is JIS A 54
According to the water permeability test of 03, a glass tube 14 having a size of 33φ × 200 mm is adhered to the surface of the test piece 13 as shown in FIG.
Connect a glass tube 17 with a size of 0 mm and attach the glass tube 17 to the test piece 1
This was performed by measuring the change in weight of water enclosed in the glass tubes 14 and 17 and measuring the amount of water permeation using an apparatus closed at 3. 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. 4 and breaking it by tensile stress. Further, in the efflorescence test, as shown in FIG. 5, 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 of each of the above tests are shown in Table 2. In Table 2, in the efflorescence test, those in which efflorescence was clearly generated were indicated by "x", those in which efflorescence was partially observed were indicated by "△", and those in which efflorescence were not occurred were indicated by "○". .

As is clear from the comparison between the results of Table 2 and the conventional example, it is confirmed that the amount of water permeation is reduced and the water permeation resistance is improved by the application of microsilica, and the planar adhesion and effluent resistance are also improved. It is also confirmed that the susceptibility is also improved by spraying microsilica. Further, as is clear from the comparison between Comparative Example 1 and each Example, by adding a dispersant to the microsilica slurry, water permeation resistance and planar adhesion,
It is confirmed that the effect of efflorescence resistance can be enhanced.

Examples 6 to 11 It is confirmed from the results shown in Table 2 that the addition amount of the dispersant (pozzolith) to the microsilica slurry is preferably 0.2% by weight or more. Therefore, the addition amount of the dispersant was set to 0.3% by weight. A cement-based inorganic board was obtained in the same manner as in Examples 1 to 5, except that the microsilica slurry was used and the amount of microsilica sprayed onto the papermaking sheet was changed variously as shown in Table 3.

Comparative Examples 2 to 7 Cement-based inorganic boards were obtained by using microsilica slurries containing no dispersant and varying the amount of microsilica sprayed onto the papermaking sheet in the same manner as in Examples 6 to 11.

The cement-based inorganic boards obtained in Examples 6 to 11 and Comparative Examples 2 to 7 were subjected to a water permeability test, a plane adhesion test and an efflorescence test, and the results are shown in Table 3.

As a result of Table 3, in the case where the dispersant is added to the microsilica slurry (Example), a sufficient effect can be obtained with a spray amount of the microsilica of about 5 to 10 g / m ² . It was confirmed that a dispersion amount of microsilica of 10 to 15 g / m ² or more was necessary for the one used without adding the dispersant to the microsilica slurry (comparative example), and the dispersant was added to the microsilica slurry. It is confirmed that the effect can be obtained by spraying a small amount of microsilica.

[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 by filling microsilica with an extremely small particle size to make the surface layer a dense layer, thus improving the water resistance and planar adhesive strength of the cement-based inorganic board. In letting you
The problem of delamination and efflorescence unlike the case of forming a color ply layer with conventional colored cement does not occur, and a microsilica slurry prepared by dispersing microsilica in a water together with a dispersant is used as a cement. Since it was mixed and dispersed in the system slurry, the dispersant acts to uniformly disperse the microsilica in the microsilica slurry to enhance the permeation of the microsilica into the interior of the papermaking sheet and to disperse a small amount of microsilica. It is possible to obtain a sufficient effect.

[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 water permeability test, and FIG. 4 is a schematic view showing the method of planar adhesion test. FIG. 3 is a schematic diagram showing a method of an efflorescence test. 1 is a cement-based slurry, 2 is a microsilica slurry,
3 is a papermaking sheet, 4 is a surface layer, and 5 is microsilica.

Claims (1)

[Claims] 1. When a cement-based slurry is made into a paper to produce a paper sheet, a micro-silica slurry prepared by dispersing microsilica in water together with a dispersant is used as a cement-based slurry for forming a surface layer portion of the paper sheet. A method for producing a cement-based inorganic board, which comprises mixing and dispersing to fill a surface layer of a paper sheet with microsilica, and curing and hardening the paper sheet.