JP3229161B2 - 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 as a building material.

[0002]

2. Description of the Related Art In a cement-based inorganic plate, a raw material mixture mainly composed of cement and reinforcing fibers is dispersed in water to form a slurry, and the slurry is formed into a mat by dewatering, and the mat is subjected to primary curing and secondary curing. Wet method to cure and harden,
Alternatively, it is manufactured by a dry method in which the raw material mixture is sprayed on a carrier plate to form a mat, and the mat is pressed and then primary cured and secondary cured to be cured. Conventionally, in the above-mentioned method for producing an inorganic plate, primary curing is performed under high humidity and high temperature conditions of, for example, a relative humidity of 85 to 90% and a temperature of 80 ° C. However, in the primary curing under such high-humidity and high-temperature conditions, an efflorescence phenomenon in which calcium hydroxide precipitates due to a cement reaction in the mat during curing occurs, and when such an efflorescence phenomenon occurs, the coating suitability of the inorganic plate becomes large. Failure occurs. As a method for preventing the occurrence of the efflorescence phenomenon, a method of performing primary curing under a low temperature condition of 30 to 80 ° C has been proposed.

[0003]

However, even in the primary curing under the low temperature conditions as described above, the efflorescence phenomenon could not be reliably prevented.

[0004]

According to the present invention, as a means for solving the above-mentioned conventional problems, a mat comprising a raw material mixture mainly composed of cement and reinforcing fibers has a water content of 15 to 3%.
An object of the present invention is to provide a method for producing an inorganic plate which is subjected to primary curing after being kept at 5% by weight and then secondary curing.

In the present invention, a raw material mixture mainly composed of cement and reinforcing fibers is formed into a mat by a wet or dry method. Examples of the cement used in the present invention include Portland cement, blast furnace slag cement, silica cement, fly ash cement, alumina cement and the like.

In the present invention, it is desirable to add silica powder and / or silica-containing powder as an aggregate for reinforcing cement or to cause a calcium silicate reaction. Stone powder, silica fume and the like are exemplified.

In the present invention, wood fibers and / or inorganic fibers are used as reinforcing fibers. Examples of the wood fibers include pulp, wood wool, and wood chips, and examples of the inorganic fibers include sepiolite and wollastonite. Is done.

In the present invention, fillers such as shirasu balloon, perlite, fly ash, blast furnace slag, zeolite, bentonite, diatomaceous earth, etc., and cement hardening accelerators such as calcium chloride, water glass, etc., if desired, other than the above-mentioned components. May be added.

The mixing ratio of the cement to the silica powder and / or the silica-containing powder is usually from about 3: 7 to 7: 3 by weight, and the wood fiber is usually contained in the raw material mixture in an amount of from 1 to 7.
About 8% by weight is added. When wollastonite is added, usually about 3 to 20% by weight is added. When fly ash is added, usually 3 to 2 parts are added to the raw material mixture.
About 0% by weight is added.

In the wet method, the raw material mixture is dispersed in water to form a slurry, and the amount of the raw material mixture in the slurry is usually 8 to 15% by weight. The slurry prepared as described above is formed by a usual method, and after the forming, if necessary, the formed material is subjected to press dehydration to perform primary curing and secondary curing as a mat. In the case of the dry method, the raw material mixture is sprayed on a carrier plate. In this case, the water content of the raw material mixture is adjusted to 40 to 60% by weight to supply the water necessary for the cement hardening reaction.
In this case, the mat formed on the conveying plate is firstly cured in a pressed state, and then subjected to secondary curing. Curing conditions are usually 30 to 80 ° C and 6 to 48 hours for primary curing, and 2 days to 2 weeks or 14 hours at room temperature and normal pressure for secondary curing.
The temperature is 0 to 200 ° C. and 6 to 10 hours, and the moisture content of the mat in the primary curing is maintained at 15 to 35% by weight. When the moisture content of the mat exceeds 30% by weight, the temperature of the primary curing is desirably 50 ° C. or less. By such low-temperature curing, the mat easily absorbs dew condensation water, and the occurrence of the efflorescence phenomenon is more reliably suppressed.

[0011]

When a mat consisting of a raw material mixture mainly composed of cement and reinforcing fibers is primarily cured, the moisture content is 15 to 35.
When the weight% is maintained, the mat itself absorbs the condensed water formed on the surface and the periphery of the mat, so that the excess water is eliminated and the efflorescence phenomenon can be suppressed.

[0012]

【Example】

[Examples 1-3, Comparative Examples 1-3] 42% by weight of cement
(Hereinafter simply referred to as%), silica sand powder 42%, wood pulp 5%, wollastonite 5%, and other inorganic substances 6% as raw materials, water is added to a mixture of the raw materials, and the mixture is stirred and dispersed.
The paper was molded and formed according to a conventional method to obtain a wet mat having a thickness of 8.0 mm. Next, the wet mat is cut into a predetermined size, the press pressure is adjusted, and the wet mat is dehydrated to a moisture content shown in Table 1 to obtain a green plate having a thickness of 6.0 mm. When the water content was 20% or less, hot air drying was also performed to adjust the water content. The green sheets are stacked on a cart and subjected to primary curing under the conditions of a temperature of 80 ° C. and 6 to 8 hours. Further, secondary curing was performed at normal temperature and normal pressure for 10 days to obtain an inorganic plate. Table 1 shows the physical properties of the obtained inorganic plate.

[0013]

[Table 1] * 1: 40-60% generated on the entire surface * 2: 20-40% generated on the periphery * 3: Only 5% or less on the periphery

According to Table 1 above, the moisture content of the mat was 15 to 3
When primary curing is performed under the condition of 5% by weight, the occurrence of the efflorescence phenomenon can be extremely reduced, and the bending strength,
Physical properties such as bending Young's modulus have been improved, and a stable product has been made. Further, the product moisture content is close to the equilibrium moisture content, and a drying step after the secondary curing is not required. On the other hand, in Comparative Examples 1 and 2 in which the moisture content of the mat exceeds 35% by weight, the occurrence of the efflorescence phenomenon is remarkable, and the moisture content of the product is high. In the case of Comparative Example 3, unreacted cement remains due to lack of moisture, and the curability after primary curing is not sufficient. Therefore, the handling property is poor, and there is a possibility of deformation during transportation and handling.

[0015]

According to the present invention, therefore, the efflorescence phenomenon at the time of primary curing of a mat composed of a raw material mixture mainly composed of cement and reinforcing fibers can be suppressed, so that the paintability of the product can be maintained well, In addition, the bending strength is improved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C04B 14:38) C04B 14:38) C

Claims (1)

(57) [Claims] 1. A method for producing an inorganic plate, comprising: a mat consisting of a raw material mixture mainly composed of cement and reinforcing fibers; a primary curing while maintaining a water content of 15 to 35% by weight, followed by a secondary curing.