JPS6016384B2 - Manufacturing method of inorganic board material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an inorganic board material, and is a method that enables the production of a calcium silicate board with low water absorption.

Calcium silicate plates are lightweight and easy to handle, and those reinforced with asbestos fibers are used as building materials, mainly as interior wall materials.

Conventionally, when manufacturing calcium silicate plates, Ca○/Sj
A drought raw material of silicic acid material and calcareous raw material with a molar ratio of 0.8 to 1.2 is molded into a plate shape, and this molded body is heated to a steam pressure of 8 k.
Cured in an autoclave for about 8 hours with saturated steam at a temperature of 9/1 or higher.

The structure of the calcium silicate plate produced in this way is
It is tobelmonite or zonolite crystal.

However, such a calcium silicate board has a high porosity and is highly water-absorbing, making it impossible to use it as an exterior wall material.

For this reason, the applicant has already proposed adding calcium stearate to reduce the water absorption of the calcium silicate plate due to its water repellency.

By the way, according to the inventor's subsequent trial production results, if a plate is formed from a raw material to which calcium stearate has been added, and the formed plate is dried once and then cured in an autoclave, it will not dry and can be cured immediately in an autoclave. I learned that the water absorption of calcium lotus acid plates can be made smaller than that of calcium lotus acid plates. The reason for this is not clear, but when the moisture in the molded plate moves to the surface of the molded plate due to evaporation, some of the calcium stearate in the molded plate also migrates toward the surface of the molded plate. This is presumed to be because the concentration of calcium stearate increases near the surface of the calcium silicate plate.

If the concentration of calcium stearate becomes high near the surface of the calcium silicate plate, water that attempts to enter the pores of the calcium silicate plate will be repelled near the surface of the calcium silicate plate, preventing it from entering the inside of the slope. As a result, the water absorption of the calcium silicate plate can be reduced more effectively. The method for manufacturing an inorganic board material according to the present invention is a method invented based on the above knowledge, in which a water-containing raw material containing a lotus acid raw material and a calcareous raw material as the main components and calcium stearate added as a water repellent is used as a board material. This method is characterized by molding the molded product into a shape, once drying the molded product to a moisture content of 10% to 20%, and then curing it with high-temperature and high-pressure steam.

The preferred blending ratios of the raw materials used in the present invention are: silicic raw material: 35 to 55 parts by weight, calcareous raw material: 0.5 to 0.8 in molar ratio of Ca○/Si02 to the silicic raw material, and cement: 5 to 15 parts by weight. parts by weight, asbestos: 5 to 20 parts by weight, calcium stearate: 1 to 4 parts by weight.

It is preferable to use calcium stearate having a melting point of 150 to 1660. In the present invention, the reason why the molded body is dried to a moisture content of 10% to 20% is that it is difficult to lower the moisture content to less than 10%, and even in such a dry state, no significant improvement in the effect can be expected. In addition, if it is more than 20%, it is thought that the migration of calcium stearate to the plate surface due to water evaporation during drying will not occur sufficiently, and the water absorption rate of the product will not be sufficiently reduced. .

Note that the drying means at this time is not particularly limited.

Therefore, natural drying or hot air drying to an extent that does not cause deterioration of calcium stearate may be used. For autoclave curing, it is preferable to use 6 to 1 hour curing with saturated steam having a vapor pressure of 3 to 7 k9/min.

In the above, "For autoclave curing, steam pressure 3 to 7 k
9/The reason why saturated steam is used and the curing time is set to 6 to 1 hour is to stop the calcium silicate reaction before tobermonite crystals are formed and to suppress the porosity of the plate material.

The reason for adding cement is to compensate for the decrease in strength of the board due to the calcium silicate reaction being stopped before tobermonite crystal formation.

The molar ratio Ca0/Si02 of the calcareous raw material to the soybean acid raw material is 35 to 55 parts by weight and 0.5 to 0. &
The reason why the amount of cement is limited to 5 to 15 parts by weight is to prevent the formation of free lime and suppress efforescence of the board.

The reason for adding asbestos is to reinforce the board material, and the blending amount of 5 to 2 parts by weight is the usual amount when asbestos is added as reinforcing fiber.

As calcium stearate, melting point 150-1650
The reason for using 0 is to eliminate melting deterioration of calcium stearate under the curing temperature, and the reason for limiting the amount added to 1 to 4 parts by weight is that if it is less than 1 part by weight, the water absorption of the board material will decrease. This is because there is no significant improvement effect, and if it exceeds 4 parts by weight, there is a concern that the mechanical strength of the plate material will decrease. Hereinafter, the present invention will be explained with reference to examples.

Calcium stearate with a melting point of 1600° is added in the range of 1 to 4 parts by weight to the following raw materials, and this is kneaded with approximately 40% water by volume. It was formed into a plate shape.

Raw material diatom ± 5 parts by weight
Lime 25 parts by weight Boltland cement; 25 parts by weight Stone
Cotton 15 parts by weight The molded article obtained as described above was air-dried until the moisture content became about 10%.

This air-dried molded body was cured in an autoclave for one feeding period using saturated steam at a steam pressure of 5k9/ground.

The water absorption rates of the above example products were measured and were as follows.

Treatment target (heavy piece) I 2 3 4 Water absorption rate 50% 32 Son 24% 22 In contrast to the above example, the water absorption rate of a comparative example product in which the molded body was directly cured by autoclaving without being air-dried was as follows. It was as follows.

Good 2 Shitsuchi Kamozaku 1 2 3 4 Water absorption rate 58% 41% 32 *27 Next, in a compounding example of 4 parts by weight of calcium stearate, which had the lowest water absorption rate in the above example, the natural The moisture content during drying is 40%, 30%, 20% and 10%,
After that, each molded product was cured in an autoclave, and the water absorption rate of the molded product was as follows.

Moisture content when drying 40% 30% 20% 10%
Water absorption rate after autoclaving 27% 24%23%
22% As is clear from the above water absorption measurement results, according to the present invention, even if the amount of calcium stearate added is the same, the water absorption of the calcium silicate plate can be effectively reduced.

Claims (1)

[Claims] 1. A water-containing raw material containing a siliceous raw material and a calcareous raw material as the main components and containing calcium stearate as a water repellent is molded into a plate shape, and the molded body is once heated to a water content of 10% to 20%.
A method for producing an inorganic board material, which is characterized by drying the material to a point where it is dry, and then curing it with high-temperature, high-pressure steam.