JPS5839989B2 - Inorganic architectural board materials and their manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inorganic building board material containing calcium silicate as a main component and a method for producing the same.

Architectural boards based on calcium silicate are lightweight due to their porosity, and mechanically strong due to the toughness of the calcium silicate crystals.

When architectural boards containing calcium silicate as the main component are used as exterior wall materials, a waterproof layer such as plastic coating is provided on the surface, and calcium silicate boards that have been treated with S are practically impervious to water absorption and water permeability. It won't be a problem.

It is known that water-repellent agents such as metal stearate are added to concrete, mortar, etc. cast in place to improve waterproofness, but the addition of water-repellent agents to building boards is This has not been done in the past because it would reduce the strength of the board, and by forming a waterproof layer with plastic coating,
Since sufficient waterproofness could be imparted, there was no need for this.

As is well known, the crystal structure of calcium silicate plate is 5I02 CaO due to the hydrothermal reaction between calcareous raw material and silicate raw material.
It is a crystal.

However, residual unreacted calcareous raw materials or silicic raw materials are unavoidable in terms of raw material composition.

However, since calcareous raw materials form crystals by linking Ca(OH)2 in the presence of water, it is advantageous to create a formulation that leaves unreacted calcareous raw materials; In the plate, even a small amount of unreacted calcareous raw material remains.

Incidentally, even when the above-mentioned waterproof layer made of plastic coating is provided, the inventors of the present invention have experienced that efflorescence occurs on asbestos cement boards.

The efflorescence phenomenon is caused by repeated cycles of moisture absorption and evaporation of moisture on the surface of cement products, causing free lime in the product material to precipitate on the surface of the cement product, which reacts with carbon dioxide in the air and converts calcium carbonate. By generating.

However, even in calcium silicate construction boards provided with a plastic waterproof layer on the surface, there is a possibility that efflorescence may occur as long as the above-mentioned unreacted lime remains.

Conventionally, in calcium silicate building boards, it has not been considered to make the material itself waterproof by adding a water-repellent agent, but the present inventors focused on the possibility of the above-mentioned efflorescence phenomenon and In order to prevent this, we have considered making the calcium silicate building board itself non-hygroscopic, and after conducting various studies, we have come up with the present invention.

The present invention was invented based on the above knowledge, and the inorganic building board material according to the first invention is a molded board material whose main component is calcium silicate reinforced with fibers, and a metal stearate etc. It is characterized in that an aliphatic monocarboxylic acid metal salt is added in a volume percentage of 1 to 8%.

A second invention relates to a method for manufacturing an inorganic building board material according to the first invention, and the second invention relates to an aliphatic monocarboxylic acid metal salt added to an aqueous mixture containing calcareous, silicic acid, and reinforcing fibers by volume relative to the solid content. This method is characterized by forming a sheet from a slurry containing 1 to 8% of the slurry, press-forming the sheet, and then hardening the formed sheet with high-temperature and high-pressure steam.

In the present invention, as the aliphatic monocarboxylic acid metal salts used, for example, stearate metal salts, calcium stearate, zinc stearate, sodium stearate, potassium stearate, etc. are used, and these stearate metals occupy in the plate material. The volume percentage of salt is 1 to 8%.

In the present invention, slaked lime and quicklime are normally used as the calcareous material, but lime content in cement can also be used, and therefore, cement is mixed as necessary.

As the silicic acid, diatomaceous earth, carrion, clay, etc. are used, and used materials as p filter materials and adsorbents can also be used after firing.

In addition, silica sand, quartz, etc. can also be used as the silicic acid.

Furthermore, asbestos and pulp are used as reinforcing fibers, and these fibers improve impact resistance and bending strength.

In the present invention, as a raw material, a slurry suitable for paper making with the following formulation is used, a stearic acid metal salt is added to this slurry, and this is made into paper.

Blend I Slaked lime 10-50% by weight Diatom ± 10-50% by weight Asbestos 5-20 Pulp 3-10 Silica sand 3-10 Blend ■ Cement 3-15% by weight Slaked lime 20-40 Silica sand 3-20 Diatomaceous earth 20 ~40〃 Asbestos 5~30〃 Pulp O~30〃 The metal stearate can be added directly to the slurry in the form of a powder, but this powder is heated to a temperature of 6
Dissolve in water at 0 to 90°C, and add this solution (concentration 2 to 10%).
) is preferably added.

Hereinafter, a method for manufacturing an inorganic building board according to the present invention will be explained.

In FIG. 1, reference numeral 1 denotes a first mixer, in which deflated asbestos, silica sand, pulp, and an aqueous solution of metal stearate are mixed.

2 is a second mixer, in which the mixture obtained in the first mixer 1, the calcareous raw material, and the silicic raw material are mixed.

4 is a chest in which the mixture obtained by the second mixer 2 is stirred into water to form a slurry.

5 is a paper making machine, the above-mentioned slurry is injected into a vat 51, and this slurry is passed through round cylinders 52, 52...
. This is transferred to the rotating blanket-like belt 53 in contact with the cylinders 52, 52, . . . .

When the stearate metal salt is not mixed in the vat,
The paper-made thin film on the blanket-like belt 53 is sprayed using a flow coater or a spray method, and the spraying position is more uniformly dispersed in the paper-made thin film before being suctioned.

The paper-made thin film on the belt 53 is wound around a rotating making roll 54 in contact with the belt 53, and when the thickness of the film reaches 8 to 15 mm, the rolled laminate is cut open.

61 is an iron plate, 62 is a wire mesh, and 63 is felt. On this felt 63, the above-mentioned cut original plate P is placed, and several sets of these are stacked in multiple stages and pressed.

With this press, excess moisture in the raw original plate (sheet) is removed.
The water is dehydrated through felt 63 and wire mesh 62.

After pressing, it is cured for about 10 hours under ambient conditions of 50° C. or higher and 90% RH or higher, and then final cured in an autoclave for 5 to 30 hours in saturated steam at 1 to 10 atm.

Through this final curing, CaO in the raw original plate reacts with 5in2, thereby hardening the original plate and making it into a product.

In the above manufacturing method, the water absorption rate (in air, water absorption rate after 24 hours) of the product when 0 to 10% by volume of metal stearate is added to the following formulation is as shown in Figure 2. It is.

However, the final curing conditions were a saturated water vapor pressure of 8 atm and a curing time of 12 hours, and the product was previously dried at 105° C. for 2 hours.

Blended slaked lime 30% by weight Diatomaceous earth 50 〃 Silica sand 4〃 Asbestos 10 // Pulp 6 〃 In Figure 2, curve A shows the water absorption properties when zinc stearate is added, and curve B shows the water absorption properties when calcium stearate is added. Curve C shows the water absorption properties when sodium stearate is added.

Moreover, FIG. 3 shows the decreasing characteristic of bending strength, which is almost unrelated to the type of metal stearate.

As is clear from Figures 2 and 3, calcium silicate has a low water absorption rate and sufficient bending strength by mixing stearate metal salt in a volume ratio of ■ to 8%, especially 4 to 8%. It is possible to obtain architectural board materials made of

The specific gravity X of the calcium silicate building board material obtained by the present invention is expressed as the ratio of the specific gravity Y to that without additives for those in which the amount of metal stearate added is 1 to 8% (volume percentage) as described above. /Y=1 to 0.9.

As described above, in the present invention, although the stearate metal salt is added to the calcium silicate-based raw material, S
The strength and specific gravity can be maintained at the same level as those without additives, and it is clear that there is almost no decrease in the calcium silicate reaction due to the addition of metal stearate.

As described above, according to the present invention, a calcium silicate plate having a low water absorption rate can be obtained without substantially impairing the properties of calcium silicate such as lightness and excellent strength.

Therefore, the above-mentioned concern about the efflorescence phenomenon can be eliminated, and it can also be used as an exterior wall material without a waterproof layer.

Furthermore, the plate material obtained by the present invention is extremely lightweight;
In addition, the structure is coarse and fine, making it easy to cut, nail, etc., and therefore has excellent workability.

In addition, regarding fire resistance, JIS A 1321
It has excellent characteristics that pass the first class combustion test.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of the manufacturing apparatus used in the present invention, and FIGS. 2 and 3 are charts showing the water absorption characteristics and bending strength of the inorganic building board material according to the present invention. In the figure, 4 is a chest, 5 is a paper-making machine, and P is a paper-made sheet.

Claims (1)

[Claims] 1. A molded plate material mainly composed of calcium silicate reinforced with fibers, containing an aliphatic monocarboxylic acid metal salt at a volume ratio of 1 to 1.
Inorganic construction board material characterized by 8% additive. 2. A sheet is made from a slurry in which an aliphatic monocarboxylic acid metal salt is added in an amount of 1 to 8% based on the solid content to an aqueous mixture containing calcareous, silicic, and reinforcing fibers, and the sheet is pressure-molded. A method for producing an inorganic building board material, which comprises: and then curing the formed sheet with high-temperature, high-pressure steam.