JPH0825182B2 - Manufacturing method of non-asbestos slate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing non-asbestos slate.

[Prior Art] Asbestos slate has been widely used as a building material for interior and exterior. The basic method for producing asbestos slate is to form a green board by a papermaking method, and then press-mold it as it is in a non-pressed state and then cure and harden it.

In addition, as an application of press molding, there is a technique in which a plurality of green plates are laminated, then press-molded and cured and cured to integrate the green plates (hereinafter, referred to as a laminated pressing method). For example, in the case of a corrugated slate, there is a technique of stacking two raw plates having a thickness half the predetermined raw plate thickness and press-molding. As a result, corrugation can be performed more easily and without damaging the raw plate.

Furthermore, the laminating press method has been used also in the production of a thick flat plate that is difficult to obtain by the papermaking method. Recently, a method for producing a gypsum board (JP-A-60-190343) and a method for producing a calcium silicate hydrate papermaking board (Japanese Patent Application No. 63-242238).
The lamination press method technology is also applied in.

When using the laminated pressing method, with asbestos slate, when press forming is performed with pressure according to the specific gravity of the final product, and then curing curing is performed, a sufficiently integrated cured body can be obtained. The interfacial peeling phenomenon did not occur on the laminated surface of the green plate. The same applies to the application of the lamination pressing method to the papermaking fiber gypsum board.

[Problems to be Solved by the Invention] On the other hand, in the production of non-asbestos slate, when the lamination press method for asbestos slate is applied as it is, the adhesion between raw plates is not sufficient or the asbestos slate is not sufficient, and thus a peeling phenomenon occurs in the product. There was a problem that it was easy.

As a method for producing a non-asbestos cement plate by a laminating press method, Japanese Patent Laid-Open No. 61-26547 has been proposed, but this technique requires the use of amorphous silica powder as a raw material and is laminated. Pressure of raw plate about 40kg / c
The integration is performed by compressing at m ² or more, preferably about 50 kg / cm ² . However, the integration of green plates by the laminated pressing method is not limited to just the press pressure conditions, but is related to many factors such as press holding time and pressurizing speed, so this technology is effective only within a very limited range. However, it could not be a fundamental technology that enables a non-asbestos slate laminating press method.

[Means for Solving the Problems] The inventors of the present invention have found that the problems can be solved as a result of earnest research for the purpose of developing a method for producing non-asbestos slate that can be applied with a laminating press method using conventional production equipment. The present invention has been completed.

That is, the present invention, a fibrous raw material selected from the group consisting of cellulose pulp, synthetic pulp, glass fiber, PVA fiber, PAN fiber, aramid fiber and carbon fiber, mainly based on Portland cement, or calcareous raw material. It consists of wet-mixing the constituent raw materials, which consist essentially of a siliceous raw material, and a powder raw material for matrix formation, and stacking a plurality of green plates formed by the papermaking method, followed by press molding and curing and curing. In the method for producing non-asbestos slate, the method for producing non-asbestos slate is characterized in that the raw plate water content before press forming is 33% or more and the decrease in raw plate water content by press forming is 10% or more. Pertain.

[Operation] When the non-asbestos slate raw plate obtained by the papermaking method is laminated and press-formed, the raw plate water content before pressing is 33% or more and the raw plate water content is determined by press forming.
It is characterized in that it is reduced to 10% or more. After that, non-asbestos slate is obtained through curing and curing.

Here, the raw plate water content described herein can be defined by the following formula: By causing the pre-adjustment of the water content of the raw plate and changing the water content by press molding, in the production of non-asbestos slate, without causing a peeling phenomenon in the product,
A laminating press method can be applied.

If the water content of green plate before press forming is less than 33%, or if the decrease in water content of green plate by press forming is less than 10%, sufficient adhesion effect cannot be obtained and the peeling phenomenon is solved. Does not reach.

When carrying out the laminated pressing method in the method for producing a non-asbestos slate of the present invention, as a method of setting the raw plate water content before pressing to 33% or more, when obtaining a raw plate by the papermaking method, a water content of 33% or more. Papermaking so that Any method may be used in which the water content is 33% or more by sprinkling water on the green sheet made into paper before press molding.

According to the method of the present invention, even when press-forming a laminated raw plate for each product, after laminating a raw plate corresponding to one product, the raw plate is used as a separator, and then the raw plate is further formed thereon. It can also be applied to the case where a plurality of products are press-molded at one time by stacking plates.

As for the operation and pressure when performing press molding, if the decrease in water content due to press molding can be made 10% or more,
Either method can be used and is practically defined by the desired bulk specific gravity of the manufactured product.

As the fibrous raw material used in the present invention, any known fiber such as cellulose pulp, synthetic pulp, glass fiber, PVA fiber, PAN fiber, aramid fiber or carbon fiber can be used.

In addition, powder raw materials for matrix formation and curing methods are roughly classified into the following two types: Portland cement as a main raw material, and hydration reaction of Portland cement by natural curing, steam curing, underwater curing, etc. to cure ; Mainly composed of calcareous raw materials (slaked lime, Portland cement, etc.) and siliceous raw materials (silica sand, diatomaceous earth, silica fume, fly ash, etc.) and cured by producing calcium silicate hydrate by autoclave curing (Note: Portland cement Contains siliceous components).

Here, the mixing ratio of the fibrous raw material and the matrix-forming powder raw material is within the range of about 2:98 to 15:85.

If necessary, the following substances can be added to the constituent raw materials composed of the above fibrous raw material and matrix-forming powder raw material: calcium silicate powder such as wollastonite, tobermorite, xonotlite; Mica mineral powder such as tight, paragonite and sericite; inorganic filler such as perlite and calcium carbonate powder; clay mineral powder such as bentonite, kaolinite and vermiculite; fibrous mineral such as palygorskite and sepiolite; porous mineral such as zeolite Powders: Silica powders such as silica sand, diatomaceous earth, silica fume, and fly ash, which are mainly composed of portrant cement and hardened by natural curing, steam curing, underwater curing and the like.

These components can be added to the above-mentioned constituent materials in a range not exceeding 35% by weight in total.

In the method of the present invention, the papermaking method is not particularly limited, and includes a cylinder-net papermaking method, a Fourdrinier-papermaking method, a flow-on method and the like, and any method can be used.

[Examples] The method of the present invention will be further described below with reference to Examples.

Example 1 84% by weight of Portland cement, calcium silicate powder
10% by weight, 1% by weight of PVA fiber, and 5% by weight of pulp were added with 10 times the amount of water relative to the solid content of the raw material, and the kneaded slurry was made into paper by a gauze paper making machine, with a thickness of 5.3 mm and a water content of 34%. I got a raw plate. Two of these raw plates were laminated and pressure-molded at 150 kg / cm ² to reduce the water content by 15%, and a flat plate having a thickness of 8.0 mm and a water content of 19% was prepared. This was naturally cured for 2 weeks to obtain a non-asbestos flat plate.

The bulk specific gravity of the obtained non-asbestos flat plate was 1.75, the bending strength (air dry) was 320 kg / cm ² , and no peeling phenomenon was observed.

Example 2 Using the same formulation and operation as in Example 1, with a thickness of 3.4 mm,
A raw plate with a water content of 38% was obtained. Two of these raw plates are stacked, 70 kg
5.7mm in thickness by reducing the water content by 11% by pressure molding at / cm ^2.
Then, a large corrugated sheet with a water content of 27% was created. This was naturally cured for 2 weeks to obtain a non-asbestos large corrugated sheet.

The bulk specific gravity of the obtained non-asbestos corrugated sheet was 1.58, the bending fracture load was 520 kg, and no peeling phenomenon was observed.

Comparative Example 1 Under the same conditions as in Example 1, a raw plate having a thickness of 5.2 mm and a water content of 34% was obtained. Two sheets of this green board are laminated and pressure-molded at 130 kg / cm ² to reduce the water content by 8%.
% Flat plate was made. This was naturally cured for 2 weeks,
A non-asbestos flat plate was obtained.

The obtained non-asbestos flat plate had a bulk specific gravity of 1.66, a bending strength of 250 kg / cm ² , and a partial peeling phenomenon was observed on the laminated surface. The bending strength was also "bulk specific gravity squared" as compared with Example 1. It showed a decrease more than expected by the "rule".

Comparative Example 2 Under the same conditions as in Example 2, a raw plate having a thickness of 3.2 mm and a water content of 39% was obtained. Two of these green plates are laminated and pressure-molded at 45 kg / cm ² to reduce the water content by 7%. The thickness is 5.8 mm and the water content is 32.
% Corrugated board was created. This was naturally cured for 2 weeks to obtain a non-asbestos corrugated sheet.

The bulk specific gravity of the obtained non-asbestos corrugated sheet was 1.52, the bending fracture load was 410 kg, partial peeling phenomenon was observed on the laminated surface, and the bending fracture load was lower than that of Example 2. It showed a decrease more than expected.

[Effects of the Invention] By the method of the present invention, a non-asbestos slate laminate can be efficiently manufactured without causing a peeling phenomenon.

Claims (1)

[Claims] 1. A fibrous raw material selected from the group consisting of cellulose pulp, synthetic pulp, glass fiber, PVA fiber, PAN fiber, aramid fiber and carbon fiber, and mainly composed of Portland cement, or a calcareous raw material and silicic acid. Non-consistent process of wet-mixing constituent raw materials consisting of powder raw materials for matrix formation, which is mainly composed of quality raw materials, and laminating a plurality of green plates formed by the papermaking method, followed by press molding and curing and curing. A method for producing non-asbestos slate, characterized in that in the method for producing asbestos slate, the water content of green board before press forming is 33% or more and the decrease in water content of green board by press forming is 10% or more.