JPH02229751A - Production of inorganic plate - Google Patents

Abstract

PURPOSE:To obtain high strength and high density by compressing the specified cement compound by the rolls, compressing and molding the obtained compressed plate by a pressure device with the oppositely arranged rigid discoid bodies. CONSTITUTION:Dry powdery cement compound is obtained by blending 0-1wt.% (hereinafter wt.%) asbestos, 40-55% cement, 25-40% fine powder silica, 3-7% pulp fiber, 0.01-0.5% synthetic fiber and 10-30% fine aggregate. Then a compressed molded plate G having required thickness is obtained by supplying this compound A on a belt conveyor 2 for molding wetted by water in a laminar state and successively compressing this compound by back rolls 3, middle rolls 4 and front rolls 5. Thereafter an inorganic plate is produced by compressing and molding this compressed molded plate G at 150-250kg/cm<2> by a pressure device 6 wherein caterpillars 6A, 6B made of steel material are oppositely arranged and thereafter aging and curing the molded plate.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention is unique! ! Regarding the manufacturing method of quality board materials, in detail, it relates to the manufacturing method of noncombustible inorganic board materials. [Prior Art] It is known that asbestos fibers are very useful as reinforcing fibers when manufacturing 8L-free molded products from cement mixtures.

This asbestos fiber not only contributes to improving the strength of the molded product, but also has the advantage of providing shape retention immediately after molding. However, as asbestos fibers cause pollution, there is a strong demand for their use to be restricted or completely abolished, and various reinforcing fibers are being explored to replace asbestos, and efforts are being made to improve the bonding strength of the cement matrix to overcome the decrease in strength due to restrictions on the use of asbestos. Various supplements have been proposed.

(Problems with the prior art) Bulb fibers are promising and widely used as asbestos substitute fibers for various reasons, but in order to obtain a reinforcing effect commensurate with the addition of asbestos, bulb fibers must be added in a fairly large amount. Therefore, the non-combustibility of the building material is inhibited, and therefore the amount of pulp fiber added must be reduced.The only way to improve the strength is to increase the bonding strength of the cement matrix.

On the other hand, with the reduction of the addition of asbestos and the use of powdered silica, the compression elongation rate of the plate material during the so-called dry manufacturing process also increases, and when the formed plate material is compressed between rolls, the elongation rate is 10 to 10%. It can reach up to 15%.

For this reason, in the case of a single-layer board, a large number of minute cranks occur mainly on the back side of the formed board, which significantly reduces the strength and flexibility of the board, and in the case of a laminate with a decorative surface layer, each layer Due to the difference in the elongation rate, peeling between the eyebrows is likely to occur, and there is also the problem that the strength decreases as described above. Therefore, with molded plate materials that do not use asbestos, the compression ratio by rolls cannot be increased, so there is a problem that only plate materials with low specific gravity, high water absorption, and therefore low freeze-thaw properties can be formed. [Problems to be Solved by the Invention] In view of the above-mentioned problems, the present invention has been made in view of the above-mentioned problems.
The purpose of this invention is to obtain a method for producing an inorganic board material that can press any board material of a laminate board with a sufficiently high compressive force without the risk of cranking or glabellar peeling, and thereby has excellent freeze-thaw resistance. It is something. [Technology for Solving the Problems] That is, the method for producing II-free board materials of the present invention uses dry powder in which the amount of asbestos added is 1% by weight or less and the amount of pulp fiber added is 3 to 7% by weight. The cement mixture is molded into
・After supplying the sheet in a layered manner and compressing it with rolls using a conventional method to compress it to a predetermined thickness, the molded plate is finally compressed and molded using a pressurizing device with rigid plate-like bodies arranged facing each other. It is characterized by curing and hardening using conventional methods. [Function] The cement mixture used in this invention is the same as the conventional method except that the amount of asbestos is less than 1 weight % or no additives are added, and for example, the cement mixture is as follows.

Asbestos 0-1% by weight Cement 40.0-55.0% by weight Finely divided silica 25.0-40.0 (plain value 6000-12000ca+''/g) Pulp fiber
3.0-7.0 wt% synthetic fiber
0.01~0.5〃Fine aggregate l
O ~ 30 Additionally, a decorative layer made of the following material was laminated on the single-layer frame layer made of the above compounded material. It may also be a laminate.

Cement 40.0-60.0 Weight% Finely divided silica 20.0-60.0
(Blaine value 6000-12000cIl2/g) Pulp fiber 0.5-5.0 wt% Synthetic fiber 0. Ol ~ 0.5〃Fees
2.0 to 8.0 The method for producing an inorganic plate material in the present invention is based on a so-called dry method in which a dry powder cement compound material is supplied in layers onto a forming belt and compression-formed.

In this invention, the above-mentioned dry powder raw material is placed on a forming belt in one layer or laminated, and after being supplied, it is compressed and formed one by one using ordinary bank rolls, middle rolls, and front rolls, but finally it is formed into a plate. Pressurization is carried out between rigid plate-shaped bodies arranged facing each other, for example, by a device in which caterpillar belts whose structural members are made of steel are arranged facing each other.

At this time, the molded plate is compressed uniformly with flat front and back surfaces, so even if the pressing force is considerably high, there is little elongation of the material, and there is no possibility of cracking or peeling between the eyebrows due to differences in the elongation rate. Completely prevented.

Therefore, together with the improvement in the bonding strength of the cement matrix due to the addition of finely divided silica, it is possible to manufacture a plate material with excellent strength, flexibility, and freeze-thaw resistance.

Thereafter, the material is cured and hardened using conventional methods, but a plate material with even greater strength can be obtained by curing at high temperature and high pressure using an autoclave.

〔Example〕

Next, embodiments of the invention will be described.

(Example 1) In the formulation shown in Table 1, each raw material was mixed in a dry state,
Next, these raw materials were molded into a [1'L laminate] using a dry manufacturing apparatus 1 shown in FIG.

Table 1 First, the mixed raw material A is supplied in a layered manner onto the forming belt conveyor 2 enriched with water, and the layered raw material is transferred to the bank roll 3.
, middle roll 4 and front roll 5, and finally a caterpillar 6 whose structural members are made of steel.
The molded plate G was compression molded using a pressure device 6 in which A and 6B were arranged facing each other, while changing the pressure from 150 kg/cd to 250 kg/cd.

As shown in FIG. 2, the pressurizing device 6 presses the lower caterpillar 6A that receives the molding plate G and the upper caterpillar 6B that presses the upper surface of the molded Fic with idlers 7...7, thereby producing a predetermined result. It is constructed to obtain surface pressure.

Further, reference numeral 8 in FIG. 1 indicates a cutter for cutting the plate material into predetermined dimensions.

When the elongation rate of the layered raw material at this time was measured, the results are shown in Table 2.

In addition, in the case of conventional roll/roll compression, as shown in Table 2 Comparative Example, it was found that the elongation rate increased in proportion to the pressing force.

Next, the thickness of 5 fins obtained above, medium 27 cm, length 70 cm
The molded temporary G was autoclaved for 5 hours at 8.5 atmXl to obtain a test piece.

The bending strength, bending deflection, and dry apparent specific gravity of these test pieces were measured, and the results are shown in the right column of Table 2. The bending strength and deflection tests were conducted under the conditions of medium 270111, span 58 cm, and RR speed 16 am.

As is clear from Table 2, according to the method of the present invention, an inorganic board material with superior physical properties compared to the conventional method can be produced. Table 2 Figure 1 is a side view of the apparatus for carrying out the method of this invention;
The figure is a side view of a pressurizing device using caterpillars.

(Elongation rate is the value obtained by dividing the difference between the length after pressurization and the length before pressurization by the length before pressurization, multiplied by 100%.) [Effect] This invention is as explained above. The final pressure of the molded plate is
Since the process is carried out simultaneously on both the front and back sides using a flat plate, the elongation of the board material is kept to a very low level. Therefore, even if the use of asbestos fibers is limited to a low level, high-strength, high-density board materials can be manufactured regardless of whether they are single-layered or laminated. It is.

[Brief explanation of the drawing]

Claims (1)

[Claims] (1) A dry powdered cement mixture with an asbestos content of 1% by weight or less and a pulp fiber content of 3 to 7% by weight is supplied in layers to a forming belt, and is rolled and compressed by a conventional method. After compression molding to a predetermined thickness, the molded plate is finally compression molded using a pressure device in which rigid plate-like bodies are arranged facing each other, and then cured and hardened by a conventional method. Method of manufacturing plate materials.