JPH11114930A - Method for patterning fiber reinforced cement board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a deep-cut uneven pattern easily on the surface of a fiber reinforced cement board. SOLUTION: This monolayer flow-on molding method supplies a cement slurry 3 layer on a felt belt 2 equipped with a suction dewaterer 1 and produces a board by suction-dewatering. A kind of cement slurry A of ordinary blending is supplied on the belt 2 in the shape of a layer, a layer is formed, and cut into dimensions suitable for press molding. A cut uncured fiber reinforced cement board 3 is carried into a pressure reducing chamber 4 to be foaming- expanded by reduced pressure. The expanded board 3 is pressed to form an uneven pattern and cured according to an ordinary process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for patterning a fiber reinforced cement board.

[0002]

2. Description of the Related Art Conventionally, fiber-reinforced cement boards have been widely used as building materials such as wall boards and roofing materials.

[0003] Many of these fiber reinforced cement boards are provided with an uneven pattern on the surface to impart a design, and press molding is often used as a method for forming the uneven pattern. By the way, it is known that the flowability of the surface of the uncured plate material at the time of pressing should be increased in order to form a deep uneven pattern by the press molding method.

[0004] For this reason, it has been customary to increase the water content to the bareest level that can be produced, and to apply an uneven pattern directly to the surface of the formed plate material by pressing the uneven surface directly.

[0005]

However, if the content of water is excessively increased as described above, the base material flows due to the pressure at the time of pressing, which causes a problem in the production of the plate material itself, or the dehydration at the time of pressing does not work well, and the curing takes place. There has been a problem that a product is liable to cause a defect such as a cause of a large amount of efflorescence deposition during a process.

Further, if the water content is high, depending on the pressing pressure, water running occurs in the structure and the surface of the uncured cement plate at the time of pressurization, and the inorganic particles contained in the structure are caused by the water running. There is a problem that outflow occurs, which causes cracks on the product surface and a decrease in design properties due to surface roughening.

On the other hand, by changing the amount of the reinforcing fibers contained in the structure of the fiber-reinforced cement board, the length of the fibers used, or the composition of the base material, the flow of the uncured board material before pressing is reduced. It is also possible to change the amount of added fibers and the length of the fibers used, because they directly affect the strength of the product, so it is impossible to make significant changes. Due to the direct effects, the range in which the liquidity can be improved was extremely limited.

[0008] For this reason, the types of patterns and patterns that can be press-formed are limited, and there is a problem that it is particularly difficult to form a deeply carved uneven pattern by pressing. The present invention has been made for the purpose of solving the above problems,
The purpose of the present invention is to easily produce a deeply carved uneven pattern on the surface of a fiber-reinforced cement board without limitation of materials.

[0009]

According to a first aspect of the present invention, there is provided a method of patterning a fiber reinforced cement board, comprising: supplying a layer of cement slurry onto a felt belt provided with a suction dewatering device; In the on-molding method, a cement slurry composed of an ordinary compound is supplied in a layer form on the felt belt, and after layering, cut into dimensions suitable for press molding described below, and the cut uncured fiber-reinforced cement board is depressurized. It is carried into the chamber and foamed and expanded by decompression, and the foamed and expanded fiber reinforced cement board is pressed to give an uneven pattern,
Thereafter, the composition is cured and cured according to a conventional method.

[0010] After dehydration, the fiber-reinforced cement board is foamed and expanded by decompression in a decompression chamber, so that it has a porous structure, so that it is possible to form a deeply carved uneven pattern even when the water content is small.

The expanded structure is compressed again at the time of pressing to densify the structure, so that there is almost no adverse effect on the strength due to the reduced pressure foaming.

[0012]

Next, an embodiment of the present invention will be described.
40% by weight cement, silica sand
40% by weight, 10% by weight of pearlite, and 10% by weight of pulp fiber having a fiber length of 2 to 4mm as pulp fibers are prepared in a commonly used cementitious composition. Cement slurry A having a concentration of 25% was prepared. Example 1 As shown in FIG. 1, a slurry A was supplied in a layer 3 having a thickness of 15 to 25 mm on an endless felt belt 2 provided with a suction dewatering device 1 and transported while suction dewatering was performed. When the water is dehydrated to such an extent that it disappears, it is cut by the cutter 5, carried into the decompression chamber 7, decompressed to 0.2 atm, and utilizing the expansion phenomenon of air contained in the pearlite and microbubbles mixed into the slurry. The fiber-reinforced cement board 3 was expanded and expanded.

The expansion ratio was 1.3 to 1.5. Then, the foamed and expanded molded plate is transferred to a press device 6 and has a 10 cm × 5 cm brick joint shape having a depth d = 5 mm as shown in FIG. A compression press was performed for 30 seconds at a press pressure of 15 MPa on a press board 6A.

After pressing, the molded plate 3 was naturally cured for 24 hours, and then autoclaved at 170 ° C. for 15 hours to obtain a product. [Embodiment 2] As shown in FIG. 3, a press device 6 is provided in a decompression chamber 7, and a fiber-reinforced cement plate 3 made and cut by a cutter 5 in the same manner as in Embodiment 1 is installed in the press device 6. ,
After reducing the pressure and expanding the foam, the pressure was restored and immediately pressed under the same conditions as in Example 1, and then cured and cured under the same conditions as in Example 1. Comparative Example 1 A fiber reinforced cement board was obtained under the same conditions as in Example 1 except that the decompression step in Example 1 was omitted.

With respect to the above Examples and Comparative Examples, the appearance of surface irregularities and the bending strength after production as products were measured. Table 1 shows the results. As is clear from Table 1, in Examples 1 and 2, the deeply carved uneven pattern was clearly provided, and almost no cracks around the uneven pattern were observed.

On the other hand, in the comparative example, an unclear portion such as a chip was found at the edge portion of the uneven pattern, and a number of cracks running along the edge were found on the surface of the convex pattern. In addition, the bending strength in Table 1 is based on the JIS No. 4 bending test.

[0017]

[Table 1]

[0018]

As described above, according to the present invention, even if the water content at the time of making the fiber reinforced cement board is low, the uncured fiber reinforced cement board is expanded and expanded by reducing the pressure to obtain a porous state. After pressing, deep uneven patterns can be provided with good reproducibility even if the moisture content of the uncured fiber reinforced cement board is low.

In addition, there is no need to adjust the amount of suction and dehydration, which was conventionally difficult, so that there is an effect that the implementation is easy. Since the expanded fiber-reinforced cement board is compressed again during pressing, the dense state of the tissue is maintained, and the strength is hardly reduced.

[Brief description of the drawings]

FIG. 1 is a side view of an apparatus for performing a method according to the first aspect of the present invention.

FIG. 2 is an enlarged sectional view of a main part of a concavo-convex pattern type of a press machine.

FIG. 3 is a side view of an apparatus for performing the method according to another embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Suction dehydration apparatus 2 Endless felt belt 3 Cement layer 4 Decompression chamber 5 Cutter 6 Press board

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI E04C 2/04 E04C 2/04 C (72) Inventor Kazuyuki Komatsu 1-1-1 Hama, Amagasaki-shi, Hyogo Kubota R & D Co., Ltd. Inside

Claims (1)

[Claims] 1. A one-layer flow-on molding method in which a cement slurry is supplied in a layer form on a felt belt provided with a suction dewatering device, and is suction-dewatered to make a plate. After being supplied in layers and stratified, it is cut into a size suitable for press molding described below, and the cut uncured fiber reinforced cement board is carried into a decompression chamber, expanded and expanded under reduced pressure, and the expanded fiber reinforcement is cut. A patterning method for a fiber-reinforced cement board, which comprises pressing a cement board to form an uneven pattern, and then curing and curing in accordance with a conventional method.