JPH04305409A - Manufacturing method of fiber reinforced cement board - Google Patents

Abstract

PURPOSE:To prevent the strength in longitudinal direction of a product from being reduced as fully as posible in spite of the mill-forming by rolls in the dry manufacture using the cement compound without asbestos. CONSTITUTION:The cement compound mixed with the reinforcing fiber except asbestos is fed on a forming belt like a lasyer and is compressed into prescribed thickness by a roll R after water-adding and then after a bandlike plate 1 has been continuously molded, it is cut so that the width direction (arrow Y) of said bnadlike plate becomes the length direction (arrow X) of a bandlike molded object, and the cut object is cured.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing fiber-reinforced cement boards, and more particularly to an improved dry manufacturing method for fiber-reinforced cement boards containing asbestos-free.

0002

[Prior Art] Conventionally, fiber-reinforced cement materials have been very widely known as roofing materials, wall panels, etc., and as a manufacturing method for these materials, as shown in FIG. Compound B was supplied in layers and compressed to a predetermined thickness by a water-added upper roll R to continuously form a strip plate, and in the case of roofing material G, for example, these were combined with each other as shown in Figure 2. In the past, products were cut into shapes and cured to harden.

0003

[Problems with the prior art] However, when compressing the cement mixture B' supplied in layers in the dry manufacturing method using rolls, the strip plate is rolled by the rolls R, so that the continuous direction (arrow X) and the width direction ( When the structure becomes coarser and denser in the direction of arrow Y) and the product is cut out as shown in Fig. 2, the bending resistance force in the length direction (arrow
In particular, when the difference in dimension between the length direction (arrow X) and the width direction (arrow Y) is large as shown in FIG. 3, it is easy to break. In particular, in recent years there has been a strong demand for restrictions or complete abolition of the use of asbestos fibers from the perspective of pollution prevention, and in the current situation where asbestos fibers with such excellent reinforcing effects cannot be used, the above problem has become more prominent. .

0004

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the present invention aims to reduce the strength loss in the longitudinal direction of the product as much as possible, even though rolling forming is performed using rolls in a dry manufacturing method using an asbestos-free cement mixture. The purpose of this invention is to provide a method for manufacturing a fiber-reinforced cement board that prevents the above.

[0005]

[Means for Solving the Problems] That is, the method for manufacturing a fiber-reinforced cement board of the present invention involves supplying a cement mixture containing reinforcing fibers other than asbestos onto a forming belt in a layered manner, and applying water to the upper roll to obtain a predetermined thickness. The method is characterized in that after compressing and continuously forming a band-like plate, the band-like plate is cut so that the width direction of the plate-like molded product is in the length direction of the plate-like molded product, and the cut product is cured and hardened.

[0006]

[Operation] The cement mixture used in this invention has the same composition as the conventional one except that the reinforcing fibers are fibers other than asbestos, such as pulp fibers, polypropylene fibers, vinylon fibers, etc. There is nothing to note. Further, regarding the dry manufacturing method for forming the strip, the steps from layering to compressing with rolls to a predetermined thickness are exactly the same as conventional ones.

[0007] In the present invention, when cutting the compression-molded strip plate into a product shape, the strip plate is cut so that the width direction of the strip plate corresponds to the length direction of the plate-shaped molded product. In this case, the rolled strip plate is rolled in the length direction, and the bending force in that direction is reduced, and the reduction in the width direction is not as great as in the length direction. Therefore, in the structure of the cut product, the strength in the length direction of the product is stronger than the strength in the width direction. Therefore, a product with excellent strength can be obtained even though the manufacturing method is the same as the conventional one.

[0008]

[Example] Next, an example of the present invention will be described. Same as conventional cement mixture with 40-50% by weight of cement, 40-50% by weight of silica powder, 3-5% by weight of pulp fibers as reinforcing fibers, and 0.5-1.0% by weight of polypropylene fibers. 5mm thick and wide by dry manufacturing method 9
A 00 mm uncured cement strip 1 is formed as shown in FIG. 1, and then cut using a roll cutter 2 so that the width direction (arrow Y) of the strip 1 becomes the length direction (arrow X) of the plate-shaped molded product 3. It was cut into pieces of 450 mm. Next, this plate-shaped molded product 3 was cured and cured in an autoclave.

[0009] As a comparative example, a plate-shaped molded product was obtained by cutting a band-shaped plate obtained by the same method as in the above example into a length L of 900 mm and width of 450 mm as shown in Fig. 2, and curing and curing under the same conditions as in the example. I got it. Next, a bending test in the length direction (arrow
In the case of the example, the average bending strength was 170 kg/cm2, and the deflection was 13.2 mm.
On the other hand, the comparative example had an average bending strength of 140k.
g/cm2 and the same deflection was 12.5 mm, indicating that the molded product obtained by the present invention exhibited considerably excellent bending strength.

0010

[Effects of the Invention] As explained above, according to the method of the present invention, the difference in longitudinal and lateral strength of a strip plate whose thickness has been made uniform by roll rolling in the dry method is cut according to the product shape, so that even the same mixed material can be cut. Despite using the same manufacturing method, the bending strength, deflection, etc. of the resulting product can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the invention.

FIG. 2 is a plan view of a conventional example.

FIG. 3 is a side view showing the dry manufacturing process.

[Explanation of symbols]

1 Uncured cement strip 2 Roll cutter 3　　　Plate-shaped molded product

Claims (1)

[Claims] Claim 1: A cement mixture mixed with reinforcing fibers other than asbestos is supplied in layers onto a forming belt, compressed to a predetermined thickness by a water-added upper roll, and after continuously forming a band-like plate, the width of the band-like plate is determined. A method for manufacturing a fiber-reinforced cement board, which comprises cutting the plate-shaped molded product in the longitudinal direction, and curing and curing the cut product.