JPH0656496A - Production of fiber-reinforced cement plate - Google Patents

Abstract

PURPOSE:To provide the method for producing a fiber-reinforced cement plate exhibiting a sufficient strength, capable of uniformly dispersing a reinforcing material even when a pulp fiber, etc., is used as the reinforcing material, in a dry method production of a molding not containing asbestos. CONSTITUTION:In the dry method cement blending for which cement, a siliceous raw material, a pulp fiber, etc., are used as the main raw materials, this method is composed of a process of uniformly admixing a pulp fiber ground to 100 to 200mum with the above-mentioned cement and siliceous raw material, a subsequent process of admixing again 1 to 3wt.% carbon or synthetic resin fiber respectively having 1 to 5mm length to the resultant mixture, spraying the mixed raw materials in layers on a molding belt and molding and curing a plate-shaped material according to the dry method. Owing to the ground pulp, generation of a fiber ball can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fiber-reinforced cement board, and more particularly to a method for producing a high-strength fiber-reinforced cement board by a dry method.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a fiber-reinforced cement board, mainly a flat roofing material, a powdery cement mixture containing reinforcing fibers is supplied in layers on a molding belt, compressed with water and rolled into a board. After molding the shaped body and cutting it to a predetermined length,
A so-called dry method is known in which a product is cured and cured by an autoclave to obtain a product. By the way, asbestos has been traditionally used as a reinforcing fiber in the method for producing a fiber-reinforced cement board, but asbestos is a cause of pollution, so use restriction or total abolition is strongly requested, and pulp is used as a substitute fiber. The use of fibers is being considered. This pulp fiber has heat resistance, alkali resistance, and the like, and is excellent in the bondability to the cement matrix, so that it is considered to be quite promising as compared with other synthetic resin fibers.

[0003]

However, the above-mentioned pulp fiber has a long fiber length.
When using 0.5 to 3 mm, it is observed that fibers are entangled with each other during dry mixing to form fiber balls.
There is a problem that it is difficult to disperse the particles uniformly. In addition, even if pulp fibers and other reinforcing fibers such as carbon fibers or synthetic resin fibers are used together, the phenomenon of becoming fiber balls cannot be avoided, and it is difficult to obtain products of uniform strength. There was a flaw.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present invention, in the case of producing a molded article containing asbestos by a dry method, evenly uses pulp fibers and the like to disperse them uniformly and to obtain sufficient strength. The purpose of the present invention is to provide a method for producing the fiber-reinforced cement board.

[0005]

That is, a method for producing a fiber-reinforced cement board according to the present invention comprises a cement, a siliceous raw material,
100% of the cement and siliceous raw material in the cement blending in the dry method using pulp fiber as the main blending raw material.
Pulp fibers crushed to ~ 200 μm are added and mixed uniformly, then 1 to 3% by weight of carbon or synthetic resin fiber of 1 to 5 mm is added to the mixture and mixed again, and the mixed raw material is placed on a molding belt. It is characterized in that it is sprayed in layers and thereafter a plate-like body is formed by a dry method and cured and cured.

[0006]

The present invention is premised on the dry method as a means for producing a fiber-reinforced cement board, and the cement, siliceous raw material,
It is the same as a conventionally known one in that a main compounding raw material such as pulp fiber is used, and there is no particular point.

In the present invention, pulp fibers crushed to 100 to 200 μm are used as pulp fibers among the above-mentioned blended materials. Grinding to this range can completely prevent the formation of fiber balls due to the entanglement of pulp fibers. Therefore, it is possible to uniformly mix the pulp fiber and the other inorganic powder material.

On the other hand, it is unavoidable that the reinforcing effect is reduced by making the pulp fibers ultra-short, and 1 to 3% by weight of carbon or synthetic resin fiber of 1 to 5 mm is added as a supplement. Bending strength is imparted by adding the long fibers. In addition, since the fiber surface of these fibers is smoother than that of pulp fibers, there is little entanglement between the fibers and fiber ball formation hardly occurs. Therefore, the shape-retaining property is ensured by adding the pulp fiber, and the bending strength is imparted by adding other long fibers.

[0009]

Embodiments of the present invention will be described below.

Example 1 Pulp fibers were crushed in a vibration mill for 5 minutes to a diameter of 1.5 mm0 and a fiber length of 100 to 200 μm. 7% by weight of this crushed pulp fiber, 50% by weight of cement and 42% by weight of silica powder are mixed by a mixer, then 1% by weight of polypropylene fiber having a fiber length of 1 mm to 4 mm is added and mixed again by the mixer and supplied to the forming belt. A 5 mm-thick plate-shaped body was rolled by a roll to form a plate-like body, which was further cut into a length of 45 cm and a width of 90 cm, and cured by autoclaving to obtain a test piece.

Comparative Example Example 1 except that pulp fibers having an average fiber length of 1 mm0 were used.
A test piece was obtained in the same manner as in.

When the JIS No. 4 bending test and the specific gravity measurement were performed on the test pieces obtained in the above Examples and Comparative Examples, the results shown in Table 1 were obtained.

[0013]

[Table 1]

[0014]

As described above, in the present invention, when the reinforcing fiber is added, the valp fiber is beautifully crushed to prevent the formation of fiber balls and the bending strength is imparted by the other long fiber. It is possible to manufacture the fiber-reinforced cement board of.

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Claims (1)

[Claims] 1. A cement compound in a dry method using cement, a siliceous raw material, pulp fiber, etc. as a main blending raw material, in which pulp fiber crushed to 100 to 200 μm is added to the cement and siliceous raw material, and the mixture is uniformly mixed. , 1 to 5 mm of carbon or synthetic resin fiber to the mixture
A method for producing a fiber-reinforced cement board, which comprises adding the mixture in an amount of 10% by weight and mixing again, spraying the mixed raw material in layers on a forming belt, and thereafter forming a plate-like body by a dry method and curing and curing.