JPH068001B2 - Method for manufacturing fiber cement board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a fiber cement board used for building materials and the like.

[Background Art] Conventionally, this type of fiber cement board used for roofing materials has been manufactured as follows. First, as shown in FIG. 4, a cement slurry 1 prepared by dispersing and mixing asbestos, pulp, cement and the like in water is formed into a plurality of papermaking bats 2,
2 and 2 are supplied, the cement slurry 1 is made up by the paper making cylinder 4 arranged in each paper making bat 2, and is transferred to the felt 6 as a wet mat 5. Next, this wet mat 5 is wound several times around a making roll 12 to obtain a green sheet having a predetermined thickness. Then, the green sheet is separated from the making roll 12 and dehydrated by a press, followed by curing and then cutting. It is a product that undergoes processing steps such as painting. However, when the fiber cement board manufactured in this manner is applied as a roofing material, there is a drawback that when the upper surface of the fiber cement board A is stepped on, a crack will occur when stepped on. That is, since the hardened cement material is strong against the compressive force F ₁ but weak against the tensile force F ₂ , it easily causes a step crack. Therefore, in order to solve such a problem of trampling, the surface of the wet mat 5 is sprinkled with a fiber cement slurry 3 containing reinforcing fibers to reinforce the inside of the fiber cement plate A as shown in FIG. There is a method of forming a fiber layer. However, in this manufacturing method, the dispersion state of the reinforcing fibers is bad and the strength of the fiber cement plate A is lowered, and when the reinforcing fibers of long fibers are used, the strength is not evenly dispersed. Only fibers could be used and therefore the reinforcing effect was not sufficient. (For example, refer to Japanese Patent Publication No. 55-23529). In addition, 9 in the figure
Is a cement layer formed of the wet mat 5 of the cement slurry 1.

[Object of the Invention] The present invention has been made in view of the above points, and provides a method for producing a fiber cement board which can improve the cracking resistance when used as a roofing material, for example. It is intended.

DISCLOSURE OF THE INVENTION That is, according to the method for producing a fiber cement plate of the present invention, the papermaking bats 2b and 2c to which the cement slurry 1 containing cement as a main component is supplied, and the fiber length 6 in the cement slurry 1 are provided.
The papermaking bat a2 to which the fiber cement slurry 3 mixed with the reinforcing fiber made of vinylon fiber of ˜15 mm is supplied, and the cement slurry 1 and the fiber cement are placed in the papermaking cylinder 4 provided in the papermaking bat 2. Each of the slurry 3 is made into paper, and the cement layer 9 formed by the cement slurry 1 and the fiber reinforcement layer 8 formed by the fiber cement slurry 3 are transferred onto the felt 6 as a wet mat 5 in a laminated state, and then, A plurality of the wet mats 5 are wound around the making roll 12, and the green sheet 7 in which a plurality of layers of the wet mat 5 are laminated is cut out from the making roll 12, and then the green sheet 7 is cured. By making paper as fiber cement slurry 1, the fiber length is 6 to 15 mm. Even than as uniformly dispersed is obtained by achieving the above object.

The present invention will be described in detail below. First, the preparation of the cement slurry 1 and the fiber cement slurry 3 will be described. The cement slurry 1 may have the same composition as the conventional one. That is, 7 to 5 or 6 class asbestos
15 parts by weight, 5 to 15 parts by weight of filler such as silica sand, 1 to 2 parts by weight of papermaking auxiliary agent such as pulp, and 70 to 85 parts by weight of cement components such as blast furnace cement, ordinary Portland cement and fly ash cement. It was prepared by dispersing and mixing the solid content and the mixed water of 2.5 to 3.5 times the solid content. The fiber cement slurry 3 is a mixture of the cement slurry 1 and the reinforcing fiber cement slurry 10. The reinforcing fiber cement slurry 10 is prepared by mixing and dispersing reinforcing fibers having a fiber length of 6 to 15 mm and the cement component in water. The reinforcing fiber cement slurry 10 and the cement slurry 1 can be mixed at any ratio. For example, vinylon can be used as the reinforcing fiber. The cement slurries 1 and 3 thus prepared are supplied into a plurality of papermaking vats 2a, 2b and 2c as shown in FIG. In this embodiment, an example in which three papermaking bats 2 are arranged is shown, but the number of papermaking bats 2 is not limited to this, and two or four or more papermaking bats 2 may be provided. The above-mentioned fiber cement slurry 3 is fed into the first papermaking bat 2a on the front side of the felt 6 in the conveying direction, and the reinforcing slurry is not mixed in the second and third papermaking bats 2b, 2c on the rear side of the conveying direction. Preference is given to supplying 1. A papermaking cylinder 4 is disposed in each papermaking bat 2, and the papermaking cylinder 4 is
By cement slurry 1 and fiber cement slurry 3
Is transferred to the felt 6 as a wet mat 5. Here, when a cross-sectional view of the wet mat 5 is shown, as shown in FIG. 2, one layer on the back surface becomes the reinforcing fiber layer 8 containing reinforcing fibers, and the other upper layer becomes the cement layer 9 in which the reinforcing fibers are not dispersed. Is. Next, this wet mat 5 is wound several times around a making roll 12 and when it becomes a predetermined thickness, it is cut off from the making roll 12 to obtain a green sheet 7 having a predetermined thickness, and thereafter, processing such as pressing and curing is performed. The fiber cement board A is obtained through the steps.

Then, by supplying the fiber cement slurry 3 containing the reinforcing fibers into the papermaking bat 2a and making the paper from the papermaking bat 2a, the reinforcing fibers are dispersed in a large amount of water and the fiber length Is 6 to 15 mm and is evenly dispersed, and therefore, even when the fiber cement slurry 3 is made into a paper and laminated as the reinforcing fiber layer 8 with another cement layer 9, the adhesive strength between the layers decreases. There is no such thing. A cross-sectional view of the manufactured fiber cement board A is shown in FIG. 3, in which a plurality of reinforcing fiber layers 8 containing reinforcing fibers are formed between the cement layers 9, and the fiber cement board A is formed by the reinforcing fiber layers 8. The bending strength and the like can be improved. here,
When the fiber length of the reinforcing fiber is less than 6 mm, the reinforcing effect is small, and when the fiber length exceeds 15 mm, the mixing dispersibility is deteriorated. When the fiber cement board A is used as a roofing material, it is used so that the reinforcing fiber layer 8 is on the lower side, and the reinforcing force of each reinforcing fiber layer 8 is improved. It is strong against bending strength from the upper surface side.

That is, in order to enhance the reinforcing effect of the fiber cement board A, a reinforcing fiber cement slurry 10 made of vinylon fiber having a fiber length of 6 to 15 mm is mixed with the cement slurry 1 to form a fiber cement slurry 3, and this fiber cement slurry 3
To form a reinforcing fiber layer 8. By increasing the fiber length of the vinylon fiber to 6 to 15 mm, the dispersed state of the reinforcing fiber is improved, and the vinylon fiber has a fiber length of 6 to 15 mm. It has the property that even if it becomes long, it is hard to break and it is hard to get entangled and solidify, and besides,
Among the resin fibers, vinylon fiber has excellent heat resistance, and since autoclave curing at high temperature can be performed in the same manner as conventional glass fiber, the fiber cement board A comprising the reinforcing fiber layer 8 and the cement layer 9 described above. Has a sufficient reinforcing effect, and even if it is used as a roofing material, it is possible to reliably prevent the occurrence of stepping cracks.

Next, the present invention will be specifically described based on Examples.

Examples The following are examples of each formulation of cement slurry and reinforcing fiber cement slurry. The cement slurry prepared in this manner is used for the second and third papermaking bats 2b and 2c shown in FIG.
The fiber cement slurry prepared by mixing the cement slurry with the reinforcing fiber cement slurry is supplied into the first papermaking vat 2a. Then, the cement slurry and the fiber cement slurry are made into paper by a paper making cylinder arranged in each paper making bat and transferred onto a felt as a wet mat, and the wet mat is wound around a making roll four times, and then a green sheet. Was cut from a making roll, and then this green sheet was pressed and cured to obtain a fiber cement board.

<Composition of cement slurry> Asbestos: 15% by weight Pulp: 1% by weight Silica sand: 10% by weight Cement: 74% by weight Water: Proper amount <Composition of reinforcing fiber cement slurry> Vinylon (10 mm 2 denier): 3% by weight Cement: 97 % By weight of water ... Comparative example Comparative example A fiber cement board was obtained in the same manner as in the above-mentioned example except that vinylon (2 denier) having a fiber length of 3 mm was used as the reinforcing fiber used in the reinforcing fiber cement slurry.

Next, as a result of measuring the bending strength of the fiber cement boards of the examples and comparative examples, when the bending strength of the comparative example is 100, the bending strength of the example is 107, and the bending strength of the fiber cement board of the example is improved. However, it can be seen that the reinforcing fibers are uniformly dispersed.

[Effects of the Invention] As described above, the present invention provides a papermaking bat to which a cement slurry containing cement as a main component is supplied, and a fiber in which the cement slurry is mixed with a reinforcing fiber made of vinylon fiber having a fiber length of 6 to 15 mm. Place the papermaking vat to which the cement slurry has been supplied, make up the cement slurry and the fiber cement slurry in the papermaking cylinder, transfer them onto the felt as a wet mat, wind them around the making roll, and then make the green sheet into the making roll. Since it is cut out from the green sheet and then the green sheet is cured, even a long fiber length of about 6 to 15 mm can be uniformly dispersed, and it becomes possible to use a reinforcing fiber having a long fiber length. The bending strength of the board can be increased, and this fiber cement board can be used as a roofing material. Can be advantageously prevented from even stepping cracking occurs when you.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a manufacturing method of an embodiment of the present invention,
2 is a cross-sectional view of the main part of the wet mat obtained by the same as above, FIG. 3 is a cross-sectional view of the main part of the fiber cement board obtained by the same as above, FIG. 4 is a schematic explanatory view of a conventional example, and FIG. FIG. 6 is a cross-sectional view of a main part of the fiber cement board obtained by the above, and FIG. 1 is a cement slurry, 2 and 2a, 2b, 2c are papermaking bats, 3 is a fiber cement slurry, 4 is a papermaking cylinder, 5 is a wet mat, 6 is felt, 7 is a green sheet, 12 is a making roll, A is a fiber It is a cement board.

Claims (1)

[Claims] 1. A papermaking bat supplied with a cement slurry containing cement as a main component, and a papermaking bat supplied with a fiber cement slurry prepared by mixing the cement slurry with reinforcing fibers made of vinylon fibers having a fiber length of 6 to 15 mm. And a cement layer formed by cement slurry and a fiber reinforcement layer formed by the fiber cement slurry by making the cement slurry and the fiber cement slurry by the paper making cylinder arranged in these paper making bats, respectively. Is transferred to the felt as a wet mat in a laminated state, and then multiple windings of this wet mat are wrapped around a making roll, and then a green sheet in which multiple layers of the wet mat are laminated is cut out from the making roll, and this green sheet is then cut. Fibers characterized by curing Method of manufacturing the instrument plate.