JPS6238320B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an asbestos cement board and a method for manufacturing the same, and more particularly to a multi-layered asbestos cement board and a method for manufacturing the same. As shown in FIG. 1, a conventional asbestos-cement board is made by rolling up a slurry 4 whose main components are cement and asbestos using a wire mesh roll 13, and then transferring it onto an endless paper-making belt 6 such as felt. The asbestos cement layer 1 is formed by stacking the asbestos cement layer 1 on the outer periphery of the making roll 7 in 3 to 6 layers and winding it up, and then the laminate is cut out. In the manufactured asbestos cement board, as shown in Figure 2b, each asbestos cement layer 1
Since the fibers of asbestos 3 contained in the asbestos 3 are oriented in one direction perpendicular to the thickness direction, that is, in a direction parallel to the interface between the layers, the bonding force between each asbestos cement layer 1 is weak and freezing may occur. When used in the environment, there is a problem in that delamination occurs due to stress associated with expansion and contraction that occurs during repeated freezing and melting. The present invention has been made in view of the above points, and its main purpose is to create a multilayer structure that has a strong bonding force between each asbestos cement layer and that does not cause delamination even when subjected to frost damage. An object of the present invention is to provide an asbestos cement board and a method for manufacturing the same. The present invention will be described in detail below based on embodiments shown in the figures.
As shown in FIG. 4, the asbestos-cement board according to the present invention has an asbestos-cement layer mainly composed of cement and asbestos, and the fiber direction of the asbestos 3 contained therein is perpendicular to the thickness direction of the layer. a first asbestos-cement layer 1 oriented in the direction; and a second asbestos-cement layer 2, which is an asbestos-cement layer mainly composed of cement and asbestos, and in which the fiber direction of asbestos 3 contained therein is irregularly oriented. As shown in FIG. The paper is made and transferred onto the paper making belt 6.
While forming a first asbestos-cement layer 1 in which the fiber direction of asbestos 3 is oriented in one direction perpendicular to the thickness direction, a slurry 5 containing water mixed with cement and asbestos is applied to the first asbestos-cement layer on a papermaking belt 6. A second asbestos-cement layer 2 in which the fiber direction of asbestos 3 is irregularly oriented is formed on the first asbestos-cement layer 1 by spraying on the asbestos-cement layer 1, and the first asbestos-cement layer 1 and the second asbestos-cement layer 2 are successively formed. In this embodiment, as shown in the figure,
The laminate 8 of the first asbestos cement layer 1 and the second asbestos cement layer 2 laminated on the papermaking belt 6 is wound around the making roll 7 several times, and then the laminate 8 is wrapped around the making roll 7 several times.
Cut out the asbestos cement layer 1 to an appropriate length.
2 shows an example of obtaining an asbestos cement board in which a large number of layers are alternately laminated. As the papermaking belt 6, an endless belt made of felt is used.
0 and the pinch roll 11, and is rotated along the direction of the arrow in the figure. This papermaking belt 6
A plurality of tanks 12 each storing slurry 4 are disposed below, and a wire mesh roll 13 is driven to rotate in one direction within each tank 11 while the papermaking belt 6 passes above each tank 12. The slurry 4 which has been rolled up by the wire mesh roll 13 is transferred onto the papermaking belt 6 by being transferred to the papermaking belt 6, and the first asbestos cement layer 1 is attached to the papermaking belt 6. Next, the papermaking belt 6 passes through the feed roll 10 to form the first asbestos cement layer 1.
When the asbestos cement layer 1 reaches the top, a slurry 5 having the same composition as the slurry 4 in the tank 12 is sprayed onto the first asbestos cement layer 1 by the spray device 15 to form a second asbestos cement layer 2 on the first asbestos cement layer 1. is,
After dehydrating both the asbestos cement layers 1 and 2 using the suction device 16, the asbestos cement layers 1 and 2 are rolled up in a laminated state on a making roll 7 having a diameter of about 2 m and paired with the pinch roll 11. After the start of winding, the making roll 7 rotates five times to wind up a laminate 8 in which five asbestos cement layers 1 and 2 are alternately laminated on the outer periphery of the making roll 7, and after cutting out the laminate 8. An asbestos cement board with a multilayer structure is obtained by pressing and curing, and the thickness of the first asbestos cement layer 1 and the second asbestos cement layer 2 are 0.7 to 1.0 mm and 0.1 to 0.3 mm, respectively.
Set to mm. The following table shows the conditions and results when a freeze damage test (DIN52104, freeze-thaw test method) was conducted on each asbestos cement board in order to compare the asbestos cement board according to the present invention with a conventional asbestos cement board.

[Table] As is clear from the above test results, in the asbestos cement board of the present invention, as shown in FIG. 4b, the second asbestos cement layer 2 is laminated on the first asbestos cement layer 1. Since the fibers of the asbestos 3 inside are arranged in irregular directions, the boundary with the first asbestos cement layer 1, where the asbestos 3 inside is arranged in one direction perpendicular to the thickness direction, is formed by papermaking. A part of the irregularly oriented asbestos in the second asbestos cement enters the first asbestos cement layer 1 and serves to bond the first asbestos cement layer 1 and the second asbestos cement layer 2, Therefore, both asbestos-cement boards 1 and 2 are firmly connected by the asbestos oriented in the thickness direction existing at the interface between them, and as a result, in an environment subject to freezing damage, expansion and contraction due to freezing and thawing occurs. Even if stress such as
This has the advantage that delamination can be prevented from occurring. In addition, when forming the second asbestos cement layer 2, which is the top layer of the asbestos cement board, if the slurry 5 to which pigment has been added in advance is sprayed onto the first asbestos cement layer 1, the surface of the asbestos cement board obtained The color can be finished with makeup.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a conventional method for producing an asbestos cement board, Figs.
The figure is a schematic diagram showing a method for manufacturing an asbestos cement board according to an embodiment of the present invention, FIGS. 1 is an asbestos cement layer, 2 is a second asbestos cement layer, 3 is asbestos, 4 and 5 are slurry, and 6 is a papermaking belt.

Claims (1)

[Scope of Claims] 1. A first asbestos cement layer containing cement and asbestos as main components, in which the fiber direction of asbestos contained therein is oriented in one direction perpendicular to the thickness direction of the layer; , an asbestos cement layer comprising cement and asbestos as the main components, and a second asbestos cement layer in which the asbestos fibers contained therein are irregularly oriented are alternately laminated. Board. 2. A slurry containing water mixed with cement and asbestos is made and transferred onto a paper-making belt to form a first asbestos-cement layer on the paper-making belt in which the asbestos fiber direction is oriented in one direction perpendicular to the thickness direction. A slurry containing cement, asbestos, and water is sprayed onto the first asbestos-cement layer on the papermaking belt to form a second asbestos-cement layer in which the asbestos fibers are irregularly oriented.
A method for producing an asbestos cement board, which comprises forming an asbestos cement board on an asbestos cement layer, and sequentially stacking a first asbestos cement layer and a second asbestos cement layer alternately.