JPH0146479B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for forming a colored pattern on the surface of an inorganic board mainly made of asbestos, cement, etc. Conventionally, the method of forming a colored layer on the surface of an inorganic board mainly made of asbestos, cement, etc. is to apply a coloring agent such as a pigment onto an uncured or hardened raw board made by a paper making machine. A method has been adopted in which a single colored layer is attached by coating or spraying, but in this case, the coloring agent is simply attached to the surface of the substrate, so cracks may occur in the colored layer during the subsequent processing steps. In addition, there were drawbacks such as the substrate and colored layer of the product peeling off due to shrinkage and expansion due to frost damage and the like. The present invention improves these conventional drawbacks and is capable of producing a so-called "natural stone pattern" that is not simply surface coloring, and will be described in detail below. In the process of manufacturing an inorganic board by paper-making a mixed slurry mainly composed of inorganic materials such as asbestos and cement, the present invention is applied at a point when the substrate formed on the felt has a moisture content of 40 to 70% and is still fluid. in,
A colored slurry mainly made of the same material as the substrate and prepared by adding desired colorants, additives, etc., is sprayed onto the substrate (raw original plate) at a spray pressure (gauge pressure) of 0.5 to 5 kg/ ^cm2. After application, the colored pattern formed on the substrate surface is fixed by suctioning and dehydrating excess water, thereby achieving the above-mentioned objects of the present invention. be. In the present invention, instead of simply coating or scattering a coloring agent onto the raw original plate formed on felt, a colored slurry of the same type as the substrate is sprayed under pressure, so that the colored slurry is mixed with the upper layer of the raw original plate. By suctioning and dehydrating this semi-mixed state, the colorant is firmly fixed on the substrate, and there is not only no risk of peeling, but also a natural color that cannot be obtained by simply applying or spraying. It is possible to produce a stone pattern, but in order to do so, it is important to appropriately select the moisture content of the raw plate formed on the felt and the spraying pressure of the colored slurry.As a result of various experiments, It has been found that good results can be obtained when the colored slurry is sprayed at a spray pressure (gauge pressure) of about 0.5 to 5 Kg/cm ² when the moisture content of the raw plate is in the range of about 40 to 70%. It is something. A typical example of the substrate in the present invention is a so-called asbestos-cement board, but ordinary Portland cement, white Portland cement, and other hydraulic cements are used as the cement, and gypsum may be appropriately mixed therein. It goes without saying that other than asbestos, rock wool, glass fiber, organic fiber, etc. can be used as appropriate. The colored slurry is prepared by adding desired colorants (various inorganic/organic pigments, etc.), additives (waterproofing agents, anti-cracking agents, e.g. silica sand, calcium carbonate), etc. to a material of the same type as the substrate. be. Embodiments of the present invention will be described with reference to the drawings.
The figure is a schematic diagram of an apparatus for making asbestos/cement boards, where A shows two slurry tanks, 1 shows asbestos/cement slurry, 2 feels for papermaking, and 3 shows a raw original board formed on the felt. 7 sprays the colored slurry at a predetermined pressure onto the raw original plate 3 that has reached a predetermined thickness and moisture content using a spray device, and then suctions and dehydrates excess water using a suction box 8 to remove the colored layer from the raw original plate. fixed on top. The raw original plate on which the colored pattern has been formed is wound around a making roll 4, and pressed by the roll to further firmly fix the colored pattern and make the surface smooth. (not shown) is cut into a predetermined size and sent onto the belt conveyor 5.
6 is an asbestos/cement board with a colored pattern cut to a predetermined size and transferred to a curing room to become a product. Example of composition of substrate slurry and colored slurry (weight ratio)
is shown below.

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【table】 [Brief explanation of drawings]

The figure is a schematic diagram of a papermaking apparatus, in which 1 is a slurry tank, 2 is a felt for papermaking, 4 is a making roll, 7 is a spray device, and 8 is a suction box.

Claims (1)

[Claims] 1. In the process of manufacturing an inorganic board by paper-making a mixed slurry mainly composed of inorganic materials such as asbestos and cement, when the substrate formed on the felt has a moisture content of 40 to 70% and is still fluid, On the substrate, a colored slurry prepared by adding desired colorants, additives, etc. to the same material as the substrate is sprayed at a spray pressure (gauge pressure) of 0.5 to 5 Kg/ ^cm2 .
1. A method for forming a colored pattern on the surface of an inorganic board, which comprises fixing the colored pattern formed on the surface of the substrate by suctioning and dehydrating excess water.