JPS632427Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a cement board mainly used as a building material.

Cement boards, which have been commonly used in the past, are made by applying paint to the surface of a cement substrate containing asbestos, glass, etc., but over time, the alkali in the cement substrate dissolves onto the surface and whitens. It often caused a surface discoloration phenomenon called hanana, which spoiled its aesthetic appearance.

The purpose of this invention is to provide a cement board that does not cause such efflorescence.

To explain this invention based on the drawings, as shown in FIG. 1, an embodiment of the invention is shown, the cement board according to this invention has granulated blast furnace slag as its main component on the outside of a substrate 1 whose main component is cement. It is characterized by being made of a cured product having an outer layer 2 that is
In addition to cement, the substrate 1 usually contains reinforcing asbestos, glass fiber, organic fibers (for example, fibers of pulp, polyvinyl formal, nylon, polyester, etc.), and the outer layer 2
In addition to granulated blast furnace slag, a small amount of asbestos is usually added for the same purpose. The outer layer may also contain a small amount of pigment for coloring, such as red iron. One or more paint layers 3 are provided on the surface of the outer layer 2, if necessary. In this way, if an outer layer mainly composed of granulated blast furnace slag is provided on the outside of a substrate mainly composed of cement, the alkali coming out from the cement of the substrate will be absorbed into the outer layer mainly composed of granulated blast furnace slag. This prevents it from eluting to the surface of the cement board. Therefore, it is possible to prevent the surface from turning white, ie, efflorescence, which occurs in conventional cement boards. The thickness of the substrate is generally 4 to 10 mm, and the thickness of the outer layer is 0.05 to 10 mm.
It is preferably 2.0 mm, and more preferably 0.1 to 0.3 mm. The paint layer on the surface is applied to make the cement board waterproof, to help suppress efflorescence, and to enhance the aesthetic appearance of the cement board.Usually, a synthetic resin liquid such as water-based acrylic resin emulsion is used. applied.

Next, an example of this invention will be described.

〔Example〕

First, a substrate having the following composition was manufactured by papermaking. Hereinafter, "part" refers to part by weight.

Cement: 70 parts Asbestos: 15 parts Organic fiber (pulp): 2 parts After spraying a slurry mixed with water and having the following composition other than water on the outer surface of this substrate, the entire surface is mixed with approximately 80 kg in a direction perpendicular to the surface. Pressure was applied for about 10 seconds at a pressure of /cm ² .

Granulated blast furnace slag (powder) 100 parts Asbestos 4 parts Pigment (red iron) 3 parts As a result, the entire substrate was dehydrated, and an outer layer mainly composed of granulated blast furnace slag was formed on the outer surface of the substrate. The thickness of the substrate was approximately 7 mm, and the thickness of the outer layer was approximately 0.2 mm. After applying a water-based acrylic resin emulsion (manufactured by Dainippon Ink & Chemicals Co., Ltd., trade name Boncoat 835) to the surface of the cement board manufactured in this way, it was placed in an atmosphere with a relative humidity of approximately 90% and a temperature of approximately 70°C.
It was exposed for 10 hours and then allowed to cure naturally for 3 weeks to harden. Finally, the surface was painted with enamel to obtain a beautiful cement board. The structure of this cement board is shown in Figure 2. In FIG. 2, 1 is a substrate, 2 is an outer layer, 3a is a paint layer made of water-based acrylic resin emulsion, and 3b is an enamel paint layer. This cement board did not develop efflorescence even after a long period of time, and the surface remained beautiful.

The composition of the substrate is 50 to 90 parts of cement, 10 to 20 parts of asbestos, 0 to 3 parts of organic fiber, and 0 to 40 parts of granulated blast furnace slag. Similarly excellent cement plates were obtained by selecting a composition containing 2 to 6 parts of asbestos and 0 to 7 parts of pigment per 100 parts of granulated blast furnace slag.

As explained above, the cement board according to this invention has an outer layer mainly composed of granulated blast furnace slag on the outside of the substrate mainly composed of cement, so that the efflorescence phenomenon does not occur even after a long period of time. This prevents this from happening and keeps the surface in a beautiful condition.
It is an excellent building material. Moreover, since a paint layer serving as a decorative layer is provided on the surface of the main body constructed in this way, this paint layer blocks carbon dioxide gas in the air and more effectively prevents the occurrence of efflorescence. do.

[Brief explanation of the drawing]

1 and 2 are sectional views showing an embodiment of this invention. 1...Substrate, 2...Outer layer, 3...Paint layer.

Claims (1)

[Scope of utility model registration request] 1. A cement board comprising a cured material having an outer layer mainly composed of granulated blast furnace slag on the outside of a substrate mainly composed of cement, and having a paint layer on the surface of this material.