JPS5829266B2 - Method for producing calcium silicate molded bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a lightweight molded body containing hydrated calcium silicate as a main component, and its purpose is to prevent the mutual sticking phenomenon of molded bodies during a hydrothermal curing reaction. At the same time, the surface of the final product is improved to make it suitable for various cosmetic treatments.

Traditionally, these types of products, such as heat insulation materials, fireproof covering boards, and calcium silicate boards, have been made using silicic materials such as silica sand and diatomaceous earth, calcareous materials such as slaked lime and cement, and fibrous materials such as asbestos and pulp as reinforcing materials. After being dispersed in water, it is subjected to a primary reaction treatment if necessary, and then molded into various desired shapes using a press molding machine, paper making machine, etc., steam-cured in an autoclave, and finished by drying. .

In the above manufacturing process, the autoclave treatment is performed so that the molded bodies are packed as densely as possible in the autoclave so as to be in contact with each other, such as by stacking them, in order to improve throughput.

In this case, a calcium silicate crystallization reaction also occurs at the contact surface of the composite shapes, and the crystals become entangled with each other, resulting in a so-called blocking phenomenon in which the molded bodies stick to each other, and this peeling not only requires extra labor but also There were many problems such as damage to the surface of the molded product.

Therefore, to prevent this, mold release agents such as various animal and vegetable oils and synthetic resin emulsions are used, but these are all insufficiently effective, and silicone oils are used when painting the final product or applying decorative paper. In such cases, there was a drawback in preventing damage to adhesion with paints, decorative paper, etc.

The inventors of the present invention have conducted various studies in consideration of the above-mentioned problems, and have found that the blocking phenomenon in the autoclave can be almost completely prevented by applying a water-soluble alginate aqueous solution to the surface of the calcium silicate molded product after dehydration molding. In addition, they discovered that products with excellent surface properties can be obtained even during finishing processes such as painting and pasting with decorative paper.

Alginate is a hydrophilic polymer electrolyte extracted and manufactured from brown algae such as kelp and kelp, and its chemical composition is a linear polymer consisting of β-1,4 bonds of D-mannouronic acid.

It is usually commercially available as the sodium or ammonium salt.

These have the property of reacting with various metal salts to produce insoluble metal alginate.

That is, the hydrogen of the carboxyl group in the alginic acid composition is easily replaced by a metal ion.

The anti-blocking effect in the present invention is that the calcium ions present on the surface of the hydrated molded product after dehydration molding become calcium alginate and become insoluble, thereby preventing the calcium silicate crystallization reaction at the contact surface of each molded product in the autoclave. considered to be a thing.

Furthermore, the reason why the surface of the product of the present invention has excellent properties as a makeup base is that calcium silicate lightweight molded bodies generally have a structure in which calcium silicate crystals are porously aggregated.
The surface strength of the product is also weak, and the adhesive force with various cosmetic materials is poor.The surface layer of the product manufactured using the method of the present invention is reinforced with a polymeric alginate film, so it has a surface strength suitable for various cosmetic treatments. It is considered that the

As a result of numerous experiments, the amount of alginate to be applied is approximately 0.05 to 1 g per square meter of the molded body surface, and the appropriate concentration is approximately 2 to 1 CJ9/11.

Further, as for the coating method, appropriate methods such as brushing, spraying, flow coating, etc. can be adopted depending on the shape of each product.

Examples will be described below.

After dispersing 30 parts of diatomaceous earth, 15 parts of silica sand powder, 45 parts of slaked lime, and 20 parts of asbestos fiber in an appropriate amount of water, it was formed into a 6 mm thick molded plate using a paper forming machine, and the surface was coated with a concentration of 0.3.
Commercial sodium alginate water dissolution adjusted to 0.117%
/77j, and 20 sheets were stacked and placed in an autoclave for steam curing.

After curing, the cured molded plate could be peeled off extremely easily down to the lower layer.

Furthermore, after drying, a decorative paper was attached using a vinyl acetate adhesive, and after 24 hours, the adhesion of the decorative paper was measured using a cross-cut film peeling tester, and the result showed an adhesion of loo%.

At the same time, the result of measurement on a conventional molded plate without applying sodium alginate was 87%, which was poor.

Claims (1)

[Claims] 1 Calcium silicate molding characterized by dehydrating and molding a slurry in which a silicic raw material, a calcareous raw material, and a fibrous raw material are dispersed in water, applying an aqueous alginate solution to the surface of the molded body, and then performing a hydrothermal curing treatment. How the body is manufactured.