JPS61127687A - Manufacture of inorganic construction board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field 1] The present invention relates to a technique for preventing cracking and peeling of a clear layer of an inorganic building board.

[Background technology] Inorganic architectural boards have been manufactured by applying a sealer treatment to an inorganic substrate such as asbestos slate, then applying a base coat paint, and then applying a clear coat on top for a cosmetic treatment.However, UV clear etc. When a clear layer having a high solid content is applied to form a thick clear layer, there is a problem in that the clear layer cracks or peels off as the inorganic substrate expands and contracts. This problem was especially noticeable when inorganic building boards were immersed in hot water. Therefore, it could not be used as wall material in bathrooms.

[Objective of the Invention 1 The present invention was made in view of the above-mentioned circumstances, and its purpose is to form a clear layer with a large thickness by applying a clear with a high solid content such as IJV clear. To produce an inorganic building board which does not cause cracks or peeling in the clear layer even in the case of a certain condition, has excellent heat resistance, and can be particularly suitably used as a wall material for a bathroom.

[Disclosure of the Invention 1 The manufacturing method of the present invention is a method for manufacturing an inorganic architectural board in which an inorganic substrate is subjected to a sealer treatment, a base coat paint is applied, and a clear coat is applied thereon. Extender pigment 15-7
It is characterized by using a paint mixed with 5% by volume, and with this configuration, the object stated in item 1 can be achieved. In other words, since the extender pigment is mixed with the epoxy urethane paint to make the base coat paint, the epoxy urethane paint ensures heat resistance, and the extender pigment makes the surface of the base coat paint rough, resulting in good adhesion to the clear lacquer. This can prevent cracking and peeling.

As the inorganic substrate in the present invention, an asbestos slate board, a wood wool cement board, an asbestos cement perlite board, a pulp cement board, an asbestos cement calcium silicate board, etc. can be employed. First, this inorganic substrate is impregnated with a sealer such as a moisture-curable urethane resin sealer and subjected to sealing treatment. This sealer treatment is carried out by applying the sealer to the inorganic substrate by spraying, shower coater, etc., or by immersing the inorganic substrate in the sealer. In this case, the latter dipping method does not require large-scale equipment, allows arbitrary settings of conditions such as viscosity, and allows the inorganic substrate to be uniformly impregnated with the sealer. This sealer treatment improves the adhesion with the base coat paint, and then a base coat paint consisting of an epoxy urethane paint mixed with 15 to 75% by volume of an extender pigment is applied. The extender pigment roughens the coating surface of the base coat paint to improve its adhesion to the clear layer, causing the clear layer to follow dimensional changes of the inorganic substrate, thereby preventing the clear layer from cracking and peeling. In the present invention, it is essential to mix 15 to 75% by volume of an extender pigment into the epoxy urethane paint. If the extender pigment content is less than 15% by volume, the adhesion between the clear layer and the base coat paint surface will be insufficient, which may not only cause cracks but also cause the clear layer to peel off, or vice versa. This is because if it exceeds 75% by volume, the water absorption of the coating surface of the base coat paint will increase and the adhesion will decrease, resulting in cracks or peeling. A clear lacquer is applied on the coated surface of this base coat paint to form a clear layer to obtain an inorganic architectural board. In this case, since the surface of the paint film of the paste coat paint is rough, a clear lacquer with a high solids content such as UV clear is used to thicken the paint film.

Next, the present invention will be described in detail, but the present invention is not limited to the following examples.

(Example 1) An asbestos cement calcium silicate plate was used as an inorganic substrate, and 55% of one-component moisture-curing urethane sealer (Asbestos Sheets, manufactured by Nippon Paint Co., Ltd.) was applied to this inorganic substrate.
After applying 0g/m2, 100g/m2 of epoxy urethane paint containing 20% by volume of extender pigment (Himart Plaza 7, Isamu Paint) was applied, and then UV clear was applied to obtain an inorganic architectural substrate.

This inorganic building board was immersed in hot water for 3 hours, but no peeling or cracking was observed.

(Example 2) A solid construction board was obtained in the same manner as in Example 1 except that an epoxy urethane paint containing 70% by volume of extender pigment was used.

This inorganic building board was immersed in hot water for 3 hours, but no peeling or cracking was observed.

(Comparative Examples 1 to 4) Comparative Example 1) An inorganic building board was obtained in the same manner as in Example 1 except that an epoxy urethane paint containing no extender pigment was used. An inorganic architectural board was obtained in the same manner as in Example 1 except that an epoxy urethane paint containing 10% by volume of extender pigment was used (Comparative Example 2). An inorganic building board was obtained in the same manner as in Example 1 except that an epoxy urethane paint containing 80% by volume of extender pigment was used (Comparative Example 3).
. An inorganic architectural board was obtained in the same manner as in Example 1 except that an epoxy urethane paint containing 90% by volume of extender pigment was used (Comparative Example 4).

When these inorganic building boards were immersed in hot water for 3 hours in the same manner as in the Examples, the clear layer of Comparative Example 1 peeled off. In Comparative Example 2, cracks occurred at the edges of the clear layer. Even in Comparative Example 3, cracks occurred at the edges, and in Comparative Example 4, the cracks were quite large.

This is because if the extender pigment is 10% by volume, the surface of the epoxy urethane paint cannot be made rough enough to improve adhesion with the clear layer, whereas if it is more than 80% by volume, the surface of the epoxy urethane paint will absorb water. This is thought to be due to excessive sexual activity.

[Effect of the invention 1] In the present invention, since a paint containing epoxy urethane paint mixed with 15 to 75% by volume of extender pigment is used as the base coat paint, the extender pigment roughens the surface of the base coat paint, resulting in a clear lacquer. Even when a clear lacquer with a high solids content such as UV clear is applied to form a thick clear layer, the clear layer can follow the dimensional changes of the inorganic substrate. It can be used to produce inorganic construction boards that do not crack or peel, and because they use epoxy urethane paint, they have excellent heat resistance and can be used particularly as bathroom wall materials. It is.

Claims (1)

[Claims] (1) In a method for manufacturing inorganic architectural boards in which an inorganic substrate is treated with a sealer, a base coat paint is applied, and then a clear coat is applied on top of the base coat paint, 15 to 75% by volume of an extender pigment is mixed with an epoxy urethane paint as the base coat paint. 1. A method for manufacturing an inorganic architectural board, characterized by using a paint made of