JP2002336769A - Method for forming antifouling layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming an antifouling layer on a surface of a coating film without non-uniformity. SOLUTION: In the method for forming the antifouling layer by coating a solution for forming the antifouling layer containing inorganic particles on a substrate or the coating film, the solution is coated at the surface temperature of 60 deg.C or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an antifouling layer, and more particularly to a method for forming an antifouling layer having a self-cleaning function which is less likely to be stained.

[0002]

2. Description of the Related Art When a superhydrophilic film is formed on the surface of a base material such as a tile, when the water adheres to the surface of the base material, the water spreads on the surface of the film, and dirt spreads widely along with the rainwater on the surface of the film and flows down. As a result, the surface of the base material is hardly stained and is less noticeable.

[0003] As a superhydrophilic film having such a self-cleaning function, a titanium oxide (TiO ₂ ) film is widely used.

JP-A-10-158585 discloses that 2.5 to 15 parts by weight of acidic colloidal silica, 0.1 to 15 parts by weight of an amine compound, and 10 to 80 parts by weight of an inorganic filler such as silica, alumina or mullite. A coating composition comprising 17 to 87 parts by weight of water or a hydrophilic organic solvent (100 parts by weight in total) on a surface of cement, concrete, glass, ceramics or the like;
It is described that the coating film is cured by heating at 00 ° C., thereby forming a coating layer which is hydrophilic and hardly adheres to dirt.

Japanese Patent Application Laid-Open No. 6-71219 discloses that a colloidal silicic acid aqueous solution is applied to a coating surface composed of a synthetic resin emulsion and a pigment to form a colloidal silicic acid film on the coating surface, thereby providing hydrophilicity and excellent stain resistance. Forming a coated layer.

[0006]

The titanium oxide superhydrophilic film utilizes the photocatalytic action of TiO ₂ ,
The antifouling property is not exhibited at night or the like when light is not applied.

JP-A-10-158585 and 6-7
The coating layer formed by applying the coating composition of No. 1219 has hydrophilicity and stain resistance.
However, when the liquid of the coating composition is applied to a smooth coating surface or a substrate surface, the adhesion of the coating layer is weak, and the coating layer is separated at an early stage.

Further, the liquid aggregates or shrinks due to the surface tension of the liquid, so that the liquid forms a spot (spot), and the antifouling layer cannot be formed uniformly on the entire surface.

As a countermeasure, a surface tension reducing agent such as ethanol may be added to the coating solution. However, the cost is increased and the working environment is deteriorated due to evaporation of the ethanol. When a large amount of ethanol is added, the colloidal silica gels and becomes unsuitable for coating.

[0010] An object of the present invention is to provide a method for forming an antifouling layer capable of uniformly forming an antifouling layer on a substrate surface or a coating film.

[0011]

According to the present invention, there is provided a method for forming an antifouling layer by applying a liquid for forming an antifouling layer to the surface of a substrate or a coating film. The method is characterized in that the liquid is applied at a surface temperature of the substrate or the coating film of 60 ° C. or higher.

As described above, when a liquid is applied to a surface having a high temperature, a solvent component such as water evaporates before the liquid agglomerates or contracts due to surface tension, so that an antifouling layer is uniformly formed on the entire surface. . The antifouling liquid is silica, alumina,
It may contain inorganic fine particles such as an aluminum magnesium composite oxide.

The liquid for forming the antifouling layer may contain colloidal silica and alumina or aluminum magnesium composite oxide.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

In the method for forming an antifouling layer according to the present invention, when a liquid for forming an antifouling layer such as a liquid containing colloidal silica is applied to the surface of a substrate or a coating film, the temperature of the applied surface is set to 60 ° C. or more. Is what you do. Examples of the substrate include building materials such as tiles and siding (before construction), housing materials such as bathtubs and washbasins, and civil engineering materials such as guardrails. Examples of the coating film include those formed on the surface of these substrates.

Examples of the coating film include coating films formed of various organic or inorganic paints such as acrylic, acrylic silicon, alkoxysilane and epoxy.

The liquid applied for forming the antifouling layer contains titanium oxide and colloidal silica, preferably colloidal silica, as components for forming the antifouling layer. The colloidal silica particles are preferably amorphous silica particles. The particle size of the silica particles is 50 nm or less, especially 25 n
m or less. Since the silica particles are hydrophilic, the antifouling layer is provided with sufficiently high hydrophilicity.

The silica particles are contained in the antifouling layer at a concentration of 50%.
% By weight (hereinafter, unless otherwise specified,% means% by weight) It is particularly preferable that 85% or more be contained in the liquid.

When the colloidal silica particles are amorphous, a large amount of OH groups are present on the surface of the particles, so that the hydrophilicity of the antifouling layer can be further enhanced.

The liquid for forming the antifouling layer may contain, as a component other than colloidal silica, an alkyl silicate, preferably ethyl silicate, or water glass as a film-forming component.
Furthermore, various additives such as fillers can be included in this liquid according to the application.

This liquid may further contain an aluminum component, specifically, an alumina / aluminum-magnesium composite oxide in a proportion of 1 to 30% by weight in the antifouling layer. By containing this aluminum component, the alkali resistance of the antifouling layer is greatly improved. The aluminum component is preferably a water-soluble aluminum compound or fine particles having a particle size of 1 μm or less, particularly 50 nm or less.

The thickness of the antifouling layer is preferably 1000 nm or less, particularly preferably 50 to 200 nm. Antifouling layer thickness is 100
If it exceeds 0 nm, peeling of the antifouling layer tends to occur. If the antifouling layer is excessively thin, it becomes difficult to form the antifouling layer on the surface of the coating film without pinholes.

In order to form an antifouling layer on the surface of a coating film, a liquid for forming an antifouling layer is applied to a substrate or a coating film surface temperature of 60 ° C. or higher. In order to perform this coating, coating using a roll coater, spin coating, spraying, curtaining, or the like can be employed.

Since the temperature of the surface to which this liquid is applied is high, the solvent component such as water in the applied liquid evaporates immediately, and a uniform spreading state can be obtained. If the surface temperature is excessively high, the antifouling component may deteriorate, so the surface temperature is preferably set to 150 ° C. or lower.

The surface temperature can be raised to 60 ° C. or higher by a method of heating the base material or, when the coating film is baked, by applying the liquid to the heated base material coming out of the heating furnace for coating film baking. May be applied. In the case of a tile or the like, the liquid may be applied to a heated base material that has come out of a firing furnace. In the case of a substrate to be subjected to steam curing or autoclave curing, a liquid may be similarly applied to the substrate coming out of the curing device.

[0026]

EXAMPLE 1 50 parts by weight of an acrylic resin emulsion (concentration 40%) and filler (calcium carbonate) 10 were coated on the surface of a 100 × 100 × 16 mm autoclaved cement extruded plate.
A mixture with 50 parts by weight of a 50% dispersion was applied at a rate of 150 g / m ² , and then heated in a heating furnace at 150 ° C. to form a coating film. After the plate was cooled, the plate was placed in a high-temperature room and heated to 100 ° C., and a liquid for forming an antifouling layer was applied in this state.

The liquid for forming the antifouling layer is a 1.12% dispersion of colloidal silica. This liquid was applied to the plate surface at a rate of 40 g / m ² by spraying.

The presence or absence of uneven coating of the antifouling layer on the surface of the thus obtained plate with an antifouling layer was evaluated by applying water to the surface and observing the repelling condition of water. As a result, it was recognized that there was no coating unevenness.

Examples 2 and 3 An antifouling layer was formed in the same manner as in Example 1 except that the surface temperature of the plate was 90 ° C. (Example 2) or 80 ° C. (Example 3). went. As a result, it was recognized that there was no coating unevenness.

Example 4 An antifouling layer was formed in the same manner as in Example 1 except that the coating amount of the antifouling layer forming liquid was 80 cc / m ² and the surface temperature of the plate was 90 ° C. An evaluation was performed. As a result, it was recognized that there was no coating unevenness.

Example 5 An experiment was performed in the same manner as in Example 2 except that the concentration of the antifouling layer forming solution was 0.56%. As a result, it was recognized that there was no coating unevenness.

Example 6 The procedure of Example 2 was repeated, except that a liquid for forming an antifouling layer was applied to a plate having a surface temperature of 90 ° C. immediately after coming out of a heating furnace for curing the coating film. An experiment was performed. As a result, it was recognized that there was no coating unevenness.

Comparative Example 1 An experiment was conducted in the same manner as in Example 1 except that the solution was applied at room temperature (21 ° C.). As a result, it was recognized that the formed liquid had unevenness.

The results are shown in Table 1. As shown in Table 1, there is no unevenness in the antifouling layer in each example. On the other hand, in Comparative Example 1 in which application was performed at normal temperature, unevenness was present in the antifouling layer.

[0035]

[Table 1]

As described above, according to the present invention, a hydrophilic antifouling layer firmly and uniformly adhered to a coating film is formed.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ikunori Hatanaka 5-1-1 Koie Honcho, Tokoname-shi, Aichi Prefecture Inax Corporation (72) Inventor Hiroshi Fukumi 5-1-1 Koie Honcho, Tokoname-shi, Aichi Stock Inax Corporation (72) Inventor Yukari Ichikawa 5-1-1 Koiehonmachi, Tokoname-shi, Aichi F-term in Inax Corporation (Reference) 4D075 BB23X CA34 DB11 DB43 DB47 DB54 DC02 DC05 EA02 EB01 EC02 EC03 EC53

Claims (3)

[Claims] 1. A method for applying a liquid for forming an antifouling layer to a surface of a substrate or a coating film to form an antifouling layer, comprising: A method for forming an antifouling layer, which is applied. 2. The method according to claim 1, wherein the surface temperature is set at 60.
To 150 [deg.] C., a method for forming an antifouling layer. 3. The method for forming an antifouling coating film according to claim 1, wherein the liquid contains inorganic fine particles such as silica, alumina, and aluminum magnesium composite oxide.