JP2003128481A - Method for manufacturing stain-resistant building material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a stain-resistant building material which has a hydrophilic surface and maintains the hydrophilicity even if the surface is abrased. SOLUTION: A liquid containing silicon alcoxide and silica fine powder is made to adhere to the surface of the building material consisting of a ceramic or a metal, and thereafter the silica based hydrophilic surface is formed by exposing the surface in a hot gas such as a flame or the like in such a way that the surface temperature rises to 200-500 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an antifouling building material, and more particularly to a method for producing an antifouling building material having a hydrophilic surface having a self-cleaning function that does not easily get stains.

[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 water adheres to the surface of the base material, the water spreads on the surface of the film, and along with rainwater, dirt spreads widely on the surface of the film and runs off. As a result, the surface of the base material is less likely to be stained and is less noticeable.

A titanium oxide (TiO ₂ ) film is widely used as such a superhydrophilic film having a self-cleaning function.

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 (all 100 parts by weight in total) is applied to the surface of cement, concrete, glass, ceramics, etc.
It is described that the coating film is cured by heating at 00 ° C., thereby forming a coating film that is hydrophilic and does not easily stain.

Japanese Unexamined Patent Publication (Kokai) No. 8-290942 describes that a coating containing a hydrolyzable organic silane and colloidal silica is applied and heated to 150 ° C. to form a hard coating.

[0006]

Since the titanium oxide-based superhydrophilic coating utilizes the photocatalytic action of TiO ₂ ,
The antifouling property is not exerted at night without light.

JP-A-10-158585 and 8-2
The coating of No. 90942 has low durability and is insufficient in long-term antifouling property.

The present invention has remarkably excellent antifouling properties,
Moreover, it is an object of the present invention to provide a method for producing an antifouling building material, which can efficiently produce an antifouling building material having a hydrophilic surface with good durability.

[0009]

According to the method for producing an antifouling building material of the present invention, after a liquid containing silicon alkoxide and silica fine particles is attached to the surface of a building material made of ceramic or metal, the surface temperature is 200 to 500 ° C. Is applied to form a silica-based hydrophilic surface.

According to the method of the present invention, an antifouling building material having a hydrophilic surface can be efficiently produced in a short time. Since the produced antifouling building material is treated at a relatively high temperature of 200 to 500 ° C, the adhesion strength with the building material (base material) of the silica-based surface layer is high, and durability, especially abrasion resistance, is high. Excellent in.

In the present invention, a flame is suitable as the hot gas. Also, it is desirable to apply this flame intermittently to suppress the temperature rising rate.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a building material as a base material is preferably ceramic or metal, specifically a tile is preferable, and a glazed tile for exterior is particularly preferable.

The liquid deposited on the surface of the building material contains silicon alkoxide and silica fine particles. As the silicon alkoxide, those commercially available as silicon tetraalkoxide can be used. Specific examples include methyl silicate, ethyl silicate, propyl silicate, butyl silicate, hexyl silicate, ethyl hexyl silicate, and the like, but in consideration of various points such as availability, methyl silicate, ethyl silicate. Silicates are preferably used.

Colloidal silica is preferred as the silica fine particles. As the colloidal silica, water-dispersed acidic colloidal silica, water-dispersed alkaline colloidal silica, alcohol-dispersed colloidal silica and the like are used.

Among them, acidic colloidal silica or alcohol-dispersed colloidal silica is preferably used.

The ratio of the silicon alkoxide and the silica fine particles, a weight A obtained by converting the silicon in the silicon alkoxide in Si0 _2, the ratio A / B of the weight B of the silica fine particles 0.1
It is preferably 0.4. The mixture of silicon alkoxide and silica fine particles is preferably diluted with a diluent so that the viscosity becomes easy to handle. As the diluent, ethyl alcohol, propyl alcohol, butyl alcohol and the like are preferable.

The silicon alkoxide is preferably diluted with the same diluent as above before being mixed with the silica fine particles, and the hydrolysis catalyst and water are preferably added and mixed.

As the hydrolysis catalyst and water, an aqueous solution of hydrochloric acid is preferable, and one having a concentration of about 1 to 5% is preferable.

As a method for adhering the liquid containing silicon alkoxide and silica fine particles to the surface of the building material, spraying, coating with a coater or the like can be adopted. The adhered amount is 0.1 on the surface of the building material, which is the total silica content of the weight of silicon in the silicon alkoxide converted to SiO ₂ and the weight of the silica fine particles.
The amount is preferably about 1.0 g / m ² .

After the above liquid is adhered to the surface of the building material, it is dried if necessary, and then hot gas, preferably flame, is applied,
The silica component is baked onto the surface of the building material to make the surface of the building material a hydrophilic surface. A gas burner flame is suitable as the flame.

When the flame is continuously applied, the surface of the building material may be rapidly heated and cracked. Therefore, the flame is repeatedly applied intermittently, and the surface temperature of the building material is 200 to 200% relatively slowly.
It is preferable to raise the temperature to 500 ° C. The rate of temperature increase is preferably 50 to 600 ° C./min on average.

When the flame is intermittently applied, the burner facing the building material may be turned on and off, but when mass-producing the antifouling building material, the burner and the building material are moved relatively. Is preferred. Specifically, a building material is continuously conveyed by a heat-resistant and fire-resistant conveyor, and a plurality of burners are arranged above the conveyor at intervals in the conveying direction so that the building material passes through a region below the burner. Sometimes try to hit the flame.

According to the method of the present invention, the contact angle of water is 15 °.
The antifouling building material having the following silica-based hydrophilic surface layer can be produced. The abrasion resistance of the silica-based hydrophilic surface layer is sufficiently high, and even if the surface is rubbed with a foreign substance, the hydrophilicity is sufficiently high and the durability is excellent.

[0024]

[Example] Example 1 A silicon alkoxide solution having the following formulation was prepared. 2 parts by weight of ethyl silicate Isopropyl alcohol 8.5 parts by weight Isobutyl alcohol 2.5 parts by weight 3.5% dilute hydrochloric acid 0.5 part by weight

Isopropyl alcohol-dispersed colloidal silica (IPA-ST, manufactured by Nissan Chemical Industries, Ltd., solid content 30) was added to 13.5 parts by weight of the silicon alkoxide solution in total.
˜31 wt%) 6.5 parts by weight and 80 parts by weight of engineering isopropyl alcohol as a diluent were mixed to prepare a spray liquid. This liquid was sprayed onto the surface of a porcelain glazed exterior tile at a rate of 30 g / m ² . Then, the flame of a gas burner was applied and the temperature was raised to 350 ° C. in 60 seconds. The flame was repeatedly irradiated for 5 seconds and stopped for 10 seconds.

The water contact angle of the surface of the antifouling building material (tile) thus manufactured was measured and found to be 12 °. After rubbing the surface 5 times with a sand eraser, the water contact angle was measured and found to be 15 °.

In this case, the ratio A / B of the silica weight A derived from the silicon alkoxide and the silica weight B derived from the colloidal silica is 0.30.

Example 2 The total time of flame irradiation was 90 seconds, and the maximum temperature rise was 50
An antifouling building material (tile) was manufactured in the same manner as in Example 1 except that the temperature was 0 ° C, and the same contact angle measurement was performed. The results are shown in Table 1.

In this Example 2, it was found that it is preferable to raise the temperature to 500 ° C. or lower because some tiles were cracked.

Comparative Example 1 An antifouling building material (tile) was produced in the same manner as in Example 1 except that the flame irradiation was performed for 4 seconds and the maximum temperature rise was 150 ° C., and the same contact angle measurement was performed. It was The results are shown in Table 1.
Shown in.

Comparative Example 2 An antifouling building material (tile) was produced in the same manner as in Example 1 except that colloidal silica was not blended and the diluent (engineering isopropyl alcohol) was blended in an amount of 86.5 parts by weight. Then, the same contact angle measurement was performed. The results are shown in Table 1.

As shown in Table 1, the contact angle of water in this case is extremely large and the antifouling property is poor.

Comparative Example 3 6.5 parts by weight of colloidal silica and a diluent (isopropyl alcohol) 9 were used without adding a silicon alkoxide solution.
An antifouling building material (tile) was produced in the same manner as in Example 1 except that only a liquid containing 3.5 parts by weight was sprayed.
The same contact angle measurement was performed. The results are shown in Table 1.

As shown in Table 1, in this case, the water contact angle is significantly increased by the abrasion treatment with the sand eraser.

[0035]

[Table 1]

[0036]

As described above, according to the present invention, there is provided an antifouling building material having a hydrophilic surface and maintaining the hydrophilicity of the surface even when it is worn.

Claims (3)

[Claims] 1. A silica-based hydrophilic surface is obtained by depositing a liquid containing silicon alkoxide and silica fine particles on the surface of a building material made of ceramic or metal, and then applying hot gas so that the surface temperature is 200 to 500 ° C. A method for producing an antifouling building material, which comprises forming 2. The method for producing an antifouling building material according to claim 1, wherein the hot gas is a flame. 3. The method for producing an antifouling building material according to claim 2, wherein the flame is applied intermittently.