JP2020127906A - Substrate and manufacturing method thereof - Google Patents

Abstract

To provide a base material which can maintain a clean appearance even without being frequently cleaned, in order to solve a problem that base materials such as a wall and a floor of a building, stone materials which are used as a garden stone, a gravestone, a stone fence, a stone image, an art object, a stone monument, a road and a paving stone, glass and metals have a water absorbing property, that while the base materials are used, mold, moss, algae, various bacteria and other stains erode the surface and adhere thereto, and that even if the base material is washed, the stains infiltrate into the base material and cannot be removed in some cases, which thereby has required much labor and cost for the cleaning.SOLUTION: There is provided the base material that has a surface coated with a coating agent which contains a photocatalytic material and an organic binder, and which makes the surface water-repellent, and that has an excellent self-cleaning function of repelling water and decomposing stains by a decomposition action of the photocatalyst.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to an antifouling technique for a base material such as a wall, a floor, a garden stone, a tombstone, a stone statue, a monument, an object, a road, a paving stone and the like used for a building, glass, metal, etc.

In the above-mentioned base material, the surface is water-absorbing, absorbs rainwater and moisture, and if used outdoors for a long time, mold, moss, algae, various bacteria, and other stains may erode the surface and adhere. is there. As a result, even if it is washed, it cannot be removed because it is soaked. Even when it is used indoors, even if it has no nutrients, only moisture or water adheres to the surface, and mold, moss, algae, and other bacteria grow and become dirty. As a result, due to these causes, mold, moss, and algae grow on the surface of the base material, which impairs the aesthetics.Each time, the surface of the base material is cleaned with scrubbing brush, sponge, mop, high-pressure cleaning, etc. It was carried out, and it took a lot of trouble and cost.

On the other hand, a base material or material processed with a photocatalyst has been used in recent years, and the decomposition action of the photocatalyst is trying to decompose mold, moss, algae, various bacteria, etc. to prevent dirt (see Patent Document).

JP, 2000-256079, A JP, 2002-234107, A JP, 2002-242486, A JP, 2002-338374, A JP, 2004-238817, A JP, 2005-087908, A JP, 2006-239490, A JP, 2007-075704, A JP, 2008-043831, A

However, since the photocatalyst is usually superhydrophilic, the surface of the substrate on which the photocatalyst is processed becomes hydrophilic, and moisture and moisture adhere to the surface, so molds and moss, Algae and other bacteria propagate and become contaminated. Then, once the surface of the base material is contaminated, light is blocked by the dirt and the photocatalyst on the surface of the base material is not exposed to light, and the effect of the photocatalyst cannot be exerted. Therefore, mold, moss, algae, various bacteria, etc. We couldn't prevent the dirt from breeding.

Therefore, it was tried to apply a water-repellent coating on the surface of the base material and then apply a photocatalyst to it, but the photocatalyst decomposes the water-repellent coating, which immediately becomes hydrophilic and can be used in a short period of time. It was gone. Therefore, a substrate excellent in antifouling function obtained by coating the substrate with a water-repellent photocatalytic film has not been found in the market until now. An object of the present invention is to eliminate this weak point of the photocatalyst, which has been a problem for a long time, and to provide an epoch-making substrate excellent in antifouling function.

In the present invention, in order to solve the above problems, a coating material containing a photocatalyst material and an organic binder is coated on the surface of the substrate, and the coated surface has a water-repellent substrate. provide.

For example, in the first aspect, the surface is coated with a coating agent containing a photocatalytic material and an organic binder, and the coated surface is water repellent.

Further, in this case, as in the second aspect, the photocatalytic material is preferably particles having a particle diameter of 80 nm or less.

Further, in the above aspect, the following third to fifth aspects may be adopted.

In the third aspect, the photocatalytic material is one in which an inorganic material is partially supported on the surface of metal oxide or metal oxide particles. In a fourth aspect, the metal oxide is selected from one or more of titanium oxide, tungsten oxide, zinc oxide, lead oxide, tin oxide, antimony oxide, indium oxide, indium tin oxide, and tin oxide-antimony oxide. It will be.

In the fifth aspect, the inorganic substance is at least one selected from apatite, silica, and alumina.

Moreover, in the said 1st-5th aspect, you may make it like the following 6th aspect.

In a sixth aspect, the organic binder is made of any one or more of organic silicate, alkali metal organic silicate, silicon resin, and fluororesin.

Moreover, in the said 1st-6th aspect, you may make it like the following 7th aspect.

In a seventh aspect, the coating agent further contains a solvent, and the photocatalytic material in the solid content is 0.01% by weight to 10% by weight.

Moreover, in the said 1st-7th aspect, you may make it like the following 8th aspect.

In the eighth aspect, the content of the organic binder with respect to the photocatalyst material in the coating agent is 0.1 or more and 100 or less in terms of weight.

Further, as in the case of the ninth aspect, if it is a manufacturing method including a step of allowing a coating agent containing a photocatalytic material and an organic binder to permeate the surface of the substrate, the same substrate as in each of the above aspects is manufactured. can do.

Similarly, as in the tenth aspect, as long as it is a manufacturing method including a step of infiltrating a coating agent containing a photocatalyst material and an organic binder into the surface of a substrate, and a step of heating and drying, each of the above Substrates similar to those in aspects can be manufactured.

According to the present invention, a water-repellent photocatalytic film, particularly a transparent water-repellent photocatalytic film, is formed on the surface of a substrate. As a result, the surface of the substrate repels water and the water does not soak in, preventing rainwater from seeping into the substrate and changing its color to a wet color and preventing mold, moss, algae and other bacteria from growing. It has various effects such as preventing corrosion by acid rain, preventing the water that has soaked in the winter from freezing and cracking the base material, and preventing salt damage. It also has the effect of preventing icing and icicles. Moreover, since the photocatalyst is attached to the surface of the base material, the photocatalytic decomposition action cleans the dirt adhering to the surface of the base material by oxidizing and decomposing it into water and carbon dioxide, thus providing a synergistic effect of self-cleaning. .. Furthermore, the photocatalyst can decompose bacteria, viruses, and malodors that come in contact with the surface of the substrate, so that antibacterial and deodorizing effects can be obtained at the same time.

The base material is a gravestone made of natural granite or marble whose surface is mirror-polished, for example, granite or marble paving stones cut into about 40 cm squares, lanterns, garden stones, stone monuments, buildings, ruins, etc. Various natural stones, artificial stones, and other stone materials, concrete materials, mortar materials, bricks, tiles, roof tiles, and tiles can be used. It is possible to treat not only newly cut and manufactured substrates, but also substrates that have been installed for several decades.

The water repellency of the surface of the substrate coated with the coating agent containing the photocatalyst material and the organic binder according to the present invention is determined by measuring the contact angle between the substrate surface and the water droplet by dropping a water droplet on the surface of the substrate. It can be measured, but the contact angle with water is preferably 90 degrees or more and 180 degrees or less, and particularly preferably 110 to 180 degrees. If the water contact angle of the wall of the base material is 90 degrees or more, it becomes difficult for water to adhere, and if it is 110 degrees or more, even if water is applied to the surface of the base material, water drops will roll off and become wet.

The organic binder used in the coating agent containing the photocatalyst material according to the present invention is preferably water-repellent when dried, and is also preferably durable against the decomposition action by the photocatalyst. Examples of such materials include organic silicates, organic silicates of alkali metals, silicone resins, and fluororesins. Typical organic silicates are alkyl silicates such as methyl silicate and ethyl silicate, and when dried, a water-repellent organic silica film is formed. Alkali metal organic silicates are typified by alkyl silicates such as sodium methyl silicate, potassium methyl silicate, lithium ethyl silicate, and potassium propyl silicate, and when dried, become a water-repellent organic silicate film. These films and films made of silicon resin or fluororesin are water repellent and have durability against the decomposition action by the photocatalyst.

The photocatalyst material used in the coating agent containing the photocatalyst material according to the present invention is a metal such as titanium oxide, tungsten oxide, zinc oxide, lead oxide, tin oxide, antimony oxide, indium oxide, indium tin oxide, tin oxide-antimony oxide. Although it is an oxide, when a base material coated with a coating agent containing a photocatalyst material and an organic binder is used for a long period of time, the organic content in the water-repellent film formed on the surface of the base material is gradually increased. Is decomposed by the photocatalyst and the water repellency gradually decreases, so it is desirable to use those in which the inorganic substances are partially supported on the surface of the metal oxide particles. In that case, since the contact between the metal oxide particles as the photocatalyst and the organic matter in the water repellent film is prevented by the inorganic substance, the decomposition of the organic matter is prevented and the water repellency of the substrate surface is maintained, It can be used for a long time.

As the photocatalyst material used in the coating agent containing the photocatalyst material according to the present invention, it is desirable to use a photocatalyst material having a particle size such that light scattering can be suppressed. For example, it is considered that ultrafine particles having a particle size of 80 nm or less are used. To be In this case, light scattering is suppressed, and a transparent coating agent or coating film can be obtained. As the concentration of the photocatalyst material added to the coating agent, the solid content of the photocatalyst material is 0.01% to 10% as a concentration that can maintain the oxidative differentiation ability as the photocatalyst while preventing whitening due to aggregation of the photocatalyst particles. Is desirable.

The coating agent containing the photocatalyst material according to the present invention preferably has a concentration ratio of photocatalyst material and organic binder of photocatalyst material:organic binder=1:0.1 or more and 100 or more. This concentration ratio is defined as a concentration ratio that can maintain the performance as a photocatalyst as well as the adhesion and durability as an organic binder.

The coating agent containing the photocatalyst material according to the present invention further contains a solvent in the photocatalyst material and the organic binder, and water can be used as the solvent. The substrate surface is porous, hydrophilic and water-absorbent. Therefore, if the solvent is water, the coating agent containing the photocatalyst material has an affinity with the substrate, so that the coating agent easily penetrates into the surface of the substrate and is easily coated. In addition, water is safe, non-toxic, inexpensive and easy to handle.

Regarding processing into a base material, it is better not only to apply the solution of the coating agent containing the photocatalyst material to the surface of the base material to be the base material but also to permeate the inside of the surface. By applying the coating agent to the inside of the surface, permeating it and drying it, a water-repellent film with a structure like a Kenzan made of organic groups is coated on the porous and uneven surface of the base material. Is further increased, and a water-repellent film having excellent durability can be obtained. Then, the permeation makes the inside of the substrate water-repellent, prevents the invasion of mold, moss, algae, various bacteria and the like, and forms an antifouling layer which has a long-lasting effect.

Regarding processing into a base material, a solution of a coating agent containing a photocatalyst material may be permeated into the surface and inside the surface due to the porosity of the base material, and then heated and dried at a temperature of 200°C or lower. preferable. By heating after coating, an antifouling water repellent layer having excellent durability is formed in a short time. At a high temperature of 200° C. or higher, depending on the base material, there are some that may be denatured by releasing crystal water or the like, so the heating temperature is preferably 200° C. or lower.

Further, regarding processing into a substrate, a solution of a coating agent containing a photocatalyst material may be applied to the surface of the substrate which has been heated to a temperature of 30° C. or higher and 200° C. or lower in advance. When pre-heated, the liquid that has permeated from the surface of the base material is immediately hardened, and a highly durable antifouling layer can be formed in a short time.

Further, regarding processing into a base material, a solution of a coating agent containing a photocatalyst material is applied to the surface of the base material which has been heated to a temperature of 30° C. or higher and 200° C. or lower in advance, and further heated and dried at a temperature of 200° C. or lower. Is especially desirable. By doing so, a highly durable antifouling layer can be formed.

Example 1 A coating solution was prepared by dispersing 1% of titanium oxide sol (Jupiter F4APS manufactured by Showa Denko KK) having apatite partially supported on the surface of particles, 10% of potassium ethyl silicate and 0.1% of indium oxide in water. .. Immerse this coating liquid in a rag, wipe the surface of the outer wall of the concrete covered with green mold with one side of the university building in Bangkok, Thailand, wipe off the mold cleanly and coat the inside of the concrete outer wall Permeated. Since the outside air temperature was 40° C., the coating liquid dried in one day and a water repellent film was formed. Initially, the outer surface of the concrete was gray because the roots of the mold remained, but the photocatalyst decomposed the roots of the mold, and it became pure white over time. And, after 3 years, it was still in good condition. On the other hand, the part that was not wiped off with the coating solution remained covered with green mold after 3 years.

Example 2 0.1% of titanium oxide powder (Jupiter S manufactured by Showa Denko KK) having silica partially supported on the particle surface, 5% of silicone resin emulsion, and 0.05% of indium tin oxide were dispersed in water. A coating liquid was prepared. Immerse this coating solution in a sponge, wipe the black granite tombstone 5 years after installation to clean the surface, and allow the coating solution to penetrate into the surface of the tombstone, so that the surface temperature becomes 50°C. Then, the surface of the tombstone was dried by using an electric heater to form a water-repellent film. When the water contact angle on this surface was measured, it was 145 degrees and it fell down even if a water drop was dripped. When this tombstone was left as it was for one year, even after one year, there was no attachment of mold and moss, and the tombstone remained in a clean state.

Comparative Example 1 A tombstone that had been installed for 5 years was washed and cleaned. When this was left as it was in the actual environment, about 1 week in summer and 2 months in winter, green molds and moss were seen to breed and the tombstone was contaminated.

Example 3 Titanium oxide powder (Jupiter F4AP manufactured by Showa Denko KK) 5% partially supporting apatite on the particle surface, sodium ethyl silicate 20%, and tin oxide-antimony oxide 0.1% were dispersed in water for coating. A liquid was prepared. Next, the surface of a new marble plate having a size of 40 cm square and a thickness of 2 cm was impregnated with the coating liquid while being coated with a roll coater. Then, it was heated and dried using an electric heater so that the surface temperature of the marble was 60°C. As a result, the surface of the marble became water-repellent and did not penetrate even when water was applied. The water contact angle of this surface was measured and found to be 138 degrees. This marble plate was subjected to an accelerated deterioration test for 1,500 hours using a sunshine weatherometer. As a result, it was found that even after 1500 hours, the water contact angle was 135 degrees, the same water repellency could be maintained, and the durability was excellent.

Example 4 3% of titanium oxide powder (Jupiter S manufactured by Showa Denko KK) 3% partially supporting silica on the particle surface, 30% of fluororesin emulsion and 0.05% of antimony oxide were dispersed in water to form a coating solution. Prepared. Next, the garden stone (chart rock) was heated using an electric furnace so that the surface temperature was 70° C., and the garden stone was dried. The prepared coating liquid was applied to one half of the surface of the garden stone with a brush to allow it to soak. Then, the temperature was raised again in the electric furnace until the surface reached about 60°C. This was cooled to room temperature, and then the lower half was immersed in an outdoor pond to actually use it as a garden stone. One year after use, the coated side had no algae adhered in the water and the garden stone remained clean, whereas the uncoated part had algae adhered in water and in the air. It turned green.

Example 5 A coating liquid was prepared by dispersing 1% of titanium oxide powder (Jupiter S, manufactured by Showa Denko KK) 1% having partially supported silica on the particle surface, lithium methyl silicate 15% and indium oxide 0.1% in water. did. Next, the paving stone of a new concrete block was heated using an electric heater so that the surface temperature became 50°C, and the water content of the paving stone was dried. The prepared coating liquid was applied by spraying to about half of the surface of the paving stone that had reached 50° C. and allowed to soak into the surface. Then, it was again heated and dried with an electric heater until the surface reached about 100°C. This was cooled to room temperature and then used outdoors as a paving stone. After one year of use, the coated part was free of mold and moss and the paving stones remained clean, while the uncoated part turned black. It is considered that the antifouling treatment that was durable against the wear caused when a person walks on it was performed.
The above-mentioned base material may be made of a material capable of binding the above-mentioned coating agent to the surface. For example, not only stone materials but also materials such as glass, metal, resin material, and paper should be adopted. You can also

According to the present invention, there is provided a material having an excellent antifouling function as a base material of stones, glass, metal, etc. used as walls and floors of buildings, garden stones, tombstones, stone walls, stone statues, objects, stone monuments, roads, paving stones, etc. It becomes possible to use it for various purposes.

Claims (10)

A substrate whose surface is coated with a coating agent containing a photocatalytic material and an organic binder, and the coated surface is water repellent. The base material according to claim 1, wherein the photocatalytic material is particles having a particle diameter of 80 nm or less. The base material according to claim 1 or 2, wherein the photocatalyst material is a metal oxide or a material partially supporting an inorganic substance on the surface of the metal oxide particles. The said metal oxide consists of titanium oxide, tungsten oxide, zinc oxide, lead oxide, tin oxide, antimony oxide, indium oxide, indium tin oxide, and any one or more types of tin oxide-antimony oxide. Base material. The base material according to claim 3 or 4, wherein the inorganic material comprises at least one of apatite, silica, and alumina. The said organic binder is a base material in any one of Claim 1 to 5 which consists of an organic silicate, an organic silicate of an alkali metal, a silicone resin, and a fluororesin. 7. The substrate according to claim 1, wherein the coating agent further contains a solvent, and the photocatalytic material in the solid content is 0.01% by weight to 10% by weight. The substrate according to any one of claims 1 to 7, wherein the content of the organic binder in the coating agent with respect to the photocatalytic material is 0.1 or more and 100 or less in terms of weight. A method for producing a base material, which comprises a step of impregnating a surface of the base material with a coating agent containing a photocatalytic material and an organic binder. A manufacturing method comprising: a step of permeating a coating agent containing a photocatalyst material and an organic binder onto the surface of a substrate; and a step of heating and drying.