JP2016020289A - Porous article and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a porous article having an excellent surface antifouling property and a method for producing the same.SOLUTION: There is provided a porous article 1 in which a plurality of pores 2 (2a and 2b) having different pore sizes each other are formed on a principal surface 1a of a tile base material 1A composed of an inorganic material. A first material 3, which is a mixture containing aluminum oxide particles and lithium silicate, is filled in the pores 2a having a large pore size. The principal surface 1a is coated with a coating film 5 containing zirconium and a hydrate compound of potassium silicate. A second material 4 containing the hydrate compound is filled in pores 2b having a small pore size.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a porous article and a method for producing the same.

As the tile, one that has been subjected to glaze treatment is usually used. Since the tile subjected to the glaze treatment has a glaze layer, it is difficult for dirt to enter the tile.
In recent years, tiles that have not been subjected to glaze treatment (glazed tiles) have been used. Glaze tiles have a different surface texture than glaze tiles and are widely used.
Glazed tiles, especially porcelain ones, are fired at high temperatures and have a very low water absorption rate, but dirt substances may enter the pores between the particles.
In the case of polishing a glaze tile for improving the texture, pores are more likely to appear on the surface, and the problem of contamination becomes serious.
As shown in Non-Patent Document 1, an unglazed tile usually has a large range of pore sizes, for example, a large number of pores having a pore size of 0.001 μm to 10 μm.
In order to prevent the stain-free tile from being stained, it is required to seal a large number of holes having such a wide range of hole diameters.

As an anti-glare tile stain prevention technique, for example, there is a technique described in Patent Document 1. In this technique, a solvent-based silicone resin is applied to the tile surface to seal the pores.
In addition, as a dirt prevention technique, there is a technique in which a water-repellent material such as a silicone resin or a fluororesin is infiltrated into the pores to prevent entry of dirt by a water-repellent action.
However, these techniques have not been sufficient as a measure against stains on glazeless tiles.
For example, in the technique described in Patent Document 1, even though micropores (for example, pore diameters of less than 1 μm) can be sealed, for pores with large pore diameters (for example, pore diameters of 1 μm or more), the treatment agent shrinks due to solvent drying. Complete sealing becomes difficult.
Also, with the water repellent coating technique, the water repellent is not filled into the micropores, so that it is difficult to prevent the soil when pressure is applied or when it is in contact with the soil for a long time.
The pore size distribution of the glaze tile ranges from 0.001 μm to 10 μm, and there are also macroscopic pores that can be confirmed with the naked eye, and seals a large number of pores having such a wide range of pore sizes. It was difficult.
On the other hand, the size of the contaminants that enter the pores varies. For example, when an unglazed tile is used as a flooring material, dirt substances include mud adhering to shoes and red wine spilled on the floor. Mud has a large particle size (for example, a particle size of several μm), and pigments contained in red wine have a small particle size (for example, a particle size of several nm). Therefore, it is necessary to deal with soiled substances having a wide range of particle sizes. .

JP 2002-336768 A

Amoros et.al ”Evolution of pore-size distribution during the firing of stoneware floor tile.” Castellon, Qualicer 96, p.737-739.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the porous article which sealed the hole of the wide hole diameter range, and improved the antifouling performance, and its manufacturing method.

As a result of investigations to solve the above problems, the present inventors have filled some of the plurality of pores with a mixture containing aluminum oxide particles and lithium silicate, and the other pores are filled with zirconium and silicate. It has been found that by filling a potassium hydrated compound, contamination in a wide particle size range can be prevented, and the present invention has been completed.
That is, the present invention relates to a porous article in which a plurality of pores having different pore diameters are formed on at least one main surface of a base material made of an inorganic material, and aluminum oxide is formed in a part of the plurality of pores. A mixture containing particles and lithium silicate is filled, and the main surface is coated with a coating containing a hydrated compound of zirconium and potassium silicate, and at least a part of the pores other than the pores filled with the mixture, A porous article filled with the hydrated compound is provided.

  The present invention is a first mixed liquid comprising an inorganic material, wherein at least one main surface of a base material on which a plurality of pores having different pore sizes are formed includes aluminum oxide particles, lithium silicate, and water. A first step of filling a part of the plurality of pores with the first mixed liquid, and a second step of removing the excess first mixed liquid that has not been filled in the pores. And by applying a second mixed solution, which is an aqueous solution containing a zirconium compound and potassium silicate, to the main surface from which the excess first mixed solution has been removed, fine particles other than pores filled with the mixture. A third step of filling at least a part of the hole with the second mixed liquid and forming a film containing a hydrated compound of zirconium and potassium silicate derived from the second mixed liquid on the main surface; Of porous articles having To provide a method.

According to the porous article of the present invention, a part of the pores is filled with a mixture containing aluminum oxide particles and lithium silicate, and the other pores are filled with a hydrated compound of zirconium and potassium silicate. Therefore, pores with a wide pore diameter range can be sealed.
For this reason, it is possible to prevent not only dirt due to coarse particles such as mud but also dirt due to fine particles such as pigments such as red wine. Therefore, a porous article excellent in antifouling performance can be obtained.

According to the method for manufacturing a porous article of the present invention, pores having a large pore diameter are sealed by application of the first mixed liquid, and pores having a small pore diameter that cannot be sealed with the first mixed liquid are converted into the second mixed liquid. It can seal by application | coating.
For this reason, pores in a wide pore diameter range can be reliably sealed. Therefore, a porous article excellent in antifouling performance can be obtained.
Moreover, according to this manufacturing method, since the porous article can be manufactured at room temperature or slightly heated, the manufacturing cost can be reduced.

It is sectional drawing which shows typically one Embodiment of the porous article of this invention. It is sectional drawing which shows typically the pore with a comparatively large hole diameter. It is sectional drawing which shows typically the pore with a comparatively small hole diameter. It is process drawing explaining one Embodiment of the manufacturing method of the porous article of this invention. It is process drawing following a previous figure. It is process drawing following a previous figure. It is process drawing following a previous figure.

The form for implementing the porous article of this invention and its manufacturing method is demonstrated.
The following embodiments are specifically described for better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified.

[Porous articles]
1 to 3 show an unglazed tile 1 which is an embodiment of the porous article of the present invention. A glaze tile is a tile whose surface has not been subjected to a glaze treatment.
The glaze tile 1 has a large number of pores 2 having a wide pore diameter (for example, several nm to several hundred μm) formed on the surface (at least the main surface 1a) of the tile substrate 1A (base material) made of an inorganic material. ing.
The glaze tile 1 is formed in a plate shape, for example, as shown in FIG. There is no restriction | limiting in particular in the planar view shape of the glaze-free tile 1, For example, it is good as a rectangle, circular, an indeterminate form. The tile base material 1A is made of, for example, ceramic.

The pore 2 is a hole formed from the main surface 1a of the tile base material 1A toward the inside. FIG. 1 shows an unglazed tile 1 in which two types of pores 2 having different pore diameters (opening diameters), that is, a plurality of large pores 2a and a plurality of fine pores 2b having a smaller average pore diameter are formed. Is illustrated.
As shown in FIG. 2, the large pore 2a is, for example, a pore 2 having an average pore diameter of 1 μm or more. As shown in FIG. 3, the micropore 2b is, for example, a pore 2 having an average pore diameter of less than 1 μm.
The average pore diameter of the pores 2 is a representative diameter that is an average of the maximum diameter and the minimum diameter for 100 or more pores 2 randomly selected based on a plan photograph of the main surface 1a of the glaze tile 1. It can calculate and can obtain | require as an average value of these representative diameters.

In FIG. 1, the six materials 2 are filled with the second material 4, but only a part of the six pores 2 may be filled with the second material 4.
Further, the main surface 1a of the tile base material 1A only needs to have two or more pores 2 having different pore diameters. For example, three or more types of pores 2 having different pore diameters may be formed.
In the example shown in FIG. 1, the pores 2 exist only on the main surface 1a of the tile base material 1A, but the pores 2 may be formed on the entire surface of the tile base material 1A.
Examples of porous articles include not only tiles but also concrete and stone.

At least a part of the large pores 2a is filled with a first material 3 that is a mixture containing aluminum oxide particles and lithium silicate. In the example shown in FIG. 1, the first material 3 is filled in the entire internal space in all four large pores 2a.
The first material 3 may be filled in all of the plurality of large pores 2a, or may be filled only in a part of the large pores 2a.
The internal space of the large pore 2a may be filled with not only the first material 3 but also the second material 4, but the ratio (mass ratio) between the first material 3 and the second material 4 is It is preferable that the amount of the first material 3 is larger (preferably the first material 3 exceeds 50% by mass).

As the aluminum oxide particles, α-type aluminum oxide particles having a corundum structure, so-called corundum particles are preferable.
Corundum particles exhibit excellent durability against both acid and alkali as well as water.

The D50 value of the particle size distribution of the corundum particles is preferably 0.5 μm or more and 5 μm or less, and the D90 value is preferably 3 μm or more, more preferably, the D50 value is 0.8 μm or more and 3 μm or less, and the D90 value is 5 μm or more. .
The D50 value is the particle diameter when the cumulative number integrated from the lower limit value of the particle size of the particle size distribution is 50% of the total number, and the D90 value is 90% of the total number integrated from the lower limit value of the particle diameter. % Is the particle diameter.
The particle size distribution of the corundum particles can be measured using a light transmission type particle size distribution measuring apparatus.

The reason why the particle size distribution of the corundum particles is in the above range is as follows.
When the D50 value is less than 0.5 μm, the viscosity of the coating liquid containing the corundum particles (first mixed liquid 3a described later) becomes difficult to apply, and when a large amount of water is added to facilitate application, When the coating film is dried, the shrinkage is large, and there is a possibility that the coating film is pierced or cracked. On the other hand, when the D50 value exceeds 5 μm, the corundum particles are not sufficiently filled into the large pores 2a, and the antifouling effect may not be sufficiently exhibited.

The reason why the D90 value is 3 μm or more is that when the D90 value is less than 3 μm, the particle size distribution becomes very narrow and the filling efficiency is lowered. In order to perform efficient filling, a wider particle size distribution is preferable.
Further, the reason why the upper limit was not set for the D90 value is that, even if coarse particles containing 10% of the total number are included, if the remaining particles are fine, there is no problem in filling, This is because the 10% coarse particles can be removed in the second step described later.

As the lithium silicate, a compound containing silicon oxide (SiO ₂ ) and lithium oxide (Li ₂ O) in a predetermined ratio, for example, a molar ratio of silicon oxide (SiO ₂ ) and lithium oxide (Li ₂ O) (SiO ₂ ) ₂ / Li ₂ O) is preferably used in the range of 3.5 to 7.5.
Lithium silicate is preferably used in an aqueous solution containing about 20% by mass of lithium silicate in terms of silicon oxide (SiO ₂ ), rather than in powder form, in terms of stability and ease of handling.
Examples of alkali silicate include sodium silicate and potassium silicate in addition to lithium silicate, but sodium silicate and potassium silicate are not preferable because they have water resistance problems and may impair practicality.

  Moreover, it is difficult to fill the aluminum oxide particles into the fine holes 2b (for example, the hole diameter is less than 1 μm). It is considered that fine aluminum oxide particles may be used for sealing the fine holes 2b. However, when such particles are used, the water ratio of the first mixed liquid 3a must be increased. Accompanying this, the drying shrinkage rate increases, and sufficient filling becomes difficult.

On the main surface 1a of the tile substrate 1A, a coating 5 made of a second material 4 containing a hydrated compound of zirconium and potassium silicate is formed.
The thickness of the coating 5 can be 1 μm or more. By setting the thickness within this range, it is possible to prevent the occurrence of interference colors in the coating 5.
The thickness of the film 5 can be, for example, 10 μm or less. By making the thickness within this range, cracking of the coating 5 can be prevented.

The second material 4 constituting the coating 5 is filled in at least a part of the fine holes 2b.
In order to fill the micropores 2b with the second material 4, a second mixed solution 4a (see FIG. 7) containing a zirconium compound and potassium silicate is applied to the main surface 1a of the tile substrate 1A. A method of allowing the mixed solution 4a to permeate the micropores 2b can be employed.

In the example shown in FIG. 1, the second material 4 is filled in the entire internal space in all of the six micro holes 2 b.
Note that the second material 4 may be filled not in all of the plurality of micro holes 2b but only in a part of the plurality of micro holes 2b.
In addition, the internal space of the fine hole 2b may be filled with not only the second material 4 but also the first material 3, but the ratio (mass ratio) between the first material 3 and the second material 4 is It is preferable that the amount of the two materials 4 is larger (preferably the second material 4 exceeds 50% by mass).

  As the zirconium compound, a zirconium salt is preferable, and zirconium carbonate alkali is particularly preferable from the viewpoint of permeability to the micropores 2b. Examples of the zirconium carbonate alkali include potassium zirconium carbonate and ammonium zirconium carbonate.

The potassium silicate constituting the second material 4 is a compound containing silicon oxide (SiO ₂ ) and potassium oxide (K ₂ O) in a predetermined ratio, for example, silicon oxide (SiO ₂ ) and potassium oxide (K ₂ O). ) Is preferably used in a molar ratio (SiO ₂ / K ₂ O) of 2 to 5 (preferably 2 to 4).
Examples of the alkali silicate include sodium silicate and lithium silicate in addition to potassium silicate, but whitening of the glaze tile 1 can be prevented and the glaze of the glaze tile 1 can be improved over a long period of time. It is preferable to use potassium silicate.

  If the coating 5 does not contain either zirconium or silicate, there is a possibility that a problem may occur in the water resistance of the glazeless tile 1.

[Method for producing porous article]
An embodiment of the method for producing a porous article of the present invention will be described in detail.
The manufacturing method of this embodiment has the 1st-3rd process.
The first step is made of an inorganic material, and is a first mixture containing aluminum oxide particles, lithium silicate, and water on the main surface of a base material on which at least one main surface is formed with a plurality of pores having different pore diameters. In this step, the first mixed liquid is filled in some of the plurality of pores by applying the liquid.
A 2nd process is a process of removing the excess 1st liquid mixture with which the pore was not filled.
In the third step, the mixture was filled by applying the second mixed liquid, which is an aqueous solution containing a zirconium compound and potassium silicate, to the main surface of the substrate from which the excess first mixed liquid was removed. At least a part of the pores other than the pores is filled with the second mixed liquid, and a film containing a hydrated compound of zirconium and potassium silicate derived from the second mixed liquid is formed on the main surface of the substrate. It is a process.
Hereinafter, each step will be described with specific examples.

"First step"
As shown in FIGS. 4 and 5, in this step, the first mixed liquid 3a containing aluminum oxide particles, lithium silicate, and water is applied to the main surface 1a of the tile substrate 1A, and the large pores 2a ( For example, it is a step of filling the first mixed solution 3a into a pore diameter of 1 μm or more.
In the manufacturing method of the present embodiment, before applying the first mixed liquid 3a, the main surface 1a (surface to be applied) of the tile base material 1A is previously cleaned and cleaned using water, an organic solvent, or the like. It is preferable to leave. Thereby, the wettability of the 1st liquid mixture 3a with respect to the main surface 1a of 1 A of tile base materials at the time of apply | coating the 1st liquid mixture 3a can be improved.

The ratio (mass ratio) of aluminum oxide particles, lithium silicate, and water in the first mixed liquid 3a is preferably 40 to 60: 1 to 10:30 to 59. The ratio is more preferably 45 to 55: 2 to 8:37 to 53.
Here, the reason why the ratio between the aluminum oxide particles and the lithium silicate is in the above range is that this range is excellent in preventing the surface of the tile base material 1A from being soiled, and the sedimentation separation between the aluminum oxide particles and the liquid is small and excellent. This is because one material 3 can be stably obtained.

The reason why the ratio (mass ratio) of aluminum oxide particles (for example, corundum particles) is 40 to 60 is as follows.
If the ratio of the aluminum oxide particles is less than 40, the opening of the first material 3 in the large pores 2a during drying becomes large, and the first material 3 is not sufficiently filled in the large pores 2a. On the other hand, when the ratio exceeds 60, the fluidity of the first mixed solution 3a becomes poor, and the first mixed solution 3a does not sufficiently penetrate into the large pores 2a.
By setting the ratio of the aluminum oxide particles in the above range, the first mixed liquid 3a can be sufficiently permeated into the large pores 2a, and the large pores 2a can be sufficiently filled with the first material 3 and sealed.

The reason why the ratio (mass ratio) of lithium silicate is 1 to 10 is as follows.
If the ratio of lithium silicate is less than 1, sufficient water resistance of the first material 3 cannot be obtained. On the other hand, if the ratio exceeds 10, the excess first mixture that has not penetrated into the large pores 2a. The liquid 3a dries and hardens, making it difficult to remove.
By making the ratio of lithium silicate into the said range, while improving the water resistance of the 1st material 3, it can make it easy to remove the excess 1st liquid mixture 3a.

The reason for setting the water ratio (mass ratio) to 30 to 59 is as follows.
When the ratio of water is less than 30, the fluidity of the first mixed liquid 3a becomes poor, and the first mixed liquid 3a does not sufficiently penetrate into the large pores 2a. Opening at the time of drying in the first material 3 in the pore 2a becomes large, and the first material 3 is not sufficiently filled in the large pore 2a.
By setting the ratio of water in the above range, the first mixed solution 3a can sufficiently penetrate into the large pores 2a, and the large pores 2a can be sufficiently filled with the first material 3 and sealed.

Although it will not specifically limit as a mixing method used when preparing the 1st liquid mixture 3a, if it is a method which can mix an aluminum oxide particle, lithium silicate, and water, For example, a ball mill, various stirrers, a mixer The mixing method by etc. is used.
In this mixing, in order to sufficiently disperse the aluminum oxide particles throughout the first mixed liquid 3a and to improve the wettability of the first mixed liquid 3a with respect to the main surface 1a of the tile substrate 1A, a surfactant is used. Etc. may be added as appropriate.
The method of applying the first mixed solution 3a is not particularly limited as long as it is a method that can reliably fill the first mixed solution 3a into the pores. For example, the application method using a roller, a brush, a brush, or a spatula An application method using an instrument such as is used.

In the example shown in FIG. 5, the first mixed liquid 3a is applied to the entire region (or a partial region) of the main surface 1a of the tile base material 1A. A part of the first mixed liquid 3a applied to the main surface 1a of the tile substrate 1A is introduced into the large pores 2a.
The 1st liquid mixture 3a in the large pore 2a becomes the 1st material 3 by drying. The first material 3 is a mixture containing aluminum oxide particles and lithium silicate.
Since the 1st liquid mixture 3a contains an aluminum oxide particle, the shrinkage | contraction when the 1st liquid mixture 3a dries is small, and it is hard to produce a hole and a crack. For this reason, the large pore 2a is reliably sealed.
Since the first mixed solution 3a contains aluminum oxide particles, it may be difficult to fill the fine holes 2b. In the example shown in FIG. 5, the first mixed liquid 3a is hardly filled in the fine holes 2b.

"Second step"
As shown in FIG. 6, this process removes the excess 1st liquid mixture 3a which did not osmose | permeate the large pore 2a among the 1st liquid mixture 3a apply | coated to the main surface 1a of 1 A of tile base materials. It is a process.
Examples of a method for removing the excess first mixed solution 3a include a method of wiping with a cloth material having water absorption, a method of rubbing with a brush or the like, and a method of sucking.

"Third process"
As shown in FIG. 7, in this step, the second mixed solution 4a, which is an aqueous solution containing a zirconium compound and potassium silicate, is applied to the main surface 1a of the tile substrate 1A from which the excess first mixed solution 3a has been removed. This is a step of applying and filling the fine pores 2b (for example, with a pore diameter of less than 1 μm) with the second mixed liquid 4a and forming the coating 5 on the main surface 1a of the tile substrate 1A. The coating 5 contains a hydrated compound of zirconium and potassium silicate.

The aqueous solution easily penetrates into the micropores 2b. The reaction rate of the hydration reaction, which is a chemical reaction between zirconium and potassium silicate, is relatively low. For this reason, the hydration reaction proceeds after the second mixed solution 4a, which is an aqueous solution, enters the micropores 2b, thereby generating a hydrated compound that does not dissolve in water in the micropores 2b. When the second mixed solution 4a is dried, the filling of the fine holes 2b is completed.
An organic compound such as a surfactant or an organic solvent may be added to the second mixed solution 4a as long as the characteristics of the coating film 5 are not deteriorated.

The second mixed solution 4a is preferably an aqueous solution containing a zirconium compound in an amount of 0.01% by mass to 1% by mass in terms of zirconium oxide and potassium silicate in an amount of 10% by mass to 30% by mass in terms of silicon dioxide.
The mass ratio of each component is preferably ZrO ₂ : SiO ₂ = 1: 10 to 1: 3000 in terms of oxide.
As the zirconium compound, potassium zirconium carbonate is preferred.

When the concentration of the zirconium compound (concentration in terms of zirconium oxide) is less than 0.01% by mass, the water resistance of the coating 5 becomes low, and when the concentration exceeds 1% by mass, the viscosity of the second mixed solution 4a increases. There is a possibility that it is difficult to apply the second mixed liquid 4a to the main surface 1a of the tile base material 1A.
By setting the concentration of the zirconium compound in the above range, the water resistance of the coating 5 can be increased, and the second mixed solution 4a can be easily applied to the main surface 1a of the tile substrate 1A.

If the concentration of potassium silicate (in terms of silicon dioxide) is less than 10% by mass, interference color in the coating 5 is likely to occur, and the commercial value of the glazeless tile 1 may be affected. Further, when the concentration exceeds 30% by mass, the coating liquid (second mixed liquid 4a) is easily dried, so that it is difficult to apply the second mixed liquid 4a to the main surface 1a of the tile substrate 1A.
By making the concentration of potassium silicate within the above range, it is possible to make it difficult for interference color to occur in the coating 5 and to easily apply the second mixed liquid 4a to the main surface 1a of the tile substrate 1A.
Moreover, in order to improve the wettability of the 1st liquid mixture 3a with respect to the main surface 1a of 1 A of tile base materials, you may add surfactant etc. which were mentioned above to the 2nd liquid mixture 4a suitably.

  The aqueous solution containing potassium zirconium carbonate and potassium silicate is prepared by, for example, diluting an aqueous solution containing about 20% by mass of commercially available zirconium potassium carbonate in terms of zirconium oxide with water using a stirring mixer or the like. It can be prepared by adding 0.01% by mass or more and 1% by mass or less in terms of zirconium oxide.

In the example shown in FIG. 7, the second mixed liquid 4a is applied to the entire area (or a partial area) of the main surface 1a of the tile base 1A, and the second mixed liquid 4a is applied to the main surface 1a of the tile base 1A. A layer is formed.
A part of the second mixed liquid 4a applied to the main surface 1a of the tile base 1A penetrates into the fine holes 2b.
An insoluble hydrated compound is generated in the micropores 2b by a chemical reaction (hydration reaction) between the zirconium compound contained in the second mixed solution 4a that has penetrated into the micropores 2b and potassium silicate.
This hydrated compound is considered to be, for example, zirconium silicate hydrate, and is excellent in terms of water resistance.

The layer of the 2nd liquid mixture 4a becomes the film 5 which consists of the 2nd material 4 by drying. Also in the film 5, an insoluble hydrated compound (for example, zirconium silicate hydrate) is generated by the same chemical reaction (hydration reaction).
The 2nd liquid mixture 4a in the micropore 2b becomes the 2nd material 4 by drying.

In order to sufficiently advance the chemical reaction (hydration reaction) between the aforementioned zirconium compound and potassium silicate, it is preferably left at room temperature (25 ° C.) for about 3 days or more. More preferably, using a heater, the chemical reaction is promoted by heating to 50 ° C to 100 ° C.
Thereby, the glaze tile 1 shown in FIG. 1 is obtained.

In the glaze tile 1 of the present embodiment, the large pore 2a among the plurality of pores 2 is filled with the first material 3 containing aluminum oxide particles and lithium silicate, and zirconium and potassium silicate are filled in the micropore 2b. A second material 4 containing a hydrated compound is filled.
Since the first material 3 contains aluminum oxide particles, the shrinkage when dried is small, and it is difficult for holes and cracks to occur. For this reason, the large pore 2a with a large pore diameter can be reliably sealed.
In addition, the fine holes 2b having a small pore diameter that could not be sealed with the first material 3 can be sealed with a hydrated compound of zirconium and potassium silicate.
In this way, since the pores 2 having a wide pore diameter range can be sealed, for example, not only dirt due to coarse particles such as mud, but also fine particles such as pigments contained in red wine, coffee, cola, etc. It is possible to prevent contamination by particles.
In particular, since red wine contains alcohol, it has a property of easily penetrating into the pores 2, but the sealing of the pores 2 can surely prevent contamination by red wine.
Therefore, the glaze-free tile 1 having excellent antifouling performance can be obtained.

The manufacturing method of the glaze tile 1 according to the present embodiment includes the step of filling the large pores 2a with the first mixed solution 3a by applying the first mixed solution 3a and the second mixed solution 4a. And forming a film 5 containing a hydrated compound of zirconium and potassium silicate.
According to this manufacturing method, the large pore 2a having a large pore diameter is sealed with the first mixed liquid 3a, and the small pore diameter 2b that cannot be sealed with the first mixed liquid 3a is sealed with the second mixed liquid 4a. can do.
In this way, since the pores 2 having a wide pore diameter range can be sealed, for example, not only dirt due to coarse particles such as mud, but also fine particles such as pigments contained in red wine, coffee, cola, etc. It is possible to prevent contamination by particles.
Therefore, the glaze-free tile 1 having excellent antifouling performance can be obtained.
Moreover, according to this manufacturing method, since the glaze tile 1 can be manufactured at normal temperature or slight heating, the manufacturing cost can be reduced.

Hereinafter, the present invention will be described more specifically by experimental examples. Note that the present invention is not limited to the following experimental examples.
As shown in FIG. 4, a Spanish glazeless porcelain polished tile was prepared as a tile base material 1A.
Muddy water (most of the soil particles have a particle size of 1 μm or more) and red wine (most of the pigment particles have a particle size of less than 1 μm) were dropped onto the main surface 1a of the tile base material 1A and allowed to dry naturally for 1 day.
The dirt adhering to the main surface 1a of the tile substrate 1A was cleaned with a brush using a detergent or an organic solvent, but dirt of mud and red wine remained as a stain.
From this, it was estimated that this tile base material 1A had pores having a pore diameter of 1 μm or more and pores having a pore diameter of less than 1 μm.

<Influence of first step and second step>
(Experimental Example 1 to Experimental Example 10)
A first mixed solution 3a having the composition shown in Table 1 was prepared. Corundum particles (D50 = 1 μm, D90 = 10 μm, manufactured by Nippon Light Metal Co., Ltd.) were used as the aluminum oxide particles. As the lithium silicate, lithium silicate 45 (manufactured by Nippon Chemical Co., Ltd.) was used.

The surface (main surface 1a) of the tile substrate 1A was washed with water and naturally dried.
As shown in FIGS. 4 and 5, the first mixed solution 3a was applied to the main surface 1a of the tile substrate 1A using a roller.
Next, as shown in FIG. 6, the excess first mixed solution 3a was removed with a rubber spatula, and the main surface 1a of the tile base material 1A was naturally dried.

<Confirmation of effectiveness of processing in first step and second step>
About the tile base material 1A which passed through the 1st process and the 2nd process, the effectiveness of processing was checked.
Muddy water (most of the soil particles had a particle diameter of 1 μm or more) was dropped onto the main surface 1a of the tile substrate 1A, and the soil particles were attached to the tile substrate 1A by natural drying for 1 day.
With respect to the dirt adhering to the main surface 1a of the tile substrate 1A, cleaning was attempted with a brush using a detergent or an organic solvent. The main surface 1a of the tile base material 1A was observed, and the degree of cleanliness was evaluated as “mud dirt cleaning property” in the following five stages. A score of 3 or higher was accepted. The results are shown in Table 2.
For comparison, the evaluation results when the first step and the second step are not performed (Experimental Example 1) are also shown in Table 2.

1: Cleanliness when the treatment by the first step and the second step is not performed (untreated).
2: Slightly better than untreated.
3: Although it is clearly better than untreated, residual dirt is observed.
4: Almost no dirt is observed.
5: Dirt is not recognized at all.

The effectiveness of the treatment in the first step and the second step was also confirmed for stains caused by red wine (most of the pigment particles were less than 1 μm in particle size).
Pigment particles are applied to the main surface 1a of the tile base material 1A by dropping red wine on the main surface 1a of the tile base material 1A that has undergone the first step and the second step, and dropping it naturally for one day. Attempted cleaning against this dirt.
The cleanliness of the main surface 1a of the cleaned tile base material 1A was evaluated as the “cleaning property for red wine stains” in the above-mentioned five stages. The results are also shown in Table 2.

From the results of Table 2, the ratio of aluminum oxide particles, lithium silicate, and water in the first mixed solution 4a was muddy due to aluminum oxide particles: lithium silicate: water = 40-60: 1-10: 30-59. It has been found that it is suitable for improving the cleanability.
Moreover, about the red wine dirt cleaning property, all the experimental examples were insufficient.

<Corundum particle size>
As shown in FIGS. 4 and 5, the first mixed solution 3a of Experimental Example 4 was applied to the main surface 1a of the tile base material 1A using a roller.
As shown in FIG. 6, the excess 1st liquid mixture 3a was removed with the rubber spatula, and the main surface 1a of the tile base material 1A was naturally dried.
As the corundum particles of the first mixed liquid 3a, those having a particle size distribution shown in Table 3 were used.
About 1 A of tile base materials, the mud dirt cleaning property was evaluated by the above-mentioned method.

  From the results in Table 3, it was found that the particle size distribution of the aluminum oxide particles preferably had a D50 value of 0.5 μm or more and 5 μm or less and a D90 value of 3 μm or more.

<Influence of the third step>
(Experimental Examples 11 to 32)
The treatments in the first step and the second step are not effective for wine stains having a small particle size, even though the cleaning properties of the mud stain having a large particle size can be improved.
It can be presumed that this is because the first mixed solution 3a could not fill fine pores of less than 1 μm into which wine pigment particles can penetrate. In order to solve this problem, a third step of sealing fine pores is necessary.

The surface (main surface 1a) of the tile substrate 1A was washed with water and naturally dried.
As shown in FIGS. 4 and 5, the roller is used to apply the first mixed solution 3a used in Experimental Example 4 to the main surface 1a of the tile base material 1A, and as shown in FIG. 1 liquid mixture 3a was removed using the rubber spatula, and the surface of tile base material 1A was air-dried.
Next, as shown in FIG. 7, the second mixed liquid 4a containing a zirconium compound, a potassium silicate compound, and water was applied to the main surface 1a of the tile base material 1A using a roller.
As the zirconium compound, potassium zirconium carbonate (manufactured by Mel Chemical Co.) was used. As the potassium silicate compound, potassium silicate (molar ratio (SiO ₂ / K ₂ O) = 3.6, manufactured by Nippon Chemical Co., Ltd.) was used. Table 4 shows the composition of the second mixed solution 4a.
The tile base material 1A to which the second mixed solution 4a was applied was left to stand at room temperature for 7 days to be naturally dried.

<Confirmation of effectiveness of processing in third step>
About the tile base material 1A which passed the 3rd process, the effectiveness of the process was confirmed.
Red wine was dropped on the main surface 1a of the tile substrate 1A, and the particles were allowed to adhere to the tile substrate 1A by natural drying for 1 day, and cleaning with a neutral detergent was attempted for this dirt.
The degree of cleanliness of the cleaned main surface 1a was evaluated as the “red wine stain cleaning property” in the above-mentioned five stages. The results are shown in Table 5.

The effectiveness of the third process was also confirmed for dirt caused by muddy water (most of the soil particles have a particle diameter of 1 μm or more).
Instead of red wine, muddy water is dropped on the main surface 1a of the tile base material 1A that has undergone the third step, and naturally dried for one day, thereby attaching soil particles to the tile base material 1A. The cleaning was attempted.
The cleanliness of the main surface 1a of the cleaned tile base material 1A was evaluated as “mud dirt cleaning property” in the following five stages. A score of 3 or higher was accepted. The results are also shown in Table 5.
For comparison, a test similar to Experimental Example 18 was performed (Experimental Example 32) except that the first step and the second step were not performed. The results are also shown in Table 5.

1: Cleanliness when the treatment in the third step is not performed (untreated).
2: Slightly better than untreated.
3: Although it is clearly better than untreated, residual dirt is observed.
4: Almost no dirt is observed.
5: Dirt is not recognized at all.

From the results in Table 5, when the ratio of potassium zirconium carbonate was less than 0.01% by mass, the coating film was easily dissolved in water. On the other hand, when the ratio of potassium potassium carbonate exceeds 1% by mass, the coating solution (second mixed solution) gelated during coating, and the coating operation became difficult.
Moreover, when the ratio of potassium silicate is less than 10% by mass, an interference color is generated in the coating 5, which affects the aesthetics of the glazeless tile 1. On the other hand, when the ratio of potassium silicate exceeds 30% by mass, the coating solution dries during coating, and the coating operation becomes difficult.
In Experimental Example 32 in which the first and second steps were not performed, good cleaning performance was not exhibited even for wine.

  Since the porous article of the present invention is filled with a mixture containing aluminum oxide particles and lithium silicate in a part of the pores, and hydrated compound of zirconium and potassium silicate is filled in the other pores, It is possible to seal pores in a wide pore diameter range. For this reason, it is possible to prevent not only dirt due to coarse particles such as mud but also dirt due to fine particles such as pigments contained in red wine or the like. Therefore, a porous article excellent in antifouling performance can be obtained. Therefore, the porous article of the present invention can be applied to various fields where surface antifouling performance is required, and its industrial value is extremely large.

DESCRIPTION OF SYMBOLS 1 ... Glazeless tile (porous article), 1A ... Tile base material (base material), 2a ... Large pore (pore), 2b ... Fine pore (pore), 3 ... First material (mixture), 3a ... 1st liquid mixture, 4a ... 2nd liquid mixture, 5 ... film.

Claims (9)

A porous article in which a plurality of pores having different pore diameters are formed on at least one principal surface of a base material made of an inorganic material,
A part of the plurality of pores is filled with a mixture containing aluminum oxide particles and lithium silicate,
The main surface is coated with a film containing a hydrated compound of zirconium and potassium silicate,
A porous article, wherein the hydrated compound is filled in at least a part of pores other than the pores filled with the mixture.   The porous article according to claim 1, wherein an average pore diameter of the pores filled with the hydrated compound is smaller than an average pore diameter of the pores filled with the mixture.   The porous article according to claim 2, wherein an average pore diameter of the pores filled with the hydrated compound is less than 1 µm, and an average pore diameter of the pores filled with the mixture is 1 µm or more.   The porous article according to any one of claims 1 to 3, wherein the thickness of the coating is 1 µm or more. Applying a first mixed liquid containing aluminum oxide particles, lithium silicate, and water to the main surface of the substrate made of an inorganic material and having a plurality of pores having different pore diameters formed on at least one main surface. A first step of filling a part of the plurality of pores with the first mixed liquid;
A second step of removing excess first mixed liquid not filled in the pores;
By applying a second mixed solution, which is an aqueous solution containing a zirconium compound and potassium silicate, to the main surface from which the excess first mixed solution has been removed, pores other than the pores filled with the mixture are formed. A third step of filling at least a portion with the second mixed liquid and forming a film containing a hydrated compound of zirconium and potassium silicate derived from the second mixed liquid on the main surface; A method for producing a porous article, comprising:   The method for producing a porous article according to claim 5, wherein ammonium zirconium carbonate or potassium zirconium carbonate is used as the zirconium compound.   The mass ratio of the aluminum oxide particles, lithium silicate, and water in the first mixed solution is aluminum oxide particles: lithium silicate: water = 40-60: 1-10: 30-59. Or the manufacturing method of the porous article of 6.   The D50 value of the particle size distribution of the aluminum oxide particles is 0.5 µm or more and 5 µm or less, and the D90 value is 3 µm or more, The porous article according to any one of claims 5 to 7, Production method. The first mixed solution contains zirconium in an amount of 0.01% by mass to 1% by mass in terms of zirconium oxide, and contains silicic acid in an amount of 10% by mass to 30% by mass in terms of silicon dioxide,
Mass ratio of the said zirconium silicate _{is, ZrO 2: SiO 2 = 1} : 10~1: production method of a porous article according to any one of claims 5-8, characterized in that it is 3000.

Images