JP2000290060A - Inorganic sheet and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a ceramic sheet less liable to the deterioration of the activity of a titanium dioxide photocatalyst even after high temperature treatment and excellent in antibacterial and antifouling properties, deodorizing activity and NOx removing capability. SOLUTION: A slurry containing inorganic compound particles having 0.2-10 μm average particle diameter, having voids whose maximum diameter is <=250 nm and carrying titanium dioxide particles whose average particle diameter is 5-200 nm in the voids and a slurry not containing the inorganic compound particles are separately formed into sheetlike moldings by a sheet making process and the moldings are laminated, integrated under pressure and fired in the range of 900-1,350 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a building interior / exterior material, a laboratory tabletop, a table top, a kitchen backboard,
The present invention relates to an inorganic plate excellent in antibacterial property and antifouling property, which can be suitably used as a surface design material such as a material for a sterile room, a material for a hospital or a biochemical clean room, a material for a chemical laboratory, and a material for a bath interior.

[0002]

2. Description of the Related Art In recent years, attention has been paid to the photocatalytic action of titanium oxide, and various materials are coated with titanium oxide for the purpose of imparting antibacterial properties and antifouling properties. Also,
JP-A-8-117606 describes a multifunctional material having a photocatalytic function, which is obtained by coating a base material surface with titanium oxide, further coating a metal such as copper, and then performing a heat treatment. The photocatalytic action of titanium oxide is more remarkable as the particles are finer, that is, as the surface area is larger.However, since the particles grow by heat treatment and the photocatalytic action decreases as the surface area decreases, the heat treatment of the base material includes:
Processing is performed at a relatively low temperature of 800 ° C. or less.

[0003] However, when the base material is a ceramic such as a tile, titanium oxide particles are liable to fall off or peel off in a low-temperature treatment. It was difficult to apply.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to reduce the activity of the titanium oxide photocatalyst even when subjected to high-temperature treatment, and to improve the antibacterial and antifouling properties. An object of the present invention is to provide an excellent inorganic plate and a method for producing the same.

[0005]

According to the present invention, there is provided an inorganic compound particle having an average particle diameter in a range of 0.2 to 10 μm, wherein the inorganic compound particle has a maximum diameter of 250 nm or less. And an inorganic plate carrying titanium oxide particles having an average particle diameter in the range of 5 to 200 nm.

Here, silver, copper,
It is also preferable that at least one metal selected from the group consisting of zinc, tin and nickel or an ion thereof is supported.

Further, the inorganic compound particles have a layered structure of an inorganic layer containing inorganic compound particles having an average particle diameter in the range of 0.2 to 10 μm and an inorganic layer not containing the inorganic compound particles. The pores have a maximum diameter of 250 nm or less, and the pores have an average particle diameter of 5 to 200 nm.
The inorganic plate carrying the titanium oxide particles in the range described above is also preferable.

Further, it is preferable that the outermost layer is an inorganic layer containing the inorganic compound particles.

[0009] Further, it has pores having an average particle diameter in the range of 0.2 to 10 µm and a maximum diameter of 250 nm or less,
And, after forming a slurry containing inorganic compound particles in which the pores carry titanium oxide particles having an average particle diameter in the range of 5 to 200 nm to form a sheet-like molded body,
A method for producing an inorganic plate that is fired in the range of 00 to 1,350 ° C. can be used.

[0010] Further, there is a pore having an average particle diameter in the range of 0.2 to 10 µm and a maximum diameter of 250 nm or less, and the pore has an average particle diameter in the range of 5 to 200 nm. The slurry containing the inorganic compound particles on which the titanium oxide particles are supported, and the slurry not containing the inorganic compound particles are each formed into a sheet-like molded body, and the two types of sheet-shaped molded bodies are laminated and pressed. Then, a method for producing an inorganic plate, which is fired at a temperature in the range of 900 to 1,350 ° C. after integration, may be used.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The inorganic plate of the present invention is characterized in that it contains inorganic compound particles having an average particle diameter in the range of 0.2 to 10 μm. The inorganic compound particles have pores having a diameter of 250 nm or less, and the pores carry titanium oxide particles having an average particle diameter in the range of 5 to 200 nm. A photocatalytic function by the particles can be provided. In the present invention, by using the above-mentioned inorganic compound particles, even when a high-temperature treatment is performed, the growth of the titanium oxide particles is regulated by the pores, and the photocatalytic activity of the titanium oxide can be kept high. Further, for example, NOx can be decomposed and removed by the photocatalytic action of the titanium oxide, and furthermore, by the antibacterial action based on the photocatalytic reaction, a bad smell caused by the propagation of bacteria can be prevented.

It is preferable to use the inorganic compound particles which do not melt at the firing temperature of the ceramic material. For example, zirconium phosphate, yttria partially stabilized zirconia, and alumina zirconia can be used.

The average particle diameter of the inorganic compound particles is 0.2 to 1
Use a material within the range of 0 μm, but 0.2 to 5 μm
Is more preferable, and it is more preferable that it is in the range of 0.2 to 2 μm. When the average particle diameter is less than 0.2 μm, reagglomeration occurs and it is difficult to uniformly disperse. Further, when the slurry is formed into a sheet-like molded body, it is difficult to stay in the molded body, and loss tends to occur. Also,
If it exceeds 10 μm, it becomes difficult to obtain a sufficient surface area for supporting the titanium oxide particles. Here, the average particle diameter of the inorganic compound particles refers to a value measured by a laser diffraction particle size distribution analyzer after preparing a sample according to JIS-R-1622.

The above-mentioned inorganic compound particles have a maximum diameter of 25.
Although it has pores of 0 nm or less, it is particularly preferable to have pores having a maximum diameter of 100 nm or less. Here, the pore refers to an open pore communicating with the outside of the inorganic compound particles, and the maximum diameter is defined as an open pore having a diameter of D or less when the volume distribution of the open pore is measured by a mercury intrusion method described below. Occupies at least 80% of the total volume D
Say. (Mercury Intrusion Method) About 1 g of inorganic compound particles were put into a sample cell, and the inside of the cell was set to 1.33 × 10 ⁻¹ Pa (1.0 × 10 ⁻³ T).
orr). Next, mercury is injected, the pressure P in the cell is gradually increased to about 1.9 × 10 ⁸ Pa, and the relationship between the pressure and the mercury intrusion amount is determined using a porosimeter.
The pressure is converted to the diameter D based on the following equation.

Diameter D = -4 (σ cos θ) / P σ: Surface tension of mercury (use 0.48 N / m) θ: Contact angle of mercury with sample (use 141.3 °) The average particle diameter of the titanium oxide particles to be supported is in the range of 5 to 200 nm.
It is particularly preferred that it is in the range of 〜50 nm. If the average particle diameter is less than 5 nm, handling becomes difficult, and
If it exceeds 0 nm, it becomes difficult to obtain a sufficient surface area of titanium oxide, and the photocatalytic reaction tends to have low activity. Here, the average particle diameter of the titanium oxide particles refers to a value measured by a powder X-ray diffraction method, and is calculated using the following equation.

Average particle diameter = 0.9λ / βcos θ λ: X-ray wavelength θ: Peak position angle β: Half width The above inorganic compound particles include at least one selected from the group consisting of silver, copper, zinc, tin and nickel. It is preferable that one kind of metal or its ion is supported. By supporting the metal, the inorganic plate can be provided with antibacterial properties even in an environment where the photocatalytic reaction of titanium oxide does not easily occur, for example, in an environment where ultraviolet light having a wavelength of 400 nm or less does not reach. Among the above metals, it is preferable to use silver or silver ions which are excellent in antibacterial properties and safety.

When the inorganic plate has a layered structure of the inorganic layer containing the inorganic compound particles and the inorganic layer not containing the inorganic compound particles, the amount of the inorganic compound particles used can be reduced, which is advantageous in cost. In this case, the inorganic layer containing the inorganic compound particles is preferably the outermost layer.

Next, a method for manufacturing an inorganic plate will be described.

The inorganic plate of the present invention is obtained by forming a slurry containing the above-mentioned inorganic compound particles into a sheet-like molded body,
This is performed by firing within the range of 900 to 1,350 ° C.

As the components of the slurry, in addition to the above-mentioned inorganic compound particles, ceramic materials such as various clays, kaolin, pottery stone, silica sand, wollastonite, feldspar, dolomite, alumina, zirconia , Wollastonite, talc, fly ash, upright, and anti-firestone may be used. In addition to these components, various chemicals such as anionic organic polymer electrolytes and cationic organic Fixing agents and coagulants such as electrolytes, cationic inorganic colloids, and polyvalent metal salts,
SBR latex, pulp, asbestos fibers, glass fibers can also be added. Further, in order to improve the design of the inorganic plate, pigments, colored fine particles, natural granite fine particles, and the like can be added.

The above components are charged into water at a predetermined ratio and stirred to form a slurry for papermaking. The solid content of the slurry is preferably in the range of 0.5 to 10% by weight, more preferably in the range of 1 to 5% by weight.

Next, the slurry is formed into a sheet by using a long-mesh or round-mesh paper machine. It is preferable that the thickness of the sheet-like molded body is in the range of 0.1 to 10 mm.

Next, the above-mentioned sheet-shaped molded body is dried. Drying may be carried out by natural drying, but a roll dryer or a tunnel dryer may be used.

Next, the sheet-like molded body obtained as described above is 900
~ 1,350 ° C, more preferably 1,100
It is fired in the range of 1,200 ° C. to produce an inorganic plate. If the firing temperature is lower than 900 ° C., the strength and hardness of the inorganic plate tend to be insufficient, and the above-mentioned inorganic compound particles easily fall off. If the firing temperature exceeds 1,350 ° C., the amount of decomposition gas generated during the firing process increases,
It tends to be difficult to remove quickly and the quality of the inorganic plate tends to be unstable.

Further, the slurry containing the above-mentioned inorganic compound particles and the slurry not containing the above-mentioned inorganic compound particles are separately formed into sheet-like molded articles, and these two types of sheet-shaped molded articles are laminated.
After being pressurized and integrated, it can be fired in the range of 900 to 1,350 ° C. to produce an inorganic plate.

In this case, it is preferable to laminate a sheet-like molded product containing inorganic compound particles as the outermost layer. Each of the laminated sheet-like molded bodies is pressed and integrated by being pressed.

The pressurization may be performed, for example, using a flat press or a roll press within a linear pressure range of 100 to 500 kg / cm, preferably 100 to 300 kg / cm. When the linear pressure is lower than 100 kg / cm, the binding force between the sheet-shaped molded bodies becomes small, and peeling between the layers easily occurs in the firing step. Also, 500kg / c
If it exceeds m, the density of the sheet-like molded body becomes too large, so that the decomposition gas generated in the firing step becomes difficult to escape, and the quality may not be stable. In order to obtain a stable quality inorganic plate, the density of the sheet-like molded product is set to 1.80 to 2.
It is good to be in the range of 00, more preferably in the range of 1.82 to 1.92.

Further, it is preferable to perform heating at the same time as the above-mentioned pressurization within the range of 40 to 150 ° C., since the binding force between the sheet-like molded bodies increases.

[0029]

EXAMPLES (Example) Zirconium phosphate particles having an average particle diameter of 0.7 μm and having pores having a maximum diameter of 100 nm are immersed in a water slurry containing titanium oxide having an average particle diameter of 10 nm and dried. The titanium oxide was supported on the pores. Then, dipped in a solution containing silver nitrate and dried,
Silver ions were supported on zirconium phosphate particles.

Then, 1 part by weight of the above-mentioned zirconium phosphate particles, 2 parts by weight of black pigment, 6 parts by weight of pulp, SB
R latex 6 parts by weight, 85% by weight aplite and 1
100 parts by weight of a ceramic raw material containing 5% by weight wollastonite was mixed to form a water slurry, and the water slurry was formed into a sheet to obtain a sheet-like molded body having a thickness of about 0.7 mm. Then, a sheet-like molded body having a thickness of about 0.7 mm was obtained using a slurry not containing the above-mentioned zirconium phosphate particles and black pigment, and five such molded bodies were laminated, and the above-mentioned zirconium phosphate particles were formed on the outermost layer. The sheet-like molded articles were laminated to obtain a sheet-like laminate having a thickness of about 4.2 mm.

Then, the sheet-like laminate was heated at 60 ° C. and pressurized at a linear pressure of 200 kg / cm to be integrated.
By firing for an hour, an inorganic plate having a length of 2,400 mm, a width of 900 mm, and a thickness of 3.6 mm was manufactured.

Regarding the obtained inorganic plate, the Society for the Study of Inorganic Antibacterial Agents such as Silver, "Self-specified Standards for Inorganic Antibacterial Agents such as Silver and the Antibacterial Test Method"
The antibacterial activity was evaluated based on the antibacterial activity test method I (1995 edition) film adhesion method for antibacterial processed products. In this evaluation method, the antibacterial activity is inferior as the viable cell count at 35 ° C. for 24 hours increases compared to the viable cell count immediately after inoculation. Table 1 shows the evaluation results.

Further, an aqueous solution containing 1% by weight of methylene blue and an aqueous solution containing 0.1% by weight are dropped on a test piece with a dropper, and the test is performed at 25 ° C. under normal pressure using a black light FL20SBLB manufactured by Toshiba Lighting & Technology Corporation. Irradiation was performed for a predetermined time from a height of 5 cm immediately above the piece, and antibacterial properties were evaluated from the decolorizing effect. This evaluation method indicates that the greater the decolorizing effect, the higher the photocatalytic activity of titanium oxide and the higher the ability to oxidatively decompose organic substances, that is, the higher the antibacterial property. Further, after irradiation for 20 hours, the substrate was washed with water, and the cleaning property (antifouling property) was evaluated from the degree of the trace of the drop of the aqueous solution. Table 2 shows the evaluation results. Comparative Example 1 An inorganic plate was produced in the same manner as in Example 1 except that the above-mentioned zirconium phosphate particles were not used for the outermost layer. Tables 1 and 2 show the evaluation results. (Comparative Example 2) After the water slurry containing the titanium oxide particles used in Example 1 was applied to the inorganic plate of Comparative Example 1, 800 ° C
To produce an inorganic plate provided with antibacterial properties. Tables 1 and 2 show the evaluation results.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

According to the present invention, the average particle diameter is from 0.2 to
Titanium oxide containing inorganic compound particles in the range of 10 μm, wherein the inorganic compound particles have pores having a maximum diameter of 250 nm or less, and the pores have an average particle diameter in the range of 5 to 200 nm. Since the particles are supported, 9
Even if fired at a high temperature of 00 to 1,350 ° C., titanium oxide hardly grows beyond the maximum diameter of pores to provide an inorganic plate having high photocatalytic activity and excellent antibacterial and antifouling properties. be able to. Further, since the photocatalytic activity is high, NOx can be rapidly decomposed by the photocatalytic reaction,
Further, it is possible to prevent a bad smell caused by the propagation of fungi.

Further, since firing is performed at a high temperature as described above,
It is difficult for the inorganic compound particles carrying titanium oxide to fall off,
An inorganic plate having high hardness and excellent wear resistance can be provided.

Further, silver, copper,
Provided is an inorganic plate capable of maintaining antibacterial properties even in an environment where the photocatalytic activity of titanium oxide is reduced when at least one metal selected from the group consisting of zinc, tin and nickel or an ion thereof is supported. can do.

Further, when the inorganic plate has a layered structure of the inorganic layer containing the above-mentioned inorganic compound particles and the inorganic layer not containing the same, the amount of the inorganic compound particles to be used can be reduced and the cost of the inorganic material can be reduced. Boards can be provided.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // B01J 35/02 ZAB B28B 11/00 F term (reference) 4G052 GA10 GA17 GA23 GB07 GB83 GC06 GC08 4G055 AA08 AB05 AC01 BA14 4G069 AA03 AA08 AA11 BA01A BA04A BA04B BA05A BA05B BA36A BB02A BC31A BC32A BC35A BC68A CA01 CA07 CA10 CA11 EA14 EB15Y EB18X EB18Y EB19 EC09X EC09Y FA01 FB30 FB68 FB70 FB71 FC07 4H0118 ABC18

Claims (6)

[Claims] An inorganic compound particle having an average particle diameter in the range of 0.2 to 10 μm, said inorganic compound particle having pores having a maximum diameter of 250 nm or less, and said pores having an average diameter of not more than 250 nm. An inorganic plate on which titanium oxide particles having a particle diameter in a range of 5 to 200 nm are supported. 2. The inorganic plate according to claim 1, wherein said inorganic compound particles carry at least one metal selected from the group consisting of silver, copper, zinc, tin and nickel or ions thereof. 3. A layered structure of an inorganic layer containing inorganic compound particles having an average particle diameter in a range of 0.2 to 10 μm, and an inorganic layer not containing said inorganic compound particles. Having pores with a maximum diameter of 250 nm or less,
An inorganic plate, wherein the pores carry titanium oxide particles having an average particle diameter in a range of 5 to 200 nm. 4. The inorganic plate according to claim 3, wherein the outermost layer is an inorganic layer containing the inorganic compound particles. 5. It has pores having an average particle diameter in the range of 0.2 to 10 μm and a maximum diameter of 250 nm or less, and
After forming a slurry containing the inorganic compound particles carrying titanium oxide particles having an average particle diameter in the range of 5 to 200 nm in the pores to form a sheet-like molded body, 900 to
A method for producing an inorganic plate, comprising firing at a temperature of 1,350 ° C. 6. Pores having an average particle diameter in a range of 0.2 to 10 μm and a maximum diameter of 250 nm or less, and
A slurry containing inorganic compound particles in which titanium oxide particles having an average particle diameter in the range of 5 to 200 nm are supported in the pores, and a slurry containing no inorganic compound particles are formed into sheet-like molded articles. After laminating these two types of sheet-shaped molded articles and integrating them by pressing, 9
A method for producing an inorganic plate, characterized by firing within the range of 00 to 1,350 ° C.