KR20100050079A - Ceramic material having humidity controlling performance and preparing method thereof - Google Patents

Abstract

PURPOSE: A method for manufacturing humidity control ceramic mold body is provided to reduce manufacture cost by using gamma-alumina phase transformation of aluminium source. CONSTITUTION: A humidity control ceramic mold body contains a gamma-alumina. The gamma alumina is obtained by phase transformation of aluminum source selected from a group consisting of aluminum nitride, aluminum carbonate, chloroaluminum, dehydrate, aluminum hydroxide, aluminum chloride, aluminum nitrate, and alumina sol. The ceramic mold body further contains grain growth inhibito.

Description

Ceramic material having humidity controlling performance and preparing method

The present invention relates to a hygroscopic ceramic molded body and a method for producing the same.

Recently, as a new environmental problem, molds due to humid indoors as well as sick house syndrome and atopy due to hexavalent chromium generated from concrete walls or VOC gas generated from adhesives used to bond interior and exterior materials, etc. Problems such as this occur frequently.

In order to solve this problem, efforts are being made to develop functional products that absorb and remove harmful gases, absorb moisture when the humidity is high, lower the indoor humidity, and release absorbed moisture when drying. There is a situation.

Recently, Japan's INAX Corporation (INAX) launched a functional tile called eco-karat, which controls indoor humidity by adsorbing formaldehyde gas, living odor or VOC gas using ultra-fine porous ceramic tiles and exhibiting moisture absorption and moisture resistance. It was.

The eco carat uses a volcanic ash powder of a specific region such as allophen as a tile material. In this case, the humidity is good but the manufacturing cost is high due to expensive volcanic ash powder. In the case of using a rather low volcanic ash powder, there is a problem in that it is difficult to exhibit good quality and low humidity.

In addition, until now, products that are released in Korea as functional tiles generally have a moisture absorption function, but have a disadvantage in that the moisture-proof function is disadvantageous. there was.

The present invention has been made in order to solve the above problems, and an object thereof is to provide a humidified ceramic molded body containing γ-alumina having excellent humidity control function and deodorization function.

In addition, another object of the present invention is to provide a method for producing a humidity-absorbing ceramic molded body which can reduce manufacturing costs by phase-shifting a low-cost industrial aluminum source.

The present invention provides a humidified ceramic molded body containing γ-alumina as a means for solving the above problems.

In addition, the present invention as another means for solving the above problems, the first step of preparing a mixture comprising an aluminum source and a grain growth inhibitor that can be phase-transfer to γ-alumina; A second step of preparing a molded body using the mixture prepared in the first step; And a third step of heat-treating the molded product produced in the second step.

In addition, the present invention as another means for solving the above problems, (1) preparing a slurry or suspension using a mixture comprising an aluminum source and grain growth inhibitor that can be phase-transfer to γ-alumina; (2) impregnating or coating the ceramic compact with the slurry or suspension prepared in step (1); And (3) heat treating the ceramic molded body at a temperature of 800 to 1000 ° C.

According to the humidity-controlling ceramic molded body and the manufacturing method thereof according to the present invention, since the industrial aluminum source, which is a low-cost raw material, can be phase-transformed into γ-alumina by heat treatment, it is possible to provide a humidity-controlled ceramic molded body having excellent humidity control function and deodorization function. At the same time, it is possible to reduce the manufacturing cost of such a humidified ceramic molded body.

TECHNICAL FIELD The present invention relates to a humidified ceramic molded body comprising γ-alumina.

Hereinafter, the humidity-forming ceramic molded body of the present invention will be described in more detail.

As mentioned above, the moisture-proof ceramic compact of this invention contains (gamma) -alumina.

Here, γ-alumina is a transitional alumina, which can be transformed into other structures by constant heat treatment, has a large specific surface area and fine pore holes, and can exhibit excellent properties as a membrane, catalyst, catalyst carrier, and adsorbent. It is a substance.

The γ-alumina is formed on the surface of the micropores not only excellent humidity control function but also excellent deodorizing function. Therefore, γ-alumina absorbs moisture through the fine pores formed on the surface when the humidity is high, and lowers the humidity in the room. On the contrary, when the humidity is low, the γ-alumina functions to increase the indoor humidity.

The γ-alumina may be a commercial γ-alumina, but since such commercial γ-alumina is very expensive, it is preferable that the γ-alumina used in the present invention is a phase-change of a low-cost industrial aluminum source.

Here, the aluminum source may be any one selected from the group consisting of aluminum nitride, aluminum carbonate, aluminum chloride, aluminum chloride dihydrate, aluminum hydroxide, aluminum chloride, aluminum nitrate and alumina sol. However, the aluminum source is exemplified It is not limited, but by heat treatment All aluminum sources that can be phase-transformed into γ-alumina can be included therein.

On the other hand, the humidity-forming ceramic molded body of the present invention may further include a grain growth inhibitor.

The grain growth inhibitor serves to maintain a porous specific surface area by inhibiting grain growth that may occur during firing at a high temperature. In other words, the grain growth inhibitor inhibits grain growth of γ-alumina that may occur when the aluminum source is subjected to high temperature heat treatment to phase-transfer to γ-alumina, thereby reducing the amount of micropores due to the decrease in specific surface area of γ-alumina. The reduction can be prevented to maintain excellent humidity control and deodorization during firing due to high temperature heat treatment.

In addition, the grain growth inhibitor may be at least one selected from the group consisting of rare earth oxides, alkali metal oxides, alkaline earth metal oxides.

On the other hand, it is preferable that the moisture-proof ceramic compact of this invention contains 10-40 weight part of (gamma) -aluminas, and 1-5 weight part of particle growth inhibitors.

When the γ-alumina is less than 10 parts by weight, the humidity control function may be lowered. When the γ-alumina is more than 40 parts by weight, the sintering of the molded body may be lowered, thereby lowering the strength of the molded body.

In addition, when the grain growth inhibitor is less than 1 part by weight, there is a problem that the average particle diameter of γ-alumina may be increased by not exhibiting the grain growth inhibitory effect. When the grain growth inhibitor exceeds 5 parts by weight, the manufacturing cost is accompanied by a decrease in the humidity control function. This may increase.

In addition, the γ-alumina preferably has an average particle diameter of 1 to 100 µm, more preferably 1 to 50 µm.

If the average particle diameter of the γ-alumina is less than 1 µm, there is a problem that the strength of the molded body can be lowered and the manufacturing cost can be increased. If the average particle diameter is larger than 100 µm, the humidity control function may be lowered.

Moreover, it is preferable that (gamma) -alumina has a specific surface area of 150-350 m <^2> / g.

When the specific surface area of the γ-alumina is less than 150 m ² / g, there is a fear that the humidity control function is lowered, and when the γ-alumina exceeds 350 m ² / g, it may cause difficulty in the manufacturing process, raising the manufacturing cost There is.

The humidified ceramic molded body according to the present invention may be any one selected from a functional tile, a functional filter cartridge or a functional board.

However, the humidity-controlled ceramic molded body according to the present invention is not limited thereto, and may include all functional ceramic molded bodies requiring a humidity control function and a deodorization function.

For example, the hygroscopic ceramic molded body of the present invention includes a parent material; Binding material; It may be a functional tile further comprising one or more additives selected from the group consisting of diatomaceous earth, feldspar, pottery, lime and milky.

The parent material is not limited to a particularly limited material, and any material that can be used as a parent material in manufacturing a ceramic tile may include all materials, for example, clay may be used. The clay is preferably included in 40 to 70 parts by weight with respect to 100 parts by weight of the entire ceramic formed body.

The binding material is not limited to a particularly limited material, and may include any that can be used as a binding material in the manufacture of ceramic tiles. For example, frit powder or crushed glass powder may be used. The binding material is preferably included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the entire ceramic formed body.

When the binding material is included in less than 5 parts by weight, the strength of the molded body may be lowered, and when included in excess of 30 parts by weight, there is a problem that the humidity control function may be lowered.

In addition, the additive may be one or more selected from the group consisting of feldspar, pottery, lime, diatomaceous earth and milky agent, but is not limited thereto and may further include other additives that may improve the performance of the tile.

The additive is preferably contained in 5 to 30 parts by weight based on 100 parts by weight of the entire ceramic formed body.

Diatomaceous earth among the additives is porous having rich absorbency, and when added to a functional tile, it is possible to further improve the absorbing function.

In addition, the whitening agent is a powder added to give a white color to the glass product, may be one or more selected from the group consisting of chloride, tin, titanium, sulfate, phosphate, arsenate and fluoride, but is limited to the above-exemplified materials It is not.

Here, the humidity control ceramic molded body may further include an oil coating layer on the surface.

The oil sight layer may be composed of a first oil sight layer having a thin film form having a thickness of less than 50 μm, and a second oil sight layer formed on the first oil sight layer and having a glassy island having an average particle size of 100 to 500 μm dispersed thereon. have.

As a specific example of the method for forming an oil-based layer, first, a slurry liquid containing a low-density frit and a pigment having an average particle size of about 5 μm and a pigment are thinly applied to a thickness of about 50 μm to form a first oil-based layer. Subsequently, by spraying a high-density frit having an average particle size of about 50 μm in water and applying a spray, it is possible to form a second oil layer in which glassy islands having an average particle size of about 100 μm are dispersed on the surface of the molded body. Accordingly, the vitreous islands are only softened slightly without melting or wetting even after heat treatment, and thus exist in the form of protrusions.

Therefore, in the case of forming the oil-seeding layer as described above, micropores are naturally formed in the first oil-seeding layer having a thickness of 50 μm, and glaze protrusions in the form of islands are formed in the second oil-seeking layer. The surface of the oil is applied, but the inside is made of a form in which a large amount of micropores through which moisture or gas passes.

Here, it is preferable that the thickness of a 1st sheet oil layer is 10-50 micrometers. If the thickness of the first oil layer is less than 10㎛ may have a problem that the powder is not buried because of the effect of oil, when the 50㎛ or more may significantly reduce the micropores in the oil layer to reduce the humidity function Can be.

In addition, the present invention comprises a first step of preparing a mixture comprising an aluminum source and particle growth inhibitor that can be phase-transformed into γ-alumina; A second step of preparing a molded body using the mixture prepared in the first step; And a third step of heat-treating the molded product produced in the second step.

In the first step, the mixture may be prepared by a wet ball mill or spray drying process, and the resulting mixture may be a spherical granular powder having a uniform water content of 6 to 8% and an average particle size of 200 to 300 μm. have.

In the case of preparing the mixture as described above, the microstructure may be improved at the time of dry forming, the yield may be improved, and the productivity may be improved.

On the other hand, the molded article in the second step can be produced through a dry molding method.

In addition, the second step preferably further includes a drying step of drying the produced molded body at a temperature of 200 to 250 ℃. By adding such a process, it is possible to suppress defects such as deformation of the molded body or explosion in the short time passing through the hot gas continuous furnace.

Moreover, it is preferable to further include the process of carrying out the oil-base treatment of the dried molded object after a drying process.

On the other hand, the heat treatment of the third step is preferably carried out for 5 to 20 minutes at a temperature of 800 to 1000 ℃ in a continuous furnace.

Since the heat treatment is performed in a continuous furnace, it is possible to improve productivity, and also, there is an advantage that energy can be saved because the heat treatment is performed at a relatively low temperature of 800 to 1000 ° C.

When heat-treating the molded body at less than 800 ℃, there is a problem that the plastic strength of the molded body can be lowered, when the heat treatment at a temperature exceeding 1000 ℃, the γ-alumina of the transition state by the phase change to α-alumina, the humidity control function There is a problem that this can be significantly reduced.

In addition, the present invention comprises the steps of (1) preparing a slurry or suspension using a mixture comprising an aluminum source and a grain growth inhibitor that can be phase-transformed into γ-alumina; (2) impregnating or coating the ceramic compact with the slurry or suspension prepared in step (1); And (3) heat-treating the ceramic formed body at a temperature of 800 to 1000 ° C.

For example, a mixture comprising an aluminum source that can be phase-transformed into γ-alumina and a grain growth inhibitor is prepared in the form of a slurry, and the slurry is impregnated and dried in a circular honeycomb made of ceramic paper and then dried in a range of 800 to 800. By heat-processing at the temperature of 1000 degreeC, the ceramic molded object which phase-transformed the aluminum source into (gamma) -alumina can be manufactured.

The ceramic molded body thus prepared can be applied to a rotor having a dehumidifying function because a large amount of γ-alumina particles having a high humidity control function are supported in the microstructure of the ceramic fiber honeycomb with a large porosity.

Hereinafter, a humidity control ceramic molded body according to an embodiment of the present invention will be described. However, such an embodiment is only one aspect of the present invention, and the scope of the present invention is not limited by the following examples.

Example 1

Water content by uniformly mixing 50 parts by weight of clay, 5 parts by weight of diatomaceous earth, 5 parts by weight of a mixture of pottery stone and feldspar, 20 parts by weight of aluminum hydroxide, 5 parts by weight of barium oxide, and 15 parts by weight of frit through a spray drying process. Spherical granular powder having an average particle size of 8% and 300 µm was prepared, and the granular powder was dry-molded at a pressure of about 300 tons to prepare ceramic tiles having a width, length, and thickness of 316 mm, 316 mm, and 8 mm, respectively.

Next, the ceramic tile was dried in a continuous drying furnace at 250 ° C., and then a slurry liquid containing a low-density frit and a pigment having an average particle size of 5 μm was applied to the ceramic tile in a thin thickness of 50 μm, followed by an average particle size of 50 μm. By spray-coating a high-density frit having a thickness of µm, water was formed on the surface of the ceramic tile with a glassy island having an average particle size of about 100 µm in the form of a projection.

Finally, the ceramic tile was immediately put into a gas continuous furnace (RHK) and heat treated at a temperature of 800 ° C. for 10 minutes to prepare a functional tile.

[Example 2]

A functional tile was prepared in the same composition as in Example 1 except that the heat treatment temperature was 900 ° C.

Example 3

A functional tile was prepared in the same composition as in Example 1 except that the heat treatment temperature was set at 1000 ° C.

Example 4

A functional tile was prepared in the same manner as in Example 2, except that the clay content was 60 parts by weight and the aluminum hydroxide content was changed to 10 parts by weight.

Example 5

A functional tile was prepared in the same manner as in Example 2, except that the clay content was 40 parts by weight and the aluminum hydroxide content was changed to 30 parts by weight.

Example 6

A functional tile was prepared in the same manner as in Example 2 except that the clay content was 55 parts by weight and the frit content was changed to 10 parts by weight.

Example 7

A functional tile was prepared in the same manner as in Example 2, except that the content of clay was 45 parts by weight and the content of frit was changed to 20 parts by weight.

[Comparative Example]

The same process as in Example 1 was carried out except that a mixed powder containing 65 parts by weight of clay, 20 parts by weight of frit, 5 parts by weight of barium oxide, 5 parts by weight of diatomaceous earth, and 5 parts by weight of a mixture of feldspar and pottery was used. After the mixed powder was prepared, a tile molded body was prepared.

[Experimental Example]

1. Formaldehyde gas adsorption test

The functional tiles prepared through Examples 1 to 7 and Comparative Examples were cut into 10 cm * 10 cm to measure the initial rate of formaldehyde adsorption for 5 minutes.

2. Moisture absorption test

Water-repellent coating on the side and back of the sample cut into 10cm * 10cm functional tiles prepared through Examples 1 to 7 and Comparative Examples to allow moisture to be absorbed and dehydrated only to the front, respectively, room temperature 25 ℃, room humidity (Room Humidity; RH) After maintaining for 12 hours in a 50% constant temperature and humidity cabinet, it was put again in a constant temperature and humidity chamber of 25 ℃, room humidity 90% for 12 hours.

After reciprocating the process in three cycles, the weight of each process was measured, and the weight difference in moisture absorption and the weight difference in moisture proof were converted into moisture absorption and moisture absorption (g) per area (m ² ). Was calculated, and the results are shown in Table 1 below.

Claims (16)

Humidity ceramic molded body containing (gamma) -alumina. The method of claim 1, γ-alumina is a humidity control characterized in that the phase change of any one aluminum source selected from the group consisting of aluminum nitride, aluminum carbonate, aluminum chloride, aluminum chloride dihydrate, aluminum hydroxide, aluminum chloride, aluminum nitrate and alumina sol Ceramic molded body. The method of claim 1, Humidity ceramic molded body further comprises a grain growth inhibitor. The method of claim 3, wherein The grain growth inhibitor is a hygroscopic ceramic molded body, characterized in that at least one selected from the group consisting of rare earth oxides, alkali metal oxides and alkaline earth metal oxides. The method of claim 3, wherein 10 to 40 parts by weight of γ-alumina and 1 to 5 parts by weight of the grain growth inhibitor. The method according to any one of claims 1 to 5, Humidity ceramic molded body, characterized in that any one selected from a functional tile, a functional filter cartridge or a functional board. The method according to any one of claims 1 to 5, The parent material; Binding material; Humidity ceramic molded body, characterized in that the functional tile further comprises one or more additives selected from the group consisting of diatomaceous earth, feldspar, stone, lime and milk. The method of claim 7, wherein Humidity ceramic molded body further comprises a fuel oil layer on the surface. The method of claim 8, The oil sight layer is composed of a first oil sight layer having a thin film form having a thickness of less than 50 μm, and a second oil sight layer formed on the first oil sight layer and having a glassy island having an average particle size of 100 to 500 μm dispersed thereon. Humidity ceramic molded body made of. a first step of preparing a mixture comprising an aluminum source that can be phase-transformed into γ-alumina and a grain growth inhibitor; A second step of preparing a molded body using the mixture prepared in the first step; And A method for producing a humidity-sensitive ceramic molded body comprising a third step of heat-treating the molded body produced in the second step. The method of claim 10, In a first step the mixture is prepared by a wet ball mill or spray drying process. The method of claim 10, In the second step, the molded body is produced by a dry molding method. The method of claim 10, After the second step, the method further comprises a drying step of drying the prepared molded body at a temperature of 200 to 250 ° C. The method of claim 13, After the drying step, further comprising a step of subjecting the dried molded body to a milking process. The method of claim 10, In the third step, the heat treatment is performed at a temperature of 800 to 1000 ° C. in the continuous furnace. Characterized in that it is carried out for 5 to 20 minutes. (1) preparing a slurry or suspension using a mixture comprising an aluminum source and a grain growth inhibitor that can be phase-transformed into γ-alumina; (2) impregnating or coating the ceramic compact with the slurry or suspension prepared in step (1); And (3) A method of producing a humidity-sensitive ceramic molded body comprising the step of heat-treating the ceramic molded body at a temperature of 800 to 1000 ℃.