JP2002348182A - Method for manufacturing porous material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a very light weight porous material having the porosity 60% or more and enough strength at a comparatively inexpensive cost without giving bad appearance in firing process. SOLUTION: The method for manufacturing porous material consists of a modifying process of a slurry containing a structure component, which does not melt in firing, and a melting component which melts in firing, a process for admixing a gelling agent and air foams into the slurry, a forming process, a drying process, and a firing process for firing materials at temperatures of 400 to 1300 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a porous material.

[0002]

2. Description of the Related Art Ceramic building materials have excellent chemical resistance and durability.
It is widely used because it can also exhibit high texture and various design properties at the same time. Furthermore, in recent years, lightweight foam tiles have been proposed in order to facilitate construction. As a manufacturing method, for example, for a porous ceramic building material, a foaming agent such as glass powder or silicon carbide is mixed into a raw material and molded, and when they are foamed at the time of firing, the base foams to obtain a porous body. Method (Japanese Patent Publication No. 7-88248)
Also, a method is known in which a lightweight hollow balloon such as pearlite is mixed with a raw material, which is molded and fired to obtain a porous ceramic building material.

On the other hand, in a precision positioning device such as an air slide, a porous ceramic is used as a means for supplying a stable air flow for moving a slider in a non-contact state. As a method for producing the porous ceramics, a molded body to which an organic substance having a large particle size is added in advance and a pore is formed by decomposing the organic substance at the time of firing, or a porous foam made of an organic substance is produced. In addition to the method of impregnating and solidifying a slurry containing the new ceramic powder therein, and then solidifying and then decomposing the organic foam by firing, a slurry is prepared by dispersing a new ceramic powder such as alumina or silicon nitride in a solvent,
A method has also been proposed in which a foam and a gelling agent are mixed with the mixture, the mixture is gelled, molded, dried, degreased, and fired to obtain a porous ceramic body (JP-A-6-2935).
72, JP-A-7-187852).

For example, JP-A-6-293572 discloses oxide-based new ceramics such as alumina, mullite and zirconia, or non-oxide-based new ceramics powder slurry such as silicon carbide, silicon nitride, aluminum nitride, boron nitride and graphite. , Bubble diameter is 10 to 200
A slurry prepared by adding and stirring a foaming liquid having a particle size of 0 μm and a derivatized protein is poured into a mold, and the derivatized protein contained in the slurry is gelled. A lightweight fired ceramic molded body which is fired at 1500 ° C. is disclosed.

Japanese Patent Application Laid-Open No. Hei 7-187852 discloses a slurry preparation step for preparing a ceramic slurry in which a new ceramic powder such as alumina and a curable organic substance are dispersed or dissolved in a solvent. A curing agent is added, and a slurry foaming step of foaming the ceramic slurry by stirring, a ceramic slurry in a bubble-retained state from the slurry foaming step is molded and cured, and a molding and curing step of drying, and a molded body from the molding and curing step are dried. A method for producing a porous ceramic body, comprising a drying and firing step of firing at about 1650 ° C. is disclosed.

[0006]

As described above, in the case of porous ceramic building materials, a method utilizing foaming at the time of firing and a method utilizing a hollow lightweight balloon are known. If the porosity is increased, deformation during firing due to foaming is large, and it is difficult to increase the porosity to 60% or more in the case of using a balloon, and the intended effects of weight reduction, soundproofing, heat insulation, etc. can be sufficiently obtained. Did not.

[0007] JP-A-6-293572 and JP-A-7-18
In the method described in No. 7852, since refined fine ceramics is used as a raw material, it is necessary to perform sintering at a very high temperature of 1400 ° C. or more in order to obtain strength with high porosity. For this reason, not only is the raw material cost high, but also the energy consumed is large, and the maintenance of the furnace material must be performed frequently, which is uneconomical. Furthermore, even when glazing is carried out to improve the design, if the firing is performed only once, the melting temperature of the glaze tends to be too low due to too high a temperature, resulting in poor appearance. For that reason, if you try to glaze,
It required two firings, which was also uneconomical.

The present invention has been made in view of the above circumstances, and compared a very lightweight porous material having sufficient strength and a porosity of 60% or more without exhibiting poor appearance during firing. It is an object of the present invention to provide a method which can be manufactured at low cost.

[0009]

In order to solve the above problems, in one embodiment of the present invention, a. Preparing a slurry containing a skeletal component that does not melt during firing and a melt component that melts during firing, b. Mixing a gelling agent and air bubbles into the slurry; c. Forming; d. Drying; e. Baking at a baking temperature of 400 to 1300 ° C., and a method for producing a porous material. The slurry contains a melting component that melts during firing, and contains a gelling agent and air bubbles, so that 4
By sintering at a low temperature of 00 to 1300 ° C., the porosity is 60% while having a sufficient bending strength of 1 MPa or more.
The above lightweight porous material can be provided.

In another aspect of the invention, there is provided a method comprising: a. Preparing a slurry containing a skeletal component that does not melt during firing and a melt component that melts during firing, b. Mixing a gelling agent and air bubbles into the slurry; c. Forming; d. Drying; f. After performing the step of glazing, e. A step of firing at a firing temperature of 400 to 1300 ° C.
The slurry contains a melting component that melts during firing, and contains a gelling agent and air bubbles, so that the
Firing at a low temperature of 1300 ° C, bending strength 1M
It is possible to provide a lightweight porous material having a porosity of 60% or more while having a sufficient strength of Pa or more. Also, 400-13
Since firing can be performed at a temperature as low as 00 ° C., firing can be performed only once when glazing is performed to improve design properties.

[0011] In a preferred aspect of the present invention, the molten component is 5 to 5 parts by weight based on the total amount of solids in the slurry.
In order to contain 70% by weight. By containing the molten component in an amount of 5% by weight or more, the fired body has sufficient strength even when fired at a low temperature of 400 to 1300 ° C. This is probably because the liquid phase sintering mechanism works even at such low temperatures. When the melting component is 70% or more, when the softening temperature of the solution component is reached at the time of firing, most of the components constituting the fired body are melted, the melt viscosity is excessively reduced, the shrinkage and deformation are increased, and the pores can be maintained. Since it is lost, the content is set to 70% by weight or less.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The production method of the present invention is described below.
This will be described in more detail. In the present invention, the "skeleton component that does not melt at the time of firing" reacts with other components at the time of firing,
Regarding the components that leave particles irrespective of not reacting, for example, kaolinite, halloysite, montmorillonite, sericite, pyrophyllite, aluminosilicate such as talc, quartz, wollastonite and the like are preferably used. it can.

In the present invention, the term "molten component that melts during firing" refers to a component that reacts with other components during firing or melts as a single component and does not remain as particles, such as feldspar or glass. Etc. can be suitably used.

In the present invention, the preparation of the “slurry containing a skeletal component that does not melt during firing and a melt component that melts during firing” is basically performed using the “skeletal component that does not melt during firing” defined above. And the “melting component that melts during firing” is suspended in water. put it here,
A raw material having both a “skeleton component that does not melt during firing” and a “melt component that melts during firing” may be suspended in water. As such raw materials, clay mineral raw materials generally used as ceramic raw materials and raw materials mined from raw materials of clay minerals are extracted after extracting the used parts such as clay and quartzite, and are usually used. Various types of glass waste such as Kira, glass bottles, fluorescent lights, discarded vehicle window glass and glass discharged from glass factories, tile waste and glaze sludge discharged from tile factories, thermal power plants Coal ash (fly ash) discharged after burning coal in the slag, molten slag discharged from steelworks,
What is discharged as industrial waste, such as incineration ash of sludge discharged after incineration of sludge discharged from sewage purification facilities, etc., can also be used effectively.

In the present invention, the term "gelling agent" refers to any one or more of the following materials that cause a gelling reaction. (1) Polymerization-curing reaction of monomer (2) Hydration-curing reaction (3) Specific salting-out reaction In the case of polymerization-curing reaction of a monomer, the “gelling agent” is the monomer, for example, methacrylamide, acrylamide, polyvinyl Alcohol, polyvinyl ether, ethylene glycol and the like can be suitably used. The “gelling agent” in the case of the hydration curing reaction is a substance that hydrates and cures. For example, agar, gelatin, alginate, carrageenan, pectin, gums and the like can be suitably used. Agar in this,
Gelatin, carrageenan, pectin, and gums need to be heated to an appropriate temperature for dissolution, and then exhibit a gelling property when cooled or left at room temperature. For example, agar is heated and melted at about 80 ° C. or more, and then gelled at about 40 ° C. or less. Similarly, gelatin is dissolved at about 30 ° C. or more, and carrageenan and pectin are heated and dissolved at about 40 ° C. or more.
Gelation occurs at a temperature of 0 ° C. or lower. Alginate is easily dissolved in water at normal temperature, and gelled by adjusting the pH and adding a small amount of a substance containing calcium ions such as calcium chloride or calcium sulfate. As the specific salting-out reaction, gelation by reaction between water glass and cement, reaction between water glass and an acid such as sodium carbonate hydroxide and the like can be used. The “gelling agent” herein is defined as both water glass and cement, and both water glass and an acid such as sodium carbonate hydroxide. From the viewpoint of cost, it is preferable to use agar, gelatin, alginate, and water glass as the “gelling agent”.

In the present invention, the method of “mixing bubbles” includes, for example, adding a surfactant generally known as a foaming agent to a slurry, and then mechanically stirring the slurry, vibration by ultrasonic waves or the like. , A gas is blown into a perforated plate (body), or a bubble is generated by a chemical reaction. Here, an anionic surfactant is preferably used as the surfactant, and an alkyl sulfate, an alkylbenzene sulfonate, a polyoxyethylene alkyl sulfate, a fatty acid salt and the like can be used. And amphoteric surfactants can be used as a mixture, and lauryldimethylcarboxymethylbetaine and the like can be used as the amphoteric surfactant, but are not limited to these examples.

The smaller the crushed particle size of the "skeleton component that does not melt during firing" and "the melt component that melts during firing" in the slurry, the larger the amount of bubbles in the slurry, but the crushing time, crushing cost, and reactivity during calcination. Considering the average particle size of 5
25 μm is preferred.

In the present invention, the "forming step" includes, for example, slip casting, pressure casting, in which a cell-containing slurry having fluidity is poured into a mold, and the fluidity of the cell-containing slurry is reduced, and its plasticity and shape retention are reduced. Injection molding, extrusion molding, and the like using a material having a high value can be performed, but the method is not limited to these methods. In addition, the shape is a small plate-shaped siding such as 50mm, 100mm square such as tile, 900mm × 1 such as siding or panel.
It is possible to make a large plate-like thing like 800 mm, and to make a rough surface by the shape of the mold, and to make porous ceramic building materials of various shapes such as balls of sanitary ware and washstands, The size and shape are not limited. In addition, the material of the mold used in molding can be any of a plaster mold, a mold, a resin mold, and the like, which are generally used as a casting mold, and is not limited by the material.

In the present invention, the “drying step” comprises 5
It is performed at about 0 ° C. to 150 ° C.

After performing the "forming step" and the "drying step", a glaze step may be performed. By covering the surface of the porous material of the present invention with glaze, paint, or the like, it is possible to provide a design, a surface that does not absorb water, and a surface that is not easily stained.

In the present invention, the “firing step” is 40
This is performed at a firing temperature of 0 to 1300 ° C. The temperature is appropriately selected depending on the components of the slurry component and the ratio thereof. In the porous material of the present invention, the component to be melted binds the skeletal component at the firing temperature to form a dense structure. Among the formulations containing components that melt during firing in the range of 10 to 70% by weight, for example, by selecting the formulation and firing temperature as shown in the following examples, the porosity is 60% or more and the bending strength is 1 MPa or more. A porous material having the following properties can be produced. The porous body thus produced has the same porosity and strength as the alumina or silicon nitride porous body produced at a firing temperature of 1400 ° C. or higher.

Since the porous material of the present invention is a method of maintaining the air bubbles mixed in the slurry to form pores of the porous material, controlling the air bubbles of the slurry reduces the pore diameter and porosity of the fired body. It is possible to control. The range is 10 to 1000 μm in average pore diameter, and the porosity is 40 to 95%.
Can be controlled by The control of the bubbles can be easily controlled by selecting the raw material, adjusting the pulverized particle size, viscosity and pH of the raw material slurry, adjusting the amount of the gelling agent and the amount of the introduced bubbles.

At the time of preparing the raw material, a coagulation of the raw material can be prevented by using a peptizer according to the state of the slurry. Examples of peptizers include polycarboxylates and sodium tripolyphosphate. Conversely, when the viscosity of the slurry is too low to cause precipitation of the raw material, it can be adjusted using a flocculant. Examples of the coagulant include potassium chloride, magnesium chloride, magnesium sulfate, barium sulfate and the like. However, peptizers and flocculants are not limited to these examples. If the viscosity of the slurry at this time is too high, it is difficult to form bubbles. If the viscosity is too low, the solid content precipitates. Therefore, the viscosity is preferably 100 to 500 mPa · s.

A TiO ₂ photocatalyst may be arranged on the surface of the porous material of the present invention. By doing so, antifouling property, antibacterial property, N
It can be a porous material that exhibits functions such as _OX decomposability.

The present invention is not limited to, but is not limited to, tiles used as wall and flooring, ceramic siding, ALC
It can be suitably used for building materials such as panels.

[0026]

EXAMPLE 1 55% by weight of waste glass, 35% by weight of clay, and 10% by weight of a waste mainly composed of alumina, 54% by weight of water were added and pulverized by a pot mill to obtain an average particle size of 10 μm and a viscosity of 300 mPa · s.
s slurry was prepared. Add agar to this slurry
After adding 5% by weight and stirring, 1% was added using an autoclave.
The mixture was heated and melted at a saturated vapor pressure of 05 ° C for 5 minutes. Anionic surfactant as a foaming agent, Emar AD
-25R (manufactured by Kao) was added in an amount of 0.3% by weight, and foaming was performed by mechanical stirring using a whisk until the volume became 3.0 times. During this stirring, the temperature of the slurry was controlled at about 70 ° C. so that the agar did not gel. The aerated slurry was cast into a mold before the agar had cooled to a temperature of about 40-50 ° C., at which point it began to gel. The molded product was left at room temperature for about 30 minutes, the temperature of the molded product was lowered, and the gelled product was released from the mold and dried with a dryer at 60 ° C for 3 hours. The dried body was fired at 1030 ° C. to obtain a porous material. This firing temperature of 1030 ° C. is a temperature at which the matrix portion containing no bubbles is densely sintered.
In the case where a foam not foamed in the above-described production process was molded and fired at this temperature, the water absorption of the fired body was less than 1%. Further, the shrinkage of the dense body and the porous material due to the firing was about the same of about 8%, and it was found that the air bubbles of the porous material were maintained. When the porosity of this porous material was measured by a mercury intrusion method, the porosity was 91%.
The bulk specific gravity was 0.61. Also, the cross section of this base material portion is S
Observation using EM revealed that the average pore diameter was about 10
It was 0 μm. Further, the flexural strength of this porous material was measured and found to be 4 MPa.

Example 2 Agar-dissolved slurry prepared in the same manner as in Example 1
The same foaming agent was added in an amount of 0.25% by weight, and foaming was performed so that the volume ratio became 2.5 times, and otherwise, a porous material was produced in the same manner. When the porosity and the pore diameter were measured in the same manner as in Example 1, the porosity was 88% and the bulk specific gravity was 0.7.
0, the average pore diameter was about 50 μm. Further, the flexural strength of this porous material was measured to be 6 MPa.

Example 3 Agar-agar slurry prepared in the same manner as in Example 1
The same foaming agent was added in an amount of 0.20% by weight, foaming was performed so that the volume ratio became 2.0 times, and the other method was the same as that described above to produce a porous material. When the porosity and the pore diameter were measured in the same manner as in Example 1, the porosity was 71% and the average pore diameter was about 130 μm. Further, the bending strength of this porous material was measured and found to be 10 MPa.

Example 4 45% by weight of roesite used as a ceramic raw material, clay 3
5% by weight, 15% by weight of tile waste, and 5% by weight of glaze sludge are added with 50% by weight of water and pulverized to obtain an average particle size of 8 μm.
m, a slurry having a viscosity of 350 mPa · s was prepared. In this slurry, the “molten component that melts during firing” is silicate glass supplied from glaze sludge. Anionic surfactant as a foaming agent, Emar AD
-25R (manufactured by Kao) and 1.5% by weight of amphoteric surfactant Amphitol 24B (manufactured by Kao) are added, and a perforated plate is inserted into the container, and air is blown into the container while stirring. Was 2.3 times. 5% by weight of JIS No. 3 water glass and 3% by weight of Portland cement were added to the bubble-containing slurry, and the mixture was further stirred and cast into a ball-shaped mold of a vanity while applying pressure. After about 1 hour, the mold was released, dried with a dryer at 100 ° C. for about 3 hours, and fired at 1150 ° C. to produce a porous material. The porosity of this porous material was 80%. Further, the flexural strength of this porous material was measured and found to be 2 MPa.

Example 5 Sludge incineration ash 40% by weight and tile waste 60% by weight
55% by weight of water was added and pulverized to prepare a slurry having an average particle size of 15 μm and a viscosity of 400 mPa · s. In this slurry, the “skeleton component that does not melt at the time of firing” is quartz or clay supplied from tile waste. The “melt component that melts during firing” is an anorthite supplied from sludge incineration ash. The sludge incineration ash is incinerated at a high temperature by adding a large amount of alkali such as lime when incinerating the sludge.Therefore, feldspar is purified as crystals in the treated ash, and this feldspar is melted here. Used as an ingredient. 8% by weight of methacrylamide as a monomer and 0.4% by weight of acrylamide as a cross-linking agent are added to the slurry, and the mixture is stirred.
0.7% by weight of Lipolan (manufactured by Lion) was added as a foaming agent in an oxygen atmosphere, and a volume ratio of 2.
Foaming was performed until the volume became three times, and 0.08% by weight of ammonium persulfate as an initiator and 0.05% by weight of tetramethylethylenediamine as a catalyst were added thereto, followed by further stirring to prepare a bubble-containing slurry. This slurry is 200 × 50 × 1
The mixture was cast into a 0 mm mold and turned into a gel. After 2 hours, the mold was released to prepare a gel-like porous molded body. This was dried in a dryer under controlled humidity, degreased at 800 ° C., and fired at 1100 ° C. to obtain a porous fired body. The porosity of this porous material is 7
It was 0%. Further, the flexural strength of this porous material was measured and found to be 8 MPa.

Example 6 A raw material for a porcelain mosaic tile base was wet-pulverized to prepare a slurry having an average particle size of 12 μm and a viscosity of 200 mPa · s. In this slurry, the “skeleton component that does not melt at the time of firing” is kaolinite supplied from clay or quartz supplied from silica stone. Also, in this slurry,
The “melt component that melts during firing” is feldspar supplied by Saba during the preparation of raw materials. 2. Gelatin was added to this slurry.
After adding 0% by weight and stirring, 7% was added using an autoclave.
The mixture was heated and dissolved under a saturated vapor pressure of 0 ° C. for 5 minutes. Anionic surfactant as a foaming agent, Emal AD-
0.8R by weight of 25R (manufactured by Kao) was added, and the mixture was foamed by ultrasonic vibration with stirring until the volume became 2.4 times. This bubble-containing slurry was cast into a 100 × 100 × 10 mm mold. Since gelatin gels at 5 to 10 ° C. by cooling, it is cooled to 5 ° C. in a refrigerator to gel.
After 1 hour, the mold was released. Since the gelatin deteriorated, this molded body was dried in a dryer at 40 ° C. to obtain a porous dried body. This was glazed with a glaze usually used for the tile by spraying and fired at 1250 ° C. to produce a porous tile. The porosity of this porous tile was 75%.

[0032]

According to the present invention, a very lightweight porous material having sufficient strength and a porosity of 60% or more can be produced relatively inexpensively without exhibiting poor appearance during firing. Can be provided.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideki Kobayashi 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-city, Fukuoka Prefecture Inside Totoki Equipment Co., Ltd. (72) Inventor Eri Omori 1865 Kasaharacho, Toki-gun, Gifu Yamase Co., Ltd. (72) Inventor Minoru Takahashi 3-60 Kibogaoka, Tajimi-shi, Gifu F-term (reference) 4G019 GA01 GA02 GA04

Claims (3)

[Claims] 1. A method according to claim 1, Preparing a slurry containing a skeletal component that does not melt during firing and a melt component that melts during firing, b. Mixing a gelling agent and air bubbles into the slurry; c. Forming; d. Drying; e. A step of firing at a firing temperature of 400 to 1300 ° C. 2. a. Preparing a slurry containing a skeletal component that does not melt during firing and a melt component that melts during firing, b. Mixing a gelling agent and air bubbles into the slurry; c. Forming; d. Drying; f. After performing the step of glazing, e. A step of firing at a firing temperature of 400 to 1300 ° C. 3. The method for producing a porous material according to claim 1, wherein the molten component is contained in an amount of 5 to 70% by weight based on the total amount of solids in the slurry.