JP2002273129A - Ceramic film filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic film filter hard to generate the peeling of a base material and a seal part and the peeling of a filter film and the seal part by washing, using an alkali or acid aqueous solution, and capable of being manufactured at a low baking temperature. SOLUTION: The ceramic film filter is equipped with the base material 1 formed by baking a raw material containing aggregate, the filter film 2 obtained by baking the raw material containing ceramic particles and a sintering aid II applied to the base material 1 and the seal part 3 obtained by baking the raw material containing a sealant applied to a part of the base material 1 and a part of the filter film 2. When the content (mass %) of an alkali component in the sintering aid is set to y and the content of the alkali component in the sealant is set to z, a formula : -3.0<=y-z<=+3.0 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a ceramic membrane filter used for filtering fluids such as liquids and gases,
In particular, the present invention relates to a ceramic membrane filter that does not cause peeling of a seal portion during cleaning of the ceramic membrane filter.

[0002]

2. Description of the Related Art A ceramic membrane filter is a filter using a ceramic porous body and has excellent physical strength, durability, corrosion resistance, etc., and is therefore used in a wide range of fields such as water treatment, exhaust gas treatment, and medicine / food. Used for removing suspended substances, bacteria, dust and the like in liquids and gases.

[0003] In a ceramic membrane filter, a porous ceramic body may be used as a filter medium as it is. However, in order to improve both filtration performance and fluid permeability, a filtration membrane made of ceramic on the surface of a porous ceramic body as a base material. It is common to form For example, the average pore diameter of the filtration membrane is configured to be as small as about 0.01 to 1.0 μm to ensure the filtration performance, while the average pore diameter of the base material is configured to be as large as about 1 to several hundred μm, and the inside of the base is Has been practiced to reduce the flow resistance of the fluid and improve the amount of fluid permeation.

As the ceramic membrane filter, those obtained by processing a base material into various shapes according to the purpose of filtration are used, and the base material is formed in a tubular shape having a single flow passage or a plurality of parallel flow passages. Honeycomb-shaped or monolith-shaped ones having the following are widely used. A filter in which a filtration membrane is formed on the surface of a tube-shaped, honeycomb-shaped or monolith-shaped substrate, for example, an inner peripheral surface of a substrate having a flow passage therein, is housed in a housing. It is used as a cross-flow type filter by having a structure in which the opening end face side is air-tightly isolated by an O-ring or the like.

According to the cross-flow type filter, a fluid to be treated, such as a gas or a liquid, is supplied into the flow passage from one end face of the substrate, so that the filtered fluid that has passed through the filtration membrane on the inner surface of the flow passage is formed. The fluid to be treated, which is collected from the outer peripheral surface side of the material and not filtered, can be collected from the other end surface side of the base material.

However, as shown in FIG.
Simply isolating the end of the substrate 1 with the O-ring 11 causes the fluid to be treated to enter the inside of the substrate 1 from the end surface of the substrate 1 where the filtration membrane 2 is not formed. And contaminate the already filtered filtration fluid.

Therefore, as shown in FIG. 1, there has been proposed a membrane separation device in which at least one end of the base material 1 and the filtration membrane 2 near the end of the base material 1 are covered with the sealing portion 3 (Japanese Patent Application Laid-Open No. Sho 61). -8106). Such a structure is applied to the substrate 1
It is possible to prevent the fluid to be treated from intruding from the end face, and since the non-treated fluid always passes through the filtration membrane 2, the intended filtration can be performed, and the contamination of the filtered fluid that has already been filtered can also be prevented. Useful in that respect.

In general, a ceramic membrane filter having such a structure is prepared by adding a molding aid and the like to an aggregate and a sintering aid, kneading and molding the mixture, and then performing a first firing to obtain a base material. 1 is formed, then a raw material containing ceramic particles and a sintering aid is applied to the surface of the base material, and a second sintering is performed to form a filtration membrane 2, and finally a sealing agent such as glaze is applied. The raw material containing is applied to the end of the base material and the surface of the filtration membrane near the end of the base material, and is subjected to the third baking, whereby the seal portion 3 is formed.

Further, as exemplified in FIG. 2, a ceramic membrane filter including an intermediate layer 5 between the filtration membrane 2 and the substrate 1 is also used. In the case where the intermediate layer 5 is provided between the filtration membrane 2 and the substrate 1, in general, after the substrate is formed by the first baking, ceramic particles for forming the intermediate layer 5 and a sintering aid are included. The raw material is applied to the substrate 1 and subjected to a second baking to form the intermediate layer 5, and then a raw material containing ceramic particles for forming the filtration membrane 3 is applied to the surface of the intermediate layer 3 to form a third layer. Is fired to form a filtration membrane 2, and finally, a raw material containing a sealing agent is applied to the end of the base material 1 and the surface of the filtration membrane 2 near the end of the base material 1, and the fourth baking is performed. It is manufactured through a process in which the seal portion 3 is formed.

In the case of manufacturing any of the ceramic membrane filters shown in FIGS. 1 and 2, the base material undergoes a plurality of firing steps, and the second firing step is performed to prevent deformation and buckling of the base material. In general, the subsequent firing temperature is set lower than the first firing temperature. Therefore, generally, the composition of the sintering aid used for forming the base material, the sintering aid used for forming the filtration membrane, and the composition of the sealant used for forming the seal portion are sequentially changed so that the melting temperature becomes lower. Thus, it is manufactured by sequentially lowering the heating temperature as it goes through the process. Generally, a mixture of potassium feldspar and kaolin is used as a raw material of a sintering aid for forming a base material, and kaolin or the like is used as a raw material of a sintering aid for forming a filtration membrane.
So-called self-sintering without using a sintering aid is also performed. For forming the seal portion, glaze or the like used for ceramics is used as a sealant.

When such a ceramic membrane filter is used for a long period of time for filtering a fluid, as the amount of filtration increases, suspended substances, particularly organic suspended substances, contained in the undiluted filtrate concentrate in pores of the filter and pass through. Properties are significantly impaired. In order to remove this substance, it is common practice to dissolve and remove the suspended substance clogged in the pores using an aqueous solution of an alkaline substance such as caustic soda, citric acid or sodium hypochlorite.

However, when washing is repeatedly performed using an aqueous solution of an alkaline substance, citric acid, sodium hypochlorite, or the like, a phenomenon in which the base material and the sealing portion and the filtration membrane and the sealing portion are separated sometimes occurs.

[0013]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances.
An object of the present invention is to provide a ceramic membrane filter in which a base material and a sealing portion, and a filtration film and a sealing portion are not easily separated from each other in washing using an aqueous solution of an alkaline substance, citric acid, sodium hypochlorite, or the like. Another object of the present invention is to provide a ceramic membrane filter that can be manufactured at a lower firing temperature while achieving the above object.

[0014]

Means for Solving the Problems According to the present invention, as a result of examining the above-mentioned peeling phenomenon in detail, a specific component, particularly an alkali component, is concentrated on the interface between the base material and the sealing portion and between the filtration membrane and the sealing portion. The interface becomes a weak point for a cleaning agent such as an acid or an alkali, and the separation phenomenon has occurred because the separation has occurred at the interface between the base material and the seal portion and between the filtration membrane and the seal portion, and the concentration of the alkali component at the interface is suppressed. It has been found that the concentration of the alkali component at the interface can be suppressed by reducing the difference in the concentration of the alkali component contained in the sintering aid or the sealant for forming the two layers constituting the interface. It is based on finding that it can be done.

That is, according to the present invention, a base material obtained by firing a raw material containing at least an aggregate and a raw material containing at least ceramic particles and a sintering aid (II) are applied to the base material and fired. A ceramic membrane filter comprising: a filtration membrane comprising: a raw material containing at least a sealing agent; and a seal portion formed by applying and firing a part of the base material and a part of the filtration membrane. When the value of the alkali component content (% by mass) in the sintering aid (II) is y and the value of the alkali component content (% by mass) in the sealant is z, -3.0 ≦ y There is provided a ceramic membrane filter (first invention), wherein a relationship of −z ≦ + 3.0 is satisfied. Thereby, separation of the filtration membrane and the seal portion is suppressed.

Further, according to the present invention, a base material obtained by firing a raw material containing at least an aggregate and a sintering aid (I), and a raw material containing at least ceramic particles are applied on the base material and fired. A ceramic membrane filter comprising: a filtration membrane comprising: a raw material containing at least a sealing agent; and a seal portion formed by applying and firing a part of the base material and a part of the filtration membrane. When the value of the alkali component content (% by mass) in the sintering aid (I) is x and the value of the alkali component content (% by mass) in the sealant is z,
A ceramic membrane filter (second invention) is provided, wherein a relationship of −3.0 ≦ x−z ≦ + 3.0 is provided. Thereby, peeling of the base material and the seal portion is suppressed.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An important feature of the first invention is that the value of the alkali component content (mass%) of the sintering aid (II) used for forming a filtration membrane is y, When the value of the alkali component content (% by mass) of the sealing agent used is z, −3.0 ≦ yz ≦ + 3.0, preferably −2.8 ≦ yz ≦ + 2.8, More preferably, the relationship of -2.5 ≦ yz ≦ + 2.5 is satisfied. When the difference between the alkali component content in the sintering aid (II) and the alkali component content in the sealant is within the above-described range, the alkali component is reduced when the sealant is fired to form a seal portion. The phenomenon of concentration at the interface between the seal portion and the filtration membrane is suppressed, and the problem of peeling during washing is less likely to occur.

In the first invention, the alkali component content (% by mass) refers to the composition of an object to be measured (sintering aid or sealant) by a known method such as wet chemical analysis or fluorescent X-ray quantitative analysis. N obtained as an oxide by measurement
It is a percentage of the total mass of a ₂ O and K ₂ O with respect to the total mass of the measurement object.

In the first invention, the sintering aid (II)
Although not particularly limited, one or more ceramic materials such as clays such as kaolin, ceramic glazes, borosilicate glazes, and glazes such as zirconia-containing borosilicate glazes are preferable, and more preferably these ceramic materials are used. Including material frit. In the present invention, the frit refers to a material that is cooled and pulverized after a ceramic material or the like is melted and homogenized, and the frit reduces the melting temperature of the material. The firing can be performed at a low temperature, the deformation of the base material due to excessive firing can be prevented, the energy required for firing can be reduced, and the ceramic membrane filter can be manufactured at lower cost.

In the first invention, the sealant used to form the seal portion 3 is preferably a glaze such as a ceramic glaze, a borosilicate glaze, or a zirconia-containing borosilicate glaze, and more preferably these frit. is there. By using the frit, the effects of preventing deformation of the base material and reducing costs can be obtained in the same manner as described above.

[0021] Materials such as ceramic materials and glazes suitably used for the sintering aid (II) and the sealant generally contain alkali components such as sodium and potassium. Therefore, when the value of the alkali component content (% by mass) of the sintering aid (II) is y and the value of the alkali component content (% by mass) of the sealant is z, −3.0 ≦ y− z
≤ + 3.0, preferably -2.8≤yz≤ + 2.8,
More preferably, by selecting a combination of the sintering aid (II) and the sealant so as to satisfy −2.5 ≦ yz ≦ + 2.5, the movement of the alkali component during firing is suppressed, and the alkali component at the interface is suppressed. Concentration is suppressed. The most preferable combination is to use frit having the same composition as both materials. By having the same composition, the difference between the alkali component contents of the two becomes zero, the concentration of the alkali component at the interface is sufficiently suppressed, and firing at a low temperature becomes possible by using a frit.

An important feature of the second invention is that the value of the alkali component content (mass%) of the sintering aid (I) used for forming the base material 1 is x, and that the seal portion 3 is formed. When the value of the alkali component content (% by mass) of the sealing agent used is z, −3.0 ≦ x−z ≦ + 3.0, preferably −2.8 ≦ x−z ≦ + 2.8, More preferably-
2.5 ≦ x−z ≦ + 2.5. When the difference between the alkali component content in the sintering aid contained in the base material 1 and the alkali component content in the seal portion is within the above range, the alkali component is mixed at the interface between the seal portion and the base material during firing of the sealant. Is suppressed, and the problem of peeling during cleaning is suppressed.

In the second invention, the same sealant as described in the description of the first invention is preferably used as the sealant. In the second invention, the sintering aid (I) used for forming the substrate 1 preferably has an average particle diameter of 5 μm.
These are the following ceramic particles: More preferably, one or a mixture of two or more particles of feldspar such as potassium feldspar, clay such as kaolin, alumina, silica, zirconia, titania, cordierite and the like are used.

These materials also generally contain an alkali component such as sodium or potassium as described above. Therefore, similarly to the above, when the value of the alkali component content (% by mass) of the sintering aid (I) is x and the value of the alkali component content (% by mass) of the sealant is z, -3. 0
≦ x−z ≦ + 3.0, preferably −2.8 ≦ x−z ≦ +
2.8, more preferably -2.5 ≦ xz ≦ + 2.5
By selecting a combination of the sintering aid (I) and the sealant such that the following is satisfied, the movement of the alkali component during firing is suppressed, and the concentration of the alkali component at the interface is suppressed.

In the second invention, the sintering aid (I) used for forming the base material 1 may be a frit or a material that is not fritted, but the sealant is preferably a frit. More preferably, the sintering aid used to form the substrate 1 is a non-fritted material, and the sealant is a frit. More preferably, both are the same composition, the former is not fritted, and the latter is frit. Since the two have the same composition, the difference between the alkali component contents of the two becomes zero, and the concentration of the alkali component at the interface is sufficiently suppressed. Further, the former is not fritted, so that the base material is sufficiently sintered, and the latter is frit, so that firing at a low temperature is possible at the time of forming the seal portion, and the base material is excessively fired. Deformation is prevented, and the energy required for firing can be reduced, so that a ceramic membrane filter can be manufactured at lower cost.

In the present invention, a combination of the sintering aid (I) used for forming the base material, the sintering aid (II) used for forming the filtration membrane, and the sealant is more preferably a sintering aid. Alkali component content (% by mass) of (I)
Is x, the value of the alkali component content (% by mass) of the sintering aid (II) is y, and the value of the alkali component content (% by mass) of the sealant is z, -3.0. ≦ y−z ≦ + 3.
0, preferably −2.8 ≦ yz ≦ + 2.8, more preferably −2.5 ≦ yz ≦ + 2.5, and −
3.0 ≦ x−z ≦ + 3.0, preferably −2.8 ≦ x−
z ≦ + 2.8, more preferably −2.5 ≦ x−z ≦ +
Sintering aid (I), sintering aid (II) so as to be 2.5
And selecting a sealant. This suppresses any peeling between the filtration membrane and the seal portion and between the base material and the seal portion.

The most preferable material of the above three materials is the same composition of the three materials, a material which is not fritted as the sintering agent (I), and the sintering agent (II) and the sealing agent are used. Is to use a fritted material. Thereby, the base material can be fired and fired at a sufficiently high temperature, and the subsequent firing for forming the filtration membrane and the seal portion can be performed at a low temperature, and the problem of separation at each interface is sufficiently suppressed. You.

Hereinafter, the present invention will be described in more detail.
As illustrated in FIGS. 1 and 2, the ceramic membrane filter according to the present invention includes at least a substrate 1, a filtration membrane 2, and a seal part 3 as constituent members.

The substrate 1 is a member having a function as a support for the filtration membrane 2, and is preferably a ceramic porous body, preferably a porous body having an average pore diameter of 5 to 30 μm. The preferred shape of the substrate 1 is a tube shape having a single flow passage, a honeycomb shape having a plurality of parallel flow passages, or a monolith shape. The base material 1 is formed by sintering at least the aggregate and the sintering aid (I). For example, the aggregate and the sintering aid (I) are combined with a molding aid such as an organic binder and, if necessary, the surface activity. The clay obtained by adding and kneading the agent and the like is extruded into a honeycomb shape or the like, dried, and then fired to be formed. The firing temperature is preferably from 1200 to 1550 ° C, and the firing time at the highest temperature is preferably from 1 to 2 hours.

The aggregate is a ceramic particle constituting a main component of the base material. For example, particles of alumina, mullite, cordierite, silicon carbide, silicon nitride, aluminum nitride, ceramic waste, and the like are preferable. It is appropriately selected so as to be suitable. The average particle size of the aggregate is preferably 5-
It is about 200 μm. Aggregate consists of aggregate and sintering aid (I)
Is preferably contained in an amount of 65 to 90% by mass, and the sintering aid (I) is preferably contained in an amount of 10 to 35% by mass based on the total amount of

The filtration membrane 2 is a member for securing the filtration function of the ceramic membrane filter, and is a ceramic porous body formed on the substrate 1, preferably smaller than the average pore diameter of the substrate 1. It is a porous body having an average pore diameter. The filtration membrane 2 is formed by applying a raw material containing ceramic particles and preferably a sintering aid (II) to the base material 1 and firing the raw material. And the like, and an organic binder, a pH adjuster, a surfactant, an antifoaming agent, and the like are added as necessary. It is applied to the inner surface of the road, dried, fired and formed. The firing temperature is preferably 900 to 1100
° C and the time for the maximum temperature is preferably 1 hour.
In the present invention, the “filtration membrane applied and baked on the substrate” refers to the case where the filtration membrane 2 is directly applied to the surface of the substrate 1 as shown in FIG. Thus, both cases where the filtration membrane 2 is applied onto the substrate 1 via the intermediate layer 5 are included.

In the present invention, the same material as the above-mentioned aggregate can be used for the ceramic particles used to form the filtration membrane, but the preferred average particle size is about 0.1 to 5 μm. By selecting a smaller particle size, the pore size after firing becomes smaller. Therefore, the particle size is appropriately selected so as to have an appropriate pore size according to the purpose of filtration. The ceramic particles are preferably contained in an amount of 85 to 95% by mass based on the total of the ceramic particles and the sintering aid, and the sintering aid is preferably contained in an amount of 5 to 15% by mass.

When the ceramic membrane filter includes an intermediate layer 5 between the filtration membrane 2 and the substrate 1 as shown in FIG. 2, the intermediate layer 5 is preferably a ceramic porous body. It can be formed by the same method as that of the filtration membrane 2 using the same material as described above. In this case, the average pore diameter of the intermediate layer 5 is preferably formed to be larger than the average pore diameter of the filtration membrane 2. Therefore, the preferred average particle size of the ceramic particles used to form the intermediate layer 5 is about 0.1 to 5 μm, and more preferably the average particle size is larger than the average particle size of the ceramic particles used in the filtration membrane 2. Ceramic particles of a diameter are selected. That is, by this selection, the average pore diameter becomes smaller in the order of the base material, the intermediate layer, and the filtration membrane, and it is possible to maintain a good balance between the filtration performance and the processing capacity. When the intermediate layer is composed of two or more layers, the intermediate layer is preferably formed so that the average pore diameter gradually decreases from the substrate side toward the filtration membrane side.

The seal portion 3 is a member for preventing the fluid to be treated from entering the inside of the substrate 1 from the surface of the substrate 1, and includes a portion where the substrate 1 may come into contact with the fluid to be treated. A part of the filtration membrane 2 in the vicinity is covered. 1 and 2
In the embodiment, it is preferable that the end of the base material 1 and the filtration membrane 2 near the end of the base material 1 are covered with the seal portion 3.
The seal portion 3 is, for example, a portion that needs to be sealed,
For example, it is formed by applying a sealant to an end portion of the base material 1 and the vicinity thereof, drying the sealant, and then firing. The firing temperature is preferably 900 to 1100 ° C., and the firing time at the highest temperature is preferably 1 hour.

[0035]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. In the examples and comparative examples, a honeycomb-shaped ceramic membrane filter provided with one intermediate layer shown in FIG. 2 was produced.

The following materials were used in Examples and Comparative Examples. Aggregate: Alumina abrasive having an average particle diameter of 80 μm Ceramic particles 1: Fine alumina having an average particle diameter of 2.0 μm (for the middle layer of the filtration membrane) Ceramic particles 2: Fine alumina having an average particle diameter of 0.3 μm (for the filtration membrane) Sintering aid or sealant Material 1: Material obtained by pulverizing and mixing potassium feldspar and kaolin
Average particle size 0.8 μm Material 2: Kaolin Average particle size, 0.5 μm Material 3: Glaze for ceramics Average particle size, 0.6 μm Material 4: Melt material 3 at 1350 ° C., 0.8 μm after cooling
Material 5: Borosilicate frit glaze (fritted glaze) Material 6: Zirconia-containing borosilicate frit glaze (fritted glaze)

The compositions of the materials 1 to 6 were measured under the following measurement conditions. The results are shown in Table 1. Measurement conditions: The sample was pre-burned at 900 ° C. to decompose and scatter organic substances, water of crystallization, and carbonates, and then quantitative X-ray fluorescence analysis was performed.

[0038]

[Table 1]

Example 1 Based on the total weight of the aggregate and the sintering aid (I), 85% by weight of the aggregate, 15% by weight of the material 1 as the sintering aid (I), and the sum of these 4.5 parts by mass of methylsemellose and 1.0 part by mass of a surfactant were mixed with respect to 100 parts by mass to extrude a honeycomb-shaped substrate having a plurality of flow passages. After the molded body is dried, 1500 ° C.
For 2 hours to obtain a substrate 1 having an average pore diameter of 15 μm. Next, 90% by mass of the ceramic particles 1 and 10% by mass of the material 4 as a sintering aid are mixed based on the total mass of the ceramic particles 1 and the sintering aid.
A coating solution for an intermediate layer obtained by adding 0.6 parts by mass of an organic binder CMC (carboxymethyl cellulose) as a filtration resistance material to 100 parts by mass of a slurry in which 70 parts by mass of water is added to 0 parts by mass is added. Then, the inner surface of the flow passage of the base material was coated by a filtration method with a thickness of 200 μm, dried, and then baked at 1050 ° C. for 1 hour to form the intermediate layer 5. Furthermore, 90% by mass of the ceramic particles 2 with respect to 100% by mass of the total of the ceramic particles 2 and the sintering aid (II).
And 10 parts by mass of a material 4 as a sintering aid (II), and 100 parts by mass of a slurry in which 90 parts by mass of water was added to 10 parts by mass of the mixture, and 0.4 part as a filtration resistance material was added. A filtration membrane coating solution obtained by adding an acrylate copolymer as an organic binder in parts by mass is coated on the surface of the intermediate layer 5 to a thickness of 20 μm, dried, and then baked at 1050 ° C. for 1 hour and filtered. Film 2 was formed.
Finally, the material 4 is coated as a sealant so as to cover the end of the substrate 1 and the end of the intermediate layer 5 and the filter membrane in the vicinity of the end, and is fired at 1050 ° C. for 1 hour to form a seal. 3 was formed, and a ceramic membrane filter was obtained.

Example 2 A substrate 1 was prepared in the same manner as in Example 1, and 10% by mass of a material 5 finely pulverized to the same particle diameter as the ceramic particles 1 was used as a sintering aid. The intermediate layer 5 was formed in the same manner as in Example 1 except that the firing was performed at 950 ° C. for 1 hour. Further, as a sintering aid (II), 1 finely pulverized to the same particle size as the ceramic particles 2
Filtration membrane 2 was formed in the same manner as in Example 1, except that 0% by mass of material 5 was used and calcined at 950 ° C. for 1 hour. Finally, the material 5 was coated in the same manner as in Example 1, and baked at 950 ° C. for 1 hour to form a seal portion 3 to obtain a ceramic membrane filter.

Example 3 A material 1 was used in the same manner as in Example 1 except that Material 3 was used as a sintering aid (I) and was fired at 1250 ° C. for 1 hour.
was gotten. Next, material 4 was used as a sintering aid,
An intermediate layer 5 was formed in the same manner as in Example 1 except that the firing was performed at 100 ° C. for 1 hour. Next, material 4 as a sintering aid
Was used, and a filtration membrane 2 was formed in the same manner as in Example 1 except that it was fired at 1100 ° C. for 1 hour. Finally, material 4 is coated in the same manner as in Example 1 and
For 1 hour to form a seal portion 3 to obtain a ceramic membrane filter.

Example 4 A substrate 1 was formed in the same manner as in Example 1. Next, the intermediate layer 5 was formed in the same manner as in Example 1 except that the material 2 was used as a sintering aid and was fired at 1400 ° C. for 1 hour. Furthermore, 1350 ° C. without using the sintering aid (II)
The filtration membrane 2 was formed in the same manner as in Example 1 except that the baking was performed for 1 hour. Finally, the material 6 was coated in the same manner as in Example 1, and baked at 950 ° C. for 1 hour to form the seal portion 3, thereby obtaining a ceramic membrane filter.

Comparative Example 1 A substrate 1 was formed in the same manner as in Example 1. Next, the intermediate layer 5 was formed in the same manner as in Example 1 except that the material 2 was used as a sintering aid and was fired at 1400 ° C. for 1 hour. Further, except that the sintering was performed at 1350 ° C. for 1 hour without using the sintering aid (II), the filtration membrane 2 was prepared in the same manner as in Example 1.
Was formed. Finally, the material 3 was coated in the same manner as in Example 1, and baked at 1300 ° C. for 1 hour to form the seal portion 3, thereby obtaining a ceramic membrane filter.

Comparative Example 2 A substrate 1 was formed in the same manner as in Example 1. Next, the intermediate layer 5 was formed in the same manner as in Example 1 except that the material 2 was used as a sintering aid and was fired at 1400 ° C. for 1 hour. Further, except that the sintering was performed at 1350 ° C. for 1 hour without using the sintering aid (II), the filtration membrane 2 was prepared in the same manner as in Example 1.
Was formed. Finally, the material 5 was coated in the same manner as in Example 1, and baked at 950 ° C. for 1 hour to form the seal portion 3, thereby obtaining a ceramic membrane filter.

Forced Degradation Peeling Test of Each Ceramic Membrane Filter The ceramic membrane filters obtained in Examples 1 to 3 and Comparative Example 1 were immersed in a 2% aqueous sodium hydroxide solution at 90 ° C. for 16 hours.
After immersion for 8 hours, the presence or absence of peeling between the base material and the seal portion and between the filtration membrane and the seal portion was visually evaluated. Peeling was not confirmed in the filter obtained in Example 3 between the substrate and the seal portion, but peeling was confirmed in all other filters. Examples 1 to 3 between the filtration membrane and the sealing portion
No peeling was observed in the filter of No. 3;
Peeling was confirmed in the filter.

The ceramic membrane filters obtained in Examples 1 to 3 and Comparative Example 2 were placed in an aqueous citric acid solution having a pH of 3
After being immersed at 0 ° C. for 96 hours, the presence or absence of peeling between the base material and the sealing portion and between the filtration membrane and the sealing portion was visually evaluated. Peeling was not confirmed in the filter obtained in Example 3 between the substrate and the seal portion, but peeling was confirmed in all other filters. Regarding the space between the filtration membrane and the seal portion, the filters of Examples 1 to 3 were not peeled off,
Peeling was confirmed in the filter of Comparative Example 2.

The ceramic membrane filters obtained in Examples 1 to 4 were immersed in an aqueous sodium hypochlorite solution containing 3000 ppm of chlorine at 30 ° C. for 120 hours. The presence or absence of peeling was visually evaluated. Examples 1 and 4 between the base material and the seal portion
No peeling was confirmed in the filters of Examples 2 and 3, but peeling was confirmed in the filters of Examples 2 and 3. Peeling was not confirmed in the filters of Examples 1 to 3 between the filtration membrane and the seal portion, but peeling was confirmed in the filter of Example 4.

Table 2 shows the sintering aids and sealing agents and sintering temperatures used in each of the examples and comparative examples. Here, the sealant 4 of Example 1 and Example 3 and the sealant 3 of Comparative Example 1 have the same composition, and the sealant 4 is obtained by fritting the sealant 3. By fritting, the firing temperature of the sealant could be reduced from 1300 ° C to 1050 ° C.

[0049]

[Table 2]

According to the composition analysis (Table 1) of the sintering aid and the sealant used in each of Examples and Comparative Examples, K
Table 3 shows the sum of the contents of the components obtained as ₂ O and Na ₂ O, their difference, and the results of the forced aging peel test. The value (xz) obtained by subtracting the value (z) of the content of the alkali component contained in the sealant from the value (x) of the content of the alkali component contained in the sintering aid (I), or From the value (y) of the content of the alkali component contained in the agent (II), the value (z) of the content of the alkali component contained in the sealing agent
When the value (yz) obtained by subtracting is 0 or -2.3, no peeling occurred, and when this value was lower than -4, peeling occurred.

[0051]

[Table 3]

The relative concentrations of potassium and sodium in the cross section near the interface between the filtration membrane and the seal portion of the filters obtained in Comparative Example 2 and Example 3 were measured by using a scanning electron microscope (SE).
M) Measured with an attached energy dispersive X-ray analyzer. In the case of the filter of Comparative Example 2, the relative concentrations of sodium and potassium were extremely high at the interface between the filtration membrane and the seal portion, and the concentrations of sodium and potassium at the interface were both twice or more the concentration of the seal portion. On the other hand, Example 3
In the filter of No. 1, the phenomenon of increasing the concentration of sodium and potassium at the interface between the filtration membrane and the seal portion as seen in Comparative Example 1 was not observed.

[0053]

As described above, according to the present invention, the difference between the alkali content of the sintering aid (I) for the base material and the alkali content of the sealing agent, and the alkali sintering aid (II) for the filtration membrane. The difference between the content and the alkali content of the sealant is -3.0 to +3.0.
When the cleaning was performed using an aqueous solution of an alkaline substance, citric acid, sodium hypochlorite, or the like, a ceramic membrane filter in which the base material and the sealing portion and the filtration film and the sealing portion were not easily separated was obtained. Further, by using the frit as the sintering aid (II) and / or the sealant, it was possible to manufacture a ceramic membrane filter at a low firing temperature while maintaining the above effects.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a state in which a ceramic membrane filter according to an embodiment of the present invention is mounted on a housing.

FIG. 2 is a schematic cross-sectional view of a ceramic membrane filter showing another embodiment of the present invention.

FIG. 3 is a schematic sectional view showing a state in which a ceramic membrane filter having no seal portion is mounted on a housing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base material, 2 ... Filtration membrane, 3 ... Seal part, 5 ... Intermediate layer, 1
1 ... O-ring, 12 ... Housing.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C04B 35/18 C04B 38/00 303Z 38/00 303 41/85 C 41/85 35/18 Z F term ( 4D006 GA02 GA41 HA80 JA22A JB01 MA04 MA09 MC03X MC90 NA39 NA50 PA01 4D019 AA01 AA03 BA05 BB06 BC12 CA01 CB06 4G019 FA01 FA12 LA07 4G030 AA17 AA35 AA36 AA37 BA32 CA07 CA09 CA10 GA11 GA19 GA32 HA05 HA15

Claims (5)

[Claims] 1. A base material obtained by firing a raw material containing at least aggregate, and a filtration membrane obtained by applying and firing a raw material containing at least ceramic particles and a sintering aid (II) on the base material. And a seal portion in which a raw material containing at least a sealing agent is applied to a part of the base material and a part of the filtration membrane and fired, and the sintering aid (II )), The value of the alkali component content (% by mass) in the sealing agent is y, and the value of the alkali component content (% by mass) in the sealant is z: −3.0 ≦ y−z ≦ + 3.0. A ceramic membrane filter characterized by the following relationship: 2. A base material obtained by firing a raw material containing at least aggregate and a sintering aid (I), and a filtration membrane obtained by applying a raw material containing at least ceramic particles on the base material and firing the base material. A ceramic membrane filter, comprising: a seal portion in which a raw material containing at least a sealing agent is applied to a part of the base material and a part of the filtration membrane and fired.
Alkali component content (% by mass) in the sintering aid (I)
Where x is the value of x and z is the value of the alkali component content (mass%) in the sealant, -3.0≤xz≤ + 3.0. filter. 3. A base material obtained by firing a raw material containing at least aggregate and a sintering aid (I), and a raw material containing at least ceramic particles and a sintering aid (II) are applied on the base material. And a fired and fired filter membrane, and a seal portion formed by firing a raw material containing at least a sealant applied to a part of the base material and a part of the filter membrane and fired. The value of the alkali component content (% by mass) in the sintering aid (I) is x, and the value of the sintering aid (II) is
When the value of the alkali component content (% by mass) in the sealant is y and the value of the alkali component content (% by mass) in the sealant is z, -3.0 ≦ y−z ≦ + 3.0 A ceramic membrane filter characterized by a relationship of -3.0 ≦ x−z ≦ + 3.0. 4. The ceramic membrane filter according to claim 1, wherein the sintering aid (II) contains a frit. 5. The ceramic membrane filter according to claim 1, wherein the sealant contains a frit.