JPWO2016051921A1 - Membrane structure and manufacturing method thereof - Google Patents

Abstract

The membrane structure (100) includes a porous base body (210) and a first fluororesin layer (223). The substrate body (210) includes a first end surface (S1), a second end surface (S2), and a plurality of through holes (TH1) penetrating from the first end surface (S1) to the second end surface (S2). Have. The first fluororesin layer (223) covers the first end surface (S1) of the base body (210).

Description

  The present invention relates to a membrane structure and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, a membrane structure including a base body having a plurality of through holes, a separation membrane formed on the inner surface of the through holes, and a glass seal covering an end surface of the base body is known. The glass seal is provided to prevent the mixed solution to be filtered from entering the base body.

  Here, for the purpose of improving the heat resistance of the glass seal, a method of dispersing ceramic particles in the glass seal has been proposed (see Patent Document 1).

International Publication No. 2012/008476

  However, according to the method of Patent Document 1, if a crack occurs in the glass seal for some reason, it is difficult to suppress the intrusion of the mixed solution. Therefore, there is a demand for suppressing the intrusion of the mixed solution even if a crack occurs in the glass seal. Furthermore, since the glass seal may be cracked or peeled off, there is also a demand for suppressing the intrusion of the mixed solution without providing the glass seal.

  This invention is made | formed in view of the above-mentioned situation, and it aims at providing the film | membrane structure which can suppress the penetration | invasion to the base-material main body of a mixed solution.

  The membrane structure according to the present invention includes a porous base body and a fluororesin layer. The base body has a first end surface, a second end surface, and a plurality of through holes penetrating from the first end surface to the second end surface. The fluororesin layer covers the first end face.

  ADVANTAGE OF THE INVENTION According to this invention, the film | membrane structure which can suppress the penetration | invasion to the base-material main body of a mixed solution, and its manufacturing method can be provided.

Perspective view of membrane structure Partial enlarged view of the AA cross section of FIG. Partial enlarged view of the AA cross section of FIG.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  In the following embodiments, the “monolith” means a shape having a plurality of through holes formed in the longitudinal direction, and is a concept including a honeycomb shape.

(Configuration of membrane structure 100)
FIG. 1 is a perspective view of the membrane structure 100. FIG. 2 is a partially enlarged view of the AA cross section of FIG.

  The membrane structure 100 includes a monolith type substrate 200 and a separation membrane 300. The monolith type substrate 200 has a substrate body 210, a first seal part 220, and a second seal part 230.

  The base body 210 is a porous body. The base body 210 is formed in a cylindrical shape. The length of the base body 210 in the longitudinal direction can be 150 to 2000 mm, and the diameter of the base body 210 in the short direction can be 30 to 220 mm, but is not limited thereto.

  As shown in FIG. 2, the base body 210 has a first end surface S1, a second end surface S2, a side surface S3, and a plurality of through holes TH1. The first end surface S1 is provided opposite to the second end surface S2. The side surface S3 continues to the outer edges of the first end surface S1 and the second end surface S2. The plurality of through holes TH1 penetrate through the inside of the base body 210 so as to continue from the first end surface S1 to the second end surface S2. The cross-sectional shape of the through hole TH1 is circular, but is not limited thereto. The inner diameter of the through hole TH1 can be 1 to 5 mm.

  As shown in FIG. 2, the substrate main body 210 includes a base body 211, a first support film 212, and a second support film 213.

The base 211 is formed in a cylindrical shape. A plurality of through holes TH2 are formed in the base 211. The substrate 211 is made of a porous material. As the porous material of the substrate 211, ceramics, metal, resin, or the like can be used, and a porous ceramic material is particularly preferable. As aggregate particles of the porous ceramic material, alumina (Al ₂ O ₃ ), titania (TiO ₂ ), mullite (Al ₂ O ₃ .SiO ₂ ), cerven and cordierite (Mg ₂ Al ₄ Si ₅ O ₁₈ ) In view of easy availability, stability of clay, and corrosion resistance, alumina is particularly preferable. The substrate 211 may include an inorganic binder in addition to the porous material. As the inorganic binder, at least one of titania, mullite, easily sinterable alumina, silica, glass frit, clay mineral, and easily sinterable cordierite can be used. The porosity of the substrate 211 can be 25% to 50%. The average pore diameter of the substrate 211 can be 5 μm to 25 μm. The average particle diameter of the porous material constituting the substrate 211 can be 5 μm to 100 μm. The average pore diameter of the substrate 211 can be measured with a mercury porosimeter. In the present embodiment, the “average particle diameter” is a value obtained by arithmetically averaging the maximum diameters of 30 measurement target particles measured by cross-sectional microstructure observation using an SEM (Scanning Electron Microscope).

  The first support film 212 is formed on the inner surface of the base body 211 (through hole TH2). The first support film 212 is formed in a cylindrical shape. The first support film 212 is made of a porous ceramic material similar to that of the base body 211. The thickness of the first support film 212 in the direction perpendicular to the central axis of the through hole TH1 (hereinafter referred to as the radial direction) can be 30 μm to 300 μm. The porosity of the first support film 212 can be 20% to 60%. The average pore diameter of the first support membrane 212 may be smaller than the average pore diameter of the substrate 211, and can be, for example, 0.005 μm to 2 μm. The average pore diameter of the first support membrane 212 can be measured with a palm porometer.

  The second support film 213 is formed on the inner surface of the first support film 212. The second support film 213 is formed in a cylindrical shape. The second support film 213 is made of a porous ceramic material similar to that of the base body 211. The thickness of the second support film 213 in the radial direction can be 1 μm to 50 μm. The porosity of the second support film 213 can be 20% to 60%. The average pore diameter of the second support membrane 213 may be smaller than the average pore diameter of the first support membrane 212, and may be, for example, 0.001 μm to 5 μm. The average pore diameter of the second support membrane 213 can be measured with a palm porometer.

  As shown in FIG. 2, the first seal portion 220 includes a first glass seal 221, a first primer layer 222, and a first fluororesin layer 223.

  The first glass seal 221 covers the entire first end surface S1 and a part of the side surface S3 of the base body 210. The first glass seal 221 suppresses a mixed fluid (for example, an organic solvent) that is a filtration target flowing into the cell C described later from entering the base body 210 from the first end surface S1. The first glass seal 221 is formed so as not to block the inlet of the cell C. As a material constituting the first glass seal 221, glass that does not allow the mixed fluid to permeate can be used, and alkali-free glass that can suppress diffusion of alkali components is particularly suitable. The thickness of the first glass seal 221 in the direction perpendicular to the first end face S1 (that is, the longitudinal direction) can be 10 μm to 1000 μm.

  The first primer layer 222 is formed on the first glass seal 221 and covers the first glass seal 221. The first primer layer 222 is interposed between the first glass seal 221 and the first fluororesin layer 223. The first primer layer 222 preferably covers the vicinity of the boundary between the first glass seal 221 and the separation membrane 300.

  The first primer layer 222 has a function of improving the adhesion of the first fluororesin layer 223 to the first glass seal 221. The adhesive force between the first primer layer 222 and the first glass seal 221 is larger than the adhesive force between the first fluororesin layer 223 and the first glass seal 221. Similarly, the adhesive force between the first primer layer 222 and the first fluororesin layer 223 is larger than the adhesive force between the first fluororesin layer 223 and the first glass seal 221. The first primer layer 222 is composed of a fluororesin and an adhesive component. Examples of fluororesins include PTFE (Poly Tetra Fluoro Ethylene Tetrafluoride Ethylene), PFA (Tetra Fluoro Ethylene-Perfluoro Alkyl Vinyl Ether Copolymer) and FEP (Fluorinated Ethylene Propylene Copolymer; At least one of tetrafluoroethylene / hexafluoropropylene copolymer) or a copolymer containing these basic structures can be used. A commercially available Teflon primer agent can be used as the adhesive component. The thickness of the first primer layer 222 in the direction perpendicular to the first end surface S1 can be 1 μm to 100 μm.

  The first fluororesin layer 223 is formed on the first primer layer 222 and covers the first glass seal 221. The first fluororesin layer 223 covers the entire first end surface S1 and a part of the side surface S3 with the first glass seal 221 and the first primer layer 22 sandwiched therebetween. The first fluororesin layer 223 preferably covers the vicinity of the boundary between the first glass seal 221 and the separation membrane 300. However, the first fluororesin layer 223 is formed so as not to block the inlet of the cell C. The first fluororesin layer 223 prevents the mixed fluid from entering the base body 210 from the first end surface S1, and protects the first glass seal 221.

  The first fluororesin layer 223 is made of a fluororesin. As the fluorine tree, at least one of PTFE, PFA and FEP, or a copolymer containing these basic structures can be used. PFA is suitable as a sealing material because it has higher chemical corrosion resistance than FEP. PTFE is particularly suitable as a sealing material because it has a lower melting point than PFA and can be constructed at a low temperature. The thickness of the first fluororesin layer 223 in the direction perpendicular to the first end face S1 can be 1 μm to 2000 μm, and preferably 100 μm or more.

  As shown in FIG. 2, the second seal part 230 includes a second glass seal 231, a second primer layer 232, and a second fluororesin layer 233.

  The second glass seal 231 covers the entire second end surface S2 of the base body 210 and a part of the side surface S3. The second glass seal 231 prevents the mixed fluid flowing into the cell C from entering the base body 210 from the second end surface S2. The second glass seal 231 is formed so as not to block the outlet of the cell C. The second glass seal 231 is made of the same material as the first glass seal 221. The thickness of the second glass seal 231 in the direction perpendicular to the second end surface S2 (that is, the longitudinal direction) can be 10 μm to 1000 μm.

  The second primer layer 232 is formed on the second glass seal 231 and covers the second glass seal 231. The second primer layer 232 is interposed between the second glass seal 231 and the second fluororesin layer 233. The second primer layer 232 preferably covers the vicinity of the boundary between the first glass seal 221 and the separation membrane 300.

  The second primer layer 232 has a function of improving the adhesion of the second fluororesin layer 233 to the second glass seal 231. The adhesive force between the second primer layer 232 and the second glass seal 231 is larger than the adhesive force between the second fluororesin layer 233 and the second glass seal 231. Similarly, the adhesive force between the second primer layer 232 and the second fluororesin layer 233 is greater than the adhesive force between the second fluororesin layer 233 and the second glass seal 231. The second primer layer 232 is made of the same material as the first primer layer 222. The thickness of the second primer layer 232 in the direction perpendicular to the second end surface S2 can be 1 μm to 100 μm.

  The second fluororesin layer 233 is formed on the second primer layer 232 and covers the second glass seal 231. The second fluororesin layer 233 covers the entire surface of the second end surface S2 and part of the side surface S3 with the second glass seal 231 and the first primer layer 22 sandwiched therebetween. The second fluororesin layer 233 preferably covers the vicinity of the boundary between the first glass seal 221 and the separation membrane 300. However, the second fluororesin layer 233 is formed so as not to block the inlet of the cell C. The second fluororesin layer 233 prevents the mixed fluid from entering the base body 210 from the second end surface S2, and protects the second glass seal 231.

  The second fluororesin layer 233 is made of the same material as the first fluororesin layer 222. The thickness of the second fluororesin layer 233 in the direction perpendicular to the second end surface S2 can be 10 μm to 2000 μm, and preferably 100 μm or more.

  The separation membrane 300 is formed on the inner surface of the through hole TH1 (in the present embodiment, the second support membrane 213). The separation membrane 300 is formed in a cylindrical shape. The space inside the separation membrane 300 is a cell C for circulating the mixed fluid. The inner diameter of the cell C in the radial direction is not particularly limited, but can be, for example, 0.5 mm to 3.5 mm. The thickness of the separation membrane 300 in the radial direction is not particularly limited, but is preferably 5 μm or less, and more preferably 3 μm or less. The separation membrane 300 can be made of an inorganic material or a metal. For example, a zeolite membrane, a carbon membrane, and a silica membrane are suitable as the separation membrane 300 in the separation or concentration of the mixed liquid by the pervaporation operation or the vapor permeation operation. In addition, a solid-liquid separation by ultrafiltration operation such as water purification, nanofiltration operation, separation of macromolecules such as proteins, or virus separation, a UF membrane obtained by sintering nanoparticles prepared by a sol-gel method or the like Or a nano membrane is suitable as the separation membrane 300. When the separation membrane 300 is a zeolite membrane, a zeolite having a crystal structure such as LTA, MFI, MOR, FER, FAU, DDR, CHA, and BEA can be used.

(Manufacturing method of membrane structure 100)
First, a molded body of the base body 211 having a plurality of through holes TH2 is formed using a clay containing a porous material. As a method for forming the molded body of the substrate 211, a press molding method or a cast molding method can be used in addition to an extrusion molding method using a vacuum extrusion molding machine.

  Next, the base body 211 is formed by firing the molded body of the base body 211 (for example, 500 ° C. to 1500 ° C., 0.5 hour to 80 hours).

  Next, an organic binder, a pH adjuster, a surfactant, and the like are added to the porous material to prepare a first support film slurry.

  Next, a molded body of the first support film 212 is formed using the first support film slurry by a filtration method, a flow-down method, or the like. Specifically, the first support film 212 is formed on the inner surface of the through hole TH2 by sucking the first support film slurry to the through hole TH2 of the base body 211 by a pump from the side surface S3 of the base body 211. Deposit the body.

  Next, the first support film 212 is formed by firing the molded body of the first support film 212 (for example, 900 ° C. to 1450 ° C., 0.5 hour to 80 hours).

  Next, an organic binder, a pH adjuster, a surfactant, and the like are added to the porous material to prepare a second support film slurry.

  Next, a molded body of the second support film 213 is formed using the second support film slurry by a filtration method, a flow-down method, or the like. Specifically, the second support film 213 is formed on the first support film 212 by supplying the second support film slurry to the inside of the first support film 212 by pumping from the side surface S3 of the substrate 211. Deposit the body.

  Next, the second support film 213 is formed by firing the molded body of the second support film 213 (for example, 900 ° C. to 1450 ° C., 0.5 hour to 80 hours). Thus, the base body 210 having a plurality of through holes TH1 is completed.

  Next, a glass frit, water, an organic binder, and the like are mixed to prepare a glass seal slurry.

  Next, a molded body of the first glass seal 221 and the second glass seal 231 is formed by applying a slurry for glass seal to the first end surface S1 and the second end surface S2 of the base body 210.

  Next, the first glass seal 221 and the second glass seal 221 and the second glass seal 231 are fired (for example, 700 ° C. to 1200 ° C., 0.5 hours to 80 hours), thereby forming the first glass seal 221 and the second glass seal. 231 is formed.

  Next, the separation membrane 300 is formed on the inner surfaces of the plurality of through holes TH1. As a method for forming the separation membrane 300, an appropriate method according to the type of the separation membrane 300 may be used. For example, when a DDR type zeolite membrane is formed as the separation membrane 300, a seeding step by a flow-down method, a hydrothermal synthesis step of a sol, and a heating step for removing the structure directing agent are sequentially performed.

  Next, a mixture of a fluororesin and an adhesive component is applied to the surfaces of the first glass seal 221 and the second glass seal 231 and dried. Thereby, a molded body of the first primer layer 222 and the second primer layer 232 is formed. The molded body of the first primer layer 222 and the second primer layer 232 may cover the side surface S3 of the base body 210 and a part of the separation membrane 300.

  Next, a fluororesin is applied to the surface of the molded body of the first primer layer 222 and the second primer layer 232 and baked under predetermined conditions (for example, 280 ° C. to 380 ° C., 0.1 hour to 2 hours). As a result, the first and second fluororesin layers 223 and 233 and the first and second primer layers 222 and 232 are formed. The first and second fluororesin layers 223 and 233 can be formed by PFA coating, PFA powder coating, FEP dispersion coating, or PTFE dispersion coating. When the first and second fluororesin layers 223 and 233 are formed by PFA coating or PFA powder coating, a coarse fluororesin particle having a particle size of 25 μm or more is used for at least a part of the fluororesin substrate. Film defects due to penetration into the main body 210 can be suppressed.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.

  (A) In the above embodiment, the monolithic substrate 200 includes the substrate body 210, the first seal portion 220, and the second seal portion 230. However, the first seal portion 220 and the second seal portion are included. It is not necessary to have at least one of 230.

  (B) In the above embodiment, the first seal portion 220 has the first primer layer 222. However, as shown in FIG. 3, the first seal portion 220 may not have the first primer layer 222. Similarly, the second seal portion 230 may not have the second primer layer 232.

  (C) In the said embodiment, although the 1st seal | sticker part 220 decided to have the 1st glass seal 221, it does not need to have the 1st glass seal 221 as shown in FIG. Similarly, the second seal portion 230 may not have the second glass seal 231. Thus, when each seal | sticker part does not have a glass seal, the separation membrane 300 can be utilized suitably as a water purification film | membrane which produces | generates purified water by filtering and refining water.

  (D) In the above embodiment, the base body 210 has the base 211, the first support film 212, and the second support film 213, but the first support film 212 and the second support film 213 It does not need to have at least one. When the base body 210 does not have the second support membrane 213, the separation membrane 300 is formed on the first support membrane 212. As shown in FIG. 3, when the base body 210 does not have the first support film 212 and the second support film 213, the separation film 300 is formed on the inner surface of the substrate 211.

  (E) In the above embodiment, the first and second glass seals 221, 231 → separation membrane 300 → first and second fluororesin layers 223, 233 are formed in this order, but the separation membrane 300 → first and The second glass seals 221 and 231 may be formed in the order of the first and second fluororesin layers 223 and 233, or the first and second glass seals 221 and 231 may be formed in the order of the first and second fluororesin layers 223 and 233. → The separation membrane 300 may be formed in this order.

  (F) In the above embodiment, the cross-sectional shape of the cell C is circular, but it may be elliptical, rectangular, or polygonal.

  (G) In the above embodiment, the membrane structure 100 includes the monolithic substrate 200 and the separation membrane 300, but may not include the separation membrane 300. When the membrane structure 100 does not include the separation membrane 300, the first support membrane 212 and the second support membrane 213 function as a separation membrane for solid-liquid separation by microfiltration operation for water purification.

  Examples of the present invention will be described below. However, the present invention is not limited to the examples described below.

(Production of sample No. 1 to No. 3)
First, by adding 20 parts by mass of a frit as a sintering aid to 100 parts by mass of alumina particles having an average particle diameter of 50 μm as aggregate particles, and further kneading by adding water, a dispersant and a thickener. I got dredged soil.

  Next, the molded clay was dried and fired (1250 ° C., 1 hour, temperature increase and temperature decrease rate 100 ° C./hour) to prepare a substrate. The dimensions of the substrate were 30 mm diameter x 30 mm length. In the substrate, 55 through holes were formed.

  Next, 14 parts by mass of frit as a sintering aid is added to 100 parts by mass of alumina particles having an average particle diameter of 3 μm as aggregate particles, and water, a dispersant and a thickener are further added and mixed. Thus, a slurry for the first support membrane was prepared. Next, a molded body of the first support film was formed on the inner peripheral surface of the through hole of the substrate by a filtration method using the first support film slurry. Next, the first support film was formed by firing the compact of the first support film in an electric furnace (950 ° C., 1 hour, temperature increase and temperature decrease rate 100 ° C./hour in an air atmosphere).

  Next, water, a dispersing agent, and a thickener were added to and mixed with titania particles having an average particle size of 0.5 μm as aggregate particles to prepare a second support membrane slurry. Next, a molded body of the second support film was formed on the inner peripheral surface of the first support film by a filtration method using the second support film slurry. Next, the second support film was formed by firing the compact of the second support film in an electric furnace (at atmospheric temperature, 950 ° C., 1 hour, temperature increase and temperature decrease rate 100 ° C./hour). In this way, a base body having a plurality of through holes was completed.

  Next, a glass frit, water, and an organic binder were mixed to prepare a glass seal slurry. Next, a glass seal slurry was applied to both end faces of the base body to form a set of glass seal compacts. Next, the set of glass seals was fired in an electric furnace (950 ° C., 1 hour, temperature increase and temperature decrease rate 100 ° C./hour in an air atmosphere) to form a set of glass seals.

  Next, sample no. In No. 3, a set of primer layers was formed by applying a mixture of a fluororesin and an adhesive component to the surface of the set of glass seals and drying. On the other hand, sample no. In Nos. 1 and 2, a set of primer layers was not formed.

  Next, sample no. In 2, a set of fluororesin layers (thickness 50 μm) was formed by applying and baking PFA on the surface of each set of glass seals. Similarly, sample no. In No. 3, a set of fluororesin layers (thickness 50 μm) was formed by applying and baking PFA on the surface of each set of primer layers. On the other hand, sample no. In No. 1, no fluororesin layer was formed. Thus, sample no. 1 is composed only of a glass seal. 2 is composed of a glass seal and a fluororesin layer. The seal part 3 is composed of a glass seal, a primer layer, and a fluororesin layer.

  As described above, sample no. 1-No. 3 was completed.

(Durability evaluation of seal part)
First, sample no. 1-No. 3 was immersed in an acetic acid aqueous solution (water concentration 50%) in a pressure vessel and sealed.

  Next, the pressure vessel is heated to 200 ° C., and taken out every 80 hours, 200 hours, 600 hours, 1000 hours, 1200 hours, and 1600 hours to check for cracks in the glass seal and peeling of the fluororesin layer. Observed. The presence or absence of cracks was determined by whether or not the dye applied to the surface of the seal portion had penetrated into the cracks. When the dye soaks into the crack, it is expected that the treatment liquid will permeate and leak even during dehydration separation. The observation results are summarized in Table 1.

  As shown in Table 1, sample No. 1 in which the glass seal was protected with a fluororesin layer. In Nos. 2 and 3, no cracks in the glass seal and peeling of the fluororesin layer were observed after 80 hours. On the other hand, sample no. In 1, the crack of the glass seal was observed after 80 hours. Therefore, it was confirmed that the glass seal could be prevented from cracking by protecting the glass seal with the fluororesin layer.

  In addition, sample no. In No. 3, no peeling of the fluororesin layer was observed even after 1000 hours had passed. Therefore, it was confirmed that peeling of the fluororesin layer can be suppressed by adhering the glass seal and the fluororesin layer with the primer layer.

(Production of sample Nos. 4 and 5)
Using the materials shown in Table 2, Sample No. 1 to 3 in the same process. Film structures according to 4 and 5 were produced. However, sample no. 4 and 5, the size of the substrate is 30 mm diameter × 160 mm length, a DDR type zeolite membrane is formed on the inner surface of the second support membrane, and then PFA is applied onto the glass seal and baked to obtain a fluororesin. A layer (thickness 50 μm) was formed.

  (Evaluation of influence on separation performance of fluororesin layer)

  First, while supplying the mixed fluid shown in Table 2 to the cell of each sample, it was sucked from the side by a pump for 1.5 hours, and then the permeate was collected for 0.5 hours. Thereafter, the permeation speed was calculated from the amount of liquid permeated through each sample, and the separation coefficient α was calculated based on the following equation (1).

  Separation factor α = ([stock solution water molarity] / [stock solution ethanol molarity]) / ([permeate water molarity] / [permeate ethanol molarity]) (1)

  Furthermore, each sample after the initial performance was measured was sealed in a pressure vessel together with a small amount of water, and heated at 170 ° C. for 200 hours, so that each sample was exposed to water vapor and deteriorated. After being exposed to water vapor, each sample was taken out and dried. While supplying the mixed fluid shown in Table 2 to the cell of each sample, the sample was sucked from the side by a pump for 1.5 hours, and then the permeate was collected for 0.5 hour. . Thereafter, the permeation speed was calculated from the amount of liquid permeated through each sample, and the separation coefficient α was calculated based on the above formula (1).

  As shown in Table 2, sample No. 1 provided with a fluororesin layer was used. The permeation rate and the separation factor α of Sample No. It was equivalent to 4. Thereby, it was confirmed that the presence or absence of the fluororesin layer does not affect the initial separation performance. Moreover, when the performance after deterioration is compared, sample No. provided with a fluororesin layer is obtained. 5 confirmed that there was little deterioration.

  Sample No. provided with a fluororesin layer. No. 5 was able to maintain the permeation rate and separation factor α even after exposure to water vapor. Therefore, it was confirmed that the function of the seal portion can be maintained by providing the fluororesin layer.

(Easy fabrication of fluororesin layer)
First, a fluororesin layer slurry was prepared using the materials shown in Table 3. As shown in Table 3, sample no. No. 6 uses fluororesin particles having a particle size of 5 μm. 7 used fluororesin particles having a particle size of 25 μm. In 8 to 11, fluororesin particles having a particle diameter of 5 μm and a particle diameter of 25 μm were used at a weight ratio of 1: 1.

  Next, the fluororesin layer slurry was directly applied to the porous substrate and baked under the heat treatment conditions shown in Table 3.

  Subsequently, the number of defects in the fluororesin layer was observed by a dyeing test. The number of defects was determined by the number of pinholes infiltrated with the dye applied to the seal surface. Table 3 shows the determination results of the number of defects.

  As shown in Table 3, when the fluororesin layer is directly applied to the porous base body and baked, sample No. 1 using fluororesin particles having a particle diameter of 25 μm larger than the pore diameter of the base body is used. In 7-11, the defect of the fluororesin layer was able to be suppressed. This is because the fluororesin particles can be prevented from soaking into the base body.

(Evaluation of chemical resistance of seals)
Sample No. 1 to 3 in the same process. Film structures according to 12-14 were prepared. However, sample no. In No. 13, a fluororesin layer was directly formed on both end faces of the base body without forming glass seals on both end faces of the base body. Sample No. In No. 14, a primer layer and a fluororesin layer were sequentially formed on both end faces of the base body without forming glass seals on both end faces of the base body. Sample No. 13 and 14, sample no. A fluororesin layer was formed using the same material as in No. 11.

  Next, since a chemical solution is generally washed with an acid / alkaline in water supply applications, a chemical solution resistance cycle test was performed for each sample to evaluate the chemical solution resistance against the acid / alkali. In the chemical resistance cycle test, the seal part of each sample is immersed in sulfuric acid (PH1.8) in an autoclave and heated (150 ° C., 50 hours), the process of cleaning and drying the seal part, The process of immersing the seal portion in NaOH (2% aqueous solution) in an autoclave and heating (150 ° C., 50 hours) was taken as one cycle. Sample No. In No. 12, a chemical resistance cycle test was performed for one cycle. In Nos. 13 and 14, the chemical resistance cycle test was performed for 2 cycles.

  Each time one cycle was completed, the seal portion of each sample was observed to confirm the presence or absence of peeling at the seal portion.

  As shown in Table 4, sample No. protected with a fluororesin layer was used. In Nos. 13 and 14, peeling did not occur at the seal part even after the chemical resistance cycle test was carried out for 2 cycles. On the other hand, sample no. No. 12, peeling occurred after one cycle of the chemical resistance cycle test. Therefore, it was confirmed that the durability of the seal portion can be improved by providing the fluororesin layer regardless of the presence or absence of the glass seal.

DESCRIPTION OF SYMBOLS 100 Membrane structure 200 Monolith type base material 210 Base material main body 211 Base body 212 First support film 213 Second support film 220 First seal portion 221 First glass seal 222 First primer layer 223 First fluororesin layer 230 Second seal Portion 231 Second glass seal 232 Second primer layer 233 Second fluororesin layer 300 Separation membrane TH1 Through hole

Claims (12)

A porous base body having a first end face, a second end face, and a plurality of through holes penetrating from the first end face to the second end face, respectively;
A fluororesin layer covering the first end surface;
A membrane structure comprising: A primer layer interposed between the base body and the fluororesin layer;
The membrane structure according to claim 1. A separation membrane formed on the inner surface of the plurality of through holes,
The separation membrane generates purified water by filtering and purifying water,
The membrane structure according to claim 1 or 2. The fluororesin layer is composed of PFA.
The film structure according to any one of claims 1 to 3. A fluororesin layer covering the second end face;
The film structure according to any one of claims 1 to 4. A porous base body having a first end face, a second end face, and a plurality of through holes penetrating from the first end face to the second end face, respectively;
A glass seal layer covering the first end surface;
A fluororesin layer covering the glass seal layer;
Comprising
Membrane structure. A primer layer interposed between the fluororesin layer and the glass seal layer;
The membrane structure according to claim 6. A separation membrane formed on the inner surface of the plurality of through holes,
The separation membrane has water permselective properties and dehydrates by pervaporation or vapor permeation.
The membrane structure according to claim 6 or 7. The fluororesin layer is composed of PFA.
The film structure according to any one of claims 6 to 8. A fluororesin layer covering the second end face;
The film structure according to any one of claims 6 to 9. Forming a porous base material body having a plurality of through holes penetrating from the first end surface to the second end surface, and
Forming a fluororesin layer covering the first end surface;
A method for producing a membrane structure comprising: The step of forming the fluororesin layer includes
Forming a fluororesin layer molded body using a fluororesin layer slurry containing fluororesin particles having a particle size of 25 μm or more;
Forming the fluororesin layer by baking the molded body of the fluororesin layer,
The manufacturing method of the film | membrane structure of Claim 11.

Images