JP6636932B2 - Membrane structure and manufacturing method thereof - Google Patents

Description

  The present invention relates to a film structure and a method for manufacturing the same.

  BACKGROUND ART Conventionally, a membrane structure including a substrate body having a plurality of through holes, a separation membrane formed on an inner surface of the through hole, and a glass seal covering an end surface of the substrate body has been known. The glass seal is provided to prevent the mixed solution to be filtered from entering the base material 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, when 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 to suppress the intrusion of the mixed solution even if a crack occurs in the glass seal. Further, since cracks and peeling may occur in the glass seal, there is also a demand for suppressing the intrusion of the mixed solution without providing the glass seal.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a membrane structure capable of suppressing intrusion of a mixed solution into a substrate body.

  The film structure according to the present invention includes a porous base material main body and a fluororesin layer. The substrate body has 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. The fluororesin layer covers the first end face.

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

Perspective view of the membrane structure Partial enlarged view of AA section of FIG. Partial enlarged view of AA 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 ratios of dimensions may be different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. In addition, it is needless to say that dimensional relationships and ratios are different between drawings.

  In the following embodiments, “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 the film structure 100)
FIG. 1 is a perspective view of the film structure 100. FIG. 2 is a partially enlarged view of an AA cross section in 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 220, and a second seal 230.

  The base body 210 is a porous body. The base body 210 is formed in a columnar 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 face S1 is provided opposite to the second end face 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 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 may be 1 to 5 mm.

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

The base 211 is formed in a columnar shape. A plurality of through holes TH2 are formed in the base 211. The base 211 is made of a porous material. As the porous material of the base 211, ceramics, metal, resin, and the like can be used, and a porous ceramic material is particularly preferable. Aggregate particles of a porous ceramic material include alumina (Al ₂ O ₃ ), titania (TiO ₂ ), mullite (Al ₂ O ₃ .SiO ₂ ), selven, and cordierite (Mg ₂ Al ₄ Si ₅ O ₁₈ ). Alumina is particularly preferable in consideration of availability, clay stability and corrosion resistance. The base 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 size of the porous material forming the base 211 can be 5 μm to 100 μm. The average pore diameter of the substrate 211 can be measured by a mercury porosimeter. In the present embodiment, the “average particle size” is a value obtained by arithmetically averaging the maximum diameters of 30 measurement target particles measured by cross-sectional microstructure observation using a scanning electron microscope (SEM).

  The first support film 212 is formed on the inner surface of the base 211 (through hole TH2). The first support film 212 is formed in a cylindrical shape. The first support film 212 is made of the same porous ceramic material as the base body 211. The thickness of the first support film 212 in a direction perpendicular to the central axis of the through hole TH1 (hereinafter, referred to as a 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 base 211, and may 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 the same porous ceramic material as the base 211. The thickness of the second support film 213 in the radial direction can be set to 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 part 220 has 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 of the base body 210 and a part of the side surface S3. The first glass seal 221 suppresses a mixed fluid (for example, an organic solvent or the like) to be filtered, which flows into a 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 forming the first glass seal 221, glass that does not allow a mixed fluid to pass therethrough can be used, and alkali-free glass that can suppress diffusion of an alkali component is particularly preferable. The thickness of the first glass seal 221 in a direction perpendicular to the first end surface S1 (that is, the longitudinal direction) can be set to 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 adhesive strength 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 the fluororesin include PTFE (Poly Tetra Fluoro Ethylene; ethylene tetrafluoride), PFA (Tetra Fluoro Ethylene-Perfluoro Alkyl vinyl Ether Copolymer), and FEP (Fluorinated Ethylene Propylene Copolymer; At least one of ethylene tetrafluoride / propylene hexafluoride) or a copolymer containing these basic structures can be used. As the adhesive component, a commercially available Teflon primer can be used. The thickness of the first primer layer 222 in a 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 interposed 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 face 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 the basic structure thereof can be used. PFA is suitable as a sealing material because it has higher chemical corrosion resistance than FEP. Since PTFE has a lower melting point than PFA and can be applied at a low temperature, PTFE is particularly suitable as a sealing material. The thickness of the first fluororesin layer 223 in a direction perpendicular to the first end surface S1 can be 1 μm to 2000 μm, and is preferably 100 μm or more.

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

  The second glass seal 231 covers the entire surface of the second end surface S2 and a part of the side surface S3 of the base body 210. 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 a direction perpendicular to the second end face S2 (that is, in the longitudinal direction) can be set to 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 adhesive strength 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 adhesion between the second primer layer 232 and the second fluororesin layer 233 is larger than the adhesion 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 a 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 second end face S2 and a part of the side face S3 with the second glass seal 231 and the first primer layer 22 interposed 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 face 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 a direction perpendicular to the second end surface S2 can be set to 10 μm to 2000 μm, and is preferably 100 μm or more.

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

(Method of Manufacturing Film Structure 100)
First, a formed body of the base 211 having a plurality of through holes TH2 is formed using a clay containing a porous material. As a method of forming a molded body of the base 211, an extrusion molding method using a vacuum extrusion molding machine, a press molding method, or a casting molding method can be used.

  Next, the formed body of the base 211 is fired (for example, at 500 ° C. to 1500 ° C. for 0.5 to 80 hours) to form the base 211.

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

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

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

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

  Next, using the slurry for the second support film, a formed body of the second support film 213 is formed 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 sucking the second support film slurry from the side surface S3 of the base 211 with a pump while supplying the slurry to the inside of the first support film 212. Deposit the body.

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

  Next, a glass sealing slurry is prepared by mixing glass frit, water, an organic binder, and the like.

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

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

  Next, the separation film 300 is formed on the inner surfaces of the plurality of through holes TH1. As a method for forming the separation film 300, an appropriate method depending on the type of the separation film 300 may be used. For example, when forming a DDR type zeolite membrane as the separation membrane 300, a seeding step by a flow-down method, a hydrothermal synthesis step of the 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 product 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 to 380 ° C. for 0.1 to 2 hours). Thus, 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. In the case where the first and second fluororesin layers 223 and 233 are formed by PFA coating or PFA powder coating, the fluororesin base material is formed by using at least a part of coarse fluororesin particles having a particle size of 25 μm or more. Film defects due to permeation into the main body 210 can be suppressed.

(Other embodiments)
As described above, one embodiment of the present invention has been described, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention.

  (A) In the above embodiment, the monolithic base material 200 has the base material body 210, the first seal part 220, and the second seal part 230, but the first seal part 220 and the second seal part 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, but may not have the first primer layer 222, as shown in FIG. Similarly, the second seal 230 may not have the second primer layer 232.

  (C) In the above embodiment, the first seal portion 220 has the first glass seal 221, but may not have the first glass seal 221 as shown in FIG. 3. Similarly, the second seal portion 230 may not have the second glass seal 231. As described above, when each seal portion does not have a glass seal, the separation membrane 300 can be suitably used as a water purification membrane that generates purified water by filtering and purifying 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 have the same structure. It is not necessary to have at least one. When the base body 210 does not have the second support film 213, the separation membrane 300 is formed on the first support film 212. Further, 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 base 211.

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

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

  (G) In the above embodiment, the membrane structure 100 includes the monolith-type substrate 200 and the separation membrane 300, but does not have to 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 separation membranes for solid-liquid separation by a microfiltration operation for water purification.

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

(Production of Sample Nos. 1 to 3)
First, 20 parts by mass of a frit as a sintering aid are added to 100 parts by mass of alumina particles having an average particle size of 50 μm as aggregate particles, and then water, a dispersant and a thickener are added and kneaded. A clay was obtained.

  Next, the formed body was dried and fired (1250 ° C., 1 hour, heating and cooling rate 100 ° C./hour) to produce a substrate. The dimensions of the substrate were 30 mm in diameter × 30 mm in length. 55 through holes were formed in the substrate.

  Next, 14 parts by mass of a frit as a sintering aid are added to 100 parts by mass of alumina particles having an average particle size 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 film was prepared. Next, a formed 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 slurry for the first support film. Next, the first support film was formed by firing the formed body of the first support film in an electric furnace (at 950 ° C. for 1 hour in an air atmosphere, and at a temperature increase / decrease rate of 100 ° C./hour).

  Next, water, a dispersant, 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 slurry for the second support film. Next, a formed body of the second support film was formed on the inner peripheral surface of the first support film by a filtration method using the slurry for the second support film. Next, the second support film was formed by firing the formed body of the second support film in an electric furnace (at 950 ° C. for 1 hour in an air atmosphere, at a rate of temperature increase and decrease of 100 ° C./hour). As described above, a base body having a plurality of through holes was completed.

  Next, a glass sealing slurry was prepared by mixing glass frit, water and an organic binder. Next, a glass seal slurry was applied to both end surfaces of the base material body to form a set of glass seal compacts. Next, a set of molded glass seals was fired in an electric furnace (at 950 ° C. for 1 hour in an air atmosphere, at a rate of temperature increase and decrease of 100 ° C./hour) to form a set of glass seals.

  Next, the sample no. In 3, a mixture of a fluororesin and an adhesive component was applied to the surface of a set of glass seals and dried to form a set of molded products of a primer layer. On the other hand, the sample No. In the cases of Nos. 1 and 2, a molded product of one set of primer layers was not formed.

  Next, the sample no. In 2, a pair of fluororesin layers (50 μm thick) were formed by applying and baking PFA on the surface of each of the pair of glass seals. Similarly, for sample no. In No. 3, PFA was applied to the surface of each of the pair of primer layers and baked to form a pair of fluororesin layers (thickness: 50 μm). On the other hand, the sample No. In No. 1, the fluororesin layer was not formed. Thus, the sample No. The seal portion of Sample No. 1 is constituted only by a glass seal, The seal portion of Sample No. 2 is composed of a glass seal and a fluororesin layer. The seal portion 3 is composed of a glass seal, a primer layer and a fluororesin layer.

  As described above, the sample No. 1 to No. 3 was completed.

(Evaluation of durability of seal part)
First, sample no. 1 to No. The membrane structure of No. 3 was immersed in an acetic acid aqueous solution (water concentration: 50%) in a pressure vessel and sealed.

  Next, the pressure vessel was heated to 200 ° C., taken out every 80 hours, 200 hours, 600 hours, 1000 hours, 1200 hours, and 1600 hours, and checked for cracks in the glass seal and peeling of the fluororesin layer. Observed. The presence or absence of cracks was determined based on whether or not the dye applied to the surface of the seal portion permeated the cracks. When the dye penetrates into the crack, it is expected that the treatment liquid will seep out and leak even during dehydration separation. The observation results are shown 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, cracks in the glass seal and peeling of the fluororesin layer were not observed after 80 hours. On the other hand, in Sample No. In No. 1, cracks in the glass seal were observed after 80 hours. Therefore, it was confirmed that cracking of the glass seal can be suppressed by protecting the glass seal with the fluororesin layer.

  In addition, in Sample No. in which a glass seal and a fluororesin layer were bonded with a primer layer. In No. 3, peeling of the fluororesin layer was not observed even after 1000 hours or more. Therefore, it was confirmed that peeling of the fluororesin layer could be suppressed by bonding 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. Sample Nos. 1 to 3 in the same process as in Nos. 1 to 3. Film structures according to Nos. 4 and 5 were produced. However, the sample No. In Examples 4 and 5, the size of the substrate is set to 30 mm in diameter × 160 mm in length, a DDR type zeolite film is formed on the inner surface of the second support film, and then PFA is applied and baked on a glass seal to obtain a fluororesin. A layer (thickness: 50 μm) was formed.

  (Evaluation of influence of fluororesin layer on separation performance)

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

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

  Furthermore, each sample after measuring the initial performance was sealed in a pressure-resistant container together with a small amount of water, and heated at 170 ° C. for 200 hours, thereby exposing each sample to water vapor to deteriorate the sample. After being exposed to water vapor, each sample was taken out and dried, and while the mixed fluid shown in Table 2 was supplied 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 rate was calculated from the amount of liquid permeating each sample, and the separation coefficient α was calculated based on the above equation (1).

  As shown in Table 2, the sample No. The transmission speed and the separation coefficient α of Sample No. 5 where no fluororesin layer was provided were obtained. It was equivalent to 4. This confirmed that the presence or absence of the fluororesin layer did not affect the initial separation performance. In addition, when the performance after the deterioration is compared, the sample No. 5 was confirmed to have little deterioration.

  In addition, the sample No. In No. 5, the permeation rate and the separation coefficient α could be maintained 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.

(Ease of production of fluororesin layer)
First, a slurry for a fluororesin layer was prepared using the materials shown in Table 3. As shown in Table 3, sample no. Sample No. 6 used fluororesin particles having a particle size of 5 μm. Sample No. 7 used fluororesin particles having a particle size of 25 μm. In Nos. 8 to 11, fluororesin particles having a particle size of 5 μm and a particle size 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 based on the number of pinholes in which the dye applied to the surface of the seal portion was soaked. Table 3 shows the results of determining the number of defects.

  As shown in Table 3, when the fluororesin layer is directly applied to the porous base material body and baked, the sample No. using fluororesin particles having a particle diameter of 25 μm larger than the pore diameter of the base material body was used. In Nos. 7 to 11, defects in the fluororesin layer could be suppressed. This is because the permeation of the fluororesin particles into the base body could be suppressed.

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

  Next, chemical water washing is generally performed with acid-alkali in tap water use, and a chemical resistance cycle test was performed to evaluate the chemical resistance of each sample to acid-alkali. In the chemical solution resistance cycle test, a step of immersing the seal part of each sample in sulfuric acid (PH1.8) in an autoclave and heating (150 ° C., 50 hours), a step of washing and drying the seal part, The step of immersing the seal portion in NaOH (2% aqueous solution) in an autoclave and heating (150 ° C., 50 hours) was defined as one cycle. Sample No. In Sample No. 12, one cycle of the chemical resistance cycle test was performed. In 13 and 14, the chemical solution 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 the fluororesin layer In Nos. 13 and 14, peeling did not occur in the seal portion even after two cycles of the chemical resistance cycle test. On the other hand, in Sample No. In 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.

100 Membrane Structure 200 Monolithic Base 210 Base Main Body 211 Base 212 First Support Film 213 Second Support Film 220 First Seal 221 First Glass Seal 222 First Primer Layer 223 First Fluororesin Layer 230 Second Seal Part 231 second glass seal 232 second primer layer 233 second fluororesin layer 300 separation membrane TH1 through hole

Claims (5)

A porous base body having a first end face, a second end face, and a plurality of through holes each penetrating from the first end face to the second end face;
A first fluororesin layer covering the first end face;
Equipped with a,
The thickness of the first fluororesin layer is 10 μm or more and 2000 μm or less,
The first fluororesin layer includes fluororesin particles having a diameter larger than the pore diameter of the base body,
Membrane structure. Comprising 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. The first fluororesin layer is composed of PFA,
Film structure according to claim 1 or 2. A second fluororesin layer covering the second end face ;
The thickness of the second fluororesin layer is 10 μm or more and 2000 μm or less,
The second fluororesin layer includes fluororesin particles having a diameter larger than the pore diameter of the base body,
Film structure according to any one of claims 1 to 3. Forming a porous base body having a plurality of through holes penetrating from the first end face to the second end face, respectively;
Forming a fluororesin layer covering the first end face;
Equipped with a,
The step of forming the fluororesin layer,
A step of forming a molded article of a fluororesin layer using a fluororesin layer slurry containing fluororesin particles having a particle diameter larger than the pore diameter of the base body,
Forming the fluororesin layer by baking the molded body of the fluororesin layer,
Including
The thickness of the fluororesin layer is 10 μm or more and 2000 μm or less,
A method for manufacturing a membrane structure.

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