JP2014208334A - Method of manufacturing separation membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a separation membrane which can easily respond even when a membrane surface area increases or when viscosity of slurry for deposition for forming a membrane increases.SOLUTION: In a method of manufacturing a separation membrane, a separation membrane is formed by carrying out a drying process of ventilating and drying a part of an end surface of a base material 10 in a covered state with a mask 15 after slurry for deposition for forming the separation membrane is adhered. The process of ventilating and drying in the covered state with the mask 15 may be carried out in a part of the drying process. The mask 15 is continuously or intermittently moved. Other parts can be ventilated intensively by ventilating and drying a part of the end surface of the base material 10 in the covered state with the mask 15.

Description

  The present invention relates to a method for producing a separation membrane, and more particularly to a drying step.

  In recent years, ceramic filters have been used to selectively recover only specific components from a multi-component mixture (mixed fluid). Ceramic filters are superior to organic polymer filters in terms of mechanical strength, durability, corrosion resistance, etc., so they can be used in a wide range of fields such as water treatment, exhaust gas treatment, and pharmaceutical and food fields. It is preferably applied to the removal of suspended substances, bacteria, dust and the like in gas.

  As such a filter, a filter in which a separation membrane such as a carbon membrane, a silica membrane, or a zeolite membrane is formed on a ceramic porous body is known. In order to form the separation membrane on the ceramic porous body, there is a method in which a precursor solution to be a separation membrane is prepared, the precursor solution is deposited on the ceramic porous body, and dried.

  For example, Patent Document 1 describes that a precursor solution is poured into a through-hole of a monolith substrate and air-dried with hot air.

JP 2010-110704 A

  However, in conventional ventilation drying, when the membrane area becomes large or when the viscosity of the slurry for film formation (precursor solution) for forming the membrane becomes high, the size of the ventilation device is increased (of the air outlet portion). Unless the area is increased), the air volume is increased, and the ventilation time is not prolonged, there is a problem that a film thickness distribution occurs and film cracks and peeling occur. However, these measures have a problem of increased installation space and cost.

  An object of the present invention is to provide a method for producing a separation membrane that can be easily handled even when the membrane area is large or the viscosity of a slurry for film formation for forming a membrane is high. .

  The present inventors have found that the above problem can be solved by ventilating and drying in a state where a part of the end face of the substrate is covered with a mask in the drying step. That is, according to the present invention, the following method for producing a separation membrane is provided.

[1] After depositing a film-forming slurry for forming a separation membrane on a monolith-type base material, the film is ventilated in a state where a part of the end surface of the base material is covered with a mask. The manufacturing method of the separation membrane which performs the drying process which dries a slurry and forms the said separation membrane.

[2] A cover region in which a part of the ventilation target region that is the portion to be ventilated of the base material is covered with a mask is provided to perform the ventilation, and the cover region is moved by moving the mask. The method for producing a separation membrane according to [1], wherein the ventilation is further performed.

[3] The method for manufacturing a separation membrane according to [2], wherein the mask is moved continuously or intermittently.

[4] The method for manufacturing a separation membrane according to [2] or [3], wherein an opening area ratio of the opening region not covered with the mask to the area of the ventilation target region is 10 to 50%.

[5] The drying process includes a maskless process in which the ventilation is performed on the entire ventilation target area that is not covered with the mask and is the target of the ventilation, and a part of the ventilation target area is masked. A method for producing a separation membrane according to the above [1], including a step with a mask which provides a cover region covered with a gas and performs the ventilation.

[6] The method for manufacturing a separation membrane according to [5], wherein in the drying step, the step with a mask is performed after the step without the mask is performed.

[7] The method for manufacturing a separation membrane according to [5] or [6], wherein an opening area ratio of the opening area not covered with the mask to the area of the ventilation target area is 15 to 50%.

[8] After attaching a slurry for film formation for forming a separation membrane to a monolith type base material, one of the base materials using a wind tunnel device having a projecting cavity that generates turbulent wind flow The manufacturing method of the separation membrane which forms the said separation membrane by performing the drying process which ventilates from the end surface side of this, and dries the said film-forming slurry.

  By using the mask to reduce the ventilation area and ventilating and drying, it is possible to respond to the increase in the area of the film and the increase in the viscosity of the slurry for film formation without increasing the size of the ventilation apparatus, and a film with reduced cracks can be obtained. It is done.

It is a schematic diagram for demonstrating the drying process by ventilation. It is a schematic diagram which shows the place which made the film-forming slurry adhere in the cell. It is a schematic diagram which shows the mask in which the fan-shaped opening was formed. It is a schematic diagram which shows a semicircular mask. It is a schematic diagram which shows the place which moved the semicircle mask. It is a schematic diagram which shows a maskless process. It is a schematic diagram which shows a circular mask in a process with a mask. It is a schematic diagram which shows the drying process using the wind tunnel apparatus which has a protrusion cavity part, a rectification | straightening trunk | drum, and a reduced flow nozzle part. It is a schematic diagram which shows the drying process using the wind tunnel apparatus of other embodiment which has a protrusion cavity part, a rectification | straightening trunk | drum, and a reduced flow nozzle part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the invention.

(1) Outline As shown in FIG. 1, the separation membrane manufacturing method of the present invention is performed after depositing a film-forming slurry 12 for forming a separation membrane 13 on a monolithic substrate 10 (FIG. 1). 2), the separation membrane 13 is formed by performing a drying process in which a part of the end face of the base material 10 is covered with a mask 15 to dry the slurry 12 for film formation. The step of ventilating and drying in the state covered with the mask 15 may be performed only as part of the drying step. The mask 15 is moved continuously or intermittently. Thus, by ventilating and drying in a state where a part of the end face of the substrate 10 is covered with the mask 15, it is possible to concentrate and ventilate other parts. For this reason, it is possible to easily cope with the case where the membrane area is increased without increasing the size of the ventilator 16 or when the viscosity of the film-forming slurry 12 for forming the membrane is increased.

(2) Separation membrane structure In this specification, what formed the separation membrane 13 in the base material 10 is called the separation membrane structure 1. FIG.

(2-1) Substrate The overall shape and size of the substrate 10 for forming the separation membrane 13 used in the method for producing a separation membrane of the present invention are not particularly limited as long as the separation function is not hindered. Absent. The overall shape includes, for example, shapes such as a columnar shape, a quadrangular prism shape (a cylindrical shape with a cross section orthogonal to the longitudinal direction 7), and a triangular prism shape (a cylindrical shape with a cross section orthogonal to the longitudinal direction 7). It is done. Among these, a columnar shape that is easy to be extruded, has little firing deformation, and is easy to seal with the housing is preferable. When used for microfiltration or ultrafiltration, the diameter (outer diameter) in the cross section perpendicular to the longitudinal direction 7 is preferably 30 to 60 mm and the length in the longitudinal direction 7 is 15 to 2000 mm. In the separation membrane manufacturing method of the present invention, in the drying step, since unevenness in drying in the radial direction can be reduced, even in the case of the large substrate 10 having a diameter (outer diameter) of 60 to 200 mm, A film in which cracks are difficult to occur can be formed.

  As the substrate 10 used in the method for producing a separation membrane of the present invention, a monolith type (monolith shape) as shown in FIG. 1 can be used. The “monolith type” refers to a shape in which a plurality of cells are formed from the first end surface 2a to the second end surface 2b in the longitudinal direction 7 as shown in FIG. Note that the outer shape is not limited to the cylindrical shape as described above.

  The base material 10 of the embodiment shown in FIG. 1 is a cell that is a fluid flow path partitioned by a porous partition wall 3 from one first end surface 2a in the longitudinal direction 7 to the other second end surface 2b. 4 is provided. It is preferable that the base material 10 has 30 to 2500 cells 4 penetrating both ends in the longitudinal direction 7 and parallel to the longitudinal direction 7.

  Examples of the cross-sectional shape of the cell 4 of the substrate 10 (the shape in the cross-section perpendicular to the extending direction of the cell 4) include a circle, an ellipse, a polygon, and the like. A square, a triangle, etc. can be mentioned. The direction in which the cells 4 extend is the same as the longitudinal direction 7 when the substrate 10 is cylindrical.

  When the cross-sectional shape of the cell 4 of the base material 10 is circular, the diameter of the cell 4 is preferably 1 to 5 mm. When the cross section of the cell 4 is not a circle, the cross-sectional area is the diameter of the same circle. By setting the diameter of the cell 4 to 1 mm or more, a sufficient film area can be secured. By making it 5 mm or less, the strength can be made sufficient.

  As a material of the substrate 10, porous ceramic can be used. From the viewpoint of strength and chemical stability, ceramic materials such as alumina, silica, cordierite, mullite, titania, zirconia, and silicon carbide are preferable. The porosity of the substrate 10 is preferably about 25 to 55% from the viewpoint of strength and permeability. Moreover, it is preferable that the average pore diameter of the base material 10 shall be about 0.005-5 micrometers.

(2-2) Separation membrane Although it does not specifically limit as the separation membrane 13 manufactured in the manufacturing method of the separation membrane of this invention, For example, a silica membrane, a carbon membrane, a zeolite membrane, a titania membrane etc. are mentioned. It is done. In the following manufacturing method, a silica film will be described as an example.

(3) Manufacturing Method (3-1) Base Material Next, a manufacturing method of the separation membrane structure 1 using the monolithic base material 10 will be described. First, the raw material of the base material 10 is molded. For example, extrusion is performed using a vacuum extruder. As a result, a monolith-type unfired base material 10 having the cells 4 is obtained. There are other methods such as press molding and cast molding, which can be selected as appropriate. Next, the unfired base material 10 is fired at 900 to 1450 ° C., for example.

  It is preferable to provide glass seals on both end faces of the base material 10 in the longitudinal direction 7 before the attaching step. The glass seal prevents the fluid to be processed from flowing in or out through the region where the separation membrane 13 is not formed when the separation membrane 13 is used.

(3-2) Film Forming Slurry Next, a film forming slurry 12 is prepared. For example, in the case of a silica membrane, a silica sol liquid can be used as the film-forming slurry 12 to be attached to the substrate 10 and dried to form the separation membrane 13. The silica sol solution is prepared by hydrolyzing tetraethoxysilane in the presence of nitric acid at 50 ° C. for 5 hours to obtain a sol solution, which is diluted with ethanol and adjusted to 1.0% by mass in terms of silica. It is preferable to do. The ethanol concentration of the silica sol solution after dilution with ethanol is preferably 96% by mass. Although it is possible to dilute with water instead of diluting with ethanol, diluting with ethanol allows a thinner film to be formed in a single film formation, and a film with a high transmission rate can be obtained.

(3-3) Adhering Step Next, the film-forming slurry 12 (for example, silica sol liquid) is attached in the cell 4 of the monolithic substrate 10. Although it does not specifically limit as a method of making the film-forming slurry 12 adhere in the cell 4 of the base material 10, For example, the following method is mentioned.

  The base material 10 is fixed to the lower end of the wide-mouth funnel, the film-forming slurry 12 is supplied to the wide-mouth funnel, the film-forming slurry 12 is poured into the cell 4 from the upper part of the base material 10, and is passed through the cell 4 to form the film. Slurry 12 can be deposited.

  Alternatively, a dip film forming method is used in which the film forming slurry 12 is fed into each cell 4 from one open end of each cell 4 at a rate of about 0.3 to 300 cm / min using a liquid feed pump. You can also.

  FIG. 2 shows a state in which the film-forming slurry 12 is attached in the cell 4 by the attaching process. The film-forming slurry 12 becomes the separation membrane 13 through a subsequent drying step and heat treatment step.

(3-4) Drying Step Next, the film-forming slurry 12 attached to the base material 10 is dried. FIG. 1 is a schematic diagram illustrating an embodiment of a drying process. The ventilation device 16 is arranged on one end surface 2 (first end surface 2a) side of the base material 10, and air is sent from the ventilation device 16 into the cell 4 of the base material 10, and the other end surface 2 ( It exhausts from the 2nd end surface 2b side. Ventilation may be performed from the bottom to the top of the substrate 10 or from the top to the bottom. In this manner, the film formed by the film-forming slurry 12 is ventilated and dried while passing air through the cell 4. By passing air through the cell 4 of the substrate 10 in this manner, the entire film formed by the film-forming slurry 12 such as a silica film formed on the surface of the cell 4 is dried by wind. In the present invention, when a desired film thickness cannot be obtained by one film formation and drying, the film formation and drying steps may be repeated a plurality of times until the desired film thickness is obtained.

  In the case of a silica film, the temperature of the wind sent from the ventilation device 16 is preferably 10 to 80 ° C. By passing a wind of 10 ° C. or higher, drying can proceed and a dense film can be obtained. Moreover, a crack is hard to generate | occur | produce on the film surface by setting it as 80 degrees C or less. The speed at which the wind for drying passes through the cell 4 is preferably 0.1 to 100 m / sec, and more preferably 5 to 30 m / sec. It is easy to dry by setting the speed at which the wind passes through the cell 4 to 0.1 m / second or more. Moreover, cracks are unlikely to occur when the speed at which the wind passes through the cell 4 is 100 m / second or less.

  In the separation membrane manufacturing method of the present invention, in the drying step, a part of the end surface 2 of the substrate 10 is covered with the mask 15 and then dried by ventilation. Hereinafter, a method using the mask 15 will be described.

(3-4-1) First Method The first method in the drying step of the method for producing a separation membrane of the present invention is to mask a part of the ventilation target area, which is a part to be ventilated, of the base material 10 with a mask 15. The cover area covered with is provided to ventilate, and the mask 15 is moved to move the cover area and further ventilate. The mask 15 may cover the end surface 2 on the wind inlet side of the substrate 10 or the end surface 2 on the outlet side. Even if the end surface 2 on the outlet side is covered, the flow of the wind is blocked, so that the same effect as covering the end surface 2 on the inlet side can be obtained.

  In FIG. 1, a mask 15 having a fan-shaped opening is used. The mask 15 is provided so as to cover the first end surface 2a on the wind inlet side. The figure seen from the ventilation apparatus 16 side in FIG. 3 is shown. The mask 15 covers the end surface 2 of the substrate 10 at a portion other than the fan-shaped opening area. The mask 15 is arranged so that the central axis of the mask 15 and the central axis of the substrate 10 coincide. Then, the cover area is moved by moving the mask 15 continuously or intermittently. Specifically, the mask 15 is rotated clockwise or counterclockwise around the central axis. The rotation may be performed continuously or intermittently.

  Another embodiment of the first method will be described with reference to FIGS. 4A and 4B. In FIG. 4A, the mask 15 is semicircular. The left side is covered with a mask 15, and the end surface 2 of the substrate 10 is visible on the right side. Ventilation is performed in this state, and after a certain time, the mask 15 is inverted as shown in FIG. 4B. Note that the mask 15 may be rotated as described with reference to FIG.

  It is preferable that the ratio of the opening area of the opening area not covered with the mask to the area of the ventilation target area is 10 to 50%. By setting it as such a range, since the wind from the ventilation apparatus 16 can be sent intensively to a specific area | region, even if it does not enlarge the ventilation apparatus 16, a film | membrane can be dried efficiently.

  The ventilation time from the opening of the mask 15 to a certain region is preferably 5 to 80 seconds, and more preferably 10 to 60 seconds. By setting it to 5 seconds or more, it is possible to prevent the excess slurry from being blown off to increase the film thickness and to prevent generation of cracks. In addition, it is possible to prevent cracks from occurring due to rapid film shrinkage during firing due to insufficient drying. By setting it to 80 seconds or less, it is possible to prevent the surplus slurry in the mask 15 portion from being naturally dried to increase the thickness and prevent cracks from occurring.

(3-4-2) Second Method The second method in the drying step of the separation membrane manufacturing method of the present invention is a portion in which the drying step is not covered with the mask 15 and is a target of ventilation of the base material 10. This is a method including a maskless process for ventilating all of the ventilation target areas and a masked process for ventilating by providing a cover area in which a part of the ventilation target area is covered with the mask 15. Also in the second method, the mask 15 may cover the end surface 2 on the inlet side of the substrate 10 or may cover the end surface 2 on the outlet side.

  In this case, it is preferable to perform the masked process after performing the maskless process. The second method will be described with reference to FIGS. 5A and 5B. FIG. 5A shows a maskless process. Ventilation is performed over the entire region of the end surface 2 of the substrate 10. After a certain period of time, as shown in FIG. 5B, a cover area is provided in which a part of the ventilation target area is covered with a mask 15. At this time, the cover region preferably covers the central portion of the end surface 2. When ventilation is performed by the ventilation device 16, normally, a large amount of wind flows in the central portion, and the wind is weak in the outer peripheral portion. Therefore, a difference is likely to occur between the central portion and the outer peripheral portion in drying the film. By providing the cover region in the center part in the process with cover, the difference in drying of the film between the center part and the outer peripheral part can be reduced. Thereby, a uniform film can be manufactured.

  Note that the process with a mask and the process without a mask may be repeated, or the process with a mask may be performed after the process without a mask. This is preferable because it can be blown off to some extent.

  It is preferable that the ratio of the opening area of the opening area not covered with the mask 15 to the area of the ventilation target area is 15 to 50%. By setting it as such a range, since the wind from the ventilation apparatus 16 can be sent intensively to a specific area | region, even if it does not enlarge the ventilation apparatus 16, a film | membrane can be dried efficiently.

(3-4-3) Third Method The third method in the drying step of the method for producing a separation membrane of the present invention includes a projecting cavity portion 22 that generates wind turbulence and a rectifying cylinder that attenuates wind turbulence. This is a method of blowing air to the substrate 10 using the wind tunnel device 21 having the portion 23 and the contracted nozzle portion 24. That is, a drying process is performed in which the film forming slurry 12 is dried by blowing air from one end face 2 side of the substrate 10 using the wind tunnel device 21 having the projecting cavity portion 22, the rectifying body portion 23, and the contracted nozzle portion 24. Thus, the separation membrane 13 is formed. The projecting cavity portion 22 is for generating a turbulent wind flow, and is a cavity portion that projects in a direction different from the wind flow direction 25. The rectifying body portion 23 attenuates the turbulence of the wind, and the contracted nozzle portion 24 is a portion that further attenuates the turbulence of the wind. 6A and 6B show a drying process using the wind tunnel device 21 having the protruding cavity portion 22, the rectifying body portion 23, and the reduced flow nozzle portion 24. The wind tunnel device 21 of FIG. 6A is formed by bending a wind outflow direction 27 perpendicular to the inflow direction 26. A projecting cavity portion 22 projecting in the inflow direction 26 is provided, and the wind tunnel device 21 is formed in a T shape. In FIG. 6B, the protruding cavity 22 part is formed as a diameter-enlarged part 22a in which the diameter of the flow path is increased. In other words, the protruding cavity 22 is formed so as to protrude in a direction different from the flow direction of the wind.

  The projecting cavity portion 22 is a space serving as a buffer, and the rectifying body portion 23 and the contracted-flow nozzle portion 24 are spaces for removing the turbulence of the wind, and these spaces remove the non-uniformity of the wind flow and attenuate the turbulence. It is preferable. In the embodiment of FIG. 6A, the effect of removing wind non-uniformity can be further obtained by changing (bending) the flow direction 25 of the wind. The effect is further enhanced by the formation of the protruding cavity 22 at the portion where the wind flow direction 25 changes. Examples of the shape of the protruding cavity 22 include a spherical shape, a cylindrical shape, and a quadrangular prism shape. It is more preferable to insert a plurality of rectifying networks of about 20 mesh (the number of eyes per inch is 20) into the rectifying body 23. Further, in order to make the wind velocity distribution uniform and reduce the turbulence, the restriction ratio (ratio of the diameter 28 of the rectifying cylinder portion and the diameter 29 of the outlet which is the rectifying space (the diameter 28 of the rectifying cylinder / the diameter of the outlet) The diameter 29)) is preferably about 5 to 20. FIG. 6B shows an embodiment in which the aperture ratio is 5 or more.

  The third method can be performed in combination with the first method or the second method, or can be performed alone. When the third method is used in combination with the first method or the second method, a mask 15 is provided on the wind outlet side of the separation membrane structure 1 as shown in FIGS. 6A and 6B. By providing the mask 15 on the outlet side, the same effect as that provided on the inlet side can be obtained.

(3-5) Heat treatment step After film formation and drying as described above, the temperature is raised at 100 ° C./hr, held at 500 ° C. for 1 hour, and then lowered at 100 ° C./hr. The adhesion process, the drying process, and the heat treatment process of the film forming slurry 12 (for example, silica sol solution) can be repeated 3 to 5 times to obtain the separation membrane 13 (silica membrane).

  The film thickness of the separation membrane 13 finally obtained is preferably 0.1 to 10 μm, and more preferably 0.1 to 3 μm. By setting this range, sufficient selectivity can be obtained and the permeation flow rate can be increased.

  The use of the separation membrane 13 manufactured according to the embodiment of the present invention is not particularly limited, but can be suitably used as a filter for separating a mixed liquid or the like.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

(Base material)
As the monolithic substrate 10, a porous substrate 10 made of alumina having a diameter (outer diameter) of 180 mm and a length in the longitudinal direction 7 of 1000 mm as shown in FIG. 1 was used. Further, the substrate 10 had 2000 cells 4 penetrating to both end sides in the longitudinal direction 7 and parallel to the longitudinal direction 7. The inner diameter of the cell 4 was 2.0 mm.

  A glass seal material was applied to both end faces (first end face 2a, second end face 2b) of the substrate 10, and the glass seal material was heated at 650 ° C. to form a glass seal.

(Slurry for film formation)
Tetraethoxysilane is hydrolyzed in the presence of nitric acid at 50 ° C. for 5 hours to form a sol solution, which is diluted with ethanol or water and adjusted to 1.0% by mass in terms of silica. Thus, a silica sol solution (film forming slurry 12) was produced.

(Adhesion process)
The base material 10 was installed so that the longitudinal direction 7 of the cell 4 was the vertical direction, the first end surface 2a was upward, and the second end surface 2b was downward. About 8000 ml of ceramic sol, the temperature of which was controlled at 3 to 23 ° C., was poured into the cell 4 from the upper part of the substrate 10 and allowed to pass through. Ventilation was performed from the upper part of the substrate 10 for about 5 seconds to remove excess sol solution. In addition, it confirmed that it formed into a film on the whole inner wall of the cell 4 by this film-forming process, as shown in FIG.

(Drying process)
After the attaching step, as shown in FIG. 1, the ventilation device 16 was disposed on the first end face 2a side of the substrate 10 on which the silica film was formed, and 45 ° C. air was sent to dry the silica film. This will be described in detail below.

(Examples 1 to 16, Comparative Example 1)
About Examples 1-16, the above-mentioned 1st method was used. That is, the cover area covered with the mask 15 was provided to ventilate, and the cover area was moved by moving the mask 15. A mask 15 as shown in FIGS. 3, 4A, and 4B was used. Table 1 shows the position where the mask 15 is provided, the opening area ratio of the mask 15 and the central angle 15a (angle of the opening). In Examples 1 to 12, 14, and 15, the mask 15 was continuously rotated. In Example 13, the mask 15 was inverted intermittently. “Ventilation time to a certain area” in Table 1 is a time during which ventilation is performed in a certain ventilation target area that is a target of ventilation. For example, in Example 2, the mask 15 provided with an opening having a central angle of 90 ° was used, and air was passed through a ventilation target region having a central angle of 90 ° for 30 seconds. Since the mask 15 was rotated and the remaining 270 ° region was similarly dried, the total drying time was 30 seconds × (360/90) = 120 seconds. Comparative Examples 1 to 4 are examples in which the mask 15 was not used (opening area ratio 100%, center angle 360 °). “Ventilation time to a certain area” in Table 1 of Comparative Examples 1 to 4 is the total ventilation time required for drying without using a mask.

(Heat treatment process)
Next, the sample was heated at 100 ° C./h in an electric furnace, held at 500 ° C. for 1 hour, and then cooled at 100 ° C./h for heat treatment. The deposition process of the film-forming slurry 12 (silica sol solution), the drying process, and the heat treatment process were repeated four times to obtain samples of Examples and Comparative Examples.

(Evaluation)
In order to investigate the amount of defects in the separation membrane 13, the degree of vacuum of the cell 4 was measured. One of the cells 4 is a vacuum pump (manufactured by ULVAC KIKOH Co., Ltd .: direct-coupled oil rotary vacuum pump, model number: G-20DA, exhaust speed 24 L / min, ultimate pressure 1.3 × 10 ⁻¹ Pa, two-stage type) A vacuum gauge (manufactured by GE Sensing: calibrator, model number: DPI800) was connected to the other cell 4 to evacuate the inside of the cell 4, and the ultimate vacuum in the cell 4 was measured.

  A sample having a better degree of vacuum than Comparative Example 1 without a mask was evaluated as ◯ (good). Furthermore, those having a particularly good vacuum degree of −85 kPa or less were evaluated as ◎ (excellent), but those having a long ventilation time and a high wind speed even though the degree of vacuum is good are not preferable in the manufacturing process. No).

  As shown in Table 1, particularly good results were obtained when the opening area ratio was 12.5 to 50%. The ventilation time to a certain area was 30 seconds better than 10 seconds or 60 seconds. The wind speed was better at 10 m / sec than at 5 m / sec or 30 m / sec. The method of moving the mask 15 was not different between the continuous method (Example 4) and the inversion method (Example 13). When the mask 15 was provided on the outlet side, the same result as that obtained when the mask 15 was provided on the inlet side was obtained.

  Comparative Examples 1 to 4 were dried without using a mask, but Comparative Examples 1 and 2 had poor vacuum. In Comparative Examples 3 and 4, the degree of vacuum could be improved, but in Comparative Example 3, the total ventilation time was long, and in Comparative Example 4, the wind speed had to be increased to 40 m / second.

(Examples 17 to 30, Comparative Example 5)
About Examples 17-30, after producing the base material 10 like Example 1 etc., the slurry 12 for film-forming was made to adhere to the base material 10, and the drying process by the above-mentioned 2nd method was performed. That is, as shown in FIGS. 5A and 5B, the maskless process was performed for 30 seconds, and then the masked process was performed. Table 2 shows the position where the mask 15 is provided, the ratio of the opening area of the mask 15 and the time of the process with the mask. Comparative Example 5 is an example in which the mask 15 was not used (Comparative Example 5 is the same as Comparative Example 1 in Table 1 and has a maskless process of 30 seconds and a masked process of 0 seconds).

  Heat treatment was performed in the same manner as in Example 1 to obtain a silica film, and the silica film was evaluated. A sample having a better degree of vacuum than Comparative Example 5 without a mask was evaluated as ◯ (good). Furthermore, those having a particularly good vacuum degree of −85 kPa or less were evaluated as ◎ (excellent).

  As shown in Table 2, particularly good results were obtained when the opening area ratio was 16 to 49%. The wind speed was better at 10 m / sec than at 5 m / sec or 30 m / sec. When the mask 15 was provided on the outlet side, the same result as that obtained when the mask 15 was provided on the inlet side was obtained.

  The method for producing a separation membrane of the present invention can be used as a method for producing a separation membrane with few defects for separating a mixed fluid.

1: separation membrane structure, 2, 2a, 2b: end face, 3: partition, 4: cell, 7: longitudinal direction, 10: substrate, 12: slurry for film formation, 13: separation membrane, 15: mask, 15a : Center angle (of the opening), 16: Ventilation device, 21: Wind tunnel device, 22: Projection cavity, 22a: Expanded diameter portion, 23: Rectification body portion, 24: Reduced flow nozzle portion, 25: Wind flow direction , 26: inflow direction, 27: outflow direction, 28: diameter of the rectifying body, 29: diameter of the outlet.

Claims (8)

After depositing a slurry for forming a separation membrane on a monolithic substrate,
A method for producing a separation membrane, wherein the separation membrane is formed by performing a drying process in which a part of the end face of the base material is covered with a mask to ventilate and dry the film-forming slurry.   A cover region in which a part of the ventilation target region that is the target of ventilation of the base material is covered with a mask is provided to perform the ventilation, and the cover region is moved by moving the mask to further move the cover. The manufacturing method of the separation membrane of Claim 1 which ventilates.   The method for manufacturing a separation membrane according to claim 2, wherein the mask is moved continuously or intermittently.   The method for manufacturing a separation membrane according to claim 2 or 3, wherein an opening area ratio of an opening region not covered with the mask to an area of the ventilation target region is 10 to 50%.   In the drying step, a maskless step of performing the ventilation on all ventilation target regions that are portions to be ventilated of the base material that are not covered with the mask, and a part of the ventilation target region is covered with a mask. A method for producing a separation membrane according to claim 1, further comprising a step with a mask that provides a cover region and performs the ventilation.   The method for manufacturing a separation membrane according to claim 5, wherein in the drying step, the step with the mask is performed after the step without the mask is performed.   The method for manufacturing a separation membrane according to claim 5 or 6, wherein an opening area ratio of the opening area not covered with the mask to the area of the ventilation target area is 15 to 50%. After depositing a slurry for forming a separation membrane on a monolithic substrate,
Separation membrane for forming the separation membrane by performing a drying step of drying the slurry for film formation by blowing air from one end face side of the substrate using a wind tunnel device having a projecting cavity that generates turbulent flow of wind Manufacturing method.

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