JP2007289938A - Method and apparatus for manufacturing microporous membrane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing a microporous membrane which can manufacture a microporous membrane of a desired pore size by preventing the pore size from varying in a solidification process or washing process. <P>SOLUTION: The manufacturing apparatus 10 for the microporous membrane 44 has a rinse tank 48 for washing the microporous membrane 44 by transferring the microporous membrane 44 in a liquid, the inside of the rinse tank 48 installs a turn bar 50 having a plurality of jetting openings 86A... on its surface, and the jetting openings 86A... of this turn bar 50 jet rinse water, thereby transferring the microporous membrane 44 with non-contact. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and apparatus for producing a microporous membrane, and more particularly to a method and apparatus for producing a polysulfone-based microporous membrane used in fields such as pharmaceutical industry, food industry, electronics industry, and nuclear industry.

  In fields such as the pharmaceutical industry and the food industry, microporous membranes are used to remove fine particles and bacteria of about 0.1 to 5 μm. This microporous membrane is generally produced using cellulose ester, aliphatic polyamide, polyfluorocarbon, polysulfone, polypropylene or the like as a raw material.

  Microporous membranes include symmetric membranes in which the pore diameter is uniform in the film thickness direction, and asymmetric membranes in which the pore diameter varies in the film thickness direction. Patent Document 1 describes a method for producing a microporous membrane having a minimum pore size layer inside the membrane. This microporous membrane has a smaller pore resistance on the surface of the membrane than the internal pore size, and thus has a low filtration resistance and a high efficiency of capturing fine particles and bacteria. Further, the microporous membrane of Patent Document 1 does not deteriorate the filtration performance even if the surface is lost, and can always maintain a high filtration performance. Such a microporous membrane is used by being incorporated in a cartridge, for example (see Patent Document 2).

In the production of a microporous film, as described in Patent Document 1, a dope for forming a microporous film is first cast on a support to form a liquid film of dope on the support. . Next, the liquid film on the support is brought into contact with humidity control air. As a result, the liquid film on the support undergoes coacervation from the surface toward the inside, and a fine coacervation phase is formed from the surface of the liquid film to the inside. By further transporting this liquid film through the liquid of the coagulating liquid in the coagulating tank, the solvent of the liquid film is dissolved and replaced with the coagulating liquid, and the solvent replacement is performed. As a result, the aforementioned coacervation phase is fixed as fine pores, and at the same time, pores other than the fine pores are formed by phase separation of the liquid membrane, and a microporous membrane is formed. The microporous membrane thus formed is peeled off from the support and then cleaned by being transported in the liquid inside the washing tank. And the microporous film | membrane after a water-washing process is dried, and after applying a wetting agent as needed, it is wound by roll shape.
JP 63-139930 A JP 2002-224539 A

  By the way, in the conventional manufacturing method, when the liquid film or the microporous film is transported in the liquid in the coagulation process or the cleaning process, the pore diameter of the microporous film may change and the hole may be crushed. This is a process in which the liquid film in the coagulation process forms a microporous film, and the pore diameter is easily changed by a slight tension, and the microporous film in the cleaning process is immediately after solidification, so the pore diameter is increased by the tension. It is because it is easy to change. Therefore, the conventional manufacturing method has a problem that it is difficult to obtain a microporous membrane having a desired pore diameter.

  The present invention has been made in view of such circumstances, and it is possible to prevent the pore diameter from being changed in the coagulation process or the washing process, and to produce a microporous film having a desired pore diameter. An object is to provide a manufacturing method and apparatus.

  In order to achieve the above object, the invention according to claim 1 is a method for producing a microporous membrane comprising a submerged transporting step of transporting a microporous membrane or a liquid membrane to be a microporous membrane in a liquid. In the submerged transport step, the microporous film or the liquid film that becomes the microporous film is guided and transported in a non-contact manner by ejecting liquid from a plurality of ejection ports formed on the surface of the turn bar. It is characterized by that.

  According to the present invention, since the microporous film or the liquid film that becomes the microporous film is guided and conveyed by the turn bar in a non-contact manner, the microporous film or the liquid film that becomes the microporous film is applied. The tension can be lowered and the pores of the microporous membrane can be prevented from being crushed.

  Invention of Claim 2 is invention of Claim 1, The said conveyance process in a liquid is a washing | cleaning process of wash | cleaning a microporous film | membrane, While conveying the said microporous film | membrane in the liquid of a washing | cleaning liquid, The cleaning liquid is sprayed from the spray port of the turn bar.

  According to a third aspect of the present invention, in the second aspect of the present invention, the cleaning step is provided immediately after the coagulation step for coagulating the liquid film for forming the microporous film formed on the support. The microporous membrane is washed with a washing liquid. The microporous membrane immediately after solidification has a problem that the pore diameter is easily changed by applying a tension, and such a problem can be solved by applying the present invention.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the submerged transport step is a coagulation step of coagulating a liquid film for forming a microporous film formed on a support, and the liquid film is The formed support is transported into a coagulating liquid, and the coagulating liquid is ejected from an ejection port of the turn bar. The liquid film (microporous film) being coagulated has a problem that the pore diameter is easily changed by applying a tension, and such a problem can be solved by applying the present invention.

  In order to achieve the above object, a fifth aspect of the present invention provides a microporous membrane manufacturing apparatus including a submerged transport device that transports a microporous membrane or a liquid film to be a microporous membrane in a liquid. The submerged transport device includes a turn bar having a plurality of injection holes on a surface thereof, and the liquid film that becomes the microporous film or the microporous film is formed by ejecting liquid from the injection holes of the turn bar. It is guided and conveyed by contact.

  According to the present invention, since the microporous film or the liquid film that becomes the microporous film is guided and conveyed by the turn bar in a non-contact manner, the microporous film or the liquid film that becomes the microporous film is applied. Tension can be reduced. Therefore, according to the present invention, the pores of the microporous membrane can be prevented from being crushed, and a microporous membrane having a desired pore diameter can be produced.

  Preferred embodiments of a method and apparatus for producing a microporous membrane according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 schematically shows the configuration of a microporous membrane manufacturing apparatus according to the present embodiment. A dissolution tank 12 shown in the figure is a tank for preparing a dope for forming a microporous film. Inside the dissolution tank 12, a film forming polymer is dissolved in a solvent to prepare a dope. A jacket 14 is attached to the dissolution tank 12, and the dope in the dissolution tank 12 is maintained at a constant temperature by circulating a heat medium through the jacket 14.

  The dope in the dissolution tank 12 is sent to the die 18 of the coating apparatus by the liquid feed pump 16 in a state where the temperature and the dissolution state are stable. The dope is continuously discharged from the tip of the die 18 toward the belt-like support 20.

  The belt-like support 20 is made of, for example, a polyester film, wound in a roll shape, and attached to the rewinding roller 22. The belt-like support 20 is unwound from the rewinding roller 22 and wound around the drum 24 to be supported. The belt-like support 20 is guided by guide rollers 28 and 28 in a coagulation tank 26 to be described later, and then wound in a roll shape by a take-up roller 34 through a guide roller 30 and a peeling roller 32.

  The dope discharged from the die 18 is cast and applied onto a belt-like support 20 that is wound around and supported by a drum 24. As a result, a liquid film of dope (a film that will later become the microporous film 44) is formed on the surface of the belt-like support 20.

  The belt-like support 20 on which the dope liquid film is formed first travels vertically in the humidity control zone 36 downward. The humidity control zone 36 is formed so that the casing 38 covers the liquid film side surface of the belt-like support 20 from the drum 24 to the coagulation tank 26. Further, inside the humidity control zone 36, the conditioned air is blown in the traveling direction of the belt-shaped support body 20 (that is, downward). Specifically, a humidity control air supply port 36 </ b> A is provided above the humidity control zone 36, and a humidity control air exhaust port 36 </ b> B is provided below the humidity control zone 36. A circulation duct 40 is connected to the air supply port 36A and the exhaust port 36B, and an air conditioner 42 is provided in the circulation duct 40. The air conditioner 42 sucks air from the exhaust port 36B, adjusts the temperature and humidity of the air, and then sends the air to the air supply port 36A. Thereby, humidity control air adjusted to a predetermined greenhouse temperature is sent to the humidity control zone 36, and the inside of the humidity control zone 36 is maintained at a predetermined temperature and humidity.

  In addition, it is preferable to adjust humidity control air within the range of the relative humidity of 10-80% and the wind speed of 0.2-4 m / sec at the temperature of 15-60 degreeC. Moreover, in the humidity control zone 36, it is preferable that the liquid film on the surface of the strip | belt-shaped support body 20 is exposed to humidity control air for 2 to 17 seconds.

  By passing through the humidity control zone 36, the liquid film on the belt-like support 20 undergoes coacervation from the surface toward the inside, and forms a fine coacervation phase from the surface of the liquid film to the inside. That is, in the humidity control zone 36, the non-solvent vapor (for example, moisture) is absorbed from the air while the solvent is evaporated, and a phase separation state is created only in the vicinity of the surface. When formed, micropores can be formed inside the membrane, and relatively large pores can be formed on the surface of the membrane.

  The belt-like support 20 that has passed through the humidity control zone 36 is immersed in the coagulating liquid in the coagulation tank 26 by traveling while being guided by the guide rollers 28 and 28 in the coagulation tank 26. As the coagulation liquid, a liquid (for example, water) that is a non-solvent for the dope polymer and is compatible with the polymer solvent is preferable. By immersing in this coagulating liquid, the liquid film on the surface of the belt-like support 20 is dissolved in the solvent and replaced with the coagulating liquid, and the solvent replacement is performed. Then, the coacervation phase formed in the humidity control zone 36 is fixed as micropores, and at the same time, pores other than micropores are formed by phase separation of the liquid film, and the microporous membrane 44 is formed.

  The microporous membrane 44 is led out from the coagulation tank 26 in close contact with the belt-like support 20. Then, the strip-shaped support 20 is stripped from the microporous film 44 by the peeling roller 32, and the strip-shaped support 20 after stripping is wound around the winding roller 34.

  On the other hand, the peeled microporous film 44 travels by driving the feed roller 46 and is introduced into the washing tank 48. In the washing tank 48, turn bars 50, 50, which will be described later, are provided in the washing solution, and the microporous membrane 44 is guided by the turn bars 50, 50,. Then, when the microporous film 44 travels in the washing liquid in the washing tank 48, the solvent or the like attached to the microporous film 44 is washed away.

  The microporous membrane 44 after cleaning is sent to the drying chamber 52. The drying chamber 52 is provided with drying drums 54, 54 ..., and the microporous membrane 44 is dried by being wound around the drying drums 54, 54 ....

  The microporous film 44 after drying is sent to a wetting agent coating chamber 56. A wetting agent preparation tank 58 is provided in the coating chamber 56, and the wetting agent is prepared by the preparation tank 58. As the wetting agent, a material that is safe even when mixed in foods and pharmaceuticals and can be easily washed away with water is preferable. For example, hydrophilic polymers such as polyvinylpyrrolidone and derivatives thereof, methylcellulose, hydroxymethylcellulose and derivatives thereof, ethylcellulose, hydroxyethylcellulose and derivatives thereof are preferable because they are highly safe, have a high wetting effect, and can be easily washed off with water. . For the same reason, surfactants such as alkyl sulfonates having 6 to 24 carbon atoms and higher fatty acid esters of sucrose are also preferred. As this alkyl sulfonate, sodium salt, potassium salt and lithium salt are preferable, and the fatty acid of the sucrose fatty acid ester preferably has 6 to 24 carbon atoms.

  The wetting agent in the preparation tank 58 is fed through the tube 60 by a pump (not shown). A brush member 62 made of felt or the like is provided at the tip of the tube 60, and this brush member 62 comes into contact with both ends in the width direction of the microporous film 44 guided by the guide rollers 64, 64. It has become. Thereby, the wetting agent is applied to both end portions in the width direction of the microporous film 44.

As a coating amount of the wetting agent, for example, in the case of polyvinylpyrrolidone and derivatives thereof, 1 to 6 g / m ² is preferable, and ² to 4 g / m ² is more preferable. In the case of methyl cellulose, hydroxymethyl cellulose and derivatives thereof, 0.1 to 1 g / m ² is preferable, and 0.2 to 0.6 g / m ² is more preferable. If the surfactant is preferably ^{0.05~0.1g / m 2, 0.1~0.3g / m} 2 is more preferable. The application position need only be a few millimeters from each end of the membrane.

  The method of applying the wetting agent is not limited to the above method. For example, the wetting agent may be applied by bringing a wetting agent soaked in a sponge or cloth into contact with the microporous film 44, a bead coater, You may apply | coat by known application methods, such as a gravure coater and a bar coater.

  The microporous film 44 to which the wetting agent is applied is sent to a wetting agent drying chamber 66. The drying chamber 66 is provided with non-contact conveying drums 68 and 68, and a plurality of holes for blowing out air are provided on the outer peripheral surfaces of the drums 68 and 68. The microporous film 44 is wound around the drums 68 and 68 so as to be supported and conveyed without contact, and the wetting agent on the surface of the microporous film 44 is dried.

  The microporous membrane 44 dried from the wetting agent travels inside the adjustment chamber 70 adjusted to a predetermined temperature and humidity while being guided by the guide rollers 72, 72, and then sent to the winding chamber 74 to form a roll. It is wound up.

  Next, the cleaning process which is a characteristic part of the present invention will be described. FIG. 2 is a cross-sectional view schematically showing the inside of the washing tank 48.

As shown in the figure, five turn bars 50, 50... Are provided in the washing tank 48. A washing liquid supply line 80 is connected to each turn bar 50. The supply line 80 is connected to the discharge port of the pump 82, and the suction port of the pump 82 is communicated with the inside of the washing tank 48 via the suction pipe 84. Therefore, by driving the pump 82, the washing liquid inside the washing tank 48 is sucked and supplied to the turn bars 50, 50.

  FIG. 3 is a perspective view showing the upper turn bar 50 of FIG. The lower turn bar 50 is formed in the same manner as the upper turn bar 50 and is disposed upside down.

  As shown in FIG. 3, the turn bar 50 includes a guide plate 86 that is curved to have a reverse U-shaped cross section, side plates 88 and 88 that form both side surfaces in the width direction of the turn bar 50, and the turn bar 50. The bottom plate 90 that forms the bottom surface is formed in a hollow shape. The aforementioned supply line 80 is connected to the center portion of the bottom plate 90, and the washing liquid is supplied to the inside of the turn bar 50.

  The guide plate 86 is formed with a plurality of injection ports 86A, 86A. The injection ports 86A, 86A,... Are arranged in a staggered pattern at a constant pitch in the vertical and horizontal directions. 3, the hole diameters and pitches are exaggerated in order to avoid the complexity of the drawing.

  The injection ports 86A, 86A... Are formed in a substantially circular shape, and the hole diameter is preferably from 0.1 mm to 5 mm, and more preferably from 0.2 mm to 3 mm. Further, the opening ratio of the guide plate is preferably 1% to 30%, more preferably 3% to 20%. Here, the aperture ratio (%) = (total area of the injection port / area of the guide plate) × 100.

  As shown in FIG. 2, the turn bar 50 configured as described above is arranged in two stages on the upper and lower sides of the washing tank 48. The upper two turn bars 50, 50 are arranged such that the arc-shaped guide plate 86 is on the upper side, and the lower three turn bars 50, 50, 50 are arranged with the arc-shaped guide plate 86 on the lower side. It is arranged to become.

  The microporous film 44 is alternately wound around the arc-shaped guide plate 86 of the lower turn bar 50 and the arc-shaped guide plate 86 of the upper turn bar 50. The above-described injection ports 86A, 86A... Are formed in the guide plate 86, and the washing liquid is injected from the injection ports 86A, 86A, so that the microporous film 44 is guided by the injected washing solution. It is levitated and supported at a position away from the plate 86.

  A restriction plate (not shown) that divides the internal space in the width direction is provided inside the turn bar 50, and this restriction plate may be provided so as to be movable in the width direction of the microporous film 44. In this case, the washing liquid can be sprayed only from the spray holes 86 </ b> A and 86 </ b> A facing the microporous film 44 by matching the position of the regulating plate with the end position in the width direction of the microporous film 44. Therefore, the floating support of the microporous film 44 can be performed more stably.

  According to the cleaning process configured as described above, the microporous film 44 is floated and supported in a non-contact manner by the turn bars 50, 50..., So that when the microporous film 44 is run by the feed roller 46 in FIG. In addition, the microporous membrane 44 runs smoothly in the washing liquid of the washing tank 48. Therefore, it is possible to prevent the tension of the microporous film 44 in the washing solution from increasing. Accordingly, it is possible to prevent a large tension from being applied to the soft microporous film 44 immediately after the solidification step and immediately after the peeling from the belt-shaped support body 20, so that the holes of the microporous film 44 are deformed by the tension. Can be prevented.

  The transport tension of the microporous film 44 is 0.1 to 1.0 kg when the residual solvent amount of the microporous film 44 is 10% or more and 90% or less (in the case of the inside of the washing tank 48 or the like). / Width is preferable. When the lower limit value is not reached, poor conveyance of the microporous film 44 occurs. On the contrary, when the upper limit value is exceeded, the microporous membrane 44, which has a large residual solvent amount and easily deforms the pores, is strongly pulled, so that the pores of the microporous membrane 44 may be deformed. In the present embodiment, since the microporous film 44 in the liquid is transported in a non-contact manner by using the turn bar 50, the microporous film 44 can be transported within the above tension range.

  In addition, it is preferable that the conveyance tension after the amount of residual solvent of the microporous film 44 is less than 10% in the subsequent stage of the water washing step is 1.0 to 4.0 kg / width. If the lower limit is not reached, slack occurs in the microporous film 44 and a conveyance failure occurs. If the upper limit is exceeded, vertical flaws occur in the microporous film 44 and the microporous film 44 is cut. This is because there is a risk of being lost.

  The shape and configuration of the turn bar 50 are not limited to the above-described embodiment, and any configuration can be used as long as the microporous membrane 44 can be supported in a levitating manner by spraying the washing liquid. For example, as shown in FIG. 4, a cylindrical turn bar 92 may be used. The turn bar 92 shown in FIG. 4 has one side 94 connected to a supply line 80 for washing water and the other side (not shown) sealed. Further, the turn bar 92 has a large number of spray ports 96A, 96A,... Formed at equal intervals on the outer peripheral surface 96, and the washing liquid is sprayed from the spray ports 96A, 96A. The turn bar 92 configured as described above may be used in place of the turn bar 50 of FIG. Thereby, since the microporous film 44 is levitated and supported without contact, the microporous film 44 can be transported with low tension. In the turn bar 50 of FIG. 4, the injection ports 96 </ b> A, 96 </ b> A... May be formed on the surface facing the microporous film 44. 2 is formed in the upper half of the outer peripheral surface 96 in the upper half of the outer circumferential surface 96, and the lower turn bar 50 is replaced by the turn bar 92 disposed in place of the upper turn bar 50. In the turn bar 92 disposed in the bottom, the injection ports 96A and 96A may be formed in the lower half of the outer peripheral surface 96.

  In addition, although embodiment mentioned above is an example which applied this invention to the washing | cleaning process immediately after a coagulation | solidification process, it should just be a process which conveys the microporous film | membrane 44 in a liquid, and a pore diameter is applied by applying this invention. The effect which prevents that crushes is acquired.

  Further, the present invention may be applied to a coagulation process in which a liquid film (that is, a liquid film on the belt-like support 20) that becomes the microporous film 44 is conveyed in the liquid. That is, by forming the guide rollers 28 in the coagulation tank 26 with the turn bar 50 or the turn bar 92, the liquid film on the belt-like support 20 may be conveyed without contact. Thereby, since the tension | tensile_strength concerning the strip | belt-shaped support body 20 and a liquid film can be lowered | hung, it can prevent that the hole diameter formed in a liquid film is crushed.

  The dope for forming a microporous film used in the present invention will be described below. The dope contains a film-forming polymer, and the polymer is dissolved in a good solvent, a mixed solvent of a good solvent and a non-solvent, or a mixture of a plurality of solvents having different solubility in the polymer. Produced.

  The type of polymer is not particularly limited and is selected according to the use of the microporous membrane. For example, as the polymer, cellulose acetate, nitrocellulose, polysulfone, sulfonated polysulfone, polyethersulfone, polyacrylonitrile, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol, polycarbonate, organosiloxane -Polycarbonate copolymers, polyester carbonates, organopolysiloxanes, polyphenylene oxides, polyamides, polyimides, polyamideimides, polybenzimidazoles and the like.

  Moreover, although a solvent changes with kinds etc. of a polymer, what is rapidly substituted by coagulating liquid is preferable. In many cases, water and / or an organic solvent compatible with water are used as the coagulation liquid, and therefore it is preferable to use a polar solvent compatible with the coagulation liquid. For example, when the film-forming polymer is polysulfone, dioxane, tetrahydrofuran, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, or a mixed solvent thereof is used. Further, when the polymer is polyacrylonitrile, dioxane, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide and the like are preferable. When the polymer is polyamide, dimethylformamide and dimethylacetamide are preferable, When the polymer is cellulose acetate, acetone, dioxane, tetrahydrofuran, N-methyl-2-pyrrolidone and the like are preferable.

  Examples of the non-solvent when mixing the non-solvent include water, cellosolves, methanol, ethanol, propanol, acetone, tetrahydrofuran, polyethylene glycol, glycerin and the like. The ratio of the non-solvent to the good solvent may be any range as long as the mixed solution can maintain a uniform state, but is preferably 5 to 50% by weight.

  In order to control the porous structure, it is preferable to add an inorganic electrolyte, an organic electrolyte, a polymer, or an electrolyte polymer called a swelling agent to the polymer solution. Examples of swelling agents include metal salts of inorganic acids such as sodium chloride, lithium chloride, sodium nitrate, potassium nitrate, sodium sulfate, and zinc chloride, metal salts of organic acids such as sodium acetate and sodium formate, and polymers such as polyethylene glycol and polyvinyl pyrrolidone. Polymeric electrolytes such as sodium polystyrene sulfonate and polyvinylbenzyltrimethylammonium chloride, ionic surfactants such as sodium dioctyl sulfone succinate and sodium alkylmethyl taurate are used. These swelling agents may be added to the solution alone, but exhibit a remarkable effect when added as an aqueous solution. The amount of the swelling agent added is not particularly limited as long as the addition does not impair the uniformity of the solution, but is usually 0.5% by volume to 10% by volume with respect to the solvent. Furthermore, there is no restriction | limiting in particular also about the density | concentration of a swelling agent, The one where a big concentration has a big effect is acquired, and 1 to 60 weight% is preferable normally.

  The concentration of the polymer solution is preferably 5 to 35% by weight, and more preferably 10 to 30% by weight. This is because when the amount exceeds 35% by weight, the water permeability of the obtained microporous membrane is so small that it has no practical meaning. On the other hand, when the amount is less than 5% by weight, the microporous membrane has sufficient separation ability. This is because cannot be obtained.

  Example 1: Production of microfiltration membrane 15 parts of polysulfone (P-3500, manufactured by Amoco), 70 parts of N-methyl-2-pyrrolidone, 15 parts of polyvinylpyrrolidone, 2 parts of lithium chloride and 1.3 parts of water are uniformly dissolved. Thus, a film forming stock solution was prepared. Using this, casting was performed so that the product thickness was 180 μm, and air at a temperature of 25 ° C., a relative humidity of 50% and a wind speed of 1.0 m / second was applied to the surface of the liquid film cast for 8 seconds, and immediately 25 ° C. It was immersed in a coagulation bath filled with water. In the water washing step after the coagulation bath, 25 ° C. water having a flow rate of 0.3 m / s was sprayed from the nozzle (pore diameter 1 mm) unit shown in FIG. 2 and dried to obtain a microporous membrane.

  Example 2 The test was performed under the same conditions as in Example 1 except that the flow rate was 0.5 m / sec.

  Example 3 The process was performed under the same conditions as in Example 1 except that the flow rate was 0.3 m / sec and the nozzle (hole diameter was 5 mm).

  Example 4 The test was performed under the same conditions as in Example 1 except that the flow rate was 0.5 m / sec and the nozzle (hole diameter was 3 mm) was used.

  Comparative Example 1: The same conditions as in Example 1 were used except that the injection nozzle was not used and the material was conveyed by a roller.

  The microporous film formed under the above conditions was evaluated by visual inspection for wrinkles and scratches during transportation.

表１から分かるように、凝固浴後の水洗工程でロール搬送を行った比較例１では、微孔性膜にしわや傷が発生したのに対し、ノズルから液体を噴射して微孔性膜を非接触で搬送した実施例１〜４では、微孔性膜にしわや傷が発生することを防止することができた。

As can be seen from Table 1, in Comparative Example 1 in which the roll was conveyed in the water washing step after the coagulation bath, wrinkles and scratches were generated on the microporous film, but the liquid was ejected from the nozzle to form the microporous film. In Examples 1 to 4 conveyed in a non-contact manner, generation of wrinkles and scratches on the microporous membrane could be prevented.

Configuration diagram showing a microporous membrane production apparatus according to the present invention Configuration diagram showing the cleaning process of FIG. The perspective view which shows the turn bar of FIG. The perspective view which shows the turn bar different from FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Microporous membrane manufacturing apparatus, 12 ... Dissolution tank, 18 ... Die, 20 ... Strip support, 22 ... Drum, 26 ... Coagulation tank, 36 ... Humidity control zone, 44 ... Microporous membrane, 48 ... Washing with water Tank, 50 ... turn bar, 56A ... injection port, 92 ... turn bar, 96A ... injection port

Claims (5)

In the method for producing a microporous membrane comprising a submerged transport step of transporting a microporous membrane or a liquid membrane to be a microporous membrane in a liquid,
In the submerged transport step, the microporous film or the liquid film that becomes the microporous film is transported in a non-contact manner by ejecting liquid from a plurality of ejection ports formed on the surface of the turn bar. A method for producing a microporous membrane characterized by   The submerged transporting step is a cleaning step of cleaning the microporous membrane, wherein the microporous membrane is transported into the cleaning liquid, and the cleaning liquid is sprayed from the spray port of the turn bar. Item 2. A method for producing a microporous membrane according to Item 1.   The washing step is provided immediately after a coagulation step for coagulating a liquid film for forming a microporous film formed on a support, and the microporous membrane immediately after coagulation is washed with a washing liquid. Item 3. A method for producing a microporous membrane according to Item 2.   The submerged conveyance step is a coagulation step of coagulating a liquid film for forming a microporous film formed on a support, and the support formed with the liquid film is conveyed into a coagulating liquid. The method for producing a microporous membrane according to claim 1, wherein the coagulating liquid is ejected from an ejection port of the turn bar. In a microporous membrane manufacturing apparatus equipped with a submerged transport device that transports a microporous membrane or a liquid membrane to be a microporous membrane in a liquid,
The submerged transport device includes a turn bar having a plurality of injection ports on a surface thereof, and the liquid film to be the microporous film or the microporous film is non-contacted by injecting liquid from the injection port of the turn bar An apparatus for producing a microporous membrane, which is guided and conveyed by

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