JP2003093852A - Method for producing separation membrane and separation membrane forming material and separation membrane obtained thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a separation membrane wherein the diameter of the molecule or microparticle to be separated can be very precisely designed by merely designing the particle diameter of microbodies, to provide a separation membrane having uniform pore diameters, having three-dimensionally formed continuous pores, having a high separation performance depending on the size or shape of the substance to be separated, capable of being irreversibly or reversibly changed in the diameter or shape of pores, and excellent is the property of being general-purpose, and to provide a separation membrane forming material that can precisely, easily, and inexpensively form a separation membrane having uniform pore diameters and pore shapes and having continuous pores. SOLUTION: The method for producing the separation membrane 6 comprises the structure formation step of forming a structure 4 having continuous voids in its inside by filling microbodies 3 on the surface of a support 2; the polymer filling step of filling a polymer 5 into the voids of the structure 4 obtained in the structure formation step; and the separation step of separating the microbodies 3 from the support 2 after the polymer filling step.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a separation membrane for separating molecules and fine particles, a separation membrane forming material obtained by the method, and a separation membrane.

[0002]

2. Description of the Related Art Conventionally, as a separation membrane for separating molecules and fine particles, a porous membrane obtained by stretching a polymer film and a membrane having artificially formed cylindrical pores are known. In addition, as a membrane having a unique molecular recognition ability in the separation membrane, a molecular membrane using cyclodextrin or calixarene (“Molecular Recognition Chemistry” Hiroshi Tsukibe, pages 45-64, Sankyo Publishing Co., Ltd.) and gel chromatography were used. Silica gel and Sephadex ("Analytical Chemistry" Pecsok et.al 62-8
Page 8 Tokyo Kagaku Dojin, “Introduction to Instrumental Analytical Chemistry” Toshiyuki Shono 186
-212 Sankyo Publishing, "Basics and Experiments of Peptide Synthesis" Nobuo Izumiya 143-193 Maruzen) and others. However, the separation membrane has the following problems because the size of the molecule or fine particles to be separated and the size of the separation membrane separates due to the difference in the pore diameter of the separation membrane. Was there.

A porous film obtained by stretching a polymer film has a problem in that the pore size varies and the pores have continuous pores of random size, so that the size of molecules or fine particles to be separated is distributed. It was It is technically extremely difficult for a separation membrane having cylindrical pores with uniform pore diameters to be artificially formed to have a pore diameter corresponding to the size and shape of molecules or fine particles to be separated. I had a problem. Cyclodextrin and calicarene, which are used as molecular membranes with molecular recognition ability, separate the substances to be separated by using the van der waals force and hydrophobic interaction. It is difficult to separate the substance having the property of having different molecular weights, and it is necessary to design individual molecules according to the substance to be separated, which complicates the separation operation and has a problem of poor versatility. The separation method using gel chromatography separates substances by the difference in the osmotic pressure to Sephadex and the difference in the adsorption rate on silica gel, but the separation is caused by variations in the pores inside the gel. However, there is a problem that not only the separability changes but also a large amount of solvent is required at the time of separation, which is not economical.

[0004]

An object of the present invention is to provide a method for producing a separation membrane in which the particle size of molecules or fine particles to be separated can be designed extremely precisely by simply designing the particle size of microparticles. And has a uniform pore size and continuous pores formed three-dimensionally, and has a high separation ability depending on the size and shape of the separation substance, and irreversible or reversible change of the pore size or the pore shape. A separation membrane forming material capable of providing a separation membrane having excellent versatility and capable of accurately and easily forming a separation membrane having a uniform pore diameter and a pore shape and having continuous pores at low cost. To provide.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have designed the particle size of molecules or fine particles to be separated with extremely high precision simply by designing the particle size of microscopic particles. They have found that they can do so and have completed the present invention. That is, the present invention is specified by the matters described in [1] to [16] below.

[1] A structure forming step of forming fine particles on the upper surface of the holding substrate to form a structure having continuous voids therein, and a void of the structure obtained in the structure forming step. A polymer filling step of filling the polymer, and a desorption step of desorbing the holding base material and the microparticles after the polymer filling step,
A method for producing a separation membrane, comprising: As a result, by simply designing the particle size of the fine particles, the particle size of the molecules or fine particles to be separated can be designed very precisely, and a separation membrane having excellent separation performance can be easily manufactured at low cost.

[2] A frame is provided upright on the upper surface of the holding substrate, and the frame is filled with microscopic bodies to form a structure having continuous voids inside. [1] Of the separation membrane of the above. As a result, it is possible to easily form a structure in which minute bodies are densely packed, and as a result, the distribution of pore diameters in the membrane can be minimized and the maximum pore density can be obtained, resulting in a high separation ability. Can be improved.

[3] The method for producing a separation membrane according to [1] or [2], wherein the structure obtained in the structure forming step is sintered at a temperature of 400 to 800 ° C. As a result, the structure formed by filling a large number of microscopic bodies can be fixed, and the accuracy of the separation membrane can be improved.

[4] The polymer porous body obtained in the desorption step is expanded / contracted to have a transformation step of irreversibly changing the pore diameter or the pore shape of the polymer porous body [1] to [1]. [3] The method for producing a separation membrane according to any one of [3]. This makes it possible to adjust the pore diameter or the pore shape in the polymer porous body by applying a force from the outside, and a separation membrane having excellent versatility can be obtained.

[5] The method for producing a separation membrane according to any one of [1] to [4], wherein the fine particles are made of silica. As a result, it is possible to easily obtain a contact between the microscopic bodies, and it is possible to easily perform etching with an etching agent such as hydrofluoric acid or hydrofluoric nitric acid (inorganic acid). Further, since it has excellent heat resistance and chemical resistance, the microscopic body does not deform when the polymer is introduced.

[6] The particle size of the fine particles is 100 nm to 20 μm.
m is the manufacturing method of the separation membrane as described in any one of [1] to [5]. As a result, since the fine particles have the optimum particle size, it is possible to easily form a periodic structure having a close packing structure, and it is possible to design the particle size of the molecules or fine particles to be separated with extremely high precision. Become. Further, when the particle diameters of the fine particles are uniform, the distribution of pore diameters in the membrane becomes the minimum, and the maximum value of the pore density can be obtained, so that the separation ability can be enhanced. Further, the thickness of the separation membrane, that is, the thickness of the structure of the minute body can be controlled, and thus the separation time and the separation accuracy can be changed appropriately.

[7] The holding substrate is at least one selected from silica glass, titanium oxide, silicon, aluminum, titanium, polymethylmethacrylate, polycarbonate, and polystyrene, [1] to [6]. ] The manufacturing method of the separation membrane as described in any one of these. Thereby, since the surface smoothness of the holding base material is high, it is possible to easily form a structure filled with a large number of fine particles and to easily perform an etching operation.

[8] The polymer is poly (methyl methacrylate), poly (hydroxyethyl methacrylate), polystyrene,
The separation membrane according to any one of [1] to [7], which is at least one selected from polycarbonate, polyurethane, polyacrylamide, polybutyl acrylate, epoxy resin, and UV curable resin. Manufacturing method. As a result, it is possible to form a separation membrane composed of a polymer porous body which is excellent in various performances such as separability, durability and chemical resistance.

[9] Releasable holding base material, structure formed on the upper surface of the holding base material and having a continuous void inside, filled with removable fine particles, and void of the structure And a polymer filled in the separation membrane forming material. Thus, the particle size of the molecules or fine particles to be separated can be designed very precisely simply by designing the particle size of the fine particles, and a separation membrane having excellent separation performance can be easily obtained at low cost. In addition, it is possible to change the pore size and the pore density of the structure by changing the particle size of the microparticles or changing the periodic structure, and the separation ability that depends only on the shape of the molecules or fine particles to be separated. It is possible to obtain a separation membrane having

[10] The separation membrane forming material as described in [9], wherein the fine particles are made of silica. As a result, it is possible to easily obtain a contact between the microscopic bodies, and it is possible to easily perform etching with an etching agent such as hydrofluoric acid or hydrofluoric nitric acid (inorganic acid). Further, since it has excellent heat resistance and chemical resistance, the microscopic body does not deform when the polymer is introduced.

[11] The particle size of the fine particles is 100 nm to 20
The separation membrane forming material according to [9] or [10], which has a thickness of μm. As a result, since the fine particles have the optimum particle size, it is possible to easily form a periodic structure having a close packing structure, and it is possible to design the particle size of the molecules or fine particles to be separated with extremely high precision. Become. Further, when the particle diameters of the fine particles are uniform, the distribution of pore diameters in the membrane becomes the minimum, and the maximum value of the pore density can be obtained, so that the separation ability can be enhanced. Further, the thickness of the separation membrane, that is, the thickness of the structure of the minute body can be controlled, and thus the separation time and the separation accuracy can be changed appropriately.

[12] The holding substrate is at least one selected from silica glass, titanium oxide, silicon, aluminum, titanium, polymethylmethacrylate, polycarbonate and polystyrene [9] to [11]. ] The separation membrane forming material as described in any one of these. Thereby, since the surface smoothness of the holding base material is high, it is possible to easily form a structure filled with a large number of fine particles and to easily perform an etching operation.

[13] The polymer is polymethylmethacrylate, polyhydroxyethylmethacrylate, polystyrene,
The separation membrane according to any one of [9] to [12], which is at least one selected from polycarbonate, polyurethane, polyacrylamide, polybutyl acrylate, epoxy resin, and UV curable resin. Forming material. As a result, separability, durability, chemical resistance, etc.
It is possible to form a separation membrane composed of a polymer porous body having various excellent properties.

[14] A separation membrane comprising the holding substrate according to any one of [9] to [13] and a polymer porous body obtained by desorbing fine particles. As a result, it is possible to obtain a separation membrane having a substantially completely uniform pore size, continuous pores being three-dimensionally formed, and having a separation ability that depends only on the shape of the separation substance. Further, by simply designing the particle size of the fine particles, the particle size of the molecules or fine particles to be separated can be designed very precisely, and the separation performance is excellent.

[15] The separation membrane according to [14], wherein the porous polymer body is formed to be expandable and contractible, and the pore diameter or the shape of the porous polymer body is reversibly changed. As a result, since the polymer porous body is formed to be expandable and contractible, the pore diameter or the pore shape is reversibly changed by applying a force from the outside, and the pore diameter or the pore shape in the membrane should be appropriately adjusted. Is possible. Also, the pore size can be changed during the separation to change the size of molecules and fine particles that can pass through the separation membrane.

[16] The separation membrane as described in [14], wherein the porous polymer body expands and contracts, and the pore diameter or the shape of the porous polymer body is irreversibly changed. This allows
By applying force from the outside to the polymer porous body, the pore size or pore shape is irreversibly changed, and the pore shape and pore size in the membrane can be adjusted appropriately, and a separation membrane with excellent versatility can be obtained. You can

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
Since the holding substrate according to the present invention has a periodical structure of microscopic bodies formed on its upper surface, it has strength capable of holding the structure and the polymer and has high surface smoothness, and the polymer is provided in the voids of the structure. Since it is necessary to remove the holding base material after filling, any material may be used as long as it can be etched. Specific examples of the holding substrate include glass such as silica glass, inorganic materials such as titanium oxide and silicon, metals such as aluminum and titanium, polymers such as polymethylmethacrylate, polycarbonate and polystyrene, and the like. It is not limited. In particular, a slide glass having a thin thickness is preferable, which can simultaneously and easily etch the holding substrate and the minute body. When a polymer substrate is used as the holding base material, the type of polymer used for the holding base material needs to be a polymer having a different solubility from the polymer to be filled in the polymer filling step. For example, when polymethylmethacrylate is used as the holding substrate and polymethylmethacrylate is also used in the polymer filling step, it is necessary to add a crosslinking agent to the filled polymer and cure it. The thickness of the holding substrate is preferably 100 μm to 1 mm.
As the thickness becomes thinner than 100 μm, it tends to be difficult to handle, and as the thickness becomes thicker than 1 mm, the etching time becomes longer, a large amount of etching solvent is required, and the economy tends to be poor. . The surface roughness of the holding substrate according to the present invention is 0 to 1 μm,
It is preferably 0 to 100 nm. Since the surface roughness is preferably equal to or smaller than the particle size of the fine particles used, it is appropriately changed depending on the particle size of the fine particles. Here, the surface roughness is 100.
If it is larger than nm, the structure can be sufficiently formed, but it tends to cause disorder of regularity and reduce the pore density. In particular, if it is larger than 1 μm, these tendencies become remarkable.

In the step of forming the structure according to the present invention, it is possible to erect the frame portion on the holding base material.
The structure can be formed by simply leaving the dispersion solution of the microspheres on the holding substrate without using the frame. As a method of standing the frame portion according to the present invention on the holding substrate, pressure bonding,
A method of sealing with silicone grease or the like and a method of fixing with an adhesive or the like are used, but the crimping method is preferably used because the frame portion can be easily removed from the holding base material. Here, the type of adhesive used is not limited. Further, in the method of removing the frame part from the holding base material, in crimping, since the frame part is fixed by applying a load from above, the frame part can be easily removed by removing the load. Also, as for the method of sealing with silicone grease or the like, it can be easily removed by pulling the frame portion away from the holding base material. Further, regarding the method of fixing with an adhesive or the like, it can be removed by heating or by breaking the frame portion. The shape of the frame portion according to the present invention may be any shape such as a cylindrical shape or a prismatic shape as long as the structure can be formed. The material of the frame portion according to the present invention is
Examples thereof include, but are not limited to, silicone rubber, glass, polyethylene, polyethylene terephthalate, polycarbonate, polystyrene and the like.

The particle size of the fine particles according to the present invention is from 50 nm to
It is 100 μm, preferably 100 nm to 20 μm.
Here, as the particle size becomes smaller than 100 nm, the sedimentation speed of the fine particles becomes very slow, so that it becomes difficult to fill the fine particles and it becomes difficult to form a periodic structure having a close-packed structure. It can be seen that as the particle size becomes larger than 20 μm, it tends to be difficult to manufacture the structure. Especially if the particle size is smaller than 50 nm or 100
If it is larger than μm, these tendencies become remarkable. The shape of the microparticles according to the present invention may be any shape as long as a large number of microparticles can be filled on the holding substrate and a structure having voids inside can be formed. Specific shapes are spherical, elliptical,
Examples thereof include a cylindrical shape, a hollow shape, and a golf ball shape, but are not limited thereto. In particular, in order to design the particle diameter of the molecules and fine particles to be separated with extremely high precision and obtain a separation membrane having excellent separation performance, the spherical shape is preferable. As the material of the fine particles according to the present invention, in addition to silica, polymers such as polystyrene and polymethylmethacrylate can be used as long as they can be etched with an organic or inorganic solvent.
In particular, when silica is used, it is possible to easily obtain a contact point between microparticles because the sedimentation speed is fast. Also, since the solvent introduced and the solvent that dissolves are different, it is possible to selectively etch only silica. It is preferable because it is possible. For example, silica microspheres with a size of 100 nm to 10 μm are
Easily forms a periodic microsphere structure (silica opal) having a close-packed structure. In this microsphere structure, about 26% of continuous voids are present in the spaces between the microspheres. By filling the voids with the polymer, a composite structure of silica and polymer filled with the polymer at a filling rate of about 26% can be obtained.
When this composite was treated with an aqueous solution of hydrofluoric acid and the silica microspheres were removed, the polymer with a filling rate of 26% and 74%
A polymer porous body (polymer inverse opal) having voids is obtained.

The structure filled with a large number of fine particles of silica is prepared, for example, from a solution in which silica microspheres are suspended in water, by a natural sedimentation method or a forced sedimentation method by centrifugal force. The structure composed of silica microspheres having a periodic structure thus obtained is preferably dried by removing water. After drying, the structure can be used as is,
Depending on the type of polymer used for the holding substrate, it may be used after sintering at a temperature of 400 to 800 ° C. When polycarbonate is used for the holding substrate, sintering cannot be performed. Here, as the sintering temperature becomes lower than 400 ° C., it tends to become difficult to fix the structure, and as it exceeds 800 ° C., the structure tends to deform. Since the microparticles according to the present invention need to be removed after the voids of the structure are filled with the polymer, contacts between the microparticles are necessary. The polymer according to the present invention is resistant to the etching agent used for the holding substrate and the microscopic body, and has strength enough to maintain the ordered structure composed of the polymer porous body, and is resistant to the solvent of the substance to be separated. It may be. Specific polymers include polymethylmethacrylate, polyhydroxyethylmethacrylate, polystyrene, polycarbonate, polyurethane, polyacrylamide, polybutyl acrylate,
Examples thereof include epoxy resin and UV curable resin, but are not limited thereto.

In the polymer filling step according to the present invention,
The method for filling the voids inside the structure with a polymer is as follows: photopolymerization (radical) polymerization, heat melting in the case of polyacrylamide, photo (radical) polymerization, heat melting in the case of polybutyl acrylate, heat fusion, Light (radical) polymerization, heat melting, light (radical) polymerization in the case of poly (hydroxyethyl methacrylate), heat melting, light (radical) polymerization in the case of polystyrene, heat melting, heat melting in the case of polycarbonate, epoxy resin Thermal polymerization, photopolymerization in the case of UV curable resin, thermal polymerization in the case of polyurethane are used. For example, when polymethylmethacrylate is used as the polymer, a monomer (methylmethacrylate) containing 25% polymer (polymethylmethacrylate) in a weight fraction as a thickener (polymethylmethacrylate) is introduced, and The monomer is polymerized using an ultraviolet light source (mercury lamp). When an epoxy resin is used, a curing agent (polyamide amine) is introduced, and this polymer is polymerized by thermal polymerization. Examples of the thickener used when filling the polymer according to the present invention include polymethyl methacrylate, poly (hydroxyethyl methacrylate), polystyrene, polycarbonate, polyester, etc., but are not limited to these as long as the polymer is soluble in the monomer. Not something. Examples of the curing agent (reaction initiator) used when filling the polymer according to the present invention include ter-butyl hydroperoxide, azobisisobutyronitrile, and dibenzoyl disulfide, but are not limited thereto. Absent. Examples of the cross-linking agent used when filling the polymer according to the present invention include, but are not limited to, triethylene glycol dimethacrylate, divinylbenzene, phthalic anhydride and diethylenetriamine. The polymer can be filled not only with the voids of the structure but also with the side surface of the structure surrounding the polymer.

As the etching agent used in the desorption process for desorbing the holding base material and the fine particles, hydrofluoric acid, hydrofluoric nitric acid in the case of silica glass, hot concentrated sulfuric acid in the case of titanium oxide,
Sodium hydroxide, aqua regia for silicon, alkali hydroxide, hydrochloric acid for aluminum, dilute sulfuric acid, nitric acid, hydrofluoric acid for titanium, toluene for polymethylmethacrylate, chloroform, for polycarbonate, In the case of chloroform, acetone, DMF and polystyrene, toluene, chloroform and the like are used respectively.
The polymer porous body according to the present invention is uniaxially stretched, biaxially stretched, compressed, expanded and contracted by applying an external force such as torsional strain,
It can be reversibly or irreversibly deformed to change the internal pore diameter and pore shape reversibly or irreversibly. The deformation step according to the present invention is a step of expanding and contracting the polymer porous body to irreversibly change the pore diameter and the pore shape. When the polymer porous body is reversibly changed, the pore diameter and the pore shape can be reversibly changed even during the separation. Here, "reversible" does not mean a completely reversible deformation, but the polymer porous body is formed to be expandable and contractible, and its pore diameter or pore shape is changed by an external force, etc. , A state in which the polymer porous body is substantially restored and returns to the original pore diameter or pore shape. The polymer used for the separation membrane in which the polymer porous body is irreversibly deformed is required to have the above-described conditions, and also needs to be deformed by an external force, and has a strength that does not collapse the internal structure during the deformation. Becomes Specific examples of such a polymer include, but are not limited to, polymethylmethacrylate, polystyrene, and polycarbonate. The polymer used for the separation membrane in which the polymer porous body is reversibly deformed has the above-mentioned conditions, and also exhibits elasticity in the temperature range when separating the separation substance, and this deformation is not limited to deformation by an external force, Swelling deformation due to a solvent and thermal deformation due to temperature are possible, and strength is required to such an extent that the internal structure does not collapse during deformation. Specific examples of such polymers include, but are not limited to, poly (hydroxyethyl methacrylate) and polyurethane. The polymer of the present invention is blended with additives such as stabilizers, ultraviolet absorbers, lubricants, bluing agents, pigments, colorants, antioxidants, antistatic agents, etc. within a range not impairing the object of the present invention. Good.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited thereto. Example 1 FIG. 1 is a manufacturing process diagram of a separation membrane in one example of the present invention. As shown in FIG. 1, a cylindrical silicone rubber 7 as a frame was pressure-bonded onto a cover glass (silica glass) 2 as a holding substrate. A solution 8 in which spherical silica microparticles (hereinafter referred to as silica microspheres) 3 having a particle diameter of 285 nm are suspended in water is placed in the silicone rubber 7 and allowed to stand, and the silica microspheres are prepared by a natural sedimentation method. 3 was allowed to settle to prepare a structure 4 in which a large number of silica microspheres 3 were periodically packed (hereinafter referred to as silica microsphere periodic structure) 4 (FIG. 1).
(1)). After that, the water was removed and dried, and the silicone rubber 7 was removed (FIG. 1 (2)). Then, a monomer (methyl methacrylate) containing 25% of polymer (polymethylmethacrylate) as a thickener (polymethylmethacrylate) in a weight fraction as a thickener (polymethylmethacrylate) is placed in the voids in the silica microsphere periodic structure 4. This monomer was introduced and polymerized using an ultraviolet light source (mercury lamp) (Fig. 1 (3)). As a result, the separation film forming material 1 as shown in FIG. 2 was formed. FIG. 2 is an enlarged cross-sectional view of the separation membrane forming material in one embodiment of the present invention. Then, the holding substrate and the silica microspheres were dissolved in an 8% hydrofluoric acid aqueous solution as an etching agent to prepare a separation membrane composed of a polymer porous body as shown in FIGS. 3 and 4 (FIG. 1 (4)). ). FIG. 3 is an enlarged cross-sectional view of the separation membrane according to the embodiment of the present invention, and FIG. 4 is an enlarged plan view of the separation membrane according to the embodiment of the present invention.

Example 2 Cylindrical silicone rubber was pressure-bonded onto titanium oxide serving as a holding substrate. Particle size 1 in water in this silicone rubber
A solution in which silica microspheres having a diameter of 00 nm were suspended was placed and allowed to stand, and the silica microspheres were settled by the forced sedimentation method by centrifugal force to prepare a silica microsphere periodic structure. Then, the water was removed and the product was dried and the silicone rubber was removed. The obtained silica microsphere periodic structure was sintered and fixed at a temperature of 600 ° C. Then, the epoxy resin and the curing agent (polyamide amine) are placed in the voids in the silica microsphere periodic structure.
Was introduced and the polymer was polymerized by thermal polymerization. Then, the holding substrate was dissolved in hot concentrated sulfuric acid as an etching agent and the silica microspheres were dissolved in an 8% aqueous solution of hydrofluoric acid as an etching agent to prepare a separation membrane made of a polymer porous body.

Example 3 A silica microsphere periodic structure was prepared by allowing water droplets of a solution in which silica microspheres having a particle size of 20 μm were suspended in water to stand still on silicone as a holding substrate. After that, the water was removed and the product was dried. Then, the polymer (polycarbonate) was heated to 220 ° C., melted and introduced into the voids in the above-mentioned silica microsphere periodic structure. After that, the holding substrate is treated with aqua regia which is an etching agent, and the silica microspheres are treated with an etching agent.
% Hydrofluoric acid aqueous solution, respectively, to prepare a separation membrane composed of a polymer porous body.

Example 4 Cylindrical silicone rubber was pressure-bonded onto aluminum as a holding substrate. A solution in which silica microspheres having a particle size of 552 nm were suspended in water was placed in the silicone rubber, allowed to stand, and the silica microspheres were allowed to settle by a natural sedimentation method to prepare a silica microsphere periodic structure. Then, the water was removed and the product was dried and the silicone rubber was removed. The obtained silica microsphere periodic structure was sintered and fixed at a temperature of 400 ° C. Then, the polymer (polycarbonate) was heated to 220 ° C., melted and introduced into the voids in the above-mentioned silica microsphere periodic structure. Then, the holding substrate and the silica microspheres were dissolved in an 8% hydrofluoric acid aqueous solution as an etching agent to prepare a separation membrane made of a polymer porous body.

Evaluation Example 1 Examples 1 to 2 and Example 4 are a method for manufacturing a separation membrane which is carried out by using a frame portion in the structure forming step, and Example 3 is carried out without using the frame portion. It is a manufacturing method of a separation membrane. Regarding the separation membrane composed of the polymer porous body obtained in Examples 1 to 4, a scanning electron microscope (FE-SEM JSM-6340) was used.
It was confirmed by a model JEOL Co., Ltd.). The results are shown in FIGS. 5 and 6. 5 is an electron micrograph showing the separation membrane in Example 1 of the present invention, and FIG. 6 is Example 4 of the present invention.
3 is an electron micrograph showing the separation membrane in FIG. As is apparent from FIG. 5, the diameter of the voids inside the membrane of Example 1 is approximately equal to the particle diameter of silica microspheres of 285 nm, and the pores between the spherical voids have a pore diameter of about 50 nm. I understand. Further, as is clear from FIG. 6, the diameter of the voids inside the membrane is approximately equal to the particle size of silica microspheres of 552 nm, and the pores between the spherical voids have a pore diameter of about 110 nm. Recognize. That is, it can be seen that the separation membrane obtained in Example 4 has a uniform pore diameter and pore shape. Also in Examples 2 and 3, it can be seen that the diameter of the voids inside the film is substantially equal to the particle diameter of the silica microspheres. That is, the separation membranes obtained in Examples 1 to 3 were
It can be seen that the polymer has a uniform pore diameter and pore shape regardless of the type of polymer used. Furthermore, when ethanol was placed on the upper surface of the separation membrane of Examples 1 to 4 and the lower surface side was sucked, it was confirmed that ethanol flows. As a result, it can be seen that the polymer porous body has continuous pores.

Example 5 Cylindrical silicone rubber was pressure-bonded onto silica glass (cover glass) as a holding substrate. A solution in which silica microspheres having a particle size of 285 nm were suspended in water was placed in the silicone rubber, and the solution was allowed to stand, and the silica microspheres were allowed to settle by a natural sedimentation method to prepare a silica microsphere periodic structure. Then, the water was removed and the product was dried and the silicone rubber was removed. The obtained silica microsphere periodic structure was sintered and fixed at a temperature of 800 ° C. Next, a thickener (polymethylmethacrylate) is added to the voids in the above-mentioned silica microsphere periodic structure.
A monomer (methyl methacrylate) containing 25% by weight of the polymer (polymethylmethacrylate) was introduced, and this monomer was polymerized using an ultraviolet light source (mercury lamp). Then, the holding substrate and silica microspheres
Dissolve in an 8% hydrofluoric acid aqueous solution that is an etching agent,
A separation membrane made of a polymer porous body was prepared. The obtained porous polymethylmethacrylate was uniaxially stretched up to 1.5 times in a 90 ° C water bath using a stretching machine (manufactured by Toa Shokai) to irreversibly deform the separation membrane. In this example, the separation membrane was stretched in a direction substantially parallel to the surface. FIG. 7 is an enlarged sectional view showing a state in which the separation membrane in one embodiment of the present invention is irreversibly deformed. In the figure, ⇒ indicates irreversible deformation.

Evaluation Example 2 With respect to the separation membrane composed of the polymer porous body obtained in Example 5, a scanning electron microscope (FE-SEM JSM-634) was used.
It was confirmed by Type 0 JEOL Co., Ltd.). The result is shown in Fig. 8.
Shown in. FIG. 8 is an electron micrograph showing a separation membrane in Example 5 of the present invention. As is clear from FIG. 8, in the separation membrane made of the polymer porous body obtained in Example 5, the spherical voids are deformed into elliptic spheres, and thus the pores between the elliptic spheres are enlarged. At this time, the number of pores between the ellipsoidal spheres is 5
It is about 0 nm to 80 nm, and this pore size can be adjusted by changing the stretching ratio. Further, it is found that even when the polymer porous body is removed from the stretching device, the state is maintained and fixed. It can be seen that the separation membrane of this example lies in a plane parallel to the stretching direction, and each pore is deformed into an elliptical shape. Furthermore, when hexane was placed on the upper surface of the separation membrane and the lower surface side was sucked, it was confirmed that hexane flowed. As a result, it can be seen that the polymer porous body has continuous pores.

Example 6 Cylindrical silicone rubber was pressure-bonded onto silica glass (cover glass) as a holding substrate. A solution in which silica microspheres having a particle size of 285 nm were suspended in water was placed in the silicone rubber, and the solution was allowed to stand, and the silica microspheres were allowed to settle by a natural sedimentation method to prepare a silica microsphere periodic structure. Then, the water was removed and the product was dried and the silicone rubber was removed. The obtained silica microsphere periodic structure was sintered and fixed at a temperature of 600 ° C. Next, a thickener (polymethylmethacrylate) is added to the voids in the above-mentioned silica microsphere periodic structure.
A monomer (methyl methacrylate) containing 25% by weight of the polymer (polymethylmethacrylate) was introduced, and this monomer was polymerized using an ultraviolet light source (mercury lamp). Then, the holding substrate and silica microspheres
Dissolve in an 8% hydrofluoric acid aqueous solution that is an etching agent,
A separation membrane made of a polymer porous body was prepared. The obtained porous polymethylmethacrylate was uniaxially stretched up to 1.5 times in a 90 ° C water bath using a stretching machine (manufactured by Toa Shokai) to irreversibly deform the separation membrane. In this example, the separation membrane was stretched in a direction substantially perpendicular to the surface.

Evaluation Example 3 With respect to the separation membrane composed of the polymer porous body obtained in Example 6, a scanning electron microscope (FE SEM JSM 634) was used.
It was confirmed by Type 0 JEOL Co., Ltd.). The result is shown in Figure 9.
Shown in. FIG. 9 is an electron micrograph showing a separation membrane in Example 6 of the present invention. As is clear from FIG. 9, in the separation membrane made of the polymer porous body obtained in Example 6, the spherical voids are deformed into elliptic spheres, so that the pores between the elliptic spheres are enlarged. At this time, the number of pores between the ellipsoidal spheres is 5
It is about 0 nm to 80 nm, and this pore size can be adjusted by changing the stretching ratio. Further, it is found that even when the polymer porous body is removed from the stretching device, the state is maintained and fixed. It can be seen that the separation membrane of this example lies in a plane perpendicular to the stretching direction, and each pore is deformed into an elliptical shape. Furthermore, when hexane was placed on the upper surface of the separation membrane and the lower surface side was sucked, it was confirmed that hexane flowed. As a result, it can be seen that the polymer porous body has continuous pores.

Example 7 Cylindrical silicone rubber was pressure-bonded onto polycarbonate, which is a holding substrate. A solution in which silica microspheres having a particle size of 285 nm are suspended in water is placed in the silicone rubber, allowed to stand, and the silica microspheres are sedimented by a forced sedimentation method by centrifugal force to prepare a silica microsphere periodic structure. did. Then, the water was removed and the product was dried and the silicone rubber was removed. Next, polyethylene glycol and hexamethylene diisocyanate were mixed in advance in the voids in the silica microsphere periodic structure and heated at 85 ° C. for 24 hours to prepare a prepolymer. The obtained prepolymer and the cross-linking agent 1,1,1, -tris (hydroxymethyl) propane (also known as trimellilol propane) were introduced to prepare the prepolymer 8
It was thermally polymerized at 0 ° C. for 24 hours to be crosslinked. Then, the holding substrate was dissolved with chloroform as an etching agent and the silica microspheres were dissolved with an aqueous solution of 8% hydrofluoric acid as an etching agent to prepare a separation membrane made of a polymer porous body. The resulting porous polyurethane was reversibly deformed in a uniaxial direction in a 20 ° C. water bath using a stretching device (manufactured by Toa Shokai) in the separated solution.

Evaluation Example 4 The separation membrane obtained in Example 7 is deformed when an external force is applied and stretched, and the pore diameter and shape of the inside of the membrane change, but when the force is released, it is restored. The pore size and shape of Further, in the separation membrane of this example, the spherical voids are transformed into elliptic spheres in the separation solution, and thus the pores between the elliptic spherical voids are expanded. At this time, the pores between the voids of the ellipsoid are 50n.
The pore size is about m to 80 nm, and the pore size can be adjusted during the separation by reversibly changing the stretching ratio. Further, it was confirmed that methanol was allowed to flow by placing methanol on the upper surface of the separation membrane and sucking the lower surface side, and it was found that the polymer has continuous pores.

[0039]

According to the method for producing a separation membrane of the present invention, the particle diameter of the molecules or fine particles to be separated can be designed extremely precisely by simply designing the particle diameter of the fine particles, and a separation membrane having excellent separation performance can be obtained. It can be easily manufactured at low cost. In addition, it is possible to easily form a structure in which microscopic bodies are densely packed, and as a result, the distribution of pore diameters in the film is minimized,
Further, the maximum value of the pore density can be obtained, and the separation ability can be improved. According to the separation membrane forming material of the present invention,
It is possible to change the pore size and the pore density of the structure by changing the particle size of the microparticles or the periodic structure, and it has a separation ability that depends only on the shape of the molecules and particles to be separated. A separation membrane can be obtained. According to the separation membrane of the present invention, it is possible to obtain a separation membrane having a substantially completely uniform pore diameter and three-dimensionally formed continuous pores, and having a separation ability that depends only on the shape of the separation substance. it can. Further, it is possible to irreversibly or reversibly change the pore diameter or the pore shape by applying a force to the separation membrane from the outside, and it is possible to appropriately adjust the pore diameter or the pore shape in the membrane, which is excellent in versatility. . When the separation membrane is formed to be expandable and contractible, the pore size can be changed even during the separation to change the size of molecules and fine particles that can pass through the separation membrane.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a separation membrane according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a separation membrane forming material according to an embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of a separation membrane according to an embodiment of the present invention.

FIG. 4 is an enlarged plan view of a separation membrane according to an embodiment of the present invention.

FIG. 5 is an electron micrograph showing the separation membrane in Example 1 of the present invention.

FIG. 6 is an electron micrograph showing a separation membrane in Example 4 of the present invention.

FIG. 7 is an enlarged cross-sectional view showing a state in which the separation membrane in one embodiment of the present invention is irreversibly deformed.

FIG. 8 is an electron micrograph showing a separation membrane in Example 5 of the present invention.

FIG. 9 is an electron micrograph showing a separation membrane in Example 6 of the present invention.

[Explanation of symbols]

1 Separation film forming material 2 cover glass 3 Silica microspheres 4 structures 5,5a polymer 6,6a Separation membrane 7 Silicone rubber 8 Silica microsphere dispersion solution

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01D 71/54 B01D 71/54 C08J 9/26 101 C08J 9/26 101 CER CE CEZ CEZ // C08L 101: 00 C08L 101: 00 F term (reference) 4D006 GA02 MA03 MA27 MA31 MC37X MC38X MC49X MC50X MC53X NA54 4F074 AA32 AA48 AA50 AA64 AA70 AA78 CB03 CB13 CC02Z CC03Z CC04X CC06X CC12X DA59

Claims (16)

[Claims] 1. A structure-forming step of forming microstructures on the upper surface of a holding substrate to form a structure having continuous voids therein, and a polymer in the voids of the structure obtained in the structure-forming step. A method for producing a separation membrane, comprising: a polymer filling step of filling the polymer; and a desorption step of desorbing the holding base material and the fine particles after the polymer filling step. 2. The structure according to claim 1, wherein a frame portion is erected on the upper surface of the holding substrate, and the frame body is filled with a minute body to form a structure having continuous voids inside. Method for manufacturing separation membrane. 3. The structure obtained in the structure forming step is sintered at a temperature of 400 to 800 ° C.
Or the method for producing the separation membrane according to item 2. 4. The method according to claim 1, further comprising a deformation step of expanding and contracting the polymer porous body obtained in the desorption step to irreversibly change the pore diameter or the pore shape of the polymer porous body. The method for producing the separation membrane according to any one of the above. 5. The method for producing a separation membrane according to claim 1, wherein the microscopic body is made of silica. 6. The method for producing a separation membrane according to claim 1, wherein the fine particles have a particle size of 100 nm to 20 μm. 7. The holding substrate is silica glass, titanium oxide,
7. At least one selected from silicon, aluminum, titanium, polymethylmethacrylate, polycarbonate and polystyrene.
The method for producing the separation membrane according to any one of 1. 8. The polymer is at least one selected from polymethyl methacrylate, polyhydroxyethyl methacrylate, polystyrene, polycarbonate, polyurethane, polyacrylamide, polybutyl acrylate, epoxy resin, and UV curable resin. The method for producing a separation membrane according to any one of claims 1 to 7. 9. A detachable holding base material, a structure formed on the upper surface of the holding base material and having a continuous void inside, which is filled with detachable fine particles, and in the void of the structure body. And a filled polymer. 10. The separation membrane forming material according to claim 9, wherein the fine particles are made of silica. 11. The fine particles have a particle size of 100 nm to 20 μm.
The separation membrane forming material according to claim 9 or 10, wherein 12. The holding substrate is at least one selected from silica glass, titanium oxide, silicon, aluminum, titanium, polymethylmethacrylate, polycarbonate and polystyrene. The separation membrane forming material according to any one of items. 13. The polymer is polymethylmethacrylate,
13. At least one selected from poly (hydroxyethyl methacrylate), polystyrene, polycarbonate, polyurethane, polyacrylamide, polybutyl acrylate, epoxy resin, UV curable resin, any one of claims 9 to 12. The separation membrane forming material as described in 1. 14. A separation membrane comprising the holding substrate according to any one of claims 9 to 13 and a polymer porous body obtained by desorbing the minute bodies. 15. The separation membrane according to claim 14, wherein the polymer porous body is stretchably formed, and the pore diameter or the pore shape of the polymer porous body is reversibly changed. 16. The separation membrane according to claim 14, wherein the porous polymer body expands and contracts, and the pore diameter or the shape of the porous polymer body is irreversibly changed.