JP3287415B2 - Method for producing porous polymer membrane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to filtration and separation of proteins, colloids, bacteria, viruses, salts, etc. in various separation processes such as food industry, pharmaceutical industry, electronics industry, wastewater treatment, artificial organs, and desalination of seawater. Ultrafiltration membrane, reverse osmosis membrane, microfiltration membrane, gas-liquid contact diaphragm used for the purpose of
The present invention relates to a porous film such as a degassing film and an air supply film and a method for producing the same.

[0002]

2. Description of the Related Art As a method for producing a porous membrane, a so-called wet method is used in which a polymer is dissolved in a solvent, formed into a film, and then brought into contact with a non-solvent to solidify the polymer.
In some cases, a polymer is mixed with a substance that can be extracted with a non-solvent of the polymer, and the mixture is extracted after forming a film.

However, in these methods, in addition to the disadvantage that the production rate is low, it is necessary to use a non-crosslinkable polymer that is soluble in a solvent because it is necessary to prepare a polymer solution.
There were problems in strength, creep resistance, heat resistance, and chemical resistance.

[0004] On the other hand, there is a so-called melting method in which a crystalline polymer is melt-extruded to form a film by stretching after stretching, but there is a similar drawback because the material needs to be a thermoplastic polymer.

In order to solve these problems, it is desired to produce a film having a crosslinked structure. As a method for making this possible, Japanese Patent Publication No. 56-34329 and Japanese Patent Publication No.
No. 65220, a polymerizable monomer and / or oligomer is polymerized in the presence of a non-solvent which acts as a solvent for the monomer and / or oligomer and does not swell the polymer formed from the monomer. A method for producing a porous membrane having a crosslinked structure is described.

[0006]

[Problems to be solved by the invention]
According to the methods disclosed in JP-A-34329 and JP-B-63-65220, a porous film having a high production rate and excellent strength, heat resistance and chemical resistance can be obtained, but the polymerizable solution before polymerization is 100 cps. It has the following low viscosity and is greatly restricted by its film forming method. The difficulty is particularly severe in the production of hollow fiber membranes where it is desirable to use a high-viscosity membrane-forming solution. In addition, the polymerizable solution is polymerized in a state where the polymerizable solution is applied to a porous support such as a nonwoven fabric, cloth, paper, or a microfiltration membrane, and when the porous membrane backed by these supports is manufactured, the polymerizable solution is also used. Has a low viscosity of 100 cps or less, the permeation into the porous support is excessive, which is not preferable.

That is, as expected from the principle of forming a porous structure by removing a non-solvent from the obtained polymer, in order to obtain a porous membrane having a high pore volume, it is necessary to prepare a porous membrane before polymerization. Non-solvent volume fraction in solution is 15%
More preferably, 30% or more is required. At this time, if an alkyl ester, heptane, isooctane, adipic acid ester, butanol, or the like as recommended in the above patent is used as a non-solvent, the viscosity of the polymerizable solution becomes 100 cps.
It has the following low viscosity.

JP-B-56-34329 discloses that the viscosity can be adjusted by adding a thickening agent such as finely divided silica or bentonite to a low-viscosity polymerizable solution. Thickeners exhibit a thickening effect by being dispersed in a solution, and since their particle size is several μm to several hundred μm, the distribution of pores in the obtained porous membrane is Is very inhomogeneous. Moreover, these thickening effects have so-called thixotropic properties, and the thickening effect is not effective in a film forming method in which a large shear force acts on a film forming solution such as a hollow fiber film forming.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention.

That is, the present invention relates to a monomer and / or oligomer (A) polymerizable by irradiation with energy rays.
Is compatible with the monomer and / or oligomer (A), is incompatible with the polymer produced by irradiating the monomer and / or oligomer (A) with energy rays, and is inert to energy rays. A method for producing a porous polymer membrane, comprising: irradiating a uniform polymerizable liquid mixed with an oligomer (B) with an energy beam, and then removing the oligomer (B); The polymerizable monomer and / or oligomer (A) is dissolved in a homogeneous solution of the monomer and / or oligomer (A) or the monomer and / or oligomer (A) and a solvent, and the monomer and / or oligomer (A) is dissolved. A) a polymer that is incompatible with the polymer produced by irradiating the energy beam on After irradiation with energy rays to a uniform polymerizable liquid mixture of a (C), there is provided a method for producing a porous polymer membrane and removing the polymer (C).

[0011] The porous polymer membrane obtained by the present invention comprises:
It has a large number of communication holes having an average pore diameter of 0.02 μm or more and 10 μm or less. A porous membrane having communication holes is one in which individual minute voids in the membrane are in communication with each other and liquid can permeate from one side of the membrane to the other. The pore size may be uniform in the membrane or may have a pore size distribution. For example, it may have a pore size distribution in the thickness direction of the film. Having a pore size distribution in the thickness direction of the film means that the pore size changes continuously or discontinuously in the film thickness direction. For example, if the pore size of the pores increases or decreases continuously from one surface of the film to the other surface, if the pore size increases or decreases discontinuously from one surface of the film toward the other surface, If there is a layer of the smallest pore size on both surfaces of the membrane, and the pore size increases continuously or discontinuously from both surfaces of the membrane toward the inside of the membrane, the smallest pore size is formed in the internal part of the membrane. There may be a layer and the pore size increases continuously or discontinuously from both sides of this layer toward both surfaces of the membrane.

The communicating holes in the membrane of the present invention are formed at substantially the same time when the monomer and / or oligomer (A) polymerizable by irradiation with energy rays are polymerized by irradiation with energy rays. It does not form a polymer as seen in the wet method and other film forming methods. The communication holes may be provided as gaps between the particles of the polymer adhered to each other,
It may be given as a gap between polymers deposited in a three-dimensional network, or it may have a long oval or slit-like shape in the fiber direction. There is no so-called macrovoid having a diameter of 10 μm or more and being long in the thickness direction of the film.
The shape of these holes can be determined by observing the cross section or the surface of the film with an electron microscope. The pore diameter and porosity of the communication holes present in the membrane can be measured by a mercury intrusion method.

In the present invention, the average pore size refers to a peak of a pore size distribution measured by a mercury intrusion method. The average pore size can be arbitrarily designed according to the purpose of use of the membrane. The polymer of the porous polymer membrane obtained according to the present invention can be any of a non-cross-linked type and a cross-linked type, and the cross-linking density can be arbitrarily controlled by selecting a monomer and / or an oligomer. It is preferable that the porous membrane obtained by the present invention is a crosslinked type in terms of pressure tightness, heat resistance, solvent resistance, chemical resistance, etc., but it is particularly necessary to reduce the residual amount of unreacted monomers and oligomers. When there is a problem or when it is necessary to reduce the residual double bond in the film, a non-crosslinked film can be formed by using a monofunctional monomer and / or oligomer. Non-crosslinked films tend to be inferior in heat resistance and creep properties, and those having an excessively high degree of crosslinking lack flexibility and strength, and at the same time, the residual amount of unreacted monomers and oligomers increases. Whether the membrane is cross-linked or non-cross-linked
It can be determined by the presence or absence of a solvent that can dissolve the film. In the case of a cross-linked type, it may swell in a gel state but does not dissolve.

The swelling referred to herein is a concept defined for a crosslinked polymer, and refers to a phenomenon that occurs when the crosslinked polymer is immersed in a solvent that dissolves a non-crosslinked polymer having the same chemical structure. In such swelling, the polymer can generally contain a solvent in an amount of 50% or more by weight of the polymer.

The monomer and / or oligomer (A) used in the present invention, whether organic or inorganic, may be any substance that can be polymerized by irradiation with energy rays to become a polymer. Any material such as polymerizability may be used. For example, those containing a vinyl group, a vinylidene group, an acryl group, a methacryl group, an acrylate ester, a methacrylate ester, etc., are preferably those having a high polymerization rate by irradiation with energy rays. For example, the monomers used in the present invention include ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, and 2-ethylhexyl (meth). )
Monofunctional monomers such as acrylate, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, n-vinylpyrrolidone, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyloxyethyl (meth) acrylate; Diethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 2,2′- Screw (4-
Bifunctional monomers such as (meth) acryloyloxypolyethyleneoxyphenyl) propane and 2,2′-bis (4- (meth) acryloyloxypolypropyleneoxyphenyl) propane, trimethylolpropane tri (meth) acrylate, trimethylolethane tri ( Meta)
Examples include trifunctional monomers such as acrylates, tetrafunctional monomers such as pentaerythritol tetra (meth) acrylate, and hexafunctional monomers such as dipentaerythritol hexaacrylate. Of course, it is also possible to use a mixture of these monomers.

The oligomer (A) used in the present invention is, for example, one that can be polymerized by irradiation with an energy ray and has a weight average molecular weight of 500 to 50,000. Methacrylate, acrylate or methacrylate of polyether resin, acrylate or methacrylate of polybutadiene resin,
A polyurethane resin having an acryl group or a methacryl group at a molecular terminal can be used. Of course, these oligomers can be used as a mixture, or can be used as a mixture with a monomer.

The oligomer (B) used in the present invention includes a polymer which is compatible with the above-mentioned monomer and / or oligomer (A) and which is produced by irradiating the monomer and / or oligomer (A) with energy rays. Any material may be used as long as it is incompatible and inert to energy rays, and has a weight average molecular weight of 200
Not less than 10,000. For example, the oligomer (B) used in the present invention includes liquid polyethylene glycol, monoester of polyethylene glycol, monoether of polyethylene glycol, polyethylene glycol sorbitan monoester, polyethylene glycol sorbitan diester, and polyethylene glycol sorbitan triester. , Polyester polyols, polyethylene glycolamine and the like. The oligomer (B) may have a single composition, a copolymer or a mixture.

The oligomer (B) can be prepared by the following methods: the method of producing the film, the type of the monomer and / or the oligomer (A),
It can be appropriately selected depending on the required viscosity of the polymerizable solution, the solubility of the polymer and other additives, the pore size and the pore shape required for the membrane, and the like.

When the polymerizable liquid is irradiated with energy rays and the oligomer (B) is removed, water having an advantage in terms of safety and health can be used when the oligomer (B) is removed. It is preferable that it is a property.

The polymer (C) used in the present invention is dissolved in the above-mentioned monomer and / or oligomer (A) or a homogeneous solution of the monomer and / or oligomer (A) and a solvent, and Any polymer may be used as long as it is incompatible with the polymer produced by irradiating the oligomer (A) with energy rays and is inactive to energy rays. For example, cellulose acetate, ethyl cellulose, nitrocellulose, hydroxymethyl cellulose, chitosan, polystyrene,
Polyvinyl chloride, polycarbonate, polysulfone, polyethersulfone, polyurethane, polyacrylonitrile, polyacrylate, polyacrylic acid, polymethyl methacrylate, polyacrylamide, polyethylene glycol, polyvinyl pyrrolidone, polyvinyl methyl ether, polyvinyl alcohol and These copolymers can be mentioned, and among them, chitosan, polyacrylic acid, polyacrylamide, polyethylene glycol, polyvinylpyrrolidone and polyvinyl alcohol are preferable.

The polymer (C) used in the present invention comprises:
It may be a single composition, a copolymer or a mixture. For the polymer (C), the difference in the method of producing the membrane, the type of the monomer and / or oligomer (A), the required viscosity of the polymerizable solution, the solubility of the polymer and other additives, the pore size required for the membrane And the shape of the pores. In addition, after irradiating the polymerizable liquid with energy rays, the polymer (C) is water-soluble because water having an advantage in terms of safety and health can be used when removing the polymer (C). Is preferred.

The solvent used in the present invention is a solvent capable of uniformly dissolving the monomer and / or oligomer (A) and the polymer (C), and
Alternatively, any material may be used as long as it can swell or dissolve the polymer formed by irradiating the oligomer (A) with energy rays. For example, when a polyurethane resin having an acrylic group at the molecular terminal is used as the oligomer (A), acetone, methyl ethyl ketone,
Ethyl acetate, dimethylformamide, n-methylpyrrolidone, dimethylacetamide, dimethylsulfoxide and the like can be suitably used.

Oligomer (B) and polymer (C)
Is preferably 0.1 to 4.0 parts by weight with respect to 1 part by weight of the monomer and / or the oligomer. 0.
If it is less than 1, the porosity of the film becomes low, and a sufficient amount of permeation cannot be obtained. If it is more than 4.0, the strength of the film becomes insufficient.

Monomer and / or oligomer (A)
For the selection of the viscosity of the polymerizable solution, in combination with the type of the oligomer (B), the polymer (C) or the solvent, the strength, flexibility, heat resistance, swelling resistance, pore size, It is determined by the degree of hydrophilicity and the like. For example, in order to obtain a porous polymer membrane having excellent heat resistance, a system containing only polyfunctional monomers and / or oligomers or a system containing a large amount of polyfunctional monomers and / or oligomers is selected. Conversely, when heat resistance is not required, a system containing only monofunctional monomers and / or oligomers or a system containing a large amount of monofunctional monomers and / or oligomers may be selected. When the content of the oligomer (B) or the polymer (C) is increased in order to increase the porosity of the film, it is desirable to select a high molecular weight oligomer (A) in order to maintain the film strength. Further, depending on the purpose of use, in order to obtain a hydrophilic or water-repellent film, it is possible to select a monomer or oligomer containing a hydroxyl group, a carboxyl group, a sulfonic acid group, an ammonium salt, or fluorine or a silyl group, and Monomers and oligomers can be mixed.

Polymerizable solution, that is, a mixture of monomer and / or oligomer (A) and oligomer (B), monomer and / or oligomer (A) and polymer (C)
If necessary, a polymerization initiator, a sensitizer, a thickener, a polymer, etc. may be added to the mixed solution of the above, the mixed solution of the monomer and / or oligomer (A), the solvent, and the polymer (C). . The viscosity of the polymerizable solution is not particularly limited and can be arbitrarily adjusted, but is preferably 100 cps to 1,000,000 cps at 25 ° C. The viscosity of the polymerizable solution affects the shape of the pores, and generally speaking, when the polymerizable solution has a low viscosity,
The shape of the pores is often given as gaps between the granular polymers adhered to each other, and conversely, when the viscosity is high, it is often given as gaps between the polymers deposited in a network. Also, the higher the viscosity, the smaller the pore size, and the lower the viscosity, the larger the pore size. The pore size also depends on the monomer and / or oligomer (A) and oligomer (B)
Alternatively, the effect of the mixing ratio with the polymer (C) is large, and when the ratio of the monomer and / or the oligomer (A) becomes higher than a certain level, the pore size tends to become smaller. Of course, these behaviors are based on monomers and / or oligomers (A)
And it can vary depending on the types of the oligomer (B) and the polymer (C), and can be appropriately determined depending on the combination of these materials and the intended performance of the membrane.

As the energy ray used in the present invention, an electron beam, γ-ray, X-ray, ultraviolet ray, visible light, or the like can be used. Above all, it is desirable to use ultraviolet rays because of the simplicity of equipment and handling. The intensity of the ultraviolet light to be irradiated is desirably 10 to 500 mW / cm ² , and the irradiation time is generally about 0.1 to 100 seconds. It is also possible to use flash light. When ultraviolet rays or visible rays are used as energy rays, a photopolymerization initiator can be included in the polymerizable solution for the purpose of increasing the polymerization rate. The polymerization rate can be further increased by irradiating ultraviolet rays in an inert gas atmosphere.

Electron beams are also preferable energy beams that can be used in the present invention. When an electron beam is used, it is not affected by the absorption of extraneous radiation such as a solvent, a non-solvent, and other additives, so that the range of choices thereof is widened and the film forming speed is improved.

As the ultraviolet polymerization initiator which can be mixed with the polymerizable solution of the present invention, p-tert-butyltrichloroacetophenone, 2,2'-diethoxyacetophenone,
2-hydroxy-2-methyl-1-phenylpropane
Acetophenones such as -1-one; benzophenone;
4,4'-bisdimethylaminobenzophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-
Ketones such as ethylthioxanthone and 2-isopropylthioxanthone; benzoin ethers such as benzoin, benzoin methyl ether, benzoin isopropyl ether and benzoin isobutyl ether; benzyl ketals such as benzyl dimethyl ketal and hydroxycyclohexyl phenyl ketone; .

In the present invention, the method of irradiating the polymerizable solution with an energy beam includes the steps of: dipping, roll coating, doctor blade, spin coating on a support;
A method of irradiating in a state of forming a thin film by coating by a coating method, a spraying method, or the like, and a method of irradiating in a state of being extruded from a nozzle into a hollow fiber or a curtain and falling in the air can be used. As a support,
Metal, ceramics, glass, plastic, cloth, nonwoven fabric, paper, microfiltration membrane, porous hollow fiber, and the like can be used. When a belt-shaped support or a porous hollow fiber is used as the support, a thin film can be continuously formed. The membrane may eventually peel off from the support,
When the support is porous, the support can be used as it is.

The obtained porous polymer membrane is obtained by washing the oligomer (B), polymer (C),
Unreacted monomers and / or oligomers (A), ultraviolet polymerization initiators, and other additives are removed. Further, the obtained porous polymer membrane can be subjected to a heat treatment as needed to adjust the pore diameter and increase the heat resistance and the dimensional stability.

[0031]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention.

Example 1 (Preparation of Polymerizable Solution) A urethane acrylate oligomer having a molecular weight of 800 and having three acrylic groups on average per molecule (Dainippon Ink Co., Ltd.)
"Unidick S9-414" manufactured by Chemical Industry Co., Ltd.)
60 parts, tripropylene glycol diacrylate 40
Part, Irgacure-184 (1-hydroxycyclohexyl phenyl ketone, UV polymerization initiator,
2 parts, polyethylene glycol monolaurate
(Polyethylene glycol part manufactured by Tokyo Chemical Industry Co., Ltd.
And a polymerization degree of 10 minutes) to obtain a polymerizable solution 1 having a viscosity of 500 cps at 23 ° C. (Preparation of Porous Polymer Film) The polymerizable solution 1 was applied on a glass plate by a film applicator so as to have a thickness of 200 μm. The intensity at 360 nm is 100 mW /
Irradiated with ultraviolet light of cm ² for 10 seconds. It was observed that the coating film that was transparent before irradiation changed to milky white after irradiation. The resulting milky white film was peeled off from the glass plate and washed with water for 30 minutes to wash out polyethylene glycol monolaurate. The membrane after washing was sufficiently dried under reduced pressure to obtain a porous polymer membrane. According to the electron microscope, polymer particles adhered to each other and pores provided as gaps were observed. The pore diameter and pore shape were almost the same at the surface of the porous polymer membrane and at any position in the membrane cross section. When the porous polymer film cut into a 1 cm square was measured with a mercury porosimeter (manufactured by Carlo Elba), the peak of the pore size distribution was 0.8 μm, and the volume porosity was 51.5%.

(Evaluation of Filtration Performance) Using an ultrafiltration apparatus SM-165-26 manufactured by Sartorius Co., Ltd., 2
When water at 5 ° C. was permeated, the flux was 14,000.
1 / m ² · hr (pressure 3 kg / cm ² ). Pressure 3
When the filtration test at Kg / cm ² was continued at room temperature for 24 hours, the rate of reduction of the flux was hardly reduced to 2%. After heat treatment of this porous polymer membrane in water at 80 ° C. for 1 hour, the flux of water at 70 ° C. was 19000.
1 / m ² · hr, and the reduction rate of the flux when the filtration test was continued at 70 ° C. for 24 hours at a pressure of 3 kg / cm ² was 3%. On the other hand, when this porous polymer film was immersed in a solvent of an acrylic polymer such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, etc., it swelled and became transparent but did not dissolve.

Example 2 (Preparation of Hollow Fiber Membrane) Diameter 6 mm, slit width 0.4 m
m, using a circular nozzle having a core material injection hole diameter of 2 mm, while injecting water as a core material, extruding the polymerizable solution 1 into the air at 80 ml / min (discharge linear velocity: 19 cm / sec). A range of 60 cm was irradiated with ultraviolet rays having a wavelength of 360 nm by a 6 KW metal halide lamp using a condenser mirror. The cured hollow fiber was dropped on a table 150 cm below the nozzle. The obtained wet hollow fiber had an outer diameter of 0.8 mm and an inner diameter of 0.4 mm, and was milky white. The production rate of the hollow fiber is 350 cm / sec, and the draft ratio is calculated to be 18. The hollow fiber was washed with water and ethanol, and sufficiently dried under reduced pressure to obtain a white hollow fiber membrane having no gloss on the surface.

(Characteristics of Hollow Fiber Membrane) This hollow fiber membrane has an outer diameter of 0.75 mm and an inner diameter of 0.4 mm. According to an electron microscope, polymer particles adhered to each other, Was observed. The pore diameter and pore shape were almost the same at any position on the inner surface, outer surface, and cross section of the hollow fiber membrane. When 0.3 g of the hollow fiber membrane cut into a length of 1 cm was measured with a mercury porosimeter (manufactured by Carlo Elba), the peak of the pore size distribution was 0.8 μm, and the volume porosity was 50.4%.

Example 3 (Preparation of Porous Membrane Backed by Porous Support) Using a bar coater, a polyester nonwoven fabric MF-180 manufactured by Japan Vilene Co., Ltd. installed on a glass plate was polymerized. Solution 1 is applied, and 360n is applied by a metal halide lamp.
Ultraviolet light having an intensity of 100 mW / cm ² was applied for 10 seconds. The resulting milky white film was sufficiently washed with water and ethanol to obtain a porous film lined with a nonwoven fabric. The permeation amount of the applied polymerizable solution into the nonwoven fabric was appropriate, and the seepage of the polymerizable solution on the back side of the nonwoven fabric was slight. The obtained porous membrane was sufficiently integrated with the nonwoven fabric, and it was impossible to peel them off.

According to electron microscopic observation of the surface of the obtained polymer film on the side on which the polymerizable solution was applied, polymer particles adhered to each other and pores provided as gaps were observed. When the porous polymer membrane cut into a 1 cm square was measured with a mercury porosimeter (manufactured by Carlo Elba), the peak of the pore size distribution was 0.8 μm, and the volume porosity was 5 μm.
1.8%.

Example 4 (Preparation of Polymerizable Solution) An epoxy acrylate oligomer having a weight-average molecular weight of 1,000 and having two acrylic groups on average in one molecule (Na)
"Epoxy acrylate DA" manufactured by Gase Kasei Kogyo Co., Ltd.
-931 ") 80 parts, phenoxyethyl acrylate 2
0 parts, 4 parts Irgacure 184, Po Li ethylene glycol sorbitan monolaurate (Tokyo Kasei Kogyo shares Association
(“Tween # 20” manufactured by KK Corporation) was mixed to obtain a polymerizable solution 2 having a viscosity of 2000 cps at 23 ° C.

(Preparation of Hollow Fiber Membrane) Using a circular nozzle having a diameter of 2 mm, a slit width of 0.2 mm, and a core material injection hole diameter of 0.8 mm, 68 ml of the polymerizable solution 2 was injected while nitrogen gas was injected as a core material. / Min (discharge linear velocity 100 cm / sec) into a nitrogen atmosphere, and a range of 10 to 80 cm below the nozzle is set to a wavelength of 360 nm by a 6 KW metal halide lamp.
Was irradiated using a condenser mirror. The cured hollow fiber was dropped on a table 250 cm below the nozzle. The obtained wet hollow fiber had an outer diameter of 1.4 mm and an inner diameter of 1.0.
mm. At this time, the generation rate of the hollow fiber was 144 cm.
/ S, from which the draft ratio is calculated to be 1.44. The hollow fiber was washed with water and ethanol, and sufficiently dried under reduced pressure to obtain a white hollow fiber membrane having no gloss on the surface.

This hollow fiber membrane has an outer diameter of 1.3 mm and an inner diameter of 1.
According to electron microscopic observation, polymer particles adhered to each other and pores provided as gaps were observed. The pore diameter and pore shape were almost the same at any position on the inner surface, outer surface, and cross section of the hollow fiber membrane. The peak of the pore size distribution measured in the same manner as in Example 1 was 0.6 μm, and the volume porosity was 49.4%.

Example 5 (Preparation of Porous Membrane Backed by Porous Support) A qualitative filter paper No. No. manufactured by Toyo Filter Paper Co., Ltd. was installed on a glass plate with a bar coater. 2 was coated with a solution 2 made of polymer, and the intensity at 360 nm was 100 mW / cm by a metal halide lamp.
² was irradiated for 10 seconds. The resulting milky white film was sufficiently washed with water and ethanol to obtain a porous film lined with filter paper. The permeation amount of the applied polymerizable solution into the filter paper was appropriate, and the seepage of the polymerizable solution on the back side of the filter paper was slight. The obtained porous membrane was sufficiently integrated with the filter paper, and it was impossible to peel them off.

According to electron microscopic observation of the surface of the obtained polymer film on the side where the polymerizable solution was applied, polymer particles adhered to each other and pores provided as gaps were observed. When the porous polymer membrane cut into a 1 cm square was measured with a mercury porosimeter (manufactured by Carlo Elba), the peak of the pore size distribution was 0.6 μm, and the volume porosity was 5 μm.
2.5%.

Example 6 (Preparation of Polymerizable Solution) A urethane acrylate oligomer having a weight average molecular weight of 3000 and having three acrylic groups on average in one molecule (large
"Unidick V-4" manufactured by Nippon Ink Chemical Industry Co., Ltd.
263 "), 80 parts of neopentyl glycol diacrylate, 4 parts of Irgacure 651 (benzyldimethyl ketal, Shibaishi polymerization initiator, Ciba-Geigy).
Parts, Kurapole P-510 (Kuraray Co., Ltd. polyester oligomer) 160 parts and acetone 20 parts,
A polymerizable solution 3 having a viscosity of 2000 cps at 3 ° C. was obtained.

(Preparation of Porous Polymer Membrane) A polymerizable solution 3 was applied on a glass plate by a film applicator to a thickness of 2
It was applied so as to have a thickness of 00 μm. The glass plate was left under a nitrogen stream for 2 minutes to volatilize part of acetone, and then 360 nm was irradiated with a metal halide lamp.
UV light having an intensity of 100 mW / cm ² was irradiated for 10 seconds. It was observed that the coating film that was transparent before irradiation changed to milky white after irradiation. The resulting milky white film was peeled off from the glass plate and washed with acetone to wash out Clapol P-510. The membrane after washing was sufficiently dried under reduced pressure to obtain a porous polymer membrane.
According to the electron microscope, the polymer particles adhered to each other,
The pores provided as the gaps were observed. The pore diameter was about 0.02 μm on the surface of the porous polymer membrane, and about 1 μm on the glass plate side. Mercury porosimeter (manufactured by Carlo Elba) using a porous polymer membrane cut into 1 cm square
As a result, the peak of the pore size distribution was 0.8 μm,
The volume porosity was 45.2%.

(Evaluation of Filtration Performance) A filtration experiment of a 0.3% aqueous solution of polyethylene glycol having a molecular weight of 50,000 was conducted using an ultrafiltration apparatus SM-165-26 manufactured by Sartorius. The FLUX of the aqueous polyethylene glycol solution at a filtration temperature of 25 ° C. and a filtration pressure of 3 kg / cm ² is 12
0 l / m ² · hr, the rejection of polyethylene glycol was 80%.

Example 7 (Preparation of Polymerizable Solution) Urethane acrylate oligomer having a molecular weight of 800 and having an average of three acrylic groups per molecule (Dainippon Ink Co., Ltd.)
"Unidick S9-414" manufactured by Chemical Industry Co., Ltd.)
60 parts, tripropylene glycol diacrylate 40
Parts, 2 parts Irgacure 184, weight average molecular weight 10
000 of polyvinylpyrrolidone and 150 parts of n-methylpyrrolidone were mixed, and the viscosity at 23 ° C was 300.
A polymerizable solution 4 of 0 cps was obtained.

(Preparation of Porous Polymer Film) The polymerizable solution 4 was applied on a glass plate by a film applicator to a thickness of 2
It was applied so as to have a thickness of 00 μm. Ultraviolet rays having an intensity of 360 nm and an intensity of 100 mW / cm ² were irradiated for 10 seconds by a metal halide lamp. It was observed that the coating film that was transparent before irradiation changed to milky white after irradiation. The obtained milky white film was peeled off from the glass plate and washed with water for 30 minutes to wash out polyvinylpyrrolidone and n-methylpyrrolidone. The membrane after washing was sufficiently dried under reduced pressure to obtain a porous polymer membrane. According to the electron microscope, pores provided as gaps of the polymer precipitated in a three-dimensional network were observed. The pore diameter and pore shape were almost the same at the surface of the porous polymer membrane and at any position in the membrane cross section. When the porous polymer membrane cut into a 1 cm square was measured with a mercury porosimeter (manufactured by Carlo Elba), the peak of the pore size distribution was 0.4 μm.
m, the volume porosity was 49.5%.

(Evaluation of Filtration Performance) Using an ultrafiltration apparatus SM-165-26 manufactured by Sartorius Co., Ltd., 2
When water at 5 ° C. was permeated, the flux was 6000 l.
/ M ² · hr (pressure 3 kg / cm ² ). Pressure 3K
When the filtration test at g / cm ² was continued at room temperature for 24 hours, the flux reduction rate was hardly reduced to 2%. After heat treatment of this porous polymer membrane in water at 80 ° C. for 1 hour, the flux of water at 70 ° C. was 12000.
1 / m ² · hr, and the reduction rate of the flux when the filtration test was continued at 70 ° C. for 24 hours at a pressure of 3 kg / cm ² was 3%. On the other hand, when this porous polymer film was immersed in a solvent of an acrylic polymer such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, etc., it swelled and became transparent but did not dissolve.

Example 8 (Preparation of Hollow Fiber Membrane) A hollow fiber was spun in the same manner as in Example 2 except that polymerizable solution 4 was used and nitrogen gas was used as a core agent. The obtained wet hollow fiber has an outer diameter of 0.8 mm,
It had an inner diameter of 0.4 mm and was milky white. The production rate of the hollow fiber is 350 cm / sec, and the draft ratio is calculated to be 18. The hollow fiber was washed with water and ethanol, and sufficiently dried under reduced pressure to obtain a white hollow fiber membrane having no gloss on the surface.

(Characteristics of Hollow Fiber Membrane) The hollow fiber membrane has an outer diameter of 0.74 mm and an inner diameter of 0.4 mm, and according to an electron microscope, pores provided as gaps of a polymer precipitated in a three-dimensional network. Was observed. The pore diameter and pore shape were almost the same at any position on the inner surface, outer surface, and cross section of the hollow fiber membrane. When 0.3 g of the hollow fiber membrane cut into a length of 1 cm was measured with a mercury porosimeter (manufactured by Carlo Elba), the peak of the pore size distribution was 0.6.
μm, the volume porosity was 49.4%.

Example 9 (Preparation of Polymerizable Solution) An epoxy acrylate oligomer having a weight-average molecular weight of 1,000 and having two acrylic groups on average in one molecule (Na)
"Epoxy acrylate DA" manufactured by Gase Kasei Kogyo Co., Ltd.
-931 ") 80 parts, phenoxyethyl acrylate 2
0 parts, 2 parts of Irgacure 184, 50 parts of cellulose acetate
And 150 parts of dimethylacetamide were mixed to obtain a polymerizable solution 5 having a viscosity of 4000 cps at 23 ° C.

(Preparation of Porous Membrane Backed by Porous Support) Qualitative filter paper N manufactured by Toyo Roshi Kaisha Co., Ltd. with a bar coater
o. 2 was coated with a solution 5 made of a polymer, and irradiated with ultraviolet light having a wavelength of 360 nm and an intensity of 100 mW / cm ² for 10 seconds using a metal halide lamp. The resulting milky white film was sufficiently washed with acetone and ethanol to obtain a porous film lined with filter paper. The permeation amount of the applied polymerizable solution into the filter paper was appropriate, and the seepage of the polymerizable solution on the back side of the filter paper was slight. The obtained porous membrane was sufficiently integrated with the filter paper, and it was impossible to peel them off.

According to electron microscopic observation of the surface of the obtained polymer film on the side where the polymerizable solution was applied, pores provided as gaps of the polymer precipitated in a three-dimensional network were observed. When the porous polymer membrane cut into 1 cm square was measured with a mercury porosimeter (manufactured by Carlo Elba), the peak of the pore size distribution was 0.15 μm, and the volume porosity was 32.0.
%Met.

[Example 10] (Preparation of polymerizable solution) 2,2'-bis (4-acryloyloxypolyethyleneoxyphenyl) propane (manufactured by Daiichi Kogyo Seiyaku Co., Ltd. )
"New Frontier BPE-4") 50 parts, neopentyl glycol diacrylate 20 parts, n-vinyl pyrrolidone 30 parts, Irgacure 184 2 parts, polyacrylamide (Aldrich Chemical Company, Inc.)
Corporation (Aldrich Chemical Company, Inc.)
And 100 parts of an average molecular weight of 1500).
A polymerizable solution 6 having a viscosity of 4000 cps at 3 ° C. was obtained.

(Preparation of Porous Membrane Backed by Porous Support) Qualitative filter paper N manufactured by Toyo Roshi Kaisha Co., Ltd. using a bar coater.
o. 2 was coated with a solution 6 made of a polymer, and irradiated with ultraviolet rays having a wavelength of 360 nm and an intensity of 100 mW / cm ² for 10 seconds by a metal halide lamp. The resulting milky white film was sufficiently washed with acetone and ethanol to obtain a porous film lined with filter paper. The permeation amount of the applied polymerizable solution into the filter paper was appropriate, and the seepage of the polymerizable solution on the back side of the filter paper was slight. The obtained porous membrane was sufficiently integrated with the filter paper, and it was impossible to peel them off.

According to electron microscopic observation of the surface of the obtained polymer film on the side on which the polymerizable solution was applied, pores provided as gaps of the polymer precipitated in a three-dimensional network were observed. When the porous polymer film cut into a 1 cm square was measured with a mercury porosimeter (manufactured by Carlo Elba), the peak of the pore size distribution was 0.10 μm, and the volume porosity was 36.5.
%Met.

Comparative Example 1 In this comparative example, it is shown that the porous film produced by the wet method is inferior in creep resistance and heat resistance.

(Preparation of Hollow Fiber Membrane) A dope prepared by dissolving 30 parts of polysulfone (P-1800NT, manufactured by Amoco) in 70 parts of n-methylpyrrolidone was used. Using a 0.8 mm annular nozzle, extruding into water at 0.75 ml / min (discharge linear velocity 1.1 cm / sec) while injecting water as a core agent, and 1.25 cm / sec (draft After staying in water for about 10 minutes while taking over at a ratio of 1.15), take it out,
After washing with water and drying, a hollow fiber membrane having an outer diameter of 1.8 mm and an inner diameter of 1.45 mm was obtained.

(Characteristics of Hollow Fiber Membrane) When this hollow fiber membrane was observed with an electron microscope, a network-like polymer and pores having a cross section close to a circle were observed. The shape and diameter of the pores were almost the same on the inner surface, outer surface, and the cross section of the hollow fiber membrane. The peak of the pore size distribution measured in the same manner as in Example 1 was 2.5 μm, and the volume porosity was 4
9.1%.

[0060] flux measured in the same manner as in Example 1 was 100000L / h · m ^2, the filtration test 2
The rate of decrease in the flux after continuing for 4 hours was 33%. The flux of the 70 ° C. water of the membrane obtained by heat-treating the hollow fiber membrane in 80 ° C. water for 1 hour is 70,000 l / min · m ² , and the flux when the filtration test at 70 ° C. is continued for 24 hours. Was 5%.

The pressure resistance of the hollow fiber membrane in the same manner as in Example 1 was 10.1 kg / cm ² . When this film was immersed in dimethylformamide, methylene chloride, acetone or the like, it was completely dissolved.

[Comparative Example 2] In this comparative example,
The use of a non-solvent as recommended in JP-A-34329 and JP-B-63-65220 indicates that it is difficult to produce a hollow fiber membrane.

(Preparation of Polymerizable Solution) A urethane acrylate oligomer having a molecular weight of 800 and having an average of three acrylic groups per molecule having a molecular weight of 800, 60 parts of tripropylene glycol diacrylate, Irgacure-184 (1-hydroxycyclohexylphenyl) Ketone, UV polymerization initiator, 2 parts by Ciba-Geigy), methyl caprate 16
0 parts were mixed to obtain a polymerizable solution 6 having a viscosity of 20 cps at 23 ° C.

(Preparation of Hollow Fiber Membrane) An attempt was made to spin a hollow fiber in the same manner as in Example 2 except that the polymerizable solution 6 was used. However, the fiber diameter distribution was extremely beaded.

[Comparative Example 3] In this comparative example,
The use of a non-solvent as recommended in JP-A-34329 and JP-B-63-65220 indicates that it is difficult to form a porous membrane backed by a porous support.

(Preparation of Polymerizable Solution)
60 parts of an epoxy acrylate oligomer having an average of two acrylic groups in the molecule, 60 parts of tripropylene glycol diacrylate, 2 parts of Irgacure-184 (1-hydroxycyclohexyl phenyl ketone, an ultraviolet polymerization initiator, manufactured by Ciba Geigy) And 160 parts of butanol were mixed to obtain a polymerizable solution 7 having a viscosity of 19 cps at 23 ° C.

(Preparation of Porous Membrane Backed by Porous Support) On a polyester nonwoven fabric MF-180 manufactured by Japan Vilene Co., Ltd., which was installed on a glass plate with a bar coater,
When the polymer solution 7 was applied, almost all of the solution flowed on the glass plate, and it was impossible to form a porous film lined with nonwoven cloth.

Comparative Example 4 This comparative example shows that a porous polymer film cannot be obtained unless the oligomer (B) or the polymer (C) is added to the polymerizable solution.

(Preparation of Polymerizable Solution) A urethane acrylate oligomer having a molecular weight of 800 and having an average of three acrylic groups per molecule, 60 parts, tripropylene glycol diacrylate 40 parts, Irgacure 184 (1-hydroxycyclohexyl phenyl ketone) , UV polymerization initiator, Ciba-Geigy) (2 parts) to obtain a polymerization solution 8 having a viscosity of 1200 cps at 23 ° C.

(Preparation of Polymer Film) The polymerizable solution 8 was coated on a glass plate with a film applicator to a thickness of 200 μm.
m. A metal halide lamp emits 10 ultraviolet rays having an intensity of 360 nm and an intensity of 100 mW / cm ^2.
Irradiated for seconds. The polymer film was obtained by peeling the obtained colorless and transparent film from the glass plate. According to the electron microscope, no pore was observed on the surface and cross section of the polymer film.

Comparative Example 5 This comparative example shows that a porous polymer film cannot be obtained unless the polymer (C) is removed after irradiating the polymerizable solution with energy rays.

(Preparation of Polymer Film) The polymerizable solution 4 of Example 7 was applied on a glass plate by a film applicator so as to have a thickness of 200 μm. Ultraviolet rays having an intensity of 360 nm and an intensity of 100 mW / cm ² were irradiated for 10 seconds by a metal halide lamp. The resulting translucent film was peeled from the glass plate to obtain a polymer film. According to the electron microscope, no pore was observed on the surface and cross section of the polymer film.

[0073]

As described above, the porous polymer film obtained by the production method of the present invention has a crosslinked structure, and therefore has the characteristics of being excellent in strength, creep resistance, heat resistance and chemical resistance. Further, since a polymerizable solution having a high viscosity of 100 cps or more can be obtained, a porous membrane backed by a porous support such as a hollow fiber-shaped porous membrane, a nonwoven fabric, a cloth, paper, or a microfiltration membrane can be easily produced. It has the feature of.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08J 9/26-9/28

Claims (11)

(57) [Claims] 1. A monomer and / or oligomer (A) which can be polymerized by irradiation with an energy ray, is compatible with the monomer and / or oligomer (A), and an energy ray is applied to the monomer and / or oligomer (A). After irradiating the uniform polymerizable liquid mixed with the oligomer (B) which is not compatible with the polymer produced by the irradiation and inert to the energy beam with the energy beam, the oligomer (B) is removed. A method for producing a porous polymer membrane. 2. The polymerizable liquid has a viscosity of 10 at 25 ° C.
2. The method according to claim 1, wherein the speed is not less than 0 cps and not more than 1,000,000 cps.
The manufacturing method as described. 3. The oligomer (B) having a weight average molecular weight of 2
The production method according to claim 1, wherein the number is from 00 to 10,000. 4. The process according to claim 1, wherein the oligomer (B) is water-soluble. 5. The oligomer (B) is a liquid polyethylene glycol, a polyethylene glycol monoester, a polyethylene glycol monoether, a polyethylene glycol sorbitan monoester, a polyethylene glycol sorbitan diester, a polyethylene glycol sorbitan triester, a polyester polyol. 4. The method according to claim 1, wherein the liquid is at least one liquid selected from the group consisting of polyethylene glycol amines. 6. A monomer and / or oligomer (A) polymerizable by irradiation with an energy ray and a homogeneous solution of the monomer and / or oligomer (A) or the monomer and / or oligomer (A) and a solvent. Uniform polymerization by dissolving and mixing a polymer (C) which is incompatible with a polymer formed by irradiating the monomer and / or oligomer (A) with energy rays and which is inactive to energy rays A method for producing a porous polymer film, comprising irradiating an ionic liquid with an energy beam and then removing the polymer (C). 7. The polymerizable liquid has a viscosity of 10 at 25 ° C.
7. The pressure is not less than 0 cps and not more than 1,000,000 cps.
The manufacturing method as described. 8. The polymer (C) is cellulose acetate, ethyl cellulose, nitrocellulose, hydroxymethyl cellulose, chitosan, polystyrene, polyvinyl chloride,
Polycarbonate, polysulfone, polyethersulfone, polyurethane, polyacrylonitrile, polyacrylate, polyacrylic acid, polymethyl methacrylate, polyacrylamide, polyethylene glycol,
The method according to claim 6, wherein the polymer is at least one polymer selected from the group consisting of polyvinylpyrrolidone, polyvinyl methyl ether and polyvinyl alcohol. 9. The polymer (C) is water-soluble.
Or the manufacturing method of 7. 10. The polymer according to claim 6, wherein the polymer (C) is at least one polymer selected from the group consisting of chitosan, polyacrylic acid, polyacrylamide, polyethylene glycol, polyvinylpyrrolidone, and polyvinyl alcohol. Production method. 11. The method according to claim 1, wherein an ultraviolet ray or an electron beam is used as the energy ray.