WO1999046034A1 - Membrane composite a fibres creuses et son procede de fabrication - Google Patents
Membrane composite a fibres creuses et son procede de fabrication Download PDFInfo
- Publication number
- WO1999046034A1 WO1999046034A1 PCT/JP1999/001245 JP9901245W WO9946034A1 WO 1999046034 A1 WO1999046034 A1 WO 1999046034A1 JP 9901245 W JP9901245 W JP 9901245W WO 9946034 A1 WO9946034 A1 WO 9946034A1
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- WO
- WIPO (PCT)
- Prior art keywords
- hollow fiber
- layer
- fiber membrane
- composite
- composite hollow
- Prior art date
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- 239000012528 membrane Substances 0.000 title claims abstract description 183
- 239000012510 hollow fiber Substances 0.000 title claims abstract description 169
- 239000002131 composite material Substances 0.000 title claims abstract description 110
- 238000004519 manufacturing process Methods 0.000 title claims description 15
- 210000001724 microfibril Anatomy 0.000 claims abstract description 72
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 69
- 239000010410 layer Substances 0.000 claims description 270
- 229920000642 polymer Polymers 0.000 claims description 55
- 239000013078 crystal Substances 0.000 claims description 50
- 230000035699 permeability Effects 0.000 claims description 28
- 239000011148 porous material Substances 0.000 claims description 26
- 239000000835 fiber Substances 0.000 claims description 22
- 238000002425 crystallisation Methods 0.000 claims description 14
- 230000008025 crystallization Effects 0.000 claims description 14
- 239000011347 resin Substances 0.000 claims description 12
- 229920005989 resin Polymers 0.000 claims description 12
- 229920001477 hydrophilic polymer Polymers 0.000 claims description 8
- 239000011247 coating layer Substances 0.000 claims description 4
- 238000001914 filtration Methods 0.000 abstract description 29
- 241000446313 Lamella Species 0.000 abstract description 7
- 230000005540 biological transmission Effects 0.000 abstract description 2
- 239000000428 dust Substances 0.000 abstract description 2
- 239000008235 industrial water Substances 0.000 abstract description 2
- 238000005194 fractionation Methods 0.000 description 21
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 14
- 229920001903 high density polyethylene Polymers 0.000 description 12
- 238000000034 method Methods 0.000 description 12
- 239000002245 particle Substances 0.000 description 12
- 238000009987 spinning Methods 0.000 description 12
- 239000004700 high-density polyethylene Substances 0.000 description 11
- 229920001480 hydrophilic copolymer Polymers 0.000 description 11
- 238000000137 annealing Methods 0.000 description 10
- 230000007423 decrease Effects 0.000 description 10
- -1 polyethylene Polymers 0.000 description 10
- 239000002904 solvent Substances 0.000 description 10
- 229920001577 copolymer Polymers 0.000 description 8
- 229920000219 Ethylene vinyl alcohol Polymers 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 230000004907 flux Effects 0.000 description 7
- 230000001965 increasing effect Effects 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- 238000000926 separation method Methods 0.000 description 7
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 6
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 239000012046 mixed solvent Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 239000004698 Polyethylene Substances 0.000 description 5
- 238000009826 distribution Methods 0.000 description 5
- 239000012982 microporous membrane Substances 0.000 description 5
- 239000000178 monomer Substances 0.000 description 5
- 229920000573 polyethylene Polymers 0.000 description 5
- 238000000576 coating method Methods 0.000 description 4
- 238000007654 immersion Methods 0.000 description 4
- 239000000155 melt Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 3
- IMROMDMJAWUWLK-UHFFFAOYSA-N Ethenol Chemical compound OC=C IMROMDMJAWUWLK-UHFFFAOYSA-N 0.000 description 3
- 239000005977 Ethylene Substances 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 239000004743 Polypropylene Substances 0.000 description 3
- 239000004793 Polystyrene Substances 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 238000002835 absorbance Methods 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000010622 cold drawing Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 238000011049 filling Methods 0.000 description 3
- 238000009998 heat setting Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- 229920001155 polypropylene Polymers 0.000 description 3
- 229920002223 polystyrene Polymers 0.000 description 3
- 238000004382 potting Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000002356 single layer Substances 0.000 description 3
- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 description 2
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- 230000001580 bacterial effect Effects 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000007380 fibre production Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 239000004816 latex Substances 0.000 description 2
- 229920000126 latex Polymers 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000012466 permeate Substances 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 239000008399 tap water Substances 0.000 description 2
- 235000020679 tap water Nutrition 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- YHQXBTXEYZIYOV-UHFFFAOYSA-N 3-methylbut-1-ene Chemical compound CC(C)C=C YHQXBTXEYZIYOV-UHFFFAOYSA-N 0.000 description 1
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- GAWIXWVDTYZWAW-UHFFFAOYSA-N C[CH]O Chemical group C[CH]O GAWIXWVDTYZWAW-UHFFFAOYSA-N 0.000 description 1
- 101000680262 Homo sapiens Transmembrane protein 60 Proteins 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- WHNWPMSKXPGLAX-UHFFFAOYSA-N N-Vinyl-2-pyrrolidone Chemical compound C=CN1CCCC1=O WHNWPMSKXPGLAX-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 102100022076 Transmembrane protein 60 Human genes 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 229920001400 block copolymer Polymers 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000003028 elevating effect Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 229920000578 graft copolymer Polymers 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002074 melt spinning Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000013081 microcrystal Substances 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 229920000306 polymethylpentene Polymers 0.000 description 1
- 239000011116 polymethylpentene Substances 0.000 description 1
- 239000011118 polyvinyl acetate Substances 0.000 description 1
- 229920002689 polyvinyl acetate Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 1
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 1
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 229920005604 random copolymer Polymers 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
- B01D69/1216—Three or more layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0081—After-treatment of organic or inorganic membranes
- B01D67/0088—Physical treatment with compounds, e.g. swelling, coating or impregnation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0023—Organic membrane manufacture by inducing porosity into non porous precursor membranes
- B01D67/0025—Organic membrane manufacture by inducing porosity into non porous precursor membranes by mechanical treatment, e.g. pore-stretching
- B01D67/0027—Organic membrane manufacture by inducing porosity into non porous precursor membranes by mechanical treatment, e.g. pore-stretching by stretching
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/08—Hollow fibre membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/26—Polyalkenes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/26—Polyalkenes
- B01D71/261—Polyethylene
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/26—Polyalkenes
- B01D71/262—Polypropylene
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/24—Formation of filaments, threads, or the like with a hollow structure; Spinnerette packs therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/02—Details relating to pores or porosity of the membranes
- B01D2325/022—Asymmetric membranes
- B01D2325/023—Dense layer within the membrane
Definitions
- the present invention relates to a hollow fiber membrane that can be used as a filter for water treatment of household water purifiers, industrial water filtration modules, and the like, and a filter for dust filtration in the air.
- This application is based on a patent application to Japan (Japanese Patent Application No. 10-63648), the contents of which are incorporated herein by reference. Background art
- Microporous membranes are widely used for water purification or wastewater treatment or air filters.
- Japanese Patent Application Laid-Open Publication No. 57-66114 discloses microfibrils oriented in the long axis direction of hollow fiber membranes and lamellas oriented in the long axis direction of hollow fiber membranes.
- the figure shows a polyethylene microporous hollow fiber membrane in which a plurality of slit-like micropores formed by the nodules of a stacked crystal (stack dramella) are formed.
- the polyethylene microporous hollow fiber membrane has a high water permeability, it has insufficient fractionation characteristics.
- Japanese Patent Publication (B2) Hei 3-753039 discloses a microporous membrane made of hydrophilized polyethylene in which a microporous membrane is coated with an ethylene-vinyl alcohol copolymer. It is shown.
- this microporous membrane cannot improve the fractionation characteristics while maintaining a high water permeability.
- Japanese Patent Publication (B2) No. 62-44046 and Japanese Patent Publication (A) Japanese Patent Publication No. 62-269706 show slit-shaped fine particles having different sizes.
- a composite hollow fiber membrane obtained by laminating a plurality of membranes each having a hole is shown.
- the water permeability of these composite hollow fiber membranes is insufficient for practical use.
- International Publication W095Z1919 includes a dense layer with a small pore size for the separation function and a support layer with a large pore size for the reinforcement function.
- a composite microporous membrane made of polyolefin comprising: More specifically, 1 a dense layer outside the hollow fiber membrane, a two-layer structure membrane with a support layer inside, 2 a dense layer inside the hollow fiber membrane, a two-layer structure membrane with a support layer outside, (3) A three-layer structure membrane in which a support layer is disposed on the innermost and outermost layers of the hollow fiber membrane and a dense layer is disposed in the middle is disclosed.
- the filtration life can be made longer than in the two-layer structure membrane (1), but the separation accuracy (for fractionated particles) In terms of rejection).
- the separation accuracy for fractionated particles
- the molten polymer inside the fiber is cooled more slowly than the molten polymer outside the fiber. Further, heat is not easily radiated in the hollow portion of the hollow fiber, and the inside of the fiber is likely to be insufficiently cooled.
- the inner molten polymer is likely to crystallize in a state where the polymer molecular chains are crystallized without receiving sufficient tensile stress (stress proportional to viscosity) and the degree of orientational order in the fiber axis direction is disturbed.
- stress proportional to viscosity stress proportional to viscosity
- the fine pore size (especially the fibril interval) after drawing becomes non-uniform in the thickness direction. It is considered that the accuracy is reduced.
- the membrane has a three-layer structure in which the innermost layer and outermost layer of the hollow fiber membrane are provided with a support layer and a dense layer in the middle, the composite unstretched hollow fiber is not spun into a dense layer during the spinning process.
- the stretching layer portion is more likely to be delayed in cooling than the outer layer portion, and is easily crystallized in a state where the degree of crystal orientation is disordered in the fiber axis direction.
- the fine pore size (especially the fibril interval) after the stretching tends to be non-uniform in the thickness direction, and the degrading characteristics are likely to be lowered.
- the present invention has been made to solve the above-mentioned problems, and is a hollow fiber suitable for water filtration and air filtration, which hardly causes clogging, has a long filtration life, exhibits both high permeation flow rate and high fractionation characteristics. It is intended for a film and a method for producing the film.
- the present inventors have conducted intensive studies and found that the filtration life and the separation accuracy are such that the porosity of the entire membrane is 75 vol% or more, and fine pores of nearly uniform size are formed in the support layer and the dense layer. It has been found that a hollow fiber membrane having three or more layers with a dense layer arranged in the middle is suitable for this improvement.
- the composite hollow fiber membrane of the present invention is a composite hollow fiber membrane in which three or more layers having a three-dimensional network structure having a plurality of micropores formed by microfibrils combined with the stack dramella are laminated.
- the hollow fiber membrane which is an intermediate layer located between the outermost layer and the innermost layer, is thinner than the outermost layer and the innermost layer, and has an average pore diameter of the average pores of the outermost layer and the innermost layer. It has a dense layer smaller than the pore size.
- the porosity of the entire composite hollow fiber membrane is 75 vol% or more.
- the isothermal crystallization time of the resin in the outermost layer and the innermost layer s and the isothermal crystallization time P of the resin in the dense layer satisfy the following formula.
- the outermost layer and the innermost layer preferably have an average microfibril length of 0.5 to 10 wm and an average microfibril interval of 0.1 to 0.6 zm.
- the dense layer preferably has an average microfibril length of 0.2 to 5 / zm and an average microfibril interval of 0.02 to 0.3 im.
- the outermost layer and the innermost layer serving as the support layer preferably have respective thicknesses in the range of 5 to 50 m, and similarly, the dense layer has the thickness of 3 to 15 xm. Is desirable. Further, it is also desirable that a coating layer made of a hydrophilic polymer is formed and a plurality of microfibrils are bound together.
- the initial water permeability is 25.0 L / (m- ⁇ hr ⁇ KPa) or more.
- a crystalline molten polymer is co-extruded from a die having three or more discharge ports arranged concentrically, and a composite unstretched having a laminated structure of three or more layers is provided.
- the hollow fiber is spun and stretched to a total draw ratio of 5 times or more.
- the crystalline molten polymer is co-extruded to form an outermost layer and an innermost layer (support layer) having a crystal orientation degree c of 0.8 to 0.99, and a crystal orientation degree of 0.2 to 0.2. It is desirable to spin a composite unstretched hollow fiber having an intermediate layer (dense layer) of 75 and stretch it.
- the hollow fiber membrane has a high fractionation accuracy, and when used for water filtration, exhibits sufficient bacterial fractionation characteristics.
- high permeation flow rates can be realized.
- the accumulated permeation flow rate is practically large enough to prevent clogging, and it is possible to extend the life of the membrane module and design the module with a small membrane area.
- a composite hollow fiber membrane subjected to a hydrophilic treatment is suitable as a water filtration membrane.
- the degree of orientation and size of the crystal can be controlled, and the fine pores formed in the dense layer and the support layer can be reduced.
- the desired size can be obtained, and both the water permeability and the separation accuracy can be stably improved.
- the filtration life can be further improved.
- the above-described composite hollow fiber membrane can be easily produced.
- the above-described high-performance composite fiber membrane can be produced.
- the stabilized hollow fiber membrane can be obtained stably.
- FIG. 1 is a partial perspective view showing an example of the composite hollow fiber membrane of the present invention.
- FIG. 2 is an enlarged plan view of the layers constituting the composite hollow fiber membrane.
- FIG. 3 is a side sectional view for explaining an example of a layer configuration.
- FIG. 4 is a side sectional view for explaining an example of a layer configuration.
- FIG. 5 is an enlarged plan view of the layers constituting the composite hollow fiber membrane subjected to the hydrophilic treatment.
- FIG. 6 is a plan view showing a method for measuring the average pore diameter of the micropores.
- Figure 7 is a graph of rejection versus latex particle diameter.
- the composite hollow fiber membrane of the present invention is a hollow fiber membrane in which at least three layers of a three-dimensional network structure are laminated, and the innermost layer located at the innermost side, the outermost layer located at the outermost side, and And an intermediate layer located between them. If the intermediate layer is one layer, it has a total of three layers, and if the intermediate layer is two or more, it has a configuration of four or more layers. In the present invention, both the innermost layer and the outermost layer are support layers, and it is essential that a dense layer be provided as an intermediate layer. Therefore, if the intermediate layer is a single layer, the composite hollow fiber membrane 10 has a three-layer structure of the outermost layer 12, the innermost layer 14, and the dense layer 16, as shown in FIG.
- Each layer is made of various thermoplastic resins such as polyamides, and among them, those made of polyolefin are preferable.
- thermoplastic resins such as polyamides, and among them, those made of polyolefin are preferable.
- high-density polyethylene having a high degree of crystallinity and few branches, isotactic polypropylene, poly (4-methyl-1-pentene), poly-3-methylbutene-1, polyvinylidene fluoride, and the like, and mixtures thereof can be mentioned.
- Density polyethylenes Japanese in Indus trial Standard (JIS) K 6 7 6 measuring method shown in 0, 0. 9 5 5 g Z cm is preferably 3 or more, more favorable Mashiku 0.9 6 0 g Z c rrp or more. If the density is less than 0.955 g / cn, it is difficult to form micropores by elongation, which is not preferable.
- JIS Japanese in Indus trial Standard
- the isotactic polypropylene has a tacticity of 96% or more, and the poly 4-methyl-1-pentene has a density of 0.830 to 0.8%. 835 g / cm 3 is preferred. With such a density and stereoregularity, it is easy to satisfy a crystal orientation degree fc described later in a specific range.
- the support layer and the intermediate layer have the same spinning temperature and spinning draft, and it is desirable to use the same kind of material, but it is not necessarily limited. Although it depends on the polymer used, the optimum conditions can be selected from, for example, a spinning temperature of 170 to 270 and a draft ratio of 100 to 600.
- the support layer and the intermediate layer have the same melt flow index (Ml: ASTM D-1238), which is one index of melt viscosity.
- the melt flow index is preferably from 0.1 to 50 gZlOmin, more preferably from 0.3 to 15 g / 10min. If it is less than 0.1 gZlOmin, the melt viscosity is too high, so that it is difficult to form a hollow fiber and it is difficult to form a hollow fiber membrane having fine pores. On the other hand, if it exceeds 50 gZlOmin, the melt viscosity is too low and shaping tends to be unstable.
- polymers that can be applied specifically, for example, as high-density polyethylene, as the polymer for the support layer, “Suntech B161” (manufactured by Asahi Kasei) (melt flow index 1.3 gZlOmiiu, density 0.966 c ⁇ ), “high-density polyethylene 310 ⁇ ” (Idemitsu Petrochemical) (Melt flow index 1.2 g / 10min, density 0.965 g / cn), "High density polyethylene HB530" (Mitsubishi Chemical)
- a number of micropores are formed by drawing a spun undrawn hollow fiber membrane.
- the stress is concentrated on the amorphous part where the structure is weak, and the Cleavage occurs between the lamellas, and at the same time, a part of the stacked lamella is also exfoliated, and these aggregate to form microfibrils.
- a number of microfibrils 20, 20,... Along the stretching direction and the stack lamellas 18, 18, 18 The slit-shaped micropores 22, 22, 22, '' are formed between the nodules.
- the pore diameter that is, the size of the micropores 22 is the average value of the length of the microfibrils 20 (corresponding to the length of the long side of the slit-shaped micropores or the distance between the stack dramers), and It is expressed by two parameters of the average value of the microfibril interval W.
- the permeation flow rate mainly depends on the length L of the microfibrils, and the longer the microfibrils, the higher the permeation flow rate.
- the fractionation accuracy mainly depends on the microfibril interval W, and the smaller the microfibril interval, the higher the fractionation accuracy.
- a support layer having fine pores having a relatively large pore size is disposed as the outermost layer and the innermost layer, and a dense layer having fine pores having a relatively small pore size is formed as an intermediate layer.
- the average microfibril length and the average microfibril interval for the micropores formed in the dense layer are defined as the average microfibril length and the average microfibril interval for the micropores formed in the support layer. Each smaller.
- each layer thickness is in the range of 5 to 50 m. Those that are within are desirable. If the layer thickness is less than 5 m, the durability against external pressure will be poor and it will be easy to deform. On the other hand, if the thickness is greater than 5, cooling delay is likely to occur in the thickness direction in the outer layer during the spinning process, and the degree of crystal orientation is likely to be disordered in the thickness direction. Dimensions are likely to be irregular across the thickness. As described above, in the composite hollow fiber membrane of the present invention, the thickness of the support layer is smaller than that of a conventional one. However, since it has a multi-layer structure of three or more layers, even if it is 50 m or less, it has sufficient crush resistance as a composite hollow fiber membrane.
- the layer thickness of the dense layer must be smaller than the layer thickness of the support layer. By making the layer thickness of the dense layer smaller than the layer thickness of the support layer, the permeation flow rate can be increased, and the filtration life can be improved.
- As the layer thickness of such a dense layer 3 to 15 tm is preferable. If it is thinner than ⁇ 3 / m, it is difficult to perform stable melt spinning, and if it is thicker than 15 im, it becomes a composite hollow fiber membrane. Is insufficient.
- the average microfibril length is preferably 0.5 to 10 m, and the average microfibril interval is preferably 0.1 to 0.6 / zm. If the microfibril length is less than 0.5 m or the microfibril interval is less than 0.1 zm, the permeation flow rate of the entire composite hollow fiber membrane becomes insufficient. On the other hand, if the microfibril length is longer than 10 m, the elongation at break of the hollow fiber membrane after stretching tends to be insufficient. Also, when the microfibril interval is wider than 0.6 im, the mechanical strength tends to be insufficient.
- the average microfibril length is preferably 0.2 to 5 m, and the average microfibril interval is preferably 0.02 to 0.3 m. If the microfibril length is less than 0.2 im or the microfibril interval is less than 0.02 im, the filtration resistance of the dense layer increases and the permeation flow rate of the entire composite hollow fiber membrane becomes insufficient. On the other hand, if the microfibril length is longer than 5 iim, the mechanical strength of the dense layer tends to be insufficient, and if the microfibril interval is wider than 0.3 m, the separation accuracy tends to decrease as a composite hollow fiber membrane.
- the microfibril length and the microfibril (bundle) interval can be measured, for example, as follows.
- the porous membrane to be measured is cut out as an ultrathin section along the stretching direction to obtain a sample, and the sample is taken into an image processing apparatus at a magnification of 6500 using a transmission electron microscope. Then, as shown in FIG. 6, n scanning lines are drawn on the captured image at a constant pitch (for example, 0.052 // m). At this time, for each scanning line, sum the lengths of the line segments on the micropores 22, for example, al, a2, a3, ... (Sum of distances). Similarly, for each scanning line, for example, bl, b2, b3,.
- the micropore 22 ′ may be excluded.
- the number of micropores 22, 22, ... that each scanning line has passed is calculated (sum of numbers). For example, in FIG. 6, the number is 5 for the first scan line, 6 for the second scan line, and 6 for the n-th scan line. Then, the distance sum is divided by the number sum (distance sum number sum). In this measurement, if the scanning direction of the scanning line is perpendicular to the stretching direction, the microfibril (bundle) interval is determined. If the scanning direction of the scanning line is parallel to the stretching direction, the microfibril length is determined.
- the intermediate layer not only one dense layer is formed, but also, for example, as shown in FIG. 3, two dense layers 16 are formed between the outermost layer 12 and the innermost layer 14, or As shown in FIG. 4, a dense layer 16 and a layer 17 having characteristics intermediate between the support layer and the dense layer may be formed between the outermost layer 12 and the innermost layer 14. Unless a layer denser than the outermost layer 12 is formed outside the layer 2, a layer configuration of four or more layers of various patterns can be adopted.
- the composite hollow fiber membrane of the present invention has a three-layer structure or a structure of four or more layers, and a dense layer exhibiting the best filtration function is positioned as an intermediate layer.
- a dense layer exhibiting the best filtration function is positioned as an intermediate layer.
- the dense layer is the outermost layer. Because it is not arranged in layers, it is difficult to clog.
- the conventional composite hollow fiber membrane having a two-layer structure if the dense layer is disposed in the innermost layer, it is difficult to control the degree of crystal orientation within a predetermined range, and the dense layer is formed in the dense layer.
- the resulting micropore size was non-uniform (the pore size distribution was wide) and the fractionation accuracy was low.
- the dense layer is arranged as the intermediate layer, it is located on the outer side than the innermost layer, so that the cooling rate of the dense layer at the time of spinning becomes faster, and the degree of orientation is reduced. And the degree of crystal orientation is stabilized. As a result, the pore size of the formed micropores becomes uniform (the pore size distribution is narrow), and the separation accuracy is improved.
- the configuration of three or more layers facilitates control of the degree of crystal orientation in both the support layer and the dense layer. And both filtration life and fractionation accuracy can be improved.
- the composite hollow fiber membrane preferably has an inner diameter in the range of 50 to 500. If the inner diameter is less than 50 m, the pressure loss inside the hollow fiber membrane becomes large, which is not preferable for practical use. On the other hand, when it is larger than 500 / m, the degree of integration of the hollow fiber membranes is reduced, so that the water permeability per unit volume is significantly reduced.
- the total thickness is preferably from 5 to 500 / m, and more preferably from 30 to 200 / m. If the total thickness is less than 5 zm, the mechanical strength is weak, and flattening of the hollow fiber occurs. On the other hand, when it is larger than 200, it is difficult to obtain high water permeability.
- the composite hollow fiber membrane of the present invention has a porosity of 75 vol% or more.
- the filtration life can be extended. Further, the filtration life is further improved by increasing the initial membrane permeation flow rate (permeate amount), preferably by setting the initial permeate amount to 25. OL / (m ⁇ ⁇ hr ⁇ KPa) or more. Can be done.
- the initial permeation flow rate water permeation rate
- the initial permeation flow rate can be increased by increasing the microfibril length of the micropores in the support layer and decreasing the thickness of the dense layer.
- the composite hollow fiber membrane of the present invention is produced, for example, as follows.
- a composite unstretched hollow fiber (unstretched yarn) having a configuration in which the intermediate layer containing the polymer is laminated is produced.
- the polymer for the support layer (the polymer for the outermost layer and the inner layer) and the polymer for the dense layer (the polymer for the intermediate layer) are individually extruded and cooled, the polymer consisting of the polymer for the support layer is not obtained.
- the crystal orientation degree fc of the drawn hollow fiber may be set to 0.8 to 0.99, and the crystal orientation degree fc of the undrawn hollow fiber made of the polymer for the dense layer may be set to 0.2 to 0.75. desirable.
- the degree of crystal orientation ⁇ c increases and approaches 1.0, the degree of order in which the lamellar crystal aggregates are oriented in the fiber axis direction increases, and the statistical size of the lamellar aggregates in the fiber axis direction increases. , For stretching Therefore, the microfibril length can be increased in the fiber axis direction.
- a composite hollow having a support layer having relatively large micropores and a dense layer having small micropores is obtained. It can be made into a yarn membrane, and can exhibit both high water permeability and high fractionation characteristics.
- the crystal orientation degree which indicates the degree of orientation of the crystal axis with respect to the fiber axis direction, Is defined as follows:
- ⁇ C OS 2 (3 ⁇ 4) is given by the following equation.
- I ( h ..) represents the intensity distribution along the (hOO) plane diffraction Debye ring, and 0 h . . Is the Bragg angle of (h 00) plane diffraction. Yu h. . Is the azimuth along the (hOO) plane diffraction Debye ring.
- the stretching process is a two-stage stretching of cold stretching at room temperature and hot stretching under heating, Alternatively, multi-stage stretching in which the thermal stretching is further divided into multiple stages is desirable.
- the cold stretching and the hot stretching may be performed by using a well-known porous method.
- the total stretching ratio (cold stretching ratio ⁇ hot stretching ratio) is desirably 5 or more, and may be 5.5 to 15 times. More preferred.
- the stretching ratio is desirably 5 times or more, and may be 5.5 to 15 times. More preferred.
- the porosity of the entire membrane can be 75 vol% or more, and the initial water permeability and the accumulated water permeability can be increased. If the draw ratio exceeds 15 times, the elongation of the hollow fiber membrane is less than practical and not suitable.
- the optimal conditions for the deformation rate of the hot stretching differ depending on the polymer used, it is preferable to perform the deformation in the range of 0.01 to 10 min. If it is smaller than 0.0 lmin- ', undrawn yarn is likely to break, and if it is larger than 1 Omin-', it is difficult to achieve the above porosity, which is inappropriate.
- heat setting may be performed under a fixed length or in a state where the film is slightly relaxed to relax the stress.
- the heat setting temperature is higher than the stretching temperature within a range not exceeding the melting point.
- the molecular mobility of the molten polymer molecular chains decreases (the melt viscosity increases).
- Folded crystal growth of molecular chains (lamellar crystal growth) competes. It is considered that the degree of crystal orientation (orientation order of lamellar crystals) in the composite undrawn hollow fiber is determined when the two phenomena reach an equilibrium with the progress of cooling.
- the isothermal crystallization time ⁇ is defined as an end point at which a molecular chain crystallizes into a spherulite under isothermal conditions, spherulites grow, and adjacent spherulites collide with each other and stop growing. Then, say 1 Z 2 of the time to reach this end point.
- the crystal structure of the composite unstretched hollow fiber of the present invention is a form in which lamellar crystals are screened in the fiber axis direction, and is not a spherulite structure at the time of isothermal crystallization. This is one index for quantifying the growth rate of the folded crystal.
- the present invention has been made by finding that the size of the lamellar crystal corresponds to the size of the microfibril length after stretching. In the later hollow yarn, the microfibril length of the support layer can be made longer than the microfibril length of the dense layer.
- the lamella in the dense layer can be obtained.
- the crystal size is smaller than the lamellar crystal size of the support layer. Therefore, the length of the microfibrils in the dense layer is shorter than the length of the microfibrils in the support layer, and as a result, the micropores in the dense layer are smaller than the micropores in the support layer. Therefore, both water permeability and fractionation accuracy can be improved.
- the above-described composite hollow fiber membrane can be used as it is as an air filter and mist filter, but when used as a water filtration membrane, the microporous surface is coated with a hydrophilic polymer and It is desirable to make it easy to get wet. That is, a coating layer made of a hydrophilic polymer is formed on the knot portion of the stack dramella of the composite hollow fiber membrane and the surface of the microfibril.
- hydrophilic polymer a copolymer containing at least 20 mol% of ethylene and at least 10 mol% of a hydrophilic monomer is preferable.
- copolymers may be any type of copolymer such as a random copolymer, a block copolymer, and a graft copolymer. If the ethylene content in the copolymer is less than 20 mol%, The union is unfavorable because it has a low affinity for the composite hollow fiber membrane and it is difficult to sufficiently form a coating layer made of a hydrophilic polymer.
- hydrophilic polymer examples include ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyvinylpyrrolidone, and a hydrolyzate of polyvinyl acetate.
- the hydrophilic copolymer may contain at least one third component other than ethylene and the hydrophilic monomer.
- a third component include vinyl acetate, (meth) acrylate, and the like.
- examples thereof include vinyl alcohol fatty acid esters, formalized products of vinyl alcohol, and bratylated products.
- the solvent for the hydrophilic copolymer is preferably a water-miscible organic solvent, and specific examples thereof include water, methanol, ethanol, n-propanol, isopropyl alcohol, butanol, and alcohols such as ethylene glycol. And dimethylsulfoxide, dimethylformamide and the like. These solvents can be used alone, but a mixture with water is more preferable because of its high solubility in the hydrophilic copolymer.
- the boiling point of the solvent is low when the hollow fiber membrane coated with the hydrophilic copolymer is dried, because the solvent has a low vapor pressure and low toxicity to the human body. It is particularly preferable to use a mixed solvent of water and alcohol such as methanol, ethanol, isopropyl alcohol and the like.
- the mixing ratio of the water-miscible organic solvent and water may be within a range that does not inhibit the permeability of the composite hollow fiber membrane and does not decrease the dissolution of the copolymer. If ethanol is used as the organic solvent, Preferably, the ratio of knol / water is in the range of SOZ l OSOZ i O (vol%).
- the concentration of the hydrophilic copolymer solution ranges from about 0.1 to 10% by weight, preferably from 0.5 to 5% by weight. It is difficult to coat the hydrophilic copolymer uniformly with a solution having a concentration of less than 0.1% by weight with a hydrophilic treatment. If the concentration exceeds 10% by weight, the solution viscosity becomes too large and the solution becomes hydrophilic. When the coagulation treatment is performed, the micropores of the composite hollow fiber membrane are closed by the copolymer.
- a coating method a conventionally known method of immersing the composite hollow fiber membrane in a hydrophilic polymer solution, pulling it up, and evaporating and drying the solvent by heating and drying can be applied.
- the immersion treatment may be performed twice or more in the copolymer solution having the same concentration, or the immersion may be performed two or more times in a solution having a different concentration.
- the temperature of the hydrophilic copolymer solution to be subjected to the immersion treatment the lower the viscosity, and the better the permeability of the solution to the composite hollow fiber membrane, which is preferable.
- the temperature is lower than the boiling point of the solution. Preferably, there is.
- the immersion treatment time varies depending on the thickness of the composite hollow fiber membrane used, the pore size, and the porosity, but is preferably in the range of several seconds to several minutes.
- the coating amount of the hydrophilic copolymer is preferably in the range of 3 to 30% by weight in terms of weight with respect to the composite hollow fiber membrane before the hydrophilic treatment. If the coating amount of the hydrophilic copolymer is less than 3% by weight, the affinity for water is poor and water permeability to the membrane is insufficient. On the other hand, the coating amount of the hydrophilic copolymer is 30% by weight. If the amount exceeds the above, the pores are easily blocked by the copolymer, and the water permeability tends to decrease.
- microfibril bundle 21 When this hydrophilization treatment is performed, as shown in FIG. 5, a plurality of microfibrils are bound together to form a microfibril bundle 21, and the micropores 22 change from a slit shape to an elliptical shape.
- the average distance Da between the microfibril bundles with respect to the size of the micropores in the dense layer is 0.02 to 0.6 zm. It is preferably, and more preferably 0.2 to 0.4 / m. If the average distance Da between the microfibril bundles exceeds 0.6 m, the fractionation accuracy tends to be insufficient, and if Da is less than 0.02 m, the permeation flow rate of the entire composite hollow fiber membrane is insufficient for practical use. Easy to do, not preferred.
- the average distance Db between the microfibril bundles is preferably from 0 :! to 1 m, and more preferably from 0.4 to 0.5 / zm.
- Db the average distance between the microfibril bundles
- the water permeation rate tends to decrease
- Db exceeds 1 ⁇ the mechanical strength of the hollow fiber membrane tends to decrease. It is in.
- the microfibril length M in the support layer is preferably from 0.4 to 10 im, more preferably from 0.7 to 5.0 / m.
- the water permeation rate tends to decrease in a hollow fiber membrane having a support layer with micropores with a microfibril length M of less than 0.4, and when the microfibril length M exceeds 10 / zm, the mechanical strength of the hollow fiber membrane Tends to decrease.
- the rejection that is, fractionation accuracy
- polystyrene latex standard particles having a particle diameter of 0.05 to 0.3 can be 90% or more.
- the composite hollow fiber membrane of the present invention when used for filtration of tap water, when the differential pressure on both sides of the membrane is 98 KPa, the initial water permeability is 25.0 LZ (m--hr KP a) or more, and the integrated flow rate through the membrane until the water permeability decreases to 50% of the initial value can be 35.0 L (m ⁇ -KP a) or more. It is unlikely to be clogged during continuous water flow and has a sufficient filtration life.
- High-density polyethylene (“Suntech B 161” manufactured by Asahi Kasei: Melt-Fund TM 1.3 g / 10 min, density 0.966 gZcm3) as a polymer for the support layer, and high-density polyethylene (“Nipolon Hard 5110”) as the polymer for the dense layer East Soichi Manufacture: Meltoff® Index 0.90 g / 10min, density 0.960 g / cn).
- the molten polymer for the supporting layer is the innermost layer and the outermost layer of the hollow fiber production nozzle having three concentrically arranged annular discharge ports, and the molten polymer for the dense layer is in the middle discharge port.
- the polymer was extruded from the discharge port while maintaining the temperature of the polymer at 170, it was cooled and wound up at a draft ratio of 650 to produce a composite undrawn hollow fiber.
- the composite undrawn hollow fiber was left at 115 for 12 hours and subjected to thermal annealing.
- the polymer for the support layer and the polymer for the dense layer were independently spun at the same spinning temperature, cooling conditions, and draft ratio in advance, and the obtained undrawn hollow fiber was subjected to an X-ray diffractometer. (“Model RU200” manufactured by Rigaku Denki) was used to measure the degree of crystal orientation, and it was confirmed that the degree of crystal orientation was as shown in Table 3.
- the composite undrawn hollow fiber was subjected to cold drawing at room temperature, and then to hot drawing at 110 to obtain a composite hollow fiber membrane having a three-layer structure.
- the obtained composite hollow fiber membrane was dissolved in a solution (0.8 wt% solute concentration) in which an ethylene-vinyl alcohol copolymer (“Soanol DC 32” manufactured by Nippon Gohsei) was dissolved in an alcohol / water mixed solvent.
- a solution 0.8 wt% solute concentration
- an ethylene-vinyl alcohol copolymer (“Soanol DC 32” manufactured by Nippon Gohsei) was dissolved in an alcohol / water mixed solvent.
- the porosity, initial air flux, and initial water permeability were determined. It was measured. The fractionation accuracy was measured for Examples 1 to 3, and the results are shown in FIG. 7 by line A (Example 1), line B (Example 2), and line C (Example 3). Furthermore, after filling the micropores of the hollow fiber membrane with resin, a cross section of the membrane along the fiber axis is cut out, the cross section of the membrane is observed with a scanning electron microscope, and the thickness of the support layer, the thickness of the dense layer, and the thickness of each layer are measured. The average micropore size (microfibril length, microfibril spacing) was measured. In addition, a continuous water flow test was performed as an indicator of the degree of clogging.
- Isofine Polypropylene (“HIPOL CJ 700”, manufactured by Mitsui Chemicals: density 0.91 g / cn, MI: 3.0, 98% iso-isocity), and “FINA3230B HOMOPOLYMERj (F (Made by INA) (density 0.905 gZcm3, MI: 1.6, isoactivity 97%).
- the innermost layer and the outermost layer of the hollow fiber manufacturing nozzle having three concentrically arranged tubular discharge ports are provided with the molten polymer for the support layer at the discharge port located in the middle and the molten polymer serving as the dense layer at the discharge port located in the middle.
- the polymer was fed and extruded from the discharge port while maintaining the temperature of the polymer at 190, then cooled and wound up at a draft ratio of 200 to produce a composite undrawn hollow fiber.
- the composite undrawn hollow fiber was left at 135 under 12 hours, and was subjected to thermal annealing.
- Thermal stretching was performed with 3 O: to obtain a composite hollow fiber membrane having a three-layer structure.
- the obtained composite hollow fiber membrane is immersed in a solution (0.8 wt% solute concentration) in which an ethylene-vinyl alcohol copolymer (“Soanol DC 32” manufactured by Nippon Synthetic Chemical) is dissolved in a mixed solvent of alcohol Z water. Then, the hollow fiber membrane was dried at 65 ° C. while pulling up, and the solvent was evaporated to prepare a composite hollow fiber membrane subjected to a hydrophilic treatment.
- a solution 0.8 wt% solute concentration
- an ethylene-vinyl alcohol copolymer (“Soanol DC 32” manufactured by Nippon Synthetic Chemical)
- the porosity, initial air flux, and initial water permeability of this membrane were measured. After filling the micropores of the hollow fiber membrane with resin, a section of the membrane along the fiber axis is cut out, and the section of the membrane is observed with a scanning electron microscope. The thickness of the support layer, the thickness of the dense layer, and the flatness of each layer are measured. The uniform pore size (microfibril length, microfibril interval) was measured. Ma A continuous water flow test was also performed.
- the molten polymer for the support layer (Suntech B 16) was placed on the outer layer outlet of a hollow fiber manufacturing nozzle having two concentrically arranged annular outlets. 1) was supplied to the inner layer discharge port with the molten polymer for dense layer (two-pole hard 5110), extruded from the discharge port while keeping the temperature of the polymer at 170, cooled, and cooled to a draft ratio of 6 Winding was performed at 50 to produce a composite undrawn hollow fiber. Next, in order to improve the crystal orientation order, the composite undrawn hollow fiber was left under 115 for 12 hours to perform thermal annealing.
- the composite undrawn hollow fiber was subjected to cold drawing at room temperature, and then subjected to hot drawing at 110 to obtain a composite hollow fiber membrane having a two-layer structure.
- the composite hollow fiber membrane was immersed in a solution (0.8 wt% solute concentration) in which an ethylene-vinyl alcohol copolymer (“Soanol DC32” manufactured by Nippon Gohsei) was dissolved in a mixed solvent of alcohol Z water. Then, the hollow fiber membrane was dried at 65 while being pulled up, and the solvent was evaporated to prepare a composite hollow fiber membrane that had been subjected to a hydrophilic treatment.
- a solution 0.8 wt% solute concentration
- an ethylene-vinyl alcohol copolymer (“Soanol DC32” manufactured by Nippon Gohsei) was dissolved in a mixed solvent of alcohol Z water.
- the porosity, initial air flux, and initial water permeability of this membrane were measured.
- the fractionation accuracy was measured, and is indicated by a line D in FIG.
- the cross section of the membrane was observed with a scanning electron microscope, and the thickness of the support layer, the thickness of the dense layer, and the average micropore size (microfibril length, microfibril interval) of each layer were measured.
- a continuous water flow test was also performed.
- the crystal orientation degree fc value of each layer cannot be directly obtained, but the polymer of each layer is spun alone into the undrawn fiber (draft ratio 100 to 700).
- the dense layer of the composite hollow fiber membrane had a draft ratio of substantially 1. It turned out to be equivalent to 50. Therefore, the crystal orientation degree f c value of the dense layer at this draft ratio was estimated from the crystal orientation degree f c value of the single spun product, and shown in Table 3.
- molten polymer for the support layer (Suntech B 161) is placed at the inner layer outlet of a hollow fiber production nozzle with two annular outlets, and the molten polymer (Niboron Hard 5110) carries the dense layer at the outlet located at the outer layer. After the polymer was extruded from the discharge port while maintaining the temperature of the polymer at 170, it was cooled and wound up at a draft ratio of 650 to produce a composite undrawn hollow fiber.
- the composite undrawn hollow fiber was allowed to stand at 115 at 12 hours for thermal annealing.
- the undrawn composite hollow fiber was cold-drawn at room temperature, and then hot-drawn at 110 to obtain a composite hollow fiber membrane having a two-layer structure.
- the composite hollow fiber membrane was immersed in a solution (solute concentration: 0.8 wt%) of an ethylene-vinyl alcohol copolymer (“Soanol DC 32” manufactured by Nippon Synthetic Chemical) dissolved in a mixed solvent of alcohol and water. While lifting the membrane, it was dried at 65 ° C and the solvent was evaporated to produce a hydrophilized composite hollow fiber membrane.
- Sol DC 32 ethylene-vinyl alcohol copolymer manufactured by Nippon Synthetic Chemical
- the porosity, initial air flux, and initial water permeability of this membrane were measured.
- the cross section of the membrane was observed with a scanning electron microscope, and the thickness of the support layer, the thickness of the dense layer, and the average micropore size (microfibril length, microfibril interval) of each layer were measured.
- a continuous water flow test was performed, the accumulated water flow was measured, and the evaluation results of the hollow fiber membranes were summarized in Tables 1-3.
- Hizex 2200JJ manufactured by Mitsui Petrochemical, Ml: 5.5 g / lOmin
- undrawn hollow fibers consisting of a single-layer membrane were produced at a spinning temperature of 157 and a draft ratio of 2500.
- the hollow fiber was allowed to stand at 111 for 16 hours and subjected to thermal annealing.
- the undrawn hollow fiber after annealing was cold-drawn at room temperature, and then hot-rolled at 110 to obtain a single-layer hollow fiber membrane.
- the hot stretching deformation rate was set to 2.6 min in Comparative Example 3 and 2.2 min in Comparative Example 4.
- Microfibril length, microfibril interval were measured. A continuous water flow test was also performed.
- the measuring method of each evaluation is as follows.
- the weight of the membrane was measured in a state where the toluene was infiltrated into the micropores of the hollow fiber membrane, and then the butanol penetrating was removed with a stretching separator.
- the porosity of the entire hollow fiber membrane was determined from the volume of the water and the volume of the permeated butanol.
- a hollow fiber membrane with an effective length of 10 cm is bundled with potting resin for 80 cm2 for 2 minutes, and tap water from Nagoya, Aichi, Japan is passed through the membrane bundle at a pressure of 98 KPa from the outside of the membrane. Then, the time-dependent change in the amount of water permeating from the inside of the membrane was measured, and the accumulated amount of water passing through the membrane until this amount of water dropped to 50% of the initial value was determined.
- the hollow fiber membrane of the present invention has a high fractionation accuracy, and when used for water filtration, exhibits sufficient bacterial fractionation characteristics.
- a high permeation flow rate can be realized at the same time.
- the accumulated permeation flow rate is practically large enough to prevent clogging, and it is possible to extend the life of the membrane module and design the module with a small membrane area.
- a composite hollow fiber membrane subjected to a hydrophilic treatment is suitable as a water filtration membrane.
- the degree of orientation and size of the crystal can be controlled, and the fine pores formed in the dense layer and the support layer can be reduced.
- the desired size can be obtained, and both the water permeability and the separation accuracy can be stably improved.
- the filtration life can be further improved.
- the above-described composite hollow fiber membrane can be easily produced.
- the above-described high-performance composite fiber membrane can be produced.
- the stabilized hollow fiber membrane can be obtained stably.
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WO2020228328A1 (zh) * | 2019-05-10 | 2020-11-19 | 北京工业大学 | 一种中空纤维膜及其制备方法和应用 |
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US7306105B2 (en) | 2002-11-12 | 2007-12-11 | Mitsubishi Rayon Co., Ltd. | Composite porous membrane and method for producing the same |
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EP2060315A3 (en) | 2007-11-15 | 2009-08-12 | DSMIP Assets B.V. | High performance membrane |
JP5292890B2 (ja) * | 2008-03-31 | 2013-09-18 | 東レ株式会社 | 複合中空糸膜 |
JP5873497B2 (ja) | 2010-09-17 | 2016-03-01 | ケンブリッジ エンタープライズ リミテッド | ナノ多孔質材料、その製造方法及びその応用 |
JP6370021B2 (ja) * | 2012-03-30 | 2018-08-08 | 三菱ケミカル株式会社 | 脱気複合中空糸膜及び中空糸膜モジュール |
CN102773024B (zh) * | 2012-05-07 | 2014-12-10 | 苏州信望膜技术有限公司 | 一种中空纤维式正渗透膜的制备方法 |
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JPH03169330A (ja) * | 1989-11-30 | 1991-07-23 | Mitsubishi Rayon Co Ltd | 複合膜 |
JPH03296424A (ja) * | 1990-04-16 | 1991-12-27 | Mitsubishi Rayon Co Ltd | 多層複合膜 |
JPH09117643A (ja) * | 1995-08-18 | 1997-05-06 | Mitsubishi Rayon Co Ltd | 中空糸膜モジュール |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995019219A1 (fr) * | 1994-01-17 | 1995-07-20 | Mitsubishi Rayon Co., Ltd. | Film de polyolefine microporeux composite et procede de production de ce film |
-
1998
- 1998-03-13 JP JP10063648A patent/JPH11253768A/ja active Pending
-
1999
- 1999-03-12 TW TW088103904A patent/TW406030B/zh not_active IP Right Cessation
- 1999-03-15 EP EP99907929A patent/EP1063004A4/en not_active Withdrawn
- 1999-03-15 WO PCT/JP1999/001245 patent/WO1999046034A1/ja active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH03169330A (ja) * | 1989-11-30 | 1991-07-23 | Mitsubishi Rayon Co Ltd | 複合膜 |
JPH03296424A (ja) * | 1990-04-16 | 1991-12-27 | Mitsubishi Rayon Co Ltd | 多層複合膜 |
JPH09117643A (ja) * | 1995-08-18 | 1997-05-06 | Mitsubishi Rayon Co Ltd | 中空糸膜モジュール |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR101036312B1 (ko) * | 2008-07-11 | 2011-05-23 | 양익배 | 비대칭 중공사 분리막 및 그 제조방법 |
WO2020228328A1 (zh) * | 2019-05-10 | 2020-11-19 | 北京工业大学 | 一种中空纤维膜及其制备方法和应用 |
Also Published As
Publication number | Publication date |
---|---|
TW406030B (en) | 2000-09-21 |
EP1063004A4 (en) | 2002-02-27 |
EP1063004A1 (en) | 2000-12-27 |
JPH11253768A (ja) | 1999-09-21 |
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