JP3432263B2 - Multilayer microporous hollow fiber membrane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention has excellent separation and filtration performance.
The present invention relates to a multilayer microporous hollow fiber membrane obtained by the method described above. [0002] 2. Description of the Related Art In recent years, resource saving, energy saving, separation and purification.
The separation method using microporous hollow fiber membrane is rapid from the viewpoint of
Has come to be used on a practical scale. like this
One of the uses of microporous hollow fiber membranes is water purifier
it can. The above-mentioned hollow fiber to be installed at the faucet of each household
A water purifier incorporating a membrane as a filtration membrane is easy to use.
It is becoming popular. [0003] By the way, such a microporous hollow fiber membrane is
Many researches have been conducted on
Polymers such as ter, polyolefin, and polysulfone
Materials consisting of materials have been proposed. In particular, JP
Japanese Patent Application Laid-Open No. 79806/1992 discloses a micro-permeation having a predetermined pore diameter.
The first porous layer made of a thermoplastic resin having pores is provided with the pores.
Specific thermoplastics with microporous pores larger than the diameter
It has a multilayer structure in which a second porous layer made of resin is laminated.
Hollow fiber membranes have good separation ability and are suitable. here,
In the hollow fiber membrane having the multilayer structure, each porous layer
The formed pores can be sufficiently formed by high-speed deposition during melt deposition.
Heat treatment of undrawn hollow fiber with internal strain
After increasing the crystallinity of
Voids are generated, and the obtained drawn hollow fiber is solidified.
The so-called stretching-heat, where heat treatment is performed while maintaining a fixed end
Formed by going through a complex process of processing
I have. [0004] SUMMARY OF THE INVENTION These conventional proposals have been made.
Water that incorporates a microporous hollow fiber membrane as a filtration membrane
The vessel has a certain amount of initial water permeability,
It is said that membrane clogging occurs and the water permeability gradually decreases
There were drawbacks. This problem is caused by the crystallinity of the material resin.
Has a specific multilayer structure obtained by drawing a hollow fiber with increased
Using hollow fiber membranes as filtration membranes for water purifiers
Also occurs remarkably, so that in order to obtain a desired water permeability
Had to change the membrane frequently. [0005] From the above background, a film obtained by a simple method
It has a large initial water permeability and can be used for a long time.
Development of microporous hollow fiber membrane with small decrease in water permeability is desired
I was [0006] Means for Solving the Problems The present inventors have solved the above problems.
In light of the subject, I have been conducting diligent research. As a result, polio
Inorganic filling surface treated with silicone oil on refins
Of the resin layer composed of a mixture containing a large amount of
Specific arrangement of two layers with different average particle size of filler
Forming the composite resin film laminated in a hollow shape and stretching it
The multi-layer microporous hollow fiber membrane obtained by
They have found that they have added them and completed the present invention. That is, the present invention relates to polyolefins 10 to 7
0% by weight and average particles dispersed in the polyolefin
Child diameter is 0.01 to 5 μmof,Surface treatment with silicone oil
90 to 30% by weight of inorganic filler
It has a network structure consisting of communicating holes with a hole diameter of 5 μm or less,
Molecular orientation by elongationStack two microporous layers
And the two layers areAverage particle size and ream of inorganic filler
Average hole diameter of through hole is differentAndAverage particle size of the inorganic filler
The layer with the larger diameter and the average hole diameter of the communication hole is located on the outer surface side.
Place,Multi-layer microporous with small layers located on the hollow side
It is a hollow fiber membrane. [0008] In the present invention, the multi-layer microporous hollow fiber membrane
Polyolefins used as raw materials include polyethylene and polyethylene.
Propylene, polybutene-1 or polymethylpentene
Α-olefin homopolymer such as α-olefin and other
With copolymerizable monomers and their mixtures
Objects and the like. Among them, the obtained multi-layer
Considering the heat resistance and moldability of the porous hollow fiber membrane,
Homopolymer, propylene and other copolymerizable monomers
And copolymers thereof are preferred. The above α-olefin and other copolymerizable
Copolymers with monomers are generally α-olefins, especially
Other copolymerizable polymer containing 90% by weight or more of propylene
A copolymer containing 10% by weight or less of a nomer is preferable. Ma
Further, the copolymerizable monomer is not particularly limited, and is known.
Can be used, but generally, those having 2 to 8 carbon atoms
α-olefins, particularly ethylene, and butene are suitable.
is there. In the present invention, the inorganic filler is used in the stretching step.
Between polyolefin and dispersed inorganic filler in
To form fine communication holes
used. Agglomerates when mixed with polyolefin
It is preferable that they are uniformly dispersed. The above-mentioned inorganic filler exhibits the above-mentioned functions.
Any material can be used without any particular limitation.
Table IIA, IIIA, IVA and IVB
Oxide, hydroxide, carbonic acid of one metal selected from the group
Fillers made of salts or sulfates are preferred. these
As the filler, those known as fillers of various synthetic resins can be used.
Can be used without limitation, but those generally used preferably
Is as follows. For example, Periodic Table IIA
Group metals such as calcium, magnesium and barium
And the like, and as a Group IIIA metal
Is a metal such as boron, aluminum, etc .;
Metals such as titanium, zirconium and hafnium
And metals such as silicon as Group IVA metals.
It is suitable. Oxides, hydroxides, carbonates of these metals
Salts or sulfates can be used without particular limitation. Especially suitable
More specifically, the filler used is, for example, oxide oxide.
Cium, magnesium oxide, boron oxide, titanium oxide,
Oxides such as zirconium oxide and silica; calcium carbonate
Carbonates such as calcium carbonate, magnesium carbonate and barium carbonate;
Magnesium fluoride, calcium hydroxide, aluminum hydroxide
Hydroxides such as calcium; calcium sulfate, barium sulfate, sulfuric acid
Sulfates such as aluminum; calcium silicate, aluminum silicate
It is a silicate such as ruminium or talc. The above inorganic filler is represented by silicone oil.
It is important that the surface is treated. As a surface treatment agent
The silicone oil used is represented by the following general formula.
Is polydimethylsiloxane. [0013] Embedded image (However, R¹And R^TwoIs a hydrogen atom,
Is a substituted or unsubstituted alkyl group having 1 to 25 carbon atoms,
An alkenyl group and a phenyl group. In the present invention,
Specific compound names of silicone oils that can be suitably used
For example, polydimethylsiloxane, polydisiloxane
Ethyl siloxane, polydipropyl siloxane, polydi
Phenylsiloxane, polymethylhydrogensiloxy
Sun, polymethyl hydrogen siloxane, polyfe
Nil hydrogen siloxane and the like.
You. The average molecular weight of silicone oil is not limited
Not melted, but melt-kneaded with polyolefin
To prevent volatilization due to heat, and a uniform surface of inorganic filler
In order to perform surface treatment, generally, 1,000 to 100,0
00 is preferably used. The amount of the silicone oil surface treating agent used
Is not particularly limited, but for stretching a polyolefin composition
Interface separation at the interface with the inorganic filler due to
Above, generally, 0.1 parts by weight per 100 parts by weight of the inorganic filler.
A range of 5 to 5 parts by weight is preferred. As a surface treatment method, an inorganic filler and a silica
Simply mix with the corn oil. For example, Sue
Add a certain amount of inorganic filler and silicone oil
And 1,000 to 2,000 rpm for 2 to 5 minutes
After high-speed stirring for 2-4 hours at 190-210 ° C.
The method of processing can be suitably adopted in the present invention. The surface treated with the above silicone oil
The average particle size of the inorganic filler must be 0.01 to 5 μm.
It is necessary. When this average particle size is out of the above range
Has an inorganic filler surface treated with the above silicone oil
Material is difficult to disperse in polyolefin
The maximum pore size of the hollow fiber membrane
Germs, for example, E. coli
Become. To obtain a multilayer microporous hollow fiber membrane suitably employed
For this purpose, use an inorganic filler that has been surface-treated with this silicone oil.
The average particle size of the material is preferably 0.03 to 4 μm.
New The above-mentioned polyolefin and silicone oil
% Of the inorganic filler surface-treated with
10 to 70% by weight, preferably 15 to 60% by weight
And the inorganic filler is 90 to 30% by weight, preferably 8% by weight.
5 to 40% by weight. With this polyolefin and silicone oil
Composition ratio with surface-treated inorganic filler is multi-layer microporous
The properties of each microporous layer constituting the porous hollow fiber membrane to a specific range
Important for industrially advantageous production of hollow fiber membranes.
is there. The ratio of the inorganic filler is less than the lower limit.
And the formation of pores in the microporous layer is not sufficient.
When the addition ratio of the filler component exceeds the upper limit, hollow
The formability of the yarn membrane may be poor, or the drawing may not be performed sufficiently.
Any tendency is not preferable. In the present invention, this polyolefin and silicone
Mixture with inorganic filler surface treated with corn oil
The microporous layer that constitutes each layer of the multilayer microporous hollow fiber membrane
The active layer is molecularly oriented by stretching. As a result,
The microporous layer is the interface between the polyolefin and the inorganic filler.
Is peeled off, and a communication hole having a maximum pore diameter of 5 μm or less is formed in the layer.
It is formed in a net shape. The chains formed in this microporous layer
When the maximum pore diameter of the through hole exceeds 5 μm, it is obtained.
Although the water permeability of the multilayer microporous hollow fiber membrane such as water is good
Liquid / solid, liquid / gas, liquid / liquid, and gas
/ Preferred because it reduces the separation performance between solids
I don't. In the present invention, the suitability of water permeability such as clean water
If considered, the maximum pore diameter is 0.01 to 3 μm
Is preferred. The communication formed in this microporous layer
The pores usually have an average pore diameter of 0.005 to 3 μm.
You. The multilayer microporous hollow fiber membrane of the present invention is
The surface of the porous layer is treated with the silicone oil.
The average particle size of the inorganic fillers
Two layers having different average diameters of the communication holes are stacked. This
Here, the interfacial separation between the polyolefin and the inorganic filler
The pores formed usually have an average particle size of the inorganic filler.
Smaller is finer pores, larger is larger
It becomes a hole of a diameter. Thus, in the present invention, the above silicone
The average particle size of the inorganic filler surface-treated with oil is different
And the average diameter of the communication holes varies accordingly.
Porous membrane, the average particle diameter of the inorganic filler and the average of the communication holes
The larger layer is on the outer surface, while the smaller layer is on the hollow surface.
It is laminated so that it is located on the side, and a hollow fiber membrane is obtained. like this
Surface treated with polyolefin and silicone oil
Different average pores constituted by interfacial delamination of inorganic filler
The two microporous layers having communicating holes having the same diameters are formed as described above.
By laminating in an array, the obtained hollow fiber membrane
Not only has high water permeability, but also
The decrease in water performance is extremely small. In the present invention, each of the outer surface side and the hollow surface side
Surface treated with silicone oil mixed in microporous layer
The difference in the average particle size of the inorganic filler
There is no particular limitation as long as it becomes clear. Therefore, before
Average particle size of the inorganic filler used in the present invention described above
Used in each layer by appropriately combining from among
May be set arbitrarily. The resulting multilayer microporous hollow
Considering the effect of maintaining the permeability of the yarn membrane, the hollow surface side
Particles used on the outer surface side compared to those used for
When the diameter ratio is in the range of 1.2 to 50, preferably 1.5 to 5,
Preferably, there is. In the present invention, the layer on the hollow surface side
The average particle diameter of the above-mentioned inorganic filler used for 0.1 to 2 μm
Of the inorganic filler used on the outer surface side
Most preferably, the average particle size is in the range of 0.2 to 5 μm.
New On the other hand, it is formed on the microporous layer on the outer surface side.
The difference between the average pore diameter of the communication hole and that of the outer surface side is also
Although not particularly limited, the hollow surface side is the same as above.
Of the outer surface side to the average pore diameter of
0, preferably 1.5 to 5.
In the present invention, the communication holes formed in the layer on the hollow surface side
The average pore size is in the range of 0.05-0.5 μm, while
The average pore size of the communication holes formed in the layer on the outer surface side is 0.07
Most preferably, it is in the range of 1.5 μm. The multilayer microporous hollow fiber membrane of the present invention comprises
In general, the porosity is preferably 10 to 90%.
Suitable. The outer diameter and thickness of the multilayer microporous hollow fiber membrane
Is not particularly limited. Generally, the outer diameter is 50μ
m to 5 mm, film thickness 10 μm to 0.5 mm
It is preferred that In addition, each microporous laminated
The thickness ratio of the layers is not particularly limited, either, and
You just have to choose. Generally, the layer on the hollow surface side and the layer on the outer surface side
The thickness ratio of the layers is in the range of 1: 0.05 to 1:95.
Is preferred. It should be noted that the multilayer microporous hollow fiber membrane of the present invention
And the average hole diameter of the communication holes laminated on the outer surface side is large
The microporous layer is further provided with communication holes on its outer surface side.
One or more microporous layers with large average pore size
May be layered. Also, the average hole diameter of the communication holes on the inner surface side is small.
On the further inner surface side of the layer, the average pore size of the communication holes of the layer
One microporous layer having communicating holes with an average pore size larger than
Layers or more can be stacked as needed
Can be implemented. The multilayer microporous medium of the present invention having the above constitution
The hollow fiber membrane usually has an initial water permeability of 10 to 70 l / min.
・ M^Two ・ Atm range, 20-70 l / min
・ M^Two ・ It can be atm. Also long-term use
The decrease in water permeability due to clogging is small even in
For example, after treating 4 tons of clean water, the permeability of clean water is usually 4
~ 30 l / min.m^Two ・ Atm range, and 6 ~
30 l / min.m^Two ・ It can be atm. Further, the multilayer microporous hollow fiber membrane of the present invention
Usually has a water pressure resistance of 10,000 to 50,000 mm
H_TwoProperties that extend to O can also be provided. But
Meanwhile, a hydrophobic microporous medium having the above water pressure resistance
In cases where the hollow fiber membrane is disadvantageous, the water pressure is easily reduced.
Almost 0mmH_TwoO can be changed.
For example, the above-mentioned hydrophobic multilayer microporous hollow fiber membrane is
A small amount of a nonionic surfactant of 10 to 23, for example,
Immerse in a solution containing 1-3% water, ethanol, etc.
Or the above surfactant is used to form a multi-layer microporous hollow fiber membrane.
By adding to the material in advance and molding
The water pressure resistance can be reduced. In the present invention, the multi-layer fine
The porous hollow fiber membrane may be manufactured by any method.
Generally, the above-mentioned polyolefin and silicone oil
Inorganic filler surface-treated with
A mixture of two kinds of inorganic fillers having different average particle diameters is often used.
The extruder for hollow fiber production equipped with a layer hollow nozzle
Among the mixtures, those with a large average particle size of the inorganic filler
Fusing so that small ones are stacked on the hollow side
Hollow spinning produces an undrawn hollow fiber membrane having a multilayer structure,
It is preferable to obtain the unstretched hollow fiber membrane by a stretching method.
Suitable. At this time, the above-mentioned inorganic filler is added to the polyolefin.
It is difficult to mix a large amount and uniformly
In such cases, such as polyolefins
A specific amount of dispersant when mixing inorganic fillers
Is preferred. That is, the polyolefin and silicone
100 weight of inorganic filler surface-treated with oil
Add 0.1 to 20 parts by weight of a dispersant to
Is preferable for obtaining each microporous layer having a uniform pore size.
Good. The dispersant is added as a plasticizer to various synthetic resins.
Known compounds to be added can be used without particular limitation. General
The dispersant preferably used is a polyester plasticizer,
Epoxy plasticizer and terminal OH-modified polybutadiene
You. These are exemplified as follows. The polyester plasticizer is generally a carbon atom.
Dibasic acid or tribasic having linear or aromatic ring of number 4 to 8
Acid and a linear dihydric alcohol having 2 to 5 carbon atoms
Those subjected to a tellurization reaction are preferred. Particularly preferably used
Specific examples include sebacic acid, adipine
Acid, phthalic acid, azelaic acid and trimellitic acid
Dibasic acid or tribasic acid, ethylene glycol,
Propylene glycol, butylene glycol, neo
Pentyl glycol and long chain alkylene glycol
Polyester compound, especially adipic acid
Or sebacic acid and propylene glycol, butylene
Glycol or long chain alkylene glycol
Polyester compounds are preferably used. The epoxy plasticizer has 8 to 24 carbon atoms.
Epoxidized double bond of monobasic linear unsaturated acid
Is preferred. The ones that are particularly preferably used
Epoxidized soybean oil, epoxidized linseed oil, etc.
These can be used alone or in combination. [0034] The polybutadiene having an OH end is generally used.
Of polybutadiene having a degree of polymerization of 100 to 10,000
OH end, considering dispersion performance and easy handling
If the degree of polymerization is 500 to 2,000,
Can be used. In mixing each of the above components, the desired multilayer
Disperse as long as it does not hinder production of microporous hollow fiber membrane
Agents, coloring agents, lubricants, antioxidants, anti-deterioration agents, hydrophilization
It is often the case that known additives such as
This is a good mode. The stretching of the undrawn hollow fiber membrane is particularly restricted.
Although not always performed, usually 1.5 to 30 in area magnification
It is preferable to stretch the film in the range of twice. Also, not necessarily two axes
It is not necessary to be stretched in one direction, only in one axis direction
Even with this, it is possible to obtain a hollow fiber membrane with sufficiently good properties.
Wear. Stretching only in the uniaxial direction (the longitudinal direction of the hollow fiber)
In this case, generally 1.5 times to 12 times, preferably 3 to 7 times
Is preferred. It is also stretched biaxially
In this case, preferably 1.2 times or more in the longitudinal direction of the hollow fiber,
1.5 times or more and 1.5 times or more in the circumferential direction of the hollow fiber
Elongation is preferred, and most preferably 2 to 2 in the longitudinal direction of the hollow fiber.
5 times and 2 to 7 times in the circumferential direction of the hollow fiber
Is preferred. The stretching method is generally performed by two pairs of flannels.
Uniaxial stretching due to the difference in the rotation speed ratio of a son roll, etc.
Or, if necessary, after uniaxial stretching, then known widening stretching
Machine to stretch horizontally or vertically and horizontally
And a method of simultaneously stretching. The stretching temperature is generally
Above room temperature to below the melting point of the polyolefin, especially the melting point
A temperature lower by 10 to 100 ° C. is preferred. The microporous medium obtained by stretching
The hollow fiber membrane is further heat-treated under tension, for example, at the temperature of the stretching.
Heat set at a temperature not less than the melting point and then cooled to room temperature
Instead, it is preferable to use the target. In addition, the adhesive
Corona discharge treatment, hydrophilization treatment or
Performing a surface treatment by hydration is a preferred embodiment.
You. The multilayer microporous hollow produced according to the present invention
In the yarn membrane, the polyolefin is molecularly oriented by stretching,
Or, if necessary, by heat setting, hollow
The heat resistance of the yarn membrane itself has been significantly improved, and the mechanical strength has also been improved.
Be improved. In particular, those that have been heat set
The dimensional stability at warm is also significantly improved. [0040] The multilayer microporous hollow fiber membrane of the present invention has
The material is polyolefin homopolymer or olefin and other
Made of copolymerizable monomer, rich in olefin
Good heat resistance, strength, chemical resistance, biocompatibility
The physical properties such as are excellent. The manufacturing method is simple
It is. Furthermore, the inorganic filler contained in the hollow fiber membrane is resistant to
Obtained because it is an insoluble and infusible filler rich in heat
High reliability when using hollow fiber membranes
If there is no trouble that the filler elutes during substance separation
It has the feature of. Moreover, the inorganic filler is silicone
Due to the surface treatment with oil,
The microporous hollow fiber membrane has a large initial water permeability and a long
Even if it is used, the reduction in water permeability is small. General
In addition, the initial water permeability is 10 to 70 l / min · m^Two ・ Atm
Range and large, and 20-70 l / min.m^Two ・ Atm
It can also be. Also, for example, treating 4 tons of clean water
Of permeated water after washing is usually 4 to 30 l / min.m^Two ・
atm, and 6 to 30 l / min · m^Two ・ A
tm. Therefore, the fine particles obtained by the present invention
Porous hollow fiber membranes can be used as filtration membranes for a long time.
is there. Accordingly, the multilayer microporous hollow fiber membrane of the present invention
Can be used as a household water purifier, dust and bacteria
Filter for gas; gas separation membrane; wastewater treatment; food
Clean water in the wares, electronics and pharmaceutical industries
-Manufacture; blood purification, artificial lung, dialysis membrane, etc. in the medical field
Can be used for microfiltration, ultrafiltration, reverse osmosis membrane,
Suitable for use as a support such as evaporation
Is done. [0042] EXAMPLES The present invention will now be described in more detail with reference to the following examples.
The present invention will be described with reference to examples and comparative examples.
It is not limited to the embodiment. Incidentally, the examples and ratios
The physical properties and judgment of the hollow fiber membranes shown in the comparative examples were determined by the following methods.
Indicates the value measured or determined. The maximum pore diameter (μ) of the communicating hole of each microporous layer
m) and average pore size (μm);
A mixture having the same composition as each microporous layer to be formed is
Melt hollow spinning under the same conditions as multilayer microporous hollow fiber membrane
It is further stretched to have the same thickness as the multilayer microporous hollow fiber membrane.
A single-layer microporous hollow fiber membrane was separately produced. Then,
Pore diameter and average of each single-layer microporous hollow fiber membrane
Pore size, maximum pore size in methanol bubble point method
And the average pore size is measured with a mercury porosimeter.
The obtained values are combined with the above-mentioned multilayer microporous hollow fiber membrane.
Maximum pore diameter and average pore diameter of each microporous layer to be formed
did. Water permeability: 10 microporous hollow fiber membranes
Bundled in a U-shape and the hollow fiber membrane opening is fixed with epoxy resin.
Therefore, a module was manufactured. Hollow fiber excluding resin embedded part
The effective length was 15 cm. When measuring water permeability, HL
2% ethanol solution of nonionic surfactant with B = 21
After immersing the module in
Then, the amount of water passing through the wall surface of the hollow fiber membrane was determined. Membrane area
Was based on (outer diameter + inner diameter) / 2 base. First permeability test
Is the initial amount of water permeated for 3 minutes, and 4 tons of clean water
Is shown in the table as the permeation amount of 4 tons.
Was. Moldability: Visually and manually check the undrawn hollow fiber membrane
And touched to observe, and judged according to the following criteria. Good: Uneven thickness and no surface irregularities
state. Slightly good; one of uneven thickness and uneven surface
There is a small state. Poor: uneven thickness, uneven surface
Some state. Dispersibility: The hollow fiber membrane obtained by drawing was
To see if there is a fisheye
  Was. Good; no fish eyes. Poor; fish eye observed
state. Stretchability: The length of the unstretched hollow fiber membrane is
Judgment was made based on the stretching state when stretching in the hand direction. Good; no cutting or tearing, and stretching
The state where it is performed uniformly. Somewhat poor; stretched, but partially unstretched
The state where the part exists. Stretching was not possible; cutting and tearing occurred and stretching was not possible.
Not coming. Examples 1 to 7 and Comparative Examples 1 to 5 Inorganic fillers and silicone oils as shown in Tables 1 and 3
And into the supermixer, 1,500 rpm
After stirring at high speed for 3 minutes, a hot air circulating thermostat at 200 ° C
Heat treatment for 2 hours in silicone oil
The treated inorganic filler was used. Next, surface treatment is performed with this silicone oil.
Inorganic filler and resin as shown in Tables 1 and 3,
Mix the powder composition with a super mixer for 5 minutes
And then extruded into a strand at 230 ° C with a twin-screw extruder
And cut into pellets. The resulting pellets are
Attached to an extruder with a Lew diameter of 20 mmφ and L / D = 22
2 for hollow fiber production with a gas supply pipe of 0.9 mm diameter
Layer nozzleAnd shown in the column of hollow side layer in Tables 1 and 3.
The composition is changed from the inner nozzle of the two-layer nozzle to the outer surface layer.
From the outer nozzle of the two-layer nozzle,23
Extrude at 0 ° C and put into a water tank where water at about 20 ° C circulates
Let cool down and pick up at 13m / minMore than two layersUnstretched
A hollow fiber was obtained. The undrawn hollow fiber-shaped material is rotated at a different rotational speed.
Stretch ratio 5 times at 120 ° C between two pairs of Nelson rolls
To obtain a microporous hollow fiber membrane. The fines obtained
The physical properties of the porous hollow fiber membrane are shown in Tables 2 and 4. The used resin, inorganic filler, silicone
The following products were used as the oil and dispersant. Resin; Polypropylene; PN-120 (trade name, manufactured by Tokuyama Soda Co., Ltd.)
Product name) Density 0.91g / cm^Three , 135 ° C tetralin
2.38 dl / g, melting point 165 ° C. Polyethylene; Mitsui Petrochemical Industry Co., Ltd.
Made, high density polyethylene, HIZEX 1300J (Trade
Product name), melt index 1.3g / 10min. Propylene-ethylene copolymer; Soda Tokuyama
MS-624 (trade name), 0.90 g /
cm^Three1. intrinsic viscosity measured with tetralin at 135 ° C.
28 dl / g, melting point 163 ° C, ethylene content 4.7
amount%. Inorganic fillers; Calcium carbonate; Viscolite U, manufactured by Shiroishi Industry Co., Ltd.
(Trade name), average particle size 0.09 μm. Tunex E (trade name), average particle size 0.5
μm. White, manufactured by Toyo Fine Chemical Co., Ltd.
PO (trade name), average particle size 1.05 μm. Whiten P-, manufactured by Shiraishi Calcium Co., Ltd.
10 (trade name), average particle diameter 3.0 μm. Talc; 850J manufactured by Nippon Sumitron Co., Ltd.
S (trade name), average particle size 2.0 μm. Anhydrous aluminum silicate; calcium shiraishi
TYSIN (trade name), average particle size 0.8μ
m. Aluminum hydroxide; Showa Light Metal Co., Ltd.
Manufactured by Hydride (trade name), average particle size 6 μm. Silicone oil; Dow Corning Toray
SH-200 (trade name), molecular weight 10,000 Chemical structure; polydimethylsiloxane (OSi (CH_Three)_Two
 O)_n SH-510 (product of Dow Corning Toray Co., Ltd.)
Name), molecular weight 15,000 Chemical structure; polymethylphenylsiloxane (OSiCH
_ThreeC₆H_FiveO)_n Dispersant: Nippon Soda Co., Ltd., OH-terminated polybutadier
GI-1000 (trade name). [0070] [Table 1][0071] [Table 2][0072] [Table 3][0073] [Table 4]Comparative Example 6 Attached to an extruder with a screw diameter of 20 mmφ and L / D = 22
Manufacture of hollow fiber with a gas supply pipe with a diameter of 0.9 mmφ
The melt index is 34 g /
10 minutes polypropylene (MJ-1 manufactured by Tokuyama Soda Co., Ltd.)
70 (trade name)) and the melt index
Is 4.4 g / 10 min polypropylene (Tokuyama Soda Co., Ltd.)
, Made of YE-130 (trade name))
A hollow fiber membrane was manufactured. The conditions for melt hollow spinning are extrusion
The temperature is 200 ° C and the take-off speed is 116m / min.
Was. The obtained undrawn hollow fiber membrane is placed in an air atmosphere at 145 ° C.
Heat treatment for 5 minutes, then roll in liquid nitrogen at -195 ° C.
Uniaxially stretched to an elongation ratio of 2 and then stretched
Heat treatment at 145 ° C for 15 minutes as it is
A membrane was manufactured. This microporous hollow fiber membrane has an outer surface side layer
It has a multilayer structure of 80 μm and a hollow side layer of 20 μm.
The average pore size of the communication holes formed in the microporous layer on the outer surface side
The diameter is 1.5 μm, and the average pore diameter on the hollow surface side is 0.5 μm.
μm. The initial water permeability of this microporous hollow fiber membrane was 4 to
When the water permeability was measured, the initial water permeability was 35 l / min.
m^Two ・ Atm, 4 tons permeation rate is 4.3 l / min ・ m
^Two -It was atm.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI D01F 8/06 D01F 8/06 (58) Investigated field (Int.Cl. ⁷ , DB name) B01D 69/08 B01D 71/26

Claims (1)

(57) [Claim 1] 10 to 70% by weight of a polyolefin, and an average particle size dispersed in the polyolefin of 0.01%.
A two-layer microstructure having a network structure composed of 90 to 30% by weight of an inorganic filler surface-treated with a silicone oil having a maximum pore diameter of 5 μm or less and having a molecular orientation by stretching. It is constituted by laminating a porous layer,
The two layers differ in the average particle diameter of the inorganic filler and the average pore diameter of the communication holes, and the layer having the larger average particle diameter of the inorganic filler and the average pore diameter of the communication holes is located on the outer surface side, and the smaller layer is A multilayer microporous hollow fiber membrane located on the hollow surface side.