JPH01288302A - Microporous hollow fiber membrane and its manufacturing method - Google Patents

Abstract

PURPOSE:To obtain hollow fiber membranes which can be easily produced at low cost by mixing inorganic fillers into the melted polyolefins, forming the mixture into a hollow-shape to be drawn. CONSTITUTION:Polypropylene at a ratio of 20-80wt.%, inorganic fillers composed of calcium carbonates having a mean particle diameter of 0.01-5mum at a ratio of 80-20wt.%, and plasticizer such as adipic acid polyester etc. are mixed so that the mixture thus obtained is melt-molded into hollow-shaped articles by means of an extruder etc. provided with a double-cylinder-type mouth piece for use in manufacturing hollow fiber membrane, following which the hollow- shaped articles are drawn at an area magnification ratio of 1.5-30. In this manner, micro-porous hollow fiber membranes, which have been molecular-oriented by application of drawing and have a netlike structure composed of communicating pores having a maximum pore diameter of 5mum or less and a void ratio of 20-90%, are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a microporous hollow fiber membrane made of polyolefin containing a filler having a specific particle size, and a method for producing the same.

(Problems to be solved by conventional techniques and inventions) In recent years,
Separation methods using hollow fiber membranes have rapidly come into use on a practical scale from the viewpoints of resource saving, energy saving, separation and purification, etc. Many polymeric materials have been studied as materials for membranes used in such membrane separation methods, and for example, polymeric materials such as cellulose ester, polyolefin, and polysulfone have been proposed. It goes without saying that the materials used in membrane separation methods must have excellent separation performance, as well as other properties such as mechanical properties that can withstand the conditions of use, chemical resistance, and biocompatibility. Furthermore, it is also an important requirement that the membrane be easily manufactured at low cost.

Among the many technologies for membrane materials that have been proposed in the past, there has been no hollow fiber membrane that can satisfy all of these characteristics. for example,
Cellulose ester-based and polysulfone-based hollow fiber membranes used for reverse osmosis, ultrafiltration, gas separation, etc. are formed by extruding a solution dissolved in a solvent through a double tube mouthpiece and introducing it into a coagulating liquid to form a film. It is obtained by a so-called wet phase separation method. These hollow fiber membranes are easy to form and have excellent permeation performance, but in addition to lacking chemical resistance, they also have poor mechanical strength, especially breaking strength and breaking elongation, and are helical or U-shaped. There is a problem in that when the hollow fiber membrane is assembled into a module, it tends to break easily and the excellent mechanical properties of the material are lost.

On the other hand, after forming a thermoplastic crystalline polymer material, such as polyolefin or polyvinylidene fluoride, into a hollow fiber, this is heat-treated and then stretched and heat-treated to generate pores in the peripheral wall of the hollow fiber. The so-called dry process, which utilizes methods to produce porous bodies, has also become common.

However, in the conventional method as described above, in order to improve the quality of the obtained porous hollow fiber, it is common to add an operation to increase the crystal orientation of the undrawn hollow fiber in advance, and therefore, it is still There have been problems in that the manufacturing process of the porous hollow fibers as a whole tends to be complicated, resulting in high costs, and furthermore, the diameter of the hollow fibers and the membrane thickness cannot be increased.

Other manufacturing methods for hollow fiber membranes include JP-A No. 61-90707
As shown in the publication, organic fillers made of hydrocarbons such as liquid paraffin and oligomers are kneaded with polymers, and after melt molding, the organic fillers are extracted with alcohols, halogenated carbon hydrogens, etc. One method is to do so. However, in the method of simply filling a polymer with such an organic filler and extracting it, the structure of the pores formed tends to be independent single pores.

Therefore, in order to substantially form a large number of communicating pores, it is necessary to increase the amount of filler added, and if this is done, the viscosity becomes too low due to the large amount of filling, making it difficult to form into hollow shapes. The resulting porous hollow fiber membrane had a low porosity.

The present inventors have provided the above-mentioned hollow fiber membrane with the required characteristics,
The aim is to develop a new hollow fiber membrane that can be easily molded at low cost.It has excellent separation and permeability, does not lose the original excellent chemical resistance and mechanical strength of polyolefin, and is low cost. We have conducted intensive research on hollow fiber membranes that can be easily produced. As a result, the present inventors discovered that a hollow fiber membrane obtained by melt-mixing a filler with a polyolefin, forming a hollow membrane, and stretching the membrane satisfies all of the above objects, thereby completing the present invention.

That is, the present invention comprises 20 to 80% by weight of polyolefin,
The average particle diameter dispersed in the polyolefin is 0.01
It consists of 80 to 20% by weight of a filler with a diameter of ~5 μm, and has a rod-like structure consisting of communicating pores with a maximum pore diameter of 5 μm or less,
It is a microporous hollow fiber membrane having a porosity of 20 to 90% and molecularly oriented by stretching.

The microporous hollow fiber membrane of the present invention mainly consists of a polyolefin and a filler dispersed in the polyolefin.

Examples of the polyolefin include homopolymers of α-olefins such as polyethylene, polypropylene, polybutene-1, or polymethylpentene, copolymers of α-olefins with other copolymerizable monomers, and mixtures thereof.

Among these, in consideration of the heat resistance and moldability of the microporous hollow fiber membrane of the present invention, propylene homopolymers, copolymers of propylene and other copolymerizable monomers, and mixtures thereof are preferred.

The copolymer of the above α-olefin and other copolymerizable monomer generally contains 90% or more of α-olefin, particularly propylene, and 10% or more of other copolymerizable monomer.
Copolymers containing up to % by weight are preferred. Further, the copolymerizable monomer is not particularly limited, and known monomers can be used, but α-olefins having 2 to 8 carbon atoms, particularly ethylene and butene, are generally preferred.

In the present invention, the filler dispersed in the polyolefin is one that is substantially stable under the melting conditions of the polyolefin, for example, at a temperature of 100° C. above the melting point of the polyolefin, and does not react with the polyolefin. Further, it is preferable that when mixed with polyolefin, it does not agglomerate and is uniformly dispersed. The filler is used in the stretching process to cause peeling at the interface between the polyolefin and the dispersed filler to form fine communicating pores.

The filler used in the present invention is not particularly limited as long as it exhibits the above-mentioned function, but in particular filler selected from the group consisting of group mA, group 1IIA, and group 1VB of the periodic table. Non-siliceous fillers consisting of oxides, hydroxides, carbonates, or sulfates of certain metals are preferred. These fillers are not particularly limited and may be those known as fillers for various synthetic resins, but examples of fillers suitably used for -a are as follows. Group metals include alkaline earth metals such as calcium, magnesium, and barium; Group A metals include boron and aluminum; and Group VI metals such as boron and aluminum.
As the B group metal, metals such as titanium, zirconium, and hafnium are suitable. Oxides, hydroxides, carbonates, or sulfates of these metals can be used without particular limitation. More specific examples of fillers that are particularly preferably used include oxides such as calcium oxide, magnesium oxide, barium oxide, aluminum oxide, boron oxide, titanium oxide, and zirconium oxide; calcium carbonate, magnesium carbonate,
Carbonates such as barium carbonate; hydroxides such as magnesium hydroxide, calcium hydroxide, and aluminum hydroxide; sulfates such as calcium sulfate, barium sulfate, and aluminum sulfate.

The average particle diameter of the above filler needs to be 0.01 to 5 μm. If the average particle size of the filler is outside the above range, it may become difficult to disperse the filler into polyolefin, or the maximum pore size may be too large, making it difficult to perform reverse osmosis, ultrafiltration, gas separation, etc. It cannot be used for this purpose. In order to obtain a porous hollow fiber membrane suitable for such uses,
The average particle diameter of the filler is preferably 0.03 to 3 μm.

The above-mentioned polyolefin (a) and an average particle diameter of 0.01
The ratio of (a) to filler ('b) which is ~5 μm is 2
0-80% by weight, preferably 30-? OfE view%, (
b) is 80-20% by weight, preferably 70-30% by weight
It is.

The compositional ratio of the components (a) and (b) is important for maintaining the properties of the microporous hollow fiber membrane within the specified range and industrially advantageously producing the microporous hollow fiber membrane. . (b)
If the proportion of the components is less than the lower limit, the resulting microporous hollow fiber membrane will not have sufficient pore formation, making it impossible to obtain the desired porosity. On the other hand, if the proportion of component (b) added exceeds the above upper limit, the formability of the hollow fiber membrane tends to deteriorate, stretching cannot be performed sufficiently, and a sufficient porosity cannot be imparted, so this is not preferable. do not have.

The microporous hollow fiber membrane of the present invention forms a network structure consisting of communicating pores with a maximum pore diameter of 5 μm or less, and has a porosity of 20 μm or less.
-90% preferably 35-80%.

The pores of the microporous hollow fiber membrane of the present invention are small and have excellent uniformity, and the average pore diameter is generally in the range of 0,000 to 2 μm. In addition, the amount of nitrogen gas permeated is -100%
~100.000j! /rd-hr-0,5a
te range, and further 1000 to 100.0001
/ld・hr・0.5ats can also be used.

The small average pore diameter and excellent uniformity and the large porosity have a close relationship with the above-mentioned preferred amount of nitrogen gas permeation. Further, the amount of nitrogen gas permeated has a close relationship with the water permeability of the hollow fiber membrane of the present invention, and generally has a value of 1 to 1000 It/n(·hr-atII).

Since the maximum pore diameter and porosity mentioned above are properties that are related to each other, it is not necessarily appropriate to list defects when these upper and lower limits are exceeded independently, but -
The following can be said about boat fishing.

When the maximum pore diameter exceeds 5 μm, the amount of nitrogen gas permeated and the amount of water permeated often exhibit permeation performance exceeding the above upper limit, but liquid/solid, liquid/gas, liquid/liquid, This is not a preferred embodiment because it also reduces the gas/solid separation performance. On the other hand, the maximum pore diameter is 0.0
If it is smaller than 1 μm, the separation performance is excellent, but the amount of nitrogen gas permeation and the amount of water permeation are significantly reduced, making it unsuitable for practical use. Furthermore, if the porosity is smaller than the lower limit value, there will be a tendency for nitrogen gas permeation performance and water permeability. Conversely, if the porosity is larger than the upper limit value, not only will the strength be weakened, but there is also concern that the separation performance will deteriorate. So I don't like it. Further, since the upper limit value of the porosity is affected by the amount of filler blended in the manufacturing method described later, it is not a good idea to obtain a material exceeding the above upper limit value from an industrial manufacturing method.

Furthermore, the microporous hollow fiber membrane of the present invention can be provided with properties that normally have a water pressure resistance of 10,000"'50,000 mHz. However, hydrophobic microporous membranes that have the above water pressure resistance In cases where hollow fiber membranes are disadvantageous, the water pressure resistance can be easily reduced, and Habo-O-Tsuru H!0
It can be changed to. For example, the hydrophobic microporous hollow fiber membrane may be immersed in an aqueous solution containing a small amount, for example, 1 to 3%, of a nonionic surfactant with an HLB of 10 to 15; The water pressure resistance can also be reduced by adding it in advance to the material of the microporous hollow fiber membrane and molding it.

In addition to the properties described above, an important element of the microporous hollow fiber membrane of the present invention is that it is stretched. The pores of the microporous hollow fiber membrane are extremely uniform, and as is clear from the explanation of the production method below, this uniformity is produced by stretching polyolefin containing a large amount of filler. be. In order for pores to occur uniformly,
Although the combination of additives for uniformly dispersing the filler in the polyolefin is an important factor, the stretching ratio is also an extremely important factor.

The stretching ratio of the microporous hollow fiber membrane of the present invention is in the range of 1.5 to 30 times in area stretching ratio. The above-mentioned areal stretching ratio does not necessarily have to be biaxially stretched, and a hollow fiber membrane with sufficiently good properties can be obtained even by stretching only in one axis. When stretching only in the uniaxial direction (longitudinal direction of the hollow fiber), it is preferable to stretch the fiber by 1.5 to 12 times, preferably 3 to 7 times, or in two axial directions. In case, 1 in uniaxial direction (longitudinal direction of hollow fiber)
．． Stretching is preferably 2 times or more, preferably 1.5 times or more, and 1.2 times or more, preferably 1.5 times or more in two axial directions (circumferential direction of the hollow fiber), and most preferably 2 to 5 times in one axis direction. Preferably, the film is stretched 2 to 7 times in both the double and biaxial directions.

The microporous hollow fiber membrane of the present invention generally has an outer diameter of 50 μm to
A film having a film thickness of 10 μm to 0.5 μm can be obtained.

In the microporous hollow fiber membrane of the present invention, by stretching the polypropylene containing the filler, pores are generated around the filler, and these pores become pores. The microporous hollow fiber membrane may be used as a target product while containing the filler, or may be used as a target product by extracting the filler as necessary. A known method may be adopted depending on the type of agent. For example, inorganic fillers generally include hydrochloric acid, formic acid,
Extraction may be performed using an acid solution such as acetic acid or a mixed solution of a nucleic acid solution and an alcohol solution such as methanol or ethanol.

In order to obtain the microporous hollow fiber membrane, it is necessary to use specific combinations of types, combinations, and amounts of polyolefins, fillers, and additives. A typical manufacturing method will be explained below.

That is, (11) 20 to 80% by weight of polyolefin, (b
) Filler 80-2 having an average particle diameter of 0.01-5 μm
0% by weight and (c) a plasticizer of 0.1 to 5% by weight based on 100 parts by weight of the total amount of (a) and (b) above is melt-molded into a hollow shape, and then the hollow object In this method, the film is stretched at an area stretching ratio of 1.5 to 30 times.

The above (a) polyolefin, (b) an average particle diameter of 0.
Fillers with a diameter of 01 to 5 μm and these (al component and (b)
) The composition ratios of the components are as described above.

It is difficult to uniformly mix a large amount of component (b) with component (a). In order to eliminate this drawback, it is important to add a specific amount of plasticizer when mixing the components (a) and (b). That is, 0.1 to 5 parts by weight of the plasticizer is added to 100 parts by weight of the total amount of the ta+ component and the middle) component.

The amount of component (c) added has a greater influence on the properties of the microporous hollow fiber membrane than the composition ratio of component (8) and component (b). If the amount of the plasticizer component (c) added is less than the above lower limit, the filler will not be well dispersed and a microporous hollow fiber membrane having uniform pores will not be obtained.

Furthermore, if the amount of component (c) added is greater than the upper limit, the plasticizer will partially flow out during molding of the hollow fiber membrane, making it impossible to control the thickness and diameter of the resulting membrane, resulting in the desired microporous hollow fiber membrane. I can't get it. The plasticizer which is the component (c) is known as a plasticizer added to various synthetic resins, and these known plasticizers can be used without particular limitation.Generally, they are preferably used. The plasticizers used are polyester plasticizers and epoxy plasticizers. Examples of these are as follows.

Polyester plasticizers are generally those obtained by esterifying a dibasic acid or tribasic acid having a linear or aromatic ring having 4 to 8 carbon atoms and a linear dihydric alcohol having 2 to 5 carbon atoms. suitable. Specific examples of those particularly preferably used include sebacic acid, adipic acid, phthalic acid,
A polyester compound consisting of dibasic or tribasic acids such as azelaic acid and trimellitic acid, and ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, long-chain alkylene glycol, etc., especially adipic acid or A polyester compound consisting of sebacic acid and propylene glycol, butylene glycol or long-chain alkylene glycol is preferably used.

The most preferable epoxy plasticizer is one obtained by epoxidizing the double bond of a monobasic linear unsaturated acid having 8 to 24 carbon atoms. Particularly preferred examples include epoxidized soybean oil and epoxidized linseed oil, which can be used alone or in combination.

Furthermore, for the purpose of improving moldability or dispersibility of the component (b), in addition to the component (c), a liquid or waxy hydrocarbon polymer (fd) or a fluorosurfactant (e) may be added. It is also a preferable embodiment to add appropriate amounts of the like as necessary. (The amount of dl component and te+ component added is
0.01 to 10 parts by weight, and further 0.01 to 10 parts by weight, per 100 parts by weight of the total amount of components (a) and (b).
A range of 5 parts by weight is preferred.

The above-mentioned (dl component and (+3) component) are not necessarily essential as additive components, but it is generally preferable to add them within the range of the above-mentioned addition amounts because favorable results can often be obtained. When the amount of the liquid or waxy hydrocarbon polymer added exceeds 10 parts by weight based on 100 parts by weight of the total amount of component (a) and component (bl),
Like the plasticizer, it partially flows out during hollow fiber membrane molding, so it is preferable to limit the amount added to 10 parts by weight or less.

Furthermore, if the amount of component (e) added exceeds the upper limit, gas will be generated during molding of the hollow fiber membrane, making it impossible to control the pore diameter of the microporous hollow fiber membrane.
) The amount of the component added is preferably 10 parts by weight or less.

Component (d) can be used without any particular limitation as long as it is a liquid or waxy hydrocarbon polymer, but in general, saturated or unsaturated hydrocarbon polymers such as polybutadiene, polybutene, and polyisoprene are preferred. , polymers with hydroxyl groups introduced at the ends of these hydrocarbons, and hydrogenated polyhydroxy hydrocarbon polymers can be suitably used.

Furthermore, as the fluorine-based surfactant of the component (e), any known fluorine-containing surfactant can be used without particular limitation. Particularly preferably used are potassium or ammonium salts of alkyl carboxylic acid or alkyl sulfonic acid having 6 to 8 carbon atoms in which some or all of the hydrogen atoms of the alkyl group have been replaced with fluorine atoms. Fluorinated anionic surfactant; Fluorinated cationic surfactant consisting of fluorinated alkyl quaternary ammonium iodide; Fluorinated alkyl carboxylic acid or fluorinated alkyl sulfonic acid and 1 to 4 carbon atoms
These include fluorine-based nonionic surfactants consisting of esters with monohydric or polyhydric alcohols.

Specifically, those that can be used particularly preferably include, for example:
Fluorinated alkyl carboxylic acid ester or fluorinated alkyl sulfonic acid ester of fluorinated alkyl carboxylic acid or fluorinated alkyl sulfonic acid and propyl alcohol, or glycerin; Fluorinated nonionic surfactants such as fluorinated alkyl polyoxyethylene ethanol, etc. can be mentioned.

The mixing of the components (a), (b), (c) and the optionally added components (d) and (e) is not particularly limited, and any known mixing method can be employed. For example, each of the above components can be added and mixed simultaneously to a mixer such as a super mixer, a Henschel mixer, etc., or the above (bl
Component (c), di-acid component and component (e) are mixed in advance, and the polyolefin is melt-kneaded into the mixture using, for example, a spindle or two-screw extractor, and the extrudate is cut into pellets. It is also possible to adopt the method of

When mixing the above components, known additives such as colorants, lubricants, antioxidants, deterioration inhibitors, hydrophilic agents, and hydrophobic agents may be added to the extent that they do not interfere with the production of the desired microporous hollow fiber membrane. Adding is often a good option.

The microporous hollow fiber membrane of the present invention can be obtained by melt-molding the mixed composition into a hollow object and then stretching it.

The method for molding the above composition into a hollow shape is not particularly limited, but generally a hollow fiber can be obtained using a known extruder for producing hollow fibers equipped with a double cylindrical die.

Hollow objects are generally uniaxially stretched using a roll stretching method, or if necessary, after -axial stretching, a method is adopted in which the material is successively stretched in the transverse direction using a known widening stretching machine or the like, or simultaneously in the longitudinal and transverse directions. be done.

After mixing filler with resin and forming it into a sheet or film,
Techniques for stretching porous sheets or film-like materials are widely known, and uniaxial stretching or two-wheel stretching methods have been adopted as methods for stretching such sheets or film-like materials. Opening and porous formation by stretching the sheet or film-like material is practically achieved with a porosity of about 30% in the uniaxial stretching method, and then or simultaneously with the biaxial stretching method.
A porosity of 0% or more was provided.

However, in the microporous hollow fiber membrane of the present invention, a porosity of around 50% can be obtained by simply mixing a filler with a resin, molding it into a hollow object, and then uniaxially stretching it. It has the advantage that the porosity is comparable to that of a stretched two-wheeled product in the case of a so-called flat membrane.

The stretching temperature is generally from room temperature to below the melting point of the polyolefin, preferably 10 to 100°C lower than the melting point.The hollow fiber membrane obtained by the above stretching becomes a microporous hollow fiber membrane having the physical properties as described above. .

Although the microporous hollow fiber membrane obtained by the above method is obtained in a state containing a filler, it can be used as it is for the various uses described above. However, depending on the intended use, if the contamination of fillers reduces or limits the separation and purification functions, it is preferable to extract and remove the fillers by post-treatment. Extraction of the filler can be achieved by immersing the material in an alcohol mixture of hydrochloric acid, formic acid, etc. at a temperature of 10 to 60° C. for 1 hour to 2 days.

The microporous hollow fiber membrane obtained by the stretching or the microporous hollow fiber membrane obtained by extracting the filler from the hollow fiber membrane is further heat-treated under tension, for example, at a temperature above the stretching temperature but below the melting point. It is preferable to heat-set the material at a temperature of is a preferred embodiment.

In the hollow fiber membrane according to the present invention, the polyolefin is molecularly oriented by stretching or further heat-set, so that
The heat resistance of the hollow fiber membrane itself is significantly improved, and the mechanical strength is also improved. In particular, those that have been heat-set have significantly improved dimensional stability both at room temperature and at high temperatures.

As explained above, the microporous hollow fiber membrane of the present invention is made of a polyolefin homopolymer or olefin and other copolymerizable monomers, and is rich in olefins, so it has good heat resistance, strength, It also has excellent physical properties such as chemical resistance and biocompatibility.

Moreover, since the hollow fiber membrane is stretched, it not only has excellent physical properties such as strength, but also has a maximum pore diameter of 5.
A network structure consisting of communicating pores with an average pore size of 0.005 to 2 μm is formed, and the pores are extremely uniform with a porosity of 20 to 90%.

In addition, the N2 gas permeation rate of the hollow fiber membrane is 10” to 10S1/
rd/hr/0.5 atm, which is extremely good.

Therefore, the microporous hollow fiber membrane of the present invention can be used as an air filter for dust removal and sterilization; a gas separation membrane; wastewater treatment; clean water production in the food industry, electronic industry, and pharmaceutical industry; household water purifier; It can be used in the fields of blood purification, artificial lungs, near-separation membranes, etc., and is suitably used as a support for microfiltration, ultrafiltration, reverse osmosis membranes, pervaporation, etc.

- Amount of water permeation: A module was produced by bundling 10 microporous hollow fiber membranes and hardening the openings of the hollow fiber membranes with epoxy resin. The effective length of the hollow fiber excluding the resin-embedded portion was 15c+s. When measuring water permeability, after immersing the module in a 2% ethanol solution of a nonionic surfactant with an HLB of 14.6, 1atII clean water was applied to measure the amount of water passing through the wall of the hollow fiber membrane. I asked for it. The membrane area was based on the inner diameter.

- Formability: The unstretched hollow fiber membrane was visually and manually observed and evaluated using the following criteria.

Good condition; no thickness unevenness or surface irregularities.

Slightly good; There is slight unevenness in thickness or surface unevenness.

Defective: The thickness is uneven and the surface is uneven.

Fist bone dispersion: The hollow fiber membrane obtained by stretching was visually observed and judged by whether or not there was a finch eye.

Good; no fish eyes.

Poor: Condition in which fish eyes are observed.

- Stretchability: Judgment was made based on the stretching state when the unstretched hollow fiber membrane was stretched in the longitudinal direction of the hollow fiber.

Good: No cutting, no curling, and uniform stretching.

Slightly poor: Even if stretching is possible, there are some unstretched parts.

Unable to stretch; cutting and tearing occur and stretching is not possible.

EXAMPLES In order to explain the present invention more specifically, Examples and Comparative Examples will be described below, but the present invention is not limited to these Examples.

Note that the physical properties and evaluations of the hollow fiber membranes shown in Examples and Comparative Examples are values measured or determined by the following methods.

- Maximum pore diameter (μ): Measured by methanol bubble point method.

- Porosity (%): Measured by mercury porosimeter method.

Porosity - (pore volume / porous membrane volume)
The strength and elongation of the hollow fiber membrane at breakage were measured under tension at 0%/+sin.

-Nitrogen gas permeation amount: A module was produced by bundling 10 microporous hollow fiber membranes and solidifying the openings of the hollow fiber membranes with epoxy resin. Effective length of hollow fiber excluding resin embedded part is 150II
And so. Q, 5a is applied to this module hollow fiber membrane with Nz gas.
N passes through the wall of the hollow fiber membrane under a pressure of tm at 25°C.

The amount of gas was determined. The membrane area was based on the inner diameter.

Examples 1 to 18 and Comparative Examples 1 to 3 A resin, a filler, a plasticizer, a liquid or waxy hydrocarbon polymer, and a fluorosurfactant as shown in Table 1 were combined into a mixture of the resin and filler. 0.0% for each 100 parts by weight of the total amount.
A composition consisting of 1 part by weight was mixed for 5 minutes using a super mixer, then extruded into a strand at 210°C using a twin-screw extruder, and cut into pellets.

The obtained pellet was screwed with a screw diameter of 40 φ, L/D=
It was extruded at 230°C from a hollow fiber production nozzle with a double tube structure with a diameter of 4H attached to an extruder of 22, and cooled by putting it into a water tank in which water at about 20°C circulated.
It was taken off at a speed of 0.00 m/min to obtain an undrawn hollow fiber material.

This unstretched hollow fiber material was uniaxially stretched at 110° C. at a stretching ratio of 4.5 times between two pairs of Nelson rolls having different rotation speeds to obtain a microporous hollow fiber membrane.

Table 1 shows the physical properties of the microporous hollow fiber membrane obtained.

The resins, fillers, plasticizers, liquid or waxy hydrocarbon polymers, and fluorosurfactants used were the products listed below.

Polypropylene: Tokuyama Soda special product, PN-120 (trade name) Density: 0.91 g/cx3° Measured with tetralin at 135°C, Intrinsic viscosity: 2.38 d1/g, Melting point: 166°C.

Propylene-ethylene copolymer; Tokuyama Soda special product, MS-624 (trade name) density 0.90 g/cra".

Measured with Tetralin at 135℃ Intrinsic viscosity 2.28d17g, melting point 163℃, contains ethylene! 4.7 weight%.

Polyethylene: manufactured by Mitsui Petrochemical Industries, high-density polyethylene, HIZEX 1300J (trade name), melt index 1.3 g/10 minutes.

Calcium carbonate: Shiraishi calcium side type, average particle size 0.
08. cz (7) Hakureika CCR (product name), Hakuenka O (product name) with an average particle size of 0.03μ, Wheaton 5SB (red) with an average particle size of 1.2μ, and Whiten P-10 (product name) with an average particle size of 3μ given name).

Aluminum hydroxide; Specially manufactured by Showa Light Metal, average particle size 6μ
, Hysilide H-32 (Product name) Plasticizer; Adipic acid polyester - manufactured by Dainippon Ink Chemical Co., Ltd., Polysizer W2300 (Product name) Liquid waxy hydrocarbon polymer; Produced by Nippon Soda Co., Ltd., terminal hydroxylated polybutadiene G1-1000 ( (Product name) Fluorinated surfactant; Fluorinated alkyl ester; Fluorad FC-430 (trade name), manufactured by Jujutsu 3M Co., Ltd. Comparative Example 4 In the same manner as in Example 1, a composition consisting of a resin, a filler, a plasticizer, and others was used. After mixing in a super mixer for 5 minutes, the mixture was extruded into a strand at 210°C using a twin screw extruder and cut into pellets.

The obtained pellet was screwed with a screw diameter of 3011φ and L/D.
= Extruded at 230℃ from a lip gap attached to a 24 extruder with a diameter of 1 where water at 60℃ circulates inside.
Glued to cooling roll of 00flφ, take-off speed 0.8
A sheet was obtained at m/min.

This sheet-like material was uniaxially stretched at a stretching ratio of 4.5 times at 110° C. between two pairs of heated embroider rolls having different rotation speeds.

Table 1 shows the physical properties of the obtained uniaxially stretched porous film.

Examples 19 to 36 Microporous hollow fiber membranes containing the filler obtained in each example shown in Table 1 were heated in 12N HC1/methanol (
Volume ratio = 50150) was immersed for 24 hours to extract the contained filler. As a result, the physical properties of the microporous hollow fiber membrane obtained were as shown in Table 2.

Procedural amendment June 24, 1988 Director General of the Patent Office Yoshi 1) Takeshi Moon 1, Indication of the case 1988 Patent Application No. 116977-2, Name of the invention Microporous hollow fiber membrane and its manufacturing method 3, 1.Relationship with the person making the correction Patent applicant address: 1-1-4, Mikage-cho, Tokuyama-shi, Yamaguchi Prefecture Date of amendment order: Voluntary action: 5 Number of claims increased by amendment: None 6: M-correct subject specification The scope of claims in the "Claims" and "Detailed Description of the Invention" are amended as shown in the attached sheet.

(2) Page 2, line 12; page 5, line 14, 20
Line; page 6, line 6; page 7, line 5, line 10, 1
1st line, 14th line, 19th line, 20th line; same page 8 lO
Lines, 18th, 19th, 20th; 9th page, 4th line, 8th line; 11th page, line 16; 12th page, line 16;
Line 18; page 13, lines 19 and 20; page 14, line 2, line 3, line 4, line 5, line 11, line 15; page 15, line 1 2nd page, line 12; same page 20, line 20;
Page 21, line 10; Page 21, line 20 to page 22, line 1; Page 22, line 3, line 5, line 6, between line IO, page 26, line 17 page 27, line 15; page 29, line 14; page 31, table 1; page 32
On the 2nd and 5th lines of the page, correct "filler" to "inorganic filler".

(3) Page 5, line 4, Correct "filler" to "organic filler".

(4) On page 11, line 13, "there is a tendency for water permeability" to be amended to "there is a tendency for water permeability to decrease."

(5) Page 12, line 7, Correct 1"1O-15J to "10-23".

(6) On page 12, line 8, "immersion in an aqueous solution" is corrected to "immersion in an aqueous or alcoholic solution."

(7) Same page 24, line 4 to page 25, line 11, ``・Amount of water permeation; 10 microporous hollow fibers...(omitted)...
・Unable to stretch; Delete "state where stretching is not possible due to cutting or tearing."

(8) On page 25, line 17, after “indicate.” “However, the maximum pore diameter, porosity, nitrogen gas permeation amount, and water permeation amount are for the membrane portion excluding the hollow portion of the hollow fiber membrane. Insert "It is a physical property."

(9) On page 26, lines 14 to 15, after “Based on the inner diameter”, insert a new line and add “・Amount of water permeation; 11,110 microporous hollow fibers are bundled to form a hollow fiber M#11. The entire mouth part was solidified with xy resin to prepare a module.The effective length of the hollow fiber excluding the resin-embedded part was 15'Cl11.When measuring water permeability,
After the module was immersed in a 2% ethanol solution of a nonionic surfactant with HXrB of 14.6, latm clean water was poured over it, and the amount of water passing through the wall of the hollow fiber membrane was determined. The membrane area was based on the inner diameter.

- Formability: The unstretched hollow fiber membrane was visually and manually observed and judged according to the following criteria.

Good: No thickness unevenness or surface irregularities situation.

Fairly good i: Thickness unevenness or surface depressions A state in which one side of the convexity is slightly convex.

Defective: There is uneven thickness and dents on the surface. A state where there is a convexity.

- Dispersibility: The hollow fiber membrane obtained by stretching was visually inspected and judged by the presence or absence of fish eyes.

Good; no fish eyes.

Defective; fish eyes observed state.

- Stretchability: Judgment was made based on the stretching state when stretching the hollow fiber in the longitudinal direction of the unstretched hollow fiber membrane.

Good; no cutting or tearing, stretching is being performed uniformly.

Slightly poor: Even if stretching is possible, some parts A state in which an unstretched portion exists.

Unable to stretch; cutting and tearing occur Unable to stretch. " of insert.

Claims after the above amendment: ``(1) Polyoleain 20~sod!ig and an average particle diameter of 0.01~sod!ig dispersed in the polyoleain.
It is composed of 80 to 20% by weight of a filler with a diameter of 5μ, has a network structure consisting of continuous pores with a maximum pore diameter of 5μ or less, has a porosity of 20 to 90%, and can be stretched to form a polymolecular material. Oriented microporous hollow fiber membrane.

(2) (-giri olefin 20-80 weight-(b)
Inorganic filler 80 with an average particle diameter of 0.01 to 5μ
~20wt 11% (c) The plasticizer is the total amount of the above (Q and (b) Zoo
A mixture consisting of 0.1 to 5 parts by weight based on the amount of heavy weight cotton is melt-molded into a hollow shape, and then the hollow shape is stretched at an area stretching ratio of 1.
．． A method for producing a microporous hollow fiber membrane, which comprises stretching 5 to 30 times.

(3) From the microporous hollow fiber membrane described in claim (1)! ! Microporous hollow fiber membrane with filler removed.

(4) (a) Polyolefin 20-80j1
(b) 80 to 20% by weight of an inorganic filler with an average particle size of 0.01 to 5 μm (c) A plasticizer containing the above (- and (b) total weight of 100%)
A mixture consisting of 0.1 to 5 parts by weight is melt-molded into a hollow shape, and then the hollow shape is stretched at an area stretching ratio of 1.
．． A method for producing a microporous hollow fiber membrane, which comprises stretching the membrane 5 to 30 times and further removing an inorganic filler. ”

Claims (4)

[Claims] (1) Consisting of 20 to 80% by weight of polyolefin and 80 to 20% by weight of filler having an average particle diameter of 0.01 to 5 μm dispersed in the polyolefin, and having a maximum pore diameter of 5 μm.
It has a network structure consisting of communicating pores of μm or less, and the porosity is 2.
A microporous hollow fiber membrane having a molecular orientation of 0 to 90% and molecularly oriented by stretching. (2) (a) 20 to 80% by weight of polyolefin (b) Filler 80 with an average particle diameter of 0.01 to 5 μm
~20% by weight (c) A mixture containing 0.1 to 5 parts by weight of a plasticizer based on 100 parts by weight of the total amount of (a) and (b) above is melt-molded into a hollow shape, and then the hollow body is melt-molded. The area stretching ratio is 1.
A method for producing a microporous hollow fiber membrane, which comprises stretching 5 to 30 times. (3) A microporous hollow fiber membrane obtained by removing the filler from the microporous hollow fiber membrane according to claim (1). (4) (a) 20 to 80% by weight of polyolefin (b) Filler 80 with an average particle diameter of 0.01 to 5 μm
~20% by weight (c) A mixture containing 0.1 to 5 parts by weight of a plasticizer based on 100 parts by weight of the total amount of (a) and (b) above is melt-molded into a hollow shape, and then the hollow body is melt-molded. The area stretching ratio is 1.
A method for producing a microporous hollow fiber membrane, which comprises stretching the membrane 5 to 30 times and further removing a filler.