JP2955779B2 - Polyolefin composite microporous membrane and method for producing the same - Google Patents
Polyolefin composite microporous membrane and method for producing the sameInfo
- Publication number
- JP2955779B2 JP2955779B2 JP7518723A JP51872395A JP2955779B2 JP 2955779 B2 JP2955779 B2 JP 2955779B2 JP 7518723 A JP7518723 A JP 7518723A JP 51872395 A JP51872395 A JP 51872395A JP 2955779 B2 JP2955779 B2 JP 2955779B2
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- layer
- membrane
- polyolefin
- hollow fiber
- composite
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Description
【発明の詳細な説明】 技術分野 本発明は流体の限外濾過、精密濾過に有効に利用する
ことができるポリオレフィン製複合微多孔質膜、及び、
その製法に関するものである。特に、本発明は、膜補強
機能を担うポリオレフィン製微多孔質層を分離機能を担
うポリオレフィン製微多孔質層の少なくとも片面に接合
した複合多孔質膜からなる分離機能と膜強度が共に優れ
たポリオレフィン製複合微多孔質膜、及び、その製法に
関する。TECHNICAL FIELD The present invention relates to a polyolefin composite microporous membrane that can be effectively used for ultrafiltration and microfiltration of a fluid, and
It concerns the manufacturing method. In particular, the present invention provides a polyolefin composite porous membrane in which a polyolefin microporous layer serving as a membrane reinforcing function is bonded to at least one surface of a polyolefin microporous layer serving as a separating function. The present invention relates to a composite microporous membrane and a method for producing the same.
背景技術 微多孔質膜は、工業廃水処理、工業分野で用いる工程
水の処理、超純水の製造等の工業分野、エアーフィルタ
ー・バグフィルター等の空気浄化分野など幅広い分野に
使用されている。BACKGROUND ART Microporous membranes are used in a wide range of fields such as industrial wastewater treatment, treatment of process water used in the industrial field, industrial fields such as production of ultrapure water, and air purification fields such as air filters and bag filters.
このような用途に用いられる微多孔質膜材料として
は、数多くのポリマー材料を用いたものが研究され、様
々な膜が開発されている。例えば、日本特開昭57−6611
4号公報には、中空糸膜の長軸方向に配向したミクロフ
ィブリルと、中空糸膜の膜の厚さ方向に配向したスタッ
クドラメラとの結節部とから形成されるスリット上微細
孔が中空糸膜の膜壁内に積層され、かつ、膜の一表面か
ら他表面に向かって貫通しており、厚み方向に均一な微
孔構造を形成しているポリエチレン製微多孔質中空繊維
膜が開示されている。As a microporous membrane material used for such an application, a number of polymer materials have been studied, and various membranes have been developed. For example, Japanese Patent Laid-Open No. 57-6611
In Japanese Patent Publication No. 4 (1994), a micropore on the slit formed by a microfibril oriented in the major axis direction of the hollow fiber membrane and a nodule of a stack dramella oriented in the thickness direction of the hollow fiber membrane has a hollow. Disclosed is a polyethylene microporous hollow fiber membrane that is laminated within the membrane wall of the yarn membrane, penetrates from one surface of the membrane toward the other surface, and forms a uniform microporous structure in the thickness direction. Have been.
この膜は、ポリエチレンを溶融賦形し、この賦形物を
さらに延伸することによって製造されている。すなわ
ち、特定の紡糸条件でポリエチレンを賦形した後にアニ
ール処理を施して、賦形物の膜壁内にラメラ積層結晶
（スタックドラメラ）を形成させ、次いで、この賦形物
を延伸してこのスタックドラメラ間を剥離させるととも
に、ラメラ積層結晶間を結ぶフィブリルを成長させるこ
とにより、上記の特定の構造を有する微多孔質膜が形成
される。この膜は、上記特定の微多孔質構造を有してい
るため機械的強度に優れており、しかも、その製造過程
で溶剤を使用しないことから、安全性に優れるという特
徴を有している。This film is produced by melt-shaping polyethylene and further stretching the shaped material. That is, after shaping polyethylene under specific spinning conditions, an annealing treatment is performed to form lamellar laminated crystals (stack dramella) in the film wall of the shaped object, and then the shaped object is stretched by stretching. The microporous film having the above specific structure is formed by separating the stack lamellas and growing fibrils connecting the lamella stacked crystals. This film has the above-mentioned specific microporous structure, and thus has excellent mechanical strength, and further, has the feature of being excellent in safety because no solvent is used in the production process.
しかしながら、上記方法で作ったポリエチレン製微多
孔質膜は微孔の積層構造が膜の厚さ方向に対して均質な
構造をとっており、その実施例に示されたデータよりす
ると、この膜の平均孔径は0.82μｍ（水銀ポロシメータ
ー法にて測定）であり透水量は4.2l/m2.hr.mmHgなる特
性を有する膜であり、その透水量は大きいが分画特性が
十分な膜ではない。However, the polyethylene microporous membrane made by the above method has a layered structure of micropores that is uniform in the thickness direction of the membrane. The average pore size is 0.82μm (measured by the mercury porosimeter method), and the water permeability is 4.2l / m 2 .hr.mmHg. The membrane has the characteristic that the water permeability is large but the fractionation characteristics are not sufficient. .
また、日本特公平３−70539号公報には、この微多孔
質膜をエチレン−ビニルアルコール系共重合体で被覆し
た図４に示すような親水化ポリエチレン製微多孔質膜が
示されており、この膜は1.1〜20.2l/m2.hr.mmHgの透水
性能を有している。しかしながら、微細孔が全体に均一
なる３次元網目構造をなしているため、高分画性のもの
ほど透水性能は低くなり、例えばバブルポイント法から
求めた最大孔径が0.15μｍの膜では、透水性能が1.1
／m2.hr.mmHgと低く、高分画領域においては必ずしもそ
の透水性が十分なものとはいえない。Japanese Patent Publication No. 3-70539 discloses a microporous membrane made of hydrophilic polyethylene as shown in FIG. 4 in which this microporous membrane is coated with an ethylene-vinyl alcohol copolymer. This membrane has a water permeability of 1.1 to 20.2 l / m 2 .hr.mmHg. However, since the pores have a three-dimensional network structure in which the entire pores are uniform, the higher the fractionability, the lower the water permeability. For example, in the case of a membrane having a maximum pore diameter of 0.15 μm obtained by the bubble point method, the water permeability is poor. Is 1.1
/ M 2 .hr.mmHg, and the water permeability is not always sufficient in a high fractionation region.
また、日本特公昭62−44046号公報、日本特開昭62−2
69706号公報には、異種の微多孔質構造の層を接合した
複合中空糸膜の発明が開示されている。しかし、これら
の発明により得られた膜の空気の透過量は23,000l/m2.h
r.0.5kg.cm-2と示されており、ガス分離膜としては有効
に利用し得るが、その透水量は極めて小さいものと考え
られ、これらの膜を液体処理用の膜として用いることは
できない。Also, Japanese Patent Publication No. 62-44046, Japanese Patent Application
JP 69706 discloses an invention of a composite hollow fiber membrane in which layers of different microporous structures are joined. However, the air permeability of the membranes obtained by these inventions is 23,000 l / m 2 .h
r.0.5kg.cm -2, which can be used effectively as a gas separation membrane, but its water permeability is considered to be extremely small, and it is not possible to use these membranes as liquid treatment membranes. Can not.
発明の開示 これらの微多孔質膜において透水量を大きくするため
には、多孔質膜の膜厚をより小さくすればよいが、その
場合、微多孔質膜の機械的強度が不足する傾向となる。
逆に膜厚を大きくすると、微多孔質膜の機械的強度は大
きくなるが、透水量が低下する。そこで、本発明者等
は、両要請を共に満足させるために、所定の粒径の粒子
を分離できる微孔を有する多孔質膜に、それより所定比
だけ大きな微孔を有する微多孔質膜が接合された複合微
多孔質膜の構成とすることにより、膜厚の拡大にかかわ
らず膜の透水量の低下の少ない複合多孔質膜を作り得る
ことを見出した。すなわち、本発明者等は、高分画（阻
止可能な粒子の直径が0.050μｍ以上）であり、高フラ
ックス（水の透過速度が0.5l/m2.hr.mmHg以上、好まし
くは0.8l/m2.hr.mmHg以上、特に好ましくは１／m2.h
r.mmHg以上）なる特性を備えたポリオレフィン製微多孔
質膜を得ることを目的として検討した結果、本発明を完
成したものである。DISCLOSURE OF THE INVENTION In order to increase the amount of water permeation in these microporous membranes, the thickness of the porous membrane may be reduced, but in that case, the mechanical strength of the microporous membrane tends to be insufficient. .
Conversely, when the film thickness is increased, the mechanical strength of the microporous film increases, but the water permeability decreases. In order to satisfy both requirements, the present inventors have proposed a porous membrane having pores capable of separating particles having a predetermined particle size, and a microporous membrane having pores larger by a predetermined ratio than the porous membrane. It has been found that by using a composite microporous membrane that has been joined, a composite porous membrane with a small decrease in water permeability can be produced irrespective of the increase in film thickness. That is, the present inventors have a high fraction (the diameter of particles that can be blocked is 0.050 μm or more) and a high flux (water permeation rate is 0.5 l / m 2 .hr.mmHg or more, preferably 0.8 l / m 2 .hr.mmHg or more, particularly preferably 1 / m 2 .h
The present invention has been completed as a result of studies aimed at obtaining a polyolefin microporous membrane having characteristics of r.mmHg or more.
本発明の要旨とするところは、膜強度補強機能を担う
微多孔質層ｂ層を分離機能を担う微多孔質層ａ層の少な
くとも片面に接合したポリオレフィン製複合微多孔質膜
であり、ａ層及びｂ層の各層が延伸軸方向に配向したミ
クロフィブリル束と、ミクロフィブリル束の両端におい
て結合したスタックドラメラの結節部にて構成される微
孔の積層体にて構成され、これら微孔が複合微多孔質膜
の一表面から他表面にわたって連通孔を形成しており、
該微多孔質膜の微孔を構成するミクロフィブリル束とス
タックドラメラの結節部が３〜30重量％の親水性高分子
にて覆われており、ａ層中に存在する微孔のミクロフィ
ブリル束間の平均距離Daとｂ層中に存在する微孔のミク
ロフィブリル束間の平均距離Dbとの比が1.3≦Db/Da≦15
なる範囲にあることを特徴とするポリオレフィン製複合
微多孔質膜にある。The gist of the present invention is a polyolefin composite microporous membrane in which a microporous layer b serving as a membrane strength reinforcing function is bonded to at least one surface of a microporous layer a serving as a separating function. And each layer of the b layer is composed of a microfibril bundle oriented in the stretching axis direction, and a laminate of micropores composed of knot portions of a stack dramella joined at both ends of the microfibril bundle, and these micropores are formed. A communication hole is formed from one surface of the composite microporous membrane to the other surface,
The microfibril bundle forming the micropores of the microporous membrane and the nodule of the stack dramella are covered with 3 to 30% by weight of a hydrophilic polymer, and the microfibrils of the micropores present in the a layer The ratio of the average distance Da between the bundles to the average distance Db between the microfibril bundles of the micropores present in the b layer is 1.3 ≦ Db / Da ≦ 15
A polyolefin composite microporous membrane characterized by being within a certain range.
図面の簡単な説明 第１図は、実施例１の複合微多孔質膜の透過型電子顕
微鏡による断面写真である。（倍率:2900倍） 第２図は、実施例２の複合微多孔質膜の透過型電子顕
微鏡による断面写真である。（倍率:2900倍） 第３図は、溶融延伸法により開孔を行ったポリオレフ
ィン製微多孔質膜プレカーサーを示す模式図である。１
はミクロフィブリル、２はスタックドラメラ、３はスリ
ット状の微孔である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional photograph of the composite microporous membrane of Example 1 taken by a transmission electron microscope. FIG. 2 is a cross-sectional photograph of the composite microporous membrane of Example 2 taken with a transmission electron microscope. (Magnification: 2900 times) FIG. 3 is a schematic diagram showing a polyolefin microporous membrane precursor that has been opened by a melt drawing method. 1
Is a microfibril, 2 is a stack dramella, and 3 is a slit-like micropore.
第４図は、溶融延伸法により開孔を行ったポリオレフ
ィン製微多孔質膜プレカーサーを親水性共重合体で親水
化処理して得られた本発明の親水化微多孔質膜を示す摸
式図である。１′はミクロフィブリル束、２′はスタッ
クドラメラ、３′は楕円状微細孔である。FIG. 4 is a schematic diagram showing a hydrophilic microporous membrane of the present invention obtained by hydrophilizing a polyolefin microporous membrane precursor that has been opened by a melt drawing method with a hydrophilic copolymer. It is. 1 'is a microfibril bundle, 2' is a stack lamella, and 3 'is an elliptical micropore.
第５図は、微孔のミクロフィブリル束間の平均距離の
測定方法を説明した図面である。FIG. 5 is a drawing for explaining a method for measuring an average distance between microfibril bundles of micropores.
発明を実施するための最良の形態 本発明の微多孔質膜は膜厚が５〜500μの範囲にあ
り、補強機能を受け持つ微多孔質層ｂ層が分離機能を受
け持つ微多孔質層ａ層の少なくとも片面に積層されてい
る複層構造となっている。本発明の微多孔質膜の構造
は、例えば、ａ層の片面にｂ層が積層された二層構造の
もの、ａ層の両面にｂ層が積層された三層構造でもよ
い。BEST MODE FOR CARRYING OUT THE INVENTION The microporous membrane of the present invention has a thickness in the range of 5 to 500 μm, and the microporous layer b having a reinforcing function is a layer of a microporous layer a having a separating function. It has a multilayer structure laminated on at least one side. The structure of the microporous membrane of the present invention may be, for example, a two-layer structure in which the b layer is laminated on one side of the a layer, or a three-layer structure in which the b layer is laminated on both sides of the a layer.
ａ層及びｂ層は、微孔を有しており、該微孔は膜の延
伸軸方向に配列しており、かつ、該微小空孔はａ層内、
ｂ層内、及び、ab層間で互いに連通して、該複合微多孔
質膜の一方の表面から他方の表面まで積層連通した微孔
を形成している。The a layer and the b layer have micropores, the micropores are arranged in the direction of the stretching axis of the film, and the micropores are in the a layer,
Micropores that communicate with each other in the b-layer and between the ab-layers from one surface to the other surface of the composite microporous film are formed.
ａ層において形成される微孔は、膜の延伸軸方向に配
列したミクロフィブリル束と、膜の延伸軸と垂直方向に
配列したスタックドラメラとの結節部とから形成され、
ミクロフィブリル束と該結節部との間隙部分が楕円状微
細孔となっている。The micropores formed in the a layer are formed from microfibril bundles arranged in the direction of the stretching axis of the membrane, and nodes of the stack dramella arranged in the direction perpendicular to the stretching axis of the membrane,
The gap between the microfibril bundle and the node is an elliptical micropore.
ａ層中の微孔の大きさとしては、ミクロフィブリル束
間の平均距離Daで、0.1〜0.8μｍであることが好まし
く、より好ましくは0.3〜0.5μｍの範囲である。ミクロ
フィブリル束間の平均距離Daを0.3μｍ以上とした本発
明の微多孔質膜で透水量が良好であり、また、Daが0.5
μｍ以下の微多孔質膜は微粒子の阻止能力が良好、つま
り高分画な膜となっている。The size of the micropores in the a layer is preferably 0.1 to 0.8 μm, more preferably 0.3 to 0.5 μm, as the average distance Da between the microfibril bundles. The microporous membrane of the present invention in which the average distance Da between the microfibril bundles is 0.3 μm or more has a good water permeability, and has a Da of 0.5
A microporous membrane of μm or less has a good ability to block fine particles, that is, a highly fractionated membrane.
ａ層の厚みは、0.5〜20μｍであることが好ましく、
より好ましくは３〜12μｍの範囲である。ａ層の厚みを
0.5μｍ未満とすると、ａ層中にピンホール欠陥が発生
しやすい傾向にあり、一方、ａ層の厚みを20μｍを越え
たものとすると、複合微多孔質膜の透水量が低下する傾
向にある。またａ層の膜厚は全膜厚の1/3以下であるこ
とが好ましく、これより厚い複合微多孔質膜は透水性能
が急激に低下する。The thickness of the a layer is preferably 0.5 to 20 μm,
More preferably, it is in the range of 3 to 12 μm. a layer thickness
When the thickness is less than 0.5 μm, pinhole defects tend to be easily generated in the a layer. On the other hand, when the thickness of the a layer exceeds 20 μm, the water permeability of the composite microporous membrane tends to decrease. . Further, the thickness of the a layer is preferably 1/3 or less of the total thickness, and a composite microporous membrane having a thickness larger than this value sharply reduces water permeability.
微多孔質層ｂ層は、複合膜において分離機能を受け持
つ微多孔質層ａ層を支持する補強機能を担っている。ｂ
層もａ層と同じく膜の延伸軸方向に配向した微孔の積層
構造を有しており、この微孔はミクロフィブリル束とス
タックドラメラの結節部とから形成されている。ｂ層中
の微孔の大きさとしては、ミクロフィブリル束間の平均
距離Dbで、0.2〜１μｍであることが好ましく、より好
ましくは0.4〜0.5μｍの範囲である。Dbが0.2μｍ未満
なる微孔からなるｂ層を有する複合微多孔質膜では水透
過速度が低下する傾向にあり、一方、Dbが１μｍを越え
る場合、微孔を有するｂ層を備えた複合微多孔質膜の機
械的強度が低下する傾向にある。The microporous layer b has a reinforcing function of supporting the microporous layer a serving as a separating function in the composite membrane. b
The layer also has a layered structure of micropores oriented in the direction of the stretching axis of the film similarly to the layer a, and the micropores are formed from the microfibril bundle and the nodes of the stack dramella. The size of the micropores in the layer b is preferably 0.2 to 1 μm, more preferably 0.4 to 0.5 μm, as the average distance Db between the microfibril bundles. In a composite microporous membrane having a b layer composed of micropores having a Db of less than 0.2 μm, the water permeation rate tends to decrease. On the other hand, when Db exceeds 1 μm, a composite microporous membrane having a b layer having a micropore is provided. The mechanical strength of the porous membrane tends to decrease.
また、ｂ層中のスタックドラメラの結節部間平均距離
Lbは、0.4〜4.0μｍであることが好ましく、より好まし
くは0.7〜2.0μｍの範囲である。Lbが0.4μｍ未満なる
微孔からなるｂ層を有する複合微多孔質膜では水透過速
度が低下する傾向にあり、Lbが4.0μｍを越える場合、
複合微多孔質膜の機械的強度が低下する傾向にある。In addition, the average distance between the nodes of the stacked dramella in the b layer
Lb is preferably from 0.4 to 4.0 μm, more preferably from 0.7 to 2.0 μm. In a composite microporous membrane having a b layer composed of micropores with Lb less than 0.4 μm, the water permeation rate tends to decrease, and when Lb exceeds 4.0 μm,
The mechanical strength of the composite microporous membrane tends to decrease.
本発明では、DbとDaの比が1.3≦Db/Da≦15なる範囲で
あることが必要である。Db/Daが1.3未満の複合微多孔質
膜では、本発明の目的とする高分画で透水量が大きい膜
とはなりにくい。また、Db/Daが15を越えるような複合
微多孔質膜は、その膜を安定に製造することが難しい傾
向にある。In the present invention, the ratio of Db and Da needs to be in a range of 1.3 ≦ Db / Da ≦ 15. A composite microporous membrane having a Db / Da of less than 1.3 is unlikely to be a high-fractionation membrane with a high water permeability, which is the object of the present invention. Also, a composite microporous membrane having a Db / Da of more than 15 tends to have difficulty in producing the membrane stably.
本発明の複合微多孔質膜では、バブルポイント法によ
り求めた膜の最大孔径が0.05〜1.0μｍなる範囲にある
ことが好ましい。最大孔径が0.05μｍ未満の複合微多孔
質膜では水透過速度が低下する傾向にあり、1.0μｍを
越える場合、機械的強度が低下する。In the composite microporous membrane of the present invention, the maximum pore size of the membrane determined by the bubble point method is preferably in the range of 0.05 to 1.0 μm. In a composite microporous membrane having a maximum pore diameter of less than 0.05 μm, the water permeation rate tends to decrease, and when it exceeds 1.0 μm, the mechanical strength decreases.
本発明の複合微多孔質膜の特徴は、微多孔質膜が上記
の複合構造を有しているため、高分画で高フラックスで
あることにある。高フラックスの水準としては、本発明
の複合微多孔質膜の分画する粒子の径、例えば、阻止可
能な粒子径が0.050μｍ以上の分野で使う場合に、透水
量が0.5l/m2.hr.mmHg以上、より好ましく１／m2.hr.m
mHg以上である。複合微多孔質膜の阻止可能な粒子の直
径が0.100μｍ以上の分野で使う場合には、透水量が2l/
m2.hr.mmHg以上であることが好ましく、より好ましくは
3l/m2.hr.mmHg以上、さらに好ましくは5l/m2.hr.mmHg以
上である。また、複合微多孔質膜の阻止可能な粒子の直
径が0.170μｍ以上の分野で使う場合には、透水量が5l/
m2.hr.mmHg以上であることが好ましい。A feature of the composite microporous membrane of the present invention is that the microporous membrane has the above-described composite structure, and thus has high fractionation and high flux. As the high flux level, the diameter of the particles to be fractionated by the composite microporous membrane of the present invention, for example, when used in the field where the rejectable particle diameter is 0.050 μm or more, the water permeability is 0.5 l / m 2 . hr.mmHg or more, more preferably 1 / m 2 .hr.m
mHg or more. When the composite microporous membrane is used in fields where the diameter of the particles that can be blocked is 0.100 μm or more, the water permeability is 2 l /
m 2 .hr.mmHg or more, more preferably
It is at least 3 l / m 2 .hr.mmHg, more preferably at least 5 l / m 2 .hr.mmHg. Further, when the composite microporous membrane is used in a field where the diameter of the particles that can be blocked is 0.170 μm or more, the water permeability is 5 l /
It is preferably at least m 2 .hr.mmHg.
本発明の微多孔質膜を形成する素材として用いるポリ
オレフィン類は、例えば、ポリエチレン、ポリプロピレ
ン、ポリ−３−メチルブテン−１、ポリ−４−メチルペ
ンテン−１、ポリフッ化ビニリデン単独又はこれら重合
体の混合物を用いることができる。Polyolefins used as a material for forming the microporous membrane of the present invention include, for example, polyethylene, polypropylene, poly-3-methylbutene-1, poly-4-methylpentene-1, polyvinylidene fluoride alone or a mixture of these polymers. Can be used.
本発明の微多孔質膜の用途が医療用途である場合に
は、膜素材として溶出成分の含有量が少なく、かつ、血
液適合性を備えた素材が好ましい。また、本発明の微多
孔質膜の用途が工業用途である場合には、耐久性、機械
的特性が良好な膜を作り得る素材を選定するのがよい。When the use of the microporous membrane of the present invention is for medical use, a material having a low content of eluted components and having blood compatibility is preferable as the membrane material. Further, when the use of the microporous membrane of the present invention is an industrial use, it is preferable to select a material capable of forming a membrane having good durability and mechanical properties.
本発明において用いるポリオレフィン類のASTM D−12
38によって測定したMI値（メルトインデックス値）は0.
1〜50の範囲、好ましくは0.3〜15の範囲である。MI値が
0.1未満のポリオレフィンはその溶融粘度が高過ぎるた
め、その賦形が難しく所望とする微多孔質膜を作ること
ができない。またMI値が50を越えるポリオレフィンは逆
に溶融粘度が低過ぎて安定な賦形を行うことができな
い。ASTM D-12 of polyolefins used in the present invention
The MI value (melt index value) measured by 38 is 0.
It is in the range of 1 to 50, preferably 0.3 to 15. MI value
Since the melt viscosity of a polyolefin of less than 0.1 is too high, its shaping is difficult and a desired microporous membrane cannot be produced. On the other hand, a polyolefin having an MI value of more than 50 has too low a melt viscosity to perform stable shaping.
本発明を実施するに際して用いるポリオレフィンの密
度は用いる素材によって異なるが、例えばポリエチレン
の場合には0.95g/cm3以上であることが好ましく、ポリ
プロピレンの場合には0.91g/cm3以上であることが好ま
しい。Density of the polyolefin used in the practice of the present invention varies depending on the material used, be for example in the case of polyethylene is preferably 0.95 g / cm 3 or more, in the case of polypropylene is 0.91 g / cm 3 or more preferable.
本発明の微多孔質膜を作るに際し、ａ層形成用ポリオ
レフィンのMI値MIaとｂ層形成用ポリオレフィンのMI値M
IbとはMIa＜MIbとなるように選定すると、ａ層形成用ポ
リオレフィンの密度ρａと、ｂ層形成用ポリオレフィン
ρｂがほぼ等しくても、本発明の複合微多孔質膜を得る
ことができる。In producing the microporous membrane of the present invention, the MI value MIa of the polyolefin for forming the a layer and the MI value M of the polyolefin for forming the b layer
If Ib is selected so as to satisfy MIa <MIb, the composite microporous membrane of the present invention can be obtained even if the density ρa of the polyolefin for forming the a layer and the polyolefin ρb for forming the b layer are substantially equal.
逆に、ρａ＜ρｂとなる様にそれぞれのポリオレフィ
ンを選定すると、MIa、MIbがほぼ等しくても、本発明の
複合微多孔質膜を得ることができる。Conversely, if each polyolefin is selected such that ρa <ρb, the composite microporous membrane of the present invention can be obtained even if MIa and MIb are substantially equal.
好ましくは、MIa＜MIb、ρａ＜ρｂなる関係を両方満
たす様に、それぞれのポリオレフィンを選定すると、本
発明の複合微多孔質膜を効率よく作ることができる。Preferably, when each polyolefin is selected so as to satisfy both the relations MIa <MIb and ρa <ρb, the composite microporous membrane of the present invention can be efficiently produced.
なお、本発明でいう微孔のミクロフィブリル束間の平
均距離は次の如くして測定したものである。The average distance between microfibril bundles of micropores in the present invention is measured as follows.
微多孔質膜より膜の延伸方向に極薄切片を切出したサ
ンプルの6500倍の透過型電子顕微鏡写真より6cm角の部
分を画像処理装置のCRT画面に取り込む（第５図にこの
画像を示す）。取込画像の上辺部より膜延伸方向に直角
となる方向に、下辺部まで、順次0.052μｍピッチで１
本目からｎ本目までの走査線を引く。そして、αで表示
したミクロフィブリル束間の平均距離が測定できない部
分は除外して、１本目の走査線の内、孔部部分を通過す
る線分の各距離、例えばa1からa5の和を求め、次いで、
２本目の走査線について同様に例えばb1からb6の和を求
め、順次ｎ本目の走査線の例えばn1からn6の和を求めて
総和（距離総和）を出す。次に、各走査線が通過した微
孔の数（１本目の走査線では５つ、２本目は６つ、ｎ本
目は６つ）の総和（数総和）を求めて、距離総和／数総
和を平均間隔Da、Dbとする。A 6 cm square portion of a sample obtained by cutting an ultrathin section from the microporous membrane in the stretching direction of the membrane in a transmission electron microscope photograph of 6500 times is taken into a CRT screen of an image processing apparatus (this image is shown in FIG. 5). . In the direction perpendicular to the film stretching direction from the upper side of the captured image, to the lower side, 1 at a pitch of 0.052 μm.
From the first to n-th scanning lines are drawn. Then, the average distance can not be measured portion between the indicated microfibril bundles in α are excluded, among the first scanning lines, the sum of a 5 each distance of the line segment, for example, from a 1 passing through the hole portion And then
It calculates the sum of b 6 from Similarly example b 1 for the two-th scanning line, issuing a total seek the sum of n 6 from example n 1 of the sequence n-th scan line (distance sum). Next, the sum (number sum) of the number of micropores passed by each scanning line (5 in the first scanning line, 6 in the second scanning line, and 6 in the nth scanning line) is obtained, and the total distance / the total number of numbers is obtained. Are the average intervals Da and Db.
本発明の複合微多孔質膜を作るには、先ず中間体たる
複合多孔質膜プレカーサーを作り、次いで、親水性共重
合体で被覆処理を行えばよい。そして該プレカーサーを
作るには、上記条件を満足したポリオレフィンを選定
し、複合紡糸法によって製膜するのがよい。In order to prepare the composite microporous membrane of the present invention, first, a composite porous membrane precursor as an intermediate may be prepared, and then a coating treatment with a hydrophilic copolymer may be performed. In order to make the precursor, it is preferable to select a polyolefin satisfying the above conditions and form a film by a composite spinning method.
複合微多孔質膜プレカーサーが中空糸膜形状である場
合には、同心円状に配設した二つ以上の円環状の吐出口
を有するノズルを用いるのがよい。When the composite microporous membrane precursor is in the form of a hollow fiber membrane, it is preferable to use a nozzle having two or more annular discharge ports arranged concentrically.
紡糸温度としては、ポリオレフィンの融点以上（好ま
しくは融点より10〜100℃高い温度とする）、吐出物は1
0〜40℃の雰囲気中0.1〜3m/秒なる引取速度で引取り、
得られた多層体を、そのままか、又は、ポリオレフィン
の融点以下の温度（好ましくは融点より５〜50℃低い温
度）で熱処理を行ってスタックドラメラを形成させた
後、延伸し多層体に開孔処理を行う。延伸は冷延伸に引
き続き、熱延伸を行うのがよい。冷延伸は、比較的低い
温度で多層体の構造破壊を起こさせてスタックドラメラ
間にミクロクラックを発生させる過程であり、この冷延
伸は０℃〜ポリマーの融点より50℃低い温度の範囲で行
うのが好ましい。ポリオレフィンとしてポリエチレンを
用いた場合、この冷延伸温度は０〜80℃、好ましくは10
〜50℃の範囲である。また、冷延伸倍率としては、５〜
100％が好ましい。５％以下ではミクロクラックの発生
が不十分となり、目的とする孔径が得られ難くなる。ま
た、100％以上ではミクロクラックの発生数が多くなり
支持層（ｂ層）に目的とする大きい孔径を形成し難くな
る。The spinning temperature is higher than the melting point of the polyolefin (preferably 10 to 100 ° C. higher than the melting point).
Take off at a take-off speed of 0.1 to 3 m / sec in an atmosphere of 0 to 40 ° C,
The obtained multilayer body is heat-treated as it is or at a temperature equal to or lower than the melting point of the polyolefin (preferably a temperature lower by 5 to 50 ° C. than the melting point) to form a stack dramella, and then stretched and opened into a multilayer body. Perform hole processing. The stretching is preferably performed by hot stretching following cold stretching. Cold stretching is a process of causing microstructure cracks between stacked lamellae by causing structural destruction of a multilayer body at a relatively low temperature, and the cold stretching is performed at a temperature ranging from 0 ° C to 50 ° C lower than the melting point of the polymer. It is preferred to do so. When polyethylene is used as the polyolefin, the cold stretching temperature is 0 to 80 ° C, preferably 10 to 80 ° C.
In the range of ~ 50 ° C. In addition, the cold stretch ratio is 5 to 5.
100% is preferred. If it is less than 5%, the generation of microcracks becomes insufficient, and it becomes difficult to obtain a target pore diameter. On the other hand, if it is 100% or more, the number of generated microcracks increases, and it becomes difficult to form a target large pore size in the support layer (layer b).
次いで行う熱延伸は多層体中に発生させたミクロクラ
ックを拡大させ、スタックドラメラ間にミクロフィブリ
ルを形成せしめ、スリット状の微孔を有する多孔質膜と
する過程である。熱延伸温度としては、ポリオレフィン
の融点を越えない範囲で、できるだけ高い温度で行うの
がよい。また、熱延伸倍率としては、目的とする孔径に
より適宜選定すればよいが、50〜2000％、好ましくは10
0〜1000％の範囲とするのが工程安定性の点でよい。The subsequent hot stretching is a process of expanding microcracks generated in the multilayer body, forming microfibrils between the stacked lamellae, and forming a porous film having slit-like micropores. The hot stretching temperature is preferably as high as possible without exceeding the melting point of the polyolefin. Further, the heat stretching ratio may be appropriately selected depending on the target pore diameter, but is preferably 50 to 2000%, preferably 10 to 2000%.
The range of 0 to 1000% is good in view of process stability.
さらに得られた微多孔質膜プレカーサーの寸法安定性
を得るため、この膜を定長下、または、少し弛緩させた
状態で熱セットを行う。熱セットを効果的に行うために
は、熱セット温度は延伸温度以上、融点温度以下である
ことが好ましい。Further, in order to obtain the dimensional stability of the obtained microporous membrane precursor, the membrane is heat-set under a fixed length or in a state of being slightly relaxed. In order to perform heat setting effectively, the heat setting temperature is preferably equal to or higher than the stretching temperature and equal to or lower than the melting point temperature.
次に、得られた多層複合膜プレカーサーに恒久親水性
を付与する工程を行う。本発明で用いる親水性共重合体
は、エチレンを20モル％以上、親水性モノマーを10モル
％以上含む共重合体であり、これら共重合体は、ランダ
ムコポリマー、ブロックコポリマー、グラフトコポリマ
ー等いずれのタイプの共重合体であってもよい。Next, a step of imparting permanent hydrophilicity to the obtained multilayer composite film precursor is performed. The hydrophilic copolymer used in the present invention is a copolymer containing 20 mol% or more of ethylene and 10 mol% or more of a hydrophilic monomer, and these copolymers may be any of a random copolymer, a block copolymer, and a graft copolymer. It may be a type copolymer.
共重合体に占めるエチレン含量が20モル％未満では、
共重合体はプレカーサーに対して親和性が弱く、プレカ
ーサーを親水性共重合体溶液に浸漬処理し、プレカーサ
ー100重量％に対して３〜30重量％なる割合で親水性共
重合体を被覆することができず、好ましくない。If the ethylene content in the copolymer is less than 20 mol%,
The copolymer has a weak affinity for the precursor, and the precursor is immersed in a hydrophilic copolymer solution, and the hydrophilic copolymer is coated at a ratio of 3 to 30% by weight with respect to 100% by weight of the precursor. Is not preferred.
本発明で使用する親水性共重合体を重合する際に使用
する親水性モノマーとしては、例えばビニルアルコー
ル、（メタ）アクリル酸及びその塩、ヒドロキシエチル
（メタ）アクリレート、ポリエチレングリコール（メ
タ）アクリル酸エステル、ビニルピロリドン、アクリル
アミド等のビニル化合物をあげることができ、これら親
水性モノマーが一種以上含まれていればよいが、特に好
ましいモノマートしてビニルアルコールをあげることが
できる。また、本発明に用いる親水性共重合体は、エチ
レン及び親水性モノマー以外の第三成分を一種以上含ん
でいてもよく、第三成分としては例えば酢酸ビニル、
（メタ）アクリル酸エステル、ビニルアルコール脂肪酸
エステル、ビニルアルコールのフォルマール化物若しく
はブチラール化物等をあげることができる。Examples of the hydrophilic monomer used for polymerizing the hydrophilic copolymer used in the present invention include vinyl alcohol, (meth) acrylic acid and salts thereof, hydroxyethyl (meth) acrylate, and polyethylene glycol (meth) acrylic acid. Examples thereof include vinyl compounds such as esters, vinylpyrrolidone, and acrylamide. It is sufficient that at least one of these hydrophilic monomers is contained, and a particularly preferred monomer is vinyl alcohol. Further, the hydrophilic copolymer used in the present invention may include one or more third components other than ethylene and the hydrophilic monomer, for example, vinyl acetate,
(Meth) acrylic acid ester, vinyl alcohol fatty acid ester, formalized or butyralized vinyl alcohol, and the like can be mentioned.
微多孔質膜プレカーサーへの親水性共重合体の被覆量
はプレカーサー重量換算で３〜30重量％の範囲とする。
親水性共重合体の被覆量が３重量％未満の微多孔質膜は
水との親和性が乏しく、微多孔質膜への通水性が不足
し、一方、親水性共重合体の被覆量が30重量％を越えて
多くなると共重合体による微多孔質膜の孔の閉塞などが
起こり易く、その透水性が低下し易い。The coating amount of the hydrophilic copolymer on the microporous membrane precursor is in the range of 3 to 30% by weight in terms of the precursor weight.
A microporous membrane having a hydrophilic copolymer coating amount of less than 3% by weight has poor affinity for water and lacks water permeability to the microporous membrane, while the hydrophilic copolymer coating amount is low. If the content exceeds 30% by weight, the pores of the microporous membrane are likely to be blocked by the copolymer, and the water permeability tends to decrease.
本発明において用いられる共重合体の溶剤は、水混和
性有機溶剤であることが好ましく、その具体例として
は、メタノール、エタノール、Ｎ−プロパノール、イソ
プロピルアルコール等のアルコール類、ジメチルスルホ
キシド、ジメチルホルムアミド等をあげることができ
る。これら溶剤は単独でも用い得るが、水との混合物は
親水性共重合体に対する溶解性が強いので、より好まし
い。また、親水性共重合体を被覆した微多孔質膜を乾燥
するに際して用いる溶剤の蒸気含有雰囲気の作り易さ、
すなわち、溶剤の蒸気圧の低さ、人体に対する低毒性の
点から、沸点100℃未満のアルコール類例えばメタノー
ル、エタノール、イロプロピルアルコール等と水の混合
系溶剤を用いることが特に好ましい。The solvent for the copolymer used in the present invention is preferably a water-miscible organic solvent, and specific examples thereof include alcohols such as methanol, ethanol, N-propanol, and isopropyl alcohol, dimethyl sulfoxide, and dimethylformamide. Can be given. These solvents can be used alone, but a mixture with water is more preferable because of its high solubility in the hydrophilic copolymer. Further, the ease of creating a vapor-containing atmosphere of a solvent used when drying the microporous membrane coated with the hydrophilic copolymer,
That is, from the viewpoint of low vapor pressure of the solvent and low toxicity to the human body, it is particularly preferable to use a mixed solvent of an alcohol having a boiling point of less than 100 ° C., such as methanol, ethanol, isopropyl alcohol and the like, and water.
水混和性有機溶剤と水との混合割合は、そのプレカー
サーの浸透性を阻害せず、共重合体の溶解を低下せしめ
ない範囲であればよく、用いられる共重合体の種類によ
っても異なるが、有機溶剤としてエタノールを用いる場
合、エタノール／水の割合は、90/10〜30/70（vol％）
の範囲であることが好ましい。The mixing ratio of the water-miscible organic solvent and water does not hinder the permeability of the precursor and may be within a range that does not reduce the dissolution of the copolymer, and varies depending on the type of the copolymer used, When ethanol is used as the organic solvent, the ratio of ethanol / water is 90/10 to 30/70 (vol%)
Is preferably within the range.
親水性共重合体溶液の濃度は、0.1〜10重量％程度、
好ましくは0.5〜５重量％の範囲である。濃度が0.1重量
％未満の溶液でプレカーサーを処理したものは親水性共
重合体の均一な被覆を行うことが難しく、10重量％を越
えると溶液粘度が大きくなり過ぎ、該溶液でプレカーサ
ーを処理すると、多層複合膜の微孔が共重合体で閉塞さ
れてしまう。親水性共重合体溶液にプレカーサーを浸漬
する方法としては、同じ濃度の共重合体溶液に２回以上
浸漬処理を行ってもよく、濃度の異なる溶液に浸漬を２
回以上行ってもよい。The concentration of the hydrophilic copolymer solution is about 0.1 to 10% by weight,
Preferably it is in the range of 0.5 to 5% by weight. When the precursor is treated with a solution having a concentration of less than 0.1% by weight, it is difficult to uniformly coat the hydrophilic copolymer, and when the concentration exceeds 10% by weight, the solution viscosity becomes too large. In addition, the pores of the multilayer composite film are closed by the copolymer. As a method of immersing the precursor in the hydrophilic copolymer solution, the immersion treatment may be performed twice or more in the same concentration of the copolymer solution.
It may be performed more than once.
浸漬処理を行う親水性共重合体溶液の温度は、高い程
その粘度は低下し、プレカーサーへの溶液の浸透性が向
上し好ましいが、安全面からその溶液の沸点以下である
ことが好ましい。The higher 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 precursor. This is preferable, but from the viewpoint of safety, the temperature is preferably equal to or lower than the boiling point of the solution.
浸漬処理時間は、用いるプレカーサーの膜厚、微孔
径、空孔率により異なるが、数秒〜数分の範囲とするの
が好ましい。The immersion time varies depending on the thickness, micropore diameter, and porosity of the precursor used, but is preferably in the range of several seconds to several minutes.
プレカーサーは親水性重合体溶液に浸漬後、乾燥処理
を行う前に有機溶剤の蒸気が3vol％以上含まれ、温度が
室温から該溶剤の沸点以下の温度にある雰囲気下に立ち
上げ少なくとも30秒間以上滞在させセッティング工程を
施すことが必要である。The precursor is immersed in the hydrophilic polymer solution, and before being subjected to the drying treatment, contains at least 3 vol% of the vapor of the organic solvent, and is started in an atmosphere having a temperature from room temperature to a temperature not higher than the boiling point of the solvent, and at least 30 seconds or more. It is necessary to allow the stay to be performed and to perform a setting step.
この処理工程の目的は、プレカーサーを構成するミク
ロフィブリルとスタックドラメラとの結節部の表面に親
水性共重合体の皮膜を形成することによる微孔の閉塞を
防止することにある。又、ミクロフィブリルを結束させ
てスリット状の微孔を大孔径化して楕円状の微孔を作
り、透水量の増大を図ると共に、処理水との親和性を高
めることにある。The purpose of this treatment step is to prevent micropores from being blocked by forming a film of a hydrophilic copolymer on the surface of the node between the microfibrils and the stack dramella constituting the precursor. Another object of the present invention is to bind microfibrils to increase the diameter of slit-shaped micropores to form elliptical micropores, thereby increasing the amount of water permeation and increasing the affinity with treated water.
本セッティング工程中での親水性共重合体のプレカー
サー表面での皮膜形成を防ぐには、プレカーサー表面で
の急速な乾燥を防ぐ必要があり、そのためには、共重合
体溶液のプレカーサー表面での蒸発速度を押え、かつ、
プレカーサー表面が溶剤で濡れている状態に保つことが
必要であり、この観点から、セッティング工程の雰囲気
は水混和性有機溶剤の蒸気が3vol％以上の雰囲気下にす
ることが必要となる。In order to prevent the hydrophilic copolymer from forming a film on the precursor surface during this setting step, it is necessary to prevent rapid drying on the precursor surface, and for that purpose, evaporation of the copolymer solution on the precursor surface is required. Hold down the speed, and
It is necessary to keep the surface of the precursor wet with the solvent. From this viewpoint, it is necessary that the atmosphere of the setting step be an atmosphere in which the vapor of the water-miscible organic solvent is 3 vol% or more.
該セッティング工程におけるプレカーサーよりの溶剤
の蒸発速度は極力遅くする方が好ましく、セッティング
工程の雰囲気は溶剤の飽和蒸気濃度に近い雰囲気とする
方がよい。また、この工程でのプレカーサー面での溶剤
の蒸発を遅くするには、セッティング温度を低温にする
方がよいが、余り低過ぎるとセッティング工程での脱溶
剤が進まないという現象が起こり好ましくない。従っ
て、該雰囲気の温度は室温以上、水混和性溶剤の沸点以
下とすることが好ましい。It is preferable that the evaporation rate of the solvent from the precursor in the setting step be as low as possible, and the atmosphere in the setting step be an atmosphere close to the saturated vapor concentration of the solvent. In order to slow down the evaporation of the solvent on the precursor surface in this step, it is better to lower the setting temperature. However, if the temperature is too low, the phenomenon that the desolvation does not progress in the setting step is not preferable. Therefore, it is preferable that the temperature of the atmosphere be equal to or higher than room temperature and equal to or lower than the boiling point of the water-miscible solvent.
浸漬後のプレカーサーは浸漬浴より該雰囲気中に立ち
上げるが、立ち上げの角度は45°〜90°の範囲とするの
が好ましい。立ち上げることによりプレカーサーに付着
した共重合体溶液の一部が自重によってプレカーサーよ
り脱液される。その脱液量は、プレカーサーの浴よりの
立ち上げる速度、浸漬溶液の粘度、プレカーサーの浴面
からの立ち上げる高さ等により異なる。このセッティン
グ工程での脱液効果を高めるための補助手段として、ガ
イド、スリット等によりプレカーサー表面にある溶液の
拭き取りを併用してもよい。The precursor after immersion is raised from the immersion bath into the atmosphere, and the rising angle is preferably in the range of 45 ° to 90 °. By starting up, a part of the copolymer solution attached to the precursor is removed from the precursor by its own weight. The amount of drainage varies depending on the speed at which the precursor rises from the bath, the viscosity of the immersion solution, the height of the precursor rising from the bath surface, and the like. As an auxiliary means for enhancing the drainage effect in this setting step, wiping of the solution on the precursor surface by a guide, a slit or the like may be used together.
このセッティング時間は、少なくとも30秒が必要であ
り、この間に、溶剤のプレカーサーからの蒸発に伴う共
重合体溶液の濃縮と膜のミクロフィブリルとスタックド
ラメラ表面でのマイグレーションによる均一化が行われ
る。特に、プレカーサーを連続的に親水性共重合体溶液
にて処理する場合、このセッティング時間は、少なくと
も30秒以上必要である。30秒未満のセッティングでは溶
剤の蒸発に伴う濃縮が不十分であって、過剰の溶液がプ
レカーサーに付着した状態で乾燥を行うことになり、親
水性共重合体により微孔の閉塞が発現し、併せて、共重
合体の膜構造内での均一付着化が不十分となり、透水性
能、分画性能の良好な微多孔質膜が得られにくい。This setting time must be at least 30 seconds, during which the concentration of the copolymer solution accompanying the evaporation of the solvent from the precursor and the homogenization of the membrane by microfibrils and migration on the surface of the stacked dramellar are carried out. In particular, when the precursor is continuously treated with the hydrophilic copolymer solution, the setting time is required to be at least 30 seconds or more. In a setting of less than 30 seconds, concentration due to evaporation of the solvent is insufficient, and drying is performed in a state where excess solution is attached to the precursor, and pores are blocked by the hydrophilic copolymer, In addition, uniform adhesion of the copolymer within the membrane structure becomes insufficient, and it is difficult to obtain a microporous membrane having good water permeability and fractionation performance.
なお、上記セッティング時間を30秒とした時の溶剤の
プレカーサーからの蒸発量は、用いた親水性共重合体溶
液の15〜30％程度であることが好ましい。The amount of evaporation of the solvent from the precursor when the setting time is 30 seconds is preferably about 15 to 30% of the used hydrophilic copolymer solution.
セッティング工程でのプレカーサーよりの溶剤の蒸発
量をコントロールする方法としては、セッティング雰囲
気温度、該雰囲気中に空気や不活性ガス等の気体を送風
する方法等をあげることができる。Examples of a method for controlling the amount of evaporation of the solvent from the precursor in the setting step include a setting atmosphere temperature and a method of blowing a gas such as air or an inert gas into the atmosphere.
セッティングを終了したプレカーサーの乾燥処理は、
真空乾燥、熱風乾燥等公知の乾燥方法によればよい。乾
燥温度は複合微多孔質膜が熱によって変形を受けない温
度であればよい。例えばポリエチレン製複合微多孔質膜
の場合には120℃以下の温度で乾燥するのが好ましく、4
0〜70℃の温度で乾燥することが特に好ましい。The drying process of the precursor after setting is completed
A known drying method such as vacuum drying and hot air drying may be used. The drying temperature may be a temperature at which the composite microporous membrane is not deformed by heat. For example, in the case of a polyethylene composite microporous membrane, it is preferable to dry at a temperature of 120 ° C or less,
It is particularly preferred to dry at a temperature of 0 to 70 ° C.
複合微多孔質膜に対する親水性共重合体の付着量は、
基質である複合微多孔質膜プレカーサーの重量に対し
て、濾過特性の点からおよそ１〜30重量％、好ましくは
３〜15重量％である。The amount of the hydrophilic copolymer attached to the composite microporous membrane is
The amount is about 1 to 30% by weight, preferably 3 to 15% by weight, from the viewpoint of filtration characteristics, based on the weight of the composite microporous membrane precursor as a substrate.
この親水性共重合体の被覆処理により微多孔質膜プレ
カーサーのミクロフィブリル（図３の１）は収束されて
ミクロフィブリル束（図４の１′）となり、また、スリ
ット状微孔（図３の３）は楕円状微孔（図４の３′）と
なる。The microfibrils (1 in FIG. 3) of the microporous membrane precursor are converged into a microfibril bundle (1 'in FIG. 4) by the coating treatment with the hydrophilic copolymer, and the slit-like micropores (1 in FIG. 3). 3) is an oval micropore (3 'in FIG. 4).
以下、本発明を実施例によりさらに詳しく説明する。
なお、実施例中の各種測定、評価は下記の方法によっ
た。Hereinafter, the present invention will be described in more detail with reference to Examples.
Various measurements and evaluations in the examples were performed by the following methods.
１ 雰囲気中のエタノール濃度は、ガス検知管（商品名
｛ガステック検知管」ガステック株式会社）を用いた。1 The concentration of ethanol in the atmosphere was measured using a gas detector tube (trade name: Gastec detector tube, Gastech Co., Ltd.).
２ 親水性共重合体の被覆量は下記式に従って算出し
た。2 The coating amount of the hydrophilic copolymer was calculated according to the following equation.
３ 膜の透水量は有効膜面積70〜90cm2のミニモジュー
ルを作成し、差圧1kg/cm2でイオン交換水を濾過しその
時の透水量を測定した。 Water permeability 3 film creates a mini-module having an effective membrane area 70~90cm 2, differential pressure 1 kg / cm 2 was filtered deionized water was measured water permeability at that time.
４ ラテックス標準粒子による捕捉粒子径は、膜面積が
約50cm2の中空糸膜のモジュールで0.1wt％の界面活性剤
（ポリエチレングリコール−ｐ−イソオクチルフェニル
エーテル）水溶液で膜内の空気を置換した後、圧力0.7k
g/cm2で0.1％の所定粒子径の単一分散粒子径のポリスチ
レンラテックス粒子を濾過し、濾液のラテックス粒子の
濃度を日立分光光度計（Ｕ−3400）により320nmの波長
で測定し捕捉率を求めた。4. The diameter of the trapped particles by the latex standard particles was determined by using a hollow fiber membrane module having a membrane area of about 50 cm 2 and replacing the air in the membrane with a 0.1 wt% surfactant (polyethylene glycol-p-isooctylphenyl ether) aqueous solution. After, pressure 0.7k
The polystyrene latex particles having a monodispersed particle size of 0.1% and a predetermined particle size of 0.1 g / cm 2 are filtered, and the concentration of the latex particles in the filtrate is measured by a Hitachi spectrophotometer (U-3400) at a wavelength of 320 nm to obtain a trapping rate. I asked.
バブルポイント（以下B.P.と略す）は、膜面積約50cm2
の中空糸膜のモジュールを中空糸膜の部分が完全に浸る
ように濃度95％以上のエタノール中に浸漬する。中空糸
膜の多孔質内部がエタノールで十分濡れるように中空糸
膜内部からエタノールを100ml以上吸引した後、浸漬状
態のままで中空糸膜内部に窒素を送り込み10秒ごとに0.
1kg/cm2きざみで空気圧を昇圧する。気泡が中空糸膜の
ほぼ全表面から発生し気泡発生箇所の間隔が1mm以内に
なった時の窒素圧力をバブルポイントとする。なお、B.
P.からの平均孔径は以下の関係式より算出した。The bubble point (hereinafter abbreviated as BP) is approximately 50 cm 2
The hollow fiber membrane module is immersed in ethanol having a concentration of 95% or more so that the hollow fiber membrane portion is completely immersed. After sucking 100 ml or more of ethanol from the inside of the hollow fiber membrane so that the porous inside of the hollow fiber membrane is sufficiently wetted with ethanol, nitrogen is fed into the inside of the hollow fiber membrane while being immersed, and the nitrogen is introduced every 10 seconds.
Boosting the air pressure 1 kg / cm 2 increments. The bubble pressure is defined as the nitrogen pressure when air bubbles are generated from almost the entire surface of the hollow fiber membrane and the space between the air bubble generation points is within 1 mm. B.
The average pore diameter from P. was calculated from the following relational expression.
Ｐ＝２σcosθ/r P:圧力（バブルポイント値） σ：エタノールの表面張力 θ：エタノールと膜の接触角 r:平均細孔半径 ６ 膜の空孔率は、カルロエルバ社製水銀ポロシメータ
ー221型を用いて測定した。P = 2σ cos θ / r P: pressure (bubble point value) σ: surface tension of ethanol θ: contact angle between ethanol and the membrane r: average pore radius 6 The porosity of the membrane is a mercury porosimeter 221 manufactured by Carlo Elba. Measured.
７ 微孔のミクロフィブリル束間の平均距離は、前記の
方法で測定した。7 The average distance between microfibril bundles of micropores was measured by the method described above.
８ ａ層又はｂ層中の微孔のスタックドラメラとミクロ
フィブリル束との結節部間の平均距離La又はLbは、微孔
のミクロフィブリル束間の平均距離の測定方法と同じ方
法（ただし、走査線は膜延伸方向であり、ピッチ巾は0.
045μｍとした）で算出した。8 The average distance La or Lb between the nodes of the microporous stack dramella and the microfibril bundle in the a-layer or the b-layer is the same as the method for measuring the average distance between the microfibril bundles of the micropores (however, The scanning line is in the film stretching direction, and the pitch width is 0.
045 μm).
〈実施例１〉 密度0.968g/cm3、メルトインデックス（MI）値5.5の
高密度ポリエチレン（Hizex 2200 J、三井石油化学株式
会社製）64重量％と、密度0.968g/cm3、MI値0.35の高密
度ポリエチレン（BU004N、三菱化成株式会社製）21重量
％と、密度0.920g/cm3、MI値8.0の低密度ポリエチレン
（Ultzex 20200 J、三井石油化学株式会社製）15重量％
とを二軸押出機により温度180℃にて溶融混練し、密度
0.961g/cm3、MI値5.2のブレンドポリマーを得た。<Example 1> 64% by weight of high-density polyethylene (Hizex 2200 J, manufactured by Mitsui Petrochemical Co., Ltd.) having a density of 0.968 g / cm 3 and a melt index (MI) value of 5.5, a density of 0.968 g / cm 3 , and an MI value of 0.35 21% by weight of high-density polyethylene (BU004N, manufactured by Mitsubishi Kasei Corporation) and 15% by weight of low-density polyethylene (Ultzex 20200 J, manufactured by Mitsui Petrochemical Co., Ltd.) having a density of 0.920 g / cm 3 and MI value of 8.0
Are melt-kneaded at a temperature of 180 ° C by a twin-screw extruder,
A blend polymer having 0.961 g / cm 3 and an MI value of 5.2 was obtained.
次に、このブレンドポリマーをａ層形成用ポリマーと
して上記の密度0.968g/cm3、MI値5.5の高密度ポリエチ
レンをｂ層形成用ポリマーとして同心円状に配置された
二つの円管状の吐出口を有する中空糸製造用ノズルを用
いて吐出温度158℃、巻取速度80m/分にて溶融紡糸し
た。このとき、外側の吐出口からブレンドポリマー、内
側の吐出口から前記高密度ポリエチレンをそれぞれ吐出
量比1/5、吐出線速度3.01cm/分、ドラフト比2560となる
ように吐出した。さらに、ノズルから吐出された糸に温
度20℃、風速3.0m/秒の冷却風を糸の周囲に均一に流し
ながら巻取り、未延伸複合中空糸を得た。Next, the above-mentioned blended polymer was used as a polymer for forming the a layer, and two high-density polyethylenes having a density of 0.968 g / cm 3 and an MI value of 5.5 were concentrically arranged as the polymer for forming the b layer. It was melt spun at a discharge temperature of 158 ° C. and a take-up speed of 80 m / min using a hollow fiber production nozzle. At this time, the blended polymer was discharged from the outer discharge port, and the high-density polyethylene was discharged from the inner discharge port so that the discharge amount ratio was 1/5, the discharge linear velocity was 3.01 cm / min, and the draft ratio was 2560. Furthermore, the yarn discharged from the nozzle was wound while cooling air having a temperature of 20 ° C. and a wind speed of 3.0 m / sec was uniformly flowed around the yarn to obtain an undrawn composite hollow fiber.
得られた未延伸中空糸を115℃に加熱した空気中で定
長のまま12時間アニール処理を行った。さらに、このア
ニール処理糸を30℃に保たれたローラー間で80％冷延伸
し引き続いて108℃に加熱した加熱炉中で総延伸量が400
％になるようにローラー間熱延伸を行い、さらに、115
℃に加熱した加熱函中で総延伸量の25％を緩和させた状
態で熱セットを行い、複合微多孔質中空糸膜プレカーサ
ーを得た。The obtained undrawn hollow fiber was annealed for 12 hours in the air heated to 115 ° C. while keeping the fixed length. Further, the annealed yarn was cold-drawn by 80% between rollers maintained at 30 ° C., and subsequently the total drawn amount was 400 ° C. in a heating furnace heated to 108 ° C.
% By heat between rollers, and
Heat setting was performed in a heating box heated to 25 ° C. while relaxing 25% of the total stretching amount to obtain a composite microporous hollow fiber membrane precursor.
次に、エチレン含有量32モル％のエチレン−ビニルア
ルコール共重合体（ソアノールDC3203、日本合成化学株
式会社製）を70℃のエタノール／水＝40/60vol％混合溶
液に1.8重量％溶解した親水性共重合体剤溶液を調整し
た。この親水性共重合体溶液中に上記のプレカーサーを
150秒間浸漬した後複合中空糸を引き上げ、ガイドによ
り該複合中空糸表面に過剰に付着した親水化剤溶液の一
部を絞り落とした。引き続き、エタノール蒸気濃度40vo
l％、60℃の雰囲気中に立上げ角度90°で立上げ、360秒
間滞在させてプレカーサーの微小空孔内表面に親水化剤
を均一付着させた後、60℃の熱風にて溶剤を乾燥した。
得られた親水化中空糸膜のエチレン−ビニルアルコール
共重合体の付着率は8.7重量％であった。Next, 1.8% by weight of an ethylene / vinyl alcohol copolymer (Soarnol DC3203, manufactured by Nippon Synthetic Chemical Co., Ltd.) having an ethylene content of 32 mol% was dissolved in a mixed solution of ethanol / water = 40/60 vol% at 70 ° C. by 1.8 wt%. A solution of the copolymer agent was prepared. In the hydrophilic copolymer solution, the precursor described above was added.
After immersion for 150 seconds, the composite hollow fiber was pulled up, and a part of the hydrophilizing agent solution excessively attached to the surface of the composite hollow fiber was squeezed out by a guide. Continue with ethanol vapor concentration of 40 vo
l%, rise at an angle of 90 ° in an atmosphere of 60 ° C, leave it for 360 seconds to uniformly adhere the hydrophilizing agent to the inside surface of the micropores of the precursor, and then dry the solvent with 60 ° C hot air did.
The adhesion ratio of the ethylene-vinyl alcohol copolymer to the obtained hydrophilic hollow fiber membrane was 8.7% by weight.
得られた複合微多孔質中空糸膜を走査型電子顕微鏡に
て観察したところ、該複合微多孔質中空糸膜の内外表面
及び微孔内表面はエチレン−ビニルアルコール共重合体
の薄膜で均一に覆われており、内層（ｂ層）の微孔のフ
ィブリル束間の平均距離は0.33μ、外層（ａ層）の微孔
のフィブリル束間の平均距離は0.17μであった。このと
き、孔径比はDb/Da＝1.94、分離機能層である外層の膜
厚は10μｍであった。得られた膜の透過型電子顕微鏡写
真を第１図に示すと共に、得られた膜の膜特性を表１に
示す。When the obtained composite microporous hollow fiber membrane was observed with a scanning electron microscope, the inner and outer surfaces and the inner surface of the micropores of the composite microporous hollow fiber membrane were uniformly formed with a thin film of ethylene-vinyl alcohol copolymer. The average distance between the fibril bundles of the pores in the inner layer (layer b) was 0.33 μm, and the average distance between the fibril bundles of the pores in the outer layer (layer a) was 0.17 μm. At this time, the pore size ratio was Db / Da = 1.94, and the thickness of the outer layer serving as the separation function layer was 10 μm. FIG. 1 shows a transmission electron micrograph of the obtained film, and Table 1 shows the film characteristics of the obtained film.
〈実施例２〉 密度0.968g/cm3、MI値0.35の高密度ポリエチレン（BU
004F、三菱化成株式会社製）67重量％と、密度0.962g/c
m3、MI値0.35の高密度ポリエチレン（BT004、三菱化成
株式会社製）33重量％とを二軸押出機により温度180℃
にて溶融混練し、密度0.966g/cm3、MI値0.35のブレンド
ポリマーを得た。Example 2 High-density polyethylene (BU having a density of 0.968 g / cm 3 and an MI value of 0.35)
004F, manufactured by Mitsubishi Chemical Corporation) 67% by weight and density 0.962g / c
m 3 , 33% by weight of high-density polyethylene having an MI value of 0.35 (BT004, manufactured by Mitsubishi Kasei Corporation) at a temperature of 180 ° C. by a twin-screw extruder.
To obtain a blend polymer having a density of 0.966 g / cm 3 and an MI value of 0.35.
次に、このブレンドポリマーをａ層形成用ポリマーと
して、上記の密度0.968g/cm3、MI値0.35の高密度ポリエ
チレンをｂ層形成用ポリマーとして同心円状に配置され
た二つの円管状の吐出口を有する中空糸製造用ノズルを
用いて吐出温度180℃、巻取速度35m/分にて溶融紡糸し
た。このとき、外側の吐出口からブレンドポリマー、内
側の吐出口から前記の高密度ポリエチレンをそれぞれ吐
出量比1/5、全体の吐出量7.5cc/分．吐出口、吐出線速
度57cm/分、ドラフト比75となるように吐出した。さら
にノズルから吐出された糸に温度20℃、風速0.5m/秒の
冷却風を糸の周囲に均一に流しながら巻取り、未延伸複
合中空糸を得た。Next, two circular discharge ports concentrically arranged using the blend polymer as the polymer for forming the a layer and the high density polyethylene having the density of 0.968 g / cm 3 and the MI value of 0.35 as the polymer for forming the b layer. Was spun at a discharge temperature of 180 ° C. and a take-up speed of 35 m / min using a hollow fiber production nozzle having At this time, the blended polymer was discharged from the outer discharge port, and the high-density polyethylene was discharged from the inner discharge port at a discharge rate ratio of 1/5, and the total discharge rate was 7.5 cc / min. Discharge was performed at a discharge port, a discharge linear velocity of 57 cm / min, and a draft ratio of 75. Further, the yarn discharged from the nozzle was wound while cooling air at a temperature of 20 ° C. and a wind speed of 0.5 m / sec was uniformly flowed around the yarn to obtain an undrawn composite hollow fiber.
得られた未延伸中空糸をボビンに巻いたまま、125℃
に加熱した空気中で16時間熱処理した。さらにこのアニ
ール処理糸を30℃に保たれたローラー間で16％冷延伸
し、引き続いて119℃に加熱された加熱炉中で総延伸量
が400％になるようにローラー間熱延伸を行い、さらに1
23℃に加熱した加熱炉中で定長のまま熱セットを行い、
二層よりなる複合微多孔質中空糸膜プレカーサーを得
た。With the obtained undrawn hollow fiber wound on a bobbin, 125 ° C
Heat treatment for 16 hours in heated air. Further, this annealed yarn is cold-drawn between rollers maintained at 30 ° C by 16%, and subsequently subjected to hot-rolling between rollers in a heating furnace heated to 119 ° C so that the total drawn amount becomes 400%. One more
Perform heat setting with a fixed length in a heating furnace heated to 23 ° C,
A composite microporous hollow fiber membrane precursor consisting of two layers was obtained.
次に、エチレン含有量32モル％のエチレン−ビニルア
ルコール共重合体（ソアノールDC3203、日本合成化学株
式会社製）を70℃のエタノール／水＝40/60vol％混合溶
液に2.0重量％溶解した親水性共重合体剤溶液を調整し
た。この親水性共重合体溶液中に上記のプレカーサーを
30秒間浸漬した後、プレカーサーを引き上げ、ガイドに
より該プレカーサー表面に過剰に付着した親水化剤溶液
の一部を絞り落とした。引き続き、エタノール蒸気濃度
40vol％、60℃の雰囲気中に立上げ角度90°で立上げ、8
0秒間滞在させて複合中空糸の微小空孔内表面に親水化
剤を均一付着させた後、70℃の熱風にて溶剤を乾燥し
た。その時のエチレン−ビニルアルコール共重合体の付
着率は10.5重量％であった。Next, a hydrophilicity obtained by dissolving 2.0% by weight of an ethylene-vinyl alcohol copolymer (Soarnol DC3203, manufactured by Nippon Synthetic Chemical Co., Ltd.) having an ethylene content of 32 mol% in a mixed solution of ethanol / water = 40/60 vol% at 70 ° C A solution of the copolymer agent was prepared. In the hydrophilic copolymer solution, the precursor described above was added.
After immersion for 30 seconds, the precursor was pulled up, and a part of the hydrophilizing agent solution excessively attached to the surface of the precursor was squeezed out by a guide. Continue with ethanol vapor concentration
Start up at an angle of 90 ° in an atmosphere of 40vol%, 60 ° C, 8
After allowing the hydrophilic fiber to uniformly adhere to the inner surface of the micropores of the composite hollow fiber by allowing it to stay for 0 second, the solvent was dried with hot air at 70 ° C. At that time, the adhesion ratio of the ethylene-vinyl alcohol copolymer was 10.5% by weight.
得られた複合微多孔質中空糸膜を走査型電子顕微鏡に
て観察したところ、該複合微多孔質中空糸膜の内外表面
及び微孔内表面はエチレン−ビニルアルコール共重合体
の薄膜で均一に覆われており、内層中の微孔のミクロフ
ィブリル束間の平均距離は0.54μｍ、外層中の微孔のミ
クロフィブリル束間の平均距離は0.35μｍであった。こ
のとき、孔径比はDb/Da＝1.54、分離機能層である外層
の膜厚は８μｍであった。透過型電子顕微鏡写真を第２
図に示すと共に、得られた膜の膜特性を表１に示す。When the obtained composite microporous hollow fiber membrane was observed with a scanning electron microscope, the inner and outer surfaces and the inner surface of the micropores of the composite microporous hollow fiber membrane were uniformly formed with a thin film of ethylene-vinyl alcohol copolymer. Covered, the average distance between microfibril bundles of micropores in the inner layer was 0.54 μm, and the average distance between microfibril bundles of micropores in the outer layer was 0.35 μm. At this time, the pore size ratio was Db / Da = 1.54, and the thickness of the outer layer serving as the separation function layer was 8 μm. 2nd transmission electron micrograph
As shown in the figure, the film properties of the obtained film are shown in Table 1.
〈実施例３〉 同心円状に配置された３つの円管状の吐出口を有する
中空糸製造用ノズルを用いて中間層の吐出口からａ層形
成用ポリマーとして密度0.965g/m3、MI値0.9の高密度ポ
リエチレン（HY01、出光化学株式会社製）を吐出量0.37
5g/分で、また、外、内層側の吐出口からｂ層形成用ポ
リマーとして密度0.968g/cm3,MI値5.5の高密度ポリエチ
レン（Hizex 2200 J）を吐出量7.5g/分で吐出した。そ
の時の吐出温度は160℃であり、100m/分の巻取速度で巻
き取った。<Example 3> Using a hollow fiber manufacturing nozzle having three concentrically arranged tubular discharge ports, a density of 0.965 g / m 3 and an MI value of 0.9 were obtained from the discharge port of the intermediate layer as a polymer for forming the a layer. Of high density polyethylene (HY01, manufactured by Idemitsu Chemical Co., Ltd.) 0.37
A high-density polyethylene (Hizex 2200 J) having a density of 0.968 g / cm 3 and an MI value of 5.5 was discharged from the outer and inner layer side discharge ports at a discharge rate of 5 g / min. . The discharge temperature at that time was 160 ° C., and the film was wound at a winding speed of 100 m / min.
得られた未延伸中空糸をボビンに巻いたまま空気中で
115℃で12時間熱処理を行った。さらに、この熱処理糸
を30℃以下に保たれたローラー間で80％冷延伸し、引き
続いて107℃に加熱された加熱炉中で総延伸量が400％に
なるようにローラー間熱延伸を行い、さらに120℃に加
熱した加熱炉中で総延伸量の25％緩和させた状態で熱セ
ットを行い、複合微多孔質膜プレカーサーを得た。In the air while winding the obtained undrawn hollow fiber around the bobbin
Heat treatment was performed at 115 ° C. for 12 hours. Further, the heat-treated yarn is cold-drawn by 80% between rollers maintained at 30 ° C or lower, and subsequently subjected to hot-rolling between rollers in a heating furnace heated to 107 ° C so that the total drawn amount becomes 400%. Then, heat setting was performed in a heating furnace heated to 120 ° C. with the total stretching amount relaxed by 25% to obtain a composite microporous membrane precursor.
得られた複合微多孔質膜プレカーサーを16本合糸し、
70℃に維持したエチレン−ビニルアルコール共重合体
（エチレン含量44モル％）1.8重量％溶液（溶剤エタノ
ール／水＝75/25vol％）に30秒浸漬後、セラミックガイ
ドにより該多層複合膜表面に過剰に付着した共重合体溶
液の一部を絞り落とした後、60℃のエタノール蒸気濃度
約40vol％の雰囲気中に立上げ角度90°で立上げ、80秒
間滞在させ、次いで55℃の熱風にて乾燥し、連続的に親
水化処理された親水性微多孔質膜を得た。16 obtained composite microporous membrane precursors are plied,
After immersing for 30 seconds in a 1.8% by weight solution (solvent ethanol / water = 75 / 25vol%) of an ethylene-vinyl alcohol copolymer (ethylene content: 44 mol%) maintained at 70 ° C., excess was applied to the surface of the multilayer composite film by a ceramic guide. After squeezing a part of the copolymer solution adhered to the sample, it was started at a rising angle of 90 ° in an atmosphere of ethanol vapor concentration of about 40vol% at 60 ° C, allowed to stay for 80 seconds, and then heated with 55 ° C hot air. A hydrophilic microporous membrane which was dried and continuously subjected to a hydrophilic treatment was obtained.
得られた膜の膜特性を表１に示す。 Table 1 shows the film properties of the obtained film.
〈実施例４〉 熱延伸温度を113℃とした以外は実施例１と同様の条
件で親水性微多孔質膜を作成した。<Example 4> A hydrophilic microporous membrane was prepared under the same conditions as in Example 1 except that the heat stretching temperature was 113 ° C.
得られた膜の膜特性を表１に示す。 Table 1 shows the film properties of the obtained film.
〈実施例５〉 同心円状に配置された二つの円管状の吐出口を有する
ノズルの外側の吐出口からｂ層形成用ポリマーとして密
度0.968g/cm3、MI値5.5の高密度ポリエチレン（Hizex 2
200 J、三井石油化学株式会社製）を、内側の吐出口か
らａ層形成用ポリマーとして密度0.960g/cm3−MI値0.9
のポリエチレン（Nissan 2010、日産化学工業株仕会社
製）をそれぞれ吐出量比10/1、吐出線速度5.3cm/分、ド
ラフト比3860、吐出温度170℃にて吐出した。さらにノ
ズルから吐出された糸に温度16℃、風速1.0m/秒の冷却
風を糸の周囲に均一に流しながら巻取速度205m/分にて
巻取り、未延伸複合中空糸を得た。<Example 5> A high-density polyethylene (Hizex 2) having a density of 0.968 g / cm 3 and an MI value of 5.5 as a polymer for forming a layer b was formed from the outer outlet of a nozzle having two concentrically arranged tubular outlets.
200 J, manufactured by Mitsui Petrochemical Co., Ltd.) was supplied from the inner discharge port as a polymer for forming the a layer at a density of 0.960 g / cm 3 -MI value 0.9.
(Nissan 2010, manufactured by Nissan Chemical Industries, Ltd.) was discharged at a discharge rate of 10/1, a discharge linear velocity of 5.3 cm / min, a draft ratio of 3860, and a discharge temperature of 170 ° C. Further, the yarn discharged from the nozzle was wound at a winding speed of 205 m / min while uniformly flowing cooling air at a temperature of 16 ° C. and a wind speed of 1.0 m / sec around the yarn to obtain an undrawn composite hollow fiber.
得られた未延伸糸を115℃に加熱した空気中で定長の
まま12時間アニール処理を行った。さらに、このアニー
ル処理糸を30℃に保たれたローラー間で80％冷延伸し、
引き続いて117℃に加熱された加熱函中で総延伸量が350
％になるようにローラー間熱延伸を行い、さらに、115
℃に加熱した加熱炉中で定長にて１分間の熱セットを行
い、複合微多孔質中空糸膜プレカーサーを得た。このプ
レカーサーを実施例１と同一の条件にて親水化処理を行
った。The obtained undrawn yarn was annealed in air heated at 115 ° C. for 12 hours while keeping the fixed length. Furthermore, this annealed yarn is cold-drawn by 80% between rollers maintained at 30 ° C.
Subsequently, the total stretching amount was 350 in a heating box heated to 117 ° C.
% By heat between rollers, and
Heat setting was performed for 1 minute at a constant length in a heating furnace heated to ℃ to obtain a composite microporous hollow fiber membrane precursor. This precursor was subjected to a hydrophilic treatment under the same conditions as in Example 1.
得られた複合微多孔質中空糸膜の膜特性を表１に示
す。Table 1 shows the membrane characteristics of the obtained composite microporous hollow fiber membrane.
〈実施例６〉 密度0.961g/cm3、MI値0.25の高密度ポリエチレン（63
00、東ソー株式会社製）70重量％と、密度0.957g/cm3、
MI値0.20の低密度ポリエチレン（6200、東ソー株式会社
製）30重量％とを二軸押出機により温度200℃にて溶融
混練し、密度0.959g/cm3、MI値0.23のブレンドポリマー
を得た。次に、このブレンドポリマーをａ層形成用ポリ
マーとして、上記の密度0.961g/cm3、MI値0.25の高密度
ポリエチレンをｂ層形成用ポリマーとして同心円状に配
置された二つの円管状の吐出口を有するノズルを用い
て、吐出温度200℃、巻取速度35m/分にて溶融紡糸し
た。このとき、外側の吐出口からブレンドポリマー、内
側の吐出口から密度0.961g/cm3のポリエチレンをそれぞ
れ吐出量比1/6、吐出線速度57cm/分、ドラフト比75とな
るように吐出した。さらにノズルから吐出された糸に温
度30℃、風速0.5m/秒の冷却風を糸の周囲に均一に流し
ながら巻取り、未延伸複合中空糸を得た。この未延伸複
合中空糸を実施例２と同一の条件にて、アニール処理、
延伸処理、親水化処理を行い、複合微多孔質中空膜を得
た。<Example 6> A high-density polyethylene having a density of 0.961 g / cm 3 and an MI value of 0.25 (63
00, manufactured by Tosoh Corporation) 70% by weight, density 0.957g / cm 3 ,
30% by weight of low-density polyethylene (6200, manufactured by Tosoh Corporation) having an MI value of 0.20 was melt-kneaded at a temperature of 200 ° C. by a twin-screw extruder to obtain a blend polymer having a density of 0.959 g / cm 3 and an MI value of 0.23. . Next, two tubular discharge ports concentrically arranged using the blend polymer as the polymer for forming the a layer and the high density polyethylene having the density of 0.961 g / cm 3 and the MI value of 0.25 as the polymer for forming the b layer. Was melt spun at a discharge temperature of 200 ° C. and a winding speed of 35 m / min. At this time, a blended polymer was discharged from the outer discharge port, and polyethylene having a density of 0.961 g / cm 3 was discharged from the inner discharge port at a discharge rate of 1/6, a discharge linear velocity of 57 cm / min, and a draft ratio of 75, respectively. Further, the yarn discharged from the nozzle was wound while cooling air at a temperature of 30 ° C. and a wind speed of 0.5 m / sec was uniformly flowed around the yarn to obtain an undrawn composite hollow fiber. The undrawn composite hollow fiber was annealed under the same conditions as in Example 2,
A stretching treatment and a hydrophilic treatment were performed to obtain a composite microporous hollow membrane.
〈実施例７〉 実施例４と同様のノズルを用い内層にｂ層形成用ポリ
マーとして密度0.91g/cm3、MI値1.0のポリプロピレン
を、外層にａ層形成用ポリマーとして密度0.965g/cm3、
MI値0.9の高密度ポリエチレンをそれぞれ内層吐出量1.1
g/分、外層吐出量22.5g/分で吐出した。その時の吐出温
度は210℃であり、30m/分の巻取速度で巻取った。それ
以外は、実施例１と同様にして熱処理、延伸を行い、複
合微多孔質膜プレカーサーを得た。<Example 7> Using the same nozzle as in Example 4, the inner layer was made of polypropylene having a density of 0.91 g / cm 3 and an MI value of 1.0 as the polymer for forming the b layer, and the outer layer was made of 0.965 g / cm 3 as the polymer for forming the a layer. ,
High-density polyethylene with MI value 0.9
g / min and the outer layer ejection rate was 22.5 g / min. The discharge temperature at that time was 210 ° C., and winding was performed at a winding speed of 30 m / min. Except for this, heat treatment and stretching were performed in the same manner as in Example 1 to obtain a composite microporous membrane precursor.
得られたプレカーサーを16本合糸し、70℃に維持した
エチレン−ビニルアルコール共重合体（エチレン含量32
モル％）1.8重量％溶液（溶剤エタノール／水＝40/60vo
l％）に30秒浸漬後、セラミックガイドにより該多層複
合膜表面に過剰に付着した共重合体溶液の一部を絞り落
とした後、60℃のエタノール蒸気濃度約40vol％の雰囲
気中に立上げ角度90°で立上げ、360秒間滞在させ、次
いで55℃の熱風にて乾燥し、連続的に親水化処理された
複合微多孔質中空糸膜を得た。Sixteen of the obtained precursors were plied, and an ethylene-vinyl alcohol copolymer (ethylene content 32
(Mol%) 1.8% by weight solution (solvent ethanol / water = 40 / 60vo)
l%) for 30 seconds, and a part of the copolymer solution excessively adhered to the surface of the multilayer composite film is squeezed out by a ceramic guide, and then started up in an atmosphere of ethanol vapor concentration of about 40 vol% at 60 ° C. The composite microporous hollow fiber membrane was started up at an angle of 90 °, allowed to stay for 360 seconds, dried with hot air at 55 ° C, and continuously subjected to hydrophilic treatment.
得られた複合微多孔質中空糸膜の膜性能を表１に示
す。Table 1 shows the membrane performance of the obtained composite microporous hollow fiber membrane.
〈実施例８〉 外層を形成するａ層形成用ブレンドポリマーのブレン
ド比をBU004F:BT004＝50:50重量％としたこと以外は実
施例２と同じ条件で複合微多孔質中空糸膜を作成した。Example 8 A composite microporous hollow fiber membrane was prepared under the same conditions as in Example 2 except that the blend ratio of the blend polymer for forming the a layer forming the outer layer was BU004F: BT004 = 50: 50% by weight. .
得られた複合微多孔質中空糸膜の膜特性を表１に示
す。Table 1 shows the membrane characteristics of the obtained composite microporous hollow fiber membrane.
〈実施例９〉 外層を形成するａ層形成用ブレンドポリマーのブレン
ド比をBU004F:BT004＝33:67重量％としたこと以外は実
施例２と同じ条件で複合微多孔質中空糸膜を作成した。<Example 9> A composite microporous hollow fiber membrane was prepared under the same conditions as in Example 2 except that the blend ratio of the blend polymer for forming the a layer forming the outer layer was BU004F: BT004 = 33:67 wt%. .
得られた複合微多孔質中空糸膜の膜特性を表１に示
す。Table 1 shows the membrane characteristics of the obtained composite microporous hollow fiber membrane.
〈実施例10〉 紡糸における外側と内側の吐出比を1/4、全体の吐出
量を3.0cc/分．吐出口とした以外は実施例２と同じ条件
で複合微多孔質中空糸膜を作成した。<Example 10> The discharge ratio between the outer side and the inner side in spinning was 1/4, and the overall discharge amount was 3.0 cc / min. A composite microporous hollow fiber membrane was prepared under the same conditions as in Example 2 except that the discharge port was used.
得られた複合微多孔質中空糸膜の膜特性を表１に示
す。Table 1 shows the membrane characteristics of the obtained composite microporous hollow fiber membrane.
比較例１ 一つの円管状の吐出口を有する中空糸製造用ノズルを
用いて、密度0.968g/cm3、MI値5.5の高密度ポリエチレ
ンを吐出量7.8g/分で吐出した。その時の吐出温度は160
℃であり、100m/分の巻取速度で巻取った。Comparative Example 1 A high-density polyethylene having a density of 0.968 g / cm 3 and an MI value of 5.5 was discharged at a discharge rate of 7.8 g / min using a hollow fiber manufacturing nozzle having one circular discharge port. The discharge temperature at that time is 160
° C and a winding speed of 100 m / min.
得られた未延伸糸をボビンに巻いたまま空気中で115
℃で12時間熱処理を行った。さらに、この熱処理糸を30
℃以下に保たれたローラー間で80％冷延伸し、引き続い
て95℃に加熱された加熱炉中で総延伸量が300％になる
ようにローラー間熱延伸を行い、さらに120℃に加熱し
た加熱炉中で総延伸量の25％緩和させた状態で熱セット
を行い多孔質膜を得た。The undrawn yarn obtained is wound in a bobbin in air 115
Heat treatment was performed at 12 ° C. for 12 hours. In addition, 30
80% cold stretching between rollers kept at or below ℃, followed by hot stretching between rollers in a heating furnace heated to 95 ° C so that the total stretching amount was 300%, and further heated to 120 ° C Heat setting was performed in a heating furnace with 25% of the total stretching amount relaxed to obtain a porous film.
親水化処理工程は実施例１と全く同様にして行った。 The hydrophilization process was performed in exactly the same manner as in Example 1.
得られた微多孔質中空糸膜の膜特性を表１に示す。 Table 1 shows the membrane characteristics of the obtained microporous hollow fiber membrane.
比較例２ 熱延伸を107℃とした以外は比較例１と全く同様にし
て微多孔質中空糸膜を得た。Comparative Example 2 A microporous hollow fiber membrane was obtained in exactly the same manner as in Comparative Example 1 except that the heat stretching was performed at 107 ° C.
得られた微多孔質膜の膜特性を表１に示す。 Table 1 shows the membrane characteristics of the obtained microporous membrane.
比較例３ 熱延伸を110℃、総延伸量を400％とした以外は比較例
１と全く同様にして微多孔質膜を得た。Comparative Example 3 A microporous film was obtained in exactly the same manner as in Comparative Example 1 except that the hot stretching was 110 ° C. and the total stretching amount was 400%.
得られた微多孔質膜の膜特性を表１に示す。 Table 1 shows the membrane characteristics of the obtained microporous membrane.
比較例４ 比較例１と同様のノズルを用いて密度0.91g/cm3、MI
値1.0のポリプロピレンを吐出量9.0g/分、吐出温度200
℃で吐出し、580m/分の巻取速度で巻取った。Comparative Example 4 Using the same nozzle as in Comparative Example 1, the density was 0.91 g / cm 3 ,
Discharge rate of polypropylene with value 1.0 is 9.0 g / min, discharge temperature is 200
C. and discharged at a winding speed of 580 m / min.
得られた未延伸糸を30℃以下に保たれたローラー間で
26％冷延伸し、引き続いて140℃に加熱された加熱炉中
で総延伸量が122％になるようにローラー間熱延伸を行
い、さらに143℃に加熱した加熱炉中で総延伸量の22％
緩和させた状態で熱セットを行い微多孔質膜プレカーサ
ーを得た。The obtained undrawn yarn is held between rollers maintained at 30 ° C or less.
Cold stretching was performed by 26%, followed by hot stretching between rollers in a heating furnace heated to 140 ° C. so that the total stretching amount was 122%, and then 22% of the total stretching amount in a heating furnace heated to 143 ° C. %
Heat setting was performed in a relaxed state to obtain a microporous membrane precursor.
親水化処理工程は実施例１と全く同様にして行った。 The hydrophilization process was performed in exactly the same manner as in Example 1.
得られた微多孔質膜の膜特性を表１に示す。 Table 1 shows the membrane characteristics of the obtained microporous membrane.
産業上の利用可能性 以上のように、本発明にかかる微多孔質膜は、高分
画、高フラックス、かつ、膜強度にも優れた恒久親水性
が付与された親水性複合微多孔質膜であり、また主に小
孔径を有する分離機能層を膜の断面の任意の位置に設定
することができるため、多種多様な被処理液の濾過に適
している。INDUSTRIAL APPLICABILITY As described above, the microporous membrane according to the present invention has a high fractionation, a high flux, and a hydrophilic composite microporous membrane provided with permanent hydrophilicity excellent in membrane strength. In addition, since the separation function layer having a small pore diameter can be set at an arbitrary position in the cross section of the membrane, it is suitable for filtering various kinds of liquids to be treated.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平２−2849（ＪＰ，Ａ) 特開 平１−222766（ＪＰ，Ａ) 特開 昭57−66114（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) B01D 67/00 - 71/82 510 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-2849 (JP, A) JP-A-1-222766 (JP, A) JP-A-57-66114 (JP, A) (58) Field (Int.Cl. 6 , DB name) B01D 67/00-71/82 510
Claims (15)
も片面に補強機能を担う微多孔質層ｂ層を積層したポリ
オレフィン製複合微多孔質膜であり、ａ層及びｂ層の各
層が膜の延伸軸方向に配向した複数のミクロフィブリル
束とミクロフィブリル束の両端において結合するスタッ
クドラメラの結節部にて構成される楕円状の微孔の積層
体にて構成され、該微孔が該複合微多孔質膜の一表面か
ら他表面に向かって連通しており、該微多孔質膜の微孔
を構成するミクロフィブリル束及びスタックドラメラの
結節部が複合微多孔質膜プレカーサー100重量％に対し
て、３〜30重量％の親水性共重合体にて覆われていると
ともに、ａ層中に存在する微孔のミクロフィブリル束間
の平均距離Daと、ｂ層中に存在する微孔のミクロフィブ
リル束間の平均距離Dbの比が1.3≦Db/Da≦15となる範囲
にあることを特徴とするポリオレフィン製複合微多孔質
膜。1. A composite microporous membrane made of polyolefin comprising a microporous layer a having a reinforcing function and a microporous layer b having a reinforcing function laminated on at least one surface of a microporous layer a having a separating function. A plurality of microfibril bundles oriented in the stretching axis direction of the film and a stack of elliptical micropores formed by knot portions of a stack dramella joined at both ends of the microfibril bundle, and the micropores are formed. The composite microporous membrane communicates from one surface to the other surface, and the microfibril bundles and the nodules of the stack dramella that constitute the micropores of the microporous membrane have a composite microporous membrane precursor of 100% by weight. %, The average distance Da between the microfibril bundles of the micropores existing in the layer a and the microparticles existing in the layer b, while being covered with 3 to 30% by weight of the hydrophilic copolymer. Average distance Db between microfibril bundles of pores Polyolefin composite microporous membrane ratio is characterized in that the range to be 1.3 ≦ Db / Da ≦ 15.
均距離Dbが0.2〜1.0μｍであることを特徴とする請求の
範囲第１項記載のポリオレフィン製複合微多孔質膜。2. The polyolefin composite microporous membrane according to claim 1, wherein the average distance Db between the microfibril bundles of the micropores in the layer b is 0.2 to 1.0 μm.
平均距離Lbが、0.4〜4.0μｍであることを特徴とする請
求の範囲第１項又は第２項記載のポリオレフィン製複合
微多孔質膜。3. The polyolefin composite microparticle according to claim 1, wherein the average distance Lb between the knot portions of the stack lamella in the layer b is 0.4 to 4.0 μm. Porous membrane.
が0.05〜1.0μｍであることを特徴とする請求の範囲第
１項記載のポリオレフィン製複合微多孔質膜。4. The composite microporous membrane made of polyolefin according to claim 1, wherein the maximum pore size of the membrane measured by the bubble point method is 0.05 to 1.0 μm.
ール系共重合体であることを特徴とする請求の範囲第１
項記載のポリオレフィン製複合微多孔質膜。5. The method according to claim 1, wherein the hydrophilic copolymer is an ethylene-vinyl alcohol copolymer.
Item 7. The composite microporous membrane made of polyolefin according to Item 1.
ト20〜90モル％、ビニルアルコール・ユニット10〜80モ
ル％、他のモノマー・ユニット50モル％以下なる共重合
体を用いたことを特徴とする請求の範囲第４項記載のポ
リオレフィン製複合微多孔質膜。6. A copolymer comprising 20 to 90 mol% of ethylene units, 10 to 80 mol% of vinyl alcohol units, and 50 mol% or less of other monomer units as a hydrophilic copolymer. The polyolefin composite microporous membrane according to claim 4, wherein
膜であり、その内径が５〜5000μｍ、全膜厚が５〜500
μｍであり、ａ層の膜厚が0.5μｍ以上で、かつ全膜厚
の1/3以下であることを特徴とする請求の範囲第１項か
ら第５項のいずれか１項に記載のポリオレフィン製複合
微多孔質膜。7. The polyolefin composite microporous membrane is a hollow fiber membrane having an inner diameter of 5 to 5000 μm and a total thickness of 5 to 500 μm.
The polyolefin according to any one of claims 1 to 5, wherein the thickness of the layer a is 0.5 µm or more and 1/3 or less of the total film thickness. Composite microporous membrane.
吐出口を有する中空糸製造用ノズルの吐出口の少なくと
も一つの吐出口に補強機能を担う微多孔質層ｂ層形成用
のメルトインデックス値MIbを有するポリオレフィン
を、ｂ層用の片側又は中間に位置する吐出口に分離機能
を担う微多孔質層ａ層形成用のメルトインデックス値MI
aを有するポリオレフィンを、MIa＜MIbなる関係を満足
せしめて供給し、溶融複合紡糸して得た複合膜を延伸し
て開孔し、ａ層及びｂ層が各層の延伸軸方向に配向した
多数のミクロフィブリルとミクロフィブリルの両端にお
いて結合したスタックドラメラの結節部にて構成される
スリット状微孔の積層体にて構成され、当該微孔が膜の
一表面から他表面に渡って貫通している中空糸膜状プレ
カーサーを、親水性共重合体を有機溶剤中に溶解した有
機溶液中に浸漬した後、引き上げ、該有機溶剤の蒸気を
3vol％以上含み、かつ室温ないし該有機溶剤の沸点以下
の雰囲気中に30秒以上滞在させた後、乾燥し、スタック
ドラメラの結節部とミクロフィブリル束とが該プレカー
サーの乾燥重量100重量％に対して３〜30重量％の親水
性共重合体にて覆われた中空糸膜とすることを特徴とす
るポリオレフィン製複合微多孔質中空糸膜の製法。8. A microporous layer b layer for forming at least one of the discharge ports of a hollow fiber manufacturing nozzle having two or more concentrically arranged circular pipe discharge ports and having a reinforcing function. The polyolefin having a melt index value MIb of the microporous layer that is responsible for the separation function at the discharge port located on one side or in the middle for the b layer, the melt index value MI for forming the a layer
The polyolefin having a is supplied while satisfying the relationship of MIa <MIb, and the composite membrane obtained by melt-spinning is stretched and opened, and a large number of layers a and b are oriented in the stretching axis direction of each layer. Is composed of a stack of slit-shaped micropores composed of knots of a stack dramella joined at both ends of the microfibrils, and the micropores penetrate from one surface of the film to the other surface. After immersing the hollow fiber membrane-shaped precursor in an organic solution in which a hydrophilic copolymer is dissolved in an organic solvent, pull it up, and remove the vapor of the organic solvent.
After being left in an atmosphere containing at least 3 vol% and at room temperature or below the boiling point of the organic solvent for at least 30 seconds, it is dried, and the nodules of the stack dramella and the microfibril bundle are reduced to a dry weight of 100% by weight of the precursor. A method for producing a composite microporous hollow fiber membrane made of polyolefin, wherein the hollow fiber membrane is covered with 3 to 30% by weight of a hydrophilic copolymer.
吐出口を有する中空糸製造用ノズルの吐出口の少なくと
も一つの吐出口に補強機能を担う微多孔質層ｂ層形成用
の密度ρｂを有するポリオレフィンを、ｂ層用の片側又
は中間に位置する吐出口に分離機能を担う微多孔質層ａ
層形成用の密度ρａを有するポリオレフィンを、ρａ＜
ρｂなる関係を満足せしめて供給し、溶融複合紡糸して
得た複合膜を延伸して開孔し、ａ層及びｂ層が各層の延
伸軸方向に配向した多数のミクロフィブリルとミクロフ
ィブリルの両端において結合したスタックドラメラの結
節部にて構成されるスリット状微孔の積層体にて構成さ
れ、当該微孔が膜の一表面から他表面に渡って貫通して
いる中空糸膜状プレカーサーを、親水性共重合体を有機
溶剤中に溶解した有機溶液中に浸漬した後、引き上げ、
該有機溶剤の蒸気を3vol％以上含み、かつ室温ないし該
有機溶剤の沸点以下の雰囲気中に30秒以上滞在させた
後、乾燥し、スタックドラメラの結節部とミクロフィブ
リル束とが該プレカーサーの乾燥重量100重量％に対し
て３〜30重量％の親水性共重合体にて覆われた中空糸膜
とすることを特徴とするポリオレフィン製複合微多孔質
中空糸膜の製法。9. A method for forming a microporous layer b layer which has a reinforcing function at least one of the discharge ports of a hollow fiber production nozzle having two or more concentrically arranged tubular discharge ports. Microporous layer a having a function of separating polyolefin having a density of ρb into a discharge port located on one side or in the middle for layer b.
Polyolefin having a density ρa for forming a layer is converted into ρa <
The composite film obtained by melting and spinning the composite film is stretched and opened, and a number of microfibrils in which the a layer and the b layer are oriented in the stretching axis direction of each layer and both ends of the microfibrils are provided. A hollow fiber membrane-like precursor, which is constituted by a laminate of slit-like micropores formed by knot portions of a stack dramella joined in the above, and the micropores penetrate from one surface of the membrane to the other surface. After immersion in an organic solution of a hydrophilic copolymer dissolved in an organic solvent, then lifted up,
After staying in an atmosphere containing at least 3 vol% of the vapor of the organic solvent and at room temperature or lower than the boiling point of the organic solvent for at least 30 seconds, the stack is dried, and the nodules of the stack dramella and the microfibril bundle form the precursor of the precursor. A method for producing a composite microporous hollow fiber membrane made of polyolefin, characterized in that the hollow fiber membrane is covered with a hydrophilic copolymer of 3 to 30% by weight based on 100% by dry weight.
の吐出口を有する中空糸製造用ノズルの吐出口の少なく
とも一つの吐出口に補強機能を担う微多孔質層ｂ層形成
用の密度ρｂとメルトインデックス値MIbとを有するポ
リオレフィンを、ｂ層用の該吐出口の片側または中間に
位置する吐出口に分離機能を担う微多孔質層ａ層形成用
の密度ρａとメルトインデックス値MIaとを有するポリ
オレフィンを、ρａ＜ρｂ、MIa＜MIbなる関係を満足せ
しめて供給し、溶融複合紡糸して得た複合膜を延伸して
開孔し、ａ層及びｂ層が各層の延伸軸方向に配向した多
数のミクロフィブリルとミクロフィブリルの両端におい
て結合したスタックドラメラの結節部にて構成されるス
リット状微孔の積層体にて構成され、当該微孔が膜の一
表面から他の表面に渡って貫通している中空糸膜状プレ
カーサーを、親水性共重合体を有機溶剤中に溶解した有
機溶液中に浸漬した後、引き上げ、該有機溶剤の蒸気を
3vol％以上含み、かつ室温ないし該有機溶剤の沸点以下
の雰囲気中に30秒以上滞在させた後、乾燥し、スタック
ドラメラの結節部とミクロフィブリル束とが該プレカー
サーの乾燥重量100重量％に対して３〜30重量％の親水
性共重合体にて覆われた中空糸膜とすることを特徴とす
るポリオレフィン製複合微多孔質中空糸膜の製法。10. A microporous layer (b) for forming at least one of the discharge ports of a hollow fiber producing nozzle having two or more concentrically arranged tubular discharge ports and having a reinforcing function. Having a density ρb and a melt index value MIb, a density ρa and a melt index value for forming a microporous layer a layer which has a function of separating a discharge port located on one side or in the middle of the discharge port for the b layer. The polyolefin having MIa is supplied while satisfying the relation of ρa <ρb and MIa <MIb, and the composite membrane obtained by melt-composite spinning is stretched and opened, and the a-layer and the b-layer are stretched in the respective axes. It is composed of a stack of slit-shaped micropores composed of a number of microfibrils oriented in the direction and nodes of a stack dramella joined at both ends of the microfibrils, and the micropores are formed from one surface of the film to another. Across the surface The hollow fiber membrane precursor which has passed through, after immersing the hydrophilic copolymer in an organic solution dissolved in an organic solvent, raising the vapor of the organic solvent
After being left in an atmosphere containing at least 3 vol% and at room temperature or below the boiling point of the organic solvent for at least 30 seconds, it is dried, and the nodules of the stack dramella and the microfibril bundle are reduced to a dry weight of 100% by weight of the precursor. A method for producing a composite microporous hollow fiber membrane made of polyolefin, wherein the hollow fiber membrane is covered with 3 to 30% by weight of a hydrophilic copolymer.
水性有機溶剤と水との混合物を用いることを特徴とする
請求の範囲第８項から第10項のいずれか１項に記載のポ
リオレフィン製複合微多孔質中空糸膜の製法。11. The polyolefin product according to claim 8, wherein a hydrophilic organic solvent or a mixture of a hydrophilic organic solvent and water is used as the organic solvent. Manufacturing method of composite microporous hollow fiber membrane.
のアルコールを用いたことを特徴とする請求の範囲第11
項記載のポリオレフィン製複合微多孔質中空糸膜の製
法。12. The method according to claim 11, wherein an alcohol having a boiling point of 100 ° C. or less is used as the hydrophilic organic solvent.
The method for producing a composite microporous hollow fiber membrane made of polyolefin according to the above item.
平均距離Daと、ｂ層中の微孔のミクロフィブリル束間の
平均距離Dbとの比が1.3≦Db/Da≦15なる範囲にあること
を特徴とする、請求の範囲第８項から第10項のいずれか
１項に記載の製法により得られたポリオレフィン製複合
微多孔質中空糸膜。13. A range in which the ratio of the average distance Da between the microfibril bundles of the micropores in the layer a to the average distance Db between the microfibril bundles of the micropores in the layer b is 1.3 ≦ Db / Da ≦ 15. 11. A composite microporous hollow fiber membrane made of polyolefin obtained by the method according to any one of claims 8 to 10, characterized in that:
平均距離Dbが0.2〜１μｍであることを特徴とする、請
求の範囲第８項から第10項のいずれか１項に記載の製法
により得られたポリオレフィン製複合微多孔質中空糸
膜。14. The method according to claim 8, wherein the average distance Db between the microfibril bundles of the micropores in the layer b is 0.2 to 1 μm. Polyolefin composite microporous hollow fiber membrane obtained by the production method.
であり、かつ水の透過速度が0.5l/m2.hr.mmHg以上であ
ることを特徴とする請求の範囲第１項記載のポリオレフ
ィン製複合微多孔質膜。15. The polyolefin according to claim 1, wherein the diameter of the particles that can be blocked is 0.050 μm or more, and the water permeation rate is 0.5 l / m 2 .hr.mmHg or more. Composite microporous membrane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7518723A JP2955779B2 (en) | 1994-01-17 | 1995-01-17 | Polyolefin composite microporous membrane and method for producing the same |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP329894 | 1994-01-17 | ||
| JP6-3298 | 1994-01-17 | ||
| PCT/JP1995/000043 WO1995019219A1 (en) | 1994-01-17 | 1995-01-17 | Composite microporous polyolefin film and process for producing the same |
| JP7518723A JP2955779B2 (en) | 1994-01-17 | 1995-01-17 | Polyolefin composite microporous membrane and method for producing the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2955779B2 true JP2955779B2 (en) | 1999-10-04 |
Family
ID=26336846
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7518723A Expired - Fee Related JP2955779B2 (en) | 1994-01-17 | 1995-01-17 | Polyolefin composite microporous membrane and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2955779B2 (en) |
-
1995
- 1995-01-17 JP JP7518723A patent/JP2955779B2/en not_active Expired - Fee Related
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