JP5292890B2 - Composite hollow fiber membrane - Google Patents
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本発明は、固液分離に用いられる中空糸膜に関する。さらに詳しくは、排水処理、浄水処理、工業用水製造などにおいて、好適に用いられる複合中空糸膜とその製造方法に関する。 The present invention relates to a hollow fiber membrane used for solid-liquid separation. More specifically, the present invention relates to a composite hollow fiber membrane suitably used in waste water treatment, water purification treatment, industrial water production, and the like, and a method for producing the same.
近年、精密濾過または限外濾過用の中空糸膜モジュールが河川水や地下水の除濁、工業用水の清澄化あるは排水の高度処理などの浄水分野に適用されるようになってきた。この分野の中空糸膜モジュールには、透過水の殺菌や膜のバイオファウリング防止の目的で、次亜塩素酸ナトリウムなど殺菌剤を添加したり、膜そのものを酸、アルカリ、塩素、界面活性剤などで薬品洗浄するために優れた耐薬品性能が求められている。また病原性微生物などが透過処理水に混入しない分離特性と、糸切れしない物理的強度が求められる。 In recent years, hollow fiber membrane modules for microfiltration or ultrafiltration have been applied to the water purification field such as turbidity of river water and groundwater, clarification of industrial water, and advanced treatment of wastewater. In order to sterilize the permeated water and prevent biofouling of the membrane, a hollow fiber membrane module in this field is added with a bactericidal agent such as sodium hypochlorite, or the membrane itself is acid, alkali, chlorine, surfactant. Excellent chemical resistance is required for chemical cleaning. In addition, a separation characteristic that pathogenic microorganisms and the like are not mixed in the permeated water and a physical strength that does not break the yarn are required.
この様な特性要求に対して、ポリフッ化ビニリデン樹脂膜が用いられるようになって来た。しかしながらポリフッ化ビニリデン樹脂膜は、膜面が疎水性相互作用により汚染し易いという欠点があり、ポリフッ化ビニリデン樹脂膜の親水化や複合化など耐汚れ性の改善が行われてきた。例えば膜表面に親水化された、細孔の小さい分離機能層と比較的細孔の粗い支持層を形成させた複合中空糸膜が開発されるようになって来た。 Polyvinylidene fluoride resin films have come to be used in response to such characteristic requirements. However, the polyvinylidene fluoride resin film has a drawback that the film surface is easily contaminated by hydrophobic interaction, and the stain resistance has been improved by making the polyvinylidene fluoride resin film hydrophilic or composite. For example, a composite hollow fiber membrane has been developed in which a separation functional layer having a small pore and a support layer having a relatively coarse pore are formed on the membrane surface.
このような複合中空糸膜モジュールで全量濾過を行った場合、濁質分が中空糸膜の外表面に堆積して濾過抵抗を増大させるが、間欠的にエアスクラビングと逆洗圧などの物理洗浄、或いは適宜行う薬品洗浄で再生使用が可能になる。通常のエアスクラビングでは、モジュール容器内の原水中にエアを送気して、中空糸を揺動させ中空糸同士が摺り合うことで堆積した濁質分を剥離させる。しかしながら濁質分の剥離が進むとモジュール容器内の原水濁度が高くなった状態で中空糸を揺動させることになり、さらに濁質分に硬い成分を含むと膜面擦過が起こり易くなる。連続使用で膜ダメージの蓄積が進むと膜欠陥や損傷となって除濁・除菌性能が低下して、長期再生使用が難しくなる場合がある。 When the total amount of filtration is performed with such a composite hollow fiber membrane module, turbid components accumulate on the outer surface of the hollow fiber membrane to increase the filtration resistance, but intermittent physical scrubbing such as air scrubbing and backwash pressure Alternatively, it can be recycled by chemical cleaning as appropriate. In normal air scrubbing, air is fed into the raw water in the module container, the hollow fibers are rocked and the hollow fibers slide against each other, and the accumulated turbid components are peeled off. However, if separation of turbid components proceeds, the hollow fiber is swung while the raw water turbidity in the module container is high, and if the turbid component contains a hard component, membrane surface abrasion is likely to occur. If film damage accumulates through continuous use, it may become a film defect or damage, resulting in poor turbidity and sterilization performance, and it may be difficult to use for a long time.
この様なスクラビング時の不都合に対して、分離機能層を保護した膜構造が考えられる。例えば特許文献１、２では中空糸の内側に分離機能層を形成させた複合中空糸膜が開示されている。しかしながら中空糸膜内側にポリマー溶液をコーティングして分離機能を形成させるもので、膜壁内部に均一にコーティングできない難点がある。また特許文献３には、溶融紡糸で非多孔性の機能層を両側の支持層で挟みこんだ複合中空糸膜が開示されている。しかし、この様な複合中空糸膜は気体分離を目的にしており、浄水処理分野への適用が困難である。一方で浄水処理分野に使用されるポリフッ化ビニリデン系樹脂製の複合中空糸膜の製造方法として、特許文献４，５には２種類のポリフッ化ビニリデン系樹脂溶液を吐出して非溶媒誘起相分離と熱誘起相分離を併用して製造した複合中空糸膜が開示されている。これらは耐薬品性、透水性、機械的特性、耐汚れ性などに優れているものの最外層のエアスクラビング時の耐擦過性は必ずしも十分ではない。
本発明は、上記した外圧型中空糸膜モジュールのエアスクラビング運転時における課題に鑑み、長期に再生使用することが可能な複合中空糸膜、およびその製造方法を提供することを目的とする。 An object of the present invention is to provide a composite hollow fiber membrane that can be regenerated and used for a long period of time, and a method for producing the same, in view of the problems during air scrubbing operation of the external pressure hollow fiber membrane module described above.
上記の目的を達成するための本発明は、以下により構成される。
（１）三次元網目構造の外層と、それに続く緻密な中間層、それを支える球状構造の支持層で形成されることを特徴とする複合中空糸膜であって、三次元網目構造の外層の平均細孔径が０．１μｍ以上１０μｍ以下であり、緻密な中間層の平均細孔径が０．１μｍ未満であり、球状構造を構成する球状の固形分の平均直径が０．１μｍ以上５μｍ以下であることを特徴とする複合中空糸膜。
（２）三次元網目構造の外層と緻密な中間層が非溶媒誘起相分離により形成された構造であり、球状構造の支持層が熱誘起相分離により形成された構造であることを特徴とする（１）に記載の複合中空糸膜。
（３）三次元網目構造の外層、緻密な中間層および球状構造の支持層を構成する樹脂が、ポリエチレン、ポリプロピレン、アクリル樹脂、ポリアクリロニトリル、アクリロニトリル-ブタジエン-スチレン（ＡＢＳ）樹脂、ポリスチレン、アクリロニトリル−スチレン（ＡＳ）樹脂、塩化ビニル樹脂、ポリエチレンテレフタレート、ポリアミド、ポリアセタール、ポリカーボネート、変成ポリフェニレンエーテル、ポリフェニレンスルフィド、ポリフッ化ビニリデン、ポリアミドイミド、ポリエーテルイミド、ポリスルホン、ポリエーテルスルホンおよびフッ化ビニル、四フッ化エチレン、六フッ化プロピレン、三フッ化塩化エチレンから選ばれた１種類以上とフッ化ビニリデンとの共重合体からなる群から選ばれる少なくとも一つを含むことを特徴とする（１）または（２）に記載の複合中空糸膜。
（４）３重管状紡糸ノズルを用い、内層スリットから球状構造を形成する樹脂溶液Ａを、外層スリットから中間層を形成する樹脂溶液Ｂを、中心パイプから内部凝固液を、共に同心円状に押し出し、外部凝固液中で冷却して凝固させる工程と、溶媒を抜く工程と、得られた複合中空糸膜状物にコーティングノズルを用いて三次元網目構造を形成する樹脂溶液Ｃをコーティングして非溶媒誘起相分離させる工程と、溶媒を抜く工程を経ることで製造される複合中空糸膜の製造方法。
（５）４重管状紡糸ノズルを用い、内層スリットから球状構造を形成する樹脂溶液Ａを、中間スリットから中間層を形成する樹脂溶液Ｂを、外層スリットから三次元網目構造を形成する樹脂溶液Ｃを、中心パイプから内部凝固液を、共に同心円状に押し出し、外部凝固液中で冷却して凝固させる工程と、溶媒を抜く工程を経ることで製造される複合中空糸膜の製造方法。
To achieve the above object, the present invention is constituted as follows.
(1) A composite hollow fiber membrane formed by an outer layer of a three-dimensional network structure, a dense intermediate layer that follows, and a support layer of a spherical structure that supports the three-dimensional network structure, The average pore diameter is 0.1 μm or more and 10 μm or less, the average pore diameter of the dense intermediate layer is less than 0.1 μm, and the average diameter of the spherical solid component constituting the spherical structure is 0.1 μm or more and 5 μm or less. A composite hollow fiber membrane characterized by the above.
(2) The outer layer of the three-dimensional network structure and the dense intermediate layer are formed by non-solvent induced phase separation, and the spherical support layer is formed by thermally induced phase separation. The composite hollow fiber membrane according to (1).
(3) The resin constituting the outer layer of the three-dimensional network structure, the dense intermediate layer, and the support layer of the spherical structure is polyethylene, polypropylene, acrylic resin, polyacrylonitrile, acrylonitrile-butadiene-styrene (ABS) resin, polystyrene, acrylonitrile- Styrene (AS) resin, vinyl chloride resin, polyethylene terephthalate, polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polyphenylene sulfide, polyvinylidene fluoride, polyamideimide, polyetherimide, polysulfone, polyethersulfone and vinyl fluoride, tetrafluoride Containing at least one selected from the group consisting of a copolymer of one or more selected from ethylene, propylene hexafluoride, and ethylene trifluoride chloride and vinylidene fluoride Composite hollow fiber membrane according to (1) or (2).
( 4 ) Using a triple tubular spinning nozzle, concentrically extrude resin solution A that forms a spherical structure from the inner slit, resin solution B that forms an intermediate layer from the outer slit, and inner solidified liquid from the center pipe. A step of cooling and solidifying in an external coagulation liquid, a step of removing the solvent, and coating the obtained composite hollow fiber membrane material with a resin solution C that forms a three-dimensional network structure using a coating nozzle. The manufacturing method of the composite hollow fiber membrane manufactured through the process of carrying out a solvent induction phase separation, and the process of removing a solvent.
( 5 ) Using a quadruple tubular spinning nozzle, a resin solution A that forms a spherical structure from the inner slit, a resin solution B that forms an intermediate layer from the intermediate slit, and a resin solution C that forms a three-dimensional network structure from the outer slit A method for producing a composite hollow fiber membrane produced by subjecting an internal coagulating liquid to a concentric shape from a central pipe, cooling the solidified liquid in an external coagulating liquid, and coagulating it.
本発明は、上記した従来の中空糸膜モジュール運転技術における課題に鑑み、中空糸膜の分離機能層を複層化することで、たとえエアスクラビング時に最外層に損傷を受けたとしても、中間緻密層でバックアップすることで分離機能の低下を抑制できる複合中空糸膜、及びその製造方法を提供することを目的とする。 In view of the problems in the conventional hollow fiber membrane module operation technology described above, the present invention has a multilayer separation function layer of the hollow fiber membrane, so that even if the outermost layer is damaged during air scrubbing, the intermediate dense layer It aims at providing the composite hollow fiber membrane which can suppress the fall of a separation function by backing up with a layer, and its manufacturing method.
本発明の複合中空糸膜とその製造方法について、以下に説明する。図１、図２は、本発明の複合中空糸膜の形態を説明するための図面代用走査電子顕微鏡写真である。 The composite hollow fiber membrane of the present invention and the production method thereof will be described below. 1 and 2 are scanning electron micrographs in place of drawings for explaining the form of the composite hollow fiber membrane of the present invention.
図１は、本発明の中空糸膜を構成する膜壁断面構造を示す図面代用写真（１０００倍）である。中空糸膜の構造は、三次元網目構造の外層と、それに続く緻密な中間層、それを支える球状構造の支持層で形成されている。この様な球状構造の支持層に中間層が積層されるものであるから界面では層同士が互いに入り込むことで形成される。つまり球状構造の平均直径が大きくなると球状で構成される間隙が広くなり、相互に層が深く入り組む形で中間層が厚く積層される。 FIG. 1 is a drawing-substituting photograph (1000 ×) showing a cross-sectional structure of the membrane wall constituting the hollow fiber membrane of the present invention. The structure of the hollow fiber membrane is formed by an outer layer of a three-dimensional network structure, a dense intermediate layer that follows, and a support layer of a spherical structure that supports it. Since the intermediate layer is laminated on the support layer having such a spherical structure, the layers are formed by entering each other at the interface. That is, when the average diameter of the spherical structure is increased, the gap formed by the spherical shape is widened, and the intermediate layer is thickly stacked so that the layers are deeply interleaved with each other.
一方で平均直径が小さくなると、間隙が狭くなり界面で相互に入り組んだ構造が浅く形成するために中間層が薄く形成することになる。ここで緻密な中間層とは、平均厚さが１０μｍ以下、より好ましくは５μｍ以下であって、平均細孔径は０．１μｍ未満、より好ましくは０．０５μｍ以下、さらに好ましくは０．０１μｍ以下であることをいう。０．０１μｍ以下であると最も小さいウイルスであるポリオウイルス（約０．０３μｍ）を阻止できるので好ましい。 On the other hand, when the average diameter is reduced, the gap is narrowed, and the interpenetrating structure at the interface is formed shallow, so that the intermediate layer is formed thin. Here, the dense intermediate layer has an average thickness of 10 μm or less, more preferably 5 μm or less, and an average pore diameter of less than 0.1 μm, more preferably 0.05 μm or less, still more preferably 0.01 μm or less. Say something. A thickness of 0.01 μm or less is preferable because poliovirus (about 0.03 μm), which is the smallest virus, can be blocked.
また球状構造からなる支持層の平均厚さは６０μｍ以上５００μｍ以下、より好ましくは１２０μｍ以上３５０μｍ以下であり、球状構造の平均直径は０．１μｍ以上５μｍ以下、より好ましくは０．５μｍ以上３μｍ以下である。平均直径が０．１μｍ未満であると球状で形成する間隙が狭くなり、機械的強度が高くなるが透水性性能が低下する場合がある。また平均直径が５μｍ超えると球状構造で形成される間隙が広くなり透水性が高くなるが、機械的強度が低下する傾向を示す場合がある。支持層の厚さが６０μｍを下回ると外圧による座屈圧力が低下し、５００μｍを超えると透水性能が下がる場合があるので両者のバランスを考慮することが好ましい。ここで球状構造とは、多数の球状もしくは略球状の固形分が、直接もしくは筋状に固形分を介して連結している構造のこという。 The average thickness of the support layer having a spherical structure is 60 μm to 500 μm, more preferably 120 μm to 350 μm, and the average diameter of the spherical structure is 0.1 μm to 5 μm, more preferably 0.5 μm to 3 μm. is there. When the average diameter is less than 0.1 μm, the gap formed in a spherical shape is narrowed and the mechanical strength is increased, but the water permeability may be lowered. On the other hand, when the average diameter exceeds 5 μm, the gap formed by the spherical structure becomes wide and the water permeability increases, but the mechanical strength may tend to decrease. If the thickness of the support layer is less than 60 μm, the buckling pressure due to the external pressure is reduced, and if it exceeds 500 μm, the water permeability may be lowered. Here, the spherical structure means a structure in which a large number of spherical or substantially spherical solid components are connected directly or in a streak shape through the solid components.
また三次元網目構造からなる外層の平均厚さは５μｍ以上６０μｍ以下、より好ましくは５μｍ以上３０μｍ以下であり、三次元構造の平均細孔径が０．１μｍ以上１０μｍ以下である。ここで三次元網目構造とは、固形分が三次元的に網目状に広がっている構造をいう。また三次元網目構造は網を形成する固形分に仕切られた細孔およびボイドを有する。三次元網目構造からなる外層は、連続した構造であるが、最表面側には三次元網目構造ではない厚さ２μｍ以下の層を有していてもよい。 The average thickness of the outer layer having a three-dimensional network structure is 5 μm to 60 μm, more preferably 5 μm to 30 μm, and the average pore diameter of the three-dimensional structure is 0.1 μm to 10 μm. Here, the three-dimensional network structure refers to a structure in which the solid content spreads in a three-dimensional network. In addition, the three-dimensional network structure has pores and voids partitioned by solid contents forming a network. The outer layer made of a three-dimensional network structure is a continuous structure, but may have a layer having a thickness of 2 μm or less that is not a three-dimensional network structure on the outermost surface side.
図２は、本発明中空糸の三次元網目構造の外層に続く最表面の形態を示す図面代用写真（３００００倍）である。本発明の複合中空糸膜では、最表面の平均細孔径が０．０１μｍ以上１μｍ以下であり、好ましくは０．０１μｍ以上０．２μｍ以下、さらに好ましくは０．０１μｍ以上０．１μｍ以下である。最表面の平均細孔径が１μｍを超えると膜ファウリングが発生し易くなり、０．０１μｍを下回ると透水性が低下する傾向がある。 FIG. 2 is a drawing substitute photograph (30000 times) showing the form of the outermost surface following the outer layer of the three-dimensional network structure of the hollow fiber of the present invention. In the composite hollow fiber membrane of the present invention, the average pore diameter on the outermost surface is 0.01 μm or more and 1 μm or less, preferably 0.01 μm or more and 0.2 μm or less, more preferably 0.01 μm or more and 0.1 μm or less. If the average pore diameter on the outermost surface exceeds 1 μm, membrane fouling tends to occur, and if it is less than 0.01 μm, the water permeability tends to decrease.
本発明の複合中空糸膜の製造方法は、例えば一般的に用いられる２重管状紡糸ノズルで支持膜を製造した後、分離機能層を多層コーティングする方法、或いは複層ノズルを用いて同時に成形樹脂を押し出すことで複層化するものであり、これらの製造方法を組み合わせることでも製造することが可能である。よって以下に例示する製造方法に限定されるものではない。 The method for producing a composite hollow fiber membrane of the present invention includes, for example, a method in which a support membrane is produced with a commonly used double tubular spinning nozzle and then a multilayer coating is applied to a separation functional layer, or a molding resin is simultaneously produced using a multilayer nozzle It is possible to manufacture by combining these manufacturing methods. Therefore, it is not limited to the manufacturing method illustrated below.
本発明の複合中空糸膜の製造方法としては、例えば３重管状紡糸ノズルと、コーティングノズルを併用することで製造することができる。ここで３管状紡糸ノズルとは、円形ノズル内に２重（２層）パイプが挿入された構成で一定間隔の外層スリット、内層スリット、および中心パイプからなる金属製、或いはセラミックス製などの紡糸ノズルをいう。また本発明で用いるコーティングノズルとは、例えば特開２００４−３１４０５９号公報に記載の弾性体で構成されるコーティングノズル、或いは金属やセラミックスで構成される円形ノズルをいう。 As a manufacturing method of the composite hollow fiber membrane of this invention, it can manufacture, for example by using together a triple tubular spinning nozzle and a coating nozzle. Here, the three-tubular spinning nozzle is a spinning nozzle made of a metal or ceramic made of a double (double layer) pipe inserted into a circular nozzle and having an outer layer slit, an inner layer slit, and a center pipe at regular intervals. Say. Moreover, the coating nozzle used by this invention means the coating nozzle comprised by the elastic body of Unexamined-Japanese-Patent No. 2004-314059, for example, or the circular nozzle comprised by a metal or ceramics.
本発明の複合中空糸膜は、３重管状紡糸ノズルを用い、内層スリットから球状構造を形成する樹脂溶液Ａを、外層スリットから中間層を形成する樹脂溶液Ｂを、中心パイプから内部凝固液を、共に同心円状に押し出し、外部凝固液で同時に冷却して凝固させる工程と、溶媒を抜く工程を経て中間層を形成させた複合中空糸膜状物を得る。その後、該複合中空糸膜状物にコーティングノズルを用いて三次元網目構造を形成する樹脂溶液Ｃを塗布した後、凝固させる工程を経ることで製造することができる。 The composite hollow fiber membrane of the present invention uses a triple tubular spinning nozzle, and a resin solution A that forms a spherical structure from the inner slit, a resin solution B that forms an intermediate layer from the outer slit, and an internal coagulating liquid from the center pipe Both are extruded concentrically, cooled simultaneously with an external coagulation liquid, and solidified through a process of removing the solvent to obtain a composite hollow fiber membrane formed with an intermediate layer. Thereafter, the composite hollow fiber membrane can be manufactured by applying a resin solution C that forms a three-dimensional network structure using a coating nozzle and then solidifying the resin solution C.
本発明の複合中空糸膜は、中間層を形成する樹脂溶液Ｂが外部凝固液に接触して非溶媒誘起相分離により中間層（外周）が凝固し、同時に樹脂溶液Ａが冷却による熱誘起相分離により、樹脂溶液Ａ中に核が発生して結晶成長することで球状構造を支持層に形成させる複合中空糸膜状物を得る。この後に、さらに中間層上に三次元網目構造を形成する樹脂溶液Ｃをコーティングノズルで積層して非溶媒誘起相分離させることで、外層を複層化するものである。 In the composite hollow fiber membrane of the present invention, the resin solution B that forms the intermediate layer contacts the external coagulation liquid, and the intermediate layer (periphery) is solidified by non-solvent induced phase separation, and at the same time, the resin solution A is thermally induced by cooling. By separation, nuclei are generated in the resin solution A and crystal growth is performed, thereby obtaining a composite hollow fiber membrane material that forms a spherical structure on the support layer. Thereafter, a resin solution C that forms a three-dimensional network structure on the intermediate layer is further laminated by a coating nozzle and non-solvent induced phase separation is performed to form a multilayered outer layer.
以上の製造方法に加えて、膜壁の空隙の拡大による透水性能向上として延伸を施すことも好適に用いられる。延伸方法としては、中空糸膜を構成する熱可塑性樹脂のガラス転移点より高く、融点より低い温度範囲で好ましくは１．１倍以上４倍以下に延伸を行う。延伸の熱媒としては、液体および気体など温度制御が容易なものから適宜用いることができる。 In addition to the above manufacturing method, stretching is also preferably used as an improvement in water permeability by expanding the voids in the membrane wall. As a stretching method, stretching is preferably performed 1.1 times to 4 times in a temperature range higher than the glass transition point of the thermoplastic resin constituting the hollow fiber membrane and lower than the melting point. As the heat medium for stretching, those that can be easily controlled such as liquid and gas can be used as appropriate.
また本発明の複合中空糸膜は、４重管状紡糸ノズルを用いて製造することでも良い。ここで４重管状紡糸ノズルとは、円形ノズル内に３重（３層）パイプが挿入された構成で一定間隔の外層スリット、中間スリット、内層スリット、および中心パイプからなる金属製、或いはセラミックス製などの紡糸ノズルをいう。この４重管状紡糸ノズルを用い、内層スリットから球状構造を形成する樹脂溶液Ａを、中間スリットから中間層を形成する樹脂溶液Ｂを、外層ノズルから三次元網目構造を形成する樹脂溶液Ｃを、中心パイプから内部凝固液と共に同心円状に押し出し、外部凝固液で同時に冷却して凝固させる工程と、溶媒を抜く工程を経ることで本発明の複合中空糸膜が製造される。 The composite hollow fiber membrane of the present invention may be manufactured using a quadruple tubular spinning nozzle. Here, the quadruple tubular spinning nozzle is a metal or ceramic made of an outer layer slit, an intermediate slit, an inner layer slit, and a center pipe having a constant interval in a configuration in which a triple (three layer) pipe is inserted into a circular nozzle. A spinning nozzle. Using this quadruple tubular spinning nozzle, a resin solution A that forms a spherical structure from the inner layer slit, a resin solution B that forms an intermediate layer from the intermediate slit, and a resin solution C that forms a three-dimensional network structure from the outer layer nozzle, The composite hollow fiber membrane of the present invention is manufactured through a process of concentrically extruding together with the internal coagulating liquid from the center pipe, and simultaneously cooling and solidifying with the external coagulating liquid and a process of removing the solvent.
本発明の複合中空糸膜は、押し出した樹脂溶液Ｃと樹脂溶液Ｂに外部凝固液が浸透して非溶媒誘起相分離により最外層（外周）から凝固が進展し、同時に樹脂溶液Ａが冷却による熱誘起相分離により結晶成長が進展することで膜構造が形成される。この際に樹脂溶液Ａと樹脂溶液Ｂと樹脂溶液Ｃの各供給量を制御し、さらに外部凝固液の非溶媒濃度と冷却温度を制御することにより製造することが可能になる。樹脂溶液Ｂにあって、本発明の中間層を形成するものであれば、非溶媒誘起相分離、或いは熱誘起相分離のどちらが支配的に起こって、膜構造を形成しても構わない。 In the composite hollow fiber membrane of the present invention, the external coagulation liquid penetrates into the extruded resin solution C and resin solution B, and solidification progresses from the outermost layer (outer periphery) by non-solvent induced phase separation, and at the same time, the resin solution A is cooled. A film structure is formed by crystal growth progressing by thermally induced phase separation. At this time, it is possible to manufacture by controlling each supply amount of the resin solution A, the resin solution B, and the resin solution C, and further controlling the non-solvent concentration and the cooling temperature of the external coagulation liquid. As long as it is in the resin solution B and forms the intermediate layer of the present invention, either non-solvent induced phase separation or thermally induced phase separation may occur predominantly to form a film structure.
本発明に使用される樹脂とは、鎖状高分子からなる熱可塑性樹脂をいう。例えばポリエチレン、ポリプロピレン、アクリル樹脂、ポリアクリロニトリル、アクリロニトリル-ブタジエン-スチレン（ＡＢＳ）樹脂、ポリスチレン、アクリロニトリル−スチレン（ＡＳ）樹脂、塩化ビニル樹脂、ポリエチレンテレフタレート、ポリアミド、ポリアセタール、ポリカーボネート、変成ポリフェニレンエーテル、ポリフェニレンスルフィド、ポリフッ化ビニリデン、ポリアミドイミド、ポリエーテルイミド、ポリスルホン、ポリエーテルスルホンおよびこれらの混合物や共重合体が挙げられる。これらと混和可能な他の樹脂および多価アルコールや界面活性剤を５０重量％以下含んでいてもよい。中でも耐薬品性の高いポリフッ化ビニリデン系樹脂が好ましく用いられる。 The resin used in the present invention refers to a thermoplastic resin composed of a chain polymer. For example, polyethylene, polypropylene, acrylic resin, polyacrylonitrile, acrylonitrile-butadiene-styrene (ABS) resin, polystyrene, acrylonitrile-styrene (AS) resin, vinyl chloride resin, polyethylene terephthalate, polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polyphenylene sulfide , Polyvinylidene fluoride, polyamideimide, polyetherimide, polysulfone, polyethersulfone, and mixtures and copolymers thereof. Other resins miscible with these and polyhydric alcohols or surfactants may be contained in an amount of 50% by weight or less. Among them, a polyvinylidene fluoride resin having high chemical resistance is preferably used.
ポリフッ化ビニリデン系樹脂とは、フッ化ビニリデンホモポリマーおよび／またはフッ化ビニリデン共重合体を含有する樹脂を意味し、複数の種類のフッ化ビニリデン共重合体を含有しても構わない。フッ化ビニリデン共重合体は、フッ化ビニリデン残基構造を有するポリマーであり、典型的にはフッ化ビニリデンモノマーとそれ以外のフッ素系モノマーなどとの共重合体である。かかる共重合体としては、例えば、フッ化ビニル、四フッ化エチレン、六フッ化プロピレン、三フッ化塩化エチレンから選ばれた１種類以上とフッ化ビニリデンとの共重合体が挙げられる。また本発明の効果を損なわない程度に、前記フッ素系モノマー以外の例えばエチレンなどのモノマーが共重合されていても良い。 The polyvinylidene fluoride resin means a resin containing a vinylidene fluoride homopolymer and / or a vinylidene fluoride copolymer, and may contain a plurality of types of vinylidene fluoride copolymers. The vinylidene fluoride copolymer is a polymer having a vinylidene fluoride residue structure, and is typically a copolymer of a vinylidene fluoride monomer and other fluorine-based monomers. Examples of the copolymer include a copolymer of vinylidene fluoride and at least one selected from vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, and trifluoroethylene chloride. In addition, a monomer such as ethylene other than the fluorine-based monomer may be copolymerized to such an extent that the effects of the present invention are not impaired.
本発明の球状構造を形成する樹脂溶液Ａとは、前記ポリフッ化ビニリデン系樹脂を２０重量％以上、６０重量％以下に用いる。より好ましくは２５重量％以上、４５重量％以下である。２０重量％以上であると糸の機械的強度が高く、６０重量％以下であると透過性能が向上する。 With the resin solution A forming the spherical structure of the present invention, the polyvinylidene fluoride resin is used in an amount of 20 wt% to 60 wt%. More preferably, it is 25 weight% or more and 45 weight% or less. When it is 20% by weight or more, the mechanical strength of the yarn is high, and when it is 60% by weight or less, the permeation performance is improved.
また本発明の中間層を形成する樹脂溶液Ｂと、三次元網目構造の外層を形成する樹脂溶液Ｃは、前記ポリフッ化ビニリデン系樹脂を用いる場合には、５重量％以上２５重量％以下、より好ましくは１０重量％以上２０重量％以下である。５重量％以上であると外層の機械的強度が向上し、２５重量％以下であると透過性が向上する。なお樹脂溶液Ａ、樹脂溶液Ｂ、及び樹脂溶Ｃに用いる樹脂は、同一の樹脂でも、異なる樹脂でも良い。適宜、製造する中空糸膜の強伸度特性、透過特性、分画阻止性などの諸特性をより広い範囲で調整することができる。樹脂溶液Ｂと樹脂溶液Ｃの溶媒としては前記ポリフッ化ビニリデン系樹脂の良溶媒が好ましい。樹脂溶液Ａの溶媒としては、前記ポリフッ化ビニリデン系樹脂の貧溶媒が好ましい。また樹脂溶液Ｂと樹脂溶液Ｃの溶媒としては、前記ポリフッ化ビニリデン系樹脂の良溶媒、及び５重量％以下の非溶媒を含む良溶媒の混合液が好ましい。 Further, the resin solution B forming the intermediate layer of the present invention and the resin solution C forming the outer layer of the three-dimensional network structure, when the polyvinylidene fluoride resin is used, are 5 wt% or more and 25 wt% or less. Preferably they are 10 weight% or more and 20 weight% or less. When it is 5% by weight or more, the mechanical strength of the outer layer is improved, and when it is 25% by weight or less, the permeability is improved. The resin used for the resin solution A, the resin solution B, and the resin solution C may be the same resin or different resins. As appropriate, various properties such as the strength and elongation properties, the permeability properties, and the fraction blocking properties of the hollow fiber membrane to be produced can be adjusted in a wider range. The solvent for the resin solution B and the resin solution C is preferably a good solvent for the polyvinylidene fluoride resin. As a solvent for the resin solution A, a poor solvent for the polyvinylidene fluoride resin is preferable. Moreover, as a solvent of the resin solution B and the resin solution C, the good solvent of the good solvent containing the good solvent of the said polyvinylidene fluoride type resin and 5 weight% or less nonsolvent is preferable.
ここでポリフッ化ビニリデン系樹脂の貧溶媒としては、例えばシクロヘキサン、イソホロン、γ-ブチロラクトン、メチルイソアミルケトン、フタル酸ジメチル、プロピレングリコールメチルエーテル、プロピレンカーボネート、ジアセトンアルコール、グリセロールトリアセテートなど中鎖長のアルキルケトン、エステル、グリコールエステルおよび有機カーボネート等、及びその混合溶媒が挙げられる。 Examples of the poor solvent for the polyvinylidene fluoride resin include cyclohexane, isophorone, γ-butyrolactone, methyl isoamyl ketone, dimethyl phthalate, propylene glycol methyl ether, propylene carbonate, diacetone alcohol, and glycerol triacetate. Examples include ketones, esters, glycol esters and organic carbonates, and mixed solvents thereof.
前記樹脂の良溶媒としては、例えばＮ-メチル-２-ピロリドン、ジメチルスルホキシド、ジメチルアセトアミド、ジメチルホルムアミド、メチルエチルケトン、アセトン、テロラヒドロフラン、テトラメチル尿素、リン酸トリメチル等の低級アルキルケトン、エステル、アミド等およびその混合溶媒が挙げられる。前記樹脂の非溶媒としては、例えば水、ヘキサン、ペンタン、ベンゼン、トルエン、メタノール、エタノール、四塩化炭素、ｏ−ジクロルベンゼン、トリクロルエチレン、エチレングリコール、ジエチレングリコール、トリエチレングリコール、プロピレングリコール、ブチレングリコール、ペンタンジオール、ヘキサンジオール、低分子量のポリエチレングリコール等の脂肪族炭化水素、芳香族炭化水素、脂肪族多価アルコール、芳香族多価アルコール、塩素化炭化水素、またはその他の塩素化有機液体およびその混合溶媒などが挙げられる。 Examples of the good solvent for the resin include N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylacetamide, dimethylformamide, methyl ethyl ketone, acetone, terahydrofuran, tetramethylurea, trimethyl phosphate, and other lower alkyl ketones, esters, and amides. Etc. and mixed solvents thereof. Examples of the non-solvent for the resin include water, hexane, pentane, benzene, toluene, methanol, ethanol, carbon tetrachloride, o-dichlorobenzene, trichloroethylene, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and butylene glycol. , Pentanediol, hexanediol, low molecular weight polyethylene glycol and other aliphatic hydrocarbons, aromatic hydrocarbons, aliphatic polyhydric alcohols, aromatic polyhydric alcohols, chlorinated hydrocarbons, or other chlorinated organic liquids and their Examples thereof include mixed solvents.
ここで貧溶媒とは、ポリフッ化ビニリデン系樹脂を６０℃以下では５重量％以下しか溶解できないが、６０℃以上かつ樹脂の融点以下で５重量％以上溶解させることができる溶媒と定義する。これに対してポリフッ化ビニリデン系樹脂を６０℃以下でも５重量％以上溶解させることが可能な溶媒が良溶媒であり、また融点まで溶解も膨潤もさせない溶媒が非溶媒である。 Here, the poor solvent is defined as a solvent capable of dissolving 5% by weight or less of a polyvinylidene fluoride-based resin at 60 ° C. or less but not more than 5% by weight at 60 ° C. or more and below the melting point of the resin. In contrast, a solvent capable of dissolving 5% by weight or more of a polyvinylidene fluoride resin at 60 ° C. or less is a good solvent, and a solvent that does not dissolve or swell up to the melting point is a non-solvent.
本発明で用いる内部凝固液としては、樹脂溶液Ａの貧溶媒を７５重量％以上９５重量％以下に非溶媒を２５重量％以下５重量％以上に含む混合溶液が好ましい。内部凝固液中に非溶媒が２５重量％以下５重量％以上にあると中空部を形成する内壁の平滑性が向上する。 The internal coagulation liquid used in the present invention is preferably a mixed solution containing 75% to 95% by weight of the poor solvent of the resin solution A and 25% to 5% by weight of the non-solvent. When the non-solvent is 25 wt% or less and 5 wt% or more in the internal coagulating liquid, the smoothness of the inner wall forming the hollow portion is improved.
本発明で用いる外部凝固液としては、樹脂溶液Ｂと樹脂溶液Ｃに対する非溶媒、或いは樹脂溶液Ｂと樹脂溶液Ｃに対して７０重量％以上の非溶媒と３０重量％以下の貧溶媒、或いは良溶媒から成る混合溶媒を用いることが好ましい。外部凝固液中の非溶媒の割合が７０重量％以上であると樹脂溶液Ａの熱誘起相分離より樹脂溶液Ｂと樹脂溶液Ｃの非溶媒拡散が速やかに起こって外表面が凝固すると共に、樹脂溶液Ａで熱誘起相分離を伴って固化する。外部凝固液の温度は、紡糸ノズルから吐出直後に非溶媒誘起相分離と熱誘起相分離を併用する場合、３０℃以下が好ましく、さらに好ましくは２０℃以下である。一方でコーティングノズルから引き出して用いる場合の温度は、５℃以上、８０℃以下に非溶媒誘起相分離を調整することができる。 As the external coagulation liquid used in the present invention, a non-solvent for the resin solution B and the resin solution C, a non-solvent of 70% by weight or more and a poor solvent of 30% by weight or less for the resin solution B and the resin solution C, or good It is preferable to use a mixed solvent composed of a solvent. When the ratio of the non-solvent in the external coagulation liquid is 70% by weight or more, the non-solvent diffusion between the resin solution B and the resin solution C occurs more rapidly than the heat-induced phase separation of the resin solution A, and the outer surface coagulates. Solidify in solution A with thermally induced phase separation. The temperature of the external coagulation liquid is preferably 30 ° C. or less, more preferably 20 ° C. or less, when both non-solvent induced phase separation and thermally induced phase separation are used immediately after ejection from the spinning nozzle. On the other hand, non-solvent- induced phase separation can be adjusted to a temperature of 5 ° C. or higher and 80 ° C. or lower when used by being pulled out from the coating nozzle.
以下に具体的な実施例を挙げて本発明を説明するが、本発明はこれらの実施例により何ら限定されるものではない。ここでは本発明に関する物性値は以下の方法で測定した。 Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited to these examples. Here, the physical properties related to the present invention were measured by the following methods.
（１）外層の厚さ
走査型電子顕微鏡を用いて、複合中空糸膜の断面を１，０００倍、３,０００倍で写真撮影した際に、外層の厚さを、任意に選んだ１０カ所で測定し、数平均して求めた。
(1) Thickness of the outer layer When the cross section of the composite hollow fiber membrane was photographed at 1,000 times and 3,000 times using a scanning electron microscope, the thickness of the outer layer was arbitrarily selected at 10 locations. The number was measured and averaged.
（２）中間層の厚さ
走査型電子顕微鏡を用いて、複合中空糸膜の断面を３,０００倍で写真撮影し、中間層の厚さを、任意に選んだ１０カ所で測定し、数平均して求めた。
(2) Thickness of the intermediate layer Using a scanning electron microscope, a cross section of the composite hollow fiber membrane was photographed at a magnification of 3,000 times, and the thickness of the intermediate layer was measured at 10 arbitrarily selected locations. Obtained on average.
（３）支持層の厚さ
走査電子顕微鏡を用いて、膜の断面を１００倍、１,０００倍で写真撮影した際に、支持層の厚さを、任意に選んだ１０カ所で測定し、数平均して求めた。
(3) Support layer thickness Using a scanning electron microscope, when the cross section of the film was photographed at 100 times and 1,000 times, the thickness of the support layer was measured at 10 arbitrarily selected locations, Obtained by number average.
（４）最表面の平均細孔径
走査型電子顕微鏡を用いて、複合中空糸膜の表面を６０,０００倍で写真撮影し、任意に選んだ２０カ所の細孔径の直径を測定し、数平均して求めた。
(4) Average pore diameter of outermost surface Using a scanning electron microscope, the surface of the composite hollow fiber membrane was photographed at 60,000 times, and the diameters of 20 arbitrarily selected pore diameters were measured, and the number average And asked.
（５）外層の三次元網目構造の平均細孔径
走査型電子顕微鏡を用いて、複合中空糸膜の断面を６,０００倍で写真撮影し、外層の三次元網目構造が観察される範囲の任意に選んだ２０カ所の細孔径の直径を測定し、数平均して求めた。
(5) Average pore diameter of outer layer three-dimensional network structure Using a scanning electron microscope, the cross-section of the composite hollow fiber membrane was photographed at a magnification of 6,000, and an arbitrary range in which the outer layer three-dimensional network structure was observed The diameters of the 20 pore diameters selected in the above were measured and obtained by number averaging.
（６）中間層の平均細孔径
走査型電子顕微鏡を用いて、複合中空糸膜の断面を６０,０００倍で写真撮影し、中間層の任意に選んだ２０カ所の細孔径の直径を測定し、数平均して求めた。
(6) Average pore diameter of intermediate layer Using a scanning electron microscope, a cross-section of the composite hollow fiber membrane was photographed at 60,000 times, and the diameters of 20 pore diameters arbitrarily selected in the intermediate layer were measured. The number average was obtained.
（７）支持層の球状構造の平均直径
走査型電子顕微鏡を用いて、複合中空糸膜の断面を１０,０００倍で写真撮影し、任意に選んだ２０個の球状構造の直径を測定し、数平均して求めた。
(7) Average diameter of the spherical structure of the support layer Using a scanning electron microscope, the cross-section of the composite hollow fiber membrane was photographed at a magnification of 10,000 times, and the diameters of 20 arbitrarily selected spherical structures were measured. Obtained by number average.
（８）中空糸膜の内径／外径
走査型電子顕微鏡を用いて、複合中空糸膜の断面を５０倍、１００倍で写真撮影し、長径と短径を測定し、数平均して求めた。
(8) Inner diameter / outer diameter of hollow fiber membrane Using a scanning electron microscope, the cross section of the composite hollow fiber membrane was photographed at 50 times and 100 times, the major axis and minor axis were measured, and the number average was obtained. .
（９）エアスクラビング耐久性評価
モジュール容器（内径１０ｃｍ、長さ１００ｃｍ）に中空糸膜１５００本を挿入した中空糸膜モジュールを作製した。次に膜モジュール容器内に５０００ｐｐｍのカオリン水溶液で満たし、容器下部より１００Ｌ／分の空気を連続的に３０日間供給してエアスクラビングを行った。
(9) Air scrubbing durability evaluation A hollow fiber membrane module was prepared by inserting 1500 hollow fiber membranes into a module container (inner diameter 10 cm, length 100 cm). Next, the membrane module container was filled with a 5000 ppm kaolin aqueous solution, and 100 L / min of air was continuously supplied from the bottom of the container for 30 days for air scrubbing.
（１０）阻止性能
スクラビング性耐久評価後の中空糸膜を任意に選んだ箇所から取り出し、中空糸膜４本からなる有効長さ２０ｃｍの小型モジュールを作製し、温度２５℃、濾過差圧１６ｋＰａの条件下に、平均粒径０．３０９μｍのポリスチレンラテックス粒子を分散させた原水を外圧全濾過で３０分間行い、原水と透過水中のラテックス粒子の濃度を波長２３４ｎｍの紫外吸収係数を測定し、その濃度比から阻止性能を求めた。波長２３４ｎｍの紫外吸収係数の測定は、分光光度計（Ｕ-３２００，日立製作所製）を用いた。
(10) Blocking performance The hollow fiber membrane after scrubbing durability evaluation is taken out from an arbitrarily selected location, and a small module having an effective length of 20 cm consisting of four hollow fiber membranes is produced, and the temperature is 25 ° C. and the filtration differential pressure is 16 kPa. Under conditions, raw water in which polystyrene latex particles having an average particle diameter of 0.309 μm are dispersed is subjected to external pressure total filtration for 30 minutes, and the concentration of latex particles in raw water and permeated water is measured for an ultraviolet absorption coefficient at a wavelength of 234 nm. The blocking performance was obtained from the ratio. A spectrophotometer (U-3200, manufactured by Hitachi, Ltd.) was used to measure the ultraviolet absorption coefficient at a wavelength of 234 nm.
（１１）透水性能
中空糸膜４本からなる有効長さ２０ｃｍの小型モジュールを作製し、温度２５℃、濾過差圧１６ｋＰａの条件下で蒸留水を送液して外圧全濾過を３０分間行った時の透過水量（ｍ３）を求めた。次に単位時間（ｈｒ）、単位膜面積（ｍ２）、５０ｋＰａあたりに換算して算出した。
(11) Water permeability performance A small module having an effective length of 20 cm consisting of four hollow fiber membranes was prepared, and distilled water was fed under conditions of a temperature of 25 ° C. and a filtration differential pressure of 16 kPa, and external pressure total filtration was performed for 30 minutes. The amount of permeated water (m 3 ) was determined. Next, it was calculated in terms of unit time (hr), unit membrane area (m 2 ), and 50 kPa.
＜実施例１＞
樹脂溶液Ａは重量平均分子量４１．７万のフッ化ビニリデンホモポリマー３８重量％を、γ-ブチロラクトン６２重量％に溶解して得た。樹脂溶液Ｂは極限粘度が３．１（ｄｌ／ｇ）のアクリルニトリル単独重合体を、ジメチルスルホキシドで希釈して重合体濃度が１１重量％を得た。樹脂溶液Ｃは重量平均分子量２８．４万のフッ化ビニリデンホモポリマーを１２重量％、セルロースアセテート（イーストマンケミカル社、ＣＡ４３５-７５Ｓ、三酢酸セルロース）５重量％、Ｎ-メチル-２-ピロリドン８３重量％を溶解して得た。
<Example 1>
Resin solution A was obtained by dissolving 38% by weight of vinylidene fluoride homopolymer having a weight average molecular weight of 417,000 in 62% by weight of γ-butyrolactone. In the resin solution B, an acrylonitrile homopolymer having an intrinsic viscosity of 3.1 (dl / g) was diluted with dimethyl sulfoxide to obtain a polymer concentration of 11% by weight. Resin solution C was 12% by weight of vinylidene fluoride homopolymer having a weight average molecular weight of 284,000, 5% by weight of cellulose acetate (Eastman Chemical Co., CA435-75S, cellulose triacetate), N-methyl-2-pyrrolidone 83 It was obtained by dissolving% by weight.
３重管状紡糸ノズルの内層スリットから樹脂溶液Ａを、外層スリットから樹脂溶液Ｂを、８５重量％のγ-ブチロラクトン水溶液を中心パイプから共に同心円状に押し出し、温度１０℃の水溶液中で固化させた後、１．５倍の延伸工程と脱溶媒工程を経て中空糸膜を得た。次にコーティングノズルを用いて、前記の中空糸膜に樹脂溶液Ｃを均一にコーティングし、温度３５℃の水溶液中で凝固させ、脱溶媒工程を経て複合中空糸膜を作製した。
得られた中空糸膜の膜壁構成は、支持層の平均厚さ２５６μｍ、中間層の平均厚さ５．４μｍ、外層の平均厚さ３４μｍ、最表面の平均細孔径が０．０７μｍであり、外径１３２２μｍ、内径７４０μｍであった。なお球状構造の平均粒径は１．８μｍ、三次元網目構造の平均細孔径は１．６μｍ、中間層の平均細孔径が０．０４μｍであり、透水性能が０．３８ｍ３／ｍ２・ｈｒであった。この複合中空糸膜でエアスクラビング耐久性評価を行い、評価後の中空糸膜で透水性能と阻止性能を測定した結果、透水性能が０．２８ｍ３／ｍ２・ｈｒ、阻止率が９９％で高い阻止性能を示した。なお評価結果を表１にまとめた。
The resin solution A was extruded from the inner layer slit of the triple tubular spinning nozzle, the resin solution B was extruded from the outer layer slit, and an 85% by weight γ-butyrolactone aqueous solution was extruded concentrically from the central pipe and solidified in an aqueous solution at a temperature of 10 ° C. Thereafter, a hollow fiber membrane was obtained through a 1.5-fold stretching step and a solvent removal step. Next, using a coating nozzle, the hollow fiber membrane was uniformly coated with the resin solution C and solidified in an aqueous solution at a temperature of 35 ° C., and a composite hollow fiber membrane was produced through a solvent removal step.
The membrane wall structure of the obtained hollow fiber membrane has an average thickness of the support layer of 256 μm, an average thickness of the intermediate layer of 5.4 μm, an average thickness of the outer layer of 34 μm, and an average pore diameter of the outermost surface of 0.07 μm. The outer diameter was 1322 μm and the inner diameter was 740 μm. The average particle diameter of the spherical structure is 1.8 μm, the average pore diameter of the three-dimensional network structure is 1.6 μm, the average pore diameter of the intermediate layer is 0.04 μm, and the water permeability is 0.38 m 3 / m 2 · hr. Met. Air scrubbing durability evaluation was performed with this composite hollow fiber membrane, and as a result of measuring the water permeability and blocking performance with the hollow fiber membrane after the evaluation, the water permeability was 0.28 m 3 / m 2 · hr, and the blocking rate was 99%. High blocking performance. The evaluation results are summarized in Table 1.
＜実施例２＞
実施例１と同様の樹脂溶液Ａ、樹脂溶液Ｂ、樹脂溶液Ｃを用いて、３重管状紡糸ノズルの内層スリットから樹脂溶液Ａを、外層スリットから樹脂溶液Ｃを、８５重量％のγ-ブチロラクトン水溶液を中心パイプから共に同心円状に押し出し、温度が１０℃の冷水中で固化させた後、１．５倍の延伸工程と脱溶媒工程を経て複合中空糸膜を作製した。次にコーティングノズルを用いて、前記複合中空糸膜に樹脂溶液Ｂを均一にコーティングし、２０重量％ジメチルスルホキシド水溶液中で凝固させ、脱溶媒工程を経て複合中空糸膜を作製した。得られた中空糸膜の膜壁構成は、支持層の平均厚さ２６４μｍ、中間層の平均厚さ４．４μｍ、外層の平均厚さ３７μｍ、最表面の平均細孔径が０．３１μｍであり、外径１３６０μｍ、内径７４９μｍであった。なお球状構造の平均粒径は１．９μｍ、三次元網目構造の平均細孔径は０．３μｍ、中間層の平均細孔径が０．０９μｍであり、透水性能が０．３７ｍ３／ｍ２・ｈｒであった。この複合中空糸膜でエアスクラビング耐久性評価を行い、評価後の中空糸膜で透水性能と阻止性能を測定した結果、透水性能が０．２７ｍ３／ｍ２・ｈｒ、阻止率が９９％、であった。なお評価結果を表１にまとめた。
<Example 2>
Using the same resin solution A, resin solution B, and resin solution C as in Example 1, the resin solution A from the inner layer slit of the triple tubular spinning nozzle, the resin solution C from the outer layer slit, and 85% by weight of γ-butyrolactone The aqueous solution was extruded concentrically from the center pipe and solidified in cold water having a temperature of 10 ° C., and then a composite hollow fiber membrane was produced through a 1.5-fold drawing process and a solvent removal process. Next, the resin solution B was uniformly coated on the composite hollow fiber membrane using a coating nozzle, and solidified in a 20% by weight dimethyl sulfoxide aqueous solution, and a composite hollow fiber membrane was produced through a desolvation step. The membrane wall structure of the obtained hollow fiber membrane has an average thickness of the support layer of 264 μm, an average thickness of the intermediate layer of 4.4 μm, an average thickness of the outer layer of 37 μm, and an average pore diameter of the outermost surface of 0.31 μm. The outer diameter was 1360 μm and the inner diameter was 749 μm. The average particle diameter of the spherical structure is 1.9 μm, the average pore diameter of the three-dimensional network structure is 0.3 μm, the average pore diameter of the intermediate layer is 0.09 μm, and the water permeability is 0.37 m 3 / m 2 · hr. Met. Air scrubbing durability evaluation was performed with this composite hollow fiber membrane, and as a result of measuring the water permeability and blocking performance with the hollow fiber membrane after the evaluation, the water permeability was 0.27 m 3 / m 2 · hr, the blocking rate was 99%, Met. The evaluation results are summarized in Table 1.
＜比較例１＞
実施例１の樹脂溶液Ａと樹脂溶液Ｃを用いて、３重管状紡糸ノズルの内層スリットから樹脂溶液Ａを、外層スリットから樹脂溶液Ｃを、８５重量％のγ-ブチロラクトン水溶液を中心パイプから共に同心円状に押し出し、温度が１０℃の水溶液中で固化させた後、１．５倍の延伸工程と脱溶媒工程を経て複合中空糸膜を作製した。得られた中空糸膜の膜壁構成は、支持層の平均厚さ２６０μｍ、外層の平均厚さ４２μｍ、最表面の平均細孔径が０．０８μｍであって、外径１３５４μｍ、内径７５０μｍであった。なお球状構造の平均粒径は１．９μｍ、三次元網目構造の平均細孔径は１．９μｍであった。純水透過性能が０．６８ｍ３／ｍ２・ｈｒであった。この複合中空糸膜でエアスクラビング耐久性評価を行い、評価後の中空糸膜で透水性能と阻止性能を測定した結果、透水性能が０．４８ｍ３／ｍ２・ｈｒ、阻止率が５４％であった。なお評価結果を表１にまとめた。
<Comparative Example 1>
Using the resin solution A and the resin solution C of Example 1, the resin solution A from the inner layer slit of the triple tubular spinning nozzle, the resin solution C from the outer layer slit, and the 85% by weight γ-butyrolactone aqueous solution together from the central pipe After extruding concentrically and solidifying in an aqueous solution having a temperature of 10 ° C., a composite hollow fiber membrane was produced through a 1.5-fold stretching step and a solvent removal step. The membrane structure of the obtained hollow fiber membrane was that the average thickness of the support layer was 260 μm, the average thickness of the outer layer was 42 μm, the average pore diameter of the outermost surface was 0.08 μm, the outer diameter was 1354 μm, and the inner diameter was 750 μm. . The average particle diameter of the spherical structure was 1.9 μm, and the average pore diameter of the three-dimensional network structure was 1.9 μm. The pure water permeation performance was 0.68 m 3 / m 2 · hr. This composite hollow fiber membrane was evaluated for air scrubbing durability, and as a result of measuring the water permeability and blocking performance with the hollow fiber membrane after the evaluation, the water permeability was 0.48 m 3 / m 2 · hr, and the blocking rate was 54%. there were. The evaluation results are summarized in Table 1.
＜比較例２＞
実施例１の樹脂溶液Ａと樹脂溶液Ｂを用いて、２重管状紡糸ノズルの外層スリットから樹脂溶液Ａを、８５重量％のγ-ブチロラクトン水溶液を中心パイプから共に同心円状に押し出し、温度が１０℃の８５重量％のγ-ブチロラクトン水溶液中で固化させた後、脱溶媒工程と１．５倍の延伸工程を経て中空糸支持膜を作製した。その後、前記中空糸支持膜に樹脂溶液Ｂを均一コーティングし、２０重量％ジメチルスルホキシド水溶液中で凝固させ、脱溶媒工程を経て複合中空糸膜を作製した。得られた中空糸膜の膜壁構成は、支持層の平均厚さ２６４μｍ、外層の平均厚さ４１μｍであり、外径１３７０μｍ、内径７６０μｍであった。なお球状構造の平均粒径は１．９μｍ、三次元網目構造の平均細孔径は０．３μｍ、最表面の平均細孔径が０．２３μｍであり、透水性能が０．４８ｍ３／ｍ２・ｈｒであった。この複合膜でエアスクラビング耐久性評価を行い、評価した後に容器から中空糸膜を取り出して、阻止性能と透水性能を測定した結果、阻止率が７８％、透水性能０．３５ｍ３／ｍ２・ｈｒであった。なお評価結果を表１にまとめた。
<Comparative example 2>
Using the resin solution A and the resin solution B of Example 1, the resin solution A was extruded from the outer slit of the double tubular spinning nozzle, and an 85% by weight γ-butyrolactone aqueous solution was extruded concentrically from the center pipe. After solidifying in an 85% by weight γ-butyrolactone aqueous solution at 0 ° C., a hollow fiber support membrane was produced through a solvent removal step and a 1.5-fold drawing step. Thereafter, the resin solution B was uniformly coated on the hollow fiber support membrane and coagulated in a 20% by weight dimethyl sulfoxide aqueous solution, and a composite hollow fiber membrane was produced through a solvent removal step. The hollow fiber membrane thus obtained had an average wall thickness of 264 μm, an average thickness of the outer layer of 41 μm, an outer diameter of 1370 μm, and an inner diameter of 760 μm. The average particle diameter of the spherical structure is 1.9 μm, the average pore diameter of the three-dimensional network structure is 0.3 μm, the average pore diameter of the outermost surface is 0.23 μm, and the water permeability is 0.48 m 3 / m 2 · hr. Met. Air scrubbing durability was evaluated with this composite membrane, and after evaluation, the hollow fiber membrane was taken out from the container and measured for blocking performance and water permeability. As a result, the blocking rate was 78% and the water permeability 0.35 m 3 / m 2. hr. The evaluation results are summarized in Table 1.
＜実施例３＞
実施例１と同様の樹脂溶液Ａ、樹脂溶液Ｂ、樹脂溶液Ｃを用いて、４重管状紡糸ノズルの内層スリットから樹脂溶液Ａを、中間スリットから樹脂溶液Ｂ、外層スリットから樹脂溶液Ｃを、８５重量％のγ-ブチロラクトン水溶液を中心パイプから共に同心円状に押し出し、温度が１０℃の水溶液中で固化させた後、脱溶媒工程と１．３倍の延伸工程を経て複合中空糸膜を作製した。得られた中空糸膜の膜壁構成は、支持層の平均厚さ２６８μｍ、中間層の平均厚さ４．４μｍ、外層の平均厚さ４０μｍ、最表面の平均細孔径が０．０２μｍであり、外径１３７９μｍ、内径７５４μｍであった。なお球状構造の平均粒径は１．８μｍ、三次元網目構造の平均細孔径は２．１μｍ、中間層の平均細孔径が０．０５μｍであり、透水性能が０．５４ｍ３／ｍ２・ｈｒであった。この複合膜でエアスクラビング耐久性評価を行い、評価した後に容器から中空糸膜を取り出して阻止性能と透水性能を測定した結果、阻止率が９９％、透水性能０．４１ｍ３／ｍ２・ｈｒであった。なお評価結果を表１にまとめた。
<Example 3>
Using the same resin solution A, resin solution B, and resin solution C as in Example 1, resin solution A from the inner layer slit of the quadruple tubular spinning nozzle, resin solution B from the intermediate slit, and resin solution C from the outer layer slit, A 85% by weight γ-butyrolactone aqueous solution is extruded concentrically from the center pipe, solidified in an aqueous solution at a temperature of 10 ° C, and then a composite hollow fiber membrane is produced through a solvent removal step and a 1.3 times stretching step. did. The membrane wall structure of the obtained hollow fiber membrane has an average thickness of 268 μm of the support layer, an average thickness of 4.4 μm of the intermediate layer, an average thickness of 40 μm of the outer layer, and an average pore diameter of the outermost surface of 0.02 μm. The outer diameter was 1379 μm and the inner diameter was 754 μm. The average particle diameter of the spherical structure is 1.8 μm, the average pore diameter of the three-dimensional network structure is 2.1 μm, the average pore diameter of the intermediate layer is 0.05 μm, and the water permeability is 0.54 m 3 / m 2 · hr. Met. After evaluating the air scrubbing durability with this composite membrane and taking out the hollow fiber membrane from the container and measuring the blocking performance and water permeability, the blocking rate was 99% and the water permeability 0.41 m 3 / m 2 · hr. Met. The evaluation results are summarized in Table 1.
本発明によれば中空糸膜の分離機能を複層化しているために、従来のエアスクラビング運転での膜擦過による分離機能の低下を抑制し、透過水の水質が安定する。これにより膜の長期再生使用が可能になる。 According to the present invention, since the separation function of the hollow fiber membrane is multi-layered, the deterioration of the separation function due to membrane rubbing in the conventional air scrubbing operation is suppressed, and the quality of the permeated water is stabilized. This makes it possible to use the membrane for a long time.
Claims (2)
三次元網目構造の外層の平均細孔径が０．１μｍ以上１０μｍ以下であり、緻密な中間層の平均細孔径が０．１μｍ未満であり、球状構造を構成する球状の固形分の平均直径が０．１μｍ以上５μｍ以下であり、
三次元網目構造の外層と緻密な中間層が、非溶媒誘起相分離により形成された構造であり、
球状構造の支持層が熱誘起相分離により形成された構造であり、
（１）外層スリット、内層スリットおよび中心パイプを備える紡糸ノズルを用いて、前記内層スリットから前記球状構造を形成する樹脂溶液Ａを、外層スリットから中間層を形成する樹脂溶液Ｂを、中心パイプから内部凝固液を、共に押し出し、外部凝固液で冷却して凝固させる工程と、溶媒を抜く工程とを経て複合中空糸膜状物を得て、さらに該複合中空糸膜状物にコーティングノズルを用いて三次元網目構造を形成する樹脂溶液Ｃを塗布し、前記樹脂溶液Ｃを凝固させる工程を経る方法；または
（２）外層スリット、中間スリット、内層スリットおよび中心パイプを備える紡糸ノズルを用いて、前記内層スリットから球状構造を形成する樹脂溶液Ａを、中間スリットから中間層を形成する樹脂溶液Ｂを、外層ノズルから三次元網目構造を形成する樹脂溶液Ｃを、中心パイプから内部凝固液を、共に押し出し、外部凝固液で冷却して凝固させる工程と、溶媒を抜く工程とを経る方法のいずれかの方法により製造されることを特徴とする複合中空糸膜。 A composite hollow fiber membrane formed by an outer layer of a three-dimensional network structure, a dense intermediate layer that follows, and a support layer of a spherical structure that supports it,
The average pore diameter of the outer layer of the three-dimensional network structure is 0.1 μm or more and 10 μm or less, the average pore diameter of the dense intermediate layer is less than 0.1 μm, and the average diameter of the spherical solid component constituting the spherical structure is 0 der more than 5μm or less .1μm is,
The outer layer of the three-dimensional network structure and the dense intermediate layer are formed by non-solvent induced phase separation,
A spherical structure support layer is formed by thermally induced phase separation,
(1) Using a spinning nozzle having an outer layer slit, an inner layer slit, and a center pipe, a resin solution A that forms the spherical structure from the inner layer slit, and a resin solution B that forms an intermediate layer from the outer layer slit from the center pipe A composite hollow fiber membrane is obtained through a process of extruding the internal coagulation liquid together, cooling with an external coagulation liquid and solidifying, and a process of removing the solvent, and a coating nozzle is used for the composite hollow fiber membrane. Applying a resin solution C forming a three-dimensional network structure and solidifying the resin solution C; or
(2) Using a spinning nozzle having an outer layer slit, an intermediate slit, an inner layer slit and a center pipe, the resin solution A that forms a spherical structure from the inner layer slit, and the resin solution B that forms an intermediate layer from the intermediate slit Either of the method of passing through the step of extruding the resin solution C forming a three-dimensional network structure from the nozzle together with the internal coagulating liquid from the center pipe and cooling with the external coagulating liquid, and the step of removing the solvent A composite hollow fiber membrane manufactured by the method described above.
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| JP2008089926A JP5292890B2 (en) | 2008-03-31 | 2008-03-31 | Composite hollow fiber membrane |
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| JP2008089926A JP5292890B2 (en) | 2008-03-31 | 2008-03-31 | Composite hollow fiber membrane |
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| JP2009240899A JP2009240899A (en) | 2009-10-22 |
| JP2009240899A5 JP2009240899A5 (en) | 2011-05-12 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104043343A (en) * | 2014-05-05 | 2014-09-17 | 杭州求是膜技术有限公司 | Hollow fiber membrane plug processing technology |
| JP7321978B2 (en) | 2015-10-28 | 2023-08-07 | インターコンチネンタル グレート ブランズ エルエルシー | Method for preparing encapsulated compositions for use in edible compositions |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5549955B2 (en) * | 2011-04-20 | 2014-07-16 | 三菱レイヨン株式会社 | Porous membrane manufacturing method and manufacturing apparatus |
| KR101445958B1 (en) * | 2013-01-24 | 2014-10-01 | 주식회사 효성 | Method for preparing hollow fiber membrane using four hole nozzle |
| KR101443491B1 (en) | 2013-01-24 | 2014-09-24 | 주식회사 효성 | Method for preparing hollow fiber membrane and hollow fiber membrane prepared thereby |
| CN105636676B (en) | 2013-10-11 | 2018-05-22 | 三菱化学株式会社 | Hollow porous membranes |
| KR101619403B1 (en) * | 2014-08-04 | 2016-05-10 | 롯데케미칼 주식회사 | Preparation method of hollow fiber membrane and hollow fiber membrane |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11253768A (en) * | 1998-03-13 | 1999-09-21 | Mitsubishi Rayon Co Ltd | Composite hollow fiber membrane and manufacture thereof |
| ES2374814T3 (en) * | 2002-06-14 | 2012-02-22 | Toray Industries, Inc. | POROUS MEMBRANE AND MANUFACTURING PROCEDURE OF A POROUS MEMBRANE. |
| JP5078050B2 (en) * | 2003-03-31 | 2012-11-21 | 東レ株式会社 | Coating nozzle for hollow fiber membrane and method for producing composite hollow fiber membrane using the same |
| JP5066810B2 (en) * | 2005-02-04 | 2012-11-07 | 東レ株式会社 | Polymer separation membrane and production method thereof |
| CA2655907A1 (en) * | 2006-06-27 | 2008-01-03 | Toray Industries, Inc. | Polymer separation membrane and process for producing the same |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104043343A (en) * | 2014-05-05 | 2014-09-17 | 杭州求是膜技术有限公司 | Hollow fiber membrane plug processing technology |
| CN104043343B (en) * | 2014-05-05 | 2016-05-18 | 杭州求是膜技术有限公司 | A kind of hollow-fibre membrane plug processing technology |
| JP7321978B2 (en) | 2015-10-28 | 2023-08-07 | インターコンチネンタル グレート ブランズ エルエルシー | Method for preparing encapsulated compositions for use in edible compositions |
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| JP2009240899A (en) | 2009-10-22 |
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