JP2004025066A - Method for manufacturing porous hollow fiber membrane - Google Patents
Method for manufacturing porous hollow fiber membrane Download PDFInfo
- Publication number
- JP2004025066A JP2004025066A JP2002186636A JP2002186636A JP2004025066A JP 2004025066 A JP2004025066 A JP 2004025066A JP 2002186636 A JP2002186636 A JP 2002186636A JP 2002186636 A JP2002186636 A JP 2002186636A JP 2004025066 A JP2004025066 A JP 2004025066A
- Authority
- JP
- Japan
- Prior art keywords
- hollow fiber
- fiber membrane
- atmosphere
- porous hollow
- film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、多孔質中空糸膜の製造方法に関し、更に詳しくは、高透過係数をもち且つ欠陥点が少なく安定した紡糸が可能な多孔質中空糸膜の製造方法に関する。
【０００２】
【従来の技術とその課題】
各種の膜形成性樹脂溶液を乾湿式紡糸して多孔質中空糸膜を製造する場合、ノズル吐出口から凝固浴表面までを空走させる区間の温度・湿度条件などによって、多孔質中空糸膜の外表面側に形成される多孔質部の孔径が大きく左右される。一般的に非溶媒誘起型相分離法によりスピノーダル分解をさせた製膜法では、空走部における水蒸気の吸収量が多くなるに連れて製造される膜の孔径及び透過係数が大きくなる傾向にある。
【０００３】
特にこのような傾向は、膜形成性樹脂としてポリスルホン系樹脂、ポリフッ化ビニリデン系樹脂、ポリアクリロニトリル系樹脂等を用いた場合に顕著である。
【０００４】
例えば、特開昭６３−１３９９３０号公報には、平板上に流延した製膜原液の表面に相対湿度を、４０〜５０％に調節した空気に数秒から数十秒接触させたのち、凝固浴に浸漬させる方法が開示されている。この方法によって、膜表層の孔径を制御し、透過流量を向上させることが可能となるが、気相部での接触時間が長く、紡糸安定性の観点から中空糸膜の製造に適した方法とは言い難く、その接触時間が短い場合には十分な効果が得られないという問題があった。
【０００５】
また、特開平７−１６３８４９号公報及び特開平９−２９０７８号公報等には、空走部の相対湿度を８０〜１００％、温度を４０〜５０℃と高くすることにより、比較的短い距離で十分な吸湿をさせる方法が開示されているが、吐出温度（ノズル表面温度） 条件によってはノズル表面が結露し、紡糸安定性を損なうという問題があった。
【０００６】
これに対し、特開２００２−５８９７１号公報では、乾湿式紡糸法における空走部にノズル吐出口付近の低湿度雰囲気部とそれ以外の高湿度雰囲気部との２領域を設けることにより、ノズル下面への水滴の付着を防止し、安定した紡糸を可能とする方法が開示されている。
【０００７】
しかしながら、上記方法では、凝固浴温度が紡糸雰囲気温度より高く、ノズル付近の雰囲気温度が紡糸雰囲気温度以下である場合、両領域の界面近傍で水蒸気が凝縮して水滴（湯気） を生成することがあった。これが空走中の紡糸原液表面に付着すると、局所的な凝固の斑、水吸収斑となり、膜品質の低下を招くという問題があった。
【０００８】
本発明はこれらの従来の問題を解決し、高い透過性能のみならず、膜品質及び紡糸安定性に優れた多孔質膜の製造方法を提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明者らは、上記目的を達成するため多方面からの検討を重ねた結果、乾湿式紡糸における空走部の湿度及び温度を制御することにより高い透過性能を維持したまま、膜品質及び紡糸安定性に優れた多孔質膜の製造方法を得るに至った。
【００１０】
すなわち、本発明の基本的な構成は、膜形成性樹脂溶液を乾湿式紡糸して中空糸膜を製造する際に、ノズル吐出口から凝固浴表面までの空走部雰囲気中の絶対湿度と空走時間との積が、０．０４ｋｇ／ｍ３ ・ｓ以上であることを特徴とする多孔質中空糸膜の製造方法にある。
【００１１】
本発明における重要な要件は、
（１） 高い透過性能を発現するために、空走部において十分に水蒸気を吸収し、表層近傍でのスピノーダル分解を促進することによって孔径と高い空隙率を確保すること、
（２） 紡糸安定性を維持するために、ノズル表面における結露、水滴の付着を防止することにより、糸切れ等の発生を防止すること、
（３） 高い膜品質を得るために、空走部における水蒸気の凝縮、水滴（湯気） の発生を抑えることにより、局所的な凝固の斑、水吸収量の斑を防止すること、
である。
【００１２】
また、十分な水蒸気の吸収は、高い透過性能を確保するのみでなく、分離活性機能を有する緻密層が中空糸膜外表面から膜内部に移動することにより、製膜（後） 工程、及び膜使用時の外的要因対する品質低下の抑制にも効果がある。
【００１３】
なお、本発明にいう高い膜品質とは、空走部における吸湿及び凝固液中での凝固作用による正常な相分離に基づいて得られる孔径分布には明らかに属し得ない大きな孔（欠陥点） を有する頻度が低い、又は有さないものをいう。
これらの総ての要件を満たすことにより本件発明の上記目的が達成される。
【００１４】
【発明の実施の形態】
以下、本発明の好適な実施の形態について詳細に説明する。
本発明において使われる膜形成性樹脂は、乾湿式紡糸により多孔質中空糸膜を形成し得るものであれば特に限定されるものではないが、ポリスルホンやポリエーテルスルホンなどのポリスルホン系樹脂、ポリアクリロニトリル、セルロース誘導体、ポリフッ化ビニリデンなどのフッ素系樹脂、ポリアミド、ポリエステル、ポリメタクリレート、ポリアクリレートなどが挙げられる。また、これらの樹脂の共重合体や一部に置換基を導入したものであっても良い。さらに、２種以上の樹脂を混合したものであっても良い。
【００１５】
本発明において使われる膜形成性樹脂の溶媒は、膜形成性樹脂を溶解し得るものであれば特に限定されるものではないが、乾湿式紡糸の空走部において膜形成性樹脂溶液に吸湿させることから、水と均一に混合可能なものが好ましく、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、ジメチルスルホキシド、Ｎ−メチル−２− ピロリドン、Ｎ−メチルモルホリン−Ｎ− オキシドなどが挙げられる。
【００１６】
本発明における膜形成性樹脂溶液は、１０〜３０質量％、好ましくは１５〜２５質量％の膜形成性樹脂を均一に上述の溶媒に溶解させて得られる。このとき、相分離を制御するための添加剤として、ポリビニルピロリドン、ポリエチレングリコール、ポリビニルアセテート、ポリビニルアルコールなどの親水性高分子や、水、アルコールなどの非溶媒、無機塩などを添加してもよい。添加剤を使用する場合、その濃度は１〜２０質量％が好ましく、５〜１２質量％がより好ましい。
【００１７】
本発明による多孔質中空糸膜は、膜形成性樹脂溶液を二重環状ノズルから押し出し、一定距離を空走させた後、水性凝固浴中に浸漬して凝固させることにより形成させることができる。このとき、必要に応じ二重環状ノズルの芯部から水等の凝固液や、丸打ちの組み紐など多孔質な支持体を同時に押し出してもよく、環状吐出部から繊維等の補強体を同時に吐出してもよい。
【００１８】
本発明において、ノズルより吐出された膜形成性樹脂溶液が凝固液に浸漬されるまでに、乾湿式紡糸空走部雰囲気を下式（１） を満たす条件とする。
（空走部雰囲気の絶対湿度［ｋｇ／ｍ３］）×（空走時間［ｓ］）≧０．０４［ｋｇ／ｍ３・ｓ］…（１）
更に好ましくは、式（１） の右辺が０．０８［ｋｇ／ｍ３ ・ ｓ］ である。
【００１９】
空走部雰囲気の絶対湿度と空走時間の積が０．０４ ｋｇ／ｍ３・ｓ未満になると、空走部において十分な吸湿量が得られず、透過性能・膜品質における十分な効果が得られにくい。
なお、空走部の温度や湿度は、全体で均一とする必要はなく、多段階に制御しても構わない。その場合、本発明における空走部雰囲気に関する前述の式（１） は、各々の空走部における絶対湿度と空走時間の積の和を用いる。即ち、例えば絶対湿度Ａ［ｋｇ／ｍ３］ 、空走時間ａ［ｓ］ の空走部と、絶対湿度Ｂ［ｋｇ／ｍ３］ 、空走時間ｂ［ｓ］ の空走部とを有する場合、前述の絶対湿度と空走時間の積は、Ａ×ａ＋Ｂ×ｂで求められる。
【００２０】
空走部の温度や湿度を多段階に制御する場合、隣接する各段の境界部で水蒸気が凝結することを防止するため、隣接する空走部雰囲気の露点同士が、互いに高くなるように制御することが好ましい。例えば、一つの空走部雰囲気が、温度６０℃、露点６０℃である場合、これと隣接する空走部雰囲気は、温度６５℃、露点５５℃とすれば、いずれの空走部雰囲気温度も、隣接する空走部雰囲気の露点よりも高くなるため、境界部で水蒸気が凝結することはない。
【００２１】
本発明におけるノズル表面温度は、乾湿式紡糸の空走部雰囲気の露点以上とすることが好ましい。ノズル表面温度が空走部雰囲気の露点未満であるとノズル表面が結露し紡糸安定性を損なう。
なお、空走部が多段の場合のように雰囲気が均一でない場合、ノズル表面温度は、ノズル近傍の空走部雰囲気の露点以上となるようにすることが好ましい。
【００２２】
本発明における凝固液温度は、乾湿式紡糸の空走部雰囲気の露点以上であることが好ましい。凝固液温度が空走部雰囲気の露点未満になると、空走部雰囲気が凝固液表面で冷却され、凝固液との界面付近で水蒸気が凝縮し、これが空走する膜形成性樹脂溶液と接触することにより凝固斑が起こり、膜品質を低下させる原因となる。
なお、空走部が多段の場合のように雰囲気が均一でない場合、凝固液温度は、凝固液近傍の空走部雰囲気の露点以上となるようにすることが好ましい。
【００２３】
本発明における膜形成性樹脂溶液の吐出温度は、乾湿式紡糸空走部雰囲気の露点以上であることが好ましい。露点以上とすることにより、膜形成性樹脂溶液表面に、気体状の水（水蒸気）が均一かつ速やかに吸収される。膜形成性樹脂溶液の吐出温度が空走部雰囲気の露点未満であると、空走部において膜形成性樹脂溶液表面が結露しやすく、膜の品質を低下させることがある。
なお、空走部が多段の場合のように雰囲気が均一でない場合、吐出温度は、吐出部近傍の空走部雰囲気の露点以上となるようにする。
【００２４】
本発明における乾湿式紡糸空走部雰囲気の相対湿度は、６０％以上１００％以下であることが好ましい。更に好ましくは８０％以上１００％以下である。相対湿度が６０％よりも低くなると、十分な吸湿量を得るために空走部距離を長くせざるを得ず、紡糸安定性を低下させる恐れが生じる。
【００２５】
また、空走部距離をより短くするためには、空走部雰囲気の温度を高くし、飽和水蒸気量を高めることが有効である。したがって、乾湿式紡糸の空走部雰囲気の温度は、４０℃以上１００℃以下であることが有効である。更に好ましくは６０℃以上８０℃以下である。１００℃よりも高くなると、水性凝固液を空走部雰囲気の露点以上に維持することが困難となり好ましくない。
【００２６】
空走部雰囲気はどのような方法・装置を用いてもよいが、例えば、空走部に膜形成性樹脂溶液の入口と出口用の孔を設けた以外は密閉した容器とし、そこへ調湿調温された空気を送入することや、凝固液面上に膜形成性樹脂溶液の入口用の孔を設けた保温可能なお椀状の容器を被せ、必要であればそこに調湿空気を導入することにより達成できる。
【００２７】
次に、本発明の繊維強化多孔質膜について好適な実施例を挙げて具体的に説明する。なお、本発明は以下の実施例に限定されるものではないことは勿論である。
【００２８】
（実施例１）
ポリフッ化ビニリデン（カイナー３０１Ｆ；アトケム製） ２０質量部、ポリビニルピロリドン（Ｋ−１２０；ＩＳＰ 製） １０質量部をＮ，Ｎ−ジメチルアセトアミド８０質量部に６０℃で４時間加熱攪拌溶解し、均一な溶液を得た。この溶液を、外径１．５ｍｍ、内径０．７ｍｍからなる７０℃に保温された（溶液の吐出温度：７０℃） 二重環状ノズルの環状部から吐出すると共に、Ｎ，Ｎ−ジメチルアセトアミド３０質量部、グリセリン４０質量部、水３０質量部からなる内部凝固液を同ノズルの芯部から吐出し、４ｃｍの空走部（空走時間０．６０ｓ）を経た後、７０℃に保温されたＮ，Ｎ−ジメチルアセトアミド５質量部、水９５質量部からなる凝固液に導き４ｍ／ｍｉｎの速度で枷に巻き取り中空糸膜を得た。
【００２９】
このとき、空走部は容器で密閉し、温度は６８℃、相対湿度は１００％（空走部露点：６８℃）、絶対湿度０．１８２ｋｇ／ｍ３ となるように調節した。空走部雰囲気の絶対湿度［ｋｇ／ｍ３］ と空走時間［ｓ］ との積は、０．１０９２であった。この状態で２４時間の連続紡糸を実施したところ、ノズル下面での水蒸気の凝縮は認められず、安定した連続紡糸が可能であった。
【００３０】
得られた中空糸膜を４０℃、１０００ｍｇ／Ｌの次亜塩素酸ナトリウム水溶液に１２時間浸漬、次いで６０℃の水に１時間浸漬して洗浄した後、６０℃で３時間乾燥した。
得られた中空糸膜の外径は１．２ｍｍ、内径は０．８ｍｍであり、透過性能を示す純水透過係数は１８０（ｍ３ ／ｍ２ ／ｈｒ／ＭＰａ）であった。また、測定媒体として９９．５％エタノールを用い、ＡＳＴＭ Ｆ３１６−８６の方法に基づいて測定した最大孔径圧力は１４０ｋＰａ（換算孔径約０．４５μｍ）、平均孔径圧力は１９０ｋＰａ（換算孔径約０．３５μｍ）であった。この膜の外表面を電子顕微鏡（ＳＥＭ）で観察したところ、約２μｍの網目状の孔が認められ、分離活性層が膜表面より内部に移動していることが確認できた。
【００３１】
更に、バブルポイント法（測定媒体：９９．５％エタノール） により、中空糸膜１０ｍ中の品質検査（欠陥点数測定） を実施したところ、８０ｋＰａ以下（換算孔径約０．８μｍ以上） の孔は計測されなかった。
【００３２】
以上のとおり、本発明によれば高い透過性能を発現し、かつ紡糸安定性及び膜品質の優れた多孔質中空糸膜を容易に得ることが可能となったことが理解できよう。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a porous hollow fiber membrane, and more particularly, to a method for producing a porous hollow fiber membrane having a high permeability coefficient and capable of performing stable spinning with few defect points.
[0002]
[Prior art and its problems]
When a porous hollow fiber membrane is manufactured by dry-wet spinning of various film-forming resin solutions, the porous hollow fiber membrane is produced depending on the temperature and humidity conditions in the section where the nozzle runs from the nozzle outlet to the surface of the coagulation bath. The pore diameter of the porous portion formed on the outer surface side is greatly affected. In general, in a film forming method in which spinodal decomposition is performed by a non-solvent-induced phase separation method, the pore size and the permeability coefficient of the manufactured film tend to increase as the amount of water vapor absorbed in the free running portion increases. .
[0003]
In particular, such a tendency is remarkable when a polysulfone resin, a polyvinylidene fluoride resin, a polyacrylonitrile resin, or the like is used as the film-forming resin.
[0004]
For example, JP-A-63-139930 discloses that a surface of a film forming stock solution cast on a flat plate is brought into contact with air having a relative humidity adjusted to 40 to 50% for several seconds to several tens of seconds, followed by coagulation bath. A method for immersion in a varnish is disclosed. By this method, it is possible to control the pore diameter of the membrane surface layer and improve the permeation flow rate, but the contact time in the gas phase is long, and a method suitable for producing a hollow fiber membrane from the viewpoint of spinning stability. However, if the contact time is short, there is a problem that a sufficient effect cannot be obtained.
[0005]
Further, JP-A-7-163849 and JP-A-9-29078 disclose that the relative humidity of the free running portion is increased to 80% to 100% and the temperature is increased to 40 ° C to 50 ° C so that a relatively short distance can be obtained. Although a method for sufficiently absorbing moisture has been disclosed, there has been a problem that, depending on the conditions of the discharge temperature (nozzle surface temperature), dew condensation occurs on the nozzle surface, and spinning stability is impaired.
[0006]
On the other hand, in Japanese Patent Application Laid-Open No. 2002-58971, in the dry-wet spinning method, two regions of a low-humidity atmosphere portion near the nozzle discharge port and a high-humidity atmosphere portion other than that are provided in the idle running portion, so that the lower surface of the nozzle is provided. There is disclosed a method of preventing water droplets from adhering to the surface and enabling stable spinning.
[0007]
However, in the above method, when the coagulation bath temperature is higher than the spinning ambient temperature and the ambient temperature near the nozzle is lower than or equal to the spinning ambient temperature, water vapor condenses near the interface between the two regions to generate water droplets (steam). there were. If this adheres to the surface of the spinning stock solution during idle running, there is a problem that local coagulation spots and water absorption spots are caused, leading to a decrease in film quality.
[0008]
An object of the present invention is to solve these conventional problems and to provide a method for producing a porous membrane having not only high permeation performance but also excellent membrane quality and spinning stability.
[0009]
[Means for Solving the Problems]
The present inventors have conducted various studies in order to achieve the above object, and as a result, the film quality and spinning were maintained while maintaining high permeation performance by controlling the humidity and temperature of the free running section in dry-wet spinning. A method for producing a porous film having excellent stability has been obtained.
[0010]
In other words, the basic configuration of the present invention is that when a hollow fiber membrane is manufactured by spin-drying a film-forming resin solution to produce a hollow fiber membrane, the absolute humidity and air in the air running section atmosphere from the nozzle orifice to the surface of the coagulation bath are adjusted. A method for producing a porous hollow fiber membrane, wherein a product of the running time and the product is 0.04 kg / m 3 · s or more.
[0011]
Important requirements in the present invention are:
(1) In order to achieve high permeation performance, ensure sufficient pore size and high porosity by sufficiently absorbing water vapor in the free running section and promoting spinodal decomposition near the surface layer;
(2) In order to maintain spinning stability, prevent dew condensation and water droplets from adhering to the nozzle surface to prevent yarn breakage and the like;
(3) In order to obtain high film quality, by suppressing the condensation of water vapor and the generation of water droplets (steam) in the free running section, it is possible to prevent spots of local coagulation and spots of water absorption,
It is.
[0012]
In addition, sufficient absorption of water vapor not only ensures high permeation performance, but also allows the dense layer having a separation activity to move from the outer surface of the hollow fiber membrane to the inside of the membrane, thereby forming a membrane (post) process and a membrane. It is also effective in suppressing quality deterioration due to external factors during use.
[0013]
The high film quality referred to in the present invention means large pores (defect points) that cannot clearly belong to the pore size distribution obtained based on normal phase separation due to moisture absorption in the free running portion and coagulation in the coagulation liquid. Is low or has no frequency.
The above object of the present invention is achieved by satisfying all these requirements.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail.
The membrane-forming resin used in the present invention is not particularly limited as long as it can form a porous hollow fiber membrane by dry-wet spinning, but polysulfone-based resins such as polysulfone and polyethersulfone, and polyacrylonitrile , A cellulose derivative, a fluorine-based resin such as polyvinylidene fluoride, polyamide, polyester, polymethacrylate, polyacrylate and the like. Further, copolymers of these resins or those obtained by introducing a substituent into a part thereof may be used. Further, a mixture of two or more resins may be used.
[0015]
The solvent of the film-forming resin used in the present invention is not particularly limited as long as it can dissolve the film-forming resin, but the film-forming resin solution absorbs moisture in the free running section of the dry-wet spinning. Therefore, those which can be uniformly mixed with water are preferable, and examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, and N-methylmorpholine-N-oxide. Can be
[0016]
The film-forming resin solution in the present invention is obtained by uniformly dissolving 10 to 30% by mass, preferably 15 to 25% by mass of the film-forming resin in the above-mentioned solvent. At this time, as an additive for controlling phase separation, a hydrophilic polymer such as polyvinylpyrrolidone, polyethylene glycol, polyvinyl acetate, and polyvinyl alcohol, a non-solvent such as water and alcohol, and an inorganic salt may be added. . When an additive is used, its concentration is preferably from 1 to 20% by mass, more preferably from 5 to 12% by mass.
[0017]
The porous hollow fiber membrane according to the present invention can be formed by extruding a membrane-forming resin solution from a double annular nozzle, allowing it to run for a certain distance, and then immersing it in an aqueous coagulation bath for coagulation. At this time, if necessary, a coagulating liquid such as water or a porous support such as a round braid may be simultaneously extruded from the core portion of the double annular nozzle, and a reinforcing body such as a fiber is simultaneously ejected from the annular ejection portion. May be.
[0018]
In the present invention, the dry-wet spinning free-running section atmosphere is set to satisfy the following expression (1) before the film-forming resin solution discharged from the nozzle is immersed in the coagulation liquid.
(Absolute humidity [kg / m 3 ] of idle running section atmosphere) × (idling time [s]) ≧ 0.04 [kg / m 3 · s] (1)
More preferably, the right side of the equation (1) is 0.08 [kg / m 3 · s].
[0019]
If the product of the absolute humidity of the atmosphere of the free running section and the free running time is less than 0.04 kg / m 3 · s, a sufficient amount of moisture absorption cannot be obtained in the free running section, and a sufficient effect on permeation performance and membrane quality is not obtained. It is difficult to obtain.
Note that the temperature and humidity of the idle running section need not be uniform throughout, and may be controlled in multiple stages. In this case, the above-mentioned equation (1) relating to the atmosphere of the free running section in the present invention uses the sum of the product of the absolute humidity and the free running time in each free running section. That is, for example, it has an idle section having an absolute humidity of A [kg / m 3 ] and an idle time a [s] and an idle section having an absolute humidity of B [kg / m 3 ] and an idle time b [s]. In this case, the product of the above-mentioned absolute humidity and idle running time is obtained by A × a + B × b.
[0020]
When controlling the temperature and humidity of the free running section in multiple stages, control the dew points of the adjacent free running sections so that the dew points of the adjacent free running sections become higher to prevent condensation of water vapor at the boundary between adjacent steps. Is preferred. For example, if one atmosphere of the free running section has a temperature of 60 ° C. and a dew point of 60 ° C., the free running section atmosphere adjacent thereto has a temperature of 65 ° C. and a dew point of 55 ° C. Since the dew point is higher than the dew point of the atmosphere in the adjacent free running section, water vapor does not condense at the boundary.
[0021]
The nozzle surface temperature in the present invention is preferably equal to or higher than the dew point of the dry running section spinning atmosphere. If the nozzle surface temperature is lower than the dew point of the idling portion atmosphere, the nozzle surface is condensed and spinning stability is impaired.
In addition, when the atmosphere is not uniform as in the case of a multi-stage free running section, it is preferable that the nozzle surface temperature be equal to or higher than the dew point of the free running section atmosphere near the nozzle.
[0022]
The temperature of the coagulating liquid in the present invention is preferably equal to or higher than the dew point of the dry running section spinning atmosphere. When the temperature of the coagulating liquid is lower than the dew point of the free running part atmosphere, the free running part atmosphere is cooled on the surface of the coagulating liquid, and water vapor condenses near the interface with the coagulating liquid, which comes into contact with the free running film forming resin solution. As a result, coagulation spots occur and cause deterioration of membrane quality.
In addition, when the atmosphere is not uniform as in the case where the free running section has multiple stages, it is preferable that the coagulation liquid temperature be equal to or higher than the dew point of the free running section atmosphere near the coagulation liquid.
[0023]
The discharge temperature of the film-forming resin solution in the present invention is preferably equal to or higher than the dew point of the dry-wet spinning idle running section atmosphere. By setting the dew point or higher, gaseous water (water vapor) is uniformly and quickly absorbed on the surface of the film-forming resin solution. If the discharge temperature of the film-forming resin solution is lower than the dew point of the atmosphere of the free running section, the surface of the film-forming resin solution easily forms dew in the free running section, which may degrade the quality of the film.
In the case where the atmosphere is not uniform as in the case of a multi-stage free running section, the discharge temperature is set to be equal to or higher than the dew point of the free running section atmosphere near the discharge section.
[0024]
The relative humidity of the dry-wet spinning idle running atmosphere in the present invention is preferably 60% or more and 100% or less. More preferably, it is 80% or more and 100% or less. If the relative humidity is lower than 60%, the idle running distance must be increased in order to obtain a sufficient moisture absorption, and there is a fear that spinning stability may be reduced.
[0025]
Further, in order to shorten the distance of the free running section, it is effective to increase the temperature of the atmosphere of the free running section and increase the amount of saturated steam. Therefore, it is effective that the temperature of the free running section atmosphere of the dry-wet spinning is 40 ° C. or more and 100 ° C. or less. More preferably, it is 60 ° C. or more and 80 ° C. or less. If the temperature is higher than 100 ° C., it is difficult to maintain the aqueous coagulation liquid at the dew point of the free running section atmosphere or higher, which is not preferable.
[0026]
Although any method and apparatus may be used for the atmosphere of the free running section, for example, a closed container is provided except that the free running section is provided with an inlet and an outlet for the film-forming resin solution, and the humidity is adjusted there. To feed the conditioned air or cover the coagulating liquid surface with a heat-retainable bowl-shaped container with a hole for the entrance of the film-forming resin solution, and if necessary, humidify the air there. This can be achieved by introduction.
[0027]
Next, the fiber-reinforced porous membrane of the present invention will be specifically described with reference to preferred examples. The present invention is, of course, not limited to the following embodiments.
[0028]
(Example 1)
20 parts by mass of polyvinylidene fluoride (Kyner 301F; manufactured by Atochem) and 10 parts by mass of polyvinylpyrrolidone (K-120; manufactured by ISP) are dissolved in N, N-dimethylacetamide (80 parts by mass) under heating at 60 ° C. for 4 hours while stirring and dissolving. A solution was obtained. This solution was kept at 70 ° C. having an outer diameter of 1.5 mm and an inner diameter of 0.7 mm (discharge temperature of the solution: 70 ° C.). The solution was discharged from the annular portion of the double annular nozzle, and N, N-dimethylacetamide 30 was discharged. An internal coagulation liquid consisting of parts by mass, 40 parts by mass of glycerin, and 30 parts by mass of water was discharged from the core of the nozzle, and after passing through a 4 cm idling portion (idling time: 0.60 s), the temperature was kept at 70 ° C. The mixture was led to a coagulation liquid consisting of 5 parts by mass of N, N-dimethylacetamide and 95 parts by mass of water, and wound at a speed of 4 m / min and wound to obtain a hollow fiber membrane.
[0029]
At this time, the free running section was sealed with a container, and the temperature and the relative humidity were adjusted to be 68 ° C., 100% (dew point of the free running section: 68 ° C.), and the absolute humidity was 0.182 kg / m 3 . The product of the absolute humidity [kg / m 3 ] of the idling atmosphere and the idling time [s] was 0.1092. When continuous spinning was performed for 24 hours in this state, no condensation of water vapor was observed on the lower surface of the nozzle, and stable continuous spinning was possible.
[0030]
The obtained hollow fiber membrane was immersed in a 1000 mg / L sodium hypochlorite aqueous solution at 40 ° C. for 12 hours, then immersed in water at 60 ° C. for 1 hour, washed, and then dried at 60 ° C. for 3 hours.
The outer diameter of the obtained hollow fiber membrane was 1.2 mm, the inner diameter was 0.8 mm, and the pure water permeability coefficient indicating the permeability was 180 (m 3 / m 2 / hr / MPa). The maximum pore diameter pressure measured using 99.5% ethanol as a measurement medium based on the method of ASTM F316-140 was 140 kPa (converted pore diameter of about 0.45 μm), and the average pore diameter pressure was 190 kPa (converted pore diameter of about 0.35 μm). )Met. When the outer surface of this membrane was observed with an electron microscope (SEM), a mesh-like hole of about 2 μm was observed, and it was confirmed that the separation active layer was moved from the membrane surface to the inside.
[0031]
Further, when a quality inspection (measurement of the number of defects) in the hollow fiber membrane 10m was performed by a bubble point method (measurement medium: 99.5% ethanol), pores having a diameter of 80 kPa or less (a converted pore diameter of about 0.8 μm or more) were measured. Was not done.
[0032]
As described above, according to the present invention, it can be understood that a porous hollow fiber membrane exhibiting high permeation performance and having excellent spinning stability and membrane quality can be easily obtained.
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002186636A JP2004025066A (en) | 2002-06-26 | 2002-06-26 | Method for manufacturing porous hollow fiber membrane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002186636A JP2004025066A (en) | 2002-06-26 | 2002-06-26 | Method for manufacturing porous hollow fiber membrane |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2004025066A true JP2004025066A (en) | 2004-01-29 |
Family
ID=31181932
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002186636A Pending JP2004025066A (en) | 2002-06-26 | 2002-06-26 | Method for manufacturing porous hollow fiber membrane |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2004025066A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008194647A (en) * | 2007-02-15 | 2008-08-28 | Toyobo Co Ltd | Hollow fiber membrane |
| JP2010522807A (en) * | 2007-03-28 | 2010-07-08 | スリーエム イノベイティブ プロパティズ カンパニー | Method for forming microporous membrane |
| JP2012082396A (en) * | 2010-09-13 | 2012-04-26 | Mitsubishi Rayon Co Ltd | Method of manufacturing porous film |
| KR102022264B1 (en) * | 2018-05-28 | 2019-09-18 | 주식회사 마이크로필터 | Manufacturing Method of Hollow Fiber Membrane using Organic acids |
-
2002
- 2002-06-26 JP JP2002186636A patent/JP2004025066A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008194647A (en) * | 2007-02-15 | 2008-08-28 | Toyobo Co Ltd | Hollow fiber membrane |
| JP2010522807A (en) * | 2007-03-28 | 2010-07-08 | スリーエム イノベイティブ プロパティズ カンパニー | Method for forming microporous membrane |
| JP2012082396A (en) * | 2010-09-13 | 2012-04-26 | Mitsubishi Rayon Co Ltd | Method of manufacturing porous film |
| KR102022264B1 (en) * | 2018-05-28 | 2019-09-18 | 주식회사 마이크로필터 | Manufacturing Method of Hollow Fiber Membrane using Organic acids |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2145451C (en) | Process for producing composite membranes | |
| JP5648633B2 (en) | Method for producing porous membrane | |
| KR20090013643A (en) | Polyvinylidene difluoride hollow fiber membrane for water treatment and manufacturing method thereof | |
| WO2017043233A1 (en) | Film-forming stock solution for use in non-solvent-induced phase separation methods, and method for producing porous hollow fiber membrane using same | |
| JP2006528057A (en) | Monolithically skinned asymmetric membrane with solvent resistance | |
| CN104271651A (en) | Porous membrane production method, and porous membrane drying device | |
| JP4084103B2 (en) | Method and apparatus for producing porous hollow fiber membrane | |
| JP5983981B2 (en) | Method for producing porous membrane | |
| JP5553699B2 (en) | Polyamide moisture permeable membrane and method for producing the same | |
| JP2004025066A (en) | Method for manufacturing porous hollow fiber membrane | |
| JPS60246812A (en) | Hollow polysulfone based resin fiber | |
| JP7122202B2 (en) | Water vapor separation membrane and method for producing water vapor separation membrane | |
| JP2009226397A (en) | Hollow fiber membrane for humidification and membrane module for humidification | |
| KR100581206B1 (en) | Polyvinylidene fluoride Porous Hollow Fiber Membrane and the Manufacturing Process thereof | |
| KR102139208B1 (en) | A preparation method of fouling-resistant hollow fiber membrane and a fouling-resistant hollow fiber membrane prepared by the same | |
| CN113634140B (en) | Internal support polyvinylidene fluoride hollow dry film and preparation method thereof | |
| JP5473215B2 (en) | Method for producing porous membrane for water treatment | |
| JP2005042074A (en) | Production method for porous membrane | |
| JP4013396B2 (en) | Method for producing porous polyamideimide hollow fiber membrane | |
| JPWO2011010690A1 (en) | Method for producing porous membrane | |
| JP2002517326A (en) | Method for producing cellulosic molded article | |
| JPH03174233A (en) | Production of aromatic polysulfone hollow-fiber membrane | |
| JP2023552734A (en) | Hollow fiber membrane and its manufacturing method | |
| JP2005211784A (en) | Porous membrane and manufacturing method therefor | |
| JPS6120644B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20050623 |
|
| A977 | Report on retrieval |
Effective date: 20070528 Free format text: JAPANESE INTERMEDIATE CODE: A971007 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070605 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20071106 |