JP2530133B2 - Microporous membrane - Google Patents
Microporous membraneInfo
- Publication number
- JP2530133B2 JP2530133B2 JP61285997A JP28599786A JP2530133B2 JP 2530133 B2 JP2530133 B2 JP 2530133B2 JP 61285997 A JP61285997 A JP 61285997A JP 28599786 A JP28599786 A JP 28599786A JP 2530133 B2 JP2530133 B2 JP 2530133B2
- Authority
- JP
- Japan
- Prior art keywords
- membrane
- film
- pore size
- solvent
- microporous membrane
- 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.)
- Expired - Fee Related
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Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
- Filtering Materials (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Moulding By Coating Moulds (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は流体（液体）濾過用微孔性膜に関するもので
あり、特に製薬工業における薬剤，食品工業におけるア
ルコール飲料，前記製造工業及び半導体製造工業を始め
とする微細な加工を行う電子工業分野，さらに諸工業の
実験室等において使用される超純水製造のための精製
水，純水等の濾過、その他の精密濾過に用いられ、10μ
ｍ以下特に１μｍ以下サブミクロンオーダーの微粒子や
微生物を効率よく濾過する精密濾過用微孔性膜に関する
ものである。TECHNICAL FIELD The present invention relates to a microporous membrane for fluid (liquid) filtration, and particularly to a drug in the pharmaceutical industry, an alcoholic beverage in the food industry, the manufacturing industry and semiconductor manufacturing. Used in the field of electronics, which performs fine processing such as industry, and in the laboratory of various industries. It is used for the purification of ultrapure water, the purification of pure water, the filtration of pure water, and other microfiltration.
The present invention relates to a microporous membrane for microfiltration that efficiently filters fine particles and microorganisms of m or less, particularly 1 μm or less and submicron order.
従来製薬工業，食品工業，電子工業分野において用い
られる精密濾過用微孔性膜およその製造方法に関しては
セルロースエステル，脂肪族ポリアミド，ポリフルオロ
カーボン，ポリスルホン，ポリプロピレン等を原料とす
るものが開示されている（例えば特公昭48−40050号，
特開昭58−37842号，特開昭58−91732号，特開昭56−15
4051号各公報参照）。Conventionally, microporous membranes for microfiltration that have been used in the fields of pharmaceutical industry, food industry, and electronics industry have been disclosed as a method for producing microporous membranes using cellulose ester, aliphatic polyamide, polyfluorocarbon, polysulfone, polypropylene, etc. as raw materials. (For example, Japanese Patent Publication No. 48-40050,
JP-A-58-37842, JP-A-58-91732, JP-A-56-15
See each bulletin of No. 4051).
このような微孔性膜は、その内部に存在する微孔の孔
径が膜厚方向に実質的に変化せず、膜の両表面の孔径が
実質的に換わらない所謂対称膜と、膜厚方向に孔径が連
続的または不連続的に変化し、膜の一方の表面の孔径と
他方の表面の孔径とが異なつている所謂非対称膜と呼ば
れる構造を有するものとに分類される。Such a microporous membrane has a so-called symmetric membrane in which the pore diameters of the micropores present inside do not substantially change in the film thickness direction and the pore diameters of both surfaces of the membrane do not substantially change, and It is classified into a so-called asymmetric membrane having a structure in which the pore diameter changes continuously or discontinuously, and the pore diameter on one surface of the membrane is different from the pore diameter on the other surface.
これらのうち対称膜は、特開昭58−98015号に記述さ
れているが、濾過にあたつて膜全体が流体の流れに対し
て大きな抵抗を示し、小さな流速しか得られない（即
ち、単位面積当たり、単位時間当たり単位差圧当たり小
さな流量しか得られない）上、目詰まりがしやすく濾過
寿命が短い、耐ブロッキング性がない等の欠点があつ
た。Of these, the symmetrical membrane is described in JP-A-58-98015, but the entire membrane exhibits a large resistance to the flow of fluid during filtration and only a small flow velocity can be obtained (that is, the unit Only a small flow rate can be obtained per unit area and per unit pressure difference per unit time), and there are drawbacks such as easy clogging, short filtration life, and no blocking resistance.
一方非対称膜は特公昭55−6406号，特開昭56−14051
号に記載されている如く緻密層と呼ばれる孔径の小さい
層を膜の片方の表面にもち比較的大きな穴をもう一つの
表面にもつたものである。これを濾過液の流れに対し孔
径の大きい面を向けると実質的には濾過除去されるる最
小の微粒子はこの緻密層で捕捉されるというように、膜
の厚みをすべて有効に濾材として活用することができる
ので、注意深く使用する場合には、濾過流量を増加せし
めることも膜の寿命を延ばすことも可能であり、この意
味で優れた微孔性膜である。On the other hand, the asymmetric membrane is disclosed in Japanese Examined Patent Publication No. 55-6406 and Japanese Unexamined Patent Publication No. 56-14051.
As described in No. 3, a layer having a small pore size called a dense layer is provided on one surface of the membrane and a relatively large hole is provided on the other surface. When this is directed to the surface of the filtrate that has a large pore size, the smallest particles that are substantially filtered out are captured in this dense layer, so that the entire membrane thickness is effectively utilized as a filter medium. Therefore, when used carefully, it is possible to increase the filtration flow rate and prolong the life of the membrane, and in this sense, it is an excellent microporous membrane.
しかしながら、この場合には緻密層が極めて重要であ
るにもかかわらず従来、この緻密層が表面にあるために
擦過その他で傷がつきやすく、微粒子の漏洩をきたし易
いという欠点があつた。However, in this case, despite the fact that the dense layer is extremely important, there has been a drawback that the dense layer is present on the surface, so that it is easily scratched by rubbing or the like and easily causes leakage of fine particles.
かかる欠点を補うために、緻密層即ち孔径の小さな層
が濾過膜内面に存在する構造が望まれ、特開昭58−1504
02号には非対称膜を２枚緻密層同士を密着し重ね合わせ
る不連続な構造が提案されている。しかしながら、この
ように２枚の非対称膜を重ねる濾過系では、ひだ折りに
してカートリッジに納めた場合には、カートリッジ内の
濾過面積が小さくなり、モジュールとしての濾過流量が
小さくなるという欠点がある。このような理由で当業界
では単一の膜内に緻密層を有する構造を実現することが
強く望まれていた。In order to make up for such drawbacks, a structure in which a dense layer, that is, a layer having a small pore size is present on the inner surface of the filtration membrane is desired.
No. 02 proposes a discontinuous structure in which two dense layers of asymmetric membranes are closely adhered to each other and overlap each other. However, such a filtration system in which two asymmetric membranes are superposed has a drawback that the filtration area in the cartridge becomes small when the folds are placed in the cartridge, and the filtration flow rate as a module becomes small. For this reason, it has been strongly desired in the art to realize a structure having a dense layer in a single film.
本発明者等は上記の欠点を解決すべく、従来微孔性膜
製造における１つの方法とされいた、ポリマー原液を流
延後空気中に一定時間放置することによりミクロ相分離
を起こさせ、微孔の孔径を制御するドライウエツト法と
いう技術について詳細に検討した結果、溶媒を十分に蒸
発させる方法（例えば特開昭55−102416号）、及び溶媒
を殆ど蒸発させることなく凝固浴に浸漬する方法（例え
ば特開昭55−8887号及び同56−154051号）の何れとも異
なり、適度に溶媒の蒸発と非溶媒蒸気の吸収量を制御し
た場合には、驚くべきことに、微孔性膜の膜面垂直方向
の内部に最小孔径層を形成し得る事を見い出した。In order to solve the above-mentioned drawbacks, the present inventors have made it possible to cause microphase separation by leaving a polymer undiluted solution in the air for a certain period of time after casting, which has been considered as one method in the production of microporous membranes. As a result of detailed examination of a technique called a dry wet method for controlling the pore diameter of the pores, a method of sufficiently evaporating the solvent (for example, JP-A-55-102416) and a method of immersing the solvent in the coagulation bath with almost no evaporation ( For example, unlike both JP-A-55-8888 and JP-A-56-154051, when the evaporation of the solvent and the absorption amount of the non-solvent vapor are controlled appropriately, the film of the microporous film is surprising. It has been found that a minimum pore size layer can be formed inside the surface in the vertical direction.
また本発明者等は、濾過と目づまりの機構および比表
面積と濾過寿命との関係を解析し、 膜の構造を極度
に非対称にすると膜の比表面積が小さくなり、最小孔径
層より上流のインレツト側の部分がプレフイルターとし
て有効に働かない事、および 捕捉される粒子は必ず
しも粒子径より小さな孔径部分で捕捉されるわけではな
く、その多くは膜の内部の壁面に付着して捕捉されてい
るという事の２点が、濾過寿命に関係した重要な因子と
なる事、従つて、極度な非対称膜を作らず、膜の比表面
積を大きくすることにより濾過寿命を延ばすことが合理
的であることを見い出し、さらに鋭意研究した結果、製
膜現役を流延してから凝固液に浸漬するまでの間で、溶
媒の蒸発と、雰囲気から吸収する非溶媒の量を制御する
ことにより、8m2/g以上の比表面積を実現することがで
き、これによつて微孔性膜の寿命を延ばすことができる
ことを見い出し、かゝる微孔性膜について先に出願を行
つた。（特開昭61−148192号） 本発明は、先に出願した微孔性膜の改良に関し、優れ
た性能を発揮する微孔性膜を提供することを目的とする
ものである。Further, the present inventors analyzed the mechanism of filtration and clogging and the relationship between the specific surface area and the filtration life, and when the structure of the membrane was made extremely asymmetric, the specific surface area of the membrane became small, and the inlet side upstream of the minimum pore size layer Part does not work effectively as a prefilter, and the particles to be trapped are not necessarily trapped in the pore size smaller than the particle size, but most of them are trapped on the inner wall surface of the membrane. Two things are important factors related to filtration life. Therefore, it is rational to extend filtration life by increasing the specific surface area of the membrane without forming an extremely asymmetric membrane. As a result of discovering and further diligent research, by controlling the evaporation of the solvent and the amount of the non-solvent absorbed from the atmosphere between the casting of the film forming active material and the immersion in the coagulating liquid, 8 m 2 / g Ratio above Can be realized area, found that it is possible to extend the life of O connexion microporous membrane thereto, KoTsuta the previously filed for Such microporous membranes. (JP-A-61-148192) The present invention relates to the improvement of the microporous membrane previously filed, and an object thereof is to provide a microporous membrane exhibiting excellent performance.
従つて本発明の第１の目的は、濾過抵抗が小さく濾過
流量の大きい微孔性膜を提供することである。Therefore, the first object of the present invention is to provide a microporous membrane having a low filtration resistance and a high filtration flow rate.
本発明の第２の目的は、表面の欠損によつても濾過性
能が劣化しにくい微孔性膜を提供することにある。A second object of the present invention is to provide a microporous membrane in which the filtration performance is less likely to deteriorate due to surface defects.
又、本発明の第３の目的は、微粒子ならびに細菌等を
効率良く捕捉することができる、濾過寿命の長い微孔性
膜を提供することにある。A third object of the present invention is to provide a microporous membrane having a long filtration life, which can efficiently capture fine particles and bacteria.
即ち本発明の要旨は平均粒径に対し緻密層の最大孔径
を出来る限り大きくしない方が漏洩粒子径も小さくな
り、好ましいという観点に立ち、内部緻密層膜によつて
せまい孔径分布で再孔径が平均孔径の２倍以下にするこ
が出来るということに着目した。ちなみに市販されてい
る膜は最大孔径は平均孔径の２倍以上のものである。That is, the gist of the present invention is that it is preferable that the maximum pore size of the dense layer is not as large as possible with respect to the average particle size, since the leaking particle size is also small, which is preferable. We paid attention to the fact that the average pore size can be made twice or less. By the way, the maximum pore size of the commercially available membrane is more than twice the average pore size.
本発明の上記の目的は、膜厚方向に孔径分布を有し膜
内部に最小孔径層を有する流体（液体）濾過用微孔性膜
において、ASTM−316−80の方法によって測定した微孔
性膜の孔径の最大孔径が平均孔径の1.8倍以下であり、
ポリスルホンおよび／またはポリエーテルスルホンを膜
形成ポリマーとすることを特徴とする流体（液体）濾過
用微孔性膜によつて達成された。前記測定法によれば緻
密層の孔径が最大孔径／平均孔径＜1.8の関係にある緻
密層を意味する。The above object of the present invention is to provide a microporous membrane for fluid (liquid) filtration having a pore size distribution in the film thickness direction and having a minimum pore size layer inside the membrane, the microporosity measured by the method of ASTM-316-80. The maximum pore size of the membrane is 1.8 times or less than the average pore size,
It has been achieved by a microporous membrane for fluid (liquid) filtration, characterized in that polysulfone and / or polyether sulfone are the membrane-forming polymers. According to the above-mentioned measuring method, it means a dense layer in which the pore diameter of the dense layer has a relationship of maximum pore diameter / average pore diameter <1.8.
本発明の微孔性膜の製造方法の実施態様を第３図を用
いて説明する。An embodiment of the method for producing a microporous membrane of the present invention will be described with reference to FIG.
第３図において、ポリマーをジヤケツト付溶解釜１で
溶解する。その時微細孔形成に必要な非溶媒，膨潤剤等
が添加混合される。この溶液は脱泡後、送液ポンプ２に
より流延用の注液器３に送られ、注液器３より流延用支
持体４としてのポリエステルフイルム上に安定した溶液
状態の溶液を液膜５として流延する。流延された液膜５
の表面に空気調節装置６で温度15〜60℃，相対湿度10〜
80％，風速0.2〜4m/secの範囲内で調節した空気を吹出
口７より２〜17秒間当てた後、ポリマーに対し非溶媒で
ありポリマーの溶液に相溶性を有する液を収容する凝固
液槽８に浸漬させる。In FIG. 3, the polymer is melted in a melting kettle 1 with a jacket. At that time, a nonsolvent necessary for forming fine pores, a swelling agent, etc. are added and mixed. After degassing, this solution is sent to a casting liquid injector 3 by a liquid feed pump 2, and a stable solution state solution is formed on the polyester film as the casting support 4 from the liquid injector 3 into a liquid film. Cast as 5. Liquid film cast 5
On the surface of the air conditioning device 6 temperature 15 ~ 60 ℃, relative humidity 10 ~
A coagulating liquid containing a liquid that is a non-solvent for the polymer and is compatible with the polymer solution after applying 80% air at a velocity of 0.2 to 4 m / sec for 2 to 17 seconds from the outlet 7. Immerse in the bath 8.
液膜５は流延後調節した空気に吹かれることによつて
液膜の表面から内部に向つてコアセルベーシヨンを起こ
し、微細なコアセルベーシヨン相を液膜５の表面から内
部に向つて形成し、凝固液槽８の中でその微細なコアセ
ルベーシヨン相を微細孔として固定させると同時に液膜
５の相分離によつて、微細孔以外の細孔を形成し、微孔
性膜９を形成する。しかる後、微孔性膜９を流延用支持
体４より剥離させる。After being cast, the liquid film 5 is blown by the conditioned air to cause coacervation from the surface of the liquid film toward the inside, and a fine coacervation phase is directed from the surface of the liquid film 5 toward the inside. Then, the fine coacervation phase is fixed in the coagulation liquid tank 8 as fine pores, and at the same time, by the phase separation of the liquid film 5, fine pores other than the fine pores are formed. The film 9 is formed. After that, the microporous film 9 is peeled from the casting support 4.
流延用支持体４は流延用支持体巻取機10へ、剥離した
微孔性膜９は水洗槽11,乾燥機12を経て巻取機13に巻取
られる。The casting support 4 is taken up by the casting support take-up machine 10, and the peeled microporous membrane 9 is taken up by the take-up machine 13 after passing through the washing tank 11 and the dryer 12.
上記の製造方法により、そして風の吹きつける時間を
換えることによつて希望の平均孔径の微孔性膜を最大孔
径／平均孔径＜1.8の条件でつくることができる。By the above production method and by changing the blowing time, a microporous membrane having a desired average pore size can be produced under the condition of maximum pore size / average pore size <1.8.
本発明において用いられる膜形成用ポリマーはポリス
ルホンおよび／またはポリエーテルスルホンを膜形成用
ポリマーとすることが好ましく、 または の繰り返し単位で表されるポリマーが好ましい。本発明
の微孔性膜の製造は、上記ポリマーを．良溶媒、．
良溶媒の混合溶媒または．ポリマーに対する溶解性の
程度が異なる複数種の溶媒の混合したものに溶解して製
膜原液を作製し、これを流延用支持体上に流延し、凝固
液に浸透し凝固せしめて製膜した後、洗浄，乾燥して行
う。The film-forming polymer used in the present invention is preferably polysulfone and / or polyether sulfone as the film-forming polymer, Or Polymers represented by repeating units of are preferred. The microporous membrane of the present invention can be prepared by using the above polymer. Good solvent ,.
Mixed solvent of good solvent or. Dissolve in a mixture of multiple solvents with different degrees of solubility in polymers to prepare a stock solution for film formation, cast this solution on a casting support, permeate into the coagulation solution and solidify it to form a film. After that, wash and dry.
この場合の膜形成用ポリマーの溶媒は、膜形成用ポリ
マーの種類等により異なるが、通常膜形成用ポリマーの
溶媒であり、かつ凝固浴に浸漬した場合や速やかに凝固
液と置換されるものが使用される。多くの場合、凝固液
としては水及び／又は水と相溶する有機溶媒が使用され
るので、凝固液と相溶性のある極性溶媒を使用すること
が好ましい。例えば、膜形成用ポリマーがポリスルホン
の場合、ジオキサン、テトラヒドロフラン、ジメチルホ
ルムアミド、ジメチルアセトアミド、Ｎ−メチル−２−
ピロリドンあるいはこれらの混合溶媒が適当である。
又、ポリアクリロニトリルの場合には、ジオキサン、Ｎ
−メチル−２−ピロリドン、ジメチルホルムアミド、ジ
メチルアセトアミド、ジメチルスルホキシド等が、ポリ
アミドの場合にはジメチルホルムアミドやジメチルアセ
トアミド等が、セルロースアセテートの場合は、アセト
ン、ジオキサン、テトラヒドロフラン、Ｎ−メチル−２
−ピロリドン等が適当である。The solvent for the film-forming polymer in this case differs depending on the type of the film-forming polymer, etc., but is usually the solvent for the film-forming polymer, and when it is immersed in the coagulation bath or is quickly replaced with the coagulating liquid. used. In many cases, as the coagulating liquid, water and / or an organic solvent compatible with water is used, and therefore it is preferable to use a polar solvent that is compatible with the coagulating liquid. For example, when the film-forming polymer is polysulfone, dioxane, tetrahydrofuran, dimethylformamide, dimethylacetamide, N-methyl-2-
Pyrrolidone or a mixed solvent thereof is suitable.
In the case of polyacrylonitrile, dioxane, N
-Methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, etc .; in the case of polyamide, dimethylformamide, dimethylacetamide, etc .; in the case of cellulose acetate, acetone, dioxane, tetrahydrofuran, N-methyl-2.
-Pyrrolidone and the like are suitable.
非溶媒を混合する場合の非溶媒としては、水，セルソ
ルブ類，メタノール，エタノール，プロパノール、アセ
トン，テトラヒドロフラン，ポリエチレングリコール，
グリセリン等があげられる。As the non-solvent when the non-solvent is mixed, water, cellosolves, methanol, ethanol, propanol, acetone, tetrahydrofuran, polyethylene glycol,
Examples include glycerin.
非溶媒の良溶媒に対する割合は、混合液が均一状態を
保てる範囲ならば如何なる範囲でもよいが、重量％で５
〜50％が好ましい。The ratio of the non-solvent to the good solvent may be any range as long as the mixed solution can maintain a uniform state, but it is 5% by weight.
~ 50% is preferred.
また、多孔質構造を制御するものとして膨潤剤と称さ
れる無機電解質、有機電解質または高分子又はその電解
質をポリマー溶液に加える。Further, an inorganic electrolyte, an organic electrolyte, or a polymer or its electrolyte, which is called a swelling agent, is added to the polymer solution for controlling the porous structure.
膨潤剤としては、食塩、塩化リチウム、硝酸ナトリウ
ム、硝酸カリウム、硫酸ナトリウム、塩化亜鉛等の無機
酸の金属塩、酢酸ナトリウム、ギ酸ナトリウム等の有機
酸の金属塩、ポリエチレングリコール、ポリビニルピロ
リド等の高分子、ポリスチレンスルホン酸ナトリウム、
ポリビニルベンジルトリメチルアンモニウムクロライド
等の高分子電解質、ジオクチルスルホコハク酸ナトリウ
ム、アルキルメチルタウリン酸ナトリウム等のイオン系
界面活性剤等が用いられる。これらの膨潤剤は、単独で
溶液に加えてもある程度の効果を示すが、これら膨潤剤
を水溶液として添加する時に、特に顕著な効果を示すも
のである。膨潤剤水溶液の添加量は添加によつて溶液の
均一性が失われることがない限り、特に制限はないが、
通常、溶媒に対して0.5容量％〜10容量％である。また
膨潤剤水溶液の濃度についても特に制限はなく、濃度の
大きい方が効果が大きいが、通常用いられる濃度として
は１重量％〜60重量％である。As the swelling agent, metal salts of inorganic acids such as sodium chloride, lithium chloride, sodium nitrate, potassium nitrate, sodium sulfate and zinc chloride, metal salts of organic acids such as sodium acetate and sodium formate, polyethylene glycol, polyvinylpyrrolid and the like. Molecule, sodium polystyrene sulfonate,
A polyelectrolyte such as polyvinylbenzyltrimethylammonium chloride and an ionic surfactant such as sodium dioctylsulfosuccinate and sodium alkylmethyl taurate are used. These swelling agents show some effects even when added alone to the solution, but when these swelling agents are added as an aqueous solution, they show particularly remarkable effects. The addition amount of the swelling agent aqueous solution is not particularly limited as long as the addition does not lose the homogeneity of the solution.
Usually, it is 0.5% by volume to 10% by volume with respect to the solvent. The concentration of the swelling agent aqueous solution is not particularly limited, and the higher the concentration, the greater the effect, but the concentration usually used is 1% by weight to 60% by weight.
製膜原液としてのポリマー溶液の濃度は５〜35重量
％、好ましくは10〜30重量％である。35重量％を超える
と、得られる微孔性膜の透水性が実用的な意味を持たな
い程小さくなり、また５重量％より低い濃度では十分な
分離能を持つた微孔性膜は得られない。The concentration of the polymer solution as a film-forming stock solution is 5 to 35% by weight, preferably 10 to 30% by weight. If it exceeds 35% by weight, the water permeability of the obtained microporous membrane becomes so small that it has no practical meaning, and if it is less than 5% by weight, a microporous membrane having sufficient separation ability is obtained. Absent.
本発明の微孔性膜の製造方法は、上記の如くして得ら
れた製膜原液を流延支持体上に流延し、流延した液の表
面に温度15〜60℃，相対湿度10〜80％，風速0.2〜4m/se
cの範囲で調節した空気を２〜17秒間当てることによ
り、溶媒蒸気の蒸発量と雰囲気からの非溶媒蒸気吸収量
（湿分の吸収）を適宜調節することに重要な技術があ
る。このような調整は、例えば製膜原液を流延支持体上
に流延し、絶対湿度2gH O/kgAir以上の空気を0.2m/sec
以上の風速で流延面に当てることによつて、液膜の最表
面層から１μｍ以上、好ましくは１〜30μｍの深さにコ
アセルベーシヨン相を形成させることが出来る。その後
直ちに凝固浴槽に浸漬し多孔性膜を形成させる。このよ
うにして得られた膜は、コアセルベーシヨンを起こさせ
た部分の最深部が最小孔径層となる。The method for producing a microporous membrane of the present invention is carried out by casting a film-forming stock solution obtained as described above on a casting support, and the surface of the cast solution is at a temperature of 15 to 60 ° C. and a relative humidity of 10. ~ 80%, wind speed 0.2 ~ 4m / se
There is an important technique for appropriately adjusting the evaporation amount of solvent vapor and the non-solvent vapor absorption amount (absorption of moisture) from the atmosphere by applying air adjusted in the range of c for 2 to 17 seconds. Such adjustment is performed, for example, by casting a film-forming stock solution on a casting support and applying an air having an absolute humidity of 2 gH O / kg Air or more at 0.2 m / sec.
By contacting the casting surface with the above wind speed, the coacervation phase can be formed at a depth of 1 μm or more, preferably 1 to 30 μm from the outermost surface layer of the liquid film. Immediately thereafter, it is immersed in a coagulation bath to form a porous film. In the film thus obtained, the deepest part of the portion where the coacervation is caused becomes the minimum pore size layer.
本発明の膜の表面の孔径に対して裏面の孔径は10〜10
00倍程度、またBET法で測定したその比表面積は8m2/g以
上である。本発明においては、さらに比表面積は８〜80
m2/gが得られるが、特に好ましくは20〜60m2/gである。
比表面積を80m2/g以上にすると膜の機械的強度が実用の
限界を越えるほど低下する欠点がある。The pore diameter on the back surface is 10 to 10 relative to the pore diameter on the front surface of the membrane of the present invention.
It is about 00 times and its specific surface area measured by the BET method is 8 m 2 / g or more. In the present invention, the specific surface area is 8 to 80.
m 2 / g but is obtained, particularly preferably 20~60m 2 / g.
If the specific surface area is 80 m 2 / g or more, the mechanical strength of the film will be so low that it exceeds the practical limit.
この理由は必ずしも明確ではないが次のように推定す
ることができる。即ち、最小孔径層は溶媒の蒸発と非溶
媒の進入によりミクロ相分離が起こつた層と起こらない
層の境界に生ずると考えられるが、この最小孔径層の孔
径が成長して大きくなる前に凝固液に浸漬した場合に
は、この最小孔径層を固定することができる。次に、凝
固液が上記最小孔径層を通して流延膜内部に浸透する速
度は緩慢であるので、最小孔径層より内部（裏面側に向
つて）裏面の非溶媒への進入によるミクロ相分離が進行
した結果、最小孔径層の孔径より大きな孔径を有する微
孔が生ずる。The reason for this is not always clear, but it can be estimated as follows. That is, it is considered that the minimum pore size layer occurs at the boundary between the layer in which microphase separation occurs and the layer in which the microphase separation does not occur due to the evaporation of the solvent and the entry of the non-solvent, but the minimum pore size layer solidifies before the pore size grows and becomes larger. When immersed in a liquid, this minimum pore size layer can be fixed. Next, since the coagulation liquid permeates through the minimum pore size layer into the casting membrane at a slow rate, microphase separation proceeds inside the minimum pore size layer (towards the back surface side) by entering the non-solvent on the back surface. As a result, micropores having a pore size larger than that of the minimum pore size layer are generated.
精密濾過の領域に供される膜の表面を開孔させるた
め、従来は、成膜する原液をわずに相分離させた状態で
支持体上へ流延し、凝固液に浸漬する方法が用いられて
いた（例えば、特開昭56−154051号及び特開昭58−1457
40号公報）。In order to open the surface of the membrane used in the microfiltration area, the conventional method is to cast the raw solution for film formation on the support without phase separation and immerse it in the coagulation solution. (For example, JP-A-56-154051 and JP-A-58-1457).
No. 40 bulletin).
しかしながら、これらの最大の欠点は相分離状態での
成膜原液の安定性が極めて悪く、調整後短時間で流延成
膜を行わなければ、原液中に沈澱が起こり、特開昭58−
145740号公報に開示されているように、更に濾過工程を
必要とする事態を生ずる点にある。一方、原液の安定性
を保つために相分離を押さえてしまうと、表面にスキン
層が生じ精密濾過膜として適さない。これに対し本発明
の製造方法は、成膜原液を全くう均一な系として調整
し、流延してか凝固液に浸漬するまでの間で、例えば空
気中から非溶媒蒸気（例えば水分）を吸収せしめる一方
で溶媒を蒸発させ、表面近傍にのみ相分離状態を作り出
し、凝固浴に浸漬するものであるので上記の欠点がな
い。However, the biggest drawback of these is that the stability of the film-forming stock solution in the phase-separated state is extremely poor.
As disclosed in Japanese Patent No. 145740, there is a point that a further filtration step is required. On the other hand, if phase separation is suppressed in order to maintain the stability of the stock solution, a skin layer will be formed on the surface and it will not be suitable as a microfiltration membrane. On the other hand, in the production method of the present invention, a non-solvent vapor (for example, moisture) is removed from the air, for example, during preparation of the film-forming stock solution as a completely homogeneous system and casting or dipping in the coagulating solution. Since the solvent is evaporated while the solvent is evaporated, a phase separation state is created only in the vicinity of the surface, and it is immersed in the coagulation bath, the above-mentioned drawbacks are not present.
即ち、本発明は、表面に接している空気の温度空気中
の非溶媒蒸気量（水の場合は相対湿度）および流延膜表
面に当てる空気の風速を制御することにより、従来得ら
れたことのない両非対称膜を製造することができる。こ
の場合、風が当つた表面層付近にのみ相分離をおこさせ
るために、極めて短時間に、均一な非溶媒蒸気の吸収を
おこさせ直ちに凝固させる必要がある。この非溶媒蒸気
の吸収を調節することにより、緻密層の深さおよびその
孔径を調節するこができる。That is, the present invention has been conventionally obtained by controlling the temperature of the air in contact with the surface, the amount of non-solvent vapor in the air (relative humidity in the case of water), and the wind speed of the air applied to the surface of the casting film. Both asymmetric membranes without can be produced. In this case, in order to cause phase separation only in the vicinity of the surface layer exposed to the wind, it is necessary to cause uniform non-solvent vapor absorption in an extremely short time and immediately solidify. By adjusting the absorption of this non-solvent vapor, the depth of the dense layer and its pore size can be adjusted.
また本発明を効果的にするためには特に製膜原液中に
ポリマーの良溶媒だけでなく、非溶媒や膨潤剤をあらか
じめ加えておくことが必要である。これらの非溶媒や膨
潤剤としては、例えば、前述の水，ポリエチレングリコ
ール，そしてポリビニルピロリドン，等をあげることが
できる。Further, in order to make the present invention effective, it is necessary to add not only a good solvent for the polymer but also a non-solvent or a swelling agent to the stock solution for film formation in advance. Examples of these non-solvents and swelling agents include water, polyethylene glycol, polyvinylpyrrolidone, and the like as described above.
上記の製造条件は、ポリマー種、溶媒種、非溶媒種、
膨潤剤種ポリマー濃度および流延時の雰囲気等により異
なるので、ミクロ相分離の時間と、膜の構造を検討し、
最適の条件を見い出す必要がある。見い出された条件
は、流延膜からの溶媒の蒸発量と非溶媒蒸気の吸収量を
種々の方法により調節することによつて制御することが
できる。The above production conditions are polymer species, solvent species, non-solvent species,
Since it depends on the swelling agent polymer concentration, the atmosphere during casting, etc., consider the microphase separation time and the structure of the membrane.
It is necessary to find the optimal conditions. The conditions found can be controlled by adjusting the evaporation of solvent and the absorption of non-solvent vapor from the cast film by various methods.
流延膜から一定量の溶媒が蒸発し、一定量の非溶媒蒸
気を吸収するように調節する方法としては、流延部から
凝固液までのポリマー溶液の経路に覆いをかけて、流延
後凝固浴に浸漬するまでの時間を調節したり、この雰囲
気の溶媒蒸気圧、非溶媒蒸気圧、温度並びに送風、排風
速度等を調節するなどの方法を取ることができる。As a method of adjusting so that a certain amount of solvent evaporates from the casting film and absorbs a certain amount of non-solvent vapor, cover the polymer solution path from the casting part to the coagulating liquid, and after casting It is possible to adjust the time until it is immersed in the coagulation bath, or to adjust the solvent vapor pressure, non-solvent vapor pressure, temperature, blowing air, exhaust air velocity, etc. of this atmosphere.
凝固液から離脱したポリマー溶液は自己支持性をもつ
に至り、補強のため密着していた支持体から剥離されて
水洗浴に浸漬される。水洗後は乾燥し、捲き取るか、ま
たは親水化などの後処理が行われる。この様にして膜の
内部に微細孔を有し、両表面側に比較的大きな細孔の濾
過膜を製造することが出来る。The polymer solution released from the coagulation liquid reaches a self-supporting property, and is peeled from the adhered support for reinforcement and immersed in a washing bath. After washing with water, it is dried, wound up, or subjected to a post-treatment such as hydrophilization. In this way, a filtration membrane having fine pores inside and relatively large pores on both surface sides can be manufactured.
以下、本発明の実施例を示すが、本発明はこれに限定
されるものではない。Examples of the present invention will be shown below, but the present invention is not limited thereto.
実施例−１〜４ 比較例１ ポリスルホン（UCC社製 Ｐ−3500）15部,N−メチル
−２−ピロリドン 70部，ポリビニルピロリドン 15
部，水３部を均一に溶解して製膜原液を得る。ガラス板
上に安定した溶液状態で製品厚さ180μｍになるようキ
ヤステイングコーターを通して流延し、25℃相対湿度40
％に調節した空気を風速1.2m/secで流延した液膜表面に
当てた後、直ちに25℃の水を満たした凝固浴槽へ浸漬し
て微孔製膜を得た。Examples-1 to 4 Comparative Example 1 Polysulfone (P-3500 manufactured by UCC) 15 parts, N-methyl-2-pyrrolidone 70 parts, polyvinylpyrrolidone 15
Parts and 3 parts of water are uniformly dissolved to obtain a film forming stock solution. Cast on a glass plate through a casting coater so that the product thickness is 180 μm in a stable solution state, and the relative humidity is 40 at 25 ℃.
% Air was applied to the surface of the liquid film cast at a wind speed of 1.2 m / sec, and then immediately immersed in a coagulation bath filled with water at 25 ° C. to obtain a microporous film.
風を当てる時間を変化させた時の膜の特性を第１表に
示した。なお、平均孔径測定はASTM−316−80法によ
る。又膜の緻密層の深さは電子顕微鏡によつて測定し
た。Table 1 shows the characteristics of the film when the time of blowing the air was changed. The average pore size is measured by the ASTM-316-80 method. The depth of the dense layer of the film was measured by an electron microscope.
上記のようにいずれの膜もその最大孔径が平均孔径の
1.8媒以下となつている。本発明の微孔性膜は上記の如
く製作することが出来る。 As described above, the maximum pore size of any of the membranes is
It is less than 1.8 medium. The microporous membrane of the present invention can be manufactured as described above.
実施例−５ 比較例−２ 次に表面に最緻密層を有する非対称膜として市販のポ
リスルホン膜の平均孔径と最大孔径を測定したところ平
均孔径の約3.6倍の最大孔径を示した（比較例−２）。
最大孔径が同一になる様に前記実施例１〜４と同様の条
件で風を当てる時間を8.6secとして膜を作り（実施例−
５）、本発明の膜（実施例−５）の孔径分布を市販の膜
（比較例−２）と比較した。結果を第１図に示す。Example-5 Comparative Example-2 Next, when the average pore diameter and the maximum pore diameter of a commercially available polysulfone membrane as an asymmetric membrane having a densest layer on the surface were measured, the maximum pore diameter was about 3.6 times the average pore diameter (Comparative Example- 2).
A membrane was made under the same conditions as in Examples 1 to 4 so that the maximum pore size was the same, and the time of applying air was 8.6 seconds (Example-
5), The pore size distribution of the membrane of the present invention (Example-5) was compared with that of a commercially available membrane (Comparative Example-2). The results are shown in Fig. 1.
また透水速度を比較すると両者とも0.5μｍ以上の粒
径の粒子を除去する膜であるが、市販のポリスルホン膜
は30ml/cm2/min/atmであり、本発明の膜は85ml/cm2/min
/atmと極めて透水量が高く、本発明の構造の膜の特徴を
示すものであつた。Further, comparing the water permeation rates, both are membranes for removing particles having a particle size of 0.5 μm or more, but the commercially available polysulfone membrane is 30 ml / cm 2 / min / atm, and the membrane of the present invention is 85 ml / cm 2 / min
It has a very high water permeability of / atm and shows the characteristics of the membrane of the structure of the present invention.
比較例−3,4 膜構造が対称構造である膜として市販のポリフツ化ビ
ニリデン膜とナイロン膜についてASTM−316−80法によ
り測定した孔径分布を第２図に示した。最大孔径／平均
孔径はナイロン膜＝3.8,ポリフツ化ビニリデン＝2.7と
実施例１に示した本発明の膜に比べ大きな値を示した。Comparative Example-3, 4 The pore size distribution measured by the ASTM-316-80 method for commercially available polyvinylidene fluoride membranes and nylon membranes having a symmetrical membrane structure is shown in FIG. The maximum pore diameter / average pore diameter was nylon membrane = 3.8 and polyvinylidene fluoride = 2.7, which were larger than those of the membrane of the present invention shown in Example 1.
本発明の膜厚方向に孔径分布を有し、膜内部に最小孔
径層を有する流体（液体）濾過用微孔性膜において、微
孔性膜の最大孔径が平均孔径の1.8倍以下であり、ポリ
スルホンおよび／またはポリエーテルスルホンを膜形成
ポリマーとすることを特徴とする流体（液体）濾過用微
孔成膜により、濾過抵抗が小さく濾過流量の大きい、微
粒子ならびに細菌等を効率良く補則できる濾過寿命の長
い微孔性膜を得ることができた。Having a pore size distribution in the film thickness direction of the present invention, in a microporous membrane for fluid (liquid) filtration having a minimum pore size layer inside the membrane, the maximum pore size of the microporous membrane is 1.8 times or less of the average pore size, A micropore film for fluid (liquid) filtration characterized by using polysulfone and / or polyethersulfone as a film-forming polymer, which has a small filtration resistance and a large filtration flow rate, and can efficiently supplement particles and bacteria etc. It was possible to obtain a long length microporous membrane.
さらに最小孔径層が膜の表面ではなく、膜内部に存在
するために、外傷等により損傷される危険性が緩和さ
れ、取り扱い上極めて有利であるのみならず、通常の一
枚の微孔性膜の場合と全く同様にカートリツジ型フイル
ターに使用することもできるので、本発明は極めて有利
である。Furthermore, since the layer having the smallest pore size exists inside the membrane, not on the surface of the membrane, the risk of damage due to external damage is mitigated, and it is extremely advantageous in handling, and it is also an ordinary single microporous membrane. The present invention is extremely advantageous because it can be used in a cartridge type filter just as in the above case.
第１図は本発明の孔径分布についてのグラフ。第２図は
従来の対称構造の孔径分布のグラフである。第３図は本
発明に係わる微孔性膜の製造方法の第１実施例の説明図
である。 １……溶解釜 ２……送液ポンプ、３……注液器 ４……流延用支持体、５……液膜 ６……空気調節装置、７……吹出口 ８……凝固液槽、９……微孔性膜 10……流延用支持体巻取機 11……水洗槽、12……乾燥機 13……巻取機FIG. 1 is a graph of the pore size distribution of the present invention. FIG. 2 is a graph of the pore size distribution of the conventional symmetrical structure. FIG. 3 is an explanatory view of the first embodiment of the method for producing a microporous membrane according to the present invention. 1 ... Melting pot 2 ... Liquid feed pump, 3 ... Liquid injector 4 ... Casting support 5 ... Liquid film 6 ... Air conditioner, 7 ... Air outlet 8 ... Coagulation liquid tank , 9 ... Microporous membrane 10 ... Casting support winding machine 11 ... Washing tank, 12 ... Drying machine 13 ... Winding machine
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭55−129109（ＪＰ，Ａ) 特開 昭59−62305（ＪＰ，Ａ) 特公 平６−76510（ＪＰ，Ｂ２) ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-55-129109 (JP, A) JP-A-59-62305 (JP, A) JP-B 6-76510 (JP, B2)
Claims (1)
径層を有する流体（流体）濾過用微孔性膜において、AS
TM−316−80の方法によって測定した微孔性膜の孔径の
最大孔径が平均孔径の1.8倍以下であり、ポリスルホン
および／またはポリエーテルスルホンを膜形成ポリマー
とすることを特徴とする流体（液体）濾過用微孔性膜。1. A microporous membrane for fluid filtration, which has a pore size distribution in the film thickness direction and a minimum pore size layer inside the membrane, comprising:
The fluid having a maximum pore diameter of 1.8 times or less of the average pore diameter of the microporous membrane measured by the method of TM-316-80 and using polysulfone and / or polyethersulfone as the membrane-forming polymer (liquid ) A microporous membrane for filtration.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61285997A JP2530133B2 (en) | 1986-12-02 | 1986-12-02 | Microporous membrane |
| DE19873740871 DE3740871A1 (en) | 1986-12-02 | 1987-12-02 | FINE-POROUS MEMBRANE AND METHOD FOR THEIR PRODUCTION |
| US07/127,304 US4840733A (en) | 1986-12-02 | 1987-12-02 | Fine porous membrane and process for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61285997A JP2530133B2 (en) | 1986-12-02 | 1986-12-02 | Microporous membrane |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63141607A JPS63141607A (en) | 1988-06-14 |
| JP2530133B2 true JP2530133B2 (en) | 1996-09-04 |
Family
ID=17698671
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61285997A Expired - Fee Related JP2530133B2 (en) | 1986-12-02 | 1986-12-02 | Microporous membrane |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2530133B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007083145A (en) * | 2005-09-21 | 2007-04-05 | Fujifilm Corp | Cartridge filter of precise filtering membrane |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101523449B1 (en) * | 2010-11-05 | 2015-05-27 | 닛토덴코 가부시키가이샤 | Method for manufacturing sheet-shaped separation membrane |
| TWI658070B (en) | 2013-11-14 | 2019-05-01 | 美商恩特葛瑞斯股份有限公司 | Microporous polyamide-imide membranes |
| CN103831017B (en) * | 2014-02-28 | 2015-11-18 | 成都新柯力化工科技有限公司 | A kind of preparation method of polymer ultrafiltration membrane |
| CN115093703B (en) * | 2022-06-02 | 2024-02-02 | 湖南美柏生物医药有限公司 | Polymer carrier with nano-pore structure for cell culture and preparation method and application thereof |
| CN116272431A (en) * | 2023-04-10 | 2023-06-23 | 赛普(杭州)过滤科技有限公司 | Preparation method of ultrafiltration membrane with controllable thickness of humidity sensing small pore layer and ultrafiltration equipment |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55129109A (en) * | 1979-03-28 | 1980-10-06 | Nitto Electric Ind Co Ltd | Selective permeable membrane |
| JPS5962305A (en) * | 1982-09-30 | 1984-04-09 | Teijin Ltd | Composite membrane for gas separation and its production |
-
1986
- 1986-12-02 JP JP61285997A patent/JP2530133B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007083145A (en) * | 2005-09-21 | 2007-04-05 | Fujifilm Corp | Cartridge filter of precise filtering membrane |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63141607A (en) | 1988-06-14 |
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