JPH0774289B2 - Method for producing hydrophilic tetrafluoroethylene resin porous membrane - Google Patents
Method for producing hydrophilic tetrafluoroethylene resin porous membraneInfo
- Publication number
- JPH0774289B2 JPH0774289B2 JP25463587A JP25463587A JPH0774289B2 JP H0774289 B2 JPH0774289 B2 JP H0774289B2 JP 25463587 A JP25463587 A JP 25463587A JP 25463587 A JP25463587 A JP 25463587A JP H0774289 B2 JPH0774289 B2 JP H0774289B2
- Authority
- JP
- Japan
- Prior art keywords
- tetrafluoroethylene resin
- porous membrane
- membrane
- hydrophilic monomer
- hydrophilic
- 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 - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/30—Polyalkenyl halides
- B01D71/32—Polyalkenyl halides containing fluorine atoms
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treatments Of Macromolecular Shaped Articles (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、四弗化エチレン樹脂多孔質膜の親水化方法に
関するものであり、より詳しくは、放射線照射により四
弗化エチレン樹脂多孔質膜に親水性モノマーをグラフト
重合させて、親水性かつ透水性に優れた四弗化エチレン
樹脂多孔質膜を製造する方法に関する。TECHNICAL FIELD The present invention relates to a method for hydrophilizing a tetrafluoroethylene resin porous membrane, and more specifically, to hydrophilicity of the tetrafluoroethylene resin porous membrane by irradiation with radiation. TECHNICAL FIELD The present invention relates to a method for producing a tetrafluoroethylene resin porous membrane which is excellent in hydrophilicity and water permeability by graft-polymerizing a hydrophilic monomer.
従来の技術 四弗化エチレン樹脂は撥水性であり、その多孔質膜は気
体は容易に透過させるが、液体の水は透過させないとい
う性質をもっているので、その選択透過性を利用して数
々の用途に用いられている。しかしながら、撥水性であ
るため四弗化エチレン樹脂多孔質膜を親水性高分子膜の
応用分野、すなわち濾過膜や透析膜、限外濾過膜、逆浸
透膜などとして水の存在する系における物質分離に応用
するには困難が伴なっている。Conventional technology Tetrafluoride ethylene resin is water repellent, and its porous membrane has the property of easily permeating gas but not liquid water. Therefore, its selective permeability is utilized for various applications. Is used for. However, since it is water-repellent, the tetrafluoroethylene resin porous membrane is used as a hydrophilic polymer membrane application field, that is, as a filtration membrane, dialysis membrane, ultrafiltration membrane, reverse osmosis membrane, etc. It is difficult to apply to.
従来、四弗化エチレン樹脂多孔質膜を親水化する方法と
して、界面活性剤やアルコールによる処理、プラズマや
スパッタリングによる表面処理、あるいは親水性無機物
の充填など種々の方法が試みられているが、親水化が不
十分であったり、親水性が持続しない、あるいは親水性
が不均一であるなどの欠点があった。Conventionally, various methods such as treatment with a surfactant or alcohol, surface treatment with plasma or sputtering, or filling with a hydrophilic inorganic substance have been attempted as methods for hydrophilizing a tetrafluoroethylene resin porous film. However, there are drawbacks such as insufficient polymerization, non-sustainability of hydrophilicity, and nonuniformity of hydrophilicity.
一方、放射線を照射し、生成したラジカルを利用して親
水性モノマーのグラフト反応を進め四弗化エチレン樹脂
を親水化する研究も行なわれている。四弗化エチレン樹
脂はγ線照射により容易にラジカルを生成し、他のモノ
マーが存在すればグラフト重合するが、親水性モノマー
をグラフト重合させると、各種の性能をもった選択性透
過膜が得られる。。On the other hand, studies have also been conducted to irradiate radiation and utilize the generated radicals to promote a graft reaction of a hydrophilic monomer to hydrophilize a tetrafluoroethylene resin. Tetrafluoroethylene resin easily generates radicals by γ-ray irradiation and undergoes graft polymerization in the presence of other monomers, but by graft-polymerizing hydrophilic monomers, selective permeable membranes with various performances are obtained. To be .
例えば、シャピロ（A.Chapiro）らは、四弗化エチレン
樹脂フィルム（非多孔質膜）を、アクリル酸水溶液やメ
タクリル酸水溶液などのモノマー溶液中でγ線照射し、
これらモノマーのグラフト重合を行なっている。（Poly
mer Engineering And Sciene,vol.20,No.3,202,1980）
四弗化エチレン樹脂フィルムにスチレンをグラフト重合
し、これをスルフォン化すると強酸性の膜が得られ、こ
の膜は逆浸透膜としての性能を示す。またアクリル酸や
メタクリル酸をグラフト重合すると、弱酸性の膜が得ら
れるが、これらの膜も逆浸透膜として良好な性質をもっ
ている。４−ビニルピリジンをグラフトすると弱塩基性
の膜が得られる。For example, A.Chapiro et al. Irradiate a tetrafluoroethylene resin film (non-porous film) with γ-rays in a monomer solution such as an acrylic acid aqueous solution or a methacrylic acid aqueous solution,
Graft polymerization of these monomers is carried out. (Poly
mer Engineering And Sciene, vol.20, No.3,202,1980)
Graft-polymerization of styrene onto a tetrafluoroethylene resin film and sulfonation of the film give a strongly acidic membrane, which exhibits the performance as a reverse osmosis membrane. Graft polymerization of acrylic acid or methacrylic acid gives weakly acidic membranes, but these membranes also have good properties as reverse osmosis membranes. Grafting with 4-vinylpyridine gives a weakly basic membrane.
また、林らは、Ｎ−ビニルピロリドンの共存下で四弗化
エチレン樹脂にγ線照射を行ない、そのグラフト重合体
を得ている。（大阪工業技術試験所季報,vol.35,No2,11
7,1984） これらはいずれも、親水性モノマーの共存した状態で照
射を行なっている。Hayashi et al. Obtained a graft polymer by γ-irradiating an ethylene tetrafluoride resin in the coexistence of N-vinylpyrrolidone. (Osaka Industrial Technology Laboratory Quarterly Report, vol.35, No2, 11
7, 1984) All of these are irradiated in the presence of a hydrophilic monomer.
これに対し、セイド（EL−Sayed）らは、四弗化エチレ
ン樹脂フィルム（非多孔質膜）に予めγ線照射を行な
い、しかる後に酢酸ビニルやＮ−ビニルピロリドン、ア
クリル酸、４−ビニルピリジン、メチルメタクリレート
などの各種親水性モノマーの溶液を入れ、グラフト重合
反応を行なっている。（Journal of Applied Polymer S
cience,vol.26,3117,1981） このように、親水性モノマーのグラフト反応による四弗
化エチレン樹脂の親水化に関する従来の技術には、親
水性モノマーを共存させて放射線照射を行なう方法と、
放射線照射を行なった後、親水性モノマーを導入し反
応させる方法とがあった。ところが、これらの従来技術
を四弗化エチレン樹脂多孔質膜に応用しようとした場
合、の方法は、親水性モノマーの単独重合によるホモ
ポリマーの生成により膜中の孔が塞がり、その抽出が困
難であるという問題点を有し、また、の方法は、グラ
フト率が極めて少なく、十分な親水化が期待できないと
いう問題があった。On the other hand, EL-Sayed et al. Pre-irradiate a tetrafluoroethylene resin film (non-porous film) with γ-rays, and then vinyl acetate, N-vinylpyrrolidone, acrylic acid, 4-vinylpyridine. , A solution of various hydrophilic monomers such as methyl methacrylate is put in to carry out a graft polymerization reaction. (Journal of Applied Polymer S
cience, vol.26,3117,1981) As described above, the conventional technique relating to the hydrophilization of the tetrafluoroethylene resin by the graft reaction of the hydrophilic monomer includes a method of irradiating the hydrophilic monomer in the presence of radiation,
After irradiation with radiation, there has been a method in which a hydrophilic monomer is introduced and reacted. However, when attempting to apply these conventional techniques to a tetrafluoroethylene resin porous membrane, the method of is that the pores in the membrane are closed due to the formation of a homopolymer by the homopolymerization of the hydrophilic monomer, and the extraction thereof is difficult. However, the method (1) has a problem that the graft ratio is extremely small and sufficient hydrophilization cannot be expected.
他方、四弗化エチレン樹脂多孔質膜を含む弗素樹脂多孔
性構造物の多孔性空間にポリアクリル酸水溶液を含浸
し、電離放射線によってポリアクリル酸を水に不溶化せ
しめて親水化多孔性複合構造物を得ることも公知であ
る。（特公昭56−2094号公報）しかしながら、この方法
によれば、弗素樹脂多孔性構造物の多孔性空間に水に不
溶化したポリアクリル酸微細多孔性膨潤ゲルが充填され
た構造となるため、四弗化エチレン樹脂多孔質膜の透過
性の低下が大きく、また、ポリアクリル酸が溶出する可
能性があるなどの欠点を有していた。On the other hand, the porous space of a fluororesin porous structure containing a tetrafluoroethylene resin porous membrane is impregnated with an aqueous solution of polyacrylic acid, and the polyacrylic acid is insolubilized in water by ionizing radiation to make it a hydrophilic porous composite structure. It is also known to obtain (Japanese Patent Publication No. 56-2094) However, according to this method, since the porous space of the fluororesin porous structure is filled with water-insolubilized polyacrylic acid fine porous swelling gel, The porous fluoroethylene resin membrane has drawbacks such as a large decrease in permeability and the possibility that polyacrylic acid may be eluted.
以上のように、従来、親水性かつ透水性（透過性）に優
れた四弗化エチレン樹脂多孔質膜を製造することは困難
であった。As described above, conventionally, it has been difficult to produce a porous tetrafluoroethylene resin membrane having excellent hydrophilicity and water permeability (permeability).
発明が解決しようとする問題点 本発明の目的は、前記従来技術の問題点を解決し、親水
性の四弗化エチレン樹脂多孔質膜を製造することにあ
る。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention An object of the present invention is to solve the above problems of the prior art and to produce a hydrophilic porous tetrafluoroethylene resin membrane.
本発明の他の目的は、親水性かつ透水性（透過性）に優
れた四弗化エチレン樹脂多孔質膜を製造することにあ
る。Another object of the present invention is to produce a porous membrane of tetrafluoroethylene resin having excellent hydrophilicity and water permeability (permeability).
本発明者らは、鋭意研究した結果、四弗化エチレン樹脂
多孔質膜に放射線照射を行ない、親水性モノマーをグラ
フト重合させて四弗化エチレン樹脂多孔質膜を親水化す
るにあたり、照射中には該多孔質膜の樹脂表面にのみ親
水性モノマーを存在させ、照射終了後に再び親水性モノ
マーを供給し、照射を行なうことなく、グラフト鎖中に
残存する活性点を利用して重合反応を継続させることに
より親水性かつ透水性（透過性）に優れた四弗化エチレ
ン樹脂多孔質膜の得られることを見出し、この知見に基
づいて本発明を完成するに至った。As a result of intensive studies, the present inventors conducted irradiation of the tetrafluoroethylene resin porous film with radiation, and graft-polymerized a hydrophilic monomer to hydrophilize the tetrafluoroethylene resin porous film during irradiation. Allows the hydrophilic monomer to exist only on the resin surface of the porous membrane, supplies the hydrophilic monomer again after the irradiation is completed, and continues the polymerization reaction by utilizing the active sites remaining in the graft chain without irradiation. It was found that by doing so, a porous membrane of tetrafluoroethylene resin excellent in hydrophilicity and water permeability (permeability) was obtained, and the present invention was completed based on this finding.
問題点を解決するための手段 かくして本発明によれば、四弗化エチレン樹脂多孔質膜
に放射線照射を行ない親水性モノマーをグラフト重合す
ることにより該多孔質膜を親水化する方法において、照
射中に該多孔質膜の樹脂表面にのみ親水性モノマーを存
在させ、照射終了後、該多孔質膜の全面に再び親水性モ
ノマーを供給し、重合反応を継続させることを特徴とす
る親水性四弗化エチレン樹脂多孔質膜の製造方法が提供
される。Means for Solving the Problems Thus, according to the present invention, in a method for hydrophilizing a porous membrane of tetrafluoroethylene resin by graft-polymerizing a hydrophilic monomer by irradiating the porous membrane with radiation, The hydrophilic tetrafluoride is characterized in that the hydrophilic monomer is allowed to exist only on the resin surface of the porous film, and after the irradiation, the hydrophilic monomer is supplied again to the entire surface of the porous film to continue the polymerization reaction. A method for producing a porous ethylene resin porous membrane is provided.
以下、本発明の構成要素について詳述する。Hereinafter, the components of the present invention will be described in detail.
（四弗化エチレン樹脂多孔質膜） 本発明で使用する四弗化エチレン樹脂多孔質膜は、四弗
化エチレン樹脂がマトリックスを形成して内部に空間を
有しており、その空間が膜の表面から裏面まで間通して
いるものを対象としている。このような四弗化エチレン
樹脂多孔質膜は、例えば、四弗化エチレン樹脂のペース
ト押出により得られる未焼結成形体を融点以下の温度で
延伸し、しかる後に焼結する方法（特公昭42−13560号
公報）や四弗化エチレン樹脂繊維粉末を抄紙して多孔質
膜を作る方法など各種の方法により得ることができる。
本発明で用いる四弗化エチレン樹脂多孔質膜は、いずれ
の製造方法によるものであってもよく、また、市販のも
のを使用してもよい。これらの四弗化エチレン樹脂多孔
質膜は、製造条件により微細孔の大きさを0.02〜100μ
ｍ、通常0.1〜10μｍの範囲にかえることができ、ま
た、気孔率も最大95〜96％程度にまですることができる
が、高い気孔率と大きな機械的強度を有するものが好ま
しく使用できる。四弗化エチレン樹脂多孔質膜の形状
は、シートやチューブなど任意のものを対象としてい
る。(Tetrafluoride Ethylene Resin Porous Membrane) The tetrafluoroethylene resin porous membrane used in the present invention has a space in which the tetrafluoroethylene resin forms a matrix and has a space inside. It is intended for those running from the front to the back. Such a tetrafluoroethylene resin porous film is obtained, for example, by a method in which an unsintered molded body obtained by paste extrusion of a tetrafluoroethylene resin is stretched at a temperature not higher than the melting point and then sintered (Japanese Patent Publication No. No. 13560) or a tetrafluoroethylene resin fiber powder is used to make a porous film.
The tetrafluoroethylene resin porous membrane used in the present invention may be produced by any production method, or may be a commercially available one. These tetrafluoroethylene resin porous membranes have micropore sizes of 0.02 to 100μ depending on the manufacturing conditions.
m, usually from 0.1 to 10 μm, and the porosity can be up to about 95 to 96%, but those having high porosity and large mechanical strength can be preferably used. The shape of the tetrafluoroethylene resin porous membrane is intended to be any one such as a sheet or a tube.
（グラフト重合方法） 四弗化エチレン樹脂は、放射線に対する感受性が強く、
容易に分解し、ラジカルを生成するが、ガラス転移点も
低く、生成したラジカルは消滅し易い。したがって、放
射線照射中に四弗化エチレン樹脂多孔質膜の樹脂表面の
周囲に親水性モノマーを存在させると、樹脂に生成した
ラジカルが直ちにモノマーとの反応を行なうので有効で
ある。しかし、多量の親水性モノマーが四弗化エチレン
樹脂多孔膜の周囲に存在するときは、放射線照射条件下
でグラフト反応していない親水性モノマーだけからの親
水性ポリマーが過剰に生成し、そのホモポリマーが多孔
膜の孔を閉塞し、膜の透過性を著しく損う。したがって
親水性モノマーは、四弗化エチレン樹脂多孔質膜の樹脂
表面にのみ存在させることが必要である。この親水性モ
ノマーは四弗化エチレン樹脂にグラフト重合反応し、か
つ活性点を残すことになる。放射線照射後、親水性モノ
マーが追加導入される。このモノマーは、前記親水性モ
ノマーと同じか、または異なっていてもよい。親水性モ
ノマーが追加された後、必要であれば温度を上げて反応
を進める。追加されたモノマーは、すでに樹脂にグラフ
トしたモノマーにより生成したグラフト鎖に残存する活
性点に作用し、引き続き放射線を照射しなくてもグラフ
ト重合反応が継続される結果、グラフト鎖が成長する。
所定のグラフト鎖長あるいはグラフト量に達したところ
で重合反応を終了させる。追加された親水性モノマーに
よる上記グラフト重合反応は、多孔質膜の親水性を向上
させ、かつホモポリマーの過剰な生成が抑制されるため
多孔質膜の透過性を損うことがない。(Graft polymerization method) Tetrafluoroethylene resin has high sensitivity to radiation,
Although it decomposes easily to generate radicals, the glass transition point is also low, and the generated radicals easily disappear. Therefore, when a hydrophilic monomer is allowed to exist around the resin surface of the tetrafluoroethylene resin porous membrane during irradiation with radiation, radicals generated in the resin immediately react with the monomer, which is effective. However, when a large amount of hydrophilic monomer is present around the porous tetrafluoroethylene resin membrane, an excessive amount of hydrophilic polymer is produced only from the hydrophilic monomer that has not undergone the graft reaction under irradiation conditions, and the homopolymer of the hydrophilic polymer is generated. The polymer blocks the pores of the porous membrane, significantly impairing the permeability of the membrane. Therefore, the hydrophilic monomer needs to be present only on the resin surface of the tetrafluoroethylene resin porous membrane. This hydrophilic monomer undergoes a graft polymerization reaction with the tetrafluoroethylene resin and leaves an active site. After irradiation with radiation, a hydrophilic monomer is additionally introduced. This monomer may be the same as or different from the hydrophilic monomer. After the hydrophilic monomer is added, the temperature is raised to proceed the reaction if necessary. The added monomer acts on the active sites remaining in the graft chains formed by the monomers already grafted to the resin, and the graft polymerization reaction continues without irradiation, resulting in the growth of the graft chains.
The polymerization reaction is terminated when a predetermined graft chain length or graft amount is reached. The graft polymerization reaction with the added hydrophilic monomer improves the hydrophilicity of the porous membrane and suppresses the excessive production of the homopolymer, so that the permeability of the porous membrane is not impaired.
照射中に四弗化エチレン樹脂多孔質膜の樹脂表面にのみ
親水性モノマーを存在させるには、例えば、親水性モノ
マー中に四弗化エチレン樹脂多孔質膜を浸漬した後、取
り出し、濾紙で孔中の余剰のモノマー液を吸い取って、
樹脂表面のみにモノマーを存在させる方法、あるいは親
水性モノマーを所定量樹脂表面に塗布する方法など任意
の方法が採用できる。To allow the hydrophilic monomer to exist only on the resin surface of the tetrafluoroethylene resin porous membrane during irradiation, for example, after dipping the tetrafluoroethylene resin porous membrane in the hydrophilic monomer, take it out, and use a filter paper to make a hole. Absorb the excess monomer liquid inside,
Any method such as a method of allowing the monomer to exist only on the resin surface or a method of applying a predetermined amount of the hydrophilic monomer to the resin surface can be adopted.
放射線の照射は、C0を線源としたγ線や電子線により行
なうことができる。四弗化エチレン樹脂は、電離性放射
線の照射により分解し易いが、空気中の酸素を排除した
条件下では分解反応が少なくなるので、樹脂表面にのみ
親水性モノマーを存在させた四弗化エチレン樹脂多孔質
膜は窒素ガスなどの不活性ガスの雰囲気下で照射を行な
うことが好ましい。そのためには、例えば、樹脂表面に
のみ親水性モノマーを存在させた四弗化エチレン樹脂多
孔質膜をプラスチックフィルムで包装し、次いでその中
を窒素ガスで置換した後密封し、その包装状態のままで
放射線を照射すればよい。放射線量は、親水性モノマー
の種類や四弗化エチレン樹脂多孔質膜の大きさなどによ
り適宜定めることができるが、通常、0.1〜12Mradの範
囲が四弗化エチレン樹脂多孔質膜を劣化させないために
好ましい。The irradiation of radiation can be carried out by γ-rays or electron beams having C 0 as a radiation source. The tetrafluoroethylene resin is easily decomposed by irradiation with ionizing radiation, but the decomposition reaction is reduced under the condition that oxygen in the air is excluded. Therefore, the tetrafluoroethylene resin containing a hydrophilic monomer only on the resin surface is used. It is preferable that the porous resin film be irradiated in an atmosphere of an inert gas such as nitrogen gas. For that purpose, for example, a tetrafluoroethylene resin porous membrane in which a hydrophilic monomer is present only on the resin surface is packaged with a plastic film, then the inside is replaced with nitrogen gas and then sealed, and the packaged state is maintained. Radiation may be applied. The radiation dose can be appropriately determined depending on the type of hydrophilic monomer and the size of the tetrafluoroethylene resin porous film, but normally, the range of 0.1 to 12 Mrad does not deteriorate the tetrafluoroethylene resin porous film. Is preferred.
照射終了後、四弗化エチレン樹脂多孔質膜の全面に再び
親水性モノマーを供給するには、四弗化エチレン樹脂多
孔質膜を親水性モノマーで浸漬すればよい。例えば、プ
ラスチックフィルム中に密封して照射を行なった場合に
は、照射終了後、包装中に親水性モノマーを満たすこと
により、多孔質膜の全面に親水性モノマーを供給するこ
とができる。もちろんプラスチックフィルムの包装以外
にも適当な容器を用いてもよい。前記したとおり、追加
した親水性モノマーは、照射を止めてもグラフト鎖中に
残存する活性点により重合反応が継続される。この段階
での反応の継続は、室温でもよいが、通常、30〜120
℃、好ましくは40〜80℃の温度範囲で、0.5〜48時間、
好ましくは１〜12時間反応させる。After the irradiation, in order to supply the hydrophilic monomer again to the entire surface of the tetrafluoroethylene resin porous membrane, the tetrafluoroethylene resin porous membrane may be immersed in the hydrophilic monomer. For example, when irradiation is performed by sealing in a plastic film, the hydrophilic monomer can be supplied to the entire surface of the porous membrane by filling the hydrophilic monomer in the package after the irradiation is completed. Of course, an appropriate container other than the plastic film packaging may be used. As described above, the added hydrophilic monomer continues the polymerization reaction due to the active sites remaining in the graft chain even when the irradiation is stopped. The reaction at this stage may be continued at room temperature, but usually 30-120.
℃, preferably in the temperature range of 40 ~ 80 ℃, 0.5 ~ 48 hours,
The reaction is preferably carried out for 1 to 12 hours.
反応終了後は、親水性モノマーをグラフト重合した四弗
化エチレン樹脂多孔質膜を取り出して、グラフト重合せ
ずに単独に生成した親水性ポリマーや未反応モノマーな
どを水や温水などを用いて洗浄することにより十分に抽
出・除去する。After completion of the reaction, take out the tetrafluoroethylene resin porous membrane graft-polymerized with a hydrophilic monomer, and wash the hydrophilic polymer and unreacted monomer produced independently without graft polymerization with water or warm water. By doing so, it is sufficiently extracted and removed.
（親水性モノマー） 本発明において用いる親水性モノマーとしては、例え
ば、アクリル酸、メタクリル酸、Ｎ−ビニルピロリド
ン、Ｎ−ビニルピリジン、メチルメタクリレート、アク
リルアミドなどが挙げられる。これらのモノマーは、単
独で、あるいは数種類組み合わせて使用する。また、放
射線照射の際に四弗化エチレン樹脂多孔質膜の表面にの
み存在させたモノマーと照射後に追加されるモノマーと
は同一であっても、異なるものであってもかまわない。(Hydrophilic Monomer) Examples of the hydrophilic monomer used in the present invention include acrylic acid, methacrylic acid, N-vinylpyrrolidone, N-vinylpyridine, methyl methacrylate, and acrylamide. These monomers are used alone or in combination of several kinds. Further, the monomer that is present only on the surface of the tetrafluoroethylene resin porous film at the time of irradiation with the radiation and the monomer added after the irradiation may be the same or different.
（親水性四弗化エチレン樹脂多孔質膜） 本発明の方法により得られた親水性四弗化エチレン樹脂
多孔質膜は、該多孔質膜の表面にのみ親水性モノマーを
存在させて放射線照射によるグラフト重合を行なってい
るため、孔中に親水性モノマーの重合体が生成して膜の
透過性が損なわれることがない。しかも、照射後に親水
性モノマーを該多孔質膜の全面に供給してグラフト鎖に
残存する活性点を利用してグラフト重合反応を継続させ
ているため、グラフト量を調整することができ、親水性
が高度に達成されたものとなる。(Hydrophilic tetrafluoroethylene resin porous film) The hydrophilic tetrafluoroethylene resin porous film obtained by the method of the present invention is produced by irradiating radiation with a hydrophilic monomer present only on the surface of the porous film. Since the graft polymerization is performed, a polymer of a hydrophilic monomer is not generated in the pores and the permeability of the membrane is not impaired. Moreover, since the hydrophilic monomer is supplied to the entire surface of the porous film after irradiation and the graft polymerization reaction is continued by utilizing the active sites remaining in the graft chains, the graft amount can be adjusted and the hydrophilic property can be improved. Will be highly achieved.
本発明の親水性四弗化エチレン樹脂多孔質膜が親水性お
よび透過性に優れていることは、親水性モノマーのグラ
フト率が適度に高く、かつ透水量が大きいことから明ら
かである。また、親水性モノマーをグラフト重合して親
水化を行なっているため、本発明の多孔質膜を使用中に
グラフトした親水性ポリマー部分が溶出することがな
い。It is clear that the hydrophilic tetrafluoroethylene resin porous membrane of the present invention is excellent in hydrophilicity and permeability because the graft ratio of the hydrophilic monomer is reasonably high and the water permeability is large. Further, since the hydrophilic monomer is graft-polymerized to make it hydrophilic, the hydrophilic polymer portion grafted during use of the porous membrane of the present invention does not elute.
（用途） 本発明の親水性四弗化エチレン樹脂多孔質膜は、その親
水性と透過性を活用して、濾過膜や透析膜、限外濾過
膜、逆浸透膜などとして水の存在する系における物質分
離に応用することができ、特に耐熱性、耐薬品性、機械
的強度に優れていることから医療やバイオ技術関連の分
離膜として好適である。(Use) The hydrophilic tetrafluoroethylene resin porous membrane of the present invention is a system in which water is present as a filtration membrane, dialysis membrane, ultrafiltration membrane, reverse osmosis membrane, etc. by utilizing its hydrophilicity and permeability. It can be applied to the separation of substances in, and is particularly suitable as a separation membrane for medical treatment and biotechnology because it has excellent heat resistance, chemical resistance, and mechanical strength.
実施例 以下、本発明を実施例および比較例を挙げて具体的に説
明するが、本発明はこれらの実施例のみに限定されるも
のではない。EXAMPLES Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
実施例 平均孔径0.45μｍの四弗化エチレン樹脂多孔質膜（住友
電気工業社製、フロロポアFP−045）をメタクリル酸中
に完全に含浸した後取り出し、２枚の濾紙にはさんで軽
く押さえ、孔中の余剰のモノマー液を除いた。この表面
のみにメタクリル酸モノマーが存在する多孔質膜を、厚
さ25μｍのポリエチレンフィルムで包装し、その中を窒
素ガスで封じた。Example A tetrafluoroethylene resin porous membrane having an average pore size of 0.45 μm (Fluoropore FP-045 manufactured by Sumitomo Electric Industries, Ltd.) was completely impregnated in methacrylic acid, then taken out, and lightly sandwiched between two filter papers, Excess monomer solution in the holes was removed. The porous film having methacrylic acid monomer present only on this surface was wrapped with a polyethylene film having a thickness of 25 μm, and the inside was sealed with nitrogen gas.
これに加速電圧400kvの電子線を2Mrad室温で照射した
後、包装の中にメタクリル酸を満たして多孔質膜の全面
にメタクリル酸を供給し、60℃で８時間反応させた。次
いで包装の中から多孔質膜をとり出し、流水中で２時
間、さらに80℃の温水中でよく撹拌しながら２時間にわ
たって未反応モノマーとグラフト反応していない親水性
ポリマーの抽出を行なった。その後、60℃で一昼夜真空
乾燥した。得られた多孔質膜の重量増加を求めたところ
4.2重量％の増加率であり、該多孔質膜を水に浮かべた
ところ、ただちに水が膜全体に浸透した。この多孔質膜
の透水量を測定したところ、32ml/min・cm2・atmであっ
た。After irradiating this with an electron beam with an accelerating voltage of 400 kv at 2 Mrad room temperature, the package was filled with methacrylic acid to supply methacrylic acid to the entire surface of the porous membrane and reacted at 60 ° C. for 8 hours. Then, the porous membrane was taken out from the package, and the hydrophilic polymer which had not been graft-reacted with the unreacted monomer was extracted for 2 hours in running water and further for 2 hours while stirring well in warm water at 80 ° C. Then, it was vacuum dried at 60 ° C. for a whole day and night. When the weight increase of the obtained porous membrane was determined
The rate of increase was 4.2% by weight, and when the porous membrane was floated on water, water immediately penetrated the entire membrane. The water permeability of this porous membrane was measured and found to be 32 ml / min · cm 2 · atm.
比較例1. 実施例で用いたのと同じ多孔質膜をエチレン−酢酸ビニ
ル共重合体ケン化物フィルムで包み、その中にメタクリ
ル酸を多孔質膜容積の４倍量入れ、その中を窒素ガスで
置換した後密封した。この後実施例と同じ条件で電子線
を照射し、次いで60℃で８時間反応させた。多孔質膜中
には白いポリマーが析出した。これを実施例１と同じ条
件で抽出乾燥し、重量増加を求めたところ、8.4重量％
の増加率であり、その透水量を測定したところ、3ml/mi
n・cm2・atmと極めて低い値しか得られなかった。Comparative Example 1. The same porous membrane as used in the examples was wrapped with a saponified film of ethylene-vinyl acetate copolymer, and methacrylic acid was placed therein in an amount of 4 times the volume of the porous membrane, and nitrogen gas was introduced therein. It was replaced with and sealed. After this, electron beam irradiation was performed under the same conditions as in the example, and then the reaction was carried out at 60 ° C for 8 hours. White polymer was deposited in the porous film. This was extracted and dried under the same conditions as in Example 1, and the weight increase was determined to be 8.4% by weight.
It is the rate of increase of water, and when its water permeability was measured, it was 3 ml / mi.
Only a very low value of n · cm 2 · atm was obtained.
比較例２ 実施例で用いたのと同じ多孔質膜を用い、同様にメタク
リル酸中に完全に含浸した後取り出し、２枚の濾紙には
さんで軽く押さえ、孔中の余剰のモノマー液を除いた。
この多孔質膜をエチレン−酢酸ビニル共重合体ケン化物
フィルムで包み、その中を窒素ガスで置換した。Comparative Example 2 Using the same porous membrane as that used in the Example, similarly completely impregnated in methacrylic acid and then taken out, lightly sandwiched between two filter papers to remove excess monomer liquid in the pores. It was
This porous membrane was wrapped with a saponified film of ethylene-vinyl acetate copolymer, and the inside was replaced with nitrogen gas.
このあと実施例と同じ条件で電子線を照射してグラフト
反応を行ない、その後メタクリル酸を追加供給すること
なく多孔質膜を取り出し、抽出操作を行なった。グラフ
ト率は、0.7重量％と低く、水はほとんど膜に浸透しな
かった。After that, the graft reaction was carried out by irradiating an electron beam under the same conditions as in Example, and then the porous membrane was taken out without additional supply of methacrylic acid, and an extraction operation was performed. The graft ratio was as low as 0.7% by weight, and water hardly penetrated the membrane.
発明の効果 本発明は、以上説明したように、放射線照射により四弗
化エチレン樹脂多孔質膜に親水性モノマーをグラフトす
るにあたり、照射時に樹脂表面にのみ親水性モノマーを
存在させ、かつ照射後にも親水性モノマーを追加導入し
て反応を継続させることにより、親水性かつ透水性に優
れた親水性四弗化エチレン樹脂多孔質膜を製造する方法
を提供する。本発明により得られる親水性四弗化エチレ
ン樹脂多孔質膜は、耐熱性、耐薬品性、機械的強度に優
れることからとりわけ医療、バイオ関連の分離膜などと
して広範な分野で好適に利用することができる。Effects of the Invention As described above, in the present invention, when a hydrophilic monomer is grafted onto a tetrafluoroethylene resin porous membrane by irradiation with radiation, the hydrophilic monomer is allowed to exist only on the resin surface during irradiation, and even after irradiation. Provided is a method for producing a hydrophilic tetrafluoroethylene resin porous membrane which is excellent in hydrophilicity and water permeability by additionally introducing a hydrophilic monomer and continuing the reaction. The hydrophilic tetrafluoroethylene resin porous membrane obtained by the present invention is excellent in heat resistance, chemical resistance, and mechanical strength, and therefore, it can be suitably used in a wide range of fields as separation membranes related to medical treatment and biotechnology. You can
Claims (1)
を行ない親水性モノマーをグラフト重合することにより
該多孔質膜を親水化する方法において、照射中に該多孔
質膜の樹脂表面にのみ親水性モノマーを存在させ、照射
終了後、該多孔質膜の全面に再び親水性モノマーを供給
し、重合反応を継続させることを特徴とする親水性四弗
化エチレン樹脂多孔質膜の製造方法。1. A method of hydrophilizing a porous tetrafluoroethylene resin membrane by irradiating the porous membrane with radiation to perform graft polymerization of a hydrophilic monomer, wherein only the resin surface of the porous membrane is exposed during irradiation. A method for producing a hydrophilic tetrafluoroethylene resin porous membrane, comprising the step of allowing a hydrophilic monomer to be present and, after irradiation, supplying the hydrophilic monomer again to the entire surface of the porous membrane to continue the polymerization reaction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25463587A JPH0774289B2 (en) | 1987-10-12 | 1987-10-12 | Method for producing hydrophilic tetrafluoroethylene resin porous membrane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25463587A JPH0774289B2 (en) | 1987-10-12 | 1987-10-12 | Method for producing hydrophilic tetrafluoroethylene resin porous membrane |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0198640A JPH0198640A (en) | 1989-04-17 |
| JPH0774289B2 true JPH0774289B2 (en) | 1995-08-09 |
Family
ID=17267757
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25463587A Expired - Lifetime JPH0774289B2 (en) | 1987-10-12 | 1987-10-12 | Method for producing hydrophilic tetrafluoroethylene resin porous membrane |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0774289B2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5282965A (en) * | 1990-11-29 | 1994-02-01 | Nitto Denko Corporation | Membrane filter for liquids and filtering device using the same |
| CA2138056A1 (en) * | 1994-05-20 | 1995-11-21 | Peter John Degen | Hydrophilic ptfe membrane |
| KR100763212B1 (en) * | 1998-12-30 | 2007-10-08 | 에디컨인코포레이티드 | Sterile Packaging For Flexible Endoscopes |
| JP4427291B2 (en) | 2003-09-03 | 2010-03-03 | 東亞合成株式会社 | Continuous production method of functional membrane |
| ITMI20050474A1 (en) * | 2005-03-22 | 2006-09-23 | Solvay Solexis Spa | POWDERS OR MANUFACTURED PRODUCTS WITH A SUPERFICIAL HYDROPHILICITY |
| JP2016013544A (en) * | 2014-06-13 | 2016-01-28 | ダイキン工業株式会社 | Porous membrane |
| CN113004569B (en) * | 2021-02-09 | 2023-03-21 | 深圳华源再生医学有限公司 | Method for modifying porous membrane, modified porous membrane and application thereof |
-
1987
- 1987-10-12 JP JP25463587A patent/JPH0774289B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0198640A (en) | 1989-04-17 |
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