JP2004275845A - Filter medium for organic solvent or organic detergent and its filter - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、有機溶剤又は有機洗浄剤用フィルタ濾材と該濾材を用いたフィルタに関する。さらに詳しくは、有機溶剤又は有機洗浄剤を循環再利用する工程において適用されるのに好適なフィルタ濾材と該濾材を用いたフィルタの改良に関する。
【０００２】
【従来の技術】
従来、例えば半導体工程のフォトレジスト剤の濾過材としては、耐溶剤性、耐熱性の点から、ポリテトラフルオロエチレン樹脂からなる微多孔質膜（ＰＴＦＥ膜）が使用されている。ＰＴＦＥ膜は、化学的に安定である反面、あらゆる液体との濡れ性が悪いため、濾過圧力が高くなり、膜自体に高い強度が必要とされる。また、ＰＴＦＥ膜はハロゲンであるフッ素を材料中に含有しているため、焼却時に有毒ガスが発生し、容易に廃棄できないという問題も有している。さらに、原料樹脂自体が高価な上、製造工程も、押出し・圧延・延伸の煩雑な工程を経て製造されるため、製品単価が極めて高価になるという問題がある。
このようなＰＴＦＥ膜の問題を解決するため、耐溶剤性に優れたポリエチレン樹脂と可塑剤の混合物を溶融押出ししてシート化し、可塑剤を抽出することによって製造されるポリエチレン微多孔質膜が提案されている（例えば、特許文献１）。
【０００３】
【特許文献１】
特開２０００−３１７２８０号（請求項１、第２頁）
【０００４】
【発明が解決しようとする課題】
しかしながら、前記ポリエチレン微多孔質膜は、上記ＰＴＦＥ膜の問題を解決できる点で有利であるものの、耐熱性ではＰＴＦＥ膜より大きく劣るものであった。
そこで、本発明は、上記従来のＰＴＦＥ膜の問題を解決することのできるポリエチレン微多孔質膜において、耐熱性の向上を図り、ＰＴＦＥ膜の代替を図ることを目的とする。
【０００５】
【課題を解決するための手段】
本発明の有機溶剤又は有機洗浄剤用フィルタ濾材は、前記目的を達成するべく、請求項１に記載の通り、超高分子量ポリエチレン樹脂と、耐熱性を有する微細フィラーとを含有してなり、平均孔径０．０１〜５μｍの貫通孔を有し、膜厚が２５〜３００μｍである微多孔質膜よりなることを特徴とする。
また、請求項２記載の有機溶剤又は有機洗浄剤用フィルタ濾材は、請求項１記載のフィルタ濾材において、前記微細フィラーが、平均二次粒子径２０μｍ以下の粉体又は平均繊維長２０μｍ以下の短繊維であることを特徴とする。
また、請求項３記載の有機溶剤又は有機洗浄剤用フィルタ濾材は、請求項１又は２記載のフィルタ濾材において、前記微細フィラーが、有機溶剤に安定な無機酸化物からなることを特徴とする。
また、請求項４記載の有機溶剤又は有機洗浄剤用フィルタ濾材は、請求項１乃至３の何れかに記載のフィルタ濾材において、前記微細フィラーが、吸着能を有することを特徴とする。
また、請求項５記載の有機溶剤又は有機洗浄剤用フィルタ濾材は、請求項４記載のフィルタ濾材において、前記吸着能を有する微細フィラーが、ゼオライト、チタン酸カリウム、酸化チタン、セピオライト、活性炭から選ばれた１種又は２種以上であることを特徴とする。
本発明の有機溶剤又は有機洗浄剤用フィルタは、前記目的を達成するべく、請求項６に記載の通り、請求項１乃至５の何れかに記載のフィルタ濾材を用いてなることを特徴とする。
【０００６】
【発明の実施の形態】
本発明の有機溶剤又は有機洗浄剤用フィルタ濾材は、超高分子量ポリエチレン樹脂と、耐熱性を有する微細フィラーとを含有してなり、平均孔径０．０１〜５μｍの貫通孔を有し、膜厚が２５〜３００μｍである微多孔質膜よりなるものである。
つまり、前記フィルタ濾材を構成する微多孔質膜は、耐熱性を有する微細フィラーを含有しているため、熱雰囲気中での微多孔質膜の寸法安定性が向上するとともに、前記微細フィラーが骨材として機能し、さらに、熱流動性の極めて低い超高分子量ポリエチレン樹脂が、骨材として機能する前記微細フィラーを連結して支持するため、加熱による収縮や微細孔の閉塞を低減することができ、結果として、前記フィルタ濾材の耐熱性が向上する。
【０００７】
前記フィルタ濾材に用いる超高分子量ポリエチレン樹脂は、極限粘度法から換算した重量平均分子量１００万以上の超高分子量ポリエチレン樹脂が好ましく、重量平均分子量２００万以上の超高分子量ポリエチレン樹脂がより好ましい。尚、このような超高分子量ポリエチレン樹脂は、熱流動性が極めて低いため、加工性が悪く押出生産性を低下させる原因となるが、本発明では、後述するように、可塑剤を同時に配合することにより、押出しを可能とするとともに押出生産性の向上を図っている。また、このような超高分子量ポリエチレン樹脂よりも熱流動性が良好なポリエチレン樹脂材料として、同じく極限粘度法から換算した重量平均分子量が２０〜９０万の高分子量ポリエチレン樹脂を、微多孔質膜の機械的強度の大幅な低下を招かない範囲内で併用するようにすれば、更なる押出生産性の向上が図れる。
【０００８】
前記微細フィラーとして用いる粉体は、膜内における均一分散性と膜の無欠陥化の観点から、前記フィルタ濾材の膜厚以下である平均二次粒子径が２０μｍ以下のものを用いることが好ましい。具体的には、酸化ケイ素、酸化アルミニウム、酸化チタン、酸化ジルコニウム等の無機酸化物系や、活性炭粒子等の粉体を用いることができる。尚、無機酸化物粒子を合成する際に、平均二次粒子径２０μｍ以下が得られない場合は、分級によって２０μｍ以下のものを得るようにする。
【０００９】
前記微細フィラーとして用いる短繊維は、粉体の場合と同様に、膜内における均一分散性と膜の無欠陥化の観点から、前記フィルタ濾材の膜厚以下である平均繊維長２０μｍ以下のものを用いることが好ましい。具体的には、チタン酸カリウムウィスカー、セピオライト繊維等の無機酸化物系の短繊維を用いることができる。
尚、前記微細フィラーとしては、上記のような粉体又は短繊維のいずれか一方を用いてもよいし、双方を用いてもよい。尚、上記したように、微細フィラーを微多孔質膜の骨格として機能させるという観点からは、粉体状物よりも繊維状物の方が有利であるため、短繊維の割合を多くした方が好ましいと言えるが、微多孔質膜作製過程での微細フィラーのより均一な分散という観点からは、繊維状物よりも粉体状物の方が有利であるため、粉体の割合を多くした方が好ましいと言える。本発明においては、微細フィラーの均一分散性は絶対に軽視できない要件であるので、結果として、微細フィラーとしては、上記粉体の単独使用か、もしくは上記粉体に上記短繊維を均一分散性を損なわない範囲内で併用する形が好ましいと言える。つまり、均一分散性をより重視する必要がある場合には、上記粉体単独もしくはそれに近い併用が好ましく、骨格形成すなわち耐熱性をより重視する必要がある場合には、上記粉体に適当量の上記短繊維を併用するようにするのが好ましい。
【００１０】
前記微細フィラーとしては、耐溶剤性や耐熱性の観点から、無機酸化物系の材料を用いることが好ましいが、濾過する有機溶剤に対する耐性があり、押出成形温度で熱変形のない材料であれば、有機材料を用いても差し支えない。
また、前記微細フィラーとして、吸着能を有するものを用いることも可能である。吸着能を有する微細フィラーをフィルタ濾材に用いることにより、微細粒子状不純物も効率よく除去することができるようになる。このような吸着能を有する微細フィラーとしては、ゼオライト、チタン酸カリウム、酸化チタン、セピオライト、活性炭が挙げられる。
【００１１】
次に、本発明の有機溶剤又は有機洗浄剤用フィルタ濾材の製造方法の一例について説明する。
（１）極限粘度法から換算した重量平均分子量２０〜９０万の高分子量ポリエチレン樹脂０〜４０質量％と、同じく極限粘度法から換算した重量平均分子量１００〜６００万の超高分子量ポリエチレン樹脂２０〜４０質量％と、耐熱性を有する微細フィラー２０〜８０質量％とを混合し、さらに適量の可塑剤を加えて混合する。
（２）該混合物を二軸押出成形機を用いて加熱溶融・混練しながらシート状物を成形する。得られたシート状物は、延伸、圧延等の二次加工によって膜厚を２５〜３００μｍに調整することができる。
（３）該シート中の可塑剤を適当な抽出剤を用いて抽出除去し、乾燥することにより、平均孔径０．０１〜５μｍの貫通孔を有する微多孔質膜よりなる本発明のフィルタ濾材が得られる。
【００１２】
前記可塑剤としては、飽和炭化水素からなる工業用潤滑油に代表される鉱物オイル、あるいは、フタル酸ジ−２−エチルヘキシルに代表される樹脂用可塑剤が使用できる。
また、前記可塑剤を抽出除去するための抽出剤としては、ヘキサン、ヘプタン、オクタン、ノナン、デカン等の飽和炭化水素系の有機溶剤や、トリクロロエチレン、テトラクロロエチレン等のハロゲン化炭化水素系の有機溶剤が使用できる。
このように、前記可塑剤は微孔形成剤としての役割をも果たすため、該可塑剤を多量に配合することにより、フィルタ濾材の空隙率を高く設定することができ、濾過流量を増大させることができるとともに、捕集する不純物の保持容量を増大させることができる等、前記フィルタ濾材の濾過性能を向上させることができる。
【００１３】
本発明のフィルタ濾材は、平均孔径が０．０１〜５μｍの微細孔を有するため、微細粒子状不純物をも、除去可能になるとともに、孔径分布が揃っているため、濾過精度の向上を図ることができる。
また、本発明のフィルタ濾材は、膜厚を２５〜３００μｍの範囲で適宜設定可能なため、常に、濾過対象に適した膜厚のフィルタ濾材を得るようにすることにより、濾過精度の向上を図ることができる。
【００１４】
【実施例】
次に、本発明の実施例について比較例と共に詳細に説明するが、本発明はこの例に限定されるものではない。
【００１５】
（実施例１）
極限粘度法から換算した重量平均分子量３０万の高分子量ポリエチレン樹脂１０質量％と、同じく極限粘度法から換算した重量平均分子量２００万の超高分子量ポリエチレン樹脂２５質量％と、湿式法による平均二次粒子径１０μｍの酸化ケイ素微粉体６５質量％とからなる混合物に、該混合物に対して２倍質量の鉱物オイルを加えてレーディゲミキサを用いて混合した。この混合物を二軸押出成形機を用いて加熱溶融・混練しながらシート状に押出成形し、厚さ２００μｍのシートを得た。次いで、該シート中の鉱物オイルを、トリクロロエチレンを用いて抽出除去し、さらに箱形乾燥機を用いて１００℃で乾燥して、平均孔径０．０５μｍ、空隙率７０体積％の微多孔質膜よりなるフィルタ濾材を得た。
【００１６】
（実施例２）
極限粘度法から換算した重量平均分子量３０万の高分子量ポリエチレン樹脂１０質量％と、同じく極限粘度法から換算した重量平均分子量２００万の超高分子量ポリエチレン樹脂２５質量％と、湿式法による平均二次粒子径１０μｍの酸化ケイ素微粉体４０質量％と、チタン酸カリウムウィスカー２５質量％とからなる混合物に、該混合物に対して２倍質量の鉱物オイルを加えてレーディゲミキサを用いて混合した。この混合物を二軸押出成形機を用いて加熱溶融・混練しながらシート状に押出成形し、厚さ２００μｍのシートを得た。次いで、該シート中の鉱物オイルを、トリクロロエチレンを用いて抽出除去し、さらに箱形乾燥機を用いて１００℃で乾燥して、平均孔径０．０７μｍ、空隙率７０体積％の微多孔質膜よりなるフィルタ濾材を得た。
【００１７】
（実施例３）
極限粘度法から換算した重量平均分子量３０万の高分子量ポリエチレン樹脂１０質量％と、同じく極限粘度法から換算した重量平均分子量２００万の超高分子量ポリエチレン樹脂２５質量％と、湿式法による平均二次粒子径１０μｍの酸化ケイ素微粉体６５質量％とからなる混合物に、該混合物に対して２倍質量の鉱物オイルを加えてレーディゲミキサを用いて混合した。この混合物を二軸押出成形機を用いて加熱溶融・混練しながらシート状に押出成形し、厚さ１００μｍのシートを得た。次いで、該シートを一軸延伸装置により４倍延伸して、厚さ２５μｍのシートを得た。次いで、該シート中の鉱物オイルを、トリクロロエチレンを用いて抽出除去し、さらに箱形乾燥機を用いて１００℃で乾燥して、平均孔径０．０６μｍ、空隙率８５体積％の微多孔質膜よりなるフィルタ濾材を得た。
【００１８】
（比較例１）
極限粘度法から換算した重量平均分子量３０万の高分子量ポリエチレン樹脂１００質量％に、２倍質量の鉱物オイルを加えてレーディゲミキサを用いて混合した。この混合物を二軸押出成形機を用いて加熱溶融・混練しながらシート状に押出成形し、厚さ２００μｍのシートを得た。次いで、該シート中の鉱物オイルを、トリクロロエチレンを用いて抽出除去し、さらに箱形乾燥機を用いて１００℃で乾燥して、平均孔径０．０５μｍ、空隙率６０体積％の微多孔質膜よりなるフィルタ濾材を得た。
【００１９】
（比較例２）
極限粘度法から換算した重量平均分子量３０万の高分子量ポリエチレン樹脂８０質量％と、同じく極限粘度法から換算した重量平均分子量２００万の超高分子量ポリエチレン樹脂２０質量％とからなる混合物に、該混合物の２倍質量の鉱物オイルを加えてレーディゲミキサを用いて混合した。この混合物を二軸押出成形機を用いて加熱溶融・混練しながらシート状に押出成形し、厚さ２００μｍのシートを得た。次いで、該シート中の鉱物オイルを、トリクロロエチレンを用いて抽出除去し、さらに箱形乾燥機を用いて１００℃で乾燥して、平均孔径０．０５μｍ、空隙率６０体積％の微多孔質膜よりなるフィルタ濾材を得た。
【００２０】
（比較例３）
極限粘度法から換算した重量平均分子量３０万の高分子量ポリエチレン樹脂３５質量％と、湿式法による平均二次粒子径１０μｍの酸化ケイ素微粉体６５質量％とからなる混合物に、該混合物に対して２倍質量の鉱物オイルを加えてレーディゲミキサを用いて混合した。この混合物を二軸押出成形機を用いて加熱溶融・混練しながらシート状に押出成形し、厚さ２００μｍのシートを得た。次いで、該シート中の鉱物オイルを、トリクロロエチレンを用いて抽出除去し、さらに箱形乾燥機を用いて１００℃で乾燥して、平均孔径０．０５μｍ、空隙率６０体積％の微多孔質膜よりなるフィルタ濾材を得た。
【００２１】
次に、このようにして得られた実施例１乃至３、比較例１乃至３の各フィルタ濾材の厚さ、空隙率、最大孔径、平均孔径、熱収縮率を測定した。その結果を表１に示す。
【００２２】
【表１】
表１から以下のようなことが分かった。
（１）比較例１乃至３のフィルタ濾材では、約２０〜３０％の熱収縮が起きているのに対して、実施例１乃至３のフィルタ濾材では、約１〜５％の熱収縮しか起きていない。よって、実施例１乃至３のフィルタ濾材は、比較例１乃至３のフィルタ濾材と比べて、熱収縮率が少ないことから、耐熱性が向上している。特に、微細フィラーとして、粉体形状の酸化ケイ素微粉体と共に繊維形状のチタン酸カリウムウィスカーを併用した実施例２のフィルタ濾材では、微多孔質膜の骨格形成が良好なため、熱収縮率が特に少なく、優れた耐熱性を有している。
（２）実施例１乃至３のフィルタ濾材は、比較例１乃至３のフィルタ濾材と比べて、空隙率が約１６〜４２％大きくなっている。よって、実施例１乃至３のフィルタ濾材は、比較例１乃至３のフィルタ濾材と比べて、捕集される不純物を保持するための空隙率が大きくなり、濾過流量を増大させることができるため、濾過性能を向上させることができる。
（３）実施例３のフィルタ濾材のように、高分子量ポリエチレン樹脂と、超高分子量ポリエチレン樹脂と、微細フィラーとを含有したフィルタ濾材を延伸処理することにより、任意の膜厚のフィルタ濾材を得ることができる。
【００２４】
【発明の効果】
本発明の如く、超高分子量ポリエチレン樹脂と、耐熱性に優れた微細フィラーとを混合することで、耐溶剤性に優れた従来のポリエチレン微多孔質膜の問題点である耐熱性を大幅に改善した有機溶剤又は有機洗浄剤用フィルタ濾材を提供することができるので、耐溶剤性や耐熱性が求められる半導体工程のフォトレジスト剤の濾過材として従来用いられていたＰＴＦＥ膜の持つ欠点（濾液との濡れ性が悪い，廃棄が容易でない，製品単価が非常に高い）を解消して、従来のＰＴＦＥ膜に代わる安価な代替材として非常に価値が高い。
また、本発明のフィルタ濾材は、微細フィラーを多量に含んでいるため、通常のポリエチレン樹脂単独からなる微多孔質膜に比べ空隙率が大きくなり、比表面積が大幅に増加するため、界面活性剤等の二次加工薬剤を練り込み又は後付けした場合、二次加工薬剤の担持面積が増加するので、濡れ性等の効果が永続的に発揮されるというメリットがある。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a filter medium for an organic solvent or an organic cleaning agent and a filter using the filter medium. More specifically, the present invention relates to a filter medium suitable for being applied in a step of circulating and recycling an organic solvent or an organic cleaning agent, and an improvement of a filter using the filter medium.
[0002]
[Prior art]
Conventionally, a microporous film (PTFE film) made of polytetrafluoroethylene resin has been used as a filter material for a photoresist agent in a semiconductor process, for example, in view of solvent resistance and heat resistance. The PTFE membrane is chemically stable, but has poor wettability with all liquids, so that the filtration pressure increases and the membrane itself needs to have high strength. Further, since the PTFE film contains fluorine, which is a halogen, in the material, a toxic gas is generated at the time of incineration, and there is a problem that it cannot be easily disposed. Furthermore, the raw material resin itself is expensive, and the manufacturing process is also manufactured through complicated steps of extrusion, rolling and stretching, so that there is a problem that the product unit price becomes extremely expensive.
In order to solve such a problem of the PTFE membrane, a microporous polyethylene membrane produced by melt-extruding a mixture of a polyethylene resin and a plasticizer having excellent solvent resistance into a sheet and extracting the plasticizer is proposed. (For example, Patent Document 1).
[0003]
[Patent Document 1]
JP-A-2000-317280 (Claim 1, page 2)
[0004]
[Problems to be solved by the invention]
However, the polyethylene microporous membrane is advantageous in that the problem of the PTFE membrane can be solved, but is much inferior to the PTFE membrane in heat resistance.
Therefore, an object of the present invention is to improve the heat resistance of a microporous polyethylene membrane that can solve the above-mentioned problems of the conventional PTFE membrane, and to replace the PTFE membrane.
[0005]
[Means for Solving the Problems]
The organic solvent or the filter medium for an organic cleaning agent of the present invention contains an ultrahigh molecular weight polyethylene resin and a fine filler having heat resistance, as described in claim 1, in order to achieve the above-mentioned object. It is characterized by comprising a microporous membrane having a through hole with a pore diameter of 0.01 to 5 μm and a thickness of 25 to 300 μm.
The filter medium for an organic solvent or an organic cleaning agent according to claim 2 is the filter medium according to claim 1, wherein the fine filler is a powder having an average secondary particle diameter of 20 μm or less or an average fiber length of 20 μm or less. It is a fiber.
According to a third aspect of the present invention, there is provided a filter medium for an organic solvent or an organic cleaning agent, wherein the fine filler is made of an inorganic oxide which is stable in an organic solvent.
According to a fourth aspect of the present invention, there is provided a filter medium for an organic solvent or an organic cleaning agent, wherein the fine filler has an adsorption ability in the filter medium according to any one of the first to third aspects.
The filter medium for an organic solvent or an organic cleaning agent according to claim 5 is the filter medium according to claim 4, wherein the fine filler having the adsorptivity is selected from zeolite, potassium titanate, titanium oxide, sepiolite, and activated carbon. It is characterized by one or two or more of the above.
According to a sixth aspect of the present invention, there is provided a filter for an organic solvent or an organic cleaning agent, which comprises using the filter material according to any one of the first to fifth aspects. .
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
The filter medium for an organic solvent or an organic cleaning agent of the present invention contains an ultrahigh molecular weight polyethylene resin and a fine filler having heat resistance, has a through hole having an average pore diameter of 0.01 to 5 μm, and has a film thickness. Is a microporous membrane having a thickness of 25 to 300 μm.
That is, since the microporous membrane constituting the filter medium contains a fine filler having heat resistance, the dimensional stability of the microporous membrane in a hot atmosphere is improved, and the fine filler becomes Ultra-high molecular weight polyethylene resin, which functions as a material and furthermore, has extremely low thermal fluidity, connects and supports the fine filler which functions as an aggregate, so that shrinkage and blockage of micropores due to heating can be reduced. As a result, the heat resistance of the filter medium is improved.
[0007]
The ultrahigh molecular weight polyethylene resin used for the filter medium is preferably an ultrahigh molecular weight polyethylene resin having a weight average molecular weight of 1,000,000 or more, as calculated from the limiting viscosity method, and more preferably an ultrahigh molecular weight polyethylene resin having a weight average molecular weight of 2,000,000 or more. In addition, such an ultra-high molecular weight polyethylene resin has a very low heat fluidity, which causes poor processability and causes a decrease in extrusion productivity. In the present invention, a plasticizer is simultaneously compounded as described later. This enables extrusion and improves extrusion productivity. Further, as a polyethylene resin material having better thermal fluidity than such an ultra-high-molecular-weight polyethylene resin, a high-molecular-weight polyethylene resin having a weight average molecular weight of 200,000 to 900,000, also calculated from the limiting viscosity method, is used as a microporous membrane. Extrusion productivity can be further improved by using them together within a range that does not cause a significant decrease in mechanical strength.
[0008]
As the powder used as the fine filler, it is preferable to use a powder having an average secondary particle diameter of 20 μm or less, which is equal to or less than the thickness of the filter medium, from the viewpoint of uniform dispersibility in the film and defect-freeness of the film. Specifically, inorganic oxides such as silicon oxide, aluminum oxide, titanium oxide, and zirconium oxide, and powders such as activated carbon particles can be used. In addition, when an average secondary particle diameter of 20 μm or less cannot be obtained when synthesizing the inorganic oxide particles, a particle having a diameter of 20 μm or less is obtained by classification.
[0009]
The short fibers used as the fine filler are, as in the case of the powder, from the viewpoint of uniform dispersibility in the film and defect-free formation of the film, those having an average fiber length of 20 μm or less that is not more than the thickness of the filter medium. Preferably, it is used. Specifically, inorganic oxide-based short fibers such as potassium titanate whiskers and sepiolite fibers can be used.
In addition, as the fine filler, either one of the powder or the short fiber as described above may be used, or both may be used. As described above, from the viewpoint of making the fine filler function as the skeleton of the microporous membrane, since the fibrous material is more advantageous than the powdery material, it is better to increase the proportion of the short fibers. Although it can be said to be preferable, from the viewpoint of more uniform dispersion of the fine filler in the process of preparing the microporous film, the powdery material is more advantageous than the fibrous material. Is preferable. In the present invention, since the uniform dispersibility of the fine filler is a requirement that cannot be neglected, as a result, as the fine filler, use of the powder alone or uniform dispersion of the short fibers in the powder. It can be said that a form used in combination within a range that does not impair is preferable. In other words, when more importance is placed on uniform dispersibility, it is preferable to use the powder alone or in combination thereof, and when it is necessary to give more importance to skeleton formation, that is, heat resistance, an appropriate amount of the powder is used. It is preferable to use the short fibers in combination.
[0010]
As the fine filler, from the viewpoint of solvent resistance and heat resistance, it is preferable to use an inorganic oxide-based material, but any material that has resistance to an organic solvent to be filtered and does not undergo thermal deformation at an extrusion molding temperature. Alternatively, an organic material may be used.
Further, as the fine filler, it is possible to use a filler having an adsorption ability. By using a fine filler having an adsorbing ability for a filter medium, fine particulate impurities can be efficiently removed. Examples of the fine filler having such an adsorption ability include zeolite, potassium titanate, titanium oxide, sepiolite, and activated carbon.
[0011]
Next, an example of a method for producing a filter medium for an organic solvent or an organic cleaning agent of the present invention will be described.
(1) 0 to 40% by mass of a high molecular weight polyethylene resin having a weight average molecular weight of 200,000 to 900,000 calculated by the limiting viscosity method, and 20 to 40% by mass of an ultra high molecular weight polyethylene resin having a weight average molecular weight of 1 to 6,000,000 also calculated by the limiting viscosity method 40% by mass and 20 to 80% by mass of the heat-resistant fine filler are mixed, and an appropriate amount of a plasticizer is further added and mixed.
(2) The mixture is heated and melted and kneaded using a twin screw extruder to form a sheet. The thickness of the obtained sheet can be adjusted to 25 to 300 μm by secondary processing such as stretching or rolling.
(3) The filter medium of the present invention comprising a microporous membrane having through-holes having an average pore diameter of 0.01 to 5 μm is obtained by extracting and removing the plasticizer in the sheet using a suitable extractant and drying. can get.
[0012]
As the plasticizer, a mineral oil represented by an industrial lubricating oil composed of a saturated hydrocarbon, or a resin plasticizer represented by di-2-ethylhexyl phthalate can be used.
Examples of the extracting agent for extracting and removing the plasticizer include saturated hydrocarbon organic solvents such as hexane, heptane, octane, nonane, and decane, and halogenated organic solvents such as trichloroethylene and tetrachloroethylene. Can be used.
As described above, since the plasticizer also plays a role as a micropore forming agent, by adding a large amount of the plasticizer, the porosity of the filter medium can be set high and the filtration flow rate can be increased. , And the filtration performance of the filter medium can be improved, for example, the storage capacity of trapped impurities can be increased.
[0013]
Since the filter medium of the present invention has fine pores having an average pore size of 0.01 to 5 μm, fine particulate impurities can be removed, and the pore size distribution is uniform, so that the filtration accuracy is improved. Can be.
In addition, since the thickness of the filter medium of the present invention can be appropriately set in the range of 25 to 300 μm, the filter accuracy is improved by always obtaining a filter medium having a film thickness suitable for the object to be filtered. be able to.
[0014]
【Example】
Next, examples of the present invention will be described in detail together with comparative examples, but the present invention is not limited to these examples.
[0015]
(Example 1)
10% by mass of a high-molecular-weight polyethylene resin having a weight-average molecular weight of 300,000 calculated by the limiting viscosity method, 25% by mass of an ultra-high-molecular-weight polyethylene resin having a weight-average molecular weight of 2,000,000 also calculated by the limiting viscosity method, and an average secondary by a wet method To a mixture composed of 65% by mass of silicon oxide fine powder having a particle diameter of 10 μm, a mineral oil of twice the mass was added to the mixture and mixed using a Reedige mixer. The mixture was extruded into a sheet while being heated, melted and kneaded using a twin-screw extruder to obtain a sheet having a thickness of 200 μm. Next, the mineral oil in the sheet is extracted and removed using trichloroethylene, and further dried at 100 ° C. using a box drier. From the microporous membrane having an average pore diameter of 0.05 μm and a porosity of 70 vol%, Was obtained.
[0016]
(Example 2)
10% by mass of a high-molecular-weight polyethylene resin having a weight-average molecular weight of 300,000 calculated by the limiting viscosity method, 25% by mass of an ultra-high-molecular-weight polyethylene resin having a weight-average molecular weight of 2,000,000 also calculated by the limiting viscosity method, and an average secondary by a wet method To a mixture of 40% by mass of silicon oxide fine powder having a particle diameter of 10 μm and 25% by mass of potassium titanate whisker, a mineral oil was added in an amount twice as much as the mixture, and the mixture was mixed using a Reedige mixer. The mixture was extruded into a sheet while being heated, melted and kneaded using a twin-screw extruder to obtain a sheet having a thickness of 200 μm. Next, the mineral oil in the sheet is extracted and removed using trichloroethylene, and further dried at 100 ° C. using a box drier to obtain a microporous membrane having an average pore size of 0.07 μm and a porosity of 70% by volume. Was obtained.
[0017]
(Example 3)
10% by mass of a high-molecular-weight polyethylene resin having a weight-average molecular weight of 300,000 calculated by the limiting viscosity method, 25% by mass of an ultra-high-molecular-weight polyethylene resin having a weight-average molecular weight of 2,000,000 also calculated by the limiting viscosity method, and an average secondary by a wet method To a mixture composed of 65% by mass of silicon oxide fine powder having a particle diameter of 10 μm, a mineral oil of twice the mass was added to the mixture and mixed using a Reedige mixer. This mixture was extruded into a sheet while being heated, melted and kneaded using a twin-screw extruder to obtain a sheet having a thickness of 100 μm. Next, the sheet was stretched 4 times by a uniaxial stretching apparatus to obtain a sheet having a thickness of 25 μm. Next, the mineral oil in the sheet is extracted and removed using trichloroethylene, and further dried at 100 ° C. using a box drier to obtain a microporous membrane having an average pore diameter of 0.06 μm and a porosity of 85 vol%. Was obtained.
[0018]
(Comparative Example 1)
To 100% by mass of a high-molecular-weight polyethylene resin having a weight-average molecular weight of 300,000 calculated by the limiting viscosity method, twice the amount of mineral oil was added and mixed using a Reedige mixer. The mixture was extruded into a sheet while being heated, melted and kneaded using a twin-screw extruder to obtain a sheet having a thickness of 200 μm. Next, the mineral oil in the sheet is extracted and removed using trichloroethylene, and further dried at 100 ° C. using a box drier. From the microporous membrane having an average pore size of 0.05 μm and a porosity of 60% by volume, Was obtained.
[0019]
(Comparative Example 2)
A mixture of 80% by mass of a high molecular weight polyethylene resin having a weight average molecular weight of 300,000 calculated by the limiting viscosity method and 20% by mass of an ultra high molecular weight polyethylene resin having a weight average molecular weight of 2,000,000 also calculated by the limiting viscosity method, Was added and mixed using a Reedige mixer. The mixture was extruded into a sheet while being heated, melted and kneaded using a twin-screw extruder to obtain a sheet having a thickness of 200 μm. Next, the mineral oil in the sheet is extracted and removed using trichloroethylene, and further dried at 100 ° C. using a box drier. From the microporous membrane having an average pore size of 0.05 μm and a porosity of 60% by volume, Was obtained.
[0020]
(Comparative Example 3)
A mixture of 35% by mass of a high-molecular-weight polyethylene resin having a weight average molecular weight of 300,000 calculated by the limiting viscosity method and 65% by mass of a silicon oxide fine powder having an average secondary particle diameter of 10 μm by a wet method was added to the mixture. Twice the mass of mineral oil was added and mixed using a Reedige mixer. The mixture was extruded into a sheet while being heated, melted and kneaded using a twin-screw extruder to obtain a sheet having a thickness of 200 μm. Next, the mineral oil in the sheet is extracted and removed using trichloroethylene, and further dried at 100 ° C. using a box drier. From the microporous membrane having an average pore size of 0.05 μm and a porosity of 60% by volume, Was obtained.
[0021]
Next, the thickness, porosity, maximum pore size, average pore size, and heat shrinkage of each of the filter media of Examples 1 to 3 and Comparative Examples 1 to 3 thus obtained were measured. Table 1 shows the results.
[0022]
[Table 1]
Table 1 shows the following.
(1) In the filter media of Comparative Examples 1 to 3, heat shrinkage of about 20 to 30% occurs, whereas in the filter media of Examples 1 to 3, only heat shrinkage of about 1 to 5% occurs. Not. Therefore, the filter media of Examples 1 to 3 have a lower heat shrinkage than the filter media of Comparative Examples 1 to 3, and thus have improved heat resistance. In particular, in the filter medium of Example 2 in which a fiber-shaped potassium titanate whisker was used in combination with a powdery silicon oxide fine powder as a fine filler, the heat shrinkage rate was particularly high because the skeleton formation of the microporous membrane was good. Low and has excellent heat resistance.
(2) The porosity of the filter media of Examples 1 to 3 is about 16 to 42% larger than that of the filter media of Comparative Examples 1 to 3. Therefore, the filter media of Examples 1 to 3 have a higher porosity for retaining the trapped impurities and can increase the filtration flow rate as compared with the filter media of Comparative Examples 1 to 3. Filtration performance can be improved.
(3) Like the filter medium of Example 3, a filter medium having an arbitrary film thickness is obtained by stretching a filter medium containing a high-molecular-weight polyethylene resin, an ultra-high-molecular-weight polyethylene resin, and a fine filler. be able to.
[0024]
【The invention's effect】
As in the present invention, by mixing an ultra-high molecular weight polyethylene resin with a fine filler having excellent heat resistance, the heat resistance, which is a problem of the conventional polyethylene microporous membrane having excellent solvent resistance, is significantly improved. Can provide a filtered material for organic solvents or organic cleaning agents, which is a disadvantage of the PTFE membrane conventionally used as a filtering material for photoresist agents in semiconductor processes where solvent resistance and heat resistance are required. Is poor in wettability, difficult to dispose of, and the product price is very high), and is very valuable as a low-cost alternative to the conventional PTFE membrane.
Further, since the filter medium of the present invention contains a large amount of fine fillers, the porosity is larger than that of a microporous membrane made of ordinary polyethylene resin alone, and the specific surface area is significantly increased. When a secondary processing agent such as is kneaded or added later, the area for carrying the secondary processing agent increases, and thus there is an advantage that effects such as wettability are permanently exerted.
Claims (6)
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| JP2003068982A JP2004275845A (en) | 2003-03-13 | 2003-03-13 | Filter medium for organic solvent or organic detergent and its filter |
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| JP2003068982A JP2004275845A (en) | 2003-03-13 | 2003-03-13 | Filter medium for organic solvent or organic detergent and its filter |
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| JP2004275845A true JP2004275845A (en) | 2004-10-07 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8221921B2 (en) | 2007-03-26 | 2012-07-17 | Sony Corporation | Non-aqueous electrolyte battery |
| CN103381322A (en) * | 2013-06-25 | 2013-11-06 | 蚌埠凤凰滤清器有限责任公司 | Active carbon filter core and preparation method thereof |
| JP2014533197A (en) * | 2011-11-04 | 2014-12-11 | ピーピージー・インダストリーズ・オハイオ・インコーポレイテッドＰＰＧ Ｉｎｄｕｓｔｒｉｅｓ Ｏｈｉｏ，Ｉｎｃ． | Microporous materials with filtration and adsorption properties and their use in fluid purification processes |
| JP2015502246A (en) * | 2011-11-04 | 2015-01-22 | ピーピージー・インダストリーズ・オハイオ・インコーポレイテッドＰＰＧ Ｉｎｄｕｓｔｒｉｅｓ Ｏｈｉｏ，Ｉｎｃ． | Microporous materials with filtration and adsorption properties and their use in fluid purification processes |
| US9546326B2 (en) | 2011-11-04 | 2017-01-17 | Ppg Industries Ohio, Inc. | Fluid emulsion purification processes using microporous materials having filtration and adsorption properties |
| US9896353B2 (en) | 2011-11-04 | 2018-02-20 | Ppg Industries Ohio, Inc. | Hydrocarbon waste stream purification processes using microporous materials having filtration and adsorption properties |
| CN115138222A (en) * | 2021-03-30 | 2022-10-04 | 恩特格里斯公司 | Liquid purification membranes including carbonaceous materials and methods of forming the same |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63295650A (en) * | 1987-04-24 | 1988-12-02 | ピーピージー・インダストリーズ・インコーポレイテッド | Drawing microporous substance |
| JPH06170191A (en) * | 1992-06-22 | 1994-06-21 | Nikko Kogyo Kk | Porous membrane |
| JPH1050287A (en) * | 1996-07-31 | 1998-02-20 | Sony Corp | Nonaqueous electrolyte battery, separator for it, and manufacture of the separator |
| JP2000317280A (en) * | 1999-05-06 | 2000-11-21 | Teijin Ltd | Filter using ultrahigh molecular weight polyethylene porous membrane as filter medium |
| JP2002066268A (en) * | 2000-08-28 | 2002-03-05 | Fuji Photo Film Co Ltd | Chemical-resistant filter |
-
2003
- 2003-03-13 JP JP2003068982A patent/JP2004275845A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63295650A (en) * | 1987-04-24 | 1988-12-02 | ピーピージー・インダストリーズ・インコーポレイテッド | Drawing microporous substance |
| JPH06170191A (en) * | 1992-06-22 | 1994-06-21 | Nikko Kogyo Kk | Porous membrane |
| JPH1050287A (en) * | 1996-07-31 | 1998-02-20 | Sony Corp | Nonaqueous electrolyte battery, separator for it, and manufacture of the separator |
| JP2000317280A (en) * | 1999-05-06 | 2000-11-21 | Teijin Ltd | Filter using ultrahigh molecular weight polyethylene porous membrane as filter medium |
| JP2002066268A (en) * | 2000-08-28 | 2002-03-05 | Fuji Photo Film Co Ltd | Chemical-resistant filter |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8221921B2 (en) | 2007-03-26 | 2012-07-17 | Sony Corporation | Non-aqueous electrolyte battery |
| JP2014533197A (en) * | 2011-11-04 | 2014-12-11 | ピーピージー・インダストリーズ・オハイオ・インコーポレイテッドＰＰＧ Ｉｎｄｕｓｔｒｉｅｓ Ｏｈｉｏ，Ｉｎｃ． | Microporous materials with filtration and adsorption properties and their use in fluid purification processes |
| JP2015502246A (en) * | 2011-11-04 | 2015-01-22 | ピーピージー・インダストリーズ・オハイオ・インコーポレイテッドＰＰＧ Ｉｎｄｕｓｔｒｉｅｓ Ｏｈｉｏ，Ｉｎｃ． | Microporous materials with filtration and adsorption properties and their use in fluid purification processes |
| JP2016028817A (en) * | 2011-11-04 | 2016-03-03 | ピーピージー・インダストリーズ・オハイオ・インコーポレイテッドＰＰＧ Ｉｎｄｕｓｔｒｉｅｓ Ｏｈｉｏ，Ｉｎｃ． | Microporous material having filtration and adsorption properties and their use in fluid purification processes |
| US9546326B2 (en) | 2011-11-04 | 2017-01-17 | Ppg Industries Ohio, Inc. | Fluid emulsion purification processes using microporous materials having filtration and adsorption properties |
| US9896353B2 (en) | 2011-11-04 | 2018-02-20 | Ppg Industries Ohio, Inc. | Hydrocarbon waste stream purification processes using microporous materials having filtration and adsorption properties |
| CN103381322A (en) * | 2013-06-25 | 2013-11-06 | 蚌埠凤凰滤清器有限责任公司 | Active carbon filter core and preparation method thereof |
| CN103381322B (en) * | 2013-06-25 | 2015-07-22 | 安徽凤凰滤清器股份有限公司 | Active carbon filter core and preparation method thereof |
| CN115138222A (en) * | 2021-03-30 | 2022-10-04 | 恩特格里斯公司 | Liquid purification membranes including carbonaceous materials and methods of forming the same |
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