WO2021161800A1 - Hydrophilization agent, method for modifying hydrophobic porous film, and hydrophilic porous film - Google Patents

Hydrophilization agent, method for modifying hydrophobic porous film, and hydrophilic porous film Download PDF

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WO2021161800A1
WO2021161800A1 PCT/JP2021/003110 JP2021003110W WO2021161800A1 WO 2021161800 A1 WO2021161800 A1 WO 2021161800A1 JP 2021003110 W JP2021003110 W JP 2021003110W WO 2021161800 A1 WO2021161800 A1 WO 2021161800A1
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porous membrane
hydrophilic
hydrophobic porous
porous film
mass
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PCT/JP2021/003110
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French (fr)
Japanese (ja)
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吉田　俊也
利公 中西
麻依 菅原
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東洋濾紙株式会社
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F120/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F120/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F120/10—Esters
    • C08F120/26—Esters containing oxygen in addition to the carboxy oxygen
    • C08F120/28—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F299/00—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers
    • C08F299/02—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/36—After-treatment
    • C08J9/40—Impregnation
    • C08J9/42—Impregnation with macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K3/00—Materials not provided for elsewhere
    • 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
    • B01D71/38—Polyalkenylalcohols; Polyalkenylesters; Polyalkenylethers; Polyalkenylaldehydes; Polyalkenylketones; Polyalkenylacetals; Polyalkenylketals

Definitions

  • a method for producing a porous membrane having different internal properties from the surface properties by directly coating a crosslinked polymer formed from a polyfunctional monomer over the entire surface of a hydrophobic porous substrate for example, Patent Document 1.
  • Patent Document 2 a method of covering the inside of the pores of the porous membrane and the surface of the membrane with a crosslinked polymer containing polyethylene glycol diacrylate has been proposed (for example, Patent Document 2).
  • Patent Document 3 a solution containing a monofunctional acrylate monomer has been proposed.
  • the hydrophilic porous membrane obtained by modifying the hydrophobic porous membrane maintain the filtration rate of the hydrophobic porous membrane before modification as much as possible, that is, the filtration rate after modification has a high retention rate. Is done. Further, the hydrophilic porous membrane is required to have excellent wettability even after being placed in various environments and to have a small amount of total organic carbon (TOC) elution.
  • TOC total organic carbon
  • the present invention provides a hydrophilic porous film having a high maintenance rate of filtration rate after modification, excellent wettability even after being placed in various environments, and a reduced TOC elution amount. It is an object of the present invention to provide an agent, a method for modifying a hydrophobic porous film using such a hydrophilic agent, and a hydrophilic porous film.
  • hydrophobic porous with a hydrophilic agent consisting of an aqueous solution containing a specific bifunctional monomer and a thermal polymerization initiator in a predetermined amount.
  • a hydrophilic porous film having a high maintenance rate of filtration rate after modification, excellent wettability even after being placed in various environments, and a reduced TOC elution amount can be obtained. I found that.
  • the present invention is a method for modifying a hydrophobic porous film, which is a step of impregnating the hydrophobic porous film with the above-mentioned hydrophilic agent, and the above-mentioned hydrophobic porous film impregnated with the hydrophilic agent.
  • Hydrophobicity comprises a step of heating the film to 80 ° C. or higher, a step of washing the hydrophobic porous film after heating with pure water, and a step of drying the hydrophobic porous film after washing. This is a method for modifying a porous film.
  • the present invention is a hydrophilic porous membrane obtained by modifying a hydrophobic porous membrane by the above-mentioned method, and has a wet surface tension of 75 mN / m or more and a TOC elution amount of 200 ppb or less, defined by the following formula. It is a hydrophilic porous membrane characterized by having a filtration rate maintenance rate of 80% or more after modification.
  • a hydrophilic porous film having a high maintenance rate of filtration rate after modification, excellent wettability even after being placed in various environments, and a reduced TOC elution amount can be obtained.
  • An agent, a method for modifying a hydrophobic porous film using such a hydrophilic agent, and a hydrophilic porous film can be obtained.
  • the hydrophilic agent of the present invention comprises an aqueous solution containing 1.0 to 2.5% by mass of polyethylene glycol dimethacrylate and 0.5 to 2.0% by mass of a thermal polymerization initiator.
  • a thermal polymerization initiator 0.5 to 2.0% by mass of a thermal polymerization initiator.
  • polyethylene glycol dimethacrylate (PEGDMA) as a bifunctional monomer is represented by the following formula (1).
  • the molecular weight of PEGDMA represented by the above formula (1) is about 492 to 1180, preferably about 536 to 1136. More specifically, PEG400DMA, PEG600DMA, and PEG1000DMA can be mentioned. PEG400DMA, PEG600DMA and PEG1000DMA correspond to PEGDMA having n values of 9, 14 and 23 in the above formula (1), respectively. For example, two or more types of PEGDMA having different n values may be included around a predetermined n value in the range of 8 to 24.
  • the content of polyethylene glycol dimethacrylate in the aqueous solution is defined as 1.0 to 2.5% by mass. Even if the hydrophobic porous membrane is modified by using an aqueous solution containing less than 1.0% by mass of polyethylene glycol dimethacrylate as a hydrophilic agent, a hydrophilic porous membrane having excellent wettability cannot be obtained. On the other hand, if the polyethylene glycol dimethacrylate in the aqueous solution exceeds 2.5% by mass, the filtration rate of the hydrophilic porous membrane after the treatment cannot be maintained high.
  • the content of polyethylene glycol dimethacrylate is preferably 1.0 to 2.5% by mass, more preferably 1.5 to 2.0% by mass.
  • Ammonium persulfate is generally used as the thermal polymerization initiator, but potassium persulfate or the like can also be used.
  • the content of the thermal polymerization initiator in the aqueous solution is 0.5 to 2.0% by mass. If it is too small, no effect will be obtained, and if it is excessively contained, the effect will not be significantly increased.
  • the content of the thermal polymerization initiator is preferably 0.5 to 2.0% by mass, more preferably 0.8 to 1.2% by mass.
  • the hydrophilic agent of the present invention comprises an aqueous solution containing 1.0 to 2.5% by mass of polyethylene glycol dimethacrylate and 0.5 to 2.0% by mass of a thermal polymerization initiator, it is hydrophobically porous.
  • a hydrophilic porous film having a high maintenance rate of filtration rate after modification, excellent wettability, and a reduced TOC elution amount.
  • hydrophobic means the property that even if water is developed on the porous membrane, it does not soak into the porous membrane and becomes water droplets, and the porous membrane is 0.05 to 5. Refers to a film having fine pores of about 0 ⁇ m.
  • Specific examples of the hydrophobic porous membrane include a polyether sulfone (PES) membrane.
  • the method for modifying a hydrophobic porous film of the present invention is a step of impregnating the hydrophobic porous film with the hydrophilic agent of the present invention, and 80 of the hydrophobic porous film impregnated with the hydrophilic agent. It includes a step of heating to a temperature of ° C. or higher, a step of washing the hydrophobic porous film after heating with pure water, and a step of drying the hydrophobic porous film after washing.
  • each step will be described.
  • the hydrophobic porous membrane impregnated with the hydrophilic agent is sandwiched between plastic films and the like and heated at 80 ° C. or higher, preferably 85 to 95 ° C.
  • a hot plate can be used for heating, but the heating is not limited to this, and any means can be adopted.
  • the heating time can be appropriately selected according to the heating temperature. For example, in the case of 80 ° C., it can be 3 to 25 minutes. It is presumed that the hydrophilic agent forms a hydrophilic crosslinked polymer on the surface of the hydrophobic porous membrane by heating, and the hydrophobic porous membrane is modified into the hydrophilic porous membrane.
  • the water used here is preferably water having a specific resistance of 17.8 M ⁇ ⁇ cm or more. Further, it is preferably water at room temperature. By using such water as the washing water, it is possible to avoid the influence of TOC derived from the washing water and obtain a hydrophilic porous membrane in which the amount of TOC elution is reduced.
  • the drying temperature and time can be appropriately set according to the size of the reforming target. For example, when modifying a hydrophobic porous membrane having a diameter of 47 mm, it is sufficient to dry at 60 ° C. for 20 minutes.
  • the hydrophilic porous membrane of the present invention can be evaluated by the following method.
  • (Filtration rate) A hydrophilic porous membrane having a diameter of 47 mm is prepared. This hydrophilic porous membrane is fixed to a holder for vacuum filtration (effective filtration area 9.6 cm 2 ), and 200 mL of pure water is filtered under reduced pressure while applying a negative pressure of 69.3 kPa. The time (s) required for the entire amount of pure water to be filtered is measured and defined as t. Using the measured time t, the filtration rate (mL / min ⁇ cm 2 ) can be calculated by the following mathematical formula (2).
  • the hydrophilic porous membrane of the present invention has a post-modification filtration rate maintenance rate of 80% or more, preferably 85% or more.
  • the wet surface tension of the hydrophilic porous membrane of the present invention is 75 mN / m or more, preferably 80 mN / m or more, and more preferably 85 mN / m or more.
  • TOC elution amount A hydrophilic porous membrane having a diameter of 47 mm is fixed to a stainless steel holder (KST-47, manufactured by Toyo Filter Paper Co., Ltd.), ultrapure water is filtered, and about 100 mL of the filtrate is collected from the initial stream.
  • the TOC in the filtrate was measured using a wet oxidation TOC meter (TOC-Vws, manufactured by Shimadzu Corporation) and used as a sample value (TOC (s)).
  • TOC-Vws wet oxidation TOC meter
  • Ultrapure water was flowed using a stainless steel holder on which a hydrophilic porous membrane was not set, and the water recovered in the same manner was measured in the same manner to obtain a blank value (TOC (b)).
  • the TOC elution amount (ppb) was determined by ((TOC (s))-(TOC (b))).
  • the TOC elution amount of the hydrophilic porous membrane of the present invention is 200 ppb or less, preferably 100 ppb or less.
  • the hydrophilic porous membrane of the present invention is obtained by modifying the hydrophobic porous membrane with the hydrophilic agent of the present invention having a predetermined composition, the wet surface tension is 75 mN / m or more. It has the characteristics that the TOC elution amount is 200 ppb or less and the post-modification filtration rate maintenance rate defined by the above formula (1) is 80% or more.
  • PEGDMA Polyethylene glycol dimethacrylate
  • PEG1000DMA is a PEGDMA with a molecular weight of 1136
  • PEG400DMA is a PEGDMA with a molecular weight of 536
  • PEGDA Polyethylene glycol diacrylate
  • PEG600DA is a PEGDA with a molecular weight of 708.
  • APS Ammonium persulfate
  • HEMA Hydroxyethyl methacrylate
  • Sample 1 contains less than 1.0% by mass of bifunctional monomer, and Sample 6 contains more than 2.5% by mass of bifunctional monomer.
  • Sample 10 contains a monofunctional monomer.
  • the sample 11 is PEGDMA having a molecular weight of less than 690.
  • test membrane 1 and the test membrane 2 were made into circular test pieces having a diameter of 47 mm.
  • the test piece was immersed in the hydrophilic agent contained in the glass container for 1 minute, and the test piece was impregnated with the hydrophilic agent.
  • the test piece impregnated with the hydrophilic agent was sandwiched between two plastic films and heated at 90 ° C. for 5 minutes using a hot plate. After heating, the test piece is washed with water at room temperature having a specific resistance of 17.8 M ⁇ ⁇ cm or more for 10 minutes, and dried at 60 ° C. for 20 minutes or more using a blower dryer (FV-430, manufactured by Toyo Engineering Works, Ltd.). To obtain a hydrophilic porous membrane.
  • the filtration rate and the wet surface tension were determined in the same manner for the hydrophilic porous membrane after each treatment after washing with methanol, heating with steam, and immersing in hot alkali.
  • Methanol washing The hydrophilic porous membrane was washed by Soxhlet extraction using a Soxhlet extractor and methanol as a solvent for 16 hours or more.
  • Steam heating A hydrophilic porous membrane was placed in a stainless steel container and heated with steam at 140 ° C. for 30 minutes.
  • Thermo-alkali immersion The hydrophilic porous membrane was immersed in a 2 mass% sodium hydroxide aqueous solution at 90 ° C. for 2 hours, and then washed with running water for 10 minutes.
  • the hydrophilic porous membranes modified with the hydrophilic agents of Samples 2 to 5, 7 to 9, and 11 all have a filtration rate maintenance rate after modification.
  • the wet surface tension is 75 mN / m or more
  • the TOC elution amount is 200 ppb or less.
  • the hydrophilic agents of Samples 2 to 5, 7 to 9, and 11 all started thermal polymerization of PEGDMA as a bifunctional monomer in an amount of 1.0 to 2.5% by mass and 0.5 to 2.0% by mass. Since it is an aqueous solution containing an agent, a hydrophilic porous film having desired properties could be obtained.
  • the test membrane 1 when the sample 1 in which the bifunctional monomer is less than 1.0% by mass is used, the wettability is inferior, and the sample 6 in which the bifunctional monomer exceeds 2.5% by mass is used. After reforming, the filtration rate maintenance rate drops to 76%.
  • the sample 10 containing the monofunctional monomer is used, the wettability after modification is inferior, and the TOC elution amount is as large as 283 ppb.
  • Test Membrane 1 was modified by the same method as described above except that a hydrophilic agent using 2.5% by mass of PEG600DA as a bifunctional monomer and 1.0% by mass of a thermal polymerization initiator was used. The quality was obtained to obtain a hydrophilic porous membrane. The wet surface tension of the obtained hydrophilic porous membrane is evaluated in the same manner as described above, and the results are summarized in Table 9 below.

Abstract

The present invention is characterized by comprising an aqueous solution containing 1.0-2.5 mass% of a polyethylene glycol dimethacrylate and 0.5-2.0 mass% of a thermal polymerization initiator.

Description

親水性化剤、疎水性多孔質膜の改質方法および親水性多孔質膜Hydrophilic agent, method for modifying hydrophobic porous membrane and hydrophilic porous membrane
　本発明は、親水性化剤、疎水性多孔質膜の改質方法および親水性多孔質膜に関する。 The present invention relates to a hydrophilic agent, a method for modifying a hydrophobic porous membrane, and a hydrophilic porous membrane.
　疎水性の多孔質基材の表面全体にわたって、多官能モノマーから形成される架橋ポリマーを直接被覆することで、内部特性が表面特性と異なる多孔質膜を製造する方法が開示されている（例えば、特許文献１）。 A method is disclosed for producing a porous membrane having different internal properties from the surface properties by directly coating a crosslinked polymer formed from a polyfunctional monomer over the entire surface of a hydrophobic porous substrate (for example,). Patent Document 1).
　また、多孔質膜の孔内部および膜表面を、ポリエチレングリコールジアクリレートを含む架橋ポリマーにより覆う方法が提案されている（例えば、特許文献２）。親水性を高分子膜に付与するための溶液としては、単官能アクリレート・モノマーを含有する溶液が提案されている（例えば、特許文献３）。 Further, a method of covering the inside of the pores of the porous membrane and the surface of the membrane with a crosslinked polymer containing polyethylene glycol diacrylate has been proposed (for example, Patent Document 2). As a solution for imparting hydrophilicity to a polymer film, a solution containing a monofunctional acrylate monomer has been proposed (for example, Patent Document 3).
特開平７－５１５５０号公報Japanese Unexamined Patent Publication No. 7-51550 特開平９－１０５６４号公報Japanese Unexamined Patent Publication No. 9-10564 特開２００６－５２１９２６号公報Japanese Unexamined Patent Publication No. 2006-521926
　疎水性多孔質膜を改質して得られる親水性多孔質膜は、改質前の疎水性多孔質膜の濾過速度を極力維持すること、すなわち改質後濾過速度維持率の高いことが望まれる。さらに親水性多孔質膜は、様々な環境に置かれた後も優れた濡れ性を備えて、かつ、全有機炭素（Ｔｏｔａｌ　Ｏｒｇａｎｉｃ　Ｃａｒｂｏｎ：ＴＯＣ）の溶出が少ないことも求められる。 It is desirable that the hydrophilic porous membrane obtained by modifying the hydrophobic porous membrane maintain the filtration rate of the hydrophobic porous membrane before modification as much as possible, that is, the filtration rate after modification has a high retention rate. Is done. Further, the hydrophilic porous membrane is required to have excellent wettability even after being placed in various environments and to have a small amount of total organic carbon (TOC) elution.
　そこで本発明は、改質後濾過速度維持率が高く、様々な環境に置かれた後も優れた濡れ性を備え、かつＴＯＣ溶出量の低減された親水性多孔質膜が得られる親水性化剤、かかる親水性化剤を用いた疎水性多孔質膜の改質方法、および親水性多孔質膜を提供することを目的とする。 Therefore, according to the present invention, the present invention provides a hydrophilic porous film having a high maintenance rate of filtration rate after modification, excellent wettability even after being placed in various environments, and a reduced TOC elution amount. It is an object of the present invention to provide an agent, a method for modifying a hydrophobic porous film using such a hydrophilic agent, and a hydrophilic porous film.
　以上の目的を達成するため、本発明者らは、鋭意研究を重ねた結果、特定の二官能モノマーと熱重合開始剤とを所定の量で含有する水溶液からなる親水性化剤で疎水性多孔質膜を改質することによって、改質後濾過速度維持率が高く、様々な環境に置かれた後も優れた濡れ性を備え、ＴＯＣ溶出量の低減された親水性多孔質膜が得られることを見出した。 In order to achieve the above object, as a result of intensive studies, the present inventors have made hydrophobic porous with a hydrophilic agent consisting of an aqueous solution containing a specific bifunctional monomer and a thermal polymerization initiator in a predetermined amount. By modifying the quality film, a hydrophilic porous film having a high maintenance rate of filtration rate after modification, excellent wettability even after being placed in various environments, and a reduced TOC elution amount can be obtained. I found that.
　すなわち、本発明は、１．０～２．５質量％のポリエチレングリコールジメタクリレート、及び０．５～２．０質量％の熱重合開始剤を含有し水溶液からなることを特徴とする親水性化剤である。 That is, the present invention is characterized by containing 1.0 to 2.5% by mass of polyethylene glycol dimethacrylate and 0.5 to 2.0% by mass of a thermal polymerization initiator and comprising an aqueous solution. It is an agent.
　また本発明は、疎水性多孔質膜の改質方法であって、前述の親水性化剤を前記疎水性多孔質膜に含侵させる工程、前記親水性化剤が含浸した前記疎水性多孔質膜を８０℃以上に加熱する工程、加熱後の前記疎水性多孔質膜を純水で洗浄する工程、および洗浄後の前記疎水性多孔質膜を乾燥する工程を含むことを特徴とする疎水性多孔質膜の改質方法である。 Further, the present invention is a method for modifying a hydrophobic porous film, which is a step of impregnating the hydrophobic porous film with the above-mentioned hydrophilic agent, and the above-mentioned hydrophobic porous film impregnated with the hydrophilic agent. Hydrophobicity comprises a step of heating the film to 80 ° C. or higher, a step of washing the hydrophobic porous film after heating with pure water, and a step of drying the hydrophobic porous film after washing. This is a method for modifying a porous film.
　さらに本発明は、疎水性多孔質膜を、前述の方法により改質してなる親水性多孔質膜であって、湿潤表面張力が７５ｍＮ／ｍ以上、ＴＯＣ溶出量が２００ｐｐｂ以下、下記数式で定義される改質後濾過速度維持率が８０％以上であることを特徴とする親水性多孔質膜である。
Figure JPOXMLDOC01-appb-M000003
 Further, the present invention is a hydrophilic porous membrane obtained by modifying a hydrophobic porous membrane by the above-mentioned method, and has a wet surface tension of 75 mN / m or more and a TOC elution amount of 200 ppb or less, defined by the following formula. It is a hydrophilic porous membrane characterized by having a filtration rate maintenance rate of 80% or more after modification.
Figure JPOXMLDOC01-appb-M000003
　本発明によれば、改質後濾過速度維持率が高く、様々な環境に置かれた後も優れた濡れ性を備え、ＴＯＣ溶出量の低減された親水性多孔質膜が得られる親水性化剤、かかる親水性化剤を用いた疎水性多孔質膜の改質方法、および親水性多孔質膜を得ることができる。 According to the present invention, a hydrophilic porous film having a high maintenance rate of filtration rate after modification, excellent wettability even after being placed in various environments, and a reduced TOC elution amount can be obtained. An agent, a method for modifying a hydrophobic porous film using such a hydrophilic agent, and a hydrophilic porous film can be obtained.
　本発明の親水性化剤は、１．０～２．５質量％のポリエチレングリコールジメタクリレート、及び０．５～２．０質量％の熱重合開始剤を含有する水溶液からなる。
　以下、各成分について説明する。 The hydrophilic agent of the present invention comprises an aqueous solution containing 1.0 to 2.5% by mass of polyethylene glycol dimethacrylate and 0.5 to 2.0% by mass of a thermal polymerization initiator.
Hereinafter, each component will be described.
　二官能モノマーとしてのポリエチレングリコールジメタクリレート（ＰＥＧＤＭＡ）は、具体的には、下記式（１）で表される。 Specifically, polyethylene glycol dimethacrylate (PEGDMA) as a bifunctional monomer is represented by the following formula (1).
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　上記式（１）で表されるＰＥＧＤＭＡの分子量は、４９２～１１８０程度であり、５３６～１１３６程度が好ましい。より具体的には、ＰＥＧ４００ＤＭＡ、ＰＥＧ６００ＤＭＡ、およびＰＥＧ１０００ＤＭＡが挙げられる。ＰＥＧ４００ＤＭＡ、ＰＥＧ６００ＤＭＡおよびＰＥＧ１０００ＤＭＡは、上記式（１）において、ｎの値がそれぞれ９、１４および２３のＰＥＧＤＭＡに相当する。例えば、８から２４の範囲内の所定のｎ値を中心として、ｎ値の異なる２種以上のＰＥＧＤＭＡが含まれている場合もある。 The molecular weight of PEGDMA represented by the above formula (1) is about 492 to 1180, preferably about 536 to 1136. More specifically, PEG400DMA, PEG600DMA, and PEG1000DMA can be mentioned. PEG400DMA, PEG600DMA and PEG1000DMA correspond to PEGDMA having n values of 9, 14 and 23 in the above formula (1), respectively. For example, two or more types of PEGDMA having different n values may be included around a predetermined n value in the range of 8 to 24.
　水溶液中におけるポリエチレングリコールジメタクリレートの含有量は、１．０～２．５質量％に規定される。ポリエチレングリコールジメタクリレートが１．０質量％未満の水溶液を親水性化剤として用いて疎水性多孔質膜を改質しても、濡れ性の優れた親水性多孔質膜を得ることができない。一方、水溶液中のポリエチレングリコールジメタクリレートが２．５質量％を超えると、処理後の親水性多孔質膜の濾過速度を高く維持することができない。ポリエチレングリコールジメタクリレートの含有量は、好ましくは１．０～２．５質量％であり、より好ましくは１．５～２．０質量％である。 The content of polyethylene glycol dimethacrylate in the aqueous solution is defined as 1.0 to 2.5% by mass. Even if the hydrophobic porous membrane is modified by using an aqueous solution containing less than 1.0% by mass of polyethylene glycol dimethacrylate as a hydrophilic agent, a hydrophilic porous membrane having excellent wettability cannot be obtained. On the other hand, if the polyethylene glycol dimethacrylate in the aqueous solution exceeds 2.5% by mass, the filtration rate of the hydrophilic porous membrane after the treatment cannot be maintained high. The content of polyethylene glycol dimethacrylate is preferably 1.0 to 2.5% by mass, more preferably 1.5 to 2.0% by mass.
　熱重合開始剤としては、一般的には過硫酸アンモニウムが用いられるが、過硫酸カリウム等を用いることもできる。水溶液中における熱重合開始剤の含有量は、０．５～２．０質量％である。少なすぎる場合には効果が得られず、過剰に含有されても効果が顕著に増加するわけではない。熱重合開始剤の含有量は、好ましくは０．５～２．０質量％であり、より好ましくは０．８～１．２質量％である。 Ammonium persulfate is generally used as the thermal polymerization initiator, but potassium persulfate or the like can also be used. The content of the thermal polymerization initiator in the aqueous solution is 0.5 to 2.0% by mass. If it is too small, no effect will be obtained, and if it is excessively contained, the effect will not be significantly increased. The content of the thermal polymerization initiator is preferably 0.5 to 2.0% by mass, more preferably 0.8 to 1.2% by mass.
　本発明の親水性化剤は、１．０～２．５質量％のポリエチレングリコールジメタクリレート、及び０．５～２．０質量％の熱重合開始剤を含有する水溶液からなるので、疎水性多孔質膜の改質に用いた際には、改質後濾過速度維持率が高く優れた濡れ性を備え、ＴＯＣ溶出量の低減された親水性多孔質膜を得ることができる。 Since the hydrophilic agent of the present invention comprises an aqueous solution containing 1.0 to 2.5% by mass of polyethylene glycol dimethacrylate and 0.5 to 2.0% by mass of a thermal polymerization initiator, it is hydrophobically porous. When used for modifying the quality film, it is possible to obtain a hydrophilic porous film having a high maintenance rate of filtration rate after modification, excellent wettability, and a reduced TOC elution amount.
　本明細書において、疎水性とは水を多孔質膜の上に展開させても多孔質膜に浸み込まず、水滴状になる性質をさし、多孔質膜とは０．０５～５．０μｍ程度の微細孔を備えた膜をさす。疎水性多孔質膜としては、具体的には、ポリエーテルスルホン（ＰＥＳ）膜が挙げられる。 In the present specification, hydrophobic means the property that even if water is developed on the porous membrane, it does not soak into the porous membrane and becomes water droplets, and the porous membrane is 0.05 to 5. Refers to a film having fine pores of about 0 μm. Specific examples of the hydrophobic porous membrane include a polyether sulfone (PES) membrane.
　本発明の疎水性多孔質膜の改質方法は、本発明の親水性化剤を前記疎水性多孔質膜に含侵させる工程、前記親水性化剤が含浸した前記疎水性多孔質膜を８０℃以上に加熱する工程、加熱後の前記疎水性多孔質膜を純水で洗浄する工程、および、洗浄後の前記疎水性多孔質膜を乾燥する工程を含む。
　以下、各工程について説明する。 The method for modifying a hydrophobic porous film of the present invention is a step of impregnating the hydrophobic porous film with the hydrophilic agent of the present invention, and 80 of the hydrophobic porous film impregnated with the hydrophilic agent. It includes a step of heating to a temperature of ° C. or higher, a step of washing the hydrophobic porous film after heating with pure water, and a step of drying the hydrophobic porous film after washing.
Hereinafter, each step will be described.
　まず、容器に収容した親水性化剤中に疎水性多孔質膜を浸漬して、疎水性多孔質膜に親水性化剤を含浸させる。少なくとも１０秒浸漬させれば、親水性化剤は疎水性多孔質膜に含侵する。１分程度の浸漬によって、疎水性多孔質膜は親水性化剤で飽和することが予測される。親水性化剤の温度は特に規定されず、１５～３０℃の範囲内であれば疎水性多孔質膜に良好に含浸させることができる。 First, the hydrophobic porous membrane is immersed in the hydrophilic agent contained in the container, and the hydrophobic porous membrane is impregnated with the hydrophilic agent. After soaking for at least 10 seconds, the hydrophilic agent invades the hydrophobic porous membrane. It is predicted that the hydrophobic porous membrane will be saturated with the hydrophilic agent by soaking for about 1 minute. The temperature of the hydrophilic agent is not particularly specified, and the hydrophobic porous membrane can be satisfactorily impregnated within the range of 15 to 30 ° C.
　親水性化剤が含浸した疎水性多孔質膜は、プラスチックフィルム等で挟持して８０℃以上、好ましくは８５～９５℃で加熱する。加熱には、ホットプレートを用いることができるが、これに限定されず、任意の手段を採用することができる。加熱時間は、加熱温度に応じて適宜選択することができる。例えば８０℃の場合には、３～２５分とすることができる。
　加熱によって、親水性化剤は、親水性架橋ポリマーを疎水性多孔質膜の表面に形成し、疎水性多孔質膜は親水性多孔質膜に改質されるものと推測される。 The hydrophobic porous membrane impregnated with the hydrophilic agent is sandwiched between plastic films and the like and heated at 80 ° C. or higher, preferably 85 to 95 ° C. A hot plate can be used for heating, but the heating is not limited to this, and any means can be adopted. The heating time can be appropriately selected according to the heating temperature. For example, in the case of 80 ° C., it can be 3 to 25 minutes.
It is presumed that the hydrophilic agent forms a hydrophilic crosslinked polymer on the surface of the hydrophobic porous membrane by heating, and the hydrophobic porous membrane is modified into the hydrophilic porous membrane.
　親水性多孔質膜は、流水で５分以上洗浄する。ここで用いる水は、比抵抗が１７．８ＭΩ・ｃｍ以上の水であることが好ましい。また、常温の水であることが好ましい。こうした水を洗浄水として用いることによって、洗浄水に由来するＴＯＣの影響を回避して、ＴＯＣ溶出量の低減された親水性多孔質膜を得ることができる。 Wash the hydrophilic porous membrane with running water for 5 minutes or more. The water used here is preferably water having a specific resistance of 17.8 MΩ · cm or more. Further, it is preferably water at room temperature. By using such water as the washing water, it is possible to avoid the influence of TOC derived from the washing water and obtain a hydrophilic porous membrane in which the amount of TOC elution is reduced.
　洗浄後の親水性多孔質膜を乾燥させて、水分を除去する。乾燥の温度および時間は、改質対象のサイズに応じて、適宜設定することができる。例えば、直径４７ｍｍの疎水性多孔質膜を改質する場合には、６０℃で２０分間乾燥させれば十分である。 Dry the hydrophilic porous membrane after washing to remove water. The drying temperature and time can be appropriately set according to the size of the reforming target. For example, when modifying a hydrophobic porous membrane having a diameter of 47 mm, it is sufficient to dry at 60 ° C. for 20 minutes.
　本発明の方法により疎水性多孔質膜を改質して得られた親水性多孔質膜は、湿潤表面張力が７５ｍＮ／ｍ以上であり、ＴＯＣ溶出量が２００ｐｐｂ以下であり、下記数式で定義される改質後濾過速度維持率が８０％以上である。 The hydrophilic porous membrane obtained by modifying the hydrophobic porous membrane by the method of the present invention has a wet surface tension of 75 mN / m or more and a TOC elution amount of 200 ppb or less, and is defined by the following mathematical formula. The filtration rate maintenance rate after reforming is 80% or more.
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　本発明の親水性多孔質膜は、以下の手法により評価することができる。
（濾過速度）
　直径４７ｍｍの親水性多孔質膜を用意する。この親水性多孔質膜を、減圧濾過用ホルダー（有効濾過面積９．６ｃｍ2）に固定し、６９．３ｋＰａの負圧を印加しつつ２００ｍＬの純水を減圧濾過する。全量の純水が濾過されるまでに要した時間（ｓ）を測定して、ｔとする。測定された時間ｔを用いて、下記数式（２）によって、濾過速度（ｍＬ／ｍｉｎ・ｃｍ2）を算出することができる。 The hydrophilic porous membrane of the present invention can be evaluated by the following method.
(Filtration rate)
A hydrophilic porous membrane having a diameter of 47 mm is prepared. This hydrophilic porous membrane is fixed to a holder for vacuum filtration (effective filtration area 9.6 cm 2 ), and 200 mL of pure water is filtered under reduced pressure while applying a negative pressure of 69.3 kPa. The time (s) required for the entire amount of pure water to be filtered is measured and defined as t. Using the measured time t, the filtration rate (mL / min · cm 2 ) can be calculated by the following mathematical formula (2).
Figure JPOXMLDOC01-appb-M000006
Figure JPOXMLDOC01-appb-M000006
　改質前の疎水性多孔質膜についても同様にして濾過速度を求め、上記数式（１）により改質後濾過速度維持率（％）を算出する。本発明の親水性多孔質膜は、こうして求められる改質後濾過速度維持率が、８０％以上であり、８５％以上であることが好ましい。 For the hydrophobic porous membrane before modification, the filtration rate is obtained in the same manner, and the filtration rate maintenance rate (%) after modification is calculated by the above formula (1). The hydrophilic porous membrane of the present invention has a post-modification filtration rate maintenance rate of 80% or more, preferably 85% or more.
（湿潤表面張力）
　試験液として、表面張力の値が既知の塩化カルシウム水溶液を用いて測定する。親水性多孔質膜の表面に１０滴（約１０μＬ／滴）の試験液を滴下して、１０分間安置する。その後、９滴以上の液滴が浸透する試験液の最大の表面張力の値を、親水性多孔質膜の湿潤表面張力の値とする。
　本発明の親水性多孔質膜の湿潤表面張力は、７５ｍＮ／ｍ以上であり、８０ｍＮ／ｍ以上が好ましく、８５ｍＮ／ｍ以上であることがより好ましい。 (Wet surface tension)
As a test solution, an aqueous solution of calcium chloride having a known surface tension value is used for measurement. 10 drops (about 10 μL / drop) of the test solution is added dropwise to the surface of the hydrophilic porous membrane, and the mixture is allowed to stand for 10 minutes. Then, the value of the maximum surface tension of the test solution in which 9 or more droplets permeate is taken as the value of the wet surface tension of the hydrophilic porous membrane.
The wet surface tension of the hydrophilic porous membrane of the present invention is 75 mN / m or more, preferably 80 mN / m or more, and more preferably 85 mN / m or more.
（ＴＯＣ溶出量）
　直径４７ｍｍの親水性多孔質膜をステンレスホルダー（ＫＳＴ-４７、東洋濾紙（株）製）に固定して超純水を濾過し、初流から約１００ｍＬの濾液を回収する。湿式酸化方式ＴＯＣ計（ＴＯＣ－Ｖｗｓ、（株）島津製作所製）を用いて、濾液中のＴＯＣを測定し、サンプル値（ＴＯＣ(s)）とした。親水性多孔質膜をセットしないステンレスホルダーを用いて超純水を流し、同様に回収した水について同様に測定して、ブランク値（ＴＯＣ(ｂ)）とした。 (TOC elution amount)
A hydrophilic porous membrane having a diameter of 47 mm is fixed to a stainless steel holder (KST-47, manufactured by Toyo Filter Paper Co., Ltd.), ultrapure water is filtered, and about 100 mL of the filtrate is collected from the initial stream. The TOC in the filtrate was measured using a wet oxidation TOC meter (TOC-Vws, manufactured by Shimadzu Corporation) and used as a sample value (TOC (s)). Ultrapure water was flowed using a stainless steel holder on which a hydrophilic porous membrane was not set, and the water recovered in the same manner was measured in the same manner to obtain a blank value (TOC (b)).
　ＴＯＣ溶出量（ｐｐｂ）は、（（ＴＯＣ(s)）－（ＴＯＣ(b)））により求めた。本発明の親水性多孔質膜のＴＯＣ溶出量は、２００ｐｐｂ以下であり、１００ｐｐｂ以下であることが好ましい。 The TOC elution amount (ppb) was determined by ((TOC (s))-(TOC (b))). The TOC elution amount of the hydrophilic porous membrane of the present invention is 200 ppb or less, preferably 100 ppb or less.
　本発明の親水性多孔質膜は、所定の組成を有する本発明の親水性化剤により疎水性多孔質膜を改質して得られたものであるので、湿潤表面張力が７５ｍＮ／ｍ以上、ＴＯＣ溶出量が２００ｐｐｂ以下、上記数式（１）で定義される改質後濾過速度維持率が８０％以上という特性を備えている。 Since the hydrophilic porous membrane of the present invention is obtained by modifying the hydrophobic porous membrane with the hydrophilic agent of the present invention having a predetermined composition, the wet surface tension is 75 mN / m or more. It has the characteristics that the TOC elution amount is 200 ppb or less and the post-modification filtration rate maintenance rate defined by the above formula (1) is 80% or more.
　以下、本発明を実施例に基づいて具体的に説明するが、これらは本発明の目的を限定するものではなく、また、本発明は、これら実施例に限定されるものではない。 Hereinafter, the present invention will be specifically described based on examples, but these do not limit the object of the present invention, and the present invention is not limited to these examples.
　親水性化剤の調製に用いる成分を、略称とともに以下に示す。
＜二官能モノマー＞
　　　　ＰＥＧＤＭＡ：ポリエチレングリコールジメタクリレート
　ＰＥＧ６００ＤＭＡは、分子量７３６のＰＥＧＤＭＡであり、ＰＥＧ１０００ＤＭＡは、分子量１１３６のＰＥＧＤＭＡであり、ＰＥＧ４００ＤＭＡは、分子量５３６のＰＥＧＤＭＡである。
　　　　ＰＥＧＤＡ：ポリエチレングリコールジアクリレート
　ＰＥＧ６００ＤＡは、分子量７０８のＰＥＧＤＡである。
＜熱重合開始剤＞
　　　　ＡＰＳ：過硫酸アンモニウム
＜単官能モノマー＞
　　　　ＨＥＭＡ：ヒドロキシエチルメタクリレート The components used for the preparation of the hydrophilic agent are shown below together with abbreviations.
<Bifunctional monomer>
PEGDMA: Polyethylene glycol dimethacrylate PEG600DMA is a PEGDMA with a molecular weight of 736, PEG1000DMA is a PEGDMA with a molecular weight of 1136, and PEG400DMA is a PEGDMA with a molecular weight of 536.
PEGDA: Polyethylene glycol diacrylate PEG600DA is a PEGDA with a molecular weight of 708.
<Thermal polymerization initiator>
APS: Ammonium persulfate <monofunctional monomer>
HEMA: Hydroxyethyl methacrylate
　１．疎水性多孔質膜の作製
　改質処理の対象となる疎水性多孔質膜を、公知の湿式相分離法にてポリエーテルサルホンを主成分とする精密濾過膜を作製した。得られた膜の性能を下記表１に示す。 1. 1. Preparation of Hydrophobic Porous Membrane A microfiltration membrane containing polyether sulfone as a main component was prepared by a known wet phase separation method for the hydrophobic porous membrane to be modified. The performance of the obtained film is shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　２．親水性化剤の作製
　下記表２～４に示す処方で各成分を溶媒としての水に溶解して、親水性化剤の試料１～１１を調製した。 2. Preparation of Hydrophilic Agent Samples 1 to 11 of the hydrophilic agent were prepared by dissolving each component in water as a solvent according to the formulations shown in Tables 2 to 4 below.
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　試料１～１１のうち、試料１は二官能モノマーが１．０質量％未満であり、試料６は二官能モノマーが２．５質量％を超えている。試料１０には単官能モノマーが含有されている。また、試料１１は分子量６９０未満のＰＥＧＤＭＡである。 Of Samples 1 to 11, Sample 1 contains less than 1.0% by mass of bifunctional monomer, and Sample 6 contains more than 2.5% by mass of bifunctional monomer. Sample 10 contains a monofunctional monomer. Further, the sample 11 is PEGDMA having a molecular weight of less than 690.
　３．疎水性多孔質膜の改質処理
　試験膜１および試験膜２を直径４７ｍｍの円形の試験片とした。 3. 3. Modification Treatment of Hydrophobic Porous Membrane The test membrane 1 and the test membrane 2 were made into circular test pieces having a diameter of 47 mm.
　改質処理に当たっては、ガラス容器内に収容した親水性化剤中に試験片を１分間浸漬して、試験片に親水性化剤を含浸させた。親水性化剤が含浸した試験片は、２枚のプラスチックフィルムで挟持し、ホットプレートを用いて９０℃で５分間加熱した。
　加熱後の試験片は、比抵抗１７．８ＭΩ・ｃｍ以上の常温の水で１０分洗浄し、送風乾燥器（ＦＶ－４３０、（株）東洋製作所製）を用いて６０℃で２０分間以上乾燥させて、親水性多孔質膜を得た。 In the modification treatment, the test piece was immersed in the hydrophilic agent contained in the glass container for 1 minute, and the test piece was impregnated with the hydrophilic agent. The test piece impregnated with the hydrophilic agent was sandwiched between two plastic films and heated at 90 ° C. for 5 minutes using a hot plate.
After heating, the test piece is washed with water at room temperature having a specific resistance of 17.8 MΩ · cm or more for 10 minutes, and dried at 60 ° C. for 20 minutes or more using a blower dryer (FV-430, manufactured by Toyo Engineering Works, Ltd.). To obtain a hydrophilic porous membrane.
　４．親水性多孔質膜の性能評価
　得られた親水性多孔質膜について、上述した方法により濾過速度を測定して、改質後濾過速度維持率（％）を算出した。さらに、湿潤表面張力（ｍＮ／ｍ）およびＴＯＣ溶出量（ｐｐｂ）を求めた。 4. Performance Evaluation of Hydrophilic Porous Membrane With respect to the obtained hydrophilic porous membrane, the filtration rate was measured by the method described above, and the filtration rate maintenance rate (%) after modification was calculated. Furthermore, the wet surface tension (mN / m) and the TOC elution amount (ppb) were determined.
　濾過速度および湿潤表面張力は、メタノール洗浄後、蒸気加熱後、および熱アルカリ浸漬後の各処理後の親水性多孔質膜についても同様にして求めた。なお、各処理の詳細は以下のとおりである。
メタノール洗浄：親水性多孔質膜を、ソックスレー抽出器を用い、溶媒としてメタノールを用いて、１６時間以上ソックスレー抽出を行って洗浄した。
蒸気加熱：親水性多孔質膜を、ステンレス容器内にいれ、１４０℃の蒸気にて、３０分間加熱した。
熱アルカリ浸漬：親水性多孔質膜を、９０℃の２質量％水酸化ナトリウム水溶液に２時間、浸漬し、その後１０分間流水洗浄した。 The filtration rate and the wet surface tension were determined in the same manner for the hydrophilic porous membrane after each treatment after washing with methanol, heating with steam, and immersing in hot alkali. The details of each process are as follows.
Methanol washing: The hydrophilic porous membrane was washed by Soxhlet extraction using a Soxhlet extractor and methanol as a solvent for 16 hours or more.
Steam heating: A hydrophilic porous membrane was placed in a stainless steel container and heated with steam at 140 ° C. for 30 minutes.
Thermo-alkali immersion: The hydrophilic porous membrane was immersed in a 2 mass% sodium hydroxide aqueous solution at 90 ° C. for 2 hours, and then washed with running water for 10 minutes.
　疎水性多孔質膜としての試験膜１を、試料１～１１の各親水性化剤で処理した結果を、下記表５～７にまとめる。 The results of treating the test membrane 1 as the hydrophobic porous membrane with each of the hydrophilic agents of Samples 1 to 11 are summarized in Tables 5 to 7 below.
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000013
　疎水性多孔質膜としての試験膜２を、試料３～５、試料１１の各親水性化剤で処理した結果を、下記表８にまとめる。 The results of treating the test membrane 2 as the hydrophobic porous membrane with each of the hydrophilic agents of Samples 3 to 5 and Sample 11 are summarized in Table 8 below.
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000014
　上記表５～８に示されるように、試料２～５、７～９、１１の親水性化剤を用いて改質処理した親水性多孔質膜は、いずれも改質後濾過速度維持率が８０％以上で、湿潤表面張力は７５ｍＮ／ｍ以上であり、ＴＯＣ溶出量は２００ｐｐｂ以下である。試料２～５、７～９、１１の親水性化剤は、いずれも二官能モノマーとしてのＰＥＧＤＭＡを１．０～２．５質量％と、０．５～２．０質量％の熱重合開始剤とを含有した水溶液であるので、所望の特性を備えた親水性多孔質膜を得ることができた。 As shown in Tables 5 to 8 above, the hydrophilic porous membranes modified with the hydrophilic agents of Samples 2 to 5, 7 to 9, and 11 all have a filtration rate maintenance rate after modification. At 80% or more, the wet surface tension is 75 mN / m or more, and the TOC elution amount is 200 ppb or less. The hydrophilic agents of Samples 2 to 5, 7 to 9, and 11 all started thermal polymerization of PEGDMA as a bifunctional monomer in an amount of 1.0 to 2.5% by mass and 0.5 to 2.0% by mass. Since it is an aqueous solution containing an agent, a hydrophilic porous film having desired properties could be obtained.
　これに対し、試験膜１の場合では、二官能モノマーが１．０質量％未満の試料１を用いた場合は濡れ性が劣り、二官能モノマーが２．５質量％を超えた試料６を用いると改質後濾過速度維持率が７６％に低下する。単官能モノマーを含む試料１０を用いると改質後の濡れ性が劣り、ＴＯＣ溶出量が２８３ｐｐｂと大きい。 On the other hand, in the case of the test membrane 1, when the sample 1 in which the bifunctional monomer is less than 1.0% by mass is used, the wettability is inferior, and the sample 6 in which the bifunctional monomer exceeds 2.5% by mass is used. After reforming, the filtration rate maintenance rate drops to 76%. When the sample 10 containing the monofunctional monomer is used, the wettability after modification is inferior, and the TOC elution amount is as large as 283 ppb.
　比較のために、二官能モノマーとして２．５質量％のＰＥＧ６００ＤＡ、熱重合開始剤として１．０質量％を用いた親水性化剤を用いる以外は前述と同様の手法により、試験膜１を改質して親水性多孔質膜を得た。得られた親水性多孔質膜の湿潤表面張力を前述と同様に評価し、その結果を下記表９にまとめる。 For comparison, Test Membrane 1 was modified by the same method as described above except that a hydrophilic agent using 2.5% by mass of PEG600DA as a bifunctional monomer and 1.0% by mass of a thermal polymerization initiator was used. The quality was obtained to obtain a hydrophilic porous membrane. The wet surface tension of the obtained hydrophilic porous membrane is evaluated in the same manner as described above, and the results are summarized in Table 9 below.
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000015
　上記表９に示されるように、二官能モノマーとしてＰＥＧＤＡを用いた親水性化剤により改質処理した場合には、熱アルカリ浸漬後において濡れ性が著しく低下し、濡れ性に劣ることが示されている。 As shown in Table 9 above, it was shown that when the modification treatment was carried out with a hydrophilic agent using PEGDA as a bifunctional monomer, the wettability was significantly reduced after immersion in hot alkali, and the wettability was inferior. ing.

Claims (4)

  1. 　１．０～２．５質量％のポリエチレングリコールジメタクリレート及び
    　０．５～２．０質量％の熱重合開始剤を含有する水溶液からなることを特徴とする親水性化剤。     A hydrophilic agent comprising an aqueous solution containing 1.0 to 2.5% by mass of polyethylene glycol dimethacrylate and 0.5 to 2.0% by mass of a thermal polymerization initiator.
  2. 　前記ポリエチレングリコールジメタクリレートは、下記式（１）で表されることを特徴とする請求項２記載の親水性化剤。
    Figure JPOXMLDOC01-appb-C000001
         The hydrophilic agent according to claim 2, wherein the polyethylene glycol dimethacrylate is represented by the following formula (1).
    Figure JPOXMLDOC01-appb-C000001
  3. 　疎水性多孔質膜の改質方法であって、
    　　請求項１～２のいずれか記載の親水性化剤を前記疎水性多孔質膜に含侵させる工程、
    　　前記親水性化剤が含浸した前記疎水性多孔質膜を８０℃以上に加熱する工程、
    　　加熱後の前記疎水性多孔質膜を純水で洗浄する工程、および
    　　洗浄後の前記疎水性多孔質膜を乾燥する工程
    を含むことを特徴とする疎水性多孔質膜の改質方法。     A method for modifying a hydrophobic porous membrane,
    The step of impregnating the hydrophobic porous membrane with the hydrophilic agent according to any one of claims 1 and 2.
    A step of heating the hydrophobic porous membrane impregnated with the hydrophilic agent to 80 ° C. or higher.
    A method for modifying a hydrophobic porous membrane, which comprises a step of washing the hydrophobic porous membrane after heating with pure water and a step of drying the hydrophobic porous membrane after washing.
  4. 　疎水性多孔質膜を、請求項３の方法により改質してなる親水性多孔質膜であって、
    　湿潤表面張力が７５ｍＮ／ｍ以上、
    　ＴＯＣ溶出量が２００ｐｐｂ以下、
    　下記数式で定義される改質後濾過速度維持率が８０％以上である
    ことを特徴とする親水性多孔質膜。
    Figure JPOXMLDOC01-appb-M000002

          A hydrophilic porous membrane obtained by modifying a hydrophobic porous membrane by the method of claim 3.
    Wet surface tension of 75 mN / m or more,
    TOC elution amount is 200 ppb or less,
    A hydrophilic porous membrane characterized by having a filtration rate maintenance rate after modification of 80% or more as defined by the following formula.
    Figure JPOXMLDOC01-appb-M000002

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0369673A (en) * 1989-08-07 1991-03-26 Mitsubishi Rayon Co Ltd Heat-resistant hydrophilic porous polyolefin hollow fiber
JPH0824602A (en) * 1994-07-08 1996-01-30 Chikyu Kankyo Sangyo Gijutsu Kenkyu Kiko Surface-improve gas separation membrane and its preparation
JPH11188247A (en) * 1997-10-27 1999-07-13 Pall Corp Hydrophilic membrane
JP2013534464A (en) * 2010-06-01 2013-09-05 スリーエム イノベイティブ プロパティズ カンパニー Coated porous material

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0369673A (en) * 1989-08-07 1991-03-26 Mitsubishi Rayon Co Ltd Heat-resistant hydrophilic porous polyolefin hollow fiber
JPH0824602A (en) * 1994-07-08 1996-01-30 Chikyu Kankyo Sangyo Gijutsu Kenkyu Kiko Surface-improve gas separation membrane and its preparation
JPH11188247A (en) * 1997-10-27 1999-07-13 Pall Corp Hydrophilic membrane
JP2013534464A (en) * 2010-06-01 2013-09-05 スリーエム イノベイティブ プロパティズ カンパニー Coated porous material

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