JP2006192364A - Vapor permeable membrane - Google Patents
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- JP2006192364A JP2006192364A JP2005006046A JP2005006046A JP2006192364A JP 2006192364 A JP2006192364 A JP 2006192364A JP 2005006046 A JP2005006046 A JP 2005006046A JP 2005006046 A JP2005006046 A JP 2005006046A JP 2006192364 A JP2006192364 A JP 2006192364A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
Description
本発明は、燃料電池に供給する原料気体を加湿するのに好適に用いられる水蒸気透過膜に関する。 The present invention relates to a water vapor permeable membrane suitably used for humidifying a raw material gas supplied to a fuel cell.
燃料電池は、水素やメタノール等の燃料を電気化学的に酸化することによって電気エネルギーを取り出す一種の発電装置であり、近年、クリーンなエネルギー供給源として注目されている。燃料電池は、用いられる電解質の種類によって、リン酸型、溶融炭酸塩型、固体酸化物型、固体高分子電解質型等に分類されるが、このうち、固体高分子電解質は、標準的な作動温度が１００℃以下と低く、エネルギー密度が高いことから、電気自動車などの電源として幅広い応用が期待されている。
この固体高分子電解質型燃料電池の基本構成は、一般に、電池反応を行う電池部と、電池部へ供給する原料気体を加湿する加湿部を備えた構造となっている。
原料気体は高い圧力で燃料電池に供給されるが、これは、燃料電池本体と気体流路での圧力損失を考慮しており、結果として、加湿部の原料気体用流路部と、電池から排出される気体が導入される排出気体用流路部には圧力差が発生する。この圧力差によって水蒸気透過膜を介した原料気体のリークが発生すると、燃料電池へ原料気体を供給するコンプレッサの負荷が増大するので好ましくない。従って加湿部に用いられる水蒸気透過膜には、水蒸気透過性能は勿論の事、耐リーク性も要求される。
加湿部に用いられる水蒸気透過膜の厚さは薄いほうが良いとされてきたが、それは水分が水蒸気透過膜を透過する際の移動距離が短いほど水分の透過速度が上昇することと、一般に高い水蒸気透過性能を示す為に水蒸気透過膜の材料として用いられるパーフルオロスルホン酸系イオン交換樹脂が非常に高価な材料であることからその使用量を出来る限り減らして製造コストを抑える為である。
BACKGROUND ART A fuel cell is a kind of power generator that extracts electric energy by electrochemically oxidizing a fuel such as hydrogen or methanol, and has recently attracted attention as a clean energy supply source. Fuel cells are classified into phosphoric acid type, molten carbonate type, solid oxide type, solid polymer electrolyte type, etc., depending on the type of electrolyte used. Since the temperature is as low as 100 ° C. or less and the energy density is high, a wide range of applications are expected as a power source for electric vehicles and the like.
The basic configuration of the solid polymer electrolyte fuel cell generally has a structure including a battery part that performs a battery reaction and a humidifying part that humidifies a raw material gas supplied to the battery part.
The raw material gas is supplied to the fuel cell at a high pressure, which takes into account the pressure loss in the fuel cell main body and the gas flow path, and as a result, from the raw material gas flow path section of the humidifying section and the battery. A pressure difference is generated in the exhaust gas passage portion into which the exhausted gas is introduced. If the raw material gas leaks through the water vapor permeable membrane due to this pressure difference, the load on the compressor that supplies the raw material gas to the fuel cell increases, which is not preferable. Therefore, the water vapor permeable membrane used in the humidifying part is required to have not only water vapor permeation performance but also leak resistance.
It has been said that the thickness of the water vapor permeable membrane used in the humidifying part should be thin. However, the shorter the moving distance when the moisture permeates the water vapor permeable membrane, the higher the moisture transmission rate, This is because the perfluorosulfonic acid ion exchange resin used as the material for the water vapor permeable membrane in order to show the permeation performance is a very expensive material, so that the amount used is reduced as much as possible to reduce the manufacturing cost.
しかしながら、薄いパーフルオロスルホン酸系イオン交換膜単独で使用するには、必要な機械的強度や耐リーク性を与える為に一定の厚みを持たせなければならない。その為、水蒸気透過膜の厚さを薄くするには限度があった。
これらの問題を解決する為に、特許文献１では、表面に硬化したパーフルオロスルホン酸系イオン交換樹脂からなる透湿性樹脂層を設けた構造が開示されている。
また、特許文献２では、スルホン酸系イオン交換樹脂をポリエチレン製多孔質基体中空糸に塗布した後に乾燥させた実施例が開示されている。
しかしながら、これらのイオン交換樹脂を用いた水蒸気透過膜は、対イオンがプロトン型の場合に示す高い水蒸気透過性能を利用したものであるが、充分な耐リーク性を得るに至っていない。また、自動車用燃料電池などの高出力の燃料電池に用いられる加湿装置では、最大で数千リットル／分という大多量の原料空気を通気させる必要があり、その場合には、原料空気中に存在する吸着性物質の影響が顕著となり、経時的に水蒸気透過性能が低下する。また、運転環境温度が高くなると、熱によるイオン交換樹脂の構造変化が起こり、含水率が低下し、経時的に水蒸気透過性能が低下する。
また、特許文献３では、イオン交換基の対イオンが金属で置換されたイオン交換樹脂を用いた除湿膜が開示されている。該特許文献では除湿性能を維持したまま基材の耐圧強度を向上させる手段として開示されているが、充分な耐リーク性を得るには至っていない。
以上のように、特に、高流量で原料気体を通気した場合、基材同士の接触や基材とスペーサーとの接触、運転時における振動などで生じるイオン交換樹脂の剥離や水蒸気透過膜の摩耗に起因する、基材の耐圧強度低下、基材を介した差圧による原料気体のリークをも改善し、且つ、長期的に高い水蒸気透過性能を維持する水蒸気透過膜は存在しない。
However, in order to use a thin perfluorosulfonic acid ion exchange membrane alone, it must have a certain thickness in order to provide necessary mechanical strength and leakage resistance. For this reason, there is a limit to reducing the thickness of the water vapor permeable membrane.
In order to solve these problems, Patent Document 1 discloses a structure in which a moisture-permeable resin layer made of a perfluorosulfonic acid ion exchange resin cured on the surface is provided.
Patent Document 2 discloses an example in which a sulfonic acid ion exchange resin is applied to a polyethylene porous substrate hollow fiber and then dried.
However, although the water vapor permeable membranes using these ion exchange resins utilize the high water vapor permeability shown in the case where the counter ion is proton type, they have not yet obtained sufficient leak resistance. In addition, in humidifiers used in high-power fuel cells such as automobile fuel cells, it is necessary to ventilate a large amount of raw material air at a maximum of several thousand liters / minute, in which case it exists in the raw material air. The effect of the adsorbing substance to be noticeable becomes remarkable, and the water vapor transmission performance decreases with time. In addition, when the operating environment temperature increases, the structure of the ion exchange resin changes due to heat, the water content decreases, and the water vapor transmission performance decreases with time.
Patent Document 3 discloses a dehumidifying membrane using an ion exchange resin in which a counter ion of an ion exchange group is substituted with a metal. In this patent document, it is disclosed as a means for improving the pressure resistance of the base material while maintaining the dehumidifying performance, but it has not yet achieved sufficient leak resistance.
As mentioned above, especially when a raw material gas is ventilated at a high flow rate, it is difficult to remove the ion exchange resin or wear the water vapor permeable membrane caused by contact between substrates, contact between the substrate and spacer, vibration during operation, etc. There is no water vapor permeable membrane that improves the deterioration of the pressure resistance of the base material, the leakage of the raw material gas due to the differential pressure through the base material, and maintains high water vapor permeation performance in the long term.
即ち、本発明の課題は、次の４点を同時に満たす水蒸気透過膜を提供することにある。即ち、耐リーク性と耐摩耗性を持ち、かつ、水蒸気透過性能の経時的な変化を抑制し、かつ、高い水蒸気透過性能を示す水蒸気透過膜を提供することにある。 That is, an object of the present invention is to provide a water vapor permeable membrane that simultaneously satisfies the following four points. That is, an object of the present invention is to provide a water vapor permeable membrane that has leak resistance and wear resistance, suppresses a change in water vapor permeation performance over time, and exhibits high water vapor permeation performance.
本発明者らは、前記課題を解決すべく鋭意検討を重ねた結果、本発明を完成するに至った。即ち、本発明は以下の通りのものである。
（１）表面処理された多孔質基体の表面にイオン交換樹脂の層を有する複合化された水蒸気透過膜であって、該イオン交換樹脂中のイオン交換基の対イオンがアンモニウムイオン及び／又は金属イオンであることを特徴とする水蒸気透過膜。
（２）該表面処理が、コロナ処理又は、電子線照射処理の何れかから選ばれる処理であることを特徴とする上記（１）に記載の水蒸気透過膜。
（３）該イオン交換樹脂がパーフルオロスルホン酸系イオン交換樹脂であることを特徴とする上記（１）又は（２）に記載の水蒸気透過膜。
（４）該対イオンが１価または２価の金属イオンであることを特徴とする上記（１）〜（３）のいずれかに記載の水蒸気透過膜。
（５）該対イオンが、アルカリ金属イオンまたはアルカリ土類金属イオンの何れかから選択される金属イオンであることを特徴とする上記（１）〜（４）のいずれかに記載の水蒸気透過膜。
（６）該対イオンがカルシウムイオンであることを特徴とする上記（１）〜（５）のいずれかに記載の水蒸気透過膜。
（７）該多孔質基材表面にイオン交換樹脂の層を設けた後に、７０℃以上の温度で熱処理が施されて成ることを特徴とする上記（１）〜（６）のいずれかに記載の水蒸気透過膜。
（８）上記（１）〜（７）のいずれかに記載の水蒸気透過膜を用いて原料気体を加湿する燃料電池システム。
As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the present invention is as follows.
(1) A composite water vapor permeable membrane having an ion exchange resin layer on the surface of a surface-treated porous substrate, wherein a counter ion of an ion exchange group in the ion exchange resin is an ammonium ion and / or a metal A water vapor permeable membrane characterized by being ions.
(2) The water vapor permeable membrane as described in (1) above, wherein the surface treatment is a treatment selected from either a corona treatment or an electron beam irradiation treatment.
(3) The water vapor permeable membrane as described in (1) or (2) above, wherein the ion exchange resin is a perfluorosulfonic acid ion exchange resin.
(4) The water vapor permeable membrane according to any one of (1) to (3) above, wherein the counter ion is a monovalent or divalent metal ion.
(5) The water vapor permeable membrane as described in any one of (1) to (4) above, wherein the counter ion is a metal ion selected from either an alkali metal ion or an alkaline earth metal ion .
(6) The water vapor permeable membrane according to any one of (1) to (5), wherein the counter ion is calcium ion.
(7) The method according to any one of (1) to (6) above, wherein a heat treatment is performed at a temperature of 70 ° C. or higher after providing an ion exchange resin layer on the surface of the porous substrate. Water vapor permeable membrane.
(8) A fuel cell system that humidifies the raw material gas using the water vapor permeable membrane according to any one of (1) to (7).
本発明の水蒸気透過膜は、耐リーク性、耐摩耗性を併せ持ち、且つ、水蒸気透過膜の経時的な性能低下を抑制し、高い水蒸気透過性能を長時間運転でも維持可能になさしめた。 The water vapor permeable membrane of the present invention has both leak resistance and wear resistance, suppresses deterioration in performance of the water vapor permeable membrane over time, and maintains high water vapor permeable performance even during long-time operation.
以下、本発明の水蒸気透過膜について詳説する。
本発明の水蒸気透過膜に用いられるイオン交換樹脂としては、イオン交換基としてカルボン酸基やスルホン酸基を含むイオン交換基が挙げられるが、好適に用いられるものは、下記一般式（１）で表されるパーフルオロスルホン酸系イオン交換樹脂であり、更に好適に用いられるイオン交換樹脂は、下記一般式（２）で表される旭化成ケミカルズ社製、商品名：Aciplex−SSが好適に用いられる。
Examples of the ion exchange resin used in the water vapor permeable membrane of the present invention include an ion exchange group containing a carboxylic acid group or a sulfonic acid group as an ion exchange group, and preferably used is the following general formula (1). As the ion exchange resin represented by the following general formula (2), trade name: Aciplex-SS is preferably used. .
イオン交換樹脂のイオン交換容量ＥＷ（g/EQ）とは、１モルの対イオンを交換するのに必要となるイオン交換樹脂量を表す。イオン交換樹脂がパーフルオロスルホン酸系イオン交換樹脂の場合、対イオンが全てプロトンである場合、１モルのプロトンを非プロトンのイオンに交換するのに必要となるイオン交換樹脂量である。イオン交換容量は、イオン交換樹脂が一般に入手可能なものであれば既知である場合が多いが、未知である場合は次の方法で測定することができる。つまり、本発明の場合、単位面積当たりのイオン交換樹脂量Ｍ（g/ m2）である水蒸気透過膜をＡ（m2）採取し、硝酸溶液に２４時間浸漬して対イオンを一度全てプロトン化する。次に、蒸留水で洗浄後、別途用意した蒸留水に１時間浸漬する。その蒸留水にＫＣｌ溶液を添加し、遊離してきたプロトンを水酸化ナトリウムで滴定する。水酸化ナトリウムの滴定量から中和に要した水酸化ナトリウム量Ｎ(mol)を算出し、下記式〔１〕に従ってイオン交換容量を測定することができる。
ＥＷ（g/ＥＱ）＝Ｍ×Ａ／Ｎ ・・・〔１〕
イオン交換樹脂のイオン交換基量Ｘ（mol/ m2）とは、単位面積の水蒸気透過膜中に含まれるイオン交換基の量を表す。イオン交換樹脂がパーフルオロスルホン酸系イオン交換樹脂の場合、イオン交換容量ＥＷと単位面積当たりのイオン交換樹脂量Ｍ（g/ m2）と水蒸気透過膜面積Ａ（m2）から下記式〔２〕を用いて算出することができる。
Ｘ（mol/ m2）= Ｍ×Ａ／ＥＷ ・・・〔２〕
The ion exchange capacity EW (g / EQ) of the ion exchange resin represents the amount of ion exchange resin necessary for exchanging 1 mol of counter ions. When the ion exchange resin is a perfluorosulfonic acid type ion exchange resin, when the counter ions are all protons, the amount is the amount of ion exchange resin required to exchange 1 mol of protons with non-proton ions. The ion exchange capacity is often known as long as the ion exchange resin is generally available, but can be measured by the following method if unknown. That is, in the case of the present invention, A (m 2 ) of a water vapor permeable membrane having an ion exchange resin amount M (g / m 2 ) per unit area is sampled and immersed in a nitric acid solution for 24 hours so that all the counter ions are once protonated. Turn into. Next, after washing with distilled water, it is immersed in separately prepared distilled water for 1 hour. A KCl solution is added to the distilled water, and the liberated protons are titrated with sodium hydroxide. The sodium hydroxide amount N (mol) required for neutralization can be calculated from the titration amount of sodium hydroxide, and the ion exchange capacity can be measured according to the following formula [1].
EW (g / EQ) = M × A / N (1)
The ion exchange group amount X (mol / m 2 ) of the ion exchange resin represents the amount of ion exchange groups contained in the water vapor permeable membrane having a unit area. When the ion exchange resin is a perfluorosulfonic acid ion exchange resin, the following formula [2] is obtained from the ion exchange capacity EW, the ion exchange resin amount M (g / m 2 ) per unit area, and the water vapor permeable membrane area A (m 2 ). ] Can be used to calculate.
X (mol / m 2 ) = M × A / EW (2)
本発明では、イオン交換樹脂中のイオン交換基の対イオンの全て或いは一部をアンモニウムイオン及び／又は金属イオンであることを特徴とするが、対イオンとしては、１級アンモニウムイオン、２級アンモニウムイオン、３級アンモニウムイオン、４級アンモニウムイオン、カルシウムなどのアルカリ土類金属イオン、ナトリウムなどのアルカリ金属イオン、銅イオン、亜鉛イオン、アルミニウムイオン、鉄イオンなどが挙げられるが、中でも、特にイオン交換基に対して吸着力の強いカルシウムなどのアルカリ土類金属、ナトリウムなどのアルカリ金属が好ましい。
対イオンとしてのアンモニウムイオンや金属イオンによる置換量は、イオン交換樹脂中のイオン交換基量の５％以上１００％以下が好ましく、より好ましく２０％以上１００％以下である。アンモニウムイオンや金属イオンによる置換量が５％未満である場合、不純物の影響や熱などの影響も受けてパーフルオロスルホン酸系イオン交換樹脂の透湿性能は経時的に低下するが、アンモニウムイオンや金属イオンによる置換量が５％以上１００％以下である場合、初期の水蒸気透過性能は対イオンの影響で若干低下するが、アンモニウムイオンや金属イオンによる置換量が５％未満である場合と比較して、経時的な性能低下を抑制することができ、かつ水蒸気透過性能の低下量を抑制することができる。
イオン交換樹脂のイオン交換基の対イオンの定量方法としては、イオンクロマト法で測定する方法が挙げられる。具体的には、パーフルオロスルホン酸系イオン交換樹脂を用いた水蒸気透過膜で、対イオンがカルシウムイオンの場合には、該水蒸気透過膜を一定量採取し、硝酸溶液に浸漬し、４０℃下２４時間放置した後、硝酸溶液を採取し、イオンクロマトでカルシウムイオン量測定を行い、濃度が既知である数種のカルシウム水溶液の測定結果から作成される検量線と比較することで、単位面積当たりの該水蒸気透過膜中に含まれるカルシウム量が求められる。
In the present invention, all or part of the counter ion of the ion exchange group in the ion exchange resin is an ammonium ion and / or a metal ion, and the counter ion includes a primary ammonium ion and a secondary ammonium ion. Ions, tertiary ammonium ions, quaternary ammonium ions, alkaline earth metal ions such as calcium, alkali metal ions such as sodium, copper ions, zinc ions, aluminum ions, iron ions, etc. An alkaline earth metal such as calcium and an alkali metal such as sodium are preferred because of their strong adsorptive power to the group.
The substitution amount by ammonium ions or metal ions as counter ions is preferably 5% or more and 100% or less, more preferably 20% or more and 100% or less of the amount of ion exchange groups in the ion exchange resin. When the amount of substitution with ammonium ions or metal ions is less than 5%, the moisture permeability of perfluorosulfonic acid ion exchange resin is deteriorated over time due to the influence of impurities and heat, but ammonium ions and When the amount of substitution by metal ions is 5% or more and 100% or less, the initial water vapor permeation performance is slightly lowered due to the influence of counter ions, but compared with the case where the amount of substitution by ammonium ions or metal ions is less than 5%. Thus, it is possible to suppress a decrease in performance over time and to suppress a decrease in water vapor transmission performance.
Examples of the method for quantifying the counter ion of the ion exchange group of the ion exchange resin include a method of measuring by ion chromatography. Specifically, in the case of a water vapor permeable membrane using a perfluorosulfonic acid ion exchange resin and the counter ion is calcium ion, a certain amount of the water vapor permeable membrane is sampled and immersed in a nitric acid solution at 40 ° C. After leaving for 24 hours, a nitric acid solution is collected, the amount of calcium ions is measured by ion chromatography, and compared with a calibration curve created from the measurement results of several types of calcium aqueous solutions with known concentrations. The amount of calcium contained in the water vapor permeable membrane is determined.
本発明の水蒸気透過膜は、上記アンモニウムイオン及び／又は金属イオンをイオン交換基の対イオンとして有するイオン交換樹脂を多孔質基体の表面に有することを特徴とする。
そこで、次に本発明で用いることができる多孔質基体について説明する。
多孔質基体の材質は、多孔質である限り特に限定はされないが、ゼオライト、活性炭、シリカゲルなどの無機多孔質基体、ポリエチレン、ポリプロピレン、ポリスルホン、ポリフッ化ビニリデン、ポリアクリロニトリル、ポリカーボネイト、ポリテトラフルオロエチレン、ポリテトラフルオロエチレン／ヘキサフルオロエチレン共重合体、ポリエチレンテレフタレート（ＰＥＴ）、ポリエーテルエーテルケトン（ＰＥＥＫ）、ポリエーテルケトン（ＰＥＫ）等の高分子樹脂多孔質基体が挙げられる。耐熱性、耐薬品性、成膜性の点で特に好ましいのは、ポリエチレン、ポリプロピレン、ポリフッ化ビニリデン、ポリテトラフルオロエチレン、ポリエーテルエーテルケトン（ＰＥＥＫ）、ポリエーテルケトン（ＰＥＫ）の高分子樹脂多孔質基体である。
多孔質基体の形状は、微多孔膜、不織布、織布、織物、織物、ネットなどが挙げられるが、多孔質である限り特に限定されるものではない。
多孔質基体の孔径は、特に限定されるものではないが、０．００１μｍ以上１０μｍ以下が好ましく、より好ましくは０．００５以上５μｍ以下であり、更に好ましくは０．０１μｍ以上１μｍ以下である。孔径が０．００１μｍ未満であると多孔膜の製膜の困難さが増し、孔径が１０μｍを超えると、耐圧性を維持して気体が漏れないようにイオン交換樹脂を均一に多孔膜表層に存在させることが困難になる傾向がある。
The water vapor permeable membrane of the present invention has an ion exchange resin having the above ammonium ion and / or metal ion as a counter ion of an ion exchange group on the surface of a porous substrate.
Then, the porous substrate that can be used in the present invention will be described next.
The material of the porous substrate is not particularly limited as long as it is porous, but inorganic porous substrates such as zeolite, activated carbon, silica gel, polyethylene, polypropylene, polysulfone, polyvinylidene fluoride, polyacrylonitrile, polycarbonate, polytetrafluoroethylene, Examples thereof include polymer resin porous substrates such as polytetrafluoroethylene / hexafluoroethylene copolymer, polyethylene terephthalate (PET), polyether ether ketone (PEEK), and polyether ketone (PEK). Particularly preferred in terms of heat resistance, chemical resistance and film formability are porous polymer resins of polyethylene, polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, polyetheretherketone (PEEK), and polyetherketone (PEK). It is a quality substrate.
Examples of the shape of the porous substrate include a microporous film, a nonwoven fabric, a woven fabric, a woven fabric, a woven fabric, and a net, but are not particularly limited as long as it is porous.
The pore diameter of the porous substrate is not particularly limited, but is preferably 0.001 μm or more and 10 μm or less, more preferably 0.005 or more and 5 μm or less, and still more preferably 0.01 μm or more and 1 μm or less. When the pore size is less than 0.001 μm, the difficulty of forming a porous membrane increases. When the pore size exceeds 10 μm, the ion exchange resin is uniformly present on the surface of the porous membrane so as to maintain pressure resistance and prevent gas leakage. Tend to be difficult to do.
多孔質基体の気孔率は、特に限定されるものではないが、５％以上９０％以下が好ましく、気孔率の下限は１０％以上がより好ましく、２０％以上が更に好ましく、３０％以上がより更に好ましく、４０％以上が最も好ましい。気孔率が５％未満である場合は、透湿性能が低下し、気孔率が９０％を超えると多孔膜の強度が弱くなる傾向がある。
このような多孔質基体の形態としては、シート状のものと中空糸状のものが挙げられるが、シート状の場合、シートの厚さは１μｍ以上１０００μｍ以下が好ましく、より好ましくは５μｍ以上５００μｍ以下であり、更に好ましくは１０μ以上３００μｍ以下である。厚みが１μｍ未満である場合は、水蒸気透過速度は上昇するが機械的強度が低下する為、好ましくない。
多孔質基体が中空糸状である場合には、中空糸の内径は特に限定されるものではないが、０．１ｍｍ以上５ｍｍ以下が好ましく、より好ましくは０．５ｍｍ以上３ｍｍ以下である。内径が０．１ｍｍより小さいと、ガスを流した時の圧力損失が大きくなり余分な動力が必要となり効率が悪くなる傾向がある。内径が５ｍｍを超えると機械的強度が強い中空糸を作り難い傾向がある。また、中空糸の外径も特に限定されるものではないが、内径の１．１〜２倍のものが、強度と水蒸気透過性のバランスが優れていて好ましい。
また、本発明の多孔質基体は表面処理を行うことを特徴とする。表面処理としては、コロナ処理、電子線照射処理、プラズマ処理、放射線処理、界面活性剤の含浸、多孔質基体表面の親水性モノマーによるグラフトなどの親水化手法が挙げられる。これらの処理の中で、簡便性やコストの点から、コロナ処理や電子線照射処理が好適である。
これらの表面処理が施されたことは、「ＪＩＳ−Ｋ−６７６８」を参照し、表面処理前後における多孔質基体表面の濡れ試験を行うことで判断できる。表面処理前に対して、表面処理後の表面張力が高くなれば、表面処理の効果が発現していることとなる。
The porosity of the porous substrate is not particularly limited, but is preferably 5% or more and 90% or less, and the lower limit of the porosity is more preferably 10% or more, further preferably 20% or more, and more preferably 30% or more. More preferred is 40% or more. When the porosity is less than 5%, the moisture permeability performance decreases, and when the porosity exceeds 90%, the strength of the porous film tends to be weakened.
Examples of such a porous substrate include sheet-like and hollow fiber-like ones. In the case of sheet-like, the thickness of the sheet is preferably 1 μm or more and 1000 μm or less, more preferably 5 μm or more and 500 μm or less. More preferably, it is 10 μm or more and 300 μm or less. When the thickness is less than 1 μm, the water vapor transmission rate increases, but the mechanical strength decreases.
When the porous substrate has a hollow fiber shape, the inner diameter of the hollow fiber is not particularly limited, but is preferably 0.1 mm or more and 5 mm or less, and more preferably 0.5 mm or more and 3 mm or less. If the inner diameter is smaller than 0.1 mm, the pressure loss when the gas flows is increased, so that extra power is required and the efficiency tends to deteriorate. When the inner diameter exceeds 5 mm, it tends to be difficult to make a hollow fiber having high mechanical strength. Also, the outer diameter of the hollow fiber is not particularly limited, but a hollow fiber having a diameter of 1.1 to 2 times the inner diameter is preferable because it has an excellent balance between strength and water vapor permeability.
Further, the porous substrate of the present invention is characterized by performing a surface treatment. Examples of the surface treatment include hydrophilization techniques such as corona treatment, electron beam irradiation treatment, plasma treatment, radiation treatment, surfactant impregnation, and grafting with a hydrophilic monomer on the surface of the porous substrate. Among these treatments, corona treatment and electron beam irradiation treatment are preferable from the viewpoint of simplicity and cost.
Whether or not these surface treatments have been performed can be determined by referring to “JIS-K-6768” and performing a wetness test on the surface of the porous substrate before and after the surface treatment. If the surface tension after the surface treatment is higher than that before the surface treatment, the effect of the surface treatment is exhibited.
また、本発明の水蒸気透過膜は熱処理を行ったものでも構わない。熱処理温度は、７０℃以上が好ましい。より好ましくは８０℃以上、更に好ましくは９０℃以上、より更に好ましくは１００℃以上、最も好ましくは１２０℃以上である。熱処理温度が７０℃未満の場合には排出気体が凝縮した際に発生する水へのイオン交換樹脂の溶出が起きる可能性がある。また、イオン交換樹脂の高い膨潤性の為にイオン交換樹脂が脆くなり、加湿装置の内圧やスペーサーとの接触、原料気体や排出気体との接触によりイオン交換樹脂層の剥離が懸念される。熱処理温度の上限は、使用する多孔質基体の耐熱温度を超えなければ良いが、熱処理温度が高くなる程、若干ではあるが水蒸気透過性能の低下が起こることを考慮すると、熱処理温度は２００℃未満が好ましい。なお、熱履歴の確認は、熱処理温度が高くなるとイオン交換膜中の含水率が低下することを利用して、水蒸気透過膜のイオン交換樹脂部の含水率を測定することで確認することができる。
本発明の水蒸気透過膜は、アンモニウムイオン及び／又は金属イオンをイオン交換基の対イオンとしたイオン交換樹脂の層が多孔質基体の表面にコーティングされた構造を特徴とするが、イオン交換樹脂は多孔質基体の表面近傍の細孔に貫入していても構わない。イオン交換樹脂の一部が多孔質基体の細孔の一部に貫入することでアンカー効果を得ることが可能であり、その場合の密着性は極めて高いものとなる。
The water vapor permeable membrane of the present invention may be heat-treated. The heat treatment temperature is preferably 70 ° C. or higher. More preferably, it is 80 degreeC or more, More preferably, it is 90 degreeC or more, More preferably, it is 100 degreeC or more, Most preferably, it is 120 degreeC or more. When the heat treatment temperature is lower than 70 ° C., the ion exchange resin may be eluted into water generated when the exhaust gas is condensed. In addition, the ion exchange resin becomes brittle due to the high swellability of the ion exchange resin, and there is a concern about peeling of the ion exchange resin layer due to the internal pressure of the humidifier, contact with the spacer, contact with the raw material gas or exhaust gas. The upper limit of the heat treatment temperature should not exceed the heat resistance temperature of the porous substrate to be used, but the heat treatment temperature is less than 200 ° C. in consideration of the slight decrease in water vapor transmission performance as the heat treatment temperature increases. Is preferred. The heat history can be confirmed by measuring the moisture content of the ion exchange resin portion of the water vapor permeable membrane by utilizing the fact that the moisture content in the ion exchange membrane decreases as the heat treatment temperature increases. .
The water vapor permeable membrane of the present invention is characterized by a structure in which an ion exchange resin layer having ammonium ions and / or metal ions as counter ions of an ion exchange group is coated on the surface of a porous substrate. You may penetrate into the pores near the surface of the porous substrate. An anchor effect can be obtained by part of the ion exchange resin penetrating into part of the pores of the porous substrate, and the adhesion in that case is extremely high.
イオン交換樹脂層の厚みは特に限定されるものではないが、多孔質基体の厚みに対して、０．２％以上２０％以下が好ましく、さらに好ましくは０．３％以上１８％以下であり、より更に好ましくは０．５％以上１５％以下である。多孔質基体が中空糸の場合は、コーティング層は中空糸の外壁表面であっても、内壁表面の何れをコーティングしたものであっても構わない。当然、両面がコーティングされていても構わない。
多孔質基体の細孔内に貫入するイオン交換樹脂の量は、多孔膜の細孔の全部を充填させる量であっても、細孔の一部のみを充填させられる量でも構わないが、好ましくは多孔質基体の片面から貫通孔が存在しないことが好ましい。
本発明の水蒸気透過膜は特に、燃料電池の原料気体に適用するにあたっては、水蒸気透過膜の両側にある気体中の水蒸気のみを透過し、他の気体成分は透過させないようにする必要がある為、貫通孔は有さないのが好ましい。具体的には、気体の透過率は、「ＪＩＳ−Ｐ−８１１７」に示す透気度で１００００秒／１００ｃｃ以上が好ましく、より好ましくは１０００００秒／１００ｃｃ以上である。この１００００秒／１００ｃｃという値は、１００ｃｃの気体を透過させるために必要な時間が１００００秒以上であることを意味する。
The thickness of the ion exchange resin layer is not particularly limited, but is preferably 0.2% or more and 20% or less, more preferably 0.3% or more and 18% or less, with respect to the thickness of the porous substrate. More preferably, it is 0.5% or more and 15% or less. When the porous substrate is a hollow fiber, the coating layer may be either the outer wall surface of the hollow fiber or the inner wall surface coated. Of course, both sides may be coated.
The amount of the ion exchange resin that penetrates into the pores of the porous substrate may be an amount that fills all the pores of the porous membrane or an amount that can fill only a part of the pores. It is preferable that no through hole exists from one side of the porous substrate.
In particular, when the water vapor permeable membrane of the present invention is applied to a raw material gas of a fuel cell, it is necessary to transmit only water vapor in the gas on both sides of the water vapor permeable membrane and not to allow other gas components to permeate. It is preferable that there is no through hole. Specifically, the gas permeability is preferably 10,000 seconds / 100 cc or more, and more preferably 100,000 seconds / 100 cc or more in terms of the air permeability shown in “JIS-P-8117”. The value of 10,000 seconds / 100 cc means that the time required for permeating 100 cc of gas is 10,000 seconds or more.
次に、本発明の水蒸気透過膜の製造方法について説明する。
本発明の水蒸気透過膜は表面処理された多孔質基体の表面にイオン交換樹脂を有する構造であることを特徴とするが、多孔質基体の表面にイオン交換樹脂の層を設ける具体的な方法としては、特に限定されるものではないが、例えば、グラビアロール、リバースロール、ドクターロール、キスロールなどを用いたコーティング方法や、噴霧、浸漬、濾過などの方法、グラフト重合などが挙げられる。具体的には、目的の層の厚みを考慮し、目的の濃度になる量のイオン交換樹脂をアルコール／水混合溶液に投入してイオン交換樹脂含有塗工液を調製し、多孔質基体を含浸、あるいは上記ロールで塗布した後に連続的な乾燥工程に導入して水蒸気透過膜を作成する方法が簡便で好ましい。
本発明に用いられる水蒸気透過膜のイオン交換基の対イオンに、アンモニウムイオンや金属イオンを導入する方法は、例えば、対イオンとして予めアンモニウムイオンや金属イオンを導入したイオン交換樹脂含有塗工液の塗布を行う方法や、予め多孔質基体の表面にプロトン以外の対イオンを殆ど含まないイオン交換樹脂含有塗工液の塗布を行った後に、アンモニウムイオンや金属イオンを含む溶液に浸漬し、アンモニウムイオンや金属イオンを対イオンとして導入する方法が挙げられる。後者の場合、その工程は、乾燥工程前に行っても構わないし、乾燥工程後で行っても構わない。
Next, the method for producing the water vapor permeable membrane of the present invention will be described.
The water vapor permeable membrane of the present invention is characterized by having a structure having an ion exchange resin on the surface of a surface-treated porous substrate. As a specific method of providing an ion exchange resin layer on the surface of a porous substrate, Is not particularly limited, and examples thereof include a coating method using a gravure roll, a reverse roll, a doctor roll, a kiss roll, a method such as spraying, dipping, and filtration, and graft polymerization. Specifically, taking into account the thickness of the target layer, an ion exchange resin in an amount to achieve the target concentration is introduced into an alcohol / water mixed solution to prepare an ion exchange resin-containing coating solution, and impregnated with a porous substrate. Alternatively, a method of forming a water vapor permeable membrane by applying it with the above roll and then introducing it into a continuous drying process is preferred.
The method of introducing ammonium ions or metal ions into the counter ion of the ion exchange group of the water vapor permeable membrane used in the present invention is, for example, an ion exchange resin-containing coating solution in which ammonium ions or metal ions are previously introduced as counter ions. After applying a coating solution containing an ion exchange resin containing almost no counter ions other than protons on the surface of the porous substrate in advance, it is immersed in a solution containing ammonium ions or metal ions to obtain ammonium ions. And a method of introducing a metal ion as a counter ion. In the latter case, the step may be performed before the drying step or after the drying step.
表面処理工程は、イオン交換樹脂含有塗工液に多孔質基体を浸漬する前であれば、何れのタイミングで行っても構わないが、好ましくは、イオン交換樹脂含有塗工液に含浸する直前に、コロナ放電装置や電子線照射装置による表面処理工程を導入し、ロール状で連続的に処理できる工程である。
熱処理工程は、多孔質基体がイオン交換樹脂含有塗工液に含浸された後であれば、何れのタイミングでも構わないが、好ましくは、ロール状でイオン交換樹脂含有塗工液に含浸し、引き続き乾燥工程と熱処理工程に導入し、水蒸気透過膜を得る工程が簡便である。熱処理方法は、ロールをテンターで連続的に処理する方法が好ましいが、特にこれに限定されるものではない。
本発明の水蒸気透過膜は燃料電池の加湿部として用いると効果を奏するので、以下に本発明の水蒸気透過膜を加湿部に用いる燃料電池システムについて説明する。
以上述べた通りの水蒸気透過膜を用いて原料気体を加湿する燃料電池システムとしては、原料気体が導入される原料気体用流路と、電池部からの排出気体が導入される排出気体用流路と、これらの流路を分離する水蒸気透過膜から構成される加湿部を持つ燃料電池システムであり、自己加湿部方式の燃料電池システム、あるいは外部加湿部方式の燃料電池システムの何れでも構わない。
The surface treatment step may be performed at any timing as long as it is before immersing the porous substrate in the ion exchange resin-containing coating solution, but preferably, immediately before impregnating the ion exchange resin-containing coating solution. In this process, a surface treatment step using a corona discharge device or an electron beam irradiation device is introduced, and the treatment can be continuously performed in a roll shape.
The heat treatment step may be performed at any timing as long as the porous substrate is impregnated with the ion exchange resin-containing coating solution, but preferably, the ion-exchange resin-containing coating solution is impregnated in a roll shape, and subsequently The process of introducing the water vapor permeable membrane by introducing it into the drying process and the heat treatment process is simple. The heat treatment method is preferably a method in which a roll is continuously treated with a tenter, but is not particularly limited thereto.
Since the water vapor permeable membrane of the present invention is effective when used as a humidifying portion of a fuel cell, a fuel cell system using the water vapor permeable membrane of the present invention for the humidifying portion will be described below.
The fuel cell system for humidifying the raw material gas using the water vapor permeable membrane as described above includes a raw material gas flow channel into which the raw material gas is introduced, and an exhaust gas flow channel into which the exhaust gas from the battery unit is introduced. And a fuel cell system having a humidifying unit constituted by a water vapor permeable membrane separating these flow paths, and may be either a self-humidifying unit type fuel cell system or an external humidifying unit type fuel cell system.
以下、本発明の水蒸気透過膜について、実施例および比較例を用いて、より具体的に説明する。なお、実施例の結果一覧を表１に示し、比較例の結果一覧を表２に示した。
〔実施例１〕
多孔質基体として、膜厚１６μｍ、空隙率４０％のポリエチレン製微多孔膜（商品名：ハイポアＮ９４１６Ｇ、旭化成ケミカルズ社製）を用いて、大気雰囲気下でコロナ処理を施し、コロナ処理膜Ａを得た。コロナ処理の高周波電源は、春日電機（株）製のＡＧＩ−０２３を用い、電極は、春日電機（株）製の電極アルミ５型６山を用いた。コロナ処理電圧は、２６０Ｗであり、ライン速度は１０ｍ／ｍｉｎで行った。コロナ処理後に濡れ強度試験を行ったところ、親水性が上昇していることを確認した。
次に、パーフルオロスルホン酸系イオン交換樹脂溶液（商品名：Ａｃｉｐｌｅｘ−ＳＳ−９５０、旭化成ケミカルズ社製、イオン交換容量９５０ｇ／ＥＱ）に、上記のコロナ処理膜Ａを１０秒間浸漬してコーティングを行い、８０℃のオーブン中にて２時間乾燥させてパーフルオロスルホン酸系イオン交換樹脂を硬化させた。次に、得られた膜を０．１ｍｏｌ／ｌに調製された塩化カルシウム水溶液に２４時間浸漬後、蒸留水で水洗し、熱処理として、１２０℃のオーブン中にて２時間乾燥させて本発明の水蒸気透過膜Ａを得た。水蒸気透過膜Ａの厚みは１８μｍであった。
水蒸気透過膜Ａの単位面積当たり重量からコロナ処理膜Ａの単位面積当たり重量を引いて、コロナ処理膜Ａ上にコーティングされたパーフルオロスルホン酸系イオン交換樹脂の単位面積当たりの重量を求めたところ、４．５ｇ／ｍ2 であり、イオン交換樹脂の交換容量が９５０ｇ／ＥＱであることから、単位面積当たりのスルホン酸基量は４．７×１０-3ｍｏｌ／ｍ2 であった。
Hereinafter, the water vapor permeable membrane of the present invention will be described more specifically with reference to Examples and Comparative Examples. In addition, the result list of the examples is shown in Table 1, and the result list of the comparative examples is shown in Table 2.
[Example 1]
As a porous substrate, a microporous polyethylene film (trade name: Hypore N9416G, manufactured by Asahi Kasei Chemicals Corporation) having a film thickness of 16 μm and a porosity of 40% is subjected to corona treatment in an air atmosphere to obtain a corona-treated film A. It was. AGI-023 manufactured by Kasuga Electric Co., Ltd. was used as a high-frequency power source for corona treatment, and electrode aluminum 5 type 6 ridges manufactured by Kasuga Electric Co., Ltd. were used as electrodes. The corona treatment voltage was 260 W, and the line speed was 10 m / min. When the wet strength test was performed after the corona treatment, it was confirmed that the hydrophilicity was increased.
Next, the above corona-treated membrane A is dipped in a perfluorosulfonic acid ion exchange resin solution (trade name: Aciplex-SS-950, manufactured by Asahi Kasei Chemicals Corporation, ion exchange capacity 950 g / EQ) for 10 seconds for coating. And dried in an oven at 80 ° C. for 2 hours to cure the perfluorosulfonic acid ion exchange resin. Next, the obtained film was immersed in an aqueous solution of calcium chloride adjusted to 0.1 mol / l for 24 hours, washed with distilled water, and dried as a heat treatment in an oven at 120 ° C. for 2 hours. A water vapor permeable membrane A was obtained. The thickness of the water vapor permeable membrane A was 18 μm.
The weight per unit area of the perfluorosulfonic acid ion exchange resin coated on the corona-treated membrane A is determined by subtracting the weight per unit area of the corona-treated membrane A from the weight per unit area of the water vapor permeable membrane A. 4.5 g / m 2 and the exchange capacity of the ion exchange resin was 950 g / EQ, the amount of sulfonic acid groups per unit area was 4.7 × 10 −3 mol / m 2 .
次に、水蒸気透過膜Ａを２．５ｃｍ2 角に切断し、０．５ｍｍｏｌ／ｌの硝酸溶液に浸漬し、４０℃下２４時間放置した後、硝酸溶液を３０μｌ採取し、イオンクロマトでカルシウムイオンの定量を行った所、得られた水蒸気透過膜中に含まれるカルシウムイオンの単位面積当たりの量は２．２×１０-3ｍｏｌ／ｍ2 であり、スルホン酸基量に対する置換率は４６％であった。
次に、水蒸気透過膜Ａと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ａ１）の水蒸気透過性能を測定し、水蒸気透過性能の変化を調べた。水蒸気透過性能の測定方法は、ＪＩＳ−Ｌ−１０９９のＷＡＴＥＲ法に準じたが、測定環境温度は８０℃で行った。水蒸気透過性能の測定の結果、水蒸気透過膜Ａの水蒸気透過性能は１４５０ｇ／ｍ2 ／ｈであり、水蒸気透過膜Ａ１の水蒸気透過性能は１４５０ｇ／ｍ2 ／ｈであり、水蒸気透過性性能の低下率は０％であった。また、水蒸気透過膜Ａ１は変色しなかった。
次に、水蒸気透過膜Ａに設けられたイオン交換樹脂層と多孔質基体との接着性を調べた。試験方法は、過酷な運転条件に相当する次の方法を採用した。
即ち、得られた水蒸気透過膜Ａを約１０ｃｍ角に切断し、重量Ｗ１（ｍｇ）を測定した。
Next, the water vapor permeable membrane A was cut into 2.5 cm 2 squares, immersed in a 0.5 mmol / l nitric acid solution and allowed to stand at 40 ° C. for 24 hours. The amount of calcium ions contained in the water vapor permeable membrane per unit area was 2.2 × 10 −3 mol / m 2 , and the substitution rate relative to the amount of sulfonic acid groups was 46%. Met.
Next, the water vapor transmission performance of the water vapor transmission film A and the film (water vapor transmission film A1) left in an oven at 80 ° C. for 800 hours was measured, and changes in the water vapor transmission performance were examined. The method for measuring the water vapor transmission performance conformed to the WATER method of JIS-L-1099, but the measurement environment temperature was 80 ° C. As a result of the measurement of the water vapor transmission performance, the water vapor transmission performance of the water vapor transmission membrane A is 1450 g / m 2 / h, and the water vapor transmission performance of the water vapor transmission membrane A1 is 1450 g / m 2 / h. The rate was 0%. Further, the water vapor permeable membrane A1 was not discolored.
Next, the adhesion between the ion exchange resin layer provided on the water vapor permeable membrane A and the porous substrate was examined. As a test method, the following method corresponding to severe operating conditions was adopted.
That is, the obtained water vapor permeable membrane A was cut into about 10 cm square, and the weight W1 (mg) was measured.
次に、攪拌された８０℃の熱水中に３０分浸漬し、イオン交換樹脂を膨潤させた。その後、即座に回収し、約１０ｃｍ角に切断された１６メッシュのポリプロピレン製ネット（ＮＢＣ（株）製、商品名：網戸１８目）で挟み込み、更に、約１５ｃｍ角の平滑なステンレス板（厚み３ｍｍ）で挟み込み、平滑平面上で４０ｋPaの圧力を印加した。この操作を３回繰り返した後に、再度８０℃の熱水中に３０分浸漬して水蒸気透過膜Ａを回収し、乾燥後の重量Ｗ２（ｍｇ）を測定した。評価は、下記式〔３〕により計算される剥離率で行った。剥離率は０．１％であった。
剥離率（％）＝〔（Ｗ１−Ｗ２）／Ｗ１〕×１００ ・・・〔３〕
次に、得られた水蒸気透過膜Ａの透気量を測定した。本発明の水蒸気透過膜は、「ＪＩＳ−Ｐ−８１１７」に示す透気度では、実質的に１００００秒／１００ｃｃ以上になることが分かっているので、別途方法を採用した。具体的な方法は次の通りである。まず、得られた水蒸気透過膜を４７ｍｍΦに打ち抜き、支持体として金属メッシュを使用して、４７ｍｍカラム（ＡＤＶＡＮＴＥＣ製；ＫＳ−４７Ｆ）にセットした。次に、カラムの片側から４０ｋPaの空気を印加し、カラムの反対側から漏れ出る透気量Ｔ１（ｍｌ／ｍｉｎ）を測定した。次に、測定に用いた水蒸気透過膜Ａを攪拌された８０℃の熱水中に３０分浸漬し、イオン交換樹脂を膨潤させた。その後、即座に回収し、約１０ｃｍ角に切断された１６メッシュのポリプロピレン製ネット（ＮＢＣ（株）製、商品名：網戸１８目）で挟み込み、更に、約１５ｃｍ角の平滑なステンレス板（厚み３ｍｍ）で挟み込み、平滑平面上で３０ｋPaの圧力を印加した。この操作を３回繰り返した後に、水蒸気透過膜Ａを回収し、乾燥後、再び透気量の測定を行い、透気量Ｔ２（ｍｌ／ｍｉｎ）を得た。評価は、下記式〔４〕より計算される透気量変化度で行った所、透気量変化度は１．０であった。
透気量変化度＝Ｔ２／Ｔ１ ・・・〔４〕
Next, the ion exchange resin was swollen by immersing in stirred hot water at 80 ° C. for 30 minutes. After that, it was recovered immediately and sandwiched between 16 mesh polypropylene nets (trade name: screen door 18 made by NBC Co., Ltd.) cut into approximately 10 cm squares, and a smooth stainless steel plate of approximately 15 cm squares (thickness 3 mm) ) And a pressure of 40 kPa was applied on a smooth plane. After this operation was repeated three times, it was again immersed in hot water at 80 ° C. for 30 minutes to recover the water vapor permeable membrane A, and the weight W2 (mg) after drying was measured. Evaluation was performed by the peeling rate calculated by the following formula [3]. The peel rate was 0.1%.
Peeling rate (%) = [(W1-W2) / W1] × 100 (3)
Next, the air permeability of the obtained water vapor permeable membrane A was measured. The water vapor permeable membrane of the present invention has been known to have an air permeability of “JIS-P-8117” substantially equal to or greater than 10,000 seconds / 100 cc. The specific method is as follows. First, the obtained water vapor permeable membrane was punched out to 47 mmΦ, and set on a 47 mm column (manufactured by ADVANTEC; KS-47F) using a metal mesh as a support. Next, 40 kPa of air was applied from one side of the column, and the air permeability T1 (ml / min) leaking from the opposite side of the column was measured. Next, the water vapor permeable membrane A used for the measurement was immersed in a stirred 80 ° C. hot water for 30 minutes to swell the ion exchange resin. After that, it was recovered immediately and sandwiched between 16 mesh polypropylene nets (trade name: screen door 18 made by NBC Co., Ltd.) cut into approximately 10 cm squares, and a smooth stainless steel plate of approximately 15 cm squares (thickness 3 mm) ) And a pressure of 30 kPa was applied on a smooth plane. After repeating this operation three times, the water vapor permeable membrane A was recovered, dried, and then the air permeability was measured again to obtain the air permeability T2 (ml / min). The evaluation was performed with the degree of change in air permeability calculated from the following formula [4], and the degree of change in air permeability was 1.0.
Air permeability change rate = T2 / T1 [4]
次に、水蒸気透過膜Ａに設けられたイオン交換樹脂層の耐摩耗性を調べた。試験方法は、過酷な運転条件に相当する次の方法を採用した。即ち、得られた水蒸気透過膜Ａを約１０ｃｍ角に切断し、重量Ｗ３（ｍｇ）を測定した。次に、攪拌された８０℃の熱水中に３０分浸漬し、イオン交換樹脂を膨潤させた。その後、即座に回収し、平滑平面上に固定させた。次に、水蒸気透過膜上に前出の１６メッシュのポリプロピレン製ネットを巻きつけた１０ｃｍ角の平滑板を置き、さらに、その平滑板の上に１ｋｇの重りを乗せて静かに平滑板をスライドさせて水蒸気透過膜表面を払拭した。払拭操作は３回行った。払拭操作後、水蒸気透過膜を再度熱水に３０分浸漬した。この操作を３回繰り返した後に、水蒸気透過膜Ａを乾燥させて重量Ｗ４（ｍｇ）を測定した。耐摩耗性評価は、下記式〔５〕により計算される摩耗率で行った。摩耗率は０．２％であった。
摩耗率（％）＝〔（Ｗ３−Ｗ４）／Ｗ３〕×１００ ・・・〔５〕
以上の結果より、水蒸気透過膜Ａは、比較例と比べて、イオン交換樹脂の剥離も摩耗も殆ど見られず、透気量変化度も小さいことから、耐リーク性と耐摩耗性を有することがわかる。更に、水蒸気透過性能低下も無く、経時変化を抑制して高い水蒸気透過性能を発揮することが確認された。
Next, the wear resistance of the ion exchange resin layer provided on the water vapor permeable membrane A was examined. As a test method, the following method corresponding to severe operating conditions was adopted. That is, the obtained water vapor permeable membrane A was cut into about 10 cm square, and the weight W3 (mg) was measured. Next, the ion exchange resin was swollen by immersing in stirred hot water at 80 ° C. for 30 minutes. Then, it collect | recovered immediately and was made to fix on a smooth plane. Next, a 10 cm square smooth plate with the 16 mesh polypropylene net wrapped above is placed on the water vapor permeable membrane, and a 1 kg weight is placed on the smooth plate and the smooth plate is gently slid. The surface of the water vapor permeable membrane was wiped off. The wiping operation was performed three times. After the wiping operation, the water vapor permeable membrane was again immersed in hot water for 30 minutes. After repeating this operation three times, the water vapor permeable membrane A was dried and the weight W4 (mg) was measured. The wear resistance was evaluated based on the wear rate calculated by the following formula [5]. The wear rate was 0.2%.
Wear rate (%) = [(W3-W4) / W3] × 100 (5)
From the above results, the water vapor permeable membrane A has almost no peeling or wear of the ion exchange resin and the degree of change in the air permeability is small as compared with the comparative example, so that it has leak resistance and wear resistance. I understand. Further, it was confirmed that there was no decrease in water vapor transmission performance, and that high water vapor transmission performance was exhibited while suppressing changes over time.
〔実施例２〕
０．１ｍｏｌ／ｌの塩化カルシウムの代わりに０．１ｍｏｌ／ｌの塩化カリウムを用いた以外は実施例１と同様の方法を用いて、本発明の水蒸気透過膜Ｂを作成した。水蒸気透過膜Ｂの厚みは１８μｍであった。
実施例１と同様に、水蒸気透過膜Ｂに設けられたパーフルオロスルホン酸系イオン交換樹脂の単位面積当たりの重量を求めたところ、４．６ｇ／ｍ2 であり、単位面積当たりのスルホン酸基量は４．８×１０-3ｍｏｌ／ｍ2 であった。
次に、実施例１と同様に、得られた水蒸気透過膜中の単位面積当たりのカリウムイオン量を測定したところ、４．４×１０-3ｍｏｌ／ｍ2 であり、スルホン酸基量に対する置換率は９２％であった。
次に、実施例１と同様に、水蒸気透過膜Ｂと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ｂ１）の水蒸気透過性能を測定した結果、水蒸気透過膜Ｂの水蒸気透過性能は１４５０ｇ／ｍ2 ／ｈであり、水蒸気透過膜Ｂ１の水蒸気透過性能は１４３０ｇ／ｍ2 ／ｈであり、水蒸気透過性性能の低下率は１％であった。水蒸気透過膜Ｂ１は変色しなかった。
また、実施例１と同様に、水蒸気透過膜Ｂの剥離率と摩耗率と透気量変化度を測定したところ、剥離率が０．２％であり、摩耗率が０．２％であり、透気量変化量は１．０であった。
以上の結果より、水蒸気透過膜Ｂは、比較例と比べて、イオン交換樹脂の剥離も摩耗も殆ど見られず、透気量変化度も小さいことから、耐リーク性と耐摩耗性を有することがわかる。更に、水蒸気透過性能低下も殆ど無く、経時変化を抑制して高い水蒸気透過性能を発揮することが確認された。
[Example 2]
A water vapor permeable membrane B of the present invention was prepared in the same manner as in Example 1 except that 0.1 mol / l potassium chloride was used instead of 0.1 mol / l calcium chloride. The thickness of the water vapor permeable membrane B was 18 μm.
As in Example 1, the weight per unit area of the perfluorosulfonic acid ion exchange resin provided in the water vapor permeable membrane B was determined to be 4.6 g / m 2. The amount was 4.8 × 10 −3 mol / m 2 .
Next, when the amount of potassium ions per unit area in the obtained water vapor permeable membrane was measured in the same manner as in Example 1, it was 4.4 × 10 −3 mol / m 2 , and the substitution with respect to the amount of sulfonic acid group The rate was 92%.
Next, as in Example 1, the water vapor transmission performance of the water vapor transmission membrane B and the membrane (water vapor transmission membrane B1) that was left in an oven at 80 ° C. for 800 hours was measured. was 1450g / m 2 / h, the water vapor permeability of the water vapor permeable membrane B1 is 1430g / m 2 / h, rate of decrease in water vapor permeability performance was 1%. The water vapor permeable membrane B1 did not change color.
Further, as in Example 1, when the peel rate and wear rate of the water vapor permeable membrane B and the change in air permeability were measured, the peel rate was 0.2% and the wear rate was 0.2%. The amount of change in air permeability was 1.0.
From the above results, the water vapor permeable membrane B has almost no peeling or wear of the ion exchange resin and little change in air permeability, so that it has leak resistance and wear resistance. I understand. Furthermore, it was confirmed that there was almost no decrease in water vapor permeation performance, and high water vapor permeation performance was exhibited while suppressing changes over time.
〔実施例３〕
０．１ｍｏｌ／ｌの塩化カルシウム水溶液の代わりに０．１ｍｏｌ／ｌのアンモニア水溶液を用いる以外は実施例１と同様の方法を用いて、本発明の水蒸気透過膜Ｃを作成した。水蒸気透過膜Ｃの厚みは１８μｍであった。
実施例１と同様に、水蒸気透過膜Ｃに設けられたパーフルオロスルホン酸系イオン交換樹脂の単位面積当たりの重量を求めたところ、４．６ｇ／ｍ2 であり、単位面積当たりのスルホン酸基量は４．８×１０-3ｍｏｌ／ｍ2 であった。
次に、実施例１と同様に、得られた水蒸気透過膜中の単位面積当たりのアンモニウムイオン量を測定したところ、１．９×１０-3ｍｏｌ／ｍ2 であり、スルホン酸基量に対する置換率は４０％であった。
次に、実施例１と同様に、水蒸気透過膜Ｃと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ｃ）の水蒸気透過性能を測定した結果、水蒸気透過膜Ｃの水蒸気透過性能は１４５０ｇ／ｍ2 ／ｈであり、８０℃のオーブンにて８００時間放置した膜の水蒸気透過性能は１４４０ｇ／ｍ2 ／ｈであり、水蒸気透過性性能の低下率は１％であった。また、水蒸気透過膜Ｃ１は変色しなかった。
また、実施例１と同様に、水蒸気透過膜Ｃの剥離率と摩耗率と透気量変化度を測定したところ、剥離率が０．３％であり、摩耗率が０．３％であり、透気量変化量は１．０であった。
以上の結果より、水蒸気透過膜Ｃは、比較例と比べて、イオン交換樹脂の剥離も摩耗も殆ど見られず、透気量変化度も小さいことから、耐リーク性と耐摩耗性を有することがわかる。更に、水蒸気透過性能低下も殆ど無く、経時変化を抑制して高い水蒸気透過性能を発揮することが確認された。
Example 3
A water vapor permeable membrane C of the present invention was prepared in the same manner as in Example 1 except that a 0.1 mol / l aqueous ammonia solution was used instead of the 0.1 mol / l calcium chloride aqueous solution. The thickness of the water vapor permeable membrane C was 18 μm.
As in Example 1, the weight per unit area of the perfluorosulfonic acid ion exchange resin provided in the water vapor permeable membrane C was determined to be 4.6 g / m 2. The amount was 4.8 × 10 −3 mol / m 2 .
Next, when the amount of ammonium ions per unit area in the obtained water vapor permeable membrane was measured in the same manner as in Example 1, it was 1.9 × 10 −3 mol / m 2 , which was substituted for the amount of sulfonic acid groups. The rate was 40%.
Next, as in Example 1, the water vapor transmission performance of the water vapor transmission membrane C and the water vapor transmission performance of the membrane (water vapor transmission membrane C) that was left in an oven at 80 ° C. for 800 hours was measured. It was 1450 g / m 2 / h, the water vapor transmission performance of the film left in an oven at 80 ° C. for 800 hours was 1440 g / m 2 / h, and the rate of decrease in water vapor transmission performance was 1%. Further, the water vapor permeable membrane C1 was not discolored.
Further, as in Example 1, when the peel rate and wear rate of the water vapor permeable membrane C and the change in air permeability were measured, the peel rate was 0.3% and the wear rate was 0.3%. The amount of change in air permeability was 1.0.
From the above results, the water vapor permeable membrane C has almost no peeling or wear of the ion exchange resin and little change in air permeability, and therefore has leak resistance and wear resistance, as compared with the comparative example. I understand. Furthermore, it was confirmed that there was almost no decrease in water vapor permeation performance, and high water vapor permeation performance was exhibited while suppressing changes over time.
〔実施例４〕
パーフルオロスルホン酸系イオン交換樹脂溶液（商品名：Ａｃｉｐｌｅｘ−ＳＳ−９５０、旭化成ケミカルズ社製）に、溶液中に含まれるスルホン酸基モル量と同モル量の塩化カリウムを溶解させ、実施例１と同様にポリエチレン製微多孔膜を１０秒間浸漬させてコーティングを行い、１２０℃のオーブン中にて２時間乾燥させてパーフルオロスルホン酸系イオン交換樹脂を硬化させて、本発明の水蒸気透過膜Ｄを得た。水蒸気透過膜Ｄの厚みは１８μｍであった。
実施例１と同様に、水蒸気透過膜Ｄに設けられたパーフルオロスルホン酸系イオン交換樹脂の単位面積当たりの重量を求めたところ、４．８ｇ／ｍ2 であり、単位面積当たりのスルホン酸基量は５．１×１０-3ｍｏｌ／ｍ2 であった。
次に、実施例１と同様に、得られた水蒸気透過膜中の単位面積当たりのカリウムイオン量を測定したところ、５．１×１０-3ｍｏｌ／ｍ2 であり、スルホン酸基量に対する置換率は１００％であった。
次に、実施例１と同様に、水蒸気透過膜Ｄと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ｄ）の水蒸気透過性能を測定した結果、水蒸気透過膜Ｄの水蒸気透過性能は１４４０ｇ／ｍ2 ／ｈであり、８０℃のオーブンにて８００時間放置した膜の水蒸気透過性能は１４３０ｇ／ｍ2 ／ｈであり、水蒸気透過性性能の低下率は１％であった。また、水蒸気透過膜Ｄ１は変色しなかった。
また、実施例１と同様に、水蒸気透過膜Ｄの剥離率と摩耗率と透気量変化度を測定したところ、剥離率が０．２％であり、摩耗率が０．３％であり、透気量変化量は１．０であった。
以上の結果より、水蒸気透過膜Ｄは、比較例と比べて、イオン交換樹脂の剥離も摩耗も殆ど見られず、透気量変化度も小さいことから、耐リーク性と耐摩耗性を有することがわかる。更に、水蒸気透過性能低下も殆ど無く、経時変化を抑制して高い水蒸気透過性能を発揮することが確認された。
Example 4
Example 1 A potassium fluoride having the same molar amount as the sulfonic acid group molar amount contained in the solution was dissolved in a perfluorosulfonic acid ion exchange resin solution (trade name: Aciplex-SS-950, manufactured by Asahi Kasei Chemicals Corporation). In the same manner as above, the microporous membrane made of polyethylene is immersed for 10 seconds for coating, dried in an oven at 120 ° C. for 2 hours to cure the perfluorosulfonic acid ion exchange resin, and the water vapor permeable membrane D of the present invention. Got. The thickness of the water vapor permeable membrane D was 18 μm.
As in Example 1, the weight per unit area of the perfluorosulfonic acid ion exchange resin provided in the water vapor permeable membrane D was 4.8 g / m 2 , and the sulfonic acid group per unit area was found to be 4.8 g / m 2. The amount was 5.1 × 10 −3 mol / m 2 .
Next, when the amount of potassium ions per unit area in the obtained water vapor permeable membrane was measured in the same manner as in Example 1, it was 5.1 × 10 −3 mol / m 2 , which was substituted for the amount of sulfonic acid group. The rate was 100%.
Next, as in Example 1, the water vapor transmission performance of the water vapor transmission membrane D and the water vapor transmission performance of the membrane (water vapor transmission membrane D) that was left in an oven at 80 ° C. for 800 hours were measured. It was 1440 g / m 2 / h, the water vapor transmission performance of the film left in an oven at 80 ° C. for 800 hours was 1430 g / m 2 / h, and the rate of decrease in water vapor transmission performance was 1%. Further, the water vapor permeable membrane D1 was not discolored.
Further, as in Example 1, when the peel rate, wear rate, and air permeability change rate of the water vapor permeable membrane D were measured, the peel rate was 0.2%, and the wear rate was 0.3%. The amount of change in air permeability was 1.0.
From the above results, the water vapor permeable membrane D has almost no peeling or wear of the ion exchange resin and little change in air permeability, so that it has leak resistance and wear resistance. I understand. Furthermore, it was confirmed that there was almost no decrease in water vapor permeation performance, and high water vapor permeation performance was exhibited while suppressing changes over time.
〔実施例５〕
パーフルオロスルホン酸系イオン交換樹脂溶液（商品名：Ａｃｉｐｌｅｘ−ＳＳ−９５０、旭化成ケミカルズ社製）に、溶液中に含まれるスルホン酸基モル量に対して２０％モル量に相当する塩化カルシウムを溶解させ、実施例１と同様にポリエチレン製微多孔膜を１０秒間浸漬させてコーティングを行い、１２０℃のオーブン中にて２時間乾燥させてパーフルオロスルホン酸系イオン交換樹脂を硬化させて、本発明の水蒸気透過膜Ｅを得た。水蒸気透過膜Ｅの厚みは１８μｍであった。
実施例１と同様に、水蒸気透過膜Ｅに設けられたパーフルオロスルホン酸系イオン交換樹脂の単位面積当たりの重量を求めたところ、４．８ｇ／ｍ2 であり、単位面積当たりのスルホン酸基量は５．１×１０-3ｍｏｌ／ｍ2 であった。
次に、実施例１と同様に、得られた水蒸気透過膜中の単位面積当たりのカルシウムイオン量を測定したところ、１．０×１０-3ｍｏｌ／ｍ2 であり、スルホン酸基量に対する置換率は２０％であった。
次に、実施例１と同様に、水蒸気透過膜Ｅと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ｅ１）の水蒸気透過性能を測定した結果、水蒸気透過膜Ｅの水蒸気透過性能は１４５０ｇ／ｍ2 ／ｈであり、水蒸気透過膜Ｅ１の水蒸気透過性能は１４２０ｇ／ｍ2 ／ｈであり、水蒸気透過性性能の低下率は２％であった。また、水蒸気透過膜Ｅ１は変色しなかった。
また、実施例１と同様に、水蒸気透過膜Ｅの剥離率と摩耗率と透気量変化度を測定したところ、剥離率が０．２％であり、摩耗率が０．２％であり、透気量変化量は１．０であった。
以上の結果より、水蒸気透過膜Ｅは、比較例と比べて、イオン交換樹脂の剥離も摩耗も殆ど見られず、透気量変化度も小さいことから、耐リーク性と耐摩耗性を有することがわかる。更に、水蒸気透過性能低下も殆ど無く、経時変化を抑制して高い水蒸気透過性能を発揮することが確認された。
Example 5
In a perfluorosulfonic acid ion exchange resin solution (trade name: Aciplex-SS-950, manufactured by Asahi Kasei Chemicals Corporation), calcium chloride corresponding to 20% molar amount of sulfonic acid group molar amount contained in the solution is dissolved. In the same manner as in Example 1, a polyethylene microporous membrane was dipped for 10 seconds for coating, dried in an oven at 120 ° C. for 2 hours to cure the perfluorosulfonic acid ion exchange resin, and the present invention. The water vapor permeable membrane E was obtained. The thickness of the water vapor permeable membrane E was 18 μm.
As in Example 1, the weight per unit area of the perfluorosulfonic acid ion exchange resin provided in the water vapor permeable membrane E was 4.8 g / m 2 , and the sulfonic acid group per unit area was The amount was 5.1 × 10 −3 mol / m 2 .
Next, when the amount of calcium ions per unit area in the obtained water vapor permeable membrane was measured in the same manner as in Example 1, it was 1.0 × 10 −3 mol / m 2 , which was substituted for the amount of sulfonic acid group. The rate was 20%.
Next, as in Example 1, the water vapor transmission performance of the water vapor transmission membrane E and the water vapor transmission performance of the membrane (water vapor transmission membrane E1) left in an oven at 80 ° C. for 800 hours was measured. It was 1450 g / m 2 / h, the water vapor transmission performance of the water vapor permeable membrane E1 was 1420 g / m 2 / h, and the rate of decrease in the water vapor transmission performance was 2%. Further, the water vapor permeable membrane E1 was not discolored.
Further, as in Example 1, when the peel rate, wear rate, and air permeability change rate of the water vapor permeable membrane E were measured, the peel rate was 0.2%, and the wear rate was 0.2%. The amount of change in air permeability was 1.0.
From the above results, the water vapor permeable membrane E has almost no peeling or wear of the ion exchange resin, and the degree of change in the air permeability is small as compared with the comparative example, and therefore has the leak resistance and the wear resistance. I understand. Furthermore, it was confirmed that there was almost no decrease in water vapor permeation performance, and high water vapor permeation performance was exhibited while suppressing changes over time.
〔実施例６〕
多孔質基体の表面処理方法として、電子線照射処理（岩崎電気製；ＣＢ２５０、加速電圧：２５０ｋＶ、照射線量２５０ｋＧｙ）で行った以外は実施例１と同様の方法を用いて、対イオン置換率４６％の本発明の水蒸気透過膜Ｆを得た。水蒸気透過膜Ｆの厚みは１８μｍであった。得られた水蒸気透過膜Ｆと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ｆ１）の水蒸気透過性能を測定した結果、水蒸気透過膜Ｆの水蒸気透過性能は１４５０ｇ／ｍ2 ／ｈであり、水蒸気透過膜Ｆ１の水蒸気透過性能は１４２０ｇ／ｍ2 ／ｈであり、水蒸気透過性能の低下率は２％であった。また、水蒸気透過膜Ｆ１は変色しなかった。
また、実施例１と同様に、水蒸気透過膜Ｆの剥離率と摩耗率と透気量変化度を測定したところ、剥離率が０．３％であり、摩耗率が０．４％であり、透気量変化量は１．３であった。
以上の結果より、水蒸気透過膜Ｆは、比較例と比べて、イオン交換樹脂の剥離も摩耗も殆ど見られず、透気量変化度も小さいことから、耐リーク性と耐摩耗性を有することがわかる。更に、水蒸気透過性能低下も殆ど無く、経時変化を抑制して高い水蒸気透過性能を発揮することが確認された。
Example 6
As the surface treatment method for the porous substrate, the counter ion substitution rate was 46 using the same method as in Example 1 except that the surface treatment was performed by electron beam irradiation treatment (manufactured by Iwasaki Electric; CB250, acceleration voltage: 250 kV, irradiation dose 250 kGy). % Of the water vapor permeable membrane F of the present invention was obtained. The thickness of the water vapor permeable membrane F was 18 μm. As a result of measuring the water vapor transmission performance of the obtained water vapor transmission membrane F and the membrane (water vapor transmission membrane F1) left in an oven at 80 ° C. for 800 hours, the water vapor transmission performance of the water vapor transmission membrane F is 1450 g / m 2 / h. Yes, the water vapor transmission performance of the water vapor transmission membrane F1 was 1420 g / m 2 / h, and the reduction rate of the water vapor transmission performance was 2%. Further, the water vapor permeable membrane F1 was not discolored.
Further, as in Example 1, when the peel rate and wear rate of the water vapor permeable membrane F and the degree of change in air permeability were measured, the peel rate was 0.3% and the wear rate was 0.4%. The amount of change in air permeability was 1.3.
From the above results, the water vapor permeable membrane F has almost no peeling or wear of the ion exchange resin and little change in air permeability, so that it has leak resistance and wear resistance. I understand. Furthermore, it was confirmed that there was almost no decrease in water vapor permeation performance, and high water vapor permeation performance was exhibited while suppressing changes over time.
〔実施例７〕
水蒸気透過膜に熱処理を施さない以外は実施例１と同様の方法を用いて、対イオン置換率４７％の本発明の水蒸気透過膜Ｇを得た。水蒸気透過膜Ｇの厚みは１８μｍであった。得られた水蒸気透過膜Ｇと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ｇ１）の水蒸気透過性能を測定した結果、水蒸気透過膜Ｇの水蒸気透過性能は１４６０ｇ／ｍ2 ／ｈであり、水蒸気透過膜Ｇ１の水蒸気透過性能は１４３０ｇ／ｍ2 ／ｈであり、水蒸気透過性能の低下率は２％であった。また、水蒸気透過膜Ｇ１は変色しなかった。
また、実施例１と同様に、水蒸気透過膜Ｇの剥離率と摩耗率と透気量変化度を測定したところ、剥離率が１．１％であり、摩耗率が１．０％であり、透気量変化量は１．２であった。
以上の結果より、水蒸気透過膜Ｇは、比較例と比べて、イオン交換樹脂の剥離も摩耗も殆ど見られず、透気量変化度も小さいことから、耐リーク性と耐摩耗性を有することがわかる。更に、水蒸気透過性能低下も殆ど無く、経時変化を抑制して高い水蒸気透過性能を発揮することが確認された。
Example 7
A water vapor permeable membrane G of the present invention having a counter ion substitution rate of 47% was obtained using the same method as in Example 1 except that the water vapor permeable membrane was not subjected to heat treatment. The thickness of the water vapor permeable membrane G was 18 μm. As a result of measuring the water vapor transmission performance of the obtained water vapor transmission film G and the film (water vapor transmission film G1) left in an oven at 80 ° C. for 800 hours, the water vapor transmission performance of the water vapor transmission film G is 1460 g / m 2 / h. Yes, the water vapor transmission performance of the water vapor transmission membrane G1 was 1430 g / m 2 / h, and the reduction rate of the water vapor transmission performance was 2%. Further, the water vapor permeable membrane G1 was not discolored.
Further, as in Example 1, when the peel rate, wear rate, and air permeability change rate of the water vapor permeable membrane G were measured, the peel rate was 1.1%, and the wear rate was 1.0%. The amount of change in air permeability was 1.2.
From the above results, the water vapor permeable membrane G has leakage resistance and wear resistance because there is almost no peeling or wear of the ion exchange resin and the degree of change in air permeability is small compared to the comparative example. I understand. Furthermore, it was confirmed that there was almost no decrease in water vapor permeation performance, and high water vapor permeation performance was exhibited while suppressing changes over time.
〔比較例１〕
パーフルオロスルホン酸系イオン交換樹脂溶液（商品名：Ａｃｉｐｌｅｘ−ＳＳ−９５０、旭化成ケミカルズ社製）に、表面処理が施されていないポリエチレン製微多孔膜を１０秒間浸漬させてコーティングを行い、室温で２時間乾燥させてパーフルオロスルホン酸系イオン交換樹脂を硬化させて水蒸気透過膜Ｗを得た。水蒸気透過膜Ｗの厚みは１８μｍであった。
実施例１と同様に、パーフルオロスルホン酸系イオン交換樹脂の単位面積当たりの重量を求めたところ４．５ｇ／ｍ2 であり、イオン交換樹脂の交換容量が９５０ｇ／ＥＱであることから単位面積当たりのスルホン酸基量は、４．７×１０-3ｍｏｌ／ｍ2 であった。
次に、水蒸気透過膜Ｗを実施例１と同様に、イオンクロマトでカルシウムイオンの定量を行ったところ、水蒸気透過膜Ｗに含まれるカルシウムイオンの単位面積当たりの量は０ｍｏｌ／ｍ2 であり、スルホン酸基量に対する置換率は０％であった。
次に、実施例１同様に、水蒸気透過膜Ｗと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ｗ１）の水蒸気透過性能を測定し、水蒸気透過性能の変化を調べた結果、水蒸気透過膜Ｗの水蒸気透過性能は１６５０ｇ／ｍ2 ／ｈであり、水蒸気透過膜Ｗ１の水蒸気透過性能は１２５０ｇ／ｍ2 ／ｈであり、水蒸気透過性性能の低下率は約２４％であった。また、水蒸気透過膜Ｗ１は茶色に変色した。
また、実施例１と同様に、水蒸気透過膜Ｗの剥離率と摩耗率と透気量変化度を測定したところ、剥離率が２．０％であり、摩耗率が４．３％であり、透気量変化量は１０であった。
[Comparative Example 1]
A perfluorosulfonic acid ion exchange resin solution (trade name: Aciplex-SS-950, manufactured by Asahi Kasei Chemicals Corporation) is coated by immersing a polyethylene microporous membrane that has not been surface-treated for 10 seconds at room temperature. By drying for 2 hours, the perfluorosulfonic acid ion exchange resin was cured to obtain a water vapor permeable membrane W. The thickness of the water vapor permeable membrane W was 18 μm.
As in Example 1, the weight per unit area of the perfluorosulfonic acid ion exchange resin was 4.5 g / m 2 , and the exchange capacity of the ion exchange resin was 950 g / EQ. The amount of sulfonic acid groups per unit was 4.7 × 10 −3 mol / m 2 .
Next, when the water vapor permeable membrane W was quantified with ion chromatography in the same manner as in Example 1, the amount of calcium ions contained in the water vapor permeable membrane W per unit area was 0 mol / m 2 . The substitution rate with respect to the amount of sulfonic acid group was 0%.
Next, as in Example 1, the water vapor transmission performance of the water vapor transmission membrane W and the membrane (water vapor transmission membrane W1) left in an oven at 80 ° C. for 800 hours was measured, and the change in the water vapor transmission performance was examined. The water vapor transmission performance of the permeable membrane W was 1650 g / m 2 / h, the water vapor transmission performance of the water vapor permeable membrane W1 was 1250 g / m 2 / h, and the rate of decrease in the water vapor transmission performance was about 24%. In addition, the water vapor permeable membrane W1 turned brown.
Further, as in Example 1, when the peel rate, wear rate, and air permeability change rate of the water vapor permeable membrane W were measured, the peel rate was 2.0%, and the wear rate was 4.3%. The amount of change in air permeability was 10.
〔比較例２〕
多孔質基体の表面処理と熱処理を施さないこと以外は実施例１と同様の方法で水蒸気透過膜を作成し、対イオン置換率４５％の水蒸気透過膜Ｘを得た。水蒸気透過膜Ｘの膜厚は１８μｍであった。得られた水蒸気透過膜Ｘと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ｘ１）の水蒸気透過性能を測定した結果、水蒸気透過膜Ｘの水蒸気透過性能は１４４０ｇ／ｍ2 ／ｈであり、水蒸気透過膜Ｘ１の水蒸気透過性能は１４４０ｇ／m2／ｈであり、水蒸気透過性能の低下率は０％であった。また、水蒸気透過膜Ｘ１は変色しなかった。
また、実施例１と同様に、水蒸気透過膜Ｘの剥離率と摩耗率と透気量変化度を測定したところ、剥離率が２．５％であり、摩耗率が５．０％であり、透気量変化量は１５であった。
[Comparative Example 2]
A water vapor permeable membrane was prepared in the same manner as in Example 1 except that the surface treatment and heat treatment of the porous substrate were not performed, and a water vapor permeable membrane X having a counter ion substitution rate of 45% was obtained. The film thickness of the water vapor permeable membrane X was 18 μm. As a result of measuring the water vapor transmission performance of the obtained water vapor transmission membrane X and the membrane (water vapor transmission membrane X1) left in an oven at 80 ° C. for 800 hours, the water vapor transmission performance of the water vapor transmission membrane X is 1440 g / m 2 / h. Yes, the water vapor transmission performance of the water vapor transmission membrane X1 was 1440 g / m 2 / h, and the rate of decrease in the water vapor transmission performance was 0%. Further, the water vapor permeable membrane X1 was not discolored.
Further, as in Example 1, when the peel rate, wear rate, and air permeability change rate of the water vapor permeable membrane X were measured, the peel rate was 2.5%, and the wear rate was 5.0%. The amount of change in air permeability was 15.
〔比較例３〕
塩化カルシウム水溶液への浸漬と熱処理を施さないこと以外は実施例１と同様の方法で水蒸気透過膜を作成し、水蒸気透過膜Ｙを得た。水蒸気透過膜Ｙの膜厚は１８μｍであった。得られた水蒸気透過膜Ｙと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ｙ１）の水蒸気透過性能を測定した結果、水蒸気透過膜Ｙの水蒸気透過性能は１６４０ｇ／ｍ2 ／ｈであり、水蒸気透過膜Ｙ１の水蒸気透過性能は１２６０ｇ／ｍ2 ／ｈであり、水蒸気透過性能の低下率は２３％であった。また、水蒸気透過膜Ｙ１は茶変した。
また、実施例１と同様に、水蒸気透過膜Ｙの剥離率と摩耗率と透気量変化度を測定したところ、剥離率が１．８％であり、摩耗率が４．０％であり、透気量変化量は２．５であった。
〔比較例４〕
多孔質基体の表面処理と塩化カルシウム水溶液への浸漬を施さないこと以外は実施例１と同様の方法で水蒸気透過膜を作成し、水蒸気透過膜Ｚを得た。水蒸気透過膜Ｚの膜厚は１８μｍであった。得られた水蒸気透過膜Ｚと、８０℃のオーブンに８００時間放置した膜（水蒸気透過膜Ｚ１）の水蒸気透過性能を測定した結果、水蒸気透過膜Ｚの水蒸気透過性能は１６００ｇ／ｍ2 ／ｈであり、水蒸気透過膜Ｚ１の水蒸気透過性能は１２７０ｇ／ｍ2 ／ｈであり、水蒸気透過性能の低下率は２１％であった。また、水蒸気透過膜Ｚは薄茶色を呈し、水蒸気透過膜Ｚ１は茶色を呈した。
また、実施例１と同様に、水蒸気透過膜Ｚの剥離率と摩耗率と透気量変化度を測定したところ、剥離率が２．５％であり、摩耗率が３．０％であり、透気量変化量は１４であった。
[Comparative Example 3]
A water vapor permeable membrane Y was obtained in the same manner as in Example 1 except that it was immersed in an aqueous calcium chloride solution and not subjected to heat treatment. The film thickness of the water vapor permeable membrane Y was 18 μm. As a result of measuring the water vapor transmission performance of the obtained water vapor transmission film Y and the film (water vapor transmission film Y1) left in an oven at 80 ° C. for 800 hours, the water vapor transmission performance of the water vapor transmission film Y is 1640 g / m 2 / h. The water vapor transmission performance of the water vapor transmission membrane Y1 was 1260 g / m 2 / h, and the rate of decrease in the water vapor transmission performance was 23%. In addition, the water vapor permeable membrane Y1 changed to brown.
Further, as in Example 1, when the peel rate, wear rate, and air permeability change rate of the water vapor permeable membrane Y were measured, the peel rate was 1.8%, and the wear rate was 4.0%. The amount of change in air permeability was 2.5.
[Comparative Example 4]
A water vapor permeable membrane Z was obtained in the same manner as in Example 1 except that the porous substrate was not surface-treated and immersed in an aqueous calcium chloride solution. The film thickness of the water vapor permeable membrane Z was 18 μm. As a result of measuring the water vapor transmission performance of the obtained water vapor transmission membrane Z and the membrane (water vapor transmission membrane Z1) left in an oven at 80 ° C. for 800 hours, the water vapor transmission performance of the water vapor transmission membrane Z is 1600 g / m 2 / h. Yes, the water vapor transmission performance of the water vapor transmission membrane Z1 was 1270 g / m 2 / h, and the reduction rate of the water vapor transmission performance was 21%. Further, the water vapor permeable film Z was light brown and the water vapor permeable film Z1 was brown.
Further, as in Example 1, when the peel rate and wear rate of the water vapor permeable membrane Z and the change in air permeability were measured, the peel rate was 2.5% and the wear rate was 3.0%. The amount of change in air permeability was 14.
本発明の水蒸気透過膜は、水蒸気透過膜の経時的な性能低下が小さい為、加湿部に要求される水蒸気透過性能を考慮したデザイン設計が容易になり、更に、長時間運転した際の水蒸気透過性能が向上する為、加湿部に要求される水蒸気透過性能を発揮する為に必要となるサイズを減少させ、コストパフォーマンスに優れた燃料電池システムを提供することが可能である。また、耐リーク性と耐摩耗性も向上する為、加湿部に求められる長期安定性を保証する製品を提供することが可能である。 The water vapor permeable membrane of the present invention has a small performance deterioration over time of the water vapor permeable membrane, so that the design design considering the water vapor permeation performance required for the humidifying part is easy, and further the water vapor permeation when operated for a long time. Since the performance is improved, it is possible to provide a fuel cell system excellent in cost performance by reducing the size required to exhibit the water vapor permeation performance required for the humidifying section. In addition, since leakage resistance and wear resistance are improved, it is possible to provide a product that guarantees long-term stability required for the humidified portion.
Claims (8)
A fuel cell system for humidifying a raw material gas using the water vapor permeable membrane according to claim 1.
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| JP2005006046A JP2006192364A (en) | 2005-01-13 | 2005-01-13 | Vapor permeable membrane |
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| JP2005006046A JP2006192364A (en) | 2005-01-13 | 2005-01-13 | Vapor permeable membrane |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61187918A (en) * | 1985-02-18 | 1986-08-21 | Asahi Chem Ind Co Ltd | Dry etching method |
| JPS627417A (en) * | 1985-02-09 | 1987-01-14 | Asahi Chem Ind Co Ltd | Semipermeable polymer membrane for drying gas to high degree and gas drying method using the same |
| JPH02293551A (en) * | 1989-05-09 | 1990-12-04 | Asahi Glass Co Ltd | Humidifying method |
| JPH07275637A (en) * | 1994-04-08 | 1995-10-24 | Asahi Glass Co Ltd | Dehumidification method |
| JP2001313057A (en) * | 2000-04-27 | 2001-11-09 | Asahi Glass Co Ltd | Manufacturing method of ion-exchange filter for solid polymer fuel cell |
| JP2002117878A (en) * | 2000-10-05 | 2002-04-19 | Asahi Kasei Corp | Fuel cell and vapor permeation membrane used for this |
-
2005
- 2005-01-13 JP JP2005006046A patent/JP2006192364A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS627417A (en) * | 1985-02-09 | 1987-01-14 | Asahi Chem Ind Co Ltd | Semipermeable polymer membrane for drying gas to high degree and gas drying method using the same |
| JPS61187918A (en) * | 1985-02-18 | 1986-08-21 | Asahi Chem Ind Co Ltd | Dry etching method |
| JPH02293551A (en) * | 1989-05-09 | 1990-12-04 | Asahi Glass Co Ltd | Humidifying method |
| JPH07275637A (en) * | 1994-04-08 | 1995-10-24 | Asahi Glass Co Ltd | Dehumidification method |
| JP2001313057A (en) * | 2000-04-27 | 2001-11-09 | Asahi Glass Co Ltd | Manufacturing method of ion-exchange filter for solid polymer fuel cell |
| JP2002117878A (en) * | 2000-10-05 | 2002-04-19 | Asahi Kasei Corp | Fuel cell and vapor permeation membrane used for this |
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