JP2010095419A - Porous electrode substrate, method for manufacturing the same, membrane-electrode assembly, and solid polymer fuel cell - Google Patents
Porous electrode substrate, method for manufacturing the same, membrane-electrode assembly, and solid polymer fuel cell Download PDFInfo
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Abstract
Description
本発明は、液体燃料を用いた固体高分子型燃料電池に用いられる多孔質電極基材およびその製造方法、ならびにその多孔質電極基材を用いた膜−電極接合体および固体高分子型燃料電池に関するものである。 The present invention relates to a porous electrode substrate used for a polymer electrolyte fuel cell using a liquid fuel, a method for producing the same, and a membrane-electrode assembly and a polymer electrolyte fuel cell using the porous electrode substrate. It is about.
本発明は、液体燃料を用いた固体高分子型燃料電池に用いられる多孔質電極基材およびその製造方法、ならびにその多孔質電極基材を用いた膜−電極接合体および固体高分子型燃料電池に関するものである。 The present invention relates to a porous electrode substrate used for a polymer electrolyte fuel cell using a liquid fuel, a method for producing the same, and a membrane-electrode assembly and a polymer electrolyte fuel cell using the porous electrode substrate. It is about.
固体高分子型燃料電池はプロトン伝導性の高分子電解質膜を用いることを特徴としており、水素等の燃料ガスと酸素等の酸化ガスを電気化学的に反応させることにより起電力を得る装置である。固体高分子型燃料電池は、自家発電装置や、自動車等の移動体用の発電装置として利用可能である。
このような固体高分子型燃料電池は、水素イオン（プロトン）を選択的に伝導する高分子電解質膜を有する。また、貴金属系触媒を担持したカーボン粉末を主成分とする触媒層とガス拡散電極基材とを有するガス拡散電極が、触媒層側を内側にして、高分子電解質膜の両面に接合された構造となっている。
A polymer electrolyte fuel cell is characterized by using a proton-conducting polymer electrolyte membrane, and is an apparatus for obtaining an electromotive force by electrochemically reacting a fuel gas such as hydrogen and an oxidizing gas such as oxygen. . The polymer electrolyte fuel cell can be used as a self-power generation device or a power generation device for a moving body such as an automobile.
Such a polymer electrolyte fuel cell has a polymer electrolyte membrane that selectively conducts hydrogen ions (protons). Also, a structure in which a gas diffusion electrode having a catalyst layer mainly composed of carbon powder supporting a noble metal catalyst and a gas diffusion electrode base material is bonded to both surfaces of the polymer electrolyte membrane with the catalyst layer side inside It has become.
このような高分子電解質膜と２枚のガス拡散電極からなる接合体は膜−電極接合体（ＭＥＡ： Ｍｅｍｂｒａｎｅ Ｅｌｅｃｔｒｏｄｅ Ａｓｓｅｍｂｌｙ）と呼ばれている。またＭＥＡの両外側には燃料ガスまたは酸化ガスを供給し、かつ生成ガスおよび過剰ガスを排出することを目的としたガス流路を形成したセパレーターが設置されている。
多孔質電極基材は電気的な接触抵抗を低減し、かつ、セパレーターより供給される燃料ガスまたは酸化ガスがセル外へ漏出することを抑制することを目的として、セパレーターによって数ＭＰａの荷重で締結されるため、機械的強度が必要となる。
Such a joined body composed of a polymer electrolyte membrane and two gas diffusion electrodes is called a membrane-electrode assembly (MEA: Membrane Electrode Assembly). In addition, separators are provided on both outer sides of the MEA so as to supply a fuel gas or an oxidizing gas and to form a gas flow path for the purpose of discharging generated gas and excess gas.
The porous electrode substrate is fastened by a separator with a load of several MPa for the purpose of reducing electrical contact resistance and suppressing leakage of fuel gas or oxidizing gas supplied from the separator to the outside of the cell. Therefore, mechanical strength is required.
さらに、多孔質電極基材は主に次の３つの機能を持つ必要がある。第１に多孔質電極基材の外側に配置されたセパレーターに形成されたガス流路より触媒層中の貴金属系触媒に均一に燃料ガスまたは酸化ガスを供給する機能である。第２に触媒層で反応により生成した水を排出する機能である。第３に触媒層での反応に必要な電子または生成される電子をセパレーターへ導電する機能である。これらの機能を付与するため、多孔質電極基材は一般的に炭素質材料を用いることが有効とされている。
したがって、多孔質電極基材には高い反応ガスおよび酸化ガス透過能と水の排出性、電子導電性が必要である。加えて、一般的な固体高分子型燃料電池で用いられる高分子電解質膜は、含水状態でプロトン伝導性を示すことより、多孔質電極基材には生成水の排水のみでなく、高分子電解質膜の保水という相反する機能が求められている。多孔質電極基材のガス透気度を高くし生成水の排水能を高くしたものでは高分子電解質膜が乾燥することによりプロトン伝導抵抗が増大し、発電性能が低下する。逆に多孔質電極基材のガス透気度を低くし高分子電解質膜の保水能を高めたものでは、生成水の排水不良によって反応ガスおよび酸化ガスの拡散が阻害されるフラッディングにより発電性能が低下する。
Furthermore, the porous electrode substrate mainly needs to have the following three functions. The first function is to supply the fuel gas or the oxidizing gas uniformly to the noble metal catalyst in the catalyst layer from the gas flow path formed in the separator disposed outside the porous electrode substrate. The second function is to discharge water generated by the reaction in the catalyst layer. The third function is to conduct electrons necessary for the reaction in the catalyst layer or generated electrons to the separator. In order to impart these functions, it is generally effective to use a carbonaceous material for the porous electrode substrate.
Therefore, the porous electrode base material needs to have a high reactive gas and oxidizing gas permeability, water discharge property, and electronic conductivity. In addition, the polymer electrolyte membrane used in a general solid polymer fuel cell exhibits proton conductivity in a water-containing state, so that the porous electrode substrate is not only a drainage of generated water, but also a polymer electrolyte. The contradictory function of retaining the membrane is required. When the gas permeability of the porous electrode substrate is increased to increase the drainage capacity of the generated water, the proton conduction resistance increases and the power generation performance decreases due to the drying of the polymer electrolyte membrane. On the contrary, in the case where the gas permeability of the porous electrode substrate is lowered and the water retention capacity of the polymer electrolyte membrane is increased, the power generation performance is improved by flooding in which the diffusion of the reaction gas and the oxidizing gas is hindered due to poor drainage of the generated water. descend.
従来は、機械強度を強くするために、炭素短繊維を抄造後有機高分子で結着させ、高温で焼成し有機高分子を炭素化させたペーパー状の炭素／炭素複合体から成る多孔質電極基材を得ていたが、均一性の高い構造であるために、保水性と、生成水の排水性のバランスを保つことが困難であるという問題があった。また、ガス拡散性、排水性の向上を目的として、貫通孔を形成した多孔質電極基材が提案されているが、貫通孔を形成させるため、機械的強度を維持することが困難であることと、保水性を保つことが困難であるという問題があった。 Conventionally, in order to increase the mechanical strength, a porous electrode made of a paper-like carbon / carbon composite in which short carbon fibers are made with paper and then bound with an organic polymer and then fired at a high temperature to carbonize the organic polymer. Although the base material was obtained, there was a problem that it was difficult to maintain a balance between water retention and drainage of generated water because of the highly uniform structure. In addition, for the purpose of improving gas diffusibility and drainage, a porous electrode base material having through-holes has been proposed, but it is difficult to maintain mechanical strength because the through-holes are formed. There was a problem that it was difficult to maintain water retention.
特許文献１には、厚みが０．０５〜０．５ｍｍで嵩密度が０．３〜０．８ｇ／ｃｍであり、かつ、歪み速度１０ｍｍ／ｍｉｎ、支点間距離２ｃｍおよび試験片幅１ｃｍの条件での３点曲げ試験において曲げ強度が１０ＭＰａ以上でかつ曲げの際のたわみが１．５ｍｍ以上であることを特徴とする燃料電池用多孔質炭素電極基材が記載されている。しかし、この多孔質電極基材は、機械的強度、表面平滑性が高く、十分な導電性は有しているもの、均一性の高い構造であるために、保水性と、生成水の排水性のバランスを保つことが困難であるという問題があった。
特許文献２には、一方の面に触媒層が形成されたカーボンシートからなり、その一方の面から他方の面に亘って複数の貫通孔が形成されていることを特徴とするガス拡散電極が記載されている。この多孔質電極基材は、高いガス拡散性を有しているものの、機械的強度を維持することと、保水性を保つことが困難であるといった問題があった。
In Patent Document 1, the thickness is 0.05 to 0.5 mm, the bulk density is 0.3 to 0.8 g / cm, the strain rate is 10 mm / min, the distance between fulcrums is 2 cm, and the specimen width is 1 cm. Describes a porous carbon electrode substrate for a fuel cell, characterized in that the bending strength is 10 MPa or more and the bending deflection is 1.5 mm or more. However, this porous electrode base material has high mechanical strength, surface smoothness, sufficient conductivity, and a highly uniform structure, so it has water retention and drainage of generated water. There was a problem that it was difficult to maintain the balance.
Patent Document 2 includes a gas diffusion electrode comprising a carbon sheet having a catalyst layer formed on one surface, and a plurality of through holes formed from one surface to the other surface. Are listed. Although this porous electrode base material has high gas diffusivity, there is a problem that it is difficult to maintain mechanical strength and maintain water retention.
本発明は、充分なガス透気度、厚みおよび貫通方向抵抗を備え、燃料電池とした時に、加湿条件の変動によっても電池性能の変動が少ない高い水分管理機能を発揮する多孔質電極基材、その製造方法、膜−電極接合体、および固体高分子型燃料電池を提供することを目的とする。 The present invention provides a porous electrode substrate that has a sufficient moisture permeability, thickness, and resistance in the penetration direction, and exhibits a high moisture management function with little variation in cell performance due to variation in humidification conditions when used as a fuel cell. An object of the present invention is to provide a production method thereof, a membrane-electrode assembly, and a polymer electrolyte fuel cell.
本発明は以下の通りである。
（１）以下の（Ａ）〜（Ｄ）工程を順に行う多孔質電極基材の製造方法。
（Ａ）炭素短繊維とバインダー短繊維とを、分散し炭素短繊維紙を作製する工程；
（Ｂ）炭素化後の残炭率が１５質量％以下の樹脂からなる平均粒径１０ｎｍ〜２μｍの粒子と炭素化後の残炭率が２０質量％以上の樹脂組成物とを炭素短繊維紙に付与する工程；
（Ｃ）加熱加圧して、前記樹脂組成物を硬化する工程；
（Ｄ）樹脂組成物の硬化物を炭素化すると同時に、前記粒子を熱分解する工程
（２）前記炭素化後の残炭率が１５質量％以下の樹脂からなる平均粒径１０ｎｍ〜２μｍの粒子が、アクリル樹脂からなる（１）の多孔質電極基材の製造方法。
（３）前記炭素化後の残炭率が１５質量％以下の樹脂からなる粒子の平均粒径が、３０ｎｍ〜１μｍである（１）又は（２）の多孔質電極基材の製造方法。
（４）以下の工程を順に行う（１）の多孔質電極基材の製造方法。
（Ａ）炭素短繊維とバインダー短繊維とを、分散し炭素短繊維紙を作製する工程；
（Ｂ）平均粒径５０〜６００ｎｍのポリメタクリル酸メチル粒子とフェノール樹脂組成物とを炭素短繊維紙に付与する工程；
（Ｃ）加熱加圧してフェノール樹脂組成物を硬化する工程；および
（Ｄ）フェノール樹脂組成物の硬化物を炭素化すると同時に、ポリメタクリル酸メチル粒子を熱分解する工程
（５）（Ｃ）と（Ｄ）工程の間、酸化処理する工程を行う（１）〜（４）の多孔質電極基材の製造方法。
（６）（１）〜（５）の多孔質電極基材の製造方法で製造される多孔質電極基材。
（７）分散した炭素短繊維同士が、多孔質化した炭素によって接合されている（６）の多孔質電極基材。
（８）（６）又は（７）の多孔質電極基材を用いた膜−電極接合体。
（９）（８）の膜−電極接合体を用いた固体高分子型燃料電池。
The present invention is as follows.
(1) The manufacturing method of the porous electrode base material which performs the following (A)-(D) processes in order.
(A) A step of dispersing carbon short fibers and binder short fibers to produce carbon short fiber paper;
(B) Carbon short fiber paper comprising particles having an average particle size of 10 nm to 2 μm made of a resin having a carbon residue ratio of 15% by mass or less after carbonization and a resin composition having a carbon residue rate of 20% by mass or more after carbonization. Applying to:
(C) a step of curing the resin composition by heating and pressing;
(D) The step of carbonizing the cured product of the resin composition and simultaneously pyrolyzing the particles (2) Particles having an average particle size of 10 nm to 2 μm made of a resin having a carbon residue ratio of 15% by mass or less after the carbonization (1) The manufacturing method of the porous electrode base material which consists of an acrylic resin.
(3) The method for producing a porous electrode substrate according to (1) or (2), wherein an average particle diameter of particles made of a resin having a carbon residue ratio of 15% by mass or less after carbonization is 30 nm to 1 μm.
(4) The manufacturing method of the porous electrode base material of (1) which performs the following processes in order.
(A) A step of dispersing carbon short fibers and binder short fibers to produce carbon short fiber paper;
(B) A step of imparting polymethyl methacrylate particles having an average particle diameter of 50 to 600 nm and a phenol resin composition to carbon short fiber paper;
(C) a step of curing by heating and pressurizing the phenol resin composition; and (D) a step of carbonizing the cured product of the phenol resin composition and simultaneously thermally decomposing the polymethyl methacrylate particles (5) (C); (D) The manufacturing method of the porous electrode base material of (1)-(4) which performs the process oxidized during a process.
(6) A porous electrode substrate produced by the method for producing a porous electrode substrate according to (1) to (5).
(7) The porous electrode base material according to (6), in which dispersed short carbon fibers are joined together by porous carbon.
(8) A membrane-electrode assembly using the porous electrode substrate of (6) or (7).
(9) A polymer electrolyte fuel cell using the membrane-electrode assembly according to (8).
本発明によれば、充分なガス透気度、厚みおよび貫通方向抵抗を備え、燃料電池とした時に、加湿条件の変動によっても電池性能の変動が少ない高い水分管理機能を発揮する多孔質電極基材、その製造方法、膜−電極接合体、および固体高分子型燃料電池を得ることができる。 According to the present invention, a porous electrode substrate having sufficient gas permeability, thickness, and penetration direction resistance, and exhibiting a high moisture management function with little variation in cell performance even when the humidification conditions are varied when a fuel cell is obtained. A material, a manufacturing method thereof, a membrane-electrode assembly, and a polymer electrolyte fuel cell can be obtained.
＜炭素短繊維＞
本発明で用いる炭素短繊維の原料である炭素繊維は、ポリアクリロニトリル系炭素繊維、ピッチ系炭素繊維、レーヨン系炭素繊維などいずれであっても良いが、ポリアクリロニトリル系炭素繊維が好ましい。特に、多孔質炭素電極基材の機械的強度が比較的高くすることができることから、用いる炭素繊維がポリアクリロニトリル（ＰＡＮ）系炭素繊維のみからなることが好ましい。
炭素短繊維の直径は、炭素短繊維の生産コスト、分散性の面から、３〜９μｍであることが好ましい。最終的に得られる多孔質電極基材の平滑性の面から、４μｍ以上、８μｍ以下であることがさらに好ましい。
炭素短繊維の繊維長は、分散性の点から、２〜１２ｍｍが好ましい。
<Short carbon fiber>
The carbon fiber that is a raw material of the short carbon fiber used in the present invention may be any of polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, rayon-based carbon fiber, etc., but polyacrylonitrile-based carbon fiber is preferable. In particular, since the mechanical strength of the porous carbon electrode substrate can be made relatively high, it is preferable that the carbon fiber to be used is made of only polyacrylonitrile (PAN) based carbon fiber.
The diameter of the short carbon fiber is preferably 3 to 9 μm from the viewpoint of production cost and dispersibility of the short carbon fiber. From the aspect of smoothness of the finally obtained porous electrode substrate, it is more preferably 4 μm or more and 8 μm or less.
The fiber length of the short carbon fiber is preferably 2 to 12 mm from the viewpoint of dispersibility.
＜分散＞
本発明において、「分散」とは、炭素短繊維がおおむね一つの面を形成するように横たわっているという意味である。これにより炭素短繊維による短絡や炭素短繊維の折損を防止することができる。炭素短繊維の配向方向は実質的にランダムであっても、特定方向への配向性が高くなっていても良い。
<Dispersion>
In the present invention, “dispersion” means that the carbon short fibers lie so as to form a single plane. Thereby, the short circuit by carbon short fiber and the breakage of carbon short fiber can be prevented. The orientation direction of the short carbon fibers may be substantially random, or the orientation in a specific direction may be high.
＜製造方法＞
本発明の多孔質電極基材の製造方法は、以下に示す方法である。上記の多孔質電極基材は、例えば以下の方法により好適に製造することができる。
以上の（Ａ）〜（Ｄ）工程を順に行い多孔質電極基材を製造する。
（Ａ）炭素短繊維とバインダー短繊維とを、分散し炭素短繊維紙を作製する工程；
（Ｂ）炭素化後の残炭率が１５質量％以下の樹脂からなる平均粒径１０ｎｍ〜２μｍの粒子と炭素化後の残炭率が２０質量％以上の樹脂組成物とを炭素短繊維紙に付与する工程；
（Ｃ）加熱加圧して、前記樹脂組成物を硬化する工程；
（Ｄ）樹脂組成物の硬化物を炭素化すると同時に、前記粒子を熱分解する工程
<Manufacturing method>
The manufacturing method of the porous electrode base material of this invention is the method shown below. Said porous electrode base material can be suitably manufactured, for example with the following method.
The porous electrode base material is manufactured by sequentially performing the above steps (A) to (D).
(A) A step of dispersing carbon short fibers and binder short fibers to produce carbon short fiber paper;
(B) Carbon short fiber paper comprising particles having an average particle size of 10 nm to 2 μm made of a resin having a carbon residue ratio of 15% by mass or less after carbonization and a resin composition having a carbon residue rate of 20% by mass or more after carbonization. Applying to:
(C) a step of curing the resin composition by heating and pressing;
(D) The step of thermally decomposing the particles simultaneously with carbonizing the cured product of the resin composition
＜バインダー短繊維＞
バインダー短繊維は、炭素短繊維を含む炭素短繊維紙中で各成分をつなぎとめるバインダー（糊剤）として使用される。バインダー短繊維としては、ポリビニルアルコール（ＰＶＡ）、ポリ酢酸ビニル、ポリエチレンテレフタレート（ＰＥＴ）などを用いることができる。バインダー短繊維は単体もしくは混合物を用いることができる。特にポリビニルアルコールは炭素短繊維紙作製工程での結着力に優れるため、炭素短繊維の脱落が少なくバインダーとして好ましい。
また、後述する炭素化しない樹脂からなる粒子の分散媒として水を用いる場合には、炭素短繊維紙の強度を維持する観点において、バインダー短繊維として水溶性ではないポリエチレンテレフタレートとポリビニルアルコールの混合物を用いることが好ましい。
<Binder staple fiber>
The binder short fiber is used as a binder (glue) that holds the components together in a carbon short fiber paper containing carbon short fibers. As the binder short fiber, polyvinyl alcohol (PVA), polyvinyl acetate, polyethylene terephthalate (PET), or the like can be used. The binder short fibers can be used alone or as a mixture. In particular, polyvinyl alcohol is preferable as a binder because it has excellent binding power in the short carbon fiber paper making process, and the short carbon fibers do not fall off.
In addition, when water is used as a dispersion medium of particles made of a non-carbonized resin, which will be described later, from the viewpoint of maintaining the strength of carbon short fiber paper, a mixture of polyethylene terephthalate and polyvinyl alcohol that is not water-soluble as a binder short fiber is used. It is preferable to use it.
＜炭素短繊維紙を作製する工程＞
炭素短繊維とバインダー短繊維とを分散させて、炭素短繊維紙を作製する方法としては、液体の媒体中に炭素短繊維とバインダー短繊維を分散させて抄造する湿式法や、空気中に炭素短繊維とバインダー短繊維を分散させて降り積もらせる乾式法が適用できるが、中でも湿式法が好ましい。炭素短繊維が単繊維に分散するのを助け、分散した単繊維が再び収束を防止するのを防ぐことができる。
炭素短繊維とバインダー短繊維を混合する方法としては、炭素短繊維とともに水中で攪拌分散させる方法と、直接混ぜ込む方法があるが、均一に分散させるためには水中で拡散分散させる方法が好ましい。このようにバインダー短繊維を混ぜることにより、炭素繊維紙の強度を保持し、その製造途中で炭素繊維紙から炭素短繊維が剥離したり、炭素短繊維の配向が変化したりするのを防止することができる。
また、炭素短繊維紙の作製は連続で行なう方法やバッチ式で行なう方法があるが、本発明において行なう炭素短繊維紙の作製は、特に目付のコントロールが容易であるという点と生産性及び機械的強度の観点から連続が好ましい。炭素短繊維紙の目付けは、１０〜２００ｇ／ｍ２とすることが好ましい。
<Process for producing short carbon fiber paper>
Carbon short fiber and binder short fiber are dispersed to produce carbon short fiber paper. A wet method in which carbon short fiber and binder short fiber are dispersed in a liquid medium to make paper, or carbon in the air is used. A dry method in which short fibers and binder short fibers are dispersed and piled up can be applied. Among these, a wet method is preferable. The short carbon fibers can be dispersed into the single fibers, and the dispersed single fibers can be prevented from preventing convergence again.
As a method of mixing the short carbon fiber and the short binder fiber, there are a method of stirring and dispersing in water together with the carbon short fiber and a method of mixing directly, but a method of diffusing and dispersing in water is preferable for uniform dispersion. By mixing the binder short fibers in this way, the strength of the carbon fiber paper is maintained, and it is possible to prevent the carbon short fibers from being peeled off from the carbon fiber paper during the production and the orientation of the carbon short fibers from being changed. be able to.
In addition, short carbon fiber paper can be produced continuously or batchwise. The production of carbon short fiber paper in the present invention is particularly easy to control the basis weight, productivity and machine. From the viewpoint of mechanical strength, continuous is preferable. The basis weight of the short carbon fiber paper is preferably 10 to 200 g / m 2 .
＜炭素化後の残炭率が２０質量％以上の樹脂組成物＞
本発明で炭素化後の残炭率が２０質量％以上の樹脂組成物として用いる樹脂組成物は、炭素化後も導電性物質として残存する物質であり、常温において粘着性、あるいは流動性を示すものが好ましい。フェノール樹脂、フラン樹脂、エポキシ樹脂、メラミン樹脂、イミド樹脂、ウレタン樹脂、アラミド樹脂、ピッチ等を単体若しくは混合物として用いることができ、用いる樹脂の種類、後述する樹脂の含浸の際の含浸量、硬化、炭素化温度によって残存する炭素化量が異なる。ここで残炭率とは、樹脂組成物を１２００℃以上の温度で炭素化した時の質量を炭素化前の樹脂組成物の質量で割って１００を乗じた値である。
フェノール樹脂組成物として、フェノール類とアルデヒド類の反応によって得られるレゾールタイプフェノール樹脂組成物単体を用いることもできるが、固体の熱融着性を示すノボラックタイプのフェノール樹脂組成物を混合させることもが好ましい。
<Resin composition having a residual carbon ratio of 20% by mass or more after carbonization>
The resin composition used as a resin composition having a carbon residue ratio of 20% by mass or more after carbonization in the present invention is a substance that remains as a conductive substance even after carbonization and exhibits adhesiveness or fluidity at room temperature. Those are preferred. Phenolic resin, furan resin, epoxy resin, melamine resin, imide resin, urethane resin, aramid resin, pitch, etc. can be used as a single substance or as a mixture, the type of resin used, the amount of impregnation during resin impregnation described below, and curing The amount of remaining carbonization varies depending on the carbonization temperature. Here, the residual carbon ratio is a value obtained by dividing the mass when the resin composition is carbonized at a temperature of 1200 ° C. or higher by the mass of the resin composition before carbonization and multiplying by 100.
As the phenol resin composition, a resol type phenol resin composition obtained by reaction of phenols and aldehydes can be used alone, or a novolak type phenol resin composition exhibiting solid heat-fusibility can be mixed. Is preferred.
＜炭素化後の残炭率が１５質量％以下の樹脂からなる粒子＞
本発明で炭素化後の残炭率が１５質量％以下の樹脂からなる粒子に用いる樹脂は、炭素化時に熱分解して、導電性物質としてほとんど残存しない物質が好ましい。炭素化後の残炭率が１０質量％以下の樹脂がより好ましい。ここで残炭率とは、樹脂を１２００℃以上の温度で炭素化した時の質量を炭素化前の樹脂の質量で割って１００を乗じた値である。
残炭率が１５質量％以下の樹脂としては、ポリメタクリル酸メチル等のアクリル樹脂、ポリスチレン、テトラフルオロエチレン等のフッ素樹脂、ポリエチレン、ポリ酢酸ビニル、ポリビニルアルコール等を単体若しくは混合物として用いることができ、炭素化可能な樹脂として、フェノール樹脂を用いる場合は、ポリメタクリル酸メチル等のアクリル樹脂やポリスチレン等が炭素化後の残炭率が２０質量％以上の樹脂組成物の溶液中で不溶であるため、粒子形状を維持できるという点で好ましい。
<Particles made of resin having a carbon residue ratio of 15% by mass or less after carbonization>
In the present invention, the resin used for the particles composed of a resin having a carbon residue ratio of 15% by mass or less after carbonization is preferably a substance that is thermally decomposed during carbonization and hardly remains as a conductive substance. A resin having a carbon residue ratio after carbonization of 10% by mass or less is more preferable. Here, the residual carbon ratio is a value obtained by dividing the mass when the resin is carbonized at a temperature of 1200 ° C. or higher by the mass of the resin before carbonization and multiplying by 100.
As the resin having a residual carbon ratio of 15% by mass or less, an acrylic resin such as polymethyl methacrylate, a fluororesin such as polystyrene or tetrafluoroethylene, polyethylene, polyvinyl acetate, polyvinyl alcohol, or the like can be used alone or as a mixture. When a phenol resin is used as the carbonizable resin, an acrylic resin such as polymethyl methacrylate or polystyrene is insoluble in a solution of a resin composition having a residual carbon ratio of 20% by mass or more after carbonization. Therefore, it is preferable in that the particle shape can be maintained.
炭素化後の残炭率が１５質量％以下の樹脂からなる粒子の形状は、真球状、楕円状、ブロック状等どのような形態であって良いが、炭素化時に消失することによって形成される空孔が連続的である点において真球状が好ましい粒子の平均粒子径は、炭素短繊維とバインダー短繊維から成る炭素短繊維紙中の空隙に包含させる点において、２μｍ以下であることが好ましい。また形成させる空隙によって保水性、排水性が向上する点において１０ｎｍ以上であることが好ましい。さらに好ましくは、３０ｎｍ以上、１μｍ以下である。
特に好ましくは、５０〜６００ｎｍである。粒子径の分布の分散性は高くても低くても良いが、より精密に空隙サイズを制御できるという点から単分散性が高いほうが好ましい。
また、単分散性が高い粒子径を持つ炭素化後の残炭率が１５質量％以下の樹脂からなる粒子単体を用いても良いが、単分散性が高い粒子径を持つ炭素化後の残炭率が１５質量％以下の樹脂からなる粒子が複数からなる混合物を用いても良い。炭素化後の残炭率が１５質量％以下の樹脂からなる粒子の製造方法は、例えば、シード乳化重合法が挙げられる。
分散媒は、粒子が溶解せず、取り扱い良好な水系溶媒が好ましい。
The shape of the particles made of a resin having a carbon residue ratio of 15% by mass or less after carbonization may be any shape such as a spherical shape, an elliptical shape, or a block shape, but is formed by disappearing during carbonization. The average particle diameter of particles that are preferably spherical in terms of continuous pores is preferably 2 μm or less in terms of inclusion in voids in short carbon fiber paper composed of short carbon fibers and short binder fibers. Moreover, it is preferable that it is 10 nm or more at the point which water retention and drainage property improve with the space | gap formed. More preferably, it is 30 nm or more and 1 μm or less.
Most preferably, it is 50-600 nm. The dispersibility of the particle size distribution may be high or low, but higher monodispersity is preferable from the viewpoint that the pore size can be controlled more precisely.
Alternatively, a single particle made of a resin having a particle size with a high monodispersity and a carbonization rate of 15% by mass or less after carbonization may be used. You may use the mixture which consists of several particle | grains which consist of resin with a charcoal rate of 15 mass% or less. Examples of a method for producing particles made of a resin having a carbon residue ratio of 15% by mass or less after carbonization include a seed emulsion polymerization method.
The dispersion medium is preferably an aqueous solvent that does not dissolve particles and is well handled.
＜炭素化後の残炭率が１５質量％以下の樹脂からなる粒子と炭素化後の残炭率が２０質量％以上の樹脂組成物とを炭素短繊維紙に付与する方法＞
炭素短繊維紙に樹脂を付与することができればよく、特に限定されないが、コーターを用いて炭素短繊維紙表面に樹脂を均一にコートする方法、絞り装置を用いるｄｉｐ−ｎｉｐ方法、若しくは炭素短繊維紙と樹脂フィルムを重ねて、樹脂を炭素短繊維紙に転写する方法が、連続的に行なうことができ、生産性及び長尺ものも製造できるという点で好ましい。混合分散媒は、炭素化後の残炭率が１５質量％以下の樹脂からなる粒子は溶解せず、炭素化後の残炭率が２０質量％以上の樹脂組成物は溶解するものが好ましい。
<Method of Giving Carbon Short Fiber Paper Particles Made of Resin with Carbonized Residual Carbon Ratio of 15% by Mass or Less and Resin Composition with Carbonated Carbonate Ratio of 20% by Mass or Higher after Carbonization>
There is no particular limitation as long as the resin can be applied to the carbon short fiber paper, but there is no particular limitation. A method of uniformly coating the resin on the surface of the carbon short fiber paper using a coater, a dip-nip method using a drawing device, or a carbon short fiber A method of superposing paper and a resin film and transferring the resin to a short carbon fiber paper can be carried out continuously, and is preferable in terms of productivity and production of a long product. It is preferable that the mixed dispersion medium does not dissolve particles composed of a resin having a carbon residue ratio of 15% by mass or less after carbonization but dissolves a resin composition having a carbon residue ratio of 20% by mass or more after carbonization.
多孔質電極基材に排水性と保湿性、ガス拡散性のバランスを保つことができる水分管理機能を発現させるためには炭素化後の残炭率が２０質量％以上の樹脂組成物が炭化した多孔質炭素が、炭素短繊維１００質量部に対し２０〜５０質量部であることが好ましいため、炭素短繊維紙に付与する炭素化後の残炭率が２０質量％以上の樹脂組成物量は、炭素短繊維１００質量部に対し、７０〜１２０質量部付与することが好ましい。
炭素化後の残炭率が２０質量％以上の樹脂組成物が炭化した多孔質炭素の強度を維持し、かつ炭素化後の残炭率が２０質量％以上の樹脂組成物に炭素化時に形成される空隙が独立孔にならず、連続的孔が形成されるためには炭素短繊維紙中の炭素化後の残炭率が１５質量％以下の樹脂からなる粒子の量は、炭素化後の残炭率が２０質量％以上の樹脂組成物１００質量部に対し、１００〜５００質量部包含させることが好ましく、炭素化後の残炭率が１５質量％以下の樹脂からなる粒子の、熱分解によって形成される空隙をより有効に形成させるためには、２５０〜４００質量部包含させることがより好ましい。
In order to develop a moisture management function capable of maintaining a balance between drainage, moisture retention, and gas diffusibility in the porous electrode substrate, a resin composition having a carbon residue ratio of 20% by mass or more after carbonization was carbonized. Since it is preferable that the porous carbon is 20 to 50 parts by mass with respect to 100 parts by mass of the carbon short fibers, the amount of the resin composition after carbonization to give to the carbon short fiber paper is 20% by mass or more. It is preferable to apply 70 to 120 parts by mass with respect to 100 parts by mass of the short carbon fibers.
The resin composition having a carbon residue ratio of 20% by mass or more after carbonization maintains the strength of the carbonized carbon, and the carbon composition after carbonization is formed at the time of carbonization to a resin composition having a carbon residue ratio of 20% by mass or more. In order for the voids to be formed to be independent pores and for continuous pores to be formed, the amount of particles made of a resin having a carbon residue ratio of 15% by mass or less after carbonization in the short carbon fiber paper is It is preferable to include 100 to 500 parts by mass with respect to 100 parts by mass of the resin composition having a residual carbon ratio of 20% by mass or more, and heat of particles made of a resin having a residual carbon ratio after carbonization of 15% by mass or less. In order to more effectively form voids formed by decomposition, it is more preferable to include 250 to 400 parts by mass.
＜加熱加圧＞
炭素化後の残炭率が２０質量％以上の樹脂組成物を含浸された前駆体シートは、炭素化処理の前に、２００℃以下の温度で加熱加圧して硬化することが、炭素短繊維を炭素化後の残炭率が２０質量％以上の樹脂組成物で融着させ、かつ、多孔質電極基材の厚みムラを低減できるという点で好ましい。加熱加圧は、前駆体シートを均等に加熱加圧できる技術であれば、いかなる技術も適用できる。その例としては、上下両面から平滑な剛板にて熱プレスする方法や連続ベルトプレス装置を用いて行う方法がある。
<Heating and pressing>
The precursor sheet impregnated with a resin composition having a carbon residue ratio of 20% by mass or more after carbonization is cured by heating and pressurizing at a temperature of 200 ° C. or less before carbonization treatment. Is preferably fused with a resin composition having a residual carbon ratio of 20% by mass or more after carbonization, and thickness unevenness of the porous electrode substrate can be reduced. Any technique can be applied to the heat and pressure as long as the technique can uniformly heat and press the precursor sheet. As an example, there are a method of performing hot pressing with smooth rigid plates from both upper and lower surfaces, and a method of performing using a continuous belt press apparatus.
連続製造による前駆体シートを加熱加圧する場合は、連続ベルトプレス装置を用いて行う方法が、長尺の多孔質電極基材ができるという点で好ましい。多孔質電極基材が長尺であれば、多孔質電極基材の生産性が高くなるだけでなく、その後のＭＥＡ製造も連続で行うことができ、燃料電池のコスト低減化に大きく寄与することができる。また、本発明の多孔質電極基材は、連続的に巻き取ることも可能で、多孔質電極基材や燃料電池の生産性、コストの観点から好ましい。連続ベルト装置におけるプレス方法としては、ロールプレスによりベルトに線圧で圧力を加える方法と液圧ヘッドプレスにより面圧でプレスする方法があるが、後者の方がより平滑な多孔質電極基材が得られるという点で好ましい。
加熱温度は、効果的に表面を平滑にするために、２００℃未満が好ましく、１２０〜１９０℃がより好ましい。
In the case where the precursor sheet by continuous production is heated and pressurized, a method using a continuous belt press apparatus is preferable in that a long porous electrode substrate can be formed. If the porous electrode substrate is long, not only the productivity of the porous electrode substrate is increased, but also the subsequent MEA production can be performed continuously, which greatly contributes to the cost reduction of the fuel cell. Can do. Moreover, the porous electrode base material of the present invention can be continuously wound, and is preferable from the viewpoint of productivity and cost of the porous electrode base material and the fuel cell. As a pressing method in the continuous belt device, there are a method of applying pressure to the belt by a roll press by a linear pressure and a method of pressing by a surface pressure by a hydraulic head press, but the latter is a smoother porous electrode substrate. It is preferable in that it is obtained.
In order to effectively smooth the surface, the heating temperature is preferably less than 200 ° C, more preferably 120 to 190 ° C.
圧力は特に限定されないが、炭素化後の残炭率が２０質量％以上の樹脂組成物の比率が多い場合は、圧力が低くても前駆体シートの表面を平滑にすることが容易である。このとき必要以上にプレス圧を高くすることは、加圧時に炭素短繊維を破壊する、多孔質電極基材としたときその組織が緻密になりすぎるなどの問題が生じる場合がある。例えば、２０ｋＰａ〜１０ＭＰａの圧力で加圧することができる。
加熱加圧の時間は、例えば３０秒〜１０分とすることができる。
剛板に挟んで、又連続ベルト装置で前駆体シートの加熱加圧を行う時は、剛板やベルトに炭素化後の残炭率が２０質量％以上の樹脂組成物などが付着しないようにあらかじめ剥離剤を塗っておくか、前駆体シートと剛板やベルトとの間に離型紙を挟んで行うことが好ましい。
The pressure is not particularly limited, but if the ratio of the resin composition having a carbon residue ratio of 20% by mass or more after carbonization is large, it is easy to smooth the surface of the precursor sheet even if the pressure is low. If the press pressure is increased more than necessary at this time, there may be problems such as breaking the short carbon fibers during the pressurization or becoming too dense when the porous electrode base material is used. For example, pressurization can be performed at a pressure of 20 kPa to 10 MPa.
The time for heating and pressing can be, for example, 30 seconds to 10 minutes.
When the precursor sheet is heated and pressurized with a rigid plate or with a continuous belt device, a resin composition having a carbon residue ratio of 20% by mass or more after carbonization does not adhere to the rigid plate or belt. It is preferable to apply a release agent in advance or sandwich a release paper between the precursor sheet and the rigid plate or belt.
＜炭素化＞
前駆体シートを加熱加圧後に炭素化する、さらにその加熱加圧後の前駆体シートを酸化処理した後に炭素化することが可能である。前駆体シートの炭素化は、炭素短繊維を炭素化後の残炭率が２０質量％以上の樹脂組成物で融着させ、かつ炭素化後の残炭率が２０質量％以上の樹脂組成物を炭素化することより、多孔質電極基材の機械的強度と導電性を発現させることを目的に行う。
炭素化は、多孔質電極基材の導電性を高めるために、不活性ガス中で行うことが好ましい。炭素化は、１０００℃以上の温度で行う。１０００〜３０００℃の温度範囲で炭素化することが好ましく１０００〜２２００℃の温度範囲がより好ましい。１０００℃未満の温度で炭素化して得られた多孔質電極基材は、導電性が十分ではない。炭素化の前に３００〜８００℃の程度の不活性雰囲気での焼成による前処理を行っても良い。
炭素化の時間は、例えば１０分〜１時間とすることができる。
<Carbonization>
The precursor sheet can be carbonized after being heated and pressed, and further, the precursor sheet after the heating and pressing can be oxidized and then carbonized. Carbonization of the precursor sheet is a resin composition in which short carbon fibers are fused with a resin composition having a residual carbon ratio of 20% by mass or more after carbonization, and the residual carbon ratio after carbonization is 20% by mass or more. This is performed for the purpose of expressing the mechanical strength and conductivity of the porous electrode base material by carbonizing.
Carbonization is preferably performed in an inert gas in order to increase the conductivity of the porous electrode substrate. Carbonization is performed at a temperature of 1000 ° C. or higher. Carbonization is preferably performed in a temperature range of 1000 to 3000 ° C, and a temperature range of 1000 to 2200 ° C is more preferable. The porous electrode substrate obtained by carbonization at a temperature of less than 1000 ° C. does not have sufficient conductivity. Prior to carbonization, pretreatment by firing in an inert atmosphere of about 300 to 800 ° C. may be performed.
The time for carbonization can be, for example, 10 minutes to 1 hour.
連続製造による前駆体シートを炭素化する場合は、前駆体シートの全長にわたって連続で炭素化を行うことが、低コスト化という観点で好ましい。多孔質電極基材が長尺であれば、多孔質電極基材の生産性が高くなるだけでなく、その後のＭＥＡ製造も連続で行うことができ、燃料電池のコスト低減に大きく寄与することができる。また、本発明の多孔質電極基材は、連続的に巻き取ることも可能で、多孔質電極基材や燃料電池の生産性、コストの観点から好ましい。 When carbonizing the precursor sheet by continuous manufacture, it is preferable from a viewpoint of cost reduction to perform carbonization continuously over the full length of a precursor sheet. If the porous electrode substrate is long, not only the productivity of the porous electrode substrate is increased, but also the subsequent MEA production can be performed continuously, which can greatly contribute to the cost reduction of the fuel cell. it can. In addition, the porous electrode substrate of the present invention can be continuously wound, and is preferable from the viewpoints of productivity and cost of the porous electrode substrate and the fuel cell.
＜酸化処理＞
炭素化後の残炭率が２０質量％以上の樹脂組成物を含浸された前駆体シートは、加熱加圧した後、２００℃以上３００℃未満の温度で酸化処理することが、炭素短繊維を炭素化後の残炭率が２０質量％以上の樹脂組成物でより融着させ、かつ、炭素化後の残炭率が２０質量％以上の樹脂組成物の炭素化率を向上させるという点で好ましい。
酸化処理は、２００〜３００℃の温度範囲で行うことが好ましく、２４０〜２７０℃で行うことがより好ましい。酸化処理は、大気雰囲気下で行うことが好ましい。
酸化処理の時間は、例えば３０分〜２時間とすることができる。
連続製造による前駆体シートを酸化処理する場合は、前駆体シートの全長にわたって連続に行うことが低コスト化という観点で好ましい。多孔質電極基材が長尺であれば、多孔質電極基材の生産性が高くなるだけでなく、その後のＭＥＡ製造も連続で行うことができ、燃料電池のコスト低減に大きく寄与することができる。また本発明の多孔質電極基材は、連続的に巻き取ることも可能で、多孔質電極基材や燃料電池の生産性、コストの観点から好ましい。
<Oxidation treatment>
The precursor sheet impregnated with a resin composition having a carbon residue ratio of 20% by mass or more after carbonization is heated and pressurized, and then oxidized at a temperature of 200 ° C. or more and less than 300 ° C. In terms of improving the carbonization rate of a resin composition having a residual carbon ratio after carbonization of 20% by mass or more and further fusing with a resin composition having a residual carbon ratio of 20% by mass or more after carbonization. preferable.
The oxidation treatment is preferably performed at a temperature range of 200 to 300 ° C, more preferably at 240 to 270 ° C. The oxidation treatment is preferably performed in an air atmosphere.
The oxidation treatment time can be, for example, 30 minutes to 2 hours.
When oxidizing the precursor sheet by continuous manufacture, it is preferable to carry out continuously over the full length of a precursor sheet from a viewpoint of cost reduction. If the porous electrode substrate is long, not only the productivity of the porous electrode substrate is increased, but also the subsequent MEA production can be performed continuously, which can greatly contribute to the cost reduction of the fuel cell. it can. Further, the porous electrode substrate of the present invention can be continuously wound, and is preferable from the viewpoints of productivity and cost of the porous electrode substrate and the fuel cell.
＜多孔質電極基材＞
本発明の多孔質電極基材の厚みは、５０〜３００μｍであることが好ましい。
<Porous electrode substrate>
The thickness of the porous electrode substrate of the present invention is preferably 50 to 300 μm.
＜膜−電極接合体（ＭＥＡ）、固体高分子型燃料電池＞
以上のような本発明の多孔質電極基材は、膜−電極接合体に好適に用いることができる。そして、本発明の多孔質電極基材を用いた膜−電極接合体は、固体高分子型燃料電池に好適に用いることができる。
<Membrane-electrode assembly (MEA), polymer electrolyte fuel cell>
The porous electrode substrate of the present invention as described above can be suitably used for a membrane-electrode assembly. The membrane-electrode assembly using the porous electrode substrate of the present invention can be suitably used for a polymer electrolyte fuel cell.
以下、本発明を実施例により、さらに具体的に説明する。実施例中の各物性値等は以下の方法で測定した。 Hereinafter, the present invention will be described more specifically with reference to examples. Each physical property value in the examples was measured by the following method.
（１）ガス透気度
ＪＩＳ規格Ｐ−８１１７に準拠し、ガーレーデンソメーターを使用して２００ｍＬの空気が透過するのにかかった時間を測定し、ガス透気度を算出した。
(1) Gas air permeability Based on JIS standard P-8117, the time required for 200 mL of air to permeate was measured using a Gurley densometer, and the gas air permeability was calculated.
（２）厚み
多孔質電極基材の厚みは、厚み測定装置ダイヤルシックネスゲージ７３２１（商品名、ミツトヨ製）を使用して測定した。測定子の大きさは直径１０ｍｍで、測定圧力は１．５ｋＰａとした。
(2) Thickness The thickness of the porous electrode substrate was measured using a thickness measuring device dial thickness gauge 7321 (trade name, manufactured by Mitutoyo Corporation). The size of the probe was 10 mm in diameter, and the measurement pressure was 1.5 kPa.
（３）貫通方向抵抗
多孔質電極基材の厚さ方向の電気抵抗（貫通方向抵抗）は、試料を金メッキした銅板に挟み、金メッキした銅板の上下から１ＭＰａで加圧し、１０ｍＡ／ｃｍ２の電流密度で電流を流したときの抵抗値を測定し、次式より求めた。
(3) Penetration direction resistance The thickness direction electrical resistance (penetration direction resistance) of the porous electrode substrate is obtained by sandwiching a sample between gold-plated copper plates and pressurizing at 1 MPa from above and below the gold-plated copper plate, and a current of 10 mA / cm 2 . The resistance value when a current was passed at a density was measured and obtained from the following equation.
貫通抵抗（ｍΩ・ｃｍ２）＝測定抵抗値（Ω）×試料面積（ｃｍ２） Penetration resistance (mΩ · cm 2 ) = Measured resistance value (Ω) × Sample area (cm 2 )
（４）平均粒子径
炭素化後の残炭率が１５質量％以下の樹脂からなる粒子の平均粒子径の算出は、電子顕微鏡等を用いて複数個の粒子の粒子径を計測する方法、炭素化後の残炭率が１５質量％以下の樹脂からなる粒子の溶液を用いて、光散乱法によって算出する方法等が挙げられるが、真球度が高い炭素化後の残炭率が１５質量％以下の樹脂からなる粒子を用いる場合は、走査型電子顕微鏡を用いて、５０個以上の炭素化後の残炭率が１５質量％以下の樹脂からなる粒子の直径を計測することによって算出した。
(4) Average particle diameter The calculation of the average particle diameter of particles made of a resin having a carbon residue ratio of 15% by mass or less after carbonization is a method of measuring the particle diameter of a plurality of particles using an electron microscope or the like, carbon Examples include a method of calculating by a light scattering method using a solution of particles made of a resin having a residual carbon ratio of 15% by mass or less after conversion, and the residual carbon ratio after carbonization having a high sphericity is 15%. %, When using particles made of resin of not more than 50%, it was calculated by measuring the diameter of particles made of resin having a residual carbon ratio of not less than 50% by mass using a scanning electron microscope. .
（ポリメタクリル酸メチル粒子の分散液の製造）
温度計、窒素導入管、攪拌装置を備えたフラスコに、純水１００質量部、ジアルキルスルホコハク酸ナトリウム塩（商品名；ペレックスＯ−ＴＰ、花王（株）製）０．１０質量部とを入れ、窒素雰囲気下で攪拌し、内温を８０℃に昇温させた。次いで、シードとなるモノマーのメチルメタクリレート（ＭＭＡ）を５０質量部加えた後、開始剤の過硫酸カリウムを０．０５質量部加え１時間反応させた。その後、純水５０質量部、メチルメタクリレート９０質量部、ジアルキルスルホコハク酸ナトリウム塩１．００質量部の混合分散液を５時間かけて滴下した。さらに、１時間内温を保持し、粒子水分散液を得た。得られた粒子水分散液を粒子固形分が２０質量％になるよう純粋で希釈した。
初期に仕込むジアルキルスルホコハク酸ナトリウム塩を０．１０質量部から以下の量に変えて平均粒子径の異なる粒子を製造した。
(Production of polymethyl methacrylate particle dispersion)
In a flask equipped with a thermometer, a nitrogen introduction tube, and a stirrer, 100 parts by mass of pure water and 0.10 parts by mass of dialkylsulfosuccinic acid sodium salt (trade name; Perex O-TP, manufactured by Kao Corp.) The mixture was stirred under a nitrogen atmosphere, and the internal temperature was raised to 80 ° C. Subsequently, after adding 50 parts by mass of methyl methacrylate (MMA) as a seed monomer, 0.05 part by mass of potassium persulfate as an initiator was added and reacted for 1 hour. Thereafter, a mixed dispersion of 50 parts by mass of pure water, 90 parts by mass of methyl methacrylate and 1.00 parts by mass of sodium dialkylsulfosuccinate was dropped over 5 hours. Further, the internal temperature was maintained for 1 hour to obtain an aqueous particle dispersion. The obtained aqueous particle dispersion was diluted pure with a solid content of 20% by mass.
The dialkylsulfosuccinic acid sodium salt initially charged was changed from 0.10 parts by mass to the following amount to produce particles having different average particle diameters.
（実施例１）
炭素短繊維として、平均繊維径が７μｍ、平均繊維長が３ｍｍのポリアクリロニトリ（ＰＡＮ）系炭素繊維を用意した。また、バインダー短繊維として、平均繊維長が３ｍｍのポリビニルアルコール（ＰＶＡ）短繊維（商品名：ＶＢＰ１０５−１、クラレ株式会社製）、とポリエチレンテレフタレート（ＰＥＴ）短繊維を用意した。
炭素短繊維１００質量部を水中に均一に分散して単繊維に解繊し、十分に分散したところに、ＰＶＡ短繊維４０質量部、ＰＥＴ短繊維３０質量部を均一に分散し、標準角型シートマシン（熊谷理機工業（株）製、商品名：Ｎｏ．２５５５ 標準角型シートマシン）を用いてＪＩＳ Ｐ−８２０９法に準拠して手動により炭素短繊維紙の作製を行い、乾燥させて、目付けが３４ｇ／ｍ２の炭素短繊維紙を得た。炭素短繊維の分散状態は良好であった。
炭素化後の残炭率が１５質量％以下の樹脂からなる粒子として真球状のポリメタクリル酸メチル（ＰＭＭＡ）粒子（平均粒子径２３３ｎｍ）水分散液を用意した。
得られた炭素短繊維紙を平均粒子径２３３ｎｍの単分散性の高いポリメタクリル酸メチル粒子を２０質量％含む水分散液を含浸し、室温にて８時間乾燥させることによって、目付けが９４ｇ／ｍ２のポリメタクリル酸メチル粒子が付与された前駆体シートを得た。続いて、ポリメタクリル酸メチル粒子が付与された前駆体シートに、フェノール樹脂組成物（大日本インキ化学株式会社製フェノライトＪ−３２５）を１３質量％含むフェノール樹脂組成物のメタノール溶液を含浸させ、室温で８時間乾燥させることによって、目付けが１１１ｇ／ｍ２のフェノール樹脂組成物とポリメタクリル酸メチル粒子が付与された前駆体シートを得た。これは、炭素短繊維１００質量部に対し、フェノール樹脂組成物を８６質量部付着させたことになる。また、フェノール樹脂組成物１００質量部に対し、ポリメタクリル酸メチル粒子を３３８質量部混合させたことになる。
Example 1
As short carbon fibers, polyacrylonitrile (PAN) carbon fibers having an average fiber diameter of 7 μm and an average fiber length of 3 mm were prepared. As binder short fibers, polyvinyl alcohol (PVA) short fibers (trade name: VBP105-1, manufactured by Kuraray Co., Ltd.) and polyethylene terephthalate (PET) short fibers having an average fiber length of 3 mm were prepared.
100 parts by mass of carbon short fibers are uniformly dispersed in water, defibrated into single fibers, and when sufficiently dispersed, 40 parts by mass of PVA short fibers and 30 parts by mass of PET short fibers are uniformly dispersed to form a standard square shape Using a sheet machine (Kumagaya Riki Kogyo Co., Ltd., trade name: No. 2555 standard square sheet machine), carbon short fiber paper is manually manufactured according to JIS P-8209 method and dried. A carbon short fiber paper having a basis weight of 34 g / m 2 was obtained. The dispersion state of the short carbon fibers was good.
Spherical polymethyl methacrylate (PMMA) particles (average particle diameter of 233 nm) in water dispersion was prepared as particles made of a resin having a carbon residue ratio of 15% by mass or less after carbonization.
The obtained carbon short fiber paper was impregnated with an aqueous dispersion containing 20% by mass of highly monodisperse polymethyl methacrylate particles having an average particle diameter of 233 nm and dried at room temperature for 8 hours, whereby the basis weight was 94 g / m. The precursor sheet | seat provided with the polymethyl methacrylate particle | grains of 2 was obtained. Subsequently, a precursor sheet provided with polymethyl methacrylate particles is impregnated with a methanol solution of a phenol resin composition containing 13% by mass of a phenol resin composition (Phenolite J-325 manufactured by Dainippon Ink & Chemicals, Inc.). By drying at room temperature for 8 hours, a precursor sheet provided with a phenol resin composition having a basis weight of 111 g / m 2 and polymethyl methacrylate particles was obtained. This means that 86 parts by mass of the phenol resin composition is attached to 100 parts by mass of the short carbon fibers. Moreover, 338 mass parts of polymethyl methacrylate particles were mixed with 100 mass parts of the phenol resin composition.
次に、２枚重ね合わせたこの前駆体シートを２枚のシリコーン系離型剤をコートした紙に挟んだ後、バッチプレス装置で１８０℃、３０ｋＰａの条件下で３分間加熱加圧した。
加熱加圧した前駆体シートをバッチ炭素化炉にて、窒素ガス雰囲気中、２０００℃の条件下で１時間炭素化することで多孔質電極基材を得た。得られた多孔質電極基材は、ガス透気度、厚み、貫通方向抵抗がそれぞれ良好な結果であった。結果を表１に示した。
なお、得られた多孔質電極基材の走査型電子顕微鏡による表面観察写真を図１に示す。分散した炭素短繊維同士が、炭多孔質化した炭素によって接合されており、空隙サイズが用いたポリメタクリル酸メチル粒子の平均粒子径に依存して約２５０〜３００ｎｍであることが確認できた。
Next, two precursor sheets that were overlapped were sandwiched between two sheets of paper coated with a silicone release agent, and then heated and pressurized for 3 minutes at 180 ° C. and 30 kPa using a batch press apparatus.
A porous electrode substrate was obtained by carbonizing the heated and pressurized precursor sheet in a batch carbonization furnace in a nitrogen gas atmosphere at 2000 ° C. for 1 hour. The obtained porous electrode base material had good gas permeability, thickness, and penetration direction resistance. The results are shown in Table 1.
In addition, the surface observation photograph by the scanning electron microscope of the obtained porous electrode base material is shown in FIG. It was confirmed that the dispersed short carbon fibers were joined by carbon made into carbon porous, and the pore size was about 250 to 300 nm depending on the average particle diameter of the polymethyl methacrylate particles used.
（実施例２）
ポリメタクリル酸メチル粒子の平均粒子径を５５０ｎｍとしたこと以外は実施例１と同様にして多孔質電極基材を得た。得られた多孔質電極基材は、走査型電子顕微鏡による表面観察により分散した炭素短繊維同士が、炭多孔質化した炭素によって接合されており、炭化樹脂中の空隙サイズが用いたポリメタクリル酸メチル粒子の平均粒子径に依存して約６００〜７００ｎｍであり、実施例１と比較して大きくなっていることが確認できた。また、ガス透気度、厚み、貫通方向抵抗もそれぞれ良好な結果であった。評価結果を表１に示した。
(Example 2)
A porous electrode substrate was obtained in the same manner as in Example 1 except that the average particle diameter of the polymethyl methacrylate particles was 550 nm. The obtained porous electrode base material is made of polymethacrylic acid in which short carbon fibers dispersed by surface observation with a scanning electron microscope are joined by carbon made into carbonized carbon, and the void size in the carbonized resin is used. It was about 600 to 700 nm depending on the average particle diameter of the methyl particles, and it was confirmed that it was larger than that in Example 1. Moreover, the gas permeability, thickness, and penetration direction resistance were also good results. The evaluation results are shown in Table 1.
（実施例３）
ポリメタクリル酸メチル粒子の平均粒子径を１６３ｎｍとしたこと以外は実施例１と同様にして多孔質電極基材を得た。得られた多孔質電極基材は、走査型電子顕微鏡による表面観察により分散した炭素短繊維同士が、炭多孔質化した炭素によって接合されており、炭化樹脂中の空隙サイズが用いたポリメタクリル酸メチル粒子の平均粒子径に依存して約２００〜２５０ｎｍであり、実施例１と比較して小さくなっていることが確認できた。また、ガス透気度、厚み、貫通方向抵抗もそれぞれ良好な結果であった。評価結果を表１に示した。
(Example 3)
A porous electrode substrate was obtained in the same manner as in Example 1 except that the average particle diameter of the polymethyl methacrylate particles was 163 nm. The obtained porous electrode base material is made of polymethacrylic acid in which short carbon fibers dispersed by surface observation with a scanning electron microscope are joined by carbon made into carbonized carbon, and the void size in the carbonized resin is used. It was about 200 to 250 nm depending on the average particle diameter of the methyl particles, and it was confirmed that it was smaller than that of Example 1. Moreover, the gas permeability, thickness, and penetration direction resistance were also good results. The evaluation results are shown in Table 1.
（実施例４）
ポリメタクリル酸メチル粒子の平均粒子径を７６ｎｍとしたこと以外は実施例１と同様にして多孔質電極基材を得た。得られた多孔質電極基材は、走査型電子顕微鏡による表面観察により分散した炭素短繊維同士が、炭多孔質化した炭素によって接合されており、炭化樹脂中の空隙サイズが用いたポリメタクリル酸メチル粒子の平均粒子径に依存して約８０〜１２０ｎｍであり、実施例３と比較してさらに小さくなっていることが確認できた。また、ガス透気度、厚み、貫通方向抵抗もそれぞれ良好な結果であった。評価結果を表１に示した。
Example 4
A porous electrode substrate was obtained in the same manner as in Example 1 except that the average particle size of the polymethyl methacrylate particles was 76 nm. The obtained porous electrode base material is made of polymethacrylic acid in which short carbon fibers dispersed by surface observation with a scanning electron microscope are joined by carbon made into carbonized carbon, and the void size in the carbonized resin is used. It was about 80 to 120 nm depending on the average particle diameter of the methyl particles, and it was confirmed that it was smaller than that in Example 3. Moreover, the gas permeability, thickness, and penetration direction resistance were also good results. The evaluation results are shown in Table 1.
（実施例５）
平均粒子径２３３ｎｍの単分散性の高いポリメタクリル酸メチル粒子を１０質量％含む水分散液に浸し、室温にて８時間乾燥させることによって、目付けが６４ｇ／ｍ２のポリメタクリル酸メチル粒子が付与され前駆体シートを得たこと以外は実施例１と同様にして多孔質電極基材を得た。得られた多孔質電極基材は、走査型電子顕微鏡による表面観察により分散した炭素短繊維同士が、炭多孔質化した炭素によって接合されており、炭化樹脂中の空隙サイズが用いたポリメタクリル酸メチル粒子の平均粒子径に依存して約２５０〜３００ｎｍであり、実施例１と比較して同様であるが、走査型電子顕微鏡による表面観察によって観察される空隙が減少していることが確認できた。また、ガス透気度、厚み、貫通方向抵抗もそれぞれ良好な結果であった。評価結果を表１に示した。
(Example 5)
By immersing in an aqueous dispersion containing 10% by mass of polymethyl methacrylate particles having an average particle size of 233 nm and high monodispersity, and drying at room temperature for 8 hours, polymethyl methacrylate particles having a basis weight of 64 g / m 2 are imparted. Then, a porous electrode substrate was obtained in the same manner as in Example 1 except that the precursor sheet was obtained. The obtained porous electrode base material is made of polymethacrylic acid in which short carbon fibers dispersed by surface observation with a scanning electron microscope are joined by carbon made into carbonized carbon, and the void size in the carbonized resin is used. Depending on the average particle diameter of the methyl particles, it is about 250 to 300 nm, which is the same as in Example 1, but it can be confirmed that the voids observed by surface observation with a scanning electron microscope are reduced. It was. Moreover, the gas permeability, thickness, and penetration direction resistance were also good results. The evaluation results are shown in Table 1.
（実施例６）
加熱加圧した前駆体シートをバッチ熱風炉で、空気中、２５０℃の条件下で１時間酸化処理した後、２０００℃の条件下で１時間炭素化したこと以外は実施例５と同様にして多孔質電極基材を得た。得られた多孔質電極基材は、走査型電子顕微鏡による表面観察により分散した炭素短繊維同士が、炭多孔質化した炭素によって接合されており、炭化樹脂中の空隙サイズが用いたポリテトラフルオロエチレン粒子の平均粒子径に依存して約２００〜２５０ｎｍであり、実施例６と比較して小さくなっていることが確認できた。また、ガス透気度、厚み、貫通方向抵抗もそれぞれ良好な結果であった。評価結果を表１に示した。
(Example 6)
Except that the heated and pressurized precursor sheet was oxidized in a batch hot air oven in air at 250 ° C. for 1 hour and then carbonized at 2000 ° C. for 1 hour, in the same manner as in Example 5. A porous electrode substrate was obtained. In the obtained porous electrode base material, short carbon fibers dispersed by surface observation with a scanning electron microscope are joined together by carbon made into carbonized carbon, and the pore size in the carbonized resin is used as polytetrafluorocarbon. It was about 200 to 250 nm depending on the average particle diameter of the ethylene particles, and it was confirmed that it was smaller than that of Example 6. Moreover, the gas permeability, thickness, and penetration direction resistance were also good results. The evaluation results are shown in Table 1.
（実施例７）
平均粒子径５５０ｎｍの単分散性の高いポリメタクリル酸メチル粒子を１０質量％と平均粒子径１６３ｎｍの単分散性の高いポリメタクリル酸メチル粒子を１０質量％含む分散液を用いたこと以外は実施例１と同様にして多孔質電極基材を得た。なお、得られた多孔質電極基材の走査型電子顕微鏡による表面観察写真を図２に示す。得られた多孔質電極基材は、走査型電子顕微鏡による表面観察により分散した炭素短繊維同士が、炭多孔質化した炭素によって接合されており、炭化樹脂中の空隙サイズが用いたポリメタクリル酸メチル粒子の平均粒子径に依存して約６００〜７００ｎｍと約２００〜２５０ｎｍの空隙サイズが異なる２種の空隙が形成されていることが確認できた。また、ガス透気度、厚み、貫通方向抵抗もそれぞれ良好な結果であった。評価結果を表１に示した。
(Example 7)
Except for using a dispersion containing 10% by mass of polymethyl methacrylate particles having an average particle size of 550 nm and high monodispersity and 10% by mass of polymethyl methacrylate particles having an average particle size of 163 nm and high monodispersity. In the same manner as in Example 1, a porous electrode substrate was obtained. In addition, the surface observation photograph by the scanning electron microscope of the obtained porous electrode base material is shown in FIG. The obtained porous electrode base material is made of polymethacrylic acid in which short carbon fibers dispersed by surface observation with a scanning electron microscope are joined by carbon made into carbonized carbon, and the void size in the carbonized resin is used. It was confirmed that two types of voids having different pore sizes of about 600 to 700 nm and about 200 to 250 nm were formed depending on the average particle diameter of the methyl particles. Moreover, the gas permeability, thickness, and penetration direction resistance were also good results. The evaluation results are shown in Table 1.
（実施例８）
ポリメタクリル酸メチル粒子の平均粒子径を２３３ｎｍと７６ｎｍとしたこと以外は実施例７と同様にして多孔質電極基材を得た。得られた多孔質電極基材は、走査型電子顕微鏡による表面観察により分散した炭素短繊維同士が、炭多孔質化した炭素によって接合されており、炭化樹脂中の空隙サイズが用いたポリメタクリル酸メチル粒子の平均粒子径に依存して約２５０〜３００ｎｍと約８０〜１２０ｎｍの空隙サイズが異なる２種の空隙が形成されていることが確認できた。また、ガス透気度、厚み、貫通方向抵抗もそれぞれ良好な結果であった。評価結果を表１に示した。
(Example 8)
A porous electrode substrate was obtained in the same manner as in Example 7 except that the average particle diameter of the polymethyl methacrylate particles was 233 nm and 76 nm. The obtained porous electrode base material is made of polymethacrylic acid in which short carbon fibers dispersed by surface observation with a scanning electron microscope are joined by carbon made into carbonized carbon, and the void size in the carbonized resin is used. It was confirmed that two types of voids having different void sizes of about 250 to 300 nm and about 80 to 120 nm were formed depending on the average particle diameter of the methyl particles. Moreover, the gas permeability, thickness, and penetration direction resistance were also good results. The evaluation results are shown in Table 1.
（実施例９）
フェノール樹脂組成物（大日本インキ化学株式会社製フェノライトＪ−３２５）を１３質量％含むフェノール樹脂組成物のメタノール溶液１００質量部に対し、平均粒子径２３３ｎｍの単分散性の高いポリメタクリル酸メチル粒子を４０質量％含む水分散液を３３質量部となるようにしたフェノール樹脂組成物とポリメタクリル酸メチル粒子の混合分散液を含浸させ、室温にて８時間乾燥させることによって、目付けが５２ｇ／ｍ２のポリメタクリル酸メチル粒子が付与されたフェノール樹脂組成物含浸前駆体シートを得たこと以外は実施例１と同様にして多孔質電極基材を得た。得られた多孔質電極基材は、走査型電子顕微鏡による表面観察により分散した炭素短繊維同士が、炭多孔質化した炭素によって接合されており、空隙サイズが用いたポリメタクリル酸メチル粒子の平均粒子径に依存して約２５０〜３００ｎｍであることが確認できた。また、ガス透気度、厚み、貫通方向抵抗がそれぞれ良好な結果であった。評価結果を表１に示した。
Example 9
Polymethylmethacrylate having a high monodispersity with an average particle diameter of 233 nm with respect to 100 parts by mass of a methanol solution of a phenolic resin composition containing 13% by mass of a phenolic resin composition (Phenolite J-325 manufactured by Dainippon Ink and Chemicals, Inc.) By impregnating a mixed dispersion of a phenol resin composition and polymethyl methacrylate particles in which an aqueous dispersion containing 40% by mass of particles was 33 parts by mass and drying at room temperature for 8 hours, the basis weight was 52 g / A porous electrode base material was obtained in the same manner as in Example 1 except that a phenol resin composition-impregnated precursor sheet provided with m 2 polymethyl methacrylate particles was obtained. In the obtained porous electrode base material, carbon short fibers dispersed by surface observation with a scanning electron microscope are joined together by carbon made into carbonized carbon, and the average of polymethyl methacrylate particles having a void size is used. It was confirmed that the thickness was about 250 to 300 nm depending on the particle diameter. Moreover, the gas permeability, thickness, and penetration direction resistance were good results, respectively. The evaluation results are shown in Table 1.
（比較例１）
ポリメタクリル酸メチル粒子を包含させず、フェノール樹脂組成物（大日本インキ化学株式会社製フェノライトＪ−３２５）を１３質量％含むフェノール樹脂組成物のメタノール溶液を含浸させ、室温にて８時間乾燥させることによって、目付けが５２ｇ／ｍ２のフェノール樹脂組成物のみが付与された前駆体シートを得たこと以外は実施例１と同様にして多孔質電極基材を得た。得られた多孔質電極基材はガス透気度、厚み、貫通方向抵抗はそれぞれ良好な結果であったが、走査型電子顕微鏡による表面観察により分散した炭素短繊維同士が、炭多孔質化していない炭素によって接合されていることが確認できた。評価結果を表１に示した。
(Comparative Example 1)
Impregnated with a methanol solution of a phenol resin composition containing 13% by mass of a phenol resin composition (Phenolite J-325 manufactured by Dainippon Ink & Chemicals, Inc.) without including polymethyl methacrylate particles, and dried at room temperature for 8 hours. Thus, a porous electrode substrate was obtained in the same manner as in Example 1 except that a precursor sheet provided with only a phenol resin composition having a basis weight of 52 g / m 2 was obtained. The obtained porous electrode substrate had good results in gas permeability, thickness, and penetration resistance, but the carbon short fibers dispersed by surface observation with a scanning electron microscope were made carbon porous. It was confirmed that they were joined by no carbon. The evaluation results are shown in Table 1.
（実施例１０）
（１）膜−電極接合体（ＭＥＡ）の作製
実施例１で得られた多孔質電極基材をカソード用、アノード用に２組用意した。両面に触媒担持カーボン（触媒：Ｐｔ、触媒担持量：５０質量％）からなる触媒層（触媒層面積：２５ｃｍ２、Ｐｔ付着量：０．３ｍｇ／ｃｍ２）を形成したパーフルオロスルホン酸系の高分子電解質膜（膜厚：３０μｍ）を、カソード用、アノード用の多孔質電極基材で挟持し、これらを接合してＭＥＡを得た。
(Example 10)
(1) Production of membrane-electrode assembly (MEA) Two sets of the porous electrode base material obtained in Example 1 were prepared for the cathode and the anode. Perfluorosulfonic acid based catalyst in which a catalyst layer (catalyst layer area: 25 cm 2 , Pt adhesion amount: 0.3 mg / cm 2 ) composed of catalyst-supported carbon (catalyst: Pt, catalyst support amount: 50% by mass) is formed on both surfaces. A polymer electrolyte membrane (film thickness: 30 μm) was sandwiched between porous electrode substrates for cathode and anode, and these were joined to obtain MEA.
（２）ＭＥＡの燃料電池特性評価
前記（１）で作製したＭＥＡを、蛇腹状のガス流路を有する２枚のカーボンセパレーターによって挟み、固体高分子型燃料電池（単セル）を形成した。
この単セルの電流密度−電圧特性を測定することによって、燃料電池特性評価を行った。燃料ガスとしては水素ガスを用い、酸化ガスとしては空気を用いた。セル温度を８０℃、燃料ガス利用率を６０％、酸化ガス利用率を４０％とした。また、ガス加湿はバブラーにそれぞれ燃料ガスと酸化ガスを通すことによって行った。
加湿器温度８０℃、電流密度が０．８Ａ／ｃｍ２のときの燃料電池セルのセル電圧が０．６４２Ｖであった。
また、加湿器温度６０℃、電流密度が０．８Ａ／ｃｍ２のときの燃料電池セルのセル電圧が０．６１３Ｖと良好な特性を示し、加湿条件の変動によっても電池性能の変動が少ない高い水分管理機能を有していることが確認できた。
(2) Evaluation of MEA Fuel Cell Characteristics The MEA produced in (1) was sandwiched between two carbon separators having bellows-like gas flow paths to form a polymer electrolyte fuel cell (single cell).
The fuel cell characteristics were evaluated by measuring the current density-voltage characteristics of this single cell. Hydrogen gas was used as the fuel gas, and air was used as the oxidizing gas. The cell temperature was 80 ° C., the fuel gas utilization rate was 60%, and the oxidizing gas utilization rate was 40%. Gas humidification was performed by passing fuel gas and oxidizing gas through a bubbler.
The cell voltage of the fuel cell when the humidifier temperature was 80 ° C. and the current density was 0.8 A / cm 2 was 0.642V.
In addition, the cell voltage of the fuel cell when the humidifier temperature is 60 ° C. and the current density is 0.8 A / cm 2 is 0.613 V, which shows a good characteristic, and the fluctuation of the battery performance is small due to the fluctuation of the humidification condition. It was confirmed that it had a moisture management function.
（比較例２）
比較例１の多孔質電極基材を用いたこと以外は、実施例１０と同様にして燃料電池評価を行った。
加湿器温度８０℃、電流密度が０．８Ａ／ｃｍ２のときの燃料電池セルのセル電圧が０．６４０Ｖであった。
また、加湿器温度６０℃、電流密度が０．８Ａ／ｃｍ２のときの燃料電池セルのセル電圧が０．５１６Ｖと燃料電池セル内での保水性の低下による性能低下が顕著に見られた。
(Comparative Example 2)
The fuel cell was evaluated in the same manner as in Example 10 except that the porous electrode substrate of Comparative Example 1 was used.
The cell voltage of the fuel cell when the humidifier temperature was 80 ° C. and the current density was 0.8 A / cm 2 was 0.640V.
Further, when the humidifier temperature is 60 ° C. and the current density is 0.8 A / cm 2 , the cell voltage of the fuel cell is 0.516 V, and the performance degradation due to the decrease in water retention in the fuel cell is noticeable. .
Claims (9)
（Ａ）炭素短繊維とバインダー短繊維とを、分散し炭素短繊維紙を作製する工程；
（Ｂ）炭素化後の残炭率が１５質量％以下の樹脂からなる平均粒径１０ｎｍ〜２μｍの粒子と炭素化後の残炭率が２０質量％以上の樹脂組成物とを炭素短繊維紙に付与する工程；
（Ｃ）加熱加圧して、前記樹脂組成物を硬化する工程；
（Ｄ）樹脂組成物の硬化物を炭素化すると同時に、前記粒子を熱分解する工程 The manufacturing method of the porous electrode base material which performs the following (A)-(D) processes in order.
(A) A step of dispersing carbon short fibers and binder short fibers to produce carbon short fiber paper;
(B) Carbon short fiber paper comprising particles having an average particle size of 10 nm to 2 μm made of a resin having a carbon residue ratio of 15% by mass or less after carbonization and a resin composition having a carbon residue rate of 20% by mass or more after carbonization. Applying to:
(C) a step of curing the resin composition by heating and pressing;
(D) The step of thermally decomposing the particles simultaneously with carbonizing the cured product of the resin composition
（Ａ）炭素短繊維とバインダー短繊維とを、分散し炭素短繊維紙を作製する工程；
（Ｂ）平均粒径５０〜６００ｎｍのポリメタクリル酸メチル粒子とフェノール樹脂組成物とを炭素短繊維紙に付与する工程；
（Ｃ）加熱加圧してフェノール樹脂組成物を硬化する工程；および
（Ｄ）フェノール樹脂組成物の硬化物を炭素化すると同時に、ポリメタクリル酸メチル粒子を熱分解する工程 The manufacturing method of the porous electrode base material of Claim 1 which performs the following processes in order.
(A) A step of dispersing carbon short fibers and binder short fibers to produce carbon short fiber paper;
(B) A step of imparting polymethyl methacrylate particles having an average particle diameter of 50 to 600 nm and a phenol resin composition to carbon short fiber paper;
(C) a step of curing the phenol resin composition by heating and pressurizing; and (D) a step of carbonizing the cured product of the phenol resin composition and simultaneously decomposing the polymethyl methacrylate particles.
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| JP2018147595A (en) * | 2017-03-01 | 2018-09-20 | 三菱ケミカル株式会社 | Electrode for redox flow battery and method of manufacturing the same, and redox flow battery |
| CN108675825A (en) * | 2018-06-14 | 2018-10-19 | 北京蓝海黑石科技有限公司 | A kind of porous carbon anode material and its preparation method and application |
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| JPH05251088A (en) * | 1992-03-06 | 1993-09-28 | Oji Paper Co Ltd | Manufacture of porous carbon electrode plate for fuel cell |
| JPH082979A (en) * | 1993-11-01 | 1996-01-09 | Osaka Gas Co Ltd | Porous carbon material and its production |
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| JPH02106876A (en) * | 1988-10-14 | 1990-04-18 | Kureha Chem Ind Co Ltd | Manufacture of porous carbon electrode base for fuel cell |
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