JP6834524B2 - Electrode-forming compositions, electrodes, and microbial fuel cells used in microbial fuel cells - Google Patents

Description

The present invention relates to an electrode-forming composition, an electrode, and a microbial fuel cell used in a microbial fuel cell.

In recent years, the development of microbial fuel cells using the mechanism of fuel cells has been promoted. This is a power generation method that recovers electrons generated when organic matter is decomposed by microorganisms and uses them as electrical energy. For example, when it is used for purifying domestic wastewater, it is expected as a water treatment method that can reduce energy consumption because decomposition treatment and power generation can be performed in parallel.

The shape of the microbial fuel cell is known to be a two-tank type or a one-tank type. It is common that electrons generated from the decomposition reaction by microorganisms at the anode pass through an external circuit and are consumed in the reduction reaction at the cathode. In the two-tank type, both poles are separated by a partition wall such as an ion exchange membrane, and an oxidizing agent such as oxygen or potassium ferricyanide is reacted at the cathode. On the other hand, the one-tank type has no partition wall, and an air cathode that directly flows in and reacts with oxygen in the atmosphere is installed in the same tank as the anode.

Regardless of which method is used, for example, assuming water treatment, the electrode can withstand water pressure without peeling off and is expected to operate for a long period of time. Therefore, it can be used as a binder for binding electrode members such as catalysts and conductive materials. Is required to have strong adhesion. Further, in order to obtain high power generation performance, it is necessary to select an electrode member that does not interfere with a microbial reaction or a catalytic reaction, particularly a resin, and it is desirable that the total amount of the resin is small.

At present, Nafion (registered trademark) manufactured by DuPont is often used as a resin for forming electrodes, and its proton conductivity ensures adhesion without inhibiting a catalytic reaction at the cathode. However, its performance is still insufficient, and it is also mentioned that it is expensive as a problem other than the above, and diligent research is being carried out for improvement (Non-Patent Documents 1 and 2).

Environ. Sci. Technol. (2006), 40, 364-369 Journal of Power Sources (2012), 218, 100-105

An object of the present invention is to provide an electrode-forming composition for producing an electrode for a microbial fuel cell, which has excellent adhesion between base materials and materials and excellent power generation characteristics, and an inexpensive electrode-forming composition. That is.

The present inventors have arrived at the present invention as a result of repeated diligent studies to solve the above-mentioned problems. That is, the present invention relates to a composition for forming a microbial fuel cell electrode containing a conductive material and / or an oxygen reduction catalyst and aqueous resin fine particles.

The present invention also relates to the above-mentioned composition for forming a microbial fuel cell electrode in which the aqueous resin fine particles contain an acrylic emulsion polymer.

The present invention also relates to the above-mentioned composition for forming a microbial fuel cell electrode in which the conductive material is a carbon material.

The present invention also relates to the above-mentioned composition for forming a microbial fuel cell electrode, wherein the oxygen reduction catalyst is one or more selected from the group consisting of a noble metal catalyst, a base metal oxide catalyst, a carbon catalyst and activated carbon.

The present invention further relates to the above-mentioned composition for forming a microbial fuel cell electrode containing an aqueous liquid medium.

The present invention also relates to an electrode for a microbial fuel cell, which comprises using the above-mentioned composition for forming a microbial fuel cell electrode.

The composition according to any one of the above, which is installed on any of the liquid surface, the liquid surface, the side surface, and the bottom surface of the microbial fuel cell, one surface of which is in contact with air outside the tank and the back surface of which is in contact with an electrolytic solution. The present invention relates to an electrode for a microbial fuel cell, which comprises using.

The present invention also relates to a microbial fuel cell, which comprises using the above-mentioned electrode for a microbial fuel cell.

According to the present invention, the composition for forming a microbial fuel cell electrode in which aqueous resin fine particles are dispersed together with a conductive material and / or an oxygen reduction catalyst is excellent in adhesion between particles and with a base material when a coating film is formed. , A high-strength microbial fuel cell electrode can be provided.

Further, since the binding of the aqueous resin fine particles with the conductive material and / or the oxygen reduction catalyst is by point contact, for example, in the case of a catalyst having an interface as a reaction field, it is difficult to inhibit the catalytic reaction. Further, since the adhesiveness is excellent, a small amount of resin is required, and as a result, the resistance due to the resin can be reduced. That is, by using a composition for forming a microbial fuel cell electrode containing a conductive material and / or an oxygen reduction catalyst and aqueous resin fine particles, a microbial fuel cell having excellent power generation performance can be provided.

Further, since the aqueous resin fine particles can be produced at low cost depending on the constituent monomers, the production cost of the composition for forming a microbial fuel cell electrode can be reduced.

<Mixed material ink for microbial fuel cells>
The composition for forming an electrode for a microbial fuel cell (hereinafter, a mixture ink) of the present invention contains at least a conductive material and / or an oxygen reduction catalyst, aqueous resin fine particles (A), and an aqueous liquid medium. .. The proportions of the conductive material and / or the oxygen reduction catalyst, the aqueous resin fine particles, and the aqueous liquid medium are not particularly limited and may be appropriately selected within a wide range.

<Aqueous resin fine particles>
Aqueous resin fine particles are those in which the resin does not dissolve in water and exists in the form of fine particles, and the aqueous dispersion is generally also called an aqueous emulsion and can be used in the present invention.
Emulsions used include (meth) acrylic emulsions, nitrile emulsions, urethane emulsions, diene emulsions (styrene-butadiene rubber (SBR), etc.), fluorine emulsions (polyvinylidene fluoride (PVDF) and polytetrafluoroethylene). (PTFE), etc.) and the like. Unlike the water-soluble polymer, the emulsion preferably has excellent bondability and flexibility (flexibility of the film) between particles.
(Particle structure of aqueous resin fine particles)
Further, the particle structure of the aqueous resin fine particles used in the present invention may be a multilayer structure, so-called core-shell particles. For example, by localizing a resin in which a monomer having a functional group is mainly polymerized in the core portion or the shell portion, or by providing a difference in Tg and composition between the core and the shell, curability and drying are performed. It is possible to improve the property, film forming property, and mechanical strength of the binder.

(Particle size of water-based resin fine particles)
The average particle size of the aqueous resin fine particles used in the present invention is preferably 10 to 500 nm, more preferably 10 to 300 nm, from the viewpoint of binding properties and particle stability. Further, if a large amount of coarse particles exceeding 1 μm is contained, the stability of the particles is impaired, so that the amount of coarse particles exceeding 1 μm is preferably 5% or less at most. The average particle size in the present invention represents the volume average particle size and can be measured by a dynamic light scattering method.

The average particle size can be measured by the dynamic light scattering method as follows. The crosslinked resin fine particle dispersion is diluted 200 to 1000 times with water depending on the solid content. Approximately 5 ml of the diluted solution is injected into a cell of a measuring device [Microtrac manufactured by Nikkiso Co., Ltd.], and the measurement is performed after inputting the refractive index conditions of the solvent (water in the present invention) and the resin according to the sample. The peak of the volumetric particle size distribution data (histogram) obtained at this time is taken as the average particle size of the present invention.

<(Meta) acrylic emulsion>
Next, the (meth) acrylic emulsion will be described. The (meth) acrylic emulsion is an emulsion polymer containing 10 parts by mass or more of a monomer having a (meth) acryloyl group, preferably 20 parts by mass or more, and more preferably 30 parts by mass or more. It is good. Since the monomer having an acryloyl group has excellent reactivity, resin fine particles can be produced relatively easily. Further, the coating film made of the (meth) acrylic emulsion is excellent in adhesion and flexibility.

When a (meth) acrylic emulsion is used, it is preferable to contain crosslinked resin fine particles described below. The crosslinked resin fine particles indicate resin fine particles having an internal crosslinked structure (three-dimensional crosslinked structure), and it is important that the particles are crosslinked inside the particles. The cross-linked resin fine particles have a cross-linked structure, so that the electrolytic solution elution resistance can be ensured, and the effect can be enhanced by adjusting the cross-linking inside the particles. Further, when the crosslinked resin fine particles contain a specific functional group, it is possible to contribute to the adhesion to the base material or other electrode constituent materials. Furthermore, by adjusting the crosslinked structure and the amount of functional groups, it is possible to obtain a mixture ink having excellent durability of the microbial fuel cell.
In addition, cross-linking between particles (cross-linking between particles) can be used in combination for cross-linking, but in this case, since a cross-linking agent is added later, the cross-linking agent component leaks into the electrolytic solution or when the electrode is manufactured. There may be variations. Therefore, it is necessary to use the cross-linking agent to the extent that the electrolytic solution resistance is not impaired.

The crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention are obtained by emulsion polymerization of an ethylenically unsaturated monomer in water with a radical polymerization initiator in the presence of a surfactant. Resin fine particles to be obtained. The (meth) acrylic emulsion preferably used in the present invention is preferably obtained by emulsion polymerization of an ethylenically unsaturated monomer containing the following monomers (C1) and (C2) in the following proportions.
(C1) From the group consisting of an ethylenically unsaturated monomer (c1) having a monofunctional or polyfunctional alkoxysilyl group and a monomer (c2) having two or more ethylenically unsaturated groups in one molecule. At least one monomer selected: 0.1-5% by weight
(C2) Ethylene unsaturated monomer (c3) other than the monomers (c1) to (c2): 95 to 99.9% by mass.
(However, the total of the above (c1) to (c3) is 100% by mass)

Of the ethylenically unsaturated monomers constituting the crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention, (c1) and (c3) are contained in one molecule unless otherwise specified. It indicates a monomer having one ethylenically unsaturated group.

<About the monomer group (C1)>
The functional groups (alkoxysilyl group, ethylenically unsaturated group) of the monomer contained in the monomer group (C1) are self-crosslinking reactive functional groups, which mainly perform internal cross-linking during particle synthesis. Has the effect of forming. Sufficient internal cross-linking of particles can improve the electrolyte resistance. Therefore, crosslinked resin fine particles can be obtained by using the monomer contained in the monomer group (C1). In addition, the electrolytic solution resistance can be improved by sufficiently performing particle cross-linking.

Examples of the monomer (c1) having one ethylenically unsaturated group and an alkoxysilyl group in one molecule include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-. Methacryloxypropyltributoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropylmethyl Examples thereof include dimethoxysilane, γ-methacryloxymethyltrimethoxysilane, γ-acryloxymethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, and vinylmethyldimethoxysilane.

Examples of the monomer (c2) having two or more ethylenically unsaturated groups in one molecule include allyl (meth) acrylate, 1-methylallyl (meth) acrylate, and 2-methylallyl (meth) acrylate. , (Meta) acrylate 1-butenyl, (meth) acrylate 2-butenyl, (meth) acrylate 3-butenyl, (meth) acrylate 1,3-methyl-3-butenyl, (meth) acrylate 2- Chlorallyl, 3-chloroallyl (meth) acrylate, o-allylphenyl (meth) acrylate, 2- (allyloxy) ethyl (meth) acrylate, allyllactyl (meth) acrylate, citronellyl (meth) acrylate, (meth) Geranyl acrylate, Loginyl (meth) acrylate, Synamyl (meth) acrylate, diallyl maleate, diallyl itaconic acid, vinyl (meth) vinyl acrylate, vinyl crotonate, vinyl oleate, vinyl linolenate, (meth) acrylic acid (Meta) acrylic acid esters containing ethylenically unsaturated groups such as 2- (2'-vinyloxyethoxy) ethyl; ethylene glycol di (meth) acrylic acid, triethylene glycol di (meth) acrylic acid, di (meth) Tetraethylene glycol acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,1,1-trishydroxymethylethane diacrylic acid, 1,1,1-trishydroxymethyl triacrylate Polyfunctional (meth) acrylic acid esters such as ethane, 1,1,1-trishydroxymethylpropanetriacrylic acid; divinyls such as divinylbenzene and divinyl adipate; diallyl isophthalate, diallyl phthalate, diallyl maleate, etc. Diaryls and the like can be mentioned.

The alkoxysilyl group or ethylenically unsaturated group in the monomer (c1) or the monomer (c2) is mainly intended to self-condensate or polymerize during polymerization to introduce a crosslinked structure into the particles. However, a part of it may remain inside or on the surface of the particles even after polymerization. The remaining alkoxysilyl group or ethylenically unsaturated group contributes to the interparticle crosslinking of the binder composition. In particular, the alkoxysilyl group is preferable because it has an effect of contributing to the improvement of adhesion to the substrate.

In the present invention, the monomer contained in the monomer group (C1) is used in an amount of 0.1 to 5% by mass in the entire ethylenically unsaturated monomer (total 100% by mass) used for emulsion polymerization. It is characterized by that. It is preferably 0.5 to 3% by mass.

<About the monomer group (C2)>
The crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention include the above-mentioned monomer (c1) having one ethylenically unsaturated group and an alkoxysilyl group in one molecule. In addition to the monomer (c2) having two or more ethylenically unsaturated groups in one molecule, the monomer group (C2) is ethylenically other than the monomers (c1) and (c2). It can be obtained by simultaneously emulsifying and polymerizing a monomer (c3) having an unsaturated group.

The monomer (c3) is not particularly limited as long as it is a monomer other than the monomers (c1) and (c2) and has an ethylenically unsaturated group.
Monomer (c4) having one ethylenically unsaturated group in one molecule and a monofunctional or polyfunctional epoxy group, one ethylenically unsaturated group in one molecule, and a monofunctional or polyfunctional amide group At least one monomer selected from the group consisting of a monomer (c5) having and, and a monomer (c6) having one ethylenically unsaturated group in one molecule and a monofunctional or polyfunctional hydroxyl group. The body and the monomer (c7) having an ethylenically unsaturated group other than the monomers (c1), (c2), (c4) to (c6) can be used.
By using the monomers (c4) to (c6), an epoxy group, an amide group, or a hydroxyl group can be left in or on the surface of the crosslinked resin fine particles, whereby the adhesion of the base material and the like can be improved. Physical properties can be improved. The functional groups of the monomers (c4) to (c6) tend to remain inside or on the surface of the particles even after particle synthesis, and even a small amount has a large adhesive effect to the substrate. In addition, a part of the crosslinks may be used in the crosslinking reaction, and by adjusting the degree of crosslinking of these functional groups, the electrolytic solution resistance and the adhesion can be balanced.

Examples of the monomer (c4) having one ethylenically unsaturated group and a monofunctional or polyfunctional epoxy group in one molecule include glycidyl (meth) acrylate and 3,4-epoxycyclohexyl (meth) acrylate. And so on.

Examples of the monomer (c5) having one ethylenically unsaturated group and a monofunctional or polyfunctional amide group in one molecule include a primary amide group-containing ethylenically unsaturated mono such as (meth) acrylamide. Quantities; Alkyrol (meth) acrylamides such as N-methylolacrylamide, N, N-di (methylol) acrylamide, N-methylol-N-methoxymethyl (meth) acrylamide; N-methoxymethyl- (meth) acrylamide, Monoalkoxy (meth) acrylamides such as N-ethoxymethyl- (meth) acrylamide, N-propoxymethyl- (meth) acrylamide, N-butoxymethyl- (meth) acrylamide, N-pentoxymethyl- (meth) acrylamide; N, N-di (methoxymethyl) acrylamide, N-ethoxymethyl-N-methoxymethyl metaacrylamide, N, N-di (ethoxymethyl) acrylamide, N-ethoxymethyl-N-propoxymethyl metaacrylamide, N, N- Di (propoxymethyl) acrylamide, N-butoxymethyl-N- (propoxymethyl) metaacrylamide, N, N-di (butoxymethyl) acrylamide, N-butoxymethyl-N- (methoxymethyl) metaacrylamide, N, N- Dialkoxy (meth) acrylamides such as di (pentoxymethyl) acrylamide, N-methoxymethyl-N- (pentoxymethyl) metaacrylamide; N, N-dimethylaminopropylacrylamide, N, N-diethylaminopropylacrylamide, etc. Dialkylamino (meth) acrylamides; dialkyl (meth) acrylamides such as N, N-dimethylacrylamide, N, N-diethylacrylamide; keto group-containing (meth) acrylamides such as diacetone (meth) acrylamide. ..

Examples of the monomer (c6) having one ethylenically unsaturated group and a monofunctional or polyfunctional hydroxyl group in one molecule include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate. , 4-Hydroxybutyl (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid, glycerol mono (meth) acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, allyl Alcohol etc. can be mentioned.

Some of the functional groups of the monomers contained in the monomers (c4) to (c6) may react during particle polymerization and be used for intraparticle cross-linking. In the present invention, the monomers contained in the monomers (c4) to (c6) are 0.1 to 20% by mass in the entire ethylenically unsaturated monomer (100% by mass in total) used for emulsion polymerization. It is characterized by being used. It is preferably 1 to 15% by mass, and particularly preferably 2 to 10% by mass.

The monomer (c7) is not particularly limited as long as it is a monomer other than the monomers (c1), (c2), (c4) to (c6) and has an ethylenically unsaturated group. For example, a monomer (c8) having one ethylenically unsaturated group in one molecule and an alkyl group having 8 to 18 carbon atoms, one ethylenically unsaturated group in one molecule, and a cyclic structure. Examples thereof include the monomer (c9) having. When the monomer (c8) and / or the monomer (c9) is used for emulsion polymerization as the monomer (c7), the monomer (c7) contains other monomers. (May be said), the entire monomer in which the monomers (c8) and (c9) have an ethylenically unsaturated group ((c1), (c2), (c4) to (c6) and (c7)) It is preferable that the total content is 30 to 95% by mass. It is preferable to use the monomer (c8) or the monomer (c9) because it is excellent in particle stability and electrolytic solution resistance during particle synthesis.

Examples of the monomer (c8) having one ethylenically unsaturated group and an alkyl group having 8 to 18 carbon atoms in one molecule include 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and myristyl. Examples thereof include (meth) acrylate, cetyl (meth) acrylate, and stearyl (meth) acrylate.

Examples of the monomer (c9) having one ethylenically unsaturated group in one molecule and a cyclic structure include an alicyclic ethylenically unsaturated monomer and an aromatic ethylenically unsaturated monomer. Be done. Examples of the alicyclic ethylenically unsaturated monomer include cyclohexyl (meth) acrylate and isovonyl (meth) acrylate, and examples of the aromatic ethylenically unsaturated monomer include benzyl (meth) acrylate. , Phenoxyethyl (meth) acrylate, styrene, α-methylstyrene, 2-methylstyrene, chlorostyrene, allylbenzene, ethynylbenzene and the like.

Examples of the monomer (c7) other than the above-mentioned monomer (c8) and monomer (c9) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n-butyl (meth). ) Alkyl group-containing ethylenically unsaturated monomers such as acrylate, pentyl (meth) acrylate, and heptyl (meth) acrylate; nitrile group-containing ethylenically unsaturated monomers such as (meth) acrylonitrile; perfluoromethylmethyl (meth). ) Acrylate, perfluoroethylmethyl (meth) acrylate, 2-perfluorobutylethyl (meth) acrylate, 2-perfluorohexyl ethyl (meth) acrylate, 2-perfluorooctylethyl (meth) acrylate, 2-perfluoroiso Nonylethyl (meth) acrylate, 2-perfluorononylethyl (meth) acrylate, 2-perfluorodecylethyl (meth) acrylate, perfluoropropylpropyl (meth) acrylate, perfluorooctylpropyl (meth) acrylate, perfluorooctyl Perfluoroalkyl group-containing ethylenically unsaturated monomers having 1 to 20 carbon atoms such as amyl (meth) acrylate and perfluorooctylundecyl (meth) acrylate; perfluorobutylethylene and perfluorohexyl. Perfluoroalkyl such as ethylene, perfluorooctylethylene, perfluorodecylethylene, perfluoroalkyl group-containing ethylenically unsaturated compounds such as alkylenes; polyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (Meta) acrylate, propoxypolyethylene glycol (meth) acrylate, n-butoxypolyethylene glycol (meth) acrylate, n-pentoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxy Polypropylene glycol (meth) acrylate, ethoxypolypropylene glycol (meth) acrylate, propoxypolypropylene glycol (meth) acrylate, n-butoxypolypropylene glycol (meth) acrylate, n-pentoxypolypropylene glycol (meth) acrylate, phenoxypolypolyglyco Le (meth) acrylate, polytetramethylene glycol (meth) acrylate, methoxypolytetramethylene glycol (meth) acrylate, phenoxytetraethylene glycol (meth) acrylate, hexaethylene glycol (meth) acrylate, methoxyhexaethylene glycol (meth) acrylate Ethylene unsaturated compounds having polyether chains such as; ethylenically unsaturated compounds having polyester chains such as lactone-modified (meth) acrylates; dimethylaminoethyl methyl chloride salt (meth) acrylate, trimethyl-3- (1-) (Meta) acrylamide-1,1-dimethylpropyl) ammonium chloride, trimethyl-3- (1- (meth) acrylamidepropyl) ammonium chloride, and trimethyl-3- (1- (meth) acrylamide-1,1-dimethylethyl) ) Tethylene unsaturated compounds containing quaternary ammonium bases such as ammonium chloride; vinyl acetate, vinyl butyrate, vinyl propionate, vinyl hexanoate, vinyl caprylate, vinyl laurate, vinyl palmitate, vinyl stearate, etc. Compounds: Vinyl ether-based ethylenically unsaturated monomers such as butyl vinyl ether and ethyl vinyl ether; α-olefin-based ethylenic compounds such as 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene and 1-hexadecene. Unsaturated monomers; allyl monomers such as allyl acetate and allyl cyanide; vinyl monomers such as vinyl cyanide, vinyl cyclohexane and vinyl methyl ketone; ethynyl monomers such as acetylene and ethynyl toluene. ..

Examples of the monomer (c7) other than the above-mentioned monomer (c8) and monomer (c9) include maleic acid, fumaric acid, itaconic acid, citraconic acid, and alkyl or alkenyl monoesters thereof. , Sulfonic acid β- (meth) acryloxyethyl monoester, isophthalic acid β- (meth) acryloxyethyl monoester, terephthalic acid β- (meth) acryloxyethyl monoester, succinic acid β- (meth) acryloxyethyl Carboxyl group-containing ethylenically unsaturated monomers such as monoesters, acrylic acids, methacrylic acids, crotonic acids and carcinic acids; tertiary butyl group-containing ethylenically unsaturated monomers such as tertiary butyl (meth) acrylates; Sulfonic acid group-containing ethylenically unsaturated monomers such as vinyl sulfonic acid and styrene sulfonic acid; phosphoric acid group-containing ethylenically unsaturated monomers such as (2-hydroxyethyl) methacrylate acid phosphate; diacetone (meth) Keto group-containing ethylenically unsaturated monosyl, such as acrylamide, achlorine, N-vinylformamide, vinylmethyl ketone, vinyl ethyl ketone, acetoacetoxyethyl (meth) acrylate, acetoacetoxypropyl (meth) acrylate, acetoacetoxybutyl (meth) acrylate. Examples thereof include a metric (a monomer having one ethylenically unsaturated group and a keto group in one molecule).

When a keto group-containing ethylenically unsaturated monomer is used as the monomer (c7), a polyfunctional hydrazide compound having two or more hydrazide groups capable of reacting with the keto group as a cross-linking agent is mixed with the binder composition. , A tough coating can be obtained by cross-linking a keto group and a hydrazide group. As a result, it has excellent electrolyte resistance and binding properties.

Further, among the monomers (c7), an ethylenically unsaturated single amount having a carboxyl group, a tertiary butyl group (the tertiary butanol is eliminated by heat to become a carboxyl group), a sulfonic acid group, and a phosphoric acid group. The resin fine particles obtained by copolymerizing the bodies have the effect of improving the physical properties such as the adhesion of the base material by leaving the functional groups in the particles and on the surface even after the polymerization, and at the same time, agglomerate during synthesis. It can be preferably used because it may prevent or maintain the particle stability after synthesis.

Some of the carboxyl group, tert-butyl group, sulfonic acid group, and phosphoric acid group may react during polymerization and be used for in-particle cross-linking. When a monomer containing a carboxyl group, a tertiary butyl group, a sulfonic acid group, and a phosphoric acid group is used, the total ethylenically unsaturated monomer used for emulsion polymerization (total 100% by mass) is 0. It is preferably contained in an amount of 1 to 10% by mass, more preferably 1 to 5% by mass. Furthermore, these functional groups may be used for cross-linking within or between particles by reacting during drying.

For example, the carboxyl group can react with the epoxy group during polymerization and drying to introduce a crosslinked structure into the resin fine particles. Similarly, the tertiary butyl group can react with the epoxy group as described above because the tertiary butyl alcohol is generated and the carboxyl group is formed when heat of a certain temperature or higher is applied.

For these monomers (c7), two or more of the above-mentioned monomers are used in combination in order to adjust the polymerization stability of the particles, the glass transition temperature, the film forming property, and the physical characteristics of the coating film. Can be used. Further, for example, the combined use of (meth) acrylonitrile has the effect of developing rubber elasticity.

<Method for producing crosslinked resin fine particles in (meth) acrylic emulsion preferably used in the present invention>
The crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention are synthesized by a conventionally known emulsion polymerization method.

<Emulsifier used in emulsion polymerization>
As the emulsifier used in the emulsion polymerization in the present invention, conventionally known emulsifiers such as a reactive emulsifier having an ethylenically unsaturated group and a non-reactive emulsifier having no ethylenically unsaturated group can be arbitrarily used. it can.

Reactive emulsifiers having an ethylenically unsaturated group can be further roughly classified into anionic and nonionic nonionic emulsifiers. In particular, when an anionic reactive emulsifier or a nonionic reactive emulsifier having an ethylenically unsaturated group is used, the dispersed particle size of the copolymer becomes finer and the particle size distribution becomes narrower, so that the electrolytic solution resistance is improved. Is preferable. The anionic reactive emulsifier or nonionic reactive emulsifier having an ethylenically unsaturated group may be used alone or in combination of two or more.

Specific examples of anionic reactive emulsifiers having an ethylenically unsaturated group will be illustrated below, but the emulsifiers that can be used in the present invention are not limited to those described below.

As the emulsifier, an alkyl ether type (commercially available products include, for example, Aqualon KH-05, KH-10, KH-20 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ADEKA Corporation Adecaria Soap SR-10N, SR-20N, etc. Latemuru PD-104 manufactured by Kao Corporation, etc.); Sulfocuccinate-based (commercially available products include, for example, Latemuru S-120, S-120A, S-180P, S-180A manufactured by Kao Corporation, Eleminor manufactured by Sanyo Kasei Corporation JS-2, etc.); Alkylphenyl ether type or alkylphenyl ester type (Commercially available products include, for example, Aqualon H-2855A, H-3855B, H-3855C, H-3856, HS-05 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. , HS-10, HS-20, HS-30, ADEKA Corporation Adecaria Soap SDX-222, SDX-223, SDX-232, SDX-233, SDX-259, SE-10N, SE-20N, etc.) (Meta) acrylate sulfate ester type (commercially available products include, for example, Antox MS-60 and MS-2N manufactured by Nippon Emulsifier Co., Ltd., Eleminor RS-30 manufactured by Sanyo Kasei Kogyo Co., Ltd.); Examples of the product include H-3330PL manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ADEKA CORPORATION PP-70 manufactured by ADEKA Corporation, and the like).

Examples of the nonionic reactive emulsifier that can be used in the present invention include alkyl ethers (commercially available products include, for example, ADEKA Corporation ADEKA Adecaria Soap ER-10, ER-20, ER-30, ER-40, etc. Latemul PD-420, PD-430, PD-450, etc. manufactured by Kao Corporation; alkylphenyl ether type or alkylphenyl ester type (commercially available products, for example, Aqualon RN-10, RN- 20, RN-30, RN-50, ADEKA Corporation Adecaria Soap NE-10, NE-20, NE-30, NE-40, etc.); (Meta) acrylate sulfate ester type (commercially available, for example, RMA-564, RMA-568, RMA-1114, etc. manufactured by Nippon Ester Co., Ltd.) and the like.

When the crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention are obtained by emulsion polymerization, an ethylenically unsaturated group is required together with the above-mentioned reactive emulsifier having an ethylenically unsaturated group. A non-reactive emulsifier that does not have the above can be used in combination. Non-reactive emulsifiers can be roughly classified into non-reactive anionic emulsifiers and non-reactive nonionic emulsifiers.

Examples of non-reactive nonionic emulsifiers include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; and polyoxyethylene alkyl such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether. Phenyl ethers; sorbitan higher fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate; polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate; polyoxyethylene monolaurate, Polyoxyethylene higher fatty acid esters such as polyoxyethylene monostearate; glycerin higher fatty acid esters such as oleic acid monoglyceride and stearic acid monoglyceride; polyoxyethylene polyoxypropylene block copolymer, polyoxyethylene distyrene phenyl ether Etc. can be exemplified.

Examples of non-reactive anionic emulsifiers include higher fatty acid salts such as sodium oleate; alkylaryl sulfonates such as sodium dodecylbenzene sulfonate; alkyl sulfates such as sodium lauryl sulfate; polyoxyethylene lauryl ether. Polyoxyethylene alkyl ether sulfate salts such as sodium sulfate; polyoxyethylene alkylaryl ether sulfate esters such as polyoxyethylene nonylphenyl ether sulfate; sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, polyoxyethylene lauryl sulfosuccinic acid Alkyl sulfosuccinate salts such as sodium and derivatives thereof; polyoxyethylene distyrene phenyl ether sulfate salts and the like can be exemplified.

The amount of the emulsifier used in the present invention is not necessarily limited, and can be appropriately selected according to the physical characteristics required when the crosslinked resin fine particles are used as the final binder. For example, the emulsifier is usually preferably 0.1 to 30 parts by mass, more preferably 0.3 to 20 parts by mass, based on 100 parts by mass of the total ethylenically unsaturated monomer. It is more preferably in the range of 5 to 10 parts by mass.

A water-soluble protective colloid can also be used in combination with the emulsion polymerization of the crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention. Examples of the water-soluble protective colloid include polyvinyl alcohols such as partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, and modified polyvinyl alcohol; cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose, and carboxymethyl cellulose salt; and natural polysaccharides such as guagam. Examples include saccharides, which can be used alone or in combination of multiple species. The amount of the water-soluble protective colloid used is 0.1 to 5 parts by mass, more preferably 0.5 to 2 parts by mass, based on 100 parts by mass of the total ethylenically unsaturated monomer.

<Aqueous medium used in emulsion polymerization>
Examples of the aqueous medium used for emulsion polymerization of crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention include water, and a hydrophilic organic solvent does not impair the object of the present invention. Can be used in.

<Polymerization initiator used in emulsion polymerization>
The polymerization initiator used to obtain the crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention is not particularly limited as long as it has the ability to initiate radical polymerization, and is known. An oil-soluble polymerization initiator or a water-soluble polymerization initiator can be used.

The oil-soluble polymerization initiator is not particularly limited, and for example, benzoyl peroxide, tert-butylperoxybenzoate, tert-butylhydroperoxide, tert-butylperoxy (2-ethylhexanoate), tert-butylper. Organic peroxides such as oxy-3,5,5-trimethylhexanoate, di-tert-butyl peroxide; 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4- Examples thereof include azobis compounds such as dimethylvaleronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 1,1'-azobis-cyclohexane-1-carbonitrile. These can be used alone or in admixture of two or more. It is preferable to use 0.1 to 10.0 parts by mass of these polymerization initiators with respect to 100 parts by mass of the ethylenically unsaturated monomer.

In the present invention, it is preferable to use a water-soluble polymerization initiator, for example, ammonium persulfate, potassium persulfate, hydrogen peroxide, 2,2'-azobis (2-methylpropion amidine) dihydrochloride, etc., which are conventionally known. Can be preferably used. Further, when carrying out emulsion polymerization, a reducing agent can be used in combination with the polymerization initiator, if desired. This makes it easy to accelerate the emulsion polymerization rate and to carry out the emulsion polymerization at a low temperature. Examples of such reducing agents include reducing organic compounds such as ascorbic acid, elsorbic acid, tartrate acid, citric acid, glucose, and metal salts such as formaldehyde sulfoxylate, sodium thiosulfite, sodium bisulfite, sodium bisulfite, and meta. Examples thereof include reducing inorganic compounds such as sodium bisulfite, ferrous chloride, longalite, and thiourea dioxide. It is preferable to use an amount of 0.05 to 5.0 parts by mass of these reducing agents with respect to 100 parts by mass of the total ethylenically unsaturated monomer.

<Conditions for emulsion polymerization>
In addition to the above-mentioned polymerization initiator, polymerization can also be carried out by a photochemical reaction, irradiation, or the like. The polymerization temperature is equal to or higher than the polymerization start temperature of each polymerization initiator. For example, in the case of a peroxide-based polymerization initiator, the temperature may usually be about 70 ° C. The polymerization time is not particularly limited, but is usually 2 to 24 hours.

<Other materials used in the reaction>
Further, if necessary, sodium acetate, sodium citrate, sodium bicarbonate, etc. as buffers, and octyl mercaptan, 2-ethylhexyl thioglycolate, octyl thioglycolate, stearyl mercaptan, lauryl mercaptan as chain transfer agents, etc. , T-dodecyl mercaptans and other mercaptans can be used in appropriate amounts.

When a monomer having an acidic functional group such as a carboxyl group-containing ethylenically unsaturated monomer is used for the polymerization of the crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention, before the polymerization It can be neutralized with a basic compound after polymerization. Upon neutralization, it can be neutralized with ammonia or alkylamines such as trimethylamine, triethylamine, butylamine; alcoholamines such as 2-dimethylaminoethanol, diethanolamine, triethanolamine, aminomethylpropanol; bases such as morpholine. .. However, highly volatile bases are highly effective in drying properties, and preferred bases are aminomethylpropanol and ammonia.

<Uncrosslinked compound (E) added to polymerized resin fine particles> Platinum-supported carbon The (meth) acrylic emulsion preferably used in the present invention is, in addition to the crosslinked resin fine particles, an uncrosslinked epoxy group. At least one uncrosslinked compound (E) selected from the group consisting of a containing compound, an uncrosslinked amide group-containing compound, an uncrosslinked hydroxyl group-containing compound, and an uncrosslinked oxazoline group-containing compound [hereinafter, compound (E) It may be described]. Compound (E) is a compound that disperses without being dissolved in an aqueous liquid medium.

The “uncrosslinked functional group-containing compound” as compound (E) is the inside of a (meth) acrylic emulsion preferably used in the present invention, such as the monomer contained in the monomer group (C1). Unlike a compound that forms a crosslinked structure (three-dimensional crosslinked structure), it refers to a compound that is added after emulsion polymerization (polymer formation) of resin fine particles (not involved in internal crosslink formation of resin fine particles). That is, "uncrosslinked" means that it is not involved in the formation of the internal crosslinked structure (three-dimensional crosslinked structure) of the (meth) acrylic emulsion preferably used in the present invention.

The (meth) acrylic emulsion preferably used in the present invention has a crosslinked structure to ensure electrolyte resistance, and by using the compound (E), the epoxy group in the compound (E), At least one functional group selected from amide groups, hydroxyl groups, and oxazoline groups can contribute to adhesion to the substrate or other electrode constituents. Furthermore, by adjusting the crosslinked structure and the amount of functional groups, it is possible to obtain a mixture ink having excellent durability of the microbial fuel cell.

The crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention need to be crosslinked inside the particles. Electrolyte resistance can be ensured by appropriately adjusting the cross-linking inside the particles. Further, at least one selected from the group consisting of a non-crosslinked epoxy group-containing compound, an uncrosslinked amide group-containing compound, an uncrosslinked hydroxyl group-containing compound, and an uncrosslinked oxazoline group-containing compound in functional group-containing crosslinked resin fine particles. By adding the uncrosslinked compound (E), an epoxy group, an amide group, a hydroxyl group or an oxazoline group can act on the base material to effectively improve the adhesion to the base material and other electrode constituent materials. it can. Since the functional group contained in the compound (E) is stable even when stored for a long period of time or when the electrode is manufactured, the effect of adhesion to the substrate is large even when used in a small amount. Furthermore, it is also excellent in storage stability. The compound (E) may react with a functional group in the crosslinked resin fine particles for the purpose of adjusting the flexibility and electrolytic solution resistance of the binder, but may react with the functional group in the crosslinked resin fine particles containing a functional group. If the functional groups in the compound (E) are used too much for the reaction, the functional groups that can interact with the base material or the electrode are reduced. Therefore, the reaction between the crosslinked resin fine particles in the (meth) acrylic emulsion preferably used in the present invention and the compound (E) does not impair the adhesion to the base material or other electrode constituent materials. There must be. When some of the functional groups contained in the compound (E) are used in the cross-linking reaction [when the compound (E) is a polyfunctional compound], the degree of cross-linking of these functional groups can be adjusted. A balance between electrolyte resistance and adhesion can be achieved.

<Uncrosslinked epoxy group-containing compound>
Examples of the uncrosslinked epoxy group-containing compound include epoxy group-containing ethylenically unsaturated monomers such as glycidyl (meth) acrylate and 3,4-epoxycyclohexyl (meth) acrylate; the epoxy group-containing ethylenically unsaturated monopoly. Radical polymerization resin obtained by polymerizing an ethylenically unsaturated monomer containing a metric; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol Diglycidyl ether, trimethylolpropan triglycidyl ether, diglycidyl aniline, N, N, N', N'-tetraglycidyl-m-xylylene diamine, 1,3-bis (N, N'-diglycidyl aminomethyl) Polyfunctional epoxy compounds such as cyclohexane; epoxy resins such as bisphenol A-epichlorohydrin type epoxy resin and bisphenol F-epichlorohydrin type epoxy resin can be mentioned.

Among the epoxy group-containing compounds, epoxy resins such as bisphenol A-epichlorohydrin type epoxy resin and bisphenol F-epichlorohydrin type epoxy resin, and ethylenia containing epoxy group-containing ethylenically unsaturated monomers A radical polymerization resin obtained by polymerizing a saturated monomer is preferable. Epoxy-based resins can be expected to have a synergistic effect of improving electrolyte resistance by having a bisphenol skeleton and improving substrate adhesion by the hydroxyl groups contained in the skeleton. Further, the radical polymerization resin obtained by polymerizing an ethylenically unsaturated monomer containing an epoxy group-containing ethylenically unsaturated monomer has more epoxy groups in the resin skeleton to improve substrate adhesion. In addition, since it is a resin, it can be expected to have an effect of improving the electrolytic solution resistance as compared with the monomer.

<Uncrosslinked amide group-containing compound>
Examples of the uncrosslinked amide group-containing compound include primary amide group-containing compounds such as (meth) acrylamide; N-methylol acrylamide, N, N-di (methylol) acrylamide, and N-methylol-N-methoxymethyl (meth). ) Alkyrol (meth) acrylamide compounds such as acrylamide; N-methoxymethyl- (meth) acrylamide, N-ethoxymethyl- (meth) acrylamide, N-propoxymethyl- (meth) acrylamide, N-butoxymethyl- (meth) ) Monoalkoxy (meth) acrylamide compounds such as acrylamide and N-pentoxymethyl- (meth) acrylamide; N, N-di (methoxymethyl) acrylamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N, N -Di (ethoxymethyl) acrylamide, N-ethoxymethyl-N-propoxymethylmethacrylamide, N, N-di (propoxymethyl) acrylamide, N-butoxymethyl-N- (propoxymethyl) metaacrylamide, N, N-di Dialkoxy such as (butoxymethyl) acrylamide, N-butoxymethyl-N- (methoxymethyl) metaacrylamide, N, N-di (pentoxymethyl) acrylamide, N-methoxymethyl-N- (pentoxymethyl) metaacrylamide. (Meta) acrylamide compounds; Dialkylamino (meth) acrylamide compounds such as N, N-dimethylaminopropylacrylamide and N, N-diethylaminopropylacrylamide; Dialkyls such as N, N-dimethylacrylamide and N, N-diethylacrylamide (Meta) acrylamide compound; Keto group-containing (meth) acrylamide compound such as diacetone (meth) acrylamide, etc. The above amide group-containing ethylenically unsaturated monomer; The amide group-containing ethylenically unsaturated monomer Examples thereof include a radical polymerization type resin obtained by polymerizing an ethylenic unsaturated monomer containing acrylamide.

Among the amide group-containing compounds, a radical polymerization resin obtained by polymerizing an ethylenically unsaturated monomer containing an amide group-containing ethylenically unsaturated monomer such as acrylamide is particularly preferable. By having more amide groups in the resin skeleton, the adhesion to the base material can be improved, and by using the resin, the effect of improving the electrolytic solution resistance as compared with the monomer can be expected.

<Uncrosslinked hydroxyl group-containing compound>
Examples of the uncrosslinked hydroxyl group-containing compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate 4-hydroxyvinylbenzene, and the like. Hydroxyl-containing ethylenically unsaturated monomer such as 1-ethynyl-1-cyclohexanol and allyl alcohol; radical polymerization obtained by polymerizing the ethylenically unsaturated monomer containing the hydroxyl group-containing ethylenically unsaturated monomer. Based resins: Linear aliphatic diols such as ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol; propylene glycol, neopentyl glycol , 3-Methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol and other branched chain aliphatic diols; 1,4-bis (hydroxymethyl) cyclohexane and other cyclic diols can give.

Among the hydroxyl group-containing compounds, a radical polymerization resin obtained by polymerizing an ethylenically unsaturated monomer containing a hydroxyl group-containing ethylenically unsaturated monomer, or cyclic diols is particularly preferable. The radical polymerization resin obtained by polymerizing an ethylenically unsaturated monomer containing a hydroxyl group-containing ethylenically unsaturated monomer improves the adhesion to the base material by having more hydroxyl groups in the resin skeleton. Further, since it is a resin, it can be expected to have an effect of improving electrolytic solution resistance as compared with a monomer. Further, the cyclic diols can be expected to have an effect of improving the electrolytic solution resistance by having a cyclic structure in the skeleton.

<Uncrosslinked oxazoline group-containing compound>
Examples of the uncrosslinked oxazoline group-containing compound include 2'-methylenebis (2-oxazoline), 2,2'-ethylenebis (2-oxazoline), and 2,2'-ethylenebis (4-methyl-2-oxazoline). ), 2,2'-propylene bis (2-oxazoline), 2,2'-tetramethylene bis (2-oxazoline), 2,2'-hexamethylene bis (2-oxazoline), 2,2'-octamethylene Bis (2-oxazoline), 2,2'-p-phenylenebis (2-oxazoline), 2,2'-p-phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-p -Phenylenebis (4-methyl-2-oxazoline), 2,2'-p-Phenylenbis (4-phenyl-2-oxazoline), 2,2'-m-Phenylenebis (2-oxazoline), 2,2 '-M-Phenylenebis (4-methyl-2-oxazoline), 2,2'-m-Phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-m-Phenylenebis (4- Phenylenebis-2-oxazoline), 2,2'-o-phenylenebis (2-oxazoline), 2,2'-o-phenylenebis (4-methyl-2-oxazoline), 2,2'-bis (2) -Oxazoline), 2,2'-bis (4-methyl-2-oxazoline), 2,2'-bis (4-ethyl-2-oxazoline), 2,2'-bis (4-phenyl-2-oxazoline) ), Further, an oxazoline group-containing radical polymerization resin and the like can be mentioned.

Among the oxazoline group-containing compounds, in particular, a phenylenebis-type oxazoline compound such as 2'-p-phenylenebis (2-oxazoline) or an ethylenically unsaturated monomer containing an oxazoline group-containing ethylenically unsaturated monomer. A radical polymerization resin obtained by polymerizing the above is preferable. The phenylene bis-type oxazoline compound has an effect of improving the electrolyte resistance by having a phenyl group in the skeleton. Further, the radical polymerization type resin obtained by polymerizing an ethylenically unsaturated monomer containing an oxazoline group-containing ethylenically unsaturated monomer has more oxazoline groups in the resin skeleton to improve substrate adhesion. By improving the resin, the electrolytic solution resistance can be improved as compared with the monomer.

(Addition amount and molecular weight of compound (E))
The compound (E) is preferably added in an amount of 0.1 to 50 parts by mass, more preferably 5 to 40 parts by mass, based on 100 parts by mass of the solid content of the crosslinked resin fine particles. Further, two or more kinds of the compound (E) can be used in combination.

The molecular weight of the compound (E) is not particularly limited, but the mass average molecular weight is preferably 1,000 to 1,000,000, more preferably 5,000 to 500,000. The mass average molecular weight is a polystyrene-equivalent value measured by a gel permeation chromatography (GPC) method.

<Conductive material>
Next, the conductive material will be described. The conductive material is contained to enhance the electron conductivity at the electrode and facilitate the redox reaction. Here, carbon materials are mainly mentioned, but the present invention is not limited to this.
The carbon material which is the conductive material used in the present invention is not particularly limited as long as it is a conductive carbon material, but carbon black, graphite, and conductive carbon fibers (carbon nanotubes, carbon nanofibers, carbon fibers). ), Graphene, fullerene, etc. can be used alone or in combination of two or more.

Carbon black includes furnace black, which is produced by continuously pyrolyzing a gas or liquid raw material in a reactor, especially acetylene black, which is made from ethylene heavy oil, and the raw material gas is burned to burn the flame to the bottom of the channel steel. Various types such as channel black that has been rapidly cooled and precipitated, thermal black that is obtained by periodically repeating combustion and thermal decomposition using gas as a raw material, and acetylene black that uses acetylene gas as a raw material, alone or 2 More than one type can be used together. In addition, normally oxidized carbon black, hollow carbon, and the like can also be used.

As the specific surface area of the carbon black used increases, the contact points between the carbon black particles increase, which is advantageous in reducing the internal resistance of the electrode. Specifically, the specific surface area (BET) obtained from the amount of nitrogen adsorbed is 20 m ² / g or more and 1500 m ² / g or less, preferably 50 m ² / g or more and 1500 m ² / g or less, and ^{more preferably 100 m 2} It is desirable to use the one of / g or more and 1500 m ^{2 / g or less.}

The particle size of the carbon black used is preferably 0.005 to 1 μm in terms of primary particle size, and particularly preferably 0.01 to 0.2 μm. However, the primary particle size referred to here is an average of the particle sizes measured by an electron microscope or the like.

It is desirable that the dispersed particle size of the carbon material, which is a conductive material, in the mixed ink is refined to 0.03 μm or more and 5 μm or less.

The dispersed particle size referred to here is a particle size (D50) that becomes 50% when the volume ratio of the particles is integrated from the finer particle size in the volume particle size distribution, and is generally used. It is measured with a particle size distribution meter, for example, a dynamic light scattering type particle size distribution meter (“Microtrack UPA” manufactured by Nikkiso Co., Ltd.).

Examples of commercially available carbon black include Talker Black # 4300, # 4400, # 4500, # 5500 (Tokai Carbon Co., Ltd., Furnace Black), Printex L etc. (Degussa Co., Ltd., Furnace Black), Raven7000, 5750, etc. 5250, 5000 ULTRA III, 5000 ULTRA, etc., Conductex SC ULTRA, etc.
, Conductex 975 ULTRA, etc., PUER BLACK 100, 115, 2
05 etc. (Made by Colombian, Furnace Black), # 2350, # 2400B, # 2600B, # 3050B, # 3030B, # 3230B, # 3350B, # 3400B, # 5400B etc. (Made by Mitsubishi Chemical Co., Ltd., Furness Black), MONARCH1400, 1300, 900, Vulcan XC-72R, BlackPearls2000, etc. (Cabot, Furness Black), Ensaco250G, Ensaco260G, Ensaco350G, SuperP-Li (TIMCAL), Ketjen Black EC-300J, EC-600JD (Axo) Examples of graphite such as Denka Black, Denka Black HS-100, FX-35 (manufactured by Denka, acetylene black) and the like include natural graphite such as artificial graphite, scaly graphite, lump graphite and earth graphite. The present invention is not limited to these, and two or more types may be used in combination.

As the conductive carbon fiber, those obtained by firing from a raw material derived from petroleum are preferable, but those obtained by firing from a raw material derived from a plant can also be used. For example, VGCF manufactured by Showa Denko KK, which is manufactured from petroleum-derived raw materials, can be mentioned.

<Oxygen reduction catalyst>
Next, the oxygen reduction catalyst will be described. Examples of the oxygen reduction catalyst include a noble metal catalyst, a base metal oxide catalyst, a carbon catalyst, and activated carbon. These may be used alone or in combination of two or more.

(Precious metal catalyst)
The noble metal catalyst is a catalyst containing at least one element selected from ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold among transition metal elements. These noble metal catalysts may be simple substances or supported on another element or compound. Among them, a catalyst-supported carbon material is a good example. The catalyst-supported carbon material refers to a material in which catalyst particles are supported on a carbon material as a catalyst carrier, and there are known or commercially available materials.

The loading ratio of the catalyst particles on the carbon material is not limited. When platinum is used as the catalyst particles, it can usually be supported up to about 1 to 70% by mass with respect to 100% by mass of the catalyst particles.

The carbon material as the catalyst carrier used in the present invention is not particularly limited as long as it is carbon particles derived from an inorganic material and / or carbon particles obtained by heat-treating an organic material.
Carbon particles derived from inorganic materials include carbon black (furness black, acetylene black, ketjen black, medium thermal carbon black), activated carbon, graphite, carbon nanotubes, carbon nanofibers, carbon nanohorns, graphene nanoplatelets, nanoporous carbon, etc. Examples include carbon fiber. Carbon materials have various physical properties and costs such as particle size, shape, BET specific surface area, pore volume, pore size, bulk density, DBP oil absorption, surface acid basicity, surface hydrophilicity, and conductivity, depending on the type and manufacturer. Since they are different, the optimum material is selected according to the intended use and required performance.
The organic material that becomes carbon particles by heat treatment is not particularly limited as long as it is a material that becomes carbon particles after heat treatment. Specific organic materials include phenol-based resin, polyimide-based resin, polyamide-based resin, polyamideimide-based resin, polyacrylonitrile-based resin, polyaniline-based resin, phenolformaldehyde resin-based resin, polyimidazole-based resin, polypyrrole-based resin, and poly. Examples thereof include benzoimidazole-based resins, melamine-based resins, pitches, brown charcoal, polycarbodiimide, biomass, proteins, fumic acid and the like, and derivatives thereof.
These carbon materials are used in one kind or two or more kinds.

Examples of commercially available catalyst-supported carbon materials include platinum-supported carbon particles such as TEC10E50E, TEC10E70TPM, TEC10V30E, TEC10V50E, and TEC66E50 manufactured by Tanaka Kikinzoku Kogyo Co., Ltd .;
Platinum-ruthenium alloy-supported carbon particles such as TEC66E50 and TEC62E58;
Can be purchased, but is not limited to these.

(Base metal oxide catalyst)
The base metal oxide catalyst used in the present invention is at least one selected from the group consisting of zirconium, tantalum, titanium, niobium, vanadium, iron, manganese, cobalt, nickel, copper, zinc, chromium, tungsten, and molybdenum. An oxide containing a transition metal can be used, and more preferably, a carbon nitride of these transition metal elements or a carbon dioxide oxide of these transition metal elements can be used.

Composition formula of the base metal oxide catalysts are, for example, M1C _p N _q O _r (although, M1 is a transition metal element, p, q, r represents the ratio of the number of atoms, 0 ≦ p ≦ 3,0 ≦ q ≦ 2, 0 <r ≦ 3), M2 _a M3 _b C _x N _y O _z (where M2 is zirconium, tantalum, titanium, niobium, vanadium, iron, manganese, cobalt, nickel, copper, It is one kind of metal selected from the group consisting of zinc, chromium, tungsten, and molybdenum, and M3 is at least one kind of metal different from M2 selected from the above group. A, b, x, y. , Z represents the ratio of the number of atoms, 0.5 ≦ a <1, 0 <b ≦ 0.5, 0 <x ≦ 3, 0 <y ≦ 2, 0 <z ≦ 3, and a + b = 1. .). Further, a catalyst in which these compounds and a conductive compound are combined can also be preferably used.

(Carbon catalyst)
The carbon catalyst is a carbon catalyst produced by mixing one or more kinds of carbon materials and a compound containing a nitrogen element and a base metal element and performing heat treatment, and conventionally known carbon catalysts can be used. The carbon material used for the carbon catalyst is not particularly limited as long as it is a carbon particle derived from an inorganic material and / or a carbon particle obtained by heat-treating an organic material. Generally, the active points of the carbon catalyst include a base metal element contained in a base metal-N4 structure (a structure in which four nitrogen elements are arranged on a plane centering on the base metal element) on the surface of the carbon particles, and the surface of the carbon particles. Examples include carbon elements in the vicinity of nitrogen elements introduced into the edge portion. Therefore, it is important for the carbon catalyst to contain the nitrogen element and the base metal element constituting the active site in order to have the oxygen reduction activity. Further, the carbon catalyst, BET specific surface area of preferably 20~2000m ² / g, more preferably 40~1000m ² / g, more preferably 60~600m ² / g.

Examples of carbon particles derived from inorganic materials include carbon blacks such as furnace black, acetylene black, ketjen black and medium thermal carbon black: activated carbon, graphite, carbon nanotubes, carbon nanofibers, carbon nanohorns, graphene and graphene nanoplatelets. , Nanoporous carbon, carbon fiber and the like. Carbon particles have various physical properties such as particle size, shape, BET specific surface area, pore volume, pore size, bulk density, DBP oil absorption, surface acid basicity, surface hydrophilicity, and conductivity, depending on the type and manufacturer. Since the costs are different, the optimum material can be selected according to the intended use and required performance. Inorganic carbon particles are used in one type or two or more types.

As the carbon particles derived from the inorganic material, graphene nanoplatelets, carbon black, carbon nanotubes and the like are preferable because it is easy to obtain a carbon catalyst having a large specific surface area and high electron conductivity.

The organic material that becomes carbon particles by heat treatment is not particularly limited as long as it is a material that becomes carbon particles after heat treatment. In order to allow the carbon particles after the heat treatment to contain a hetero element as an active site, it may be preferable to use an organic material containing the same hetero element in advance. Specific organic materials include phenol-based resin, polyimide-based resin, polyamide-based resin, polyamideimide-based resin, polyacrylonitrile-based resin, polyaniline-based resin, phenolformaldehyde resin-based resin, polyimidazole-based resin, polypyrrole-based resin, and poly. Examples thereof include benzoimidazole-based resins, melamine-based resins, pitches, brown charcoal, polycarbodiimide, biomass, proteins, fumic acid and the like, and derivatives thereof.

The compound containing a nitrogen element and a base metal element may be a compound containing one or more kinds of nitrogen element and a base metal element, and is not particularly limited as long as it does not deviate from the gist of the present invention. For example, organic compounds such as dyes and polymers containing metals, and inorganic compounds such as elemental metals, base metal oxides, and metal salts can be mentioned. The compound may be used alone or in combination of two or more. The base metal element is a metal element excluding noble metal elements (lutenium, rhodium, palladium, silver, osmium, iridium, platinum, gold) among the transition metal elements, and the base metal elements include cobalt, iron, nickel, manganese, and copper. , Titanium, vanadium, chromium, zinc, tin, aluminum, zirconium, niobium, tantalum, and magnesium.
From the viewpoint of efficiently introducing a nitrogen element or a base metal element into a carbon catalyst, a nitrogen-containing aromatic compound capable of containing the base metal element in the molecule is preferable. Specific examples thereof include phthalocyanine compounds, naphthalocyanine compounds, porphyrin compounds, tetraazaannulene compounds and the like. The aromatic compound may be one into which an electron-withdrawing functional group or an electron-donating functional group has been introduced. In particular, the phthalocyanine compound is particularly preferable as a raw material because compounds containing various base metal elements are available and the cost is low. Specific examples thereof include metal phthalocyanine compounds such as cobalt phthalocyanine compounds, nickel phthalocyanine compounds and iron phthalocyanine compounds. By using these raw materials, it is possible to provide a carbon catalyst that is inexpensive and has high oxygen reduction activity.

The method for producing the carbon catalyst is not particularly limited, and a method of supporting a cyclic organic compound on the surface of a carbon carrier and carbonizing it, a method of carbonizing a mixture of the cyclic organic compound and other organic materials, and a method of carbonizing an organic material containing no cyclic organic compound. Conventionally known methods such as a method of carbonizing and a method of using carbon particles derived from an inorganic carbon material can be used. A preferred production method is a method in which carbon particles derived from an inorganic carbon material and a compound containing a nitrogen element and a base metal element are mixed and then heat-treated in an inert gas atmosphere to obtain a carbon catalyst. The heat treatment may be performed in multiple steps at a plurality of temperatures, and may include a step of washing with an acid and drying after or during the heat treatment step.

(Activated carbon)
Specific examples of the activated carbon include activated carbons activated by phenol-based, coconut husk-based, rayon-based, acrylic-based, coal-petroleum-based pitch coke, mesocarbon microbeads (MCMB) and the like. Those having a large specific surface area, which can form an interface having a wider area even with the same mass, are preferable. Specifically, the specific surface area is ^{preferably 30 m 2} / g or more, more preferably 500 to 5000 m ² / g, and further preferably 1000 to 3000 m ² / g.

<Aqueous liquid medium>
Water is preferably used as the aqueous liquid medium used in the present invention, but if necessary, for example, a liquid medium compatible with water is used in order to improve the coatability on the conductive substrate. You may.
Liquid media compatible with water include alcohols, glycols, cellosolves, aminoalcohols, amines, ketones, carboxylic acid amides, phosphate amides, sulfoxides, carboxylic acid esters, and phosphate esters. , Ethers, nitriles and the like, and may be used as long as they are compatible with water.

Further, a thickener, a dispersant, a film forming aid, a defoaming agent, a leveling agent, a preservative, a pH adjuster and the like can be added to the mixture ink as needed. In particular, since it may be difficult to obtain the viscosity and dispersion stability of the mixture ink only with the water-based resin fine particles, it is preferable to contain a thickener or a dispersant.

The thickener and dispersant are preferably water-soluble resins, and are not particularly limited, but for example, acrylic resins, polyurethane resins, polyester resins, polyamide resins, polyimide resins, polyallylamine resins, phenol resins, etc. Examples thereof include polymer compounds containing polysaccharide resins such as epoxy resin, phenoxy resin, urea resin, melamine resin, alkyd resin, formaldehyde resin, silicon resin, fluorine resin and carboxymethyl cellulose. Further, as long as it is water-soluble, a modified product, a mixture, or a copolymer of these resins may be used. These may be used alone or in combination of two or more.

<How to adjust the mixture ink for microbial fuel cells>
There are no particular restrictions on the method of preparing the mixture ink. In the preparation, each component may be dispersed at the same time, or the conductive material and / or the oxygen reduction catalyst may be dispersed in the aqueous liquid medium, and then the aqueous resin fine particles may be added, and the conductive material and / or oxygen reduction to be used may be added. It can be optimized with a catalyst, aqueous resin particles, and aqueous liquid medium. However, if the aqueous catalyst paste composition is prepared first and the aqueous resin fine particles are added afterwards to prepare the mixed material ink, it is possible to greatly contribute to cost reduction such as shortening the dispersion time.

For example, the conductive material and / or the oxygen reduction catalyst is 5 to 80 parts by mass, preferably 10 to 60 parts by mass, and the aqueous resin fine particles are 0.01 to 80 parts by mass with respect to 100 parts by mass of the solid content of the mixture ink of the present invention. It is by mass, preferably 0.02 to 60 parts by mass.

<Disperser / Mixer>
As an apparatus used for obtaining a mixture ink for a microbial fuel cell, a disperser or a mixer usually used for pigment dispersion or the like can be used.

For example, mixers such as disper, homomixer, or planetary mixer; homogenizers such as "Clearmix" manufactured by M-Technique or "Philmix" manufactured by PRIMIX; paint conditioner (manufactured by Red Devil), ball mill, sand mill. (Symmal Enterprises "Dyno Mill", etc.), Atwriter, Pearl Mill (Eirich "DCP Mill", etc.), or media type disperser such as Coball Mill; Wet Jet Mill (Genus "Genus PY", Sugino) Medialess dispersers such as Machine's "Starburst", Nanomizer's "Nanomizer"), M-Technique's "Claire SS-5", or Nara Machinery's "MICROS"; or other roll mills, etc. However, it is not limited to these. Further, as the disperser, it is preferable to use one that has been subjected to metal contamination prevention treatment from the disperser.

For example, when using a media type disperser, a method in which the agitator and vessel use a disperser made of ceramic or resin, or a disperser in which the surface of the metal agitator and vessel is treated with tungsten carbide spraying or resin coating. Is preferably used. As the medium, it is preferable to use glass beads, zirconia beads, or ceramic beads such as alumina beads. Also, when a roll mill is used, it is preferable to use a ceramic roll. As the disperser, only one type may be used, or a plurality of types of devices may be used in combination. Further, when the catalyst-supported carbon material is easily cracked or crushed by a strong impact, a medialess disperser such as a roll mill or a homogenizer is preferable to a media type disperser.

<Conductive substrate>
The conductive base material used in the electrode of the present invention is preferably one having excellent corrosion resistance and electrical conductivity, a large surface area, and excellent diffusion of reactants and products, and the material and shape are not particularly limited. For example, in addition to carbon materials such as graphite paper, graphite cloth and graphite felt, metal materials such as stainless mesh and platinum mesh can be used, but the present invention is not limited to this. The conductive base material used for the electrode may be water-repellent in advance. For example, the cathode is impregnated with a dispersion of PTFE, dried, and then heated at around 400 ° C. to develop water repellency. Further, the conductive material may be dispersed in the PTFE dispersion liquid. The water repellent treatment is not limited to these.

<Electrode coating method>
The method for applying the mixture ink of the present invention is not particularly limited, and a known method can be used. Examples include a gravure coating method, a spray coating method, a screen printing method, a dip coating method, a die coating method, a roll coating method, a doctor coating method, a knife coating method, a screen printing method or an electrostatic coating method. As the drying method, a stand-alone drying, a blower dryer, a warm air dryer, an infrared heater, a far infrared heater and the like can be used, but the drying method is not particularly limited thereto.

<Construction of electrodes for microbial fuel cells>
The configuration of the electrode used in the present invention is not particularly limited. For example, the conductive base material is subjected to a water-repellent treatment as described above, and then the mixture ink of the present invention is applied to one side to form a catalyst layer.

<Composition of microbial fuel cell>
As described above, the microbial fuel cell consists of a conductive support as an anode in which electron donating microorganisms are held and a conductive support as a cathode coated with a catalyst material for a fuel cell as an electrolytic solution in organic waste water. In a one-tank configuration in which a partition is not provided in an electrolytic cell containing the above, or in a two-tank configuration in which a solid polymer membrane is used to separate an anode tank and a cathode tank, such as a polymer electrolyte fuel cell. Good. Further, not only the electrolytic cell surrounded by a surface but also an unenclosed environment such as a paddy field, a lake, a river, or the sea may be used. For example, a cathode is installed on the liquid surface, side surface, and bottom surface that separates the inside of the electrolytic cell that holds the electrolytic solution from the outside of the electrolytic cell such as the atmosphere containing oxygen, or a cassette type electrode that can take in outside air is placed in the liquid. A form such as immersing in is conceivable. At this time, the catalyst layer of the cathode is in contact with the electrolytic solution, and the back surface thereof is installed so as to be in contact with the atmosphere containing oxygen. As a result, the atmosphere containing oxygen directly flows into the cathode from the outside of the electrolytic cell, and a reaction occurs on the catalyst in the cathode in contact with the electrolytic solution.

The electrolytic solution used in a microbial fuel cell has proton conductivity and contains a substrate that is oxidatively decomposed by microorganisms. The substrate is not particularly limited as long as it is a substance that can be metabolized by the microorganism that donates electrons. For example, in addition to organic substances such as sugars, proteins and lipids, inorganic substances such as ammonia may be mentioned, and one or more of them may be contained. Therefore, as the electrolytic solution, domestic wastewater, industrial wastewater, etc. that satisfy the above conditions can be used. Further, a mediator responsible for electron transfer between the microorganism and the anode may be introduced, and examples thereof include methylene blue and neutral red.

The microorganism that donates electrons in the microbial fuel cell may be a single type or a plurality of types as long as it causes an anodic reaction that oxidatively decomposes the substrate to generate electrons. In addition, microorganisms are retained in the electrolytic cell by floating in the electrolytic cell or immobilizing on the anode. The microbial species are not particularly limited, and those belonging to the genus Shewanella and the genus Geobacter can be exemplified.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples do not limit the scope of rights of the present invention. In addition, "part" in an Example and a comparative example represents a "mass part".

<Preparation of aqueous resin fine particle dispersion>
[Synthesis Example 1]
In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a recirculator, 40 parts of ion-exchanged water and 0.2 part of ADEKA CORPORATION SR-10 (manufactured by ADEKA Corporation) as a surfactant are charged separately. 48.5 parts of methyl methacrylate, 50 parts of butyl acrylate, 1 part of acrylic acid, 0.5 part of 3-methacryloxypropyltrimethoxysilane, 53 parts of ion-exchanged water, and ADEKA CORPORATION SR-10 as a surfactant (ADEKA Corporation) (Manufactured) 1.8 parts of the pre-emulsion mixed in advance was further added. After raising the internal temperature to 70 ° C. and sufficiently substituting with nitrogen, 10% of 10 parts of a 5% aqueous solution of potassium persulfate was added to initiate polymerization. After keeping the inside of the reaction system at 70 ° C. for 5 minutes, the rest of the pre-emulsion and the rest of the 5% aqueous solution of potassium persulfate were added dropwise over 3 hours while keeping the internal temperature at 70 ° C., and stirring was continued for another 2 hours. .. After confirming that the conversion rate exceeded 98% by solid content measurement, the temperature was cooled to 30 ° C. 25% aqueous ammonia was added to adjust the pH to 8.5, and the solid content was adjusted to 40% with ion-exchanged water to obtain an aqueous resin fine particle dispersion. The solid content was determined from the baking residue at 150 ° C. for 20 minutes.

<Production of compound (E) [Production of epoxy group-containing compound]>
[Manufacturing Example 1]
20 parts of isopropyl alcohol and 20 parts of water were charged in a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a recirculator, and 40 parts of methyl methacrylate, 40 parts of methyl acrylate, and 20 parts of glycidyl methacrylate were separately added to the dropping tank 1. Further, 2 parts of potassium persulfate was dissolved in 30 parts of isopropyl alcohol and 30 parts of water and charged into the dropping tank 2. After raising the internal temperature to 80 ° C. and sufficiently replacing the nitrogen with nitrogen, the dropping tanks 1 and 2 were dropped over 2 hours to carry out polymerization. After completion of the dropping, stirring was continued for 1 hour while maintaining the internal temperature at 80 ° C., and after confirming that the conversion rate exceeded 98% by solid content measurement, the temperature was cooled to 30 ° C., and the epoxy having a solid content of 40%. A group-containing compound (methyl methacrylate / methyl acrylate / glycidyl methacrylate copolymer) solution was obtained. The solid content was determined from the baking residue at 150 ° C. for 20 minutes.

<Production of compound (E) [Production of amide group-containing compound]>
[Manufacturing Example 2]
90 parts of water is charged in a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a refluxer, and 20 parts of acrylamide is separately dissolved in the dropping tank 1 and 2 parts of potassium persulfate is dissolved in 90 parts of water. It was charged in the dropping tank 2. After raising the internal temperature to 80 ° C. and sufficiently replacing the nitrogen with nitrogen, the dropping tanks 1 and 2 were dropped over 2 hours to carry out polymerization. After completion of the dropping, stirring was continued for 1 hour while maintaining the internal temperature at 80 ° C., and after confirming that the conversion rate exceeded 98% by solid content measurement, the temperature was cooled to 30 ° C. and amide having a solid content of 40%. A group-containing compound (polyacrylamide) solution was obtained. The solid content was determined from the baking residue at 150 ° C. for 20 minutes.

[Manufacturing Example 3]
40 parts of water was charged in a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a refluxer, and 40 parts of 2-ethylhexyl acrylate, 40 parts of styrene, and 20 parts of dimethylacrylamide were separately added to the dropping tank 1 and excess. Two parts of potassium sulfate were dissolved in 60 parts of water and charged into the dropping tank 2. After raising the internal temperature to 80 ° C. and sufficiently replacing the nitrogen with nitrogen, the dropping tanks 1 and 2 were dropped over 2 hours to carry out polymerization. After completion of the dropping, stirring was continued for 1 hour while maintaining the internal temperature at 80 ° C., and after confirming that the conversion rate exceeded 98% by solid content measurement, the temperature was cooled to 30 ° C. and amide having a solid content of 40%. A group-containing compound (2-ethylhexyl acrylate / styrene / dimethylacrylamide copolymer) solution was obtained. The solid content was determined from the baking residue at 150 ° C. for 20 minutes.

<Production of compound (E) [Production of hydroxyl group-containing compound]>
[Manufacturing Example 4]
20 parts of isopropyl alcohol and 20 parts of water are charged in a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a recirculator, and 40 parts of methyl methacrylate, 40 parts of butyl acrylate, and 20 parts of 2-hydroxyethyl methacrylate are separately added dropwise. In the tank 1, 2 parts of potassium persulfate was dissolved in 30 parts of isopropyl alcohol and 30 parts of water and charged into the dropping tank 2. After raising the internal temperature to 80 ° C. and sufficiently replacing the nitrogen with nitrogen, the dropping tanks 1 and 2 were dropped over 2 hours to polymerize. After completion of the dropping, stirring was continued for 1 hour while maintaining the internal temperature at 80 ° C., and after confirming that the conversion rate exceeded 98% by solid content measurement, the temperature was cooled to 30 ° C. and a hydroxyl group having a solid content of 40%. A solution of the containing compound (methyl methacrylate / butyl acrylate / 2-hydroxyethyl methacrylate copolymer) was obtained. The solid content was determined from the baking residue at 150 ° C. for 20 minutes.

[Synthesis Examples 2 to 16]
The compounding compositions shown in Tables 1, 2 and 3 were synthesized in the same manner as in Synthesis Example 1 to obtain aqueous resin fine particle dispersions of Synthesis Examples 2 to 16. However, in Synthesis Examples 15 and 16, the resin aggregated during emulsion polymerization, and the desired resin fine particles could not be obtained.

<Base metal oxide catalyst>
[Manufacturing Example 5]
Oxyzirconium phthalocyanine (manufactured by Dainichiseika Co., Ltd.) is heat-treated in an electric furnace at 1000 ° C. for 10 hours under a mixed gas atmosphere of _{H 2} / O _{2 / Ar (volume ratio 0.02 / 0.005 / 0.975).} The obtained powder was pulverized in a dairy pot to obtain a base metal oxide-based catalyst.

<Carbon catalyst>
[Manufacturing Example 6]
Ketjen black (manufactured by Lion) and iron phthalocyanine (manufactured by Sanyo Dye) are weighed at a mass ratio of 1 / 0.5 and dry-mixed with a particle compounding device Mechanofusion (manufactured by Hosokawa Micron) to obtain a mixture. It was. The above mixture was filled in an alumina crucible and heat-treated in an electric furnace at 800 ° C. for 2 hours in a nitrogen atmosphere to obtain a carbon catalyst.

<Adjustment of composition for forming microbial fuel cell electrode>
[Example 1]
4.8 parts of TEC10E50E (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) as a platinum-supported carbon material, 30.2 parts of water as an aqueous liquid medium, and 60 parts of a carboxymethyl cellulose aqueous solution (solid content 2%) as a thickener are put into a mixer and mixed. Then, it was further put into a sand mill and dispersed. Then, 5 parts (solid content 40%) of the aqueous resin fine particle dispersion described in Synthesis Example 1 was added and mixed with a disper to obtain a mixed material ink.

[Examples 2-49, Comparative Examples 1-12]
Using the conductive materials, oxygen reduction catalysts, aqueous resin fine particles, and aqueous liquid medium shown in Tables 4, 5, 6 and 7, mixed material inks were prepared in the same manner as in Example 1 and compared with Examples 2 to 49. The mixture inks of Examples 1 to 12 were obtained.

<Creation of electrodes for microbial fuel cells>
In the water-repellent treatment of the conductive substrate used for the electrode, the carbon cloth was immersed in a PTFE solution, dried, and then heat-treated at 380 ° C. The mixture ink of Example 1 was applied to one side of the carbon cloth so that the catalyst amount was 0.5 mg / cm ^2, and then heated and dried at 110 ° C. for 30 minutes to prepare an electrode for a microbial fuel cell.

Using the mixture inks of Examples 2 to 49 and Comparative Examples 1 to 12 shown in Tables 4, 5, 6 and 7, the electrodes for the microbial fuel cell were prepared in the same manner as the electrodes for the microbial fuel cell, respectively. ..

(Adhesion of electrodes)
Each of the electrodes prepared above was cut with a knife from the surface of the electrode to the depth reaching the base material, and six grid cuts were made in each of the vertical and horizontal directions at 2 mm intervals. Adhesive tape was attached to this notch and immediately peeled off, and the degree of catalyst dropout was visually determined. The evaluation criteria are shown below. The results are shown in Tables 4-7.
◯: "No peeling (level without practical problem)"
○ △: "Slight peeling (problem but usable level)"
Δ: "Half peeling"
×: "Peeling in most parts"

From the results shown in Tables 4, 5, 6 and 7, the mixture ink containing the aqueous resin fine particles and the conductive material and / or the oxygen reduction catalyst was compared with the case where the dissolved resin was used when the electrode was prepared. Adhesion has improved.

<Microbial fuel cell>
The evaluation by the microbial fuel cell of the present invention was carried out in a one-tank configuration.

^{After anaerobically culturing a mixed solution of Shewanella monoidenis MR-1 (single culture, 15} cells / mL) and paddy soil at 30 ° C. for 3 days as an electron donating microorganism in an electrolytic tank having a capacity of 30 mL. _{A buffer solution of K 2} HPO ₄ / KH ₂ PO ₄ (pH 7.0) is used as the electrolyte solution, and 2.0 g COD / L / day (COD: chemical oxygen demand) of domestic wastewater containing sodium acetate as a nutritional substrate. Was continuously infused. Carbon felt was inserted into the electrolytic cell as the conductive support of the anode, and the electrodes of Examples 1 to 49 and Comparative Examples 1 to 12 were installed on the side surfaces of the electrolytic cell as the cathode, respectively.

(Power generation test of microbial fuel cell)
Current-voltage measurements were performed and evaluated at room temperature using a potentio galvanostat (VersaSTAT3, manufactured by Princeton Applied Research). As the power generation characteristics, the power generation characteristics of Examples 1 to 10, 41, 42 and Comparative Examples 2 and 3 are the percentage (%) of the power generation amount per unit area of each electrode with respect to the power generation amount per electrode unit area of Comparative Example 1. I asked. Similarly, Examples 11-20, 43, 44 and Comparative Examples 5 and 6 are Comparative Example 4, Examples 21-30, 45, 46, 47 and Comparative Examples 8 and 9 are Comparative Example 7 and Examples 31-40. , 48, 49 and Comparative Examples 11 and 12 determined the percentage (%) of the power generation amount per unit area of each electrode with respect to the power generation amount per unit area of the electrode of Comparative Example 10.

From the results shown in Tables 4, 5, 6 and 7, it can be seen that the amount of power generation is increased by the combination of the aqueous resin fine particles and the oxygen reduction catalyst. It is considered that this is because the aqueous resin fine particles are point-bonded to the catalyst, so that the reaction interface is increased as compared with Comparative Example 1 and the power generation characteristics are improved. Furthermore, even if the amount of the aqueous resin fine particles was reduced, the power generation characteristics were improved while maintaining the adhesiveness. This is because the water-based resin fine particles have high adhesion, so there is no problem in adhesion even if the content is reduced, and it is considered that the power generation characteristics are improved by the amount of the resin that becomes resistance.

Claims (8)

A composition for forming a microbial fuel cell electrode containing a conductive material and / or an oxygen reduction catalyst and aqueous resin fine particles having an average particle size of 10 to 500 nm. The composition for forming a microbial fuel cell electrode according to claim 1, wherein the aqueous resin fine particles contain an acrylic emulsion polymer.
The composition for forming a microbial fuel cell electrode according to claim 1 or 2, wherein the conductive material is a carbon material.
The composition for forming a microbial fuel cell electrode according to any one of claims 1 to 3, wherein the oxygen reduction catalyst is one or more selected from the group consisting of a noble metal catalyst, a base metal oxide catalyst, a carbon catalyst and activated carbon.
The composition for forming a microbial fuel cell electrode according to any one of claims 1 to 4, further comprising an aqueous liquid medium.
An electrode for a microbial fuel cell, which comprises using the composition for forming a microbial fuel cell electrode according to any one of claims 1 to 5.
The electrode for a microbial fuel cell according to claim 6, which is installed on any of the liquid surface, the liquid surface, the side surface, and the bottom surface of the microbial fuel cell, one surface of which is in contact with air outside the tank and the back surface of which is in contact with an electrolytic solution.
A microbial fuel cell according to claim 6 or 7, wherein the microbial fuel cell electrode is used.