JP5359074B2 - Aqueous carbon material composition and battery composition using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous system carbon material composition extremely excellent in water resistance, alkali-proof capability, and chemical resistance and also excellent in preservation stability and rigidity of a coated film after coating process in order to realize a high conductive carbon material with an aqueous dispersion at high level, and provide a composition for a battery electrode excellent in high conductivity especially for a secondary battery and excellent in bonding property with a collector and in charge/discharge cycle characteristics even under a high temperature environment due to generated heat while in charge/discharge or the like, by realizing a high conductivity and high base material adhesion in application in a fuel cell, a solar cell and capacitor. <P>SOLUTION: The aqueous carbon material composition contains a carbon material treated by anion resin and/or nonionic resin, an aqueous resin and an aqueous medium. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a water-based carbon material composition and a battery electrode composition excellent in high conductivity, storage stability, high coating property and environmental safety as a carbon material composition dispersed in water.

  In recent years, various efforts have been made around the world to realize a low-carbon society, but research and development aimed at reducing carbon dioxide using fuel cells, solar cells, secondary batteries, capacitors, etc. have been made. Yes.

  Further, due to the advancement of electronic technology, the performance of electronic devices has been improved and miniaturization and portability have progressed, and a secondary battery with high energy density is desired as its power source. Electronic devices are becoming smaller and lighter, and there is a strong demand for smaller and lighter batteries for power supplies. There is a growing demand for secondary batteries that can be used repeatedly instead of primary batteries. Various secondary batteries have been developed to meet these requirements. For example, nickel cadmium batteries, nickel hydride secondary batteries, lithium ion secondary batteries, and the like have been put into practical use.

  As electrodes constituting the constituent members of these secondary batteries, an active material such as a hydrogen storage alloy or graphite, carboxymethylcellulose as a thickener, styrene / butadiene latex as a binder, and water as a dispersion medium. A method is disclosed in which a paste obtained by kneading is applied on the surface of a current collector and dried to produce (Patent Document 1, Patent Document 2).

  In addition to the above, binders used for electrodes include acrylic resins, fluorine-containing resins such as polytetrafluoroethylene, ethylene / propylene / diene copolymer rubber, styrene / ethylene / butene / styrene block copolymer. A water-insoluble resin such as a combined rubber is used, and a mixture with a water-soluble resin such as polyvinyl alcohol, polyacrylic acid salt, water-soluble cellulose derivative, polyethylene oxide, and polyvinylpyrrolidone is used as necessary. (Patent Documents 3 to 7).

  However, it cannot be said that these binders have sufficient adhesion to the current collector. In a secondary battery using an electrode in which the adhesion between the electrode layer and the current collector is not sufficient, there is a problem that the battery characteristics such as the charge / discharge cycle characteristics cannot be improved. As described above, the binder is required to be a resin having a high binding force between the current collector, the electrode active material, and the conductive materials and between the materials.

  Furthermore, various resins have been disclosed in order to solve the decrease in charge / discharge cycle life and battery capacity. For example, an ethylene / vinyl acetate / long chain vinyl ester copolymer (Patent Document 8) and a copolymer of acrylic acid or acrylate and vinyl alcohol (Patent Document 9) are disclosed.

  However, in such a binder, the adhesion of the electrode active material to the current collector is insufficient, and as the charge / discharge cycle progresses, the active material gradually falls off the current collector, and the battery performance deteriorates. There was a problem of going. In particular, there has been a problem that the capacity rapidly decreases when repeatedly exposed to a high temperature environment for a long time due to heat generation during charging and discharging.

  Furthermore, in order to improve the adhesion of the electrode and the current collector to improve the characteristics of the secondary battery, the conductive bond for the electrode containing a carboxy-modified styrene butadiene copolymer latex having a gel content defined within a predetermined range. A wearing composition is disclosed (Patent Document 10). Further, it is disclosed that an aqueous dispersion composition containing polytetrafluoroethylene and polyoxyethylene alkyl ether is suitable as a binder for batteries (Patent Document 11).

However, even with the binders disclosed in Patent Documents 10 and 11, the effect of improving the adhesion between the electrode and the current collector is not necessarily sufficient. As described above, there is a problem in that the capacity of the secondary battery having an electrode having insufficient adhesion is rapidly reduced when it is repeatedly exposed to a high temperature environment for a long time due to heat generation during charging and discharging.
JP-A-11-67213 JP 2002-237305 A JP-A-4-272656 Japanese Patent Laid-Open No. 10-40916 Japanese Patent Laid-Open No. 2001-283553 Japanese Patent Laid-Open No. 9-63589 Japanese Patent Laid-Open No. 6-13080 JP-A-9-161803 JP 7-226205 A JP-A-9-320604 JP-A-8-269285

  The present invention was made in the background of the above-mentioned problems of the prior art, and enables water-based dispersion of a highly conductive carbon material at a high level. Therefore, the water resistance, alkali resistance, and chemical resistance are extremely excellent. An object of the present invention is to provide an aqueous carbon material composition having excellent storage stability and coating film toughness after coating. Furthermore, it achieves high conductivity and high substrate adhesion in applications such as fuel cells, solar cells, capacitors, etc. Especially in secondary batteries, it has excellent conductivity and adhesion to current collectors, and it generates heat during charging and discharging. An object of the present invention is to provide a battery electrode composition having excellent charge / discharge cycle characteristics even under repeated and high temperature environments.

The present invention includes a carbon material treated with an anionic resin and / or a nonionic resin, an aqueous resin, and an aqueous medium, and the aqueous resin is an epoxy group with respect to all ethylenically unsaturated monomers. One or more monomers selected from the group consisting of an ethylenically unsaturated monomer having an ethylenic unsaturated monomer having an alkoxysilyl group, and an ethylenically unsaturated monomer having an N-methylol group One or more monomers selected from the group consisting of 0.1 to 5.0% by mass , an ethylenically unsaturated monomer having a carboxyl group, and an ethylenically unsaturated monomer having a tertiary butyl group and 0.2 to 5.0 wt%, comprising other one or more ethylenically unsaturated monomers from 90.0 to 99.7 wt% of an ethylenically unsaturated monomer containing emulsion polymerization aqueous resin der Ru water based carbon material composition On.

The present invention also includes a carbon material treated with an anionic resin and / or a nonionic resin, an aqueous resin, and an aqueous medium, and the aqueous resin is based on the total ethylenically unsaturated monomer. 0.5 to 10.0% by mass of one or more monomers selected from the group consisting of an ethylenically unsaturated monomer having a carboxyl group and an ethylenically unsaturated monomer having a tertiary butyl group; An aqueous resin formed by emulsion polymerization of an ethylenically unsaturated monomer containing 90.0 to 99.5% by mass of one or more other ethylenically unsaturated monomers, ing and a compound having a reactive and functional group capable on water-based carbon material composition.

The present invention also includes a carbon material treated with an anionic resin and / or a nonionic resin, an aqueous resin, and an aqueous medium, and the aqueous resin is based on the total ethylenically unsaturated monomer. Ethylenic containing 0.5 to 10.0% by mass of ethylenically unsaturated monomer having a carbonyl group and 90.0 to 99.5% by mass of one or more other ethylenically unsaturated monomers a water-based resin obtained by the emulsion polymerization of unsaturated monomer, further, relates to water-based carbon material composition ing and a compound having a functional group capable of reacting with a carbonyl group.

Moreover, this invention relates to the said water-based carbon material composition whose anionic resin and / or nonionic resin are 0.01-50 mass% with respect to a carbon material.
The present invention also relates to the aqueous carbon material composition, wherein the other one or more types of ethylenically unsaturated monomers include one or more selected from the group consisting of styrene, 2-ethylhexyl acrylate, and cyclohexyl methacrylate.

Furthermore, the present invention relates to a battery electrode composition using the aqueous carbon material composition.

  The aqueous carbon material composition of the present invention is excellent in the stability of the coating liquid, the adhesion to the current collector, and the flexibility. The fuel cell, solar cell, capacitor, and secondary battery using the battery electrode composition of the present invention achieve high conductivity. Especially in the secondary battery, it is repeatedly or under a high temperature environment due to heat generation during charging and discharging. Even if it exists, it becomes possible to reduce the discharge capacity fall in a charging / discharging cycle, and the long-life secondary battery excellent in the discharge rate characteristic and cycling characteristics can be provided.

  Each component of the aqueous carbon material composition of the present invention will be described.

  In addition, when expressed as “(meth) acrylic acid”, “(meth) acrylate”, and “(meth) acryloyloxy”, “acrylic acid and / or methacrylic acid”, “acrylate and / or methacrylate”, respectively. And “acryloyloxy and / or methacryloyloxy”.

<Anionic resin and / or nonionic resin>
The anionic resin and / or nonionic resin of the present invention is not particularly limited as long as the carbon material can be stably dispersed in the aqueous medium without any problem in compatibility with the aqueous resin.

  As an anionic resin, what neutralized the resin which has acidic functional groups, such as a carboxyl group, a phosphoric acid group, or a sulfonic acid group, with the basic compound is mentioned. Specifically, poly (meth) acrylic acid, acrylic acid / styrene copolymer, other (meth) acrylic acid copolymers, maleic anhydride / styrene copolymers, maleic anhydride / diisobutylene copolymers, Maleic anhydride / α-olefin copolymers, other maleic anhydride copolymers, (meth) acrylate monomer copolymers having phosphoric acid groups, (meth) acrylate monomer copolymers having sulfonic acid groups, naphthalene sulfone Examples include those obtained by neutralizing resins having acidic groups such as acid formalin condensates and other aromatic sulfonic acid formalin condensates with basic compounds such as ammonia, organic amines, sodium hydroxide, and potassium hydroxide. .

  The nonionic resin is a water-soluble resin having no ionic functional group, and includes almost neutral water-soluble resins. Specifically, polyvinyl alcohol, polyalkylene glycol-modified acrylic resin, polyvinyl pyrrolidone, polyvinyl caprolactam, vinyl acetate-vinyl pyrrolidone copolymer, vinyl pyrrolidone-methacrylamide-vinyl imidazole copolymer, and alkylated vinyl pyrrolidone-1 -Vinylpyrrolidone resins such as butene copolymers.

<Carbon material>
The carbon material is not particularly limited as long as it has conductivity, and is a carbon material such as acetylene black, ketjen black, furnace black, graphite, graphitized carbon, carbon fiber, and fullerenes, and has a volume resistance value of 10 4 Ω · Those having high conductivity of cm or less are preferable.

<Water-based resin>
From the viewpoint of dispersion stability of the aqueous carbon material composition of the present invention and the battery electrode composition using the same, the aqueous resin used in the present invention is an aqueous resin such as rubber latex or resin emulsion. It is preferable to prepare and use as a composition. The water-based resin in the water-based carbon material composition of the present invention is not particularly limited as long as it partially dissolves in water or does not dissolve and maintains a stable state in an emulsion or the like. Examples include latex such as styrene-butadiene copolymer and vinyl chloride-vinyl acetate copolymer, and emulsion such as polytetrafluoroethylene (PTFE), styrene-acrylic acid copolymer, and acrylic acid ester copolymer. It is done. A combination of acid-modified resins may be used.

  Particularly preferred as the aqueous resin of the present invention is a cross-linked resin emulsion obtained by emulsion polymerization of a monomer containing an ethylenically unsaturated monomer having a specific functional group. When the water-based resin particles in the emulsion have a cross-linked structure with specific functional groups, they are excellent in electrolytic solution resistance, adhesion to the current collector, and flexibility, and are used as binders for secondary battery electrodes. Thus, an electrode capable of achieving charge / discharge cycle characteristics, rate characteristics, and high capacity of the battery can be obtained. The cross-linked structure of the water-based resin particles in the emulsion may be cross-linking inside the particles or cross-linking between particles, and may be cross-linked by adding a cross-linking agent separately.

  First, the case where the crosslinked structure of the water-based resin particles in the emulsion is crosslinked inside the particles will be described.

  The particle internal cross-linked resin emulsion used for the secondary battery electrode binder of the present invention is an ethylenically unsaturated monomer having an epoxy group and an ethylenic group having an alkoxysilyl group with respect to all ethylenically unsaturated monomers. 0.1 to 5.0% by weight of one or more monomers selected from the group consisting of an unsaturated monomer and an ethylenically unsaturated monomer having an N-methylol group, and an ethylenic group having a carboxyl group 0.2 to 5.0% by weight of one or more monomers selected from the group consisting of an unsaturated monomer and an ethylenically unsaturated monomer having a tertiary butyl group, and one or more other types It can obtain by carrying out emulsion polymerization of the ethylenically unsaturated monomer containing 99.7-90 weight% of ethylenically unsaturated monomers.

  At least one monomer selected from an ethylenically unsaturated monomer having an epoxy group, an ethylenically unsaturated monomer having an alkoxysilyl group, and an ethylenically unsaturated monomer having an N-methylol group is 0 When the amount is less than 1% by weight, crosslinking of the water-based resin particles in the emulsion becomes insufficient, and the resistance to electrolytic solution is deteriorated. On the other hand, if it exceeds 5.0% by weight, there will be a problem in the polymerization stability at the time of emulsion polymerization, or even if it can be polymerized, there will be a problem in storage stability.

  In addition, when at least one monomer selected from an ethylenically unsaturated monomer having a carboxyl group and an ethylenically unsaturated monomer having a tertiary butyl group is less than 0.2% by weight, The binding property with the body is weak, the electrolytic solution resistance is deteriorated, and the stability of the emulsion is also deteriorated. On the other hand, if it exceeds 5.0% by weight, the hydrophilicity after drying becomes too strong and the electrolytic solution resistance becomes poor.

  The epoxy group in the ethylenically unsaturated monomer having an epoxy group can react with a carboxyl group during polymerization and drying to introduce a crosslinked structure into the aqueous resin particles in the emulsion. At this time, the tertiary butyl group also reacts with the epoxy group in the same manner as described above because tertiary butyl alcohol is generated and a carboxyl group is formed when heat of a certain temperature or higher is applied. Examples of the ethylenically unsaturated monomer having an epoxy group include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3,4-epoxycyclohexyl (meth) acrylate, and 3,2-glycidoxyethyl (meta ) Acrylate, 3,4-epoxybutyl (meth) acrylate, 4,5-epoxypentyl methacrylate, and the like.

  Alkoxysilyl groups in the ethylenically unsaturated monomer having an alkoxysilyl group can mainly react with each other during polymerization to introduce a crosslinked structure into the aqueous resin particles in the emulsion. Examples of the ethylenically unsaturated monomer having an alkoxysilyl group include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, and γ-methacryloxypropyl. Tributoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxymethyltrimethoxysilane, γ-acryloxymethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrib Toxisilane, vinylmethyldimethoxysilane and the like can be mentioned.

  The N-methylol groups in the ethylenically unsaturated monomer having an N-methylol group can mainly react with each other during polymerization to introduce a crosslinked structure into the aqueous resin particles in the emulsion. Examples of the ethylenically unsaturated monomer having an N-methylol group include N-methylol acrylamide and N-methylol methacrylamide.

As an ethylenically unsaturated monomer having a carboxyl group, for example,
Dicarboxylic acids having an ethylenically unsaturated group such as maleic acid, fumaric acid, itaconic acid, and citraconic acid;
Alkyl or alkenyl monoesters of said dicarboxylic acids;
(Meth) acrylic acid, acrylic acid dimer, 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl isophthalate, 2- (meth) acryloyloxyethyl terephthalate, 2- (meth) acryl Leuoxypropyl phthalate, 2- (meth) acryloyloxyethyl hexahydrophthalate, 2- (meth) acryloyloxypropyl hexahydrophthalate, ethylene oxide-modified succinic acid (meth) acrylate, β-carboxyethyl (meth) acrylate, And (meth) acrylates having a carboxyl group, such as ω-carboxypolycaprolactone (meth) acrylate; and
Examples thereof include carboxylic acids having other ethylenically unsaturated groups such as crotonic acid and cinnamic acid.

  Examples of the ethylenically unsaturated monomer having a tertiary butyl group include tertiary butyl (meth) acrylate.

  Next, the case where the crosslinked structure of the water-based resin particles in the emulsion is crosslinking between particles will be described.

  The interparticle crosslinked resin emulsion used for the binder for secondary battery electrodes of the present invention has an ethylenically unsaturated monomer having a carboxyl group and a tertiary butyl group with respect to the total ethylenically unsaturated monomer. 0.5 to 10.0% by weight of one or more monomers selected from the group consisting of ethylenically unsaturated monomers and 99.5 to 90.90% of one or more other ethylenically unsaturated monomers. It can be obtained by emulsion polymerization of an ethylenically unsaturated monomer containing 0% by weight. Furthermore, in this case, a compound having a functional group capable of reacting with a carboxyl group is added as a crosslinking agent to the obtained aqueous resin emulsion, and the aqueous resin particles in the emulsion are crosslinked when dried using as a binder. be able to. The compound having a functional group capable of reacting with a carboxyl group may be added when adjusting the aqueous carbon material composition, or may be added in advance to the emulsion resin after emulsion polymerization.

  When at least one monomer selected from an ethylenically unsaturated monomer having a carboxyl group and an ethylenically unsaturated monomer having a tertiary butyl group is less than 0.5% by weight, the aqueous system in the emulsion Crosslinking of the resin particles is not sufficient, the resistance of the aqueous resin to the electrolytic solution is deteriorated, and the stability of the aqueous resin particles in the emulsion is also deteriorated. On the other hand, if it exceeds 10.0% by weight, the emulsion after adding a compound having a functional group capable of reacting with a carboxyl group while the hydrophilicity after drying becomes too strong, the electrolytic solution resistance of the aqueous resin deteriorates. The stability of the water-based resin particles in the inside deteriorates. As the ethylenically unsaturated monomer having a carboxyl group and the ethylenically unsaturated monomer having a tertiary butyl group, monomers similar to those described above are used.

  Examples of the compound having a functional group capable of reacting with a carboxyl group used as a crosslinking agent include bisphenol A-epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and glycerin diglycidyl ether. Glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, and 1,3 -Bis (N, N'-diglycidylaminomethyl) cyclohexane and the like. These compounds are preferably added in an amount of 0.1 to 10.0 parts by weight, more preferably 1.0 to 5.0 parts by weight, based on 100 parts by weight of the solid content of the emulsion.

  When the compound having a functional group capable of reacting with a carboxyl group used as a cross-linking agent is less than 0.5% by weight, cross-linking between water-based resin particles in the emulsion is not sufficient, and the resistance to electrolytic solution is deteriorated. On the other hand, if it exceeds 10.0% by weight, the stability of the aqueous resin particles in the emulsion after the addition of the compound having a functional group capable of reacting with a carboxyl group is deteriorated.

  Furthermore, another case where the cross-linked structure of the water-based resin particles in the emulsion is cross-linking between particles will be described.

  In the present invention, the interparticle cross-linked resin emulsion used for the binder for the secondary battery electrode is 0.5 to 10.0 weight percent of the unsaturated monomer having a carbonyl group with respect to the total ethylenically unsaturated monomer. % And one or more other ethylenically unsaturated monomers 90.0 to 99.5% by weight can be obtained by emulsion polymerization. Furthermore, also in this case, the resulting aqueous resin emulsion can be added with a compound having a functional group capable of reacting with a carbonyl group as a crosslinking agent, and the emulsion resin particles can be crosslinked when used as a binder and dried. . The compound having a functional group capable of reacting with a carbonyl group may be blended when the aqueous carbon material composition is prepared, or may be added in advance to the emulsion resin after emulsion polymerization.

  When the ethylenically unsaturated monomer having a carbonyl group is less than 0.5% by weight, the aqueous resin particles in the emulsion are not sufficiently cross-linked, resulting in poor electrolyte solution resistance. On the other hand, if it exceeds 10.0% by weight, the stability after addition of a compound having a functional group capable of reacting with a carbonyl group becomes poor. Examples of the ethylenically unsaturated monomer having a carbonyl group include diacetone acrylamide, diacetone methacrylamide, acrolein, N-vinylformamide, vinyl methyl ketone, vinyl ethyl ketone, acetoacetoxyethyl acrylate, acetoacetoxypropyl acrylate, Examples include acetoacetoxybutyl acrylate, acetoacetoxyethyl methacrylate, acetoacetoxypropyl methacrylate, and acetoacetoxybutyl methacrylate.

Examples of the compound having a functional group capable of reacting with a carbonyl group used as a crosslinking agent include hydrazine derivatives having at least two hydrazide groups in one molecule.
Aliphatic dihydrazides such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, and sebacic acid dihydrazide, carbonic acid polyhydrazide, aliphatic bissemicarbazide, alicyclic semicarbazide, aromatic bissemicarbazide, Dihydrazides of aromatic dicarboxylic acids, polyhydrazides of polyacrylic acid, dihydrazides of aromatic hydrocarbons, hydrazine-pyridine derivatives, and dihydrazides of unsaturated dicarboxylic acids such as maleic acid dihydrazide. These compounds are preferably added in an amount of 0.1 to 10.0 parts by weight, more preferably 1 to 5.0 parts by weight, based on 100 parts by weight of the solid content of the emulsion.

  When the compound having a functional group capable of reacting with a carbonyl group used as a crosslinking agent is less than 0.5% by weight, crosslinking between water-based resin particles in the emulsion becomes insufficient, and the resistance to electrolytic solution is deteriorated. On the other hand, if it exceeds 10.0% by weight, the stability after addition of a compound having a functional group capable of reacting with a carbonyl group is deteriorated.

Examples of one or more other ethylenically unsaturated monomers other than the ethylenically unsaturated monomer that can be used when polymerizing the crosslinked resin emulsion of the present invention include, for example,
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, pentyl (meth) acrylate, heptyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, Nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl ( (Meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, icosyl (meth) acrylate, heicosyl (meth) acrylate, docosyl Meth) linear alkyl (meth) acrylates such as acrylate;
Branched alkyl (meth) acrylates such as isopropyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isomyristyl (meth) acrylate, and isostearyl (meth) acrylate;
Cyclohexyl (meth) acrylate, Tertiarybutylcyclohexyl (meth) acrylate, Dicyclopentanyl (meth) acrylate, Dicyclopentanyloxyethyl (meth) acrylate, Dicyclopentenyl (meth) acrylate, Dicyclopentenyloxyethyl (meth) ) Acrylates and cyclic alkyl (meth) acrylates such as isobornyl (meth) acrylate;
Diolefins such as butadiene, isoprene, vinyl (meth) acrylate, divinylbenzene, allyl (meth) acrylate, ethylene glycol di (meth) acrylate;
(Meth) acrylates having a heterocyclic ring such as tetrahydrofurfuryl (meth) acrylate and 3-methyl-3-oxetanyl (meth) acrylate;
Benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, paracumylphenoxyethyl (meth) acrylate, paracumylphenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, etc. (Meth) acrylates having the following aromatic ring;
2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, diethylene glycol monomethyl ether (meth) acrylate, diethylene glycol monoethyl ether (meta ) Acrylate, triethylene glycol monomethyl ether (meth) acrylate, triethylene glycol monoethyl ether (meth) acrylate, diethylene glycol mono-2-ethylhexyl ether (meth) acrylate, dipropylene glycol monomethyl ether (meth) acrylate, tripropylene glycol mono (Meth) acrylate, polyethylene glycol monolauryl ether (meth) acrylate, and polyester Glycol monostearyl ether (meth) acrylate of (poly) alkylene glycol monoalkyl ether (meth) acrylates;
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-acryloyloxyethyl-2-hydroxyethyl (meth) Phthalates,
Diethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, propylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate,
Polytetramethylene glycol mono (meth) acrylate, poly (ethylene glycol-propylene glycol) mono (meth) acrylate, poly (ethylene glycol-tetramethylene glycol) mono (meth) acrylate, poly (propylene glycol-tetramethylene glycol) mono ( (Meth) acrylates and (meth) acrylates having hydroxyl groups such as glycerol (meth) acrylate;
Olefins having a hydroxyl group such as 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, and allyl alcohol;
(Meth) acrylates having a tertiary amino group such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and diethylaminopropyl (meth) acrylate;
Styrenes having tertiary amino groups such as dimethylaminostyrene and diethylaminostyrene;
(Meth) acrylamide, N-methoxymethyl- (meth) acrylamide, N-ethoxymethyl- (meth) acrylamide, N-propoxymethyl- (meth) acrylamide, N-butoxymethyl- (meth) acrylamide, N-pentoxymethyl -Monoalkylol (meth) acrylamide such as (meth) acrylamide, N, N-di (methylol) acrylamide, N-methylol-N-methoxymethyl (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) methacrylamide, N, N-di (butoxymethyl) acrylamide, N-butoxymethyl-N- (methoxymethyl) methacrylamide, N, N-di (pentoxymethyl) acrylamide, N-methoxymethyl-N- (Meth) acrylamides such as (pentoxymethyl) methacrylamide and dialkyrol (meth) acrylamide;
Vinylamides such as N-vinylformamide;
Perfluoromethylmethyl (meth) acrylate, perfluoroethylmethyl (meth) acrylate, 2-perfluorobutylethyl (meth) acrylate, 2-perfluorohexylethyl (meth) acrylate, 2-perfluorooctylethyl (meth) acrylate , 2-perfluoroisononylethyl (meth) acrylate, 2-perfluorononylethyl (meth) acrylate, 2-perfluorodecylethyl (meth) acrylate, perfluoropropylpropyl (meth) acrylate, perfluorooctylpropyl (meta ) Perfluoroalkyl having a C 1-20 perfluoroalkyl group such as acrylate, perfluorooctyl amyl (meth) acrylate, and perfluorooctyl undecyl (meth) acrylate Kill (meth) acrylates;
Olefin having a perfluoroalkyl group such as perfluorobutylethylene, perfluorohexylethylene, perfluorooctylethylene, and perfluorodecylethylene;
(Meth) acryloxy-modified polydimethylsiloxanes (silicone macromers);
Olefins having a polyester chain such as lactone-modified (meth) acrylate;
(Meth) acrylates having a quaternary ammonium base such as dimethylaminoethyl methyl chloride (meth) acrylate;
Trimethyl-3- (1- (meth) acrylamide-1,1-dimethylpropyl) ammonium chloride, trimethyl-3- (1- (meth) acrylamidepropyl) ammonium chloride, and trimethyl-3- (1- (meth) acrylamide (Meth) acrylamides having a quaternary ammonium base such as -1,1-dimethylethyl) ammonium chloride;
Α-olefins such as 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, and 1-hexadecene;
Fatty acid vinyls such as vinyl acetate, vinyl butyrate, vinyl propionate, vinyl hexanoate, vinyl caprylate, vinyl laurate, vinyl palmitate, vinyl stearate;
Vinyl ethers such as butyl vinyl ether and ethyl vinyl ether;
Allyls such as allyl acetate, allylbenzene, and allyl cyanide;
Other vinyls such as vinyl cyanide, vinyl cyclohexane, vinyl methyl ketone, styrene, α-methyl styrene, 2-methyl styrene, chlorostyrene;
Dienes such as butadiene and isoprene;
Olefins having two ethylenically unsaturated groups, such as divinylbenzene, vinyl (meth) acrylate, allyl (meth) acrylate, and ethylene glycol di (meth-9acrylate); and
Examples include ethynyls such as acetylene, acetyl alcohol, ethynylbenzene, and ethynyltoluene. These may be used alone or in combination of two or more.

  Among these monomers, it is possible to use at least one monomer selected from the group consisting of styrene, 2-ethylhexyl acrylate, and cyclohexyl methacrylate, which provides resistance to electrolyte, adhesion to a current collector, and flexibility. It is preferable because of its excellent properties. When using styrene, it is preferable that the usage-amount is 5 to 60 weight% in 100 weight% of ethylenically unsaturated monomers. Moreover, when using 2-ethylhexyl acrylate, it is preferable that the usage-amount is 20 to 60 weight% in 100 weight% of ethylenically unsaturated monomers. Moreover, when using cyclohexyl methacrylate, it is preferable that the usage-amount is 5 to 50 weight% in 100 weight% of ethylenically unsaturated monomers.

  The cross-linked resin emulsion of the aqueous resin used in the present invention is synthesized by a conventionally known emulsion polymerization method.

  As the emulsifier used in the emulsion polymerization, a conventionally known one such as a reactive emulsifier having an ethylenically unsaturated group and / or a non-reactive emulsifier having no ethylenically unsaturated group may be arbitrarily used. it can.

  The reactive emulsifier having an ethylenically unsaturated group can be further roughly classified into anionic and nonionic ones. Especially when anionic reactive emulsifier or nonionic reactive emulsifier having an ethylenically unsaturated group is used, the dispersion particle size of the copolymer becomes fine and the particle size distribution becomes narrow, so it is used as a binder for secondary battery electrodes. This is preferable because the resistance to electrolytic solution can be improved. This anionic reactive emulsifier or nonionic reactive emulsifier having an ethylenically unsaturated group may be used singly or in combination.

Specific examples of the anionic reactive emulsifier having an ethylenically unsaturated group are illustrated below, but the emulsifiers that can be used in the present invention are not limited to those described below. Examples of the emulsifier include alkyl ethers (commercially available products include, for example, Aqualon KH-05, KH-10, KH-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Adeka Soap SR-10N, SR-20N manufactured by ADEKA Corporation. Latemuru PD-104 manufactured by Kao Corporation);
Sulfosuccinic acid ester-based (for example, Latmul S-120, S-120A, S-180P, S-180A, Sanyo Chemical Co., Ltd., Elemiol JS-2, etc., manufactured by Kao Corporation);
Alkyl phenyl ether type or alkyl phenyl ester type (commercially available products include, for example, Aqualon H-2855A, H-3855B, H-3855C, H-3856, HS-05, HS-10, HS, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. -20, HS-30, ADEKA Corporation ADEKA rear soap SDX-222, SDX-223, SDX-232, SDX-233, SDX-259, SE-10N, SE-20N, SE-, etc.);
(Meth) acrylate sulfate ester (commercially available products such as Antox MS-60, MS-2N, Sanyo Kasei Kogyo Co., Ltd. Elminol RS-30 manufactured by Nippon Emulsifier Co., Ltd.);
Examples of the phosphoric acid ester (commercially available products include H-3330PL manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Adeka Soap PP-70 manufactured by ADEKA Co., Ltd.), and the like.

Nonionic reactive emulsifiers that can be used in the present invention include, for example, alkyl ether-based (commercially available products such as Adeka Soap ER-10, ER-20, ER-30, ER-40, manufactured by ADEKA Corporation, Latemu PD-420, PD-430, PD-450, etc. manufactured by Kao Corporation);
Alkyl phenyl ether type or alkyl phenyl ester type (commercially available products include, for example, Aqualon RN-10, RN-20, RN-30, RN-50, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ADEKA rear soap NE- manufactured by ADEKA Co., Ltd. 10, NE-20, NE-30, NE-40, etc.);
(Meth) acrylate sulfate-based (as commercial products, for example, RMA-564, RMA-568, RMA-1114, etc. manufactured by Nippon Emulsifier Co., Ltd.) can be mentioned.

  When obtaining a cross-linked resin emulsion of an aqueous resin used in the present invention by emulsion polymerization, a non-reactive emulsifier that does not have an ethylenically unsaturated group, if necessary, together with the above-described reactive emulsifier having an ethylenically unsaturated group. Can be used together. Non-reactive emulsifiers can be broadly 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;
Polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether;
Sorbitan higher fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, and sorbitan trioleate;
Polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate;
Polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate;
Glycerin higher fatty acid esters such as oleic acid monoglyceride and stearic acid monoglyceride;
Examples thereof include polyoxyethylene / polyoxypropylene / block copolymers; and polyoxyethylene distyrenated phenyl ether.

Examples of non-reactive anionic emulsifiers include higher fatty acid salts such as sodium oleate;
Alkylaryl sulfonates such as sodium dodecylbenzenesulfonate;
Alkyl sulfate salts such as sodium lauryl sulfate;
Polyoxyethylene alkyl ether sulfate ester salts such as sodium polyoxyethylene lauryl ether sulfate;
Polyoxyethylene alkylaryl ether sulfate salts such as sodium polyoxyethylene nonylphenyl ether sulfate;
Alkyl sulfosuccinic acid ester salts such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene lauryl sulfosuccinate, and derivatives thereof; and
Examples thereof include polyoxyethylene distyrenated phenyl ether sulfate salts.

  The amount of the emulsifier used in the emulsion polymerization is not necessarily limited, and is appropriately determined according to the physical properties required when the aqueous resin used in the present invention is finally used as a binder for a secondary battery electrode. You can choose. For example, the amount of the emulsifier is usually preferably 0.1 to 30 parts by weight, more preferably 0.3 to 20 parts by weight, based on 100 parts by weight of the total of ethylenically unsaturated monomers. More preferably, it is in the range of 5 to 10 parts by weight.

In emulsion polymerization, a water-soluble protective colloid can be used in combination. 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 hydroxyethylcellulose, hydroxypropylcellulose, and carboxymethylcellulose salts; and
Natural polysaccharides such as guar gum and the like can be mentioned, and these can be used alone or in a combination of plural kinds. The amount of the water-soluble protective colloid used is 0.1 to 5 parts by weight, more preferably 0.5 to 2% by weight, based on 100 parts by weight of the total amount of ethylenically unsaturated monomers.

  Examples of the aqueous medium used in the emulsion polymerization include water, and a hydrophilic organic solvent can be used as long as the object of the present invention is not impaired.

The polymerization initiator used in the emulsion polymerization is not particularly limited as long as it has the ability to initiate radical polymerization, and known oil-soluble polymerization initiators and water-soluble polymerization initiators can be used. The oil-soluble polymerization initiator is not particularly limited, for example,
Benzoyl peroxide, tert-butylperoxybenzoate, tert-butyl hydroperoxide, tert-butylperoxy (2-ethylhexanoate), tert-butylperoxy-3,5,5-trimethylhexanoate, and Organic peroxides such as di-tert-butyl peroxide; and
2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 1, Examples thereof include azobis compounds such as 1′-azobis-cyclohexane-1-carbonitrile. These can be used alone or in combination of two or more. These polymerization initiators are preferably used in an amount of 0.1 to 10.0 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer.

  In obtaining a cross-linked resin emulsion of an aqueous resin used in the present invention by emulsion polymerization, it is particularly preferable to use a water-soluble polymerization initiator from the viewpoint of emulsion stability. For example, ammonium persulfate, potassium persulfate, Conventionally known materials such as hydrogen peroxide and 2,2′-azobis (2-methylpropionamidine) dihydrochloride can be suitably used. Moreover, when performing emulsion polymerization, a reducing agent can be used together with a polymerization initiator if desired. Thereby, it becomes easy to accelerate the emulsion polymerization rate or to perform the emulsion polymerization at a low temperature. Examples of such a reducing agent include reducing organic compounds such as metal salts such as ascorbic acid, ersorbic acid, tartaric acid, citric acid, glucose, formaldehyde sulfoxylate, sodium thiosulfate, sodium sulfite, sodium bisulfite, Examples include reducing inorganic compounds such as sodium bisulfite, ferrous chloride, Rongalite, and thiourea dioxide. These reducing agents are preferably used in an amount of 0.05 to 5.0 parts by weight with respect to 100 parts by weight of the total ethylenically unsaturated monomer.

  In addition, it can superpose | polymerize by a photochemical reaction, radiation irradiation, etc. irrespective of an above described polymerization initiator. The polymerization temperature is not less than the polymerization start temperature of each polymerization initiator. For example, in the case of a peroxide-based polymerization initiator, it may be usually about 70 ° C. The polymerization time is not particularly limited, but is usually 2 to 24 hours.

  Further, if necessary, salts such as sodium acetate, sodium citrate, and sodium bicarbonate as buffering agents, octyl mercaptan, 2-ethylhexyl thioglycolate, stearyl mercaptan, lauryl mercaptan, and An appropriate amount of mercaptans such as t-dodecyl mercaptan can be used.

When a monomer having an acidic functional group such as an ethylenically unsaturated monomer having a carboxyl group is used for obtaining a cross-linked resin emulsion of an aqueous resin used in the present invention by emulsion polymerization, It can neutralize with a basic compound after superposition | polymerization. When neutralizing, ammonia or alkylamines such as trimethylamine, triethylamine, and butylamine;
Alcohol amines such as 2-dimethylaminoethanol, diethanolamine, triethanolamine, and aminomethylpropanol; and
It can be neutralized with a base such as morpholine. However, it is a highly volatile base that has a high effect on drying properties, and preferred bases are aminomethylpropanol and ammonia.

  Further, the glass transition temperature (hereinafter also referred to as Tg) of the aqueous resin in the cross-linked resin emulsion is preferably −5 to 70 ° C., and more preferably 10 ° C. to 50 ° C. When Tg is less than −5 ° C., the binder excessively covers the electrode active material, and the impedance tends to increase. On the other hand, if Tg exceeds 70 ° C., the flexibility and tackiness of the binder become poor, and the adhesion of the electrode active material to the current collector and the moldability of the electrode may be inferior. The glass transition temperature is a value obtained using a DSC (differential scanning calorimeter).

  In the present invention, the particle structure of the cross-linked resin emulsion may be a multi-layer structure, so-called core-shell particles. For example, it is possible to localize a resin obtained by mainly polymerizing a monomer having a functional group in the core part or the shell part, or to provide a difference in Tg or composition between the core and the shell, thereby providing curability and drying properties. The film forming property can be improved.

  The average particle size of the cross-linked resin emulsion is preferably 10 to 500 nm, and more preferably 30 to 200 nm, from the viewpoint of the binding property of the electrode active material and the stability of the emulsion. Further, when a large amount of coarse particles exceeding 1 μm are contained, the stability of the emulsion is impaired, so that the coarse particles exceeding 1 μm are preferably at most 5% by weight. In addition, the average particle diameter in the present invention represents a volume average particle diameter and can be measured by a dynamic light scattering method.

As described above, the aqueous resin in the aqueous carbon material composition of the present invention is an emulsion <aqueous medium>.
The aqueous medium in the aqueous carbon material composition of the present invention is not particularly limited as long as it contains water, but examples thereof include alcohol solvents and ester solvents that dissolve in water.

<Water-based carbon material composition>
The solid content (nonvolatile content) in the aqueous carbon material composition of the present invention is 1 to 60% by weight, preferably 5 to 55% by weight. If it is less than 1% by weight, it is difficult to form a stable coating film, and if it exceeds 60% by weight, it is difficult to hold it as a stable coating solution, causing problems such as gelation.

  The carbon material in the aqueous carbon material composition of the present invention is 0.5 to 50% by weight, preferably 1 to 40% by weight. If it is less than 0.5% by weight, the conductivity is not sufficient, and if it exceeds 50% by weight, the particles become too dense to be held as a stable working solution.

  The anionic resin and / or nonionic resin in the aqueous carbon material composition of the present invention is 0.01 to 50% by weight, preferably 0.05 to 30% by weight, based on the carbon material. If it is less than 0.01% by weight, the dispersion is insufficient, and if it exceeds 50%, the conductivity is impaired by covering the surface of the carbon material.

  The aqueous resin in the aqueous carbon material composition of the present invention has a solid content of 0.5 to 50% by weight, preferably 1 to 40% by weight. If it is less than 0.5% by weight, it becomes difficult to form a coating film, and if it exceeds 50% by weight, it is difficult to hold it as a stable coating solution.

<Composition for aqueous battery electrode>
By mix | blending an electrode active material with the water-system carbon material composition of this invention, it can be used as a composition for battery electrodes. The aqueous carbon material composition of the present invention can be used for a positive electrode and a negative electrode of a secondary battery such as a nickel metal hydride battery, a lithium battery, a nickel cadmium battery, and a lead storage battery, and is particularly suitable for a negative electrode of a nickel metal hydride battery. Can be used. In addition, it can also be used for energy devices, that is, electric double layer capacitors, solar cells, and the like.

  The aqueous carbon material composition of the present invention is blended with an electrode active material to form a battery electrode composition, and the battery electrode composition is applied to a current collector and dried to produce a battery electrode. Can do.

Examples of the electrode active material include cobalt acid lithium salt, manganate lithium salt, iron phosphate lithium salt, nickel hydroxide, or nickel oxyhydroxide for the positive electrode active material, and graphite, titanate for the negative electrode active material. A lithium salt or a silicon alloy. In particular, a hydrogen storage alloy used as a negative electrode of a nickel metal hydride battery is preferably used, and specific examples include LaNi ₅ , TiNi, Ti ₂ Ni, ZrNi, or MgNi. In addition, LaNi ₅ in which La is replaced with Misch metal Mm (representing a misch metal that is a mixture of rare earths) and a part of Ni is replaced with Mn, Al, Co, or the like.

  In addition to the carbon material, examples of the conductive material used in combination with the electrode active material include nickel powder, cobalt oxide, and titanium oxide.

  When the carbon-based composition of the present invention is used as a battery electrode composition, the conductive material containing the carbon material in the carbon-based composition of the present invention is 0.1 to 20 weights with respect to the electrode active material. %, And the water-based resin functioning as the binder resin is 0.1 to 20% by weight, preferably 0.5 to 10% by weight, based on the electrode active material, in solid content It is preferable to blend. If the conductive material (including the carbon material) is less than 0.1% by weight with respect to the electrode active material, the conductivity is low, and the capacity may be reduced when charging / discharging at a high rate. If the binder resin (water-based resin) is less than 0.1% by weight based on the electrode active material, the force for binding the electrode active material to the current collector is insufficient, and the electrode active material falls off. However, the capacity of the battery may be reduced, and if it exceeds 20% by weight, the resistance in the battery may increase and the capacity of the battery may decrease.

<Other additives>
In the battery electrode composition using the aqueous carbon material composition of the present invention, a film forming aid, an antifoaming agent, a leveling agent, a preservative, a pH adjusting agent, a viscosity adjusting agent and the like can be blended as necessary. When adjusting the water-based carbon material composition of the present invention, or when adjusting the water-based resin composition used in the present invention, it can be blended in advance.

  The film-forming aid is responsible for the temporary plasticization function that helps the formation of the coating film and evaporates relatively quickly after the coating film is formed, thereby improving the strength of the coating film. Is preferably a solvent having a temperature of 110 to 200 ° C. Specifically, propylene glycol monobutyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol monobutyl ether, diethylene glycol diethyl ether, dipropylene glycol monopropyl ether, carbitol, butyl carbitol, dibutyl carbitol, and benzyl alcohol An organic solvent soluble in an aqueous medium such as Among these, ethylene glycol monobutyl ether and propylene glycol monobutyl ether are particularly preferable because they have a high film forming auxiliary effect in a small amount. These film-forming aids are preferably contained in the battery electrode composition in an amount of 0.5 to 15% by weight.

  You may use a viscosity modifier 0.01 to 20weight% with respect to solid content. Examples of the viscosity modifier include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, polyacrylic acid (and its salt), oxidized starch, phosphorylated starch, and casein.

<Battery electrode>
In order to form a battery electrode, the battery electrode composition is applied to a current collector, heated and dried. As a coating method for the battery electrode composition, any coater head such as reverse roll method, comma bar method, gravure method, air knife method, etc. can be used. Infrared heaters, far-infrared heaters, etc. can be used. Moreover, after drying, it is press-molded and used as a battery electrode.

  The current collector is not particularly limited as long as it is usually used for secondary battery electrodes. For example, punching metal, expanded metal, wire mesh, foam metal, mesh metal fiber sintered body, aluminum foil, copper foil And so on.

  The battery electrode composition of the present invention can be used to produce a secondary battery electrode. For example, when assembling a nickel metal hydride battery using the battery electrode obtained as described above, a potassium hydroxide aqueous solution is used as the electrolyte, and sodium hydroxide and / or lithium hydroxide is added to the potassium hydroxide aqueous solution. Furthermore, a battery is configured using components such as a separator, a current collector, a terminal, and an insulating plate. Examples of the separator include polyethylene nonwoven fabric, polypropylene nonwoven fabric, polyamide nonwoven fabric, and those obtained by subjecting them to hydrophilic treatment.

  EXAMPLES The present invention will be described in more detail with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention. In the examples, “part” represents “part by weight” and “%” represents “% by weight”.

  The aqueous resin was synthesized by emulsion polymerization and prepared as an aqueous resin composition (emulsion).

[Example 1 of preparation of aqueous resin composition]
A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser was charged with 40 parts of ion-exchanged water and 0.2 part of Adeka Soap SR-10 (manufactured by ADEKA) as a surfactant. 10 parts of styrene, 60 parts of 2-ethylhexyl acrylate, 10 parts of methyl methacrylate, 10 parts of cyclohexyl methacrylate, 5 parts of acrylic acid, 1 part of acrylamide, 4 parts of glycidyl methacrylate, 53 parts of ion-exchanged water, and ADEKA rear soap SR- 1% of the pre-emulsion in which 1.8 parts of 10 (manufactured by ADEKA Co., Ltd.) was 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 maintaining the reaction system at 70 ° C. for 5 minutes, the remaining pre-emulsion and the remaining 5% aqueous solution of potassium persulfate were added dropwise over 3 hours while maintaining the internal temperature at 70 ° C., and stirring was further continued for 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 48% with ion-exchanged water to obtain an aqueous resin composition 1 (crosslinked resin emulsion). In addition, solid content was calculated | required by 150 degreeC 20 minute baking residue.

[Preparation Examples 2 to 4 and 8 to 9 of aqueous resin composition]
The composition shown in Table 1 was synthesized in the same manner as in Preparation Example 1 of the aqueous resin composition, and the aqueous resin compositions 2 to 4 (crosslinked resin emulsion) of Adjustment Examples 2 to 4 and aqueous resin compositions 8 to 8 were prepared. 9 (non-crosslinked resin emulsion) was obtained.

[Preparation Examples 5 and 7 of aqueous resin composition]
In the composition shown in Table 1, in the same manner as in Preparation Example 1 of the aqueous resin composition, except that 10% of the surfactant to be used is charged in a reaction vessel and the remaining 90% is used for preparation of a pre-emulsion. After emulsion polymerization, adipic acid hydrazide (compound having a functional group capable of reacting with a carbonyl group) shown in Table 1 was added to obtain aqueous resin compositions 5 and 7 (crosslinked resin emulsion). It was.

[Example 6 of preparation of aqueous resin composition]
In the composition shown in Table 1, in the same manner as in Preparation Example 1 of the aqueous resin composition, except that 10% of the surfactant to be used is charged in a reaction vessel and the remaining 90% is used for preparation of a pre-emulsion. After emulsion polymerization, carbodilite V-02 (compound having a functional group capable of reacting with a carboxyl group) shown in Table 1 was added, and an aqueous resin composition 6 (crosslinked resin) was added. Emulsion).

・カルボジライト Ｖ−０２（カルボジイミド硬化剤 日清紡績株式会社 ＮＣＮ当量６００ カルボキシル基と反応しうる官能基を有する化合物）
・アジピン酸ジヒドラジド（カルボニル基と反応しうる官能基を有する化合物）
・アデカリアソープ ＳＲ−１０：アルキルエーテル系アニオン性界面活性剤（株式会社ＡＤＥＫＡ製）
・アデカリアソープ ＥＲ−２０：アルキルエーテル系ノニオン性界面活性剤（株式会社ＡＤＥＫＡ製）
［実施例１−１］
炭素材料に密度１．０ｇ／ｍｌの時の体積抵抗値が３．３×１０^-2Ω・ｃｍのアセチレンブラックであるＨＳ１００（電気化学工業製）を選び、炭素材料１００部に対してノニオン性樹脂であるポリビニルピロリドン１．５部およびイオン交換水１００部を混合し、０．８ｍｍガラスビーズ２００部を入れたのちスキャンデックスで２時間分散処理した。更にビーズを取り除いて、水系樹脂組成物１ ２０８部とイオン交換水を加えて調整し、固形分３０％の水系炭素材料組成物１−１を得た。

Carbodilite V-02 (carbodiimide curing agent Nisshinbo Co., Ltd. NCN equivalent 600 compound having a functional group capable of reacting with a carboxyl group)
Adipic acid dihydrazide (compound having a functional group capable of reacting with a carbonyl group)
・ Adekaria soap SR-10: alkyl ether anionic surfactant (manufactured by ADEKA Corporation)
Adekaria soap ER-20: alkyl ether nonionic surfactant (manufactured by ADEKA Corporation)
[Example 1-1]
HS100 (manufactured by Denki Kagaku Kogyo), which is an acetylene black having a volume resistance value of 3.3 × 10 ⁻² Ω · cm at a density of 1.0 g / ml, is selected as the carbon material, and nonionic properties with respect to 100 parts of the carbon material After mixing 1.5 parts of polyvinyl pyrrolidone as a resin and 100 parts of ion-exchanged water, 200 parts of 0.8 mm glass beads were added, and then dispersed with Scandex for 2 hours. Further, the beads were removed and 208 parts of aqueous resin composition 1 and ion-exchanged water were added for adjustment to obtain an aqueous carbon material composition 1-1 having a solid content of 30%.

[Examples 1-2 to 1-9]
Aqueous carbon-based compositions 1-2 to 1-9 were obtained in the same manner as in Example 1-1 except that the aqueous resin composition 1 was replaced with the aqueous resin compositions 2 to 9.

[Example 2]
HS100 (manufactured by Denki Kagaku Kogyo), which is an acetylene black having a volume resistance value of 3.3 × 10 ⁻² Ω · cm at a density of 1.0 g / ml, is selected as a carbon material and neutralized with respect to 100 parts of the carbon material. 1.5 parts of sodium naphthalene sulfonate formalin condensation resin, which is an anionic resin, and 100 parts of ion-exchanged water were mixed, and 200 parts of 0.8 mm glass beads were added, followed by dispersion treatment with Scandex for 2 hours. Further, the beads were removed, 208 parts of aqueous resin composition 5 and ion-exchanged water were added for adjustment, and aqueous carbon material composition 2 having a solid content of 30% was obtained.

[Example 3]
HS100 (manufactured by Denki Kagaku Kogyo), which is an acetylene black having a volume resistance value of 3.3 × 10 ⁻² Ω · cm at a density of 1.0 g / ml, is selected as the carbon material, and nonionic properties with respect to 100 parts of the carbon material After mixing 1.5 parts of polyvinyl pyrrolidone as a resin and 100 parts of ion-exchanged water, 200 parts of 0.8 mm glass beads were added, and then dispersed with Scandex for 2 hours. Further, the beads were removed and 208 parts of aqueous resin composition 5 and ion-exchanged water were added for adjustment to obtain aqueous carbon material composition 3 having a solid content of 30%.

[Example 4]
HS100 (manufactured by Denki Kagaku Kogyo), which is an acetylene black having a volume resistance value of 3.3 × 10 ⁻² Ω · cm at a density of 1.0 g / ml, is selected as a carbon material and neutralized with respect to 100 parts of the carbon material. 1.5 parts of sodium naphthalene sulfonate formalin condensation resin, which is an anionic resin, and 100 parts of ion-exchanged water were mixed, and 200 parts of 0.8 mm glass beads were added, followed by dispersion treatment with Scandex for 2 hours. Further, the beads were removed and 208 parts of aqueous resin composition 1 and ion-exchanged water were added for adjustment to obtain aqueous carbon material composition 4 having a solid content of 30%.

[Example 5]
HS100 (manufactured by Denki Kagaku Kogyo), which is an acetylene black having a volume resistance value of 3.3 × 10 ⁻² Ω · cm at a density of 1.0 g / ml, is selected as the carbon material, and nonionic properties with respect to 100 parts of the carbon material A resin, 1.5 parts of polyvinylpyrrolidone and 100 parts of ion-exchanged water, were mixed, 200 parts of 0.8 mm glass beads were added, and then dispersed with Scandex for 2 hours. Further, the beads were removed and 208 parts of aqueous resin composition 1 and ion-exchanged water were added for adjustment to obtain aqueous carbon material composition 5 having a solid content of 30%.

In the present application, the following [Example 6] is a reference example.
[Example 6]
HS100 (manufactured by Denki Kagaku Kogyo), which is an acetylene black having a volume resistance value of 3.3 × 10 ⁻² Ω · cm at a density of 1.0 g / ml, is selected as the carbon material, and nonionic properties with respect to 100 parts of the carbon material. A resin, 1.5 parts of polyvinylpyrrolidone and 100 parts of ion-exchanged water, were mixed, 200 parts of 0.8 mm glass beads were added, and then dispersed with Scandex for 2 hours. Further, the beads were removed and adjusted by adding 204 parts of Nalstar SR-130 (Nippon A & L Co., Ltd., styrene-butadiene copolymer latex, solid content 49%) and ion-exchanged water, and an aqueous carbon material composition having a solid content of 30%. 6 was obtained.

[Comparative Example 1]
Aqueous carbon material composition in the same manner as in Example 1-1 except that 1.5 parts of polyvinyl pyrrolidone which is a nonionic resin is changed to 1.5 parts of polyallylamine (MW = 15,000) which is a cationic resin. Product 7 was obtained.

[Creation of secondary battery electrode composition and secondary battery electrode]
100 parts of hydrogen storage alloy powder having an average particle size of 37 μm and 0.5 part of carboxymethylcellulose as another binder to be used together are added to 2 parts of the obtained water-based carbon material composition, so that the total solid content becomes 50%. Thus, an appropriate amount of ion-exchanged water was added to prepare a negative electrode slurry (coating solution) as the battery electrode composition of the present invention. This slurry (coating solution) was applied to a punching metal (thickness 60 μm), dried at 120 ° C. for 1 hour, and then roll pressed to obtain a negative electrode. The thickness of the produced negative electrode was 160 μm.

  On the other hand, to 1 part of polytetrafluoroethylene powder (PTFE), 90 parts of nickel hydroxide powder, 10 parts of cobalt monoxide powder, and 2 parts of carboxymethylcellulose as a thickener are added, resulting in a total solid content of 50%. Thus, an appropriate amount of ion-exchanged water was added and kneaded to prepare a positive electrode slurry. This slurry was filled in a nickel-plated foam metal sheet, applied to both sides thereof, dried at 120 ° C. for 1 hour, and then roll pressed to obtain a positive electrode. The thickness of the produced positive electrode was 150 μm.

  With respect to the aqueous carbon material compositions 1-1 to 1-9 and 2 to 7, positive electrodes and negative electrodes were prepared by the above-described methods, and adhesion, coating solution stability, and battery characteristics were evaluated.

(Adhesion)
Using a knife on the surface of the negative electrode, six cuts were made from the composite material layer to the depth reaching the current collector, both vertically and horizontally at intervals of 2 mm, to make a grid cut. An adhesive tape was applied to the cut and immediately peeled off, and the degree of the active material falling off was determined by visual judgment. The evaluation results are shown in Table 1. The evaluation criteria are shown below.

○: “No peeling”
○ △: “Partial separation”
Δ: “Peeling at most parts”
×: “Completely peeled”
(Coating solution stability)
The prepared negative electrode electrode paste (battery electrode composition) was allowed to stand at 40 ° C. for 1 week, and the compatibility was evaluated by visual judgment for the degree of sedimentation of the active material, gelation of the solution, and cloudiness. The evaluation results are shown in Table 1. The evaluation criteria are shown below.

○: “No gelation”
○ △: “Partial gelation or cloudiness”
Δ: “Gelation in most parts”
×: “Complete gelation or sedimentation”
(Battery characteristics evaluation)
Charge / discharge cycle test of a nickel-hydrogen secondary battery incorporating a 6N aqueous potassium hydroxide solution and a separator as a positive electrode, a negative electrode, and an electrolyte prepared using aqueous carbon material compositions 1-1 to 1-9 and 2-6 Went. The discharge capacity at 100 cycles was measured with the first discharge capacity as 100%, and the rate of change was determined (the closer to 100%, the better). The evaluation results are shown in Table 1.

○: Holds discharge capacity of 98% or more Δ: Holds discharge capacity of 95% or more to less than 98% ×: Less than 95% Evaluation results are shown in Table 2.

表２から明らかなように、アニオン性樹脂及び／又はノニオン性樹脂で処理された炭素材料と、水系樹脂と、水系媒体と、を含んでなる本発明の水系炭素材料組成物を用いた電池電極用組成物は、実施例１−１〜１−９、並びに実施例２〜６では、密着性と塗液安定性のバランスが取れ、電池特性であるサイクル試験においても、１００サイクル後も放電容量の低下が抑制され、問題のない電気特性を示した。

As is apparent from Table 2, a battery electrode using the aqueous carbon material composition of the present invention comprising a carbon material treated with an anionic resin and / or a nonionic resin, an aqueous resin, and an aqueous medium. In Examples 1-1 to 1-9 and Examples 2 to 6, the composition for use had a good balance between adhesion and coating solution stability, and the battery capacity and the cycle capacity after 100 cycles were also the discharge capacity. The decrease in the resistance was suppressed, and there was no problem in electrical characteristics.

  However, in comparison with Examples 1-1 to 1-7 and Examples 2 to 5 using a cross-linked resin emulsion as an aqueous resin, Examples 1 to 8 using a non-cross-linked resin emulsion as an aqueous resin and In Example 1-9, electrical characteristics were slightly inferior, and in Example 6 in which styrene-butadiene copolymer latex was used as the aqueous resin, adhesion and electrical characteristics were slightly inferior.

  On the other hand, when the cationic resin was treated with a carbon material as in Comparative Example 1, the coating solution stability was very poor, and the evaluation of adhesion and battery characteristics was very bad.

Claims (6)

A carbon material treated with an anionic resin and / or a nonionic resin, an aqueous resin, and an aqueous medium,
The water-based resin is based on the total ethylenically unsaturated monomer
One or more types of monomers selected from the group consisting of an ethylenically unsaturated monomer having an epoxy group, an ethylenically unsaturated monomer having an alkoxysilyl group, and an ethylenically unsaturated monomer having an N-methylol group 0.1 to 5% by mass of a monomer,
0.2 to 5.0% by mass of one or more monomers selected from the group consisting of an ethylenically unsaturated monomer having a carboxyl group and an ethylenically unsaturated monomer having a tertiary butyl group;
Other one or more ethylenically unsaturated monomers from 90.0 to 99.7% by weight of,
Ethylenically unsaturated monomers emulsion polymerization was aqueous resin der Ru water based carbon material composition comprising including. A carbon material treated with an anionic resin and / or a nonionic resin, an aqueous resin, and an aqueous medium,
The water-based resin is based on the total ethylenically unsaturated monomer
0.5 to 10.0% by mass of one or more monomers selected from the group consisting of an ethylenically unsaturated monomer having a carboxyl group and an ethylenically unsaturated monomer having a tertiary butyl group;
Other one or more ethylenically unsaturated monomers from 90.0 to 99.5% by weight of,
An aqueous resin obtained by emulsion polymerization of an ethylenically unsaturated monomer containing
Furthermore, compounds with a comprise ing water-based carbon material composition having a functional group capable of reacting with carboxyl groups. A carbon material treated with an anionic resin and / or a nonionic resin, an aqueous resin, and an aqueous medium,
The water-based resin is based on the total ethylenically unsaturated monomer
0.5 to 10.0% by mass of an ethylenically unsaturated monomer having a carbonyl group;
Other one or more ethylenically unsaturated monomers from 90.0 to 99.5% by weight of,
An aqueous resin obtained by emulsion polymerization of an ethylenically unsaturated monomer containing
Furthermore, compounds with a comprise ing water-based carbon material composition having a functional group capable of reacting with a carbonyl group. The aqueous carbon material composition according to any one of claims 1 to 3 , wherein the anionic resin and / or the nonionic resin is 0.01 to 50% by mass relative to the carbon material. The aqueous carbon material composition according to any one of claims 1 to 4 , wherein the other one or more ethylenically unsaturated monomers include one or more selected from the group consisting of styrene, 2-ethylhexyl acrylate, and cyclohexyl methacrylate. The composition for battery electrodes which uses the water-system carbon material composition in any one of Claims 1-5 .