JP2011134649A - Resin fine grain for nonaqueous secondary cell electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin fine grain for nonaqueous secondary cell electrode, which is capable of providing a nonaqueous secondary cell that has excellent adherence to a current collector or an electrode, and maintains a high discharge capacity even under a high temperature environment caused by repetition of charge and discharge and heat generation. <P>SOLUTION: In the resin fine grain for nonaqueous secondary cell electrode, an ethylenically unsaturated monomer (A) having no conjugated diene structure undergoes two-step emulsion polymerization by a radical polymerization initiator in water under the existence of a surface-active agent. Difference of glass transition temperature (Tg) between a first-step polymerization product and a second-step polymerization product is 20 to 100 degrees Celsius. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to resin fine particles for non-aqueous secondary battery electrodes that are excellent in electrolytic solution resistance, binding properties, and flexibility. Furthermore, it is related with the resin fine particle for non-aqueous secondary battery electrodes which can be used suitably for the non-aqueous secondary battery excellent in charging / discharging cycling characteristics and high capacity | capacitance, and also a lithium ion secondary battery.

  In recent years, due to advances in electronic technology, the performance of electronic devices has improved, and miniaturization and portability have progressed, and the demand for secondary batteries with high energy density as the power source has increased. Secondary batteries include, for example, nickel metal hydride secondary batteries, lithium ion secondary batteries, etc. These secondary batteries are also being developed for high-capacity and long-life products due to the miniaturization and weight reduction of equipment. .

  The electrode of the secondary battery is composed of an electrode active material, a conductive additive, and a binder that binds these to a current collector. Conventionally, solvent-based fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene have been frequently used for both positive and negative electrode binder resins (non-patent documents 1 and 2). However, these fluororesins also have a feature that they are only soluble in a specific solvent such as N-methylpyrrolidone, and there are concerns about adverse effects on the human body and the environment, such as a bad odor during electrode preparation, There was also a problem of poor adhesion (Patent Document 1).

  With increasing interest in the environment, water-based binders are attracting attention. Of these, diene binders (rubbers) have been actively developed (Patent Document 2). However, since the diene binder is weak in oxidation resistance of double bonds in its structure, it is easily deteriorated on the positive electrode side where the oxidation reaction occurs and difficult to use on the positive electrode side. In addition, when the resin fine particles of rubber-based resin are mixed with the electrode active material, the conductive auxiliary agent, etc., and the resin fine particles, the resin fine particles take a high share, so that the fine particles are bound to each other and easily form an aggregate. There is also.

JP-A-4-249860 JP-A-9-320604

"Battery Handbook" published by Denki Shoin 1980 "Industrial Materials" September 2008 (Vol.56, No.9)

  INDUSTRIAL APPLICABILITY The present invention can provide a non-aqueous secondary battery that is excellent in adhesiveness with a current collector or an electrode and that retains a high discharge capacity even in a high temperature environment due to repeated charge and discharge or heat generation. The object is to provide resin fine particles for non-aqueous secondary battery electrodes. Furthermore, a non-aqueous secondary battery electrode that has little influence on the electrode active material, secures current collection, improves its utilization efficiency, and can achieve battery charge / discharge cycle characteristics, high capacity, and An object is to provide a non-aqueous secondary battery using the electrode.

That is, the first invention is a non-aqueous secondary emulsion obtained by two-stage emulsion polymerization of an ethylenically unsaturated monomer (A) having no conjugated diene structure with a radical polymerization initiator in the presence of a surfactant in water. Resin fine particles for battery electrodes,
The present invention relates to resin fine particles for non-aqueous secondary battery electrodes in which the glass transition temperature (Tg) difference between the first-stage polymerization product and the second-stage polymerization product is 20 to 100 ° C.

  In the second invention, the ethylenically unsaturated monomer (A) having no conjugated diene structure is an ethylenically unsaturated monomer (B) having a C1 to C8 linear or branched alkyl group, And / or the resin fine particles for a non-aqueous secondary battery electrode according to the first aspect of the present invention comprising an aromatic ethylenically unsaturated monomer (C) and a functional group-containing ethylenically unsaturated monomer (D). .

  The third invention relates to an ethylenically unsaturated monomer having a C1-C8 linear or branched alkyl group in a total of 100% by weight of the ethylenically unsaturated monomer (A) having no conjugated diene structure. The body (B) is 50 to 80% by weight, the aromatic ethylenically unsaturated monomer (C) is 10 to 35% by weight, and the functional group-containing ethylenically unsaturated monomer (D) is 0.1 to 0.1%. The present invention relates to the resin fine particles for a non-aqueous secondary battery electrode of the second invention, which is 5% by weight.

  Moreover, 4th invention is related with the non-aqueous secondary battery electrode formed using the resin fine particle for non-aqueous secondary battery electrodes of any one of 1st-3rd invention.

  Furthermore, the fifth invention relates to a non-aqueous secondary battery using the non-aqueous secondary battery electrode of the fourth invention.

  Furthermore, the sixth invention relates to a non-aqueous secondary battery according to the fifth invention, which is a lithium ion secondary battery.

  The resin fine particles for non-aqueous secondary battery electrode of the present invention are excellent in resistance to electrolyte, current collector, or electrode, and flexibility, and the resin fine particles for non-aqueous secondary battery electrode of the present invention By using this, it is possible to provide a long-life non-aqueous secondary battery that can reduce a decrease in discharge capacity in a charge / discharge cycle even in a high temperature environment due to heat generation.

  The resin fine particles for a non-aqueous secondary battery electrode of the present invention are obtained by two-stage emulsion polymerization of an ethylenically unsaturated monomer (A) having no conjugated diene structure. The glass transition temperature (Tg) difference from the eye polymerization product is 20 to 100 ° C., preferably 30 to 50 ° C. That is, the resin fine particles of the present invention are fine particles having a double structure composed of two layers having a Tg difference of 20 to 100 ° C. When the resin fine particles have a double structure, they have good workability derived from high Tg and high electrolytic solution resistance, and can have flexibility and high binding force derived from low Tg. Due to this feature, the resin fine particles for non-aqueous secondary batteries of the present invention are excellent in electrolytic solution resistance, adhesion to current collectors or electrodes, and flexibility. Even in this case, it is possible to provide a long-life nonaqueous secondary battery capable of reducing a decrease in discharge capacity in a charge / discharge cycle. If the Tg difference between the first-stage polymerization product and the second-stage polymerization product is less than 20 ° C., the characteristics of the first and second stages do not change so much, and the effect of the double structure does not appear. If the Tg difference between the first-stage polymerization product and the second-stage polymerization product exceeds 100 ° C., the compatibility between the two is poor and the intended physical properties are difficult to be exhibited. In the present invention, the difference in Tg between the first-stage polymerization composition and the second-stage polymerization composition may be 20 to 100 ° C., preferably 30 to 50 ° C. Even if the second stage polymerization product has a low Tg, the first stage polymerization product has a low Tg, and the second stage polymerization product has a high Tg.

  Tg in this invention can be calculated | required from the following formula described in Kyozo Kitaoka "Introduction to the synthetic resin for coating materials" (Polymer publication society).

1 / Tg = (W1 / Tg1) + (W2 / Tg2)... + (Wn / Tgn)
Here, Tg is the glass transition temperature (K) of the obtained copolymer, Tg1, Tg2, etc. are the glass transition temperatures (K) of the respective monomer homopolymers, W1, W2, etc. are the respective monomers. The weight ratio is expressed (W1 + W2 +... + Wn = 1).

  In addition, when using the monomer which has two or more ethylenically unsaturated groups demonstrated below, or the surfactant which has an ethylenically unsaturated group, it does not treat as a monomer used for the calculation of said Tg. Shall.

  As described above, the resin fine particles for a non-aqueous secondary battery electrode of the present invention are obtained by two-stage emulsion polymerization of an ethylenically unsaturated monomer (A) having no conjugated diene structure.

  Since the resin fine particles for a non-aqueous secondary battery electrode of the present invention are an aqueous dispersion, the load on the environment and the human body can be reduced. Further, since the ethylenically unsaturated monomer to be used does not have a conjugated diene structure, the oxidation resistance can be increased and the charge / discharge cycle life can be greatly extended.

  The ethylenically unsaturated monomer (A) having no conjugated diene structure refers to an ethylenically unsaturated monomer excluding the ethylenically unsaturated monomer (a) having a conjugated diene structure.

  Examples of the ethylenically unsaturated monomer (a) having a conjugated diene structure include 1,3-butadiene, isopropylene, 2-chloro-1,3-butadiene, and a chloropropylene skeleton. The monomer is not included as a component of the resin fine particles for non-aqueous secondary battery electrodes.

  Among ethylenically unsaturated monomers (A) not having a conjugated diene structure, ethylenically unsaturated monomers (B) having a C1-C8 linear or branched alkyl group, and / or aromatics It is preferable to contain an ethylenically unsaturated monomer (C) and a functional group-containing ethylenically unsaturated monomer (D).

  Among them, 50% of ethylenically unsaturated monomers (B) having a C1-C8 linear or branched alkyl group out of a total of 100% by weight of the ethylenically unsaturated monomers (A) having no conjugated diene structure. ~ 80 wt%, aromatic ethylenically unsaturated monomer (C) is 10 to 35 wt%, and functional group-containing ethylenically unsaturated monomer (D) is 0.1 to 5 wt%. Is particularly preferred.

  When the monomer (B) is less than 50% by weight, the elasticity and strength are deteriorated, and it may be impossible to follow the volume expansion or contraction in the positive electrode or the negative electrode during charge / discharge. On the other hand, if it exceeds 80% by weight, the stability of the polymerization system may be deteriorated, and there may be a problem in the adhesion to the current collector.

  On the other hand, if the monomer (C) is less than 10% by weight, the strength may be lost and the charge / discharge cycle life may be shortened. On the other hand, if it exceeds 35% by weight, the resin fine particles become hard and the flexibility and binding force are inferior, which is not preferable.

  In addition, when the monomer (D) is less than 0.1% by weight, the amount of functional groups remaining in or on the surface of the particle after polymerization is reduced, and it is not possible to sufficiently contribute to the improvement of the adhesion of the current collector. There is. Furthermore, there may be a problem in the dispersion of the electrode active material and the conductive additive. On the other hand, if it exceeds 5% by weight, there may be a problem in the polymerization stability at the time of emulsion polymerization, or even if it can be polymerized, it may cause a problem in storage stability.

Examples of the ethylenically unsaturated monomer (B) having a C1-C8 linear or branched alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl ( (Meth) acrylate, pentyl (meth) acrylate, heptyl (meth) acrylate, (meth) acrylate such as 2-ethylhexyl (meth) acrylate, vinyl ether compounds such as butyl vinyl ether and ethyl vinyl ether, 1-hexene, 1-octene and the like Can be mentioned.
The “tertiary butyl (meth) acrylate” described later is not included in the ethylenically unsaturated monomer (B) although the alkyl group has 4 carbon atoms.

  Examples of the aromatic ethylenically unsaturated monomer (C) include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, styrene, α-methylstyrene, 2-methylstyrene, chlorostyrene, allylbenzene, and ethynyl. Examples include benzene.

  Examples of the functional group of the functional group-containing ethylenically unsaturated monomer (D) include an epoxy group, an amide group, a hydroxyl group, a carboxyl group, and a tertiary butyl group (tertiary butanol is eliminated by heat to form a carboxyl group). , Sulfonic acid group, phosphoric acid group and the like. These functional groups remain in the particles and on the surface even after the production of the resin fine particles, and have the effect of improving physical properties such as the adhesion of the current collector, and at the same time, ensuring the stability during particle synthesis.

  Examples of the epoxy group-containing ethylenically unsaturated monomer include glycidyl (meth) acrylate and 3,4-epoxycyclohexyl (meth) acrylate.

As the amide group-containing ethylenically unsaturated monomer, for example, a primary amide group-containing ethylenically unsaturated monomer such as (meth) acrylamide;
Alkylol (meth) acrylamides such as N-methylolacrylamide, N, N-di (methylol) acrylamide, N-methylol-N-methoxymethyl (meth) acrylamide;
N-methoxymethyl- (meth) acrylamide, N-ethoxymethyl- (meth) acrylamide, N-propoxymethyl- (meth) acrylamide, N-butoxymethyl- (meth) acrylamide, N-pentoxymethyl- (meth) acrylamide Monoalkoxy (meth) acrylamides such as;
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- Dialkoxy (meth) acrylamides such as di (pentoxymethyl) acrylamide, N-methoxymethyl-N- (pentoxymethyl) methacrylamide;
Dialkylamino (meth) acrylamides such as N, N-dimethylaminopropylacrylamide, N, N-diethylaminopropylacrylamide;
Dialkyl (meth) acrylamides such as N, N-dimethylacrylamide and N, N-diethylacrylamide;
Examples include carbonyl group-containing (meth) acrylamides such as diacetone (meth) acrylamide.

  Examples of the hydroxyl group-containing ethylenically unsaturated monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, 4- Hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, allyl alcohol and the like can be mentioned.

  Examples of the carboxyl group-containing ethylenically unsaturated monomer include maleic acid, fumaric acid, itaconic acid, citraconic acid, or alkyl or alkenyl monoesters thereof, phthalic acid β- (meth) acryloxyethyl monoester, Isophthalic acid β- (meth) acryloxyethyl monoester, terephthalic acid β- (meth) acryloxyethyl monoester, succinic acid β- (meth) acryloxyethyl monoester, acrylic acid, methacrylic acid, crotonic acid, cinnamic An acid etc. are mentioned.

  Examples of the tertiary butyl group-containing ethylenically unsaturated monomer include tertiary butyl (meth) acrylate.

  Examples of the sulfonic acid group-containing ethylenically unsaturated monomer include vinyl sulfonic acid and styrene sulfonic acid.

  Examples of the phosphoric acid group-containing ethylenically unsaturated monomer include (2-hydroxyethyl) methacrylate acid phosphate.

  The epoxy group, amide group, hydroxyl group, carboxyl group, tertiary butyl group, sulfonic acid group, and phosphoric acid group in the functional group-containing ethylenically unsaturated monomer (D) are partially reacted during polymerization. It doesn't matter. These functional groups may react during drying and be used for cross-linking within or between particles.

Examples of monomers that can be used as the ethylenically unsaturated monomer (A) other than the above include, for example, lauryl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, and the like. An alkyl group-containing ethylenically unsaturated monomer having 10 to 18 carbon atoms;
An alicyclic ethylenically unsaturated monomer having no functional group such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate;
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, perfluorooctyl undecyl (meth) acrylate, etc. Le (meth) acrylate;
Perfluoroalkyl group-containing ethylenically unsaturated compounds such as perfluoroalkyl ethylene, perfluoroalkyl such as perfluorobutylethylene, perfluorohexylethylene, perfluorooctylethylene, and perfluorodecylethylene;
Fluoroethylenically unsaturated compounds such as tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, hexafluoropropylene;
Polyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, propoxypolyethylene glycol (meth) acrylate, n-butoxypolyethylene glycol (meth) acrylate, n-pentoxypolyethylene glycol (meth) Acrylate, phenoxypolyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, ethoxypolypropylene glycol (meth) acrylate, propoxypolypropylene glycol (meth) acrylate, n-butoxypolypropylene glycol (meth) acrylate N-Pentoxypolypropylene Recall (meth) acrylate, phenoxypolypropylene glycol (meth) acrylate, polytetramethylene glycol (meth) acrylate, methoxypolytetramethylene glycol (meth) acrylate, phenoxytetraethylene glycol (meth) acrylate, hexaethylene glycol (meth) acrylate, Ethylenically unsaturated compounds having a polyether chain such as methoxyhexaethylene glycol (meth) acrylate;
Ethylenically unsaturated compounds having a polyester chain such as lactone-modified (meth) acrylate;
(Meth) acrylic acid dimethylaminoethyl methyl chloride salt, trimethyl-3- (1- (meth) acrylamide-1,1-dimethylpropyl) ammonium chloride, trimethyl-3- (1- (meth) acrylamidopropyl) ammonium chloride, And quaternary ammonium base-containing ethylenically unsaturated compounds such as trimethyl-3- (1- (meth) acrylamide-1,1-dimethylethyl) ammonium chloride;
Carbonyl group-containing ethylenically unsaturated compounds such as acrolein, N-vinylformamide, vinyl methyl ketone, vinyl ethyl ketone, acetoacetoxyethyl (meth) acrylate, acetoacetoxypropyl (meth) acrylate, acetoacetoxybutyl (meth) acrylate;
Fatty acid vinyl compounds such as vinyl acetate, vinyl butyrate, vinyl propionate, vinyl hexanoate, vinyl caprylate, vinyl laurate, vinyl palmitate, vinyl stearate;
Α-olefin compounds such as 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene;
Allyl compounds such as allyl acetate and allyl cyanide;
Vinyl compounds such as vinyl cyanide, vinylcyclohexane, vinyl methyl ketone;
Ethynyl compounds such as acetylene and ethynyltoluene;
γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltributoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxy Propyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxymethyltrimethoxysilane, γ-acryloxymethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane And alkoxysilyl group-containing ethylenically unsaturated monomers such as vinyltributoxysilane and vinylmethyldimethoxysilane.

  Alkoxysilyl group-containing ethylenically unsaturated monomers, N-methylol group-containing ethylenically unsaturated monomers [alkylol (meth) acrylamides which are exemplary compounds of monomer (D)] It can be preferably used because it has the effect of contributing to the improvement in adhesion.

  These ethylenically unsaturated monomers (A) are used in a single amount as described above in order to adjust the polymerization stability and glass transition temperature (Tg) of the fine particles, as well as the film formability and film properties. Two or more types of body can be used in combination. Further, for example, the combined use of (meth) acrylonitrile has an effect of developing rubber elasticity.

In the present invention, a monomer having two or more ethylenically unsaturated groups can be used. Examples of monomers having two or more ethylenically unsaturated groups include allyl (meth) acrylate, 1-methylallyl (meth) acrylate, 2-methylallyl (meth) acrylate, and (meth) acrylic acid 1- Butenyl, 2-butenyl (meth) acrylate, 3-butenyl (meth) acrylate, 1,3-methyl-3-butenyl (meth) acrylate, 2-chloroallyl (meth) acrylate, (meth) acrylic acid 3 -Chlorallyl, o-allylphenyl (meth) acrylate, 2- (allyloxy) ethyl (meth) acrylate, allyl lactyl (meth) acrylate, citronellyl (meth) acrylate, geranyl (meth) acrylate, (meth) acrylic Rosinyl acid, cinnamyl (meth) acrylate, vinyl (meth) acrylate, 2- (2'-vini) (meth) acrylate (Meth) acrylic acid esters containing ethylenically unsaturated groups such as loxyethoxy) ethyl;
Fatty acid vinyl esters such as vinyl crotonate, vinyl oleate, vinyl linolenate;
Di (meth) acrylic acid ethylene glycol, di (meth) acrylic acid triethylene glycol, di (meth) acrylic acid tetraethylene glycol, tri (meth) acrylic acid trimethylolpropane, tri (meth) acrylic acid pentaerythritol, diacrylic acid Polyfunctional (meth) acrylic acid esters such as 1,1,1-trishydroxymethylethane, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxymethylpropanetriacrylic acid;
Divinyls such as divinylbenzene and divinyl adipate;
Examples include diallyls such as diallyl isophthalate, diallyl phthalate, diallyl maleate, and diallyl itaconate.

  Moreover, the resin fine particle of this invention can also form bridge | crosslinking by reaction with a crosslinking agent, when a functional group containing ethylenically unsaturated monomer (D) is used. That is, a compound having two or more functional groups capable of reacting with at least one functional group selected from an epoxy group, an amide group, a hydroxyl group, a carboxyl group, a sulfonic acid group, and a phosphoric acid group is added as a cross-linking agent. It can be set as the binder composition for secondary battery electrodes.

  Examples of the functional group that can react with the epoxy group include a carboxyl group, an acid anhydride group, a vinyl ether group, and an amino group. Examples of the functional group capable of reacting with an amide group include a carbonyl group. Moreover, an isocyanate group etc. are mentioned as a functional group which can react with a hydroxyl group. Examples of the functional group capable of reacting with a carboxyl group include an epoxy group, an aziridinyl group, a carbodiimide group, and an oxazoline group. Examples of the functional group capable of reacting with the sulfonic acid group include a hydroxyl group, an epoxy group, and an amino group. Examples of the functional group capable of reacting with a phosphate group include a hydroxyl group, an epoxy group, and an amino group.

Examples of the crosslinking agent that can be used in the present invention are shown below. Examples of the compound having two or more carboxyl groups include o-phthalic acid, isophthalic acid, terephthalic acid, 1,4-dimethylterephthalic acid, 1,3-dimethylisophthalic acid, 5-sulfo-1,3-dimethylisophthalate. Aromatic dicarboxylic acids such as acid, 4,4-biphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, norbornene dicarboxylic acid, diphenylmethane-4,4′-dicarboxylic acid, and phenylindanedicarboxylic acid ;
Aromatic dicarboxylic anhydrides such as phthalic anhydride, 1,8-naphthalenedicarboxylic anhydride, 2,3-naphthalenedicarboxylic anhydride;
Alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid;
Alicyclic dicarboxylic anhydrides such as hexahydrophthalic anhydride, 3-methyl-hexahydrophthalic anhydride, 4-methyl-hexahydrophthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride;
Aliphatic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, suberic acid, maleic acid, chloromaleic acid, fumaric acid, dodecanedioic acid, pimelic acid, citraconic acid, glutaric acid, itaconic acid And dicarboxylic acids.

  Examples of the compound having two or more acid anhydride groups include pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, oxydiphthalic dianhydride, and diphenylsulfonetetracarboxylic dianhydride. , Diphenyl sulfide tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, perylene tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, "Ricacid TMTA-C", "Ricacid MTA" manufactured by Shin Nippon Rika Co., Ltd. -10 "," Licacid MTA-15 "," Licacid TMEG series "," Licacid TDA "and the like.

  Examples of the compound having two or more vinyl ether groups include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, Tripropylene glycol divinyl ether, neopentyl glycol divinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, glycerin divinyl ether, trimethylolpropane divinyl ether, 1,4-dihydroxylcyclohexane divinyl ether, 1,4-dihydroxymethylcyclohexanedivinyl a Hydroquinone divinyl ether, ethylene oxide modified hydroquinone divinyl ether, ethylene oxide modified resorcin divinyl ether, ethylene oxide modified bisphenol A divinyl ether, ethylene oxide modified bisphenol S divinyl ether, glycerin trivinyl ether, sorbitol tetravinyl ether, trimethylolpropane trivinyl ether, Examples include pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol hexavinyl ether, dipentaerythritol polyvinyl ether, ditrimethylolpropane tetravinyl ether, and ditrimethylolpropane polyvinyl ether.

Examples of the compound having two or more amino groups include aliphatic diamines such as ethylenediamine and hexamethylenediamine;
Alicyclic diamines such as 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexyl, diaminocyclohexane, isophoronediamine;
And araliphatic diamines such as xylylenediamine and α, α, α ′, α′-tetramethylxylylenediamine.

  Examples of the compound having a carbonyl group include aldehyde compounds such as formalin and paraformaldehyde. The amide groups contained in the resin fine particles react with each other to form methylol groups when formalin is added. The obtained methylol group is used for forming a crosslinked structure.

  Examples of the compound having two or more isocyanate groups include aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, and alicyclic polyisocyanate.

  Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6 -Tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 ', 4 "-triphenylmethane triisocyanate, xylylene diisocyanate and the like can be mentioned.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also known as HMDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, and 1,3-butylene diisocyanate. , Dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and the like.

  Examples of the araliphatic polyisocyanate include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene. 1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and the like.

  Examples of the alicyclic polyisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (also known as IPDI, isophorone diisocyanate), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1, Examples include 4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanatomethyl) cyclohexane and the like.

  Moreover, the trimethylol propane adduct body of the said polyisocyanate, the trimer which has an isocyanurate ring, etc. can be used. Furthermore, polyphenylmethane polyisocyanate (also known as PAPI), naphthylene diisocyanate, and polyisocyanate-modified products thereof can be used. As the polyisocyanate-modified product, a carbodiimide group, a uretdione group, a uretoimine group, a burette group reacted with water, a group selected from isocyanurate groups, or a modified product having two or more of these groups is used. it can. A reaction product of polyol and diisocyanate can also be used as the polyfunctional isocyanate compound.

  Examples of the compound having two or more epoxy groups include bisphenol A-epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1, 6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N′-di) Glycidylaminomethyl) cyclohexane and the like.

  Examples of the compound having two or more aziridinyl groups include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxite), N, N′-toluene-2,4-bis (1-aziridine). Carboxite), bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N′-hexamethylene-1,6-bis (1-aziridinecarboxite), tri Methylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, tris-2,4,6- (1-aziridinyl) -1,3,5-triazine , Trimethylolpropane tris [3- (1-aziridinyl) propionate], trimethylolpropane tris [3- (1-azi Lysinyl) butyrate], trimethylolpropane tris [3- (1- (2-methyl) aziridinyl) propionate], trimethylolpropane tris [3- (1-aziridinyl) -2-methylpropionate], 2,2 ′ -Bishydroxymethylbutanol tris [3- (1-aziridinyl) propionate], pentaerythritol tetra [3- (1-aziridinyl) propionate], diphenylmethane-4,4-bis-N, N′-ethyleneurea, 1,6 -Hexamethylenebis-N, N'-ethyleneurea, 2,4,6- (triethyleneimino) -Syn-triazine, bis [1- (2-ethyl) aziridinyl] benzene-1,3-carboxylic acid amide, etc. Is mentioned.

  Examples of the compound having two or more carbodiimide groups include Nisshinbo Co., Ltd. Carbodilite series. Among these, Carbodilite V-02, 04, 06, E-01, 02, 03A is preferably an aqueous type or an aqueous emulsion type, and is therefore preferably compatible with the resin fine particles of the present invention. Moreover, even if it is an oily type like Carbodilite V-05, it can be used for the binder composition of this invention, for example by using surfactant and making it an aqueous dispersion.

  Examples of the compound having two or more oxazoline groups include 2'-methylenebis (2-oxazoline), 2,2'-ethylenebis (2-oxazoline), 2,2'-ethylenebis (4-methyl-2- Oxazoline), 2,2'-propylenebis (2-oxazoline), 2,2'-tetramethylenebis (2-oxazoline), 2,2'-hexamethylenebis (2-oxazoline), 2,2'-octa Methylenebis (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-phenylenebis (4-phenyl-2-oxazoline), 2,2′-m-phenylenebis ( -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) and the like.

Examples of the compound having two or more hydroxyl groups include linear aliphatics such as ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. Diols;
Branched chain aliphatic diols such as propylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol;
And cyclic diols such as 1,4-bis (hydroxymethyl) cyclohexane.

  The amount of these crosslinking agents used is preferably 0.1 to 50 parts by weight, more preferably 1 to 40 parts by weight, based on 100 parts by weight of the solid content of the resin fine particles. The addition amount of the cross-linking agent can be used to such an extent that it does not adversely affect the binder performance such as leakage of the cross-linking agent component into the electrolyte solution and variation during electrode production.

  Furthermore, two or more kinds of crosslinking agents in the binder composition can be used in combination. For example, an epoxy group reacts with a carboxyl group to generate a hydroxyl group. It is also possible to form a stronger crosslinked structure by reacting this hydroxyl group with a compound having two or more isocyanate groups.

  The crosslinking reaction between at least one functional group selected from the epoxy group, amide group, hydroxyl group, carboxyl group, sulfonic acid group, and phosphoric acid group in these resin fine particles and the functional group in the crosslinking agent strengthens the crosslinking. For the purpose of adjusting the binder performance, heat treatment may be performed as necessary at the time of electrode preparation. For example, the reaction between the carboxyl group in the resin fine particles and the epoxy group in the compound having two or more epoxy groups is preferably heat-treated at 160 ° C to 250 ° C.

  Furthermore, in addition to these crosslinking agents, the binder composition is used for the purpose of further strengthening the crosslinked structure of the binder composition, the purpose of improving the adhesion with the current collector, and the purpose of adjusting the mechanical strength of the binder. A third component can be added. As an additive for improving the adhesion with the current collector, since the current collector is mainly a metal compound, components that generally improve the metal adhesion, such as phosphoric acid, imidazole silane compounds, etc. Can be added. Further, as an additive for adjusting the mechanical strength of the binder, it is possible to blend a resin such as a polyamide resin, a polyester resin, or a polyurethane resin. These 3rd components will not be restricted to this as long as the said objective is satisfy | filled.

  The resin fine particles of the present invention are synthesized by a two-stage emulsion polymerization method. As the two-stage emulsion polymerization method, a known method can be used. For example, as the first step, the ethylenically unsaturated monomer (A) constituting the first-stage polymerization composition is emulsified in water using a surfactant. Water is charged into the reaction vessel and heated, and then polymerization is performed while dropping the emulsion and the radical polymerization initiator into the reaction vessel to obtain a first-stage polymerization composition.

  As a second step, the ethylenically unsaturated monomer (A) constituting the second-stage polymerization composition is emulsified in water using a surfactant. Subsequent to the first step, by performing the polymerization while dropping the emulsion and the radical polymerization initiator into the first-stage polymerization composition, the second-stage polymerization is performed using the first-stage polymerization composition as a core. Resin fine particles having the composition as a shell can be obtained.

  As the surfactant used in the emulsion polymerization in the present invention, known surfactants such as a reactive surfactant having an ethylenically unsaturated group and a non-reactive surfactant having no ethylenically unsaturated group can be used. Can be used arbitrarily.

  Reactive surfactants having an ethylenically unsaturated group can be further broadly classified into anionic and nonionic nonionic ones. In particular, when an anionic reactive surfactant or a nonionic reactive surfactant having an ethylenically unsaturated group is used, the dispersion particle size of the copolymer becomes fine and the particle size distribution becomes narrow. When used as a binder for battery electrodes, it is possible to improve the resistance to electrolytic solution, which is preferable. This anionic reactive surfactant or nonionic reactive surfactant having an ethylenically unsaturated group may be used singly or in combination.

Specific examples of the anionic reactive surfactant having an ethylenically unsaturated group are shown below, but the surfactants that can be used in the present invention are limited to those described below. is not. Examples of the surfactant include alkyl ethers (commercially available products include, for example, Aqualon KH-05, KH-10, KH-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ADEKA rear soap SR-10N, SR manufactured by ADEKA Corporation. -20N, LATEMUL PD-104 manufactured by Kao Corporation), etc .;
Sulfosuccinic acid ester-based (for example, LATEMUL 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 Soap SDX-222, SDX-223, SDX-232, SDX-233, SDX-259, SE-10N, SE-20N, etc. manufactured by ADEKA Corporation);
(Meth) acrylate sulfate-based (commercially available products include, for example, Antox MS-60, MS-2N, Sanyo Chemical Industries Co., Ltd., Elemiol 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., etc.)

Nonionic reactive surfactants that can be used in the present invention include, for example, alkyl ethers (commercially available products such as Adeka Soap ER-10, ER-20, ER-30, and ER- manufactured by ADEKA Corporation). 40, 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 esters (commercially available products include, for example, RMA-564, RMA-568, and RMA-1114 manufactured by Nippon Emulsifier Co., Ltd.).

  When the resin fine particles of the present invention are obtained by emulsion polymerization, a non-reactive surfactant having no ethylenically unsaturated group may be used in combination with the reactive surfactant having an ethylenically unsaturated group as described above. Can do. Non-reactive surfactants can be broadly classified into non-reactive anionic surfactants and non-reactive nonionic surfactants.

Examples of non-reactive nonionic surfactants 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, 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 include polyoxyethylene / polyoxypropylene / block copolymer, polyoxyethylene distyrenated phenyl ether, and the like.

Examples of non-reactive anionic surfactants 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 esters 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;
Examples thereof include polyoxyethylene distyrenated phenyl ether sulfate salts.

  The amount of the surfactant used in the present invention is not necessarily limited, and can be appropriately selected according to physical properties required when the resin fine particles are finally used as a binder for a non-aqueous secondary battery electrode. For example, the surfactant is usually preferably 0.1 to 30 parts by weight, more preferably 0.3 to 20 parts by weight with respect to 100 parts by weight of the total of ethylenically unsaturated monomers, More preferably, it is in the range of 0.5 to 10 parts by weight.

In the emulsion polymerization for obtaining the resin fine particles of the present invention, 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, carboxymethylcellulose salts;
Natural polysaccharides such as guar gum and the like can be mentioned, and these can be used either alone or in combination. The amount of the water-soluble protective colloid used is 0.1 to 5 parts by weight, more preferably 0.5 to 2 parts 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 for obtaining the resin fine particles of the present invention include water, and a hydrophilic organic solvent can be used as long as the object of the present invention is not impaired.

The radical polymerization initiator used for obtaining the resin fine particles of the present invention is not particularly limited as long as it has the ability to initiate radical polymerization, and a known oil-soluble polymerization initiator or water-soluble polymerization initiator is used. be able to. The oil-soluble polymerization initiator is not particularly limited, and examples thereof include benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butyl peroxy (2-ethylhexanoate), and tert-butyl peroxide. Organic peroxides such as oxy-3,5,5-trimethylhexanoate, di-tert-butyl peroxide;
2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1 Mention may be made of azobis compounds such as' -azobis-cyclohexane-1-carbonitrile. These may 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 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-methylpropionamidine) dihydrochloride and the like are conventionally known. A thing can be used conveniently. 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, thiourea dioxide, and the like. 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 also 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, sodium acetate, sodium citrate, sodium bicarbonate, etc. as a buffering agent, octyl mercaptan, 2-ethylhexyl thioglycolate, octyl thioglycolate, stearyl mercaptan, lauryl mercaptan as a chain transfer agent A suitable amount of mercaptans such as t-dodecyl mercaptan can be used.

When a monomer having an acidic functional group such as a carboxyl group-containing ethylenically unsaturated monomer is used as a raw material for the resin fine particles, it can be neutralized with a basic compound before or after polymerization. When neutralizing, ammonia or alkylamines such as trimethylamine, triethylamine, butylamine;
Alcohol amines such as 2-dimethylaminoethanol, diethanolamine, triethanolamine, aminomethylpropanol;
It can be neutralized with a base such as morpholine. However, it is a highly volatile base that is highly effective in drying, and preferred bases are aminomethylpropanol and ammonia.

  The average particle diameter of the resin fine particles is preferably 10 to 500 nm, and more preferably 30 to 250 nm, from the viewpoint of the binding property of the electrode active material and the stability of the particles. Further, when a large amount of coarse particles exceeding 1 μm are contained, the stability of the particles is impaired. Therefore, the amount of coarse particles exceeding 1 μm is 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.

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

  The binder composition for non-aqueous secondary battery electrodes containing the mold resin fine particles of the present invention contains a film forming aid, an antifoaming agent, a leveling agent, a preservative, a pH adjusting agent, a viscosity adjusting agent and the like as required. it can.

  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 an organic 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, benzyl alcohol, etc. Is mentioned. 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 binder composition in an amount of 0.5 to 15% by weight.

  You may use a viscosity modifier 1-100 weight part with respect to 100 weight part of resin fine particles. Examples of the viscosity modifier include carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, polyacrylic acid (and its salt), oxidized starch, phosphorylated starch, and casein.

  The binder composition for nonaqueous secondary battery electrodes of the present invention can be used for a positive electrode and a negative electrode of a secondary battery. In addition, it can also be used for energy devices, that is, capacitors, solar cells, and the like.

  The binder composition for a non-aqueous secondary battery electrode of the present invention comprises resin fine particles, an electrode active material, and, if necessary, a crosslinking agent. The binder composition for a non-aqueous secondary battery electrode is a current collector. A non-aqueous secondary battery electrode can be manufactured by applying to and drying.

  In the present invention, the resin fine particles are generally used in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the resin fine particles are less than 0.1 parts by weight, the force for binding the electrode active material to the current collector is insufficient, and the electrode active material may fall off and the battery capacity may be reduced. On the other hand, when the resin fine particle exceeds 20 parts by weight, the resistance in the battery may increase and the capacity of the battery may decrease.

  Examples of the electrode active material include carbonaceous materials such as carbon fluoride, graphite, natural graphite, and carbon fiber as negative electrode active materials, conductive polymers such as polyacene, and lithium-based metals such as lithium metal and lithium alloy. It is done. Examples of the positive electrode active material include oxides such as manganese, molybdenum, vanadium, titanium, and niobium, sulfides, and selenides. Moreover, a conductive material can be used in combination with an electrode active material.

  Examples of the conductive material used in combination with the electrode active material include nickel powder, cobalt oxide, titanium oxide, and carbon. Examples of carbon include acetylene black, furnace black, graphite, carbon fiber, and fullerenes. As for the usage-amount of an electroconductive material, 0.5-10 weight part is preferable with respect to 100 weight part of electrode active materials. If the amount is less than 0.5 part by weight, the conductivity is low, and the capacity when charging / discharging at a high rate of the secondary battery may decrease. The current collector is not particularly limited as long as it is normally used for a secondary battery electrode, and examples thereof include punching metal, expanded metal, wire mesh, foam metal, and reticulated metal fiber sintered body.

  In order to form a non-aqueous secondary battery electrode, the non-aqueous secondary battery electrode binder composition is applied to a current collector in the form of a slurry, heated and dried. As a method for applying the binder composition for the secondary battery electrode, any coater head such as a reverse roll method, a comma bar method, a gravure method, an air knife method, etc. can be used. A wind dryer, an infrared heater, a far infrared heater, etc. can be used.

The non-aqueous secondary battery of the present invention comprises a secondary battery electrode manufactured using the binder composition for a non-aqueous secondary battery electrode. When producing a non-aqueous secondary battery using the non-aqueous secondary battery electrode obtained as described above, for example, a carbonate solvent such as ethylene carbonate or propylene carbonate is used as the electrolyte, and LiPF ₆ is used as the electrolyte. It is preferable to use it as a lithium ion secondary battery using a lithium ion compound such as. 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 more specifically 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”.

<Production of resin fine particle aqueous dispersion>
[Example 1]
(1) First-stage polymerization In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a refluxing device, 60 parts of ion-exchanged water and ADEKA rear soap SR-10 (manufactured by ADEKA Corporation) 0.4 as a surfactant In addition, 15 parts of styrene, 65 parts of butyl acrylate, 17 parts of methyl methacrylate, 1 part of acrylic acid, 2 parts of acrylamide, 40 parts of ion-exchanged water, and ADEKA rear soap SR-10 (ADEKA CORPORATION) as a surfactant 10% of the pre-emulsion prepared by mixing 1.5 parts) 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 1.5 hours while maintaining the internal temperature at 70 ° C.

(2) Second-stage polymerization Following the polymerization in (1), 32 parts of styrene, 30 parts of butyl acrylate, 35 parts of methyl methacrylate, 1 part of acrylic acid, 2 parts of acrylamide, ion-exchanged water while maintaining the internal temperature at 70 ° C. A pre-emulsion mixed with 40 parts and 1.5 parts of Adeka Soap SR-10 (manufactured by ADEKA) as a surfactant was added dropwise over 1.5 hours, 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 45% with ion exchange water to obtain a resin fine particle water dispersion. In addition, solid content was calculated | required by 150 degreeC 20 minute baking residue.

[Examples 2 to 10 and Comparative Examples 1 to 4]
By the composition shown in Table 1, it synthesize | combined by the method similar to Example 1, and obtained resin fine particle aqueous dispersion of Examples 2-10 and Comparative Examples 1-4.

[Comparative Example 5]
A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser was charged with 60 parts of ion exchange water and 0.4 part of Adeka Soap SR-10 (manufactured by ADEKA) as a surfactant, 20 parts of styrene, 45 parts of butyl acrylate, 32 parts of methyl methacrylate, 1 part of acrylic acid, 2 parts of acrylamide, 40 parts of ion-exchanged water, and 1.5 parts of Adeka Soap SR-10 (manufactured by ADEKA Corporation) as a surfactant An additional 10% of the premixed pre-emulsion was 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 45% with ion exchange water to obtain a resin fine particle water dispersion. In addition, solid content was calculated | required by 150 degreeC 20 minute baking residue.

[Comparative Example 6]
An autoclave equipped with a stirrer and a dropping device was charged with 70 parts of ion-exchanged water and 0.3 part of potassium persulfate, the gas phase part was replaced with nitrogen gas for 15 minutes, and the temperature was raised to 80 ° C. On the other hand, 40 parts of acrylonitrile, 47 parts of butadiene and 3 parts of itaconic acid were charged in a separate container and dropped into the autoclave over 15 hours. During the dropping, the reaction was carried out at 80 ° C. After completion of dropping, the reaction was further terminated by stirring at 85 ° C. for 5 hours. After cooling to 30 ° C., the pH was adjusted to 7 with 25% aqueous ammonia, then steam was introduced to remove residual monomers, and then concentrated to obtain a resin fine particle aqueous dispersion having a solid content of 48%.

[Comparative Example 7]
In an autoclave equipped with a stirrer, 100 parts of ion-exchanged water, 0.08 part of methyl cellulose, 0.25 part of ethyl acetate, 0.4 part of diisopropyl peroxydicarbonate, 39.6 parts of vinylidene fluoride, 0.1% maleic acid monomethyl ester. 4 parts were charged and suspension polymerization was carried out at 28 ° C. for 47 hours. After the polymerization was completed, the polymer slurry was dehydrated, washed with water and dehydrated, and then dried at 80 ° C. for 20 hours to obtain a polymer powder. The obtained vinylidene fluoride resin was dissolved in N-methyl-2-pyrrolidone to a solid content of 10% to obtain a resin solution.

<Preparation of nonaqueous secondary battery electrode binder composition and nonaqueous secondary battery electrode>
(Preparation of positive electrode)
4700 parts of lithium cobaltate (LiCoO ₂ ) as a positive electrode active material, 100 parts of acetylene black, with respect to 100 parts of the solid content of the resin fine particle aqueous dispersions obtained in Examples 1 to 10 and Comparative Examples 1 to 6, 100 parts of carboxymethylcellulose was added as a thickener, ion-exchanged water was added so as to have a solid content of 50%, and then kneaded to prepare a binder composition for a non-aqueous secondary battery electrode. This non-aqueous secondary battery electrode binder composition was applied onto a 20 μm thick aluminum foil serving as a current collector using a doctor blade, dried by heating under reduced pressure, rolled by a roll press, and 50 μm thick. A positive electrode having a positive electrode mixture layer was prepared.

To 100 parts of the solid content of the resin solution obtained in Comparative Example 7, 4700 parts of lithium cobaltate (LiCoO ₂ ) as a positive electrode active material, 100 parts of acetylene black, and 100 parts of carboxymethyl cellulose as a thickener were added. Finally, the binder composition was adjusted so that the solid content was 50%, and kneaded to prepare a binder composition for a non-aqueous secondary battery electrode. This non-aqueous secondary battery electrode binder composition was applied onto a 20 μm thick aluminum foil serving as a current collector using a doctor blade, dried by heating under reduced pressure, rolled by a roll press, and 50 μm thick. A positive electrode having a positive electrode mixture layer was prepared.

(Preparation of negative electrode)
Mesophase carbon (MCMB 6-28, average particle size of 5 to 7 μm, specific surface area) as a negative electrode active material with respect to 100 parts of the solid content of the resin fine particle aqueous dispersions obtained in Examples 1 to 10 and Comparative Examples 1 to 6 4m ² / g Osaka Gas Chemical Co., Ltd.) 4800 parts, 100 parts of acetylene black were added, ion-exchanged water was added to a solid content of 50%, and then kneaded to form a binder composition for non-aqueous secondary battery electrodes. Was prepared. This non-aqueous secondary battery electrode binder composition was applied onto a 20 μm thick aluminum foil serving as a current collector using a doctor blade, dried by heating under reduced pressure, rolled by a roll press, and 50 μm thick. A negative electrode having a negative electrode mixture layer was prepared.

With respect to 100 parts of solid content of the resin solution obtained in Comparative Example 7, mesophase carbon (MCMB 6-28, average particle size 5 to 7 μm, specific surface area 4 m ² / g manufactured by Osaka Gas Chemical Co., Ltd.) 4800 as a negative electrode active material Part and 100 parts of acetylene black were added to adjust the final solid content of the binder composition to 50% and kneaded to prepare a binder composition for a non-aqueous secondary battery electrode. This non-aqueous secondary battery electrode binder composition was applied onto a 20 μm thick aluminum foil serving as a current collector using a doctor blade, dried by heating under reduced pressure, rolled by a roll press, and 50 μm thick. A negative electrode having a negative electrode mixture layer was prepared.

<Assembly of lithium secondary battery positive electrode evaluation cell>
A separator made of a porous polypropylene film between the working electrode and the counter electrode (# 2400, manufactured by Celgard Co., Ltd.) with the positive electrode produced previously punched into a diameter of 9 mm and used as a working electrode, and a metal lithium foil (thickness 0.15 mm) as a counter electrode Is inserted and laminated, and filled with an electrolyte (nonaqueous electrolyte in which LiPF ₆ is dissolved at a concentration of 1M in a mixed solvent of ethylene carbonate and diethyl carbonate mixed in 1: 1 (weight ratio)), and is a two-pole sealed metal A cell (HS flat cell manufactured by Hosensha) was assembled. The cell was assembled in a glow box substituted with argon gas, and after the cell was assembled, predetermined battery characteristics were evaluated.

<Assembly of lithium secondary battery negative electrode evaluation cell>
A separator made of a porous polypropylene film between the working electrode and the counter electrode (# 2400, manufactured by Celgard Co., Ltd.) with the negative electrode prepared previously having a punching working electrode with a diameter of 9 mm and a metal lithium foil (thickness 0.15 mm) as a counter electrode Is inserted and laminated, and filled with an electrolyte (nonaqueous electrolyte in which LiPF ₆ is dissolved at a concentration of 1M in a mixed solvent of ethylene carbonate and diethyl carbonate mixed in 1: 1 (weight ratio)), and is a two-pole sealed metal A cell (HS flat cell manufactured by Hosensha) was assembled. The cell was assembled in a glow box substituted with argon gas, and after the cell was assembled, predetermined battery characteristics were evaluated.

  Using the lithium ion secondary battery electrode and lithium ion secondary battery electrode evaluation cell obtained by the above method, the binding property, electrolytic solution resistance, and battery characteristics were evaluated.

(Binding property)
Using a knife on the electrode surface, 6 incisions were made from the mixture 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 criteria are shown below. The evaluation results are shown in Table 2.
○: “No peeling”
○ △: “Slightly peeled off (a level with no practical problem)”
△ ×: “Peeling at most parts”
×: “Completely peeled”

(Electrolytic solution resistance)
The prepared electrode was immersed in a propylene carbonate solution at 70 ° C. for 24 hours, and the swelling state of the film and the elution state of the resin before and after the immersion were calculated as follows for comparative evaluation.
Swelling rate (%) = (weight after immersion) / (weight before immersion)
Dissolution rate (%) = (weight after immersion drying) / (weight before immersion) -1
As the swelling rate is closer to 100% and the dissolution rate is closer to 0%, the resistance to electrolytic solution is higher. The evaluation results are shown in Table 2.

(Battery characteristics evaluation)
The charge / discharge cycle test of the lithium ion secondary battery electrode evaluation cell produced above was performed. The discharge capacity at the first time was set to 100%, and the discharge capacity after 100 hours at 70 ° C. was measured to obtain the rate of change (the closer to 100%, the better). The evaluation results are shown in Table 2.

  As shown in Table 2, when the non-aqueous secondary battery electrode binder composition containing resin fine particles synthesized in Examples 1 to 10 was used, the balance between the electrolytic solution resistance and the binding property was achieved, and the battery characteristics were However, the decrease in the discharge capacity is suppressed even after 100 hours at 70 ° C. Among them, Examples 1 to 5 [ethylenically unsaturated monomer having a C1 to C8 linear or branched alkyl group in a total of 100% by weight of the ethylenically unsaturated monomer (A) having no conjugated diene structure) The body (B) is 50 to 80% by weight, the aromatic ethylenically unsaturated monomer (C) is 10 to 35% by weight, and the functional group-containing ethylenically unsaturated monomer (D) is 0.1 to 0.1%. Particularly good results were obtained with resin fine particles of 5% by weight. On the other hand, when the resin fine particles synthesized in Comparative Examples 1 to 7 and the binder composition for a non-aqueous secondary battery electrode containing a resin solution are used, the electrolytic solution resistance and the binding property are deteriorated, and the battery characteristics are deteriorated. Also got up.

Claims (6)

Resin fine particles for a non-aqueous secondary battery electrode obtained by two-stage emulsion polymerization of an ethylenically unsaturated monomer (A) having no conjugated diene structure in water with a radical polymerization initiator in the presence of a surfactant. ,
Resin fine particles for non-aqueous secondary battery electrodes in which the glass transition temperature (Tg) difference between the first-stage polymerization product and the second-stage polymerization product is 20 to 100 ° C.   The ethylenically unsaturated monomer (A) having no conjugated diene structure is an ethylenically unsaturated monomer (B) having a C1 to C8 linear or branched alkyl group, and / or aromatic ethylene. The resin fine particle for non-aqueous secondary battery electrodes of Claim 1 containing a functional unsaturated monomer (C) and a functional group containing ethylenically unsaturated monomer (D).   50 to 80 ethylenically unsaturated monomers (B) having a C1 to C8 linear or branched alkyl group in a total of 100% by weight of the ethylenically unsaturated monomers (A) having no conjugated diene structure The aromatic ethylenically unsaturated monomer (C) is 10 to 35% by weight, and the functional group-containing ethylenically unsaturated monomer (D) is 0.1 to 5% by weight. The resin fine particle for non-aqueous secondary battery electrodes as described.   A non-aqueous secondary battery electrode comprising the resin fine particles for a non-aqueous secondary battery electrode according to claim 1.   A non-aqueous secondary battery using the non-aqueous secondary battery electrode according to claim 4.   The non-aqueous secondary battery according to claim 5, wherein the non-aqueous secondary battery is a lithium ion secondary battery.