JP2008287888A - Non-aqueous electrolyte secondary battery coating composition - Google Patents

Abstract

To provide a separator for a non-aqueous electrolyte secondary battery having high porosity, high strength and excellent reliability at high temperatures.

A polymer emulsion (A) containing at least a polymer compound (a1) which exhibits hydrophilicity in a temperature range below a certain temperature (temperature sensitive point) and exhibits hydrophobicity in a temperature range above the temperature sensitive point. And a fine particle (B). A coating composition for a non-aqueous electrolyte secondary battery.
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Description

  The present invention relates to a coating composition for a non-aqueous electrolyte secondary battery that can provide a separator for a non-aqueous electrolyte secondary battery having high porosity, high strength, and excellent reliability at high temperatures.

In recent years, nonaqueous electrolyte secondary batteries, particularly lithium ion secondary batteries, are widely used as batteries for personal computers, mobile phones, personal digital assistants, and the like because of their high energy density.
However, while the energy density is high, when the battery is damaged, internal and external short circuits occur, resulting in large heat generation. As described above, securing the safety when heat is generated above a certain level is cited as an important issue. In order to solve this problem, a polyolefin porous membrane separator that prevents contact between electrodes is usually used. However, because the separator is made of polyolefin, the dimensional stability at high temperatures is insufficient. In some cases, the positive electrode and the negative electrode may be in direct contact with each other due to deformation, etc., which is not sufficient to ensure safety.
For this reason, a method of forming an inorganic porous film having high heat resistance on the separator surface has been proposed. For example, Patent Documents 1 and 2 propose a technique for holding inorganic fine particles as a matrix material with a resin component. However, since the disclosed resin component has a weak interaction with inorganic fine particles, there is a problem in film strength. Patent Document 3 proposes a method of applying or laminating a composition comprising a water-soluble polymer and fine particles to a separator. However, when a water-soluble polymer is used, the pores are blocked, and the function as a separator is not sufficient.

Further, as a technique for forming such a porous film, a method of forming a positive electrode layer and a negative electrode layer among members of a non-aqueous electrolyte secondary battery has been well known. For example, Patent Document 4 proposes a method in which an active material is formed into a film using an emulsion and a compound having a cloud point (for example, a nonionic surfactant or a thermosensitive polymer) as a binder. In this method, since the emulsion and the thermosensitive polymer are only mixed as the binder, the interaction between the binder emulsion and the thermosensitive polymer is relatively weak, and the coating strength is not sufficient.
Patent Document 5 proposes a method using a copolymer of N-alkylacrylamide as a thermoreversible thickener. However, the interaction with the metal salt used in combination is weak and it cannot be said that sufficient coating strength can be obtained.
Patent Document 6 discloses an inorganic filler and a dispersible thermally crosslinkable resin. However, since the interaction between the resin and the inorganic filler is weak in the process until curing, a homogeneous void is formed. It cannot be said that the coating film strength is uneven.
On the other hand, Patent Document 7 discloses a recording medium in which an emulsion having a temperature sensitive point and inorganic fine particles are coated on paper, but there is no disclosure as a coating composition for a non-aqueous electrolyte secondary battery. .

JP 2001-319634 A JP 2002-8730 A JP 2004-227972 A JP 2006-260782 A JP 2003-331848 A JP-A-2005-353584 WO2002-85634 pamphlet

  An object of the present invention is to provide a separator for a non-aqueous electrolyte secondary battery that has high porosity, high strength, and excellent reliability at high temperatures.

As a result of intensive studies aimed at solving the above problems, the present inventors have reached the present invention.
That is, the present invention is as follows.

(1) a polymer emulsion (A) containing at least a polymer compound (a1) that exhibits hydrophilicity in a temperature region below a certain temperature (temperature sensing point) and exhibits hydrophobicity in a temperature region exceeding the temperature sensing point; A coating composition for a nonaqueous electrolyte secondary battery, comprising fine particles (B). (2) The polymer emulsion (A) has a hydroxyl group, a blocked hydroxyl group, a carbonyl group, a carboxyl group, a blocked carboxyl group, a carboxylic acid anhydride group, an amino group, a cyclocarbonate group, an epoxy group, and a hydrolyzable silyl. 2. A crosslinking agent (C) containing at least one reactive functional group selected from the group consisting of a group and a silanol group, and having a functional group that reacts with the reactive functional group. The coating composition for non-aqueous electrolyte secondary batteries.

(3) The non-aqueous electrolyte secondary solution according to (1) or (2), wherein the polymer emulsion (A) is obtained by polymerization in the presence of polyvinyl alcohol and / or a polyvinyl alcohol derivative. Battery coating composition.
(4) At least one coating layer made of the coating composition for a non-aqueous electrolyte secondary battery according to any one of (1) to (3) is laminated on at least one side of the support. A separator for a non-aqueous electrolyte secondary battery.
(5) The separator for a nonaqueous electrolyte secondary battery according to (4), wherein the support is a polyolefin porous film.
(6) A non-aqueous electrolyte secondary battery comprising the non-aqueous electrolyte secondary battery separator according to (4) or (5).

  The coating composition for a non-aqueous electrolyte secondary battery of the present invention can provide a separator for a non-aqueous electrolyte secondary battery having high porosity, high strength and excellent reliability at high temperatures.

Hereinafter, the present invention will be described in detail.
The polymer compound (a1) used in the present invention exhibits hydrophilicity in a temperature range below a certain temperature (temperature sensitive point) and exhibits hydrophobicity in a temperature range exceeding the temperature sensitive point, and is polymerized by homopolymerization to the temperature. Homopolymeric polymer of monomer (main monomer (M)) or copolymerized polymer of two or more main monomers (M) from which a polymer compound exhibiting responsiveness (change in hydrophilicity-hydrophobicity) is obtained Further, a monomer (submonomer (N)) that can react with the main monomer (M) to produce a polymer compound and that does not yield a polymer compound exhibiting the temperature responsiveness by homopolymerization. It is a copolymerized polymer compound with the monomer (M). The main monomer (M) and the submonomer (N) can be used alone or in combination of two or more.
A polymer compound having high temperature responsiveness can be obtained by homopolymerization, but by performing the copolymerization, a polymer compound having a temperature sensitive point different from that of the homopolymer polymer compound can be obtained, or a homopolymer polymer A film forming property different from that of the compound may be obtained.

The main monomer (M) is an N-alkyl or N-alkylene-substituted (meth) acrylamide derivative (where (meth) acryl is a simple notation of methacryl (or methacryl) or acryl), vinylmethyl Specific examples include N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-cyclopropyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-diethyl. Acrylamide, N, N-dimethyl (meth) acrylamide, Nn-propyl (meth) acrylamide, N-methyl-Nn-propylacrylamide, N-methyl-N-isopropylacrylamide, N- (meth) acryloylpyrrolidine, N- (meth) acryloylpiperidine, N-tetrahydrofurfuryl (Meth) acrylamide, N-methoxypropyl (meth) acrylamide, N-ethoxypropyl (meth) acrylamide, N-isopropoxypropyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide, N- (2,2-dimethoxy Ethyl) -N-methylacrylamide, N-methoxyethyl (meth) acrylamide, N- (meth) acryloylmorpholine and the like. From the viewpoint of film formability, N-isopropylacrylamide, Nn-propylacrylamide, N, N-diethylacrylamide, and N-acryloylmorpholine are preferable.

As the secondary monomer (N), one or more of ethylenically unsaturated monomers can be used in combination. Specifically, (meth) acrylic acid ester, (meth) acrylamide monomer, cyanide Examples of (meth) acrylic acid esters include (meth) acrylic acid alkyl esters having 1 to 18 carbon atoms in the alkyl moiety, and (meth) acrylic having 1 to 18 carbon atoms in the alkyl moiety. Acid hydroxyalkyl ester, (poly) oxyethylene (meth) acrylate having 1 to 100 ethylene oxide groups, (poly) oxypropylene (meth) acrylate having 1 to 100 propylene oxide groups, ethylene oxide groups Examples thereof include (poly) oxyethylene di (meth) acrylate having a number of 1 to 100. Specific examples of (meth) acrylic acid alkyl esters having 1 to 18 carbon atoms in the alkyl part include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and (meth) acrylic. Examples include 2-ethylhexyl acid, cyclohexyl (meth) acrylate, methyl cyclohexyl (meth) acrylate, dodecyl (meth) acrylate, and the like. Specific examples of the (meth) acrylic acid hydroxyalkyl ester having 1 to 18 carbon atoms in the alkyl part include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid 2 -Hydroxycyclohexyl, dodecyl (meth) acrylate, and the like. Specific examples of the (poly) oxyethylene (meth) acrylate having 1 to 100 ethylene oxide groups include ethylene glycol (meth) acrylate, ethylene glycol methoxy (meth) acrylate, diethylene glycol (meth) acrylate, methoxy Examples include (meth) acrylic acid diethylene glycol, (meth) acrylic acid tetraethylene glycol, and methoxy (meth) acrylic acid tetraethylene glycol. Specific examples of the (poly) oxypropylene (meth) acrylate having 1 to 100 propylene oxide groups include propylene glycol (meth) acrylate, propylene glycol methoxy (meth) acrylate, and dipropylene (meth) acrylate. Glycol, methoxy (meth) acrylic acid dipropylene glycol, (meth) acrylic acid tetrapropylene glycol, methoxy (meth) acrylic acid tetrapropylene glycol and the like. Specific examples of (poly) oxyethylene di (meth) acrylate having 1 to 100 ethylene oxide groups include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and diethylene glycol methoxy (meth) acrylate. And tetraethylene glycol di (meth) acrylate.

Examples of (meth) acrylamide monomers include (meth) acrylamide, N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone acrylamide, methylene bisacrylamide, 2-methyl-5-vinylpyridine, N-vinyl-2-pyrrolidone, N-acryloylpyrrolidine and the like can be mentioned. Examples of vinyl cyanides include (meth) acrylonitrile. Specific examples other than the above include, for example, olefins such as ethylene, propylene and isobutylene, dienes such as butadiene, haloolefins such as vinyl chloride and vinylidene chloride, vinyl acetate, vinyl propionate, vinyl n-butyrate, and benzoate. Carboxylic acid vinyl esters such as vinyl acid, vinyl pt-butylbenzoate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl versatate, vinyl laurate, carboxylic acids such as isopropenyl acetate and isopropenyl propionate Alipropenyl esters, vinyl ethers such as ethyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether, styrene derivatives such as styrene and methyl styrene, aromatic vinyl compounds such as vinyl toluene, allyl acetate, allyl benzoate, etc. Esters, allyl ethers such as allyl ethyl ether, allyl glycidyl ether, allyl phenyl ether, γ- (meth) acryloxypropyltrimethoxysilane, vinylmethyldiethoxysilane, vinylmethyldimethoxysilane, vinyldimethylethoxysilane, vinyl Dimethylmethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6 6-pentamethylpiperidine, perfluoromethyl (meth) acrylate, perfluoropropyl (meth) acrylate, perfluoropropylmethyl (meth) acrylate, vinylpyrrolidone, trimethylolpropane tri (meth) acrylate Glycidyl (meth) acrylate, 2,3-cyclohexene oxide (meth) acrylate, allyl (meth) acrylate, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxypropyl methacrylate, methylpropanesulfonic acid Carboxylic acid group-containing monomers such as acrylamide, divinylbenzene, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, crotonic acid, butenetricarboxylic acid, monoethyl maleate, monomethyl maleate, monoethyl itaconate, monomethyl itaconate, Sulfonic acid group-containing monomers such as 2-acrylamido-2-methyl-propanesulfonic acid, styrenesulfonic acid, vinylsulfonic acid, (meth) acrylsulfonic acid, N, N-dimethylaminoethyl (meth) acrylate, N, N- The Amino group-containing monomers such as chill aminoethyl (meth) acrylate.
In particular, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, styrene, (meth) acrylamide, diacetone acrylamide Methylenebisacrylamide, acrylic acid, methacrylic acid, itaconic acid, fumaric acid and maleic acid are preferred. Here, (meth) acryl is a simple description of methacryl (or methacryl) or acryl.

A cationic group-containing monomer can also be used in order to impart blending stability in accordance with the characteristics of the fine particles (B) of the present invention. More preferably, the monomer having a cationic group contains a tertiary amino group and / or a quaternary ammonium base.
The polymer compound (a1) containing a tertiary amino group and / or a quaternary ammonium base contains, for example, a main monomer (M) and a tertiary amino group and / or a quaternary ammonium base as a submonomer (N). It is obtained by copolymerizing with a monomer. The main monomer (M) and submonomer (N) (including monomers containing a tertiary amino group and / or a quaternary ammonium base) can be used alone or in combination of two or more. The tertiary amino group or quaternary ammonium base-containing monomer is not particularly limited as long as it has a structure containing a tertiary amino group or quaternary ammonium base in the monomer, but vinyloxyethyltrimethylammonium chloride, 2, 3 -Dimethyl-1-vinylimidazolinium chloride, trimethyl- (3- (meth) acrylamide-3,3-dimethylpropyl) ammonium chloride, trimethyl- (3-methacrylamidopropyl) ammonium chloride, trimethyl- (3-acrylamidopropyl) ) Ammonium chloride, N- (1,1-dimethyl-3-dimethylaminopropyl) (meth) acrylamide and its quaternary ammonium salt, trimethyl- (3- (meth) acrylamide) ammonium chloride, 1-vinyl-2-methyl -Imidazole, 1-vinyl-2- Tyl-imidazole, 1-vinyl-2-phenyl-imidazole, 1-vinyl-2,4,5-trimethyl-imidazole, N, N-dimethylaminopropyl (meth) acrylate and its quaternary ammonium salt, N, N- Dimethylaminoethyl (meth) acrylate and its quaternary ammonium salt, N, N-diethylaminoethyl (meth) acrylate and its quaternary ammonium salt, t-butylaminoethyl (meth) acrylate and its quaternary ammonium salt, N- ( 3-dimethylaminopropyl) methacrylamide and its quaternary ammonium salt, N- (3-dimethylaminopropyl) acrylamide and its quaternary ammonium salt, N- (3-diethylaminopropyl) methacrylamide and its quaternary ammonium salt, N -(3-Diethylaminopropyl) acrylamide and As quaternary ammonium salts, o-, m-, p- aminostyrene and its quaternary ammonium salts, o-, m-, p- vinylbenzyl amines and their quaternary ammonium salts, N- (vinylbenzyl) pyrrolidone, N
-(Vinylbenzyl) piperidine, N-vinylimidazole and its quaternary ammonium salt, 2-methyl-1-vinylimidazole and its quaternary ammonium salt, N-vinylpyrrolidone and its quaternary ammonium salt, N, N'-divinyl Ethyleneurea and its quaternary ammonium salt, α- or β-vinylpyridine and its quaternary ammonium salt, α- or β-vinylpiperidine and its quaternary ammonium salt, 2- or 4-vinylquinoline and its quaternary ammonium salt Etc. are exemplified. In particular, a methyl chloride quaternary compound of N, N-dimethylaminopropyl methacrylate, N, N-dimethylaminoethyl methacrylate, N, N-dimethylaminopropyl (meth) acrylamide is preferably used.

The copolymerization ratio of the main monomer (M) and the submonomer (N) is such that the hydrophilicity and hydrophobicity of the obtained copolymeric polymer compound are reversible at a certain temperature (ie, “temperature sensitive point”). It is determined within a range exhibiting changing temperature responsiveness. That is, if the proportion of the submonomer (N) is too large, the copolymeric polymer compound obtained does not exhibit the temperature responsiveness.
That is, the copolymerization ratio of the main monomer (M) and the submonomer (N) depends on the combination of the monomer species used, but the ratio of the submonomer (N) in the resulting polymer compound is preferably 50% by mass or less. More preferably, it is 30 mass% or less.
Further, the content of the anion group and cation group-containing monomer in the polymer compound (a1) is not particularly limited within the range of the above conditions, but is 0.01% by mass from the viewpoint of ease of preparation of the coating liquid. The above is preferable, and from the viewpoint of film formability, 50% by mass or less is preferable. More preferably, it is 0.1-30 mass%.

  In the present invention, the “temperature sensitive point” of the polymer compound (a1) is a temperature at which its hydrophilicity-hydrophobicity changes, and “temperature responsiveness” indicates a change in the hydrophilicity-hydrophobicity. Means nature. In the present invention, the term “hydrophilic” means that the polymer compound (a1) in a system in which the polymer compound (a1) and water coexist is more stable in a state compatible with water than in a phase separated state. In the system in which the polymer compound (a1) and water coexist, the “hydrophobic” means that the polymer compound (a1) is in a state of being phase-separated with water rather than in a state of being compatible. Means stable. The change in hydrophilicity-hydrophobicity is, for example, an abrupt viscosity change accompanying a temperature change in a system in which the polymer compound (a1) and water coexist, or transparency in a system in which the polymer compound (a1) and water coexist. Or a rapid change in the solubility of the polymer compound (a1) in water. That is, the viscosity when the temperature of the system in which the polymer compound (a1) and water coexist is gradually lowered from the temperature range where the polymer compound (a1) exhibits hydrophobicity (temperature exceeding the temperature sensitive point). The polymer compound (a1) obtained as a transition point at which the temperature-viscosity curve obtained by measurement changes abruptly or in a temperature range where the polymer compound (a1) exhibits hydrophobicity (temperature exceeding the temperature sensitive point) The temperature sensitive point of the polymer compound (a1) can be determined as the temperature at which the dispersion begins to become transparent or gel when the aqueous dispersion is gradually cooled.

The polymer emulsion (A) of the present invention has a temperature (temperature sensitive point) at which a viscosity change is abruptly caused by the influence of a change in hydrophilicity-hydrophobicity due to a temperature change of the polymer compound (a1) contained. That is, the viscosity when the temperature of the polymer emulsion (A) of the present invention is gradually lowered from the temperature range where the polymer compound (a1) contained in the emulsion exhibits hydrophobicity (temperature exceeding the temperature sensitive point). As a transition point where the temperature-viscosity curve obtained by measuring the abrupt change, or the temperature of the polymer emulsion (A) of the present invention, the polymer compound (a1) contained in the polymer emulsion is hydrophobic. The temperature sensitive point of the polymer compound (a1) can be determined as the temperature at which the polymer emulsion starts to become transparent or gel when it is gradually lowered from the temperature range shown (temperature exceeding the temperature sensitive point).
Although the temperature sensitive point of the polymer compound (a1) used in the present invention is not particularly limited, it is preferably 5 to 100 ° C. from the viewpoint of coating workability and film forming property, void forming property, adhesion to a substrate, and the like. 5 to 50 ° C. is more preferable, and 10 to 40 ° C. is most preferable.

The glass transition point of the polymer compound (a1) used in the present invention is not particularly limited, but the glass transition point is −50 to from the viewpoints of film formability and flexibility of the resulting nonaqueous electrolyte secondary battery separator. 150 ° C. is preferable, and −50 to 30 ° C. is more preferable.
The average particle size of the polymer emulsion (A) particles of the present invention is not particularly limited, but is 10 to 200 nm from the viewpoint of the film formability of the coating layer, the porosity and the production efficiency of the polymer emulsion (A). Is more preferable, and more preferably 10 to 100 nm. The average particle size referred to here is the number average particle size of the polymer emulsion (A) measured by the dynamic light scattering method in the temperature range where the polymer compound (a1) exhibits hydrophobicity.

The polymer emulsion (A) of the present invention is formed by a core part composed of particles (a2) and a shell part containing the polymer compound (a1) around the core part. From the viewpoint of the coating film strength of the obtained coating layer, etc., it is preferable. The particles (a2) forming the core part may be organic polymer compounds or inorganic fine particles. From the viewpoint of imparting flexibility to the finally obtained coating film, the organic polymer is used. Compounds are more preferred. The polymer emulsion (A) formed by the core part composed of the particles (a2) and the shell part containing the polymer compound (a1) around the core part is composed of the particles (a2) serving as the core part. It can be produced by synthesizing the above-mentioned polymer compound (a1) after synthesizing by one-step reaction, or after preparing separately prepared particles (a2) to be a core part in the reaction system.
Here, the periphery of the core portion means a peripheral portion of a range that moves in the medium together with the core portion.
In the present invention, the particles (a2) may be any of anionic, cationic, nonionic, and amphoteric.

The ratio (core / shell ratio (mass ratio)) between the core portion composed of the particles (a2) and the shell portion containing the polymer compound (A) around the core portion is not particularly limited. The range of 1/10 to 10/1 is preferable from the viewpoint of the coating strength of the obtained coating layer.
When the particles (a2) are organic polymer compounds, examples thereof include conventionally known poly (meth) acrylates, polyvinyl acetates, acetic acid obtained by radical polymerization, anion polymerization, cationic polymerization, etc. in an aqueous medium. Vinyl-acrylic, ethylene vinyl acetate, silicone, polybutadiene, styrene butadiene, NBR, polyvinyl chloride, chlorinated polypropylene, polyethylene, polystyrene, vinylidene chloride, polystyrene- (meth) acrylate Styrene-maleic anhydride-based copolymers, three-dimensional cross-linked resins, and the like, and silicone-modified acrylic, fluoro-acrylic, acrylic silicon, epoxy-acrylic modified copolymers are also included. The particles (a2) can contain one or more of these. Here, the (meth) acrylate type is simply a methacrylate type (or methacrylate type) or acrylate type. In particular, poly (meth) acrylate-based (acrylic polymer compound) and / or polystyrene- (meth) acrylate-based (styrene-acrylic polymer compound) and silicone polymer compounds are easy to control particle size and physical properties. To preferred.

The particles (a2) in the case of an organic polymer compound are preferably obtained as a polymer emulsion, and can be obtained by using a widely known polymer emulsion production technique. In addition to the method of emulsifying by adding a monomer component to be described later, emulsifying, adding a radical polymerization initiator and carrying out emulsion polymerization by a batch charging reaction, the reaction system can be added to the reaction system by methods such as continuous dripping and divided addition. The method of supplying the said copolymerization component and a radical polymerization initiator to a reaction system is mentioned.
As the monomer for obtaining the particles (a2) in the case of an organic polymer compound, conventionally known monomers exemplified as the submonomer (N) can be used.

  Specific examples of hydrolyzable silyl group-containing compounds that can be used when obtaining a silicone polymer compound as the particles (a2) forming the core of the polymer emulsion (A) of the present invention include tetramethoxysilane and tetraethoxy. Silane, tetra (n-propoxy) silane, tetra (i-propoxy) silane, tetra (n-butoxy) silane, tetra (i-butoxy) silane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, trimethoxy Silane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyl Rimethoxysilane, phenyltriethoxysilane, dimethoxysilane, diethoxysilane, methyldimethoxysilane, methyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane, Bis (triphenoxysilyl) methane, bis (trimethoxysilyl) ethane, bis (triethoxysilyl) ethane, bis (triphenoxysilyl) ethane, 1,3-bis (trimethoxysilyl) propane, 1,3-bis ( Triethoxysilyl) propane, 1,3-bis (triphenoxysilyl) propane, 1,4-bis (trimethoxysilyl) benzene, 1,4-bis (triethoxysilyl) benzene, 3-chloropropyltrimethoxysilane, 3-chloropro Lutriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycid Xylpropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, tetraacetoxysilane, tetrakis (trichloroacetoxy ) Silane, tetrakis (trifluoroacetoxy) silane, triacetoxysilane, tris (trichloroacetoxy) silane, tris (trifluoroacetoxy) silane , Methyltriacetoxysilane, methyltris (trichloroacetoxy) silane, tetrachlorosilane, tetrabromosilane, tetrafluorosilane, trichlorosilane, tribromosilane, trifluorosilane, methyltrichlorosilane, methyltribromosilane, methyltrifluorosilane, tetrakis (Methyl ethyl ketoxime) silane, tris (methyl ethyl ketoxime) silane, methyl tris (methyl ethyl ketoxime) silane, phenyl tris (methyl ethyl ketoxime) silane, bis (methyl ethyl ketoxime) silane, methyl bis (methyl ethyl ketoxime) silane, hexamethyldisilazane, hexamethylcyclo Trisilazane, bis (dimethylamino) dimethylsilane, bis (diethylamino) dimethylsilane, bis (di Tilamino) methylsilane, bis (diethylamino) methylsilane, tetramethoxysilane partially hydrolyzed condensate (trade name “M silicate 51” manufactured by Tama Chemical Industry Co., Ltd., trade name “MSI51” Colcoat Co., Ltd.), trade name “ MS51 "," MS56 "manufactured by Mitsubishi Chemical Corporation), partially hydrolyzed condensate of tetoethoxysilane (trade names" silicate 35 "," silicate 45 ", manufactured by Tama Chemical Industry Co., Ltd., trade names" ESI40 "," ESI48 "manufactured by Colcoat Co., Ltd.), co-hydrolyzed condensate of tetramethoxysilane and tetraethoxysilane (trade name" FR-3 "manufactured by Tama Chemical Industry Co., Ltd., trade name" EMSi48 "manufactured by Colcoat Co., Ltd.) ) And the like. These can be used alone or in combination of two or more.

The glass transition point of the particles (a2) in the case of an organic polymer compound is not particularly limited, but the glass transition point is preferably −50 to 150 ° C., more preferably −50 to 30 ° C. from the viewpoints of film formability and flexibility. Is preferred.
The number average particle diameter of the particles (a2) in the case of an organic polymer compound is not particularly limited, but those having a particle diameter of 3 to 150 nm are preferably used from the viewpoints of film forming properties of the coating layer and production efficiency of the polymer emulsion. 10 to 100 nm is more preferable. The number average particle size referred to here is a number average particle size measured by a dynamic light scattering method.

When the particles (a2) forming the core part are inorganic fine particles, the particles (a2) include, for example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, Zinc oxide, zinc hydroxide, zinc sulfide, zinc carbonate, hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, dry silica, dry alumina, γ-alumina, alumina, colloidal Alumina, pseudoboehmite-based alumina, aluminum hydroxide, zeolite, magnesium hydroxide, metal oxides such as zirconium, titanium, tantalum, niobium, tin, and tungsten, and metal phosphates such as aluminum, vanadium, zirconium, and tungsten And the like, those obtained by replacing a part of the mineral in the other elements and can also be used those obtained by modifying the surface by modifying with an organic material. Among these inorganic fine particles, one type may be used alone, or two or more types may be used.
The particles (a2) forming the core part may be used as primary particles or in a state where secondary particles are formed. In addition, any particle diameter of the particles (a2) forming the core portion can be used, but in order to obtain sufficient coating strength, those having a number average particle diameter of 5 μm or less are preferably used. Preferably those having a thickness of 0.5 μm or less are used, more preferably those having a thickness of 50 nm or less. The lower limit of the particle diameter of the particles (a2) forming the core part is not particularly limited, but is desirably a number average particle diameter of about 3 nm or more from the viewpoint of productivity.

As the reactive functional group contained in the polymer emulsion (A) of the present invention, representative examples include a hydroxyl group, a blocked hydroxyl group, a carboxyl group, a blocked carboxyl group, a carboxylic anhydride group, an amino group, Examples include cyclocarbonate groups, chain carbonate groups, epoxy groups, primary amide bonds, secondary amide bonds, carbamate groups, oxazoline groups, carbonyl groups, acetoacetyl groups, phosphate groups, silanol groups, hydrolyzable silyl groups, and the like. .
The reactive functional group of the polymer emulsion (A) of the present invention can be contained in the polymer compound (a1) and / or the particles (a2) forming the core part. For example, the polymer emulsion (A) containing a reactive functional group is obtained by copolymerizing a main monomer (M) and a submonomer (N) containing a monomer containing a carbonyl group. The main monomer (M) and the submonomer (N) including a monomer containing a carbonyl group can be used alone or in combination of two or more. As for the copolymerization ratio of the main monomer (M) and the submonomer (N) containing the carbonyl group-containing monomer, the hydrophilicity and hydrophobicity of the obtained copolymeric polymer compound change reversibly at the temperature sensitive point. It is determined within a range exhibiting temperature responsiveness.
Although the conventionally well-known monomer illustrated as submonomer (N) can be used as a monomer containing this reactive functional group, Only the typical thing is illustrated.

For example, as the hydroxyl group-containing monomer, various hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate; Various hydroxyl group-containing vinyl ethers such as ethyl vinyl ether or 4-hydroxybutyl vinyl ether; Various hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether; Monoesters of polyoxyalkylene glycols obtained from ether polyols and various unsaturated carboxylic acids such as represented by (meth) acrylic acid; various hydroxyl group-containing monomers as described above And adducts with various lactones, such as represented by ε-caprolactone; or various epoxy group-containing unsaturated monomers, such as represented by glycidyl (meth) acrylate And adducts with various acids, such as represented by acetic acid; and various unsaturated carboxylic acids, such as represented by (meth) acrylic acid, ”(Trade name manufactured by Shell, the Netherlands) and the like, and various hydroxyl group-containing monomers such as adducts with various monoepoxy compounds other than the α-olefin epoxide. Etc. Blocked hydroxyl group-containing monomers include 2-trimethylsiloxyethyl (meth) acrylate, 2-trimethylsiloxypropyl (meth) acrylate, 4-trimethylsiloxybutyl (meth) acrylate, 2-trimethylsiloxyethyl vinyl ether, 4-trimethylsiloxy Silyl ether group-containing vinyl monomers such as butyl vinyl ether as disclosed in JP-A-62-283163; 2- (1-ethoxy) ethoxyethyl (meth) acrylate, 2- (1- Contains acetal or ketal groups such as n-butoxy) ethoxymethyl (meth) acrylate, 2- [2- (meth) acryloyloxy] ethoxytetrahydrofuran, 2,2-dimethyl-4- (meth) acryloyloxymethyldioxolane Vinyl monomers; 3- [2- (meth) acryloyloxy] ethyloxazolidine, 2,2-dimethyl-3- [2- (meth) acryloyloxy] ethyloxazolidine 2-isobutyl-2-methyl-3- And oxazolidine group-containing vinyl monomers such as [2- (meth) acryloyloxy] ethyl oxazolidine.

Examples of the carboxyl group-containing monomer include various unsaturated carboxylic acids such as (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, crotonic acid, itaconic acid, maleic acid or fumaric acid;
Unsaturated dicarboxylic acids and saturated monohydric alcohols such as monomethyl itaconate, mono-n-butyl itaconate, monomethyl maleate, mono-n-butyl maleate, monomethyl fumarate, mono-n-butyl fumarate Monoesters (half esters); monovinyl esters of various saturated dicarboxylic acids, such as monovinyl adipate or monovinyl succinate; various, such as succinic anhydride, glutaric anhydride, phthalic anhydride, or trimellitic anhydride Addition reaction products of the above-mentioned saturated polycarboxylic acid anhydrides with the above-mentioned various hydroxyl group-containing vinyl monomers; and further, the addition of various carboxyl group-containing monomers and lactones as described above Monomers that can be obtained by reaction. Examples of blocked carboxyl group-containing monomers include various silyl ester group-containing vinyl monomers such as trimethylsilyl (meth) acrylate and dimethyl-tert-butylsilyl (meth) acrylate trimethylsilylcrotonate; 1-ethoxyethyl (meth) Monomers having a hemiacetal ester group or a hemiketal ester group such as acrylate, 1-n-butoxyethyl (meth) acrylate, 2-methoxy-2- (meth) acryloyloxypropane 2- (meth) acryloyloxytetrahydrofuran; tert-butyl ester group-containing monomers such as tert-butyl (meth) acrylate and tert-butyl crotonate.
Carboxylic anhydride group-containing monomers include anhydrides of various unsaturated polycarboxylic acids such as maleic anhydride or itaconic anhydride; anhydrides of various unsaturated monocarboxylic acids such as acrylic acid anhydride or methacrylic anhydride Or mixed acid anhydrides of various unsaturated carboxylic acids such as acrylic acid or methacrylic acid and various saturated carboxylic acids such as acetic acid, propionic acid or benzoic acid.

As amino group-containing monomers, 2-dimethylaminoethyl (meth) acrylate, 2-diethylaminoethyl (meth) acrylate, 2-di-n-propylaminoethyl (meth) acrylate, 3-dimethylaminopropyl (meth) acrylate, Various tertiary amino group-containing (meth) acrylic esters such as 4-dimethylaminobutyl (meth) acrylate or N- [2- (meth) acryloyloxy] ethylmorpholine; vinylpyridine, N-vinylcarbazole N- Various tertiary amino group-containing aromatic vinyl monomers such as vinyl quinoline; N- (2-dimethylamino) ethyl (meth) acrylamide, N- (2-diethylamino) ethyl (meth) acrylamide, N- (2-Di-n-propylamino) ethyl (meth) acrylic Various tertiary amino acids such as amide, N- (3-dimethylamino) propyl (meth) acrylamide, N- (4-dimethylamino) butyl (meth) acrylamide or N- [2- (meth) acrylamide] ethylmorpholine Group-containing (meth) acrylamides; N- (2-dimethylamino) ethylcrotonamide, N- (2-diethylamino) ethylcrotonamide, N- (2-di-n-propylamino) ethylcrotonamide, Various tertiary amino group-containing crotonic acid amides such as N- (3-dimethylamino) propyl crotonic acid amide or N- (4-dimethylamino) butyl crotonic acid amide; 2-dimethylaminoethyl vinyl ether, 2-diethylamino Ethyl vinyl ether, 3-dimethylaminopropyl vinyl ether The such as 4-dimethylaminopyridine butyl ether, tertiary amino group-containing vinyl ethers of various or the like.
Examples of cyclocarbonate group-containing monomers include 2,3-carbonate propyl (meth) acrylate, 2-methyl-2,3-carbonate propyl (meth) acrylate, 3,4-carbonate butyl (meth) acrylate, and 3-methyl-3. , 4-carbonate butyl (meth) acrylate, 4-methyl-3,4-carbonate butyl (meth) acrylate, 4,5-carbonate pentyl (meth) acrylate, 6,7-carbonate hexyl (meth) acrylate, 5-ethyl -5,6-carbonate hexyl (meth) acrylate, 7,8-carbonate octyl (meth) acrylate, 2,3-carbonate propyl vinyl ether, di (2,3-carbonate propyl) malate di (2,3-carbonate propyl) itaconate 5-membered cyclocarbonate group-containing vinyl monomers such as [5-N- (meth) acryloylcarbamoyloxy] methyl-5-ethyl-1,3-dioxane-2-one, 5- [N- {2- (meth) acryloyloxy} ethylcarbamoyloxy] methyl-5-ethyl-1,3-dioxan-2-one, 5-ethyl-5- (meth) acryloyloxymethyl-1,3-dioxane 6-membered cyclocarbonate group-containing vinyl monomers such as 2-one and 4- (5-ethyl-2-oxo-1,3-dioxane-5-yl) methoxymethylstyrene.

Epoxy group-containing monomers include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, vinylcyclohexene oxide, glycidyl vinyl ether, methyl glycidyl vinyl ether or allyl glycidyl ether. It is a class.
Monomers containing primary amide bonds and secondary amide bonds include (meth) acrylamide, N-isopropyl (meth) acrylamide, N-methyl (meth) acrylamide, N-vinylformamide, methyl (meth) acrylamide glycolate. , Methyl (meth) acrylamide glycolate methyl ether, N-methylol (meth) acrylamide, Nn-butoxymethyl (meth) acrylamide, addition reaction product of 2-isocyanatoethyl (meth) acrylate and acetylacetone acetoacetate It is like this.

Examples of the monomer containing a carbamate group include methyl N- (meth) acryloylcarbamate, ethyl N- (meth) acryloylcarbamate, N- [2-((meth) acryloyloxy] ethylcarbamate, 2-carbamoyloxy. Ethyl (meth) acrylate, 2- (N-methylcarbamoyloxy) ethyl (meth) acrylate, 2- (N-ethylcarbamoyloxy) ethyl (meth) acrylate, 3-isopropenyl-α, α-dimethylbenzyl isocyanate and 2 -Addition reaction product of hydroxypropyl carbamate, addition reaction product of 2-isocyanatoethyl (meth) acrylate and phenol, addition reaction product of 2-isocyanatoethyl (meth) acrylate and ethanol, 2-isocyanatoethyl ( Meta) Acryle Such as an addition reaction product of benzoate and methyl ethyl ketoxime.

  Examples of the monomer containing a hydrolyzable silyl group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri-n-butoxysilane, vinylmethyldimethoxysilane, vinyltris (β-methoxyethoxy) silane, allyltrimethoxysilane, 2- Trimethoxysilylethyl vinyl ether, 2-triethoxysilylethyl vinyl ether, 2- (methyldimethoxysilyl) ethyl vinyl ether, 3-trimethoxysilylpropyl vinyl ether or 3-triethoxysilylpropyl vinyl ether, 3- (methyldimethoxysilyl) propyl vinyl ether, 3- (meth) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropyltriethoxysilane, 3- (meth) acryloyloxy Propyl methyl dimethoxysilane or 3 (meth) acryloyloxy propyl methyl dichlorosilane, and the like.

The carbonyl group-containing monomer is not particularly limited as long as it has a structure containing a keto group or an aldo group, but acrolein, diacetone acrylamide, diacetone methacrylamide, formyl styrene, vinyl methyl ketone, vinyl ethyl ketone And vinyl isobutyl ketone, acryloxyalkylpropanals, methacryloxyalkylpropanals, diacetone acrylate, diacetone methacrylate, acetonitrile acrylate, 2-hydroxypropyl acrylate acetyl acetate, butanediol acrylate acetyl acetate and the like.
The content of the reactive functional group-containing monomer in the polymer emulsion (A) of the present invention is not particularly limited, but is preferably 0.01 to 50% by mass, more preferably 0.1 to 20% from the viewpoint of coating strength. % By mass.

  As typical examples of the crosslinking agent (C) having a functional group that reacts with the reactive functional group of the polymer emulsion (A) of the present invention, polyisocyanate compound, block polyisocyanate compound, polyepoxy Compound, polycyclocarbonate compound, amino resin, primary or secondary amide bond-containing compound, polycarboxy compound, polyhydroxy compound or compound having both an epoxy group and a hydrolyzable group bonded to a silicon atom in one molecule, Examples thereof include hydrazine compounds having two or more hydrazine groups and / or semicarbazide groups, metal alkoxides, inorganic compounds such as boric acid and borax, and one or more of these can be used in combination.

  Among these, preferred are polyisocyanate compounds, block polyisocyanate compounds, hydrazine compounds having two or more hydrazine groups and / or semicarbazide groups, polyepoxy compounds, polyhydroxy compounds, or epoxy groups and silicon atoms in one molecule. And a metal alkoxide such as tetraalkoxysilane and titanium isopropoxide. More preferable examples include polyisocyanate compound (c2). The polyisocyanate compound (c2) refers to a compound having at least two isocyanate groups in one molecule.

Examples of the polyisocyanate compound (c2) include 1,4-tetramethylene diisocyanate, ethyl (2,6-diisocyanate) hexanoate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2, Aliphatic diisocyanates such as 2,4- or 2,4,4-trimethylhexamethylene diisocyanate; 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 2 Aliphatic triisocyanates such as isocyanate ethyl (2,6-diisocyanato) hexanoate; 1,3- or 1,4-bis (isocyanatomethylcyclohexane), 1,3- or 1,4-diisocyanate Cyclohexane, 3,5,5-trimethyl An alicyclic diisocyanate such as (3-isocyanatomethyl) cyclohexyl isocyanate, dicyclohexylmethane-4,4′-diisocyanate, 2,5- or 2,6-diisocyanatomethylnorbornane; 2,5- or 2, Alicyclic triisocyanates such as 6-diisocyanatomethyl-2-isocyanate propyl norbornane; aralkylene diisocyanates such as m-xylylene diisocyanate, α, α, α′α′-tetramethyl-m-xylylene diisocyanate M- or p-phenylene diisocyanate, tolylene-2,4- or 2,6-diisocyanate, diphenylmethane-4,4′-diisocyanate, naphthalene-1,5-diisocyanate, diphenyl-4,4′-diisocyanate, 4, 4'-diisocyanate Aromatic diisocyanates such as narate-3,3′-dimethyldiphenyl, 3-methyl-diphenylmethane-4,4′-diisocyanate, diphenylether-4,4′-diisocyanate; triphenylmethane triisocyanate, tris (isocyanatophenyl) thio Aromatic triisocyanates such as phosphates, and diisocyanates or polyisocyanates having a uretdione structure obtained by cyclizing and dimerizing the diisocyanates or the isocyanate groups of the triisocyanates; cyclizing the isocyanate groups of the diisocyanates or the triisocyanates; A polyisocyanate having an isocyanurate structure obtained by quantification; reacting the diisocyanate or triisocyanate with water; A polyisocyanate having a burette structure, obtained by reacting the diisocyanate or triisocyanate with carbon dioxide; a polyisocyanate having an oxadiazine trione structure obtained by reacting the diisocyanate or triisocyanate with a polyhydroxy compound, a polycarboxy compound, or a polyamine. The polyisocyanate obtained by making it react with the compound containing active hydrogen like a compound is mentioned, These can be used 1 type or in mixture of 2 or more types.

  Among the polyisocyanate compounds, aliphatic or alicyclic diisocyanates or triisocyanates, aralkylene diisocyanates, or polyisocyanates derived from them are particularly preferable in terms of weather resistance and pot life. Further, as the polyisocyanate, those having a structure such as burette, isocyanurate, urethane, uretdione, and allophanate in the molecule are preferable. Those having a burette structure are excellent in adhesion, those having an isocyanurate structure are excellent in weather resistance, and those having a urethane structure using an alcohol compound having a long side chain are excellent in elasticity and extensibility. In addition, those having a uretdione structure or an allophanate structure are characterized by low viscosity.

  The polyisocyanate compound (c2) used in the present invention has a polyisocyanate compound having two or more isocyanate groups in one molecule and a nonionic and / or ionic hydrophilic group from the viewpoint of water dispersibility. A hydrophilic polyisocyanate composition (c3) obtained by reacting a hydroxyl group-containing hydrophilic compound with an isocyanate group / hydroxyl group equivalent ratio in the range of 1.05 to 1000 is preferred, and an equivalent ratio of 2 to 200 is more preferred. More preferably, it is the range of 4-100. When the equivalence ratio is less than 1.05, the isocyanate group content in the hydrophilic polyisocyanate composition (c3) is remarkably lowered, so that the number of crosslinking points is reduced and the curing rate is not sufficient. If the equivalent ratio exceeds 1000, the coating film flexibility is not necessarily sufficient.

The hydrophilic polyisocyanate composition (c3) can be used without particular limitation as long as it has been introduced with a hydrophilic group by a conventionally known method. For example, a polyisocyanate compound represented by the general formula (5) can be used. , Reaction products of a vinyl polymer having a hydrophilic group and a hydroxyl group and a polyisocyanate compound, an emulsifier and a polyisocyanate obtained by reacting an alkoxypolyalkylene glycol and a dialkanolamine. The reaction product with a compound etc. can be mentioned. Among these, the general formula (1)
^{R 1 O- (R 2 O)} n-H (1)
(Wherein R ¹ represents an alkyl group having 1 to 30 carbon atoms or a group containing two or more aromatic rings, R ² represents an alkylene group having 1 to 5 carbon atoms, and n is an integer of 2 to 250). The reaction product of the polyisocyanate compound shown with the compound shown above, and the reaction product of the vinyl polymer having a hydrophilic group and a hydroxyl group with the polyisocyanate compound are particularly preferred because of their excellent water dispersibility.

  Examples of the general formula (1) include polymethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol monopropyl ether, polyethylene glycol monolauryl ether, poly Alkoxypolyalkylene glycols such as oxyethylene-oxypropylene (random and / or block) glycol monomethyl ether, polyoxyethylene-oxytetramethylene (random and / or block) glycol polybutylene glycol monomethyl ether, (mono ~ Penta) aromatic ring such as styrenated phenyl group, mono (or di, tri) styryl-methyl-phenyl group, tribenzylphenyl group, β-naphthyl group, etc. It can be mentioned nonionic surfactant having a group containing more. Among these, polyethylene glycol monomethyl ether and nonionic surfactants having a (mono-penta) styrenated phenyl group are preferable in terms of self-emulsifying ability and pot life.

As those represented by the general formula (1), those having a molecular weight of preferably from 100 to 10,000, more preferably from 300 to 5,000 can be suitably used.
Examples of the hydrophilic group of the vinyl polymer having a hydrophilic group and a hydroxyl group include various known anionic groups, cationic groups, and nonionic groups, and a nonionic group is preferable. By being a nonionic group, the pot life of the coating composition is remarkably extended, and the particle size of the polyisocyanate oil droplets is reduced, so that the crosslinking efficiency is increased and the coating strength can be further improved.

Specific examples of the vinyl polymer having a hydrophilic group and a hydroxyl group include acrylic polymers, fluoroolefin polymers, vinyl ester polymers, aromatic vinyl polymers, polyolefin polymers, and the like. However, among these, an acrylic polymer is preferable from the viewpoint of compatibility.
The hydrazine derivative (c4) is not particularly limited as long as it is a compound having at least two hydrazine groups and / or semicarbazide groups. Examples of the compound having a hydrazine group include carbohydrazide, isophthalic acid dihydrazide, malonic acid dihydrazide, and succinic acid dihydrazide. Glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, polyacrylic acid hydrazide, ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene- Examples include 1,4-dihydrazine and hydrazine hydrate. Examples of the compound having a semicarbazide group include products obtained by reacting a polyisocyanate compound and the hydrazine compound. As the hydrazine derivative, a compound having a semicarbazide group is preferable from the viewpoint of the strength of the resulting coating film.
The addition amount of the crosslinking agent (C) of the present invention is not particularly limited, but is preferably 0.01 to 10 times the molar amount with respect to each reactive functional group in the obtained polymer emulsion (A). If it is less than 0.01, it cannot be said that the effect of crosslinking is sufficient, and if it exceeds 10 moles, the blending stability is not sufficient.

As an example of producing the polymer emulsion (A) of the present invention, the polymerization reaction is preferably performed in a temperature range exceeding the temperature sensitive point of the polymer compound (a1). Since the polymer compound (a1) exhibits hydrophobicity and forms an emulsion in the temperature region, the polymer emulsion of the present invention can be obtained by using a widely known polymer emulsion production technology in the temperature region. It is done. Specifically, a surfactant is dissolved in water, and the main monomer (M
), Emulsifying by adding a copolymerization monomer component such as a secondary monomer (N), adding a radical polymerization initiator and performing emulsion polymerization by a batch charging reaction, in addition to the reaction system by methods such as continuous dripping and divided addition. The method of supplying the said copolymerization component and a radical polymerization initiator to a reaction system is mentioned.
In producing a polymer emulsion containing the polymer compound (A) used in the present invention, it is preferable to use a surfactant.
The polymer emulsion (A) of the present invention may be any of anionic, cationic, nonionic and amphoteric.

  When the polymer emulsion (A) is anionic, an anionic surfactant and / or a nonionic surfactant is used. For example, fatty acid soap, alkyl sulfonate, alkyl sulfosuccinate, polyoxyethylene alkyl sulfate, polyoxyethylene alkyl aryl sulfate, p-styrene sulfonate, alkyl naphthalene sulfonate, naphthalene sulfonate, formalin heavy Condensates, condensates of higher fatty acids and amino acids, dialkylsulfosuccinic acid ester salts, naphthenic acid salts, alkyl ether carboxylates, acylated peptides, α-olefin sulfonates, N-acylmethyl taurines, alkyl ether sulfates, Anionic surfactants such as secondary higher alcohol ethoxy sulfates, polyoxyethylene alkyl phenyl ether sulfates, monoglycol sulfates, alkyl ether phosphate esters, alkyl phosphate esters, and the like. Examples of the nonionic surfactant include polyoxyethylene alkyl aryl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene sorbitan fatty acid ester, oxyethylene oxypropylene block copolymer, polyglycerin fatty acid ester and the like.

  When the polymer emulsion (A) is cationic, a cationic surfactant and / or a nonionic surfactant is used. For example, examples of the cationic surfactant include laurylamine hydrochloride, alkylbenzyldimethylammonium chloride, lauryltrimethylammonium chloride, alkylammonium hydroxide, polyoxyethylene alkylamine, and the like. Nonionic surfactants include Examples include polyoxyethylene alkyl aryl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene sorbitan fatty acid ester, oxyethylene oxypropylene block copolymer, polyglycerin fatty acid ester and the like.

When the polymer emulsion (A) is nonionic, a nonionic surfactant is used. Examples of the nonionic surfactant include polyoxyethylene alkyl aryl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene sorbitan fatty acid ester, oxyethylene oxypropylene block copolymer, polyglycerin fatty acid ester and the like.
When the polymer emulsion (A) is amphoteric, an amphoteric surfactant can be used. Examples of amphoteric surfactants include carboxybetaine type, aminocarboxylate, and lecithin.
The amount of these surfactants used is preferably 0.05 to 50 parts by mass, more preferably 1 to 30 parts by mass with respect to 100 parts by mass of the solid content of the polymer emulsion (A).

In this invention, the said surfactant can also be used individually by 1 type, and can also use 2 or more types together.
Reducing the amount of non-reactive surfactant by using a “surfactant having a reactive group” during polymerization of the polymer emulsion (A) of the present invention improves the porosity of the resulting coating film. From the viewpoint of making it. The surfactant having a reactive group is generally called a reactive surfactant, and examples thereof include compounds having a hydrophobic group, a hydrophilic group and a reactive group in the molecule.
Examples of the reactive group include carbon-carbon double bonds such as a (meth) allyl group, a 1-propenyl group, a 2-methyl-1-propenyl group, an isopropenyl group, a vinyl group, and a (meth) acryloyl group. The functional group which has is mentioned.

Examples of the anionic reactive surfactant include those having a structure such as a sulfonate group, a sulfate ester base, a carboxylate group, and a phosphate group. As vinyl monomers having a sulfonate group, for example, allyl sulfonic acid 2-methylallylsulfonic acid, vinylsulfonic acid, 4-vinylbenzenesulfonic acid, 2- (meth) acryloyloxyethanesulfonic acid, 3- (meth) acryloyloxypropanesulfonic acid, 2-acrylamido-2-methylpropanesulfone Examples thereof include those obtained by neutralizing various sulfonic acid group-containing vinyl monomers such as acids with various basic compounds. Examples of the basic compound include lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, methylamine, ethylamine, n-butylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, tri-n-butylamine, diethanolamine, 2-dimethyl Aminoethyl alcohol, tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, etc. are mentioned. Examples of the vinyl monomer containing a sulfate ester base include those obtained by neutralizing vinyl monomers containing a sulfate ester group such as sulfate of allyl alcohol with the various basic compounds. Examples of vinyl monomers containing phosphate groups include those obtained by neutralizing phosphate group-containing vinyl monomers such as mono {2- (meth) acryloyloxyethyl} acid phosphate with the various basic compounds. Can be mentioned. Examples of an anionic reactive surfactant containing an allyl group (CH2 = C (-R) -CH2-) (where R is an alkyl group) include, for example, polyoxyethylene allyl glycidyl nonyl phenyl ether sulfate ester salt, etc. Examples of commercially available products include “Adekaria Soap SE-10N” series (trademark: manufactured by Asahi Denka Kogyo Co., Ltd.), “Eleminor JS-2” (trademark: manufactured by Sanyo Chemical Industries, Ltd.), “Latemuru S-180 or S-180A "(trademark: manufactured by Kao Corporation)," H3390A "and" H3390B "(trademark: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). As a reactive surfactant having an anionic property containing a (meth) acryloyl group (CH2═C (—R) —C (═O) —O—) (where R is an alkyl group), for example, as a commercially available product, “Eleminol RS-30” series (trademark: manufactured by Sanyo Chemical Industries, Ltd.), “Antox MS-60” series (trademark: manufactured by Nippon Emulsifier Co., Ltd.), and the like. Examples of the anionic reactive surfactant containing a propenyl group (CH 3 —CH═CH—) include sulfate ammonium salt of polyoxyethylene nonylpropenyl phenyl ether and the like, and “AQUALON HS” is a commercially available product. -10 ”series and“ AQUALON BC ”series (trademark: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

  Examples of the reactive surfactant having a cationic property include cationic vinyl monomers containing a structure having a cationic property such as an amine base. Examples of vinyl monomers having an amine base include neutralizing amino group-containing vinyl monomers such as allylamine, N, N-dimethylallylamine, N, N-diethylallylamine, and N, N-diethylaminopropyl vinyl ether with various acidic compounds. Can be obtained. Examples of the acidic compound include hydrochloric acid, formic acid, acetic acid, lauric acid and the like. Examples of commercially available reactive surfactants having cationic properties include “RF-751” (trademark: manufactured by Nippon Emulsifier Co., Ltd.) and “Blemmer QA” (trademark: manufactured by Nippon Oil & Fats Co., Ltd.).

Examples of the nonionic reactive surfactant include various types such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene higher fatty acid ester, polyoxyethylene-polyoxypropylene block copolymer. Examples thereof include monomers of vinyl ethers, allyl ethers or (meth) acrylic acid esters having a polyether chain in the side chain. Allyl group (CH2 = C (-R) -CH2-) (
However, examples of the nonionic reactive surfactant containing R is an alkyl group include polyoxyethylene allyl glycidyl nonyl phenyl ether, and commercially available products include “ADEKA rear soap NE” series (Asahi Denka Co., Ltd.). Etc.). As a nonionic reactive surfactant containing a (meth) acryloyl group (CH2 = C (-R) -C (= O) -O-) (where R is an alkyl group), commercially available products such as "RMA -560 ”series (manufactured by Nippon Emulsifier Co., Ltd.),“ Blemmer PE ”
Series (made by NOF Corporation) etc. are mentioned. Examples of the nonionic reactive surfactant containing a propenyl group (CH 3 —CH═CH—) include polyoxyethylene nonyl propenyl phenyl ether, and commercially available products include “AQUALON RN series” (first Manufactured by Kogyo Seiyaku Co., Ltd.).
The amount of these reactive surfactants used is preferably 0.05 to 100 parts by mass, more preferably 1 to 50 parts by mass with respect to 100 parts by mass of the solid content of the polymer emulsion (A). .

In the present invention, the reactive surfactant can be used alone, or two or more of the reactive surfactants can be used together. Further, the reactive surfactant is used in combination with the surfactant having no reactivity. You can also
When polymerizing the polymer emulsion (A), polymerization in the presence of polyvinyl alcohol or a polyvinyl alcohol derivative is preferable from the viewpoint of the strength of the finally obtained coating layer.
The polyvinyl alcohol and / or polyvinyl alcohol derivative that can be used in the present invention is not particularly limited, but as polyvinyl alcohol, it is generally called a fully saponified polyvinyl alcohol, which has a saponification degree of 96% to 100%, and is generally a partially saponified polyvinyl. Examples of the alcohol include polyvinyl alcohol having a saponification degree of 76% to 95%, and examples of the polyvinyl alcohol derivative include silanol-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, mercapto group-containing polyvinyl alcohol, and keto group-containing polyvinyl alcohol. One type of polyvinyl alcohol and / or polyvinyl alcohol derivative may be used, or a plurality of types may be mixed and used. The polymerization degree of the polyvinyl alcohol and the polyvinyl alcohol derivative is not particularly limited, but those having a polymerization degree of 300 to 4000 are preferably used. The use ratio of the main monomer (M) and the submonomer (N), polyvinyl alcohol and / or polyvinyl alcohol derivative is determined within a range in which the obtained polymer compound (a1) exhibits temperature responsiveness. The content of the polyvinyl alcohol or polyvinyl alcohol derivative in a1) is not particularly limited within the range of the conditions, but from the viewpoint of the strength of the finally obtained coating film, 0.1 to 50% by mass is preferable. Preferably it is used, More preferably, it is 0.5-20 mass%.

The fine particles (B) used in the coating composition of the present invention may be an organic compound or an inorganic compound.
When the fine particles (B) are organic compounds, for example, conventionally known poly (meth) acrylate-based, polyvinyl acetate-based, vinyl acetate-acrylic-based, which are obtained by radical polymerization, anionic polymerization, cationic polymerization in an aqueous medium, Ethylene vinyl acetate, silicone, polybutadiene, styrene butadiene, NBR, polyvinyl chloride, chlorinated polypropylene, polyethylene, polystyrene, vinylidene chloride, polystyrene- (meth) acrylate, styrene-anhydrous malee Examples include acid-based copolymers, three-dimensional crosslinked resins, and silicone-modified acrylic, fluorine-acrylic, acrylic silicon, and epoxy-acrylic modified copolymers. The above can be contained. Here, the (meth) acrylate type is simply a methacrylate type (or methacrylate type) or acrylate type. In particular, organic polymer compounds classified into poly (meth) acrylates (acrylic polymer compounds) and / or polystyrene- (meth) acrylates (styrene-acrylic polymer compounds) are preferred in terms of void formation. Are preferably used. The fine particles (B) in the case of an organic polymer compound are preferably obtained as a polymer emulsion (A), and can be obtained by using a widely known polymer emulsion production technique. In addition to the method of dissolving the above-mentioned surfactant in a solvent, emulsifying by adding the monomer components described later, adding a radical polymerization initiator and carrying out emulsion polymerization by a batch charging reaction, by continuous dripping, divided addition, etc. The method of supplying the said copolymerization component and radical polymerization initiator to a reaction system to a reaction system is mentioned. As the monomer for obtaining the fine particles (B) in the case of an organic polymer compound, one or more of ethylenically unsaturated monomers exemplified as the submonomer (N) can be used in combination. The glass transition point of the fine particles (B) in the case of an organic polymer compound is not particularly limited, but the glass transition point is preferably 50 ° C. or higher and more preferably 100 ° C. or higher from the viewpoint of void formation.

  When the fine particles (B) are inorganic compounds, for example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc hydroxide, zinc sulfide, carbonate Zinc, hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, dry silica, alumina sol, pseudoboehmite alumina, γ-alumina, aluminum hydroxide, zeolite, magnesium hydroxide, In addition, metal oxides such as zirconium, titanium, tantalum, niobium, tin and tungsten, metal phosphates such as aluminum, vanadium, zirconium and tungsten, International Publication No. 03/066799, International Publication 02/00055 No. porous inorganic particles of the pamphlet, and the like, those obtained by substituting a part of the inorganic compound other elements or may also be used those obtained by modifying the surface by modifying with an organic material. Among these inorganic fine particles, one type may be used alone, or two or more types may be used.

In particular, the fine inorganic particles (B) include oxides of silica, alumina and titanium, and porous inorganic fine particles described in WO 03/066799 and WO 02/000550, which interact with the polymer emulsion (A). From the viewpoints of strength, strength of the coating layer, high porosity, and the like.
The fine particles (B) used in the present invention may be used as primary particles or in a state in which secondary particles are formed. Any particle size of the fine particles (B) can be used, but those having a number average particle size of 10 μm or less are usually used, preferably those having a particle size of 1 μm or less. Furthermore, in order to obtain a high porosity, fine particles (B) having a number average particle size of primary particles of 200 nm or less are preferably used, more preferably those having a number average particle size of 100 nm or less, and more preferably. The thing of 50 nm or less is used.
The lower limit of the particle size of the fine particles (B) is not particularly limited, but a number average particle size of about 3 nm or more is desirable from the viewpoint of the production efficiency of the fine particles (B). The number average particle size referred to here is a number average particle size measured by a dynamic light scattering method.

The fine particles (B) used in the present invention have a solid content ratio of A / B = 1/99 to 90/10, preferably A / B = 1/99 to 50/50, relative to the polymer emulsion (A). A / B = 1/99 to 30/70 is preferable.
The thickness of the coating film obtained here is preferably in the range of 0.1 μm to 20 μm, and more preferably in the range of 0.5 μm to 10 μm. When the non-aqueous electrolyte secondary battery is manufactured if it is too thick, the load characteristics of the battery may be reduced. If it is too thin, a porous film of polyolefin or the like when the battery generates heat due to an accident or the like There is a possibility that the separator shrinks without being able to resist the heat shrinkage.
The temperature sensitive point can be lowered by adding alcohols such as ethyl alcohol to the polymer emulsion of the present invention. That is, when the temperature sensitive point is room temperature or higher, alcohols can be added, and the polymer compound (a1) can be kept in an emulsion state at a temperature near room temperature.
The polymer emulsion containing the polymer compound (a1) is preferable because it can be transported very easily and economically. Alcohols are not particularly limited, but include ethyl alcohol, methyl alcohol, n-propyl alcohol, n-butyl alcohol, isopropyl alcohol, n-pentyl alcohol, n-hexyl alcohol, etc. Ethyl alcohol and isopropyl alcohol are preferably used. These alcohols can also be used independently and can also be used in combination of 2 or more types. In the case of ethanol, the addition amount of the alcohol is usually preferably 5 to 200 parts by mass with respect to 100 parts by mass of water in the polymer emulsion (A).

  In the present invention, the following resins may be mentioned as resins that can be used in combination in order to impart better film formability. For example, polyvinyl alcohol derivatives such as polyvinyl alcohol, cation-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamides, starch and starch derivatives, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, water-soluble resins such as casein and gelatin , Polyvinyl acetates, polyacetals, polyurethanes, polyvinyl butyrals, poly (meth) acrylic acid (esters), polyamides, polyester resins, urea resins, melamine resins, polyacrylonitrile resins, polyalkylene oxide resins, fluoride Examples include vinylidene resin.

Examples of the support used in the present invention include polyolefins, polyesters (for example, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid or esters thereof, ethylene glycol, diethylene glycol, 1,4-butanediol, neo Polyester obtained by polycondensation with a polyhydric alcohol such as pentyl glycol is formed into a film, and usually is subjected to orientation treatment by treatment such as roll stretching, tenter stretching, inflation stretching, etc. Examples include polyethylene terephthalate, polyethylene butylene terephthalate, polyethylene-2,6-naphthalate, and those copolymerized with other components), polyketone, polyimide, cellulose, ceramics and other porous supports. Although it if not particularly limited in the body, but is preferably a polyolefin in view of shutdown of the air gap at high temperatures, the present invention is not limited thereto.
The polyolefin preferably contains a high molecular weight component having a weight average molecular weight of 5 × 10 ⁵ to 15 × 10 ⁶ . Examples of the polyolefin include a high molecular weight homopolymer or copolymer obtained by polymerizing ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and the like. Among these, high molecular weight polyethylene mainly composed of ethylene is preferable.

The porosity of the support is preferably 30 to 80% by volume, more preferably 40 to 70% by volume. If the porosity is less than 30% by volume, the amount of electrolyte retained may be small. If it exceeds 80% by volume, non-porous formation at a high temperature that causes shutdown will be insufficient, that is, when the battery generates heat due to an accident. The current may not be cut off.
The thickness of the support is preferably 5 to 50 μm, more preferably 5 to 30 μm. If the thickness is less than 5 μm, there is a risk that non-porous formation at a high temperature that causes shutdown will be insufficient, and if it exceeds 50 μm, the thickness of the separator for a non-aqueous electrolyte secondary battery becomes thick, so the electric capacity of the battery is small. There is a risk. The pore diameter of the support is preferably 3 μm or less, more preferably 1 μm or less.
In the present invention, it is preferable to perform corona discharge treatment, flame treatment, ultraviolet irradiation treatment, plasma treatment or the like on the surface of the support to be coated.

The coating composition of the present invention is preferably prepared and used at a temperature exceeding the temperature sensitive point of the polymer compound (a1) or the polymer emulsion (A) of the present invention. That is, the coating composition of the present invention has a relatively low viscosity at a temperature exceeding the temperature sensitive point, but the coating composition is rapidly reduced by cooling the coating composition to a temperature below the temperature sensitive point. It thickens (or gels). The thickening occurs when the polymer compound (a1) changes from hydrophobic to hydrophilic. That is, after coating the coating composition of the present invention on the support at a temperature exceeding the temperature sensitive point, the coating composition is formed by a coating solution having a relatively low viscosity by quickly cooling to a temperature below the temperature sensitive point. It is possible to fix the homogeneous coated film as it is by subsequent thickening (or gelation). Furthermore, a good coating state can be maintained even in the drying step. At this time, the emulsion hydrophilized from the particle state forms a coating film while maintaining sufficient voids by strong interaction with the fine particles (B). Further, since the migration of the binder due to the drying of the solvent is suppressed in the drying step, a coating layer having a high strength can be obtained by a strong interaction with the fine particles while forming a coating film having a high porosity while being homogeneous. Moreover, when a highly flexible particle (a2) is used for the core particle (a2) of the polymer emulsion (A), flexibility can be imparted to the coating layer, which is very preferable for forming a battery. .

As means for coating on the support, various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, curtain flow coaters, gate roll coaters, short dwell coaters, extrusion die coaters, size presses, sprays, etc. Various devices can be used on-machine or off-machine.
In forming a plurality of coating layers on a support, simultaneous multilayer coating can be performed. The simultaneous multilayer coating can be performed, for example, by a coating method using an extrusion die coater, a curtain flow coater, or a dip coater.

As means for cooling the coating layer, known means such as a cold air blower, a blower, and a refrigerator can be used. A cold air machine is preferably used, and the temperature of the cold air varies variously depending on the temperature sensitive point of the polymer emulsion of the present invention, preferably a temperature below the temperature sensitive point, more preferably 5 ° C. or more lower than the temperature sensitive point. Further, a temperature lower by 10 ° C. or more than the temperature sensitive point is more preferable.
As means for drying the coating layer, known drying means such as a hot air dryer, a steam heating dryer, a far-infrared dryer and the like can be used. A hot air dryer is preferably used, and examples thereof include a drum dryer, an air cap dryer, an air foil dryer, an air conditioner dryer, and combinations thereof. The drying temperature varies depending on the type of dryer, but the temperature inside the dryer is 50 to 200 ° C, preferably 100 to 150 ° C. When a non-aqueous secondary battery is manufactured using the separator of the present invention, the air permeability of the separator is preferably 50 to 2000 seconds / 100 cc, more preferably 50 to 1000 seconds / 100 cc. When the air permeability is 2000 seconds / 100 cc or more, the load characteristics may be lowered.
Next, the non-aqueous electrolyte secondary battery of the present invention will be described but is not limited thereto.

As the nonaqueous electrolytic solution, for example, a nonaqueous electrolytic solution in which a lithium salt is dissolved in an organic solvent can be used. Lithium salts include LiClO ₄ , LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , Li ₂ B ₁₀ Cl ₁₀ , One or a mixture of two or more of lower aliphatic carboxylic acid lithium salts, LiAlCl _{4 and the} like can be mentioned. The lithium salt is selected from the group consisting of LiPF ₆ containing fluorine, LiAsF ₆ , LiSbF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , and LiC (CF ₃ SO ₂ ) ₃ among these. It is preferable to use those containing at least one selected from the above.

Examples of the non-aqueous electrolyte include propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 4-trifluoromethyl-1,3-dioxolan-2-one, 1,2-di (methoxycarbonyloxy) Carbonates such as ethane; ethers such as 1,2-dimethoxyethane, 1,3-dimethoxypropane, pentafluoropropyl methyl ether, 2,2,3,3-tetrafluoropropyl difluoromethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran Esters such as methyl formate, methyl acetate and Y-butyrolactone; nitriles such as acetonitrile and butyronitrile; amides such as N, N-dimethylformamide and N, N-dimethylacetamide Carbamates such as 3-methyl-2-oxazolidone; sulfur-containing compounds such as sulfolane, dimethyl sulfoxide, and 1,3-propane sultone, or those obtained by introducing a fluorine group into the above-mentioned substances can be used. Two or more of these are mixed and used.

Among these, those containing carbonates are preferred, and cyclic carbonates and acyclic carbonates, or mixtures of cyclic carbonates and ethers are more preferred. As a mixture of cyclic carbonate and acyclic carbonate, ethylene carbonate and dimethyl have a wide operating temperature range and are hardly decomposable even when a graphite material such as natural graphite or artificial graphite is used as the negative electrode active material. A mixture comprising carbonate and ethyl methyl carbonate is preferred.
As the positive electrode sheet, a sheet in which a mixture containing a positive electrode active material, a conductive material, and a binder is supported on a current collector is usually used. Specifically, as the positive electrode active material, a material containing a material that can be doped / undoped with lithium ions, a carbonaceous material as a conductive material, and a thermoplastic resin as a binder can be used. Examples of the material that can be doped / undoped with lithium ions include lithium composite oxides containing at least one transition metal such as V, Mn, Fe, Co, and Ni. Among these, lithium composite oxides having an α-NaFeO ₂ type structure such as lithium nickelate and lithium cobaltate, and lithium composite oxides having a spinel type structure such as lithium manganese spinel are preferable in that the average discharge potential is high. Can be mentioned.

As the binder, polyvinylidene fluoride, vinylidene fluoride copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, Examples include ethylene-tetrafluoroethylene copolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymers, thermoplastic resins such as thermoplastic polyimide, polyethylene, and polypropylene, and the polymer emulsion (A) of the present invention. Can be mentioned.
Examples of the conductive agent include carbonaceous materials such as natural graphite, artificial graphite, cokes, and carbon black. As the conductive material, each may be used alone, for example, artificial graphite and carbon black may be mixed and used.

  As the negative electrode sheet, for example, a material capable of doping and dedoping lithium ions, lithium metal, or a lithium alloy can be used. Materials that can be doped / undoped with lithium ions include carbonaceous materials such as natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fibers, and fired organic polymer compounds, and lower potential than the positive electrode. And chalcogen compounds such as oxides and sulfides for doping and dedoping lithium ions. As a carbonaceous material, a carbonaceous material mainly composed of graphite materials such as natural graphite and artificial graphite, because it has a high potential flatness and a low average discharge potential, so that a large energy density can be obtained when combined with a positive electrode. Is preferred.

As the negative electrode current collector, Cu, Ni, stainless steel, or the like can be used. In particular, in a lithium secondary battery, Cu is preferable because it is difficult to form an alloy with lithium and it can be easily processed into a thin film. As a method of supporting the mixture containing the negative electrode active material on the negative electrode current collector, a method of pressure molding, or a method of pasting into a paste using a solvent or the like and applying pressure to the current collector by pressing after drying Is mentioned.
The shape of the battery of the present invention is not particularly limited, and may be any of a paper type, a coin type, a cylindrical type, a rectangular shape, and the like.
Non-aqueous electrolysis obtained using a non-aqueous electrolyte secondary battery separator, wherein one or more coating layers comprising the non-aqueous electrolyte secondary battery coating composition of the present invention are laminated. Since the liquid secondary battery has good dimensional stability at high temperatures, contact between the positive electrode and the negative electrode due to shrinkage of the separator is avoided, and a highly safe non-aqueous electrolyte secondary battery is obtained.

The following examples, reference examples and comparative examples will specifically explain the present invention, but these do not limit the scope of the present invention. In the examples, parts and% mean parts by mass and% by mass, respectively, unless otherwise specified.
In Examples and Reference Examples, the physical properties of the non-aqueous electrolyte secondary battery coating composition and the non-aqueous electrolyte secondary battery separator were measured by the following methods.
(1) Number average particle size: measured using Nikkiso Microtrac UPA-9230.
(2) Temperature sensitive point: When the temperature of the polymer emulsion, in which the concentration of the polymer emulsion (A) is adjusted to 5% by mass with an aqueous solvent while maintaining the temperature above the polymerization temperature, is gradually reduced. The temperature was determined by measuring the temperature at which the liquid became transparent or gelled.
(3) Film thickness: compliant with JIS K7130.

(4) Porosity: The porosity was measured from the mercury intrusion amount and the film thickness obtained using a mercury porosimeter ("Autopore 9500" manufactured by Shimadzu Corporation).
Porosity (%) = mercury intrusion amount (μl) / coating film thickness (μm) × 100
(5) Cut the dimension retention film into a 15 cm square, write a 10 cm square square ruled line at the center, and sandwich between two 0.5 mm thick aluminum plates coated with a release agent, and 60 ° C. In a heated oven. The temperature of the oven was raised to 150 ° C. at a rate of 1 ° C./minute and held for 10 minutes, then taken out, the square dimensions were measured, and the dimension retention rate was calculated. The calculation method of the dimensional retention rate is as follows.
Ruled line length in MD direction before heating: L1
Ruled line length in TD direction before heating: W1
Ruled line length in MD direction after heating: L2
Ruled line length in TD direction after heating: W2
Dimension retention (%) = ((L2 × W2) / (L1 × W1)) × 100

(6) Evaluation as a separator for nonaqueous electrolyte batteries Commercially available needle coke (KOA-SJCoke manufactured by Koa Oil Co., Ltd.) was pulverized to an average particle size of 10 μm. 10 parts by weight of styrene / butadiene latex prepared in the composition shown in Table 1 with respect to 100 parts by weight of this pulverized product (solid content 50% by weight), 100 parts by weight of aqueous carboxymethylcellulose solution (solid content 1% by weight) as a thickener, 1 part by weight of 1/10 normal ammonia water was added and mixed to obtain a coating solution. Using a 10 μm thick Ni foil as a base material, this coating solution was applied and dried at 160 g / m ² to obtain a negative electrode having a thickness of 150 μm.
Meanwhile _{Li 1.03 Co 0.95 Sn 0.042 O 2} 100 parts by weight of graphite powder 7.5 parts by weight of the average particle diameter of 2 [mu] m, acetylene black 2.5 parts by weight of the fluororubber of methyl isobutyl ketone solution (concentration: 4 wt%) Of 50 parts by weight was mixed and stirred to obtain a coating solution. This coating solution was applied and dried at 290 g / m ^{2 using a} commercially available Al foil (thickness: 15 μm) as a base material to obtain a positive electrode having a thickness of 110 μm.

The positive electrode and the negative electrode were cut into 1 cm × 5 cm, the negative electrode, each of the separators of Examples 1 and 2 and Comparative Examples 1 and 2, and the positive electrode were stacked in this order to assemble the battery, and an electrolyte (1 mol / l lithium borofluoride) was added to the separator. The solution (solvent: propylene carbonate / ethylene carbonate / γ-butyllactone = 1/1/2) was sufficiently impregnated. Next, the discharge capacity (discharge current 1.5 mA) is measured when the battery is charged to 4.2 V with a charge current of 1.5 mA and discharged to 3.0 V with a discharge current of 1.5 mA to obtain a discharge capacity DA. When the battery is charged under the above conditions and the discharge capacity (discharge current 30.0 mA) is measured, this is defined as the discharge capacity DB. The load characteristics of the battery are obtained by the following formula.
Load characteristics (%) = (DB / DA) × 100
(7) Safety test: A nail penetration test (Battery Industry Association Guideline SBAG1101-1997) is performed in an overcharged state of 4.3 V, and the temperature rise of the battery subjected to the test is observed. The evaluation was as follows.
○: No temperature rise. Δ: Temperature rise below 30 ° C. X: Temperature rise of 30 ° C. or more.

[Reference Example 1]
A reaction vessel equipped with a stirrer, a reflux condenser, a dropping tank and a thermometer was charged with 212 parts of water and 1 part of a 25% aqueous solution of “ADEKA rear soap SE1025N”, and the inside of the reaction vessel was brought to 80 ° C. Next, 2 parts of acrylic acid, 2 parts of diacetone acrylamide, 51 parts of methyl methacrylate, 5 parts of butyl acrylate, and 1 part of 2-hydroxyethyl methacrylate were mixed, and this monomer mixture was mixed with “Adekari Soap SE1025N”. A mixture of 10 parts of a 25% aqueous solution and 10 parts of a 2% aqueous solution of ammonium persulfate was made into a pre-emulsion liquid by a homogenizer and added into the reaction vessel from a dropping tank over 2 hours. The temperature in the reaction vessel was kept at 80 ° C. during the addition and for another hour after the addition was completed. The number average particle size of the emulsion at this stage was 10 nm. Subsequently, 10 parts of a 2% aqueous solution of ammonium persulfate, 140 parts of N-isopropylacrylamide and 600 parts of water began to be added into the reaction vessel from the dropping tank, and the addition was completed over 2.5 hours. The liquid temperature in the reaction vessel was kept at 80 ° C. during the addition and for 1 hour after the completion of the addition, and then cooled to 50 ° C., and 780 parts of a 60% ethanol aqueous solution was gradually added into the reaction vessel. After completion of the addition of the ethanol aqueous solution, the mixture was cooled to room temperature to obtain a binder (I) in which an emulsion having a resin solid content of 11.2% and a number average particle size of 100 nm was formed. The temperature point was measured and found to be 31 ° C.

[Reference Example 2]
A reaction vessel equipped with a stirrer, a reflux condenser, a dropping tank and a thermometer was charged with 212 parts of water and 1 part of a 25% aqueous solution of “ADEKA rear soap SE1025N”, and the inside of the reaction vessel was brought to 80 ° C. Next, 2 parts of acrylic acid, 2 parts of diacetone acrylamide, 51 parts of methyl methacrylate, 5 parts of butyl acrylate, and 1 part of 2-hydroxyethyl methacrylate were mixed, and this monomer mixture was mixed with “Adekari Soap SE1025N”. A mixture of 10 parts of a 25% aqueous solution and 10 parts of a 2% aqueous solution of ammonium persulfate was made into a pre-emulsion liquid by a homogenizer and added into the reaction vessel from a dropping tank over 2 hours. The temperature in the reaction vessel was kept at 80 ° C. during the addition and for another hour after the addition was completed. The number average particle size of the emulsion at this stage was 10 nm. Subsequently, a mixture of 10 parts of a 2% aqueous solution of ammonium persulfate, 105 parts of N-isopropylacrylamide, 35 parts of 2-hydroxyethyl methacrylate, and 600 parts of water was started to be added into the reaction vessel from the dropping tank, and 2.5 hours The addition was completed over time. The liquid temperature in the reaction vessel was kept at 80 ° C. during the addition and for 1 hour after the completion of the addition, and then cooled to 50 ° C., and 780 parts of a 60% ethanol aqueous solution was gradually added into the reaction vessel. After completion of the addition of the aqueous ethanol solution, the mixture was cooled to room temperature to obtain a binder (b) in which an emulsion having a resin solid content of 11.2% and a number average particle size of 100 nm was formed. The temperature point was measured and found to be 26 ° C.

[Reference Example 3]
In a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer, 100 parts of benzene, 10 parts of N-isopropylacrylamide, 1 part of diacetone acrylamide, 2,2′-azobis (2-methylpropionamidine) 2 1 part of 5% aqueous solution of basic acid salt and 0.1 part of 70% aqueous solution of N, N-dimethylaminopropylacrylamide methyl chloride quaternary salt were mixed and purged with nitrogen at room temperature, then reacted at 50 ° C. for 8 hours. The benzene was evaporated by reducing the pressure. The obtained reaction product was dissolved in acetone, and then poured into a large amount of n-hexane to collect a precipitate. The precipitate was decompressed to remove acetone and n-hexane, and then dissolved in water at 20 ° C. so that the solid content concentration was 10% to obtain a binder (c). The temperature point was measured and found to be 31 ° C.

[Reference Example 4]
Into a reaction vessel equipped with a stirrer, a reflux condenser, a dropping tank and a thermometer, 650 parts of water was added to bring the inside of the reaction vessel to 80 ° C. Next, 7 parts of a 25% aqueous solution of “ADEKA rear soap SE1025N” and 14 parts of a 2% aqueous solution of ammonium persulfate were added. Five minutes later, 360 parts of methyl methacrylate, 540 parts of butyl acrylate, 18 parts of methacrylic acid, 40 parts of 25% aqueous solution of “ADEKA rear soap SE1025N”, 45 parts of 2% aqueous solution of ammonium persulfate and 450 parts of water were obtained by a homogenizer. The pre-emulsified liquid was added to the reaction vessel and the addition was completed over 4 hours. The liquid temperature in the reaction vessel was kept at 80 ° C. during the addition and for 1 hour after the completion of the addition, and then cooled to room temperature. A binder (d) in which an emulsion having a resin solid content of 43% and a number average particle diameter of 100 nm was formed was obtained. Attempts were made to measure the temperature sensitive point, but no change that was judged to be a temperature sensitive point occurred.

[Reference Example 5]
<Synthesis example of polysemicarbazide compound crosslinking agent (PSC)>
168 parts of hexamethylene diisocyanate and 1.5 parts of water as a burette agent are dissolved in 130 parts of a 1: 1 (mass ratio) mixed solvent of ethylene glycol methyl ether acetate and trimethyl phosphate, and the reaction temperature is 160 ° C. The reaction was carried out for 1 hour. Using the thin film distillation can, the obtained reaction liquid was subjected to a second process under the condition of 133 Pa / 160 ° C. for the first time and 13.3 Pa / 200 ° C. for the second time, and excess hexamethylene diisocyanate. The solvent was removed by distillation to obtain a residue. The resulting residue contained 99.9% by weight of polyisocyanate (a hexamethylene diisocyanate burette type polyisocyanate) and 0.1% by weight of residual hexamethylene diisocyanate. The viscosity of the obtained residue was 1900 (± 200) mPa.s. The number average molecular weight was s / 25 ° C., the number average molecular weight was about 600 (± 100), the average number of —NCO functional groups was about 3.3, and the content of —NCO groups was 23.3 mass%.

  To a reactor having a reflux condenser, a thermometer and a stirrer, 80 parts of hydrazine monohydrate was added to 1000 parts of isopropyl alcohol with stirring at room temperature over about 30 minutes, and then the polyisocyanate (NCO group content 23. (3% by mass) A solution of 144 parts dissolved in 576 parts of tetrahydrofuran was added at 10 ° C. over about 1 hour, and further stirred at 40 ° C. for 3 hours, and 1000 parts of water was added. Subsequently, isopropyl alcohol, hydrazine, tetrahydrofuran, water and the like in the obtained reaction solution were distilled off under heating and reduced pressure to obtain 168 parts of a polysemicarbazide compound (PSC) having a biuret structure. When the average number of semicarbazide residues was measured, it was 4.6 meq / g.

[Reference Example 6]
<Synthesis example of polyisocyanate crosslinking agent (PI)>
Methoxypolyethylene glycol (MPG-130, ethylene oxide repeating unit = 9.4, manufactured by Nippon Emulsifier Co., Ltd.) and ammonium alkylbenzenesulfonate (New Coal 210, solid content 50%, manufactured by Nippon Emulsifier Co., Ltd.) The mixture was mixed at a weight ratio of 5: 2, and water and the solvent were removed by vacuum distillation. 1000 g of isocyanurate type polyisocyanate (Duranate TPA-100, manufactured by Asahi Kasei Chemicals Co., Ltd.) and 700 g of the mixture of methoxypolyethylene glycol and ammonium alkylbenzenesulfonate obtained above were mixed and subjected to urethanization reaction at 120 ° C. for 2 hours. . The obtained hydrophilic polyisocyanate composition was a pale yellow liquid, the isocyanate group content was 10.8%, and the viscosity was 9500 mPa · s. 10 parts of propylene glycol monomethyl ether acetate was added to the hydrophilic polyisocyanate composition with stirring to obtain a polyisocyanate crosslinking agent (PI).

[Example 1]
Silica-coated titanium oxide hydrosol (trade name “MPT-422”, manufactured by Ishihara Sangyo Co., Ltd., solid content 19.3%, number average particle diameter 9.1 nm) was diluted to 10% with purified water, The dispersion was sufficiently dispersed with a disperser, the dispersion was heated to 60 ° C., and the binder (a) obtained in Reference Example 1 was added to the titanium oxide / binder (a) = 100/10 (solid content mass ratio). After adding and mixing at a ratio, the PSC of Reference Example 5 was mixed at 60 ° C. at a ratio of PSC / binder (ii) = 2/100 (solid content mass ratio) to the non-aqueous electrolyte secondary solution. A battery coating composition was prepared.
A coating composition is applied on a support (porous polyethylene film: basis weight 15 g / m ² , thickness 25 μm), immediately after applying 10 ° C. cold air for 1 minute, then applying 60 ° C. hot air for 5 minutes, A separator for a nonaqueous electrolyte secondary battery having a coating layer thickness of 28 μm and a coating amount of 3 g / m ² was obtained. The porosity of the coating layer was 80% when measured with a mercury porosimeter after the coating layer was similarly formed using a non-porous support. The separator has a dimensional retention of 86%, a load characteristic of 41%, and there is no problem in the safety test (O).

[Example 2]
Silica-coated titanium oxide hydrosol (trade name “MPT-422”, manufactured by Ishihara Sangyo Co., Ltd., solid content 19.3%, number average particle diameter 9.1 nm) was diluted to 10% with purified water, The dispersion was sufficiently dispersed with a disperser, the dispersion was heated to 60 ° C., and the binder (b) obtained in Reference Example 2 was replaced with titanium oxide / binder (b) = 100/10 (solid content mass ratio). After adding and mixing at a ratio, PI of Reference Example 6 was mixed at 60 ° C. at a ratio of PI / binder (b) = 2/100 (solid content mass ratio), and a non-aqueous electrolyte secondary solution A battery coating composition was prepared.
A coating composition is applied on a support (porous polyethylene film: basis weight 15 g / m ² , thickness 25 μm), immediately after applying 10 ° C. cold air for 1 minute, then applying 60 ° C. hot air for 5 minutes, A separator for a nonaqueous electrolyte secondary battery having a coating layer thickness of 28 μm and a coating amount of 3 g / m ² was obtained. The porosity of the coating layer was 78% as measured by a mercury porosimeter after the coating layer was similarly formed using a non-porous support. The dimensional retention rate of the separator is 90%, the load characteristic is 45%, and the safety test has no problem (O).

[Comparative Example 1]
Silica-coated titanium oxide hydrosol (trade name “MPT-422”, manufactured by Ishihara Sangyo Co., Ltd., solid content 19.3%, number average particle diameter 9.1 nm) was diluted to 10% with purified water, The dispersion was sufficiently dispersed with a disperser, the dispersion was heated to 60 ° C., and the binder (c) obtained in Reference Examples 3 and 4 was replaced with titanium oxide / binder (c) / binder (d) = 100. A coating composition for a non-aqueous electrolyte secondary battery was prepared by adding and mixing at a ratio of / 3/12 (solid content mass ratio).
A coating composition is applied on a support (porous polyethylene film: basis weight 15 g / m ² , thickness 25 μm), immediately after applying 10 ° C. cold air for 1 minute, then applying 60 ° C. hot air for 5 minutes, A separator for a nonaqueous electrolyte secondary battery having a coating layer thickness of 28 μm and a coating amount of 3 g / m ² was obtained. The porosity of the coating layer was 80% when measured with a mercury porosimeter after the coating layer was similarly formed using a non-porous support. The separator had a dimensional retention of 86%, a load characteristic of 43%, and a slight increase in temperature after the safety test (Δ).

[Comparative Example 2]
Silica-coated titanium oxide hydrosol (trade name “MPT-422”, manufactured by Ishihara Sangyo Co., Ltd., solid content 19.3%, number average particle diameter 9.1 nm) was diluted to 10% with purified water, The dispersion was sufficiently dispersed with a disperser, the dispersion was heated to 60 ° C., and the binder (d) obtained in Reference Example 4 was replaced with titanium oxide / binder (d) = 100/10 (solid content mass ratio). A nonaqueous electrolyte secondary battery coating composition was prepared by adding and mixing at the above ratio.
A coating composition is applied on a support (porous polyethylene film: basis weight 15 g / m ² , thickness 25 μm), immediately after applying 10 ° C. cold air for 1 minute, then applying 60 ° C. hot air for 5 minutes, A separator for a nonaqueous electrolyte secondary battery having a coating layer thickness of 28 μm and a coating amount of 3 g / m ² was obtained. The porosity of the coating layer was 78% as measured by a mercury porosimeter after the coating layer was similarly formed using a non-porous support. The separator had a dimensional retention rate of 60%, a load characteristic of 40%, and a significant increase in temperature was observed in the safety test (×).

The coating composition for a non-aqueous electrolyte secondary battery provided by the present invention is useful because it can provide a non-aqueous electrolyte secondary battery having high porosity, high strength and excellent reliability at high temperatures. It is.

Claims (6)

  Polymer emulsion (A) and fine particles (B) containing a polymer compound (a1) exhibiting hydrophilicity in a temperature range below a certain temperature (temperature sensitive point) and hydrophobic in a temperature range exceeding the temperature sensitive point A coating composition for a non-aqueous electrolyte secondary battery, comprising:   The polymer emulsion (A) is a hydroxyl group, a blocked hydroxyl group, a carbonyl group, a carboxyl group, a blocked carboxyl group, a carboxylic anhydride group, an amino group, a cyclocarbonate group, an epoxy group, a hydrolyzable silyl group, a silanol. The non-crosslinking agent (C) according to claim 1, which contains at least one reactive functional group selected from the group consisting of a group and has a cross-linking agent (C) having a functional group that reacts with the reactive functional group. A coating composition for a water electrolyte secondary battery.   The coating composition for a nonaqueous electrolyte secondary battery according to claim 1 or 2, wherein the polymer emulsion (A) is obtained by polymerization in the presence of polyvinyl alcohol and / or a polyvinyl alcohol derivative. .   A non-aqueous electrolyte secondary battery coating composition according to any one of claims 1 to 3 is laminated at least one layer on at least one surface of a support. Separator for water electrolyte secondary battery.   The separator for a nonaqueous electrolyte secondary battery according to claim 4, wherein the support is a polyolefin porous film.   A nonaqueous electrolyte secondary battery using the separator for a nonaqueous electrolyte secondary battery according to claim 4.