Resin composition for non-aqueous secondary battery separator, slurry composition, non-aqueous secondary battery separator, and non-aqueous secondary battery

Abstract

To provide a resin composition for a non-aqueous secondary battery separator that has good storage stability of a slurry composition for a non-aqueous secondary battery separator, and in which a separator exhibits excellent heat resistance, adhesion and scratch resistance, and a non-aqueous secondary battery is excellent in battery characteristics.SOLUTION: A resin composition for a non-aqueous secondary battery separator contains an aqueous medium and a polymer (A), wherein the polymer (A) is a polymer of an ethylenically unsaturated monomer (a) mixture containing 40.0 to 99.8 mass% of an ethylenically unsaturated monomer (a-1) having an amide group, and 0.2 to 60.0 mass% of an ethylenically unsaturated monomer (a-2) having at least one functional group selected from the group consisting of an alkyl group having 8 or more carbon atoms, a styrenated phenyl group and an alkylene oxide group having 3 or more carbon atoms, and a hydrophilic group in one molecule, based on the total mass of the ethylenically unsaturated monomer (a).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition for a non-aqueous secondary battery separator that can be used to form a protective layer for a separator of a non-aqueous secondary battery such as a lithium-ion secondary battery. The present invention also relates to a slurry composition containing the resin composition for a non-aqueous secondary battery separator, a separator having a protective layer formed from the slurry composition, and a non-aqueous secondary battery having the separator. [Background technology]

[0002] Non-aqueous secondary batteries are used in a wide range of applications due to their compact size, lightweight design, high energy density, and ability to be repeatedly charged and discharged. Lithium-ion secondary batteries, in particular, are capable of producing high power output and are therefore widely used in a wide range of applications, including smartphones, tablets, laptops, and electric vehicles, and demand for these batteries is rapidly growing. Lithium-ion secondary batteries have an electrically insulating separator between the electrodes to ensure safety in the event of an abnormality. This separator has a porous structure that allows lithium ions to pass between them under normal conditions. However, when an abnormal reaction occurs and the temperature rises, the pores become blocked, blocking the passage of lithium ions and preventing battery short circuits. These separators include porous polyolefin sheets such as polyethylene and polypropylene, as well as coated sheets based on these substrates and further coated with a slurry composition containing non-conductive fine particles and a binder to provide heat resistance. In recent years, thinner separators are being demanded as batteries become increasingly high-capacity, and the substrate thickness of these coated separators has also been reduced.

[0003] On the other hand, thinning the substrate tends to further reduce the heat resistance and durability of the separator. Therefore, in recent years, studies have been conducted to impart excellent heat resistance and durability to such separators. Patent Document 1 discloses a resin composition for a non-aqueous secondary battery separator that uses a water-soluble resin mainly composed of structural units derived from an ethylenically unsaturated monomer having an amide group, and Patent Document 2 discloses a resin composition for a non-aqueous secondary battery separator that includes a water-soluble resin obtained by copolymerizing an ethylenically unsaturated monomer having an amide group, an ethylenically unsaturated monomer having a carboxy group, and an ethylenically unsaturated monomer having a hydroxy group. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 026095 [Patent Document 2] International Publication No. 2021 / 020061 Summary of the Invention [Problem to be solved by the invention]

[0005] These resin compositions for non-aqueous secondary battery separators have excellent heat resistance and good binding properties with inorganic fine particles, and therefore have the effect of suppressing thermal shrinkage of the separator. However, conventional slurry compositions have poor storage stability and tend to aggregate, especially when stored at high temperatures. Therefore, separators made from slurry compositions stored at high temperatures tend to exhibit poor heat resistance, adhesion, and coating resistance, and battery performance is also likely to deteriorate. Storage stability at high temperatures is directly related to the storage and reuse of slurry compositions in summer, the feasibility of transporting them to hot regions, and other factors, and is therefore an issue that directly affects the efficiency and cost reduction of secondary battery production.

[0006] In view of the above, there is a need for a resin composition for a non-aqueous secondary battery separator that has good storage stability and allows the slurry composition to exhibit good performance even after storage under high temperature conditions.

[0007] The present invention aims to provide a resin composition for a non-aqueous secondary battery separator, which has good storage stability, and in which a non-aqueous secondary battery separator formed from the slurry composition exhibits excellent heat resistance, adhesion, and durability not only initially but also after long-term storage at high temperatures, and further in which a non-aqueous secondary battery using the separator exhibits excellent battery characteristics (rate characteristics and high-temperature cycle characteristics). [Means for solving the problem]

[0008] That is, the present invention relates to a resin composition for a non-aqueous secondary battery separator, comprising a polymer (A1) and an aqueous medium, wherein the polymer (A1) is a polymer of an ethylenically unsaturated monomer mixture containing 40.0 to 99.8 mass% of an ethylenically unsaturated monomer (a-1) having an amide group, and 0.2 to 60.0 mass% of an ethylenically unsaturated monomer (a-2) having a hydrophilic group and at least one functional group selected from the group consisting of an alkyl group having 8 or more carbon atoms, a styrenated phenyl group, and an alkylene oxide group having 3 or more carbon atoms, based on the total mass of the ethylenically unsaturated monomer mixture. [Effects of the Invention]

[0009] The present invention can form a separator with excellent heat resistance, adhesion, and abrasion resistance, and can provide a nonaqueous secondary battery using the same with excellent battery characteristics (rate characteristics and high-temperature cycle characteristics). Furthermore, the resin composition and slurry composition for a nonaqueous secondary battery separator of the present invention have excellent storage stability, so that aggregation of polymers and inorganic particles can be suppressed even when stored for long periods under high-temperature conditions. Because of this excellent storage stability and redispersibility, even when the slurry composition is re-stirred after storage and applied to a substrate, a thin, uniform protective layer can be formed, thereby providing a separator that can exhibit excellent heat resistance, adhesion, and abrasion resistance, and a nonaqueous secondary battery using the same with excellent battery characteristics. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the binder dispersion for a non-aqueous secondary battery separator, the slurry composition for a non-aqueous secondary battery separator, the non-aqueous secondary battery separator, and the non-aqueous secondary battery of the present invention will be described based on preferred embodiments. However, the present invention is not limited to this. Each component can be replaced with any component that can perform the same function, or any component can be added. In addition, in this specification, a numerical range specified using "to" includes the numerical values ​​before and after "to" as the lower and upper limit values ​​of the range. In addition, in this specification, "film" and "sheet" are not distinguished by thickness. Furthermore, in this specification, unless otherwise specified, the terms "(meth)acrylamide," "(meth)acrylate," and "(meth)acrylic acid" mean "acrylamide or methacrylamide," "acrylate or methacrylate," and "acrylic acid or methacrylic acid," respectively.

[0011] In this specification, the ethylenically unsaturated monomer (a-1) having an amide group, the ethylenically unsaturated monomer (a-2) having in one molecule at least one functional group selected from the group consisting of an alkyl group having 8 or more carbon atoms, a styrenated phenyl group, and an alkylene oxide group having 3 or more carbon atoms, and a hydrophilic group, the ethylenically unsaturated monomer (a-1), the ethylenically unsaturated monomer (a-2), the other ethylenically unsaturated monomer (a-3) copolymerizable with the ethylenically unsaturated monomer (a-2), and the other polymer (A2) may be abbreviated as the ethylenically unsaturated monomer (a-1), the ethylenically unsaturated monomer (a-2), the ethylenically unsaturated monomer (a-3), and the polymer (A2), respectively. Unless otherwise noted, the various components appearing in this specification may be used independently either alone or in combination of two or more.

[0012] <Resin composition for non-aqueous secondary battery separator> The resin composition for a non-aqueous secondary battery separator of the present invention is used to form a protective film for a separator provided between a positive electrode and a negative electrode in a non-aqueous secondary battery, and can be suitably used as a slurry composition for a non-aqueous secondary battery separator that is directly applied to a substrate such as a porous olefin substrate or to an electrode.

[0013] The resin composition for a non-aqueous secondary battery separator of the present invention comprises a polymer (A1) and an aqueous medium, wherein the polymer (A1) is a polymer of an ethylenically unsaturated monomer mixture containing 40.0 to 99.8 mass% of an ethylenically unsaturated monomer (a-1) having an amide group, and 0.2 to 60.0 mass% of an ethylenically unsaturated monomer (a-2) having a hydrophilic group and at least one functional group selected from the group consisting of an alkyl group having 8 or more carbon atoms, a styrenated phenyl group, and an alkylene oxide group having 3 or more carbon atoms, based on the total mass of the ethylenically unsaturated monomer mixture. This improves the storage stability of the slurry composition for non-aqueous secondary battery separators, so that separators formed from the slurry composition exhibit excellent heat resistance, adhesion, and corrosion resistance even after long-term storage at high temperatures.Furthermore, non-aqueous secondary batteries using this separator also exhibit excellent battery characteristics (rate characteristics and high-temperature cycle characteristics).

[0014] <Aqueous medium> Here, the aqueous medium refers to an aqueous dispersion medium or an aqueous solvent. Although water is preferably used as the aqueous medium, water-soluble solvents can also be used if necessary, such as alcohols, glycols, cellosolves, amino alcohols, amines, ketones, carboxylic acid amides, phosphoric acid amides, sulfoxides, carboxylic acid esters, phosphoric acid esters, ethers, and nitriles.

[0015] <Polymer (A1)> First, the polymer (A1) used in the present invention will be described. The polymer (A1) is obtained by polymerizing an ethylenically unsaturated monomer mixture. The ethylenically unsaturated monomer mixture contains at least an ethylenically unsaturated monomer (a-1) having an amide group, and an ethylenically unsaturated monomer (a-2) having at least one functional group selected from the group consisting of an alkyl group having 8 or more carbon atoms, a styrenated phenyl group, and an alkylene oxide group having 3 or more carbon atoms, and a hydrophilic group. If necessary, it may contain another ethylenically unsaturated monomer (a-3) copolymerizable with the ethylenically unsaturated monomer (a-1) and the ethylenically unsaturated monomer (a-2). In the slurry composition for a nonaqueous secondary battery separator, the polymer (A1) functions as a dispersion aid by adsorbing to the inorganic fine particles, and also has the effect of improving the wettability and coatability to the substrate. After the slurry composition for a nonaqueous secondary battery separator is applied to the substrate and dried, the polymer (A1) also functions as a binder that firmly bonds between the inorganic fine particles and between the inorganic fine particles and the substrate, thereby suppressing thermal shrinkage.

[0016] The ethylenically unsaturated monomer mixture contains 40.0 to 99.8 mass% of the ethylenically unsaturated monomer (a-1) and 0.2 to 60.0 mass% of the ethylenically unsaturated monomer (a-2), based on the total mass (100 mass%).

[0017] The content of the ethylenically unsaturated monomer (a-1) is 40.0 to 99.8% by mass, preferably 50 to 99.0% by mass. When the content of the ethylenically unsaturated monomer (a-1) is 40.0% by mass or more, the polymer (A1) adheres firmly to the inorganic fine particles and forms a tough coating film, thereby enabling the separator to exhibit excellent heat resistance, adhesion, and abrasion resistance. With the improvement in separator performance, the battery characteristics of the secondary battery are also significantly improved. On the other hand, when the content is 99.8% by mass or less, the flexibility of the separator and the ionic conductivity of the battery are improved, resulting in excellent battery characteristics.

[0018] The content of the ethylenically unsaturated monomer (a-2) is in the range of 0.2 to 60.0 mass%, preferably 0.2 to 50.0 mass%, more preferably 0.3 to 30.0 mass%, and even more preferably 0.5 to 10.0 mass%. When the content of the ethylenically unsaturated monomer (a-2) is 0.2% by mass or more, the surface activity and dispersion stabilization of the polymer (A1) are dramatically improved, thereby significantly improving the storage stability of the slurry composition. Furthermore, the redispersibility of the slurry composition is excellent even after long-term storage at high temperatures, so that separators formed therefrom exhibit excellent heat resistance, adhesion, and abrasion resistance not only initially but also after storage. Furthermore, the wettability and adhesion of the polymer (A1) to olefin substrates are improved, so that the polymer (A1) firmly adheres to porous polyethylene substrates with a thickness of less than 10 μm, which are prone to heat shrinkage, thereby exhibiting excellent heat shrinkage suppression effects. Furthermore, the hydrophilicity derived from the ethylenically unsaturated monomer (a-2) improves the ionic conductivity of the polymer (A1), thereby improving battery performance. On the other hand, when the content is 60.0 mass% or less, unreacted ethylenically unsaturated monomer (a-2) is unlikely to remain, and free components do not adversely affect the heat resistance, adhesion, and abrasion resistance of the separator and the battery characteristics.

[0019] [Ethylenically unsaturated monomer (a-1)] The ethylenically unsaturated monomer (a-1) is an ethylenically unsaturated monomer having an amide group, and is selected from the group consisting of (meth)acrylamide, N-methoxymethyl-(meth)acrylamide, N-ethoxymethyl-(meth)acrylamide, N-propoxymethyl-(meth)acrylamide, N-butoxymethyl-(meth)acrylamide, N-pentoxymethyl-(meth)acrylamide, N,N-di(methoxymethyl)acrylamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N,N-di(ethoxymethyl)acrylamide, N-ethoxymethyl-N-propoxymethylmethacrylamide, N,N-di(propoxymethyl)acrylamide, N-butoxymethyl-N- Examples of suitable ethylenically unsaturated monomers include (propoxymethyl)methacrylamide, N,N-di(butoxymethyl)acrylamide, N-butoxymethyl-N-(methoxymethyl)methacrylamide, N,N-di(pentoxymethyl)acrylamide, N-methoxymethyl-N-(pentoxymethyl)methacrylamide, N,N-dimethylaminopropylacrylamide, N,N-diethylaminopropylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, diacetoneacrylamide, vinylpyrrolidone, vinylacetamide, methylenebisacrylamide, hydroxymethylacrylamide, and 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof. These may be used alone or in combination of two or more in any ratio. Among these, it is preferable that the ethylenically unsaturated monomer (a-1) contains (meth)acrylamide, from the viewpoints of superior adhesion to inorganic fine particles and further improving the heat resistance, adhesion, and durability of the separator and battery characteristics.

[0020] The content of (meth)acrylamide in 100% by mass of the ethylenically unsaturated monomer (a-1) is preferably 50.0% by mass or more, more preferably 60.0 to 100% by mass, and even more preferably 80.0 to 100% by mass, thereby improving the heat resistance of the separator.

[0021] [Ethylenically unsaturated monomer (a-2)] The ethylenically unsaturated monomer (a-2) is an ethylenically unsaturated monomer having at least one functional group selected from the group consisting of an alkyl group having 8 or more carbon atoms, a styrenated phenyl group, and an alkylene oxide group having 3 or more carbon atoms, and a hydrophilic group, and is polymerizable while also functioning as a surfactant.

[0022] The alkyl group having 8 or more carbon atoms, the styrenated phenyl group, or the alkylene oxide group having 3 or more carbon atoms imparts excellent surface activity to the polymer (A1) and functions to enable effective adsorption to the surface of the inorganic fine particles and the interface of the substrate. Among these, it is more preferable to have an alkyl group having 8 or more carbon atoms, from the viewpoint of excellent surface activity, storage stability of the slurry composition, and various physical properties of the separator.

[0023] Examples of alkyl groups having 8 or more carbon atoms include linear or branched octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, and octadecyl groups. Octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and hexadecyl groups are preferred because they provide more excellent surface activity and provide good storage stability to the slurry composition.

[0024] Examples of the alkylene oxide group having 3 or more carbon atoms include a propylene oxide (PO) group, a butylene oxide (BO) group, etc. The butylene oxide group is preferred because it has better surface activity and the storage stability of the slurry composition is good.

[0025] The hydrophilic group functions as a hydrophilic dispersion site, and improves the dispersion stabilizing ability of the polymer (A1). Specific examples of the hydrophilic group include a polyethylene oxide (EO) group, sulfonic acid or a salt thereof, phosphoric acid or a salt thereof, and a combination of these hydrophilic groups. Among these, from the viewpoint of achieving a more excellent dispersion stabilizing ability and further improving the stability of the slurry composition, at least one of a polyethylene oxide group and a sulfonate group is preferred, and it is more preferred to have a polyethylene oxide group and a sulfonate group.

[0026] The ethylenically unsaturated monomer (a-2) preferably contains an ethylenically unsaturated monomer represented by any of the general formulae (1) to (4), because this significantly improves the surface activity and dispersion stabilization of the polymer (A1), improves the storage stability of the slurry composition, and further improves the heat resistance and adhesion of the separator and the battery characteristics.

[0027] General formula (1) [ka] (In the general formula (1), R is an alkyl group having 8 to 16 carbon atoms, and X 1 is an ethylene oxide group with an average number of added moles of 10 to 50, Y 1 represents a hydrogen atom or a sulfonate group.

[0028] General formula (2) [ka] (In the general formula (2), R is an alkyl group having 8 to 16 carbon atoms, and X 2 is an ethylene oxide group with an average number of added moles of 10 to 50, Y 2 represents a hydrogen atom or a sulfonate group.

[0029] General formula (3) [ka] (In general formula (3), X 3 The number of moles of carbon atoms is 3 or more. 20 alkylene oxide groups, Y 3 represents an ethylene oxide group having an average number of added moles of 10 to 50, and Z represents a hydrogen atom or a sulfonate group.

[0030] General formula (4) [ka] (In the general formula (4), m is an integer of 1 to 4, and X 4 is an ethylene oxide group with an average number of added moles of 10 to 50, Y 4 represents a hydrogen atom or a sulfonate group.

[0031] The ethylenically unsaturated monomer (a-2) may be synthesized or may be a commercially available product. Examples of commercially available ethylenically unsaturated monomers (a-2) include: Examples of the ethylenically unsaturated monomer represented by general formula (1) include the Aqualon KH series (polyoxyethylene alkyl ether sulfate salt type) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., specifically KH-05 (the alkyl group has 10 to 12 carbon atoms, the average number of moles of EO added is 5), KH-10 (the alkyl group has 10 to 12 carbon atoms, the average number of moles of EO added is 10), KH-20 (the alkyl group has 10 to 12 carbon atoms, the average number of moles of EO added is 20), and the Aqualon KN series (polyoxyethylene alkyl ether type) (specifically KN-10 (the alkyl group has 10 to 12 carbon atoms, the average number of moles of EO added is 10), KN-20 (the alkyl group has 10 to 12 carbon atoms, the average number of moles of EO added is 20), KN-30 (the alkyl group has 10 to 12 carbon atoms, the average number of moles of EO added is 30), and KN-5065 (the average number of moles of EO added is 50).

[0032] Examples of the ethylenically unsaturated monomer represented by general formula (2) include the ADEKA Reasoap SR series (polyoxyethylene alkyl ether sulfate salts) manufactured by ADEKA Corporation, specifically SR-10 (the number of carbon atoms in the alkyl group is 10 to 12, the average number of moles added by EO is 10), SR-20 (the number of carbon atoms in the alkyl group is 10 to 12, the average number of moles added by EO is 20), and SR-30 (the number of carbon atoms in the alkyl group is 10 to 12, the average number of moles added by EO is 30), and the ADEKA Reasoap ER series (polyoxyethylene alkyl ethers), specifically ER-10 (the number of carbon atoms in the alkyl group is 10 to 12, the average number of moles added by EO is 10), ER-20 (the number of carbon atoms in the alkyl group is 10 to 12, the average number of moles added by EO is 20), ER-30 (the number of carbon atoms in the alkyl group is 10 to 12, the average number of moles added by EO is 30), and ER-40 (the number of carbon atoms in the alkyl group is 10 to 12, the average number of moles added by EO is 40).

[0033] Examples of the ethylenically unsaturated monomer represented by general formula (3) include the Ramtel PD series (polyoxyethylene alkylene ether type) manufactured by Kao Corporation, specifically PD-104 (polyoxyethylene alkylene alkenyl ether sulfate having a repeating structure of BO groups and EO groups), PD-420, 430, and 450 (polyoxyethylene alkylene alkenyl ether having BO and EO units; 420 has an average number of moles of EO added of 20, 430 has an average number of moles of EO added of 30, and 450 has an average number of moles of EO added of 50), etc.

[0034] Examples of the ethylenically unsaturated monomer represented by general formula (4) include the Aqualon AR series (polyoxyethylene styrenated propenyl phenyl ether sulfate salts) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., specifically AR-10 (average number of moles of EO added: 10), AR-20 (average number of moles of EO added: 20), and AR-30 (average number of moles of EO added: 30), and the Aqualon AN series (polyoxyethylene styrenated propenyl phenyl ethers) specifically AN-10 (average number of moles of EO added: 10), AN-20 (average number of moles of EO added: 20), AN-30 (average number of moles of EO added: 30), and AN-5065 (average number of moles of EO added: 50).

[0035] Commercially available polyoxyethylene alkyl ether phosphate products include Croda's Maximal 6106 and 6112. Commercially available alkylsulfosuccinate ester products include Eleminol JS-20 manufactured by Sanyo Chemical Industry Co., Ltd. Commercially available polyoxyethylene nonylphenyl ether sulfate products include the Aqualon HS series manufactured by Daiichi Kogyo Seiyaku, specifically HS-10 (average number of moles of EO added: 10), HS-20 (average number of moles of EO added: 20), HS-30 (average number of moles of EO added: 30), BC-10 (average number of moles of EO added: 10), BC-20 (average number of moles of EO added: 20), etc. Commercially available polyoxyethylene nonylphenyl ethers include the Aqualon RN series manufactured by Daiichi Kogyo Seiyaku, specifically RN-10 (average number of moles of EO added: 10), RN-20 (average number of moles of EO added: 20), RN-30 (average number of moles of EO added: 30), and RN-50 (average number of moles of EO added: 50). Commercially available polyoxyethylene polycyclic phenyl ether methacrylate sulfate products include Antox MS-60 manufactured by Sanyo Chemical Industries, Ltd.

[0036] The total content of the ethylenically unsaturated monomers represented by the general formulae (1) to (4) in 100% by mass of the ethylenically unsaturated monomer (a-2) is preferably 50% by mass or more, more preferably 60 to 100% by mass, and even more preferably 80 to 100% by mass, which allows the slurry composition to have excellent storage stability.

[0037] [Ethylenically unsaturated monomer (a-3)] The ethylenically unsaturated monomer (a-3) is another ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated monomer (a-1) and the ethylenically unsaturated monomer (a-2). The ethylenically unsaturated monomer (a-3) can be copolymerized with the ethylenically unsaturated monomer (a-1) and the ethylenically unsaturated monomer (a-2) in order to control the glass transition temperature (Tg), weight average molecular weight, average particle size, etc. of the polymer (A1).

[0038] Other ethylenically unsaturated monomers (a-3) include, for example, aromatic ethylenically unsaturated compounds such as vinylnaphthalene, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, phenoxyhexaethylene glycol (meth)acrylate, phenoxyhexaethylene glycol (meth)acrylate, and phenyl (meth)acrylate; linear or branched alkyl group-containing ethylenically unsaturated monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, heptyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, and behenyl (meth)acrylate; cycloalkyl group-containing ethylenically unsaturated monomers such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; Fluorinated alkyl group-containing ethylenically unsaturated monomers such as trifluoroethyl (meth)acrylate and heptadecafluorodecyl (meth)acrylate; nitrile group-containing ethylenically unsaturated monomers such as (meth)acrylonitrile; Sulfo group-containing ethylenically unsaturated monomers such as methallylsulfonic acid, methallylsulfonic acid, sodium methallylsulfonate, allylsulfonic acid, sodium allylsulfonate, ammonium allylsulfonate, and vinylsulfonic acid; hydroxyl group-containing ethylenically unsaturated monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol mono(meth)acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, and allyl alcohol; Polyoxyethylene group-containing ethylenically unsaturated monomers such as methoxypolyethylene glycol (meth)acrylate and polyethylene glycol (meth)acrylate; Examples thereof include dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methylethylaminoethyl (meth)acrylate, dimethylaminostyrene, and diethylaminostyrene, and amino group-containing ethylenically unsaturated monomers such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and methylethylaminoethyl (meth)acrylate; Epoxy group-containing ethylenically unsaturated monomers such as glycidyl (meth)acrylate and 3,4-epoxycyclohexyl (meth)acrylate; Ketone group-containing ethylenically unsaturated monomers such as acetoacetoxy (meth)acrylate; Allyl (meth)acrylate, 1-methylallyl (meth)acrylate, 2-methylallyl (meth)acrylate, 1-butenyl (meth)acrylate, 2-butenyl (meth)acrylate, 3-butenyl (meth)acrylate, 1,3-methyl-3-butenyl (meth)acrylate, 2-chloroallyl (meth)acrylate, 3-chloroallyl (meth)acrylate, o-allylphenyl (meth)acrylate, 2-(allyloxy)ethyl (meth)acrylate, allyl lactyl (meth)acrylate, citronellyl (meth)acrylate, geranyl (meth)acrylate, rosinyl (meth)acrylate, cinnamyl (meth)acrylate, diallyl maleate, diaryl itaconic acid, vinyl (meth)acrylate, vinyl crotonate Ethylenically unsaturated monomers having two or more ethylenically unsaturated groups, such as vinyl, vinyl oleate, vinyl linoleate, 2-(2'-vinyloxyethoxy)ethyl (meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol (meth)acrylate, tetraethylene glycol (meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxymethylpropane triacrylate, divinylbenzene, divinyl adipate, diallyl isophthalate, diallyl phthalate, and diallyl maleate; Alkoxysilyl group-containing ethylenically unsaturated monomers such as γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltributoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxymethyltrimethoxysilane, γ-acryloxymethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, and vinylmethyldimethoxysilane; These include, but are not limited to, the following.

[0039] Among these, from the viewpoint of achieving superior storage stability of the slurry composition and good adhesion and corrosion resistance of the separator, it is preferable that the ethylenically unsaturated monomer (a-3) contains any of styrene, benzyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, (meth)acrylonitrile, and 3-(meth)acryloxypropyltriethoxysilane.

[0040] When the ethylenically unsaturated monomer (a-3) is used in the polymerization of the polymer (A1), the ethylenically unsaturated monomer (a-3) is preferably contained in an amount of 0.5 to 45.0 mass%, and more preferably 5 to 30.0 mass%, based on 100 mass% of the total mass of the ethylenically unsaturated monomer mixture. By containing the ethylenically unsaturated monomer (a-3) in this range, the storage stability of the slurry composition is further improved, and the heat resistance, adhesion, and corrosion resistance of the separator can also be improved.

[0041] [Method for producing polymer (A1)] The method for polymerizing the ethylenically unsaturated monomer mixture to produce the polymer (A1) is not particularly limited and may be solution polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, or the like. However, it is preferable to use emulsion polymerization, since it is possible to easily obtain a resin composition containing the polymer (A1) having a high molecular weight, low viscosity, and high solid content in an aqueous medium. The solid content concentration of the polymer (A1) in the resin composition is not particularly limited, but is preferably 5.0 to 60.0% by mass.

[0042] The polymer (A1) may be a water-soluble polymer or a water-insoluble polymer dispersed in an aqueous medium and used as a particulate polymer. That is, the resin composition for a nonaqueous secondary battery separator containing the polymer (A1) and an aqueous medium may be a polymer (A1) solution or a polymer (A1) dispersion, but from the viewpoints of good ionic conductivity in the separator and excellent battery characteristics, it is more preferable that the polymer (A1) be a particulate polymer and be a dispersion.

[0043] (Radical polymerization initiator) As the radical polymerization initiator used in the polymerization reaction of the ethylenically unsaturated monomer mixture, known oil-soluble polymerization initiators and water-soluble polymerization initiators can be used. The radical polymerization initiator is preferably used in an amount of 0.1 to 4 parts by mass, more preferably 0.2 to 2 parts by mass, based on 100 parts by mass of the ethylenically unsaturated monomer mixture.

[0044] The oil-soluble polymerization initiator is not particularly limited, and examples thereof include organic peroxides such as benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butylperoxy(2-ethylhexanoate), tert-butylperoxy-3,5,5-trimethylhexanoate, and di-tert-butyl peroxide; and azobis compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and 1,1'-azobis-cyclohexane-1-carbonitrile.

[0045] In emulsion polymerization, it is preferable to use a water-soluble polymerization initiator. As the water-soluble polymerization initiator, for example, conventionally known ones such as ammonium persulfate (APS), potassium persulfate (KPS), hydrogen peroxide, and 2,2'-azobis(2-methylpropionamidine) dihydrochloride can be suitably used.

[0046] (reducing agent) In emulsion polymerization, a reducing agent may be used in combination with the polymerization initiator. The use of a reducing agent in combination accelerates the emulsion polymerization rate and facilitates emulsion polymerization at low temperatures. Examples of reducing agents include reducing organic compounds such as ascorbic acid, erythorbic acid, tartaric acid, citric acid, glucose, and metal salts of formaldehyde sulfoxylate; reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, sodium bisulfite, and sodium metabisulfite; ferrous chloride, Rongalit, and thiourea dioxide. The reducing agent is preferably used in an amount of 0.05 to 5 parts by mass per 100 parts by mass of the ethylenically unsaturated monomer mixture.

[0047] The polymerization temperature may be equal to or higher than the polymerization initiation temperature of the polymerization initiator, and for example, in the case of a peroxide-based polymerization initiator, the polymerization temperature is usually about 80°C. The polymerization time is not particularly limited, but is usually 2 to 24 hours. The ethylenically unsaturated monomer mixture may also be polymerized by photochemical reaction or radiation irradiation, without using the above-mentioned polymerization initiator.

[0048] (Buffer or chain transfer agent) In the polymerization of the ethylenically unsaturated monomer mixture, a buffer or chain transfer agent may be further used as necessary. Examples of the buffer include sodium acetate, sodium citrate, and sodium bicarbonate. Examples of the chain transfer agent include n-hexyl mercaptan, n-heptyl mercaptan, t-hexyl mercaptan, t-heptyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, n-nonyl mercaptan, t-nonyl mercaptan, n-decyl mercaptan, t-decyl mercaptan, n-undecyl mercaptan, t-undecyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tridecyl mercaptan, t-tridecyl mercaptan, n-tetradecyl mercaptan, and t-tetradecyl mercaptan. Examples of the mercaptan include mercaptan, n-heptadecyl mercaptan, t-heptadecyl mercaptan, t-hexadecyl mercaptan, n-hexadecyl mercaptan, n-heptadecyl mercaptan, n-octadecyl mercaptan, t-heptadecyl mercaptan, t-octadecyl mercaptan, mercaptan 2-ethylhexyl mercaptoacetate, octyl mercaptoacetate, methoxybutyl mercaptopropionate, 2-ethylhexyl mercaptopropionate, octyl mercaptopropionate, and stearyl mercaptopropionate. The buffer is preferably used in an amount of 0 to 1 part by mass, more preferably 0.05 to 0.5 part by mass, per 100 parts by mass of the ethylenically unsaturated monomer mixture. The chain transfer agent is preferably used in an amount of 0.4 to 3 parts by mass, more preferably 0.6 to 2 parts by mass, per 100 parts by mass of the ethylenically unsaturated monomer mixture.

[0049] (basic compounds) During or after the polymerization of the ethylenically unsaturated monomer mixture, a basic compound may be used as a neutralizing agent to enhance the stability of the polymer (A1). Examples of basic compounds include various organic amines such as aqueous ammonia, dimethylaminoethanol, diethanolamine, and triethanolamine; and inorganic alkali agents such as alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide. The basic compound may be added after the completion of the first dropwise addition or after the completion of the reaction. The basic compound is preferably used in an amount of 0.75 to 1.2 mol based on 1 mol of carboxy groups in the polymer (A1).

[0050] [Acid value] The acid value of the polymer (A1) is preferably in the range of 0 to 50 mgKOH / g, more preferably in the range of 0 to 15 mgKOH / g. When the acid value is in this range, the amide groups in the polymer (A1) are less likely to hydrolyze, and deterioration of the polymer (A1) over time is suppressed, further improving the storage stability of the slurry composition. Therefore, even separators produced from the slurry composition after storage at high temperatures exhibit good heat resistance and adhesion, and further improve battery performance. The acid value of the polymer (A1) can be appropriately adjusted by the amount of the ethylenically unsaturated monomer having a carboxy group introduced.

[0051] [Average particle size] When the polymer (A1) is a particulate polymer, the average particle size, as measured by dynamic light scattering of a polymer dispersion at a solids concentration of 1% by mass, is preferably in the range of 10 to 5,000 nm, more preferably 50 to 3,000 nm. When the average particle size of the polymer (A1) is 10 nm or more, the permeability of the electrolyte is improved and the ionic conductivity is also improved, thereby further improving the battery characteristics. On the other hand, when the average particle size is 5,000 nm or less, stronger bonding can be achieved between the inorganic particles and between the inorganic particles and the substrate, thereby further improving the heat resistance, adhesion, and abrasion resistance of the separator and the battery characteristics.

[0052] The average particle size can be determined by, for example, dynamic light scattering measurement (measuring equipment manufactured by Nanotrac UPA Co., Ltd. or Microtrac Bell Co., Ltd.). The peak of the volume particle size distribution data (histogram) obtained at this time is taken as the average particle size.

[0053] [Glass transition temperature] The glass transition temperature (Tg) of the polymer (A1) is preferably in the range of 80 to 220°C, more preferably in the range of 90 to 200°C. By having a Tg in this range, when a slurry composition is prepared, the inorganic fine particles are firmly bound together, and the protective layer exhibits better adhesion and conformability to the substrate. Furthermore, the good adhesion and conformability result in better heat resistance, adhesion, and abrasion resistance of the separator, which is preferable because it can also improve battery characteristics. The glass transition point can be determined by measurement using a DSC (differential scanning calorimeter manufactured by TA Instruments).

[0054] <Slurry composition for non-aqueous secondary battery separator> The slurry composition for a non-aqueous secondary battery separator is used to form a protective layer used in a non-aqueous secondary battery separator, and contains at least inorganic fine particles and the resin composition for a non-aqueous secondary battery separator of the present invention, and can optionally further contain additive components. The slurry composition for a nonaqueous secondary battery separator of the present invention has excellent storage stability, and therefore has good wettability and adhesion to a substrate not only initially but also after long-term storage at high temperatures, and can form a protective layer that is excellent in heat resistance, adhesion, and weather resistance.

[0055] <Inorganic fine particles> The inorganic fine particles form a porous structure with excellent heat resistance on an olefin substrate or various electrodes. The inorganic fine particles are preferably particles that do not dissolve in the dispersion medium of the slurry composition for a nonaqueous secondary battery or the nonaqueous electrolyte of the secondary battery and that maintain their shape. Furthermore, the inorganic fine particles are preferably electrochemically stable and stable even under the operating environment of the secondary battery.

[0056] As the inorganic fine particles, fine particles of any inorganic compound can be used as long as they are non-conductive particles that do not adversely affect the separator or the physical properties of the battery. Examples of inorganic fine particles include oxide particles such as aluminum oxide (alumina), aluminum oxide hydrate (boehmite (AlOOH), gibbsite (Al(OH)3), silicon oxide, magnesium oxide (magnesia), calcium oxide, titanium oxide (titania), barium titanate (BaTiO3), ZrO, and alumina-silica composite oxide; nitride particles such as aluminum nitride and boron nitride; covalently bonded crystalline particles such as silicon and diamond; sparingly soluble ionic crystalline particles such as barium sulfate, calcium fluoride, and barium fluoride; fine clay particles such as talc and montmorillonite; These particles may be subjected to element substitution, surface treatment, solid solution formation, etc., as necessary. Among the inorganic fine particles listed above, it is more preferable to use fine particles of barium sulfate or alumina, in view of the excellent dispersion stability of the slurry composition for a nonaqueous secondary battery separator, the heat resistance of the separator, and the resistance to various coating films.

[0057] The inorganic fine particles preferably have an average particle size in the range of 0.2 to 5.0 μm, more preferably 0.3 to 2.0 μm. When the inorganic fine particles have an average particle size in the above range, the separator has better heat resistance and coating resistance, and the ion conductivity is less likely to deteriorate, resulting in a secondary battery with better battery characteristics. The average particle diameter of inorganic microparticles can be measured by taking an image of the particle powder observed at a magnification of 15,000 times using a scanning electron microscope (SEM) (JEOL Ltd.'s "JSM-7800F"), importing it into image processing software (Mitani Shoji Co., Ltd.'s "Winroof"), extracting the spherical structure, and measuring the average value of the circle-equivalent diameter of each particle.

[0058] In the slurry composition for a nonaqueous secondary battery separator, the polymer (A1) is preferably contained in an amount of 0.5 to 4.0 parts by mass, more preferably 1.0 to 3.0 parts by mass, per 100 parts by mass of inorganic fine particles. By containing the polymer (A1) in this range, the storage stability of the slurry composition is further improved, and even in a separator prepared by applying the slurry composition stored at high temperature for a long period of time, the separator exhibits superior heat resistance, adhesion, and abrasion resistance, while being less likely to adversely affect battery characteristics.

[0059] <Polymer (A2)> The slurry composition for a nonaqueous secondary battery separator of the present invention preferably further contains a polymer (A2), and the polymer (A2) is a particulate polymer having a glass transition temperature (Tg) of -40 to 40°C. The polymer (A2) does not fall under the category of polymer (A1). When the polymer (A2) is made into a slurry composition, it functions as an adhesive component to the substrate, and can further improve the binding strength between inorganic fine particles or between the inorganic fine particles and the substrate.

[0060] The polymer (A2) is not limited to any polymer as long as it has a glass transition temperature of −40 to 40° C. and is a particulate polymer, and any component can be used, such as an acrylic resin, a styrene-acrylic resin, a butadiene-based resin, an olefin resin, a urethane resin, a polyester resin, or a natural polymer such as a polysaccharide. However, from the viewpoints of mixing stability with the polymer (A1) and good adhesion to inorganic fine particles and olefin substrates, it is preferable to use an acrylic resin or a styrene-acrylic resin.

[0061] When the polymer (A2) has a glass transition temperature (Tg) of −40 to 40° C., the conformability of the protective layer to the substrate improves, and a separator with excellent adhesion and corrosion resistance can be obtained.

[0062] The slurry composition for a nonaqueous secondary battery separator preferably contains 5.0 to 320.0 parts by mass of polymer (A2) per 100 parts by mass of polymer (A1), and more preferably 8.0 to 200.0 parts by mass of polymer (A2). By containing polymer (A2) in this range, a separator with better adhesion and corrosion resistance can be obtained, and the battery characteristics of the secondary battery can also be improved.

[0063] When polymer (A2) is a polymer of an ethylenically unsaturated monomer, polymer (A2) can be produced by the same polymerization method using the same ethylenically unsaturated monomer as described for polymer (A1). Polymer (A2) is a particulate polymer dispersed in an aqueous medium, which facilitates adhesion to substrates. Furthermore, polymer (A2) preferably has an average particle size of 50 to 500 nm, more preferably 60 to 400 nm, at a solids concentration of 0.1% by mass. By having the average particle size within the above range, when a slurry composition is prepared, the gaps between inorganic fine particles are not filled, resulting in good ion permeability of the separator.

[0064] The average particle size can be determined by, for example, dynamic light scattering measurement (measuring equipment manufactured by Nanotrac UPA Co., Ltd. or Microtrac Bell Co., Ltd.). The peak of the volume particle size distribution data (histogram) obtained at this time is taken as the average particle size.

[0065] <Optional ingredients> The slurry composition for a nonaqueous secondary battery separator of the present invention may contain various additives as optional components, such as other polymers than the polymer (A1) and the polymer (A2), antifoaming agents, leveling agents, preservatives, solvents, crosslinking agents, dispersants, binders, etc. If the optional components remain in the protective layer, it is more preferable that they do not adversely affect the physical properties of the separator or the battery.

[0066] <Separator for non-aqueous secondary batteries> The non-aqueous secondary battery separator of the present invention is a separator having a substrate on one or both sides of which a protective layer is formed from the slurry composition for a non-aqueous secondary battery separator. The protective layer can be formed by applying the slurry composition for a non-aqueous secondary battery separator to a substrate and then volatilizing volatile components in a drying step.

[0067] <Base material> The substrate used for the separator is not particularly limited, but includes known substrates such as organic separator substrates. The organic separator substrate is an organic material having a porous structure. Examples of the organic separator substrate include a microporous film containing a polyolefin resin such as polyethylene or polypropylene, or an aromatic polyamide resin, or a nonwoven fabric. Among these substrates, a polyethylene substrate is preferably used because of its excellent safety and battery characteristics.

[0068] The thickness of the substrate can be any thickness, preferably in the range of 5.0 to 30 μm, more preferably in the range of 5.0 to 10 μm. By keeping the thickness of the substrate within the above range, the safety of the battery is sufficiently ensured while good ion conductivity is maintained, thereby enabling the development of better battery characteristics.

[0069] <Protective layer> The thickness of the protective layer is preferably 1.0 to 5.0 μm, and more preferably 1.5 to 3.5 μm. When the thickness of the protective layer is in the above range, the separator has better heat resistance and the battery characteristics are also improved, which is preferable.

[0070] <Separator manufacturing method> As a method for forming a protective layer on a substrate, the slurry composition is applied to the substrate using a bar coater or the like, and then dried, or the slurry composition is applied to a release substrate, dried to produce a protective layer, and then transferred to the surface of the substrate, etc. However, from the viewpoint of being able to form a homogeneous protective layer with high precision, the method of applying the slurry composition to the substrate and then drying is preferred. In the coating step, the method of applying the slurry composition to the substrate is not particularly limited, and for example, methods such as a doctor blade method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a brush coating, and a bar coating can be mentioned.

[0071] ≪Nonaqueous secondary battery≫ The nonaqueous secondary battery of the present invention includes the nonaqueous secondary battery separator. More specifically, the nonaqueous secondary battery includes a positive electrode, a negative electrode, the nonaqueous secondary battery separator, and an electrolyte. The nonaqueous secondary battery of the present invention exhibits excellent battery characteristics (e.g., high-temperature cycle characteristics and output characteristics) because the nonaqueous secondary battery separator has excellent heat resistance, adhesion, and abrasion resistance.

[0072] <Positive or negative electrode> The positive and negative electrodes used in the secondary battery of the present invention may be electrodes formed by forming an electrode mixture layer containing various active materials, binder components, etc. on a current collector.

[0073] [Cathode active material] The positive electrode active material is not particularly limited. In the case of lithium-ion batteries, metal compounds such as metal oxides and metal sulfides capable of doping or intercalating lithium ions, as well as conductive polymers, can be used. Examples of metal oxides or metal compounds include oxides of transition metals such as Fe, Co, Ni, and Mn, composite oxides with lithium, and inorganic compounds such as transition metal sulfides. Specific examples of metal oxides or metal compounds include transition metal oxide powders such as MnO, VO, VO, and TiO; composite oxide powders of lithium and transition metals such as layered lithium nickel oxide, lithium cobalt oxide, lithium manganate, and spinel-structured lithium manganate; lithium iron phosphate-based materials, which are lithium oxide compounds with an olivine structure; and transition metal sulfide powders such as TiS and FeS. These materials can be used alone or in combination.

[0074] [Negative electrode active material] Examples of negative electrode active materials include metal Li, alloys containing metal Li (e.g., tin alloys, silicon alloys, lead alloys), metal oxides such as lithium titanate, lithium vanadate, and lithium silicate, conductive polymers such as polyacetylene and poly-p-phenylene, amorphous carbon materials such as soft carbon and hard carbon, artificial graphite such as highly graphitized carbon materials, carbonaceous powders such as natural graphite, carbon black, mesophase carbon black, resin-baked carbon materials, vapor-grown carbon fibers, and carbon materials such as carbon fibers. These materials can be used alone or in combination of two or more.

[0075] [Electrode binder] As the binder for the electrode, those exemplified in the slurry composition for the nonaqueous secondary battery separator can be used.

[0076] [Current collector] Examples of the current collector include metals such as aluminum, copper, nickel, titanium, and stainless steel, and alloys thereof.

[0077] <Electrolyte> The electrolyte used in the secondary battery of the present invention is typically an organic electrolyte solution in which a supporting electrolyte is dissolved in an organic solvent. For example, in lithium-ion secondary batteries, a lithium salt is used as the supporting electrolyte. Examples of lithium salts include LiPF, LiAsF, LiBF, LiSbF, LiAlCl, LiClO, CFSOLi, CFSOLi, CFCoLi, (CFCO)NLi, (CFSO)NLi, and (CFSO)NLi. Among these, LiPF, LiClO, and CFSOLi are preferred because they are easily soluble in solvents and exhibit a high degree of dissociation. Generally, the use of a supporting electrolyte with a higher degree of dissociation tends to result in higher lithium ion conductivity, and the lithium ion conductivity can be adjusted by the type of supporting electrolyte. The organic solvent used in the electrolyte is not particularly limited as long as it can dissolve the supporting electrolyte. For example, in lithium ion secondary batteries, carbonates such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), ethyl methyl carbonate (EMC), and vinylene carbonate (VC) are preferred. esters such as γ-butyrolactone and methyl formate are also suitable. Ethers such as 1,2-dimethoxyethane and tetrahydrofuran are also suitable. Sulfur-containing compounds such as sulfolane and dimethyl sulfoxide are also suitable. Mixtures of these solvents may also be used. Among these, carbonates are preferred due to their high dielectric constant and wide stable potential range. Generally, the lower the viscosity of the solvent used, the higher the lithium ion conductivity. Therefore, the lithium ion conductivity can be adjusted by the type of solvent. The concentration of the electrolyte in the electrolyte can be adjusted as needed. Known additives may also be added to the electrolyte.

[0078] <Method of manufacturing non-aqueous secondary battery> The nonaqueous secondary battery of the present invention can be produced, for example, by stacking a positive electrode and a negative electrode with a separator interposed therebetween, rolling or folding the stack as necessary, placing the stack in a battery container, injecting an electrolyte into the battery container, and sealing the container. If necessary, the battery container may contain an expanded metal, a fuse, an overcurrent protection element such as a PTC element, a lead plate, or the like to prevent pressure buildup within the battery and overcharging and discharging. Examples of the battery shape include coin, button, sheet, cylindrical, rectangular, and flat types. [Example]

[0079] The present invention will be described in more detail below with reference to examples, but the following examples do not limit the scope of the invention in any way. In the examples, "parts" means "parts by mass," "%" means "% by mass," and the values ​​in the tables are solid content masses, and blank spaces indicate empty spaces. The average particle size, acid value and glass transition temperature of the polymer were measured as follows.

[0080] <Average particle size> The average particle size was measured by diluting the resin composition with water to a solid content of 1% by mass, and measuring approximately 5 ml of the diluted solution using a dynamic light scattering measurement method (measuring device manufactured by Nanotrac UPA Co., Ltd., Microtrac Bell Co., Ltd.). The peak of the volume particle size distribution data (histogram) obtained at this time was taken as the average particle size. Note that if the polymer was completely dissolved in water and no peak was obtained by the above method, it was considered to be a water-soluble resin.

[0081] <Acid value> The acid value of the polymer is the number of milligrams of potassium hydroxide required to neutralize the acidic components contained in 1 g of dried resin. It was calculated by potentiometric titration of the dried polymer (A) with a potassium hydroxide-ethanol solution according to the method described in JIS K2501.

[0082] <Glass transition temperature (Tg)> The glass transition temperature of the polymer was measured using a DSC (differential scanning calorimeter, manufactured by TA Instruments). Specifically, an aluminum pan containing approximately 3 mg of dried resin and an empty aluminum pan as a reference were set in a DSC measurement holder, and the glass transition temperature was calculated from the baseline shift in the DSC curve obtained by measuring at a temperature increase rate of 10°C / min. The glass transition temperature (Tg) was calculated.

[0083] <Preparation of Polymer (A2-1) Dispersion> 22.0 parts of methyl methacrylate, 36.0 parts of n-butyl acrylate, 40.0 parts of 2-ethylhexyl acrylate, 0.4 parts of acrylic acid, 0.6 parts of acrylamide, 1.0 parts of 3-methacryloxypropyltriethoxysilane, 5.0 parts of a 20% aqueous solution of Daiichi Kogyo Seiyaku's Hitenol NF-08 (polyoxyethylene styrenated phenyl ether sulfate ester salt), and 40.4 parts of ion-exchanged water were mixed and stirred to prepare an emulsion of ethylenically unsaturated monomers. A reaction vessel equipped with a stirrer, thermometer, dropping funnel, and reflux condenser was charged with 68.9 parts of ion-exchanged water, 0.25 parts of a 20% aqueous solution of Daiichi Kogyo Seiyaku's Hitenol NF-08 as a surfactant, and 4.0% of the emulsion. The internal temperature was raised to 80 ° C. and thoroughly purged with nitrogen. 2.0 parts of a 5% aqueous solution of potassium persulfate was added as an initiator to initiate emulsion polymerization. While maintaining the internal temperature at 80°C, the remainder of the emulsion and 2.0 parts of a 5% aqueous solution of potassium persulfate were added dropwise over 3 hours, and the mixture was allowed to react for an additional 4 hours to obtain an aqueous dispersion of a particulate polymer. After the reaction, water was added to the resulting dispersion of the particulate polymer to adjust the resin solids content to 45.0%, thereby obtaining a dispersion of polymer (A2-1). Furthermore, the average particle size and Tg were measured using the same method as for the resin composition for nonaqueous secondary battery separators, and the average particle size of the particulate polymer was 169 nm, and the Tg was -36.0°C.

[0084] <Preparation of Polymer (A2-2) Dispersion> An emulsion of ethylenically unsaturated monomers was prepared by premixing and stirring 72.0 parts of methyl methacrylate, 27.0 parts of 2-ethylhexyl acrylate, 1.0 parts of acrylic acid, 5.0 parts of a 20% aqueous solution of Daiichi Kogyo Seiyaku's Hitenol NF-08 (polyoxyethylene styrenated phenyl ether sulfate ester salt), and 40.4 parts of ion-exchanged water. A reaction vessel equipped with a stirrer, thermometer, dropping funnel, and reflux condenser was charged with 68.9 parts of ion-exchanged water, 0.25 parts of a 20% aqueous solution of Daiichi Kogyo Seiyaku's Hitenol NF-08 as a surfactant, and 4.0% of the emulsion. The internal temperature was raised to 80°C and thoroughly purged with nitrogen. Then, 2.0 parts of a 5% aqueous solution of potassium persulfate was added as an initiator to initiate emulsion polymerization. While maintaining the internal temperature at 80°C, the remainder of the emulsion and 2.0 parts of a 5% aqueous solution of potassium persulfate were added dropwise over 3 hours, and the reaction was continued for another 4 hours to obtain an aqueous dispersion of particulate polymer. After the reaction, water was added to the resulting dispersion of the particulate polymer to adjust the resin solid content to 45.0%, thereby obtaining a polymer (A2-2) dispersion. The average particle size and Tg were measured in the same manner as in the non-aqueous secondary battery separator resin composition, and the average particle size of the particulate polymer was 172 nm, and Tg was 33.6 ° C.

[0085] [Example 1] <Preparation of Resin Composition for Non-Aqueous Secondary Battery Separator> A reaction vessel (reactor) equipped with a stirrer, thermometer, dropping funnel, and reflux condenser was charged with 458.3 parts of water and heated to 80°C while purging with nitrogen. Separately, a dropping vessel was premixed with 80.0 parts of acrylamide, 13.0 parts of methyl methacrylate, 5.0 parts of n-butyl methacrylate, 2.0 parts of ADEKA Rearsoap SR-10 (α-[1-[(allyloxy)methyl]-2-(nonylphenoxy)ethyl]-ω-polyoxyethylene sulfate ester salt, alkyl group carbon number 10-12, average EO molar addition number 10), and 66.7 parts of water. The resulting mixture was stirred and mixed to prepare an emulsion of ethylenically unsaturated monomers for dropwise addition to the reaction vessel. The reaction vessel was heated to 80°C and thoroughly purged with nitrogen. Polymerization was initiated by adding 1.0 parts of a 20% aqueous solution of ammonium persulfate as an initiator. The emulsion of ethylenically unsaturated monomer was added dropwise over 2 hours while maintaining the internal temperature at 80°C. After completion of the addition, the internal temperature was maintained at 80°C and the reaction was continued for an additional 6 hours. The resulting polymer (A) had an average particle size of 398 nm, an acid value of 0 mgKOH / g, and a glass transition temperature of 139.1°C. After completion of the reaction, water was added to adjust the nonvolatile component to 15.0 mass% to obtain a nonaqueous resin composition for secondary battery separators containing polymer (A1-1).

[0086] [Examples 2 to 14, Comparative Examples 1 to 4] A resin composition for a non-aqueous secondary battery separator was prepared in the same manner as in Example 1, except that the blending compositions and blending amounts (parts by mass) were changed to those shown in Tables 1 and 2. In Examples 3 and 8 and Comparative Examples 1 and 4, the ethylenically unsaturated monomer mixture in the dropping tank was in a homogeneous state, and the obtained resin was also in the form of a water-soluble resin. In Comparative Example 3, 2.0 parts of Hitenol LA-12 (polyoxyethylene lauryl ether ammonium sulfate) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. was further added to the ethylenically unsaturated monomer mixture in the dropping tank. The nonvolatile content of the obtained resin composition for a nonaqueous secondary battery separator was adjusted to 15.0 mass % by adding water or the like. The average particle size, acid value, and Tg of the nonaqueous secondary battery separator resin composition were measured in the same manner as in Example 1.

[0087] [Table 1]

[0088] [Table 2]

[0089] The abbreviations in the table are as follows: SR-10: Adeka Reasoap SR-10 manufactured by ADEKA Corporation (ethylenically unsaturated monomer represented by general formula (2); polymerizable polyoxyethylene alkyl ether sulfate ester salt surfactant, ethylene oxide (EO) addition mole number: 10) ER-30: ADEKA REASOAP ER-30 (ethylenically unsaturated monomer represented by general formula (2); polymerizable polyoxyethylene alkyl ether surfactant with EO addition mole number of 30) manufactured by ADEKA Corporation AR-10: Aqualon AR-10 (ethylenically unsaturated monomer represented by general formula (4): polyoxyethylene styrenated propenyl phenyl ether sulfate ammonium ester) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. PD-104: Latemul PD-104 manufactured by Kao Corporation (ethylenically unsaturated monomer represented by general formula (3); polyoxyethylene alkenyl ether ammonium sulfate, butylene oxide addition mole number 6, EO addition mole number 15) KH-10: Aqualon KH-10 (ethylenically unsaturated monomer represented by general formula (1); polyoxyethylene-1-(allyloxymethyl) alkyl ether sulfate ester ammonium) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Eleminol JS-20: Sanyo Chemical Industries, Ltd. Eleminol JS-20 (polymerizable alkylsulfosuccinate surfactant)

[0090] [Example 15] <Preparation of Slurry Composition for Non-Aqueous Secondary Battery Separator> A glass bottle was charged with 100 parts of alumina particle powder (LS-710 manufactured by Nippon Light Metal, average particle size 0.5 μm) as inorganic fine particles, 1.2 parts of a polycarboxylic acid-based dispersant (BYK154 manufactured by BYK-Chemie, active ingredient 42%), and 100 parts of water, followed by the addition of 80 parts of zirconia beads with a particle size of 0.8 mm. The bottle was then capped and shaken for 60 minutes using an Automatic Match Shaker SK550 1.1 manufactured by FAST&FLUID Management. The zirconia beads were then filtered off to obtain a concentrated dispersion solution of inorganic fine particles. To 201.2 parts (100 parts solids) of this inorganic microparticle dispersion solution, 0.5 parts of a leveling agent (BYK-349 manufactured by BYK-Chemie, active ingredient 100%), 0.6 parts of an antifoaming agent (BYK-018 manufactured by BYK-Chemie, active ingredient 100%), 1.5 parts of a 4.0% aqueous solution of carboxymethylcellulose (CMC Daicel #1220, manufactured by Daicel Chemical Industries, Ltd.) as a thickener, 20.0 parts (3.0 parts solids) of a resin composition for a non-aqueous secondary battery separator containing polymer (A1-1), and 13.0 parts of prepared water were added, and the mixture was mixed and stirred for 15 minutes using a disperser to prepare a slurry composition 1 for a non-aqueous secondary battery separator.

[0091] [Examples 16 to 36, Comparative Examples 5 to 8] A slurry composition for a non-aqueous secondary battery separator was prepared in the same manner as in Example 15, except that the composition and blending amounts (parts by mass) were changed to those shown in Table 3.

[0092] Evaluation of Slurry Compositions for Non-Aqueous Secondary Battery Separators The storage stability of the slurry composition for a non-aqueous secondary battery separator of the present invention was evaluated by the following method. The results are shown in Table 3.

[0093] <Storage stability> The obtained slurry composition for a nonaqueous secondary battery separator was diluted to a solids concentration of 0.5% by mass, and the average particle size of the slurry composition was measured using a laser diffraction / scattering particle size distribution analyzer (Microtrac MT3000II manufactured by Microtrac Bell Co., Ltd.).Furthermore, the viscosity (initial) of the slurry composition for a nonaqueous secondary battery separator was measured using a stress-controlled rheometer (AR-2000 manufactured by TA Instruments Co., Ltd.) under conditions of 25°C and 2.0 rad / s. Furthermore, the slurry composition was stored at 50°C for 60 days, and then redispersed by stirring for 15 minutes with a disperser. The average particle size and viscosity (after storage) of the slurry composition were measured in the same manner as before storage (initial). The rate of change in the average particle size and viscosity before and after high-temperature storage was calculated using the following formula. Change in average particle size [%] = Average particle diameter (after storage) / [average particle diameter (after storage) - average particle diameter (initial)] × 100 Viscosity change rate [%] = viscosity (after storage) / [viscosity (initial) - viscosity (after storage)] × 100 [Evaluation criteria] S: The rate of change in average particle size is less than 10%, and the rate of change in viscosity is also less than 10%. (Very good) A: Either the rate of change in average particle size is 10% or more and less than 50%, and the rate of change in viscosity is less than 10%, or the rate of change in average particle size is less than 10%, and the rate of change in viscosity is 10% or more and less than 40%. (Good) B: The rate of change in average particle size is 10% or more and less than 50%, and the rate of change in viscosity is 10% or more and less than 40%. (Available for use) C: The change in average particle size is 50% or more, or the change in viscosity is 40% or more. (Unavailable)

[0094] [Table 3]

[0095] [Example 37] <Preparation of separator for non-aqueous secondary battery> The nonaqueous secondary battery separator slurry composition 1 prepared in Example 15 was applied to one side of a porous polyethylene substrate (film thickness 8.0 μm) using a bar coater to a dry film thickness of 3.0 μm. After application, the coating was dried in an oven at 80°C for 1 minute to obtain a nonaqueous secondary battery separator (initial). The above slurry composition 1 was then allowed to stand at 50°C for 60 days, after which it was stirred with a disperser for 15 minutes to be redispersed. This slurry composition was used for coating and drying in the same manner as above to obtain a nonaqueous secondary battery separator (after storage).

[0096] (Preparation of negative electrode) As negative electrode active materials, 88.2 parts of natural graphite, 9.8 parts of SiO, and 66.7 parts of a 1.5% aqueous solution of carboxymethyl cellulose (CMC Daicel #1190, manufactured by Daicel Chemical Industries, Ltd.) (1 part by mass as solids) were kneaded in a planetary mixer, and then 33 parts of water and 2.22 parts of a polymer (A2-1) dispersion (1.0 part as solids) were mixed to obtain a slurry composition for a lithium secondary battery negative electrode. This slurry composition was applied using a doctor blade to a 20 μm thick copper foil that served as a current collector, and then heated and dried at 80 ° C. to obtain a coating weight per unit area of ​​the electrode of 9 mg / cm. 2 Further, a rolling treatment was carried out using a roll press, and the density of the composite layer was adjusted to 1.6 g / cm 3 A negative electrode having the following structure was fabricated.

[0097] (Preparation of positive electrode) LiNi as the positive electrode active material 0.5 Mn 0.3 Co 0.2A slurry composition for a secondary battery positive electrode was prepared by mixing 92 parts by weight of 02, 4 parts by weight of acetylene black (Denka Black HS-100, Denka Co., Ltd.) as a conductive agent, 80 parts by weight (2 parts by weight as solids) of a 2.5% by weight aqueous solution of carboxymethyl cellulose (CMC Daicel #1240, Daicel Chemical Industries, Ltd.) as a binder, 3.3 parts by weight (2 parts by weight as solids) of a polytetrafluoroethylene aqueous dispersion (30-J, 60% solids aqueous dispersion, DuPont-Mitsui Fluorochemicals Co., Ltd.) in a mixer, and 25 parts by weight of water. This slurry composition was applied using a doctor blade to a 20 μm-thick aluminum foil current collector and then dried by heating at 120°C to obtain an electrode with a coating weight per unit area of ​​20 mg / cm. 2 Further, a rolling treatment was carried out using a roll press, and the density of the composite layer was adjusted to 3.1 g / cm. 3 A positive electrode having the following structure was fabricated.

[0098] <Fabrication of a Lithium-Ion Non-Aqueous Secondary Battery> The positive and negative electrodes were punched out to 45 mm x 40 mm and 50 mm x 45 mm, respectively. The positive and negative electrodes were placed facing each other with a protective layer separator in between, and inserted into an aluminum laminate bag. After vacuum drying, an electrolyte (a non-aqueous electrolyte prepared by dissolving LiPF6 at a concentration of 1 M in a mixed solvent of ethylene carbonate and diethyl carbonate in a 1:1 (volume ratio) mixture) was poured into the bag, and the aluminum laminate was sealed to produce a laminate-type non-aqueous secondary battery. The lithium ion type battery was fabricated in a glove box purged with argon gas, and a lithium ion type non-aqueous secondary battery was fabricated.

[0099] [Examples 38 to 62, Comparative Examples 9 to 12] A non-aqueous secondary battery separator and a non-aqueous secondary battery were produced in the same manner as in Example 37, except that the slurry composition or thickness of the protective layer was changed to those shown in Table 4.

[0100] The obtained non-aqueous secondary battery separator was used to evaluate heat resistance, adhesion, and abrasion resistance, and the non-aqueous secondary battery was used to evaluate rate characteristics and high-temperature cycle characteristics by the following methods. The results are shown in Table 4.

[0101] <Separator evaluation> <Heat resistance> The obtained nonaqueous secondary battery separator was cut into a square measuring 6 cm wide x 6 cm long to prepare a test specimen. This test specimen was sandwiched between three sheets of high-quality paper and placed in an oven at 150°C for one hour. The paper holding the test specimen was then removed from the oven, and the length of the test specimen was measured in both the MD (machine direction) and TD (transverse direction), and the area of ​​the test specimen was calculated. The thermal shrinkage of the separator was then calculated using the following formula from the change in area before and after the heat resistance test. A smaller thermal shrinkage indicates better heat resistance of the separator. Sample area [mm 2 ] = (MD length of sample) × (TD length of sample) Heat shrinkage rate [%]: = [(sample area after heating) / (sample area before heating)] x 100 [Evaluation criteria] S: The heat shrinkage rate is less than 1%. (Very good) A: The heat shrinkage rate is 1% or more and less than 3%. (Good) B: The thermal shrinkage rate is 3% or more and less than 5%. (Available for use) C: The heat shrinkage rate is 5% or more. (Unavailable)

[0102] <Adhesion> The obtained non-aqueous secondary battery separator was cut into a rectangular shape measuring 200 mm in length and 20 mm in width to prepare a test specimen. Cellophane tape (18 mm wide) specified in "JIS Z1522" was attached to the protective layer side of the cut-out test specimen along the length of the specimen. One end of the separator was then pulled in a 180° direction at a pulling rate of 10 mm / min to measure the stress (peel strength) when peeled off. A higher peel strength indicates better adhesion of the protective layer in the separator. [Evaluation criteria] S: Peel strength is 100 N / m or more. (Very good) A: Peel strength is 50N / m or more and less than 100N / m. (Good) B: Peel strength is 25 N / m or more and less than 50 N / m. (Available for use) C: Peel strength is less than 25 N / mm. (Unavailable)

[0103] <Abrasion resistance> The protective layer of the obtained non-aqueous secondary battery separator was rubbed with the pad of a finger 40 times in a rectangular area 20 mm long and 10 mm wide to evaluate the abrasion resistance of the protective layer. The smaller the area of ​​the peeled part, the better the abrasion resistance. [Evaluation criteria] S: Peeled area is less than 1% based on the total rubbed area. (Very good) A: Based on the total rubbed area, the peeled area is 1% or more but less than 3%. (Good) B: Peeled area is 3% or more but less than 5% of the total rubbed area. (Available for use) C: Peeled area is 5% or more based on the total rubbed area. (Unavailable)

[0104] Evaluation of non-aqueous secondary batteries <Rate characteristics> The resulting lithium-ion nonaqueous secondary battery was subjected to charge / discharge measurements using a charge / discharge device (SM-8 manufactured by Hokuto Denko Corporation). It was charged at a constant current and constant voltage at a charge current of 0.2 C up to a charge cut-off voltage of 4.2 V, and then discharged at constant currents of 0.2 C and 2 C until the discharge cut-off voltage reached 3.0 V, and the discharge capacities were calculated for each. The rate characteristics were calculated using the following formula as the ratio of the 0.2 C discharge capacity to the 2 C discharge capacity. The higher the value, the better the rate characteristics. Rate characteristic [%] = 2C discharge capacity / 0.2C discharge capacity × 100 [Evaluation criteria] S: Rate characteristics are 85% or more. (Very good) A: Rate characteristics are 80% or more and less than 85%. (Good) B: The rate characteristic is 75% or more and less than 80%. (Available for use) C: Rate characteristics are less than 75%. (Unavailable)

[0105] <High-temperature cycle characteristics> The obtained lithium ion type nonaqueous secondary battery was charged at a constant current and constant voltage in a 48°C thermostatic chamber at a charge current of 1 C until the end-of-charge voltage reached 4.2 V, and then discharged at a constant current of 1 C until the end-of-discharge voltage reached 3.0 V, to determine the initial discharge capacity. This charge / discharge cycle was repeated 300 times, and the discharge capacity retention rate (the percentage of the 300th discharge capacity relative to the initial discharge capacity) was calculated. A higher discharge capacity retention rate indicates better high-temperature cycle characteristics. [Evaluation criteria] S: The discharge capacity retention rate is 90% or more. (Very good) A: The discharge capacity retention rate is 85% or more and less than 90%. (Good) B: The discharge capacity retention rate is 80% or more and less than 85%. (Available for use) C: The discharge capacity retention rate is less than 80%. (Unavailable)

[0106] [Table 4]

[0107] As can be seen from Tables 3 and 4, the nonaqueous secondary battery separator slurry compositions (Examples 15 to 36) using the nonaqueous secondary battery separator resin compositions of Examples 1 to 14 were found to have excellent storage stability. Furthermore, the nonaqueous secondary battery separators (Examples 37 to 62) prepared by applying the slurry compositions initially and after storage at high temperatures and then redispersing them exhibited excellent heat resistance, adhesion, and abrasion resistance. Furthermore, the battery characteristics of the nonaqueous secondary batteries (Examples 37 to 62) incorporating these separators were also very good, fully satisfying the standards for practical use. On the other hand, the slurry compositions of Comparative Examples 5, 7, and 8, which used the nonaqueous secondary battery separator resin compositions of Comparative Examples 1, 3, and 4, had poor storage stability, and the separators and nonaqueous secondary batteries made therefrom were poor in various performance characteristics, particularly after high-temperature storage. Furthermore, in Comparative Example 6, the storage stability of the slurry composition of Comparative Example 2 was barely at a practical level, but the various physical properties of the separators and nonaqueous secondary batteries made therefrom were significantly poor.

[0108] That is, it was found that a slurry composition for a non-aqueous secondary battery separator using the resin composition for a non-aqueous secondary battery separator of the present invention has excellent storage stability. Furthermore, not only was the initial heat resistance, adhesion, and abrasion resistance excellent, but also a non-aqueous secondary battery separator fabricated by applying the slurry composition redispersed after long-term storage at high temperatures exhibited excellent heat resistance, adhesion, and abrasion resistance. Furthermore, the battery characteristics of a non-aqueous secondary battery comprising this separator were also excellent both initially and after storage, fully satisfying the standards for practical use. This confirms that the slurry composition for a nonaqueous secondary battery separator of the present invention suppresses aggregation of polymers and inorganic fine particles even after long-term storage at high temperatures, and that a separator produced from the slurry composition stored under high-temperature conditions exhibits good heat resistance, adhesion, and coating resistance similar to those at the initial stage of production, and can maintain good battery characteristics.

Claims

1. A resin composition for a non-aqueous secondary battery separator, comprising a polymer (A1) and an aqueous medium, wherein the polymer (A1) is a polymer of an ethylenically unsaturated monomer mixture containing 40.0 to 99.8 mass% of an ethylenically unsaturated monomer (a-1) having an amide group, and 0.2 to 60.0 mass% of an ethylenically unsaturated monomer (a-2) having a hydrophilic group and at least one functional group selected from the group consisting of an alkyl group having 8 or more carbon atoms, a styrenated phenyl group, and an alkylene oxide group having 3 or more carbon atoms, based on the total mass of the ethylenically unsaturated monomer mixture, wherein the ethylenically unsaturated monomer (a-2) comprises at least one ethylenically unsaturated monomer selected from the group consisting of: General formula (1) 【Chemical 1】 (In general formula (1), R represents an alkyl group having 8 to 16 carbon atoms, X 1 represents an ethylene oxide group having an average number of moles added of 10 to 50, and Y 1 represents a hydrogen atom or a sulfonate group.) General formula (2) 【Chemistry 2】 (In general formula (2), R represents an alkyl group having 8 to 16 carbon atoms, X 2 represents an ethylene oxide group having an average number of moles added of 10 to 50, and Y 2 represents a hydrogen atom or a sulfonate group.) General formula (3) 【Chemistry 3】 (In general formula (3), X 3 represents an alkylene oxide group having 3 or more carbon atoms and an average number of added moles of 3 to 20, Y 3 represents an ethylene oxide group having an average number of added moles of 10 to 50, and Z represents a hydrogen atom or a sulfonate group.) General formula (4) 【Chemistry 4】 (In general formula (4), m is an integer of 1 to 4, X 4 is an ethylene oxide group having an average added mole number of 10 to 50, and Y 4 is a hydrogen atom or a sulfonate group.)

2. A resin composition for a non-aqueous secondary battery separator, comprising a polymer (A1) and an aqueous medium, wherein the polymer (A1) is a polymer of an ethylenically unsaturated monomer mixture containing 40.0 to 99.8 mass% of an ethylenically unsaturated monomer (a-1) having an amide group, and 0.2 to 60.0 mass% of an ethylenically unsaturated monomer (a-2) having at least one functional group selected from the group consisting of an alkyl group having 8 or more carbon atoms, a styrenated phenyl group, and an alkylene oxide group having 3 or more carbon atoms, and a hydrophilic group, based on the total mass of the ethylenically unsaturated monomer mixture, wherein the polymer (A1) has an acid value of 0 to 50 mgKOH / g.

3. 3. The resin composition for a non-aqueous secondary battery separator according to claim 1, wherein the ethylenically unsaturated monomer (a-1) having an amide group includes (meth)acrylamide.

4. 4. The resin composition for a nonaqueous secondary battery separator according to claim 1, wherein the polymer (A1) is a particulate polymer, and the average particle size of the resin composition at a solid content concentration of 1 mass % is 10 to 5,000 nm.

5. 5. The resin composition for a non-aqueous secondary battery separator according to claim 1, wherein the polymer (A1) has a glass transition temperature in the range of 80 to 200°C.

6. A slurry composition for a non-aqueous secondary battery separator, comprising inorganic fine particles and the resin composition for a non-aqueous secondary battery separator according to any one of claims 1 to 5.

7. A slurry composition for a non-aqueous secondary battery separator, comprising inorganic fine particles and a resin composition for a non-aqueous secondary battery separator, wherein the resin composition for a non-aqueous secondary battery separator comprises a polymer (A1) and an aqueous medium, wherein the polymer (A1) is a polymer of an ethylenically unsaturated monomer mixture containing 40.0 to 99.8 mass% of an ethylenically unsaturated monomer (a-1) having an amide group, and 0.2 to 60.0 mass% of an ethylenically unsaturated monomer (a-2) having at least one functional group selected from the group consisting of an alkyl group having 8 or more carbon atoms, a styrenated phenyl group, and an alkylene oxide group having 3 or more carbon atoms, and a hydrophilic group, based on the total mass of the ethylenically unsaturated monomer mixture, and wherein the slurry composition for a non-aqueous secondary battery separator comprises 0.5 to 4.0 parts by mass of the polymer (A1) per 100 parts by mass of the inorganic fine particles.

8. A slurry composition for a non-aqueous secondary battery separator, comprising inorganic fine particles and a resin composition for a non-aqueous secondary battery separator, wherein the resin composition for a non-aqueous secondary battery separator comprises a polymer (A1) and an aqueous medium, wherein the polymer (A1) contains 40.0 to 99.8 mass% of an ethylenically unsaturated monomer (a-1) having an amide group, based on the total mass of the ethylenically unsaturated monomer mixture, and a methyl group selected from the group consisting of an alkyl group having 8 or more carbon atoms, a styrenated phenyl group, and an alkylene oxide group having 3 or more carbon atoms. and a hydrophilic group, and the slurry composition further contains a polymer (A2) (excluding the polymer (A1)), the polymer (A2) being a particulate polymer having a glass transition temperature of -40 to 40°C, and the amount of the polymer (A2) is 5.0 to 320.0 parts by mass per 100 parts by mass of the polymer (A1).

9. 8. The slurry composition for a nonaqueous secondary battery separator according to claim 6, further comprising a polymer (A2) (excluding the polymer (A1)), wherein the polymer (A2) is a particulate polymer having a glass transition temperature of −40 to 40° C., and the amount of the polymer (A2) is 5.0 to 320.0 parts by mass per 100 parts by mass of the polymer (A1).

10. A non-aqueous secondary battery separator comprising a substrate and a protective layer formed from the slurry composition for a non-aqueous secondary battery separator according to any one of claims 6 to 9.

11. 11. The separator for a non-aqueous secondary battery in accordance with claim 10, wherein the protective layer has a thickness of 1.0 to 5.0 μm.

12. A non-aqueous secondary battery comprising the separator for non-aqueous secondary batteries according to claim 10 or 11.

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