Polymer composition for non-aqueous secondary battery, negative electrode for non-aqueous secondary battery, and non-aqueous secondary battery

Abstract

To provide a polymer composition for a nonaqueous secondary battery, which allows a superior dimensional stability and battery characteristics to be developed, a negative electrode for a nonaqueous secondary battery, and a nonaqueous secondary battery.SOLUTION: A polymer composition for a nonaqueous secondary battery comprises a polymer having a unit U1 originating from a conjugated diene monomer M1. The content of the unit U1 is 0.1 mass% or more and less than 20 mass% to 100 mass% of all the constituting units of the polymer. The polymer composition for a nonaqueous secondary battery is less than 1.3 GPa in Young's modulus. The polymer composition contains insoluble components that is 90% or more to a mix solvent of which the mass ratio of ethylene carbonate and diethyl carbonate is 1:1.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polymer composition for a non-aqueous secondary battery, a negative electrode for a non-aqueous secondary battery, and a non-aqueous secondary battery.

Background Art

[0002] Conventionally, as a method for manufacturing an electrode used in an electrochemical device such as a lithium-ion secondary battery, a liquid composition in which a binder, a thickener, etc. are added to an electrode active material is applied to the surface of a current collector and dried, whereby A method of forming an electrode layer on the current collector can be mentioned. Here, as a binder that has a high adhesive force with the metal constituting the current collector and can form an electrode layer having high flexibility, a styrene-butadiene copolymer latex is known. The binder functions to improve the adhesion between the electrode layer containing the active material and the current collector. However, the above copolymer latex may have insufficient adhesion to the current collector. When the adhesion between the electrode layer and the current collector is not sufficient, the cycle characteristics of the secondary battery tend to be impaired.

[0003] In view of the above, Patent Document 1 discloses an aqueous binder resin composition containing a binder resin and an aqueous medium, wherein the binder resin is a copolymer of an ethylenically unsaturated monomer (a), and the ethylenically unsaturated monomer (a) is 10 to 70% by mass of an ethylenically unsaturated carboxylic acid ester monomer (a1) having one ethylenically unsaturated bond, styrene (a2), 8 to 60% by mass of a diene monomer (a3) containing a conjugated diene structure, and 0.01 to 10% by mass of an ethylenically unsaturated monomer (a4) having two or more ethylenically unsaturated bonds.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the aqueous binder resin composition of Patent Document 1, a non-aqueous battery having high electrolyte resistance to carbonates and carboxylic acid esters and excellent life characteristics during charge and discharge cycles at high temperatures is obtained. On the other hand, as a result of investigations by the present inventors, it has been found that there is still room for improvement in the dimensional stability of the negative electrode for non-aqueous secondary batteries obtained using the aqueous binder resin composition. Furthermore, it has been found that there is still room for improvement in the battery characteristics of non-aqueous secondary batteries provided with negative electrodes for non-aqueous secondary batteries.

[0006] The present invention has been made in view of the problems of the above prior art, and an object thereof is to provide a polymer composition for non-aqueous secondary batteries, a negative electrode for non-aqueous secondary batteries, and a non-aqueous secondary battery that exhibit excellent dimensional stability and battery characteristics.

Means for Solving the Problems

[0007] As a result of intensive studies, the present inventors have found that a polymer composition for non-aqueous secondary batteries containing a polymer having a unit U1 derived from a conjugated diene monomer M1 and having an insoluble content in a predetermined range in an electrolyte and a predetermined composition can solve the above problems when the Young's modulus of the polymer composition for non-aqueous secondary batteries is in a predetermined range, and have completed the present invention.

[0008] That is, the present invention includes the following aspects. [1] A polymer composition for non-aqueous secondary batteries containing a polymer having a unit U1 derived from a conjugated diene monomer M1, wherein the content of the unit U1 is 0.1% by mass or more and less than 20% by mass with respect to 100% by mass of all the constituent units of the polymer, the Young's modulus of the polymer composition for non-aqueous secondary batteries is less than 1.3 GPa, and the insoluble content of the polymer in a mixed solvent having a mass ratio of ethylene carbonate to diethyl carbonate of 1:1 is 90% or more, a polymer composition for non-aqueous secondary batteries. [2] The polymer further contains a unit U2 derived from an ethylenically unsaturated carboxylic acid monomer M2, The polymer composition for non-aqueous secondary batteries according to [1], wherein the content of the unit U2 is 0.1% by mass or more and 35% by mass or less with respect to 100% by mass of all the constituent units of the polymer. [3] The polymer composition for non-aqueous secondary batteries according to [1] or [2], wherein the degree of swelling of the polymer composition for non-aqueous secondary batteries with respect to the mixed solvent is 50% or more and 200% or less. [4] The monomer M2 includes an ethylenically unsaturated monocarboxylic acid and an ethylenically unsaturated dicarboxylic acid, The polymer composition for non-aqueous secondary batteries according to any one of [1] to [3], wherein the ratio of the ethylenically unsaturated monocarboxylic acid to the ethylenically unsaturated dicarboxylic acid is 1:99 to 99:1. [5] Further containing an isothiazoline compound The polymer composition for non-aqueous secondary batteries according to any one of [1] to [4], wherein the content of the isothiazoline compound is 0.0001% by mass or more and 1.0% by mass or less with respect to 100% by mass of the polymer composition for non-secondary batteries. [6] The polymer composition for non-aqueous secondary batteries according to any one of [1] to [5], further containing an active material. [7] A negative electrode for non-aqueous secondary batteries, comprising the polymer composition for non-aqueous secondary batteries according to [6]. [8] A non-aqueous secondary battery, comprising the negative electrode for non-aqueous secondary batteries according to [7].

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a polymer composition for non-aqueous secondary batteries, a negative electrode for non-aqueous secondary batteries, and a non-aqueous secondary battery that exhibit excellent dimensional stability and battery characteristics.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention (hereinafter also referred to as "the present embodiments") will be described in detail. It should be noted that the present invention is not limited to the following present embodiments, and various modifications can be made and implemented within the scope of the gist thereof.

[0011] [Polymer Composition for Non-aqueous Secondary Battery] The polymer composition for non-aqueous secondary battery of the present embodiment is a polymer composition for non-aqueous secondary battery containing a polymer having a unit U1 derived from a conjugated diene monomer M1. With respect to 100% by mass of all the constituent units of the polymer, the content of the unit U1 is 0.1% by mass or more and less than 20% by mass, the Young's modulus of the polymer composition for non-aqueous secondary battery is less than 1.3 GPa, and the insoluble content of the polymer in a mixed solvent having a mass ratio of ethylene carbonate to diethyl carbonate of 1:1 is 90% or more. Since the polymer composition for non-aqueous secondary battery of the present embodiment is configured as described above, excellent dimensional stability and battery characteristics can be exhibited.

[0012] (Polymer) The polymer in the present embodiment has a unit U1 derived from a conjugated diene monomer M1. The polymer in the present embodiment is typically contained in the polymer composition for non-aqueous secondary battery of the present embodiment in the form of polymer particles.

[0013] (Monomer M1) The conjugated diene monomer M1 in the present embodiment is not particularly limited, and examples thereof include 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene, chloroprene, etc. These may be used alone or in combination of two or more. Among these, 1,3-butadiene is preferable.

[0014] (Content of Unit U1) In this embodiment, the content of unit U1 is 0.1% by mass or more and less than 20% by mass with respect to 100% by mass of all the constituent units of the polymer. When the content of unit U1 is 0.1% by mass or more, the binder performance is ensured and the peel strength of the electrode is good. When the content of unit U1 is less than 20% by mass, the DC resistance of the battery is low. From the same viewpoints as above, the content of unit U1 is preferably 1.0% by mass to 19.0% by mass, and more preferably 3.0% by mass to 18.0% by mass.

[0015] (Monomer M2) The polymer in this embodiment preferably further contains unit U2 derived from ethylenically unsaturated carboxylic acid monomer M2. The ethylenically unsaturated carboxylic acid monomer M2 is not particularly limited, and examples thereof include ethylenically unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, and ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, and maleic acid. These may be used alone or in combination of two or more. Among the ethylenically unsaturated dicarboxylic acids, fumaric acid and itaconic acid are preferred.

[0016] (Content of unit U2) In this embodiment, from the viewpoint of making the balance between dimensional stability and the capacity retention rate of the battery better, the content of unit U2 is preferably 0.1% by mass or more and 35.0% by mass or less, more preferably 1.0% by mass to 33.0% by mass, and still more preferably 3.0% by mass to 30.0% by mass with respect to 100% by mass of all the constituent units of the polymer.

[0017] (Ratio of ethylenically unsaturated monocarboxylic acid to ethylenically unsaturated dicarboxylic acid) From the perspective of achieving a better balance between dimensional stability and the battery capacity retention rate, in the polymer of this embodiment, monomer M2 includes an ethylenically unsaturated monocarboxylic acid and an ethylenically unsaturated dicarboxylic acid, and the ratio of the ethylenically unsaturated monocarboxylic acid to the ethylenically unsaturated dicarboxylic acid is preferably from 1:99 to 99:1. From the same perspective, the above ratio is more preferably from 2:98 to 98.5:1.5, and even more preferably from 5:95 to 98:2.

[0018] (Monomer M3) In addition to units U1 and U2, the polymer in this embodiment may contain unit U3 derived from monomer M3 copolymerizable with these. Monomer M3 is not particularly limited, and examples include aromatic vinyl compounds, (meth)acrylate compounds, vinyl cyanide compounds, etc. In this specification, the term "(meth)acrylate compound" is used to mean including both methacrylate and acrylate.

[0019] The aromatic vinyl compound is not particularly limited, and examples include styrene (also denoted as ST), α-methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, divinylbenzene, etc. These may be used alone or in combination of two or more. Among these, styrene is preferred from the perspective of the stability of the resulting polymer.

[0020] The content of the unit derived from the aromatic vinyl compound is not particularly limited, but is preferably 1% by mass or more and 60% by mass or less, more preferably 2% by mass or more and 55% by mass or less, and even more preferably 3% by mass or more and 45% by mass or less, based on 100% by mass of all the constituent units of the polymer. When the content of the aromatic vinyl compound is 1% by mass or more and 60% by mass or less, the stability of the resulting polymer tends to increase.

[0021] (Meta)acrylate compounds are not particularly limited. For example, methyl (meta)acrylate, ethyl (meta)acrylate, n-propyl (meta)acrylate, i-propyl (meta)acrylate, n-butyl (meta)acrylate, i-butyl (meta)acrylate, n-amyl (meta)acrylate, i-amyl (meta)acrylate, hexyl (meta)acrylate, 2-hexyl (meta)acrylate, octyl (meta)acrylate, i-nonyl (meta)acrylate, decyl (meta)acrylate, hydroxymethyl (meta)acrylate, 2-hydroxyethyl (meta)acrylate, 2-ethylhexyl acrylate, ethylene glycol (meta)acrylate, etc. can be mentioned. These may be used alone or in combination of two or more. Among these, from the viewpoint of the stability of the resulting polymer, methyl (meta)acrylate and 2-hydroxyethyl (meta)acrylate are preferred, and methyl methacrylate, 2-hydroxyethyl (meta)acrylate, and 2-ethylhexyl acrylate are more preferred.

[0022] (Meta)acrylate compounds are not particularly limited. For example, methyl (meta)acrylate, ethyl (meta)acrylate, n-propyl (meta)acrylate, i-propyl (meta)acrylate, n-butyl (meta)acrylate, i-butyl (meta)acrylate, n-amyl (meta)acrylate, i-amyl (meta)acrylate, hexyl (meta)acrylate, 2-hexyl (meta)acrylate, octyl (meta)acrylate, i-nonyl (meta)acrylate, decyl (meta)acrylate, hydroxymethyl (meta)acrylate, 2-hydroxyethyl (meta)acrylate, 2-ethylhexyl acrylate, ethylene glycol (meta)acrylate, etc. can be mentioned. These may be used alone or in combination of two or more. Among these, from the viewpoint of the stability of the resulting polymer, methyl (meta)acrylate and 2-hydroxyethyl (meta)acrylate are preferred, and methyl methacrylate, 2-hydroxyethyl (meta)acrylate, and 2-ethylhexyl acrylate are more preferred.

[0023] Examples of vinyl cyanide compounds include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, etc. These may be used alone or in combination of two or more. Among these, acrylonitrile is preferred from the viewpoint of the stability of the resulting polymer.

[0024] The content of the unit derived from the vinyl cyanide compound is not particularly limited, but is preferably 0.1% by mass or more and 5% by mass or less, more preferably 0.1% by mass or more and 3% by mass or less, and still more preferably 0.1% by mass or more and 1% by mass or less, based on 100% by mass of all the constituent units of the polymer. When the content of the vinyl cyanide compound is 0.1% by mass or more and 5% by mass or less, the stability of the resulting polymer tends to increase.

[0025] In addition to the above monomers, aminoalkyl esters such as aminoethyl acrylate, dimethylaminoethyl acrylate, and diethylaminoethyl acrylate; pyridines such as 2-vinylpyridine and 4-vinylpyridine; glycidyl esters such as glycidyl acrylate and glycidyl methacrylate; amides such as acrylamide (also referred to as AAm), methacrylamide, N-methylolacrylamide, glycidyl methacrylamide, and N,N-butoxymethylacrylamide; vinyl carboxylate esters such as vinyl acetate; vinyl halides such as vinyl chloride; polyfunctional vinyl monomers such as divinylbenzene, (poly)ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, allyl (meth)acrylate, and α-methylstyrene; etc. may be used as monomers. These can be used alone or in combination of two or more. As the content of the unit derived from the above, for example, it can be 0.1% by mass or more and 5% by mass or less based on 100% by mass of all the constituent units of the polymer.

[0026] Regarding the content of each unit, it can be specified by analyzing the polymer by a conventional method, or can also be specified as the charging ratio of each monomer.

[0027] (Particle size) The particle size of the polymer in this embodiment is preferably 100 nm or more and 500 nm or less. The particle size in this embodiment is the average particle size determined by the dynamic light scattering method and can be measured based on the method described in the examples below. When the particle diameter is 100 nm or more, the adhesive force tends to be maintained. When the particle diameter is 500 nm or less, the storage stability of the resulting polymer tends to be maintained. Examples of the method for adjusting the particle diameter to the range of 100 nm or more and 500 nm or less include a method of adjusting the amount of seed (for example, polystyrene latex having a particle diameter of 35 nm) particles, the amount of emulsifier, the amount of ethylenically unsaturated carboxylic acid monomer M2, and the like. The particle diameter is more preferably 110 nm or more and 480 nm, still more preferably 120 nm or more and 450 nm or less, and even more preferably 130 nm or more and 400 nm or less.

[0028] (Core-shell structure) The polymer in this embodiment may be particles composed of a single phase, or may be particles having a core-shell structure of a core part and a shell part. When the polymer in this embodiment is particles having a core-shell structure, the mass ratio of the core part is preferably 30 parts by mass or more and 90 parts by mass or less, and more preferably 35 parts by mass or more and 85 parts by mass or less with respect to 100 parts by mass in total of the core part and the shell part. When the mass ratio of the core part is 30 parts by mass or more and 90 parts by mass or less, the adhesion of the members constituting the secondary battery can be improved, peeling of the members can be suppressed, and the cycle characteristics also tend to be excellent.

[0029] (Insoluble matter in electrolyte) In this embodiment, from the viewpoint of ensuring a good capacity retention rate of the battery, the insoluble matter (hereinafter also referred to as "insoluble matter in electrolyte") of the polymer with respect to a mixed solvent having a mass ratio of ethylene carbonate to diethyl carbonate of 1:1 is 90% or more. From the same viewpoint, the insoluble matter in electrolyte is more preferably 91% or more, and still more preferably 92% or more. The insoluble matter in electrolyte can be measured based on the method described in the examples below. The insoluble content in the electrolyte tends to be low when the content per unit U1 is within the above-described range. However, for example, by adopting the preferred production method (polymerization conditions) described later or using a molecular weight regulator, etc., it can be adjusted to the above-described range.

[0030] (Electrolyte swelling degree) In the present embodiment, from the viewpoint of making the dimensional stability (rebound) better, the swelling degree with respect to the mixed solvent having a mass ratio of ethylene carbonate to diethyl carbonate of 1:1 of the polymer (hereinafter, also referred to as "electrolyte swelling degree") is preferably 50% or more and 200% or less, more preferably 100% or more and 190% or less, and still more preferably 110% or more and 180% or less. The electrolyte swelling degree can be measured based on the method described in the examples below. The electrolyte swelling degree of the polymer composition for non-aqueous secondary batteries of the present embodiment tends to match the value of the electrolyte swelling degree obtained by similarly measuring the polymer itself contained in the composition. For example, when the polymer composition for non-aqueous secondary batteries of the present embodiment further contains an isothiazoline-based compound described later and the content of the isothiazoline-based compound is 0.0001% by mass or more and 1.0% by mass or less with respect to 100% by mass of the polymer composition for non-secondary batteries, the values of both are in good agreement. Therefore, the electrolyte swelling degree of the polymer composition for non-aqueous secondary batteries of the present embodiment can also be estimated from the value of the electrolyte swelling degree obtained by subjecting the polymer in the present embodiment to the same measurement. As a method for adjusting the electrolyte swelling degree to the above-described range, for example, a method of setting the content per unit U2 to the above-described preferred range, a molecular weight regulator, etc. can be mentioned.

[0031] (Young's modulus) The Young's modulus of the polymer composition for non-aqueous secondary batteries of the present embodiment is less than 1.3 GPa. Here, the Young's modulus is an index for evaluating the flexibility of the polymer. Since the value is less than 1.3 GPa, it has excellent flexibility, good springback, and as a result, the battery performance is improved. From such a viewpoint, the Young's modulus is preferably 1.0 GPa or less, more preferably 0.9 GPa or less, and most preferably 0.8 GPa or less. The Young's modulus can be measured based on the method described in the examples below. Moreover, the Young's modulus can be adjusted to the above range by containing the above-described preferable monomer components as the constituent components of the polymer in a preferable amount, etc.

[0032] (Other components) The polymer composition for a non-aqueous secondary battery of the present embodiment further contains an isothiazoline compound, and the content of the isothiazoline compound is preferably 0.0001% by mass or more and 1.0% by mass or less with respect to 100% by mass of the polymer composition for the non-secondary battery. When the above range is satisfied, hysteresis viscosity behavior with respect to shear force can be suppressed, and more stable coatability tends to be exhibited. The isothiazoline compound is not particularly limited, and various known ones can be adopted. For example, 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 1,2-benzisothiazolin-3-one, 2-n-octyl 4-isothiazolin-3-one, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, 2-ethyl-4-isothiazolin-3-one, 4,5-dichloro-2-cyclohexyl-4-isothiazolin-3-one, 5-chloro-2-ethyl-4-isothiazolin-3-one, 5-chloro-2-t-octyl-4-isothiazolin-3-one, 4-chloro-2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-n-octyl-4-isothiazolin-3-one, N-n-butyl-1,2-benzisothiazolin-3-one, N-butylbenzisothiazolin-3-one, N-methylbenzisothiazolin-3-one, N-ethylbenzisothiazolin-3-one, N-propylbenzisothiazolin-3-one, N-isobutylbenzisothiazolin-3-one, N-pentylbenzisothiazolin-3-one, N-isopentylbenzisothiazolin-3-one, N-hexylbenzisothiazolin-3-one, N-allylbenzisothiazolin-3-one, N-(2-butenyl)benzisothiazolin-3-one, etc. can be mentioned. Among these, 2-methyl-4-isothiazolin-3-one is preferable.

[0033] [Method for Producing Polymer Composition for Non-Aqueous Secondary Battery] The polymer composition for non-aqueous secondary battery of the present embodiment is not particularly limited. For example, it can be produced by preparing a system containing the above-mentioned monomers and subjecting them to emulsion polymerization.

[0034] Appropriate seed particles can be used during emulsion polymerization, and the seed particles can also be obtained by ordinary emulsion polymerization. In addition, known methods can be adopted during emulsion polymerization, and it can be produced by appropriately using a polymerization initiator, a molecular weight regulator, a chelating agent, a pH regulator, an emulsifier, etc. in an aqueous medium.

[0035] The emulsifier is not particularly limited. For example, anionic surfactants, nonionic surfactants, amphoteric surfactants, reactive surfactants, etc. can be mentioned. These can be used alone or in combination of two or more.

[0036] The anionic surfactant is not particularly limited. For example, sulfates of higher alcohols, alkylbenzene sulfonates, aliphatic sulfonates, sulfates of polyethylene glycol alkyl ethers, etc. can be mentioned.

[0037] The nonionic surfactant is not particularly limited. For example, alkyl ester type, alkyl ether type, alkyl phenyl ether type of polyethylene glycol, etc. can be mentioned.

[0038] The amphoteric surfactant is not particularly limited. For example, betaines such as lauryl betaine and stearyl betaine, amino acid types such as lauryl-β-alanine, stearyl-β-alanine, and lauryldi(aminoethyl)glycine can be mentioned.

[0039] The reactive surfactant is not particularly limited. For example, polyoxyethylene alkyl propenyl phenyl ether, α-〔1-〔(allyloxy)methyl〕-2-(nonylphenoxy)ethyl〕-ω-hydroxypolyoxyethylene, etc. can be mentioned.

[0040] The polymerization initiator is not particularly limited. For example, water-soluble polymerization initiators such as sodium persulfate, potassium persulfate, and ammonium persulfate; oil-soluble polymerization initiators such as benzoyl peroxide and lauryl peroxide; redox polymerization initiators formed by a combination with a reducing agent, etc. can be used alone or in combination. The amount of the polymerization initiator used is preferably in the range of 0.1 to 3 parts by mass based on 100 parts by mass of the total monomers.

[0041] The molecular weight regulator is not particularly limited as long as it can be used in ordinary emulsion polymerization. For example, halogenated hydrocarbons such as chloroform and carbon tetrachloride; mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and thioglycolic acid; xanthogens such as dimethyl xanthogen disulfide and diisopropyl xanthogen disulfide; terpinolene, α-methylstyrene dimer, etc. These can be used alone or in combination. The amount of the molecular weight regulator used is preferably 0 parts by mass or more and 0.5 parts by mass or less, more preferably 0 parts by mass or more and 0.4 parts by mass or less, and still more preferably 0 parts by mass or more and 0.3 parts by mass or less, based on 100 parts by mass of the total monomers. By setting it within this range, the above-mentioned insoluble matter in the electrolyte and the electrolyte swelling degree can be set within a preferable range. Among these, α-methylstyrene dimer and t-dodecyl mercaptan are preferably used.

[0042] Examples of the polymerization method of the polymer having a core-shell structure include: 1. A method in which a polymer having a core part composition is polymerized in a separate container in advance, a predetermined amount of this polymer is added to a polymerization container as seed particles, and then monomers giving a shell part composition are polymerized; 2. A method in which a core part composition is polymerized and polymerization of monomers giving a shell part composition is carried out in the same polymerization container. In any polymerization method, the polymerization rate of the core part composition is preferably 50% by mass or more, more preferably 80% by mass or more.

[0043] As methods for charging monomers that provide polymers for the core part and the shell part, the following can be adopted: 1. A method of charging the monomer mixture all at once; 2. A method of polymerizing a part of the monomers and then continuously or intermittently adding the remainder; 3. A method of continuously or intermittently adding the monomer mixture from the start of polymerization, etc. Also, these methods can be combined.

[0044] Regarding conditions such as the stirring speed, polymerization temperature, reaction (polymerization) time, etc. during production, as long as the polymer composition for non-aqueous secondary batteries of this embodiment can be obtained, they are not particularly limited. Typically, the stirring speed can usually be 50 rpm or more and 500 rpm or less, the reaction time can usually be 3 hours or more and 72 hours or less, and the polymerization temperature can usually be 65°C or more and 100°C or less. More preferably, it is 70°C or more and 100°C or less, and even more preferably 75°C or more and 100°C or less. By setting the polymerization temperature within the above range, there is a tendency to favorably promote the cross-linking reaction of the conjugated diene monomer M1, and the insoluble matter in the electrolytic solution can be adjusted within the above-mentioned range. The same applies to the case having a core-shell structure with respect to conditions such as the stirring speed, polymerization temperature, reaction (polymerization) time, etc.

[0045] In the production method of this embodiment, after obtaining the polymer as described above, if necessary, the polymer is dispersed in a dispersion medium and optional components are added to obtain the polymer composition for non-aqueous secondary batteries of this embodiment. Water can be used as the dispersion medium, and an organic solvent suitable for the active material can also be used if necessary.

[0046] [Use of the Polymer Composition for Non-Aqueous Secondary Batteries] The polymer composition for non-aqueous secondary batteries of this embodiment can contain various known optional components in addition to the polymers in this embodiment, depending on its use. The use of the polymer composition for non-aqueous secondary batteries of this embodiment is not particularly limited as long as it is used as a material for non-aqueous secondary batteries, and it can be used as a material for the negative electrode, a material for the positive electrode, a material for the separator, etc., but it is particularly preferably used as a material for the negative electrode.

[0047] Hereinafter, when the polymer composition for a non-aqueous secondary battery of the present embodiment is used for manufacturing a negative electrode, a positive electrode, or a separator, it shall be particularly referred to as a "composition for manufacturing battery materials". Here, when manufacturing a negative electrode with the composition for manufacturing battery materials, the composition for manufacturing battery materials can include the polymer in the present embodiment, a negative electrode active material, and optional components as necessary. Further, when manufacturing a positive electrode with the composition for manufacturing battery materials, the composition for manufacturing battery materials can include the polymer in the present embodiment, a positive electrode active material, and optional components as necessary. That is, it can be said that the composition for manufacturing battery materials includes the polymer in the present embodiment and an active material. Furthermore, when manufacturing a separator with the composition for manufacturing battery materials, the composition for manufacturing battery materials can include the polymer particles in the present embodiment, a separator raw material, and optional components as necessary. When the polymer composition for a non-aqueous secondary battery of the present embodiment does not contain any of a negative electrode active material, a positive electrode active material, and a separator raw material, it can be applied as an additive for manufacturing battery materials. That is, when the composition of the present embodiment is used for binder applications, it is referred to as a "composition for binder", and when used for thickener applications, it is referred to as a "composition for thickener", respectively. As described above, the term "polymer composition for a non-aqueous secondary battery of the present embodiment" can be said to include a "composition for manufacturing battery materials", a "composition for binder", and a "composition for thickener", and is common in that the polymer in the present embodiment is included in any application. Further, in any application, when the polymer composition for a non-aqueous secondary battery of the present embodiment contains optional components, the types, blending ratios, etc. thereof are not particularly limited and may be appropriately determined according to the application.

[0048] A non-aqueous secondary battery negative electrode can be manufactured with the composition for manufacturing battery materials. In other words, it can be said that the non-aqueous secondary battery negative electrode of the present embodiment includes the polymer composition for a non-aqueous secondary battery of the present embodiment. When manufacturing a negative electrode with the composition for manufacturing battery materials, the negative electrode active material that can be used is not particularly limited, and examples thereof include carbon-based active materials and silicon-based active materials. The carbon-based active material is not particularly limited, and examples thereof include graphite, carbon fiber, coke, hard carbon, mesocarbon microbeads (MCMB), fired product of furfuryl alcohol resin (PFA), conductive polymer (poly-p-phenylene, etc.). The silicon-based active material is not particularly limited, and examples thereof include silicon, SiO x (0.01 ≦ x < 2), an alloy of silicon and a transition metal, etc.

[0049] When manufacturing a positive electrode with the composition for manufacturing a battery material, the positive electrode active material that can be used is not particularly limited, and examples thereof include lithium-containing composite oxides, transition metal oxides, transition metal fluorides, transition metal sulfides, etc. The lithium-containing composite oxide is not particularly limited, and examples thereof include LiCoO2, LiMnO2, LiNiO2, LiMn2O4, LiXCoYSnZO2, LiFePO4, LiXCoYSnZO2, etc. The transition metal oxide is not particularly limited, and examples thereof include MnO2, MoO3, V2O5, V6O 13 , Fe2O3, Fe3O4, etc. The transition metal fluoride is not particularly limited, and examples thereof include CuF2, NiF2, etc. The transition metal sulfide is not particularly limited, and examples thereof include TiS2, TiS3, MoS3, FeS2, etc.

[0050] In addition, the binder composition of the present embodiment can contain an antifoaming agent as an optional component. Examples of the antifoaming agent include various antifoaming agents of mineral oil type, silicone type, acrylic type, and polyether type. When containing an antifoaming agent, it tends to be more excellent in defoaming property. In this case, the type and blending ratio of the optional components are not particularly limited.

[0051] In the present embodiment, from the viewpoint of defoaming property, the thickener composition preferably contains the polymer, the preservative, and the antifoaming agent in the present embodiment. The isothiazoline compounds described above can function as preservatives. As preservatives other than the isothiazoline compounds, phenols and their alkali metal salts, quinone chlorides, nitro group-containing compounds, amines, amides, iodine-containing compounds, thiazoles, thiocyanates, etc. can be mentioned.

[0052] [Non-aqueous secondary battery] The non-aqueous secondary battery of this embodiment can be manufactured using the polymer composition for non-aqueous secondary batteries of this embodiment. In other words, the non-aqueous secondary battery of this embodiment includes the polymer composition for non-aqueous secondary batteries of this embodiment, and preferably includes the negative electrode for non-aqueous secondary batteries of this embodiment. When the non-aqueous secondary battery of this embodiment is a lithium-ion secondary battery, typical constituent members thereof include a negative electrode, a negative electrode current collector, a positive electrode, a positive electrode current collector, a separator, and an electrolytic solution. In the non-aqueous secondary battery of this embodiment, at least one of its main members (negative electrode, positive electrode, and separator) is obtained using the polymer composition for non-aqueous secondary batteries of this embodiment, that is, it is sufficient that at least one of its main members includes the polymer composition for non-aqueous secondary batteries of this embodiment. Regarding whether each member includes the polymer composition for non-aqueous secondary batteries of this embodiment, it can be specified by whether the polymer particles in this embodiment are included in the member.

[0053] [Method for manufacturing non-aqueous secondary battery] Although the manufacturing method of the non-aqueous secondary battery of this embodiment is not particularly limited, taking a lithium-ion secondary battery as an example, the polymer composition for the non-aqueous secondary battery of this embodiment is applied to a current collector, heated, and dried to form a corresponding electrode. Examples include opposing the positive electrode and the negative electrode via a separator, injecting an electrolytic solution, and sealing it. The negative current collector is not particularly limited, but for example, a copper foil is used. The positive current collector is not particularly limited, but for example, an aluminum foil is used. The electrolytic solution is not particularly limited, but for example, a solution in which electrolytes such as LiClO4, LiBF4, and LiPF6 are dissolved in an organic solvent can be used. The organic solvent is not particularly limited, and examples include ethers, ketones, lactones, nitriles, amines, amides, carbonates, chlorinated hydrocarbons, etc. Representative examples include tetrahydrofuran, acetonitrile, butyronitrile, propylene carbonate, ethylene carbonate, diethyl carbonate, etc., and it is used as a single type or a mixture of two or more types.

[0054] The coating method is not particularly limited, and for example, any coater head such as a reverse roll coater, comma bar coater, gravure coater, air-knife coater, etc. can be used. The drying method is also not particularly limited, and for example, natural drying, blowing drying, warm air drying, infrared heater, far-infrared overheater, etc. can be used. The drying temperature is not particularly limited, but for example, it can be carried out at 60°C to 150°C.

Examples

[0055] The following examples are given to more specifically explain this embodiment, but this embodiment is not limited by these examples in any way.

[0056] [Example 1] To the reactor, 130 parts by mass of ion-exchanged water, 3.0 parts by mass of itaconic acid (hereinafter also referred to as "IA" as a monomer component), 1.0 part by mass of fumaric acid (hereinafter also referred to as "FA" as a monomer component), 0.1 part by mass of polystyrene latex with a particle diameter of 35 nm as a seed, and 0.1 part by mass of sodium alkyl diphenyl ether sulfonate as an emulsifier were added, and the temperature was raised to 85 °C while stirring and maintained. Next, 14 parts by mass of butadiene (hereinafter also referred to as "BD" as a monomer component), 19 parts by mass of styrene (hereinafter also referred to as "ST" as a monomer component), 0.4 part by mass of methyl methacrylate (hereinafter also referred to as "MMA" as a monomer component), 0.4 part by mass of acrylonitrile (hereinafter also referred to as "AN" as a monomer component), 50 parts by mass of 2-ethylhexyl acrylate (hereinafter also referred to as "2-EHA" as a monomer component), 2 parts by mass of 2-hydroxyethyl acrylate (hereinafter also referred to as "HEA" as a monomer component), 0.1 part by mass of α-methylstyrene dimer (hereinafter also referred to as "α-MSD" as a molecular weight regulator), 0.05 part by mass of t-dodecyl mercaptan (hereinafter also referred to as "t-DDM" as a molecular weight regulator), 0.2 part by mass of acrylic acid (hereinafter also referred to as "AA" as a monomer component), and 10 parts by mass of methacrylic acid (hereinafter also referred to as "MAA" as a monomer component) were added dropwise over 6 hours. Ten minutes after the addition of the above monomer components started, 20 parts by mass of ion-exchanged water, 1.0 part by mass of sodium persulfate, 0.03 part by mass of caustic soda, and 0.1 part by mass of sodium alkyl diphenyl ether sulfonate as an emulsifier were added dropwise over 7 hours. After the addition was completed, the temperature was raised to 95 °C and reacted for 1 hour to complete the polymerization. The obtained reaction solution was subjected to steam distillation to remove unreacted monomers, and the obtained polymer was adjusted to pH 6.5 with sodium hydroxide. Here, 0.05 part by mass of 2-methyl-4-isothiazolin-3-one was added based on 100 parts by mass of the polymer, and then filtration was performed using a 200 μm mesh. The particle diameter of the polymer in the composition obtained by the above operation was 205 nm. Also, the solid content (polymer) of the composition was 40%.

[0057] [Examples 2, 3, 5, 6, 9 and Comparative Examples 2 to 4] In each example, a composition containing a polymer was prepared in the same manner as in Example 1, except that the blending amounts of the monomer components in Example 1 were changed as shown in Table 1. Note that the blanks in the table mean that the corresponding monomer components were not blended. Also, in Comparative Example 1, 8.5 parts by mass of butyl acrylate (hereinafter also referred to as "BA" as a monomer component) was used.

[0058] [Examples 4, 7] In each example, a composition containing a polymer was prepared in the same manner as in Example 1, except that the blending amounts of the monomer components in Example 1 were changed as shown in Table 1, and the amount of ion-exchanged water charged into the reactor was changed from 130 parts by mass to 330 parts by mass. Also, the solid content (polymer) of the composition was 20%.

[0059] [Example 8] A composition containing a polymer was prepared in the same manner as in Example 1, except that the blending amounts of the monomer components in Example 1 were changed as shown in Table 1, and the amount of polystyrene latex with a particle diameter of 35 nm as a seed charged into the reactor was changed from 0.1 part by mass to 0.6 part by mass. Also, the solid content (polymer) of the composition was 40%.

[0060] [Example 10] To the reactor, 130 parts by mass of ion-exchanged water, 1.0 part by mass of itaconic acid, 1.0 part by mass of fumaric acid, 0.1 part by mass of polystyrene latex with a particle diameter of 35 nm as a seed, and 0.1 part by mass of sodium alkyl diphenyl ether sulfonate as an emulsifier were added, and the temperature was raised to 85 °C and held while stirring. Here, as components constituting the core part of the polymer, 8.4 parts by mass of butadiene, 17.8 parts by mass of styrene, 0.24 part by mass of methyl methacrylate, 0.24 part by mass of acrylonitrile, 30 parts by mass of 2-ethylhexyl acrylate, 1.2 parts by mass of 2-hydroxyethyl acrylate, 0.05 part by mass of α-methylstyrene dimer, and 0.1 part by mass of t-dodecyl mercaptan were added over 3 hours. Ten minutes after the addition of the above monomer components began, 20 parts by mass of ion-exchanged water, 1.0 part by mass of sodium persulfate, 0.03 part by mass of sodium hydroxide, and 0.1 part by mass of an aliphatic sulfonate as an emulsifier were added over 7 hours. After completion of the addition, the reaction was carried out for 1 hour. As components constituting the shell portion of the polymer, 5.6 parts by mass of butadiene, 3.2 parts by mass of styrene, 0.16 part by mass of methyl methacrylate, 0.16 part by mass of acrylonitrile, 20 parts by mass of 2-ethylhexyl acrylate, 0.8 part by mass of 2-hydroxyethyl acrylate, 0.08 part by mass of acrylic acid, 10 parts by mass of methacrylic acid, and 0.005 part by mass of α-methylstyrene dimer were added over 2 hours. At the same time, 20 parts by mass of ion-exchanged water, 1.0 part by mass of sodium persulfate, 0.03 part by mass of sodium hydroxide, and 0.1 part by mass of an aliphatic sulfonate as an emulsifier were also added during the addition of the second-stage composition. After completion of the addition, the temperature was raised to 95 °C and the reaction was carried out for 1 hour to complete the polymerization. The obtained reaction solution was subjected to steam distillation to remove unreacted monomers, and the obtained polymer was adjusted to pH 6.5 with sodium hydroxide. Here, 0.05 part by mass of 2-methyl-4-isothiazolin-3-one was added based on 100 parts by mass of the polymer, and then filtration was performed using a 200 μm mesh. The particle diameter of the polymer in the composition obtained by the above operation was 210 nm. Also, the solid content (polymer) of the composition was 40%.

[0061] [Example 11] A composition containing a polymer was prepared in the same manner as in Example 1, except that the blending amounts of the monomer components in Example 10 were changed as shown in Table 1. The blanks in the table mean that the corresponding monomer components were not blended.

[0062] [Comparative Example 1] A composition containing a polymer was prepared in the same manner as in Example 3 of JP-A-2018-198199.

[0063] [Preparation of Coating Liquid for Negative Electrode of Secondary Battery] 100 parts by mass of natural graphite as the negative electrode active material and 1.0 part by mass of carboxymethyl cellulose as the thickener were placed in a planetary mixer (manufactured by Primix Corporation) and stirred at 40 rpm for 10 minutes, and then stirred at 60 rpm for 20 minutes. Furthermore, 0.4 part by mass of carboxymethyl cellulose was added and stirred at 40 rpm for 20 minutes. Then, 1.5 parts by mass of the composition obtained in each example and ion-exchanged water were added so that the solid content became 55%, and stirred at 40 rpm for 10 minutes to obtain a coating liquid for the negative electrode of a secondary battery.

[0064] <Fabrication of Negative Electrode of Secondary Battery> Using the above coating liquid, it was applied to one side of a copper foil with a die coater so that the thickness after drying became 100 μm, and then dried at 60 °C for 60 minutes. After drying at 120 °C for 3 minutes, it was compression-molded with a roll press to obtain a negative electrode of a secondary battery. The coating amount of the negative electrode active material was 106 g / m 2 , and the bulk density of the negative electrode active material was 1.35 g / cm 3 was adjusted.

[0065] <Fabrication of Secondary Battery> The positive electrode and negative electrode of the secondary battery were punched into a circular shape, and after laminating the positive electrode, separator, and negative electrode in this order so that the active material surfaces of the positive electrode and negative electrode faced each other, they were housed in a stainless steel container with a lid. The container and the lid were insulated, and the container was arranged to be in contact with the copper foil of the negative electrode and the lid was arranged to be in contact with the aluminum foil of the positive electrode. Then, an electrolytic solution was injected into this container and sealed, and left at room temperature for 1 day in this state to fabricate a secondary battery. The electrolytic solution used here was prepared by dissolving LiPF6 as a solute in a mixed solvent of ethylene carbonate / ethyl methyl carbonate = 1 / 2 (volume ratio) so that the concentration became 1.0 mol / L. In addition, a polyethylene porous membrane was used as the separator, and the negative electrodes of the secondary battery obtained in Examples 1 to 11 and Comparative Examples 1 to 5 were used as the negative electrodes of the secondary battery. Furthermore, the positive electrode of the secondary battery used was fabricated as follows. As the positive electrode active material, 92.2 mass% of lithium cobalt composite oxide (LiCoO2), 2.3 mass% each of flaky graphite and acetylene black as conductive materials, and 3.2 mass% of polyvinylidene fluoride (PVDF) as a binder were dispersed in N-methylpyrrolidone (NMP) to prepare a slurry. This slurry was applied to one side of an aluminum foil with a thickness of 20 μm serving as a positive electrode current collector using a die coater, dried at 130 °C for 3 minutes, and then compression-molded with a roll press machine. At this time, the coating amount of the active material of the positive electrode was 250 g / m 2 , and the tap density of the active material was set to 3.00 g / cm 3 . The electrode thus obtained was used as a secondary battery positive electrode.

[0066] (Average particle diameter) The average particle diameter of the polymer obtained in each example was measured using a particle size measuring device (Microtrac UPA150, manufactured by Nikkiso Co., Ltd.). The measurement conditions were a loading index = 0.15 to 0.3 and a measurement time of 300 seconds, and the value of the 50% particle diameter in the obtained data was taken as the average particle diameter by the dynamic light scattering method.

[0067] (Electrolyte-insoluble content and electrolyte swelling degree) The composition obtained in each example was left standing in an oven at 130 °C for 1 hour to be dried. The polymer film obtained by drying was cut out to a mass of about 0.5 g, and this was used as a sample to measure the mass (Wa; unit: g). This sample was placed in a 50 mL vial together with 10 g of a mixed solvent of ethylene carbonate:diethyl carbonate = 1:1 (mass ratio), and after allowing the mixed solvent to penetrate at 60 °C for 1 day, the sample was taken out, washed with the above mixed solvent, and the mass (Wb: g) was measured in a wet state. Then, the sample was left standing in an oven at 150 °C for 1 hour and then the mass was measured (Wc: g), and the insoluble content and swelling degree of the copolymer with respect to the electrolyte were calculated from the following formula. Insoluble content of the polymer with respect to the electrolyte (%) = (Wc) ÷ (Wa) × 100 Swelling degree of the polymer with respect to the electrolyte (%) = (Wb) ÷ (Wc) × 100

[0068] (Young's modulus) The compositions obtained in each example were applied to a substrate to a thickness of about 500 μm (appropriately adjusted according to the solid content) and dried. In this way, a film adjusted to a thickness of 200 μm was obtained as a sample. This sample was pushed in with a load of 100 mN / 20 s using a microhardness tester and then held for 5 s. Further, unloading was performed under the same conditions as the load increase, and the indentation depth was evaluated. The Young's modulus was calculated from the obtained load-displacement curve.

[0069] (Input / output characteristics) After adjusting the secondary battery obtained in each example to SOC 50%, (i) charging was performed at 0.1C for 10 s, followed by a 10-minute rest, discharging was performed at 0.1C for 10 s, and then a 10-minute rest, (ii) charging was performed at 0.3C for 10 s, followed by a 10-minute rest, discharging was performed at 0.3C for 10 s, and then a 10-minute rest, (iii) charging was performed at 0.5C for 10 s, followed by a 10-minute rest, discharging was performed at 0.5C for 10 s, and then a 10-minute rest were carried out, and the voltage after 10 s of each charge and discharge was measured. Each current value was taken on the horizontal axis, the voltage after 10 s of each was plotted on the vertical axis, and the input / output characteristics (Ω) during charge and discharge were evaluated from the slope. The evaluation criteria were as follows. ◎: Less than 52 Ω ○: 52 Ω or more and less than 58 Ω △: 58 Ω or more and less than 64 Ω ×: 64 Ω or more

[0070] (Springback) The thickness of the secondary battery negative electrode immediately after being obtained by the method described in the section (Fabrication of secondary battery negative electrode) (negative electrode active material bulk density 1.35 g / cm 3 ) and the thickness after standing for 1 day were measured, and the difference was taken as the springback and evaluated based on the following criteria. ◎: Less than 5 μm 〇: 5 μm or more and less than 10 μm △: 10 μm or more and less than 15 μm ×: 15 μm or more

[0071] (Rebound property) From the thickness of the obtained secondary battery negative electrode after pressing and leaving it standing for one day, the thickness of the electrode layer after injecting the electrolyte described below and repeating charge and discharge 100 cycles was measured. Rebound property = (thickness of the electrode layer after 100 charge and discharge cycles) - (thickness after pressing and leaving it standing for one day) Evaluation was carried out based on the following criteria. ◎: Less than 10 μm 〇: 10 μm or more and less than 15 μm △: 15 μm or more and less than 20 μm ×: 20 μm or more

[0072] (Capacity retention rate) Regarding the secondary battery manufactured by the following method using the secondary battery negative electrode, a charge and discharge cycle of charging at a constant current until it reaches 4.2 V by the constant current constant voltage charging method at 60 °C at 2C, then charging at a constant voltage, and then discharging at a constant current of 2C until 3.0 V was performed. The cycle test was carried out up to 100 cycles, and the ratio of the discharge capacity at the 100th cycle to the initial discharge capacity was defined as the capacity retention rate and judged according to the following criteria. The larger this value is, the less the capacity reduction due to repeated charge and discharge is indicated. ◎: Capacity retention rate is 90% or more 〇: Capacity retention rate is 80% or more and less than 90% △: Capacity retention rate is 70% or more and less than 80% ×: Capacity retention rate is less than 70%

[0073] (Peel strength) A test piece with a width of 2 cm and a length of 12 cm was cut out from the obtained secondary battery negative electrode, and the surface on the current collector side of this test piece was attached to an aluminum plate with double-sided tape. In accordance with JIS Z 1522, a tape with a width of 18 mm (product name "Cellotape (registered trademark)" (manufactured by Nichiban Co., Ltd.)) was attached to the electrode layer side of the test piece, and the strength when the tape was peeled off at a speed of 100 mm / min in the 180° direction was measured 6 times, and the average value (N / 18 mm) was calculated as the peel strength (before immersion in the electrolyte). The larger these values are, the higher the adhesion strength between the current collector and the electrode layer, and it can be evaluated that it is difficult for the electrode layer to peel off from the current collector. Specifically, the peel strength was evaluated based on the following criteria. ◎: 30 N / m or more 〇: Above 20 N / m and less than 30 N / m △: Above 10 N / m and less than 20 N / m ×: Less than 10 N / m

[0074]

Table 1

Claims

1. A non-aqueous secondary battery polymer composition comprising a polymer having a unit U1 derived from a conjugated diene monomer M1, optionally, the polymer further having a unit U2 derived from an ethylenically unsaturated carboxylic acid monomer M2, the polymer further having a unit U3 derived from a monomer M3 copolymerizable with the monomer M1 and the monomer M2, the monomer M3 including an aromatic vinyl compound, a (meth)acrylate compound, and a vinyl cyanide compound, with respect to 100% by mass of all the constitutional units of the polymer, the content of the unit U1 is 0.1% by mass or more and less than 20% by mass, with respect to 100% by mass of all the constitutional units of the polymer, the content of the unit derived from the aromatic vinyl compound is 1% by mass or more and less than 60% by mass, with respect to 100% by mass of all the constitutional units of the polymer, the content of the unit derived from the (meth)acrylate compound is 15% by mass or more and less than 75% by mass, with respect to 100% by mass of all the constitutional units of the polymer, the content of the unit derived from the vinyl cyanide compound is 0.1% by mass or more and 5% by mass or less, the Young's modulus of the non-aqueous secondary battery polymer composition is less than 1.3 GPa, A non-aqueous secondary battery polymer composition in which the insoluble content of the polymer in a mixed solvent having a mass ratio of ethylene carbonate to diethyl carbonate of 1:1 is 90% or more.

2. the polymer further containing the unit U2, with respect to 100% by mass of all the constitutional units of the polymer, the content of the unit U2 is 0.1% by mass or more and 30% by mass or less, the non-aqueous secondary battery polymer composition according to Claim 1.

3. The swelling degree of the non-aqueous secondary battery polymer composition with respect to the mixed solvent is 50% or more and 200% or less, the non-aqueous secondary battery polymer composition according to Claim 1 or 2.

4. The monomer M2 includes an ethylenically unsaturated monocarboxylic acid and an ethylenically unsaturated dicarboxylic acid, The polymer composition for a non-aqueous secondary battery according to any one of claims 1 to 3, wherein the ratio of the ethylenically unsaturated monocarboxylic acid to the ethylenically unsaturated dicarboxylic acid is 1:99 to 99:

1.

5. Further including an isothiazoline-based compound The polymer composition for a non-aqueous secondary battery according to any one of claims 1 to 4, wherein the content of the isothiazoline-based compound is 0.0001% by mass or more and 1.0% by mass or less based on 100% by mass of the polymer composition for the non-secondary battery.

6. The polymer composition for a non-aqueous secondary battery according to any one of claims 1 to 5, further including an active material.

7. A negative electrode for a non-aqueous secondary battery, including the polymer composition for a non-aqueous secondary battery according to claim 6.

8. A non-aqueous secondary battery, including the negative electrode for a non-aqueous secondary battery according to claim 7.

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