Composition for adhesive layer of non-aqueous secondary battery, adhesive layer for non-aqueous secondary battery and method for manufacturing same, laminate for non-aqueous secondary battery and method for manufacturing same, and non-aqueous secondary battery

Abstract

The purpose of the present invention is to provide a composition that is for a nonaqueous secondary battery adhesive layer, that enables provision of a nonaqueous secondary battery adhesive layer capable of firmly bonding battery members to each other through pressurization at room temperature, while ensuring inkjet ejection characteristics, and that enables a nonaqueous secondary battery to exhibit excellent battery characteristics. The composition for a nonaqueous secondary battery adhesive layer according to the present invention includes a particulate polymer, and is characterized in that: the particulate polymer has a core shell structure comprising a core part and a shell part that covers a portion of the outer surface of the core part; and the shell part is composed of a polymer including an alkylene oxide group-containing monomer unit.

Description

[Technical Field]

[0001] The present invention relates to a composition for a non-aqueous secondary battery adhesive layer, an adhesive layer for a non-aqueous secondary battery and a method for producing the same, a laminate for a non-aqueous secondary battery and a method for producing the same, and a non-aqueous secondary battery. [Background technology]

[0002] Non-aqueous secondary batteries (hereinafter also referred to as "secondary batteries") such as lithium ion secondary batteries are small, lightweight, have high energy density, and can be repeatedly charged and discharged, and are therefore used in a wide range of applications. Secondary batteries generally include battery components such as a positive electrode, a negative electrode, and a separator that separates the positive electrode from the negative electrode to prevent short-circuiting between the positive electrode and the negative electrode.

[0003] In secondary batteries, battery components provided with an adhesive layer to improve adhesion between battery components are used. Specifically, battery components include an electrode formed by forming an adhesive layer on an electrode substrate, which is formed by providing an electrode mixture layer on a current collector, and a separator formed by forming an adhesive layer on a separator substrate. This adhesive layer is usually formed by supplying a slurry-like non-aqueous secondary battery adhesive layer composition (hereinafter also referred to as "adhesive layer composition") containing a binder component and a solvent such as water onto a substrate such as an electrode substrate or separator substrate, and drying it.

[0004] In recent years, in order to firmly bond battery components together while allowing the secondary battery to exhibit excellent battery characteristics and further increase the manufacturing efficiency of secondary batteries, it has been considered to form an adhesive layer (adhesive material) by ejecting an adhesive layer composition from a nozzle as fine droplets using an inkjet method. For example, Patent Document 1 describes applying a non-aqueous secondary battery slurry containing a particulate polymer having a core-shell structure, a predetermined amount of a polyhydric alcohol compound, and water by an inkjet method. Patent Document 1 also reports that by using this non-aqueous secondary battery slurry, even when the inkjet method is employed, it is possible to efficiently apply an adhesive material to the surface of a battery component while ensuring strong adhesion between battery components and excellent low-temperature output characteristics of the secondary battery. Patent Document 2 also describes applying an adhesive layer composition containing organic particles having a core-shell structure, a thixotropic agent, and water and satisfying predetermined properties by an inkjet method. Patent Document 2 also reports that by using the adhesive layer composition, an adhesive layer can be formed well even when the inkjet method is used, and that the substrate and the adherend can be firmly bonded via the adhesive layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 221056 [Patent Document 2] International Publication No. 2020 / 045246 Summary of the Invention [Problem to be solved by the invention]

[0006] However, according to the investigations of the present inventors, although the non-aqueous secondary battery slurry and adhesive layer composition of the above-mentioned conventional art can be well coated onto battery components by the inkjet method, it has become clear that when battery components are bonded together at room temperature under pressure via an adhesive layer (adhesive material) formed by drying the coated adhesive layer composition in the secondary battery manufacturing process, the adhesive strength between the battery components is insufficient, which impairs the productivity of the secondary battery and further deteriorates the battery characteristics.

[0007] That is, the above-mentioned conventional techniques still have room for improvement in terms of firmly bonding battery components together under pressure at room temperature while ensuring inkjet ejection characteristics and imparting excellent battery characteristics to the secondary battery.

[0008] Therefore, an object of the present invention is to provide a non-aqueous secondary battery adhesive layer composition that can provide a non-aqueous secondary battery adhesive layer that can firmly bond battery components together under pressure at room temperature while ensuring inkjet ejection characteristics, and that can enable the non-aqueous secondary battery to exhibit excellent battery characteristics. Another object of the present invention is to provide an adhesive layer for a non-aqueous secondary battery that can firmly bond battery components together under pressure at room temperature and that can enable the non-aqueous secondary battery to exhibit excellent electrical properties. Another object of the present invention is to provide a laminate for a non-aqueous secondary battery that can enable the non-aqueous secondary battery to exhibit excellent electrical properties. Another object of the present invention is to provide a non-aqueous secondary battery having excellent electrical characteristics. Another object of the present invention is to provide a method for producing an adhesive layer for a non-aqueous secondary battery that can firmly bond battery components together under pressure at room temperature and enable the non-aqueous secondary battery to exhibit excellent electrical properties. Another object of the present invention is to provide a method for producing a laminate for a non-aqueous secondary battery that can provide excellent electrical properties to the non-aqueous secondary battery. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems, and have found that in a composition for a non-aqueous secondary battery adhesive layer containing a particulate polymer having a core-shell structure, if an alkylene oxide group-containing monomer unit is contained in the polymer constituting the shell portion of the core-shell structure, it is possible to firmly bond battery components together under pressure at room temperature while maintaining inkjet ejection characteristics, and to enable a non-aqueous secondary battery to exhibit excellent battery characteristics, thereby completing the present invention.

[0010] That is, the present invention aims to advantageously solve the above-mentioned problems, and provides the following (1) to (7) adhesive compositions for non-aqueous secondary batteries, (8) adhesive layers for non-aqueous secondary batteries, (9) methods for producing adhesive layers for non-aqueous secondary batteries, (10) laminates for non-aqueous secondary batteries, (11) methods for producing laminates for non-aqueous secondary batteries, and (12) non-aqueous secondary batteries. (1) A non-aqueous secondary battery adhesive layer composition containing a particulate polymer, wherein the particulate polymer has a core-shell structure having a core portion and a shell portion partially covering the outer surface of the core portion, and the shell portion is made of a polymer containing an alkylene oxide group-containing monomer unit. In this way, by using a composition for a non-aqueous secondary battery adhesive layer in which the polymer constituting the shell portion of the particulate polymer having a core-shell structure contains an alkylene oxide group-containing monomer unit, it is possible to firmly bond battery components together under pressure at room temperature while ensuring inkjet ejection characteristics, and it is possible to enable the non-aqueous secondary battery to exhibit excellent battery characteristics.

[0011] (2) The composition for a non-aqueous secondary battery adhesive layer according to (1) above, wherein the polymer constituting the shell portion contains 3% by mass or more and 60% by mass or less of the alkylene oxide group-containing monomer unit. In this way, if the polymer constituting the shell portion contains alkylene oxide group-containing monomer units at a predetermined content ratio, the battery components can be more firmly bonded together under pressure at room temperature, and the affinity of the polymer constituting the shell portion to the electrolyte solution can be increased, thereby improving the battery characteristics.

[0012] (3) The composition for a non-aqueous secondary battery adhesive layer according to (1) or (2) above, wherein the polymer constituting the shell portion contains 35% by mass or more and 96% by mass or less of aromatic vinyl monomer units. In this way, if the polymer constituting the shell contains aromatic vinyl monomer units at a predetermined content ratio, the battery components can be bonded together more firmly by applying pressure at room temperature.

[0013] (4) The composition for a non-aqueous secondary battery adhesive layer according to any one of (1) to (3) above, wherein the core portion is made of a polymer containing 50% by mass or more and 98% by mass or less of (meth)acrylic acid ester monomer units. In this way, if the core portion is made of a polymer containing 50% by mass or more and 98% by mass or less of (meth)acrylic acid ester monomer units, the battery components can be bonded together more firmly under pressure at room temperature.

[0014] (5) The nonaqueous secondary battery adhesive layer composition according to any one of (1) to (4), wherein the polymer constituting the core portion has a glass transition temperature of −50° C. or higher and 25° C. or lower, and the polymer constituting the shell portion has a glass transition temperature of 50° C. or higher and 200° C. or lower. In this way, if the glass transition temperatures of the polymers constituting the core portion and the polymers constituting the shell portion are each within a predetermined range, nozzle clogging can be further suppressed when an inkjet method is employed, thereby further improving the inkjet ejection characteristics, and the battery components can be more firmly bonded together under pressure at room temperature, allowing the nonaqueous secondary battery to exhibit even better battery characteristics. In the present invention, the "glass transition temperature" can be measured using the measurement method described in the Examples of this specification.

[0015] (6) The non-aqueous secondary battery adhesive layer composition according to (5) above, wherein the polymer constituting the core portion has a glass transition temperature of −40° C. or higher and 25° C. or lower. In this way, if the glass transition temperature of the polymer constituting the core portion is within the above-mentioned predetermined range, the battery components can be bonded together more firmly by applying pressure at room temperature.

[0016] (7) The composition for a non-aqueous secondary battery adhesive layer according to any one of (1) to (6) above, wherein the particulate polymer has a volume average particle size of 100 nm or more and 1500 nm or less. Thus, when the volume average particle diameter of the particulate polymer is 100 nm or more, deterioration of battery characteristics due to an increase in the resistance of the secondary battery caused by blocking the lithium ion pathway in the substrate (electrode or separator) can be suppressed. Also, when the volume average particle diameter is 1500 nm or less, nozzle clogging can be further suppressed when the nonaqueous secondary battery adhesive layer composition is applied by an inkjet method, thereby improving inkjet ejection characteristics. In the present invention, the "volume average particle size" refers to the particle size at which the cumulative volume calculated from the smallest diameter side becomes 50% in the volume-based particle size distribution measured by a laser diffraction method, and can be measured using the measurement method described in the examples of this specification.

[0017] (8) An adhesive layer for a non-aqueous secondary battery, which is formed using the composition for a non-aqueous secondary battery adhesive layer according to any one of (1) to (7) above. In this way, the adhesive layer for a non-aqueous secondary battery formed using the composition for a non-aqueous secondary battery adhesive layer described in any one of (1) to (7) above can firmly bond battery components such as separators and electrodes together by applying pressure at room temperature, and can also enable the non-aqueous secondary battery to exhibit excellent battery characteristics.

[0018] (9) A step of applying the non-aqueous secondary battery adhesive layer composition according to any one of (1) to (7) above onto a substrate by an inkjet method; and drying the composition for a non-aqueous secondary battery adhesive layer applied to the substrate. In this way, by using the composition for a nonaqueous secondary battery adhesive layer described in any one of (1) to (7) above, even when an inkjet method is employed, nozzle clogging can be suppressed and inkjet ejection characteristics can be ensured, so that a nonaqueous secondary battery adhesive layer can be satisfactorily formed on a substrate.

[0019] (10) A laminate for a non-aqueous secondary battery comprising an electrode and a separator, A laminate for a non-aqueous secondary battery, wherein the electrode and the separator are bonded via the adhesive layer for a non-aqueous secondary battery according to (8) above. In this way, in a laminate for a non-aqueous secondary battery including battery components bonded using the adhesive layer for a non-aqueous secondary battery described in (8) above, the battery components are firmly bonded to each other, and a non-aqueous secondary battery including the laminate for a non-aqueous secondary battery can exhibit excellent battery characteristics.

[0020] (11) applying an adhesive material to at least one of the bonding surfaces of the electrode and the separator; and a step of applying pressure to the electrode and the separator at room temperature via the bonding surfaces to which the adhesive material has been applied, A method for producing a laminate for a non-aqueous secondary battery, wherein the adhesive material is a composition for a non-aqueous secondary battery adhesive layer according to any one of (1) to (7) above. In this way, by using an adhesive material obtained from the non-aqueous secondary battery adhesive layer composition according to any one of (1) to (7) above, electrodes can be firmly bonded together at room temperature. In the present invention, "room temperature" refers to a temperature in the range of 25°C ± 5°C.

[0021] (12) A non-aqueous secondary battery comprising the laminate for a non-aqueous secondary battery according to (10) above. In this way, a non-aqueous secondary battery including the laminate for a non-aqueous secondary battery described in (10) above can exhibit excellent battery characteristics. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a non-aqueous secondary battery adhesive layer that can firmly bond battery components together under pressure at room temperature while ensuring inkjet ejection characteristics, and it is also possible to provide a non-aqueous secondary battery adhesive layer composition that can enable a non-aqueous secondary battery to exhibit excellent battery characteristics. Furthermore, the present invention can provide an adhesive layer for a non-aqueous secondary battery that can firmly bond battery components together under pressure at room temperature and enable the non-aqueous secondary battery to exhibit excellent electrical properties. Furthermore, according to the present invention, it is possible to provide a laminate for a non-aqueous secondary battery that can enable the non-aqueous secondary battery to exhibit excellent electrical properties. Furthermore, the present invention can provide a non-aqueous secondary battery with excellent electrical characteristics. Furthermore, the present invention can provide a method for producing an adhesive layer for a non-aqueous secondary battery that can firmly bond battery components together under pressure at room temperature and enable the non-aqueous secondary battery to exhibit excellent electrical properties. Furthermore, the present invention can provide a method for producing a laminate for a non-aqueous secondary battery that can provide excellent electrical properties to the non-aqueous secondary battery. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating the structure of an example of a particulate polymer. [Figure 2] 1A to 1C are diagrams illustrating an example of a process for producing a laminate for a non-aqueous secondary battery according to the present invention. [Figure 3] 1A to 1C are diagrams illustrating the manufacturing process of a laminate for a non-aqueous secondary battery in Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described in detail. Here, the non-aqueous secondary battery adhesive layer composition of the present invention can be used when forming the non-aqueous secondary battery adhesive layer of the present invention. The non-aqueous secondary battery adhesive layer of the present invention can be produced, for example, by the non-aqueous secondary battery adhesive layer production method of the present invention. The non-aqueous secondary battery adhesive layer of the present invention can be used when producing the non-aqueous secondary battery laminate of the present invention and the non-aqueous secondary battery of the present invention. The non-aqueous secondary battery laminate of the present invention can be used when producing the non-aqueous secondary battery of the present invention, and can be produced, for example, by the non-aqueous secondary battery laminate production method of the present invention. And the non-aqueous secondary battery of the present invention includes the non-aqueous secondary battery laminate of the present invention.

[0025] (Non-aqueous secondary battery adhesive layer composition) The non-aqueous secondary battery adhesive layer composition of the present invention contains a particulate polymer having a core-shell structure, and optionally further contains a particulate polymer not having a core-shell structure and other components. The non-aqueous secondary battery adhesive layer composition of the present invention is usually a slurry composition containing water or the like as a solvent (dispersion medium). Here, the particulate polymer having a core-shell structure contained in the non-aqueous secondary battery adhesive layer composition of the present invention is characterized in that the shell portion is made of a polymer containing an alkylene oxide group-containing monomer unit. Furthermore, the composition for a non-aqueous secondary battery adhesive layer of the present invention contains a particulate polymer having a core-shell structure with the above-mentioned specified shell portion, and therefore can firmly bond battery components together under pressure at room temperature while ensuring inkjet ejection characteristics, and can enable a non-aqueous secondary battery to exhibit excellent battery characteristics.

[0026] <Particulate polymer with core-shell structure> The particulate polymer having a core-shell structure contained in the nonaqueous secondary battery adhesive layer composition of the present invention is a component that functions as a binder in the adhesive layer (adhesive material) that bonds battery components such as separators and electrodes together.

[0027] <<Structure of particulate polymers with core-shell structure>> The particulate polymer contained in the non-aqueous secondary battery adhesive layer composition of the present invention has a core-shell structure comprising a core portion and a shell portion covering the outer surface of the core portion.

[0028] Here, the shell portion may cover the entire outer surface of the core portion or may cover only a portion of the outer surface of the core portion. Even if the outer surface of the core portion appears to be completely covered by the shell portion, the shell portion partially covers the outer surface of the core portion as long as it has holes that communicate between the inside and outside of the shell portion.

[0029] The cross-sectional structure of an example of a particulate polymer is shown in FIG. 1. In FIG. 1, a particulate polymer 300 has a core-shell structure including a core portion 310 and a shell portion 320. Here, the core portion 310 is a portion of the particulate polymer 300 that is located more inward than the shell portion 320. The shell portion 320 is a portion that covers an outer surface 310S of the core portion 310, and is usually the outermost portion of the particulate polymer 300. In the example of FIG. 1, the shell portion 320 does not cover the entire outer surface 310S of the core portion 310, but only partially covers the outer surface 310S of the core portion 310.

[0030] The particulate polymer may have any constituent element other than the core and shell as described above, as long as the intended effect is not significantly impaired. Specifically, for example, the particulate polymer may have a portion formed of a polymer different from the core inside the core. As a specific example, seed particles used when producing the particulate polymer by seed polymerization may remain inside the core. However, from the viewpoint of significantly exhibiting the intended effect, it is preferable that the particulate polymer has only the core and shell.

[0031] [Core] -composition- Examples of monomers used to prepare the core polymer include vinyl chloride monomers such as vinyl chloride and vinylidene chloride; vinyl acetate monomers such as vinyl acetate; aromatic vinyl monomers such as styrene, α-methylstyrene, styrene sulfonic acid, butoxystyrene, and vinylnaphthalene; vinylamine monomers such as vinylamine; vinylamide monomers such as N-vinylformamide and N-vinylacetamide; methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate. Examples of the monomers include fluorine-free (meth)acrylic acid ester monomers such as ethyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate; (meth)acrylamide monomers such as acrylamide and methacrylamide; (meth)acrylonitrile monomers such as acrylonitrile and methacrylonitrile; fluorine-containing (meth)acrylic acid ester monomers such as 2-(perfluorohexyl)ethyl methacrylate and 2-(perfluorobutyl)ethyl acrylate; maleimide; and maleimide derivatives such as phenylmaleimide. These monomers may be used alone or in combination of two or more at any ratio. In the present invention, (meth)acrylic means acrylic and / or methacrylic, and (meth)acrylonitrile means acrylonitrile and / or methacrylonitrile.

[0032] Among these monomers, from the viewpoint of further firmly bonding battery components together via the adhesive layer, it is preferable to use at least a (meth)acrylic acid ester monomer as the monomer used to prepare the core polymer, and a combination of a (meth)acrylic acid ester monomer and an aromatic vinyl monomer, or a combination of a (meth)acrylic acid ester monomer and a (meth)acrylonitrile monomer is more preferable, and a combination of a (meth)acrylic acid ester monomer and an aromatic vinyl monomer is particularly preferable. That is, the core polymer preferably contains at least a (meth)acrylic acid ester monomer unit, more preferably a (meth)acrylic acid ester monomer unit and an aromatic vinyl monomer unit or a (meth)acrylonitrile monomer unit, and even more preferably a (meth)acrylic acid ester monomer unit and an aromatic vinyl monomer unit. In the present invention, "containing a monomer unit" means that "a polymer obtained using the monomer contains a repeating unit derived from the monomer." In the present invention, the term "(meth)acrylic acid ester monomer" refers to a monofunctional (meth)acrylic acid ester monomer having only one polymerization reactive group.

[0033] From the viewpoint of further firmly bonding battery components together via the adhesive material, the proportion of (meth)acrylic acid ester monomer units in the core polymer is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 65% ​​by mass or more, and is preferably 98% by mass or less, more preferably 96% by mass or less, even more preferably 85% by mass or less, and particularly preferably 80% by mass or less, where all repeating units (all monomer units) contained in the core polymer are taken as 100% by mass. Furthermore, when the core polymer contains (meth)acrylic acid ester monomer units and aromatic vinyl monomer units, the proportion of the aromatic vinyl monomer units in the core polymer is preferably 15% by mass or more, more preferably 20% by mass or more, and particularly preferably 25% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the core polymer, from the viewpoint of further firmly bonding battery components together via the adhesive material. Furthermore, when the core polymer contains (meth)acrylic acid ester monomer units and (meth)acrylonitrile monomer units, the proportion of the (meth)acrylonitrile monomer units in the core polymer is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 30% by mass or less, and more preferably 25% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the core polymer, from the viewpoint of further firmly bonding the battery components together via the adhesive material.

[0034] The core polymer may also contain an acid group-containing monomer unit. Examples of the acid group-containing monomer include a monomer having an acid group, such as a monomer having a carboxylic acid group, a monomer having a sulfonic acid group, or a monomer having a phosphoric acid group.

[0035] Examples of the monomer having a carboxylic acid group include monocarboxylic acids and dicarboxylic acids. Examples of the monocarboxylic acids include acrylic acid, methacrylic acid, and crotonic acid. Examples of the dicarboxylic acids include maleic acid, fumaric acid, and itaconic acid. Examples of the monomer having a sulfonic acid group include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth)allyl sulfonic acid, (meth)acrylic acid-2-ethyl sulfonate, 2-acrylamido-2-methylpropanesulfonic acid, and 3-allyloxy-2-hydroxypropanesulfonic acid. Furthermore, examples of the monomer having a phosphate group include 2-(meth)acryloyloxyethyl phosphate, methyl-2-(meth)acryloyloxyethyl phosphate, and ethyl-(meth)acryloyloxyethyl phosphate. In the present invention, (meth)allyl means allyl and / or methallyl, and (meth)acryloyl means acryloyl and / or methacryloyl. Among these, as the acid group-containing monomer, a monomer having a carboxylic acid group is preferred, and among these, a monocarboxylic acid is preferred, and (meth)acrylic acid is more preferred. The acid group-containing monomer may be used alone or in combination of two or more kinds in any ratio.

[0036] The proportion of the acid group-containing units in the core polymer is preferably 0.1% by mass or more, more preferably 1% by mass or more, and preferably 15% by mass or less, more preferably 10% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the core polymer. By keeping the proportion of the acid group-containing units within the above range, the dispersibility of the core polymer can be improved during preparation of the particulate polymer, and it can be made easier to form a shell portion that partially covers the outer surface of the core polymer.

[0037] In addition to the above-mentioned monomer units, the core polymer preferably contains a crosslinkable monomer unit. The crosslinkable monomer is a monomer that can form a crosslinked structure during or after polymerization by heating or irradiation with energy rays.

[0038] Examples of crosslinkable monomers include polyfunctional monomers having two or more polymerization reactive groups. Examples of such polyfunctional monomers include divinyl monomers such as divinylbenzene, 1,3-butadiene, isoprene, and allyl methacrylate; di(meth)acrylic acid ester monomers such as ethylene dimethacrylate, diethylene glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, and 1,3-butylene glycol diacrylate; tri(meth)acrylic acid ester monomers such as trimethylolpropane trimethacrylate and trimethylolpropane triacrylate; ethylenically unsaturated monomers containing epoxy groups such as allyl glycidyl ether and glycidyl methacrylate; and γ-methacryloxypropyltrimethoxysilane. Among these, di(meth)acrylic acid ester monomers are more preferred. These may be used alone or in combination of two or more in any ratio.

[0039] Furthermore, the proportion of crosslinkable monomer units in the core polymer is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and particularly preferably 0.4% by mass or more, and is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less, where the total repeating units (total monomer units) contained in the core polymer is 100% by mass. By keeping the proportion of crosslinkable monomer units within the above range, the battery components can be more firmly bonded together via the adhesive layer.

[0040] - Glass transition temperature - The glass transition temperature of the polymer in the core portion of the particulate polymer is preferably -50°C or higher, more preferably -45°C or higher, even more preferably -40°C or higher, and preferably 25°C or lower, more preferably 10°C or lower, and even more preferably 0°C or lower. If the glass transition temperature of the polymer in the core portion is equal to or higher than the lower limit, inkjet ejection characteristics can be improved. On the other hand, if the glass transition temperature of the polymer in the core portion is equal to or lower than the upper limit, the polymer in the core portion can exhibit good adhesive properties, and battery components can be more firmly bonded together via the adhesive layer even when pressurized at room temperature. The glass transition temperature of the core polymer can be adjusted, for example, by changing the type and ratio of the monomers used in preparing the core polymer.

[0041] [Shell part] -composition- The polymer constituting the shell portion contains alkylene oxide group-containing monomer units, and may optionally further contain other monomer units. The polymer used for the shell portion of the particulate polymer having a core-shell structure contained in the nonaqueous secondary battery adhesive layer composition of the present invention will be described in detail below.

[0042] --Alkylene oxide group-containing monomer unit-- The alkylene oxide group-containing monomer capable of forming the alkylene oxide group-containing monomer unit contained in the polymer used for the shell portion is not particularly limited as long as it has an alkylene oxide group. The alkylene oxide group-containing monomer preferably has one polymerizable unsaturated bond, preferably has a chain alkylene oxide group, and more preferably has one polymerizable unsaturated bond and a chain alkylene oxide group. When A represents an alkylene group, each alkylene oxide group constituting the alkylene oxide chain in the alkylene oxide group-containing monomer unit may be represented by either ?AO? or ?OA?. The number of alkylene oxide groups is not particularly limited, but is preferably 2 or more, more preferably 5 or more, and even more preferably 9 or more, and is preferably 30 or less, and more preferably 25 or less. When the number of alkylene oxide groups is within the above range, the mechanical stability of the particulate polymer can be improved. The alkylene oxide chain may contain a mixture of alkylene oxide groups with different carbon numbers, for example, alkylene oxide groups with different carbon numbers, such as ethylene oxide groups, propylene oxide groups, and butylene oxide groups, may be bonded randomly or in blocks to the alkylene oxide chain.

[0043] Here, examples of alkylene oxide group-containing monomers that can form alkylene oxide group-containing monomer units include (poly)oxyalkylene alkenyl ethers and (poly)oxyalkylene (meth)acrylic acid esters having (meth)acryloyl groups at their terminals.

[0044] The alkenyl group in the (poly)oxyalkylene alkenyl ether is not particularly limited, and examples thereof include alkenyl groups having 2 to 10 carbon atoms. Specific examples of the alkenyl group include a vinyl group (ethenyl group, -CH=CH2), an allyl group (2-propenyl group, -CH2-CH=CH2), a 1-propenyl group (-CH=CH-CH3), an isopropenyl group (-C(CH3)=CH2), a 1-butenyl group (-CH=CH-CH2-CH3), a 2-butenyl group (-CH2-CH=CH-CH3), and a 3-butenyl group (-CH2-CH2-CH=CH2). The alkylene group in the (poly)oxyalkylene alkenyl ether is not particularly limited, but examples thereof include linear or branched alkylene groups such as methylene, ethylene, propylene, and butylene. The number of alkylene oxide groups (oxyalkylene groups) in the (poly)oxyalkylene alkenyl ether is not particularly limited, but is preferably 2 or more, more preferably 5 or more, and even more preferably 9 or more, and is preferably 30 or less, and more preferably 25 or less. When the number of alkylene oxide groups is within the above range, the mechanical stability of the particulate polymer can be improved. Specific examples of the (poly)oxyalkylene alkenyl ether include (poly)oxyethylene vinyl ether, (poly)oxypropylene vinyl ether, (poly)oxyethylene allyl ether, (poly)oxypropylene allyl ether, (poly)oxyethylene butenyl ether, (poly)oxypropylene butenyl ether, (poly)oxyethylene pentenyl ether, and (poly)oxypropylene pentenyl ether.

[0045] The (poly)oxyalkylene (meth)acrylic acid ester having a (meth)acryloyl group at its terminal is not particularly limited, but from the viewpoint of copolymerizability, a (poly)oxyalkylene (meth)acrylic acid ester represented by the following formula (I) is preferred. [ka] (In formula (I), A represents an alkylene group which may have a substituent, R represents a hydrogen atom or a methyl group, R' represents a hydrogen atom, an alkyl group which may have a substituent, or a phenyl group, n is a positive integer, and the number of carbon atoms in A may differ for each repeating unit of the alkylene oxide group (-AO-).)

[0046] In the above formula (I), the alkylene group of A is not particularly limited and examples thereof include linear or branched alkylene groups such as an ethylene group, a propylene group, a butylene group, etc. Among these, the alkylene group of A is preferably an ethylene group or a propylene group, and particularly preferably an ethylene group. Furthermore, the substituent that the alkylene group of A may have is not particularly limited, and examples thereof include substituents other than alkyl groups, specifically, hydroxyl groups; cyano groups; amino groups; substituted amino groups such as dimethylamino groups; alkoxy groups having 1 to 10 carbon atoms such as methoxy groups, ethoxy groups, and propoxy groups; nitro groups; cycloalkyl groups having 3 to 10 carbon atoms such as cyclopropyl groups and cyclohexyl groups; and aryl groups such as phenyl groups and naphthyl groups.

[0047] In the above formula (I), A is not particularly limited and examples thereof include linear or branched alkylene groups such as an ethylene group, a propylene group, and a butylene group, which may have the above-mentioned substituents. A in the above formula (I) is preferably an ethylene group, a propylene group, or a butylene group, more preferably an ethylene group or a propylene group, and particularly preferably an ethylene group.

[0048] In the above formula (I), the alkyl group for R' is not particularly limited and examples thereof include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 1-methylpentyl, 1-ethylpentyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 2-ethylhexyl, isohexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl. Among these, methyl, ethyl, n-propyl, and isopropyl groups are preferred, with methyl and n-propyl groups being more preferred, and methyl being particularly preferred. The substituent that the alkyl group of R′ may have is not particularly limited, and examples thereof include the same substituents that the alkylene group of A may have. R' in the above formula (I) is not particularly limited, and examples thereof include a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have the above-mentioned substituent, a phenyl group, etc. R' in the above formula (I) is preferably a hydrogen atom, a methyl group, or an ethyl group, more preferably a hydrogen atom or a methyl group, and particularly preferably a methyl group.

[0049] In the above formula (I), n is not particularly limited, but is preferably 2 or more, more preferably 5 or more, and even more preferably 9 or more, and is preferably 30 or less, and more preferably 25 or less. When n is within the above range, the mechanical stability of the particulate polymer can be improved.

[0050] Furthermore, the (poly)oxyalkylene (meth)acrylic acid ester represented by the above formula (I) may have an alkylene oxide chain in which alkylene oxide groups such as ethylene oxide groups, propylene oxide groups, and butylene oxide groups are bonded randomly or in blocks.

[0051] Specific examples of the (poly)oxyalkylene (meth)acrylic acid ester represented by the above formula (I) include polyalkylene glycol (meth)acrylates having a polyethylene oxide chain, polyalkylene glycol (meth)acrylates having a polypropylene oxide chain, polyalkylene glycol (meth)acrylates having a polybutylene oxide chain, and polyalkylene glycol (meth)acrylates having both a polyethylene oxide chain and a polypropylene oxide chain.

[0052] Examples of polyalkylene glycol (meth)acrylates having a polyethylene oxide chain include methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, and polyethylene glycol (meth)acrylate. Examples of polyalkylene glycol (meth)acrylates having a polypropylene oxide chain include methoxypolypropylene glycol (meth)acrylate, ethoxypolypropylene glycol (meth)acrylate, and polypropylene glycol (meth)acrylate. Examples of polyalkylene glycol (meth)acrylates having a polybutylene oxide chain include methoxypolybutylene glycol (meth)acrylate, ethoxypolybutylene glycol (meth)acrylate, and polybutylene glycol (meth)acrylate. Examples of polyalkylene glycol (meth)acrylates having both polyethylene oxide and polypropylene oxide chains include polyethylene glycol-polypropylene glycol (meth)acrylate. The above compound is an ester compound of (meth)acrylic acid and polyoxyalkylene ether and can be synthesized by various known methods, but from the viewpoint of availability, it is preferable to use commercially available products.

[0053] Here, examples of commercially available (poly)oxyalkylene (meth)acrylic acid esters include, but are not limited to, NK Ester AM30G (methoxypolyethylene glycol acrylate, number of repeating alkylene oxide groups: n≈3), NK Ester M40G (methoxypolyethylene glycol methacrylate, n≈4), NK Ester AM90G (methoxypolyethylene glycol acrylate, n≈9), NK Ester M90G (methoxypolyethylene glycol methacrylate, n≈9), NK Ester AM130G (methoxypolyethylene glycol acrylate, n≈13), and NK Ester AM230G (methoxypolyethylene glycol acrylate, n≈23) (all manufactured by Shin-Nakamura Chemical Co., Ltd.); Blenmer E (hydroxyethyl methacrylate, n = 1), Blenmer PE-90 (polyethylene glycol monomethacrylate, n ≒ 2), Blenmer PE-200 (polyethylene glycol monomethacrylate, n ≒ 4.5), Blenmer PE-350 (polyethylene glycol monomethacrylate, n ≒ 8), Blenmer P (hydroxypropyl methacrylate, n = 1), Blenmer PP-1000 (polypropylene glycol monomethacrylate, n ≒ 4-6), Blenmer PP-500 (polypropylene glycol monomethacrylate, n ≒ 9), Blenmer 50PEP-300 (polyethylene glycol polypropylene glycol monomethacrylate, EO≒3.5, PO≒2.5, random), Blemmer 55PET-800 (polyethylene glycol polybutylene glycol monomethacrylate, EO≒10, BO≒5, random), Blemmer AE-200 (polyethylene glycol monoacrylate, n≒4.5), Blemmer AE-400 (polyethylene glycol monoacrylate, n≒10), Blemmer AP-400 (polypropylene glycol monomethacrylate, n≒6) (all manufactured by NOF Corporation); and Examples include Light Acrylate EC-A (ethoxy-diethylene glycol acrylate, n=2), Light Acrylate MTG-A (methoxy-triethylene glycol acrylate, n=3), Light Acrylate EHDG-AT (2-ethylhexyl-diglycol acrylate, n=2), Light Acrylate 130-A (methoxy-polyethylene glycol acrylate, n≒9), Light Acrylate P2H-A (phenoxydiethylene glycol acrylate, n=2), and Light Ester 130-MA (methoxy-polyethylene glycol methacrylate, n≒9) (all manufactured by Kyoeisha Chemical Co., Ltd.).

[0054] The alkylene oxide group-containing monomers described above can be used alone or in combination of two or more. In the present invention, the "alkylene oxide group-containing monomer" is not included in the (meth)acrylic acid ester monomer, (meth)acrylonitrile monomer, aromatic vinyl monomer, and crosslinkable monomer, which will be described later as other monomers.

[0055] The proportion of alkylene oxide group-containing monomer units in the shell polymer is preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 16% by mass or more, and preferably 60% by mass or less, and more preferably 50% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the shell polymer. When the proportion of alkylene oxide group-containing monomer units is equal to or greater than the lower limit, battery components can be more firmly bonded together under pressure at room temperature, and the affinity of the shell polymer for the electrolyte solution can be increased, improving battery performance. When the proportion of alkylene oxide group-containing monomer units is equal to or less than the upper limit, elution of the shell polymer into the electrolyte solution can be suppressed.

[0056] --Other Monomer Units-- Examples of monomers that can form other monomer units optionally contained in the polymer that constitutes the shell include the same monomers as those exemplified as monomers that can be used to produce the polymer that constitutes the core (e.g., (meth)acrylic acid ester monomer units, (meth)acrylonitrile monomers, aromatic vinyl monomers, and crosslinkable monomers). One type of such monomer may be used alone, or two or more types may be used in combination in any ratio.

[0057] Among these monomers, it is preferable to use at least one of a (meth)acrylic acid ester monomer and an aromatic vinyl monomer as the monomer used to prepare the shell polymer, from the viewpoint of more firmly bonding the battery components together via the adhesive layer. That is, the shell polymer preferably contains at least one of a (meth)acrylic acid ester monomer unit and an aromatic vinyl monomer unit, and more preferably contains an aromatic vinyl monomer unit.

[0058] From the viewpoint of bonding battery components together more firmly via the adhesive layer, the proportion of (meth)acrylic acid ester monomer units in the polymer of the shell portion is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, and is preferably 30% by mass or less, and more preferably 20% by mass or less, where all repeating units (all monomer units) contained in the polymer of the shell portion are taken as 100% by mass.

[0059] Furthermore, from the viewpoint of bonding battery components together more firmly via the adhesive layer, the proportion of aromatic vinyl monomer units in the polymer of the shell portion is preferably 35% by mass or more, more preferably 45% by mass or more, and is preferably 96% by mass or less, and more preferably 93% by mass or less, where all repeating units (all monomer units) contained in the polymer of the shell portion are taken as 100% by mass.

[0060] The shell polymer may contain, in addition to (meth)acrylic acid ester monomer units and aromatic vinyl monomer units, acid group-containing monomer units. Examples of the acid group-containing monomer include monomers having an acid group, such as monomers having a carboxylic acid group, monomers having a sulfonic acid group, and monomers having a phosphoric acid group. Specifically, the acid group-containing monomer may be the same as the acid group-containing monomer that can be used to form the core. Among these, as the acid group-containing monomer, a monomer having a carboxylic acid group is preferred, among which a monocarboxylic acid is more preferred, and (meth)acrylic acid is even more preferred. The acid group-containing monomer may be used alone or in combination of two or more kinds in any ratio. The proportion of the acid group-containing monomer units in the shell polymer is preferably 0.1% by mass or more, more preferably 0.4% by mass or more, and even more preferably 0.7% by mass or more, and is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, where the total repeating units (total monomer units) contained in the shell polymer is 100% by mass. By keeping the proportion of the acid group-containing monomer units within the above range, the dispersibility of the particulate polymer can be improved, and the battery components can be bonded together more firmly via the adhesive layer.

[0061] The polymer of the shell portion may contain a crosslinkable monomer unit. Examples of the crosslinkable monomer include the same monomers as those exemplified as the crosslinkable monomers that can be used in the polymer of the core portion. Among these, di(meth)acrylic acid ester monomers and allyl methacrylate are preferred. The crosslinkable monomer may be used alone or in combination of two or more types in any ratio.

[0062] The proportion of crosslinkable monomer units in the polymer of the shell portion is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more, and is preferably 4% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less, with all repeating units (all monomer units) contained in the polymer of the shell portion being 100% by mass.

[0063] - Glass transition temperature - The glass transition temperature of the shell polymer of the particulate polymer having a core-shell structure is preferably 50°C or higher, more preferably 55°C or higher, even more preferably 60°C or higher, even more preferably 95°C or higher, and preferably 200°C or lower, more preferably 120°C or lower. If the glass transition temperature of the shell polymer is above the lower limit, the inkjet ejection characteristics can be further improved. On the other hand, if the glass transition temperature of the shell polymer is below the upper limit, the particulate polymer becomes appropriately soft, allowing the battery components to be more firmly bonded together at room temperature via the adhesive layer. The glass transition temperature of the shell polymer can be adjusted, for example, by changing the types and proportions of the monomers used in preparing the shell polymer.

[0064] The glass transition temperature of the polymer in the shell portion is preferably at least 25°C higher, and more preferably at least 50°C higher, than the glass transition temperature of the polymer in the core portion described above, from the viewpoint of maintaining the shape of the particulate polymer after bonding the battery components together and suppressing an increase in resistance.

[0065] [Mass ratio of shell to total of core and shell] In the particulate polymer having a core-shell structure, the mass ratio of the shell portion to the total of the core portion and the shell portion is preferably 2% by mass or more, more preferably 5% by mass or more, and preferably 15% by mass or less, and more preferably 10% by mass or less. When the mass ratio of the shell portion is equal to or greater than the lower limit, inkjet ejection characteristics can be further improved. On the other hand, when the mass ratio of the shell portion is equal to or less than the upper limit, battery components can be more firmly bonded together when pressurized at room temperature, and the secondary battery can exhibit even better battery characteristics. Here, the mass proportion of the shell portion in the total of the core portion and the shell portion is determined from the ratio of the thickness of the core portion to the thickness of the shell portion, which will be described later, and the specific gravity of the particulate polymer.

[0066] [Volume average particle size of particulate polymer having core-shell structure] The volume average particle diameter of the particulate polymer having a core-shell structure is preferably 100 nm or more, more preferably 200 nm or more, and preferably 1500 nm or less, more preferably 900 nm or less, even more preferably 800 nm or less, and even more preferably 700 nm or less. When the volume average particle diameter of the particulate polymer having a core-shell structure is 100 nm or more, deterioration of battery characteristics due to an increase in secondary battery resistance caused by blocking the lithium ion pathway in the substrate (electrode or separator) can be suppressed. Furthermore, when the volume average particle diameter is 1500 nm or less, nozzle clogging can be further suppressed when the nonaqueous secondary battery adhesive layer composition is applied by an inkjet method, thereby improving inkjet ejection characteristics.

[0067] [Ratio of average shell thickness to volume average particle diameter] The ratio of the average thickness of the shell portion to the volume average particle diameter of the particulate polymer having a core-shell structure is preferably 0.1% or more, more preferably 0.5% or more, and preferably 15% or less, more preferably 10% or less. If the average thickness of the shell portion is equal to or greater than the above lower limit, the inkjet ejection characteristics can be further improved. Furthermore, if the average thickness of the shell portion is equal to or less than the above upper limit, the battery components can be more firmly bonded to each other when pressed at room temperature.

[0068] Here, the average thickness of the shell portion of a particulate polymer having a core-shell structure is determined by observing the cross-sectional structure of the particulate polymer having a core-shell structure using a transmission electron microscope (TEM). Specifically, the maximum thickness of the shell portion in the cross-sectional structure of the particulate polymer is measured using a TEM, and the average value of the maximum thicknesses of the shell portions of 20 or more arbitrarily selected particulate polymer particles is taken as the average thickness of the shell portion. However, when the shell portion is composed of polymer particles and the particles constituting the shell portion do not overlap each other in the radial direction of the particulate polymer particles, and these polymer particles form a single layer of the shell portion, the number-average particle diameter of the particles constituting the shell portion is taken as the average thickness of the shell portion.

[0069] [Method for preparing particulate polymer having core-shell structure] The particulate polymer having the core-shell structure can be prepared by, for example, using a monomer for the core polymer and a monomer for the shell polymer, polymerizing them stepwise while changing the ratio of these monomers over time. Specifically, the particulate polymer can be prepared by a continuous multi-stage emulsion polymerization method or multi-stage suspension polymerization method in which the polymer in the earlier stage is successively coated with the polymer in the later stage.

[0070] Therefore, an example of obtaining a particulate polymer having the above-mentioned core-shell structure by a multistage emulsion polymerization method will be described below.

[0071] For the polymerization, an emulsifier may be used according to a conventional method, such as an anionic surfactant such as sodium dodecylbenzenesulfonate or sodium dodecyl sulfate, a nonionic surfactant such as polyoxyethylene nonylphenyl ether or sorbitan monolaurate, or a cationic surfactant such as octadecylamine acetate. Furthermore, a polymerization initiator may be used, such as a peroxide such as t-butylperoxy-2-ethylhexanoate, potassium persulfate, or cumene peroxide, or an azo compound such as 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)-propionamide) or 2,2'-azobis(2-amidinopropane) hydrochloride.

[0072] The polymerization procedure is as follows: first, a monomer for forming the core part and an emulsifier are mixed and emulsion-polymerized all at once to obtain a particulate polymer for forming the core part. Then, a monomer for forming the shell part is polymerized in the presence of the particulate polymer for forming the core part, thereby obtaining a particulate polymer having the above-mentioned core-shell structure.

[0073] In this case, when preparing a particulate polymer in which the outer surface of the core part is partially covered with the shell part, it is preferable to supply the monomer that forms the polymer for the shell part to the polymerization system in multiple divided portions or continuously. By supplying the monomer that forms the polymer for the shell part to the polymerization system in divided portions or continuously, the polymer that forms the shell part is formed in a particulate form, and this particle is bonded to the core part, thereby forming the shell part that partially covers the core part.

[0074] <Particulate polymer without core-shell structure> <<Composition>> Monomers used to prepare the particulate polymer without a core-shell structure, which are optionally contained in the non-aqueous secondary battery adhesive layer composition of the present invention, include the same monomers as those exemplified as monomers that can be used to produce the core polymer of the particulate polymer having a core-shell structure described above. For example, as monomers used to prepare the particulate polymer without a core-shell structure, it is preferable to use (meth)acrylic acid ester monomers, aromatic vinyl monomers, acid group-containing monomers, crosslinkable monomers, etc. Note that such monomers may be used alone or in combination of two or more at any ratio.

[0075] From the viewpoint of further firmly bonding battery components together via an adhesive layer, the proportion of (meth)acrylic acid ester monomer units in the particulate polymer not having a core-shell structure is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, and is preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less, where all repeating units (total monomer units) contained in the polymer are 100% by mass.

[0076] From the viewpoint of further firmly bonding battery components together via an adhesive layer, the proportion of aromatic vinyl monomer units in the particulate polymer not having a core-shell structure is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, where all repeating units (total monomer units) contained in the polymer are 100% by mass.

[0077] The proportion of the acid group-containing monomer units in the particulate polymer having no core-shell structure is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the polymer. By keeping the proportion of the acid group-containing units in the particulate polymer having no core-shell structure within the above range, the dispersibility of the particulate polymer can be improved.

[0078] From the viewpoint of further firmly bonding battery components together via an adhesive layer, the proportion of crosslinkable monomer units in the particulate polymer not having a core-shell structure is preferably 0.2% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, with all repeating units (total monomer units) contained in the polymer being 100% by mass, preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less.

[0079] [Glass transition temperature] The glass transition temperature of the particulate polymer not having a core-shell structure is preferably -40°C or higher, more preferably -35°C or higher, even more preferably -30°C or higher, and preferably 0°C or lower, more preferably -10°C or lower, and even more preferably -20°C or lower. If the glass transition temperature of the particulate polymer not having a core-shell structure is -40°C or higher, the battery components can be more firmly bonded to each other via the adhesive material. On the other hand, if the glass transition temperature of the particulate polymer not having a core-shell structure is 0°C or lower, the particulate polymer can be prevented from falling off from the substrate.

[0080] [Volume average particle size] The volume average particle diameter of the particulate polymer not having a core-shell structure is preferably 50 nm or more, more preferably 100 nm or more, and even more preferably 200 nm or more, and is preferably 600 nm or less, more preferably 500 nm or less, and even more preferably 400 nm or less. When the volume average particle diameter of the particulate polymer not having a core-shell structure is within the above-mentioned range, the battery components can be more firmly bonded to each other via the adhesive material.

[0081] [Content] The content of the particulate polymer not having a core-shell structure in the composition for adhesive layer can be appropriately adjusted within a range in which the desired effects of the present invention can be obtained, but is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, per 100 parts by mass of the particulate polymer having a core-shell structure. When the content of the particulate polymer not having a core-shell structure is equal to or more than the above-mentioned lower limit, it is possible to suppress the particulate polymer from falling off from the substrate.

[0082] [Manufacturing method] The particulate polymer without core-shell structure is not particularly limited, and can be prepared, for example, by polymerizing a monomer composition containing the above-mentioned monomer in an aqueous solvent such as water.Here, the ratio of each monomer in the monomer composition is usually the same as the ratio of each monomer unit in the particulate polymer without core-shell structure.The polymerization method and polymerization reaction are not particularly limited, and known polymerization methods and polymerization reactions can be used.

[0083] <<Electrolyte swelling rate>> The swelling degree (hereinafter sometimes simply referred to as "swelling degree") of the particulate polymer in the electrolyte (a solution in which LiPF6 is dissolved at a concentration of 1 mol / L in a mixed solvent of ethylene carbonate / diethyl carbonate = 3 / 7 by volume ratio) is not particularly specified, but it is preferable that the particulate polymer does not dissolve in the electrolyte. If the particulate polymer dissolves, there is a concern that the battery characteristics may deteriorate. The degree of swelling of the particulate polymer in the electrolyte solution can be measured by the method described in the examples of this specification.

[0084] <Solvent> The solvent for dispersing the particulate polymer is not particularly limited, and can be, for example, water, an organic solvent, and a mixture thereof.The organic solvent is not particularly limited, and can be, for example, cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; ketones such as ethyl methyl ketone and cyclohexanone; esters such as ethyl acetate, butyl acetate, γ-butyrolactone and ε-caprolactone; nitriles such as acetonitrile and propionitrile; ethers such as tetrahydrofuran and ethylene glycol diethyl ether; alcohols such as methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, and ethylene glycol monomethyl ether. Among the above, it is preferable to use water from the viewpoint of simplifying the equipment. At least a part of the solvent may be removed by drying or the like in the manufacturing process of the non-aqueous secondary battery laminate.

[0085] <Other ingredients> Other components optionally contained in the nonaqueous secondary battery adhesive layer composition of the present invention include, but are not limited to, surface tension modifiers, dispersants different from the dispersant used in the polymerization, viscosity modifiers, reinforcing materials, electrolyte additives, and the like. These components are not particularly limited as long as they do not affect the battery reaction, and known components, such as those described in International Publication No. 2012 / 115096, can be used. These components may be used alone or in combination of two or more in any ratio.

[0086] <Properties of the composition for non-aqueous secondary battery adhesive layer> The composition for a non-aqueous secondary battery adhesive layer of the present invention preferably has a pressure sensitivity of adhesive strength calculated by the following formula (1) of more than 20 and less than 80. Pressure sensitivity of adhesive force (N / (m MPa)) = (T3-T1) / 2 (1) (In the formula, T1 represents the adhesive strength (N / m) between the polyethylene separator and the adhesive layer for a non-aqueous secondary battery obtained from the composition for a non-aqueous secondary battery adhesive layer when the two are pressure-bonded together at 25°C and a pressure of 1 MPa for 10 seconds, and T3 represents the adhesive strength (N / m) between the polyethylene separator and the adhesive layer for a non-aqueous secondary battery obtained from the composition for a non-aqueous secondary battery adhesive layer when the two are pressure-bonded together at 25°C and a pressure of 3 MPa for 10 seconds.)

[0087] The "pressure sensitivity of adhesive strength" calculated by the above formula (1) is the difference (T3 - T1) between the adhesive strength T3 (N / m) when a polyethylene separator and a non-aqueous secondary battery adhesive layer made using a non-aqueous secondary battery adhesive layer composition are pressure-bonded for 10 seconds at 25°C and a pressure of 3 MPa, and the adhesive strength T1 (N / m) when a polyethylene separator and a non-aqueous secondary battery adhesive layer obtained from a non-aqueous secondary battery adhesive layer composition are pressure-bonded for 10 seconds at 25°C and a pressure of 1 MPa. This difference is divided by the difference in pressure (MPa) during each pressure bonding (3 - 1 (= 2)). In other words, the pressure sensitivity of adhesive strength corresponds to the slope between pressures of 1 MPa and 3 MPa in a graph plotting the pressure during bonding on the horizontal axis and adhesive strength on the vertical axis, and represents the degree to which the adhesive strength when bonded under pressure of 3 MPa is greater than the adhesive strength when bonded under pressure of 1 MPa.

[0088] If the value is more than 20, it is possible to further improve the inkjet ejection characteristics and the adhesion between battery components when the battery components are bonded together under pressure at room temperature. If the value is less than 80, it is possible to suppress deformation of the particulate polymer due to the influence of internal pressure caused by swelling of the battery when a durability evaluation of the secondary battery is performed, thereby suppressing the occurrence of clogging of the separator and further improving the battery characteristics of the secondary battery. The "non-aqueous secondary battery adhesive layer" is a dried product of a non-aqueous secondary battery adhesive layer composition.

[0089] From the viewpoint of achieving a higher level of compatibility between the inkjet ejection characteristics, the adhesiveness between the battery components when bonded together by applying pressure at room temperature, and the battery characteristics of the secondary battery, the pressure sensitivity of the adhesive strength is preferably 30 or more, more preferably 40 or more, and even more preferably 48 or more, and is preferably 70 or less, and more preferably 60 or less.

[0090] The pressure sensitivity of the adhesive force can be controlled, for example, by changing the glass transition temperature of the core portion of the particulate polymer having a core-shell structure, the glass transition temperature of the shell portion, and / or the mass ratio of the shell portion to the total mass of the core portion and shell portion of the particulate polymer having a core-shell structure. The pressure sensitivity of the adhesive force can be measured by the method described in the Examples.

[0091] <Method for preparing a composition for a non-aqueous secondary battery adhesive layer> The method for preparing the nonaqueous secondary battery adhesive layer composition of the present invention is not particularly limited. For example, it can be prepared by stirring and mixing a particulate polymer having a core-shell structure, and optionally a particulate polymer not having a core-shell structure and / or other components in the presence of a solvent such as water. The stirring and mixing method is not particularly limited, and can be performed by a known method. Specifically, a general stirring vessel, ball mill, sand mill, bead mill, pigment disperser, ultrasonic disperser, crusher, homogenizer, planetary mixer, Filmix, etc. can be used. The mixing conditions are not particularly limited, but the mixture can typically be performed at a temperature between room temperature and 80°C for 10 minutes to several hours.

[0092] (Adhesive layer for non-aqueous secondary batteries) The adhesive layer for a non-aqueous secondary battery of the present invention is obtained using the composition for a non-aqueous secondary battery adhesive layer of the present invention. The adhesive layer for a non-aqueous secondary battery of the present invention functions as an adhesive material that bonds battery components used in a non-aqueous secondary battery together. The adhesive layer for a non-aqueous secondary battery of the present invention can be obtained, for example, by the method for producing an adhesive layer for a non-aqueous secondary battery of the present invention described below. The adhesive layer for a non-aqueous secondary battery of the present invention is a dried product obtained by drying the composition for a non-aqueous secondary battery adhesive layer of the present invention. Accordingly, the adhesive layer for a non-aqueous secondary battery of the present invention contains at least the particulate polymer having the core-shell structure described above, and optionally contains the particulate polymer not having the core-shell structure described above and / or other components.

[0093] Furthermore, the particulate polymer is present in particulate form in the composition for the adhesive layer for a non-aqueous secondary battery, but in the adhesive layer for a non-aqueous secondary battery, it may be in particulate form or any other form.

[0094] The shape of the adhesive layer is not particularly limited, and it can be formed into any shape in a plan view, such as a stripe shape, a dot shape, or a grid shape. From the viewpoint of reducing the resistance of the secondary battery, it is preferable to form the adhesive layer in a dot shape. The dot-shaped adhesive layer can be obtained by, for example, an inkjet method using a coater (51 to 54 in FIG. 2) described later.

[0095] The diameter of the dots in the adhesive layer arranged in a dot pattern is preferably 10 μm or more, more preferably 20 μm or more, and preferably 300 μm or less, more preferably 200 μm or less. If the diameter of the dots in the adhesive layer is equal to or greater than the lower limit, the adhesive strength between the electrode and the separator can be increased. On the other hand, if the diameter of the dots in the adhesive layer is equal to or less than the upper limit, a decrease in the output characteristics of the secondary battery can be suppressed.

[0096] The thickness of the dots of the adhesive layer arranged in a dot pattern is preferably 5 μm or more. If the thickness of the dots of the adhesive layer is equal to or greater than the above lower limit, the adhesive strength between the electrode and the separator can be increased.

[0097] The adhesive layer weight is 0.02 g / m 2 It is preferable that the content is 1.0 g / m or more. 2 Preferably, it is 0.35 g / m or less. 2 It is more preferable that the adhesive layer has a basis weight of at least the above lower limit, so that the adhesive strength between the electrode and the separator can be sufficiently ensured. Also, the adhesive layer has a basis weight of at most the above upper limit, so that the output characteristics of the secondary battery can be sufficiently high.

[0098] Furthermore, the coverage of the adhesive layer is preferably 1% or more, more preferably 5% or more, and preferably 50% or less, and more preferably 30% or less. If the coverage of the adhesive layer is above the lower limit, the adhesive strength between the electrode and the separator can be ensured. If the coverage of the adhesive layer is below the upper limit, the output characteristics of the secondary battery can be ensured to be sufficiently high.

[0099] Here, the "adhesive layer coverage" of a surface or region refers to the ratio of the area of ​​the portion covered by the adhesive layer to the total area of ​​the surface or region [(area of ​​the portion covered by the adhesive layer / total area of ​​the surface or region) x 100 (%)]. When a composition for an adhesive layer containing a particulate polymer and a solvent is used, the "adhesive layer" in the "coverage rate of the adhesive layer" refers to the dried product of the composition for an adhesive layer.

[0100] The coverage of the adhesive layer can be adjusted by changing the arrangement pattern of the adhesive layer arranged (coated) in each region. Specifically, if the adhesive layer is arranged (coated) in a dotted pattern in a certain region, the coverage of the adhesive layer in that region can be adjusted by changing the radius and center-to-center distance of the adhesive layer dots. For example, in a region where the adhesive layer is arranged (coated) in a dotted pattern in which dots are formed at regular intervals in two perpendicular directions, the coverage of the adhesive layer can be calculated using the center-to-center distances (pitch) x and y of the dots and the radius r of the dots using the following formula (2): Adhesive layer coverage = {πr 2 / (x y)}×100(%) (2)

[0101] (Method of manufacturing an adhesive layer for a non-aqueous secondary battery) The method for producing an adhesive layer for a non-aqueous secondary battery of the present invention includes a step of applying the composition for a non-aqueous secondary battery adhesive layer of the present invention onto the surface of a substrate by an inkjet method (coating step), and a step of drying the composition for a non-aqueous secondary battery adhesive layer applied to the substrate (drying step).The method for producing an adhesive layer for a non-aqueous secondary battery of the present invention may also include a step of peeling off the adhesive layer for a non-aqueous secondary battery formed on the substrate after the drying step (peeling step). When the adhesive layer for a non-aqueous secondary battery is formed on an electrode substrate or a separator substrate as a substrate, the electrode substrate and the separator substrate can be directly bonded to each other to form a laminate. When the adhesive layer for a non-aqueous secondary battery is formed on a release substrate as a substrate, the adhesive layer for a non-aqueous secondary battery can be used to bond the electrode substrate and the separator substrate after being peeled from the release agent.

[0102] <Coating process> In the coating step, droplets of the nonaqueous secondary battery adhesive layer composition of the present invention are applied onto a substrate such as an electrode substrate, separator substrate, or release substrate through the nozzle of an inkjet coater. Conventional inkjet coaters can be used, and coating can be performed using, for example, the coaters described below (51 to 54 in FIG. 2). From the viewpoint of production efficiency, it is preferable to coat the nonaqueous secondary battery adhesive layer composition onto an electrode substrate or separator substrate, and from the viewpoint of facilitating the drying step, it is preferable to coat the nonaqueous secondary battery adhesive layer composition onto an electrode substrate. The coating conditions using the inkjet method are not particularly limited as long as the non-aqueous secondary battery adhesive layer composition can be applied to a substrate, and can be adjusted appropriately depending on the desired shape of the resulting adhesive layer (planar view shape, dot diameter, dot thickness, dot pitch, coverage, basis weight, etc.).

[0103] <<Electrode base material>> The electrode substrate is not particularly limited and any known electrode substrate can be used. For example, the electrode substrate can be an electrode made of an electrode substrate formed by forming an electrode mixture layer on one or both sides of a current collector, or an electrode made by further forming a porous membrane layer on the electrode mixture layer of an electrode substrate. The current collector, electrode mixture layer, and porous membrane layer are not particularly limited, and any current collector, electrode mixture layer, and porous membrane layer that can be used in the field of secondary batteries, such as those described in JP 2013-145763 A, can be used.

[0104] <<Separator substrate>> The separator substrate is not particularly limited, and known separator substrates such as organic separator substrates can be used. The organic separator substrate is a porous member made of an organic material. Examples of organic separator substrates include microporous membranes or nonwoven fabrics containing polyolefin resins such as polyethylene and polypropylene, or aromatic polyamide resins, and polyethylene microporous membranes and nonwoven fabrics are preferred because of their excellent strength. From the viewpoint of safety, a heat-resistant separator in which ceramic is applied to the separator is also preferred. The separator substrate may have a porous membrane layer formed on one or both sides thereof. The porous membrane layer refers to a layer containing non-conductive particles, such as those described in JP 2013-145763 A.

[0105] <<Release base material>> The release substrate is not particularly limited, and any known substrate can be used.

[0106] <Drying process> In the drying step, the adhesive layer composition coated on the substrate is dried to form an adhesive layer on the substrate, the adhesive layer being made of the dried adhesive layer composition. The drying method is not particularly limited, and known methods can be used. Examples of drying methods include drying methods using a heating device such as a heater, a dryer, or a heat roller. The drying conditions are not particularly limited, but the drying temperature is preferably 50°C or higher and 90°C or lower, and the drying time is preferably 1 second or higher and 120 seconds or lower.

[0107] <Peeling process> In the peeling step, the adhesive layer for a non-aqueous secondary battery formed on the substrate is peeled off. When the adhesive layer for a non-aqueous secondary battery is formed on a release substrate, the adhesive layer can be peeled off from the release substrate and used, for example, to produce a laminate for a non-aqueous secondary battery, which will be described later.

[0108] (Laminate for non-aqueous secondary battery) The non-aqueous secondary battery laminate of the present invention includes an electrode and a separator, and the electrode and the separator are bonded together via the adhesive layer for a non-aqueous secondary battery of the present invention. The electrode bonded to the separator to form the non-aqueous secondary battery laminate may be a positive electrode only, a negative electrode only, or both a positive electrode and a negative electrode. When both a positive electrode and a negative electrode are bonded to a separator to obtain the non-aqueous secondary battery laminate, the number of positive electrodes, negative electrodes, and separators in the non-aqueous secondary battery laminate may each be one, or two or more. That is, the structure of the non-aqueous secondary battery laminate of the present invention may be any of the following structures (1) to (6). (1) Positive electrode / separator (2) Negative electrode / separator (3) Positive electrode / separator / negative electrode (4) Positive electrode / separator / negative electrode / separator (5) Separator / positive electrode / separator / negative electrode (6) A structure in which multiple positive and negative electrodes are alternately stacked with separators in between (e.g., "separator / negative electrode / separator / positive electrode / separator / negative electrode... / separator / positive electrode").

[0109] <Electrode> The electrode is not particularly limited, and known electrodes can be used, for example, those described in the section "Method for producing an adhesive layer for a non-aqueous secondary battery" can be used.

[0110] <Separator> The separator is not particularly limited, and any known separator can be used, such as those described in the section "Method for producing adhesive layer for non-aqueous secondary battery."

[0111] <Adhesive layer> As described above, the adhesive layer that bonds the electrode and the separator is a dried product of the composition for an adhesive layer for a non-aqueous secondary battery of the present invention. That is, the dried product contains at least a polymer derived from the particulate polymer and optionally contains other components described above. The preferred form of the adhesive layer (dot diameter, dot thickness, dot pitch, coverage, basis weight, etc.) is the same as that explained in the <Adhesive layer for non-aqueous secondary battery> section. Furthermore, the particulate polymer is present in particulate form in the composition for a non-aqueous secondary battery adhesive layer, but may be in particulate form or any other form in the adhesive layer for a non-aqueous secondary battery in the laminate.

[0112] (Method of manufacturing a laminate for a non-aqueous secondary battery) The method for producing a laminate for a nonaqueous secondary battery of the present invention includes a step of supplying an adhesive material to at least one bonding surface of an electrode and a separator (i.e., the surface on which the adhesive material (adhesive layer) is formed) (supplying step), and a step of bonding the electrode and the separator together by applying pressure at room temperature via the bonding surface to which the adhesive material has been supplied (bonding step). Furthermore, the method for producing a laminate for a nonaqueous secondary battery of the present invention may include a step of cutting the resulting bonded body after the bonding step (cutting step).

[0113] <Supply process> In the supplying step, an adhesive material is supplied to the bonding surface of at least one of the electrodes (positive electrode, negative electrode) and the separator. The adhesive material can be supplied by applying the nonaqueous secondary battery adhesive layer composition of the present invention by an inkjet method and drying it. Alternatively, the adhesive material can be supplied by transferring (laminating) the nonaqueous secondary battery adhesive layer obtained by peeling it from the release substrate as described above onto the bonding surface.

[0114] The conditions for the inkjet method are not particularly limited as long as the non-aqueous secondary battery adhesive layer composition can be applied, and can be adjusted appropriately depending on the desired form of the resulting adhesive material (planar view shape, dot diameter, dot thickness, dot pitch, coverage, basis weight, etc.).

[0115] When the non-aqueous secondary battery adhesive layer composition is applied by an inkjet method, the electrode and separator can be transported to the lamination start position without contacting other components with the lamination surface to which the non-aqueous secondary battery adhesive layer composition has been applied, and the non-aqueous secondary battery adhesive layer composition can be dried during transport. Since no other components come into contact with the lamination surface to which the non-aqueous secondary battery adhesive layer composition has been applied, problems such as blocking do not occur, allowing for efficient production of secondary battery laminates. When a non-aqueous secondary battery adhesive layer obtained by peeling it from a release substrate is applied, drying is not required. In the present invention, the "bonding start position" refers to the position where the bonding surface of the electrode and the bonding surface of the separator come into contact when bonding the electrode and the separator together.

[0116] The electrodes and separators may be transported using any transport mechanism, such as, for example, rollers, belt conveyors, manipulators, suction bands, etc. Among these, from the viewpoint of further improving the production efficiency of the laminate for secondary batteries, it is preferable to transport at least one of the electrodes and the separator using rollers.

[0117] The drying of the non-aqueous secondary battery adhesive layer composition can be carried out using a heating device such as a heater, a dryer, or a heat roller, without any particular limitation. The temperature at which the electrode and / or separator to which the non-aqueous secondary battery adhesive layer composition is supplied is dried is not particularly limited, but is preferably 50° C. or higher and 90° C. or lower. The drying time is not particularly limited, but is preferably 1 second or higher and 120 seconds or lower.

[0118] <Laminating process> In the bonding step, the electrode and the separator are bonded together via their bonding surfaces by applying pressure to a laminate of the electrode and the separator, which are stacked together via their bonding surfaces, at room temperature.

[0119] The pressure to be applied to the laminate can be adjusted appropriately depending on the type and amount of the particulate polymer used, but is preferably more than 1 MPa and not more than 5 MPa.

[0120] <Cutting process> The cutting step is a step of cutting the laminate obtained in the laminating step into desired dimensions. For cutting, any cutter that can be used in the field of secondary battery manufacturing can be used, such as a cutter that sandwiches the laminate with cutting blades from both sides in the thickness direction of the laminate to cut it.

[0121] <<Electrodes and separators>> The electrodes and separators are not particularly limited, and known electrodes and separators can be used, for example, the electrodes and separators described above in the section "Method for producing an adhesive layer for a non-aqueous secondary battery."

[0122] <<Adhesive material>> The adhesive material for bonding an electrode and a separator is a dried product of the composition for an adhesive layer for a non-aqueous secondary battery of the present invention, that is, the dried product contains at least a polymer derived from the particulate polymer and optionally contains other components described above. The preferred form of the adhesive material (dot diameter, dot thickness, dot pitch, coverage, basis weight, etc.) is the same as that explained in the <Adhesive layer for non-aqueous secondary battery> section. Furthermore, the particulate polymer is present in particulate form in the composition for a non-aqueous secondary battery adhesive layer, but may be in particulate form or any other form in the non-aqueous secondary battery adhesive layer of the laminate after pressing.

[0123] An example of the process for producing the non-aqueous secondary battery laminate of the present invention will be described below with reference to FIG. Referring to FIG. 2, a long first separator blank 10A unwound from a first separator blank roll is bonded to one surface of a long negative electrode blank 20A unwound from a negative electrode blank roll, with an adhesive material supplied from a coater 51. At the same time, a long second separator blank 30A unwound from a second separator blank roll is bonded to the other surface of the negative electrode material 20A with an adhesive material supplied from a coater 52. The bonding can be performed using, for example, pressure rollers 61 and 62. Then, positive electrodes 40 are bonded at a predetermined arrangement pitch to the surface of the first separator blank 10A opposite to the negative electrode blank 20A side with the adhesive material supplied from a coater 53, to obtain a bonded body including positive electrodes. 2, an adhesive material is supplied from a coater 54 to the surface of the second separator raw roll 30A opposite to the negative electrode raw roll 20A side, and the laminate is cut between longitudinally adjacent positive electrodes 40 to obtain a laminate, which is then stacked to produce the laminate. The laminate is then cut using a cutter 70 to obtain a laminate.

[0124] (Non-aqueous secondary battery) The nonaqueous secondary battery of the present invention includes the nonaqueous secondary battery laminate of the present invention. The nonaqueous secondary battery of the present invention includes, for example, electrodes (positive electrode and negative electrode), an electrolyte, and a separator. At least one of the positive electrode and the negative electrode and the separator are bonded together via the nonaqueous secondary battery adhesive layer of the present invention to form the nonaqueous secondary battery laminate of the present invention. Because the nonaqueous secondary battery of the present invention includes the nonaqueous secondary battery laminate of the present invention, it can exhibit excellent battery characteristics.

[0125] <Electrode> The electrode used in the secondary battery of the present invention is not limited, and known electrodes can be used, for example, those described in the section "Method for producing an adhesive layer for a non-aqueous secondary battery."

[0126] <Separator> The separator used in the secondary battery of the present invention is not limited, and any known separator can be used, for example, the separator described in the section "Method for producing adhesive layer for non-aqueous secondary battery" can be used.

[0127] <Electrolyte> The electrolyte solution 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, when the nonaqueous secondary battery is a lithium ion secondary battery, a lithium salt is used as the supporting electrolyte. Examples of lithium salts include LiPF6, LiAsF6, LiBF4, LiSbF6, LiAlCl4, LiClO4, CF3SO3Li, CF4F9SO3Li, CF3COOLi, (CF3CO)2NLi, (CF3SO2)2NLi, and (C2F5SO2)NLi. Among these, LiPF6, LiClO4, and CF3SO3Li are preferred, with LiPF6 being particularly preferred, because they are easily soluble in solvents and exhibit a high degree of dissociation. Note that one type of electrolyte may be used alone, or two or more types may be used in combination in any ratio. Typically, the use of a supporting electrolyte with a higher degree of dissociation tends to result in higher lithium ion conductivity, so the lithium ion conductivity can be adjusted by the type of supporting electrolyte.

[0128] The organic solvent used in the electrolyte is not particularly limited as long as it can dissolve the supporting electrolyte. Suitable examples include carbonates such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), and ethyl methyl carbonate (EMC); esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; and sulfur-containing compounds such as sulfolane and dimethyl sulfoxide. Mixtures of these solvents may also be used. Among these, carbonates are preferred because of their high dielectric constant and wide stable potential range. A mixture of ethylene carbonate and ethyl methyl carbonate is even more preferred. The electrolyte may also contain known additives such as vinylene carbonate (VC), fluoroethylene carbonate (FEC), and ethyl methyl sulfone.

[0129] (Secondary battery manufacturing method) The secondary battery of the present invention can be produced, for example, by stacking laminates to form a stack, which can then be rolled or folded, as necessary, according to the battery shape, placed in a device container (battery container), and then injecting an electrolyte into the device container and sealing it. The stack may be the laminate itself, or a plurality of laminates may be stacked together. The stack may also be produced by stacking a laminate with additional battery components (electrodes and / or separators, etc.). The secondary battery of the present invention may also be provided with a fuse, an overcurrent protection element such as a PTC element, an expanded metal, a lead plate, etc., as necessary to prevent internal pressure buildup, overcharging and overdischarging, etc. The secondary battery may have any shape, such as a coin type, a button type, a sheet type, a cylindrical type, a rectangular type, or a flat type. [Example]

[0130] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. In the following description, "%" and "parts" representing amounts are based on mass unless otherwise specified. Furthermore, in a polymer produced by copolymerizing multiple types of monomers, the proportion of a monomer unit formed by polymerizing a certain monomer in the polymer usually coincides with the ratio (feed ratio) of the certain monomer to all the monomers used in the polymerization of the polymer, unless otherwise specified. Various measurements and evaluations in the examples and comparative examples were carried out by the following methods.

[0131] <Glass transition temperature> The aqueous dispersion of particulate polymer prepared in each production example was dried at 130°C for 1 hour to prepare a sample. A 10 mg sample was weighed into an aluminum pan and measured using a differential scanning calorimetry (DSC) analyzer (SII NanoTechnology, Inc., EXSTAR DSC6220) at a temperature range of -100°C to 200°C at a heating rate of 10°C / min according to the conditions specified in JIS Z8703. A differential scanning calorimetry (DSC) curve was obtained. An empty aluminum pan was used as a reference. The glass transition temperature (°C) was determined by the intersection of the baseline just before the endothermic peak of the DSC curve, where the differential signal (DDSC) is 0.05 mW / min / mg or greater, and the tangent to the DSC curve at the first inflection point after the endothermic peak.

[0132] <Volume average particle size> The volume average particle diameter of the particulate polymer prepared in each production example was measured by laser diffraction. Specifically, an aqueous dispersion solution (solid content concentration 0.1 mass%) containing the prepared particulate polymer was used as a sample, and the particle size distribution (volume basis) obtained using a laser diffraction particle size distribution analyzer (manufactured by Beckman Coulter, product name "LS-13 320") was used to obtain the particle diameter at which the cumulative volume calculated from the smallest diameter side reached 50%, which was defined as the volume average particle diameter D50 (nm).

[0133] <Electrolyte swelling rate> The aqueous dispersion of particulate polymer prepared in each production example was dried, and approximately 0.2 g of the resulting dried product was pressed for 2 minutes at a temperature of 200°C and a pressure of 5 MPa to obtain a film. The obtained film was cut into 1 cm squares to prepare test pieces, and the mass W1 (g) of each test piece was measured. Next, the test piece was immersed in an electrolyte (a solution in which LiPF6 was dissolved at a concentration of 1 mol / L in a mixed solvent of ethylene carbonate / diethyl carbonate = 3 / 7 by volume ratio) at a temperature of 60°C for 72 hours. Thereafter, the test piece was removed from the electrolyte, the mixed solvent on the surface was wiped off, and the mass W2 (g) of the test piece was measured. The swelling degree (%) was then calculated according to the following formula: Electrolyte swelling rate (%) = W2 / W1 x 100

[0134] <Weight of adhesive layer> The basis weight of the adhesive layer was determined from the difference in mass per unit area before the adhesive layer composition was supplied on the substrate and after the adhesive layer composition was supplied and dried.

[0135] <Adhesive layer coverage> Using a laser microscope (Keyence Corporation, VR-3100), the center-to-center distances (pitch) x and y of the dots and the radius r of the dots were measured in the area where the adhesive material was applied in a dot pattern.Then, using these values, the coverage of the adhesive layer was calculated using the following formula (2). Adhesive layer coverage = {πr 2 / (x y)}×100(%) (2)

[0136] <Pressure sensitivity of adhesive force> The non-aqueous secondary battery adhesive layer composition produced in each example and comparative example was applied to the rough surface of a PET substrate (Unitika polyester film PTHA-25) using a bar coater, and then dried at 50°C for 2 minutes, resulting in a coating weight of 4 to 5 g / m on the PET substrate after drying. 2 A thin film of this material was formed. It was then punched out to a size of 10 x 50 mm and then placed on a 25 x 60 mm cut PE separator (ND412 manufactured by Asahi Kasei, surface roughness Sa: 0.10-0.20 μm). This was then pressed in a precision press at a temperature of 25°C, a pressure of 1 MPa, and a pressing time of 10 seconds to obtain an evaluation sample. The evaluation sample was then fixed with the PE separator side attached to the base of a peel tester (load cell) with double-sided tape, and the PET substrate was pulled at a peel angle of 90° at a rate of 50 mm / min to measure the peel strength. The peel strength was also measured in the same way for the evaluation sample that had been precision pressed at a temperature of 25°C, a pressure of 3 MPa, and a pressing time of 10 seconds. The difference between the peel strength when pressed at a pressure of 3 MPa and the peel strength when pressed at a pressure of 1 MPa, divided by 2, was used as the "pressure sensitivity."

[0137] <Inkjet ejection characteristics> The non-aqueous secondary battery adhesive layer compositions prepared in each Example and Comparative Example were subjected to a discharge test using a high-performance head-mounted discharge test kit (IJK-200S, manufactured by Microjet Co., Ltd.), and the discharge characteristics were evaluated according to the following criteria. A: It can be dispensed and can be re-discharged even if left standing for 5 minutes or more. B: Dischargeable, but unable to be re-discharged after 5 minutes of standing C: Unable to discharge

[0138] <Adhesion strength between electrode and separator> Under the same conditions as in each example and comparative example, a negative electrode coated with an adhesive layer (adhesive material) on one side and a separator were pressed for 10 seconds under pressing conditions of a temperature of 25°C and a pressure of 2 MPa, and the laminate after bonding (i.e., a laminate formed by bonding one negative electrode and one separator via the adhesive material) was collected and used as a test piece. The test piece was placed with the negative electrode current collector side facing downward, and cellophane tape was attached to the surface of the negative electrode current collector side. The cellophane tape used was specified in JIS Z1522. The cellophane tape was fixed to a horizontal test table. One end of the separator was then pulled vertically upward at a pulling rate of 50 mm / min, and the stress when peeled off was measured. This measurement was performed a total of six times, and the average stress value was calculated as the peel strength, and the adhesion between the negative electrode and the separator was evaluated according to the following criteria: A higher peel strength indicates a higher adhesion between the electrode (negative electrode) and the separator. A: Peel strength is 5.0N / m or more B: Peel strength is 3.0 N / m or more and less than 5.0 N / m C: Peel strength is 0.5N / m or more and less than 3.0N / m D: Peel strength is 0.3 N / m or more and less than 0.5 N / m E: Peel strength is less than 0.3 N / m

[0139] <Lithium deposition rate on the negative electrode surface> The manufactured lithium-ion secondary battery was fully charged to a depth of charge (SOC) of 100% at a constant current of 1 C in an environment at a temperature of -10°C. The fully charged secondary battery was disassembled, the negative electrode was removed, and the surface condition of the negative electrode composite layer of the negative electrode was observed. The area of ​​lithium deposited on the surface of the negative electrode composite layer was then measured, and the lithium deposition rate on the negative electrode surface = (area of ​​deposited lithium / surface area of ​​the negative electrode composite layer) × 100 (%) was calculated. Evaluation was then performed according to the following criteria. A lower lithium deposition rate on the negative electrode surface indicates that lithium deposition on the negative electrode surface during charging is more suppressed. A: Lithium deposition rate is less than 10% B: Lithium deposition rate is 10% or more and less than 15% C: Lithium deposition rate is 15% or more and less than 20% D: Lithium deposition rate is 20% or more

[0140] <Output characteristics> The fabricated lithium-ion secondary battery was charged at constant current and constant voltage (CCCV) up to 4.3 V in an atmosphere at 25°C to prepare a cell. The prepared cell was discharged to 3.0 V at constant currents of 0.2 C and 1 C in an atmosphere at -10°C to determine the electric capacity. The discharge capacity retention rate, expressed as the ratio of electric capacities (= (electric capacity at 1 C / electric capacity at 0.2 C) × 100 (%)), was then determined. These measurements were performed on five lithium-ion secondary battery cells, and the average value of the determined discharge capacity retention rate was evaluated as the output characteristics according to the following criteria. A higher value indicates better output characteristics. A: The average discharge capacity retention rate is 80% or more B: The average discharge capacity retention rate is 70% or more and less than 80% C: The average discharge capacity retention rate is 60% or more and less than 70% D: The average discharge capacity retention rate is less than 60%

[0141] <Resistance increase during cycle testing> The fabricated lithium-ion secondary batteries were clamped using a pressure jig to a surface pressure of 1 MPa, and then subjected to a cycle test at 45°C. The cycle test conditions were 1C CC+CV charge (4.3V, 1 / 50C cut) and 1C CC discharge (3.0V cut), and the charge / discharge cycle was repeated 500 times. The temperature was then lowered to 25°C while still clamped using the pressure jig, and the output characteristics were measured in the same manner as in the above <Output Characteristics>. The resistance retention rate (%) before and after the cycle (= discharge capacity retention rate after cycle test / discharge capacity retention rate before cycle test × 100) was calculated and evaluated according to the following criteria. A higher resistance retention rate before and after the cycle indicates a smaller increase in resistance during the cycle test. A: Resistance retention rate is 80% or more B: Resistance maintenance rate is 60% or more but less than 80% C: Resistance maintenance rate is 40% or more but less than 60% D: Resistance maintenance rate is less than 40%

[0142] (Production Example 1) <Production of Particulate Polymer 1> A reactor equipped with a stirrer was charged with 100 parts of ion-exchanged water, 0.3 parts of ammonium persulfate, and 0.02 parts of sodium dodecylbenzenesulfonate (Kao Chemical Corporation, "Neopelex G-15") as an emulsifier. The gas phase was replaced with nitrogen gas and the temperature was raised to 80°C. Meanwhile, in a separate vessel, 40 parts of ion-exchanged water, 0.2 parts of sodium dodecylbenzenesulfonate as an emulsifier, 27.4 parts of styrene as an aromatic monovinyl monomer, 64.5 parts of 2-ethylhexyl acrylate as a monofunctional (meth)acrylic acid ester monomer, 3 parts of methacrylic acid as an acidic group-containing monomer, and 0.1 parts of ethylene glycol dimethacrylate as a crosslinkable monomer were mixed to obtain a core-forming monomer composition. This core-forming monomer composition was continuously added to the reactor over a period of 3 hours, and a polymerization reaction was carried out at 80°C. Polymerization was continued until the polymerization conversion reached 95%, yielding an aqueous dispersion containing a particulate polymer constituting the core. Next, a shell-forming monomer composition containing 4.1 parts of styrene as an aromatic monovinyl monomer, 0.8 parts of methoxypolyethylene glycol methacrylate (product name "NK Ester M90G", manufactured by Shin-Nakamura Chemical Co., Ltd.) as an alkylene oxide group-containing monomer unit, and 0.1 parts of methacrylic acid as an acid group-containing monomer was continuously added to this aqueous dispersion over 60 minutes, and polymerization was continued. When the polymerization conversion reached 98%, the reaction was stopped by cooling, yielding an aqueous dispersion containing particulate polymer 1. The volume average particle size, swelling degree, and glass transition temperature of the obtained particulate polymer 1 were measured. The results are shown in Table 1. Furthermore, by observing the cross-sectional structure of the particulate polymer using a transmission electron microscope (TEM), it was confirmed that the particulate polymer has a core-shell structure in which the shell part partially covers the outer surface of the core part.

[0143] (Production Example 2) <Production of Particulate Polymer 2> In the production of the particulate polymer of Production Example 1, an aqueous dispersion of particulate polymer 2 having a core-shell structure was prepared in the same manner as in Production Example 1, except that instead of the shell-forming monomer composition containing 4.1 parts of styrene as the aromatic monovinyl monomer, 0.8 parts of methoxypolyethylene glycol methacrylate as the alkylene oxide group-containing monomer unit, and 0.1 parts of methacrylic acid as the acidic group-containing monomer, a shell-forming monomer composition containing 2.4 parts of styrene as the aromatic monovinyl monomer, 2.5 parts of methoxypolyethylene glycol methacrylate as the alkylene oxide group-containing monomer, and 0.1 parts of methacrylic acid as the acidic group-containing monomer was used. Then, various measurements were performed in the same manner as in Production Example 1. The results are shown in Table 1.

[0144] (Production Example 3) <Production of Particulate Polymer 3> In the production of the particulate polymer of Production Example 1, an aqueous dispersion of particulate polymer 3 having a core-shell structure was prepared in the same manner as in Production Example 1, except that instead of the shell-forming monomer composition containing 4.1 parts of styrene as the aromatic monovinyl monomer, 0.8 parts of methoxypolyethylene glycol methacrylate as the alkylene oxide group-containing monomer unit, and 0.1 parts of methacrylic acid as the acidic group-containing monomer, a shell-forming monomer composition containing 4.65 parts of styrene as the aromatic monovinyl monomer, 0.25 parts of methoxypolyethylene glycol methacrylate as the alkylene oxide group-containing monomer, and 0.1 parts of methacrylic acid as the acidic group-containing monomer was used. Then, various measurements were performed in the same manner as in Production Example 1. The results are shown in Table 1.

[0145] (Production Example 4) <Production of Particulate Polymer 4> In the production of the particulate polymer of Production Example 1, an aqueous dispersion of particulate polymer 4 having a core-shell structure was prepared in the same manner as in Production Example 1, except that instead of the shell-forming monomer composition containing 4.1 parts of styrene as an aromatic monovinyl monomer, 0.8 parts of methoxypolyethylene glycol methacrylate as an alkylene oxide group-containing monomer unit, and 0.1 parts of methacrylic acid as an acidic group-containing monomer, a shell-forming monomer composition containing 4.1 parts of styrene as an aromatic monovinyl monomer, 0.8 parts of methoxypolyethylene glycol acrylate (product name "NK Ester AM90G", manufactured by Shin-Nakamura Chemical Co., Ltd.) as an alkylene oxide group-containing monomer, and 0.1 parts of methacrylic acid as an acidic group-containing monomer was used. The results were then obtained in the same manner as in Production Example 1.

[0146] (Production Example 5) <Production of Particulate Polymer 5> In the production of the particulate polymer of Production Example 1, instead of the core-forming monomer composition containing 27.4 parts of styrene as an aromatic monovinyl monomer, 64.5 parts of 2-ethylhexyl acrylate as a monofunctional (meth)acrylic acid ester monomer, 3 parts of methacrylic acid as an acidic group-containing monomer, and 0.1 parts of ethylene glycol dimethacrylate as a crosslinkable monomer, a core-forming monomer composition containing 17.8 parts of styrene as an aromatic monovinyl monomer, 49.1 parts of 2-ethylhexyl acrylate as a monofunctional (meth)acrylic acid ester monomer, 3 parts of methacrylic acid as an acidic group-containing monomer, and 0.1 parts of ethylene glycol dimethacrylate as a crosslinkable monomer was used. An aqueous dispersion of particulate polymer 5 having a core-shell structure was prepared in the same manner as in Production Example 1, except that the monomer composition for forming the core portion was used, and a monomer composition for forming the shell portion containing 25 parts of styrene as an aromatic monovinyl monomer, 4 parts of methoxypolyethylene glycol methacrylate as an alkylene oxide group-containing monomer, and 1 part of methacrylic acid as an acidic group-containing monomer was used instead of the monomer composition for forming the shell portion containing 4.1 parts of styrene as an aromatic monovinyl monomer, 0.8 parts of methoxypolyethylene glycol methacrylate as an alkylene oxide group-containing monomer, and 0.1 parts of methacrylic acid as an acidic group-containing monomer. Various measurements were then performed in the same manner as in Production Example 1. The results are shown in Table 1.

[0147] (Production Example 6) <Production of Particulate Polymer 6> In the production of the particulate polymer of Production Example 1, an aqueous dispersion of particulate polymer 6 having a core-shell structure was prepared in the same manner as in Production Example 1, except that instead of the core-forming monomer composition containing 27.4 parts of styrene as the aromatic monovinyl monomer, 64.5 parts of 2-ethylhexyl acrylate as the monofunctional (meth)acrylic acid ester monomer, 3 parts of methacrylic acid as the acidic group-containing monomer, and 0.1 parts of ethylene glycol dimethacrylate as the crosslinkable monomer, a core-forming monomer composition containing 18.5 parts of styrene as the aromatic monovinyl monomer, 72.6 parts of butyl acrylate as the monofunctional (meth)acrylic acid ester monomer, 2.9 parts of methacrylic acid as the acidic group-containing monomer, and 1 part of ethylene glycol dimethacrylate as the crosslinkable monomer was used. Various measurements were then performed in the same manner as in Production Example 1. The results are shown in Table 1.

[0148] (Production Example 7) <Production of Particulate Polymer 7> In the production of the particulate polymer of Production Example 1, an aqueous dispersion of particulate polymer 7 having a core-shell structure was prepared in the same manner as in Production Example 1, except that instead of the core-forming monomer composition containing 27.4 parts of styrene as the aromatic monovinyl monomer, 64.5 parts of 2-ethylhexyl acrylate as the monofunctional (meth)acrylic acid ester monomer, 3 parts of methacrylic acid as the acidic group-containing monomer, and 0.1 parts of ethylene glycol dimethacrylate as the crosslinkable monomer, a core-forming monomer composition containing 72.4 parts of butyl acrylate and 18.7 parts of methyl methacrylate as the monofunctional (meth)acrylic acid ester monomer, 2.9 parts of methacrylic acid as the acidic group-containing monomer, and 1 part of ethylene glycol dimethacrylate as the crosslinkable monomer was used. Various measurements were then performed in the same manner as in Production Example 1. The results are shown in Table 1.

[0149] (Production Example 8) <Production of Particulate Polymer 8> In the production of the particulate polymer of Production Example 1, an aqueous dispersion of particulate polymer 8 having a core-shell structure was prepared in the same manner as in Production Example 1, except that instead of the core-forming monomer composition containing 27.4 parts of styrene as the aromatic monovinyl monomer, 64.5 parts of 2-ethylhexyl acrylate as the monofunctional (meth)acrylic acid ester monomer, 3 parts of methacrylic acid as the acidic group-containing monomer, and 0.1 parts of ethylene glycol dimethacrylate as the crosslinkable monomer, a core-forming monomer composition containing 17.4 parts of styrene as the aromatic monovinyl monomer, 64.5 parts of 2-ethylhexyl acrylate as the monofunctional (meth)acrylic acid ester monomer, 10 parts of acrylonitrile as the (meth)acrylonitrile monomer, 3 parts of methacrylic acid as the acidic group-containing monomer, and 0.1 parts of ethylene glycol dimethacrylate as the crosslinkable monomer was used. The results were then obtained by carrying out various measurements in the same manner as in Production Example 1. Table 1 shows the results.

[0150] (Production Example 9) <Production of Particulate Polymer 9> 90 parts of ion-exchanged water and 0.5 parts of ammonium persulfate were fed into a reactor equipped with a stirrer, the gas phase was replaced with nitrogen gas, and the temperature was raised to 80° C. Meanwhile, in a separate vessel, 15 parts of ion-exchanged water, 1.0 part of sodium dodecylbenzenesulfonate (Kao Chemical Corporation, "Neopelex G-15") as an emulsifier, 70.0 parts of 2-ethylhexyl acrylate as a monofunctional (meth)acrylic acid ester monomer, 25.0 parts of styrene as an aromatic monovinyl monomer, 1.7 parts of allyl glycidyl ether and 0.3 parts of allyl methacrylate as crosslinkable monomers, and 3.0 parts of acrylic acid as an acidic group-containing monomer were mixed to obtain a monomer composition. This monomer composition was continuously added to the reactor over 4 hours to carry out polymerization. During the continuous addition, the reaction was carried out at a temperature of 80° C. After the continuous addition was completed, the mixture was stirred at 80° C. for an additional 3 hours to complete the reaction. The obtained aqueous dispersion was cooled to a temperature of 25°C, and then an aqueous sodium hydroxide solution was added thereto to adjust the pH to 8.0. Thereafter, steam was introduced to remove unreacted monomers, thereby obtaining an aqueous dispersion of particulate polymer 9 not having a core-shell structure. Various measurements were then carried out in the same manner as in Production Example 1. The results are shown in Table 1.

[0151] (Production Example 10) <Production of Particulate Polymer 10> To a reactor equipped with a stirrer, 90 parts of ion-exchanged water, 0.05 parts of sodium dodecylbenzenesulfonate (manufactured by Kao Chemical Corporation, "Neopelex G-15") as an emulsifier, and 0.23 parts of ammonium persulfate were supplied, the gas phase was replaced with nitrogen gas, and the temperature was raised to 70°C. Separately, in a separate container, 50 parts of ion-exchanged water, 0.1 parts of sodium dodecylbenzenesulfonate (Kao Chemical Corporation, "Neopelex G-15") as an emulsifier, 2.5 parts of methacrylic acid (MAA) as an acidic functional group-containing monomer, 10 parts of acrylonitrile (AN) as a (meth)acrylonitrile monomer, 85.3 parts of n-butyl acrylate (BA) as a monofunctional (meth)acrylic acid ester monomer, 0.2 parts of allyl methacrylate (AMA) as a crosslinkable monomer, and 2.0 parts of acrylamide (Aam) as a (meth)acrylamide monomer were mixed to obtain a monomer composition. This monomer composition was continuously added to the reactor over 4 hours to carry out polymerization. The reaction was carried out at 80°C during the addition. After the addition was completed, the mixture was stirred for an additional 3 hours at 80°C to terminate the reaction, producing an aqueous dispersion containing a particulate polymer 10 not having a core-shell structure. Various measurements were then carried out in the same manner as in Production Example 1. The results are shown in Table 1.

[0152] (Comparative Manufacturing Example 1) <Production of Particulate Polymer 11> In the production of the particulate polymer of Production Example 5, an aqueous dispersion of particulate polymer 11 having a core-shell structure was prepared in the same manner as in Production Example 5, except that instead of the monomer composition for forming a shell portion containing 4.1 parts of styrene as an aromatic monovinyl monomer, 0.8 parts of methoxypolyethylene glycol methacrylate as an alkylene oxide group-containing monomer, and 0.1 parts of methacrylic acid as an acidic group-containing monomer, a monomer composition for forming a shell portion containing 29 parts of styrene as an aromatic monovinyl monomer and 1 part of methacrylic acid as an acidic group-containing monomer was used. Then, various measurements were carried out in the same manner as in Production Example 1. The results are shown in Table 1.

[0153] (Comparative Manufacturing Example 2) <Production of Particulate Polymer 12> In the production of the particulate polymer of Production Example 1, instead of the core-forming monomer composition containing 27.4 parts of styrene as the aromatic monovinyl monomer, 64.5 parts of 2-ethylhexyl acrylate as the monofunctional (meth)acrylic acid ester monomer, 3 parts of methacrylic acid as the acidic group-containing monomer, and 0.1 parts of ethylene glycol dimethacrylate as the crosslinkable monomer, a core-forming monomer composition containing 28.9 parts of styrene as the aromatic monovinyl monomer, 68 parts of 2-ethylhexyl acrylate as the monofunctional (meth)acrylic acid ester monomer, 3 parts of methacrylic acid as the acidic group-containing monomer, and 0.1 parts of ethylene glycol dimethacrylate as the crosslinkable monomer was used, and an aqueous dispersion of particulate polymer 12 not having a core-shell structure was prepared in the same manner as in Production Example 1, except that the shell-forming monomer composition was not supplied. Then, various measurements were performed in the same manner as in Production Example 1. The results are shown in Table 1.

[0154] Example 1 <Preparation of Adhesive Layer Composition> The aqueous dispersion of particulate polymer 1 obtained in Production Example 1 and the aqueous dispersion of particulate polymer 9 obtained in Production Example 9 were mixed so that the mass ratio of the solid contents was 100:10, and then ion-exchanged water was added to dilute the mixture so that the solid content concentration was 10.5%. Propylene glycol was further added to the obtained mixture to adjust the solid content concentration to 10%, thereby obtaining a composition for adhesive layer.

[0155] <Preparation of negative electrode substrate> A 5 MPa pressure vessel equipped with a stirrer was charged with 33 parts of 1,3-butadiene, 3.5 parts of itaconic acid, 63.5 parts of styrene, 0.4 parts of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of ion-exchanged water, and 0.5 parts of potassium persulfate as a polymerization initiator. After thorough stirring, the mixture was heated to 50°C to initiate polymerization. When the polymerization conversion reached 96%, the reaction was stopped by cooling, yielding a mixture containing a binder (SBR) for the negative electrode composite layer. A 5% aqueous sodium hydroxide solution was added to the mixture containing the binder for the negative electrode composite layer, adjusting the pH to 8, and then the unreacted monomer was removed by heated vacuum distillation. The mixture was then cooled to 30°C or below to obtain an aqueous dispersion containing the desired binder for the negative electrode composite layer. Next, 100 parts of artificial graphite (volume average particle diameter: 15.6 μm) as the negative electrode active material, 1 part (solids equivalent) of a 2% aqueous solution of carboxymethylcellulose sodium salt (manufactured by Nippon Paper Industries Co., Ltd., product name "MAC350HC") as a viscosity modifier, and ion-exchanged water were mixed to adjust the solids concentration to 68%, and then further mixed at 25°C for 60 minutes. The solids concentration was further adjusted to 62% with ion-exchanged water, and then further mixed at 25°C for 15 minutes. To the resulting mixture, 1.5 parts (solids equivalent) of the aqueous dispersion containing the binder for the negative electrode composite layer and ion-exchanged water were added, and the final solids concentration was adjusted to 52%, and then further mixed for 10 minutes. This mixture was degassed under reduced pressure to obtain a nonaqueous secondary battery negative electrode slurry composition with good fluidity. The obtained nonaqueous secondary battery negative electrode slurry composition was applied to both sides of a 20 μm thick copper foil current collector using a comma coater so that the dried film thickness was approximately 150 μm, and then dried. This drying was performed by conveying the copper foil at a speed of 0.5 m / min through an oven at a temperature of 60 ° C for 2 minutes. Thereafter, a heat treatment was performed at a temperature of 120 ° C for 2 minutes to obtain a pre-pressed negative electrode blank. This pre-pressed negative electrode blank was rolled using a roll press to obtain a pre-pressed negative electrode blank with a negative electrode composite layer thickness of 80 μm.

[0156] <Preparation of positive electrode substrate> 100 parts of LiCoO2 with a volume average particle size of 12 μm as the positive electrode active material, 2 parts of acetylene black (manufactured by Denka Co., Ltd., product name "HS-100") as the conductive material, 2 parts of polyvinylidene fluoride (manufactured by Kureha Corporation, product name "#7208") as the binder in solids equivalent, and N-methylpyrrolidone as the solvent were mixed to a total solids concentration of 70%. These were mixed using a planetary mixer to obtain a slurry composition for a nonaqueous secondary battery positive electrode. The obtained nonaqueous secondary battery positive electrode slurry composition was applied to both sides of a 20 μm thick aluminum foil current collector using a comma coater so that the dried film thickness was approximately 150 μm, and then dried. This drying was performed by conveying the aluminum foil at a speed of 0.5 m / min in an oven at a temperature of 60 ° C for 2 minutes. Then, the aluminum foil was heated at a temperature of 120 ° C for 2 minutes to obtain a positive electrode blank. The obtained positive electrode blank was then rolled using a roll press to obtain a pressed positive electrode blank having a positive electrode mixture layer.

[0157] <Preparing the separator roll> A polyethylene (PE) separator substrate (product name "ND412" manufactured by Asahi Kasei) was prepared.

[0158] <Manufacturing of laminate> Using the adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, and separator raw sheet thus prepared, a laminate was prepared as shown in Fig. 3. In Fig. 3, reference numeral 91 denotes a conveying roller, and reference numeral 92 denotes a heat roller. Specifically, while negative electrode raw 20A unwound from a negative electrode raw roll was transported at a speed of 10 m / min, an adhesive layer composition was supplied from the inkjet head of an inkjet coating machine 52 (Konica Corporation, KM1024 (shear mode type)) onto one surface of negative electrode raw 20A, and a second separator raw 30A unwound from a separator raw roll and negative electrode raw 20A were bonded together with pressure rollers 61, 62. Furthermore, an adhesive layer composition was supplied from the inkjet head of an inkjet coating machine 51 (Konica Corporation, KM1024 (shear mode type)) onto the other surface of negative electrode raw 20A, and a laminate of first separator raw 10A unwound from a separator raw roll and negative electrode raw 20A and second separator raw 30A were bonded together with pressure rollers 61, 62. Furthermore, an adhesive layer composition was supplied from the inkjet head of an inkjet coater 53 (Konica Corporation, KM1024 (shear mode type)) to the surface of the first separator raw sheet 10A opposite the negative electrode raw sheet 20A side, and a pre-cut positive electrode 40 was placed on it. The laminate of the first separator raw sheet 10A, the negative electrode raw sheet 20A, and the second separator raw sheet 30A was then bonded to the positive electrode 40 with pressure rollers 61 and 62. Then, an adhesive layer composition was supplied from the inkjet head of an inkjet coater 54 (Konica Corporation, KM1024 (shear mode type)) onto the positive electrode 40, and the laminate was then cut with a cutter 70 to obtain a laminate in which the second separator, negative electrode, first separator, and positive electrode were stacked in this order. Here, at the end of each current collector of the positive electrode 40 and the negative electrode raw sheet 20A, a portion where no electrode composite layer (positive electrode composite layer or negative electrode composite layer) is formed is provided, and the portion is punched out in advance to form a tab of a desired size, and the stacking is performed so that the positive electrode tab and the negative electrode tab are arranged on the same edge side of the bonding surfaces X and Y between the electrode and the separator. The bonding using the pressure rollers 61 and 62 was carried out at a temperature of 25° C. and a pressure of 2 MPa. Furthermore, the supplied adhesive layer composition was dried by using a heat roller 92 as part of the conveying roller 91 (drying temperature: 70° C., drying time: 1 second).

[0159] The adhesive layer composition was supplied from the coaters 51 to 54 so that the adhesive layer composition was in a uniform dot pattern. The dot size was 100 μm in diameter, and the intervals between dots were 400 μm. The basis weight of the adhesive material was 0.2 g / m 2 The coverage rate was measured and found to be 6.5%.

[0160] <Secondary battery manufacturing> Five stacks of the above-prepared laminates were stacked and pressed at 25°C and 2 MPa for 10 seconds to produce a stack. This stack was then wrapped in an aluminum packaging exterior and filled with an electrolyte (solvent: ethylene carbonate / diethyl carbonate / vinylene carbonate = 68.5 / 30 / 1.5 (volume ratio); electrolyte: 1M LiPF6). The opening of the aluminum packaging exterior was then heat-sealed at 150°C to produce a stacked lithium-ion secondary battery with a capacity of 800 mAh. The lithium deposition rate on the negative electrode surface of the resulting secondary battery, its output characteristics, and the increase in resistance during cycle testing were evaluated. The results are shown in Table 2.

[0161] Example 2 In preparing the adhesive layer composition of Example 1, the aqueous dispersion of particulate polymer 2 obtained in Production Example 2 was used instead of the aqueous dispersion of particulate polymer 1 obtained in Production Example 1. In the same manner as in Example 1, the adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, separator raw sheet, laminate, and secondary battery were produced and prepared. Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0162] Example 3 In preparing the adhesive layer composition of Example 1, the aqueous dispersion of particulate polymer 3 obtained in Production Example 3 was used instead of the aqueous dispersion of particulate polymer 1 obtained in Production Example 1. In the same manner as in Example 1, the adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, separator raw sheet, laminate, and secondary battery were produced and prepared. Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0163] Example 4 In preparing the adhesive layer composition of Example 1, the aqueous dispersion of particulate polymer 4 obtained in Production Example 4 was used instead of the aqueous dispersion of particulate polymer 1 obtained in Production Example 1. In the same manner as in Example 1, the adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, separator raw sheet, laminate, and secondary battery were produced and prepared. Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0164] Example 5 In preparing the adhesive layer composition of Example 1, the aqueous dispersion of particulate polymer 5 obtained in Production Example 5 was used instead of the aqueous dispersion of particulate polymer 1 obtained in Production Example 1. In the same manner as in Example 1, the adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, separator raw sheet, laminate, and secondary battery were produced and prepared. Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0165] Example 6 In preparing the adhesive layer composition of Example 1, the aqueous dispersion of particulate polymer 6 obtained in Production Example 6 was used instead of the aqueous dispersion of particulate polymer 1 obtained in Production Example 1. In the same manner as in Example 1, the adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, separator raw sheet, laminate, and secondary battery were produced and prepared. Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0166] Example 7 In preparing the adhesive layer composition of Example 1, the aqueous dispersion of particulate polymer 7 obtained in Production Example 7 was used instead of the aqueous dispersion of particulate polymer 1 obtained in Production Example 1. In the same manner as in Example 1, the adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, separator raw sheet, laminate, and secondary battery were produced and prepared. Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0167] Example 8 In preparing the adhesive layer composition of Example 1, the aqueous dispersion of particulate polymer 8 obtained in Production Example 8 was used instead of the aqueous dispersion of particulate polymer 1 obtained in Production Example 1. In the same manner as in Example 1, the adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, separator raw sheet, laminate, and secondary battery were produced and prepared. Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0168] Example 9 The adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, separator raw sheet, laminate, and secondary battery were produced and prepared in the same manner as in Example 1, except that a polypropylene (PP) separator raw sheet (product name: Celgard #2500) was used instead of a polyethylene (PE) separator raw sheet (product name: "ND412" manufactured by Asahi Kasei). Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0169] Example 10 In preparing the adhesive layer composition of Example 1, the aqueous dispersion of particulate polymer 10 obtained in Production Example 10 was used instead of the aqueous dispersion of particulate polymer 9 obtained in Production Example 9. In the same manner as in Example 1, the adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, separator raw sheet, laminate, and secondary battery were produced and prepared. Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0170] (Comparative Example 1) In preparing the adhesive layer composition of Example 1, the aqueous dispersion of particulate polymer 11 obtained in Comparative Production Example 1 was used instead of the aqueous dispersion of particulate polymer 1 obtained in Production Example 1. In the same manner as in Example 1, the adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, separator raw sheet, laminate, and secondary battery were produced and prepared. Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0171] (Comparative Example 2) In preparing the adhesive layer composition of Example 1, the aqueous dispersion of particulate polymer 12 obtained in Comparative Production Example 2 was used instead of the aqueous dispersion of particulate polymer 1 obtained in Production Example 1. The adhesive layer composition, negative electrode blank, positive electrode blank, and separator blank were produced and prepared in the same manner as in Example 1. Then, various measurements and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2. When the inkjet discharge characteristics of the adhesive layer composition were evaluated in the same manner as in Example 1, the adhesive layer composition could not be discharged. Therefore, a laminate and a secondary battery could not be produced.

[0172] In Tables 1 and 2 below, "MMA" indicates methyl methacrylate, "BA" indicates butyl acrylate, "2EHA" indicates 2-ethylhexyl acrylate, "AN" indicates acrylonitrile, "St" indicates styrene, "MAA" indicates methacrylic acid, "AA" indicates acrylic acid, "Aam" indicates acrylamide, "AGE" indicates allyl glycidyl ether, "AMA" indicates allyl methacrylate; "EDMA" refers to ethylene glycol dimethacrylate; "M90G" refers to "NK Ester M90G" (methoxypolyethylene glycol methacrylate (repeating number of ethylene oxide groups n≒9)) manufactured by Shin-Nakamura Chemical Co., Ltd. "AM90G" refers to "NK Ester AM90G" (methoxypolyethylene glycol acrylate (repeating number of ethylene oxide groups n≒9)) manufactured by Shin-Nakamura Chemical Co., Ltd. "PE" indicates polyethylene; "PP" refers to polypropylene. [Table 1] [Table 2]

[0173] As can be seen from the results shown in Table 2, in Examples 1 to 10, which used non-aqueous secondary battery adhesive layer compositions containing a particulate polymer having a core-shell structure in which the polymer constituting the shell portion contains an alkylene oxide group-containing monomer unit, it was possible to simultaneously achieve high levels of ink jet discharge characteristics, adhesive strength, and battery characteristics (output characteristics, resistance increase in cycle tests).In contrast, in Comparative Example 1, which used a non-aqueous secondary battery adhesive layer composition containing a particulate polymer having a core-shell structure in which the polymer constituting the shell portion does not contain an alkylene oxide group-containing monomer unit, and Comparative Example 2, which used a non-aqueous secondary battery adhesive layer composition containing a particulate polymer without a core-shell structure, it was found that it was not possible to simultaneously achieve high levels of ink jet discharge characteristics, adhesive strength, and battery characteristics (output characteristics, resistance increase in cycle tests). The reason for the slight deterioration in adhesive strength in Example 5 is presumably due to the high mass content of the shell portion, which has a high glass transition temperature. The reason why the battery characteristics in Examples 6 and 7 were slightly worsened is presumably due to the high degree of swelling. The reason why the adhesive strength in Example 9 is slightly worse is presumably because the polypropylene separator is more hydrophobic than the polyethylene separator. [Industrial Applicability]

[0174] According to the present invention, it is possible to provide a non-aqueous secondary battery adhesive layer that can firmly bond battery components together under pressure at room temperature while ensuring inkjet ejection characteristics, and it is also possible to provide a non-aqueous secondary battery adhesive layer composition that can enable a non-aqueous secondary battery to exhibit excellent battery characteristics. Furthermore, the present invention can provide an adhesive layer for a non-aqueous secondary battery that can firmly bond battery components together under pressure at room temperature and enable the non-aqueous secondary battery to exhibit excellent electrical properties. Furthermore, according to the present invention, it is possible to provide a laminate for a non-aqueous secondary battery that can enable the non-aqueous secondary battery to exhibit excellent electrical properties. Furthermore, the present invention can provide a non-aqueous secondary battery with excellent electrical characteristics. Furthermore, the present invention can provide a method for producing an adhesive layer for a non-aqueous secondary battery that can firmly bond battery components together under pressure at room temperature and enable the non-aqueous secondary battery to exhibit excellent electrical properties. Furthermore, the present invention can provide a method for producing a laminate for a non-aqueous secondary battery that can provide excellent electrical properties to the non-aqueous secondary battery. [Explanation of symbols]

[0175] 10A First separator roll 20A negative electrode material 30A Second separator roll 40 positive electrode 50 droplets 51~54 Coating machine (nozzle head) 61,62 Pressure roller 70 cutting machine 91 Conveyor roller 92 Heat Roller 300 Particulate polymer 310 Core 310S Core outer surface 320 Shell part

Claims

1. A non-aqueous secondary battery adhesive layer composition that is applied by an inkjet method, the composition comprising: the particulate polymer has a core-shell structure including a core portion and a shell portion covering the outer surface of the core portion, The shell portion is made of a polymer containing an alkylene oxide group-containing monomer unit.

2. 2 . The composition for a non-aqueous secondary battery adhesive layer according to claim 1 , wherein the polymer constituting the shell portion contains the alkylene oxide group-containing monomer unit in an amount of 3% by mass to 60% by mass.

3. 2. The non-aqueous secondary battery adhesive layer composition according to claim 1, wherein the polymer constituting the shell portion contains 35% by mass or more and 96% by mass or less of aromatic vinyl monomer units.

4. The composition for a non-aqueous secondary battery adhesive layer according to claim 1 , wherein the core portion is made of a polymer containing 50% by mass or more and 98% by mass or less of (meth)acrylic acid ester monomer units.

5. 2. The nonaqueous secondary battery adhesive layer composition according to claim 1, wherein the polymer constituting the core portion has a glass transition temperature of −50° C. or higher and 25° C. or lower, and the polymer constituting the shell portion has a glass transition temperature of 50° C. or higher and 200° C. or lower.

6. 6. The non-aqueous secondary battery adhesive layer composition according to claim 5, wherein the polymer constituting the core portion has a glass transition temperature of −40° C. or higher and 25° C. or lower.

7. 2. The non-aqueous secondary battery adhesive layer composition according to claim 1, wherein the particulate polymer has a volume average particle size of 100 nm or more and 1500 nm or less.

8. An adhesive layer for a non-aqueous secondary battery, which is formed using the composition for a non-aqueous secondary battery adhesive layer according to any one of claims 1 to 7.

9. A step of applying the non-aqueous secondary battery adhesive layer composition according to any one of claims 1 to 7 onto a substrate by an inkjet method; and drying the composition for a non-aqueous secondary battery adhesive layer applied to the substrate.

10. A laminate for a non-aqueous secondary battery comprising an electrode and a separator, A laminate for a non-aqueous secondary battery, wherein the electrode and the separator are bonded via the adhesive layer for a non-aqueous secondary battery according to claim 8 .

11. supplying an adhesive material to at least one bonding surface of the electrode and the separator; and a step of applying pressure to the electrode and the separator at room temperature via the bonding surfaces to which the adhesive material has been applied, 8. A method for producing a laminate for a non-aqueous secondary battery, wherein the adhesive material is the composition for a non-aqueous secondary battery adhesive layer according to claim 1.

12. A non-aqueous secondary battery comprising the laminate for a non-aqueous secondary battery according to claim 10.

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