Composition for nonaqueous secondary battery adhesive layer, nonaqueous secondary battery adhesive layer and method for producing same, laminate for nonaqueous secondary battery and method for producing same, and nonaqueous secondary battery

Abstract

The purpose of the present invention is to provide a composition that is for a nonaqueous secondary battery adhesive layer and that is capable of firmly adhering, even through room-temperature pressure-application, battery members to each other. This composition for a nonaqueous secondary battery adhesive layer comprises a first particulate polymer and a second particulate polymer different from the first particulate polymer. The first particulate polymer has a core-shell structure provided with a core part and a shell part which covers at least a portion of the outer surface of the core part. The polymer of the core part and the second particulate polymer each include a (meth)acrylate monomer unit having a chain-like alkyl group which has at least 4 carbon atoms. When A mass% represents the proportion of the (meth)acrylate monomer unit having a chain-like alkyl group which has at least 4 carbon atoms in the first particulate polymer, B mass% represents the proportion of the (meth)acrylate monomer unit having a chain-like alkyl group which has at least 4 carbon atoms in the second particulate polymer, X mass% represents the contained proportion of the first particulate polymer with respect to the total mass of the first particulate polymer and the second particulate polymer, and Y mass% represents the contained proportion of the second particulate polymer with respect to the total mass of the first particulate polymer and the second particulate polymer, the value calculated by formula (1): (AX+BY) / (X+Y) is 75 mass% or more.

Description

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

[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.

[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 are capable of repeated charging and discharging, 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, 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 are used as battery components. 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 onto a substrate such as an electrode substrate or separator substrate, and drying it.

[0004] In recent years, attempts have been made to improve adhesive layer compositions and methods for forming adhesive layers (adhesive materials) using such adhesive layer compositions, with the aim of firmly bonding battery components together while allowing secondary batteries to exhibit excellent battery characteristics and improving the manufacturing efficiency of secondary batteries. For example, Patent Document 1 describes an adhesive layer composition that contains organic particles having a core-shell structure, a thixotropic agent, and water and that satisfies specified properties. According to Patent Document 1, by ejecting the adhesive layer composition as fine droplets using an inkjet method, an adhesive layer can be favorably formed, and a substrate and an adherend can be firmly bonded via the adhesive layer.

[0005] International Publication No. 2020 / 045246

[0006] However, when battery components are pressure-bonded together via an adhesive layer formed from the adhesive layer composition to produce a laminate, there is a need for the adhesive layer composition of the above-mentioned prior art to provide better adhesion between the battery components even when the pressure-bonding is performed at room temperature under pressure. In other words, there is room for further improvement in the adhesive layer composition of the above-mentioned prior art in terms of increasing the adhesiveness of the adhesive layer formed from the adhesive layer composition under room temperature under pressure.

[0007] Therefore, an object of the present invention is to provide a composition for a non-aqueous secondary battery adhesive layer that can form a non-aqueous secondary battery adhesive layer that firmly bonds battery components together even when pressurized at room temperature. Another object of the present invention is to provide a non-aqueous secondary battery adhesive layer that can firmly bond battery components together even when pressurized at room temperature, and a method for manufacturing the same. Another object of the present invention is to provide a non-aqueous secondary battery laminate that exhibits excellent adhesion between battery components, and a method for manufacturing the same. Another object of the present invention is to provide a non-aqueous secondary battery that exhibits excellent adhesion between battery components.

[0008] The present inventors have conducted extensive research to solve the above-mentioned problems, and have found that the above-mentioned problems can be solved by a non-aqueous secondary battery adhesive layer composition that includes a first particulate polymer and a second particulate polymer different from the first particulate polymer, the composition containing predetermined monomer units in a desired ratio, and have completed the present invention.

[0009] That is, the present invention has an object to solve the above-mentioned problems, and the non-aqueous secondary battery adhesive layer composition of the present invention is a non-aqueous secondary battery adhesive layer composition comprising a first particulate polymer and a second particulate polymer different from the first particulate polymer, wherein the first particulate polymer has a core-shell structure comprising a core portion and a shell portion covering at least a part of the outer surface of the core portion, and both the core portion polymer and the second particulate polymer comprise (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms, When the proportion of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the first particulate polymer is A% by mass, the proportion of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the second particulate polymer is B% by mass, the content of the first particulate polymer in the total mass of the first particulate polymer and the second particulate polymer is X% by mass, and the content of the second particulate polymer in the total mass of the first particulate polymer and the second particulate polymer is Y% by mass, the value calculated by the following formula (1): (AX + BY) / (X + Y) ... (1) is 75% by mass or more. The above-mentioned composition for a nonaqueous secondary battery adhesive layer can form a nonaqueous secondary battery adhesive layer that firmly bonds battery components together even when pressurized at room temperature. In this specification, the term "second particulate polymer different from the first particulate polymer" means that at least one of the composition and particle structure is different, preferably at least the particle structure is different. As used herein, the term "monomer unit" of a polymer refers to a "repeating unit that can be derived from a monomer and is contained in a polymer obtained using that monomer." As used herein, "(meth)acrylate" refers to an acrylate and / or methacrylate. As used herein, "a (meth)acrylate having a chain alkyl group having 4 or more carbon atoms" refers to a (meth)acrylate in which a chain alkyl group having 4 or more carbon atoms is bonded to a non-carbonyl oxygen atom. As used herein, "room temperature" refers to a temperature in the range of 0°C or higher and 35°C or lower.

[0010] In the composition for a non-aqueous secondary battery adhesive layer of the present invention, it is preferable that the glass transition temperature of the core polymer is −20° C. or lower, and the glass transition temperature of the second particulate polymer is −15° C. or lower. When the glass transition temperatures of the core polymer and the second particulate polymer are each below the above-mentioned upper limit, a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed even when pressurized at room temperature. In this specification, the “glass transition temperature” can be measured using the measurement method described in the Examples of this specification.

[0011] In the non-aqueous secondary battery adhesive layer composition of the present invention, the glass transition temperature of the polymer of the shell portion is preferably 50° C. or higher. When the glass transition temperature of the polymer of the shell portion is equal to or higher than the lower limit, clogging of the nozzle when the non-aqueous secondary battery adhesive layer composition is ejected as fine droplets by an inkjet method can be suppressed. In other words, the inkjet ejection characteristics can be improved.

[0012] In the non-aqueous secondary battery adhesive layer composition of the present invention, the mass proportion of the shell portion in the first particulate polymer is preferably 2% by mass or more and 15% by mass or less. When the mass proportion of the shell portion is equal to or greater than the lower limit, the inkjet discharge characteristics of the non-aqueous secondary battery adhesive layer composition can be improved. On the other hand, when the mass proportion of the shell portion is equal to or less than the upper limit, a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed even when pressurized at room temperature. The mass proportion of the shell portion in the first particulate polymer is determined from the ratio of the thickness of the core portion to the shell portion and the specific gravity of the particulate polymer.

[0013] In the non-aqueous secondary battery adhesive layer composition of the present invention, the proportion of the (meth)acrylate monomer units having a chain alkyl group of 4 or more carbon atoms in the core polymer is preferably 90% by mass or more, when the total monomer units contained in the core polymer is 100% by mass, and the proportion of the (meth)acrylate monomer units having a chain alkyl group of 4 or more carbon atoms in the second particulate polymer is preferably 75% by mass or more, when the total monomer units contained in the second particulate polymer is 100% by mass. When the proportions of the (meth)acrylate monomer units having a chain alkyl group of 4 or more carbon atoms in the core polymer and the second particulate polymer are each equal to or greater than the above-mentioned lower limits, a non-aqueous secondary battery adhesive layer can be formed that more firmly bonds battery components together even when pressurized at room temperature. In this specification, the proportions of various monomer units in the polymer are １ H-NMR and １３ It can be measured using a nuclear magnetic resonance (NMR) method such as C-NMR.

[0014] In the non-aqueous secondary battery adhesive layer composition of the present invention, the structural formula of the (meth)acrylate monomer unit having a chain alkyl group of 4 or more carbon atoms of the second particulate polymer is preferably the same as the structural formula of the (meth)acrylate monomer unit having a chain alkyl group of 4 or more carbon atoms of the first particulate polymer. If the structural formula of the (meth)acrylate monomer unit having a chain alkyl group of 4 or more carbon atoms of the second particulate polymer is the same as the structural formula of the (meth)acrylate monomer unit having a chain alkyl group of 4 or more carbon atoms of the first particulate polymer, a non-aqueous secondary battery adhesive layer can be formed that more firmly bonds battery components together even when pressurized at room temperature.

[0015] In the non-aqueous secondary battery adhesive layer composition of the present invention, the (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms of the first particulate polymer and the second particulate polymer are preferably both (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms and 10 or less carbon atoms. If the (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms of the first particulate polymer and the second particulate polymer are both (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms and 10 or less carbon atoms, a non-aqueous secondary battery adhesive layer can be formed that more firmly bonds battery components together even when pressurized at room temperature.

[0016] In the non-aqueous secondary battery adhesive layer composition of the present invention, the (meth)acrylate monomer units having a chain alkyl group with 4 or more carbon atoms in the first particulate polymer and the second particulate polymer are preferably both n-butyl acrylate units. When the (meth)acrylate monomer units having a chain alkyl group with 4 or more carbon atoms in the first particulate polymer and the second particulate polymer are both n-butyl acrylate units, a non-aqueous secondary battery adhesive layer can be formed that further firmly bonds battery components together even when pressurized at room temperature.

[0017] In the non-aqueous secondary battery adhesive layer composition of the present invention, at least one of the first particulate polymer and the second particulate polymer preferably further contains a nitrile group-containing monomer unit. When at least one of the first particulate polymer and the second particulate polymer further contains a nitrile group-containing monomer unit, the inkjet ejection characteristics of the non-aqueous secondary battery adhesive layer composition can be improved. Furthermore, when at least one of the first particulate polymer and the second particulate polymer further contains a nitrile group-containing monomer unit, a non-aqueous secondary battery with excellent cycle characteristics can be obtained.

[0018] The present invention also aims to solve the above-mentioned problems, and provides a non-aqueous secondary battery adhesive layer according to the present invention, which is formed using the above-mentioned non-aqueous secondary battery adhesive layer composition. Such a non-aqueous secondary battery adhesive layer can firmly bond battery components together even when pressure is applied at room temperature.

[0019] The present invention also aims to solve the above-mentioned problems, and provides a method for producing a non-aqueous secondary battery adhesive layer, comprising the steps of applying the above-mentioned non-aqueous secondary battery adhesive layer composition to a substrate and drying the non-aqueous secondary battery adhesive layer composition applied to the substrate. This method for producing a non-aqueous secondary battery adhesive layer can produce a non-aqueous secondary battery adhesive layer that can firmly bond battery components together even when pressurized at room temperature.

[0020] The present invention also aims to solve the above-mentioned problems, and provides a laminate for a nonaqueous secondary battery comprising an electrode and a separator, the electrode and the separator being bonded via the adhesive layer for a nonaqueous secondary battery. Such a laminate for a nonaqueous secondary battery has excellent adhesion between battery components.

[0021] The present invention also aims to solve the above-mentioned problems, and provides a method for producing a laminate for a nonaqueous secondary battery, the method comprising the steps of: supplying an adhesive material to at least one bonding surface of an electrode and a separator; and bonding the electrode and the separator together by applying pressure via the bonding surface to which the adhesive material has been supplied, wherein the adhesive material is made from the above-mentioned nonaqueous secondary battery adhesive layer composition. Such a method for producing a laminate for a nonaqueous secondary battery can produce a laminate for a nonaqueous secondary battery having excellent adhesion between battery components.

[0022] Another object of the present invention is to solve the above-mentioned problems, and the non-aqueous secondary battery of the present invention includes the above-mentioned laminate for a non-aqueous secondary battery. Such a non-aqueous secondary battery has excellent adhesion between battery components.

[0023] According to the present invention, a composition for a non-aqueous secondary battery adhesive layer can be provided, which can form a non-aqueous secondary battery adhesive layer that firmly bonds battery components together even when pressurized at room temperature. Furthermore, according to the present invention, a non-aqueous secondary battery adhesive layer and a method for manufacturing the same can be provided, which can firmly bond battery components together even when pressurized at room temperature. Furthermore, according to the present invention, a non-aqueous secondary battery laminate and a method for manufacturing the same can be provided, which exhibit excellent adhesion between battery components. Furthermore, according to the present invention, a non-aqueous secondary battery exhibiting excellent adhesion between battery components can be provided.

[0024] 1 is a cross-sectional view schematically illustrating the structure of an example of a first particulate polymer. 2 is a diagram illustrating an example of a manufacturing process for a laminate for a non-aqueous secondary battery of the present invention. 3 is a diagram illustrating a manufacturing process for a laminate for a non-aqueous secondary battery in Examples and Comparative Examples.

[0025] Hereinafter, embodiments of the present invention will be described in detail. Here, the composition for a non-aqueous secondary battery adhesive layer of the present invention can be used when forming the adhesive layer for a non-aqueous secondary battery of the present invention. The adhesive layer for a non-aqueous secondary battery of the present invention can be produced, for example, by the method for producing an adhesive layer for a non-aqueous secondary battery of the present invention. The adhesive layer for a non-aqueous secondary battery of the present invention can be used when producing the laminate for a non-aqueous secondary battery of the present invention and the non-aqueous secondary battery of the present invention. The laminate for a non-aqueous secondary battery 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 method for producing a laminate for a non-aqueous secondary battery of the present invention. And the non-aqueous secondary battery of the present invention includes the laminate for a non-aqueous secondary battery of the present invention.

[0026] (Non-aqueous secondary battery adhesive layer composition) The non-aqueous secondary battery adhesive layer composition of the present invention comprises a first particulate polymer and a second particulate polymer different from the first particulate polymer. The non-aqueous secondary battery adhesive layer composition of the present invention is usually a slurry composition in which a particulate polymer is dispersed in a solvent such as water, and may optionally contain other components in addition to the first particulate polymer and the second particulate polymer.

[0027] In the non-aqueous secondary battery adhesive layer composition of the present invention, both the core polymer of the first particulate polymer and the second particulate polymer contain (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms, and when the proportion of the (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the first particulate polymer is A mass%, the proportion of the (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the second particulate polymer is B mass%, the content of the first particulate polymer in the total mass of the first particulate polymer and the second particulate polymer is X mass%, and the content of the second particulate polymer in the total mass of the first particulate polymer and the second particulate polymer is Y mass%, the value calculated by the following formula (1): (AX + BY) / (X + Y) (1) is 75 mass% or more. Then, by using the above-mentioned non-aqueous secondary battery adhesive layer composition of the present invention, a non-aqueous secondary battery adhesive layer that firmly bonds battery components together can be formed even when pressurized at room temperature. The reason why an adhesive layer formed from the adhesive layer composition of the present invention exhibits good adhesion even when pressurized at room temperature is unclear, but is presumed to be as follows. Specifically, if the first particulate polymer and the second particulate polymer contain (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms, the nonaqueous secondary battery adhesive layer can exhibit good adhesion and provide strong adhesive strength. Furthermore, if the value calculated by Equation (1) is 75% by mass or more, the compatibility between polymers in the nonaqueous secondary battery adhesive layer is improved, resulting in the formation of a nonaqueous secondary battery adhesive layer that firmly bonds battery components together even when pressurized at room temperature. The value calculated by Equation (1) is preferably 80% by mass or more, and more preferably 90% by mass or more, because this allows the formation of a nonaqueous secondary battery adhesive layer that more firmly bonds battery components together even when pressurized at room temperature. On the other hand, the value calculated by Equation (1) is preferably 99% by mass or less, because this allows the formation of an nonaqueous secondary battery adhesive layer that more firmly bonds battery components together even when pressurized at room temperature.

[0028] <First Particulate Polymer> The first particulate polymer has a core-shell structure comprising a core portion and a shell portion covering at least a part of the outer surface of the core portion. Here, the shell portion may cover the entire outer surface of the core portion, or may cover only a part 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 from the outside, as long as holes communicating the inside and outside of the shell portion are formed, the shell portion is a shell portion that partially covers the outer surface of the core portion.

[0029] The cross-sectional structure of an example of the first particulate polymer is shown in Figure 1. In Figure 1, the first particulate polymer 300 has a core-shell structure comprising a core portion 310 and a shell portion 320. Here, the core portion 310 is a portion of the first particulate polymer 300 that is located more inward than the shell portion 320. The shell portion 320 is a portion that covers the outer surface 310S of the core portion 310, and is usually the outermost portion of the first particulate polymer 300. In the example of Figure 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 first particulate polymer may have any constituent element other than the core and shell portions described above, as long as the intended effect is not significantly impaired. Specifically, for example, the first particulate polymer may have a portion formed of a polymer different from the core portion inside the core portion. As a specific example, the seed particles used when producing the first particulate polymer by seed polymerization may remain inside the core portion. However, from the viewpoint of significantly exhibiting the intended effect, it is preferable that the first particulate polymer has only the core portion and the shell portion.

[0031] As described below, the first particulate polymer has a core portion containing a (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms, and therefore the first particulate polymer also contains a (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms. The (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms is a repeating unit that can be derived from a (meth)acrylate monomer having a chain alkyl group having 4 or more carbon atoms. Examples of the (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms include butyl acrylate units such as n-butyl acrylate unit and t-butyl acrylate unit; hexyl acrylate units such as n-hexyl acrylate unit; octyl acrylate units such as n-octyl acrylate unit and 2-ethylhexyl acrylate unit; decyl acrylate units such as n-decyl acrylate unit; dodecyl acrylate units such as n-dodecyl acrylate unit; butyl methacrylate units such as n-butyl methacrylate unit and t-butyl methacrylate unit; hexyl methacrylate units such as n-hexyl methacrylate unit; octyl methacrylate units such as n-octyl methacrylate unit and 2-ethylhexyl methacrylate unit; decyl methacrylate units such as n-decyl methacrylate unit; and dodecyl methacrylate units such as n-dodecyl methacrylate unit. The first particulate polymer may contain one of these alone or two or more of them in any ratio.

[0032] The (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the first particulate polymer is preferably a (meth)acrylate monomer unit having a chain alkyl group having 4 to 10 carbon atoms, and more preferably a (meth)acrylate monomer unit having a chain alkyl group having 4 to 8 carbon atoms. When the number of carbon atoms in the chain alkyl group is equal to or greater than the lower limit, a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together even when pressurized at room temperature can be formed. On the other hand, when the number of carbon atoms in the chain alkyl group is equal to or less than the upper limit, the crystallinity of the polymer decreases, lowering the glass transition temperature, and as a result, improving the adhesive strength between battery components when pressurized at room temperature. The (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the first particulate polymer is particularly preferably an n-butyl acrylate unit, since it can form a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together even when pressurized at room temperature.

[0033] The proportion of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the first particulate polymer is preferably 75% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, particularly preferably 90% by mass or more, and preferably 99% by mass or less, and more preferably 97% by mass or less, when the total repeating units (total monomer units) contained in the first particulate polymer is taken as 100% by mass. When the proportion is equal to or greater than the lower limit, a nonaqueous secondary battery adhesive layer can be formed that more firmly bonds battery components together even under pressure at room temperature. Furthermore, when the proportion is equal to or greater than the lower limit, a secondary battery with excellent cycle characteristics can be obtained. On the other hand, when the proportion is equal to or less than the upper limit, inkjet ejection characteristics can be improved.

[0034] The first particulate polymer preferably further contains a nitrile group-containing monomer unit. The nitrile group-containing monomer unit is a repeating unit that can be derived from a nitrile group-containing monomer. When the first particulate polymer further contains a nitrile group-containing monomer unit, the inkjet ejection characteristics of the non-aqueous secondary battery adhesive layer composition can be improved. Furthermore, when the first particulate polymer further contains a nitrile group-containing monomer unit, a non-aqueous secondary battery with excellent cycle characteristics can be obtained. Examples of the nitrile group-containing monomer unit include α,β-ethylenically unsaturated nitrile monomer units such as acrylonitrile units; α-halogenoacrylonitrile units such as α-chloroacrylonitrile units and α-bromoacrylonitrile units; and α-alkylacrylonitrile units such as methacrylonitrile units and α-ethylacrylonitrile units. The first particulate polymer may contain one of these units alone or two or more units in any ratio. The nitrile group-containing monomer unit is preferably an acrylonitrile unit.

[0035] The proportion of the nitrile group-containing monomer units in the first particulate polymer is preferably 1% by mass or more, preferably 15% by mass or less, and more preferably 5% by mass or less, when the total repeating units (total monomer units) contained in the first particulate polymer is taken as 100% by mass. When the proportion of the nitrile group-containing monomer units in the first particulate polymer is equal to or greater than the above-mentioned lower limit, the inkjet ejection characteristics of the non-aqueous secondary battery adhesive layer composition can be further improved. Furthermore, when the proportion of the nitrile group-containing monomer units in the first particulate polymer is equal to or greater than the above-mentioned lower limit, a non-aqueous secondary battery with superior cycle characteristics can be obtained. On the other hand, when the proportion of the nitrile group-containing monomer units in the first particulate polymer is equal to or less than the above-mentioned upper limit, a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed, even when pressurized at room temperature.

[0036] [Core Portion] The polymer of the core portion contains a (meth)acrylate monomer unit having a chain alkyl group with 4 or more carbon atoms. When the polymer of the core portion contains a (meth)acrylate monomer unit having a chain alkyl group with 4 or more carbon atoms, a non-aqueous secondary battery adhesive layer can be formed that firmly bonds battery components together even at room temperature and under pressure. Examples of (meth)acrylate monomer units having a chain alkyl group with 4 or more carbon atoms include those listed above. The polymer of the core portion may contain one of the above listed compounds alone, or two or more of them in any ratio.

[0037] The (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms in the core polymer is preferably a (meth)acrylate monomer unit having a chain alkyl group having 4 to 10 carbon atoms, and more preferably a (meth)acrylate monomer unit having a chain alkyl group having 4 to 8 carbon atoms. When the number of carbon atoms in the chain alkyl group is equal to or greater than the lower limit, a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together even when pressurized at room temperature can be formed. On the other hand, when the number of carbon atoms in the chain alkyl group is equal to or less than the upper limit, the crystallinity of the polymer decreases, lowering the glass transition temperature, and as a result, improving the adhesive strength between battery components when pressurized at room temperature. The (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms in the core polymer is particularly preferably an n-butyl acrylate unit, since it can form a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together even when pressurized at room temperature.

[0038] The proportion of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the core polymer is preferably 75% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and preferably 99% by mass or less, and more preferably 97% by mass or less, when the total repeating units (total monomer units) contained in the core polymer is taken as 100% by mass. When the proportion is equal to or greater than the lower limit, a nonaqueous secondary battery adhesive layer can be formed that more firmly bonds battery components together even under pressure at room temperature. Furthermore, when the proportion is equal to or greater than the lower limit, a secondary battery with excellent cycle characteristics can be obtained. On the other hand, when the proportion is equal to or less than the upper limit, inkjet ejection characteristics can be improved.

[0039] It is preferable that the core polymer further contains a nitrile group-containing monomer unit. If the core polymer further contains a nitrile group-containing monomer unit, the ink jet discharge characteristics of the non-aqueous secondary battery adhesive layer composition can be improved. Furthermore, if the core polymer further contains a nitrile group-containing monomer unit, a non-aqueous secondary battery with excellent cycle characteristics can be obtained. Examples of the nitrile group-containing monomer unit include those listed above. The core polymer may contain one of the above-listed monomer units alone, or two or more of them in any ratio. It is preferable that the nitrile group-containing monomer unit is an acrylonitrile unit.

[0040] The proportion of the nitrile group-containing monomer units in the core polymer is preferably 1% by mass or more, preferably 15% by mass or less, and more preferably 5% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the core polymer. When the proportion of the nitrile group-containing monomer units in the core polymer is equal to or greater than the lower limit, the inkjet ejection characteristics of the non-aqueous secondary battery adhesive layer composition can be further improved. Furthermore, when the proportion of the nitrile group-containing monomer units in the core polymer is equal to or greater than the lower limit, a non-aqueous secondary battery with superior cycle characteristics can be obtained. On the other hand, when the proportion of the nitrile group-containing monomer units in the core polymer is equal to or less than the upper limit, a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed, even when pressurized at room temperature.

[0041] The core polymer may contain a hydrophilic group-containing monomer unit. The hydrophilic group-containing monomer unit is a repeating unit that can be derived from a hydrophilic group monomer. Examples of hydrophilic group monomers include acid group-containing monomers and hydroxyl group-containing monomers. Among these, the hydrophilic group monomer is preferably an acid group-containing monomer, since this can increase the dispersibility of the core polymer during preparation of the first particulate polymer and facilitate the formation of a shell portion on the outer surface of the core polymer. That is, the hydrophilic group-containing monomer unit is preferably an acid group-containing monomer unit.

[0042] Examples of acid group-containing monomers include monomers having an acid group, such as monomers having a carboxylic acid group, monomers having a sulfonic acid group, and monomers having a phosphate group. Examples of monomers having a carboxylic acid group include monocarboxylic acids and dicarboxylic acids. Examples of monocarboxylic acids include acrylic acid, methacrylic acid, and crotonic acid. Examples of dicarboxylic acids include maleic acid, fumaric acid, and itaconic acid. Examples of monomers 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. Examples of monomers having a phosphate group include 2-(meth)acryloyloxyethyl phosphate, methyl-2-(meth)acryloyloxyethyl phosphate, and ethyl-(meth)acryloyloxyethyl phosphate. In this specification, "(meth)allyl" means allyl and / or methallyl, "(meth)acryloyl" means acryloyl and / or methacryloyl, and "(meth)acrylic" means acrylic and / or methacrylic. Among these, as the acid group-containing monomer, a monomer having a carboxylic acid group is preferred, and among these, monocarboxylic acids are preferred, with (meth)acrylic acid being more preferred. The acid group-containing monomer may be used alone or in combination of two or more types in any ratio.

[0043] Examples of the hydroxyl group-containing monomer include monomers having a hydroxyl group, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc. One type of hydroxyl group-containing monomer may be used alone, or two or more types may be used in combination at any ratio.

[0044] The proportion of the hydrophilic group-containing monomer 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, and even more preferably 5% by mass or less, when the total repeating units (total monomer units) contained in the core polymer is taken as 100% by mass. By keeping the proportion of the hydrophilic group-containing monomer 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 the shell portion on the outer surface of the core polymer.

[0045] The core polymer preferably contains a crosslinkable monomer unit in addition to the above-mentioned monomer units. The crosslinkable monomer unit is a repeating unit that can be derived from a crosslinkable monomer. The crosslinkable monomer is a monomer that can form a crosslinked structure during or after polymerization by heating or irradiation with energy rays.

[0046] Examples of crosslinkable monomers include polyfunctional monomers having two or more polymerization reactive groups in the monomer. 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; γ-methacryloxypropyltrimethoxysilane; and (meth)acrylamides having a methylol group, such as N-methylol(meth)acrylamide. Note that (meth)acrylamides having a methylol group have a hydroxyl group, but are classified as crosslinkable monomers. 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.

[0047] The proportion of the crosslinkable monomer units in the core polymer is preferably 0.05% by mass or more, more preferably 0.08% by mass or more, and preferably 1% by mass or less, more preferably 0.3% by mass or less, and particularly preferably 0.15% by mass or less, when the total amount of all repeating units (total monomer units) contained in the core polymer is taken as 100% by mass. If the proportion of the crosslinkable monomer units is within the above range, a nonaqueous secondary battery adhesive layer can be formed that further firmly bonds battery components together even when pressurized at room temperature.

[0048] The core polymer may further contain other monomer units as desired, as long as the objectives of the present invention are not impaired. The other monomer units are repeating units that can be derived from other monomers. Examples of other monomers include vinyl chloride-based monomers such as vinyl chloride and vinylidene chloride; vinyl acetate-based monomers such as vinyl acetate; aromatic vinyl monomers such as styrene, α-methylstyrene, butoxystyrene, and vinylnaphthalene; vinylamine-based monomers such as vinylamine; vinylamide-based monomers such as N-vinylformamide and N-vinylacetamide; (meth)acrylate monomers having a chain alkyl group having 3 or less carbon atoms; and (meth)acrylamide monomers such as acrylamide and methacrylamide. These may be used alone or in combination of two or more in any ratio. In this specification, "(meth)acrylamide" refers to acrylamide and / or methacrylamide. In addition, in this specification, "a (meth)acrylate having a chain alkyl group having 3 or less carbon atoms" means a (meth)acrylate in which a chain alkyl group having 3 or less carbon atoms is bonded to a non-carbonyl oxygen atom.

[0049] [Characteristics of the Core Portion] The glass transition temperature of the polymer for the core portion is preferably −50°C or higher, more preferably −45°C or higher, and preferably −10°C or lower, more preferably −20°C or lower, and even more preferably −30°C or lower. If the glass transition temperature of the polymer for 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 for the core portion is equal to or lower than the upper limit, the polymer for the core portion can exhibit good adhesive properties, and a nonaqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed even when pressurized at room temperature. The glass transition temperature of the polymer for the core portion can be adjusted, for example, by changing the type and ratio of monomers used to prepare the polymer for the core portion.

[0050] [Shell portion] The shell portion covers at least a part of the outer surface of the core portion, and preferably has a different composition and / or properties from those of the core portion. "Different composition" means that the types and / or proportions of monomer units contained in the polymer are different. "Different properties" means that the properties, such as glass transition temperature, are different.

[0051] Examples of the monomer units contained in the polymer of the shell portion include the same monomer units as those exemplified as the monomer units contained in the polymer of the core portion. The polymer of the shell portion may contain one of the above-listed monomer units alone, or two or more of them in any ratio. Among these, it is preferable that the polymer of the shell portion contains an aromatic vinyl monomer unit. The aromatic vinyl monomer unit is a repeating unit that can be derived from an aromatic vinyl monomer. Inkjet ejection characteristics can be improved by the polymer of the shell portion containing an aromatic vinyl monomer unit. It is particularly preferable that the aromatic vinyl monomer unit is a styrene unit.

[0052] The proportion of aromatic vinyl monomer units in the shell polymer is preferably 55% by mass or more, more preferably 70% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, when the total mass of all repeating units (total monomer units) contained in the shell polymer is taken as 100% by mass. If the proportion of aromatic vinyl monomer units in the shell polymer is equal to or greater than the above lower limit, inkjet ejection characteristics can be further improved. On the other hand, the proportion of aromatic vinyl monomer units in the shell polymer is, for example, 99.9% by mass or less, alternatively, 99.6% by mass or less, 99.3% by mass or less, 99% by mass or less, or even 97% by mass or less, when the total mass of all repeating units (total monomer units) contained in the shell polymer is taken as 100% by mass.

[0053] The shell polymer may contain a hydrophilic group-containing monomer unit. Examples of hydrophilic group-containing monomers that can form the hydrophilic group-containing monomer unit of the shell polymer include the same monomers as those that can be used to form the core portion. The proportion of the hydrophilic group-containing monomer unit in the shell polymer is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, based on 100% by mass of all repeating units (total monomer units) contained in the shell polymer. If the proportion of the hydrophilic group-containing monomer unit is equal to or greater than the above lower limit, the dispersibility of the first particulate polymer is improved, and a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together even under pressure at room temperature can be formed. On the other hand, the proportion of the hydrophilic group-containing monomer unit in the shell polymer is, for example, 15% by mass or less, or may be 10% by mass or less, or may be 7% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the shell polymer.

[0054] The polymer of the shell portion may further contain, as desired, the above-mentioned (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms and the above-mentioned other monomer units, as long as the object of the present invention is not impaired.

[0055] From the viewpoint of inkjet ejection characteristics, the proportion of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the polymer for the shell portion is preferably 40% by mass or less, more preferably 15% by mass or less, even more preferably 1% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably 0% by mass (i.e., the polymer for the shell portion does not contain (meth)acrylate monomer units having a chain alkyl group having a prime number of 4 or more), when all repeating units (total monomer units) contained in the polymer for the shell portion are taken as 100% by mass. Note that "the polymer for the shell portion does not contain (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms" means that they are not detected in a measurement of the proportion of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms.

[0056] The mass proportion of the shell portion in the first particulate polymer is preferably 2% by mass or more, preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and particularly preferably 5% by mass or less. When the mass proportion 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 proportion of the shell portion is equal to or less than the upper limit, a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed even when pressurized at room temperature. Here, the mass proportion of the shell portion in the first particulate polymer is calculated from the ratio of the thickness of the core portion to the shell portion and the specific gravity of the particulate polymer, which will be described later.

[0057] [Characteristics of the Shell Portion] The glass transition temperature of the polymer of the shell portion of the first particulate polymer is preferably 35°C or higher, more preferably 50°C or higher, even more preferably 80°C or higher, and preferably 200°C or lower, more preferably 120°C or lower. If the glass transition temperature of the polymer of the shell portion is above the lower limit, the inkjet ejection characteristics can be further improved. On the other hand, if the glass transition temperature of the polymer of the shell portion is below the upper limit, the first particulate polymer becomes appropriately soft, making it possible to form a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together even when pressurized at room temperature. The glass transition temperature of the polymer of the shell portion can be adjusted, for example, by changing the type and ratio of monomers used to prepare the polymer of the shell portion.

[0058] <Characteristics of the First Particulate Polymer> The volume average particle diameter of the first particulate polymer 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 first particulate polymer is equal to or greater than the above-mentioned lower limit, 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. On the other hand, when the volume average particle diameter of the first particulate polymer is equal to or less than the above-mentioned upper limit, nozzle clogging can be further suppressed when the nonaqueous secondary battery adhesive layer composition is applied by an inkjet method, and inkjet ejection characteristics can be improved.

[0059] The ratio of the average thickness of the shell portion to the volume-average particle size of the first particulate polymer is preferably 0.1% or more, more preferably 0.5% or more, and preferably 15% or less, more preferably 10% or less. When the average thickness of the shell portion is equal to or greater than the lower limit, inkjet ejection characteristics can be improved. On the other hand, when the average thickness of the shell portion is equal to or less than the upper limit, a nonaqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed even when pressurized at room temperature.

[0060] Here, the average thickness of the shell portion of the first particulate polymer is determined by observing the cross-sectional structure of the first particulate polymer using a transmission electron microscope (TEM). Specifically, the maximum thickness of the shell portion in the cross-sectional structure of the first 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 particles of the first particulate polymer 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.

[0061] <Method for preparing first particulate polymer> The first particulate polymer can be prepared, for example, by using a monomer for a core polymer and a monomer for a shell polymer and 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 of the previous stage is successively coated with the polymer of the subsequent stage.

[0062] Therefore, an example of obtaining the first particulate polymer by multistage emulsion polymerization will be described below.

[0063] For the polymerization, an emulsifier may be used in accordance with a conventional method, for example, 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, for example, 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.

[0064] The polymerization procedure is as follows: first, a monomer for forming the core portion and an emulsifier are mixed and emulsion-polymerized all at once to obtain a particulate polymer for forming the core portion; then, a monomer for forming the shell portion is polymerized in the presence of the particulate polymer for forming the core portion to obtain a first particulate polymer.

[0065] 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.

[0066] <Second Particulate Polymer> The second particulate polymer contains (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms, and at least the particle structure is different from that of the first particulate polymer. The second particulate polymer is not particularly limited as long as it is different from the first particulate polymer in at least one of its composition and particle structure, and may, for example, have a structure that does not have a core-shell structure, such as a single-phase structure formed from a single polymer. The second particulate polymer preferably differs from the first particulate polymer in composition, such as the type of monomer unit contained in the second particulate polymer and the ratio of the monomer units. Examples of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms include those listed above. The second particulate polymer may contain one of the above-listed compounds alone, or two or more of them in any ratio.

[0067] The structural formula of the (meth)acrylate monomer unit having a chain alkyl group of 4 or more carbon atoms of the second particulate polymer is preferably the same as the structural formula of the (meth)acrylate monomer unit having a chain alkyl group of 4 or more carbon atoms of the first particulate polymer. Here, "same structural formula" means that (meth)acrylate monomer units having a chain alkyl group of 4 or more carbon atoms do not include those having different structures even if the number of oxygen atoms, carbon atoms, etc. in the (meth)acrylate monomer unit having a chain alkyl group of 4 or more carbon atoms is the same. For example, if the (meth)acrylate monomer unit having a chain alkyl group of 4 or more carbon atoms is an n-butyl acrylate unit, it cannot be said that the structural formula of the t-butyl acrylate unit is the same. If the structural formula of the (meth)acrylate monomer unit having a chain alkyl group of 4 or more carbon atoms of the second particulate polymer is the same as the structural formula of the (meth)acrylate monomer unit having a chain alkyl group of 4 or more carbon atoms of the first particulate polymer, a nonaqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed even when pressurized at room temperature.

[0068] The (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the second particulate polymer is preferably a (meth)acrylate monomer unit having a chain alkyl group having 4 to 10 carbon atoms, and more preferably a (meth)acrylate monomer unit having a chain alkyl group having 4 to 8 carbon atoms. If the number of carbon atoms in the chain alkyl group is equal to or greater than the above lower limit, a non-aqueous secondary battery adhesive layer can be formed that more firmly bonds battery components together even when pressurized at room temperature. On the other hand, if the number of carbon atoms in the chain alkyl group is equal to or less than the above upper limit, the crystallinity of the polymer decreases and the glass transition temperature drops, resulting in improved adhesive strength between battery components when pressurized at room temperature. Here, when the (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the second particulate polymer is a (meth)acrylate monomer unit having a chain alkyl group having 4 to 10 carbon atoms, it is preferable that the (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the first particulate polymer is also a (meth)acrylate monomer unit having a chain alkyl group having 4 to 10 carbon atoms, and when the (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the second particulate polymer is a (meth)acrylate monomer unit having a chain alkyl group having 4 to 8 carbon atoms, it is more preferable that the (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the first particulate polymer is also a (meth)acrylate monomer unit having a chain alkyl group having 4 to 8 carbon atoms. That is, the (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms of the second particulate polymer and the first particulate polymer are preferably both (meth)acrylate monomer units having a chain alkyl group having 4 to 10 carbon atoms, and more preferably both (meth)acrylate monomer units having a chain alkyl group having 4 to 8 carbon atoms. If the composition for a nonaqueous secondary battery adhesive layer is of this type, it is possible to form a nonaqueous secondary battery adhesive layer that more firmly bonds battery components together even when pressurized at room temperature.

[0069] The (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the second particulate polymer is particularly preferably an n-butyl acrylate unit, since this allows for the formation of a non-aqueous secondary battery adhesive layer that further firmly bonds battery components together even when pressurized at room temperature. Here, when the (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the second particulate polymer is an n-butyl acrylate unit, it is preferable that the (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the first particulate polymer is also an n-butyl acrylate unit. That is, it is preferable that both the (meth)acrylate monomer unit having a chain alkyl group having 4 or more carbon atoms of the second particulate polymer and the first particulate polymer are n-butyl acrylate units. When the (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms of the first particulate polymer and the second particulate polymer are both n-butyl acrylate units, a nonaqueous secondary battery adhesive layer can be formed that further firmly bonds battery components together even when pressurized at room temperature.

[0070] The proportion of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the second particulate polymer is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 90% by mass or more, and preferably 99% by mass or less, and more preferably 95% by mass or less, when the total repeating units (total monomer units) contained in the second particulate polymer is taken as 100% by mass. When the proportion is equal to or greater than the lower limit, a nonaqueous secondary battery adhesive layer can be formed that more firmly bonds battery components together even under pressure at room temperature. Furthermore, when the proportion is equal to or greater than the lower limit, a secondary battery with excellent cycle characteristics can be obtained. On the other hand, when the proportion is equal to or less than the upper limit, inkjet ejection characteristics can be improved.

[0071] It is preferable that the second particulate polymer further contains a nitrile group-containing monomer unit. When the second particulate polymer contains a nitrile group-containing monomer unit, the ink jet discharge characteristics of the non-aqueous secondary battery adhesive layer composition can be improved. Furthermore, when the second particulate polymer contains a nitrile group-containing monomer unit, a non-aqueous secondary battery with excellent cycle characteristics can be obtained. Examples of the nitrile group-containing monomer unit include those listed above. The core polymer may contain one of the above-listed monomer units alone, or two or more of them in any ratio. It is preferable that the nitrile group-containing monomer unit is an acrylonitrile unit.

[0072] The proportion of the nitrile group-containing monomer units in the second particulate polymer is preferably 1% by mass or more, preferably 20% by mass or less, more preferably 15% 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 second particulate polymer. When the proportion of the nitrile group-containing monomer units in the second particulate polymer is equal to or greater than the above-mentioned lower limit, the inkjet ejection characteristics of the non-aqueous secondary battery adhesive layer composition can be further improved. Furthermore, when the proportion of the nitrile group-containing monomer units in the second particulate polymer is equal to or greater than the above-mentioned lower limit, a non-aqueous secondary battery with superior cycle characteristics can be obtained. On the other hand, when the proportion of the nitrile group-containing monomer units in the second particulate polymer is equal to or less than the above-mentioned upper limit, a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed, even when pressurized at room temperature.

[0073] The second particulate polymer may further contain, in addition to the (meth)acrylate monomer units having a chain alkyl group with 4 or more carbon atoms and the nitrile group-containing monomer units, the same monomer units as those exemplified as the monomer units contained in the first particulate polymer. Among them, the second particulate polymer preferably contains an aromatic vinyl monomer unit, a hydrophilic group-containing monomer unit, a crosslinkable monomer unit, and a (meth)acrylate monomer unit having a chain alkyl group with 3 or less carbon atoms. The polymer of the shell portion may contain one type of such monomer unit alone, or two or more types in any ratio.

[0074] As the aromatic vinyl monomer capable of forming an aromatic vinyl monomer unit, it is particularly preferred to use styrene. As the hydrophilic group-containing monomer capable of forming a hydrophilic group-containing monomer unit, it is preferred to use a monomer having a carboxylic acid group, more preferably a monocarboxylic acid, and particularly preferred to use at least one of acrylic acid and methacrylic acid. As the crosslinkable monomer capable of forming a crosslinkable monomer unit, it is preferred to use at least one monomer selected from the group consisting of a divinyl monomer, a di(meth)acrylic acid ester monomer, an ethylenically unsaturated monomer containing an epoxy group, and a (meth)acrylamide having a methylol group, and it is particularly preferred to use at least one compound selected from the group consisting of allyl methacrylate, ethylene glycol dimethacrylate, allyl glycidyl ether, and N-methylolacrylamide. As the (meth)acrylate monomer having a chain alkyl group having 3 or less carbon atoms capable of forming a (meth)acrylate monomer unit having a chain alkyl group having 3 or less carbon atoms, it is particularly preferred to use ethyl acrylate.

[0075] The proportion of the aromatic vinyl monomer units in the second particulate polymer 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, when the total repeating units (total monomer units) contained in the second particulate polymer is taken as 100% by mass. If the proportion of the aromatic vinyl monomer units is within the above range, a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed even when pressurized at room temperature.

[0076] The proportion of the hydrophilic group-containing monomer units in the second particulate polymer is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, and is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less, when the total repeating units (total monomer units) contained in the second particulate polymer is taken as 100% by mass. If the proportion of the hydrophilic group-containing monomer units is within the above range, the dispersibility of the second particulate polymer can be improved.

[0077] The proportion of the crosslinkable monomer units in the second particulate polymer 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, and is preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less, when the total repeating units (total monomer units) contained in the second particulate polymer is taken as 100% by mass. If the proportion of the crosslinkable monomer units is within the above range, a nonaqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed even when pressurized at room temperature.

[0078] The proportion of (meth)acrylate monomer units having a chain alkyl group having 3 or less carbon atoms in the second particulate polymer is preferably 1% by mass or more, more preferably 3% by mass or more, and is preferably 10% by mass or less, and more preferably 8% by mass or less, when all repeating units (total monomer units) contained in the second particulate polymer are taken as 100% by mass.

[0079] The content of the second particulate polymer in the non-aqueous secondary battery adhesive layer composition is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, and preferably 20 parts by mass or less, and more preferably 15 parts by mass or less, per 100 parts by mass of the first particulate polymer. When the content of the second particulate polymer in the non-aqueous secondary battery adhesive layer composition is within the above range, a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed even when pressurized at room temperature. Furthermore, when the content of the second particulate polymer in the non-aqueous secondary battery adhesive layer composition is within the above range, inkjet ejection characteristics can be improved.

[0080] The second particulate polymer may optionally further contain other monomer units as described above, provided that the object of the present invention is not impaired.

[0081] <Characteristics of the Second Particulate Polymer> The glass transition temperature of the second particulate polymer is preferably −50° C. or higher, more preferably −40° C. or higher, and preferably 10° C. or lower, more preferably −15° C. or lower, and even more preferably −25° C. or lower. If the glass transition temperature of the second particulate polymer 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 second particulate polymer is equal to or lower than the upper limit, the second particulate polymer can exhibit good adhesive properties, and a non-aqueous secondary battery adhesive layer that more firmly bonds battery components together can be formed even when pressurized at room temperature. The glass transition temperature of the second particulate polymer can be adjusted, for example, by changing the type and ratio of the monomers used to prepare the second particulate polymer.

[0082] The volume average particle diameter of the second particulate polymer 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 second particulate polymer is within the above-mentioned range, a nonaqueous secondary battery adhesive layer can be formed that more firmly bonds battery components together even when pressurized at room temperature.

[0083] <Preparation method of second particulate polymer> The second particulate polymer is not particularly limited, and for example, can be prepared 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 second particulate polymer.Then, the polymerization method and polymerization reaction are not particularly limited, and for example, known polymerization methods and polymerization reactions such as emulsion polymerization and suspension polymerization can be used.

[0084] <Solvent> The solvent for dispersing the first particulate polymer and the second particulate polymer is not particularly limited, and examples thereof include water, organic solvents, and mixtures thereof. Examples of organic solvents include, but are not limited to, cyclic aliphatic 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; and alcohols such as methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, and ethylene glycol monomethyl ether. A single solvent may be used, or two or more solvents may be used in any combination at any ratio. A mixture of water and an alcohol is preferably used as the solvent. Using a mixture of water and an alcohol can provide reliability, such as ejection stability, when the composition is used in an inkjet recording device. At least a portion of the solvent may be removed by drying or the like during the manufacturing process of a nonaqueous secondary battery laminate.

[0085] <Other Components> Other components optionally contained in the non-aqueous secondary battery adhesive layer composition of the present invention are not particularly limited, and examples thereof include surface tension modifiers, dispersants, viscosity modifiers, reinforcing materials, electrolyte additives, and the like. These 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. Note that these components may be used alone or in combination of two or more in any ratio.

[0086] (Method for preparing a composition for a non-aqueous secondary battery adhesive layer) The method for preparing the composition for a non-aqueous secondary battery adhesive layer of the present invention is not particularly limited, and can be prepared, for example, by stirring and mixing a first particulate polymer, a second particulate polymer, and any other components, preferably in the presence of a solvent. Here, the stirring and mixing method is not particularly limited, and can be performed by a known method. Specifically, a general stirring vessel, a ball mill, a sand mill, a bead mill, a pigment disperser, an ultrasonic disperser, a crusher, a homogenizer, a planetary mixer, a Filmix, etc. can be used. The mixing conditions are not particularly limited, but the mixture can usually be performed at a temperature ranging from room temperature to 80°C for 10 minutes to several hours.

[0087] (Adhesive Layer for Non-Aqueous Secondary Battery) 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. Here, 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. Therefore, the adhesive layer for a non-aqueous secondary battery of the present invention contains at least a first particulate polymer and a second particulate polymer, and optionally contains other components.

[0088] The first particulate polymer and the second particulate polymer are 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.

[0089] 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, a grid shape, etc. In particular, from the viewpoint of reducing the resistance of the secondary battery, it is preferable to form the adhesive layer in a dot shape. A dot-shaped adhesive layer can be obtained, for example, by an inkjet method using a coater (51 to 54 in FIG. 2) described later.

[0090] The diameter of the dots of 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 of the adhesive layer is equal to or greater than the above-mentioned lower limit, the adhesive strength between the electrode and the separator can be increased. On the other hand, if the diameter of the dots of the adhesive layer is equal to or less than the above-mentioned upper limit, deterioration of the cycle characteristics of the secondary battery can be suppressed.

[0091] 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.

[0092] The weight of the adhesive layer is 0.02 g / m ２ It is preferable that the content is 1.0 g / m or more. ２ Preferably, the content 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, which ensures sufficient adhesive strength between the electrode and the separator. Also, the adhesive layer has a basis weight of at most the above upper limit, which ensures sufficiently high cycle characteristics of the secondary battery.

[0093] 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. When the coverage of the adhesive layer is equal to or greater than the lower limit, the adhesive strength between the electrode and the separator can be ensured. When the coverage of the adhesive layer is equal to or less than the upper limit, the cycle characteristics of the secondary battery can be sufficiently high.

[0094] Here, the "coverage rate of the adhesive layer" on a certain surface or region refers to the ratio of the area of ​​the portion covered with the adhesive layer to the total area of ​​the surface or region [(area of ​​the portion covered with the adhesive layer / total area of ​​the surface or region) x 100 (%)]. When a composition for adhesive layer containing a first particulate polymer, a second 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 adhesive layer.

[0095] The coverage of the adhesive layer can be adjusted by changing the arrangement pattern of the adhesive layer arranged (coated) in each region. Specifically, when 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 orthogonal 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 according to the following formula (2): Coverage of adhesive layer = {πr ２ / (x・y)}×100(%)...(2)

[0096] (Method for Producing 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 to a substrate (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 the non-aqueous secondary battery adhesive layer formed on the substrate after the drying step (peeling step). Here, when the adhesive layer for a non-aqueous secondary battery is formed on an electrode substrate or separator substrate as a substrate, the electrode substrate and the separator substrate can be directly bonded 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 peeled from the release agent and then used to adhere the electrode substrate and the separator substrate.

[0097] <Coating Process> In the coating process, the nonaqueous secondary battery adhesive layer composition of the present invention is coated onto a substrate such as an electrode substrate, a separator substrate, or a release substrate. Examples of coating methods include an inkjet method performed through a nozzle of a coating machine. Because the nonaqueous secondary battery adhesive layer composition of the present invention has excellent inkjet ejection characteristics, coating is preferably performed by an inkjet method. Conventional inkjet coating machines can be used, and coating can be performed using, for example, the coating machines described below (51 to 54 in FIG. 2). From the perspective of production efficiency, the nonaqueous secondary battery adhesive layer composition is preferably coated onto an electrode substrate or a separator substrate. From the perspective of facilitating a drying process, the nonaqueous secondary battery adhesive layer composition is preferably coated onto an electrode substrate. Coating conditions using the inkjet method are not particularly limited as long as they allow the nonaqueous secondary battery adhesive layer composition to be coated onto a substrate, and can be appropriately adjusted depending on the desired shape of the resulting adhesive layer (e.g., planar view shape, dot diameter, dot thickness, dot pitch, coverage, and basis weight).

[0098] [Electrode substrate] The electrode substrate is not particularly limited, and a known electrode substrate can be used. For example, the electrode substrate can be an electrode composed of an electrode substrate in which an electrode mixture layer is formed on one or both sides of a current collector, or an electrode in which a porous membrane layer is further formed on the electrode mixture layer of the 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.

[0099] [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, etc., with polyethylene microporous membranes and nonwoven fabrics being preferred due to their excellent strength. From the standpoint of safety, heat-resistant separators in which ceramic is applied to the separator are also preferred. The separator substrate may also have a porous membrane layer formed on one or both sides. The porous membrane layer refers to a layer containing non-conductive particles, as described, for example, in JP 2013-145763 A.

[0100] [Release Substrate] The release substrate is not particularly limited, and known ones can be used.

[0101] <Drying step> In the drying step, the adhesive layer composition coated on the substrate is dried to form an adhesive layer made of the dried adhesive layer composition on the substrate. The drying method is not particularly limited and known methods can be used, and examples of the drying method include drying methods using heating devices such as heaters, dryers, and heat rollers. 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.

[0102] <Peeling Step> 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.

[0103] (Laminate for Non-Aqueous Secondary Battery) The laminate for a non-aqueous secondary battery of the present invention includes an electrode and a separator, and the electrode and separator are bonded together via the adhesive layer for a non-aqueous secondary battery of the present invention. Because the electrode and separator are bonded together via the adhesive layer for a non-aqueous secondary battery of the present invention, the laminate for a non-aqueous secondary battery of the present invention exhibits excellent adhesion between battery components. The electrode bonded to the separator to form the laminate for a non-aqueous secondary battery may be only a positive electrode, only a negative electrode, or both a positive electrode and a negative electrode. Furthermore, when both a positive electrode and a negative electrode are bonded to a separator to obtain a laminate for a non-aqueous secondary battery, the number of positive electrodes, negative electrodes, and separators in the laminate for a non-aqueous secondary battery may each be one, or two or more. In other words, the structure of the laminate for a non-aqueous secondary battery 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 electrodes and negative electrodes are alternately stacked with separators interposed therebetween (for example, "separator / negative electrode / separator / positive electrode / separator / negative electrode... / separator / positive electrode" etc.)

[0104] <Electrode> The electrode is not particularly limited, and a known electrode can be used. For example, the electrode described in the section "Method for producing an adhesive layer for a non-aqueous secondary battery" can be used.

[0105] <Separator> The separator is not particularly limited, and known separators can be used. For example, those described in the section "Method for producing adhesive layer for non-aqueous secondary battery" can be used.

[0106] <Adhesive Layer> The adhesive layer that bonds the electrode and the separator is a dried product of the composition for adhesive layers for non-aqueous secondary batteries of the present invention. That is, the dried product contains at least a polymer derived from the first particulate polymer and the second particulate polymer, and optionally contains the other components described above. Furthermore, the preferred form of the adhesive layer (dot diameter, dot thickness, dot pitch, coverage, basis weight, etc.) is the same as that described in the "Adhesive Layer for Non-aqueous Secondary Battery" section. Furthermore, the first particulate polymer and the second particulate polymer exist in particulate form in the composition for adhesive layers for non-aqueous secondary batteries, but may be in particulate form or any other form in the adhesive layer for non-aqueous secondary batteries in the laminate.

[0107] (Method for manufacturing a laminate for a non-aqueous secondary battery) The method for manufacturing a laminate for a non-aqueous secondary battery of the present invention includes a step of supplying an adhesive material to the bonding surfaces of at least one of the electrode and the separator (i.e., the surfaces 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 via the bonding surfaces to which the adhesive material has been supplied (bonding step). Furthermore, the method for manufacturing a laminate for a non-aqueous secondary battery of the present invention may include a step of cutting the resulting bonded body after the bonding step (cutting step).

[0108] <Supplying Step> 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 supplying of the adhesive material is not particularly limited, and can be carried out, for example, by applying the non-aqueous 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 non-aqueous secondary battery adhesive layer obtained by peeling it from the release substrate as described above onto the bonding surface.

[0109] 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 adhesive material to be obtained (planar view shape, dot diameter, dot thickness, dot pitch, coverage, basis weight, etc.).

[0110] 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 this specification, the "lamination start position" refers to the position where the lamination surface of the electrode and the lamination surface of the separator come into contact when laminating the electrode and the separator.

[0111] The conveyance of the electrodes and separators is not particularly limited, and can be carried out using any conveyance mechanism, such as 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 convey at least one of the electrodes and the separators using rollers.

[0112] The drying of the non-aqueous secondary battery adhesive layer composition is not particularly limited, and can be carried out using a heating device such as a heater, a dryer, or a heat roller. The temperature during drying of the electrode and / or separator to which the non-aqueous secondary battery adhesive layer composition has been supplied 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.

[0113] <Bonding Step> In the bonding step, the electrode and the separator are bonded together via their bonding surfaces by applying pressure to the laminate of the electrode and the separator that are superposed on each other via their bonding surfaces.

[0114] The temperature at which the laminate is pressed is not particularly limited as long as it is a temperature at which the electrodes and the separator can be bonded together, but is preferably 0° C. or higher, more preferably 10° C. or higher, even more preferably 20° C. or higher, and preferably 35° C. or lower, more preferably 30° C. or lower, and even more preferably 25° C. or lower. If the pressing temperature for the laminate is equal to or higher than the lower limit, the adhesion between the battery components can be improved. On the other hand, if the pressing temperature for the laminate is equal to or lower than the upper limit, the manufacturing efficiency of the laminate can be increased.

[0115] The laminate is pressurized at a pressure of preferably 0.1 MPa or more, more preferably 0.5 MPa or more, and preferably 5 MPa or less. When the laminate is pressurized at a pressure equal to or greater than the above-mentioned lower limit, the adhesion between the battery components can be improved. On the other hand, when the laminate is pressurized at a pressure equal to or less than the above-mentioned upper limit, deformation of the laminate (such as crushing of the electrode mixture layer or separator) can be effectively suppressed.

[0116] The pressurization time for the laminate is preferably 20 seconds or less, more preferably 15 seconds or less. When the pressurization time for the laminate is equal to or less than the above upper limit, the production efficiency of the laminate can be improved.

[0117] <Cutting Step> The cutting step is a step of cutting the bonded body obtained in the bonding step to a desired size. For example, any cutting machine that can be used in the field of secondary battery manufacturing can be used, such as a cutting machine that sandwiches the bonded body with cutting blades from both sides in the thickness direction of the bonded body to cut it.

[0118] [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 in the section "Method for producing an adhesive layer for a non-aqueous secondary battery" can be used.

[0119] [Adhesive Material] The adhesive material for bonding an electrode and a separator is a dried product of the composition for a non-aqueous secondary battery adhesive layer of the present invention. That is, the dried product contains at least a polymer derived from the first particulate polymer and the second particulate polymer, and optionally contains the other components described above. Furthermore, the preferred form of the adhesive material (dot diameter, dot thickness, dot pitch, coverage, basis weight, etc.) is the same as that described in the "Adhesive Layer for a Non-aqueous Secondary Battery" section. Furthermore, the first particulate polymer and the second particulate polymer exist 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.

[0120] An example of a manufacturing process for a nonaqueous secondary battery laminate of the present invention will be described below with reference to FIG. 2 . 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, via 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 blank 20A via 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 the negative electrode blank 20A via an adhesive material supplied from a coater 53, thereby obtaining a bonded assembly including positive electrodes. 2, an adhesive material is supplied from a coater 54 to the surface of the second separator raw sheet 30A opposite to the negative electrode raw sheet 20A side, and the laminate is cut between longitudinally adjacent positive electrodes 40 to obtain a laminate, which is then stacked to produce a laminate. The laminate is then cut using a cutter 70 to obtain a laminate.

[0121] (Nonaqueous 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 has excellent adhesion between battery components.

[0122] <Electrode> The electrode used in the secondary battery of the present invention is not limited, and a known electrode can be used, for example, the one described in the section "Method for producing an adhesive layer for a non-aqueous secondary battery."

[0123] <Separator> The separator used in the secondary battery of the present invention is not limited, and known separators can be used, for example, those described in the section "Method for producing adhesive layer for non-aqueous secondary battery" can be used.

[0124] <Electrolyte> The electrolyte used in the secondary battery of the present invention is usually 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 the lithium salt include LiPF ６ , LiAsF ６ , LiBF ４ , LiSbF ６ , LiAlCl ４ , LiClO ４ , C.F. ３ SO ３ Li, C ４ F ９ SO ３ Li, CF ３ COOLi, (CF ３ CO) ２ NLi, (CF ３ SO ２ ) ２ NLi, (C ２ F ５ SO ２ Among them, LiPF is preferred because it is easily soluble in solvents and shows a high degree of dissociation. ６, LiClO ４ , C.F. ３ SO ３ Li is preferred, and LiPF ６ is particularly preferred. Note that one type of electrolyte may be used alone, or two or more types may be used in combination in any ratio. Generally, 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.

[0125] The organic solvent used in the electrolyte is not particularly limited as long as it can dissolve the supporting electrolyte. For example, carbonates such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), and ethyl methyl carbonate (EMC) are preferably used. Other suitable solvents include 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 they have a high dielectric constant and a wide stable potential range, and a mixture of ethylene carbonate and ethyl methyl carbonate is even more preferred. Known additives, such as vinylene carbonate (VC), fluoroethylene carbonate (FEC), and ethyl methyl sulfone, may also be added to the electrolyte.

[0126] (Method for Manufacturing Nonaqueous Secondary Battery) The nonaqueous secondary battery of the present invention can be manufactured, for example, by stacking laminates to form a stack, which can 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. The stack may also be manufactured 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 an overcurrent protection element such as a fuse or a PTC element, an expanded metal, a lead plate, etc., as necessary to prevent internal pressure buildup, overcharging and overdischarging, etc. The shape of the secondary battery may be, for example, a coin type, a button type, a sheet type, a cylindrical type, a rectangular type, a flat type, etc.

[0127] The present invention will be described in detail 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 that certain monomer to all monomers used in the polymerization of the polymer, unless otherwise specified. Various measurements and evaluations in the examples and comparative examples were performed by the following methods.

[0128] <Glass Transition Temperature> The aqueous dispersion of the first particulate polymer and the aqueous dispersion of the second particulate polymer prepared in each Production Example were each dried at a temperature of 130°C for 1 hour to prepare a sample. 10 mg of the measurement sample was weighed into an aluminum pan, and measurement was carried out using a differential scanning calorimetry measuring device ("EXSTAR DSC6220" manufactured by SII NanoTechnology Inc.) at a measurement temperature range of -100°C to 200°C at a heating rate of 10°C / min under the conditions specified in JIS Z8703 to obtain a differential scanning calorimetry (DSC) curve. An empty aluminum pan was used as a reference. During this heating process, the glass transition temperature (°C) was determined as the intersection point between the baseline immediately before the endothermic peak of the DSC curve at which the differential signal (DDSC) was 0.05 mW / min / mg or more appeared and the tangent to the DSC curve at the first inflection point that appeared after the endothermic peak.

[0129] <Volume average particle diameter> The volume average particle diameter of the first particulate polymer and the second particulate polymer prepared in each Production Example was measured by a laser diffraction method. Specifically, an aqueous dispersion solution (solid content concentration 0.1% by mass) containing the prepared first particulate polymer or the second particulate polymer was used as a sample, and the volume average particle diameter D50 (nm) was determined as the particle diameter at which the cumulative volume calculated from the smallest diameter side became 50% in the particle size distribution (volume basis) obtained using a laser diffraction particle size distribution analyzer (manufactured by Beckman Coulter, Inc., product name "LS-13 320").

[0130] <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 at a temperature of 25°C and a pressure of 1 MPa for 10 seconds. The resulting laminate (i.e., a laminate in which one negative electrode and one separator were bonded together via the adhesive material) was collected and used as a test specimen. This test specimen was placed with the negative electrode current collector side facing downward, and cellophane tape was attached to the negative electrode current collector side surface. 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 was measured. This measurement was performed a total of six times, and the average stress was calculated as the peel strength. The adhesion between the negative electrode and the separator was evaluated according to the following criteria. A higher peel strength indicates a higher adhesiveness between the electrode (negative electrode) and the separator. A: Peel strength is 5.0 N / m or more B: Peel strength is 4.0 N / m or more and less than 5.0 N / m C: Peel strength is 3.0 N / m or more and less than 4.0 N / m D: Peel strength is 2.0 N / m or more and less than 3.0 N / m E: Peel strength is 1.0 N / m or more and less than 2.0 N / m F: Peel strength is less than 1.0 N / m

[0131] <Inkjet Discharge Characteristics> A discharge test was carried out on the non-aqueous secondary battery adhesive layer compositions produced in each Example and Comparative Example using a high-performance head-mounted discharge test kit (IJK-200S, manufactured by Microjet Co., Ltd.). The discharge characteristics were evaluated according to the following criteria: A: Dischargeable, and re-dischargeable even after standing for 5 minutes or more B: Dischargeable, but not re-dischargeable after standing for 5 minutes C: Dischargeable

[0132] <Cycle Characteristics> The fabricated lithium ion secondary batteries were charged to 4.3 V at a constant current and constant voltage (CCCV) in an atmosphere at 25°C to prepare cells. The prepared cells were discharged to 3.0 V at a constant current 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 calculated. These measurements were performed on five lithium ion secondary battery cells, and the average value was taken as the discharge capacity retention rate. Next, these lithium ion secondary batteries were clamped with a pressure jig to apply a surface pressure of 1 MPa, and then subjected to a cycle test at 45°C. The cycle test conditions were 1 C CC+CV charge (4.3 V, 1 / 50 C cut) and 1 C CC discharge (3.0 V cut), and the charge / discharge cycle was repeated 500 times. Thereafter, the temperature was lowered to 25°C while the pressure jig was still fastened, and the discharge capacity retention rate was determined in the same manner as above. The retention rate (%) before and after the cycle (= discharge capacity retention rate after cycle test / discharge capacity retention rate before cycle test x 100) was calculated and evaluated according to the following criteria. The higher the retention rate before and after the cycle, the smaller the increase in resistance in the cycle test, i.e., the more excellent the cycle characteristics. A: retention rate 80% or more B: retention rate 60% or more but less than 80% C: retention rate 40% or more but less than 60% D: retention rate less than 40%

[0133] (Production Example 1) <Production of First Particulate Polymer 1> 100 parts of ion-exchanged water and 0.1 parts of ammonium persulfate were each supplied to 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, 40 parts of ion-exchanged water, 0.2 parts of sodium dodecylbenzenesulfonate as an emulsifier, 90.9 parts of n-butyl acrylate as a (meth)acrylate monomer having a chain alkyl group of 4 or more carbon atoms, 2 parts of methacrylic acid as a hydrophilic group-containing monomer, and 0.1 parts of ethylene glycol dimethacrylate as a crosslinkable monomer, and 2 parts of acrylonitrile as a nitrile group-containing monomer were mixed to obtain a core-forming monomer composition. This core-forming monomer composition was continuously added to the reactor over 3 hours, and a polymerization reaction was carried out at a temperature of 80 ° C. The polymerization was continued until the polymerization conversion rate reached 95%, thereby obtaining an aqueous dispersion containing a particulate polymer constituting the core portion. Next, a monomer composition for forming a shell portion, containing 4.75 parts of styrene as an aromatic monovinyl monomer and 0.25 parts of methacrylic acid as a hydrophilic group-containing monomer, was continuously supplied to this aqueous dispersion over 60 minutes, and polymerization was continued. The reaction was stopped by cooling when the polymerization conversion rate reached 98%, thereby preparing an aqueous dispersion containing a first particulate polymer 1. The volume average particle size and glass transition temperature of the obtained first particulate polymer 1 were measured. The results are shown in Table 1. Furthermore, by observing the cross-sectional structure of the first particulate polymer 1 using a transmission electron microscope (TEM), it was confirmed that the first particulate polymer 1 had a core-shell structure in which the shell portion partially covered the outer surface of the core portion.

[0134] (Production Examples 2 to 15) <Production of First Particulate Polymers 2 to 15> Aqueous dispersions of first particulate polymers 2 to 15 having a core-shell structure were prepared in the same manner as in the production of first particulate polymer 1, except that the types of monomers and the amounts used were changed as shown in Table 1. Then, various measurements were carried out in the same manner as in Production Example 1. The results are shown in Table 1.

[0135] (Production Example 16) <Production of Second Particulate Polymer 1> 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 each supplied to a reactor equipped with a stirrer, the gas phase was replaced with nitrogen gas, and the temperature was raised to 70 ° C. Meanwhile, in a separate vessel, 50 parts of ion-exchanged water, 0.1 parts of sodium dodecylbenzenesulfonate as an emulsifier, 93.8 parts of n-butyl acrylate as a (meth)acrylate monomer having a chain alkyl group having 4 or more carbon atoms, 2 parts of methacrylic acid as a hydrophilic group-containing monomer, 1.2 parts of N-methylmethylolamide as a crosslinkable monomer, 1 part of allyl glycidyl ether, and 2 parts of acrylonitrile as a nitrile 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 addition, the reaction was carried out at 80°C. After the addition was completed, the mixture was stirred at 80°C for an additional 3 hours to terminate the reaction, thereby producing an aqueous dispersion containing a second particulate polymer 1 having no core-shell structure. Various measurements were then carried out in the same manner as in Production Example 1. The results are shown in Table 2.

[0136] (Production Examples 17 to 28) <Production of Second Particulate Polymers 2 to 13> Aqueous dispersions of second particulate polymers 2 to 13 having a core-shell structure were prepared in the same manner as in the production of second particulate polymer 1, except that the types of monomers and the amounts used were changed as shown in Table 2. Then, various measurements were carried out in the same manner as in Production Example 1. The results are shown in Table 2.

[0137] In Tables 1 and 2 below, "BA" represents n-butyl acrylate, "2EHA" represents 2-ethylhexyl acrylate, "DA" represents n-dodecyl acrylate, "PA" represents n-propyl acrylate, "MAA" represents methacrylic acid, "EDMA" represents ethylene glycol dimethacrylate, "AN" represents acrylonitrile, "St" represents styrene, "AA" represents acrylic acid, "AMA" represents allyl methacrylate, "N-MA" represents N-methylolacrylamide, "AGE" represents allyl glycidyl ether, "EA" represents ethyl acrylate, "Aam" represents acrylamide, "Proportion A" represents the proportion of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the first particulate polymer, "Ratio α" indicates the ratio of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the core polymer, "Tg" indicates the glass transition temperature, and "Ratio B" indicates the ratio of (meth)acrylate monomer units having a chain alkyl group having 4 or more carbon atoms in the second particulate polymer.

[0138]

[0139]

[0140] Example 1 Preparation of a Non-Aqueous Secondary Battery Adhesive Layer Composition The aqueous dispersion of the first particulate polymer 1 obtained in Production Example 1 and the aqueous dispersion of the second particulate polymer 1 obtained in Production Example 16 were mixed so that the mass ratio of solid contents was 100:10, and ion-exchanged water was added to dilute the mixture to a solid content concentration of 10.5%. Propylene glycol was further added to the resulting mixture to adjust the solid content concentration to 10%, thereby obtaining a non-aqueous secondary battery adhesive layer composition. The resulting adhesive layer composition was used to evaluate the adhesive strength between the electrode and separator and the inkjet ejection characteristics. The results are shown in Table 3.

[0141] <Preparation of Negative Electrode Raw Material> 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 were placed in a 5 MPa pressure vessel equipped with a stirrer, and after thorough stirring, the mixture was heated to 50 ° C to initiate polymerization. When the polymerization conversion rate reached 96%, the reaction was stopped by cooling, and a mixture containing a binder (SBR) for the negative electrode composite layer was obtained. A 5% aqueous sodium hydroxide solution was added to the mixture containing the binder for the negative electrode composite layer, and the pH was adjusted to 8. Unreacted monomers were removed by heated vacuum distillation. The mixture was then cooled to a temperature of 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 of a 2% aqueous solution of carboxymethylcellulose sodium salt (manufactured by Nippon Paper Industries Co., Ltd., product name "MAC350HC") as a viscosity modifier, in terms of solid content, and ion-exchanged water were mixed to adjust the solid content concentration to 68%, and then further mixed at a temperature of 25 ° C. for 60 minutes. Furthermore, the solid content concentration was adjusted to 62% with ion-exchanged water, and then further mixed at a temperature of 25 ° C. for 15 minutes. To the resulting mixture, 1.5 parts of the aqueous dispersion containing the binder for the negative electrode composite layer and ion-exchanged water were added in terms of solid content, and the final solid content was adjusted to 52%, and then further mixed for 10 minutes. This 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, the copper foil was heat-treated 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.

[0142] <Preparation of Positive Electrode Raw Sheet> LiCoO having a volume average particle diameter of 12 μm was used as the positive electrode active material. ２100 parts of the above, 2 parts of acetylene black (manufactured by Denka Co., Ltd., product name "HS-100") as a conductive material, 2 parts of polyvinylidene fluoride (manufactured by Kureha Corporation, product name "#7208") as a binder, equivalent to the solid content, and N-methylpyrrolidone as a solvent were mixed to a total solids concentration of 70%. These were mixed using a planetary mixer to obtain a slurry composition for a non-aqueous secondary battery positive electrode. The obtained slurry composition for a non-aqueous secondary battery positive electrode was applied to both sides of a 20 μm thick aluminum foil current collector using a comma coater so that the film thickness after drying 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 heat-treated 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.

[0143] <Preparation of Separator Raw Material> A separator raw material made of polyethylene (PE) (product name "ND412" manufactured by Asahi Kasei) was prepared.

[0144] <Production of Laminate> A laminate was produced using the prepared adhesive layer composition, negative electrode raw sheet, positive electrode raw sheet, and separator raw sheet 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 a negative electrode raw sheet 20A unwound from a negative electrode raw sheet roll was conveyed at a speed of 10 m / min, an adhesive layer composition was supplied from an inkjet head of an inkjet coater 52 (Konica Corporation, KM1024 (shear mode type)) onto one surface of the negative electrode raw sheet 20A, and a second separator raw sheet 30A unwound from a separator raw sheet roll and the negative electrode raw sheet 20A were bonded together using pressure rollers 61 and 62. An adhesive layer composition was supplied from the inkjet head of an inkjet coater 51 (Konica Corporation, KM1024 (shear mode type)) onto the other surface of the negative electrode raw sheet 20A, and the first separator raw sheet 10A unwound from the separator raw sheet roll and the laminate of the negative electrode raw sheet 20A and the second separator raw sheet 30A were bonded together with pressure rollers 61 and 62. Furthermore, an adhesive layer composition was supplied from the inkjet head of an inkjet coater 53 (Konica Corporation, KM1024 (shear mode type)) onto the surface of the first separator raw sheet 10A opposite to the negative electrode raw sheet 20A side, and after placing the pre-cut positive electrode 40 thereon, the laminate of the first separator raw sheet 10A, the negative electrode raw sheet 20A, and the second separator raw sheet 30A and the positive electrode 40 were bonded together with pressure rollers 61 and 62. The adhesive layer composition was then supplied onto the positive electrode 40 from the inkjet head of an inkjet coater 54 (Konica, KM1024 (shear mode type)), and then cut with a cutter 70 to obtain a laminate in which the second separator, negative electrode, first separator, and positive electrode were laminated in this order. The ends of the current collectors of the positive electrode 40 and the negative electrode roll 20A were provided with portions where no electrode composite layer (positive electrode composite layer or negative electrode composite layer) was formed, and these portions were punched out in advance to form tabs of the desired size. The lamination was performed so that the positive electrode tab and the negative electrode tab were located on the same edge side of the lamination surfaces X and Y between the electrode and separator. The lamination using pressure rollers 61 and 62 was performed at a temperature of 25°C and a pressure of 1 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).

[0145] 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 spacing between dots was 400 μm. The basis weight of the adhesive material was 0.2 g / m ２ The coverage was measured and found to be 6.5%.

[0146] <Manufacture of Secondary Battery> Five of the laminates prepared above were stacked and pressed at a temperature of 25° C. and a pressure of 2 MPa for 10 seconds to prepare a stack, which was then wrapped in an aluminum packaging exterior as an exterior. An electrolyte solution (solvent: ethylene carbonate / diethyl carbonate / vinylene carbonate = 68.5 / 30 / 1.5 (volume ratio), electrolyte: LiPF with a concentration of 1 M) was added to the stack. ６ ) was poured into the battery. The opening of the aluminum packaging was then heat-sealed at 150°C to produce a stacked lithium-ion secondary battery with a capacity of 800 mAh. The cycle characteristics of the resulting secondary battery were evaluated. The results are shown in Table 3.

[0147] (Examples 2 to 15, Comparative Examples 1 to 6) Various operations, measurements, and evaluations were performed in the same manner as in Example 1, except that the type of the first particulate polymer, the type of the second particulate polymer, and the use ratio thereof were changed as shown in Table 3. The results are shown in Table 3.

[0148] In Table 3 below, "Ratio X" indicates the content ratio of the first particulate polymer in the total mass of the first particulate polymer and the second particulate polymer, and "Ratio Y" indicates the content ratio of the second particulate polymer in the total mass of the first particulate polymer and the second particulate polymer.

[0149]

[0150] The evaluation results shown in Table 3 demonstrate that the nonaqueous secondary battery adhesive layer composition of the present invention can form a nonaqueous secondary battery adhesive layer that firmly bonds battery components together even at room temperature under pressure. Furthermore, as can be seen from the evaluation results shown in Table 3, the nonaqueous secondary battery adhesive layer composition of the present invention has excellent inkjet ejection characteristics. Furthermore, as can be seen from the evaluation results shown in Table 3, the nonaqueous secondary battery obtained using the nonaqueous secondary battery adhesive layer composition of the present invention has excellent cycle characteristics.

[0151] According to the present invention, a composition for a non-aqueous secondary battery adhesive layer can be provided, which can form a non-aqueous secondary battery adhesive layer that firmly bonds battery components together even at room temperature and under pressure. Furthermore, according to the present invention, a non-aqueous secondary battery adhesive layer and a method for manufacturing the same can be provided, which can firmly bond battery components together even at room temperature and under pressure. Furthermore, according to the present invention, a non-aqueous secondary battery laminate that exhibits excellent adhesion between battery components and a method for manufacturing the same can be provided. Furthermore, according to the present invention, a non-aqueous secondary battery exhibits excellent adhesion between battery components can be provided.

[0152] 10A First separator raw sheet 20A Negative electrode raw sheet 30A Second separator raw sheet 40 Positive electrode 50 Droplets 51 to 54 Coating machine (nozzle head) 61, 62 Pressure roller 70 Cutter 91 Conveyor roller 92 Heat roller 300 First particulate polymer 310 Core portion 310S Outer surface of core portion 320 Shell portion

Claims

1. A composition for a non-aqueous secondary battery adhesive layer, comprising a first particulate polymer and a second particulate polymer different from the first particulate polymer, wherein the first particulate polymer has a core-shell structure including a core portion and a shell portion covering at least a part of the outer surface of the core portion, both the polymer of the core portion and the second particulate polymer contain a (meth)acrylate monomer unit having a chain alkyl group with 4 or more carbon atoms, when the proportion of the (meth)acrylate monomer unit having a chain alkyl group with 4 or more carbon atoms in the first particulate polymer is A mass%, the proportion of the (meth)acrylate monomer unit having a chain alkyl group with 4 or more carbon atoms in the second particulate polymer is B mass%, the content ratio of the first particulate polymer in the total mass of the first particulate polymer and the second particulate polymer is X mass%, and the content ratio of the second particulate polymer in the total mass of the first particulate polymer and the second particulate polymer is Y mass%, the following formula (1): (AX + BY) / (X + Y) ··· (1) A composition for a non-aqueous secondary battery adhesive layer, wherein the value calculated by the formula is 75 mass% or more.

2. The glass transition temperature of the polymer of the core portion is -20°C or lower, The glass transition temperature of the second particulate polymer is -15°C or lower. The composition for a non-aqueous secondary battery adhesive layer according to Claim 1.

3. The glass transition temperature of the polymer of the shell portion is 50°C or higher. The composition for a non-aqueous secondary battery adhesive layer according to Claim 1.

4. The mass ratio of the shell portion in the first particulate polymer is 2 mass% or more and 15 mass% or less. The composition for a non-aqueous secondary battery adhesive layer according to Claim 1.

5. When the proportion of the (meth)acrylate monomer unit having a chain alkyl group with 4 or more carbon atoms in the polymer of the core portion is 100 mass% based on all the monomer units contained in the core portion, it is 90 mass% or more, When the proportion of the (meth)acrylate monomer unit having a chain alkyl group with 4 or more carbon atoms in the second particulate polymer is 100 mass% based on all the monomer units contained in the second particulate polymer, it is 75 mass% or more. The composition for a non-aqueous secondary battery adhesive layer according to Claim 1.

6. The non-aqueous secondary battery adhesive layer composition according to claim 1, wherein the structural formula of the (meth)acrylate monomer unit having a chain alkyl group with 4 or more carbon atoms in the second particulate polymer is the same as the structural formula of the (meth)acrylate monomer unit having a chain alkyl group with 4 or more carbon atoms in the first particulate polymer.

7. The non-aqueous secondary battery adhesive layer composition according to claim 1, wherein the (meth)acrylate monomer units having a chain alkyl group with 4 or more carbon atoms in the first particulate polymer and the second particulate polymer are both (meth)acrylate monomer units having a chain alkyl group with 4 or more and 10 or less carbon atoms.

8. The non-aqueous secondary battery adhesive layer composition according to claim 1, wherein the (meth)acrylate monomer units having a chain alkyl group with 4 or more carbon atoms in the first particulate polymer and the second particulate polymer are both n-butyl acrylate units.

9. The non-aqueous secondary battery adhesive layer composition according to claim 1, wherein at least one of the first particulate polymer and the second particulate polymer further contains a nitrile group-containing monomer unit.

10. An adhesive layer for a non-aqueous secondary battery, which is formed by using the non-aqueous secondary battery adhesive layer composition according to any one of claims 1 to 9.

11. A step of coating the non-aqueous secondary battery adhesive layer composition according to any one of claims 1 to 9 on a substrate; A step of drying the non-aqueous secondary battery adhesive layer composition coated on the substrate; A method for manufacturing an adhesive layer for a non-aqueous secondary battery, which includes the above steps.

12. A laminate for a non-aqueous secondary battery, which includes an electrode and a separator, The laminate for a non-aqueous secondary battery, wherein the electrode and the separator are adhered via the non-aqueous secondary battery adhesive layer according to claim 10.

13. A step of supplying an adhesive material to at least one bonding surface of the electrode and the separator; A step of pressing and bonding the electrode and the separator via the bonding surface to which the adhesive material has been supplied; including A method for manufacturing a laminate for a non-aqueous secondary battery, wherein the adhesive material is formed by using the non-aqueous secondary battery adhesive layer composition according to any one of claims 1 to 9.

14. A non-aqueous secondary battery, which includes the laminate for a non-aqueous secondary battery according to claim 12.