Composite particles, binder composition for non-aqueous secondary batteries, and non-aqueous secondary battery electrode

Abstract

A composite particle containing a copolymer having a first structural unit derived from a monomer (a1) and a second structural unit derived from a monomer (a2), the monomer (a1) being a nonionic compound having only one ethylenically unsaturated bond, and the monomer (a2) being a compound having a carboxyl group and only one ethylenically unsaturated bond, and a polyrotaxane, the polyrotaxane is provided with a cyclic molecule having a cyclic skeleton and a chain molecule penetrating through an opening of the cyclic molecule and having a blocking group at both ends, and does not contain an ethylenically unsaturated bond.

Description

Technical Field

[0001] The present invention relates to composite particles, an adhesive composition for non-aqueous secondary batteries, a slurry for non-aqueous secondary battery electrodes, a non-aqueous secondary battery electrode, a non-aqueous secondary battery, and a method for manufacturing the composite particles.

[0002] This application claims priority based on Japanese Patent Application No. 2022-202378 filed on December 19, 2022, and incorporates its content herein. Background Art

[0003] Non-aqueous secondary batteries can be miniaturized and light-weighted, and thus are widely used as power sources for notebook personal computers, mobile phones, power tools, electronic / communication devices, etc. In recent years, non-aqueous secondary batteries are also used as power sources for electric vehicles, hybrid vehicles, etc. As a representative example of non-aqueous secondary batteries, a lithium-ion secondary battery can be cited.

[0004] A non-aqueous secondary battery includes a positive electrode using a metal oxide or the like as an active material, a negative electrode using a carbon material such as graphite as an active material, and an electrolyte. The positive electrode and the negative electrode include a current collector and an electrode active material layer formed on the current collector. In the electrode active material layer, an adhesive that bonds the active materials to each other and the active material to the current collector to fix the electrode active material layer to the current collector is usually included.

[0005] Conventionally, as adhesives used in non-aqueous secondary batteries, the substances described in Patent Document 1 and Patent Document 2 are known.

[0006] Patent Document 1 describes an adhesive composition for secondary battery electrodes, which contains at least 100 parts by mass of a polymer aqueous dispersion selected from styrene-butadiene copolymer latex and acrylic emulsion, and 1 to 20 parts by mass of a nonionic surfactant.

[0007] Patent Document 2 describes an adhesive for lithium-ion secondary battery electrodes having a glass transition temperature of 30°C or lower, which is obtained by emulsion polymerization of an ethylenically unsaturated monomer containing 15 to 70% by mass of styrene, an ethylenically unsaturated carboxylic acid ester, an ethylenically unsaturated carboxylic acid, and an internal crosslinking agent as essential components in the presence of a surfactant.

[0008] In addition, a resin emulsion for coatings that can be suitably used for exterior building coatings and the like is described in Patent Document 3. A resin emulsion for coatings is disclosed in Patent Document 3. The glass transition temperature of the resin constituting the resin emulsion for coatings is 0°C or higher, and it contains 0.01 to 4% by mass of structural units derived from a modified polyrotaxane. The modified polyrotaxane has a structure in which a functional group having a radical polymerizable group is bonded to the cyclic molecule of a polyrotaxane having a cyclic molecule and an opening penetrating the cyclic molecule and having blocking groups at both ends.

[0009] Prior Art Documents

[0010] Patent Documents

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-239070 (A)

[0012] Patent Document 2: Japanese Patent Application Laid-Open No. 2011-243464 (A)

[0013] Patent Document 3: Japanese Patent Application Laid-Open No. 2019-116594 (A) Summary of the Invention

[0014] Problems to be Solved by the Invention

[0015] In recent years, there have been strong demands for high output, high capacity, and long life for non-aqueous secondary batteries. For the adhesives used in non-aqueous secondary batteries, it is required to improve the cycle characteristics of non-aqueous secondary batteries having electrodes using such adhesives.

[0016] The present invention has been made in view of the above circumstances, and an object thereof is to provide composite particles that can be used as a material for an adhesive, and a method for manufacturing the composite particles, and the material for the adhesive can form an electrode of a non-aqueous secondary battery having excellent cycle characteristics.

[0017] In addition, an object of the present invention is to provide a non-aqueous secondary battery adhesive composition, a non-aqueous secondary battery electrode paste, a non-aqueous secondary battery electrode capable of obtaining a non-aqueous secondary battery having excellent cycle characteristics, and a non-aqueous secondary battery including the non-aqueous secondary battery electrode, which contain the composite particles of the present invention and can form an electrode of a non-aqueous secondary battery having excellent cycle characteristics.

[0018] Means for Solving the Problems

[0019] The present invention includes the following aspects.

[0020] [1] A composite particle that is a composite particle containing a copolymer and a polyrotaxane,

[0021] The above copolymer has a first structural unit derived from monomer (a1) and a second structural unit derived from monomer (a2).

[0022] The above monomer (a1) is a non-ionic compound having only one ethylenic unsaturated bond.

[0023] The above monomer (a2) is a compound having a carboxyl group and only one ethylenic unsaturated bond.

[0024] The above polyrotaxane has a cyclic molecule having a cyclic skeleton and a linear molecule passing through the opening of the cyclic molecule and having blocking groups at both ends, and does not contain an ethylenic unsaturated bond.

[0025] [2] The composite particle according to [1], at least a part of the above polyrotaxane exists in the particle-like structure formed by the linear molecules of the above copolymer.

[0026] [3] The composite particle according to [1] or [2], at least one of the cyclic skeletons in the above cyclic molecule is a crown ether skeleton, a cyclic siloxane skeleton or a cyclic oligosaccharide skeleton.

[0027] [4] The composite particle according to any one of [1] to [3], at least one of the cyclic skeletons in the above cyclic molecule is an α-cyclodextrin skeleton.

[0028] [5] The composite particle according to any one of [1] to [4], at least one of the above blocking groups is a dinitrophenyl group, an adamantyl group, a trityl group or a derivative group of any of these groups.

[0029] [6] The composite particle according to any one of [1] to [5], at least one of the above blocking groups is an adamantyl group.

[0030] [7] The composite particle according to any one of [1] to [6], the above linear molecule is at least one selected from polyethylene glycol, polypropylene glycol, polyisoprene, polyisobutene, polybutadiene, polytetrahydrofuran, polyacrylate, polydimethylsiloxane, polyethylene, polypropylene.

[0031] [8] The composite particle according to any one of [1] to [7], at least one of the above linear molecules is polyethylene glycol.

[0032] [9] The composite particle according to any one of [1] to [8], the weight average molecular weight of the above linear molecule is 5,000 to 50,000.

[0033]

[10] The composite particle according to any one of [1] to [9], the content of the above polyrotaxane relative to 100 parts by mass of the above copolymer is 0.10 part by mass or more and 50 parts by mass or less.

[0034]

[11] For the composite particles according to any one of [1] to

[10] , the content ratio of the second structural unit in all the structural units of the copolymer is 0.10% by mass or more and 20% by mass or less.

[0035]

[12] For the composite particles according to any one of [1] to

[11] , the copolymer has a third structural unit derived from monomer (a3),

[0036] The monomer (a3) is a compound having a plurality of independent ethylenically unsaturated bonds.

[0037]

[13] For the composite particles according to

[12] , the content ratio of the third structural unit in all the structural units of the copolymer is 0.010% by mass or more and 10% by mass or less.

[0038]

[14] For the composite particles according to any one of [1] to

[13] , it is used as an adhesive for non-aqueous secondary batteries.

[0039]

[15] An adhesive composition for non-aqueous secondary batteries, which comprises the composite particles according to any one of [1] to

[14] and an aqueous medium.

[0040]

[16] For the adhesive composition for non-aqueous secondary batteries according to

[15] , the average particle diameter d50 of the composite particles is 0.18 μm or more and 1.0 μm or less.

[0041]

[17] A slurry for non-aqueous secondary battery electrodes, which comprises the composite particles according to any one of [1] to

[14] , an electrode active material, and an aqueous medium.

[0042]

[18] A non-aqueous secondary battery electrode, which comprises the composite particles according to any one of [1] to

[14] .

[0043]

[19] A non-aqueous secondary battery, which includes the non-aqueous secondary battery electrode according to

[18] .

[0044]

[20] A method for manufacturing composite particles, which includes the following steps: a polymerization step of carrying out emulsion polymerization of a raw material monomer (a) containing monomer (a1) and monomer (a2) in the presence of a polyrotaxane,

[0045] The monomer (a1) is a nonionic compound having only one ethylenically unsaturated bond,

[0046] The monomer (a2) is a compound having a carboxyl group and only one ethylenically unsaturated bond,

[0047] The above-mentioned rotaxane includes a cyclic molecule having a cyclic skeleton and a linear molecule that penetrates an opening of the cyclic molecule and has blocking groups at both ends, and does not have an ethylenic unsaturated bond.

[0048] Effects of the Invention

[0049] According to the present invention, composite particles that can be used as a binder material and a method for manufacturing the same can be provided, and the binder material can form an electrode of a non-aqueous secondary battery having excellent cycle characteristics.

[0050] Furthermore, according to the present invention, a non-aqueous secondary battery binder composition that can form an electrode of a non-aqueous secondary battery having excellent cycle characteristics and a slurry for a non-aqueous secondary battery electrode can be provided.

[0051] In addition, according to the present invention, a non-aqueous secondary battery electrode that can obtain a non-aqueous secondary battery having excellent cycle characteristics and a non-aqueous secondary battery having excellent cycle characteristics including the non-aqueous secondary battery electrode can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic cross-sectional view for explaining the function of the binder formed from the non-aqueous secondary battery binder composition of the present invention in the non-aqueous secondary battery electrode of the present invention.

[0053] Figure 2 It is a schematic diagram for explaining the rotaxane used as a raw material of the composite particles of the present invention.

[0054] Figure 3 It is a schematic diagram for explaining the state of a non-aqueous secondary battery binder composition including the composite particles of the present embodiment and an aqueous medium.

[0055] Figure 4 It is a schematic diagram for explaining the state of a non-aqueous secondary battery binder composition including other composite particles of the present embodiment and an aqueous medium.

[0056] Figure 5 It is a schematic diagram for explaining the state of a composition including copolymer particles, rotaxane, and an aqueous medium. DETAILED DESCRIPTION

[0057] In order to solve the above problems, the present inventors conducted in-depth research as follows to realize a binder for a non-aqueous secondary battery electrode that can form a non-aqueous secondary battery having excellent cycle characteristics.

[0058] Figure 1Schematic cross-sectional view for explaining the function of the binder formed from the binder composition for non-aqueous secondary batteries of the present invention in the electrodes of non-aqueous secondary batteries of the present invention.

[0059] Figure 1 The non-aqueous secondary battery electrode shown (hereinafter sometimes referred to as "electrode".) 20 includes a current collector 23 made of a copper foil or the like and an electrode active material layer 24 formed on the current collector 23. As one embodiment, the electrode active material layer 24 includes an electrode active material 22, a thickener 21, and a binder 25.

[0060] If, with the use of the non-aqueous secondary battery, that is, with the expansion and contraction of the electrode active material 22 accompanying charge and discharge, the electrode active material layer 24 of the electrode 20 expands and contracts and peels off from the current collector 23, the discharge capacity of the non-aqueous secondary battery equipped with the electrode 20 decreases. Further, even if the electrode active material layer 24 does not peel off from the current collector 23, if the adhesiveness between the electrode active materials 22 and between the electrode active material 22 and the current collector 23 becomes insufficient with the expansion and contraction of the electrode active material 22 and the like, the discharge capacity of the non-aqueous secondary battery also decreases.

[0061] Therefore, as the binder 25, a material is preferably used that can form a binder that can maintain the adhesiveness between the electrode active materials 22 and between the electrode active material 22 and the current collector 23 for a long time, and the electrode active material layer 24 is not easily peeled off from the current collector 23 in the electrode 20.

[0062] However, in the prior art, since the toughness of the binder 25 is insufficient, the binder 25 cannot follow the expansion and contraction of the electrode active material 22 accompanying charge and discharge.

[0063] The directions of expansion and contraction of the plurality of electrode active materials 22 included in the electrode active material layer 24 are random. Therefore, most of the binder 25 included in the electrode active material layer 24 is disposed between the electrode active materials 22 that expand and contract in different directions and between the electrode active material 22 that expands and contracts in different directions and the current collector 23. Therefore, if the binder 25 does not have sufficient followability for each of the plurality of materials that expand and contract in different directions and are joined via the binder 25, good adhesiveness cannot be obtained.

[0064] In contrast, for example, when a coating film containing an adhesive and not containing the electrode active material 22 is formed on a substrate, the adhesive in the coating film only needs to be able to follow only along the expansion and contraction direction of the substrate. Therefore, even an adhesive that can be used as a material for a coating film that is not easily peeled off from the substrate does not necessarily have the followability to sufficiently obtain the adhesiveness between the electrode active materials 22 and between the electrode active material 22 and the current collector 23, and the electrode active material layer 24 containing the adhesive and the electrode active material 22 is not necessarily not easily peeled off from the current collector 23.

[0065] Therefore, in the prior art, it is difficult to achieve good adhesiveness between the electrode active materials 22 and between the electrode active material 22 and the current collector 23, and an adhesive 25 in which the electrode active material layer 24 is not easily peeled off from the current collector 23.

[0066] Therefore, the present inventors focused on an adhesive containing a polymer obtained by copolymerizing a monomer (a1) composed of a nonionic compound having only one ethylenically unsaturated bond and a monomer (a2) composed of a compound having a carboxyl group and only one ethylenically unsaturated bond as a polymer that can easily obtain an electrode active material layer 24 that is not easily peeled off from a current collector 23 made of a copper foil or the like, and conducted in-depth research.

[0067] As a result, it was found that as long as composite particles (P) are used as an adhesive for a non-aqueous secondary battery, the above composite particles (P) contain a copolymer and a polyrotaxane, and the copolymer has a first structural unit derived from the monomer (a1) as a nonionic compound having only one ethylenically unsaturated bond and a second structural unit derived from the monomer (a2) as a compound having a carboxyl group and only one ethylenically unsaturated bond.

[0068] Figure 2 It is a schematic diagram for explaining the polyrotaxane used as a raw material of the composite particles of the present invention.

[0069] Figure 2 The polyrotaxane 2 shown includes a cyclic molecule 51 having a cyclic skeleton and a chain-like molecule 53 that penetrates the opening 55 of the cyclic molecule 51 and has blocking groups 52 at both ends. The polyrotaxane 2 does not contain an ethylenically unsaturated bond. In Figure 2 The symbol 54 represents a modifying group. The polyrotaxane 2 may not have the modifying group 54.

[0070] The composite particles (P) of the present embodiment can be in Figure 2In the presence of the polyrotaxane 2 shown, a raw material monomer (a) containing monomers (a1) and (a2) is copolymerized for production. For the composite particles (P) of the present embodiment, the cyclic molecules 51 contained in the polyrotaxane 2 can be movable relative to the linear molecule 53. Therefore, if stress is applied to the composite particles (P), the cyclic molecules 51 of the polyrotaxane 2 in the composite particles (P) can be movable relative to the linear molecule 53 (pulley effect), and the stress is dispersed. Further, in the composite particles (P) of the present embodiment, when stress is applied to the composite particles (P), the cyclic molecules 51 are movable, and if the distance between the cyclic molecules 51 on the linear molecule 53 approaches each other, an air spring effect of wanting to maintain the distance between the cyclic molecules 51 on the linear molecule 53 is exhibited, and thus restoration is performed.

[0071] Therefore, the adhesive formed of the composite particles (P) of the present embodiment has followability due to the polyrotaxane 2 with respect to the expansion and contraction of the electrode active material 22 accompanying the use of the non-aqueous secondary battery. As a result, it is presumed that the electrode active material layer 24 containing the adhesive 25 formed of the above composite particles (P) can obtain the functions of <1> and <2> shown below.

[0072] <1> Due to the followability due to the polyrotaxane 2, the holding force of the electrode active material 22 brought by the adhesive 25 present between the electrode active materials 22 in the electrode active material layer 24 and between the electrode active material 22 and the current collector 23 is increased, and even if the electrode active material 22 expands and contracts, the adhesiveness between the electrode active materials 22 and between the electrode active material 22 and the current collector 23 is maintained for a long time.

[0073] <2> Even if the electrode active material layer 24 expands and contracts due to the expansion and contraction of the electrode active material 22 or the like, due to the followability due to the polyrotaxane 2, the adhesiveness to the current collector 23 due to the structural units derived from the monomers (a1) and (a2) in the copolymer is effectively exhibited, and the electrode active material layer 24 is not easily peeled off from the current collector 23.

[0074] Furthermore, when the electrode 20 is formed using the above adhesive for a non-aqueous secondary battery, the adhesive 25 present between the electrode active materials 22 and between the electrode active material 22 and the current collector 23 contains the composite particles (P). Therefore, the synergistic effect brought by the copolymer and the polyrotaxane 2 contained in the composite particles (P) is sufficiently exhibited, and the electrode 20 having better adhesiveness between the electrode active materials 22 and between the electrode active material 22 and the current collector 23 is obtained. As a result, it is presumed that a non-aqueous secondary battery and a non-aqueous secondary battery electrode having excellent cycle characteristics can be obtained.

[0075] Here, an example of an adhesive composition for a non-aqueous secondary battery containing the composite particles (P) of the present embodiment and an aqueous medium will be described with reference to the accompanying drawings.

[0076] Figure 3 It is a schematic diagram for explaining the state of the adhesive composition for a non-aqueous secondary battery containing the composite particles of the present embodiment and an aqueous medium. Figure 3 The composite particles 10 shown are manufactured by the manufacturing method of the present embodiment using a polymerization step in which a raw material monomer (a) containing a monomer (a1) and a monomer (a2) is copolymerized in the presence of the polyrotaxane 2 shown in Figure 2 As shown in Figure 3 The composite particles 10 contain a copolymer 1 and Figure 2 the polyrotaxane 2 shown, and are dispersed in an aqueous medium.

[0077] As one form speculated by the inventors, as shown in Figure 3 Shown in Figure 3 The copolymer 1 contained in the composite particles 10 shown has a particulate structure (block structure) 3 formed by a random coil-shaped polymer chain, that is, a chain-like molecule. As one form speculated by the inventors, the polyrotaxane 2 has a particulate shape and is integrated with the particulate structure 3 formed by the chain-like molecules. More specifically, as shown in Figure 3 Shown in

[0078] As shown in Figure 3 Shown in

[0079] As one form, Figure 3The binder composition for non-aqueous secondary batteries containing composite particles 10 and an aqueous medium shown is a soap-free emulsion without a surfactant, and the composite particles 10 are dispersed in the aqueous medium. The binder composition for non-aqueous secondary batteries containing composite particles 10 without a surfactant can be manufactured, for example, by a soap-free emulsion polymerization method that does not use a surfactant when manufacturing the composite particles 10. As the soap-free emulsion polymerization method, specifically, a method can be used in which a monomer having a functional group such as a carboxyl group and / or a polymerizable surfactant having radical polymerizability is used as the raw material monomer (a) containing monomer (a1) and monomer (a2), etc.

[0080] The composite particles (P) of the present embodiment only need to contain copolymer 1 and polyrotaxane 2, and as shown in Figure 3 they can be composite particles 10 without a surfactant 4, or as shown in Figure 4 they can be composite particles 11 with a surfactant.

[0081] Figure 4 It is a schematic diagram for explaining the state of the binder composition for non-aqueous secondary batteries containing other composite particles and an aqueous medium of the present embodiment.

[0082] Figure 4 The composite particles 11 shown are emulsion particles (dispersed particles) containing copolymer 1, polyrotaxane 2, and surfactant 4. Specifically, Figure 4 the composite particles 11 shown have a surfactant 4 in which a hydrophilic group is bonded to the outside of the formed particle-like structure 3 in the copolymer 1. The surfactant 4 does not correspond to the raw material monomer (a) containing a polymerizable surfactant used when manufacturing the composite particles 11, and is derived from a non-polymerizable surfactant (c).

[0083] When using the binder composition for non-aqueous secondary batteries containing the composite particles 10 shown in Figure 3 and / or Figure 4 the composite particles 11 shown and an aqueous medium to form the electrode 20 shown in Figure 1 the binder 25 present between the electrode active materials 22 and between the electrode active material 22 and the current collector 23 contains the composite particles 10 and / or the composite particles 11. Therefore, the synergistic effect brought by the copolymer 1 and the polyrotaxane 2 contained in the composite particles 10 and / or the composite particles 11 is fully exerted, and the electrode 20 with good adhesiveness between the electrode active materials 22 and between the electrode active material 22 and the current collector 23 is obtained. Figure 2 shown is obtained.

[0084] In contrast, for example, when using a composition in which a copolymer produced by operating in the same manner as the composite particle 11 shown in Figure 4 except for copolymerizing the raw material monomer (a) in the absence of the polyrotaxane 2 and the polyrotaxane 2 are dispersed in an aqueous medium in the presence of the surfactant 4 to form an electrode, as shown below, the adhesiveness between the electrode active materials and between the electrode active material and the current collector cannot be sufficiently obtained. Figure 4 When forming an electrode using a composition in which a copolymer produced by operating in the same manner as the composite particle 11 shown in Figure 4 except for copolymerizing the raw material monomer (a) in the absence of the polyrotaxane 2 and the polyrotaxane 2 are dispersed in an aqueous medium in the presence of the surfactant 4, as shown below, the adhesiveness between the electrode active materials and between the electrode active material and the current collector cannot be sufficiently obtained.

[0085] Figure 5 For explaining the state of a composition containing copolymer particles 40 composed of a copolymer 1 produced by operating in the same manner as the composite particle 11 shown in Figure 4 except for copolymerizing the raw material monomer (a) without using the polyrotaxane 2, the polyrotaxane 2, and an aqueous medium. Figure 4 A schematic diagram showing the state of a composition containing copolymer particles 40 composed of a copolymer 1 produced by operating in the same manner as the composite particle 11 shown in Figure 4 except for copolymerizing the raw material monomer (a) without using the polyrotaxane 2, the polyrotaxane 2, and an aqueous medium. Figure 5 The copolymer particles 40 shown in Figure 5 are emulsion particles containing the copolymer 1 and the surfactant 4. Figure 5 The polyrotaxane 2 shown in Figure 5 becomes an emulsion particle by binding the surfactant 42. In Figure 5 , the polyrotaxane 2 that becomes an emulsion particle by binding the surfactant 42 is taken as an example for explanation, but the polyrotaxane 2 may also be a substance that does not bind the surfactant 42. For example, it may be a substance that is dispersed in an aqueous medium by having a hydrophilic group. Figure 5 In Figure 5 , the polyrotaxane 2 that becomes an emulsion particle by binding the surfactant 42 is taken as an example for explanation, but the polyrotaxane 2 may also be a substance that does not bind the surfactant 42. For example, it may be a substance that is dispersed in an aqueous medium by having a hydrophilic group.

[0086] In Figure 5 In the composition shown in Figure 5 , the copolymer particles 40 containing the copolymer 1 exist separately from the polyrotaxane 2 in the aqueous medium. This is because the copolymer particles 40 that become emulsion particles and the polyrotaxane 2 that become emulsion particles are electrically repulsive from each other, so the dispersion of each of the copolymer particles 40 and the polyrotaxane 2 is maintained. Therefore, when forming an electrode using the composition shown in Figure 5 , between the electrode active materials of the formed electrode and between the electrode active material and the current collector, the copolymer 1 forming the copolymer particles 40 and the polyrotaxane 2 are likely to be arranged in a separated state. As a result, the synergistic effect brought by the copolymer 1 and the polyrotaxane 2 cannot be sufficiently obtained, and an electrode with insufficient adhesiveness between the electrode active materials and between the electrode active material and the current collector is formed. Figure 5 In the composition shown in Figure 5 , the copolymer particles 40 containing the copolymer 1 exist separately from the polyrotaxane 2 in the aqueous medium. This is because the copolymer particles 40 that become emulsion particles and the polyrotaxane 2 that become emulsion particles are electrically repulsive from each other, so the dispersion of each of the copolymer particles 40 and the polyrotaxane 2 is maintained. Therefore, when forming an electrode using the composition shown in Figure 5 , between the electrode active materials of the formed electrode and between the electrode active material and the current collector, the copolymer 1 forming the copolymer particles 40 and the polyrotaxane 2 are likely to be arranged in a separated state. As a result, the synergistic effect brought by the copolymer 1 and the polyrotaxane 2 cannot be sufficiently obtained, and an electrode with insufficient adhesiveness between the electrode active materials and between the electrode active material and the current collector is formed.

[0087] Moreover, Figure 5 The composition shown in Figure 5 contains, in addition to the surfactant 4 used in manufacturing the copolymer particles 40, a surfactant 42 for dispersing the polyrotaxane 2 in the aqueous medium. In this case, for example, compared with the composition containing the composite particle 10 shown in Figure 3 or Figure 3 shown in Figure 3 or Figure 4Compared with the composition of the composite particles 11 shown, the content of the surfactant contained in the composition becomes larger, and the possibility of the surfactant remaining as an impurity in the electrode is further increased. As a result, it has an adverse effect on the cycle characteristics of the battery equipped with the electrode and may cause a decrease in the cycle characteristics of the battery.

[0088] Based on these circumstances, when an electrode is formed using Figure 5 the composition shown, a non-aqueous secondary battery with excellent cycle characteristics cannot be obtained.

[0089] Furthermore, the inventors of the present invention manufactured an electrode using the above composite particles (P) as a binder for a non-aqueous secondary battery, and confirmed that the non-aqueous secondary battery having this electrode has excellent cycle characteristics, and thus the present invention was conceived.

[0090] Hereinafter, the composite particles of the present invention, the binder composition for a non-aqueous secondary battery, the paste for a non-aqueous secondary battery electrode, the non-aqueous secondary battery electrode, the non-aqueous secondary battery, and the method for manufacturing the composite particles will be described in detail. It should be noted that the present invention is not limited to the embodiments shown below.

[0091] Here, the following terms used in this specification will be described.

[0092] The so-called “(meth)acrylic acid” is a general term for acrylic acid and methacrylic acid. The so-called “(meth)acrylate” is a general term for acrylate and methacrylate.

[0093] The so-called “ethylenically unsaturated bond” means an ethylenically unsaturated bond having radical polymerizability unless otherwise specified.

[0094] In a polymer using a compound having an ethylenically unsaturated bond, the above-mentioned structural unit derived from the compound having an ethylenically unsaturated bond means a structural unit having the same chemical structure as the part other than the ethylenically unsaturated bond in the above-mentioned compound having an ethylenically unsaturated bond and the part other than the part corresponding to the ethylenically unsaturated bond in the above-mentioned structural unit in the above-mentioned polymer. The ethylenically unsaturated bond of the above-mentioned compound changes to a single bond when forming a polymer. For example, in a polymer of methyl methacrylate, the structural unit derived from methyl methacrylate is represented by -CH2-C(CH3)(COOCH3)-.

[0095] It should be noted that in the case of a polymer of a compound having an ionic functional group and an ethylenic unsaturated bond, for example, with respect to a structural unit having an ionic functional group such as a carboxyl group as in the second structural unit described later, whether a part of the above functional group is ion-exchanged or not ion-exchanged, it becomes a structural unit derived from the same ionic compound. For example, a structural unit represented by -CH2-C(CH3)(COONa)- can also be considered as a structural unit derived from methacrylic acid.

[0096] In addition, with respect to a compound having a plurality of independent ethylenic unsaturated bonds, as a structural unit of a polymer of the above compound, one or more ethylenic unsaturated bonds can remain inside the structural unit. For example, in the case of a polymer of divinylbenzene, the structural unit derived from divinylbenzene can be a structure without an ethylenic unsaturated bond (both parts corresponding to the two ethylenic unsaturated bonds of divinylbenzene are introduced into the form of the polymer chain), or can be a structure having one ethylenic unsaturated bond (only the part corresponding to one ethylenic unsaturated bond is introduced into the form of the polymer chain). Here, the so-called plurality of independent ethylenic unsaturated bonds means a plurality of ethylenic unsaturated bonds that do not form a conjugated diene with each other.

[0097] Furthermore, after polymerization, when a part other than the chain-like structure corresponding to the ethylenic unsaturated bond in the polymer, such as a functional group such as a carboxyl group, no longer corresponds to the chemical structure of the monomer through a chemical reaction, the structural unit of the polymer is set as the structural unit in the polymer derived from the compound having an ethylenic unsaturated bond. For example, in the case where vinyl acetate is polymerized and then saponified, considering the chemical structure of the polymer as a reference, the structural unit of the polymer is set as a structural unit not derived from vinyl acetate but from vinyl alcohol.

[0098] In the present embodiment, the so-called "class" attached to the compound name means a group of compounds including the compound structure, and also includes the compound having a substituent.

[0099] <1. Composite particle (P)>

[0100] As one form, the composite particle (P) of the present embodiment is used as an adhesive for a non-aqueous secondary battery. The composite particle (P) of the present embodiment contains a copolymer and Figure 2 the polyrotaxane 2 shown. It is presumed that the chain-like molecules of the copolymer contained in the composite particle (P) of the present embodiment form a particle-like structure.

[0101] The molecules of the polyrotaxane 2 can be present either on the surface or inside the particulate structure composed of the copolymer. Preferably, at least a part of the polyrotaxane 2 is present inside the particulate structure formed by the chain molecules of the copolymer. The reason is that, for example, compared with the case where all of the polyrotaxane 2 contained in the composite particles (P) adheres to the outside of the particulate structure, the interaction between the polyrotaxane 2 and the chain molecules is promoted, and the synergistic effect between the copolymer and the polyrotaxane 2 is more easily exerted. As a result, the composite particles (P) can form an electrode 20 in which the adhesiveness between the electrode active materials 22 and between the electrode active material 22 and the current collector 23 is better.

[0102] (Copolymer)

[0103] The copolymer contained in the composite particles (P) of the present embodiment has at least a first structural unit derived from the following monomer (a1) and a second structural unit derived from the following monomer (a2).

[0104] In addition to the first structural unit and the second structural unit, the copolymer contained in the composite particles (P) of the present embodiment may further contain a third structural unit derived from a monomer (a3) composed of a compound having a plurality of independent ethylenic unsaturated bonds that is not equivalent to the monomer (a1) or the monomer (a2), and / or a fourth structural unit derived from another monomer (a4) that is not equivalent to all of the monomers (a1) to (a3).

[0105] [First structural unit]

[0106] The first structural unit in the copolymer contained in the composite particles (P) of the present embodiment is derived from the monomer (a1).

[0107] The monomer (a1) is a nonionic compound having only one ethylenic unsaturated bond. That is, the monomer (a1) is a compound that does not have either an anionic functional group or a cationic functional group. However, silane compounds are not included in the monomer (a1). The monomer (a1) may be only one compound or a combination of two or more compounds.

[0108] As the monomer (a1), at least one of (meth)acrylate and an aromatic compound having an ethylenic unsaturated bond is preferably used, and a combination of two compounds is more preferably used. The (meth)acrylate is more preferably an alkyl (meth)acrylate. The number of carbon atoms of the alkyl group in the alkyl (meth)acrylate is preferably 1 to 20. In this case, monomers (a1) other than the alkyl (meth)acrylate and the aromatic compound having an ethylenic unsaturated bond described later can be used in combination.

[0109] Examples of the alkyl (meth)acrylate contained in the (meth)acrylate used as the monomer (a1) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc. Among them, 2-ethylhexyl acrylate is preferably included in order to form the composite particles (P) capable of forming an electrode active material layer having excellent electrolyte resistance.

[0110] Examples of the aromatic compound having an ethylenic unsaturated bond used as the monomer (a1) include styrene, tert-butylstyrene, α-methylstyrene, p-methylstyrene, 1,1-diphenylethylene, etc. When the monomer (a1) contains an aromatic vinyl compound, it is more preferably to contain at least one of styrene and α-methylstyrene. In order to have excellent dispersibility in an aqueous medium, a non-aqueous secondary battery having an electrode including a binder for non-aqueous secondary battery containing the composite particles (P) has more excellent cycle characteristics, and styrene is further preferably included.

[0111] Examples of the monomer (a1) other than the (meth)acrylate and the aromatic compound having an ethylenic unsaturated bond include a compound having an ethylenic unsaturated bond and a nonionic polar functional group, an aliphatic hydrocarbon compound having an ethylenic unsaturated bond, an alicyclic hydrocarbon compound having an ethylenic unsaturated bond, etc.

[0112] The polar functional group in the compound having an ethylenic unsaturated bond and a polar functional group used as the monomer (a1) preferably contains at least one of a hydroxyl group and a cyano group, and more preferably contains a hydroxyl group.

[0113] Examples of the compound having an ethylenic unsaturated bond and a polar functional group used as the monomer (a1) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, (meth)acrylonitrile, etc. In order to obtain good polymerization stability when manufacturing the composite particles (P), 2-hydroxyethyl methacrylate is preferably included.

[0114] [Second structural unit]

[0115] The second structural unit in the copolymer contained in the composite particles (P) of the present embodiment is derived from the monomer (a2).

[0116] The monomer (a2) is a compound having only one ethylenic unsaturated bond and a carboxyl group. The monomer (a2) may be only one compound or a combination of two or more compounds.

[0117] As the monomer (a2), a compound having a plurality of carboxyl groups in one molecule can be used. That is, the copolymer may contain a plurality of carboxyl groups in one structural unit.

[0118] Examples of the monomer (a2) having a carboxyl group include unsaturated monocarboxylic acids such as methacrylic acid, acrylic acid, and crotonic acid; unsaturated dicarboxylic acids such as itaconic acid and fumaric acid. Among them, in order to form the composite particles (P) of the electrode 20 having good adhesiveness between the electrode active materials 22 and between the electrode active material 22 and the current collector 23, the monomer (a2) is preferably at least one of acrylic acid, methacrylic acid, and itaconic acid.

[0119] At least a part of the structural unit derived from the monomer (a2) may also form a salt with a basic substance. Examples of the monomer (a2) forming a salt include, for example, metal salts and ammonium salts of the monomer (a2). Examples of the metal of the metal salt include alkali metals such as lithium, sodium, and potassium. Specific compounds include lithium (meth)acrylate, lithium itaconate, dilithium itaconate, sodium (meth)acrylate, sodium itaconate, disodium itaconate, ammonium (meth)acrylate, ammonium itaconate, and diammonium itaconate.

[0120] [Third structural unit]

[0121] The copolymer contained in the composite particles (P) of the present embodiment may have a third structural unit as an optional structural unit. The third structural unit is derived from the monomer (a3). The monomer (a3) is a compound having a plurality of independent ethylenically unsaturated bonds. The so-called "independent" means not the conjugated double bonds such as those possessed by 1,3-butadiene. Therefore, the monomer (a3) is a compound capable of forming a crosslinked structure in the radical polymerization with the monomers (a1) and (a2). The monomer (a3) does not correspond to either of the monomers (a1) and (a2). As the monomer (a3), only one compound may be used, or two or more different compounds may be used.

[0122] Examples of the monomer (a3) include compounds having 2 ethylenically unsaturated bonds such as divinylbenzene, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 2-hydroxy-3-acryloyloxypropyl methacrylate; compounds having 3 or more ethylenically unsaturated bonds such as trimethylolpropane tri(meth)acrylate. In order to obtain good polymerization stability in the production of the composite particles (P), and for the non-aqueous secondary battery having the electrode 20 including the binder for non-aqueous secondary battery containing the composite particles (P) to have a lower internal resistance and excellent cycle characteristics, the monomer (a3) is preferably at least one of divinylbenzene and trimethylolpropane triacrylate.

[0123] [Other monomer (a4)]

[0124] The other monomer (a4) is a monomer that does not correspond to any of the monomers (a1) to (a3). Examples of the other monomer (a4) include compounds having only one ethylenically unsaturated bond and having an anionic functional group other than a carboxyl group such as a sulfo group or a phosphoric acid group, surfactants having an ethylenically unsaturated bond (hereinafter sometimes referred to as "polymerizable surfactants"), compounds having an ethylenically unsaturated bond and having a function as a silane coupling agent, etc., but are not limited to them.

[0125] Examples of the compound having only one ethylenically unsaturated bond and having a sulfo group include aromatic vinyl compounds having a sulfo group, aromatic vinyl compounds having a sulfo group formed into a salt, etc. Among them, at least one of styrenesulfonic acid and styrenesulfonates is preferably used, and styrenesulfonates are more preferably used. In order to obtain good polymerization stability in the production of the composite particles (P), sodium styrenesulfonate is further preferably used.

[0126] As an example of the polymerizable surfactant as the other monomer (a4), a compound having an ethylenically unsaturated bond and having a function as a surfactant can be used.

[0127] Examples of the polymerizable surfactant include, for example, compounds represented by the following chemical formulas (1) to (4).

[0128]

[0129] In formula (1), R 1 is an alkyl group. p is an integer of 10 to 40. R 1 is preferably an alkyl group having 10 to 40 carbon atoms, more preferably a straight-chain unsubstituted alkyl group having 10 to 40 carbon atoms.

[0130]

[0131] In formula (2), R 2 is an alkyl group. q is an integer of 10 to 12. R 2 is preferably an alkyl group having 10 to 40 carbon atoms, more preferably a straight-chain unsubstituted alkyl group having 10 to 40 carbon atoms. Examples of the compound represented by formula (2) include, for example, polyoxyethylene alkyl ether sulfate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Aqualon KH-10), etc.

[0132]

[0133] In formula (3), R 3 is an alkyl group. M 1 is NH4 or Na. R 3Preferably an alkyl group having 10 to 40 carbon atoms, more preferably a straight-chain unsubstituted alkyl group having 10 to 40 carbon atoms.

[0134]

[0135] In formula (4), R 4 is an alkyl group. M 2 is NH4 or Na. R 4 Preferably an alkyl group having 10 to 40 carbon atoms, more preferably a straight-chain unsubstituted alkyl group having 10 to 40 carbon atoms.

[0136] As an example of the other monomer (a4), a compound having an ethylenically unsaturated bond and having a function as a silane coupling agent, examples thereof include vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltriethoxysilane and the like.

[0137] [Content ratio of each structural unit in the copolymer]

[0138] The content ratio of each structural unit in the copolymer contained in the composite particles (P) of the present embodiment is regarded as the same as the content ratio of each monomer in the total amount of the monomer components used in the production of the composite particles (P).

[0139] (Content ratio of the first structural unit in all structural units)

[0140] The content ratio of the first structural unit in all structural units of the copolymer (in other words, the content ratio of the monomer (a1) in the total amount of the monomer components used in the production of the composite particles (P)) is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 75% by mass or more, and particularly preferably 80% by mass or more. The reason is that better polymerization stability can be obtained when producing the composite particles (P). The content ratio of the first structural unit in all structural units is preferably 97% by mass or less, more preferably 95% by mass or less, still more preferably 94% by mass or less. The reason is that the composite particles (P) can form an electrode 20 with good adhesion between the electrode active materials 22 and between the electrode active material 22 and the current collector 23.

[0141] Regarding the composition of the monomer (a1), in order to adjust the glass transition temperature of the composite particles (P) or to adjust the polymerization rate corresponding to the molecular design, it is preferable to appropriately adjust the type and amount of the compound.

[0142] Specifically, when the monomer (a1) contains an aromatic compound having an ethylenically unsaturated bond, the content ratio of the structural unit derived from the aromatic compound having an ethylenically unsaturated bond in all the structural units is preferably 36% by mass or more, more preferably 41% by mass or more, and still more preferably 43% by mass or more. The reason is that in the case of manufacturing the non-aqueous secondary battery binder composition containing the composite particles (P), composite particles (P) with excellent dispersibility are obtained.

[0143] (Content ratio of the second structural unit in all the structural units)

[0144] The content ratio of the second structural unit in all the structural units of the copolymer (in other words, the content ratio of the monomer (a2) in the total amount of the monomer components used for manufacturing the composite particles (P)) is preferably 0.10% by mass or more, more preferably 1.0% by mass or more, still more preferably 3.0% by mass, and particularly preferably 4.0% by mass or more. The reason is that composite particles (P) can form an electrode 20 with better adhesion between the electrode active materials 22 and between the electrode active material 22 and the current collector 23. The content ratio of the second structural unit in all the structural units is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less. The reason is that better polymerization stability is obtained when manufacturing the composite particles (P).

[0145] (Content ratio of the third structural unit in all the structural units)

[0146] When the copolymer contained in the composite particles (P) of the present embodiment contains a third structural unit, the content ratio of the third structural unit in all the structural units of the copolymer (in other words, the content ratio of the monomer (a3) in the total amount of the monomer components used for manufacturing the composite particles (P)) is preferably 0.010% by mass or more, more preferably 0.020% by mass or more, still more preferably 0.030% by mass or more. The reason is that the effect of the monomer (a3) as an internal crosslinking agent is significantly obtained, the deterioration of the copolymer is suppressed, and composite particles (P) can be used as a material for an adhesive of a non-aqueous secondary battery with more excellent cycle characteristics. The content ratio of the third structural unit in all the structural units of the copolymer is preferably 10% by mass or less, more preferably 5.0% by mass or less, still more preferably 1.0% by mass or less, and particularly preferably 0.1% by mass or less. The reason is that gelation of the copolymer can be suppressed.

[0147] (Content ratio of the fourth structural unit in all the structural units)

[0148] When the copolymer contained in the composite particle (P) of the present embodiment contains a fourth structural unit derived from another monomer (a4), and the other monomer (a4) is a compound having only one ethylenically unsaturated bond and a sulfo group, the content ratio of the fourth structural unit in all the structural units of the copolymer (in other words, the content ratio of the monomer (a4) in the total amount of the monomer components used for producing the composite particle (P)) is preferably 0.10% by mass or more, more preferably 0.20% by mass or more, and still more preferably 0.30% by mass or more. The reason is that good polymerization stability can be obtained when producing the composite particle (P). The content ratio of the fourth structural unit in all the structural units of the copolymer is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and still more preferably 1.0% by mass or less. The reason is that the particle diameter, viscosity, etc. of the composite particle (P) can be appropriately adjusted.

[0149] When the copolymer of the present embodiment contains a fourth structural unit derived from another monomer (a4), and the other monomer (a4) is a polymerizable surfactant, the content ratio of the fourth structural unit in all the structural units of the copolymer (in other words, the content ratio of the monomer (a4) in the total amount of the monomer components used for producing the composite particle (P)) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.08% by mass or more. The reason is that the effects brought about by the inclusion of the polymerizable surfactant become significant, and good polymerization stability can be obtained when producing the composite particle (P). The content ratio of the fourth structural unit in all the structural units of the copolymer is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and still more preferably 1.0% by mass or less, and particularly preferably 0.5% by mass. The reason is that the particle diameter, viscosity, etc. of the composite particle (P) can be appropriately adjusted.

[0150] (Polyrotaxane)

[0151] As Figure 2 shown, the polyrotaxane 2 of the present embodiment contained in the composite particle (P) of the present embodiment includes a cyclic molecule 51 having a cyclic skeleton and a linear molecule 53 passing through an opening 55 of the cyclic molecule 51. The linear molecule 53 has blocking groups 52 at both ends.

[0152] In addition, the polyrotaxane 2 does not have an ethylenically unsaturated bond. This is because the production of the composite particle (P) becomes easy.

[0153] The polyrotaxane 2 may be used alone only in one kind, or may be used in combination of two or more kinds.

[0154] As Figure 2As shown in the figure, the cyclic molecule 51 of the polyrotaxane 2 has an opening 55 through which the linear molecule 53 can pass through. The cyclic molecule 51 can move along the linear molecule 53 in a state where it is penetrated by the linear molecule 53. The number of cyclic molecules 51 in one molecule of the polyrotaxane 2 is not particularly limited. For example, it can be 1 to 500, it can be 5 to 300, and it can be 10 to 200. When the number of cyclic molecules 51 is plural, the cyclic molecules 51 of the polyrotaxane 2 can be only one kind, or two or more kinds. It can be as shown in Figure 2 the figure, a modifying group 54 is bonded to the cyclic skeleton of the cyclic molecule 51.

[0155] At least one of the cyclic skeletons of the cyclic molecule 51 is preferably a crown ether skeleton, a cyclic siloxane skeleton, or a cyclic oligosaccharide skeleton. Among them, the cyclic skeleton is more preferably a cyclic oligosaccharide skeleton. The reason is that by reacting the hydroxyl group of the cyclic skeleton with a specified compound having an epoxy group or the like, the modifying group 54 can be easily introduced into the cyclic skeleton. In the cyclic oligosaccharide skeleton, in order to more easily introduce the modifying group 54, an α-cyclodextrin skeleton is particularly preferred.

[0156] As the modifying group 54 bonded to the cyclic skeleton of the cyclic molecule 51, various organic groups without an ethylenic unsaturated bond can be cited. As the organic group, for example, a hydrocarbon group having 1 or more carbon atoms and having 1 or more substituents can be cited. Specifically, for example, acetyl group, butyl ester group, hexyl ester group, octadecyl ester group, hydroxyl group, amino group, amide group, carboxyl group, mercapto group, etc. can be cited.

[0157] The linear molecule 53 of the polyrotaxane 2 can be linear or branched.

[0158] The linear molecule 53 is preferably at least one selected from polyethylene glycol, polypropylene glycol, polyisoprene, polyisobutene, polybutadiene, polytetrahydrofuran, polyacrylate, polydimethylsiloxane, polyethylene, polypropylene, and polycaprolactone. In order to be a linear molecule 53 with good function of accommodating the cyclic molecule 51 of the polyrotaxane 2, polyethylene glycol is more preferred.

[0159] The weight-average molecular weight of the chain-like molecule 53 is preferably 5,000 to 50,000, more preferably 7,500 to 40,000. If the weight-average molecular weight of the chain-like molecule 53 is 5,000 or more, the length of the chain-like molecule 53 can be sufficiently ensured. Therefore, in the polymer (P) for an adhesive, the distance in which the cyclic molecule 51 can move relative to the chain-like molecule 53 can be sufficiently lengthened. As a result, the polymer (P) for an adhesive has better followability to the expansion and contraction of the electrode active material. If the weight-average molecular weight of the chain-like molecule 53 is 50,000 or less, the compatibility between the copolymer contained in the composite particles (P) and the polyrotaxane 2 becomes good, which is therefore preferable.

[0160] The stopper group 52 of the polyrotaxane 2 has a function of preventing the cyclic molecule 51 from detaching from the chain-like molecule 53 by its large volume and ionicity, etc. The stopper groups 52 disposed at both ends of the chain-like molecule 53 may be the same or different from each other.

[0161] As the stopper group 52 that prevents the cyclic molecule 51 from detaching from the chain-like molecule 53 by its large volume, a group having a ring structure can be cited. At least one of the stopper groups 52 is preferably a dinitrophenyl group, an adamantyl group, a trityl group or a derivative group of any of these groups, and in order to obtain a polyrotaxane 2 that can be easily manufactured, an adamantyl group (either 1-adamantyl group or 2-adamantyl group) is more preferable. The above stopper group 52 may further have one or two or more substituents. Examples of the substituents that the stopper group 52 can have include, for example, an alkyl group, an alkoxy group, a hydroxyl group, a halogen group, a cyano group, a sulfonyl group, a carboxyl group, an amino group, a phenyl group, etc.

[0162] The weight-average molecular weight of the polyrotaxane 2 is preferably 100,000 to 1,000,000, more preferably 150,000 to 900,000. If the weight-average molecular weight of the polyrotaxane 2 is 100,000 or more, the elasticity of the composite particles (P) becomes suitable, which is therefore preferable. If the weight-average molecular weight of the polyrotaxane 2 is 1,000,000 or less, the compatibility between the copolymer contained in the composite particles (P) and the polyrotaxane 2 becomes good, which is therefore preferable.

[0163] The polyrotaxane 2 can be manufactured by a known method.

[0164] As the polyrotaxane 2, commercially available products can be used. Examples of commercially available polyrotaxane 2 include, for example, "Cellm (registered trademark) super polymer SH2400P", "Cellm (registered trademark) super polymer SH1300P", "Cellm (registered trademark) super polymer SH3400P", etc., commercially available from Advanced Soft Materials Co., Ltd.

[0165] Among these commercially available polyrotaxanes 2, in order to form composite particles (P) of an electrode 20 with better adhesion between electrode active materials 22 and between the electrode active material 22 and the current collector 23, it is preferable to use a cyclic molecule 51 containing a cyclic skeleton composed of an α-cyclodextrin skeleton and a chain molecule 53 composed of polyethylene glycol with a weight average molecular weight of 20,000 having adamantyl groups as blocking groups 52 at both ends, and Selm (registered trademark) ultra-high polymer SH2400P with a weight average molecular weight of 400,000.

[0166] 〔Content of polyrotaxane 2 in composite particles (P)〕

[0167] The content of polyrotaxane 2 in the composite particles (P) of the present embodiment is regarded as the same as the mass of polyrotaxane 2 relative to the total mass of the monomer components used in the production of the composite particles (P).

[0168] The content of polyrotaxane 2 relative to 100 parts by mass of the copolymer is preferably 0.10 part by mass or more. The reason is that the effects brought by the inclusion of polyrotaxane 2 in the composite particles (P) become significant, and as a result, the composite particles (P) can form an electrode 20 with better adhesion between the electrode active materials 22 and between the electrode active material 22 and the current collector 23. Considering the above viewpoints, the content of polyrotaxane 2 is more preferably 0.50 part by mass or more, further preferably 0.80 part by mass or more, and particularly preferably 1.5 parts by mass or more. The content of polyrotaxane 2 can be 2.5 parts by mass and can be 5.0 parts by mass.

[0169] In addition, the content of polyrotaxane 2 relative to 100 parts by mass of the copolymer is preferably 50 parts by mass or less. The reason is that the content of the copolymer in the composite particles (P) can be sufficiently ensured, and the non-aqueous secondary battery having an electrode 20 containing a binder for non-aqueous secondary batteries containing the composite particles (P) has a lower internal resistance. Considering the above viewpoints, the content of polyrotaxane 2 is more preferably 30 parts by mass or less, further preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less.

[0170] If the above is summarized, the content of polyrotaxane 2 relative to 100 parts by mass of the copolymer is preferably 0.10 part by mass or more and 50 parts by mass or less, more preferably 0.50 part by mass or more and 30 parts by mass or less, further preferably 0.80 part by mass or more and 15 parts by mass or less, and particularly preferably 1.5 parts by mass or more and 10 parts by mass or less.

[0171] 〔Glass transition temperature (Tg) of composite particles (P)〕

[0172] The glass transition temperature (Tg) of the composite particles (P) of the present embodiment is the peak temperature of the DDSC chart obtained as the temperature differential of DSC by performing DSC measurement using a differential scanning calorimetry (DSC) apparatus (EXSTAR DSC / SS7020 manufactured by Hitachi High-Tech Science Corporation) at a heating rate of 10 °C / minute in a nitrogen atmosphere.

[0173] The glass transition temperature (Tg) of the composite particles (P) is preferably -30 °C or higher, more preferably -10 °C or higher. The reason is that a non-aqueous secondary battery having an electrode including a binder for non-aqueous secondary battery containing the composite particles (P) has excellent cycle characteristics.

[0174] The glass transition temperature (Tg) of the composite particles (P) is preferably 100 °C or lower, more preferably 50 °C or lower, and further preferably 40 °C or lower. The reason is that the film-forming property of the composite particles (P) is improved, and a non-aqueous secondary battery having an electrode including a binder for non-aqueous secondary battery containing the composite particles (P) has excellent cycle characteristics.

[0175] 〔Method for manufacturing composite particles (P)〕

[0176] The composite particles (P) of the present embodiment can be manufactured, for example, by the method shown below.

[0177] It can be manufactured by subjecting a raw material monomer containing monomer (a1) and monomer (a2), and optionally monomer (a3) composed of a compound having a plurality of independent ethylenically unsaturated bonds and / or other monomer (a4) to emulsion polymerization (polymerization step) in the presence of polyrotaxane 2. Hereinafter, the monomers ((a1) to (a4) components) used for synthesizing the composite particles (P) may be collectively referred to as raw material monomer (a).

[0178] As a method for subjecting the raw material monomer (a) to emulsion polymerization in the presence of polyrotaxane 2, for example, a method of subjecting the raw material monomer (a) to emulsion polymerization in an aqueous medium (b) containing polyrotaxane 2 can be cited. In the case of manufacturing the composite particles (P) by the emulsion polymerization method, in addition to polyrotaxane 2, raw material monomer (a), and aqueous medium (b), components such as a non-polymerizable surfactant (c), a basic substance (d), a radical polymerization initiator (e), and a chain transfer agent (f) can also be used.

[0179] In the present embodiment, an example was given in which the composite particles (P) were produced by emulsion polymerization of the raw material monomer (a) in the presence of the polyrotaxane 2, but the production method of the composite particles (P) is not limited to the above production method. For example, instead of the emulsion polymerization method, suspension polymerization, solution polymerization, bulk polymerization, etc. can be used to copolymerize the raw material monomer (a) in the presence of the polyrotaxane 2. In addition, when producing the composite particles (P), a continuous polymerization method or a batch polymerization method can be used.

[0180] 〔Aqueous medium (b)〕

[0181] The aqueous medium (b) is one selected from water, hydrophilic solvents, and mixtures containing water and hydrophilic solvents. Examples of hydrophilic solvents include methanol, ethanol, isopropyl alcohol, and N-methylpyrrolidone. From the viewpoint of polymerization stability, the aqueous medium (b) is preferably water. As the aqueous medium (b), a mixture obtained by adding a hydrophilic solvent to water can be used as long as the polymerization stability is not impaired.

[0182] 〔Non-polymerizable surfactant (c)〕

[0183] In the case of producing the composite particles (P) by emulsion polymerization, a non-polymerizable surfactant (c) can be included in the solution containing the polyrotaxane 2, the aqueous medium (b), and the raw material monomer (a) for emulsion polymerization. The non-polymerizable surfactant (c) refers to a surfactant (c) that does not have a polymerizable unsaturated bond in its chemical structure. The surfactant (c) improves the dispersion stability of the solution in emulsion polymerization and / or the dispersion (emulsion) obtained after polymerization. As the surfactant (c), an anionic surfactant or a non-ionic surfactant is preferably used.

[0184] Examples of anionic surfactants include alkylbenzene sulfonates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, and fatty acid salts.

[0185] Examples of non-ionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polycyclic phenyl ethers, polyoxyalkylene alkyl ethers, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters.

[0186] The above surfactant (c) can be used alone or in combination of two or more.

[0187] 〔Basic substance (d)〕

[0188] In the case of producing the composite particles (P) by emulsion polymerization, a basic substance (d) may also be added to the solution for emulsion polymerization containing the polyrotaxane 2, the aqueous medium (b) and the raw material monomer (a), and / or the dispersion liquid after emulsion polymerization. By adding the basic substance (d), the acidic components contained in the raw material monomer (a) are neutralized. As a result, the pH of the solution during emulsion polymerization and / or the dispersion liquid after emulsion polymerization becomes an appropriate range, and the stability of the solution during emulsion polymerization and / or the dispersion liquid after emulsion polymerization becomes good.

[0189] Examples of the basic substance (d) added to the solution for emulsion polymerization and / or the dispersion liquid after emulsion polymerization include ammonia, triethylamine, sodium hydroxide, lithium hydroxide, etc. These basic substances (d) may be used alone, or two or more of them may be used in combination.

[0190] 〔Free radical polymerization initiator (e)〕

[0191] The free radical polymerization initiator (e) used when producing the composite particles (P) by emulsion polymerization is not particularly limited, and known substances can be used. Examples of the free radical polymerization initiator (e) include persulfates such as ammonium persulfate and potassium persulfate; hydrogen peroxide; azo compounds; organic peroxides such as tert-butyl hydroperoxide, tert-butyl peroxybenzoate, and cumene hydroperoxide, etc.

[0192] In the present embodiment, when producing the composite particles (P) by emulsion polymerization, redox polymerization may also be carried out by using a reducing agent such as sodium bisulfite, Rongalite, and ascorbic acid together with the free radical polymerization initiator (e).

[0193] The addition amount of the free radical polymerization initiator (e) (including the reducing agent in the case of using a reducing agent in combination) is preferably 0.001 part by mass or more, more preferably 0.002 part by mass or more, based on 100 parts by mass of the raw material monomer (a). The reason is that when producing the composite particles (P) by emulsion polymerization, the conversion rate of the raw material monomer (a) to the composite particles (P) can be high. The addition amount of the free radical polymerization initiator (e) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of the raw material monomer (a). The reason is that the molecular weight of the copolymer contained in the composite particles (P) can be high, and the swelling rate of the non-aqueous secondary battery electrode containing the composite particles (P) of the present embodiment in the electrolyte can be reduced.

[0194] 〔Chain transfer agent (f)〕

[0195] When producing composite particles (P) by emulsion polymerization, a chain transfer agent (f) is used to adjust the molecular weight of the copolymer that forms the composite particles (P) obtained by emulsion polymerization. Examples of the chain transfer agent (f) include n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, 2-ethylhexyl thioglycolate, 2-mercaptoethanol, β-mercaptopropionic acid, methanol, n-propanol, isopropanol, n-butanol, benzyl alcohol, and the like.

[0196] 〔Emulsion polymerization method〕

[0197] As the emulsion polymerization method used when producing composite particles (P), for example, a method of continuously supplying each component used in emulsion polymerization into a reaction vessel while performing emulsion polymerization can be mentioned. The temperature of the emulsion polymerization is not particularly limited, for example, it is 30 to 90°C, preferably 50 to 85°C, and more preferably 55 to 80°C. The emulsion polymerization is preferably carried out while stirring. In addition, it is preferred to continuously supply the raw material monomer (a), polyrotaxane 2, and the radical polymerization initiator (e) to the solution in the emulsion polymerization so that the concentrations of the raw material monomer (a), polyrotaxane 2, and the radical polymerization initiator (e) in the solution during the emulsion polymerization become uniform.

[0198] <2. Binder for non-aqueous secondary battery>

[0199] The binder for non-aqueous secondary battery of this embodiment contains the composite particles (P) of this embodiment. The electrode binder for non-aqueous secondary battery may contain other components together with the composite particles (P). Specifically, the electrode binder for non-aqueous secondary battery may also contain, for example, polymers, surfactants, etc. other than the composite particles (P).

[0200] The binder for non-aqueous secondary battery is composed of components that do not volatilize and remain even when a heating step is performed in the manufacturing method of the non-aqueous secondary battery described later. Specifically, the components constituting the binder for non-aqueous secondary battery are the components remaining after weighing 1 g of the binder composition for non-aqueous secondary battery containing the composite particles (P), placing it on an aluminum dish with a diameter of 5 cm, putting it into a dryer, and drying it for 1 hour at 1 atm (1013 hPa) and a temperature of 105°C while circulating the air in the dryer.

[0201] The content rate of the composite particles (P) contained in the binder for non-aqueous secondary battery is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and further preferably 98% by mass or more. The reason is that the effects brought about by containing the composite particles (P) become significant.

[0202] <3. Binder composition for non-aqueous secondary battery>

[0203] The binder composition for non-aqueous secondary batteries of the present embodiment contains the composite particles (P) of the present embodiment and an aqueous medium (B). The binder composition for non-aqueous secondary batteries of the present embodiment is preferably an emulsion in which the composite particles (P) are dispersed in the aqueous medium (B).

[0204] The binder composition for non-aqueous secondary batteries may contain other components together with the composite particles (P) and the aqueous medium (B). Specifically, the binder composition for non-aqueous secondary batteries may contain, for example, the above components used in the synthesis of the composite particles (P).

[0205] 〔Average particle diameter d50 of composite particles (P)〕

[0206] The average particle diameter d50 of the composite particles (P) contained in the binder composition for non-aqueous secondary batteries of the present embodiment is preferably 0.18 μm or more, more preferably 0.20 μm or more. The reason is that if the average particle diameter d50 is 0.18 μm or more, an electrode in which the electrode active material layer is less likely to peel off from the current collector can be formed.

[0207] The average particle diameter d50 of the composite particles (P) contained in the binder composition for non-aqueous secondary batteries of the present embodiment is preferably 1.0 μm or less, more preferably 0.80 μm or less, further preferably 0.60 μm or less, and particularly preferably 0.50 μm or less. If the average particle diameter d50 of the composite particles (P) is 1.0 μm or less, when pressing an electrode sheet in which an electrode active material layer 24 is formed on a current collector 23 in order to manufacture an electrode containing the binder polymer (P), it can be pressed under suitable pressing conditions. As a result, the electrode active material layer 24 can be more firmly bonded to the current collector 23.

[0208] The average particle diameter d50 of the composite particles (P) of the present embodiment can be adjusted by a known method. For example, it can be adjusted by the addition amount of a surfactant, the selection of raw material monomers, etc. when manufacturing the composite particles (P) by emulsion polymerization.

[0209] The binder composition for non-aqueous secondary batteries of the present embodiment may be a dispersion obtained by manufacturing the composite particles (P) by emulsion polymerization. That is, the binder composition for non-aqueous secondary batteries may be an emulsion containing the composite particles (P) and the aqueous medium (B). In addition, the binder composition for non-aqueous secondary batteries of the present embodiment may be a dispersion obtained by dispersing the composite particles (P) obtained by a method other than emulsion polymerization in the aqueous medium (B). In this case, as a method of dispersing the composite particles (P) in the aqueous medium (B), a known method can be used.

[0210] 〔Aqueous medium (B)〕

[0211] The aqueous medium (B) in the non-aqueous secondary battery binder composition of the present embodiment is water, a hydrophilic solvent, or a mixture thereof. As the hydrophilic solvent, the same substances as those exemplified for the aqueous medium (b) used in the synthesis of the composite particles (P) can be mentioned. The aqueous medium (B) and the aqueous medium (b) used in the synthesis of the composite particles (P) may be the same or different.

[0212] In the case where the non-aqueous secondary battery binder composition is an emulsion obtained by producing the composite particles (P) using the emulsion polymerization method, the aqueous medium (B) may be the aqueous medium (b) used in the synthesis of the composite particles (P). Further, the aqueous medium (B) may also be a substance in which a new aqueous medium is added to the aqueous medium (b) used in the synthesis of the composite particles (P). Further, the aqueous medium (B) may also be a substance in which part or all of the aqueous medium (b) contained in the dispersion obtained by producing the composite particles (P) using the emulsion polymerization method is replaced with a new aqueous solvent. The new aqueous medium used in this case and the aqueous medium (b) used in the synthesis of the composite particles (P) may have the same composition or different compositions.

[0213] 〔Concentration of non-volatile components in non-aqueous secondary battery binder composition〕

[0214] The concentration of non-volatile components in the non-aqueous secondary battery binder composition of the present embodiment is preferably 20% by mass or more, more preferably 25% by mass or more, and still more preferably 30% by mass or more. The reason is that the amount of the active ingredient contained in the non-aqueous secondary battery binder composition is large. The concentration of non-volatile components in the non-aqueous secondary battery binder composition can be adjusted by the content of the aqueous medium (B) contained in the non-aqueous secondary battery binder composition.

[0215] The concentration of non-volatile components in the non-aqueous secondary battery binder composition is preferably 80% by mass or less, more preferably 70% by mass or less, and still more preferably 60% by mass or less. The reason is that an increase in the viscosity of the non-aqueous secondary battery binder composition is suppressed, and it is easy to prepare a slurry for a non-aqueous secondary battery electrode.

[0216] <4. Slurry for non-aqueous secondary battery electrode>

[0217] Next, the slurry for non-aqueous secondary battery electrodes of the present embodiment will be described in detail. The slurry for non-aqueous secondary battery electrodes contains the composite particles (P) of the present embodiment, an electrode active material, and an aqueous medium. The composite particles (P) and the electrode active material contained in the slurry for non-aqueous secondary battery electrodes are preferably dispersed in the aqueous medium. The slurry for non-aqueous secondary battery electrodes may further contain a thickener, a conductive aid, the above components used in the synthesis of the composite particles (P), etc., in addition to the composite particles (P), the electrode active material, and the aqueous medium.

[0218] 〔Content of composite particles (P)〕

[0219] The content of the composite particles (P) contained in the slurry for non-aqueous secondary battery electrodes is preferably 0.50 parts by mass or more, more preferably 1.0 part by mass or more, relative to 100 parts by mass of the electrode active material. The reason is to fully exhibit the effects brought about by including the composite particles (P).

[0220] The content of the composite particles (P) contained in the slurry for non-aqueous secondary battery electrodes is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and further preferably 3.0 parts by mass or less, relative to 100 parts by mass of the electrode active material. The reason is that the content of the electrode active material contained in the slurry for non-aqueous secondary battery electrodes can be increased.

[0221] 〔Electrode active material〕

[0222] The electrode active material contained in the slurry for non-aqueous secondary battery electrodes is a material capable of inserting (Intercaration) / detaching (Deintercalation) ions such as lithium ions that become charge carriers. The ions that become charge carriers are preferably alkali metal ions, more preferably lithium ions, sodium ions, potassium ions, and further preferably lithium ions.

[0223] When the non-aqueous secondary battery electrode manufactured using the slurry for non-aqueous secondary battery electrodes is a negative electrode, the electrode active material is a negative electrode active material. As the negative electrode active material, it is preferably to contain at least one of a carbon material, a silicon-containing material, and a titanium-containing material. As the carbon material that can be used as the negative electrode active material, for example, coke such as petroleum coke, pitch coke, and coal coke, carbides of organic polymers, graphite such as artificial graphite and natural graphite can be cited. As the silicon-containing material that can be used as the negative electrode active material, for example, silicon compounds such as elemental silicon and silicon oxide can be cited. As the titanium-containing material that can be used as the negative electrode active material, for example, lithium titanate can be cited. These materials that can be used as the negative electrode active material can be used alone, or can be used in a mixture or composite form.

[0224] The negative electrode active material preferably contains at least one of a carbon material and a silicon-containing material, and more preferably contains a carbon material. The reason is that the effect of improving the adhesiveness between the negative electrode active materials and between the negative electrode active material and the current collector brought about by the composite particles (P) contained in the non-aqueous secondary battery electrode paste is great.

[0225] When the non-aqueous secondary battery electrode manufactured using the non-aqueous secondary battery electrode paste is a positive electrode, the electrode active material is a positive electrode active material. As the positive electrode active material, a material having a higher standard electrode potential than the negative electrode active material is used. Specifically, as the positive electrode active material, nickel-containing lithium composite oxides such as Ni-Co-Mn-based lithium composite oxides, Ni-Mn-Al-based lithium composite oxides, Ni-Co-Al-based lithium composite oxides, lithium cobaltate (LiCoO2), spinel-type lithium manganate (LiMn2O4), olivine-type lithium iron phosphate, chalcogenide compounds such as TiS2, MnO2, MoO3, V2O5, etc. can be cited. These substances that can be used as the positive electrode active material can be used alone, only one kind, or two or more kinds can be used in combination.

[0226] 〔Aqueous medium〕

[0227] The aqueous medium contained in the non-aqueous secondary battery electrode paste of the present embodiment is one selected from water, a hydrophilic solvent, and a mixture containing water and a hydrophilic solvent. As the hydrophilic solvent, the same substances as those exemplified as the hydrophilic solvent (b) used in the synthesis of the composite particles (P) can be cited. The aqueous medium contained in the non-aqueous secondary battery electrode paste and the aqueous medium (b) used in the synthesis of the composite particles (P) may be the same or different.

[0228] 〔Thickener〕

[0229] As the thickener that can be contained in the non-aqueous secondary battery electrode paste, cellulose-based substances such as carboxymethyl cellulose (CMC), hydroxyethyl cellulose, hydroxypropyl cellulose, ammonium salts of cellulose-based substances, alkali metal salts of cellulose-based substances, polyvinyl alcohol, polyvinylpyrrolidone, etc. can be cited. The thickener preferably contains at least one of carboxymethyl cellulose, ammonium salt of carboxymethyl cellulose, and alkali metal salt of carboxymethyl cellulose. The reason is that the electrode active material in the non-aqueous secondary battery electrode paste is easily dispersed.

[0230] The content of the thickener contained in the non-aqueous secondary battery electrode paste is preferably 0.50 parts by mass or more, more preferably 0.80 parts by mass or more, relative to 100 parts by mass of the electrode active material. The reason is that the adhesiveness between the electrode active materials contained in the non-aqueous secondary battery electrode produced using the non-aqueous secondary battery electrode paste and between the electrode active material and the current collector becomes good.

[0231] The content of the thickener contained in the non-aqueous secondary battery electrode paste is preferably 3.0 parts by mass or less, more preferably 2.0 parts by mass or less, and further preferably 1.5 parts by mass or less with respect to 100 parts by mass of the electrode active material. The reason is that the coatability of the non-aqueous secondary battery electrode paste becomes good.

[0232] [Conductive aid]

[0233] Examples of the conductive aid that can be contained in the non-aqueous secondary battery electrode paste of the present embodiment include carbon black, carbon fiber, etc. Examples of carbon black include furnace black, acetylene black, Denka Black (registered trademark) (manufactured by Denka Co., Ltd.), Ketjen Black (registered trademark) (manufactured by Ketjen Black International Co., Ltd.), etc. Examples of carbon fiber include carbon nanotubes, carbon nanofibers, etc. As the carbon nanotubes, VGCF (registered trademark, manufactured by Showa Denko K.K.), which is a vapor-grown carbon fiber, is cited as a preferred example.

[0234] [Method for manufacturing non-aqueous secondary battery electrode paste]

[0235] Examples of the method for manufacturing the non-aqueous secondary battery electrode paste of the present embodiment include a method of mixing the composite particles (P) of the present embodiment, the electrode active material, the aqueous medium, the thickener contained as needed, the conductive aid contained as needed, and other components contained as needed. The mixing order of the respective components as raw materials of the non-aqueous secondary battery electrode paste is not particularly limited and can be appropriately determined. Examples of the method for mixing the respective components include a method using a mixing device such as a stirring type, a rotary type, or an oscillating type.

[0236] <5. Non-aqueous secondary battery electrode>

[0237] Next, the non-aqueous secondary battery electrode of the present embodiment will be described in detail. The electrode of the present embodiment contains the composite particles (P) of the present embodiment. The electrode of the present embodiment includes a current collector and an electrode active material layer formed on the current collector. Examples of the shape of the electrode of the present embodiment include a laminate, a wound body, etc., and there is no particular limitation.

[0238] The formation range of the electrode active material layer on the current collector is not particularly limited, and the electrode active material layer can be formed on the entire surface of the current collector, or can be formed only on a part of the surface of the current collector. When the current collector is in the shape of a plate, a foil, etc., the electrode active material layer can be formed on both sides of the current collector, or can be formed only on one side.

[0239] [Current collector]

[0240] The current collector is preferably a metal sheet with a thickness of 0.001 mm or more and 0.5 mm or less. Examples of the metal for forming the metal sheet include iron, copper, aluminum, nickel, stainless steel, etc. When the electrode in the present embodiment is the negative electrode of a lithium-ion secondary battery, the current collector is preferably a copper foil.

[0241] 〔Electrode active material layer〕

[0242] The electrode active material layer contains the composite particles (P) of the present embodiment and an electrode active material. The electrode active material layer may also contain a conductive additive, a thickener, etc. The electrode active material, the conductive additive, and the thickener can all use the same substances as those exemplified as the components of the non-aqueous secondary battery electrode paste.

[0243] 〔Manufacturing method of non-aqueous secondary battery electrode〕

[0244] The electrode of the present embodiment can be manufactured, for example, by the method shown below. First, the non-aqueous secondary battery electrode paste of the present embodiment is coated on the current collector. Then, the non-aqueous secondary battery electrode paste is dried. Thereby, an electrode active material layer containing the composite particles (P) is formed on the current collector to produce an electrode sheet. Then, if necessary, the electrode sheet is cut into an appropriate size. By performing the above processes, the electrode of the present embodiment is obtained.

[0245] As a method of coating the non-aqueous secondary battery electrode paste on the current collector, there is no particular limitation, and examples include a reverse roll method, a direct roll method, a doctor blade method, a knife method, an extrusion method, a curtain method, an intaglio method, a bar method, an impregnation method, an extrusion method, etc. Among these coating methods, if the physical properties such as the viscosity of the non-aqueous secondary battery electrode paste and the drying property are considered, it is preferable to use any one method selected from the direct roll method, the doctor blade method, the knife method, or the extrusion method. The reason is that an electrode active material layer with a smooth surface and small thickness unevenness can be obtained.

[0246] When coating the non-aqueous secondary battery electrode paste on both sides of the current collector, it can be coated one by one sequentially, or coated on both sides simultaneously. In addition, the non-aqueous secondary battery electrode paste can be coated continuously or intermittently on the current collector.

[0247] The coating amount of the non-aqueous secondary battery electrode paste can be appropriately determined according to the design capacity of the battery and the composition of the non-aqueous secondary battery electrode paste, etc.

[0248] As a method of drying the non-aqueous secondary battery electrode paste coated on the current collector, there is no particular limitation. For example, a method selected from hot air, reduced pressure or vacuum environment, (far) infrared rays, and low-temperature wind can be used alone or in combination.

[0249] When drying the non-aqueous secondary battery electrode paste, the drying temperature and drying time can be appropriately adjusted according to the concentration of the non-volatile components in the non-aqueous secondary battery electrode paste, the coating amount on the current collector, etc. The drying temperature is preferably 40°C or higher and 350°C or lower, and from the viewpoint of productivity, more preferably 60°C or higher and 100°C or lower. The drying time is preferably 1 minute or longer and 30 minutes or shorter.

[0250] The electrode sheet on which the electrode active material layer is formed on the current collector can be cut to have an appropriate size and shape as an electrode. The cutting method of the electrode sheet is not particularly limited, and for example, slitting, laser, wire cutting, cutter, Thomson cutter, etc. can be used.

[0251] In the present embodiment, before or after cutting the electrode sheet, the electrode sheet can be pressed as needed. Thereby, the electrode active material can be more firmly bonded to the current collector, and the non-aqueous secondary battery can be miniaturized by thinning the thickness of the electrode.

[0252] As a pressing method of the electrode sheet, a general method can be used. As the pressing method, die pressing method or roll pressing method is particularly preferably used.

[0253] In the case of using the die pressing method, the pressing pressure is not particularly limited, and is preferably 0.5 t / cm 2 or more and 5 t / cm 2 or less.

[0254] In the case of using the roll pressing method, the pressing load is not particularly limited, and is preferably 0.5 t / cm or more and 8 t / cm or less. The reason is that while obtaining the above effects brought by pressing, the decrease in the insertion and extraction capacity of charge carriers such as lithium ions into and from the electrode active material can be suppressed.

[0255] <6. Non-aqueous secondary battery>

[0256] Next, as a preferred example of the non-aqueous secondary battery according to the present embodiment, a lithium ion secondary battery will be described. It should be noted that the configuration of the non-aqueous secondary battery of the present invention is not limited to the example shown below.

[0257] The lithium ion secondary battery of the present embodiment is a substance in which a positive electrode, a negative electrode, an electrolyte, and a separator (if any) are housed in an outer package.

[0258] The shape of the lithium ion secondary battery can be any shape such as coin type, button type, sheet type, cylindrical type, square type, flat type, etc.

[0259] 〔Positive electrode / Negative electrode〕

[0260] One or both of the positive electrode and the negative electrode of the lithium-ion secondary battery of the present embodiment include an electrode active material layer containing the composite particles (P) of the present embodiment. In the lithium-ion secondary battery of the present embodiment, it is preferable that at least the negative electrode among the positive electrode and the negative electrode includes an electrode active material layer containing the composite particles (P).

[0261] When only one of the positive electrode and the negative electrode of the lithium-ion secondary battery of the present embodiment includes an electrode active material layer containing the composite particles (P) of the present embodiment, as the electrode that does not contain the composite particles (P) of the present embodiment, a substance containing a known binder such as poly(1,1-difluoroethylene) is used instead of the composite particles (P) of the present embodiment.

[0262] 〔Electrolyte〕

[0263] As the electrolyte, a non-aqueous liquid having ion conductivity is used. Examples of the electrolyte include a solution in which an electrolyte is dissolved in an organic solvent, an ionic liquid, etc., and the former is preferred. The reason is that the manufacturing cost is low and a lithium-ion secondary battery with low internal resistance can be obtained.

[0264] As the electrolyte, an alkali metal salt can be used, and it can be appropriately selected according to the type of the electrode active material, etc. Examples of the electrolyte include, for example, LiClO4, LiBF6, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiB 10 Cl 10 , LiAlCl4, LiCl, LiBr, LiB(C2H5)4, CF3SO3Li, CH3SO3Li, LiCF3SO3, LiC4F9SO3, Li(CF3SO2)2N, lithium aliphatic carboxylate, etc. In addition, as the electrolyte, other alkali metal salts can also be used.

[0265] The organic solvent in which the electrolyte is dissolved is not particularly limited, and examples thereof include carbonate compounds such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), fluoroethylene carbonate (FEC), and vinylene carbonate (VC), nitrile compounds such as acetonitrile, and carboxylic acid esters such as ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and propyl propionate. These organic solvents can be used alone or in combination of two or more. Among them, as the organic solvent, a substance combining linear carbonate solvents is preferably used.

[0266] 〔Outer package〕

[0267] As the outer package, for example, a substance formed of an aluminum laminate composed of an aluminum foil and a resin film can be appropriately used, etc., and it is not limited thereto.

[0268] Example

[0269] Hereinafter, the present invention will be specifically described by way of examples and comparative examples. It should be noted that the following examples are provided to facilitate the understanding of the content of the present invention. The present invention is not limited to these examples.

[0270] In the following examples, as an example of the non-aqueous secondary battery electrode of the present invention, a negative electrode of a lithium-ion secondary battery was fabricated, and as an example of the non-aqueous secondary battery, a lithium-ion secondary battery was fabricated. The effects of the present invention were confirmed by comparing with the negative electrode of the lithium-ion secondary battery and the lithium-ion secondary battery according to the comparative example.

[0271] In addition, the water used in the following examples and comparative examples is ion-exchanged water unless otherwise specified.

[0272] <1. Manufacture of Adhesive Composition for Non-aqueous Secondary Battery>

[0273] (Examples 1 to 11, Comparative Example 2)

[0274] The raw material monomer (a) and the polyrotaxane shown in Tables 1 to 5 were mixed with 200 parts by mass of water as the aqueous medium (b) at the mass ratios shown in Tables 1 to 5 and emulsified to produce a monomer emulsion. Subsequently, an aqueous solution in which the radical polymerization initiator (e) shown in Tables 1 to 5 was dissolved in 50 parts by mass of water was prepared.

[0275] 150 parts by mass of water was added to a detachable flask equipped with a condenser, a thermometer, a stirrer, and a dropping funnel, and the temperature was raised to 75°C. In this detachable flask, the above monomer emulsion and the aqueous solution in which the radical polymerization initiator (e) was dissolved were continuously supplied independently over 3 hours while stirring at 75°C to carry out emulsion polymerization, and an emulsion was obtained.

[0276] The resulting emulsion was cooled to room temperature. Then, 133 parts by mass of water and 25% ammonia water (17 parts by mass of ammonia and 51 parts by mass of water) in the amounts shown in Tables 1 to 5 were added to the emulsion. Thereby, the adhesive compositions for non-aqueous secondary batteries of Examples 1 to 11 and Comparative Example 2, which were composed of emulsions in which the dispersed particles of Examples 1 to 11 and Comparative Example 2 were dispersed in the aqueous medium, were manufactured.

[0277] (Comparative Example 1)

[0278] The raw material monomer (a) shown in Table 5 was mixed with 200 parts by mass of water as the aqueous medium (b) at the mass ratio shown in Table 5 and emulsified to produce a monomer emulsion. Subsequently, an aqueous solution in which the radical polymerization initiator (e) shown in Table 5 was dissolved in 50 parts by mass of water was prepared.

[0279] 150 parts by mass of water was added to a detachable flask equipped with a cooling tube, a thermometer, a stirrer, and a dropping funnel, and the temperature was raised to 75 °C. In this detachable flask, the above monomer emulsion and the aqueous solution in which the above radical polymerization initiator (e) was dissolved were continuously supplied while stirring at 75 °C over 3 hours respectively to carry out emulsion polymerization, and an emulsion was obtained.

[0280] The obtained emulsion was cooled to room temperature. Then, 133 parts by mass of water and 25% ammonia water in the amount shown in Table 5 were added to the emulsion. Thus, a binder composition for non-aqueous secondary batteries of Comparative Example 1 composed of an emulsion in which emulsified particles containing a copolymer were dispersed in an aqueous medium was produced. The emulsified particles in the emulsion of Comparative Example 1 contained a copolymer but did not contain a polyrotaxane.

[0281] (Comparative Example 3)

[0282] The same operation as in Comparative Example 1 was carried out to obtain an emulsion of Comparative Example 3. Therefore, the emulsified particles in this emulsion contained a copolymer but did not contain a polyrotaxane.

[0283] The obtained emulsion was cooled to room temperature. Then, the polyrotaxane shown in Table 5 was added to the emulsion in the amount shown in Table 5, 123 parts by mass of water was further added, and 25% ammonia water in the amount shown in Table 5 was added, and the mixture was stirred with a homogenizer for 30 minutes.

[0284] Thus, a binder composition for non-aqueous secondary batteries of Comparative Example 3 composed of an emulsion in which emulsified particles containing a copolymer and a polyrotaxane were independently dispersed in an aqueous medium was produced respectively.

[0285] For the binder composition for non-aqueous secondary batteries of Comparative Example 3, no dispersion abnormalities such as aggregation of emulsified particles containing a copolymer and a polyrotaxane in the composition were observed. That is, in Comparative Example 3, the composite particles containing a copolymer and a polyrotaxane of the present embodiment were not formed, and the binder composition for non-aqueous secondary batteries of Comparative Example 3 did not contain the composite particles containing a copolymer and a polyrotaxane of the present embodiment.

[0286] It is presumed that this is because, for the binder composition for non-aqueous secondary batteries of Comparative Example 3, the emulsified particles containing a copolymer in the composition and the polyrotaxane repel each other electrically, so the dispersion of the emulsified particles containing a copolymer and the polyrotaxane is maintained respectively.

[0287] [Table 1]

[0288]

[0289] ※1: The values in the right column of the raw material monomer (a) are the content ratios (mass%) of each monomer when the total amount of the raw material monomer (a) is set to 100 parts by mass.

[0290] The value on the right side of the polyrotaxane is the number of parts by mass of the polyrotaxane when the total amount of the raw material monomer (a) is set to 100 parts by mass.

[0291] [Table 2]

[0292]

[0293] ※1: The values in the right column of the raw material monomer (a) are the content ratios (mass%) of each monomer when the total amount of the raw material monomer (a) is set to 100 parts by mass.

[0294] The value on the right side of the polyrotaxane is the number of parts by mass of the polyrotaxane when the total amount of the raw material monomer (a) is set to 100 parts by mass.

[0295] [Table 3]

[0296]

[0297] ※1: The values in the right column of the raw material monomer (a) are the content ratios (mass%) of each monomer when the total amount of the raw material monomer (a) is set to 100 parts by mass.

[0298] The value on the right side of the polyrotaxane is the number of parts by mass of the polyrotaxane when the total amount of the raw material monomer (a) is set to 100 parts by mass.

[0299] [Table 4]

[0300]

[0301] ※1: The values in the right column of the raw material monomer (a) are the content ratios (mass%) of each monomer when the total amount of the raw material monomer (a) is set to 100 parts by mass.

[0302] The value on the right side of the polyrotaxane is the number of parts by mass of the polyrotaxane when the total amount of the raw material monomer (a) is set to 100 parts by mass.

[0303] [Table 5]

[0304]

[0305] ※1: The values in the right column of the raw material monomer (a) are the content ratios (mass%) of each monomer when the total amount of the raw material monomer (a) is set to 100 parts by mass.

[0306] The value on the right side of the polyrotaxane is the mass fraction of the polyrotaxane when the total amount of the raw material monomer (a) is set to 100 parts by mass.

[0307] The polyoxyethylene alkyl ether sulfate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Aqualon KH-10) of the monomer (a4) shown in Tables 1 to 5 is a polymerizable surfactant.

[0308] In the polymerization initiator (e), Rongalite SFS is the trade name of Rongalite manufactured by Sumitomo Seika Chemicals Co., Ltd.

[0309] The polyrotaxane shown in Tables 1 to 5 contains a chain molecule composed of polyethylene glycol (weight average molecular weight: 20,000) and is Selm (registered trademark) super polymer SH2400P (manufactured by Advanced Soft Materials Co., Ltd.) with a weight average molecular weight of 400,000.

[0310] The so-called addition timing shown in Tables 1 to 5 is the timing when the polyrotaxane is used in the manufacturing process of the adhesive composition. The so-called pre-polymerization means that the raw material monomer (a) is copolymerized in the presence of the polyrotaxane. The so-called post-polymerization means that the polyrotaxane is added to an emulsion containing emulsion particles of a copolymer obtained by copolymerizing the raw material monomer (a).

[0311] The amount of ammonia as the basic substance (d) shown in Tables 1 to 5 is the amount of ammonia contained in the aqueous ammonia (parts by mass).

[0312] The amount of water as the aqueous medium (b) shown in Tables 1 to 5 is the total amount of water contained in the non-aqueous secondary battery adhesive composition (parts by mass).

[0313] <2. Evaluation of composite particles and non-aqueous secondary battery adhesive composition>

[0314] Regarding the composite particles of Examples 1 to 11 and Comparative Examples 1 to 3, the glass transition temperature (Tg) and particle size (d50) were measured by the methods shown below. The results are shown in Tables 1 to 5.

[0315] In addition, regarding the non-aqueous secondary battery adhesive compositions of Examples 1 to 11 and Comparative Examples 1 to 3, the non-volatile component concentration was measured by the methods shown below. The results are shown in Tables 1 to 5.

[0316] 〔Glass transition temperature (Tg)〕

[0317] A film with a thickness of 2 mm formed of composite particles was obtained by applying an adhesive composition for non-aqueous secondary batteries onto a release PET (polyethylene terephthalate) film and drying it at 50 °C for 5 hours.

[0318] A test piece in the shape of a 2 mm by 2 mm square was cut out from the obtained film. The test piece was sealed in an aluminum pan, and differential scanning calorimetry (DSC) measurement of the test piece was performed using a differential scanning calorimeter (EXSTAR DSC / SS7020 manufactured by Hitachi High-Tech Science Corporation) at a heating rate of 10 °C / minute in a nitrogen atmosphere. The temperature range for the DSC measurement was set to -40 °C to 200 °C. Furthermore, the peak temperature of the DDSC curve obtained as the temperature derivative of the DSC was measured, and this temperature was set as the glass transition temperature Tg (°C) of the composite particles.

[0319] [Particle size (d50) of the composite particles in the adhesive composition for non-aqueous secondary batteries]

[0320] The adhesive composition for non-aqueous secondary batteries was measured at room temperature by dynamic light scattering (DLS) using NANOTORAC WAVE II (manufactured by Microtrac·Bell Co., Ltd.), and thus the particle size (d50) of the composite particles was measured on a volume basis using the particle refractive index.

[0321] [Non-volatile component concentration]

[0322] 1 g of the adhesive composition for non-aqueous secondary batteries was weighed, placed on an aluminum dish with a diameter of 5 cm, and put into a dryer. While circulating the air in the dryer, it was dried at 1 atm (1013 hPa) and a temperature of 105 °C for 1 hour, and the mass of the remaining components was measured. The mass ratio (mass %) of the above components remaining after drying with respect to the mass (1 g) of the adhesive composition for non-aqueous secondary batteries before drying was calculated and set as the non-volatile component concentration (mass %).

[0323] <3. Manufacture of non-aqueous secondary batteries>

[0324] The adhesive compositions for non-aqueous secondary batteries of Examples 1 to 11 and Comparative Examples 1 to 3 were respectively used to fabricate a negative electrode by the method shown below, and a lithium-ion secondary battery as the non-aqueous secondary batteries of Examples 1 to 11 and Comparative Examples 1 to 3 was fabricated using this negative electrode.

[0325] [Fabrication of the positive electrode]

[0326] LiNi as the positive electrode active material 0.6 Mn 0.2 Co 0.294 parts by mass of O2, 3 parts by mass of acetylene black as a conductive additive, and 3 parts by mass of poly(1,1-difluoroethylene) as a binder were mixed to obtain a mixture. 50 parts by mass of N-methylpyrrolidone was added to the resulting mixture and further mixed to obtain a positive electrode paste.

[0327] As the positive electrode current collector, an aluminum foil with a thickness of 15 μm was prepared. The positive electrode paste was coated on both sides of the positive electrode current collector by the direct roll method. The coating amount of the positive electrode paste on the positive electrode current collector was adjusted so that the thickness after the following roll pressing treatment became 125 μm on each side.

[0328] The positive electrode paste coated on the positive electrode current collector was dried at 120 °C for 5 minutes and pressed by the roll pressing method using a roll press (manufactured by Sanku Metal Co., Ltd., pressing load 5 t / cm, roll width 7 cm) to obtain a positive electrode sheet having positive electrode active material layers on both sides of the positive electrode current collector. The obtained positive electrode sheet was cut into a rectangle with a length of 50 mm and a width of 40 mm, and a conductive sheet was connected to serve as the positive electrode.

[0329] [Fabrication of Negative Electrode (Non-aqueous Secondary Battery Electrode)]

[0330] 96.9 parts by mass of artificial graphite (G49, manufactured by Jiangxi Zichen Technology Co., Ltd.) as the negative electrode active material, 3.6 parts by mass of any non-aqueous secondary battery binder composition manufactured in Examples 1 to 11 and Comparative Examples 1 to 3 (1.4 parts by mass of non-volatile component (binder polymer)), and 60 parts by mass of a 2% aqueous solution of CMC (carboxymethyl cellulose-sodium salt, manufactured by Nippon Paper Chemicals Co., Ltd., Sunrose (registered trademark) MAC500LC) were mixed, and 16 parts by mass of water was further added and mixed using a rotating and revolving mixer (ARE-310, manufactured by Shinki Co., Ltd.) to obtain a negative electrode paste (paste for non-aqueous secondary battery electrode).

[0331] As the negative electrode current collector, a copper foil with a thickness of 10 μm was prepared. The negative electrode paste was coated on both sides of the negative electrode current collector by the direct roll method. The coating amount of the negative electrode paste on the negative electrode current collector was adjusted so that the thickness of the negative electrode active material layer after the following roll pressing treatment became 170 μm on each side.

[0332] The negative electrode paste coated on the negative electrode current collector was dried at 90 °C for 10 minutes and pressed by the roll pressing method using a roll press (manufactured by Sanku Metal Co., Ltd., pressing load 8 t / cm, roll width 7 cm). Thus, a negative electrode sheet having negative electrode active material layers on both sides of the negative electrode current collector was obtained. The obtained negative electrode sheet was cut into a rectangle with a length of 52 mm and a width of 42 mm, and a conductive sheet was connected to serve as the negative electrode.

[0333] [Manufacture of Non-aqueous Secondary Battery]

[0334] A separator made of a polyolefin-based porous film (made of polyethylene, thickness 25 μm) is interposed between the positive electrode and the negative electrode, and they are laminated in such a way that the positive electrode active material layer and the negative electrode active material layer face each other, and then they are housed in an exterior body (battery pack) made of an aluminum laminate. Then, an electrolytic solution is injected into the exterior body, vacuum impregnation is carried out, and packaging is performed using a vacuum heat sealer, thereby obtaining a lithium-ion secondary battery.

[0335] As the electrolytic solution, a substance in which 99 mass parts of a solution in which LiPF6 is dissolved at a concentration of 1.0 mol / L and 1 mass part of vinylene carbonate (VC) are mixed in a mixed solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of EC:EMC:DEC = 30:50:20 is used.

[0336] <4. Evaluation of Non-aqueous Secondary Battery>

[0337] Regarding the lithium-ion secondary batteries of Example 1 to Example 11 and Comparative Example 1 to Comparative Example 3, the internal resistance and the discharge capacity retention rate after 500 cycles were evaluated by the methods shown below, respectively. The results are shown in Tables 1 to 5.

[0338] [Internal Resistance (DCR)]

[0339] Under the condition of 25 °C, the internal resistance (DCR (Ω)) of the lithium-ion secondary battery was measured by the following steps. That is, from the open-circuit potential, constant current charging was carried out at 0.2C until the voltage reached 3.6V, and the charging state was made 50% of the initial capacity (SOC50%). Then, discharging was carried out at each current value of 0.2C, 0.5C, 1C, and 2C for 60 seconds. The internal resistance DCR (Ω) at SOC50% was determined from the relationship between these 4 current values (values for 1 second) and the voltage.

[0340] [Discharge Capacity Retention Rate after 500 Cycles]

[0341] Under the condition of 45 °C, a series of operations of the following steps (i) to (iv) was set as 1 cycle, and charge and discharge were carried out. The time integral value of the current in steps (i) and (ii) was set as the charge capacity, and the time integral value of the current in step (iv) was set as the discharge capacity. Furthermore, the discharge capacity of the 1st cycle and the discharge capacity of the 500th cycle were measured, and the discharge capacity retention rate after 500 cycles was calculated by the following formula.

[0342] Discharge capacity retention rate (%) = 100 × (Discharge capacity of the 500th cycle / Discharge capacity of the 1st cycle)

[0343] (i) Charge at a current of 1C until the voltage reaches 4.2V (constant current (CC) charging).

[0344] (ii) Charge at a voltage of 4.2V until the current reaches 0.05C (constant voltage (CV) charging).

[0345] (iii) Stand still for 30 minutes.

[0346] (iv) Discharge at a current of 1C until the voltage reaches 2.75V (constant current (CC) discharging).

[0347] <5. Evaluation results>

[0348] As shown in Tables 1 to 5, it was confirmed that the lithium-ion secondary batteries of Examples 1 to 11 had a higher capacity retention rate than the lithium-ion secondary batteries of Comparative Examples 1 to 3. It is presumed that this is because the composite particles contained in the negative electrodes of the lithium-ion secondary batteries of Examples 1 to 11 contain a copolymer containing structural units derived from monomers (a1) and (a2) shown in Tables 1 to 5, and a polyrotaxane shown in Tables 1 to 5.

[0349] More specifically, in Comparative Example 1, a negative electrode was manufactured using a non-aqueous secondary battery binder composition that does not contain a polyrotaxane and in which emulsified particles containing a copolymer are dispersed in an aqueous medium. Therefore, it is presumed that the adhesiveness between the electrode active materials and between the electrode active material and the current collector becomes insufficient, resulting in a poor capacity retention rate.

[0350] In addition, in Comparative Example 2, the composite particles contained in the negative electrode contain a copolymer that does not contain a structural unit derived from monomer (a2) and a polyrotaxane. Therefore, it is presumed that the effect of improving the adhesiveness between the electrode active materials and between the electrode active material and the current collector brought about by the copolymer is insufficient, resulting in a poor capacity retention rate.

[0351] In addition, in Comparative Example 3, compared with Example 1 in which a negative electrode was manufactured using a non-aqueous secondary battery binder composition that uses the same substance as the raw material monomer (a) and contains the same amount of polyrotaxane, the capacity retention rate was poor.

[0352] It is presumed that this is because, in Comparative Example 3, since the polyrotaxane was added to the emulsion containing the emulsified particles containing the copolymer obtained by copolymerizing the raw material monomer (a), the copolymer and the polyrotaxane were not made into composite particles, and between the electrode active materials of the formed electrode and between the electrode active material and the current collector, the copolymer and the polyrotaxane were arranged in a separated state, and the adhesiveness between the electrode active materials and between the electrode active material and the current collector became insufficient.

[0353] In addition, as shown in Tables 1 to 5, it was confirmed that the internal resistances of the lithium-ion secondary batteries of Examples 1 to 11 and Comparative Examples 1 to 3 were sufficiently low values in practical use from the viewpoint of the internal resistance as a secondary effect.

[0354] Industrial Applicability

[0355] Composite particles that can be used as a binder material and a method for producing the same can be provided, and the binder material can form an electrode of a non-aqueous secondary battery having excellent cycle characteristics.

[0356] A binder composition for a non-aqueous secondary battery and a slurry for a non-aqueous secondary battery electrode that can form an electrode of a non-aqueous secondary battery having excellent cycle characteristics can be provided.

[0357] A non-aqueous secondary battery electrode having excellent cycle characteristics and a non-aqueous secondary battery having excellent cycle characteristics including the non-aqueous secondary battery electrode can be provided.

[0358] Explanation of Symbols

[0359] 1 Copolymer

[0360] 2 Polyrotaxane

[0361] 3 Particle Structure

[0362] 4, 42 Surfactant

[0363] 10, 11 Composite Particles

[0364] 20 Electrode

[0365] 21 Thickener

[0366] 22 Electrode Active Material

[0367] 23 Current Collector

[0368] 24 Electrode Active Material Layer

[0369] 25 Binder

[0370] 40 Copolymer Particles

[0371] 51 Cyclic Molecule

[0372] 52 Blocking Group

[0373] 53 Chain-like Molecule

[0374] 54 Modifying Group

[0375] 55 Opening.

Claims

1. A composite particle, which is a composite particle containing a copolymer and a polyrotaxane, The copolymer has a first structural unit derived from monomer a1 and a second structural unit derived from monomer a2, The monomer a1 is a nonionic compound having only one ethylenically unsaturated bond, The monomer a2 is a compound having a carboxyl group and only one ethylenically unsaturated bond, The polyrotaxane includes a cyclic molecule having a cyclic skeleton, and a chain molecule that penetrates the opening of the cyclic molecule and has blocking groups at both ends, and does not contain an ethylenically unsaturated bond.

2. The composite particle according to claim 1, wherein at least a part of the polyrotaxane is present inside a particulate structure formed by the chain molecules of the copolymer.

3. The composite particle according to claim 1 or 2, wherein at least one of the cyclic skeletons in the cyclic molecule is a crown ether skeleton, a cyclic siloxane skeleton, or a cyclic oligosaccharide skeleton.

4. The composite particle according to claim 1 or 2, wherein at least one of the cyclic skeletons in the cyclic molecule is an α-cyclodextrin skeleton.

5. The composite particle according to claim 1 or 2, wherein at least one of the blocking groups is dinitrophenyl, adamantyl, trityl, or a derivative group of any of these groups.

6. The composite particle according to claim 1 or 2, wherein at least one of the blocking groups is adamantyl.

7. The composite particle according to claim 1 or 2, wherein the chain molecule is at least one selected from polyethylene glycol, polypropylene glycol, polyisoprene, polyisobutene, polybutadiene, polytetrahydrofuran, polyacrylate, polydimethylsiloxane, polyethylene, and polypropylene.

8. The composite particle according to claim 1 or 2, wherein at least one of the chain molecules is polyethylene glycol.

9. The composite particle according to claim 1 or 2, wherein the weight-average molecular weight of the chain molecule is 5,000 to 50,000.

10. The composite particle according to claim 1 or 2, wherein the content of the polyrotaxane relative to 100 parts by mass of the copolymer is 0.10 part by mass or more and 50 parts by mass or less.

11. The composite particle according to claim 1 or 2, wherein the content ratio of the second structural unit in all the structural units of the copolymer is 0.10 mass% or more and 20 mass% or less.

12. The composite particle according to claim 1 or 2, wherein the copolymer has a third structural unit derived from monomer a3, The monomer a3 is a compound having a plurality of independent ethylenically unsaturated bonds.

13. The composite particle according to claim 12, wherein the content ratio of the third structural unit in all the structural units of the copolymer is 0.010 mass% or more and 10 mass% or less.

14. The composite particle according to claim 1 or 2, which is used as an adhesive for non-aqueous secondary batteries.

15. An adhesive composition for non-aqueous secondary batteries, which contains the composite particle according to claim 1 or 2 and an aqueous medium.

16. The adhesive composition for non-aqueous secondary batteries according to claim 15, wherein the average particle diameter d50 of the composite particle is 0.18 μm or more and 1.0 μm or less.

17. A slurry for a non-aqueous secondary battery electrode, which contains the composite particles according to claim 1 or 2, an electrode active material, and an aqueous medium.

18. A non-aqueous secondary battery electrode, which contains the composite particles according to claim 1 or 2.

19. A non-aqueous secondary battery, which includes the non-aqueous secondary battery electrode according to claim 18.

20. A method for manufacturing composite particles, which includes the following steps: a polymerization step of subjecting a raw material monomer a containing a monomer a1 and a monomer a2 to emulsion polymerization in the presence of a polyrotaxane, wherein the monomer a1 is a non-ionic compound having only one ethylenically unsaturated bond, the monomer a2 is a compound having a carboxyl group and only one ethylenically unsaturated bond, the polyrotaxane includes a cyclic molecule having a cyclic skeleton, and a chain-like molecule passing through an opening of the cyclic molecule and having blocking groups at both ends, and does not have an ethylenically unsaturated bond.

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