Composition for forming nonaqueous electrolyte secondary battery laminated separator and use thereof

Abstract

To provide a composition for forming a laminated separator for a nonaqueous electrolyte secondary battery, capable of reducing an increase in air permeability of the laminated separator and improving heat resistance.SOLUTION: A composition for forming a nonaqueous electrolyte secondary battery laminated separator according to the present disclosure contains a resin having an amide bond, the resin having an amide bond contains a component that elutes into N-methyl-2-pyrrolidone, and a content of the component that elutes into N-methyl-2-pyrrolidone is more than 25.0% by weight and 45.0% by weight or less based on a total weight of the resin having an amide bond.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition for forming a laminate separator for a non-aqueous electrolyte secondary battery and its use. [Background technology]

[0002] Non-aqueous electrolyte secondary batteries, especially lithium ion secondary batteries, have a high energy density and are therefore widely used as batteries for personal computers, mobile phones, personal digital assistants, etc., and recently development has been progressing for use as batteries for automobiles.

[0003] As a separator, which is a component of the non-aqueous electrolyte secondary battery, for example, a laminate separator formed by laminating a porous layer such as a heat-resistant layer on one or both sides of a polyolefin porous film has been conventionally used. In recent years, with the trend toward higher battery capacities, there has been an increasing demand for laminate separators with high voltage resistance. As a laminate separator that meets this demand, a laminate separator having the following characteristics (a) and (b) has been developed, as described in Patent Document 1: (a) A porous layer is laminated on one or both sides of a polyolefin porous film; (b) The porous layer includes an aramid resin that is a block copolymer having a structure in which some aromatic rings are linked together by sulfonyl bonds, more specifically, a structure having a block with many sulfonyl groups and a block with few sulfonyl groups, and a filler. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-42995 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned conventional techniques have room for further improvement in terms of achieving both air permeability and heat resistance of the laminate separator. One aspect of the present invention aims to realize a composition for forming a laminate separator for a non-aqueous electrolyte secondary battery, which can reduce the increase in air permeability of the laminate separator and improve the heat resistance. [Means for solving the problem]

[0006] In order to solve the above problems, a composition for forming a laminate separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention includes a resin having an amide bond, the resin having an amide bond includes a component that elutes in N-methyl-2-pyrrolidone, and the content of the component that elutes in N-methyl-2-pyrrolidone is more than 25.0 wt % and not more than 45.0 wt % based on the total weight of the resin having an amide bond. [Effects of the Invention]

[0007] According to one aspect of the present invention, it is possible to provide a composition for forming a laminate separator for a non-aqueous electrolyte secondary battery, which can reduce the increase in air permeability of the laminate separator and improve the heat resistance. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the present invention will be described below, but the present invention is not limited thereto. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more and B or less."

[0009] 1. Composition for forming laminated separator for non-aqueous electrolyte secondary battery A composition for forming a laminate separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention includes a resin having an amide bond, the resin having an amide bond includes a component that elutes in N-methyl-2-pyrrolidone, and the content of the component that elutes in N-methyl-2-pyrrolidone is more than 25.0 wt % and not more than 45.0 wt % based on the total weight of the resin having an amide bond. Hereinafter, the laminate separator for a non-aqueous electrolyte secondary battery will also be simply referred to as a "laminated separator."

[0010] Here, the content of the component eluted in N-methyl-2-pyrrolidone (NMP) is obtained by performing an extraction operation using NMP on the resin having the amide bond, a composition containing the resin, or a layer containing the composition.

[0011] Generally, the air permeability of a laminated separator obtained by applying a coating liquid to a substrate is increased compared to the air permeability of the substrate itself. On the other hand, the increase in air permeability of a laminated separator containing the composition is reduced due to the size of its pores. This is due to the high affinity between the components in the composition that are extracted with NMP and NMP, a solvent commonly used in coating liquids. Resins containing amide bonds generally form pores when the resin contained in the coating liquid precipitates and forms a network structure after the coating liquid is applied to the substrate. Here, components containing polar functional groups such as carboxyl groups and / or low-molecular-weight cyclic components that dissolve in NMP contained in the composition precipitate near the network structure after the components other than those dissolved in NMP in the composition precipitate to form the network structure. This type of precipitation results in a layer with large pores, thereby reducing the increase in air permeability of a laminated separator containing the composition.

[0012] Furthermore, because the composition contains a high content of polar functional groups such as carboxyl groups and / or low-molecular-weight cyclic components, it has a high affinity with typical substrates used in laminate separators for nonaqueous electrolyte secondary batteries, such as polyolefin porous films. This results in strong adhesion between the layer containing the composition and the substrate. Here, under high-temperature conditions, the layer with low heat resistance and prone to shrinkage, such as the substrate, among the two or more layers constituting the laminate separator, begins to shrink first. In this case, the laminate separator has another layer, such as the layer containing the composition, that is less prone to shrinkage due to heat than the prone-to-shrink layer, laminated on top of the prone-to-shrink layer, which acts as a force to inhibit the shrinkage, thereby maintaining the shape of the entire laminate separator in a high-temperature environment. Here, when the adhesion between the substrate and the layer containing the composition is strong, the force to inhibit the shrinkage is increased, resulting in improved heat resistance of the laminate separator containing the composition.

[0013] <1-1. Resins with amide bonds> The composition includes a resin having an amide bond. The composition includes at least one type of the resin. That is, the resin may be one type of resin or a mixture of two or more types of resins.

[0014] The resin has a structure in which divalent groups are linked by chemical bonds, at least one of which is an amide bond. The resin can be prepared by a polymerization method in which the divalent groups are sequentially linked via the chemical bonds. Thus, the resin obtained by the preparation method can contain a high-molecular-weight chain polymer consisting of a specific number or more of the divalent groups and a specific number or more of the chemical bonds. Meanwhile, the preparation method also produces, as a by-product, a low-molecular-weight chain polymer having fewer divalent groups and fewer chemical bonds than the high-molecular-weight chain polymer due to interruption of the linkage midway.

[0015] During the preparation of the resin, an intermediate product is produced that has fewer divalent groups and fewer chemical bonds than the high-molecular-weight linear polymer. Here, condensation of both ends of the same molecule in the intermediate product produces a cyclic component as a separate by-product. The cyclic component has a structure in which the divalent groups are linked by the chemical bonds and have no terminals. The weight-average molecular weight of the cyclic component is also smaller than that of the high-molecular-weight linear polymer.

[0016] Specifically, in one embodiment of the present invention, the molecular weight of the low-molecular-weight chain polymer, expressed in terms of intrinsic viscosity, is preferably 0.5 to 5.0 dL / g, more preferably 0.7 to 3.5 dL / g, and even more preferably 0.9 to 2.5 dL / g. Also, in one embodiment of the present invention, the molecular weight of the polymer constituting the cyclic component, expressed in terms of intrinsic viscosity, is preferably 0.1 to 3.0 dL / g, and more preferably 0.3 to 1.5 dL / g.

[0017] Furthermore, in one embodiment of the present invention, the amide bond is a bond formed by condensation of an amino group (-NH2) and a carboxylic acid halide (-C(=O)X) (X is a halogen atom such as F, Cl, Br, or I). Therefore, the resin having the amide bond may include a chain polymer whose terminal group is an amino group or a carboxylic acid halide. Note that the carboxylic acid halide is slowly hydrolyzed by water in the solvent to produce hydrogen halide and a carboxy group. Therefore, the resin having the amide bond may include a chain polymer whose both terminals are carboxy groups. A chain polymer whose terminals are carboxy groups has low reactivity with amino groups, so the subsequent reaction of the chain polymer whose both terminals are carboxy groups is likely to stop, resulting in a low molecular weight chain polymer.

[0018] The low-molecular-weight linear polymer and the cyclic component have a low weight-average molecular weight and are therefore highly soluble in organic solvents such as NMP. Furthermore, a linear polymer having carboxyl groups at both ends is more soluble in organic solvents such as NMP than a linear polymer having an amino group at least at one end. Therefore, when an extraction operation is performed using NMP on a resin having an amide bond, a composition containing the resin, or a layer containing the composition, one or more components selected from the low-molecular-weight linear polymer, the cyclic component, and the linear polymer having carboxyl groups at both ends are extracted into the extraction solution. In other words, the "component eluted into NMP" in one embodiment of the present invention is one or more components selected from the group consisting of the cyclic component, the linear polymer having carboxyl groups at both ends, and the low-molecular-weight linear polymer.

[0019] The weights of the resin having an amide bond, the composition containing the resin, or the layer containing the composition are measured before and after the extraction operation, and the difference therebetween can be calculated as the weight of the "component eluted into NMP" contained in the resin having an amide bond, the composition containing the resin, or the layer containing the composition. The weight of the "component eluted into NMP" contained in the resin having an amide bond, the composition containing the resin, or the layer containing the composition can also be measured by measuring the weight of the "component eluted into NMP" contained in the extract.

[0020] In the resin, the proportion of amide bonds among the chemical bonds is preferably 45 to 85%, more preferably 55 to 75%, from the viewpoint of heat resistance of the layer containing the composition.

[0021] The divalent group is not particularly limited. In one embodiment of the present invention, the divalent group preferably contains a divalent aromatic group, and more preferably all of the divalent groups are divalent aromatic groups. The divalent group may be one type of group or two or more types of groups. Good too.

[0022] As used herein, the term "divalent aromatic group" refers to a divalent group containing an unsubstituted or substituted aromatic ring, and preferably refers to a divalent group consisting of an unsubstituted or substituted aromatic ring. The aromatic ring refers to a cyclic compound that satisfies Hückel's rule. Examples of aromatic rings include benzene, naphthalene, anthracene, azulene, pyrrole, pyridine, furan, and thiophene. In one embodiment of the present invention, the aromatic ring is composed only of carbon atoms and hydrogen atoms. In one embodiment of the present invention, the aromatic ring is a benzene ring or a condensed ring of two or more benzene rings (e.g., naphthalene, anthracene, etc.).

[0023] In one embodiment of the present invention, the substituent in the divalent group is not particularly limited. In one embodiment of the present invention, the substituent in the divalent group is preferably an electron-withdrawing substituent from the viewpoint of obtaining a layer that is resistant to deterioration even under high voltage conditions and has high voltage resistance. The electron-withdrawing substituent is not particularly limited, and examples thereof include a carboxy group, an alkoxycarbonyl group, a nitro group, and a halogen atom.

[0024] The chemical bond may be only an amide bond, or may include a bond other than an amide bond. The bond other than an amide bond is not particularly limited, and examples thereof include a sulfonyl bond, an alkenyl bond (e.g., a C1-C5 alkenyl bond), an ether bond, an ester bond, an imide bond, a ketone bond, and a sulfide bond. The bond other than an amide bond may be one type or two or more types.

[0025] In one embodiment of the present invention, the bonds other than the amide bonds preferably include bonds having stronger electron-withdrawing properties than the amide bonds, from the viewpoint of obtaining a layer having high-voltage resistance. Furthermore, from the viewpoint of further improving the high-voltage resistance of the layer, the proportion of the bonds having stronger electron-withdrawing properties than the amide bonds in the chemical bonds is more preferably 15 to 35%, and even more preferably 25 to 35%.

[0026] Examples of bonds having stronger electron-withdrawing properties than the amide bond include, among the chemical bonds listed above, sulfonyl bonds, ester bonds, and the like.

[0027] Specifically, the resin may be, for example, a polyamide, a polyamideimide, or a copolymer of a polyamide or a polyamideimide with a polymer having one or more bonds selected from a sulfonyl bond, an ether bond, and an ester bond. The copolymer may be a block copolymer or a random copolymer.

[0028] The polyamide is preferably an aromatic polyamide. Examples of the aromatic polyamide include fully aromatic polyamide (aramid resin) and semi-aromatic polyamide. The aromatic polyamide is preferably fully aromatic polyamide. Examples of the aromatic polyamide include para-aramid and meta-aramid.

[0029] The polyamideimide is preferably an aromatic polyamideimide. Examples of the aromatic polyamideimide include wholly aromatic polyamideimide and semi-aromatic polyamideimide. The aromatic polyamideimide is preferably wholly aromatic polyamideimide.

[0030] Examples of the polymer that constitutes the copolymer and has at least one bond selected from the group consisting of a sulfonyl bond, an ether bond, and an ester bond include polysulfone, polyether, and polyester.

[0031] In one embodiment, the resin is preferably an aramid resin. The aramid resin is not particularly limited, and examples thereof include a resin containing a block copolymer having a block A mainly composed of a unit represented by the following formula (1) and a block B mainly composed of a unit represented by the following formula (2). -(NH-Ar 1 -NHCO-Ar 2 -CO)- (1) -(NH-Ar 3 -NHCO-Ar 4 -CO)- (2) (In formulas (1) and (2), Ar 1 , Ar 2 , Ar 3 and Ar 4 may be different for each unit, and Ar 1 , Ar 2 , Ar 3 and Ar 4 are each independently a divalent group having one or more aromatic rings, and all Ar 1 More than 50% of the compounds have a structure in which two aromatic rings are connected by a sulfonyl bond, and all Ar 3 Less than 50% of the compounds have a structure in which two aromatic rings are connected by a sulfonyl bond, and all Ar 1 and Ar 3 Of these, 10-70% have a structure in which two aromatic rings are linked by a sulfonyl bond. Of all the units contained in the block A in the block copolymer, the proportion of units of formula (1) is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. The entire block A, excluding the terminals, is represented by units of formula (1). Of all the units contained in the block B, the proportion of units of formula (2) is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. The entire block B, excluding the terminals, is represented by units of formula (2).

[0032] In the block A, at least a part of Ar 1 has a structure in which two aromatic rings are connected by a sulfonyl bond. 3 may have a structure in which two aromatic rings are connected by a sulfonyl bond. 1 and Ar 3 Among these, Ar has a structure in which two aromatic rings are connected by a sulfonyl bond. 1 and Ar 3The lower limit of the proportion is 10% or more, preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more. The upper limit of this proportion is 70% or less, preferably 65% ​​or less, and more preferably 60% or less.

[0033] In the block A, all Ar 1 Among these, Ar has a structure in which two aromatic rings are connected by a sulfonyl bond. 1 The proportion of Ar in the block A is 50% or more, preferably 80% or more, and more preferably 90% or more. 1 However, it may have a structure in which two aromatic rings are linked by a sulfonyl bond.

[0034] In the block B, all Ar 3 Among these, Ar has a structure in which two aromatic rings are connected by a sulfonyl bond. 3 The proportion of Ar in the block B is 50% or less, preferably 20% or less, and more preferably 10% or less. 3 may have a structure other than the structure in which two aromatic rings are connected by a sulfonyl bond.

[0035] Therefore, it can be said that the block A is a block with a relatively large amount of sulfonyl groups, and the block B is a block with a relatively small amount of sulfonyl groups. By using a block copolymer having these two types of blocks as the resin, it is possible to obtain a layer that can achieve both high voltage resistance and adhesiveness, and a laminate separator including this layer.

[0036] The structure in which the two aromatic rings are linked by a sulfonyl bond is not particularly limited, and examples thereof include 4,4'-diphenylsulfonyl, 3,4'-diphenylsulfonyl, and 3,3'-diphenylsulfonyl.

[0037] Examples of structures other than the structure in which the two aromatic rings are linked by a sulfonyl bond are not particularly limited, and include, for example, the structures shown below.

[0038] [ka]

[0039] At least a portion of the units of formula (1) contained in block A may be 4,4'-diphenylsulfonyl terephthalamide. In this case, the lower limit of the proportion of 4,4'-diphenylsulfonyl terephthalamide among the units of formula (1) contained in block A is preferably 50% or more, more preferably 80% or more, and even more preferably 90% or more. 4,4'-diphenylsulfonyl terephthalamide is easy to handle, and the monomer is readily available.

[0040] At least a portion of the units of formula (2) contained in block B may be paraphenylene terephthalamide. In this case, the lower limit of the proportion of paraphenylene terephthalamide among the units of formula (2) contained in block B is preferably 50% or more, more preferably 80% or more, and even more preferably 90% or more. Paraphenylene terephthalamide is easy to handle, and the monomer is readily available.

[0041] The block copolymer may have a structure composed of units other than those represented by formulas (1) and (2). An example of such a structure is a polyimide skeleton.

[0042] The number of blocks contained in the block copolymer is not particularly limited. The block copolymer may have, for example, a diblock structure such as block A-block B, or a triblock structure such as block A-block B-block A or block B-block A-block B. The block copolymer may also have a tetrablock structure such as block A-block B-block A-block B. Of the above structures, a triblock structure of block B-block A-block B is preferred as the structure of the block copolymer.

[0043] The number of units of formula (1) contained in block A in one molecule of the block copolymer is preferably 10 to 1000, more preferably 20 to 300. If the number of units of formula (1) is within the above range, a sufficiently large number of sulfonyl groups will be contained in the molecule, and the high voltage resistance of a layer obtained from the composition and a laminate separator including the layer will be improved. The number of units of the formula (2) is preferably 10 to 500, more preferably 15 to 200. When the number of units of the formula (2) is within the above range, the layer obtained from the composition has high adhesion to other layers or electrodes.

[0044] Here, the number of units of the formula (1) and the formula (2), which are described as preferred values, is the number in the molecule corresponding to the mode of the molecular weight distribution of the block copolymer. The molecular weight distribution of the block copolymer can be experimentally determined, for example, by gel permeation chromatography.

[0045] The molecular weight of the block copolymer, expressed as an intrinsic viscosity, is preferably 0.5 to 5 dL / g, more preferably 0.8 to 2.5 dL / g. When the molecular weight is within the above range, good coatability when forming a layer from the composition and strength of the obtained layer and the laminate separator including the layer can be achieved at the same time.

[0046] When the composition contains the block copolymer, the content thereof is preferably 5 to 80 wt %, and more preferably 10 to 60 wt %, based on 100 wt % of the weight of the solid content contained in the composition. When the content is within the above range, the layer obtained from the composition and the laminate separator including the layer can be imparted with sufficient high-voltage resistance due to the electron-withdrawing property of the sulfonyl group of the block copolymer.

[0047] From the viewpoint of reducing an increase in air permeability, the content of the component eluted into NMP in the composition is 25.0% by weight or more, preferably 28.0% by weight or more, and more preferably 30.0% by weight or more, based on the total weight of the resin having the amide bond.

[0048] From the viewpoint of heat resistance, the content of the component eluted into NMP is 45.0 wt % or less, preferably 42.0 wt % or less, and more preferably 40.0 wt % or less, based on the total weight of the resin having the amide bond. Furthermore, the component eluted into NMP has high solubility in the solvent and is difficult to precipitate. Therefore, if the composition contains an excessive amount of the component eluted into NMP, it may be difficult to form a layer from the composition. From this viewpoint as well, the content of the component eluted into NMP is preferably in the above-mentioned range.

[0049] As the resin, it is preferable to select an aramid resin containing the block copolymer, which has the following characteristics. It has the same structure as block A and contains a large amount of homopolymers and cyclic components (described below) that have low reactivity with terminal monomers and other polymers.

[0050] Hereinafter, a homopolymer having the same structure as the block A and low reactivity with monomers and other polymers at its terminals will be referred to as "homopolymer A." Furthermore, an aramid resin containing the block copolymer having the above characteristics will be referred to as a "modified aramid resin." Homopolymer A and the cyclic component correspond to the components eluted in NMP described above. Therefore, the modified aramid resin can also be said to be a resin containing a larger amount of components eluted in NMP than conventional aramid resins.

[0051] The homopolymer A is a by-product that can be generated during the preparation of the block copolymer. Specifically, the homopolymer A has a structure in which the terminal group is a carboxy group: C(═O)—OH.

[0052] During the preparation of the block copolymer, a homopolymer having the same structure as block B and low reactivity with monomers and other polymers at the terminals is also produced as a by-product. A homopolymer having the same structure as block B and low reactivity with monomers and other polymers at its terminals will be referred to as "homopolymer B." Homopolymer A has a higher affinity with polyolefins that are commonly used as substrates for laminate separators than do block copolymers consisting of block A and block B and homopolymer B.

[0053] Furthermore, a part of the homopolymer A can be converted into a cyclic component by condensation of both ends. Thus, the aramid resin containing the block copolymer can contain the cyclic component in addition to the homopolymer A. Like the homopolymer A, the cyclic component also has high affinity with polyolefins.

[0054] Therefore, since the modified aramid resin contains a large amount of homopolymer A and the cyclic component, it has a high affinity with polyolefin. Therefore, when a layer is formed on a polyolefin porous film using a composition containing the modified aramid resin, the laminate separator has excellent heat resistance, such as shape retention, in a high-temperature environment.

[0055] Furthermore, homopolymer A and the cyclic component have a higher affinity with solvents commonly used in coating solutions, such as NMP, than homopolymer B and a block copolymer consisting of block A and block B. Therefore, homopolymer A and the cyclic component have high solubility in the solvent. Therefore, when a layer is formed from the composition, the block copolymer consisting of block A and block B and homopolymer B first precipitate to form a network structure, and then homopolymer A precipitates near the network structure. This type of precipitation results in a layer with large pores, resulting in a reduced air permeability for the layer and a laminate separator comprising the layer. Therefore, a laminate separator comprising a layer containing a modified aramid resin has a low air permeability and is therefore excellent in terms of air permeability.

[0056] The composition may contain a filler. When the composition contains a filler, the content of the filler in the composition is preferably 20 to 90% by weight, and more preferably 30 to 80% by weight, when the total amount of the resin and the filler is 100% by weight. When the content of the filler is within the above range, the layer obtained from the composition and the laminated separator including the layer can have sufficient ion permeability. Note that the composition may not contain a filler, i.e., the filler content may be 0% by weight.

[0057] The filler types include organic fillers, inorganic fillers, and mixtures thereof.

[0058] Examples of the organic filler include styrene, vinyl ketone, acrylonitrile, methyl methacrylate, ethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, methyl acrylate, and the like, alone or in copolymers of two or more thereof; fluororesins such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, and polyvinylidene fluoride; melamine resin; urea resin; polyolefin; polymethacrylate; and the like. The organic fillers may be used alone or in combination of two or more. Among these organic fillers, polytetrafluoroethylene powder is preferred in terms of chemical stability. Furthermore, polyolefins may be used as the organic filler to improve the shutdown property of the laminate separator. When polyolefins are used as the organic filler, shutdown property can be imparted to the layer obtained from the composition.

[0059] Examples of the inorganic filler include metal oxides, metal nitrides, metal carbides, and metal hydroxides. Examples of inorganic fillers include powders of aluminum oxide (such as alumina), boehmite, silica, titania, magnesia, barium titanate, barium sulfate, magnesium hydroxide, aluminum hydroxide, and calcium carbonate; as well as minerals such as mica, zeolite, kaolin, and talc. The inorganic fillers may be used alone or in combination of two or more. Among these inorganic fillers, aluminum oxide is preferred in terms of chemical stability.

[0060] The shape of the filler may be substantially spherical, plate-like, columnar, needle-like, whisker-like, fibrous, etc., and particles of any shape can be used. The filler is preferably substantially spherical particles because it is easy to form uniform pores.

[0061] The average particle size of the filler is preferably 0.01 to 1 μm, more preferably 0.01 to 0.8 μm. Fillers with an average particle size of 0.01 μm or more tend to increase the size of pores in the layer obtained from the composition. Therefore, even when a laminate separator obtained using a composition containing the filler is compressed in a battery, the ion permeability of the laminate separator is less likely to decrease. Furthermore, irregularities are more likely to form on the surface of the layer obtained from the composition, improving the slipperiness of the laminate separator. On the other hand, when the average particle size of the filler is 1 μm or less, the heat resistance of the laminate separator can be improved and the laminate separator can be made thinner. To achieve both of these properties, fillers with different average particle sizes may be used in combination, or a filler with a wide particle size distribution may be used. In this specification, the "average particle size of the filler" refers to the volume-based average particle size (D50) of the filler. D50 refers to the particle size at which the cumulative distribution on a volume basis is 50%. D50 can be measured, for example, using a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, trade names: SALD2200, SALD2300, etc.).

[0062] The composition may contain other components in addition to the resin having an amide bond and the filler, provided that the object of the present invention is not impaired. Examples of the other components include resins other than the resin having an amide bond and additives commonly used in separators for nonaqueous electrolyte secondary batteries. The other components may be one type or a mixture of two or more types.

[0063] Examples of resins other than the resin having an amide bond include polyolefins, (meth)acrylate resins, fluorine-containing resins, polyester resins, rubbers, resins with a melting point or glass transition temperature of 180°C or higher, water-soluble polymers, polycarbonate, polyacetal, polyether ether ketone, polybenzimidazole, polyurethane, and melamine resin. For example, when a polyamide resin having excellent heat resistance is mixed with a (meth)acrylate resin and / or a fluorine-containing resin having adhesive properties, a layer having both heat resistance and adhesive properties can be obtained. In this case, the form of the (meth)acrylate resin and / or the fluorine-containing resin is not particularly limited, and may be in the form of particles, may be present in a mixed state with the polyamide resin, or may be segregated on the surface of the layer obtained from the composition.

[0064] The polyolefin is not particularly limited, and examples thereof include polyethylene, polypropylene, polybutene, and ethylene-propylene copolymer.

[0065] The (meth)acrylate resin is not particularly limited, and examples thereof include methyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate.

[0066] The fluorine-containing resin is not particularly limited, and examples thereof include polyvinylidene fluoride (PVD F), polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trichloroethylene copolymer, vinylidene fluoride-vinyl fluoride copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer, and the like, and among the above-mentioned fluorine-containing resins, fluorine-containing rubbers having a glass transition temperature of 23°C or lower can be mentioned.

[0067] The polyester resin is not particularly limited, and examples thereof include aromatic polyesters and liquid crystal polyesters. The aromatic polyester is not particularly limited, and examples thereof include polyarylates.

[0068] Examples of the rubbers include styrene-butadiene copolymers and hydrogenated products thereof, methacrylic acid ester copolymers, acrylonitrile-acrylic acid ester copolymers, styrene-acrylic acid ester copolymers, ethylene propylene rubber, and polyvinyl acetate.

[0069] Examples of the resin having a melting point or glass transition temperature of 180° C. or higher include polyphenylene ether, polysulfone, polyethersulfone, polyphenylene sulfide, polyetherimide, polyamideimide, polyetheramide, and polyetheretherketone.

[0070] Examples of the water-soluble polymer include polyvinyl alcohol, polyethylene glycol, cellulose ether, sodium alginate, polyacrylic acid, polyacrylamide, and polymethacrylic acid.

[0071] Examples of the additives include flame retardants, antioxidants, surfactants, and waxes. If the layer obtained from the composition is prone to static electricity, adding an antistatic agent can suppress static electricity in the layer. Furthermore, adding a flame retardant and / or a crosslinking agent can further improve the safety and heat resistance of the separator.

[0072] <1-2. Method for producing the composition> The composition can be produced using a resin having an amide bond, such as the modified aramid resin described above. The method for controlling the content of components eluted into NMP is not particularly limited, but examples thereof include a method of satisfying the production conditions (i) and (ii) described below.

[0073] A method for preparing the modified aramid resin will be described below. First, as a method for preparing the aramid resin containing the block copolymer, for example, the following methods 1 and 2 can be mentioned. By this method, an aramid resin containing a block copolymer having a diblock structure of block A-block B can be prepared. In addition, an aramid resin containing a block copolymer having other block structures can also be prepared by applying the following procedure and production conditions. 1.NH2-Ar 1 -NH2 and X-(O=)C-Ar 2 A dicarboxylic acid halide represented by -C(=O)-X (X is a halogen atom such as F, Cl, Br, or I) is used as a monomer and polymerized according to a known aromatic polyamide polymerization method, thereby synthesizing a block A having a unit of formula (1). 2. After the synthesis of Block A is completed, NH2-Ar 3 -NH2 and X-(O=)C-Ar 4 A known aromatic polyol is prepared by using a dicarboxylic acid halide represented by —C(═O)—X (X is a halogen atom such as F, Cl, Br, or I) as a monomer. Polymerization is carried out according to the amide polymerization method, thereby synthesizing block B having the unit of formula (2) linked to block A.

[0074] A modified aramid resin that can be suitably used for producing the composition can be prepared by a method that satisfies the production conditions shown in the following (i) and (ii) in the method according to the procedures shown in 1. and 2. (i) In the synthesis of block A described in 1. above, the water content of the solvent used is set to be higher than that used in conventional methods for producing block copolymers, for example, preferably 150 ppm or more, more preferably 400 ppm or more, and even more preferably 450 ppm or more. In addition, the water content of the solvent is set to be preferably 700 ppm or less, more preferably 600 ppm or less. (ii) In the synthesis of block A shown in 1 above, the charge ratio, which is the molar ratio of the diamine to the dicarboxylic acid halide, is set to a range close to 1.00, for example, preferably 0.99 to 1.01, more preferably 0.995 to 1.005.

[0075] Here, the aramid resin containing a block copolymer produced by the methods shown in 1. and 2. may contain, as by-products, homopolymer A, homopolymer B, and the cyclic component. Of these, the content of the cyclic component varies depending only on the solid content concentration during the synthesis of block A.

[0076] When the condition (i) is satisfied, in step 1, the terminal group of block A, C(=O)-X (X is a halogen atom such as F, Cl, Br, or I), reacts with water molecules (HO), converting the terminal group into a carboxy group: C(=O)-OH. Here, the carboxy group corresponds to a group that has low reactivity with monomers and other polymers. Therefore, the amount of homopolymer A contained in the block copolymer increases.

[0077] Therefore, when the above condition (i) is satisfied, a modified aramid resin having a high content of homopolymer A and the cyclic component can be suitably prepared.

[0078] On the other hand, when the condition (i) is satisfied, the C(═O)—X group, which is the reaction site, is likely to become a carboxy group that has low reactivity with monomers and other polymers during the polymerization reaction that produces block A. Therefore, when the condition (i) is satisfied, the degree of polymerization of block A decreases, and the weight-average molecular weight of the resulting modified aramid resin is likely to decrease. Here, if the weight-average molecular weight of the modified aramid resin is low, the modified aramid resin has high solubility in solvents and is difficult to precipitate in the method for producing the laminate separator, so there is a risk that a layer will not be formed from the composition, making it impossible to produce the laminate separator.

[0079] However, when the charge ratio is close to 1.00, the number of monomers that become the terminal groups of block A decreases, and the degree of polymerization of block A increases, resulting in a higher weight-average molecular weight of the resulting modified aramid resin. Thus, by satisfying condition (ii), even when condition (i) is satisfied, the weight-average molecular weight of the resulting modified aramid resin can be increased to an extent that allows a layer to be suitably formed from the composition and allows the laminate separator to be suitably produced.

[0080] Furthermore, even if a layer can be formed from the composition, if the water content of the solvent is high, the weight average molecular weight will decrease even if condition (ii) is satisfied, and the heat resistance of the layer may decrease. As described above, by setting the water content of the solvent to 700 ppm or less, a layer with excellent heat resistance is likely to be obtained.

[0081] 2. Layers for forming laminated separators for non-aqueous electrolyte secondary batteries The layer for forming a laminate separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention contains the above-described composition. The layer is, for example, a porous layer.

[0082] The air permeability of the layer is preferably 400 s / 100 mL or less, and more preferably 200 s / 100 mL or less. If the air permeability of the layer is within the above range, it can be said that the laminated separator has sufficient ion permeability. In this specification, the air permeability represents a value measured using an Oken air permeability tester in accordance with JIS P8117.

[0083] For example, when the laminated separator consists only of a polyolefin porous film and the layer, the air permeability of the layer is calculated as YX, where X is the air permeability of the polyolefin porous film and Y is the air permeability of the laminated separator.

[0084] The weight per unit area of ​​the layer, i.e., the basis weight, is 0.6 to 2.5 g / m from the viewpoint of controlling the air permeability within a suitable range. 2 It is preferable that the density is 0.8 to 2.0 g / m 2 It is more preferable that:

[0085] The upper limit of the thickness of the layer is preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less, and the lower limit of the thickness of the layer is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably 0.6 μm or more.

[0086] [3. Laminated separator for non-aqueous electrolyte secondary batteries] A laminate separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention comprises a polyolefin porous film and a layer for forming the laminate separator for a non-aqueous electrolyte secondary battery laminated on one or both sides of the polyolefin porous film. That is, the laminate separator includes a polyolefin porous film and the layer for forming the laminate separator for a non-aqueous electrolyte secondary battery laminated on one or both sides of the polyolefin porous film. Hereinafter, the polyolefin porous film will also be simply referred to as a "porous film." The layer for forming the laminate separator for a non-aqueous electrolyte secondary battery is also a layer containing the above-mentioned composition.

[0087] The air permeability of the laminate separator is preferably 500 s / 100 mL or less, and more preferably 300 s / 100 mL or less. If the air permeability of the laminate separator is within the above range, it can be said that the laminate separator has sufficient ion permeability.

[0088] The layer containing the composition may be provided on one side of the porous film or on both sides of the porous film, and the layer containing the composition and the layer containing the composition provided on both sides of the porous film may have the same or different film thickness, basis weight, and porosity.

[0089] <3-1. Porous film> The porous film has many interconnected pores within it, allowing gases and liquids to pass from one side to the other. The porous film can serve as a substrate for a laminated separator. The porous film can melt when the battery generates heat, rendering the laminated separator porous, thereby imparting a shutdown function to the laminated separator.

[0090] Here, the term "polyolefin porous film" refers to a porous film whose main component is a polyolefin resin. The term "mainly composed of a polyolefin resin" means that the proportion of the polyolefin resin in the porous film is 50% by volume or more, preferably 90% by volume or more, and more preferably 95% by volume or more of the total material constituting the porous film. This means that

[0091] The polyolefin resin, which is the main component of the porous film, is not particularly limited, and examples thereof include homopolymers and copolymers obtained by polymerizing monomers such as thermoplastic resins, such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, and / or 1-hexene. Homopolymers include polyethylene, polypropylene, and polybutene, while copolymers include ethylene-propylene copolymers. The porous film may be a layer containing one of these polyolefin resins alone, or a layer containing two or more of these polyolefin resins. Among these, polyethylene is more preferred because it can prevent (shut down) excessive current flow at lower temperatures, and high-molecular-weight polyethylene composed primarily of ethylene is particularly preferred. The polyolefin porous film may contain components other than polyolefins as long as their functionality is not impaired.

[0092] Examples of polyethylene include low-density polyethylene, high-density polyethylene, linear polyethylene (ethylene-α-olefin copolymer), and ultra-high molecular weight polyethylene. Among these, ultra-high molecular weight polyethylene is more preferred, and the weight-average molecular weight is 5×10 5 ~15×10 6 It is particularly preferable that the polyolefin resin contains a high molecular weight component having a weight average molecular weight of 1,000,000 or more, since this improves the strength of the porous film and the laminate separator.

[0093] The porous film may have a multilayer structure consisting of two or more layers. An example of a porous film with a multilayer structure is one in which a layer mainly composed of polyethylene and a layer mainly composed of polypropylene are laminated together. The number of layers is not particularly limited, and the film may be two layers composed of polyethylene and polypropylene, or three layers composed of a combination of polyethylene and polypropylene. By using a multilayer structure of polyethylene and polypropylene, it is possible to achieve both shutdown properties and heat resistance.

[0094] The porous film may have a crosslinked structure. The crosslinked structure can be introduced, for example, by using a silane-modified polyolefin. A porous film having a crosslinked structure has excellent heat resistance, and therefore, by combining it with a layer containing the composition, the heat resistance of the laminated separator can be further improved. The crosslinked structure may be formed between the porous film and the layer containing the composition.

[0095] The thickness of the porous film is preferably 3 to 20 μm, more preferably 4 to 15 μm, and even more preferably 4.5 to 15 μm. If the thickness is 3 μm or more, the strength of the laminated separator can be ensured. Furthermore, if the thickness is 3 μm or more, the required functions (shutdown function, etc.) can be sufficiently obtained. If the thickness is 20 μm or less, a thin laminated separator can be obtained.

[0096] The pore size of the porous film is preferably 0.1 μm or less, and more preferably 0.06 μm or less, which allows for sufficient ion permeability and better prevents particles constituting the electrode from entering.

[0097] The weight per unit area of ​​the porous film, i.e., the weight per unit area, is usually 2 to 20 g / m2 so as to increase the weight energy density and volume energy density of the battery. 2 It is preferable that the density is 2.5 to 12 g / m 2 It is more preferable that:

[0098] The air permeability of the porous film is preferably 30 to 500 s / 100 mL, and more preferably 50 to 300 s / 100 mL. Sufficient ion permeability can be obtained.

[0099] The porosity of the porous film is preferably 20 to 80% by volume, more preferably 30 to 75% by volume, which increases the amount of electrolyte retained and reliably prevents excessive current from flowing even at low temperatures.

[0100] The method for producing a porous film is not particularly limited and may be a known method, such as a method described in Japanese Patent No. 5476844 in which a filler is added to a thermoplastic resin, a film is formed, and then the filler is removed.

[0101] Specifically, for example, when the porous film is formed from a polyolefin resin containing ultra-high molecular weight polyethylene and a low molecular weight polyolefin having a weight average molecular weight of 10,000 or less, it is preferably produced by a method including the following steps (1) to (4) from the viewpoint of production costs: (1) A step of kneading 100 parts by weight of ultra-high molecular weight polyethylene, 5 to 200 parts by weight of a low-molecular weight polyolefin having a weight-average molecular weight of 10,000 or less, and 100 to 400 parts by weight of an inorganic filler such as calcium carbonate to obtain a polyolefin-based resin composition; (2) forming a sheet from the polyolefin resin composition; (3) a step of removing the inorganic filler from the sheet obtained in step (2); (4) A step of stretching the sheet obtained in step (3). In addition, the methods described in the above-mentioned patent documents may also be used.

[0102] <3-2. Another functional layer> The laminate separator may include a functional layer different from the porous film and the layer containing the composition, as needed, without impairing the objectives of the present invention. Examples of such functional layers include an adhesive layer, a heat-resistant porous layer different from the layer containing the composition, a slip layer intended to improve the slippage of the separator, a layer containing organic particles such as polyolefins intended to provide shutdown properties, an antistatic layer, a protective layer, and other known porous layers. For example, the laminate separator may include, in addition to the porous film and the layer containing the composition, a functional layer different from the layer containing the composition, as needed, without impairing the objectives of the present invention. A heat-resistant porous layer different from the layer containing the composition means that the type of resin and filler, the amount of filler, etc., differ from those of the layer containing the composition. When the functional layer is a heat-resistant porous layer different from the layer containing the composition, the resin, filler, and filler amount exemplified for the composition can be applied to the functional layer. The slip layer may be a layer containing an antiblocking agent or a layer containing a filler, and the slippage of the separator can be improved by providing surface irregularities.

[0103] The other functional layer may be provided on one or both sides of the laminated separator. When the laminated separator has layers containing the composition on both sides of a porous film, the other functional layer may be provided on the layers containing the composition on both sides, or on the layer containing the composition on one side. When the laminated separator has a layer containing the composition on only one side of a porous film, the other functional layer may be provided on the layer containing the composition, or on the side of the porous film that does not have the layer containing the composition. The other functional layer may be provided in the outermost layer of the laminated separator.

[0104] For example, the laminated separator further includes an adhesive layer in addition to the porous film and the layer containing the composition. In this specification, the adhesive layer means a layer having adhesive properties. The adhesive layer may be provided on the surface of the laminated separator that contacts the electrode. Examples of components that contribute to adhesive properties contained in the adhesive layer include acrylic resins and PVDF-based resins. Examples of acrylic resins include those described in paragraphs

[0072] to

[0088] of JP 2024-006988 A. The PVDF-based resins described in paragraphs

[0017] to

[0022] of JP 2017-168419 A can be used. Examples of the PVDF-based resin include those described in paragraphs

[0017] to

[0022] . The acrylic resin and the PVDF-based resin can be used alone or in combination. The adhesive layer may further contain a filler in addition to the component that contributes to adhesiveness. The filler may be the same as the filler added to the composition. The state of the adhesive layer is not particularly limited; the component that contributes to adhesiveness may be present in a particulate form or as a homogeneous coating layer. The adhesive layer may also be present in a dotted or striped form by pattern coating. By providing the adhesive layer, the laminated separator is fixed to the electrode via the adhesive layer, thereby improving the handleability and heat resistance of the electrode laminate. Furthermore, by forming the adhesive layer in a particulate, dotted, or striped form, a decrease in the ion permeability of the laminated separator can be suppressed.

[0105] <3-3. Manufacturing method of layers and manufacturing method of laminated separator> For example, the laminated separator can be produced by forming a layer on one or both sides of the porous film using a coating liquid in which the components constituting the composition are dissolved or dispersed in a solvent. Examples of methods for forming the coating liquid include mechanical stirring, ultrasonic dispersion, high-pressure dispersion, and media dispersion. Examples of solvents that can be used include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide. The solvent can also be considered a dispersion medium that disperses the components constituting the composition.

[0106] The method for producing the laminate separator includes, for example, preparing the coating liquid, applying the coating liquid to a porous film, and drying the coating liquid to form a layer containing the composition on the porous film. In the method for producing the layer, the object to which the coating liquid is applied is not limited to a porous film, and other films, positive electrodes, negative electrodes, etc. may also be used.

[0107] The coating liquid can be applied to the porous film by any known coating method such as a knife, blade, bar, gravure, or die.

[0108] The solvent is generally removed by drying. Examples of drying methods include natural drying, air drying, heat drying, and reduced pressure drying, but any method may be used as long as it can sufficiently remove the solvent. Alternatively, the solvent contained in the paint may be replaced with another solvent before drying. Specific examples of methods for replacing the solvent with another solvent before removal include replacing the solvent with a low-boiling point poor solvent such as water, alcohol, or acetone, precipitating the solvent, and then drying the resulting mixture.

[0109] 4. Non-aqueous electrolyte secondary battery components and non-aqueous electrolyte secondary batteries A nonaqueous electrolyte secondary battery member according to one embodiment of the present invention includes a positive electrode, the above-described laminated separator, and a negative electrode arranged in this order. A nonaqueous electrolyte secondary battery according to one embodiment of the present invention also includes the above-described laminated separator.

[0110] The nonaqueous electrolyte secondary battery typically has a structure in which a negative electrode and a positive electrode face each other with the laminate separator interposed therebetween. In the nonaqueous electrolyte secondary battery, a battery element in which the structure is impregnated with an electrolyte is sealed in an exterior material. For example, the nonaqueous electrolyte secondary battery is a lithium ion secondary battery that generates electromotive force by doping and undoping lithium ions.

[0111] <Positive electrode> The positive electrode may be, for example, a positive electrode in which an active material layer containing a positive electrode active material and a binder is formed on a current collector. A positive electrode sheet having the above structure can be used. The active material layer may further contain a conductive agent.

[0112] The positive electrode active material may be, for example, a material that can be doped and dedoped with lithium ions.

[0113] Examples of such materials include lithium composite oxides containing at least one transition metal, such as V, Ti, Cr, Mn, Fe, Co, Ni, and Cu. Examples of lithium composite oxides include lithium composite oxides having a layered structure, lithium composite oxides having a spinel structure, and solid-solution lithium-containing transition metal oxides composed of lithium composite oxides having both a layered structure and a spinel structure. Other examples include lithium cobalt composite oxides and lithium nickel composite oxides. Furthermore, examples of these lithium composite oxides in which a portion of the transition metal atoms that constitute the main component of the lithium composite oxides has been substituted with other elements, such as Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mg, Ca, Ga, Zr, Si, Nb, Mo, Sn, and W, are also included.

[0114] Examples of the lithium composite oxide in which a portion of the transition metal atoms that constitute the main component of the lithium composite oxide are substituted with other elements include a lithium cobalt composite oxide having a layered structure represented by the following formula (3), a lithium nickel composite oxide represented by the following formula (4), a lithium manganese composite oxide having a spinel structure represented by the following formula (5), and a solid solution lithium-containing transition metal oxide represented by the following formula (6).

[0115] Li x (Co 1-a M 1 a ) 1-x ]O2...Equation (3) (In formula (3), M 1is at least one metal selected from the group consisting of Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W, and satisfies -0.1 ≦ x ≦ 0.30, 0 ≦ a ≦ 0.5.) Li[Li y (Ni 1-b M 2 b ) 1-y O2 ··· Formula (4) (In Formula (4), M 2 is at least one metal selected from the group consisting of Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W, and satisfies -0.1 ≦ y ≦ 0.30, 0 ≦ b ≦ 0.5.) Li z Mn 2-c M 3 c O4 ··· Formula (5)​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​0.8 Co 0.15 Al 0.05 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.33 Co 0.33 Mn 0.33 O2, LiMn2O4, LiMn 1.5 Ni 0.5 O4, LiMn 1.5 Fe 0.5 O4, LiCoMnO4, Li 1.21 Ni 0.20 Mn 0.59 O2, Li 1.22 Ni 0.20 Mn 0.58 O2, Li 1.22 Ni 0.15 Co 0.10 Mn 0.53 O2, Li 1.07 Ni 0.35 Co 0.08 Mn 0.50 O2, Li 1.07 Ni 0.36 Co 0.08 Mn 0.49 Examples include O2.

[0116] Lithium composite oxides other than those represented by formulas (3) to (6) are also preferred. Such lithium composite oxides can be preferably used as the positive electrode active material. Examples of such lithium composite oxides include LiNiVO4, LiV3O6, and Li 1.2 Fe 0.4 Mn 0.4 Examples include O2.

[0117] Materials other than lithium composite oxides that can be preferably used as the positive electrode active material include, for example, phosphates having an olivine structure, such as those represented by the following formula (7):

[0118] Li v (M 6 f M7 g M 8 h M 9 i ) j PO4...Equation (7) (In formula (7), M 6 is Mn, Co, or Ni, and M 7 is Ti, V, Cr, Mn, Fe, Co, Ni, Zr, Nb, or Mo, and M 8 is a transition metal or main group element, optionally excluding elements of groups VIA and VIIA, and M 9 is a transition metal or a main group element, optionally excluding elements of Groups VIA and VIIA, and satisfies 1.2 ≥ a ≥ 0.9, 1 ≥ b ≥ 0.6, 0.4 ≥ c ≥ 0, 0.2 ≥ d ≥ 0, 0.2 ≥ e ≥ 0, 1.2 ≥ f ≥ 0.9. The positive electrode active material preferably has a coating layer on the surface of the lithium metal composite oxide particles constituting the positive electrode active material. Examples of materials constituting the coating layer include metal composite oxides, metal salts, boron-containing compounds, nitrogen-containing compounds, silicon-containing compounds, and sulfur-containing compounds, and among these, metal composite oxides are preferably used.

[0119] The metal composite oxide is preferably an oxide having lithium ion conductivity. Examples of such metal composite oxides include metal composite oxides of Li and at least one element selected from the group consisting of Nb, Ge, Si, P, Al, W, Ta, Ti, S, Zr, Zn, V, and B. When the positive electrode active material has a coating layer, the coating layer suppresses side reactions at the interface between the positive electrode active material and the electrolyte under high voltage, thereby achieving a longer life for the resulting secondary battery. Furthermore, the formation of a high-resistance layer at the interface between the positive electrode active material and the electrolyte is suppressed, thereby achieving a higher output for the resulting secondary battery.

[0120] Examples of the conductive agent include carbonaceous materials such as natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fiber, and baked organic polymer compounds.

[0121] Examples of the binder include polyvinylidene fluoride, vinylidene fluoride copolymers, polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, ethylene-tetrafluoroethylene copolymers, vinylidene fluoride-tetrafluoroethylene copolymers, vinylidene fluoride-trifluoroethylene copolymers, vinylidene fluoride-trichloroethylene copolymers, vinylidene fluoride-vinyl fluoride copolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymers, thermoplastic resins such as thermoplastic polyimide, polyethylene, and polypropylene, acrylic resins, and styrene-butadiene rubber. The binder also functions as a thickener.

[0122] Examples of the positive electrode current collector include conductive materials such as Al, Ni, stainless steel, etc. Among them, Al is more preferable because it can be easily processed into a thin film and is inexpensive.

[0123] Examples of methods for producing a sheet-like positive electrode include a method in which a positive electrode active material, a conductive agent, and a binder that constitute a positive electrode mixture are pressure-molded on a positive electrode current collector; and a method in which a positive electrode active material, a conductive agent, and a binder are made into a paste using an appropriate organic solvent to obtain a positive electrode mixture, and then the positive electrode mixture is applied to a positive electrode current collector and dried to obtain a sheet-like positive electrode mixture, which is then pressed to adhere to the positive electrode current collector.

[0124] <Negative electrode> The negative electrode may be, for example, a negative electrode sheet having a structure in which an active material layer containing a negative electrode active material and a binder is formed on a current collector. The active material layer may further contain a conductive agent.

[0125] Examples of the negative electrode active material include carbon materials, chalcogen compounds (oxides, sulfides, etc.), nitrides, metals, and alloys that can be doped and dedoped with lithium ions at a lower potential than the positive electrode.

[0126] Examples of carbon materials that can be used as the negative electrode active material include graphite such as natural graphite and artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fiber, and fired organic polymer compounds.

[0127] Examples of oxides that can be used as the negative electrode active material include oxides represented by the formula SiO x (where x is a positive real number); oxides of silicon such as TiO2 and TiO with the formula TiO x (where x is a positive real number); oxides of titanium represented by the formula V such as V2O5 and VO2 x O y (where x and y are positive real numbers); oxides of vanadium such as Fe3O4, Fe2O3, and FeO, with the formula Fe x O y (where x and y are positive real numbers); oxides of iron, such as SnO2 and SnO, with the formula SnO x (where x is a positive real number); tin oxides such as WO3 and WO2, with the general formula WO x (where x is a positive real number) is the oxide of tungsten; Li4Ti5O 12 and composite metal oxides containing lithium, such as LiVO2, and titanium or vanadium;

[0128] Examples of sulfides that can be used as the negative electrode active material include those represented by the formula Ti, such as Ti2S3, TiS2, and TiS. x S y (where x and y are positive real numbers); titanium sulfides such as V3S4, VS2, and VS, with the formula VS x (where x is a positive real number); vanadium sulfides such as Fe3S4, FeS2, and FeS, with the formula Fe x S y (where x and y are positive real numbers); iron sulfides such as Mo2S3 and MoS2 with the formula Mo x S y (where x and y are positive real numbers) Molybdenum sulfides such as SnS2 and SnS with the formula SnS xSulfide of tin represented by (where x is a positive real number); Sulfide of tungsten such as WS2, formula WS x Sulfide of tungsten represented by (where x is a positive real number); Sulfide of antimony such as Sb2S3, formula Sb x S y Sulfide of antimony represented by (where x and y are positive real numbers); Sulfide of selenium such as Se5S3, SeS2, SeS, formula Se x S y Sulfide of selenium represented by (where x and y are positive real numbers); can be mentioned.

[0129] As nitrides that can be used as negative electrode active materials, for example, Li3N, Li 3-x A x Lithium-containing nitrides such as N (where A is either one or both of Ni and Co, and 0 < x < 3) can be mentioned.

[0130] These carbon materials, oxides, sulfides, and nitrides may be used alone or in combination of two or more. Also, these carbon materials, oxides, sulfides, and nitrides may be either crystalline or amorphous. These carbon materials, oxides, sulfides, and nitrides are mainly supported on a negative electrode current collector and used as an electrode.

[0131] Also, as metals that can be used as negative electrode active materials, lithium metal, silicon metal, tin metal, etc. can be mentioned.

[0132] Also, composite materials containing Si or Sn as the first constituent element and, in addition, the second and third constituent elements can be mentioned. The second constituent element is, for example, at least one of cobalt, iron, magnesium, titanium, vanadium, chromium, manganese, nickel, copper, zinc, gallium, and zirconium. The third constituent element is, for example, at least one of boron, carbon, aluminum, and phosphorus.

[0133] Particularly, since high battery capacity and excellent battery characteristics can be obtained, as the metal material, silicon or tin alone (which may contain trace amounts of impurities), SiO​v (0 <v≦2)、SnO w (0≦w≦2), Si—Co—C composite material, Si—Ni—C composite material, Sn—Co—C composite material, and Sn—Ni—C composite material are preferred.

[0134] Examples of the negative electrode current collector include Cu, Ni, stainless steel, etc. Among them, Cu is more preferable, particularly in lithium ion secondary batteries, because it is difficult to form an alloy with lithium and it can be easily processed into a thin film.

[0135] Examples of methods for producing a sheet-like negative electrode include a method of press-molding a negative electrode active material that will become a negative electrode mixture onto a negative electrode current collector, a method of forming a negative electrode active material into a paste using an appropriate organic solvent to obtain a negative electrode mixture, applying the negative electrode mixture to a negative electrode current collector, drying the mixture, and then pressing the resulting sheet-like negative electrode mixture to adhere it to the negative electrode current collector. The paste preferably contains the conductive agent and the binder.

[0136] <Nonaqueous electrolyte> The non-aqueous electrolyte may be, for example, a non-aqueous electrolyte prepared by dissolving a lithium salt in an organic solvent. Examples of lithium salts include LiClO4, LiPF6, LiAsF6, LiSbF6, LiBF4, LiSO3F, LiCF3SO3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(COCF3), Li(C4F9SO3), LiC(SO2CF3)3, and Li2B 10 Cl 10 , LiBOB (here, BOB stands for bis(oxalato)borate), lithium salts of lower aliphatic carboxylic acids, LiAlCl4, etc. These may be used alone or as a mixture of two or more. Among them, it is preferable to use a lithium salt containing at least one selected from the group consisting of fluorine-containing LiPF6, LiAsF6, LiSbF6, LiBF4, LiSO3F, LiCF3SO3, LiN(SO2CF3)2, and LiC(SO2CF3)3.

[0137] Examples of organic solvents include carbonates such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 4-trifluoromethyl-1,3-dioxolan-2-one, and 1,2-di(methoxycarbonyloxy)ethane; 1,2-dimethoxyethane, 1,3-dimethoxypropane, pentafluoropropyl methyl ether, 2,2,3,3-tetrafluoropropyl difluoromethyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran. esters such as methyl formate, methyl acetate, and γ-butyrolactone; nitriles such as acetonitrile and butyronitrile; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; carbamates such as 3-methyl-2-oxazolidone; sulfur-containing compounds such as sulfolane, dimethyl sulfoxide, and 1,3-propane sultone; or organic solvents such as these with a fluoro group introduced therein (organic solvents in which one or more hydrogen atoms have been replaced with fluorine atoms).

[0138] The organic solvent is preferably used as a mixed solvent by mixing two or more kinds. Among them, a mixed solvent containing carbonates is preferred, and a mixed solvent of a cyclic carbonate and an acyclic carbonate and a mixed solvent of a cyclic carbonate and an ether are more preferred. As a mixed solvent of a cyclic carbonate and an acyclic carbonate, a mixed solvent containing ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate is preferred. Such a mixed solvent A nonaqueous electrolyte using a mixed solvent has the advantages of a wide operating temperature range, being resistant to deterioration even when used at high voltages and for long periods of time, and being resistant to decomposition even when a graphite material such as natural graphite or artificial graphite is used as the active material of the negative electrode.

[0139] Furthermore, it is preferable to use a nonaqueous electrolyte solution containing a fluorine-containing lithium salt such as LiPF6 and an organic solvent having a fluorine substituent, as this increases the safety of the resulting nonaqueous electrolyte secondary battery. A mixed solvent containing dimethyl carbonate and an ether having a fluorine substituent, such as pentafluoropropyl methyl ether or 2,2,3,3-tetrafluoropropyl difluoromethyl ether, is more preferable, as it has a high capacity retention rate even when discharged at a high voltage.

[0140] <Members for non-aqueous electrolyte secondary batteries and methods for manufacturing non-aqueous electrolyte secondary batteries> As a method for producing a member for a non-aqueous electrolyte secondary battery, for example, there can be mentioned a method in which a positive electrode, a laminated separator for a non-aqueous electrolyte secondary battery according to one embodiment of the present invention, and a negative electrode are arranged in this order.

[0141] The following method can be used to manufacture a nonaqueous electrolyte secondary battery. First, a nonaqueous electrolyte secondary battery component is placed in a container that will serve as the housing of the nonaqueous electrolyte secondary battery. Next, the container is filled with a nonaqueous electrolyte, and then the container is sealed while reducing the pressure. This completes the manufacture of a nonaqueous electrolyte secondary battery.

[0142] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0143] An embodiment of the present invention may include the following features. <1> A composition for forming a laminate separator for a non-aqueous electrolyte secondary battery, comprising: a resin having an amide bond; the resin having an amide bond comprises a component eluted in NMP; and the content of the component eluted in NMP is more than 25.0 wt % and not more than 45.0 wt % relative to the total weight of the resin having an amide bond. <2> The resin is an aramid resin. <1> The composition described in <3> The aramid resin is Block A mainly composed of a unit represented by the following formula (1), -(NH-Ar 1 -NHCO-Ar 2 -CO)- Formula (1) Block B mainly composed of a unit represented by the following formula (2), -(NH-Ar 3 -NHCO-Ar 4 -CO)- Formula (2) and a block copolymer having the formula: <2> The composition described in (In formula (1) and formula (2), Ar 1 , Ar 2 , Ar 3 and Ar 4 may be different for each unit, Ar 1 , Ar 2 , Ar 3 and Ar 4 are each independently a divalent group having one or more aromatic rings, All Ar 1 More than 50% of these have a structure in which two aromatic rings are connected by a sulfonyl bond. All Ar 3 Of these, 50% or less have a structure in which two aromatic rings are connected by a sulfonyl bond, All Ar 1 and Ar 3 Of these, 10-70% have a structure in which two aromatic rings are linked by a sulfonyl bond. <4> The composition further contains a filler, and the content of the filler is 20 to 90% by weight based on the total amount of the resin and the filler. <1> ~ <3> The composition according to any one of the preceding claims. <5> <1> ~ <4> 10. A layer for forming a laminate separator for a non-aqueous electrolyte secondary battery, comprising the composition according to any one of 1 to 9. <6> A porous layer, <5> 2. A layer for forming a laminate separator for a non-aqueous electrolyte secondary battery according to claim 1. <7> On one or both sides of the polyolefin porous film, <5> or <6> 10. A laminate separator for a non-aqueous electrolyte secondary battery, comprising a laminated layer for forming a laminate separator for a non-aqueous electrolyte secondary battery according to claim 19. <8> An adhesive layer is further provided in addition to the polyolefin porous film and the layer for forming the laminate separator for a non-aqueous electrolyte secondary battery. <7> 2. The laminate separator for a non-aqueous electrolyte secondary battery according to claim 1. <9> A positive electrode and <7> or <8> 10. A member for a non-aqueous electrolyte secondary battery, comprising the laminate separator for a non-aqueous electrolyte secondary battery according to claim 1, and a negative electrode, arranged in this order. <10> <7> or <8> A non-aqueous electrolyte secondary battery comprising the laminate separator for a non-aqueous electrolyte secondary battery according to claim 1. [Example]

[0144] An embodiment of the present invention will now be described.

[0145] EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0146] [Methods for measuring various physical properties] In the examples and comparative examples described below, the various physical properties were measured by the following methods.

[0147] [Content of components eluted in NMP] 0.5 L of ion-exchanged water was placed in a flask. 50 mL of the aramid polymerization liquid obtained in the Examples and Comparative Examples described below was measured out. The 50 mL of the measured aramid polymerization liquid was then added to the flask to precipitate an aramid resin. The solution from which the aramid resin had been precipitated was filtered once, and then 100 mL of ion-exchanged water was added to the resulting precipitate and filtered again. That is, filtration was performed twice. As a result, 3.50 g of aramid resin was obtained.

[0148] 0.10 g was weighed out from this aramid resin. The weighed 0.10 g of aramid resin was immersed in 100 mL of NMP in a vial. After appropriate stirring, the extract was filtered after 5 days through a PTFE membrane filter with a pore size of 0.45 μm to obtain filtrate A. Meanwhile, 1 g of the aramid polymerization solution was diluted with 69 g of NMP so as to contain the same weight of aramid resin as the aramid resin immersed in NMP, and filtered through a PTFE membrane filter with a pore size of 0.45 μm to obtain filtrate B. Filtrate A and filtrate B were each subjected to size exclusion chromatography (SEC) analysis under the following conditions. The instrument used was a Shimadzu LC-20A equivalent, and two Tosoh TSK-GEL SUPER AWM-H columns connected together. The eluent was NMP containing 5 wt% CaCl2. The flow rate was 0.4 mL / min, the column temperature was 40°C, and detection was at UV 310 nm. The "area value of the aramid resin immersion solution" and the "area value of the reference solution" were calculated from the chromatograms obtained from filtrate A and filtrate B, respectively. The "area value of the aramid resin immersion solution" was the area value in the chromatogram obtained using filtrate A, and the "area value of the reference solution" was the area value in the chromatogram obtained using filtrate B.

[0149] Using the "area value of the aramid resin immersion solution" and the "area value of the reference solution" obtained by the above operations, the content of the components eluted into NMP relative to the total weight of the aramid resin was calculated according to the following formula (8). The content of components eluted into NMP relative to the total weight of the aramid resin [wt%] = area value of aramid immersion solution / area value of reference solution × 100 (8) [Increase in air permeability] The air permeability of the polyethylene porous film and the laminated separator cut into a size of 60 mm x 60 mm was measured in accordance with JIS P8117 using a digital Oken-type air permeability tester EGO1 manufactured by Asahi Seiko Co., Ltd. The numerical value obtained by subtracting the air permeability of the polyethylene porous film from the air permeability of the obtained laminated separator was taken as the increase in air permeability due to the lamination of the porous layer.

[0150] [150℃ heating shape retention rate] The laminated separators obtained in the Examples and Comparative Examples described below were cut into 8 cm x 8 cm squares. 6 cm square lines were drawn in both the MD and TD directions on the inside of the outer edge of the 8 cm square of the cut-out square laminated separator to obtain samples for measuring heat resistance. The samples were sandwiched between papers and placed in an oven heated to 150°C. After 1 hour, the samples were removed from the oven, and the lengths of the drawn lines in the MD and TD directions were measured using digital calipers. The measured length D of the line drawn in the MD MD [cm], and the length of the line drawn in the TD direction D TD Using the measured values ​​in units of [cm], the "150°C MD shape retention rate" and the "150°C TD shape retention rate" of the laminated separator were calculated according to the following formulas (9) and (10). 150℃MD shape retention rate [%]=D MD / 6×100···(9) 150℃TD shape retention rate [%]=D TD / 6×100···(10) The smaller of the 150°C MD shape retention rate [%] and the 150°C TD shape retention rate [%] was adopted as the 150°C shape retention rate [%] of the laminated separator.

[0151] [Weight per unit area] A square sample of 8 cm x 8 cm was cut out from the porous film. The weight of this sample was measured and designated as W1 [g]. The basis weight of the porous film was calculated according to the following formula (11). Weight of porous film [g / m 2 ]=W1[g] / (0.08×0.08)···(11) An 8 cm x 8 cm square sample was cut out from the laminated separator. The weight of this sample was measured and designated as W2 [g]. The basis weight of the laminated separator was calculated according to the following formula (12). Weight of laminated separator [g / m 2 ]=W2[g] / (0.08×0.08)···(12) The weight per unit area of ​​the porous layer was calculated by subtracting the weight per unit area of ​​the porous film from the weight per unit area of ​​the laminated separator.

[0152] [Production Example 1] Coating liquid (1) was prepared according to the following procedure: The aramid resin contained in coating liquid (1) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4241 g of NMP was charged into the flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in such a manner that the moisture content of the calcium chloride solution would be 450 ppm. The calcium chloride used was previously dried in a vacuum at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.76 g of 4,4'-diaminodibenzofuran was added. Phenyl sulfone (DDS) was added and allowed to dissolve completely. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 115.67 g of terephthalic acid dichloride (TPC) was added in three portions. The reaction was carried out for 1 hour to synthesize Block A1 consisting of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 1.002. 5. 61.74 g of paraphenylenediamine (PPD) was added to the flask and allowed to dissolve completely over 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 113.08 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing the poly(paraphenylene terephthalamide) block B1 to extend on both sides of the block A1. The molar ratio of PPD to TPC was 1.025. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (A) was obtained. In the block copolymer contained in aramid polymerization liquid (A), block A1 accounts for 50% of the entire molecule, and block B1 accounts for the remaining 50% of the entire molecule. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (A) and mixed in such a way that the weight ratio of aramid resin to alumina was 3:1. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixture obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare a slurry coating solution (1).

[0153] [Production Example 2] A slurry coating liquid (2) was prepared in the same manner as in Production Example 1, except that the weight ratio of the aramid resin to the alumina in step 8 was changed to 4:1.

[0154] [Production Example 3] Coating liquid (3) was prepared according to the following procedure: The aramid resin contained in coating liquid (3) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4241 g of NMP was charged into the flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in such a manner that the moisture content of the calcium chloride solution would be 450 ppm. The calcium chloride used was previously dried in a vacuum at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.61g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 116.13 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize Block A2, which consisted of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 0.997. 5. 61.67g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 112.96 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing the poly(paraphenylene terephthalamide) block B2 to extend on both sides of the block A2. The molar ratio of PPD to TPC was 1.025. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. Aramid polymerization solution (B) was obtained. The block copolymer contained in the aramid polymerization solution (B) is composed of block A2 accounting for 50% of the entire molecule, and block B2 accounting for the remaining 50% of the entire molecule. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (B) and mixed so that the weight ratio of aramid resin to alumina was 2:1. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixture obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare a slurry coating solution (3).

[0155] [Production Example 4] A slurry coating liquid (4) was prepared in the same manner as in Production Example 3, except that the weight ratio of the aramid resin to the alumina in step 8 was changed to 3:1.

[0156] [Production Example 5] Coating liquid (5) was prepared according to the following procedure: The aramid resin contained in coating liquid (5) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4241 g of NMP was charged into the flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in such a manner that the moisture content of the calcium chloride solution would be 450 ppm. The calcium chloride used was previously dried in a vacuum at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.70 g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 115.86 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize block A3 consisting of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 1.00. 5. 61.71 g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 113.03 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing block B3 (poly(paraphenylene terephthalamide)) to extend on both sides of block A3. The molar ratio of PPD to TPC was 1.025. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (C) was obtained. In the block copolymer contained in aramid polymerization liquid (C), block A3 accounted for 50% of the entire molecule, and block B3 accounted for the remaining 50% of the entire molecule. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (C) and mixed. At this time, alumina was added so that the weight ratio of aramid resin to alumina was 3:1. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixture obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare a slurry coating solution (5).

[0157] [Production Example 6] A slurry coating liquid (6) was prepared in the same manner as in Production Example 5, except that the weight ratio of the aramid resin to the alumina in step 8 was changed to 4:1.

[0158] [Production Example 7] Coating liquid (7) was prepared according to the following procedure: The aramid resin contained in coating liquid (7) is a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4234 g of NMP was charged into the flask. 325.5 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in a manner calculated to give a moisture content of 450 ppm. The calcium chloride used was previously dried in a vacuum at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 94.01 g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 77.25 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize block A4 consisting of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 0.995. 5. 95.53 g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 173.29 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing block B4 (poly(paraphenylene terephthalamide)) to extend on both sides of block A4. The molar ratio of PPD to TPC was 1.035. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, an aramid polymerization liquid (D) was obtained. In the block copolymer contained in the aramid polymerization liquid (D), block A4 accounted for 30% of the entire molecule, and block B4 accounted for the remaining 70% of the entire molecule. The aramid polymerization liquid (D) contained an aramid resin containing the block copolymer. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (D) and mixed in such a way that the weight ratio of the aramid resin containing the block copolymer to alumina was 1:1. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixture obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare a slurry coating solution (7).

[0159] [Comparative Production Example 1] Coating liquid (8) was prepared according to the following procedure: The aramid resin contained in coating liquid (8) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4241 g of NMP was charged into the flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in such a manner that the moisture content of the calcium chloride solution would be 800 ppm. The calcium chloride used was previously vacuum-dried at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.70 g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, A total of 116.30 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize Block A5, which consisted of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 0.995. 5. 61.71 g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 113.03 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing block B5 (poly(paraphenylene terephthalamide)) to extend on both sides of block A5. The molar ratio of PPD to TPC was 1.025. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (E) was obtained. In the block copolymer contained in aramid polymerization liquid (E), block A5 accounted for 50% of the entire molecule, and block B5 accounted for the remaining 50% of the entire molecule. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (E) and mixed so that the weight ratio of aramid resin to alumina was 3:1. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixed solution obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized solution was degassed under reduced pressure to prepare a slurry coating solution (8).

[0160] [Comparative Production Example 2] Coating liquid (9) was prepared according to the following procedure: The aramid resin contained in coating liquid (9) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4202 g of NMP was charged into a flask. 365.9 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (8.0 wt%). Water was added to the calcium chloride solution in a manner calculated to give a moisture content of 300 ppm. The calcium chloride used was previously vacuum-dried at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.97 g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 16°C. While maintaining the temperature of the polymerization system at 16±2°C, a total of 114.25 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize Block A6, which consisted of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 1.016. 5. 61.83 g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 18±2°C, a total of 114.03 g of TPC was added in three portions. The reaction was continued for 1.5 hours, allowing block B6 (poly(paraphenylene terephthalamide)) to extend on both sides of block A6. The molar ratio of PPD to TPC was 1.018. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (F) was obtained. In the block copolymer contained in aramid polymerization liquid (F), block A6 accounted for 50% of the entire molecule, and block B6 accounted for the remaining 50% of the entire molecule. 8. Alumina (average particle size: 13 nm) was added to the aramid polymerization liquid (F) and mixed so that the weight ratio of aramid resin to alumina was 1:1. 9. NMP as a diluent and calcium carbonate as a neutralizer were added to the mixture obtained in step 8 so that the solid content was 4% by weight. The "solid content" here refers to the content of aramid resin and alumina. The solution was stirred for 20 minutes to dilute and neutralize it. This neutralized solution was The mixture was degassed under reduced pressure to prepare a coating liquid slurry (9).

[0161] Comparative Production Example 3 A slurry coating liquid (10) was prepared in the same manner as in Comparative Production Example 1, except that in step 8 the weight ratio of aramid resin to alumina was changed to 3:2.

[0162] Comparative Production Example 4 A slurry coating liquid (11) was prepared in the same manner as in Comparative Production Example 1, except that in step 8 the weight ratio of aramid resin to alumina was changed to 7:3.

[0163] Comparative Example 5 A slurry coating liquid (12) was prepared in the same manner as in Comparative Production Example 1, except that in step 8 the weight ratio of aramid resin to alumina was changed to 4:1.

[0164] [Production Example 8] Coating liquid (13) was prepared according to the following procedure: The aramid resin contained in coating liquid (13) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4241 g of NMP was charged into a flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in a manner calculated to give a moisture content of 410 ppm. The calcium chloride used was previously vacuum-dried at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.23 g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 115.48 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize Block A7, which consisted of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 1.00. 5. 61.53 g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 114.63 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing block B7 (poly(paraphenylene terephthalamide)) to extend on both sides of block A7. The molar ratio of PPD to TPC was 1.008. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (G) was obtained. In the block copolymer contained in aramid polymerization liquid (G), block A7 accounted for 50% of the entire molecule, and block B7 accounted for the remaining 50% of the entire molecule. 8. NMP as a diluent and calcium carbonate as a neutralizer were added to the aramid polymerization liquid (G) so that the solid content was 3% by weight. The "solid content" here refers to the content of aramid resin. This solution was stirred for 20 minutes to dilute and neutralize it. This neutralized liquid was degassed under reduced pressure to prepare a coating liquid (13).

[0165] [Production Example 9] Coating liquid (14) was prepared according to the following procedure: The aramid resin contained in coating liquid (14) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. Prepare a 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port. The scooter was allowed to dry thoroughly. 2. 4241 g of NMP was charged into the flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in a manner calculated so that the moisture content of the calcium chloride solution would be 360 ​​ppm. The calcium chloride used was previously vacuum-dried at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.62 g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 115.40 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize Block A8, which consisted of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 1.003. 5. 61.90 g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 114.00 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing block B8 (poly(paraphenylene terephthalamide)) to extend on both sides of block A8. The molar ratio of PPD to TPC was 1.019. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, aramid polymerization liquid (G) was obtained. In the block copolymer contained in aramid polymerization liquid (G), block A8 accounted for 50% of the entire molecule, and block B8 accounted for the remaining 50% of the entire molecule. 8. NMP as a diluent and calcium carbonate as a neutralizer were added to the aramid polymerization liquid (H) so that the solid content was 3% by weight. The "solid content" here refers to the content of aramid resin. This solution was stirred for 20 minutes to dilute and neutralize it. This neutralized liquid was degassed under reduced pressure to prepare a coating liquid (14).

[0166] [Production Example 10] Coating liquid (15) was prepared according to the following procedure: The aramid resin contained in coating liquid (15) contains a block copolymer having a poly(4,4'-diphenylsulfonyl terephthalamide) block. 1. A 5 L separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet, and a powder addition port was thoroughly dried. 2. 4241 g of NMP was charged into the flask. 326.1 g of calcium chloride was then added to the flask, and the temperature was raised to 100°C. This allowed the calcium chloride to completely dissolve, yielding a calcium chloride solution (7.14 wt%). Water was added to the calcium chloride solution in a manner calculated to give a moisture content of 150 ppm. The calcium chloride used was previously vacuum-dried at 200°C for 2 hours. 3. While maintaining the temperature of the polymerization system at 40°C, 141.04 g of DDS was added and completely dissolved. 4. The temperature of the polymerization system was cooled to 25°C. While maintaining the temperature of the polymerization system at 25±2°C, a total of 115.23 g of TPC was added in three portions. The reaction was allowed to proceed for 1 hour to synthesize Block A9, which consisted of poly(4,4'-diphenylsulfonylterephthalamide). The molar ratio of DDS to TPC was 1.001. 5. 61.50 g of PPD was added to the flask and allowed to dissolve completely for 1 hour. 6. While maintaining the temperature of the polymerization system at 25±2°C, a total of 113.86 g of TPC was added in three portions. The reaction was allowed to proceed for 1.5 hours, allowing block B9, consisting of poly(paraphenylene terephthalamide), to extend on both sides of block A9. The molar ratio of PPD to TPC at this time was 1.014. 7. The polymerization system was aged for 1 hour while maintaining the temperature at 20±2°C. In this way, an aramid polymerization liquid (I) was obtained. The block copolymer contained in the aramid polymerization liquid (I) was Block A9 accounts for 50% of the entire molecule, and block B9 accounts for the remaining 50% of the entire molecule. 8. NMP as a diluent and calcium carbonate as a neutralizer were added to the aramid polymerization liquid (I) so that the solid content was 3% by weight. The "solid content" here refers to the content of aramid resin. The solution was stirred for 20 minutes to dilute and neutralize it. The neutralized liquid was degassed under reduced pressure to prepare a coating liquid (15).

[0167] Example 1 Porous film (Porous polyethylene film, thickness: 9 μm, weight: 5 g / m 2 While conveying the porous film, the slurry coating liquid (1) prepared in Production Example 1 was coated on one side (surface) of the porous film. As a result, a coating film was formed on one side of the porous film. Then, while conveying the porous film on which the coating film was formed, the coating film and the porous film were passed through a precipitation tank set at 50°C and a relative humidity of 70%, and the coating film was exposed to air containing water vapor at 50°C and a relative humidity of 70%. This caused a block copolymer to precipitate on one side (surface) of the porous film, forming a coating layer. Next, a laminate consisting of the porous film and the coating layer precipitated on one side of the porous film was washed with water to remove calcium chloride and the solvent from the coating layer. The laminate was then dried to obtain a laminate separator (1) in which a porous layer was formed on one side of the porous film.

[0168] Example 2 A laminated separator (2) was obtained by carrying out the same operation as in Example 1, except that the slurry coating liquid (2) prepared in Production Example 2 was used instead of the slurry coating liquid (1).

[0169] Example 3 A laminated separator (3) was obtained by carrying out the same operation as in Example 1, except that the slurry coating liquid (3) prepared in Production Example 3 was used instead of the slurry coating liquid (1).

[0170] Example 4 A laminated separator (4) was obtained by carrying out the same operation as in Example 1, except that the slurry coating liquid (4) prepared in Production Example 4 was used instead of the slurry coating liquid (1).

[0171] Example 5 A laminated separator (5) was obtained by carrying out the same operation as in Example 1, except that the slurry coating liquid (5) prepared in Production Example 5 was used instead of the slurry coating liquid (1).

[0172] Example 6 The same operation as in Example 1 was carried out except that the slurry coating liquid (6) prepared in Production Example 6 was used instead of the slurry coating liquid (1), to obtain a laminated separator (6).

[0173] Example 7 The same operation as in Example 1 was carried out, except that the slurry coating liquid (7) prepared in Production Example 7 was used instead of the slurry coating liquid (1), to obtain a laminated separator (7).

[0174] Comparative Example 1 A laminated separator (8) was obtained by carrying out the same operation as in Example 1, except that the slurry coating liquid (8) prepared in Comparative Production Example 1 was used instead of the slurry coating liquid (1).

[0175] Comparative Example 2 Instead of the slurry coating liquid (1), the slurry coating liquid ( The same procedure as in Example 1 was carried out except that the laminated separator (9) was used, to obtain a laminated separator (9).

[0176] Comparative Example 3 The same operation as in Example 1 was carried out, except that the slurry coating liquid (10) prepared in Comparative Production Example 3 was used instead of the slurry coating liquid (1), to obtain a laminated separator (10).

[0177] Comparative Example 4 The same operation as in Example 1 was carried out, except that the slurry coating liquid (11) prepared in Comparative Production Example 4 was used instead of the slurry coating liquid (1), to obtain a laminated separator (11).

[0178] Comparative Example 5 A laminated separator (12) was obtained by the same operation as in Example 1, except that the slurry coating liquid (12) prepared in Comparative Production Example 5 was used instead of the slurry coating liquid (1).

[0179] Example 8 A laminated separator (13) was obtained in the same manner as in Example 1, except that the coating liquid (13) prepared in Production Example 8 was used instead of the slurry coating liquid (1).

[0180] Example 9 A laminated separator (14) was obtained by carrying out the same operation as in Example 1, except that the coating liquid (14) prepared in Production Example 9 was used instead of the slurry coating liquid (1).

[0181] Example 10 A laminated separator (15) was obtained in the same manner as in Example 1, except that the coating liquid (10) prepared in Production Example 10 was used instead of the slurry coating liquid (1).

[0182] 〔result〕 The compositions and measurement results of Examples 1 to 10 and Comparative Examples 1 to 5 are shown in the following Table 1. In Table 1, "- (0%)" means that the coating liquid used did not contain alumina.

[0183] [Table 1]

[0184] As shown in Table 1, the laminate separators (1) to (7) and (13) to (15) of Examples 1 to 10 were obtained using compositions in which the content of components eluted in NMP was more than 25.0 wt % and not more than 45.0 wt %. In contrast, the laminate separator (8) of Comparative Example 1 was obtained using a composition in which the content was more than 45.0 wt %. The laminate separators (9) to (12) of Examples 1 to 5 were obtained using compositions in which the content was 25.0 wt % or less. The laminate separators (1) to (7) and (13) to (15) of Examples 1 to 10 had a higher heat shape retention rate than the laminate separators (8), (9), (10), and (12) of Comparative Examples 1, 2, 3, and 5. Furthermore, the laminate separators (1) to (7) and (13) to (15) of Examples 1 to 10 had a lower increase in air permeability than the laminate separators (11) and (12) of Comparative Examples 4 and 5. [Industrial Applicability]

[0185] One aspect of the present invention can be used in the manufacture of a non-aqueous electrolyte secondary battery.

Claims

1. a resin comprising an amide bond, the resin having an amide bond contains a component that dissolves in N-methyl-2-pyrrolidone, a content of the component eluted in N-methyl-2-pyrrolidone being more than 25.0 wt % and not more than 45.0 wt % relative to the total weight of the resin having an amide bond,

2. The composition of claim 1 wherein the resin is an aramid resin.

3. The aramid resin is a block A mainly composed of a unit represented by the following formula (1); -(NH-Ar １ -NHCO-Ar ２ -CO)- formula (1) a block B mainly composed of a unit represented by the following formula (2); -(NH-Ar ３ -NHCO-Ar ４ -CO)- Formula (2) The composition of claim 2 comprising a block copolymer having the formula: (In formula (1) and formula (2), Ar １ , Ar ２ , Ar ３ and Ar ４ may be different for each unit, Ar １ , Ar ２ , Ar ３ and Ar ４ are each independently a divalent group having one or more aromatic rings, All Ar １ More than 50% of these have a structure in which two aromatic rings are linked by a sulfonyl bond, All Ar ３ 50% or less of the above have a structure in which two aromatic rings are connected by a sulfonyl bond, All Ar １ and Ar ３ Of these, 10 to 70% have a structure in which two aromatic rings are linked by a sulfonyl bond.

4. Further comprising a filler, 2. The composition according to claim 1, wherein the content of the filler is 20 to 90% by weight based on the total amount of the resin and the filler.

5. A layer for forming a laminate separator for a non-aqueous electrolyte secondary battery, comprising the composition according to claim 1 .

6. The layer for forming a laminate separator for a non-aqueous electrolyte secondary battery according to claim 5, which is a porous layer.

7. A laminate separator for a non-aqueous electrolyte secondary battery, comprising a polyolefin porous film and a layer for forming the laminate separator for a non-aqueous electrolyte secondary battery according to claim 5 laminated on one or both sides of the polyolefin porous film.

8. 8. The laminate separator for a non-aqueous electrolyte secondary battery according to claim 7, further comprising an adhesive layer in addition to the polyolefin porous film and the layer for forming the laminate separator for a non-aqueous electrolyte secondary battery.

9. A member for a non-aqueous electrolyte secondary battery, comprising a positive electrode, the laminate separator for a non-aqueous electrolyte secondary battery according to claim 7 or 8, and a negative electrode arranged in this order.

10. A non-aqueous electrolyte secondary battery comprising the laminate separator for a non-aqueous electrolyte secondary battery according to claim 7 or 8.