阅读说明：本技术 用于非水电解液二次电池用层叠间隔件的制造的组合物 (Composition for producing laminated separator for nonaqueous electrolyte secondary battery ) 是由 堀江健作 桥胁弘树 林英里 于 2021-06-29 设计创作，主要内容包括：本发明实现一种能够容易地发现非水电解液二次电池用层叠间隔件的缺陷的组合物。一种组合物,其包含溶剂和芳族聚酰胺树脂,上述芳族聚酰胺树脂中,(i)在主链中的芳香环内具有吸电子性基团,(ii)分子的至少一个末端为氨基,(iii)连接主链中所含的芳香环的键中,超过90％为酰胺键。(The invention provides a composition which can easily find defects in a laminated separator for a nonaqueous electrolyte secondary battery. A composition comprising a solvent and an aromatic polyamide resin, wherein (i) the aromatic ring in the main chain has an electron-withdrawing group, (ii) at least one end of the molecule has an amino group, and (iii) more than 90% of the bonds linking the aromatic rings in the main chain are amide bonds.)

1. A composition comprising a solvent and an aramid resin,

in the aromatic polyamide resin,

(i) an electron-withdrawing group is provided in the aromatic ring in the main chain,

(ii) at least one terminal end of the molecule is an amino group,

(iii) more than 90% of the bonds linking aromatic rings contained in the main chain are amide bonds.

2. The composition according to claim 1, wherein in the aramid resin,

(iv) at least 25% of units derived from an aromatic diamine have an electron-withdrawing group,

(v) 50% or less of the units derived from the acid chloride have an electron-withdrawing group.

3. The composition according to claim 1 or 2, wherein the electron-withdrawing group is 1 or more selected from the group consisting of a halogen group, a cyano group and a nitro group.

4. The composition of any of claims 1-3, wherein the aramid resin has an intrinsic viscosity of 0.5dL/g to 4.0 dL/g.

5. The composition of any one of claims 1-4, further comprising a filler.

6. The composition according to any one of claims 1 to 5, which is placed in a quartz cell having an optical path length of 5mm, and measured according to JIS K7361-1: 1997 total light transmittance of 5% or less.

7. A laminate comprising a polyolefin porous film and the composition according to any one of claims 1 to 6 laminated on one or both surfaces of the film.

8. A method for producing a laminated separator for a nonaqueous electrolyte secondary battery, comprising:

laminating the composition according to any one of claims 1 to 6 on one or both surfaces of a polyolefin porous film; and

and removing 99% or more of the solvent in the composition.

9. A laminated separator for a nonaqueous electrolyte secondary battery, which is obtained by laminating a porous polyolefin film and a porous layer containing a binder resin and a filler, wherein the weight ratio of the laminated separator to the porous polyolefin film is set in accordance with JIS K7361-1: 1997 the total light transmittance was 30% or less.

10. The laminated separator for nonaqueous electrolyte secondary batteries according to claim 9, wherein the binder resin is an aramid resin in which,

(i) an electron-withdrawing group is provided in the aromatic ring in the main chain,

(ii) at least one terminal end of the molecule is an amino group,

(iii) more than 90% of the bonds linking aromatic rings contained in the main chain are amide bonds.

Technical Field

The present invention relates to a composition that can be used for producing a laminated separator for a nonaqueous electrolyte secondary battery.

Background

A nonaqueous electrolyte secondary battery, particularly a lithium ion secondary battery, has been widely used as a battery for personal computers, mobile phones, portable information terminals, and the like because of its high energy density, and recently developed as a battery for vehicle mounting.

A laminated separator for a nonaqueous electrolyte secondary battery used as a member of a nonaqueous electrolyte secondary battery is generally produced by coating a coating liquid containing a binder resin, a filler, and the like on a polyolefin porous film as a substrate and forming a porous layer on one surface or both surfaces of the substrate.

As the binder resin, various resins such as (meth) acrylate resins, fluorine-containing resins, polyamide resins, and polyimide resins are known. For example, patent document 1 discloses a separator for a nonaqueous electrolyte secondary battery, which has a laminated structure of a predetermined wholly aromatic polyamide porous membrane and a porous membrane having a shutdown (shutdown) function.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2003-40999 (published 2003 2 month 13)

Disclosure of Invention

Problems to be solved by the invention

The conventional coating liquid is transparent or slightly colored to some extent, and therefore has the following problems: even when defects such as foreign matter, coating unevenness, air bubbles, dirt, pinholes, and the like are generated in the laminated separator for a nonaqueous electrolyte secondary battery after the coating liquid is applied to the substrate, it is difficult to find the defects. The same applies to the separator for a nonaqueous electrolyte secondary battery described in patent document 1.

On the other hand, the laminated separator for a nonaqueous electrolyte secondary battery is a member used in the nonaqueous electrolyte secondary battery. Therefore, the addition of some coloring component to the coating liquid is not preferable because it may adversely affect the performance of the nonaqueous electrolyte secondary battery, and may adversely affect the laminated separator for nonaqueous electrolyte secondary batteries.

Therefore, a technique is desired in which the coating liquid for forming the porous layer does not contain any coloring component and the above-described defects can be easily found.

Accordingly, an object of one embodiment of the present invention is to realize a composition that can easily detect a defect in a laminated separator for a nonaqueous electrolyte secondary battery.

Means for solving the problems

The present invention includes the inventions shown in [1] to [10] below.

[1] A composition comprising a solvent and an aramid resin,

among the above-mentioned aromatic polyamide resins, the aromatic polyamide resins,

(i) an electron-withdrawing group is provided in the aromatic ring in the main chain,

(ii) at least one terminal end of the molecule is an amino group,

(iii) more than 90% of the bonds linking aromatic rings contained in the main chain are amide bonds.

[2] The composition according to item [1], wherein, in the aromatic polyamide resin,

(iv) at least 25% of units derived from an aromatic diamine have an electron-withdrawing group,

(v) 50% or less of the units derived from the acid chloride have an electron-withdrawing group.

[3] The composition according to [1] or [2], wherein the electron-withdrawing group is at least 1 selected from the group consisting of a halogen group, a cyano group and a nitro group.

[4] The composition according to any one of [1] to [3], wherein the aromatic polyamide resin has an intrinsic viscosity of 0.5 to 4.0 dL/g.

[5] The composition according to any one of [1] to [4], further comprising a filler.

[6] The composition according to any one of [1] to [5], which is placed in a quartz cell having an optical path length of 5mm, according to JIS K7361-1: 1997 total light transmittance of 5% or less.

[7] A laminate comprising a polyolefin porous film and the composition according to any one of [1] to [6] laminated on one or both surfaces of the film.

[8] A method for producing a laminated separator for a nonaqueous electrolyte secondary battery, comprising:

laminating the composition according to any one of [1] to [6] on one surface or both surfaces of a polyolefin porous film; and

and removing 99% or more of the solvent in the composition.

[9] A laminated separator for a nonaqueous electrolyte secondary battery, which is obtained by laminating a porous polyolefin film and a porous layer containing a binder resin and a filler, wherein the weight ratio of the polyolefin film to the porous layer is determined in accordance with JIS K7361-1: 1997 the total light transmittance was 30% or less.

[10] The laminated separator for a nonaqueous electrolyte secondary battery according to item [9], wherein the binder resin is an aramid resin in which,

(i) an electron-withdrawing group is provided in the aromatic ring in the main chain,

(ii) at least one terminal end of the molecule is an amino group,

(iii) more than 90% of the bonds linking aromatic rings contained in the main chain are amide bonds.

ADVANTAGEOUS EFFECTS OF INVENTION

According to one embodiment of the present invention, defects in the laminated separator for a nonaqueous electrolyte secondary battery can be easily found.

Drawings

Fig. 1 is a graph showing total light transmittance of compositions prepared in examples and comparative examples.

Fig. 2 is a graph showing the total light transmittance of the laminated spacers for nonaqueous electrolyte secondary batteries prepared in examples and comparative examples.

Fig. 3 is a graph showing the color difference between a defective portion and a normal portion of the laminated spacer for nonaqueous electrolyte secondary batteries prepared in examples and comparative examples.

Detailed Description

An embodiment of the present invention will be described below, but the present invention is not limited to this. The present invention is not limited to the configurations described below, and various modifications can be made within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention. In the present specification, "a to B" indicating a numerical range means "a to B" unless otherwise specified.

(embodiment 1: composition ]

The composition of one embodiment of the present invention comprises a solvent and an aramid resin, among the above aramid resins,

(i) an electron-withdrawing group is provided in the aromatic ring in the main chain,

(ii) at least one terminal end of the molecule is an amino group,

(iii) more than 90% of the bonds linking aromatic rings contained in the main chain are amide bonds.

According to the above configuration, the aramid resin satisfies the above (i) to (iii), and thus a composition having a low total light transmittance can be obtained without adding a coloring component or the like separately as shown in examples described later.

As a result, the total light transmittance of the nonaqueous electrolyte secondary lamination separator including the porous layer obtained by laminating the composition on the polyolefin porous film can be reduced. Therefore, the presence or absence of defects in the nonaqueous electrolyte secondary lamination spacer can be easily detected.

The main chain of the aramid resin is, for example, a structure shown in parentheses in the following chemical formula. However, in the following chemical formula, the bond linking the aromatic rings contained in the main chain is only an amide bond, but is not necessarily limited thereto, and more than 90% of the bonds may be amide bonds. Examples of the other bond include an ether bond and a sulfonyl bond.

The proportion of the amide bond in the above bond is more preferably 95% or more, and most preferably 100%. The aromatic polyamide resin preferably does not have an ether bond as a bond linking aromatic rings contained in the main chain.

[ chemical formula 1]

Examples of the electron-withdrawing group include halogen, -CN and-NO₂、-⁺NH₃、 -CF₃、-CCl₃、-CHO、-COCH₃、-CO₂C₂H₅、-CO₂H、-SO₂CH₃、-SO₃H、 -OCH₃And the like. The electron-withdrawing group may be 1 or 2 or more.

Among them, from the viewpoint of price, the electron-withdrawing group is preferably 1 or more selected from the group consisting of a halogen group, a cyano group and a nitro group which are generally distributed.

Both ends or at least one end of the molecule of the aromatic polyamide resin is an amino group. That is, at least one of the aromatic rings at the end of the molecule has an amino group. By having an amino group at the terminal, the amino group and the aromatic ring portion function as chromophores, and the coloration of the polymer can be increased.

The aromatic polyamide resin satisfying the above (i) to (iii) can be produced by reacting an aromatic diamine with an aromatic carboxylic acid in a solvent.

The aromatic polyamide resin preferably has (iv) 25% or more of units derived from an aromatic diamine and (v) 50% or less of units derived from an acid chloride, the electron-withdrawing groups being present.

The "unit derived from an aromatic diamine" refers to a structural unit represented by- (NH-Ar-NH-). The structural unit also includes a structural unit having an amino group at the terminal, i.e., NH₂-Ar-NH-and-NH-Ar-NH₂. "25% or more of the units have an electron-withdrawing group" means that 25% or more of the aromatic rings (Ar) in the units present in the molecule of the aramid resin have an electron-withdrawing group.

The proportion of the unit derived from an aromatic diamine having an electron-withdrawing group is more preferably 50% or more, still more preferably 75% or more, and most preferably 100%.

The "unit derived from an acid chloride" means a structural unit represented by- (CO-Ar-CO) -. "50% or less of the units have an electron-withdrawing group" means that 50% or less of the aromatic rings (Ar) in the units present in the molecule of the aramid resin have an electron-withdrawing group. The lower the proportion of the electron-withdrawing group in the unit derived from the acid chloride, the more preferably 25% or less, the more preferably 10% or less, and the most preferably 0%.

By making the above-mentioned aramid resin satisfy the above-mentioned (iv) and (v), a composition having low total light transmittance can be more easily obtained.

The aromatic polyamide resin preferably has an intrinsic viscosity of 0.5 to 4.0dL/g, from the viewpoint of improving the heat resistance of the porous layer. The intrinsic viscosity can be confirmed by, for example, the method described in international publication 2016/002785. That is, 0.5g of the aramid resin was dissolved in 100mL of concentrated sulfuric acid and measured by using a capillary viscometer. The method of controlling the intrinsic viscosity can be controlled by adjusting the monomer feed.

The aromatic polyamide resin includes aromatic polyamide, wholly aromatic polyamide, and the like. The aromatic polyamide is preferably at least 1 resin selected from the group consisting of p- (p) -aromatic polyamide and m- (m) -aromatic polyamide.

Specific examples of the aramid resin include those selected from the group consisting of poly (p-phenylene terephthalamide), poly (m-phenylene isophthalamide), poly (m-phenylene terephthalamide), poly (p-benzamide), poly (m-benzamide), poly (4, 4 '-benzanilide terephthalamide), poly (4, 4' -biphenylene isophthalamide), poly (2, 6-biphenylene terephthalamide), poly (2, 6-biphenylene isophthalamide), poly (2-biphenylene terephthalamide), poly (p-phenylene terephthalamide/p-phenylene isophthalamide copolymer, poly (p-phenylene terephthalamide/2, 6-biphenylene terephthalamide copolymer), poly (m-phenylene terephthalamide/2-biphenylene terephthalamide copolymer, 6-dichloro-p-phenylenediamine copolymer, etc.

Among them, poly (p-phenylene terephthalamide), poly (m-phenylene terephthalamide), and p-phenylene terephthalamide/m-phenylene terephthalamide copolymers are preferable.

The solvent contained in the composition according to one embodiment of the present invention is preferably a solvent which does not adversely affect the base material, can uniformly and stably dissolve or disperse the aramid resin, and can uniformly and stably disperse the filler.

Examples of the solvent include nonpolar solvents described in international publication 2016/002785. Specific examples thereof include N-methylpyrrolidone, N-dimethylacetamide and N, N-dimethylformamide. These solvents may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

The composition of one embodiment of the present invention preferably further comprises a filler. The filler is preferably a heat-resistant filler. The heat-resistant filler may be an inorganic filler or an organic filler, and preferably contains an inorganic filler. The heat-resistant filler is a filler having a melting point of 150 ℃ or higher.

From the viewpoint of improving the heat resistance of the porous layer, the content of the filler in the composition is preferably 40% by weight or more and 70% by weight or less, assuming that the weight of the solid content of the composition is 100% by weight. The content is more preferably 50% by weight or more and less than 70% by weight.

As the filler, for example, 1 or more inorganic fillers selected from inorganic substances such as calcium carbonate, talc, clay, kaolin, silica, hydrotalcite, diatomaceous earth, magnesium carbonate, barium carbonate, calcium sulfate, magnesium sulfate, barium sulfate, aluminum hydroxide, boehmite, magnesium hydroxide, calcium oxide, magnesium oxide, titanium nitride, aluminum oxide (alumina), aluminum nitride, mica, zeolite, and glass can be used.

Among these, the filler is preferably a metal oxide filler from the viewpoint of improving the heat resistance of the porous layer. "Metal oxide filler" refers to an inorganic filler comprising a metal oxide. Examples of the metal oxide filler include inorganic fillers containing alumina and/or magnesia.

Examples of the organic material constituting the organic filler include homopolymers or copolymers of 2 or more kinds of monomers selected from styrene, vinyl ketone, acrylonitrile, methyl methacrylate, ethyl methacrylate, glycidyl acrylate, and methyl acrylate; fluorine-containing resins such as polytetrafluoroethylene, tetrafluoroethylene/hexafluoropropylene copolymer, tetrafluoroethylene/ethylene copolymer, and polyvinylidene fluoride; a melamine resin; urea resin; polyethylene; polypropylene; polyacrylic acid, polymethacrylic acid; resorcinol resins, etc.

The average particle diameter (D50) of the filler is preferably 0.001 to 10 μm, more preferably 0.01 to 8 μm, and still more preferably 0.05 to 5 μm. The average particle diameter of the filler was measured using MICROTRAC (MODEL: MT-3300EXII) manufactured by Nikkiso K.K.

The shape of the filler varies depending on the method for producing an organic or inorganic material as a raw material, the dispersion condition of the filler when preparing a coating liquid for forming the porous layer, and the like, and thus may be any shape such as a spherical shape, an elliptical shape, a short shape, a gourd shape, or an irregular shape having no specific shape.

The composition of one embodiment of the present invention was placed in a quartz cell having an optical path length of 5mm, and the optical path length was measured in accordance with JIS K7361-1: the total light transmittance measured in 1997 is preferably 5% or less.

According to this configuration, since the total light transmittance is sufficiently low, the total light transmittance of the porous layer formed using the composition is sufficiently low. Therefore, a laminated separator for a nonaqueous electrolyte secondary battery, in which defects can be easily detected, can be provided.

The total light transmittance is more preferably 3% or less, still more preferably 1.5% or less, and particularly preferably 0.5% or less.

The measurement apparatus is a device that is measured in accordance with JIS K7361-1: the measurement device described in 1997 may be one including a stabilized light source, an optical system and a photometer combined with the light source, and an integrating sphere having an opening and preventing light from entering from outside. As the light source, a C light source was used. For example, COH-7700 manufactured by Nippon electric appliances corporation and the like can be used.

JIS K7361-1: 1997 specifies a test method for total light transmission in the visible region of flat, transparent, essentially colorless plastic, so that the test piece is placed directly on the integrating sphere. On the other hand, the composition of one embodiment of the present invention is a composition comprising a solvent and an aramid resin, and thus placed in a quartz cell having an optical path length of 5mm to measure the total light transmittance. In addition to this, the ink composition is prepared according to JIS K7361-1: total light transmittance was measured by the method specified in 1997. The obtained value is the above-mentioned total light transmittance.

The composition according to one embodiment of the present invention can be obtained by mixing the solvent, the aramid resin, and the filler as needed. When the filler is used, the content of the filler is preferably 40 to 70% by weight, and more preferably 50 to 70% by weight, from the viewpoint of improving the heat resistance of the porous layer, assuming that the weight of the aramid resin and the filler is 100% by weight.

Other embodiments of the present invention will be described below. For convenience of explanation, the matters described in the above embodiments will not be described repeatedly.

(embodiment 2: laminate ]

The laminate of one embodiment of the present invention is a laminate in which the composition of one embodiment of the present invention is laminated on one side or both sides of a polyolefin porous film. The composition is removed from the solvent contained in the composition to form a porous layer, whereby a laminated separator for a nonaqueous electrolyte secondary battery can be obtained. That is, the laminate corresponds to a semi-finished product of a laminate spacer for a nonaqueous electrolyte secondary battery.

As described in embodiment 1, since the total light transmittance of the composition is low, the laminate can provide a laminate spacer for a nonaqueous electrolyte secondary battery, in which defects can be easily detected.

The polyolefin porous film (hereinafter, also simply referred to as "porous film") contains polyolefin as a main component, has a plurality of connected pores therein, and can pass gas and liquid from one surface to the other surface. The porous film serves as a base material of the laminate on which the porous layer is formed. The porous layer has a structure in which a plurality of pores are formed in the porous layer and the pores are connected to each other, and gas or liquid can pass through from one surface to the other surface.

The proportion of the polyolefin in the porous membrane is 50% by volume or more, more preferably 90% by volume or more, and still more preferably 95% by volume or more of the entire porous membrane.

Further, the polyolefin more preferably contains a compound having a weight average molecular weight of 5X 10⁵～15×10⁶The high molecular weight component of (1). In particular, it is more preferable that the polyolefin contains a high molecular weight component having a weight average molecular weight of 100 ten thousand or more because the strength of the laminate is improved.

Examples of the polyolefin include homopolymers and copolymers obtained by polymerizing monomers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, and 1-hexene. Examples of the homopolymer include polyethylene, polypropylene, and polybutylene. Examples of the copolymer include an ethylene/propylene copolymer.

Among these, polyethylene is more preferable because it can prevent an excessive current from flowing at a lower temperature. Examples of the polyethylene include low-density polyethylene, high-density polyethylene, linear polyethylene (ethylene/α -olefin copolymer), and ultrahigh-molecular-weight polyethylene having a weight-average molecular weight of 100 ten thousand or more. Among them, ultrahigh molecular weight polyethylene having a weight average molecular weight of 100 ten thousand or more is more preferable.

The porous film preferably has a film thickness of 4 to 40 μm, more preferably 5 to 30 μm, and further preferably 6 to 15 μm.

The weight per unit area of the porous membrane can be appropriately determined in consideration of the strength, the membrane thickness, the weight, and the handling property. However, in order to increase the weight energy density and the volume energy density of the nonaqueous electrolyte secondary battery, the weight per unit area is preferably 4 to 15g/m²More preferably 4 to 12g/m²More preferably 5 to 10g/m²。

The air permeability of the porous film is preferably 30 to 500sec/100mL, more preferably 50 to 300sec/100mL in terms of Gurley value. By providing the porous membrane with the air permeability, sufficient ion permeability can be obtained.

The air permeability of the laminated separator for a nonaqueous electrolyte secondary battery, which is obtained by laminating the composition according to one embodiment of the present invention on a porous film to form a porous layer, is preferably 30 to 1000sec/100mL, more preferably 50 to 800sec/100mL in terms of Gurley. The laminated separator for a nonaqueous electrolyte secondary battery can obtain sufficient ion permeability in a nonaqueous electrolyte secondary battery by having the above air permeability.

In order to increase the amount of electrolyte to be held and to reliably prevent excessive current flow at a lower temperature, the porosity of the porous film is preferably 20 to 80 vol%, more preferably 30 to 75 vol%. In order to obtain sufficient ion permeability and prevent particles from entering the positive electrode and the negative electrode, the pore diameter of the pores of the porous film is preferably 0.30 μm or less, more preferably 0.14 μm or less, and still more preferably 0.10 μm or less.

The method for producing the polyolefin porous membrane is not particularly limited. Examples of the method include the following steps.

(A) A step of kneading ultra-high molecular weight polyethylene, low molecular weight polyethylene having a weight average molecular weight of 1 ten thousand or less, a pore-forming agent such as calcium carbonate or a plasticizer, and an antioxidant to obtain a polyolefin resin composition,

(B) a step of rolling the obtained polyolefin resin composition with a pair of rolling rolls, stretching the composition with a winding roll having a changed speed ratio, and cooling the composition in stages to form a sheet,

(C) a step of removing the pore-forming agent from the obtained sheet with an appropriate solvent,

(D) and a step of stretching the sheet from which the pore-forming agent has been removed at an appropriate stretching ratio.

The composition can be laminated on one side or both sides of the polyolefin porous film by, for example, a gravure coating method, a dip coating method, a bar coating method, or a die coating method.

(embodiment 3: method for producing laminated separator for nonaqueous electrolyte secondary battery

The method for producing a laminated separator for a nonaqueous electrolyte secondary battery according to one embodiment of the present invention includes a step of laminating the composition according to one embodiment of the present invention on one or both surfaces of a polyolefin porous film; and removing 99% or more of the solvent in the composition.

The step of laminating the above-described composition on the polyolefin porous membrane can be performed by a gravure coating method or the like as described in embodiment 2. As the step of removing 99% or more of the solvent in the composition, a method of drying and removing the solvent is exemplified. Removal of more than 99% of the solvent can be confirmed by thermogravimetric analysis (TGA).

Through the above steps, the composition forms a porous layer on one or both surfaces of the porous film (substrate). Thus, a laminated separator for a nonaqueous electrolyte secondary battery was obtained.

The solvent may be removed by the following method, for example.

(1) After the composition is applied to one surface or both surfaces of a substrate, the substrate is immersed in a precipitation solvent which is a poor solvent for the aramid resin, thereby precipitating the aramid resin to form a porous layer, and then the porous layer is dried to remove the solvent.

(2) After the composition is applied to one or both surfaces of a substrate, an aramid resin is precipitated using a low boiling point solvent to form a porous layer, and then the porous layer is dried to remove the solvent.

Examples of the precipitation solvent include water, ethanol, isopropanol, and acetone.

(embodiment 4: laminated spacer for nonaqueous electrolyte secondary battery

A laminated separator for a nonaqueous electrolyte secondary battery according to one embodiment of the present invention is a laminated separator for a nonaqueous electrolyte secondary battery in which a polyolefin porous film and a porous layer containing a binder resin and a filler are laminated, and has a total light transmittance of 30% or less as measured according to JIS K7361-1: 1997.

In the laminated separator for a nonaqueous electrolyte secondary battery according to one embodiment of the present invention, the binder resin is an aramid resin, and among the aramid resins,

(i) an electron-withdrawing group is provided in the aromatic ring in the main chain,

(ii) at least one terminal end of the molecule is an amino group,

(iii) more than 90% of the bonds linking aromatic rings contained in the main chain are amide bonds.

(embodiment 5: member for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery

A member for a nonaqueous electrolyte secondary battery according to an embodiment of the present invention is formed by arranging a positive electrode, the above-described laminated separator for a nonaqueous electrolyte secondary battery, and a negative electrode in this order. A nonaqueous electrolyte secondary battery according to an embodiment of the present invention includes the above-described laminated separator for a nonaqueous electrolyte secondary battery. The nonaqueous electrolyte secondary battery generally has a structure in which a negative electrode and a positive electrode face each other with the above-described laminated separator for nonaqueous electrolyte secondary batteries interposed therebetween. In the nonaqueous electrolyte secondary battery, the battery element in which the structure is impregnated with the electrolyte is sealed in the exterior material. For example, the nonaqueous electrolyte secondary battery is a lithium ion secondary battery that obtains electromotive force by doping and dedoping of lithium ions.

< Positive electrode >

As the positive electrode, for example, a positive electrode sheet having a structure in which an active material layer containing a positive electrode active material and a binder is formed on a current collector can be used. The active material layer may further contain a conductive agent.

Examples of the positive electrode active material include materials capable of doping and dedoping lithium ions.

Examples of the material include materials containing at least 1 type of V, Ti, Cr, Mn, Fe, C_oAnd lithium composite oxides of transition metals such as Ni and Cu. As the lithium composite oxide, there is a lithium composite oxide,examples thereof include a lithium composite oxide having a layered structure, a lithium composite oxide having a spinel structure, and a solid solution lithium-containing transition metal oxide containing a lithium composite oxide having both a layered structure and a spinel structure. Further, lithium cobalt composite oxide and lithium nickel composite oxide are also included. Further, there may be mentioned those obtained by substituting a part of transition metal atoms which are the main components of these lithium composite oxides 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.

Examples of the lithium composite oxide obtained by substituting a part of the transition metal atoms which are the main component of the lithium composite oxide with another element include a lithium cobalt composite oxide having a layered structure represented by the following formula (2), a lithium nickel composite oxide represented by the following formula (3), a lithium manganese composite oxide having a spinel structure represented by the following formula (4), a solid solution lithium-containing transition metal oxide represented by the following formula (5), and the like.

Li[Li_x(Co_1-aM¹ _a)_1-x]O₂···(2)

(in the formula (2), M¹Is at least 1 metal selected from 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 ≤ O.30 and 0 ≤ a ≤ 0.5. )

Li[Li_y(Ni_1-bM² _b)_1-y]O₂···(3)

(in the formula (3), M²Is at least 1 metal selected from Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn and W, and satisfies-0.1-0.30 y and 0-0.5B. )

Li_zMn_2-cM³ _cO₄···(4)

(in the formula (4), M³Is at least 1 metal selected from Na, K, B, F, Al, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn and W, and satisfies 0.9. ltoreq. z, 0. ltoreq. c.ltoreq.1.5. )

Li_1+wM⁴ _dM⁵ _eO₂···(5)

(in the formula (5), M⁴And M⁵Is at least 1 metal selected from Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mg and Ca, and satisfies 0 < w < 1/3, 0 < d < 2/3, 0 < e < 2/3, and w + d + e ═ 1. )

Specific examples of the lithium composite oxide represented by the above formulas (2) to (5) include LiCoO₂、LiNiO₂、LiMnO₂、LiNi_0.8Co_0.2O₂、LiNi_0.5Mn_0.5O₂、 LiNi_0.85Co_0.10Al_0.05O₂、LiNi_0.8Co_0.15Al_0.05O₂、LiNi_0.5Co_0.2Mn_0.3O₂、 LiNi_0.6Co_0.2Mn_0.2O₂、LiNi_0.33Co_0.33Mn_0.33O₂、LiMn₂O₄、LiMn_1.5Ni_0.5O₄、 LiMn_1.5Fe_0.5O₄、LiCoMnO₄、Li_1.21Ni_0.20Mn_0.59O₂、Li_1.22Ni_0.20Mn_0.58O₂、 Li_1.22Ni_0.15Co_0.10Mn_0.53O₂、Li_1.07Ni_0.35Co_0.08Mn_0.50O₂、 Li_1.07Ni_0.36Co_0.08Mn_0.49O₂And the like.

In addition, lithium composite oxides other than the lithium composite oxides represented by the above formulas (2) to (5) can be preferably used as the positive electrode active material. Examples of such a lithium composite oxide include LiNiVO₄、LiV₃O₆、Li_1.2Fe_0.4Mn_0.4O₂And the like.

Examples of a material that can be preferably used as the positive electrode active material other than the lithium composite oxide include, for example, a phosphate having an olivine-type structure, and a phosphate having an olivine-type structure represented by the following formula (6).

Li_v(M⁶ _fM⁷ _gM⁸ _hM⁹ _i)_jPO₄···(6)

(in the formula (6), M⁶Is Mn, Co or Ni, M⁷Is Ti, V, Cr, Mn, Fe, Co, Ni, Zr, Nb or Mo, M⁸M is any one of transition metals excluding elements of groups VIA and VIIA of the periodic Table of elements, or any one of main group elements⁹In order to exclude any of transition metals of elements of groups VIA and VIIA of the periodic Table of elements in Japan, or any of elements of the main group, 1.2. gtoreq.a.gtoreq.0.9, 1. gtoreq.b.gtoreq.0.6, 0.4. gtoreq.c.0, 0.2. gtoreq.d.gtoreq.0, 0.2. gtoreq.e.gtoreq.0, and 1.2. gtoreq.f.gtoreq.0.9 are satisfied. ).

The positive electrode active material preferably has a coating layer on the surface of the particles of the lithium metal composite oxide constituting the positive electrode active material. Examples of the material constituting the coating layer include a metal composite oxide, a metal salt, a boron-containing compound, a nitrogen-containing compound, a silicon-containing compound, a sulfur-containing compound, and the like, and among them, a metal composite oxide is preferably used.

As the metal composite oxide, an oxide having lithium ion conductivity is preferably used. Examples of such a metal composite oxide include a metal composite oxide of Li and at least 1 element selected from Nb, Ge, Si, P, Al, W, Ta, Ti, S, Zr, Zn, V, and B. If the positive electrode active material has a coating layer, the coating layer can suppress side reactions at the interface between the positive electrode active material and the electrolyte at high voltage, and the obtained secondary battery can have a longer life. In addition, formation of a high-resistance layer at the interface between the positive electrode active material and the electrolyte can be suppressed, and high output of the obtained secondary battery can be achieved.

< nonaqueous electrolyte solution >

As the nonaqueous electrolytic solution, for example, a nonaqueous electrolytic solution in which a lithium salt is dissolved in an organic solvent can be used. As the lithium salt, LiClO is mentioned₄、LiPF₆、LiAsF₆、LiSbF₆、 LiBF₄、LiSO₃F、LiCF₃SO₃、LiN(SO₂CF₃)₂、LiN(SO₂C₂F₅)₂、 LiN(SO₂CF₃)(COCF₃)、Li(C₄F₉SO₃)、LiC(SO₂CF₃)₃、Li₂B₁₀Cl₁₀LiBOB (here, BOB is bis (oxalato) borate), lithium salt of lower aliphatic carboxylic acid, LiAlCl₄And the like. These may be used alone or in the form of a mixture of 2 or more. Among them, as the lithium salt, it is preferable to use a lithium salt containing LiPF selected from fluorine₆、LiAsF₆、LiSbF₆、LiBF₄、LiSO₃F、LiCF₃SO₃、LiN (SO₂CF₃)₂And LiC (SO)₂CF₃)₃At least 1 kind of lithium salt.

As the organic solvent, for example, carbonates such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 4-trifluoromethyl-1, 3-dioxolan-2-one, and 1, 2-bis (methoxycarbonyloxy) ethane; ethers such as 1, 2-dimethoxyethane, 1, 3-dimethoxypropane, methyl pentafluoropropyl ether, 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-oxazolidinone; sulfur-containing compounds such as sulfolane, dimethyl sulfoxide and 1, 3-propanesultone, or solvents obtained by further introducing fluorine groups into these organic solvents (solvents obtained by substituting 1 or more of the hydrogen atoms of the organic solvent with fluorine atoms).

As the organic solvent, 2 or more of them are preferably used in combination. Among them, a mixed solvent containing a carbonate is preferable, and a mixed solvent of a cyclic carbonate and a non-cyclic carbonate and a mixed solvent of a cyclic carbonate and an ether are more preferable. As the mixed solvent of the cyclic carbonate and the acyclic carbonate, a mixed solvent containing ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate is preferable. The nonaqueous electrolytic solution using such a mixed solvent has the following advantages: the working temperature range is wide, and the material is not easy to deteriorate even when used under high voltage, is not easy to deteriorate even when used for a long time, and is difficult to decompose even when a graphite material such as natural graphite or artificial graphite is used as an active material of a negative electrode.

In addition, as the nonaqueous electrolytic solution, in order to improve the safety of the obtained nonaqueous electrolyte secondary battery, it is preferable to use a nonaqueous electrolytic solution containing LiPF₆And the like, a fluorine-containing lithium salt and an organic solvent having a fluorine substituent. A mixed solvent containing dimethyl carbonate and ethers having a fluorine substituent such as methyl pentafluoropropyl ether and 2, 2, 3, 3-tetrafluoropropyl difluoromethyl ether is more preferable because the capacity retention rate is high even when discharge is performed at a high voltage.

< negative electrode >

As the negative electrode, 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 can be used. The active material layer may further contain a conductive agent.

< negative electrode active Material >

Examples of the negative electrode active material include materials capable of doping and dedoping lithium ions at a lower potential than that of the positive electrode, for example, carbon materials, chalcogenides (oxides, sulfides, and the like), nitrides, metals, and alloys.

Examples of carbon materials that can be used as the negative electrode active material include graphite such as natural graphite and artificial graphite, coke, carbon black, pyrolytic carbon, carbon fiber, and a fired product of an organic polymer compound.

Examples of the oxide that can be used as the negative electrode active material include SiO₂SiO, etc. are represented by the formula SiO_x(here, x is a positive real number); TiO 2₂TiO, etc. are represented by the formula_xAn oxide of titanium (where x is a positive real number); v₂O₅、 VO₂Equal formula V_xO_y(here, x)And y is a positive real number); fe₃O₄、Fe₂O₃FeO, etc. by the formula Fe_xO_y(here, x and y are positive real numbers) iron oxides; SnO₂SnO, etc. by the formula_x(here, x is a positive real number); WO₃、WO₂Etc. represented by the general formula WO_x(here, x is a positive real number); li₄Ti₅O₁₂、LiVO₂And the like contain lithium and titanium or vanadium; and the like.

Examples of the sulfide that can be used as the negative electrode active material include Ti₂S₃、TiS₂TiS, etc. are represented by the formula Ti_xS_y(here, x and y are positive real numbers) a sulfide of titanium; v₃S₄、VS₂Sulfides of vanadium represented by the formula VSx (here, x is a positive real number); fe₃S₄、FeS₂FeS, etc. of the formula Fe_xS_y(here, x and y are positive real numbers) iron sulfides; mo₂S₃、MoS₂Iso-formula Mo_xS_y(here, x and y are positive real numbers) represents a molybdenum sulfide; SnS₂SnS, etc. formula_x(here, x is a positive real number); WS₂Is of the formula WS_x(here, x is a positive real number) a sulfide of tungsten; sb₂S₃Has the formula Sb_xS_y(here, x and y are positive real numbers) represents sulfides of antimony; se₅S₃、SeS₂SeS, et al, by formula Se_xS_y(here, x and y are positive real numbers) represents a sulfide of selenium.

Examples of the nitride that can be used as the negative electrode active material include Li₃N、 Li_3-xA_xAnd lithium-containing nitrides such as N (wherein A is either or both of Ni and Co, and 0 < x < 3.).

These carbon materials, oxides, sulfides, and nitrides may be used alone in 1 kind, or may be used in combination in 2 or more kinds. These carbon materials, oxides, sulfides, and nitrides may be either crystalline or amorphous. These carbon materials, oxides, sulfides, and nitrides are mainly supported on the negative electrode current collector and used as an electrode.

Examples of the metal that can be used as the negative electrode active material include lithium metal, silicon metal, and tin metal.

Further, a composite material containing Si or Sn as the 1 st constituent element, and in addition thereto, the 2 nd constituent element and the 3 rd constituent element is exemplified. The 2 nd constituent element is, for example, at least 1 of cobalt, iron, magnesium, titanium, vanadium, chromium, manganese, nickel, copper, zinc, gallium, and zirconium. The 3 rd constituent element is, for example, at least 1 of boron, carbon, aluminum, and phosphorus.

In particular, from the viewpoint of obtaining a high battery capacity and excellent battery characteristics, the metal material is preferably a silicon or tin monomer (which may contain a trace amount of impurities), or SiO_v (0＜v≤2)、SnO_w(w is more than or equal to 0 and less than or equal to 2), Si-Co-C composite materials, Si-Ni-C composite materials, Sn-Co-C composite materials and Sn-Ni-C composite materials.

The nonaqueous electrolyte secondary battery according to one embodiment of the present invention includes the laminated separator for nonaqueous electrolyte secondary batteries according to one embodiment of the present invention or the member for nonaqueous electrolyte secondary batteries according to one embodiment of the present invention.

[ examples ] A method for producing a compound

The present invention will be described in further detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

< test method >

(1. measurement of Total light transmittance)

The compositions prepared in examples and comparative examples were placed in a quartz cell having an optical path length of 5mm, and the optical path length was measured by using a COH7700 manufactured by Nippon Denshoku industries Co., Ltd in accordance with JIS K7361-1: 1997 total light transmittance was measured.

Further, using COH7700 as described above, the composition was measured according to JIS K7361-1: 1997 the total light transmittance of the laminated separators for nonaqueous electrolyte secondary batteries prepared in examples and comparative examples was measured. In this case, the measurement was performed using a C light source, with the coated surface being disposed in contact with the integrating sphere, without using the quartz cell.

(2. measurement of color difference between defective portion and normal portion)

The laminated spacers for nonaqueous electrolyte secondary batteries prepared in examples and comparative examples were placed on a white backlight. Next, the pseudo defect and the normal portion around the pseudo defect were photographed using a digital camera (SONY CyberShot (registered trademark) DSC-WX350) from above 30cm of the above laminated spacer for a nonaqueous electrolyte secondary battery under the condition of F3.5, ISO 80, and 1/250. The above-mentioned suspected defect is a portion into which air bubbles were taken when the compositions prepared in examples and comparative examples were applied to a substrate in order to prepare the above-mentioned laminated separator for a nonaqueous electrolyte secondary battery.

With respect to the captured image, RGB values at the suspected defect 1 and the normal portion 1 were read using a color sampling tool (japanese: スポイトッール) for drawing Microsoft (registered trademark), and the color difference between the suspected defect and the normal portion was calculated based on the following equation. The total of three combinations of the pseudo defects and the normal portions of the read RGB values are calculated, and the average values of the color differences obtained are obtained.

[ mathematical formula 1]

In the formula, R₁、G₁、B₁The R value, G value and B value of the normal part are respectively. In addition, R₂、G₂、B₂The values are the R value, G value and B value of the suspected defect.

[ example 1]

(1. preparation of composition)

A500 mL separable flask equipped with a stirring blade, a thermometer, a nitrogen inlet tube, and a powder addition port was prepared. The flask was sufficiently dried by flowing nitrogen into the interior thereof. Then, 409.2g of N-methyl-2-pyrrolidone (hereinafter, abbreviated as NMP) as an organic solvent was added to the flask, 30.8g of calcium chloride (used after vacuum drying at 200 ℃ for 2 hours) as a chloride was added, and the temperature was raised to 100 ℃ to completely dissolve the calcium chloride. Then, the temperature of the obtained solution was returned to room temperature (25 ℃ C.), and the water content of the solution was adjusted to 500 ppm.

Next, 7.44g of 2-chloro-p-phenylenediamine, which is an aromatic diamine, was added and completely dissolved. While the temperature of the solution was kept at 20. + -. 2 ℃ and stirred, 10.29g of terephthaloyl dichloride (hereinafter abbreviated as TPC) as an aromatic dicarboxylic acid was added thereto.

By the above method, an aramid resin 1 having a chlorine group as an electron-withdrawing group in the aromatic ring in the main chain, amino groups at both ends of the molecule, 100% of the bonds linking the aromatic rings contained in the main chain being an amide bond, 100% of the units derived from an aromatic diamine having an electron-withdrawing group, and units derived from an acid chloride having no electron-withdrawing group and having an intrinsic viscosity of 1.5dL/g was obtained. Both ends of the molecule of the aramid resin 1 are aniline having a chlorine group.

Next, aramid resin 1, large-particle-size alumina and small-particle-size alumina as fillers, and N-methyl-6-pyrrolidone (NMP) as a solvent were mixed to prepare composition 1 in which the total concentration of aramid resin 1 and fillers was 6 wt%. At this time, in order to set the content of the filler in the porous layer described later to 66 wt%, assuming that the weight of the aramid resin 1 and the filler is 100 wt%, the aramid resin 1, the filler, and the solvent are mixed so that the content of the filler becomes 66 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery)

Composition 1 was coated on one side of a porous film obtained by drawing a polyolefin resin composition containing ultrahigh molecular weight polyethylene at a coating speed of 1.2m/min by fixing the gap of a baker (japanese: べ force one) type applicator to 2mil using a model G-7 bar coater made of tecno SUPPLY co. Next, the aramid resin 1 was precipitated in an environment of 50 ℃ and 70% humidity, and then washed with water and dried to obtain a laminated separator 1 for a nonaqueous electrolyte secondary battery in which a porous layer was laminated on the surface of a base material. At this time, it was confirmed by thermogravimetric analysis (TGA) that 99% or more of the solvent in the composition was removed.

(3. measurement of Total light transmittance and measurement of color Difference)

The total light transmittance of composition 1 was measured based on the above < test method >, and the color difference was measured using the laminated separator 1 for a nonaqueous electrolyte secondary battery. The results are shown in table 1, table 2, and fig. 1 to 3.

[ example 2]

(1. preparation of composition)

An aramid resin was produced in the same manner as in example 1, except that 5.60g of 2-chloro-1, 4-phenylenediamine, 1.42g of p-phenylenediamine, and 10.54g of TPC, which is an aromatic dicarboxylic acid, were used as the aromatic diamine. An aramid resin 2 having a chlorine group as an electron-withdrawing group in the aromatic ring in the main chain, amino groups at both ends of the molecule, 100% of the bonds linking the aromatic rings contained in the main chain being an amide bond, 75% of the units derived from an aromatic diamine having an electron-withdrawing group, and units derived from an acid chloride having no electron-withdrawing group and having an intrinsic viscosity of 1.6dL/g was obtained.

Next, aramid resin 2, large-particle-size alumina and small-particle-size alumina as fillers, and NMP as a solvent were mixed to prepare composition 2 in which the total concentration of aramid resin 2 and fillers was 4 wt%. At this time, in order to set the content of the filler in the porous layer described later to 66 wt%, assuming that the weight of the aramid resin 2 and the filler is 100 wt%, the aramid resin 2, the filler, and the solvent are mixed so that the content of the filler becomes 66 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery, measurement of Total light transmittance and measurement of color Difference)

A laminated separator 2 for a nonaqueous electrolyte secondary battery was obtained in the same manner as in example 1, except that the composition 2 was used instead of the composition 1. The total light transmittance of composition 2 was measured based on the above < test method >, and the color difference was measured using the laminated separator 2 for a nonaqueous electrolyte secondary battery. The results are shown in table 1, table 2, and fig. 1 to 3.

[ example 3]

(1. preparation of composition)

The production was carried out in the same manner as in example 1 except that 3.73g of 2-chloro-1, 4-phenylenediamine, 2.83g of p-phenylenediamine and 10.54g of TPC, which is an aromatic dicarboxylic acid, were used as the aromatic diamine. An aramid resin 3 having a chlorine group as an electron-withdrawing group in the aromatic ring in the main chain, amino groups at both ends of the molecule, 100% of the bonds linking the aromatic rings contained in the main chain being an amide bond, 50% of the units derived from an aromatic diamine having an electron-withdrawing group, and units derived from an acid chloride having no electron-withdrawing group and having an intrinsic viscosity of 1.1dL/g was obtained.

Next, aramid resin 3, large-particle-size alumina and small-particle-size alumina as fillers, and NMP as a solvent were mixed to prepare composition 3 in which the total concentration of aramid resin 3 and fillers was 4 wt%. At this time, in order to set the content of the filler in the porous layer described later to 66 wt%, assuming that the weight of the aramid resin 3 and the filler is 100 wt%, the aramid resin 3, the filler, and the solvent are mixed so that the content of the filler becomes 66 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery, measurement of Total light transmittance and measurement of color Difference)

A laminated separator 3 for a nonaqueous electrolyte secondary battery was obtained in the same manner as in example 1, except that the composition 3 was used instead of the composition 1. The total light transmittance of composition 3 was measured based on the above < test method >, and the color difference of the laminated separator 3 for a nonaqueous electrolyte secondary battery was measured. The results are shown in table 1, table 2, and fig. 1 to 3.

[ example 4]

(1. preparation of composition)

An aramid resin was produced in the same manner as in example 1 except that 1.87g of 2-chloro-1, 4-phenylenediamine, 4.25g of p-phenylenediamine, and 10.54g of TPC, which is an aromatic dicarboxylic acid, were used as the aromatic diamine. An aramid resin 4 having a chlorine group as an electron-withdrawing group in the aromatic ring in the main chain, amino groups at both ends of the molecule, 100% of the bonds linking the aromatic rings contained in the main chain being an amide bond, 25% of the units derived from an aromatic diamine having an electron-withdrawing group, and units derived from an acid chloride having no electron-withdrawing group and having an intrinsic viscosity of 0.8dL/g was obtained.

Next, aramid resin 4, large-particle-size alumina and small-particle-size alumina as fillers, and NMP as a solvent were mixed to prepare composition 4 in which the total concentration of aramid resin 4 and fillers was 4 wt%. At this time, in order to set the content of the filler in the porous layer described later to 66 wt%, assuming that the weight of the aramid resin 4 and the filler is 100 wt%, the aramid resin 4, the filler, and the solvent are mixed so that the content of the filler becomes 66 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery, measurement of Total light transmittance and measurement of color Difference)

A laminated separator 4 for a nonaqueous electrolyte secondary battery was obtained in the same manner as in example 1, except that the composition 4 was used instead of the composition 1. The total light transmittance of the composition 4 was measured based on the above < test method >, and the color difference of the laminated separator 4 for a nonaqueous electrolyte secondary battery was measured. The results are shown in table 1, table 2, and fig. 1 to 3.

[ example 5]

(1. preparation of composition)

An aramid resin was produced in the same manner as in example 1, except that 5.40g of 2-cyano-1, 4-phenylenediamine, which is an aromatic diamine, and 8.16g of TPC, which is an aromatic dicarboxylic acid, were used. An aramid resin 5 having a cyano group as an electron-withdrawing group in the aromatic ring in the main chain, amino groups at both ends of the molecule, 100% of the bonds linking the aromatic rings contained in the main chain being an amide bond, 100% of the units derived from an aromatic diamine having an electron-withdrawing group, and units derived from an acid chloride having no electron-withdrawing group and having an intrinsic viscosity of 2.6dL/g was obtained. The aromatic polyamide resin 5 has aniline having cyano groups at both ends of the molecule.

Next, aramid resin 5, large-particle-size alumina and small-particle-size alumina as fillers, and NMP as a solvent were mixed to prepare composition 5 having a total concentration of aramid resin 5 and fillers of 4 wt%. At this time, in order to set the content of the filler in the porous layer described later to 66 wt%, the aramid resin 5, the filler, and the solvent are mixed so that the content of the filler becomes 66 wt% when the weight of the aramid resin 5 and the filler is set to 100 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery, measurement of Total light transmittance and measurement of color Difference)

A laminated separator 5 for a nonaqueous electrolyte secondary battery was obtained in the same manner as in example 1, except that the composition 5 was used instead of the composition 1. The total light transmittance of the composition 5 was measured based on the above < test method >, and the color difference of the laminated separator 5 for a nonaqueous electrolyte secondary battery was measured. The results are shown in table 1, table 2, and fig. 1 to 3.

[ example 6]

(1. preparation of coating solution)

An aramid resin was produced in the same manner as in example 1, except that the amount of 2-chloro-1, 4-phenylenediamine as the aromatic diamine added was changed to 8.63g, and the amount of TPC as the acid chloride added was changed to 11.96 g. An aramid resin 6 having a chlorine group as an electron-withdrawing group in the aromatic ring in the main chain, amino groups at both ends of the molecule, 100% of the bonds linking the aromatic rings contained in the main chain being an amide bond, 100% of the units derived from an aromatic diamine having an electron-withdrawing group, and units derived from an acid chloride having no electron-withdrawing group and having an intrinsic viscosity of 1.9dL/g was obtained.

Next, aramid resin 6, large-particle-size alumina and small-particle-size alumina as fillers, and NMP as a solvent were mixed to prepare composition 6 in which the total concentration of aramid resin 6 and fillers was 4 wt%. At this time, in order to set the content of the filler in the porous layer described later to 40 wt%, the aramid resin 6, the filler, and the solvent are mixed so that the content of the filler becomes 40 wt% when the weight of the aramid resin 6 and the filler is set to 100 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery, measurement of Total light transmittance and measurement of color Difference)

A laminated separator 6 for a nonaqueous electrolyte secondary battery was obtained in the same manner as in example 1, except that the composition 6 was used instead of the composition 1. The total light transmittance of composition 6 was measured based on the above < test method >, and the color difference of the laminated separator 6 for a nonaqueous electrolyte secondary battery was measured. The results are shown in table 1, table 2, and fig. 1 to 3.

[ example 7]

(1. preparation of coating solution)

An aramid resin was produced in the same manner as in example 1, except that the amount of 2-chloro-1, 4-phenylenediamine as the aromatic diamine added was changed to 8.63g, and the amount of TPC as the acid chloride added was changed to 11.96 g. An aramid resin 7 having a chlorine group as an electron-withdrawing group in the aromatic ring in the main chain, amino groups at both ends of the molecule, 100% of the bonds linking the aromatic rings contained in the main chain being an amide bond, 100% of the units derived from an aromatic diamine having an electron-withdrawing group, and units derived from an acid chloride having no electron-withdrawing group and having an intrinsic viscosity of 1.9dL/g was obtained.

Next, aramid resin 7, large-particle-size alumina and small-particle-size alumina as fillers, and NMP as a solvent were mixed to prepare composition 7 in which the total concentration of aramid resin 7 and fillers was 3 wt%. At this time, in order to set the content of the filler in the porous layer described later to 20 wt%, assuming that the weight of the aramid resin 7 and the filler is 100 wt%, the aramid resin 7, the filler, and the solvent are mixed so that the content of the filler becomes 20 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery, measurement of Total light transmittance and measurement of color Difference)

A laminated separator 7 for a nonaqueous electrolyte secondary battery was obtained in the same manner as in example 1, except that the composition 7 was used instead of the composition 1. The total light transmittance of the composition 7 was measured based on the above < test method >, and the color difference of the laminated separator 7 for a nonaqueous electrolyte secondary battery was measured. The results are shown in table 1, table 2, and fig. 1 to 3.

Comparative example 1

(1. preparation of composition)

An aramid resin was produced in the same manner as in example 1, except that p-phenylenediamine, which is an aromatic diamine, was 13.20g, and TPC, which is an aromatic dicarboxylic acid, was 24.18 g. A comparative aramid resin 1 having no electron-withdrawing group in the aromatic ring in the main chain, having amino groups at both ends of the molecule, wherein 100% of the bonds linking the aromatic rings in the main chain were amide bonds, and the units derived from the aromatic diamine and the units derived from the acid chloride had no electron-withdrawing groups, and had an intrinsic viscosity of 1.9dL/g was obtained.

Next, the aramid resin 1 for comparison, large-particle-size alumina and small-particle-size alumina as fillers, and NMP as a solvent were mixed to prepare a composition 1 for comparison. At this time, in order to set the content of the filler in the porous layer described later to 66 wt%, the aramid resin 1 for comparison, the filler, and the solvent were mixed so that the content of the filler became 66 wt% when the weight of the aramid resin 1 for comparison and the filler were set to 100 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery, measurement of Total light transmittance and measurement of color Difference)

A laminated separator 1 for a nonaqueous electrolyte secondary battery for comparison was obtained in the same manner as in example 1, except that the composition 1 for comparison was used instead of the composition 1. The total light transmittance of the comparative composition 1 was measured based on the above < test method >, and the color difference was measured using the laminated separator 1 for a nonaqueous electrolyte secondary battery for comparison. The results are shown in table 1, table 2, and fig. 1 to 3.

Comparative example 2

(1. preparation of composition)

Comparative composition 2 was prepared by mixing comparative aramid resin 1, small-particle-size alumina as a filler, and NMP as a solvent, wherein the total concentration of the comparative aramid resin 1 and the filler was 4 wt%. At this time, in order to set the content of the filler in the porous layer described later to 50 wt%, the comparative aramid resin 1, the filler, and the solvent were mixed so that the content of the filler became 50 wt% when the weight of the comparative aramid resin 1 and the filler was set to 100 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery, measurement of Total light transmittance and measurement of color Difference)

A laminated separator 2 for a nonaqueous electrolyte secondary battery for comparison was obtained in the same manner as in example 1, except that the composition 2 for comparison was used instead of the composition 1. The total light transmittance of the comparative composition 2 was measured based on the above < test method >, and the color difference was measured using the laminated separator 2 for a nonaqueous electrolyte secondary battery for comparison. The results are shown in table 1, table 2, and fig. 1 to 3.

Comparative example 3

(1. preparation of coating solution)

An aramid resin was produced in the same manner as in example 1, except that the amount of 2-chloro-1, 4-phenylenediamine as the aromatic diamine added was changed to 11.20g, and the amount of 4, 4' -oxybis (benzoyl chloride) as the acid chloride added was changed to 10.51 g. A comparative aramid resin 3 having a chlorine group as an electron-withdrawing group in the aromatic ring in the main chain, amino groups at both ends of the molecule, 66% of the bonds connecting the aromatic rings contained in the main chain being an amide bond, 100% of the units derived from the aromatic diamine having an electron-withdrawing group, and the units derived from the acid chloride having no electron-withdrawing group and having an intrinsic viscosity of 1.5dL/g was obtained.

Next, the aramid resin 3 for comparison, large-particle-size alumina and small-particle-size alumina as fillers, and NMP as a solvent were mixed to prepare a composition 3 for comparison having a total concentration of the aramid resin 3 for comparison and the fillers of 6 wt%. At this time, in order to set the content of the filler in the porous layer described later to 50 wt%, the aramid resin for comparison 3, the filler, and the solvent were mixed so that the content of the filler became 50 wt% when the weight of the aramid resin for comparison 3 and the filler was set to 100 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery, measurement of Total light transmittance and measurement of color Difference)

A laminated separator 3 for a nonaqueous electrolyte secondary battery for comparison was obtained in the same manner as in example 1, except that the composition 3 for comparison was used instead of the composition 1. The total light transmittance of the comparative composition 3 was measured based on the above < test method >, and the color difference was measured using the laminated separator 3 for a nonaqueous electrolyte secondary battery for comparison. The results are shown in table 1, table 2, and fig. 1 to 3.

Comparative example 4

(1. preparation of coating solution)

An aramid resin was produced in the same manner as in example 1, except that the amount of 4, 4' -diaminodiphenyl ether as the aromatic diamine added was 17.31g, and the amount of TPC as the acid chloride added was 17.38 g. A comparative aramid resin 4 having no electron-withdrawing group in the aromatic ring in the main chain, having amino groups at both ends of the molecule, 66% of the bonds linking the aromatic rings in the main chain being amide bonds, no electron-withdrawing group in the unit derived from an aromatic diamine, no electron-withdrawing group in the unit derived from an acid chloride, and an intrinsic viscosity of 1.7dL/g was obtained.

Next, the aramid resin 4 for comparison, large-particle-size alumina and small-particle-size alumina as fillers, and NMP as a solvent were mixed to prepare a composition 4 for comparison having a total concentration of the aramid resin 4 for comparison and the fillers of 6 wt%. At this time, in order to set the content of the filler in the porous layer described later to 50 wt%, the aramid resin 4 for comparison, the filler, and the solvent were mixed so that the content of the filler became 50 wt% when the weight of the aramid resin 4 for comparison and the filler were set to 100 wt%.

(2. preparation of laminated separator for nonaqueous electrolyte Secondary Battery, measurement of Total light transmittance and measurement of color Difference)

A laminated separator 4 for a nonaqueous electrolyte secondary battery for comparison was obtained in the same manner as in example 1, except that the composition 4 for comparison was used instead of the composition 1. The total light transmittance of the comparative composition 4 was measured based on the above < test method >, and the color difference was measured using the laminated separator 4 for a nonaqueous electrolyte secondary battery for comparison. The results are shown in table 1, table 2, and fig. 1 to 3.

[ TABLE 1]

[ TABLE 2]

In table 1, "main chain aromatic ring electron-withdrawing group" represents the kind of electron-withdrawing group contained in the aromatic ring in the main chain; the "diamine unit-attracting group content" represents the proportion of units having an electron-withdrawing group in units derived from an aromatic diamine in an aromatic polyamide resin; the "content ratio of acid chloride unit-attracting group" represents the proportion of units having an electron-attracting group among units derived from acid chloride in the aramid resin; "the presence or absence of a terminal amino group" indicates whether or not an amino group is present at the molecular terminal of the aramid resin (the presence of an amino group is indicated by "-"); "aromatic ring-linked amide ratio" means a ratio in which a bond linking aromatic rings contained in the main chain has an amide group; "filler content in the porous layer" means the content of the filler when the weight of the porous layer is 100 wt%; "intrinsic viscosity of aramid" means the intrinsic viscosity of the aramid resin.

In addition, fig. 1 is a graph obtained by plotting "total light transmittance of composition" in table 2; fig. 2 is a graph obtained by plotting "total light transmittance of laminated spacers" in table 2; fig. 3 is a graph of "color difference between defective portion and normal portion" in table 2. The total light transmittance of a value not more than the value indicated by the broken line in fig. 1 and 2 is preferable in easily inspecting the presence or absence of defects in the laminated separator for a nonaqueous electrolyte secondary battery.

As shown in tables 1 and 2 and fig. 1 and 2, the total light transmittance of the compositions 1 to 7 prepared in examples was very low, and therefore, the total light transmittance of the laminated spacers 1 to 7 for nonaqueous electrolyte secondary batteries prepared using the compositions was also low. Therefore, as shown in table 2 and fig. 3, the difference in color between the defective portions, i.e., the suspected defects in the examples and comparative examples, and the normal portions of the laminated spacers 1 to 7 for nonaqueous electrolyte secondary batteries was large. That is, it is known that the presence of a defect can be easily detected.

Industrial applicability

The composition and the like according to one embodiment of the present invention can be suitably used in various industries for handling nonaqueous electrolyte secondary batteries.