JP2019046683A - Composition for electrochemical element separator - Google Patents

Abstract

To provide a method for achieving a good balance between ion conductivity and strength in an electrochemical element separator.SOLUTION: A composition for an electrochemical element separator includes: an inorganic particle; and an organic binder having at least one group selected from the group consisting of a carboxy group, a carboxylate group that is a salt of a carboxy group, and a hydroxyl group. The composition further includes a polyvalent metal compound in which at least one of a solubility in water and a solubility in methanol is 3 g/100 mL or more.SELECTED DRAWING: None

Description

The present invention relates to a composition for a separator for an electrochemical device. More particularly, the present invention relates to a composition suitably used to form a separator for use in electrochemical devices such as batteries, capacitors, capacitors, sensors, and electrolysis devices.

In recent years, in many industries from small portable devices to large-sized applications such as automobiles, the importance of electrochemical devices including batteries is rapidly increasing, and they are superior mainly in terms of their capacity, energy density, and secondary batteries. Various new battery systems with different characteristics have been developed and improved.

Various developments and improvements have also been made for separators used in electrochemical devices, and for example, gel electrolytes having a cross-linked structure with multivalent ions and / or inorganic compounds used for battery separators and the like have been disclosed ( See, for example, Patent Document 1).

By the way, the action mechanism of zirconium ammonium carbonate used as a water resistant agent for paper coating and the application example in the paper industry are disclosed (for example, refer to Non-patent document 1).

Unexamined-Japanese-Patent No. 2014-29818

Yoshiki Mabuchi, Paper and paper technical co-op, Japan Institute of Paper and Pulp Technology, Vol. 52, No. 2, p. 184-191

The gel electrolyte described in Patent Document 1 has high cycle characteristics, rate characteristics, and coulombs, while suppressing morphological changes, dissolution, corrosion and passivation of electrode active materials such as shape change of electrode active materials and dendrites. It can be suitably used to form a storage battery that exhibits battery performance such as efficiency. On the other hand, since ion conductivity and strength are in a trade-off relationship, separators used in electrochemical elements such as batteries, capacitors, capacitors, sensors, and electrolyzers (hereinafter, also simply referred to as electrolyzers). There is room for further ingenuity to achieve both in a well-balanced manner.

This invention is made in view of the said present condition, and it aims at providing the method of making ion conductivity and intensity compatible in balance with good balance in the separator for electrochemical devices.

The inventor studied various methods for achieving both ion conductivity and strength in a well-balanced manner in the separator for an electrochemical element, and based on inorganic particles, a carboxy group, a carboxylate group which is a salt thereof, and a hydroxyl group. And an organic binder (organic bonding material) having at least one functional group selected from the group consisting of: at least one of solubility in water and solubility in methanol is at least 3 g / 100 mL. Prepared. The inventors of the present invention have found that, by using this composition for a separator for an electrochemical device, a separator for an electrochemical device having well balanced ion conductivity and strength can be obtained. The reason is that the soluble polyvalent metal compound forms a crosslinked structure between the inorganic particles and the organic binder in the composition during film formation, and the density between the inorganic particles and the organic binder is slightly expanded to reduce the density. It is thought that this is to strengthen the interaction. The present inventor has arrived at the present invention with the expectation that the above-mentioned problems can be solved in this way.

That is, the present invention provides a composition for a separator for an electrochemical device, which comprises inorganic particles, and an organic binder having at least one functional group selected from the group consisting of carboxy groups, carboxylates that are salts thereof, and hydroxyl groups. That is, the composition is a composition for a separator for an electrochemical element, further comprising a polyvalent metal compound having at least one of the solubility in water and the solubility in methanol of 3 g / 100 mL or more.

The separator for an electrochemical device of the present invention can balance ion conductivity and strength with good balance.

It is a perspective view which shows the apparatus of a puncture strength test typically. It is sectional drawing which shows the apparatus of a puncture strength test typically. It is an enlarged view of FIG.

The present invention will be described in detail below.
In addition, what combined two or more of each preferable form of this invention described below is also a preferable form of this invention.

<Composition for Separator for Electrochemical Device>
(Polyvalent metal compound)
The composition for a separator for an electrochemical device (hereinafter, also simply referred to as the composition) of the present invention contains a polyvalent metal compound in which at least one of the solubility in water and the solubility in methanol is 3 g / 100 mL or more.
The polyvalent metal compound having such solubility can form a crosslinked structure suitably between the inorganic particles and the organic binder and between the organic binder in the composition of the present invention.
Among polyvalent metal compounds, the solubility of the compound itself in water is low, but some compounds are hydrolyzed during solubility measurement to increase the solubility, and it may be difficult to appropriately measure the solubility in water. is there. In such a case in particular, instead of the solubility in water, it is possible not to cause hydrolysis and to be based on the solubility in methanol, which is a protic polar solvent similar to water.

At least one of the solubility in water and the solubility in methanol of the polyvalent metal compound is preferably 10 g / 100 mL or more, more preferably 20 g / 100 mL or more, and particularly preferably 40 g / 100 mL or more.
Further, at least one of the solubility in water and the solubility in methanol satisfies the above lower limit and is preferably 110 g / 100 mL or less, more preferably 100 g / 100 mL or less, and 90 g / 100 mL or less More preferable.
Among them, the polyvalent metal compound preferably has a solubility in water in the above solubility range.
In the present specification, solubility refers to solubility at 25 ° C. and 1 atm.

The valence of the polyvalent metal in the polyvalent metal compound may be at least divalent but is preferably, for example, 2 to 5 and more preferably 3 to 5.
The polyvalent metal in the polyvalent metal compound is not particularly limited as long as the valence is polyvalent (divalent or more), but it is preferably, for example, zirconium and / or titanium, and more preferably zirconium.

The polyvalent metal compound preferably has an oxygen atom and / or an atomic group having an oxygen atom, and the oxygen atom is preferably bonded to a metal.
As the above atomic group, carbonate group (CO ₃ group); hydroxy group; sulfate group (SO ₄ group); nitrate group (NO ₃ group); alkoxy group such as methoxy group, ethoxy group, propoxy group, butoxy group, etc .; Chelate groups such as acetonate group, octylene glycolate group, ethylacetoacetate group, acetate group, lactate group, acrylate group, methacrylate group and the like can be mentioned.
The polyvalent metal compound may further have a reactive group such as an amino group, an epoxy group, a mercapto group and an unsaturated hydrocarbon group, a hydrocarbon group, a halogen atom and the like.

Examples of the polyvalent metal compounds include inorganic salts of polyvalent metals such as zirconium ammonium carbonate, potassium zirconium carbonate, zirconium sulfate, zirconium nitrate, zirconium acetate, zirconium acetate, zirconium oxychloride, monohydroxy zirconium trilactate ammonium salt , Tetra-n-butoxyzirconium, titanium triethanolaminate, titanium dinormal butoxy-bis (triethanolaminate, titanium diisopropoxy-bis (triethanolaminate), titanium diisopropoxy-bis (acetylacetonate) And organic salts of polyvalent metals such as titanium lactate, titanium lactate ammonium salt, etc., among which zirconium ammonium carbonate, zirconium potassium carbonate, oxychloride Rukoniumu, titanium lactate, titanium lactate ammonium salt particularly preferred.

In the composition of the present invention, the content of the polyvalent metal compound is preferably 0.2 to 15% by mass in 100% by mass of the composition. If the content of the polyvalent metal compound is less than 0.2% by mass, the effects of the present invention may not be sufficiently exhibited. If the content of the polyvalent metal compound exceeds 15% by mass, the composition may be gelled.
The content of the polyvalent metal compound is more preferably 0.3% by mass or more, and still more preferably 0.4% by mass or more. The content of the polyvalent metal compound is more preferably 14% by mass or less, still more preferably 13% by mass or less, and particularly preferably 12% by mass or less.

(Organic binder)
The organic binder has at least one functional group selected from the group consisting of a carboxy group, a carboxylate group which is a salt thereof, and a hydroxyl group. The carboxylate group is not particularly limited as long as it is a salt of a carboxy group, and for example, metal salts, ammonium salts and organic amine salts are preferable. Examples of the metal salt include sodium salt, calcium salt, magnesium salt and the like. The organic binder can preferably form a crosslinked structure with the inorganic particles through the polyvalent metal compound by having the above-mentioned functional group (reactive group).

As the organic binder, various ones can be used as long as they have the above-mentioned functional group, and any of thermoplasticity and thermosetting may be used. For example, carboxy modified conjugated diene based polymer; carboxy modified polyolefin based polymer (Meth) acrylic polymers having at least one functional group selected from the group consisting of a carboxy group, a carboxylate group which is a salt thereof, and a hydroxyl group; polyvinyl alcohol; ethylene-vinyl alcohol copolymer etc. suitable These can be used alone or in combination of two or more. Here, the term "carboxy modification" refers to having a carboxy group and / or a carboxylate group which is a salt thereof, and hereinafter, a carboxy group and / or a carboxylate group which is a salt thereof is a carboxy group It may be expressed as degeneration. These organic binders may be further crosslinked by a known organic crosslinking agent compound. In other words, the composition of the present invention has at least one functional group selected from the group consisting of a carboxy-modified conjugated diene polymer, a carboxy-modified polyolefin, a carboxy group, a carboxylate which is a salt thereof, and a hydroxyl group. It is preferable to include at least one selected from the group consisting of (meth) acrylic polymers, polyvinyl alcohol, and ethylene-vinyl alcohol copolymers.

The above-mentioned carboxy modified conjugated diene type polymer should just have a carboxylate group which is a carboxy group and / or its salt with a monomer unit derived from a conjugated diene type monomer, for example, has a monomer unit derived from a conjugated diene type monomer Further, those having a monomer unit derived from an unsaturated monomer having a carboxy group and / or a carboxylate group which is a salt thereof are preferably mentioned.

The unsaturated monomer having a carboxyl group which is the above-mentioned carboxy group and / or a salt thereof is an unsaturated monocarboxylic acid (salt) such as (meth) acrylic acid (salt); maleic acid (salt), fumaric acid (salt) And unsaturated dicarboxylic acids (salts) such as itaconic acid (salts) and the like, and these may be used alone or two or more kinds may be used in combination.

The mass ratio of monomer units derived from unsaturated monomers having a carboxy group and / or a carboxylate group which is a salt thereof is 0.2, from the viewpoint of making the strength of the separator more excellent in the carboxy-modified conjugated diene polymer. It is preferable that it is mass% or more, It is more preferable that it is 0.3 mass% or more, It is still more preferable that it is 0.5 mass% or more. Moreover, from the viewpoint of making the ion conductivity of the separator more excellent, the mass ratio is preferably 10% by mass or less, more preferably 8% by mass or less, and 5% by mass or less More preferable.

The conjugated diene-based monomer is preferably an aliphatic conjugated diene-based monomer. As an aliphatic conjugated diene type monomer, a 1, 3- butadiene, an isoprene, 2-chloro- 1, 3- butadiene, a chloroprene etc. are mentioned, for example, Especially, a 1, 3- butadiene is preferable. The conjugated diene monomers may be used alone or in combination of two or more.

As the carboxy-modified conjugated diene-based polymer, a monomer unit derived from an unsaturated monomer having a carboxy group and / or a carboxylate group which is a salt thereof, and a monomer unit derived from a conjugated diene-based monomer are used alone or in combination of two or more However, from the viewpoint of enhancing the uniformity of the composition of the present invention and the mechanical strength of the obtained separator and suitably controlling the elongation and stress, for example, monomer units derived from an aromatic vinyl monomer can be obtained. Furthermore, it is preferable to have.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene and o-methoxystyrene , M-methoxystyrene, p-methoxystyrene, o-ethoxystyrene, m-ethoxystyrene, p-ethoxystyrene, o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, o-chlorostyrene, m-chlorostyrene P-chlorostyrene, o-bromostyrene, m-bromostyrene, p-bromostyrene, o-acetoxystyrene, m-acetoxystyrene, p-acetoxystyrene, o-tert-butoxystyrene, m-tert-butoxystyrene, p-tert-butoxys Ren, o-tert-butylstyrene, m-tert-butylstyrene, p-tert-butylstyrene and vinyltoluene. Among these, styrene and α-methylstyrene are preferable in that the heat resistance and mechanical strength of the separator can be increased, and the elongation and stress are suitably controlled. These aromatic vinyl monomers may be used alone or in combination of two or more.

The carboxy-modified conjugated diene polymer preferably has a mass ratio of a monomer unit derived from an aliphatic conjugated diene monomer to a monomer unit derived from an aromatic vinyl monomer, for example, 1/9 or more and 9/1 or less It is more preferably 2/8 or more and 8/2 or less, and still more preferably 3/7 or more and 7/3 or less.

As the carboxy-modified conjugated diene polymer, one or more of a carboxy-modified styrene-butadiene polymer, a carboxy-modified polybutadiene polymer, a carboxy-modified polyisoprene polymer, and a carboxy-modified acrylonitrile-butadiene polymer are suitably used. be able to. Among these, carboxy modified styrene-butadiene type polymer and carboxy modified acrylonitrile-butadiene type polymer are preferable, and especially carboxy modified styrene-butadiene type polymer is preferable.

The carboxy-modified conjugated diene-based polymer is a monomer unit derived from an unsaturated monomer having a carboxy group and / or a carboxylate group which is a salt thereof, a monomer unit derived from an aliphatic conjugated diene-based monomer, a monomer unit derived from an aromatic vinyl monomer It may have monomer units derived from other unsaturated monomers other than the above.

As other unsaturated monomers, for example, sulfonic acid group-containing vinyl monomers such as acrylamidomethylpropane sulfonic acid, styrene sulfonate, etc .; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (Meth) acrylic acid n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid t-butyl, (meth) acrylic acid pentyl, (meth) acrylic acid hexyl, (meth) acrylic acid heptyl, (meth) acrylic (Meth) acrylic acid ester monomers such as octyl acid octyl, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate and decyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid Hydroxyl-containing vinyl monomers such as 4-hydroxybutyl, (meth) ac Nitrile group-containing vinyl monomers such as ronitrile, (meth) acrylamides, N-methylol (meth) acrylamides, N-ethylol (meth) acrylamides, dimethyl (meth) acrylamides, (meth) acrylamide monomers such as diethyl (meth) acrylamides, Bifunctional vinyl monomers such as divinylbenzene, ethylene glycol dimethacrylate, isopropylene glycol diacrylate, tetramethylene glycol dimethacrylate; 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltritriol There can be mentioned alkoxysilane group-containing vinyl monomers such as ethoxysilane.

The proportion by mass of monomer units derived from other unsaturated monomers is preferably 30% by mass or less, more preferably 5% by mass or less, and more preferably 0.1% by mass or less in 100% by mass of the carboxy-modified conjugated diene polymer Is more preferred.

The above-mentioned carboxy-modified polyolefin polymer may be any one having a carboxy group and / or a carboxylate group which is a salt thereof together with a monomer unit derived from unsaturated hydrocarbon, for example, having a monomer unit derived from unsaturated hydrocarbon Further, those having a monomer unit derived from an unsaturated monomer having a carboxy group and / or a carboxylate group which is a salt thereof, a carboxyl group and / or a salt thereof by graft-modifying a polyolefin with an organic peroxide or the like And the like. Among them, those having a monomer unit derived from unsaturated hydrocarbon and further having a carboxyl group and / or a carboxylate group being a salt thereof which is a salt thereof are more preferable. Those having a monomer unit are preferred.

The type of unsaturated monomer having a carboxy group and / or a carboxylate group which is a salt thereof, and the preferable content of a monomer unit derived from the monomer are as described above in the carboxy-modified conjugated diene-based polymer.

Examples of the unsaturated hydrocarbon include ethylene, propylene, 1-butene, 1-hexene, 1-pentene, isoprene, diisobutylene, 1-heptene, 1-octene, 1-nonene, 1-undecene, 1-dodecene, 1 -Tridecene, 1-tetradecene, 1-pentadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, trimers and tetramers of propylene, terminal olefins such as styrene, vinyl toluene, divinylbenzene, etc. 2-butene Intramolecular olefins such as 2-octene, 2-methyl-1-hexene, 2,3-dimethyl-2-butene and the like may be mentioned, and these may be used alone or in combination of two or more.

The carboxy-modified polyolefin polymer is a monomer unit derived from an unsaturated monomer having a carboxy group and / or a carboxylate which is a salt thereof, a monomer unit derived from another unsaturated monomer other than a monomer unit derived from an unsaturated hydrocarbon May be included.

As other unsaturated monomers, the same as those described above in the above-mentioned carboxy-modified conjugated diene-based polymer can be mentioned.
The proportion by mass of monomer units derived from other unsaturated monomers is preferably 30% by mass or less, more preferably 5% by mass or less, and more preferably 0.1% by mass or less in 100% by mass of the carboxy-modified polyolefin polymer. More preferable.

The (meth) acrylic polymer having at least one functional group selected from the group consisting of the above carboxy group, a carboxylate group which is a salt thereof, and a hydroxyl group is a monomer unit derived from a monomer having a (meth) acryloyl group. As long as it has at least one functional group selected from the group consisting of a carboxy group, a carboxylate group which is a salt thereof, and a hydroxyl group, for example, polyacrylic acid (salt), a carboxy group Examples thereof include (meth) acrylic acid ester-based polymers having at least one functional group selected from the group consisting of carboxylate groups, which are salts, and hydroxyl groups.

The (meth) acrylic acid ester-based polymer having at least one functional group selected from the group consisting of the above carboxy group, a carboxylate group which is a salt thereof, and a hydroxyl group is a monomer unit derived from a (meth) acrylic acid ester monomer In addition, it is sufficient if it has at least one functional group selected from the group consisting of a carboxy group, a carboxylate group which is a salt thereof, and a hydroxyl group, and specifically, (meth) acrylic acid A monomer unit derived from an ester monomer as a main component, and further, a monomer unit derived from an unsaturated monomer having a carboxy group and / or a carboxylate group which is a salt thereof and / or a monomer unit derived from an unsaturated monomer having a hydroxyl group The thing is mentioned.

Examples of the unsaturated monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate. One or more of these can be used.
The unsaturated monomer having a carboxy group and / or a carboxylate group which is a salt thereof, (meth) acrylic acid ester monomer is as described above in the carboxy-modified conjugated diene-based polymer.
The content of monomer units derived from (meth) acrylic acid ester monomers is 50% by mass or more in 100% by mass of (meth) acrylic acid ester-based polymers, based on the monomer units derived from (meth) acrylic acid ester monomers as main components Say something.

The polyvinyl alcohol is a polymer obtainable by saponifying polyvinyl acetate, and one having a degree of saponification of 100 mol% is represented by a general formula [CH ₂ CH (OH)] _n . The average degree of polymerization n of polyvinyl alcohol is not particularly limited, but is preferably, for example, 300 to 5,000.
The average degree of polymerization n can be calculated by the method described in JIS K6726.
The average degree of saponification is preferably 50 to 100 mol%, more preferably 80 to 100 mol%, and still more preferably 90 to 100 mol%.
The average degree of saponification can be measured by the method described in JIS K6726.

The ethylene-vinyl alcohol copolymer contains an ethylene-derived monomer unit and a vinyl alcohol-derived monomer unit. The mass ratio of the monomer unit derived from ethylene to the monomer unit derived from vinyl alcohol is, for example, preferably 1/9 to 9/1, and more preferably 2/8 to 8/2. More preferably, it is 3/7 or more and 7/3 or less.

The ethylene-vinyl alcohol copolymer may have monomer units derived from other unsaturated monomers other than ethylene-derived monomer units and vinyl alcohol-derived monomer units. Other unsaturated monomers include those described above for carboxy modified conjugated diene based polymers. In 100% by mass of the ethylene-vinyl alcohol copolymer, the mass ratio of monomer units derived from other unsaturated monomers is preferably 5% by mass or less, more preferably 1% by mass or less, 0.2% by mass The following is more preferable. Further, it is particularly preferable that the ethylene-vinyl alcohol copolymer does not have monomer units derived from other unsaturated monomers.

By selecting the type of the organic binder contained in the composition of the present invention, the elongation and stress can be appropriately adjusted. For example, it is particularly preferable that the composition of the present invention includes at least one selected from the group consisting of a carboxy-modified conjugated diene polymer, a carboxy-modified polyolefin polymer, and a polyvinyl alcohol, whereby the elongation percentage and the stress It can be adjusted very well.

It is preferable that the glass transition temperature (Tg) of the said organic binder is -40 degreeC or more and 100 degrees C or less. If the Tg of the polymer is less than -40 ° C, the strength of the separator may be insufficient. When the Tg of the polymer exceeds 100 ° C., the separator is too hard and brittle, and the separator may be cracked or the like when the battery is formed, which may lower the life performance of the battery. When the Tg of the polymer is −40 ° C. or more and 100 ° C. or less, the kneaded product at the time of kneading with other components has appropriate fluidity, and the components contained in the separator forming material can be made more uniform. it can. The Tg of the polymer is more preferably -35 ° C or more and 50 ° C or less, and still more preferably -30 ° C or more and 30 ° C or less.
The Tg of a polymer can be measured by differential scanning calorimetry.

The organic binder can be produced by copolymerizing a monomer component that forms a structural unit contained in a polymer in the presence of a radical generator, and graft-modifying this as necessary.
The method for polymerizing the monomer component is not particularly limited, and examples thereof include methods such as an aqueous solution polymerization method, an emulsion polymerization method, a reverse phase suspension polymerization method, a suspension polymerization method, a solution polymerization method and a bulk polymerization method.

The mass ratio of the organic binder is preferably 5% by mass or more, and 7% by mass in 100% by mass of the composition, from the viewpoint of ion conductivity of the separator or from the viewpoint of suitably adjusting the elongation and stress of the separator. It is more preferable that it is the above, and from a viewpoint of making the intensity | strength of a separator more excellent, it is still more preferable that it is 10 mass% or more. The mass ratio is preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less, and particularly preferably 40% by mass or less.

(Inorganic particles)
The composition of the present invention further comprises inorganic particles. The inorganic particles are preferably at least one selected from the group consisting of, for example, oxides, hydroxides, layered double hydroxides, and phosphoric acid compounds. In addition, in this specification, a hydroxide is a compound which has a hydroxyl group, Comprising: It says things other than layered double hydroxide.

Examples of the oxide include lithium oxide, sodium oxide, potassium oxide, magnesium oxide, calcium oxide, barium oxide, scandium oxide, yttrium oxide, lanthanoid oxide, titanium oxide, zirconium oxide, niobium oxide, ruthenium oxide, nickel oxide, And palladium oxide, copper oxide, cadmium oxide, boron oxide, aluminum oxide, gallium oxide, indium oxide, thallium oxide, silicon oxide, germanium oxide, tin oxide, lead oxide, phosphorus oxide, bismuth oxide, etc. Or two or more types can be used. Among them, the composition at the time of film formation and the one which is stable even under alkaline conditions in the electrochemical element are preferable. For example, magnesium oxide, calcium oxide, titanium oxide, zirconium oxide and aluminum oxide are preferable, magnesium oxide and titanium oxide And zirconium oxide are more preferred. The zirconium oxide may be, for example, a solid solution of an element such as yttrium, scandium, ytterbium or the like, or may have an oxygen defect.

Examples of the hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, scandium hydroxide, yttrium hydroxide, lanthanoid hydroxide, titanium hydroxide, water Zirconium oxide, niobium hydroxide, ruthenium hydroxide, nickel hydroxide, palladium hydroxide, copper hydroxide, cadmium hydroxide, boric acid, aluminum hydroxide, gallium hydroxide, indium hydroxide, thallium hydroxide, silicic acid, water Germanium oxide, tin hydroxide, lead hydroxide, phosphoric acid, bismuth hydroxide and the like can be mentioned, and one or more of these can be used. Among them, those having low solubility under alkaline conditions are preferable. For example, magnesium hydroxide, calcium hydroxide, titanium hydroxide and zirconium hydroxide are preferable, and magnesium hydroxide is more preferable.

The above layered double hydroxide has the following general formula:
[M ¹ _1-x M ² _x (OH) ₂ ] (A ^{n −} ) _{x / n} · _m H ₂ O
(M ¹ represents a divalent metal ion which is any of Mg, Fe, Zn, Ca, Li, Ni, Co, Cu, and Mn. M ² is Al, Fe, Mn, Co, Cr, In A ^n- represents a monovalent or more or trivalent anion such as Cl ⁻ , NO ₃ ⁻ , CO ₃ ²⁻ , COO ^−, etc. Among them, A ⁿ⁻ is an anion of any of trivalent metal ions. It is preferable to represent a divalent or less anion, m is a number of 0 or more, n is a number of 1 or more and 3 or less, and x is a number of 0.20 or more and 0.40 or less.) Examples of such layered double hydroxides include hydrotalcite, manasseite, mozcoleite, stichtite, shogrenite, barovertite, pyroaurite, iomite, chloromagalminite, hydrophoric compound, and the like. Karma And Green Last 1, Bercherine, Tacobite, Ribesite, Honesite, Yardite, Meikisenelite, etc., and one or more of these can be used. Among them, hydrotalcites in which M ¹ in the above general formula is Mg and M ² is Al are preferable in that they are industrially easy to use.
In these layered hydroxides, for example, compounds dehydrated by firing at 150 ° C. or more and 900 ° C. or less, compounds obtained by decomposing anions in the layer, anions in the layer to hydroxide ions, etc. It may be a exchanged compound.
The layered double hydroxide may be coordinated with a compound having a functional group such as a hydroxyl group, an amino group, a carboxy group or a silanol group. Further, the layered double hydroxide may have an organic matter in the interlayer.

As the above-mentioned phosphoric acid compound, for example, hydroxyapatite (Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ), magnesium hydroxyapatite in which a part or all of calcium ions of hydroxyapatite is substituted by magnesium, strontium hydroxyapatite substituted by strontium And barium hydroxyapatite substituted with barium. Among them, hydroxyapatite and magnesium hydroxyapatite are preferable.

Among the above, the inorganic particles are more preferably layered double hydroxides and / or hydroxides. From the viewpoint of making the strength of the separator more excellent, the inorganic particles are further preferably a hydroxide, and from the viewpoint of making the ion conductivity of the separator more excellent, a layered double hydroxide It is further preferred that

The inorganic particles are in the form of particles, and examples of the shape thereof include fine powder, powder, granules, granules, scaly, polyhedrons, rods, curved surfaces, and the like.
The inorganic particles preferably have an average particle size of 5 μm or less. The average particle size is more preferably 2 μm or less, still more preferably 1 μm or less. The average particle diameter is preferably 0.001 μm or more, more preferably 0.01 μm or more, and still more preferably 0.1 μm or more.
The average particle size may be any of the average particle sizes of the inorganic particle powder or the inorganic particle dispersion before being mixed with other components to obtain the composition of the present invention, as described in the Examples. It can be measured according to the method.

The particles having an average particle diameter in the range as described above are, for example, a method of pulverizing the particles with a ball mill or the like, dispersing the obtained coarse particles in a dispersing agent to obtain a desired particle diameter, and drying. The coarse particles can be sieved or the like to select the particle size, and the preparation conditions can be optimized at the stage of producing the particles to produce (nano) particles having a desired particle size.

The mass ratio of the inorganic particles is preferably 30% by mass or more in 100% by mass of the composition of the present invention, from the viewpoint of improving the strength of the separator and the ion conductivity. The mass ratio is more preferably 50% by mass or more, still more preferably 60% by mass or more, and from the viewpoint of making the ion conductivity of the separator more excellent, it is more preferably 70% by mass or more . Moreover, it is preferable that this mass ratio is 95 mass% or less. The mass fraction is more preferably 90% by mass or less.

(Other ingredients)
The composition of the present invention may contain a water-soluble polymer as a dispersant for inorganic particles and the like.
Examples of the water-soluble polymer include celluloses such as carboxymethylcellulose; poly (meth) acrylic acid (salts) such as sodium polyacrylate; and the like. One or more of these can be used.

When the composition of the present invention contains a water-soluble polymer, the content ratio of the water-soluble polymer may be adjusted as appropriate, but from the viewpoint of sufficiently dispersing the inorganic particles to exhibit the function and effect, the composition of the present invention It is preferable that it is 0.05 mass% or more in 100 mass%, and it is more preferable that it is 0.1 mass% or more. The content ratio is preferably 4% by mass or less, and 2% by mass or less from the viewpoint of further suppressing the plasticization of the separator by absorbing the electrolytic solution such as water by the water-soluble polymer. Is more preferred.

The composition of the present invention may further contain other inorganic components such as conductive carbon and conductive ceramics.
The content ratio of the other inorganic components in the composition of the present invention is preferably 1% by mass or less in 100% by mass of the separator from the viewpoint of the strength of the separator. More preferably, it is 0.5 mass% or less, More preferably, it is 0.2 mass% or less.

(Method of preparing the composition of the present invention)
As a method of preparing the composition of the present invention, for example, the following methods may be mentioned.
Raw materials (polyvalent metal compound, organic binder, and inorganic particles [dispersion]) of the composition of the present invention are mixed. For mixing, a mixer, blender, kneader, sand mill, bead mill, ready mill, roll mill, ball mill, etc. can be used. At the time of mixing, water, an organic solvent such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, tetrahydrofuran, N-methylpyrrolidone or the like, or a mixed solvent of water and an organic solvent may be added as a medium.
After mixing, filtration, degassing and the like may be performed as necessary to obtain the composition of the present invention.
In addition, you may manufacture an inorganic particle dispersion before mixing. For example, inorganic particles, and, if necessary, a dispersant for the inorganic particles, etc. are mixed. By producing the inorganic particle dispersion before mixing, it is possible to suppress the reaction of the polyvalent metal compound or the destabilization of the organic binder during the preparation. For mixing, the devices and media described above can be used.

The content of the medium in the composition of the present invention is preferably 20% by mass or more and 70% by mass or less in 100% by mass of the composition of the present invention from the viewpoint of suppressing film contraction during molding. The content ratio is more preferably 30% by mass or more and 60% by mass or less.
In addition, when the said organic binder and inorganic particle which are the raw materials of the composition for separators for electrochemical elements are the forms of a dispersion or a solution, the dispersion medium or solvent which is making the organic binder and inorganic particle disperse | distribute Also in the medium.
The content ratio of the medium can be calculated by determining the non-volatile content of the composition of the present invention by the method of the example.

The composition of the present invention is used to form a film to obtain an electrochemical device separator.

<Separator for electrochemical device>
The present invention is also a separator for an electrochemical device, which is characterized by using the composition for a separator for an electrochemical device of the present invention. In the present specification, the separator for electrochemical devices is also simply referred to as a separator.

The separator of the present invention preferably has an average film thickness of 10 μm to 1 mm. When the thickness is 10 μm or more, the occurrence of damage at the time of film formation can be sufficiently prevented. Further, if it is 1 mm or less, it is advantageous from the viewpoint of cost and the ability to transmit ions is also sufficiently excellent. The average film thickness is more preferably 20 μm or more, still more preferably 30 μm or more, and particularly preferably 40 μm or more. The average film thickness is more preferably 800 μm or less, still more preferably 500 μm or less, and particularly preferably 200 μm or less.
The average film thickness can be measured according to the method described in the examples.

The separator of the present invention preferably has a density of 0.7 to 2.0 g / cm ³ . As a result, the separator of the present invention more fully satisfies the basic performance required of the separator, and can be suitably used as the separator. The density is more preferably 0.8 g / cm ³ or more, still more preferably 0.9 g / cm ³ or more, and particularly preferably 1.0 g / cm ³ or more. Moreover, said seal degree, more preferably 1.9 g / cm ³ or less, further preferably 1.8 g / cm ³ or less, particularly preferably 1.7 g / cm ³ or less.
The density can be measured according to the method described in the examples.

The method for producing the separator of the present invention can include, for example, the steps of preparing the composition of the present invention described above, and molding the obtained composition into a film.

The method of producing a film from the composition of the present invention is not particularly limited as long as the film is formed, and a method of applying the composition of the present invention and drying it, and peeling the obtained coating film to obtain a film ( Casting method), rolling by roll to form a film, rolling by a flat plate press to form a film, or injection molding, extrusion molding, etc. it can. These molding methods may be used alone or in combination of two or more.
Thus, a method for producing a separator, for example, a separator composition for an electrochemical device containing the polyvalent metal compound according to the present invention, an organic binder, and inorganic particles, and optionally containing other components, is formed into a film. A method of manufacturing a separator including a forming step is also one of the present invention.

The above-mentioned production method preferably includes the step of drying the film during and / or after the step of forming the composition of the present invention into a film.
The drying step after the film formation may be carried out by heating the film, if necessary. The heating temperature and heating time of the film may be set appropriately.
The separator of the present invention may contain a porous support in addition to the composition of the present invention. Examples of the porous support include polyolefin resins such as polyethylene, polypropylene, ethylene-propylene copolymer and cyclic polyolefin resin; acrylic resins; styrene resins; polyester resins; polyamide resins; polyvinyl alcohol such as vinylon Non-woven fabrics, woven fabrics, microporous films and the like made of resin materials such as resins may be mentioned. The porous support may be subjected to a hydrophilization treatment by a conventionally known method. The porous support is preferably a polyvinyl alcohol resin or a material subjected to a hydrophilization treatment. In these porous supports, due to the introduction of a hydroxyl group or a carboxy group on the surface, a bond with the composition of the present invention is formed via a polyvalent metal compound, and the separator has more excellent strength. Become.
When the separator of the present invention includes a porous support, it is a laminate in which the composition of the present invention is laminated on the porous support. In the laminate, the composition of the present invention may fill part or all of the pores in the porous support.

The separator of the present invention is for use as a separator used in electrochemical devices such as batteries, capacitors, capacitors, sensors, and electrolytic devices.

<Electrochemical device>
The present invention is also an electrochemical device comprising the separator for an electrochemical device of the present invention.
In the electrochemical device of the present invention, only the separator of the present invention may be used as a separator, or another separator may be used in combination, for example, by laminating the separator of the present invention.
Other separators include nonwoven fabric, filter paper, polyolefin resin such as polyethylene and polypropylene, fluorine atom-containing resin such as polytetrafluoroethylene and polyvinylidene fluoride, cellulose, fibrillated cellulose, viscose rayon, cellulose acetate, hydroxyalkyl cellulose, Aryl group-containing resins such as carboxymethyl cellulose, polyvinyl alcohol and polystyrene, polyacrylonitrile resins, polyacrylamide resins, polyamide resins, polyimide resins, (meth) acrylic resins, hydroxyl group-containing resins such as polyisoprene and poly (meth) allyl alcohol, Polycarbonate resin, polyester resin, polyurethane resin, agar, organic-inorganic composite resin, ion exchange resin, sulfonate-containing resin, quaternary ammonium salt-containing tree , Quaternary phosphonium salts containing resins, cycloolefin polymers, film made of an inorganic substance such as a ceramic or the like. One or more of these separators may be used.
Among them, in the electrochemical device of the present invention, it is preferable to use only the separator of the present invention as a separator.

Examples of the electrochemical device of the present invention include batteries; capacitors such as electrolytic capacitors; capacitors such as electric double layer capacitors and lithium ion capacitors; sensors such as humidity sensors and gas sensors; and electrolytic devices such as alkaline water electrolytic devices .

The case where the electrochemical device of the present invention is a battery will be described in detail below.
The battery usually further comprises a positive electrode. As an active material of a positive electrode, what is normally used can be used as a positive electrode active material of a primary battery or a secondary battery, Although it does not restrict | limit in particular, For example, when oxygen (oxygen becomes a positive electrode active material, a positive electrode is oxygen Compounds capable of reduction of water and oxidation of water, cobalt-containing compounds, iron-containing compounds, copper-containing compounds, manganese-containing compounds, vanadium-containing compounds, nickel-containing compounds, iridium-containing compounds, platinum-containing compounds; palladium-containing compounds; Containing compound; silver containing compound; becoming an air electrode composed of carbon containing compound etc .; nickel containing compound such as nickel oxyhydroxide, nickel hydroxide, cobalt containing nickel hydroxide; manganese containing compound such as manganese dioxide; Silver; lithium-containing compounds such as lithium cobaltate; iron-containing compounds; metallic zinc and zinc oxide Examples include zinc species such as lead.
In addition, it is also one of the preferred embodiments of the present invention that the positive electrode active material is oxygen, such as an air battery.

The above-mentioned battery is usually constituted further including a negative electrode. As an active material of a negative electrode, what is normally used as a negative electrode active material of a battery, such as carbon, lithium, sodium, magnesium, zinc, nickel, tin, cadmium, a hydrogen storage alloy, a silicon containing material, can be used. For example, the present invention can be suitably applied to a battery using an active material which may generate dendrites as a negative electrode active material such as zinc, lithium, nickel, magnesium, cadmium, etc. .

An electrode such as a positive electrode or a negative electrode constituting the battery can be manufactured by forming an active material layer on a current collector.
As current collectors constituting the electrode, (electrolytic) copper foil, copper mesh (expanded metal), foamed copper, punched copper, copper alloy such as brass, brass foil, brass mesh (expanded metal), foamed brass, punched brass , Nickel foil, corrosion resistant nickel, nickel mesh (expanded metal), punching nickel, metallic zinc, corrosion resistant metal zinc, zinc foil, zinc mesh (expanded metal), (punching) steel plate, non-woven fabric imparted with conductivity; Ni · Zn · Copper foils such as Sn, Pb, Hg, Bi, In, Tl, brass, etc. (electrolytic), copper mesh (expanded metal), foamed copper, punched copper, brass, brass foil, brass mesh (expanded metal) ) · Foamed brass · Punching brass · Nickel foil · Corrosion resistant nickel · Nickel mesh (expanded Tal) · Punching nickel · Zinc metal · Corrosion resistant metal zinc · Zinc foil · Zinc mesh (expanded metal) · (Punching) steel plate · Non-woven fabric; plated with Ni · Zn · Sn · Pb · Hg · Bi · In · Tl · brass etc (Electrolytic) copper foil, copper mesh (expanded metal), foamed copper, punched copper, brass etc. copper alloy, brass foil, brass mesh (expanded metal), foamed brass, punched brass, nickel foil, corrosion resistant nickel, nickel Mesh (expanded metal), punching nickel, zinc metal, corrosion resistant metal zinc, zinc foil, zinc mesh (expanded metal), (punching) steel plate, non-woven fabric; silver; current collector or container for alkaline (storage) battery or air zinc battery And the like.

The electrolyte constituting the battery is not particularly limited as long as it is usually used as a battery electrolyte, and examples thereof include a water-containing electrolyte, an organic solvent-based electrolyte and the like. The water-containing electrolytic solution may be an electrolytic solution (water-based electrolytic solution) using only water as an electrolytic solution raw material, and a solution obtained by adding an organic solvent used in an organic solvent-based electrolytic solution to water is used as an electrolytic solution raw material It may be an electrolytic solution to be used. Examples of the organic solvent used for the organic solvent-based electrolytic solution include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, dimethoxymethane, diethoxymethane, dimethoxyethane, tetrahydrofuran, methyltetrahydrofuran, diethoxyethane, Dimethyl sulfoxide, sulfolane, acetonitrile, benzonitrile, ionic liquid, fluorine-containing carbonates, fluorine-containing ethers, polyethylene glycols, fluorine-containing polyethylene glycols, etc. may be mentioned, and one or more of them may be used. Can. The electrolyte of the organic solvent-based electrolytic solution is not particularly limited, but LiPF ₆ , LiBF ₄ , LiB (CN) ₄ , lithium bis (fluorosulfonyl) imide (LiFSI), lithium bis (trifluoromethylsulfonyl) imide LiTFSI) and the like, and one or more of these can be used.

Among them, the battery of the present invention is preferably a battery including a water-containing electrolytic solution. Where the water-containing electrolyte solution is more likely to be plasticized at the time of immersion of the separator, this can be sufficiently suppressed by the separator of the present invention, and the life of the battery can be prolonged. Moreover, the effect in an ion conduction surface can be anticipated by this.
When the electrolytic solution is a water-containing electrolytic solution containing an organic solvent-based electrolytic solution, the content of the aqueous electrolytic solution is preferably 10% by mass or more based on 100% by mass in total of the aqueous electrolytic solution and the organic solvent-based electrolytic solution. More preferably, it is 20 mass% or more, More preferably, it is 50 mass% or more. The upper limit value of the content of the aqueous electrolyte solution is not particularly limited, and may be 99.9 mass%, for example.

The water-containing electrolyte is preferably a water-based electrolyte. The aqueous electrolyte is preferably an alkaline electrolyte. Examples of the alkaline electrolyte include aqueous potassium hydroxide solution, aqueous sodium hydroxide solution, aqueous lithium hydroxide solution, aqueous zinc sulfate solution, aqueous zinc nitrate solution, aqueous zinc phosphate solution, aqueous zinc acetate solution and the like, and these may be used alone. It can also be used as an aqueous solution in which two or more of these solutes are mixed.

The form of the battery is usually a secondary battery (storage battery) that can be charged and discharged. In addition, the battery of the present invention utilizes mechanical charge (mechanical replacement of zinc negative electrode) in addition to general secondary batteries; battery using third electrode (electrode suitable for charge as positive electrode, It may be in any form such as one using an electrode suitable for discharge.

EXAMPLES The present invention will be described in more detail by way of the following examples, but the present invention is not limited to these examples. In addition, unless there is particular notice, "part" shall mean "weight part" and "%" shall mean "mass%."

<Average particle size of inorganic particles (powder)>
Particle size distribution measuring instrument by dynamic light scattering method about inorganic particle dispersion liquid which mixed inorganic particles (powder) and 0.2 mass% sodium hexametaphosphate aqueous solution, and performed dispersion processing using an ultrasonic cleaning machine ( Trade name: FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.), and the average particle diameter obtained by the cumulant analysis was taken as the average particle diameter of the inorganic particles.

<Non-volatile content of inorganic particle dispersion, organic binder aqueous dispersion and composition dispersion for film formation>
An inorganic particle dispersion, an organic binder aqueous dispersion, or 1 g of a composition dispersion for film formation is weighed, dried at a temperature of 110 ° C. for 1 hour using a hot air drier, and the obtained residue is regarded as a nonvolatile matter. Based on the following formula, the non-volatile content of the inorganic particle dispersion, the organic binder aqueous dispersion, or the composition dispersion for film formation was determined.
[Nonvolatile content in the dispersion (mass%)] = ([mass of the residue (g)] ÷ [mass of the dispersion (g)) × 100

<Average particle diameter in dispersion liquid of inorganic particle dispersion and composition dispersion for film formation>
The liquid obtained by diluting the inorganic particle dispersion or the composition dispersion for film formation with distilled water is measured with a particle size distribution analyzer (trade name: FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.) by a dynamic light scattering method, and cumulant The average particle size obtained by the legal analysis was taken as the average particle size in the dispersion liquid of the inorganic particle dispersion or the composition dispersion for film formation.

<Film thickness>
The thickness of the obtained sheet was measured using a Digimatic micrometer (manufactured by Mitutoyo). Ten arbitrary points were measured, and the average value was made into the film thickness.

<Density>
The density was calculated by measuring the mass and volume of a test piece cut out from the obtained sheet and dividing the mass by volume. The volume was calculated by measuring the length in the vertical direction and the length in the horizontal direction of the test piece using a caliper and measuring the film thickness based on the above-mentioned film thickness measuring method. Moreover, the mass of the test piece was measured using the precision balance with a four-digit decimal point about the test piece which measured the volume.

<Put strength test>
The puncture strength test was performed according to JIS Z 1707. Specifically, the pin puncture strength test is performed using the apparatus schematically shown in FIGS. 1 to 3, and after leaving the test piece 1 in a test environment of a temperature of 25 ° C. and a humidity of 50% for 1 hour, It is fixed on a substrate 5 provided with a circular opening, and the center of the test piece 1 is 50 mm ± 5 mm per minute for the tip 3n of a semicircular needle with a diameter of 1.0 mm and a tip shape radius of 0.5 mm. The test force F was used to puncture with a test force F, and the test force and the needle pushing distance (displacement) until the tip 3 n of the needle penetrated were measured. The measurement is performed on five test pieces, the average value of the test force and the needle insertion distance (displacement) is determined, and the average value of the obtained test force and the needle insertion distance (displacement) is used to perform elongation by the following method. The rate and stress were calculated.
-Growth rate-
The elongation rate is {(aperture radius)-(needle tip radius)} (a) shown in FIG. 2 and the maximum length (b) corresponding to a before the start of the test of the test piece by the test. Calculated by the following equation.
[Elongation rate (%)] = [(ba) (mm)] ÷ [a (mm)]

-Stress-
The stress at the peripheral portion 1 p was calculated by the following equation based on the following assumptions (1) and (2). In addition, the film thickness of a following formula used the value obtained by the said film thickness measurement method.
[Stress (MPa)]
= [[Test force F (N)] x [maximum length b (mm)]]
÷ {2π × [opening radius (mm)] × [film thickness (mm)] × [displacement h (mm)]}
Assumption (1): It is assumed that the sum of the vertical components σν of the stress σ is equal to the test force F of the needle tip 3n (F = Σσν).
The vertical component σν of the stress σ in the cross-sectional view of the apparatus shown in FIG. 3 indicates the vertical component σν at one point on the peripheral portion 1 p on the edge of the circular opening in the test piece 1 However, the sum of the vertical components σν of the stress σ obtained from the test force F means the sum of the vertical components σν in the entire cross section of the peripheral portion 1 p.
Assumption (2): It is assumed that the maximum length of the portion corresponding to a of the test piece before the start of the test is b shown in FIG. 2 (b = a before the start of the test).

<Tensile strength test>
Using a variable temperature tensile tester (trade name: Shimadzu Autograph AGS-100D, manufactured by Shimadzu Corporation), using a test piece with a width of 10 mm, the distance between chucks in the air at a temperature of 25 ° C and a humidity of 50% A tensile test was conducted under tension and a tensile test at a tensile speed of 10 mm / min under conditions of 80 mm and a tensile speed of 10 mm / min to determine the maximum stress and the elongation at break.

<Ion conductivity>
After leaving a cell formed with the following cell configuration for 30 minutes in a 25 ° C. constant temperature bath, AC impedance measurement is performed under the following measurement conditions, and the obtained intercept component (Ra) and the measurement sample are not inserted The ionic conductivity was calculated by the following equation using the intercept component (Rb) and the film thickness obtained by the above film thickness measurement method.
[Ion conductivity (mS / cm)] = [film thickness (cm)] ÷ [(Ra−Rb) × 1000 × 1.77]
・ Number of prepared cells: 5 cells (average value is stated)
Cell construction Working electrode: Ni plate counter electrode: Ni plate electrolyte solution: 6.7 mol / L potassium hydroxide aqueous solution sample saturated with zinc oxide Pretreatment: immersion in the above electrolyte overnight measurement effective area: 1.77 cm ²
-AC impedance measurement condition applied voltage: 10 mV vs. Open circuit voltage frequency domain: 100kHz to 100Hz

(Production example of inorganic particle dispersion)
Production Example 1
250 parts by mass of magnesium hydroxide (trade name: 200-06 H, manufactured by Kyowa Chemical Industry Co., Ltd., average particle diameter: 690 nm), dispersant (trade name: AQUALIC DL40S, manufactured by Nippon Shokubai Co., Ltd., nonvolatile content: 44%) Parts and 110 parts by mass of ion-exchanged water were weighed, and after kneading for 1 hour using a sand mill, filtration was performed to obtain an inorganic particle dispersion liquid having magnesium hydroxide as inorganic particles. The nonvolatile matter content of the obtained inorganic particle dispersion was 69.3%, and the average particle diameter in the dispersion of the inorganic particle dispersion was 550 nm.

Production Example 2
250 parts by mass of hydrotalcite (trade name: DHT-6, manufactured by Kyowa Chemical Industry Co., Ltd., average particle diameter: 360 nm), dispersant (trade name: AQUALIC DL40S, manufactured by Nippon Shokubai Co., Ltd., nonvolatile content: 44%) 5 parts Parts and 100 parts by mass of ion-exchanged water were measured, and after kneading for 1 hour using a sand mill, filtration was performed to obtain an inorganic particle dispersion having hydrotalcite as inorganic particles. The nonvolatile content of the obtained inorganic particle dispersion was 70.1%, and the average particle size in the dispersion of the inorganic particle dispersion was 320 nm.

[Production Example 3]
250 parts by mass of magnesium hydroxide (trade name: 10A, manufactured by Kamijima Chemical Industry Co., Ltd., average particle diameter: 3.3 μm), dispersant (trade name: Aqualic DL40S, manufactured by Nippon Shokubai Co., Ltd., nonvolatile content: 44%) Part, 125 parts by mass of ion exchange water and zirconia beads were weighed, and after kneading for 2 hours using a ball mill, filtration was performed to obtain an inorganic particle dispersion liquid having magnesium hydroxide as inorganic particles. The non-volatile content of the obtained inorganic particle dispersion was 65.4%, and the average particle size in the dispersion of the inorganic particle dispersion was 640 nm.

Example 1
50 parts by mass of the inorganic particle dispersion obtained in Production Example 1, 30 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-116, manufactured by Nippon A & L Co., nonvolatile content: 50.5%) And 2.6 mass parts of zirconium ammonium carbonate aqueous solution (43 mass%) were measured, and after mixing, filtration and vacuum degassing were performed, and the composition for film-forming was obtained. The nonvolatile matter of the obtained composition for film formation was 60.1%, and the average particle size was 242 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet had a film thickness of 83 μm, a density of 1.48 g / cm ³ , an ion conductivity of 8.0 mS / cm, an elongation in a pin puncture strength test of 4.2%, a stress of 2.6 MPa and a tensile strength test The maximum stress in this case was 5.3 MPa and the elongation at break was 24%.

Example 2
50 parts by mass of the inorganic particle dispersion obtained in Production Example 2 and 15 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-116, manufactured by Nippon A & L Co., nonvolatile content: 50.5%) After measuring and mixing 1.8 mass parts of zirconium ammonium carbonate aqueous solution (43 mass%) and 2.5 mass parts of ion exchange water, filtration and vacuum degassing were performed to obtain a composition for film formation. The non-volatile content of the obtained composition for film formation was 61.8%, and the average particle size was 189 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a film thickness of 92 μm, a density of 1.28 g / cm ³ , an ion conductivity of 77 mS / cm, an elongation in a pin puncture strength test of 2.8%, a stress of 1.3 MPa and a maximum in tensile strength test The stress was 6.4 MPa and the breaking elongation was 14%.

[Example 3]
50 parts by mass of the inorganic particle dispersion obtained in Production Example 1, 21 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-152, manufactured by Nippon A & L Co., nonvolatile content: 48%), and carbonic acid After measuring and mixing 1.8 mass parts of zirconium ammonium aqueous solution (43 mass%), filtration and vacuum degassing were performed to obtain a composition for film formation. The nonvolatile matter of the obtained composition for film formation was 61.5%, and the average particle diameter was 277 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a film thickness of 115 μm, a density of 1.24 g / cm ³ , an ion conductivity of 29 mS / cm, an elongation in a puncture strength test of 7.8%, a stress of 1.4 MPa, and a maximum in tensile strength test The stress was 5.1 MPa and the breaking elongation was 12%.

Example 4
50 parts by mass of the inorganic particle dispersion obtained in Production Example 1, 31 parts by mass of an aqueous solution (nonvolatile content: 15%) of polyvinyl alcohol (trade name: GOOSENOL (registered trademark) NL-05, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) After 2 parts by mass of an aqueous solution of ammonium zirconium carbonate (43% by mass) and 5 parts by mass of ion exchange water were weighed and mixed, filtration and vacuum degassing were performed to obtain a composition for film formation. The nonvolatile matter of the obtained composition for film formation was 44.7%, and the average particle size was 478 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet had a film thickness of 98 μm, a density of 1.18 g / cm ³ , an ionic conductivity of 73 mS / cm, an elongation in a pin puncture strength test of 3.3%, a stress of 1.8 MPa and a maximum in tensile strength test The stress was 6.5 MPa and the breaking elongation was 10%.

[Example 5]
50 parts by mass of the inorganic particle dispersion obtained in Production Example 2 and 15 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-116, manufactured by Nippon A & L Co., nonvolatile content: 50.5%) After 1 part by mass of a zirconium ammonium carbonate aqueous solution (43% by mass) and 5 parts by mass of ion-exchanged water were weighed and mixed, filtration and vacuum degassing were performed to obtain a composition for film formation. The non-volatile content of the obtained composition for film formation was 60.7%, and the average particle size was 195 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet had a film thickness of 96 μm, a density of 1.31 g / cm ³ , an ion conductivity of 58 mS / cm, an elongation in a pin puncture strength test of 2.4%, a stress of 1.4 MPa and a maximum in tensile strength test The stress was 6.3 MPa and the breaking elongation was 10%.

[Example 6]
50 parts by mass of the inorganic particle dispersion obtained in Production Example 2 and 15 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-116, manufactured by Nippon A & L Co., nonvolatile content: 50.5%) Then, 8.5 parts by mass of an aqueous solution of ammonium zirconium carbonate (43% by mass) was weighed and mixed, followed by filtration and vacuum degassing to obtain a composition for film formation. The non-volatile content of the obtained composition for film formation was 60.3%, and the average particle diameter was 192 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a film thickness of 92 μm, a density of 1.22 g / cm ³ , an ion conductivity of 82 mS / cm, an elongation in a puncture strength test of 3.5%, a stress of 1.7 MPa, and a maximum in tensile strength test The stress was 6.2 MPa and the breaking elongation was 16%.

[Example 7]
50 parts by mass of the inorganic particle dispersion obtained in Production Example 2 and 15 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-116, manufactured by Nippon A & L Co., nonvolatile content: 50.5%) And 12 mass parts of zirconium ammonium carbonate aqueous solution (43 mass%) were measured, and after mixing, filtration and vacuum degassing were performed, and the composition for film-forming was obtained. The nonvolatile matter of the obtained composition for film formation was 57.9%, and the average particle size was 201 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a thickness of 101 μm, a density of 1.20 g / cm ³ , an ionic conductivity of 84 mS / cm, an elongation in a puncture strength test of 3.8%, a stress of 1.8 MPa and a maximum in tensile strength test The stress was 6.8 MPa and the breaking elongation was 19%.

[Example 8]
50 parts by mass of the inorganic particle dispersion obtained in Production Example 2 and 15 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-116, manufactured by Nippon A & L Co., nonvolatile content: 50.5%) And 18 parts by mass of an aqueous solution of zirconium oxychloride (30% by mass, solubility of zirconium oxychloride in methanol: 46.6 g / 100 mL), and after mixing, filtration and vacuum degassing are carried out to obtain a film forming composition Obtained. The nonvolatile content of the obtained composition for film formation was 55.0%, and the average particle size was 213 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a film thickness of 89 μm, a density of 1.21 g / cm ³ , an ion conductivity of 85 mS / cm, an elongation in a puncture strength test of 3.7%, a stress of 1.6 MPa and a maximum in tensile strength test The stress was 6.7 MPa and the breaking elongation was 17%.

[Example 9]
50 parts by mass of the inorganic particle dispersion obtained in Production Example 2 and 15 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-116, manufactured by Nippon A & L Co., nonvolatile content: 50.5%) After measuring and mixing 0.7 mass part of zirconium ammonium carbonate aqueous solution (43 mass%) and 5 mass parts of ion-exchanged water, filtration and vacuum degassing were performed to obtain a composition for film formation. The nonvolatile matter of the obtained composition for film formation was 59.8%, and the average particle size was 190 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a film thickness of 96 μm, a density of 1.34 g / cm ³ , an ion conductivity of 48 mS / cm, an elongation in a pin puncture strength test of 2.0%, a stress of 1.5 MPa and a maximum in tensile strength test The stress was 6.1 MPa and the breaking elongation was 9.2%.

[Example 10]
50 parts by mass of the inorganic particle dispersion obtained in Production Example 3, 10 parts by mass of a carboxy-modified polyolefin aqueous dispersion (trade name: Chemipal S100, Mitsui Chemicals, Inc., nonvolatile content: 27%), aqueous solution of zirconium ammonium carbonate (43 parts) %) 3 parts by mass and 6.5 parts by mass of ion-exchanged water were weighed and mixed, followed by filtration and vacuum degassing to obtain a composition for film formation. The nonvolatile matter of the obtained composition for film formation was 55.0%, and the average particle size was 380 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a film thickness of 105 μm, a density of 1.15 g / cm ³ , an ion conductivity of 32 mS / cm, an elongation in a puncture strength test of 2.3%, a stress of 2.1 MPa and a maximum in tensile strength test The stress was 7.0 MPa and the breaking elongation was 13%.

[Example 11]
50 parts by mass of the inorganic particle dispersion obtained in Production Example 1, 10 parts by mass of a carboxy-modified polyolefin aqueous dispersion (trade name: Arrow Base DA-1010, Mitsui Chemicals, Inc., nonvolatile content: 25%), aqueous solution of zirconium ammonium carbonate After measuring and mixing 3 mass parts of (43 mass%) and 5.2 mass parts of ion exchange water, filtration and vacuum degassing were performed, and the composition for film-forming was obtained. The nonvolatile component of the obtained composition for film formation was 55.1%, and the average particle size was 320 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a film thickness of 92 μm, a density of 1.12 g / cm ³ , an ion conductivity of 36 mS / cm, an elongation in a puncture strength test of 3.8%, a stress of 1.8 MPa and a maximum in tensile strength test The stress was 6.1 MPa and the breaking elongation was 17%.

[Example 12]
50 parts by mass of the inorganic particle dispersion obtained in Production Example 3, 21 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-152, manufactured by Nippon A & L Co., nonvolatile content: 48%) and titanium After measuring and mixing 2.2 mass parts of dihydroxy dilactate ammonium aqueous solution (41 mass%), filtration and vacuum degassing were performed, and the composition for film-forming was obtained. The nonvolatile matter of the obtained composition for film formation was 61.8%, and the average particle size was 284 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a film thickness of 89 μm, a density of 1.27 g / cm ³ , an ion conductivity of 24 mS / cm, an elongation in a puncture strength test of 7.1%, a stress of 1.8 MPa and a maximum in tensile strength test The stress was 5.5 MPa and the breaking elongation was 14%.

[Example 13]
The composition for film formation obtained in Example 3 is coated on a non-woven fabric (trade name: Papiron BFN No. 2, manufactured by Three Crystals, thickness: 92 μm) with a comma coater, dried, and used for film formation. The sheet (separator) which consists of a composition and a nonwoven fabric was obtained.
The obtained sheet has a film thickness of 115 μm, a density of 1.08 g / cm ³ , an ion conductivity of 25 mS / cm, an elongation in a puncture strength test of 7.7%, a stress of 4.2 MPa and a maximum in tensile strength test The stress was 12 MPa and the breaking elongation was 11%.

Comparative Example 1
50 parts by mass of the inorganic particle dispersion obtained in Production Example 1, 30 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-116, manufactured by Nippon A & L Co., nonvolatile content: 50.5%) And after 2.8 mass parts of ion-exchange water were measured and mixed, filtration and vacuum degassing were performed, and the composition for film-forming was obtained. The non-volatile content of the obtained composition for film formation was 59.8%, and the average particle size was 193 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a film thickness of 85 μm, a density of 1.58 g / cm ³ , an ion conductivity of 4.9 mS / cm, an elongation in a puncture strength test of 1.7%, a stress of 2.4 MPa, and a tensile strength test The maximum stress in was 5.5 MPa and the elongation at break was 6.3%.

Comparative Example 2
50 parts by mass of the inorganic particle dispersion obtained in Production Example 2 and 15 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-116, manufactured by Nippon A & L Co., nonvolatile content: 50.5%) And after measuring and mixing 3.7 mass parts of ion exchange waters, filtration and vacuum degassing were performed and the composition for film-forming was obtained. The nonvolatile matter of the obtained composition for film formation was 61.9%, and the average particle diameter was 192 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet had a thickness of 87 μm, a density of 1.36 g / cm ³ , an ionic conductivity of 40 mS / cm, an elongation in a puncture strength test of 1.0%, a stress of 1.5 MPa, and a maximum in tensile strength test The stress was 6.5 MPa and the breaking elongation was 4.2%.

Comparative Example 3
50 parts by mass of the inorganic particle dispersion obtained in Production Example 1, 21 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (trade name: NALSTAR SR-152, manufactured by Nippon A & L Co., nonvolatile content: 48%), water 0.5 parts by mass of zirconium oxide (solubility in water: 0.02 g / 100 mL) and 3.5 parts by mass of ion-exchanged water are weighed and mixed, followed by filtration and vacuum degassing to obtain a composition for film formation. The The nonvolatile matter of the obtained composition for film formation was 60.0%, and the average particle size was 291 nm.
The film-forming composition obtained was coated on a silicone-treated side of a polyethylene terephthalate (PET) film (release film) whose one side was silicone-treated and dried by a comma coater. Was peeled from the release film to obtain a composition sheet for film formation.
The obtained sheet has a thickness of 90 μm, a density of 1.48 g / cm ³ , an ionic conductivity of 16 mS / cm, an elongation in a puncture strength test of 1.2%, a stress of 2.9 MPa and a maximum in tensile strength test The stress was 6.3 MPa and the breaking elongation was 3.6%.

As described above, in the film-forming composition to which the polyvalent metal compound having a predetermined solubility is added, the stress is improved in each strength test while the ion conductivity is improved as compared with the case where the polyvalent metal compound is not added. The sheet | seat which was excellent in the comprehensive strength which elongation rate improved was maintained, being maintained.

Specifically, when the types of the inorganic particles and the organic binder are the same, and the content ratio of these is the same as in Example 1 and Comparative Example 1, the polyvalent metal compound is added in Example 1. As a result, the ion conductivity is 8.0 mS / cm, which is superior to the ion conductivity (4.9 mS / cm) of Comparative Example 1. Moreover, in Example 1, the stress of 2.6 MPa in the puncture strength test and the maximum stress of 5.3 MPa in the tensile strength test are sufficiently maintained (in Comparative Example 1, the stress of 2.4 MPa in the puncture strength test, tension) Along with the maximum stress of 5.5 MPa in the strength test, the elongation in the puncture strength test is 4.2%, the elongation at break in the tensile strength test is 24%, and the elongation in the comparative example 1 (the elongation in the puncture strength test is 1.7%) And the elongation at break in the tensile strength test is 6.3% and superior, and is superior to Comparative Example 1 in overall strength.

Further, when the types of the inorganic particles and the organic binder are the same and the content ratio of these is the same as in Examples 5 and 9 and Comparative Example 2, the polyvalent metal compound is added in Examples 5 and 9. As a result, the ion conductivity is 58 mS / cm, 48 mS / cm, which is superior to the ion conductivity (40 mS / cm) of Comparative Example 2. In Examples 5 and 9, the stress in the puncture strength test is 1.4 MPa and 1.5 MPa, respectively, and the maximum stress in the tensile strength test is 6.3 MPa and 6.1 MPa, respectively, and the stress is sufficiently maintained (comparison In Example 2, together with the stress of 1.5 MPa in the puncture strength test and the maximum stress of 6.5 MPa in the tensile strength test, the elongation in the puncture strength test is 2.4% and 2.0%, respectively, and the elongation at break in the tensile strength test Are 10% and 9.2% respectively, which are superior to the elongation of Comparative Example 2 (elongation 1.0% in puncture strength test, elongation at break 4.2% in tensile strength test), and overall strength Is superior to Comparative Example 2 in

The sheet of such an embodiment is compatible with ion conductivity and strength in a well-balanced manner as a separator used for electrochemical devices such as batteries, capacitors, capacitors, sensors, and electrolytic devices.

1: Test piece 1 p: Peripheral portion of test piece 3: Needle 3 n: Needle tip 5: Substrate a: {(opening radius)-(needle tip radius)}
b: Maximum length of the part corresponding to a before the start of test of the test piece by test h: Needle pushing distance (displacement)
F: Test force (spun strength)
σ: Edge stress σv: Stress perpendicular component

Claims (5)

A composition for a separator for an electrochemical device, comprising: inorganic particles; and an organic binder having at least one functional group selected from the group consisting of a carboxy group, a carboxylate group which is a salt thereof, and a hydroxyl group.
The composition for a separator for an electrochemical device, further comprising a polyvalent metal compound in which at least one of the solubility in water and the solubility in methanol is 3 g / 100 mL or more. The composition for a separator for an electrochemical element according to claim 1, wherein the polyvalent metal compound has an oxygen atom and / or an atomic group having an oxygen atom, and the oxygen atom is bonded to a metal. object. The composition for a separator for an electrochemical device according to claim 1 or 2, wherein the content of the polyvalent metal compound is 0.2 to 15% by mass in 100% by mass of the composition. . An electrochemical element separator comprising the composition for an electrochemical element separator according to any one of claims 1 to 3. An electrochemical device comprising the separator for an electrochemical device according to claim 4.

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