JP7100514B2 - Inorganic-organic composite membrane and diaphragm for electrochemical devices - Google Patents

Description

The present invention relates to an inorganic-organic composite membrane and a diaphragm for an electrochemical device. More specifically, the present invention relates to an inorganic-organic composite film having high film strength and excellent flexibility, and a diaphragm for an electrochemical device.

Various applications of the laminated film composed of an organic layer and a support have been studied, and a laminated film having excellent properties required for each application has been developed so far. As one of the uses of such a laminated film, a diaphragm for electrolytic water electrolysis, a diaphragm for an electrochemical element such as a battery separator is known.

For example, the alkaline water electrolysis diaphragm is a membrane used for electrolysis of water, which is one of the industrial methods for producing hydrogen, and is used to separate an anode chamber and a cathode chamber in an electrolytic cell.
The electrolysis of water is carried out by the movement of electrons (or ions). Therefore, in order to efficiently perform electrolysis, the diaphragm for alkaline water electrolysis is required to have high ion permeability. Further, a gas barrier property capable of blocking oxygen generated in the anode chamber and hydrogen generated in the cathode chamber is required. Further, since the electrolysis of water is carried out at 80 to 90 ° C. using alkaline water having a high concentration of about 30%, high temperature resistance and alkali resistance are also required.

Further, the battery separator is a film used for the purpose of insulating the positive electrode and the negative electrode in a battery such as a zinc secondary battery, and separates the positive electrode and the negative electrode, holds an electrolytic solution, and forms ions between the positive electrode and the negative electrode. Used to ensure conductivity. The battery separator is required to have excellent ionic conductivity. Further, in the battery separator, dendrites grow as the battery is charged and discharged, which may cause a short circuit. Therefore, it is desired that the battery separator can suppress the generation of dendrites and prevent short circuits.

Various such diaphragms have been known so far.
For example, Patent Document 1 includes an ion permeable film and a porous reinforcing body arranged on one side or both sides of the ion permeable film, and the ion permeable film is a medium-acidic ion-exchange group or a weakly acidic ion-exchange group. , The porous reinforcing body is composed of a polymer having a strongly basic ion exchange group, a medium basic ion exchange group or a weakly basic ion exchange group, and the porous reinforcing body is wettable with respect to a potassium hydroxide aqueous solution having a concentration of 30% by weight. A diaphragm for alkaline water electrolysis showing the above is described.
Further, for example, Patent Document 2 describes a substrate for an alkaline water electrolyzed nonwoven fabric composed of a thermoplastic fiber having an average single fiber fineness of 0.1 to 10 dtex and a number of crimps of 2 to 10 threads / 25 mm. , A base material for an alkaline water electrolysis fiber including a non-woven fabric as the base material is described.

Japanese Unexamined Patent Publication No. 2013-249509 Japanese Unexamined Patent Publication No. 2016-89197

However, such a conventional laminated film is expected to be in contact with electrodes and to be subjected to various stresses when it is constructed in an electrochemical cell stack or in actual operation, and extremely high film strength is required. However, the request has not been fully met yet. It is also desired that the laminated film has high flexibility so that it can be applied to various usage modes. In particular, when such a laminated film is applied to an electrochemical element such as a diaphragm for alkaline water electrolysis or a battery separator, it has been desired to realize a higher film strength and excellent flexibility than before. ..

The present invention has been made in view of the above situation, and an object of the present invention is to provide an inorganic-organic composite film having high film strength and excellent flexibility.

The present inventors have made various studies on an organic layer containing a polymer and a film having a support. As a result, the organic layer contains inorganic compound particles in addition to the polymer, and the support has an average fiber diameter of 3 to 20 μm. It was found that by using a certain non-woven fabric, the organic layer and the support can be composited, the strength of the film can be significantly improved, and an inorganic organic composite film having excellent flexibility can be obtained. The present invention has been completed.

That is, the present invention is a film containing an organic layer containing an organic polymer and a support, wherein the organic layer further contains inorganic compound particles, and the support is a non-woven fabric having an average fiber diameter of 3 to 20 μm. It is an inorganic-organic composite film characterized by being.

The present invention is also a film containing an organic layer containing an organic polymer and a support, wherein the organic layer further contains inorganic compound particles, and the support is a non-woven fabric having an average fiber diameter of 3 to 20 μm. It is a diaphragm for an electrochemical element, which is characterized by being.

The nonwoven fabric preferably has a basis weight of 20 to 150 g / m ² .

The nonwoven fabric preferably contains at least one selected from the group consisting of an aliphatic hydrocarbon polymer and polyphenylene sulfide.

The inorganic compound particles are preferably at least one selected from the group consisting of metal oxides, metal hydroxides, and layered double hydroxides.

The organic polymer is preferably at least one selected from the group consisting of an aliphatic hydrocarbon group-containing polymer, an aromatic hydrocarbon group-containing polymer, and a conjugated diene-based polymer.

The aromatic hydrocarbon group-containing polymer is preferably at least one selected from the group consisting of polysulfone, polyethersulfone, and polyphenylsulfone.

The conjugated diene polymer may be at least one selected from the group consisting of a styrene-butadiene copolymer, a polybutadiene, a polyisoprene, an acrylonitrile-butadiene copolymer, and an isobutylene-isoprene copolymer. preferable.

According to the present invention, it is possible to provide an inorganic-organic composite film having high film strength and excellent flexibility. The inorganic-organic composite membrane of the present invention can be preferably used as a diaphragm for an electrochemical element, and more preferably can be used as a diaphragm for alkaline water electrolysis or a battery separator.

The present invention will be described in detail below.
It should be noted that a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

1. 1. Inorganic-Organic Composite Film The inorganic-organic composite film of the present invention contains an organic layer containing an organic polymer and a support, the organic layer further contains inorganic compound particles, and the support has an average fiber diameter of 3 to 3 to. It is characterized by being a non-woven fabric having a size of 20 μm.
Since the inorganic-organic composite film of the present invention has the above-mentioned structure, it has excellent film strength and is also excellent in flexibility.

The inorganic-organic composite film of the present invention has high film strength and excellent flexibility because the organic layer contains inorganic compound particles and a non-woven fabric having an average fiber diameter in a specific range is used as a support. It is presumed that, in addition to the entanglement between the fibers, the material for forming the organic layer covers the fiber surface, so that the organic layer and the support can be suitably laminated or integrated.

In the present invention, a non-woven fabric having an average fiber diameter of 3 to 20 μm is used as the support. When a non-woven fabric having an average fiber diameter within the above range is used, the organic layer forming material easily impregnates the non-woven fabric when forming the inorganic-organic composite film of the present invention, and the organic layer and the support are integrated. A composite membrane can be prepared and the membrane strength can be increased. In addition, the obtained composite film is also excellent in flexibility.
When the average fiber diameter is less than 3 μm, the organic layer forming material cannot sufficiently invade the support, and as a result, the organic layer cannot be sufficiently formed, and an inorganic organic composite film having excellent film strength is obtained. It may not be possible to form. If the average fiber diameter exceeds 20 μm, the flexibility of the inorganic-organic composite film may decrease.

The average fiber diameter of the nonwoven fabric is preferably 4 μm or more, more preferably 5 μm or more, preferably 15 μm or less, and more preferably 10 μm or less in terms of improving the film strength.
The average fiber diameter was determined by observing the surface of the non-woven fabric at a magnification of 50 with a laser microscope, measuring the fiber diameter of each of the 30 fibers observed in the obtained image (laser microscope image), and measuring the fiber diameter of each fiber. It can be obtained by averaging the fiber diameters (simple average). As the fiber diameter of each fiber, a measured value at any one place may be adopted as long as the fiber diameter is uniform, but it is preferable to use the average value of the measured values at any three places as the fiber diameter of each fiber. .. The fiber diameter means a length that is the shortest distance in the thickness direction of the fiber. In addition, in measuring the fiber diameter of each fiber, analysis software (Image-Pro Premier) can also be used.
The average fiber diameter referred to in the present invention is typically a value obtained by the above-mentioned measuring method, in other words, the diameter (length in the thickness direction) of the fibers constituting the non-woven fabric in the laser microscope image of the non-woven fabric. Is the average value of.

The inorganic-organic composite membrane of the present invention will be described below.
The inorganic-organic composite film of the present invention includes an organic layer and a support.
<Organic layer>
The organic layer contains an organic polymer and further contains inorganic compound particles. When the organic layer contains inorganic compound particles in addition to the organic polymer and is combined with a support described later, the film has high strength and excellent flexibility.

(Organic polymer)
Examples of the organic polymer contained in the organic layer include an aliphatic hydrocarbon group-containing polymer such as polyethylene; an aromatic hydrocarbon group-containing polymer such as polystyrene; an ether group-containing polymer such as alkylene glycol; and a hydroxyl group-containing polymer such as polyvinyl alcohol. Polymers; amide group-containing polymers such as polyacrylamide; imide group-containing polymers such as polymaleimide; (meth) acrylic polymers; halogen atom-containing polymers such as polyvinylidene fluoride and polytetrafluoroethylene; ammonium salt-containing polymers; phosphonium salt-containing Polymers; ion-exchangeable polymers; natural rubbers; conjugated diene polymers; saccharides such as hydroxyalkyl cellulose (eg, hydroxyethyl cellulose); polymers such as amino group-containing polymers such as polyethyleneimine. These polymers may be used alone or in combination of two or more.

The organic polymer not only acts as a binder polymer for inorganic compound particles, but also acts as a matrix component for controlling film strength and flexibility by combining with a support to control the structure of the composite film. preferable. From this point of view, the organic polymer is at least one selected from the group consisting of an aliphatic hydrocarbon group-containing polymer, an aromatic hydrocarbon group-containing polymer, and a conjugated diene-based polymer. preferable.

Examples of the aliphatic hydrocarbon group-containing polymer include polymers having a monomer unit derived from an aliphatic hydrocarbon group-containing monomer.
Examples of the aliphatic hydrocarbon group-containing monomer include a chain-like or branched monomer containing a saturated or unsaturated hydrocarbon group, and preferably a monomer containing a chain-shaped or branched saturated hydrocarbon group. ..
Examples of the aliphatic hydrocarbon group-containing monomer include olefins such as ethylene, propylene, butene, 1-hexene, 1-heptene, and 1-octene.
The aliphatic hydrocarbon group-containing polymer may be a homopolymer composed of one kind of the aliphatic hydrocarbon group-containing monomer, or may be a copolymer composed of two or more kinds.
As the aliphatic hydrocarbon group-containing polymer, polyolefin-based polymers such as polyethylene, polypropylene, polybutene, and polymethylpentene are preferable, and polyethylene and polyproprene are more preferable.

Examples of the aromatic hydrocarbon group-containing polymer include those having a monomer unit having an aromatic hydrocarbon group such as benzene. Specific examples thereof include polyethylene terephthalate, polybutylene terephthalate, polybutylene naphthalate, and polystyrene. , Polysulfone, polyethersulfone, polyphenylene sulfide, polyphenylsulfone, polyarylate, polyetherimide, polyimide, polyamideimide and the like. Among them, at least one selected from the group consisting of polysulfone, polyethersulfone, and polyphenylsulfone is preferable, and polysulfone is more preferable, because the membrane strength can be further increased.

The conjugated diene-based polymer is not particularly limited as long as it has a monomer unit derived from the conjugated diene-based monomer, but it is preferably one having a monomer unit derived from an aromatic vinyl monomer.

The conjugated diene-based monomer is preferably an aliphatic conjugated diene-based monomer. Examples of the aliphatic conjugated diene-based monomer include 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene, chloroprene and the like, and 1,3-butadiene is preferable. The conjugated diene-based monomer may be used alone or in combination of two or more.

The conjugated diene polymer may be a homopolymer such as polybutadiene or polyisoprene, or may be a copolymer, but a copolymer is preferable, and the aromatic vinyl monomer is particularly derived. It is more preferable that the copolymer further has the above-mentioned monomer unit.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene and o-methoxy. Styrene, m-methoxystyrene, p-methoxystyrene, o-ethoxystyrene, m-ethoxystyrene, p-ethoxystyrene, o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, o-chlorostyrene, m-chloro Styrene, p-chlorostyrene, o-bromostyrene, m-bromostyrene, p-bromostyrene, o-acetoxystyrene, m-acetoxystyrene, p-acetoxystyrene, o-tert-butoxystyrene, m-tert-butoxystyrene , P-tert-butoxystyrene, o-tert-butylstyrene, m-tert-butylstyrene, p-tert-butylstyrene, vinyltoluene and the like. Among these, styrene and α-methylstyrene are preferable. These aromatic vinyl monomers may be used alone or in combination of two or more.

In the conjugated diene polymer, the mass ratio of the monomer unit derived from the aliphatic conjugated diene monomer to the monomer unit derived from the aromatic vinyl monomer is preferably 1/9 or more, and preferably 2/8 or more. Is more preferable, and 3/7 or more is further preferable. The mass ratio is preferably 9/1 or less, more preferably 8/2 or less, and even more preferably 7/3 or less.

The conjugated diene polymer is a styrene-butadiene copolymer, polybutadiene, polyisoprene, or acrylonitrile-butadiene copolymer in that the film strength and flexibility of the inorganic-organic composite film can be further improved. , Or an isobutylene-isoprene-based copolymer is preferable. These may be used alone or in combination of two or more.

The conjugated diene-based polymer may have a monomer unit derived from other unsaturated monomers other than the monomer unit derived from the aliphatic conjugated diene-based monomer and the monomer unit derived from the aromatic vinyl monomer.

Examples of other unsaturated monomers include acid group-containing vinyl monomers such as itaconic acid, acrylic acid, methacrylic acid, fumaric acid, maleic acid, acrylamide methylpropane sulfonic acid, and styrene sulfonate; methyl (meth) acrylic acid, and the like. Ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, (meth) acrylic (Meta) acrylic acid ester monomers such as hexyl acid, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate; 2-Hydroxyethyl acrylate, 4-hydroxybutyl (meth) acrylate and other hydroxyl group-containing vinyl monomers, nitrile group-containing vinyl monomers such as (meth) acrylonitrile, (meth) acrylamide, N-methylol (meth) acrylamide, (Meta) acrylamide-based monomers such as N-ethylol (meth) acrylamide, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, divinylbenzene, ethylene glycol dimethacrylate, isopropylene glycol diacrylate, tetramethylene glycol dimethacrylate and the like. Functional vinyl monomers; examples thereof include alkossisilane group-containing vinyl monomers such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropyltriethoxysilane. These may be used alone or in combination of two or more.

The mass ratio of the monomer unit derived from other unsaturated monomers in 100% by mass of the conjugated diene polymer is preferably 40% by mass or less, more preferably 20% by mass or less, and 10% by mass or less. It is more preferably present, and particularly preferably 5% by mass or less.

The organic polymer can be produced, for example, by polymerizing a monomer component forming a structural unit contained in the above-mentioned organic polymer. The polymerization may be appropriately selected from known methods.

The content of the organic polymer is preferably 1% by mass or more, more preferably 5% by mass or more, and preferably 7% by mass or more with respect to 100% by mass of the inorganic organic composite film of the present invention. More preferred. The content of the organic polymer is preferably 70% by mass or less, more preferably 35% by mass or less, and 30% by mass or less with respect to 100% by mass of the inorganic organic composite film of the present invention. Is even more preferable.

(Inorganic compound particles)
Examples of the inorganic compound particles include particles made of a compound having at least one element selected from Group 1 to Group 17 of the periodic table.
At least one element selected from Group 1 to Group 17 of the periodic table includes alkali metals, alkaline earth metals, Sc, Y, lanthanoids, Ti, Zr, Hf, V, Nb, Ta, Cr and Mo. , W, Mn, Fe, Ru, Co, Ni, Pd, Cu, Au, Zn, Cd, B, Al, Ga, In, Tl, C, Si, Ge, Sn, Pb, N, P, Sb, Bi , S, Se, Te, F, Cl, and Br, preferably at least one element selected from the group. Among them, at least one element selected from Group 1 to Group 15 of the periodic table is preferable, and Li, Na, K, Cs, Mg, Ca, Ba, Sc, Y, lanthanoid, Ti, Zr, Nb, Cr, From Mn, Fe, Ru, Co, Ni, Pd, Cu, Au, Zn, Cd, B, Al, Ga, In, Tl, C, Si, Ge, Sn, Pb, N, P, Sb, and Bi At least one element selected from the group is more preferred. More preferably, Li, Mg, Ca, Ba, Sc, Y, lanthanoids, Ti, Zr, Nb, Cr, Mn, Fe, Ru, Co, Ni, Pd, Cu, Zn, Cd, B, Al, Ga, It is at least one element selected from the group consisting of In and Tl.

Examples of the compound having at least one element selected from Group 1 to Group 17 of the above periodic table include oxides; composite oxides; layered compound hydroxides; hydroxides; clay compounds; solid solutions; Alloys; zeolites; halides; carboxylate compounds; carbonate compounds; hydrogen carbonate compounds; nitrate compounds; sulfuric acid compounds; sulfonic acid compounds; phosphoric acid compounds such as hydroxyapatite; subphosphoric compounds; hypophobic acid compounds, boric acid compounds; Examples thereof include silicic acid compounds; aluminic acid compounds; sulfides; onium compounds; salts and the like. Preferably, an oxide; a composite oxide; a layered double hydroxide such as hydrotalcite; a hydroxide; a clay compound; a solid solution; a zeolite; a fluoride; a phosphoric acid compound; a boric acid compound; a silicic acid compound; an aluminic acid compound. ; Salt is mentioned.

Among these, oxides and hydroxides are examples of compounds having at least one element selected from Group 1 to Group 17 of the periodic table in that the film strength and flexibility can be further enhanced. , At least one compound selected from the group consisting of a layered compound hydroxide and a phosphoric acid compound, and preferably selected from the group consisting of an oxide, a hydroxide, and a layered compound hydroxide. It is more preferably at least one compound, and even more preferably at least one compound selected from the group consisting of metal oxides, metal hydroxides, and layered compound hydroxides.

Examples of the oxide include metal oxides such as cerium oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, zirconium oxide, titanium oxide, aluminum oxide, iron oxide, zinc oxide, tin oxide and bismuth oxide. Calcium oxide and zinc oxide are preferable, and cerium oxide is more preferable. Further, the cerium oxide may be a solid solution with a metal oxide such as samarium oxide, gadolinium oxide, bismuth oxide or zirconium oxide. Further, it may have an oxygen defect.

Examples of the hydroxide include cerium hydroxide, zirconium hydride, barium hydroxide, strontium hydroxide, calcium hydroxide, magnesium hydroxide, titanium hydroxide and the like.

The oxides and hydroxides may be natural products or synthetic products. Further, the surface may be untreated, or may be surface-treated with a silane coupling agent, stearic acid, oleic acid, phosphoric acid ester or the like.

The layered double hydroxide has the following general formula;
[M ¹ _1-x M ² _x (OH) ₂ ] (An-) _{x / n} ^· mH ₂ O
(M ¹ represents a divalent metal ion which is any one of Mg, Fe, Zn, Ca, Li, Ni, Co, Cu and Mn. M ² represents Al, Fe, Mn, Co, Cr and In. Represents a trivalent metal ion that is one of them. An-represents a monovalent or more and _trivalent or less anion such as OH-, ^{Cl- , NO3-} _, ^CO3-2- , ^{COO- ,} etc. m is 0. The above number. N is a number of 1 to 3. x is a number of 0.20 to 0.40). It is preferable that An − represents a ^divalent or less anion.

The layered double hydroxides are naturally produced (for example, hydrotalcite, Manasseite, Motucolaite, Stichtite, Sjogrenite, Barbertite). Auroraite, Iomaite, Chlormagalminite, Hydrocalmite, GreenRust 1, Berthierine, Tacobite, Tacobite Reevesite), Honesite, Eardlyite, Mixnerite, etc.), or artificially synthesized ones, at 150 ° C or higher and 900 ° C or lower. It may be a compound dehydrated by firing, a compound obtained by decomposing anions in layers, or a compound in which anions in layers are exchanged for hydroxide ions or the like.

As the layered double hydroxide, Mg—Al-based layered double hydroxide is preferable, and hydrotalcite is more preferable. A compound having a functional group such as a hydroxyl group, an amino group, a carboxyl group, or a silanol group may be coordinated with the hydrotalsite.

As the phosphoric acid compound, for example, hydroxyapatite is preferable.
The hydroxyapatite is a compound typified by Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ , and is a compound in which the amount of Ca is reduced depending on the conditions at the time of preparation, a hydroxyapatite compound in which an element other than Ca is introduced, and the like. May be used as the above-mentioned inorganic compound particles.

Among the above-mentioned inorganic compound particles, at least one selected from the group consisting of zirconium oxide, titanium oxide, and magnesium hydroxide is preferable, and magnesium hydroxide is particularly preferable. The inorganic-organic composite film containing these inorganic compound particles in the organic layer has further excellent film strength when used as a diaphragm for electrolyzing alkaline water and a separator for a battery using alkaline water as an electrolytic solution.

Examples of the shape of the inorganic compound particles include an irregular shape, a spherical shape, a cubic shape, a rectangular cuboid shape, a polyhedral shape such as a pot shape, a plate shape such as a disk shape, a flaky shape, and a scale shape, a rod shape, and a fibrous shape. Among them, the plate shape is preferable in that the film strength of the inorganic-organic composite film can be further improved.

The average particle size of the inorganic compound particles is preferably 0.01 μm or more, more preferably 0.05 μm or more, and further preferably 0.1 μm or more. Further, it is preferably 10 μm or less, more preferably 2.0 μm or less, and further preferably 1.5 μm or less.
The average particle size is the volume average particle size (D50) obtained from the particle size distribution measurement by the laser diffraction method. Specifically, the average particle size is obtained by ultrasonically treating the inorganic compound particles in ethanol with a laser diffraction / scattering type particle size distribution measuring device (“Model number LA-920” manufactured by Horiba, Ltd.). It can be obtained by adjusting and measuring the transmittance specified by the device.

The content of the inorganic compound particles is preferably 30% by mass or more, more preferably 32% by mass or more, still more preferably 35% by mass or more, based on 100% by mass of the inorganic organic composite film. .. The content of the inorganic compound particles is preferably 99% by mass or less, more preferably 45% by mass or less, and preferably 43% by mass or less with respect to 100% by mass of the inorganic organic composite film. More preferred.

The content of the organic polymer is preferably 1 part by mass or more, more preferably 22 parts by mass or more, and further preferably 25 parts by mass or more with respect to 100 parts by mass of the inorganic compound particles. , 67 parts by mass or less, more preferably 42 parts by mass or less, still more preferably 40 parts by mass or less.

(Other ingredients)
The organic layer may contain other components in addition to the above-mentioned inorganic compound particles and the organic polymer. Examples of other components include carbon and the like.

The organic layer can be formed by using an organic layer forming material prepared by mixing the above-mentioned inorganic compound particles, an organic polymer, and if necessary, other components with a solvent. The formation of the organic layer will be described in detail in the method for producing an inorganic organic composite film described later.

The thickness of the organic layer is preferably 10 to 1000 μm, more preferably 100 to 500 μm, and even more preferably 200 to 400 μm.

<Support>
In the inorganic-organic composite film of the present invention, the support is a nonwoven fabric having an average fiber diameter of 3 to 20 μm. As described above, by using a specific non-woven fabric having an average fiber diameter within the above range as a support and having the above-mentioned organic layer, an inorganic organic substance having a high film hardness and excellent flexibility is provided. It can be a composite membrane.

The nonwoven fabric preferably has a basis weight of 20 to 150 g / m ² . When the basis weight is within the above range, the flexibility and film strength of the inorganic-organic composite film can be further improved. The basis weight is more preferably 30 to 140 g / m ² , and even more preferably 40 to 130 g / m ² .

The nonwoven fabric preferably contains at least one selected from the group consisting of an aliphatic hydrocarbon polymer and polyphenylene sulfide. That is, the nonwoven fabric is preferably composed of an aliphatic hydrocarbon-based polymer and a fiber containing at least one selected from the group consisting of polyphenylene sulfide.
Examples of the aliphatic hydrocarbon-based polymer include the same as the aliphatic hydrocarbon group-containing polymer used in the above-mentioned organic layer. The nonwoven fabric may contain only one type of the aliphatic hydrocarbon polymer, or may contain two or more types.
Among them, the nonwoven fabric preferably contains a polyolefin-based polymer and / or polyphenylene sulfide, in that the inorganic-organic composite film can exhibit even more excellent film strength and flexibility, and polypropylene. And / or more preferably it contains polyphenylene sulfide.

The non-woven fabric may contain other polymers, but the total content of the aliphatic hydrocarbon-based polymer and polyphenylene sulfide is 85 to 100% by mass with respect to 100% by mass of the polymer components constituting the non-woven fabric. It is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, and particularly preferably 99% to 100% by mass.

The support (that is, the non-woven fabric) preferably has a porosity of 30 to 90% by volume. When the porosity is within the above range, an inorganic-organic composite film having excellent film strength can be obtained. The porosity is more preferably 32 to 85% by volume, further preferably 35 to 80% by volume. Specifically, the porosity can be obtained by the following formula.
Porosity (% by volume) = (1-apparent density / theoretical density determined by material) x 100
Apparent density (g / cm ³ ) = film thickness (μm) x basis weight (g / m ² )

The thickness of the support can be appropriately selected depending on the purpose and application of the inorganic-organic composite film of the present invention, but is preferably 10 to 300 μm, more preferably 50 to 250 μm, still more preferably 100 to 200 μm, for example. ..

The structure of the inorganic-organic composite film of the present invention is not particularly limited as long as it has the above-mentioned organic layer and support, and may be appropriately designed according to the purpose and application, and may be applied to one or both sides of the organic layer. The structure may have the support, or the organic layers may be provided on both sides of the support, but a composite film in which the organic layer and the support are integrated is preferable. .. By integrating the organic layer and the support, the film strength can be further increased. The integration may be a part or all of the organic layer and the support, but it is more preferable that the entire support is integrated with the organic layer.

The total thickness of the inorganic-organic composite film of the present invention may be appropriately designed according to the purpose and application, but is usually 10 to 1000 μm, preferably 10 to 500 μm, more preferably 10 to 300 μm, still more preferably 50 to 250 μm. Particularly preferably, it is 100 to 200 μm.

The inorganic-organic composite film of the present invention preferably has a porosity of 10 to 80% by volume, more preferably 15 to 75% by volume, and even more preferably 20 to 70% by volume. When the porosity is within the above range, when the inorganic-organic composite membrane of the present invention is used as a diaphragm for an electrochemical element, the pores of the diaphragm are continuously filled with the electrolytic solution, so that ionic conductivity, gas barrier properties, etc. It can be an excellent film.
Further, by having a porosity in a predetermined range, it is possible to achieve both higher film strength and excellent flexibility. For example, in the composite film in which the organic layer and the support are integrated, when a hard and brittle material is used, the strength of the inorganic organic composite film can be increased, but the flexibility is lowered, and the film is formed. It is not easy to achieve both strength and flexibility at a high level. In the present invention, by setting the porosity of the inorganic-organic composite film within a predetermined range, it is possible to achieve both film strength and flexibility at a higher level.
The porosity can be determined by immersing the inorganic-organic composite membrane of the present invention in a solution such as an electrolytic solution overnight and measuring the mass of the membrane before and after absorbing the liquid. Specifically, it can be obtained by the following formula.
Porosity (% by volume) = (mass of membrane after immersion-mass of membrane before immersion) / density of solution / volume of membrane x 100

2. 2. Method for Producing Inorganic Organic Composite Film The method for producing the inorganic organic composite film of the present invention is not particularly limited, and the above-mentioned organic layer forming material containing the inorganic compound particles and the organic polymer is rolled on the support by a roll. A known method such as a method of forming a film by forming a film, a method of rolling with a flat plate press or the like to form a film, an injection molding method, an extrusion molding method, a casting method or the like can be applied. .. Further, as a method for efficiently producing a porous inorganic-organic composite film, a non-solvent-induced phase separation method is preferably mentioned.

Examples of the method for producing a porous inorganic-organic composite film by the non-solvent-induced phase separation method include a method including the following steps (1) and (2).
(1) Step of preparing an organic layer forming material containing inorganic compound particles and an organic polymer (2) Step of forming an organic layer on a support using the above organic layer forming material Producing such an inorganic organic composite film. The method, that is, a step of preparing an organic layer forming material containing inorganic compound particles and a polymer (hereinafter, also referred to as “step (1)”), and an organic layer on a support using the above organic layer forming material. A method for producing an inorganic-organic composite film, which comprises a step of forming the above (hereinafter, also referred to as “step (2)”), is also one of the preferred embodiments of the present invention. Each process will be described below.

Process (1)
In the method for producing an inorganic-organic composite film of the present invention, first, an organic layer-forming material containing inorganic compound particles and an organic polymer is prepared.
The method for preparing the organic layer forming material is not particularly limited as long as it is a method capable of mixing the above-mentioned inorganic compound particles and the organic polymer, and a known mixing method can be applied.

When the inorganic compound particles and the organic polymer are mixed, the inorganic compound particles and the organic polymer may be mixed with the solvent at the same time if necessary, or a dispersion liquid (slurry) in which the inorganic compound particles are dispersed in the solvent is prepared in advance. , The organic polymer may be added to the dispersion and mixed, or a solution in which the organic polymer is dissolved in a solvent may be prepared and this solution and the dispersion may be mixed. In particular, in that the inorganic compound particles and the organic polymer can be mixed so as to be more uniform, a dispersion liquid in which the inorganic compound particles are dispersed in a solvent is prepared in advance, and the organic polymer or the organic polymer is added to the dispersion liquid. It is preferable to add a solution in which the polymer is dissolved in a solvent and mix them.

The mixing method is not particularly limited, and known mixing and dispersing means such as a method using a mixer, a ball mill, a jet mill, a dispenser, a sand mill, a roll mill, a pot mill, a paint shaker and the like can be applied.

The solvent for dispersing the inorganic compound particles is not particularly limited as long as it has the property of dissolving the organic polymer, and is, for example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide. , N, N-dimethylformamide, dimethyl sulfoxide and the like. These solvents may be used alone or in combination of two or more. Of these, N-methyl-2-pyrrolidone is preferable because the dispersibility of the inorganic compound particles is further improved.

The content of the inorganic compound particles in the dispersion liquid in which the inorganic compound particles are dispersed in a solvent is preferably 20 to 70% by mass, more preferably 30 to 60% by mass, and 40 to 50% by mass. Is more preferable.

The solvent used in the solution in which the organic polymer is dissolved is not particularly limited as long as it has the property of dissolving the organic polymer, and examples thereof include the same solvent as the solvent for dispersing the inorganic compound particles. be able to. These solvents may be used alone or in combination of two or more. Among them, the same solvent as the solvent used for preparing the dispersion is preferable in that the inorganic compound particles and the organic polymer can be mixed and dispersed so as to be more uniform.

The content of the organic polymer in the solution in which the organic polymer is dissolved is preferably 10 to 50% by mass, more preferably 15 to 40% by mass, and further preferably 20 to 30% by mass. ..

The dispersion liquid and the organic polymer or the solution in which the organic polymer is dissolved may be appropriately mixed in a desired amount according to the purpose and use of the obtained inorganic organic composite film to prepare an organic layer forming material.

Process (2)
In the method for producing an inorganic-organic composite film of the present invention, an organic layer is then formed on a support using the organic layer-forming material obtained in step (1).
The method for forming the organic layer on the support using the organic layer forming material is not particularly limited, but the following steps (2-) can efficiently produce a porous inorganic-organic composite film. It is preferable to include 1) to (2-2).
(2-1) A step of forming a coating film of the organic layer forming material on a support,
(2-2) A step of coagulating the coating film by contacting the coating film with a non-solvent, and (2-3) a step of obtaining an organic layer by drying the solidified coating film.

As described above, the step of forming the organic layer is a step of forming a coating film of the organic layer forming material on the support, a step of coagulating the coating film by contacting the coating film with a non-solvent, and a step of solidifying the coating film. The embodiment including the step of obtaining an organic layer by drying the solidified coating film is also one of the preferred embodiments in the method for producing an inorganic organic composite film of the present invention.

Process (2-1)
Examples of the method for forming the coating film of the organic layer forming material on the support include a method of applying the organic layer forming material obtained above on the support and a method of immersing the support in the organic layer forming material. Examples thereof include a method in which the organic layer forming material adheres to the surface thereof, or a support impregnated with the organic layer forming material is obtained.
Further, the organic layer forming material may be applied on a base material, the support may be placed on the coating liquid, and the support may be impregnated with the coating liquid.

The method for applying the resin mixture is not particularly limited, and known coating means such as a method using die coating, spin coating, gravure coating, curtain coating, dip coating, spray, applicator, coater, etc. shall be applied. Can be done.

The coating amount of the organic layer forming material is not particularly limited, and may be appropriately set so that the thickness of the obtained inorganic organic composite film becomes a thickness according to the purpose and application.

Process (2-2)
The coating film formed in step (2-1) is brought into contact with a non-solvent to solidify the coating film. By bringing the coating film into contact with the non-solvent, the non-solvent diffuses into the coating film, and the polymer that is insoluble in the non-solvent coagulates. On the other hand, the solvent in the coating film dissolved in the non-solvent elutes from the coating film. By such phase separation, the organic polymer solidifies and a porous organic layer is formed.
Examples of the method of bringing the coating film into contact with the non-solvent include a method of immersing the coating film in the non-solvent (coagulation bath).

The non-solvent is not particularly limited as long as it has a property of substantially not dissolving the organic polymer, but for example, water such as ion-exchanged water; lower alcohols such as methanol, ethanol and propyl alcohol; or these. Of these, water is preferable, and ion-exchanged water is more preferable, from the viewpoint of economy and waste liquid treatment. Further, the non-solvent may contain a small amount of the same solvent as the solvent contained in the coating film in addition to the above-mentioned components.

The amount of the non-solvent used is preferably 50 to 10000% by mass with respect to 100% by mass of the solid content (nonvolatile content) of the coating film, that is, the organic layer forming material. It is more preferably 100 to 5000% by mass, and even more preferably 200 to 1000% by mass. In order to adjust the porosity of the obtained inorganic-organic composite film to a preferable range, it is preferable to use a non-solvent in the above-mentioned ratio.

Process (2-3)
By drying the coating film solidified in the above step (2-3) and removing the non-solvent, an inorganic organic composite film having a porous organic layer formed on the support can be obtained.
The drying method is not particularly limited, and can be performed by using known drying means such as heat drying, hot air drying, and vacuum drying.
The drying temperature is preferably 60 to 80 ° C.
The drying time is not particularly limited and may be appropriately designed according to the shape, size and the like of the diaphragm, but is usually 2 to 120 minutes, preferably 5 to 60 minutes, and more preferably 10 to 30 minutes.

As described above, the inorganic-organic composite film of the present invention can be suitably produced by the above-mentioned steps (1) and (2).

3. 3. Applications The inorganic-organic composite film of the present invention has high film strength and excellent flexibility. Therefore, the inorganic-organic composite film of the present invention can be suitably used for applications requiring film strength and flexibility. The inorganic-organic composite membrane of the present invention is particularly preferably used as a diaphragm for alkali water electrolysis, a diaphragm for electrochemical elements such as a battery separator, and the like. Therefore, the inorganic-organic composite film of the present invention is preferably a diaphragm for an electrochemical device. That is, it is a diaphragm for an electrochemical element containing an organic layer containing an organic polymer and a support, wherein the organic layer further contains inorganic compound particles, and the support has an average fiber diameter of 3 to 20 μm. A diaphragm for an electrochemical element, which is characterized by being a non-woven fabric, is also one of the present inventions.
Hereinafter, a preferred form of the diaphragm for alkaline water electrolysis and the battery separator using the inorganic-organic composite film of the present invention will be described.

3-1. Alkaline water electrolysis diaphragm The inorganic organic composite film of the present invention can be suitably used as an alkaline water electrolysis diaphragm. That is, it is an alkaline water electrolysis diaphragm containing an organic layer containing an organic polymer and a support, wherein the organic layer further contains inorganic compound particles, and the support has an average fiber diameter of 3 to 20 μm. A diaphragm for alkaline water electrolysis, which is characterized by being a non-woven fabric, is also one of the preferred embodiments of the present invention.

Examples of the inorganic compound particles in the alkaline water electrolytic diaphragm include the same inorganic compound particles in the above-mentioned "inorganic organic composite film", but among them, the point that the inorganic component is difficult to elute in the alkaline solution. Therefore, metal oxides and / or metal hydroxides are preferable, and metal hydroxides are more preferable.

As the metal oxide and / or metal hydroxide, an oxide of zirconium, magnesium, titanium and / or a hydroxide is preferable, and magnesium hydroxide, zirconium hydroxide, and titanium hydroxide are more preferable.

The average particle size of the inorganic compound particles is preferably 0.05 to 2.0 μm, more preferably 0.1 to 1.5 μm, in terms of good dispersibility with the organic polymer. , 0.2 to 1.0 μm, more preferably. The average particle size can be obtained by the same method as the method for measuring the average particle size of the inorganic compound particles in the above-mentioned "inorganic organic composite film".

As the shape of the inorganic compound particles, the same shape as the inorganic compound particles in the above-mentioned "inorganic organic composite film" can be mentioned.

As the inorganic compound particles, one of the above-mentioned particles may be used alone, or two or more of the above-mentioned particles may be used in combination.

The content of the inorganic compound particles in the alkaline water electrolysis diaphragm is preferably 30 to 90% by mass, more preferably 32 to 85% by mass, still more preferably 35 to 80% by mass.

Examples of the organic polymer in the alkaline water electrolytic diaphragm include the same organic polymers as those in the above-mentioned "inorganic organic composite film", but among them, the aromatic hydrocarbon group-containing polymer is preferable, and polysulfone is preferable. , At least one selected from the group consisting of polyethersulfone, and polyphenylsulfone is more preferred.

The content of the organic polymer in the alkaline water electrolysis diaphragm is preferably 1 to 40% by mass, more preferably 5 to 35% by mass, still more preferably 7 to 30% by mass.

Examples of the support in the diaphragm for alkaline water electrolysis include the same as the support in the above-mentioned "inorganic organic composite membrane".
Among them, the material of the non-woven fabric which is the support in the alkaline water electrolytic diaphragm preferably contains at least one resin selected from the group consisting of polypropylene, polyethylene, and polyphenylene sulfide, and is preferably made of polypropylene and polyethylene. It is more preferable to contain at least one resin selected from the above group.

The thickness of the support in the alkaline water electrolysis diaphragm is preferably 30 to 300 μm, more preferably 50 to 250 μm, and further preferably 100 to 200 μm.

The porosity of the diaphragm for electrolysis of alkaline water is preferably 20 to 80% by volume, more preferably 25 to 75% by volume, and even more preferably 30 to 70% by volume. The porosity can be measured by the same method as the method for measuring the porosity in the above-mentioned "inorganic organic composite film".

The thickness of the alkaline water electrolysis diaphragm is preferably 50 to 1000 μm, more preferably 100 to 500 μm, and even more preferably 200 to 400 μm.

Examples of the method for producing the diaphragm for alkaline water electrolysis include the same method as the method for producing the above-mentioned "inorganic organic composite membrane". Of these, the non-solvent-induced phase separation method is preferable because it can efficiently form a porous membrane.

The diaphragm for alkaline water electrolysis is used as a member of the alkaline water electrolyzer. Examples of the alkaline water electrolyzer include an anode, a cathode, and a diaphragm for alkaline water electrolysis arranged between the anode and the cathode. More specifically, the alkaline water electrolyzer has an anode chamber in which an anode is present and a cathode chamber in which a cathode is present, which are separated by the alkaline water electrolysis diaphragm. Examples of the anode and the cathode include known electrodes including a conductive substrate containing nickel or a nickel alloy or the like.

The method of electrolyzing water using the alkaline water electrolyzer provided with the alkaline water electrolyzing diaphragm is not particularly limited, and a known method can be used. For example, it can be performed by filling the alkaline water electrolyzer equipped with the above-mentioned alkaline water electrolyzing diaphragm with the electrolytic solution and applying an electric current in the electrolytic solution.

As the electrolytic solution, an alkaline aqueous solution in which an electrolyte such as potassium hydroxide or sodium hydroxide is dissolved is used. The concentration of the electrolyte in the electrolytic solution is not particularly limited, but is preferably 20 to 40% by mass in that the electrolytic efficiency can be further improved.

The temperature at the time of electrolysis is preferably 50 to 120 ° C., more preferably 80 to 90 ° C., in that the ion conductivity of the electrolytic solution can be further improved and the electrolytic efficiency can be further improved. The current can be applied under known conditions and methods.

3-2. Battery Separator The inorganic organic composite membrane of the present invention can also be suitably used as a battery separator. That is, it is a battery separator containing an organic layer containing an organic polymer and a support, wherein the organic layer further contains inorganic compound particles, and the support is a nonwoven fabric having an average fiber diameter of 3 to 20 μm. A battery separator characterized by this is also one of the preferred embodiments of the present invention.

Examples of the inorganic compound particles in the battery separator include the same as those in the above-mentioned "inorganic organic composite membrane". Of these, layered double hydroxides and / or oxides are preferable, layered double hydroxides are more preferable, and hydrotalcite is even more preferable, in terms of good ionic conductivity.

The average particle size of the inorganic compound particles in the battery separator is preferably 0.001 to 10 μm, more preferably 0.01 to 5 μm in that it has good dispersibility with the organic polymer. It is more preferably 0.1 to 4 μm. The average particle size can be obtained by the same method as the method for measuring the average particle size of the inorganic compound particles in the above-mentioned "inorganic organic composite film".

The content of the inorganic compound particles in the battery separator is preferably 30 to 99% by mass, more preferably 40 to 95% by mass.

Examples of the organic polymer in the battery separator include the same as the organic polymer in the above-mentioned "inorganic organic composite membrane". Of these, conjugated diene-based polymers and / or (meth) acrylic-based polymers are preferable because they can extend the life of the battery.

The organic polymer used in the battery separator preferably has a weight average molecular weight of 10,000 or more and 6.5 million or less. The weight average molecular weight is more preferably 20,000 or more. The weight average molecular weight can be measured as a polystyrene-converted weight average molecular weight by gel permeation chromatography (GPC) under the following conditions.
Equipment: HCL-8220GPC manufactured by Tosoh Corporation
Column: TSKgel Super AWM-H
Eluent (LiBr · H2O, NMP containing phosphoric acid): 0.01 mol / L

The organic polymer used in the battery separator preferably has a glass transition temperature (Tg) of −40 ° C. or higher and 50 ° C. or lower. If the Tg of the organic polymer is less than −40 ° C., the mechanical strength of the battery separator may decrease. Further, when the Tg exceeds 50 ° C., the battery separator becomes too hard and brittle, and for example, there is a possibility that cracks or the like are likely to enter the battery separator during handling. In the battery separator of the present invention, in order to suppress the formation of voids caused by the aggregation of the inorganic compound particles, the components contained in the organic layer forming material are sufficiently kneaded to suppress the aggregation of the inorganic compound particles. However, it is preferable to make the components of the inorganic compound particles and the organic polymer uniform. When the Tg of the organic polymer is -40 ° C or higher and 50 ° C or lower, the kneaded product becomes more moderately fluid when kneaded with the inorganic compound particles, and the agglomerates of the inorganic compound particles are crushed or an organic layer is formed. The components contained in the material can be made more uniform. The Tg of the organic polymer is more preferably −15 ° C. or higher and 30 ° C. or lower, and further preferably −10 ° C. or higher and 20 ° C. or lower.

The content of the organic polymer in the battery separator is preferably 1 to 70% by mass, more preferably 5 to 60% by mass.

As the support in the battery separator, the same support as in the above-mentioned "inorganic organic composite film" can be mentioned.
Among them, as the material of the non-woven fabric that is the support in the battery separator, a polyolefin-based polymer, a polyvinyl alcohol-based polymer, and polyphenylene sulfide are preferable.

In the battery separator, the organic layer may be formed on one surface of the support or may be formed on both surfaces. Further, it may be a complex in which the organic layer and the support are integrated.

The thickness of the battery separator is preferably 10 to 1000 μm, more preferably 15 to 800 μm, still more preferably 20 to 500 μm.

Examples of the method for manufacturing the battery separator include the same method as the method for manufacturing the above-mentioned "inorganic organic composite film".

The battery separator can be suitably used as a battery separator composed of a positive electrode, a negative electrode, and an electrolytic solution.
The positive electrode is not particularly limited as long as it contains an active material usually used as a positive electrode active material for a primary battery or a secondary battery, and known ones can be used.
Examples of the active material of the positive electrode include oxygen (when oxygen is the active material of the positive electrode, the positive electrode is a perovskite type compound capable of reducing oxygen and oxidizing water, a cobalt-containing compound, an iron-containing compound, a copper-containing compound, and manganese. Containing compound, vanadium-containing compound, nickel-containing compound, iridium-containing compound, platinum-containing compound; palladium-containing compound; gold-containing compound; silver compound; air electrode composed of carbon-containing compound, etc.); Nickel oxyhydroxide, water Nickel-containing compounds such as nickel oxide and cobalt-containing nickel hydroxide; manganese-containing compounds such as manganese dioxide; silver oxide; lithium-containing compounds such as lithium cobaltate; iron-containing compounds; zinc species such as metallic zinc and zinc oxide. Be done. Among them, the zinc compound is preferable in that the performance of the separator can be further enhanced.

The negative electrode is not particularly limited as long as it contains an active material usually used as a negative electrode active material for a primary battery or a secondary battery, and known ones can be used.
As the active material of the negative electrode, a material usually used as a negative electrode active material of a battery, such as carbon, lithium, sodium, magnesium, zinc, nickel, tin, and a silicon-containing material, can be used. Of these, zinc compounds are preferable because they can further improve the performance of the separator.

The electrodes constituting the battery can be manufactured by forming an active material layer on the current collector.
The current collectors that make up the electrodes include (electrolytic) copper foil, copper mesh (expanded metal), foamed copper, punching copper, copper alloys such as brass, brass foil, brass mesh (expanded metal), foamed brass, and punching brass. , Nickel foil, corrosion resistant nickel, nickel mesh (expanded metal), punching nickel, metallic zinc, corrosion resistant metallic zinc, zinc foil, zinc mesh (expanded metal), (punching) steel plate, non-woven fabric with conductivity; Ni, Zn, (Electrolytic) copper foil with Sn, Pb, Hg, Bi, In, Tl, brass, etc. added, copper mesh (expanded metal), foamed copper, punching copper, copper alloys such as brass, brass foil, brass mesh (expanded metal) ), Foamed Brass, Punching Brass, Nickel Foil, Corrosion Resistant Nickel, Nickel Mesh (Expanded Metal), Punching Nickel, Metal Zinc, Corrosion Resistant Metal Zinc, Zinc Foil, Zinc Mesh (Expanded Metal), (Punching) Steel Plate, Non-woven Material; Ni, (Electrolytic) copper foil plated with Zn, Sn, Pb, Hg, Bi, In, Tl, brass, etc., copper mesh (expanded metal), foamed copper, punching copper, copper alloys such as brass, brass foil, brass mesh. (Expanded Metal), Foamed Brass, Punching Brass, Nickel Foil, Corrosion Resistant Nickel, Nickel Mesh (Expanded Metal), Punching Nickel, Metal Zinc, Corrosion Resistant Metal Zinc, Zinc Foil, Zinc Mesh (Expanded Metal), (Punching) Steel Plate, Non-woven ; Silver; Materials used as current collectors and containers for alkaline (storage) batteries and air-zinc batteries.

The electrolytic solution constituting the battery is not particularly limited as long as it is usually used as the electrolytic solution of the battery, and examples thereof include a water-containing electrolytic solution, an organic solvent-based electrolytic solution, and the like, and a water-containing electrolytic solution is preferable. The water-containing electrolytic solution refers to an electrolytic solution (aqueous electrolytic solution) that uses only water as an electrolytic solution raw material, or an electrolytic solution that uses a solution obtained by adding an organic solvent to water as an electrolytic solution raw material.

As the aqueous electrolytic solution, an alkaline electrolytic solution is preferable. Examples of the alkaline electrolytic solution include an aqueous solution of potassium hydroxide, an aqueous solution of sodium hydroxide, an aqueous solution of lithium hydroxide, an aqueous solution of zinc sulfate, an aqueous solution of zinc nitrate, an aqueous solution of zinc phosphate, and an aqueous solution of zinc acetate. The above-mentioned aqueous electrolytic solution can be used alone or in combination of two or more.

Further, the water-containing electrolytic solution may contain an organic solvent used in the organic solvent-based electrolytic solution. Examples of the organic solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, dimethoxymethane, diethoxymethane, dimethoxyethane, tetrahydrofuran, methyltetrahydrofuran, diethoxyethane, dimethyl sulfoxide, sulfolane, acetonitrile, and the like. Examples thereof include benzonitrile, ionic liquids, fluorine-containing carbonates, fluorine-containing ethers, polyethylene glycols, fluorine-containing polyethylene glycols and the like. The organic solvent-based electrolytic solution can be used alone or in combination of two or more. The electrolyte of the organic solvent-based electrolyte 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 are preferable.

In the case of a water-containing electrolyte containing an organic solvent-based electrolyte, the content of the water-based electrolyte is preferably 10 to 99.9% by mass, based on 100% by mass of the total of the water-based electrolyte and the organic solvent-based electrolyte. More preferably, it is 20 to 99.9% by mass.

The form of the battery to which the above battery separator can be applied is as follows: primary battery; secondary battery capable of charging and discharging (storage battery); mechanical culture type battery (battery in which the zinc negative electrode is mechanically replaced); third pole method. Battery (battery composed of a negative electrode, an electrode suitable for charging, and an electrode suitable for discharging), a fuel cell, etc. may be in any form, but a secondary battery or a fuel cell is preferable. ..
The type of the battery is not particularly limited, but a battery using an alkaline electrolyte such as an alkaline dry battery, a silver oxide battery, a manganese-zinc battery, a nickel-zinc battery, a fuel cell, and an air battery is preferable.

As described above, the inorganic-organic composite film of the present invention has high film strength and excellent flexibility. The inorganic-organic composite film of the present invention is suitably used as a diaphragm for alkaline water electrolysis and a battery separator.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "part" means "part by mass" and "%" means "% by mass".

In the examples, various physical property values and the like were measured by the following methods.
(1. Average fiber diameter measurement)
The surface of the non-woven fabric was observed at a magnification of 50 using a laser microscope (manufactured by KEYENCE, model number VK-9700). For the obtained images, the diameters of 30 fibers were measured using analysis software (Image-Pro Premier), and the average value was taken as the average fiber diameter.

(2. Tensile strength test)
A test piece of a diaphragm for an electrochemical element cut out to a size of 1 x 10 cm was allowed to stand for 1 hour in a constant temperature and humidity environment of 23 ° C. and 50%, and then a tensile tester (manufactured by Shimadzu Corporation, model number Autograph AG-1kN XPlus). ) Was used to pull in the MD direction (longitudinal direction of the non-woven fabric and coating direction of the coating liquid) at a distance of 5 cm between the jigs and a speed of 20 cm / min, and the strength at break was measured.

3. 3. Bending test Using a bending tester (mandrel No. 514, model number No. 514, manufactured by Yasuda Seiki Seisakusho Co., Ltd.), a test was performed so that the support of the test piece of the diaphragm for electrochemical elements cut into 2 x 5 cm was inside. It was sandwiched between the receiving plate and the mandrel, bent at 180 ° C. for 2 seconds, and then the presence or absence of cracks on the coating film surface was confirmed using a 10 magnification of a laser microscope (manufactured by KEYENCE, model number VK-9700).

<Example 1>
(1. Preparation of magnesium hydroxide dispersion)
Magnesium hydroxide (manufactured by Kyowa Chemical Industries, Ltd., product number 200-06H, average particle size 0.54 μm) and N-methyl-2-pyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.) are mixed so as to have a mass ratio of 1: 1. A magnesium hydroxide dispersion was prepared by performing a dispersion treatment at room temperature for 6 hours in a pot mill containing zirconia media balls.

(2. Preparation of polysulfone resin solution)
Polysulfone resin solution by thermally dissolving polysulfone resin (manufactured by BASF, product number Ultrazone S3010) in N-methyl-2-pyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.) at a concentration of 30% by mass at 80 to 100 ° C. Was prepared.

(3. Preparation of organic layer forming material)
The magnesium hydroxide dispersion and the polysulfone resin solution obtained above are weighed so that the polysulfone resin (PSU) is 33 parts by mass with respect to 100 parts by mass of magnesium hydroxide. , Part number Awatori Rentaro ARE-500) at room temperature at 1000 rpm for about 10 minutes. The obtained mixed solution was filtered through a 200 mesh of SUS to obtain an organic layer forming material.

(4. Formation of coating film)
The above organic layer forming material is coated on a polyethylene terephthalate (PET) film with an applicator so that the weighing value of the organic layer forming material at the time of drying is 9.0 mg / cm ² , and a polypropylene non-woven fabric (average) is applied thereto. The non-woven fabric was completely impregnated with the organic layer forming material by contacting the non-woven fabric with a fiber diameter of 4.7 μm, a grain of 60 g / m ² , and a film thickness of 160 μm). Then, the nonwoven fabric impregnated with the organic layer forming material was bathed in water at room temperature for 10 minutes to solidify the organic layer forming material to form a coating film, and the coating film was peeled off from the PET film together with the nonwoven fabric in water. After bathing in water, the obtained coating film was dried in a dryer at 80 ° C. for 30 minutes to obtain a diaphragm for an electrochemical element composed of a composite in which the nonwoven fabric and the coating film were integrated. The total thickness of the obtained septum was 210 μm. The porosity of the obtained septum was 40% by volume.
The tensile strength of the obtained diaphragm was 55 N / 10 mm, and no crack was confirmed after the bending test.

<Example 2>
Polyphenylene sulfide non-woven fabric (average fiber diameter 8.2 μm, grain 80 g / m ² , film thickness 160 μm) was used instead of polypropylene non-woven fabric, except that the electrochemical element diaphragm (total thickness 220 μm, total thickness 220 μm) was used in the same manner as in Example 1. Porosity 38% by volume) was prepared. The tensile strength of the obtained diaphragm was 86 N / 10 mm, and no crack was confirmed after the bending test.

<Example 3>
Polyphenylene sulfide non-woven fabric (average fiber diameter 7.6 μm, grain 80 g / m ² , film thickness 100 μm) was used instead of polypropylene non-woven fabric, except that the electrochemical element diaphragm (total thickness 180 μm, total thickness 180 μm) was used in the same manner as in Example 1. Porosity 43% by volume) was prepared. The tensile strength of the obtained diaphragm was 45 N / 10 mm, and no crack was confirmed after the bending test.

<Example 4>
Polyphenylene sulfide non-woven fabric (average fiber diameter 6.7 μm, grain 110 g / m ² , film thickness 190 μm) was used instead of polypropylene non-woven fabric, except that the electrochemical element diaphragm (total thickness 250 μm, total thickness 250 μm) was used in the same manner as in Example 1. Porosity 39% by volume) was prepared. The tensile strength of the obtained diaphragm was 99 N / 10 mm, and no crack was confirmed after the bending test.

<Example 5>
Weigh 100 parts by mass of magnesium hydroxide particles (manufactured by Kyowa Chemical Industry Co., Ltd., product number 200-06H, average particle diameter 0.54 μm), 3 parts by mass of polyacrylate aqueous solution (nonvolatile content 40%), and 42 parts by mass of ion-exchanged water. After being dispersed for 1 hour using a sand mill, filtration was performed to obtain an aqueous dispersion of magnesium hydroxide particles.
After measuring and mixing 50 parts by mass of the obtained aqueous dispersion of magnesium hydroxide particles and 33 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (nonvolatile content: 48%, Narustar SR-152 manufactured by Nippon A & L Inc.). , Filtration and vacuum defoaming were performed to obtain an organic layer forming material.
The obtained organic layer-forming material is coated on a PET film with a comma coater so that the weighing value of the organic layer-forming material at the time of drying is 9.0 mg / cm ² , and a polypropylene non-woven fabric (average) is applied thereto. Fiber diameter 4.7 μm, grain 40 g / m ² , thickness 90 μm), dried, and peeled off the non-woven fabric together with the non-woven fabric from the PET film to integrate the non-woven fabric and the coating film into a diaphragm for electrochemical elements. Got The total thickness of the obtained septum was 130 μm, and the porosity was 17% by volume. The tensile strength of the obtained diaphragm was 51 N / 10 mm, and no crack was confirmed after the bending test.

<Example 6>
A hydrotalcite aqueous dispersion was obtained in the same manner as in Example 5 except that hydrotalcite (manufactured by Kyowa Chemical Industry Co., Ltd., product number DHT-6, average particle diameter 0.20 μm) was used as the inorganic compound particles. An organic layer is formed using 50 parts by mass of this hydrotalcite aqueous dispersion and 21 parts by mass of a carboxy-modified styrene-butadiene polymer aqueous dispersion (nonvolatile content: 48%) prepared by the same method as in Example 5. A diaphragm for an electrochemical element (total thickness 120 μm, pore ratio 19% by mass) was obtained by the same method as in Example 5 except that the material was obtained. The tensile strength of the obtained diaphragm was 48 N / 10 mm, and no crack was confirmed after the bending test.

<Example 7>
A diaphragm for an electrochemical element (total thickness 150 μm, pores) was used in the same manner as in Example 5 except that a polyvinyl alcohol non-woven fabric (average fiber diameter 17.1 μm, grain 25 g / m ² , thickness 90 μm) was used instead of the polypropylene non-woven fabric. A rate of 19% by volume) was obtained. The tensile strength of the obtained diaphragm was 41 N / 10 mm, and no crack was confirmed after the bending test.

<Comparative Example 1>
As the polypropylene non-woven fabric, a diaphragm for an electrochemical element (total thickness 220 μm, porosity 38% by volume) was used in the same manner as in Example 1 except that a polypropylene non-woven fabric having an average fiber diameter of 2.2 μm, a grain size of 50 g / m ² , and a film thickness of 160 μm was used. ) Was obtained. The tensile strength of the obtained diaphragm was 11 N / 10 mm, and no crack was confirmed after the bending test.

<Comparative Example 2>
A polypropylene non-woven fabric having an average fiber diameter of 21.5 μm, a grain size of 60 g / m ² , and a film thickness of 180 μm was used in the same manner as in Example 1 to form a diaphragm for an electrochemical element (total thickness 250 μm, porosity 42 volume%). ) Was obtained. The tensile strength of the obtained septum was 120 N / 10 mm, and several cracks of about 10 μm were confirmed after the bending test.

Claims (1)

A film containing an organic layer containing an organic polymer and a support.
The organic layer further contains inorganic compound particles and contains
The support is a non-woven fabric having an average fiber diameter of 3 to 20 μm .
The inorganic compound particles are at least one selected from the group consisting of magnesium hydroxide, zirconium hydride, and titanium hydroxide.
The basis weight of the nonwoven fabric is 40 to 150 g / m ² .
A diaphragm for alkaline water electrolysis, which is characterized by this.