JP2009193761A - Reactive polymer-supporting porous film for battery separator, and electrode/separator assembly obtained therefrom - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactive polymer-supporting porous film for a battery separator that achieves a battery excellent in safety at high temperature because of sufficient adhesiveness to an electrode and excellent heat resistance. <P>SOLUTION: The reactive polymer-supporting porous film for a battery separator is characterized by supporting a reactive polymer on a porous film that includes a cross-linked body of a resin composition containing polyolefin and a styrene-butadiene copolymer and a gel fraction of 5% or higher, and obtaining the reactive polymer from a cross-linked polymer obtained by reacting the cross-linked polymer having a plurality of reactive groups selected from 3-oxetanyl and epoxy groups in a molecule with at least one cross-linking agent selected from acid anhydride, polycarboxylic acid and monocarboxylic acid to be partially cross-linked via some of its reactive groups. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reactive polymer-supported porous film for a battery separator and an electrode / separator assembly obtained therefrom.

  In recent years, lithium ion secondary batteries having a high energy density have been widely used as power sources for small to portable electronic devices such as mobile phones and notebook personal computers. Such a lithium ion secondary battery is obtained by laminating or winding sheet-like positive and negative electrodes and, for example, a polyolefin resin porous film, and charging the battery into a battery container made of, for example, a metal can. It is manufactured through a process of injecting an electrolytic solution into a container, sealing, and sealing.

  However, in recent years, there has been a strong demand for further downsizing and weight reduction of the above-described small or portable electronic devices. Therefore, further thinning and weight reduction of lithium ion secondary batteries are also required. In place of the conventional metal can container, a laminate seal type battery container is also used.

  According to such a laminated seal type battery container, since the surface pressure for maintaining the electrical connection between the separator and the electrode cannot be sufficiently applied to the electrode surface as compared with the conventional metal can container, Due to the expansion and contraction of the electrode active material during charging and discharging, the distance between the electrodes partially increases with time, the internal resistance of the battery increases, the battery characteristics deteriorate, and the resistance varies within the battery. However, there arises a problem that the battery characteristics are deteriorated.

  Further, when manufacturing a sheet battery having a large area, the distance between the electrodes cannot be kept constant, and there is a problem that battery characteristics cannot be sufficiently obtained due to variations in resistance inside the battery.

  Therefore, conventionally, in order to solve such problems, it has been proposed to join an electrode and a separator by an adhesive resin layer comprising an electrolyte phase, a polymer gel layer containing an electrolyte solution, and a polymer solid layer. (For example, refer to Patent Document 1). In addition, after applying a binder resin solution containing polyvinylidene fluoride resin as a main component to the separator, an electrode is superimposed on the separator and dried to form a battery laminate, and after charging the battery laminate into a battery container, It has also been proposed to obtain a battery in which an electrolyte is injected into a battery container and an electrode is bonded to a separator (see, for example, Patent Document 2).

  Further, the separator impregnated with the electrolytic solution and the positive and negative electrodes are joined and adhered by the porous adhesive resin layer, and the electrolytic solution is held in the through-hole in the adhesive resin layer, thereby separating the separator. It has also been proposed to use a battery in which an electrode is bonded to the battery (see, for example, Patent Document 3).

However, according to such a method, in order to obtain a sufficient adhesive force between the separator and the electrode, the thickness of the adhesive resin layer must be increased, and the electrolytic solution for the adhesive resin Since the amount cannot be increased, the resulting battery has a problem that the internal resistance becomes high and the cycle characteristics and the high rate discharge characteristics cannot be sufficiently obtained.
JP-A-10-177865 Japanese Patent Laid-Open No. 10-189054 JP-A-10-172606

  The present invention has been made to solve the above-described problems in the production of a battery in which an electrode is bonded to a separator, and has sufficient adhesiveness with the electrode and is excellent in heat resistance. Another object of the present invention is to provide a reactive polymer-supported porous film for a battery separator that provides a battery with excellent safety at high temperatures.

  Furthermore, an object of the present invention is to provide an electrode / separator assembly obtained from such a crosslinkable polymer-supported porous film.

  According to the present invention, there is provided a reactive polymer-supported porous film for a battery separator in which a reactive polymer is supported on a porous film, the porous film comprising a polyolefin and a styrene-butadiene copolymer. Part of a crosslinkable polymer comprising a cross-linked product of a resin composition comprising a gel fraction of 5% or more and having a plurality of reactive groups selected from 3-oxetanyl groups and epoxy groups in the molecule By the reactive group, the reactive polymer is formed from a crosslinked polymer obtained by reacting and partially crosslinking with at least one crosslinking agent selected from acid anhydride, polycarboxylic acid and monocarboxylic acid. A reactive polymer-supported porous film for a battery separator is provided.

  Furthermore, according to the present invention, an electrode is laminated on the reactive polymer-supported porous film to obtain an electrode / reactive polymer-supported porous film laminate, and this electrode / reactive polymer-supported porous film laminate is obtained. After charging into the battery container, an electrolytic solution containing a cationic polymerizable catalyst is injected into the battery container, and the reactive polymer of the electrode / reactive polymer-supported porous film laminate is brought into contact with the electrolytic solution. An electrode / separator assembly obtained by cationic polymerization of the reactive polymer is provided.

  A reactive polymer-supported porous film for a battery separator according to the present invention is a reactive polymer-supported porous film for a battery separator obtained by supporting a reactive polymer on a porous film, The film is made of a crosslinked resin composition containing a polyolefin and a styrene-butadiene copolymer, and has a gel fraction of 5% or more, and a reaction selected from a 3-oxetanyl group and an epoxy group in the molecule. A crosslinkable polymer having a plurality of functional groups is obtained by reacting with at least one crosslinker selected from acid anhydrides, polycarboxylic acids and monocarboxylic acids, and partially crosslinking with some of the reactive groups. The above-mentioned reactive polymer is formed from the resulting crosslinked polymer. Therefore, such a reactive polymer has the unreacted reactive group in the molecule.

  Therefore, an electrode is laminated on such a reactive polymer-supported porous film to form an electrode / reactive polymer-supported porous film laminate, which is charged into a battery container, and then an electrolytic solution containing a cationic polymerization catalyst is prepared. By injecting into the battery container, bringing the reactive polymer of the electrode / reactive polymer-supported porous film laminate into contact with the electrolytic solution, and cationically polymerizing the reactive polymer with the reactive group. A battery having an electrode / porous film assembly formed by firmly bonding a porous film and an electrode can be obtained.

  Furthermore, according to the reactive polymer-supported porous film of the present invention, since the reactive polymer is partially crosslinked in advance, when the electrode / reactive polymer-supported porous film laminate is immersed in the electrolytic solution, Elution and diffusion of the reactive polymer from the electrode / reactive polymer-supported porous film laminate into the electrolyte solution is suppressed, and the reactive polymer swells, and as a result, a small amount of the reactive polymer is used. Thus, an electrode / separator assembly in which the electrode is firmly bonded to the porous film (separator) can be obtained, and the porous film has excellent ion permeability and functions well as a separator. Further, the reactive polymer is not excessively eluted and diffused into the electrolytic solution, and does not adversely affect the electrolytic solution.

  Thus, according to the present invention, an electrode / separator assembly having strong adhesion between the electrode / separator is formed in situ in the battery manufacturing process, and a battery having low internal resistance and excellent high rate characteristics can be easily obtained. Can get to.

  A reactive polymer-supported porous film for a battery separator according to the present invention is a reactive polymer-supported porous film for a battery separator obtained by supporting a reactive polymer on a porous film, The film is made of a crosslinked resin composition containing a polyolefin and a styrene-butadiene copolymer, and has a gel fraction of 5% or more, and a reaction selected from a 3-oxetanyl group and an epoxy group in the molecule. A crosslinkable polymer having a plurality of functional groups is obtained by reacting with at least one crosslinker selected from acid anhydrides, polycarboxylic acids and monocarboxylic acids, and partially crosslinking with some of the reactive groups. The above-mentioned reactive polymer is formed from the resulting crosslinked polymer.

  In the reactive polymer-supported porous film for battery separator according to the present invention, the base porous film is a gel of 5% or more comprising a cross-linked product of a resin composition containing a polyolefin resin and a styrene-butadiene copolymer. It is a porous film having a fraction. Such a porous film is prepared by, for example, producing a porous film from a resin composition containing a polyolefin resin and a styrene-butadiene copolymer, heat-treating the film, or irradiating with an electron beam or an ultraviolet ray to form the double bond. Can be obtained by reacting to give a cross-linked structure.

  The polyolefin resin is preferably a polyethylene resin. For example, a high density polyethylene resin, an ultrahigh molecular weight polyethylene resin, or a mixture thereof is preferably used. The styrene-butadiene copolymer may be a random copolymer, but is preferably a block copolymer. The resin composition containing such a polyolefin resin and a styrene-butadiene copolymer may contain other resins as necessary in order to improve the molding processability and adhesion. An example of such a resin is a modified polyolefin resin obtained by graft polymerization of maleic anhydride onto polyethylene or polypropylene.

  In the present invention, such a porous film has a gel fraction of 5% or more. When the gel fraction is less than 5%, the film resistance at high temperatures is insufficient, and when the battery is exposed to high temperatures, the separator may be broken, leading to a short circuit of the electrodes. In the present invention, the gel fraction of the porous film is in the range of 5 to 90%, preferably in the range of 5 to 70%.

  According to the present invention, the porous film usually has pores having an average pore diameter of 0.01 to 5 μm and a porosity in the range of 20 to 95%. The porosity of the porous film is preferably in the range of 30 to 90%, and most preferably in the range of 40 to 85%. When the porosity of the porous film is too low, when used as a battery separator, the ion conduction path is reduced and sufficient battery characteristics cannot be obtained. On the other hand, when the porosity is too high, when used as a battery separator, the strength is insufficient, and in order to obtain the required strength, a thick substrate porous film must be used. This is not preferable because the internal resistance of the battery increases.

  Further, according to the present invention, the porous film usually has an air permeability of 1500 seconds / 100 cc or less, preferably 1000 seconds / 100 cc or less. When the air permeability is too high, ion conductivity is low when used as a battery separator, and sufficient battery characteristics cannot be obtained.

  The strength of the porous film is preferably 1 N or more in terms of piercing strength. This is because when the piercing strength is less than 1N, the base material may be broken when a surface pressure is applied between the electrodes, thereby causing an internal short circuit.

  In the present invention, the crosslinkable polymer refers to a polymer having a plurality of at least one reactive group selected from a 3-oxetanyl group and an epoxy group in the molecule. A reactive polymer can be obtained by causing the reactive group to react with at least one crosslinking agent selected from an acid anhydride, a polycarboxylic acid, and a monocarboxylic acid, and partially crosslinking the reactive polymer. The reactive polymer-supported porous film for a battery separator according to the present invention can be obtained by supporting the reactive polymer on the substrate porous film.

  According to the present invention, the crosslinkable polymer is preferably at least one radical polymerizable monomer selected from a radical polymerizable monomer having a 3-oxetanyl group and a radical polymerizable monomer having an epoxy group and another radical polymerization. It can be obtained by radical copolymerization with a functional monomer.

  Particularly preferably, in the present invention, the crosslinkable polymer is a polymer having a plurality of 3-oxetanyl groups and epoxy groups as reactive groups in the molecule, or a 3-oxetanyl group and epoxy group in the molecule, respectively. Therefore, the crosslinkable polymer is preferably a radical polymerizable monomer having a 3-oxetanyl group (3-oxetanyl group-containing radical polymerizable monomer) and a radical polymerizable monomer having an epoxy group ( Epoxy group-containing radical polymerizable monomer) and other radical polymerizable monomer, or 3-oxetanyl group-containing radical polymerizable monomer and epoxy group-containing radical polymerizable monomer and other radical polymerizable monomer Can be obtained by radical copolymerization.

  As described above, polymers having a 3-oxetanyl group or an epoxy group in the molecule are already known as described in, for example, JP-A Nos. 2002-110245 and 2001-176555.

  In particular, according to the present invention, the 3-oxetanyl group-containing radical polymerizable monomer is preferably represented by the general formula (I)

(In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
The 3-oxetanyl group containing (meth) acrylate represented by these is used.

  Specific examples of such a 3-oxetanyl group-containing (meth) acrylate include, for example, 3-oxetanylmethyl (meth) acrylate, 3-methyl-3-oxetanylmethyl (meth) acrylate, 3-ethyl-3-oxetanylmethyl ( Examples include meth) acrylate, 3-butyl-3-oxetanylmethyl (meth) acrylate, and 3-hexyl-3-oxetanylmethyl (meth) acrylate. These (meth) acrylates are used alone or in combination of two or more.

  Further, according to the present invention, the epoxy group-containing radical polymerizable monomer is preferably represented by the general formula (II)

(In the formula, R ₃ represents a hydrogen atom or a methyl group, and R ₄ represents the formula (1)

Or formula (2)

The epoxy group containing group represented by these is shown. )
The epoxy group containing (meth) acrylate represented by these is used.

  Specific examples of such an epoxy group-containing (meth) acrylate include, specifically, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, and the like. These (meth) acrylates are used alone or in combination of two or more.

  The other radical polymerizable monomer copolymerized with such a 3-oxetanyl group-containing radical polymerizable monomer or an epoxy group-containing radical polymerizable monomer is preferably represented by the general formula (III)

(In the formula, R ₅ represents a hydrogen atom or a methyl group, A represents an oxyalkylene group having 2 or 3 carbon atoms (preferably, an oxyethylene group or an oxypropylene group), and R ₆ represents 1 to 1 carbon atoms. 6 represents an alkyl group having 6 carbon atoms or a fluorinated alkyl group having 1 to 6 carbon atoms, and n represents an integer of 0 to 12.)
(Meth) acrylate represented by the general formula (IV)

(In the formula, R ₇ represents a methyl group or an ethyl group, and R ₈ represents a hydrogen atom or a methyl group.)
It is at least 1 sort (s) chosen from vinyl ester represented by these.

  Specific examples of the (meth) acrylate represented by the general formula (III) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2,2,2 -Trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, etc. can be mentioned.

  Besides these, for example,

Etc. In the formula, R ₅ represents a hydrogen atom or a methyl group, and n is an integer of 0 to 12.

  Specific examples of the vinyl ester represented by the general formula (IV) include vinyl acetate and vinyl propionate.

  Thus, as described above, the crosslinkable polymer having a plurality of reactive groups in the molecule is preferably a radical having a 3-oxetanyl group and / or epoxy group-containing radical polymerizable monomer and another radical polymerizable monomer as a radical. A radical copolymer can be obtained by radical copolymerization using a polymerization initiator. This radical copolymerization may be carried out by any polymerization method such as solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, etc., but solution polymerization or suspension polymerization in terms of ease of polymerization, adjustment of molecular weight, post-treatment, etc. Is preferred.

  The radical polymerization initiator is not particularly limited, and examples thereof include N, N′-azobisisobutyronitrile, dimethyl N, N′-azobis (2-methylpropionate), and benzoyl peroxide. Lauroyl peroxide is used. In this radical copolymerization, a molecular weight modifier such as mercaptan can be used as necessary.

  According to the present invention, the crosslinkable polymer as described above is reacted with a crosslinker through a part of the reactive groups, and the partially crosslinked polymer is supported on the substrate porous film. The electrode is laminated to form an electrode / reactive polymer-supported porous film laminate, which is immersed in an electrolytic solution containing a cationic polymerization catalyst, preferably an electrolytic solution containing an electrolyte that also serves as a cationic polymerization catalyst. / Reactive polymer-supported porous film laminate is brought into contact with the above electrolytic solution, and a part of the reactive polymer is swollen in the electrolytic solution, or eluted and diffused in the electrolytic solution, The electrode and the porous film can be bonded together by crosslinking by polymerization and gelling the electrolyte near the interface between the porous film and the electrode.

  Therefore, according to the present invention, when obtaining a crosslinkable polymer containing a 3-oxetanyl group and / or an epoxy group, the 3-oxetanyl group-containing radical polymerizable monomer and / or the epoxy group-containing radical polymerizable monomer are: The total amount is 5 to 50% by weight of the total monomer amount, preferably 10 to 30% by weight. Therefore, in the case of obtaining a crosslinkable polymer containing a 3-oxetanyl group, the 3-oxetanyl group-containing radical polymerizable monomer is in the range of 5 to 50% by weight, preferably 10 to 30% by weight of the total monomer amount. In the same manner, in the case of obtaining a crosslinkable polymer containing an epoxy group, the epoxy group-containing radical polymerizable monomer is 5 to 50% by weight, preferably 10 to 30% by weight of the total monomer amount. Used in a range.

  Further, a crosslinkable polymer having a 3-oxetanyl group and an epoxy group by using a 3-oxetanyl group-containing radical polymerizable monomer and an epoxy group-containing radical polymerizable monomer together and copolymerizing these with another radical polymerizable monomer Is used such that the proportion of the epoxy group-containing radical polymerizable monomer in the total amount of the 3-oxetanyl group-containing radical polymerizable monomer and the epoxy group-containing radical polymerizable monomer is 90% by weight or less.

  When obtaining a 3-oxetanyl group-containing crosslinkable polymer or an epoxy group-containing crosslinkable polymer, the total amount of the 3-oxetanyl group-containing radical polymerizable monomer and the epoxy group-containing radical polymerizable monomer is more than 5% by weight of the total monomer amount. When the amount is small, as described above, the amount of the reactive polymer required for gelation of the electrolytic solution is increased, so that the performance of the obtained battery is deteriorated. On the other hand, when it is more than 50% by weight, the retention property of the electrolyte solution of the formed gel is lowered, and the adhesion between the electrode / separator in the obtained battery is lowered.

  In the present invention, the crosslinkable polymer preferably has a weight average molecular weight of 10,000 or more. When the weight average molecular weight of the crosslinkable polymer is smaller than 10,000, a large amount of reactive polymer is required to gel the electrolytic solution, so that the characteristics of the obtained battery are deteriorated. On the other hand, the upper limit of the weight average molecular weight of the crosslinkable polymer is not particularly limited, but is about 3 million, preferably about 2.5 million so that the electrolytic solution can be held as a gel. In particular, according to the present invention, the crosslinkable polymer preferably has a weight average molecular weight in the range of 100,000 to 2,000,000.

  As already known, a 3-oxetanyl group or an epoxy group can react with a carboxyl group or an acid anhydride group and can be cationically polymerized. According to the present invention, a crosslinkable polymer having at least one reactive group selected from 3-oxetanyl group and epoxy group in the molecule by utilizing such reactivity of 3-oxetanyl group and epoxy group. First, a part of these reactive groups is used to react with a carboxylic acid or acid anhydride, which is a cross-linking agent, and a part thereof is cross-linked to form a reactive polymer, which is supported on the porous substrate film. Thus, a reactive polymer-supported porous film for a battery separator is obtained.

  According to the present invention, it is desirable that the reactive polymer obtained by partially crosslinking the crosslinkable polymer in this way has an insoluble fraction in the range of 5 to 80%. Here, the insoluble fraction is, as will be described later, a porous film carrying a reactive polymer immersed in a mixed solvent of ethylene carbonate / diethyl carbonate (volume ratio 1/1) at room temperature with stirring for 2 hours. Thereafter, it refers to the ratio of the reactive polymer remaining on the porous film when immersed in ethyl methyl carbonate.

  When the insoluble fraction of the reactive polymer is less than 5%, an electrode is pressure-bonded to a porous film supporting such a reactive polymer to form an electrode / porous film laminate, which is used as an electrolyte solution. When immersed, most of the reactive polymer elutes and diffuses into the electrolyte, and even if the reactive polymer is further cationically polymerized and crosslinked, effective adhesion can be obtained between the electrode and the porous film. Can not. On the other hand, when the insoluble fraction of the reactive polymer is more than 80%, an electrode / porous film laminate is formed, and when this is immersed in an electrolytic solution, the reactive polymer has low swelling and the resulting electrode / porous A battery having a quality film assembly has a high internal resistance, which is not preferable for battery characteristics. In particular, according to the present invention, the insoluble fraction of the reactive polymer is preferably in the range of 10-60%, and most preferably in the range of 10-50%.

  In the present invention, as described above, at least one selected from monocarboxylic acids, polycarboxylic acids, and acid anhydrides is used as a crosslinking agent for partially crosslinking the crosslinkable polymer.

  Thus, there is no limitation to reacting a crosslinkable polymer with a mono- or polycarboxylic acid and partially crosslinking to obtain a reactive polymer having an insoluble fraction in the range of 5 to 80%. However, the carboxyl group of the mono- or polycarboxylic acid is usually 0.01 to 1.0 mole part, preferably 0.05 to 0.9 mole relative to 1 mole part of the reactive group of the crosslinkable polymer. It is only necessary to adjust the heating reaction conditions between the crosslinkable polymer and the mono- or polycarboxylic acid, and thus a reactive polymer having a desired insoluble content can be obtained.

  As an example, the carboxyl group of the mono- or polycarboxylic acid is used in an amount of 0.5 to 1.0 mol part with respect to 1 mol part of the reactive group of the cross-linkable polymer. A reactive polymer having an insoluble fraction of 5 to 80% can be obtained by heating and reacting with a polycarboxylic acid at 50 ° C. for 10 to 500 hours, usually 12 to 250 hours.

  On the other hand, to obtain a reactive polymer having an insoluble fraction in the range of 5 to 80% by reacting a crosslinkable polymer with an acid anhydride and partially crosslinking to obtain a reactive polymer, The acid anhydride group of the acid anhydride is 0.005 to 0.5 mol part, preferably 0.01 to 0.4 mol part with respect to 1 mol part of the reactive group of the crosslinkable polymer. The heating reaction conditions between the crosslinkable polymer and the acid anhydride may be adjusted.

  As an example, the crosslinkable polymer and acid anhydride are used so that the acid anhydride group of the acid anhydride is 0.25 to 0.1 mol part with respect to 1 mol part of the reactive group of the crosslinkable polymer. A reactive polymer having an insoluble fraction of 5 to 80% can be obtained by subjecting the product to a heat reaction at 50 ° C. for 10 to 500 hours.

  In the present invention, the monocarboxylic acid is an organic acid having one carboxyl group in the molecule, and any monocarboxylic acid can be used without particular limitation. Examples of such molar carboxylic acids include aliphatic monocarboxylic acids, aromatic monocarboxylic acids, and alicyclic monocarboxylic acids. Such a monocarboxylic acid may be a saturated compound or an unsaturated compound, and has an inert substituent such as an alkyl group, a hydroxy group, an alkoxy group, an amino group, or a nitro group in the molecule. May be.

  Accordingly, specific examples of saturated aliphatic monocarboxylic acids include, for example, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid, isocaproic acid, 2-methylvaleric acid, 2-ethylbutyric acid , Heptanoic acid, caprylic acid, 2-ethylhexanoic acid, nonanoic acid, caprylic acid, undecylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, etc. Specific examples of unsaturated aliphatic monocarboxylic acids As, for example, propiolic acid, acrylic acid, crotonic acid, methacrylic acid, pentenoic acid, hexenoic acid, sorbic acid, heptenoic acid, undecylenic acid, linolenic acid, linoleic acid, linoelaidic acid, elaidic acid, oleic acid, ricinoleic acid, Examples include arachidonic acid.

  Furthermore, specific examples of the aromatic monocarboxylic acid include, for example, benzoic acid, toluic acid, ethyl benzoic acid, propyl benzoic acid, isopropyl benzoic acid, butyl benzoic acid, isobutyl benzoic acid, sec-butyl benzoic acid, tert-butyl. Benzoic acid, hydroxybenzoic acid, anisic acid, ethoxybenzoic acid, propoxybenzoic acid, isopropoxybenzoic acid, butoxybenzoic acid, isoptoxybenzoic acid, sec-butoxybenzoic acid, tert-butoxybenzoic acid, aminobenzoic acid, N-methyl Aminobenzoic acid, N-ethylaminobenzoic acid, N-propylaminobenzoic acid, N-isopropylaminobenzoic acid, N-butylaminobenzoic acid, N-isobutylaminobenzoic acid, N-secondary butylaminobenzoic acid, N- Tertiary butylaminobenzoic acid, N, N-dimethylaminobenzoic acid, N, N-di Chiruamino benzoate, nitrobenzoic acid, resorcinol acid, phenylacetic acid, and benzyl acetate.

  Specific examples of the alicyclic monocarboxylic acid include, for example, cyclopropanecarboxylic acid, cyclobutanecarboxylic acid, cyclopentanecarboxylic acid, 1-methylcyclopentanecarboxylic acid, 2-methylcyclopentanecarboxylic acid, and 3-methylcyclopentane. Carboxylic acid, 1-phenylcyclopentanecarboxylic acid, cyclopentenecarboxylic acid, cyclohexanecarboxylic acid, 1-methylcyclohexanecarboxylic acid, 2-methylcyclohexanecarboxylic acid, 3-methylcyclohexanecarboxylic acid, 4-methylcyclohexanecarboxylic acid, 4-propyl Cyclohexanecarboxylic acid, 4-butylcyclohexanecarboxylic acid, 4-pentylcyclohexanecarboxylic acid, 4-hexylcyclohexanecarboxylic acid, 4-phenylcyclohexanecarboxylic acid, 1-pheny List cyclohexanecarboxylic acid, cyclohexenecarboxylic acid, 4-butylcyclohexenecarboxylic acid, cycloheptanecarboxylic acid, 1-cycloheptenecarboxylic acid, 1-methylcycloheptanecarboxylic acid, 4-methylcycloheptanecarboxylic acid, cyclohexylacetic acid, etc. Can do.

  In the present invention, the polycarboxylic acid has 2 or more carboxyl groups in the molecule, preferably 2 to 6, particularly preferably 2 to 4 carboxyl groups in the molecule. It is an organic compound.

  Examples of the dicarboxylic acid having two carboxyl groups in the molecule include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid. C2-C20 straight chain aliphatic saturated dicarboxylic acid, methylmalonic acid, such as acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, eicosandioic acid, 3 carbon atoms such as ethylmalonic acid, n-propylmalonic acid, n-butylmalonic acid, methylsuccinic acid, ethylsuccinic acid, 2,4-diethylglutaric acid, 1,1,3,5-tetramethyloctylsuccinic acid, etc. 20 branched chain aliphatic saturated dicarboxylic acids, maleic acid, fumaric acid, citraconic acid, γ-methylcitraconic acid, mesa Acids, γ-methyl mesaconic acid, itaconic acid, glutaconic acid and other linear or branched aliphatic unsaturated dicarboxylic acids, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, methylhexahydroxyphthalic acid, methylhexa Tetrahydrophthalic acid such as isophthalic acid, methylhexahydroterephthalic acid, cyclohexene-1,2-dicarboxylic acid, cyclohexene-1,6-dicarboxylic acid, cyclohexene-3,4-dicarboxylic acid, cyclohexene-4,5-dicarboxylic acid, Tetrahydroisophthalic acid such as cyclohexene-1,3-dicarboxylic acid, cyclohexene-1,5-dicarboxylic acid, cyclohexene-3,5-dicarboxylic acid, cyclohexene-1,4-dicarboxylic acid, cyclohexene-3,6-dicarboxylic acid, etc. Tetrahydr Terephthalic acid, 1,3-cyclohexadiene-1,2-dicarboxylic acid, 1,3-cyclohexadiene-1,6-dicarboxylic acid, 1,3-cyclohexadiene-2,3-dicarboxylic acid, 1,3-cyclo Dihydrophthalic acid such as hexadiene-5,6-dicarboxylic acid, 1,4-cyclohexadiene-1,2-dicarboxylic acid, 1,4-cyclohexadiene-1,6-dicarboxylic acid, 1,3-cyclohexadiene-1 , 3-dicarboxylic acid, dihydroisophthalic acid such as 1,3-cyclohexadiene-3,5-dicarboxylic acid, 1,3-cyclohexadiene-1,4-dicarboxylic acid, 1,3-cyclohexadiene-2,5- Dicarboxylic acids, 1,4-cyclohexadiene-1,4-dicarboxylic acid, 1,4-cyclohexadiene-3,6-dicarboxylic acid, etc. Loterephthalic acid, methyltetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, endocis-bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic acid, methyl-endocis-bicyclo [2.2.1] hept Saturated or unsaturated carboxylic acids such as -5-ene-2,3-dicarboxylic acid, chlorendic acid, phthalic acid, terephthalic acid, isophthalic acid, 3-methylphthalic acid, 3-ethylphthalic acid, 3-n-propylphthalic acid Acid, 3-isopropylphthalic acid, 3-n-butylphthalic acid, 3-isobutylphthalic acid, 3-s-butylphthalic acid, 3-t-butylphthalic acid and the like 3-alkylphthalic acid, 2-methylphthalic acid, 4-ethylphthalic acid Acid, 4-n-propylphthalic acid, 4-isopropylpyrphthalic acid, 4-n-butylphthalic acid, 4-isobutylphenol 4-alkylphthalic acid such as taric acid, 4-s-butylphthalic acid, 4-t-butylphthalic acid, 2-methylisophthalic acid, 2-ethylisophthalic acid, 2-n-propylphthalic acid, 2-isopropylpyrphthalic acid Acid, 2-n-butylphthalic acid, 2-isobutylphthalic acid, 2-s-butylphthalic acid, 2-alkylphthalic acid such as 2-t-butylphthalic acid, 4-methylisophthalic acid, 4-ethylisophthalic acid, 4- 4-alkylisophthalic acid such as n-propylisophthalic acid, 4-isopropylpyroisophthalic acid, 4-n-butylisophthalic acid, 4-isobutylisophthalic acid, 4-s-butylisophthalic acid, 4-t-butylisophthalic acid, etc. 5-methylisophthalic acid, 5-ethylisophthalic acid, 5-n-propylisophthalic acid, 5-isopropyl-isophthalic acid, 5-n-butyl 5-alkylisophthalic acid such as ruisophthalic acid, 5-isobutylisophthalic acid, 5-s-butylisophthalic acid, 5-t-butylisophthalic acid, methyl terephthalic acid, ethyl terephthalic acid, n-propyl terephthalic acid, isopropyl terephthalephthalate Acids, alkyl terephthalic acids such as n-butyl terephthalic acid, isobutyl terephthalic acid, s-butyl terephthalic acid, t-butyl terephthalic acid, naphthalene-1,2-dicarboxylic acid, naphthalene-1,3-dicarboxylic acid, naphthalene-1 , 4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-1,6-dicarboxylic acid, naphthalene-1,7-dicarboxylic acid, naphthalene-1,8-dicarboxylic acid, naphthalene-2,3-dicarboxylic acid , Naphthalene-2,6-dicarboxylic acid, naphthalene-2,7 Dicarboxylic acid, anthracene-1,3-dicarboxylic acid, anthracene-1,4-dicarboxylic acid, anthracene-1,5-dicarboxylic acid, anthracene-1,9-dicarboxylic acid, anthracene-2,3-dicarboxylic acid, anthracene- Specific examples include aromatic dicarboxylic acids such as 9,10-dicarboxylic acid, 2,2′-bis (carboxykiphenyl) hexafluoropropane, and the like.

  Examples of the polycarboxylic acid having three or more carboxyl groups in the molecule include aliphatic tricarboxylic acids such as tricarballylic acid, citric acid, isocitric acid and aconitic acid, aromatic tricarboxylic acids such as hemimellitic acid and trimellitic acid, C4-C13 aliphatic tetracarboxylic acid such as 2,3,4-butanetetracarboxylic acid, alicyclic tetracarboxylic acid such as maleated methylcyclohexenetetracarboxylic acid, merophanic acid, prenitic acid, pyromellitic acid, Specific examples include aromatic tetracarboxylic acids such as benzophenone tetracarboxylic acid, hexahydromellitic acid, benzenepentacarboxylic acid, and mellitic acid.

  In the present invention, a polyol ester of a polycarboxylic acid and a polyol as described above, preferably a diol ester of a dicarboxylic acid and a diol, particularly a (poly) alkylene glycol or polymethylene diol, is also used as the polycarboxylic acid. be able to. Examples of such diol esters include ethylene glycol didipate.

  Furthermore, in the present invention, the polycarboxylic acid may be a polymer carboxylic acid having a plurality of carboxyl groups in the molecule. Examples of such a polymer carboxylic acid include a copolymer of (meth) acrylic acid and (meth) acrylic acid ester.

  In the present invention, the acid anhydride has the general formula (V)

(In the formula, n is an integer of 1 to 3, and R represents a 2n-valent hydrocarbon group.)
It is represented by

  In the present invention, the acid anhydride group means a divalent group in parentheses in the acid anhydride represented by the general formula (V). In the present invention, the hydrocarbon group does not adversely affect the reaction between the acid anhydride and the reactive group of the crosslinkable polymer, and further, is harmful to the battery finally obtained according to the present invention. As long as it does not have a significant influence, it may have an arbitrary substituent. Examples of such a substituent include a halogen atom, a nitro group, an alkoxyl group, and an allyloxy group. In the hydrocarbon group, a part of carbon atoms constituting the hydrocarbon group may be substituted with a hetero atom such as an oxygen atom or a nitrogen atom. Furthermore, according to the present invention, the hydrocarbon group may have a free carboxyl group.

  Among the acid anhydrides represented by the above general formula, as monofunctional acid anhydrides where n is 1, for example, malonic anhydride, succinic anhydride, dodecyl succinic anhydride, maleic anhydride, glutaric anhydride, 2 , 4-Diethylglutaric anhydride, citraconic anhydride, itaconic anhydride, glutaconic anhydride, diglycolic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endocis -Bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic anhydride (trade name Nadic anhydride), methyl-endocis-bicyclo [2.2.1] hept-5-ene-2 , 3-Dicarboxylic acid anhydride (trade name: methyl nadic anhydride), endomethylenetetrahydrophthalic anhydride, methylendomethylene Tiger tetrahydrophthalic anhydride, may be mentioned anhydrous chlorendic acid, phthalic anhydride, nitrophthalic anhydride, diphenic acid, the naphthalic anhydride and the like.

  Among the acid anhydrides represented by the above general formula, as bifunctional acid anhydrides where n is 2, for example, pyromellitic anhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, Examples thereof include ethylene glycol bis (anhydrotrimate), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, and the like. Among the acid anhydrides represented by the above general formula, examples of the trifunctional acid anhydride in which n is 3 include hexahydromellitic anhydride and mellitic anhydride.

  Furthermore, examples of the acid anhydride having a free carboxyl group include β, γ-aconitic anhydride, glycolic anhydride, trimellitic anhydride, polyazeline acid anhydride, and the like.

  Thus, according to the present invention, at least one crosslinking agent selected from a monocarboxylic acid, a polycarboxylic acid and an acid anhydride is reacted with a part of the reactive group of the crosslinkable polymer to thereby form a crosslinkable polymer portion. When the reaction product obtained by partially crosslinking the reaction product, that is, the reactive polymer is immersed in the electrolytic solution, elution and diffusion into the electrolytic solution are suppressed. Therefore, a reactive polymer having such an insoluble fraction of 5 to 80% is supported on a porous film, and an electrode is laminated thereon to form an electrode / reactive polymer-supported porous film laminate, which is a battery. After charging in the container, an electrolytic solution containing an electrolyte containing a cationic polymerization catalyst is injected into the battery container, and the reactive polymer of the electrode / reactive polymer-supported porous film laminate can be brought into contact with the electrolytic solution. For example, in the vicinity of the interface between the porous film and the electrode, a part of the reactive polymer in the electrode / porous film laminate swells in the electrolytic solution or elutes into the electrolytic solution, and the cationic polymerization. A cationic polymerization catalyst in an electrolytic solution, preferably a cationic polymerization with an electrolyte that also serves as a cationic polymerization catalyst, gelling the electrolytic solution, and forming the electrode into a porous film Good adhesion to strongly adhere, thus, the electrode / porous film (i.e., a separator in a battery obtained) can be obtained joined body.

  Furthermore, according to the present invention, as described above, the reactive polymer is partially crosslinked in advance so as to have an insoluble content of 5 to 80%. , Elution and diffusion into the electrolytic solution is prevented or reduced, and it is effectively used for adhesion between the electrode and the porous film. Therefore, by using a relatively small amount of the reactive polymer, the electrode and the porous film Can be stably and more firmly bonded.

  Furthermore, in a porous film carrying a reactive polymer, the reactive polymer is stable in the absence of a cationic polymerization catalyst, and does not react, crosslink, and is stored for a long period of time. But it will not be altered.

  In the present invention, for reacting a crosslinkable polymer with a crosslinking agent and partially supporting the reactive polymer on the substrate porous film, for example, using a solution containing the crosslinkable polymer and the crosslinking agent. The support may be heated on the substrate porous film and then reacted to cause the crosslinkable polymer to react with the crosslinking agent. However, the method is not particularly limited to this method.

  For example, a solution of a crosslinkable polymer may be applied to a porous film and dried, and then the crosslinkable polymer may be contacted with the crosslinkable polymer. Alternatively, the crosslinkable polymer may be reacted with the crosslinker in a solvent. Then, after partially crosslinking to form a reactive polymer, a solution containing this reactive polymer may be applied to a peelable sheet, dried, and then transferred to a porous substrate film.

  In particular, one preferred method according to the present invention is to apply a solution containing both a crosslinkable polymer and a crosslinker to the peelable sheet and dry to form a crosslinkable polymer / crosslinker layer on the peelable sheet. Thereafter, the peelable sheet is superposed on the substrate porous film and heated and pressed to transfer the crosslinkable polymer / crosslinking agent layer to the substrate porous film, and then the crosslinkable polymer / crosslinking agent layer is brought to an appropriate temperature. By heating, a reactive polymer is formed on the porous film.

  Next, a method for producing a battery according to the present invention using the reactive polymer-supported porous film thus obtained will be described.

  First, an electrode is laminated or wound on the reactive polymer-supported porous film to obtain an electrode / reactive polymer-supported porous film laminate, and then this laminate is a battery made of a metal can, a laminate film, or the like. When it is necessary to weld the terminals and weld the terminals, etc., this is performed, and then a predetermined amount of an electrolytic solution in which the cationic polymerization catalyst is dissolved is injected into the battery container, and the electrode / reactive polymer-supported porous material The reactive polymer which a film laminated body has is made to contact with the said electrolyte solution. Next, the battery container is sealed and sealed, and at least a part of the reactive polymer of the reactive polymer-supported porous film is swollen in the electrolyte solution in the vicinity of the interface between the porous film and the electrode, or electrolysis is performed. Elution and diffusion in the liquid, crosslinking by cationic polymerization, gelling at least a part of the electrolyte, and bonding the electrode to the porous film, thus using the porous film as a separator, A strongly bonded battery can be obtained.

  In the present invention, the reactive polymer functions to cause the electrolyte solution to gel at least in the vicinity of the interface between the porous film and the electrode and to bond the electrode and the porous film by crosslinking by cationic polymerization. To do.

  In the present invention, the reactive polymer can be cationically polymerized and crosslinked even at room temperature, although it depends on its structure, the amount supported on the porous film, and the type and amount of the cationic polymerization catalyst. Thus, cationic polymerization can be promoted. In this case, although it depends on the heat resistance and productivity of the material constituting the battery, the heating is usually performed at a temperature of about 40 to 100 ° C. for about 0.5 to 48 hours.

  In addition, in order to swell, elute or diffuse an amount of polymer sufficient to adhere the electrode to the porous film, the electrolyte may be poured into the battery container and then left at room temperature for several hours.

  In the present invention, the electrode / reactive polymer-supported porous film laminate only needs to have an electrode laminated on the reactive polymer-supported porous film. Therefore, depending on the structure and form of the battery, the electrode / reactive polymer Examples of the supported porous film laminate include negative electrode / porous film / positive electrode, negative electrode / porous film / positive electrode / porous film, and the like.

  The electrolytic solution is a solution obtained by dissolving an electrolyte salt in an appropriate solvent. Examples of the electrolyte salt include alkali metals such as hydrogen, lithium, sodium and potassium, alkali metals such as calcium and strontium, tertiary or quaternary ammonium salts, etc. as cation components, hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid A salt containing an anionic component of an inorganic acid such as borohydrofluoric acid, hydrofluoric acid, hexafluorophosphoric acid or perchloric acid, or an organic acid such as carboxylic acid, organic sulfonic acid or fluorine-substituted organic sulfonic acid. it can. Among these, an electrolyte salt containing an alkali metal ion as a cation component is particularly preferably used.

  Specific examples of the electrolyte salt having such an alkali metal ion as a cation component include, for example, alkali perchlorate such as lithium perchlorate, sodium perchlorate, potassium perchlorate, lithium tetrafluoroborate, tetra Alkali metal tetrafluoroborate such as sodium fluoroborate and potassium tetrafluoroborate, alkali metal hexafluorophosphate such as lithium hexafluorophosphate and potassium hexafluorophosphate, alkali metal trifluoroacetate such as lithium trifluoroacetate And alkali metal trifluoromethanesulfonates such as lithium trifluoromethanesulfonate.

  In particular, when obtaining a lithium ion secondary battery according to the present invention, as the electrolyte salt, for example, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, or the like is preferably used.

  Furthermore, any solvent can be used as the solvent for the electrolyte salt used in the present invention as long as it dissolves the electrolyte salt. Examples of the non-aqueous solvent include ethylene carbonate and propylene carbonate. , Cyclic esters such as butylene carbonate and γ-ptyrolactone, ethers such as tetrahydrofuran and dimethoxyethane, and chain esters such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, or a mixture of two or more thereof Can be used as

  Moreover, although the said electrolyte salt is suitably determined according to the kind and quantity of the solvent to be used, normally the quantity used as the density | concentration of 1 to 50 weight% is used in the obtained electrolyte solution.

  In the present invention, an onium salt is preferably used as the cationic polymerization catalyst. Examples of such onium salts include ammonium salts, phosphonium salts, arsonium salts, stibonium salts, iodonium salts, and other cationic components, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, and perchloric acid. An onium salt comprising an anionic component such as a salt can be mentioned.

  However, according to the present invention, among the electrolyte salts described above, in particular, lithium tetrafluoroborate and lithium hexafluorophosphate also function as a cationic polymerization catalyst. Preferably used. In this case, either lithium tetrafluoroborate or lithium hexafluorophosphate may be used alone, or both may be used in combination.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The characteristics of the porous film and the characteristics of the obtained battery were evaluated as follows.

(Thickness of porous film)
It was determined based on a measurement with a 1/10000 mm thickness gauge and a 10,000 times scanning electronic microscopic photograph of the cross section of the porous film.

(Porosity of porous film)
The weight was calculated from the weight W (g) per unit area S (cm ² ) of the porous film, the average thickness t (cm), and the density d (g / cm ³ ) of the resin constituting the porous film by the following equation.

        Porosity (%) = (1− (100 W / S / t / d)) × 100

(Air permeability of porous film)
It calculated | required based on JISP8117.

(Puncture strength)
A piercing test was performed using a compression test kit KES-G5 manufactured by Kato Tech Co., Ltd. The maximum load was read from the load displacement curve obtained by the measurement, and the puncture strength was obtained. A needle having a diameter of 1.0 mm and a radius of curvature of the tip of 0.5 mm was used at a speed of 2 cm / second.

(Gel fraction of porous film)
A porous film cut out in a 10 cm square was folded and sandwiched between 5 cm × 10 cm metal meshes to prepare a 5 cm square sample. The initial weight P ₀ of this sample was measured. Subsequently, this sample was immersed in 100 mL of m-xylene (boiling point 139 ° C.) and then heated to boil xylene for 5 hours. Thereafter, the sample was taken out and dried, and the weight P after the boiling xylene treatment was measured in this way, and the gel fraction R was measured by the following formula from these.

R (%) = (P / P ₀ ) × 100
(Insoluble fraction of reactive polymer)
A reactive polymer layer-carrying porous film carrying a known amount A of a reactive polymer layer was weighed and its weight B was measured. Next, this reactive polymer layer-supported porous film was immersed in a mixed solvent of ethylene carbonate / diethyl carbonate (1/1 volume ratio) at room temperature for 2 hours, then immersed in ethyl methyl carbonate, washed, and air-dried. . Then, the reactive polymer layer carrying porous film processed in this way was weighed, and the weight C was measured. The insoluble fraction of the reactive polymer was calculated by the following formula.

Insoluble fraction (%) = ((A− (BC)) / A) × 100
(Measurement of electrode / separator adhesion)
About each battery obtained by the Example and the comparative example, it decomposed | disassembled before performing a charging / discharging test, and measured the adhesive force between an electrode sheet / separator. That is, the battery is disassembled and the electrode sheet / separator assembly is taken out. Next, the interface of the electrode sheet / separator assembly is peeled off 5 mm from the end, and the end of the electrode sheet and the separator are mutually oriented at 180 °. The load at that time was measured by pulling. This load was divided by the width of the electrode sheet / separator to obtain the adhesive force between the electrode sheet / separator.

(Battery high temperature storage test)
Each battery obtained in Examples and Comparative Examples was fixed to a battery holder, applied with a certain surface pressure, and left in a thermostat at 160 ° C. The positive and negative terminals of the battery were connected to an ohmmeter, and the time when the resistance indicated by the ohmmeter suddenly decreased was measured. The test was up to 60 minutes. After 60 minutes, the battery was taken out of the incubator and allowed to cool, then the battery was disassembled, the area of the separator was measured, and the shrinkage was measured. However, since the separator usually has a larger area than the electrode sheet, the separator protrudes outward from the periphery of the electrode sheet. Therefore, when the battery was disassembled, the shrinkage rate was set to 0% when the area of the separator was equal to the area of the electrode sheet. Therefore, for example, if the area of the separator contracts to 80% of the area of the electrode sheet, the contraction rate of the separator in this case is 20%.

Reference example 1
(Preparation of electrode sheet)
85 parts by weight of lithium cobaltate (Nippon Chemical Industry Co., Ltd., Cellseed C-10) as a positive electrode active material and 10 parts by weight of acetylene black (Denka Black from Denki Kagaku Kogyo Co., Ltd.) as a conductive additive and a binder. 5 parts by weight of vinylidene fluoride resin (KF Polymer L # 1120 manufactured by Kureha Chemical Industry Co., Ltd.) was mixed, and this was made into a slurry using N-methyl-2-pyrrolidone so as to have a solid concentration of 15% by weight. .

  This slurry was applied to an aluminum foil (current collector) having a thickness of 20 μm to a thickness of 200 μm, dried at 80 ° C. for 1 hour, and then at 120 ° C. for 2 hours, and then pressed by a roll press, so that the thickness of the active material layer was A 100 μm positive electrode sheet was prepared.

  In addition, 80 parts by weight of mesocarbon microbeads (MCMB6-28 manufactured by Osaka Gas Chemical Co., Ltd.) as a negative electrode active material, 10 parts by weight of acetylene black (Denka Black manufactured by Denki Kagaku Kogyo Co., Ltd.) as a conductive auxiliary agent, and a binder 10 parts by weight of vinylidene fluoride resin (KF Polymer L # 1120 manufactured by Kureha Chemical Industry Co., Ltd.) is mixed, and this is slurried with N-methyl-2-pyrrolidone so as to have a solid concentration of 15% by weight. It was.

  This slurry was applied to a copper foil (current collector) having a thickness of 20 μm to a thickness of 200 μm, dried at 80 ° C. for 1 hour, dried at 120 ° C. for 2 hours, and then pressed by a roll press to form an active material layer. A negative electrode sheet having a thickness of 100 μm was prepared.

Production Example 1
(Crosslinkable polymer A (3,4-epoxycyclohexylmethyl acrylate monomer component 5 wt%, 3-oxetanyl group-containing monomer component 20 wt%, butyl acrylate monomer component 25 wt% and methyl methacrylate monomer component 50 wt%, weight average molecular weight 317000)
40.0 g of methyl methacrylate, 4.0 g of 3,4-epoxycyclohexylmethyl acrylate, 16.0 g of 3-ethyl-3-oxetanylmethyl methacrylate, 20.0 g of n-butyl acrylate, 10.0 g of ethyl acetate and N, N′- 0.10 g of azobisisobutyronitrile was charged into the polymerization reaction vessel, and while stirring and mixing for 30 minutes while introducing nitrogen gas, the temperature was raised to 70 ° C. When about 2 hours passed, radical polymerization started to progress with an increase in the viscosity of the mixture. As it was, the polymerization reaction was carried out for 5 hours to increase the viscosity to such an extent that stirring was impossible, and then 20.0 g of ethyl acetate was added, and then the polymerization was carried out for 2 hours until stirring was impossible. It was.

  Therefore, 20 g of ethyl acetate was added and polymerization was further performed for 2 hours. Then, 70 g of ethyl acetate was added, stirred, diluted, allowed to stand overnight, allowed to cool, and then N, N′-azobisisobutyro 0.10 g of nitrile and 120 g of ethyl acetate were added, and polymerization was performed at 70 ° C. for 8 hours to obtain a 25 wt% ethyl acetate solution of the crosslinkable polymer A.

  The ethyl acetate solution of the crosslinkable polymer A thus obtained was slightly yellow and viscous and transparent. As a result of molecular weight measurement by GPC, the weight average molecular weight of the crosslinkable polymer A was 317,000, and the number average molecular weight was 98800. Met. The glass transition temperature was 51 ° C.

Production Example 2
(Production of crosslinkable polymer B (3,4-epoxycyclohexylmethyl methacrylate monomer component 5 wt%, 3-oxetanyl group-containing monomer component 20 wt% and methyl methacrylate monomer component 75 wt%))
In a 500 mL three-necked flask equipped with a reflux condenser, 60.0 g of methyl methacrylate, 16.0 g of 3-ethyl-3-oxetanylmethyl methacrylate, 4.0 g of 3,4-epoxycyclohexylmethyl acrylate, 226.6 g of ethylene carbonate Then, 0.15 g of N, N′-azobisisobutyronitrile was charged, mixed with stirring for 30 minutes while introducing nitrogen gas, and then heated to 70 ° C. to carry out radical polymerization for 8 hours. After this, the resulting reaction mixture was cooled to 40 ° C.

  To this reaction mixture, 226.6 g of diethyl carbonate and 0.15 g of N, N′-azobisisobutyronitrile were added, and the mixture was heated again to 70 ° C., and radical polymerization was further performed for 8 hours. Thereafter, the obtained reaction mixture was cooled to 40 ° C. to obtain a mixed solvent solution of 15 wt% crosslinkable polymer B in ethylene carbonate / diethyl carbonate.

  Next, 100 g of this polymer solution was poured into 600 mL of methanol while stirring with a high-speed mixer to precipitate the polymer. The precipitated polymer was separated by filtration, washed several times with methanol, put into a drying tube, dried by circulating dry nitrogen gas (dew point temperature of −150 ° C. or lower) in which liquid nitrogen was vaporized. Then, it was vacuum-dried in a desiccator for 6 hours to obtain a crosslinkable polymer B. The crosslinkable polymer B thus obtained was a pure white powder. As a result of molecular weight measurement by GPC, the weight average molecular weight was 344400 and the number average molecular weight was 174500.

Production Example 3
(Crosslinkable polymer C (3,4-epoxycyclohexylmethyl acrylate monomer component 5% by weight, 3-oxetanyl group-containing monomer component 20% by weight, methyl methacrylate monomer component 50% by weight and n-butyl acrylate monomer component 25% by weight) Manufacturing)
Partially saponified polyvinyl alcohol (polymerization degree 2000, saponification degree 78 mol%) 0.05 g, fully saponified polyvinyl alcohol (polymerization degree 2000, saponification degree 98. 5 to 99.4 mol%) 2.0 g and 210.0 g of ion-exchanged water were charged, and the temperature was raised to 95 ° C. with stirring while introducing nitrogen gas to confirm that the polyvinyl alcohol was completely dissolved. And then cooled to about 30 ° C.

  Thereafter, 40.0 g of methyl methacrylate, 4.0 g of 3,4-epoxycyclohexylmethyl acrylate, 16.0 g of 3-ethyl-3-oxetanylmethyl methacrylate, 20.0 g of n-butyl acrylate, N, N′-azo Charge 0.4 g of bisisobutyronitrile and 6.0 g of 1.0 wt% n-dodecanethiol solution using diethyl carbonate as a solvent, stir and mix for 30 minutes while introducing nitrogen gas, and then heat to 70 ° C. Then, radical suspension polymerization was carried out for 5 hours.

  The reaction mixture thus obtained was filtered and washed with a 500-mesh filter, and then placed in a 500 mL three-necked flask. To this was added 3004 mL of ion-exchanged water, and the mixture was stirred up to 95 ° C. The temperature was raised and hot water washing was performed to remove the remaining polyvinyl alcohol. After filtering and washing with a 500 mesh filter screen, this hot water washing and water washing were repeated again.

  Then, after washing | cleaning with methanol and removing a residual water | moisture content, it vacuum-dried at normal temperature, and the crosslinkable polymer C was obtained. The crosslinkable polymer thus obtained was in the form of white fine particles. As a result of molecular weight measurement by GPC, the weight average molecular weight was 224,000 and the number average molecular weight was 79800.

Production Example 4
(Preparation of porous film A)
Styrene-butadiene block copolymer (JSR Co., Ltd. JSR-TR2601K, styrene content 30 wt%) 5 wt%, modified polyolefin resin (Nippon Polyethylene Co., Ltd. Adtex DH0200, melting point 135 ° C.) 28.5 wt% %, A resin composition consisting of 66.5% by weight of ultra high molecular weight polyethylene having a weight average molecular weight of 2 million and 85 parts by weight of liquid paraffin are uniformly mixed in a slurry state, and at 160 ° C. using a small kneader, Dissolved and kneaded for 60 minutes. Thereafter, the kneaded product was sandwiched between metal plates cooled to 0 ° C. and rapidly cooled to obtain a resin sheet. Subsequently, this resin sheet was heat-pressed at 115 ° C. until the thickness became 0.4 mm, and further press-molded at 20 ° C. while maintaining the above thickness.

  Next, the obtained resin sheet was biaxially stretched 4.0 × 4.0 times in length and width simultaneously at a temperature of 120 ° C. and a speed of 10 mm / second, and then desolvated with heptane to obtain a porous film. It was. This porous film was heat-treated in air at 85 ° C. for 12 hours, and then heat-treated at 126 ° C. for 3 hours to obtain a porous film A. This porous film A had a film thickness of 21 μm, a porosity of 44%, an air permeability of 186 seconds / dL, a puncture strength of 239 gf, and a gel fraction of 12.4%.

Production Example 5
(Preparation of porous film B)
The same styrene-butadiene block copolymer as in Production Example 1 2.5% by weight, high-density polyethylene (melting point 135 ° C.) 29.3% by weight, ultrahigh molecular weight polyethylene having a weight average molecular weight of 2 million 68.2% by weight 15 parts by weight of the resin composition and 85 parts by weight of liquid paraffin were uniformly mixed in a slurry state, and dissolved and kneaded for 60 minutes at 160 ° C. using a small kneader. Thereafter, the kneaded product was sandwiched between metal plates cooled to 0 ° C. and rapidly cooled to obtain a resin sheet. The resin sheet was heat-pressed at 115 ° C. until the thickness became 0.4 mm, and further press-molded at 20 ° C. while maintaining the thickness.

  Next, the obtained resin sheet was biaxially stretched 4.0 × 4.0 times in length and width simultaneously at a temperature of 120 ° C. and a speed of 10 mm / second, and then desolvated with heptane to obtain a porous film. It was. This porous film was heat-treated in air at 85 ° C. for 12 hours, and then heat-treated at 126 ° C. for 3 hours to obtain a porous film B. This porous film B had a film thickness of 19 μm, a porosity of 50%, an air permeability of 167 seconds / dL, a piercing strength of 311 gf, and a gel fraction of 5.3%.

Production Example 6
(Preparation of porous film C)
The same styrene-butadiene block copolymer 5% by weight as in Production Example 1, modified polyolefin resin (Adtex DH0200 manufactured by Nippon Polyethylene Co., Ltd., melting point 135 ° C.) 28.5% by weight, ultra high molecular weight having a weight average molecular weight of 2 million 15 parts by weight of a resin composition composed of 66.5% by weight of polyethylene and 85 parts by weight of liquid paraffin were uniformly mixed in a slurry state, and dissolved and kneaded at 160 ° C. for 60 minutes using a small kneader. Thereafter, the kneaded product was sandwiched between metal plates cooled to 0 ° C. and rapidly cooled to obtain a resin sheet. The resin sheet was heat-pressed at 115 ° C. until the thickness became 0.4 mm, and further press-molded at 20 ° C. while maintaining the thickness.

Next, the obtained resin sheet was biaxially stretched 4.0 × 4.0 times in length and width simultaneously at a temperature of 120 ° C. and a speed of 10 mm / second, and then desolvated with heptane to obtain a porous film. It was. This porous film was heat-treated in air at 85 ° C. for 12 hours, and then heat-treated at 126 ° C. for 1 hour. Furthermore, this porous film was immersed in a benzophenone / methanol solution at a concentration of 0.1% by weight, and then irradiated with ultraviolet rays at a dose of 0.2 J / cm ² to obtain a porous film C. This porous film C had a film thickness of 20 μm, a porosity of 50%, an air permeability of 175 seconds / dL, a puncture strength of 229 gf, and a gel fraction of 62%.

Production Example 7
(Preparation of porous film D)
The same styrene-butadiene block copolymer 10% by weight as in Production Example 1, modified polyolefin resin (Nippon Polyethylene Co., Ltd. Adtex DH0200, melting point 135 ° C.) 27% by weight, ultrahigh molecular weight polyethylene 63 having a weight average molecular weight of 2 million 15 parts by weight of a resin composition comprising 85% by weight and 85 parts by weight of liquid paraffin were uniformly mixed in a slurry state and dissolved and kneaded for 60 minutes at 160 ° C. using a small kneader. Thereafter, the kneaded product was sandwiched between metal plates cooled to 0 ° C. and rapidly cooled to obtain a resin sheet. The resin sheet was heat-pressed at 115 ° C. until the thickness became 0.4 mm, and further press-molded at 20 ° C. while maintaining the thickness.

  Next, the obtained resin sheet was biaxially stretched 4.0 × 4.0 times in length and width simultaneously at a temperature of 120 ° C. and a speed of 10 mm / second, and then desolvated with heptane to obtain a porous film. It was. This porous film was heat-treated in air at 85 ° C. for 12 hours, and then heat-treated at 126 ° C. for 3 hours to obtain a porous film D. This porous film had a film thickness of 23 μm, a porosity of 46%, an air permeability of 275 seconds / dL, a puncture strength of 273 gf, and a gel fraction of 23%.

Production Example 8
(Preparation of porous film X)
15 parts by weight of a resin composition comprising 30.0% by weight of a modified polyolefin resin (Adtex DH0200 manufactured by Nippon Polyethylene Co., Ltd., melting point 135 ° C.), 70.0% by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 2 million, and liquid paraffin 85 parts by weight were uniformly mixed in a slurry state, and melt kneaded for 60 minutes at 160 ° C. using a small kneader. Thereafter, the kneaded product was sandwiched between metal plates cooled to 0 ° C. and rapidly cooled to obtain a resin sheet. The resin sheet was heat-pressed at 115 ° C. until the thickness became 0.4 mm, and further press-molded at 20 ° C. while maintaining the thickness.

  Next, the obtained resin sheet was biaxially stretched 4.0 × 4.0 times in length and width simultaneously at a temperature of 120 ° C. and a speed of 10 mm / second, and then desolvated with heptane to obtain a porous film. It was. This porous film was heat-treated in air at 85 ° C. for 12 hours, and then heat-treated at 126 ° C. for 3 hours to obtain a porous film X. This porous film had a film thickness of 20 μm, a porosity of 41%, an air permeability of 200 seconds / dL, a puncture strength of 225 gf, and a gel fraction of 3%.

Production Example 9
(Preparation of porous film Y)
A slurry of 15 parts by weight of a resin composition comprising 30% by weight of a high-density polyethylene resin (3000B, Mitsui Chemicals Co., Ltd., melting point 135 ° C.) and 70% by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 2 million and 85 parts by weight of liquid paraffin The mixture was uniformly mixed and dissolved and kneaded at 160 ° C. using a small kneader for 60 minutes. Thereafter, the kneaded product was sandwiched between metal plates cooled to 0 ° C. and rapidly cooled to obtain a resin sheet. The resin sheet was heat-pressed at 115 ° C. until the thickness became 0.4 mm, and further press-molded at 20 ° C. while maintaining the thickness.

  Next, the obtained resin sheet was biaxially stretched 4.0 × 4.0 times in length and width simultaneously at a temperature of 120 ° C. and a speed of 10 mm / second, and then desolvated with heptane to obtain a porous film. It was. This porous film was heat-treated in air at 85 ° C. for 12 hours, and then heat-treated at 126 ° C. for 3 hours to obtain a porous film Y. This porous film had a thickness of 20 μm, a porosity of 41%, an air permeability of 200 seconds / dL, a puncture strength of 225 gf, and a gel fraction of 0%.

Production Example 10
The ethyl acetate solution of the crosslinkable polymer A obtained in Production Example 1 was diluted with ethyl acetate to obtain a 10 wt% crosslinkable polymer solution. Separately, an ethyl acetate solution of phthalic anhydride having a concentration of 5% by weight was prepared. While stirring the solution of the crosslinkable polymer A, the phthalic anhydride solution was slowly added dropwise thereto to prepare a mixed solution of the crosslinkable polymer A and phthalic anhydride. The ratio of the number of moles of acid anhydride groups of phthalic anhydride to the number of moles of reactive groups possessed by the crosslinkable polymer was 0.025.

After this mixed solution of the crosslinkable polymer A and phthalic anhydride is applied onto the release paper using a # 8 wire bar, it is heated to 50 ° C. to volatilize ethyl acetate, and thus the crosslinkable polymer is applied onto the release paper. A crosslinkable polymer A / phthalic anhydride layer made of a mixture of A and phthalic anhydride was formed. The release paper was superposed so that the crosslinkable polymer A / phthalic anhydride layer faced the porous film A, passed through a heat roll at 70 ° C., then the release paper was removed, and the crosslinkable polymer was removed on one side. A crosslinkable polymer-supported porous film supported at a coating density of 1.1 g / m ² was obtained.

  Next, this crosslinkable polymer-supported porous film was put into a thermostat at 50 ° C. for 48 hours, the crosslinkable polymer supported on the porous film was reacted with phthalic anhydride, and a part of the crosslinkable polymer was obtained. Crosslinking was thus performed to obtain a reactive polymer-supported porous film 1. In this reactive polymer-supported porous film, the insoluble fraction of the reactive polymer was 40%.

Production Examples 11-13
Reactive polymer-supported films 2 to 4 were produced in the same manner as in Production Example 10 except that porous film B, C or D was used instead of porous film A. In these reactive polymer-supported porous films, the insoluble fraction of the reactive polymer was 40%.

Production Example 14
The crosslinkable polymer B obtained in Production Example 2 was dissolved in ethyl acetate at room temperature to obtain a 10 wt% crosslinkable polymer solution. Separately, an ethyl acetate solution of phthalic anhydride having a concentration of 5% by weight was prepared. While stirring the crosslinkable polymer solution, the phthalic anhydride solution was slowly added dropwise thereto to prepare a mixed solution of the crosslinkable polymer and phthalic anhydride. The ratio of the number of moles of acid anhydride groups of phthalic anhydride to the number of moles of reactive groups possessed by the crosslinkable polymer was 0.025.

After this mixed solution of the crosslinkable polymer B and phthalic anhydride was coated on the release paper using a # 8 wire bar, it was heated to 50 ° C. to volatilize ethyl acetate, and thus the crosslinkable polymer on the release paper. A crosslinkable polymer B / phthalic anhydride layer made of a mixture of B and phthalic anhydride was formed. This release paper was superposed so as to face the crosslinkable polymer B / phthalic anhydride layer porous film A, passed through a hot roll at 70 ° C., then the release paper was removed, and the crosslinkable polymer was removed per side. A crosslinkable polymer-supported porous film supported at a coating density of 1.1 g / m ² was obtained.

  Next, this crosslinkable polymer-supported porous film is put into a thermostat at 50 ° C. for 60 hours, the crosslinkable polymer supported on the porous film is reacted with phthalic anhydride, and a part of the crosslinkable polymer is obtained. Crosslinking was thus performed to obtain a reactive polymer-supported porous film 5. In this reactive polymer-supported porous film, the insoluble fraction of the reactive polymer was 45%.

Production Example 15
The crosslinkable polymer B obtained in Production Example 2 was added to ethyl acetate and stirred and dissolved at room temperature to obtain a solution of the crosslinkable polymer B having a concentration of 10% by weight. Separately, an ethyl acetate solution of propionic acid having a concentration of 10% by weight was prepared. While stirring the solution of the crosslinkable polymer B, the ethyl acetate solution of propionic acid was slowly added dropwise thereto to prepare a mixed solution of the crosslinkable polymer B and propionic acid. The ratio of the number of moles of carboxyl groups of propionic acid to the number of moles of reactive groups possessed by the crosslinkable polymer was 0.85.

After this mixed solution of the crosslinkable polymer B and propionic acid was applied onto the release paper using a # 8 wire bar, it was heated to 50 ° C. to volatilize ethyl acetate, and thus the crosslinkable polymer B was applied onto the release paper. A crosslinkable polymer B / propionic acid layer made of a mixture of propionic acid and propionic acid was formed. The release paper was superposed so that the crosslinkable polymer B / propionic acid layer faced the porous film A, passed through a hot roll at 70 ° C., then the release paper was removed, and the crosslinkable polymer was removed per side. A crosslinkable polymer-supported porous film supported at a coating density of 1.1 g / m ² was obtained.

  Next, the crosslinkable polymer-supported porous film is put into a thermostat at 50 ° C. for 96 hours, the crosslinkable polymer supported on the porous film is reacted with propionic acid, and a part of the crosslinkable polymer is crosslinked. Thus, a reactive polymer-supported porous film 6 was obtained. In this reactive polymer-supported porous film, the insoluble fraction of the reactive polymer was 43%.

Production Example 16
A crosslinkable polymer-supported porous film 7 was obtained in the same manner as in Production Example 15 except that the porous film B was used in place of the porous film A. In this reactive polymer-supported porous film, the insoluble fraction of the reactive polymer was 43%.

Production Example 17
Crosslinkable polymer B was added to ethyl acetate and stirred and dissolved at room temperature to obtain a 10% strength by weight solution of crosslinkable polymer B. Separately, an ethanolic solution of adipic acid having a concentration of 10% by weight was prepared. While stirring the solution of the crosslinkable polymer B, the adipic acid solution was slowly added dropwise thereto to prepare a mixed solution of the crosslinkable polymer B and adipic acid. The ratio of the number of moles of carboxyl groups of adipic acid to the number of moles of reactive groups possessed by the crosslinkable polymer was 0.5.

After this mixed solution of the crosslinkable polymer B and adipic acid was applied onto the release paper using a # 8 wire bar, it was heated at 50 ° C. to volatilize ethyl acetate, and thus the crosslinkable polymer on the release paper. A crosslinkable polymer B / adipic acid layer composed of a mixture of B and adipic acid was formed. The release paper was superposed so that the crosslinkable polymer B / adipic acid layer faced the porous film A, passed through a hot roll at 70 ° C., then the release paper was removed, and the crosslinkable polymer was removed per side. A crosslinkable polymer-supported porous film supported at a coating density of 1.1 g / m ² was obtained.

  Next, the crosslinkable polymer-supported porous film is put into a thermostat at 50 ° C. for 48 hours, the crosslinkable polymer supported on the porous film is reacted with adipic acid, and a part of the crosslinkable polymer is crosslinked. Thus, a reactive polymer-supported porous film 8 was obtained. In this reactive polymer-supported porous film, the insoluble content of the reactive polymer was 19%.

Production Example 18
A crosslinkable polymer-supported porous film 9 was obtained in the same manner as in Production Example 17 except that the porous film B was used in place of the porous film A. In this reactive polymer-supported porous film 7, the insoluble content of the reactive polymer was 19%.

Production Example 19
The crosslinkable polymer C obtained in Production Example 3 was added to ethyl acetate and stirred and dissolved at room temperature to obtain an ethyl acetate solution of a 10 wt% crosslinkable polymer solution C. Separately, an ethyl acetate solution of propionic acid having a concentration of 10% by weight was prepared. While stirring the solution of the crosslinkable polymer C, the ethyl acetate solution of propionic acid was slowly added dropwise thereto to prepare a mixed solution of the crosslinkable polymer C and propionic acid. The ratio of the number of moles of carboxyl groups of propionic acid to the number of moles of reactive groups possessed by the crosslinkable polymer was 0.17.

After applying the mixed solution of the crosslinkable polymer and propionic acid onto the release paper using a # 7 wire bar, the mixture was heated to 50 ° C. to volatilize the ethyl acetate used as the solvent, and crosslinkable on the release paper. A polymer C / propionic acid layer was formed. Such a release paper was superposed on both sides of the crosslinkable polymer C / propionic acid layer so as to face the porous film A, passed through a hot roll at 70 ° C., then the release paper was removed, A crosslinkable polymer-supported porous film obtained by supporting a polymer at a coating amount of 1.9 g / m ² was obtained.

  Next, the crosslinkable polymer-supported porous film is put into a thermostat at 50 ° C. for 96 hours, the crosslinkable polymer supported on the porous film is reacted with propionic acid, and a part of the crosslinkable polymer is crosslinked. Thus, a reactive polymer-supported porous film 10 was obtained. In this reactive polymer-supported porous film, the insoluble content of the reactive polymer was 35%.

Production Example 20
Production Example 17 except that the crosslinkable polymer C was used in place of the crosslinkable polymer B, and the ratio of the number of moles of carboxyl groups of adipic acid to the number of moles of reactive groups of the crosslinkable polymer was 1.0. In the same manner as described above, a reactive polymer-supported porous film 11 was obtained. In this reactive polymer-supported porous film 11, the insoluble content of the reactive polymer was 80%.

Production Examples 21 and 22
Reactive polymer-supported porous films 12 and 13 were obtained in the same manner as in Production Example 10 except that porous film X or Y was used in place of porous film A. In these reactive polymer-supported porous films, the insoluble fraction of the reactive polymer was 40%.

Production Example 23
A reactive polymer-supported porous film 14 was obtained in the same manner as in Production Example 15 except that the porous film X was used in place of the porous film A. In this reactive polymer-supported porous film, the insoluble fraction of the reactive polymer was 43%.

Production Example 24
A reactive polymer-supported porous film 15 was obtained in the same manner as in Production Example 19 except that the porous film X was used instead of the porous film A. In this reactive polymer-supported porous film, the insoluble content of the reactive polymer was 35%.

Examples 1-11
Each of the reactive polymer-supported porous films 1 to 11 obtained in Production Examples 10 to 20 was sandwiched between the positive electrode and the negative electrode obtained in Reference Example 1, and further pressed at 80 ° C. by hot pressing. The size of the reactive polymer-supported porous film was such that the portion protruding from the electrode was 1 mm.

  Each of the electrode / separator laminates thus obtained was charged into an aluminum laminate package, and then an electrolyte was injected into the package. This electrolytic solution is composed of a mixed solvent of ethylene carbonate / diethyl carbonate (capacity ratio 1: 1) in which lithium hexafluorophosphate is dissolved at a concentration of 1.0 mol / L. After injecting the electrolyte into the laminate package, the laminate package is sealed, left at room temperature for 12 hours, and then heated at 50 ° C. for 24 hours to cationically polymerize the reactive groups of the reactive polymer, thereby reacting the electrode. A polymer layer was adhered, thus producing a battery having an electrode / separator assembly. Table 1 shows the electrode / separator adhesive strength of these batteries and the results of the high-temperature storage test of these batteries.

  The reactive polymer-supported porous film according to the present invention provides an electrode / separator assembly having high adhesive force therebetween, and the obtained battery has excellent high-temperature storage stability, the separator does not shrink, and the short-circuit time is short. Also short.

Comparative Examples 1-4
In place of the reactive polymer-supported porous films 1 to 11 obtained in Production Examples 10 to 20, respectively, except that the reactive polymer-supported porous films 12 to 15 obtained in Production Examples 22 to 25 were used, respectively. A battery was fabricated in the same manner as in the above example. Table 2 shows the electrode / separator adhesive strength of these batteries and the results of the high-temperature storage test of these batteries.

  Any of the obtained batteries has a high adhesive force with respect to the electrode / separator assembly, but the short circuit time is short.

Comparative Examples 5-8
A battery was produced in the same manner as in the above example except that the porous film A, C, X or Y was used in place of the battery separator obtained in Production Examples 11 to 21, respectively. Table 3 shows the electrode / separator adhesion in these batteries and the results of the high-temperature storage test of these batteries.

  In each of the batteries obtained, there is no adhesion between the electrode and the separator, and in addition, the high temperature storage stability is poor, the separator is significantly contracted, and the short circuit time is short.

Claims (5)

  A reactive polymer-supported porous film for a battery separator comprising a reactive polymer supported on a porous film, wherein the porous film contains a polyolefin and a styrene-butadiene copolymer. A cross-linkable polymer having a plurality of reactive groups selected from a 3-oxetanyl group and an epoxy group in the molecule depending on a part of the reactive groups. A separator for a battery, characterized in that the reactive polymer is formed from a cross-linked polymer obtained by reacting with at least one cross-linking agent selected from acid anhydrides, polycarboxylic acids and monocarboxylic acids and partially cross-linking. Reactive polymer-supported porous film for.   The cross-linkable polymer is a radical copolymer of at least one radical polymerizable monomer selected from a radical polymerizable monomer having a 3-oxetanyl group and a radical polymerizable monomer having an epoxy group and another radical polymerizable monomer. A reactive polymer-supported porous film for the battery separator according to claim 1.   The reactive polymer-supported porous film for battery separator according to claim 1 or 2, wherein the reactive polymer has an insoluble fraction of 5% or more.   An electrode is laminated on the reactive polymer-supported porous film according to claim 1 to obtain an electrode / reactive polymer-supported porous film laminate, and the electrode / reactive polymer-supported porous film laminate. After charging the body into the battery container, an electrolytic solution containing a cationic polymerizable catalyst is injected into the battery container, and the reactive polymer of the electrode / reactive polymer-supported porous film laminate is brought into contact with the electrolytic solution. An electrode / separator assembly obtained by cationic polymerization of the reactive polymer. A battery comprising the electrode / separator assembly according to claim 4.