JP2007042592A - Solid electrolyte film and its manufacturing method, equipment, electrode membrane assembly, and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continuously manufacture a film having a constant quality and superior mechanical strength and high ion conductivity by making a solid electrolyte into a film continuously. <P>SOLUTION: A dope 24 containing a solid electrolyte is made to flow and cast on a casting band 82 and a cast film 24a is formed. After the cast film 24a is separated from the casting band 82 and made into a film 62, it is sent to a tenter 64, and by holding the both end parts by a clip 64a and transferring, the film 62 is extended in width direction and dried by supplying drying air from an air feeding duct 64b. Furthermore, the film 62 is dried in a drying chamber 69 and a solid electrolyte film is obtained. Since this solid electrolyte film is extended in width direction by the tenter 64 and its orientation is improved, it is superior in mechanical strength. By this method, the solid electrolyte film having superior mechanical strength and high proton conductivity can be manufactured with a constant quality in large volume continuously. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid electrolyte film, a method for producing the same, equipment, an electrode membrane composite using the solid electrolyte film, and a fuel cell. In particular, the present invention relates to a solid electrolyte film having proton conductivity and used in a fuel cell, and The present invention relates to a manufacturing method, equipment, an electrode membrane composite using a solid electrolyte film, and a fuel cell.

  In recent years, lithium ion batteries and fuel cells that can be used as a power source for portable devices and the like have been actively researched, and active research has also been conducted on solid electrolytes that are members thereof. The solid electrolyte is, for example, a lithium ion conductive material or a proton conductive material.

  Generally, there are film-like proton conductive materials, and a film-like solid electrolyte for use as a solid electrolyte layer of a battery such as a fuel cell and a method for producing the same have been proposed. For example, Patent Document 1 proposes a method of immersing a polyvinylidene fluoride resin in a liquid for mixing an electrolyte and a plasticizer. Patent Document 2 proposes a method for producing a proton conductive membrane by synthesizing an inorganic compound in a solution containing an aromatic polymer material having a sulfonic acid group and removing the solvent. . In this method, silicon oxide, phosphoric acid derivatives and the like are added to improve pores. In Patent Document 3, a method for producing an ion exchange membrane by adding a metal oxide precursor to a solution containing an ion exchange resin, casting a liquid obtained by subjecting the precursor to hydrolysis and polycondensation reaction, and the like. Has been proposed. In Patent Document 4, a polymer film having proton conductivity is produced by a solution casting method, that is, a solution casting method, and this film is immersed in an organic compound aqueous solution that is soluble in water and has a boiling point of 100 ° C. or higher. Thus, a method of producing a proton conducting membrane by causing equilibrium swelling and evaporating water by heating has been proposed. In Patent Document 5, a method of obtaining a solid electrolyte membrane by dissolving a compound mainly composed of polybenzimidazole having an anionic ionic group in an alcohol solvent having a boiling point of 90 ° C. or higher containing tetraalkylammonium hydroxide. Has been proposed.

  However, in Patent Document 1, the melt film-forming method is denied, and the problem that impurities contained in the raw material remain in the film is not solved in the manufacturing method. In addition, all the methods of Patent Documents 2 to 5 are manufacturing methods on a small scale, and are not considered methods for mass production.

By the way, as a method for forming a polymer into a film, there are a melt film forming method and a solution film forming method as well known. The former can produce a film without using a solvent, but there is a problem that the polymer is modified by heating or impurities in the raw material polymer remain in the film as they are. On the other hand, although the latter has problems in equipment such as solution production equipment and solvent recovery equipment, the temperature during heating may be low, and it is possible to remove impurities in the polymer in the solution production process. There is. Furthermore, the latter also has an advantage that a film excellent in flatness and smoothness can be produced as compared with the former film. Therefore, in Patent Document 6, as a manufacturing method for realizing continuous film formation, hydrolysis treatment is performed while bringing a melted solid electrolyte film into contact with a reaction liquid and transporting it while gripping both side ends of the solid electrolyte film. A method of performing is proposed.
JP-A-9-320617 JP 2001-307752 A JP 2002-231270 A JP 2004-079378 A JP 2004-131530 A JP 2004-0667804 A

  According to the production method of Patent Document 6, in order to stretch the film in the width direction while gripping and transporting both side edges of the film after being brought into contact with the reaction liquid, drying is performed while suppressing the occurrence of wrinkles and sagging. The solid electrolyte film can be continuously mass-produced. However, it cannot be expected to produce a film that sufficiently satisfies mechanical strength such as durability required for a solid electrolyte film used for a heat source of a domestic water supply or a fuel cell. Further, Patent Document 4 describes that various solid electrolyte films can be produced by a solution casting method, but there is no description of a specific production method.

  The present invention aims to solve the above problems, and has a solid electrolyte film with improved mechanical strength such as high ion conductivity, excellent flatness without wrinkles and sagging, and excellent durability. Provided is a production method which can be produced continuously and in large quantities with a constant quality.

  Therefore, a method for producing a solid electrolyte film according to the present invention includes a casting film forming step of casting a dope containing a solid electrolyte and an organic solvent from a casting die on a support to form a casting film, It has a stripping process for stripping the cast film as a film from the support, and a drying process for drying the film to form a solid electrolyte film. After the film is gripped, the film is stretched in the width direction while being conveyed by the movement of the gripping means, and the film is dried and dried by the drying means.

  It is preferable to blow dry air on the film by a drying means having an air outlet. It is preferable to keep the temperature of the drying air substantially constant while changing the distance in the width direction of the film by changing the distance between the gripping means opposed to each other at both ends of the film.

  When the length between the gripping positions of the gripping means when the film is gripped by the gripping means is defined as a gripping width, a first step for holding the gripping width constant, a second step for widening the gripping width, and a gripping width It is preferable to have a third step for reducing the width and a fourth step for keeping the grip width constant after the third step.

  The grip width in the first step is A (mm), the maximum grip width in the second step is B (mm), and after the grip width is reduced in the third step, the film is removed from the gripping means. When the width of the film is C (mm), it is preferable that A, B, and C satisfy the condition of 1 <100 × (BC) / A <15.

  The organic solvent is preferably a mixture of a poor solvent and a good solvent for the solid electrolyte. The weight ratio of the poor solvent in the organic solvent is preferably 10% or more and less than 100%. The good solvent preferably contains dimethyl sulfoxide, and the poor solvent preferably contains an alcohol having 1 to 5 carbon atoms.

ただし、ＸはＨ、ＹはＳＯ_２ 、Ｚは化４の（Ｉ）または（ＩＩ）に示す構造であり、ｎとｍとは０．１≦ｎ／（ｍ＋ｎ）≦０．５を満たす。

The solid electrolyte is preferably a hydrocarbon polymer. The hydrocarbon polymer is preferably an aromatic polymer having a sulfonic acid group. The aromatic polymer is preferably a copolymer composed of structural units represented by general formulas (I) to (III) of Chemical Formula 3.

However, X is H, Y is SO ₂ , Z is a structure shown in Chemical Formula (I) or (II), and n and m satisfy 0.1 ≦ n / (m + n) ≦ 0.5.

  The production facility for a solid electrolyte film of the present invention includes a casting film forming apparatus for casting a dope containing a solid electrolyte and an organic solvent from a casting die on a support, and a casting film, and a casting film. A peeling device that peels the film as a film from the support, and a drying device that dries the film to form a solid electrolyte film. The drying device moves along the film conveyance path and grips both side edges of the film. After that, it is preferable to include a drying / stretching / drying apparatus including a gripping unit that stretches the film in the width direction and a drying unit that dries the film while moving along the conveyance path.

  The solid electrolyte film of the present invention is manufactured by any one of the above manufacturing methods.

  The electrode membrane composite of the present invention is provided with the above solid electrolyte film and an anode electrode that is provided in close contact with one surface of the solid electrolyte film and generates protons from a hydrogen-containing substance supplied from the outside. And a cathode electrode that is provided in close contact with the other surface of the solid electrolyte film and synthesizes water composed of protons that have passed through the solid electrolyte film and gas supplied from the outside.

  Furthermore, the present invention comprises the above electrode membrane composite, and a current collector provided in contact with the electrode of the electrode membrane composite and for transferring electrons to and from the anode and cathode electrodes. The fuel cell includes the characteristic fuel cell.

  According to the present invention, a solid electrolyte film having improved mechanical strength such as high ion conductivity and excellent durability as compared with the conventional one can be produced continuously and in large quantities with a constant quality. And the electrode membrane assembly using this solid electrolyte film expresses an excellent electromotive force when used in a fuel cell.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described here. First, the solid electrolyte film of the present invention will be described, and then the method for producing the film will be described.

[material]
In the present invention, a polymer having a proton donating group is used as a solid electrolyte to be formed into a film by the production method described later. The polymer having a proton donating group is not particularly limited, and a polymer having an acid residue and known as a proton conducting material can be used. Among them, preferred polymers are those having an acid residue, for example, an addition polymerization polymer compound having a sulfonic acid in the side chain, a sulfonated poly (meth) acrylate having a side chain phosphate group, and a polyether ether ketone. Examples include polyether ether ketone, sulfonated polybenzimidazole, sulfonated polysulfone obtained by sulfonated polysulfone, and sulfonated products of heat-resistant aromatic polymer compounds. Examples of the addition polymerization polymer compound having a sulfonic acid in the side chain include perfluorosulfonic acid represented by Nafion (registered trademark), sulfonated styrene, sulfonated polyacrylonitrile styrene, sulfonated polyacrylonitrile butadiene styrene, and the like. Examples of the sulfonated product of the heat resistant aromatic polymer include sulfonated polyimide.

  Preferable examples of perfluorosulfonic acid include substances described in, for example, JP-A-4-366137, JP-A-6-231777, and JP-A-6-342665. Is particularly preferred. However, in Chemical formula 5, m is 100 to 10000, 200 to 5000 is preferable, and 500 to 2000 is more preferable. And n is 0.5-100, and 5-13.5 is especially preferable. X is substantially equivalent to m, and y is substantially equivalent to n.

  Preferred examples of the sulfonated styrene, the sulfonated polyacrylonitrile styrene, and the sulfonated polyacrylonitrile butadiene styrene include the compounds described in JP-A-5-174856 and JP-A-6-1111834, and the substances shown in Chemical formula 6. Can be mentioned.

  Examples of the sulfonated product of the heat-resistant aromatic polymer include, for example, JP-A-6-49302, JP-A-2004-10777, JP-A-2004-345997, JP-A-2005-15541, JP-A-2005-15541. JP 2002-110174 A, JP 2003-100317 A, JP 2003-55457 A, JP 9345818 A, JP 2003-257451 A, JP 2000-510511 A, JP 2002-105200 A. Substances described in the gazettes are mentioned, and among them, the substances shown in Chemical Formula 3 and Chemical Formulas 7 and 8 below are particularly preferable.

  In particular, the film of the substance shown in Chemical Formula 3 achieves both the hygroscopic expansion coefficient and the proton conductivity. When n / (m + n) <0.1, there are too few sulfonic acid groups, and proton conduction paths, so-called proton channels may not be sufficiently formed. Therefore, the obtained film may not exhibit proton conductivity sufficient for practical use. In addition, when n / (m + n)> 0.5, the water absorbability of the film becomes high, so that the expansion coefficient due to water absorption, that is, the water absorption expansion coefficient increases, and the film is likely to deteriorate.

  The sulfonation reaction in the process of obtaining the above compound can be performed according to various synthetic methods in known literature. As the sulfonating agent, sulfuric acid (concentrated sulfuric acid), fuming sulfuric acid, gaseous or liquid sulfur trisulfide, sulfur trisulfide complex, amidosulfuric acid, chlorosulfonic acid and the like can be used. As the solvent, hydrocarbons (benzene, toluene, nitrobenzene, chlorobenzene, dioxetane, etc.), alkyl halides (methylene chloride, chloroform, dichloroethane, carbon tetrachloride, etc.) and the like can be used. The reaction temperature may be determined in the range of −20 ° C. to 200 ° C. according to the activity of the sulfonating agent. As another method, a mercapto group, a disulfide group, and a sulfinic acid group can be introduced into the monomer in advance, and a sulfonated product can be synthesized by an oxidation reaction with an oxidizing agent. At this time, hydrogen peroxide, nitric acid, bromine water, hypochlorite, hypobromite, potassium permanganate, chromic acid, etc. can be used as the oxidizing agent, and water, acetic acid, Propionic acid or the like can be used. The reaction temperature in this method may be determined in the range of room temperature (for example, 25 ° C.) to 200 ° C. according to the activity of the oxidizing agent. As yet another method, a sulfonated compound may be synthesized by introducing a halogenoalkyl group into the monomer in advance and performing a substitution reaction with sulfite, bisulfite, or the like. In this case, water, alcohols, amides, sulfoxides, sulfones and the like can be used as the solvent. The reaction temperature may be determined in the range of room temperature (for example, 25 ° C.) to 200 ° C. In addition, the solvent in the above sulfonation reaction may be a mixture in which two or more kinds of substances are mixed.

In the reaction step to the sulfonated product, an alkyl sulfonating agent may be used. As a general method, there is a Friedel-Crafts reaction using sultone and AlCl ₃ (Journal of Applied Polymer Science, Vol. 36, 1753-1767, 1988). When an alkyl sulfonating agent is used to perform the Friedel-Crafts reaction, hydrocarbons (benzene, toluene, nitrobenzene, acetophenone, chlorobenzene, trichlorobenzene, etc.), alkyl halides (methylene chloride, chloroform, dichloroethane, Carbon chloride, trichloroethane, dichloroethane, tetrachloroethane, etc.) can be used. The reaction temperature may be determined in the range of room temperature to 200 ° C. Note that the solvent in the reaction may be a mixture of two or more substances.

  In the case of producing a solid electrolyte film having the structure of Chemical Formula 3, a dope containing a polymer (hereinafter referred to as a precursor) in which X of Chemical Formula 3 is a cation species other than a hydrogen atom is prepared, and this is used as a support. A polymer having the structure of Chemical Formula 3 by casting on the film and peeling off as a film containing a precursor (hereinafter referred to as a precursor film), and then substituting the precursor film with protons to set X to H A solid electrolyte film made of can be produced.

  The cationic species means an atom or atomic group that generates a cation when ionized. This cationic species need not be monovalent. As cations other than hydrogen atoms, alkali metal cations, alkaline earth metal cations, and ammonium cations are preferable, and calcium ions, barium ions, quaternary ammonium ions, lithium ions, sodium ions, and potassium ions are more preferable. In addition, even if a film is produced by leaving X in Chemical Formula 3 as a cationic species without using H, the film has a function as a solid electrolyte. However, the proton conductivity increases as the proportion of the cation species of X substituted by H increases. In that sense, X is particularly preferably H.

As solid electrolyte, what has the following various performance is preferable. The ionic conductivity is preferably 0.005 S / cm or more, and more preferably 0.01 S / cm or more, for example, at 25 ° C. and a relative humidity of 70%. Further, the ionic conductivity after being immersed in a 50% aqueous methanol solution at 18 ° C. for one day is preferably 0.003 S / cm or more, more preferably 0.008 S / cm or more, and particularly with respect to before immersion. What the fall rate of the ionic conductivity after immersion is 20% or less is preferable. The methanol diffusion coefficient is preferably 4 × 10 ⁻⁷ cm ² / s or less, and particularly preferably 2 × 10 ⁻⁷ cm ² / s or less.

  As for strength, those having an elastic modulus of 10 MPa or more are preferred, and those having a modulus of 20 MPa or more are particularly preferred. The method for measuring the elastic modulus is described in detail in paragraph [0138] of JP-A-2005-104148, and the above value of the elastic modulus is a value obtained by a tensile tester manufactured by Toyo Baldwin. Therefore, when obtaining the elastic modulus using another test method or tester, it is preferable to obtain the correlation with the value obtained by the test method or tester in advance.

  Regarding durability, before and after the time-lapse test immersed in 50% methanol at a constant temperature, each change rate of weight, ion exchange capacity, and methanol diffusion coefficient is preferably 20% or less, preferably 15% or less. Some are particularly preferred. Further, before and after the time-lapse test in hydrogen peroxide, the rate of change in weight, ion exchange capacity, and methanol diffusion coefficient is preferably 20% or less, and particularly preferably 10% or less. Further, in 50% methanol, the volume swelling rate at a constant temperature is preferably 10% or less, and particularly preferably 5% or less.

  Further, those having a stable water absorption and water content are preferred. Moreover, it is preferable that it is so small that solubility is substantially negligible with respect to alcohols, water, and a mixed solvent of alcohol and water. Further, it is preferable that the weight loss and the shape change when immersed in the liquid are small enough to be substantially ignored.

  The ionic conduction performance of the solid electrolyte film is expressed by a so-called index which is a ratio between the ionic conductivity and the methanol permeability coefficient. And it can be said that the larger the index in a certain direction, the higher the ion conduction performance in that direction. In the thickness direction of the solid electrolyte film, the ionic conductivity is proportional to the thickness, and the methanol permeability coefficient is inversely proportional to the thickness. Therefore, the ionic conductivity of the solid electrolyte film can be controlled by changing the thickness. In a solid electrolyte film used for a fuel cell, an anode electrode is provided on one side and a cathode electrode is provided on the other side. Therefore, the index in the thickness direction of the solid electrolyte film is larger than the index in the other direction. Is preferred. The thickness of the solid electrolyte film is preferably 10 to 300 μm. For example, in the case of a solid electrolyte having both high ionic conductivity and methanol diffusion coefficient, it is particularly preferable to produce a film having a thickness of 50 to 200 μm, and a solid having both low ionic conductivity and methanol diffusion coefficient. In the case of an electrolyte, it is particularly preferable to produce a film so that the thickness is 20 to 100 μm.

  The heat resistant temperature is preferably 200 ° C. or higher, more preferably 250 ° C. or higher, and particularly preferably 300 ° C. or higher. The heat-resistant temperature here means a temperature that reaches 5% weight loss when heated at a rate of 1 ° C./min. Note that this weight reduction is calculated excluding the amount of evaporation such as moisture.

Furthermore, when a solid electrolyte is used as a film for a fuel cell, the solid electrolyte is preferably a solid electrolyte having a maximum output density of 10 mW / cm ² or more.

  By using the above solid electrolyte, it is possible to produce a solution suitable for production of a film, and it is possible to produce a solid electrolyte film suitable for a fuel cell. The solution suitable for the production of the film is, for example, a solution having a relatively low viscosity and easily removing foreign matters in advance by filtration. In the following description, the obtained solution is referred to as a dope.

  The organic solvent used for the dope (sometimes simply referred to as a solvent) may be any organic compound that can dissolve the polymer as the solid electrolyte. Examples include aromatic hydrocarbons (eg, benzene, toluene, etc.), halogenated hydrocarbons (eg, dichloromethane, chlorobenzene, etc.), alcohols (eg, methanol, ethanol, n-propanol, n-butanol, diethylene glycol, etc.), Ketones (eg, acetone, methyl ethyl ketone, etc.), esters (eg, methyl acetate, ethyl acetate, propyl acetate, etc.), ethers (eg, tetrahydrofuran, methyl cellosolve, etc.), and nitrogen-containing compounds (N-methylpyrrolidone (NMP)) N, N-dimethylformamide (DMF), N, N′-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO) and the like.

  The dope solvent may be a mixture of a plurality of substances. When making a solvent into a mixture, it is preferable to set it as the mixture of the good solvent of a solid electrolyte, and a poor solvent. In the case of producing a solid electrolyte film having the structure of Chemical Formula 3, when protonation is carried out in the film production process, a mixture of a precursor good solvent and a poor solvent may be used as a solvent. Mix the solvent and solid electrolyte so that the solid electrolyte is 5% by weight of the total weight, and determine whether the solvent used is a poor solvent or a good solvent based on the presence or absence of insoluble matter. can do. A good solvent for the solid electrolyte, that is, a substance that dissolves the solid electrolyte has a relatively high boiling point among the compounds generally used as the solvent, while the poor solvent has a boiling point among the compounds generally used as the solvent. Is the relatively low one. Therefore, by mixing the poor solvent with the good solvent, the efficiency and effect of removing the solvent in the film production process can be enhanced, and in particular, the drying efficiency of the cast film can be greatly improved.

  In a mixture of a good solvent and a poor solvent, the weight ratio of the poor solvent is preferably as large as possible, specifically 10% or more and less than 100%. More preferably, (weight of good solvent) :( weight of poor solvent) is 90:10 to 10:90. Thereby, since the ratio of the low boiling-point component in the weight of all the solvents becomes large, the drying efficiency and the drying effect in the manufacturing process of a solid electrolyte film can be improved more.

  As the good solvent component, DMF, DMAc, DMSO, and NMP are preferable. Among them, DMSO is particularly preferable in terms of safety and relatively low boiling point. As the poor solvent component, a so-called lower alcohol having 1 to 5 carbon atoms, methyl acetate, and acetone are preferable. Among them, a lower alcohol having 1 to 3 carbon atoms is more preferable, and when DMSO is used as a good solvent. Methyl alcohol is particularly preferred from the viewpoint of the most excellent compatibility with it.

  In order to improve various film characteristics when the solid electrolyte is used as a film, an additive can be added to the dope. Examples of the additive include an antioxidant, fibers, fine particles, a water absorbing agent, a plasticizer, and a compatibilizer. The addition rate of these additives is preferably in the range of 1% by weight to 30% by weight when the total solid content in the dope is 100% by weight. However, the addition rate and the type of substance do not adversely affect the ionic conductivity. The additive will be specifically described below.

  Antioxidants include (hindered) phenolic, monovalent or divalent sulfur, trivalent phosphorus, benzophenone, benzotriazole, hindered amine, cyanoacrylate, salicylate, oxalic acid anilide These compounds are listed as preferred examples. Specific examples thereof include compounds described in JP-A-8-53614, JP-A-10-101873, JP-A-11-114430, and JP-A-2003-151346.

  Preferred examples of the fibers include perfluorocarbon fibers, cellulose fibers, glass fibers, polyethylene fibers and the like, and specifically, JP-A-10-31815, JP-A-2000-231938, JP-A-2001-307545. Examples thereof include fibers described in JP-A-2003-317748, JP-A-2004-63430, and JP-A-2004-107461.

  Examples of the fine particles include titanium oxide and zirconium oxide, and specific examples include various fine particles described in JP-A Nos. 2003-178777 and 2004-217931.

  Water-absorbing agents, that is, hydrophilic substances include cross-linked polyacrylate, starch-acrylate, poval, polyacrylonitrile, carboxymethylcellulose, polyvinylpyrrolidone, polyglycol dialkyl ether, polyglycol dialkyl ester, synthetic zeolite, titania gel, zirconia gel And yttria gel are preferable examples, and specific examples thereof include water absorbing agents described in JP-A-7-135033, JP-A-8-20716, and JP-A-9351857.

  Preferred examples of the plasticizer include phosphate ester compounds, chlorinated paraffins, alkylnaphthalene compounds, sulfone alkylamide compounds, oligoethers, and aromatic nitriles. And plasticizers described in JP-A-2003-317539.

  As the compatibilizer, those having a boiling point or sublimation point of 250 ° C. or higher are preferable, and those having a boiling point or 300 ° C. or higher are more preferable.

  The dope may further contain various polymers for the purpose of (1) increasing the mechanical strength of the film and (2) increasing the acid concentration in the film.

  Among the above objects, a polymer having a molecular weight of about 10,000 to 1,000,000 and having a good compatibility with the solid electrolyte is suitable for (1). For example, perfluorinated polymers, polystyrene, polyethylene glycol, polyoxetane, polyether ketone, polyether sulfone, and polymers containing two or more polymer repeating units are preferred. Moreover, it is preferable to contain these substances in a dope so that it may become the range of 1 to 30 weight% with respect to the total weight when it is set as a film. The compatibility with the solid electrolyte may be improved by using a compatibilizer. As the compatibilizer, those having a boiling point or sublimation point of 250 ° C. or higher are preferable, and those having a boiling point of 300 ° C. or higher are more preferable.

  Among the above objects, (2) is preferably a polymer having a proton acid site. Examples of such a polymer include perfluorosulfonic acid polymers such as Nafion (registered trademark), sulfonated polyetheretherketone having a phosphate group in the side chain, sulfonated polyethersulfone, sulfonated polysulfone, and sulfonated polybenzimidazole. Examples thereof include sulfonated products of heat-resistant aromatic polymer compounds such as Moreover, it is preferable to contain these substances in a dope so that it may become the range of 1 to 30 weight% with respect to the total weight when it is set as a film.

  Further, when the obtained solid electrolyte film is used in a fuel cell, an active metal catalyst that promotes the oxidation-reduction reaction between the anode fuel and the cathode fuel may be added to the dope. As a result, the fuel that has permeated into the solid electrolyte film from one electrode is consumed in the solid electrolyte without reaching the other electrode, so that the crossover phenomenon can be prevented. The active metal catalyst is not particularly limited as long as it functions as an electrode catalyst, but platinum or an alloy based on platinum is particularly suitable.

[Dope production]
FIG. 1 shows a dope manufacturing facility. However, the present invention is not limited to the dope manufacturing apparatus and method shown here. The dope manufacturing facility 10 includes a solvent tank 11 for storing a solvent, a hopper 12 for supplying a solid electrolyte, an additive tank 15 for storing an additive, a solvent, a solid electrolyte, and an additive. A mixing tank 17 to be mixed into the mixed liquid 16, a heating device 18 for heating the mixed liquid 16, a temperature regulator 21 for adjusting the temperature of the heated mixed liquid 16, and a temperature regulator 21. A first filtration device 22 that filters the mixed liquid 16 that has come out to form a dope 24, a flash device 26 that adjusts the concentration of the dope 24, and a second filtration device 27 that filters the concentration-adjusted dope 24. With. Further, the dope manufacturing facility 10 is provided with a recovery device 28 for recovering the solvent generated in the flash device 26 and a regeneration device 29 for regenerating the recovered solvent. The dope manufacturing facility 10 is connected to a film manufacturing facility 33 via a stock tank 32. In addition, although the valves 36-38 for adjusting the amount of liquid feeding and the pumps 41 and 42 for liquid feeding are provided in the dope manufacturing equipment 10, about the increase / decrease in the position and number where these are arrange | positioned It is changed appropriately.

  The flow of manufacturing the dope 24 using the dope manufacturing facility 10 will be described below. By opening the valve 37, the solvent is sent from the solvent tank 11 to the mixing tank 17. Next, the solid electrolyte is fed into the mixing tank 17 from the hopper 12. At this time, the solid electrolyte may be continuously fed to the mixing tank 17 by sending means for continuously measuring and sending, or may be fed to the mixing tank 17 by sending means for weighing and sending a predetermined amount. It may be sent intermittently. Further, from the additive tank 15, the necessary amount of an additive solution prepared by mixing the additive with a desired solvent in advance is sent from the additive tank 15 to the mixing tank 17 by opening and closing the valve 36.

  In addition to the method of sending the additive as a solution, for example, when the additive is liquid at room temperature, the additive can be fed into the mixing tank 17 in the liquid state. Further, when the additive is solid, a method of feeding into the mixing tank 17 using a hopper or the like is also possible. When a plurality of types of additives are added, a solution in which a plurality of types of additives are dissolved can be placed in the additive tank 15. Alternatively, it is also possible to use a plurality of additive tanks and put a solution in which the additive is dissolved in each of them and send them to the mixing tank 17 through independent pipes. In addition, it is preferable to use the solvent used when preparing dope for the solvent which prepares an additive solution.

  In the above description, the order of putting in the mixing tank 17 is the solvent, the solid electrolyte, and the additive, but is not limited to this order. For example, a preferred amount of solvent can be fed after the solid electrolyte is fed into the mixing tank 17. In addition, the additive is not necessarily limited to mixing the solid electrolyte and the solvent in the mixing tank 17, and may be mixed into the mixture of the solid electrolyte and the solvent in an in-line mixing method or the like in a later step.

  The mixing tank 17 encloses the outer surface thereof, a jacket 46 supplied with a heat transfer medium between the mixing tank 17, a first stirrer 48 rotated by a motor 47, and a second stirrer 52 rotated by a motor 51, It has. The mixing tank 17 supplies the heat transfer medium to the inside of the jacket 46 and circulates it to adjust the temperature inside. The internal temperature of the mixing tank 17 is preferably in the range of −10 ° C. to 55 ° C. By appropriately selecting and using the types of the first stirrer 48 and the second stirrer 52, the mixed liquid 16 in which the solid electrolyte is swollen with the solvent is obtained. The first stirrer 48 preferably has an anchor blade so that the solid electrolyte and the solvent can be mixed efficiently and effectively, and the second stirrer 52 is a dissolver type eccentric stirrer. Preferably there is.

  Next, the liquid mixture 16 is sent to the heating device 18 by the pump 41. The heating device 18 is preferably a jacketed tube having a tube body (not shown) and a jacket (not shown) for passing a heat transfer medium between the tube body, and further, the mixed liquid 16 is added. It is preferable to have a pressurizing part (not shown) for pressing. By using such a heating device 18, the solid content in the mixed solution 16 can be effectively and efficiently dissolved under heating conditions or pressure heating conditions. Hereinafter, such a method of dissolving a solid component in a solvent by heating is referred to as a heating dissolution method. In the heating dissolution method, it is preferable to heat the mixed solution 16 so as to be 60 ° C to 250 ° C.

  Note that the solid component may be dissolved in a solvent by a cooling dissolution method instead of the heating dissolution method. The cooling dissolution method is a method of proceeding dissolution while cooling the mixed solution 16 so that the temperature of the mixed solution 16 is maintained or lower. In the cooling dissolution method, the mixed solution 16 is preferably cooled to a temperature of −100 ° C. to −10 ° C. The solid electrolyte can be sufficiently dissolved in the solvent by the heating dissolution method or the cooling dissolution method as described above.

  After the liquid mixture 16 is brought to about room temperature by the temperature controller 21, it is filtered by the first filtration device 22 to remove foreign matters such as impurities and aggregates, thereby obtaining a dope 24. The filter used in the first filtration device 22 preferably has an average pore diameter of 50 μm or less, more preferably 10 μm or less.

  The dope 24 after filtration is sent to the stock tank 32 by the valve 38 and temporarily stored, and then used for film production.

  By the way, as described above, the method in which the solid component is once swollen and then dissolved to form a solution increases the time required for the dope production as the concentration of the solid electrolyte in the solution is increased. May be a problem. In such a case, it is preferable to once make a dope having a concentration lower than the target concentration and then carry out a concentration step to achieve the target concentration. For example, the dope 24 filtered by the first filtering device 22 can be sent to the flash device 26 by the valve 38, and the dope 24 can be concentrated by evaporating a part of the solvent of the dope 24. The concentrated dope 24 is extracted from the flash device 26 by the pump 42 and sent to the second filtration device 27. The temperature of the dope 24 during filtration is preferably 0 ° C to 200 ° C. The dope 24 from which foreign matter has been removed by the second filtration device 27 is sent to the stock tank 32 and once stored, and then used for film production. In addition, since the concentrated dope 24 may contain bubbles, it is preferable to perform a bubble removal process before sending it to the second filtration device 27. As the bubble removal method, for example, various known methods such as an ultrasonic irradiation method for irradiating the dope 24 with ultrasonic waves are applied.

  Further, the solvent gas generated by flash evaporation in the flash device 26 is condensed and recovered as a liquid by a recovery device 28 having a condenser (not shown). The recovered solvent is regenerated and reused as a solvent for dope production by the regenerator 29. Such collection and recycling have advantages in terms of manufacturing costs and are effective in preventing adverse effects on the human body and the environment because they are implemented in a closed system.

  With the above manufacturing method, the dope 24 having a solid electrolyte concentration or a precursor concentration of 5 wt% or more and 50 wt% or less can be manufactured. The solid electrolyte concentration or precursor concentration is more preferably in the range of 10 wt% to 40 wt%. The concentration of the additive is preferably in the range of 1% by weight to 30% by weight when the total solid content in the dope is 100% by weight.

[Film production]
Next, a method for producing a solid electrolyte film will be described. FIG. 2 is a schematic view of the film manufacturing facility 33. However, the present invention is not limited to the film manufacturing method and equipment as shown here.

  In the film manufacturing facility 33, the dope 24 before casting is filtered, and a filtering device 61 for removing coarse particles and foreign matters contained in the dope 24 and the filtered dope 24 are flowed on the support. The casting chamber 63 for forming the casting film 24a and the casting film 24a is peeled off from the support as the film 62, and then the film 62 is held while being transported while holding both side ends of the film 62. A tenter 64 for drying, an edge-cutting device 67 for cutting off both end portions of the film 62, a drying chamber 69 for drying the film 62 over a plurality of rollers 68, and a cooling chamber for cooling the film 62 71, a static elimination device 72 for reducing the amount of charge of the film 62, a knurling roller 73 for embossing the side ends, and a winding chamber 76 for winding the film 62.

  A stirrer 78 that is rotated by a motor 77 is attached to the stock tank 32. By stirring the dope 24 by rotating the stirrer 78, precipitation and aggregation of solids contained therein are suppressed. The stock tank 32 is connected to the filtration device 61 via the pump 80.

The casting chamber 63 includes a casting die 81 that flows out of the dope 24, and a casting band 82 as a traveling support. As a material of the casting die 82, precipitation hardening type stainless steel is preferable, and its thermal expansion coefficient is preferably 2 × 10 ⁻⁵ (° C. ⁻¹ ) or less. And it has almost the same corrosion resistance as SUS316 in the forced corrosion test with electrolyte aqueous solution, and even if it is immersed in a mixed solution of dichloromethane, methanol and water for 3 months, pitting (opening) occurs at the gas-liquid interface. Those having corrosion resistance that do not occur are preferred. The casting die 81 is preferably produced by grinding a material that has passed for one month or more after casting, whereby the dope 24 uniformly flows inside the casting die 81, and the flow described later. Streaks and the like are prevented from occurring in the spread film 24a. The so-called wetted surface in contact with the dope 24 of the casting die 81 preferably has a finishing accuracy of 1 μm or less in terms of surface roughness and a straightness of 1 μm / m or less in any direction. The clearance of the slit of the casting die 81 can be adjusted in the range of 0.5 mm to 3.5 mm by automatic adjustment. The chamfer radius R of the corner portion of the liquid contact portion at the tip of the lip of the casting die 81 is constant and 50 μm or less over the entire width of the casting die 81. The casting die 81 is preferably a coat hanger type die.

  The width of the casting die 81 is not particularly limited, but is preferably about 1.1 to 2.0 times the width of the film 62 as the final product. In addition, a temperature controller that controls the temperature of the casting die 81 is preferably attached to the casting die 81 so that the temperature of the dope 24 during film formation is maintained at a predetermined temperature. Further, it is more preferable that the casting die 81 is provided with a plurality of thickness adjusting bolts (heat bolts) provided at a predetermined interval in the width direction and an automatic thickness adjusting mechanism that adjusts a gap between the slits with the heat bolt. . The heat bolt is preferably subjected to film formation by setting a profile according to the amount of pump 81 (preferably a high precision gear pump) according to a preset program. In order to precisely control the dope feed amount, the pump 80 is preferably a high-precision gear pump.

  In addition, a thickness measuring machine such as an infrared thickness gauge is provided in the film manufacturing facility 33, and feedback control to the automatic thickness adjusting mechanism is performed by an adjustment program based on the thickness profile and a detection result by the thickness measuring machine. Also good. It is preferable to use a casting die 81 that can adjust the slit interval of the tip lip to be ± 50 μm or less so that the difference in thickness at any two positions excluding both side ends of the film 62 as a product is within 1 μm.

More preferably, a cured film is formed at the lip end of the casting die 81. The method for forming the cured film is not particularly limited, and examples thereof include ceramic coating, hard chrome plating, and a nitriding method. In the case of using ceramics as the cured film, it is preferable to use a ceramic that can be ground, has a low porosity, is not brittle, has good corrosion resistance, and has no affinity or adhesion to the dope 24. Specific examples include tungsten carbide (WC), Al ₂ O ₃ , TiN, Cr ₂ O _{3 and the} like. Among them, WC is particularly preferable. The WC coating can be performed by a thermal spraying method.

  In order to prevent the dope 24 from locally drying and solidifying at the lip tip of the casting die 81, it is preferable to attach a solvent supply device (not shown) for supplying a solvent to the lip tip in the vicinity of the lip tip. The position where the solvent is supplied is preferably a peripheral portion of a three-phase contact line formed by both ends of the casting bead, both ends of the lip tip, and the outside air. The flow rate of the supplied solvent is preferably 0.1 mL / min to 1.0 mL / min for each side. Thereby, it is possible to prevent foreign matters, for example, solid components deposited from the dope 24 and those mixed in the casting bead from the outside from being mixed in the casting film 24a. In addition, as a pump which supplies a solvent, it is preferable to use a pulsation rate of 5% or less.

  The casting band 82 below the casting die 81 is stretched around the rotating rollers 85 and 86 and is continuously conveyed by the drive rotation of at least one of the rotating rollers.

  The width of the casting band 82 is not particularly limited, but it is preferable to use a casting band having a range of 1.1 to 2.0 times the casting width of the dope 24. Further, it is preferable that the length is 20 m to 200 m, the thickness is 0.5 mm to 2.5 mm, and the surface roughness is polished to be 0.05 μm or less.

  The material of the casting band 82 is not particularly limited, but is preferably stainless steel. Other materials include non-woven plastic films such as polyethylene terephthalate (PET) film, polybutylene terephthalate (PBT) film, nylon 6 film, nylon 6,6 film, polypropylene film, polycarbonate film and polyimide film. It is preferably a long product having chemical stability and heat resistance that can cope with the organic solvent used and the film forming temperature. In this embodiment, a casting band 82 made of SUS that is not dissolved in the solvent to be used is used.

  The rotating rollers 85 and 86 are preferably provided with a heat transfer medium circulating device 87 for supplying the heat transfer medium to the rotating rollers 85 and 86 and controlling the surface temperature of the rollers. The surface temperature is set to a predetermined value. In the present embodiment, a heat transfer medium flow path (not shown) is formed in the rotation rollers 85 and 86, and the heat transfer medium maintained at a predetermined temperature passes through the flow path to rotate. The temperature of the rollers 85 and 86 is maintained at a predetermined value. The surface temperature of the casting band 82 is appropriately set according to the type of solvent, the type of solid component, the concentration of the dope 24, and the like.

Instead of the rotating rollers 85 and 86 and the casting band 82, a rotating drum (not shown) can be used as a support. In this case, it is preferable that the rotation can be performed with high accuracy so that the rotation speed unevenness is 0.2% or less. The rotating drum preferably has an average surface roughness of 0.01 μm or less, and preferably has a surface subjected to a hard chrome plating treatment or the like. Thereby, sufficient hardness and durability can be improved. In addition, it is preferable that the surface defects of the rotating drum, the casting band 82, and the rotating rollers 85 and 86 are suppressed to a minimum. Specifically, there is no pinhole of 30 μm or more, and the number of pinholes of 10 μm or more and less than 30 μm is 1 / m ² or less, and the number of pinholes of less than 10 μm is preferably ² / m ² or less.

  In the vicinity of the casting die 81, a decompression chamber 90 is preferably provided to control the pressure upstream of the casting bead formed from the casting die 81 to the casting band 82 in the traveling direction of the casting band 82. .

  In the vicinity of the casting band 82, there are first to third air ducts 91 to 93 that blow wind to evaporate the solvent of the casting film 24a, and wind that disturbs the shape of the casting film 24a. In order to suppress hitting 24a, the first air duct disposed closest to the casting bead among the air ducts is provided with a wind shielding plate 94.

  The casting chamber 63 is provided with a temperature control device 97 for keeping the internal temperature at a predetermined value, and a condenser (condenser) 98 for condensing and recovering the volatile organic solvent. A recovery device 99 for recovering the organic solvent condensed and liquefied by the condenser 98 is provided outside the casting chamber 63.

  A blower 102 is provided in the transition portion 101 downstream of the casting chamber 63. Further, a tenter 64 provided with a clip 64a and an air supply duct 64b for supplying dry air and an edge-cutting device 67 for cutting both side ends of the film 62 are provided downstream thereof. The ear clip device 67 is provided with a crusher 103 for finely cutting both end portions of the cut film 62.

  An adsorption recovery device 106 for adsorbing and recovering the solvent gas generated by evaporation from the film 62 is attached to the drying chamber 69. In FIG. 2, a cooling chamber 71 is provided downstream of the drying chamber 69, but a humidity control chamber (not shown) for adjusting the water content of the film 62 between the drying chamber 69 and the cooling chamber 71. May be provided. The static eliminator 72 is a forced static eliminator such as a static eliminator, and can adjust the charged voltage of the film 62 so as to be within a predetermined range (for example, −3 kV to +3 kV). The static eliminator 72 is illustrated as being disposed on the downstream side of the cooling chamber 71, but is not limited to this installation position. The knurling imparting roller pair 73 imparts knurling to both end portions of the film 62 by embossing. Inside the take-up chamber 76, a take-up roll 107 for taking up the film 62 and a press roller 108 for controlling the tension during the take-up are provided.

  Next, the stretch drying process which is a specific method of the present invention will be described. FIG. 3 is a schematic diagram of a tenter 64 used in the present embodiment according to the present invention. In the tenter 64, in addition to the clip 64a and the air supply duct 64b, a pair of endless chains 110 to which a plurality of clips 64a are attached at a predetermined pitch, a rail 112 for guiding the travel of the chain 110, and the chain 110 are wound. A chain sprocket 114 to be hung and a drive unit 115 that rotationally drives the chain sprocket 114 are provided.

  The film 62 sent through the crossing part 101 is gripped at both ends by the clips 64a at the tenter inlet 120. Thereafter, the chain 110 travels on the rail 112, and the film 62 is stretched in the width direction so as to correspond to the rail interval, whereby the film 62 is stretched in the width direction. At the tenter outlet 121, when the clip 64a is opened, the holding of the film 64 whose drying has been promoted is released. In addition, the drive part 115 is installed in any one of the tenter inlet 120 and the tenter outlet 121, and is installed so that the chain sprocket 114 which faces may be interlocked. However, the installation location is not particularly limited.

  The rails 112 in the introduction part are set so that the rail interval is the same for a certain period of time. In the next stretching part, the gripping width A of the film 62 at the stretching part inlet 123 gradually becomes larger in the film transport direction. The rail interval is set so as to increase. Thereby, the film 62 is stretched in the width direction. In addition, since the extending | stretching part inlet_port | entrance 123 is the same as an introduction part exit, it attaches | subjects the same code | symbol.

  In the stretching relaxation section, the rail interval is set so that the grip width of the film 62 at the stretching relaxation section outlet 125 decreases in the film transport direction with respect to the grip width B of the film 62 at the stretching relaxation section inlet 124. Has been. Thereby, since it acts so that stress relaxation acts with respect to the stretched film 62, drying can be accelerated | stimulated, suppressing shrinkage force. In addition, since the extending | stretching relaxation part inlet_port | entrance 124 is the same as an extending | stretching part exit, it attaches | subjects the same code | symbol.

  As described above, after the gripping width A (mm) of the film 62 in the introduction portion, the maximum gripping width B (mm) of the stretching portion in the stretching portion, and the gripping width of the film 62 are reduced, the film 64 is separated from the clip 64a. The width C (mm) of the film 62 is preferably set so that A, B, and C satisfy the condition of 1 <100 × (BC) / A <15. Thereby, it can suppress that a shape change generate | occur | produces, such as a wrinkle and a twist producing | generating in the film 62. FIG. However, in the above condition, when 0 <A, the film 62 contracts due to the evaporation of the solvent in a state where the amount of the volatile solvent of the film 62 is very large, so that the shape changes greatly. . On the other hand, in the case of A <C, since tension does not act on the film 62, wrinkles, wrinkles and the like are generated, the surface becomes a chimmen-like shape, and the flatness is significantly deteriorated. The grip widths representing A, B, and C are defined as the length between grip positions of the clip 64a when the film 62 is gripped by the clip 64a.

  Next, an example of a method for manufacturing the film 62 using the film manufacturing facility 33 (see FIG. 2) will be described below.

  Next, an example of a method for manufacturing the film 62 using the film manufacturing facility 33 will be described. The tenter 64 is of the form shown in FIG.

  In the stock tank 32, the dope 24 is always made uniform by the rotation of the stirrer 78. Thereby, precipitation and aggregation of solid content in the dope 24 are suppressed until it is cast. Here, the dope 24 may be mixed with various additives as needed during the stirring. And the dope 24 is filtered with the filtration apparatus 61, and the foreign material of a size more than predetermined particle size and a gel-like foreign material are removed.

The dope 24 is cast from the casting die 81 to the casting band 82. The relative position of the rotary roller 85 and the rotary roller 86 and / or the rotational speed of at least one of them is adjusted so that the tension generated in the casting band 82 is 10 ³ N / m × 10 ⁶ N / m. The relative speed difference between the casting band 82 and the rotating rollers 85 and 86 is preferably set to 0.01 m / min or less. At the time of casting, the casting amount of the dope 24 is determined in consideration of the concentration of the dope 24 to be used and the desired thickness of the film product.

  It is preferable that the speed fluctuation of the casting band 82 is 0.5% or less, and the meandering in the width direction that occurs when the casting band 82 makes one round is 1.5 mm or less. In order to suppress this meandering, a detector (not shown) that detects the positions of both ends of the casting band 82 and a position adjuster (not shown) that adjusts the position of the casting band 82 according to the detection data from this detector. It is more preferable to provide feedback control of the position of the casting band 82. Further, it is preferable that the position fluctuation in the vertical direction associated with the rotation of the rotary roller 85 is within 200 μm for the casting band 82 immediately below the casting die 81. The temperature of the casting chamber 63 is preferably set to −10 ° C. to 57 ° C. by the temperature controller 97. The solvent evaporated in the casting chamber 63 is recovered by the recovery device 99 and then regenerated and reused as a solvent for dope production.

  The inside of the casting chamber 63 is preferably kept as low as possible by adsorbing and recovering the evaporated solvent as described above, and the humidity is preferably 50% RH or less. When the humidity is high, the casting membrane absorbs moisture in the air, so there are cases where the layers are separated and the porosity is increased, but by reducing the humidity as described above, A few cast films can be formed. More preferably, the humidity is 20% RH or less. In this embodiment, 10% RH is set.

  A casting bead is formed from the casting die 81 to the casting band 82, and a casting film 24 a is formed on the casting band 82. In order to stabilize the state of the casting bead, the decompression chamber 90 is preferably controlled so that the upstream area of the bead has a predetermined pressure value. The reduced pressure value is preferably set to −2500 Pa to −10 Pa from the area on the downstream side with respect to the bead. It is preferable to attach a jacket (not shown) to the decompression chamber 90 so that the internal temperature is maintained at a predetermined temperature. In order to keep the shape of the casting bead desired, it is preferable to attach a suction device (not shown) to the edge portion of the casting die 81 to suck both sides of the bead. The edge suction air volume is preferably in the range of 1 L / min to 100 L / min.

  After the casting film 24a has a self-supporting property, the casting film 24a is peeled off from the casting band 82 while being supported by the peeling roller 109 to form a film 62 containing a solvent. The film 62 is fed to the tenter 64 after being supported by a plurality of rollers and conveyed through the crossing section 101. In the crossing portion 101, it is possible to apply a draw tension to the film 62 by making the rotational speed of the downstream roller faster than the rotational speed of the upstream roller. Moreover, in the crossover part 101, the drying air of desired temperature is sent to the film 62 vicinity from the air blower 102, or it sprays directly on the film 62, and the drying advances. At this time, the temperature of the drying air is preferably 20 ° C to 250 ° C.

  Drying of the film 62 sent to the tenter 64 is promoted by supplying dry air from an air supply duct 64b provided inside the tenter 64 while both ends of the film 62 are gripped and conveyed by the clips 64a. The As shown in FIG. 3, the tenter 64 used in the present embodiment changes the distance between the clips 64a facing each other at both end portions of the film for the purpose of changing the width of the film 62 to be conveyed. The rail spacing is adjusted so that In the present embodiment, in the tenter 64, the grip width of the film 62 is first kept constant. Next, the grip width is expanded and then contracted, and finally the grip width is held constant.

  In general, when the film 62 containing a large amount of solvent is dried, the total amount of the solvent that evaporates from the film 62 increases as the drying progresses, so that the film 62 easily contracts in the width direction. This tendency becomes more prominent as the drying temperature is higher. However, when the shrinkage occurs, the flatness of the film decreases because the shape change is induced. Therefore, in the present invention, since the holding width of the film 62 to be conveyed is provided in a stepwise manner by providing a stretching and drying step, the film 62 is prevented from shrinking in the width direction and has good flatness. A solid electrolyte film can be produced. When the tension applied to the film 62 is adjusted in this manner, the orientation can be adjusted by controlling the expansion and contraction of the film 62 in the width direction, so that excellent mechanical strength can be imparted to the film 62. .

  In the stretching and drying step, it is preferable to blow dry air on the film by a drying means having a blower opening. In the present embodiment, an air supply duct 64b that has a large number of air outlets and can blow dry air adjusted to a predetermined temperature directly onto the film is used. In addition, if the drying temperature is different while changing the length in the width direction of the film, the shape of the film may be greatly changed due to the influence of the temperature. For this reason, it is preferable to keep the temperature of the drying air substantially constant while changing the grip width of the clip 64a.

  The film after peeling from the support contains a large amount of solvent. Therefore, when such a film is dried, it is preferable to provide a plurality of drying steps having different drying temperatures and dry it stepwise. And in order to prevent that a solvent evaporates rapidly and a film changes shape, the temperature which dries the film after peeling from a casting support body is 3-4 steps in the range of 40 to 140 degreeC. It is preferable to increase the temperature gradually according to the temperature. For example, when a blower capable of supplying dry air is used as the drying means, the temperature of the dry air is adjusted to satisfy the above range. The drying means includes a tenter.

  In the stretching and drying step, as in the present embodiment, both side ends of the film are fixed with gripping means such as clips and pins, and the distance between the gripping means is widened in the horizontal direction to stretch the film in the width direction. A stretching machine can be preferably used. In addition, it is preferable to divide the inside of the tenter into different temperature zones and adjust the drying conditions appropriately for each of the compartments.

  As a drying means provided in the tenter, a temperature control device such as an infrared heater may be used in place of the above air supply duct. At this time, the whole area of the tenter may be heated, or each part may be heated, and there is no particular limitation. When an infrared heater or the like is used, the film is dried while adjusting the heat generation temperature by the heater.

  Regarding the tenter, when drying the film while maintaining the width with the tenter, the drying gas blowing method, blowing angle, wind speed distribution, wind speed, air volume, temperature difference, air volume difference, upper and lower blowing air volume ratio, use of high specific heat drying gas, etc. By appropriately controlling, it is possible to ensure prevention of quality deterioration such as flatness when the speed by the solution casting method is increased or the width of the film is widened.

  In the present embodiment, a clip is employed, but there is no particular limitation as long as both end portions of the film can be gripped or opened. For example, a pin may be applied instead of the clip, and a predetermined position of the film may be pierced and held by the pin. Moreover, as a material of the part which contacts a film directly, a metal material and rubber | gum are mentioned, However, In order not to damage a film, it is preferable that it is rubber | gum. However, since a basic reaction liquid or the like may be applied to the surface of the film, it may be preferable to use a stainless steel material from the viewpoint of base resistance or the like.

  In at least one of the crossover part 101 and the tenter 64, at least one direction of the film 62 in the casting direction and the width direction is 100.5% to 300% of the dimension before stretching. It is preferable to stretch as described above.

  The film 62 is dried to a predetermined residual solvent amount by the tenter 64, and then both end portions thereof are cut and removed by the edge-cutting device 67. The separated both end portions are sent to the crusher 103 by a cutter blower (not shown). By the crusher 103, the side end portion is crushed into chips. Since this chip is reused for dope manufacturing, the raw material can be effectively used. In addition, although it can also abbreviate | omit about the cutting process of this both-sides edge part, it is preferable to carry out in either from the casting process to the process of winding up a film.

  The film 62 from which both end portions have been cut and removed is sent to the drying chamber 69, where drying is further promoted. The internal temperature of the drying chamber 69 is not particularly limited, but is determined according to the heat resistance (glass transition point Tg, heat distortion temperature, melting point Tm, continuous use temperature, etc.) of the solid electrolyte, and is Tg or less. It is preferable. The internal temperature of the drying chamber 69 is preferably 120 ° C. or higher and 185 ° C. or lower, and is preferably dried until the residual solvent amount of the film 62 is less than 10% by weight. In the drying chamber 69, as the film 62 is dried, the solvent evaporates from the inside to become solvent gas. Therefore, the solvent gas is adsorbed and recovered by the adsorption recovery device 106. The air from which the solvent component has been removed by the adsorption recovery device 106 is sent again as dry air into the drying chamber 69.

  In addition, it is more preferable that the drying chamber 69 is divided into a plurality of sections in order to change the blowing temperature. In addition, if a preliminary drying chamber (not shown) is provided between the ear opener 67 and the drying chamber 69 to preliminarily dry the film 62, the film temperature is prevented from rising rapidly in the drying chamber 69. The shape change of the film 62 at 69 can be suppressed.

  The film 62 is cooled to approximately room temperature in the cooling chamber 71. When a humidity control chamber is provided between the drying chamber 69 and the cooling chamber 71, it is preferable to blow air adjusted to a desired humidity and temperature onto the film 62 in the humidity control chamber. In addition, when providing a humidity control chamber, it is preferable that the internal temperature shall be 20 degreeC or more and 30 degrees C or less, and the humidity shall be 40 RH% or more and 70 RH% or less. Thereby, it is possible to suppress the occurrence of curling of the film 62 and winding failure when winding.

  In the solution casting method, various steps such as a drying step and a side edge portion excision and removal step are performed before the film (solid electrolyte film) peeled off from the support is wound up. In each of these processes or between each process, the film is mainly supported or conveyed by a roller. These rollers include a driving roller and a non-driving roller, and the non-driving roller is mainly used for determining a film conveyance path and improving conveyance stability.

  The neutralizing device 72 sets the charged voltage while the film 62 is being conveyed to a predetermined value. Further, the film 62 is preferably imparted with knurling by a knurling roller pair 73. In addition, it is preferable that the height of the unevenness | corrugation of the knurled location is 1 micrometer-200 micrometers.

  Then, the film 62 is taken up by the take-up roll 107 in the take-up chamber 76. It is preferable to wind the film while applying a desired tension to the film 62 by the press roller. It is more preferable to gradually change the tension from the start to the end of winding, thereby preventing excessive winding in the film roll. The width of the film 62 to be wound is preferably 100 mm or more. The present invention is also applied to the production of a thin film having a film thickness of 5 μm or more and 300 μm or less.

  In the present invention, when casting the dope 24, a method in which two or more kinds of dopes are simultaneously laminated co-cast or sequentially laminated co-cast may be used. When performing simultaneous lamination and co-casting, a casting die to which a feed block is attached may be used, or a multi-manifold casting die may be used. As for the film which consists of a multilayer by co-casting, it is preferable that any one of the two layers exposed on the surface is 0.5% to 30% of the total thickness of the film. Further, in the case of simultaneous lamination co-casting, the concentration of each dope is set in advance so that when the dope is cast from the die slit to the support, the high-viscosity dope is wrapped and cast by the low-viscosity dope. It is preferable to adjust. In the case of simultaneous lamination and co-casting, the bead formed from the die slit to the support is in contact with the outside world, that is, the exposed dope has a larger proportion of the poor solvent than the internal dope. It is preferable.

The film width at an arbitrary position in the drying process is defined as A1 (mm) after peeling the cast film from the support as a film for the purpose of producing a stable flat surface with no variation in lots. And the width of the film at the position where the residual solvent ratio was reduced by 10% from that position was B1 (mm), and the shrinkage rate Sa between them was Sa = {(A1-B1) / A1} × 100 When Sa ≦ 5, there is a method of carrying dry. At this time, as a more preferable aspect, it is preferable that the roller first contacted with the film after peeling from the support is a driving roller, and when the film is introduced into the tenter, the elastic modulus in the width direction of the film is it is preferably ^{1.5kg / mm 2 ~400kg / mm 2} .

And in a drying process, it is preferable to convey as the tension | tensile_strength to the conveyance direction of a film as 9.8N / m-490N / m, and the roller used at the process (henceforth a dry conveyance process) dried while conveying is used. It is preferable that the tension is applied toward the outer side in the width direction of the roller. Further, when the friction coefficient of the surface with respect to the width direction of the roller is the maximum value μ _max and the minimum value μ _min , the ratio H μ of the maximum value and the minimum value is H μ = μ _max / μ _min ≧ 1. It is preferable to carry using the roller which is 2.

The film during the drying conveying step, the residual solvent rate immediately before applying the coating solution containing a solvent having a swelling property and Y _0, the width length of the position is C, after the final drying transport step It is preferable to dry as Se = 0.15Y ₀ +0.57, where D is the width and the shrinkage ratio Sc is Sc = {(C−D) / C} × 100. Further, the roller diameter is preferably 5 to 30 cm (especially 10 to 20 cm is preferable), the friction coefficient is preferably 0.12 to 0.8, and the minimum value is preferably 0.1 to 0.5.

In order to obtain good flatness, static elimination is performed in the vicinity of the peeling portion (in the present embodiment, in the vicinity of the peeling roller 109) where the film is peeled off from the casting support or until the drying is finished after peeling. It is preferable to provide the device 72 and set the surface voltage of the film to -5 to +5 kV. More preferably, the charged voltage after static elimination is -3 kV to +3 kV. In addition, it is preferable that a static elimination apparatus sprays the gas containing ion, and it is preferable that the oxygen concentration in the gas containing this ion shall be 10 volume% or less. The ground leakage resistance of the roller in contact with the casting support and / or the film is preferably 10 ⁶ Ω or less, and the surface temperature of the film when peeling from the casting support is determined by the vapor pressure of the organic solvent. The temperature is preferably 6650 Pa or less. Furthermore, it is preferable to provide a static elimination bar or static elimination yarn immediately after the stripping roller.

  As a preferable method for setting the surface voltage of the film during film formation to a range of −5 to +5 kV, for example, the material of the other roller with which the film during roller conveyance comes into contact is determined from the charged train. In addition, a method in which the charged column is located at a position where the charge amount is small with respect to the film, or the casting support (in this embodiment, the casting band 82) and the surface of the roller are appropriately roughened to contact the film. A method of reducing the area, a method of reducing the contact area with the casting support or roller by adding a matting agent in the film or coating a composition containing the matting agent on the surface, A method of improving the conductivity of the film by containing or applying a conductive material on the surface, a method of reducing the surface leakage resistance of the film by increasing the relative humidity of the external atmosphere, and ionizing the gas to ionize the film A method of neutralizing the charge on the surface of the soldered film, a method of reducing the surface potential of the film using a static eliminator, or a method of causing the tip discharge with a grounded needle-like or linear metal to leak the charge on the film surface These methods can be used in combination.

  The neutralization device may be any device that can remove or reduce static electricity from the film, and examples thereof include a neutralization bar, a neutralization yarn, or an ion blowing type neutralization device. Among these, an ion blowing type neutralization device is preferably used. The ion blower type static eliminator is an apparatus having a structure in which gas is ionized by corona discharge, flame plasma, ultraviolet rays, a heated metal body, a radioisotope, or the like to generate ions, and the generated ions are blown onto an object. The static eliminator using corona discharge is composed of an electrode unit with a built-in high-voltage transformer, a blowing unit, a gas supply unit, a controller, and the like. The electrode unit generates corona discharge, ionizes the gas, and blows out the unit. The ionized gas is sprayed onto the object. Furthermore, air is usually used as the gas to be supplied. However, by introducing an inert gas so that the oxygen concentration in the gas is 10% by volume or less, the effect of improving safety against dangerous substances can be obtained. It has been shown that The type of inert gas may be a gas such as nitrogen, carbon dioxide, or argon. Nitrogen and carbon dioxide are preferable from the viewpoint of cost, and a method of supplying these gases by providing a flow meter in the gas supply unit is preferable.

  The neutralizing yarn is usually a flexible yarn, for example, 12/300 × 3 manufactured by Naslon. Further, the distance between the static elimination device and the film is preferably 10 mm to 100 mm, and the place where the static elimination device is installed is preferably a distance of 10 mm to 100 mm as the length of the film after peeling after peeling the film from the casting band. The vicinity of the peeling roller is preferable, but it may be between the casting band and the peeling roller. However, the film is preferably after the peeling roller because of film cutting and personal danger. Furthermore, the place where the static elimination layer device is installed is preferably a distance of 10 mm to 1000 m (more preferably 10 to 500 m) from the peeling roller after the film peeling position from the casting band, and particularly in the vicinity of the peeling roller. The static eliminator may be installed on any surface of the film.

  Stable peeling of high residual solvent film is possible under high-speed film formation, and in order to obtain good flatness, immediately after peeling the film from the casting band, the surface of the film that has been in close contact with the support side is first There is a method in which the film is brought into contact with the second roller, and then the surface of the film on the air side on the casting band is brought into contact with the second roller and then dried. At this time, as a more preferable aspect, the roller that contacts first is smaller as the diameter of the roller becomes the center, and the second roller is a roller that increases in diameter as the diameter of the roller becomes the center. The film is peeled off from the casting band and first passed through a nip roller and dried. Immediately after the film is peeled off from the casting band, the angle θ between the plane of the film and the roller shaft and (180 ° −θ ′ ) And two small rollers having a relationship of θ and θ ′ of θ> 0 ° and θ ′ <90 ° are applied to both ends of the film surface that is in close contact with the casting band, It is preferred that the first roller is brought into contact with the surface of the film that was on the air side on the casting band and then dried. Also, it is preferable to dry the film after contacting the film with the first roller whose position changes according to the amount of residual solvent immediately after peeling or according to the surface temperature of the film at the time of peeling. Apply a vertical slit wind of wind speed of 20 m / sec or more from the nozzle installed above the film to the film surface that was in close contact, and then apply the first roll to the film surface that was on the air side on the casting band. After contact, drying, the vertical slit wind speed distribution in the width direction of the film gradually increases from the center to both ends, the film is peeled off from the casting band, and the film remains at the time of peeling. By changing the position of the second roller in contact with the film according to the amount of solvent, the wrap angle at which the film contacts the first roller is changed, and the film is in contact with the second roller. Be dried after being, it is preferable that the surface temperature of the first roller has a distribution that decreases toward both ends from the central portion in the longitudinal direction of the roller.

  Further, after the cast film is peeled from the casting band as a film, the surface temperature Tr of the roller that first contacts the film and the surface temperature Tb of the support at the time of peeling satisfy (Tr−Tb) ≦ 50 ° C. Then, it is preferable to dry. In another preferred embodiment, the surface temperature Tr of the roller has a distribution in which the roller surface temperature Tr decreases from the center to both ends in the length direction of the roller, and the surface roughness Ra of the roller with which the film immediately after formation first contacts is distributed. For example, Ra ≦ 1.0 μm. In addition, what is necessary is just to give the speed change of 1.001 to 1.100 as a drive roller.

  In order to improve flatness and prevent scratches and breakage at both ends, there is no contact with the air side surface on the casting band at least immediately after the peeling roller to the entrance of the tenter. It is preferable to carry. In this embodiment, the crossover part 101 is provided. As a more preferred embodiment, there is a means for conveying the film without contact with respect to the air side surface on at least the casting band of the film, and the number of conveying rollers in contact with the air side surface is within three. The film transport distance of the means for transporting in a non-contact manner is 10% to 60% of the film transport distance from immediately after the peeling roller to the exit of the tenter. Further, the non-contact conveying means is of an air floater type that blows air on both sides of the film, the one that grips both ends of the film, and the surface on the casting band side on the casting band of the film. It is at least one selected from the suction-roll type that comes into contact, and the ambient temperature of the means for carrying without contact through a film having a residual solvent amount of 20% to 130% by weight passing through the means for carrying without contact It is also preferable to pass the film through the apparatus at 40 ° C. or lower.

  In addition, the apparatus having a means for conveying without contact can be an air floater type, a device capable of gripping both ends of the film with a clip or a nip roller, or a suction roller type. Furthermore, both ends of the film are gripped by a movable caterpillar belt and conveyed without contact, and both ends of the film are gripped by a plurality of narrow nip rollers and conveyed without contact. Etc. can also be used. Further, as a detailed mode of the nip roller type, the plurality of pairs of rollers to be niped are preferably easier to grip than those having an uneven shape, have unevenness for embossing, and the upper and lower sides are male and female. It is a meshing type. The shape of the concavo-convex shape, size, and height, such as a sharp tip or groove shape, can be firmly grasped, and the pressure of a plurality of pairs of nip rollers is preferably 30 Pa to 500 Pa. In addition, More preferably, it is 50Pa-200Pa.

  In the method of producing a solid electrolyte film using a solution casting film forming apparatus, a film having a residual solvent amount after peeling of 10% by weight to 150% by weight with a surface roughness Ry for the purpose of preventing the roller from becoming dirty. Is 0.6 μm or less and the surface energy at 20 ° C. is conveyed while contacting with a roller having a surface energy of 70 to 100 mN / m. Further preferred embodiments are that the first one of the rollers is a stripping roller, that the roller is the only roller in contact with the air side surface of the film on an endless casting band that moves indefinitely, It is a solution casting film forming apparatus having a hard chrome plating, a roller diameter of 85 to 300 mm, and a roller and a roller surface cleaning means, and the cleaning means moves while moving in the roller axial direction. It is mentioned that it has a means for adhering the solvent to the roller and a means for wiping the roller surface adjacent thereto. As a method of attaching the organic solvent to the roller, the organic solvent is supplied by capillary action, or is wiped with a nonwoven fabric containing the organic solvent, or the organic solvent is dissolved in the solid electrolyte. It can also be mentioned as a preferred embodiment that the organic solvent is a mixed solution of a good solvent having a solubility in a solid electrolyte and a poor solvent having no solubility.

Furthermore, in order not to generate wrinkles or sagging in the film, a method of adsorbing and transporting the film using a hollow drive roller that can be decompressed is also included for the process of residual solvent amount of 40% by weight or less. As a more preferred embodiment, a plurality of suction ports are formed over the entire circumference in at least a part of the peripheral wall of the drive roller, and the outer peripheral surface of the suction port is a metal mesh (the mesh size of the metal mesh is 0.5 to 50 mm ^2). ), A plurality of suction ports are formed over the entire circumference in at least a part of the peripheral wall of the drive roller, and the outer peripheral surface is a perforated plate (the size of the through hole of the perforated plate). be coated with a cover made of Saga 0.5mm ² ~50mm ^2), the portion where the suction port is formed in the peripheral wall of the driving roller the film or the ratio of the length of the width direction of the film, the film or film 0.1 to 1 with respect to the entire width, the suction port on the peripheral wall of the drive roller is a circle, an ellipse, or a polygon more than a pentagon, That is come is a ^{1 mm} 2 100 mm ^2, the suction port in the peripheral wall of the drive roller, that are formed 30 mm × 30 mm 1 or more per range, it like the outer diameter of the drive roller is 65~450mm is Can be mentioned.

  Furthermore, a drive shaft that is rotationally driven by a motor or the like is fixed to the lid that closes the opening at both ends of the peripheral wall of the drive roller, and the drive roller that is fixed to one of the lids has a drive roller over its entire length. A suction path leading to the inside of the is formed. And the inside of a drive roller is pressure-reduced through a suction path with a vacuum pump. The air sucked by the vacuum pump is sent to a solvent recovery device, where the solvent in the solvent dissolving the solid electrolyte is recovered.

  For the purpose of producing a thin film at a high speed, the surface temperature of the film is 50 to 100 ° C. by the roller group conveying means in which the crossing zones are arranged in a staggered manner in the roller group conveying means arranged in a staggered manner. There is a method of transporting with a passage time of 10 to 70 seconds while heating to be. Further, as a preferable aspect, the widest roller interval of the roller conveying means is set to the film width at the time of peeling at the maximum, the roller interval is set to 900 mm or less, and it is dried on an endless support that moves infinitely. The film may be conveyed while the air side surface of the film is brought into contact with a conveying means selected from a drum and an arched roller.

  Further, the film is passed between the peeling roller and the tenter entrance so that the residual solvent amount of the film is 30% by weight to 120% by weight, and the surface temperature of both ends of the film becomes 50 ° C. or more in the meantime. It is preferable that the film is heated, and there is a method in which the means for heating both ends of the film is selected from irradiation of near infrared rays or far infrared rays and hot air blowing. Further, after heating both ends of the film, the same part may be cooled by a cooling roller, and further, the residual solvent amount of the film is passed between 30% by weight and 120% by weight between the peeling roller and the entrance of the tenter. In the meantime, it is also preferable to attach an organic solvent having solubility or swelling ability to the film at both ends of the air-side surface of the film when it is dried on an endless support that moves infinitely. In addition, you may cut off the both ends of a film with the width | variety within 50 mm from an end in the area | region whose residual solvent amount after peeling is 50 weight% or less.

  Even if it is a thin film of 20 to 60 μm, the residual solvent amount at the time of winding is set to 0.05% by weight or less for the purpose of eliminating deformation over time, eliminating scratches, and eliminating bubbles and undissolved substances. In addition, a tension blocking device is provided between the peeling roller and after and the winding chamber, and the tension between the peeling film from the support and the tension blocking device is set to 1 N / m to 100 N / m, There is a method of conveying a film. Furthermore, as a preferable aspect, the distance between the peeling position and the tension breaking device is 2 m to 90 m as the length of the film, the conveying means between the peeling position and the tension breaking device is a guide roller and / or an air float, guide For example, a part or all of the rollers are tendency rollers.

  In order to control the dimensional stability and flatness, in the drying and transporting process after peeling from the casting band as a film and winding it, the stretching rate in the transport direction is MD, and the stretch rate in the width direction is When TD is set, there is a method of −4% ≦ MD−TD ≦ 4% and −6% ≦ MD + TD ≦ 6%. As a more preferable embodiment, when the expansion / contraction ratio in the width direction of the film in the region after the film is peeled from the casting band 82 and first stretched in the width direction is TD1, TD1 ≧ −6% may be set.

  Also, in order to prevent deformation such as curling and bending of both ears caused by the difference in drying speed between the front and back, when the amount of residual solvent at the time of peeling is 60% by weight or less, the peeling position where the film is peeled off from the casting band Up to 10 seconds outward from both side edges of the film on the roller and 2 cm away from the roller surface at the transfer portion, the boiling point of the main solvent to (boiling point +30) ° C. There is a way to make it.

  Further, in order to suppress the occurrence of planar defects due to the agglomerated components of the solvent, at the transition part, when the residual solvent amount of the peeled film is 60% by weight or less, at least the endless support within 10 seconds after peeling. It is also possible to supply air to the film surface that has been in contact.

  In addition, there is a method of adhering an organic solvent to the film for curling suppression at the transition portion provided from the peeling roller to the entrance of the tenter. As the adhering method, a method of applying an organic solvent liquid, an organic solvent Examples thereof include a method of spraying a gas, a method of spraying an organic solvent in a mist form, and a method of adjusting the amount of the organic solvent to be attached depending on the size of the curl. Further, the organic solvent is applied to such an extent that the additive does not elute, and the non-driving roller is used as a back roller on the entire non-driving roller (conveying roller) side of the non-driving roller (contact roller) with which the supporting body surface comes into contact. A coating roller (which may be a peeling roller) for coating is applied.

  Furthermore, when spraying organic solvent gas over the entire air surface of the film or spraying the organic solvent in the form of a mist, the concentration of the organic solvent should be within a range that does not cause an explosion, and after attaching the organic solvent, as much as possible Evaporate or exhaust excess gas quickly by suction. In addition, as the organic solvent, those having a solubility or swelling ability with respect to the solid electrolyte are used, but in order to adjust the curl degree, a solvent having no solubility or swelling ability with respect to the solid electrolyte is mixed. It is easier to obtain better results when used alone, and the mixing ratio is preferably 20/80 to 90/10 as a weight ratio, and is appropriately determined depending on the combination curl degree of each organic solvent. Moreover, in this case, it is effective by heating from the air surface side.

  The curl correcting means can be used without limitation as long as it can heat both ends, but means for correcting the ends with heated air on the roller, means for correcting by sandwiching the film from the front and back with a pair of heating rollers, It is a means to correct by indirectly heating with infrared rays or far infrared rays, etc. The heating air should be blown from the nozzle, pipe cross section or pipe with punch hole, the heating roller is narrow and only at both ends A roller such as a nip roller may be brought into contact. Moreover, the part to heat is less than 100 mm from the edge of the both ends of a film, More preferably, it is less than 50 mm. In this case, the heating temperature is preferably 50 ° C. or higher and 200 ° C. or lower, more preferably 80 ° C. or higher and 150 ° C. or lower. Further, in the case of the heating roller, the roller is preferably a metal roller, but a ceramic roller may be more preferable, and a method in which the ceramic roller is indirectly heated with infrared rays is also preferable.

  Incidentally, if the film is left as it is after heating, both ends of the film are soft, and curling may occur again. For this reason, it is preferable to cool only the heated portion as soon as possible after heating. The method for cooling is not particularly limited as long as it can be cooled. For example, a method of applying cooling air and a method of bringing a cooling roller into contact with each other are preferable methods. As a detailed condition, there is a method in which the cooling temperature is lower by 10 ° C. or less than the heating temperature. In addition, after peeling, there is also a method of correcting the curl by cutting the curl generated at both ends in the region where the residual solvent amount of the film is 50% by weight or less from the both side ends within 50 mm. The curl at both side ends is easily curled again and is easily rounded just by cutting, so it is preferable to cut the curl immediately before the entrance of the tenter or just before the driving roller.

  In order to prevent the antioxidant or plasticizer from adhering to the roller, the film having a small thickness and containing a relatively large amount of residual solvent has a roller diameter of, for example, less than 85 mm when transferred by a transfer roller after peeling. In such a small or thin roller, the roller is easily deformed or stretched by the force of the film pressed against the roller surface, but not only that, but the additive deposited and evaporated from the film adheres to the roller. The film is transferred to a film to make it dirty, or is pressed by an additive to easily form a recess. On the other hand, if the roller diameter is larger or larger than 300 mm, for example, if the roller is weak, the roller will not rotate properly and scratches will be applied to the film. Therefore, the thick roller is rotated in synchronization with the film transfer. In this case, it is necessary to increase the tension, and as a result, dirt and dents are generated. Accordingly, the diameter of the roller is preferably 85 to 300 mm, and particularly preferably 100 to 200 mm. In a more preferred embodiment, when a plurality of additives are used, the temperature is set to a temperature higher than the highest melting point.

  To stretch or shrink the film in the longitudinal direction using a tenter, the simultaneous biaxial stretching machine is used to expand or contract the interval in the transport direction of the clips and pins in the transport direction (longitudinal direction). be able to. At this time, it is preferable to drive the clip portion by the linear drive method because it can be smoothly stretched and the risk of breakage and the like can be reduced. Moreover, as a method of extending | stretching to a vertical direction, the method of giving a circumferential speed difference to several rolls, and extending | stretching to a vertical direction using a roll circumferential speed difference among them can also be used. In addition, these extending | stretching methods can also be used combining, and extending | stretching processes may be divided into two or more steps like longitudinal stretching, lateral stretching, longitudinal stretching or longitudinal stretching, longitudinal stretching, etc.

  It is preferable to provide a step of preheating the film with a heating device before stretching since the film can be prevented from changing its shape due to a temperature change. In addition, you may heat after extending | stretching. In this case, for example, in the case of using a blower for sending dry air as the heating device, the heating temperature of the dry air is set to a temperature that is 20 ° C. lower than the glass transition temperature of the solid electrolyte film by 10 ° C. It is preferable. The heating time is preferably 1 second or more and 180 seconds or less.

  When stretching the film, it is carried out at room temperature or under heating conditions. The heating temperature is preferably not higher than the glass transition temperature of the film. The film may be stretched uniaxially or biaxially. The film can be stretched by a treatment during drying, and is particularly effective when the solvent remains. For example, the film is stretched by adjusting the speed of the film transport roller so that the film winding speed is higher than the film peeling speed. The film can also be stretched by conveying the film while holding it with a tenter and gradually widening the tenter. After the film is dried, it can be stretched using a stretching machine such as a tenter (preferably uniaxial stretching using a long stretching machine). The draw ratio of the film (ratio of increase due to stretching relative to the original length) is preferably 0.5 to 300%, more preferably 1 to 200%, and particularly 1 to 100%. Is preferred.

  The stretching speed is preferably 5% / min to 1000% / min, and more preferably 10% / min to 500% / min. Heating during stretching is preferably performed by a heat roller or / and a radiant heat source (such as an IR heater) or warm air. Moreover, you may provide a thermostat in order to improve the uniformity of temperature. When performing uniaxial stretching by roller stretching, it is preferable that L / W which is a ratio of the distance (L) between rollers and the film width (W) of this phase difference plate is 2.0-5.0.

In addition, it is preferable that the difference in tension acting on the film along the conveying direction before and after the tenter is 8 N / mm ² or less because a thin film can be obtained.

In this embodiment, the crossing part and the tenter are provided to dry the film. Thus, when a transition part is provided and the film is heated at a temperature different from that of the tenter, the effect of preheating the film is obtained, so that the temperature of the film does not rise rapidly. Thereby, the effect which suppresses the shape change of a film and deterioration of a raw material polymer is acquired. Furthermore, after the stretching / drying step, it is preferable to perform a relaxation step of relaxing the film by an amount smaller than the stretching amount in the stretching / drying step, because even a thin film can be manufactured while suppressing shape change and the like. . In the case of performing the preheating step and stretching drying step using a drying means, the heating temperature T ₁ of the film by the drying means, and (glass transition temperature T _g -60 films) ° C. or higher, and the temperature in the relaxing step T ₂ is preferably set to (T ₁ -10) ° C. or lower. At this time, the stretch ratio of the film in the stretching and drying step is 0% to 30% in a ratio to the width of the film immediately before entering the stretching and drying step, and the stretch ratio of the film in the relaxation step is −10% to 10%. It is preferable to do.

  Also, in the stretching and drying process, in order to avoid the risk that the solvent evaporating from the film will adhere to the surface of the film to be dried and reduce its flatness, a gripping means incorporating a heating function should be used. Is preferred. Further, the tenter is preferably provided with a device for removing foreign substances generated at the contact portion between the gripping means such as a clip and the film, for example, a solvent once evaporated and condensed. Examples of this device include means that can blow a gas and blow off foreign matter, a brush, and the like.

  In addition, in order to improve the quality degradation due to tearing in the tenter and increase the productivity in order to obtain a film with better flatness, the arbitrary transport length of the tenter is set to Lt (m) in the clip. Where Lt (m) is the total length in the transport direction of the portion of the tenter clip having the same length as Lt that holds the film, and the ratio Ltt / Lt between Lt and Ltt is Lr. Preferably satisfies 1.0 ≦ Lr ≦ 1.99. As a more preferred embodiment, the portion holding the film is arranged without a gap when viewed from the width direction of the film.

  As a drying device used in the stretching and drying process, in a pin tenter using pins for gripping means, the inner pin density is increased to prevent film breakage, wrinkles and sagging, and conveyance failure. There is a method of reducing the density. In the pin tenter, in order to prevent foaming of the film itself and the film from adhering to the pin, the holding pins for gripping both ends of the film are cooled to below the foaming temperature of the film by a blow-out type cooler, and the film is There is also a method of cooling the pin immediately before biting to the gelation temperature of the dope in the duct type cooler + 15 ° C. or lower.

  Furthermore, in order to prevent the pin tenter from losing and to improve foreign matter, the pin structure is cooled in the pin tenter, and the surface temperature of the film in contact with the plug structure does not exceed the gel temperature of the film. There is also a solution casting method.

  In order to prevent wrinkles and sagging in the multistage tenter, there is a method in which a heating chamber and a cooling chamber are provided in the dryer of the multistage tenter and the left and right clip chains are cooled separately. The multistage tenter is a mode in which two or more tenters are provided, or a film is stretched in two or more times by the tenter.

  In addition, it is preferable to heat-treat the stretched film by providing a temperature gradient in the width direction of the film in the heat relaxation step after the stretching and drying step, so that unevenness of the film can be prevented. In order to prevent the occurrence of unevenness, there is a method in which the amount of residual solvent in the film is 2% to 10% by weight and stretched.

  Also, in order to suppress the curling due to the clip biting width, when the tenter clip biting width is D, the tenter is drawn to satisfy the condition of D ≦ {33 / (log drawing rate × log volatile content)}. Then, curling can be suppressed and the film can be easily conveyed after the stretching and drying step.

  In order to achieve both high-speed conveyance and stretching, there is also a method of using a pin in the first half and switching to a clip in the second half when conveying with a tenter.

  As another stretching method, a circumferential speed difference is applied to a plurality of rollers, and the film is stretched in the longitudinal direction using the circumferential speed difference between the rollers. Both ends of the film are fixed with clips or pins, and the clips or pins A method of extending the distance in the direction of travel and extending in the vertical direction, a method of extending in the horizontal direction and extending in the horizontal direction, a method of extending simultaneously in the vertical and horizontal directions and extending in both the vertical and horizontal directions, a method of combining these, etc. Can be mentioned. Further, in the case of the so-called tenter method, it is preferable to drive the clip portion by the linear drive method because smooth stretching can be performed and the risk of breakage or the like can be reduced.

  Furthermore, for the purpose of obtaining a film having little bleed-out where the additive oozes out or deposits on the surface of the film, no delamination phenomenon between layers, and good slipperiness, a resin, an additive and an organic solvent are used. Between the surface layer made of the dope B, and a dope B containing a resin, an additive, and an organic solvent containing no additive or less additive than the dope A. There is a method of co-casting both dopes on a support so that the sandwiched base layer is formed from dope A. In this method, after the dope is co-cast to form a cast film on the support, the organic solvent of the cast film is evaporated until it becomes peelable, and then the cast film is peeled off from the support as a film. Further, when the amount of residual solvent in the film is in the range of 3 wt% to 50 wt%, the film is stretched 1.1 times to 1.3 times in at least one axial direction. In this method, as a more preferable embodiment, after peeling the film from the support, the film is stretched at least 1.1 times to 3.0 times in the uniaxial direction at a drying temperature of 140 ° C to 200 ° C. And as an especially preferable aspect, it is extending | stretching a film 1.1 to 3.0 times at least in the uniaxial direction in the range whose residual solvent amount in a film is 3 weight%-50 weight%. In addition, the additive amount in the dope A is 1% by weight to 30% by weight with respect to the resin to be used, and the additive amount in the dope B is 0% by weight to 5% by weight with respect to the resin to be used. And the additive is preferably an antioxidant or a plasticizer.

  Furthermore, when the film is dried with a tenter equipped with an air supply duct as a drying device, in order to prevent foaming of the film, improve detachability, and prevent dust generation, dry air from the air supply duct is used as a film. There is a method of making the width of the air supply duct shorter than the width of the film so as not to hit the both end portions of the film, or providing a wind shielding plate inside the both end portions of the film.

  Furthermore, in the drying in the tenter, the preferable drying conditions according to the amount of the residual solvent are specifically the angle at which the blowout angle blows out until the residual solvent amount in the film reaches 4% by weight. When the wind speed distribution on the film surface, which is in the range of 30 ° to 150 ° with respect to the plane and located in the direction in which the dry gas blows out, is based on the upper limit value of the wind speed, the difference between the upper limit value and the lower limit value is calculated. The surface of the film of dry gas blown out from the blow type dryer when the blown film is dried by blowing dry gas within the upper limit value of 20% and the residual solvent amount in the film is 130 wt% to 70 wt% When the above wind speed is 0.5 m / second to 20 m / second, and the residual solvent amount is 4 wt% or more and less than 70 wt%, the dry gas wind speed is 0.5 m / sec to 40 m / sec. Blowing When the drying gas is blown out and the temperature distribution of the drying gas in the width direction of the web is based on the upper limit value of the gas temperature, the difference between the upper limit value and the lower limit value should be within 10% of the upper limit value. When the amount of residual solvent in the film is 4% by weight to 200% by weight, the air flow ratio q of the dry gas blown out from the blow-out port of the blow-type dryer located above and below the film to be conveyed is 0.2 ≦ q ≦ 1. And so on. Furthermore, as a preferable aspect, at least one kind of gas is used for the drying gas, and the average specific heat is 31.0 J / K · mol to 250 J / K · mol or less, the room temperature contained in the drying gas during drying. And the concentration of the liquid organic compound is dried with a drying gas having a saturated vapor pressure of 50% or less.

  In addition, when introducing a film into the tenter, there is a method having a sag suppressing device in the width direction of the film before the entrance of the tenter in order to improve the flatness deterioration and the instability caused by the sag of the film. As a more preferable aspect, the sag suppressing device is a rotating roller that rotates in the direction range of 2 ° to 60 ° in the width direction, has an air intake device above the film, and a blower that can blow air from under the film. And the like.

  A method of introducing a film peeled off from a support into a tenter with an angle with respect to the horizontal for the purpose of preventing deterioration of quality and sagging that hinders productivity.

  Further, in order to produce a film having stable physical properties, when the amount of residual solvent is 50 wt% to 12 wt% after being peeled off, a film width detecting means is provided for conveying the film while applying tension in the width direction of the film. A method of changing the position of the bending point by calculating the width of the film from the detection signal by detecting the width of the film and having a film holding means and two or more variable bending points is also mentioned.

  Furthermore, in the tenter, in order to stabilize the grip by gripping means such as a clip and prevent the film from being broken for a long period of time and to obtain a high quality film, both the left and right sides of the film near the entrance of the tenter A guide plate for preventing curling on both sides of the film is disposed at least below the upper and lower ends of the end portion, and the film contact surface of the guide plate is in contact with the film contact resin portion arranged in the film transport direction. It may be constituted by a metal part for use. As a more preferred embodiment, the film contact resin portion on the film facing surface of the guide plate is disposed on the upstream side in the film transport direction, and the film contact metal portion is disposed on the downstream side, the film contact resin portion of the guide plate And the step (including the inclination) between the metal parts for film contact is within 500 μm, and the distance between the resin part for film contact of the guide plate and the film of the metal part for film contact in the width direction is 2 mm, respectively. It is -150mm, More preferably, it is 5mm -120mm.

  In addition, the resin part for film contact of the guide plate is provided on the metal guide substrate by surface resin processing or resin coating, the resin part for film contact of the guide plate is made of a single resin, the left and right side edges of the film The distance between the film facing surfaces of the guide plates arranged above and below in the part is 3 mm to 30 mm, and the distance between the film facing surfaces of the upper and lower guide plates at the left and right side edges of the film is In the width direction of the film and inward, it is enlarged at a rate of 2 mm or more per 100 mm width, and the upper and lower guide plates have a length of 10 mm to 300 mm at the left and right side edges of the film, respectively. And the upper and lower guide plates are arranged so as to be displaced forward and backward along the film transport direction, and between the upper and lower guide plates. The distance of deviation is -200 mm to +200 mm, the film facing surface of the upper guide plate is made of resin or metal only, and the film contact resin portion of the guide plate is made of Teflon (registered trademark). The film contact metal part is made of stainless steel, and the surface roughness of the film facing surface of the guide plate or the resin part for film contact and / or the metal part for film contact provided on the guide plate is 3 μm or less. And the like. The upper and lower guide plates for preventing film side edge curl generation are preferably located between the peeling side end of the support and the tenter inlet, and more preferably installed near the tenter inlet.

  Furthermore, in order to prevent cutting and unevenness of the film that occurs during drying in the tenter, after peeling, when the residual solvent amount of the film is 50 wt% to 12 wt%, the film is stretched and dried by a width stretching apparatus. There is a method of applying a pressure of 0.2 kPa to 10 kPa from both sides of the film with a pressurizing device when the residual solvent amount of the film is 10% by weight or less. As a more preferable aspect, when a nip roller is used as a method for finishing the application of tension when the residual solvent amount is 4% by weight or more and applying pressure from both sides of the film, about 1 to 8 pairs of nip rollers are used. The temperature when pressurizing is preferably 100 ° C to 200 ° C.

  Also, as a method of reducing vertical and horizontal dimensional fluctuations during storage under high temperature and high humidity conditions, in a method for producing a film in which a solid electrolyte solution is cast on a support and continuously peeled and dried. The drying shrinkage rate is 0 ≦ dry shrinkage rate (%) ≦ 0.1 × residual solvent amount (% by weight) when peeling off. Furthermore, as a preferred embodiment, when the residual solvent amount of the solid electrolyte film after peeling is in the range of 40% by weight to 100% by weight, at least the residual solvent amount is set to 30 while gripping both side ends of the film by tenter conveyance. The amount of residual solvent at the tenter inlet of the film after peeling is 40% to 100% by weight, the amount of residual solvent at the outlet is 4% to 20% by weight, For example, the tension of the film during conveyance increases from the entrance to the exit of the tenter, the tension for conveying the film by the tenter conveyance and the tension in the width direction of the film are substantially equal.

  In addition, as a method of extending | stretching the film formed by casting, the method of extending | stretching on heating conditions and the method of extending | stretching on solvent containing conditions are mentioned. When stretching under heating conditions, it is preferable to stretch at a temperature below the glass transition point of the resin. On the other hand, when stretching a cast film under solvent-impregnated conditions, it is once dried. It is possible to stretch the film by bringing the film into contact with the solvent again to impregnate the solvent.

  In place of the above-described method for forming a solid electrolyte into a film, a film in which the solid electrolyte enters the pores is manufactured by holding the solid electrolyte in the pores of a so-called porous substrate in which a plurality of pores are formed. However, a solid electrolyte film different from the above embodiment can be manufactured. As a method for producing such a solid electrolyte film, a method in which a sol-gel reaction solution containing a solid electrolyte is applied onto a porous substrate and the solid electrolyte is put into pores, and the porous substrate includes a solid electrolyte. There is a method of immersing in a sol-gel reaction solution to fill the solid electrolyte in the pores. Preferable examples of the porous substrate include porous polypropylene, porous polytetrafluoroethylene, porous cross-linked heat-resistant polyethylene, and porous polyimide. Moreover, a solid electrolyte film can also be formed by processing a solid electrolyte into a fiber shape, filling voids in the fiber with other polymer compounds, etc., and forming the film using the fiber. In this case, examples of the other polymer compound for filling the void include the substances mentioned as additives in the present specification.

  The solid electrolyte film of the present invention can be suitably used as a proton conductive membrane for a fuel cell, in particular, a direct methanol fuel cell, and also used as a solid electrolyte film sandwiched between two electrodes of a fuel cell. Can do. Furthermore, as electrolytes, display elements, electrochemical sensors, signal transmission media, capacitors, electrodialysis, electrolytic membranes for electrolysis, gel actuators, salt electrolytic membranes, proton exchange resins in various batteries (redox flow batteries, lithium batteries, etc.) The solid electrolyte film of the present invention can be used.

(Fuel cell)
Hereinafter, an example in which the solid electrolyte film is used for an electrode membrane composite (hereinafter referred to as MEA) and an example in which the electrode membrane composite is used for a fuel cell will be described. However, the modes of the MEA and the fuel cell shown here are examples of the present invention, and the present invention is not limited thereto. FIG. 4 is a schematic cross-sectional view of the MEA. The MEA 131 includes a film 62 and an anode electrode 132 and a cathode electrode 133 that are opposed to each other with the film 62 interposed therebetween.

  The anode electrode 132 has a porous conductive sheet 132 a and a catalyst layer 132 b in contact with the film 62, and the cathode electrode 133 has a porous conductive sheet 133 a and a catalyst layer 133 b in contact with the film 62. Examples of the porous conductive sheets 132a and 133a include carbon paper. The catalyst layers 132b and 133b are made of a dispersion in which carbon particles carrying a catalyst metal such as platinum particles are dispersed in a proton conductive material. Examples of the carbon particles include ketjen black, acetylene black, and carbon nanotube. Examples of the proton conductive material include Nafion (registered trademark).

As the manufacturing method of the MEA 131, the following four methods are preferable.
(1) Proton conductive material coating method: A catalyst paste (ink) containing active metal-carrying carbon, proton conductive material, and solvent is directly applied to both surfaces of the film 62, and the porous conductive sheets 132a and 133a are applied to the (heat) coating layer. A MEA having a five-layer structure is manufactured by pressure bonding.
(2) Porous conductive sheet coating method: After a liquid containing the material of the catalyst layers 132b and 133b, for example, a catalyst paste, is applied to the surfaces of the porous conductive sheets 132a and 133a to form the catalyst layers 132b and 133b. The film 62 is pressure-bonded to produce a MEA 131 having a five-layer structure.
(3) Decal method: After a catalyst paste is applied on PTFE to form catalyst layers 132b and 133b, only the catalyst layers 132b and 133b are formed on the film 62 to form a three-layer structure. The sheets 132a and 133a are pressure-bonded to produce a MEA 131 having a five-layer structure.
(4) Post-catalyst loading method: An ink in which a platinum unsupported carbon material is mixed with a proton conductive material is applied and formed on the film 62, the porous conductive sheets 132a, 133a or PTFE, and then the film is applied to a liquid containing platinum ions. 62 is impregnated, and platinum particles are reduced and deposited in the film to form the catalyst layers 132b and 133b. After the formation of the catalyst layers 132b and 133b, the MEA 131 is produced by the above methods (1) to (3).

  However, the method of making the MEA is not limited to the above method, and various known methods can be applied. For example, in addition to the above methods (1) to (4), there are the following methods. A coating solution containing the materials of the catalyst layers 132b and 133b is prepared in advance, and this coating solution is applied to a support and dried. The support on which the catalyst layers 132b and 133b are formed is pressure-bonded on the both sides of the film 62 so that the catalyst layers 132b and 133b are in contact with the film 62, respectively. And after peeling a support body, the film 62 in which the catalyst layers 132b and 133b were formed in both surfaces is pinched | interposed with the porous conductive sheets 132a and 133a. And MEA can be manufactured by closely contacting the porous conductive sheets 132a and 133a and the catalyst layers 132b and 133b.

  FIG. 5 is a schematic view of a fuel cell. The fuel cell 141 includes an MEA 131, a pair of separators 142 and 143 that sandwich the MEA 131, a current collector 146 made of a stainless net attached to the separators 142 and 143, and a packing 147. An anode pole side opening 151 is provided in the anode pole side separator 142, and a cathode pole side opening 152 is provided in the cathode pole side separator 143. Gas fuel such as hydrogen and alcohols (such as methanol) or liquid fuel such as an alcohol aqueous solution is supplied from the anode electrode side opening 151, and oxidant gas such as oxygen gas and air is supplied from the cathode electrode side opening 152. Is supplied.

  A catalyst in which active metal particles such as platinum are supported on a carbon material is used for the anode electrode 132 and the cathode electrode 133. Commonly used active metal particle sizes are in the range of 2 to 10 nm. However, the smaller the particle size, the greater the surface area per unit weight, which increases the activity and is advantageous. However, if it is too small, it is difficult to disperse without agglomeration, so about 2 nm is said to be the small limit. .

  The active polarization in the hydrogen-oxygen fuel cell is larger in the cathode electrode, that is, the air electrode than in the anode electrode, that is, the hydrogen electrode. This is because the rate of the cathode electrode reaction, that is, the oxygen reduction reaction, is slower than that of the anode electrode. For the purpose of improving the activity of the oxygen electrode, various platinum-based binary metals such as Pt—Cr, Pt—Ni, Pt—Co, Pt—Cu, and Pt—Fe can be used. In a direct methanol fuel cell using a methanol aqueous solution as the anode fuel, in order to suppress catalyst poisoning by CO generated during the oxidation process of methanol, Pt—Ru, Pt—Fe, Pt—Ni, Pt—Co, and Pt—Mo are used. Pt-Ru-Mo, Pt-Ru-W, Pt-Ru-Co, Pt-Ru-Fe, Pt-Ru-Ni, Pt-Ru-Cu, Pt-Ru-Sn, etc. A platinum group ternary metal such as Pt—Ru—Au can be used. As the carbon material for supporting the active metal, acetylene black, Vulcan XC-72, ketjen black, carbon nanohorn (CNH), and carbon nanotube (CNT) are preferably used.

The catalyst layers 132b and 133b are generated by (1) transporting the fuel to the active metal, (2) providing a field for the oxidation (anode electrode) and reduction (cathode electrode) reaction of the fuel, and (3) oxidation / reduction. And (4) transports protons generated by the reaction to the solid electrolyte, that is, the film 62. For (1), the catalyst layers 132b and 133b are made porous so that liquid and gaseous fuel can permeate deeply. For (2), the active metal catalyst supported on the carbon material is responsible, and (3) is also responsible for the carbon material. In order to fulfill the function (4), a proton conductive material is mixed in the catalyst layers 132b and 133b. The proton conductive material of the catalyst layer is not limited as long as it is a solid having a proton donating group, but is represented by a polymer compound having an acid residue used for the film 62, for example, Nafion (registered trademark). Preferable examples include sulfonated products of heat-resistant aromatic polymers such as perfluorosulfonic acid, side chain phosphate group poly (meth) acrylate, sulfonated polyetheretherketone, and sulfonated polybenzimidazole. When the solid electrolyte used as the material of the film 62 is used for the catalyst layers 132b and 133b, the catalyst layers 132b and 133b and the film 62 are the same type of material, so that the electrochemical adhesion between the solid electrolyte and the catalyst layer is increased. This is more advantageous in terms of ion conduction. It is suitable from a viewpoint of battery output and economical efficiency to make the usage-amount of an active metal into the range of 0.03-10 mg / cm < ² >. The amount of the carbon material supporting the active metal is preferably 1 to 10 times the weight of the active metal. The amount of the proton conductive material is preferably 0.1 to 0.7 times the weight of the active metal-carrying carbon.

  The catalyst layers 132b and 133b are also referred to as an electrode base material, a permeable layer, or a backing material, and play a role of preventing current collection and deterioration of gas permeation and accumulation of water. Usually, carbon paper or carbon cloth can be used, and polytetrafluoroethylene (PTFE) treated for water repellency can be used.

MEA is incorporated into a battery, preferably having an area resistance value of 3Omucm ² below by the AC impedance method in a state filled with fuel, more preferably those of 1 .OMEGA.cm ² or less, and most preferably those 0.5Omucm ² below. The area resistance value is obtained from the product of the actually measured resistance value and the area of the sample.

  What can be used as a fuel of a fuel cell will be described. Examples of the anode fuel include hydrogen, alcohols (such as methanol, isopropanol, and ethylene glycol), ethers (such as dimethyl ether, dimethoxymethane, and trimethoxymethane), formic acid, borohydride complex, and ascorbic acid. Examples of the cathode fuel include oxygen (including oxygen in the atmosphere) and hydrogen peroxide.

In a direct methanol fuel cell, a methanol aqueous solution having a methanol concentration of 3 wt% to 64 wt% is used as an anode fuel. According to the anode reaction formula (CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻ ), 1 mol of water is required for 1 mol of methanol, and the methanol concentration at this time corresponds to 64% by weight. The higher the methanol concentration, there is an advantage that the weight and volume of the battery including the fuel tank with the same energy capacity can be reduced. However, the higher the methanol concentration, the more so-called crossover phenomenon that methanol permeates the solid electrolyte and reacts with oxygen on the cathode side to lower the voltage, and the output tends to decrease. Therefore, the optimum concentration is determined by the methanol permeability of the solid electrolyte used. The cathode reaction formula of the direct methanol fuel cell is (3/2) O ₂ + 6H ⁺ + 6e ⁻ → H ₂ O, and oxygen (usually oxygen in the air) is used as the fuel.

  As a method of supplying the anode fuel and the cathode fuel to the respective catalyst layers 132b and 133b, (1) a method of forcibly feeding using an auxiliary device such as a pump (active type), and (2) an auxiliary device There are two methods that are not used, for example, a passive type in which the fuel is exposed to the atmosphere by exposing the catalyst layer to the atmosphere due to capillary action or natural fall when the fuel is a liquid, and ( It is also possible to combine 1) and (2). (1) has the advantage that by extracting the water produced on the cathode side, high-concentration methanol can be used as the fuel, and high output can be achieved by air supply, but a fuel supply system is provided. Therefore, there is a drawback that miniaturization is difficult. Although (2) has the advantage that it can be downsized, it has a drawback that the fuel supply is likely to be rate-limiting and it is difficult to produce a high output.

  Since the single cell voltage of the fuel cell is generally 1 V or less, the single cells are used by stacking in series according to the required voltage of the load. As the stacking method, “planar stacking” in which single cells are arranged on a plane and “bipolar stacking” in which single cells are stacked via separators having fuel flow paths formed on both sides thereof are used. The former is suitable for a small fuel cell because the cathode electrode (air electrode) comes out on the surface, so that air can be easily taken in and can be made thin. In addition to this, a method of applying MEMS technology, performing fine processing on a silicon wafer, and stacking has been proposed.

  Fuel cells are considered for various uses such as for automobiles, homes, and portable devices.In particular, direct methanol fuel cells are advantageous in that they can be reduced in size and weight and do not require charging. It is expected to be used as an energy source for various portable devices and portable devices. For example, mobile devices that can be preferably applied include mobile phones, mobile laptop computers, electronic still cameras, PDAs, video cameras, portable game machines, mobile servers, wearable personal computers, mobile displays, and the like. Examples of portable devices that can be preferably applied include portable generators, outdoor lighting devices, flashlights, and electric (assist) bicycles. It can also be preferably used as a power source for industrial or household robots or other toys. Furthermore, it is also useful as a power source for charging secondary batteries mounted on these devices.

  Next, examples of the present invention will be described. In each of the following examples, details will be described in Example 1, and only the conditions different from Example 1 will be described for Examples 2 to 8. In addition, Examples 1-3, 7, and 8 are examples of the embodiment of this invention, and Examples 4-6 are comparative experiments with respect to Examples 1-3.

The raw material A was flash-concentrated with a flash device 26 and dried. The dried raw material A and the solvent were mixed in the following composition, and the solid content of the raw material A was dissolved in the solvent to produce a 20 wt% solid electrolyte dope 24. This dope 24 is referred to as dope A in the following description. The raw material A is 20% Nafion (registered trademark) Dispersion Solution DE2020 (manufactured by DuPont, USA).
-Raw material A after drying; 100 parts by weight-Solvent: 400 parts by weight of perfluorohexane

[Production of solid electrolyte film]
Casting from the casting die 81 to the casting band 82 running on the dope A to form a casting film 24a, and drying air of 30 to 50 ° C. is blown by the first to third air ducts 91 to 93 to solidify the raw material A The cast membrane was dried until the residual solvent amount was 30 wt% with respect to the solid electrolyte. When the casting film 24 a had self-supporting properties, the casting film 24 a was peeled off as the film 62 from the casting band 82, and then the film 62 was fed into the tenter 64. In the tenter 64, while holding both sides of the film 62 with the clip 64a and transporting, the drying air was sent out from the air supply duct 64b to dry the film 62.

  As the clip 64a, a clip in which a flow path serving as a passage of the heat transfer medium is formed is used. Then, a heat transfer medium at 20 ° C. was supplied to the flow path to cool the clip 64a. The clip 64a was conveyed by a chain, and the speed fluctuation of the sprocket was 0.5% or less. Further, the interior of the tenter 64 was divided into three sections, and the drying temperature of each section was set to 40 ° C., 50 ° C., and 50 ° C. from the upstream side. The gas composition of the drying air was set to a saturated gas concentration at −10 ° C. In the tenter 64, the film 62 was stretched in the width direction while being transported. At this time, when the width of the film 62 before stretching was 100%, the film 62 after stretching was stretched so that the width was 150%.

  The stretching ratio inside the tenter 64 is such that the difference between the stretching ratios at any two points 10 mm or more away from the biting start position by the clip 64a is 10% or less and any two points 20 mm apart. The difference in rate was 5% or less. The ratio of the length from the clip grip start position to the clip release position with respect to the length from the entrance to the exit of the tenter 64 was 90%. Further, the solvent evaporated inside the tenter 64 was condensed and liquefied at a temperature of −10 ° C. and recovered. The outlet temperature of a condenser (not shown) provided for condensation recovery was set to -8 ° C. The condensed solvent was reused for dope production after the water content was adjusted to 0.5 wt% or less.

The film 62 was detached from the clip 64 a at the outlet of the tenter 64, and both end portions gripped by the clip 64 a were cut and removed by an ear clip device 67 provided downstream of the tenter 64. At this time, as the edge-cutting device 67, both end portions of the film 62 were cut by 40 mm from both sides using an NT type cutter. The cut ears were fed into a crusher 103 by a cutter table (not shown) and crushed into chips of about 80 mm ² on average. This chip was again used as a raw material for dope production together with solid electrolyte flakes as a raw material for dope preparation. The air in the tenter 64 was replaced with nitrogen gas, and the oxygen concentration in the dry atmosphere in the tenter 64 was kept at 5 vol%.

  The film 62 from which the end portion was removed was sent to the drying chamber 69 and dried at 50 to 70 ° C. while being conveyed by a plurality of rollers 68. A solid electrolyte film 62 having a residual solvent amount of less than 3% by weight was obtained.

  The manufactured film 62 was subjected to the following evaluations. The evaluation results are shown in Table 1. The numbers of the evaluation items in Table 1 correspond to the numbers given to the following evaluation items.

1. Thickness The thickness of the film 62 was continuously measured using an electronic micrometer manufactured by Anritsu Electric Co., Ltd. at a speed of 600 mm / min. Data obtained by the measurement was recorded on the chart paper at a scale of 1/20 and a chart speed of 30 mm / min. And after measuring about a data curve with a ruler, the average value (unit; micrometer) of thickness was calculated | required based on the measured value.

2. Elasticity measurement Stress (MD1) in the transport direction of film 62 at 0.5% elongation in an atmosphere of 23 ° C. and humidity of 70% RH at a tensile rate of 10% / min, using Toyo Baldwin Universal Tensile Tester STM T50BP ) And stress in the width direction (referred to as TD1), and these were obtained as the elastic modulus (GPa) of the film 62, respectively.

3. Tensile strength measurement Film 62 cut to a size of 15 × 250 mm was used as a sample, and after conditioning for 2 hours at a temperature of 23 ° C. and a humidity of 65% RH, this sample was subjected to Tensilon tensile tester (Orientec Co., Ltd. RTA-100), in accordance with ISO 1184-1983, the tensile strength when the length of the initial film is 100 mm and the tensile speed is 200 ± 5 mm / min is calculated from the stress and elongation at the initial stage of tension. Of tensile strength (MPa). In addition, the tensile strength was obtained by setting the value in the transport direction of the sample as MD2 (MPa) and the value in the width direction as TD2 (MPa).

4). Ion conductivity measurement About the obtained solid electrolyte film 62, ten measurement locations were selected every 1 m along the longitudinal direction. Ten of them were punched out as a circular sample having a diameter of 13 mm. Each sample was sandwiched between two stainless steel plates, and ion conductivity was measured by an AC impedance method using Solartron 1470 and 1255B. The measurement was performed under the conditions of 80 ° C. and relative humidity of 95%. As shown in Table 1, the ionic conductivity is shown as an AC impedance value (unit: S / cm).

5. Output density of fuel cell 141 A fuel cell 141 was produced using the film 62, and the output of the fuel cell 141 was measured. The production method of the fuel cell 141 and the measurement method of the power density are as follows.

(1) Preparation of catalyst sheet A used as catalyst layers 132b and 133b 2 g of platinum-supporting carbon and 15 g of a solid electrolyte (5% DMF solution) were mixed and dispersed for 30 minutes with an ultrasonic disperser. The average particle size of the dispersion was about 500 nm. The obtained dispersion was applied onto a carbon paper having a thickness of 350 μm and dried, and then the carbon paper was punched into a circle having a diameter of 9 mm to prepare a catalyst sheet A. The platinum-supporting carbon was obtained by supporting 50% by weight of platinum on Vulcan XC72, and the solid electrolyte was the same as that for manufacturing the film 62.

(2) Production of MEA 131 Catalyst sheet A was laminated on both surfaces of solid electrolyte film 62 so that the coating film was in contact with film 62, and thermocompression bonded at 80 ° C. and 3 MPa for 2 minutes to produce MEA.

(3) Output Density of Fuel Cell 141 The MEA obtained in (2) was set in the fuel cell shown in FIG. 5, and a 15 wt% aqueous methanol solution was injected into the opening 151 on the anode electrode side. At this time, the opening 152 on the cathode electrode side was in contact with the atmosphere. The anode electrode 132 and the cathode electrode 133 were connected by a multichannel battery evaluation system (Solartron 1470), and the output density (unit: W / cm ² ) was measured.

The raw material B and the solvent were mixed in the following composition, and the raw material B was dissolved in the solvent to produce a 20 wt% solid electrolyte dope 24. This dope 24 is referred to as dope B in the following description. The raw material B is sulfonated polyacrylonitrile butadiene styrene having a sulfonation degree of 35%.
-Raw material B; 100 parts by weight-Solvent: 400 parts by weight of N, N-dimethylformamide

In addition, the raw material B was manufactured with the following synthesis methods.
(1) Synthesis of 4- (4- (4-pentylcyclohexyl) phenoxymethyl) styrene After reacting substances having the following composition at 100 ° C. for 7 hours, the resulting reaction solution was cooled to room temperature, Water was added for crystallization. After filtering the crystallization solution, the obtained filtrate was washed with an aqueous solution of water / acetonitrile = 1/1 and air-dried to obtain 4- (4- (4-pentylcyclohexyl) phenoxymethyl) styrene.
-14 parts by weight of 4- (4-pentylcyclohexyl) phenol-9 parts by weight of 4-chloromethylstyrene-11 parts by weight of potassium carbonate-66 parts by weight of N, N-dimethylformamide

(2) Synthesis of graft copolymer A mixture having the following composition was heated to 60 ° C.
-Polybutadiene latex 100 parts-Potassium rosinate 0.83 parts-Dextrose 0.50 parts by weight-Sodium pyrophosphate 0.17 parts by weight-Ferrous sulfate 0.08 parts by weight-Water 250 parts by weight

Thereafter, a mixture having the following composition was added dropwise over 60 minutes to the above mixture to carry out a polymerization reaction.
Acrylonitrile 21 parts by weight 4- (4-4-pentylcyclohexyl) phenoxymethyl) styrene 62 parts by weight t-dodecylthiol 0.5 parts by weight Cumene hydroperoxide 3.0 parts by weight

  After completion of the dropwise addition, 0.2 parts by weight of cumene hydroperoxide was added thereto, followed by cooling for 1 hour to obtain a latex. The obtained latex was put in 60 ° C. and 1% sulfuric acid, and heated to 90 ° C. for coagulation. This was thoroughly washed with water and dried to obtain a graft copolymer.

(3) Synthesis of raw material B by sulfonation of graft copolymer 100 parts by weight of the graft copolymer obtained in (2) was dissolved in 1300 parts by weight of methylene chloride, and the resulting solution was kept at 0 ° C. or lower. While, 13 parts by weight of concentrated sulfuric acid was slowly added thereto. This was stirred for 6 hours to cause precipitation. After removing the solvent, the precipitate was dried to obtain sulfonated polyacrylonitrile butadiene styrene as raw material B. The introduction rate of sulfonic acid groups by titration was 35%.

[Production of solid electrolyte film]
The temperature of the wind from the 1st-3rd ventilation ducts 91-93 was 80-120 degreeC. The temperature of the drying air in the tenter 64 was 140 ° C. The film 62 from which the side edge portion was removed by the edge-cutting device 67 was dried in a drying chamber 62 at a temperature of 140 to 160 ° C. to obtain a solid electrolyte film 62 having a residual solvent amount of less than 3% by weight. In the tenter 64, the inside of the tenter 64 was divided into three parts, and the drying conditions were the same as those in Example 1 except that the drying temperature was set to 120 ° C, 130 ° C, and 140 ° C from the upstream side. The evaluation results on the obtained film 62 are shown in Table 1.

The raw material C and the solvent were mixed in the following composition, and the raw material C was dissolved in the solvent to produce a 20 wt% solid electrolyte dope 24. This dope 24 is referred to as dope C in the following description. The raw material C is a sulfopropylated polyethersulfone having a sulfonation degree of 35%, and was synthesized based on the synthesis method described in JP-A No. 2002-110174.
-Raw material C; 100 parts by weight-Solvent: N-methylpyrrolidone 400 parts by weight

[Production of solid electrolyte film]
The temperature of the wind from the 1st-3rd ventilation ducts 91-93 was 80-140 degreeC. The temperature of the drying air in the tenter 64 was 160 ° C. The film 62 from which the side edge portion was removed by the edge cutting device 67 was dried in a drying chamber 62 at a temperature of 160 to 180 ° C. to obtain a solid electrolyte film 62 having a residual solvent amount of less than 3% by weight. In the tenter 64, the inside of the tenter 64 was divided into three parts, and the drying conditions were the same as those in Example 1 except that the drying temperature was set to 140 ° C, 150 ° C, and 160 ° C from the upstream side. The evaluation results on the obtained film 62 are shown in Table 1.

[Production of solid electrolyte film]
In Example 1, when the width of the film 62 before stretching inside the tenter 64 is 100%, the film 62 after stretching is the same as in Example 1 except that the film 62 is stretched so that the width becomes 103%. Film 62 was made using the dope and conditions. The evaluation results on the obtained film 62 are shown in Table 1.

[Production of solid electrolyte film]
In Example 2, when the width of the film 62 before stretching inside the tenter 64 is 100%, it is the same as in Example 1 except that the film 62 after stretching is stretched so that the width becomes 103%. Film 62 was made using the dope and conditions. The evaluation results on the obtained film 62 are shown in Table 1.

  In Example 3, when the width of the film 62 before stretching inside the tenter 64 is 100%, it is the same as in Example 1 except that the film 62 after stretching is stretched so that the width becomes 103%. Film 62 was made using the dope and conditions. The evaluation results on the obtained film 62 are shown in Table 1.

The compound shown in Chemical formula 3 was used as a solid electrolyte. However, protonation for obtaining the compound of Chemical Formula 3, that is, acid treatment was carried out in the film production process as follows, not before the dope production. An unprotonated product of Chemical Formula 3, that is, a solid electrolyte precursor, is used as a raw material D. The raw material D was dissolved in a solvent and used for casting. The method for making the dope is the same as the method for making the dope 24 in the first embodiment. The solvent is a mixture of the solvent component 1 that is a good solvent for the raw material D and the solvent component 2 that is a poor solvent for the raw material D. In Example 7, X in chemical formula 3 is Na, Y is SO ₂ , Z is chemical formula (I), n is 0.33, m is 0.67, number average molecular weight Mn is 61000, and quantity average. The molecular weight Mw is 159000.
-Raw material D; 100 parts by weight-Solvent component 1; 256 parts by weight of dimethyl sulfoxide-Solvent component 2; 171 parts by weight of methanol

  Since the dope is cast and peeled off from the casting band 82 is made of the raw material D, it is called a precursor film. The precursor film from which both side ends were removed by the edge-cutting device 67 through the same conditions as in Example 1 was protonated by acid treatment and then subjected to a washing step. The acid treatment is a step of bringing the precursor film into contact with an acid aqueous solution. By this acid treatment, the structure of the precursor becomes a structure represented by the general formula of Chemical Formula 3, that is, a solid electrolyte. The contact was performed by a method in which an aqueous acid solution was continuously supplied to a liquid tank and a film made of a solid electrolyte was immersed in this aqueous solution. Washing after the acid treatment was carried out with water. The film 62 after the cleaning process was sent to the drying chamber 69. The evaluation results for the obtained film 62 are shown in Table 1.

The compound shown in Chemical formula 3 and different from Example 7 was used as the solid electrolyte. However, protonation for obtaining the compound of Chemical Formula 3 was carried out in the film production process, not before the dope production, as in Example 7. A precursor used as a dope component is referred to as a raw material E. The solvent is a mixture of solvent component 1 and solvent component 2 as shown below. The solvent component 1 is a good solvent for the raw material E, and the solvent component 2 is a poor solvent for the raw material E. In Example 8, X in Chemical Formula 3 is Na, Y is SO ₂ , Z is Chemical Formulas (I) and (II), n is 0.33, m is 0.67, and the number average molecular weight Mn is 68,000 and the weight average molecular weight Mw are 200000. In Chemical Formula 4, (I) is 0.7 mol% and (II) is 0.3 mol%. The other conditions are the same as in Example 7.
-Raw material E; 100 parts by weight-Solvent component 1; 200 parts by weight of dimethyl sulfoxide-Solvent component 2; 135 parts by weight of methanol

  The following evaluation was implemented about the film 62 obtained in Examples 1-8. The evaluation results are shown in Table 1. The numbers of the evaluation items in Table 1 correspond to the numbers given to the following evaluation items.

  From the results of the above examples, according to the present invention, by adjusting the stretching by the tenter, a solid electrolyte film having excellent mechanical strength and flatness and high proton conductivity which is an indicator of proton conductivity is produced. You can see that it is possible. Moreover, it turns out that the obtained solid electrolyte film can be used conveniently as a solid electrolyte layer of the fuel cell which implement | achieves high output density.

It is the schematic of dope manufacturing equipment. It is the schematic of a film manufacturing equipment. It is the schematic of an example of the tenter used by this embodiment. It is sectional drawing of an electrode membrane composite. It is sectional drawing of a fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Dope manufacturing equipment 24 Dope 24a Casting film 33 Film manufacturing equipment 62 Solid electrolyte film (film)
64 Tenter 64a Clip 64b Air supply duct 69 Drying chamber 131 Electrode membrane composite (MEA)
132 Anode electrode 133 Cathode electrode 141 Fuel cell 146 Current collector

Claims (15)

A casting film forming step of casting a dope containing a solid electrolyte and an organic solvent from a casting die onto a support to form a casting film;
A stripping step of stripping the cast film as a film from the support;
A drying step of drying the film to form a solid electrolyte film,
In the drying step, after the both end portions are gripped by the gripping means that moves in the transport path of the film, the film is stretched in the width direction while being transported by the movement of the gripping means, and the drying means The manufacturing method of the solid electrolyte film characterized by including the dry extending | stretching drying process which dries a film.   The method for producing a solid electrolyte film according to claim 1, wherein drying air is blown onto the film by the drying means having an air outlet.   While the distance between the gripping means facing each other at both end portions of the film is changed to change the length in the width direction of the film, the temperature of the drying air is made substantially constant. The method for producing a solid electrolyte film according to claim 2. When the length between the gripping positions of the gripping means when the film is gripped by the gripping means is defined as a gripping width,
A first step of holding the grip width constant, a second step of expanding the grip width, a third step of reducing the grip width, and a fourth step of holding the grip width constant after the third step. The method for producing a solid electrolyte film according to any one of claims 1 to 3, further comprising a step. The gripping means in the first step is set to A (mm), the maximum value of the gripping width in the second step is set to B (mm), and after the gripping width is reduced in the third step, the gripping means When the width of the film when the film is detached from C (mm),
The method for producing a solid electrolyte film according to claim 4, wherein the A, B, and C satisfy a condition of 1 <100 × (BC) / A <15.   6. The method for producing a solid electrolyte film according to claim 1, wherein the organic solvent is a mixture of a poor solvent and a good solvent for the solid electrolyte.   The method for producing a solid electrolyte film according to claim 6, wherein a weight ratio of the poor solvent in the organic solvent is 10% or more and less than 100%.   The method for producing a solid electrolyte film according to claim 6 or 7, wherein the good solvent contains dimethyl sulfoxide, and the poor solvent contains an alcohol having 1 to 5 carbon atoms.   The method for producing a solid electrolyte film according to any one of claims 1 to 8, wherein the solid electrolyte is a hydrocarbon polymer.   The method for producing a solid electrolyte film according to claim 9, wherein the hydrocarbon polymer is an aromatic polymer having a sulfonic acid group. The method for producing a solid electrolyte film according to claim 10, wherein the aromatic polymer is a copolymer composed of structural units represented by general formulas (I) to (III) of Chemical Formula 1.

(However, X is H, Y is SO ₂ , Z is the structure shown in Chemical Formula (I) or (II), and n and m satisfy 0.1 ≦ n / (m + n) ≦ 0.5. .)

A casting film forming apparatus for casting a dope containing a solid electrolyte and an organic solvent from a casting die onto a support to form a casting film;
A stripping device for stripping the cast film as a film from the support;
A drying device for drying the film to form a solid electrolyte film,
The drying device moves along the conveyance path of the film, grips both end portions of the film, and then moves along the conveyance path, while gripping means for extending the film in the width direction, and the film And a drying / stretching / drying device comprising a drying means for drying the solid electrolyte film.   A solid electrolyte film produced by the production method according to claim 1. A solid electrolyte film according to claim 13;
An anode electrode that is provided in close contact with one surface of the solid electrolyte film and generates protons from a hydrogen-containing substance supplied from the outside;
An electrode film comprising: a cathode electrode that is provided in close contact with the other surface of the solid electrolyte film and synthesizes water composed of the proton that has passed through the solid electrolyte film and a gas supplied from the outside. Complex. The electrode membrane composite according to claim 14,
A fuel cell comprising: a current collector provided in contact with an electrode of the electrode membrane composite; and a current collector for transferring electrons to and from the anode electrode and the cathode electrode.

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