JP2007002012A - Porous sheet-formed material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous sheet-formed material by a sulfonic acid group-containing polyarylene ether-based polymer, capable of being extended not only as the membrane of a fuel cell, but also as cell members, various filtering membranes, filters, adsorbents, humidity-controlling materials such a humidifying material, dehumidifying material, etc., and porous supporting substrates for composite materials, etc. <P>SOLUTION: This porous sheet-formed material is characterized by containing the polyarylene ether-based polymer containing a constituting component expressed by general formula (1) [wherein, Y is sulfone or ketone; X is H or a monovalent cationic species; and Ar is a divalent aromatic group which may contain a substituent] in its molecular chain. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a porous sheet-like material mainly composed of a sulfonic acid group-containing polyarylene ether polymer useful as a polymer electrolyte membrane having excellent heat resistance and mechanical properties.

  As an example of an electrochemical device using a polymer solid electrolyte as an ionic conductor instead of a liquid electrolyte, a water electrolysis tank and a fuel cell can be mentioned. The binder resin for polymer membranes and membrane / electrode assemblies used in these materials must be sufficiently stable chemically, thermally, electrochemically and mechanically as well as proton conductivity as a cation exchange membrane. For this reason, perfluorocarbon sulfonic acid membranes, mainly “Nafion (registered trademark)” manufactured by DuPont, USA, have been used as long-term usable products.

  However, when a fuel cell using a perfluorocarbon sulfonic acid membrane is to be operated under conditions exceeding 100 ° C., the moisture content of the membrane is drastically lowered and the membrane is also softened. Further, in a fuel cell using methanol as a fuel, the performance is deteriorated due to methanol permeation in the membrane, and sufficient performance cannot be exhibited. Furthermore, even in fuel cells that are currently being studied mainly using hydrogen as a fuel and operating at around 80 ° C., it is pointed out that the cost of the membrane is too high as an obstacle to the establishment of fuel cell technology. Similar problems have been pointed out when perfluorocarbon sulfonic acid resin is used as the binder.

In order to overcome such drawbacks, various polymer electrolyte membranes in which a sulfonic acid group is introduced into a non-fluorinated aromatic ring-containing polymer have been studied. As the polymer skeleton, polyarylene ether compounds such as polyarylene ether ketones and polyarylene ether sulfones can be considered as promising structures in consideration of heat resistance and chemical stability. (For example, refer to Non-Patent Document 1), sulfonated polyether ether ketone (for example, refer to Patent Document 1), and the like have been reported. In these methods, a sulfonic acid group is introduced by reacting a polymer with a sulfonating agent, but a method of directly obtaining a sulfonated polymer by polymerization using a sulfonated monomer has also been reported (for example, Patent Documents). See 2-4.) These exhibit particularly excellent thermal stability because the sulfonic acid group is introduced on an aromatic ring having a low electron density. Moreover, since it is excellent also in mechanical characteristics, various utilization is anticipated not only as a fuel cell membrane material but as a polymer electrolyte membrane. However, the forms of use found in these reports are only due to a homogeneous dense film, and the use that can be used has been limited.
JP-A-6-93114 US Patent Application Publication No. 2002/0091225 International Publication 2003-095509 Pamphlet International Publication No. 2004-033534 Pamphlet Journal of Membrane Science, Netherlands, 1993, 83, p. 211-220

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is not only a membrane for a fuel cell but also a battery member, various filtration membranes, a filter, an adsorbent, humidification, dehumidification, etc. An object of the present invention is to provide a porous sheet material made of a sulfonic acid group-containing polyarylene ether-based polymer that can be developed on a humidity control material, a porous support base material for a composite material, and the like.

  As a result of intensive studies, the present inventors have found that the above object can be achieved by the sulfonic acid group-containing polyarylene ether compound shown below. That is, the present invention is as follows.

  The porous sheet material of the present invention is characterized by containing a polyarylene ether-based polymer having a constituent represented by the general formula (1) in a molecular chain.

(Y represents a sulfone group or a ketone group, X represents H or a monovalent cationic species, and Ar represents a divalent aromatic group which may contain a substituent.)
It is preferable that the polyarylene ether-based polymer in the porous sheet-like material of the present invention further includes a constituent represented by the general formula (2).

(However, Ar ′ represents a divalent aromatic group which may contain a substituent.)
The porous sheet material of the present invention preferably has a porosity of 5 to 85%.

The porous sheet material of the present invention preferably has a nitrogen gas permeability coefficient of 1 × 10 ⁻⁸ cm ³ · cm / cm ² · sec / cmHg or more.

  The porous sheet-like material of the present invention is preferably a porous film having a thickness of 500 μm or less, or composed of an aggregate of fibrous substances.

  By creating a porous sheet-like material using a sulfonic acid group-containing polyarylene ether polymer that is useful as a polymer electrolyte with excellent heat resistance and mechanical properties, not only fuel cell membranes, but also battery members, various filtrations It becomes possible to provide a porous sheet-like material suitable for membranes, filters, adsorbents, humidity control materials such as moisture absorption and dehumidification, and porous support base materials for composite materials. Further, since the porous sheet material of the present invention is excellent in hydrophilicity, it can be suitably used as a separation membrane for water treatment. In particular, it can be suitably used in fields such as selective separation of ions in an aqueous solution, taking advantage of the feature that the substrate is made of a polymer electrolyte.

  The porous sheet material of the present invention is mainly composed of a specific polyarylene ether-based polymer having a sulfonic acid group introduced on an aromatic ring. The porous sheet material of the present invention having such a polyarylene ether-based polymer as a main component is excellent in dimensional stability. In other words, when a polyarylene ether polymer is synthesized by an aromatic nucleophilic substitution reaction, by introducing a sulfonic acid group into an electron-withdrawing monomer such as dichlorodiphenylsulfone or difluorobenzophenone, thermal stability and mechanical properties are obtained. It is possible to obtain a polyarylene ether containing a sulfonic acid group that is excellent in the production of a porous sheet material. By producing a porous sheet-like material using the polyarylene ether, it becomes a useful material that can be developed for various uses.

  That is, the present invention is a porous sheet material comprising a polyarylene ether-based polymer having a constituent represented by the following general formula (1) in a molecular chain.

  However, in the above general formula (1), Y is a sulfone group or ketone group, X is a salt with a monovalent metal salt such as sodium or potassium, or a monovalent cationic species such as ammonium salt, in addition to H. It doesn't matter. Ar represents a divalent aromatic group which may contain a substituent.

  The porous sheet material of the present invention may contain components other than those represented by the general formula (1). The component represented by the general formula (1) is preferably 5% by weight or more, particularly preferably 15% by weight or more based on the total. This is because when the constituent component represented by the general formula (1) is less than 5% by weight of the whole, the hydrophilic characteristics of the porous sheet of the present invention tend to hardly appear. In the porous sheet material of the present invention, the constituent represented by the general formula (1) is preferably less than 95% by weight, more preferably less than 90% by weight. This is because when the component represented by the general formula (1) is 95% by weight or more, the hydrophilicity is excessively increased, and a tendency that the dimensional stability under high temperature and high humidity starts to appear.

  The polyarylene ether polymer in the present invention is represented by the following general formula (2) together with the structural component represented by the above general formula (1) from the viewpoint of further improving the dimensional stability under heating and humidification. It is preferable that the component included is included.

  However, in the general formula (2), Ar ′ represents a divalent aromatic group which may contain a substituent.

  Even when the polyarylene ether-based polymer in the present invention contains the constituent represented by the general formula (2) together with the constituent represented by the general formula (1), the general formula (1) and the general formula (2) However, the total of the constituents represented by the general formula (1) and the general formula (2) is preferably 50% by weight or more, It is particularly preferably 70% by weight or more. When the total of the constituent components represented by the general formula (1) and the general formula (2) is less than 50% by weight, the feature that the dimensional stability due to the presence of the general formula (2) is particularly excellent is unlikely to appear. It is because it tends to become.

  In addition, when the component shown by General formula (2) is included with the component shown by the said General formula (1), the mixing ratio is the component shown by General formula (1): General formula (2) The component shown is preferably 1: 0.05 to 25, and more preferably 1: 0.10 to 20. This is because when the mixing ratio is less than 1: 0.05, good dimensional stability particularly under high temperature and high humidity tends to hardly appear, and when the mixing ratio exceeds 1:25, This is because the characteristics that are excellent in the property tend to hardly appear.

  In addition, when the structural component represented by the general formula (2) is a structural component represented by the following general formula (3), the degree of polymerization of the obtained polymer tends to increase, which is preferable.

  However, Ar ″ in the general formula (3) represents a divalent aromatic group which may contain a substituent.

  In addition, the polyarylene ether-based polymer contained in the porous sheet-like material of the present invention has a component that crosslinks by heat and / or light in its molecular chain, that is, as the main chain, side chain, or terminal group of the polymer. May be contained. Examples of thermally crosslinkable groups include reactive unsaturated bond-containing components such as ethylene group, ethynyl group, and ethynylene group, but are not limited to these, and a new reaction between polymer chains is caused by reaction by heat. Any material that can form a bond may be used. Examples of photocrosslinkable groups include benzophenone groups, α-diketone groups, acyloin groups, acyloin ether groups, benzyl alkyl ketal groups, acetophenone groups, polynuclear quinone groups, thioxanthone groups, acylphosphine groups, and ethylenically unsaturated groups. Can be mentioned. Among them, a combination of a group capable of generating a radical by light such as a benzophenone group and a group capable of reacting with a radical such as an aromatic group having a hydrocarbon group such as a methyl group or an ethyl group is preferable. When using ethylenically unsaturated groups, photopolymerization of benzophenones, α-diketones, acyloins, acyloin ethers, benzyl alkyl ketals, acetophenones, polynuclear quinones, thioxanthones, acylphosphines It is preferable to add an initiator.

  The polyarylene ether-based polymer in the present invention preferably has a sulfonic acid group content in the range of 0.1 to 3.5 meq / g. When the sulfonic acid group content is less than 0.1 meq / g, there is a tendency not to show the characteristics as a polymer electrolyte. Further, when the sulfonic acid group content exceeds 3.5 meq / g, the dimensional change tends to increase when the porous sheet material absorbs moisture. The sulfonic acid group content can be determined by a titration method described later after the sulfonic acid group is converted to an acid type structure by an acidic aqueous solution treatment.

  The polyarylene ether-based polymer having the components of the general formula (1) and the general formula (2) includes, for example, dihalogenated compounds represented by the following general formula (4) and general formula (5) as monomers. It can be synthesized using an aromatic nucleophilic substitution reaction.

  In the general formulas (4) and (5), Y represents a sulfone group or a ketone group, X represents a monovalent cation species, and Z represents chlorine or fluorine.

  Specific examples of the compound represented by the general formula (4) include 3,3′-dichloro-4,4′-difluorodiphenylsulfone, 3,3′-disulfo-4,4′-difluorodiphenylsulfone, 3, 3'-disulfo-4,4'-dichlorodiphenyl ketone, 3,3'-disulfo-4,4'-difluorodiphenyl ketone, and those whose sulfonic acid group is converted to a salt with a monovalent cationic species Can be mentioned. The monovalent cation species may be sodium, potassium, other metal species, various amines, and the like, but is not limited thereto.

  Examples of the compound represented by the general formula (5) include 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile, 2,4-dichlorobenzonitrile, 2,4-difluorobenzonitrile and the like. Can do.

  In the above-described aromatic nucleophilic substitution reaction, activated difluoroaromatic compounds and dichloroaromatic compounds that can be used in addition to the above general formulas (4) and (5) include 4,4′-dichlorodiphenylsulfone, 4,4 Examples include '-difluorodiphenyl sulfone, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, decafluorobiphenyl, decafluorodiphenyl ether, decafluorobenzophenone, and the like, but are not limited thereto. Other aromatic dihalogen compounds, aromatic dinitro compounds, aromatic dicyano compounds and the like that are active in group nucleophilic substitution reactions can also be used. These compounds may be used alone, but may be used as a mixture of two or more.

  Moreover, Ar in the structural component represented by the above general formula (1), Ar ′ in the structural component represented by the above general formula (2), and the structural component represented by the above general formula (3) Examples of aromatic diol component monomers that can be used as Ar ″ in the examples include 4,4′-biphenol, bis (4-hydroxyphenyl) sulfone, 1,1-bis (4-hydroxyphenyl) ethane, 2,2 -Bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) butane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, bis (4-hydroxy-3,5-dimethylphenyl) methane, bis (4-hydroxy-2,5-dimethylphenyl) Methane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene 9,9-bis (3-phenyl-4-hydroxyphenyl) fluorene, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, hydroquinone, resorcin, 1,4-dihydroxynaphthalene, 1,8-dihydroxynaphthalene 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, bis (4-hydroxyphenyl) ketone, bis (4-hydroxy Phenyl) , Bis (4-hydroxyphenyl) thioether, oligo-1,4-phenylene ether-terminated diol compounds, and the like. In addition, it may be used for polymerization of polyarylene ether compounds by aromatic nucleophilic substitution reaction. Various aromatic diols that can be used can also be used. In addition, a substituent such as a methyl group, a halogen, a cyano group, a sulfonic acid group and a salt compound thereof may be bonded to these aromatic diols. The kind of substituent is not particularly limited, and is preferably 0 to 2 per aromatic ring. These aromatic diols can be used alone, or a plurality of aromatic diols can be used in combination. Among these, 4,4'-biphenol can be mentioned as a preferred monomer.

  In the polymerization of the polyarylene ether-based polymer in the present invention, a halogenated aromatic hydroxy compound can be added as a reactive monomer component for polymerization. The halogenated aromatic hydroxy compound used in this case is not particularly limited, but 4-hydroxy-4′-chlorobenzophenone, 4-hydroxy-4′-fluorobenzophenone, 4-hydroxy-4′-chlorodiphenylsulfone. 4-hydroxy-4′-fluorodiphenylsulfone, 4-chloro-4 ′-(p-hydroxyphenyl) diphenylsulfone, 4-fluoro-4 ′-(p-hydroxyphenyl) benzophenone, etc. can be mentioned as examples. . These can be used alone or in a mixture of two or more.

  Moreover, when introduce | transducing the above-mentioned crosslinkable terminal structure, it can obtain by adding the monofunctional terminal blocker which gives a crosslinkable group containing terminal structure in the case of superposition | polymerization of the polyarylene ether type polymer in this invention. Specific examples of functional end-capping agents include 3-fluoropropene, 3-fluoro-1-propyne, 4-fluoro-1-butene, 4-fluoro-1-butyne, 3-fluorocyclohexene, 4- Fluorostyrene, 3-fluorostyrene, 2-fluorostyrene, 4-fluoroethynylbenzene, 3-fluoroethynylbenzene, α-fluoro-4-ethynyltoluene, 4-fluorostilbene 4- (phenylethynyl) fluorobenzene, 3- ( Phenylethynyl) fluorobenzene, 3-chloropropene, 3-chloro-1-propyne, 4-chloro-1-butene, 4-chloro-1-butyne, 3-chlorocyclohexene, 4-chlorostyrene, 3-chlorostyrene, 2-chlorostyrene, 4-chloroethynylbenzene, 3-chloroethynylbenzene Zen, α-chloro-4-ethynyltoluene, 4-chlorostilbene, 4- (phenylethynyl) chlorobenzene, 3- (phenylethynyl) chlorobenzene, 3-hydroxypropene, 3-hydroxy-1-propyne, 4-hydroxy-1 -Butene, 4-hydroxy-1-butyne, 4-hydroxystyrene, 3-hydroxystyrene, 2-hydroxystyrene, 4-hydroxyethynylbenzene, 3-ethynylphenol, 4-ethynylbenzyl alcohol, 4-hydroxystilbene, 4- (Phenylethynyl) phenol, 3- (phenylethynyl) phenol, 4-chlorobenzophenone, 4-fluorobenzophenone, 4-hydroxybenzophenone, 4-methylphenol, 3-methylphenol, 2-methylphenol, 4-ethylphenol Le phenol, 3-ethylphenol, 4-propyl phenol, 4-butylphenol, 4-pentylphenol, 4-benzyl phenol. These crosslinking group-containing end-capping agents may be used alone or in combination of two or more.

  Specific examples of the monomer having a crosslinkable group include 1-butene-3,4-diol, 3,5-dihydroxystyrene, 3,5-dihydroxystilbene, 1-butyne-3,4-diol, -Butene-3,4-diol, 2,4-hexadiyne-1,6-diol, 2-ethynylhydroxyquinone, 2- (phenylethynyl) hydroquinone, 5-ethynylresorcin, 2-butene-1,4-diol, 4,4′-dihydroxystilbene, 1,4-butynediol, 1,2-bis (4-hydroxyphenyl) acetylene, 1,2-bis (3-hydroxyphenyl) acetylene, 3,3-difluoropropene, 3, 3-difluoropropyne, 3,3,3-trifluoropropyne, 3,4-difluoro-1-butene, 1,4-difluoro 2-butene, 3,4-difluoro-1-butyne, 1,4-difluoro-2-butyne, 1,6-difluoro-2,4-hexadiyne, 3,4-difluorostyrene, 2,6-difluorostyrene, 2,5-difluoroethynylbenzene, 3,5-difluoroethynylbenzene, α, α-difluoro-4-ethynyltoluene, α, α, α-trifluoro-4-ethynyltoluene, 2,4-difluorostilbene, 4, 4'-difluorostilbene, 1,2-bis (4-fluorophenyl) acetylene, 3,4-difluoro (phenylethynyl) benzene, 3,3-dichloropropene, 3,3-dichloropropyne, 3,3,3 -Trichloropropyne, 3,4-dichloro-1-butene, 1,4-dichloro-2-butene, 3,4-dichloro-1-butyne, , 4-dichloro-2-butyne, 3,4-dichlorostyrene, 2,6-dichlorostyrene, 2,4-difluorocinamic acid, 2,5-dichloroethynylbenzene, 3,5-dichloroethynylbenzene, α, α-dichloro-4-ethynyltoluene, α, α, α-trichloro-4-ethynyltoluene, 2,4-dichlorostilbene, 4,4′-dichlorostilbene, 1,2-bis (4-chlorophenyl) acetylene, 3 , 4-dichloro (phenylethynyl) benzene, 4,4′-dihydroxybenzophenone, 4,4′-dichlorobenzophenone, 4,4′-difluorobenzophenone, 4-chlorobenzophenone, 4-fluorobenzophenone, 4-hydroxybenzophenone, 1 , 1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4 -Hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) butane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxy) -3,5-dimethylphenyl) propane, bis (4-hydroxy-3,5-dimethylphenyl) methane, bis (4-hydroxy-2,5-dimethylphenyl) methane, bis (4-hydroxyphenyl) phenylmethane, Examples include 4-benzylresorcin, 2,5-dimethylresorcin, 4-ethylresorcin and the like. By adding these crosslinking group monomers during the polymerization of the polyarylene ether polymer in the present invention, a crosslinking group can be introduced into the molecular chain.

  When the polyarylene ether polymer in the present invention is polymerized by an aromatic nucleophilic substitution reaction, the activated difluoroaromatic compound and / or dichloroaromatic as exemplified by the above general formula (4) and general formula (5). A polymer can be obtained by reacting a compound with an aromatic diol in the presence of a basic compound. The polymerization can be carried out in the temperature range of 0 to 350 ° C., but is preferably 50 to 250 ° C. This is because when the temperature is lower than 0 ° C., the reaction does not proceed sufficiently, and when the temperature is higher than 350 ° C., the polymer tends to be decomposed.

  The reaction can be carried out in the absence of a solvent, but is preferably carried out in a solvent. Examples of the solvent that can be used include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, diphenyl sulfone, sulfolane, and the like. And any solvent that can be used as a stable solvent in the aromatic nucleophilic substitution reaction. These organic solvents may be used alone or as a mixture of two or more.

  Examples of the basic compound include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and the like, and in particular, those that can convert an aromatic diol into an active phenoxide structure. It is not limited and can be used.

  In the aromatic nucleophilic substitution reaction, water may be generated as a by-product. In this case, regardless of the polymerization solvent, water can be removed from the system as an azeotrope by coexisting toluene or the like in the reaction system. As a method for removing water out of the system, a water absorbing material such as molecular sieve can also be used.

  When the aromatic nucleophilic substitution reaction is carried out in a solvent, it is preferable to charge the monomer so that the resulting polymer concentration is 5 to 50% by mass. When the amount is less than 5% by mass, the degree of polymerization tends to be difficult to increase. On the other hand, when the amount is more than 50% by mass, the viscosity of the reaction system becomes too high, and the post-treatment of the reaction product tends to be difficult.

  For the polymerization, it is preferable to add monomers at the beginning of the reaction to form a polymer having a highly random chain distribution. Also, after synthesizing a block oligomer component by shifting the equivalence ratio of dihalogenated monomer and diol monomer, the chain distribution obtained by adding two or more monomers by changing the monomer combination is made into a block-like polymer. It is also possible. After completion of the polymerization reaction, the solvent is removed from the reaction solution by evaporation, and the residue is washed as necessary to obtain the desired polymer. In addition, the polymer can be obtained by precipitating the polymer as a solid by adding the reaction solution in a solvent having low polymer solubility, and collecting the precipitate by filtration. If necessary, a filtration treatment may be performed before the precipitation.

  In addition, the polyarylene ether polymer in the present invention preferably has a polymer log viscosity measured by a method described later of 0.1 or more. When the logarithmic viscosity is less than 0.1, the film is likely to be brittle when molded as a porous sheet material. Moreover, in order to improve mechanical durability as a porous sheet-like material, the reduced specific viscosity is more preferably 0.3 or more. On the other hand, if the reduced specific viscosity exceeds 5, problems in processability such as difficulty in dissolving the polymer occur, which is not preferable. As the solvent for measuring the logarithmic viscosity, polar organic solvents such as N-methyl-2-pyrrolidone and N, N-dimethylacetamide can be generally used. Can also be measured.

  The polyarylene ether-based polymer in the present invention can be used as a simple substance, but can also be used as a resin composition in combination with other polymers. Examples of these polymers include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamides such as nylon 6, nylon 6,6, nylon 6,10, and nylon 12, polymethyl methacrylate, and polymethacrylate. , Polyacrylic acid resins, polymethacrylic acid resins, polyethylene, polypropylene, various polyolefins including polystyrene and diene polymers, polyurethane resins, cellulose resins such as cellulose acetate and ethyl cellulose, polyarylate, aramid, polycarbonate, polyphenylene Sulfide, polyphenylene oxide, polysulfone, polyethersulfone, polyetheretherketone, polyetherimide, polyimide, Riamidoimido, polybenzimidazole, polybenzoxazole, aromatic polymers such as poly benzthiazole, epoxy resins, phenolic resins, novolak resins, such as thermosetting resin such as benzoxazine resin is not particularly limited. A resin composition with a basic polymer such as polybenzimidazole or polyvinylpyridine can be said to be a preferred combination for improving polymer dimensionality. If an acidic group such as a sulfonic acid group or a phosphonic acid group is further introduced into these basic polymers, the processability of the composition becomes more preferable.

  When used as these resin compositions, the polyarylene ether-based polymer in the present invention is preferably 50% by mass or more and less than 100% by mass of the entire resin composition. When the content of the polyarylene ether-based polymer in the present invention is less than 50% by mass of the entire resin composition, the porous sheet containing this resin composition has a low sulfonic acid group concentration and has characteristics as a polymer electrolyte. It tends to be unobtainable.

  The polyarylene ether-based polymer and the resin composition thereof according to the present invention include, for example, an antioxidant, a heat stabilizer, a lubricant, a tackifier, a plasticizer, a crosslinking agent, a viscosity modifier, and an antistatic agent. Various additives such as an antibacterial agent, an antifoaming agent, a dispersant, and a polymerization inhibitor may be included.

  The porosity of the porous sheet-like material of the present invention is not particularly limited, and is appropriately selected depending on the purpose of use and application. For example, when used as a diaphragm such as a battery separator, the porosity measured by a method as described later is preferably between 5 and 85%, more preferably between 10 and 80%, and more preferably between 15 and 75%. Further preferred. By setting the porosity within the range of 5 to 85%, the functional portion can be impregnated with the functional material to improve the functionality of the porous sheet material of the present invention. In addition, when the porous sheet-like material of the present invention is used as a separation membrane or a separation membrane using the voids, the permeability of ions or polarized molecules in the separated or separated liquid, etc. The mass transfer can be controlled, and the usefulness of the porous sheet-like material can be improved. In addition, when the porosity is less than 5%, there is a tendency that the aeration amount, the flow rate and the amount of the impregnating solution tend to decrease, and when the porosity exceeds 85%, the strength of the porous sheet material is low. It tends to decrease. The porosity of the porous sheet material can be adjusted, for example, by changing the retention time, processing temperature, and solvent composition when a polymer solution thin film, which will be described later, is brought into contact with the coagulation liquid.

  The void portion that imparts the porosity described above may be a through hole that extends from the front surface to the back surface of the porous sheet-like material, or may be a non-through hole that exists inside. Moreover, these may be mixed. It is appropriately selected depending on the function to be imparted to the porous sheet material and the intended use.

  The porous sheet material of the present invention can also be used as a gas separator. In this case, the air permeability is preferably 0.5 to 100 ml Air, and more preferably 1.0 to 80 ml Air. When the air permeability is less than 0.5 ml Air, there is a tendency that sufficient air permeability is not exhibited when used as a gas diaphragm, and when the air permeability exceeds 100 ml Air, it is difficult to maintain the structure of the void. This is because the reduction tends to occur. The air permeability of the porous sheet material refers to a value measured according to the air permeability measurement method of JIS L1096-1900, for example. The air permeability of the porous sheet material can be controlled, for example, by changing the porosity or changing the distribution of the void sizes.

As an index of the void state of the porous sheet material of the present invention, the permeability coefficient of nitrogen gas is preferably 1 × 10 ⁻⁸ cm ³ · cm ² · sec · cmHg or more. More preferably 2 × 10 ⁻⁸ cm ³ · cm ² · sec · cmHg or more, and further preferably 3 × 10 ⁻⁸ cm ³ · cm ² · sec · cmHg or more. This is because if the permeability coefficient of nitrogen gas is less than 1 × 10 ⁻⁸ cm ³ · cm / cm ² · sec · cmHg, the characteristics are not sufficiently exhibited. The nitrogen gas permeability coefficient refers to a value measured by the flow rate of nitrogen gas passing from the opposite side of the sheet material when, for example, a constant nitrogen gas pressure is applied from one of the sheet materials. The nitrogen gas permeability coefficient of the porous sheet material can be controlled, for example, by changing the porosity or changing the polymer structure of the present invention.

  The structure of the porous sheet material of the present invention and the method for forming the same are not particularly limited, but examples include appropriate methods known in the art for making a sheet material porous or forming an aggregate of fibrous substances. Can do.

  When making the sheet porous, for example, the polymer solution mainly composed of the polyarylene ether-based polymer in the present invention is brought into contact with a so-called non-solvent that does not dissolve the polymer but is mixed with the solvent of the polymer solution. In the process of solidification, it can be made porous. In the case of obtaining a porous sheet material as an aggregate of fibrous substances, for example, when a solution containing the polyarylene ether-based polymer as a main component in the present invention is blown from a nozzle, the solvent is evaporated by hot air, A material obtained as a material can be formed into a non-woven fabric, or cast into a fibrous base, and then dried or contacted with a poor solvent to remove the solvent to form a porous fiber aggregate. Moreover, it can also be made into the porous sheet form from what was refined | miniaturized by the electrospinning method. Further, a cut fiber made of a fiber mainly composed of the polyarylene ether-based polymer in the present invention may be made into a porous fiber aggregate. In this case, if the amount is small, a binder component may be blended to improve the bonding strength between the fibers.

  The method for making the above sheet porous is not limited. For example, the sulfonic acid group-containing polyarylene ether compound of the present invention is dissolved in an appropriate solvent, formed into a thin film by a casting method, and then an aqueous coagulating liquid. The method of coagulating with, and then drying. In this production method, the solvent for dissolving the polyarylene ether-based polymer in the present invention is not particularly limited, but N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, N-methyl-2- An appropriate one can be selected from aprotic polar solvents such as pyrrolidone and hexamethylphosphonamide, and alcohols such as methanol and ethanol. A plurality of these solvents may be used as a mixture within a possible range. The compound concentration in the solution is preferably in the range of 0.1 to 50% by mass. If the compound concentration in the solution is less than 0.1% by mass, it tends to be difficult to obtain a good molded product, and if it exceeds 50% by mass, the workability tends to deteriorate.

  The thin film obtained by casting the polymer solution is coagulated by bringing it into contact with an aqueous coagulation liquid. The composition of the coagulation liquid is not particularly limited, and water can be used alone, but a mixture of water and a lower alcohol such as methanol, ethanol, or propanol can also be used. A compounding agent such as a coagulation retardant such as polyalkylene glycol can also be added.

  The porous sheet-like material is formed by the present method by increasing the volume of the thin film-like casting due to penetration of the coagulating liquid into the polymer solution, increasing the concentration of the coagulating liquid in the thin-film casting, and the polymer solution. This occurs due to polymer coagulation following a decrease in solubility with decreasing solvent concentration. For this reason, the diffusion behavior of the solvent during the coagulation process has an important influence on the formation of the porous structure. Therefore, in addition to the selection of each solvent, control of the polymer concentration, coagulation temperature, etc. is an important factor in process control. . The sulfonic acid group in the porous sheet-like material thus obtained may contain a salt form with a cationic species, but if necessary, it can be converted into free sulfonic acid groups by acid treatment. It can also be converted.

  Although the thickness of the porous sheet-like material of the present invention can be appropriately selected according to the purpose, it is generally preferably 500 μm or less from the viewpoint of productivity. On the other hand, when the thickness is less than 5 μm, the handleability is lowered, so that it is preferably 5 μm or more, more preferably 10 μm or more.

  The porous sheet material of the present invention can be used alone, but can be used in combination with other material sheets and films. It can also be used in combination with other materials. For example, when used as a proton conductive material, other proton conductive materials or non-conductive materials are contained in the voids of the porous sheet-like material, and conductivity, hydrophilicity-hydrophobicity, shape stability, It can be said that it is also preferable to adjust the heat resistance, chemical stability, long-term durability and the like as appropriate.

The polyarylene ether-based polymer and the resin composition thereof used in the porous sheet-like material of the present invention introduce a structure that is crosslinked by heat and / or light and the like, and are crosslinked by heat treatment and / or light irradiation treatment. Furthermore, it can be excellent in dimensional stability. The heating temperature at the time of thermal crosslinking varies depending on the structure of the crosslinkable polyarylene ether, the type of crosslinking group, the amount of crosslinking group introduced, and the like, but is usually 150 to 450 ° C, preferably 200 to 400 ° C. The heating time varies depending on the heating temperature and the structure of the crosslinkable polyarylene ether, but is usually 0.01 to 50 hours, preferably 0.02 to 24 hours. The pressure may be normal pressure, reduced pressure, or increased pressure. When the heating temperature is high, the sulfonic acid group is preferably heat-treated in a salt state. The light source used for photocrosslinking is not particularly limited, and a low-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, and the like can be used. The irradiation dose may vary depending on the polymer structure and its thickness, usually, 100~50000mJ / cm ^2, preferably 300~30000mJ / cm ^2. It may be a crosslinking reaction by irradiation with radiation such as γ rays or electron beams.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these Examples. Various measurements were performed as follows.

1. Solution viscosity The polymer powder was dissolved in N-methyl-2-pyrrolidone at a concentration of 0.5 g / dl, the viscosity was measured using a Ubbelohde viscometer in a constant temperature bath at 30 ° C., and the logarithmic viscosity (ln [ta / tb] / c) (ta is the drop time of the sample solution, tb is the drop time of the solvent only, and c is the polymer concentration).

2. Heat resistance evaluation (TGA)
Using a thermogravimetry meter (TGA-50, manufactured by Shimadzu Corporation), measurement was performed in an argon atmosphere at a heating rate of 10 ° C./min (while being held at 150 ° C. for 30 minutes to sufficiently remove moisture). .

3. Ion Exchange Capacity The sample dried overnight under a nitrogen atmosphere was weighed, stirred with an aqueous sodium hydroxide solution, and then ion exchange capacity (IEC) was determined by back titration with an aqueous hydrochloric acid solution.

4). Porosity Porous sheet-like material is cut into a circle having a diameter of 60 mm, and its volume and weight are obtained. From the obtained results, porosity (volume%) = 100 × {volume (cm ³ ) −weight (g) / resin The average density (g / cm ³ )} / volume (cm ³ ) was calculated.

5. Permeability coefficient of nitrogen gas Cut out a porous sheet material into a circular shape with a diameter of 4.7 cm, set it in a self-made gas permeation device, apply a nitrogen pressure of 0.1 MPa from one side of the membrane, and pass it to the opposite side of the membrane The amount of nitrogen was measured with a soap film flow meter.

<Example 1>
3,3′-disulfo-4,4′-dichlorodiphenylsulfone disodium salt (abbreviation: S-DCDPS) 3.330 g (0.00678 mole), 2,6-dichlorobenzonitrile (abbreviation: DCBN) 2.9983 g ( 0.01743 mole), 4.580 g (0.02421 mole) of 4,4′-biphenol, and 3.8484 g (0.02784 mole) of potassium carbonate were weighed into a 100 ml four-necked flask and flushed with nitrogen. After 35 ml of NMP was added and stirred at 150 ° C. for 1 hour, the reaction was continued by raising the reaction temperature to 195-200 ° C. and sufficiently increasing the viscosity of the system (about 7 hours). After standing to cool, the reaction solution was poured into water to precipitate into a strand. The obtained polymer was washed in boiling water for 1 hour and then dried. The logarithmic viscosity of the polymer was 1.31.

1 g of polymer is dissolved in 5 ml of NMP, applied onto a polyester film having a thickness of 100 μm, and the resulting multilayer film is immersed in a coagulating liquid consisting of water / methanol (3/1 volume ratio) at 25 ° C. to solidify the polymer. After that, the sulfonated polyarylene ether-based polymer film was peeled off from the polyester film and dried in an inert oven at 130 ° C. to obtain a porous film (porous sheet material) having a thickness of about 20 μm. When the TGA measurement of this film was performed, the weight reduction start temperature was 411 ° C. The porosity was 55%. The nitrogen permeability coefficient was 2 × 10 ⁻⁵ cm ³ · cm / cm ² · sec · cmHg.

<Example 2>
The porous film obtained in Example 1 was immersed in dilute sulfuric acid (concentrated sulfuric acid 6 ml, water 300 ml) for 1 day to remove the salt, and then immersed in pure water twice for 1 hour each time. Ingredients were removed and dried. The weight loss starting temperature by thermogravimetry of this film was 301 ° C. The IEC determined by titration was 1.43 meq / g. The porosity was 60%. The nitrogen permeability coefficient was 7 × 10 ⁻⁵ cm ³ · cm / cm ² · sec · cmHg.

<Example 3>
The polymer solution obtained in Example 1 was heated to 150 ° C. and blown out from a fine nozzle into a nitrogen flow atmosphere at 150 ° C. to obtain a fine fibrous material. By compressing the obtained fibrous assembly with a hot press set at 180 ° C., a porous sheet made of the fibrous material assembly was created, immersed in pure water for 1 day, and then heated at 130 ° C. The porous sheet-like material was obtained by drying in an inert oven. The porosity was 65%. The nitrogen permeability coefficient was 8 × 10 ⁻⁵ cm ³ · cm / cm ² · sec · cmHg.

<Example 4>
A nonwoven fabric was obtained by spinning the liquid obtained in Example 1 using the apparatus shown in FIG. That is, the liquid was sent to the nozzle using a metering pump. The nozzle was installed toward the drum rotating cathode. At this time, the distance between the nozzle and the cathode is 10 to 30 cm. The applied voltage is 10 to 30 kV. The voltage and nozzle-cathode distance are kept just before the corona voltage occurs. The obtained nonwoven fabric was washed with water overnight and then air-dried for one day to obtain a porous sheet material. The porosity was 40%.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The porous sheet-like material of the present invention containing a specific polyarylene ether compound as a main component includes various battery members, various filtration membranes, filters, adsorbents, humidity control materials such as humidification and dehumidification, and porous support for composite materials. It can be applied to a wide range of uses such as substrates. In addition to utilizing the properties of a proton conductive polymer electrolyte, it can be used as a porous proton exchange membrane type fuel cell membrane, and other proton conductive materials and non-conductive materials can be placed in the voids of the porous sheet. It can also be used as a composite fuel cell membrane. Further, since the porous sheet material of the present invention is excellent in hydrophilicity, it can be suitably used as a separation membrane for water treatment. In particular, it can be suitably used in fields such as selective separation of ions in an aqueous solution, taking advantage of the feature that the substrate is made of a polymer electrolyte.

It is a figure which shows typically an example of the spinning apparatus used in Example 4. FIG.

Claims (6)

A porous sheet material comprising a polyarylene ether-based polymer having a constituent represented by the general formula (1) in a molecular chain.

(Y represents a sulfone group or a ketone group, X represents H or a monovalent cationic species, and Ar represents a divalent aromatic group which may contain a substituent.) The porous sheet-like material according to claim 1, wherein the polyarylene ether-based polymer further includes a constituent represented by the general formula (2).

(However, Ar ′ represents a divalent aromatic group which may contain a substituent.)   The porous sheet material according to claim 1 or 2, wherein the porosity is between 5 and 85%. Porous sheet material according to claim 1, wherein the permeability coefficient of the nitrogen gas is ^{1 × 10 -8 cm 3 · cm} / cm 2 · sec / cmHg or more.   It is a porous film with a film thickness of 500 micrometers or less, The porous sheet-like material in any one of Claims 1-4 characterized by the above-mentioned. The porous sheet-like material according to any one of claims 1 to 4, comprising an aggregate of fibrous substances.

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