JP2002146015A - Ion-conductive polyazole containing phosphonic acid group - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer electrolyte having not only good durable stability but also excellent ionic conductivity by introducing phosphonic acid groups expected to have high heat resistance into a polymer which skeleton itself has high heat resistance. SOLUTION: This polyazole compound containing phosphonic acid groups is characterized by having a conductivity of >=0.001 [S/cm] determined by measuring an alternating current impedance of 10,000 Hz at 80 deg.C and 95%RH, having a 3 wt.% loss temperature of >=400 deg.C based on the weight of a sample reaching 200 deg.C on the measurement of TGA, having an average mol.wt. of 1,000 to 1,000,000, and when plural repeating units are contained, they are mainly randomly and/or alternately binding to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a phosphonic acid-containing polyazole compound useful as a polymer electrolyte membrane.

[0002]

2. Description of the Related Art As an example of an electrochemical device using a polymer solid electrolyte as an ion conductor instead of a liquid electrolyte, a water electrolysis tank or a fuel cell can be used. The polymer membrane used for these must be chemically, thermally, electrochemically and mechanically sufficiently stable as well as proton conductivity as a cation exchange membrane. For this reason, a perfluorocarbon sulfonic acid membrane typically represented by "Nafion (registered trademark)" manufactured by DuPont U.S.A. has been used as a material that can be used for a long time. However, if you try to operate under conditions over 100 ° C,
The water content of the film sharply drops, and the softening of the film becomes remarkable. For this reason, in a fuel cell that uses methanol as a fuel, which is expected in the future, performance is reduced due to permeation of methanol in the membrane, and sufficient performance cannot be exhibited. In addition, hydrogen, which is currently being studied, is used as fuel.
It has been pointed out that, even in a fuel cell operated at around 0 ° C., the cost of the membrane is too high as an obstacle to the establishment of fuel cell technology.

In order to overcome such disadvantages, various studies have been made on polymer electrolyte membranes in which a sulfonic acid group is introduced into a non-fluorinated polymer. For example, sulfonated polyarylether sulfone (Journal of Membrane Sc
ience, 83 , 211 (1993)), sulfonated polyetheretherketone (JP-A-6-93114), sulfonated polystyrene and the like. However, the sulfonic acid group introduced on the aromatic ring easily undergoes a desulfonate reaction due to acid or heat, and thus cannot be said to have sufficient durability for use as an electrolyte membrane for a fuel cell.

[0004] On the other hand, there are few phosphonic acid-containing aromatic polymers which may be more excellent in heat resistance than sulfonic acid groups, from the viewpoint of a polymer electrolyte. For example, in US Pat. No. 5,498,784, polybenzoxazole composed of 4,4 ′-(2,2,2-trifluoro-1- (trifluoromethyl) ethylidene) bis (2-aminophenol) has a dicarboxylic acid component. Has been reported in which 5% to 50% of 3,5-dicarboxyphenylphosphonic acid is
Although attention is paid to good solubility and possibility as a composite material, it has not been considered as a polymer electrolyte for battery use. In fact, it is clear that this polymer is characterized by its alcohol solubility and is not suitable for use with electrolyte membranes for methanol fueled fuel cells. Also,
The ionic conductivity also shows only low values. In addition, JP-A-11
In -286545, a phosphorus-containing polyamide copolymer such as 3,5-dicarboxyphenylphosphonic acid is reported, but only properties focusing on the heat resistance have been investigated. Under acidification conditions used for a fuel cell, this polymer undergoes hydrolysis and cannot be used as an electrolyte membrane.

[0005]

An object of the present invention is to replace a sulfonic acid group, which has been considered as a polymer electrolyte, by replacing a sulfonic acid group, which is expected to have higher heat resistance, with the heat resistance of the polymer skeleton itself. An object of the present invention is to obtain a polymer electrolyte which is excellent not only in durability stability but also in ionic conductivity by being introduced into a polymer having high performance.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, a polyazole containing phosphonic acid has a high heat resistance and a high ionic conductivity. An electrolyte was obtained.

That is, according to the present invention, the conductivity obtained by measuring the AC impedance of 10,000 Hz at 80 ° C. and 95% RH is 0.001 [S / cm] or more, 3% weight loss temperature based on the weight of the sample at 400 ° C. or higher and an average molecular weight of 1,000 to 1,000,000
And a phosphonic acid-containing polyazole compound characterized by being mainly and randomly and / or alternately bonded when a plurality of repeating units are present. In the present invention, the conductivity obtained by measuring the AC impedance at 10,000 Hz at 80 ° C. and 95% RH is 0.
01 [S / cm] or more and 20 in TGA measurement.
Particularly excellent performance is exhibited when the 3% weight loss temperature based on the sample weight at the time of the 0 ° C. temperature rise is 400 ° C. or more and the main chain structure mainly comprises a polyoxazole skeleton. The molded product of the present invention is obtained by treating the polymer compound in the same manner as in the method of molding a polymer compound, that is, extruding from a polymerization solution or an isolated polymer, spinning, rolling, casting, or any other method. It is formed into a film. The present invention is a molded product characterized by containing these compounds as main components, and can be processed into fibers, films, sheet-like materials, etc., and particularly effective is exhibited by forming a film. Is done.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The phosphonic acid-containing polyazole compound referred to in the present invention refers to aromatic polyoxazoles, polythiazoles, polyimidazoles containing phosphonic acid groups, and compositions and copolymers in which they are mixed. Generally, it can be represented by a repeating unit structure as shown in the following formula.

[0009]

Embedded image (In the general formula 1, R represents a tetravalent aromatic group capable of forming an azole ring, X represents O, S, or NH. R ′ represents a divalent aromatic group, an aliphatic group, or an aliphatic group. R ′ represents a cyclic group, and has a phosphonic acid group in all or a part of R′.R and R ′ each may be a single ring, a combination of a plurality of aromatic rings, or a condensed ring. And may have a stable substituent other than phosphonic acid.
R 'may have a heterocyclic structure in which N, S, O, etc. are present in the aromatic ring.

Further, it may contain a repeating unit represented by the following formula together with the general formula 1.

Embedded image (Where X represents O, S, or NH, and R "represents a trivalent aromatic group capable of forming an azole ring.)

The route for synthesizing the phosphonic acid-containing polyazole compound of the present invention represented by the above general formula 1 is not particularly limited, but usually, a azole ring represented by R in the formula can be formed.
An aromatic diamine diol forming a divalent aromatic group unit,
It can be synthesized by reacting a compound selected from aromatic diamine dithiol, aromatic tetramine and derivatives thereof with a compound selected from dicarboxylic acid forming a divalent group represented by R ′ and derivatives thereof. At that time, phosphonic acid groups can be introduced into the resulting polyazole by using a dicarboxylic acid containing phosphonic acid among the dicarboxylic acids used.

Specific examples of the aromatic diamine diol, aromatic diamine dithiol and aromatic tetramine include 2,2.
5-dihydroxyparaphenylenediamine, 4,6-dihydroxymetaphenylenediamine, 2,5-diamino-1,4-benzenedithiol, 4,6-diamino-
1,3-benzenedithiol, 2,5-diamino-3,
6-dimethyl-1,4-benzenedithiol, 1,2,2
4,6-tetraaminobenzene, 3,3′-dihydroxybenzidine, 3,3′-diamino-4,4′-diphenylbenzenediol, 3,3′-dimercaptobenzidine, 3,3′-diamino-4, 4′-diphenylbenzenedithiol, 3,3′-diaminobenzidine, bis (4-amino-3-hydroxyphenyl) ether,
Bis (3-amino-4-hydroxyphenyl) ether, bis (4-amino-3-mercaptophenyl) ether, bis (3-amino-4-mercaptophenylphenyl) ether, 3,3 ′, 4,4′- Tetraaminodiphenyl ether, bis (4-amino-3-hydroxyphenyl) sulfone, bis (3-amino-4-hydroxyphenyl) sulfone, bis (4-amino-3-mercaptophenyl) sulfone, bis (3-amino-4) -Mercaptophenylphenyl) sulfone, 3,3 ', 4,4
'-Tetraaminodiphenyl sulfone, 2,2-bis (4-amino-3-hydroxyphenyl) propane,
2,2-bis (3-amino-4-hydroxyphenyl)
Propane, 2,2-bis (4-amino-3-mercaptophenyl) propane, 2,2-bis (3-amino-4-
Mercaptophenylphenyl) propane, 2,2-bis (3,4-diaminophenyl) propane, 2,2-bis (4-amino-3-hydroxyphenyl) hexafluoropropane, 2,2-bis (3-amino- 4-hydroxyphenyl) hexafluoropropane, 2,2-bis (4-amino-3-mercaptophenyl) hexafluoropropane, 2,2-bis (3-amino-4-mercaptophenylphenyl) hexafluoropropane, 2
-Bis (3,4-diaminophenyl) hexafluoropropane, bis (4-amino-3-hydroxyphenoxy) benzene, bis (3-amino-4-hydroxyphenoxy) benzene, bis (4-amino-3-mercaptophenoxy) ) Benzene, bis (3-amino-4-mercaptophenoxy) benzene, bis (3,4, -diaminophenoxy) benzene and the like, but are not limited thereto. Further, a plurality of these compounds can be used at the same time. These aromatic diamine diol, aromatic diamine dithiol, if necessary, hydrochloric acid,
It may be a salt with an acid such as sulfuric acid or phosphoric acid, and may contain a known antioxidant such as tin (II) chloride or a phosphorous acid compound.

Specific examples of phosphonic acid-containing dicarboxylic acids include, for example, 2,5-dicarboxyphenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid, 2,5
Examples include, but are not limited to, phosphonic acid-containing dicarboxylic acids such as -bisphosphonoterephthalic acid, and derivatives thereof. The phosphonic acid-containing dicarboxylic acids can be introduced in the form of a copolymer together with the dicarboxylic acid containing no phosphonic acid, in addition to those alone. Examples of dicarboxylic acids that can be used with the phosphonic acid-containing dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, biphenyl dicarboxylic acid, terphenyl dicarboxylic acid, 2,2
General dicarboxylic acids reported as polyester raw materials such as -bis (4-carboxyphenyl) hexafluoropropane can be used, and are not limited to those exemplified here. When a phosphonic acid-free dicarboxylic acid is used together with a phosphonic acid-containing dicarboxylic acid, the phosphonic acid-containing dicarboxylic acid is preferably at least 20 mol% of all dicarboxylic acids in order to clarify the effect of the phosphonic acid. In order to bring out a remarkable effect, the content is more preferably at least 50 mol%. The purity of the dicarboxylic acid containing a phosphonic acid group is not particularly limited, but is preferably 97% or more, and 9% or more.
8% or more is more preferable. Polyazole polymerized from a dicarboxylic acid containing a phosphonic acid group as a raw material contains a phosphonic acid group because the degree of polymerization tends to be lower than when a dicarboxylic acid containing no phosphonic acid group is used. It is preferable to use a dicarboxylic acid having as high a purity as possible.

The route for introducing the polyazole unit represented by the above general formula 2 is not particularly limited, but usually, an amino group is added at the ortho position to form a trivalent aromatic group unit capable of forming an azole ring represented by R in the formula. Compounds selected from aromatic carboxylic acids having two, aromatic carboxylic acids having an amino group and a hydroxyl group in an ortho position, aromatic carboxylic acids having an amino group and a mercapto group in an ortho position, and derivatives thereof. It can be obtained by polymerization.

The method for synthesizing these phosphonic acid-containing polyazole compounds is not particularly limited.
e, Encyclopedia of Polymer Science and Engineerin
g, 2nd Ed., Vol. 11, P. 601 (1988), and can be synthesized by dehydration and cyclization polymerization using polyphosphoric acid as a solvent. Further, polymerization by a similar mechanism using a methanesulfonic acid / phosphorus pentoxide mixed solvent system instead of polyphosphoric acid can also be applied. Alternatively, use a method in which a precursor polymer such as a polyamide structure is prepared in a suitable organic solvent or in a reaction of a mixed monomer melt, and then converted to a target polyazole structure by a cyclization reaction by appropriate heat treatment or the like. Can be. In order to synthesize a polymer having high thermal stability, polymerization using polyphosphoric acid, which is generally used, is preferred. However, in polymerizations that can be carried out for a long time as conventionally reported, in a system containing a phosphonic acid-containing monomer, the thermal stability of the obtained polymer may be reduced. For this reason, in the present invention, the polymerization time cannot be specified unconditionally because there is an optimum time depending on the combination of individual monomers, but it is preferable to effectively shorten the polymerization time. As a result, a polymer having a large amount of phosphonic acid groups can be obtained with high thermal stability. The molecular weight of these phosphonic acid group-containing polyazoles is not particularly limited.
Preferably, it is 0,000,000. If it is too low, it is difficult to obtain a good molded product. In addition, when there are a plurality of repeating units, they are mainly randomly and / or alternately bonded, and thus have a characteristic of exhibiting stable performance as a polymer electrolyte membrane.

The phosphonic acid group-containing polyazole of the present invention can be extruded from a polymerization solution or an isolated polymer and formed into a fiber or film by any method such as spinning, rolling, and casting. Among them, molding from a solution dissolved in an appropriate solvent is preferable. Solvents that dissolve include N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, N-methyl-2.
Suitable ones can be selected from aprotic polar solvents such as pyrrolidone and hexamethylphosphonamide and strong acids such as polyphosphoric acid, methanesulfonic acid, sulfuric acid and trifluoroacetic acid, but are not limited thereto. These solvents may be used as a mixture of two or more as much as possible. As a means for improving solubility, a solvent obtained by adding a Lewis acid such as lithium bromide, lithium chloride or aluminum chloride to an organic solvent may be used. The concentration of the polymer in the solution is preferably in the range of 0.1 to 30% by weight. If it is too low, moldability deteriorates, and if it is too high, processability deteriorates.

A known method can be used to obtain a molded body from the solution. For example, by heating, drying under reduced pressure, or immersing in a polymer non-solvent that is miscible with a solvent that dissolves the polymer, the solvent can be removed to obtain a molded product of a phosphonic acid group-containing polyazole compound. When the solvent is an organic solvent, the solvent is preferably distilled off by heating or drying under reduced pressure. When the solvent is a strong acid, it is preferable to immerse in water, methanol, acetone or the like. At this time, if necessary, it can be formed into a fiber or a film in a form of a composite with another polymer. When combined with a polybenzazole-based polymer having a similar solubility behavior, it is convenient for good molding.

A preferred method of forming a film containing the phosphonic acid group-containing polyazole compound of the present invention as a main component is casting from a solution. The solvent is removed from the cast solution as described above to obtain a phosphonic acid group-containing polyazole film. Drying of the solvent is preferred from the viewpoint of film uniformity. Further, in order to avoid decomposition and deterioration of the polymer and the solvent, it is preferable to dry under reduced pressure at a temperature as low as possible. As a substrate to be cast, a glass plate, a Teflon (registered trademark) plate, or the like can be used. When the viscosity of the solution is high, if the substrate or the solution is heated and cast at a high temperature, the viscosity of the solution is reduced and the solution can be easily cast. The thickness of the solution at the time of casting is not particularly limited, but is preferably from 10 to 1,000 μm. If the thickness is too small, the film form cannot be maintained, and if the thickness is too large, a non-uniform film tends to be formed. More preferably, it is 100 to 500 μm. A known method can be used for controlling the cast thickness of the solution. For example, the thickness can be controlled to a constant thickness using an applicator, a doctor blade, or the like, or the thickness and the amount of the solution can be controlled with a constant casting area using a glass petri dish. A more uniform film can be obtained from the cast solution by adjusting the removal rate of the solvent. For example, when heating, it is possible to lower the evaporation rate at the initial stage by lowering the temperature. When immersed in a non-solvent such as water, the coagulation rate of the polymer can be adjusted by leaving the solution in air or an inert gas for an appropriate time. The membrane of the present invention can have any thickness depending on the purpose, but is preferably as thin as possible from the viewpoint of ion conductivity. Specifically, it is preferably 200 μm or less, more preferably 50 μm or less, and most preferably 20 μm or less.

The phosphonic acid group-containing polyazole polymer of the present invention is suitable for use as an ion exchange membrane for a fuel cell or the like in the form of a film or a film. Furthermore, by using the polymer structure of the present invention as a main component, it can also be used as a binder resin for producing a joined body of the ion exchange membrane and the electrode of the present invention. The phosphonic acid-containing polyoxazole polymer of the present invention can be used at 10,000 ° C. and 95% RH at 10,000 ° C.
It is characterized in that the conductivity obtained by measuring the AC impedance at 0 Hz is 0.001 [S / cm] or more and the 3% weight loss temperature in TGA measurement is 400 ° C. or more. Conductivity is 0.01 [S
/ Cm] or more, the 3% weight loss temperature in TGA measurement is 400 ° C. or more, and the case where the main chain structure mainly comprises a polyoxazole skeleton is particularly preferable. Supposedly, it is included in the polyazole structure containing a phosphonic acid group as described above. Even if the 3% weight loss temperature in TGA measurement is 400 ° C. or more, 80 ° C. and 95%
If the measured conductivity at 10,000 Hz in RH shows a conductivity of less than 0.001 [S / cm], the water retention at high temperatures may be inferior to the polymer of the present invention, The object of the present invention cannot be achieved. Further, it is supposed that it is included in the polyazole structure containing a phosphonic acid group as described above, and it is used at 10,000 ° C. and 95% RH.
Even if the conductivity measured by measuring the AC impedance at 00 Hz is 0.001 [S / cm] or more, the TGA
If the measured 3% weight loss temperature is less than 400 ° C., the durability at high temperatures may be inferior to the polymer of the present invention, and the object of the present invention cannot be achieved.

The phosphonic acid-containing polyazole polymer of the present invention has a 3% weight loss temperature of 400 ° C. or more based on the sample weight at the time of 200 ° C. temperature rise in TGA measurement, which will be described in detail later. Although it is characterized by the above, preferably, the 3% weight loss temperature measured under the same conditions is 420 ° C. or more. More preferably, the 3% weight loss temperature measured under the same conditions is 450 ° C. or higher. what if,
Even if it is contained in the polyazole structure containing a phosphonic acid group as described above, 3% based on the sample weight at the time of 200 ° C. temperature rise in TGA measurement.
When the weight loss temperature is less than 400 ° C., the object of the present invention cannot be achieved because the durability stability at high temperature is inferior to that of the polymer of the present invention.

Further, the film according to the present invention has excellent solvent resistance and mechanical properties. For example, with respect to solvent resistance, there is little swelling in an acidic aqueous solution, and with regard to mechanical properties, there is no fear of breakage or the like in handling the film even when the film thickness is small.

[0022]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. In addition, various measurements were performed as follows. TGA measurement: TGA measurement was performed on about 5 mg of a sample under an argon atmosphere using TGA-50 manufactured by Shimadzu Corporation. The temperature was raised at 10 ° C / min to 100 ° C for 30 minutes 10 minutes.
After the sample was kept at 0 ° C. to remove moisture from the sample, the measurement was performed at 10 ° C./min up to 600 ° C. The temperature at which 3% of the weight of the sample was reduced based on the weight of the sample at the time of 200 ° C temperature rise was defined as a 3% weight loss temperature. Ion conductivity measurement: Probe for self-made measurement (made by Teflon)
Platinum wire (diameter: 0.2 mm) on the surface of the strip-shaped film sample
And hold the sample in a constant temperature / humidity oven at 80 ° C and 95% RH (Nagano Kagaku Kikai Seisakusho Co., Ltd., LH-20-01), and measure the AC impedance between platinum wires at 10 KHz at 1250 FREQ by SOLARTROON.
Measured by UENCY RESPONSE ANALYSER. The measurement was performed while changing the distance between the electrodes, and the conductivity in which the contact resistance between the film and the platinum wire was canceled was calculated by the following equation from the gradient plotting the distance between the electrodes and the measured resistance value. Conductivity [S / cm] = 1 / Film width [cm] x Film thickness [cm] x Resistance gradient [Ω / cm] Polymer logarithmic viscosity: Using an Ostwald viscometer using sulfuric acid or methanesulfonic acid as a solvent Measured.
When sulfuric acid was used, the measurement was performed at 30 ° C. on a 0.5 g / dl sulfuric acid solution. When methanesulfonic acid was used, the measurement was performed at 25 ° C. on a 0.05 g / dl methanesulfonic acid solution. IR measurement: Biorad FTS-
40. It was measured by a microscopic transmission method using Biorad UMA-300A for a microscope.

Example 1 1.830 g (6.575 × 10 ⁻³ mole) of 3,3 ′, 4,4′-tetraaminodiphenylsulfone (abbreviation: TAS), 3,5-dicarboxyphenylphosphonic acid (abbreviation: DCP, purity) 9
1.618 g (6.575 × 10 −3 mole) of 9%), 20.48 g of polyphosphoric acid (phosphorus pentoxide content 75%) and 16.41 g of phosphorus pentoxide are weighed into a polymerization vessel. Pour nitrogen and raise the temperature to 100 ° C while stirring slowly on an oil bath. After maintaining at 100 ° C. for 1 hour, the temperature was raised to 155 ° C. for 1 hour, and then to 210 ° C. for 5 hours. After completion of the polymerization, the mixture was left to cool, water was added to take out the polymer, and washing with water was repeated using a household mixer until the pH test paper became neutral. The obtained polymer is 80 ° C
And dried under reduced pressure overnight. The logarithmic viscosity of the polymer with the obtained sulfuric acid solution was 1.20. 300 mg of the polymer and 2.5 ml of methanesulfonic acid were stirred at room temperature to obtain a homogeneous solution. The film was cast on a hot plate to a thickness of about 180 mm on a glass plate, allowed to stand at room temperature for 1 hour, and then immersed in water. Change the water occasionally and continue immersion for several days. The film was taken out, air-dried while fixing the surroundings and suppressing shrinkage. Finally, the film was dried overnight at 80 ° C. using a vacuum drier to prepare a film for measuring ion conductivity. TGA measurement of the obtained film showed that the 3% weight loss temperature was 490 ° C. The ionic conductivity at 80 ° C. and 95% RH is 0.03.
It showed 0 S / cm, and the measured ionic conductivity kept stable performance for a long time.

Example 2 In Example 1, 70:30 was used as the dicarboxylic acid component.
(Molar ratio) of DCP and terephthalic acid (abbreviation: T
PA), and polymerization and various measurements were carried out in the same manner as in Example 1 except that the components were charged so that the total amount became (6.575 × 10 −3 mole). 0.92, 3% logarithmic viscosity of polymer
Weight loss temperature is 452 ° C, ionic conductivity is 0.011S
/ Cm, and the measured ionic conductivity maintained stable performance over a long period of time. The IR spectrum of the polymer is shown in FIG.

Comparative Example 1 3,3'-Dihydroxybenzidine (abbreviation: HAB) 1.86
0g (8.602 × 10 ^-3 mole), 2.307 g (8.602) of monosodium 2,5-dicarboxybenzenesulfonate (abbreviation: STA)
x10-3 mole), polyphosphoric acid (phosphorus pentoxide content 75%) 24.9
8 g and 20.02 g of phosphorus pentoxide are weighed into a polymerization vessel. Pour nitrogen and raise the temperature to 100 ° C while stirring slowly on an oil bath. After maintaining at 100 ° C. for 1 hour, the temperature was raised to 155 ° C. for 1 hour, and the temperature was raised to 210 ° C. for 4 hours.
After completion of the polymerization, the mixture was left to cool, water was added to take out the polymer, and washing with water was repeated using a household mixer until the pH test paper became neutral. The obtained polymer was dried under reduced pressure at 80 ° C. overnight. The logarithmic viscosity of the obtained polymer with a sulfuric acid solution is
0.87. To 0.12 g of the synthesized polymer sample, 1.8 g of methanesulfonic acid was added, and the mixture was stirred with a magnetic stirrer for several hours to dissolve, and poly {(benzo [1,2-
d: 5,4-d '] bisoxazole-2,6-diyl) -1,4-phenylene {1 wt% methanesulfonic acid dope (intrinsic viscosity = 24 dl / g) (3 g) was added, and the mixture was further stirred for several hours. A homogeneous solution was obtained. The film was cast on a hot plate to a thickness of about 180 mm on a glass plate, allowed to stand at room temperature for 1 hour, and then immersed in water. Change the water occasionally and continue immersion for several days. The film was taken out, air-dried while fixing the surroundings and suppressing shrinkage. Finally, the film was dried overnight at 80 ° C. using a vacuum drier to prepare a film for measuring ion conductivity. The ionic conductivity at 80 ° C. and 95% RH is 0.11.
2 S / cm, and the measured ionic conductivity gradually decreased. TGA measurement of the obtained film showed that the 3% weight loss temperature was 393 ° C.

Example 3 A 200 ml glass separable flask was charged with 4,6-diaminoresorcinol dihydrochloride (abbreviation: DAR) 9.0.
63 g (4.254 × 10 ^-2 mol), DCP (purity 9
9.469 g (4.254 × 10 ^-2 mol),
43.86 g of polyphosphoric acid (phosphorus pentoxide content: 84%) and 14.49 g of phosphorus pentoxide were weighed, and 0.5 hours at 70 ° C, 5 hours at 120 ° C, 19 hours at 140 ° C under a nitrogen stream.
The mixture was heated in an oil bath with stirring at 165 ° C. for 19 hours and at 190 ° C. for 5 hours to obtain a yellow translucent hard rubber-like dope. The dope was charged into ion-exchanged water and washed repeatedly with water until the pH test paper became neutral. The obtained polymer was dried under reduced pressure at 80 ° C. overnight. The logarithmic viscosity of the obtained polymer in a methanesulfonic acid solution is 1.
43 dl / g. FIG. 2 shows the IR spectrum of the polymer. 0.08 g of the polymer was methanesulfonic acid.2.
Dissolved in 0 ml at room temperature. There, poly {(benzo [1,2-d: 5,4-d '] bisoxazole-2,
2.00 g of a 1 wt% polyphosphoric acid solution (6-diyl) -1,4-phenylene} (phosphorus pentoxide content: 84%) was added and further stirred at room temperature to obtain a homogeneous solution. The solution was cast on a glass plate to a thickness of about 180 μm, allowed to stand for 10 minutes, and then immersed in water. The water was changed from time to time and the water immersion continued for several days. The film was taken out, air-dried while fixing the surroundings and suppressing shrinkage. Finally, the film was dried overnight at 80 ° C. using a vacuum drier to prepare a film for measuring ion conductivity. TGA measurement of the obtained film showed that the 3% weight loss temperature was 443 ° C. The ionic conductivity at 80 ° C. and 95% RH was 0.053 S / cm, and the measured ionic conductivity maintained stable performance for a long time.

Comparative Example 2 In a 200 ml glass separable flask, 4,6-diaminoresorcinol dihydrochloride (abbreviation: DAR) 2.4 was added.
12 g (1.132 × 10 ^-2 mol), monosodium 3,5-dicarboxybenzenesulfonate (abbreviation: SI
A) 3.036 g (1.132 × 10 ^-2 mol), 43.86 g of polyphosphoric acid (phosphorus pentoxide content: 84%) and 14.97 g of phosphorus pentoxide were weighed, and were weighed at 70 ° C. under a nitrogen stream at 30 ° C.
Min, 120 ° C for 3 hours, 140 ° C for 18 hours, 190 ° C
Then, the mixture was heated in an oil bath while stirring in the order of 9 hours to obtain a yellow translucent slightly spinnable, slightly rubbery dope. The dope was charged into ion-exchanged water and washed repeatedly with water until the pH test paper became neutral. The obtained polymer was dried under reduced pressure at 80 ° C. overnight. The logarithmic viscosity of the obtained polymer in a methanesulfonic acid solution is 0.45 dl /
g. 0.08 g of the polymer was dissolved in 2.0 ml of methanesulfonic acid at room temperature. There, the logarithmic viscosity is 20
dl / g of poly {(benzo [1,2-d: 5,4-
d '] bisoxazole-2,6-diyl) -1,4-
2.00 g of a 1 wt% polyphosphoric acid solution of phenylene (phosphorus pentoxide content: 84%) was added and further stirred at room temperature to obtain a homogeneous solution. The solution was cast on a glass plate to a thickness of about 180 μm, allowed to stand for 10 minutes, and then immersed in water. The water was changed from time to time and the water immersion continued for several days. The film was taken out, air-dried while fixing the surroundings and suppressing shrinkage. Finally, the film was dried at 80 ° C. overnight using a reduced pressure drier to produce a film. TGA measurement of the obtained film showed that the 3% weight loss temperature was 377 ° C. 80 ° C 95%
The ionic conductivity at RH was 0.180 S / cm, and the measured ionic conductivity gradually decreased.

[0028]

According to the polymer of the present invention, it is possible to provide a material having excellent heat resistance and ionic conductivity and exhibiting outstanding durability as a polymer electrolyte for fuel cells and the like.

[Brief description of the drawings]

FIG. 1. IR spectrum of phosphonic acid-containing polybenzimidazole synthesized from TAS, DCP and TPA

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C08L 79:04 C08L 79:04 (72) Inventor Satoshi Takase 2-1-1 Katata, Otsu City, Shiga Prefecture No. Within Toyobo Co., Ltd. Research Laboratory (72) Inventor Shiro Hamamoto 2-1-1 Katada, Otsu-shi, Shiga Prefecture Within Toyobo Co., Ltd. Research Laboratory (72) Inventor Hiroshi Tatemori 2-1-1 Katata, Otsu-shi, Shiga Prefecture No. 1 Toyobo Co., Ltd. Research Laboratory F-term (reference) 4F071 AA60 AA81 AA83 AF02 AF13 AF37 AF37Y AF45 AF45Y BA02 BB02 BC01 4J043 PA02 PA08 PA10 QB34 QB35 QB41 RA42 RA52 RA57 SA06 SA08 SA71 SA83 SB01 SB03 TA12 UA121 TB03 TB12 UA132 UA142 UA262 UB021 UB061 UB062 UB121 UB122 UB301 UB302 VA011 VA012 VA041 VA042 VA061 VA062 VA081 VA082 XA03 XA19 ZA12 ZA15 ZA17 ZA31 ZA44 ZB 14 5G301 CA30 CD01 5H026 AA06 CX05 EE18 HH00 HH05 HH06 HH08

Claims (4)

[Claims] 1. The method according to claim 1, wherein the solution is 10,000 at 80 ° C. and 95% RH.
The conductivity obtained by measuring the AC impedance at 0 Hz is 0.001 [S / cm] or more, and the 3% weight loss temperature based on the sample weight at the time of 200 ° C. temperature rise in TGA measurement is 400%. C. or higher, the average molecular weight is between 1,000 and 1,000,000, and when a plurality of repeating units are present, the phosphonic acid-containing polyazole compound is mainly bonded randomly and / or alternately. . 2. 10,000 at 80 ° C. and 95% RH.
2. The compound according to claim 1, wherein the conductivity obtained by measuring the AC impedance at 0 Hz is 0.01 [S / cm] or more, and the main chain structure mainly comprises a polyoxazole skeleton. 3. A molded article characterized by comprising the compound according to claim 1 as a main component. 4. A film comprising the compound according to claim 1 as a main component.