JP5369401B2 - ION CONDUCTIVE POLYMER SUBSTANCE, PROCESS FOR PRODUCING THE SAME AND ION CONDUCTIVE POLYMER DERIVATIVE - Google Patents

Description

  The present invention relates to an ion conductive polymer material that can be suitably used for electrolyte membranes such as primary batteries, secondary batteries, fuel cells, display elements, various sensors, signal transmission media, solid capacitors, ion exchange membranes, and the like, and production thereof. The present invention relates to a method and an ion conductive polymer derivative obtained from the polymer substance.

  As a polymer belonging to a so-called cation exchange resin as an ion conductive polymer, polystyrene sulfonic acid, polyvinyl sulfonic acid, perfluorosulfonic acid polymer and the like have been reported. Since such a polymer material having a sulfonic acid group has a property of firmly binding to a specific ion or selectively permeating a cation or an anion, an electrodialysis membrane, a diffusion dialysis membrane, It is used for various applications such as battery diaphragms.

  Fluoropolymers having a sulfonic acid group in the side chain of the perfluoro skeleton known by the trademark Nafion (manufactured by DuPont) have excellent heat resistance and chemical resistance, and can withstand use under severe conditions. Practical use as a film. However, such a fluorine-based electrolyte membrane has a problem that it is very expensive because it is difficult to produce a fluorine-based polymer.

In the current proton-conducting membrane, water must be present as a substance that plays a role in proton transmission. Therefore, Nafion exhibits a high conductivity of 10 ⁻⁴ to 10 ⁻² S / cm at room temperature in a water-containing state. However, since the ion exchange capacity is as low as about 1.0 meq / g, it exhibits only low conductivity in the absence of water, and the proton conductivity is greatly affected by the water content in the membrane. have.

  That is, even when operating from room temperature to about 80 ° C. as in the present, the fact that water is essential is one of the major issues. In order for water to be present at all times, for example, fuel such as hydrogen needs to be sent in a humidified state. Therefore, the strict and complicated management of the amount of water in the membrane by such humidification itself is necessary. It is complicated and causes failure.

  Therefore, an electrolyte membrane using a polymer that has high conductivity in a water-containing state and high conductivity in a low humidity state and that can be manufactured at low cost using an environmentally safe solvent is desired. .

  Japanese Patent Application Laid-Open No. 2006-313659 (Patent Document 1) proposes a method for producing a polymer electrolyte membrane obtained by graft polymerization of a polymerizable monomer having an alkoxysilyl group in a molecule to a resin irradiated with radiation. . The electrolyte membrane made of this polymer is highly conductive, hydrolyzed and dehydrated by condensing this graft alkoxysilyl group, but is excellent in dimensional stability and methanol permeation prevention. There are many problems, and it is necessary to use a complicated and expensive apparatus such as an electron beam irradiation apparatus, and an inexpensive method for producing an electrolyte membrane has not been obtained. That is, a simple and inexpensive method for producing an electrolyte membrane having an alkoxysilyl group in the molecule is desired.

  Japanese Patent Laying-Open No. 2005-82768 (Patent Document 2) proposes a conductive composition in which an alkoxysilane derivative is mixed as an essential component with a water-soluble conductive polymer having a sulfonic acid group and / or a carboxyl group in the molecule. Yes. Although this membrane can produce a polymer compound with improved water resistance at a relatively low cost, it has a remarkably low electrical conductivity and is far below conventional electrolyte membranes. That is, further improvement is required for the conductivity of the electrolyte membrane.

  Japanese Unexamined Patent Publication No. 2006-100214 (Patent Document 3) discloses a copolymer of a monomer having a sulfonic acid group, a phosphonic acid group or a carboxyl group in the molecule and a basic monomer such as an amide group in the molecule, and a polyimide. The solid polymer electrolyte membrane which consists of is proposed. This copolymer uses an expensive and high boiling point solvent such as dimethyl sulfoxide (DMSO) as a polymerization solvent, and is inexpensive using an environmentally safe solvent for desirable polymer production. Therefore, a synthetic method that can be easily produced has been desired.

JP 2006-313659 A JP 2005-82768 A Japanese Patent Laid-Open No. 2006-100214

  The present invention has been made in view of the above circumstances, and provides film strength necessary for practical use in fuel cells and the like, and provides high conductivity in a water-containing state and also high conductivity in a low humidity state. It is an object of the present invention to provide an ion conductive polymer substance and a derivative thereof which can form an ion conductive film and can be manufactured at low cost using an environmentally safe solvent and a method for manufacturing the same.

  As a result of intensive studies to achieve the above object, the present inventors have obtained (A) an alkoxysilyl group-containing unsaturated monomer having an alkoxysilyl group and an ethylenically unsaturated bond, and (B) a sulfonic acid group. And an environmentally safe solvent by copolymerizing an unsaturated monomer containing a sulfonic acid group-containing unsaturated monomer having an ethylenically unsaturated bond with a lipophilic catalyst and a hydrophilic catalyst It was found that an ion conductive polymer material can be produced using Furthermore, it has been found that the obtained derivative of the ion conductive polymer substance is insoluble in water, has high proton conductivity, low humidity dependency of proton conductivity, and has high conductivity even in a low humidity state.

In other words, since this ion conductive polymer substance has an alkoxysilyl group, a flexible membrane can be formed by crosslinking by (partial) hydrolysis / condensation. Membranes made of polymer derivatives have practically sufficient membrane strength, and their ionic conductivity is remarkably large even at low humidity, so that they can exhibit excellent characteristics when used as a raw material for fuel cell electrolyte membranes. The headline and the present invention were made.
In addition, (partial) hydrolysis / condensation indicates that part or all of the alkoxysilyl group is hydrolyzed / condensed.

（式中、Ｒ¹は水素原子又はメチル基であり、Ｒ²，Ｒ³及びＲ⁴は水素原子又は置換もしくは非置換のアルキル基であり、ｍは１〜６の整数、ｎは１〜３の整数である。）
で示される分子内に１個以上のアルコキシシリル基と１個以上のエチレン性不飽和結合とを有するアルコキシシリル基含有不飽和モノマーと、
（Ｂ）２−アクリルアミド−２−メチルプロパンスルホン酸と
が共重合されてなり、１質量％ジメチルホルムアミド溶液のゲルパーミエーションクロマトグラフィーによるポリスチレン換算重量平均分子量が２０，０００〜１，０００，０００であることを特徴とするイオン伝導性高分子物質を提供する。
また、このイオン伝導性高分子物質のアルコキシシリル基の一部又は全部を加水分解・縮合することにより得られる水不溶性のイオン伝導性高分子誘導体を提供する。 Therefore, the present invention
(A) The following general formula (1)

Wherein R ¹ is a hydrogen atom or a methyl group, R ² , R ³ and R ⁴ are a hydrogen atom or a substituted or unsubstituted alkyl group, m is an integer of 1 to 6, and n is 1 to 3 Is an integer.)
An alkoxysilyl group-containing unsaturated monomer having one or more alkoxysilyl groups and one or more ethylenically unsaturated bonds in the molecule represented by
(B) 2-acrylamido-2-methylpropanesulfonic acid is copolymerized, and the weight average molecular weight in terms of polystyrene by gel permeation chromatography of a 1 mass% dimethylformamide solution is 20,000 to 1,000,000. There is provided an ion-conducting polymer material.
Also provided is a water-insoluble ion conductive polymer derivative obtained by hydrolyzing and condensing a part or all of the alkoxysilyl group of the ion conductive polymer substance.

  Conventionally, a polymer obtained by polymerizing an acid group-containing unsaturated monomer as a main component becomes water-soluble, so that when it is immersed in water, elution occurs, and there has been a technical problem that conductivity deteriorates over time. In the present invention, a monomer containing an alkoxysilyl group is copolymerized with a monomer containing a sulfonic acid group in order to prevent dissolution into water. This is because a monomer having a lipophilic silicon functional group (alkoxysilyl group) can be copolymerized with a hydrophilic acid group-containing monomer by using a lipophilic catalyst in combination with the hydrophilic catalyst.

  The ion conductive polymer material containing an alkoxysilyl group and a sulfonic acid group of the present invention obtained by such a production method can be dissolved in a suitable solvent such as an aliphatic lower alcohol during polymerization. After film formation, it is insolubilized in water by (partial) hydrolysis / condensation of alkoxysilyl groups and can be used as an electrolyte film. Moreover, since an aliphatic lower alcohol can be used as a solvent, it can manufacture safely on an environment.

  According to the present invention, a derivative of an ion conductive polymer substance that is effectively used as a proton conductive material can be obtained using the ion conductive polymer substance. The derivative of the ion conductive polymer material of the present invention is excellent in practically sufficient mechanical strength without using a reinforcing agent such as glass fiber.

The membrane made of the derivative of the ion conductive polymer material of the present invention is easy to manufacture and low in cost. In particular, when a phosphonic acid group-containing unsaturated monomer and a sulfonic acid group-containing unsaturated monomer are used in combination, high ion exchange Capacitance obtained, excellent proton conductivity with a conductivity of 10 ⁻³ to 10 ⁻¹ S / cm in a wide humidity range of 30 to 100% relative humidity, and small fluctuation in proton conductivity performance due to humidity change Can be obtained.
Therefore, it can be suitably used as a material for primary battery electrolytes, secondary battery electrolytes, fuel cell electrolytes, display elements, various sensors, signal transmission media, solid capacitors, ion exchange membranes, and the like.

The ion-conducting polymer substance, derivative thereof and production method thereof of the present invention will be described in detail.
[1] Raw Material for Ion Conductive Polymer Substance The ion conductive polymer substance of the present invention is (A) an alkoxysilyl having one or more alkoxysilyl groups and one or more ethylenically unsaturated bonds in the molecule. A polymer material obtained by copolymerizing a group-containing unsaturated monomer and (B) a sulfonic acid group-containing unsaturated monomer having one or more sulfonic acid groups and one or more ethylenically unsaturated bonds in the molecule. .
The introduction of component (A) is intended to insolubilize water and improve water resistance by (partially) hydrolyzing and condensing the alkoxysilyl group, and the introduction of component (B) is for ionic conductivity. Is.

(A) alkoxysilyl group-containing unsaturated monomer (A) alkoxysilyl group-containing unsaturated monomer having one or more alkoxysilyl groups and one or more ethylenically unsaturated bonds in the molecule Abbreviated as unsaturated monomer.

As the alkoxysilyl group, those having 1, 2 or 3 carbon atoms having 1 to 6 carbon atoms are preferable, trialkoxysilyl groups having a alkoxy group such as methoxy group, ethoxy group, propoxy group, butoxy group, dialkoxy. Examples include alkylsilyl groups and monoalkoxydialkylsilyl groups. In addition, as an alkyl group, a C1-C6 thing is mentioned.
Examples of the ethylenically unsaturated bond include a methacryloxy group and an acryloxy group. Examples of the alkoxysilyl group-containing unsaturated monomer include esters and amides having such a group, and a silane compound containing a (meth) acryloxy group or a (meth) acrylamide group is desirable.

  Examples of silane compounds containing a methacryloxy group or an acryloxy group include γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, Examples include γ-acryloxypropylmethyldimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropylmethyldiethoxysilane, and γ-acryloxypropyltriethoxysilane.

  Examples of silane compounds containing a methacrylamide group or an acrylamide group include γ-methacrylamideamidopropyldimethoxysilane, γ-methacrylamideamidotrimethoxysilane, γ-methacrylamidopropylmethyldiethoxysilane, and γ-methacrylamideamidopropyltriethoxysilane. Γ-acrylamidopropylmethyldimethoxysilane, γ-acrylamidopropyltrimethoxysilane, γ-acrylamidopropylmethyldiethoxysilane, γ-acrylamidopropyltriethoxysilane, and the like.

  The alkoxysilyl group-containing unsaturated monomer may be used alone or in combination of two or more. However, since it is copolymerized with the sulfonic acid group-containing unsaturated monomer, it is resistant to hydrolysis. A silane compound containing a (meth) acrylamide group is most desirable.

（式中、Ｒ¹は水素原子又はメチル基であり、Ｒ²，Ｒ³及びＲ⁴は水素原子又は置換もしくは非置換のアルキル基であり、ｍは１〜６の整数、ｎは１〜３の整数である。） In particular, the desirable structure of the (A) alkoxysilyl group-containing unsaturated monomer is represented by the following general formula (1).

Wherein R ¹ is a hydrogen atom or a methyl group, R ² , R ³ and R ⁴ are a hydrogen atom or a substituted or unsubstituted alkyl group, m is an integer of 1 to 6, and n is 1 to 3 Is an integer.)

In the above formula, examples of the substituted or unsubstituted alkyl group represented by R ^{2 to} R ⁴ include those having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group, butyl group, pentyl group, and hexyl group. It is done.

(B) Sulfonic acid group-containing unsaturated monomer (B) A sulfonic acid group-containing unsaturated monomer having one or more sulfonic acid groups and one or more ethylenically unsaturated bonds in the molecule is used in the present invention. Abbreviated as sulfonic acid group-containing unsaturated monomer.
Examples of the sulfonic acid group-containing unsaturated monomer include a sulfonic acid containing a styryl group, a methacryloxy group or an acryloxy group, a sulfonic acid group-containing methacrylamide derivative or an acrylamide derivative. The sulfonic acid group-containing unsaturated monomer is preferably a monomer having an amide bond that easily generates protons and that does not easily cleave.

  Illustrative compounds of unsaturated monomers containing sulfonic acid groups include vinyl sulfonic acid, p-styrene sulfonic acid, (meth) acrylic acid butyl-4-sulfonic acid, (meth) acrylooxybenzene sulfonic acid, 2-acrylamide. -2-methylpropane sulfonic acid (also known as tertiary butyl acrylamide sulfonic acid). P-styrene sulfonic acid and 2-acrylamido-2-methylpropane sulfonic acid are preferred, and 2-acrylamido-2-methylpropane sulfonic acid is particularly preferred, but the sulfonic acid group-containing unsaturated monomer that can be used in the present invention is It is not limited to these.

Other Acid Group-Containing Unsaturated Monomer The ion conductive polymer material of the present invention is produced by copolymerizing an acid group-containing component in a polymer. In addition to a sulfonic acid group as an acid group, phosphoric acid (phosphonic acid) Group) or an unsaturated monomer having a carboxylic acid group. Among them, the phosphonic acid group-containing unsaturated monomer (C) having one or more phosphonic acid groups and one or more ethylenically unsaturated bonds in the molecule has the second highest proton dissociation property after sulfonic acid and ion exchange. Capacitance can be increased and ion conductivity at low humidity can be increased.

  Examples of the unsaturated monomer containing a phosphonic acid group include a phosphate ester containing a methacryloxy group or an acryloxy group, a phosphonic acid group-containing methacrylamide derivative or an acrylamide derivative. Many phosphonic acid group-containing unsaturated monomers have a large ion exchange capacity reflecting the fact that phosphoric acid is a trivalent acid, and examples thereof include a phosmer series manufactured by Unichemical Corporation.

Examples of phosphate esters include acid phosphoxyethyl methacrylate (trade name: Phosmer M), 3-chloro-2-acid phosphoxypropyl methacrylate (trade name: Phosmer CL), and acid phosphoxypropyl methacrylate (trade name: Phosmer P). Acid phosphoxyethyl acrylate (trade name: Phosmer A), Acid phosphooxypolyoxyethylene glycol monomethacrylate (trade name: Phosmer PE), Acid phosphoxypolyoxypropylene glycol monomethacrylate (trade name: Phosmer PP), Methacryloyl Oxyethyl acid phosphate monoethanolamine half salt (trade name: Phosmer MH), methacryloyloxyethyl acid phosphate dimethylaminoethyl methacrylate half salt (trade) Name: Hosmer DM), methacryloyl oxyethyl acid phosphate Hastings preparative diethylaminoethyl methacrylate half Salt (trade name: Phosmer DE), and the like. As specific examples, CH ₂ = CHCOOCH ₂ CH ₂ OP (O) (OH) ₂ , CH ₂ = C (CH ₃ ) COOCH ₂ CH ₂ OP (O) (OH) ₂ , CH ₂ = C (CH _{3 ) COOCH 2 CH (CH 2 Cl} ) OP (O) (OH) 2, (CH 2 = CHCOOCH 2 CH 2 O) 2 P (O) OH, (CH 2 = C (CH 3) COOCH 2 CH 2 O) _{2 P (O) OH, CH} 2 = C (CH 3) CO (OCH 2 CH 2) 4 OP (O) (OH) 2, CH 2 = C (CH 3) CO (OCH 2 CH 2) 5 OP ( O) (OH) ₂ , CH ₂ ═C (CH ₃ ) CO (OCH ₂ CH (CH ₃ )) ₅ OP (O) (OH) ₂ and CH ₂ ═C (CH ₃ ) CO (OCH ₂ CH (CH ₃ )) ₆ OP (O) (OH) _{2 and the} like.

  Phosphonic acid group-containing (meth) acrylamide derivatives are most desirable because of their resistance to hydrolysis. Specific examples include methacrylamide phosphonic acid, acrylamide phosphonic acid, methacrylamide diphosphonic acid, acrylamide diphosphonic acid (acrylamide bisphosphate, trade name: Phosmer N2P), and the like. Two or more of these can be used as desired.

  Other unsaturated monomers containing an acidic group include unsaturated monomers containing a carboxyl group. Examples of such compounds include (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, maleic anhydride. A thing etc. are used suitably.

Mixing ratio The ratio of the above-mentioned (A) alkoxysilyl group-containing unsaturated monomer and (B) sulfonic acid group-containing unsaturated monomer is molar ratio ((B) sulfonic acid group-containing unsaturated monomer) / ((A) alkoxysilyl. Group-containing unsaturated monomer) = 100 / 0.1-100 / 50, more preferably ((B) sulfonic acid group-containing unsaturated monomer) / ((A) alkoxysilyl group-containing unsaturated monomer) = 100/1 to 100/10. When there are more alkoxysilyl group containing unsaturated monomers than this, it will become easy to gelatinize during superposition | polymerization, and there exists a possibility that electroconductivity may become inadequate, and when less than this, there exists a possibility that water resistance may worsen.

  There is no restriction | limiting in particular about the mixture ratio of a sulfonic acid group containing unsaturated monomer and another acid group containing unsaturated monomer, It can set arbitrarily. Since the sulfonic acid group-containing unsaturated monomer is a strong acid, the effect of improving conductivity can be promoted. Other acid group-containing unsaturated monomers, in particular phosphonic acid group-containing unsaturated monomers, can promote the improvement of conductivity under low humidity by improving the ion exchange capacity.

  Among the acid group-containing unsaturated monomers, (C) the phosphonic acid group-containing unsaturated monomer and (B) the sulfonic acid group-containing unsaturated monomer are used in a molar ratio ((C) phosphonic acid group-containing unsaturated monomer. ) / ((B) sulfonic acid group-containing unsaturated monomer) = 0/100 to 90/10, particularly when (B) component and (C) component are used in combination, the proportion of (C) component is ( The total amount of B) and (C) components is preferably more than 0 mol% and not more than 90 mol%, more preferably (C) / (B) = 1/99 to 90/10, still more preferably (C) / (B) = 20/80 to 80/20, most preferably about equimolar.

[2] Method for Producing Ion Conductive Polymer Substance The ion conductive polymer substance of the present invention can be produced by copolymerizing a mixture of the above monomers by radical polymerization.

(1) Polymerization method of copolymer The copolymer containing a sulfonic acid group and an alkoxysilyl group has an alkoxysilyl group-containing monomer that is lipophilic and a sulfonic acid group-containing monomer that is hydrophilic. Copolymerization is difficult when using industrially-used solvents such as alcohol, especially when coexisting with a monomer having an alkoxysilyl group, gelation and association are likely to occur during polymerization, making the solvent insoluble. Therefore, it is generally difficult to manufacture industrially.
Therefore, in the present invention, by employing a polymerization method in which a hydrophilic polymerization catalyst and a lipophilic polymerization catalyst are used in combination, it is possible to carry out copolymerization without generating a gel. The polymerization reaction is preferably performed in a common solvent in which both the unsaturated monomer and the resulting copolymer are dissolved.

  As lipophilic polymerization catalysts, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2′-azobis (2-methylpropionate) , Azo initiators such as dimethyl 2,2′-azobisisobutyrate, or initiators composed of peroxide ethers or peroxide ester compounds such as lauryl peroxide, benzoyl peroxide, tert-butyl peroxy pivalate, etc. Is mentioned.

  Examples of hydrophilic polymerization catalysts include polymerization initiators of peroxides such as peroxydisulfate salts such as ammonium peroxydisulfate, peracids such as peracetic acid, and peralcohols such as tert-butyl hydroperoxide. Etc.

  There is no restriction | limiting in particular about the blending ratio of a hydrophilic polymerization catalyst and a lipophilic polymerization catalyst, It can set arbitrarily, and it shall be hydrophilic polymerization catalyst / lipophilic polymerization catalyst = 90/10-10/90 (mass ratio). However, radical polymerization is usually performed using an equal mass.

  The polymerization procedure is described. First, in a reactor equipped with a stirrer and a reflux condenser, a solution composed of the above-mentioned various unsaturated monomers and a solvent is charged, and the temperature is raised to 40 ° C to 90 ° C, preferably 50 ° C to 80 ° C. Immediately after reaching the predetermined temperature, a polymerization initiator (hydrophilic polymerization catalyst and lipophilic polymerization catalyst) is added. At this time, there is slight heat generation, and the start of polymerization can be confirmed. The polymerization reaction is continued for about 1 to 10 hours after reaching the predetermined temperature. The reaction temperature does not need to be constant from the beginning to the end, and a method of increasing the temperature at the end of the polymerization to minimize the unreacted monomer may be employed.

  As the solvent, aliphatic lower alcohols and amides are used. Specific examples include alcohols such as methanol, ethanol and isopropyl alcohol, and amides such as dimethylformamide and dimethylacetamide. Ethanol is preferable. Two or more of these may be used in combination. Moreover, when it can use together, you may coexist solvent, such as ester. When an aliphatic lower alcohol is used as a solvent, it can be produced inexpensively and environmentally safely.

In the polymerization solution, the initial concentration of the unsaturated monomer component is preferably 5 to 50% by mass, and more preferably 10 to 35% by mass.
The total amount of the polymerization initiator (hydrophilic polymerization catalyst and lipophilic polymerization catalyst) is preferably 0.005 to 0.05 in terms of mass ratio when the monomer component is 1, and 0.01 to 0.00. 03 is more preferable.
If the initial concentration of the unsaturated monomer component in the polymerization solution and the amount of the polymerization initiator used are not within the above preferred ranges, the copolymer may gel and become insoluble in various solvents. This polymer can be used by mixing with other resins and the like, but it may not be possible to form a uniform composition with such a resin.

  The solution after the reaction is preferably purified in order to remove unreacted monomers and the like. The purification is performed by concentrating the polymer solution until the solid content concentration becomes 10 to 80% by mass, then depositing the concentrated solution into a poor solvent to precipitate a solid, and removing the poor solvent by a decantation method. . As the poor solvent, ketones such as acetone, methyl ethyl ketone, and methyl butyl ketone are preferable. The poor solvent is preferably used in a large excess amount of 2 to 15 times the solid volume of the reaction product. What is necessary is just to repeat the washing | cleaning operation of the solid by a poor solvent as needed.

  When the film is formed as it is, the solid made of the copolymer obtained by washing with a poor solvent can be dissolved again in a good solvent to form a solution. The good solvent is preferably the same aliphatic lower alcohol used during the polymerization reaction, more preferably ethanol.

The ion conductive polymer substance, which is a copolymer containing a sulfonic acid group and an alkoxysilyl group, obtained by such a method can be obtained as a polymer solution or a solid. Usually, it is preferable that the degree of polymerization is such that the viscosity (25 ° C.) becomes 2 to 50 mPa · s when the copolymer solid content concentration is 20% by mass in a methanol solution. In the present invention, the viscosity can be measured with an Ostwald viscometer (capillary viscometer devised by FW Ostwald).
In this case, the polystyrene-equivalent weight average molecular weight of the 1% by mass dimethylformamide (DMF) solution by gel permeation chromatography (GPC) is 10,000 to 1,000,000, particularly 10,000 to 100,000. Is preferred.

  The present invention further provides an ion conductive polymer derivative obtained by (partial) hydrolysis / condensation of the above ion conductive polymer substance. Here, the ion conductive polymer derivative is obtained by hydrolyzing and condensing a part or all of the alkoxysilyl group of the ion conductive polymer substance. ) It is water-insoluble consisting of hydrolysis / condensation product.

  That is, the ion conductive polymer substance of the present invention can be rendered water-insoluble by hydrolyzing and condensing part or all of the alkoxysilyl group. Hydrolysis / condensation of the alkoxysilyl group may be part or all, but in some cases, the hydrolysis / condensation ion-conducting polymer material needs to be insoluble in water.

  Here, the (partial) hydrolysis / condensation of the ion conductive polymer substance can be carried out by a conventional method of (partial) hydrolysis / condensation of the trialkoxysilyl group according to a known method, in the presence of water. It can be carried out under acidic or basic conditions. In this case, since the ion conductive polymer substance has a sulfonic acid group, it is acidic per se, and thus easily hydrolyzes / condenses in the presence of water. However, it accelerates the hydrolysis / condensation rate. Alternatively, in order to promote the degree of hydrolysis / condensation, an acid such as sulfuric acid may be added. Ammonium salt, amine salt, alkali metal salt of sulfonic acid may be added by adding ammonia, amine, or alkali hydroxide. Etc., and hydrolysis / condensation may be carried out under basic conditions.

  Further, if necessary, a known condensation reaction catalyst such as tin dioctoate, dimethyltin diversate, dibutyldimethoxytin, dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin dibenzyl malate, dioctyltin dilaurate , Tin catalysts such as tin chelates, strong base compounds such as guanidine, DBU (1,8-diazabicyclo [5.4.0] -7-undecene) and alkoxysilanes having these groups, tetraisopropoxy titanium, tetra- A catalytic amount of titanic acid ester or titanium chelate compound such as n-butoxytitanium, tetrakis (2-ethylhexoxy) titanium, dipropoxybis (acetylacetona) titanium, titanium isopropoxyoctylene glycol, etc. It can be added 0.01 to 10 parts by mass) with respect to emission conductive polymer material 100 parts by weight.

  In the case of forming a film of the ion conductive polymer substance or its derivative, the film formation can be produced by applying the polymer solution as it is or by applying or impregnating the reinforcing material sheet and evaporating the solvent. It is preferable to produce by evaporating the solvent and further heating to 50 ° C to 130 ° C. In this case, in order to (partially) hydrolyze and condense the alkoxysilyl group to obtain a derivative film, moisture in the air can be used, and preferably, the relative humidity is RH 30 to 100%, particularly 40 to 95%. It can be left for 1 to 24 hours, in particular 1 to 5 hours.

  Furthermore, the film | membrane with improved electroconductivity is obtained by immersing this film | membrane in acidic aqueous solution. That is, when immersed in an acidic aqueous solution, almost all alkoxy groups are hydrolyzed / condensed, and can be changed to SiOSi via a hydroxysilyl group (silanol group). At the same time, when the sulfonic acid group of the ion conductive polymer substance or its derivative forms an ammonium salt, an amine salt, an alkali metal salt or the like, the acid group is regenerated in the film, and the conductivity is improved. Examples of the acidic solution include a phosphoric acid aqueous solution, a hydrochloric acid aqueous solution, and a sulfuric acid aqueous solution. The concentration of the acidic solution is preferably 0.05 to 5N. The immersion temperature is preferably 15 ° C. to 35 ° C., and the immersion time is preferably 1 to 60 minutes.

Such a film of an ion conductive polymer derivative containing a sulfonic acid group and an alkoxysilyl group exhibits excellent proton conductivity of 10 ⁻⁷ to 10 ⁻⁴ S / cm even at low humidity. In the present invention, the conductivity can be measured by an AC impedance method using an impedance analyzer.

  The thickness of the ion conductive polymer derivative film of the present invention is not particularly limited, but is preferably 1 to 1,000 μm, more preferably 10 to 500 μm.

The ion conductive polymer derivative membrane of the present invention has excellent proton conductivity with a conductivity of 10 ⁻³ to 10 ⁻¹ S / cm at a relative humidity of 100%, and the temperature dependence of such proton conductivity is small. . In particular, when an acid group-containing unsaturated monomer is used in combination with a sulfonic acid group-containing unsaturated monomer and a phosphonic acid group-containing unsaturated monomer, a monomer containing acrylamide-2-methyl-1-propanesulfonic acid and phosmer N2P is used. The conductivity of the ion-conductive polymer derivative film, which is a polymer, is on the order of 10 ⁻³ S / cm at a relative humidity of 30%, and is excellent in proton conductivity at low humidity.

  The ion conductive polymer derivative membrane of the present invention comprises a hydrophobic part composed of a siloxane skeleton derived from an alkoxysilyl group and a hydrocarbon skeleton derived from an ethylenically unsaturated bond, and a hydrophilic part composed of a sulfonic acid group or a phosphonic acid group. It is presumed to have a structure divided into two. In particular, when a sulfonic acid group-containing unsaturated monomer and a phosphonic acid group-containing unsaturated monomer are used in combination, the ion conductive polymer derivative membrane of the present invention has a very high ion exchange capacity of 8 times or more that of a Nafion membrane, and has a low Since protons can efficiently conduct along acid groups from acid groups in the polymer under humidity conditions, it is considered that conductivity can be exhibited even at low humidity with little moisture.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In addition, in the following example, a viscosity shows the value in 25 degreeC.

[Synthesis of raw material polymer]
According to the charged composition shown in Table 1, copolymers were prepared using various polymerization catalysts.

(Example 1, Comparative Examples 1 and 2)
(1) (Example 1) Production and evaluation of physical properties of copolymer 1 3-triethoxysilylpropylacrylamide (KBE-AA) was connected to a reactor connected to a reflux condenser, a dropping funnel, a thermometer, and a nitrogen gas introduction pipe. 11 g (2 mol%), 2-acrylamido-2-methylpropanesulfonic acid (AASO3H) 385 g (97 mol%), and ethanol (EtOH) 4,500 g were added and stirred while introducing nitrogen gas. The temperature was raised to 80 ° C., the polymerization temperature.

After confirming that the internal temperature reached 78 ° C. of ethanol reflux temperature, a 10% by mass EtOH solution of 2,2′-azobis (2-methylbutyronitrile) (V-59) and ammonium peroxydisulfate A 10% by mass DMF solution of ((NH ₄ ) ₂ S ₂ O ₈ ) was added in an amount of 0.5% by mass with respect to the total mass of the monomer so that the total amount was 1% by mass. At this time, a slight polymerization exotherm occurred and the start of polymerization was confirmed. Polymerization was performed for 6 hours to obtain an EtOH solution containing a copolymer.

The obtained EtOH solution was put in an aluminum petri dish, placed in an oven at 105 ° C. for 3 hours, measured for non-volatile content, made 1% by mass DMF solution, measured for molecular weight distribution by GPC, and measured for solution viscosity by Ostwald method. A high molecular weight product with a small amount was obtained.
From the solution obtained from Example 1, the area area with a weight average molecular weight of 20,000 and a molecular weight of 300 or less considered to be a residual monomer that was not polymerized was 6%, and it was considered that the polymerization proceeded well. It is done.

  Further, the ion exchange capacity was measured by neutralizing and titrating this solution with 0.1N sodium hydroxide (f = 0.999) using phenolphthalein as an indicator.

The obtained copolymer solution was cast on a polytetrafluoroethylene sheet, placed in an air flow dryer, completely removed the solvent at 80 ° C., and then left in a room with a humidity of 43% for 24 hours. Thus, a film made of a polymer derivative not dissolved in water having a film thickness of 255 μm was produced.
An evaluation cell was prepared by sandwiching the obtained thin film between stainless steel electrodes plated with gold, and ionic conductivity was measured by an AC impedance method (LCR Hitester manufactured by Hioki Electric Co., Ltd., measurement frequency 0.1 Hz to 5 MHz). When the conductivity was measured by leaving it in a room with a humidity of 43% for 24 hours, a value of 2.5 × 10 ⁻⁷ S / cm was obtained. Next, when immersed in a 1N sulfuric acid aqueous solution for 2 hours and removing moisture on the surface, the conductivity was measured. As a result, a value of 7.5 × 10 ⁻³ S / cm was obtained. Furthermore, after the film was heated at 80 ° C. for 1 hour to remove moisture, it was left to stand in a room with a humidity of 50% for 24 hours, and the conductivity was measured to find 3.5 × 10 ⁻⁵ S / cm. A value was obtained.

(2) (Comparative Example 1) Production of Copolymer 1 and Evaluation of Physical Properties For comparison, the polymerization catalyst was 2,2′-azobis (2-methylbutyronitrile) (under the same polymerization conditions as in Example 1). Instead of only V-59), it was charged so as to be 1% by mass relative to the total mass of the monomers. At this time, the start of polymerization was confirmed, and polymerization was performed for 6 hours to obtain an EtOH solution containing a copolymer.
The polymer obtained from this solution had a weight average molecular weight of 5,700 and polymerization did not proceed well up to a high molecular weight. Therefore, the obtained film was brittle and the conductivity could not be measured.

(3) (Comparative Example 2) Production of Copolymer 1 and Evaluation of Physical Properties For comparison, the polymerization catalyst was ammonium peroxydisulfate ((NH ₄ ) ₂ S ₂ O under the same polymerization conditions as in Example 1. Instead of only ₈ ), it was charged so as to be 1% by mass relative to the total mass of the monomers. At this time, the start of polymerization was confirmed, and polymerization was performed for 6 hours to obtain an EtOH solution containing a copolymer.

This solution contains 54% area area with a molecular weight of 300 or less, which is considered to be a residual monomer, and it is considered that the polymerization did not proceed well. When this membrane was left in a room with a humidity of 43% for 24 hours and the ionic conductivity was measured, a value of 4.4 × 10 ⁻⁶ S / cm was obtained. Next, when immersed in a 1N aqueous sulfuric acid solution for 2 hours, the membrane was broken and ionic conductivity could not be measured.

( Reference Example 1 and Comparative Example 3)
(4) ( Reference Example 1 ) Production of Copolymer 2 and Evaluation of Physical Properties 3-Triethoxysilylpropylacrylamide (KBE-AA) was connected to a reactor connected with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen gas introduction pipe. 22 g (2 mol%), 2-acrylamido-2-methylpropanesulfonic acid (AASO3H) 392 g (48.5 mol%), acrylamide bisphosphate (manufactured by Unichemicals; Phosmer N2P) 444 g (48.5 mol%), ethanol (EtOH) 4,500g was added, it stirred, introducing nitrogen gas, and the temperature of the oil bath was heated up to 80 degreeC used as polymerization temperature.

After confirming that the internal temperature reached 78 ° C. of ethanol reflux temperature, a 10% by mass EtOH solution of 2,2′-azobis (2-methylbutyronitrile) (V-59) and ammonium peroxydisulfate A 10% by mass DMF solution of ((NH ₄ ) ₂ S ₂ O ₈ ) was added in an amount of 0.5% by mass with respect to the total mass of the monomer so that the total amount was 1% by mass. At this time, a slight polymerization exotherm occurred and the start of polymerization was confirmed. Polymerization was performed for 6 hours to obtain an EtOH solution containing a copolymer.

The obtained EtOH solution was placed in an aluminum petri dish, placed in an oven at 105 ° C. for 3 hours, measured for nonvolatile content, 1% by mass DMF solution, molecular weight distribution measurement by GPC, and solution viscosity measurement by Ostwald method. A high molecular weight product with less monomer was obtained.
From this solution, the area area with a weight average molecular weight of 68,000 and a molecular weight of 300 or less considered to be a residual monomer that was not polymerized was 3%, and the polymerization was considered to have proceeded well.

The obtained copolymer solution was cast on a polytetrafluoroethylene sheet, placed in an air flow dryer, heated from room temperature to 80 ° C. to completely remove the solvent, and then indoors with a humidity of 43%. For 24 hours to prepare a film made of a polymer derivative that does not dissolve in water having a film thickness of 135 μm.
This film was left in a room with a humidity of 43% for 24 hours and measured for ionic conductivity in the same manner as in Example 1. As a result, a value of 4.3 × 10 ⁻⁴ S / cm was obtained. Next, it was immersed in a 1N sulfuric acid aqueous solution for 2 hours, and after removing moisture on the surface, the conductivity was measured. As a result, a value of 6.7 × 10 ⁻² S / cm was obtained. Further, after the film was heated at 80 ° C. for 1 hour to remove moisture, the film was left in a room with a humidity of 50% for 24 hours, and the conductivity was measured to find 1.3 × 10 ⁻³ S / cm. A value was obtained.

(5) (Comparative Example 3) Production and Evaluation of Physical Properties of Copolymer 2 For comparison, the polymerization catalyst was ammonium peroxydisulfate ((NH ₄ ) ₂ S ₂ O under the same experimental conditions as in Reference Example 1. Instead of only ₈ ), it was charged so as to be 1% by mass relative to the total mass of the monomers. At this time, the start of polymerization was confirmed, and polymerization was performed for 6 hours to obtain an EtOH solution containing a copolymer.
The polymer obtained from this solution had a weight average molecular weight of 46,000 and an area area of 300% or less, which is considered to be a residual monomer, contained 32%, and it is considered that the polymerization did not proceed well.

(Comparative Example 4)
(6) (Comparative Example 4) Production of Copolymer 3 and Evaluation of Physical Properties Copolymerization was conducted using the polymerization catalyst and polymerization conditions of Example 1 without using only KBE-AA. This product could be formed into a film by drying in an oven, but it was water-soluble and dissolved in water to form a solution. A film was formed from this solution, and an attempt was made to measure the conductivity, but it could not be measured due to cracking.

(Comparative Example 5)
(7) (Comparative Example 5) Production and property evaluation of copolymer 4
Copolymerization was performed using the polymerization catalyst of Reference Example 1 and polymerization conditions without using only KBE-AA. This product could be formed into a film by drying in an oven, but it was water-soluble and dissolved in water to form a solution.

( Reference Example 2 )
(8) ( Reference Example 2 ) Production of Copolymer 5 and Evaluation of Physical Properties 3-Triethoxysilylpropylacrylamide (KBE-AA) was connected to a reactor connected to a reflux condenser, a dropping funnel, a thermometer, and a nitrogen gas introduction pipe. 44 g (4 mol%), 2-acrylamido-2-methylpropanesulfonic acid (AASO3H) 392 g (48.5 mol%), acrylamide bisphosphate (manufactured by Unichemical; Phosmer N2P), 444 g (48.5 mol%), Ethanol (EtOH) 4,500 g was added and stirred while introducing nitrogen gas, and the temperature of the oil bath was raised to 80 ° C., which is the polymerization temperature.

After confirming that the internal temperature reached 78 ° C. of ethanol reflux temperature, a 10% by mass EtOH solution of 2,2′-azobis (2-methylbutyronitrile) (V-59) and ammonium peroxydisulfate A 10% by mass DMF solution of ((NH ₄ ) ₂ S ₂ O ₈ ) was added in an amount of 0.5% by mass with respect to the total mass of the monomer so that the total amount was 1% by mass. At this time, a slight polymerization exotherm occurred and the start of polymerization was confirmed. Polymerization was performed for 6 hours to obtain an EtOH solution containing a copolymer.

The obtained EtOH solution was placed in an aluminum petri dish, placed in an oven at 105 ° C. for 3 hours, measured for nonvolatile content, 1% by mass DMF solution, molecular weight distribution measurement by GPC, and solution viscosity measurement by Ostwald method. A high molecular weight product with less monomer was obtained.
From the solution obtained from Reference Example 2, the area area with a weight average molecular weight of 69,000 and a molecular weight of 300 or less, which is considered to be a residual monomer that was not polymerized, was 3%, and the polymerization was considered to proceed well. It is done.

The obtained copolymer solution was cast on a polytetrafluoroethylene sheet, placed in an air flow dryer, heated from room temperature to 80 ° C. to completely remove the solvent, and then indoors with a humidity of 43%. For 24 hours to prepare a film made of a polymer derivative that does not dissolve in water having a film thickness of 135 μm.
This membrane was left in a room with a humidity of 43% for 24 hours, and the ionic conductivity was measured in the same manner as in Example 1. As a result, a value of 1.3 × 10 ⁻⁵ S / cm was obtained. Next, it was immersed in a 1N sulfuric acid aqueous solution for 2 hours, and after removing moisture on the surface, the conductivity was measured. As a result, a value of 1.1 × 10 ⁻¹ S / cm was obtained. Further, after the film was heated at 80 ° C. for 1 hour to remove moisture, the film was left in a room with a humidity of 50% for 24 hours, and the conductivity was measured to find 1.2 × 10 ⁻³ S / cm. A value was obtained.

＊ 触媒：Ｍｉｘ＝Ｖ−５９＋（ＮＨ₄）₂Ｓ₂Ｏ₈（等質量）
＊＊ 架橋剤量：ポリマー中のＫＢＥ−ＡＡの割合
＊＊＊重量平均分子量：Ｍｗ（１質量％ＤＭＦ溶液のＧＰＣによる測定）

* Catalyst: Mix = V−59 + (NH ₄ ) ₂ S ₂ O ₈ (equal mass)
** Crosslinking agent amount: ratio of KBE-AA in polymer ** Weight average molecular weight: Mw (measured by GPC of 1 mass% DMF solution)

Notes: (1) KBE-AA: 3-triethoxysilylpropylacrylamide.
(2) AASO3H: 2-acrylamido-2-methylpropanesulfonic acid.
(3) (NH ₄ ) ₂ S ₂ O ₈ : ammonium peroxydisulfate.
(4) V-59: 2,2′-azobis (2-methylbutyronitrile).
(5) Phosmer N2P: acrylamide bisphosphate.
(6) DMF: Dimethylformamide.

Solution viscosity:
The solution viscosity at 25 ° C. was measured with an Ostwald viscometer of 10-23 mass% (nonvolatile content) EtOH solution.
Nonvolatile content:
A certain amount was weighed in an aluminum petri dish, placed in an oven at 105 ° C. for 3 hours, and determined from the decrease in mass.
Film thickness:
Measured with Mitsutoyo thickness gauge (ID C112B).
Conductivity (after acid treatment):
After immersing in 1N H ₂ SO ₄ , the H ₂ SO ₄ solution was thoroughly wiped off, heated at 80 ° C. for 1 hour to remove moisture in the film, and then left to stand at a humidity of 50% RH for 24 hours.

＊ 触媒：Ｍｉｘ＝Ｖ−５９＋（ＮＨ₄）₂Ｓ₂Ｏ₈（等質量）
＊＊ 架橋剤量：ポリマー中のＫＢＥ−ＡＡの割合
＊＊＊重量平均分子量：Ｍｗ（１質量％ＤＭＦ溶液のＧＰＣによる測定）

* Catalyst: Mix = V−59 + (NH ₄ ) ₂ S ₂ O ₈ (equal mass)
** Crosslinking agent amount: ratio of KBE-AA in polymer ** Weight average molecular weight: Mw (measured by GPC of 1 mass% DMF solution)

From the results shown in Tables 1 and 2 , the films of Example 1 and Reference Examples 1 and 2 are both in the order of conductivity of 10 ⁻³ to 10 ⁻¹ S / cm at 100% relative humidity after treatment with acid. Met. Further, the electrical conductivity at a relative humidity of 50% is on the order of 10 ⁻⁵ to 10 ⁻³ S / cm, and in particular, a polymer film containing both phosphate groups and sulfonic acid groups is 10 ⁻³ S / cm. It can be seen that the electrolyte material is in a good level on the order of.

  By comparing the comparative example and the example, the film made of the derivative of the ion conductive polymer material of the present invention has practical strength as a film without using a reinforcing material such as glass fiber, and has a low humidity. It can be seen that excellent ionic conductivity is exhibited even in the environment.

Claims (2)

(A) The following general formula (1)

Wherein R ¹ is a hydrogen atom or a methyl group, R ² , R ³ and R ⁴ are a hydrogen atom or a substituted or unsubstituted alkyl group, m is an integer of 1 to 6, and n is 1 to 3 Is an integer.)
An alkoxysilyl group-containing unsaturated monomer having one or more alkoxysilyl groups and one or more ethylenically unsaturated bonds in the molecule represented by
(B) 2-acrylamido-2-methylpropanesulfonic acid is copolymerized, and the weight average molecular weight in terms of polystyrene by gel permeation chromatography of a 1 mass% dimethylformamide solution is 20,000 to 1,000,000. An ion-conducting polymer material characterized by being.   A water-insoluble ion conductive polymer derivative obtained by hydrolyzing and condensing a part or all of the alkoxysilyl group of the ion conductive polymer material according to claim 1.