JP4467387B2 - Solid polymer electrolyte membrane for direct methanol solid polymer fuel cell - Google Patents

Description

The present invention is excellent in solvent resistance and water resistance, relates to a solid polymer electrolyte membrane for direct methanol solid polymer fuel cell showing a high proton conductivity over a wide temperature range and humidity range.

  Polymers belonging to so-called cation exchange resins such as polystyrene sulfonic acid, polyvinyl sulfonic acid, perfluorosulfonic acid polymer, perfluorocarboxylic acid polymer [Polymer Preprints, Japan Vol. 42, No. 7, pp. 2490-2492 (1993), Polymer Preprints, Japan Vol. 43, No. 3, pp. 735-736 (1994), Polymer Preprints, Japan Vol. 42, No. 3, p. 730 (1993)] etc. Has been reported.

  In particular, a solid polymer material having a sulfonic acid group in the side chain has a property of binding firmly to a specific ion or selectively transmitting a cation or an anion. It is formed into a shape or a membrane and is used in various applications such as electrodialysis membranes, diffusion dialysis membranes, and battery membranes. Above all, a fluoropolymer electrolyte membrane having a sulfonic acid group in the side chain of the perfluoro skeleton known by the trademark Nafion (manufactured by DuPont) is excellent in heat resistance and chemical resistance, and can be used under severe conditions. It has been put to practical use as an electrolyte membrane that can withstand use. However, the fluorine-based electrolyte membrane as described above has a problem that it is very expensive.

  Under such circumstances, JP-A-2003-86021 discloses a phosphate group-containing unsaturated monomer having at least one phosphate group and at least one ethylenically unsaturated bond in the molecule, and 1 in the molecule. A solid polymer electrolyte membrane comprising a copolymer of at least one sulfonic acid group and a sulfonic acid group-containing unsaturated monomer having at least one ethylenically unsaturated bond is proposed. The solid polymer electrolyte membrane disclosed in Japanese Patent Application Laid-Open No. 2003-86021 can be manufactured at a relatively low cost, and has a high conductivity, a low temperature dependence of conductivity, and excellent heat resistance and solvent resistance. It was in line with the solid polymer material.

  However, when a solid polymer electrolyte membrane is used in a fuel cell, particularly a direct methanol solid polymer fuel cell, a fuel composed of methanol and water is directly supplied to a fuel electrode provided on one surface of the solid polymer electrolyte membrane. In addition to conductivity, solvent resistance and water resistance are required. On the other hand, Japanese Patent Application Laid-Open No. 2003-138088 (Patent Document 1) discloses a solid polymer electrolyte obtained by heating a polymer of a phosphate group-containing unsaturated monomer and a polyamide resin. The solid polymer electrolyte disclosed in Patent Document 1 can be manufactured at a relatively low cost, and is excellent in conductivity, solvent resistance, and water resistance.

JP2003-138088

  However, solid polymer electrolyte membranes for fuel cells are required to further improve conductivity, solvent resistance and water resistance.

Accordingly, an object of the present invention is a direct methanol solid polymer fuel that can be produced at a relatively low cost, has high proton conductivity in a wide temperature range and humidity range, and has excellent solvent resistance and water resistance. It is to provide a solid polymer electrolyte membrane for a battery .

As a result of diligent research in view of the above object, the present inventors have obtained (a) a phosphate group-containing unsaturated monomer having at least one phosphate group and one or more ethylenically unsaturated bonds in the molecule, and (b) At least one hydrogenated conjugated diene-based liquid oligomer selected from the group consisting of a hydrogenated butadiene oligomer having at least one hydrocarbon group having an ethylenically unsaturated bond in each molecule, a hydrogenated isoprene oligomer, and derivatives thereof; Copolymerization of a solid polymer electrolyte membrane for direct methanol solid polymer fuel cells with high proton conductivity in a wide range of temperature and humidity, and excellent solvent resistance and water resistance As a result, the present invention has been conceived.

で表される繰り返し単位（ただしR ₁ 及びR ₂ はそれぞれ独立に水素基又はメチル基であり、かつR ₁ 及びR ₂ の少なくとも一方は水素基である）で構成された重合体鎖、式(1b)：

で表され、前記重合体鎖の一方の末端に結合した構造単位（ただしR ₁ 及びR ₂ は式(1a)と同じであり、R ₃ は(i) エチレン性不飽和結合を１個以上有し、かつ他の原子団を有してもよい炭化水素基、(ii) エチレン性不飽和結合を有さず、かつ他の原子団を有してもよい炭化水素基又は(iii) 水素基である）、及び式(1c)：

で表され、前記重合体鎖の他方の末端に結合した構造単位（ただしR ₁ 及びR ₂ は式(1a)と同じであり、R ₄ は(i) エチレン性不飽和結合を１個以上有し、かつ他の原子団を有してもよい炭化水素基、(ii) エチレン性不飽和結合を有さず、かつ他の原子団を有してもよい炭化水素基又は(iii) 水素基である）からなり、かつ前記R ₃ 及びR ₄ の少なくとも一方は前記(i) エチレン性不飽和結合を有する炭化水素基であり、数平均分子量が500〜50,000である水素化共役ジエン系液状オリゴマー
とを共重合してなることを特徴とする。
That is, the solid polymer electrolyte membrane for direct methanol solid polymer fuel cell of the present invention has at least
(a) a phosphate group-containing unsaturated monomer having at least one phosphate group and at least one ethylenically unsaturated bond in the molecule;
(b) Formula (1a):

A polymer chain comprising a repeating unit represented by the formula ( wherein R ₁ and R ₂ are each independently a hydrogen group or a methyl group, and at least one of R ₁ and R ₂ is a hydrogen group): 1b):

And a structural unit bonded to one end of the polymer chain (where R ₁ and R ₂ are the same as in formula (1a), and R ₃ has (i) one or more ethylenically unsaturated bonds) And (ii) a hydrocarbon group that does not have an ethylenically unsaturated bond and may have another atomic group, or (iii) a hydrogen group And formula (1c):

And a structural unit bonded to the other end of the polymer chain (where R ₁ and R ₂ are the same as in formula (1a), and R ₄ has (i) one or more ethylenically unsaturated bonds) And (ii) a hydrocarbon group that does not have an ethylenically unsaturated bond and may have another atomic group, or (iii) a hydrogen group And at least one of R ₃ and R ₄ is (i) a hydrocarbon group having an ethylenically unsaturated bond, and a number average molecular weight of 500 to 50,000 is a hydrogenated conjugated diene-based liquid oligomer And is copolymerized.

  The blending ratio of the (a) phosphate group-containing unsaturated monomer and the (b) hydrogenated conjugated diene-based liquid oligomer is expressed by the formula [((a) phosphate group-containing unsaturated monomer) / (above (b) Hydrogenated conjugated diene-based liquid oligomer)] is preferably in the range of 99/1 to 40/60.

（ただしR ₅ はH又はCH ₃ であり、R ₆ はH、CH ₃ 又はCH ₂ Clであり、nは１〜６の整数である。）により表される化合物を含むのが好ましい。
The phosphate group-containing unsaturated monomer has the following general formula ( 2 ):

(Wherein R ₅ is H or CH _3, R ₆ is H, CH ₃ or CH ₂ Cl, n is an integer of 1-6.) Preferably contains a compound represented by the.

The solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell according to the present invention comprises (a) a phosphate group-containing unsaturated monomer , (b) a hydrogenated conjugated diene-based liquid oligomer , and (c) ) It may be formed by copolymerization with unsaturated monomers other than (a) and (b) . (C) is (c-1) (i) at least one functional group selected from the group consisting of an ethylenically unsaturated bond and (ii) a sulfonic acid group, a carboxylic acid group, an alcoholic hydroxyl group and an amino group. And (c-2) having at least one ethylenically unsaturated bond in the molecule, but having a sulfonic acid group, a carboxylic acid group, an alcoholic hydroxyl group, and Does not have any amino group, and (meth) acrylonitrile, (meth) acrylic acid esters, substituted or unsubstituted styrenes, vinyl chloride, vinyl acetate, and one or more fluorine groups and one or more in the molecule And at least one unsaturated monomer selected from the group consisting of fluorine-containing unsaturated monomers having an ethylenically unsaturated bond, or both of them. The mass ratio of (a) to (c) is preferably 20/80 or more. The mass ratio of (c-1) to (c-2) is preferably (100/0) to (50/50).

（ただしR₇及びR₁₀はそれぞれ独立にH又はCH ₃ であり、R₈及びR₉はそれぞれ独立にH、CH ₃ 又はCH ₂ Clであり、k及びpはそれぞれ独立に１〜６の整数である。）により表されるリン酸基含有ジエステル系不飽和単量体を含んでもよい。
The phosphate group-containing unsaturated monomer is represented by the following general formula (3):

(Where R ₇ and R ₁₀ are each independently H or CH ₃ , R ₈ and R ₉ are each independently H, CH ₃ or CH ₂ Cl , and k and p are each independently an integer of 1 to 6) The phosphoric acid group-containing diester unsaturated monomer represented by

  The solid polymer electrolyte membrane of the present invention has high proton conductivity in a wide temperature range and humidity range, and has excellent solvent resistance and water resistance. The solid polymer electrolyte membrane of the present invention comprises (1) a hydrophobic portion comprising a hydrogenated conjugated diene-based liquid oligomer unit and a hydrocarbon skeleton derived from an ethylenically unsaturated bond of a phosphate group-containing unsaturated monomer; (2) Since the phosphoric acid group-containing unsaturated monomer has a hydrophilic part composed of a phosphate group, an ester bond, and an alkylene oxide group, the hydrophilic part composed of a phosphate group and the like has an efficient proton conduction. Presumed to be a route. The solid polymer electrolyte membrane of the present invention is presumed to exhibit excellent solvent resistance and water resistance due to the presence of the hydrophobic portion.

  The solid polymer electrolyte membrane of the present invention having such characteristics includes an electrolyte membrane for a primary battery, an electrolyte membrane for a secondary battery, an electrolyte membrane for a fuel cell, a display element membrane, various sensor membranes, a signal transmission medium membrane, a solid capacitor It can be suitably used for membranes, ion exchange membranes and the like. In particular, when used as an electrolyte membrane of a direct methanol solid polymer fuel cell, it exhibits excellent methanol crossover prevention properties (performance capable of preventing methanol from permeating the solid polymer electrolyte membrane) Guessed.

（ただしR ₅ は水素又はアルキル基であり、R ₆ は水素又は置換もしくは無置換のアルキル基であり、nは１〜６の整数である。）により表すことができる。R ₅ はH又はCH₃であり、R ₆ はH、CH₃又はCH₂Clであるのが好ましい。
[1] Phosphoric acid group-containing unsaturated monomer The phosphoric acid group-containing unsaturated monomer has the following general formula ( 2 ):

Where R ₅ is hydrogen or an alkyl group, R ₆ is hydrogen or a substituted or unsubstituted alkyl group, and n is an integer of 1 to 6. R ₅ is preferably H or CH ₃ and R ₆ is preferably H, CH ₃ or CH ₂ Cl.

Tables 1 and 2 show the structural formulas and physical properties of representative ones of the phosphate group-containing unsaturated monomers represented by the general formula ( 2 ) (phosphate group-containing unsaturated monomers (I)), respectively. Show. These monomers are sold by Unichemical Corporation under the trade name Phosmer (registered trademark). However, the phosphate group-containing unsaturated monomer that can be used in the present invention is not limited to these. The phosphate group-containing unsaturated monomer (I) may be used alone or in combination of two or more thereof.

The phosphoric acid group may be dissociated or may form a complex salt. When forming a complex salt, in order to neutralize the charge, for example, ammonium ions containing mono-, di- or tri-alkyl groups such as primary, secondary, tertiary or quaternary alkyl groups, allyl groups, aralkyl groups, etc. It is preferable to form a complex salt with an alkanolamine residue, particularly N ⁺ R ¹¹ _4-f (OH) _f (wherein R ¹¹ is an alkyl group having 1 to 18 carbon atoms, an aromatic group having 6 to 12 carbon atoms, and carbon. It represents at least one selected from the group consisting of alicyclic groups of formula 6 to 12, and f represents a positive integer of 1 to 3).

（ただしR₇及びR₁₀はそれぞれ独立に水素基又はアルキル基であり、R₈及びR₉はそれぞれ独立に水素基又は置換もしくは無置換のアルキル基であり、k及びpはそれぞれ独立に１〜６の整数である。）により表されるリン酸基含有ジエステル系不飽和単量体（リン酸基含有不飽和単量体(II)）、下記一般式(4):

（ただしR₁₂及びR₁₅はそれぞれ独立に水素基又はアルキル基であり、R₁₃及びR₁₄はそれぞれ独立に水素基又は置換もしくは無置換のアルキル基であり、r及びsはそれぞれ独立に１〜６の整数である。）により表されるピロリン酸基含有不飽和単量体（リン酸基含有不飽和単量体(III)）、及び下記一般式(5):

（ただしR₁₆、R₁₉及びR₂₁はそれぞれ独立に水素基又はアルキル基であり、R₁₇、R₁₈及びR₂₀はそれぞれ独立に水素基又は置換もしくは無置換のアルキル基であり、x、y及びzはそれぞれ独立に１〜６の整数である。）により表されるリン酸基含有不飽和単量体(IV)も使用可能である。 As the phosphate group-containing unsaturated monomer, the following general formula (3):

(However, R ₇ and R ₁₀ are each independently a hydrogen group or an alkyl group, R ₈ and R ₉ are each independently a hydrogen group or a substituted or unsubstituted alkyl group, and k and p are each independently 1 to 1) The phosphoric acid group-containing diester unsaturated monomer (phosphoric acid group-containing unsaturated monomer (II)) represented by the following general formula (4):

(Wherein R ₁₂ and R ₁₅ are each independently a hydrogen group or an alkyl group, R ₁₃ and R ₁₄ are each independently a hydrogen group or a substituted or unsubstituted alkyl group, and r and s are each independently 1 to 1) A pyrophosphate group-containing unsaturated monomer (phosphate group-containing unsaturated monomer (III)) represented by the following general formula (5):

(However, R ₁₆ , R ₁₉ and R ₂₁ are each independently a hydrogen group or an alkyl group, R ₁₇ , R ₁₈ and R ₂₀ are each independently a hydrogen group or a substituted or unsubstituted alkyl group, and x, y And z are each independently an integer of 1 to 6.) It is also possible to use a phosphate group-containing unsaturated monomer (IV) represented by:

  As the phosphate group-containing unsaturated monomer (II), di (methacryloyloxyethyl) phosphate and di (acryloyloxyethyl) phosphate are preferable. As the phosphate group-containing unsaturated monomer (III), di (methacryloyloxyethyl) acid pyrophosphate and di (acryloyloxyethyl) acid pyrophosphate are preferable.

  The phosphoric acid group-containing unsaturated monomer (I) has excellent proton conductivity, and the phosphoric acid group-containing unsaturated monomers (II) to (IV) have a crosslinking action and excellent film forming properties. Therefore, the phosphate group-containing unsaturated monomer (I) and at least one selected from the group consisting of the phosphate group-containing unsaturated monomers (II) to (IV) may be used in combination. Such a combination improves the balance of proton conductivity, solvent resistance and membrane strength of the membrane. Among them, it is preferable to use the phosphate group-containing unsaturated monomers (I) and (II) in combination. When the phosphate group-containing unsaturated monomer (I) and at least one selected from the group consisting of the phosphate group-containing unsaturated monomers (II) to (IV) are used in combination, the formula [phosphate group Containing molar ratio represented by [containing unsaturated monomer (I)] / [total of phosphate group-containing unsaturated monomers (II) to (IV)] is 1 / 0.05 to 1/2. preferable.

  When the phosphate group-containing polymer contains a phosphate group-containing unsaturated monomer component as described above, a high water retention capability can be imparted to the solid polymer electrolyte, and a highly conductive film can be obtained.

（但しR₃及びR₄はそれぞれ独立に(i) エチレン性不飽和結合を１個以上有し、かつ他の原子団を有してもよい炭化水素基、(ii) エチレン性不飽和結合を有さず、かつ他の原子団を有してもよい炭化水素基又は(iii) 水素基であり、かつR₃及びR₄の少なくとも一方は前記(i) エチレン性不飽和結合を有する炭化水素基であり、R ₁ 及びR ₂ はそれぞれ独立に水素基又はメチル基であり、かつR ₁ 及びR ₂ の少なくとも一方は水素基であり、mは重合度を表す。）により表されるものが好ましい。ただし水素化共役ジエン系液状オリゴマーとして、式(1)に示すような重合体鎖中の水素化共役ジエン単位が1,2-結合であるものに限定する趣旨ではなく、水素化共役ジエン単位が1,4-結合であるものであってもよい。
[2] Hydrogenated conjugated diene-based liquid oligomer As the hydrogenated conjugated diene-based liquid oligomer to be copolymerized with the above-mentioned phosphate group-containing unsaturated monomer, each hydrocarbon group having an ethylenically unsaturated bond is at least in the molecule. At least one selected from the group consisting of one hydrogenated butadiene oligomer, one hydrogenated isoprene oligomer, and derivatives thereof is used. The hydrogenated conjugated diene-based liquid oligomer has the following general formula ( 1 ):

(However, R ₃ and R ₄ are each independently (i) a hydrocarbon group which has one or more ethylenically unsaturated bonds and may have other atomic groups, and (ii) an ethylenically unsaturated bond. A hydrocarbon group that does not have and may have another atomic group or (iii) a hydrogen group, and at least one of R ₃ and R ₄ has (i) a hydrocarbon having an ethylenically unsaturated bond R ₁ and R ₂ are each independently a hydrogen group or a methyl group, and at least one of R ₁ and R ₂ is a hydrogen group, and m represents the degree of polymerization). preferable. However, the hydrogenated conjugated diene-based liquid oligomer is not intended to be limited to those in which the hydrogenated conjugated diene unit in the polymer chain as shown in the formula ( 1 ) is a 1,2-bond. It may be a 1,4-bond.

R ₃ and R ₄ are each independently (i) a hydrocarbon group which has one or more ethylenically unsaturated bonds and may have other atomic groups, and (ii) has an ethylenically unsaturated bond. And (iii) a hydrogen group that may have other atomic groups, and at least one of R ₃ and R _{4 is} the hydrocarbon group having (i) an ethylenically unsaturated bond. As long as there is no particular limitation. Examples of other atomic groups that R ₃ and R ₄ may have include at least one selected from the group consisting of urethane bonds, ester bonds, ether bonds, isocyanate groups, hydroxyl groups, carboxyl groups, and alkoxy groups. Specific examples of R ₃ and R ₄ include a (meth) acryl group.

Although there is no restriction | limiting in particular in the molecular weight of a hydrogenated conjugated diene type liquid oligomer, A thing with a number average molecular weight of 500-50,000 is preferable. Examples of commercially available hydrogenated conjugated diene liquid oligomers represented by the formula ( 1 ) include “NISSO-PB TEAI-1000” (manufactured by Nippon Soda Co., Ltd.).

  The hydrogenated conjugated diene-based liquid oligomer may contain other hydrogenated conjugated diene-based monomer units as necessary. For example, when the hydrogenated conjugated diene-based liquid oligomer is a hydrogenated butadiene oligomer or a derivative thereof, a hydrogenated isoprene monomer unit may be included. When the hydrogenated conjugated diene-based liquid oligomer is a hydrogenated isoprene oligomer or a derivative thereof, a hydrogenated butadiene monomer unit may be included. Other hydrogenated conjugated diene monomer units include hydrogenated 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3 -Monomer units such as hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene and chloroprene.

  The hydrogenated conjugated diene-based liquid oligomer may contain an olefin as a copolymerization component. In this case, the hydrogenated conjugated diene-based liquid oligomer may be a random copolymer, a block copolymer, or a graft copolymer.

  By including the hydrogenated conjugated diene-based liquid oligomer as described above, the solid polymer electrolyte membrane has solvent resistance, particularly methanol crossover prevention (when used as an electrolyte membrane of a direct methanol solid polymer fuel cell) , Performance capable of preventing methanol from permeating the solid polymer electrolyte membrane).

[3] Blending ratio The blending ratio of (a) phosphate group-containing unsaturated monomer and (b) hydrogenated conjugated diene-based liquid oligomer in the solid polymer electrolyte membrane is expressed by the formula [((a) phosphate group-containing The mass ratio represented by (unsaturated monomer) / ((b) hydrogenated conjugated diene-based liquid oligomer)] is preferably in the range of 99/1 to 40/60, and is preferably 95/5 to 50/50. A range is more preferable. If this ratio is less than 40/60, the conductivity is insufficient, while if it exceeds 99/1, the solvent resistance and water resistance are insufficient.

[4] Other unsaturated monomers that can be copolymerized The solid polymer electrolyte membrane contains a phosphate group-containing unsaturated monomer and another unsaturated monomer that can be copolymerized with a hydrogenated conjugated diene-based liquid oligomer. It may be obtained by polymerization. Other unsaturated monomers that can be copolymerized can be broadly divided into the following two groups: (1) those containing functional groups and (2) those containing no functional groups.
(1) Unsaturated monomer containing functional group An unsaturated monomer containing a functional group is a compound having at least one functional group and at least one ethylenically unsaturated bond in the molecule. Examples of the functional group include an acidic group and an amino group (including those having an amide group). The acidic group is preferably at least one selected from the group consisting of a sulfonic acid group, a carboxylic acid group and an alcoholic hydroxyl group. Examples of the skeleton having an ethylenically unsaturated bond include a (meth) acrylate skeleton and a (meth) allyl ester skeleton.

（ただしR₂₂は水素基又はメチル基である。）により表される化合物、下記一般式(7)：

（ただしR₂₃は水素基又はメチル基であり、Y₁は置換もしくは無置換の炭素数１〜６のアルキレン基又は炭素数６〜12のアリーレン基である。）により表される化合物、及び下記一般式(8)：

（ただしR₂₄は水素基又はメチル基であり、X₁は−O−基又は−NH−基であり、Y₂は置換もしくは無置換の炭素数１〜６のアルキレン基又は炭素数６〜12のアリーレン基である。）により表される化合物からなる群から選ばれた少なくとも一種が好ましい。 (i) Unsaturated monomer containing sulfonic acid group As an exemplary compound of an unsaturated monomer containing a sulfonic acid group, the following general formula (6):

(Wherein R ₂₂ is a hydrogen group or a methyl group), a compound represented by the following general formula (7):

Wherein R ₂₃ is a hydrogen group or a methyl group, and Y ₁ is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms or an arylene group having 6 to 12 carbon atoms, and General formula (8):

(Wherein R ₂₄ is a hydrogen group or a methyl group, X ₁ is an —O— group or an —NH— group, and Y ₂ is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms or 6 to 12 carbon atoms. And at least one selected from the group consisting of compounds represented by formula (1):

  Examples of the sulfonic acid group-containing unsaturated monomer represented by any one of the general formulas (6) to (8) include allyl sulfonic acid, methallyl sulfonic acid, and vinyl sulfone. Acid, p-styrenesulfonic acid, (meth) acrylic acid butyl-4-sulfonic acid, (meth) acrylooxybenzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (tertiary butylacrylamidesulfonic acid), etc. Can be mentioned. Preferred are vinyl sulfonic acid, p-styrene sulfonic acid and tertiary butyl acrylamide sulfonic acid. However, allyl sulfonic acid and methallyl sulfonic acid have a degradative chain transfer because the allyl group causes a degradative chain transfer. preferable. Specifically, the total of the phosphate group-containing unsaturated monomer and other unsaturated monomers is 100% by mass, and the amount used is at most about 10% by mass.

  The sulfonic acid group may be dissociated or may form a complex salt. When forming a complex salt, it is preferable to form a complex salt with an ammonium ion, an amine residue or an alkali metal as described above for the unsaturated monomer containing a phosphorus acid residue.

(ii) Unsaturated monomer containing a carboxylic acid group Examples of unsaturated monomers containing a carboxylic acid group include (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, maleic acid. An acid anhydride etc. are mentioned. These may be used alone or in combination of two or more.

(iii) Unsaturated monomer containing alcoholic hydroxyl group The unsaturated monomer containing alcoholic hydroxyl group includes glycerol dimethacrylate [for example, “Blemmer GMR”, “Blemmer GMR-R” (Nippon Yushi). Etc.)], glycerol methacrylate acrylate [e.g., trade name "Blemmer GAM", "Blenmer GAM-R" (manufactured by Nippon Oil & Fats Co., Ltd.)], 1,6-hexanediol diglycidyl ether acrylate [e.g. Product name “NK Oligo EA-5521” (manufactured by Shin-Nakamura Chemical Co., Ltd.), etc.], 1,4-butanediol diglycidyl ether acrylate [eg, product name “NK Oligo EA-5520” (Shin Nakamura Chemical Co., Ltd.) Etc.)], bisphenol A type epoxy acrylate [for example, “NK Oligo EA-1020” (manufactured by Shin-Nakamura Chemical Co., Ltd.)], and 2-hydroxy (meta ) Acrylates (for example, 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, etc.). Among them, glycerol dimethacrylate, glycerol methacrylate acrylate, 1,6-hexanediol diglycidyl ether acrylate, 1,4-butanediol diglycidyl ether acrylate and bisphenol A type epoxy acrylate have two ethylenically unsaturated groups in the molecule. It is preferable from the viewpoint.

（ただしR₂₅は水素基又はメチル基であり、R₂₆及びR₂₇はそれぞれ独立に水素基、炭素数１〜４のアルキル基又は炭素数６〜10のアリール基であり、X₂は−O−基又は−NH−基であり、Y₃は置換もしくは無置換の炭素数１〜６のアルキレン基又は置換もしくは無置換の炭素数６〜16のアリーレン基である。）により表される化合物、(b) 下記一般式(10)：

（ただしR₂₈は水素基又はメチル基であり、R₂₉及びR₃₀はそれぞれ独立に水素基、炭素数１〜４のアルキル基又は炭素数６〜10のアリール基である。）により表される化合物、(c) 下記一般式(11)：

（ただしR₃₁は水素基又はメチル基であり、R₃₂及びR₃₃はそれぞれ独立に水素基、炭素数１〜４のアルキル基又は炭素数６〜10のアリール基であり、Y₄は置換もしくは無置換の炭素数１〜６のアルキレン基又は置換もしくは無置換の炭素数６〜16のアリーレン基である。）により表される化合物、(d) 下記一般式(12)：

（ただしR₃₄は水素基又はメチル基であり、R₃₅及びR₃₆はそれぞれ独立に水素基、炭素数１〜４のアルキル基又は炭素数６〜10のアリール基である。）により表される化合物、(e) 下記一般式(13)：

（ただしR₃₇及びR₃₈はそれぞれ独立に水素基又はメチル基であり、R₃₉は水素基、炭素数１〜４のアルキル基又は炭素数６〜10のアリール基であり、Y₅及びY₆はそれぞれ独立に置換もしくは無置換の炭素数１〜６のアルキレン基又は置換もしくは無置換の炭素数６〜16のアリーレン基である。）により表される化合物、及び(f) １個以上のビニル基を有するヘテロ環状アミン化合物からなる群から選ばれた少なくとも一種が挙げられる。 (iv) Amino group-containing unsaturated monomer The amino group-containing unsaturated monomer is not particularly limited as long as it has at least one substituted or unsubstituted amino group and one or more ethylenically unsaturated bonds in the molecule. There is no. As an amino group-containing unsaturated monomer, for example, (a) the following general formula (9):

(However, R ₂₅ is a hydrogen group or a methyl group, R ₂₆ and R ₂₇ are each independently a hydrogen group, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and X ₂ is —O -Group or -NH- group, and Y ₃ is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms or a substituted or unsubstituted arylene group having 6 to 16 carbon atoms.) (b) The following general formula (10):

Wherein R ₂₈ is a hydrogen group or a methyl group, and R ₂₉ and R ₃₀ are each independently a hydrogen group, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Compound (c) The following general formula (11):

(However, R ₃₁ is a hydrogen group or a methyl group, R ₃₂ and R ₃₃ are each independently a hydrogen group, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, and Y ₄ is substituted or An unsubstituted alkylene group having 1 to 6 carbon atoms or a substituted or unsubstituted arylene group having 6 to 16 carbon atoms.) (D) the following general formula (12):

Wherein R ₃₄ is a hydrogen group or a methyl group, and R ₃₅ and R ₃₆ are each independently a hydrogen group, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Compound (e) The following general formula (13):

(However, R ₃₇ and R ₃₈ are each independently a hydrogen group or a methyl group, R ₃₉ is a hydrogen group, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and Y ₅ and Y ₆ And each independently represents a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms or a substituted or unsubstituted arylene group having 6 to 16 carbon atoms, and (f) one or more vinyls And at least one selected from the group consisting of heterocyclic amine compounds having a group.

  Examples of the amino group-containing unsaturated monomer represented by the above formula (9) include N, N-dimethylaminomethyl (meth) acrylate, N, N-diethylaminomethyl (meth) acrylate, and N, N-dipropylamino. Methyl (meth) acrylate, N, N-dibutylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dipropylaminoethyl ( (Meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N-dipropylaminopropyl (meth) Acrylate, N, N-Dibutylaminopropyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, N, N-diethyl Minobutyl (meth) acrylate, N, N-dipropylaminobutyl (meth) acrylate, N, N-dibutylaminobutyl (meth) acrylate, N, N-dimethylaminomethyl (meth) acrylamide, N, N-diethylaminomethyl ( (Meth) acrylamide, N, N-dipropylaminomethyl (meth) acrylamide, N, N-dibutylaminomethyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) Acrylamide, N, N-dipropylaminoethyl (meth) acrylamide, N, N-dibutylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-dipropylaminopropyl (meth) acrylamide, N, N-dibutylamino Lopyl (meth) acrylamide, N, N-dimethylaminobutyl (meth) acrylamide, N, N-diethylaminobutyl (meth) acrylamide, N, N-dipropylaminobutyl (meth) acrylamide, N, N-dibutylaminobutyl ( And (meth) acrylamide.

  Examples of the amino group-containing unsaturated monomer represented by the above formula (10) include vinylamine, N-vinyldimethylamine, N-vinyldiethylamine, N-vinyldiphenylamine and the like.

  Examples of the amino group-containing unsaturated monomer represented by the above formula (11) include allylamine, N, N-dimethyl-p-aminostyrene, N, N-diethyl-p-aminostyrene, dimethyl (p-vinylbenzyl) ) Amine, diethyl (p-vinylbenzyl) amine, dimethyl (p-vinylphenethyl) amine, diethyl (p-vinylphenethyl) amine, dimethyl (p-vinylbenzyloxymethyl) amine, dimethyl [2- (p-vinylbenzyl) Oxy) ethyl] amine, diethyl (p-vinylbenzyloxymethyl) amine, diethyl [2- (p-vinylbenzyloxy) ethyl] amine, dimethyl (p-vinylphenethyloxymethyl) amine, dimethyl [2- (p- Vinylphenethyloxy) ethyl] amine, diethyl (p-vinylphenethyloxymethyl) amine, diethyl [2- (p-vinylphenethyloxy) Ii) ethyl] amine and the like.

  Examples of the amino group-containing unsaturated monomer represented by the above formula (12) include acrylamide, methacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide and the like.

  Examples of the amino group-containing unsaturated monomer represented by the above formula (13) include diallylmethylamine.

  Examples of heterocyclic amine compounds having one or more vinyl groups include 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 1-vinylimidazole, 2-vinylimidazole, 4-vinylimidazole, 5-vinylimidazole, 1-vinylpyrazole, 3-vinylpyrazole, 4-vinylpyrazole, 1-vinyltriazole, 2-vinylpyrimidine, 4-vinylpyrimidine, 5-vinylpyrimidine, 2-vinylpyrazine, 3-vinylpyridazine, 4-vinylpyridazine, 2-vinyltriazine, N-vinylpyrrole, N-vinylindole, N-vinylcarbazole, N-vinylpyrrolidone, N-vinyl-ε-caprolactam, N-vinylsuccinimide, N-vinylglutarimide, N-vinylphthalimide, etc. Can be mentioned.

  Among them, the amino group-containing unsaturated monomer is preferably represented by the above formulas (9), (11) and (13) from the viewpoint of improving the solvent resistance of the solid polymer electrolyte membrane, What is represented by Formula (9) is more preferable.

(2) Unsaturated monomer that does not contain a functional group As the unsaturated monomer that does not contain a functional group, other than those described in (1), at least one ethylenically unsaturated group in the molecule that is not gas at normal temperature. All unsaturated monomers having a saturated bond are targeted, but (meth) acrylonitrile; (meth) acrylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate, alkyl (meth) acrylate; substitution Alternatively, unsubstituted styrenes; vinyls such as vinyl chloride and vinyl acetate are preferably used. Ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, hexamethylenediol di (meth) acrylate, divinylbenzene, and the like containing a plurality of ethylenically unsaturated bonds in one molecule are also resistant to the copolymer. Used for the purpose of improving solvent properties.

  Moreover, the heat resistance and water resistance of a solid polymer electrolyte membrane are improved by including a copolymer component with a fluorine group-containing unsaturated monomer. Fluorine group-containing unsaturated monomers are (i) fluorine group-containing (meth) acrylic acid esters having at least one fluorine group, and (b) fluorine group-containing (meth) acrylic having at least one fluorine group. Acids, (c) a fluorine-containing alkyl group having at least one fluorine group and / or a fluorine-containing olefinically unsaturated monomer having at least one fluorine group and one ethylenically unsaturated bond, And (d) at least one selected from the group consisting of a fluorine group-containing diene unsaturated monomer having a fluorine group-containing alkylene group containing at least one fluorine group and two ethylenically unsaturated bonds. Preferably there is.

（ただしX₃は水素基、フッ素基、少なくとも１個のフッ素基を有するフッ素基含有メチル基又はメチル基であり、R₄₀は少なくとも１個のフッ素基を含有するフッ素基含有アルキル基又はアルキル基である。）により表されるものが好ましい。 As fluorine group-containing (meth) acrylic acid esters, the following general formula (14):

(Where X ₃ is a hydrogen group, a fluorine group, a fluorine group-containing methyl group or a methyl group having at least one fluorine group, and R ₄₀ is a fluorine group-containing alkyl group or alkyl group containing at least one fluorine group) Is preferred.

In the general formula (14), R ₄₀ preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms. When R ₄₀ is a fluorine group-containing alkyl group containing a fluorine group and has 2 or more carbon atoms, it is preferable that all of the hydrogen groups of the terminal methyl group are substituted with fluorine groups. R ₄₀ may be a linear structure or a branched structure. R ₄₀ may have a halogen atom other than fluorine. R ₄₀ may have a hetero atom. Examples of the hetero atom include an etheric oxygen atom and a thioetheric sulfur atom contained between carbon-carbon bonds in R ₄₀ .

  Fluorine group-containing (meth) acrylic esters represented by the general formula (14) include 2,2,2-trifluoroethyl acrylate, 2,2,2-trifluoroethyl methacrylate, tertiary butyl- Examples include α- (trifluoromethyl) acrylate, trifluoroethyl-α- (trifluoromethyl) acrylate, and perfluorooctylethyl (meth) acrylate. Among them, as the fluorine group-containing (meth) acrylic acid esters, 2,2,2-trifluoroethyl methacrylate and tertiary butyl-α- (trifluoromethyl) acrylate are preferable.

（ただしX₄は少なくとも１個のフッ素基を有するフッ素基含有メチル基又はフッ素基である。）により表されるものが好ましい。上記一般式(15)においてX₄はパーフルオロメチル基又はフッ素基であるのがより好ましい。フッ素基含有（メタ）アクリル酸類としては、α-（トリフルオロメチル）アクリル酸が特に好ましい。 As fluorine-containing (meth) acrylic acids, the following general formula (15):

(Wherein X ₄ is a fluorine group-containing methyl group or fluorine group having at least one fluorine group) is preferred. In the general formula (15), X ₄ is more preferably a perfluoromethyl group or a fluorine group. As the fluorine group-containing (meth) acrylic acid, α- (trifluoromethyl) acrylic acid is particularly preferable.

（ただしRf₁は少なくとも１個のフッ素基を含有するフッ素基含有アルキル基であり、X₅、X₆及びX₇はそれぞれ独立に水素基又はフッ素基である。）又は下記一般式(17)：

（ただしX₈、X₉及びX₁₀はそれぞれ独立に少なくとも１個のフッ素基を有するフッ素基含有メチル基又はフッ素基であり、X₁₁はフッ素基、その他のハロゲン、少なくとも１個のフッ素基を有するフッ素基含有メチル基、アルコキシ基、フッ素基含有アルコキシ基、アルキル基又は水素基である。）により表されるものが好ましい。 The fluorine group-containing olefinically unsaturated monomer is represented by the following general formula (16):

(Wherein Rf ₁ is a fluorine group-containing alkyl group containing at least one fluorine group, and X ₅ , X ₆ and X ₇ are each independently a hydrogen group or a fluorine group) or the following general formula (17) :

(However, X ₈ , X ₉ and X ₁₀ are each independently a fluorine-containing methyl group or fluorine group having at least one fluorine group, and X ₁₁ is a fluorine group, other halogens, or at least one fluorine group. Preferably a fluorine group-containing methyl group, an alkoxy group, a fluorine group-containing alkoxy group, an alkyl group or a hydrogen group.

The fluorine group-containing alkyl group Rf ₁ containing a fluorine group in the general formula (16) is preferably a perfluoroalkyl group. Rf ₁ preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms. Rf ₁ may be a linear structure or a branched structure, but is preferably a linear structure. Rf ₁ may have a halogen atom other than fluorine. Rf ₁ may have a hetero atom. Examples of the hetero atom include an etheric oxygen atom and a thioetheric sulfur atom contained between carbon-carbon bonds in Rf ₁ .

（但しRf₁は上記式(16)と同じである。）により表されるものがより好ましい。 Examples of the fluorine-containing olefinically unsaturated monomer represented by the general formula (16) include the following general formula (18):

(Wherein Rf ₁ is the same as that in the above formula (16)) is more preferable.

  Examples of the fluorine group-containing olefinically unsaturated monomer represented by the general formula (18) include (perfluorobutyl) ethylene, (perfluorohexyl) ethylene, (perfluorooctyl) ethylene, and (perfluorodecyl) ethylene. Etc. Of these, (perfluorobutyl) ethylene, (perfluorohexyl) ethylene and (perfluorooctyl) ethylene are preferable as the fluorine group-containing olefinic unsaturated monomer.

X ₈ , X ₉ and X _{10 in the} general formula (17) are preferably a perfluoromethyl group or a fluorine group. When X ₁₁ in the general formula (17) is an alkyl group, an alkoxy group, or a fluorine group-containing alkoxy group, the carbon number thereof is preferably 1 to 10. Examples of the fluorine group-containing olefinically unsaturated monomer represented by the general formula (17) include hexafluoropropene, chlorotrifluoroethylene, 1-methoxy- (perfluoro-2-methyl-1-propene) and the like. Can be mentioned.

（ただしRf₂は少なくとも１個のフッ素基を含有するフッ素基含有アルキレン基であり、X₁₂、X₁₃、X₁₄、X₁₅、X₁₆及びX₁₇はそれぞれ独立に水素基又はフッ素基である。）により表されるものが好ましい。 As the fluorine group-containing diene unsaturated monomer, the following general formula (19):

(However, Rf ₂ is a fluorine-containing alkylene group containing at least one fluorine group, and X ₁₂ , X ₁₃ , X ₁₄ , X ₁₅ , X ₁₆ and X ₁₇ are each independently a hydrogen group or a fluorine group. .) Are preferred.

The fluorine group-containing alkylene group Rf ₂ containing at least one fluorine group in the general formula (19) is preferably a perfluoroalkylene group. Rf ₂ preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms. Rf ₂ may be a linear structure or a branched structure, but is preferably a linear structure. Rf ₂ may have a halogen atom other than fluorine. Rf ₂ may have a hetero atom and / or a hetero atom group. The hetero atom, carbon in Rf ₂ - etheric oxygen atoms contained in the carbon-carbon bond, and the like thioether sulfur atom. Examples of the hetero atom group include an ester bond.

（但しRf₂は上記式(19)と同じである。）により表されるものが、より好ましい。 Examples of the fluorine-containing olefinically unsaturated monomer represented by the general formula (19) include the following general formula (20):

(Wherein Rf ₂ is the same as that in the above formula (19)) is more preferable.

  Examples of the fluorine-containing diene unsaturated monomer represented by the general formula (20) include 1,4-divinyl (perfluorobutylene) (also known as 1,4-divinyloctafluorobutane), 1,6- Divinyl (perfluorohexylene) (alias: 1,6-divinyldodecafluorohexane) and 1,8-divinyl (perfluorooctylene) (alias: 1,8-divinylhexadecafluorooctane) are preferred.

  Each of the above four types of fluorine group-containing unsaturated monomers may be used alone or in combination of two or more. When using 2 or more types together, for example, fluorine group-containing olefinic unsaturated monomer and / or fluorine group-containing diene unsaturated monomer, fluorine group-containing (meth) acrylic acid esters and / or fluorine group-containing The composition etc. which mixed (meth) acrylic acid can be mentioned.

[5] Use ratio of each unsaturated monomer Mass ratio of phosphate group-containing unsaturated monomer [1] to other unsaturated monomer [4] in any of the solid polymer electrolyte membranes [1] / [4] is preferably in the range of 100/0 to 20/80, and more preferably [1] / [4] = 90/10 to 40/60. In addition, among other unsaturated monomers [4], the mass ratio of the unsaturated monomer (1) containing a functional group and the other unsaturated monomer (2) is positive for proton conductivity. The unsaturated monomer (1) / unsaturated monomer (2) should be in the range of 100/0 to 50/50 so that the unsaturated monomer (1) that provides the effect is dominant. preferable. Therefore, in particular, when a sulfonic acid group-containing unsaturated monomer is used as the unsaturated monomer (1) containing an acid group, the phosphoric acid group-containing unsaturated monomer / sulfonic acid group-containing unsaturated monomer Is a mass ratio of 100/0 to 20/80, preferably 80/20 to 40/60, and the mass ratio of sulfonic acid group-containing unsaturated monomer / other acid group-containing unsaturated monomer is 100 / 0-50 / 50.

[6] Other polymers that can be mixed In order to further improve the film-forming properties when producing solid polymer electrolyte membranes, and the strength, durability, solvent resistance, water resistance, etc. of solid polymer electrolyte membranes, Other polymers that are compatible with the (co) polymer constituting the polymer electrolyte membrane can be mixed. Examples of other polymers include polyamide resin, polyvinyl alcohol, polyacrylamide, polyacrylic acid, melamine resin, cellulose, and modified products thereof. As the polyamide resin, N-alkoxyalkylated polyamide described in Patent Document 1 is preferable.

[7] Method for Producing Solid Polymer Electrolyte Membrane The solid polymer electrolyte membrane of the present invention comprises (a) copolymerizing the phosphate group-containing unsaturated monomer and the hydrogenated conjugated diene-based liquid oligomer by solution polymerization. (B) containing the phosphate group-containing unsaturated monomer, the hydrogenated conjugated diene-based liquid oligomer, the photosensitizer, and the solvent. It can be produced by casting and photopolymerizing the composition. Hereinafter, a method of preparing a solid polymer electrolyte by solution polymerization and then forming a film by a casting method will be described in detail.

(1) Preparation of solid polymer electrolyte (a) Dropping method First, a solution composed of (hydrogenated conjugated diene liquid oligomer + solvent) (hydrogenated conjugated diene liquid oligomer-containing solution) is mixed with a phosphate group-containing unsaturated monomer. A method of radical polymerization by dropping a solution (a phosphate group-containing unsaturated monomer-containing solution: solution (A)) consisting of a monomer + a polymerization initiator + a solvent (+ other unsaturated monomer)] To do. As the solvent, a common solvent in which the phosphate group-containing unsaturated monomer, the hydrogenated conjugated diene liquid oligomer, and the copolymer to be generated are all dissolved is used. Such solvents include N, N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), hexamethylphosphoramide (HMPA), toluene, methyl ethyl ketone (MEK) Methyl isobutyl ketone (MIBK), diisopropyl ether (DIPE), dioxane, N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and the like.

  As polymerization initiators, 2, 2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate), Examples thereof include azo initiators such as dimethyl 2, 2′-azobisisobutyrate, and peroxide initiators such as lauryl peroxide, benzoyl peroxide, and tert-butyl peroxy pivalate.

  The polymerization procedure is described. First, a hydrogenated conjugated diene-based liquid oligomer-containing solution is placed in a stirrer, an adder, and a reactor equipped with a reflux condenser, and a phosphate group-containing unsaturated monomer-containing solution (solution (A)) is placed in an adder. The concentration of the unsaturated monomer component in the solution (A) is preferably 5 to 70% by mass. The temperature inside the reactor is raised to a temperature of 40 ° C. to 100 ° C., preferably 50 ° C. to 90 ° C., while nitrogen is passed through the gas phase in the reactor. Immediately after reaching the predetermined temperature, the solution (A) in the adder is dropped over a predetermined time. The dropping time is preferably 15 to 120 minutes.

  The whole amount of the solution (A) is added to the hydrogenated conjugated diene-based liquid oligomer-containing solution, followed by aging for 1 to 10 hours. After the entire amount of the solution (A) is added to the hydrogenated conjugated diene-based liquid oligomer-containing solution, the polymerization initiator may be added again as necessary. The aging temperature does not need to be constant from the beginning to the end, and a method of increasing the temperature at the end of aging and reducing the unreacted monomer as much as possible may be adopted.

  The polymerization solution preferably has an initial concentration of (unsaturated monomer component + hydrogenated conjugated diene-based liquid oligomer component) of 3 to 60% by mass, and more preferably 5 to 30% by mass. If the initial concentration of (unsaturated monomer component + hydrogenated conjugated diene-based liquid oligomer component) in the polymerization solution is not within the above preferred range, the copolymer will gel and become insoluble in various solvents. . The total amount of the polymerization initiator used is 0.005 to 0.5% by mass based on 100% by mass of the unsaturated monomer component [phosphate group-containing unsaturated monomer (+ other unsaturated monomer)]. Preferably, it is 0.01-0.3 mass%.

(B) Batch addition method The batch addition method may be essentially the same as the dropping method except that the solution (A) is added to a solution consisting of (hydrogenated conjugated diene-based liquid oligomer + solvent). . However, when adding the phosphate group-containing unsaturated monomer (+ other unsaturated monomer) all at once, it is not always necessary to use a solvent.

  The solid polymer electrolyte obtained by either the dropping method or the batch addition method is not particularly limited in its copolymer structure, and may be, for example, a block copolymer or a graft copolymer. However, a block copolymer is preferable from the viewpoint of improving proton conductivity, solvent resistance and water resistance of the solid polymer electrolyte membrane.

(2) Casting film formation method The solid polymer electrolyte prepared by solution polymerization is formed into a film by the casting method. In the casting method, a solid polymer electrolyte solution is cast on a horizontal glass plate or tray, and the solvent used in the polymerization reaction is evaporated. The solvent is evaporated by heating or depressurizing the cast mixed solution. Specifically, it is preferable to heat-dry at about 90 to 150 ° C. for about 1 to 30 minutes. The pressure during the heat drying treatment is preferably normal pressure to 10 mmHg (absolute pressure).

  Since the film obtained by evaporating the solvent by heating and / or decompression also contains impurities such as residual solvent, unreacted components such as monomers, it is preferable to extract the impurities. Extraction is performed by immersing the membrane in a poor solvent and then removing it. As the poor solvent, water, methanol and the like are preferable. Alternatively, extraction may be performed by repeating a combination operation consisting of immersion in about 0.5 to 1N hydrochloric acid and immersion in water a plurality of times. When water or methanol is used as the poor solvent, each may be used alone or in combination. The amount of the poor solvent used for one extraction operation is 10 to 100 times the volume of the membrane. The immersion temperature is usually room temperature, and if necessary, the film may be heated to such an extent that the film does not deteriorate. With respect to the immersion time, for example, when extraction is performed at room temperature using water or methanol as a poor solvent, the impurities can be almost extracted by one extraction operation if immersed for about 24 hours. You may repeat extraction by a poor solvent as needed. For example, there is a method in which a combination operation consisting of immersion in about 1N hydrochloric acid at room temperature and immersion in water is repeated a plurality of times, and further immersed in methanol at room temperature for about 24 hours. When repeating extraction with a poor solvent, a heating and vacuum drying operation may be performed between the extraction operations.

  It is preferable to further heat the formed film (coating), whereby condensation occurs between phosphoric acid groups incorporated in the copolymer, and mechanical strength and solvent resistance are improved. Specifically, it is preferable to heat and dry at 90 to 150 ° C. for about 1 to 30 minutes. The pressure during the heat drying treatment is preferably normal pressure to 10 mmHg (absolute pressure).

[8] Characteristics of the solid polymer electrolyte membrane The solid polymer electrolyte membrane of the present invention has a conductivity of 10 ⁻⁴ to 10 ⁻² S · cm ⁻¹ under a relative humidity of 90% and a temperature of 30 to 90 ° C. Excellent proton conductivity, and the temperature dependence of the proton conductivity is small. Here, the conductivity is obtained from a resistance value obtained by performing plane complex impedance analysis on data measured by the complex impedance method and further performing cole-cole plot graphic processing. The solid polymer electrolyte membrane of the present invention comprises (1) a hydrophobic portion comprising a hydrogenated conjugated diene-based liquid oligomer unit and a hydrocarbon skeleton derived from an ethylenically unsaturated bond of a phosphate group-containing unsaturated monomer; (2) Since it has a structure having a phosphate group derived from a phosphate group-containing unsaturated monomer, a hydrophilic part consisting of a chain of an ester bond and an alkylene oxide group, the hydrophilic part consisting of a phosphate group or the like is efficient. It is presumed to be a proton conduction path.

  The solid polymer electrolyte membrane of the present invention has both methanol extraction rate and water extraction rate of 10% by mass or less, and is excellent in methanol resistance and water resistance. Here, the methanol extraction rate is the mass loss measured after immersing the membrane in a large excess of methanol at room temperature for 24 hours and drying at 105 ° C. for 1 hour, and the water extraction rate is the water extraction rate. Was measured for the decrease in mass after being immersed for 24 hours at room temperature and dried at 105 ° C. for 1 hour. The solid polymer electrolyte membrane of the present invention having such characteristics is expected to have excellent methanol crossover prevention properties when used in a direct methanol solid polymer fuel cell.

  The thickness of the solid polymer electrolyte membrane is usually 30 to 200 μm, preferably 30 to 100 μm.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Examples 1-7
A phosphate group-containing unsaturated monomer (Phosmer M) -containing solution containing acrylonitrile having the composition shown in Table 3 and a hydrogenated conjugated diene-based liquid oligomer (NISSO-PB TEAI-1000) -containing solution having the composition shown in Table 4 Each was prepared, and a copolymer was prepared according to the blending mass ratio shown in Table 5. A hydrogenated conjugated diene-based liquid oligomer-containing solution having the composition shown in Table 4 is placed in a reactor connected to a reflux condenser, a dropping funnel, a thermometer, and a nitrogen gas inlet tube, and stirred while introducing nitrogen gas into the gas phase portion. The temperature was raised to a polymerization temperature of 80 ° C. After confirming that the internal temperature reached 80 ° C., in Examples 1 to 4, the phosphate group-containing unsaturated monomer-containing solution placed in the dropping funnel was dropped, and in Examples 5 to 7, phosphate group-containing Saturated monomer-containing solution and 2, 2 '-Azobisisobutyronitrile (AIBN) was added all at once. Thereafter, the solution was aged for 3 hours to obtain a solution containing each copolymer. After cooling, each solution was cast onto a Teflon (registered trademark) sheet, dried under the conditions shown in Table 5, and impurities were extracted to produce a solid polymer electrolyte membrane.

Notes: (1) 0.2% by mass of 2,2 with 100% by mass of methacryloyloxyethyl phosphate (Phosmer M) '-Including azobisisobutyronitrile.
(2) Methacryloyloxyethyl phosphate (molecular weight: 210).
(3) Acrylonitrile (molecular weight: 53).
(4) A composition containing methacryloyloxyethyl phosphate (molecular weight: 210) and di (methacryloyloxyethyl) phosphate (molecular weight: 322) at a theoretical molar ratio of about 1: 1, manufactured by Unichemical Co., Ltd.
(5) A composition comprising acryloyloxyethyl phosphate (molecular weight: 196) and di (acryloyloxyethyl) phosphate (molecular weight: 294) in a theoretical molar ratio of about 1: 1, manufactured by Unichemical Co., Ltd.
(6) N, N-dimethylacetamide.
(7) N-methyl-2-pyrrolidone.
(8) Tetrahydrofuran.

Note: (1) Product name “NISSO-PB TEAI-1000”, manufactured by Nippon Soda Co., Ltd.
(2) N, N-dimethylacetamide.
(3) N-methyl-2-pyrrolidone.
(4) Tetrahydrofuran.

表５（続き）

表５（続き）

Table 5 (continued)

Table 5 (continued)

Notes: (1) Methacryloyloxyethyl phosphate (molecular weight: 210).
(2) Product name “NISSO-PB TEAI-1000”, manufactured by Nippon Soda Co., Ltd.
(3) Acrylonitrile (molecular weight: 53).
(4) The phosphate group-containing unsaturated monomer-containing solution is dropped into the conjugated diene-based liquid oligomer-containing solution.
(5) Batch addition of phosphate group-containing unsaturated monomer-containing solution to conjugated diene-based liquid oligomer-containing solution.
(6) N, N-dimethylacetamide.
(7) 2, 2 '-Azobisisobutyronitrile.
(8) Phosmer M is 100 mass%.
(9) Measure the mass loss after immersing the membrane in a large excess of methanol at room temperature for 24 hours and drying at 105 ° C for 1 hour.
(10) The extraction operation of immersing in 1N hydrochloric acid for 20 minutes and then in water for 20 minutes was repeated three times.
(11) It was immersed in methanol at room temperature for 24 hours.

Example 8
A phosphate group-containing unsaturated monomer-containing solution containing Phosmer 2M having the composition shown in Table 3 and a hydrogenated conjugated diene-based liquid oligomer (NISSO-PB TEAI-1000) -containing solution having the composition shown in Table 4 were prepared. A solid polymer electrolyte membrane was produced in the same manner as in Example 5 except that the blending mass ratio shown in Table 5 was followed.

Example 9
A phosphate group-containing unsaturated monomer-containing solution containing Phosmer 2A having a composition shown in Table 3 and a hydrogenated conjugated diene-based liquid oligomer (NISSO-PB TEAI-1000) -containing solution having a composition shown in Table 4 were prepared, A solid polymer electrolyte membrane was produced in the same manner as in Example 5 except that the blending mass ratio shown in Table 5 was followed.

Notes: (1) Methacryloyloxyethyl phosphate (molecular weight: 210).
(2) A composition containing methacryloyloxyethyl phosphate (molecular weight: 210) and di (methacryloyloxyethyl) phosphate (molecular weight: 322) at a theoretical molar ratio of about 1: 1, manufactured by Unichemical Co., Ltd.
(3) A composition comprising acryloyloxyethyl phosphate (molecular weight: 196) and di (acryloyloxyethyl) phosphate (molecular weight: 294) at a theoretical molar ratio of about 1: 1, manufactured by Unichemical Co., Ltd.
(4) Product name “NISSO-PB TEAI-1000”, manufactured by Nippon Soda Co., Ltd.
(5) Acrylonitrile (molecular weight: 53).
(6) The phosphate group-containing unsaturated monomer-containing solution is dropped into the conjugated diene-based liquid oligomer-containing solution.
(7) N-methyl-2-pyrrolidone.
(8) Tetrahydrofuran.
(9) Volume ratio
(10) 2, 2 '-Azobisisobutyronitrile.
(11) Phosmer M is 100 mass%.
(12) Measure the mass loss after immersing the membrane in a large excess of methanol at room temperature for 24 hours and drying at 105 ° C for 1 hour.
(13) It was immersed in methanol at room temperature for 24 hours.

<Methanol extraction test>
The solid polymer electrolyte membranes of Examples 1, 2, 5, and 6 were immersed in a large excess of methanol at room temperature for 24 hours, and the mass loss after drying at 105 ° C. for 1 hour was measured. From Tables 5 and 6, an excellent methanol extraction rate of 10% by mass or less was shown in any membrane.

<Evaluation of proton conductivity>
Proton conductivity was measured using the complex impedance method. A 3 cm × 1 cm rectangular sample cut out from the membranes of Examples 1 to 9 produced by the method described above was placed in an open impedance cell. This cell is installed in a constant temperature and humidity chamber, relative humidity: 90%, measurement temperature range: impedance measurement at 30-90 ° C, and relative humidity range: 50-90%, measurement temperature: impedance measurement at 80 ° C (Examples 4 and 7 to 9) were performed. The obtained data was subjected to plane complex impedance analysis, and the conductivity was obtained from the resistance value of the sample obtained by performing the cole-cole plot graphic processing on the result. The results are shown in FIGS.

From the results shown in FIGS. 1 to 3, the conductivity of the solid polymer electrolyte membrane of the present invention is 10 ⁻³ to 10 ⁻² S · cm ⁻¹ at 90% relative humidity and 30 to 90 ° C. It can be seen that the polymer electrolyte is in the order and has a good level as a polymer electrolyte having a phosphate group as a functional group, and the temperature dependence of conductivity is small. From the results shown in FIGS. 4 and 5, the conductivity of the solid polymer electrolyte membrane of the present invention is 10 ⁻⁵ to 10 ⁻³ S · cm ^{−1 at} a temperature of 80 ° C. and a relative humidity range of 50 to 90%. Therefore, it was a good level as a polymer electrolyte having a phosphate group as a functional group.

It is a graph which shows the relationship between temperature T (degreeC) and electrical conductivity log ((sigma) / S * cm < ^-1 >) by a cole-cole plot about the solid polymer electrolyte membrane of Examples 1-4. It is a graph which shows the relationship between temperature T (degreeC) and electrical conductivity log ((sigma) / S * cm < ^-1 >) by a cole-cole plot about the solid polymer electrolyte membrane of Examples 5-7. It is a graph which shows the relationship between temperature T (degreeC) and electrical conductivity log ((sigma) / S * cm < ^-1 >) by the cole-cole plot about the solid polymer electrolyte membrane of Example 8, 9. FIG. It is a graph which shows the relationship between relative humidity (%) and electrical conductivity log ((sigma) / S * cm < ^-1 >) by a cole-cole plot about the solid polymer electrolyte membrane of Example 4, 7. FIG. It is a graph which shows the relationship between relative humidity (%) and electrical conductivity log ((sigma) / S * cm < ^-1 >) by a cole-cole plot about the solid polymer electrolyte membrane of Example 8, 9. FIG.

Claims (6)

At least (a) a phosphate group-containing unsaturated monomer having at least one phosphate group and one or more ethylenically unsaturated bonds in the molecule;
(b) Formula (1a):

A polymer chain comprising a repeating unit represented by the formula ( wherein R ₁ and R ₂ are each independently a hydrogen group or a methyl group, and at least one of R ₁ and R ₂ is a hydrogen group): 1b):

And a structural unit bonded to one end of the polymer chain (where R ₁ and R ₂ are the same as in formula (1a), and R ₃ has (i) one or more ethylenically unsaturated bonds) And (ii) a hydrocarbon group that does not have an ethylenically unsaturated bond and may have another atomic group, or (iii) a hydrogen group And formula (1c):

And a structural unit bonded to the other end of the polymer chain (where R ₁ and R ₂ are the same as in formula (1a), and R ₄ has (i) one or more ethylenically unsaturated bonds) And (ii) a hydrocarbon group that does not have an ethylenically unsaturated bond and may have another atomic group, or (iii) a hydrogen group And at least one of R ₃ and R ₄ is (i) a hydrocarbon group having an ethylenically unsaturated bond, and a number average molecular weight of 500 to 50,000 is a hydrogenated conjugated diene-based liquid oligomer A solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell , characterized in that The solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell according to claim 1, wherein (a) a phosphate group-containing unsaturated monomer and (b) a hydrogenated conjugated diene-based liquid oligomer are combined. The ratio is such that the mass ratio represented by the formula [((a) phosphate group-containing unsaturated monomer) / ((b) hydrogenated conjugated diene-based liquid oligomer)] is 99/1 to 40/60. A solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell , characterized by being in a range. The solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell according to claim 1 or 2, wherein the phosphate group-containing unsaturated monomer has the following general formula ( 2 ):

(Wherein R ₅ is H or CH _3, R ₆ is H, CH ₃ or CH ₂ Cl, n is an integer of 1-6.) Directly, characterized in that it comprises a compound represented by -Type solid polymer electrolyte membrane for solid polymer electrolyte fuel cells . The solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell according to any one of claims 1 to 3 , wherein the (a) phosphate group-containing unsaturated monomer and the (b) hydrogenated conjugate A copolymer of a diene-based liquid oligomer and (c) an unsaturated monomer other than (a) and (b),
(C) is at least one functional group selected from the group consisting of (c-1) (i) an ethylenically unsaturated bond and (ii) a sulfonic acid group, a carboxylic acid group, an alcoholic hydroxyl group and an amino group. An unsaturated monomer each having one or more thereof in the molecule, and
(c-2) It has one or more ethylenically unsaturated bonds in the molecule, but has no sulfonic acid group, carboxylic acid group, alcoholic hydroxyl group or amino group, and (meth) acrylonitrile, (meta ) Acrylic esters, substituted or unsubstituted styrenes, vinyl chloride, vinyl acetate and fluorine-containing unsaturated monomers having one or more fluorine groups and one or more ethylenically unsaturated bonds in the molecule At least one unsaturated monomer selected from the group consisting of
A solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell , characterized by being either or both of the above . 5. The solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell according to claim 4, wherein the mass ratio of (a) to (c) is 20/80 or more, and (c-1) The solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell, wherein the mass ratio of (c-2) to (c-2) is (100/0) to (50/50). The solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell according to any one of claims 1 to 5 , wherein the phosphate group-containing unsaturated monomer is represented by the following general formula (3):

(Where R ₇ and R ₁₀ are each independently H or CH ₃ , R ₈ and R ₉ are each independently H, CH ₃ or CH ₂ Cl , and k and p are each independently an integer of 1 to 6) A solid polymer electrolyte membrane for a direct methanol solid polymer fuel cell , comprising a phosphate ester-containing diester unsaturated monomer represented by:

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