JP4438953B2 - Proton conductive film forming composition, proton conductive film forming method, and proton conductive film - Google Patents

Description

The present invention relates to a proton conductive film formed using a high ionic conductivity of the membrane proton conductive film forming composition capable of forming a and proton conductive film forming method and the composition of the.

  In recent years, application development of polymer electrolyte fuel cells (hereinafter referred to as fuel cells) has been promoted in various fields. This is because the power generation principle of the fuel cell is different from the power generation principle of the conventional internal combustion engine generator, and the chemical energy of the fuel can be directly converted into electric energy by electrochemically oxidizing the fuel. This is because it has characteristics of high efficiency, small size, quietness and cleanness.

  Various compounds have been proposed as polymer electrolytes, which are the core parts, and typical ones are perfluorosulfonic acid polymers known by trade names such as “Nafion (DuPont: product name)”. It is. This polymer has a chemical structure in which a side chain having a sulfonic acid group at an end is bonded to a main chain having a tetrafluoroethylene skeleton through an ether bond. Since it has a hydrophobic tetrafluoroethylene chain part and a hydrophilic sulfonic acid group side chain part in the molecule, it is microphase-separated into a hydrophobic part and a hydrophilic part to hydrate the hydrophilic part Proton ion conduction is carried out via the sulfonic acid group.

  When such a perfluorosulfonic acid polymer is used as an electrolyte, the ionic conductivity of the polymer depends on the water content, and the water content of the electrolyte needs to be kept high in order to obtain high ionic conductivity. For this reason, it is necessary to provide a humidification mechanism in the fuel cell, and the reaction temperature is generally limited to a range of 60 to 90 ° C.

  Since current fuel cells may block gas flow paths due to the aggregation of moisture added to fuel gas and oxygen gas by the humidification mechanism and moisture generated by the power generation reaction during power generation operation, There is a deteriorating problem. For this reason, it is important to control the mechanism and operating conditions to keep the moisture of the electrolyte moderate, and appropriate moisture management according to the structure and operating conditions of the electrode stack is required. As described above, the current perfluorosulfonic acid polymer has excellent characteristics as an electrolyte of a fuel cell, but has a problem that management during operation is required.

  In order to solve this problem, an electrolyte exhibiting high ionic conductivity even under non-humidified conditions has been developed. For example, a method of moisturizing a perfluorosulfonic acid polymer with a moisturizer such as molecular sieves, silica gel, polyethylene oxide, a low molecular weight sulfonic acid group-containing compound, a basic polymer with a phosphoric acid compound, etc. Method using electrolyte, method using electrolyte mixed with conductive material such as tin dioxide hydrate, zinc dioxide hydrate, tungsten trioxide hydrate, polymer, method using inorganic electrolyte such as phosphosilicate gel Etc. have been proposed.

  Among these, the phosphosilicate gel electrolyte is an inorganic conductive material using phosphoric acid and silicon, phosphoric acid is responsible for conductivity, silicon is responsible for strength, and is relatively high even under dry conditions. It has the feature of obtaining ionic conductivity, and has attracted attention as an electrolyte that can be used under non-humidified conditions. However, there is a problem that cracks are liable to occur due to poor flexibility and moisture permeability. Furthermore, in order to ensure sufficient conductivity, when the phosphoric acid component is increased, the mechanical strength is insufficient, the phosphoric acid component is likely to bleed out, and there is a problem that the electrical conductivity decreases with time.

  On the other hand, in general, polyimide resin has high heat resistance and excellent electrical insulation, so that it is used as a surface protection film and interlayer insulation film for electrical parts and semiconductor materials as a material for printed circuit boards, heat-resistant adhesive tapes, and resin varnishes. Is also used. Attempts to obtain a solid electrolyte by combining a phosphoric acid compound with this have been made (see Patent Document 1: Japanese Patent Application Laid-Open No. 2004-95255).

  However, the polyimide resin is soluble only in a limited solvent, has poor moisture permeability, and the mixed phosphate compound is not compatible with the polyimide resin at all, so that it separates over time, and the proton conductivity has good reproducibility. Therefore, it is difficult to form a film for supporting the electrolyte, and its application as an electrolyte has been limited.

JP 2004-95255 A

The present invention has been made in view of the above circumstances, excellent in stability and mechanical strength, low humidity giving a high ionic conductivity even at a solid proton conductor capable to form a useful conductive film as an electrolyte sex film forming composition, and to provide a forming method and a proton-conducting self-supporting film of the proton conductive membrane.

As a result of intensive studies to achieve the above object, the present inventors have determined that a proton conductive film comprising a polyimide silicone resin, a polymerizable acidic phosphate containing a methacryloxy group or an acryloxy group, and a radical generator. While the forming composition maintains ionic conductivity and high strength, the increase in resistance value is small even under non-humidified conditions, workability, flexibility and moisture permeability are imparted, handling is good, and conductivity Was found to be fully expressed.

  That is, the present invention increases the compatibility of the polyimide resin with the phosphoric acid compound, improves the solubility in the solvent, improves the adhesion to the substrate, imparts flexibility and moisture permeability, and at the same time provides ionic conductivity. For the purpose of stable expression, a siloxane chain is introduced into the polyimide skeleton. Furthermore, it has been found that by using a polyacid in combination, the increase in resistance value is reduced even under non-humidified conditions while maintaining ionic conductivity and high strength, and the conductivity is sufficiently developed. As a result, it has been found that the film strength and conductivity are both improved and the workability of the film formation is good under any environmental atmosphere. According to the above, cracks are not generated even in a long-term high-temperature and high-humidity environment, and a highly ionic conductive film with moisture permeability is formed, which is high even in a low-humidity environment. A film that can maintain conductivity can be formed.

Accordingly, the present invention provides (i) a polyimide silicone resin having a polystyrene-converted weight average molecular weight of 5,000 to 100,000 by GPC having a repeating unit represented by the following general formula (1), and (ii) a methacryloxy group or Provided is a composition for forming a proton conductive film comprising a polymerizable acidic phosphate ester containing an acryloxy group and (iii) a radical generator.

（式中、Ｘは四価の有機基、Ｙは二価の有機基、Ｚはオルガノポリシロキサン基を有する二価の有機基であり、ｐ及びｑはそれぞれこのポリイミドシリコーン樹脂の重量平均分子量を上記値とする正の整数で、ｑ／（ｐ＋ｑ）＝０．１〜０．９５である。）
この場合、（ｉｉ）成分の重合性酸性リン酸エステルの含有量が、（ｉ）成分と（ｉｉ）成分の合計の量に対し、５〜７５質量％の範囲にあることが好ましい。

(Wherein, X is a tetravalent organic group, Y is a divalent organic radical, Z is a divalent organic group having an organopolysiloxane group, a weight average molecular weight of p and q is the polyimide silicone resin respectively (It is a positive integer having the above value, and q / (p + q) = 0.1 to 0.95 .)
In this case, the content of the polymerizable acidic phosphate of component (ii) is preferably in the range of 5 to 75% by mass with respect to the total amount of component (i) and component (ii).

  Moreover, it is preferable that this composition for electroconductive film formation contains a polyacid further, and the content is 5-50 mass% with respect to the total amount of (i) and (ii) component. In addition, it is preferable that Z of the polyimide silicone resin (i) is a divalent group having an organopolysiloxane group having a vinyl group in the side chain.

In the present invention, the film formed by applying the composition for forming a conductive film on a base material is further heated at a temperature of 60 ° C. or higher and 220 ° C. or lower, or an ultraviolet ray or electron beam having a shorter wavelength than visible light. A method of forming a proton conductive film characterized by irradiating electromagnetic waves such as X-rays, γ-rays or the like, or using these together to crosslink and insolubilize, and the conductive material on a substrate coated with a fluorine-based film. Provided is a proton conductive self-supporting film formed by coating a film formed by applying a composition for forming a conductive film, cross-linking and insolubilizing the film, and peeling the film from a fluorine-based film.

The polyimide silicone resin that is the main component of the present invention is a highly heat-resistant material, and has the effect of imparting flexibility and moisture permeability to the material by adding a silicone component. Since the responsible acidic acidic phosphate ester can be mixed at the monomer stage, a homogeneous composition can be obtained. According to the present invention, an ion conductive film can be easily formed from the composition.

  This film does not generate cracks in a long-term high-temperature and high-humidity environment, and can exhibit conductivity that does not deteriorate characteristics even at low humidity. Moreover, since it is excellent in flexibility, moisture permeability, and transparency, when used as an electrolyte membrane for fuel cells, secondary batteries, display elements, solar cells, etc., the troublesomeness of moisture management can be eliminated. Under a predetermined temperature condition, it exhibits higher ionic conductivity than a conventional perfluorosulfonic acid polymer.

Moreover, the base material with a conductive film according to the present invention has a conductivity in the range of approximately 10 ⁻² to 10 ⁻⁵ S / cm, which is necessary for a fuel cell. It can be used as a battery electrolyte.

The composition for forming a proton conductive film according to the present invention comprises (i) a polyimide silicone resin having a repeating unit represented by the following general formula (1), and (ii) a polymerizable acidic group containing a methacryloxy group or an acryloxy group. It includes a phosphate ester and (iii) a radical generator.

  Here, the polyimide silicone resin (i) has a repeating unit represented by the following general formula (1).

（式中、Ｘは四価の有機基、Ｙは二価の有機基、Ｚはオルガノポリシロキサン基を有する二価の有機基であり、ｐ及びｑはそれぞれ正の整数である。）

(Wherein X is a tetravalent organic group, Y is a divalent organic group, Z is a divalent organic group having an organopolysiloxane group, and p and q are each a positive integer.)

In this case, as X, for example, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic acid dihydrate, 4,4 And tetravalent organic groups derived from aromatic acid dianhydrides such as '-hexafluoropropylidenebisphthalic dianhydride and 3,3', 4,4'-diphenyl ether tetracarboxylic dianhydride, In particular, the following formulas (2), (3), (4), and (5) are used.
= Ph-C (CF ₃ ) ₂ -Ph = (2)
_{= Ph-SO 2 -Ph = (} 3)
= Ph-O-Ph = (4)
= Ph-CO-Ph = (5)
(However, Ph represents a benzene ring.)

  Moreover, when using a photoradical generator, the tetravalent organic group derived from an aliphatic tetracarboxylic dianhydride or an alicyclic tetracarboxylic dianhydride is preferable at the point which does not prevent light absorption. Examples of the aliphatic tetracarboxylic dianhydride include butane-1,2,3,4-tetracarboxylic dianhydride, pentane-1,2,4,5-tetracarboxylic dianhydride, and the like. Examples of the alicyclic tetracarboxylic dianhydride include 2,3,4-cyclobutanetetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, dicyclohexyl-3,4,3. ', 4'-tetracarboxylic dianhydride, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride Anhydrides, bicyclo [β, 2,2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and the like can be mentioned.

  1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, Fragrances such as 3,3a, 4,5,9b-hexahydro-5-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione An aliphatic tetracarboxylic dianhydride having a ring may be used. Furthermore, you may use the aromatic tetracarboxylic dianhydride which is excellent in heat resistance in the range which does not prevent the light absorption of a photoradical generator. As aromatic tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenyl ether tetracarboxylic acid And dianhydrides, 4,4′-hexafluoropropylidenebisphthalic dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, and the like. These tetracarboxylic dianhydrides can be used alone or in combination of two or more.

Examples of Y include divalent organic groups derived from various diamines. Specifically, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4 -(4-aminophenoxy) phenyl] hexafluoropropane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 1,4-bis (4-amino) Phenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2- Aromatic diamines such as bis (4-aminophenyl) propane, 3,3′-dihydroxy-4,4′-diaminobiphenyl, 2,2-bis (3-hydroxy-) Derived from diamines having functional groups other than amino groups, such as -aminophenyl) propane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, bis (3-carbonyl-4-aminophenyl) methane One of these may be used alone, or two or more may be used in combination. Particularly, as Y, 2,2- [2-hydroxy-3- (3,5- Methyl-4-amino) benzyl-5-methyl-1-diphenylmethane, or one represented by the following general formula (6) or (11) is preferred.
-Ph-O-B-O-Ph- (6)
-Ph (OH) - (D) a -Ph (OH) - (11)
(In the formula, B represents a group represented by the following formula (7), (8), (9) or (10)).
-Ph- (7)
_{-Ph-C (CH 3) 2} -Ph- (8)
_{-Ph-C (CF 3) 2} -Ph- (9)
-Ph-SO ₂ -Ph- (10)
(In the formula, Ph represents a benzene ring. D is —CH ₂ —, — (CH ₃ ) ₂ C— or — (CF ₃ ) ₂ C—, and a is 0 or 1).

  Furthermore, Z is preferably a divalent siloxane residue represented by the following general formula (12) derived from the diaminosiloxane of the following general formula (13), and one of these is used alone or two or more Can be used in combination.

（式中、Ｒ¹は炭素数１〜３のアルキル基、ビニル基又はフェニル基を示し、これらは同一であっても異なっていてもよい。好ましくはＲ¹の少なくとも１個、特に１〜ｂ／２個がビニル基である。ｂは０〜４０、好ましくは０〜２０の整数を表す。）

(Wherein R ¹ represents an alkyl group having 1 to 3 carbon atoms, a vinyl group or a phenyl group, which may be the same or different. Preferably, at least one of R ¹ , particularly 1 to b. / 2 are vinyl groups, and b represents an integer of 0 to 40, preferably 0 to 20.)

  The polyimide silicone resin preferably has a vinyl group in the side chain from the viewpoints of improving the strength of the film by crosslinking and preventing bleeding out of the phosphoric acid component due to reaction with the polymerizable phosphoric acid compound.

  The polyimide silicone resin having the unit of the formula (1) according to the present invention can be obtained by reacting the acid dianhydride with diamine and diaminosiloxane. In this case, the organosiloxane component in the polyimide silicone resin Is preferably 30% by mass or more, and more preferably 40% by mass or more. When the amount is less than 30% by mass, water permeability and compatibility of each component of the resulting composition are deteriorated. Moreover, although the upper limit is selected suitably, it is preferable that the ratio of an organosiloxane component is 90 mass% or less in a polyimide silicone resin, especially 80 mass% or less. Accordingly, in the above formula (1), p and q are positive integers, but it is preferable to select the organosiloxane component in the polyimide silicone resin within the above range, and q / (p + q) is 0.1. It is preferable that it is -0.95, especially 0.2-0.9.

  The weight average molecular weight in terms of polystyrene by GPC of the polyimide silicone resin is preferably 5,000 to 100,000, and particularly preferably 10,000 to 70,000. When the molecular weight is less than 5,000, the cured film obtained from the polyimide silicone resin composition may be fragile, and when the molecular weight exceeds 100,000, the compatibility with the acrylic compound may be deteriorated.

  The polyimide silicone resin may be produced by a known method. First, an acid dianhydride, a diamine and diaminopolysiloxane are charged in a solvent and reacted at a reaction temperature of 20 to 50 ° C. to obtain a polyimide resin precursor. A polyamic acid is produced. The obtained polyamic acid solution is preferably heated to a temperature of 80 to 200 ° C., particularly preferably 140 to 180 ° C., and a polyamic acid acid amide is subjected to a dehydration ring-closing reaction to obtain a polyimide silicone resin solution. . The solution is poured into a solvent such as water, methanol, ethanol, and acetonitrile to precipitate the produced polymer, and the precipitate is dried to obtain a polyimide silicone resin.

  Here, the total ratio of the diamine and the diaminopolysiloxane to the tetracarboxylic dianhydride is appropriately determined according to the molecular weight of the polyimide silicone resin to be produced, but preferably 0.95 to 1.05 in terms of molar ratio. Preferably it is the range of 0.98-1.02. Moreover, as a solvent used when manufacturing a polyimide silicone resin, N-methyl-2-pyrrolidone, cyclohexanone, (gamma) -butyrolactone, N, N- dimethylacetamide, etc. are mentioned.

  In addition, in order to adjust the molecular weight of the polyimide silicone resin, it is also possible to add a raw material of a monofunctional group such as phthalic anhydride or aniline. In this case, the amount of the monofunctional raw material added is preferably 2 mol% or less with respect to the polyimide silicone resin. It is also possible to perform imidization by raising the temperature of a solution obtained by adding an acetic anhydride / pyridine mixed solution to a polyamic acid solution to around 50 ° C.

Examples of the polymerizable acidic phosphoric acid ester containing the methacryloxy group or acryloxy group of the component (ii) used in the present invention include the phosmer series manufactured by Unichemical Co. That is, Phosmer M (acid phosphooxyethyl methacrylate), Phosmer CL (3 chloro 2-acid phosphoxypropyl methacrylate), Phosmer P (acid phosphoxypropyl methacrylate), Phosmer A (acid phosphoxyethyl acrylate), Phosmer PE (acid phospho) Xypolyoxyethylene glycol monomethacrylate), phosmer PP (acid phosphoxypolyoxypropylene glycol monomethacrylate), phosmer MH (methacryloyloxyethyl acid phosphate monoethanolamine half salt), phosmer DM (methacryloyloxyethyl acid phosphate) Dimethylaminoethyl methacrylate half salt), Phosmer DE (methacryloyloxyethyl acid phosphate diethyl ether) Roh ethyl methacrylate half salt), and the like. Examples of specific _{structure, 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, and two or more of them can be used as desired. Among these, CH ₂ ═C (CH ₃ ) COOCH ₂ CH ₂ OP (O) (OH) ₂ and CH ₂ ═CHCOOCH ₂ CH ₂ OP (O) (OH) ₂ are preferable in terms of compatibility and hardness. .

  In the total amount of the component (i) and the component (ii) in the composition of the present invention, the ratio of each component is within the range of 25 to 95% by mass, further 30 to 80% by mass as the solid component (i). It is preferable that the ratio of the component (ii) is in the range of 5 to 75% by mass, further 20 to 70% by mass as the solid content. When the proportion of the component (i) is less than 25% by mass, the hardness, heat resistance and water resistance tend to decrease. Further, when the proportion of the component (ii) is less than 5% by mass, the conductive function of the film tends to be insufficient. When the amount exceeding 75% by mass is added, the proportion of the component (i) is necessarily 25. It becomes less than mass%, and there exists a tendency for hardness, heat resistance, and water resistance to fall.

Furthermore, it is desirable to add the following “polyacid” to the composition of the present invention for the purpose of improving ionic conductivity in a low humidity environment.
“Polyacid” is a group of compounds of condensed oxygen acids (anionic metal polynuclear oxygen complexes) formed by condensation of oxygen acids of group V and group VI elements (V, Nb, Ta, Mo, W). Indicates. Such polyacids are basically composed of a combination of an octahedron and a tetrahedron with an oxygen atom at the apex centered on a skeleton / hetero atom. Polyacids made of oxyacids of these metals (skeleton atoms, addenda atoms) are called “isopolyacids”, and other oxygen acids of elements such as silicon (heteroatoms) are also incorporated. Things are called “heteropolyacids”. In particular, heteropolyacids have many Keggin-type structures represented by [XM ₁₂ O ₄₀ ] ^n- and Dawson-type (or Wells-Dawson-type) structures represented by [X ₂ M ₁₈ O ₆₂ ] ^n- . It is known to have isomers.

More specifically, phosphomolybdic acid; H ₃ [PMO ₁₂ O ₄₀ ] · nH ₂ O, silicomolybdic acid; H ₄ [SiMo ₁₂ O ₄₀ ] · nH ₂ O, phosphotungstic acid; H ₃ [PW ₁₂ O ₄₀ ] · nH ₂ O, silicotungstic acid; H ₄ [SiW ₁₂ O ₄₀ ] · nH ₂ O and the like (in this case, n is known to take a positive integer of 24 to 30). )

Such a polyacid exists as an anion, and in order to compensate for its negative charge, a cation such as proton (H ⁺ ) surrounds the periphery as a counter cation in the crystal, and an extraordinarily large amount of water of 24-30. It has been clarified from studies such as NMR that solvent molecules such as molecules are also present in the lattice and move very rapidly in the solid. Further, it is known that this crystal water once dehydrates once when heated to 300 ° C., but quickly condenses when left at room temperature under high humidity. It is presumed that such a property that should be called a crystal water hydrogen bond network with protons is incorporated into the silicic acid / phosphoric acid skeleton, and exhibits high conductivity even at low humidity.

  The ratio of the polyacid in the composition is preferably in the range of 5 to 50% by mass, more preferably in the range of 10 to 35% by mass as the solid content with respect to the total amount of the components (i) and (ii). If the amount is less than 5% by mass, the conductive properties under low humidity are not sufficiently expressed. If the amount exceeds 50% by mass, the strength of the film may be insufficient.

  In addition, a multifunctional monomer such as trimethylolpropane triacrylate or trimethylolpropane trimethacrylate may be added to the composition of the present invention in order to improve the strength of the film by crosslinking.

  In addition, in order to improve characteristics such as film strength and adhesion to the substrate, a silane alkoxide compound, particularly a silane coupling agent which is a silane alkoxide compound containing a functional group, or a hydrolyzate thereof, as necessary. Can be added to the composition. Examples of the silane alkoxide compound include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane as tetraalkoxysilane. Specific examples of the silane coupling agent having an organic substituent include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3- Glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxy Silane, 3-acryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-β- (aminoethyl) -3-aminopropyltrimethoxysilane, N-β- (a And minoethyl) -3-aminopropyltriethoxysilane.

  In particular, silane coupling agents include γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-acryloxy. Propylmethyldimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropylmethyldiethoxysilane, γ-acryloxypropyltriethoxysilane, and the like are preferable silane coupling agents.

  Here, the blending amount of the polyfunctional monomer and the silane alkoxide compound is preferably 30% by mass or less, particularly preferably 0.1 to 30% by mass, based on the total amount of the components (i) and (ii). If the amount is too large, it may become brittle and the film strength may decrease.

  The radical generator of component (iii) used in the present invention is added to form an insoluble film by crosslinking and curing the composition of the present invention. The radical generator used in the present invention is not limited as long as it reacts with a vinyl group or a (meth) acrylic compound and imparts crosslinking ability, and includes a thermal radical generator or a photoradical containing a compound that generates radicals. Examples of generators include photo radical generators, organic peroxides, and azo compounds selected from acetophenone derivatives, benzophenone derivatives, benzoin ether derivatives, and xanthone derivatives in terms of productivity and rapid curing. These can be used in combination.

  Specific examples of organic peroxides include benzoyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, cumene hydroperoxide, tert-butyl peroxyisopropyl monocarbonate, etc. Specific examples of azo compounds include azobisisobutyrate. Examples include rhonitrile, 2,2-azobis (2,4-dimethylvaleronitrile), and the like.

  Further, as a photo radical generator, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxy-cyclohexyl phenyl ketone, isobutylbenzoin Ether, benzoin methyl ether-1-thioxanthone, isopropylthioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- ( 4-morpholinophenyl) -butanone-1 and the like. Under the trade name, Lucilin TPO (acylphosphine oxide) manufactured by BASF, hydroxyketone (Dalcure 1173) manufactured by Ciba Specialty Chemicals Co., Ltd., Irgacure 907 (aminoketone) and the like can be easily obtained.

  The ratio of the radical generator may be any ratio as long as the resulting composition has fluidity, but the preferable ratio is that the amount of component (iii) is the total amount of all the compositions. If it is in the range of 0.1 to 10% by mass. If the proportion of component (iii) is less than 0.1% by mass, sufficient curing will not be performed, and the hardness and water resistance may be reduced. Etc. tend to be deteriorated.

  The composition for forming a conductive film of the present invention can be diluted with a solvent as necessary to adjust the film thickness of the protective film in order to improve coating properties, improve workability, and adjust the film thickness of the protective film. Is possible. In particular, in order to facilitate the homogenization of the polyimide silicone resin, the (meth) acrylic compound and the radical generator, a solvent is added, and the polyimide silicone resin of the present invention is removed by distilling off the solvent after being uniformly mixed. A composition can also be obtained.

  The solvent used at this time is preferably a solvent having a low boiling point, and examples thereof include solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, ethyl ether, and tetrahydrofuran. These may be used singly or in combination of two or more.

  In practical use of the polyimide silicone resin composition according to the present invention, the viscosity at 25 ° C. is preferably 10,000 Pa · s or less, more preferably 0.01 to 5 in view of ease of handling. 1,000 Pa · s, more preferably 0.1 to 1,000 Pa · s.

Next, the method for forming the conductive film according to the present invention will be specifically described.
The film is formed by applying the composition of the present invention by a wet thin film forming method such as a dipping method, a spinner method, a spray method, a roll coater method, or a flexographic printing method, and drying as necessary. The film can be formed from the composition on a substrate such as a film, sheet or other molded body made of glass, plastic, ceramic or the like. In addition, by selecting a fluorine-based film as a base material or using a base material coated with a fluorine-based film, coating it, cross-linking and insolubilizing it, forming a film, and then peeling off from the fluorine-based film, A self-supporting film can be formed. A polytetrafluoroethylene plate can be used as the fluorine-based film, and Aflex (manufactured by Asahi Glass Co., Ltd.) can be used as the fluorine-based coating film.

  Since the composition of the present invention contains a radical generator, it can be crosslinked by heating, crosslinked using electromagnetic waves such as ultraviolet rays, or when this silane alkoxide coexists, this condensation reaction. It is also possible to crosslink using Usually, the method using electromagnetic waves is an economically advantageous film-forming method because crosslinking proceeds from the surface in a short time, but it is difficult for light to reach the deep part, and is not suitable for thick film formation or high-concentration colored products. is there. Moreover, the method by heating requires sufficient time. In this way, by cross-linking using a plurality of different cross-linking methods, cross-linking can be advanced to a deep portion in a relatively short time, taking advantage of both, and there is no generation of cracks etc. while having high hardness, When a film is formed, a highly conductive substrate with a film can be formed.

Specifically, the substrate coated with the composition is heated at a temperature of 60 ° C. or higher and 220 ° C. or lower during drying or after drying, more preferably at a temperature of 80 ° C. or higher and 180 ° C. or lower, or an uncured film. It may be insolubilized by irradiating an electromagnetic wave such as an ultraviolet ray, an electron beam, an X-ray, or a γ ray having a shorter wavelength than visible light. Case of irradiation with ultraviolet light may be used a high-pressure mercury lamp, irradiation energy ultraviolet of wavelength of 365nm, 20~20,000mJ / cm ^2, more preferably by irradiation 50~5,000mJ / cm ² Can do. Alternatively, by combining irradiation with ultraviolet rays or the like and heat treatment, curing of the film forming component is promoted, and energy loss due to fuel permeability of the obtained film can be suppressed to a low level. In particular, in this method using different crosslinking mechanisms in combination, a thermal radical polymerization reaction, a photopolymerization reaction and a condensation reaction are used in combination, so that the crosslinking density can be increased and the film hardness can be increased.

  Maintaining the hardness of the membrane is important when used as an electrolyte in a fuel cell that uses methanol as the fuel, as it can reduce the “methanol crossover phenomenon” where methanol passes through the electrolyte membrane and reduces power generation efficiency. It is. By using polyimide silicone with siloxane containing vinyl group as the silicone component, it has the effect of imparting flexibility and moisture permeability to the material, and the ionic conductivity of the inorganic and organic hybrid obtained by curing It is presumed that the film is difficult to generate cracks while having high hardness and high conductivity.

  EXAMPLES Hereinafter, although a manufacture example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Production Example 1]
1,3,3a, 4,5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,1,3,3a, 4,5,9b in a flask equipped with a stirrer, thermometer and nitrogen displacement apparatus. 2-c] 30.0 g (0.1 mol) of furan-1,3-dione (hereinafter abbreviated as PI-DC), 250 g of N, N-dimethylacetamide, and 100 g of toluene were charged. Subsequently, 2,2 ′-{2-hydroxy-3- (3,5-methyl-4-amino) -benzyl-5-methyl} -diphenylmethane (hereinafter abbreviated as BAPP) in the flask. 35 g (0.025 mol) was added and the temperature of the reaction system was held at 50 ° C. for 3 hours. Furthermore, 64.88 g (0.075 mol) of diaminosiloxane (hereinafter abbreviated as AM-Vi-Si, where a + b is 9.5) is added dropwise at room temperature. Stir for 12 hours.
Next, after attaching a reflux condenser with a moisture receiver to the flask, 20.4 g of acetic anhydride and 26.4 g of pyridine were added, the temperature was raised to 50 ° C., and the temperature was maintained for 3 hours.
After cooling this solution to room temperature (25 ° C.), it was poured into methanol to precipitate a high molecular weight product, and the resulting precipitate was dried to obtain a polyimide silicone resin having a siloxane content of 61% by mass. It was.
The The infrared absorption spectrum of the resin was measured, the absorption does not appear attributable to polyamic acid and indicating the presence of unreacted functional groups, and confirming absorptions based on the imide group in 1770 cm ^-1 and 1710 cm ^-1. Moreover, it was 59,500 when the weight average molecular weight (polystyrene conversion) of this resin was measured by the gel permeation chromatography (GPC) which uses tetrahydrofuran as a solvent. In addition, the obtained resin was q / (p + q) = 0.8 in Formula (1).

[Examples and Comparative Examples]
The following were used as raw materials for the preparation of the conductive film forming composition.
(I) As the polyimide silicone resin, the polyimide silicone resin of Production Example 1 was dissolved in MIBK (methyl isobutyl ketone) and used as a 30% by mass solution.
(Ii) As a polymerizable acidic phosphoric acid ester containing a methacryloxy group, Phosmer M (acid phosphoxyethyl methacrylate) manufactured by Unichemical Co., Ltd. was used.
(Iii) As a polymerization initiator, a photopolymerization initiator, Dulcure 1173 (abbreviated as DC1173) manufactured by Ciba Geigy Co., Ltd. was used.
Further, phosphotungstic acid (abbreviated as PW) was used as the polyacid, and trimethylolpropane triacrylate (abbreviated as TMPTA) was used as the polyfunctional polymerizable monomer.
As a polyimide resin for comparison (comparison (i)), U-Varnish-A manufactured by Ube Industries, Ltd. was used as a 20% NMP (N-methylpyrrolidone) solution of polyamic acid as a polyimide precursor. A polyphosphoric acid manufactured by Wako Pure Chemical Industries, Ltd. was used.
As an ion conductive film for a comparative example, Nafion 112 made by Dupont was used.

[Example 1] Preparation of conductive film-forming composition and evaluation thereof Phosmer M50g, polyimide silicone resin 30% MIBK (methyl isobutyl ketone) solution 167g (polyimide silicone resin component 50g), DC1173 5g (film) 5% by mass in the components) was added and mixed with a rotator for 1 hour to prepare a conductive film forming composition.
The film-forming composition was applied to the glass surface, and air-dried at room temperature for 1 hour to form a film. The self-supporting film was prepared by applying to a glass plate surface covered with a 10 × 10 cm fluorine-based release film.
This was placed in an ultraviolet irradiation device (high pressure mercury lamp) manufactured by Igraphic, and UV-crosslinked with an irradiation energy of 1 J / cm ² in a 365 nm region measured with a UV meter (UVPF36). This formed a UV cross-linked conductive film. Furthermore, this was put in an electric oven and thermally crosslinked at 150 ° C./1 hour to form a UV-heat combined crosslinked conductive film.
The appearance of the film at this time was visually confirmed. The film hardness was measured by pencil hardness. The surface electrical resistance was measured with a surface resistance meter (manufactured by Mitsubishi Chemical Corporation: Hirestar UP MCP-HT450) in an environment of 25 ° C. and 55% RH. The results are shown in Table 1.
A conductive film was deposited on a 10 × 10 cm glass plate attached with a copper foil of 1 cm apart, and the electrical conductivity in a high temperature and high humidity state was evaluated in a constant temperature bath at 80 ° C. and 90% RH. The results are shown in Table 2.

[Comparative Example 1]
For comparison, using the above polyimide resin precursor (comparison (i)) in place of the polyimide silicone resin, the same operation as in Example 1 was performed, but Phosmer M and the polyimide resin were not compatible at all. A uniform film was not obtained.

[Comparative Example 2]
For comparison, when polyphosphoric acid was used instead of phosmer M and the same operation as in Example 1 was performed, the polyimide silicone resin and polyphosphoric acid were not compatible with each other, and a uniform film was not obtained.

[Comparative Example 3]
For comparison, the same operation as in Example 1 was carried out using polyimide silicone resin and Dalcure 1173 (DC1173) without using Phosmer M, but a transparent and uniform film was obtained. The conductivity of the film could not be measured.

[Example 2]
In the same manner as in Example 1, the amount of polyimide silicone resin and phosmer M was changed from 50/50 mass / mass% to 25/75 mass / mass%, and DC 1173 was used in exactly the same manner, and the same operation as in Example 1 was performed. As a result, a transparent and uniform film was obtained. The results are shown in Table 1.

[Example 3]
In the same manner as in Example 1, the amount of polyimide silicone resin and phosmer M was changed from 50/50 mass / mass% to 75/25 mass / mass%, and DC 1173 was used in exactly the same amount, and the same operation as in Example 1 was performed. As a result, a transparent and uniform film was obtained. The results are shown in Table 1.

[Example 4]
As a polyacid, 10 g of phosphotungstic acid was mixed with 50 g of Phosmer M and dissolved. To this mixture, 167 g of a 30% MIBK solution of polyimide silicone resin (50 g as a polyimide silicone resin component) and 5 g of DC1173 (5% by mass in the membrane component) were added and mixed for 1 hour with a rotator to form a conductive film. A composition was prepared.
The above composition for forming a conductive film was applied on the surface of glass, put in an ultraviolet irradiation device (high pressure mercury lamp), and UV-crosslinked at 1 J / cm ² to form a UV-crosslinked conductive film. This was put in an electric oven and thermally crosslinked at 150 ° C. for 1 hour to form a UV-heat combined crosslinked conductive film. The film appearance, pencil hardness, and surface electrical resistance at this time were measured in an environment of 25 ° C. and 55% RH. About the electroconductive film which affixed copper foil 1 cm apart, the electrical conductivity of a hot and humid state was evaluated in a thermostat of 80 degreeC and 90% RH. The results are shown in Table 2.

[Example 5]
In the same manner as in Example 4, only the amounts of polyimide silicone resin and phosmer M were changed from 50/50 mass / mass% to 25/75 mass / mass%, and phosphotungstic acid and DC1173 were used in exactly the same manner. When the same operation as in No. 4 was performed, a transparent and uniform film was obtained. The results are shown in Table 2.

[Example 6]
In the same manner as in Example 4, 25 g of TMPTA alone was added, and the same operation as in Example 4 was performed using exactly the same amounts of polyimide silicone resin, Phosmer M, PW, and DC1173. As a result, a transparent and uniform film was obtained. Obtained. The results are shown in Table 2.

[Comparative Example 4]
For comparison, the same operation was performed using Nafion 112. The results are shown in Table 2.

As a conclusion, a uniform conductive film was obtained only in the case of the combination of the polyimide silicone resin according to the present invention and Phosmer M.
Further, in the case of a system using polyacid (Table 2), the conductivity is greatly improved, and 3 × 10 ⁻² S / cm in a high temperature and high humidity state of 80 ° C. and 90% RH which is the use condition of the fuel cell. As a result, a conductivity higher than that of the Nafion film was obtained. Also, the pencil hardness is greatly improved from 3B to H and Nafion film of 6B or less, and a methanol crossover phenomenon hardly occurs, and a film having good hardness and conductivity that maintains high ionic conductivity is obtained. It was.

Claims (8)

(I) Polyimide silicone resin having a polystyrene-reduced weight average molecular weight of 5,000 to 100,000 by GPC having a repeating unit represented by the following general formula (1), and (ii) polymerization containing a methacryloxy group or an acryloxy group A composition for forming a proton conductive film, comprising: a basic acidic phosphate; and (iii) a radical generator.

(Wherein X is a tetravalent organic group, Y is a divalent organic group, Z is a divalent organic group having an organopolysiloxane group, and p and q are the weight average molecular weights of the polyimide silicone resin, respectively. (It is a positive integer having the above value, and q / (p + q) = 0.1 to 0.95.)   The content of the polymerizable acidic phosphate of component (ii) is in the range of 5 to 75 mass% with respect to the total amount of component (i) and component (ii). A composition for forming a proton conductive film.   Furthermore, the composition for proton conductive film formation of Claim 1 or 2 containing a polyacid.   The composition for forming a proton conductive film according to claim 3, wherein the content of the polyacid is 5 to 50% by mass with respect to the total amount of the components (i) and (ii).   The composition for forming a proton conductive film according to any one of claims 1 to 4, wherein Z of the polyimide silicone resin of component (i) is a divalent group having an organopolysiloxane group having a vinyl group in a side chain. object. Furthermore, the proton conductive film formation of any one of Claims 1-5 which contains 0.1-30 mass% of polyfunctional monomers or a silane alkoxide compound with respect to the total amount of (i) and (ii) component. Composition.   A film formed by applying the composition for forming a proton conductive film according to any one of claims 1 to 6 to a substrate, is heated at a temperature of 60 ° C or higher and 220 ° C or lower, or has a wavelength longer than visible light. A method for forming a conductive film, which comprises irradiating electromagnetic waves such as short ultraviolet rays, electron beams, X-rays, γ rays, or the like, or using these in combination to crosslink and insolubilize.   A film formed by applying the composition for forming a proton conductive film according to any one of claims 1 to 6 on a substrate coated with a fluorine-based film is formed by crosslinking and insolubilizing the film, A conductive self-supporting film that is peeled off from a fluorine-based film.