Thermosetting resin composition, adhesive sheet, double-sided adhesive sheet, and fuel cell

Abstract

To provide an adhesive sheet and a double-sided adhesive sheet which have excellent adhesion, a fuel cell which is sealed with the adhesive sheet or the double-sided adhesive sheet, and a thermosetting resin composition which is usable as a composition constituting the adhesive sheet and the double-sided adhesive sheet.SOLUTION: A thermosetting resin composition contains acid-modified polyolefin having a melting point of 100°C or lower, polycarbodiimide having a plurality of carbodiimide groups, and particles constituted of a resin.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a thermosetting resin composition, an adhesive sheet, a double-sided adhesive sheet, and a fuel cell. [Background technology]

[0002] A fuel cell, typified by a polymer electrolyte fuel cell, has a configuration in which multiple power-generating cells are stacked. A power-generating cell (hereinafter simply referred to as a "cell") has a configuration in which an anode electrode, an electrolyte membrane, and a cathode electrode are stacked in this order. A pair of separators is provided to sandwich the cell to protect it. In this cell, a hydrogen-containing gas is supplied to the anode electrode from outside the cell, and an oxygen-containing gas is supplied to the cathode electrode from outside the cell. A sheet is provided to seal the gap between the outermost separators of the cell to prevent gas leakage from the cell. This sheet is made of a resin composition. The separator is made of a metal material such as stainless steel (Steel Use Stainless, hereinafter also abbreviated as SUS). The sheet is required to have excellent adhesion to the metal material that constitutes the separator.

[0003] Fuel cells are used as a power source for fuel cell vehicles, which are an example of electric vehicles. The fuel cells installed in fuel cell vehicles are exposed to cooling water (also called coolant liquid) whose main component is ethylene glycol. The temperature of this coolant liquid can rise to, for example, 70°C to 120°C depending on the usage conditions. For this reason, there is a demand for a sheet whose adhesive strength with the separator does not decrease over a long period of time, even when exposed to high-temperature coolant liquid of 70°C to 120°C.

[0004] Patent Document 1 discloses an adhesive composition that can be used as a sheet material. Specifically, Patent Document 1 discloses an adhesive composition that contains polycarbodiimide and an organic solvent, and further contains a crystalline acid-modified polyolefin having an acid value of 10 to 50 mgKOH / g, or an acid-modified chlorinated polyolefin having an acid value of 10 to 50 mgKOH / g and a chlorine content of 5 to 40 mass%. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2015 / 033703 Summary of the Invention [Problem to be solved by the invention]

[0006] When a sheet made of this adhesive composition is exposed to a high-temperature coolant for a long period of time, the sheet may partially dissolve, and this dissolution may reduce the adhesive strength between the sheet and the separator.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an adhesive sheet and double-sided adhesive sheet having excellent adhesive properties, a fuel cell sealed with an adhesive sheet or double-sided adhesive sheet, and a thermosetting resin composition that can be used as a composition constituting the adhesive sheet and double-sided adhesive sheet. [Means for solving the problem]

[0008] The present invention is as follows.

[0009] [1] An acid-modified polyolefin having a melting point of 100°C or less; a polycarbodiimide having a plurality of carbodiimide groups; Particles made of resin, Thermosetting resin composition.

[0010] [2] The thermosetting resin composition according to [1] above, wherein the acid-modified polyolefin has a carboxy group.

[0011] [3] The thermosetting resin composition according to [2] above, wherein the polycarbodiimide contains 0.1 to 8.0 equivalents of carbodiimide groups per equivalent of the carboxyl groups.

[0012] [4] The thermosetting resin composition according to any one of [1] to [3] above, wherein the acid-modified polyolefin has an acid value of 1 mgKOH / g or more and 40 mgKOH / g or less.

[0013] [5] The thermosetting resin composition according to any one of [1] to [4] above, wherein the resin is at least one resin selected from the group consisting of acrylic resins, styrene resins, and urethane resins.

[0014] [6] The thermosetting resin composition according to any one of [1] to [5] above, wherein the content of the particles is 1.0 part by mass or more and 200 parts by mass or less per 100 parts by mass of the acid-modified polyolefin.

[0015] [7] An adhesive sheet comprising the thermosetting resin composition according to any one of [1] to [6] above.

[0016] [8] Film and and adhesive layers formed on both sides of the film, A double-sided adhesive sheet, wherein the adhesive layer is composed of the thermosetting resin composition according to any one of [1] to [6] above.

[0017] [9] The double-sided adhesive sheet according to [8] above, wherein the film is at least one film selected from the group consisting of polyethylene film, unstretched polypropylene film, stretched polypropylene film, polyethersulfone film, polyimide film, polyamideimide film, polyethylene naphthalate film, polyether ether ketone film, and polyphenylene sulfide film.

[0018]

[10] The double-sided adhesive sheet according to [8] or [9] above, wherein the thickness of the film is 12 μm or more and 200 μm or less.

[0019]

[11] an electrolyte membrane; an anode electrode laminated on one surface of the electrolyte membrane; a cathode electrode laminated on the other surface of the electrolyte membrane; a first separator that is larger than the anode electrode and is provided on the other surface of the anode electrode that is opposite to the surface on which the electrolyte membrane is laminated; a second separator provided on the other surface of the cathode electrode opposite to the surface on which the electrolyte membrane is laminated, the second separator being larger than the cathode electrode; A fuel cell in which a first inner peripheral surface, which is the peripheral edge of one surface of the first separator on which the anode electrode is laminated, faces a second inner peripheral surface, which is the peripheral edge of one surface of the second separator on which the cathode electrode is laminated, and the space between the first inner peripheral surface and the second inner peripheral surface is sealed with the adhesive sheet described in [7] above or the double-sided adhesive sheet described in [8] above.

[0020]

[12] The fuel cell according to

[11] above, wherein the first separator and the second separator are made of stainless steel or titanium.

[0021]

[13] The fuel cell according to

[12] above, wherein the adhesive strength between the adhesive sheet according to [7] above and the first separator or the second separator after immersion in cooling water at 120°C for 1000 hours is 10 N / cm or more.

[0022]

[14] The fuel cell according to

[12] above, wherein the adhesive strength between the double-sided adhesive sheet according to [8] above and the first separator or the second separator after immersion in cooling water at 120°C for 1000 hours is 10 N / cm or more. [Effects of the Invention]

[0023] According to the present invention, it is possible to provide an adhesive sheet and double-sided adhesive sheet having excellent adhesive properties, a fuel cell sealed with an adhesive sheet or double-sided adhesive sheet, and a thermosetting resin composition that can be used as a composition constituting the adhesive sheet and double-sided adhesive sheet. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a top view of a polymer electrolyte fuel cell, which is an example of a fuel cell according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a polymer electrolyte fuel cell taken along the line II-II shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, a thermosetting resin composition, an adhesive sheet, a double-sided adhesive sheet, and a fuel cell, which are modes for carrying out the present invention (hereinafter referred to as embodiments), will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following content. The present invention can be practiced by appropriately modifying it within the scope of its gist. Parts by mass refer to, for example, the parts by mass of the resin alone, excluding volatile components such as organic solvents contained in the resin, or the parts by mass of non-volatile components.

[0026] [Thermosetting resin composition] The thermosetting resin composition according to the embodiment includes an acid-modified polyolefin, a polycarbodiimide, and particles. Such a thermosetting resin composition can be suitably used as a resin composition for forming an adhesive sheet or a double-sided adhesive sheet having excellent adhesive properties.

[0027] Components contained in the thermosetting resin composition of the embodiment will be described below.

[0028] (acid-modified polyolefin) The acid-modified polyolefin contained in the thermosetting resin composition of the embodiment is a polyolefin acid-modified with at least one compound containing an acidic functional group and a derivative of this compound. Polyolefins are polymers obtained by polymerizing olefin monomers such as ethylene monomers, butylene monomers, propylene monomers, and / or isoprene monomers. Examples of polyolefins include polymers composed of one type of monomer and polymers composed of two or more types of monomers. One of the monomers in a polymer composed of two or more types of monomers may be, for example, a radically polymerizable acrylic monomer or vinyl monomer. Examples of polymers include polymers composed of one type of monomer and polymers composed of two or more types of monomers, i.e., random copolymers, alternating copolymers, and block copolymers.

[0029] Examples of compounds containing an acidic functional group include α,β-unsaturated carboxylic acids such as maleic acid, itaconic acid, and citraconic acid. Examples of derivatives of compounds containing an acidic functional group include acid anhydrides of α,β-unsaturated carboxylic acids. Examples of acidic functional groups include carboxy groups.

[0030] The polyolefin may be acid-modified using a compound containing one or more acidic functional groups, or may be acid-modified using a derivative of a compound containing one or more acidic functional groups, or may be acid-modified using one or more compounds containing acidic functional groups and one or more derivatives of the compound.

[0031] Examples of methods for acid-modifying polyolefins include a method in which maleic acid or a derivative thereof is added to a vessel containing an olefin monomer such as an ethylene monomer, a butylene monomer, a propylene monomer, and / or an isoprene monomer, followed by polymerization to obtain an acid-modified polyolefin; and a method in which maleic acid or a derivative thereof is added to a vessel containing a polyolefin that has not been acid-modified, followed by graft polymerization to obtain an acid-modified polyolefin.

[0032] The acid value of the acid-modified polyolefin is preferably 1 mgKOH / g or more and 40 mgKOH / g or less, more preferably 5 mgKOH / g or more and 40 mgKOH / g or less, and even more preferably 10 mgKOH / g or more and 30 mgKOH / g or less, from the viewpoint of exhibiting excellent adhesion between the adhesive sheet or double-sided adhesive sheet of the embodiment and a member made of a metal material.

[0033] The weight average molecular weight (Mw) of the acid-modified polyolefin is preferably 50,000 or more and 500,000 or less, and more preferably 100,000 or more and 400,000 or less, from the viewpoint of exhibiting excellent adhesion between the adhesive sheet or double-sided adhesive sheet of the embodiment and a member made of a metal material, and from the viewpoint of suppressing dissolution of the adhesive sheet or double-sided adhesive sheet of the embodiment when exposed to coolant liquid.

[0034] The melting point (Tm) of the acid-modified polyolefin is 100°C or lower from the viewpoint of improving the processability of the adhesive sheet and double-sided adhesive sheet of the embodiment. The melting point (Tm) of the acid-modified polyolefin is preferably 40°C or higher and 100°C or lower, more preferably 50°C or higher and 90°C or lower, from the viewpoint of improving the processability of the adhesive sheet and double-sided adhesive sheet of the embodiment and of exhibiting excellent adhesive properties even when exposed to a high-temperature coolant. The melting point can be measured using a differential scanning calorimeter (DSC).

[0035] Examples of commercially available acid-modified polyolefins that can be used in the embodiment include Auroren (registered trademark) manufactured by Nippon Paper Industries Co., Ltd., Modic (registered trademark) manufactured by Mitsubishi Chemical Corporation, and Hi-Loss-X (registered trademark) manufactured by Seiko PMC Corporation.

[0036] (Polycarbodiimide) The polycarbodiimide contained in the thermosetting resin composition of the embodiment is a compound having multiple carbodiimide groups. The carbodiimide equivalent is preferably 100 g / eq or more and 700 g / eq or less, and more preferably 150 g / eq or more and 500 g / eq or less. When the polycarbodiimide has the above-mentioned carbodiimide equivalent, excellent adhesion can be achieved between the adhesive sheet or double-sided adhesive sheet of the embodiment and a member made of a metal material. In addition, the crosslink density of the cured thermosetting resin composition can be increased, preventing the penetration of coolant into the thermosetting resin composition. Furthermore, the cured thermosetting resin composition can be made resistant to dissolution by coolant. Here, the carbodiimide equivalent refers to the value obtained by dividing the molecular weight of the polycarbodiimide by the number of carbodiimide groups contained in the polycarbodiimide.

[0037] The thermosetting resin composition of the present embodiment preferably contains 0.1 to 8.0 equivalents of polycarbodiimide carbodiimide groups relative to 1 equivalent of carboxy groups in the acid-modified polyolefin, and more preferably 0.5 to 2.0 equivalents of polycarbodiimide carbodiimide groups. By including the above-mentioned equivalents of carbodiimide groups in the thermosetting resin composition, the crosslink density of the cured thermosetting resin composition can be increased. This can prevent the penetration of coolant into the thermosetting resin composition. Furthermore, the cured thermosetting resin composition can exhibit resistance to dissolution by coolant.

[0038] The polycarbodiimide may be used alone or in any combination of two or more kinds of polycarbodiimides.

[0039] Commercially available polycarbodiimides include, for example, Carbodilite (registered trademark) manufactured by Nisshinbo Chemical Inc.

[0040] Polycarbodiimides can be obtained by subjecting aromatic or aliphatic diisocyanates and / or triisocyanates to a condensation reaction accompanied by the removal of carbon dioxide.

[0041] Examples of isocyanates used in this case include hexamethylene diisocyanate (HDI), hydrogenated xylylene diisocyanate (HXDI), xylylene diisocyanate (XDI), 2,2,4-trimethylhexamethylene diisocyanate (TMHDI), 1,12-diisocyanatododecane (DDI), norbornane diisocyanate (NBDI), and 2,4-bis-(8-isocyanatooctyl)-1,3-dioctylcyclobutane (OCDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), tetramethylxylylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), and compounds derived from these.

[0042] Examples of the compound derived from the isocyanate include a diisocyanate nurate, a trimethylolpropane adduct, a biuret-type compound, a prepolymer having an isocyanate residue, a uretdione having an isocyanate residue, an allophanate, or a complex thereof. Here, the prepolymer having an isocyanate residue refers to a low molecular weight polymer obtained from a diisocyanate and a polyol.

[0043] The above-mentioned isocyanates may be used singly or in combination of two or more kinds.

[0044] (particles composed of resin) The particles contained in the thermosetting resin composition of the embodiment are made of a resin. From the viewpoint of heat resistance, the resin constituting the particles is at least one resin selected from the group consisting of acrylic resins, styrene resins, and urethane resins. This allows the thermosetting resin composition to exhibit dissolution resistance in coolant liquid after curing.

[0045] From the viewpoint of heat resistance, the decomposition temperature of the resin constituting the particles is preferably 200°C or higher, more preferably 250°C or higher. This makes it difficult for the particles to undergo thermal decomposition even when the thermosetting resin composition is exposed to a high-temperature atmosphere, for example, 90°C or higher. The decomposition temperature is the temperature at which the tangent line of the TG (thermogravimetry) curve, where there is no initial weight loss or where there is a gradual weight loss, intersects with the tangent line where the sample weight has decreased by 10%. The TG curve can be measured using a thermogravimetric differential thermal analyzer.

[0046] The particle surfaces preferably contain isocyanate groups, hydroxyl groups, or carboxyl groups to enhance adhesion to acid-modified polyolefins and / or polycarbodiimides. This allows the thermosetting resin composition to exhibit resistance to dissolution in coolant liquid after curing. Furthermore, adhesive sheets or double-sided adhesive sheets made from the thermosetting resin composition have high adhesive properties to components made of metal materials, such as separators.

[0047] The average particle diameter (D50) of the particles is preferably 50% or less of the thickness of the adhesive sheet of the embodiment or the thickness of the adhesive layer constituting the double-sided adhesive sheet of the embodiment. This provides the adhesive sheet or double-sided adhesive sheet with excellent surface smoothness. Furthermore, it is possible to improve the adhesion between the adhesive sheet or double-sided adhesive sheet and a component made of a metal material, such as a separator. Here, the average particle diameter (D50) of the particles refers to the particle diameter when the smallest particles are counted first in a volume-based particle size distribution and the cumulative total reaches 50% of the total volume. The average particle diameter (D50) of the particles can be determined by a laser diffraction particle size distribution measurement method.

[0048] The content of the particles is preferably 1.0 to 200 parts by mass, more preferably 2.0 to 110 parts by mass, and even more preferably 5.0 to 50 parts by mass, per 100 parts by mass of the acid-modified polyolefin. This allows the thermosetting resin composition to exhibit resistance to dissolution in coolant after curing. Furthermore, adhesive sheets or double-sided adhesive sheets made of the thermosetting resin composition can exhibit high adhesiveness to components made of metal materials, such as separators.

[0049] The particles may be of one type alone or in combination of two or more types.

[0050] The particles can be obtained by a suspension polymerization method, a seed polymerization method, an emulsion polymerization method, or the like.

[0051] Examples of commercially available resin particles include crosslinked acrylic particles and crosslinked styrene particles manufactured by Soken Chemical & Engineering Co., Ltd., and Art Pearl (registered trademark) manufactured by Negami Chemical Industrial Co., Ltd.

[0052] (Other ingredients) Additives may be added to the thermosetting resin composition of the embodiment as long as they do not impair the properties of the thermosetting resin composition. Examples of additives include dispersants, softeners, heat aging inhibitors, and silane coupling agents.

[0053] The thermosetting resin composition of the embodiment can be obtained by mixing predetermined amounts of the above-described materials in a container. In order to mix the thermosetting resin composition uniformly, an organic solvent such as methyl ethyl ketone or toluene may be added.

[0054] [Adhesive sheet] Next, the configuration of the adhesive sheet of the embodiment will be described. The adhesive sheet of the embodiment is composed of the thermosetting resin composition of the embodiment. The thickness of the adhesive sheet of the embodiment is, for example, preferably 5 μm or more and 300 μm or less, and more preferably 10 μm or more and 300 μm or less. This allows the adhesive sheet of the embodiment to be tightly adhered to the surface of a metal member processed into a desired shape, such as a separator, without any gaps. Furthermore, the adhesive sheet of the embodiment having the above-mentioned thickness has excellent handleability. Note that the adhesive sheet of the embodiment can be used alone. It can also be used by bonding the adhesive sheet to both sides of a film serving as a core material. To distinguish it from the adhesive sheet, in the double-sided adhesive sheet described below, the adhesive sheets bonded to both sides of the film serving as a core material are also referred to as adhesive layers.

[0055] The adhesive sheet can be obtained, for example, by the following procedure. The particles composed of an acid-modified polyolefin, a polycarbodiimide, and a resin are mixed in the amounts described above in a container to obtain a thermosetting resin composition. The obtained thermosetting resin composition is applied to a release film using, for example, an application device to form a resin layer composed of the thermosetting resin composition. The formed resin layer is then heated, for example, at a temperature of 120°C to 180°C for 2 to 10 minutes. After cooling, the release film is peeled off from the resin layer to obtain an adhesive sheet. The cured state of the obtained adhesive sheet is such that the curing reaction of the thermosetting resin composition has progressed partway.

[0056] Examples of coating devices used when forming the resin layer include die coaters and comma coaters. Examples of film materials used when forming the resin layer include polyethylene, polypropylene, polyimide, polyamideimide, polyethylene naphthalate, and polyethylene terephthalate. From the viewpoint of facilitating lamination and peeling of the release film, the thickness of the release film is preferably, for example, 12 μm to 100 μm, more preferably 25 μm to 100 μm, and even more preferably 50 μm to 100 μm. Furthermore, from the viewpoint of facilitating peeling of the release film from the resin layer, a release treatment may be applied to the surface of the release film. Examples of treatment agents for the release treatment include silicone-based treatment agents and fluorine-based treatment agents.

[0057] After forming the resin layer on the release film, another release film may be attached to the surface of the resin layer opposite to the surface on which the release film is provided, while heating, thereby smoothing both surfaces of the resin layer.

[0058] Furthermore, by further promoting the curing reaction of the obtained adhesive sheet, high adhesive strength is exhibited in an atmosphere of 95° C., as described below. Heating conditions for promoting the curing reaction include preferably 50° C. to 100° C. and 24 hours to 240 hours, more preferably 60° C. to 90° C. and 96 hours to 192 hours.

[0059] [Double-sided adhesive sheet] Next, the configuration of the double-sided adhesive sheet of the embodiment will be described. The double-sided adhesive sheet of the embodiment is composed of a film as a core material and adhesive layers formed on both sides of the film. The adhesive layers are composed of the thermosetting resin composition of the embodiment.

[0060] The film constituting the double-sided adhesive sheet has heat resistance and hydrolysis resistance. Examples of the film constituting the double-sided adhesive sheet include at least one film selected from the group consisting of polyethylene film, unstretched polypropylene film, oriented polypropylene film, polyethersulfone film, polyimide film, polyamideimide film, polyethylene naphthalate film, polyetheretherketone film, and polyphenylene sulfide film. From the viewpoints of heat resistance and resistance to dissolution in coolant, unstretched polypropylene film, oriented polypropylene film, polyethersulfone film, or polyphenylene sulfide film is preferred. From the viewpoint of adhesion between the adhesive layer constituting the double-sided adhesive sheet and the film, unstretched polypropylene film is preferred.

[0061] The thickness of the film is, for example, preferably from 12 μm to 200 μm, more preferably from 20 μm to 200 μm, and even more preferably from 50 μm to 150 μm. When the film has the above thickness, the double-sided adhesive sheet of the embodiment has excellent handleability.

[0062] The thickness of the adhesive layer is, for example, preferably from 5 μm to 300 μm, more preferably from 10 μm to 300 μm, and even more preferably from 15 μm to 300 μm, which allows the double-sided adhesive sheet of the embodiment to be tightly adhered to the surface of a metal member, such as a separator, that has been processed into a desired shape.

[0063] The thickness of the double-sided adhesive sheet is preferably 22 μm or more and 800 μm or less, and more preferably 32 μm or more and 800 μm or less.

[0064] The double-sided adhesive sheet can be obtained, for example, by the following procedure. First, two adhesive sheets of the embodiment with a release film attached to one side are prepared. Next, the adhesive sheet of the embodiment is laminated on both sides of the film so that the resin surface and the film are in contact with each other to obtain a laminate. This laminate is heated and pressurized at a temperature of 50°C to 160°C, at a pressure of 0.5 MPa to 3.0 MPa, for a time of 0.1 seconds to 10 seconds. After cooling, the film is peeled from the resin layer to obtain a double-sided adhesive sheet.

[0065] Furthermore, by further promoting the curing reaction of the obtained double-sided adhesive sheet, high adhesive strength is exhibited in an atmosphere at 95° C. Heating conditions for promoting the curing reaction include preferably 50° C. or higher and 100° C. or lower, and 24 hours or higher and 240 hours or lower, and more preferably 60° C. or higher and 90° C. or lower, and 96 hours or higher and 192 hours or lower.

[0066] The resulting adhesive sheet or double-sided adhesive sheet can be used to bond separators that constitute a fuel cell. Heating conditions for bonding include, for example, 50°C to 160°C, 0.5 MPa to 3.0 MPa, and 1 second to 180 seconds. After bonding separators that constitute a fuel cell using the adhesive sheet or double-sided adhesive sheet of this embodiment under the above heating conditions, it is preferable to further heat the sheet at 60°C to 120°C for 12 hours to 100 hours. This further enhances the adhesion between the separators via the adhesive sheet or double-sided adhesive sheet of this embodiment.

[0067] [Polymer electrolyte fuel cell] An example of a fuel cell according to the embodiment is a polymer electrolyte fuel cell. A polymer electrolyte fuel cell 10 using an adhesive sheet 60 according to the embodiment will be described as an example. As shown in FIG. 1, the polymer electrolyte fuel cell 10 includes a separator 21 having a plurality of grooves 23, a power generation cell 70, a separator 22 (not shown), and an adhesive sheet 60. As shown in FIG. 2, the power generation cell 70 includes an anode electrode 30, an electrolyte membrane 50, and a cathode electrode 40. The periphery of the polymer electrolyte fuel cell 10 is filled with cooling water (not shown) for cooling the polymer electrolyte fuel cell 10.

[0068] The anode electrode 30 is composed of an anode catalyst layer 31 and a gas diffusion layer 32. The anode catalyst layer 31 is laminated on one surface of the electrolyte membrane 50. The gas diffusion layer 32 is laminated on the other surface of the anode catalyst layer 31, which is the surface opposite to the surface on which the electrolyte membrane 50 is laminated. That is, in order from closest to the electrolyte membrane 50, the anode catalyst layer 31 and the gas diffusion layer 32 are laminated on the electrolyte membrane 50.

[0069] The cathode electrode 40 is composed of a cathode catalyst layer 41 and a gas diffusion layer 42. The cathode catalyst layer 41 is laminated on one surface of a polymer electrolyte membrane 50. The gas diffusion layer 42 is laminated on the other surface of the cathode catalyst layer 41, which is the surface opposite to the surface on which the electrolyte membrane 50 is laminated. That is, in order from closest to the electrolyte membrane 50, the cathode catalyst layer 41 and the gas diffusion layer 42 are laminated on the electrolyte membrane 50.

[0070] The anode catalyst layer 31 has a catalytic function that promotes the oxidation reaction of hydrogen. As the anode catalyst layer 31, for example, a carbon support with a platinum loading of 50 wt % can be used. Specifically, TEC10E50E (manufactured by Tanaka Kikinzoku Kogyo K.K.) can be used.

[0071] The cathode catalyst layer 41 has a catalytic function of promoting the reduction reaction of oxygen. As the cathode catalyst layer 41, for example, a carbon support with a platinum loading of 50 wt % can be used. Specifically, TEC10E50E (manufactured by Tanaka Kikinzoku Kogyo K.K.) can be used.

[0072] The gas diffusion layer 32 has a function of diffusing hydrogen (not shown) supplied from the outside throughout the anode catalyst layer 31. The gas diffusion layer 42 has a function of diffusing oxygen (not shown) supplied from the outside throughout the cathode catalyst layer 41. The gas diffusion layer 32 and the gas diffusion layer 42 may be made of carbon paper whose surface has been treated to be water repellent. A specific example is SGL24-BCH (manufactured by SGL Carbon).

[0073] The electrolyte membrane 50 is made of, for example, a polymer electrolyte membrane. When the solid polymer fuel cell 10 is, for example, a proton exchange type solid polymer fuel cell, the electrolyte membrane 50 converts protons (H + ) is passed through.

[0074] The separator 21 is provided on one surface of the anode electrode 30, opposite to the surface on which the electrolyte membrane 50 is laminated. The separator 21 has a plurality of grooves 23 on one surface through which cooling water (coolant liquid) (not shown) flows, and a plurality of grooves 25 on the other surface through which hydrogen (not shown) supplied from the outside flows. The separator 21 is larger than the anode electrode 30. The separator 21 has an inner edge surface 27 on its periphery for bonding to the inner edge surface 28 of the opposing separator 22 via an adhesive sheet 60. The separator 21 is made of a metal material such as stainless steel or titanium. The inner edge surface 27 corresponds to a first inner edge surface.

[0075] The separator 22 is provided on one surface of the cathode electrode 40, opposite to the surface on which the electrolyte membrane 50 is laminated. The separator 22 has a plurality of grooves 24 on one surface through which cooling water (coolant liquid), not shown, flows, and a plurality of grooves 26 on the other surface through which oxygen, not shown, supplied from the outside, flows. The separator 22 is larger than the cathode electrode 40. The separator 22 has an inner edge surface 28 on its periphery for bonding to the inner edge surface 27 of the opposing separator 21 via an adhesive sheet 60. The separator 22 is made of a metal material, such as stainless steel or titanium. The inner edge surface 28 corresponds to a second inner edge surface.

[0076] The inner edge surface 27 and the inner edge surface 28 are bonded together with an adhesive sheet 60. In addition, the gap between the periphery of the separator 21 and the periphery of the separator 22 is sealed with the adhesive sheet 60. This prevents hydrogen and oxygen from leaking from the power generation cell 70. It also prevents the cooling water (coolant liquid) used to cool the polymer electrolyte fuel cell 10 from entering the power generation cell 70.

[0077] Furthermore, adhesive sheet 60 is configured with the adhesive sheet of the embodiment or a double-sided adhesive sheet. As a result, even if high-temperature cooling water (coolant liquid) comes into contact with adhesive sheet 60, adhesive sheet 60 does not dissolve and can bond inner edge surface 27 and inner edge surface 28 together, thereby sealing the gap between inner edge surface 27 and inner edge surface 28.

[0078] When stacking multiple solid polymer fuel cells 10, the adhesive sheet or double-sided adhesive sheet of the embodiment may be used, for example, to fix one solid polymer fuel cell 10 to another solid polymer fuel cell 10. [Example]

[0079] 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 in any way.

[0080] The following materials were used as components contained in the thermosetting resin compositions of the Examples and Comparative Examples. (acid-modified polyolefin) Auroren 550S (manufactured by Nippon Paper Industries Co., Ltd.), melting point 80°C, acid value 10 mg KOH / g. Unistall H-200 (Mitsui Chemicals), melting point 105°C, acid value 10 mg KOH / g. (styrene-based thermoplastic elastomer) Tuftec M1913 (manufactured by Asahi Kasei Corporation), no melting point (amorphous type), acid value 10 mg KOH / g. (Carboxy group-containing acrylic polymer) SK Dyne 1838 (manufactured by Soken Chemical Engineering Co., Ltd.), no melting point (amorphous type), acid value 62 mg KOH / g.

[0081] (Polycarbodiimide) Carbodilite V-09GB (Nisshinbo Chemical Co., Ltd.), multifunctional type, carbodiimide equivalent weight 200 g / eq. (carbodiimide) Stabaxol I-LF (Rhein Chemie), monofunctional type, carbodiimide equivalent weight 360 g / eq. (epoxy resin) (1) EHPE3150 (manufactured by Daicel Corporation), epoxy equivalent 180 g / eq. (2) Unistall HD-02A (N100) (Mitsui Chemicals, Inc.), epoxy equivalent weight 200 g / eq.

[0082] (Particles composed of acrylic resin) MX-1000 (manufactured by Soken Chemical Co., Ltd.), average particle size 10 μm (D50). (Particles composed of styrene-based resin) SX-500H (manufactured by Soken Chemical Co., Ltd.), average particle size 5.0 μm (D50). (Particles composed of urethane resin) Art Pearl C-600T (manufactured by Negami Chemical Industries), average particle size 10 μm (D50).

[0083] Example 1 (Preparation of Thermosetting Resin Composition) A reaction vessel was charged with 3.6 parts by mass of Carbodilite V-09GB, 12.5 parts by mass of MX-1000, and 25 parts by mass of toluene, followed by stirring at room temperature until uniform. 100 parts by mass of Auroren 550S was then added to the reaction vessel and stirred until uniform, yielding a thermosetting resin composition. Auroren 550S was used by dissolving 100 parts by mass of Auroren 550S in 667 parts by mass of toluene. The equivalent of the carbodiimide group in Carbodilite V-09GB (polycarbodiimide) relative to 1 equivalent of the carboxyl group in Auroren 550S (acid-modified polyolefin) was 1 equivalent (1 eq).

[0084] (Preparation of double-sided adhesive sheet) Using a comma coater, the thermosetting resin composition was applied to the release-treated surface of a 50 μm-thick release PET film (PF 50GSY40 manufactured by Lintec Corporation) so that the thickness of the resin layer after drying would be 25 μm. The composition was then dried at 130 ° C for 3 minutes to obtain an adhesive layer with a release PET film. Another adhesive layer with a release PET film was also prepared using the same method.

[0085] Next, a 100 μm thick unstretched polypropylene film (RXC-23 manufactured by Mitsui Chemicals Tocello) was prepared as the film constituting the double-sided adhesive sheet. The previously obtained adhesive layer was laminated on one side of the film so that the resin surface was in contact, and then heated and pressed. The heating and pressing conditions were 70°C, 0.5 MPa, and 10 seconds. Next, another adhesive layer was laminated on the other side of the film so that the resin surface was in contact, and then heated and pressed. The heating and pressing conditions were 120°C, 1 MPa, and 10 seconds. After cooling, a double-sided adhesive sheet laminated with a release PET film was obtained. The double-sided adhesive sheet used in the adhesive strength measurement sample described below was heated at 70°C for 144 hours.

[0086] (Sample preparation) One release PET film was peeled off from a double-sided adhesive sheet with release PET films on both sides, and a 30 μm thick stainless steel foil (SUS304) was laminated onto the resin surface and heated under pressure. The conditions were 70°C, 0.5 MPa, and 10 seconds. Next, the remaining release PET film was peeled off from the double-sided adhesive sheet, and a 30 μm thick stainless steel foil (SUS304) was laminated onto the resin surface and heated under pressure. The conditions were 120°C, 1.0 MPa, and 10 seconds. The resulting double-sided adhesive sheet with stainless steel foil laminated on both sides was then heated at 105°C for 24 hours to obtain a sample.

[0087] (Evaluation of initial normal adhesive strength) The sample was cut into a rectangle 10 mm wide and 150 mm long to obtain a measurement sample, which was left in an atmosphere of 23°C and 50% RH for 12 hours, and the adhesive strength was measured under the following conditions. (1) Measurement environment Measurements were performed in an atmosphere of 23°C and 50% RH. (2) Equipment used: Shimadzu Autograph AG-X. (3) Peeling Method The stainless steel foil was peeled off in a direction 180° to the main surface of the measurement sample. (4) Peeling speed: 30 mm / min. (5) Number of tests: Three tests were conducted. The average value of the values ​​obtained by the above method was taken as the measured value of the initial adhesive strength under normal conditions.

[0088] The initial adhesive strength under normal conditions was evaluated as follows. Excellent 20N / cm or more, Good: 10N / cm or more and less than 20N / cm Poor: Less than 10N / cm.

[0089] The initial normal adhesive strength of Example 1 measured by the above-mentioned method was 32.3 N / cm, which was excellent.

[0090] (Adhesion strength evaluation at 95°C) The sample was cut into a rectangle 10 mm wide and 150 mm long to obtain a measurement sample, which was then left in an atmosphere at 95°C for 3 minutes, and the adhesive strength was measured under the following conditions. (1) Measurement environment Measurement was performed in an atmosphere of 95°C. (2) Equipment used: Shimadzu Autograph AG-X. (3) Peeling Method The stainless steel foil was peeled off in a direction 180° to the main surface of the measurement sample. (4) Peeling speed: 30 mm / min. (5) Number of tests: Three tests were conducted. The average value of the values ​​obtained by the above method was taken as the measured value of adhesive strength in an atmosphere of 95°C.

[0091] The adhesive strength in a 95°C atmosphere was evaluated as follows. Excellent 7N / cm or more, Good: 5N / cm or more and less than 7N / cm Poor: Less than 5N / cm.

[0092] The adhesive strength of Example 1 measured by the above-mentioned method in an atmosphere of 95° C. was 10.2 N / cm, which was excellent.

[0093] (Evaluation of adhesive strength after immersion in 120°C cooling water for 1000 hours) The sample was cut into a rectangle 10 mm wide and 150 mm long, and the resulting measurement sample was immersed in a pressure-resistant container filled with cooling water maintained at 120°C for 1000 hours. The measurement sample was then removed from the pressure-resistant container, and the adhesive strength was measured under the following conditions. The cooling water used was CRUZARD (registered trademark) Straight Coolant Red, manufactured by Komeri Co., Ltd. (1) Measurement environment Measurements were performed in an atmosphere of 23°C and 50% RH. (2) Equipment used: Shimadzu Autograph AG-X. (3) Peeling Method The stainless steel foil was peeled off in a direction 180° to the main surface of the measurement sample. (4) Peeling speed: 30 mm / min. (5) Number of tests: Three tests were conducted. The average value of the values ​​obtained by the above method was taken as the measured value of adhesive strength after immersion in 120°C cooling water for 1000 hours.

[0094] The adhesive strength after immersion in 120°C cooling water for 1000 hours was evaluated as follows. Excellent 20N / cm or more, Good: 10N / cm or more and less than 20N / cm Poor: Less than 10N / cm.

[0095] The adhesive strength of Example 1 after immersion in 120° C. cooling water for 1000 hours, measured by the above-mentioned method, was 30.1 N / cm, which was excellent.

[0096] (Swelling resistance of double-sided adhesive sheet after immersion in 120°C cooling water for 1000 hours) The measurement samples used to evaluate adhesive strength after immersion in 120°C cooling water for 1000 hours were used to evaluate swelling resistance. Specifically, the measurement samples after immersion for 1000 hours were evaluated according to the following criteria. Good No swelling of the resin on the cross section of the measurement sample that comes into contact with the cooling water can be visually confirmed. Poor: Swelling of the resin on the cross section of the measurement sample that comes into contact with the cooling water can be visually confirmed.

[0097] The sample of Example 1 was visually inspected by the above-mentioned method, and no swelling was observed, resulting in a "Good" result.

[0098] (Adhesion retention rate) The adhesive strength retention rate was calculated as r = (a / b) × 100, where r is the adhesive strength retention rate (%), a is the adhesive strength (measured value) after immersion in 120°C cooling water for 1000 hours, and b is the initial adhesive strength (measured value).

[0099] The adhesive strength retention was evaluated as follows. Excellent 80% or more, Good: 50% or more but less than 80% Poor: Less than 50%.

[0100] The adhesive strength retention rate of Example 1 determined by the above method was 93.2%, which was excellent.

[0101] As described above, it was found that the double-sided adhesive sheet of Example 1 had excellent adhesive properties in a high-temperature atmosphere, and maintained excellent adhesive properties even after immersion for 1,000 hours in cooling water at 120°C, which is higher than 90°C. It was also found that the double-sided adhesive sheet of Example 1 had excellent swelling resistance and a high adhesive strength retention rate.

[0102] (Example 2) to (Example 10) and (Comparative Example 1) to (Comparative Example 6) The type and content of each component contained in the thermosetting resin composition of each Example and Comparative Example are shown in Tables 1 and 2. For the thermosetting resin compositions of Examples 2 to 10 and Comparative Examples 1 to 6, the type and content of each component were changed, but the thermosetting resin compositions were prepared in the same manner as in Example 1, and double-sided adhesive sheets were produced from them. The unit of content in the tables is "parts by mass" unless otherwise specified.

[0103] [Table 1]

[0104] [Table 2]

[0105] The equivalent weight *1 in Comparative Example 2 in Table 2 indicates the equivalent weight of carbodiimide groups per equivalent of carboxy groups in the styrene-based thermoplastic elastomer. The equivalent weight *2 in Comparative Example 3 indicates the equivalent weight of carbodiimide groups per equivalent of carboxy groups in the carboxy-containing acrylic polymer. The equivalent weight *3 in Comparative Examples 4 and 5 indicates the equivalent weight of epoxy groups per equivalent of carboxy groups in the acid-modified polyolefin.

[0106] As shown in Table 1, the double-sided adhesive sheets of Examples 2 to 10 also had excellent adhesive properties in a high-temperature atmosphere, and were found to maintain excellent adhesive properties even after immersion for 1,000 hours in cooling water at 120°C, which is higher than 90°C. Furthermore, the double-sided adhesive sheets of Examples 2 to 10 were found to have excellent swelling resistance and high adhesive strength retention.

[0107] It was also found that the adhesive sheets made from the thermosetting resin compositions of Examples 1 to 10 had excellent adhesive properties in a high-temperature atmosphere, and maintained excellent adhesive properties even after immersion for 1,000 hours in cooling water at 120°C, which is higher than 90°C. They also had excellent swelling resistance and high adhesive strength retention.

[0108] It has been found that double-sided adhesive sheets and adhesive sheets made of such thermosetting resin compositions have excellent adhesive properties even when in contact with high-temperature cooling water (coolant liquid).Furthermore, fuel cells sealed with such double-sided adhesive sheets or adhesive sheets can be used for long periods of time.

[0109] The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Furthermore, the above-described embodiments are intended to illustrate the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the scope of the meaning of the invention equivalent thereto are considered to be within the scope of the present invention.

[0110] (Addendum) Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) an acid-modified polyolefin having a melting point of 100°C or less; a polycarbodiimide having a plurality of carbodiimide groups; Particles made of resin, Thermosetting resin composition.

[0111] (Appendix 2) Attachment 1: The thermosetting resin composition according to Appendix 1, wherein the acid-modified polyolefin has a carboxy group.

[0112] (Appendix 3) 3. The thermosetting resin composition according to claim 2, wherein the polycarbodiimide contains 0.1 to 8.0 equivalents of the carbodiimide group relative to 1 equivalent of the carboxy group.

[0113] (Appendix 4) 4. The thermosetting resin composition according to any one of claims 1 to 3, wherein the acid-modified polyolefin has an acid value of 1 mgKOH / g or more and 40 mgKOH / g or less.

[0114] (Appendix 5) 5. The thermosetting resin composition according to any one of claims 1 to 4, wherein the resin is at least one resin selected from the group consisting of an acrylic resin, a styrene resin, and a urethane resin.

[0115] (Appendix 6) 6. The thermosetting resin composition according to claim 1, wherein the content of the particles is 1.0 part by mass or more and 200 parts by mass or less relative to 100 parts by mass of the acid-modified polyolefin.

[0116] (Appendix 7) An adhesive sheet comprising the thermosetting resin composition according to any one of claims 1 to 6.

[0117] (Appendix 8) Film and and adhesive layers formed on both sides of the film, 7. A double-sided adhesive sheet, wherein the adhesive layer is composed of the thermosetting resin composition according to any one of claims 1 to 6.

[0118] (Appendix 9) The double-sided adhesive sheet according to Appendix 8, wherein the film is at least one film selected from the group consisting of polyethylene films, unstretched polypropylene films, stretched polypropylene films, polyethersulfone films, polyimide films, polyamideimide films, polyethylene naphthalate films, polyether ether ketone films, and polyphenylene sulfide films.

[0119] (Appendix 10) 10. The double-sided adhesive sheet according to claim 8 or 9, wherein the thickness of the film is 12 μm or more and 200 μm or less.

[0120] (Appendix 11) an electrolyte membrane; an anode electrode laminated on one surface of the electrolyte membrane; a cathode electrode laminated on the other surface of the electrolyte membrane; a first separator that is larger than the anode electrode and is provided on the other surface of the anode electrode that is opposite to the surface on which the electrolyte membrane is laminated; a second separator provided on the other surface of the cathode electrode opposite to the surface on which the electrolyte membrane is laminated, the second separator being larger than the cathode electrode; a first inner peripheral surface, which is the peripheral edge of one surface of the first separator on which the anode electrode is laminated, facing a second inner peripheral surface, which is the peripheral edge of one surface of the second separator on which the cathode electrode is laminated, and the space between the first inner peripheral surface and the second inner peripheral surface is sealed with the adhesive sheet described in Appendix 7 or the double-sided adhesive sheet described in Appendix 8.

[0121] (Appendix 12) 12. The fuel cell according to claim 11, wherein the first separator and the second separator are made of stainless steel or titanium.

[0122] (Appendix 13) 13. The fuel cell according to claim 12, wherein the adhesive strength between the adhesive sheet according to claim 7 and the first separator or the second separator after immersion in cooling water at 120°C for 1000 hours is 10 N / cm or more.

[0123] (Appendix 14) 13. The fuel cell according to claim 12, wherein the adhesive strength between the double-sided adhesive sheet according to claim 8 and the first separator or the second separator after immersion in cooling water at 120°C for 1000 hours is 10 N / cm or more. [Explanation of symbols]

[0124] 10 solid polymer fuel cell, 30 anode electrode, 40 cathode electrode, 50 electrolyte membrane, 31 anode catalyst layer, 41 cathode catalyst layer, 32, 42 gas diffusion layer, 21, 22 separator, 23, 24, 25, 26 groove, 27, 28 inner edge surface, 60 adhesive sheet, 70 power generation cell.

Claims

1. an acid-modified polyolefin having a melting point of 100°C or less; a polycarbodiimide having a plurality of carbodiimide groups; Particles made of resin, Thermosetting resin composition.

2. The thermosetting resin composition according to claim 1 , wherein the acid-modified polyolefin has a carboxy group.

3. The thermosetting resin composition according to claim 2 , wherein the polycarbodiimide contains 0.1 equivalents or more and 8.0 equivalents or less of the carbodiimide group relative to 1 equivalent of the carboxy group.

4. The thermosetting resin composition according to claim 1 , wherein the acid-modified polyolefin has an acid value of 1 mgKOH / g or more and 40 mgKOH / g or less.

5. The thermosetting resin composition according to claim 1 , wherein the resin is at least one resin selected from the group consisting of an acrylic resin, a styrene resin, and a urethane resin.

6. The thermosetting resin composition according to claim 1 , wherein the content of the particles is 1.0 part by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the acid-modified polyolefin.

7. An adhesive sheet comprising the thermosetting resin composition according to claim 1 .

8. Film and and adhesive layers formed on both sides of the film, A double-sided adhesive sheet, wherein the adhesive layer is formed from the thermosetting resin composition according to any one of claims 1 to 6.

9. 9. The double-sided adhesive sheet according to claim 8, wherein the film is at least one film selected from the group consisting of polyethylene films, unstretched polypropylene films, stretched polypropylene films, polyethersulfone films, polyimide films, polyamideimide films, polyethylene naphthalate films, polyether ether ketone films, and polyphenylene sulfide films.

10. The double-sided adhesive sheet according to claim 8 or 9, wherein the thickness of the film is 12 μm or more and 200 μm or less.

11. an electrolyte membrane; an anode electrode laminated on one surface of the electrolyte membrane; a cathode electrode laminated on the other surface of the electrolyte membrane; a first separator that is larger than the anode electrode and is provided on the other surface of the anode electrode that is opposite to the surface on which the electrolyte membrane is laminated; a second separator provided on the other surface of the cathode electrode opposite to the surface on which the electrolyte membrane is laminated, the second separator being larger than the cathode electrode; 9. A fuel cell, wherein a first inner peripheral surface, which is the peripheral edge of one surface of the first separator on which the anode electrode is laminated, faces a second inner peripheral surface, which is the peripheral edge of one surface of the second separator on which the cathode electrode is laminated, and the space between the first inner peripheral surface and the second inner peripheral surface is sealed with the adhesive sheet according to claim 7 or the double-sided adhesive sheet according to claim 8.

12. 12. The fuel cell according to claim 11, wherein the first separator and the second separator are made of stainless steel or titanium.

13. 13. The fuel cell according to claim 12, wherein the adhesive strength between the adhesive sheet according to claim 7 and the first separator or the second separator after immersion in cooling water at 120°C for 1000 hours is 10 N / cm or more.

14. 13. The fuel cell according to claim 12, wherein the adhesive strength between the double-sided adhesive sheet according to claim 8 and the first separator or the second separator after immersion in cooling water at 120°C for 1000 hours is 10 N / cm or more.

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