Urethane urea resin, method for producing same, adhesive composition, cured product, adhesive sheet, and fuel cell member

Abstract

Provided are: a urethane urea resin having excellent heat resistance and wet heat resistance suitable for an adhesive for a solid polymer type fuel cell; a method for producing same; and an adhesive composition, a cured product, an adhesive sheet and a fuel cell member that contain said resin. A urethane urea resin according to the present disclosure contains constituent units derived from a polyol compound (A), a polyisocyanate compound (B) and an amine compound (C). At least one of components (A), (B) and (C) has an alicyclic structure. Component (A) contains a carboxyl group-containing diol compound (a1). If the total amount of components that constitute the urethane urea resin is taken to be 100 mass%, the total content of components having an alicyclic structure is 5.0-40.0 mass%. The urethane urea resin has an acid value of 5-30 mg KOH / g and a urea bond concentration of 0.20-1.00 mmol / g.

Description

Urethane urea resin and its manufacturing method, adhesive composition, cured product, adhesive sheet, and fuel cell component

[0001] The present disclosure relates to a urethane urea resin and a method for producing the same, and also to an adhesive composition, a cured product, an adhesive sheet, and a fuel cell member.

[0002] Energy and environmental issues have created a demand for clean, highly efficient power generation devices. Fuel cells, which essentially produce water as a product of electrode reactions, have attracted attention as a clean power generation system with almost no adverse impact on the global environment. In particular, polymer electrolyte fuel cells are capable of starting at relatively low temperatures and are expected to be miniaturized and have high output, so there are high hopes for their practical application.

[0003] Generally, a solid polymer electrolyte fuel cell has a solid polymer electrolyte membrane made of a polymer ion exchange membrane. A membrane electrode assembly (MEA) is used as a component, with an anode electrode on one side of the membrane and a cathode electrode on the other side. In recent years, as in Patent Documents 1 to 3, a configuration has been proposed in which a resin frame member is used around the periphery of the solid polymer electrolyte membrane in order to reduce the amount of expensive solid polymer electrolyte membrane used and support the solid polymer electrolyte membrane, which has low membrane strength. In the configuration using the resin frame member, if an adhesive is used, it is necessary to bond both the resin frame member and the solid polymer electrolyte membrane. Furthermore, because hydrogen and oxygen generate heat and generate water inside the fuel cell, the adhesive used to bond the gasket member must be able to withstand use in high-temperature, high-humidity environments.

[0004] Patent Document 1: JP 2007-066766 A Patent Document 2: JP 2017-162640 A Patent Document 3: JP 2021-180135 A

[0005] Examples of resins that can be used to form the resin frame include polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), and polyethylene terephthalate (PET). Among these examples, PPS boasts excellent heat resistance, flame retardancy, rigidity, chemical resistance, hot water resistance, and electrical insulation, resulting in superior long-term durability compared to PET and PEN. Therefore, it is expected to improve the long-term durability of fuel cells. However, PPS has poor wettability and adhesive properties, making it difficult to bond PPS to a solid polymer electrolyte membrane. Therefore, there is a need for a useful adhesive that provides good adhesion (initial adhesion) between PPS and a solid polymer electrolyte membrane, and also exhibits excellent heat- and humidity-resistant adhesive strength and heat-resistant adhesive strength even after moist heat treatment and high-temperature treatment. The properties of the adhesive depend on the physical properties of the resin used. To provide an adhesive that exhibits the aforementioned performance, a resin that does not deteriorate even under high-temperature and moist heat conditions and exhibits good adhesive properties when used as an adhesive is required. However, such a resin has not yet been developed.

[0006] The present disclosure aims to provide a urethane urea resin that is suitable for use as an adhesive for polymer electrolyte fuel cells and has excellent heat resistance and moist heat resistance, and a method for producing the same. It also aims to provide an adhesive composition, a cured product, an adhesive sheet, and a fuel cell component that exhibit good adhesion to PPS and a solid polymer electrolyte membrane and have excellent moist heat-resistant and heat-resistant adhesive strength.

[0007] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by the following embodiments, and have completed the present disclosure. [1]: A urethane urea resin containing a polyol compound (A), a polyisocyanate compound (B), and an amine compound (C) as structural units, characterized in that at least one of the polyol compound (A), the polyisocyanate compound (B), and the amine compound (C) has an alicyclic structure, the polyol compound (A) contains a diol compound (a1) having a carboxy group, the total content of the components having an alicyclic structure is 5.0 to 40.0 mass% based on 100 mass% of the total components constituting the urethane urea resin, the acid value of the urethane urea resin is 5 to 30 mgKOH / g, and the urea bond concentration in the urethane urea resin is 0.20 to 1.00 mmol / g. [2]: The urethane urea resin according to [1], wherein the polyol compound (A) further contains at least one of a dimer diol (a2) and a polycarbonate polyol (a3). [3]: The urethane urea resin according to [1] or [2], wherein the polyisocyanate compound (B) contains a polyisocyanate (b1) having an alicyclic structure. [4]: ​​The urethane urea resin according to any one of [1] to [3], wherein the amine compound (C) contains a diamine (c1) having an alicyclic structure. [5]: A method for producing the urethane urea resin according to any one of [1] to [4] in a mixed solvent containing two solvents: a solvent (S1) having a hydrogen bond term δh of Hansen's solubility parameter of 0 or more but less than 10, and a solvent (S2) having a δh of 10 to 25, wherein the proportion of the solvent (S2) in 100% by mass of the mixed solvent is 10 to 40% by mass. [6]: An adhesive composition comprising the urethane urea resin according to any one of [1] to [4] and a curing agent, wherein the curing agent contains at least one selected from the group consisting of epoxy compounds, carbodiimide compounds, oxazoline compounds, and aziridine compounds. [7]: The adhesive composition according to [6], wherein the molar ratio (Y / X) of the carboxy group (X) in the urethane urea resin to the functional group (Y) in the curing agent is 1.0 / 1.0 to 5.0 / 1.0. [8]: A cured product obtained by curing the adhesive composition according to [6] or [7].[9]: An adhesive sheet having a substrate and an adhesive layer made of the adhesive composition according to [6] or [7].

[10] : A fuel cell member made of the adhesive sheet according to [9].

[0008] The present disclosure provides an adhesive composition, a cured product, an adhesive sheet, and a fuel cell component that exhibit excellent adhesion to PPS and a solid polymer electrolyte membrane and have excellent heat resistance and moist heat resistance.

[0009] The present disclosure will be described in detail below. In the following description, "diol compound (a1) having a carboxy group," "polyisocyanate (b1) having an alicyclic structure," and "diamine (c1) having an alicyclic structure" may be abbreviated as "diol (a1)," "polyisocyanate (b1)," and "diamine (c1)," respectively. In this specification, a numerical range specified using "to" includes the numerical values ​​written before and after "to" as the lower and upper limit values ​​of the range.

[0010] The urethane urea resin of the present disclosure contains a polyol compound (A), a polyisocyanate compound (B), and an amine compound (C) as structural units. In other words, the urethane urea resin of the present disclosure is obtained by reacting at least the polyol compound (A), the polyisocyanate compound (B), and the amine compound (C) as raw materials, and contains structural units derived from each of these components. Each component constituting the urethane urea resin of the present disclosure will be described below.

[0011] <Polyol Compound (A)> The polyol compound (A) contains a diol compound (a1) having a carboxy group. The diol (a1) can be used alone or in combination of two or more. By containing the diol (a1), a crosslinking group can be introduced into the resin, and excellent heat resistance and moist heat resistance can be obtained.

[0012] Examples of the diol (a1) include dihydroxyfumaric acid, dihydroxymaleic acid, dimethylolacetic acid, glyceric acid, dimethylolpropionic acid, dimethylolpropionic acid, 2,3-dihydroxy-2-methylpropanoic acid, dimethylolbutanoic acid, 2,2-dimethylolbutanoic acid, 2,3-dihydroxybutanoic acid, 3-deoxytetronic acid, 3,4-dihydroxybutanoic acid, 2,4-dihydroxy-3,3-dimethylbutanoic acid, 2,3-dihydroxy-2-methylbutanoic acid, 2,3-dihydroxy-2-ethylbutanoic acid, 2,3-dihydroxy-2-isopropylbutanoic acid, and 2,3-dihydroxy-2-butyl aliphatic dioxycarboxylic acids such as butanoic acid, vanadium acid, tartaric acid, dimethylol valeric acid, mevalonic acid, dimethylol caproic acid, dimethylol enanthic acid, dimethylol caprylic acid, dimethylol bellargonic acid, dimethylol capric acid, dimethylol lauric acid, dimethylol myristic acid, 2,2-bis(hydroxymethyl)pentadecanoic acid, dimethylol palmitic acid, dimethylol margaric acid, dimethylol stearic acid, dimethylol oleic acid, dimethylol linoleic acid, dimethylol linolenic acid, dimethylol arachodonic acid, dimethylol docosahexaenoic acid, and dimethylol eicosapentaenoic acid; 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2,6-dihydroxy-4-methylbenzoic acid, 2,4-dihydroxy-6-methylbenzoic acid, 3,5-dihydroxy-4-methylbenzoic acid, 2,4-dihydroxy-3,6-dimethylbenzoic acid, 2,3-dihydroxy-4-methoxybenzoic acid, 3,4-dihydroxy-5-methylbenzoic acid hydroxybenzoic acid, 2,4-di(hydroxymethyl)benzoic acid, 3,4-di(hydroxymethyl)benzoic acid, 4-bromo-3,5-dihydroxybenzoic acid, 5-bromo-2,4-dihydroxybenzoic acid, 3-chloro-2,6-dihydroxybenzoic acid, 5-chloro-2,4-dihydroxybenzoic acid, hydroxy(4-hydroxy-3-methoxyphenyl)acetic acid, D,L-3,4-dihydroxymandelic acid, 2,5-dihydroxyphenylacetic acid, 3,4-dihydroxyphenylacetic acid, 3,4-(methylenedioxy)phenylacetic acid, 3-(3,4-dihydroxyphenyl)propanoic acid, 3-(2,4-dihydroxyphenyl)acrylic acid, 3-(3,4-dihydroxyphenyl)acrylic acid, 4,4'-bis(p-hydroxyphenyl)pentanoic acid, 3-(3,4-methylenedioxyphenyl)propionic acid, 2,2-bis(hydroxymethyl)butyric acid, 2,4-dihydroxycinnamic acid, 2,5-dihydroxycinnamic acid, cinnamyl-3,4-dihydroxy-α-cyanocinnamic acid, 2-bromo-4,5-methylenedioxycinnamic acid, 3,4-methylenedioxycinnamic acid, 4,5-methylenedioxy-2-nitrocinnamic acid, 2,6-dihydroxyisonicotinic acid, DL-3,4-dihydroxymandelic acid, 1,4-dihydroxy-2-naphthalenecarboxylic acid Examples of aromatic ring- or heterocyclic ring-containing dioxycarboxylic acids include 3,5-dihydroxy-2-naphthalenecarboxylic acid, 3,7-dihydroxy-2-naphthalenecarboxylic acid, 4,8-dihydroxyquinoline-2-carboxylic acid (also known as xanthurenic acid), 3-(3,4-dihydroxyphenyl)propionic acid, 2,4-dihydroxypyrimidine-5-carboxylic acid, 2,6-dihydroxypyridine-4-carboxylic acid (also known as citrazinic acid), 2,4-dihydroxythiazole-5-acetic acid, 2-(1-thienyl)ethyl-3,4-dihydroxybenzylidenecyanoacetic acid, 6-estradiol dipropionate, 2,5-dihydroxy-1,4-benzenediacetic acid, and (2R,3R)-2,3-dihydroxy-3-(phenylcarbamoyl)propionic acid. From the viewpoint of solvent solubility, dimethylolpropionic acid and dimethylolbutanoic acid are preferred.

[0013] The polyol compound (A) may further contain at least one of a dimer diol (a2) and a polycarbonate polyol (a3) ​​in addition to the diol (a1).

[0014] Dimer diol (a2) is synthesized by hydrogenating dimer acid, a dimer of unsaturated fatty acid, and is obtained as a mixture of geometric isomers of dimer diol having a branched structure or an alicyclic structure. The dimer acid is obtained by thermally polymerizing 18-carbon carboxylic acids, such as unsaturated fatty acids such as linoleic acid, oleic acid, and linolenic acid, or drying oil fatty acids or semi-drying oil fatty acids obtained from tall oil, cottonseed oil, soybean oil, etc., using a known method, followed by distillation and purification. The main component is a 36-carbon dicarboxylic acid. Known hydrogenation methods can be used to synthesize dimer diol from dimer acid. Specifically, dimer diol can be obtained by catalytic reduction according to standard methods using a hydrogenation catalyst such as Raney nickel, nickel-diatomaceous earth, or an inorganic refractory material (e.g., alumina, silica, etc.) supported with a Group 8 element such as platinum. Commercially available dimer diols used in the present disclosure include, for example, Pripol 2033 manufactured by Croda.

[0015] Examples of the polycarbonate polyol (a3) ​​include those obtained by reacting a low-molecular-weight polyol with a carbonate compound.

[0016] Examples of the low molecular weight polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, hexanediol, octanediol, nonanediol, dipropylene glycol, diethylene glycol, triethylene glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, polyoxyethylene bifunctional low molecular weight polyols such as ethylene glycol (addition mole number 10 or less), polyoxypropylene glycol (addition mole number 10 or less), cyclohexanediol, cyclohexanedimethanol, tricyclodecane dimethanol, cyclopentadiene dimethanol, dimer diol, bisphenol A, N,N-bis(2-hydroxypropyl)aniline, dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, dihydroxypropionic acid, and dihydroxybenzoic acid;Trimethylolethane, trimethylolpropane, 1,1,1-trimethylolbutane, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,6-butanetriol, trimethylolbutene, trimethylolpentene, trimethylolhexene, trimethylolheptene, trimethyloloctene, trimethylolnonene, trimethyloldecene, trimethylolundecene, trimethyloldodecene, trimethyloltridecene, trimethylolpentadecene, trimethylolhexadecene, trimetrolheptadecene, trimethylolpentadecene, trimethylolhexadecene, trimethylolheptadecene, trimethylol octadecene, 1,1,1-trimethylol-2-methyl-hexane, 1,1,1-trimethylol-3-methyl-hexane, 1,1,1-trimethylol-2-ethyl-hexane, 1,1,1-trimethylol-3-ethyl-hexane, trimethylol hexene, 1,2,3-octanetriol, 1,3,7-octanetriol, 3,7-dimethyl-1,2,3-octanetriol, 1,1,1-trimethylol decane, 1,2,10-decanetriol, 1,1,1-trimethylol isoheptadecane, 1,1,1-trimethylol 1,1,1-trimethylol-sec-butane, 1,1,1-trimethylol-tert-pentane, 1,1,1-trimethylol-tert-nonane, 1,1,1-trimethylol-tert-tridecane, 1,1,1-trimethylol-tert-heptadecane, 1,1,1-trimethylol-2-methyl-hexane, 1,1,1-trimethylol-3-methyl-hexane, 1,1,1-trimethylol-2-ethyl-hexane, 1,1,1-trimethylol-3-ethyl-hexane, 1,1,1-trimethylolisoheptadecane, 1,2,3,4-butanetetraol tri- or higher functional low molecular weight polyols such as ethanol, pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, diglycerin, triglycerin, polyglycerin, ditrimethylolethane, ditrimethylolpropane, tris(2-hydroxyethyl)isocyanurate, benzene-1,3,5-triol, benzene-1,2,3-triol, stilbene-3,4',5-triol, sucrose, inositol, sorbitan, sorbitol, mannitol, saccharose, cellulose, and xylitol;

[0017] Examples of the carbonate compound include the following compounds: dialkyl carbonates such as dimethyl carbonate or diethyl carbonate, alkylene carbonates such as ethylene carbonate, and diaryl carbonates such as diphenyl carbonate.

[0018] From the viewpoint of improving heat resistance and moist heat resistance, the polyol compound (A) preferably contains at least one of a dimer diol (a2) and a polycarbonate polyol (a3) ​​in addition to the diol (a1). The polycarbonate polyol (a3) ​​is more preferably a polycarbonate polyol having an alicyclic structure. The polycarbonate polyol having an alicyclic structure is not particularly limited as long as it has an alicyclic structure having 6 or more carbon atoms in the molecule, and for example, those described in Japanese Patent No. 5303846 can also be used.

[0019] The polyol compound (A) may contain a polyol other than the carboxyl group-containing diol (a1), dimer diol (a2), and polycarbonate polyol (a3) ​​for the purpose of controlling adhesiveness and durability, etc. Examples of the other polyol that can be used include the low-molecular-weight polyols described in the description of the polycarbonate polyol (a3), as well as polyether polyols, polyester polyols, polyolefin polyols, vegetable oil-based polyols other than dimer diols, which are generally known as polyols constituting polyurethane resins, and mixtures thereof.

[0020] Examples of polyether polyols include polymers or copolymers of methylene oxide, ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, etc., such as glycols such as polyethylene glycol, polypropylene glycol, poly(ethylene / propylene) glycol, and polytetramethylene glycol; condensates of hexanediol, methylhexanediol, heptanediol, octanediol, or mixtures thereof; and polyols obtained by adding alkylene oxides such as methylene oxide, ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, or polyoxytetramethylene oxide to a compound having two or more active hydrogen groups.

[0021] Examples of polyester polyols include polyester polyols obtained by condensation reaction of the above-mentioned low-molecular-weight polyols with a dibasic acid component. Examples of dibasic acid components include aliphatic or aromatic dibasic acids such as terephthalic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, hydrogenated dimer acid, phthalic anhydride, isophthalic acid, trimellitic acid, glutaric acid, pimelic acid, suberic acid, and sebacic acid, as well as anhydrides thereof. Furthermore, polyester polyols obtained by ring-opening polymerization of cyclic ester compounds of lactones such as ε-caprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone may also be used.

[0022] Examples of polyolefin polyols include hydroxyl group-containing polybutadiene, hydrogenated hydroxyl group-containing polybutadiene, hydroxyl group-containing polyisoprene, hydrogenated hydroxyl group-containing polyisoprene, hydroxyl group-containing chlorinated polypropylene, and hydroxyl group-containing chlorinated polyethylene.

[0023] Examples of vegetable oil-based polyols other than dimer diol include polyols made from plant-derived castor oil or soybean oil.

[0024] <Polyisocyanate Compound (B)> The polyisocyanate compound (B) is not particularly limited as long as it is a compound containing two or more isocyanate groups in one molecule. In the present disclosure, the polyisocyanate compound (B) is broadly classified into polyisocyanates (b1) having an alicyclic structure and polyisocyanates not having an alicyclic structure. The polyisocyanate compound (B) can be used alone or in combination of two or more types.

[0025] Examples of the polyisocyanate (b1) include isophorone diisocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (4,4'-methylenebis(cyclohexyl isocyanate), HMDI), 1,4-bis(isocyanatomethyl)cyclohexane, hydrogenated xylylene diisocyanate, dimer acid diisocyanate, and norbornene diisocyanate. Of the above, from the viewpoint of moist heat resistance, IPDI and HMDI are preferred as the polyisocyanate (b1), and IPDI is more preferred.

[0026] Examples of polyisocyanates not having an alicyclic structure include aliphatic polyisocyanates not having an alicyclic structure, such as butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate; and aromatic polyisocyanates not having an alicyclic structure, such as 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-benzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, and xylylene diisocyanate.

[0027] The polyisocyanate compound (B) preferably contains a polyisocyanate (b1) having an alicyclic structure, which improves the wet heat resistance.

[0028] <Amine Compound (C)> The amine compound (C) can be appropriately selected from known compounds. It preferably contains a diamine (c1) having an alicyclic structure, and may contain amines other than the diamine (c1). Each of these can be used alone or in combination of two or more. By containing the diamine (c1), moist heat resistance is improved.

[0029] Examples of the diamine (c1) having an alicyclic structure include alicyclic diamines such as isophoronediamine (IPDA), norbornanediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,4-bis(aminomethyl)cyclohexane, 4,4′-methylenebis(cyclohexylamine), piperazine, and dimer diamine.

[0030] Dimer diamine is a dimer acid in which the two terminal carboxyl groups (-COOH) of the dimer acid are replaced by aminomethyl groups (-CH ２ -NH ２ ) or amino group (-NH ２) is an alicyclic diamine compound obtained by substituting . Dimer acid is a known compound obtained by dimerizing unsaturated fatty acids (preferably those having 11 to 22 carbon atoms, particularly preferably those having 18 carbon atoms), and its industrial production process is largely standardized in the industry. Dimer acids whose main component is a 36-carbon dimer acid obtained by dimerizing an 18-carbon unsaturated fatty acid, such as oleic acid or linoleic acid, are particularly useful because they are inexpensive and readily available. Furthermore, dimer acids may contain any amount of monomer acid, trimer acid, other polymerized fatty acids, etc., depending on the production method, degree of purification, etc. Furthermore, although double bonds remain after the polymerization reaction (dimerization reaction) of unsaturated fatty acids, in the present disclosure, hydrogenated products obtained by further hydrogenation to reduce the degree of unsaturation are also included in the term dimer acid. Commercially available products of dimer diamine (c1) include, for example, "Priamine 1071," "Priamine 1073," "Priamine 1074," and "Priamine 1075" manufactured by Croda Japan Co., Ltd., and "Versamine 551" and "Versamine 552" manufactured by Cognis Japan Co., Ltd.

[0031] Of the above, from the viewpoint of moist heat resistance, IPDA, dimer diamine, 1,4-bis(aminomethyl)cyclohexane, and 4,4'-methylenebis(cyclohexylamine) are preferred as diamine (c1), and IPDA and dimer diamine are more preferred.

[0032] Other examples of the amine compound include aliphatic diamines having no alicyclic structure, aromatic diamines, diaminopolysiloxanes, polyoxyalkylene polyamines, aliphatic monoamines, and aromatic monoamines.

[0033] Examples of aliphatic diamines not having an alicyclic structure include ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,9-nonanediamine, 1,12-dodecamethylenediamine, metaxylenediamine, 2-(2-aminoethylamino)ethanol, N-(2-hydroxyethyl)-1,3-propanediamine, (2-hydroxyethylpropylene)diamine, N,N'-bis(2-hydroxyethyl)ethylenediamine, (di-2-hydroxyethylpropylene)diamine, (2-hydroxypropylethylene)diamine, and (di-2-hydroxypropylethylene)diamine.

[0034] Examples of aromatic diamines include 1,4-diaminobenzene, 1,3-diaminobenzene, 1,2-diaminobenzene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, 2,6-diaminotoluene, 2,4-diaminotoluene, 3,4-diaminotoluene, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diamino-1,2-diphenylethane, 3, Examples of the diaminodiphenylmethane include 3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 3,3'-diaminodiphenylsulfone, bisanilinefluorene, 4,4'-isopropylidenebis(2-aminophenol), 4,4'-(hexafluoroisopropylidene)bis(2-aminophenol), and 5,5'-methylenebis(2-aminobenzoic acid).

[0035] Examples of diaminopolysiloxanes include α,ω-bis(2-aminoethyl)polydimethylsiloxane, α,ω-bis(3-aminopropyl)polydimethylsiloxane, α,ω-bis(4-aminobutyl)polydimethylsiloxane, α,ω-bis(5-aminopentyl)polydimethylsiloxane, α,ω-bis[3-(2-aminophenyl)propyl]polydimethylsiloxane, α,ω-bis[3-(4-aminophenyl)propyl]polydimethylsiloxane, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 1,3-bis(4-aminobutyl)tetramethyldisiloxane, etc. Commercially available diaminopolysiloxanes include KF-8010, X-22-161A, and X-22-161B (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0036] Examples of polyoxyalkylene polyamines include polyoxypropylene diamine, trimethylolpropane poly(oxypropylene) triamine, glyceryl poly(oxypropylene) triamine, polyoxyethylene diamine, trimethylolpropane poly(oxyethylene) triamine, glyceryl poly(oxyethylene) triamine, etc. Commercially available polyoxyalkylene polyamines include JEFFAMINE D-230, JEFFAMINE D-400, JEFFAMINE D-2000, and JEFFAMINE D-4000 (all manufactured by HUNTSMAN).

[0037] Examples of the aliphatic monoamine include n-butylamine, di-n-butylamine, n-propylamine, n-pentylamine, n-hexylamine, n-octylamine, cyclohexylamine, N-methylcyclohexylamine, monoethanolamine, and diethanolamine.

[0038] Examples of aromatic monoamines include aniline, 1-naphthylamine, 2-naphthylamine, 1-aminoanthracene, 2-aminoanthracene, 9-aminoanthracene, 9-aminophenanthracene, 2-aminobiphenyl, 3-aminobiphenyl, 4-aminobiphenyl, 2-aminophenol, 3-aminophenol, 4-hydroxybenzylamine, 2-hydroxybenzylamine, 4-aminophenol, 2-mercaptoaniline, 3-mercaptoaniline, and 4-mercaptoaniline.

[0039] <Urethane urea resin> In the urethane urea resin of the present disclosure, at least one of the polyol compound (A), polyisocyanate compound (B), and amine compound (C) used as polymerization raw materials has an alicyclic structure. The polyol compound (A) contains a diol compound (a1) having a carboxy group. The content of components having an alicyclic structure is 5.0 to 40.0 mass% out of a total of 100 mass% of the components constituting the urethane urea resin. In other words, in each raw material component constituting the urethane urea resin, the total content of masses derived from alicyclic structures, calculated based on the mass proportion of the alicyclic structures, is 5.0 to 40.0 mass% of the entire urethane urea resin. By having this content of 5.0 to 40.0 mass%, good moist heat resistance and heat resistance can be obtained.

[0040] The alicyclic content indicates the mass percentage of the moiety (alicyclic hydrocarbon residue) obtained by removing two hydrogen atoms from an alicyclic hydrocarbon. For example, if the alicyclic structure is a cyclohexane ring, the moiety (cyclohexane residue) obtained by removing two hydrogen atoms from cyclohexane is present in each material. The content of components having an alicyclic structure in a urethane urea resin indicates the mass percentage of alicyclic hydrocarbon residues present in the polyurethane resin. Specifically, if the urethane urea resin is composed of 20 parts of a compound with an alicyclic content of 49.5%, 60 parts of a compound with an alicyclic content of 0%, and 20 parts of a compound with an alicyclic content of 46.4%, the total content of components having an alicyclic structure in the urethane urea resin is calculated as 49.5 x 0.2 + 0 x 0.6 + 46.4 x 0.2 = 19.2 mass%.

[0041] The total content of components having an alicyclic structure in the urethane urea resin is more preferably 10.0 to 30.0% by mass, and even more preferably 10.0 to 25.0% by mass.

[0042] The urethane urea resin of the present disclosure has an acid value of 5 to 30 mgKOH / g. The urethane urea resin of the present disclosure also has a urea bond concentration of 0.20 to 1.00 mmol / g. When the acid value is 5 to 30 mgKOH / g, good heat resistance is obtained. When the urethane urea resin has a urea bond concentration of 0.20 to 1.00 mmol / g, adhesion to substrates is improved.

[0043] The acid value of the urethane urea resin is preferably 5 to 15 mgKOH / g. The method for measuring the acid value will be described in detail in the Examples.

[0044] The urea bond concentration in the urethane urea resin is preferably 0.20 to 0.80 mmol / g, more preferably 0.40 to 0.80 mmol / g.

[0045] The urea bond concentration is a value represented by the following formula. When a prepolymer having terminal isocyanate groups is synthesized under the condition of (NCO molar equivalents / OH molar equivalents) > 1, and then chain-extended with polyamine to form a polyurethane resin having amino groups at its terminals, the urea bond concentration is represented by the following formula (1): Formula (1): Urea bond concentration (mmol / g) = [total number of moles of isocyanate groups (mmol) - total number of moles of hydroxyl groups (mmol)] / total solid content (g) When a prepolymer having terminal isocyanate groups is synthesized under the condition of (NCO molar equivalents / OH molar equivalents) > 1, and then chain-extended with polyamine to form a polyurethane resin having isocyanate groups at its terminals, the urea bond concentration is represented by the following formula (2): Formula (2): Urea bond concentration (mmol / g) = (total number of moles of amino groups (mmol)) / total solid content (g) Here, the total number of moles of amino groups refers to the total number of moles of amino groups in the amine compound used to react with the prepolymer having terminal isocyanate groups to form urea bonds.

[0046] The weight-average molecular weight of the urethane urea resin is preferably 90,000 to 190,000, and more preferably 100,000 to 150,000. When the weight-average molecular weight is 90,000 to 190,000, good moist heat resistance and heat resistance can be obtained. The weight-average molecular weight is a weight-average molecular weight calculated in terms of polystyrene, determined by gel permeation chromatography (GPC).

[0047] <<Method for Producing Urethane Urea Resin>> The urethane urea resin of the present disclosure can be produced by a general synthesis method. A general synthesis method for a urethane urea resin is described below. First, a polyol compound (A) and a polyisocyanate compound (B) are subjected to a urethane reaction in a reaction vessel together with a reaction solvent. A urethane prepolymer having an isocyanate group at the polymer terminal is synthesized by blending the polyisocyanate compound (B) so that the total number of moles of isocyanate groups contained in the polyisocyanate compound (B) is 1.1 to 2 equivalents of the total number of moles of hydroxyl groups in the entire polyol compound (A). The reaction is preferably carried out at 60 to 120°C until all hydroxyl groups are consumed. Next, the urethane prepolymer and an amine compound (C) are subjected to a urea-forming reaction. The amine compound (C) is preferably blended in an amount such that the total number of moles of amino groups in the amine compound (C) is 0.9 to 1 equivalent of the total number of moles of isocyanate groups in the urethane prepolymer, and the reaction is preferably carried out at 40 to 100°C until all amino groups are consumed.

[0048] A reaction catalyst can be used as needed to promote the urethanization reaction and the urea-forming reaction. Examples of the reaction catalyst include metal catalysts such as tin, bismuth, zinc, aluminum, and titanium, and amine catalysts. Tin-based catalysts are the most common metal catalysts, and examples of usable catalysts include dibutyltin dilaurate, dioctyltin dilaurate, and octic tin. Examples of usable amine catalysts include triethylamine and N,N-dimethylbenzylamine.

[0049] In the synthesis of the urethane prepolymer, it is preferable not to use a solvent having active hydrogen, such as an alcohol-based solvent. Preferred solvents include, for example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aromatic hydrocarbons such as benzene, toluene, xylene, and tetramethylbenzene; glycol ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether; esters such as ethyl acetate, butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, dialkyl glutarate, dialkyl succinate, and dialkyl adipate; It is preferable to use cyclic esters such as γ-butyrolactone; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha.

[0050] On the other hand, during the urea reaction, which is the reaction between the urethane prepolymer and the amine compound (C), it is preferable to use an alcoholic solvent in addition to the above solvent. The reason for this is that the reaction between an isocyanate group and an amino group is much more rapid than the reaction between an isocyanate group and a hydroxyl group, and therefore does not hinder the urea reaction. Examples of alcoholic solvents that can be used include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutanol, t-butanol, n-pentanol, n-hexanol, n-octanol, 2-ethylhexyl alcohol, and 1-methoxy-2-propanol.

[0051] The Hansen Solubility Parameter (HSP) of the solvents in this disclosure will be described. The Hansen Solubility Parameter is a solubility parameter introduced by Hildebrand, divided into three components: a dispersion term δd, a polar term δp, and a hydrogen bonding term δh, and expressed in three-dimensional space. In this disclosure, however, the hydrogen bonding term δh is used. These three components, the dispersion term δd, the polar term δp, and the hydrogen bonding term δh, have been extensively studied by Hansen and his successors, and are described in detail in POLYMER Handbook (fourth edition), VII-698 to 711. Furthermore, the values ​​of the Hansen Solubility Parameter for many solvents have been investigated, and are described, for example, in Wesley L. Archer's Industrial Solvents Handbook.

[0052] In producing the urethane urea resin of the present disclosure, it is preferable to carry out the reaction in a mixed solvent containing two solvents: a solvent (S1) having a hydrogen bond term δh of Hansen's solubility parameter of 0 or more and less than 10, and a solvent (S2) having a δh of 10 to 25, and it is preferable that the proportion of solvent (S2) in 100 mass% of the mixed solvent is 10 to 40 mass%. By containing the above two solvents and keeping the proportions within the above ranges, the urethane urea resin of the present disclosure can be produced stably.

[0053] Adhesive Composition The adhesive composition of the present disclosure contains the urethane urea resin (main agent) of the present disclosure and a curing agent.

[0054] <Curing Agent> The curing agent is not particularly limited as long as it reacts with the urethane urea resin of the present disclosure to produce a cured product, but is preferably a compound having multiple functional groups capable of reacting with the carboxy groups in the urethane urea resin of the present disclosure. Examples include polyisocyanate compounds, epoxy compounds, carbodiimide compounds, oxazoline compounds, aziridine compounds, and metal chelate compounds. It is preferable to contain at least one selected from the group consisting of epoxy compounds, carbodiimide compounds, oxazoline compounds, and aziridine compounds, and from the viewpoint of adhesiveness, it is more preferable to use an epoxy compound. One type of curing agent may be used alone, or two or more types may be used in combination.

[0055] The epoxy compound is not particularly limited as long as it has an epoxy group in the molecule. However, as the epoxy compound, one having an average of two or more epoxy groups per molecule is preferably used. For example, epoxy compounds such as glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, glycidyl ester type epoxy resins, and cyclic aliphatic (alicyclic) epoxy resins can be used.

[0056] Examples of glycidyl ether type epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD ​​type epoxy resins, cresol novolac type epoxy resins, phenol novolac type epoxy resins, α-naphthol novolac type epoxy resins, bisphenol A type novolac type epoxy resins, dicyclopentadiene type epoxy resins, tetrabromobisphenol A type epoxy resins, brominated phenol novolac type epoxy resins, tris(glycidyloxyphenyl)methane, and tetrakis(glycidyloxyphenyl)ethane.

[0057] Examples of the glycidylamine type epoxy resin include tetraglycidyldiaminodiphenylmethane, triglycidyl paraaminophenol, triglycidyl meta-aminophenol, and tetraglycidyl meta-xylylenediamine.

[0058] Examples of glycidyl ester type epoxy resins include diglycidyl phthalate, diglycidyl hexahydrophthalate, and diglycidyl tetrahydrophthalate.

[0059] Examples of cyclic aliphatic (alicyclic) epoxy resins include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl)adipate.

[0060] As the epoxy compound, one of these compounds can be used alone or two or more of them can be used in combination. From the viewpoint of durability, it is preferable to use bisphenol A type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, tris(glycidyloxyphenyl)methane, or tetrakis(glycidyloxyphenyl)ethane.

[0061] The carbodiimide compound is not particularly limited as long as it has two or more carbodiimide groups in the molecule. Examples of carbodiimide compounds include Carbodilite V-01, V-03, V-05, V-07, and V-09 (Nisshinbo Chemical Inc.), and cyclic carbodiimide (Teijin Limited). From the viewpoint of heat resistance, compounds having an average of three or more carbodiimide groups in one molecule are preferred.

[0062] As the oxazoline compound, a compound having two or more oxazoline groups in the molecule is preferably used. Specific examples thereof include 2'-methylenebis(2-oxazoline), 2,2'-ethenebis(2-oxazoline), 2,2'-ethenebis(4-methyl-2-oxazoline), 2,2'-propenebis(2-oxazoline), 2,2'-tetramethylenebis(2-oxazoline), 2,2'-hexamethylenebis(2-oxazoline), 2,2'-octamethylenebis(2-oxazoline), 2,2'-p-phenylenebis(2-oxazoline), 2,2'-p-phenylenebis(4,4'-dimethyl-2-oxazoline), 2,2'-p-phenylenebis(4-methyl-2-oxazoline), and 2,2'-p-phenylenebis(4-phenyl-2-oxazoline). Alternatively, it may be a copolymer of a vinyl monomer such as 2-isopropenyl-2-oxazoline or 2-isopropenyl-4,4-dimethyl-2-oxazoline with another monomer copolymerizable with the vinyl monomer. Examples of such oxazoline group-containing copolymers include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

[0063] Examples of the aziridine compound include trimethylolpropane tris[3-(aziridin-1-yl)propionate], N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), tris-2,4,6-(1-aziridinyl)-1,3,5-triazine, and 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane.

[0064] From the viewpoint of adhesiveness, the molar ratio (Y / X) of the carboxyl group (X) in the urethane urea resin to the functional group (Y) in the curing agent is preferably 1.0 / 1.0 to 5.0 / 1.0, and more preferably 1.0 / 1.0 to 3.0 / 1.0.

[0065] <Other Components> The adhesive composition of the present disclosure may contain other components such as known additives, such as plasticizers, dispersants, thickeners, antifoaming agents, and leveling agents.

[0066] <<Cured Product>> The cured product of the present disclosure refers to a product obtained by curing the adhesive composition.

[0067] The curing method is not particularly limited, but for example, the composition can be cured by drying the solvent using known drying equipment and then heating. The temperature is preferably 40°C to 170°C, more preferably 60°C to 150°C. The higher the curing temperature, the shorter the curing time can be, but the curing temperature can be adjusted as desired from the viewpoint of the heat resistance of the substrate. When curing at 80°C, the curing time is preferably 3 to 7 days. When curing at 150°C, the curing time is preferably 30 minutes to 2 hours.

[0068] <<Adhesive Sheet>> The adhesive sheet of the present disclosure has a substrate and an adhesive layer made of the adhesive composition described above. The adhesive layer may be uncured or cured.

[0069] The method for producing the adhesive sheet is not particularly limited. For example, the adhesive sheet can be coated onto the substrate using a known method such as gravure coater coating, die coater coating, comber coater coating, lip coater coating, slit coater coating, roll coater coating, spray coating, spin coater coating, or electrostatic coating.

[0070] The substrate is not particularly limited as long as it is a type of resin that can be used to form a resin frame member, and examples thereof include PPS, PPA (polyphthalamide), PEN, PES (polyethersulfone), LCP (liquid crystal polymer), PVDF (polyvinylidene fluoride), silicone resin, fluororesin, m-PPE (modified polyphenylene ether resin), PET, PBT (polybutylene terephthalate), and modified polyolefin, with PET, PEN, and PPS being preferred.

[0071] <<Fuel Cell Components>> The adhesive sheet of the present disclosure adheres well to PPS and a solid polymer electrolyte membrane and has excellent moist heat resistance and heat resistance, making it suitable for use as a fuel cell component. The fuel cell component of the present disclosure refers to a component manufactured using the adhesive sheet of the present disclosure. Specifically, the fuel cell component is a resin frame component used to support an MEA, in which either the adhesive sheet of the present disclosure applied to an electrically insulating and airtight plastic film such as PPS or PEN, or a sheet obtained by curing the adhesive sheet, is bonded and fixed to the MEA by heat lamination, heat pressing, heat curing, or other processes, either alone or in combination.

[0072] The present disclosure will be explained in more detail below using examples, but the present disclosure is not limited to these. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass". The blending amounts in the tables are parts by mass, and values ​​other than the solvent are converted into non-volatile contents. Blank spaces in the tables indicate that no blending was performed. The weight average molecular weight (Mw) and acid value of the urethane urea resin were measured using the following methods.

[0073] [Weight-average molecular weight (Mw)] The weight-average molecular weight (Mw) is a polystyrene-equivalent value determined by GPC (gel permeation chromatography). The measurement conditions are as follows: Apparatus: Shodex GPC System-21 (Showa Denko K.K.); Column: A series-connected column consisting of one Shodex KF-802 (Showa Denko K.K.), one Shodex KF-803L (Showa Denko K.K.), and one Shodex KF-805L (Showa Denko K.K.); Solvent: Tetrahydrofuran; Flow rate: 1.0 mL / min; Temperature: 40°C; Sample concentration: 0.2%; Sample injection volume: 100 μL.

[0074] [Acid Value] Approximately 0.5 g of sample dried under reduced pressure at 100°C was precisely weighed into a stoppered Erlenmeyer flask and dissolved in 100 mL of tetrahydrofuran. Phenolphthalein test solution was added as an indicator and the mixture was allowed to stand for 30 seconds. The solution was then titrated with 0.1 N alcoholic potassium hydroxide solution until it turned a pale pink color. The acid value was calculated using the following formula. The acid value was the value for the resin in its dry state (unit: mg KOH / g). Acid value (mg KOH / g) = {(5.611 x a x F) / S} / (non-volatile content concentration / 100) where S is the amount of sample collected (g), a is the amount of 0.1 N alcoholic potassium hydroxide solution consumed (mL), and F is the titer of the 0.1 N alcoholic potassium hydroxide solution.

[0075] Abbreviations used in this specification are as follows: [Polyol compound (A)] [Diol compound (a1) having a carboxy group] DMBA: dimethylol butanoic acid DMPA: dimethylol propionic acid [Dimer diol (a2)] P-2033: Dimer diol manufactured by Croda Japan Co., Ltd., trade name "PRIPOL (registered trademark) 2033" [Polycarbonate polyol (a3)] UM-90 (1 / 3): Polycarbonate diol manufactured by UBE Corporation, trade name "ETERNACOLL (registered trademark) UM-90 (1 / 3)" UM-90 (3 / 1): Polycarbonate diol manufactured by UBE Corporation, trade name "ETERNACOLL (registered trademark) UM-90 (3 / 1)" UC-100: Polycarbonate diol manufactured by UBE Corporation, trade name "ETERNACOLL (registered trademark) UC-100" CD210: Polycarbonate diol manufactured by Daicel Corporation, "PLACCEL (registered trademark) CD210" T-5651: Polycarbonate diol manufactured by Asahi Kasei Corporation, trade name "DURANOL (registered trademark) T5651" [Other polyols] CHDM: 1,4-cyclohexanedimethanol

[0076] [Polyisocyanate compound (B)] [Polyisocyanate (b1) having an alicyclic structure] IPDI: isophorone diisocyanate HMDI: 4,4'-dicyclohexylmethane diisocyanate [Other polyisocyanates] HDI: hexamethylene diisocyanate

[0077] [Amine compounds (C)] IPDA: isophoronediamine P-1075: dimer diamine manufactured by Croda Japan Co., Ltd., trade name "PRIAMINE (registered trademark) 2033" CHDA: 1,4-bis(aminomethyl)cyclohexane MBCA: 4,4'-methylenebis(cyclohexylamine) [Other amine compounds] D400: polyether diamine, trade name "JEFFAMINE (registered trademark) D-400" DBA: di-n-butylamine

[0078] [Solvents (S1) in which the hydrogen bond term δh of Hansen's solubility parameters is 0 or more and less than 10] TOL: toluene MEK: methyl ethyl ketone PGMAc: propylene glycol monomethyl ether acetate [Solvents (S2) in which the hydrogen bond term δh of Hansen's solubility parameters is 10 to 25] IPA: isopropyl alcohol PM: propylene glycol monomethyl ether

[0079] [Curing agents] G-1: Epoxy compound manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 200 g / eq, trade name "jER (registered trademark) 1031S" G-2: Epoxy compound manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 187 g / eq, trade name "jER (registered trademark) 828" G-3: Epoxy compound manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 174 g / eq, trade name "jER (registered trademark) 152" G-4: Epoxy compound manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 94 g / eq, trade name "jER (registered trademark) 630" G-5: Polycarbodiimide compound manufactured by Nisshinbo Chemical Inc., carbodiimide equivalent weight 216 g / eq, trade name "Carbodilite (registered trademark) V-03" G-6: Polycarbodiimide compound, carbodiimide equivalent 260 g / eq, trade name "Carbodilite (registered trademark) V-05" manufactured by Nisshinbo Chemical Inc. G-7: 2,2'-(1,3-phenylene)bis(2-oxazoline) G-8: Polyfunctional aziridine compound, 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate], trade name "ChemiTite (registered trademark) PZ-33" manufactured by Nippon Shokubai Co., Ltd.

[0080] [Example 1] Urethane urea resin (D-1) solution A reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube was charged with 4.0 parts of DMBA as a diol compound (a1) having a carboxy group, 100.0 parts of UM-90 (1 / 3) as a polycarbonate polyol (a3), 40.4 parts of IPDI as a polyisocyanate (b1) having an alicyclic structure, and 77.8 parts of TOL as a solvent, and reacted for 8 hours at 80 ° C. under a nitrogen atmosphere. To this, 98.8 parts of TOL was added to obtain a solution of a urethane prepolymer having an isocyanate group at the end. Next, while maintaining the obtained prepolymer solution at 70 ° C., 6.8 parts of IPDA as a diamine (c1) having an alicyclic structure, 0.33 parts of DBA as other amine compounds, 45.5 parts of IPA as a solvent, and a solution of 232.7 parts of TOL was added dropwise over 2 hours. After the dropwise addition, the mixture was allowed to react for an additional 8 hours at 70° C., yielding a urethane urea resin (D-1) solution having an acid value of 10 mgKOH / g, a weight average molecular weight of 130,000, and a solids content of 25%.

[0081] [Examples 2 to 25, Comparative Examples 1 to 6] Urethane urea resin (D-2 to 25, H-1 to 6) solutions

[0113] The same procedure as in Example 1 was carried out except that the formulations were changed to those shown in Tables 1 to 3, to obtain urethane urea resin (D-2 to 25) solutions and comparative resins (H-1 to 6).

[0082] [Comparative Example 7] A reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube was charged with 4.7 parts of DMBA as a diol compound (a1) having a carboxy group, 100.0 parts of P-2033 as a dimer diol (a2), 62.5 parts of IPDI as a polyisocyanate (b1) having an alicyclic structure, and 90.0 parts of TOL as a solvent, and reacted for 8 hours at 80 ° C. under a nitrogen atmosphere. To this, 114.3 parts of TOL was added to obtain a solution of a urethane prepolymer having an isocyanate group at the end. Next, while maintaining the obtained prepolymer solution at 70 ° C., 10.1 parts of IPDA as a diamine (c1) having an alicyclic structure, 1.17 parts of DBA as other amine compounds, and 331.0 parts of TOL as a solvent were mixed, and this solution was added dropwise over 2 hours. After completion of the dropwise addition, the reaction was continued for another 8 hours at 70°C, but precipitation occurred and the desired resin could not be produced. [Comparative Example 8] A reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube was charged with 4.0 parts of DMBA as the diol compound (a1) having a carboxy group, 100.0 parts of UM-90 (1 / 3) as the polycarbonate polyol (a3), 40.4 parts of IPDI as the polyisocyanate (b1) having an alicyclic structure, and 77.8 parts of TOL as a solvent, and the mixture was reacted for 8 hours at 80°C under a nitrogen atmosphere. 98.8 parts of TOL was added to this mixture to obtain a solution of a urethane prepolymer having an isocyanate group at the end. Next, a solution containing 6.8 parts of IPDA as the diamine (c1) having an alicyclic structure, 0.33 parts of DBA as another amine compound, and 51.0 parts of TOL and 227.1 parts of IPA as a solvent was added dropwise over 2 hours to the obtained prepolymer solution while maintaining the temperature at 70° C. After the dropwise addition, the reaction was continued for a further 8 hours at 70° C., but precipitation occurred and the desired resin could not be produced.

[0083] Details of the obtained urethane urea resins of the present disclosure (D-1 to 25) and comparative resins (H-1 to 8) are shown in Tables 1 to 4.

[0084]

[0085]

[0086]

[0087] <Evaluation of Urethane Urea Resins> The urethane urea resins of the present disclosure (D-1 to 25) and comparative resins (H-1 to 8) were evaluated by the following methods, and the results are shown in Tables 1 to 4.

[0088] [Heat Resistance] The obtained urethane urea resin was coated onto an aluminum plate so that the coating thickness after drying was 50 μm, and the plate was dried in an electric oven at 80°C for 3 minutes to obtain a urethane urea resin-coated plate. The coated plate was heated in an electric oven at 120°C for 72 hours. The weight average molecular weight (Mw) of the resin scraped off from the coated plate was measured before and after heating, and the molecular weight reduction rate after heating compared to before heating was calculated. Based on this molecular weight reduction rate, the heat resistance of the resin was evaluated according to the following criteria: +++ (very excellent): less than 5%. ++ (excellent): 5% to less than 10%. + (lower limit of practical use): 10% to less than 20%. NG (target not achieved): 20% or more.

[0089] [Moist Heat Resistance] The obtained urethane urea resin was coated onto an aluminum plate so that the coating thickness after drying was 50 μm, and then dried in an electric oven at 80°C for 3 minutes to obtain a urethane urea resin-coated plate. The coated plate was then kept in a thermo-hygrostat at 85°C and 85% relative humidity (85% RH) for 7 days. The weight average molecular weight (Mw) of the resin scraped off the coated plate before and after the storage was measured, and the molecular weight reduction rate after storage in the thermo-hygrostat was calculated. Based on this molecular weight reduction rate, the moist heat resistance was evaluated according to the following criteria: +++ (very excellent): less than 5%. ++ (excellent): 5% or more but less than 10%. + (lower practical limit): 10% or more but less than 20%. NG (target not achieved): 20% or more.

[0090]

[0091] <Production of adhesive composition> [Example 26] 100.0 parts of urethane urea resin (D-1) solution as a base agent and 0.98 parts of curing agent (G-1) as a curing agent were added and mixed with stirring at 25°C to obtain an adhesive composition.

[0092] [Examples 27 to 74, Comparative Examples 9 to 16] The same procedure as in Example 1 was carried out except that the blending compositions were changed as shown in Tables 5 to 9, to obtain adhesive compositions of Examples 27 to 74 and Comparative Examples 9 to 16.

[0093] <Evaluation of Adhesive Composition> The adhesive composition obtained was subjected to the following evaluations. The results are shown in Tables 5 to 9.

[0094] [Initial Adhesive Strength] An adhesive sheet was prepared by coating a 50 μm thick PET film, PEN film, or PPS film with an adhesive composition to a dry film thickness of 15 μm and drying at 80°C for 3 minutes. The prepared adhesive sheet was laminated with the same film as the coated substrate at 120°C, followed by heat treatment for 60 minutes in an electric oven at 150°C. The resulting "substrate / thermosetting adhesive composition / substrate" structure was used as the evaluation structure. This evaluation structure was cut into a width of 10 mm and subjected to a T-peel test at a pulling rate of 50 mm / min in an atmosphere of 23°C and 50% RH. The adhesive strength was evaluated according to the following evaluation criteria: +++ (very excellent): substrate destruction; ++ (excellent): 3 N / cm or more; + (lower practical limit): 1 N / cm or more but less than 3 N / cm; NG (target not achieved): less than 1 N / cm.

[0095] [Adhesive Strength After Durability Test] The adhesive strength of the 10 mm wide evaluation structure consisting of the "PPS / thermally cured adhesive composition / PPS" obtained above was measured after the moist heat resistance test and the heat resistance test.

[0096] (Adhesive Strength After Moisture and Heat Resistance Test) A 10 mm wide evaluation structure consisting of "PPS / thermocured adhesive composition / PPS" obtained above was subjected to a pressure cooker test (PCT) treatment [121°C, 100% RH, 168 hours]. After leaving the structure for 24 hours in an atmosphere of 23°C and 50% RH, a T-peel test was performed in an atmosphere of 23°C and 50% RH at a pulling rate of 50 mm / min, and the adhesive strength was evaluated according to the following evaluation criteria: +++ (very excellent): substrate destruction; ++ (excellent): 3 N / cm or more; + (lower practical limit): 1 N / cm or more but less than 3 N / cm; NG (target not achieved): less than 1 N / cm.

[0097] (Adhesive Strength After Heat Resistance Test) A 10 mm wide evaluation structure consisting of "PPS / thermocured adhesive composition / PPS" obtained above was treated in an electric oven at 150°C for 168 hours. After leaving it to stand for 24 hours in an atmosphere of 23°C and 50% RH, a T-peel test was performed in an atmosphere of 23°C and 50% RH at a pulling rate of 50 mm / min, and the adhesive strength was evaluated according to the following evaluation criteria: +++ (very excellent): substrate destruction; ++ (excellent): 3 N / cm or more; + (lower practical limit): 1 N / cm or more and less than 3 N / cm; NG (target not achieved): less than 1 N / cm.

[0098] Appearance Evaluation: An adhesive sheet was prepared by applying the adhesive composition to a 50 μm thick PPS film to a dry film thickness of 15 μm and drying at 80°C for 3 minutes. The prepared adhesive sheet was laminated at 120°C to a solid electrolyte membrane (Nafion® NR212, manufactured by Chemours) and then aging in an 80°C electric oven for 7 days. The resulting "PPS / thermocured adhesive composition / solid electrolyte membrane" structure was used as the evaluation structure, and five structures were prepared. These evaluation structures were evaluated according to the following evaluation criteria: ++ (Excellent): No lifting or peeling was observed in all five points. + (Lower limit of practical use): Lifting and / or peeling was observed in one or two points out of five. NG (Failure to achieve target): Lifting and / or peeling was observed in three or more points out of five.

[0099] [Evaluation of Appearance After Heat Resistance Test] Five 10 mm wide evaluation structures consisting of "PPS / thermocured adhesive composition / PPS" obtained above were treated in an electric oven at 200°C for 72 hours. After treatment, the structures were left to stand for 24 hours in an atmosphere of 23°C and 50% RH, and then the appearance was evaluated based on the following evaluation criteria: ++ (excellent): No blistering or peeling was observed in any of the five points. + (lower limit of practical use): Blistering and / or peeling was observed in one or two points out of five. NG (target not achieved): Blistering and / or peeling was observed in three or more points out of five.

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] As can be seen from Tables 5 to 9, the urethane urea resins and their cured products according to the present disclosure obtained favorable results in terms of the heat resistance and moist heat resistance of the urethane urea resin, and the initial adhesive strength, moist heat resistance, heat resistance, and appearance evaluation of the cured products. On the other hand, the comparative resins and their cured products did not obtain satisfactory results in terms of the heat resistance and moist heat resistance of the urethane urea resin, and the initial adhesive strength, moist heat resistance, heat resistance, and appearance evaluation of the cured products.

[0106] The urethane urea resin and its cured product according to the present disclosure can be suitably used in, for example, fuel cells and water electrolysis devices. While the present disclosure has been described above in accordance with specific embodiments, modifications and improvements that are obvious to those skilled in the art are included within the scope of the present disclosure.

[0107] This application claims priority based on Japanese Patent Application No. 2024-099657, filed on June 20, 2024, the disclosure of which is incorporated herein in its entirety by reference.

Claims

1. A urethane urea resin containing a polyol compound (A), a polyisocyanate compound (B), and an amine compound (C) as structural units, wherein at least one of the polyol compound (A), the polyisocyanate compound (B), and the amine compound (C) has an alicyclic structure; the polyol compound (A) contains a diol compound (a1) having a carboxy group and a polycarbonate polyol (a3); the polycarbonate polyol (a3) ​​has an alicyclic structure; the total content of the components having an alicyclic structure is 10.0 to 25.0 mass% out of a total of 100 mass% of the components constituting the urethane urea resin; the acid value of the urethane urea resin is 5 to 30 mgKOH / g; and the urea bond concentration in the urethane urea resin is 0.20 to 1.00 mmol / g.

2. The urethane urea resin according to claim 1, wherein the polyisocyanate compound (B) contains a polyisocyanate (b1) having an alicyclic structure, and the amine compound (C) contains a diamine (c1) having an alicyclic structure.

3. A method for producing the urethane urea resin according to claim 1 or 2 in a mixed solvent containing two solvents: a solvent (S1) having a hydrogen bond term δh of Hansen's solubility parameter of 0 or more but less than 10, and a solvent (S2) having a δh of 10 to 25, wherein the proportion of solvent (S2) in 100% by mass of the mixed solvent is 10 to 40% by mass.

4. An adhesive composition comprising the urethane urea resin of claim 1 or 2 and a curing agent, wherein the curing agent contains at least one compound selected from the group consisting of epoxy compounds, carbodiimide compounds, oxazoline compounds, and aziridine compounds, and wherein the molar ratio (Y / X) of the carboxyl group (X) in the urethane urea resin to the functional group (Y) in the curing agent is 1.0 / 1.0 to 5.0 / 1.

0.

5. A cured product obtained by curing the adhesive composition according to claim 4.

6. An adhesive sheet having an adhesive layer made of the adhesive composition according to claim 4 and a substrate.

7. A fuel cell member comprising the adhesive sheet according to claim 6.

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