Curable resin composition, hardened product

Abstract

The present invention provides a hardening resin composition which is excellent in adhesion, cohesion breaking, and flexibility, and which is suitable for use in the field of structural bonding of automobiles, aircraft, and the like, and which can be used without solvent, and a hardened product. A solvent-free hardening resin composition contains a main agent (X) containing a liquid epoxy resin (A), and a hardening agent (Y) containing a polyurethane urea resin (B) having a primary amino group or a secondary amino group at a terminal, a liquid polyamine (C), and a heterocyclic aromatic compound (D) having two or more adjacent nitrogen atoms in a ring structure, the nitrogen atoms not having a substituent, wherein the polyurethane urea resin (B) is contained at 10 to 80 mass% in 100 mass% of the organic components having a primary amino group and the organic components having a secondary amino group contained in the hardening agent (Y).

Description

Technical Field

[0001] This invention relates to a curable resin composition and its cured form. Background Technology

[0002] In the automotive, aerospace, and other fields, various structural adhesives are used to bond and fix metals such as iron, aluminum, and stainless steel, as well as resins, glass, and ceramics. In recent years, in the automotive and aerospace fields, there has been an active trend towards lightweighting to improve combustion efficiency, increasing the use of plastics or materials containing fiber-reinforced plastics (hereinafter referred to as FRP), or replacing iron with lighter aluminum. This has created a demand for highly reliable adhesives that can firmly bond these materials.

[0003] In addition, in recent years, from the perspectives of environmental protection, energy cost reduction, and worker safety, there has been a demand for solvent-free adhesives or lower curing temperature conditions.

[0004] Epoxy resin compositions are widely used in various fields requiring reliability, such as structural adhesives or sealants for car bodies or automotive parts, and matrix resins, due to their excellent heat resistance, adhesion, mechanical strength, electrical properties, and processability. Among them, two-component curing epoxy adhesives have excellent curing properties, and their viscosity rises slowly after mixing, resulting in excellent workability. Therefore, they are widely used as structural bonding agents.

[0005] On the other hand, epoxy resin curing generally lacks flexibility and is brittle. Therefore, for example, when bonding materials with different coefficients of linear expansion, such as aluminum and FRP, there is a problem that the difference in the coefficients of expansion between the materials caused by temperature changes during the manufacturing process or the operating temperature environment can exert high stress on the adhesive layer, promoting the damage or deterioration of the adhesive layer.

[0006] To address this problem, methods for imparting flexibility to adhesives have been extensively studied as part of stress-relieving designs. For example, various combinations have been investigated, including epoxy-terminated polybutadiene, polyurethane, polyester, and other polymeric epoxy compounds; core-shell rubber particles; amino-terminated polybutadiene; and polyamide amines. (Patent Documents 1-4)

[0007] However, if polymeric epoxy or polymeric amines are used to soften the adhesive components, problems arise such as reduced workability due to increased viscosity from the added amount, or decreased adhesive strength due to disruption of the cross-linking state or compatibility with other components. In particular, with aluminum substrates, which are commonly used as lightweight metals, there is a problem of easy breakage at the substrate interface and insufficient reliability when surface treatments such as primer coating or grinding are not performed. Therefore, there is a need for an adhesive that requires no surface treatment, exhibits high adhesion, low agglomeration resistance, and high reliability with flexibility.

[0008] Patent document 1 discloses that by using core-shell rubber particles as a modifier for epoxy resin, high stress relief and adhesion can be obtained. However, its flexibility is still insufficient, and it is damaged at the substrate interface, thus presenting problems in terms of coagulation destructiveness and flexibility.

[0009] Patent document 2 investigated the softening effect of polyurethane-modified epoxy resin, but a large amount of resin was required to achieve the desired softness, and the resulting increase in viscosity led to a decrease in workability. Furthermore, due to the large resin content, insufficient interfacial adhesion and agglomeration / destructive properties remained issues.

[0010] On the other hand, Patent Document 5 discloses that excellent adhesion and flexibility can be obtained by using an amino-terminated carbamate urea with a chain extended by a diamine having an ether group as a modifier. However, its failure mode is interfacial failure, and a superior adhesive that satisfies high adhesion, coagulation failure, and flexibility is desired.

[0011] [Existing Technical Documents]

[0012] [Patent Literature]

[0013] [Patent Document 1] Japanese Patent Application Publication No. 2015-182248

[0014] [Patent Document 2] Japanese Patent Application Publication No. 2017-002130

[0015] [Patent Document 3] Japanese Patent Application Publication No. 2015-063595

[0016] [Patent Document 4] Japanese Patent Application Publication No. 2018-002766

[0017] [Patent Document 5] Japanese Patent Publication No. 2013-521361 Summary of the Invention

[0018] [The problem the invention aims to solve]

[0019] The purpose of this invention is to provide a curable resin composition that combines excellent adhesion, coagulation-destructive properties, and flexibility, and can be used in a solvent-free environment.

[0020] [Technical means to solve the problem]

[0021] The inventors have made repeated efforts to solve the aforementioned problems and have found that the problems of the present invention can be solved in the following forms, thereby completing the present invention.

[0022] The invention relates to a curable resin composition, which is a solvent-free curable resin composition, characterized in that it contains a main agent (X) comprising a liquid epoxy resin (A) and a curing agent (Y).

[0023] And it satisfies all of the following conditions (i) to (iv).

[0024] (i) The curing agent (Y) comprises polyurethane urea resin (B), liquid polyamine (C) and heterocyclic aromatic compound (D).

[0025] (ii) The polyurethane urea resin (B) has a primary amino or a secondary amino group at the end.

[0026] (iii) A heterocyclic aromatic compound (D) has two or more adjacent nitrogen atoms in a ring structure, wherein the nitrogen atoms are not substituents.

[0027] (iv) Of the total 100% by mass of organic components having primary amino groups and organic components having secondary amino groups contained in the curing agent (Y), 10% to 80% by mass of polyurethane urea resin (B) is included.

[0028] In addition, the present invention relates to the curable resin composition according to technical solution 1, wherein the molecular weight of the liquid polyamine (C) is less than 600.

[0029] In addition, the present invention relates to the curable resin composition according to technical solution 1, wherein the polyurethane urea resin (B) has an average molecular weight of 1,000 or more and less than 50,000.

[0030] In addition, the present invention relates to the curable resin composition according to technical solution 1, wherein, in a total of 100% by mass of the polyurethane urea resin (B), liquid polyamine (C) and heterocyclic aromatic compound (D), 0.3% to 7.0% by mass of heterocyclic aromatic compound (D) is contained.

[0031] In addition, the present invention relates to a hardened material comprising the aforementioned hardening resin composition.

[0032] [The effects of the invention]

[0033] This invention provides a curable resin composition that combines excellent adhesion, coagulation resistance, and flexibility, and can be used in a solvent-free environment. The curable resin composition of this invention is particularly preferred for use in structural bonding applications such as automotive and aircraft where high reliability is required. Detailed Implementation

[0034] The present invention will now be described in detail. Furthermore, other embodiments consistent with the spirit of the present invention are also included within the scope of the present invention. Additionally, in this specification, the numerical range specified by "~" is defined as a range including the values ​​described before and after "~" as the lower and upper limits. Furthermore, unless otherwise specified, each component appearing in this specification may be used independently or in combination with two or more.

[0035] In this specification, the term "main agent" refers to the main agent in a two-component curable resin composition, and the term "curing agent" refers to the curing agent in a two-component curable resin composition.

[0036] In this specification, "solvent-free" means that volatile organic solvents are not intentionally added, and the content of volatile organic solvents that do not participate in the curing reaction in the curing resin composition is less than 3% by mass.

[0037] The solvent-free curable resin composition of the present invention is a solvent-free curable resin composition characterized by containing a main agent (X) comprising liquid epoxy resin (A) and a curing agent (Y).

[0038] And it satisfies all of the following conditions (i) to (iv).

[0039] (i) The curing agent (Y) comprises polyurethane urea resin (B), liquid polyamine (C) and heterocyclic aromatic compound (D).

[0040] (ii) The polyurethane urea resin (B) has a primary amino or a secondary amino group at the end.

[0041] (iii) A heterocyclic aromatic compound (D) has two or more adjacent nitrogen atoms in a ring structure, wherein the nitrogen atoms are not substituents.

[0042] (iv) Of the total 100% by mass of organic components having primary amino groups and organic components having secondary amino groups contained in the curing agent (Y), 10% to 80% by mass of polyurethane urea resin (B) is included.

[0043] By satisfying all of the above conditions, when the main agent (X) and the curing agent (Y) form a crosslinked structure, the heterocyclic aromatic compound (D) interacts firmly between the polyurethane urea resin (B) and the substrate interface. Furthermore, due to the formation of a moderate phase separation structure, it exhibits excellent flexibility while maintaining high adhesion and preventing agglomeration and destructive behavior. Therefore, the curable resin composition of the present invention is preferably used as a structural adhesive in structural bonding applications such as automobiles and aircraft where high reliability is required. In addition, the curable resin composition of the present invention is a liquid, solvent-free adhesive, which is also excellent from the viewpoint of safety and environmental impact.

[0044] [Main Agent (X)]

[0045] The main component (X) contains liquid epoxy resin (A). The main component (X) may also contain other epoxy compounds besides the liquid epoxy resin (A) that facilitate the crosslinking reaction with the curing agent (Y), as well as additives, as needed.

[0046] Liquid Epoxy Resin (A)

[0047] As for the liquid epoxy resin (A), there are no particular limitations as long as it is a compound that is liquid at room temperature (23°C), but it is preferable to have two or more epoxy groups in the molecule. Furthermore, the epoxy equivalent is preferably 200 g / eq or less, more preferably 150 g / eq to 200 g / eq. The epoxy equivalent of the liquid epoxy resin (C) can be determined by measurement according to Japanese Industrial Standards (JIS) K-7236. In addition, the epoxy equivalent of the liquid epoxy resin (A) in this specification refers to the epoxy equivalent of each epoxy resin used.

[0048] Liquid epoxy resin (A) contributes to excellent adhesion by being incorporated into the cross-linked structure during curing.

[0049] Examples of liquid epoxy resins (A) include aromatic epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, and polyether epoxy resins. Among these, aromatic epoxy resins and alicyclic epoxy resins exhibit excellent adhesion and are therefore preferred. Aromatic epoxy resins are more preferred in terms of ease of availability and good curing and adhesion.

[0050] Examples of aromatic epoxy resins include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, aromatic epoxy resins with an ester skeleton, aromatic glycidylamine type epoxy resin, cashew phenol modified epoxy resin, p-tert-butylphenol glycidyl ether, phenyl glycidyl ether, tolyl glycidyl ether, etc. Among aromatic epoxy resins, bisphenol A type epoxy resin is preferred.

[0051] Examples of alicyclic epoxy resins include: hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, alicyclic glycidylamine type epoxy resin, alicyclic epoxy resin with ester skeleton, cyclohexane type epoxy resin, cyclohexanediethanol type epoxy resin, limonene dioxide, etc.

[0052] Examples of aliphatic epoxy resins include: 1,6-hexanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, propylene glycol diglycidyl ether, 2-ethylhexyl monoglycidyl ether, glyceryl glycidyl ether, trimethylolpropane triglycidyl ether, etc.

[0053] Examples of polyether epoxy resins include: polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether.

[0054] The ratio of the total molar number of all epoxy groups in the curable resin composition to the total molar number of all primary and secondary amino groups (epoxy groups / active hydrogen groups of primary and secondary amino groups) is preferably in the range of 0.5 to 2.0, more preferably 0.6 to 1.5. In the range of 0.5 to 2.0, there are fewer unreacted functional groups, resulting in a good crosslinking density and exhibiting high flexibility and adhesion.

[0055] <Other Epoxy Compounds>

[0056] There are no particular limitations on other epoxy resins, as long as they are epoxy resins other than liquid epoxy resins (A) and are epoxy compounds cured by a curing agent (Y). Examples include solid epoxy resins.

[0057] <Additives>

[0058] Examples of additives include: silane coupling agents, leveling agents or defoamers, fillers, propellants, plasticizers, superplasticizers, wetting agents, flame retardants, viscosity modifiers, preservatives, stabilizers, and colorants, among other known additives. The following compounds may be listed as examples of such additives, but are not limited to these.

[0059] Examples of silane coupling agents include: vinyltrimethoxysilane, vinyltriethoxysilane, and other vinyl-containing trialkoxysilanes; 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and other amino-containing trialkoxysilanes; 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and other glycidyl groups; 3-isocyanatepropyltriethoxysilane, and other isocyanate groups; 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and other mercapto groups. The amount of the silane coupling agent is preferably 0.05 to 10 parts by mass relative to 100 parts by mass of the total organic components of the main agent (X).

[0060] Examples of leveling agents include: polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, polyester-modified hydroxyl-containing polydimethylsiloxane, polyether ester-modified hydroxyl-containing polydimethylsiloxane, acrylic copolymers, methacrylic copolymers, polyether-modified polymethylalkylsiloxane, alkyl acrylate copolymers, alkyl methacrylate copolymers, lecithin, etc.

[0061] Examples of defoamers include silicone resins, silicone solutions, copolymers of alkyl vinyl ethers with alkyl acrylates and alkyl methacrylates, and other known defoamers.

[0062] [Hardening agent (Y)]

[0063] The curing agent (Y) contains a polyurethane urea resin (B) having a primary or secondary amino group at the end, a liquid polyamine (C), and a heterocyclic aromatic compound (D). The curing agent (Y) is not limited to the polyurethane urea resin (B), liquid polyamine (C), and heterocyclic aromatic compound (D), and may, as needed, also contain other amine compounds, curing accelerators, and additives that facilitate crosslinking with the epoxy resin (A) in the main agent (X).

[0064] Polyurethane urea resin (B)

[0065] Polyurethane urea resin (B) has a primary or secondary amino group at the end. Polyurethane urea resin (B) can be obtained, for example, by reacting a polyol, a polyisocyanate, and a polyamine in a manner where the amino group in the polyamine remains. For excellent agglomeration-disrupting properties, the terminal amino group is preferably primary.

[0066] The average molecular weight of the polyurethane urea resin (B) is not particularly limited, but is preferably 1,000 or more and less than 50,000. A molecular weight of 1,000 or more results in excellent flexibility, while a molecular weight of less than 50,000 results in low viscosity, making it easy to adjust the viscosity in solvent-free conditions. More preferably, it is 2,000 or more and less than 48,000.

[0067] The number average molecular weight of polyurethane urea resin (B) was determined by gel permeation chromatography as a conversion value based on standard polystyrene, as detailed in the examples.

[0068] <Polyols>

[0069] Polyols are compounds with two or more hydroxyl groups in their molecules. Representative polyols include: polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, and vegetable oil-based polyols.

[0070] Furthermore, examples of compounds having two or more hydroxyl groups within the molecule include: polyols obtained by adding alkylene oxides such as methylene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, or polyoxytetramethylene oxide to compounds having at least two active hydroxyl groups, such as low molecular weight polyols, aliphatic amines, aromatic amines, alkanolamines, or bisphenols.

[0071] Examples of low molecular weight polyols include, for example, difunctional low molecular weight polyols or low molecular weight polyols with more than three functionalities.

[0072] There are no particular limitations on difunctional low-molecular-weight polyols. Examples include: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentylene glycol, hexanediol, octyl glycol, 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-octyl glycol, polyoxyethylene glycol (addition molar number less than 10), polyoxypropylene glycol (addition molar number less than 10), cyclohexanediol, cyclohexanediethanol, tricyclodecanediethanol, cyclopentadienediethanol, and dimer. Diol), bisphenol A, N,N-bis(2-hydroxypropyl)aniline, dihydroxymethylacetic acid, dihydroxymethylpropionic acid, dihydroxymethylbutyric acid, 2,2-dihydroxymethylbutyric acid, 2,2-dihydroxymethylvaleric acid, dihydroxysuccinic acid, dihydroxypropionic acid, dihydroxybenzoic acid, etc.

[0073] There are no particular limitations on low-molecular-weight polyols with trifunctionality or higher. Examples include: trimethylolethane, trimethylolpropane, 1,1,1-trimethylolbutane, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,6-butanetriol, trimethylolbutene, trimethylolpentene, trimethylolhexene, trimethylolhepene, trimethyloloctene, trimethylolnonene, trimethyloldecene, trimethylolundecene, trimethyloldodecene, and trimethyloldecene. Triene, trimethylolpentadene, trimethylolhexadecene, trimethylolheptadecene, trimethylolheptadecene, trimethyloloctadecene, 1,1,1-trimethylol-2-methylhexane, 1,1,1-trimethylol-3-methylhexane, 1,1,1-trimethylol-2-ethylhexane, 1,1,1-trimethylol-3-ethylhexane, 1,2,3-octanetriol, 1,3,7-octanetriol, 3,7-dimethyl-1,2,3-octanetriol, 1,1,1-1 1,1-Tris(hydroxymethyl)decane, 1,2,10-decanetriol, 1,1,1-Tris(hydroxymethyl)isoheptadecane, 1,1,1-Tris(hydroxymethyl)sec-butane, 1,1,1-Tris(hydroxymethyl)tert-pentane, 1,1,1-Tris(hydroxymethyl)tert-nonane, 1,1,1-Tris(hydroxymethyl)tert-tridecane, 1,1,1-Tris(hydroxymethyl)tert-heptadecane, 1,1,1-Tris(hydroxymethyl)-2-methylhexane, 1,1,1-Tris(hydroxymethyl)-3-methylhexane, 1,1 1-Trimethylol-2-ethylhexane, 1,1,1-Trimethylol-3-ethylhexane, 1,1,1-Trimethylol-isoheptadecane, 1,2,3,4-Butanetetrol, Pentaerythritol, Dipentaerythritol, Tripentaerythritol, Glycerin, Diglycerol, Triglyceride, Polyglycerol, Di-Trimethylolethane, Di-Trimethylolpropane, Tris(2-hydroxyethyl)isocyanurate, Benzene-1,3,5-triol, Benzene-1,2,3-triol, Stilbene-3, ,5-triol, sucrose, inositol, sorbitan, sorbitol, mannitol, saccharose, cellulose, xylitol, etc.

[0074] Examples of aliphatic amine compounds include ethylenediamine, triethylenetetramine, diethylenetriamine, and triaminopropane. Examples of aromatic amine compounds include toluenediamine and diphenylmethane-4,4-diamine.

[0075] Examples of alkanolamines include ethanolamine and diethanolamine. Examples of bisphenols include bisphenol A, bisphenol AP, bisphenol B, bisphenol C, bisphenol E, and bisphenol F.

[0076] Examples of polyether polyols include: polyethylene glycol, polypropylene glycol, and poly(ethylene / propylene) glycol, which are polymers or copolymers of methylene oxide, ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, etc. Additionally, examples include polyether polyols obtained by the condensation of hexanediol, methylhexanediol, heptanediol, octanediol, or mixtures thereof.

[0077] Examples of polyester polyols include: polyester polyols obtained by condensation reaction of the low molecular weight polyol with a diacid component.

[0078] Examples of dicarboxylic acid components include: terephthalic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, hydrogenated dimer acid, phthalic anhydride, isophthalic acid, trimellitic acid, glutaric acid, pimelic acid, octanoic acid, sebacic acid, and other aliphatic or aromatic dicarboxylic acids, as well as their anhydrides.

[0079] Additionally, examples include polyester polyols obtained through the ring-opening polymerization of cyclic ester compounds such as ε-caprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone.

[0080] Examples of polycarbonate polyols include reaction products obtained by reacting the low molecular weight polyol with carbonate compounds such as dialkyl carbonate, alkylene carbonate, and diaryl carbonate.

[0081] In addition, examples of dialkyl carbonates include dimethyl carbonate and diethyl carbonate; examples of alkylene carbonates include ethylene carbonate; and examples of diaryl carbonates include diphenyl carbonate.

[0082] Examples of polyolefin polyols include: hydroxyl-containing polybutadiene, hydrogenated hydroxyl-containing polybutadiene, hydroxyl-containing polyisoprene, hydrogenated hydroxyl-containing polyisoprene, hydroxyl-containing chlorinated polypropylene, and hydroxyl-containing chlorinated polyethylene.

[0083] Examples of plant-based polyols include polyols made from plant-derived castor oil, dimer acid, or soybean oil.

[0084] Among these, polyether polyols and polycarbonate polyols are preferred due to their excellent flexibility.

[0085] The number average molecular weight of the polyol is preferably 300 to 5,000, more preferably 400 to 3,500. A number average molecular weight of 300 to 5,000 results in better adhesion and flexibility of the obtained cured material, and is therefore preferred.

[0086] The number-average molecular weight of the polyols was determined by gel permeation chromatography as a conversion value based on standard polystyrene, as detailed in the examples.

[0087] Furthermore, the polyol can also be used in combination with the low molecular weight polyol for the purpose of adjusting the concentration of urethane bonds or introducing various functional groups, without compromising the effects of the present invention.

[0088] <Polyisocyanate>

[0089] Polyisocyanates are any compounds having two or more isocyanate groups within their molecules, such as aromatic, aliphatic, or alicyclic diisocyanates. Polyisocyanates with aromatic or alicyclic structures are preferred. Having an aromatic or alicyclic structure provides adequate deagglomeration due to its steric hindrance, resulting in excellent flexibility; therefore, aromatic and alicyclic diisocyanates are preferred. Furthermore, the molecular weight of the polyisocyanate is preferably less than 300. If the molecular weight is less than 300, the urethane bonds and urea bonds are well approximated, resulting in excellent deagglomeration resistance and flexibility; therefore, this is also preferred.

[0090] Examples of aromatic diisocyanates include: 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4, -Diphenylmethane diisocyanate, 2,4-Diphenylmethane diisocyanate, 2, -Diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, benzyltoluidine diisocyanate, phenyl diisocyanate, m-tetramethylxylene diisocyanate, p-tetramethylxylene diisocyanate, 3, -dimethyl-4, -Biphenyl diisocyanate, 3, -dimethoxy-4, -Biphenyl diisocyanate, 3, -dichloro-4, -Biphenyl diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, etc.

[0091] Examples of aliphatic diisocyanates include: trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylidene diisocyanate, 2,3-butylidene diisocyanate, 1,3-butylidene diisocyanate, dodecyl diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, lysine ester triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, tetramethylene diisocyanate, and trimethylhexamethylene diisocyanate.

[0092] Examples of alicyclic diisocyanates include: isophorone diisocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4, - Methylene bis(cyclohexyl isocyanate), 1,4-bis(isocyanate methyl)cyclohexane, hydrogenated phenyl dimethyl diisocyanate, dimer acid diisocyanate, norbornene diisocyanate, etc.

[0093] <Polyamines>

[0094] The polyamine is not particularly limited as long as it is a compound having two or more amino groups within its molecule, but diamines are preferred. Examples include aromatic diamines, aliphatic diamines, alicyclic diamines, or polyether diamines. The molecular weight of the polyamine is preferably less than 400. If the molecular weight is less than 400, the reaction site is well-proximated to the urea bond during cross-linking, resulting in excellent adhesion. A molecular weight of less than 300 is preferred. Furthermore, the polyamine preferably has an aromatic ring or alicyclic structure within its molecule. Having an aromatic ring or alicyclic structure results in a moderate cross-linking density due to steric hindrance, leading to excellent flexibility; therefore, aromatic diamines and alicyclic diamines are preferred.

[0095] Examples of aromatic diamines include: m-xylene diamine, p-xylene diamine, and m-phenylenediamine.

[0096] Examples of aliphatic diamines include: ethylenediamine, diaminopropane, diaminobutane, diaminohexane, 2,5-dimethylhexamethylenediamine, hexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, and iminodipropylamine.

[0097] Examples of alicyclic diamines include isophorone diamine and 1,3-bis(aminomethyl)cyclohexane.

[0098] As a polyether diamine, there are no particular limitations as long as it is a compound having two amino groups in the molecule and a repeating ether chain structure. Examples include: poly(propylene glycol) diamine, poly(ethylene glycol) diamine, poly(tetramethylene ether diamine), poly(propylene glycol / ethylene glycol) diamine, etc.

[0099] There are no limitations on the manufacturing method of polyurethane urea resin (B), but it is preferably manufactured by the following method.

[0100] Step 1: The polyol and polyisocyanate are subjected to a urethane esterification reaction under the condition that the isocyanate group is in excess relative to the hydroxyl group to obtain a urethane prepolymer with isocyanate groups at the molecular end.

[0101] Step 2: Ureaming reaction of urethane prepolymer and polyamine under conditions of excess amino groups relative to isocyanate groups to obtain polyurethane urea resin (B) with primary or secondary amino groups at the ends.

[0102] Both steps 1 and 2 can be carried out using a solvent, or they can be carried out without a solvent. If a solvent is used in steps 1 and 2, the solvent is removed under reduced pressure or normal pressure during the reaction or after the reaction is completed, thereby obtaining a solvent-free polyurethane urea resin (B).

[0103] The carbamate reaction in step 1 and the urea reaction in step 2 can be carried out using known reactions, with a catalyst used to adjust the reactivity.

[0104] As catalysts, known metal-based catalysts and amine-based catalysts can be used. Examples of metal-based catalysts include: dibutyltin dilaurate, tin octanoate, dibutyltin di(2-ethylhexanoate), lead 2-ethylhexanoate, 2-ethylhexyl titanate, titanium ethyl acetate, iron 2-ethylhexanoate, cobalt 2-ethylhexanoate, zinc naphthenate, cobalt naphthenate, tetra-n-butyltin, etc. Examples of amine-based catalysts include tertiary amines such as tetramethylbutanediamine. The amount of catalyst used is preferably in the range of 0.01 to 0.05 parts by mass, based on the total mass of the polyol and polyisocyanate.

[0105] The content of polyurethane urea resin (B) is 10% to 80% by mass of the total 100% by mass of organic components with primary amino groups and organic components with secondary amino groups contained in the curing agent (Y). By setting this range, phase separation formation is promoted, resulting in excellent adhesion and flexibility, and is therefore preferred. More preferably, it is 15% to 75% by mass. The organic components with primary amino groups and organic components with secondary amino groups contained in the curing agent (Y) refer to the organic components with primary amino groups, organic components with secondary amino groups, and organic components containing both primary and secondary amino groups in the polyurethane urea resin (B), liquid polyamine (C), heterocyclic aromatic compounds (D) and other amine compounds, curing accelerators, and additives.

[0106] Liquid Polyamines (C)

[0107] As a liquid polyamine (C), any compound that is liquid at room temperature (23°C) and has two or more primary or secondary amino groups within its molecule is acceptable. Examples include aromatic polyamine compounds, aliphatic polyamine compounds, alicyclic polyamine compounds, and polyether polyamine compounds. To achieve excellent adhesion and flexibility, polyether polyamine compounds or alicyclic polyamine compounds are preferred.

[0108] Examples of aromatic polyamine compounds include: m-xylene diamine, 4, -methylenebis(N-sec-butylaniline), diethyltoluenediamine, dimethylthiotoluenediamine, aminobenzylamine, N, -Di-sec-butyl-p-phenylenediamine, 2,4-diamino-3,5-diethyltoluene, 2,6-diamino-3,5-diethyltoluene, etc.

[0109] Examples of aliphatic polyamine compounds include: ethylenediamine, diaminopropane, diaminobutane, diaminohexane, 2,5-dimethylhexamethylenediamine, hexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, and iminodipropylamine.

[0110] Examples of alicyclic polyamine compounds include: isophorone diamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornene, 1,2-cyclohexanediamine, 4, -Methylenebis(N-tert-butylcyclohexaneamine), 4, Methylenebis(2-methylcyclohexylamine), aminoethylpiperazine, 2-(aminomethyl)piperidine, 1-(2-aminoethyl)piperidine, dimer diamine, etc.

[0111] Examples of polyether polyamine compounds include: poly(propylene glycol) diamine, poly(propylene glycol) triamine, poly(ethylene glycol) diamine, poly(ethylene glycol) triamine, poly(tetramethylene ether glycol) diamine, poly(tetramethylene ether glycol) triamine, poly(propylene glycol / ethylene glycol) diamine, and poly(propylene glycol / ethylene glycol) triamine.

[0112] The molecular weight of the liquid polyamine (C) is preferably less than 600. If the molecular weight is less than 600, a hardened material with excellent adhesion can be obtained by forming a good cross-linking structure. More preferably, the molecular weight is less than 560. Furthermore, the molecular weight of the liquid polyamine (C) is the sum of the atomic weights contained in the molecular formula and is calculated.

[0113] The curing speed can be adjusted by combining the polyether polyamine compound or the alicyclic polyamine compound with an aliphatic polyamine compound. When combining the polyether polyamine compound or the alicyclic polyamine compound with an aliphatic polyamine compound for the purpose of adjusting the curing speed, the content of the aliphatic polyamine compound is preferably in the range of 3% to 20% by mass of the total 100% by mass of the liquid polyamine (C).

[0114] Heterocyclic Aromatic Compounds (D)

[0115] As a heterocyclic aromatic compound (D), any aromatic compound having two or more adjacent nitrogen atoms in the ring structure and without substituents on the two adjacent nitrogen atoms is acceptable. Examples include azoles of hetero five-membered rings, hetero six-membered ring compounds, hetero fusion ring compounds, etc.

[0116] Examples of azoles include: 1,2-pyrazole, methylpyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole, 1,2,4-triazole, 1,2,3-triazole, tetrazolium, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,3,4-thiadiazole, pentaazole, and their derivatives.

[0117] Examples of heterohexa-membered ring compounds include: pyridazine, 1,2,3-triazine, 1,2,4-triazine, 1,2,3,4-tetraazine, 1,2,4,5-tetraazine, and their derivatives.

[0118] Examples of heterocyclic compounds include: 1,2,3-benzotriazole, 5-methylbenzotriazole, 7-azainazole, zoline, benzo-C-zoline, etc.

[0119] Among these, azoles are preferred due to their excellent adhesive and agglomeration-destructive properties. From the viewpoint of availability and agglomeration-destructive properties, 1,2-pyrazole, 3,5-dimethylpyrazole, and 1,2,4-triazole are more preferred.

[0120] Regarding the heterocyclic aromatic compound (D), it is preferable to include 0.3% to 7.0% by mass of the heterocyclic aromatic compound (D) in a total of 100% by mass of polyurethane urea resin (B), liquid polyamine (C), and heterocyclic aromatic compound (D). If it is 0.3% by mass or more, the adhesion and coagulation resistance are improved due to the good interaction between the two adjacent nitrogen atoms at the interface between the polyurethane urea resin (B) and the substrate. If it is 7.0% by mass or less, the coagulation resistance and flexibility are improved. More preferably, it is 0.5% to 5.0% by mass.

[0121] Other Amine Compounds

[0122] Other amine compounds refer to amine compounds other than the polyurethane urea resin (B), liquid polyamine (C), and heterocyclic aromatic compounds (D). As other amine compounds, known amines that cure epoxy resins can be used, provided they do not impair flexibility. Examples include aromatic polyamine compounds, aliphatic polyamine compounds, alicyclic polyamine compounds, polyether polyamine compounds, amide compounds, and monofunctional amines that are solid at room temperature.

[0123] Hardening Accelerator

[0124] Examples of hardening accelerators include: tertiary amines and their salts, imidazoles and their salts, urea compounds, phosphorus compounds, organophosphorus compounds and their salts, zinc octoate, tin octoate and other metal salts, phenols or alcohols and other compounds with hydroxyl groups, Lewis acids, and amine complex salts.

[0125] The curing accelerator preferably comprises 0.01% to 25% by mass of the total organic components of the curing agent (X). Furthermore, the term "total organic components of the curing agent (X)" refers to the organic components excluding inorganic fillers.

[0126] "additive"

[0127] The additives may be the same as those described as additives that may be contained in the main ingredient (X).

[0128] [[Curing Resin Composition]]

[0129] The method for manufacturing the curable resin composition of the present invention is not particularly limited, and can be obtained by mixing a main agent (X) comprising liquid epoxy resin (A) and a curing agent (Y) comprising polyurethane urea resin (B), liquid polyamine (C) and heterocyclic aromatic compound (D) using a known method.

[0130] [[Hardened material]]

[0131] The cured product of the present invention can be obtained by curing the curable resin composition under conditions, for example, 5°C to 180°C.

[0132] The cured product of the present invention can be used as a composite. A composite is a laminate having a layer containing the cured product on a substrate, or a cured product obtained by impregnating and curing a curable resin as a matrix resin in fibers or the like. It can be obtained by compounding the cured product of the curable resin composition of the present invention with any substrate.

[0133] Laminates can be formed using known lamination methods. For example, by coating one side of a substrate with a curable resin composition, then overlapping another substrate with a layer of the curable resin composition before curing, and curing it at 5°C to 180°C, a laminate having a substrate and a layer containing the curable resin composition can be obtained. If the mixture is used at an internal temperature of 20°C to 40°C, it promotes the formation of phase separation structures and exhibits excellent flexibility, thus it is preferred. From the viewpoint of reducing environmental impact, curing it at room temperature is more preferable.

[0134] There are no particular limitations on the substrate used for the laminate. Preferred substrates include, for example, metals such as stainless steel or aluminum, thermoplastic polymers such as polyethylene, polyurethane, polyacrylate and polycarbonate and copolymers thereof, thermosetting polymers such as vulcanized rubber, urea-formaldehyde foam, melamine resin, wood, carbon fiber reinforced plastics, glass fiber reinforced plastics and other fiber reinforced plastics.

[0135] The curable resin composition of the present invention can be used for bonding between various substrates. The substrates to be bonded can be the same or different. When used as an adhesive, the ideal film thickness of the curable resin composition is 10 μm to 10 mm.

[0136] The curable resin composition of the present invention has high adhesiveness, as well as coagulation and destructive properties and flexibility. Laminates of the curable resin composition are useful as adhesives for structures requiring high reliability, such as automobiles or large structures.

[0137] When using a curable resin composition as a matrix resin, it can be obtained by mixing the curable resin composition using a known method, impregnating it in fibers or the like, and then curing it at a temperature of 20°C to 180°C. To exhibit high adhesion by forming a good cross-linked structure, curing at a temperature of 60°C to 150°C is preferred. From the viewpoint of reducing environmental impact, a temperature of 130°C or lower is more preferable. In the case of heat curing, pre-curing at a temperature below the glass transition temperature followed by formal curing at a temperature above the glass transition temperature results in a better formation of the cross-linked structure, which is therefore preferable.

[0138] The curable resin composition of the present invention has high substrate adhesion and excellent flexibility, and composites using the curable resin composition as a matrix resin are useful in applications such as pressure vessels or wind turbine blades.

[0139] [Example]

[0140] The present invention will be described in more detail below through embodiments, but these embodiments do not limit the scope of the invention in any way. Furthermore, unless otherwise specified, "parts" in the embodiments refers to "parts by mass," and "%" refers to "% by mass." Additionally, "-" in the table indicates that the mixture was not mixed.

[0141] <Number Average Molecular Weight (Mn)>

[0142] The number-average molecular weights of the polyols and polyurethane urea resin (B) were calculated using gel permeation chromatography (GPC) as conversions based on standard polystyrene. For the determination, an ACQUITY UPLC (Ultra Performance Liquid Chromatography) (Waters Corporation) was used, with 3 mM triethylamine and 10 mM LiBr in N,N-dimethylformamide as the eluent. Three TSK gelSuper HM-M (Tosoh Corporation) columns were connected in series as a column, and the determination was performed at a flow rate of 0.6 mL / min, an injection volume of 10 μL, and a column temperature of 40°C.

[0143] <Amine value>

[0144] The amine value was determined according to JIS K-7237.

[0145] The following are the abbreviations for the compounds in Table 1.

[0146] <Polyols>

[0147] P-400: Difunctional polypropylene glycol, quantity average molecular weight 450, manufactured by ADEKA.

[0148] P-2000: Difunctional polypropylene glycol, quantity average molecular weight 2,000, manufactured by ADEKA.

[0149] C-1090: Difunctional polycarbonate polyol, quantity average molecular weight 1,000, manufactured by Kuraray Corporation.

[0150] C-2090: Difunctional polycarbonate polyol, quantity average molecular weight 2,000, manufactured by Kuraray Corporation.

[0151] PH-300: Difunctional polycarbonate polyol, quantity average molecular weight 3,000, manufactured by UBE Corporation.

[0152] <Polyisocyanate>

[0153] IPDI: Isophorone diisocyanate, molecular weight 222

[0154] TODI: 3, -dimethyl-4, -Biphenyl diisocyanate (3, -dimethyl-4, -biphenylenediisocyanate), molecular weight 264

[0155] HDI: Hexamethylene diisocyanate, molecular weight 168

[0156] <Polyamines>

[0157] IPDA: Isophorone diamine, molecular weight 170, amine value 659 mgKOH / g: an organic component with primary amino and alicyclic structures.

[0158] MXDA: m-xylene diamine, molecular weight 136, amine value 824 mgKOH / g: an organic component with primary amino and aromatic ring structures.

[0159] D-230: Polyoxypropylene diamine, molecular weight 230, amine value 490 mgKOH / g, manufactured by Huntsman Corporation: an organic component with primary amino groups.

[0160] D-400: Polyoxypropylene diamine, molecular weight 430, amine value 261 mgKOH / g, manufactured by Huntsman Corporation: an organic component with primary amino groups.

[0161] N-(2-Aminoethyl)piperazine: Molecular weight 129, amine value 870 mgKOH / g, manufactured by Huntsman Corporation: An organic component containing primary and secondary amino groups.

[0162] N,N-Diethyl-1,3-diaminopropane: Molecular weight 130, amine value 863 mgKOH / g, manufactured by Huntsman Corporation: An organic component containing primary and tertiary amino groups.

[0163] (Manufacturing Example 1)

[0164] In a dropping container including a nitrogen inlet tube, a stirrer, a thermometer, and a reflux condenser, 69.7 parts of C-2090 as a polyol, 18.4 parts of TODI as a polyisocyanate, and 0.01% of dibutyltin dilaurate as a catalyst (based on the total mass of the polyol and polyisocyanate) were added and stirred uniformly. The mixture was reacted at 100°C for 2 hours under a nitrogen atmosphere to synthesize an isocyanate-terminated prepolymer. Then, 50 parts of ethyl acetate were added to prepare an isocyanate-terminated prepolymer solution. Subsequently, in another container including a nitrogen inlet tube, a stirrer, a thermometer, and a reflux condenser, 11.9 parts of IPDA and 50 parts of ethyl acetate were added and stirred uniformly at 40°C under a nitrogen atmosphere. Simultaneously, the isocyanate-terminated prepolymer solution was added dropwise over 30 minutes, followed by stirring for 1 hour to obtain a polyurethane urea resin solution with primary amino groups at the ends. The solvent in the obtained polyurethane urea resin solution was removed under reduced pressure to obtain polyurethane urea resin (B-1). The endpoint of the reaction was determined by Fourier transform infrared spectroscopy (FT-IR) through the absorption originating from the isocyanate group (2270 cm⁻¹). -1 The disappearance of the nearby area was used for confirmation. The obtained polyurethane urea resin (B-1) had an average molecular weight of 4000 and an amine value of 28.3 mgKOH / g.

[0165] (Manufacturing Examples 2-3, 5-8, and Comparative Manufacturing Example 1)

[0166] Except for changing the compounds and formulations to those shown in Table 1, the same operations as in Manufacturing Example 1 were performed to obtain Manufacturing Examples 2 to 3, Manufacturing Examples 5 to 8, and the polyurethane urea resins (B-2 to B-3, B-5 ​​to B-8, P-1) of Comparative Manufacturing Example 1. The number-average molecular weight and amine value of the obtained polyurethane urea resins (B-2 to B-3, B-5 ​​to B-8, P-1) are shown in Table 1.

[0167] (Manufacturing Example 4)

[0168] In a dropping container including a nitrogen inlet tube, a stirrer, a thermometer, and a reflux condenser, 8.3 parts of P-400 as a polyol, 8.2 parts of IPDI as a polyisocyanate, and 0.01% of dibutyltin dilaurate as a catalyst (based on the total mass of the polyol and polyisocyanate) were added and stirred uniformly. The mixture was stirred and reacted at 100°C for 2 hours under a nitrogen atmosphere to synthesize an isocyanate-terminated prepolymer. Then, 50 parts of ethyl acetate were added to prepare an isocyanate-terminated prepolymer solution. Subsequently, in another container including a nitrogen inlet tube, a stirrer, a thermometer, and a reflux condenser, 83.5 parts of D-230 and 50 parts of ethyl acetate were added and stirred uniformly at 40°C under a nitrogen atmosphere. The isocyanate-terminated prepolymer solution was added dropwise over 30 minutes, and the mixture was stirred and reacted for 1 hour to obtain a mixed solution of polyurethane urea resin (A-4) with primary amino groups at the ends and liquid polyamine (D-230). The solvent in the obtained mixed solution was removed under reduced pressure to obtain a mixture of polyurethane urea resin (B-4): liquid polyamine (D-230) = 70:30 (mass ratio). The endpoint of the reaction was determined by FT-IR using the absorption from isocyanate groups (2270 cm⁻¹). -1 The disappearance of the nearby area was used for confirmation. The number of polyurethane urea resins (B-4) obtained had an average molecular weight of 1200, and the amine value of the mixed solution was 358 mgKOH / g.

[0169] (Comparative Manufacturing Example 2)

[0170] 865 g of hydrogenated dimer acid, 600 g of soybean oil fatty acids, 945 g of tetraethylenepentamine, and 0.3 g of iron powder were added to a reaction vessel including a nitrogen inlet tube, a stirrer, a thermometer, and a moisture trap. The reaction was carried out at 200°C for 1 hour under a nitrogen atmosphere to obtain polyamide amine (P-2). The amine value of the obtained polyamide amine (P-2) was 390 mgKOH / g.

[0171] [Table 1]

[0172] Table 1

[0173]

[0174] The following are abbreviations for the compounds listed in Tables 2 to 4.

[0175] <Liquid Epoxy Resin (A)>

[0176] jER828: Bisphenol A type epoxy resin, epoxy equivalent 190 g / eq, manufactured by Mitsubishi Chemical Corporation.

[0177] jER806: Bisphenol F type epoxy resin, epoxy equivalent 170 g / eq, manufactured by Mitsubishi Chemical Corporation.

[0178] Tetrad-X: N,N, , -Tetraglycidyl-m-xylenediamine, epoxy equivalent 98 g / eq, manufactured by Mitsubishi Gas Chemical Company

[0179] EX-252: Hydrogenated bisphenol A type epoxy resin, epoxy equivalent 213 g / eq, manufactured by Nagase ChemteX Co., Ltd.

[0180] <Liquid Polyamine (C)>

[0181] D-230: Polyoxypropylene diamine, molecular weight 230, amine value 490 mgKOH / g, manufactured by Huntsman Corporation: an organic component with primary amino groups.

[0182] D-400: Polyoxypropylene diamine, molecular weight 430, amine value 261 mgKOH / g, manufactured by Huntsman Corporation: an organic component with primary amino groups.

[0183] T-3000: Polyoxypropylene diamine, molecular weight 3000, amine value 445 mgKOH / g, manufactured by Huntsman Corporation.

[0184] PRIAMINE 1075: a dimerized diamine, molecular weight 550, amine value 205 mgKOH / g, manufactured by Cargill: an organic component with primary amino groups.

[0185] TETA: Triethylenetetramine, molecular weight 146: an organic component containing primary and secondary amino groups.

[0186] <Amine compounds>

[0187] P-1: Comparative manufacturing example 1: Polyurethane urea resin with tertiary amino groups at the ends: Organic components with tertiary amino groups

[0188] P-2: Comparatively, the polyamide amine resin manufactured in Example 2 contains organic components with primary and secondary amino groups.

[0189] Octylamine: An organic compound containing a primary amino group.

[0190] <Hardening Accelerator>

[0191] Bis(dimethylaminomethyl)phenol: an organic component with a tertiary amino group.

[0192] <Preparation of Curable Resin Compositions>

[0193] [Example 1]

[0194] The curable resin composition of Example 1 was prepared by stirring and degassing 10 parts of jER828 as liquid epoxy resin (A), 6.4 parts of polyurethane urea resin (B-1) obtained in Manufacturing Example 1, 2.7 parts of D-400 as liquid polyamine (C), 0.5 parts of TETA, 0.3 parts of 3,5-dimethylpyrazole as heterocyclic aromatic compound (D), and 1.1 parts of bis(dimethylaminomethyl)phenol as curing accelerator at room temperature.

[0195] [Examples 2-13, Examples 15-26, and Comparative Examples 1-8]

[0196] Except for changing the formulation to that shown in Tables 2 to 4, the same operations as in Example 1 were performed to prepare the curable resin compositions of Examples 2 to 13, Examples 15 to 26 and Comparative Examples 1 to 8.

[0197] [Example 14]

[0198] The curable resin composition of Example 14 was prepared by stirring and degassing at room temperature with 10 parts of jER828 as liquid epoxy resin (C), 6.1 parts of a mixture of polyurethane urea resin (B-4) obtained in Manufacturing Example 4 (4.3 parts of polyurethane urea resin (B-4) and 1.8 parts of D-230), 0.4 parts of TETA, 0.2 parts of 3,5-dimethylpyrazole as heterocyclic aromatic compound (D), and 0.7 parts of bis(dimethylaminomethyl)phenol as curing accelerator.

[0199] [Table 2]

[0200] Table 2

[0201]

[0202] [Table 3]

[0203] Table 3

[0204]

[0205] [Table 4]

[0206] Table 4

[0207]

[0208] <Evaluation of Curable Resin Compositions>

[0209] The following tests were performed on the curable resin compositions prepared in the Examples and Comparative Examples. The results are recorded in Tables 2 to 4.

[0210] [Adhesiveness and Coagulation Destructive Properties]

[0211] Each curable resin composition was coated onto an aluminum substrate (100 mm long, 25 mm wide, and 2 mm thick) in a manner with a length of 10 mm, a width of 25 mm, and a thickness of 0.2 mm. The substrate was then bonded to the same aluminum substrate and cured at 25°C for 7 days while maintaining a thickness of 0.2 mm. Test pieces for adhesiveness and cohesion destructiveness were obtained. The shear bond strength of the obtained test pieces was measured using a tensile testing machine at a temperature of 25°C and a relative humidity of 50% at a tensile speed of 50 mm / min. Adhesiveness was determined according to the following evaluation criteria. Furthermore, the cohesion destructiveness of the test pieces after the shear bond strength measurement was visually confirmed, and the cohesion destructiveness was determined according to the following evaluation criteria.

[0212] (Adhesion evaluation criteria)

[0213] ◎: Shear bond strength is above 17 MPa (Good)

[0214] ○: Shear bond strength of 10 MPa or higher and less than 17 MPa (suitable for use)

[0215] ×: Shear bond strength less than 10 MPa (cannot be used)

[0216] (Agglomeration destructive assessment benchmark)

[0217] ◎: Relative to the total area of ​​the test piece, over 90% showed coagulation failure (good).

[0218] ○: Relative to the total area of ​​the test piece, 50% to less than 90% indicates cohesion failure (suitable for use).

[0219] ×: If the area is less than 50% relative to the total area of ​​the test piece, it indicates cohesion failure (unusable).

[0220] [Softness]

[0221] The resin composition adhesives were filled into a sheet mold with a thickness of 1 mm, the surface was smoothed, and after curing at 25°C for 7 days, dumbbell-shaped test pieces were made by punching using a No. 3 dumbbell die for evaluating flexibility. The obtained test pieces were tested at 25°C and 50% relative humidity using a tensile testing machine at a tensile speed of 10 mm / min to determine the elongation at break.

[0222] (Evaluation Criteria)

[0223] ◎: Elongation at break is above 120% (Good)

[0224] ○: Elongation at break is 70% or more but less than 120% (suitable for use)

[0225] ×: Elongation at break less than 70% (cannot be used)

[0226] <Overall Evaluation>

[0227] The curable resin compositions prepared in the examples and comparative examples were comprehensively evaluated according to the following criteria. The evaluation results are recorded in Tables 2 to 4.

[0228] (Comprehensive evaluation criteria)

[0229] ◎: Graded ◎ (Good) out of all evaluation items.

[0230] ○: Determines whether there is an × or a ○. (Can be used)

[0231] ×: An × indicates a negative result in any evaluation item. (Cannot be used)

[0232] The curable resin composition of the present invention achieves good results in any one of the aspects of adhesion, coagulation destructiveness, and flexibility. On the other hand, the curable resin compositions of the comparative examples show some or all of the results being worse than those of the examples in terms of adhesion, coagulation destructiveness, and flexibility.

Claims

1. A curable resin composition, which is a solvent-free curable resin composition, characterized in that... It contains a main agent (X) comprising liquid epoxy resin (A) and a curing agent (Y). And satisfy all of the following conditions (i) to (iv): (i) The curing agent (Y) comprises polyurethane urea resin (B), liquid polyamine (C) and heterocyclic aromatic compound (D); (ii) The polyurethane urea resin (B) has a primary amino group or a secondary amino group at the end; (iii) A heterocyclic aromatic compound (D) has two or more adjacent nitrogen atoms in its ring structure, wherein the nitrogen atoms are not substituents; (iv) Of the total 100% by mass of organic components having primary amino groups and organic components having secondary amino groups contained in the curing agent (Y), 10% to 80% by mass of polyurethane urea resin (B) is included.

2. The curable resin composition according to claim 1, wherein, The molecular weight of the liquid polyamine (C) is less than 600.

3. The curable resin composition according to claim 1, wherein, The polyurethane urea resin (B) has an average molecular weight of 1,000 or more and less than 50,000.

4. The curable resin composition according to claim 1, wherein, Of the total 100% by mass of the polyurethane urea resin (B), liquid polyamine (C), and heterocyclic aromatic compound (D), 0.3% to 7.0% by mass of heterocyclic aromatic compound (D) is contained.

5. A hardened compound comprising the hardening resin composition according to any one of claims 1 to 4.

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