Epoxy resin composition and cured product

Abstract

The present invention provides an epoxy resin composition having excellent adhesion to dissimilar materials. The epoxy resin composition of the present invention contains (A) to (E) below: (A) a compound that is liquid at 25°C, has two or more epoxy groups in one molecule, and has an epoxy equivalent weight of less than 210 g / eq, (B) (B-1) a compound that is liquid at 25°C, has two or more epoxy groups in one molecule, and has an epoxy equivalent weight of 210 g / eq or more and / or (B-2) a compound that is solid at 25°C and has two or more epoxy groups in one molecule, (C) a thiol curing agent, (D) a latent curing agent, and (E) a reactive diluent.

Description

Technical Field

[0001] This invention relates to epoxy resin compositions that exhibit excellent adhesion to dissimilar materials and their cured products. Background Technology

[0002] In recent years, the diversification of components has been continuously increasing, requiring adhesives that can bond dissimilar materials with different coefficients of linear expansion. Among these, epoxy resins exhibit good adhesion, excellent chemical resistance, and durability, making them widely used and suitable for bonding dissimilar materials. As an example of such epoxy resins, Japanese Patent Application Publication No. 2019-156965 discloses an epoxy resin composition containing (A) a thiol-based curing agent, (B) a multifunctional epoxy resin, and (C) a monofunctional epoxy resin crosslinking density modifier, wherein the number (amount) of thiol groups and epoxy groups in these components have a specific relationship.

[0003] However, conventional adhesives (epoxy resins) for bonding dissimilar materials have insufficient adhesion to such materials, requiring further improvement in adhesion. Furthermore, conventional adhesives (epoxy resins) suffer from high curing temperatures, high viscosity, and poor workability. Moreover, if the viscosity of conventional adhesives (epoxy resins) is reduced to improve workability, the curing shrinkage is large, causing deformation of the bonded components during curing. Summary of the Invention

[0004] The present invention was made in view of the above-mentioned situation, and its object is to provide an epoxy resin composition with excellent adhesion to dissimilar materials. Another object of the present invention is to provide an epoxy resin composition that, in addition to excellent adhesion to dissimilar materials, also exhibits good workability, low-temperature curing properties, low viscosity, and consequently low curing shrinkage. Furthermore, a further object of the present invention is to provide a cured product obtained by curing the above-mentioned epoxy resin composition.

[0005] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that the epoxy resin composition described in the following detailed description has excellent adhesion to dissimilar materials, thus completing the present invention.

[0006] The following describes the essence of the present invention.

[0007] [1] An epoxy resin composition comprising the following components (A) to (E):

[0008] (A) A compound that is liquid at 25°C, has more than two epoxy groups per molecule, and has an epoxy equivalent of less than 210 g / eq.

[0009] (B)(B-1) Compounds that are liquid at 25°C, have two or more epoxy groups per molecule and an epoxy equivalent of 210 g / eq or more, and / or (B-2) Compounds that are solid at 25°C and have two or more epoxy groups per molecule.

[0010] (C) Thiol curing agent

[0011] (D) Latent curing agent

[0012] (E) Reactive diluent.

[0013] [2] As far as the epoxy resin composition described in [1] is concerned, the above-mentioned component (A) is a bisphenol type epoxy resin.

[0014] [3] With respect to the epoxy resin composition described in [1] or [2], the content of component (B) is 1 to 100 parts by mass relative to 100 parts by mass of component (A).

[0015] [4] With regard to any of the epoxy resin compositions described in [1] to [3], the above-mentioned component (B) is a bisphenol type epoxy resin and / or a biphenyl type epoxy resin.

[0016] [5] With regard to any of the epoxy resin compositions described in [1] to [4], the above-mentioned component (C) is a compound having three or more SH groups.

[0017] [6] For any of the epoxy resin compositions described in [1] to [5], the content of component (C) is 50 to 300 parts by mass relative to 100 parts by mass of component (A).

[0018] [7] The epoxy resin composition described in any one of [1] to [6] further contains (F) an inorganic filler.

[0019] [8] For any of the epoxy resin compositions described in [1] to [7], the curing shrinkage rate is 5% or less.

[0020] [9] With respect to any of the epoxy resin compositions described in [1] to [8], for bonding and / or sealing between substrates with different coefficients of linear expansion.

[0021]

[10] A cured product of an epoxy resin composition described in any one of [1] to [9]. Detailed Implementation

[0022] The following describes embodiments of the present invention. It should be noted that the present invention is not limited to the following embodiments. It should be noted that in this specification, "X to Y" refers to the values ​​(X and Y) listed before and after it as a lower limit and an upper limit, meaning "above X and below Y". Furthermore, unless otherwise specified, concentration and % respectively represent mass concentration and mass percentage, and unless otherwise specified, ratio represents mass ratio. Furthermore, unless otherwise specified, operations and measurements of physical properties are performed at room temperature (20-25°C) and relative humidity 40-55% RH. Furthermore, "A and / or B" refers to each of A and B, and combinations thereof.

[0023] [Epoxy Resin Composition]

[0024] An epoxy resin composition (hereinafter referred to as "epoxy resin composition" or simply "resin composition") according to one aspect of the present invention contains the following components (A) to (E):

[0025] (A) A compound that is liquid at 25°C, has more than two epoxy groups per molecule, and has an epoxy equivalent of less than 210 g / eq.

[0026] (B)(B-1) Compounds that are liquid at 25°C, have two or more epoxy groups per molecule and an epoxy equivalent of 210 g / eq or more, and / or (B-2) Compounds that are solid at 25°C and have two or more epoxy groups per molecule.

[0027] (C) Thiol curing agent

[0028] (D) Latent curing agent

[0029] (E) Reactive diluent.

[0030] One aspect of the present invention relates to an epoxy resin composition that exhibits excellent adhesion to dissimilar materials. Furthermore, in addition to its excellent adhesion to dissimilar materials, the epoxy resin composition of one aspect of the present invention possesses low-temperature curing properties for good workability and low viscosity, resulting in low curing shrinkage, making it highly useful.

[0031] The detailed mechanism is not yet clear. The epoxy resin composition of the present invention contains, together with component (A), component (B), which has a higher molecular weight (higher epoxy equivalent) than component (A). Therefore, it is believed that it has an effect of improving the adhesion to dissimilar materials. On the other hand, when the epoxy resin composition does not contain a compound equivalent to component (B), the adhesion to dissimilar materials decreases (Comparative Example 1 described later).

[0032] It should be noted that the above mechanism is based on speculation, and whether the mechanism is correct or not has no impact on the technical scope of the present invention.

[0033] <(A)Component>

[0034] The (A) component contained in the epoxy resin involved in this invention is a compound that is liquid at 25°C, has two or more epoxy groups in one molecule, and has an epoxy equivalent of less than 210 g / eq.

[0035] In this specification, "liquid at 25°C" means a state that is fluid at 25°C. Specifically, "liquid at 25°C" means satisfying at least one of (i) and (ii) below;

[0036] (i) At 25°C, the viscosity measured using a cone-plate rotational viscometer is below 100 Pa·s;

[0037] (ii) The softening point or melting point (in the case of both softening point and melting point) is below 35°C.

[0038] It should be noted that the softening point mentioned above was determined using the method based on JIS K 7234:1986 (ring and ball method). Additionally, the melting point mentioned above was determined using differential scanning calorimetry (DSC).

[0039] Furthermore, in this specification, the epoxy equivalent is a value determined based on JIS K 7236:2001. Alternatively, if the epoxy equivalent cannot be determined by this method, it can be calculated by dividing the molecular weight of the epoxy resin in question by the number of epoxy groups contained in one molecule of that epoxy resin.

[0040] Regarding the epoxy equivalent of component (A), from the viewpoint of enabling it to exhibit low-temperature curing properties and reducing curing shrinkage, it is preferable to have 50 g / eq or more and less than 210 g / eq, more preferably 100 g / eq or more and less than 210 g / eq, and particularly preferably 130 g / eq or more and less than 180 g / eq.

[0041] Furthermore, from the viewpoint of reducing the viscosity of the obtained epoxy resin composition, the viscosity of component (A) is preferably 0.01 Pa·s or more and less than 100 Pa·s at 25°C, more preferably 0.1 Pa·s to 70 Pa·s, even more preferably 0.1 to 50 Pa·s, even more preferably 0.3 to 10 Pa·s, and most preferably 0.5 to 5 Pa·s.

[0042] In addition, the softening point or melting point of component (A) (where both softening point and melting point are present, it is the softening point) is preferably 10°C or higher and 35°C or lower, more preferably 15°C or higher and 30°C or lower.

[0043] Regarding the compound of component (A), there is no particular limitation as long as the number of epoxy groups contained in one molecule is two or more, but it is preferred to have 2 to 6 (2 to 6 functional epoxy resin), more preferably 2 to 3 (2 to 3 functional epoxy resin), and particularly preferred to have 2 (2 functional epoxy resin).

[0044] Specific examples of compounds that can be used as component (A) include bisphenol-type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD ​​type epoxy resin, bisphenol AF type epoxy resin, and hydrogenated bisphenol type epoxy resin; phenolic varnish type epoxy resin; glycidylamine type epoxy resin; dimer acid modified epoxy resin; alicyclic epoxy resin, etc., but are not limited to these. One of these can be used alone, or two or more can be used in combination. From the viewpoint of reducing curing shrinkage, component (A) is preferably a bisphenol-type epoxy resin. Furthermore, from the same viewpoint as above, component (A) is more preferably composed of at least one selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AF type epoxy resin, and particularly preferably includes both bisphenol A type epoxy resin and bisphenol F type epoxy resin.

[0045] The compound (epoxy resin) used as component (A) can be either synthetic or commercially available.

[0046] Commercially available products containing ingredient (A) include, for example, JER (registered trademark) 825, 827, 828, 828EL, 828XA, 828US, 806, 806H, 807, 152, 871, 872, YL980, YL983U, YX8000, YX8034 (manufactured by Mitsubishi Chemical Corporation), and EPICLON (registered trademark) 840, 840S, 850, 850S, 850CRP, 850-LC, 830, 835, and EXA-830L. VP, EXA-830LVP, EXA-835LV, N-730A (manufactured by DIC Corporation), Denacol (registered trademark) EP-4100, EP-4100G, EP-4100E, EP-4300E, EP-4530, EP-4901, EP-4901E (manufactured by ADEKA Corporation), EX-810, EX-811, EX-850, EX-821, EXA-920, EX-201, EX-212 (manufactured by Nagase ChemteX Corporation), etc., but not limited to these.

[0047] The compound (epoxy resin) used as component (A) above can be used alone or in combination with two or more. It should be noted that when two or more are used in combination, the content of component (A) refers to the total amount.

[0048] [(B) Component]

[0049] The epoxy resin involved in this invention contains component (B), which includes components (B-1) and / or (B-2):

[0050] (B-1) Composition: A compound that is liquid at 25°C, has more than two epoxy groups per molecule and has an epoxy equivalent of 210 g / eq or more.

[0051] (B-2) Composition: A compound that is solid at 25°C and has more than two epoxy groups per molecule.

[0052] Component (B), when combined with component (A) above, can improve adhesion to dissimilar materials while maintaining low curing shrinkage.

[0053] It should be noted that the statement that the compound is "liquid at 25°C" is based on the definition described in the description of component (A) above. Furthermore, the epoxy equivalent of the compound was also determined using the method described in the description of component (A) above.

[0054] In this specification, "solid at 25°C" means a state in which it is not fluid at 25°C. Specifically, "solid at 25°C" means that it satisfies at least one of (i') and (ii') below;

[0055] (i') The viscosity measured at 25°C using a cone-plate rotational viscometer exceeds 100 Pa·s;

[0056] (ii') The softening point or melting point (in the case of both a softening point and a melting point, the softening point) is 35°C or higher. It should be noted that the method for determining the softening point and melting point shall be as described in the description of component (A) above.

[0057] The epoxy equivalent of component (B-1) is preferably 210–1000 g / eq, more preferably 230–700 g / eq, even more preferably 230–500 g / eq, and most preferably 230–300 g / eq. As long as the epoxy equivalent of component (B-1) is 210 g / eq or higher, and further 230 g / eq or higher, the adhesion to dissimilar materials can be improved while maintaining low curing shrinkage. Furthermore, as long as the epoxy equivalent of component (B-1) is 1000 g / eq or lower, a low-viscosity epoxy resin composition with excellent workability can be obtained.

[0058] Furthermore, from the viewpoint of reducing the viscosity of the obtained epoxy resin composition, the viscosity of component (B-1) is preferably 0.01 Pa·s or more and less than 100 Pa·s at 25°C, more preferably 0.1 Pa·s to 70 Pa·s, even more preferably 0.1 to 50 Pa·s, even more preferably 0.3 to 10 Pa·s, and particularly preferably 0.5 to 5 Pa·s.

[0059] In addition, the softening point or melting point of component (B-1) (where both softening point and melting point are present, it is the softening point) is preferably 10°C or higher and lower than 35°C, more preferably higher than 25°C and lower than 35°C.

[0060] There are no particular limitations on the epoxy equivalent of component (B-2), but it is preferably 100 to 3000 g / eq, more preferably 130 to 2000 g / eq, even more preferably 150 to 1000 g / eq, and most preferably 230 to 800 g / eq. As long as the epoxy equivalent of component (B-2) is 100 g / eq or more, and further 230 g / eq or more, the adhesion to dissimilar materials can be improved while maintaining low curing shrinkage. In addition, as long as the epoxy equivalent of component (B-2) is 3000 g / eq or less, and further 800 g / eq or less, an epoxy resin composition with low viscosity and excellent workability can be obtained.

[0061] The softening point or melting point of component (B-2) (where both a softening point and a melting point are present, the softening point is the preferred value) is 40–200°C, more preferably 50–150°C, even more preferably 55–130°C, and most preferably 60–100°C. As long as the softening point or melting point of component (B-2) is 40–200°C, an epoxy resin composition with good compatibility with component (A) and low viscosity can be obtained.

[0062] Regarding the compounds of component (B) (components (B-1) and (B-2)), there are no particular limitations as long as the number of epoxy groups contained in one molecule is two or more, but two to six (2 to 6 functional epoxy resins) are preferred, two to three (2 to 3 functional epoxy resins) are more preferred, and two (2 functional epoxy resins) are particularly preferred. By making the number of epoxy groups within the above range, the adhesion to dissimilar materials can be improved while maintaining low curing shrinkage.

[0063] Specific examples of component (B) (components (B-1) and (B-2)) include bisphenol-type epoxy resin, naphthalene-type epoxy resin, dicyclopentadiene-type epoxy resin, phenolic varnish resin, cresol varnish resin, biphenyl-type epoxy resin, etc., but are not limited to these. One of these can be used alone, or two or more can be used in combination. From the viewpoint of reducing curing shrinkage, component (B) is preferably a bisphenol-type epoxy resin and / or a biphenyl-type epoxy resin. Furthermore, from the same viewpoint, component (B) preferably contains at least one selected from the group consisting of bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and biphenyl-type epoxy resin.

[0064] Furthermore, from the viewpoint of obtaining an epoxy resin composition with low viscosity and excellent low-temperature curing properties, component (B) preferably contains (B-1). And from the same viewpoint, component (B) preferably contains only component (B-1) (i.e., component (B) is component (B-1)).

[0065] The compound (epoxy resin) used as component (B) can be either synthetic or commercially available.

[0066] Commercially available products that are ingredients (B) include, but are not limited to, jER (registered trademark) 834, 1001, 1002, 1003, 1055, 1004, 1004AF, 4005P, 4007P, YX4000H (manufactured by Mitsubishi Chemical Corporation), EPICLON (registered trademark) 860, 1050, 1055, 2050, 3050, 4050, 7050, HM-091, HP-7200L, HP-7200, HP-7200H, HP-4700, and HP-4770 (manufactured by DIC Corporation).

[0067] The compound (epoxy resin) used as component (B) above can be used alone or in combination with two or more. It should be noted that when two or more are used in combination, the content of component (B) refers to the total amount.

[0068] Regarding the content of component (B), it is preferably 1 to 100 parts by mass relative to 100 parts by mass of component (A), more preferably 5 to 100 parts by mass, even more preferably 10 to 80 parts by mass, even more preferably 15 to 70 parts by mass, and most preferably 20 to 50 parts by mass. As long as the content of component (B) is 1 part by mass or more, and further 5 parts by mass or more, the adhesion to dissimilar materials can be improved while maintaining low curing shrinkage. Furthermore, as long as the content of component (B) is 100 parts by mass or less, an epoxy resin composition with low viscosity and excellent workability can be obtained.

[0069] [(C) Component]

[0070] The (C) component contained in the epoxy resin of the present invention is a thiol curing agent. As for the thiol curing agent as component (C), there is no particular limitation as long as one molecule contains one or more thiol groups (SH groups). From the viewpoint of obtaining an epoxy resin composition with excellent low-temperature curing properties, the thiol curing agent is preferably a compound having two or more SH groups, more preferably a compound having three or more, and most preferably a compound having four or more. On the other hand, there is no particular upper limit on the number of SH groups, but from the viewpoint of obtaining an epoxy resin composition with low viscosity and excellent workability, it is 10 or less.

[0071] From the viewpoint of low-temperature curing properties, there is no particular limitation on the thiol equivalent of component (C), but 50–500 g / eq (g / mol) is preferred, more preferably 70–300 g / eq (g / mol), even more preferably 90–200 g / eq (g / mol), and most preferably 110–150 g / eq (g / mol). It should be noted that the thiol equivalent can be determined by iodine titration. Alternatively, if the thiol equivalent cannot be determined by this method, it can be calculated by dividing the molecular weight of the desired thiol curing agent by the number of SH groups contained in one molecule of that thiol curing agent.

[0072] The substitution position of the SH group in the thiol curing agent (component C) is not particularly limited; it can exist at the end of the compound or as a side chain. In other words, the SH group in the thiol curing agent (component C) can be any of primary thiol, secondary thiol, or tertiary thiol groups. From the viewpoint of reducing the curing shrinkage of the epoxy resin composition, primary thiol or secondary thiol groups are preferred, and secondary thiol groups are more preferred. That is, from the viewpoint of reducing the curing shrinkage of the epoxy resin composition, the thiol curing agent (component C) is preferably a primary thiol compound or a secondary thiol compound, and secondary thiol compounds are more preferred. It should be noted that a primary thiol group indicates that the carbon bonded to the sulfur atom (the carbon bonded to the SH group) is a primary carbon atom; similarly, a secondary thiol group indicates that the carbon bonded to the sulfur atom (the carbon bonded to the SH group) is a secondary carbon atom, and a tertiary thiol group indicates that the carbon bonded to the sulfur atom (the carbon bonded to the SH group) is a tertiary carbon atom.

[0073] Specific examples of component (C) include primary thiols such as trimethylolpropane tris(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetra(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), and dipentaerythritol hexa(3-mercaptopropionate); secondary thiols such as pentaerythritol tetra(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptobutyrate), trimethylolethane tris(3-mercaptobutyrate), trimethylolpropane tris(3-mercaptobutyrate), and trimethylolethane tris(3-mercaptobutyrate); etc., but not limited to these. These can be used individually or in combination with two or more.

[0074] The thiol curing agent used as component (C) can be either synthetic or commercially available.

[0075] Commercially available products that are ingredients (C) include, but are not limited to, TMMP, TEMPIC, PEMP, EGMP-4, DPMP manufactured by SC Organic Chemicals Co., Ltd., and Karenz MT (registered trademark) PE1, BD1, NR1, TPMB manufactured by Showa Denko Co., Ltd.

[0076] The thiol curing agent used as component (C) above can be used alone or in combination with two or more. It should be noted that when two or more are used in combination, the content of component (C) refers to the total amount.

[0077] Regarding the content of component (C), it is preferably 50 to 300 parts by mass relative to 100 parts by mass of component (A), more preferably 130 to 250 parts by mass, and most preferably 150 to 230 parts by mass. As long as the content of component (C) is 50 parts by mass or more, an epoxy resin composition with excellent low-temperature curing properties and adhesion can be obtained. Furthermore, as long as the content of component (C) is 300 parts by mass or less, good adhesive strength can be maintained.

[0078] Furthermore, regarding the content of component (C), it is preferably 50 to 300 parts by mass relative to the total of 100 parts by mass of components (A) and (B), more preferably 70 to 200 parts by mass, even more preferably 100 to 170 parts by mass, and most preferably 135 to 160 parts by mass. As long as the content of component (C) is 50 parts by mass or more, an epoxy resin composition with excellent low-temperature curing properties and adhesion can be obtained. Furthermore, as long as the content of component (C) is 300 parts by mass or less, good adhesive strength can be maintained.

[0079] The functional group equivalent ratio of component (A) and component (B) relative to component (C) ({functional group equivalent of component (A) + functional group equivalent of component (B)} / functional group equivalent of component (C)) is preferably 0.1 to 2.0, more preferably 0.2 to 1.5, even more preferably 0.3 to 1.0, and most preferably 0.40 to 0.60. If the above functional group equivalent ratio is 0.1 to 2.0, the curability of the epoxy resin composition can be well maintained. It should be noted that the above functional group equivalent ratio is a value obtained by calculating the ratio of the content (compound amount) of each component to the epoxy equivalent or SH equivalent ({(A) + (B))} / (C)).

[0080] The method for determining the above functional group equivalence ratio is explained in detail below:

[0081] First, for components (A) and (B), calculate the epoxy functional group equivalent, i.e., the total number of epoxy groups contained in each component. Specifically, calculate the value obtained by dividing the mass (g) of epoxy resin contained in components (A) and (B) by the epoxy equivalent of the epoxy resin. Similarly, for component (C), calculate the thiol functional group equivalent, i.e., the total number of SH groups contained in component (C). Specifically, calculate the value obtained by dividing the mass (g) of thiol compounds contained in component (C) by the thiol (SH) equivalent of the thiol compounds. It should be noted that when a component contains multiple epoxy resins or thiol compounds, calculate the above value (functional group equivalent) for each epoxy resin or thiol compound separately, and average their weights as the epoxy functional group equivalent or thiol functional group equivalent of each component.

[0082] Next, by dividing the sum of the epoxy functional group equivalents of components (A) and (B) obtained as described above by the thiol functional group equivalent of component (C), the functional group equivalent ratio of components (A) and (B) relative to component (C) can be determined.

[0083] [(D) component]

[0084] The epoxy resin involved in this invention contains component (D), which is a latent curing agent. Here, a latent curing agent refers to a curing agent that can maintain stability over time, such as minimal changes in viscosity and physical properties, while remaining dispersed in components (A) and (B).

[0085] As for component (D), there are no particular restrictions as long as it is a latent curing agent as described above, but it is a component that promotes curing based on component (C), and compounds with thermosetting properties are particularly preferred.

[0086] Furthermore, as component (D), compounds having an imidazole skeleton are preferred; epoxy adduct compounds (reaction products of epoxy compounds and tertiary amine compounds, etc.) obtained by adding tertiary amine compounds to epoxy resins and stopping the reaction midway are also preferred; and fine powders obtained by pulverizing these compounds are even more preferred. From the viewpoint of maintaining low-temperature curing properties and reducing curing shrinkage, component (D) is preferably a modified aliphatic polyamine adduct or a modified alicyclic polyamine adduct, and particularly preferably a modified aliphatic polyamine adduct.

[0087] When component (D) is a compound with an imidazole skeleton or an epoxy addition compound, its amine value is preferably 50 to 300, more preferably 70 to 200, and most preferably 80 to 150. As long as the above-mentioned amine value is 50 to 300, the storage stability and low-temperature curing properties of the obtained epoxy resin composition can be well maintained. It should be noted that the amine value refers to the mass (mg) of potassium hydroxide (KOH) equivalent to the amount of hydrochloric acid necessary to neutralize the primary, secondary, and tertiary amines contained in 1g of the epoxy addition compound. The amine value can be determined according to ASTM D2074.

[0088] From the viewpoint of improving curability (increasing curing speed) and ensuring good storage stability, component (D) is preferably a substance that is solid at 25°C. Furthermore, from the same viewpoint, regarding the softening point of component (D), from the perspective of low-temperature curing and storage stability, it is preferably 70–300°C, more preferably 90–200°C, and most preferably 100–130°C.

[0089] The average particle size of component (D) is preferably 0.1–50 μm, more preferably 1–30 μm, even more preferably 2–20 μm, and most preferably 5–10 μm. If the average particle size is 0.1–50 μm, the dispersibility when components (A) and (B) are mixed becomes good, and an epoxy resin composition exhibiting stable low-temperature curing properties can be obtained. It should be noted that methods for determining the average particle size include laser diffraction scattering type, particle size and shape distribution measuring instruments with differential sorting control, optical microscopes, electron microscopes, and image analysis.

[0090] As a latent curing agent for component (D), either synthetic or commercially available products can be used.

[0091] Commercially available products that are ingredients (D) include, but are not limited to, Amicure (registered trademark) PN-23, PN-23J, PN-31, PN-31J, PN-40J, PN-H, PN-R, MY-24, MY-R (manufactured by Ajinomoto Fine-Techno Co., Ltd.), Fujicure (registered trademark) FXE-1000, FXR-1030, FXR-1081 (manufactured by T&K Toka Co., Ltd.), Curezol (registered trademark) SIZ, 2MZ-H, C11Z, C17Z, 2PZ, 2PZ-PW, 2P4MZ (manufactured by Shikoku Chemical Industry Co., Ltd.).

[0092] As a latent curing agent for component (D) above, one type can be used alone, or two or more types can be used in combination. It should be noted that when two or more types are used in combination, the content of component (D) refers to the total amount.

[0093] Regarding the content of component (D), it is preferably 0.001 to 30 parts by mass relative to 100 parts by mass of component (C), more preferably 0.01 to 20 parts by mass, even more preferably 0.01 to 17 parts by mass, and most preferably 5 to 16 parts by mass. As long as the content of component (D) is 0.001 to 30 parts by mass, the low-temperature curing property can be maintained while maintaining good storage stability of the epoxy resin composition.

[0094] [(E) component]

[0095] The (E) component contained in the epoxy resin involved in this invention is a reactive diluent. Here, a reactive diluent refers to a compound that, while functioning as a solvent, also possesses groups that react with components (A) to (D).

[0096] As for component (E), there are no particular restrictions as long as it is a reactive diluent as described above, but from the viewpoint of reducing the viscosity of the epoxy resin composition, a compound having one epoxy group in one molecule is preferred.

[0097] From the viewpoint of reducing the viscosity of the obtained epoxy resin composition, the viscosity of component (E) is preferably 1 to 1000 mPa·s, more preferably 1 to 700 mPa·s, even more preferably 1 to 500 mPa·s, and most preferably 10 to 100 mPa·s.

[0098] The epoxy equivalent of component (E) is preferably 100–500 g / eq, more preferably 150–300 g / eq, and most preferably 170–250 g / eq. As long as the epoxy equivalent is 100–500 g / eq, an epoxy resin composition with good curability, low viscosity, and excellent curing shrinkage can be obtained.

[0099] Specific examples of ingredient (E) include phenyl glycidyl ether, o-tolyl glycidyl ether, p-tert-butylphenyl glycidyl ether, 2-ethylhexyl glycidyl ether, butyl glycidyl ether, C12-C14 alcohol glycidyl ether, butane diglycidyl ether, hexane diglycidyl ether, cyclohexane dimethyl diglycidyl ether, neodecanoic acid glycidyl ester, or glycidyl ethers with polyethylene glycol or polypropylene glycol as the main backbone, but are not limited to these. Furthermore, these can be used alone or in combination of two or more. It should be noted that when two or more are used together, the content of ingredient (E) refers to the total amount.

[0100] From the perspective of improving adhesion to dissimilar materials while maintaining low curing shrinkage, component (E) preferably contains p-tert-butylphenyl glycidyl ether.

[0101] Furthermore, regarding the content of component (E), it is preferably 10 to 300 parts by mass relative to a total of 100 parts by mass of (A) and (B), more preferably 20 to 200 parts by mass, even more preferably 50 to 120 parts by mass, and most preferably 60 to 100 parts by mass. As long as the content of the above-mentioned component (E) is 10 to 300 parts by mass, an epoxy resin composition with low viscosity while maintaining good adhesive strength can be obtained.

[0102] [(F)INGREDIENT]

[0103] The epoxy resin composition of the present invention may further contain an inorganic filler as component (F) in addition to components (A) to (E) mentioned above.

[0104] As component (F), known materials used as inorganic fillers can be used. Specific examples of component (F) include, but are not limited to, alumina powder, calcium carbonate powder, talc powder, silica powder, calcined silica powder, silver powder, nickel powder, palladium powder, carbon powder, tungsten powder, and electroplating powder. These can be used alone or in combination of two or more. It should be noted that when two or more are used together, the content of component (E) refers to the total amount.

[0105] From the viewpoint of improving adhesive strength, component (F) preferably contains silica powder or calcined silica powder, more preferably contains silica powder, and particularly preferably contains spherical silica powder.

[0106] The average particle size of component (F) is preferably 0.01–50 μm, more preferably 0.1–30 μm, and particularly preferably 0.1–5 μm. As long as the average particle size is 0.01–50 μm, the viscosity increase of the obtained epoxy resin composition can be effectively suppressed.

[0107] Regarding the content of component (F), it is preferably 1 to 300 parts by mass relative to the total of 100 parts by mass of components (A) and (B), more preferably 30 to 200 parts by mass, and most preferably 50 to 150 parts by mass. If the content of component (F) is 1 to 300 parts by mass, the adhesive strength can be improved while suppressing the increase in viscosity of the obtained epoxy resin composition.

[0108] [Any ingredients]

[0109] Regarding the epoxy resin involved in this invention, without impairing the characteristics of this invention, in addition to the components (A) to (E) described above, it may further contain additives such as organic fillers (excluding components (A) to (E)), pigments, dyes, silane coupling agents, leveling agents, rheology modifiers, and preservation stabilizers as any component.

[0110] As the aforementioned organic fillers, powders of organic materials composed of rubber, elastomers, plastics, polymers (or copolymers), etc. (excluding components (A) to (E)) can be used. Additionally, organic fillers with multi-layered structures, such as core-shell type, can also be used as organic fillers. One of these can be used alone, or two or more can be used in combination.

[0111] The average particle size of the organic filler is preferably in the range of 0.05 to 50 μm. From the viewpoint of improving durability, fillers composed of polymers of acrylates and / or methacrylates or copolymers thereof, fillers composed of polymers or copolymers of styrene compounds, etc., are preferred as organic fillers. Regarding the appropriate content of the organic filler (the total amount when containing two or more), it is preferably 1 to 50 parts by mass relative to 100 parts by mass of component (A), more preferably 5 to 30 parts by mass.

[0112] Examples of silane coupling agents include 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldipropoxysilane, 3-glycidoxypropyldimethylmonomethoxysilane, 3-glycidoxypropyldimethylmonoethoxysilane, 3-glycidoxypropyldimethylmonopropoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropyl... Silane coupling agents containing glycidyl groups, such as triethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, and 3-epoxypropoxypropylmethyldiethoxysilane; silane coupling agents containing vinyl groups, such as vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, and vinyltrimethoxysilane; and silane coupling agents containing vinyl groups, such as 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, and 3-methacryloyloxypropylmethyldimethoxysilane. Methoxysilane, 3-methacryloxypropyldimethylmonoethoxysilane, 3-acryloxypropylmethyldipropoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldiethoxysilane, 3-acryloxypropylmethyldipropoxysilane, 3-acryloxypropyldimethylmonopropoxysilane, 3-acryloxypropyldimethylmonomethoxysilane, 3-acryloxypropyldimethylmonomethoxysilane, 3-acryloxypropyldimethylmonomethoxysilane Silane coupling agents containing (meth)acryloyl groups, such as methylpropyldimethylmonethoxysilane, 3-acryloyloxypropyldimethylmonethoxysilane, and 3-methacryloyloxypropyltrimethoxysilane; silane coupling agents containing amino groups, such as N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; γ-mercaptopropyltrimethoxysilane; and γ-chloropropyltrimethoxysilane, etc. Among these, silane coupling agents containing glycidyl groups are preferred from the viewpoint of superior adhesion. These can be used alone or in combination of two or more. Regarding the suitable range of the content of the silane coupling agent (the total amount when containing two or more), it is preferably 0.1 to 20 parts by weight relative to 100 parts by weight of component (A).

[0113] As the aforementioned preservation stabilizers, borate esters, phosphoric acid, alkyl phosphate esters, and p-toluenesulfonic acid can be used. Examples of borate esters include tributyl borate, trimethoxyborooxane, and ethyl borate, but are not limited to these. Examples of alkyl phosphate esters include trimethyl phosphate and tributyl phosphate, but are not limited to these. These can be used alone or in combination. Considering the effect on curing shrinkage, the preservation stabilizer is preferably selected from one or more of the group consisting of phosphoric acid, alkyl phosphate esters, borate esters, trimethoxyborooxane, and methyl p-toluenesulfonate, more preferably phosphoric acid or borate esters. From the viewpoint of maintaining low-temperature curing properties and reducing curing shrinkage, the appropriate content of the preservation stabilizer (the total amount when containing two or more) is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of component (A).

[0114] <Method for manufacturing epoxy resin composition>

[0115] The method for manufacturing the epoxy resin composition involved in this invention is not particularly limited and can be carried out by conventionally known methods. For example, predetermined amounts of components (A) to (E), component (F) added as needed, and any other added components (arbitrary components) are weighed and added sequentially or simultaneously to a mixing vessel in any order, and then mixed using a mixing machine or other mixing means to obtain the epoxy resin composition involved in this invention. In this case, the manufacturing conditions are not particularly limited, but the mixing temperature is preferably 10 to 50°C, and the mixing time is preferably 10 minutes to 3 hours.

[0116] <Coating Method>

[0117] As a method for applying the epoxy resin composition of the present invention to the substrate, the same method as known methods for applying sealants and adhesives is used. For example, methods such as dispensing, spraying, inkjet printing, screen printing, gravure printing, dipping, spin coating, etc., using an automatic coating machine can be employed.

[0118] From the viewpoint of coatability, the viscosity (at 25°C) of the epoxy resin composition involved in this invention is preferably 10,000 mPa·s or less, more preferably 5,000 mPa·s or less, even more preferably 2,000 mPa·s or less, particularly preferably 1,500 mPa·s or less, and most preferably 600 mPa·s or less. On the other hand, there is no particular limitation on the lower limit, but it is, for example, 100 mPa·s or more, and further, 200 mPa·s or more.

[0119] <Curing methods and cured products>

[0120] The epoxy resin composition involved in this invention can be cured by heating. Therefore, another aspect of the invention is a cured product (cured epoxy resin composition) obtained by curing the above-mentioned epoxy resin composition.

[0121] One of the features of the epoxy resin composition of the present invention is its low curing shrinkage when cured. Specifically, a curing shrinkage rate of 5% or less is preferred. It should be noted that the above-mentioned curing shrinkage rate is a value obtained by the method described in the examples. When the epoxy resin composition of the present invention is used for applications such as adhesives, a curing shrinkage rate of 4.5% is more preferred for the purpose of suppressing deformation of the adhered material. On the other hand, there is no particular limitation on the lower limit of the above-mentioned curing shrinkage rate, but it is substantially around 0%.

[0122] There are no particular limitations on the method for manufacturing the cured product, and known methods can be used. As an example, a method of applying the epoxy resin composition of the present invention to an adhesive surface and then heating it to cure it can be described. In this case, the thickness of the coating film is not particularly limited and can be appropriately adjusted within the range that allows the adhesive surface to bond. Furthermore, there are no particular limitations on the heating temperature and heating time (curing time), as long as the conditions allow the epoxy resin composition to cure sufficiently. However, as suitable specific examples of heating conditions, the heating temperature is preferably 50°C to 200°C, more preferably 50°C or higher but lower than 200°C, even more preferably 60°C to 150°C, and particularly preferably 70°C to 100°C. Thus, the low curing temperature of the epoxy resin composition of the present invention is also a characteristic. In addition, the curing time is not particularly limited, but for example, 30 seconds to 5 hours is preferred, more preferably 1 minute to 3 hours. As a more specific example of the heating temperature and heating time (curing time), when the temperature is 50°C or higher but lower than 200°C, 1 minute to 3 hours is preferred, more preferably 2 minutes to 2 hours.

[0123] <Object to be adhered>

[0124] The epoxy resin composition of the present invention exhibits excellent adhesion to dissimilar materials and is suitable for bonding and / or sealing between components with different coefficients of linear expansion, such as plastics and metals.

[0125] In this specification, "dissimilar materials" refers to two or more materials that are different from each other; specifically, materials with different coefficients of linear expansion. That is, the epoxy resin composition involved in this invention is preferably used for bonding and / or sealing between adherends with different coefficients of linear expansion.

[0126] There is no particular limitation on the difference in the coefficients of linear expansion between materials with different coefficients of linear expansion, but for example, a difference of 0.1 × 10⁻⁶ is preferred. -6 / K~300×10 -6 / K, more preferably 1×10 -6 / K~200×10 -6 / K, Special Selection

[0127] 5×10-6 / K~100×10 -6 / K.

[0128] It should be noted that in this specification, "the difference in linear expansion coefficients between materials with different linear expansion coefficients" refers to the value obtained by subtracting the linear expansion coefficient of the material with the smaller linear expansion coefficient from the linear expansion coefficient of the material with the larger linear expansion coefficient. Furthermore, regarding the linear expansion coefficient, the coefficients of linear expansion for metallic materials are determined using the method for determining the linear expansion coefficient of each material based on JIS Z 2285:2003, and for plastics, they are determined using the method for determining the linear expansion coefficient of each material based on JIS K 7197:2012.

[0129] Specific examples of bonding dissimilar materials include metals to each other, metals and plastics, metals and rubbers, plastics and rubbers, plastics to each other, and rubbers to each other. Among these, metals to each other, metals and plastics, and plastics to each other are preferred, and metals and plastics are more preferred.

[0130] Examples of metals used as adhesives include iron, stainless steel, copper, nickel, zinc, aluminum, magnesium, gold, silver, and titanium. Examples of plastics used as adhesives include fiber-reinforced plastics (FRP), glass fiber reinforced plastics (GFRP), carbon fiber reinforced plastics (CFRP), polyacrylates, polyesters, polyamides, acrylonitrile-butadiene-styrene copolymers (ABS), 6-nylon, 6,6-nylon, polycarbonate, polyacetal, polyethylene terephthalate, polybutylene terephthalate (PBT), polyphenylene sulfide, polyphenylene ether, polyetheretherketone, polyethylene, and polypropylene. Examples of rubbers used as adhesives include nitrile rubber, polyurethane rubber, silicone rubber, and EPDM. More detailed examples of bonding and / or sealing between dissimilar materials include bonding at least two or more adhesives selected from these materials to each other.

[0131] In addition, the materials (each object to be adhered to) mentioned above can be pre-treated or left untreated.

[0132] <Application>

[0133] The epoxy resin compositions involved in this invention can be used for a variety of applications. Specific examples of applications include: in the automotive field, they can be used for bonding, sealing, casting, and coating of automotive switch parts, headlights, engine internals, electrical components, drive engines, brake fluid tanks, hoods, fenders, body panels such as doors, and windows; in the field of electronic materials, they can be used for bonding, sealing, casting, and coating of flat panel displays (liquid crystal displays, organic EL displays, light-emitting diode displays, field emission displays), video discs, CDs, DVDs, MDs, pickup lenses, and hard disks; and in the battery field, they can be used in lithium batteries, lithium-ion batteries, manganese batteries, alkaline batteries, and fuel cells. This invention relates to the bonding, sealing, and coating of various solar cells, including silicon-based solar cells, pigment-sensitized solar cells, and organic solar cells. In the field of optical components, it can be used for bonding, sealing, and coating of optical fiber materials, passive optical components, optical circuit components, and optoelectronic integrated circuits around optical switches and connectors. In the field of optical equipment, it can be used for bonding, sealing, and coating of camera modules, lens materials, viewfinder prisms, target prisms, viewfinder covers, light-receiving sensors, photographic lenses, and projection lenses for projection televisions. In the field of infrastructure, it can be used for bonding, lining materials, sealing, and coating materials for gas pipes and water pipes. The epoxy resin composition involved in this invention has low viscosity, allowing for small-scale coating and making it suitable for micro-components.

[0134] Example

[0135] The invention will then be described in more detail by way of examples, but the invention is not limited to these examples. Unless otherwise specified, the tests were conducted at 25°C and 55% RH.

[0136] <Preparation of Epoxy Resin Compositions>

[0137] [Examples 1-3, Comparative Example 1]

[0138] The following components were prepared for the purpose of preparing the composition. It should be noted that the viscosities of the components shown below are expressed using a cone-plate viscometer at 25°C and 55% RH at a shear rate of 10 s⁻¹. -1 The values ​​were obtained through measurement. Additionally, the softening points of each component are values ​​obtained based on measurements performed according to JIS K 7234:1986 (ring and ball method).

[0139] (A) Composition: A mixed difunctional bisphenol A and F type epoxy resin (a mixture of bisphenol A and bisphenol F type epoxy resins) that is liquid at 25°C. Trade name: EPICLON (registered trademark) EXA-835LV (manufactured by DIC Corporation). Epoxy equivalent: 165 g / eq. Viscosity (25°C): 2000 mPa·s (2 Pa·s).

[0140] It should be noted that the above epoxy resin (mixture) contains difunctional bisphenol A type epoxy resin (epoxy equivalent: about 180 g / eq) and difunctional bisphenol F type epoxy resin (epoxy equivalent: about 160 g / eq) which are liquid at 25°C and liquid at 25°C, in a mass ratio of about 50:50.

[0141] (B) Ingredients:

[0142] (B-1) Composition: Liquid difunctional bisphenol A type epoxy resin at 25℃. Trade name: jER (registered trademark) 834 (manufactured by Mitsubishi Chemical Corporation). Epoxy equivalent: 230-270 g / eq. Softening point: 30℃.

[0143] (B-2) Ingredients:

[0144] (B-2-1) A difunctional bisphenol A type epoxy resin that is solid at 25℃. Trade name: jER (registered trademark) 1001 (manufactured by Mitsubishi Chemical Corporation). Epoxy equivalent: 450-500 g / eq. Softening point: 64℃.

[0145] (B-2-2) Difunctional biphenyl epoxy resin, solid at 25℃, trade name jERYX (registered trademark) 4000H (manufactured by Mitsubishi Chemical Corporation), epoxy equivalent 187~197g / eq, softening point 105℃.

[0146] (C) Ingredients: Pentaerythritol tetra(3-mercaptobutyrate) Trade name: Karenz MT (registered trademark) PE1 (manufactured by Showa Denko Corporation) SH equivalent: 136 g / mol, SH base number in one molecule: 4

[0147] (D) Composition: Modified aliphatic polyamine adduct. Trade name: Fujicure (registered trademark) FXR-1081. Amine value: 115. Softening point: 125℃. Average particle size: 6.0 μm.

[0148] (E) Composition: p-tert-butylphenyl glycidyl ether, trade name: Adekaglycylol ED-509S; epoxy equivalent: 206 g / eq; viscosity (25℃): 20 mPa·s

[0149] (F) Composition: Spherical silica, trade name SC2500 (manufactured by ADMATECHS Co., Ltd.), average particle size 0.5μm.

[0150] Components (A) and (B) were weighed into a mixing container, and then component (C) was added. The mixture was stirred for 30 minutes using a mixer. Next, components (D), (E), and (F) were added, and the mixture was stirred for 10 minutes. The proportions (in parts by mass) of each component in the epoxy resin compositions of each example and comparative example are shown in Table 1. It should be noted that empty columns in Table 1 indicate that the corresponding component was not added. All tests (evaluations) shown below were conducted at 25°C.

[0151] <Experiment (Evaluation)>

[0152] [Viscosity]

[0153] Regarding the viscosity of the obtained epoxy resin composition, a cone-plate viscometer was used at 25°C and 55% RH with a shear rate of 10 s⁻¹. -1 The measurement shall be performed. It should be noted that the acceptable standard is below 2000 mPa·s, but if workability is taken into consideration, it is preferably below 1500 mPa·s, and more preferably 600 mPa·s.

[0154] Shear bond strength

[0155] For SUS304 (25×100×1.0mm, coefficient of linear expansion 18×10⁻⁶), ... -6 Each epoxy resin composition was coated onto a test piece ( / K), and the following plastic test pieces were then attached to it and secured with clips. At this point, the bonding area of ​​each plastic test piece was 25 × 10 mm. The mixture was cured in a hot air drying oven at 80°C for 60 minutes to obtain a cured product. After the cured product was allowed to return to room temperature, the shear bond strength (unit: MPa) was measured using a tensile testing machine according to JIS K 6850:1999 at a tensile speed of 50 mm / min.

[0156] (Material: Plastic)

[0157] 6-Nylon (25×100×1.5mm) has a linear expansion coefficient of 8×10⁻⁶. -5 / K

[0158] 6,6-Nylon (25×100×1.5mm) has a linear expansion coefficient of 10×10⁻⁶. -5 / K

[0159] PBT (polybutylene terephthalate) (25×100×1.5mm) has a coefficient of linear expansion of 2.5×10⁻⁶. -5 / KABS (acrylonitrile-butadiene-styrene copolymer) (25×100×1.5mm) has a linear expansion coefficient of 8×10. -5 / KGFRP (Glass Fiber Reinforced Plastic) (25×100×1.5mm) has a linear expansion coefficient of 5.8×10.-5 / K.

[0160] [Curing shrinkage rate]

[0161] Each epoxy resin composition was dripped into a transparent cylindrical plastic container to a depth of 6 mm and cured at 80°C for 60 minutes to obtain a cured product. The curing shrinkage rate was then determined using the following method.

[0162] (Method for calculating curing shrinkage rate)

[0163] The specific gravity (S) of the uncured epoxy resin composition was determined by the specific gravity cup method. g1 The determination was performed. Additionally, the mass of the solidified material in air (WA) and in water (distilled water) (WB) was measured using S... g2 The specific gravity (S) of the solidified material can be calculated using the formula WA / (WA-WB). g2 The specific gravity (S) of the uncured composition obtained by the above method. g1 ) and the specific gravity (S) of the cured product g2 ), through ΔV={(S g2 -S g1 ) / S g2 The curing shrinkage rate (ΔV) is calculated using the formula}×100 and used as the curing shrinkage rate.

[0164] (Qualification standard) Curing shrinkage rate below 5.0%.

[0165] [Table 1]

[0166]

[0167] *The functional group equivalent ratios in the table are calculated based on the minimum functional group equivalent of each component.

[0168] As demonstrated in the tests above, the epoxy resin compositions of the embodiments can be cured by heating at 80°C for 60 minutes, thereby exhibiting good adhesive strength (high shear bond strength). Thus, curing at temperatures below 100°C is possible, confirming that the epoxy resin compositions of the embodiments possess excellent low-temperature curing properties.

[0169] In the evaluation of shear bond strength, as shown in Table 1, compared with Comparative Example 1 which did not contain component (B), the epoxy resin compositions of Examples 1-3 exhibited good shear bond strength in the combination of all test pieces. Furthermore, the epoxy resin compositions of Examples 1-3 also showed low curing shrinkage. Moreover, the epoxy resin compositions of Examples 1-3 had low viscosity, with the viscosity of the compositions of Examples 1 and 3 being particularly low.

[0170] In summary, the epoxy resin composition of this invention exhibits good adhesion to dissimilar materials by containing components (A) to (E). Furthermore, the epoxy resin composition of this invention demonstrates good low-temperature curing properties, low viscosity, and excellent curing shrinkage.

[0171] Industrial availability

[0172] The epoxy resin composition of this invention exhibits excellent adhesion to dissimilar materials. Furthermore, the epoxy resin composition of this invention possesses low-temperature curing properties for good workability and low viscosity, resulting in low curing shrinkage, making it highly useful as an adhesive, coating agent, and potting compound for various components.

[0173] This application is based on Japanese Patent Application No. 2020-161114, filed on September 25, 2020, the entire contents of which are incorporated herein by reference.

Claims

1. An epoxy resin composition, characterized in that, It contains the following components (A) to (E): (A) A compound that is liquid at 25°C, has more than two epoxy groups per molecule, and has an epoxy equivalent of less than 210 g / eq. (B) The following components (B-1) or a combination of the following components (B-1) and (B-2), (B-1) A compound that is liquid at 25°C, has two or more epoxy groups per molecule, and has an epoxy equivalent of 210 g / eq or more. (B-2) Compounds that are solid at 25°C and have two or more epoxy groups per molecule. (C) Thiol curing agent, (D) Latent curing agent, (E) Reactive diluent, The content of component (B) is 10 to 80 parts by mass relative to 100 parts by mass of component (A). Component (C) is a secondary thiol compound having a secondary thiol group. The content of component (C) is 50 to 300 parts by mass relative to 100 parts by mass of component (A).

2. The epoxy resin composition according to claim 1, characterized in that, The component (A) is a bisphenol type epoxy resin.

3. The epoxy resin composition according to claim 1 or 2, characterized in that, The softening point of component (B-1) is above 25°C and below 35°C.

4. The epoxy resin composition according to claim 1 or 2, characterized in that, The component (B) is a bisphenol type epoxy resin and / or a biphenyl type epoxy resin.

5. The epoxy resin composition according to claim 1 or 2, characterized in that, The (C) component is a compound having three or more SH groups.

6. The epoxy resin composition according to claim 1 or 2, characterized in that, It also contains (F) inorganic filler.

7. The epoxy resin composition according to claim 1 or 2, characterized in that, The curing shrinkage rate is less than 5%.

8. The epoxy resin composition according to claim 1 or 2, characterized in that, Used for bonding and / or sealing between materials with different coefficients of linear expansion.

9. A cured product of the epoxy resin composition according to any one of claims 1 to 8.

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