Epoxy resin composition and cured product

Abstract

An epoxy resin composition is provided which has excellent adhesiveness to dissimilar materials.　This epoxy resin composition contains (A) to (E) below:　(A) a compound which 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; (B) (B-1) a compound which is liquid at 25°C, has two or more epoxy groups in one molecule and has an epoxy equivalent of greater than or equal to 210 g / eq, and / or (B-2) a compound which 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] The present invention relates to an epoxy resin composition having excellent adhesion to dissimilar materials and its cured product. [Background technology]

[0002] In recent years, with the increasing diversification of materials, adhesives are required to be able to bond dissimilar materials with different coefficients of thermal expansion. Among these, epoxy resins are used in a wide range of fields because they exhibit good adhesive strength and have excellent chemical resistance and durability, and are also suitably used for bonding dissimilar materials. As an example of such epoxy resins, for example, Japanese Patent Publication No. 2019-156965 proposes an epoxy resin composition that includes (A) a thiol-based curing agent, (B) a polyfunctional epoxy resin, and (C) a crosslinking density modifier containing a monofunctional epoxy resin, wherein the number (amount) of thiol groups and the number (amount) of epoxy groups in these components have a specific relationship. [Overview of the project] [Problems that the invention aims to solve]

[0003] However, conventional adhesives (epoxy resins) used for bonding dissimilar materials do not exhibit sufficient adhesion to those materials, and further improvements in this adhesion are needed. Furthermore, conventional adhesives (epoxy resins) have drawbacks such as high curing temperatures and high viscosity, resulting in poor workability. Moreover, when the viscosity of conventional adhesives (epoxy resins) is reduced to improve workability, curing shrinkage is significant, sometimes causing distortion in the bonded components during curing.

[0004] The present invention has been made in view of the above circumstances, and aims to provide an epoxy resin composition having 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, has low curability and low viscosity for good workability, and further exhibits low curing shrinkage. Yet another object of the present invention is to provide a cured product obtained by curing the above epoxy resin composition. [Means for solving the problem]

[0005] As a result of diligent research to solve the above problems, the inventors of the present invention have found that the epoxy resin composition described in detail below has excellent adhesion to dissimilar materials, and have completed the present invention.

[0006] The gist of this invention is described below.

[0007] [1] An epoxy resin composition comprising the following components (A) to (E): (A) Compounds that are liquid at 25°C, have two or more epoxy groups in one molecule, and have an epoxy equivalent 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 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) Thiol curing agent (D) Latent curing agent (E) Reactive diluent.

[0008] [2] The epoxy resin composition according to [1], wherein the component (A) is a bisphenol-type epoxy resin.

[0009] [3] The epoxy resin composition according to [1] or [2], wherein the content of component (B) is 1 to 100 parts by mass per 100 parts by mass of component (A).

[0010] [4] The epoxy resin composition according to any one of [1] to [3], wherein the component (B) is a bisphenol type epoxy resin and / or a biphenyl type epoxy resin.

[0011] [5] The epoxy resin composition according to any one of [1] to [4], wherein the component (C) is a compound having 3 or more SH groups.

[0012] [6] The epoxy resin composition according to any one of [1] to [5], wherein the content of the component (C) is 50 to 300 parts by mass with respect to 100 parts by mass of the component (A).

[0013] [7] The epoxy resin composition according to any one of [1] to [6], further comprising (F) an inorganic filler.

[0014] [8] The epoxy resin composition according to any one of [1] to [7], having a curing shrinkage rate of 5% or less.

[0015] [9] The epoxy resin composition according to any one of [1] to [8], which is used for adhesion and / or sealing between adherends having different linear expansion coefficients.

[0016]

[10] A cured product of the epoxy resin composition according to any one of [1] to [9].

Mode for Carrying Out the Invention

[0017] Embodiments of the present invention will be described below. Note that the present disclosure is not limited only to the following embodiments. In this specification, "X to Y" means a range including the numerical values (X and Y) described before and after as the lower limit value and the upper limit value, and means "X or more and Y or less". Also, concentration and % represent mass concentration and mass % respectively unless otherwise specified, and the ratio is a mass ratio unless otherwise specified. Also, unless otherwise specified, measurements of operations and physical properties are performed under the conditions of room temperature (20 to 25 ° C) / relative humidity 40 to 55% RH. Also, "A and / or B" means including each of A and B and combinations thereof.

[0018] [Epoxy resin composition] The epoxy resin composition according to one aspect of the present invention (hereinafter, also referred to as "epoxy resin composition" or simply "resin composition") contains the following components (A) to (E): (A) 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 (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 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) Thiol curing agent (D) Latent curing agent (E) Reactive diluent

[0019] The epoxy resin composition according to one aspect of the present invention has excellent adhesion to dissimilar materials. In addition, the epoxy resin composition according to one aspect of the present invention has low-temperature curability and low viscosity for exhibiting good workability in addition to excellent adhesion to dissimilar materials, and further has low curing shrinkage, so it is very useful

[0020] Although the details of this mechanism are unknown, the epoxy resin composition according to the present invention contains component (B) having a higher molecular weight (higher epoxy equivalent) compared to component (A) together with component (A), so it is considered that an excellent effect of improving adhesion to dissimilar materials can be obtained. On the other hand, when the epoxy resin composition does not contain the compound corresponding to component (B), the adhesion to dissimilar materials decreases (Comparative Example​​​​​​​​​​​​ In this specification, "liquid at 25°C" means a state in which the substance is fluid at 25°C. Specifically, "liquid at 25°C" means a substance that satisfies at least one of the following conditions: (i) and (ii); (i) The viscosity measured using a cone-plate rotational viscometer at 25°C is 100 Pa·s or less; (ii) The softening point or melting point (or the softening point if it has both a softening point and a melting point) is less than 35°C.

[0024] The softening point is determined by a method compliant with JIS K 7234:1986 (ring-sphere method). The melting point is determined by differential scanning calorimetry (DSC).

[0025] Furthermore, in this specification, the epoxy equivalent is a value measured in accordance with JIS K 7236:2001. If the epoxy equivalent cannot be determined by this method, it may be calculated by dividing the molecular weight of the epoxy resin in question by the number of epoxy groups contained in one molecule of the epoxy resin.

[0026] (A) The epoxy equivalent of component (A) is preferably 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 180 g / eq or less, from the viewpoint of exhibiting low-temperature curability and low curing shrinkage.

[0027] Furthermore, from the viewpoint of lowering the viscosity of the resulting 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.

[0028] Furthermore, the softening point or melting point of component (A) (or the softening point if it has both a softening point and a melting point) is preferably 10°C or higher and less than 35°C, and more preferably 15°C or higher and 30°C or lower.

[0029] (A) The compound of component (A) is not particularly limited in the number of epoxy groups contained in one molecule as long as there are two or more, but it is preferably 2 to 6 (2 to 6 functional epoxy resins), more preferably 2 to 3 (2 to 3 functional epoxy resins), and particularly preferably 2 (2 functional epoxy resins).

[0030] Specific examples of compounds of component (A) include, but are not limited to, 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; phenol novolac type epoxy resin; glycidylamine type epoxy resin; dimer acid modified epoxy resin; and alicyclic epoxy resin. These may be used individually or mixed together. In particular, 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 is particularly preferably composed of both bisphenol A type epoxy resin and bisphenol F type epoxy resin.

[0031] (A) The compound (epoxy resin) used as component may be either a synthetic or commercially available product.

[0032] (A) Examples of commercially available products of component (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), EPICLON(registered trademark) 840, 840S, 850, 850S, 850CRP, 850-LC, 830, 835, EXA-830LVP, EXA-830LVP, E Examples include, but are not limited to, XA-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).

[0033] The compound (epoxy resin) as component (A) above may be used alone or in combination of two or more types. When two or more types are used in combination, the content of component (A) refers to the total amount.

[0034] [(B) Component] The epoxy resin according to the present invention contains component (B) below, which includes component (B-1) and / or component (B-2): (B-1) Components: Compounds that are liquid at 25°C, have two or more epoxy groups in one molecule, and have an epoxy equivalent of 210 g / eq or more. (B-2) Components: A compound that is solid at 25°C and has two or more epoxy groups in one molecule.

[0035] Component (B), when combined with component (A) above, can improve adhesion to dissimilar materials while maintaining low curing shrinkage.

[0036] Furthermore, the fact that the compound is "liquid at 25°C" follows the definition described in the explanation of component (A) above. Similarly, the epoxy equivalent of the compound is a value measured by the measurement method described in the explanation of component (A) above.

[0037] In this specification, "solid at 25°C" means a state in which there is no fluidity at 25°C. Specifically, "solid at 25°C" means a state that satisfies at least one of the following conditions (i') and (ii'): (i') The viscosity measured using a cone-plate rotational viscometer at 25°C exceeds 100 Pa·s; (ii') The softening point or melting point (or the softening point if it has both a softening point and a melting point) is 35°C or higher. The method for measuring the softening point and melting point shall be as described in the description of component (A) above.

[0038] The epoxy equivalent of component (B-1) is preferably 210 to 1000 g / eq, more preferably 230 to 700 g / eq, even more preferably 230 to 500 g / eq, and most preferably 230 to 300 g / eq. If the epoxy equivalent of component (B-1) is 210 g / eq or more, and more preferably 230 g / eq or more, it is possible to improve the adhesion to dissimilar materials while maintaining low curing shrinkage. Furthermore, if the epoxy equivalent of component (B-1) is 1000 g / eq or less, an epoxy resin composition with low viscosity and excellent workability can be obtained.

[0039] Furthermore, from the viewpoint of lowering the viscosity of the resulting 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 most preferably 0.5 to 5 Pa·s.

[0040] Furthermore, the softening point or melting point of component (B-1) (or the softening point if it has both a softening point and a melting point) is preferably 10°C or higher and less than 35°C, and more preferably greater than 25°C and less than 35°C.

[0041] The epoxy equivalent of component (B-2) is not particularly limited, but 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. If the epoxy equivalent of component (B-2) is 100 g / eq or more, and more preferably 230 g / eq or more, it is possible to improve the adhesion to dissimilar materials while maintaining low curing shrinkage. Furthermore, if the epoxy equivalent of component (B-2) is 3000 g / eq or less, and more preferably 800 g / eq or less, an epoxy resin composition with low viscosity and excellent workability can be obtained.

[0042] The softening point or melting point of component (B-2) (or the softening point if it has both a softening point and a melting point) is preferably 40 to 200°C, more preferably 50 to 150°C, even more preferably 55 to 130°C, and most preferably 60 to 100°C. If the softening point or melting point of component (B-2) is 40 to 200°C, it is possible to obtain an epoxy resin composition with good compatibility with component (A) and low viscosity.

[0043] For the compounds of component (B) (components (B-1) and (B-2)), the number of epoxy groups contained in one molecule is not particularly limited as long as there are two or more, but it is preferably 2 to 6 (2-6 functional epoxy resin), more preferably 2 to 3 (2-3 functional epoxy resin), and particularly preferably 2 (2 functional epoxy resin). By setting the number of epoxy groups within the above range, it is possible to improve the adhesion to dissimilar materials while maintaining low curing shrinkage.

[0044] Specific examples of component (B) (components (B-1) and (B-2)) include, but are not limited to, bisphenol-type epoxy resins, naphthalene-type epoxy resins, dicyclopentadiene-type epoxy resins, phenol novolac resins, cresol novolac resins, and biphenyl-type epoxy resins. These may be used individually or mixed in combination of two or more types. In particular, 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 as above, component (B) is preferably at least one selected from the group consisting of bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and biphenyl-type epoxy resin.

[0045] Furthermore, from the viewpoint of obtaining an epoxy resin composition with excellent low viscosity and low-temperature curing properties, it is preferable that component (B) contains (B-1). Similarly, from the same viewpoint, it is preferable that component (B) contains only component (B-1) (i.e., component (B) is component (B-1)).

[0046] (B) The compound (epoxy resin) as component may be either a synthetic or commercially available product.

[0047] (B) Examples of commercially available products of component (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, HP-4770 (manufactured by DIC Corporation).

[0048] The compound (epoxy resin) as component (B) above may be used alone or in combination of two or more types. When two or more types are used in combination, the content of component (B) refers to the total amount.

[0049] The content of component (B) is preferably 1 to 100 parts by mass, 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, per 100 parts by mass of component (A). If the content of component (B) is 1 part by mass or more, and more preferably 5 parts by mass or more, adhesion to dissimilar materials can be improved while maintaining low curing shrinkage. Furthermore, if 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.

[0050] [(C) component] Component (C) in the epoxy resin according to the present invention is a thiol curing agent. The thiol curing agent as component (C) is not particularly limited as long as it has one or more thiol groups (SH groups) in one molecule. 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 to 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.

[0051] From the viewpoint of low-temperature curing properties, the thiol equivalent of component (C) is not particularly limited, but is preferably 50 to 500 g / eq (g / mol), more preferably 70 to 300 g / eq (g / mol), even more preferably 90 to 200 g / eq (g / mol), and most preferably 110 to 150 g / eq (g / mol). The thiol equivalent can be determined by iodine titration. If the thiol equivalent cannot be determined by this method, it may be calculated by dividing the molecular weight of the thiol curing agent by the number of SH groups contained in one molecule of the thiol curing agent.

[0052] The substitution position of the SH group in the thiol curing agent as component (C) is not particularly limited and may be located at the end of the compound or as a side chain. In other words, the SH group in the thiol curing agent as component (C) may be a primary thiol group, a secondary thiol group, or a tertiary thiol group. In particular, from the viewpoint of reducing curing shrinkage of the epoxy resin composition, it is preferable that the SH group be a primary thiol group or a secondary thiol group, and more preferably a secondary thiol group. That is, from the viewpoint of reducing curing shrinkage of the epoxy resin composition, the thiol curing agent as component (C) is preferably a primary thiol compound or a secondary thiol compound, and more preferably a secondary thiol compound. Note that a primary thiol group means that the carbon bonded to the sulfur atom (the carbon to which the SH group is bonded) is a primary carbon atom, and similarly, a secondary thiol group and a tertiary thiol group mean that the carbon bonded to the sulfur atom (the carbon to which the SH group is bonded) is a secondary carbon atom and a tertiary carbon atom, respectively.

[0053] (C)Specific examples of components include primary thiol compounds such as trimethylolpropane tris(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), and dipentaerythritol hexakis(3-mercaptopropionate); pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3- Examples include, but are not limited to, secondary thiol compounds such as mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropanetris(3-mercaptobutyrate), trimethylolethanetris(3-mercaptobutyrate), trimethylolpropanetris(3-mercaptobutyrate), and trimethylolethanetris(3-mercaptobutyrate). These may be used individually or in combination of two or more.

[0054] (C) The thiol curing agent as component may be either a synthetic or commercially available product.

[0055] (C) Commercially available products of component (C) include, but are not limited to, TMMP, TEMPIC, PEMP, EGMP-4, and DPMP manufactured by SC Organic Chemicals Co., Ltd., and Karens MT(registered trademark) PE1, BD1, NR1, and TPMB manufactured by Showa Denko K.K.

[0056] The thiol curing agent as component (C) above may be used alone or in combination of two or more types. When two or more types are used in combination, the content of component (C) refers to the total amount.

[0057] The content of component (C) is preferably 50 to 300 parts by mass, more preferably 130 to 250 parts by mass, and most preferably 150 to 230 parts by mass, per 100 parts by mass of component (A). If the content of component (C) is 50 parts by mass or more, an epoxy resin composition with excellent low-temperature curability and adhesion can be obtained. Furthermore, if the content of component (C) is 300 parts by mass or less, good adhesive strength can be maintained.

[0058] Furthermore, the content of component (C) is preferably 50 to 300 parts by mass, 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, based on 100 parts by mass of the total of components (A) and (B). If the content of component (C) is 50 parts by mass or more, an epoxy resin composition with excellent low-temperature curability and adhesion can be obtained. Also, if the content of component (C) is 300 parts by mass or less, good adhesive strength can be maintained.

[0059] The functional group equivalent ratio of components (A) and (B) to component (C) ({functional group equivalent of component (A) + functional group equivalent of component (B)} / functional group equivalent of (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. When the above functional group equivalent ratio is 0.1 to 2.0, the curability of the epoxy resin composition can be improved. The above functional group equivalent ratio is obtained by calculating the ratio of the values ​​obtained by dividing the content (amount blended) of each component by the epoxy equivalent or SH equivalent ({(A) + (B)} / (C)).

[0060] The method for determining the above functional group equivalent ratio will be explained in detail below: First, for components (A) and (B), calculate the epoxy functional group equivalent, that is, the total number of epoxy groups contained in each component. Specifically, divide the mass (g) of epoxy resin contained in components (A) and (B) by the epoxy equivalent of that epoxy resin. Similarly, for component (C), calculate the thiol functional group equivalent, that is, the total number of SH groups contained in component (C). Specifically, divide the mass (g) of the thiol compound contained in component (C) by the thiol (SH) equivalent of that thiol compound. If a single component contains multiple epoxy resins or thiol compounds, calculate the above value (functional group equivalent) for each epoxy resin or thiol compound, and take the weighted average of these values ​​as the epoxy functional group equivalent or thiol functional group equivalent for each component.

[0061] Next, the functional group equivalent ratio of components (A) and (B) to component (C) can be determined 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).

[0062] [(D) component] Component (D) contained in the epoxy resin according to the present invention is a latent curing agent. Here, a latent curing agent is a curing agent that, when dispersed in components (A) and (B) above, ensures storage stability such as minimal changes in viscosity and physical properties over time.

[0063] Component (D) is not particularly limited as long as it is a latent curing agent as described above, but it is preferable that it promotes curing by component (C) and is a thermosetting compound.

[0064] Furthermore, as component (D), it is preferable to use compounds having an imidazole skeleton; epoxy adduct compounds obtained by adding tertiary amine compounds, etc., to an epoxy resin and stopping the reaction midway (reaction products of epoxy compounds and tertiary amine compounds, etc.); and it is even more preferable to use fine powders obtained by pulverizing these compounds. In particular, from the viewpoint of maintaining low-temperature curability and low curing shrinkage, component (D) is preferably a modified aliphatic polyamine adduct or a modified alicyclic polyamine adduct, and is especially preferred to be a modified aliphatic polyamine adduct.

[0065] (D) When component (D) is a compound having an imidazole skeleton or an epoxy adduct compound, its amine value is preferably 50 to 300, more preferably 70 to 200, and most preferably 80 to 150. If the above amine value is 50 to 300, the storage stability and low-temperature curability of the resulting epoxy resin composition can be well maintained. The amine value is the mass (mg) of potassium hydroxide (KOH) equivalent to the hydrochloric acid required to neutralize the primary, secondary, and tertiary amines contained in 1 g of the epoxy adduct compound. The amine value can be measured according to ASTM D2074.

[0066] From the viewpoint of improving curability (increasing curing speed) and ensuring good storage stability, component (D) is preferably solid at 25°C. Similarly, from the viewpoint of low-temperature curability and storage stability, the softening point of component (D) is preferably 70 to 300°C, more preferably 90 to 200°C, and most preferably 100 to 130°C.

[0067] The average particle size of component (D) is preferably 0.1 to 50 μm, more preferably 1 to 30 μm, even more preferably 2 to 20 μm, and most preferably 5 to 10 μm. When the average particle size is 0.1 to 50 μm, the dispersibility when mixed with components (A) and (B) is good, and an epoxy resin composition exhibiting stable low-temperature curing properties can be obtained. Methods for measuring the average particle size include particle size and shape distribution analyzers using laser diffraction scattering or microsorting control, as well as image analysis using optical microscopes, electron microscopes, etc.

[0068] (D) The latent curing agent as component may be either a synthetic or commercially available product.

[0069] Examples of commercially available products containing component (D) include, but are not limited to, Amicure® 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® FXE-1000, FXR-1030, FXR-1081 (manufactured by T&K TOKA Co., Ltd.), and Curazol® SIZ, 2MZ-H, C11Z, C17Z, 2PZ, 2PZ-PW, 2P4MZ (manufactured by Shikoku Chemicals Co., Ltd.).

[0070] The latent curing agent as component (D) above may be used alone or in combination of two or more types. When two or more types are used in combination, the content of component (D) refers to the total amount.

[0071] The content of component (D) is preferably 0.001 to 30 parts by mass, 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, per 100 parts by mass of component (C). When the content of component (D) is 0.001 to 30 parts by mass, the low-temperature curability can be maintained while good storage stability of the epoxy resin composition.

[0072] [(E) component] Component (E) contained in the epoxy resin according to the present invention is a reactive diluent. Here, a reactive diluent is a compound that functions as a solvent and has a group that reacts with components (A) to (D) itself.

[0073] Component (E) is not particularly limited as long as it is a reactive diluent as described above, but from the viewpoint of reducing the viscosity of the epoxy resin composition, it is preferable that it be a compound having one epoxy group in one molecule.

[0074] From the viewpoint of lowering the viscosity of the resulting 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.

[0075] The epoxy equivalent of component (E) is preferably 100 to 500 g / eq, more preferably 150 to 300 g / eq, and most preferably 170 to 250 g / eq. When the epoxy equivalent is 100 to 500 g / eq, an epoxy resin composition with low viscosity and excellent curing shrinkage can be obtained while maintaining good curability of the epoxy resin composition.

[0076] Specific examples of component (E) include, but are not limited to, phenyl glycidyl ether, cresyl 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, cyclohexanedimethyl diglycidyl ether, neodecanoate glycidyl ester, or glycidyl ethers with polyethylene glycol or polypropylene glycol as the main skeleton. These may be used individually or in combination of two or more. When two or more are used in combination, the content of component (E) refers to the total amount.

[0077] Among the above, from the viewpoint of improving adhesion to dissimilar materials while maintaining low curing shrinkage, component (E) preferably contains p-tert-butylphenylglycidyl ether.

[0078] Furthermore, the content of component (E) is preferably 10 to 300 parts by mass, 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, based on 100 parts by mass of the total of (A) and (B). When the content of component (E) is 10 to 300 parts by mass, an epoxy resin composition having low viscosity can be obtained while maintaining good adhesive strength.

[0079] [(F) component] The epoxy resin composition according to the present invention may further contain an inorganic filler as component (F) in addition to the above components (A) to (E).

[0080] (F) Component can be any known material used as an inorganic filler. Specific examples of (F) component include, but are not limited to, alumina powder, calcium carbonate powder, talc powder, silica powder, fumed silica powder, silver powder, nickel powder, palladium powder, carbon powder, tungsten powder, and plating powder. These may be used individually or in combination of two or more. When two or more are used in combination, the content of (E) component refers to the total amount.

[0081] Among the above, from the viewpoint of improving adhesive strength, component (F) preferably contains silica powder or fumed silica powder, more preferably contains silica powder, and particularly preferably contains spherical silica powder.

[0082] The average particle size of component (F) is preferably 0.01 to 50 μm, more preferably 0.1 to 30 μm, and particularly preferably 0.1 to 5 μm. If the average particle size is 0.01 to 50 μm, the viscosity of the resulting epoxy resin composition can be effectively suppressed.

[0083] The content of component (F) is preferably 1 to 300 parts by mass, more preferably 30 to 200 parts by mass, and most preferably 50 to 150 parts by mass, based on 100 parts by mass of the total of components (A) and (B). When the content of component (F) is 1 to 300 parts by mass, it is possible to improve the adhesive strength while suppressing an increase in the viscosity of the resulting epoxy resin composition.

[0084] [Optional ingredients] The epoxy resin according to the present invention may further contain, in addition to the above components (A) to (E), additives such as organic fillers (excluding components (A) to (E)), pigments, dyes, silane coupling agents, leveling agents, rheology control agents, and preservative stabilizers as optional components, to the extent that the properties of the present invention are not impaired.

[0085] As the organic filler, powders of organic materials (excluding components (A) to (E)) composed of rubber, elastomers, plastics, polymers (or copolymers), etc., can be used. In addition, organic fillers having a multilayer structure such as a core-shell type can also be used as the organic filler. These may be used individually or in combination of two or more types.

[0086] 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, preferred organic fillers are fillers made of polymers or copolymers thereof of acrylic acid esters and / or methacrylic acid esters, or fillers made of polymers or copolymers thereof of styrene compounds. The preferred content of the organic filler (total amount if two or more types are included) is preferably 1 to 50 parts by mass, and more preferably 5 to 30 parts by mass, per 100 parts by mass of component (A).

[0087] Examples of the silane coupling agents include glycidyl group-containing silane coupling agents such as 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldipropyloxysilane, 3-glycidoxypropyldimethylmonomethoxysilane, 3-glycidoxypropyldimethylmonoethoxysilane, 3-glycidoxypropyldimethylmonopropyloxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane; vinyl group-containing silane coupling agents such as vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, and vinyltrimethoxysilane; 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyldimethylmonomethoxysilane, and 3-methacryloxypropylmethylmonomethoxysilane. Examples include (meth)acrylic group-containing silane coupling agents such as criloxypropyldimethylmonoethoxysilane, 3-acryloxypropylmethyldipropyloxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldiethoxysilane, 3-acryloxypropylmethyldipropyloxysilane, 3-acryloxypropyldimethylmonopropyloxysilane, 3-acryloxypropyldimethylmonomethoxysilane, 3-acryloxypropyldimethylmonoethoxysilane, 3-acryloxypropyldimethylmonopropyloxysilane, and 3-methacryloxypropyltrimethoxysilane; amino group-containing silane coupling agents such as N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; γ-mercaptopropyltrimethoxysilane; and γ-chloropropyltrimethoxysilane. Among these, glycidyl group-containing silane coupling agents are preferred from the viewpoint of superior adhesive strength. These may be used individually or in combination of two or more.The preferred range for the content of the silane coupling agent (total amount if two or more types are included) is preferably 0.1 to 20 parts by mass per 100 parts by mass of component (A).

[0088] As the preservative stabilizer, borate esters, phosphoric acid, alkyl phosphate esters, and p-toluenesulfonic acid can be used. Examples of borate esters include tributyl borate, trimethoxyboroxine, 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 individually or in combination. Considering the effect on curing shrinkage, the preservative stabilizer is preferably one or more selected from the group consisting of phosphoric acid, alkyl phosphate esters, borate esters, trimethoxyboroxine, and p-toluenesulfonic acid methyl, and more preferably phosphoric acid or borate esters. From the viewpoint of maintaining low-temperature curability and reducing curing shrinkage, the preferred content of the preservative stabilizer (total amount if two or more are included) is preferably 0.1 to 10 parts by mass per 100 parts by mass of component (A).

[0089] <Method for producing epoxy resin composition> The method for producing the epoxy resin composition according to the present invention is not particularly limited and can be produced by conventionally known methods. For example, the epoxy resin composition according to the present invention can be obtained by weighing predetermined amounts of components (A) to (E), component (F) which is added as needed, and optional components which are added sequentially or simultaneously in any order, and then mixing them using a mixing means such as a mixer. At this time, the production 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.

[0090] <Application Method> The epoxy resin composition according to the present invention can be applied to an adherend using methods similar to those used for applying known sealants and adhesives. For example, methods such as dispensing using an automatic applicator, spraying, inkjet printing, screen printing, gravure printing, dipping, and spin coating can be used.

[0091] From the viewpoint of coatability, the viscosity (at 25°C) of the epoxy resin composition according to the present 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, the lower limit is not particularly limited, but is for example 100 mPa·s or more, and more preferably 200 mPa·s or more.

[0092] <Curing method and cured product> The epoxy resin composition according to the present invention can be cured by heating. Therefore, another aspect of the present invention is a cured product (cured epoxy resin composition) obtained by curing the above epoxy resin composition.

[0093] Another characteristic of the epoxy resin composition according to the present invention is its low curing shrinkage when cured into a cured product. Specifically, a curing shrinkage rate of 5% or less is preferable. The above curing shrinkage rate is the value obtained by the method described in the examples. When the epoxy resin composition according to the present invention is used in applications such as adhesives, a curing shrinkage rate of 4.5% or less is more preferable in order to suppress distortion of the adherend. On the other hand, there is no particular lower limit to the above curing shrinkage rate, but it is substantially around 0%.

[0094] The method for producing the cured product is not particularly limited, and known methods can be used. One example is a method in which the epoxy resin composition according to the present invention is applied to a substrate and then heated to cure it. In this case, the thickness of the applied film is not particularly limited and is adjusted as appropriate within a range that allows adhesion to the substrate. Furthermore, the heating temperature and heating time (curing time) conditions are not particularly limited as long as they allow the epoxy resin composition to cure sufficiently, but as a specific example of preferred heating conditions, for example, the heating temperature is preferably 50°C to 200°C, more preferably 50°C or more and less than 200°C, even more preferably 60°C to 150°C, and particularly preferably 70°C to 100°C. Thus, one of the features of the epoxy resin composition according to the present invention is its low curing temperature. Furthermore, the curing time is not particularly limited, but for example, it is preferably 30 seconds to 5 hours, and more preferably 1 minute to 3 hours. As a more specific example of heating temperature and heating time (curing time), at a temperature of 50°C or more and less than 200°C, it is preferably 1 minute to 3 hours, and more preferably 2 minutes to 2 hours.

[0095] <Adherend> The epoxy resin composition according to the present invention exhibits excellent adhesion to dissimilar materials, making it suitable for bonding and / or sealing between components with different coefficients of thermal expansion, such as plastics and metals.

[0096] In this specification, "different materials" refers to two or more materials that have different properties, specifically materials with different coefficients of thermal expansion. That is, the epoxy resin composition according to the present invention is preferably used for bonding and / or sealing between adherends with different coefficients of thermal expansion.

[0097] The difference in the coefficients of linear thermal expansion between materials with different coefficients of linear thermal expansion is not particularly limited, but for example, 0.1 × 10 -6 / K~300×10 -6 It is preferable that it be / K, which is 1 × 10 -6 / K~200×10 -6 It is more preferable that it be / K, 5 × 10 -6 / K~100×10 -6 It is especially preferable if it is / K.

[0098] 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 value. Furthermore, the linear expansion coefficient is determined according to the measurement method for each material, which conforms to JIS Z 2285:2003 for metallic materials and JIS K 7197:2012 for plastics.

[0099] Specific examples of bonding between dissimilar materials include, for example, metals to metals, metals to plastics, metals to rubbers, plastics to rubbers, plastics to plastics, and rubbers to rubbers. Among these, metals to metals, metals to plastics, and plastics to plastics are preferred, with metals to plastics being more preferred.

[0100] Examples of metals to be bonded include iron, stainless steel, copper, nickel, zinc, aluminum, magnesium, gold, silver, and titanium. Examples of plastics to be bonded include fiber-reinforced plastics (FRP), glass fiber reinforced plastics (GFRP), carbon fiber reinforced plastics (CFRP), polyacrylic, polyester, polyamide, acrylonitrile-butadiene-styrene copolymer (ABS), nylon 6, nylon 6,6, polycarbonate, polyacetal, polyethylene terephthalate, polybutylene terephthalate (PBT), polyphenylene sulfide, polyphenylene ether, polyether ether ketone, polyethylene, and polypropylene. Examples of rubbers to be bonded include nitrile rubber, urethane rubber, silicone rubber, and EPDM. More detailed specific examples of bonding and / or sealing between dissimilar materials include bonding at least two or more adherends selected from these materials to each other.

[0101] Furthermore, each of the materials (each of the substrates to be bonded) listed above may or may not be surface-treated.

[0102] <Application> The epoxy resin composition according to the present invention can be used in a variety of applications. Specific examples of applications include: in the automotive field, bonding, sealing, casting, and coating of automotive switch parts, headlamps, engine internal components, electrical components, drive engines, brake fluid tanks, body panels such as front hoods, fenders, and doors, windows, etc.; in the electronic materials field, 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, hard disks, etc.; and in the battery field, lithium batteries, lithium-ion batteries, manganese batteries, etc. In the field of optical components, it can be used for bonding, sealing, and coating of optical fiber materials around optical switches and optical connectors, optical passive components, optical circuit components, and optoelectronic integrated circuits. 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, projection lenses for projection televisions, etc. In the field of infrastructure, it can be used for bonding, lining, sealing, and coating of gas pipes, water pipes, etc. Among these, the epoxy resin composition according to the present invention has low viscosity, so it can be applied in minute amounts and is suitable for use on minute parts. [Examples]

[0103] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, the tests were conducted under conditions of 25°C and 55% RH.

[0104] <Preparation of epoxy resin composition> [Examples 1-3, Comparative Example 1] The following components were prepared to create the composition. The viscosity of each component listed below was measured using a cone-plate viscometer at 25°C and 55%RH under a shear rate of 10s.-1 The values ​​measured are shown. In addition, the softening points of each component are shown as values ​​measured in accordance with JIS K 7234:1986 (ring-sphere method).

[0105] (A) Ingredients: A liquid, bifunctional bisphenol A and F mixed epoxy resin at 25°C (a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin). Product name: EPICLON (registered trademark) EXA-835LV (manufactured by DIC Corporation). Epoxy equivalent: 165 g / eq. Viscosity (25°C): 2000 mPa·s (2 Pa·s). The epoxy resin (mixture) described above contains a liquid bifunctional bisphenol A type epoxy resin (epoxy equivalent: approximately 180 g / eq) and a liquid bifunctional bisphenol F type epoxy resin (epoxy equivalent: approximately 160 g / eq) at 25°C, in a mass ratio of approximately 50:50.

[0106] (B) Ingredients: (B-1) Ingredients: Difunctional bisphenol A type epoxy resin that is liquid at 25°C. Product name: jER(registered trademark)834 (manufactured by Mitsubishi Chemical Corporation). Epoxy equivalent: 230-270 g / eq. Softening point: 30°C. (B-2) Ingredients: (B-2-1) A bifunctional bisphenol A epoxy resin that is solid at 25°C. Product name: jER(registered trademark)1001 (manufactured by Mitsubishi Chemical Corporation). Epoxy equivalent: 450-500 g / eq. Softening point: 64°C. (B-2-2) A bifunctional biphenyl epoxy resin that is solid at 25°C. Product name: jERYX (registered trademark) 4000H (manufactured by Mitsubishi Chemical Corporation). Epoxy equivalent: 187-197 g / eq. Softening point: 105°C. (C) Ingredients: Pentaerythritol tetrakis(3-mercaptobutyrate) Product name: Karenz MT (registered trademark) PE1 (manufactured by Showa Denko Corporation) SH equivalent: 136 g / mol Number of SH groups per molecule: 4 (D) Ingredients: Modified aliphatic polyamine adduct Product name: Fujicure (registered trademark) FXR-1081 Amine value 115 Softening point 125℃ Average particle size: 6.0μm (E) Component: p-tert-butylphenyl glycidyl ether, trade name Adeka Glycilol ED-509S, epoxy equivalent: 206 g / eq, viscosity (25°C): 20 mPa·s (F) Component: spherical silica, trade name SC2500 (manufactured by Admatechs Co., Ltd.), average particle size 0.5 μm Weighed the (A) component and (B) component into a stirring container, further added the (C) component, and stirred with a mixer for 30 minutes. Then, added the (D) component, (E) component, and (F) component, and stirred for 10 minutes. The ratios (unit: parts by mass) of each component contained in the epoxy resin compositions of each example and comparative example are as shown in Table 1. Note that the blanks in Table 1 indicate that the corresponding components were not added. The following tests (evaluations) were all conducted under an environment of 25°C.

[0107] <Test (Evaluation)> [Viscosity] Regarding the viscosity of the obtained epoxy resin composition, using a cone and plate viscometer, under an environment of 25°C and 55% RH, the shear rate was 10 s -1 It was measured at. The passing criterion is 2000 mPa·s or less. Considering workability, it is preferably 1500 mPa·s or less, and more preferably 600 mPa·s or less.

[0108] [Shear Adhesion Strength] Applied each epoxy resin composition to a test piece of SUS304 (25×100×1.0 mm, linear expansion coefficient 18×10 -6 / K), and pasted a test piece of each of the following plastic materials on it, and fixed it with a clamp. At this time, the adhesion area of the test piece of each plastic material was made 25×10 mm. It was cured in a hot air drying oven at 80°C for 60 minutes to obtain a cured product. After returning the cured product to room temperature, using a tensile testing machine, in accordance with JIS K 6850:1999, the shear adhesion strength (unit: MPa) was measured at a tensile speed of 50 mm / min.

[0109] (Plastic Material) 6-nylon (25×100×1.5 mm), linear expansion coefficient 8×10 -5 / K 6,6-Nylon (25 x 100 x 1.5 mm) Coefficient of linear expansion: 10 x 10 -5 / K PBT (Polybutylene Terephthalate) (25 x 100 x 1.5 mm) Coefficient of linear expansion: 2.5 x 10 -5 / K ABS (Acrylonitrile-butadiene-styrene copolymer) (25 x 100 x 1.5 mm) Coefficient of linear expansion: 8 x 10 -5 / K GFRP (Glass Fiber Reinforced Plastic) (25 x 100 x 1.5 mm) Coefficient of linear expansion: 5.8 x 10 -5 / K.

[0110] [Hardening shrinkage rate] Each epoxy resin composition was dropped 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. Next, the curing shrinkage rate was determined by the following method.

[0111] (Method for calculating hardening shrinkage rate) The specific gravity of the uncured epoxy resin composition is determined by the specific gravity cup method (S g1 The mass of the hardened material in air (WA) and in water (distilled water) (WB) was measured. g2 The specific gravity of the hardened material (S) is calculated using the formula =WA / (WA-WB). g2 The specific gravity (S) of the uncured composition obtained above was determined. g1 ) and the specific gravity of the cured product (S g2 ) From this, ΔV={(S g2 -S g1 ) / S g2 The curing shrinkage rate (ΔV) calculated using the formula} × 100 was defined as the curing shrinkage rate.

[0112] (Pass criteria) Hardening shrinkage rate of 5.0% or less.

[0113] [Table 1]

[0114] As shown in the above tests, the epoxy resin compositions of the examples can be cured by heating at 80°C for 60 minutes and exhibit good adhesive strength (high shear bond strength). Thus, since curing is possible at temperatures below 100°C, it has been confirmed that the epoxy resin compositions of the examples have excellent low-temperature curing properties.

[0115] In evaluating shear bond strength, as shown in Table 1, the epoxy resin compositions of Examples 1 to 3 showed good shear bond strength in all combinations of test specimens compared to Comparative Example 1, which did not contain component (B). Furthermore, the epoxy resin compositions of Examples 1 to 3 also showed low curing shrinkage rates. In addition, the epoxy resin compositions of Examples 1 to 3 had low viscosity, and the compositions of Examples 1 and 3 showed particularly low viscosity.

[0116] From the above, it can be seen that the epoxy resin composition according to the present invention, by containing components (A) to (E), can exhibit good adhesion to dissimilar materials. In addition, it can be seen that the epoxy resin composition according to the present invention has good low-temperature curing properties, low viscosity, and excellent curing shrinkage properties. [Industrial applicability]

[0117] The epoxy resin composition according to the present invention has excellent adhesion to dissimilar materials. Furthermore, the epoxy resin composition according to the present invention has low curability and low viscosity for good workability, and also has low curing shrinkage, making it very useful as an adhesive, coating agent, and potting agent for use in various components.

[0118] This application is based on Japanese Patent Application No. 2020-161114, filed on September 25, 2020, the disclosures of which are referenced and incorporated in whole.

Claims

1. An epoxy resin composition comprising the following components (A) to (E), wherein the content of component (B) is 1 to 100 parts by mass per 100 parts by mass of component (A): (A) 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. (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 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) Thiol curing agent (D) Latent curing agent (E) Reactive diluent; Here, component (B) includes component (B-1), The (D) component is one or more selected from fine powders of compounds having an imidazole skeleton and fine powders of epoxy adduct compounds. The ratio of the total functional group equivalents of components (A) and (B) to component (C) ({functional group equivalents of component (A) + functional group equivalents of component (B)} / functional group equivalents of component (C)) is between 0.1 and 0.

60.

2. The epoxy resin composition according to claim 1, wherein the component (A) is a bisphenol-type epoxy resin.

3. The epoxy resin composition according to claim 1 or 2, wherein the component (B) is a bisphenol-type epoxy resin and / or a biphenyl-type epoxy resin.

4. The epoxy resin composition according to any one of claims 1 to 3, wherein the (C) component is a compound having 3 or more SH groups.

5. The epoxy resin composition according to any one of claims 1 to 4, wherein the content of component (C) is 50 to 300 parts by mass per 100 parts by mass of component (A).

6. The epoxy resin composition according to any one of claims 1 to 5, wherein the content of component (E) is 50 to 120 parts by mass with respect to 100 parts by mass of the total of components (A) and (B).

7. The epoxy resin composition according to any one of claims 1 to 6, further comprising (F) an inorganic filler.

8. The epoxy resin composition according to any one of claims 1 to 7, wherein the average particle size of component (D) is 0.1 to 50 μm.

9. The epoxy resin composition according to any one of claims 1 to 8, wherein the curing shrinkage rate is 5% or less.

10. An epoxy resin composition according to any one of claims 1 to 9, used for bonding and / or sealing between adherends having different coefficients of thermal expansion.

11. A cured product of the epoxy resin composition according to any one of claims 1 to 10.

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