Method for dismantling bonded body

Abstract

Provided is a method for dismantling a bonded body having excellent adhesive properties, flexibility and dismantlability. Specifically the present invention is a method for dismantling a bonded body in which a base material A and a base material B are bonded by means of an adhesive layer. The adhesive layer has a phase separated structure. The method includes a heating step for subjecting the bonded body to induction heating or microwave heating. The adhesive layer is a cured product of an epoxy resin composition. The phase separated structure is produced by curing the epoxy resin composition. The epoxy resin composition preferably contains: an epoxy resin (A) having a specific structure and having an epoxy equivalent weight of 500-10,000 g / eq; and an epoxy resin (B) having an epoxy equivalent weight of 100-300 g / eq.

Description

How to disassemble the adhesive

[0001] The present invention relates to a method for dismantling an adhesive body.

[0002] CO ２ Automobiles and airplanes are becoming increasingly lighter due to factors such as reductions in fuel consumption and improvements in fuel efficiency. This has led to weight reductions through measures such as reducing the number of spot welds and using fiber-reinforced resins in combination with metals, and there is a strong demand for high adhesive performance in the structural adhesives used in these applications.

[0003] On the other hand, achieving high adhesive performance has led to the creation of products that are difficult to recycle, limiting their dismantling and reusability after use. With the recent rise in environmental awareness, it is also important to develop adhesives that maintain high adhesive performance while being easily removable after a period of use.

[0004] Against this background, the development of easily dismantlable adhesives has been actively pursued. Generally, the thermal melting of thermoplastic resins is utilized, but research into the use of thermosetting resins in combination with thermal expansion materials is also being actively pursued. Furthermore, a temporary bonding method using a UV-curable adhesive for temporary bonding during processing of optical glass, wafers, etc., in which the adhesive is peeled off by microwave irradiation has been reported (see, for example, Patent Document 1).

[0005] Japanese Patent Application Laid-Open No. 2021-120428

[0006] However, conventional technologies such as those in Patent Document 1 still have problems such as "the effect of thermal expansion cannot be obtained," "the adhesive is hard and brittle and lacks flexibility," and "as a result of emphasizing flexibility, sufficient adhesive strength cannot be obtained." Furthermore, issues associated with dismantling operations include the need to prevent damage to the bonded materials and to minimize the environmental impact of the dismantling process. An object of the present invention is to provide a method for dismantling an adhesive structure that has excellent adhesiveness, flexibility, and dismantlability.

[0007] As a result of extensive research, the present inventors have discovered that the above problems can be solved by using an adhesive having a phase separation structure and heating it with induction heating or microwaves, and have completed the invention.

[0008] That is, the present invention encompasses the following aspects. [1] A method for dismantling an adhered body in which substrate A and substrate B are bonded via an adhesive layer, wherein the adhesive layer has a phase-separated structure, and the method for dismantling an adhered body comprises a heating step of inductively heating or microwave heating the adhered body. [2] The method for dismantling an adhered body according to [1], wherein the adhesive layer is a cured product of an epoxy resin composition, and the phase-separated structure is formed by curing the epoxy resin composition, and the epoxy resin composition contains an epoxy resin (A) represented by the following general formula (1) and having an epoxy equivalent of 500 to 10,000 g / equivalent, and an epoxy resin (B) having an epoxy equivalent of 100 to 300 g / equivalent:

[0009] [In formula (1), each Ar independently represents a structure having an unsubstituted or substituted aromatic ring, X represents a structural unit represented by the following general formula (2), and Y represents a structural unit represented by the following general formula (3):

[0010] [In formulas (2) and (3), Ar is the same as above, and R １ , R ２ are each independently a hydrogen atom, a methyl group, or an ethyl group; R' is a divalent hydrocarbon group having 2 to 12 carbon atoms; R ３ , R ４ , R ７ , R ８ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R ５ , R ６ , R ９ , R １０ are each independently a hydrogen atom or a methyl group, n1 is an integer of 4 to 16, and n2 is the average number of repeating units of 2 to 30.] R １１ , R １２ are each independently a glycidyl ether group or a 2-methylglycidyl ether group, and R １３ , R １４ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R １５ , R １６represents a hydrogen atom or a methyl group, m1, m2, p1, p2, and q represent the average value of the repeating units, m1 and m2 are each independently 0 to 25 and m1+m2≧1, p1 and p2 are each independently 0 to 5, and q is 0.5 to 5. However, the bond between X represented by general formula (2) and Y represented by general formula (3) may be random or block, and the total number of structural units X and Y present in one molecule is m1 and m2, respectively. [3] The method for dismantling a bonded body according to [2], wherein the mass ratio (A):(B) of the epoxy resin (A) to the epoxy resin (B) is 90:10 to 10:90. [4] The method for dismantling a bonded body according to [2] or [3], wherein the epoxy resin composition further contains a heterocyclic aromatic compound (C) having a tertiary amino group. [5] The method for dismantling a bonded body according to [4], wherein the heterocyclic aromatic compound (C) having a tertiary amino group is at least one compound selected from the group consisting of imidazole compounds and pyridine compounds having a tertiary amino group. [6] The method for dismantling a bonded body according to [4] or [5], wherein the heterocyclic aromatic compound (C) having a tertiary amino group is at least one compound selected from the group consisting of imidazole, 1-methylimidazole, 2-ethyl-4-methylimidazole, and 4-dimethylaminopyridine. [7] The method for dismantling a bonded body according to any one of [4] to [6], wherein the heterocyclic aromatic compound (C) having a tertiary amino group is used in an amount of 2 to 20 parts by mass per 100 parts by mass of the epoxy resin (A) and the epoxy resin (B). [8] The method for dismantling a bonded body according to any one of [2] to [7], wherein the epoxy resin composition further contains thermally expandable particles (D). [9] The method for dismantling a bonded body according to [8], wherein the thermally expandable particles (D) are at least one selected from the group consisting of thermally expandable microcapsules and expandable graphite.

[10] The method for dismantling a bonded body according to [8] or [9], wherein the proportion of the thermally expandable particles (D) used is within a range of 3 to 40 parts by mass per 100 parts by mass of the total of the epoxy resin (A) and the epoxy resin (B).

[11] The method for dismantling adhesive-bonded bodies according to any one of [2] to

[10] , wherein the epoxy resin composition further comprises a glycidyl ether group-containing compound (E), wherein the glycidyl ether group-containing compound (E) is a compound formed by linking a structural unit V having one or more glycidyl ether groups with a structural unit W different from the structural unit V via a V-W-V bond, and wherein the structural unit V and the structural unit W are bonded by a reversible bond formed by a Diels-Alder reaction between a furan structure and a maleimide structure.

[12] The method for dismantling adhesive-bonded bodies according to

[11] , wherein the glycidyl ether group-containing compound (E) is a compound represented by the following general formula (4) and has a molecular weight of less than 1,000:

[0011] [In formula (4), m3 is an integer of 1 to 4. Z １ is the following formula (5), Z ３ is any of the structures represented by the following formula (6), and a plurality of such structures in one molecule may be the same or different.

[0012] [In formula (5), the aromatic ring may be unsubstituted or may have a substituent, * represents a bonding point, and G represents a glycidyl group or a 2-methylglycidyl group.]

[0013] (In formula (6), each R" is independently a hydrogen atom, a methyl group, or an ethyl group, w1 is an integer of 1 to 30, w2 is the average number of repeats and is 0.5 to 8, w3 is the average number of repeats and is 0.5 to 6, and * represents a bonding point.)

[13] The method for dismantling an adhered body according to any one of [2] to

[12] , wherein the epoxy resin composition further contains a curing agent (F).

[14] The method for dismantling an adhered body according to any one of [2] to

[13] , wherein the phase-separated structure comprises resin particles having an average particle size of 10 nm to 100 μm and a matrix surrounding the resin particles, wherein the resin particles contain a cured product of the epoxy resin (A), and the matrix contains a cured product of the epoxy resin (B).

[15] The method for dismantling an adhered body according to any one of [2] to

[13] , wherein the phase-separated structure comprises resin particles having an average particle size of 10 nm to 100 μm and a matrix surrounding the resin particles, wherein the resin particles contain a cured product of the epoxy resin (A), and the matrix contains a cured product of the epoxy resin (B). The method for dismantling an adhesive body according to any one of [2] to

[13] , wherein the resin particles contain a cured product of the epoxy resin (B), and the matrix contains a cured product of the epoxy resin (A).

[0014] According to the present invention, a method for dismantling an adhered body that is excellent in adhesiveness, flexibility, and dismantling ability can be provided by using an adhesive having a phase separation structure and heating with induction heating or microwaves.

[0015] Next, embodiments for carrying out the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be embodied in various forms with various improvements, modifications, and variations based on the knowledge of those skilled in the art, without departing from the spirit of the present invention, and all of these forms belong to the scope of the present invention. In this specification, numerical ranges indicated using "to" indicate ranges that include the numerical values ​​written before and after "to" as the minimum and maximum values, respectively. Furthermore, unless specifically stated otherwise, the units of the numerical values ​​written before and after "to" are the same. Furthermore, individually stated upper and lower limit values ​​can be arbitrarily combined.

[0016] [Method for dismantling bonded body] A method for dismantling a bonded body as one aspect (present embodiment) of the present invention (sometimes simply referred to as the "dismantling method of this embodiment") is a method for dismantling a bonded body in which substrate A and substrate B are bonded via an adhesive layer. The adhesive layer has a phase-separated structure. The dismantling method of this embodiment is a method for dismantling a bonded body, which includes a heating step of inductively heating or microwave heating the bonded body. It is preferable that the adhesive layer is a cured product of an epoxy resin composition, and that the phase-separated structure is generated by curing the epoxy resin composition.

[0017] (Induction Heating) The induction heating used in the disassembly method of this embodiment is preferably electromagnetic induction heating. Electromagnetic induction heating is performed by applying an alternating magnetic field of a predetermined frequency to the components. This generates eddy currents in the components (mainly conductive parts such as metals) that resist changes in magnetic flux, causing Joule heating. The higher the frequency of the alternating magnetic field, the more easily the component surfaces (adhesion interfaces) are heated due to the skin effect. Electromagnetic induction heating is superior to other heating methods in that it can rapidly heat non-contact areas.

[0018] The adhesive interface is preferably made of a conductor, and the conductor is preferably directly heated by electromagnetic induction. The conductor constituting the adhesive interface may be heated by electromagnetic induction from a position and direction that is easy to work with, depending on the shape and size of the adhesive, the specifications of the electromagnetic induction heating device, the shape of its heating coil, etc.

[0019] Electromagnetic induction heating is preferably performed by applying an alternating magnetic field having a frequency (for example, about 100 to 500 kHz, or even about 300 to 400 kHz) higher than the general frequency (5 to 30 kHz).

[0020] The frequency (f) of the alternating magnetic field is usually preferably close to the resonant (angular) frequency (f0) of the high-frequency power supply circuit. The high-frequency power supply circuit may be a series resonant circuit or a parallel resonant circuit, but in either case, f0 = (LC) -1 / 2 / 2π is preferably satisfied. L and C are the self-inductance of the coil (mainly the heating coil) and the capacitance of the capacitor in the high-frequency power supply circuit, respectively.

[0021] When the frequency of the alternating magnetic field is close to the resonant frequency, the power supplied from the electromagnetic induction coil (simply referred to as the "heating coil") is maximized. Therefore, it is preferable that the heating coil and the capacitor in the power supply circuit are selected or matched so that the desired resonant frequency is obtained. It is preferable that the frequency of the alternating magnetic field be within ±20%, or even ±10%, of the resonant frequency determined by the high-frequency power supply circuit (high-frequency power supply, coil, capacitor, and resistor).

[0022] Conductors that are heated by electromagnetic induction should have high magnetic permeability and electrical conductivity, and low thermal conductivity, which causes the temperature of the heated area to rise rapidly, making it easier for shock thermal stress to act on the adhesive interface.

[0023] When the conductor constituting the adhesive interface is heated by electromagnetic induction, the conductor may be a magnetic material, such as an iron substrate (pure iron, iron alloy, composite material, etc.). When the conductor is a magnetic material (particularly an iron substrate), the heating rate may be, for example, 16°C / sec or more, 18°C / sec or more, or even 20°C / sec or more. The heating rate (ΔT / t) is the average time change rate of temperature obtained by dividing the temperature change (ΔT) on the first component (mainly the conductor) side from the start of electromagnetic induction heating to the separation (peel) of the adhesive interface by the time (t) required from the start of the heating to the separation (peel) (the same applies below).

[0024] Even if the conductor is non-magnetic, the bonded structure can be dismantled using the treatment method of the present invention. Non-magnetic materials include, for example, aluminum or copper substrates. Because such conductors have a large thermal expansion coefficient, significant thermal stress can occur at the adhesive interface without the need for heating, as with iron substrates. When the conductor is non-magnetic (particularly aluminum substrates), the heating rate should be 2°C / sec or higher, 4°C / sec or higher, or even 6°C / sec or higher. Furthermore, carbon substrates and carbon fiber-reinforced plastics (CFRP) containing carbon fibers are also conductive and can be heated by electromagnetic induction. A magnetic material that is easily heated by electromagnetic induction may be placed near the conductor to assist heating of the conductor via thermal conduction or heat transfer.

[0025] The electromagnetic induction heating according to this embodiment is not particularly limited as long as it can heat any of the layers of the adhesive body (substrate A, adhesive layer, substrate B). The content of the material capable of being subjected to electromagnetic induction heating in any of the layers of the adhesive body is not particularly limited as long as it is an amount that can heat the adhesive layer. When electromagnetic induction heating is used in the disassembly method of this embodiment, it is preferable that at least one layer of substrate A and substrate B is a conductor.

[0026] (Microwave Heating) [Microwave Heatable Materials] The microwave heating used in the disassembly method of this embodiment preferably uses electromagnetic waves of 300 MHz to 300 GHz. Microwave heating is a method of heating an object by generating heat through molecular motion and ionic conduction of the object due to the action of electromagnetic waves of 300 MHz to 300 GHz. Therefore, while it is possible to heat dielectric, conductive, and magnetic materials, it is primarily suitable for heating dielectric materials. Examples of the dielectric include various synthetic resins; ceramics such as silicon carbide and silicon nitride; and mica. Examples of the conductive material include metal materials and conductive nonmetallic materials similar to the materials capable of electromagnetic induction heating. Examples of the magnetic material include iron oxide and various ferrite materials.

[0027] The microwave heating according to this embodiment is not particularly limited as long as it can heat any of the layers of the adhesive structure (substrate A, adhesive layer, substrate B). The content of the microwave-heatable material in any of the layers of the adhesive structure is not particularly limited as long as it is an amount that can heat the adhesive layer. When microwave heating is used in the disassembly method of this embodiment, it is preferable that at least one layer of substrate A, adhesive layer, and substrate B contains a dielectric, and more preferably is a dielectric.

[0028] (Adhesive Body) The adhesive body includes the substrate A, the substrate B, and the adhesive layer, and the substrate A and the substrate B are adhered to each other via the adhesive layer.

[0029] The materials of the substrates A and B as the adherends are not particularly limited, and examples thereof include inorganic materials such as metal and glass, organic materials such as plastic and wood, fiber-reinforced resins such as CFRP, CFRTP, GFRP, GFRTP, etc. These materials may be used appropriately depending on the application.

[0030] The substrate A and the substrate B may be made of the same material or different materials. Because the adhesive layer can relieve stress, there are applications in which the substrate A and the substrate B are preferably made of different materials. For example, even if the substrate is made of a metal and / or metal oxide and the second substrate is made of a different material such as a plastic layer, the adhesive strength is maintained due to the stress relief ability of the adhesive layer.

[0031] Examples of the metal include copper, aluminum, gold, silver, iron, platinum, chromium, nickel, tin, titanium, zinc, various alloys, and composite materials thereof, and examples of the metal oxide include single oxides and / or composite oxides of these metals. Iron, copper, and aluminum are preferred as the metal because they have excellent adhesive strength to the adhesive layer, particularly to iron, copper, and aluminum.

[0032] The shapes of the substrate A and the substrate B may be any shape depending on the purpose. For example, they may be flat, sheet-like, or have a three-dimensional structure. Furthermore, they may have a curvature over the entire surface or a part of the surface. The shapes of the substrate A and the substrate B may be any shape depending on the purpose.

[0033] The hardness, thickness, etc. of the substrate A and the substrate B are not particularly limited.

[0034] <Method of Forming Adhesive> In the adhesive of this embodiment, any adhesive may be used as long as it exhibits a phase-separated structure. For example, the crosslinkable composition described in Japanese Patent No. 7435920 can be used. Among these, it is preferable to use the epoxy resin composition described below. The adhesive layer may be formed by direct coating or molding on the substrate A (or substrate B), or by laminating an already molded adhesive layer. When directly coating, the coating method is not particularly limited, and examples thereof include spraying, spin coating, dipping, roll coating, blade coating, doctor roll coating, doctor blade coating, curtain coating, slit coating, screen printing, and inkjet printing. When directly molding, examples thereof include in-mold molding, insert molding, vacuum molding, extrusion lamination molding, and press molding. When laminating a molded composition, an uncured or semi-cured composition layer may be laminated and then cured, or a layer containing a completely cured cured product of the composition may be laminated on the substrate A (or substrate B).

[0035] As described above, the adhesive layer is preferably a cured product of an epoxy resin composition. The epoxy resin composition and the cured product thereof will be described in detail below.

[0036] (Epoxy Resin Composition) The epoxy resin composition contains an epoxy resin (A) represented by the above general formula (1) and having an epoxy equivalent of 500 to 10,000 g / equivalent, an epoxy resin (B) having an epoxy equivalent of 100 to 300 g / equivalent, and, if necessary, a heterocyclic aromatic compound (C) having a tertiary amino group and thermally expandable particles (D).

[0037] The epoxy resin composition according to this embodiment preferably further contains a glycidyl ether group-containing compound (E). The glycidyl ether group-containing compound (E) is a compound formed by linking a structural unit V having one or more glycidyl ether groups and a structural unit W different from the structural unit V via the V-W-V bond. The structural unit V and the structural unit W are bonded via a reversible bond formed by a Diels-Alder reaction between a furan structure and a maleimide structure.

[0038] The epoxy resin composition according to this embodiment preferably further contains a curing agent (F). The epoxy resin composition according to this embodiment may optionally contain an epoxy resin other than the epoxy resin (A), the epoxy resin (B), and the glycidyl ether group-containing compound (E) according to this embodiment. The epoxy resin composition according to this embodiment may also optionally contain a curing accelerator, other thermosetting resins or thermoplastic resins, a non-halogen flame retardant, a filler not belonging to the thermally expandable particles (D) according to this embodiment, or a dispersion medium. The total chlorine content of the epoxy resin composition according to this embodiment is preferably 0.001 to 5% by mass, more preferably 0.001 to 3% by mass, and even more preferably 0.01 to 2% by mass. The total chlorine content of the epoxy resin composition can be measured in the same manner as the total chlorine content of the epoxy resin (A) described below. For example, the measurement method described in the Examples section below can be used. Each component is described in detail below.

[0039] [Epoxy resin (A)]

[0040] The epoxy resin (A) contained in the epoxy resin composition according to this embodiment is an epoxy resin represented by the following general formula (1) and having an epoxy equivalent of 500 to 10,000 g / equivalent.

[0041] [In formula (1), each Ar independently represents a structure having an unsubstituted or substituted aromatic ring, X represents a structural unit represented by the following general formula (2), and Y represents a structural unit represented by the following general formula (3):

[0042]

[0043] [In formulas (2) and (3), Ar is the same as above, and R １ , R ２ are each independently a hydrogen atom, a methyl group, or an ethyl group; R' is a divalent hydrocarbon group having 2 to 12 carbon atoms; R ３ , R ４ , R ７ , R ８are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R ５ , R ６ , R ９ , R １０ are each independently a hydrogen atom or a methyl group, n1 is an integer of 4 to 16, and n2 is the average number of repeating units of 2 to 30.] R １１ , R １２ are each independently a glycidyl ether group or a 2-methylglycidyl ether group, and R １３ , R １４ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R １５ , R １６ represents a hydrogen atom or a methyl group, m1, m2, p1, p2, and q represent the average value of the repeating units, m1 and m2 are each independently 0 to 25 and m1+m2≧1, p1 and p2 are each independently 0 to 5, and q is 0.5 to 5. However, the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total number of structural units X and Y present in one molecule is m1 and m2, respectively.

[0044] The above structure contains the structural unit X represented by general formula (2) and / or the structural unit Y represented by general formula (3), and the presence of the alkylene chain or polyether chain in each structural unit makes it possible to impart high flexibility to the cured product. In particular, the flexibility derived from the alkylene chain enables the epoxy resin (A) to follow the thermal expansion of the substrate when it is cured, and the polyether chain reduces the viscosity of the epoxy resin (A) itself, thereby contributing to improved processability and coatability of the epoxy resin composition.

[0045] The epoxy resin (A) may have each of the structural units X and Y singly, or may have both the structural units X and Y in one molecule. In this case, X and Y may be bonded in a block bond or a random bond, and the total number of the structural units X and Y contained in one molecule is m1 and m2, respectively.

[0046] Ar in general formula (1) representing the epoxy resin (A), Ar in general formula (2) representing the structural unit X, and Ar in general formula (3) representing the structural unit Y all have a structure having an unsubstituted or substituted aromatic ring. The aromatic ring is not particularly limited, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and a fluorene ring.

[0047] Among these, Ar is preferably any of the structures represented by the following structural formula (ar).

[0048] [The aromatic ring in formula (ar) may be unsubstituted or substituted, and * represents a point of attachment. The point of attachment is located on the aromatic ring, and when the structure contains multiple aromatic rings, the point of attachment may be located on the same aromatic ring or on different aromatic rings.]

[0049] Further, structures represented by the following formulas are also included as Ar.

[0050] (In the formula, the aromatic ring may be unsubstituted or may have a substituent, and n ３ = 1 to 4, and * represents a bonding point.)

[0051] The aromatic ring of Ar may be unsubstituted or substituted. When Ar has a substituent, preferred examples of the substituent include an alkyl group, a halogen atom, a glycidyl ether group, and a 2-methylglycidyl ether group. Preferred are unsubstituted groups, alkyl groups, glycidyl ether groups, and 2-methylglycidyl ether groups. The number of substituents per aromatic ring is preferably two or less, more preferably one or less, and particularly preferably unsubstituted.

[0052] The following structures are particularly preferred for Ar: * represents a bonding point.

[0053]

[0054] Particularly preferred structures for Ar having a substituent include the following structures: * represents a bonding point.

[0055]

[0056] In the above formula, each R is independently a hydrogen atom or a methyl group.

[0057] In the structural unit X represented by the general formula (2), the repeating unit n1 is an integer of 4 to 16. When n1 is 4 or more, the adhesive strength is improved and the deformation mode of the cured product is elastic deformation, which is preferable. Furthermore, when n1 is 16 or less, a decrease in crosslink density can be suppressed, which is preferable. With regard to n1, 4 to 15 is more preferable, and 6 to 12 is even more preferable.

[0058] Among these, R ３ , R ４ is preferably a hydroxyl group, and R ５ , R ６ is preferably a hydrogen atom.

[0059] In the structural unit Y represented by the general formula (3), n2 is the average value of the repeating units and is 2 to 30. Being within this range is preferable in terms of achieving a good balance between the viscosity of the epoxy resin (A) and the crosslink density of the resulting cured product. n2 is more preferably 2 to 25, and even more preferably 4 to 20.

[0060] In the structural unit Y represented by the general formula (3), R' is a divalent hydrocarbon group having 2 to 12 carbon atoms. Within this range, the adhesive strength is improved and the deformation mode of the cured product can be elastic. R' is preferably a divalent hydrocarbon group having 2 to 6 carbon atoms.

[0061] The divalent hydrocarbon group is not particularly limited, and examples thereof include linear or branched alkylene groups, alkenylene groups, alkynylene groups, cycloalkylene groups, arylene groups, and aralkylene groups (divalent groups having an alkylene group and an arylene group).

[0062] Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. Examples of the alkenylene group include a vinylene group, a 1-methylvinylene group, a propenylene group, a butenylene group, and a pentenylene group. Examples of the alkynylene group include an ethynylene group, a propynylene group, a butynylene group, a pentynylene group, and a hexynylene group. Examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group. Examples of the arylene group include a phenylene group, a tolylene group, a xylylene group, and a naphthylene group.

[0063] Among these, ethylene, propylene and tetramethylene groups are preferred from the viewpoints of availability of raw materials, viscosity of the resulting epoxy resin (A), and balance of adhesiveness and flexibility of the resulting cured product.

[0064] In the structural unit Y represented by the general formula (3), R ７ , R ８ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R ９ , R １０ are each independently a hydrogen atom or a methyl group. ７ , R ８ is preferably a hydroxyl group, and R ９ , R １０ is preferably a hydrogen atom.

[0065] As described above, the epoxy resin (A) used in this embodiment is represented by the general formula (1). In the general formula (1), m1 and m2 are the average values ​​of the repeating numbers of the structural unit X and the structural unit Y, respectively, and are each independently 0 to 25, and m1+m2≧1.

[0066] In addition, R in the general formula (1) １１ , R １２ are each independently a glycidyl ether group or a 2-methylglycidyl ether group, and R １３ , R １４ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R １５ , R １６ are each independently a hydrogen atom or a methyl group, p1, p2, and q are the average values ​​of the repeating groups, p1 and p2 are each independently 0 to 5, and q is 0.5 to 5. １１ , R １２ is preferably a glycidyl ether group, and R １３ , R １４ is preferably a hydroxyl group, and R １５ , R １６ is preferably a hydrogen atom. Furthermore, p1 and p2 are preferably 0 to 2, and q is preferably 0.5 to 2.

[0067] Furthermore, the epoxy equivalent of the epoxy resin (A) used in this embodiment is 500 to 10,000 g / equivalent. By keeping it within this range, the resulting cured product will have excellent adhesion, flexibility, and dismantling properties. Taking ease of handling into consideration, it is preferably in the range of 600 to 8,000 g / equivalent, more preferably in the range of 800 to 5,000 g / equivalent, and even more preferably in the range of 800 to 4,000 g / equivalent.

[0068] Among the epoxy resins (A) of the present embodiment, examples of resins having both the structural unit X and the structural unit Y in one molecule include resins having the following structural formula: In the structural formula written in two lines, * indicates a bonding point.

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081] In each of the structural formulas (A-1) to (A-12), ran represents a random bond, G represents a glycidyl group or a 2-methylglycidyl group, R' represents a divalent hydrocarbon group having 2 to 12 carbon atoms, n11 is an integer from 4 to 16, n21 represents the average value of the repeating units and is 2 to 30, m11, m21, p11, p21, and q11 represent the average value of the repeating units, m11 and m21 each independently represent 0.5 to 25, p11 and p21 each independently represent 0 to 5, and q11 represents 0.5 to 5. However, each repeating unit present in the repeating unit may be the same or different.

[0082] Among the above structural formulas, those represented by structural formulas (A-1), (A-2), (A-3), (A-5), (A-7), (A-8) and (A-9) are preferably used, from the viewpoint of excellent adhesiveness, flexibility and dismantling properties of the resulting cured epoxy resin product.

[0083] Among the epoxy resins (A), examples of the epoxy resins having the structural unit X include resins represented by the following structural formulas.

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096] In each of the structural formulas (A-13) to (A-24), G is a glycidyl group or a 2-methylglycidyl group, n11 is an integer of 4 to 16, m11, p11, p21, and q11 are the average values ​​of the repeating units, m11 is 0.5 to 25, p11 and p21 are each independently 0 to 5, and q11 is 0.5 to 5. However, each repeating unit present in the repeating unit may be the same or different.

[0097] Among the above structural formulas, those represented by structural formulas (A-13), (A-14), (A-15), (A-17), (A-19), (A-20), and (A-21) are preferably used, in view of the excellent adhesiveness, flexibility, and dismantling properties of the resulting cured epoxy resin product.

[0098] Among the epoxy resins (A), examples of the epoxy resins having the structural unit Y include resins represented by the following structural formulas.

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111] In each of the structural formulas (A-25) to (A-36), G is a glycidyl group or a 2-methylglycidyl group, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms, n21 is the average value of the repeating units and is 2 to 30, m21, p11, p21, and q11 are the average values ​​of the repeating units, m21 is 0.5 to 25, p11 and p21 are each independently 0 to 5, and q11 is 0.5 to 5. However, the repeating units present in the repeating units may be the same or different from each other.

[0112] Among the above structural formulas, those represented by structural formulas (A-25), (A-26), (A-27), (A-29), (A-31), (A-32) and (A-33) are preferably used, in view of the excellent adhesiveness, flexibility and dismantling properties of the resulting cured epoxy resin product.

[0113] <Method for producing epoxy resin (A)> The method for producing the epoxy resin (A) according to this embodiment is not particularly limited, but a method of reacting a diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain and / or a polyether chain, an aromatic hydroxy compound (a2), and an epihalohydrin (a3) ​​is preferred from the viewpoints of ease of obtaining raw materials and the ease of reaction. The epoxy resin may be produced by a method in which all of the reaction raw materials are reacted at once, or the resin may be produced by a method in which the reaction raw materials are reacted sequentially. The method in which the reaction raw materials are reacted sequentially is preferred from the viewpoints of excellent adhesion, flexibility, and dismantling properties of the resulting epoxy resin cured product.

[0114] Examples of the method of sequentially reacting the reaction raw materials include a method in which a diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain is reacted with an aromatic hydroxy compound (a2) in a molar ratio (a1) / (a2) of 1 / 1.01 to 1 / 5.0 to obtain a hydroxy compound (a12) [corresponding to a precursor or intermediate of the epoxy resin (A)], which is then reacted with an epihalohydrin (a3). The "molar ratio (a1) / (a2)" is the molar ratio of the epoxy group in the diglycidyl ether (a1) to the phenolic hydroxy group (hydroxy group bonded to an aromatic ring) in the aromatic hydroxy compound (a2).

[0115] In order to ensure excellent adhesion, flexibility, and dismantling properties of the resulting epoxy resin cured product, the viscosity of the epoxy resin (A) at 60°C is preferably 1,000 mPa·s to 1,000,000 mPa·s, more preferably 2,000 mPa·s to 700,000 mPa·s, and even more preferably 5,000 mPa·s to 500,000 mPa·s. The total chlorine content is preferably 0.001 to 20% by mass, more preferably 0.001 to 15% by mass, and even more preferably 0.01 to 10% by mass. The epoxy equivalent, viscosity, and total chlorine content of the epoxy resin (A) are measured by the methods described in the Examples below.

[0116] The product obtained by the reaction of the diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain with the aromatic hydroxy compound (a2) may contain unreacted aromatic hydroxy compound (a2), but in the synthesis of the epoxy resin (A) used in this embodiment, the product may be directly subjected to the reaction with the epihalohydrin (a3), which is the next step, or the unreacted aromatic hydroxy compound (a2) may be removed. However, from the viewpoint of the balance between toughness and flexibility of the cured product obtained from the epoxy resin composition according to this embodiment containing the resulting epoxy resin (A), it is preferable that the abundance of unreacted aromatic hydroxy compound (a2) in the hydroxy compound to be subjected to the next step is within the range of 0.1 to 30% by mass.

[0117] The method for removing the unreacted aromatic hydroxy compound (a2) is not particularly limited, and can be carried out according to various methods. For example, column chromatography separation utilizing the difference in polarity, fractional distillation utilizing the difference in boiling point, alkaline aqueous extraction utilizing the difference in solubility in alkaline water, etc. can be mentioned. Among them, alkaline aqueous extraction is preferred in terms of yield, etc., since it does not involve thermal deterioration. In this case, the organic solvent used to dissolve the target substance is preferably one that is immiscible with water, such as toluene, methyl isobutyl ketone, or butyl acetate, and methyl isobutyl ketone is particularly preferred in terms of solubility with the target substance.

[0118] The diglycidyl ether (a1) of the dihydroxy compound having an alkylene chain or a polyether chain is not particularly limited as long as it is a glycidyl ether of a "dihydroxy compound having an alkylene chain or a polyether chain." The reaction conditions for the glycidyl etherification reaction of the "dihydroxy compound having an alkylene chain or a polyether chain" are, for example, the same as the reaction conditions for the glycidyl etherification reaction of the hydroxy compound (a12) using the epihalohydrin (a3) ​​described below.

[0119] Examples of the diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain include diglycidyl ethers having an alkylene chain, such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, 1,11-undecanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, 1,13-trimethylolpropanediol diglycidyl ether, 1,14-trimethylolpropanediol diglycidyl ether, 1,15-trimethylolpropanediol diglycidyl ether, 1,16-trimethylolpropanediol diglycidyl ether, 1,17-trimethylolpropanediol diglycidyl ether, 1,18-trimethylolpropanediol diglycidyl ether, 1,19-trimethylolpropanediol diglycidyl ether, 1,20-trimethylolpropanediol diglycidyl ether, 1,21-trimethylolpropanediol diglycidyl ether, 1,22-trimethylolpropanediol diglycidyl ether, 1,23-trimethylolpropanediol diglycidyl ether, 1,24-trimethylolpropanediol diglycidyl ether, 1,25-trimethylolpropanediol diglycidyl ether, 1,26-trimethylolpropanediol diglycidyl ether, 1,27-trimethylolpropanediol diglycidyl ether, 1,28-trimethylolpropanediol diglycidyl ether, 1,29-trimethylolpropanediol diglycidyl ether, 1,30-trimethylolpropanediol diglycidyl ether, 1,31-trimethylolpropanediol diglycidyl ether, 1,3 Examples of the diglycidyl ether having a polyether chain include polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, polypentamethylene glycol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, and polyheptamethylene glycol diglycidyl ether. These may contain organic chlorine impurities produced during the glycidyl etherification of a hydroxy compound, or may contain organic chlorine such as 1-chloromethyl-2-glycidyl ether (chloromethyl form) represented by the following structure. These diglycidyl ethers may be used alone or in combination of two or more. The total chlorine content in the diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain is preferably 0.001 to 20% by mass, more preferably 0.001 to 15% by mass, and even more preferably 0.01 to 10% by mass.

[0120]

[0121] Among the above specific examples of the diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and polytetramethylene glycol diglycidyl ether are preferred, as they result in excellent adhesion, flexibility, and dismantling properties of the resulting cured product.

[0122] Furthermore, by simultaneously reacting the above-mentioned diglycidyl ether having an alkylene chain and the diglycidyl ether having a polyether chain with the aromatic hydroxy compound (a2), a hydroxy compound having both the structural unit X and the structural unit Y can be obtained, and by further reacting this with the epihalohydrin (a3), an epoxy resin (A) having both the structural unit X and the structural unit Y can be obtained.

[0123] The aromatic hydroxy compound (a2) is not particularly limited as long as it is a compound containing two or more phenolic hydroxyl groups, and examples thereof include dihydroxybenzenes such as hydroquinone, resorcinol, and catechol; trihydroxybenzenes such as pyrogallol, 1,2,4-trihydroxybenzene, and 1,3,5-trihydroxybenzene; triphenylmethane-type phenols such as 4,4',4"-trihydroxytriphenylmethane; 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, and 1,4-dihydroxynaphthalene. dihydroxynaphthalenes such as 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene; tetrafunctional phenols such as 1,1'-methylenebis-(2,7-naphthalenediol), 1,1'-binaphthalene-2,2',7,7'-tetraol, and 1,1'-oxybis-(2,7-naphthalenediol) obtained by coupling reaction of dihydroxynaphthalenes; bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, and 2,2-bis(3-methyl-4-hydroxyphenyl)propane; bisphenols such as 1,1-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 1,1-bis(4-hydroxyphenyl)-1-phenylethane, and bis(4-hydroxyphenyl)sulfone; 2,2'-biphenol, 4,4'-biphenol, (1,1'-biphenyl)-3,4-diol, 3,3'-dimethyl-(1,1'-biphenyl)-4,4'-diol, 3-methyl-(1,1'-biphenyl)-4,4'-diol, 3,3',5,5'-tetramethylbiphenyl-2,2'-diol, 3 Biphenols such as 1,3',5,5'-tetramethylbiphenyl-4,4'-diol, 5-methyl-(1,1'-biphenyl)-3,4'-diol, 3'-methyl-(1,1'-biphenyl)-3,4'-diol, and 4'-methyl-(1,1'-biphenyl)-3,4'-diol; alicyclic structure-containing phenols such as polyadducts of phenol and dicyclopentadiene and polyadducts of phenol and terpene compounds; naphthols such as bis(2-hydroxy-1-naphthyl)methane and bis(2-hydroxy-1-naphthyl)propane;Examples of suitable phenolic compounds include so-called Xylok-type phenolic resins, which are condensation reaction products of phenol and phenylene dimethyl chloride or biphenylene dimethyl chloride; phenol novolak resins, cresol novolak resins, dicyclopentadiene phenol addition type resins, phenol aralkyl resins (Xylok resins), naphthol aralkyl resins, trimethylolmethane resins, tetraphenylolethane resins, naphthol novolak resins, naphthol-phenol co-condensed novolak resins, naphthol-cresol co-condensed novolak resins, biphenyl-modified phenolic resins (polyhydric phenol compounds in which phenol nuclei are linked via bismethylene groups), biphenyl-modified naphthol resins (polyhydric naphthol compounds in which phenol nuclei are linked via bismethylene groups), aminotriazine-modified phenolic resins (polyhydric phenol compounds in which phenol nuclei are linked via melamine, benzoguanamine, or the like), and alkoxy group-containing aromatic ring-modified novolak resins (polyhydric phenol compounds in which phenol nuclei and alkoxy group-containing aromatic rings are linked via formaldehyde). These compounds may be used alone or in combination of two or more. Further examples include compounds in which the aromatic ring of each of the above compounds is substituted with a methyl group, a t-butyl group, or a halogen atom as a substituent. The alicyclic structure-containing phenols and the Xyloc-type phenolic resins may contain not only bifunctional components but also trifunctional or higher functional components. In the present invention, these may be used as they are, or only the bifunctional components may be isolated and used after a purification step such as a column purification step.

[0124] Among these, bisphenols are preferred because they provide excellent adhesion, flexibility, and dismantling properties to the resulting epoxy resin cured product, and bis(4-hydroxyphenyl)methane and 2,2-bis(4-hydroxyphenyl)propane are particularly preferred because they provide outstanding toughness. Furthermore, when emphasis is placed on the curability and heat resistance of the resulting epoxy resin cured product, dihydroxynaphthalenes are preferred, and 2,7-dihydroxynaphthalene is particularly preferred because it provides outstanding rapid curing properties. Furthermore, when emphasis is placed on the moisture resistance of the resulting epoxy resin cured product, it is preferable to use a compound containing an alicyclic structure.

[0125] From the viewpoint of reaction efficiency, the reaction ratio of the diglycidyl ether (a1) of the dihydroxy compound having an alkylene chain or a polyether chain to the aromatic hydroxy compound (a2) is preferably (a1) / (a2) from 1 / 1.01 to 1 / 5.0 (molar ratio), and more preferably (a1) / (a2) from 1 / 1.02 to 1 / 3.0 (molar ratio). The "molar ratio" is the molar ratio of epoxy groups to phenolic hydroxyl groups.

[0126] "Catalyst used in the reaction of (a1) and (a2)" The reaction of the diglycidyl ether (a1) of the dihydroxy compound having an alkylene chain or a polyether chain with the aromatic hydroxy compound (a2) is preferably carried out in the presence of a catalyst. Various catalysts can be used, and examples thereof include alkali (earth) metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate; phosphorus compounds such as triphenylphosphine; chlorides, bromides, and iodides such as 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30), 4-dimethylaminopyridine (DMAP), tetramethylammonium, tetraethylammonium, tetrabutylammonium, and benzyltributylammonium; quaternary ammonium salts such as chlorides, bromides, and iodides such as tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, and benzyltributylphosphonium; tertiary amines such as triethylamine, N,N-dimethylbenzylamine (DMBA), 1,8-diazabicyclo[5.4.0]undecene, and 1,4-diazabicyclo[2.2.2]octane; and imidazoles such as 2-ethyl-4-methylimidazole and 2-phenylimidazole. These catalysts may be used alone or in combination of two or more. Among them, sodium hydroxide, potassium hydroxide, triphenylphosphine, and DMP-30 are preferred because they allow the reaction to proceed quickly and are effective in reducing the amount of impurities by-products. The amount of these catalysts used is not particularly limited, but it is preferable to use 0.0001 to 0.1 moles per mole of phenolic hydroxyl groups in the aromatic hydroxy compound (a2). The form of the catalyst is also not particularly limited, and it may be used in the form of an aqueous solution or in the form of a solid.

[0127] "Solvent used in the reaction of (a1) and (a2)" The reaction between the diglycidyl ether (a1) of the dihydroxy compound having an alkylene chain or a polyether chain and the aromatic hydroxy compound (a2) can be carried out in the absence of a solvent or in the presence of an organic solvent. Examples of the organic solvent that can be used include alcohol solvents, glycol solvents, hydrocarbon solvents, ester solvents, ketone solvents, ether solvents, and dimethyl sulfoxide. Examples of the alcohol solvent include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, isobutanol, octanol, n-propyl alcohol, and acetylacetone alcohol. Examples of glycol-based solvents include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monomethyl ether acetate. Examples of ester-based solvents include methyl acetate, ethyl acetate, propyl acetate, and butyl acetate. Examples of ketone-based solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, and acetylacetone. Examples of ketone-based solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, and acetylacetone. Examples of ether-based solvents include ethyl ether, butyl ether, methyl cellosolve, ethyl cellosolve, dioxane, furan, and tetrahydrofuran.

[0128] The amount of the organic solvent used is usually preferably 50 to 300% by mass, more preferably 100 to 250% by mass, based on the total mass of the raw materials charged. The organic solvent may be used alone or in combination of two or more. In order to carry out the reaction quickly, no solvent is preferred, while the use of dimethyl sulfoxide is preferred in terms of reducing impurities in the final product.

[0129] "Conditions for the reaction of (a1) and (a2)" The reaction temperature when reacting (a1) with (a2) is typically 50 to 180°C, and the reaction time is typically 1 to 30 hours. From the viewpoint of reducing impurities in the final product, the reaction temperature is preferably 100 to 160°C. Furthermore, if the resulting compound exhibits significant coloration, an antioxidant or a reducing agent may be added to suppress this. The antioxidant is not particularly limited, but examples thereof include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite ester compounds containing a trivalent phosphorus atom. The reducing agent is not particularly limited, but examples thereof include hypophosphorous acid, phosphorous acid, thiosulfuric acid, sulfurous acid, hydrosulfite, and salts thereof.

[0130] After the reaction between (a1) and (a2) is completed, the reaction mixture may be neutralized or washed with water until the pH reaches 3 to 7, preferably 5 to 7. The neutralization and washing may be carried out in a conventional manner. For example, when a basic catalyst is used, an acidic substance such as hydrochloric acid, sodium dihydrogen phosphate, p-toluenesulfonic acid, or oxalic acid may be used as a neutralizing agent. After the neutralization or washing, the solvent is distilled off under reduced pressure and heating, if necessary, and the product is concentrated to obtain a hydroxy compound.

[0131] By using the glycidyl ether having an alkylene chain and the glycidyl ether having a polyether chain in combination, a hydroxy compound having both the structural unit X and the structural unit Y can be obtained. For example, a compound represented by the following structural formula is preferred.

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144] In each of the structural formulas above, ran represents a random bond, R' represents a divalent hydrocarbon group having 2 to 12 carbon atoms, n11 represents an integer from 4 to 16, n12 represents the average value of the repeating units and is 2 to 30, and m11 and m12 represent the average value of the repeating units and are each independently 0.5 to 25. However, each repeating unit present in the repeating unit may be the same or different.

[0145] Furthermore, by using the glycidyl ether having an alkylene chain as a raw material, a hydroxy compound having the structural unit X can be obtained, and for example, a compound represented by the following structural formula is preferred.

[0146]

[0147]

[0148]

[0149]

[0150]

[0151]

[0152]

[0153]

[0154]

[0155]

[0156]

[0157]

[0158] In each of the structural formulas above, n11 is an integer of 4 to 16, and m11 is the average value of the repeating units, which is 0.5 to 25.

[0159] Furthermore, by using the glycidyl ether having the polyether chain as a raw material, a hydroxy compound having the structural unit Y can be obtained, and for example, a compound represented by the following structural formula is preferred.

[0160]

[0161]

[0162]

[0163]

[0164]

[0165]

[0166]

[0167]

[0168]

[0169]

[0170]

[0171]

[0172] In each of the structural formulas above, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms, n12 is the average number of repeating units that is 2 to 30, and m12 is the average number of repeating units that is 0.5 to 25. However, each repeating unit present in the repeating unit may be the same or different.

[0173] In the method for producing the epoxy resin (A), the method for the glycidyl etherification reaction of the precursor (intermediate) hydroxy compound (a12) obtained above is not particularly limited, and examples thereof include a method of reacting a phenolic hydroxyl group with an epihalohydrin (a3), a method of olefinating the phenolic hydroxyl group and oxidizing the carbon-carbon double bond of the olefin with an oxidizing agent, etc. Among these, the method using epihalohydrin (a3) ​​is preferred in terms of ease of obtaining raw materials and ease of reaction.

[0174] Examples of the method using epihalohydrin (a3) ​​include a method in which 0.3 to 100 moles of epihalohydrin (a3) ​​are added per mole of phenolic hydroxyl groups in the hydroxy compound (a12) obtained above, and the mixture is reacted at a temperature of 20 to 120°C for 0.5 to 10 hours while adding, all at once or gradually, 0.9 to 2 moles of a basic catalyst per mole of phenolic hydroxyl groups in the hydroxy compound. The more excess the amount of epihalohydrin (a3) ​​added relative to the phenolic hydroxyl groups, the closer the resulting epoxy resin will be to a theoretical structure, and the more effectively it is possible to suppress the formation of secondary hydroxyl groups resulting from the reaction of unreacted phenolic hydroxyl groups with epoxy groups. From this perspective, it is preferable that the equivalent of epihalohydrin (a3) ​​added relative to the phenolic hydroxyl groups of the hydroxy compound is within the range of 2.5 to 100 equivalents. This basic catalyst may be in the form of a solid or an aqueous solution thereof. When an aqueous solution is used, it may be continuously added, and at the same time, water and epihalohydrin (a3) ​​may be continuously distilled from the reaction mixture under reduced pressure or under normal pressure, followed by liquid separation to remove water, and then the epihalohydrin (a3) ​​may be continuously returned to the reaction mixture.

[0175] In industrial production, all of the epihalohydrin (a3) ​​is freshly used in the first batch of epoxy resin production, but from the next batch onwards, it is preferred to use a combination of epihalohydrin (a3) ​​recovered from the crude reaction product and fresh epihalohydrin (a3) ​​equivalent to the amount consumed and lost in the reaction. The epihalohydrin (a3) ​​used in this case is not particularly limited, and examples include epichlorohydrin and epibromohydrin. Among these, epichlorohydrin is preferred because of its easy availability.

[0176] "Catalyst used in the reaction of precursor (a12) and (a3)" In the production method for the epoxy resin (A), examples of the catalyst used in the reaction of the precursor (intermediate) hydroxy compound (a12) obtained above with the (a3) ​​include the catalysts described above in the section "Catalyst used in the reaction of (a1) and (a2)".

[0177] "Solvent used in the reaction of precursor (a12) with (a3)" In the method for producing the epoxy resin (A), the reaction of the precursor (intermediate) hydroxy compound (a12) obtained above with the (a3) ​​can be carried out in the absence of a solvent or in the presence of an organic solvent. Examples of the organic solvent to be used include the solvents described above in "Solvent used in the reaction of (a1) with (a2)".

[0178] The reaction product of the precursor (a12) and the epihalohydrin (a3) ​​is washed with water, and then the unreacted epihalohydrin (a3) ​​and the organic solvent are removed by distillation under heating and reduced pressure. Furthermore, in order to reduce the hydrolyzable halogen content of the epoxy resin (A), the resulting epoxy resin can be dissolved again in an organic solvent such as toluene, methyl isobutyl ketone, or methyl ethyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide can be added to further carry out the reaction. In this case, a phase transfer catalyst such as a quaternary ammonium salt or a crown ether may be present in order to improve the reaction rate.

[0179] When the phase transfer catalyst is used, the amount thereof is preferably in the range of 0.1 to 3 mass % based on the solid content of the reaction product. After completion of the reaction, the salt formed is removed by filtration, washing with water, etc., and the solvent such as toluene or methyl isobutyl ketone is further distilled off under heating and reduced pressure to obtain a high-purity epoxy resin.

[0180] [Epoxy resin (B)]

[0181] The epoxy resin (B) may have any structure as long as its epoxy equivalent is within the range of 100 to 300 g / equivalent. Examples thereof include liquid epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD ​​type epoxy resins, polyhydroxybenzene type epoxy resins, polyhydroxynaphthalene type epoxy resins, biphenyl type epoxy resins, and tetramethylbiphenyl type epoxy resins; brominated epoxy resins such as brominated phenol novolac type epoxy resins; solid bisphenol A type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, triphenylmethane type epoxy resins, and tetraphenyl Examples of epoxy resins include benzene-type epoxy resins, dicyclopentadiene-phenol addition reaction type epoxy resins, phenol aralkyl-type epoxy resins, phenylene ether-type epoxy resins, naphthylene ether-type epoxy resins, naphthol novolac-type epoxy resins, naphthol aralkyl-type epoxy resins, naphthol-phenol co-condensed novolac-type epoxy resins, naphthol-cresol co-condensed novolac-type epoxy resins, and biphenyl-modified novolac-type epoxy resins. These may be used alone or in combination of two or more, and it is preferable to select and use various types depending on the intended use, the physical properties of the cured product, etc.

[0182] Among these, it is preferable to use liquid epoxy resins such as bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bisphenol AD ​​epoxy resins, polyhydroxybenzene epoxy resins, polyhydroxynaphthalene epoxy resins, biphenyl epoxy resins, and tetramethylbiphenyl epoxy resins, which have an epoxy equivalent of 100 to 300 g / equivalent. It is particularly preferable to use bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, and bisphenol AD ​​epoxy resins, which have an epoxy equivalent of 100 to 300 g / equivalent. The epoxy equivalent is preferably 120 to 250, more preferably 130 to 230, and even more preferably 150 to 210.

[0183] In order to provide an epoxy resin cured product with excellent adhesiveness, flexibility, and dismantlability, the viscosity of the epoxy resin (B) at 25°C is preferably 500 mPa·s to 30,000 mPa·s, more preferably 700 mPa·s to 25,000 mPa·s, and even more preferably 1,000 mPa·s to 20,000 mPa·s. The total chlorine content is preferably 0.001 to 20 mass%, more preferably 0.001 to 15 mass%, even more preferably 0.01 to 10 mass%, and even more preferably 0.01 to 5 mass%.

[0184] In the present embodiment, the ratio of the epoxy resin (A) to the epoxy resin (B) used is not particularly limited, but from the viewpoint that a phase-separated structure is likely to occur in the cured product when the epoxy resin composition is cured, the mass ratio (A):(B) of the epoxy resin (A) to the epoxy resin (B) is 90:10 to 10:90, preferably 80:20 to 20:80, more preferably 70:30 to 30:70, and particularly preferably 60:40 to 40:60. By phase separation in the cured product and forming a sea-island structure, the cured product achieves both good adhesiveness and stress relaxation ability, exhibits high adhesive strength particularly over a wide temperature range, and has the effect of reducing the molding shrinkage rate before and after heat curing of the resin composition.

[0185] The phase-separated structure is formed spontaneously during the curing reaction based on the compatibility between the epoxy resin (A) and the epoxy resin (B). It generally consists of island phases of resin particles with an average particle size of 10 nm to 100 μm and a surrounding matrix (sea phase). The cured products of the resin particles and the matrix are determined by their blending ratios, the type of curing agent, and the effect of the curing agent. In other words, either the resin particles contain a cured product of the epoxy resin (A) and the matrix contains a cured product of the epoxy resin (B), or the resin particles contain a cured product of the epoxy resin (B) and the matrix contains a cured product of the epoxy resin (A), are possible.

[0186] The phase-separated structure of the cured product can be observed using a microscope such as a scanning electron microscope (SEM) or an atomic force microscope (AFM). When a sea-island structure is formed, the particle size of the island phases can be measured. In the present invention, the average particle size of the resin particles is determined by randomly selecting 50 island phases from the island phases within a 200 μm × 260 μm field of view, measuring the particle sizes of the selected 50 island phases, and calculating the average. Furthermore, the relative hardness distribution of the sea phase and the island phases can be confirmed by AFM observation.

[0187] [Heterocyclic aromatic compound (C) having a tertiary amino group] The heterocyclic aromatic compound (C) having a tertiary amino group (hereinafter sometimes simply referred to as "compound (C)"), which is optionally contained in the epoxy resin composition according to this embodiment, is not particularly limited, and it is sufficient that it has a tertiary amino group and an aromatic heterocycle (aromatic heterocycle) in the molecule. When the aromatic heterocycle itself has a tertiary amino group, it is sufficient that only the aromatic heterocycle is present. The heterocyclic aromatic compound (C) having a tertiary amino group can also be referred to as an aromatic heterocyclic compound (C) having a tertiary amino group.

[0188] Examples of the compound (C) include imidazole compounds, imidazoline compounds, and pyridine compounds having a tertiary amino group.

[0189] The imidazole compound may be a substituted or unsubstituted imidazole. Specific examples of the imidazole compound include imidazole (SIZ), 1-methylimidazole (1-MZ), 2-methylimidazole, 4-methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 4-ethylimidazole, 1-n-propylimidazole, 2-n-propylimidazole, 1-isopropylimidazole, 2-isopropylimidazole, and 1-n-butylimidazole. 2-n-butylimidazole, 1-isobutylimidazole, 2-isobutylimidazole, 2-undecyl-1H-imidazole, 2-heptadecyl-1H-imidazole, 1,2-dimethylimidazole, 1,3-dimethylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole (2E4MZ), 1-phenylimidazole, 2-phenyl-1H-imidazole, 4-methyl- Examples of the alkyl acrylate include 2-phenyl-1H-imidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-phenyl-4,5-di(2-cyanoethoxy)methylimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, and 1-benzyl-2-phenylimidazole hydrochloride. Among these, imidazole (SIZ), 1-methylimidazole (1-MZ), or 2-ethyl-4-methylimidazole (2E4MZ) is preferred.

[0190] The imidazoline compounds include substituted or unsubstituted imidazolines, and specific examples of the imidazole compounds include 2-methylimidazoline, 2-ethylimidazoline, 2-phenylimidazoline, and 2-benzylimidazoline.

[0191] Examples of the pyridine compound having a tertiary amino group include substituted or unsubstituted pyridines having a tertiary amino group. Specific examples of the pyridine compound having a tertiary amino group include dialkylaminopyridines (DAAP) such as 2-dimethylaminopyridine, 3-dimethylaminopyridine, 4-dimethylaminopyridine (DMAP), 2-diethylaminopyridine, 3-diethylaminopyridine, and 4-diethylaminopyridine (DEAP), pyrrolidinopyridine, piperazinylpyridine, and morpholinopyridine. Among these, dialkylaminopyridine (DAAP) is preferred, and 4-dimethylaminopyridine (DMAP) is more preferred. These compounds may be used alone or in combination of two or more.

[0192] The compound (C) is preferably used in an amount within a range of 2 to 20 parts by mass, more preferably 3 to 15 parts by mass, and even more preferably 5 to 12 parts by mass, relative to 100 parts by mass of the total of the epoxy resin (A) and the epoxy resin (B), from the viewpoint of exhibiting the effect of sufficiently expanding and reducing adhesiveness when dismantled after use, without impairing the adhesiveness after curing or the flexibility of the cured product when the epoxy resin composition according to this embodiment is used as an adhesive.

[0193] The compound (C) is usually used as a curing accelerator in combination with a curing agent in curing an epoxy resin, but in the epoxy resin composition according to this embodiment, the compound (C) may be used as a curing agent for the epoxy resin.

[0194] [Thermal-Expandable Particles (D)] The thermally-expandable particles (D) optionally contained in the epoxy resin composition according to this embodiment may be made of an inorganic material or an organic material. Examples of such materials include the expandable graphite disclosed in JP-A-2000-44219. Examples of those made of organic materials include thermally-expandable microcapsules in which a thermoplastic polymer is used as an outer shell and a volatile expanding agent that becomes gaseous at a temperature below the softening point of the thermoplastic polymer is microencapsulated.

[0195] Among these, it is preferable to use thermally expandable microcapsules made of the organic material, since they have uniform dispersibility when made into an epoxy resin composition and excellent electrical insulation properties as the resulting epoxy resin cured product.

[0196] Among these, it is preferable to use the expandable graphite because the expandable particles have excellent heat resistance and durability, the resulting epoxy resin cured product has excellent electrical conductivity, and the expandable particles themselves can generate heat by induction heating or microwaves.

[0197] "Thermally Expandable Microcapsules" A method for producing the thermally expandable microcapsules has been disclosed in Japanese Patent Publication No. 42-26524. However, from the viewpoint of thermally curing the epoxy resin in this embodiment, it is preferable that the microcapsules have heat resistance. Methods for producing the heat-resistant thermally expandable microcapsules are disclosed in, for example, WO99 / 46320, WO99 / 43758, and Japanese Patent Laid-Open No. 2002-226620.

[0198] That is, it is preferable that the particles do not expand thermally during the thermal curing of the epoxy resin, but maintain their shape as particles, and then expand after use due to higher temperature thermal energy. For example, it is preferable that the thermally expandable microcapsules have a shell polymer formed by polymerizing a nitrile monomer and a monomer having a carboxyl group as essential components.

[0199] In order to further impart heat resistance, it is also preferable to use a monomer having an amide group or a monomer having a cyclic structure in the side chain in combination.

[0200] In the method for producing the heat-resistant thermally expandable microcapsules, for example, the shell polymer is prepared by appropriately blending a thermal polymerization initiator with the above-mentioned components. Known thermal polymerization initiators, such as peroxides and azo compounds, can be used as the thermal polymerization initiator. Examples of the thermal polymerization initiator include azobisisobutyronitrile (AIBN), benzoyl peroxide, lauryl peroxide, diisopropyl peroxydicarbonate, t-butyl peroxide, and 2,2'-azobis(2,4-dimethylvaleronitrile). Preferably, a thermal polymerization initiator that is soluble in the polymerizable monomer used is used. The glass transition temperature (Tg) of the polymer constituting the shell of the thermally expandable microcapsules is desirably 120°C or higher. The Tg of the polymer can be calculated from the Tg of each homopolymer of the constituent monomers. The Tg of the polymer can also be measured by differential scanning calorimetry (DSC) or the like.

[0201] The volatile expanding agent contained in the microcapsules is a substance that becomes gaseous below the softening point of the shell polymer, and known substances are used. Examples include propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, nonane, decane, petroleum ether, methane, and their respective halides, low-boiling liquids such as tetraalkylsilane, or compounds such as azobisisobutyronitrile (AIBN) that thermally decompose into gas upon heating. The volatile expanding agent is selected as needed depending on the temperature range in which the capsules are to be expanded. The volatile expanding agent can be used alone or in combination of two or more types.

[0202] Other examples include fluorine-based compounds such as hydrochlorofluorocarbons, hydrofluorocarbons, and hydrofluoroethers; commonly known as chlorofluorocarbons, fluorocarbons, and fluoroethers; however, their use is best avoided in the current social climate due to concerns about ozone layer depletion and global warming. For actual production, conventional methods for producing thermally expandable microcapsules are used. In other words, inorganic fine particles such as silica, magnesium hydroxide, calcium phosphate, and aluminum hydroxide are used as dispersion stabilizers in aqueous systems. Other examples of dispersion stabilization aids include condensation products of diethanolamine and aliphatic dicarboxylic acids, polyvinylpyrrolidone, methylcellulose, polyethylene oxide, polyvinyl alcohol, and various emulsifiers.

[0203] The average particle size of the thermally expandable microcapsules is preferably 1 to 500 μm, more preferably 3 to 100 μm, and even more preferably 5 to 50 μm. The average particle size of the thermally expandable microcapsules can be measured, for example, by measuring the volume average particle size using a particle size distribution diameter measuring instrument (LA-950, manufactured by HORIBA).

[0204] "Expanded Graphite" A method for producing the expanded graphite is disclosed in, for example, JP 2000-44219 A, etc., but from the viewpoint of thermally curing the epoxy resin in this embodiment, it is preferable that the expanded graphite has heat resistance. A method for producing the heat-resistant expanded graphite is disclosed in, for example, JP 2012-193053 A, etc.

[0205] The expanded graphite can usually be obtained by treating graphite, such as natural graphite, pyrolytic graphite, or kish graphite, with a mixture of concentrated sulfuric acid and a strong oxidizing agent (hereinafter referred to as acid treatment) to form an intercalation compound between the graphite layers, followed by washing with water, filtration, and drying. The acid treatment method typically uses a concentrated sulfuric acid-based mixture, such as concentrated sulfuric acid and nitric acid, concentrated sulfuric acid and potassium permanganate, concentrated sulfuric acid and perchloric acid, or concentrated sulfuric acid and hydrogen peroxide. Methods using only fuming nitric acid are also known. A neutralization step with a base may be performed after the acid treatment. The pH of the water from which the expanded graphite is extracted is preferably 5 to 9, more preferably 6 to 8. Furthermore, the pH of the water extracted when the expanded graphite is heated in water is preferably 4 to 8, more preferably 5 to 8, and even more preferably 6 to 8.

[0206] The expanded graphite is selected based on the range of the major axis of the particles. For this reason, commercially available expanded graphite is expressed in terms of particle size instead of major axis. Specifically, commercially available expanded graphite is classified using a sieve, and the characteristics of the expanded graphite product are expressed based on the mesh size and the particle size of the sieve.

[0207] The particle size of the expanded graphite is preferably 20 to 300 mesh, more preferably 30 to 200 mesh.

[0208] The thermally expandable particles (D) may be mixed directly with the epoxy resin (A) and the epoxy resin (B), or may be mixed with the epoxy resin (A) and the epoxy resin (B) using a master batch in which the thermally expandable particles (D) are dispersed at a high concentration in various resins.

[0209] The thermally expandable particles (D) may be commercially available. Examples of commercially available products include expansion capsules manufactured by Nippon Phillite Co., Ltd. (trade name: Expancel (registered trademark)), expansion capsules manufactured by Sekisui Chemical Co., Ltd. (trade name: Advancel EM), microspheres manufactured by Matsumoto Yushi Seiyaku Co., Ltd. (trade names: F-20D, F-30D, F-40D, FN-100D, FN-100MD, FN-100SD, FN-100SSD, FN-180D, FN-180SD, FN-180SSD, F-190D, F-260D), and microspheres manufactured by Kureha Corporation (trade names: H850D, H880D, S2340D, S2 640D), expanded graphite manufactured by Fuji Graphite Industries Co., Ltd. (trade names: EXP-50S120K, EXP-50S150), expanded graphite manufactured by Ito Graphite Industries Co., Ltd. (trade names: 953240L, 9550250), expanded graphite manufactured by Air Water Inc. (trade names: 50LTE-U, MZ-260, CA-60, SS-3, SS-3LA), and expanded graphite manufactured by Graphtec International (trade name: GRAFGUARD (registered trademark)). It is preferable to appropriately select particles that do not thermally expand at the curing temperature of the epoxy resin composition but thermally expand at the heating temperature during dismantling.

[0210] The proportion of the thermally expandable particles (D) used is preferably within a range of 3 to 40 parts by mass, more preferably 5 to 30 parts by mass, even more preferably 6 to 20 parts by mass, and particularly preferably 7 to 15 parts by mass, relative to 100 parts by mass of the total of the epoxy resin (A) and the epoxy resin (B), from the viewpoint of exhibiting the effect of sufficiently expanding and reducing adhesiveness when dismantled after use without impairing the adhesiveness after curing or the flexibility of the cured product when the epoxy resin composition according to this embodiment is used as an adhesive.

[0211] [Glycidyl Ether Group-Containing Compound (E)] The glycidyl ether group-containing compound (E) is a glycidyl ether group-containing compound formed by connecting a structural unit V having one or more glycidyl ether groups and a structural unit W different from the structural unit V via the V-W-V bond, in which the structural unit W and the structural unit V are bonded via a reversible bond, and preferably formed by a reversible bond formed by a Diels-Alder reaction between a furan structure and a maleimide structure.

[0212] The glycidyl ether group-containing compound (E) is incorporated into a crosslinked structure through a curing reaction based on the glycidyl ether group. On the other hand, since it retains reversibility even after being cured, it has high molecular mobility even in the cured product. Therefore, when the cured product is exposed to high temperatures or subjected to impact, cracking, or crushing, the reversible bond is broken, resulting in dismantling properties. On the other hand, the reversible bond reversibly reforms at low temperatures, including room temperature, resulting in excellent adhesive properties.

[0213] To introduce a furan-type addition structure (reversible bond) into a compound by the Diels-Alder reaction, a furan having a glycidyl group on the furan ring or a maleimide having a glycidyl group is used. A specific partial structure of the reversible bond can be represented by the following chemical formula. A reversible bond can be introduced into a compound by bonding the R moiety in the following formula derived from maleimide or various glycidyl groups on the ring derived from furan with other structural units.

[0214]

[0215] In the Diels-Alder reaction, a conjugated diene and a parent diene undergo an addition reaction to form a six-membered ring. Because the Diels-Alder reaction is an equilibrium reaction, a retro-Diels-Alder reaction occurs at a predetermined temperature, resulting in dissociation (decrosslinking). When mechanical energy, such as a scratch or external force, is applied to the resulting cured product, the C-C bond of the Diels-Alder reaction unit is preferentially cleaved because the C-C bond has lower bond energy than a normal covalent bond. This allows the cured product to exhibit dismantling properties. Furthermore, in a temperature range lower than the dissociation temperature, the equilibrium of the C-C bond of the Diels-Alder reaction unit shifts toward the bond, thereby again forming an adduct (Diels-Alder reaction unit).

[0216] In the reversible bond formed by the Diels-Alder reaction, the reversible bond formed by the Diels-Alder reaction with the furan structure and the maleimide structure undergoes a Retro-Diels-Alder reaction and dissociates (decrosslinks) at around 120° C. Therefore, the heating temperature required for the cured product to exhibit easy dismantling properties can be reduced, and the product has excellent dismantling properties for applications where high-temperature heating is not suitable.

[0217] The above-mentioned reversible bond is present at at least two locations in the target glycidyl ether group-containing compound (E), but from the viewpoint of achieving excellent adhesion, flexibility, and dismantling properties of the cured product, it is preferable that the structural unit W also has a plurality of the above-mentioned reversible bonds.

[0218] For the same reasons as above, the molecular weight of the structural unit W is preferably at least a certain size, and for example, its average molecular weight (Mw) is preferably at least 28. When the structural unit W contains a reversible bond, the molecular weight between the reversible bonds is preferably at least 28. Note that the structural unit W may contain a crosslinkable functional group similar to the glycidyl ether group in the structural unit V, but from the viewpoint of more easily achieving the effects of the present invention, it is preferable that the structural unit W does not contain a crosslinkable (curable) functional group.

[0219] The structural unit W may contain an alkylene chain or an alkylene ether chain from the viewpoint of achieving excellent adhesion, flexibility, and dismantling properties of the cured product when the glycidyl ether group-containing compound (E) of the present invention is used, for example, as a structural adhesive. In this case, the alkylene chain more preferably has 2 to 30 carbon atoms, and most preferably has 4 to 16 carbon atoms. The alkylene ether chain is not particularly limited, but is preferably an alkylene ether chain having 2 to 12 carbon atoms, and the average number of repetitions thereof is preferably in the range of 2 to 30.

[0220] The number of glycidyl ether groups in the structural unit V is not particularly limited, but from the viewpoint of industrial availability of raw materials and excellent adhesion, flexibility, and dismantling properties of a cured product, it is preferably in the range of 1 to 3, and more preferably 1 to 2.

[0221] The average molecular weight (Mw) of the glycidyl ether group-containing compound (E) is not particularly limited, but is preferably less than 1,000 from the viewpoints of adhesive strength, dismantling property, and flexibility of the resulting cured product.

[0222] The epoxy equivalent of the glycidyl ether group-containing compound (E) is preferably 150 to 1000 g / equivalent, more preferably 180 to 800 g / equivalent, and even more preferably 200 to 700 g / equivalent.

[0223] The glycidyl ether group-containing compound (E) is preferably a compound represented by the following general formula (4):

[0224] [In formula (4), m ３ is an integer from 1 to 4. １ is the following formula (5), Z ３is any of the structures represented by the following formula (6), and a plurality of such structures in one molecule may be the same or different. Furthermore, any of the maleimide structures at both ends of formula (4) may or may not have a substituent. When the maleimide has a substituent, preferred examples of the substituent include an alkyl group, a halogen atom, a glycidyl ether group, and a 2-methylglycidyl ether group.

[0225] [In formula (5), the aromatic ring may be unsubstituted or may have a substituent, * represents a bonding point, and G represents a glycidyl group or a 2-methylglycidyl group.]

[0226] (In formula (6), each R″ is independently a hydrogen atom, a methyl group, or an ethyl group; w1 is an integer of 1 to 30; w2 is the average number of repeats and is 0.5 to 8; w3 is the average number of repeats and is 0.5 to 6; and * represents a bonding point.)

[0227] Among these, from the viewpoints of the availability of raw materials and the mechanical properties of the resulting cured product, it is preferable that w1 is within the range of 1 to 15, w2 is within the range of 0.5 to 3, w3 is preferably an integer of 1 to 4, and R″ is preferably a hydrogen atom.

[0228] The general formula (4) has a reversible bond formed by furan and maleimide at its terminal. The terminal furan structure in the general formula (4) has Z1, which is any of the structures represented by the general formula (5), and this glycidyl ether group or 2-methylglycidyl ether group contributes to the curing reaction in the epoxy resin composition described below.

[0229] Z in the formula １ is a structural unit having a glycidyl ether group or a 2-methylglycidyl ether group, represented by the general formula (5) above, but among these, from the viewpoints of availability of raw materials and reactivity of the glycidyl group during curing of the epoxy resin composition, those of the following structural formula are preferred: G is a glycidyl group or a 2-methylglycidyl group.

[0230]

[0231] Examples of the glycidyl ether group-containing compound (E) include, but are not limited to, those shown below.

[0232]

[0233] <Method for producing glycidyl ether group-containing compound (E)> The method for producing the glycidyl ether group-containing compound (E) is not particularly limited, and the compound can be produced stepwise using known reactions depending on the target structure, or by appropriately combining commercially available raw materials. Representative production methods will be described later.

[0234] The compound represented by the general formula (4) has two Diels-Alder reaction units each consisting of a furan structure and a maleimide structure as a reversible bond in the molecule, and in the general formula (4), Z １ This can be obtained by using a furan compound having the structure:

[0235] It is known that the Diels-Alder reaction in which a conjugated diene such as the furan structure and a parent diene such as the maleimide structure undergo an addition reaction to form a six-membered ring is an equilibrium reaction, and that at a temperature higher than the temperature at which the addition reaction proceeds, the addition reaction moiety dissociates to return to the original conjugated diene and parent diene, thereby causing a retro-Diels-Alder reaction, which is a reverse reaction.

[0236] The Diels-Alder reaction may be carried out by a known method. For example, a conjugated diene compound and a parent diene compound are mixed in equimolar amounts, or optionally one of the components may be in excess, and the mixture is melted by heating or dissolved in a solvent, followed by stirring at room temperature to 110°C for 1 to 24 hours to obtain a reaction product. The reaction product can be obtained by filtration or solvent distillation without purification, or by a commonly used isolation and purification method such as recrystallization, reprecipitation, or chromatography.

[0237] The above-mentioned "equimolar amounts of the conjugated diene compound and the parent diene compound" means that the conjugated diene structure of the conjugated diene compound and the ethylene structure of the parent diene compound are equimolar. For example, in the case of the glycidyl ether group-containing compound (E) represented by the above-mentioned general formula (4), when the furan compound as the conjugated diene compound has one conjugated diene structure per molecule and the maleimide compound (bismaleimide) as the parent diene compound has two maleimide structures (ethylene structures) per molecule, the above-mentioned "equimolar amounts of the conjugated diene compound and the parent diene compound" means that the molar ratio of the furan compound to the maleimide compound (bismaleimide) is 2:1.

[0238] <Z １ Furan compounds having the structure Z １ (Z in the general formula (4) １ The furan compound having a hydroxyl group can be obtained by reacting a furan compound having a hydroxyl group with epihalohydrin (a3) ​​and converting the hydroxyl group in the furan compound into a glycidyl ether group. Examples of the furan compound having a hydroxyl group include any of the compounds listed in the following formulas. The hydroxyl group in these compounds can be converted into a glycidyl ether group by known methods, for example, as described in the examples.

[0239]

[0240] Among the compounds of the above formula, the compounds shown below are particularly preferred in terms of their reactivity and the excellent adhesiveness, flexibility and dismantling properties of the resulting cured product.

[0241]

[0242] The structures of the above furan compounds include those having, independently of one another, a hydrogen atom, a halogen atom, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amido group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group as a substituent. Furthermore, in the structures of the compounds listed in the above formula, the alkoxy group, the aralkyloxy group, the aryloxy group, the carboxy group, the alkyloxycarbonyl group, the aryloxycarbonyl group, the alkyl group, the cycloalkyl group, the aralkyl group, and the aryl group also include those having various substituents further bonded to their carbon atoms.

[0243] The obtained Z １ The epoxy equivalent of the furan compound having the structure shown above is preferably 100 to 500 g / equivalent, more preferably 110 to 400 g / equivalent, and even more preferably 120 to 300 g / equivalent.

[0244] The obtained Z １ The viscosity of the furan compound having the structure shown above at 25° C. is preferably 0.1 to 50,000 mPa·s, more preferably 0.5 to 30,000 mPa·s, and even more preferably 1 to 20,000 mPa·s.

[0245] <Z ３ Maleimide compound (bismaleimide) having the structure ３ (Z in the general formula (4) ３ The maleimide compound (bismaleimide) having the formula (I) is an intermediate of the parent diene before the Diels-Alder reaction, and can be represented by, for example, the following general formula (1)'.

[0246] [In the ceremony, Z ３ represents Z in the general formula (4). ３ is the same as

[0247] The maleimide compound is preferably one having the following structure from the viewpoints of ease of raw material availability, solvent solubility during the Diels-Alder reaction, and adhesive strength when the compound obtained by the Diels-Alder reaction is cured.

[0248]

[0249] Said Z ３ The maleimide compound (bismaleimide) having the structure shown above may be a commercially available product or may be synthesized.

[0250] Commercially available maleimide compounds include, for example, maleimide compounds manufactured by Daiwa Kasei Co., Ltd. (trade names: BMI-1000, BMI-1000H, BMI-1100, BMI-1100H, BMI-3000, BMI-3000H, BMI-4000, BMI-5100, BMI-7000, BMI-7000H, BMI-TMH), maleimide compounds manufactured by K.I. Kasei Co., Ltd. (trade names: BMI, BMI-70, BMI-80), maleimide compounds manufactured by JFE Chemical Co., Ltd. (trade names: JBM-200N, JBM-300N, JBM-800N), and DESIGNER Examples of such maleimide compounds include those manufactured by MOLECULES (trade names: BMI-689, BMI-1400, BMI-1500, BMI-1700, BMI-3000, BMI-5000, etc.).

[0251] Examples of the method for synthesizing the maleimide compound include the following first and second methods. ３ The maleimide compound can be synthesized by reacting a diamine compound having the structure and two amino groups with maleic anhydrides. As the second method, for example, the maleimide compound (MI-ts-N-st-MI) can be synthesized by reacting a compound having two functional groups S (S-N-S) with a maleimide compound (T-MI) having a functional group T that can react with the functional group S. MI corresponds to the terminal maleimide structure, and "-ts-N-st-" corresponds to the Z ３ "ts" corresponds to the structure obtained by reaction of the substituent T with the substituent S.

[0252] "First Method" In the first method, for example, a compound of the formula: NH ２ -Z ３ -NH ２ The maleic anhydride can be synthesized by a known method using the diamine compound represented by the formula (I) and a maleic anhydride. For example, the diamine compound is reacted with the maleic anhydride in a solvent in the presence of an acid catalyst to form maleamic acid, which is then maleimidized (ring-closed by dehydration) using an acid catalyst or the like to obtain a crude maleimide compound solution, which is then purified. Examples of the maleic anhydride include maleic anhydride, citraconic anhydride, and 2,3-dimethylmaleic anhydride. Among these, maleic anhydride is preferred.

[0253] "Second Method" The maleimide compound (bismaleimide) can be synthesized by using a compound having hydroxy groups at both ends as the compound having two functional groups S (S-N-S) and using glycidyloxyphenylmaleimide as the maleimide compound having the functional group T (T-MI). The hydroxy groups of the compound having hydroxy groups at both ends are reacted with the glycidyloxy groups of glycidyloxyphenylmaleimide, thereby introducing a maleimide structure into the ends.

[0254] The compound having hydroxy groups at both ends can be synthesized, for example, by the following method: A diglycidyl ether of an aliphatic dihydroxy compound or an aliphatic divinyl ether is reacted with an aromatic hydroxy compound to obtain a compound having hydroxy groups at its ends.

[0255] Alternatively, the maleimide compound (bismaleimide) can be synthesized by using a compound having glycidyl ether groups at both ends as the compound having two functional groups S (S-N-S) and using hydroxyphenylmaleimide as the maleimide compound having the functional group T (T-MI). For example, after obtaining the compound having hydroxy groups at both ends, this is epoxidized to convert the ends into glycidyl ether groups, and then the compound is reacted with hydroxyphenylmaleimide or the like to introduce a maleimide structure at the ends.

[0256] Alternatively, the maleimide compound (bismaleimide) can be synthesized by using a compound having halogenated alkyl groups at both ends as the compound having two functional groups S (S-N-S) and using hydroxyphenylmaleimide as the maleimide compound having the functional group T (T-MI). For example, an aromatic dihydroxy compound is reacted with a dihalogenated alkyl compound or a dihalogenated aralkyl compound to obtain a compound having halogenated alkyl groups at the ends, and then the compound is reacted with hydroxyphenylmaleimide or the like to introduce a maleimide structure at the ends.

[0257] The diglycidyl ether of the aliphatic dihydroxy compound is not particularly limited, and examples thereof include the same specific examples as those of the diglycidyl ether (a1) of the dihydroxy compound having an alkylene chain or a polyether chain.

[0258] Among these, compounds having a structure in which glycidyl groups are linked via ether groups to both ends of an alkylene chain having 12 to 14 carbon atoms are preferred, from the viewpoint of excellent adhesion, flexibility, and dismantlability of the resulting cured product, and it is most preferred to use 1,12-dodecanediol diglycidyl ether, 1,13-tridecanediol, or 1,14-tetradecanediol diglycidyl ether.

[0259] The aliphatic divinyl ether is not particularly limited, and examples thereof include divinyl ethers of linear alkylene groups such as polyethylene glycol divinyl ether, polypropylene glycol divinyl ether, polytetramethylene glycol divinyl ether, 1,3-butylene glycol divinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, 1,9-nonanediol divinyl ether, and 1,10-decanediol divinyl ether, and divinyl ethers of branched alkylene groups such as neopentyl glycol divinyl ether, divinyl ethers containing a cycloalkane structure such as 1,4-cyclohexanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, tricyclodecanediol divinyl ether, tricyclodecane dimethanol divinyl ether, pentacyclopentadecanedimethanol divinyl ether, and pentacyclopentadecanediol divinyl ether, bisphenol A divinyl ether, bisphenol F divinyl ether, and hydroquinone divinyl ether. These may be used alone or in combination of two or more.

[0260] Among these, divinyl ethers having a polyether structure or a linear alkylene chain having 4 to 10 carbon atoms are preferred from the viewpoint of excellent adhesion, flexibility, and dismantling properties of the resulting cured product, and it is most preferred to use polyethylene glycol divinyl ether, polypropylene glycol divinyl ether, polytetramethylene glycol divinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, 1,9-nonanediol divinyl ether, or 1,10-decanediol divinyl ether.

[0261] The aromatic hydroxy compound is not particularly limited, and examples thereof include the same specific examples as those of the aromatic hydroxy compound (a2).

[0262] Among these, bisphenols are preferred because they provide excellent adhesion, flexibility, and dismantling properties when cured, and bis(4-hydroxyphenyl)methane and 2,2-bis(4-hydroxyphenyl)propane are particularly preferred because they provide excellent toughness. Furthermore, when importance is placed on the moisture resistance of the cured product, it is preferable to use phenols containing an alicyclic structure.

[0263] The reaction ratio of the diglycidyl ether of the aliphatic dihydroxy compound to the aromatic hydroxy compound is preferably in the range of 1 / 1.01 to 1 / 5.0 (molar ratio) of the former / the latter, and from the viewpoint of providing a well-balanced combination of flexibility and heat resistance of the resulting cured product, it is preferable that (a1) / (a2) is 1 / 1.02 to 1 / 3.0 (molar ratio).

[0264] The reaction between the diglycidyl ether of the aliphatic dihydroxy compound and the aromatic hydroxy compound is preferably carried out in the presence of a catalyst, such as the catalysts described above in the section "Catalysts used in the reaction of (a1) and (a2)."

[0265] The reaction between the diglycidyl ether of the aliphatic dihydroxy compound and the aromatic hydroxy compound can be carried out in the absence of a solvent or in the presence of an organic solvent. Examples of organic solvents that can be used include those described above in the section "Solvents Used in the Reaction of (a1) and (a2)." The amount of organic solvent used is usually 50 to 300% by mass, preferably 100 to 250% by mass, based on the total mass of the raw materials charged. These organic solvents may be used alone or in combination of two or more. The use of no solvent is preferred to rapidly carry out the reaction, while the use of dimethyl sulfoxide is preferred to reduce impurities in the final product.

[0266] The reaction temperature when carrying out the reaction is typically 50 to 180°C, and the reaction time is typically 1 to 10 hours. A reaction temperature of 100 to 160°C is preferred from the viewpoint of reducing impurities in the final product. Furthermore, if the resulting compound exhibits significant coloration, an antioxidant or a reducing agent may be added to suppress this. The antioxidant is not particularly limited, but examples thereof include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite ester compounds containing a trivalent phosphorus atom. The reducing agent is not particularly limited, but examples thereof include hypophosphorous acid, phosphorous acid, thiosulfuric acid, sulfurous acid, hydrosulfite, and salts thereof.

[0267] After completion of the reaction, the reaction mixture can be neutralized or washed with water until the pH reaches 3 to 7, preferably 5 to 7. The neutralization and washing can be carried out according to a conventional method. For example, when a basic catalyst is used, an acidic substance such as hydrochloric acid, sodium hydrogen phosphate monobasic, p-toluenesulfonic acid, or oxalic acid can be used as a neutralizing agent. After neutralization or washing, the solvent can be distilled off under reduced pressure and heating, if necessary, and the product can be concentrated to obtain the compound.

[0268] The reaction ratio of the aliphatic divinyl ether to the aromatic hydroxy compound is preferably in the range of 1 / 1.01 to 1 / 5.0 (molar ratio) of the former / the latter, and from the viewpoint of providing a well-balanced cured product having flexibility and heat resistance, it is preferable that (a1) / (a2) is in the range of 1 / 1.02 to 1 / 3.0 (molar ratio).

[0269] The reaction between the diglycidyl ether of the aliphatic dihydroxy compound and the aromatic hydroxy compound proceeds sufficiently without a catalyst, but a catalyst can be used as appropriate to select the raw materials and increase the reaction rate. Examples of catalysts that can be used include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid; organic acids such as toluenesulfonic acid, methanesulfonic acid, xylenesulfonic acid, trifluoromethanesulfonic acid, oxalic acid, formic acid, trichloroacetic acid, and trifluoroacetic acid; and Lewis acids such as aluminum chloride, iron chloride, tin chloride, gallium chloride, titanium chloride, aluminum bromide, gallium bromide, boron trifluoride ether complex, and boron trifluoride phenol complex. The amount of catalyst used is usually within the range of 10 ppm to 1% by mass relative to the mass of the divinyl ether compound. In this case, it is preferable to select the type and amount of catalyst used so as not to cause a nuclear addition reaction of the vinyl group to the aromatic ring.

[0270] The reaction between the aliphatic divinyl ether and the aromatic hydroxy compound can be carried out in the absence of a solvent or in the presence of an organic solvent. Examples of the organic solvent include those described above in the section "Solvents Used in the Reaction of (a1) and (a2)." The amount of the organic solvent used is usually 50 to 300% by mass, preferably 100 to 250% by mass, based on the total mass of the raw materials charged. These organic solvents may be used alone or in combination of two or more.

[0271] The reaction temperature is usually 50 to 150° C., and the reaction time is usually 0.5 to 10 hours. In this case, the reaction is preferably carried out in an oxygen atmosphere to prevent self-polymerization of the vinyl ether group.

[0272] After the completion of the reaction, if an organic solvent was used, it is removed under reduced pressure and heating, and if a catalyst was used, it is deactivated with a deactivator or the like as necessary, and then removed by washing with water or filtration, thereby obtaining the compound.

[0273] When the compound having two or more functional groups S (S-N-S) is a compound having hydroxyl groups at both ends and the maleimide compound having the functional group T (T-MI) is glycidyloxyphenylmaleimide, the hydroxyl groups of the compound having hydroxyl groups at both ends are reacted with the glycidyloxyphenylmaleimide or the like. In this case, sodium hydroxide, potassium hydroxide, potassium carbonate, or the like can be used as a catalyst, and toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetonitrile, dimethylformamide, or the like can be used as a solvent. The reaction temperature is room temperature to 200°C, and the reaction time is 1 to 24 hours. The catalyst is then removed by filtration or the like, and the target compound can be obtained by extraction, solvent removal, or the like. The Diels-Alder reaction of this compound is as described above.

[0274] The aliphatic hydroxy compound is not particularly limited, and examples thereof include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, and 1,16-hexadecane. Examples of the diglycidyl ether include diol, 2-methyl-1,11-undecanediol, 3-methyl-1,11-undecanediol, 2,6,10-trimethyl-1,11-undecanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polypentamethylene glycol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, and polyheptamethylene glycol diglycidyl ether. These may be used alone or in combination of two or more.

[0275] Among these, it is preferable to use a dihydroxy compound having a polyether structure or a linear alkylene chain having 12 to 14 carbon atoms, from the viewpoint of excellent adhesion, flexibility, and dismantling properties of the resulting cured product, and it is most preferable to use polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,12-dodecanediol, 1,13-tridecanediol, or 1,14-tetradecanediol.

[0276] The dihalogenated alkyl compound is not particularly limited, and examples thereof include 1,4-dichlorobutane, 1,5-dichloropentane, 1,6-dichlorohexane, 1,7-dichloroheptane, 1,8-dichlorooctane, 1,9-dichlorononane, 1,10-dichlorodecane, 1,11-dichloroundecane, 1,12-dichlorododecane, 1,4-dibromobutane, 1,5-dibromopentane, 1,6-dibromohexane, 1,7-dibromoheptane, 1,8-dibromooctane, 1,9-dibromononane, 1,10-dibromodecane, 1,11-dibromoundecane, and 1,12-dibromododecane. These compounds may be used alone or in combination of two or more.

[0277] The dihalogenated aralkyl compound is not particularly limited, and examples thereof include dichloroxylene, dichloromethylbiphenyl, dibromoxylene, dibromomethylbiphenyl, etc., and these compounds may be used alone or in combination of two or more.

[0278] The reaction ratio of the aromatic dihydroxy compound to the dihalogenated alkyl compound or the dihalogenated aralkyl compound is preferably in the range of 1 / 1.01 to 1 / 5.0 (molar ratio) of the former / the latter, and from the viewpoint of providing a well-balanced combination of flexibility and heat resistance of the resulting cured product, it is preferable that (a1) / (a2) is 1 / 1.02 to 1 / 3.0 (molar ratio).

[0279] The reaction between the aromatic dihydroxy compound and the dihalogenated alkyl compound or the dihalogenated aralkyl compound is preferably carried out in the presence of a catalyst. Various catalysts can be used, including, for example, alkali (earth) metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide, and alkali metal carbonates such as sodium carbonate and potassium carbonate. These catalysts may be used alone or in combination of two or more. Among these, sodium hydroxide, potassium hydroxide, and potassium carbonate are preferred because they rapidly promote the reaction and are highly effective in reducing the amount of impurities. The amount of these catalysts used is not particularly limited, but is preferably 0.0001 to 10 moles per mole of phenolic hydroxyl groups in the aromatic hydroxy compound. The form of these catalysts is also not particularly limited, and they may be used in the form of an aqueous solution or a solid.

[0280] The reaction of the aromatic dihydroxy compound with the dihalogenated alkyl compound or the dihalogenated aralkyl compound can be carried out in the absence of a solvent or in the presence of an organic solvent. Examples of the organic solvent include those described above in the "Solvent used in the reaction of (a1) and (a2)." The amount of the organic solvent used is usually 50 to 300% by mass, preferably 100 to 1000% by mass, based on the total mass of the raw materials charged. These organic solvents may be used alone or in combination of two or more.

[0281] The reaction temperature when carrying out the reaction is usually room temperature to 150° C., and the reaction time is usually 1 to 24 hours. From the viewpoint of reducing impurities in the final product, the reaction temperature is preferably room temperature to 100° C.

[0282] When the compound (S-N-S) having two or more functional groups S is a compound having halogenated alkyl groups at both ends and the maleimide compound (T-MI) having the functional group T is a hydroxyphenylmaleimide, the halogenated alkyl groups of the compound having halogenated alkyl groups at both ends are reacted with the hydroxyphenylmaleimide or the like. In this case, sodium hydroxide, potassium hydroxide, potassium carbonate, or the like can be used as a catalyst, and toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetonitrile, dimethylformamide, or the like can be used as a solvent. The reaction temperature is room temperature to 200°C, and the reaction time is 1 to 24 hours. The catalyst is then removed by filtration or the like, and the target compound can be obtained by extraction, solvent removal, or the like.

[0283] The obtained Z ３ The maleimide group equivalent weight of the maleimide compound having the structure shown above is preferably 100 to 1,000, more preferably 110 to 800, and even more preferably 120 to 500.

[0284] The obtained Z ３ The melting point of the maleimide compound having the structure is preferably 40 to 250°C, more preferably 50 to 220°C, and even more preferably 60 to 210°C.

[0285] The obtained Z ３ The gelation time at 200°C of the maleimide compound having the structure is preferably 0.5 to 220 minutes, more preferably 1 to 200 minutes, and even more preferably 1.2 to 180 minutes.

[0286] [Curing Agent (F)] The epoxy resin composition according to this embodiment preferably further contains a curing agent (F) capable of reacting with an epoxy group. The curing agent (F) may have a reversible bond. An example of the reversible bond of the curing agent (F) is the reversible bond contained in the glycidyl ether group-containing compound (E).

[0287] The curing agent (F) is not particularly limited as long as it reacts with an epoxy group, and examples thereof include amine compounds, acid anhydrides, amide compounds, phenolic hydroxyl group-containing compounds, carboxylic acid compounds, thiol compounds, etc. Note that the amine compounds do not include the heterocyclic aromatic compound (C) having a tertiary amino group contained in the epoxy resin composition according to this embodiment.

[0288] The curing agent (F) can be appropriately selected depending on the desired physical properties of the cured product. However, from the viewpoint of achieving excellent adhesion, flexibility, and dismantling properties of the resulting cured product, it is preferable to use an amine compound and / or a phenolic hydroxyl group-containing compound.

[0289] Examples of the amine compound include trimethylenediamine, ethylenediamine, N,N,N',N'-tetramethylethylenediamine, pentamethyldiethylenetriamine, triethylenediamine, dipropylenediamine, N,N,N',N'-tetramethylpropylenediamine, tetramethylenediamine, pentanediamine, hexamethylenediamine, trimethylhexamethylenediamine, N,N,N',N'-tetramethylhexamethylenediamine, N,N-dimethylcyclohexylamine, diethylenetriamine (DTA), and triethylenetetramine. aliphatic amine compounds such as tetraethylenepentamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, 1,4-diazabicyclo(2,2,2)octane (triethylenediamine), polyoxyethylenediamine, polyoxypropylenediamine, bis(2-dimethylaminoethyl)ether, dimethylaminoethoxyethoxyethanol, triethanolamine, dimethylaminohexanol, benzylmethylamine, dimethylbenzylamine, m-xylenediamine, and α-methylbenzylmethylamine;

[0290] alicyclic and heterocyclic amine compounds such as piperidine, piperazine, menthanediamine, isophoronediamine, methylmorpholine, ethylmorpholine, N,N',N"-tris(dimethylaminopropyl)hexahydro-s-triazine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxyspiro(5,5)undecane adduct, N-aminoethylpiperazine, trimethylaminoethylpiperazine, bis(4-aminocyclohexyl)methane, N,N'-dimethylpiperazine, and 1,8-diazabicyclo-[5.4.0]-undecene (DBU);

[0291] Aromatic amine compounds such as o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, pyridine, and picoline;

[0292] modified polyamine compounds such as epoxy-modified polyamines (polyamines modified by an epoxy compound addition reaction), Michael addition-modified polyamines (polyamines modified by a Michael addition reaction), Mannich-modified polyamines (polyamines modified by a Mannich addition reaction), thiourea-modified polyamines (polyamines modified by a thiourea addition reaction), and ketone-modified polyamines (polyamines modified by a ketone blocking reaction);

[0293] Examples of the amine compound include dicyandiamide, guanidine, organic acid hydrazides, diaminomaleonitrile, aminimide, boron trifluoride-piperidine complex, boron trifluoride-monoethylamine complex, and other amine compounds.

[0294] Examples of the acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, maleic anhydride polypropylene glycol, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0295] Examples of the amide compound include polyamidoamine, etc. Examples of the polyamidoamine include those obtained by reacting an aliphatic polyamine or a polyamine having a polyoxyalkylene chain.

[0296] The phenolic hydroxyl group-containing compound is not particularly limited, and examples thereof include the same specific examples as those of the aromatic hydroxy compound (a2).

[0297] Examples of the carboxylic acid compound include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and azelaic acid, carboxylic acid compounds such as fatty acids and dimer acids, and carboxylic acid polymers such as carboxylic acid-terminated polyesters, polyacrylic acid, maleic acid-modified polypropylene glycol, and copolymers of styrene and maleic anhydride.

[0298] The thiol compound preferably contains two or more thiol groups per molecule, and examples thereof include 3,3'-dithiodipropionic acid, trimethylolpropane tris(thioglycolate), pentaerythritol tetrakis(thioglycolate), ethylene glycol dithioglycolate, 1,4-bis(3-mercaptobutyryloxy)butane, tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), dipentaerythritol hexakis(3-mercaptopropionate), 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, 4-butanedithiol, 1,6-hexaneedithiol, and 1,10-decanedithiol.

[0299] When the curing agent (F) is used, the curing agent may be used alone or in combination of two or more types. It is preferable to use the amine compounds, acid anhydrides, and / or carboxylic acid compounds in applications such as underfill materials and general coating applications. Furthermore, in applications such as adhesives and flexible wiring boards, the amine compounds, particularly dicyandiamide, are preferred in terms of workability, curability, and long-term stability. Furthermore, in applications such as semiconductor encapsulation materials, solid phenolic hydroxyl group-containing compounds are preferred in terms of the heat resistance of the cured product. Furthermore, in applications requiring low-temperature curing, such as adhesives for batteries, the aliphatic amine compounds and thiol compounds are preferred.

[0300] Furthermore, when the epoxy resin composition according to the present embodiment contains the glycidyl ether group-containing compound (E), the curing agent (F) is preferably an amino group-containing compound and / or a phenolic hydroxyl group-containing compound having a reversible bond, from the viewpoint of being able to further exhibit its effects.

[0301] Examples of the amino group-containing compound having a reversible bond include an amino group-containing compound in which a structural unit V' and a structural unit W' are linked via V'-W'-V'. The structural unit V' has a structure having one or more amino groups, and the structural unit V' and the structural unit W' are different. The structural unit V' and the structural unit W' are bonded via the reversible bond. Examples of the reversible bond include the same as the reversible bond in the glycidyl ether group-containing compound (E) in this embodiment. That is, the structural unit V' and the structural unit W' may be bonded via a reversible bond formed by a Diels-Alder reaction between a furan structure and a maleimide structure.

[0302] Examples of the phenolic hydroxyl group-containing compound having a reversible bond include a phenolic hydroxyl group-containing compound in which a structural unit V' and a structural unit W' are linked via V'-W'-V'. The structural unit V' has a structure having one or more hydroxyl groups, and the structural unit V' and the structural unit W' are different. The structural unit V' and the structural unit W' are bonded via the reversible bond. Examples of the reversible bond include the same as the reversible bond in the glycidyl ether group-containing compound (E) in this embodiment. That is, the structural unit V' and the structural unit W' may be bonded via a reversible bond formed by a Diels-Alder reaction between a furan structure and a maleimide structure.

[0303] [Other Epoxy Resins] Furthermore, the epoxy resin composition according to this embodiment can contain epoxy resins other than the epoxy resin (A), the epoxy resin (B), and the glycidyl ether group-containing compound (E) according to this embodiment, as long as the effects of this embodiment are not impaired. When the epoxy resin composition according to this embodiment does not contain the glycidyl ether group-containing compound (E), the total amount of the epoxy resin (A) and the epoxy resin (B) in the epoxy resin composition according to this embodiment is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and particularly preferably 80% by mass or more, based on the total epoxy resins. When the epoxy resin composition according to this embodiment contains the glycidyl ether group-containing compound (E), the total amount of the epoxy resin (A), the epoxy resin (B), and the glycidyl ether group-containing compound (E) in the epoxy resin composition according to this embodiment is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and particularly preferably 80% by mass or more, based on the total epoxy resins.

[0304] The other epoxy resins are not limited in any way as long as they do not belong to the epoxy resin (A), the epoxy resin (B), or the glycidyl ether group-containing compound (E), and examples thereof include liquid epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD ​​type epoxy resins, polyhydroxybenzene type epoxy resins, polyhydroxynaphthalene type epoxy resins, biphenyl type epoxy resins, and tetramethylbiphenyl type epoxy resins; brominated epoxy resins such as brominated phenol novolac type epoxy resins; solid bisphenol A type epoxy resins; and phenol novolac type epoxy resins. Examples of epoxy resins include cresol novolac type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, dicyclopentadiene-phenol addition reaction type epoxy resins, phenol aralkyl type epoxy resins, phenylene ether type epoxy resins, naphthylene ether type epoxy resins, naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins, and biphenyl-modified novolac type epoxy resins. These may be used alone or in combination of two or more, and it is preferable to select and use various types depending on the intended use, the physical properties of the cured product, and the like.

[0305] The concentration of reversible bonds in the epoxy resin composition according to this embodiment is preferably 0.10 mmol / g or more, relative to the total mass of the curable components in the epoxy resin composition. This configuration further improves the adhesion, flexibility, and dismantling properties of the cured product obtained from the epoxy resin composition. The concentration of the reversible bonds is more preferably 0.10 to 3.00 mmol / g, and even more preferably 0.15 to 2.00 mmol / g. Furthermore, when the glycidyl ether group-containing compound (E) contains multiple reversible bonds, or when the phenolic hydroxyl group-containing compound having the reversible bonds is used alone or in combination with another curing agent as the curing agent, the total concentration of the reversible bonds is preferably 0.10 mmol / g or more, more preferably 0.10 to 3.00 mmol / g, and even more preferably 0.15 to 2.00 mmol / g, relative to the total mass of the curable components in the epoxy resin composition. The concentration of the reversible bond can be appropriately selected based on the glass transition temperature, defined by the tan δ peak top of the target cured product measured by a dynamic mechanical analyzer (DMA). For example, when the glass transition temperature is used as a guideline, if the glass transition temperature of the cured product is near room temperature, sufficient adhesiveness, flexibility, and dismantling properties are likely to be exhibited even at the low concentration side of the preferred range. On the other hand, if the glass transition temperature of the target cured product is above 100°C as a guideline, the functions are likely to be exhibited at the high concentration side of the preferred range. However, in the temperature range above the glass transition temperature measured by DMA, molecular mobility is generally high, and sufficient adhesiveness, flexibility, and dismantling properties are likely to be exhibited even at a low concentration of the glycidyl ether group-containing compound (E). Therefore, for example, the effects of exhibiting adhesiveness, flexibility, and dismantling properties can be adjusted by appropriately adjusting the aging temperature for repair or the heating temperature for remolding. Thus, the relationship between the glass transition temperature of the cured product and the concentration of the reversible bond is not limited to these.

[0306] The ratio of the total epoxy groups to the total functional groups reactive with these epoxy groups in the epoxy resin composition according to this embodiment is not particularly limited, but in terms of good mechanical properties, etc. of the resulting cured product, it is preferable that the amount of functional groups reactive with epoxy groups be 0.4 to 1.5 equivalents per equivalent of the total epoxy groups in the resin composition. The functional groups reactive with epoxy groups include functional groups such as hydroxyl groups and amino groups contained in the curing agent (F).

[0307] [Curing Accelerator] The epoxy resin composition according to this embodiment may contain a curing accelerator that does not belong to the heterocyclic aromatic compound (C) having a tertiary amino group. Various curing accelerators can be used, including, for example, urea compounds, phosphorus compounds, tertiary amines, organic acid metal salts, Lewis acids, and amine complex salts.

[0308] Examples of the urea compound include p-chlorophenyl-N,N-dimethylurea, 3-phenyl-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-N,N-dimethylurea, and N-(3-chloro-4-methylphenyl)-N',N'-dimethylurea.

[0309] Examples of the phosphorus compound include alkyl phosphines such as ethylphosphine and butylphosphine, primary phosphines such as phenylphosphine, dialkyl phosphines such as dimethylphosphine and dipropylphosphine, secondary phosphines such as diphenylphosphine and methylethylphosphine, and tertiary phosphines such as trimethylphosphine, triethylphosphine and triphenylphosphine.

[0310] Examples of the tertiary amine include tertiary amines such as triethylamine, N,N-dimethylbenzylamine, N,N-diethylbenzylamine, 1,8-diazabicyclo[5.4.0]undecene, and 1,4-diazabicyclo[2.2.2]octane.

[0311] Examples of the organic acid metal salts include organic acid cobalt salts such as cobalt thiocyanate, cobalt octylate, cobalt naphthenate, and cobalt acetate; organic acid copper salts such as copper naphthenate; organic acid manganese salts such as manganese naphthenate; and organic acid vanadium salts such as vanadyl naphthenate and vanadyl stearate.

[0312] Examples of the Lewis acid include complexes of boron halides and bases, such as boron trifluoride-piperidine complex, boron trifluoride-monoethylamine complex, boron trifluoride-triethanolamine complex, and boron trichloride-octylamine complex.

[0313] Examples of the amine complex salt include boron trifluoride complexes such as boron trifluoride monoethylamine complex, boron trifluoride diethylamine complex, boron trifluoride isopropylamine complex, boron trifluoride chlorophenylamine complex, boron trifluoride benzylamine complex, boron trifluoride aniline complex, and mixtures thereof.

[0314] When used as an adhesive, a urea compound, particularly 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), is preferred because of its excellent workability and low-temperature curing properties.When used as a semiconductor encapsulation material, a phosphorus compound such as triphenylphosphine and a tertiary amine such as 1,8-diazabicyclo-[5.4.0]-undecene (DBU) are preferred because of their excellent curing properties, heat resistance, electrical properties, and moisture resistance reliability.

[0315] [Other Thermosetting Resins and Thermoplastic Resins] The epoxy resin composition according to this embodiment may be used in combination with other thermosetting resins or thermoplastic resins within a range that does not impair the effects of this embodiment.

[0316] Examples of other thermosetting resins include cyanate ester resins, resins having a benzoxazine structure, active ester resins, vinylbenzyl compounds, acrylic compounds, etc. When the other thermosetting resins described above are used in combination, the amount used is not particularly limited as long as it does not impair the effects of this embodiment, but is preferably in the range of 1 to 50 parts by mass per 100 parts by mass of the epoxy resin composition.

[0317] Examples of the cyanate ester resin include bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, bisphenol E type cyanate ester resin, bisphenol S type cyanate ester resin, bisphenol sulfide type cyanate ester resin, phenylene ether type cyanate ester resin, naphthylene ether type cyanate ester resin, biphenyl type cyanate ester resin, tetramethylbiphenyl type cyanate ester resin, polyhydroxynaphthalene type cyanate ester resin, phenol novolac type cyanate ester resin, cresol novolac Examples of the cyanate ester resin include phenol-type cyanate ester resins, triphenylmethane-type cyanate ester resins, tetraphenylethane-type cyanate ester resins, dicyclopentadiene-phenol addition reaction-type cyanate ester resins, phenol aralkyl-type cyanate ester resins, naphthol novolac-type cyanate ester resins, naphthol aralkyl-type cyanate ester resins, naphthol-phenol co-condensed novolac-type cyanate ester resins, naphthol-cresol co-condensed novolac-type cyanate ester resins, biphenyl-modified novolac-type cyanate ester resins, and anthracene-type cyanate ester resins. These may be used alone or in combination of two or more.

[0318] Among the cyanate ester resins, bisphenol A-type cyanate ester resins, bisphenol F-type cyanate ester resins, bisphenol E-type cyanate ester resins, polyhydroxynaphthalene-type cyanate ester resins, naphthylene ether-type cyanate ester resins, and novolac-type cyanate ester resins are preferred in terms of the ability to obtain cured products with particularly excellent heat resistance, and dicyclopentadiene-phenol addition reaction-type cyanate ester resins are preferred in terms of the ability to obtain cured products with excellent dielectric properties.

[0319] The resin having a benzoxazine structure is not particularly limited, and examples thereof include a reaction product of bisphenol F, formalin, and aniline (Fa-type benzoxazine resin), a reaction product of diaminodiphenylmethane, formalin, and phenol (P-d-type benzoxazine resin), a reaction product of bisphenol A, formalin, and aniline, a reaction product of dihydroxydiphenyl ether, formalin, and aniline, a reaction product of diaminodiphenyl ether, formalin, and phenol, a reaction product of a dicyclopentadiene-phenol addition type resin, formalin, and aniline, a reaction product of phenolphthalein, formalin, and aniline, a reaction product of diphenyl sulfide, formalin, and aniline, etc. These may be used alone or in combination of two or more.

[0320] The active ester resin is not particularly limited, but compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are generally preferred. The active ester resin is preferably one obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. From the viewpoint of improving heat resistance in particular, active ester resins obtained from a carboxylic acid compound or its halide and a hydroxy compound are preferred, and active ester resins obtained from a carboxylic acid compound and / or its halide and a phenol compound and / or a naphthol compound are more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, and the like, or halides thereof. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, dihydroxydiphenyl ether, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, and dicyclopentadiene-phenol adduct resins.

[0321] Specific examples of the active ester resin include active ester resins containing a dicyclopentadiene-phenol addition structure, active ester resins containing a naphthalene structure, active ester resins which are acetylated phenol novolac, and active ester resins which are benzoylated phenol novolac. Of these, active ester resins containing a dicyclopentadiene-phenol addition structure and active ester resins containing a naphthalene structure are more preferred in terms of their excellent ability to improve peel strength.

[0322] Furthermore, various vinyl polymers may be used in combination. Examples of the various vinyl polymers include homopolymers of vinyl compounds such as polyhydroxystyrene, polystyrene, polyvinylnaphthalene, polyvinylanthracene, polyvinylcarbazole, polyindene, polyacenaphthylene, polynorbornene, polycyclodecene, polytetracyclododecene, polynortricyclene, and poly(meth)acrylate, and copolymers thereof.

[0323] The thermoplastic resin refers to a resin that can be melt-molded by heating. Specific examples thereof include polyethylene resin, polypropylene resin, polystyrene resin, rubber-modified polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate (PMMA) resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyethylene terephthalate resin, ethylene vinyl alcohol resin, cellulose acetate resin, ionomer resin, polyacrylonitrile resin, polyamide resin, polyacetal resin, polybutylene terephthalate resin, polylactic acid resin, polyphenylene ether resin, modified polyphenylene ether resin, polycarbonate resin, polysulfone resin, polyphenylene sulfide (PPS) resin, polyetherimide resin, polyethersulfone resin, polyarylate resin, thermoplastic polyimide resin, polyamideimide resin, polyetheretherketone resin, polyketone resin, liquid crystal polyester resin, fluororesin, syndiotactic polystyrene resin, and cyclic polyolefin resin. These thermoplastic resins can be used alone or in combination of two or more.

[0324] When the other resin is used and when the glycidyl ether group-containing compound (E) is contained, the blending ratio of the glycidyl ether group-containing compound (E) of the present embodiment to the other resin can be set arbitrarily depending on the application. However, from the viewpoint of excellent adhesion, flexibility, and dismantling property when formed into a cured product, the blending ratio is preferably such that the other resin is 0.5 to 100 parts by mass per 100 parts by mass of the total of the epoxy resin (A), the epoxy resin (B), and the glycidyl ether group-containing compound (E).

[0325] [Non-Halogen Flame Retardant] When the epoxy resin composition according to the present embodiment is used in an application requiring high flame retardancy, a non-halogen flame retardant that contains substantially no halogen atoms may be blended therein.

[0326] Examples of the non-halogen flame retardant include phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organic metal salt-based flame retardants. There are no limitations on the use of these flame retardants, and they may be used alone or in combination of two or more.

[0327] The phosphorus-based flame retardant can be either an inorganic compound or an organic phosphorus-based compound, and examples of the inorganic compound include red phosphorus, ammonium phosphates such as monoammonium phosphate, diammonium phosphate, triammonium phosphate, and ammonium polyphosphate, and inorganic nitrogen-containing phosphorus compounds such as phosphoric acid amide.

[0328] The red phosphorus is preferably surface-treated to prevent hydrolysis and the like. Examples of the surface treatment method include (i) a method of coating with an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide, bismuth oxide, bismuth hydroxide, bismuth nitrate, or a mixture thereof; (ii) a method of coating with a mixture of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, or titanium hydroxide, and a thermosetting resin such as a phenolic resin; and (iii) a method of doubly coating with a thermosetting resin such as a phenolic resin on a coating of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, or titanium hydroxide.

[0329] Examples of the organic phosphorus compound include general-purpose organic phosphorus compounds such as phosphate ester compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphorane compounds, and organic nitrogen-containing phosphorus compounds, as well as cyclic organic phosphorus compounds such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-(2,7-dihydroxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and derivatives thereof obtained by reacting these with compounds such as epoxy resins and phenolic resins.

[0330] The amount of the phosphorus-based flame retardant to be blended is appropriately selected depending on the type of phosphorus-based flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, when red phosphorus is used as the non-halogenated flame retardant, it is preferably blended in an amount within a range of 0.1 to 2.0 parts by mass, relative to 100 parts by mass of the epoxy resin composition according to this embodiment. Similarly, when an organic phosphorus compound is used, it is preferably blended in an amount within a range of 0.1 to 10.0 parts by mass, and more preferably in an amount within a range of 0.5 to 6.0 parts by mass.

[0331] When the phosphorus-based flame retardant is used, the phosphorus-based flame retardant may be used in combination with hydrotalcite, magnesium hydroxide, boron compounds, zirconium oxide, black dyes, calcium carbonate, zeolite, zinc molybdate, activated carbon, or the like.

[0332] Examples of the nitrogen-based flame retardant include triazine compounds, cyanuric acid compounds, isocyanuric acid compounds, and phenothiazines, and among these, triazine compounds, cyanuric acid compounds, and isocyanuric acid compounds are preferred.

[0333] Examples of the triazine compounds include melamine, acetoguanamine, benzoguanamine, melon, melam, succinoguanamine, ethylenedimelamine, melamine polyphosphate, triguanamine, and the like, as well as (1) aminotriazine sulfate compounds such as guanylmelamine sulfate, melem sulfate, and melam sulfate; (2) co-condensates of phenols such as phenol, cresol, xylenol, butylphenol, and nonylphenol with melamines such as melamine, benzoguanamine, acetoguanamine, and formguanamine and formaldehyde; (3) mixtures of the co-condensates of (2) with phenolic resins such as phenol-formaldehyde condensates; and (4) compounds obtained by further modifying (2) or (3) with tung oil, isomerized linseed oil, or the like.

[0334] Examples of the cyanuric acid compound include cyanuric acid and melamine cyanurate.

[0335] The amount of the nitrogen-based flame retardant to be added is appropriately selected depending on the type of nitrogen-based flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, the amount is preferably in the range of 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the epoxy resin composition according to this embodiment.

[0336] When the nitrogen-based flame retardant is used, a metal hydroxide, a molybdenum compound, or the like may be used in combination.

[0337] The silicone flame retardant can be any organic compound containing silicon atoms, and examples thereof include silicone oil, silicone rubber, and silicone resin. The amount of the silicone flame retardant to be added is selected appropriately depending on the type of silicone flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, it is preferable to add the silicone flame retardant in an amount of 0.05 to 20 parts by mass per 100 parts by mass of the resin composition containing the non-halogen flame retardant and other fillers and additives. When using the silicone flame retardant, a molybdenum compound, alumina, or the like may also be used in combination.

[0338] Examples of the inorganic flame retardant include metal hydroxides, metal oxides, metal carbonate compounds, metal powders, boron compounds, and low-melting glass.

[0339] Examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, and zirconium hydroxide.

[0340] Examples of the metal oxide include zinc molybdate, molybdenum trioxide, zinc stannate, tin oxide, aluminum oxide, iron oxide, titanium oxide, manganese oxide, zirconium oxide, zinc oxide, molybdenum oxide, cobalt oxide, bismuth oxide, chromium oxide, nickel oxide, copper oxide, and tungsten oxide.

[0341] Examples of the metal carbonate compound include zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, basic magnesium carbonate, aluminum carbonate, iron carbonate, cobalt carbonate, and titanium carbonate.

[0342] Examples of the metal powder include aluminum, iron, titanium, manganese, zinc, molybdenum, cobalt, bismuth, chromium, nickel, copper, tungsten, and tin.

[0343] Examples of the boron compound include zinc borate, zinc metaborate, barium metaborate, boric acid, borax, and boric acid esters.

[0344] The low-melting glass may be, for example, Seapley manufactured by Air Brown Co., Ltd., or hydrated glass SiO ２ -MgO-H ２ O, PbO-B ２ O ３ system, ZnO-P ２ O ５ -MgO series, P ２ O ５ -B ２ O ３ -PbO-MgO system, P-Sn-O-F system, PbO-V ２ O ５ -TeO ２ system, Al ２ O ３-H ２ Examples of suitable glass compounds include lead O-based and lead borosilicate-based glass compounds.

[0345] The amount of the inorganic flame retardant to be blended is selected as appropriate depending on the type of inorganic flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, the amount is preferably in the range of 0.05 to 20 parts by mass, and more preferably in the range of 0.5 to 15 parts by mass, per 100 parts by mass of the resin composition containing the non-halogen flame retardant and all of the other fillers and additives.

[0346] Examples of the organometallic salt flame retardant include ferrocene, acetylacetonate metal complexes, organometallic carbonyl compounds, organic cobalt salt compounds, organic sulfonic acid metal salts, and compounds in which a metal atom is ionic-bonded and / or coordinate-bonded to an aromatic compound and / or a heterocyclic compound.

[0347] The amount of the organometallic salt flame retardant to be blended is appropriately selected depending on the type of organometallic salt flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, it is preferable to blend the amount in the range of 0.005 parts by mass to 10 parts by mass per 100 parts by mass of the resin composition containing all of the non-halogen flame retardant and the other fillers, additives, etc.

[0348] [Filler] The epoxy resin composition according to this embodiment may contain a filler that does not belong to the thermally expandable particles (D) according to this embodiment. Examples of the filler include inorganic fillers and organic fillers. Examples of the inorganic filler include inorganic fine particles.

[0349] Examples of the inorganic fine particles include those with excellent heat resistance such as alumina, magnesia, titania, zirconia, and silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, and ultrafine amorphous silica); those with excellent thermal conductivity such as boron nitride, aluminum nitride, aluminum oxide, titanium oxide, magnesium oxide, zinc oxide, silicon oxide, and diamond; those with excellent electrical conductivity such as metal fillers and / or metal-coated fillers using metals or alloys (e.g., iron, copper, magnesium, aluminum, gold, silver, platinum, zinc, manganese, and stainless steel); and those with excellent barrier properties such as minerals such as mica, clay, kaolin, talc, zeolite, wollastonite, and smectite, potassium titanate, magnesium sulfate, sepiolite, and zonolite. Examples of inorganic particles include iodide, aluminum borate, calcium carbonate, titanium oxide, barium sulfate, zinc oxide, and magnesium hydroxide; those with a high refractive index include barium titanate, zirconia oxide, and titanium oxide; those exhibiting photocatalytic properties include photocatalytic metals such as titanium, cerium, zinc, copper, aluminum, tin, indium, phosphorus, carbon, sulfur, ruthenium, nickel, iron, cobalt, silver, molybdenum, strontium, chromium, barium, and lead, as well as composites of these metals and oxides thereof; those with excellent wear resistance include metals such as silica, alumina, zirconia, and magnesium oxide, as well as composites and oxides thereof; those with excellent conductivity include metals such as silver and copper, tin oxide, and indium oxide; those with excellent insulation properties include silica; and those with excellent ultraviolet shielding properties include titanium oxide and zinc oxide. These inorganic particles can be selected appropriately depending on the application, and can be used alone or in combination. Furthermore, the inorganic particles have various properties in addition to those listed as examples, so they can be selected appropriately depending on the application.

[0350] When silica is used as the inorganic fine particles, for example, there is no particular limitation, and known silica fine particles such as powdered silica and colloidal silica can be used. Examples of commercially available powdered silica fine particles include silica fine particles manufactured by Nippon Aerosil Co., Ltd. (product names: Aerosil 50, 200), silica fine particles manufactured by AGC Inc. (product names: Sildex H31, H32, H51, H52, H121, H122), silica fine particles manufactured by Nippon Silica Industry Co., Ltd. (product names: E220A, E220), silica fine particles manufactured by Fuji Silysia Chemical Ltd. (product name: SYLYSIA470), and silica fine particles manufactured by Nippon Sheet Glass Co., Ltd. (product name: SG Flake).

[0351] Examples of commercially available colloidal silica include methanol silica sol manufactured by Nissan Chemical Industries, Ltd. (trade names: IPA-ST, MEK-ST, NBA-ST, XBA-ST, DMAC-ST, ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, and ST-OL).

[0352] The silica fine particles may be surface-modified silica fine particles. For example, the silica fine particles may be surface-treated with a reactive silane coupling agent having a hydrophobic group, or modified with a compound having a (meth)acryloyl group. Examples of commercially available powdered silica modified with a compound having a (meth)acryloyl group include silica (trade names: Aerosil RM50, R711) manufactured by Nippon Aerosil Co., Ltd., and examples of commercially available colloidal silica modified with a compound having a (meth)acryloyl group include colloidal silica (trade name: MIBK-SD) manufactured by Nissan Chemical Industries, Ltd.

[0353] The shape of the silica fine particles is not particularly limited, and spherical, hollow, porous, rod-like, plate-like, fibrous, or irregular shapes can be used. The primary particle diameter is preferably in the range of 5 to 200 nm.

[0354] The titanium oxide fine particles can be used not only as extender pigments but also as ultraviolet light-responsive photocatalysts, such as anatase titanium oxide, rutile titanium oxide, and brookite titanium oxide. Furthermore, particles designed to respond to visible light by doping different elements into the crystalline structure of titanium oxide can also be used. Suitable elements for doping titanium oxide include anionic elements such as nitrogen, sulfur, carbon, fluorine, and phosphorus, and cationic elements such as chromium, iron, cobalt, and manganese. The titanium oxide fine particles can be used in the form of powder, sol, or slurry dispersed in an organic solvent or water. Examples of commercially available powdered titanium oxide fine particles include Aerosil (trade name: P-25) manufactured by Nippon Aerosil Co., Ltd. and titanium oxide fine particles (trade name: ATM-100) manufactured by Teika Corporation. Examples of commercially available slurry titanium oxide fine particles include titanium oxide fine particles (trade name: TKD-701) manufactured by Teika Corporation.

[0355] Examples of the organic filler include polyacrylate particles, core-shell type polyacrylate particles, polystyrene particles, acrylic-styrene copolymer particles, polypropylene particles, polyethylene particles, and the like.

[0356] [Fibrous Substrate] The epoxy resin composition according to the present embodiment may further contain a fibrous substrate. The fibrous substrate is not particularly limited, but is preferably one used in fiber-reinforced resins, such as inorganic fibers and organic fibers.

[0357] Examples of the inorganic fibers include inorganic fibers such as carbon fibers, glass fibers, boron fibers, alumina fibers, and silicon carbide fibers, as well as carbon fibers, activated carbon fibers, graphite fibers, tungsten carbide fibers, silicon carbide fibers (silicon carbide fibers), ceramic fibers, natural fibers, mineral fibers such as basalt, boron nitride fibers, boron carbide fibers, and metal fibers. Examples of the metal fibers include aluminum fibers, copper fibers, brass fibers, stainless steel fibers, and steel fibers.

[0358] Examples of the organic fibers include synthetic fibers made of resin materials such as polybenzazole, aramid, PBO (polyparaphenylene benzoxazole), polyphenylene sulfide, polyester, acrylic, polyamide, polyolefin, polyvinyl alcohol, and polyarylate; natural fibers such as cellulose, pulp, cotton, wool, and silk; and regenerated fibers such as protein, polypeptide, and alginic acid.

[0359] Among these, the carbon fiber and the glass fiber are preferred because they have a wide range of industrial applications. The fibrous substrate may be used alone or in combination of two or more types.

[0360] The fibrous substrate may be an assembly of fibers, with continuous or discontinuous fibers, in the form of a woven or nonwoven fabric, a fiber bundle in which fibers are aligned in one direction, or a sheet in which fiber bundles are arranged, or a three-dimensional shape in which a thickness is added to an assembly of fibers.

[0361] [Dispersion Medium] The epoxy resin composition according to this embodiment may contain a dispersion medium for the purpose of adjusting the solid content and viscosity of the resin composition. The dispersion medium may be any liquid medium that does not impair the effects of this embodiment, and examples of the dispersion medium include various organic solvents and liquid organic polymers.

[0362] Examples of the organic solvent to be used include the solvents described above in the section "Solvent to be used in the reaction of (a1) and (a2)." These can be used alone or in combination, but among them, methyl ethyl ketone is preferred from the viewpoints of volatility during coating and solvent recovery.

[0363] The liquid organic polymer is a liquid organic polymer that does not directly contribute to the curing reaction, and examples thereof include an acrylic polymer (FLOWLEN WK-20: Kyoeisha Chemical), an amine salt of a special modified phosphate ester (HIPLAAD ED-251: Kusumoto Chemicals), and a modified acrylic block copolymer (DISPERBYK2000; BYK).

[0364] [Other Compounds] The resin composition of the present embodiment may contain other compounds, such as a catalyst, a polymerization initiator, an inorganic pigment, an organic pigment, an extender pigment, a clay mineral, a wax, a surfactant, a stabilizer, a flow adjuster and pulling agent, a dye, a leveling agent, a rheology control agent, an ultraviolet absorber, an antioxidant, a flame retardant, a plasticizer, and a reactive diluent.

[0365] A cured product can be obtained by curing the resin composition of the present embodiment. When curing, curing may be performed at room temperature or by heating. When performing thermal curing, curing may be performed by a single heating step or by multiple heating steps.

[0366] The epoxy resin composition according to this embodiment can also be cured by active energy rays. In this case, a photocationic polymerization initiator may be used as the polymerization initiator. Examples of active energy rays that can be used include visible light, ultraviolet light, X-rays, and electron beams.

[0367] Examples of the photocationic polymerization initiator include aryl-sulfonium salts and aryl-iodonium salts, and specifically, arylsulfonium hexafluorophosphate, arylsulfonium hexafluoroantimonate, arylsulfonium tetrakis(pentafluoro)borate, tri(alkylphenyl)sulfonium hexafluorophosphate, etc. The photocationic polymerization initiators may be used alone or in combination of two or more.

[0368] [Method for Preparing Epoxy Resin Composition] The epoxy resin composition according to this embodiment can be prepared by uniformly mixing the above-mentioned components, and the method for doing so is not particularly limited. For example, the composition can be prepared by uniformly mixing the components using a pot mill, ball mill, bead mill, roll mill, homogenizer, super mill, homodisper, universal mixer, Banbury mixer, kneader, etc.

[0369] The epoxy resin composition according to this embodiment comprises the epoxy resin (A), the epoxy resin (B), optionally the heterocyclic aromatic compound (C) having a tertiary amino group, the thermally expandable particles (D), optionally the glycidyl ether group-containing compound (E), the curing agent (F), and optionally the curing agent, filler, fibrous substrate, dispersion medium, and resins other than the various compounds described above. These components may be dissolved in a dispersion medium such as the organic solvent described above, or may be mixed and dispersed under solvent-free conditions (no solvent is used). Mixing and dispersion under solvent-free conditions (no solvent is used) is preferred. The epoxy resin composition according to this embodiment may also be in a state where the components are uniformly mixed. Mixing is preferably performed using a mixer or the like. The blending ratio of each component can be adjusted appropriately depending on the desired properties of the cured product, such as mechanical strength and heat resistance. The order in which the components are mixed is not particularly limited when preparing the epoxy resin composition.

[0370] (Cured Product of Epoxy Resin Composition According to the Present Embodiment) The cured product of the epoxy resin composition according to the present embodiment is obtained by curing a composition containing the epoxy resin composition according to the present embodiment and, if necessary, the curing agent (F). The curing method can be appropriately selected from known methods.

[0371] The cured product of the present embodiment is cured using the epoxy resin composition of the present embodiment as described above, and therefore exhibits an appropriate crosslink density, thereby allowing the product to maintain good mechanical strength.

[0372] The epoxy resin cured product obtained from the epoxy resin (A), the epoxy resin (B), and optionally the compound (C) and the thermally expandable particles (D) exhibits excellent adhesion, flexibility, and dismantling properties, and also exhibits excellent adhesion and dismantling properties after a heat resistance test. This is thought to be due to the uneven distribution of the compound (C) on the surface of the cured product. In particular, when the substrate to be bonded is a metal (e.g., iron, aluminum, etc.), the substrate surface is coordinate-bonded with the compound (C), improving adhesive strength, and dissociating the coordinate bond by heat is thought to have the effect of exhibiting dismantling properties. Due to the effect of this coordinate bond, it is thought that the initial adhesion and dismantling properties are excellent, and that the adhesion and dismantling properties are also excellent after a heat resistance test.

[0373] The structure of the resulting cured product can be confirmed by infrared absorption (IR) spectroscopy using Fourier transform infrared spectroscopy (FT-IR) or the like, elemental analysis, X-ray scattering, or the like.

[0374] When the epoxy resin composition according to this embodiment contains the glycidyl ether group-containing compound (E), the cured product according to this embodiment can be obtained by using the glycidyl ether group-containing compound (E) according to this embodiment as one component of the epoxy resin composition, as described above. However, it is also possible to use the aforementioned conjugated diene intermediate, which is an intermediate of the glycidyl ether group-containing compound (E), in combination with a compound capable of undergoing an addition reaction by Diels-Alder reaction, and form the glycidyl ether group-containing compound (E) while it is being formed (synthesized in situ) during the curing process to obtain a cured product.

[0375] For example, when a curing reaction is carried out using the compound represented by formula (1)', a furan having a glycidyl ether group, and a curing agent (F) as essential raw materials in a temperature range where the Retro-Diels-Alder reaction does not occur, the glycidyl ether group-containing compound (E) represented by formula (4) can be obtained during the curing reaction, and as the curing reaction progresses, a cured product can be obtained. The furan compound having a glycidyl ether group that can be used in this case is the same as described above.

[0376] The epoxy resin composition according to this embodiment and a cured product produced from the epoxy resin composition have adhesiveness, flexibility, and dismantling properties.

[0377] The present invention will now be described in more detail with reference to examples and comparative examples, in which "parts" and "%" are by mass unless otherwise specified. The present invention is not limited thereto.

[0378] １ H and １３ C-NMR, FD-MS spectrum, and GPC were measured under the following conditions.

[0379] １ H-NMR: JEOL RESONANCE "JNM-ECA600" Magnetic field strength: 600 MHz Number of accumulations: 32 Solvent: DMSO-d ６ Sample concentration: 30% by mass

[0380] １３ C-NMR: JEOL RESONANCE "JNM-ECA600" Magnetic field strength: 150 MHz Number of accumulations: 320 Solvent: DMSO-d ６ Sample concentration: 30% by mass

[0381] FD-MS: "JMS-T100GC AccuTOF" manufactured by JEOL Ltd. Measurement range: m / z = 50.00 to 2000.00 Rate of change: 25.6 mA / min Final current value: 40 mA Cathode voltage: -10 kV

[0382] GPC: "HLC-8320GPC" manufactured by Tosoh Corporation Column: "TSK-GEL G2000HXL" + "TSK-GEL G3000HXL" + "TSK-GEL G4000HXL" manufactured by Tosoh Corporation Detector: RI (differential refractometer) Measurement conditions: 40°C Mobile phase: tetrahydrofuran Flow rate: 1 ml / min Standard: "PStQuick A", "PStQuick B", "PStQuick E", "PStQuick F" manufactured by Tosoh Corporation

[0383] Scanning electron microscope (SEM): KEYENCE VE-9800 Measurement conditions: Measurement magnification: 5,000 times Acceleration voltage: 5 kV ​​​

[0384] The epoxy equivalent, viscosity, and total chlorine content of the epoxy resin were measured by the following methods: Epoxy equivalent (g / equivalent): JIS K7236 Viscosity: JIS K7233 Single cylinder rotational viscometer method Total chlorine content: JIS K7243-3

[0385] The number of repeating units can be calculated, for example, from the results of GPC molecular weight measurement, or various appropriate instrumental analyses such as FD-MS and NMR.

[0386] (Synthesis Example 1) 210 g of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g / equivalent) and 123.1 g of bisphenol A (hydroxyl equivalent 114 g / equivalent) were charged into a flask equipped with a thermometer and a stirrer, and the temperature was raised to 140°C over 30 minutes. 3.4 g of 20% aqueous sodium hydroxide solution was then charged. The temperature was then raised to 150°C over 30 minutes, and the mixture was further reacted at 150°C for 16 hours. A neutralizing amount of sodium phosphate was then added to obtain a hydroxy compound (Ph-1). Mass spectrometry of this hydroxy compound (Ph-1) revealed a peak of M+ = 771, which corresponds to the theoretical structure of m1 = 1, n1 = 12 in the following structural formula (Ph-1), confirming that it contained the target hydroxy compound. The phenolic hydroxyl group equivalent of this hydroxy compound (Ph-1) was 1980 g / equivalent.

[0387]

[0388] Synthesis Example 2 The same reaction as in Synthesis Example 1 was carried out, except that 210 g (0.5 mol) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g / equivalent) and 119.7 g (0.53 mol) of bisphenol A (hydroxyl equivalent 114 g / equivalent) in Synthesis Example 1 were changed to 481 g (0.5 mol) of polypropylene glycol diglycidyl ether (manufactured by Nagase ChemteX Co., Ltd.: epoxy equivalent 481 g / equivalent) and 136.8 g (0.6 mol) of bisphenol A (hydroxyl equivalent 114 g / equivalent), thereby obtaining 585 g of a hydroxy compound (Ph-2). This hydroxy compound (Ph-2) was confirmed to contain the target hydroxy compound because a peak at M+ = 1226 was obtained in the mass spectrum, which corresponds to the theoretical structure of the following structural formula (Ph-2) in which m = 1 and n2 = 11. The hydroxyl equivalent of this hydroxy compound (Ph-2) calculated by GPC was 1447 g / equivalent.

[0389]

[0390] (Synthesis Example 3) A flask equipped with a thermometer, dropping funnel, condenser, and stirrer was charged with 198 g of the hydroxy compound (Ph-1) obtained in Synthesis Example 1, 435 g of epichlorohydrin, and 115 g of n-butanol, and dissolved while purging with nitrogen gas. After heating to 65°C, the pressure was reduced to an azeotropic pressure, and 6.6 g of a 49% aqueous sodium hydroxide solution was added dropwise over 5 hours. Stirring was then continued for 0.5 hours under the same conditions. During this time, the distillate distilled by azeotropy was separated using a Dean-Stark trap, the aqueous layer was removed, and the oil layer was returned to the reaction system while the reaction was continued. Unreacted epichlorohydrin was then distilled off by vacuum distillation. 150 g of methyl isobutyl ketone and 150 g of n-butanol were added to the crude epoxy resin obtained and dissolved. To this solution, 10 g of a 10% aqueous solution of sodium hydroxide was added, and the mixture was allowed to react at 80°C for 2 hours. The mixture was then washed three times with 50 g of water until the pH of the washings became neutral. The system was then dehydrated by azeotropy, and after microfiltration, the solvent was distilled off under reduced pressure to obtain the desired epoxy resin (Ep-1). The resulting epoxy resin (Ep-1) had an epoxy equivalent of 2308 g / equivalent, a viscosity at 60°C of 400,000 mPa·s, and a total chlorine content of 3.4%. Mass spectrometry of this epoxy resin (Ep-1) revealed a peak at M+ = 883, which corresponds to the theoretical structure of the following structural formula (Ep-1): m1 = 1, n1 = 12, p1 = 0, p2 = 0, and q = 1. This confirmed the presence of the desired epoxy resin (Ep-1).

[0391]

[0392] (Synthesis Example 4) In a flask equipped with a thermometer, dropping funnel, condenser, and stirrer, 156 g of the hydroxy compound (Ph-2) obtained in Synthesis Example 2, 644 g of epichlorohydrin, and 147 g of n-butanol were added and dissolved while purging with nitrogen gas. The mixture was then heated to 65°C, reduced pressure to an azeotropic pressure, and 10 g of 49% aqueous sodium hydroxide solution was added dropwise over 5 hours. Stirring was then continued under the same conditions for 0.5 hours. During this time, the distillate distilled by azeotropy was separated using a Dean-Stark trap, the aqueous layer was removed, and the oil layer was returned to the reaction system while the reaction was continued. Unreacted epichlorohydrin was then removed by vacuum distillation. 200 g of methyl isobutyl ketone and 100 g of n-butanol were added to the obtained crude epoxy resin and dissolved. To this solution, 15 g of a 10% aqueous solution of sodium hydroxide was added, and the mixture was allowed to react at 80°C for 2 hours. The mixture was then washed three times with 100 g of water until the pH of the washings became neutral. The system was then dehydrated by azeotropy, and after microfiltration, the solvent was distilled off under reduced pressure to obtain epoxy resin (Ep-2). The resulting epoxy resin (Ep-2) had an epoxy equivalent of 1820 g / equivalent, a viscosity at 60°C of 10,000 mPa·s, and a total chlorine content of 3.1%. Mass spectrometry of this epoxy resin (Ep-2) revealed a peak at M+ = 1336, which corresponds to the theoretical structure of the following structural formula (Ep-2): m = 1, n2 = 11, p1 = 0, p2 = 0, and q = 1. This confirmed the presence of the target epoxy resin (Ep-2).

[0393]

[0394] Synthesis Example 5 A flask equipped with a thermometer, a stirrer, and a condenser was charged with 1,6'-bismaleimide-(2,2,4-trimethyl)hexane (BMI-THM manufactured by Daiwa Chemical Industry Co., Ltd.), 30.8 g of furfuryl glycidyl ether (manufactured by Kanto Chemical Co., Ltd.), and 80 g of toluene. After purging with nitrogen, the mixture was reacted at 60°C for 12 hours. The toluene was then distilled off under reduced pressure to obtain 61 g of a glycidyl ether group-containing compound (D-1). A peak of M+=626 was observed in the mass spectrum of this glycidyl ether group-containing compound, confirming that it contained the target glycidyl ether group-containing compound (D-1). The epoxy equivalent was 331 g / equivalent.

[0395]

[0396] (Synthesis Example 6) The same reaction as in Synthesis Example 5 was carried out, except that 159.2 g of 1,6'-bismaleimide-(2,2,4-trimethyl)hexane (BMI-THM manufactured by Daiwa Chemical Industry Co., Ltd.) in Synthesis Example 5 was replaced with 179.2 g of 4,4'-diphenylmethane bismaleimide (BMI-THM manufactured by Daiwa Chemical Industry Co., Ltd.), to obtain 317 g of a glycidyl ether group-containing compound (D-2). Since a peak of M+=667 was obtained in the mass spectrum of this glycidyl ether group-containing compound, it was confirmed that it contained the target glycidyl ether group-containing compound (D-2). The epoxy equivalent was 351 g / equivalent.

[0397]

[0398] (Synthesis Example 7) The same reaction as in Synthesis Example 1 was carried out, except that 119.7 g (0.53 mol) of bisphenol A (hydroxyl equivalent 114 g / equivalent) in Synthesis Example 1 was replaced with 228.0 g (1.0 mol) of bisphenol A (hydroxyl equivalent 114 g / equivalent), to obtain 425 g of hydroxy compound (Ph-3). Mass spectrometry of this hydroxy compound (Ph-3) yielded a peak at M+ = 771, which corresponds to the theoretical structure of the following structural formula (Ph-3) in which m1 = 1 and n1 = 12, confirming that it contained the target hydroxy compound. The hydroxyl equivalent of this hydroxy compound (Ph-3) calculated by GPC was 330 g / equivalent.

[0399]

[0400] Synthesis Example 8: The same reaction as in Synthesis Example 3 was carried out, except that 198 g of the hydroxy compound (Ph-1) in Synthesis Example 3 was replaced with 310 g of the hydroxy compound (Ph-3), to obtain an epoxy resin (Ep-3). The obtained epoxy resin (Ep-3) had an epoxy equivalent of 425 g / equivalent, a viscosity at 60°C of 6000 mPa s, and a total chlorine content of 1.9%. Mass spectrometry of this epoxy resin (Ep-3) showed a peak at M+ = 883, which corresponds to the theoretical structure of the following structural formula (Ep-3) where m1 = 1, n1 = 12, p1 = 0, p2 = 0, and q = 1, confirming that it contained the target epoxy resin (Ep-3).

[0401]

[0402] <Preparation of Adhesive Body and Measurement of Initial Adhesion Strength> Each compound was used in the formulations shown in Tables 1 and 2 (the numbers in the tables are by mass) and mixed uniformly in a mixer (Thinky Corporation's "Awatori Rentaro ARV-200") to obtain a curable resin composition.

[0403] <Preparation of Cured Product> The resin composition was sandwiched between mirror-finished aluminum plates (JIS H 4000 A1050P, manufactured by Engineering Test Services Co., Ltd.) using a silicone tube as a spacer, and cured by heating under predetermined conditions to obtain a cured product with a thickness of 0.7 mm.

[0404] <Tensile elongation> The cured product was punched into a dumbbell shape (JIS K 7161-2-1BA) using a punching blade to prepare a test specimen. A tensile test of this test specimen was carried out in accordance with JIS K 7162-2 using a tensile tester (Shimadzu Corporation's "Autograph AG-IS") to evaluate the elongation at break in a measurement environment of 23°C (test speed: 2 mm / min).

[0405] <Observation of Phase Separation Structure> A cross section of the cured resin was prepared using an ultramicrotome, and the phase separation structure was observed. The observation was performed using a scanning electron microscope (SEM). The presence or absence of a phase separation structure in the cured product can be confirmed by SEM observation. When the cured product had a phase separation structure that formed a sea-island structure, the particle size of the island phases was measured. Note that the average particle size was determined by randomly selecting 50 island phases from the island phases within a 200 μm × 260 μm field of view, measuring the particle size, and then determining the average particle size. Furthermore, the relative hardness distribution of the sea phase and the island phases can be confirmed by AFM observation.

[0406]

[0407]

[0408] The formulations shown in the table are as follows: Ep-1: Epoxy resin obtained in Synthesis Example 3 Ep-2: Epoxy resin obtained in Synthesis Example 4 Ep-3: Epoxy resin obtained in Synthesis Example 8 E-850S: Bisphenol A liquid epoxy resin (DIC Corporation, epoxy equivalent 187 g / equivalent) SIZ: Imidazole (Shikoku Chemical Industry Co., Ltd.) 1-MZ: 1-methylimidazole (Tokyo Chemical Industry Co., Ltd.) F-190D, F-260D: Thermal expansion capsule (Matsumoto Yushi Pharmaceutical Co., Ltd.) GC160 50N: Expandable graphite (Graphtec International) D-1: Glycidyl ether group-containing compound obtained in Synthesis Example 5 D-2: Glycidyl ether group-containing compound obtained in Synthesis Example 6 DICY: Dicyandiamide (Mitsubishi Chemical Corporation, "DICY7") DTA: Diethylenetriamine (Kanto Chemical Co., Ltd.) DCMU: (3-(3,4-dichlorophenyl)-1,1-dimethylurea) (DIC Corporation, "B-605-IM")

[0409] <Preparation of Adhesion Samples> The resin composition was bonded to various substrates under the conditions shown in Tables 3 and 4. The resin composition was applied to one of the substrates (1.0 mm x 25 mm x 100 mm), glass beads ("J-80" manufactured by Potters Ballotini Co., Ltd.) were added as spacers, and the other substrate was bonded (adhesion area: 25 mm x 12.5 mm). This was cured at the temperatures shown in Tables 3 and 4 to obtain test specimens. The test specimens were subjected to a tensile shear test to evaluate adhesion. The test was performed in accordance with JIS K 6850, and the maximum point stress at a measurement environment of 23°C was compared.

[0410] "Initial adhesive strength": A shear test was carried out on the prepared test pieces without any particular treatment.

[0411] "Dismantleability during heating" The bonded structure was hung vertically, and a 500 g weight was applied to one side of the substrate. In this state, heating was performed using an induction heater and a dryer, and the adhesive state of the substrate was evaluated. The heating method and the criteria for dismantleability were as follows:

[0412] <Induction heating> An electromagnetic induction heater ("Solary" manufactured by Solary Electric Equipment Co., Ltd.) was used to heat the bonded body with a heating coil of 35 mm diameter (voltage 110 V, power consumption 1000 W). During heating, the substrate surface temperature was measured with a radiation thermometer, and heating was terminated when the substrate surface temperature reached 200°C. <Dryer heating> A precision incubator ("DH611S" manufactured by Yamato Scientific Co., Ltd.) was used, with the furnace temperature set to 200°C, and the bonded body was placed in it for 5 minutes to heat it.

[0413] <Evaluation criteria> A: The bonded portion shifted, and the bonded substrate on the side where the load was applied fell. B: The bonded portion shifted. C: No change occurred in the substrate.

[0414] "Time required for dismantling (time required for substrate to fall during heating)" The bonded structure was hung vertically, and a 500 g weight was applied to one side of the substrate. In this state, induction heating and a dryer were used to measure the time required for the substrate to fall under the load. The details of the heating method are as follows.

[0415] <Induction heating> Using an electromagnetic induction heater ("Solary" manufactured by Solary Electric Equipment Co., Ltd.), the bonded body was heated with a heating coil having a diameter of 35 mm (voltage 110 V, power consumption 1000 W). During heating, the surface temperature of the substrate was measured with a radiation thermometer, and the output was adjusted so that the surface temperature of the substrate did not exceed 200°C, and the time until the substrate fell was measured.

[0416] <Heating in a Dryer> Using a precision incubator (manufactured by Yamato Scientific, "DH611S"), the temperature inside the oven was set to 200°C, the bonded body was placed in, and the time required for the substrate to fall was measured.

[0417] <Evaluation criteria> A: The substrate fell within 1 minute B: The substrate fell between 1 and 10 minutes C: The substrate did not fall at the 10-minute mark

[0418] "Dismantling property after returning to room temperature" The bonded structure was hung vertically and subjected to induction heating and heating with a dryer without applying a load in the same manner as in the evaluation of "dismantling property during heating". After that, the substrate was returned to 23°C, and the shear adhesive strength was measured according to JIS K 6850. The adhesive state of the substrate was evaluated. The strength reduction rate was calculated using "(initial adhesive strength - adhesive strength after heating) / initial adhesive strength x 100" and evaluated according to the following criteria.

[0419] A: Strength reduction rate is 90% or more B: Strength reduction rate is 20% or more but less than 90% C: Strength reduction rate is less than 20%

[0420]

[0421]

[0422] The compositions shown in the table are as follows: SPCC-SD: cold-rolled steel plate (manufactured by TP Giken Co., Ltd.) A5052: aluminum plate (manufactured by Engineering Test Service Co., Ltd.) CFRP: epoxy resin matrix fiber reinforced plate (manufactured by Engineering Test Service Co., Ltd.)

[0423] As shown in the table, resins with a phase-separated structure possess excellent flexibility and initial adhesive strength, and additional heating by induction heating demonstrated dismantling properties. Furthermore, the developed product demonstrated dismantling properties not only during heating but also after heating. Comparative Examples 1 to 5, which use resin compositions that do not contain either epoxy resin (A) with an epoxy equivalent of 500 to 10,000 g / equivalent or epoxy resin (B) with an epoxy equivalent of 100 to 300 g / equivalent, demonstrated poor initial adhesive strength and poor dismantling properties. Comparative Example 6, while the adhesive layer has a phase-separated structure, required a long time for easy dismantling to occur when dismantled using a dryer, demonstrating issues with dismantling time during actual use. The results of Examples 1 to 14 and Comparative Examples 1 to 6 demonstrate that the combination of a phase-separated structure and induction heating results in high initial adhesive strength and easy dismantling properties. The phase separation structure developed in this study forms a sea-island structure with different elastic moduli, which allows for both flexibility and adhesive strength. It is also believed that the decrease in bulk elastic modulus during induction heating has a significant effect on the realization of dismantling functionality.

Claims

A method for dismantling a bonded structure in which a substrate A and a substrate B are bonded via an adhesive layer, comprising the steps of: the adhesive layer has a phase-separated structure, A method for dismantling a bonded body, comprising a heating step of inductively heating or microwave heating the bonded body. 　 the adhesive layer is a cured product of an epoxy resin composition, the phase-separated structure is generated by curing the epoxy resin composition, The epoxy resin composition comprises an epoxy resin (A) represented by the following general formula (1) and having an epoxy equivalent of 500 to 10,000 g / equivalent; The method for dismantling a bonded body according to claim 1, further comprising: (B) an epoxy resin having an epoxy equivalent of 100 to 300 g / equivalent. [In formula (1), each Ar independently represents a structure having an unsubstituted or substituted aromatic ring, X is a structural unit represented by the following general formula (2), and Y is a structural unit represented by the following general formula (3): [In formulas (2) and (3), Ar is the same as defined above, R １ , R ２ are each independently a hydrogen atom, a methyl group, or an ethyl group, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms; R ３ , R ４ , R ７ , R ８ each independently represents a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, R ５ , R ６ , R ９ , R １０ are each independently a hydrogen atom or a methyl group, n1 is an integer from 4 to 16, n2 is the average number of repeating units and is 2 to 30.] R １１ , R １２ are each independently a glycidyl ether group or a 2-methylglycidyl ether group, R １３ , R １４ each independently represents a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, R １５ , R １６ is a hydrogen atom or a methyl group, m1, m2, p1, p2, and q are the average values ​​of the repetitions, m1 and m2 each independently represent 0 to 25, and m1+m2≧1; p1 and p2 each independently represent 0 to 5; and q is 0.5 to 5. However, the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively. The method for dismantling an adhesive body according to claim 2, wherein the mass ratio (A):(B) of the epoxy resin (A) to the epoxy resin (B) is 90:10 to 10:

90. The method for dismantling a bonded structure according to claim 2 , wherein the epoxy resin composition further contains a heterocyclic aromatic compound (C) having a tertiary amino group.

5. The method for dismantling an adhesive-bonded structure according to claim 4, wherein the heterocyclic aromatic compound (C) having a tertiary amino group is at least one compound selected from the group consisting of imidazole compounds and pyridine compounds having a tertiary amino group. 　 The method for dismantling adhesive-bonded bodies according to claim 4, wherein the heterocyclic aromatic compound (C) having a tertiary amino group is at least one compound selected from the group consisting of imidazole, 1-methylimidazole, 2-ethyl-4-methylimidazole, and 4-dimethylaminopyridine.

5. The method for dismantling an adhesive-bonded body according to claim 4, wherein the heterocyclic aromatic compound (C) having a tertiary amino group is used in an amount of 2 to 20 parts by mass per 100 parts by mass of the epoxy resin (A) and the epoxy resin (B) combined. 　 The method for dismantling a bonded body according to any one of claims 2 to 4, wherein the epoxy resin composition further contains thermally expandable particles (D). 　 The method for dismantling a bonded body according to claim 8, wherein the thermally expandable particles (D) are at least one selected from the group consisting of thermally expandable microcapsules and expandable graphite.

9. The method for dismantling an adhesive body according to claim 8, wherein the use ratio of the thermally expandable particles (D) is within a range of 3 to 40 parts by mass per 100 parts by mass of the total of the epoxy resin (A) and the epoxy resin (B). 　 the epoxy resin composition further contains a glycidyl ether group-containing compound (E), The glycidyl ether group-containing compound (E) is a compound formed by connecting a structural unit V having one or more glycidyl ether groups and a structural unit W different from the structural unit V via V-W-V, 5. The method for dismantling an adhesive structure according to claim 2, wherein the structural unit V and the structural unit W are bonded to each other through a reversible bond formed by a Diels-Alder reaction between a furan structure and a maleimide structure. 　 the epoxy resin composition further contains a glycidyl ether group-containing compound (E), The glycidyl ether group-containing compound (E) is a compound formed by connecting a structural unit V having one or more glycidyl ether groups and a structural unit W different from the structural unit V via V-W-V, 9. The method for dismantling an adhesive structure according to claim 8, wherein the structural unit V and the structural unit W are bonded by a reversible bond due to a Diels-Alder reaction between a furan structure and a maleimide structure. The method for dismantling an adhesive-bonded structure according to claim 11, wherein the glycidyl ether group-containing compound (E) is a compound represented by the following general formula (4) and has a molecular weight of less than 1,000: [In formula (4), m3 is an integer of 1 to 4. Z １ is the following formula (5), Z ３ is any of the structures represented by the following formula (6), and a plurality of such structures in one molecule may be the same or different. [In formula (5), the aromatic ring may be unsubstituted or may have a substituent, * represents a bonding point, and G represents a glycidyl group or a 2-methylglycidyl group.] (In formula (6), each R″ is independently a hydrogen atom, a methyl group, or an ethyl group; w1 is an integer of 1 to 30; w2 is the average number of repeats and is 0.5 to 8; w3 is the average number of repeats and is 0.5 to 6; and * represents a bonding point.) The method for dismantling an adhesive-bonded body according to claim 12, wherein the glycidyl ether group-containing compound (E) is a compound represented by the following general formula (4) and has a molecular weight of less than 1,000: [In formula (4), m3 is an integer of 1 to 4. Z １ is the following formula (5), Z ３ is any of the structures represented by the following formula (6), and a plurality of such structures in one molecule may be the same or different. [In formula (5), the aromatic ring may be unsubstituted or may have a substituent, * represents a bonding point, and G represents a glycidyl group or a 2-methylglycidyl group.] (In formula (6), each R″ is independently a hydrogen atom, a methyl group, or an ethyl group; w1 is an integer of 1 to 30; w2 is the average number of repeats and is 0.5 to 8; w3 is the average number of repeats and is 0.5 to 6; and * represents a bonding point.) The method for dismantling an adhered body according to claim 2 , wherein the epoxy resin composition further contains a curing agent (F). 　 the phase-separated structure is composed of resin particles having an average particle size of 10 nm to 100 μm and a matrix surrounding the resin particles, 3. The method for dismantling an adhered body according to claim 2, wherein the resin particles contain a cured product of the epoxy resin (A), and the matrix contains a cured product of the epoxy resin (B). 　 the phase-separated structure is composed of resin particles having an average particle size of 10 nm to 100 μm and a matrix surrounding the resin particles, 3. The method for dismantling an adhered body according to claim 2, wherein the resin particles contain a cured product of the epoxy resin (B), and the matrix contains a cured product of the epoxy resin (A).

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