Method for dismantling adhesive structures

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

[Technical Field]

[0001] The present invention relates to a method for disassembling adhesive bodies. [Background technology]

[0002] Due to the increasing demand for lighter automobiles and aircraft to reduce CO2 emissions and improve fuel efficiency, weight reduction is progressing through measures such as reducing the number of spot welds and using fiber-reinforced resins and metals in combination. As a result, there is a strong need for high adhesive performance in the structural adhesives used in these materials.

[0003] On the other hand, achieving high adhesive performance can lead to the creation of products that are difficult to recycle, limiting their dismantling and reuse after use. Against the backdrop of growing environmental awareness, it is important to develop adhesives that maintain high adhesive performance while being easily removable after their lifespan.

[0004] Against this backdrop, the development of easily disassembled adhesives has been actively pursued. Generally, the thermal melting of thermoplastic resins is often utilized, but research into the combined use of thermosetting resins with thermally expanding materials is also being actively conducted. Furthermore, a temporary bonding method has been reported in which UV-curing adhesives for temporary fixing during the processing of optical glass, wafers, etc., are peeled off by microwave irradiation (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-120428 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, in conventional technologies such as the above-mentioned Patent Document 1, problems such as "the effect of thermal expansion cannot be obtained", "the adhesive is brittle and lacks flexibility", and "due to emphasizing flexibility, sufficient adhesive strength cannot be obtained" still remain. Also, as a problem in the disassembly operation, it is required to prevent the adhered material from being damaged and to minimize the impact of the disassembly process on the environment. An object of the present invention is to provide a method for disassembling an adhesive body that is excellent in adhesiveness, flexibility, and disassembly property.

Means for Solving the Problems

[0007] As a result of intensive studies, the inventors of the present invention have found that the above problems can be solved by using an adhesive having a phase separation structure and heating it by induction heating or microwave heating, and have completed the invention.

[0008] That is, the present invention includes the following aspects. 〔1〕 A method for disassembling an adhesive body in which a base material A and a base material B are joined via an adhesive layer, where the adhesive layer has a phase separation structure, and the method for disassembling the adhesive body includes a heating step of induction heating or microwave heating the adhesive body. 〔2〕 The method for disassembling an adhesive body according to 〔1〕, where the adhesive layer is a cured product of an epoxy resin composition, the phase separation structure is formed by curing the epoxy resin composition, and the epoxy resin composition contains an epoxy resin (A) having an epoxy equivalent of 500 to 10,000 g / equivalent represented by the following general formula (1) and an epoxy resin (B) having an epoxy equivalent of 100 to 300 g / equivalent.

[0009]

Chemical formula

[0010] [ka] [In equations (2) and (3), Ar is the same as described above, R1 and R2 are independently a hydrogen atom, a methyl group, or an ethyl group. R' is a divalent hydrocarbon group with 2 to 12 carbon atoms. R3, R4, R7, and R8 are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group. R5, R6, R9, R 10 Each of these is independently a hydrogen atom or a methyl group. n1 is an integer between 4 and 16. n² is the average value of the repetition unit, ranging from 2 to 30. R 11 , R 12 Each of these is independently a glycidyl ether group or a 2-methylglycidyl ether group. R 13 , R 14 Each of these is independently 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 repeated average values, m1 and m2 are independently between 0 and 25, and m1 + m2 ≥ 1. p1 and p2 are independently between 0 and 5. q is between 0.5 and 5. However, the bonding between X represented by general formula (2) and Y represented by general formula (3) may be random or blocky, and the total number of each structural unit X and Y present in one molecule is m1 and m2, respectively. [3] The method for dismantling an adhesive 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 an adhesive according to [2] or [3], wherein the epoxy resin composition further comprises a heterocyclic aromatic compound (C) having a tertiary amino group. [5] The method for dismantling an adhesive 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 an adhesive 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 an adhesive body according to any one of [4] to [6], wherein the proportion of the heterocyclic aromatic compound (C) having a tertiary amino group used is in the range of 2 to 20 parts by mass with respect to 100 parts by mass of the total of the epoxy resin (A) and the epoxy resin (B). [8] The method for dismantling an adhesive body according to any one of [2] to [7], wherein the epoxy resin composition further comprises thermally expandable particles (D). [9] The method for dismantling an adhesive body according to [8], wherein the thermally expandable particles (D) are at least one selected from the group consisting of thermally expandable microcapsules and expanded graphite.

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

[11] The epoxy resin composition further comprises a glycidyl ether group-containing compound (E), The glycidyl ether group-containing compound (E) is a compound in which a structural unit V having one or more glycidyl ether groups and a structural unit W different from the structural unit V are linked by VWV. A method for disassembling an adhesive body according to any one of [2] to

[10] , wherein the structural unit V and the structural unit W are bonded together by a reversible bond formed by a Diels-Alder reaction between a furan structure and a maleimide structure. The method for disassembling the adhesive 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 1000.

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

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

[0013] [Chemical formula] (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 an average value of the number of repetitions and is 0.5 to 8, w3 is an average value of the number of repetitions and is 0.5 to 6, and * represents a bonding point. ) ]

[13] The method for disassembling the adhesive according to any one of [2] to

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

[14] The phase separation structure consists of resin particles having an average particle diameter of 10 nm to 100 μm and a matrix surrounding the same, 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 disassembling the adhesive according to any one of [2] to

[13] .

[15] The phase separation structure consists of resin particles having an average particle diameter of 10 nm to 100 μm and a matrix surrounding the same, A method for disassembling 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). [Effects of the Invention]

[0014] According to the present invention, by using an adhesive having a phase-separated structure and heating it with induction heating or microwaves, a method for disassembling an adhesive body with excellent adhesion, flexibility, and disassembly properties can be provided. [Modes for carrying out the invention]

[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 carried out in various improved, modified, and altered forms based on the knowledge of those skilled in the art, without departing from the spirit of the invention, and all of these embodiments fall within the scope of the present invention. In this specification, numerical ranges indicated using "~" indicate a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. Also, unless specifically stated otherwise, the units of the numerical values ​​before and after "~" are the same. Furthermore, the upper and lower limits described individually can be combined in any way.

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

[0017] (induction heating) The induction heating used in the dismantling 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 a material. This causes the material (mainly conductive parts such as metals) to be Joule heated by the generation of eddy currents that oppose the change in magnetic flux. The higher the frequency of the alternating magnetic field, the easier it is for the surface of the material (adhesive interface) to heat 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 composed of a conductor, and it is desirable that the conductor be directly heated by electromagnetic induction. Depending on the shape and size of the adhesive, the specifications of the electromagnetic induction heating device, and the shape of its heating coil, the conductor constituting the adhesive interface should be heated by electromagnetic induction from a location and direction that is easy to work with.

[0019] Electromagnetic induction heating is best performed by applying an alternating magnetic field with a frequency higher than the typical frequency (5-30 kHz) (for example, 100-500 kHz or even around 300-400 kHz).

[0020] The frequency (f) of the alternating magnetic field is usually near the resonant (angular) frequency (f0) of the high-frequency power supply circuit. The high-frequency power supply circuit can be either a series resonant circuit or a parallel resonant circuit, but in either case, f0 = (LC) - 1 / 2 / 2π is desirable. 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 near the resonant frequency, the power supplied from the electromagnetic induction coil (simply called the "heating coil") is maximized. For this reason, the high-frequency power supply circuit should be configured such that the heating coil and the capacitors within the power supply circuit are selected or matched to obtain the desired resonant frequency. The frequency of the alternating magnetic field should ideally be within ±20%, or even ±10%, of the resonant frequency determined by the high-frequency power supply circuit (high-frequency power supply, coil, capacitor, resistor).

[0022] The conductor being heated by electromagnetic induction should ideally have high magnetic permeability and conductivity, and low thermal conductivity. This allows 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 conductive material constituting the adhesive interface is heated by electromagnetic induction, the conductive material is preferably a magnetic material, such as an iron substrate (pure iron, iron alloy, composite material, etc.). When the conductive material is a magnetic material (especially an iron substrate), the heating rate should be, for example, 16°C / second or higher, 18°C / second or higher, and even 20°C / second or higher. The heating rate (ΔT / t) is the average rate of change of temperature over time, obtained by dividing the time (t) required from the start of electromagnetic induction heating to the separation (peeling) of the adhesive interface by the temperature change (ΔT) on the first component (mainly the conductive material) side from the start to the separation (the same applies below).

[0024] Even if the conductor is a non-magnetic material, the adhesive can be disassembled using the processing method of the present invention. Non-magnetic materials include, for example, aluminum or copper substrates. Because such conductors have a large coefficient of thermal expansion, large thermal stress can be generated at the adhesive interface even without heating, unlike iron substrates. When the conductor is a non-magnetic material (especially an aluminum substrate), the heating rate should be 2°C / second or higher, 4°C / second or higher, or even 6°C / second or higher. Carbon substrates and fiber-reinforced polymers (CFRP) containing carbon fibers are also conductive, so heating by electromagnetic induction is possible. Furthermore, a magnetic material that is easily heated by electromagnetic induction may be placed near the conductor to assist in heating the conductor through heat 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 (substrate A, adhesive layer, substrate B). The content of the material capable of electromagnetic induction heating in any of the layers of the adhesive is not particularly limited as long as it is in an amount that can heat the adhesive layer. When using electromagnetic induction heating in the dismantling method of this embodiment, it is preferable that at least one layer of substrate A and substrate B is a conductor.

[0026] (Microwave heating) [Materials that can be heated by microwave] The microwave heating used in the dismantling method of this embodiment preferably uses electromagnetic waves in the range of 300 MHz to 300 GHz. This microwave heating method heats an object to be heated by generating heat through molecular motion and ion conduction caused by the action of electromagnetic waves in the range of 300 MHz to 300 GHz. Therefore, it is possible to heat dielectrics, conductors, and magnetic materials, but it is mainly suitable for heating dielectrics. Examples of dielectrics include various synthetic resins, ceramics such as silicon carbide and silicon nitride, and mica. Examples of conductors include metallic materials and conductive nonmetallic materials similar to those that can be heated by electromagnetic induction. Examples of magnetic materials 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 (substrate A, adhesive layer, substrate B). The content of the microwave-heatable material in any of the layers of the adhesive is not particularly limited as long as it is in an amount that can heat the adhesive layer. When microwave heating is used in the dismantling method of this embodiment, it is preferable, and more preferable, that at least one of the substrate A, adhesive layer, and substrate B contains a dielectric.

[0028] (adhesive) The adhesive body comprises the base material A, the base material B, and the adhesive layer, wherein the base material A and the base material B are bonded together via the adhesive layer.

[0029] The materials of the substrates A and B used as the adherends are not particularly limited and include, for example, inorganic materials such as metals and glass, organic materials such as plastics and wood, and fiber-reinforced resins such as CFRP, CFRTP, GFRP, and GFRTP. These materials may be used as appropriate depending on the application.

[0030] The base material A and the base material B may be the same material or different materials. Since the adhesive layer can relieve stress, it is preferable in some applications for base materials A and B to be made of different materials. For example, even if the base material is a metal and / or metal oxide and the second base material is a plastic layer, the adhesive strength is maintained due to the stress-relieving 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. Examples of the metal oxide include individual oxides and / or composite oxides of these metals. Iron, copper, and aluminum are preferred as the metal because they exhibit excellent adhesion to the adhesive layer, especially to iron, copper, and aluminum.

[0032] The shapes of base material A and base material B may be any shape depending on the purpose. For example, they may be flat plates, sheets, or have a three-dimensional structure. They may also have curvature on all or part of their surface. The shapes of base material A and base material B may be any shape depending on the purpose.

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

[0034] <Method for forming an adhesive> In the adhesive according to this embodiment, the adhesive can be any adhesive that exhibits a phase separation structure, and for example, a crosslinkable composition described in Japanese Patent No. 7435920 can be used. Among these, it is preferable to use an epoxy resin composition, which will be described later. The adhesive layer may be formed on the substrate A (or substrate B) by direct coating or molding, or a pre-molded layer may be laminated. When direct coating is performed, there are no particular limitations on the coating method, and examples include spraying, spin coating, dipping, roll coating, blade coating, doctor roll, doctor blade, curtain coating, slit coating, screen printing, and inkjet. When direct molding is performed, examples include in-mold molding, insert molding, vacuum molding, extrusion lamination, 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 fully cured 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 its cured product 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) with an epoxy equivalent of 500 to 10,000 g / equivalent, an epoxy resin (B) with an epoxy equivalent of 100 to 300 g / equivalent, a heterocyclic aromatic compound (C) having a tertiary amino group if necessary, 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 in which a structural unit V having one or more glycidyl ether groups and a structural unit W different from the structural unit V are linked by VWV. The structural unit V and the structural unit W are linked by 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 other epoxy resins other than the epoxy resin (A), epoxy resin (B), and 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, non-halogenated flame retardants, fillers not belonging to the thermally expandable particles (D) according to this embodiment, or dispersion media. Furthermore, 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 way as the total chlorine content of epoxy resin (A) described later. For example, the measurement method described in the examples described later can be cited. The following provides a detailed explanation of each component.

[0039] [Epoxy resin (A)]

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

[0041] [ka] [In formula (1), each Ar independently has a structure that is either unsubstituted or has a 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).

[0042] [ka]

[0043] [In equations (2) and (3), Ar is the same as described above, R1 and R2 are independently a hydrogen atom, a methyl group, or an ethyl group. R' is a divalent hydrocarbon group with 2 to 12 carbon atoms. R3, R4, R7, and R8 are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group. R5, R6, R9, R 10 Each of these is independently a hydrogen atom or a methyl group. n1 is an integer between 4 and 16. n² is the average value of the repetition unit, ranging from 2 to 30. R 11 , R 12 Each of these is independently a glycidyl ether group or a 2-methylglycidyl ether group. R 13 , R 14 Each of these is independently 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 repeated average values, m1 and m2 are independently between 0 and 25, and m1 + m2 ≥ 1. p1 and p2 are independently between 0 and 5. q is between 0.5 and 5. However, the bonding between X represented by general formula (2) and Y represented by general formula (3) may be random or blocky, and the total number of each structural unit X and Y present in one molecule is m1 and m2, respectively.

[0044] The above structure contains structural unit X represented by general formula (2) and / or structural unit Y represented by general formula (3). The presence of alkylene chains or polyether chains in each structural unit makes it possible to exhibit high flexibility in the cured product. In particular, the flexibility derived from alkylene chains can follow the thermal expansion of the substrate when it is cured as an epoxy, and the polyether chains contribute to improving the processability and coating properties of the epoxy resin composition by reducing the viscosity of the epoxy resin (A) itself.

[0045] In the epoxy resin (A) described above, structural units X and Y may exist individually, or both structural units X and Y may be present 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 structural units X and Y contained in one molecule is m1 and m2, respectively.

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

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

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

[0049] Furthermore, structures represented by the following formula can also be considered as Ar.

[0050] [ka] (In the formula, the aromatic ring may be unsubstituted or substituted, n3 = 1 to 4, and * represents a bond point.)

[0051] The aromatic ring of Ar may be unsubstituted or substituted. If Ar is substituted, preferred substituents include alkyl groups, halogen atoms, glycidyl ether groups, and 2-methylglycidyl ether groups. Preferably, it is unsubstituted, or alkyl groups, glycidyl ether groups, or 2-methylglycidyl ether groups. It is preferable that there are two or fewer substituents per aromatic ring, more preferably one or fewer, and particularly preferable that it be unsubstituted.

[0052] The following structures of Ar are particularly preferred. * indicates a bond point.

[0053] [ka]

[0054] Particularly preferred structures for substituted Ar include the following structures. * represents a bond point.

[0055] [ka]

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

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

[0058] Among these, R3 and R4 are preferably hydroxyl groups, and R5 and R6 are preferably hydrogen atoms.

[0059] In the structural unit Y represented by the general formula (3) above, n2 is the average value of the repeating units and is between 2 and 30. This range is preferable because it provides a good balance between the viscosity of the epoxy resin (A) and the crosslinking density of the resulting cured product. More preferably, n2 is between 2 and 25, and even more preferably between 4 and 20.

[0060] In the structural unit Y represented by the general formula (3) above, 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 deformation. It is preferable that R' is a divalent hydrocarbon group having 2 to 6 carbon atoms.

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

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

[0063] Among these, ethylene groups, propylene groups, and tetramethylene groups are preferred from the viewpoint of ease of obtaining 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) above, R7 and R8 are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R9 and R 10 Each of these is independently a hydrogen atom or a methyl group. R7 and R8 are preferably hydroxyl groups, and R9 and R 10 It is preferable that it is 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 structural units X and Y, respectively, and are independently between 0 and 25, and m1 + m2 ≥ 1.

[0066] Furthermore, R in the general formula (1) 11 , R 12 Each of these is independently a glycidyl ether group or a 2-methylglycidyl ether group, R 13 , R 14 Each of these is independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R 15 , R 16 Each of these is independently a hydrogen atom or a methyl group, and p1, p2, and q are the average values ​​of the repeats, with p1 and p2 independently ranging from 0 to 5, and q ranging from 0.5 to 5. Among these, R 11 , R 12 It is preferable that R is a glycidyl ether group. 13 , R 14 It is preferably a hydroxyl group, R 15 , R 16 It is preferable that the atom is a hydrogen atom. Furthermore, it is preferable that p1 and p2 are 0 to 2, and that q is 0.5 to 2.

[0067] Furthermore, the epoxy equivalent weight of the epoxy resin (A) used in this embodiment is 500 to 10,000 g / equivalent. Within this range, the resulting cured product exhibits excellent adhesion, flexibility, and decomposability. From the viewpoint of ease of handling, it is preferable that the epoxy equivalent weight be 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) in this embodiment, a resin having both structural unit X and structural unit Y in a single molecule can be given, for example, the resin with the following structural formula. In the structural formula described in two lines, * represents a bond point.

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

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

[0082] Among the structural formulas described above, it is preferable to use those represented by structural formulas (A-1), (A-2), (A-3), (A-5), (A-7), (A-8), and (A-9) from the viewpoint of having excellent adhesion, flexibility, and decomposability of the resulting epoxy resin cured product.

[0083] Among the epoxy resins (A) mentioned above, an example of an epoxy resin having the aforementioned structural unit X is a resin represented by the following structural formula.

[0084] [ka]

[0085] [ka]

[0086] [ka]

[0087] [ka]

[0088] [ka]

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] [ka]

[0093] [ka]

[0094] [ka]

[0095] [ka]

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

[0097] Among the structural formulas described above, it is preferable to use those represented by structural formulas (A-13), (A-14), (A-15), (A-17), (A-19), (A-20), and (A-21) because they offer excellent adhesion, flexibility, and decomposability of the resulting epoxy resin cured product.

[0098] Among the epoxy resins (A) mentioned above, an example of an epoxy resin having the aforementioned structural unit Y is a resin represented by the following structural formula.

[0099] [ka]

[0100] [ka]

[0101] [ka]

[0102]

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[0103]

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[0104]

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[0105]

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[0106]

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[0107]

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[0109]

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[0110]

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[0111] In the above 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 between 2 and 30, m21, p11, p21, and q11 are the average values ​​of the repeats, m21 is between 0.5 and 25, p11 and p21 are independently between 0 and 5, and q11 is between 0.5 and 5. However, each repeating unit within a repeating unit may be the same or different.

[0112] Among the structural formulas described above, it is preferable to use those represented by structural formulas (A-25), (A-26), (A-27), (A-29), (A-31), (A-32), and (A-33) because they offer excellent adhesion, flexibility, and decomposability of the resulting epoxy resin cured product.

[0113] <Method for manufacturing 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 of a dihydroxy compound having an alkylene chain and / or a polyether chain (a1), an aromatic hydroxy compound (a2), and an epihalohydrin (a3) ​​is preferred because the raw materials are readily available and the reaction is easy. The epoxy resin may be produced by reacting all of the reaction raw materials at once, or by reacting the reaction raw materials sequentially. The method of reacting the reaction raw materials sequentially is preferred because the resulting epoxy resin cured product has excellent adhesion, flexibility, and decomposability.

[0114] One method for sequentially reacting the aforementioned reaction materials is to react a diglycidyl etherified product (a1) of a dihydroxy compound having an alkylene chain and a polyether chain with an aromatic hydroxy compound (a2) in a molar ratio (a1) / (a2) within the range of 1 / 1.01 to 1 / 5.0 to obtain a hydroxy compound (a12) [corresponding to a precursor or intermediate of epoxy resin (A)], and then react it with an epihalohydrin (a3). The "molar ratio (a1) / (a2)" is the molar ratio of the epoxy group of the diglycidyl etherified product (a1) to the phenolic hydroxyl group (hydroxyl group bonded to an aromatic ring) of the aromatic hydroxy compound (a2).

[0115] Furthermore, in terms of excellent adhesion, flexibility, and decomposability 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 method described in the examples below.

[0116] The product obtained by the reaction of the diglycidyl etherified product (a1) of the dihydroxy compound having the alkylene chain and polyether chain with the aromatic hydroxy compound (a2) may contain unreacted aromatic hydroxy compound (a2). However, in the synthesis of the epoxy resin (A) used in this embodiment, it may be subjected to the reaction with the epihalohydrin (a3) ​​in the next step as is, or the unreacted aromatic hydroxy compound (a2) may be removed. However, from the viewpoint of balancing the toughness and flexibility of the cured product obtained from the epoxy resin composition according to this embodiment, which includes the resulting epoxy resin (A), it is preferable that the proportion of unreacted aromatic hydroxy compound (a2) in the hydroxy compound subjected to the next step is in 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 using differences in polarity, distillation fractionation using differences in boiling points, and alkaline aqueous extraction using differences in solubility in alkaline water are examples. Among these, alkaline aqueous extraction is preferred in terms of yield, etc., because it does not involve thermal degradation. In this case, the organic solvent used to dissolve the target product is preferably one that does not mix with water, such as toluene, methyl isobutyl ketone, or butyl acetate, and methyl isobutyl ketone is particularly preferred from the viewpoint of solubility with the target product.

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

[0119] Examples of diglycidyl ethers (a1) of dihydroxy compounds having alkylene chains and polyether chains include 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, and 1,13- Examples include lidecanediol diglycidyl ether, 1,14-tetradecanediol diglycidyl ether, 1,15-pentadecanediol diglycidyl ether, 1,16-hexadecanediol diglycidyl ether, 2-methyl-1,11-undecanediol diglycidyl ether, 3-methyl-1,11-undecanediol diglycidyl ether, and 2,6,10-trimethyl-1,11-undecanediol diglycidyl ether. Examples of diglycidyl ethers 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 organochlorine impurities generated during the glycidyl etherification of hydroxy compounds, and may contain organochlorine such as 1-chloromethyl-2-glycidyl ether (chloromethyl derivative) represented by the structure shown below. These diglycidyl ethers may be used alone or in combination of two or more types. The total chlorine content in the diglycidyl etherified product (a1) of the dihydroxy compound having the alkylene chain and 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] [ka]

[0121] Among the above specific examples of diglycidyl ethers (a1) of dihydroxy compounds having alkylene chains and polyether chains, it is preferable to use 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, in order to obtain a cured product with excellent adhesion, flexibility, and decomposition properties.

[0122] Furthermore, by simultaneously reacting the aforementioned 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 structural unit X and structural unit Y is obtained. By further reacting this with the epihalohydrin (a3), an epoxy resin (A) having both structural unit X and structural unit Y is obtained.

[0123] The aromatic hydroxy compound (a2) is not particularly limited as long as it contains two or more phenolic hydroxyl groups, for example: 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; and 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 obtained by coupling reactions of dihydroxynaphthalenes, such as 1,1'-methylenebisu(2,7-naphthalenediol), 1,1'-binaphthalene-2,2',7,7'-tetraol, and 1,1'-oxybisu(2,7-naphthalenediol); bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, and 2,2-bis(3-methyl-4-hydro Bisphenols such as xyphenyl)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 ,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 polyadditives of phenol and dicyclopentadiene, and polyadditives of phenol and terpene compounds; naphthols such as bis(2-hydroxy-1-naphthyl)methane and bis(2-hydroxy-1-naphthyl)propane;Examples of polyhydric phenolic compounds include so-called Zyloc-type phenolic resins, which are condensation reaction products of phenol and phenylene dimethyl chloride or biphenylene dimethyl chloride; phenol novolac resins, cresol novolac resins, dicyclopentadienephenol addition resins, phenol aralkyl resins (Zyloc resins), naphthol aralkyl resins, trimethylol methane resins, tetraphenylolethane resins, naphthol novolac resins, naphthol-phenol co-condensed novolac resins, naphthol-cresol co-condensed novolac resins, biphenyl-modified phenolic resins (polyhydric phenolic compounds in which the phenol nucleus is linked by a bismethylene group), biphenyl-modified naphthol resins (polyhydric naphthol compounds in which the phenol nucleus is linked by a bismethylene group), aminotriazine-modified phenolic resins (polyhydric phenolic compounds in which the phenol nucleus is linked by melamine, benzoguanamine, etc.), and alkoxy-group-containing aromatic ring-modified novolac resins (polyhydric phenolic compounds in which the phenol nucleus and alkoxy-group-containing aromatic ring are linked by formaldehyde). These compounds may be used individually or in combination of two or more. Furthermore, compounds in which a methyl group, a t-butyl group, or a halogen atom is substituted as a substituent on the aromatic ring of each of the above compounds are also included. Note that the alicyclic structure-containing phenols and the Zylok-type phenol resins may contain not only difunctional components but also trifunctional or higher components simultaneously. In this invention, they may be used as is, or they may be used after purification using a column or other process to isolate only the difunctional components.

[0124] Among these, bisphenols are preferred due to their excellent adhesion, flexibility, and decomposability of the resulting epoxy resin cured product, and bis(4-hydroxyphenyl)methane and 2,2-bis(4-hydroxyphenyl)propane are particularly preferred due to their remarkable toughness-imparting properties. Furthermore, when the curability and heat resistance of the resulting epoxy resin cured product are important, dihydroxynaphthalenes are preferred, and 2,7-dihydroxynaphthalene is particularly preferred due to its remarkable rapid curing properties. Furthermore, when the moisture resistance of the resulting epoxy resin cured product is important, it is preferable to use compounds containing an alicyclic structure.

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

[0126] "A catalyst used in the reaction between (a1) and (a2)" The reaction between the diglycidyl etherified product (a1) of the dihydroxy compound having the alkylene chain and polyether chain and the aromatic hydroxy compound (a2) 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; 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) and 4-dimethylaminopyridine (DMAP); chlorides, bromides, and iodides such as 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 can be used individually 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 rapidly and have a high effect in reducing the amount of impurities in the 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 may be used in aqueous solution form or in solid form.

[0127] "The solvent used in the reaction between (a1) and (a2)" Furthermore, the reaction between the diglycidyl etherified product (a1) of the dihydroxy compound having the alkylene chain and polyether chain and the aromatic hydroxy compound (a2) can be carried out without a solvent or in the presence of an organic solvent. Examples of organic solvents that can be used include alcohol-based solvents, glycol-based solvents, hydrocarbon-based solvents, ester-based solvents, ketone-based solvents, ether-based solvents, and dimethyl sulfoxide. Examples of alcohol-based solvents 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 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 50 to 300% by mass, and more preferably 100 to 250% by mass, relative to the total mass of the raw materials. The organic solvent may be used alone or in combination of two or more types. Solvent-free is preferred for rapid reaction, while dimethyl sulfoxide is preferred in terms of reducing impurities in the final product.

[0129] "Reaction conditions for (a1) and (a2)" The reaction temperature when (a1) and (a2) are carried out is usually 50 to 180°C, and the reaction time is usually 1 to 30 hours. A reaction temperature of 100 to 160°C is preferred in that it can reduce impurities in the final product. If the resulting compound is highly discolored, antioxidants or reducing agents may be added to suppress this discoloration. Antioxidants are not particularly limited, but examples include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite ester compounds containing trivalent phosphorus atoms. Reducing agents are not particularly limited, but examples include hypophosphorous acid, phosphite, thiosulfite, sulfite, hydrosulfite, or salts thereof.

[0130] After the reaction between (a1) and (a2) is complete, the reaction mixture may be neutralized or washed with water until its pH is 3 to 7, preferably 5 to 7. Neutralization and washing can be carried out according to conventional methods. For example, when a basic catalyst is used, acidic substances such as hydrochloric acid, sodium dihydrogen phosphate, p-toluenesulfonic acid, or oxalic acid can be used as neutralizing agents. After neutralization or washing with water, the solvent may be removed under reduced pressure and heating to concentrate the product and obtain the hydroxy compound.

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

[0132] [ka]

[0133]

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[0134]

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[0135]

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[0136]

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[0137]

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[0138]

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[0139]

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[0140]

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[0141]

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[0142]

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[0143] [ka]

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

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

[0146] [ka]

[0147] [ka]

[0148] [ka]

[0149] [ka]

[0150] [ka]

[0151] [ka]

[0152] [Chemistry]

[0153] [Chemistry]

[0154] [Chemistry]

[0155] [Chemistry]

[0156] [Chemistry]

[0157] [Chemistry]

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

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

[0160] [Chemistry]

[0161] [Chemistry]

[0162] [Chemistry]

[0163]

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[0164]

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[0165]

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[0166]

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[0167]

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[0168]

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[0169]

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[0170]

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[0171]

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

[0173] In the method for producing the epoxy resin (A), there are no particular limitations on the method for the glycidyl etherification reaction of the precursor (intermediate) hydroxy compound (a12) obtained above. Examples include reacting a phenolic hydroxyl group with an epihalohydrin (a3), or olefinizing the phenolic hydroxyl group and oxidizing the carbon-carbon double bond of the olefin with an oxidizing agent. Among these, the method using epihalohydrin (a3) ​​is preferred because the raw materials are readily available and the reaction is easy.

[0174] One method using the epihalohydrin (a3) ​​is to add 0.3 to 100 moles of the epihalohydrin (a3) ​​to 1 mole of the phenolic hydroxyl groups of the hydroxy compound (a12) obtained above, and then react the mixture at a temperature of 20 to 120°C for 0.5 to 10 hours while adding 0.9 to 2 moles of basic catalyst per mole of phenolic hydroxyl groups of the hydroxy compound all at once or gradually. The more the amount of epihalohydrin (a3) ​​added is in excess of the phenolic hydroxyl groups, the closer the resulting epoxy resin will be to the theoretical structure, and the formation of secondary hydroxyl groups generated by the reaction between unreacted phenolic hydroxyl groups and epoxy groups can be suppressed. From this viewpoint, it is preferable that the equivalent amount of epihalohydrin (a3) ​​added relative to the phenolic hydroxyl groups of the hydroxy compound is in the range of 2.5 to 100 equivalents. This basic catalyst may be used in solid form or as an aqueous solution. When using an aqueous solution, it may be added continuously, and water and epihalohydrin (a3) ​​may be continuously distilled from the reaction mixture under reduced pressure or atmospheric pressure, followed by liquid-liquid separation to remove the water and continuously returning the epihalohydrin (a3) ​​to the reaction mixture.

[0175] When carrying out industrial production, it is preferable to use all new epihalohydrin (a3) ​​in the first batch of epoxy resin production, but in subsequent batches, it is preferable to use a combination of epihalohydrin (a3) ​​recovered from the crude reaction product and new epihalohydrin (a3) ​​equivalent to the amount consumed and lost in the reaction. At this time, the epihalohydrin (a3) ​​used is not particularly limited, but examples include epichlorohydrin and epibromohydrin. Among these, epichlorohydrin is preferred because it is readily available.

[0176] "A catalyst used in the reaction between precursors (a12) and (a3)." In the method for producing the epoxy resin (A), the catalyst used in the reaction between the precursor (intermediate) hydroxy compound (a12) obtained above and (a3) ​​is the catalyst described above in "Catalyst used in the reaction between (a1) and (a2)".

[0177] "The solvent used in the reaction between precursors (a12) and (a3)" In the method for producing the epoxy resin (A), the reaction of the precursor (intermediate) hydroxy compound (a12) obtained above with (a3) ​​can be carried out without a solvent or in the presence of an organic solvent. Examples of organic solvents that can be used are those described above in "Solvents used in the reaction between (a1) and (a2)".

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

[0179] When using the aforementioned phase transfer catalyst, the amount used is preferably in the range of 0.1 to 3% by mass relative to the solid content of the reaction product. After the reaction is complete, the generated salt is removed by filtration, washing with water, etc., and then solvents such as toluene and methyl isobutyl ketone are removed by distillation under reduced pressure and heating to obtain a high-purity epoxy resin.

[0180] [Epoxy resin (B)]

[0181] The epoxy resin (B) may have an epoxy equivalent weight in the range of 100 to 300 g / equivalent, and its structure is not limited. For example, liquid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD ​​type epoxy resin, polyhydroxybenzene type epoxy resin, polyhydroxynaphthalene type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, brominated epoxy resins such as brominated phenol novolac type epoxy resin, solid bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenylmethane type epoxy resin, tetraphenyl Examples include ruethane-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 copolymer novolac type epoxy resins, naphthol-cresol copolymer novolac type epoxy resins, and biphenyl-modified novolac type epoxy resins. These can be used individually or in combination of two or more types, and it is preferable to select and use them according to the intended application and the physical properties of the cured product.

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

[0183] Furthermore, in terms of excellent adhesion, flexibility, and decomposability of the resulting epoxy resin cured product, the viscosity of the epoxy resin (B) at 25°C is preferably 500 mPa·s to 30000 mPa·s, more preferably 700 mPa·s to 25000 mPa·s, and even more preferably 1000 mPa·s to 20000 mPa·s. The total chlorine content is preferably 0.001 to 20% by mass, more preferably 0.001 to 15% by mass, even more preferably 0.01 to 10% by mass, and even more preferably 0.01 to 5% by mass.

[0184] In this embodiment, there are no particular limitations on the ratio of epoxy resin (A) to epoxy resin (B) used. However, from the viewpoint of easily forming a phase separation structure in the cured product when the epoxy resin composition is cured, the mass ratio (A):(B) of epoxy resin (A) to 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 to 60. Phase separation occurs in the cured product, forming a sea-island structure, which allows for both adhesion and stress relaxation of the cured product, resulting in high adhesive strength over a wide temperature range and reducing the molding shrinkage rate of the resin composition before and after heat curing.

[0185] The phase separation structure is formed spontaneously during the curing reaction based on the compatibility of epoxy resin (A) and epoxy resin (B), and generally consists of island phases of resin particles with an average particle size of 10 nm to 100 μm and a matrix (sea phase) surrounding them. At this time, whether the cured product forming the resin particles and the cured product forming the matrix are cured products of epoxy resins is determined by their mixing ratio, the type of curing agent, or the conditions of their effects. In other words, the resin particles may contain cured product of epoxy resin (A) and the matrix may contain cured product of epoxy resin (B), or both cases may be possible.

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

[0187] [Heterocyclic aromatic compounds having a tertiary amino group (C)] The heterocyclic aromatic compound (C) having a tertiary amino group (hereinafter sometimes simply referred to as "compound (C)") that may be optionally included in the epoxy resin composition according to this embodiment is not particularly limited and only needs to have a tertiary amino group and an aromatic heterocycle (a heterocycle having aromatic properties) in its molecule. If the aromatic heterocycle itself has a tertiary amino group, only that aromatic heterocycle needs to be included. The heterocyclic aromatic compound (C) having a tertiary amino group can also be called an aromatic heterocyclic compound (C) having a tertiary amino group.

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

[0189] Examples of the imidazole compounds include substituted or unsubstituted imidazoles. Specific examples of the imidazole compounds include, for example, 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. L, 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 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 isocyanurate adduct, 2-methylimidazole isocyanurate 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) are preferred.

[0190] Examples of the imidazoline compounds include substituted or unsubstituted imidazolines. Specific examples of the imidazoline compounds include, for example, 2-methylimidazoline, 2-ethylimidazoline, 2-phenylimidazoline, and 2-benzylimidazoline.

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

[0192] The proportion of compound (C) used is preferably in the range of 2 to 20 parts by mass, more preferably in the range of 3 to 15 parts by mass, and even more preferably in the range of 5 to 12 parts by mass, per 100 parts by mass of the total of epoxy resin (A) and epoxy resin (B), from the viewpoint of exhibiting the effect of sufficiently expanding and reducing adhesion during disassembly after use without impairing the adhesion 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 in combination with a curing agent as a curing accelerator in the curing of epoxy resins, 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] [Thermally expandable particles (D)] The thermally expandable particles (D) optionally included in the epoxy resin composition according to this embodiment may be made of an inorganic material or an organic material. Examples of the material include expandable graphite provided in Japanese Patent Application Publication No. 2000-44219, etc. Examples of the organic material include thermally expandable microcapsules that use a thermoplastic polymer as an outer shell and microencapsulate a volatile expanding agent that becomes gaseous at temperatures below its softening point.

[0195] Among these, it is preferable to use thermally expandable microcapsules made of the aforementioned organic material because they exhibit uniform dispersion when used in epoxy resin compositions and have excellent electrical insulation properties as the resulting epoxy resin cured product.

[0196] Furthermore, among these, it is preferable to use the aforementioned expandable graphite because of its heat resistance and durability as an expandable particle, its excellent conductivity as an epoxy resin cured product, and the fact that the expandable particles themselves can be heated by induction heating or microwaves.

[0197] "Thermally expandable microcapsules" A method for manufacturing the aforementioned heat-expandable microcapsules was provided in the past in Japanese Patent Publication No. 42-26524, but from the viewpoint of heat-curing the epoxy resin in this embodiment, it is preferable that the method has heat resistance. A method for manufacturing the aforementioned heat-resistant heat-expandable microcapsules is provided in, for example, WO99 / 46320, WO99 / 43758, Japanese Patent Application Publication No. 2002-226620, etc.

[0198] In other words, it is preferable that the particles maintain their original shape without thermal expansion during the heat curing of the epoxy resin, and then expand due to higher temperature thermal energy after use. For example, it is preferable that the outer shell polymer is a polymer obtained by polymerizing a nitrile monomer and a monomer having a carboxyl group as essential components.

[0199] To further enhance heat resistance, it is also preferable to use monomers having an amide group or monomers having a cyclic structure in their side chains.

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

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

[0202] Furthermore, fluorine-based compounds such as hydrochlorofluorocarbons, hydrofluorocarbons, and hydrofluoroethers; commonly known as CFCs, fluorocarbons, and fluoroethers are also cited as examples, but their use should be avoided in the current social climate due to concerns about ozone layer depletion and global warming. In actual production, the general manufacturing methods for conventional thermally expandable microcapsules are used. Specifically, inorganic fine particles such as silica, magnesium hydroxide, calcium phosphate, and aluminum hydroxide are used as dispersion stabilizers in aqueous systems. In addition, condensation products of diethanolamine and aliphatic dicarboxylic acids, polyvinylpyrrolidone, methylcellulose, polyethylene oxide, polyvinyl alcohol, and various emulsifiers are used as dispersion stabilization aids.

[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. A method for measuring the average particle size of the thermally expandable microcapsules is, for example, measurement of the volume-average particle diameter using a particle size distribution analyzer (LA-950, manufactured by HORIBA Corporation).

[0204] "Expanded graphite" The method for producing the aforementioned expanded graphite is provided, for example, in Japanese Patent Publication No. 2000-44219, but from the viewpoint of thermosetting the epoxy resin in this embodiment, it is preferable that the expanded graphite has heat resistance. The method for producing the aforementioned heat-resistant expanded graphite is provided, for example, in Japanese Patent Publication No. 2012-193053.

[0205] The expanded graphite can usually be obtained by treating graphite such as natural graphite, pyrolysis graphite, or quiche graphite with a mixture of concentrated sulfuric acid and a strong oxidizing agent (hereinafter referred to as acid treatment) to generate interlayer compounds between the graphite layers, followed by washing with water, filtering, and drying. The acid treatment method is generally based on concentrated sulfuric acid, 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. A method using only fuming nitric acid is also known. A neutralization step with a base may be added after the acid treatment. The pH of the extract water of expanded graphite is preferably 5 to 9, more preferably 6 to 8. Furthermore, the pH of the extract water when 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 aforementioned expanded graphite is selected based on the range of the longest diameter of the particles. For this reason, commercially available expanded graphite is expressed in terms of particle size rather than by its longest diameter. Specifically, commercially available expanded graphite is classified using a sieve, and its characteristics are displayed by indicating the mesh size and pass percentage of the sieve.

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

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

[0209] The aforementioned thermally expandable particles (D) can also be commercially available. Examples of commercially available products include: Expandable capsules manufactured by Nippon Philite Co., Ltd. (product name: ExpanseL®), Expandable capsules manufactured by Sekisui Chemical Co., Ltd. (product name: Advancel EM), Microspheres manufactured by Matsumoto Oil & Fat Pharmaceutical Co., Ltd. (product 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 (product names: H850D, H880D, S2340D, S2 Examples include 640D), expanded graphite manufactured by Fuji Graphite Industry Co., Ltd. (product names: EXP-50S120K, EXP-50S150), expanded graphite manufactured by Ito Graphite Industry Co., Ltd. (product names: 953240L, 9550250), expanded graphite manufactured by Air Water Inc. (product names: 50LTE-U, MZ-260, CA-60, SS-3, SS-3LA), and expanded graphite manufactured by Graphtec International Corporation (product name: GRAFGUARD®). It is preferable to appropriately select particles that do not expand at the curing temperature of the epoxy resin composition but expand at the heating temperature during dismantling.

[0210] The proportion of the thermally expandable particles (D) used is preferably in the range of 3 to 40 parts by mass per 100 parts by mass of the total of epoxy resin (A) and epoxy resin (B), more preferably in the range of 5 to 30 parts by mass, even more preferably in the range of 6 to 20 parts by mass, and particularly preferably in the range of 7 to 15 parts by mass, 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, and without causing the particle to expand sufficiently during dismantling after use to reduce the adhesiveness.

[0211] [Glycidyl ether group-containing compound (E)] The glycidyl ether group-containing compound (E) is a glycidyl ether group-containing compound in which a structural unit V having one or more glycidyl ether groups and a structural unit W different from the structural unit V are linked by VWV, wherein the structural unit W and the structural unit V are linked by a reversible bond, and it is preferable that the bond is formed by a reversible bond between a furan structure and a maleimide structure via a Diels-Alder reaction.

[0212] The glycidyl ether group-containing compound (E) is incorporated into the crosslinked structure by a curing reaction based on its glycidyl ether group. On the other hand, it retains reversibility even after curing, and therefore exhibits high molecular mobility within the cured product. Consequently, if the cured product is exposed to high temperatures or subjected to impact, resulting in cracking or pulverization, the reversible bonds are broken, exhibiting decomposition properties. Conversely, the reversible bonds are reversibly reformed in low-temperature ranges, including room temperature, resulting in excellent adhesion.

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

[0214] [ka]

[0215] In the aforementioned Diels-Alder reaction, a conjugated diene and a parent diene undergo an addition reaction to form a six-membered ring. Since the Diels-Alder reaction is an equilibrium reaction, a Retro-Diels-Alder reaction occurs at a predetermined temperature, leading to dissociation (de-crosslinking). When mechanical energy, such as scratching or external force, is applied to the resulting cured product, the CC bonds of the Diels-Alder reaction unit are preferentially cleaved because their bond energy is lower than that of ordinary covalent bonds. As a result, the cured product exhibits decomposition properties. Furthermore, in the temperature range below the dissociation temperature, the equilibrium shifts in the bond direction of the CC bonds of the Diels-Alder reaction unit, causing it to re-form an adduct (Diels-Alder reaction unit).

[0216] In the reversible bonding by the Diels-Alder reaction described above, the reversible bonding with the furan structure and maleimide structure via the Diels-Alder reaction dissociates (de-crosslinks) at around 120°C due to a retro-Diels-Alder reaction. Therefore, the heating temperature required for the cured product to exhibit easy disassembly properties can be reduced, resulting in excellent disassembly properties for applications where high-temperature heating is unsuitable.

[0217] The aforementioned reversible bonds will be present in at least two locations in the target glycidyl ether group-containing compound (E). However, from the viewpoint of excellent adhesion, flexibility, and decomposition properties of the cured product, it is preferable that the structural unit W also has multiple such reversible bonds.

[0218] Furthermore, for the same reasons as described above, it is preferable that the molecular weight of the structural unit W is above a certain size, for example, that its average molecular weight (Mw) is 28 or more. If the structural unit W has reversible bonds, it is preferable that the molecular weight between the reversible bonds is 28 or more. Although the structural unit W may contain crosslinking functional groups similar to the glycidyl ether group in the structural unit V, it is preferable that the structural unit W does not have crosslinking (curing) functional groups from the viewpoint of more easily exhibiting the effects of the present invention.

[0219] The structural unit W may contain an alkylene chain or an alkylene ether chain, for example, when the glycidyl ether group-containing compound (E) of the present invention is used as a structural adhesive, from the viewpoint of excellent adhesion, flexibility, and decomposition properties of the cured product. In this case, the alkylene chain is more preferably 2 to 30 carbon atoms, and most preferably 4 to 16 carbon atoms. The alkylene ether chain is not particularly limited, but is preferably an alkylene ether chain with 2 to 12 carbon atoms, and its average number of repeats 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 decomposability of the 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 from the viewpoint of adhesive strength, decomposability, and flexibility of the resulting cured product, it is preferably less than 1000.

[0222] The epoxy equivalent of the glycidyl ether group-containing compound (E) is preferably 150 to 1000 g / equivalent, more preferably in the range of 180 to 800 g / equivalent, and even more preferably in the range of 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] [ka] [In equation (4), m3 is an integer between 1 and 4. Z 1 This is given by the following equation (5), Z 3The structure is one of the structures represented by the following formula (6), and each of the multiple structures in a single molecule may be the same or different. Furthermore, either of the maleimide structures at both ends of formula (4) may or may not have a substituent. If a substituent is present, preferred substituents include alkyl groups, halogen atoms, glycidyl ether groups, 2-methylglycidyl ether groups, etc.

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

[0226] [ka] (In formula (6), R'' is independently a hydrogen atom, a methyl group, or an ethyl group; w1 is an integer from 1 to 30; w2 is the average value of the number of repetitions, from 0.5 to 8; w3 is the average value of the number of repetitions, from 0.5 to 6; and * represents a bond point.)

[0227] Among these, from the viewpoint of ease of raw material availability and the mechanical properties of the resulting cured product, it is preferable that w1 is in the range of 1 to 15, w2 is in the range of 0.5 to 3, w3 is an integer from 1 to 4, and R'' is a hydrogen atom.

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

[0229] Z in the formula 1This is a structural unit having a glycidyl ether group or a 2-methylglycidyl ether group, represented by the general formula (5) above. Among these, the one with the following structural formula is preferred from the viewpoint of the ease of obtaining raw materials and the reactivity of the glycidyl group during the curing of the epoxy resin composition. G is a glycidyl group or a 2-methylglycidyl group.

[0230] [ka]

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

[0232] [ka]

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

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

[0235] The Diels-Alder reaction, in which a conjugated diene such as the furan structure is added to a parent diene such as the maleimide structure to form a six-membered ring, is an equilibrium reaction. It is well known that at temperatures higher than the temperature at which the addition reaction proceeds, a reverse reaction, the Retro-Diels-Alder reaction, proceeds, in which the addition reaction site dissociates and returns to the original conjugated diene and parent diene.

[0236] The Diels-Alder reaction can be carried out using known methods. For example, a conjugated diene compound and a parent diene compound are mixed in equimolar amounts, or in some cases, with an excess of one component, and the mixture is heated and melted or dissolved in a solvent, and the reaction product is obtained by stirring at a temperature of room temperature to 110°C for 1 to 24 hours. The reaction product can be obtained by filtration or solvent removal without purification, or by commonly used isolation and purification methods such as recrystallization, reprecipitation, and chromatography.

[0237] The phrase "equomoles 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 in equimolar amounts. For example, in the case of the glycidyl ether group-containing compound (E) represented by the general formula (4) above, if 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, then "equomoles of the conjugated diene compound and the parent diene compound" means that the furan compound and the maleimide compound (bismaleimide) are in a molar ratio of 2:1.

[0238] <Z 1 A furan compound having the structure > Z 1 The structure (Z in the general formula (4) above) 1 A furan compound having the same properties as the above is obtained by reacting a furan compound having a hydroxyl group with epihalohydrin (a3), thereby converting the hydroxyl group in the furan compound to a glycidyl ether group. Examples of furan compounds having a hydroxyl group include any of the compounds listed in the following formula. The hydroxyl group in these compounds can be converted to a glycidyl ether group by known methods, such as those described in the examples.

[0239] [ka]

[0240] Among the compounds shown in the above formulas, the following compounds are particularly preferred due to their excellent reactivity and the superior adhesion, flexibility, and decomposability of the resulting cured product.

[0241] [ka]

[0242] The structures of the above furan compounds include those in which each independently has a hydrogen atom, halogen atom, alkoxy group, aralkyloxy group, aryloxy group, nitro group, amide group, alkyloxycarbonyl group, aryloxycarbonyl group, cyano group, alkyl group, cycloalkyl group, aralkyl group, or aryl group as a substituent. Furthermore, in the structures of the compounds listed in the above formula, the alkoxy group, aralkyloxy group, aryloxy group, carboxyl group, alkyloxycarbonyl group, aryloxycarbonyl group, alkyl group, cycloalkyl group, aralkyl group, and aryl group also include those in which various substituents are further bonded to the carbon atoms they possess.

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

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

[0245] <Z 3 Maleimide compounds (bismaleimides) having the structure > Said Z 3 The structure (Z in the general formula (4) above) 3Maleimide compounds (bismaleimides) having the same property are intermediates of the parent diene before the Diels-Alder reaction, and can be represented by the following general formula (1)', for example.

[0246] [ka] [In the formula, Z 3 Z in the general formula (4) is 3 It is the same as [this].

[0247] The maleimide compound described above is preferably one with the following structure, from the viewpoint of ease of obtaining raw materials, solvent solubility during the Diels-Alder reaction, and adhesive strength when the compound obtained by the Diels-Alder reaction is cured.

[0248] [ka]

[0249] Said Z 3 Maleimide compounds (bismaleimides) having this structure may be commercially available or synthesized.

[0250] Examples of commercially available maleimide compounds include: maleimide compounds from Yamato Kasei Co., Ltd. (product 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 from Kei-I Kasei (product names: BMI, BMI-70, BMI-80), maleimide compounds from JFE Chemical (product names: JBM-200N, JBM-300N, JBM-800N), and DESIGNER Examples include maleimide compounds manufactured by Molecules (trade names: BMI-689, BMI-1400, BMI-1500, BMI-1700, BMI-3000, BMI-5000, etc.).

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

[0252] "First method" In the first method described above, for example, formula: NH2-Z 3 The diamine compound represented by -NH2 and maleic anhydrides can be synthesized by known methods. For example, the diamine compound and maleic anhydrides can be reacted in a solvent under an acid catalyst to form maleamic acid, which is then maleimidized (ring-closing by dehydration) using an acid catalyst to obtain a crude maleimide compound solution, which is then purified to synthesize the compound. Examples of maleic anhydrides 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 hydroxyl groups at both ends as the compound having the two functional groups S (SNS), and using glycidyloxyphenylmaleimide as the maleimide compound having the functional group T (T-MI). The hydroxyl groups of the compound having hydroxyl groups at both ends can be reacted with the glycidyloxy groups of glycidyloxyphenylmaleimide to introduce a maleimide structure at the end.

[0254] Compounds having hydroxyl groups at both ends can be synthesized, for example, by the following method: A compound having hydroxyl groups at the ends can be obtained by reacting a diglycidyl ether or aliphatic divinyl ether of an aliphatic dihydroxy compound with an aromatic hydroxy compound.

[0255] Alternatively, the maleimide compound (bismaleimide) can be synthesized by using a compound having glycidyl ether groups at both ends as the compound having the two functional groups S (SNS), and using hydroxyphenylmaleimide as the maleimide compound having the functional group T (T-MI). For example, after obtaining the compound having hydroxyl groups at both ends, it can be epoxidized to make the ends glycidyl ether groups, and then a maleimide structure can be introduced at the ends by reacting it with hydroxyphenylmaleimide or the like.

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

[0257] The diglycidyl ether of the aliphatic dihydroxy compound is not particularly limited, and for example, the same specific examples as the diglycidyl etherified product (a1) of the dihydroxy compound having an alkylene chain and a polyether chain can be cited.

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

[0259] The aliphatic divinyl ether is not particularly limited and includes, for example, divinyl ethers with 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 with branched alkylene groups such as neopentyl glycol divinyl ether, divinyl ether containing cycloalkane structures such as 1,4-cyclohexanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, tricyclodecanediol divinyl ether, tricyclodecanedimethanol divinyl ether, pentacyclopentadecanedimethanol divinyl ether, and pentacyclopentadecanediol divinyl ether, and bisphenol A divinyl ether, bisphenol F divinyl ether, and hydroquinone divinyl ether, which may be used alone or in combination of two or more types.

[0260] Among these, polyether structures or divinyl ethers with linear alkylene chains having 4 to 10 carbon atoms are preferred in terms of excellent adhesion, flexibility, and decomposability of the resulting cured product, and most preferably 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, and 1,10-decanediol divinyl ether are used.

[0261] The aforementioned aromatic hydroxy compound is not particularly limited, and for example, the same specific example as the aromatic hydroxy compound (a2) can be given.

[0262] Among these, bisphenols are preferred due to their excellent adhesion, flexibility, and decomposability when cured, and bis(4-hydroxyphenyl)methane and 2,2-bis(4-hydroxyphenyl)propane are particularly preferred due to their remarkable toughness-imparting properties. Furthermore, when moisture resistance of the cured product is important, 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 within the range of 1 / 1.01 to 1 / 5.0 (molar ratio) for the former / latter, and it is preferable that (a1) / (a2) is 1 / 1.02 to 1 / 3.0 (molar ratio) in order to obtain a cured product that has a good balance of flexibility and heat resistance.

[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. Examples of such catalysts include those described above in "Catalysts used in the reaction between (a1) and (a2)".

[0265] Furthermore, the reaction between the diglycidyl ether of the aliphatic dihydroxy compound and the aromatic hydroxy compound can be carried out without a solvent or in the presence of an organic solvent. Examples of organic solvents that can be used are those described above in "Solvents used in the reaction between (a1) and (a2)". The amount of organic solvent used is usually 50 to 300% by mass, preferably 100 to 250% by mass, relative to the total mass of the raw materials charged. These organic solvents may be used alone or in combination of two or more. To carry out the reaction quickly, it is preferable to use no solvent, while the use of dimethyl sulfoxide is preferable in that it can reduce impurities in the final product.

[0266] The reaction temperature for the above reaction is usually 50 to 180°C, and the reaction time is usually 1 to 10 hours. A reaction temperature of 100 to 160°C is preferred in order to reduce impurities in the final product. If the resulting compound is highly discolored, antioxidants or reducing agents may be added to suppress this discoloration. Antioxidants are not particularly limited, but examples include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite ester compounds containing trivalent phosphorus atoms. Reducing agents are not particularly limited, but examples include hypophosphorous acid, phosphite, thiosulfite, sulfite, hydrosulfite, or salts thereof.

[0267] After the reaction is complete, the reaction mixture may be neutralized or washed with water until its pH is 3 to 7, preferably 5 to 7. Neutralization and washing can be carried out according to conventional methods. For example, when a basic catalyst is used, acidic substances such as hydrochloric acid, sodium monohydrogen phosphate, p-toluenesulfonic acid, or oxalic acid can be used as neutralizing agents. After neutralization or washing, the solvent can be removed under reduced pressure and heating if necessary to concentrate the product and obtain the compound.

[0268] The reaction ratio of the aliphatic divinyl ether to the aromatic hydroxy compound is preferably within the range of 1 / 1.01 to 1 / 5.0 (molar ratio), and it is preferable that (a1) / (a2) is 1 / 1.02 to 1 / 3.0 (molar ratio) in order to obtain a cured product that has a good balance of flexibility and heat resistance.

[0269] The reaction between the diglycidyl ether of the aliphatic dihydroxy compound and the aromatic hydroxy compound proceeds sufficiently without the use of a catalyst, but a catalyst may be used as appropriate to improve the selection of starting materials and the reaction rate. Examples of catalysts that can be used here 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 in 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 so as not to cause a nucleation reaction of the vinyl group to the aromatic ring.

[0270] Furthermore, the reaction between the aliphatic divinyl ether and the aromatic hydroxy compound can be carried out without a solvent or in the presence of an organic solvent. Examples of organic solvents used include those described above in "Solvents used in the reaction between (a1) and (a2)". The amount of organic solvent used is usually 50 to 300% by mass, preferably 100 to 250% by mass, relative to the total mass of the raw materials. These organic solvents may be used individually or in combination of two or more types.

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

[0272] After the reaction is complete, if an organic solvent was used, it can be removed under reduced pressure heating. If a catalyst was used, it can be deactivated with an inactivator or the like as necessary, and then removed by washing with water or filtration to obtain the compound.

[0273] When the compound having two or more functional groups S (SNS) 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, etc. At this time, sodium hydroxide, potassium hydroxide, potassium carbonate, etc. can be used as a catalyst, and toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetonitrile, dimethylformamide, etc. may be used as a solvent. The reaction temperature is room temperature to 200°C, and the reaction time is 1 to 24 hours. After that, the catalyst is removed by filtration, etc., and the target compound can be obtained by extraction, solvent removal, etc. The Diels-Alder reaction with this compound is as described above.

[0274] The aliphatic hydroxy compounds are not particularly limited, and include, for example, 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-hexadecanediol. Examples include diols, 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, polyheptamethylene glycol diglycidyl ether, etc., which may be used individually or in combination of two or more types.

[0275] Among these, it is preferable to use a polyether structure or a dihydroxy compound of a linear alkylene chain having 12 to 14 carbon atoms, as these compounds offer excellent adhesion, flexibility, and decomposability of the resulting cured product. The most preferred materials are polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,12-dodecanediol, 1,13-tridecanediol, and 1,14-tetradecanediol.

[0276] The aforementioned alkyl dihalide compounds are not particularly limited, and examples 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, 1,12-dibromododecane, etc., and may be used alone or in combination of two or more.

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

[0278] The reaction ratio of the aromatic dihydroxy compound to the dihalogenated alkyl compound or the dihalogenated aralkyl compound is preferably within the range of 1 / 1.01 to 1 / 5.0 (molar ratio) for the former / latter, and is preferably (a1) / (a2) is 1 / 1.02 to 1 / 3.0 (molar ratio) in order to obtain a cured product that has a good balance of flexibility and heat resistance.

[0279] The reaction between the aromatic dihydroxy compound and the alkyl dihalide compound or the aralkyl dihalide compound is preferably carried out in the presence of a catalyst. Various catalysts can be used, such as 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 may be used alone or in combination of two or more. Among these, sodium hydroxide, potassium hydroxide, and potassium carbonate are preferred because the reaction proceeds rapidly and they have a high effect in reducing the amount of impurities. The amount of these catalysts used is not particularly limited, but it is preferable to use 0.0001 to 10 moles per mole of phenolic hydroxyl group of the aromatic hydroxy compound. The form of these catalysts is also not particularly limited and may be used in aqueous solution form or in solid form.

[0280] Furthermore, the reaction between the aromatic dihydroxy compound and the alkyl dihalide compound or the aralkyl dihalide compound can be carried out without a solvent or in the presence of an organic solvent. Examples of organic solvents used include those described above in "(a1) and (a2) solvents". The amount of organic solvent used is usually 50 to 300% by mass, preferably 100 to 1000% by mass, relative to the total mass of the raw materials. These organic solvents may be used individually or in combination of two or more types.

[0281] The reaction temperature for the above 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, a reaction temperature of room temperature to 100°C is preferred.

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

[0283] The obtained Z 3 The maleimide group equivalent of a maleimide compound having the structure is preferably 100 to 1000, more preferably in the range of 110 to 800, and even more preferably in the range of 120 to 500.

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

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

[0286] [Hardening agent (F)] The epoxy resin composition according to this embodiment preferably further contains a curing agent (F) that can react with epoxy groups. The curing agent (F) may have a reversible bond. An example of the reversible bond in 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 the epoxy group, and examples include amine compounds, acid anhydrides, amide compounds, phenolic hydroxyl group-containing compounds, carboxylic acid compounds, thiol compounds, etc. However, the amine compound does not include the heterocyclic aromatic compound (C) having a tertiary amino group that is included in the epoxy resin composition according to this embodiment.

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

[0289] Examples of the amine compounds 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, α-methylbenzylmethylamine, and other aliphatic amine compounds;

[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 epoxy compound addition reactions), Michael addition-modified polyamines (polyamines modified by Michael addition reactions), Mannich-modified polyamines (polyamines modified by Mannich addition reactions), thiourea-modified polyamines (polyamines modified by thiourea addition reactions), and ketone-modified polyamines (polyamines modified by ketone blockade reactions);

[0293] Examples include dicyandiamide, guanidine, organic acid hydrazides, diaminomaleonitriles, amineimides, boron trifluoride-piperidine complexes, boron trifluoride-monoethylamine complexes, and other amine compounds.

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

[0295] Examples of the amide compound include polyamidoamines. Examples of polyamidoamines include those obtained by reacting aliphatic polyamines or polyamines having polyoxyalkylene chains.

[0296] The phenolic hydroxyl group-containing compound is not particularly limited, and for example, the same specific examples as the aromatic hydroxy compound (a2) can be given.

[0297] Examples of the carboxylic acid compounds include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and azelaic acid, as well as 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 is preferably one that contains two or more thiol groups in one molecule. Examples 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)glycoluryl, 4-butanedithiol, 1,6-hexanedithiol, and 1,10-decandithiol.

[0299] When using the curing agent (F), the curing agent may be used alone or in combination of two or more types. For applications such as underfill materials and general paints, it is preferable to use the amine compound, acid anhydride, and / or carboxylic acid compound. Furthermore, for adhesives and flexible wiring board applications, the amine compound, particularly dicyandiamide, is preferred in terms of workability, curability, and long-term stability. For semiconductor encapsulation material applications, a solid type phenolic hydroxyl group-containing compound is preferred in terms of the heat resistance of the cured product. In applications requiring low-temperature curing, such as battery adhesives, the aliphatic amine compound or the thiol compound is preferred.

[0300] Furthermore, if the epoxy resin composition according to this embodiment contains the glycidyl ether group-containing compound (E), it is preferable that the curing agent (F) is an amino group-containing compound and / or a phenolic hydroxyl group-containing compound having a reversible bond, from the viewpoint of being able to express its effects even more effectively.

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

[0302] Examples of phenolic hydroxyl group-containing compounds having the reversible bond include phenolic hydroxyl group-containing compounds in which structural units V' and W' are linked by V'-W'-V'. The structural unit V' has one or more hydroxyl groups, and the structural units V' and W' are different. The structural units V' and W' are linked by the reversible bond. The reversible bond can be the same as the reversible bond in the glycidyl ether group-containing compound (E) in this embodiment. That is, the structural unit V' and W' may be linked by 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 may use other epoxy resins other than the epoxy resin (A), epoxy resin (B), and glycidyl ether group-containing compound (E) according to this embodiment, as long as the effects of this embodiment are not impaired. If the epoxy resin composition according to this embodiment does not contain the glycidyl ether group-containing compound (E), the total amount of epoxy resin (A) and 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. Also, if the epoxy resin composition according to this embodiment contains the glycidyl ether group-containing compound (E), the total amount of epoxy resin (A), epoxy resin (B), and 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.

[0304] The aforementioned other epoxy resins are not limited in any way other than not belonging to epoxy resin (A), epoxy resin (B), or glycidyl ether group-containing compound (E), and include, for example, liquid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD ​​type epoxy resin, polyhydroxybenzene type epoxy resin, polyhydroxynaphthalene type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, brominated epoxy resins such as brominated phenol novolac type epoxy resin, solid bisphenol A type epoxy resin, and phenol novolac type epoxy resin. Examples include cresol novolac type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, phenol aralkyl type epoxy resin, phenylene ether type epoxy resin, naphthylene ether type epoxy resin, naphthol novolac type epoxy resin, naphthol aralkyl type epoxy resin, naphthol-phenol copolymer novolac type epoxy resin, naphthol-cresol copolymer novolac type epoxy resin, biphenyl-modified novolac type epoxy resin, etc. These can be used individually or in combination of two or more types, and it is preferable to select and use them according to the intended application and the physical properties of the cured product.

[0305] In this embodiment, the concentration of reversible bonds in the epoxy resin composition is preferably 0.10 mmol / g or more relative to the total mass of curable components in the epoxy resin composition. With such a configuration, the adhesion, flexibility, and decomposability of the cured product obtained from the epoxy resin composition are all further improved. The concentration of the aforementioned 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) has multiple reversible bonds, or when the aforementioned phenolic hydroxyl group-containing compound having reversible bonds is used alone or in combination with other curing agents as a curing agent, the total concentration of such 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 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 tanδ peak top of the dynamic viscoelasticity measuring instrument (DMA) of the target cured product. For example, if the glass transition temperature is used as a guideline, if the glass transition temperature of the cured product is near room temperature, sufficient adhesion, flexibility, and decomposition properties are likely to be exhibited even at the lower end of the preferred range of concentrations. 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 higher end of the preferred range of concentrations. However, in the temperature range above the glass transition temperature measured by DMA, molecular mobility is generally high, and sufficient adhesion, flexibility, and decomposition properties are likely to be exhibited even at low concentrations of the glycidyl ether group-containing compound (E). Therefore, the effect of exhibiting adhesion, flexibility, and decomposition properties can also be adjusted by appropriately adjusting the aging temperature for repair or the heating temperature for reshaping. 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 that can react with these epoxy groups in the epoxy resin composition according to this embodiment is not particularly limited, but from the standpoint of good mechanical properties of the resulting cured product, it is preferable that the amount of functional groups that can react with epoxy groups is 0.4 to 1.5 equivalents per 1 equivalent of the total epoxy groups in the resin composition. The functional groups that can react 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, but examples include urea compounds, phosphorus compounds, tertiary amines, organic acid metal salts, Lewis acids, amine complex salts, and the like.

[0308] Examples of the urea compounds 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 compounds include alkylphosphines such as ethylphosphine and butylphosphine, primary phosphines such as phenylphosphine; dialkylphosphines 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 aforementioned tertiary amines include triethylamine, N,N-dimethylbenzylamine, N,N-diethylbenzylamine, 1,8-diazabicyclo[5.4.0]undecene, and 1,4-diazabicyclo[2.2.2]octane, among other tertiary amines.

[0311] Examples of the aforementioned metal organic acid salts include cobalt organic acid salts such as cobalt thiocyanate, cobalt octoate, cobalt naphthenate, and cobalt acetate; copper organic acid salts such as copper naphthenate; manganese organic acid salts such as manganese naphthenate; and vanadium organic acid 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 salts include boron trifluoride monoethylamine complex, boron trifluoride diethylamine complex, boron trifluoride isopropylamine complex, boron trifluoride chlorophenylamine complex, boron trifluoride benzylamine complex, boron trifluoride aniline complex, or mixtures thereof, and other boron trifluoride complexes.

[0314] When used as an adhesive, urea compounds, particularly 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), are preferred due to their excellent workability and low-temperature curing properties. When used as a semiconductor encapsulating material, triphenylphosphine is preferred among phosphorus compounds, and 1,8-diazabicyclo-[5.4.0]-undecene (DBU) is preferred among tertiary amines due to their excellent curability, heat resistance, electrical properties, and moisture resistance reliability.

[0315] [Other thermosetting resins and thermoplastic resins] Furthermore, the epoxy resin composition according to this embodiment may also be used in combination with other thermosetting resins or thermoplastic resins, as long as this does not hinder the effects of this embodiment.

[0316] Other thermosetting resins include, for example, cyanate ester resins, resins having a benzoxazine structure, activated ester resins, vinyl benzyl compounds, acrylic compounds, and the like. When using any of the above-mentioned other thermosetting resins in combination, the amount used is not particularly limited as long as it does not hinder the effects of this embodiment, but it 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 resins 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, and cresol novolac. Examples include cyanate ester resins of type k, triphenylmethane, tetraphenylethane, dicyclopentadiene-phenol addition reaction, phenol aralkyl, naphthol novolac, naphthol aralkyl, naphthol-phenol co-condensed novolac, naphthol-cresol co-condensed novolac, biphenyl-modified novolac, and anthracene. These can be used individually or in combination of two or more types.

[0318] Among the aforementioned cyanate ester resins, bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, bisphenol E type cyanate ester resin, polyhydroxynaphthalene type cyanate ester resin, naphthylene ether type cyanate ester resin, and novolac type cyanate ester resin are preferred for obtaining cured products with particularly excellent heat resistance, and dicyclopentadiene-phenol addition reaction type cyanate ester resin is preferred for obtaining cured products with excellent dielectric properties.

[0319] There are no particular limitations on the resin having the benzoxazine structure, but examples include the reaction product of bisphenol F, formalin, and aniline (Fa-type benzoxazine resin), the reaction product of diaminodiphenylmethane, formalin, and phenol (Pd-type benzoxazine resin), the reaction product of bisphenol A, formalin, and aniline, the reaction product of dihydroxydiphenyl ether, formalin, and aniline, the reaction product of diaminodiphenyl ether, formalin, and phenol, the reaction product of dicyclopentadiene-phenol addition resin, formalin, and aniline, the reaction product of phenolphthalein, formalin, and aniline, and the reaction product of diphenyl sulfide, formalin, and aniline. These may be used individually or in combination of two or more types.

[0320] There are no particular restrictions on the activated ester resin, but generally, compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are preferred. The activated ester resin is preferably 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. Particularly from the viewpoint of improving heat resistance, activated ester resins obtained from a carboxylic acid compound or its halide and a hydroxy compound are preferred, and activated 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, etc., or their halides. 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 addition resins.

[0321] Specifically, the active ester resins are preferably active ester resins containing a dicyclopentadiene-phenol addition structure, active ester resins containing a naphthalene structure, active ester resins which are acetylated phenol novolacs, and active ester resins which are benzoylated phenol novolacs. Among these, active ester resins containing a dicyclopentadiene-phenol addition structure and active ester resins containing a naphthalene structure are more preferred in that they are excellent at improving peel strength.

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

[0323] The thermoplastic resins mentioned above refer to resins that can be melt-molded by heating. Specific examples 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 individually or in combination of two or more types.

[0324] When using the aforementioned other resins and including the glycidyl ether group-containing compound (E), the blending ratio of the glycidyl ether group-containing compound (E) in this embodiment to the aforementioned other resins can be arbitrarily set according to the application. However, from the viewpoint of excellent adhesion, flexibility, and decomposability when cured, it is preferable that the ratio of the aforementioned other resins 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-halogenated flame retardant] When the epoxy resin composition according to this embodiment is used in applications requiring high flame retardancy, a non-halogen flame retardant that substantially does not contain halogen atoms may be incorporated.

[0326] Examples of the non-halogenated flame retardants include phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, organometallic salt-based flame retardants, etc. There are no restrictions on their use; they may be used alone or in combination of two or more types.

[0327] The phosphorus-based flame retardant can be either an inorganic compound or an organophosphorus compound. Examples of the inorganic compound include ammonium phosphates such as red phosphorus, monoammonium phosphate, diammonium phosphate, triammonium phosphate, and polyammonium phosphate, as well as inorganic nitrogen-containing phosphorus compounds such as phosphate amides.

[0328] Furthermore, it is preferable that the red phosphorus is surface-treated to prevent hydrolysis and the like. Examples of surface treatment methods include (i) 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) coating with a mixture of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide, and a thermosetting resin such as phenolic resin; and (iii) double coating with a thermosetting resin such as phenolic resin on top of a coating of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide.

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

[0330] The amount of 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 degree of flame retardancy. For example, in 100 parts by mass of the epoxy resin composition according to this embodiment, when red phosphorus is used as a non-halogen-based flame retardant, it is preferable to blend it in the range of 0.1 to 2 parts by mass. Similarly, when an organophosphorus compound is used, it is preferable to blend it in the range of 0.1 to 10.0 parts by mass, and more preferably in the range of 0.5 to 6.0 parts by mass.

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

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

[0333] The aforementioned triazine compounds include, for example, melamine, acetoganamine, benzoguanamine, melon, melam, succinoguanamine, ethylenedimelamine, polyphosphate melamine, triguanamine, etc., as well as, for example, (1) sulfate aminotriazine compounds such as guanylmelamine sulfate, melem sulfate, and melam sulfate; (2) co-condensates of phenols such as phenol, cresol, xylenol, butylphenol, and nonylphenol, and melamines such as melamine, benzoguanamine, acetoganamine, and formuanamine, and formaldehyde; (3) mixtures of the co-condensates of (2) and phenol resins such as phenol-formaldehyde condensates; and (4) the above (2) and (3) further modified with tung oil, isomerized linseed oil, etc.

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

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

[0336] When using the aforementioned nitrogen-based flame retardant, metal hydroxides, molybdenum compounds, etc., may be used in combination.

[0337] The silicone-based flame retardant can be any organic compound containing silicon atoms, and examples include silicone oil, silicone rubber, and silicone resin. The amount of the silicone-based flame retardant is appropriately selected depending on the type of silicone-based flame retardant, the other components of the resin composition, and the desired degree of flame retardancy. For example, it is preferable to include it in the range of 0.05 to 20 parts by mass per 100 parts by mass of the resin composition containing the non-halogen-based flame retardant and all other fillers and additives. Furthermore, when using the silicone-based flame retardant, molybdenum compounds, alumina, etc., may be used in combination.

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

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

[0340] Examples of the aforementioned metal oxides 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 aforementioned metal carbonate compounds 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 aforementioned metal powders include aluminum, iron, titanium, manganese, zinc, molybdenum, cobalt, bismuth, chromium, nickel, copper, tungsten, and tin.

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

[0344] Examples of the low-melting-point glass include glassy compounds such as Sheeplee manufactured by Air Brown Co., Ltd., hydrated glass SiO2-MgO-H2O, PbO-B2O3 system, ZnO-P2O5-MgO system, P2O5-B2O3-PbO-MgO system, P-Sn-OF system, PbO-V2O5-TeO2 system, Al2O3-H2O system, and lead borosilicate system.

[0345] The amount of inorganic flame retardant to be blended is appropriately selected depending on the type of inorganic flame retardant, the other components of the resin composition, and the desired degree of flame retardancy. For example, it is preferable to blend it 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-halogenated flame retardant and all other fillers and additives.

[0346] Examples of the organometallic salt-based flame retardants include ferrocene, acetylacetonate metal complexes, organometallic carbonyl compounds, organocaltate compounds, organosulfonic acid metal salts, and compounds in which a metal atom and an aromatic compound and / or a heterocyclic compound are ionically bonded and / or coordinately bonded.

[0347] The amount of the organometallic salt flame retardant is appropriately selected depending on the type of organometallic salt flame retardant, the other components of the resin composition, and the desired degree of flame retardancy. For example, it is preferable to include it in an amount of 0.005 parts by mass to 10 parts by mass in 100 parts by mass of the resin composition containing the non-halogenated flame retardant and all other fillers and additives.

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

[0349] Examples of the aforementioned inorganic fine particles include, for example, those with excellent heat resistance, alumina, magnesia, titania, zirconia, silica (quartz, fumed silica, precipitated silica, anhydrous silicic acid, fused silica, crystalline silica, ultrafine amorphous silica, etc.); those with excellent thermal conductivity, boron nitride, aluminum nitride, aluminum oxide, titanium oxide, magnesium oxide, zinc oxide, silicon oxide, diamond, etc.; those with excellent electrical conductivity, metal fillers and / or metal-coated fillers using elemental metals or alloys (e.g., iron, copper, magnesium, aluminum, gold, silver, platinum, zinc, manganese, stainless steel, etc.); and those with excellent barrier properties, such as minerals like mica, clay, kaolin, talc, zeolite, wollastonite, smectite, potassium titanate, magnesium sulfate, sepiolite, zonolite, and others. Examples of inorganic nanoparticles include: ion, aluminum borate, calcium carbonate, titanium dioxide, barium sulfate, zinc oxide, and magnesium hydroxide; those with high refractive index include barium titanate, zirconia oxide, and titanium dioxide; 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 the aforementioned metals and their oxides; those with excellent wear resistance include metals such as silica, alumina, zirconia, and magnesium oxide, and their composites and oxides; 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 dioxide and zinc oxide. These inorganic nanoparticles can be selected as appropriate depending on the application, and may be used individually or in combination of multiple types. Furthermore, since the above inorganic nanoparticles have various properties other than those listed as examples, they should be selected as appropriate for the application.

[0350] When using silica as the inorganic fine particles, for example, there are no particular limitations, and known silica fine particles such as powdered silica or 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 Co., Ltd. (product name: SYLYSIA470), and silica fine particles manufactured by Nippon Sheet Glass Co., Ltd. (product name: SG Flake).

[0351] Furthermore, commercially available colloidal silica can be found in the form of methanol silica sol manufactured by Nissan Chemical Corporation (product 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, ST-OL).

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

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

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

[0355] Examples of organic fillers include polyacrylate particles, co-encapsulated polyacrylate particles, polystyrene particles, acrylic-styrene copolymer particles, polypropylene particles, polyethylene particles, and the like.

[0356] [fibrous matrix] The epoxy resin composition according to this embodiment may further contain a fibrous substrate. The fibrous substrate is not particularly limited, but those used in fiber-reinforced resins are preferred, and examples include inorganic fibers and organic fibers.

[0357] Examples of inorganic fibers include carbon fibers, glass fibers, boron fibers, alumina fibers, 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 metal fibers include aluminum fibers, copper fibers, brass fibers, stainless steel fibers, and steel fibers.

[0358] Examples of the aforementioned organic fibers include synthetic fibers made from resin materials such as polybenzazole, aramid, PBO (poly-p-phenylenebenzoxazole), 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 proteins, polypeptides, and alginic acid.

[0359] Among these, carbon fibers and glass fibers are preferred because they have a wide range of industrial applications. The fibrous substrate may be of one type or multiple types may be used simultaneously.

[0360] The fibrous matrix may be an aggregate of fibers, and the fibers may be continuous or discontinuous, and may be woven or unwoven. It may also be a bundle of fibers aligned in one direction, or a sheet made of arranged fiber bundles. Furthermore, it may be a three-dimensional shape with thickness given to the aggregate of fibers.

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

[0362] The organic solvents used are those described above in "(a1) and (a2) solvents." These can be used individually or in combination, but methyl ethyl ketone is preferred in terms of volatility during coating and solvent recovery.

[0363] The aforementioned liquid organic polymer is a liquid organic polymer that does not directly contribute to the curing reaction, and examples include acrylic polymers (Floren WK-20: Kyoeisha Chemical), amine salts of specially modified phosphate esters (HIPLAAD ED-251: Kusumoto Chemical), and modified acrylic block copolymers (DISPERBYK2000; BYK).

[0364] [Other ingredients] The resin composition of this embodiment may contain other compounds. Examples include catalysts, polymerization initiators, inorganic pigments, organic pigments, extender pigments, clay minerals, waxes, surfactants, stabilizers, flow regulators and pulling agents, dyes, leveling agents, rheology control agents, UV absorbers, antioxidants, flame retardants, plasticizers, reactive diluents, and the like.

[0365] A cured product can be obtained by curing the resin composition of this embodiment. Curing can be performed at room temperature or by heating. When performing thermal curing, curing may be performed in a single heating step or through a multi-stage heating process.

[0366] The epoxy resin composition according to this embodiment can also be cured using active energy rays. In this case, a photocationic polymerization initiator may be used as the polymerization initiator. As the active energy ray, visible light, ultraviolet light, X-rays, electron beams, etc., can be used.

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

[0368] [Method for preparing epoxy resin compositions] The epoxy resin composition according to this embodiment can be prepared by uniformly mixing the aforementioned components, and the method of preparation is not particularly limited. For example, it can be prepared by uniformly mixing 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 may be made by dissolving the epoxy resin (A), the epoxy resin (B), the heterocyclic aromatic compound having a tertiary amino group (C) if necessary, the thermally expandable particles (D), the glycidyl ether group-containing compound (E) if necessary, the curing agent (F), and optionally the aforementioned compatible curing agents, fillers, fibrous substrates, dispersion media, and resins other than the aforementioned compounds in a dispersion media such as the aforementioned organic solvent, or by mixing and dispersing them under solvent-free conditions (without using a solvent). Mixing and dispersing under solvent-free conditions (without using a solvent) is preferable. Furthermore, the epoxy resin composition according to this embodiment may be made by uniformly mixing the aforementioned constituent materials. In this case, it is preferable to mix them uniformly using a mixer or the like. The mixing ratio of each constituent material can be appropriately adjusted according to the desired properties such as the mechanical strength and heat resistance of the cured product. Furthermore, the specific mixing order of the constituent materials in the preparation of the epoxy resin composition is not particularly limited.

[0370] (Cured product of the epoxy resin composition according to this embodiment) The cured product of the epoxy resin composition according to this embodiment is obtained by curing the epoxy resin composition according to this embodiment, and optionally the curing agent (F). A known curing method can be appropriately selected and adopted.

[0371] As described above, the cured product of this embodiment is cured with the epoxy resin composition according to this embodiment, and by exhibiting an appropriate crosslinking density, it is possible to maintain good mechanical strength.

[0372] The epoxy resin cured product obtained from the epoxy resin (A), the epoxy resin (B), the compound (C) as needed, and the thermally expandable particles (D) exhibits excellent adhesion, flexibility, and decomposability, and also maintains excellent adhesion and decomposability after heat resistance testing. This is thought to be due to the uneven distribution of compound (C) on the surface of the cured product. In particular, when the substrate to be bonded is metal (e.g., iron or aluminum), it is thought that the adhesion strength is improved by the coordination bonding between the substrate surface and compound (C), and that decomposability is exhibited due to the dissociation of the coordination bonds by heat. Due to the effect of this coordination bonding, it is thought that the adhesion and decomposability are excellent not only in the initial state but also after heat resistance testing.

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

[0374] When the epoxy resin composition according to this embodiment contains the glycidyl ether group-containing compound (E), the cured product of this embodiment can be obtained by using the glycidyl ether group-containing compound (E) of 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), and to use a compound that can undergo addition by a Diels-Alder reaction in combination with it to form the glycidyl ether group-containing compound (E) during the curing process (synthesize it in situ) while curing the product.

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

[0376] The epoxy resin composition according to this embodiment and the cured product made from the epoxy resin composition have adhesive properties, flexibility, and decomposability. [Examples]

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

[0378] 1 H and 13 ¹¹¹NMR, FD-MS spectra, and GPC were measured under the following conditions.

[0379] 1 H-NMR: “JNM-ECA600” manufactured by JEOL RESONANCE Magnetic field strength: 600MHz Total number of times: 32 Solvent: DMSO-d6 Sample concentration: 30% by mass

[0380] 13 C-NMR: “JNM-ECA600” manufactured by JEOL RESONANCE Magnetic field strength: 150MHz Total number of times: 320 Solvent: DMSO-d6 Sample concentration: 30% by mass

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

[0382] GPC: HLC-8320GPC manufactured by Tosoh Corporation Column: Tosoh Corporation's "TSK-GEL G2000HXL" + "TSK-GEL G3000HXL" + "TSK-GEL G4000HXL" Detector: RI (Differential Refractive Index) Measurement conditions: 40℃ Mobile phase: tetrahydrofuran Flow rate: 1ml / min Standard: Tosoh Corporation's "PStQuick A", "PStQuick B", "PStQuick E", and "PStQuick F"

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

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

[0385] Examples of methods for calculating the number of repeating units include GPC molecular weight measurement and calculation from the results of appropriate instrumental analyses such as FD-MS and NMR.

[0386] (Synthesis Example 1) In a flask equipped with a thermometer and stirrer, 210 g of 1,12-dodecandiol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g / equivalent) and 123.1 g of bisphenol A (hydroxyl group equivalent 114 g / equivalent) were charged. The mixture was heated to 140°C for 30 minutes, and then 3.4 g of 20% sodium hydroxide aqueous solution was added. The mixture was then heated to 150°C for 30 minutes, and the reaction was continued at 150°C for 16 hours. After that, sodium phosphate was added to neutralize the mixture and obtain the hydroxy compound (Ph-1). Mass spectrometry of this hydroxy compound (Ph-1) yielded a peak at M+=771, corresponding to the theoretical structure of m1=1, n1=12 in the structural formula (Ph-1) below, confirming the presence of the target hydroxy compound. The phenolic hydroxyl group equivalent of this hydroxy compound (Ph-1) was 1980 g / equivalent.

[0387] [ka]

[0388] (Synthesis Example 2) The reaction was carried out in the same manner as in Synthesis Example 1, except that 210 g (0.5 mol) of 1,12-dodecandiol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g / equivalent) and 119.7 g (0.53 mol) of bisphenol A (hydroxyl group equivalent 114 g / equivalent) were replaced with 481 g (0.5 mol) of polypropylene glycol diglycidyl ether (manufactured by Nagase ChemteX, "Denacol EX-931": epoxy equivalent 481 g / equivalent) and 136.8 g (0.6 mol) of bisphenol A (hydroxyl group equivalent 114 g / equivalent), yielding 585 g of the hydroxy compound (Ph-2). The hydroxy compound (Ph-2) was found to contain the target hydroxy compound, as a mass spectrum analysis yielded a peak at M+=1226, corresponding to the theoretical structure of m=1, n2=11 in the structural formula (Ph-2) shown below. The hydroxyl group equivalent of this hydroxy compound (Ph-2), calculated from GPC, was 1447 g / equivalent.

[0389] [ka]

[0390] (Synthesis Example 3) In a flask equipped with a thermometer, dropping funnel, condenser, and stirrer, 198 g of the hydroxy compound (Ph-1) obtained in Synthesis Example 1, 435 g of epichlorohydrin, and 115 g of n-butanol were charged and dissolved under nitrogen gas purging. After raising the temperature to 65°C, the pressure was reduced to the azeotropic pressure, and 6.6 g of 49% sodium hydroxide aqueous solution was added dropwise over 5 hours. Stirring was then continued under the same conditions for 0.5 hours. During this time, the distillate that distilled out 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 continued. Subsequently, the unreacted epichlorohydrin was removed by vacuum distillation. 150 g of methyl isobutyl ketone and 150 g of n-butanol were added to the resulting crude epoxy resin and dissolved. Furthermore, 10 g of 10% sodium hydroxide aqueous solution was added to this solution and reacted at 80°C for 2 hours. After that, the solution was washed three times with 50 g of water until the pH of the washing solution became neutral. Next, the system was dehydrated by azeotrope, and after microfiltration, the solvent was removed by distillation under reduced pressure to obtain the target epoxy resin (Ep-1). The epoxy equivalent of the obtained epoxy resin (Ep-1) was 2308 g / equivalent, the viscosity at 60°C was 400,000 mPa·s, and the total chlorine content was 3.4%. Mass spectrometry of this epoxy resin (Ep-1) yielded a peak at M+=883, which corresponds to the theoretical structure of m1=1, n1=12, p1=0, p2=0, q=1 in the following structural formula (Ep-1), confirming that it contains the target epoxy resin (Ep-1).

[0391] [ka]

[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. Then, the temperature was raised to 65°C, and the pressure was reduced to the azeotropic pressure. 10 g of 49% sodium hydroxide aqueous solution was added dropwise over 5 hours. Next, stirring was continued under the same conditions for 0.5 hours. During this time, the distillate that distilled out 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 continued. Afterward, the unreacted epichlorohydrin was removed by vacuum distillation. 200 g of methyl isobutyl ketone and 100 g of n-butanol were added to the resulting crude epoxy resin and dissolved. Furthermore, 15 g of a 10% sodium hydroxide aqueous solution was added to this solution and reacted at 80°C for 2 hours. After that, the solution was washed three times with 100 g of water until the pH of the washing solution became neutral. Next, the system was dehydrated by azeotropy, and after microfiltration, the solvent was removed by distillation under reduced pressure to obtain epoxy resin (Ep-2). The epoxy equivalent of the obtained epoxy resin (Ep-2) was 1820 g / equivalent, the viscosity at 60°C was 10000 mPa·s, and the total chlorine content was 3.1%. Mass spectrometry of the epoxy resin (Ep-2) yielded a peak at M+=1336, which corresponds to the theoretical structure of m=1, n2=11, p1=0, p2=0, q=1 in the following structural formula (Ep-2), confirming that the epoxy resin (Ep-2) was present.

[0393] [ka]

[0394] (Synthesis Example 5) In a flask equipped with a thermometer, stirrer, and condenser, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane (BMI-THM, manufactured by Yamato Chemical Industries, Ltd.), 30.8 g of furfurylglycidyl ether (manufactured by Kanto Chemical Co., Ltd.), and 80 g of toluene were charged. After purging with nitrogen, the mixture was reacted at 60°C for 12 hours. Subsequently, toluene was removed by vacuum distillation to obtain 61 g of the glycidyl ether group-containing compound (D-1). The mass spectrum of this glycidyl ether group-containing compound showed a peak with M+=626, confirming that it contained the target compound, glycidyl ether group-containing compound (D-1). The epoxy equivalent was 331 g / equivalent.

[0395] [ka]

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

[0397] [ka]

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

[0399] [ka]

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

[0401] [ka]

[0402] <Glue creation, initial adhesive strength measurement> Using the formulations in Tables 1 and 2 (numbers in the tables are by mass), each compound was uniformly mixed in a mixer (Awatori Rentaro ARV-200, manufactured by Thinky Co., Ltd.) to obtain a curable resin composition.

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

[0404] <Tensile elongation> The hardened material was punched out into a dumbbell shape (JIS K 7161-2-1BA) using a punching blade, and these were used as test specimens. Tensile tests were performed on these specimens using a tensile testing machine (Shimadzu Corporation "Autograph AG-IS") in accordance with JIS K 7162-2, and the elongation at the breaking point at a measurement environment of 23°C was evaluated (test speed: 2 mm / min).

[0405] <Observation of phase separation structure> Cross-sections of the cured resin were prepared using an ultramicrotome, and the phase separation structure was observed. The observation method was performed using a scanning electron microscope (SEM). SEM observation can be used to confirm the presence or absence of a phase separation structure in the cured material. If the cured material has a phase separation structure and that structure forms a sea-island structure, the particle size of the island phase was measured. For the average particle size, 50 island phases were arbitrarily selected from the island phase within a 200 μm × 260 μm field of view, and their particle sizes were measured to determine the average particle size. In addition, the relative hardness distribution of the sea phase and island phase can be confirmed from AFM observation.

[0406] [Table 1]

[0407] [Table 2]

[0408] The ingredients listed 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 type liquid epoxy resin (manufactured by DIC Corporation, epoxy equivalent weight 187g / equivalent) SIZ: Imidazole (manufactured by Shikoku Chemicals Co., Ltd.) 1-MZ: 1-Methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) F-190D, F-260D: Thermal expansion capsules (manufactured by Matsumoto Oil & Fat Pharmaceutical Co., Ltd.) GC160 50N: Expanded graphite (manufactured by 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 (DICY7, manufactured by Mitsubishi Chemical Corporation) DTA: Diethylenetriamine (manufactured by Kanto Chemical Co., Ltd.) DCMU: (3-(3,4-dichlorophenyl)-1,1-dimethylurea) (manufactured by DIC Corporation, "B-605-IM")

[0409] <Create adhesive sample> The resin composition was bonded to various substrates under the conditions shown in Tables 3 and 4. One substrate (1.0 mm × 25 mm × 100 mm) was coated with the resin composition, glass beads (Potters Barotini Co., Ltd. "J-80") were added as spacers, and the other substrate was bonded to it (bonding area: 25 mm × 12.5 mm). This was cured at the temperatures specified in Tables 3 and 4 to obtain test specimens. The adhesion was evaluated by performing tensile shear tests on these test specimens. The tests were conducted according to JIS K 6850, and the maximum point stress at a measurement environment of 23°C was compared.

[0410] "Initial adhesive strength": Shear tests were performed on the prepared test specimens without any special treatment.

[0411] "Disassembly during heating" The bonded material was suspended vertically, and a 500g weight was applied to one side of the substrate. Heating was performed using induction heating and a drying oven, and the bonding state of the substrate was evaluated. The heating method and criteria for determining disassembly are as follows.

[0412] <Induction heating> An electromagnetic induction heater (Solary electric equipment "Solary") was used to heat the adhesive material with a 35mm diameter heating coil (voltage 110V, power consumption 1000W). During heating, the surface temperature of the substrate was measured with an infrared thermometer, and heating was stopped when the substrate surface temperature reached 200°C. <Dryer heating> A precision constant temperature chamber (Yamato Scientific "DH611S") was used, the furnace temperature was set to 200°C, and the adhesive was placed inside for 5 minutes to heat.

[0413] <Judgment criteria> A: The adhesive joint shifted, causing the adhesive substrate on the side where the load was applied to fall off. B: The adhesive area has shifted. C: No change occurred in the substrate.

[0414] "Time required for dismantling (time required for the substrate to fall during heating)" The adhesive was suspended vertically, and a 500g weight was applied to one side of the substrate. In this state, induction heating and a drying oven were used, and the time required until the substrate fell due to the load was measured. Details of the heating method are as follows.

[0415] <Induction heating> An electromagnetic induction heater ("Solary" manufactured by Solary Electric Equipment Co., Ltd.) was used to heat the adhesive material with a 35mm diameter heating coil (voltage 110V, power consumption 1000W). During heating, the surface temperature of the substrate was measured with an infrared thermometer, and the output was adjusted so that the surface temperature of the substrate did not exceed 200°C. The time until the substrate fell was then measured.

[0416] <Dryer heating> Using a precision constant temperature chamber (Yamato Scientific "DH611S"), the internal temperature was set to 200°C, the adhesive was placed inside, and the time required until the substrate fell was measured.

[0417] <Judgment criteria> A: The substrate will fall within 1 minute. B: The substrate falls between 1 and 10 minutes. C: No substrate fell at the 10-minute mark.

[0418] "Ease of disassembly when returned to room temperature" The bonded material was suspended vertically, and without applying any load, heating was performed using induction heating and a dryer in the same manner as the "disassembly during heating" evaluation described above. After the substrate was returned to 23°C, the shear bond strength was measured according to JIS K 6850. The bond state of the substrate was evaluated. The rate of strength reduction was calculated using the formula "(initial bond strength - bond strength after heating) / initial bond strength × 100" and evaluated according to the following criteria.

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

[0420] [Table 3]

[0421] [Table 4]

[0422] The ingredients listed in the table are as follows: SPCC-SD: Cold-rolled steel sheet (manufactured by TP Giken Co., Ltd.) A5052: Aluminum plate (manufactured by Engineering Test Service Co., Ltd.) CFRP: Epoxy resin matrix fiber reinforced board (manufactured by Engineering Test Service Co., Ltd.)

[0423] As shown in the table, the resin with a phase separation structure was found to possess excellent flexibility and initial adhesion, and to exhibit decomposition properties through additional heating by induction heating. Furthermore, it was found that the developed product exhibits decomposition effects not only during heating but also after heating. In Comparative Examples 1 to 5, resin compositions were used that did 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. It was found that these compositions exhibited poor initial adhesive strength and low decomposition capabilities. In Comparative Example 6, although the adhesive layer has a phase-separated structure, the time required for easy disassembly to occur during disassembly using a dryer is long, indicating that there are issues with the disassembly time during actual use. From the results of Examples 1-14 and Comparative Examples 1-6, it was found that the combination of a phase-separated structure and induction heating resulted in high initial adhesion and easy disassembly. The phase-separated structure developed in this study forms a sea-island structure with different elastic moduli, enabling a combination of flexibility and adhesive strength. Furthermore, the decrease in bulk elastic modulus during induction heating is thought to have had a significant effect on the development of the disassembly function.

Claims

1. A method for dismantling an adhesive body in which base material A and base material B are joined via an adhesive layer, The adhesive layer has a phase-separated structure, The bonding body includes a heating step of induction heating or microwave heating, The adhesive layer is a cured product of an epoxy resin composition. The aforementioned phase separation structure is formed by the curing of the epoxy resin composition. The epoxy resin composition is An epoxy resin (A) represented by the following general formula (1) with an epoxy equivalent weight of 500 to 10,000 g / equivalent, It contains epoxy resin (B) with an epoxy equivalent of 100 to 300 g / equivalent, Furthermore, the epoxy resin (A) and the epoxy resin (B) together contain 2 to 20 parts by mass of a heterocyclic aromatic compound (C) having a tertiary amino group, in a total of 100 parts by mass. Method for disassembling an adhesive bond. 【Chemistry 1】 [In formula (1), each Ar independently has a structure that is either unsubstituted or has a 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), 【Chemistry 2】 [In equations (2) and (3), Ar is the same as described above.] R1 and R2 are each independently a hydrogen atom, a methyl group, or an ethyl group. R' is a divalent hydrocarbon group with 2 to 12 carbon atoms. R3, R4, R7, and R8 are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group. R5, R6, R9, and R10 are each independently a hydrogen atom or a methyl group. n1 is an integer between 4 and 16. n² is the average value of the repeating units, ranging from 2 to 30. R11 and R12 are each independently a glycidyl ether group or a 2-methylglycidyl ether group. R13 and R14 are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group. R15 and R16 are hydrogen atoms or methyl groups. m1, m2, p1, p2, and q are repeated average values, m1 and m2 are independently between 0 and 25, and m1 + m2 ≥ 1. p1 and p2 are independently between 0 and 5. q is between 0.5 and 5. However, the bonding between X represented by general formula (2) and Y represented by general formula (3) may be random or blocky, and the total number of each structural unit X and Y present in one molecule is m1 and m2, respectively.

2. The method for dismantling an adhesive body according to claim 1, wherein the mass ratio (A):(B) of the epoxy resin (A) to the epoxy resin (B) is 90:10 to 10:

90.

3. The method for dismantling an adhesive according to claim 1, 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.

4. The method for dismantling an adhesive according to claim 1, 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 body according to any one of claims 1 to 4, wherein the epoxy resin composition further comprises thermally expandable particles (D).

6. The method for dismantling an adhesive body according to claim 5, wherein the thermally expandable particles (D) are at least one selected from the group consisting of thermally expandable microcapsules and expanded graphite.

7. The method for dismantling an adhesive body according to claim 5, wherein the proportion of the thermally expandable particles (D) used is within the range of 3 to 40 parts by mass with respect to 100 parts by mass of the total of the epoxy resin (A) and the epoxy resin (B).

8. The epoxy resin composition further comprises a glycidyl ether group-containing compound (E), The glycidyl ether group-containing compound (E) is a compound in which a structural unit V having one or more glycidyl ether groups and a structural unit W different from the structural unit V are linked in a V-W-V manner. A method for disassembling an adhesive according to any one of claims 1 to 4, wherein the structural unit V and the structural unit W are bonded together by a reversible bond formed by a Diels-Alder reaction between a furan structure and a maleimide structure.

9. The method for dismantling an adhesive according to claim 8, wherein the glycidyl ether group-containing compound (E) is a compound represented by the following general formula (4) and having a molecular weight of less than 1000. 【Transformation 3】 [In equation (4), m3 is an integer between 1 and 4. Z １ This is given by the following equation (5), Z ３ The structure is one of the structures represented by the following formula (6), and each of the multiple structures in a single molecule may be the same or different. 【Chemistry 4】 (The aromatic ring in formula (5) may be unsubstituted or substituted, and * represents a bond point. G is a glycidyl group or a 2-methylglycidyl group.) 【Transformation 5】 (In formula (6), R'' is independently a hydrogen atom, a methyl group, or an ethyl group; w1 is an integer from 1 to 30; w2 is the average value of the number of repetitions, from 0.5 to 8; w3 is the average value of the number of repetitions, from 0.5 to 6; and * represents a bond point.)

10. The method for dismantling an adhesive body according to claim 1, wherein the epoxy resin composition further comprises a curing agent (F).

11. The aforementioned phase separation structure consists of resin particles with an average particle diameter of 10 nm to 100 μm and a matrix surrounding them. The method for dismantling an adhesive body according to claim 1, 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).

12. The aforementioned phase separation structure consists of resin particles with an average particle diameter of 10 nm to 100 μm and a matrix surrounding them. The method for dismantling an adhesive body according to claim 1, 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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