Curable resin composition, cured product thereof, and disassemblable adhesive material

Abstract

Provided are: a curable resin composition that obtains a cured product having excellent adhesiveness, flexibility and dismantling properties; a cured product thereof; and a disassemblable adhesive material. A curable resin composition according to the present embodiment contains: an epoxy resin (A) having a specific structure and having an epoxy equivalent weight of 500-10,000 g / eq, an epoxy resin (B) having an epoxy equivalent weight of 100-300 g / eq, a curable functional group-containing compound (C), and thermally expandable particles (D). The curable functional group-containing compound (C) has a specific structure having a reversible bond.

Description

Curable resin composition, cured product thereof, and dismantlable adhesive material

[0001] The present invention relates to a curable resin composition, a cured product, and a dismantlable adhesive material comprising the cured product. This application claims priority to Japanese Patent Application No. 2023-195113, filed on November 16, 2023, the contents of which are incorporated herein by reference.

[0002] Cured products obtained from epoxy resins have excellent heat resistance, mechanical strength, electrical properties, adhesive properties, etc., and are essential materials in various fields such as electrical and electronic applications, paints, and adhesives.

[0003] On the other hand, cured products using thermosetting resins such as epoxy resins have low long-term reliability. For example, when a cured product of an epoxy resin deteriorates due to oxidation, cracks may occur.

[0004] Furthermore, the cured products obtained by curing thermosetting resins such as epoxy resins are insoluble in solvents and infusible even at high temperatures. This makes them difficult to recycle or reuse, and the cured products become waste after use. Therefore, reducing waste and mitigating the burden on the environment has become a challenge.

[0005] Therefore, there is a need to solve the problems of extending the lifespan and reducing waste for cured products made from epoxy resins, etc., and it is thought that giving the cured products easy dismantling properties would be an effective way to solve these problems.

[0006] For example, improving the performance of adhesives for structural materials is essential for reducing the weight of automobiles, airplanes, and other vehicles. On the other hand, achieving high adhesive performance can lead to products that are difficult to recycle, limiting their ease of disassembly and reusability after use. Given the recent rise in environmental awareness, it is also important to develop adhesives that maintain high adhesive performance while allowing for easy peeling after a period of use. Against this background, active development of easily dismantlable adhesives has been underway. While the thermal melting of thermoplastic resins is generally utilized, in recent years, technologies have been proposed in which thermosetting resins are premixed with thermally expandable materials or thermally decomposable compounds, and then the adhesive strength is reduced and the adhesive is peeled off by applying mainly thermal energy after use (see, for example, Patent Documents 1 and 2).

[0007] JP 2003-286464 A JP 2013-256557 A

[0008] However, the technology of Patent Document 1 essentially uses a conventional curable resin composition as an adhesive. Therefore, foaming due to the thermally expandable material in the cured product (adhesive layer) is difficult to fully manifest. As a result, peelability may be insufficient, or the adhesive layer may be difficult to remove cleanly due to its brittleness. Furthermore, the technology of Patent Document 2 pre-contains a thermally decomposable compound. This requires precise control of the heating temperature during the curing reaction. This creates a complex usage problem. Particularly when using metal substrates with high thermal conductivity, there is a possibility that the adhesive may be overheated in unexpected locations, resulting in problems. Furthermore, the adhesive must be discarded after disassembly, and although the substrate to be adhered is recyclable, there is a problem of insufficient recyclability overall. Therefore, the present invention aims to provide a curable resin composition that is a curable resin but has excellent adhesive properties, flexibility, and dismantlability when cured, a cured product of the cured product, and a dismantlable adhesive material comprising the cured product.

[0009] As a result of extensive research, the present inventors discovered that the above-mentioned problems can be solved by using a curable functional group-containing compound having a specific structure and an epoxy resin having a specific structure, and by blending thermally expandable particles into a resin composition, and thus completed the invention.

[0010] That is, the present invention encompasses the following aspects: [1] A curable resin composition comprising: an epoxy resin (A) represented by the following general formula (1) and having an epoxy equivalent of 500 to 10,000 g / eq; an epoxy resin (B) having an epoxy equivalent of 100 to 300 g / eq; a curable functional group-containing compound (C) represented by either of the following general formulas (4-1) or (4-2); and thermally expandable particles (D). [In formula (1), each Ar independently represents a structure having an unsubstituted or substituted aromatic ring, X represents a structural unit represented by the following general formula (2), and Y represents a structural unit represented by the following general formula (3): [In formulas (2) and (3), Ar is the same as above, and R １ , R ２ are each independently a hydrogen atom, a methyl group, or an ethyl group; R' is a divalent hydrocarbon group having 2 to 12 carbon atoms; R ３ , R ４ , R ７ , R ８ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R ５ , R ６ , R ９ , R １０ are each independently a hydrogen atom or a methyl group, n1 is an integer of 4 to 16, and n2 is the average number of repeating units of 2 to 30.] R １１ , R １２ are each independently a glycidyl ether group or a 2-methylglycidyl ether group, and R １３ , R １４ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R １５ , R １６ represents a hydrogen atom or a methyl group, m1, m2, p1, p2, and q represent the average value of the repeating units, m1 and m2 each independently represent 0 to 25 and m1+m2≧1, p1 and p2 each independently represent 0 to 5, and q represents 0.5 to 5. However, the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total number of structural units X and Y present in one molecule represents m1 and m2, respectively. [The furan-derived structures in formulas (4-1) and (4-2) may have a halogen atom, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amide group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group as a substituent. n ａ , n b is the average number of repeats, and each independently is 0 to 10. m is an integer of 1 to 4. Z １ is the following formula (5), Z ２is one of the structures represented by the following formulas (6A) and (6B), and Z ３ is any of the structures represented by the following formulas (7-1) to (7-3), and a plurality of such structures in one molecule may be the same or different. [The aromatic ring in formula (5) may be substituted or unsubstituted, * represents a bonding point, Fg is a curable functional group, and -Fg on the naphthalene ring in the formula indicates that it may be bonded to any position.] In formulas (6A) and (6B), each Ar independently represents a structure having an unsubstituted or substituted aromatic ring, and R １ , R ２ are each independently a hydrogen atom, a methyl group, or an ethyl group, R is a hydrogen atom or a methyl group, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms, n1 is an integer from 4 to 16, n2 is the average number of repeating units and is 2 to 30, k1 is the average number of repeating units and is in the range of 0.5 to 5, p1 and p2 are each independently 0 to 5, X is a structural unit represented by the following formula (6-1), and Y is a structural unit represented by the following formula (6-2), [In formula (6-1) (6-2), Ar, R, R １ , R ２ , R', n1, and n2 are the same as above.] m1 and m2 are the average values ​​of the repeating units, each independently ranging from 0 to 25, and m1+m2≧1. However, the structural unit X represented by formula (6-1) and the structural unit Y represented by formula (6-2) may be bonded randomly or in blocks, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.] [In formulas (7-1) to (7-3), n3 and n5 are the average values ​​of the number of repeats, each of which is 0.5 to 10, n4 is an integer of 1 to 16, and each R" is independently a hydrogen atom, a methyl group, or an ethyl group.] [2] The curable resin composition according to [1], wherein the curable functional group-containing compound (C) is a hydroxyl group-containing compound or an amine group-containing compound. [3] The curable resin composition according to [1] or [2], wherein the concentration of reversible bonds in the curable functional group-containing compound (C) relative to the total mass of the curable components in the curable resin composition is 0.10 mmol / g or more. [4] The curable resin composition according to any one of [1] to [3], further comprising a curing agent for epoxy resins other than the curable functional group-containing compound (C). [5] The curable resin composition according to any one of [1] to [4], wherein the mass ratio (A):(B) of the epoxy resin (A) to the epoxy resin (B) is 90:10 to 10:90. [6] The curable resin composition according to any one of [1] to [5], wherein the thermally expandable particles (D) are at least one selected from the group consisting of thermally expandable microcapsules and expandable graphite. [7] The curable resin composition according to any one of [1] to [6], wherein the proportion of the thermally expandable particles (D) used is in the range of 3 to 40 parts by mass per 100 parts by mass of the epoxy resin (A) and the epoxy resin (B) combined. [8] A cured product obtained by curing the curable resin composition according to any one of [1] to [6]. [9] A laminate having a substrate and a layer containing the cured product according to [8].

[10] A heat-resistant component containing the cured product according to [8].

[11] A dismantlable adhesive material containing the curable resin composition according to any one of [1] to [6].

[12] A dismantling method using the dismantling adhesive material according to

[11] , comprising: a bonding step of attaching the dismantling adhesive material to the surface of an adherend and bonding it to the adherend; a curing step of curing the dismantling adhesive material to obtain a cured product; a heat treatment step of subjecting the cured product to a heat treatment to thermally dissociate a reversible bond contained in either of the general formulas (4-1) and (4-2) derived from the curable functional group-containing compound (C) and expand the heat-expandable particles (D); and a dismantling step of dismantling the adherend and the cured product.

[13] The dismantling method according to

[12] , further comprising, after the heat treatment step and before the dismantling step, a cooling step of cooling the heat-treated hardened product to room temperature.

[0011] According to the present invention, it is possible to provide a curable resin composition that has excellent adhesiveness, flexibility, and dismantling properties when cured.

[0012] Next, the embodiments for carrying out the present invention will be described in detail. It should be understood that the present invention is not limited to the following embodiments, and that appropriate design changes, improvements, etc. may be made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.

[0013] (Curable Resin Composition) A curable resin composition according to one embodiment of the present invention (the present embodiment) is a curable resin composition comprising an epoxy resin (A) having an epoxy equivalent of 500 to 10,000 g / eq and represented by the general formula (1) above, an epoxy resin (B) having an epoxy equivalent of 100 to 300 g / eq, a curable functional group-containing compound (C) represented by either the general formula (4-1) or (4-2) above, and thermally expandable particles (D). In the curable resin composition of the present embodiment, the curable functional group-containing compound (C) is preferably a hydroxyl group-containing compound or an amine group-containing compound. The curable resin composition of the present embodiment may optionally contain an epoxy resin other than the epoxy resin (A), the epoxy resin (B), and the curable functional group-containing compound (C) according to the present embodiment. Furthermore, the curable resin composition of the present embodiment may contain, as necessary, a curing agent for an epoxy resin that does not belong to the curable functional group-containing compound (C), a curing accelerator, other thermosetting resins or thermoplastic resins, a non-halogen flame retardant, a filler that does not belong to the thermally expandable particles (D) of the present embodiment, a dispersion medium, etc. Each component will be described in detail below.

[0014] [Epoxy Resin (A)] The epoxy resin (A) contained in the curable resin composition of the present embodiment is an epoxy resin represented by the following general formula (1) and having an epoxy equivalent of 500 to 10,000 g / eq. [In formula (1), each Ar independently represents a structure having an unsubstituted or substituted aromatic ring, X represents a structural unit represented by the following general formula (2), and Y represents a structural unit represented by the following general formula (3): [In formulas (2) and (3), Ar is the same as above, and R １ , R ２ are each independently a hydrogen atom, a methyl group, or an ethyl group; R' is a divalent hydrocarbon group having 2 to 12 carbon atoms; R ３ , R ４ , R ７ , R ８ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R ５ , R ６ , R ９ , R １０ are each independently a hydrogen atom or a methyl group, n1 is an integer of 4 to 16, and n2 is the average number of repeating units of 2 to 30.] R １１ , R １２ are each independently a glycidyl ether group or a 2-methylglycidyl ether group, and R １３ , R １４ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R １５ , R １６ represents a hydrogen atom or a methyl group, m1, m2, p1, p2, and q represent the average value of the repeating units, m1 and m2 each independently represent 0 to 25 and m1+m2≧1, p1 and p2 each independently represent 0 to 5, and q represents 0.5 to 5. However, the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total number of structural units X and Y present in one molecule represents m1 and m2, respectively.

[0015] The above structure contains the structural unit X represented by general formula (2) and / or the structural unit Y represented by general formula (3), and the presence of the alkylene chain or polyether chain in each structural unit makes it possible to impart high flexibility to the cured product. In particular, the flexibility provided by the alkylene chain enables the epoxy resin (A) to follow the thermal expansion of the substrate when used as an adhesive, and the polyether chain has the effect of lowering the viscosity of the epoxy resin (A) itself, thereby contributing to improved coatability and processability as a curable resin composition.

[0016] The epoxy resin (A) may have each of the structural units X and Y singly, or may have both the structural units X and Y in one molecule. In this case, X and Y may be bonded in a block bond or a random bond, and the total number of the structural units X and Y contained in one molecule is m1 and m2, respectively.

[0017] Ar in general formula (1) representing the epoxy resin (A), Ar in general formula (2) representing the structural unit X, and Ar in general formula (3) representing the structural unit Y all have a structure having an unsubstituted or substituted aromatic ring. The aromatic ring is not particularly limited, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and a fluorene ring.

[0018] Among these, Ar preferably has any of the structures represented by the following structural formula (ar).

[0019] (The aromatic ring in formula (ar) may be substituted or unsubstituted, and * represents the point of attachment.)

[0020] Further, structures represented by the following formulas are also included as Ar.

[0021] (wherein the aromatic ring may be substituted or unsubstituted, n3=1 to 4, and * represents a point of attachment.)

[0022] The aromatic ring of Ar may be substituted or unsubstituted. When Ar has a substituent, the substituent is preferably an alkyl group, a halogen atom, a glycidyl ether group, a 2-methylglycidyl ether group, or the like. Preferably, Ar is unsubstituted, or an alkyl group, a glycidyl ether group, or a 2-methylglycidyl ether group. The number of substituents per aromatic ring is preferably two or less, more preferably one or less, and particularly preferably unsubstituted.

[0023] The following structures are particularly preferred for Ar: * represents a bonding point.

[0024]

[0025] Particularly preferred structures for Ar having a substituent include the following structures: * represents a bonding point.

[0026] R is a hydrogen atom or a methyl group.

[0027] In the structural unit X represented by the general formula (2), the repeating unit n1 is an integer of 4 to 16. When n1 is 4 or more, the adhesive strength is improved and the deformation mode of the cured product is elastic deformation. Furthermore, when n1 is 16 or less, a decrease in crosslink density can be suppressed. It is preferably 4 to 15, and more preferably 6 to 12.

[0028] In the structural unit X represented by the general formula (2), R １ , R ２ are each independently a hydrogen atom, a methyl group, or an ethyl group, and R ３ , R ４ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R ５ , R ６ are each independently a hydrogen atom or a methyl group.

[0029] Among these, R ３ , R ４ is preferably a hydroxyl group, and R ５ , R ６ is preferably a hydrogen atom.

[0030] In the structural unit Y represented by the general formula (3), n2 is the average value of the repeating units and is 2 to 30. This range is preferred from the viewpoint of achieving a good balance between the viscosity of the epoxy resin (A) and the crosslink density of the resulting cured product. It is preferably 2 to 25, and more preferably 4 to 20.

[0031] In the structural unit Y represented by the general formula (3), R' is a divalent hydrocarbon group having 2 to 12 carbon atoms. Within this range, the adhesive strength is improved and the deformation mode of the cured product is elastic. Preferably, R' is a divalent hydrocarbon group having 2 to 6 carbon atoms.

[0032] The divalent hydrocarbon group is not particularly limited, and examples thereof include a linear or branched alkylene group, an alkenylene group, an alkynylene group, a cycloalkylene group, an arylene group, and an aralkylene group (a divalent group having an alkylene group and an arylene group).

[0033] Examples of alkylene groups include methylene, ethylene, propylene, butylene, pentylene, hexylene, trimethylene, tetramethylene, pentamethylene, and hexamethylene groups. Examples of alkenylene groups include vinylene, 1-methylvinylene, propenylene, butenylene, and pentenylene groups. Examples of alkynylene groups include ethynylene, propynylene, butynylene, pentynylene, and hexynylene groups. Examples of cycloalkylene groups include cyclopropylene, cyclobutylene, cyclopentylene, and cyclohexylene groups. Examples of arylene groups include phenylene, tolylene, xylylene, and naphthylene groups.

[0034] Among these, ethylene, propylene and tetramethylene groups are preferred from the viewpoint of the balance between the availability of raw materials, the viscosity of the resulting epoxy resin (A), and the flexibility of the cured product.

[0035] In the structural unit Y represented by the general formula (3), R ７ , R ８ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R９ , R １０ are each independently a hydrogen atom or a methyl group. ７ , R ８ is preferably a hydroxyl group, and R ９ , R １０ is preferably a hydrogen atom.

[0036] As described above, the epoxy resin (A) used in this embodiment is represented by the general formula (1). In the general formula (1), m1 and m2 are the average values ​​of the repeating numbers of the structural unit X and the structural unit Y, respectively, and are each independently 0 to 25, and m1+m2≧1.

[0037] In addition, R in the general formula (1) １１ , R １２ are each independently a glycidyl ether group or a 2-methylglycidyl ether group, and R １３ , R １４ are each independently a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group, and R １５ , R １６ is a hydrogen atom or a methyl group, p1, p2, and q are the average values ​​of the repeating groups, p1 and p2 are each independently 0 to 5, and q is 0.5 to 5. １１ , R １２ is preferably a glycidyl ether group, and R １３ , R １４ is preferably a hydroxyl group, and R １５ , R １６ is preferably a hydrogen atom. Furthermore, p1 and p2 are preferably 0 to 2, and q is preferably 0.5 to 2.

[0038] Furthermore, the epoxy equivalent of the epoxy resin (A) used in this embodiment is 500 to 10,000 g / eq. This range ensures an excellent balance between flexibility and crosslink density of the resulting cured product. From the viewpoint of ease of handling and a better balance between flexibility and crosslink density, the range of 600 to 8,000 g / eq is preferred, and the range of 800 to 5,000 g / eq is more preferred.

[0039] Among the epoxy resins (A) in this embodiment, examples of resins having both the structural unit X and the structural unit Y in one molecule include resins having the following structural formulas.

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052] In the structural formulas (A-1) to (A-12), ran represents a random bond, G represents a glycidyl group, R' represents a divalent hydrocarbon group having 2 to 12 carbon atoms, n1 is an integer from 4 to 16, n2 represents the average value of the repeating units and is 2 to 30, m1, m2, p1, p2, and q represent the average value of the repeating units, m1 and m2 each independently represent 0.5 to 25, p1 and p2 each independently represent 0 to 5, and q represents 0.5 to 5. However, the repeating units present in the repeating units may be the same or different from each other.

[0053] Among the above structural formulas, it is most 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 obtaining a cured product with a better balance of physical properties.

[0054] Among the epoxy resins (A), examples of the epoxy resins having the structural unit X include resins represented by the following structural formulas.

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067] In the above structural formulas (A-13) to (A-24), G is a glycidyl group, n1 is an integer of 4 to 16, m1, p1, p2, and q are average values ​​of the repeating units, m1 is 0.5 to 25, p1 and p2 are each independently 0 to 5, and q is 0.5 to 5. However, the repeating units present in the repeating units may be the same or different from each other.

[0068] Among the above structural formulas, 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 provide a more excellent balance of physical properties of the resulting cured product.

[0069] Among the epoxy resins (A), examples of the epoxy resins having the structural unit Y include resins represented by the following structural formulas.

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082] In the structural formulas (A-25) to (A-36), G is a glycidyl group, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms, n2 is the average value of the repeating units and is 2 to 30, m2, p1, p2, and q are the average values ​​of the repeating units, m2 is 0.5 to 25, p1 and p2 are each independently 0 to 5, and q is 0.5 to 5. However, the repeating units present in the repeating units may be the same or different.

[0083] Among the above structural formulas, it is most 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 provide a more excellent balance of physical properties of the resulting cured product.

[0084] <Method for Producing Epoxy Resin (A)> The method for producing the epoxy resin (A) according to the present embodiment is not particularly limited, but for example, a method in which a diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain is reacted with an aromatic hydroxy compound (a2) in a molar ratio (a1) / (a2) of 1 / 1.01 to 1 / 5.0 to obtain a hydroxy compound (corresponding to a precursor or intermediate of the epoxy resin (A)), and then the hydroxy compound is reacted with epihalohydrin (a3) ​​is preferred from the viewpoints of ease of raw material availability and reaction.

[0085] The product obtained by the reaction of the diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain with an aromatic hydroxy compound (a2) to obtain a hydroxy compound may contain unreacted aromatic hydroxy compound (a2). During the synthesis of the epoxy resin (A) used in this embodiment, the product may be directly subjected to the reaction with epihalohydrin (a3), which is the next step, or the unreacted aromatic hydroxy compound (a2) may be removed. However, from the viewpoint of the balance between toughness and flexibility of the cured product obtained from the curable resin composition of this embodiment containing the resulting epoxy resin (A), the presence rate of unreacted aromatic hydroxy compound (a2) in the hydroxy compound to be subjected to the next step is preferably in the range of 0.1 to 30% by mass. The method for removing the unreacted aromatic hydroxy compound (a2) is not particularly limited, and various methods can be used. Examples include column chromatography separation, which utilizes differences in polarity; fractional distillation, which utilizes differences in boiling points; and alkaline aqueous extraction, which utilizes differences in solubility in alkaline water. Among these, the alkaline aqueous extraction method is preferred in terms of efficiency because it does not involve thermal alteration, and the organic solvent used to dissolve the target substance can be any organic solvent that is immiscible with water, such as toluene or methyl isobutyl ketone. In addition, methyl isobutyl ketone is particularly preferred from the viewpoint of solubility with the target substance.

[0086] The diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain is not particularly limited. For example, diglycidyl ethers having an alkylene chain 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, 1,13-tridecanediol 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 organic chlorine impurities produced during the glycidyl etherification of a hydroxy compound, or may contain organic chlorine such as 1-chloromethyl-2-glycidyl ether (chloromethyl form) represented by the following structure. These diglycidyl ethers may be used alone or in combination of two or more types.

[0087]

[0088] Among these, 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, because they provide an excellent balance between flexibility and heat resistance of the resulting cured product.

[0089] Furthermore, by simultaneously reacting the above-mentioned diglycidyl ether having an alkylene chain and the diglycidyl ether having a polyether chain with an aromatic hydroxy compound (a2), a hydroxy compound having both the structural unit X and the structural unit Y can be obtained, and by further reacting this with epihalohydrin (a3), an epoxy resin (A) having both the structural unit X and the structural unit Y can be obtained.

[0090] The aromatic hydroxy compound (a2) is not particularly limited, and examples thereof include dihydroxybenzenes such as hydroquinone, resorcinol, and catechol; trihydroxybenzenes such as pyrogallol, 1,2,4-trihydroxybenzene, and 1,3,5-trihydroxybenzene; triphenylmethane-type phenols such as 4,4',4"-trihydroxytriphenylmethane; dihydroxynaphthalenes such as 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene; tetrafunctional phenols such as 1,1'-methylenebis-(2,7-naphthalenediol), 1,1'-binaphthalene-2,2',7,7'-tetraol, and 1,1'-oxybis-(2,7-naphthalenediol) obtained by coupling reaction of dihydroxynaphthalenes; bisphenols such as bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 1,1-bis(4-hydroxyphenyl)-1-phenylethane, and bis(4-hydroxyphenyl)sulfone, 2,2'-biphenol, 4,4'-biphenol, (1,1'-biphenyl)-3,4-diol, 3,3'-dimethyl-(1,1'-biphenyl)-4,4'-diol, 3-methyl-(1,1'-biphenyl)-4,4'-diol, 3,3',5,5'-tetramethylbiphenyl-2,2'-diol, 3,3',5,5'-tetramethylbiphenyl-4,4'-diol, 5-methyl-(1,1'-biphenyl)-3,4'diol, 3'-methyl-(1,1'-biphenyl)-3,4'diol, 4'-methyl-(1,1'-biphenyl)-3,Examples of suitable phenolic compounds include biphenols such as 4'-diol, alicyclic structure-containing phenols such as polyadducts of phenol and dicyclopentadiene and polyadducts of phenol and terpene compounds, naphthols such as bis(2-hydroxy-1-naphthyl)methane and bis(2-hydroxy-1-naphthyl)propane, and so-called Xylok-type phenolic resins, which are condensation reaction products of phenol and phenylene dimethyl chloride or biphenylene dimethyl chloride. These may be used alone or in combination of two or more. Further examples include compounds in which the aromatic nucleus of each of the above compounds is substituted with a methyl group, t-butyl group, or halogen atom. The alicyclic structure-containing phenols and the Xylok-type phenolic resins may contain not only bifunctional components but also trifunctional or higher functional components. These compounds may be used as is in the present invention, or the bifunctional components may be isolated and used after purification using a column or other purification process.

[0091] Among these, bisphenols are preferred because they provide an excellent balance between flexibility and toughness when cured, and bis(4-hydroxyphenyl)methane and 2,2-bis(4-hydroxyphenyl)propane are particularly preferred because of their outstanding toughness-imparting properties. Furthermore, when emphasis is placed on the curability and heat resistance of the cured product, dihydroxynaphthalenes are preferred, and 2,7-dihydroxynaphthalene is particularly preferred because of its outstanding fast-curing properties. Furthermore, when emphasis is placed on the moisture resistance of the cured product, it is preferable to use a compound containing an alicyclic structure.

[0092] From the viewpoint of reaction efficiency, the reaction ratio of the diglycidyl ether (a1) of the dihydroxy compound having an alkylene chain or a polyether chain to the aromatic hydroxy compound (a2) is preferably (a1) / (a2) from 1 / 1.01 to 1 / 5.0 (molar ratio), and more preferably (a1) / (a2) from 1 / 1.02 to 1 / 3.0 (molar ratio).

[0093] The reaction between the diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a 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 DMP-30, DMAP, tetramethylammonium, tetraethylammonium, tetrabutylammonium, and benzyltributylammonium; quaternary ammonium salts such as chlorides, bromides, and iodides such as tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, and benzyltributylphosphonium; tertiary amines such as triethylamine, N,N-dimethylbenzylamine, 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. Two or more of these catalysts may be used in combination. Among these, sodium hydroxide, potassium hydroxide, triphenylphosphine, and DMP-30 are preferred because the reaction proceeds rapidly and the amount of impurities is highly reduced. 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 aromatic hydroxyl groups in the aromatic hydroxy compound (a2). The form of these catalysts is also not particularly limited, and they may be used in the form of an aqueous solution or in the form of a solid.

[0094] The reaction between the diglycidyl ether (a1) of a dihydroxy compound having an alkylene chain or a polyether chain and the aromatic hydroxy compound (a2) can be carried out in the absence of a solvent or in the presence of an organic solvent. Examples of organic solvents that can be used include methyl cellosolve, ethyl cellosolve, toluene, xylene, methyl isobutyl ketone, dimethyl sulfoxide, propyl alcohol, and butyl alcohol. The amount of organic solvent used is typically 50 to 300% by mass, preferably 100 to 250% by mass, based on the total mass of the raw materials charged. These organic solvents can be used alone or in combination. The use of no solvent is preferred to rapidly carry out the reaction, while the use of dimethyl sulfoxide is preferred to reduce impurities in the final product.

[0095] The reaction temperature when carrying out the reaction is typically 50 to 180°C, and the reaction time is typically 1 to 30 hours. A reaction temperature of 100 to 160°C is preferred from the viewpoint of reducing impurities in the final product. Furthermore, if the resulting compound exhibits significant coloration, an antioxidant or a reducing agent may be added to suppress this. The antioxidant is not particularly limited, but examples thereof include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite ester compounds containing a trivalent phosphorus atom. The reducing agent is not particularly limited, but examples thereof include hypophosphorous acid, phosphorous acid, thiosulfuric acid, sulfurous acid, hydrosulfite, or salts thereof.

[0096] After completion of the reaction, the reaction mixture may be neutralized or washed with water until the pH reaches 3 to 7, preferably 5 to 7. The neutralization and washing may be carried out in a conventional manner. For example, when a basic catalyst is used, an acidic substance such as hydrochloric acid, sodium dihydrogen phosphate, p-toluenesulfonic acid, or oxalic acid may be used as a neutralizing agent. After neutralization or washing, the solvent may be distilled off under reduced pressure and heating, if necessary, and the product may be concentrated to obtain a hydroxy compound.

[0097] By using the glycidyl ether having an alkylene chain and the glycidyl ether having a polyether chain in combination, a hydroxy compound having both the structural unit X and the structural unit Y can be obtained. In this case, preferred structures include, for example, compounds represented by the following structural formula:

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110] In each of the structural formulas above, ran represents a random bond, R' represents a divalent hydrocarbon group having 2 to 12 carbon atoms, n1 represents an integer from 4 to 16, n2 represents the average value of the repeating units and is 2 to 30, and m1 and m2 represent the average value of the repeating units and are each independently 0.5 to 25. However, each repeating unit present in the repeating unit may be the same or different.

[0111] Furthermore, by using the glycidyl ether having an alkylene chain as a raw material, a hydroxy compound having the structural unit X can be obtained. In this case, preferred structures include, for example, compounds represented by the following structural formula:

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123]

[0124] In each of the structural formulas above, n1 is an integer of 4 to 16, and m1 is the average value of the number of repeats, which is 0.5 to 25.

[0125] Furthermore, by using the glycidyl ether having the polyether chain as a raw material, a hydroxy compound having the structural unit Y can be obtained. In this case, preferred structures include, for example, compounds represented by the following structural formula:

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138] In each of the structural formulas above, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms, n2 is the average number of repeating units that is 2 to 30, and m2 is the average number of repeating units that is 0.5 to 25. However, each repeating unit present in the repeating unit may be the same or different.

[0139] In the method for producing the epoxy resin (A), the method for the glycidyl etherification reaction of the precursor (intermediate) hydroxy compound obtained above is not particularly limited, and examples thereof include a method of reacting a phenolic hydroxyl group with epihalohydrin, a method of olefinating the phenolic hydroxyl group and then oxidizing the carbon-carbon double bond of the olefin with an oxidizing agent, etc. Among these, the method using epihalohydrin (a3) ​​is preferred in terms of ease of raw material availability and reaction.

[0140] An example of a method using epihalohydrin (a3) ​​is to add 0.3 to 100 moles of epihalohydrin (a3) ​​per mole of aromatic hydroxyl groups of the hydroxy compound obtained above, and then react this mixture at a temperature of 20 to 120°C for 0.5 to 10 hours while adding, all at once or gradually, 0.9 to 2.0 moles of a basic catalyst per mole of aromatic hydroxyl groups of the hydroxy compound. The greater the excess amount of epihalohydrin (a3) ​​added, the closer the resulting epoxy resin will be to its theoretical structure, and the more effectively it can suppress the formation of secondary hydroxyl groups resulting from the reaction of unreacted aromatic hydroxyl groups with epoxy groups. From this perspective, a range of 2.5 to 100 equivalents is preferred. This basic catalyst may be a solid or may be used in the form of an aqueous solution. When an aqueous solution is used, it may be continuously added, and at the same time, water and epihalohydrin (a3) ​​may be continuously distilled from the reaction mixture under reduced pressure or under normal pressure, followed by liquid separation to remove water and continuously return epihalohydrin (a3) ​​to the reaction mixture.

[0141] In industrial production, all of the charged epihalohydrin (a3) ​​is freshly used in the first batch of epoxy resin production, but from the next batch onwards, it is preferred to use a combination of epihalohydrin (a3) ​​recovered from the crude reaction product and fresh epihalohydrin (a3) ​​equivalent to the amount consumed and lost in the reaction. The epihalohydrin (a3) ​​used in this case is not particularly limited, and examples include epichlorohydrin and epibromohydrin. Among these, epichlorohydrin is preferred because of its easy availability.

[0142] The basic catalyst is not particularly limited, and examples thereof include alkaline earth metal hydroxides, alkali metal carbonates, and alkali metal hydroxides. In particular, alkali metal hydroxides are preferred because of their excellent catalytic activity in the epoxy resin synthesis reaction, and examples thereof include sodium hydroxide and potassium hydroxide. When used, these alkali metal hydroxides may be used in the form of an aqueous solution of about 10 to 55 mass %, or may be used in solid form.

[0143] Furthermore, the reaction rate in the synthesis of the epoxy resin can be increased by using an organic solvent in combination. Examples of such organic solvents include, but are not limited to, ketones such as acetone and methyl ethyl ketone; alcohols such as methanol, ethanol, 1-propyl alcohol, isopropyl alcohol, 1-butanol, secondary butanol, and tertiary butanol; cellosolves such as methyl cellosolve and ethyl cellosolve; ethers such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, and diethoxyethane; and aprotic polar solvents such as acetonitrile, dimethyl sulfoxide, and dimethylformamide. These organic solvents may be used alone, or two or more may be used in combination as appropriate to adjust the polarity.

[0144] The reaction product of these glycidylation reactions is washed with water, and then the unreacted epihalohydrin (a3) ​​and the organic solvent used are removed by distillation under heating and reduced pressure. Furthermore, to obtain an epoxy resin with even less hydrolyzable halogen, the resulting epoxy resin can be dissolved again in an organic solvent such as toluene, methyl isobutyl ketone, or methyl ethyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide can be added to further carry out the reaction. In this case, a phase transfer catalyst such as a quaternary ammonium salt or a crown ether may be present in order to improve the reaction rate.

[0145] When a phase transfer catalyst is used, the amount thereof is preferably in the range of 0.1 to 3.0% by mass based on the epoxy resin used. After completion of the reaction, the salt formed is removed by filtration, washing with water, or the like, and the solvent, such as toluene or methyl isobutyl ketone, is distilled off under heating and reduced pressure to obtain a high-purity epoxy resin.

[0146] [Epoxy resin (B)]

[0147] The epoxy resin (B) contained in the epoxy resin of this embodiment may have an epoxy equivalent in the range of 100 to 300 g / eq, and its structure is not limited. Examples thereof include liquid epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD ​​type epoxy resins, polyhydroxybenzene type epoxy resins, polyhydroxynaphthalene type epoxy resins, biphenyl type epoxy resins, and tetramethylbiphenyl type epoxy resins; brominated epoxy resins such as brominated phenol novolac type epoxy resins; solid bisphenol A type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins; and dicyclopentasiloxane type epoxy resins. Examples of such epoxy resins include anthradiene-phenol addition reaction type epoxy resins, phenol aralkyl type epoxy resins, phenylene ether type epoxy resins, naphthylene ether type epoxy resins, naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins, aromatic hydrocarbon formaldehyde resin-modified phenolic resin type epoxy resins, and biphenyl-modified novolac type epoxy resins. These may be used alone or in combination of two or more types, and it is preferable to select and use various types depending on the intended use, the physical properties of the cured product, etc.

[0148] Among these, it is preferable to use liquid epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD ​​type epoxy resins, polyhydroxybenzene type epoxy resins, polyhydroxynaphthalene type epoxy resins, biphenyl type epoxy resins, and tetramethylbiphenyl type epoxy resins, and it is particularly preferable to use epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, and bisphenol AD ​​type epoxy resins, and it is particularly preferable to use epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, and bisphenol AD ​​type epoxy resins, and the like, which have an epoxy equivalent of 100 to 300 g / eq.

[0149] In the present embodiment, the ratio of the epoxy resin (A) to the epoxy resin (B) used is not particularly limited, but from the viewpoint of facilitating phase separation in the cured product, the mass ratio (A):(B) of the epoxy resin (A) to the epoxy resin (B) is 90:10 to 10:90, preferably 80:20 to 20:80, and particularly preferably 70:30 to 30:70. Phase separation in the cured product results in a sea-island structure, which allows the cured product to achieve both good adhesion and stress relaxation ability, exhibits high adhesive strength over a particularly wide temperature range, and has the effect of reducing the mold shrinkage rate before and after heat curing of the resin composition.

[0150] [Curable Functional Group-Containing Compound (C)] The curable functional group-containing compound (C) contained in the curable resin composition of the present embodiment is a curable functional group-containing compound (C) represented by any one of the following general formulas (4-1) and (4-2). [The furan-derived structures in formulas (4-1) and (4-2) may have a halogen atom, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amide group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group as a substituent. n ａ , n b is the average number of repeats, and each independently is 0 to 10. m is an integer of 1 to 4. Z １ is the following formula (5), Z ２ are represented by the following formulas (6A) and (6B), Z ３ is any of the structures represented by the following formulas (7-1) to (7-3), and a plurality of such structures in one molecule may be the same or different. [The aromatic ring in formula (5) may be substituted or unsubstituted, * represents a bonding point, Fg is a curable functional group, and -Fg on the naphthalene ring in the formula indicates that it may be bonded to any position.] In formulas (6A) and (6B), each Ar independently represents a structure having an unsubstituted or substituted aromatic ring, and R １ , R ２are each independently a hydrogen atom, a methyl group, or an ethyl group, R is a hydrogen atom or a methyl group, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms, n1 is an integer from 4 to 16, n2 is the average number of repeating units and is 2 to 30, k1 is the average number of repeating units and is in the range of 0.5 to 5, p1 and p2 are each independently 0 to 5, X is a structural unit represented by the following formula (6-1), and Y is a structural unit represented by the following formula (6-2), [In formula (6-1) (6-2), Ar, R, R １ , R ２ , R', n1, and n2 are the same as above.] m1 and m2 are the average values ​​of the repeating units, each independently ranging from 0 to 25, and m1+m2≧1. However, the structural unit X represented by formula (6-1) and the structural unit Y represented by formula (6-2) may be bonded randomly or in blocks, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.] [In formulas (7-1) to (7-3), n3 and n5 are the average numbers of repeating units, each of which is 0.5 to 10, n4 is an integer of 1 to 16, and each R″ is independently a hydrogen atom, a methyl group, or an ethyl group.]

[0151] The curable functional group-containing compound (C) contained in the curable resin composition of this embodiment is characterized by being bonded by a reversible bond due to a Diels-Alder reaction between a furan structure and a maleimide structure.

[0152] By having such a structure, the curable functional group-containing compound (C) is incorporated into a crosslinked structure by a curing reaction based on the curable functional group. On the other hand, since the cured product has reversibility, it has high molecular mobility even in the cured product. Therefore, when the cured product is exposed to high temperatures or subjected to impact, cracks occur, or is crushed, the reversible bond is easily broken, resulting in easy disassembly. On the other hand, the reversible bond reversibly reforms in low temperature ranges, including room temperature, resulting in excellent adhesive properties.

[0153] To introduce the furan-based Diels-Alder addition structure into a compound, a furan having a reactive functional group on the ring and a maleimide having a reactive functional group are used. Specific reversible bond moiety structures can be represented by the following chemical formula. Reversible bonds can be introduced into a compound by bonding with other structural units based on the R moiety in the following formula in the maleimide-derived structure or various reactive functional groups on the ring of the furan-derived structure.

[0154]

[0155] In the Diels-Alder reaction, a conjugated diene and a parent diene undergo an addition reaction to form a six-membered ring. Because the Diels-Alder reaction is an equilibrium reaction, a retro-Diels-Alder reaction occurs at a certain temperature, resulting in dissociation (decrosslinking). When mechanical energy such as scratching or external force is applied to the resulting cured product, the C-C bond of the Diels-Alder reaction unit is preferentially cleaved because the bond energy of the C-C bond is lower than that of a normal covalent bond. This results in the cured product being easily dismantled. Furthermore, in the temperature range lower than the dissociation temperature, the equilibrium of the C-C bond of the Diels-Alder reaction unit shifts toward the bond, thereby again forming an adduct (Diels-Alder reaction unit).

[0156] In the reversible bond formed by the Diels-Alder reaction, the reversible bond formed by the Diels-Alder reaction with the furan structure and the maleimide structure undergoes a Retro-Diels-Alder reaction and dissociates (decrosslinks) at around 120° C. Therefore, the heating temperature required for the cured product to exhibit easy dismantling properties can be reduced, and the cured product has excellent easy dismantling properties for applications where high-temperature heating is not suitable.

[0157] The average molecular weight (Mw) of the curable functional group-containing compound (C) is not particularly limited, but from the viewpoint of achieving both mechanical strength, flexibility, and ease of dismantling when formed into a cured product, it is preferably 500 or more and preferably 50,000 or less. Furthermore, when there are multiple reversible bonds other than between A and B, for example, in the structural unit B, it is more preferable that the molecular weight per reversible bond is in the range of 300 to 10,000 from the viewpoint of ease of dismantling and remoldability of the cured product.

[0158] The curable functional group-containing compound (C) represented by any one of the general formulas (4-1) and (4-2) has a reversible bond formed by a furan structure and a maleimide structure at the end of the molecule. The terminal maleimide structure in the general formula (4-1) and the terminal furan structure in the general formula (4-2) are each provided with a Z structure represented by any one of the general formulas (5). １ This curable functional group contributes to the curing reaction in the curable resin composition described below. m is the number of Z1 in the furan-derived structure and is an integer of 1 to 4. From the viewpoints of industrial availability of raw materials, ease of control of the curing reaction, etc., it is preferably in the range of 1 to 2, and more preferably 1.

[0159] Z in the formulas (4-1) and (4-2) １ has a curable functional group Fg represented by the general formula (5). Examples of the curable functional group Fg include a hydroxyl group, an amino group, a carboxyl group, an acid anhydride group, an amide group, an imide group, a thiol group, and an ester group. A hydroxyl group, an amino group, a carboxyl group, or a thiol group is preferable, and a hydroxyl group or an amino group is more preferable. That is, in the general formula (5), the curable functional group Fg is a hydroxyl group (—OH) or an amine group (—NH ２ Z in the formulas (4-1) and (4-2) is preferably １ From the viewpoints of availability of raw materials and reactivity, the compound having the following structural formula is preferred.

[0160]

[0161] When the curable functional group of the curable functional group-containing compound (C) according to this embodiment is a hydroxyl group, examples of the curable functional group-containing compound (C) of the present invention include, but are not limited to, those represented by the following:

[0162]

[0163]

[0164]

[0165] [In the formula, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms, n is the average number of repeating units and is 0 to 10, n1 is an integer from 4 to 16, n2 is the average number of repeating units and is 2 to 30, and k1 is 0.5 to 5.]

[0166] Furthermore, when the curable functional group of the curable functional group-containing compound (C) according to this embodiment is an amino group, examples of the curable functional group-containing compound (C) of the present invention include, but are not limited to, those represented by the following:

[0167] [In the formula, m, n, p1, p2, and q are average values ​​of repeating units, each m is independently 0 to 25, n is 0 to 10, p1 and p2 are independently 0 to 5, and q is 0.5 to 5.]

[0168] The method for producing the curable functional group-containing compound (C) according to this embodiment is not particularly limited, and it may be produced stepwise using known reactions depending on the target structure, and it may also be obtained by appropriately combining commercially available raw materials. Representative synthesis methods are described below.

[0169] The general formulas (4-1) and (4-2) have, as reversible bonds, two Diels-Alder reaction units, which are addition reaction moieties formed by a Diels-Alder reaction consisting of a furan structure and a maleimide structure, in the molecule, and can be obtained by using a maleimide compound having the structure Z1 in the general formula (4-1) and a furan compound having the structure Z1 in the general formula (4-2).

[0170] It is widely known that the so-called Diels-Alder reaction, in which a conjugated diene such as a furan structure and a parent diene such as a maleimide structure undergo an addition reaction to form a six-membered ring, is an equilibrium reaction, and that at temperatures higher than the temperature at which the addition reaction proceeds, the addition reaction moiety dissociates to return to the original conjugated diene and parent diene, thereby causing a retro-Diels-Alder reaction, which is a reverse reaction.

[0171] Said Z １ Examples of maleimide compounds having the structure include any of the compounds listed in the following formulas. Among these, phenylmaleimides having a curable functional group (Fg) are preferred in terms of curability, and monofunctional phenylmaleimides are particularly preferred in terms of the balance between reactivity, cured product properties, and ease of disassembly. Among monofunctional phenylmaleimides, phenylmaleimides having a functional group at the para position are particularly preferred in terms of heat resistance.

[0172]

[0173] Said Z １ Examples of the furan compound having the structure shown below include any of the compounds shown in the following formulae:

[0174]

[0175] Among the above formulas, the compounds shown below are particularly preferred in terms of reactivity, physical properties of the cured product, and excellent adhesion, flexibility and dismantling properties of the resulting cured product.

[0176]

[0177] The maleimide compound and furan compound structures each independently include a hydrogen atom, a halogen atom, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amide group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group as a substituent. Furthermore, in the structures of the compounds listed in the formulas above, the alkoxy group, aralkyloxy group, aryloxy group, carboxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, an alkyl group, a cycloalkyl group, an aralkyl group, and an aryl group also include those in which various substituents are further bonded to the carbon atoms thereof.

[0178] The Diels-Alder reaction may be carried out by a known method. For example, a conjugated diene compound and a parent diene compound are mixed in equimolar amounts, or optionally one of the components may be in excess, and the mixture is melted by heating or dissolved in a solvent, followed by stirring at room temperature to 110°C for 1 to 24 hours. The resulting product can be obtained by filtration or solvent distillation without further purification, or by a commonly used isolation and purification method such as recrystallization, reprecipitation, or chromatography. The above "equimolar amounts of the conjugated diene compound and the parent diene compound" means that the conjugated diene structure of the conjugated diene compound and the ethylene structure of the parent diene compound are equimolar. For example, in the case of the glycidyl ether group-containing compound (C) represented by the above general formula (4), when the furan compound as the conjugated diene compound has one conjugated diene structure per molecule and the maleimide compound (bismaleimide) as the parent diene compound has two maleimide structures (ethylene structures) per molecule, the above phrase "equimolar amounts of the conjugated diene compound and the parent diene compound" means "a molar ratio of the furan compound to the maleimide compound (bismaleimide) of 2:1."

[0179] The moieties other than the reversible bond can be synthesized by known methods. For example, a diglycidyl ether of an aliphatic dihydroxy compound or an aliphatic divinyl ether is reacted with an aromatic hydroxy compound to obtain a compound having a hydroxy group at the terminal, and then the compound is reacted with furfuryl glycidyl ether or the like to introduce a furan structure at the terminal, and further, a Diels-Alder reaction is carried out with a maleimide compound having a curable functional group as described above to obtain the compound represented by the general formula (4-1).

[0180] Alternatively, a compound having a hydroxy group at the terminal is obtained, and then epoxidized to convert the terminal into a glycidyl ether group. Thereafter, the compound is reacted with furfuryl alcohol or the like to introduce a furan structure at the terminal. Further, the compound is subjected to a Diels-Alder reaction with a maleimide compound having a curable functional group as described above, thereby obtaining a compound represented by the general formula (1).

[0181] Alternatively, an aromatic dihydroxy compound is reacted with a dihalogenated alkyl compound or a dihalogenated aralkyl compound to obtain a compound having a halogenated alkyl group at the terminal, and then the compound is reacted with furfuryl alcohol or the like to introduce a furan structure at the terminal. Further, the compound is subjected to a Diels-Alder reaction with a maleimide compound having a curable functional group as described above, thereby obtaining the compound represented by the general formula (1).

[0182] The diglycidyl ether of the aliphatic dihydroxy compound is not particularly limited, and examples thereof include 1,11-undecanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, 1,13-tridecanediol, 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. These may be used alone or in combination of two or more.

[0183] Among these, compounds having a structure in which glycidyl groups are linked via ether groups to both ends of an alkylene chain having 12 to 14 carbon atoms are preferred because they provide an excellent balance between flexibility and heat resistance of the resulting cured product, and it is most preferred to use 1,12-dodecanediol diglycidyl ether, 1,13-tridecanediol, or 1,14-tetradecanediol diglycidyl ether.

[0184] The aliphatic divinyl ether is not particularly limited, and examples thereof include divinyl ethers of linear alkylene groups such as polyethylene glycol divinyl ether, polypropylene glycol divinyl ether, polytetramethylene glycol divinyl ether, 1,3-butylene glycol divinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, 1,9-nonanediol divinyl ether, and 1,10-decanediol divinyl ether, and divinyl ethers of branched alkylene groups such as neopentyl glycol divinyl ether, divinyl ethers containing a cycloalkane structure such as 1,4-cyclohexanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, tricyclodecanediol divinyl ether, tricyclodecane dimethanol divinyl ether, pentacyclopentadecanedimethanol divinyl ether, and pentacyclopentadecanediol divinyl ether, bisphenol A divinyl ether, bisphenol F divinyl ether, and hydroquinone divinyl ether. These may be used alone or in combination of two or more.

[0185] Among these, divinyl ethers having a polyether structure or a linear alkylene chain having 4 to 10 carbon atoms are preferred because they provide an excellent balance between flexibility and toughness in the resulting cured product, and it is most preferred to use polyethylene glycol divinyl ether, polypropylene glycol divinyl ether, polytetramethylene glycol divinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, 1,9-nonanediol divinyl ether, or 1,10-decanediol divinyl ether.

[0186] The aromatic hydroxy compound is not particularly limited, and examples thereof include dihydroxybenzenes such as hydroquinone, resorcinol, and catechol; trihydroxybenzenes such as pyrogallol, 1,2,4-trihydroxybenzene, and 1,3,5-trihydroxybenzene; triphenylmethane-type phenols such as 4,4',4"-trihydroxytriphenylmethane; dihydroxynaphthalenes such as 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene; tetrafunctional phenols such as 1,1'-methylenebis-(2,7-naphthalenediol), 1,1'-binaphthalene-2,2',7,7'-tetraol, and 1,1'-oxybis-(2,7-naphthalenediol) obtained by coupling reaction of dihydroxynaphthalenes; bisphenols such as bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 1,1-bis(4-hydroxyphenyl)-1-phenylethane, and bis(4-hydroxyphenyl)sulfone, 2,2'-biphenol, 4,4'-biphenol, (1,1'-biphenyl)-3,4-diol, 3,3'-dimethyl-(1,1'-biphenyl)-4,4'-diol, 3-methyl-(1,1'-biphenyl)-4,4'-diol, 3,3',5,5'-tetramethylbiphenyl-2,2'-diol, 3,3',5,5'-tetramethylbiphenyl-4,4'-diol, 5-methyl-(1,1'-biphenyl)-3,4'diol, 3'-methyl-(1,1'-biphenyl)-3,4'diol, 4'-methyl-(1,1'-biphenyl)-3,Examples of suitable phenolic compounds include biphenols such as 4'-diol, alicyclic structure-containing phenols such as polyadducts of phenol and dicyclopentadiene and polyadducts of phenol and terpene compounds, naphthols such as bis(2-hydroxy-1-naphthyl)methane and bis(2-hydroxy-1-naphthyl)propane, and so-called Xylok-type phenolic resins, which are condensation reaction products of phenol and phenylene dimethyl chloride or biphenylene dimethyl chloride. These compounds may be used alone or in combination of two or more. Furthermore, bifunctional phenolic compounds in which the aromatic nucleus of each of the above compounds is substituted with a methyl group, t-butyl group, or halogen atom as a substituent are also included. The alicyclic structure-containing phenols and the Xylok-type phenolic resins may contain not only bifunctional components but also trifunctional or higher functional components. These compounds may be used as is, or the bifunctional components may be isolated and used after purification using a column or other purification process.

[0187] Among these, bisphenols are preferred because they provide an excellent balance between flexibility and toughness when cured, and bis(4-hydroxyphenyl)methane and 2,2-bis(4-hydroxyphenyl)propane are particularly preferred because of their outstanding toughness-imparting properties. Furthermore, when importance is placed on the moisture resistance of the cured product, it is preferable to use phenols containing an alicyclic structure.

[0188] The reaction ratio of the diglycidyl ether of the aliphatic dihydroxy compound to the aromatic hydroxy compound is preferably in the range of 1 / 1.01 to 1 / 5.0 (molar ratio) of the former / the latter, and from the viewpoint of providing a well-balanced combination of flexibility and heat resistance of the resulting cured product, it is preferable that (a1) / (a2) is 1 / 1.02 to 1 / 3.0 (molar ratio).

[0189] The reaction between the diglycidyl ether of an aliphatic dihydroxy compound and the aromatic hydroxy compound is preferably carried out in the presence of a catalyst. Various catalysts can be used, including 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 DMP-30, DMAP, tetramethylammonium, tetraethylammonium, tetrabutylammonium, and benzyltributylammonium, quaternary ammonium salts such as chlorides, bromides, and iodides such as tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, and benzyltributylphosphonium, tertiary amines such as triethylamine, N,N-dimethylbenzylamine, 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. Two or more of these catalysts may be used in combination. Among these, sodium hydroxide, potassium hydroxide, triphenylphosphine, and DMP-30 are preferred because they allow the reaction to proceed quickly and are highly effective 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 0.01 moles per mole of hydroxyl groups in the aromatic hydroxy compound. The form of these catalysts is also not particularly limited, and they may be used in the form of an aqueous solution or in the form of a solid.

[0190] The reaction between the diglycidyl ether of the aliphatic dihydroxy compound and the aromatic hydroxy compound can be carried out in the absence of a solvent or in the presence of an organic solvent. Examples of organic solvents that can be used include methyl cellosolve, ethyl cellosolve, toluene, xylene, methyl isobutyl ketone, dimethyl sulfoxide, propyl alcohol, and butyl alcohol. The amount of organic solvent used is typically 50 to 300% by mass, preferably 100 to 250% by mass, based on the total mass of the raw materials charged. These organic solvents can be used alone or in combination. The use of no solvent is preferred to rapidly carry out the reaction, while the use of dimethyl sulfoxide is preferred to reduce impurities in the final product.

[0191] The reaction temperature when carrying out the reaction is typically 50 to 180°C, and the reaction time is typically 1 to 10 hours. A reaction temperature of 100 to 160°C is preferred from the viewpoint of reducing impurities in the final product. Furthermore, if the resulting compound exhibits significant coloration, an antioxidant or a reducing agent may be added to suppress this. The antioxidant is not particularly limited, but examples thereof include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite ester compounds containing a trivalent phosphorus atom. The reducing agent is not particularly limited, but examples thereof include hypophosphorous acid, phosphorous acid, thiosulfuric acid, sulfurous acid, hydrosulfite, or salts thereof.

[0192] After completion of the reaction, the reaction mixture may be neutralized or washed with water until the pH reaches 3 to 7, preferably 5 to 7. The neutralization and washing may be carried out in a conventional manner. For example, when a basic catalyst is used, an acidic substance such as hydrochloric acid, sodium dihydrogen phosphate, p-toluenesulfonic acid, or oxalic acid may be used as a neutralizing agent. After neutralization or washing, the solvent may be distilled off under reduced pressure and heating, if necessary, and the product may be concentrated to obtain the compound.

[0193] The reaction ratio of the aliphatic divinyl ether to the aromatic hydroxy compound is preferably in the range of 1 / 1.01 to 1 / 5.0 (molar ratio) of the former / the latter, and from the viewpoint of providing a well-balanced cured product having flexibility and heat resistance, it is preferable that (a1) / (a2) is in the range of 1 / 1.02 to 1 / 3.0 (molar ratio).

[0194] The reaction between the diglycidyl ether of the aliphatic dihydroxy compound and the aromatic hydroxy compound proceeds sufficiently without a catalyst, but a catalyst can be used as appropriate to select the raw materials and increase the reaction rate. Examples of catalysts that can be used include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid; organic acids such as toluenesulfonic acid, methanesulfonic acid, xylenesulfonic acid, trifluoromethanesulfonic acid, oxalic acid, formic acid, trichloroacetic acid, and trifluoroacetic acid; and Lewis acids such as aluminum chloride, iron chloride, tin chloride, gallium chloride, titanium chloride, aluminum bromide, gallium bromide, boron trifluoride ether complex, and boron trifluoride phenol complex. The amount of catalyst used is typically in the range of 10 ppm to 1 wt % based on the mass of the divinyl ether compound. In this case, it is preferable to select the type and amount of catalyst used so as not to cause a nucleation reaction of the vinyl group to the aromatic ring.

[0195] The reaction between the aliphatic divinyl ether and the aromatic hydroxy compound can be carried out in the absence of a solvent or in the presence of an organic solvent. Examples of suitable organic solvents include aromatic organic solvents such as benzene, toluene, and xylene; ketone-based organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and alcohol-based organic solvents such as methanol, ethanol, isopropyl alcohol, and normal butanol. The amount of organic solvent used is typically 50 to 300% by mass, preferably 100 to 250% by mass, based on the total mass of the raw materials charged. These organic solvents can be used alone or in combination.

[0196] The reaction temperature when carrying out the reaction is usually 50 to 150° C., and the reaction time is usually 0.5 to 10 hours. In this case, the reaction is preferably carried out in an oxygen atmosphere in order to prevent self-polymerization of the vinyl ether group.

[0197] After completion of the reaction, if an organic solvent was used, it is removed under reduced pressure and heating, and if a catalyst was used, it is deactivated with a deactivator or the like as necessary, and then removed by washing with water or filtration, thereby obtaining a compound.

[0198] The compound having a terminal hydroxyl group thus obtained is reacted with furfuryl glycidyl ether or the like. Sodium hydroxide, potassium hydroxide, potassium carbonate, or the like can be used as a catalyst, and toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetonitrile, dimethylformamide, or the like can be used as a solvent. The reaction temperature is room temperature to 200°C, and the reaction time is 1 to 24 hours. The catalyst is then removed by filtration or the like, and the target compound can be obtained by extraction, solvent removal, or the like. The Diels-Alder reaction of this compound is as described above.

[0199] The aliphatic hydroxy compound is not particularly limited, and examples thereof include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, and 1,16-hexadecane. Examples of the diglycidyl ether include diol, 2-methyl-1,11-undecanediol, 3-methyl-1,11-undecanediol, 2,6,10-trimethyl-1,11-undecanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polypentamethylene glycol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, and polyheptamethylene glycol diglycidyl ether. These may be used alone or in combination of two or more.

[0200] Among these, it is preferable to use a dihydroxy compound having a polyether structure or a linear alkylene chain having 12 to 14 carbon atoms, because it provides an excellent balance between flexibility and heat resistance of the resulting cured product, and it is most preferable to use polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,12-dodecanediol, 1,13-tridecanediol, or 1,14-tetradecanediol.

[0201] The dihalogenated alkyl compound is not particularly limited, and examples thereof include 1,4-dichlorobutane, 1,5-dichloropentane, 1,6-dichlorohexane, 1,7-dichloroheptane, 1,8-dichlorooctane, 1,9-dichlorononane, 1,10-dichlorodecane, 1,11-dichloroundecane, 1,12-dichlorododecane, 1,4-dibromobutane, 1,5-dibromopentane, 1,6-dibromohexane, 1,7-dibromoheptane, 1,8-dibromooctane, 1,9-dibromononane, 1,10-dibromodecane, 1,11-dibromoundecane, and 1,12-dibromododecane. These compounds may be used alone or in combination of two or more.

[0202] The dihalogenated aralkyl compound is not particularly limited, and examples thereof include dichloroxylene, dichloromethylbiphenyl, dibromoxylene, dibromomethylbiphenyl, etc., and these compounds may be used alone or in combination of two or more.

[0203] The reaction ratio of the aromatic dihydroxy compound to the dihalogenated alkyl compound or dihalogenated aralkyl compound is preferably in the range of 1 / 1.01 to 1 / 5.0 (molar ratio) of the former / the latter, and from the viewpoint of providing a well-balanced combination of flexibility and heat resistance of the resulting cured product, it is preferable that (a1) / (a2) is 1 / 1.02 to 1 / 3.0 (molar ratio).

[0204] The reaction between the aromatic dihydroxy compound and the dihalogenated alkyl compound or dihalogenated aralkyl compound is preferably carried out in the presence of a catalyst. Various catalysts can be used, including, for example, alkali (earth) metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide, and alkali metal carbonates such as sodium carbonate and potassium carbonate. Two or more of these catalysts may be used in combination. Among these, sodium hydroxide, potassium hydroxide, and potassium carbonate are preferred because they rapidly promote the reaction and are highly effective in reducing the amount of impurities. The amount of these catalysts used is not particularly limited, but is preferably 0.0001 to 10 moles per mole of hydroxyl groups in the aromatic hydroxy compound. The form of these catalysts is also not particularly limited, and they may be used in the form of an aqueous solution or a solid.

[0205] The reaction of the aromatic dihydroxy compound with the alkyl dihalide compound or aralkyl dihalide compound can be carried out in the absence of a solvent or in the presence of an organic solvent. Usable organic solvents include, for example, toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetonitrile, and dimethylformamide. The amount of the organic solvent used is typically 50 to 300% by mass, preferably 100 to 1000% by mass, based on the total mass of the raw materials charged. These organic solvents can be used alone or in combination.

[0206] The reaction temperature when carrying out the reaction is usually room temperature to 150° C., and the reaction time is usually 1 to 24 hours. From the viewpoint of reducing impurities in the final product, the reaction temperature is preferably room temperature to 100° C.

[0207] The compound having a halogenated alkyl group at the end obtained in this manner is reacted with furfuryl alcohol or the like. Sodium hydroxide, potassium hydroxide, potassium carbonate, or the like can be used as a catalyst, and toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetonitrile, dimethylformamide, or the like can be used as a solvent. The reaction temperature is room temperature to 200°C, and the reaction time is 1 to 24 hours. The catalyst is then removed by filtration or the like, and the target compound can be obtained by extraction, solvent removal, or the like. The Diels-Alder reaction of this compound is as described above.

[0208] [Thermal-Expandable Particles (D)] The thermal-expandable particles (D) contained in the curable resin composition of this embodiment may be made of either an inorganic material or an organic material. Examples of inorganic materials include the thermally expandable graphite disclosed in JP-A-2000-44219. Examples of organic materials include thermally expandable microcapsules in which a thermoplastic polymer is used as an outer shell and a volatile expanding agent that becomes gaseous at a temperature below the softening point of the thermoplastic polymer is microencapsulated.

[0209] Among these, it is preferable to use thermally expandable microcapsules made of an organic material from the viewpoint of uniform dispersibility and excellent electrical insulation when made into a curable resin composition, and it is also preferable to use thermally expandable graphite from the viewpoint of heat resistance durability and electrical conductivity of the expandable particles.

[0210] "Thermally Expandable Microcapsules" A method for producing the thermally expandable microcapsules has been disclosed in Japanese Patent Publication No. 42-26524, but from the viewpoint of thermally curing the epoxy resin in this embodiment, it is preferable that the microcapsules have heat resistance. Methods for producing heat-resistant thermally expandable microcapsules are disclosed in, for example, WO99 / 46320, WO99 / 43758, and Japanese Patent Laid-Open No. 2002-226620.

[0211] In other words, from the viewpoint that it is preferable for the particles to maintain their shape as particles without thermal expansion during thermal curing of the epoxy resin, and to expand at high temperatures due to thermal energy after use, it is preferable for the particles to be thermally expandable microcapsules having a shell polymer that is a polymer obtained by polymerizing a nitrile-based monomer and a monomer having a carboxyl group as essential components.

[0212] In order to further impart heat resistance, it is also preferable to use a monomer having an amide group or a monomer having a cyclic structure in the side chain in combination.

[0213] To obtain the heat-resistant thermally expandable microcapsules, for example, the shell polymer can be prepared by blending the above-mentioned components with an appropriate polymerization initiator. Known polymerization initiators, such as peroxides and azo compounds, can be used as the polymerization initiator. Examples include azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, diisopropyl peroxydicarbonate, t-butyl peroxide, and 2,2'-azobis(2,4-dimethylvaleronitrile). Preferably, an oil-soluble polymerization initiator that is soluble in the polymerizable monomer used is used. The glass transition temperature (Tg) of the polymer constituting the outer shell of the thermally expandable microcapsules is desirably 120°C or higher. The Tg of the polymer can be calculated from the Tg of each homopolymer of the constituent monomers. It can also be measured by differential scanning calorimetry (DSC) or other methods.

[0214] The blowing agent contained in the microcapsules is a substance that becomes gaseous below the softening point of the shell polymer, and known substances are used. Examples include low-boiling liquids such as propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, nonane, decane, petroleum ether, methane halides, tetraalkylsilanes, and compounds such as AIBN that become gaseous upon thermal decomposition upon heating. The blowing agent is selected as needed depending on the temperature range in which the capsules are to be foamed. The above blowing agents are used alone or in combination of two or more.

[0215] Further, fluorine-based compounds such as HCF, HCFC, HFC, and HFE, commonly known as chlorofluorocarbons, fluorocarbons, and fluoroethers, are also exemplified, but their use is best avoided in the current social situation due to concerns about ozone layer destruction and global warming. In actual production, conventional methods for producing thermally expandable microcapsules are generally used. That is, inorganic fine particles such as silica, magnesium hydroxide, calcium phosphate, and aluminum hydroxide are used as dispersion stabilizers in aqueous systems. Other examples of dispersion stabilization aids include condensation products of diethanolamine and aliphatic dicarboxylic acids, polyvinylpyrrolidone, methylcellulose, polyethylene oxide, polyvinyl alcohol, and various emulsifiers.

[0216] The average particle size of the thermally expandable microcapsules is 1 to 500 μm, preferably 3 to 100 μm, and more preferably 5 to 50 μm. The average particle size of the thermally expandable microcapsules can be measured by, for example, measuring the volume average particle size using a particle size distribution diameter measuring instrument (LA-950, manufactured by HORIBA).

[0217] "Thermally Expandable Graphite" A method for producing the thermally expandable graphite is disclosed in, for example, JP 2000-44219 A, but from the viewpoint of thermally curing the epoxy resin in this embodiment, it is preferable that the graphite has heat resistance. A method for producing heat-resistant thermally expandable graphite is disclosed in, for example, JP 2012-193053 A, for example.

[0218] Thermally expandable graphite can usually be obtained by treating graphite such as natural graphite, pyrolytic graphite, or kish graphite with a mixture of concentrated sulfuric acid and a strong oxidizing agent (hereinafter referred to as acid treatment) to form an intercalation compound between the graphite layers, followed by washing with water, filtering, and drying. Common acid treatment methods include those 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. Methods using only fuming nitric acid are also known.

[0219] Thermally expandable graphite is selected based on the range of the longest diameter of the particles. For this reason, commercially available expandable graphite is expressed in terms of particle size instead of longest diameter. Specifically, commercially available expandable graphite is classified using a sieve, and the properties of the expandable graphite product are expressed based on the mesh size and the percentage of particles that pass through the sieve.

[0220] The particle size of the thermally expandable graphite used as the thermally expandable particles (D) according to this embodiment is preferably 20 to 300 mesh, more preferably 30 to 200 mesh.

[0221] The average particle size of the thermally expandable particles (D) is 1 to 500 μm, preferably 3 to 100 μm, and more preferably 5 to 50 μm.

[0222] The thermally expandable particles (D) may be directly mixed with the epoxy resin (A) and the epoxy resin (B), or may be mixed with the epoxy resin (A) and the epoxy resin (B) using a master batch in which the thermally expandable particles (D) are dispersed in various resins at a high concentration.

[0223] As such thermally expandable particles (D), commercially available products can also be used. Examples of commercially available products include microspheres manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd. (trade names: F-20D, F-30D, F-40D, FN-100D, FN-100MD, FN-100SD, FN-100SSD, FN-180D, FN-180SD, FN-180SSD, F-190D, F-260D), microspheres manufactured by Kureha Corporation (trade names: H850D, H880D, S2340D, S2640D), and microspheres manufactured by Fuji Kogyo Co., Ltd. Examples of such graphite include expanded graphite manufactured by Ito Graphite Co., Ltd. (product names: EXP-50S120K, EXP-50S150), expanded graphite manufactured by Ito Graphite Co., Ltd. (product names: 953240L, 9550250), and thermally expandable graphite manufactured by Air Water Co., Ltd. (product names: 50LTE-U, MZ-260, CA-60, SS-3, SS-3LA). It is preferable to appropriately select particles that do not thermally expand at the curing temperature of the curable resin composition but thermally expand at the heating temperature during dismantling.

[0224] The proportion of the thermally expandable particles (D) used is preferably in the range of 3 to 40 parts by mass, 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, relative to 100 parts by mass of the total of the epoxy resin (A) and the epoxy resin (B), from the viewpoint of exhibiting the effect of sufficiently expanding and reducing adhesiveness when dismantling the composition after use without impairing the adhesiveness when curing the curable resin composition of the present embodiment or the flexibility of the cured product.

[0225] (hardening agent)

[0226] The curable resin composition of the present embodiment may further contain a curing agent for epoxy resins that does not belong to the curable functional group-containing compound (C).

[0227] Examples of the curing agent that can be used here include various known curing agents for epoxy resins, such as amine compounds that do not belong to the curable functional group-containing compound (C), acid anhydrides, amide compounds, hydroxyl group-containing compounds that do not belong to the curable functional group-containing compound (C), carboxylic acid compounds, and thiol compounds.

[0228] Examples of the amine compound include trimethylenediamine, ethylenediamine, N,N,N',N'-tetramethylethylenediamine, pentamethyldiethylenetriamine, triethylenediamine, dipropylenediamine, N,N,N',N'-tetramethylpropylenediamine, tetramethylenediamine, pentanediamine, hexamethylenediamine, trimethylhexamethylenediamine, N,N,N',N'-tetramethylhexamethylenediamine, N,N-dimethylcyclohexylamine, diethylenetriamine, triethylenetetramine, tetramethylhexamethylenediamine ... aliphatic amine compounds such as triethylenepentamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, 1,4-diazabicyclo(2,2,2)octane (triethylenediamine), polyoxyethylenediamine, polyoxypropylenediamine, bis(2-dimethylaminoethyl)ether, dimethylaminoethoxyethoxyethanol, triethanolamine, dimethylaminohexanol, benzylmethylamine, dimethylbenzylamine, m-xylenediamine, and α-methylbenzylmethylamine;

[0229] 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);

[0230] Aromatic amine compounds such as o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, pyridine, and picoline;

[0231] Examples of the modified amine compounds include epoxy compound-added polyamines, Michael addition polyamines, Mannich addition polyamines, thiourea addition polyamines, ketone-blocked polyamines, dicyandiamide, guanidine, organic acid hydrazides, diaminomaleonitrile, aminimide, boron trifluoride-piperidine complex, and boron trifluoride-monoethylamine complex.

[0232] Examples of the acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, maleic anhydride polypropylene glycol, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0233] Examples of the hydroxyl group-containing compound include bisphenols such as bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 1,1-bis(4-hydroxyphenyl)-1-phenylethane, and bis(4-hydroxyphenyl)sulfone, phenol novolac resin, cresol novolac resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin (Zylok resin), naphthol aralkyl resin, trimethylolmethane resin, tetra ... Examples of polyhydric phenol compounds include phenylolethane resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, biphenyl-modified phenol resin (a polyhydric phenol compound in which phenol nuclei are linked via bismethylene groups), biphenyl-modified naphthol resin (a polyhydric naphthol compound in which phenol nuclei are linked via bismethylene groups), aminotriazine-modified phenol resin (a polyhydric phenol compound in which phenol nuclei are linked via melamine, benzoguanamine, or the like), and alkoxy group-containing aromatic ring-modified novolac resin (a polyhydric phenol compound in which phenol nuclei and alkoxy group-containing aromatic rings are linked via formaldehyde).

[0234] Examples of the amide compounds include dicyandiamide and polyamidoamine, etc. Examples of the polyamidoamine include those obtained by reacting an aliphatic dicarboxylic acid such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, or azelaic acid, or a carboxylic acid compound such as a fatty acid or dimer acid, with an aliphatic polyamine or a polyamine having a polyoxyalkylene chain.

[0235] Examples of the carboxylic acid compound include carboxylic acid polymers such as carboxylic acid-terminated polyester, polyacrylic acid, and maleic acid-modified polypropylene glycol.

[0236] The thiol compound preferably contains two or more thiol groups in one molecule. Examples thereof include 3,3'-dithiodipropionic acid, trimethylolpropane tris(thioglycolate), pentaerythritol tetrakis(thioglycolate), ethylene glycol dithioglycolate, 1,4-bis(3-mercaptobutyryloxy)butane, tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), dipentaerythritol hexakis(3-mercaptopropionate), 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, 4-butanedithiol, 1,6-hexaneedithiol, and 1,10-decanedithiol.

[0237] When using these curing agents, only one type of curing agent may be used, or two or more types may be mixed. For applications such as underfill materials and general coating applications, it is preferable to use the amine-based compounds, carboxylic acid-based compounds, and / or acid anhydride-based compounds. For applications such as adhesives and flexible wiring boards, amine-based compounds, particularly dicyandiamide, are preferred in terms of workability, curability, and long-term stability. For applications as semiconductor encapsulation materials, solid phenol-based compounds are preferred in terms of the heat resistance of the cured product. For applications as batteries, aliphatic amines and thiol compounds are preferred in terms of low-temperature curing.

[0238] The amounts of epoxy resin and curing agent used are not particularly limited, but in terms of the good mechanical properties of the resulting cured product, it is preferable that the amount of active groups reactive with epoxy groups, including the hydroxyl group-containing cured product of the present invention, is 0.4 to 1.5 equivalents per total equivalent of epoxy groups in the resin composition.

[0239] [Other Epoxy Resins] The curable resin composition of the present embodiment may further contain other epoxy resins that do not belong to the epoxy resin (A) or the epoxy resin (B) according to the present embodiment, within a range that does not impair the effects of the present embodiment. In this case, the total amount of the epoxy resin (A) and the epoxy resin (B) in the curable resin composition of the present embodiment is preferably 30 mass % or more, and particularly preferably 40 mass % or more, of the total epoxy resins.

[0240] Other epoxy resins that can be used in combination are not limited in any way as long as they do not belong to the epoxy resin (A) or the epoxy resin (B), and examples thereof include liquid epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD ​​type epoxy resins, polyhydroxybenzene type epoxy resins, polyhydroxynaphthalene type epoxy resins, biphenyl type epoxy resins, and tetramethylbiphenyl type epoxy resins; brominated epoxy resins such as brominated phenol novolac type epoxy resins; solid bisphenol A type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins; and triphenylmethane

[0033] Examples of epoxy resins include phenol aralkyl type epoxy resins, tetraphenylethane type epoxy resins, dicyclopentadiene-phenol addition reaction type epoxy resins, phenol aralkyl type epoxy resins, phenylene ether type epoxy resins, naphthylene ether type epoxy resins, naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins, aromatic hydrocarbon formaldehyde resin-modified phenol resin type epoxy resins, and biphenyl-modified novolac type epoxy resins. These may be used alone or in combination of two or more kinds, and it is preferable to select and use various types depending on the intended use, the physical properties of the cured product, and the like.

[0241] The concentration of reversible bonds in the curable resin composition of this embodiment is preferably 0.10 mmol / g or more relative to the total mass of the curable components in the curable resin composition. According to this configuration, the adhesiveness, flexibility, and dismantling properties of the cured product obtained from the curable resin composition are all further improved. The concentration of the reversible bonds is more preferably 0.10 to 3.00 mmol / g, and even more preferably 0.15 to 2.00 mmol / g. Furthermore, when the curable functional group-containing compound (C) of this embodiment contains multiple reversible bonds, or when the hydroxyl group-containing compound having the reversible bonds is used alone or in combination with another curing agent as a curing agent, the total concentration of the reversible bonds is preferably 0.10 mmol / g or more relative to the total mass of the curable components in the curable resin composition, more preferably 0.10 to 3.00 mmol / g, and even more preferably 0.15 to 2.00 mmol / g. The concentration of the reversible bond can be appropriately selected based on the glass transition temperature, defined by the tan δ peak top of the target cured product measured by a dynamic viscoelasticity analyzer (DMA). For example, when the glass transition temperature is used as a guideline, if the glass transition temperature of the cured product is near room temperature, sufficient adhesiveness, flexibility, and dismantling properties are likely to be exhibited even at the low concentration side of the preferred range. On the other hand, if the glass transition temperature of the target cured product is above 100 ° C. as a guideline, the functions are likely to be exhibited at the high concentration side of the preferred range. However, in the temperature range above the glass transition temperature measured by DMA, molecular mobility is generally high, and sufficient adhesiveness, flexibility, and dismantling properties are likely to be exhibited even at a low concentration of the curable functional group-containing compound (C). Therefore, for example, the effects of exhibiting adhesiveness, flexibility, and dismantling properties can be adjusted by appropriately adjusting the aging temperature for curing or the heating temperature for dismantling. Thus, the relationship between the glass transition temperature of the cured product and the concentration of the reversible bond is not limited to these.

[0242] The ratio of the total number of glycidyl ether groups to the total number of active groups capable of reacting with these glycidyl ether groups in the curable resin composition of the present embodiment is not particularly limited, but in terms of good mechanical properties and the like of the resulting cured product, it is preferable that the amount of active groups capable of reacting with glycidyl ether groups be 0.4 to 1.5 equivalents per equivalent of the total number of glycidyl ether groups in the resin composition.

[0243] [Curing Accelerator] The curable resin composition of this embodiment may contain a curing accelerator. Various curing accelerators can be used, including urea compounds, phosphorus compounds, tertiary amines, imidazoles, imidazolines, organic acid metal salts, Lewis acids, and amine complex salts. When used as an adhesive, urea compounds, particularly 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), are preferred because of their excellent workability and low-temperature curing properties. When used as a semiconductor encapsulating material, triphenylphosphine is a preferred phosphorus compound, and 1,8-diazabicyclo-[5.4.0]-undecene is a preferred tertiary amine because of their excellent curability, heat resistance, electrical properties, and moisture resistance reliability.

[0244] Examples of the phosphorus compound include alkyl phosphines such as ethylphosphine and butylphosphine, primary phosphines such as phenylphosphine, dialkyl phosphines such as dimethylphosphine and dipropylphosphine, secondary phosphines such as diphenylphosphine and methylethylphosphine, and tertiary phosphines such as trimethylphosphine, triethylphosphine and triphenylphosphine.

[0245] Examples of the imidazole include imidazole, 1-methylimidazole, 2-methylimidazole, 3-methylimidazole, 4-methylimidazole, 5-methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 3-ethylimidazole, 4-ethylimidazole, 5-ethylimidazole, 1-n-propylimidazole, 2-n-propylimidazole, 1-isopropylimidazole, 2-isopropylimidazole, isopropylimidazole, 1-n-butylimidazole, 2-n-butylimidazole, 1-isobutylimidazole, 2-isobutylimidazole, 2-undecyl-1H-imidazole, 2-heptadecyl-1H-imidazole, 1,2-dimethylimidazole, 1,3-dimethylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 1-phenylimidazole, 2-phenyl-1H-imidazole Imidazole, 4-methyl-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 socyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-phenyl-4,5-di(2-cyanoethoxy)methylimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 1-benzyl-2-phenylimidazole hydrochloride, and the like.

[0246] Examples of the imidazoline compound include 2-methylimidazoline and 2-phenylimidazoline.

[0247] Examples of the urea compound include p-chlorophenyl-N,N-dimethylurea, 3-phenyl-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-N,N-dimethylurea, and N-(3-chloro-4-methylphenyl)-N',N'-dimethylurea.

[0248] [Other Thermosetting Resins and Thermoplastic Resins] The curable resin composition of the present embodiment may be used in combination with other thermosetting resins or thermoplastic resins within a range that does not impair the effects of the present embodiment.

[0249] Examples of other thermosetting resins include cyanate ester resins, resins having a benzoxazine structure, active ester resins, vinylbenzyl compounds, acrylic compounds, copolymers of styrene and maleic anhydride, etc. When the other thermosetting resins described above are used in combination, the amount used is not particularly limited as long as it does not inhibit the effects of this embodiment, but is preferably in the range of 1 to 50 parts by mass per 100 parts by mass of the curable resin composition.

[0250] Examples of the cyanate ester resin include bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, bisphenol E type cyanate ester resin, bisphenol S type cyanate ester resin, bisphenol sulfide type cyanate ester resin, phenylene ether type cyanate ester resin, naphthylene ether type cyanate ester resin, biphenyl type cyanate ester resin, tetramethylbiphenyl type cyanate ester resin, polyhydroxynaphthalene type cyanate ester resin, phenol novolac type cyanate ester resin, cresol novolac type cyanate ester resin, triphenyl Examples of suitable cyanate ester resins include tetraphenylethane-type cyanate ester resins, dicyclopentadiene-phenol addition reaction-type cyanate ester resins, phenol aralkyl-type cyanate ester resins, naphthol novolac-type cyanate ester resins, naphthol aralkyl-type cyanate ester resins, naphthol-phenol co-condensed novolac-type cyanate ester resins, naphthol-cresol co-condensed novolac-type cyanate ester resins, aromatic hydrocarbon formaldehyde resin-modified phenolic resin-type cyanate ester resins, biphenyl-modified novolac-type cyanate ester resins, and anthracene-type cyanate ester resins. These may be used alone or in combination of two or more.

[0251] Among these cyanate ester resins, bisphenol A-type cyanate ester resins, bisphenol F-type cyanate ester resins, bisphenol E-type cyanate ester resins, polyhydroxynaphthalene-type cyanate ester resins, naphthylene ether-type cyanate ester resins, and novolac-type cyanate ester resins are preferred in terms of the ability to obtain cured products with particularly excellent heat resistance, and dicyclopentadiene-phenol addition reaction-type cyanate ester resins are preferred in terms of the ability to obtain cured products with excellent dielectric properties.

[0252] The resin having a benzoxazine structure is not particularly limited, and examples thereof include a reaction product of bisphenol F, formalin, and aniline (Fa-type benzoxazine resin), a reaction product of diaminodiphenylmethane, formalin, and phenol (P-d-type benzoxazine resin), a reaction product of bisphenol A, formalin, and aniline, a reaction product of dihydroxydiphenyl ether, formalin, and aniline, a reaction product of diaminodiphenyl ether, formalin, and phenol, a reaction product of a dicyclopentadiene-phenol addition type resin, formalin, and aniline, a reaction product of phenolphthalein, formalin, and aniline, and a reaction product of diphenyl sulfide, formalin, and aniline. These may be used alone or in combination of two or more.

[0253] The active ester resin is not particularly limited, but compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are generally preferred. The active ester resin is preferably one obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. From the viewpoint of improving heat resistance in particular, active ester resins obtained from a carboxylic acid compound or its halide and a hydroxy compound are preferred, and active ester resins obtained from a carboxylic acid compound or its halide and a phenol compound and / or a naphthol compound are more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, and the like, or halides thereof. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, dihydroxydiphenyl ether, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, and dicyclopentadiene-phenol adduct resins.

[0254] Specific examples of preferred active ester resins include active ester resins containing a dicyclopentadiene-phenol addition structure, active ester resins containing a naphthalene structure, active ester resins which are acetylated phenol novolac, and active ester resins which are benzoylated phenol novolac. Of these, active ester resins containing a dicyclopentadiene-phenol addition structure and active ester resins containing a naphthalene structure are more preferred in terms of their excellent ability to improve peel strength.

[0255] Furthermore, various novolak resins, addition polymerization resins of alicyclic diene compounds such as dicyclopentadiene and phenol compounds, modified novolak resins of hydroxyl group-containing compounds and alkoxy group-containing aromatic compounds, phenol aralkyl resins (Xylok resins), naphthol aralkyl resins, trimethylolmethane resins, tetraphenylolethane resins, biphenyl-modified phenol resins, biphenyl-modified naphthol resins, aminotriazine-modified phenol resins, and various vinyl polymers may be used in combination.

[0256] More specifically, the various novolak resins include polymers obtained by reacting a hydroxyl group-containing compound, such as phenol, phenylphenol, resorcinol, biphenyl, bisphenol such as bisphenol A or bisphenol F, naphthol, or dihydroxynaphthalene, with an aldehyde compound under acid catalyst conditions.

[0257] Examples of the various vinyl polymers include homopolymers of vinyl compounds such as polyhydroxystyrene, polystyrene, polyvinylnaphthalene, polyvinylanthracene, polyvinylcarbazole, polyindene, polyacenaphthylene, polynorbornene, polycyclodecene, polytetracyclododecene, polynortricyclene, and poly(meth)acrylate, and copolymers thereof.

[0258] Thermoplastic resin refers to a resin that can be melt-molded by heating. Specific examples thereof include polyethylene resin, polypropylene resin, polystyrene resin, rubber-modified polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate 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 resin, polyetherimide resin, polyethersulfone resin, polyarylate resin, thermoplastic polyimide resin, polyamideimide resin, polyetheretherketone resin, polyketone resin, liquid crystal polyester resin, fluororesin, syndiotactic polystyrene resin, and cyclic polyolefin resin. These thermoplastic resins can be used alone or in combination of two or more.

[0259] When these other resins are used, the blending ratio of the curable functional group-containing compound (C) of the present embodiment to the other resins can be set arbitrarily depending on the application. However, from the viewpoint of excellent adhesion, flexibility, and dismantling properties when formed into a cured product, it is preferable that the blending ratio be such that the other resin is 0.5 to 100 parts by mass per 100 parts by mass of the curable functional group-containing compound (C) of the present embodiment.

[0260] [Non-halogen flame retardant] When the curable resin composition of the present embodiment is used in an application requiring high flame retardancy, a non-halogen flame retardant that contains substantially no halogen atoms may be blended therein.

[0261] Examples of the non-halogen flame retardant include phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organic metal salt-based flame retardants. There are no limitations on the use of these flame retardants. They may be used alone, or multiple flame retardants of the same type may be used, or different flame retardants may be used in combination.

[0262] The phosphorus-based flame retardant may be either inorganic or organic. Examples of inorganic compounds include red phosphorus, ammonium phosphates such as monoammonium phosphate, diammonium phosphate, triammonium phosphate, and ammonium polyphosphate, and inorganic nitrogen-containing phosphorus compounds such as phosphoric acid amide.

[0263] The red phosphorus is preferably surface-treated to prevent hydrolysis and the like. Examples of the surface treatment method include (i) a method of coating with an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide, bismuth oxide, bismuth hydroxide, bismuth nitrate, or a mixture thereof; (ii) a method of coating with a mixture of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, or titanium hydroxide, and a thermosetting resin such as a phenolic resin; and (iii) a method of doubly coating with a thermosetting resin such as a phenolic resin on a coating of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, or titanium hydroxide.

[0264] Examples of the organic phosphorus compound include general-purpose organic phosphorus compounds such as phosphate ester compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphorane compounds, and organic nitrogen-containing phosphorus compounds, as well as cyclic organic phosphorus compounds such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-(2,7-dihydroxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and derivatives thereof obtained by reacting these with compounds such as epoxy resins and phenolic resins.

[0265] The amount of these phosphorus-based flame retardants to be added is appropriately selected depending on the type of phosphorus-based flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, when red phosphorus is used as the non-halogenated flame retardant, it is preferably added in an amount of 0.1 to 2.0 parts by mass, per 100 parts by mass of the resin composition containing all of the non-halogenated flame retardants and other fillers and additives, and when an organic phosphorus compound is used, it is similarly preferably added in an amount of 0.1 to 10.0 parts by mass, more preferably 0.5 to 6.0 parts by mass.

[0266] When the phosphorus-based flame retardant is used, it may be used in combination with hydrotalcite, magnesium hydroxide, boron compounds, zirconium oxide, black dyes, calcium carbonate, zeolite, zinc molybdate, activated carbon, or the like.

[0267] Examples of the nitrogen-based flame retardant include triazine compounds, cyanuric acid compounds, isocyanuric acid compounds, and phenothiazines, with triazine compounds, cyanuric acid compounds, and isocyanuric acid compounds being preferred.

[0268] Examples of the triazine compounds include melamine, acetoguanamine, benzoguanamine, melon, melam, succinoguanamine, ethylenedimelamine, melamine polyphosphate, triguanamine, and the like, as well as (1) aminotriazine sulfate compounds such as guanylmelamine sulfate, melem sulfate, and melam sulfate, (2) co-condensates of phenols such as phenol, cresol, xylenol, butylphenol, and nonylphenol with melamines such as melamine, benzoguanamine, acetoguanamine, and formguanamine and formaldehyde, (3) mixtures of the co-condensates of (2) with phenolic resins such as phenol-formaldehyde condensates, and (4) compounds obtained by further modifying (2) or (3) with tung oil, isomerized linseed oil, or the like.

[0269] Examples of the cyanuric acid compound include cyanuric acid and melamine cyanurate.

[0270] The amount of the 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 level of flame retardancy. For example, the amount is preferably 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, per 100 parts by mass of the resin composition containing the non-halogen flame retardant and all other fillers and additives.

[0271] When using the nitrogen-based flame retardant, a metal hydroxide, a molybdenum compound, or the like may be used in combination.

[0272] 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 to be added is selected appropriately depending on the type of silicone-based flame retardant, the other components of the resin composition, and the desired level of flame retardancy. It is preferable to add the silicone-based flame retardant in an amount ranging from 0.05 to 20 parts by mass per 100 parts by mass of the resin composition containing the non-halogen flame retardant and other fillers and additives. When using the silicone-based flame retardant, a molybdenum compound, alumina, or the like may also be used in combination.

[0273] Examples of the inorganic flame retardant include metal hydroxides, metal oxides, metal carbonate compounds, metal powders, boron compounds, and low-melting glass.

[0274] Examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, and zirconium hydroxide.

[0275] Examples of the metal oxide include zinc molybdate, molybdenum trioxide, zinc stannate, tin oxide, aluminum oxide, iron oxide, titanium oxide, manganese oxide, zirconium oxide, zinc oxide, molybdenum oxide, cobalt oxide, bismuth oxide, chromium oxide, nickel oxide, copper oxide, and tungsten oxide.

[0276] Examples of the metal carbonate compound include zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, basic magnesium carbonate, aluminum carbonate, iron carbonate, cobalt carbonate, and titanium carbonate.

[0277] Examples of the metal powder include aluminum, iron, titanium, manganese, zinc, molybdenum, cobalt, bismuth, chromium, nickel, copper, tungsten, and tin.

[0278] Examples of the boron compound include zinc borate, zinc metaborate, barium metaborate, boric acid, and borax.

[0279] Examples of the low-melting glass include glassy compounds such as Sheepley (Boxey Brown), hydrated glass SiO-MgO-H0, PbO-B2O3, ZnO-P2O5-MgO, P2O5-B2O3-PbO-MgO, P-Sn-O-F, PbO-V2O5-TeO2, Al2O3-H2O, and lead borosilicate.

[0280] The amount of the inorganic flame retardant to be added is appropriately selected depending on the type of inorganic flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, the amount is preferably 0.05 to 20 parts by mass, and more preferably 0.5 to 15 parts by mass, per 100 parts by mass of the resin composition containing the non-halogen flame retardant and all other fillers and additives.

[0281] Examples of the organometallic salt flame retardant include ferrocene, acetylacetonate metal complexes, organometallic carbonyl compounds, organic cobalt salt compounds, organic sulfonic acid metal salts, and compounds in which a metal atom is ionic- or coordinate-bonded to an aromatic compound or a heterocyclic compound.

[0282] The amount of the organometallic salt flame retardant to be blended is appropriately selected depending on the type of organometallic salt flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, it is preferably blended in the range of 0.005 to 10 parts by mass per 100 parts by mass of the resin composition containing all of the non-halogen flame retardant and other fillers and additives.

[0283] [Filler] The curable resin composition of this embodiment may contain a filler that does not belong to the thermally expandable particles (D) of this embodiment. Examples of the filler include inorganic fillers and organic fillers. Examples of the inorganic filler include inorganic fine particles.

[0284] Examples of inorganic fine particles include those with excellent heat resistance such as alumina, magnesia, titania, zirconia, and silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, and ultrafine amorphous silica); those with excellent thermal conductivity such as boron nitride, aluminum nitride, alumina oxide, titanium oxide, magnesium oxide, zinc oxide, silicon oxide, and diamond; those with excellent electrical conductivity such as metal fillers and / or metal-coated fillers using metals or alloys (e.g., iron, copper, magnesium, aluminum, gold, silver, platinum, zinc, manganese, and stainless steel); and those with excellent barrier properties such as minerals such as mica, clay, kaolin, talc, zeolite, wollastonite, and smectite, as well as potassium titanate, magnesium sulfate, sepiolite, and zonolite. tin, aluminum borate, calcium carbonate, titanium oxide, barium sulfate, zinc oxide, magnesium hydroxide; those with a high refractive index include barium titanate, zirconia oxide, titanium oxide, etc.; 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, composites of these metals, and oxides thereof; those with excellent wear resistance include metals such as silica, alumina, zirconia, and magnesium oxide, and composites and oxides thereof; those with excellent conductivity include metals such as silver and copper, tin oxide, indium oxide, etc.; those with excellent insulation properties include silica, etc.; and those with excellent UV blocking properties include titanium oxide and zinc oxide, etc. These inorganic particles can be selected appropriately depending on the application, and can be used alone or in combination. Furthermore, the above inorganic particles have various properties in addition to the properties listed above, so they can be selected appropriately depending on the application.

[0285] For example, when silica is used as the inorganic fine particles, known silica fine particles such as powdered silica and colloidal silica can be used without any particular limitation. Examples of commercially available powdered silica fine particles include Aerosil 50 and 200 manufactured by Nippon Aerosil Co., Ltd., Sildex H31, H32, H51, H52, H121, and H122 manufactured by Asahi Glass Co., Ltd., E220A and E220 manufactured by Nippon Silica Industry Co., Ltd., SYLYSIA 470 manufactured by Fuji Silysia Co., Ltd., and SG Flake manufactured by Nippon Sheet Glass Co., Ltd.

[0286] Examples of commercially available colloidal silica include methanol silica sol, IPA-ST, MEK-ST, NBA-ST, XBA-ST, DMAC-ST, ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, and ST-OL, all of which are manufactured by Nissan Chemical Industries, Ltd.

[0287] Surface-modified silica fine particles may also be used, for example, the silica fine particles that have been surface-treated with a reactive silane coupling agent having a hydrophobic group, or modified with a compound having a (meth)acryloyl group. Examples of commercially available powdered silica modified with a compound having a (meth)acryloyl group include Aerosil RM50 and R711 manufactured by Nippon Aerosil Co., Ltd., and examples of commercially available colloidal silica modified with a compound having a (meth)acryloyl group include MIBK-SD manufactured by Nissan Chemical Industries, Ltd.

[0288] The shape of the silica fine particles is not particularly limited, and spherical, hollow, porous, rod-like, plate-like, fibrous, or irregular shapes can be used. The primary particle diameter is preferably in the range of 5 to 200 nm.

[0289] As titanium oxide fine particles, not only extender pigments but also ultraviolet light-responsive photocatalysts can be used, such as anatase titanium oxide, rutile titanium oxide, and brookite titanium oxide. Furthermore, particles designed to respond to visible light by doping different elements into the crystalline structure of titanium oxide can also be used. Anionic elements such as nitrogen, sulfur, carbon, fluorine, and phosphorus, and cationic elements such as chromium, iron, cobalt, and manganese are preferably used as doping elements for titanium oxide. Furthermore, the titanium oxide can be used in the form of a powder, a sol dispersed in an organic solvent or water, or a slurry. Examples of commercially available powdered titanium oxide fine particles include Aerosil P-25 manufactured by Nippon Aerosil Co., Ltd. and ATM-100 manufactured by Teika Co., Ltd. Examples of commercially available slurry-type titanium oxide fine particles include TKD-701 manufactured by Teika Co., Ltd.

[0290] [Fibrous Substrate] The curable resin composition of the present embodiment may further contain a fibrous substrate. The fibrous substrate is not particularly limited, but is preferably one used in fiber-reinforced resins, such as inorganic fibers and organic fibers.

[0291] Examples of inorganic fibers include inorganic fibers such as carbon fibers, glass fibers, boron fibers, alumina fibers, and silicon carbide fibers, as well as carbon fibers, activated carbon fibers, graphite fibers, tungsten carbide fibers, silicon carbide fibers (silicon carbide fibers), ceramic fibers, natural fibers, mineral fibers such as basalt, boron nitride fibers, boron carbide fibers, and metal fibers. Examples of the metal fibers include aluminum fibers, copper fibers, brass fibers, stainless steel fibers, and steel fibers.

[0292] Examples of organic fibers include synthetic fibers made of resin materials such as polybenzazole, aramid, PBO (polyparaphenylene benzoxazole), polyphenylene sulfide, polyester, acrylic, polyamide, polyolefin, polyvinyl alcohol, and polyarylate; natural fibers such as cellulose, pulp, cotton, wool, and silk; and regenerated fibers such as protein, polypeptide, and alginic acid.

[0293] Among these, carbon fiber and glass fiber are preferred because they have a wide range of industrial applications. Of these, only one type may be used, or two or more types may be used simultaneously.

[0294] The fibrous substrate may be an assembly of fibers, with continuous or discontinuous fibers, in the form of a woven or nonwoven fabric, in the form of a fiber bundle in which fibers are aligned in one direction, or in the form of a sheet in which fiber bundles are arranged, or in the form of a three-dimensional shape in which a thickness is added to an assembly of fibers.

[0295] [Dispersion medium] The curable resin composition of the present embodiment may contain a dispersion medium for the purpose of adjusting the solid content and viscosity of the resin composition. The dispersion medium may be any liquid medium that does not impair the effects of the present embodiment, and examples of the dispersion medium include various organic solvents and liquid organic polymers.

[0296] Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK), cyclic ethers such as tetrahydrofuran (THF), and dioxolane, esters such as methyl acetate, ethyl acetate, and butyl acetate, aromatics such as toluene and xylene, and alcohols such as carbitol, cellosolve, methanol, isopropanol, butanol, and propylene glycol monomethyl ether, which can be used alone or in combination. Among these, methyl ethyl ketone is preferred from the viewpoints of volatility during coating and solvent recovery.

[0297] The liquid organic polymer is a liquid organic polymer that does not directly contribute to the curing reaction, and examples thereof include an acrylic polymer (FLOWLEN WK-20: Kyoeisha), an amine salt of a special modified phosphate ester (HIPLAAD ED-251: Kusumoto Chemicals), and a modified acrylic block copolymer (DISPERBYK2000: BYK-Chemie).

[0298] [Other Compounds] The curable resin composition of the present embodiment may contain other compounds, such as a catalyst, a polymerization initiator, an inorganic pigment, an organic pigment, an extender pigment, a clay mineral, a wax, a surfactant, a stabilizer, a flow modifier, a coupling agent, a dye, a leveling agent, a rheology control agent, an ultraviolet absorber, an antioxidant, a flame retardant, a plasticizer, and a reactive diluent.

[0299] A cured product can be obtained by curing the curable resin composition of the present embodiment. When curing, curing may be performed at room temperature or by heating. When performing thermal curing, curing may be performed by a single heating step or by multiple heating steps.

[0300] The curable resin composition of the present embodiment can also be cured by active energy rays. In this case, a photocationic polymerization initiator may be used as the polymerization initiator. Examples of active energy rays that can be used include visible light, ultraviolet light, X-rays, and electron beams.

[0301] Examples of the photocationic polymerization initiator include aryl-sulfonium salts and aryl-iodonium salts, and specifically, arylsulfonium hexafluorophosphate, arylsulfonium hexafluoroantimonate, arylsulfonium tetrakis(pentafluoro)borate, tri(alkylphenyl)sulfonium hexafluorophosphate, etc. The photocationic polymerization initiators may be used alone or in combination of two or more.

[0302] [Method for Preparing Curable Resin Composition] The curable resin composition of the present embodiment can be prepared by uniformly mixing the above-described components, and the method for doing so is not particularly limited. For example, the composition can be prepared by uniformly mixing the components using a pot mill, a ball mill, a bead mill, a roll mill, a homogenizer, a super mill, a homodisper, a universal mixer, a Banbury mixer, a kneader, or the like.

[0303] The curable resin composition of this embodiment is prepared by dissolving the epoxy resin (A) of this embodiment, the epoxy resin (B) of this embodiment, the curable functional group-containing compound (C) of this embodiment, and the thermally expandable particles (D) of this embodiment, as well as the curing agent, filler, fibrous substrate, dispersion medium, and resins other than the various compounds described above, which may be used in combination, in a dispersion medium such as the organic solvent. After dissolution, the solvent is distilled off, and the curable resin composition can be obtained by drying under reduced pressure using a vacuum oven or the like. The curable resin composition of this embodiment may also be in a state in which the constituent materials are uniformly mixed. In this case, uniform mixing is preferably performed using a mixer or the like. The blending ratio of each constituent material can be adjusted appropriately depending on the desired properties of the cured product, such as mechanical strength and heat resistance. The order in which the constituent materials are mixed is not particularly limited when preparing the curable resin composition.

[0304] (Cured Product) The cured product of the present embodiment is obtained by curing the curable resin composition of the present embodiment. The curing method can be appropriately selected and adopted from known methods depending on the properties of the epoxy resin (A), epoxy resin (B), and curable functional group-containing compound (C) used.

[0305] The cured product of the present embodiment is cured by the curable functional group-containing compound (C) of the present embodiment as described above, and therefore exhibits an appropriate crosslink density, thereby maintaining good mechanical strength.

[0306] The structure of the resulting cured product can be confirmed by infrared absorption (IR) spectroscopy using Fourier transform infrared spectroscopy (FT-IR) or the like, elemental analysis, X-ray scattering, or the like.

[0307] A cured product produced from the curable resin composition of the present embodiment has adhesiveness, flexibility, and dismantling properties, and is useful for the following applications.

[0308] The cured curable resin of this embodiment can be laminated with a substrate to form a laminate. The substrate of the laminate can be inorganic materials such as metal and glass, or organic materials such as plastic and wood, as appropriate for the application. The substrate may be in the shape of a laminate, such as a flat plate, a sheet, or a three-dimensional structure, or may be three-dimensional. Any shape depending on the purpose, such as one with cured surface or partial curvature, may be used. There are no limitations on the hardness or thickness of the substrate. A multilayer laminate may also be formed by laminating a first substrate, a layer made of the cured product of the curable resin composition of this embodiment, and a second substrate in this order. Because the curable resin composition of this embodiment has excellent adhesive properties, it can be suitably used as an adhesive for bonding a first substrate and a second substrate. Alternatively, the cured curable resin of this embodiment may be used as a substrate, and the cured product of this embodiment may be further laminated.

[0309] Furthermore, the cured product of the curable resin of this embodiment is capable of relieving stress and is therefore particularly suitable for use in bonding dissimilar materials. For example, even in a laminate in which the substrate is a metal and / or metal oxide and the second substrate is a dissimilar material such as a plastic layer, the adhesive strength is maintained due to the stress relieving ability of the cured product of this embodiment.

[0310] In a laminate obtained by laminating the cured product of this embodiment and a substrate, the layer containing the cured product may be formed by direct coating or molding on the substrate, or an already molded product may be laminated. When directly coating, the coating method is not particularly limited, and examples thereof include spraying, spin coating, dipping, roll coating, blade coating, doctor roll coating, doctor blade coating, curtain coating, slit coating, screen printing, and inkjet printing. When directly molding, examples thereof include in-mold molding, insert molding, vacuum molding, extrusion lamination molding, and press molding. When laminating a molded composition, an uncured or semi-cured composition layer may be laminated and then cured, or a layer containing a cured product obtained by completely curing the composition may be laminated on the substrate. Alternatively, the cured product of this embodiment may be laminated by coating a precursor capable of serving as a substrate and curing it, or the precursor capable of serving as a substrate or the composition of this embodiment may be adhered in an uncured or semi-cured state and then cured. The precursor capable of serving as a substrate is not particularly limited, and examples thereof include various curable resin compositions.

[0311] The cured product obtained using the curable resin composition of this embodiment has particularly high adhesion to metals and / or metal oxides, and therefore can be particularly well used as a primer for metals. Examples of metals include copper, aluminum, gold, silver, iron, platinum, chromium, nickel, tin, titanium, zinc, various alloys, and composite materials thereof, and examples of metal oxides include single oxides and / or composite oxides of these metals. Because the cured product has particularly excellent adhesion to iron, copper, and aluminum, it can be particularly well used as an adhesive for iron, copper, and aluminum.

[0312] The curable resin composition of this embodiment can be suitably used as an adhesive for structural components in the fields of automobiles, trains, civil engineering and construction, electronics, aircraft, and the aerospace industry. Even when used to bond dissimilar materials, such as between metals and non-metals, the adhesive can maintain high adhesion without being affected by changes in temperature environment and is less susceptible to peeling. In addition to structural applications, the adhesive can also be used for general office and medical applications, carbon fiber, and storage battery cells, modules, and cases. It can also be used as a mounting adhesive for bonding optical components, bonding optical disks, mounting printed wiring boards, die bonding adhesives, semiconductor adhesives such as underfills, BGA reinforcing underfills, anisotropic conductive films, anisotropic conductive pastes, and the like.

[0313] When the curable resin composition of this embodiment has a fibrous substrate, and the fibrous substrate is a reinforcing fiber, the curable resin composition containing the fibrous substrate can be used as a fiber-reinforced resin. The method for incorporating the fibrous substrate into the composition is not particularly limited as long as it does not impair the effects of this embodiment, and examples include methods of combining the fibrous substrate and the composition by methods such as kneading, coating, impregnation, injection, and pressure bonding, and can be selected appropriately depending on the form of the fiber and the application of the fiber-reinforced resin.

[0314] The method for molding the fiber-reinforced resin is not particularly limited. To produce a plate-shaped product, extrusion molding is generally used. Plane pressing is also possible. Other methods that can be used include extrusion molding, blow molding, compression molding, vacuum molding, and injection molding. To produce a film-shaped product, a solution casting method can be used in addition to melt extrusion. Examples of melt molding methods include inflation film molding, cast molding, extrusion lamination molding, calendar molding, sheet molding, fiber molding, blow molding, injection molding, rotational molding, and coating molding. In the case of a resin that is cured with active energy rays, a cured product can be produced using various curing methods that use active energy rays. In particular, when a thermosetting resin is used as the main component of the matrix resin, a molding method in which the molding material is made into a prepreg and then pressurized and heated using a press or an autoclave can be mentioned. Other examples include RTM (Resin Transfer Molding) molding, VaRTM (Vacuum Assist Resin Transfer Molding) molding, laminate molding, hand lay-up molding, and the like.

[0315] The curable resin composition of the present embodiment provides a cured product thereof that is excellent in adhesion, flexibility, and ease of disassembly, and can therefore be used as a molding material for large cases, motor housings, casting materials for the inside of cases, gears, pulleys, etc. These may be cured products of the resin alone, or cured products reinforced with fiber such as glass chips.

[0316] Fiber-reinforced resins can be formed into an uncured or semi-cured state known as a prepreg. After distributing the product in the prepreg state, final curing may be performed to form a cured product. When forming a laminate, it is preferable to form the prepreg, then stack other layers, and then perform final curing, since this allows the formation of a laminate in which each layer is in close contact with the others. The mass ratio of the composition and fibrous substrate used in this case is not particularly limited, but it is generally preferable to prepare the prepreg so that the resin content is 20 to 60 mass%.

[0317] The cured product of this embodiment has excellent adhesion, flexibility, and dismantling properties, and can be used as a heat-resistant material and an electronic material. In particular, it can be suitably used for semiconductor encapsulation, circuit boards, build-up films, build-up boards, adhesives, and resist materials. It can also be suitably used as a matrix resin for fiber-reinforced resins, and is particularly suitable as a highly heat-resistant prepreg. The heat-resistant components and electronic components thus obtained can be suitably used for a variety of applications, including, but not limited to, industrial machine parts, general machine parts, automobile, railway, and vehicle parts, aerospace and aviation-related parts, electronic and electrical parts, building materials, containers and packaging materials, household goods, sports and leisure goods, and housing components for wind power generation.

[0318] In particular, taking advantage of the excellent flexibility of the cured product, the adhesive can be suitably used as an adhesive for structural members in the fields of automobiles, trains, civil engineering and construction, electronics, aircraft, and the space industry. Even when used to bond dissimilar materials, such as between metals and non-metals, the adhesive of this embodiment can maintain high adhesion without being affected by changes in the temperature environment, and is less susceptible to peeling. In addition to structural member applications, the adhesive of this embodiment can also be used as an adhesive for general office use, medical use, carbon fiber, storage battery cells, modules, and cases, etc., and examples thereof include adhesives for bonding optical components, adhesives for bonding optical disks, adhesives for mounting printed wiring boards, die bonding adhesives, semiconductor adhesives such as underfills, underfills for reinforcing BGAs, and mounting adhesives such as anisotropic conductive films and anisotropic conductive pastes.

[0319] Furthermore, taking advantage of the excellent dismantling properties of the cured product of this embodiment, an easily dismantlable adhesive material containing the curable resin composition of this embodiment can be used. The easily dismantlable adhesive material is preferably the curable resin composition of this embodiment. A dismantling method using the easily dismantlable adhesive material of this embodiment includes, for example, a bonding step of attaching the easily dismantlable adhesive material to the surface of an adherend and bonding it to the adherend, a curing step of curing the easily dismantlable adhesive material to obtain a cured product, a heat treatment step of performing a heat treatment on the cured product to thermally dissociate the reversible bond contained in either of the general formulas (4-1) and (4-2) derived from the curable functional group-containing compound (C) and expand the heat-expandable particles (D), and a dismantling step of dismantling the adherend and the cured product. Furthermore, a dismantling method using the easily dismantlable adhesive material of the present embodiment may include, for example, a bonding step of attaching the easily dismantlable adhesive material to the surface of an adherend and bonding it to the adherend; a curing step of curing the easily dismantlable adhesive material to obtain a cured product; a heat treatment step of performing a heat treatment on the cured product to thermally dissociate the reversible bond contained in any one of the general formulas (4-1) and (4-2) derived from the curable functional group-containing compound (C) and expand the heat-expandable particles (D); a cooling step of cooling the cured product after the heat treatment to room temperature; and a dismantling step of dismantling the adherend and the cured product.

[0320] Below, we will explain some representative products by giving examples.

[0321] 1. Semiconductor Encapsulating Material A method for obtaining a semiconductor encapsulating material from the curable resin composition of this embodiment includes thoroughly melt-mixing the resin composition, a curing accelerator, and compounding ingredients such as an inorganic filler, as needed, using an extruder, kneader, roll, or the like until uniform. In this process, fused silica is typically used as the inorganic filler. However, when used as a high-thermal-conductivity semiconductor encapsulating material for power transistors and power ICs, highly filled inorganic fillers such as crystalline silica, alumina, and silicon nitride, which have higher thermal conductivity than fused silica, or fused silica, crystalline silica, alumina, and silicon nitride may be used. The inorganic filler is preferably used in a filling rate of 30 to 95% by mass per 100 parts by mass of the curable resin composition. In particular, in order to improve flame retardancy, moisture resistance, and solder crack resistance and to reduce the linear expansion coefficient, 70 parts by mass or more is more preferred, and 80 parts by mass or more is even more preferred.

[0322] 2. Semiconductor Device A semiconductor package molding method for obtaining a semiconductor device from the curable resin composition of this embodiment includes molding the semiconductor encapsulating material using a casting machine, a transfer molding machine, an injection molding machine, or the like, and then heating the molded product at 50 to 250°C for 2 to 10 hours.

[0323] 3. Printed Circuit Board A method for obtaining a printed circuit board from the composition of this embodiment includes laminating the prepreg by a conventional method, appropriately overlaying copper foil, and subjecting the laminate to heat-pressure bonding at 170 to 300°C under a pressure of 1 to 10 MPa for 10 minutes to 3 hours.

[0324] 4. Flexible Substrate An example of a method for producing a flexible substrate from the crosslinkable resin composition of this embodiment is a method comprising the following three steps: The first step is to apply a crosslinkable resin composition containing a resin component, an organic solvent, and the like to an electrically insulating film using a coater such as a reverse roll coater or a comma coater; the second step is to heat the electrically insulating film to which the crosslinkable resin composition has been applied at 60 to 170°C for 1 to 15 minutes using a heater to volatilize the solvent from the electrically insulating film and B-stage the crosslinkable resin composition; and the third step is to thermocompress (preferably a compression pressure of 2 to 200 N / cm and a compression temperature of 40 to 200°C) a metal foil to an adhesive on the electrically insulating film to which the crosslinkable resin composition has been B-staged using a heated roll or the like. If sufficient adhesive performance is obtained by going through the above three steps, the process may be terminated here, but if complete adhesive performance is required, it is preferable to further post-cure the resin composition at 100 to 200° C. for 1 to 24 hours. The thickness of the resin composition layer after final curing is preferably in the range of 5 to 100 μm.

[0325] 5. Build-up Substrates A method for obtaining a build-up substrate from the composition of this embodiment includes, for example, the following steps. First, the composition, containing an appropriate blend of rubber, filler, and the like, is applied to a circuit board on which a circuit has been formed using a spray coating method, curtain coating method, or the like, and then cured (Step 1). Next, if necessary, predetermined through-holes or the like are drilled, the surface is treated with a roughening agent, and the resulting surface is washed with hot water to form irregularities, followed by plating with a metal such as copper (Step 2). These operations are sequentially repeated as desired to alternately build up resin insulating layers and conductor layers of a predetermined circuit pattern (Step 3). Note that drilling of through-holes is performed after the formation of the outermost resin insulating layer. Alternatively, the build-up substrate of this embodiment can be produced by forming a roughened surface by heat-pressing a copper foil, in which the resin composition has been semi-cured on a copper foil, onto a wiring board on which a circuit has been formed, at 170 to 300°C, thereby eliminating the plating step and forming a build-up substrate.

[0326] 6. Build-up Film A build-up film can be obtained from the composition of the present embodiment by applying the composition to the surface of a support film (Y) that is a substrate, and then drying the organic solvent by heating or blowing hot air onto the film to form a layer (X) of the composition.

[0327] The organic solvent used here preferably includes, for example, ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and it is preferable to use the organic solvent in a proportion that results in a nonvolatile content of 30 to 60% by mass.

[0328] The thickness of the layer (X) formed is usually equal to or greater than the thickness of the conductor layer. Since the thickness of the conductor layer of a circuit board is usually in the range of 5 to 70 μm, the thickness of the resin composition layer is preferably 10 to 100 μm. In addition, the layer (X) of the composition in this embodiment may be protected with a protective film described below. Protection with a protective film can prevent adhesion of dust and the like to the surface of the resin composition layer and scratches.

[0329] Examples of the support film and protective film include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate; polycarbonate; polyimide; and even release paper and metal foils such as copper foil and aluminum foil. The support film and protective film may be subjected to a matte treatment, corona treatment, or release treatment. The thickness of the support film is not particularly limited, but is usually 10 to 150 μm, and preferably 25 to 50 μm. The thickness of the protective film is preferably 1 to 40 μm.

[0330] The support film (Y) is peeled off after laminating it onto a circuit board or after forming an insulating layer by heat curing. If the support film (Y) is peeled off after the curable resin composition layer constituting the build-up film is heat cured, adhesion of dust and the like during the curing process can be prevented. When peeling off after curing, the support film is usually subjected to a release treatment in advance.

[0331] A multilayer printed circuit board can be produced using the build-up film obtained as described above. For example, if the layer (X) is protected by a protective film, the protective film is peeled off, and then the layer (X) is laminated to one or both sides of the circuit board so as to be in direct contact with the circuit board, for example, by a vacuum lamination method. The lamination method may be a batch method or a continuous method using a roll. If necessary, the build-up film and the circuit board may be heated (preheated) before lamination. The lamination conditions are preferably a pressure bonding temperature (lamination temperature) of 70 to 140°C and a pressure bonding pressure of 1 to 11 kgf / cm. ２ (9.8 x 10 ４ ~107.9 x 10 ４ N / m ２ ), and lamination is preferably carried out under reduced air pressure of 20 mmHg (26.7 hPa) or less.

[0332] 7. Conductive Paste A conductive paste can be obtained from the curable resin composition of this embodiment by, for example, dispersing conductive particles in the composition. Depending on the type of conductive particles used, the conductive paste can be a paste resin composition for circuit connection or an anisotropic conductive adhesive.

[0333] The present invention will now be described in more detail with reference to examples and comparative examples, in which "parts" and "%" are by mass unless otherwise specified. The present invention is not limited thereto.

[0334] １ H and １３ C-NMR, FD-MS spectrum, and GPC were measured under the following conditions.

[0335] ​​１ H-NMR: JEOL RESONANCE "JNM-ECA600" Magnetic field strength: 600 MHz Number of accumulations: 32 Solvent: DMSO-d ６ Sample concentration: 30% by mass

[0336] １３ C-NMR: "JNM-ECA600" manufactured by JEOL RESONANCE Magnetic field strength: 150 MHz Number of integrations: 320 times Solvent: DMSO-d ６ Sample concentration: 30% by mass

[0337] FD-MS: "JMS-T100GC AccuTOF" manufactured by JEOL Ltd. Measurement range: m / z = 50.00 to 2000.00 Rate of change: 25.6 mA / min Final current value: 40 mA Cathode voltage: -10 kV

[0338] GPC: "HLC-8320GPC" manufactured by Tosoh Corporation Column: "TSK-GEL G2000HXL" + "TSK-GEL G3000HXL" + "TSK-GEL G4000HXL" manufactured by Tosoh Corporation Detector: RI (differential refractometer) Measurement conditions: 40°C Mobile phase: tetrahydrofuran Flow rate: 1 ml / min Standard: "PStQuick A", "PStQuick B", "PStQuick E", "PStQuick F" manufactured by Tosoh Corporation

[0339] The epoxy equivalent of the synthesized epoxy resin was measured in accordance with JIS K7236, and the epoxy equivalent (g / eq) was calculated.

[0340] The number of repeating units can be calculated, for example, from the results of GPC molecular weight measurement, or various appropriate instrumental analyses such as FD-MS and NMR.

[0341] ​Synthesis Example 1: 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g / eq) and 240 g (2.1 equivalents) of bisphenol A (hydroxyl equivalent 114 g / eq) were charged into a flask equipped with a thermometer, a condenser, and a stirrer. The temperature was raised to 140°C over 30 minutes, and then 6.6 g of a 20% aqueous sodium hydroxide solution was charged. The temperature was then raised to 150°C over 30 minutes, and the mixture was further reacted at 150°C for 16 hours. Thereafter, a neutralizing amount of sodium phosphate was added, and 646 g of a hydroxy compound (Ph-1) was obtained. This hydroxy compound (Ph-1) was confirmed to contain the target hydroxy compound because a peak of M+ = 771, corresponding to the theoretical structure of m = 1 in the following structural formula (Ph-1), was obtained in the mass spectrum. The hydroxyl equivalent of this hydroxy compound (Ph-1) calculated by GPC was 2053 g / eq, and the average value of the repeating unit m was 6.9.

[0342]

[0343] Synthesis Example 2 The reaction was carried out in the same manner as in Synthesis Example 1, except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (epoxy equivalent 210 g / eq) in Synthesis Example 1 was changed to 472 g (2.0 equivalents) of 1,15-pentadecanediol diglycidyl ether (epoxy equivalent 236 g / eq), yielding 697 g of hydroxy compound (Ph-2). Mass spectrometry of this hydroxy compound (Ph-2) yielded a peak of M+ = 813, which corresponds to the theoretical structure in which m = 1 in the following structural formula (Ph-2), confirming that it contained the target hydroxy compound. The hydroxyl group equivalent of this hydroxy compound (Ph-2) calculated by GPC was 2226 g / eq, and the average value of the repeating unit m was 6.8.

[0344]

[0345] Synthesis Example 3 The same reaction as in Synthesis Example 1 was carried out, except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (epoxy equivalent 210 g / eq) in Synthesis Example 1 was replaced with 380 g (2.0 equivalents) of 1,9-nonanediol diglycidyl ether (epoxy equivalent 190 g / eq), to obtain 607 g of hydroxy compound (Ph-3). Mass spectrometry of this hydroxy compound (Ph-3) yielded a peak at M+ = 729, which corresponds to the theoretical structure in which m = 1 in the following structural formula (Ph-3), confirming that it contained the target hydroxy compound. The hydroxyl group equivalent of this hydroxy compound (Ph-3) calculated by GPC was 1989 g / eq, and the average value of the repeating unit m was 7.2.

[0346]

[0347] Synthesis Example 4 The same reaction as in Synthesis Example 1 was carried out, except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g / eq) and 240 g (2.1 equivalents) of bisphenol A (hydroxyl equivalent 114 g / eq) in Synthesis Example 1 were changed to 962 g (2.0 equivalents) of polypropylene glycol diglycidyl ether (manufactured by Nagase ChemteX Co., Ltd.: epoxy equivalent 481 g / eq) and 274 g (2.4 equivalents) of bisphenol A (hydroxyl equivalent 114 g / eq), to obtain 1211 g of a hydroxy compound (Ph-4). This hydroxy compound (Ph-4) was confirmed to contain the target hydroxy compound because a peak at M+ = 1226 was obtained in mass spectrum, which corresponds to the theoretical structure of the following structural formula (Ph-4) in which m = 1 and n2 = 11. The hydroxyl equivalent of this hydroxy compound (Ph-4) calculated by GPC was 1582 g / eq, and the average value of the repeating unit m was 3.3.

[0348]

[0349] Synthesis Example 5 The same reaction as in Synthesis Example 1 was carried out, except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g / eq) and 240 g (2.1 equivalents) of bisphenol A (hydroxyl equivalent 114 g / eq) in Synthesis Example 1 were changed to 890 g (2.0 equivalents) of polytetramethylene glycol diglycidyl ether ("Denacol EX-991L" manufactured by Nagase ChemteX: epoxy equivalent 445 g / eq) and 274 g (2.4 equivalents) of bisphenol A (hydroxyl equivalent 114 g / eq), to obtain 1,140 g of a hydroxy compound (Ph-5). This hydroxy compound (Ph-5) was confirmed to contain the target hydroxy compound because a peak at M+ = 1380 was obtained in mass spectrum, which corresponds to the theoretical structure of the following structural formula (Ph-5) in which m = 1 and n2 = 11. The hydroxyl group equivalent of this hydroxy compound (Ph-5) calculated by GPC was 2520 g / eq, and the average value of the repeating unit m was 5.1.

[0350]

[0351] Synthesis Example 6 The same reaction as in Synthesis Example 1 was carried out, except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g / eq) and 240 g (2.1 equivalents) of bisphenol A (hydroxyl equivalent 114 g / eq) in Synthesis Example 1 were changed to 126.2 g (0.39 mol) of 1,6-hexanediol diglycidyl ether ("SR-16H" manufactured by Sakamoto Yakuhin Co., Ltd.: epoxy equivalent 160 g / eq), 78.1 g (0.08 mol) of polypropylene glycol diglycidyl ether ("Denacol EX-931" manufactured by Nagase ChemteX Co., Ltd.: epoxy equivalent 481 g / eq), and 114.6 g (0.50 mol) of bisphenol A (hydroxyl equivalent 114 g / eq), thereby obtaining 317 g of a hydroxy compound (Ph-6). This hydroxy compound (Ph-6) was confirmed to contain the target hydroxy compound because a peak at M+ = 1684 was obtained in the mass spectrum, which corresponds to the theoretical structure of the following structural formula (Ph-6) in which m1 = 1, m2 = 1, and n2 = 11. The hydroxyl equivalent of this hydroxy compound (Ph-6) calculated by GPC was 1597 g / eq.

[0352]

[0353] Synthesis Example 7 The same reaction as in Synthesis Example 1 was carried out, except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g / eq) and 240 g (2.1 equivalents) of bisphenol A (hydroxyl equivalent 114 g / eq) in Synthesis Example 1 were changed to 136 g (0.43 mol) of 1,6-hexanediol diglycidyl ether ("SR-16H" manufactured by Sakamoto Yakuhin Co., Ltd.: epoxy equivalent 160 g / eq), 66 g (0.07 mol) of polytetramethylene glycol diglycidyl ether ("Denacol EX-991L" manufactured by Nagase ChemteX Co., Ltd.: epoxy equivalent 445 g / eq), and 119.7 g (0.53 mol) of bisphenol A (hydroxyl equivalent 114 g / eq), and 318 g of a hydroxy compound (Ph-7) was obtained. This hydroxy compound (Ph-7) was confirmed to contain the target hydroxy compound because a peak at M+ = 1839 was obtained in mass spectrum, which corresponds to the theoretical structure of the following structural formula (Ph-7) in which m1 = 1, m2 = 1, and n2 = 11. The hydroxyl equivalent of this hydroxy compound (Ph-7) calculated by GPC was 1896 g / eq.

[0354]

[0355] Synthesis Example 8: 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (manufactured by Yokkaichi Synthetic Co., Ltd.: epoxy equivalent 210 g / eq) and 456 g (4.0 equivalents) of bisphenol A (hydroxyl equivalent 114 g / eq) were charged into a flask equipped with a thermometer, a condenser, and a stirrer. The temperature was raised to 140°C over 30 minutes, and then 4.0 g of a 4% aqueous sodium hydroxide solution was charged. The temperature was then raised to 150°C over 30 minutes, and the mixture was further reacted at 150°C for 6 hours. Thereafter, a neutralizing amount of sodium phosphate was added, and 858 g of hydroxy compound (Ph-8) was obtained. This hydroxy compound (Ph-8) was confirmed to contain the target hydroxy compound because a peak of M+ = 771 was obtained in the mass spectrum, which corresponds to the theoretical structure of m = 1 in the following structural formula (Ph-8). The hydroxyl equivalent of this hydroxy compound (Ph-8) calculated by GPC was 388 g / eq.

[0356]

[0357] Synthesis Example 9: The reaction was carried out in the same manner as in Synthesis Example 8, except that 420 g (2.0 equivalents) of 1,12-dodecanediol diglycidyl ether (epoxy equivalent 210 g / eq) in Synthesis Example 8 was replaced with 962 g (2.0 equivalents) of polypropylene glycol diglycidyl ether (Nagase ChemteX Corporation's "Denacol EX-931": epoxy equivalent 481 g / eq), to obtain 1390 g of hydroxy compound (Ph-9). Mass spectrometry of this hydroxy compound (Ph-9) yielded a peak at M+ = 1226, corresponding to the theoretical structure of the following structural formula (Ph-9) where m = 1 and n2 = 11, confirming that it contained the target hydroxy compound. The hydroxyl equivalent of this hydroxy compound (Ph-9) calculated by GPC was 593 g / eq.

[0358]

[0359] Synthesis Example 10: In a flask equipped with a thermometer, dropping funnel, condenser, and stirrer, 205.3 g of the hydroxy compound (Ph-1) obtained in Synthesis Example 1, 647.5 g (7.0 mol) of epichlorohydrin, and 150 g of n-butanol were added and dissolved while purging with nitrogen gas. The mixture was then heated to 65°C, reduced pressure to an azeotropic pressure, and 10.6 g (0.13 mol) of a 49% aqueous sodium hydroxide solution was added dropwise over 5 hours. Stirring was then continued under the same conditions for 0.5 hours. During this time, the distillate distilled by azeotropy was separated using a Dean-Stark trap, the aqueous layer was removed, and the reaction was continued while the oil layer was returned to the reaction system. Unreacted epichlorohydrin was then removed by vacuum distillation. 200 g of methyl isobutyl ketone and 100 g of n-butanol were added to the obtained crude epoxy resin and dissolved. To this solution, 15.0 g of a 10% aqueous solution of sodium hydroxide was added, and the mixture was allowed to react at 80°C for 2 hours. The mixture was then washed three times with 100 g of water until the pH of the washings became neutral. The system was then dehydrated by azeotropy, and after microfiltration, the solvent was distilled off under reduced pressure to obtain 235 g of epoxy resin (Ep-1). The epoxy equivalent of the resulting epoxy resin (Ep-1) was 2320 g / eq. Mass spectrometry revealed a peak at M+ = 883, which corresponds to the theoretical structure of the following structural formula (Ep-1): m = 1, q = 1, p1 = 0, and p2 = 0. This confirmed the epoxy resin contained the target epoxy resin (Ep-1).

[0360]

[0361] Synthesis Example 11: The same reaction as in Synthesis Example 10 was carried out, except that 222.6 g of hydroxy compound (Ph-2) was used instead of 205.3 g of hydroxy compound (Ph-1) in Synthesis Example 10, to obtain 251 g of epoxy resin (Ep-2). The epoxy equivalent of the obtained epoxy resin (Ep-2) was 2510 g / eq. Mass spectrometry showed a peak at M+ = 925, which corresponds to the theoretical structure of the following structural formula (Ep-2) in which m = 1, p1 = 0, p2 = 0, and q = 1, and it was therefore confirmed that the epoxy resin contained the target epoxy resin (Ep-2).

[0362]

[0363] Synthesis Example 12: The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 198.9 g of the hydroxy compound (Ph-3), to obtain 229 g of epoxy resin (Ep-3). The epoxy equivalent of the obtained epoxy resin (Ep-3) was 2250 g / eq. Mass spectrometry showed a peak at M+ = 841, which corresponds to the theoretical structure of the following structural formula (Ep-3) in which m = 1, p1 = 0, p2 = 0, and q = 1, and it was therefore confirmed that the epoxy resin contained the target epoxy resin (Ep-3).

[0364]

[0365] Synthesis Example 13: The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 158.2 g of the hydroxy compound (Ph-4), to obtain 193 g of epoxy resin (Ep-4). The epoxy equivalent of the obtained epoxy resin (Ep-4) was 1802 g / eq. Mass spectrometry showed a peak at M+ = 1336, which corresponds to the theoretical structure of the following structural formula (Ep-4) in which m = 1, n2 = 11, p1 = 0, p2 = 0, and q = 1, confirming that the epoxy resin contained the target epoxy resin (Ep-4).

[0366]

[0367] Synthesis Example 14: The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was replaced with 252.0 g of the hydroxy compound (Ph-5), to obtain 277 g of epoxy resin (Ep-5). The epoxy equivalent of the obtained epoxy resin (Ep-5) was 2834 g / eq. Mass spectrometry showed a peak at M+ = 1492, which corresponds to the theoretical structure of the following structural formula (Ep-5) in which m = 1, n2 = 11, p1 = 0, p2 = 0, and q = 1, confirming that the epoxy resin contained the target epoxy resin (Ep-5).

[0368]

[0369] Synthesis Example 15: The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 198.4 g of the hydroxy compound (Ph-6), to obtain 229 g of epoxy resin (Ep-6). The epoxy equivalent of the obtained epoxy resin (Ep-6) was 2244 g / eq. Mass spectrometry showed a peak at M+ = 1796, which corresponds to the theoretical structure of the following structural formula (Ep-6) in which m1 = 1, m2 = 2, n2 = 11, p1 = 0, p2 = 0, and q = 1, confirming that the epoxy resin contained the target epoxy resin (Ep-6).

[0370]

[0371] Synthesis Example 16: The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 191.4 g of the hydroxy compound (Ph-7), to obtain 223 g of epoxy resin (Ep-7). The epoxy equivalent of the obtained epoxy resin (Ep-7) was 2167 g / eq. Mass spectrometry showed a peak at M+ = 1951, which corresponds to the theoretical structure of the following structural formula (Ep-7) in which m1 = 1, m2 = 2, n2 = 11, p1 = 0, p2 = 0, and q = 1, confirming that the epoxy resin contained the target epoxy resin (Ep-7).

[0372]

[0373] Synthesis Example 17: The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 388 g of the hydroxy compound (Ph-8), to obtain 399 g of epoxy resin (Ep-8). The epoxy equivalent of the obtained epoxy resin (Ep-8) was 488 g / eq. Mass spectrometry showed a peak of M+ = 883, which corresponds to the theoretical structure of the following structural formula (Ep-8) in which m = 1, p1 = 0, p2 = 0, and q = 1, and it was therefore confirmed that the epoxy resin contained the target epoxy resin (Ep-8).

[0374]

[0375] Synthesis Example 18: The same reaction as in Synthesis Example 10 was carried out, except that 205.3 g of the hydroxy compound (Ph-1) in Synthesis Example 10 was changed to 593 g of the hydroxy compound (Ph-9), to obtain 584 g of epoxy resin (Ep-9). The epoxy equivalent of the obtained epoxy resin (Ep-9) was 714 g / eq. Mass spectrometry showed a peak at M+ = 1336, which corresponds to the theoretical structure of the following structural formula (Ep-9) in which m = 1, p1 = 0, p2 = 0, and q = 1, and it was therefore confirmed that the epoxy resin contained the target epoxy resin (Ep-9).

[0376] Synthesis Example 19: In a flask equipped with a thermometer, dropping funnel, condenser, and stirrer, 48.8 g (epoxy equivalent: 488 g / eq) of the epoxy resin (EP-8) obtained in Synthesis Example 17 and 19.6 g (0.2 mol) of furfuryl alcohol were added and dissolved while purging with nitrogen gas. Then, 0.7 g (0.007 mol) of triethylamine was added, and the mixture was heated to 70°C over 30 minutes and further reacted at 70°C for 9 hours. The mixture was then heated to 150°C, and excess furfuryl alcohol was distilled off under reduced pressure to obtain 53 g of furan compound (F-1). The molecular weight of this furan compound (F-1) measured by GPC was Mn = 1600 and Mw = 4900. The molecular weight per mole of furan structure of this furan compound (F-1) calculated from 1H-NMR was 575 g / eq.

[0377]

[0378] Synthesis Example 20 A flask equipped with a thermometer, a stirrer, and a condenser was charged with 29 g of the furan compound (F-1, furan equivalent: 575 g / eq) obtained in Synthesis Example 19, 5.3 g of 1,6'-bismaleimide-(2,2,4-trimethyl)hexane (BMI-THM manufactured by Daiwa Chemical Industry Co., Ltd.), and 50 g of toluene. After purging with nitrogen, the mixture was reacted at 60°C for 20 hours. Thereafter, the toluene was distilled off under reduced pressure to obtain 34 g of furan compound (F-2). The molecular weights measured by GPC were Mn = 2000 and Mw = 7900. １The molecular weight per mole of the furan structure calculated from H-NMR was 2043 g / eq. In the following chemical formulas spanning two or more lines, * indicates a direct bond to the position of * on the next line.

[0379]

[0380] Synthesis Example 21 The same reaction as in Synthesis Example 19 was carried out, except that 48.8 g (epoxy equivalent 488 g / eq) of epoxy resin (Ep-8) in Synthesis Example 19 was changed to 71.4 g (epoxy equivalent 714 g / eq) of epoxy resin (Ep-9), to obtain 73 g of furan compound (F-3). The molecular weight of this furan compound (F-3) measured by GPC was Mn = 1900 and Mw = 5100. １ The molecular weight per mole of furan structure calculated from H-NMR was 796 g / eq.

[0381]

[0382] Synthesis Example 22 The same reaction as in Synthesis Example 20 was carried out, except that 29 g of the furan compound (F-1, furan equivalent 575 g / eq) in Synthesis Example 20 was changed to 40 g of the furan compound (F-3, furan equivalent 796 g / eq), to obtain 46 g of a furan compound (F-4). The molecular weights measured by GPC were Mn = 2,300 and Mw = 9,000. １ The molecular weight per mole of furan structure calculated from H-NMR was 2706 g / eq.

[0383]

[0384] Synthesis Example 23 The same reaction as in Synthesis Example 20 was carried out, except that the amount of 1,6'-bismaleimide-(2,2,4-trimethyl)hexane (BMI-THM manufactured by Daiwa Chemical Industry Co., Ltd.) was changed from 5.3 g to 11.9 g, to obtain 41 g of maleimide compound (M-1). The molecular weights measured by GPC were Mn = 2300 and Mw = 9000. The molecular weight per mole of maleimide structure calculated by 1H-NMR was 1627 g / eq.

[0385]

[0386] Synthesis Example 24 A flask equipped with a thermometer, a stirrer, and a condenser was charged with 34 g of the furan compound (F-2, furan equivalent: 2043 g / eq) obtained in Synthesis Example 20, 3.1 g of N-(4-aminophenyl)maleimide (manufactured by Tokyo Chemical Industry Co., Ltd.), and 50 g of toluene. After purging with nitrogen, the mixture was reacted at 60°C for 12 hours. Thereafter, tetrahydrofuran was distilled off under reduced pressure to obtain 33 g of an amino group-containing compound (D-1). The molecular weights measured by GPC were Mn = 2100 and Mw = 8400. The active hydrogen equivalent calculated by 1H-NMR was 1115 g / eq.

[0387]

[0388] Synthesis Example 25 The same reaction as in Synthesis Example 24 was carried out, except that 34 g of the furan compound (F-2, furan equivalent 2043 g / eq) in Synthesis Example 24 was changed to 45 g of a furan compound (F-4, furan equivalent 2706 g / eq), to obtain 44 g of an amino group-containing compound (D-2). The molecular weights measured by GPC were Mn = 2700 and Mw = 10100. The active hydrogen equivalent calculated by 1H-NMR was 1447 g / eq.

[0389]

[0390] Synthesis Example 26: A flask equipped with a thermometer, a stirrer, and a condenser was charged with 40 g of the maleimide compound (M-1, maleimide equivalent: 1627 g / eq) obtained in Synthesis Example 23, 2.4 g of furfurylamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 50 g of toluene. After purging with nitrogen, the mixture was reacted at 60°C for 12 hours. The toluene was then distilled off under reduced pressure to obtain 38 g of an amino group-containing compound (D-3). The molecular weight measured by GPC was Mn = 2400 and Mw = 9100. The active hydrogen equivalent calculated by 1H-NMR was 862 g / eq.

[0391]

[0392] Synthesis Example 27 The following amino group-containing compound (D-4) was synthesized with reference to the method described in the literature, Macromol. Mater. Eng. 2020,305,2000359. A flask equipped with a thermometer, a stirrer, and a condenser was charged with 18 g of 4,4'-diphenylmethane bismaleimide (BMI-1000 manufactured by Daiwa Chemical Industry Co., Ltd.), 15 g of furfurylamine, and 50 g of toluene. After nitrogen substitution, the mixture was reacted at 60 ° C. for 2 hours. Thereafter, the toluene was distilled off under reduced pressure to obtain 31 g of amino group-containing compound (D-4). Since a peak of M+ = 552 was obtained in the mass spectrum of this amino group-containing compound, it was confirmed that it contained the target amino group-containing compound (D-4).

[0393]

[0394] Synthesis Example 28: A flask equipped with a thermometer, a stirrer, and a condenser was charged with 34 g of the furan compound (F-2, furan equivalent: 2043 g / eq) obtained in Synthesis Example 20, 3.2 g of 4-hydroxyphenylmaleimide (Tokyo Chemical Industry Co., Ltd.), and 50 g of toluene. After purging with nitrogen, the mixture was reacted at 60°C for 12 hours. Tetrahydrofuran was then distilled off under reduced pressure to obtain 33 g of a phenolic hydroxyl group-containing compound (D-5). The molecular weights measured by GPC were Mn = 2200 and Mw = 8300. The hydroxyl group equivalent calculated by 1H-NMR was 2288 g / eq.

[0395]

[0396] Synthesis Example 29 The same reaction as in Synthesis Example 28 was carried out, except that 34 g of the furan compound (F-2, furan equivalent 2043 g / eq) in Synthesis Example 28 was changed to 45 g of the furan compound (F-4, furan equivalent 2706 g / eq), to obtain 44 g of a phenolic hydroxyl group-containing compound (D-6). The molecular weights measured by GPC were Mn = 2700 and Mw = 10100. The hydroxyl group equivalent calculated by 1H-NMR was 2895 g / eq.

[0397]

[0398] Examples 1 to 32 and Comparative Examples 1 to 6 Preparation of Compositions and Cured Products Each compound was used in the formulations shown in Tables 1 and 2 (numbers in the tables are by weight) and mixed uniformly in a mixer (Thinky Corporation's "Awatori Rentaro ARV-200") to obtain a curable resin composition. This curable resin composition was sandwiched between aluminum mirror plates (Engineering Test Service Co., Ltd.'s "JIS H 4000 A1050P") using a silicone tube as a spacer, and heat-cured under specified conditions to obtain a cured product with a thickness of 0.7 mm.

[0399] <Tensile elongation> The cured product was punched into a dumbbell shape (JIS K 7161-2-1BA) using a punching blade to prepare a test specimen. A tensile test of this test specimen was carried out in accordance with JIS K 7162-2 using a tensile tester (Shimadzu Corporation's "Autograph AG-IS") to evaluate the elongation at break in a measurement environment of 23°C (test speed: 2 mm / min).

[0400] <Evaluation of Adhesion and Dismantling Properties> Each compound was used in the formulations shown in Tables 1 and 2 (the numbers in the tables are by weight) and uniformly mixed in a mixer (Thinky Corporation's "Awatori Rentaro ARV-200") to obtain a curable resin composition. This resin composition was applied to one of two cold-rolled steel plates (TP Giken Co., Ltd.'s "SPCC-SD," 1.0 mm x 25 mm x 100 mm), glass beads (Potters Ballotini Co., Ltd.'s "J-80") were added as spacers, and the other SPCC-SD was bonded to the plate (adhesion area: 25 mm x 12.5 mm). This was then heat-cured at the temperatures shown in Tables 1 and 2 to obtain shear test specimens. The test specimens were subjected to a tensile shear test to evaluate adhesion. The test was performed in accordance with JIS K 6850, and the maximum point stress at a measurement environment of 23°C was compared. - Initial adhesive strength: A shear test was conducted on the prepared test specimens without any special treatment. - Adhesion strength after heating: The prepared test specimens were heated in a heating dryer at 200°C for 30 minutes, and then the substrate was cooled to room temperature before a shear test was conducted. - Dismantling evaluation: The strength reduction rate was calculated using "(initial adhesive strength - adhesive strength after heating) / initial adhesive strength x 100". - Dismantling reproducibility evaluation: The standard deviation of "adhesion strength after heating" was evaluated and evaluated according to the following criteria: A: Standard deviation less than 0.5 MPa (very good reproducibility) B: Standard deviation 0.5 MPa or more but less than 1.5 MPa (good reproducibility) C: Standard deviation 1.5 MPa or more (poor reproducibility) -: Strength reduction rate was less than 10%, so no evaluation was conducted (no dismantling function) The maximum point stress was compared in a measurement environment of 23°C.

[0401] <Structural Periodicity> A cross section of the cured resin was prepared using an ultramicrotome, and the structural periodicity was observed using a scanning electron microscope (SEM) so that the contrast of the morphology could be clearly distinguished.

[0402] SEM Model used: JEOL JSM-7800F Acceleration voltage: 5 kV

[0403]

[0404] The formulations shown in the table are as follows: E-850S: Bisphenol A liquid epoxy resin (DIC Corporation, epoxy equivalent 188 g / eq) DICY: Dicyandiamide (DICY7, Mitsubishi Chemical Corporation) DCMU: 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DIC Corporation, B-605-IM) DTA: Diethylenetriamine (Kanto Chemical) F-260D, F-190D: Thermal expansion capsule (Matsumoto Yushi Seiyaku) 953240L: Thermal expansion graphite (Ito Graphite Industries) EXP 50S150: Thermal expansion graphite (Fuji Graphite Industries)

[0405] In Examples 1 to 32, the flexibility, initial adhesive strength, rate of strength reduction upon additional heating, and reproducibility of the disassembly function all showed good results. In this system, the expansion of the expansive material upon heating induces destruction of the adhesive layer and a decrease in the adhesive area at the adhesive layer / substrate interface, so the system exhibits easy disassembly not only during heating but also after returning to room temperature.

[0406] Furthermore, this system has a phase-separated structure, suggesting the possibility that the reversible bonding units are unevenly distributed in the adhesive layer. The uneven distribution of the reversible bonding structures in the flexible sea phase enhances the dissociation effect caused by the Retro-Diels-Alder reaction upon heating. As a result, we speculate that this induces softening and embrittlement of the adhesive layer upon heating, further promoting the expansion effect of the expanding capsules, resulting in improved reproducibility of easy disassembly.

[0407] Comparative Examples 1 and 4 did not exhibit dismantling function because they did not contain an expanding material in their compositions. When heated, reversible bond dissociation (Retro-Diels-Alder reaction) occurs, but the bond is re-formed (Diels-Alder reaction) in the process of cooling to room temperature, which is thought to be why dismantling ability at room temperature was not exhibited.

[0408] In Comparative Examples 2 and 5, the adhesive strength varied greatly when the adherend was further heated, and the disassembly function could not be reproduced. Comparative Examples 2 and 5 did not contain reversible bonds, and it is presumed that the function was not fully realized by the effect of the expanding agent alone.

[0409] The flexibility of the cured product and the initial adhesive strength were very low in Comparative Examples 3 and 6. In the Examples, both flexibility and adhesiveness were achieved due to the phase separation structure of the epoxy resin (A) and the epoxy resin (B), but it is thought that in Comparative Examples 3 and 6, the phase separation structure was not developed, and therefore flexibility and adhesiveness were not achieved.

Claims

1. A curable resin composition comprising: an epoxy resin (A) having an epoxy equivalent of 500 to 10,000 g / eq and represented by the following general formula (1); an epoxy resin (B) having an epoxy equivalent of 100 to 300 g / eq; a curable functional group-containing compound (C) represented by the following general formula (4-1) or (4-2); and thermally expandable particles (D). In the formula (1), each Ar is independently a structure having an aromatic ring having an unsubstituted or substituted group, X is a structural unit represented by the following general formula (2), and Y is a structural unit represented by the following general formula (3): [In the formulas (2) and (3), Ar is the same as defined above, and R １ , R ２ are each independently a hydrogen atom, a methyl group, or an ethyl group; R' is a divalent hydrocarbon group having 2 to 12 carbon atoms; R ３ , R ４ , R ７ , R ８ each independently represents a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group; R ５ , R ６ , R ９ , R １０ are each independently a hydrogen atom or a methyl group, n1 is an integer of 4 to 16, and n2 is the average number of repeating units of 2 to 30. １１ , R １２ are each independently a glycidyl ether group or a 2-methylglycidyl ether group; R １３ , R １４ each independently represents a hydroxyl group, a glycidyl ether group, or a 2-methylglycidyl ether group; R １５ , R １６ are hydrogen atoms or methyl groups, m1, m2, p1, p2, and q are average values ​​of repetition, m1 and m2 are each independently 0 to 25 and m1+m2≧1, p1 and p2 are each independently 0 to 5, and q is 0.5 to 5. However, the bond between X represented by the general formula (2) and Y represented by the general formula (3) may be random or block, and the total number of the structural units X and Y present in one molecule is m1 and m2, respectively. [The furan-derived structures in the formulae (4-1) and (4-2) may have a halogen atom, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amide group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group as a substituent. ａ , n b is the average number of repeats, and each is independently 0 to 10. m is an integer of 1 to 4. Z １ is the following formula (5), Z ２ is any one of the structures represented by the following formulas (6A) and (6B), and Z ３ is any of the structures represented by the following formulas (7-1) to (7-3), and a plurality of such structures in one molecule may be the same or different. [The aromatic ring in formula (5) may be substituted or unsubstituted, * represents a bonding point, Fg is a curable functional group, and -Fg on the naphthalene ring in the formula indicates that it may be bonded to any position.] In formulae (6A) and (6B), each Ar is independently a structure having an unsubstituted or substituted aromatic ring, １ , R ２ are each independently a hydrogen atom, a methyl group, or an ethyl group, R is a hydrogen atom or a methyl group, R' is a divalent hydrocarbon group having 2 to 12 carbon atoms, n1 is an integer from 4 to 16, n2 is the average number of repeating units which is 2 to 30, k1 is the average number of repeating units which is in the range of 0.5 to 5, p1 and p2 are each independently 0 to 5, X is a structural unit represented by the following formula (6-1), and Y is a structural unit represented by the following formula (6-2), [In formula (6-1) (6-2), Ar, R, R １ , R ２ , R', n1, and n2 are the same as above.] m1 and m2 are the average value of the repetition, each independently being 0 to 25, and m1+m2≧1, provided that the bond between the structural unit X represented by formula (6-1) and the structural unit Y represented by formula (6-2) may be random or block, and the total numbers of the structural units X and Y present in one molecule are m1 and m2, respectively.] [In formulas (7-1) to (7-3), n3 and n5 are average numbers of repeating units, each of which is 0.5 to 10, n4 is an integer of 1 to 16, and each R″ is independently a hydrogen atom, a methyl group, or an ethyl group.] 2. The curable resin composition according to claim 1, wherein the curable functional group-containing compound (C) is a hydroxyl group-containing compound or an amine group-containing compound.

3. A curable resin composition according to claim 1 or 2, wherein the concentration of reversible bonds in the curable functional group-containing compound (C) relative to the total mass of the curable components in the curable resin composition is 0.10 mmol / g or more.

4. The curable resin composition according to claim 1 or 2, further comprising a curing agent for epoxy resins other than the curable functional group-containing compound (C).

5. A curable resin composition according to claim 1 or 2, wherein the mass ratio (A):(B) of the epoxy resin (A) to the epoxy resin (B) is 90:10 to 10:

90.

6. The curable resin composition according to claim 1 or 2, wherein the thermally expandable particles (D) are at least one type selected from the group consisting of thermally expandable microcapsules and expandable graphite.

7. A curable resin composition according to claim 1 or 2, wherein the proportion of the thermally expandable particles (D) used is in the range of 3 to 40 parts by mass per 100 parts by mass of the epoxy resin (A) and the epoxy resin (B) combined.

8. A cured product obtained by curing the curable resin composition according to claim 1 or 2.

9. A laminate comprising a substrate and a layer comprising the cured product according to claim 8.

10. A heat-resistant component containing the cured product according to claim 8.

11. A dismantlable adhesive material containing the curable resin composition according to claim 1 or 2.

12. A dismantling method using the dismantlable adhesive material according to claim 11, comprising: a bonding step of adhering the dismantlable adhesive material to a surface of an adherend and bonding it to the adherend; a curing step of curing the dismantlable adhesive material to obtain a cured product; a heat treatment step of subjecting the cured product to a heat treatment to thermally dissociate reversible bonds contained in the general formulae (4-1) and (4-2) derived from the curable functional group-containing compound (C) and expand the heat-expandable particles (D); and a dismantling step of dismantling the adherend and the cured product.

13. The dismantling method according to claim 12, further comprising a cooling step of cooling the heat-treated hardened material to room temperature after the heat treatment step and before the dismantling step.

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