Compound

Abstract

Provided is a compound that has a long working life in a manufacturing process, has little change in characteristics due to heating during molding of a bonded magnet, and has high mechanical strength even when a thermosetting resin is cured under a low temperature condition. This compound contains an epoxy resin (A), metal element-containing particles (C), and a curing agent (D) having an imidazole structure. The curing agent (D) having an imidazole structure contains a compound represented by formula (1) and / or a compound represented by formula (2). R1, R2, X, Y, Z, m and n are as described in the specification.

Description

Compound

[0001] The present invention relates to a compound.

[0002] A bonded magnet is a molded body made by mixing magnetic particles with a binder such as a resin component and processing it into a specific shape. Because bonded magnets contain resin components, they have a high degree of freedom in shape and are more moldable than sintered magnets, so they are increasingly being used in motors for automobiles, general home appliances, communication and audio equipment, medical equipment, general industrial equipment, etc.

[0003] On the other hand, these motors are expected to have higher rotation speeds in anticipation of higher output, and bonded magnets that are subjected to strong centrifugal forces tend to require high mechanical strength to prevent cracking and chipping.

[0004] Patent Document 1 discloses a resin compound for bonded magnets containing an epoxy resin, a curing agent, a curing accelerator, and magnetic powder, in which the accelerator has a borane structure and a borate structure, resulting in a resin compound for bonded magnets with excellent storage stability and mechanical strength.

[0005] Patent Document 2 discloses a method for manufacturing a bonded magnet that contains an epoxy resin, a curing agent, a curing accelerator, and magnetic powder, and uses a solvent, and that has excellent mechanical strength and a long usable life in the manufacturing process because the accelerator and the solvent satisfy a specified composition.

[0006] Patent No. 6606908 Patent No. 6198633

[0007] Bonded magnets are molded using either compression molding or injection molding, and are often molded by applying heat and pressure to a composite material called a "compound" made by mixing magnetic particles with binders such as resin components. Compounds for compression molding use thermosetting resin as the resin component, which gives them excellent heat resistance, but the curing reaction of the resin component progresses during compound production and bonded magnet molding, which often poses issues with the usable time during the manufacturing process and a decline in the properties of the bonded magnet.

[0008] Furthermore, compression molding requires heating to accelerate the curing reaction of the thermosetting resin, but the magnetic particles in the compound are sensitive to heat, and in a heated environment the surfaces of the magnetic particles are oxidized, easily resulting in a deterioration of the magnetic properties.

[0009] Therefore, there is a demand for a compound for bonded magnets that has high mechanical strength and can prevent cracking of the bonded magnet even when the thermosetting resin is reacted under low temperature conditions (for example, 150°C or less).

[0010] In contrast, compounds for bonded magnets that contain curing accelerators with borane and borate structures, as in Patent Document 1, have a certain effect on the usable time during the manufacturing process and on reducing the deterioration of the bonded magnet's properties, but there is room for improvement in mechanical strength when the thermosetting resin is cured under lower temperature conditions.

[0011] Furthermore, bonded magnet compounds produced using a manufacturing method in which the accelerator and solvent satisfy a specified composition, as in Patent Document 2, have a certain effect on the usable time during the manufacturing process and on reducing the deterioration of the bonded magnet's properties, but when the thermosetting resin is subjected to a curing reaction under lower temperature conditions, there is room for improvement in mechanical strength.

[0012] The problem that the present invention aims to solve is to provide a bonded magnet compound that has a long usable life in the manufacturing process, that changes in properties little when heated during bonded magnet molding, and that retains high mechanical strength even when the thermosetting resin is cured under low-temperature conditions.

[0013] As a result of extensive research into solving the above-mentioned problems, the inventors discovered that the above-mentioned problems of the conventional technology can be solved by containing an epoxy resin, a curing agent, magnetic particles, and a curing accelerator, and by the curing accelerator satisfying a specified composition, and thus completed the present invention.

[0014] That is, the present invention includes the following aspects: <1> A compound containing an epoxy resin (A), metal element-containing particles (C), and a curing agent (D) having an imidazole structure, wherein the curing agent (D) having an imidazole structure contains a compound represented by the following formula (1) and / or a compound represented by the following formula (2):

[0015]

[0016]

[0017] (In formulas (1) and (2), R １ and R ２ are each independently any one selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, and a cycloalkyl group having 6 to 20 carbon atoms which may have a substituent. １ and R ２ may be the same or different, and R １ and R ２may be bonded to form a non-aromatic fused ring. X is any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aralkyl group having 7 to 20 carbon atoms which may have a substituent, and a heteroarylalkyl group having 4 to 20 carbon atoms which may have a substituent. Y and Z are each independently any one selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and an acyl group having 1 to 20 carbon atoms which may have a substituent. Y and Z may be the same or different, and two or more Ys or two or more Zs may be bonded to form a monocyclic or fused ring. and m and n each independently represent an integer of 1 to 4.) <2> The compound according to <1>, wherein in the curing agent (D) having an imidazole structure, Y and Z each independently represent one selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxyl group, an alkoxy group having 1 to 20 carbon atoms without a substituent, an alkyl group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, an alkoxy group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, an aryl group having 6 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, an aryloxy group having 6 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, and an acyl group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent.<3> In the curing agent (D) having an imidazole structure, the compound represented by formula (1) is any one selected from the group consisting of 2-(2-hydroxyphenyl)imidazole, 2-(2-hydroxyphenyl)-4(5)-methylimidazole, 4-ethyl-(2-hydroxyphenyl)-5-methylimidazole, (2-hydroxyphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-(2-hydroxyphenyl)-5-methylimidazole, and 2-(2-hydroxy-3(5)-methoxyphenyl)imidazole, and / or the compound represented by formula (2) is The compound according to <1> or <2>, wherein the metal element-containing particles (C) are any one selected from the group consisting of 2-(2-hydroxyphenyl)benzimidazole, 2-(2-hydroxy-3(5)-methoxyphenyl)benzimidazole, 2-(1-hydroxynaphthalen-2-yl)benzimidazole, 2-(2-hydroxynaphthalen-1-yl)benzimidazole, and 2-(2-hydroxyphenyl)benzimidazole-6-carboxylic acid. <4> The compound according to <1> or <2>, further comprising a curing agent (B) different from the curing agent having an imidazole structure. <5> The compound according to <4>, wherein the curing agent (B) different from the curing agent having an imidazole structure includes a curing agent that is solid at room temperature (25°C), and the content of the curing agent that is solid at room temperature (25°C) is 50 mass% or more relative to the total amount of the curing agents. <6> The compound according to <1> or <2>, wherein the metal element-containing particles (C) are magnetic particles. <7> The compound according to <6>, wherein the magnetic particles are rare earth magnetic particles. <8> The compound according to <6>, wherein the content of the magnetic particles is 70% by mass or more and 99.5% by mass or less relative to the total mass of the compound. <9> The specific surface area of ​​the magnetic particles is 0.005 m. ２ / g or more 5.0m ２ / g or less. <10> The compound according to <6>, wherein (X) is the content (mass%) of the magnetic particles relative to the total mass of the compound, (Y) is the specific surface area of ​​the magnetic particles, and (Z) is the content (mass%) of the curing agent (D) having an imidazole structure relative to the total mass of the compound, and (X), (Y), and (Z) satisfy the following formula (γ): 0.000010≦(Z) / (X)×(Y)≦0.30 (γ) <11> The compound according to <1>, wherein the epoxy resin (A) contains a partial structure represented by the following formula (A1):

[0018]

[0019] (In formula (A1), R １ ~R ３ are each independently a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a heteroatom, or a substituent containing a halogen atom, and R １ ~R ３ At least one of the groups R １ ~R ３ may be the same or different.) <12> The compound according to <1>, wherein the epoxy resin (A) contains a partial structure represented by the following formula (A2):

[0020]

[0021] (In formula (A2), R １ , R ２ is an alkylene group having 1 to 12 carbon atoms, and m and n are each independently an integer of 1 or more. １ and G ２ is one selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a hetero atom, and a substituent containing a halogen atom. １ and G ２may be the same or different.) <13> The compound according to <1> or <2>, wherein the epoxy resin (A) contains an epoxy resin that is solid at room temperature (25°C), and the content of the epoxy resin that is solid at room temperature (25°C) is 50 mass% or more based on the total amount of the epoxy resins. <14> The compound according to <1> or <2>, further containing a compound (E) represented by the following formula (3):

[0022]

[0023] In formula (3), R １ ~R ８ R is independently one selected from the group consisting of hydrogen, an alkyl group, an aromatic group, a substituent containing a hetero atom, and a substituent containing a halogen atom. １ ~R ８ may be the same or different. ４ ~R ８ At least two selected from the group consisting of: may form a ring and form a condensed ring with an adjacent benzene ring. <15> A varnish comprising an epoxy resin (A), a curing agent (D) having an imidazole structure, a curing agent (B) different from the curing agent having an imidazole structure, and an organic solvent (G), wherein the curing agent (D) having an imidazole structure comprises a compound represented by the following formula (1) and / or a compound represented by the following formula (2):

[0024]

[0025]

[0026] (In formulas (1) and (2), R １ and R ２ are each independently any one selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, and a cycloalkyl group having 6 to 20 carbon atoms which may have a substituent. １ and R ２ may be the same or different, and R １ and R ２may be bonded to form a non-aromatic fused ring. X is any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aralkyl group having 7 to 20 carbon atoms which may have a substituent, and a heteroarylalkyl group having 4 to 20 carbon atoms which may have a substituent. Y and Z are each independently any one selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and an acyl group having 1 to 20 carbon atoms which may have a substituent. Y and Z may be the same or different, and two or more Ys or two or more Zs may be bonded to form a monocyclic or fused ring. m and n each independently represent an integer of 1 to 4. <16> A bonded magnet obtained by molding and curing the compound according to any one of <1> to <16>. <17> A motor including the bonded magnet according to <16>.

[0027] According to the present invention, it is possible to provide a compound that has a long usable time in the manufacturing process, exhibits little change in properties due to heating during bonded magnet molding, and has high mechanical strength even when the thermosetting resin is cured under low temperature conditions.

[0028] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the following present embodiment is an example for explaining the present invention, and the present invention is not limited to the following embodiment. The present invention can be carried out with appropriate modifications within the scope of its gist. In this embodiment, a numerical range indicated using "to" means a range that includes the numerical values ​​described before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this embodiment, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the Examples. In this embodiment, a combination of two or more preferred aspects is a more preferred aspect. In this embodiment, when multiple substances corresponding to each component are present, the amount of each component refers to the total amount of the multiple substances, unless otherwise specified.

[0029] Bonded Magnet Compound The compound of this embodiment contains an epoxy resin (A), metal element-containing particles (C), and a curing agent (D).

[0030] The mixture of epoxy resin (A) and curing agent (D) (hereinafter simply referred to as the "resin composition") undergoes a curing reaction upon heat treatment, forming three-dimensional crosslinks around the metal element-containing particles (C), resulting in a bonded magnet cured product with high mechanical strength.

[0031] <Epoxy Resin (A)> The compound of the present embodiment contains an epoxy resin.

[0032] The epoxy resin is not limited to the following, but examples thereof include novolac type epoxy resins such as biphenyl type epoxy resins, stilbene type epoxy resins, diphenylmethane type epoxy resins, sulfur atom-containing epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, biphenyl novolac type epoxy resins, and naphthol novolac type epoxy resins, dicyclopentadiene type epoxy resins, salicylaldehyde type epoxy resins such as salicylaldehyde novolac type epoxy resins, copolymer type epoxy resins of naphthols and phenols, epoxidized products of aralkyl type phenolic resins, bisphenol type epoxy resins, glycidyl ether type epoxy resins of alcohols, paraxylylene and / or metaxylylene modified phenols, Examples of such epoxy resins include glycidyl ether type epoxy resins of phenolic resins, glycidyl ether type epoxy resins of terpene-modified phenolic resins, cyclopentadiene type epoxy resins, glycidyl ether type epoxy resins of polycyclic aromatic ring-modified phenolic resins, glycidyl ether type epoxy resins of naphthalene ring-containing phenolic resins, glycidyl ester type epoxy resins, glycidyl or methylglycidyl type epoxy resins, alicyclic type epoxy resins, halogenated phenol novolac type epoxy resins, hydroquinone type epoxy resins, trimethylolpropane type epoxy resins, linear aliphatic epoxy resins obtained by oxidizing an olefin bond with a peracid such as peracetic acid, epoxy resins containing a partial structure represented by the following formula (A1), and epoxy resins containing a partial structure represented by the following formula (A2). These may be used alone or in combination of two or more. (In formula (A1), R １ ~R ３ are each independently a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a heteroatom, or a substituent containing a halogen atom, and R １ ~R ３ At least one of the groups R １ ~R ３ may be the same or different from each other. (In formula (A2), R １ , R ２is an alkylene group having 1 to 12 carbon atoms, and m and n are each independently an integer of 1 or more. １ and G ２ is one selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a hetero atom, and a substituent containing a halogen atom. １ and G ２ may be the same or different.)

[0033] From the viewpoint of increasing the mechanical strength of the bonded magnet, the epoxy resin preferably contains at least one selected from the group consisting of biphenyl-type epoxy resins, orthocresol novolac-type epoxy resins, phenol novolac-type epoxy resins, biphenyl novolac-type epoxy resins, salicylaldehyde novolac-type epoxy resins, naphthol novolac-type epoxy resins, epoxy resins containing a partial structure represented by the following formula (A1), and epoxy resins containing a partial structure represented by the following formula (A2). Of these, it is more preferable to contain at least one selected from the group consisting of epoxy resins containing a partial structure represented by the following formula (A1) and epoxy resins containing a partial structure represented by the following formula (A2). (In formula (A1), R １ ~R ３ are each independently a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a heteroatom, or a substituent containing a halogen atom, and R １ ~R ３ At least one of the groups R １ ~R ３ may be the same or different from each other. (In formula (A2), R １ , R ２ is an alkylene group having 1 to 12 carbon atoms, and m and n are each independently an integer of 1 or more. １ and G ２ is one selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a hetero atom, and a substituent containing a halogen atom. １ and G ２ may be the same or different.)

[0034] R １ and R ２ The alkylene group having 1 to 12 carbon atoms in the formula (I) may be linear or branched, and the number of carbon atoms in the alkylene group is preferably 1 to 10, more preferably 1 to 6. Examples of the alkylene group having 1 to 12 carbon atoms include -CH ２ -, -CH ２ -CH ２ -, -CH(CH ３ ) -, -CH ２ -CH ２ -CH ２ -, -CH ２ -CH(CH ３ ) -, -CH(CH ３ )-CH ２ -, -C(CH ３ ) ２ --etc.

[0035] G １ and G ２ The alkyl group in the formula (I) may be linear or branched, and the number of carbon atoms in the alkyl group is preferably 1 to 18, more preferably 1 to 15, and even more preferably 1 to 10. Examples of the alkyl group include a methyl group, an ethyl group, an isopropyl group, a butyl group, an isobutyl group, a hexyl group, an octyl group, and a 2-ethylhexyl group.

[0036] From the viewpoint of enhancing the fluidity of the compound, the epoxy resin preferably contains at least one crystalline epoxy resin. Crystalline epoxy resins have a melting point and do not soften at temperatures below the melting point, thereby exhibiting excellent fluidity.

[0037] Examples of crystalline epoxy resins include hydroquinone type epoxy resins, bisphenol type epoxy resins, thioether type epoxy resins, biphenyl novolac type epoxy resins, and biphenyl type epoxy resins.

[0038] Commercially available crystalline epoxy resins include, for example, Epicron 860, Epicron 1050, Epicron 1055, Epicron 2050, Epicron 3050, Epicron 4050, Epicron 7050, Epicron HM-091, Epicron HM-101, Epicron N-730A, Epicron N-740, Epicron N-770, and Epicron N- -775, Epicron N-865, Epicron HP-4032D, Epicron HP-7200L, Epicron HP-7200, Epicron HP-7200H, Epicron HP-7200HH, Epicron HP-7200HHH, Epicron HP-4700, Epicron HP-4710, Epicron HP-4770, Epicron HP-5000, Epicron HP-6000 and N500P-2 (all trade names of DIC Corporation), NC-3000, NC-3000-L, NC-3000-H, NC-3100, CER-3000-L, NC-2000-L, XD-1000, NC-7000-L, NC-7300-L, EPPN-501H, EPPN-501HY, EPPN-502 H, EOCN-1020, EOCN-102S, EOCN-103S, EOCN-104S, CER-1020, EPPN-201, BREN-S, BREN-10S (all of which are trade names manufactured by Nippon Kayaku Co., Ltd.), YX-4000, YX-4000H, YL4121H, YX-8800 (all of which are trade names manufactured by Mitsubishi Chemical Corporation), and the like.

[0039] The epoxy resin (A) in this embodiment preferably contains an epoxy resin that is solid at room temperature (25°C).

[0040] The content of the epoxy resin that is solid at room temperature (25°C) is preferably 50 mass% or more, more preferably 75 mass% or more, and even more preferably 95 mass% or more, based on the total amount of epoxy resins. When the epoxy resin (A) satisfies the above-mentioned constitution, blocking during storage of the compound can be suppressed.

[0041] The content of the epoxy resin (A) is preferably 0.3% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, and even more preferably 0.8% by mass or more and 10% by mass or less, relative to the total mass of the bonded magnet compound. By keeping the epoxy resin content within this range, the bonded magnet can achieve both good magnetic properties and good mechanical strength.

[0042] The epoxy resin content is preferably 0.5 to 40% by volume of the total volume of the bonded magnet compound, more preferably 0.8 to 30% by volume, and even more preferably 1.0 to 20% by volume. By keeping the epoxy resin content within this range, the bonded magnet can achieve both good magnetic properties and mechanical strength.

[0043] <Curing agent (B) different from curing agent having an imidazole structure> The compound of the present embodiment preferably contains a curing agent (B) different from the curing agent (D) having an imidazole structure.

[0044] Examples of the curing agent (B) different from the curing agent having an imidazole structure include, but are not limited to, aliphatic polyamines, polyaminoamides, polymercaptans, aromatic polyamines, acid anhydrides, phenolic resins, and dicyandiamide (DICY).

[0045] As the curing agent (B) different from the curing agent having an imidazole structure, from the viewpoint of improving the heat resistance of the bonded magnet, it is preferable to use an aromatic polyamine, an acid anhydride, a phenolic resin, or dicyandiamide (DICY), and among these, it is more preferable to use a phenolic resin.

[0046] Examples of aromatic polyamines include diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, diethyltoluenediamine, trimethylenebis(4-aminobenzoate), polytetramethyleneoxide-di-p-aminobenzoate, etc. Commercially available aromatic polyamines may be used, such as KAYAHARD AA (manufactured by Nippon Kayaku Co., Ltd.) and Ethacure 100 (manufactured by Mitsui Chemicals Fine Chemicals Co., Ltd.).

[0047] Examples of acid anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0048] Examples of phenolic resins include aralkyl-type phenolic resins, dicyclopentadiene-type phenolic resins, salicylaldehyde-type phenolic resins, novolac-type phenolic resins, copolymerized phenolic resins of benzaldehyde-type phenols and aralkyl-type phenols, paraxylylene- and / or metaxylylene-modified phenolic resins, melamine-modified phenolic resins, terpene-modified phenolic resins, dicyclopentadiene-type naphthol resins, cyclopentadiene-modified phenolic resins, polycyclic aromatic ring-modified phenolic resins, biphenyl-type phenolic resins, triphenylmethane-type phenolic resins, etc. The phenolic resin may be a copolymer composed of two or more of the above.

[0049] The phenol resin is preferably a novolac type phenol resin from the viewpoint of increasing the heat resistance of the bonded magnet.

[0050] Examples of novolac phenolic resins include resins obtained by condensing or co-condensing phenols and / or naphthols with aldehydes under an acidic catalyst. Examples of phenols constituting novolac phenolic resins include phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol. Examples of naphthols constituting novolac phenolic resins include α-naphthol, β-naphthol, and dihydroxynaphthalene. Examples of aldehydes constituting novolac phenolic resins include formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde.

[0051] The curing agent (B) different from the curing agent having an imidazole structure can be, for example, a compound having two phenolic hydroxyl groups in one molecule. Examples of the compound having two phenolic hydroxyl groups in one molecule include resorcinol, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenol. The curing agent may be used alone or in combination of two or more thereof.

[0052] The ratio of active groups (phenolic OH groups) in the curing agent that react with the epoxy groups in the epoxy resin is preferably 0.5 to 1.5 equivalents, more preferably 0.7 to 1.4 equivalents, and even more preferably 0.8 to 1.3 equivalents, per equivalent of epoxy groups in the epoxy resin. By ensuring that the ratio of active groups in the curing agent satisfies the above range, the mechanical properties and heat resistance of the bonded magnet can be improved.

[0053] In this embodiment, the curing agent (B) different from the curing agent having an imidazole structure preferably contains a curing agent that is solid at room temperature (25°C). The content of the curing agent that is solid at room temperature (25°C) is preferably 50% by mass or more, more preferably 75% by mass or more, and even more preferably 95% by mass or more, based on the total amount of the curing agent. When the curing agent satisfies the above-mentioned configuration, blocking during storage of the compound can be suppressed.

[0054] The content of the curing agent (B) different from the curing agent having an imidazole structure is preferably 0.3% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, and even more preferably 0.8% by mass or more and 10% by mass or less, based on the total mass of the bonded magnet compound. By ensuring that the content of the curing agent (B) different from the curing agent having an imidazole structure satisfies the above range, the magnetic properties and mechanical strength of the bonded magnet can be compatible.

[0055] The content of the curing agent (B) different from the curing agent having an imidazole structure is preferably 0.5% by volume or more and 40% by volume or less, more preferably 0.8% by volume or more and 30% by volume or less, and even more preferably 1.0% by volume or more and 20% by volume or less, relative to the total volume of the bonded magnet compound. By ensuring that the content of the curing agent (B) different from the curing agent having an imidazole structure satisfies the above range, the magnetic properties and mechanical strength of the bonded magnet can be compatible.

[0056] <Metal Element-Containing Particles (C)> The compound of this embodiment contains metal element-containing particles. The metal element-containing particles may contain, for example, at least one selected from the group consisting of a simple metal, an alloy, and a metal compound. The metal element-containing particles may be composed of, for example, at least one selected from the group consisting of a simple metal, an alloy, and a metal compound. The alloy may contain at least one selected from the group consisting of a solid solution, a eutectic, and an intermetallic compound. The alloy may be, for example, stainless steel (such as an Fe—Cr alloy or an Fe—Ni—Cr alloy). The metal compound may be, for example, an oxide such as ferrite. The metal element-containing particles may contain one metal element or multiple metal elements. The metal element contained in the metal element-containing particles may be, for example, a base metal element, a noble metal element, a transition metal element, or a rare earth element. The metal element contained in the metal element-containing particle may be, for example, at least one selected from the group consisting of iron (Fe), copper (Cu), titanium (Ti), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), tin (Sn), chromium (Cr), barium (Ba), strontium (Sr), lead (Pb), silver (Ag), praseodymium (Pr), neodymium (Nd), samarium (Sm), and dysprosium (Dy). The metal element-containing particle may also contain elements other than metal elements. The metal element-containing particle may also contain, for example, oxygen (O), beryllium (Be), phosphorus (P), boron (B), or silicon (Si).

[0057] The metal element-containing particles may be used singly or in combination of two or more. When two or more types of metal element-containing particles are mixed, two or more types of metal element-containing particles having different compositions, particle diameters (particle size distribution), shapes, specific surface areas, properties (isotropy, anisotropy), surface treatments, etc. may be mixed and used.

[0058] The alloy composition of the metal element-containing particles is not limited as long as it does not deteriorate the curing properties of the resin composition.

[0059] The metal element-containing particles are preferably magnetic particles.

[0060] Examples of magnetic particles that can be used include samarium-cobalt (Sm—Co) based alloy particles (rare earth magnetic particles), neodymium-iron-boron (Nd—Fe—B) based alloy particles (rare earth magnetic particles), samarium-iron-nitrogen (Sm—Fe—N) based alloy particles (rare earth magnetic particles), iron-cobalt (Fe—Co) based alloy particles, Al—Ni—Co based alloy particles, and ferrite based magnetic particles.

[0061] The magnetic particles of this embodiment are preferably rare earth magnetic particles. In this embodiment, rare earth magnetic particles refer to magnetic particles containing a rare earth element. Rare earth magnetic particles have superior coercivity and magnetic flux density compared to other magnetic particles, and can increase the magnetic force of, for example, a bonded magnet.

[0062] The shape of the magnetic particles is not particularly limited, but spherical, flat, prismatic, needle-shaped magnetic particles, etc. can be used alone or in combination. The shape of the magnetic particles can be evaluated by the circularity coefficient, which is measured by image processing of images observed under a microscope. The circularity coefficient is a value defined by the following formula, and the higher the value, the more rounded the particles are and the closer they are to a sphere. From the viewpoint of facilitating rotation of the magnetic particles during magnetic field molding and improving orientation, it is preferable to include at least one type of magnetic particle having a circularity coefficient of 0.60 or more. Circularity coefficient = (4πS / L ２ ) where S is the two-dimensional projected area of ​​the particle, and L is the two-dimensional projected perimeter.

[0063] The magnetic particles may have a particle size (particle size distribution) of either coarse magnetic particles (hereinafter simply referred to as "coarse particles") or fine magnetic particles (hereinafter simply referred to as "fine particles"), and these may be used alone or in combination.

[0064] The average particle size (D50) of the coarse particles is preferably 30 μm or more and 300 μm or less, and more preferably 40 μm or more and 250 μm or less. Because the coarse particles have high magnetic properties, the magnetic properties of the bonded magnet can be adjusted according to the amount of coarse particles added.

[0065] The average particle size (D50) of the fine particles is preferably 0.5 μm or more and 30 μm or less, and more preferably 1 μm or more and 20 μm or less. The fine particles can increase the filling amount of magnetic particles, thereby improving the magnetic properties.

[0066] The average particle size and particle size distribution of the magnetic particles are measured using a laser diffraction particle size distribution measuring device (HELOS, manufactured by Nippon Laser Co., Ltd.).

[0067] The specific surface area of ​​the magnetic particles is 0.005 m ２ / g or more 5.0m ２ / g or less is preferable, and 0.01m ２ / g or more 1.5m ２ / g or less is more preferable, and 0.03m ２ / g or more 1.3m ２ / g or less is more preferable, and 0.05m ２ / g or more 1.0m ２ / g or less is particularly preferred.

[0068] By using magnetic particles that satisfy the above-mentioned structure, it is possible to achieve both magnetic properties and mechanical strength of the bonded magnet, and also to increase the fluidity of the compound.

[0069] The specific surface area of ​​the magnetic particles can be controlled by changing the shape or average particle diameter of the magnetic particles. When multiple types of magnetic particles are used in combination, the specific surface area of ​​the magnetic particles after mixing can be adjusted to fall within the above range.

[0070] The specific surface area was measured using a BET specific surface area measuring device. ２The measurement is performed using a mixed gas of He / He = 30 / 70 (volume ratio) as the adsorbed gas. When two or more types of magnetic particles are contained, the specific surface area is calculated as the average value for all magnetic particles based on the specific surface area and content ratio of each magnetic particle.

[0071] The properties of the magnetic particles are not particularly limited, but anisotropic magnetic particles and isotropic magnetic particles can be used alone or in combination. By preparing a compound using anisotropic magnetic particles and then orienting the magnetic particles in the bonded magnet compact by magnetic field molding, the magnetic properties can be improved.

[0072] The magnetic particles are preferably subjected to anti-rust treatment. Examples of anti-rust treatment include phosphate treatment to form a phosphate compound layer, metal alkoxy oligomer treatment to form an organometallic compound layer, coupling treatment to form a coupling agent layer, and gradual oxidation treatment to form an oxide film. The anti-rust treatment may be performed using a single type of treatment or a combination of multiple types of treatments.

[0073] The content of the magnetic particles is preferably 70% by mass or more and 99.5% by mass or less, more preferably 80% by mass or more and 99.0% by mass or less, and even more preferably 90% by mass or more and 98.5% by mass or less, based on the total mass of the bonded magnet compound. By keeping the content of the magnetic particles within this range, the bonded magnet can achieve both good magnetic properties and good mechanical strength.

[0074] <Curing Agent (D) Having Imidazole Structure> The compound of the present embodiment contains a compound represented by formula (1) and / or a compound represented by formula (2) as a curing agent (D) having an imidazole structure.

[0075] The compound of this embodiment, which satisfies the above-mentioned requirements, surprisingly has a long usable life in the manufacturing process, exhibits little change in properties due to heating during bonded magnet molding, and can impart high mechanical strength even when the thermosetting resin is cured under low temperature conditions. These effects cannot be easily predicted from the structure of the curing agent (D) having an imidazole structure.

[0076] Furthermore, the inventors of the present invention have investigated the effects of imidazole compounds having various structures in the process of developing the compound of this embodiment, and have found that the curing agent (D) having an imidazole structure of this embodiment is optimal as a compound that provides the above-mentioned effects. The mechanism of the above-mentioned effects is considered as follows.

[0077] The curing agent (D) having an imidazole structure in this embodiment is a compound having an imidazole structure.Generally, it is known that the nitrogen atom on the imidazole compound has the ability to coordinate with metal, and when the imidazole compound and the metal element-containing particle (magnetic particle) coexist, it is considered that the nitrogen atom of the imidazole compound is adsorbed to the metal element-containing particle (magnetic particle).Therefore, when a compound is prepared using imidazole compounds having various structures, the imidazole compound in the compound may be concentrated near the surface of the metal element-containing particle (magnetic particle), and the dispersibility of the imidazole compound may be reduced.

[0078] On the other hand, the compounds represented by formulas (1) and (2) have a structure in which a hydroxyphenyl group is substituted at the 2-position of the imidazole structure. The nitrogen atom, which is the active site of the imidazole, forms an intramolecular hydrogen bond with the adjacent hydroxyphenyl group. This is thought to suppress the nucleophilicity of the nitrogen atom on the imidazole in low-temperature environments (e.g., below 120°C), allowing it to be uniformly dispersed in the compound. In addition, since the nucleophilicity toward epoxy groups is also suppressed, the pot life in the manufacturing process is excellent and changes in properties during bonded magnet molding can be suppressed.

[0079] Furthermore, it is presumed that when the bonded magnet hardens (for example, at 120°C or higher), the intramolecular hydrogen bonds gradually dissociate as the temperature of the compound rises, and some of the compounds represented by formulas (1) and (2) adsorb to the metal element-containing particles (magnetic particles). As a result, when a cured bonded magnet is produced using the compounds represented by formulas (1) and (2), the compounds represented by formulas (1) and (2) can be dispersed throughout the compound system while selectively increasing their concentration near the surfaces of the metal element-containing particles (magnetic particles). Therefore, the crosslink density near the surfaces of the metal element-containing particles (magnetic particles) can be particularly increased while maintaining the hardened strength of the entire bonded magnet.

[0080] Normally, the mechanical strength of a composite material (resin component, magnetic particles, etc.) tends to be weakest at the interface between the materials. However, by using the compounds represented by formulas (1) and (2), the crosslink density at the interface increases, and it is presumed that high mechanical strength can be imparted even when the thermosetting resin is subjected to a curing reaction under low-temperature conditions.

[0081]

[0082]

[0083] In formulas (1) and (2), R １ and R ２ are each independently any one selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, and a cycloalkyl group having 6 to 20 carbon atoms which may have a substituent. １ and R ２ may be the same or different, and R １ and R ２ may be bonded to form a fused ring that does not have aromaticity.

[0084] X is any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aralkyl group having 7 to 20 carbon atoms which may have a substituent, and a heteroarylalkyl group having 4 to 20 carbon atoms which may have a substituent.

[0085] Y and Z are each independently any one selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and an acyl group having 1 to 20 carbon atoms which may have a substituent. Y and Z may be the same or different, and two or more Ys or two or more Zs may be bonded to form a monocyclic or fused ring. m and n are each independently an integer of 1 to 4.

[0086] R in the above formula (1) １ and R ２ As described above, each independently represents one selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, and a cycloalkyl group having 6 to 20 carbon atoms which may have a substituent, and R １ and R ２ may be bonded to form a fused ring having no aromaticity, R １ and R ２ may be the same or different.

[0087] The alkyl group having 1 to 20 carbon atoms may be linear or branched, and the number of carbon atoms in the alkyl group is preferably 1 to 18, more preferably 1 to 15, and even more preferably 1 to 10. Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an isopropyl group, a butyl group, an isobutyl group, a hexyl group, an octyl group, and a 2-ethylhexyl group.

[0088] The number of carbon atoms in the cycloalkyl group having 6 to 20 carbon atoms is preferably 6 to 18, and more preferably 6 to 15. Examples of the cycloalkyl group having 6 to 20 carbon atoms include a cyclohexyl group, a cycloheptane group, and a cyclooctane group.

[0089] R １ and R２ Specific examples of the non-aromatic fused ring that can be formed by bonding include cyclopentane, cyclohexane, and dicyclopentadiene.

[0090] In addition, the alkyl group, the cycloalkyl group, and R １ and R ２ The non-aromatic fused ring that can be formed by bonding may have a substituent, and examples of the substituent include a halogen atom, a hydroxyl group, an alkoxy group, and a nitro group, and preferred are a hydroxyl group and an alkoxy group.

[0091] X in the formulas (1) and (2) is any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aralkyl group having 7 to 20 carbon atoms which may have a substituent, and a heteroarylalkyl group having 4 to 20 carbon atoms which may have a substituent.

[0092] The alkyl group having 1 to 20 carbon atoms represented by X may be linear or branched, and the number of carbon atoms in the alkyl group is preferably 1 to 18, more preferably 1 to 15. Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an isopropyl group, a butyl group, an isobutyl group, a hexyl group, and an octyl group.

[0093] The alkenyl group having 2 to 20 carbon atoms represented by X may be linear or branched, and the number of carbon atoms in the alkenyl group is preferably 2 to 18, and more preferably 2 to 15. Examples of the alkenyl group having 2 to 20 carbon atoms include a vinyl group, an aryl group, a 1-propenyl group, an isopropenyl group, a 2-butenyl group, a 3-butenyl group, a 2-pentenyl group, and a 2-hexenyl group.

[0094] The aralkyl group having 7 to 20 carbon atoms represented by X may be linear or branched, and the number of carbon atoms in the aralkyl group is preferably 7 to 18, more preferably 7 to 15. Examples of the aralkyl group having 7 to 20 carbon atoms include a benzyl group, a phenethyl group, and a naphthylmethyl group.

[0095] The heteroarylalkyl group having 4 to 20 carbon atoms represented by X may be linear or branched, and the number of carbon atoms in the heteroarylalkyl group is preferably 4 to 18, and more preferably 4 to 15. Examples of the heteroarylalkyl group having 4 to 20 carbon atoms include a triazinylmethyl group, a triazinylethyl group, a 2-pyridylmethyl group, a 2-pyridylethyl group, a 3-pyridylmethyl group, a 3-pyridylethyl group, a 4-pyridylmethyl group, and a 4-pyridylethyl group.

[0096] The alkyl group, alkenyl group, aralkyl group, and heteroarylalkyl group may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, a hydroxyl group, an alkoxy group, an amino group, an ester group, an arylsulfonyl group, an alkylsulfonyl group, and a phenyl group, and preferred are a cyano group, an alkoxy group, an amino group, an ester group, and a phenyl group.

[0097] Y and Z in the formulas (1) and (2) are each independently any one selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and an acyl group having 1 to 20 carbon atoms which may have a substituent; two or more Ys or two or more Zs may be bonded to form a monocycle or a condensed ring; and m and n are each independently an integer of 1 to 4.

[0098] The alkyl group having 1 to 20 carbon atoms represented by Y and Z may be linear or branched, and the number of carbon atoms in the alkyl group is preferably 1 to 18, more preferably 1 to 15. Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a decyl group, and an undecyl group.

[0099] The alkoxy group having 1 to 20 carbon atoms represented by Y and Z may be linear or branched, and preferably has 1 to 18 carbon atoms, more preferably 1 to 15 carbon atoms. Examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a hexyloxy group, and a 2-ethylhexyloxy group.

[0100] The alkenyl group having 2 to 20 carbon atoms represented by Y and Z may be linear or branched, and the number of carbon atoms in the alkenyl group is preferably 2 to 18, more preferably 2 to 15. Examples of the alkenyl group having 2 to 20 carbon atoms include a vinyl group, an aryl group, a 1-propenyl group, an isopropenyl group, a 2-butenyl group, a 3-butenyl group, a 2-pentenyl group, and a 2-hexenyl group.

[0101] The number of carbon atoms in the aryl group having 6 to 20 carbon atoms represented by Y and Z is preferably 6 to 18, more preferably 6 to 15. Examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a naphthyl group, an anthracenyl group, and a biphenyl group.

[0102] Examples of the structure in which two or more Y's or two or more Z's are bonded to form a single ring or a condensed ring include a naphthyl group and an anthracenyl group.

[0103] The number of carbon atoms in the acyl group having 1 to 20 carbon atoms represented by Y and Z is preferably 1 to 18, more preferably 1 to 15. Examples of the acyl group having 1 to 20 carbon atoms include an acetyl group, a benzoyl group, and a pivaloyl group.

[0104] The alkyl group, alkoxy group, alkenyl group, aryl group, aryloxy group, and acyl group may have a substituent. Examples of the substituent include an alkyl group, a halogen atom, a hydroxyl group, a carboxy group, an alkoxy group, a nitro group, an ester group, and a phenyl group, and preferred are an alkyl group, a hydroxyl group, a carboxy group, and an alkoxy group.

[0105] Y may be substituted at any of the ortho, meta, or para positions of the phenyl group which is the substituent at the 2-position of the imidazole; however, when Y has a substituent, it is preferably substituted at a position other than the ortho position, more preferably at least at the meta position, and even more preferably at the meta position with a hydroxyl group or an alkoxy group having 1 to 20 carbon atoms which may have a substituent.

[0106] Among the above, it is more preferable that Y and Z in formulas (1) and (2) are each independently one selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxy group, an alkoxy group having 1 to 20 carbon atoms and no substituent, an alkyl group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxy group as a substituent, an alkoxy group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxy group as a substituent, an aryl group having 6 to 20 carbon atoms and having a hydroxyl group and / or a carboxy group as a substituent, an aryloxy group having 6 to 20 carbon atoms and having a hydroxyl group and / or a carboxy group as a substituent, and an acyl group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxy group as a substituent.

[0107] Furthermore, when Y and Z are each independently a hydroxyl group, a carboxyl group, an alkoxy group having 1 to 20 carbon atoms and no substituent, an alkyl group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, an alkoxy group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, an aryl group having 6 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, an aryloxy group having 6 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, or an acyl group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, the coordination ability to the metal element-containing particles is increased, which tends to improve the mechanical strength of the bonded magnet.

[0108] The compound represented by the formula (1) includes, but is not limited to, the following imidazole compounds.

[0109] For example, 2-(2-hydroxyphenyl)imidazole, 2-(2-hydroxyphenyl)-4(5)-methylimidazole, 4(5)-ethyl-2-(2-hydroxyphenyl)imidazole, 4,5-dimethyl-2-(2-hydroxyphenyl)imidazole, 4-ethyl-(2-hydroxyphenyl)-5-methylimidazole, (2-hydroxyphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-(2-hydroxyphenyl)-5-methylimidazole, 2-(2-hydroxy-3-methylphenyl)imidazole, 2-(2-hydroxy-3-methylphenyl)-4(5)-methylimidazole, 4(5)-ethyl 2-(2-hydroxy-3-methylphenyl)imidazole, 4,5-dimethyl-2-(2-hydroxy-3-methylphenyl)imidazole, 4-ethyl-(2-hydroxy-3-methylphenyl)-5-methylimidazole, (2-hydroxy-3-methylphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-(2-hydroxy-3-methylphenyl)-5-methylimidazole, 2-(2-hydroxy-4-methylphenyl)imidazole, 2-(2-hydroxy-4-methylphenyl)-4(5)-methylimidazole, 4(5)-ethyl-2-(2-hydroxy-4-methylphenyl)imidazole, and the like.

[0110] Also, 4,5-dimethyl-2-(2-hydroxy-4-methylphenyl)imidazole, 4-ethyl-(2-hydroxy-4-methylphenyl)-5-methylimidazole, (2-hydroxy-4-methylphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-(2-hydroxy-4-methylphenyl)-5-methylimidazole, 2-(2-hydroxy-5-methylphenyl)imidazole, 2-(2-hydroxy-5-methylphenyl)-4(5)-methylimidazole, 4(5)-ethyl-2-(2-hydroxy-5-methylphenyl)imidazole, 4,5-di Examples thereof include methyl-2-(2-hydroxy-5-methylphenyl)imidazole, 4-ethyl-(2-hydroxy-5-methylphenyl)-5-methylimidazole, (2-hydroxy-5-methylphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-(2-hydroxy-5-methylphenyl)-5-methylimidazole, 2-(3-t-butyl-2-hydroxyphenyl)imidazole, 2-(3-t-butyl-2-hydroxyphenyl)-4(5)-methylimidazole, and 2-(3-t-butyl-2-hydroxyphenyl)-4(5)-ethylimidazole.

[0111] Further, 2-(3-t-butyl-2-hydroxyphenyl)-4,5-dimethylimidazole, 2-(3-t-butyl-2-hydroxyphenyl)-4-ethyl-5-methylimidazole, 2-(3-t-butyl-2-hydroxyphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-2-(3-t-butyl-2-hydroxyphenyl)-5-methylimidazole, 2-(4-fluoro-2-hydroxyphenyl)imidazole, 2-(4-fluoro-2-hydroxyphenyl)-4(5)-methylimidazole, 2-(4-fluoro-2-hydroxyphenyl)-4(5)-ethylimidazole 2-(4-fluoro-2-hydroxyphenyl)-4,5-dimethylimidazole, 4-ethyl-2-(4-fluoro-2-hydroxyphenyl)-5-methylimidazole, 2-(4-fluoro-2-hydroxyphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-2-(4-fluoro-2-hydroxyphenyl)-5-methylimidazole, 2-(4-chloro-2-hydroxyphenyl)imidazole, 2-(4-chloro-2-hydroxyphenyl)-4(5)-methylimidazole, 2-(4-chloro-2-hydroxyphenyl)-4(5)-ethylimidazole, and the like.

[0112] Further, 2-(4-chloro-2-hydroxyphenyl)-4,5-dimethylimidazole, 2-(4-chloro-2-hydroxyphenyl)-4-ethyl-5-methylimidazole, 2-(4-chloro-2-hydroxyphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-2-(4-chloro-2-hydroxyphenyl)-5-methylimidazole, 2-(4-bromo-2-hydroxyphenyl)imidazole, and 2-(4-bromo-2-hydroxyphenyl)-4(5)-methylimidazole , 2-(4-bromo-2-hydroxyphenyl)-4(5)-ethylimidazole, 2-(4-bromo-2-hydroxyphenyl)-4,5-dimethylimidazole, 2-(4-bromo-2-hydroxyphenyl)-4-ethyl-5-methylimidazole, 2-(4-bromo-2-hydroxyphenyl)-4-isopropyl-5-methylimidazole, 2-(4-bromo-2-hydroxyphenyl)-4-butyl-5-methylimidazole, 2-(2,3-dihydroxyphenyl)imidazole, and the like.

[0113] Furthermore, 2-(2,3-dihydroxyphenyl)-4(5)-methylimidazole, 2-(2,3-dihydroxyphenyl)-4(5)-ethylimidazole, 2-(2,3-dihydroxyphenyl)-4,5-dimethylimidazole, 2-(2,3-dihydroxyphenyl)-4(5)-phenylimidazole, 2-(2,3-dihydroxyphenyl)-4,5-diphenylimidazole, 2-(2,5-dihydroxyphenyl)imidazole, 2-(2,5-dihydroxyphenyl)-4(5)-methylimidazole, 2-(2,5-dihydroxyphenyl)-4(5)-ethylimidazole, 2-(2,5-dihydroxyphenyl)-4,5-dimethylimidazole, 2-(2,5-dihydroxyphenyl)-4(5)-phenyl ...

[0033] Examples of the 4-hydroxyphenylimidazole include 2-(2-hydroxy-4-methoxyphenyl)imidazole, 2-(2-hydroxy-4-methoxyphenyl)-4(5)-methylimidazole, 4(5)-ethyl-2-(2-hydroxy-4-methoxyphenyl)imidazole, 4,5-dimethyl-2-(2-hydroxy-4-methoxyphenyl)imidazole, 2-(2-hydroxy-4-methoxyphenyl)-4(5)-phenylimidazole, 4,5-diphenyl-2-(2-hydroxy-4-methoxyphenyl)imidazole, 2-(2-hydroxy-3-methoxyphenyl)imidazole, 2-(2-hydroxy-3-methoxyphenyl)-4(5)-methylimidazole, and 4(5)-ethyl-2-(2-hydroxy-3-methoxyphenyl)imidazole.

[0114] Also, 4,5-dimethyl-2-(2-hydroxy-3-methoxyphenyl)imidazole, 2-(2-hydroxy-3-methoxyphenyl)-4(5)-phenylimidazole, 4,5-diphenyl-2-(2-hydroxy-3-methoxyphenyl)imidazole, 2-(2-hydroxy-5-methoxyphenyl)imidazole, 2-(2-hydroxy-5-methoxyphenyl)-4(5)-methylimidazole, 4(5)-ethyl-2-(2-hydroxy-5-methoxyphenyl)imidazole, 4,5-dimethyl-2-(2-hydroxy-5-methoxyphenyl)imidazole, 2-(2-hydroxy-5-methoxyphenyl)-4(5)-phenylimidazole, 4,5-diphenyl-2-(2-hydroxy-5-methoxyphenyl)imidazole, 2-(2-hydroxy-6-methoxyphenyl)imidazole, 2-(2-hydroxy- 2-(2-hydroxy-6-methoxyphenyl)-4(5)-methylimidazole, 4(5)-ethyl-2-(2-hydroxy-6-methoxyphenyl)imidazole, 4,5-dimethyl-2-(2-hydroxy-6-methoxyphenyl)imidazole, 2-(2-hydroxy-6-methoxyphenyl)-4(5)-phenylimidazole, 4,5-diphenyl-2-(2-hydroxy-6-methoxyphenyl)imidazole, 2-(3-ethoxy-2-hydroxyphenyl)imidazole, 2-(3-ethoxy-2-hydroxyphenyl)-4(5)-methylimidazole, 2-(3-ethoxy-2-hydroxyphenyl)-4(5)-ethylimidazole, 4,5-dimethyl-2-(3-ethoxy-2-hydroxyphenyl)imidazole, 2-(3-ethoxy-2-hydroxyphenyl)-4(5)-phenylimidazole and the like.

[0115] Further, 4,5-diphenyl-2-(3-ethoxy-2-hydroxyphenyl)imidazole, 2-(5-ethoxy-2-hydroxyphenyl)imidazole, 2-(5-ethoxy-2-hydroxyphenyl)imidazole, 2-(5-ethoxy-2-hydroxyphenyl)-4(5)-methylimidazole, 2-(5-ethoxy-2-hydroxyphenyl)-4(5)-ethylimidazole, 4,5-dimethyl-2-(5-ethoxy-2-hydroxyphenyl)imidazole, 2-(5-ethoxy-2-hydroxyphenyl)-4(5)-phenylimidazole, 4,5-diphenyl-2-(5-ethoxy-2-hydroxyphenyl)imidazole, 2-(4-allyl-2-hydroxyphenyl)imidazole 2-(4-allyl-2-hydroxy-3-methoxyphenyl)imidazole, 2-(4-allyl-2-hydroxy-3-methoxyphenyl)-4(5)-methylimidazole, 2-(4-allyl-2-hydroxy-3-methoxyphenyl)-4(5)-ethylimidazole, 2-(4-allyl-2-hydroxy-3-methoxyphenyl)-4,5-dimethylimidazole, 2-(4-allyl-2-hydroxy-3-methoxyphenyl)-4(5)-phenylimidazole, 2-(4-allyl-2-hydroxy-3-methoxyphenyl)-4,5-diphenylimidazole, 2-(4,6-dimethoxy-2-hydroxyphenyl)imidazole, and the like.

[0116] Further, 2-(4,6-dimethoxy-2-hydroxyphenyl)-4(5)-methylimidazole, 2-(4,6-dimethoxy-2-hydroxyphenyl)-4(5)-ethylimidazole, 2-(4,6-dimethoxy-2-hydroxyphenyl)-4,5-dimethylimidazole, 2-(4,6-dimethoxy-2-hydroxyphenyl)-4(5)-phenylimidazole, 2-(4,6-dimethoxy-2-hydroxyphenyl)-4,5-diphenylimidazole, 2-(2-fluoro-5-hydroxyphenyl)imidazole, 2-(2-fluoro-5-hydroxyphenyl)-4(5)-methylimidazole, imidazole, 2-(2-fluoro-5-hydroxyphenyl)-4(5)-ethylimidazole, 2-(2-fluoro-5-hydroxyphenyl)-4,5-dimethylimidazole, 2-(2-fluoro-5-hydroxyphenyl)-4(5)-phenylimidazole, 2-(2-fluoro-5-hydroxyphenyl)-4,5-diphenylimidazole, 2-(5-fluoro-2-hydroxyphenyl)imidazole, 2-(5-fluoro-2-hydroxyphenyl)-4(5)-methylimidazole, 2-(5-fluoro-2-hydroxyphenyl)-4(5)-ethylimidazole, and the like.

[0117] Furthermore, 2-(5-fluoro-2-hydroxyphenyl)-4,5-dimethylimidazole, 2-(5-fluoro-2-hydroxyphenyl)-4(5)-phenylimidazole, 2-(5-fluoro-2-hydroxyphenyl)-4,5-diphenylimidazole, 2-(5-chloro-2-hydroxyphenyl)imidazole, 2-(5-chloro-2-hydroxyphenyl)-4(5)-methylimidazole, 2-(5-chloro-2-hydroxyphenyl)-4(5)-ethylimidazole, 2-(5-chloro-2-hydroxyphenyl)-4,5-dimethylimidazole, 2-(5-chloro-2-hydroxyphenyl)-4(5)-phenylimidazole imidazole, 2-(5-chloro-2-hydroxyphenyl)-4,5-diphenylimidazole, 2-(5-bromo-2-hydroxyphenyl)imidazole, 2-(5-bromo-2-hydroxyphenyl)-4(5)-methylimidazole, 2-(5-bromo-2-hydroxyphenyl)-4(5)-ethylimidazole, 2-(5-bromo-2-hydroxyphenyl)-4,5-dimethylimidazole, 2-(5-bromo-2-hydroxyphenyl)-4(5)-phenylimidazole, 2-(5-bromo-2-hydroxyphenyl)-4,5-diphenylimidazole, 2-(6-fluoro-2-hydroxy-3-methoxyphenyl)imidazole, and the like.

[0118] Also, 2-(6-fluoro-2-hydroxy-3-methoxyphenyl)-4(5)-methylimidazole, 2-(6-fluoro-2-hydroxy-3-methoxyphenyl)-4(5)-ethylimidazole, 2-(6-fluoro-2-hydroxy-3-methoxyphenyl)-4,5-dimethylimidazole, 2-(6-fluoro-2-hydroxy-3-methoxyphenyl)-4(5)-phenylimidazole, 2-(6-fluoro-2-hydroxy-3-methoxyphenyl)-4,5-diphenylimidazole, 2-(1-hydroxynaphthalen-2-yl)imidazole, 2-(1-hydroxynaphthalen-2-yl)-4(5)-methylimidazole, 2-(1-hydroxynaphthalen-2-yl)-4(5)-ethylimidazole, 4 , 5-dimethyl-2-(1-hydroxynaphthalen-2-yl)imidazole, 2-(1-hydroxynaphthalen-2-yl)-4(5)-phenylimidazole, 4,5-diphenyl-2-(1-hydroxynaphthalen-2-yl)imidazole, 2-(2-hydroxynaphthalen-1-yl)imidazole, 2-(2-hydroxynaphthalen-1-yl)-4(5)-methylimidazole, 2-(2-hydroxynaphthalen-1-yl)-4(5)-ethylimidazole, 4,5-dimethyl-2-(2-hydroxynaphthalen-1-yl)imidazole, 2-(2-hydroxynaphthalen-1-yl)-4(5)-phenylimidazole, 4,5-diphenyl-2-(2-hydroxynaphthalen-1-yl)imidazole and the like.

[0119] Preferred compounds represented by formula (1) are 2-(2-hydroxyphenyl)imidazole, 2-(2-hydroxyphenyl)-4(5)-methylimidazole, 4-ethyl-(2-hydroxyphenyl)-5-methylimidazole, (2-hydroxyphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-(2-hydroxyphenyl)-5-methylimidazole, and 2-(2-hydroxy-3(5)-methoxyphenyl)imidazole.

[0120] The compound represented by the formula (2) includes, but is not limited to, the following imidazole compounds.

[0121] For example, 2-(2-hydroxyphenyl)benzimidazole, 2-(2-hydroxy-3-methylphenyl)benzimidazole, 2-(2-hydroxy-4-methylphenyl)benzimidazole, 2-(2-hydroxy-5-methylphenyl)benzimidazole, 2-(3-t-butyl-2-hydroxyphenyl)benzimidazole, 2-(4-fluoro-2-hydroxyphenyl)benzimidazole, 2-(4-chloro-2-hydroxyphenyl)benzimidazole, 2-(4-bromo-2-hydroxyphenyl)benzimidazole, 2-(2,3-dihydroxyphenyl)benzimidazole, 2-(2,5-dihydroxyphenyl)benzimidazole, 2-(2-hydroxy-4-methoxyphenyl)benzimidazole, 2-(2-hydroxy-3-methoxyphenyl)benzimidazole, 2-(2-hydroxy-5-methoxyphenyl)benzimidazole, 2 -(2-hydroxy-6-methoxyphenyl)benzimidazole, 2-(3-ethoxy-2-hydroxyphenyl)benzimidazole, 2-(5-ethoxy-2-hydroxyphenyl)benzimidazole, 2-(4-allyl-2-hydroxy-3-methoxyphenyl)benzimidazole, 2-(4,6-dimethoxy-2-hydroxyphenyl)benzimidazole, 2-(5-fluoro-2-hydroxyphenyl)benzimidazole, 2-(5-chloro-2-hydroxyphenyl)benzimidazole, 2-(5-bromo-2-hydroxyphenyl)benzimidazole, 2-(6-fluoro-2-hydroxy-3-methoxyphenyl)benzimidazole, 2-(1-hydroxynaphthalen-2-yl)benzimidazole, 2-(2-hydroxynaphthalen-1-yl)benzimidazole, 2-(2-hydroxyphenyl)benzimidazole-6-carboxylic acid and the like.

[0122] Among these, from the viewpoint of obtaining a uniform compound by being excellent in solubility in the epoxy resin (A) and solvents, and also achieving high heat resistance, the compound represented by formula (1) is preferably １ and R ２are preferably all hydrogen atoms or have different substituents. For example, 2-(2-hydroxyphenyl)imidazole, 2-(2-hydroxyphenyl)-4(5)-methylimidazole, 4-ethyl-(2-hydroxyphenyl)-5-methylimidazole, (2-hydroxyphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-(2-hydroxyphenyl)-5-methylimidazole, and 2-(2-hydroxy-3(5)-methoxyphenyl)imidazole are more preferred, and 2-(2-hydroxyphenyl)imidazole is even more preferred.

[0123] Furthermore, from the viewpoint of obtaining similar effects, the compound represented by formula (2) is preferably 2-(2-hydroxyphenyl)benzimidazole, 2-(2-hydroxy-3(5)-methoxyphenyl)benzimidazole, 2-(1-hydroxynaphthalen-2-yl)benzimidazole, 2-(2-hydroxynaphthalen-1-yl)benzimidazole, and 2-(2-hydroxyphenyl)benzimidazole-6-carboxylic acid, and more preferably 2-(2-hydroxyphenyl)benzimidazole and 2-(2-hydroxy-3(5)-methoxyphenyl)benzimidazole. In the compound of this embodiment, the content of the curing agent (D) having an imidazole structure is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, per 100 parts by mass of the epoxy resin (A). When the content of the curing agent satisfies the above range, it is easy to control the mechanical strength during low-temperature curing.

[0124] Furthermore, the content of the curing agent (D) having an imidazole structure is preferably 15.0 parts by mass or less, more preferably 12.0 parts by mass or less, and even more preferably 10.0 parts by mass or less, relative to 100 parts by mass of the epoxy resin (A). When the content of the curing agent satisfies the above range, it is easy to control the storage stability of the compound.

[0125] From the viewpoint of mechanical strength, the content of the curing agent (D) having an imidazole structure (the content (Z) of the curing agent described below) is preferably less than 5.0 mass%, more preferably less than 3.0 mass%, and even more preferably less than 1.0 mass%, of the total mass of the compound of this embodiment. Furthermore, from the viewpoint of the heat resistance of the bonded magnet, it is preferably more than 0.01 mass%, more preferably more than 0.03 mass%, and even more preferably more than 0.05 mass%, of the total mass of the compound of this embodiment.

[0126] <Ratio of specific surface area of ​​magnetic particles to content of curing agent (D) having an imidazole structure> The bonded magnet compound of this embodiment has the following ratios: the content (mass %) of magnetic particles (C) relative to the total mass of the bonded magnet compound is (X), the specific surface area (m ２ / g) is (Y), the content (mass %) of the curing agent (D) having an imidazole structure relative to the total mass of the bonded magnet compound is (Z), it is preferable that (X), (Y) and (Z) satisfy the following formula (γ).

[0127] 0.000010≦(Z) / (X)×(Y)≦0.30...(γ)

[0128] By satisfying the above-mentioned requirements, the bond strength near the interface between the magnetic particles and the resin composition is improved, further increasing the mechanical strength of the bonded magnet. Furthermore, changes in properties due to heating during bonded magnet molding can be further suppressed.

[0129] As described above, the curing agent (D) having an imidazole structure in this embodiment interacts with the magnetic particle surface during the temperature rise process, and the concentration of the curing agent (D) having an imidazole structure near the magnetic particle surface can be selectively increased. Therefore, it is preferable to adjust the content of the curing agent (D) relative to the total mass of the compound according to the surface area of ​​the magnetic particles. As a result, the interaction between the curing agent (D) having an imidazole structure and the magnetic particle surface can be effectively expressed.

[0130] The value of (X) x (Y) in formula (γ) is an index representing the specific surface area of ​​the magnetic particles in the compound, and the larger the value, the larger the surface area of ​​the magnetic particles in the compound.

[0131] Furthermore, the value of (Z) / (X)×(Y) in formula (γ) is an index representing the ratio of the specific surface area of ​​the magnetic particles to the content of the curing agent (D) having an imidazole structure, and by controlling (Z) / (X)×(Y) within a specific range, it is possible to particularly increase the crosslink density near the surfaces of the metal element-containing particles (magnetic particles) while maintaining the cured strength of the entire bonded magnet, which results in improved mechanical strength and moist heat resistance of the bonded magnet.

[0132] In the present embodiment, from the viewpoint of mechanical strength and moist heat resistance, the value of (Z) / (X)×(Y) in formula (γ) is more preferably 0.000050≦(Z) / (X)×(Y)≦0.10, even more preferably 0.00010≦(Z) / (X)×(Y)≦0.050, even more preferably 0.00020≦(Z) / (X)×(Y)≦0.030, and even more preferably 0.00030≦(Z) / (X)×(Y)≦0.050.

[0133] The value of (Z) / (X)×(Y) can be controlled by arbitrarily changing the values ​​of (X), (Y) and (Z).

[0134] <Compound (E) Represented by Formula (3)> The compound of the present embodiment preferably contains a compound (E) represented by formula (3).

[0135]

[0136] In formula (1), R １ ~R ８ R is one selected from the group consisting of hydrogen, an alkyl group (preferably an alkyl group having 1 to 50 carbon atoms), an aromatic group, a substituent containing a hetero atom, and a substituent containing a halogen atom. １ ~R ８ may be the same or different. ４ ~R ８ At least two selected from the above may form a ring to form a condensed ring with the adjacent benzene ring.

[0137] By using a compound that satisfies the above requirements, the adhesion between the metal element-containing particles and the resin composition is improved, further increasing the mechanical strength of the bonded magnet and also improving the moist heat resistance of the bonded magnet.

[0138] The compound represented by the above formula (3) is not particularly limited, but examples thereof include 3-phenoxy-1,2-propanediol, 3-phenoxy-1,3-propanediol, mephenesin (3-(2-methylphenoxy)-1,2-propanediol), guaifenesin (3-(2-methoxyphenoxy)propane-1,2-diol), a compound having a 1,2-propanediol structure formed by ring-opening of the terminal epoxy group of a biphenyl-type epoxy resin, and 1,2-propanediol formed by ring-opening of the terminal epoxy group of a stilbene-type epoxy resin. compounds having a 1,2-propanediyl structure formed by ring-opening of the terminal epoxy group of a diphenylmethane type epoxy resin; compounds having a 1,2-propanediyl structure formed by ring-opening of the terminal epoxy group of a sulfur atom-containing epoxy resin; compounds having a 1,2-propanediyl structure formed by ring-opening of the terminal epoxy group of a phenol novolac type epoxy resin; compounds having a 1,2-propanediyl structure formed by ring-opening of the terminal epoxy group of a novolac type epoxy resin such as a cresol novolac type epoxy resin or a naphthol novolac type epoxy resin compounds having a 1,2-propanediyl structure formed by ring-opening of terminal epoxy groups of dicyclopentadiene-type epoxy resins; compounds having a 1,2-propanediyl structure formed by ring-opening of terminal epoxy groups of salicylaldehyde-type epoxy resins such as salicylaldehyde novolac-type epoxy resins; compounds having a 1,2-propanediyl structure formed by ring-opening of terminal epoxy groups of copolymerized epoxy resins of naphthols and phenols; a compound having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of an epoxidized product of a bisphenol-type epoxy resin; a compound having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a glycidyl ether-type epoxy resin of an alcohol; a compound having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a glycidyl ether-type epoxy resin of a paraxylylene and / or metaxylylene-modified phenol resin;Compounds having a 2-propanediyl structure, compounds having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a glycidyl ether type epoxy resin of a terpene-modified phenolic resin, compounds having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a cyclopentadiene type epoxy resin, compounds having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a glycidyl ether type epoxy resin of a polycyclic aromatic ring-modified phenolic resin, compounds having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a glycidyl ether type epoxy resin of a naphthalene ring-containing phenolic resin, compounds having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a glycidyl ester type epoxy resin compounds having a 1,2-propanediyl structure formed by ring-opening of the terminal epoxy group of a glycidyl- or methylglycidyl-type epoxy resin; compounds having a 1,2-propanediyl structure formed by ring-opening of the terminal epoxy group of an alicyclic epoxy resin; compounds having a 1,2-propanediyl structure formed by ring-opening of the terminal epoxy group of a halogenated phenol novolac-type epoxy resin; compounds having a 1,2-propanediyl structure formed by ring-opening of the terminal epoxy group of a hydroquinone-type epoxy resin; and compounds having a 1,2-propanediyl structure formed by ring-opening of the terminal epoxy group of a trimethylolpropane-type epoxy resin and a linear aliphatic epoxy resin obtained by oxidizing an olefin bond with a peracid such as peracetic acid.

[0139] Among these, from the viewpoints of good compatibility with the epoxy resin (A) and the ability to obtain a uniform resin composition, it is preferable to include at least one selected from the group consisting of a compound having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a biphenyl-type epoxy resin, a compound having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of an orthocresol novolac-type epoxy resin, a compound having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a phenol novolac-type epoxy resin, a compound having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a salicylaldehyde novolac-type epoxy resin, and a compound having a 1,2-propanediyl structure formed by ring-opening of a terminal epoxy group of a naphthol novolac-type epoxy resin. These may be used alone or in combination of two or more.

[0140] The content of the compound represented by formula (3) is preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, and even more preferably 0.001% by mass or more, relative to the total mass of the epoxy resin (A). Furthermore, the content of formula (3) is preferably less than 20% by mass, more preferably less than 15% by mass, even more preferably less than 10% by mass, particularly preferably less than 8% by mass, even more preferably less than 7% by mass, even more preferably less than 6% by mass, even more preferably less than 5% by mass, even more preferably less than 3% by mass, and even more preferably less than 2% by mass. By including 0.00001% by mass or more of the compound represented by formula (3) in the compound of this embodiment, the mechanical strength and moist heat resistance of the bonded magnet can be further improved.

[0141] <Ketone Compound (F)> The compound of this embodiment preferably contains a ketone compound (F). When the compound satisfies the above-mentioned configuration, the adhesion between the metal element-containing particles and the resin composition is improved, and the mechanical strength and moist heat resistance of the bonded magnet can be further improved.

[0142] From the viewpoint of the Tg of the bonded magnet, the content of the ketone compound (F) is preferably less than 5.0 mass%, more preferably less than 1.0 mass%, and even more preferably less than 0.5 mass%, relative to the total mass of the compound. Also, from the viewpoint of the wet heat resistance of the bonded magnet, the content of the ketone compound (F) is preferably more than 0.0001 mass%, more preferably more than 0.0005 mass%, and even more preferably more than 0.001 mass%, relative to the total mass of the compound.

[0143] Examples of the ketone compound include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, cyclohexanone, acetophenone, and propylene glycol monomethyl ether acetate.

[0144] <Lubricant> The compound of this embodiment may contain a lubricant. By including a lubricant in the compound, the flowability and moldability of the compound are improved, and the releasability of the compound is improved. As a result, the accuracy of the shape and dimensions of the bonded magnet is improved, and structural defects of the bonded magnet are more likely to be suppressed.

[0145] The lubricant may be, for example, at least one selected from the group consisting of saturated fatty acids, saturated fatty acid salts, and saturated fatty acid esters. The wax may be, for example, lauric acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, heneicosylic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, calcium laurate, calcium myristate, calcium pentadecylate, calcium palmitate, calcium margaric acid, calcium stearate, calcium arachidic acid, calcium heneicosylate, calcium behenate, calcium lignocerate, calcium cerotic acid, calcium montanic acid, calcium melissic acid, barium laurate, barium myristate, pentadecyl The compound may be at least one selected from the group consisting of barium ester, barium palmitate, barium margarate, barium stearate, barium arachidate, barium heneicosylate, barium behenate, barium lignocerate, barium cerotate, barium montanate, barium melissate, laurate, myristate, pentadecylate, palmitate, margarate, stearate, arachidate, heneicosylate, behenate, lignocerate, cerotate, montanate, and melissate. The compound may contain waxes other than those mentioned above.For example, the wax may be at least one selected from the group consisting of magnesium salts of the saturated fatty acids, aluminum salts of the saturated fatty acids, 12-oxystearic acid, calcium ricinoleate, stearic acid amide, oleic acid amide, erucic acid amide, behenic acid amide, palmitic acid amide, lauric acid amide, hydroxystearic acid amide, methylene bisstearic acid amide, ethylene bisstearic acid amide, ethylene bislauric acid amide, distearyl adipamide, ethylene bisoleic acid amide, dioleyl adipamide, N-stearyl stearic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide, methylol behenic acid amide, ethylene glycol, stearyl alcohol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, silicone oil, silicone grease, fluorine-based oil, fluorine-based grease, fluorine-containing resin powder, paraffin wax, polyethylene wax, amide wax, polypropylene wax, ester wax, carnauba wax, and microwax. The compound may contain one of the lubricants listed above. The compound may contain multiple of the lubricants listed above.

[0146] Instead of or in addition to blending the lubricant into the compound, a dispersion of the internal lubricant may be applied to the inner wall surface of the die (the wall surface that comes into contact with the punch).

[0147] <Coupling Agent> The compound of this embodiment may contain a coupling agent. By including a coupling agent, it is possible to further increase the adhesion between the resin composition and the surfaces of the metal element-containing particles, and to further increase the strength of the bonded magnet.

[0148] Examples of the coupling agent include coupling agents of silane-based compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane; coupling agents of titanium-based compounds; coupling agents of aluminum chelates; and coupling agents of aluminum / zirconium-based compounds.

[0149] <Flow Aid> The compound of this embodiment may contain an inorganic filler as a flow aid. The inorganic filler may be composed of one type of particle, or may be a combination of two or more types of particle.

[0150] The average particle size (D50) of the inorganic filler is preferably 1 μm or less, more preferably 500 nm or less, and even more preferably 100 nm or less, which can increase the space filling rate of the bonded magnet.

[0151] Examples of inorganic fillers include inorganic fine particles such as silica, alumina, calcium carbonate, kaolin clay, titanium oxide, barium sulfate, zinc oxide, aluminum hydroxide, magnesium hydroxide, talc, and mica.

[0152] <Flame Retardant> The compound of this embodiment may contain a flame retardant. By containing a flame retardant, the fire resistance of the compound can be improved. From the viewpoints of environmental safety, recyclability, moldability, and low cost, the flame retardant is preferably at least one selected from the group consisting of bromine-based flame retardants, phosphorus-based flame retardants, hydrated metal compound-based flame retardants, silicone-based flame retardants, nitrogen-containing compounds, hindered amine compounds, organometallic compounds, and aromatic engineering plastics.

[0153] <Organic Solvent (G)> In the compound manufacturing process, a varnish is prepared by dissolving the resin composition in an organic solvent (G), and the surface of each metal element-containing particle constituting the metal element-containing particle is coated with the varnish to obtain a uniform compound. The organic solvent (G) is not limited as long as it is a solvent capable of dissolving the resin composition. The organic solvent (G) may be, for example, at least one solvent selected from the group consisting of acetone, methyl ethyl ketone, methyl isobutyl ketone, benzene, toluene, and xylene. In consideration of workability, the organic solvent (G) is preferably liquid at room temperature, and the boiling point of the organic solvent (G) is preferably 60°C or higher and 150°C or lower. Examples of such solvents include acetone and methyl ethyl ketone.

[0154] <Varnish> The varnish of this embodiment is a varnish containing an epoxy resin (A), a curing agent (D) having an imidazole structure, a curing agent (B) different from the curing agent having an imidazole structure, and an organic solvent (G). The varnish of this embodiment may be used for bonded magnets and can be used in the process of producing a compound described below.

[0155] <Method for Producing Compound> The method for producing the compound of the present embodiment is not particularly limited, and examples thereof include a method of mixing the resin composition at a temperature equal to or higher than the melting point (hereinafter simply referred to as "melt mixing") and a method of dissolving the resin composition in a solvent and mixing the same (hereinafter simply referred to as "dissolution mixing").

[0156] Melt mixing may be carried out by the following method. A mixed powder of the compound raw materials (epoxy resin, metal element-containing particles, curing agent (D) having an imidazole structure, curing agent (B) different from the curing agent having an imidazole structure, and other additives) is obtained by thoroughly mixing them in a mixer. The obtained mixed powder of the compound raw materials is heated and mixed at a temperature equal to or higher than the softening temperature of the resin composition, and solids are crushed as appropriate to obtain the compound.

[0157] The temperature for heat mixing varies depending on the type and amount of the resin composition, but is preferably from 40° C. to 140° C., and more preferably from 60° C. to 120° C. Heat mixing within the above temperature range can enhance the dispersibility of the materials in the compound while suppressing the curing reaction of the resin composition.

[0158] The mixing device is not particularly limited, but for example, a heat kneader can be used. In this case, the dispersibility of the materials can be controlled by changing the amount of compound raw materials added.

[0159] Dissolution and mixing may be carried out by the following method. A solution of the resin composition is obtained by dissolving the raw materials of the resin composition, such as an epoxy resin, a curing agent (D) having an imidazole structure, and a curing agent (B) different from the curing agent having an imidazole structure, in an organic solvent (G). Metal element-containing particles are added to the resin composition solution, and the magnetic particles are dispersed in the resin composition solution. After that, the organic solvent (G) is removed from the solution containing the metal element-containing particles and the resin composition by distillation under reduced pressure and drying. As a result, the surfaces of the metal element-containing particles are coated with the resin composition, and a compound consisting of the metal element-containing particles and the resin composition is obtained.

[0160] In the step of removing the organic solvent (G) from the solution containing the metal element-containing particles and the resin composition, it is preferable to use an evaporator to perform vacuum distillation of the organic solvent (G) at room temperature while stirring the solution. The solid obtained by vacuum distillation is further dried using a vacuum dryer or the like, and then the solid is appropriately pulverized to obtain a compound. Instead of vacuum distillation, atmospheric distillation may be performed while stirring the solution using a kneader or the like. As a method for drying the solid obtained by distillation, the solid may be dried by heating the solid at, for example, 80°C or less, preferably 60°C or less, more preferably 40°C or less.

[0161] <Manufacturing Method of Bonded Magnets> A molded body is obtained by compression molding the compound filled into a mold. The higher the molding pressure, the higher the density of the bonded magnet, but the more likely the magnetic particles are to crack. The molding pressure can be set as desired to suit the characteristics of the compound and the bonded magnet.

[0162] By heat treating the molded body, the resin composition in the molded body hardens, and the magnetic particles in the molded body are bound to each other by the cured resin composition, resulting in a bonded magnet. The heat treatment temperature for the molded body is preferably set to a temperature at which the resin composition is sufficiently hardened. Furthermore, from the viewpoint of suppressing oxidation of the magnetic particle surface, low-temperature hardening and short-time hardening are preferred. The hardening temperature is, for example, preferably 200°C or less, more preferably 180°C or less, and even more preferably 150°C or less. The hardening time is, for example, preferably 120 minutes or less, more preferably 60 minutes or less, and even more preferably 30 minutes or less.

[0163] When orienting the magnetic particles, a magnetic field may be applied before and during molding compression, and during heat treatment of the molded body. When applying a magnetic field during heat treatment of the molded body, for example, the molded body is heated to 100°C to soften the resin composition, and then a magnetic field is applied, thereby further increasing the orientation rate of the magnetic particles. After magnetic field orientation, the compression pressure can be increased until the molded body reaches a predetermined density.

[0164] Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present invention is not limited to the following examples and comparative examples in any way.

[0165] In the following, "parts" and "%" are by mass unless otherwise specified.

[0166] [Bonded Magnet Compound] (Epoxy Resins (A-1) to (A-5)) Table 1 shows the epoxy resins (A-1) to (A-5) used in each of the Examples and Comparative Examples.

[0167]

[0168] (Curing Agents (B-1) to (B-2)) Table 2 shows the curing agents (B-1) to (B-2) used in each of the Examples and Comparative Examples.

[0169]

[0170] (Metal Element-Containing Particles (C-1) to (C-2)) Table 3 shows the metal element-containing particles (C-1) to (C-2) used in each of the examples and comparative examples.

[0171]

[0172] (Filler Particles (R-1) to (R-2)) Table 4 shows the filler particles (R-1) to (R-2) used in each comparative example.

[0173]

[0174] (Curing Agents (D-1) to (D-4)) Table 5 shows the curing agents (D-1) to (D-4) used in each of the Examples and Comparative Examples.

[0175]

[0176] (Curing Agents (D'-1) to (D'-12)) Table 6 shows the curing agents (D'-1) to (D'-12) used in each comparative example.

[0177]

[0178] (Compounds (E-1) to (E-2) Represented by Formula (3)) Compounds (E-1) to (E-2) represented by formula (3) used in each example and comparative example are shown in Table 7.

[0179]

[0180] [Preparation of Bonded Magnet Compound] (Example 1) 2.0 g of epoxy resin (A-1), 1.49 g of curing agent (B-1), 0.06 g of curing agent (D-1), and 20.0 g of methyl ethyl ketone were mixed in a 300 mL eggplant flask and stirred for an additional 30 minutes to prepare a solution of the resin composition (resin solution).

[0181] 13.6 g of metal element-containing particles (C-1) and 54.4 g of metal element-containing particles (C-2) were added to the eggplant flask containing the resin solution and stirred at 25°C for 30 minutes. Subsequently, the methyl ethyl ketone in the flask was distilled off by reducing the pressure in the evaporator to 0.1 MPa or less. During the distillation of the methyl ethyl ketone, in order to uniformly remove the methyl ethyl ketone, the following operations were repeated several times: reducing the pressure in the flask, restoring the pressure in the flask to normal pressure, and loosening the aggregated contents in the flask. After the methyl ethyl ketone was distilled off, the mixture of the resin composition and magnetic particles was recovered from the flask and spread on a flat plate. The mixture on the flat plate was vacuum-dried at room temperature in a vacuum dryer, the vacuum dryer was returned to normal pressure, and the aggregates were loosened, in this order. Drying was terminated when the methyl ethyl ketone content in the mixture reached 0.05% by mass, and compound (CPD-1) was obtained.

[0182] The above resin solution and the resulting compound were evaluated as follows.

[0183] (Examples 2 to 7, Examples 9 to 14, Examples 16 to 18, Comparative Examples 1 to 14) Bonded magnet compounds (CPD-2) to (CPD-7), (CPD-9) to (CPD-14), (CPD-16) to (CPD-17), and (CPD-18) to (CPD-32) were obtained in the same manner as in Example 1, except that the formulation was changed to the formulation shown in Table 8. Evaluations were carried out in the same manner as in Example 1.

[0184] Example 8 A compound (CPD-8) was obtained in the same manner as in Example 1, except that the formulation was changed to that shown in Table 8 and drying was terminated when the content of methyl ethyl ketone in the mixture reached 0.2 mass %. Evaluation was carried out in the same manner as in Example 1.

[0185] Example 15 2.0 g of epoxy resin (A-1), 1.49 g of curing agent (B-1), 0.06 g of curing agent (D-1), 13.6 g of metal element-containing particles (C-1), and 54.4 g of magnetic particles (C-2) were mixed in a mixer to prepare a mixture of raw materials.

[0186] The raw material mixture was melt-mixed at 110°C for 1 minute using a kneader rotating at a low speed (10 rpm), and the resulting molten mixture was crushed to obtain a compound (CPD-8). Evaluation was carried out in the same manner as in Example 1.

[0187] [Evaluation] (Specific surface area of ​​metal element-containing particles) The specific surface area was measured using a fully automatic BET specific surface area measuring device HM model-1201 manufactured by Mountec Co., Ltd. ２ The measurement was performed using a mixed gas of 0.1% by volume of 0.1% by volume of 0.1% by volume of He / He as the adsorption gas. When two or more types of metal element-containing particles were included, the specific surface area was calculated as an average value for all the metal element-containing particles based on the specific surface area and content ratio of each metal element-containing particle.

[0188] (Varnish storage stability) The solution viscosity (initial viscosity) immediately after preparing a resin solution containing an epoxy resin, a curing agent (D) having an imidazole structure, and a curing agent (B) different from the curing agent having an imidazole structure, and the viscosity of the resin solution after storing it at 25°C for two weeks were measured at room temperature (25°C) using an E-type viscometer (TVE-35H, manufactured by Toki Sangyo Co., Ltd.), and the varnish thickening ratio was calculated using the following mathematical formula (1). In addition, a resin solution in which part or all of it had solidified after storage, making viscosity measurement impossible, was designated as "solidified."

[0189] Varnish thickening ratio (times) = Viscosity after 2 weeks storage at 25°C / Initial viscosity Formula (1) Ranks A and B were considered to be acceptable. <Evaluation criteria> A: The varnish thickening ratio was 1.0 times or more and less than 1.1 times. B: The varnish thickening ratio was 1.1 times or more and less than 1.3 times. C: The varnish thickening ratio was 1.3 times or more and less than 1.5 times. D: The varnish thickening ratio was 1.5 times or more.

[0190] (Mechanical strength of bonded magnet) The bonded magnet compound was filled into a molding die and compression molded for 1 minute at a molding pressure of 150 MPa using a hydraulic molding machine to obtain a compression molded body of 4 mm x 4 mm x 4 mm. The obtained compression molded body was heated in a constant temperature bath at 150°C for 30 minutes to produce a bonded magnet molded body.

[0191] The obtained bonded magnet molded body was placed in an Autograph AGS-H 5kN (manufactured by Shimadzu Corporation), and a compression pressure was applied at a crosshead speed of 1.0 mm / min. The maximum compression pressure at which the bonded magnet molded body broke was taken as the mechanical strength (MPa). Mechanical strength measurements were carried out at 25°C. Ranks A and B were rated as passing. <Evaluation criteria> A: The mechanical strength was 120 MPa or more. B: The mechanical strength was 100 MPa or more and less than 120 MPa. C: The mechanical strength was 80 MPa or more and less than 100 MPa. D: The mechanical strength was less than 80 MPa.

[0192] (Changes in properties due to heating during bonded magnet molding) The bonded magnet compound was heated in a constant temperature bath at 100°C for 30 minutes (an example of conditions for orienting magnetic particles), and the mechanical strength of the bonded magnet compound was measured after heating. Based on the mechanical strength before and after heating, the mechanical strength retention rate was calculated using the following formula (2), and used as an index of changes in properties due to heating during bonded magnet molding.

[0193] Mechanical strength retention rate = Mechanical strength using compound after heating at 100°C for 30 minutes / Mechanical strength × 100 Formula (2) Ranks A and B were considered to be acceptable. <Evaluation criteria> A: Mechanical strength retention rate was 70.0% or more. B: Mechanical strength retention rate was 60.0% or more and less than 70.0%. C: Mechanical strength retention rate was 50.0% or more and less than 60.0%. D: Mechanical strength retention rate was less than 50.0%.

[0194] (Heat and humidity resistance of bonded magnets) A bonded magnet molded body was left in a high-temperature, high-humidity environment (temperature 85°C, humidity 85%) for 7 days, and the mechanical strength of the bonded magnet molded body after leaving was measured. The bonded magnet molded body was produced in the same manner as described in the mechanical strength evaluation method. Based on the mechanical strength before and after leaving, the mechanical strength retention rate was calculated using the following formula (3) and used as an index of heat and humidity resistance. Mechanical strength retention rate (%) = Mechanical strength after leaving in a high-temperature, high-humidity environment for 7 days / Mechanical strength × 100 ... Formula (3) Ranks A and B were considered to be acceptable. <Evaluation criteria> A: Mechanical strength retention rate was 85.0% or more. B: Mechanical strength retention rate was 75.0% or more and less than 85.0%. C: Mechanical strength retention rate was 65.0% or more and less than 75.0%. D: Mechanical strength retention rate was less than 65.0%.

[0195] The compositions of the compounds of Examples 1 to 18 (CPD-1 to CPD-17 and CPD-32) and the compounds of Comparative Examples 1 to 14 (CPD-18 to CPD-31) are shown in Table 8 below, and the evaluation results are shown in Table 9 below.

[0196]

[0197]

[0198] As shown in Tables 8 and 9, examples of bonded magnet compounds containing epoxy resin (A), metal element-containing particles (C), and curing agent (D) having an imidazole structure, in which the curing agent (D) having an imidazole structure contains a compound represented by formula (1) and / or a compound represented by formula (2), had a long usable time in the manufacturing process, showed little change in properties due to heating during bonded magnet molding, and showed high mechanical strength even when the thermosetting resin was subjected to a curing reaction under low-temperature conditions.

[0199] On the other hand, the comparative example that did not contain the metal element-containing particles (C) and the specified curing agent (D) having an imidazole structure had a long usable time in the manufacturing process, showed a large change in properties due to heating during bonded magnet molding, and also showed poor mechanical strength when the thermosetting resin was cured under low temperature conditions.

[0200] The bonded magnet compound of this embodiment has industrial applicability as a material for various bonded magnets.

Claims

1. A compound comprising an epoxy resin (A), metal element-containing particles (C), and a curing agent (D) having an imidazole structure, wherein the curing agent (D) having an imidazole structure comprises a compound represented by the following formula (1) and / or a compound represented by the following formula (2): (In formulas (1) and (2), R １ and R ２ R is independently any one selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, and a cycloalkyl group having 6 to 20 carbon atoms which may have a substituent. １ and R ２ may be the same or different, R １ and R ２ may be bonded to form a condensed ring having no aromaticity. X is any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aralkyl group having 7 to 20 carbon atoms which may have a substituent, and a heteroarylalkyl group having 4 to 20 carbon atoms which may have a substituent. Y and Z are each independently any one selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and an acyl group having 1 to 20 carbon atoms which may have a substituent. Y and Z may be the same or different, and two or more Ys or two or more Zs may be bonded to form a monocyclic ring or a condensed ring. m and n are each independently an integer from 1 to 4.

2. The compound according to claim 1, wherein in the curing agent (D) having an imidazole structure, Y and Z are each independently one selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxyl group, an alkoxy group having 1 to 20 carbon atoms without a substituent, an alkyl group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, an alkoxy group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, an aryl group having 6 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, an aryloxy group having 6 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent, and an acyl group having 1 to 20 carbon atoms and having a hydroxyl group and / or a carboxyl group as a substituent.

3. In the curing agent (D) having an imidazole structure, the compound represented by the formula (1) is any one selected from the group consisting of 2-(2-hydroxyphenyl)imidazole, 2-(2-hydroxyphenyl)-4(5)-methylimidazole, 4-ethyl-(2-hydroxyphenyl)-5-methylimidazole, (2-hydroxyphenyl)-4-isopropyl-5-methylimidazole, 4-butyl-(2-hydroxyphenyl)-5-methylimidazole, and 2-(2-hydroxy-3(5)-methoxyphenyl)imidazole, and / or the compound represented by the formula (2) is The compound according to claim 1 or 2, which is any one selected from the group consisting of 2-(2-hydroxyphenyl)benzimidazole, 2-(2-hydroxy-3(5)-methoxyphenyl)benzimidazole, 2-(1-hydroxynaphthalen-2-yl)benzimidazole, 2-(2-hydroxynaphthalen-1-yl)benzimidazole, and 2-(2-hydroxyphenyl)benzimidazole-6-carboxylic acid.

4. The compound according to claim 1 or 2, further comprising a curing agent (B) different from the curing agent having an imidazole structure.

5. The compound according to claim 4, wherein the curing agent (B) different from the curing agent having an imidazole structure includes a curing agent that is solid at 25°C, and the content of the curing agent that is solid at 25°C is 50 mass% or more based on the total amount of the curing agents.

6. The compound according to claim 1 or 2, wherein the metal element-containing particles (C) are magnetic particles.

7. The compound of claim 6, wherein said magnetic particles are rare earth magnetic particles.

8. The compound according to claim 6, wherein the content of the magnetic particles is 70% by mass or more and 99.5% by mass or less based on the total mass of the compound.

9. The specific surface area of ​​the magnetic particles is 0.005 m ２ / g or more 5.0m ２ The compound of claim 6, wherein the molecular weight is less than or equal to 1 / g.

10. The compound according to claim 6, wherein (X) is the content (mass%) of the magnetic particles relative to the total mass of the compound, (Y) is the specific surface area of ​​the magnetic particles, and (Z) is the content (mass%) of the curing agent (D) having an imidazole structure relative to the total mass of the compound, (X), (Y) and (Z) satisfy the following formula (γ): 0.000010≦(Z) / (X)×(Y)≦0.30...(γ) 11. The compound according to claim 1, wherein the epoxy resin (A) contains a partial structure represented by the following formula (A1): (In formula (A1), R １ ~R ３ are each independently a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a heteroatom, or a substituent containing a halogen atom; R １ ~R ３ At least one of the groups contains a reactive group with the curing agent (D) having an imidazole structure, and R １ ~R ３ may be the same or different.) 12. The compound according to claim 1, wherein the epoxy resin (A) contains a partial structure represented by the following formula (A2): (In formula (A2), R １ , R ２ is an alkylene group having 1 to 12 carbon atoms, and m and n are each independently an integer of 1 or more. １ and G ２ is one selected from the group consisting of a hydrogen atom, an alkyl group, an aromatic group, a substituent containing a heteroatom, and a substituent containing a halogen atom. １ and G ２ may be the same or different.) 13. A compound according to claim 1 or 2, wherein the epoxy resin (A) contains an epoxy resin that is solid at 25°C, and the content of the epoxy resin that is solid at 25°C is 50 mass% or more based on the total amount of epoxy resins.

14. The compound according to claim 1 or 2, further comprising a compound (E) represented by the following formula (3): In formula (3), R １ ~R ８ R is independently one selected from the group consisting of hydrogen, an alkyl group, an aromatic group, a substituent containing a heteroatom, and a substituent containing a halogen atom. １ ~R ８ may be the same or different. ４ ~R ８ At least two selected from the group consisting of benzene rings may form a condensed ring with the adjacent benzene ring.

15. A varnish comprising an epoxy resin (A), a curing agent (D) having an imidazole structure, a curing agent (B) different from the curing agent having an imidazole structure, and an organic solvent (G), wherein the curing agent (D) having an imidazole structure comprises a compound represented by the following formula (1) and / or a compound represented by the following formula (2): (In formulas (1) and (2), R １ and R ２ R is independently any one selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, and a cycloalkyl group having 6 to 20 carbon atoms which may have a substituent. １ and R ２ may be the same or different, R １ and R ２ may be bonded to form a condensed ring having no aromaticity. X is any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aralkyl group having 7 to 20 carbon atoms which may have a substituent, and a heteroarylalkyl group having 4 to 20 carbon atoms which may have a substituent. Y and Z are each independently any one selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a carboxy group, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and an acyl group having 1 to 20 carbon atoms which may have a substituent. Y and Z may be the same or different, and two or more Ys or two or more Zs may be bonded to form a monocyclic ring or a condensed ring. m and n are each independently an integer from 1 to 4.

16. A bonded magnet obtained by molding and curing the compound according to any one of claims 1 to 16.

17. A motor including the bonded magnet according to claim 16.

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