Curable resin composition

Abstract

Disclosed is a curable resin composition which contains a curable resin and a phenolic compound. The phenolic compound has a structure represented by formula (1). (In the formula, X represents a direct bond, -CH2-, -CH=CH-, -C≡C-, -C(=O)-, -C(=O)-O-, -C(=O)-NH-, -CH=N-, -CH=N-N=CH-, -N=N-, -N+(-O-)=N-, -CH=C(CH3)-, -CH=C(CN)-, -CH=CH-C(=O)-, -Ph-C(=O)-, -Ph-CH2-, -Ph-, -Ph-Ph-, -S(=O)2-, -C(=O)O-R-O-C(=O)-, -O-C(=O)-R-C(=O)-O-, -C(=O)O-Ph-O-C(=O)-, or -O-C(=O)-Ph-C(=O)-O-, Ph represents an unsubstituted or substituted aromatic ring, Y represents a linear or branched alkylene chain having 1 to 20 carbon atoms, n represents an integer of 1 to 5, and R represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms.)

Description

Curable resin composition

[0001] The present invention relates to a curable resin composition.

[0002] As electronic devices become smaller and their performance improves, the amount of heat generated increases, creating a growing demand for improved heat dissipation in heat-dissipating resin sheets used in electronic devices. While the thermal conductivity of a heat-dissipating resin sheet can be improved by increasing the inorganic filler filling rate, increasing the inorganic filler filling rate leads to a problem of reduced flexibility, for example, in the B-stage state before curing. Reduced flexibility of a heat-dissipating resin sheet can lead to problems such as cracking when rolled up during storage or during the process of mounting on a substrate, etc. Due to these problems, there is a limit to how much the thermal conductivity of a heat-dissipating resin sheet can be improved simply by increasing the inorganic filler filling rate.

[0003] Meanwhile, studies have been conducted to improve thermal conductivity using a matrix resin alone or a combination of a matrix resin and a filler. For example, Patent Document 1 discloses an epoxy resin obtained by condensing a phenolic compound having a specific structure with a polyformylphenyl derivative, and having a weight-average molecular weight of 500 to 3,000. Furthermore, Patent Document 2 discloses a resin composition containing an epoxy resin monomer, a novolac resin containing a compound having a specific structural unit, and a filler having a particle size within a specific range.

[0004] International Publication No. 2015 / 060307 Japanese Patent Application Laid-Open No. 2013-18991

[0005] However, conventional heat-dissipating resin sheets are not sufficiently effective in improving the thermal conductivity of the matrix resin alone, and there is a demand for further improvement in the thermal conductivity of the matrix resin.

[0006] Therefore, an object of the present invention is to provide a curable resin composition that has excellent thermal conductivity after curing.

[0007] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by using a phenolic compound having a specific structure as a curing agent for a curable resin. That is, the present invention provides the following [1] to [4].

[0008] [1] A curable resin composition comprising a curable resin and a phenolic compound, wherein the phenolic compound has a structure represented by the following formula (1): (X is a direct bond, -CH=CH-, -C≡C-, -C(=O)-, -C(=O)-O-, -C(=O)-NH-, -CH=N-, -CH=N-N=CH-, -N=N-, -N ＋ (-O － )=N-, -CH=C(CH ３ )-, -CH=C(CN)-, -CH=CH-C(=O)-, -Ph-C(=O)-, -Ph-, -Ph-Ph-, -S(=O) ２ -, -C(=O)OR Ａ -OC(=O)-, -OC(=O)-R Ａ represents -C(=O)-O-, -C(=O)O-Ph-O-C(=O)-, or -O-C(=O)-Ph-C(=O)-O-, where Ph represents an unsubstituted or substituted aromatic ring, Y represents a linear or branched alkylene chain having 1 to 20 carbon atoms, n represents an integer of 2 to 5, and R Ａ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms.) [2] The curable resin composition according to [1], further comprising a thermally conductive filler and an epoxy resin as the curable resin. [3] The curable resin composition according to [1] or [2], wherein the curable resin is an epoxy resin having a mesogenic skeleton. [4] A cured product of the curable resin composition according to any one of [1] to [3].

[0009] According to the present invention, it is possible to provide a curable resin composition that has excellent thermal conductivity after curing.

[0010] The present invention will be described below with reference to embodiments. The curable resin composition of the present invention contains a curable resin and a phenol compound having a specific structure described below.

[0011] <Phenol Compound> The curable resin composition of the present invention contains a phenol compound (hereinafter also simply referred to as "phenol compound") having a structure represented by the following formula (1): In the curable resin composition, the phenol compound serves as a curing agent that cures the curable resin described below. (X is a direct bond, -CH=CH-, -C≡C-, -C(=O)-, -C(=O)-O-, -C(=O)-NH-, -CH=N-, -CH=N-N=CH-, -N=N-, -N ＋ (-O － )=N-, -CH=C(CH ３ )-, -CH=C(CN)-, -CH=CH-C(=O)-, -Ph-C(=O)-, -Ph-, -Ph-Ph-, -S(=O) ２ -, -C(=O)OR Ａ -OC(=O)-, -OC(=O)-R Ａ represents -C(=O)-O-, -C(=O)O-Ph-O-C(=O)-, or -O-C(=O)-Ph-C(=O)-O-, where Ph represents an unsubstituted or substituted aromatic ring, Y represents a linear or branched alkylene chain having 1 to 20 carbon atoms, n represents an integer of 2 to 5, and R Ａ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms.

[0012] In the phenolic compound, n may be the same or different in the aromatic rings on both sides. However, from the viewpoint of further improving the thermal conductivity of the phenolic compound as a symmetrical structure, it is preferable that n in the aromatic rings on both sides be the same. Note that n is the number of hydroxyl groups per aromatic ring. When n is 2 or more, as shown in the formulas (1-a) and (1-c) described below, all hydroxyl groups may be bonded to positions adjacent to each other. Alternatively, as shown in formula (1-d), hydroxyl groups bonded to distant positions and hydroxyl groups bonded to adjacent positions may be mixed. Furthermore, as shown in formulas (1-b) and (1-e), all hydroxyl groups may be bonded to positions distant from each other, but it is preferable that at least one pair of hydroxyl groups be bonded to positions adjacent to each other.

[0013] The phenol compound preferably has a structure where n is 2 to 3, more preferably has a structure where n is 2, and even more preferably has a structure where n is 2 in all aromatic rings. In formula (1), examples of the substituent in Ph include a halogen atom, an alkyl group having about 1 to 8 carbon atoms, a nitrile group, and a phenyl group. In formula (1), specific examples of Ph include a substituted or unsubstituted phenylene group and a substituted or unsubstituted naphthalene group. Ph is preferably a substituted or unsubstituted phenylene group, and more preferably an unsubstituted phenylene group. In addition, the bonding position of the phenylene group is not particularly limited, but is preferably the para position.

[0014] When there are two hydroxyl groups, specifically, structures represented by the following formulas (1-a) and (1-b) are preferred. When there are three hydroxyl groups, it is preferable that the compound has a structure represented by the following formula (1-c) to formula (1-e).

[0015] Among the above-mentioned phenol compounds, those having a structure in which two hydroxyl groups are bonded to the meta position and the para position, respectively, with respect to the bonding position of X, and are bonded so as to be adjacent to each other, as represented by the above formula (1-a).

[0016] In the curable resin composition, when a phenolic compound reacts with a curable resin, the hydroxyl groups in the phenolic compound become reaction sites with the curable resin, but as described above, because the hydroxyl groups are bonded so as to be adjacent to each other, the molecules of the curable resin after the reaction become close to each other, resulting in so-called stacking. This improves the molecular alignment of the curable resin, making it easier to impart excellent thermal conductivity to the cured product of the curable resin composition.

[0017] In formulas (1), (1-a) to (1-e), X can improve the planarity of the phenolic compound. By improving the planarity of the phenolic compound, when the curable resin and the phenolic compound react, the molecular alignment of the curable resin is improved, and the thermal conductivity of the cured product of the curable resin composition can be improved. X includes a direct bond, -C(=O)-, -C(=O)-O-, -C(=O)-NH-, -Ph-C(=O)-, -Ph-, -Ph-Ph-, and -C(=O)O-R. Ａ -OC(=O)-, -OC(=O)-R Ａ At least one selected from -C(=O)-O-, -C(=O)O-Ph-O-C(=O)-, and -O-C(=O)-Ph-C(=O)-O- is preferred, at least one selected from a direct bond, -C(=O)-, and -Ph-C(=O) is more preferred, and a direct bond or -C(=O)- is even more preferred. Note that each of the two bonds of each X may be bonded to either Y or an aromatic ring having a hydroxyl group, but when X has Ph, it is preferred that Ph of X be bonded to an aromatic ring having a hydroxyl group from the viewpoint of improving planarity.

[0018] In addition, in formulas (1), (1-a) to (1-e), the two Xs may be the same group or different groups, but are preferably the same group. When the two Xs are the same group, it is more preferable that the phenol compound is symmetrical with respect to Y, from the viewpoint of easily improving the thermal conductivity of the cured product of the curable resin composition. Note that being symmetrical means that the structures consisting of a pair of Xs and an aromatic ring having a hydroxyl group, with Y at the center, are all the same.

[0019] In formulas (1) and (1-a) to (1-e), Y can improve the mobility and flexibility of the phenolic compound. By improving the mobility and flexibility of the phenolic compound, the reaction proceeds while the curable resin and the phenolic compound are aligned, resulting in good molecular alignment in the cured product after the reaction, and imparting excellent thermal conductivity to the cured product of the curable resin composition. Specific examples of Y, if linear, include a methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, and pentadecamethylene group. Examples of branched alkylene chains include propylene, sec-butylene, tert-butylene, iso-butylene, iso-pentylene, tert-pentylene, 2-hexylene, 3-hexylene, 2-heptylene, 3-heptylene, iso-heptylene, tert-heptylene, iso-octylene, tert-octylene, and 2-ethylhexylene. Y is preferably a linear or branched alkylene chain having 2 to 15 carbon atoms, more preferably a linear or branched alkylene chain having 3 to 10 carbon atoms, and even more preferably a linear or branched alkylene chain having 4 to 9 carbon atoms. Furthermore, Y is even more preferably a linear chain from the viewpoint of ensuring the rotation of Y, thereby making it easier to improve the mobility and flexibility of the phenol compound.

[0020] The phenol compound is preferably one represented by the following formulas (1-f) to (1-j), more preferably one represented by the following formulas (1-f) to (1-i). Furthermore, one represented by (1-g) or (1-h) is even more preferable. In (1-g) or (1-h), the chain between the two aromatic rings has a linear aliphatic skeleton, and compared with compounds such as (1-f), (1-i), and (1-j) which have a carbonyl group, they have a lower melting point, excellent solvent solubility, and are easier to handle. In the above formulas (1-f) to (1-j), p is an integer of 1 to 20, preferably an integer of 2 to 15, more preferably an integer of 3 to 12, and even more preferably an integer of 4 to 10. Furthermore, q is an integer of 0 to 18, preferably an integer of 0 to 13, more preferably an integer of 1 to 10, and even more preferably an integer of 2 to 8.

[0021] (Method for Producing Phenol Compound) A phenol compound can be obtained by bonding a compound having a basic skeleton of X-Y-X (X and Y are as described above) like the compound shown in formula (2) below, or a compound having a structure that serves as a precursor of the basic skeleton of X-Y-X, with a compound shown in formula (3) below or a derivative thereof by a Friedel-Crafts reaction, a cross-coupling reaction, or the like. Note that when the phenol compound is obtained by a Friedel-Crafts reaction, a cross-coupling reaction, or the like, it may be obtained by another reaction in addition to the Friedel-Crafts reaction or the cross-coupling reaction.

[0022] In formula (2), M represents a halogen atom, and X and Y are as described above. However, in order to ensure a proper Friedel-Crafts reaction, it is preferable that X has a structure in which it is bonded to an acyl group or a saturated hydrocarbon group, such as a direct bond, -C(=O)-, -C(=O)-NH-, -CH=CH-C(=O)-, or -Ph-C(=O)-. From the viewpoint of reactivity, it is more preferable that X is -C(=O)-. Furthermore, it is preferable that M is a chlorine atom or a bromine atom, with a chlorine atom being more preferable.

[0023] In the formula (3), n is as described above. Ｂ is a protective group for a hydroxyl group, preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group.

[0024] Specific examples of the compound represented by formula (2) include adipoyl chloride, azelayl chloride, dodecandioyl dichloride, suberyl dichloride, sebacoyl chloride, etc. Among these, adipoyl chloride or sebacoyl chloride is preferred, and adipoyl chloride is more preferred.

[0025] Specific examples of the compound represented by formula (3) include anisole, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, 1,2,3-trimethoxybenzene, 1,2,4-trimethoxybenzene, 1,3,5-trimethoxybenzene, tetramethoxybenzene, pentamethoxybenzene, etc. Among these, 1,2-dimethoxybenzene is preferred.

[0026] In the method using the Friedel-Crafts reaction, when X has an acyl group and M is bonded to the acyl group, a reduction reaction to convert the acyl group to a methylene group may be carried out after the Friedel-Crafts reaction. Examples of the reduction reaction include the Wolff-Kischner reduction reaction using hydrazine and a reduction reaction using a palladium carbon catalyst. By carrying out this reduction reaction, a phenol compound can be easily obtained even when X is a direct bond. In addition, when the Friedel-Crafts reaction is carried out, a protecting group R B In the case where the Friedel-Crafts reaction or the reduction reaction described above is carried out, the deprotection reaction is preferably carried out after the reduction reaction.

[0027] The melting point of the phenol compound is preferably 0°C or higher and 300°C or lower, more preferably 10°C or higher and 250°C or lower, and even more preferably 20°C or higher and 200°C or lower. When the melting point of the phenol compound is above the above lower limit, orientation is facilitated during the thermal curing process, and a cured product with excellent thermal conductivity is obtained. Furthermore, when the melting point of the phenol compound is below the above upper limit, solvent solubility is excellent and handling is facilitated. The melting point of the phenol compound may be measured as the temperature of the endothermic peak when the temperature is raised at 5°C / min using a differential scanning calorimeter, and detailed measurement methods are as described in the Examples.

[0028] The curable resin composition of the present invention may contain a curing agent other than the phenolic compound, as long as the effects of the present invention are not significantly impaired. The curing agent other than the phenolic compound is a compound that can react with the curable resin described below to cure the curable resin. The content of the curing agent other than the phenolic compound in the curable resin composition is, for example, less than 50 equivalent%, preferably 30 equivalent% or less, and more preferably 10 equivalent% or less, when the total amount of phenolic compounds contained in the curable resin composition is 100 equivalent%. The curable resin composition of the present invention does not need to contain a curing agent other than the phenolic compound.

[0029] <Curable Resin> The curable resin composition of the present invention contains a curable resin. The curable resin is preferably a thermosetting resin. As the curable resin, a resin capable of reacting with the above-mentioned phenolic compound may be used. Examples of thermosetting resins capable of reacting with phenolic compounds include thermosetting urethane resins, epoxy resins, benzoxazine resins, and bismaleimide resins. Among these, at least one selected from epoxy resins, benzoxazine resins, and bismaleimide resins is preferred, and epoxy resins are more preferred.

[0030] The epoxy resin may be, for example, a compound containing two or more epoxy groups in the molecule, and may have a weight average molecular weight of, for example, less than 10,000, preferably 5,000 or less. Specific examples of epoxy resins include styrene skeleton-containing epoxy resins, resorcinol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol E-type epoxy resins, bisphenol S-type epoxy resins, 2,2'-diallyl bisphenol A-type epoxy resins, hydrogenated bisphenol-type epoxy resins, propylene oxide-added bisphenol A-type epoxy resins, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, biphenol-type epoxy resins, phenoxy-type epoxy resins, naphthalene-type epoxy resins, biphenyl-type epoxy resins, phenylene ether-type epoxy resins, fluorene-type epoxy resins, phenol aralkyl-type epoxy resins, naphthol aralkyl-type epoxy resins, naphthylene ether-type epoxy resins, dicyclopentadiene-type epoxy resins, anthracene-type epoxy resins, epoxy resins having a mesogen skeleton, epoxy resins having an adamantane skeleton, epoxy resins having a tricyclodecane skeleton, and epoxy resins having a triazine nucleus in the skeleton, glycidylamine-type epoxy resins, and glycidyl ester-type epoxy resins.

[0031] When an epoxy resin is used as the curable resin, the epoxy resin may be contained in the curable resin composition so that the equivalent ratio of the hydroxyl groups contained in the phenol compound to the epoxy groups contained in the epoxy resin (hydroxyl groups / epoxy groups) is, for example, 0.5 or more and 2 or less. The equivalent ratio is preferably 0.6 or more / 1.8 or less, more preferably 0.7 or more and 1.6 or less, and even more preferably 0.8 or more / 1.4 or less. By setting the equivalent ratio to a value close to 1, the curable resin and the phenol compound can be appropriately reacted to obtain a good cured product.

[0032] The epoxy resin used in the present invention is preferably an epoxy resin having a mesogenic skeleton. The mesogenic skeleton is a molecular structure that can exhibit liquid crystallinity, which improves alignment after curing and makes it easier to impart excellent thermal conductivity to the cured product of the curable resin composition. The epoxy resin having a mesogenic skeleton preferably has two or more epoxy groups in one molecule, with the number of epoxy groups in one molecule more preferably 2 to 4, and even more preferably 2. Having two epoxy groups makes it easier to improve alignment after curing, which in turn makes it easier to improve thermal conductivity.

[0033] An example of a structure having a mesogenic skeleton is the structure of the following formula (4). In formula (4), * is independently a bond to a group containing an epoxy group or a bond to a linking group bonded to another mesogenic skeleton, k is an integer of 0 to 4, and β is independently —R, —OR, a halogen atom, —CN, or —NO ２ , and -COCH ３ R is an aliphatic hydrocarbon group having 1 to 8 carbon atoms. α is at least one selected from the group represented by the following formula (A):

[0034] In group (A), n is an integer of 0 to 4, s is an integer of 0 to 7, m is an integer of 0 to 8, l is an integer of 0 to 12, and r is an integer of 0 to 8. β is as described above.

[0035] In formula (4), the bonding position indicated by * is preferably the para position relative to α, that is, the structure shown in formula (4) is preferably the following formula (4-1). In the formula (4-1), *, α, β, and k are as described above.

[0036] In formulas (4) and (4-1), β is preferably a halogen atom or an alkyl group, more preferably an alkyl group. The halogen atom is any one of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The alkyl group may be linear, branched, or cyclic, but is preferably linear. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, and an n-octyl group, and among these, a methyl group is preferred. k is preferably 0 to 2. n is preferably 0 to 2. s is preferably 0 to 5, more preferably 0 to 2. m is preferably 0 to 4, more preferably 0 to 2. l is preferably 0 to 6, more preferably 0 to 3. r is preferably 0 to 4, more preferably 0 to 2, and most preferably 0.

[0037] In formula (4) or formula (4-1), the mesogenic skeleton is preferably one in which α is a single bond or a group containing —COO—, and among these, a biphenyl skeleton in which α is a single bond, a phenylbenzoate skeleton in which α is a group containing —COO—, or a skeleton represented by the following formula (X) is more preferred. In the formula (X), β, k, n, and * are as defined above, but it is preferable that each * is a bond to a group containing an epoxy group.

[0038] In formulas (4), (4-1), and (X), the epoxy group-containing group bonded to * is preferably an organic group containing an epoxy group having about 2 to 20 carbon atoms, more preferably an organic group containing an epoxy group having 3 to 12 carbon atoms, and even more preferably a group represented by the following formula (5). When the epoxy group-containing group is a group represented by the following formula (5), synthesis of an epoxy resin having a mesogenic skeleton becomes easy.

[0039] In formula (5), * represents a bond to the aromatic ring of the mesogenic skeleton. １represents a linear or branched alkylene group having 1 to 10 carbon atoms. Examples of the linear or branched alkylene group include a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, and a decamethylene group. Of these, a methylene group, an ethylene group, a trimethylene group, or a tetramethylene group is preferred.

[0040] In addition, it is preferable that in the epoxy resin having a mesogenic skeleton, both * in the above formulas (4) and (4-1) are bonded to a group represented by formula (5). Therefore, the epoxy resin having a mesogenic skeleton preferably has a structure represented by the following formula (4-2). In addition, in formula (4-2), R １ , α, β, and k are as described above.

[0041] In the above formulas (4) and (4-1), the linking group bonded to * may be an organic group having about 1 to 24 carbon atoms, preferably an organic group having 3 to 16 carbon atoms, and more preferably an organic group having 4 to 12 carbon atoms. In the above formulas (4) and (4-1), when at least one of * is bonded to a linking group that is bonded to another mesogenic skeleton, the epoxy resin having a mesogenic skeleton will have multiple mesogenic skeletons in one molecule, and in this case, it is preferable that there are two mesogenic skeletons in one molecule. In the above formulas (4) and (4-1), the "another mesogenic skeleton" may be either of the skeletons represented by formulas (4) and (4-1), respectively. The two or more mesogenic skeletons in one molecule may be the same or different, but from the viewpoint of ease of production, they are preferably the same.

[0042] In the above formulas (4) and (4-1), it is also preferable that one of the *'s is bonded to a group containing an epoxy group, and the other is bonded to a linking group that is linked to another mesogenic skeleton. In this case, the group containing an epoxy group is as described above, and among them, a group represented by formula (5) is preferred. Therefore, it is also preferable that the epoxy resin having a mesogenic skeleton has a structure represented by the following formula (4-3). The structure represented by the following formula (4-3) is a structure represented by R ２ By having a linking group represented by the formula: the thermal conductivity is likely to be improved.

[0043] In the formula (4-3), α, β, k, and R １ is as described above. ２ is a divalent organic group, and R ２ The number of carbon atoms in R is, for example, 1 to 24, preferably 2 to 16, and more preferably 3 to 12. ２ More specifically, R is a hydrocarbon group which may have a heteroatom such as an oxygen atom, a nitrogen atom, or a sulfur atom. As the heteroatom, an oxygen atom is preferred, and among these, an oxygen atom constituting an ether bond is preferred. ２ From the viewpoint of ease of synthesis, *-O-R ４ A group represented by —O-* is preferred, where * is a bond to the phenyl ring, and R ４ is an aliphatic hydrocarbon group having 1 to 24 carbon atoms, and is preferably a saturated aliphatic hydrocarbon group. ４ R may be linear, branched, or cyclic, but is preferably linear. ４ The number of carbon atoms in R is, for example, 1 to 24, preferably 2 to 16, more preferably 3 to 12, and even more preferably 6 to 12. ４ is preferably a linear or branched alkylene group. ４Specific examples of the alkyl group include an ethylene group, a propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group, an undecamethylene group, a dodecamethylene group, a tridecamethylene group, a tetradecamethylene group, a pentadecamethylene group, a hexadecamethylene group, and a heptadecamethylene group, and among these, an octamethylene group is particularly preferred.

[0044] The epoxy resin having a mesogenic skeleton is also preferably a compound represented by the following formula (5-1), (5-2), or (5-3). Among these, the compound represented by formula (5-1) is preferred from the viewpoint of ease of production of the epoxy resin, and the compound represented by formula (5-3) is preferred from the viewpoint of improving thermal conductivity. In addition, in formula (5-1), R ６ are each independently an alkyl group or a hydrogen atom. The alkyl group is as described above, but is preferably a methyl group. ３ is an alkylene group having 1 to 10 carbon atoms, preferably an alkylene group having 1 to 5 carbon atoms, and more preferably at least one selected from a methylene group and an ethylene group.

[0045] In addition, in formula (5-2), R ３ and R ４ is as above.

[0046] In addition, in formula (5-3), R ５ is preferably an alkylene group having 1 to 15 carbon atoms, more preferably an alkylene group having 2 to 10 carbon atoms, and even more preferably an alkylene group having 3 to 5 carbon atoms.

[0047] Furthermore, as the epoxy resin having a mesogenic skeleton, for example, compounds described in the non-patent document Macromol. Chem. Phys. 1998, 199, 853. and the patent documents Japanese Patent Nos. 4118691, 5397476, 547195, and 7024777 are also preferred.

[0048] The epoxy resin having a mesogenic skeleton may be in the state of a prepolymer obtained by reacting a part of it with a curing agent, etc. The curing agent may be the above-mentioned phenolic compound, but is not limited to phenolic compounds and may be any of amine-based curing agents, acid anhydride-based curing agents, mercaptan-based curing agents, imidazole-based curing agents, etc.

[0049] The weight-average molecular weight of the epoxy resin having a mesogenic skeleton is preferably less than 10,000, more preferably 5,000 or less, and even more preferably 3,000 or less. The weight-average molecular weight of the epoxy resin having a mesogenic skeleton is not particularly limited, but may be, for example, 200 or more, preferably 250 or more. The weight-average molecular weight is a weight-average molecular weight measured in terms of polystyrene by gel permeation chromatography (GPC). Tetrahydrofuran is preferably used as an eluent in gel permeation chromatography (GPC) measurements. However, when the molecular weight is low, 1,000 or less, the weight-average molecular weight may be calculated from the structural formula. In addition, although the epoxy resin in the curable resin composition may undergo a reaction upon curing, the weight-average molecular weight refers to the weight-average molecular weight of the epoxy resin in a state before curing.

[0050] The epoxy equivalent of the epoxy resin having a mesogenic skeleton is not particularly limited, but is, for example, 100 g / eq or more and 1000 g / eq or less. The epoxy equivalent of the epoxy resin is preferably 120 g / eq or more, more preferably 140 g / eq or more, and is preferably 500 g / eq or less, more preferably 400 g / eq or less. The epoxy equivalent can be measured, for example, according to the method specified in JIS K 7236.

[0051] In the curable resin composition, the content of the epoxy resin having a mesogenic skeleton is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more, based on the total amount of the resin components constituting the curable resin composition. The epoxy resin having a mesogenic skeleton may be used alone or in combination of two or more.

[0052] When the curable resin composition contains an epoxy resin having a mesogenic skeleton, it may further contain an epoxy resin not having a mesogenic skeleton and a curable resin other than an epoxy resin (hereinafter collectively referred to as "other resins"). The epoxy resin not having a mesogenic skeleton may have one or more epoxy groups, preferably two or more. From the viewpoint of thermal conductivity, the content of the other resin in the curable resin composition is preferably low, and is, for example, less than 100 parts by mass, preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 15 parts by mass or less, relative to 100 parts by mass of the epoxy resin having a mesogenic skeleton. The fewer the other resins, the better.

[0053] <Filler> The curable resin composition of the present invention may contain a filler. The filler is preferably an inorganic filler having thermal conductivity. By containing the filler, the curable resin composition is more likely to have higher thermal conductivity of a cured product of the curable resin composition. The filler may be dispersed in a matrix component formed by a reaction between the curable resin and the phenol compound.

[0054] From the viewpoint of increasing the thermal conductivity of the curable resin composition, the thermal conductivity of the filler is, for example, 10 W / (m·K) or more, preferably 15 W / (m·K) or more, and more preferably 20 W / (m·K) or more. The thermal conductivity of the filler is not particularly limited, but may be, for example, 2000 W / (m·K) or less, or 1000 W / (m·K) or less. The thermal conductivity of the filler can be measured, for example, by a cyclic heating thermoreflectance method using a thermal microscope manufactured by Bethel Co., Ltd., on a filler cross section machined with a cross-section polisher.

[0055] The filler may have electrical insulation properties, and the electrical resistivity may be, for example, 10 ８ It is preferable that the filler has a resistance of Ω·m or more. High electrical insulation properties make it suitable for use in electronic devices such as substrates. Therefore, it is preferable that the filler is a thermally conductive filler that has electrical insulation properties.

[0056] Examples of fillers include metals, metal oxides, metal nitrides, metal hydroxides, carbon materials, oxides, nitrides, and carbides other than metals. The filler may be shaped in any form, such as flakes, spheres, crushed particles, irregular shapes, polyhedral shapes, or fibers, or may be in the form of aggregated particles formed by aggregation of primary particles. For example, boron nitride, which will be described later, is preferably used as aggregated particles. Examples of metals in fillers include aluminum, copper, and nickel; examples of metal oxides include aluminum oxide (e.g., alumina), magnesium oxide, and zinc oxide; and examples of metal nitrides include aluminum nitride. Examples of metal hydroxides include aluminum hydroxide. Examples of carbon materials include spherical graphite, flake graphite, and carbon fibers. Examples of oxides, nitrides, and carbides other than metals include quartz, boron nitride, and silicon carbide. Among these, from the viewpoint of ensuring electrical insulation, at least one selected from metal oxides, metal nitrides, metal hydroxides, oxides other than metals, nitrides, and carbides is preferred, and at least one selected from metal oxides, metal hydroxides, and nitrides is more preferred. Specifically, at least one selected from aluminum oxide, aluminum hydroxide, and boron nitride is even more preferred. The filler may be used alone or in combination of two or more of the above.

[0057] The average particle size of the filler is preferably 0.1 μm or more and 200 μm or less, more preferably 0.5 μm or more and 150 μm or less, and even more preferably 1 μm or more and 110 μm or less. It is also preferable to use, for example, a small-particle filler having an average particle size of 0.1 μm or more and 5 μm or less in combination with a large-particle filler having an average particle size of more than 5 μm and 200 μm or less. By using fillers with different average particle sizes, the filler filling rate in the curable resin composition can be increased. The average particle size of the filler can be measured by observation with an electron microscope or the like. More specifically, for example, the particle sizes of 50 particles of any thermally conductive filler can be measured using an electron microscope or optical microscope, and the average particle size (arithmetic mean value) can be used as the average particle size. For example, when the filler is an agglomerated particle as described above, the average particle size of the agglomerated particles may be within the above range.

[0058] The content of the filler is not particularly limited, but from the viewpoint of improving heat dissipation, it is, for example, 30% by mass or more, preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more in the curable resin composition. Furthermore, the content of the filler is not particularly limited, but in order to contain a certain amount or more of the curable resin and phenol compound, it is sufficient that it is 98% by mass or less, preferably 96% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less.

[0059] (Curing Accelerator) The curable resin composition of the present invention may contain a curing accelerator. By containing a curing accelerator, the curability of the curable resin composition can be enhanced. The curing accelerator is not particularly limited, and examples thereof include imidazole-based curing accelerators and tertiary amine-based curing accelerators. Of these, it is preferable to use an imidazole-based curing accelerator. Examples of imidazole-based curing accelerators include 1-cyanoethyl-2-phenylimidazole in which the 1-position of imidazole is protected with a cyanoethyl group, and imidazole-based curing accelerators in which basicity is protected with isocyanuric acid. Examples of commercially available products include 2MA-OK, 2MZ, 2MZ-P, 2PZ, 2PZ-PW, 2P4MZ, C11Z-CNS, 2PZ-CN, 2PZ-CNS, 2PZCNS-PW, 2MZ-A, 2MZA-PW, C11Z-A, 2E4MZ-A, 2MAOK-PW, 2PZ-OK, 2MZ-OK, 2PHZ, 2PHZ-PW, 2P4MHZ, 2P4MHZ-PW, 2E4MZ-BIS, VT, VT-OK, MAVT, and MAVT-OK (all manufactured by Shikoku Chemicals Corporation). Examples of organic phosphine compounds include triphenylphosphine, tetraphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tri-tert-butylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, and triphenylphosphine triphenylborane. Specific examples of organic phosphine compounds include TPP, TPP-MK, TPP-K, TTBuP-K, TPP-SCN, and TPP-S (all manufactured by Hokko Chemical Industry Co., Ltd.). These curing accelerators may be used alone or in combination of two or more. The content of the curing accelerator is, for example, 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, and more preferably 0.5 to 3 parts by mass, per 100 parts by mass of the combined amount of the curable resin and the phenolic compound.

[0060] (Coupling Agent) The curable resin composition of the present invention may contain a coupling agent. Examples of coupling agents include silane coupling agents and titanium coupling agents, with silane coupling agents being preferred. Known silane coupling agents may be used without particular limitation, and examples thereof include dimethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, n-decyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane. The silane coupling agents may be used alone or in combination of two or more. By including a silane coupling agent in the curable resin composition, when a filler is contained, the filler can be more easily dispersed, resulting in a high filler loading and improved thermal conductivity. The content of the coupling agent in the curable resin composition is, for example, 0.1 mass % or more and 10 mass % or less, preferably 0.3 mass % or more and 5 mass % or less, and more preferably 0.5 mass % or more and 3 mass % or less, based on the total amount of the curable resin composition.

[0061] [Other Components] In addition to the above components, the curable resin composition of the present invention may contain other additives such as a flame retardant, an antioxidant, a tackifier, a plasticizer, a thixotropy-imparting agent, a colorant, etc. Furthermore, a solvent may be blended into the curable resin composition during its production method, and it is preferable that a portion of the blended solvent remains in the curable resin composition.

[0062] As described in the production method below, the curable resin composition of the present invention contains a curable resin and a phenolic compound, and may be uncured or semi-cured and in a B-stage state. When the curable resin composition is in an uncured or B-stage state, it has high adhesion to another member and can be bonded to another member with high adhesive strength.

[0063] [Thermal Conductivity] When the mixture of the curable resin and the phenolic compound contained in the thermally conductive composition is cured, the thermal conductivity of the matrix component is preferably 0.17 W / (m·K) or more. A thermal conductivity of 0.17 W / (m·K) or more of the cured product improves heat dissipation. From the viewpoint of heat dissipation, the thermal conductivity is more preferably 0.22 W / (m·K) or more, and even more preferably 0.30 W / (m·K) or more. The upper limit of the thermal conductivity of the matrix component is not particularly limited, but in practice, it is, for example, about 1 W / (m·K). The thermal conductivity can be determined by measuring the thermal conductivity of a cured product obtained by mixing the curable resin and the phenolic compound in the proportions contained in the thermally conductive composition and curing the mixture as described in the examples below.

[0064] (Method for producing curable resin composition) The curable resin composition can be obtained by mixing a curable resin, a phenolic compound, and optionally a curing agent other than the phenolic compound, a filler, a curing accelerator, a coupling agent, and other additives. The curable resin composition may also be diluted with a dilution solvent such as an organic solvent.

[0065] (Method of Using Curable Resin Composition) The curable resin composition may be cured and used as a cured product. The curable resin composition may be used for various purposes, for example, in a heat dissipation member. The heat dissipation member may be used, for example, in an electronic device. The curable resin composition of the present invention has a high thermal conductivity of the matrix component after curing, so that high heat dissipation can be ensured when used inside an electronic device. More specifically, the heat dissipation member is disposed on an electronic component and used to dissipate heat generated by the electronic component. Furthermore, the heat dissipation member of the present invention is preferably disposed and used so as to fill the gap between two opposing components. The two opposing components may be, for example, one electronic component and the other a thermal conductor such as a heat sink for dissipating heat from the electronic component, a housing for an electronic device, a substrate, or the like.

[0066] The electronic component for which the curable resin composition is used is not particularly limited, but is preferably a semiconductor device, and more preferably a power module that requires high heat dissipation. The power module is used, for example, in an inverter. The power module is used, for example, in industrial equipment such as elevators and uninterruptible power supplies (UPS), but its use is not particularly limited. The curable resin composition may also be used as a part of a circuit board, or as an encapsulant for electronic components for embedding electronic components composed of semiconductor chips or the like inside.

[0067] The curable resin composition may be used in any form. It may be formed into a predetermined shape such as a thin film, sheet, or block by coating, casting, potting, extrusion molding, or the like, and then cured. Alternatively, it may be formed into an irregular shape and then cured. The curable resin composition may be coated or laminated on a support such as a release sheet, metal foil, or substrate, and dried by heating or the like as necessary to form a sheet, which may then be placed on an electronic component formed into a sheet. In this case, the curable resin composition may be cured after being placed on the electronic component, or may be cured before being placed on the electronic component. Alternatively, the curable resin composition may be placed on an electronic component or a thermal conductor by coating, casting, potting, or the like, and then cured to be used as a heat dissipation member.

[0068] The heating temperature when curing the curable resin composition is not particularly limited, and may be, for example, in the range of from 70° C. to 240° C., preferably from 120° C. to 220° C., and more preferably from 160° C. to 210° C. The heating time may be, for example, from 0.5 hours to 24 hours, preferably from 1 hour to 18 hours, and more preferably from 2 hours to 12 hours. When heating for curing, appropriate pressure may be applied, and for example, the composition may be heated and cured under pressurized or negative pressure, which makes it easier to bond to other members with high adhesive strength when cured.

[0069] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0070] The methods for measuring and evaluating each physical property are as follows.

[0071] [Thermal Conductivity] The thermal conductivity in the thickness direction of the cured resin products obtained in each of the Examples and Comparative Examples was measured using a thermal diffusivity measuring device ("ai-Phase Mobile M3" manufactured by ai-Phase Corporation).

[0072] [Melting Point] The melting points of the curing agents obtained in Synthesis Examples 2 to 5 were measured using a DSC (differential scanning calorimeter) as the endothermic peak temperature when the temperature was increased at a rate of 5°C / min. The differential scanning calorimeter used was an EXSTAR DSC7020 (manufactured by SSI NanoTechnology Inc.).

[0073] The components used in the examples and comparative examples are as follows: (Epoxy) Mesogen: Epoxy resin having a mesogen skeleton of the following structure, molecular weight 622 Biphenyl: "YL6121HA", manufactured by Mitsubishi Chemical Corporation, an epoxy resin having a mesogen skeleton with the following structure, molecular weight 326 Bisphenol A: Epoxy resin represented by the following structure, "YD-127", manufactured by Nippon Steel Chemical Co., Ltd., bisphenol A type epoxy resin

[0074] Among the above epoxies, the mesogen was obtained according to Synthesis Example 1 below. [Synthesis Example 1] (Procedure 1) 10.0 g (100 mmol) of 5-hexen-1-ol and 24.5 g (240 mmol) of triethylamine were added to a 200 mL recovery flask, stirred in an ice bath, and cooled to 0°C to obtain Solution A. A solution prepared by dissolving 24.8 g (130 mmol) of p-toluenesulfonyl chloride in 81 mL of dichloromethane was added dropwise to Solution A and stirred for 18 hours to obtain Reaction Solution B. Reaction Solution B was subjected to suction filtration, and 100 mL of water was added to the filtrate and stirred. The organic layer was then extracted with diethyl ether. The organic layer was washed successively with 1 mol / L hydrochloric acid, saturated saline, saturated aqueous sodium bicarbonate, and saturated saline, and then dried over magnesium sulfate. Thereafter, the solvent was distilled off from the solution under reduced pressure to obtain 22.3 g of Hex-5-en-1-yl4-methylbenzenesulfonate. The yield was 88%. １ H-NMR (400MHz, CDCl ３ ), １３ C-NMR (400MHz, CDCl ３ The structure was confirmed by IR (KBr, v). The reaction formula for step 1 is as follows:

[0075] The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３ , δ, ppm): 1.41 (quin, J=7.3Hz, 2H, -CHCH ２ CH ２ -), 1.66 (quin, J=6.4Hz, 2H, -CH ２ CH ２ O-), 2.00 (q, J=7.3Hz, 2H, CH ２ CHCH ２ -), 2.45 (s, 3H, CH ３ ), 4.03 (t, J=6.4Hz, 3H, -CH ２ O-), 4.93-4.99 (m, 2H, CH ２CH-), 5.67-5.77 (m, 1H, CH), 7.35 (d, J = 8.2Hz, 2H, Ar), 7.79 (d, J = 8.2Hz, 2H, Ar) １３ C-NMR (400MHz, CDCl ３ , δ, ppm): 21.45, 24.4, 28.0, 32.8, 70.3, 114.9, 127.7, 132.9, 137.8, 144.6 IR (KBr, ν): 1188, 1359, 1456, 1496, 1599, 2936

[0076] (Procedure 2) To a 200 mL recovery flask were added 12.7 g (50.0 mmol) of Hex-5-en-1-yl 4-methylbenzenesulfonate obtained in Procedure 1, 9.13 g (60.0 mmol) of methyl 4-hydroxybenzoate, 9.68 g (70.0 mmol) of potassium carbonate, a catalytic amount of potassium iodide, and 125 mL of acetone to obtain Solution C. Solution C was stirred at 70°C for 48 hours. After stirring, Solution C was filtered, and the solvent was evaporated under reduced pressure. 100 mL of water was added to the obtained solution and stirred, and then the organic layer was extracted with dichloromethane. The organic layer was washed with a 1 mol / L aqueous sodium hydroxide solution and saturated saline, in that order, and dried over magnesium sulfate. The solvent was then evaporated under reduced pressure to obtain 11.0 g of methyl 4-(hex-5-en-1-yloxy)benzoate. The yield was 94%. １ H-NMR (400MHz, CDCl ３ ), １３ C-NMR (400MHz, CDCl ３ The structure was confirmed by IR (KBr, v). The reaction formula for step 2 is as follows:

[0077] The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３ , δ, ppm): 1.54-1.62 (m, 2H, -CHCH ２ CH ２ -), 1.82 (quin, J=6.4Hz, 2H, -CH ２ CH ２O-), 2.14 (q, J=7.3Hz, 2H, CH ２ CHCH ２ -), 3.88 (s, 3H, CH ３ ), 4.01 (t, J=6.4Hz, 2H, -CH ２ O-), 4.97-5.07 (m, 2H, CH ２ CH-), 5.78-5.88 (m, 1H, CH), 6.90 (d, J = 9.2Hz, 2H, Ar), 7.98 (d, J = 8.7Hz, 2H, Ar) １３ C-NMR (400MHz, CDCl ３ , δ, ppm): 25.2, 28.5, 33.3, 51.8, 67.9, 114.0, 114.8, 122.3, 127.0, 131.5, 138.3, 162.8, 166.7 IR (KBr, ν): 912, 1105, 1168, 1254, 1392, 1471, 1501, 1606, 1640, 1718, 2948

[0078] (Procedure 3) 9.37 g (40.0 mmol) of methyl 4-(hex-5-en-1-yloxy)benzoate obtained in Procedure 2, 5.2 g (92.7 mmol) of potassium hydroxide, 200 mL of ethanol, and 32 mL of water were added to a 300 mL recovery flask to obtain Solution D. Solution D was stirred at 90°C for 7 hours. After stirring, Solution D was cooled to room temperature (25°C) and then added to 300 mL of 2 mol / L hydrochloric acid, and the precipitate was filtered off. Recrystallization with ethanol yielded 6.85 g of 4-(hex-5-en-1-yloxy)benzoic acid. The yield was 78%. Furthermore, the compound obtained was as follows: １ H-NMR (400MHz, CDCl ３ ), １３ C-NMR (400MHz, CDCl ３ The structure was confirmed by IR (KBr, v). The reaction formula for step 3 is as follows:

[0079] The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３, δ, ppm): 1.56-1.63 (m, 2H, -CHCH ２ CH ２ -), 1.84 (quin, J=6.4Hz, 2H, -CH ２ CH ２ O-), 2.15 (q, J = 7.3Hz, 2H, CH ２ CHCH ２ -), 4.04 (t, J = 6.4Hz, 2H, -CH ２ O-), 4.98-5.08 (m, 2H, CH ２ CH-), 5.79-5.89 (m, 1H, CH), 6.94 (d, J = 8.7Hz, 2H, Ar), 8.07 (d, J = 9.16Hz, 2H, Ar) １３ C-NMR (400MHz, CDCl ３ , δ, ppm): 25.2, 28.5, 33.3, 68.0, 114.1, 114.9, 121.4, 132.3, 138.3, 163.6, 172.3 IR (KBr, ν): 915, 1457, 1514, 1607, 1642, 1686, 2665, 2941

[0080] (Procedure 4) To a 200 mL recovery flask were added 6.61 g (30.0 mmol) of 4-(hex-5-en-1-yloxy)benzoic acid obtained in Procedure 3, 1.86 g (10.0 mmol) of 4,4'-dihydroxybiphenyl, 3.79 g (30.0 mmol) of N,N'-Diisopropylcarbodiimide (DIC), a catalytic amount of 4-dimethylaminopyridine, and 100 mL of tetrahydrofuran, and the mixture was stirred for 72 hours to obtain Reaction Solution E. Reaction Solution E was reprecipitated in methanol, and the precipitate was separated by filtration to obtain 5.76 g of [1,1'-biphenyl]-4,4'-diyl bis(4-(hex-5-en-1-yloxy)benzoate). The yield was 97%. １ H-NMR (400MHz, CDCl ３ ), and １３ C-NMR (400MHz, CDCl ３ The reaction formula for step 4 is as follows:

[0081] It's a nice little snack with a snowflake. １ FAMOUS(4000000000000000000000000000000). ３ ,δ,b:157164(y,40,DAN ２ 10 ２ 4,185(55,S64,40,DA ２ 10 ２ 8,215(1B,S600,40,0 ２ THIS IS THE ２ 6,406(9,D640,4000 ２ 8,49955008(I,40,0 ２ SH,589589(Y,20,0 ２ HEY,688(E),S820,408 THIS,728(E),S480,40,20 6,7600,4800,400,000 C,8170,087,40,000,000,000,000,000,000,000,000,0 １３ SHY(400000000000000000000000000000000). ３ ,δ,b00252,285,334, 681,1143,1149,1215 1221,1282,1323,1 ,1384,15005,1635,160

[0082] (Procedure 5) To a 100 mL recovery flask were added 3.54 g (6.00 mmol) of [1,1'-biphenyl]-4,4'-diyl bis(4-(hex-5-en-1-yloxy)benzoate) obtained in Procedure 4, 5.18 g (30.0 mmol) of 3-chlorobenzoic acid, and 20 mL of dichloromethane, and the mixture was stirred at 0°C for 3 hours. Then, 3.11 g (18.0 mmol) of 3-chlorobenzoic acid was added and the mixture was stirred at 0°C for an additional 3 hours to obtain reaction solution F. Reaction solution F was filtered, and the filtrate was washed with sodium thiosulfate. The mixture was then dried over magnesium sulfate, and the solvent was then distilled off under reduced pressure. Column chromatography on silica gel was carried out using dichloromethane, and recrystallization was carried out using toluene to obtain 2.55 g of [1,1'-biphenyl]-4,4'-diyl bis(4-(4-(oxiran-2-yl)butoxy)benzoate). The yield was 68%. The compound obtained was １ H-NMR (400MHz, CDCl ３ The reaction formula for step 5 is as follows:

[0083] The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３ , δ, ppm): 1.56-1.71 (m, 8H, epoxy CH ２ CH ２ -), 1.89 (quin, J=6.4Hz, 4H, -CH ２ CH ２ CO-), 2.49-2.51 (m, 2H, epoxy CH), 2.77 (t, J=4.6Hz, 2H, epoxy CH ２ ), 2.93-2.96 (m, 2H, epoxy CH ２ ), 4.06 (t, J = 6.41Hz, 4H, -CH ２ CO-), 6.97 (d, J = 8.7 Hz, 4H, -OArCO-), 7.27 (d, J = 8.7 Hz, 4H, -ArAr -), 7.62 (d, J = 8.7 Hz, 4H, -ArAr-), 8.16 (d, J = 9.2 Hz, 4H, -OArCO-)

[0084] (Curing agent) TPK4: a phenolic compound represented by the following structure TPK8: a phenolic compound represented by the following structure Novolac-based: a phenolic compound represented by the following structure, "TD-2106" manufactured by DIC Corporation TP4: A phenolic compound represented by the following structure: TP8: A phenolic compound represented by the following structure:

[0085] Of the above curing agents, TPK4 was obtained by the following Synthesis Example 2, TPK8 by the following Synthesis Example 3, TP4 by the following Synthesis Example 4, and TP8 by the following Synthesis Example 5. [Synthesis Example 2] (Procedure 1) 9.6 g (72 mmol) of aluminum chloride was added to a 200 mL two-necked recovery flask and dissolved in 73 mL of dichloromethane under an argon atmosphere to obtain reaction solution G. Reaction solution G was cooled to -10°C, and 9.1 g (66 mmol) of 1,2-dimethoxybenzene was added and stirred for 10 minutes. Thereafter, 5.5 g (30 mmol) of adipoyl chloride was added dropwise, and after stirring for 30 minutes, the mixture was heated to 0°C and stirred for 20 hours to obtain reaction solution H. Reaction solution H was quenched with 2 mol / L hydrochloric acid, and the organic layer was extracted with dichloromethane. The organic layer was washed with a 10 wt % potassium carbonate solution and saturated saline solution in that order, and then dried over magnesium sulfate. The dried organic layer was reprecipitated in hexane to obtain 10.8 g of 1,6-bis(3,4-dimethoxyphenyl)hexane-1,6-dione. The yield was 93%. The compound obtained was １ H-NMR (400MHz, CDCl ３ The structure was confirmed by the following reaction formula for step 1:

[0086] The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３ , δ, ppm): 1.84 (quin, J=2.0Hz, 4H, -CH ２-), 3.01 (t, J=6.8Hz, 4H, -COCH ２ -), 3.94 (s, 6H, -OCH ３ -), 3.96 (s, 6H, -OCH ３ -), 6.89 (d, J = 8.4Hz, 2H, Ar), 7.53 (s, 2H, Ar), 7.60 (d, J = 8.4Hz, 2H, Ar)

[0087] (Procedure 2) 0.07 g (0.5 mmol) of potassium carbonate and 1.9 g (5 mmol) of 1,6-bis(3,4-dimethoxyphenyl)hexane-1,6-dione obtained in Procedure 1 were added to a 100 mL two-necked recovery flask. Under a nitrogen atmosphere, 25 mL of N-methylpyrrolidineone (NMP) and 4.4 g (40 mmol) of benzenethiol were added, followed by stirring at 210°C for 3 hours. After cooling to room temperature (25°C), the reaction solution was reprecipitated in 1 mol / L hydrochloric acid. The precipitate was then dissolved in DMF, reprecipitated in diethyl ether, and purified by acid precipitation to obtain 1,6-bis(3,4-dihydroxyphenyl)hexane-1,6-dionen (TPK4). The yield was 57%. １ H-NMR (400MHz, CDCl ３ The structure was confirmed by the following reaction scheme in Step 2:

[0088] The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, DMSO-d ６ , δ, ppm): 1.61 (quin, J=3.2Hz, 4H, -CH ２ -), 2.89 (t, J=6.0Hz, 4H, -COCH ２ -), 6.80 (d, J = 7.9 Hz, 2H, Ar), 7.34 (s, 2H, Ar), 7.36 (d, J = 7.6 Hz, 2H, Ar). The melting point obtained by DSC measurement was 261°C.

[0089] Synthesis Example 3 (Procedure 1) 4.8 g (36 mmol) of aluminum chloride was added to a 100 mL two-necked recovery flask and dissolved in 39 mL of dichloromethane under an argon atmosphere to obtain reaction solution I. Reaction solution I was cooled to -10°C, and 4.6 g (33 mmol) of 1,2-dimethoxybenzene was added and stirred for 10 minutes. Thereafter, 3.6 g (15 mmol) of sebacoyl chloride was added dropwise, and after stirring for 30 minutes, the temperature was raised to 0°C and stirred for 20 hours to obtain reaction solution J. Reaction solution J was quenched with 2 mol / L hydrochloric acid, and the organic layer was extracted with dichloromethane. The organic layer was washed successively with 10 wt % potassium carbonate solution and saturated brine, and then dried over magnesium sulfate. The dried organic layer was reprecipitated in hexane to obtain 4.9 g of 1,10-bis(3,4-dimethoxyphenyl)decane-1,10-dione. The yield was 74%. １ H-NMR (400MHz, CDCl ３ The structure was confirmed by the following reaction formula for step 1:

[0090] The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３ , δ, ppm): 1.36 (m, 8H, -CH ２ -), 1.73 (quin, J=7.6Hz, 4H, -COCH ２ CH ２ -), 2.92 (t, J = 7.3Hz, 4H, -COCH ２ -), 3.94 (s, 6H, -OCH ３ -), 3.95 (s, 6H, -OCH ３ -), 6.89 (d, J = 7.9Hz, 2H, Ar), 7.53 (s, 2H, Ar), 7.59 (d, J = 8.4Hz, 2H, Ar)

[0091] (Procedure 2) 0.14 g (1.0 mmol) of potassium carbonate and 2.2 g (5 mmol) of 1,10-bis(3,4-dimethoxyphenyl)decane-1,10-dione obtained in Procedure 1 were added to a 100 mL two-necked recovery flask. Under a nitrogen atmosphere, 25 mL of N-methylpyrrolidineone (NMP) and 4.4 g (40 mmol) of benzenethiol were added, followed by stirring at 210°C for 3 hours. After cooling to room temperature (25°C), the reaction solution was reprecipitated in 1 mol / L hydrochloric acid. The precipitate was then dissolved in THF, reprecipitated in hexane, and purified by acid precipitation to obtain 1.7 g of 1,10-bis(3,4-dihydroxyphenyl)decane-1,10-dione (TPK8). The yield was 89%. １ H-NMR (400MHz, CDCl ３ The structure was confirmed by the following reaction scheme in Step 2:

[0092] The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３ , δ, ppm): 1.27 (m, 8H, -CH ２ -), 1.55 (quin, J=6.7Hz, 4H, -COCH ２ CH ２ -), 2.82 (t, J = 7.3Hz, 4H, -COCH ２ -), 6.76 (d, J = 7.9 Hz, 2H, Ar), 7.31 (s, 2H, Ar), 7.33 (d, J = 8.4 Hz, 2H, Ar). The melting point obtained by DSC measurement was 245°C.

[0093] Synthesis Example 4 (Procedure 1) 1.9 g (5 mmol) of 1,6-bis(3,4-dimethoxyphenyl)hexane-1,6-dione obtained in Procedure 1 of Synthesis Example 2 was added to a 50 mL recovery flask and dissolved in 25 mL of dichloromethane. Then, 0.20 g of 10% Pd / C catalyst was added, and the mixture was stirred for 18 hours at room temperature under a hydrogen atmosphere. The reaction solution was filtered through Celite, and the solvent in the obtained filtrate was evaporated under reduced pressure to obtain 1.5 g of the target compound, 1,6-bis(3,4-dimethoxyphenyl)hexane. The yield was 77%. Furthermore, the compound obtained was １ H-NMR (400MHz, CDCl ３ The structure was confirmed by the following reaction formula for step 1: The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３ , δ, ppm): 1.36 (quin, J = 3.7Hz, 4H, -CH ２ -), 1.60 (quin, J=6.8Hz, 4H, -ArCH ２ CH ２ -), 2.55 (t, J = 7.6Hz, 4H, -ArCH ２ -), 3.86 (s, 6H, -OCH ３ -), 3.87 (s, 6H, -OCH ３ -), 6.70 (s, 2H, Ar), 6.71 (d, J=8.4Hz, 2H, Ar), 6.78 (d, J=8.4Hz, 2H, Ar).

[0094] (Procedure 2) 0.14 g (1.0 mmol) of potassium carbonate and 0.72 g (2 mmol) of 1,6-bis(3,4-dimethoxyphenyl)hexane were added to a 30 mL two-necked recovery flask. Under a nitrogen atmosphere, 10 mL of N-methylpyrrolidineone (NMP) and 1.8 g (16 mmol) of benzenethiol were added, followed by stirring at 210°C for 8 hours. After cooling to room temperature, the reaction solution was added to saturated brine and extracted with THF. The organic layer was dried over magnesium sulfate and reprecipitated in hexane to obtain 0.38 g of the target compound, 4,4'-(hexane-1,6-diyl)bis(benzene-1,2-diol). The yield was 54%. Furthermore, the compound obtained was １ H-NMR (400MHz, CDCl ３ The structure was confirmed by the following reaction scheme in Step 2: The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３ , δ, ppm): 1.26 (quin, J = 3.7 Hz, 4H, -CH2-), 1.46 (quin, J = 6.8 Hz, 4H, -ArCH ２ CH ２ -), 2.36 (t, J = 7.6Hz, 4H, -ArCH ２ -), 6.39 (d, J = 7.6 Hz, 2H, Ar), 6.53 (s, 2H, Ar), 6.60 (d, J = 8.0 Hz, 2H, Ar). The melting point obtained by DSC measurement was 135°C.

[0095] Synthesis Example 5 (Procedure 1) 2.2 g (5 mmol) of 1,10-bis(3,4-dimethoxyphenyl)decane-1,10-dione obtained in Procedure 1 of Synthesis Example 3 was added to a 50 mL recovery flask and dissolved in 20 mL of dichloromethane. Then, 0.40 g of 10% Pd / C catalyst was added, and the mixture was stirred at room temperature under a hydrogen atmosphere for 36 hours. The reaction solution was filtered through Celite, and the solvent in the obtained filtrate was evaporated under reduced pressure to obtain 1.8 g of the target compound, 1,10-bis(3,4-dimethoxyphenyl)decane. The yield was 81%. Furthermore, the compound obtained was １ H-NMR (400MHz, CDCl ３ The structure was confirmed by the following reaction formula for step 1: The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３ , δ, ppm): 1.30 (m, 12H, -CH ２ -), 1.58 (quin, J=3.6Hz, 4H, -ArCH ２ CH ２ -), 2.54 (t, J = 7.6Hz, 4H, -ArCH ２ -), 3.86 (s, 6H, -OCH ３ -), 3.87 (s, 6H, -OCH ３ -), 6.70 (s, 2H, Ar), 6.72 (d, J = 5.6 Hz, 2H, Ar), 6.79 (d, J = 9.2 Hz, 2H, Ar).

[0096] (Procedure 2) 0.14 g (1.0 mmol) of potassium carbonate and 0.83 g (2 mmol) of 1,10-bis(3,4-dimethoxyphenyl)decane were added to a 30 mL two-necked recovery flask. Under a nitrogen atmosphere, 10 mL of N-methylpyrrolidineone (NMP) and 1.8 g (16 mmol) of benzenethiol were added, followed by stirring at 210°C for 8 hours. After cooling to room temperature, the reaction solution was added to saturated brine and extracted with THF. The organic layer was dried over magnesium sulfate and reprecipitated in hexane to obtain 0.52 g of the target compound, 4,4'-(decane-1,10-diyl)bis(benzene-1,2-diol). The yield was 73%. Furthermore, the compound obtained was １ H-NMR (400MHz, CDCl ３ The structure was confirmed by the following reaction scheme in Step 2: The peaks detected during structural confirmation are as follows: １ H-NMR (400MHz, CDCl ３ , δ, ppm): １ H-NMR (400MHz, DMSO-d ６ , δ, ppm): 1.23 (m, 12H, -CH ２ -), 1.46 (quin, J=6.0Hz, 4H, -ArCH ２ CH ２ -), 2.36 (t, J = 7.2Hz, 4H, -ArCH ２ -), 6.39 (d, J = 8.0 Hz, 2H, Ar), 6.53 (s, 2H, Ar), 6.60 (d, J = 8.0 Hz, 2H, Ar). The melting point obtained by DSC measurement was 133°C.

[0097] (Curing accelerator) Organic phosphine compound: "TPP" manufactured by Hokko Chemical Industry Co., Ltd. (Thermal conductive filler) Alumina: "AA-03" manufactured by Sumitomo Chemical Co., Ltd., average particle size 3.5 μm

[0098] [Example 1] A homogeneous epoxy resin composition was prepared by placing the components shown in Table 1 in an aluminum container placed on a hot plate maintained at 170°C and mixing with stirring. This epoxy resin composition was cured by heating in an oven at 200°C for 12 hours, to obtain a homogeneous cured epoxy resin product.

[0099] Examples 2 to 10, Comparative Examples 1 to 4 The same procedures as in Example 1 were carried out except that the composition of each component was changed as shown in Tables 1 to 4.

[0100]

[0101] As is clear from Table 1 above, when comparing the curable resin compositions prepared in Examples 1 and 2, which used epoxy resins having a mesogenic skeleton, with those prepared in Comparative Example 1, the curable resin compositions prepared in Examples 1 and 2 had relatively high thermal conductivity due to the use of a phenolic compound having a predetermined structure as a curing agent. In contrast, the curable resin composition prepared in Comparative Example 1 had relatively low thermal conductivity due to the use of a curing agent not having a predetermined structure.

[0102]

[0103] As is clear from Table 2 above, when comparing the curable resin compositions prepared in Examples 3 and 4, which used an epoxy resin having a biphenyl skeleton, and Comparative Example 2, the curable resin compositions prepared in Examples 3 and 4 had relatively high thermal conductivity due to the use of a phenolic compound having a predetermined structure as a curing agent. In contrast, the curable resin composition prepared in Comparative Example 2 had relatively low thermal conductivity due to the use of a curing agent not having a predetermined structure.

[0104]

[0105] As is clear from Table 3 above, when comparing the curable resin compositions prepared in Examples 5 and 6, which used bisphenol A as the epoxy resin, and Comparative Example 3, the curable resin compositions prepared in Examples 5 and 6 had relatively high thermal conductivity due to the use of a phenolic compound having a predetermined structure as the curing agent. In contrast, the curable resin composition prepared in Comparative Example 3 had relatively low thermal conductivity due to the use of a curing agent not having a predetermined structure. As is clear from Table 4 above, the curable resin compositions prepared in Examples 9 and 10, which contained a thermally conductive filler, had higher thermal conductivities than the curable resin compositions prepared in Examples 1 and 2, which did not contain a thermally conductive filler. In contrast, the curable resin composition prepared in Comparative Example 4 had lower thermal conductivities than the curable resin compositions prepared in Examples 9 and 10.

Claims

1. A curable resin composition comprising a curable resin and a phenolic compound, wherein the phenolic compound has a structure represented by the following formula (1): (X is a direct bond, -CH=CH-, -C≡C-, -C(=O)-, -C(=O)-O-, -C(=O)-NH-, -CH=N-, -CH=N-N=CH-, -N=N-, -N ＋ (-O － )=N-, -CH=C(CH ３ )-, -CH=C(CN)-, -CH=CH-C(=O)-, -Ph-C(=O)-, -Ph-, -Ph-Ph-, -S(=O) ２ -, -C(=O)OR Ａ -OC(=O)-, -OC(=O)-R Ａ -C(=O)-O-, -C(=O)O-Ph-O-C(=O)-, or -O-C(=O)-Ph-C(=O)-O-, where Ph represents an unsubstituted or substituted aromatic ring, Y represents a linear or branched alkylene chain having 1 to 20 carbon atoms, n represents an integer of 2 to 5, and R Ａ represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms.

2. The curable resin composition according to claim 1, further comprising a thermally conductive filler and an epoxy resin as the curable resin.

3. The curable resin composition according to claim 1 or 2, wherein the curable resin is an epoxy resin having a mesogenic skeleton.

4. A cured product of the curable resin composition according to claim 1 or 2.

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