WO2019159368A1 - Epoxy resin composition, epoxy resin cured product, heat conductive film, and method for producing epoxy resin cured product - Google Patents

Epoxy resin composition, epoxy resin cured product, heat conductive film, and method for producing epoxy resin cured product Download PDF

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Publication number
WO2019159368A1
WO2019159368A1 PCT/JP2018/005788 JP2018005788W WO2019159368A1 WO 2019159368 A1 WO2019159368 A1 WO 2019159368A1 JP 2018005788 W JP2018005788 W JP 2018005788W WO 2019159368 A1 WO2019159368 A1 WO 2019159368A1
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Prior art keywords
epoxy resin
resin composition
liquid crystal
crystal structure
epoxy
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PCT/JP2018/005788
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French (fr)
Japanese (ja)
Inventor
竹澤　由高
慎吾 田中
房郎 北條
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日立化成株式会社
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Priority to PCT/JP2018/005788 priority Critical patent/WO2019159368A1/en
Publication of WO2019159368A1 publication Critical patent/WO2019159368A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/02—Polycondensates containing more than one epoxy group per molecule
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
    • C08G59/62—Alcohols or phenols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins

Definitions

  • the present invention relates to an epoxy resin composition, an epoxy resin cured product, a heat conductive film, and a method for producing an epoxy resin cured product.
  • the amount of heat generated per unit volume tends to increase with the increase in energy density due to downsizing and higher performance of electronic devices. For this reason, high heat conductivity is calculated
  • the epoxy resin composition containing an epoxy resin is widely used for the insulating material from the viewpoint of high withstand voltage and easy molding.
  • the present invention provides an epoxy resin composition, an epoxy resin cured product, a thermally conductive film, and a method for producing an epoxy resin cured product that are excellent in thin film formability and thermal conductivity in a cured state. This is the issue.
  • a reaction-induced epoxy resin composition that includes an epoxy compound and a curing agent and is capable of forming a smectic liquid crystal structure, and does not contain a filler or the filler content is a non-volatile content of the epoxy resin composition.
  • the epoxy resin composition which is 20 mass% or less of the whole.
  • ⁇ 2> The epoxy resin composition according to ⁇ 1>, wherein the smectic liquid crystal structure forms a domain, and an average value of the diameter of the domain is 20 ⁇ m or more.
  • ⁇ 3> The epoxy resin composition according to ⁇ 1> or ⁇ 2>, wherein the smectic liquid crystal structure forms a domain, and the domain includes a spherulite.
  • ⁇ 4> The epoxy resin composition according to any one of ⁇ 1> to ⁇ 3>, wherein the smectic liquid crystal structure is formed via a nematic liquid crystal structure.
  • ⁇ 5> The epoxy resin composition according to any one of ⁇ 1> to ⁇ 4>, wherein the smectic liquid crystal structure can be formed at any curing temperature selected from the range of 130 ° C. to 160 ° C.
  • ⁇ 6> The epoxy resin composition according to any one of ⁇ 1> to ⁇ 5>, wherein a smectic liquid crystal structure can be formed within 3 minutes at a curing temperature of 160 ° C.
  • R 1 to R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
  • the filler includes at least one selected from the group consisting of silica particles, alumina particles, magnesium oxide particles, aluminum nitride particles, and boron nitride particles.
  • ⁇ 12> A cured epoxy resin, which is a cured product of the epoxy resin composition according to any one of ⁇ 1> to ⁇ 11>.
  • the cured epoxy resin according to ⁇ 12> having a periodic structure of a smectic liquid crystal structure, wherein the periodic length of the periodic structure is 1.0 nm to 4.0 nm.
  • ⁇ 14> A heat conductive film which is a film-like product of the cured epoxy resin according to ⁇ 12> or ⁇ 13>.
  • ⁇ 15> including a step of heat-treating the epoxy resin composition according to any one of ⁇ 1> to ⁇ 11>, wherein the heat treatment is performed at a temperature X (° C.) satisfying the following formula: Production method.
  • an epoxy resin composition an epoxy resin cured product, a thermally conductive film, and a method for producing an epoxy resin cured product that are excellent in thin film formability and thermal conductivity in a cured state.
  • the content of each component in the composition is the sum of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. It means the content rate of.
  • the particle diameter of each component in the composition is a mixture of the plurality of types of particles present in the composition unless there is a specific indication when there are a plurality of types of particles corresponding to each component in the composition. Means the value of.
  • the average thickness (also referred to as the average value of the thickness) is a value given as an arithmetic average value obtained by measuring the thickness of five randomly selected objects. The thickness can be measured using a micrometer or the like.
  • the epoxy resin composition of the present embodiment is a reaction-induced epoxy resin composition that includes an epoxy compound and a curing agent and can form a smectic liquid crystal structure, and does not contain a filler or the filler content is It is 20 mass% or less of the whole non volatile matter of an epoxy resin composition.
  • the epoxy resin composition of the present embodiment (hereinafter also simply referred to as an epoxy resin composition) does not contain a filler, or its content is 20% by mass or less of the entire nonvolatile content of the epoxy resin composition. The deterioration of the thin film formation property by containing is suppressed.
  • the epoxy resin composition is a reaction-induced type, it is considered that excellent fluidity before curing at a curing temperature is achieved and good thin film formability is achieved.
  • the epoxy resin composition of the present embodiment can form a smectic liquid crystal structure, it is considered that good thermal conductivity after curing is achieved.
  • the “reaction-inducing epoxy resin composition” is an isotropic structure (isotropic phase) in which the liquid crystal structure is not formed before the curing reaction starts, but the liquid crystal structure is developed with the progress of the curing reaction. It means an epoxy resin composition having the property of forming.
  • the epoxy resin composition that is not reaction-induced include a resin composition in which a liquid crystal structure is already formed before the curing reaction starts and the curing reaction proceeds in the state of the liquid crystal structure.
  • the epoxy resin composition has higher fluidity in the isotropic structure state than in the liquid crystal structure state. For this reason, reaction-induced epoxy resin compositions tend to have higher fluidity before curing at the curing temperature than non-reaction-induced epoxy resin compositions. Moreover, since the reaction-induced epoxy resin composition also forms a liquid crystal structure after curing in the same manner as the non-reaction-induced epoxy resin composition, high thermal conductivity can be obtained.
  • the epoxy resin composition is reaction-induced depends on the molecular structure of the epoxy compound and the molecular structure of the curing agent.
  • the epoxy resin composition of the present embodiment can form a smectic liquid crystal structure by a reaction between an epoxy compound and a curing agent.
  • An epoxy compound having a mesogenic structure is an example of an epoxy compound that can react with a curing agent to form a liquid crystal structure such as a smectic liquid crystal structure (hereinafter also referred to as a liquid crystalline epoxy compound).
  • the “epoxy compound having a mesogen structure” means a compound having an epoxy group and a mesogen structure.
  • mesogen structure examples include a biphenyl structure, a terphenyl structure, a terphenyl analog structure, an anthracene structure, a structure in which two or more of these mesogen structures are connected by an azomethine group or an ester group, a phenylbenzoate structure, a cyclohexylbenzoate structure, and the like. It is done.
  • the “resin matrix” means a portion corresponding to a reaction product of an epoxy compound and a cured product in a cured product of an epoxy resin composition (hereinafter also referred to as an epoxy resin cured product).
  • a higher order structure (periodic structure) formed in a resin matrix means a state in which molecules are aligned in a resin matrix (for example, a crystal structure or a liquid crystal structure is present in the resin matrix). Existing state).
  • the presence of such a crystal structure or liquid crystal structure can be directly confirmed by, for example, observation with a polarizing microscope under crossed Nicols or X-ray scattering.
  • the presence of the crystal structure or liquid crystal structure is indirectly measured by measuring the change in storage modulus of the resin with respect to temperature by utilizing the property that the change in the storage modulus of the resin with respect to temperature is reduced when the crystal structure or liquid crystal structure is present. Can be confirmed.
  • Examples of highly ordered higher order structures derived from mesogenic structures include nematic liquid crystal structures and smectic liquid crystal structures.
  • the nematic liquid crystal structure is a liquid crystal structure in which the molecular long axis is oriented in a uniform direction and has only alignment order.
  • the smectic liquid crystal structure is a liquid crystal structure having a one-dimensional positional order in addition to the alignment order and having a layer structure with a constant period. Further, the direction of the period of the layer structure is uniform within the same periodic structure of the smectic liquid crystal structure. That is, the order of the molecules is higher in the smectic liquid crystal structure than in the nematic liquid crystal structure.
  • a smectic liquid crystal structure when the epoxy compound reacts with the curing agent, a smectic liquid crystal structure is formed. Whether or not a smectic liquid crystal structure is formed by the reaction between the epoxy compound and the curing agent depends on the molecular structure of the epoxy compound, the molecular structure of the curing agent, the curing temperature, and the like. In the present embodiment, the entire periodic structure formed in the resin matrix may be a smectic liquid crystal structure or a part thereof may be a smectic liquid crystal structure.
  • the periodic structure formed in the resin matrix includes a smectic liquid crystal structure
  • X-ray diffraction measurement is performed using an X-ray analyzer (for example, manufactured by Rigaku Corporation) using a CuK ⁇ 1 line and a tube voltage of 40 kV, a tube current of 20 mA, and 2 ⁇ in the range of 0.5 ° to 30 °.
  • the ratio of the smectic liquid crystal structure in the entire periodic structure in the resin matrix is preferably 60% by volume or more, and more preferably 80% by volume or more.
  • the ratio of the smectic liquid crystal structure in the entire periodic structure can be easily measured by, for example, polishing the epoxy resin cured product to a predetermined thickness (for example, 50 ⁇ m) and observing with a polarizing microscope. Specifically, a cured epoxy resin having a smectic liquid crystal structure is polished to a thickness of 50 ⁇ m, and observed with a polarizing microscope (for example, product name: “OPTIPHOT2-POL” manufactured by Nikon Corporation) to produce a smectic liquid crystal.
  • a polarizing microscope for example, product name: “OPTIPHOT2-POL” manufactured by Nikon Corporation
  • the periodic structure of the smectic liquid crystal structure preferably has a period length (length of one period) of 1.0 nm or more, and more preferably 2.0 nm or more. When the period length is 1.0 nm or more, higher thermal conductivity can be exhibited.
  • the period length may be 4.0 nm, and is preferably 1.0 nm to 4.0 nm.
  • the periodic length of the periodic structure is obtained by performing X-ray diffraction using a cured epoxy resin product as a measurement sample under the above measurement conditions using a wide-angle X-ray diffractometer (for example, Rigaku Corporation, product name: “RINT2500HL”).
  • the diffraction angle thus obtained can be obtained by converting the following Bragg equation.
  • d is the length of one period
  • ⁇ is the diffraction angle
  • n is the reflection order
  • ⁇ is the X-ray wavelength (0.15406 nm).
  • the process in which the epoxy resin composition forms a smectic liquid crystal structure is not particularly limited. From the viewpoint of suppressing rapid volume shrinkage, it is preferable to form a smectic liquid crystal structure via a nematic liquid crystal structure. This is because when the transition from the isotropic structure to the smectic liquid crystal structure directly without passing through the nematic liquid crystal structure, the density change is large, and thus volume shrinkage tends to occur rapidly.
  • the smectic liquid crystal structure formed by the epoxy resin composition forms a domain
  • the average value of the domain diameter is preferably 20 ⁇ m or more, more preferably 40 ⁇ m or more. More preferably, it is 60 ⁇ m or more. From the viewpoint of isotropic property, the average value of the domain diameters is preferably 100 ⁇ m or less.
  • the “domain” corresponds to a portion in which a periodic structure is formed in one direction in the resin matrix, and the periodic structure is in a direction different from the portion where the periodic structure is not formed or the periodic structure of the domain. It means an island-like region surrounded by the formed part.
  • the diameter of the domain and its average value can be measured in a pseudo manner as the diameter of the cross section of the domain appearing in the observed cross section of the cured epoxy resin and its average value.
  • the diameter of the cross section of the domain is measured, for example, by polarizing microscope observation of the cured epoxy resin as described above.
  • the average value of the diameter of the cross section of the domain is measured for 10 randomly selected domains among the domains appearing in the observed cross section of the epoxy resin cured product, and the arithmetic average value is calculated as the domain of the smectic liquid crystal structure.
  • the diameter of a domain means the maximum diameter of a domain when the shape of the domain is not a perfect circle (ellipse, polygon, etc.).
  • the maximum diameter is the length of the longest line segment connecting the two arbitrary points located on the contour line of the domain appearing on the observation cross section of the cured epoxy resin.
  • the diameter of the domain can be controlled by, for example, the curing conditions of the epoxy resin composition.
  • the lower the curing temperature of the epoxy resin composition the slower the growth rate of the domains, with the result that the domain diameter tends to increase.
  • the longer the curing time of the epoxy resin composition the more the domain grows and the diameter tends to increase.
  • the curing temperature of the epoxy resin composition is preferably 160 ° C. or lower, more preferably 150 ° C. or lower, and further preferably 140 ° C. or lower. Further, the curing time of the epoxy resin composition is preferably 30 seconds or longer, and more preferably 1 minute or longer.
  • the curing temperature of the epoxy resin composition is preferably not too low. Accordingly, the curing temperature is preferably 130 ° C. or higher. Moreover, from the viewpoint of shortening the curing time of the epoxy resin composition, the curing time is preferably within 5 minutes, and more preferably within 3 minutes.
  • the epoxy resin composition is capable of forming a smectic liquid crystal structure at any curing temperature selected from the range of 130 ° C to 160 ° C. If a curing temperature range of 130 ° C. to 160 ° C. is passed, a smectic liquid crystal structure can be formed even if the curing temperature is not constant. For example, a smectic liquid crystal structure can be formed even in the process of raising the temperature from 30 ° C. to 180 ° C. at 5 ° C./min. In one embodiment, the epoxy resin composition is capable of forming a smectic liquid crystal structure within 3 minutes at a curing temperature of 160 ° C.
  • the smectic liquid crystal structure formed by the epoxy resin composition is in a domain state and preferably contains spherulites.
  • the spherulite means a domain whose three-dimensional shape is a sphere, an ellipsoid, or a disk. Whether the domain of the smectic liquid crystal structure contains spherulites can be determined, for example, by determining whether the shape of the domain appearing in the observed cross section of the cured epoxy resin is circular, elliptical, or the like.
  • each domain is grown without being deformed by an adjacent domain.
  • the method of making the epoxy resin composition before hardening contain a solvent is mentioned.
  • the domains collide with each other in the process of growing the domain of the smectic liquid crystal structure with hardening.
  • the individual domains tend not to be spherulites but to have a polygonal cross section.
  • the epoxy resin composition before curing contains a solvent and is cured while volatilizing the solvent, the epoxy resin composition is diluted with the solvent, so that the interval between the nuclei forming the smectic liquid crystal structure is widened.
  • the domains of the smectic liquid crystal structure do not collide with each other and the individual domains tend to be spherulites.
  • epoxy compound is not particularly limited as long as it can form a smectic liquid crystal structure by reacting with a curing agent, and may be one type or two or more types.
  • the epoxy compound preferably includes a compound represented by the following general formula (I) as an epoxy compound having a mesogenic structure. 1 type or 2 types or more may be sufficient as the compound represented by general formula (I).
  • R 1 to R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
  • R 1 to R 4 are each independently preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom.
  • 2 to 4 of R 1 to R 4 are hydrogen atoms, more preferably 3 or 4 are hydrogen atoms, and more preferably that all 4 are hydrogen atoms.
  • any of R 1 to R 4 is an alkyl group having 1 to 3 carbon atoms
  • at least one of R 1 and R 4 is preferably an alkyl group having 1 to 3 carbon atoms.
  • At least a part of the epoxy compound may be in a prepolymer state obtained by reacting with a curing agent (prepolymerizing agent) described later.
  • a curing agent prepolymerizing agent
  • an epoxy compound having a mesogen structure in the molecule including the compound represented by the general formula (I) is easily crystallized, and its solubility in a solvent is often lower than that of other epoxy resin compounds.
  • crystallization is suppressed and the moldability of the epoxy resin composition tends to be improved.
  • the prepolymerizing agent may be the same as or different from the curing agent described later.
  • the prepolymerizing agent is preferably a compound (divalent phenol compound) having two hydroxyl groups as substituents on one benzene ring.
  • the dihydric phenol compound include catechol, resorcinol, hydroquinone, and derivatives thereof.
  • the derivative of the divalent phenol compound include compounds in which an alkyl group having 1 to 8 carbon atoms is substituted on the benzene ring.
  • dihydric phenol compounds it is preferable to use at least one selected from the group consisting of resorcinol and hydroquinone from the viewpoint of improving the thermal conductivity of the cured product, and it is more preferable to use hydroquinone. Since hydroquinone has a structure in which two hydroxyl groups are substituted so as to have a para-position, a prepolymer obtained by reacting with an epoxy compound tends to have a linear structure. For this reason, it is considered that the stacking property of molecules is high and higher-order structures are more easily formed.
  • the prepolymerizing agent used for prepolymerization may be one kind or two or more kinds.
  • the blending ratio of the epoxy compound and the prepolymerizing agent is not particularly limited, and can be selected according to a desired molecular weight, a ratio to the whole epoxy compound, and the like.
  • the mixing ratio of the epoxy compound and the prepolymerizing agent is preferably the equivalent ratio of the epoxy group in the epoxy compound to the hydroxyl group in the prepolymerizing agent (epoxy group / hydroxyl group).
  • the blending ratio is preferably in the range of ⁇ 100 / 25, more preferably 100/10 to 100/15.
  • the content of the epoxy compound is preferably 5% by volume to 40% by volume and preferably 10% by volume to 35% by volume in the total nonvolatile content of the epoxy resin composition from the viewpoint of moldability and adhesiveness. More preferably, it is 15 volume% to 35 volume%, further preferably 15 volume% to 30 volume%.
  • the volume-based content of the epoxy compound with respect to the total nonvolatile content of the epoxy resin composition is a value determined by the following formula.
  • Content (% by volume) of epoxy compound with respect to the total nonvolatile content ⁇ (Bw / Bd) / ((Aw / Ad) + (Bw / Bd) + (Cw / Cd) + (Dw / Dd)) ⁇ ⁇ 100
  • each variable is as follows.
  • Aw Mass composition ratio of filler (% by mass) Bw: mass composition ratio of epoxy compound (mass%) Cw: mass composition ratio (% by mass) of curing agent Dw: mass composition ratio (% by mass) of other optional components (excluding solvent) Ad: Specific gravity of filler Bd: Specific gravity of epoxy compound Cd: Specific gravity of curing agent Dd: Specific gravity of other optional components (excluding solvent)
  • the epoxy compound contained in the epoxy resin composition may be a combination of a liquid crystal epoxy compound and another epoxy compound other than the liquid crystal epoxy compound.
  • Other epoxy compounds include glycidyl ethers of phenolic compounds such as bisphenol A, bisphenol F, bisphenol S, phenol novolak, cresol novolak, resorcinol novolak; glycidyl ethers of alcohol compounds such as butanediol, polyethylene glycol, and polypropylene glycol; phthalic acid Glycidyl esters of carboxylic acid compounds such as isophthalic acid and tetrahydrophthalic acid; glycidyl type (including methyl glycidyl type) epoxy compounds such as those in which active hydrogen bonded to a nitrogen atom such as aniline or isocyanuric acid is substituted with a glycidyl group; Vinylcyclohexene epoxide obtained by epoxidation of olefin bond in the molecule, 3,4-
  • the content of other epoxy compounds is not particularly limited, and is preferably 0.3 or less, more preferably 0.2 or less when the liquid crystalline epoxy compound is 1 on a mass basis, 0 More preferably, it is 1 or less.
  • the epoxy resin composition contains a curing agent.
  • the curing agent is not particularly limited as long as it is a compound capable of causing a curing reaction with the epoxy compound.
  • Specific examples of the curing agent include amine curing agents, acid anhydride curing agents, phenol curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, and blocked isocyanate curing agents. Only one type or two or more types of curing agents may be used.
  • the curing agent is preferably an amine curing agent or a phenol curing agent, more preferably a phenol curing agent, and a phenol curing agent containing a phenol novolac resin. Is more preferable.
  • low molecular phenol compounds and phenol resins obtained by novolacizing them can be used.
  • Low molecular phenol compounds include monofunctional phenol compounds such as phenol, o-cresol, m-cresol, and p-cresol, bifunctional phenol compounds such as catechol, resorcinol, hydroquinone, 1,2,3-trihydroxybenzene, 1 Trifunctional phenol compounds such as 1,2,4-trihydroxybenzene and 1,3,5-trihydroxybenzene can be used.
  • a phenol novolac resin obtained by connecting these low molecular phenol compounds with a methylene chain or the like to form a novolac can be used as a curing agent.
  • the phenol novolac resin used as the curing agent may contain a phenol compound as a monomer.
  • the monomer content ratio in the phenol novolac resin (hereinafter also referred to as “monomer content ratio”) is not particularly limited. From the viewpoint of thermal conductivity and moldability, the monomer content is preferably 5% by mass to 80% by mass, more preferably 15% by mass to 60% by mass, and 20% by mass to 50% by mass. More preferably it is.
  • the monomer content is 80% by mass or less, the amount of monomer that does not contribute to crosslinking during the curing reaction is suppressed, and the amount of the high-molecular-weight polymer that is crosslinked increases, so that a higher-density higher-order structure is formed, There is a tendency for conductivity to improve. Further, when the monomer content ratio is 5% by mass or more, it is easy to flow at the time of molding. Therefore, when the epoxy resin composition contains an inorganic filler, the adhesion with the filler is further improved and more excellent. Thermal conductivity and heat resistance tend to be achieved.
  • the number of equivalents of the functional group of the curing agent is preferably 0.005 to 5 equivalents, more preferably 0.01 to 3 equivalents with respect to 1 equivalent of the epoxy group in the epoxy compound.
  • the amount is preferably 0.5 equivalent to 1.5 equivalent. It exists in the tendency which can improve the hardening rate of an epoxy compound more as the equivalent number of the functional group of a hardening
  • curing agent is 0.005 equivalent or more with respect to 1 equivalent of an epoxy group. Moreover, it exists in the tendency which can control hardening reaction more appropriately that the equivalent number of the functional group of a hardening
  • the chemical equivalent in this specification represents the equivalent number of the hydroxyl group of the phenol curing agent with respect to 1 equivalent of an epoxy group, for example, when a phenol curing agent is used as a curing agent, and an amine curing agent is used as the curing agent. When used, it represents the number of equivalents of active hydrogen in the amine curing agent relative to 1 equivalent of epoxy group.
  • a curing accelerator may be used in combination as necessary.
  • the epoxy resin composition can be further sufficiently cured.
  • the kind in particular of hardening accelerator is not restrict
  • the curing accelerator include imidazole compounds, phosphine compounds, and borate salt compounds.
  • the epoxy resin composition may contain a filler.
  • ceramic particles can be used from the viewpoints of thermal conductivity and insulation. Examples of the ceramic particles include alumina particles, silica particles, magnesium oxide particles, boron nitride particles, aluminum nitride particles, and silicon nitride particles.
  • the filler preferably includes at least one selected from the group consisting of alumina particles, boron nitride particles, aluminum nitride particles, and magnesium oxide particles, and more preferably includes alumina particles.
  • the alumina particles preferably include alumina particles with high crystallinity, and more preferably include ⁇ -alumina particles.
  • a periodic structure of a smectic liquid crystal structure is formed in a direction perpendicular to the surface of the alumina particles from the viewpoint of thermal conductivity. Whether or not the periodic structure of the smectic liquid crystal structure is formed in the direction perpendicular to the surface of the alumina particles can be confirmed by, for example, observation of the cured epoxy resin as described above with a polarizing microscope.
  • the volume average particle diameter of the filler is preferably 0.01 ⁇ m to 1 mm from the viewpoint of thermal conductivity, and more preferably 0.10 ⁇ m to 100 ⁇ m from the viewpoint of filling properties.
  • the volume average particle diameter of the filler is measured using a laser diffraction method.
  • the measurement by the laser diffraction method can be performed using a laser diffraction scattering particle size distribution measuring device (for example, LS230 manufactured by Beckman Coulter, Inc.).
  • a laser diffraction scattering particle size distribution measuring device for example, LS230 manufactured by Beckman Coulter, Inc.
  • the particle diameter (D50) at which the cumulative volume from the small diameter side is 50% is defined as the volume average particle diameter of the filler.
  • the volume average particle diameter of the filler contained in the epoxy resin composition is measured using a laser diffraction / scattering particle size distribution analyzer after extracting the filler from the epoxy resin composition.
  • the extraction of the filler and the measurement of the volume average particle diameter can be performed by, for example, sufficiently dispersing the components other than the filler of the epoxy resin composition using an organic solvent, nitric acid, aqua regia, etc. with an ultrasonic disperser or the like.
  • a dispersion can be prepared by using the dispersion.
  • the extraction of the filler contained in the cured epoxy resin or the heat conductive film and the measurement of the volume average particle diameter can be performed in the same manner.
  • the content is 20% by mass or less of the entire nonvolatile content of the epoxy resin composition, preferably 15% by mass or less, and more preferably 10% by mass or less. preferable.
  • the epoxy resin composition contains a filler in an amount of a certain ratio or less, hardness, flexibility, fluidity, etc. can be easily adjusted, and the growth of a smectic liquid crystal structure is promoted by using the filler as a nucleus. The effect can be expected.
  • the filler content is 20% by mass or less of the entire nonvolatile content of the epoxy resin composition
  • the thin film formability of the epoxy resin composition is favorably maintained.
  • cures in the state which contacted the other member and the epoxy resin composition it exists in the tendency for the adhesiveness to another member to be fully acquired.
  • the domains in the smectic liquid crystal structure formed by the curing reaction are less likely to collide with the filler and tend to grow sufficiently to obtain high thermal conductivity.
  • the epoxy resin composition may further contain other components such as a solvent, a coupling agent, a dispersant, an elastomer, and a release agent. From the viewpoint of forming spherulite domains, the epoxy resin composition preferably contains a solvent.
  • the type of solvent is not particularly limited, and acetone, isobutyl alcohol, isopropyl alcohol, isopentyl alcohol, diethyl ether, ethylene glycol monoethyl ether, xylene, cresol, chlorobenzene, isobutyl acetate, isopropyl acetate, isopentyl acetate, ethyl acetate, methyl acetate , Cyclohexanol, cyclohexanone, 1,4-dioxane, dichloromethane, styrene, tetrachloroethylene, tetrahydrofuran, toluene, n-hexane, 1-butanol, 2-butanol, methanol, methyl isobutyl ketone, methyl ethyl ketone, methyl cyclohexanol, methyl cyclohexanone, chloroform , Carbon tetrachloride
  • the epoxy resin composition of the present embodiment has a high orientation of the epoxy compound and is excellent in thermal conductivity when used as a cured product. Therefore, the epoxy resin composition of the present embodiment is suitably used for a member (for example, a heat dissipation material) of a heat-generating electronic component (for example, an IC (Integrated Circuit) chip or a printed wiring board) of various electric and electronic devices. be able to.
  • a member for example, a heat dissipation material
  • a heat-generating electronic component for example, an IC (Integrated Circuit) chip or a printed wiring board
  • the manufacturing method of the cured epoxy resin of the present embodiment includes a step of heat-treating the epoxy resin composition of the present embodiment, and the heat treatment is performed at a temperature X (° C.) that satisfies the following formula. (B + 5 °C) ⁇ X ⁇ (A-5 °C)
  • A is the upper limit (° C.) of the temperature at which the epoxy resin composition can form a smectic liquid crystal structure
  • B is the lower limit (° C.) of the temperature at which the epoxy resin composition can form a smectic liquid crystal structure. It is. A and B satisfy the relationship B ⁇ A-10.
  • the temperature X of the heat treatment can be set according to the type and composition ratio of components contained in the epoxy resin composition. For example, it is preferably selected from the range of 100 ° C. to 200 ° C., more preferably selected from the range of 120 ° C. to 180 ° C.
  • the temperature X of the heat treatment may be constant from the start to the end of the heat treatment or may change. When X changes, it is preferable to satisfy the above conditions in the initial curing stage. Moreover, it is preferable that X satisfies the above-mentioned conditions at 20% or more of the total heat treatment time.
  • the time for the heat treatment is not particularly limited, and is preferably selected from a range of 5 minutes to 60 minutes, for example, and more preferably selected from a range of 10 minutes to 30 minutes.
  • the epoxy resin cured product obtained after the heat treatment may be further subjected to another heat treatment (hereinafter also referred to as “post-curing treatment”).
  • post-curing treatment By performing post-curing treatment on the cured epoxy resin, the crosslinking density tends to increase.
  • the post-curing treatment may be performed only once or twice or more.
  • the temperature of the post-curing treatment is not particularly limited, and is preferably selected from the range of 140 ° C. to 240 ° C., for example, and more preferably selected from the range of 160 ° C. to 220 ° C.
  • the temperature of the post-curing treatment may be constant from the start to the end of the heat treatment or may vary.
  • the time for the post-curing treatment is not particularly limited, and is preferably selected from a range of, for example, 10 minutes to 600 minutes, and more preferably selected from a range of 60 minutes to 300 minutes.
  • the heating device used for post-curing is not particularly limited, and a commonly used heating device can be used.
  • the epoxy resin composition may be heat-treated in a film state.
  • the heat conductive film of this embodiment which is a film-form material of an epoxy resin hardened
  • the cured epoxy resin of the present embodiment is a cured product of the epoxy resin composition of the present embodiment.
  • the heat conductive film of this embodiment is a film-like product of the cured epoxy resin of this embodiment.
  • the cured epoxy resin and the heat conductive film of the present embodiment are obtained by curing the epoxy resin composition of the present embodiment, the thin film formability is excellent and the heat conductivity is excellent.
  • a periodic structure having a smectic liquid crystal structure is formed.
  • the periodic length of the periodic structure of the smectic liquid crystal structure is preferably 2.0 nm to 4.0 nm, and more preferably 2.0 nm to 3.0 nm.
  • the heat conductive film is preferably prepared by performing a heat treatment in a state where the epoxy resin composition is formed into a film shape.
  • the average thickness of the heat conductive film is not particularly limited, and can be selected from a range of 0.01 mm to 3 mm, for example.
  • phenol novolak resin solution (hereinafter also referred to as curing agent 1).
  • the number average molecular weight of the obtained phenol novolak resin was 484, and the number of structural units n was 3.9 on average.
  • the monomer content ratio was 40% by mass. From 1 H-NMR measurement, it was found that an average of 2.1 hydroxyl groups were contained per structural unit of phenol novolac resin (corresponding to 1 molecule of phenol compound). The hydroxyl equivalent was 62 g / eq.
  • Epoxy compound 2, curing agent 1, and triphenylphosphine as a curing accelerator were mixed to prepare an epoxy resin composition.
  • curing agent 1 was adjusted so that ratio of the equivalent number of the hydroxyl group of the hardening
  • the compounding amount of the curing accelerator was set to 0.8% by mass with respect to the total mass of the epoxy compound 2 and the curing agent.
  • the state of the phase change accompanying the curing reaction during the heat treatment was examined by taking out the epoxy resin composition a plurality of times during the heat treatment and observing with a polarizing microscope. As a result, the structure changed in the order of isotropic structure (Iso), nematic liquid crystal structure (N), and smectic liquid crystal structure (Sm).
  • Iso isotropic structure
  • N nematic liquid crystal structure
  • Sm smectic liquid crystal structure
  • the measured diffraction angle 2 ⁇ was 3.2 °, and it was confirmed that a periodic structure of a smectic liquid crystal structure was formed. Moreover, the period length obtained by converting the measured diffraction angle by the Bragg equation was 2.7 (nm).
  • thermal conductivity The produced thermal conductive film was cut into a 1 cm square and used as a test piece for measuring thermal diffusivity.
  • the thermal diffusivity of the test piece was measured using a flash method apparatus (“NanoFlash LFA447” manufactured by NETZSCH). By multiplying the measurement result by the density measured by the Archimedes method and the specific heat measured by the DSC method, the thermal conductivity in the thickness direction of the heat conductive film was obtained and found to be 0.8 W / (m ⁇ K). It was.
  • Example 2 (Examples 2 and 3)
  • alumina particles manufactured by Nippon Steel & Sumikin Materials Co., Ltd., Micron Company, trade name: “AX3-32”, volume average particle size: 4 ⁇ m, the same in the following Examples and Comparative Examples) were used as epoxy resin compositions.
  • An epoxy resin composition was prepared in the same manner as in Example 1 except that the content was 5% by mass and 10% by mass with respect to the whole nonvolatile content, and a heat conductive film was produced.
  • the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • Example 4 In Example 1, an epoxy resin composition was prepared in the same manner as in Example 1 except that the epoxy compound 1 was used instead of the epoxy compound 2, and a heat conductive film was produced. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • the blending amount of the epoxy compound 1 and the curing agent 1 was adjusted so that the ratio of the number of equivalents of the hydroxyl group of the curing agent 1 to the number of equivalents of the epoxy group of the epoxy compound 1 (epoxy group: hydroxyl group) was 1: 1.
  • the blending amount of the curing accelerator was set to 0.8% by mass with respect to the total mass of the epoxy compound 1 and the curing agent 1.
  • Example 4 the epoxy resin composition was prepared in the same manner as in Example 4 except that the alumina particles were blended so that the content of the epoxy resin composition was 5% by mass and 10% by mass, respectively, with respect to the entire nonvolatile content.
  • Example 1 To prepare a heat conductive film.
  • the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • Example 7 In Example 1, instead of the epoxy compound 2, an epoxy compound having a mesogenic structure (1- (3-methyl-4-oxiranimethoxyphenyl) -4- (oxiranylmethoxyphenyl) -1-cyclohexene) (hereinafter referred to as “epoxy compound 2”)
  • epoxy compound 2 an epoxy compound having a mesogenic structure (1- (3-methyl-4-oxiranimethoxyphenyl) -4- (oxiranylmethoxyphenyl) -1-cyclohexene)
  • epoxy compound 2 an epoxy compound having a mesogenic structure (1- (3-methyl-4-oxiranimethoxyphenyl) -4- (oxiranylmethoxyphenyl) -1-cyclohexene)
  • the compounding amount of the epoxy compound 3 and the curing agent 1 was adjusted such that the ratio of the number of equivalents of the hydroxyl group of the curing agent 1 to the number of equivalents of the epoxy group of the epoxy compound 3 (epoxy group: hydroxyl group) was 1: 1.
  • the blending amount of the curing accelerator was set to 0.8% by mass with respect to the total mass of the epoxy compound 3 and the curing agent 1.
  • Example 7 the epoxy resin composition was the same as Example 7 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5% by mass and 10% by mass, respectively.
  • Example 7 To prepare a heat conductive film.
  • the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • Example 10 In Example 7, instead of curing agent 1, 1,5-diaminonaphthalene (hereinafter also referred to as curing agent 2) was used, and in the same manner as in Example 7, except that the curing accelerator was omitted.
  • An epoxy resin composition was prepared to produce a heat conductive film.
  • the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • the blending amount of the epoxy compound 3 and the curing agent 2 is adjusted so that the ratio of the number of equivalents of the amino group of the curing agent 2 to the number of equivalents of the epoxy group of the epoxy compound 3 (epoxy group: amino group) is 1: 1. did.
  • Example 10 the epoxy resin composition was the same as Example 10 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5 mass% and 10 mass%, respectively.
  • Example 10 To prepare a heat conductive film.
  • the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • Example 13 In Example 1, 5 g of methyl ethyl ketone (MEK) was further added as a solvent to prepare an epoxy resin composition. The prepared epoxy resin composition was stirred for 30 minutes at room temperature (25 ° C.) using a mix roller. Thereafter, it was formed into a film at room temperature. Next, heat treatment was performed at 140 ° C. for 30 minutes to produce a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • MEK methyl ethyl ketone
  • Example 13 the epoxy resin composition was prepared in the same manner as in Example 13 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5 mass% and 10 mass%, respectively.
  • Example 13 To prepare a heat conductive film.
  • the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • Example 1 In Example 1, in place of the epoxy compound 1, a bisphenol A type epoxy compound (trade name: “jER828”, hereinafter also referred to as “epoxy compound 4” manufactured by Mitsubishi Chemical Corporation), which is an epoxy compound having no mesogen structure, is used. Except having used, it carried out similarly to Example 1, and prepared the epoxy resin composition, and produced the heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • jER828 bisphenol A type epoxy compound manufactured by Mitsubishi Chemical Corporation
  • the compounding amount of the epoxy compound 4 and the curing agent 1 was adjusted so that the ratio of the number of equivalents of the hydroxyl group of the curing agent 1 to the number of equivalents of the epoxy group of the epoxy compound 4 (epoxy group: hydroxyl group) was 1: 1.
  • the blending amount of the curing accelerator was set to 0.8% by mass with respect to the total mass of the epoxy compound 4 and the curing agent 1.
  • Comparative Examples 2 and 3 the epoxy resin composition was prepared in the same manner as in Comparative Example 1 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5 mass% and 10 mass%, respectively.
  • a heat conductive film To prepare a heat conductive film.
  • the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • Example 10 an epoxy resin composition was prepared in the same manner as in Example 1 except that the epoxy compound 4 was used instead of the epoxy compound 3, and a heat conductive film was produced. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • the compounding amount of the epoxy compound 4 and the curing agent 2 is adjusted so that the ratio of the number of equivalents of the amino group of the curing agent 2 to the number of equivalents of the epoxy group of the epoxy compound 4 (epoxy group: amino group) is 1: 1. did.
  • Comparative Examples 5 and 6 the epoxy resin composition was the same as Comparative Example 4 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5 mass% and 10 mass%, respectively.
  • a heat conductive film To prepare a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • Example 7 an epoxy resin composition was prepared in the same manner as in Example 13 except that the epoxy compound 4 was used instead of the epoxy compound 2, and a heat conductive film was produced. Then, in the same manner as in Example 1, the periodic length, domain diameter, and thermal conductivity of the periodic structure were obtained. The results are shown in Table 1.
  • the compounding amount of the epoxy compound 4 and the curing agent 1 was adjusted so that the ratio of the number of equivalents of the hydroxyl group of the curing agent 1 to the number of equivalents of the epoxy group of the epoxy compound 4 (epoxy group: hydroxyl group) was 1: 1.
  • the blending amount of the curing accelerator was set to 0.8% by mass with respect to the total mass of the epoxy compound 4 and the curing agent 1.
  • Comparative Examples 8 and 9 In Comparative Example 7, the epoxy resin composition was the same as Comparative Example 7 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5% by mass and 10% by mass, respectively.
  • Example 10 (Comparative Example 10)
  • an epoxy resin composition was prepared in the same manner as in Example 1 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 50% by mass.
  • a conductive film was prepared.
  • the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
  • the thermal conductivity films produced in Comparative Examples 1 to 9 had lower thermal conductivity than the thermal conduction films produced in Examples. This is because the smectic liquid crystal domain is formed in the heat conduction film produced in the example, whereas the smectic liquid crystal structure domain is not formed in the heat conduction film produced in the comparative example. It is done.
  • the heat conductive film produced in Comparative Example 10 in which the content of alumina particles exceeded 20 mass% had smectic liquid crystal structure domains formed, but the domain diameter was smaller than those in Examples 1-15. This is presumably because the rate at which the domain growth collides with the alumina particles and stops is larger than in the example. Moreover, a heat conductive film having an average thickness of 50 ⁇ m could not be formed.

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Abstract

An epoxy resin composition that is a reaction induction-type epoxy resin composition containing an epoxy compound and a curing agent and capable of forming a smectic liquid crystal structure, that contains no filler or has a filler content of 20 mass% or less of the entire nonvolatile fraction of the epoxy resin composition.

Description

エポキシ樹脂組成物、エポキシ樹脂硬化物、熱伝導フィルム、及びエポキシ樹脂硬化物の製造方法Epoxy resin composition, cured epoxy resin, thermally conductive film, and method for producing cured epoxy resin
　本発明は、エポキシ樹脂組成物、エポキシ樹脂硬化物、熱伝導フィルム、及びエポキシ樹脂硬化物の製造方法に関する。 The present invention relates to an epoxy resin composition, an epoxy resin cured product, a heat conductive film, and a method for producing an epoxy resin cured product.
　近年、電子機器の小型化及び高性能化によるエネルギー密度の増加に伴い、単位体積当たりの発熱量が増大する傾向にある。このため、電子機器を構成する絶縁材料には高い熱伝導性が求められている。また、絶縁材料には、絶縁耐圧の高さ及び成形の容易さの観点から、エポキシ樹脂を含むエポキシ樹脂組成物が広く用いられている。 In recent years, the amount of heat generated per unit volume tends to increase with the increase in energy density due to downsizing and higher performance of electronic devices. For this reason, high heat conductivity is calculated | required by the insulating material which comprises an electronic device. Moreover, the epoxy resin composition containing an epoxy resin is widely used for the insulating material from the viewpoint of high withstand voltage and easy molding.
　エポキシ樹脂組成物の硬化物の熱伝導性を高めるために、アルミナ粒子等の熱伝導率が高いフィラーを樹脂に添加する方法が一般に用いられている（例えば、特許文献１参照）。 In order to increase the thermal conductivity of the cured product of the epoxy resin composition, a method of adding a filler having a high thermal conductivity such as alumina particles to the resin is generally used (for example, see Patent Document 1).
特開２００１－３４８４８８号公報JP 2001-348488 A
　しかしながら、エポキシ樹脂組成物にフィラーを含有させると、粘度が高くなる、硬化物としたときの接着強度が低下する等の性能への悪影響が生じる傾向がある。また、一般的にフィラーを高い含有率で含むエポキシ樹脂組成物は、薄膜化が困難になる傾向がある。
　上記状況に鑑み、本発明は、薄膜形成性と、硬化した状態での熱伝導性とに優れるエポキシ樹脂組成物、エポキシ樹脂硬化物、熱伝導フィルム、及びエポキシ樹脂硬化物の製造方法を提供することを課題とする。 However, when a filler is contained in the epoxy resin composition, there is a tendency that an adverse effect on performance such as an increase in viscosity or a decrease in adhesive strength when a cured product is produced. Moreover, generally the epoxy resin composition which contains a filler with a high content rate tends to become difficult to make a thin film.
In view of the above situation, the present invention provides an epoxy resin composition, an epoxy resin cured product, a thermally conductive film, and a method for producing an epoxy resin cured product that are excellent in thin film formability and thermal conductivity in a cured state. This is the issue.
　上記課題を解決するための具体的な手段は以下の通りである。
＜１＞エポキシ化合物と、硬化剤とを含み、スメクチック液晶構造を形成可能な反応誘起型のエポキシ樹脂組成物であり、フィラーを含まないか、フィラーの含有率が前記エポキシ樹脂組成物の不揮発分全体の２０質量％以下であるエポキシ樹脂組成物。
＜２＞前記スメクチック液晶構造はドメインを形成しており、前記ドメインの直径の平均値が２０μｍ以上である、＜１＞に記載のエポキシ樹脂組成物。
＜３＞前記スメクチック液晶構造はドメインを形成しており、前記ドメインは球晶を含む、＜１＞又は＜２＞に記載のエポキシ樹脂組成物。
＜４＞前記スメクチック液晶構造はネマチック液晶構造を経由して形成される、＜１＞～＜３＞のいずれか１項に記載のエポキシ樹脂組成物。
＜５＞１３０℃～１６０℃の範囲から選択されるいずれの硬化温度においてもスメクチック液晶構造を形成可能である、＜１＞～＜４＞のいずれか１項に記載のエポキシ樹脂組成物。
＜６＞１６０℃の硬化温度において３分以内にスメクチック液晶構造を形成可能である、＜１＞～＜５＞のいずれか１項に記載のエポキシ樹脂組成物。
＜７＞前記エポキシ化合物がメソゲン構造を有するエポキシ化合物を含む、＜１＞～＜６＞のいずれか１項に記載のエポキシ樹脂組成物。
＜８＞前記エポキシ化合物が下記一般式（Ｉ）で表される化合物を含む、＜１＞～＜７＞のいずれか１項に記載のエポキシ樹脂組成物。 Specific means for solving the above problems are as follows.
<1> A reaction-induced epoxy resin composition that includes an epoxy compound and a curing agent and is capable of forming a smectic liquid crystal structure, and does not contain a filler or the filler content is a non-volatile content of the epoxy resin composition. The epoxy resin composition which is 20 mass% or less of the whole.
<2> The epoxy resin composition according to <1>, wherein the smectic liquid crystal structure forms a domain, and an average value of the diameter of the domain is 20 μm or more.
<3> The epoxy resin composition according to <1> or <2>, wherein the smectic liquid crystal structure forms a domain, and the domain includes a spherulite.
<4> The epoxy resin composition according to any one of <1> to <3>, wherein the smectic liquid crystal structure is formed via a nematic liquid crystal structure.
<5> The epoxy resin composition according to any one of <1> to <4>, wherein the smectic liquid crystal structure can be formed at any curing temperature selected from the range of 130 ° C. to 160 ° C.
<6> The epoxy resin composition according to any one of <1> to <5>, wherein a smectic liquid crystal structure can be formed within 3 minutes at a curing temperature of 160 ° C.
<7> The epoxy resin composition according to any one of <1> to <6>, wherein the epoxy compound includes an epoxy compound having a mesogenic structure.
<8> The epoxy resin composition according to any one of <1> to <7>, wherein the epoxy compound includes a compound represented by the following general formula (I).
Figure JPOXMLDOC01-appb-C000002
 
Figure JPOXMLDOC01-appb-C000002
 
〔一般式（Ｉ）中、Ｒ１～Ｒ４はそれぞれ独立に、水素原子又は炭素数１～３のアルキル基を示す。〕
＜９＞前記エポキシ化合物が前記一般式（Ｉ）で表される化合物と２価フェノール化合物との反応生成物を含む、＜８＞に記載のエポキシ樹脂組成物。
＜１０＞前記硬化剤がフェノールノボラック樹脂を含む、＜１＞～＜９＞のいずれか１項に記載のエポキシ樹脂組成物。
＜１１＞前記フィラーがシリカ粒子、アルミナ粒子、酸化マグネシウム粒子、窒化アルミニウム粒子及び窒化ホウ素粒子からなる群より選択される少なくとも１種を含む、＜１＞～＜１０＞のいずれか１項に記載のエポキシ樹脂組成物。
＜１２＞＜１＞～＜１１＞のいずれか１項に記載のエポキシ樹脂組成物の硬化物である、エポキシ樹脂硬化物。
＜１３＞スメクチック液晶構造の周期構造を有し、前記周期構造の周期長が１．０ｎｍ～４．０ｎｍである、＜１２＞に記載のエポキシ樹脂硬化物。
＜１４＞＜１２＞又は＜１３＞に記載のエポキシ樹脂硬化物のフィルム状物である、熱伝導フィルム。
＜１５＞＜１＞～＜１１＞のいずれか１項に記載のエポキシ樹脂組成物を熱処理する工程を含み、前記熱処理は下記式を満たす温度Ｘ（℃）で行われる、エポキシ樹脂硬化物の製造方法。
　　　　　（Ｂ＋５℃）≦Ｘ≦（Ａ－５℃）
〔式中、Ａは前記エポキシ樹脂組成物がスメクチック液晶構造を形成可能な温度の上限値（℃）であり、Ｂは前記エポキシ樹脂組成物がスメクチック液晶構造を形成可能な温度の下限値（℃）である。〕
＜１６＞前記エポキシ樹脂組成物がフィルムの状態で前記熱処理が行われる、＜１５＞に記載のエポキシ樹脂硬化物の製造方法。 [In general formula (I), R 1 to R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ]
<9> The epoxy resin composition according to <8>, wherein the epoxy compound includes a reaction product of the compound represented by the general formula (I) and a divalent phenol compound.
<10> The epoxy resin composition according to any one of <1> to <9>, wherein the curing agent includes a phenol novolac resin.
<11> The <1> to <10>, wherein the filler includes at least one selected from the group consisting of silica particles, alumina particles, magnesium oxide particles, aluminum nitride particles, and boron nitride particles. Epoxy resin composition.
<12> A cured epoxy resin, which is a cured product of the epoxy resin composition according to any one of <1> to <11>.
<13> The cured epoxy resin according to <12>, having a periodic structure of a smectic liquid crystal structure, wherein the periodic length of the periodic structure is 1.0 nm to 4.0 nm.
<14> A heat conductive film which is a film-like product of the cured epoxy resin according to <12> or <13>.
<15> including a step of heat-treating the epoxy resin composition according to any one of <1> to <11>, wherein the heat treatment is performed at a temperature X (° C.) satisfying the following formula: Production method.
(B + 5 ℃) ≦ X ≦ (A-5 ℃)
[Wherein, A is an upper limit value (° C.) at which the epoxy resin composition can form a smectic liquid crystal structure, and B is a lower limit value (° C.) at which the epoxy resin composition can form a smectic liquid crystal structure. ). ]
<16> The method for producing a cured epoxy resin product according to <15>, wherein the heat treatment is performed with the epoxy resin composition in a film state.
　本発明によれば、薄膜形成性と、硬化した状態での熱伝導性とに優れるエポキシ樹脂組成物、エポキシ樹脂硬化物、熱伝導フィルム、及びエポキシ樹脂硬化物の製造方法が提供される。 According to the present invention, there are provided an epoxy resin composition, an epoxy resin cured product, a thermally conductive film, and a method for producing an epoxy resin cured product that are excellent in thin film formability and thermal conductivity in a cured state.
実施例１で作製したエポキシ樹脂組成物における、硬化温度と、ネマチック液晶構造又はスメクチック液晶構造を形成するまでの時間との関係を示す相図である。It is a phase diagram which shows the relationship between the curing temperature in the epoxy resin composition produced in Example 1, and time until forming a nematic liquid crystal structure or a smectic liquid crystal structure.
　以下、本発明について詳細に説明する。但し、本発明は以下の実施形態に限定されるものではない。以下の実施形態において、その構成要素（要素ステップ等も含む）は、特に明示した場合を除き、必須ではない。数値及びその範囲についても同様であり、本発明を制限するものではない。
　本明細書において「～」を用いて示された数値範囲には、「～」の前後に記載される数値がそれぞれ最小値及び最大値として含まれる。
　本明細書中に段階的に記載されている数値範囲において、一つの数値範囲で記載された上限値又は下限値は、他の段階的な記載の数値範囲の上限値又は下限値に置き換えてもよい。また、本明細書中に記載されている数値範囲において、その数値範囲の上限値又は下限値は、実施例に示されている値に置き換えてもよい。
　本明細書において組成物中の各成分の含有率は、組成物中に各成分に該当する物質が複数種存在する場合、特に断らない限り、組成物中に存在する当該複数種の物質の合計の含有率を意味する。
　本明細書において組成物中の各成分の粒子径は、組成物中に各成分に該当する粒子が複数種存在する場合、特に断らない限り、組成物中に存在する当該複数種の粒子の混合物についての値を意味する。
　本発明において、平均厚み（厚みの平均値ともいう）は、対象物の無作為に選んだ５点の厚みを測定し、その算術平均値として与えられる値とする。厚みは、マイクロメーター等を用いて測定することができる。 Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and the present invention is not limited thereto.
In the present specification, numerical values indicated by using “to” include numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range. Good. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
In the present specification, the content of each component in the composition is the sum of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. It means the content rate of.
In the present specification, the particle diameter of each component in the composition is a mixture of the plurality of types of particles present in the composition unless there is a specific indication when there are a plurality of types of particles corresponding to each component in the composition. Means the value of.
In the present invention, the average thickness (also referred to as the average value of the thickness) is a value given as an arithmetic average value obtained by measuring the thickness of five randomly selected objects. The thickness can be measured using a micrometer or the like.
＜エポキシ樹脂組成物＞
　本実施形態のエポキシ樹脂組成物は、エポキシ化合物と、硬化剤とを含み、スメクチック液晶構造を形成可能な反応誘起型のエポキシ樹脂組成物であり、フィラーを含まないか、フィラーの含有率が前記エポキシ樹脂組成物の不揮発分全体の２０質量％以下である。 <Epoxy resin composition>
The epoxy resin composition of the present embodiment is a reaction-induced epoxy resin composition that includes an epoxy compound and a curing agent and can form a smectic liquid crystal structure, and does not contain a filler or the filler content is It is 20 mass% or less of the whole non volatile matter of an epoxy resin composition.
　本実施形態のエポキシ樹脂組成物（以下、単にエポキシ樹脂組成物とも称する）は、フィラーを含まないか、その含有率がエポキシ樹脂組成物の不揮発分全体の２０質量％以下であるため、フィラーを含有させることによる薄膜形成性の低下が抑制される。また、エポキシ樹脂組成物が反応誘起型であるため、硬化温度における硬化前の流動性に優れ、良好な薄膜形成性が達成されると考えられる。 The epoxy resin composition of the present embodiment (hereinafter also simply referred to as an epoxy resin composition) does not contain a filler, or its content is 20% by mass or less of the entire nonvolatile content of the epoxy resin composition. The deterioration of the thin film formation property by containing is suppressed. In addition, since the epoxy resin composition is a reaction-induced type, it is considered that excellent fluidity before curing at a curing temperature is achieved and good thin film formability is achieved.
　さらに、本実施形態のエポキシ樹脂組成物はスメクチック液晶構造を形成可能であるため、硬化後の良好な熱伝導性が達成されると考えられる。 Furthermore, since the epoxy resin composition of the present embodiment can form a smectic liquid crystal structure, it is considered that good thermal conductivity after curing is achieved.
　本明細書において「反応誘起型のエポキシ樹脂組成物」とは、硬化反応が開始する以前に液晶構造が形成されず、等方構造（等方相）であるが、硬化反応の進行とともに液晶構造を形成する性質を有するエポキシ樹脂組成物のことを意味する。反応誘起型でないエポキシ樹脂組成物としては、硬化反応が開始する以前に液晶構造がすでに形成され、液晶構造の状態で硬化反応が進行する樹脂組成物が挙げられる。 In the present specification, the “reaction-inducing epoxy resin composition” is an isotropic structure (isotropic phase) in which the liquid crystal structure is not formed before the curing reaction starts, but the liquid crystal structure is developed with the progress of the curing reaction. It means an epoxy resin composition having the property of forming. Examples of the epoxy resin composition that is not reaction-induced include a resin composition in which a liquid crystal structure is already formed before the curing reaction starts and the curing reaction proceeds in the state of the liquid crystal structure.
　エポキシ樹脂組成物は、液晶構造の状態である場合よりも等方構造の状態である場合の方が流動性が高い。このため、反応誘起型のエポキシ樹脂組成物は、反応誘起型でないエポキシ樹脂組成物に比べ、硬化温度における硬化前の流動性が高い傾向にある。また、反応誘起型のエポキシ樹脂組成物も、反応誘起型でないエポキシ樹脂組成物と同様に硬化後には液晶構造を形成するため、高い熱伝導率が得られる。 The epoxy resin composition has higher fluidity in the isotropic structure state than in the liquid crystal structure state. For this reason, reaction-induced epoxy resin compositions tend to have higher fluidity before curing at the curing temperature than non-reaction-induced epoxy resin compositions. Moreover, since the reaction-induced epoxy resin composition also forms a liquid crystal structure after curing in the same manner as the non-reaction-induced epoxy resin composition, high thermal conductivity can be obtained.
　エポキシ樹脂組成物が反応誘起型であるか否かは、エポキシ化合物の分子構造及び硬化剤の分子構造に依存する。 Whether or not the epoxy resin composition is reaction-induced depends on the molecular structure of the epoxy compound and the molecular structure of the curing agent.
　本実施形態のエポキシ樹脂組成物は、エポキシ化合物と硬化剤の反応によってスメクチック液晶構造を形成可能である。硬化剤と反応してスメクチック液晶構造等の液晶構造を形成可能なエポキシ化合物（以下、液晶性エポキシ化合物とも称する）としては、メソゲン構造を有するエポキシ化合物が挙げられる。本明細書において「メソゲン構造を有するエポキシ化合物」とは、エポキシ基と、メソゲン構造とを有する化合物を意味する。メソゲン構造としては、ビフェニル構造、ターフェニル構造、ターフェニル類縁構造、アントラセン構造、これらのメソゲン構造の２つ以上がアゾメチン基又はエステル基で接続された構造、フェニルベンゾエート構造、シクロヘキシルベンゾエート構造等が挙げられる。 The epoxy resin composition of the present embodiment can form a smectic liquid crystal structure by a reaction between an epoxy compound and a curing agent. An epoxy compound having a mesogenic structure is an example of an epoxy compound that can react with a curing agent to form a liquid crystal structure such as a smectic liquid crystal structure (hereinafter also referred to as a liquid crystalline epoxy compound). In the present specification, the “epoxy compound having a mesogen structure” means a compound having an epoxy group and a mesogen structure. Examples of the mesogen structure include a biphenyl structure, a terphenyl structure, a terphenyl analog structure, an anthracene structure, a structure in which two or more of these mesogen structures are connected by an azomethine group or an ester group, a phenylbenzoate structure, a cyclohexylbenzoate structure, and the like. It is done.
　メソゲン構造を有するエポキシ化合物は、硬化剤と反応して樹脂マトリックスを形成する際に、その分子中のメソゲン構造に由来する高次構造（周期構造ともいう）を樹脂マトリックス中に形成する。 When an epoxy compound having a mesogenic structure reacts with a curing agent to form a resin matrix, a higher order structure (also referred to as a periodic structure) derived from the mesogenic structure in the molecule is formed in the resin matrix.
　本明細書において「樹脂マトリックス」とは、エポキシ樹脂組成物の硬化物（以下、エポキシ樹脂硬化物とも称する）のうち、エポキシ化合物と硬化物の反応物に相当する部分を意味する。 In the present specification, the “resin matrix” means a portion corresponding to a reaction product of an epoxy compound and a cured product in a cured product of an epoxy resin composition (hereinafter also referred to as an epoxy resin cured product).
　本明細書において、樹脂マトリックス中に形成される高次構造（周期構造）とは、樹脂マトリックス中に分子が配向した状態で配列している状態（例えば、樹脂マトリックス中に結晶構造又は液晶構造が存在する状態）を意味する。このような結晶構造又は液晶構造は、例えば、直交ニコル下での偏光顕微鏡による観察又はＸ線散乱により、その存在を直接確認することができる。あるいは、結晶構造又は液晶構造が存在すると樹脂の貯蔵弾性率の温度に対する変化が小さくなる性質を利用して、貯蔵弾性率の温度に対する変化を測定することにより、結晶構造又は液晶構造の存在を間接的に確認できる。 In this specification, a higher order structure (periodic structure) formed in a resin matrix means a state in which molecules are aligned in a resin matrix (for example, a crystal structure or a liquid crystal structure is present in the resin matrix). Existing state). The presence of such a crystal structure or liquid crystal structure can be directly confirmed by, for example, observation with a polarizing microscope under crossed Nicols or X-ray scattering. Alternatively, the presence of the crystal structure or liquid crystal structure is indirectly measured by measuring the change in storage modulus of the resin with respect to temperature by utilizing the property that the change in the storage modulus of the resin with respect to temperature is reduced when the crystal structure or liquid crystal structure is present. Can be confirmed.
　メソゲン構造に由来する規則性の高い高次構造としては、ネマチック液晶構造、スメクチック液晶構造等が挙げられる。ネマチック液晶構造は、分子長軸が一様な方向を向いており、配向秩序のみを持つ液晶構造である。これに対し、スメクチック液晶構造は配向秩序に加えて一次元の位置の秩序を持ち、一定周期の層構造を有する液晶構造である。また、スメクチック液晶構造の同一の周期構造内部では、層構造の周期の方向が一様である。すなわち、分子の秩序性は、ネマチック液晶構造よりもスメクチック液晶構造の方が高い。秩序性の高い周期構造が樹脂マトリックス中に形成されると、熱伝導の媒体であるフォノンが散乱するのを抑制することができる。このため、ネマチック液晶構造を有する樹脂マトリックスよりもスメクチック液晶構造を有する樹脂マトリックスの方が、熱伝導率が高くなる傾向にある。 Examples of highly ordered higher order structures derived from mesogenic structures include nematic liquid crystal structures and smectic liquid crystal structures. The nematic liquid crystal structure is a liquid crystal structure in which the molecular long axis is oriented in a uniform direction and has only alignment order. On the other hand, the smectic liquid crystal structure is a liquid crystal structure having a one-dimensional positional order in addition to the alignment order and having a layer structure with a constant period. Further, the direction of the period of the layer structure is uniform within the same periodic structure of the smectic liquid crystal structure. That is, the order of the molecules is higher in the smectic liquid crystal structure than in the nematic liquid crystal structure. When a highly ordered periodic structure is formed in the resin matrix, it is possible to suppress scattering of phonons that are heat conductive media. For this reason, the thermal conductivity tends to be higher in the resin matrix having the smectic liquid crystal structure than in the resin matrix having the nematic liquid crystal structure.
　本実施形態では、エポキシ化合物が硬化剤と反応すると、スメクチック液晶構造が形成される。エポキシ化合物と硬化剤との反応によってスメクチック液晶構造が形成されるか否かは、エポキシ化合物の分子構造、硬化剤の分子構造、硬化温度等に依存する。
　本実施形態では、樹脂マトリックス中に形成された周期構造の全体がスメクチック液晶構造であっても、一部がスメクチック液晶構造であってもよい。 In this embodiment, when the epoxy compound reacts with the curing agent, a smectic liquid crystal structure is formed. Whether or not a smectic liquid crystal structure is formed by the reaction between the epoxy compound and the curing agent depends on the molecular structure of the epoxy compound, the molecular structure of the curing agent, the curing temperature, and the like.
In the present embodiment, the entire periodic structure formed in the resin matrix may be a smectic liquid crystal structure or a part thereof may be a smectic liquid crystal structure.
　樹脂マトリックス中に形成された周期構造がスメクチック液晶構造を含んでいるか否かは、下記方法により判断することができる。
　ＣｕＫα１線を用い、管電圧４０ｋＶ、管電流２０ｍＡ、２θが０．５°～３０°の範囲で、Ｘ線解析装置（例えば、株式会社リガク製）を用いてＸ線回折測定を行う。２θが１°～１０°の範囲に回折ピークが存在する場合には、周期構造がスメクチック液晶構造を含んでいると判断される。
　熱伝導性の観点からは、樹脂マトリックス中の周期構造全体におけるスメクチック液晶構造の割合は、６０体積％以上であることが好ましく、８０体積％以上であることがより好ましい。 Whether or not the periodic structure formed in the resin matrix includes a smectic liquid crystal structure can be determined by the following method.
X-ray diffraction measurement is performed using an X-ray analyzer (for example, manufactured by Rigaku Corporation) using a CuK α 1 line and a tube voltage of 40 kV, a tube current of 20 mA, and 2θ in the range of 0.5 ° to 30 °. When a diffraction peak exists in the range of 2θ of 1 ° to 10 °, it is determined that the periodic structure includes a smectic liquid crystal structure.
From the viewpoint of thermal conductivity, the ratio of the smectic liquid crystal structure in the entire periodic structure in the resin matrix is preferably 60% by volume or more, and more preferably 80% by volume or more.
　周期構造全体におけるスメクチック液晶構造の割合は、例えば、エポキシ樹脂硬化物を所定の厚さ（例えば、５０μｍ）になるまで研磨して偏光顕微鏡で観察することにより、簡易的に測定することができる。具体的には、スメクチック液晶構造が形成されたエポキシ樹脂硬化物を５０μｍの厚さに研磨し、偏光顕微鏡（例えば、株式会社ニコン製、製品名：「ＯＰＴＩＰＨＯＴ２－ＰＯＬ」）で観察してスメクチック液晶構造の周期構造の面積を測定し、偏光顕微鏡で観察した視野全体の面積に対する百分率を求めることにより、周期構造全体におけるスメクチック液晶構造の割合を簡易的に測定することができる。 The ratio of the smectic liquid crystal structure in the entire periodic structure can be easily measured by, for example, polishing the epoxy resin cured product to a predetermined thickness (for example, 50 μm) and observing with a polarizing microscope. Specifically, a cured epoxy resin having a smectic liquid crystal structure is polished to a thickness of 50 μm, and observed with a polarizing microscope (for example, product name: “OPTIPHOT2-POL” manufactured by Nikon Corporation) to produce a smectic liquid crystal. The ratio of the smectic liquid crystal structure in the entire periodic structure can be easily measured by measuring the area of the periodic structure of the structure and determining the percentage of the entire field of view observed with a polarizing microscope.
　スメクチック液晶構造の周期構造は、周期長（１周期の長さ）が、１．０ｎｍ以上であることが好ましく、２．０ｎｍ以上であることがより好ましい。周期長が１．０ｎｍ以上であることにより、より高い熱伝導率を発揮することが可能である。周期長は４．０ｎｍであってよく、１．０ｎｍ～４．０ｎｍであることが好ましい。 The periodic structure of the smectic liquid crystal structure preferably has a period length (length of one period) of 1.0 nm or more, and more preferably 2.0 nm or more. When the period length is 1.0 nm or more, higher thermal conductivity can be exhibited. The period length may be 4.0 nm, and is preferably 1.0 nm to 4.0 nm.
　周期構造の周期長は、広角Ｘ線回折装置（例えば、株式会社リガク製、製品名：「ＲＩＮＴ２５００ＨＬ」）を用いて、上記の測定条件でエポキシ樹脂硬化物を測定試料としてＸ線回折を行い、これにより得られた回折角度を、下記ブラッグの式により換算することにより得られる。 The periodic length of the periodic structure is obtained by performing X-ray diffraction using a cured epoxy resin product as a measurement sample under the above measurement conditions using a wide-angle X-ray diffractometer (for example, Rigaku Corporation, product name: “RINT2500HL”). The diffraction angle thus obtained can be obtained by converting the following Bragg equation.
　ブラッグの式：２ｄｓｉｎθ＝ｎλ
　ここで、ｄは１周期の長さ、θは回折角度、ｎは反射次数、λはＸ線波長（０．１５４０６ｎｍ）を示す。 Bragg's formula: 2 dsin θ = nλ
Here, d is the length of one period, θ is the diffraction angle, n is the reflection order, and λ is the X-ray wavelength (0.15406 nm).
　エポキシ樹脂組成物がスメクチック液晶構造を形成する過程は、特に制限されない。急激な体積収縮を抑制する観点からは、ネマチック液晶構造を経由してスメクチック液晶構造を形成することが好ましい。
　これは、等方構造からネマチック液晶構造を経由せず、直接スメクチック液晶構造に転移すると、密度の変化が大きいため、体積収縮が急激に生じる傾向にあるからである。 The process in which the epoxy resin composition forms a smectic liquid crystal structure is not particularly limited. From the viewpoint of suppressing rapid volume shrinkage, it is preferable to form a smectic liquid crystal structure via a nematic liquid crystal structure.
This is because when the transition from the isotropic structure to the smectic liquid crystal structure directly without passing through the nematic liquid crystal structure, the density change is large, and thus volume shrinkage tends to occur rapidly.
　エポキシ樹脂組成物がネマチック液晶構造を経由してスメクチック液晶構造を形成するようにする方法としては、ネマチック液晶構造を広い温度領域で発現するエポキシ化合物を用いる方法が挙げられる。 As a method for causing the epoxy resin composition to form a smectic liquid crystal structure via a nematic liquid crystal structure, a method using an epoxy compound that exhibits a nematic liquid crystal structure in a wide temperature range can be mentioned.
　熱伝導性の観点からは、エポキシ樹脂組成物により形成されるスメクチック液晶構造はドメインを形成しており、ドメインの直径の平均値が２０μｍ以上であることが好ましく、４０μｍ以上であることがより好ましく、６０μｍ以上であることがさらに好ましい。等方性の観点からは、ドメインの直径の平均値は１００μｍ以下であることが好ましい。 From the viewpoint of thermal conductivity, the smectic liquid crystal structure formed by the epoxy resin composition forms a domain, and the average value of the domain diameter is preferably 20 μm or more, more preferably 40 μm or more. More preferably, it is 60 μm or more. From the viewpoint of isotropic property, the average value of the domain diameters is preferably 100 μm or less.
　本明細書において「ドメイン」とは、樹脂マトリックス中で、一方向に周期構造が形成された部分に相当し、周期構造が形成されていない部分又はそのドメインの周期構造と異なる方向に周期構造が形成された部分で囲まれた島状の領域を意味する。 In this specification, the “domain” corresponds to a portion in which a periodic structure is formed in one direction in the resin matrix, and the periodic structure is in a direction different from the portion where the periodic structure is not formed or the periodic structure of the domain. It means an island-like region surrounded by the formed part.
　ドメインの直径及びその平均値は、エポキシ樹脂硬化物の観察断面に現れるドメインの断面の直径及びその平均値として擬似的に測定できる。
　ドメインの断面の直径は、例えば、上述したようなエポキシ樹脂硬化物の偏光顕微鏡観察により測定される。
　ドメインの断面の直径の平均値は、エポキシ樹脂硬化物の観察断面に現れるドメインのうち、無作為に選択した１０個のドメインについてその直径の測定を行い、その算術平均値をスメクチック液晶構造のドメインの直径とする。 The diameter of the domain and its average value can be measured in a pseudo manner as the diameter of the cross section of the domain appearing in the observed cross section of the cured epoxy resin and its average value.
The diameter of the cross section of the domain is measured, for example, by polarizing microscope observation of the cured epoxy resin as described above.
The average value of the diameter of the cross section of the domain is measured for 10 randomly selected domains among the domains appearing in the observed cross section of the epoxy resin cured product, and the arithmetic average value is calculated as the domain of the smectic liquid crystal structure. The diameter of
　本明細書においてドメインの直径とは、ドメインの形状が真円でない形状（楕円、多角形等）の場合は、ドメインの最大径を意味する。最大径は、エポキシ樹脂硬化物の観察断面に現れるドメインの輪郭線上に位置する任意の２点を結ぶ線分のうち、長さが最長である線分の長さとする。 In this specification, the diameter of a domain means the maximum diameter of a domain when the shape of the domain is not a perfect circle (ellipse, polygon, etc.). The maximum diameter is the length of the longest line segment connecting the two arbitrary points located on the contour line of the domain appearing on the observation cross section of the cured epoxy resin.
　ドメインの直径は、例えば、エポキシ樹脂組成物の硬化条件によって制御することができる。一般に、エポキシ樹脂組成物の硬化温度が低いほど、ドメインの成長速度が遅くなり、結果としてドメインの直径が大きくなる傾向にある。また、エポキシ樹脂組成物の硬化時間が長いほど、ドメインが充分に成長して直径が大きくなる傾向にある。 The diameter of the domain can be controlled by, for example, the curing conditions of the epoxy resin composition. In general, the lower the curing temperature of the epoxy resin composition, the slower the growth rate of the domains, with the result that the domain diameter tends to increase. Further, the longer the curing time of the epoxy resin composition, the more the domain grows and the diameter tends to increase.
　直径が大きいドメインを得る観点からは、エポキシ樹脂組成物の硬化温度は１６０℃以下であることが好ましく、１５０℃以下であることがより好ましく、１４０℃以下であることがさらに好ましい。また、エポキシ樹脂組成物の硬化時間は３０秒以上であることが好ましく、１分以上であることがより好ましい。 From the viewpoint of obtaining a domain having a large diameter, the curing temperature of the epoxy resin composition is preferably 160 ° C. or lower, more preferably 150 ° C. or lower, and further preferably 140 ° C. or lower. Further, the curing time of the epoxy resin composition is preferably 30 seconds or longer, and more preferably 1 minute or longer.
　一方、硬化時間の観点からは、エポキシ樹脂組成物の硬化温度は低すぎないことが好ましい。従って、硬化温度は１３０℃以上であることが好ましい。また、エポキシ樹脂組成物の硬化時間の短縮の観点からは、硬化時間は５分以内であることが好ましく、３分以内であることがより好ましい。 On the other hand, from the viewpoint of curing time, the curing temperature of the epoxy resin composition is preferably not too low. Accordingly, the curing temperature is preferably 130 ° C. or higher. Moreover, from the viewpoint of shortening the curing time of the epoxy resin composition, the curing time is preferably within 5 minutes, and more preferably within 3 minutes.
　ある実施態様では、エポキシ樹脂組成物は、１３０℃～１６０℃の範囲から選択されるいずれの硬化温度においてもスメクチック液晶構造を形成可能である。１３０℃～１６０℃の硬化温度範囲を経れば、一定の硬化温度でなくてもスメクチック液晶構造を形成可能である。例えば３０℃から１８０℃まで５℃／分で昇温する過程においてもスメクチック液晶構造を形成可能である。
　ある実施態様では、エポキシ樹脂組成物は、１６０℃の硬化温度において３分以内にスメクチック液晶構造を形成可能である。 In some embodiments, the epoxy resin composition is capable of forming a smectic liquid crystal structure at any curing temperature selected from the range of 130 ° C to 160 ° C. If a curing temperature range of 130 ° C. to 160 ° C. is passed, a smectic liquid crystal structure can be formed even if the curing temperature is not constant. For example, a smectic liquid crystal structure can be formed even in the process of raising the temperature from 30 ° C. to 180 ° C. at 5 ° C./min.
In one embodiment, the epoxy resin composition is capable of forming a smectic liquid crystal structure within 3 minutes at a curing temperature of 160 ° C.
　熱伝導性の観点からは、エポキシ樹脂組成物により形成されるスメクチック液晶構造は、ドメインの状態であり、球晶を含むことが好ましい。本明細書において球晶とは、立体形状が球体状、楕円体状又は円盤状であるドメインを意味する。スメクチック液晶構造のドメインが球晶を含むか否かは、例えば、エポキシ樹脂硬化物の観察断面に現れるドメインの形状が円形、楕円形等であるか否かによって判断できる。 From the viewpoint of thermal conductivity, the smectic liquid crystal structure formed by the epoxy resin composition is in a domain state and preferably contains spherulites. In this specification, the spherulite means a domain whose three-dimensional shape is a sphere, an ellipsoid, or a disk. Whether the domain of the smectic liquid crystal structure contains spherulites can be determined, for example, by determining whether the shape of the domain appearing in the observed cross section of the cured epoxy resin is circular, elliptical, or the like.
　ドメインを球晶の状態にする方法としては、個々のドメインが隣接するドメインによって変形しないようにして成長させる方法が挙げられる。例えば、硬化前のエポキシ樹脂組成物に溶剤を含有させる方法が挙げられる。 As a method of making a domain into a spherulite state, there is a method in which each domain is grown without being deformed by an adjacent domain. For example, the method of making the epoxy resin composition before hardening contain a solvent is mentioned.
　一般に、スメクチック液晶構造を形成する核の間隔は狭いため、硬化に伴ってスメクチック液晶構造のドメインが成長する過程で、ドメインとドメインとが衝突する。その結果、個々のドメインは球晶にならず、断面が多角形の形状等になる傾向にある。一方、硬化前のエポキシ樹脂組成物に溶剤を含有させ、溶剤を揮発させながら硬化させると、溶剤によりエポキシ樹脂組成物が希釈されているため、スメクチック液晶構造を形成する核の間隔が広くなる。その結果、硬化に伴ってスメクチック液晶構造が成長する過程で、スメクチック液晶構造のドメインとドメインが衝突しなくなり、個々のドメインが球晶になる傾向にある。 Generally, since the interval between the nuclei forming the smectic liquid crystal structure is narrow, the domains collide with each other in the process of growing the domain of the smectic liquid crystal structure with hardening. As a result, the individual domains tend not to be spherulites but to have a polygonal cross section. On the other hand, when the epoxy resin composition before curing contains a solvent and is cured while volatilizing the solvent, the epoxy resin composition is diluted with the solvent, so that the interval between the nuclei forming the smectic liquid crystal structure is widened. As a result, in the process where the smectic liquid crystal structure grows with hardening, the domains of the smectic liquid crystal structure do not collide with each other and the individual domains tend to be spherulites.
　以下、本実施形態のエポキシ樹脂組成物に含まれる成分について詳細に説明する。 Hereinafter, the components contained in the epoxy resin composition of the present embodiment will be described in detail.
（エポキシ化合物）
　エポキシ化合物は、硬化剤と反応してスメクチック液晶構造を形成可能なものであれば特に制限されず、１種のみでも２種以上であってもよい。 (Epoxy compound)
The epoxy compound is not particularly limited as long as it can form a smectic liquid crystal structure by reacting with a curing agent, and may be one type or two or more types.
　スメクチック液晶構造を効率よく形成する観点から、エポキシ化合物は、メソゲン構造を有するエポキシ化合物として下記一般式（Ｉ）で表される化合物を含むことが好ましい。一般式（Ｉ）で表される化合物は、１種のみでも２種以上であってもよい。 From the viewpoint of efficiently forming a smectic liquid crystal structure, the epoxy compound preferably includes a compound represented by the following general formula (I) as an epoxy compound having a mesogenic structure. 1 type or 2 types or more may be sufficient as the compound represented by general formula (I).
Figure JPOXMLDOC01-appb-C000003
 
Figure JPOXMLDOC01-appb-C000003
 
　一般式（Ｉ）中、Ｒ１～Ｒ４はそれぞれ独立に、水素原子又は炭素数１～３のアルキル基を示す。Ｒ１～Ｒ４はそれぞれ独立に、水素原子又は炭素数１～２のアルキル基であることが好ましく、水素原子又はメチル基であることがより好ましく、水素原子であることがさらに好ましい。また、Ｒ１～Ｒ４のうちの２個～４個が水素原子であることが好ましく、３個又は４個が水素原子であることがより好ましく、４個すべてが水素原子であることがさらに好ましい。Ｒ１～Ｒ４のいずれかが炭素数１～３のアルキル基である場合、Ｒ１及びＲ４の少なくとも一方が炭素数１～３のアルキル基であることが好ましい。 In general formula (I), R 1 to R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R 1 to R 4 are each independently preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. Also, it is preferable that 2 to 4 of R 1 to R 4 are hydrogen atoms, more preferably 3 or 4 are hydrogen atoms, and more preferably that all 4 are hydrogen atoms. preferable. When any of R 1 to R 4 is an alkyl group having 1 to 3 carbon atoms, at least one of R 1 and R 4 is preferably an alkyl group having 1 to 3 carbon atoms.
　一般式（Ｉ）で表される化合物の好ましい例は、例えば、特開２０１１－７４３６６号公報に記載されている。具体的には、４－｛４－（２，３－エポキシプロポキシ）フェニル｝シクロヘキシル＝４－（２，３－エポキシプロポキシ）ベンゾエート及び４－｛４－（２，３－エポキシプロポキシ）フェニル｝シクロヘキシル＝４－（２，３－エポキシプロポキシ）－３－メチルベンゾエートからなる群より選択される少なくとも１種の化合物が好ましい例として挙げられる。 Preferred examples of the compound represented by the general formula (I) are described in, for example, JP-A-2011-74366. Specifically, 4- {4- (2,3-epoxypropoxy) phenyl} cyclohexyl = 4- (2,3-epoxypropoxy) benzoate and 4- {4- (2,3-epoxypropoxy) phenyl} cyclohexyl = At least one compound selected from the group consisting of 4- (2,3-epoxypropoxy) -3-methylbenzoate is a preferred example.
　エポキシ化合物の少なくとも一部は、後述の硬化剤等（プレポリマー化剤）と反応して得られたプレポリマーの状態であってもよい。一般式（Ｉ）で表される化合物を含め、分子中にメソゲン構造を有するエポキシ化合物は一般的に結晶化し易く、溶媒への溶解度はその他のエポキシ樹脂化合物と比べると低いものが多い。メソゲン構造を有するエポキシ化合物の一部を重合させてプレポリマーとすることで、結晶化が抑制され、エポキシ樹脂組成物の成形性が向上する傾向にある。 At least a part of the epoxy compound may be in a prepolymer state obtained by reacting with a curing agent (prepolymerizing agent) described later. In general, an epoxy compound having a mesogen structure in the molecule including the compound represented by the general formula (I) is easily crystallized, and its solubility in a solvent is often lower than that of other epoxy resin compounds. By polymerizing a part of the epoxy compound having a mesogenic structure to form a prepolymer, crystallization is suppressed and the moldability of the epoxy resin composition tends to be improved.
　プレポリマー化剤は、後述の硬化剤と同じものであっても別のものであってもよい。具体的には、プレポリマー化剤としては、１つのベンゼン環に２個の水酸基を置換基として有する化合物（２価フェノール化合物）が好ましい。２価フェノール化合物としては、カテコール、レゾルシノール、ハイドロキノン、これらの誘導体等が挙げられる。２価フェノール化合物の誘導体としては、ベンゼン環に炭素数１～８のアルキル基等が置換した化合物が挙げられる。これらの２価フェノール化合物の中でも、レゾルシノール及びハイドロキノンからなる群より選択される少なくとも１種を用いることが硬化物の熱伝導率を向上させる観点から好ましく、ハイドロキノンを用いることがより好ましい。ハイドロキノンは２つの水酸基がパラ位の位置関係となるように置換されている構造であるため、エポキシ化合物と反応させて得られるプレポリマーは直線構造となりやすい。このため、分子のスタッキング性が高く、高次構造をより形成し易いと考えられる。
　プレポリマー化に用いるプレポリマー化剤は、１種のみでも２種以上であってもよい。 The prepolymerizing agent may be the same as or different from the curing agent described later. Specifically, the prepolymerizing agent is preferably a compound (divalent phenol compound) having two hydroxyl groups as substituents on one benzene ring. Examples of the dihydric phenol compound include catechol, resorcinol, hydroquinone, and derivatives thereof. Examples of the derivative of the divalent phenol compound include compounds in which an alkyl group having 1 to 8 carbon atoms is substituted on the benzene ring. Among these dihydric phenol compounds, it is preferable to use at least one selected from the group consisting of resorcinol and hydroquinone from the viewpoint of improving the thermal conductivity of the cured product, and it is more preferable to use hydroquinone. Since hydroquinone has a structure in which two hydroxyl groups are substituted so as to have a para-position, a prepolymer obtained by reacting with an epoxy compound tends to have a linear structure. For this reason, it is considered that the stacking property of molecules is high and higher-order structures are more easily formed.
The prepolymerizing agent used for prepolymerization may be one kind or two or more kinds.
　エポキシ化合物をプレポリマー化する場合、エポキシ化合物とプレポリマー化剤の配合割合は特に制限されず、所望の分子量、エポキシ化合物全体に対する比率等に応じて選択できる。 When prepolymerizing the epoxy compound, the blending ratio of the epoxy compound and the prepolymerizing agent is not particularly limited, and can be selected according to a desired molecular weight, a ratio to the whole epoxy compound, and the like.
　エポキシ化合物をプレポリマー化する場合のエポキシ化合物とプレポリマー化剤の配合割合は、エポキシ化合物中のエポキシ基とプレポリマー化剤中の水酸基の当量比（エポキシ基／水酸基）が好ましくは１００／５～１００／２５、より好ましくは１００／１０～１００／１５となるような配合割合であることが好ましい。 When the epoxy compound is prepolymerized, the mixing ratio of the epoxy compound and the prepolymerizing agent is preferably the equivalent ratio of the epoxy group in the epoxy compound to the hydroxyl group in the prepolymerizing agent (epoxy group / hydroxyl group). The blending ratio is preferably in the range of ˜100 / 25, more preferably 100/10 to 100/15.
　エポキシ化合物の含有率は、成形性及び接着性の観点から、エポキシ樹脂組成物の全不揮発分中、５体積％～４０体積％であることが好ましく、１０体積％～３５体積％であることがより好ましく、１５体積％～３５体積％であることがさらに好ましく、１５体積％～３０体積％であることが特に好ましい。 The content of the epoxy compound is preferably 5% by volume to 40% by volume and preferably 10% by volume to 35% by volume in the total nonvolatile content of the epoxy resin composition from the viewpoint of moldability and adhesiveness. More preferably, it is 15 volume% to 35 volume%, further preferably 15 volume% to 30 volume%.
　本明細書において、エポキシ樹脂組成物の全不揮発分に対するエポキシ化合物の体積基準の含有率は、次式により求めた値とする。
　エポキシ化合物の全不揮発分に対する含有率（体積％）＝｛（Ｂｗ／Ｂｄ）／（（Ａｗ／Ａｄ）＋（Ｂｗ／Ｂｄ）＋（Ｃｗ／Ｃｄ）＋（Ｄｗ／Ｄｄ））｝×１００
　ここで、各変数は以下の通りである。
　Ａｗ：フィラーの質量組成比（質量％）
　Ｂｗ：エポキシ化合物の質量組成比（質量％）
　Ｃｗ：硬化剤の質量組成比（質量％）
　Ｄｗ：その他の任意成分（溶媒を除く）の質量組成比（質量％）
　Ａｄ：フィラーの比重
　Ｂｄ：エポキシ化合物の比重
　Ｃｄ：硬化剤の比重
　Ｄｄ：その他の任意成分（溶媒を除く）の比重 In this specification, the volume-based content of the epoxy compound with respect to the total nonvolatile content of the epoxy resin composition is a value determined by the following formula.
Content (% by volume) of epoxy compound with respect to the total nonvolatile content = {(Bw / Bd) / ((Aw / Ad) + (Bw / Bd) + (Cw / Cd) + (Dw / Dd))} × 100
Here, each variable is as follows.
Aw: Mass composition ratio of filler (% by mass)
Bw: mass composition ratio of epoxy compound (mass%)
Cw: mass composition ratio (% by mass) of curing agent
Dw: mass composition ratio (% by mass) of other optional components (excluding solvent)
Ad: Specific gravity of filler Bd: Specific gravity of epoxy compound Cd: Specific gravity of curing agent Dd: Specific gravity of other optional components (excluding solvent)
　エポキシ樹脂組成物に含まれるエポキシ化合物は、液晶性エポキシ化合物と、液晶性エポキシ化合物以外のその他のエポキシ化合物との組み合わせであってもよい。その他のエポキシ化合物としては、ビスフェノールＡ、ビスフェノールＦ、ビスフェノールＳ、フェノールノボラック、クレゾールノボラック、レゾルシノールノボラック等のフェノール化合物のグリシジルエーテル；ブタンジオール、ポリエチレングリコール、ポリプロピレングリコール等のアルコール化合物のグリシジルエーテル；フタル酸、イソフタル酸、テトラヒドロフタル酸等のカルボン酸化合物のグリシジルエステル；アニリン、イソシアヌル酸等の窒素原子に結合した活性水素をグリシジル基で置換したもの等のグリシジル型（メチルグリシジル型も含む）エポキシ化合物；分子内のオレフィン結合をエポキシ化して得られるビニルシクロヘキセンエポキシド、３，４－エポキシシクロヘキシルメチル－３，４－エポキシシクロヘキサンカルボキシレート、２－（３，４－エポキシ）シクロヘキシル－５，５－スピロ（３，４－エポキシ）シクロヘキサン－ｍ－ジオキサン等の脂環型エポキシ化合物；ビス（４－ヒドロキシ）チオエーテルのエポキシ化物；パラキシリレン変性フェノール樹脂、メタキシリレンパラキシリレン変性フェノール樹脂、テルペン変性フェノール樹脂、ジシクロペンタジエン変性フェノール樹脂、シクロペンタジエン変性フェノール樹脂、多環芳香環変性フェノール樹脂、ナフタレン環含有フェノール樹脂等のグリシジルエーテル；スチルベン型エポキシ化合物；ハロゲン化フェノールノボラック型エポキシ化合物など（但し、これらのうち液晶性エポキシ化合物を除く）が挙げられる。その他のエポキシ化合物は、１種を単独で用いてもよく、２種以上を併用してもよい。 The epoxy compound contained in the epoxy resin composition may be a combination of a liquid crystal epoxy compound and another epoxy compound other than the liquid crystal epoxy compound. Other epoxy compounds include glycidyl ethers of phenolic compounds such as bisphenol A, bisphenol F, bisphenol S, phenol novolak, cresol novolak, resorcinol novolak; glycidyl ethers of alcohol compounds such as butanediol, polyethylene glycol, and polypropylene glycol; phthalic acid Glycidyl esters of carboxylic acid compounds such as isophthalic acid and tetrahydrophthalic acid; glycidyl type (including methyl glycidyl type) epoxy compounds such as those in which active hydrogen bonded to a nitrogen atom such as aniline or isocyanuric acid is substituted with a glycidyl group; Vinylcyclohexene epoxide obtained by epoxidation of olefin bond in the molecule, 3,4-epoxycyclohexylmethyl-3,4-epoxy Hexacarboxylate, alicyclic epoxy compound such as 2- (3,4-epoxy) cyclohexyl-5,5-spiro (3,4-epoxy) cyclohexane-m-dioxane; epoxidized product of bis (4-hydroxy) thioether Glycidyl such as paraxylylene modified phenolic resin, metaxylylene paraxylylene modified phenolic resin, terpene modified phenolic resin, dicyclopentadiene modified phenolic resin, cyclopentadiene modified phenolic resin, polycyclic aromatic ring modified phenolic resin, naphthalene ring containing phenolic resin, etc. Ethers; stilbene type epoxy compounds; halogenated phenol novolac type epoxy compounds (excluding liquid crystal epoxy compounds among these). Other epoxy compounds may be used alone or in combination of two or more.
　その他のエポキシ化合物の含有量は特に制限されず、質量基準において、液晶性エポキシ化合物を１とした場合に、０．３以下であることが好ましく、０．２以下であることがより好ましく、０．１以下であることがさらに好ましい。 The content of other epoxy compounds is not particularly limited, and is preferably 0.3 or less, more preferably 0.2 or less when the liquid crystalline epoxy compound is 1 on a mass basis, 0 More preferably, it is 1 or less.
（硬化剤）
　エポキシ樹脂組成物は、硬化剤を含有する。硬化剤は、エポキシ化合物と硬化反応を生じることができる化合物であれば、特に制限されない。硬化剤の具体例としては、アミン硬化剤、酸無水物硬化剤、フェノール硬化剤、ポリメルカプタン硬化剤、ポリアミノアミド硬化剤、イソシアネート硬化剤、ブロックイソシアネート硬化剤等が挙げられる。硬化剤は、１種のみでも２種以上であってもよい。 (Curing agent)
The epoxy resin composition contains a curing agent. The curing agent is not particularly limited as long as it is a compound capable of causing a curing reaction with the epoxy compound. Specific examples of the curing agent include amine curing agents, acid anhydride curing agents, phenol curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, and blocked isocyanate curing agents. Only one type or two or more types of curing agents may be used.
　エポキシ樹脂組成物の半硬化物又は硬化物の周期構造の形成の観点から、硬化剤としては、アミン硬化剤又はフェノール硬化剤が好ましく、フェノール硬化剤がより好ましく、フェノールノボラック樹脂を含むフェノール硬化剤がさらに好ましい。 From the viewpoint of forming a periodic structure of a semi-cured product or a cured product of the epoxy resin composition, the curing agent is preferably an amine curing agent or a phenol curing agent, more preferably a phenol curing agent, and a phenol curing agent containing a phenol novolac resin. Is more preferable.
　フェノール硬化剤としては、低分子フェノール化合物及びそれらをノボラック化したフェノール樹脂を用いることができる。低分子フェノール化合物としては、フェノール、ｏ－クレゾール、ｍ－クレゾール、ｐ－クレゾール等の単官能フェノール化合物、カテコール、レゾルシノール、ハイドロキノン等の２官能フェノール化合物、１，２，３－トリヒドロキシベンゼン、１，２，４－トリヒドロキシベンゼン、１，３，５－トリヒドロキシベンゼン等の３官能フェノール化合物などが使用可能である。また、これらの低分子フェノール化合物をメチレン鎖等で連結してノボラック化したフェノールノボラック樹脂を硬化剤として用いることもできる。 As the phenol curing agent, low molecular phenol compounds and phenol resins obtained by novolacizing them can be used. Low molecular phenol compounds include monofunctional phenol compounds such as phenol, o-cresol, m-cresol, and p-cresol, bifunctional phenol compounds such as catechol, resorcinol, hydroquinone, 1,2,3-trihydroxybenzene, 1 Trifunctional phenol compounds such as 1,2,4-trihydroxybenzene and 1,3,5-trihydroxybenzene can be used. Further, a phenol novolac resin obtained by connecting these low molecular phenol compounds with a methylene chain or the like to form a novolac can be used as a curing agent.
　硬化剤として用いられるフェノールノボラック樹脂は、モノマーであるフェノール化合物を含んでいてもよい。フェノールノボラック樹脂中のモノマーの含有比率（以下、「モノマー含有比率」ともいう）は、特に制限されない。熱伝導性及び成形性の観点からは、モノマー含有比率は５質量％～８０質量％であることが好ましく、１５質量％～６０質量％であることがより好ましく、２０質量％～５０質量％であることがさらに好ましい。モノマー含有比率が８０質量％以下であると、硬化反応の際に架橋に寄与しないモノマーの量が抑えられ、架橋する高分子量体が多くなるため、より高密度な高次構造が形成され、熱伝導性が向上する傾向にある。また、モノマー含有比率が５質量％以上であると、成形の際に流動し易いため、エポキシ樹脂組成物が無機フィラーを含有する場合には当該フィラーとの密着性がより向上し、より優れた熱伝導性及び耐熱性が達成される傾向にある。 The phenol novolac resin used as the curing agent may contain a phenol compound as a monomer. The monomer content ratio in the phenol novolac resin (hereinafter also referred to as “monomer content ratio”) is not particularly limited. From the viewpoint of thermal conductivity and moldability, the monomer content is preferably 5% by mass to 80% by mass, more preferably 15% by mass to 60% by mass, and 20% by mass to 50% by mass. More preferably it is. When the monomer content is 80% by mass or less, the amount of monomer that does not contribute to crosslinking during the curing reaction is suppressed, and the amount of the high-molecular-weight polymer that is crosslinked increases, so that a higher-density higher-order structure is formed, There is a tendency for conductivity to improve. Further, when the monomer content ratio is 5% by mass or more, it is easy to flow at the time of molding. Therefore, when the epoxy resin composition contains an inorganic filler, the adhesion with the filler is further improved and more excellent. Thermal conductivity and heat resistance tend to be achieved.
　エポキシ樹脂組成物における硬化剤の含有量は、配合する硬化剤の種類及びエポキシ化合物の物性を考慮して適宜設定することができる。
　具体的には、エポキシ化合物におけるエポキシ基の１当量に対して硬化剤の官能基の当量数が０．００５当量～５当量であることが好ましく、０．０１当量～３当量であることがより好ましく、０．５当量～１．５当量であることがさらに好ましい。硬化剤の官能基の当量数がエポキシ基の１当量に対して０．００５当量以上であると、エポキシ化合物の硬化速度をより向上することができる傾向にある。また、硬化剤の官能基の当量数がエポキシ基の１当量に対して５当量以下であると、硬化反応をより適切に制御することができる傾向にある。 Content of the hardening | curing agent in an epoxy resin composition can be suitably set in consideration of the kind of hardening | curing agent to mix | blend and the physical property of an epoxy compound.
Specifically, the number of equivalents of the functional group of the curing agent is preferably 0.005 to 5 equivalents, more preferably 0.01 to 3 equivalents with respect to 1 equivalent of the epoxy group in the epoxy compound. The amount is preferably 0.5 equivalent to 1.5 equivalent. It exists in the tendency which can improve the hardening rate of an epoxy compound more as the equivalent number of the functional group of a hardening | curing agent is 0.005 equivalent or more with respect to 1 equivalent of an epoxy group. Moreover, it exists in the tendency which can control hardening reaction more appropriately that the equivalent number of the functional group of a hardening | curing agent is 5 equivalent or less with respect to 1 equivalent of an epoxy group.
　なお、本明細書中での化学当量は、例えば、硬化剤としてフェノール硬化剤を使用した際は、エポキシ基の１当量に対するフェノール硬化剤の水酸基の当量数を表し、硬化剤としてアミン硬化剤を使用した際は、エポキシ基の１当量に対するアミン硬化剤の活性水素の当量数を表す。 In addition, the chemical equivalent in this specification represents the equivalent number of the hydroxyl group of the phenol curing agent with respect to 1 equivalent of an epoxy group, for example, when a phenol curing agent is used as a curing agent, and an amine curing agent is used as the curing agent. When used, it represents the number of equivalents of active hydrogen in the amine curing agent relative to 1 equivalent of epoxy group.
（硬化促進剤）
　硬化剤として、特にフェノール化合物を用いる場合は、必要に応じて硬化促進剤を併用してもよい。硬化促進剤を併用することで、エポキシ樹脂組成物をさらに充分に硬化させることができる。硬化促進剤の種類は特に制限されず、通常使用される硬化促進剤から選択してよい。硬化促進剤としては、例えば、イミダゾール化合物、ホスフィン化合物、及びボレート塩化合物が挙げられる。 (Curing accelerator)
In particular, when a phenol compound is used as the curing agent, a curing accelerator may be used in combination as necessary. By using a curing accelerator in combination, the epoxy resin composition can be further sufficiently cured. The kind in particular of hardening accelerator is not restrict | limited, You may select from the hardening accelerator normally used. Examples of the curing accelerator include imidazole compounds, phosphine compounds, and borate salt compounds.
（フィラー）
　エポキシ樹脂組成物は、フィラーを含有してもよい。フィラーとしては、熱伝導性と絶縁性の観点から、セラミック粒子を用いることができる。セラミック粒子としては、アルミナ粒子、シリカ粒子、酸化マグネシウム粒子、窒化ホウ素粒子、窒化アルミニウム粒子、窒化ケイ素粒子等が挙げられる。フィラーは、アルミナ粒子、窒化ホウ素粒子、窒化アルミニウム粒子及び酸化マグネシウム粒子からなる群より選択される少なくとも１種を含むことが好ましく、アルミナ粒子を含むことがより好ましい。アルミナ粒子は、結晶性が高いアルミナ粒子を含むことが好ましく、α－アルミナ粒子を含むことがより好ましい。 (Filler)
The epoxy resin composition may contain a filler. As the filler, ceramic particles can be used from the viewpoints of thermal conductivity and insulation. Examples of the ceramic particles include alumina particles, silica particles, magnesium oxide particles, boron nitride particles, aluminum nitride particles, and silicon nitride particles. The filler preferably includes at least one selected from the group consisting of alumina particles, boron nitride particles, aluminum nitride particles, and magnesium oxide particles, and more preferably includes alumina particles. The alumina particles preferably include alumina particles with high crystallinity, and more preferably include α-alumina particles.
　また、フィラーがアルミナ粒子を含む場合、熱伝導性の観点から、アルミナ粒子の表面に対して垂直方向にスメクチック液晶構造の周期構造が形成されていることが好ましい。スメクチック液晶構造の周期構造がアルミナ粒子の表面に対して垂直方向に形成されているか否かは、例えば、上述したようなエポキシ樹脂硬化物の偏光顕微鏡観察により確認できる。 When the filler contains alumina particles, it is preferable that a periodic structure of a smectic liquid crystal structure is formed in a direction perpendicular to the surface of the alumina particles from the viewpoint of thermal conductivity. Whether or not the periodic structure of the smectic liquid crystal structure is formed in the direction perpendicular to the surface of the alumina particles can be confirmed by, for example, observation of the cured epoxy resin as described above with a polarizing microscope.
　フィラーの体積平均粒子径は、熱伝導性の観点から、０．０１μｍ～１ｍｍであることが好ましく、充填性の観点から、０．１０μｍ～１００μｍであることがより好ましい。
　ここで、フィラーの体積平均粒子径は、レーザー回折法を用いて測定される。レーザー回折法による測定は、レーザー回折散乱粒度分布測定装置（例えば、ベックマン・コールター社製、ＬＳ２３０）を用いて行うことができる。レーザー回折散乱粒度分布測定装置を用いて体積累積分布曲線を描いた場合に、小径側からの体積の累積が５０％となる粒子径（Ｄ５０）を、フィラーの体積平均粒子径とする。 The volume average particle diameter of the filler is preferably 0.01 μm to 1 mm from the viewpoint of thermal conductivity, and more preferably 0.10 μm to 100 μm from the viewpoint of filling properties.
Here, the volume average particle diameter of the filler is measured using a laser diffraction method. The measurement by the laser diffraction method can be performed using a laser diffraction scattering particle size distribution measuring device (for example, LS230 manufactured by Beckman Coulter, Inc.). When a volume cumulative distribution curve is drawn using a laser diffraction / scattering particle size distribution measuring apparatus, the particle diameter (D50) at which the cumulative volume from the small diameter side is 50% is defined as the volume average particle diameter of the filler.
　エポキシ樹脂組成物に含まれているフィラーの体積平均粒子径は、エポキシ樹脂組成物からフィラーを抽出した後、レーザー回折散乱粒度分布測定装置を用いて測定される。 The volume average particle diameter of the filler contained in the epoxy resin composition is measured using a laser diffraction / scattering particle size distribution analyzer after extracting the filler from the epoxy resin composition.
　フィラーの抽出と体積平均粒子径の測定は、例えば、有機溶剤、硝酸、王水等を用いてエポキシ樹脂組成物のフィラー以外の成分を溶解したものを、超音波分散機等で充分に分散して分散液を調製し、この分散液を用いて行うことができる。エポキシ樹脂硬化物又は熱伝導フィルムに含まれるフィラーの抽出と体積平均粒子径の測定も、同様にして行うことができる。 The extraction of the filler and the measurement of the volume average particle diameter can be performed by, for example, sufficiently dispersing the components other than the filler of the epoxy resin composition using an organic solvent, nitric acid, aqua regia, etc. with an ultrasonic disperser or the like. A dispersion can be prepared by using the dispersion. The extraction of the filler contained in the cured epoxy resin or the heat conductive film and the measurement of the volume average particle diameter can be performed in the same manner.
　エポキシ樹脂組成物がフィラーを含有する場合、その含有率はエポキシ樹脂組成物の不揮発分全体の２０質量％以下であり、１５質量％以下であることが好ましく、１０質量％以下であることがより好ましい。エポキシ樹脂組成物がフィラーを一定割合以下の量で含有することで、硬さ、柔軟性、流動性等が調整しやすくなる、フィラーが核となってスメクチック液晶構造の成長が促進されるなどの効果が期待できる。 When the epoxy resin composition contains a filler, the content is 20% by mass or less of the entire nonvolatile content of the epoxy resin composition, preferably 15% by mass or less, and more preferably 10% by mass or less. preferable. When the epoxy resin composition contains a filler in an amount of a certain ratio or less, hardness, flexibility, fluidity, etc. can be easily adjusted, and the growth of a smectic liquid crystal structure is promoted by using the filler as a nucleus. The effect can be expected.
　フィラーの含有率がエポキシ樹脂組成物の不揮発分全体の２０質量％以下であることで、エポキシ樹脂組成物の薄膜形成性が良好に維持される。また、エポキシ樹脂組成物を他部材と接触させた状態で硬化させる場合、他部材への接着性が充分に得られる傾向にある。さらに、硬化反応により形成されるスメクチック液晶構造中のドメインがフィラーに衝突しにくくなり、充分に成長して高い熱伝導性が得られる傾向にある。 When the filler content is 20% by mass or less of the entire nonvolatile content of the epoxy resin composition, the thin film formability of the epoxy resin composition is favorably maintained. Moreover, when it hardens | cures in the state which contacted the other member and the epoxy resin composition, it exists in the tendency for the adhesiveness to another member to be fully acquired. Further, the domains in the smectic liquid crystal structure formed by the curing reaction are less likely to collide with the filler and tend to grow sufficiently to obtain high thermal conductivity.
（その他の成分）
　エポキシ樹脂組成物は、さらに、溶剤、カップリング剤、分散剤、エラストマー、離型剤等のその他の成分を含有してもよい。球晶の状態のドメインを形成する観点からは、エポキシ樹脂組成物は溶剤を含有することが好ましい。溶剤の種類は特に制限されず、アセトン、イソブチルアルコール、イソプロピルアルコール、イソペンチルアルコール、ジエチルエーテル、エチレングリコールモノエチルエーテル、キシレン、クレゾール、クロロベンゼン、酢酸イソブチル、酢酸イソプロピル、酢酸イソペンチル、酢酸エチル、酢酸メチル、シクロヘキサノール、シクロヘキサノン、１，４－ジオキサン、ジクロロメタン、スチレン、テトラクロロエチレン、テトラヒドロフラン、トルエン、ｎ－ヘキサン、１－ブタノール、２－ブタノール、メタノール、メチルイソブチルケトン、メチルエチルケトン、メチルシクロヘキサノール、メチルシクロヘキサノン、クロロホルム、四塩化炭素、１，２－ジクロロエタン等の一般的に各種化学製品の製造技術で利用されている有機溶剤の１種又は２種以上を使用することができる。 (Other ingredients)
The epoxy resin composition may further contain other components such as a solvent, a coupling agent, a dispersant, an elastomer, and a release agent. From the viewpoint of forming spherulite domains, the epoxy resin composition preferably contains a solvent. The type of solvent is not particularly limited, and acetone, isobutyl alcohol, isopropyl alcohol, isopentyl alcohol, diethyl ether, ethylene glycol monoethyl ether, xylene, cresol, chlorobenzene, isobutyl acetate, isopropyl acetate, isopentyl acetate, ethyl acetate, methyl acetate , Cyclohexanol, cyclohexanone, 1,4-dioxane, dichloromethane, styrene, tetrachloroethylene, tetrahydrofuran, toluene, n-hexane, 1-butanol, 2-butanol, methanol, methyl isobutyl ketone, methyl ethyl ketone, methyl cyclohexanol, methyl cyclohexanone, chloroform , Carbon tetrachloride, 1,2-dichloroethane, etc. It can be used one or two or more solvents.
（エポキシ樹脂組成物の用途等）
　本実施形態のエポキシ樹脂組成物は、エポキシ化合物の配向性が高く、硬化物としたときの熱伝導性に優れている。従って、本実施形態のエポキシ樹脂組成物は、各種の電気及び電子機器の発熱性の電子部品（例えば、ＩＣ（Ｉｎｔｅｇｒａｔｅｄ　Ｃｉｒｃｕｉｔ）チップ又はプリント配線板）の部材（例えば、放熱材料）に好適に用いることができる。 (Use of epoxy resin composition, etc.)
The epoxy resin composition of the present embodiment has a high orientation of the epoxy compound and is excellent in thermal conductivity when used as a cured product. Therefore, the epoxy resin composition of the present embodiment is suitably used for a member (for example, a heat dissipation material) of a heat-generating electronic component (for example, an IC (Integrated Circuit) chip or a printed wiring board) of various electric and electronic devices. be able to.
＜エポキシ樹脂硬化物の製造方法＞
　本実施形態のエポキシ樹脂硬化物の製造方法は、本実施形態のエポキシ樹脂組成物を熱処理する工程を含み、前記熱処理は下記式を満たす温度Ｘ（℃）で行われる。
　　　　　（Ｂ＋５℃）≦Ｘ≦（Ａ－５℃） <Method for producing cured epoxy resin>
The manufacturing method of the cured epoxy resin of the present embodiment includes a step of heat-treating the epoxy resin composition of the present embodiment, and the heat treatment is performed at a temperature X (° C.) that satisfies the following formula.
(B + 5 ℃) ≦ X ≦ (A-5 ℃)
　式中、Ａは前記エポキシ樹脂組成物がスメクチック液晶構造を形成可能な温度の上限値（℃）であり、Ｂは前記エポキシ樹脂組成物がスメクチック液晶構造を形成可能な温度の下限値（℃）である。なお、ＡとＢはＢ＜Ａ－１０の関係を満たす。 In the formula, A is the upper limit (° C.) of the temperature at which the epoxy resin composition can form a smectic liquid crystal structure, and B is the lower limit (° C.) of the temperature at which the epoxy resin composition can form a smectic liquid crystal structure. It is. A and B satisfy the relationship B <A-10.
　熱処理の温度Ｘは、エポキシ樹脂組成物に含まれる成分の種類、組成比等に応じて設定しうる。例えば、１００℃～２００℃の範囲から選択されることが好ましく、１２０℃～１８０℃の範囲から選択されることがより好ましい。熱処理の温度Ｘは熱処理の開始から終了まで一定であっても、変化してもよい。Ｘが変化する場合、硬化初期段階において上記条件を満たすことが好ましい。また、全熱処理時間の２０％以上においてＸが上記条件を満たすことが好ましい。 The temperature X of the heat treatment can be set according to the type and composition ratio of components contained in the epoxy resin composition. For example, it is preferably selected from the range of 100 ° C. to 200 ° C., more preferably selected from the range of 120 ° C. to 180 ° C. The temperature X of the heat treatment may be constant from the start to the end of the heat treatment or may change. When X changes, it is preferable to satisfy the above conditions in the initial curing stage. Moreover, it is preferable that X satisfies the above-mentioned conditions at 20% or more of the total heat treatment time.
　熱処理の時間は特に制限されず、例えば、５分間～６０分間の範囲から選択されることが好ましく、１０分間～３０分間の範囲から選択されることがより好ましい。 The time for the heat treatment is not particularly limited, and is preferably selected from a range of 5 minutes to 60 minutes, for example, and more preferably selected from a range of 10 minutes to 30 minutes.
　必要に応じ、熱処理後に得られたエポキシ樹脂硬化物に対してさらに別の熱処理（以下、「後硬化処理」ともいう）を行ってもよい。エポキシ樹脂硬化物に対して後硬化処理を行うことで、架橋密度がより高まる傾向にある。後硬化処理は１回のみ実施しても、２回以上実施してもよい。 If necessary, the epoxy resin cured product obtained after the heat treatment may be further subjected to another heat treatment (hereinafter also referred to as “post-curing treatment”). By performing post-curing treatment on the cured epoxy resin, the crosslinking density tends to increase. The post-curing treatment may be performed only once or twice or more.
　後硬化処理の温度は特に制限されず、例えば、１４０℃～２４０℃の範囲から選択されることが好ましく、１６０℃～２２０℃の範囲から選択されることがより好ましい。後硬化処理の温度は熱処理の開始から終了まで一定であっても、変化してもよい。 The temperature of the post-curing treatment is not particularly limited, and is preferably selected from the range of 140 ° C. to 240 ° C., for example, and more preferably selected from the range of 160 ° C. to 220 ° C. The temperature of the post-curing treatment may be constant from the start to the end of the heat treatment or may vary.
　後硬化処理の時間は特に制限はなく、例えば、１０分間～６００分間の範囲から選択されることが好ましく、６０分間～３００分間の範囲から選択されることがより好ましい。 The time for the post-curing treatment is not particularly limited, and is preferably selected from a range of, for example, 10 minutes to 600 minutes, and more preferably selected from a range of 60 minutes to 300 minutes.
　後硬化に用いる加熱装置は特に制限はなく、一般的に用いられる加熱装置を用いることができる。 The heating device used for post-curing is not particularly limited, and a commonly used heating device can be used.
　エポキシ樹脂硬化物の製造方法は、エポキシ樹脂組成物がフィルムの状態で熱処理を行ってもよい。こうすることで、エポキシ樹脂硬化物のフィルム状物である本実施形態の熱伝導フィルムを製造することができる。 In the method for producing a cured epoxy resin, the epoxy resin composition may be heat-treated in a film state. By carrying out like this, the heat conductive film of this embodiment which is a film-form material of an epoxy resin hardened | cured material can be manufactured.
＜エポキシ樹脂硬化物及び熱伝導フィルム＞
　本実施形態のエポキシ樹脂硬化物は、本実施形態のエポキシ樹脂組成物の硬化物である。本実施形態の熱伝導フィルムは、本実施形態のエポキシ樹脂硬化物のフィルム状物である。 <Hardened epoxy resin and heat conductive film>
The cured epoxy resin of the present embodiment is a cured product of the epoxy resin composition of the present embodiment. The heat conductive film of this embodiment is a film-like product of the cured epoxy resin of this embodiment.
　本実施形態のエポキシ樹脂硬化物及び熱伝導フィルムは、本実施形態のエポキシ樹脂組成物を硬化して得られるものであるため、薄膜形成性に優れ、熱伝導性に優れている。 Since the cured epoxy resin and the heat conductive film of the present embodiment are obtained by curing the epoxy resin composition of the present embodiment, the thin film formability is excellent and the heat conductivity is excellent.
　本実施形態のエポキシ樹脂硬化物及び熱伝導フィルムは、スメクチック液晶構造の周期構造が形成されている。熱伝導性の観点からは、スメクチック液晶構造の周期構造の周期長が２．０ｎｍ～４．０ｎｍであることが好ましく、２．０ｎｍ～３．０ｎｍであることがより好ましい。 In the cured epoxy resin and the heat conductive film of this embodiment, a periodic structure having a smectic liquid crystal structure is formed. From the viewpoint of thermal conductivity, the periodic length of the periodic structure of the smectic liquid crystal structure is preferably 2.0 nm to 4.0 nm, and more preferably 2.0 nm to 3.0 nm.
　熱伝導フィルムは、エポキシ樹脂組成物がフィルムの形状に成形された状態で熱処理を行って作製することが好ましい。熱伝導フィルムの平均厚さは特に制限されず、例えば、０．０１ｍｍ～３ｍｍの範囲から選択できる。 The heat conductive film is preferably prepared by performing a heat treatment in a state where the epoxy resin composition is formed into a film shape. The average thickness of the heat conductive film is not particularly limited, and can be selected from a range of 0.01 mm to 3 mm, for example.
　以下、本実施形態を実施例により具体的に説明するが、本実施形態はこれらの実施例に限定されるものではない。 Hereinafter, the present embodiment will be specifically described by way of examples, but the present embodiment is not limited to these examples.
＜実施例１＞
（１）エポキシ化合物のプレポリマーの合成
　メソゲン構造を有するエポキシ化合物（４－｛４－（２，３－エポキシプロポキシ）フェニル｝シクロヘキシル＝４－（２，３－エポキシプロポキシ）ベンゾエート、一般式（Ｉ）で表される化合物）（以下、エポキシ化合物１とも称する）と、プレポリマー化剤としてハイドロキノンを、モル比（エポキシ化合物１／ハイドロキノン）が１０／１．３となるように反応させて、プレポリマー（以下、エポキシ化合物２とも称する）を合成した。 <Example 1>
(1) Synthesis of prepolymer of epoxy compound Epoxy compound having mesogenic structure (4- {4- (2,3-epoxypropoxy) phenyl} cyclohexyl = 4- (2,3-epoxypropoxy) benzoate, general formula (I ) (Hereinafter also referred to as epoxy compound 1) and hydroquinone as a prepolymerizing agent are reacted so that the molar ratio (epoxy compound 1 / hydroquinone) is 10 / 1.3. A polymer (hereinafter also referred to as epoxy compound 2) was synthesized.
（２）硬化剤（フェノールノボラック樹脂）の合成
　窒素置換したセパラブルフラスコに、フェノール化合物としてレゾルシノール１０５ｇ（０．９５ｍｏｌ）及びカテコール５ｇ（０．０５ｍｏｌ）と、触媒としてシュウ酸０．１１ｇ（フェノール化合物に対して０．１質量％）と、溶剤としてメタノール１５ｇと、を量り取った後、内容物を撹拌し、４０℃以下になるように油浴で冷却しながらホルマリン３０ｇ（約０．３３ｍｏｌ、ホルマリン（Ｐ）とフェノール化合物（Ｆ）とのモル比：Ｐ／Ｆ＝０．３３）を加えた。２時間撹拌した後、油浴を１００℃になるように加温しながら水及びメタノールを減圧留去した。水及びメタノールが留出しなくなったことを確認した後、フェノールノボラック樹脂が５０質量％となるようにシクロヘキサノンを加え、フェノールノボラック樹脂溶液（以下、硬化剤１とも称する）を得た。
　ゲルパーミエーションクロマトグラフィー（ＧＰＣ）による分子量測定で、得られたフェノールノボラック樹脂の数平均分子量は４８４、構造単位数ｎは平均で３．９であった。また、モノマー含有比率は４０質量％であった。
　１Ｈ－ＮＭＲの測定により、フェノールノボラック樹脂の構造単位１個（フェノール化合物１分子に相当）あたりに水酸基が平均で２．１個含まれることが分かった。水酸基当量は６２ｇ／ｅｑであった。 (2) Synthesis of curing agent (phenol novolac resin) In a nitrogen-substituted separable flask, 105 g (0.95 mol) of resorcinol and 5 g (0.05 mol) of catechol as a phenol compound and 0.11 g of oxalic acid (phenol compound) as a catalyst 0.1% by mass) and 15 g of methanol as a solvent, the contents were stirred, and 30 g of formalin (about 0.33 mol, about 0.33 mol, while being cooled in an oil bath to 40 ° C. or lower) A molar ratio of formalin (P) to phenolic compound (F): P / F = 0.33) was added. After stirring for 2 hours, water and methanol were distilled off under reduced pressure while heating the oil bath to 100 ° C. After confirming that water and methanol were no longer distilled, cyclohexanone was added so that the phenol novolak resin was 50% by mass to obtain a phenol novolac resin solution (hereinafter also referred to as curing agent 1).
In the molecular weight measurement by gel permeation chromatography (GPC), the number average molecular weight of the obtained phenol novolak resin was 484, and the number of structural units n was 3.9 on average. The monomer content ratio was 40% by mass.
From 1 H-NMR measurement, it was found that an average of 2.1 hydroxyl groups were contained per structural unit of phenol novolac resin (corresponding to 1 molecule of phenol compound). The hydroxyl equivalent was 62 g / eq.
（３）エポキシ樹脂組成物の調製
　エポキシ化合物２と、硬化剤１と、硬化促進剤としてのトリフェニルホスフィンと、を混合して、エポキシ樹脂組成物を調製した。
　エポキシ化合物２と硬化剤１の配合量は、エポキシ化合物２のエポキシ基の当量数に対する硬化剤１の水酸基の当量数の比（エポキシ基：水酸基）が、１：１となるように調整した。硬化促進剤の配合量は、エポキシ化合物２と硬化剤の合計質量に対して、０．８質量％となる量にした。　 (3) Preparation of epoxy resin composition Epoxy compound 2, curing agent 1, and triphenylphosphine as a curing accelerator were mixed to prepare an epoxy resin composition.
The compounding quantity of the epoxy compound 2 and the hardening | curing agent 1 was adjusted so that ratio of the equivalent number of the hydroxyl group of the hardening | curing agent 1 with respect to the equivalent number of the epoxy group of the epoxy compound 2 (epoxy group: hydroxyl group) might be set to 1: 1. The compounding amount of the curing accelerator was set to 0.8% by mass with respect to the total mass of the epoxy compound 2 and the curing agent.
（４）熱伝導フィルムの作製
　調製したエポキシ樹脂組成物を、すり鉢とすり棒を用いて、室温（２５℃）で３０分間混練した。その後、１４０℃で溶融させながら、平均厚さが５０μｍのフィルム状に成形した。次いで、１４０℃で３０分間の熱処理を行ってエポキシ樹脂組成物を硬化させて、熱伝導フィルムを作製した。 (4) Preparation of heat conductive film The prepared epoxy resin composition was kneaded for 30 minutes at room temperature (25 ° C) using a mortar and a mortar. Then, it was formed into a film having an average thickness of 50 μm while being melted at 140 ° C. Next, heat treatment was performed at 140 ° C. for 30 minutes to cure the epoxy resin composition, and a heat conductive film was produced.
　熱処理の間の硬化反応に伴う相変化の様子を、熱処理の途中で複数回エポキシ樹脂組成物を取り出し、偏光顕微鏡で観察することにより調べた。その結果、等方構造（Ｉｓｏ）、ネマチック液晶構造（Ｎ）、スメクチック液晶構造（Ｓｍ）の順に変化していた。
　実施例１についてはさらに、温度を変更して複数回の熱処理を行い、上記と同様にして相変化の様子を調べた。その結果、図１に示すパターンの相図が得られた。 The state of the phase change accompanying the curing reaction during the heat treatment was examined by taking out the epoxy resin composition a plurality of times during the heat treatment and observing with a polarizing microscope. As a result, the structure changed in the order of isotropic structure (Iso), nematic liquid crystal structure (N), and smectic liquid crystal structure (Sm).
For Example 1, the temperature was changed and heat treatment was performed a plurality of times, and the state of phase change was examined in the same manner as described above. As a result, a phase diagram of the pattern shown in FIG. 1 was obtained.
（５）周期構造の評価
　作製した熱伝導フィルムの周期構造に由来する回折角度を、広角Ｘ線回折装置（株式会社リガク製、「ＲＩＮＴ２５００ＨＬ」）を使用して測定した。次いで、測定された回折角度をブラッグの式により換算して、周期長を求めた。結果を表１に示す。 (5) Evaluation of periodic structure The diffraction angle derived from the periodic structure of the produced heat conductive film was measured using a wide-angle X-ray diffractometer (manufactured by Rigaku Corporation, “RINT2500HL”). Next, the measured diffraction angle was converted according to the Bragg equation to obtain the period length. The results are shown in Table 1.
　Ｘ線回折は、上述した測定条件により行った。測定された回折角度２θは３．２°であり、スメクチック液晶構造の周期構造が形成されていることが確認された。また、測定された回折角度をブラッグの式により換算して得られた周期長は２．７（ｎｍ）であった。 X-ray diffraction was performed under the measurement conditions described above. The measured diffraction angle 2θ was 3.2 °, and it was confirmed that a periodic structure of a smectic liquid crystal structure was formed. Moreover, the period length obtained by converting the measured diffraction angle by the Bragg equation was 2.7 (nm).
（６）ドメイン径の測定
　作製した熱伝導フィルムの表面を、偏光顕微鏡（株式会社ニコン製、製品名：「ＯＰＴＩＰＨＯＴ２－ＰＯＬ」）により観察した。その結果、スメクチック液晶構造のドメインが複数観察された。観察されたドメインのうち、任意に選択した１０個のドメインについて直径の測定を行い、その算術平均値を求めたところ７０μｍであった。ドメインの直径の測定は、上述した条件で行った。 (6) Measurement of domain diameter The surface of the produced heat conductive film was observed with a polarizing microscope (manufactured by Nikon Corporation, product name: “OPTIPHOT2-POL”). As a result, a plurality of domains having a smectic liquid crystal structure were observed. Among the observed domains, the diameter of ten arbitrarily selected domains was measured, and the arithmetic average value thereof was found to be 70 μm. The measurement of the diameter of the domain was performed under the conditions described above.
（７）熱伝導性の評価
　作製した熱伝導フィルムを１ｃｍ角の正方形に切出し、熱拡散率を測定するための試験片とした。フラッシュ法装置（ＮＥＴＺＳＣＨ社製、「ＮａｎｏＦｌａｓｈ　ＬＦＡ４４７」）を用いて、試験片の熱拡散率を測定した。測定結果にアルキメデス法により測定した密度と、ＤＳＣ法により測定した比熱とを乗じることにより、熱伝導フィルムの厚さ方向の熱伝導率を求めたところ、０．８Ｗ／（ｍ・Ｋ）であった。 (7) Evaluation of thermal conductivity The produced thermal conductive film was cut into a 1 cm square and used as a test piece for measuring thermal diffusivity. The thermal diffusivity of the test piece was measured using a flash method apparatus (“NanoFlash LFA447” manufactured by NETZSCH). By multiplying the measurement result by the density measured by the Archimedes method and the specific heat measured by the DSC method, the thermal conductivity in the thickness direction of the heat conductive film was obtained and found to be 0.8 W / (m · K). It was.
（実施例２、３）
　実施例１において、アルミナ粒子（新日鉄住金マテリアルズ株式会社　マイクロンカンパニー製、商品名：「ＡＸ３－３２」、体積平均粒子径：４μｍ、以下の実施例及び比較例において同じ）を、エポキシ樹脂組成物の不揮発分全体に対する含有率がそれぞれ５質量％、１０質量％となるように配合したこと以外は実施例１と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Examples 2 and 3)
In Example 1, alumina particles (manufactured by Nippon Steel & Sumikin Materials Co., Ltd., Micron Company, trade name: “AX3-32”, volume average particle size: 4 μm, the same in the following Examples and Comparative Examples) were used as epoxy resin compositions. An epoxy resin composition was prepared in the same manner as in Example 1 except that the content was 5% by mass and 10% by mass with respect to the whole nonvolatile content, and a heat conductive film was produced. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
（実施例４）
　実施例１において、エポキシ化合物２の代わりに、エポキシ化合物１を用いたこと以外は実施例１と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 Example 4
In Example 1, an epoxy resin composition was prepared in the same manner as in Example 1 except that the epoxy compound 1 was used instead of the epoxy compound 2, and a heat conductive film was produced. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
　エポキシ化合物１と硬化剤１の配合量は、エポキシ化合物１のエポキシ基の当量数に対する硬化剤１の水酸基の当量数の比（エポキシ基：水酸基）が、１：１となるように調整した。硬化促進剤の配合量は、エポキシ化合物１と硬化剤１の合計質量に対して、０．８質量％となる量にした。 The blending amount of the epoxy compound 1 and the curing agent 1 was adjusted so that the ratio of the number of equivalents of the hydroxyl group of the curing agent 1 to the number of equivalents of the epoxy group of the epoxy compound 1 (epoxy group: hydroxyl group) was 1: 1. The blending amount of the curing accelerator was set to 0.8% by mass with respect to the total mass of the epoxy compound 1 and the curing agent 1.
（実施例５、６）
　実施例４において、アルミナ粒子を、エポキシ樹脂組成物の不揮発分全体に対する含有率がそれぞれ５質量％、１０質量％となるように配合したこと以外は実施例４と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Examples 5 and 6)
In Example 4, the epoxy resin composition was prepared in the same manner as in Example 4 except that the alumina particles were blended so that the content of the epoxy resin composition was 5% by mass and 10% by mass, respectively, with respect to the entire nonvolatile content. To prepare a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
（実施例７）
　実施例１において、エポキシ化合物２の代わりに、メソゲン構造を有するエポキシ化合物（１－（３－メチル－４－オキシラニメトキシフェニル）－４－（オキシラニルメトキシフェニル）－１－シクロヘキセン）（以下、エポキシ化合物３とも称する）を用いたこと以外は実施例１と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Example 7)
In Example 1, instead of the epoxy compound 2, an epoxy compound having a mesogenic structure (1- (3-methyl-4-oxiranimethoxyphenyl) -4- (oxiranylmethoxyphenyl) -1-cyclohexene) (hereinafter referred to as “epoxy compound 2”) The epoxy resin composition was prepared in the same manner as in Example 1 except that epoxy compound 3 was also used, and a heat conductive film was produced. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
　エポキシ化合物３と硬化剤１の配合量は、エポキシ化合物３のエポキシ基の当量数に対する硬化剤１の水酸基の当量数の比（エポキシ基：水酸基）が、１：１となるように調整した。硬化促進剤の配合量は、エポキシ化合物３と硬化剤１の合計質量に対して、０．８質量％となる量にした。　 The compounding amount of the epoxy compound 3 and the curing agent 1 was adjusted such that the ratio of the number of equivalents of the hydroxyl group of the curing agent 1 to the number of equivalents of the epoxy group of the epoxy compound 3 (epoxy group: hydroxyl group) was 1: 1. The blending amount of the curing accelerator was set to 0.8% by mass with respect to the total mass of the epoxy compound 3 and the curing agent 1. *
（実施例８、９）
　実施例７において、アルミナ粒子を、エポキシ樹脂組成物の不揮発分全体に対する含有率がそれぞれ５質量％、１０質量％となるように配合したこと以外は実施例７と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Examples 8 and 9)
In Example 7, the epoxy resin composition was the same as Example 7 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5% by mass and 10% by mass, respectively. To prepare a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
（実施例１０）
　実施例７において、硬化剤１の代わりに、１，５－ジアミノナフタレン（以下、硬化剤２とも称する）を用いたことと、硬化促進剤を省いたこと以外は実施例７と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Example 10)
In Example 7, instead of curing agent 1, 1,5-diaminonaphthalene (hereinafter also referred to as curing agent 2) was used, and in the same manner as in Example 7, except that the curing accelerator was omitted. An epoxy resin composition was prepared to produce a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
　エポキシ化合物３と硬化剤２の配合量は、エポキシ化合物３のエポキシ基の当量数に対する硬化剤２のアミノ基の当量数の比（エポキシ基：アミノ基）が、１：１となるように調整した。 The blending amount of the epoxy compound 3 and the curing agent 2 is adjusted so that the ratio of the number of equivalents of the amino group of the curing agent 2 to the number of equivalents of the epoxy group of the epoxy compound 3 (epoxy group: amino group) is 1: 1. did.
（実施例１１、１２）
　実施例１０において、アルミナ粒子を、エポキシ樹脂組成物の不揮発分全体に対する含有率がそれぞれ５質量％、１０質量％となるように配合したこと以外は実施例１０と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Examples 11 and 12)
In Example 10, the epoxy resin composition was the same as Example 10 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5 mass% and 10 mass%, respectively. To prepare a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
（実施例１３）
　実施例１において、溶剤としてメチルエチルケトン（ＭＥＫ）５ｇをさらに加えてエポキシ樹脂組成物を調製した。調製したエポキシ樹脂組成物を、ミックスローラーを用いて、室温（２５℃）で３０分間撹拌した。その後に室温で、フィルム状に成形した。次いで、１４０℃で３０分間の熱処理を行って、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Example 13)
In Example 1, 5 g of methyl ethyl ketone (MEK) was further added as a solvent to prepare an epoxy resin composition. The prepared epoxy resin composition was stirred for 30 minutes at room temperature (25 ° C.) using a mix roller. Thereafter, it was formed into a film at room temperature. Next, heat treatment was performed at 140 ° C. for 30 minutes to produce a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
（実施例１４、１５）
　実施例１３において、アルミナ粒子を、エポキシ樹脂組成物の不揮発分全体に対する含有率がそれぞれ５質量％、１０質量％となるように配合したこと以外は実施例１３と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Examples 14 and 15)
In Example 13, the epoxy resin composition was prepared in the same manner as in Example 13 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5 mass% and 10 mass%, respectively. To prepare a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
（比較例１）
　実施例１において、エポキシ化合物１の代わりに、メソゲン構造を有しないエポキシ化合物であるビスフェノールＡ型エポキシ化合物（三菱化学株式会社製、商品名：「ｊＥＲ８２８」、以下「エポキシ化合物４」ともいう）を用いたこと以外は実施例１と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Comparative Example 1)
In Example 1, in place of the epoxy compound 1, a bisphenol A type epoxy compound (trade name: “jER828”, hereinafter also referred to as “epoxy compound 4” manufactured by Mitsubishi Chemical Corporation), which is an epoxy compound having no mesogen structure, is used. Except having used, it carried out similarly to Example 1, and prepared the epoxy resin composition, and produced the heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
　エポキシ化合物４と硬化剤１の配合量は、エポキシ化合物４のエポキシ基の当量数に対する硬化剤１の水酸基の当量数の比（エポキシ基：水酸基）が、１：１となるように調整した。硬化促進剤の配合量は、エポキシ化合物４と硬化剤１の合計質量に対して、０．８質量％となる量にした。　 The compounding amount of the epoxy compound 4 and the curing agent 1 was adjusted so that the ratio of the number of equivalents of the hydroxyl group of the curing agent 1 to the number of equivalents of the epoxy group of the epoxy compound 4 (epoxy group: hydroxyl group) was 1: 1. The blending amount of the curing accelerator was set to 0.8% by mass with respect to the total mass of the epoxy compound 4 and the curing agent 1. *
（比較例２、３）
　比較例１において、アルミナ粒子を、エポキシ樹脂組成物の不揮発分全体に対する含有率がそれぞれ５質量％、１０質量％となるように配合したこと以外は比較例１と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Comparative Examples 2 and 3)
In Comparative Example 1, the epoxy resin composition was prepared in the same manner as in Comparative Example 1 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5 mass% and 10 mass%, respectively. To prepare a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
（比較例４）
　実施例１０において、エポキシ化合物３の代わりに、エポキシ化合物４を用いたこと以外は実施例１と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Comparative Example 4)
In Example 10, an epoxy resin composition was prepared in the same manner as in Example 1 except that the epoxy compound 4 was used instead of the epoxy compound 3, and a heat conductive film was produced. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
　エポキシ化合物４と硬化剤２の配合量は、エポキシ化合物４のエポキシ基の当量数に対する硬化剤２のアミノ基の当量数の比（エポキシ基：アミノ基）が、１：１となるように調整した。 The compounding amount of the epoxy compound 4 and the curing agent 2 is adjusted so that the ratio of the number of equivalents of the amino group of the curing agent 2 to the number of equivalents of the epoxy group of the epoxy compound 4 (epoxy group: amino group) is 1: 1. did.
（比較例５、６）
　比較例４において、アルミナ粒子を、エポキシ樹脂組成物の不揮発分全体に対する含有率がそれぞれ５質量％、１０質量％となるように配合したこと以外は比較例４と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Comparative Examples 5 and 6)
In Comparative Example 4, the epoxy resin composition was the same as Comparative Example 4 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5 mass% and 10 mass%, respectively. To prepare a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
（比較例７）
　実施例１３において、エポキシ化合物２の代わりに、エポキシ化合物４を用いたこと以外は実施例１３と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Comparative Example 7)
In Example 13, an epoxy resin composition was prepared in the same manner as in Example 13 except that the epoxy compound 4 was used instead of the epoxy compound 2, and a heat conductive film was produced. Then, in the same manner as in Example 1, the periodic length, domain diameter, and thermal conductivity of the periodic structure were obtained. The results are shown in Table 1.
　エポキシ化合物４と硬化剤１の配合量は、エポキシ化合物４のエポキシ基の当量数に対する硬化剤１の水酸基の当量数の比（エポキシ基：水酸基）が、１：１となるように調整した。硬化促進剤の配合量は、エポキシ化合物４と硬化剤１の合計質量に対して、０．８質量％となる量にした。 The compounding amount of the epoxy compound 4 and the curing agent 1 was adjusted so that the ratio of the number of equivalents of the hydroxyl group of the curing agent 1 to the number of equivalents of the epoxy group of the epoxy compound 4 (epoxy group: hydroxyl group) was 1: 1. The blending amount of the curing accelerator was set to 0.8% by mass with respect to the total mass of the epoxy compound 4 and the curing agent 1.
（比較例８、９）
　比較例７において、アルミナ粒子を、エポキシ樹脂組成物の不揮発分全体に対する含有率がそれぞれ５質量％、１０質量％となるように配合したこと以外は比較例７と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Comparative Examples 8 and 9)
In Comparative Example 7, the epoxy resin composition was the same as Comparative Example 7 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 5% by mass and 10% by mass, respectively. To prepare a heat conductive film. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
（比較例１０）
　実施例１において、アルミナ粒子を、エポキシ樹脂組成物の不揮発分全体に対する含有率が５０質量％となるように配合したこと以外は実施例１と同様にして、エポキシ樹脂組成物を調製し、熱伝導フィルムを作製した。そして、実施例１と同様にして、相変化の様子、周期構造の周期長、ドメイン径及び熱伝導率を求めた。結果を表１に示す。 (Comparative Example 10)
In Example 1, an epoxy resin composition was prepared in the same manner as in Example 1 except that the alumina particles were blended so that the content of the epoxy resin composition with respect to the entire nonvolatile content was 50% by mass. A conductive film was prepared. In the same manner as in Example 1, the state of phase change, the period length of the periodic structure, the domain diameter, and the thermal conductivity were obtained. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000004
 
 
Figure JPOXMLDOC01-appb-T000004
 
 
　表１中の溶剤の欄の「－」は、溶剤を使用していないことを表す。
　表１中の周期構造の欄の「－」は、その欄に該当する熱伝導フィルムにおいて周期構造が形成されていないことを表す。
　表１中のドメイン径の欄の「－」は、その欄に該当する熱伝導フィルムにおいてドメインが形成されていないことを表す。
　表１中の熱伝導率の欄の「－」は、その欄に該当する熱伝導フィルムを作製できなかったことを表す。 “-” In the column of solvent in Table 1 indicates that no solvent is used.
“-” In the column of the periodic structure in Table 1 indicates that the periodic structure is not formed in the heat conductive film corresponding to the column.
“-” In the domain diameter column in Table 1 indicates that no domain is formed in the heat conductive film corresponding to the column.
“-” In the column of thermal conductivity in Table 1 indicates that the thermal conductive film corresponding to that column could not be produced.
　表１に示されるように、比較例１～９で作製した熱伝導フィルムは、実施例で作製した熱伝導フィルムに比べて熱伝導率が低かった。この理由としては、実施例で作製した熱伝導フィルムではスメクチック液晶構造のドメインが形成されているのに対し、比較例で作製した熱伝導フィルムではスメクチック液晶構造のドメインが形成されていないことが考えられる。
　アルミナ粒子の含有率が２０質量％を超える比較例１０で作製した熱伝導フィルムは、スメクチック液晶構造のドメインが形成されていたが、ドメイン径は実施例１～１５よりも小さかった。これは、ドメインの成長がアルミナ粒子に衝突して停止する割合が、実施例に比べて大きかったためと考えられる。また、平均厚さが５０μｍの熱伝導フィルムを形成することができなかった。 As shown in Table 1, the thermal conductivity films produced in Comparative Examples 1 to 9 had lower thermal conductivity than the thermal conduction films produced in Examples. This is because the smectic liquid crystal domain is formed in the heat conduction film produced in the example, whereas the smectic liquid crystal structure domain is not formed in the heat conduction film produced in the comparative example. It is done.
The heat conductive film produced in Comparative Example 10 in which the content of alumina particles exceeded 20 mass% had smectic liquid crystal structure domains formed, but the domain diameter was smaller than those in Examples 1-15. This is presumably because the rate at which the domain growth collides with the alumina particles and stops is larger than in the example. Moreover, a heat conductive film having an average thickness of 50 μm could not be formed.

Claims (16)

  1. 　エポキシ化合物と、硬化剤とを含み、スメクチック液晶構造を形成可能な反応誘起型のエポキシ樹脂組成物であり、フィラーを含まないか、フィラーの含有率が前記エポキシ樹脂組成物の不揮発分全体の２０質量％以下であるエポキシ樹脂組成物。 A reaction-induced epoxy resin composition that includes an epoxy compound and a curing agent and can form a smectic liquid crystal structure, and does not contain a filler, or the filler content is 20% of the total nonvolatile content of the epoxy resin composition. An epoxy resin composition having a mass% or less.
  2. 　前記スメクチック液晶構造はドメインを形成しており、前記ドメインの直径の平均値が２０μｍ以上である、請求項１に記載のエポキシ樹脂組成物。 2. The epoxy resin composition according to claim 1, wherein the smectic liquid crystal structure forms a domain, and an average value of the diameter of the domain is 20 μm or more.
  3. 　前記スメクチック液晶構造はドメインを形成しており、前記ドメインは球晶を含む、請求項１又は請求項２に記載のエポキシ樹脂組成物。 The epoxy resin composition according to claim 1 or 2, wherein the smectic liquid crystal structure forms a domain, and the domain includes a spherulite.
  4. 　前記スメクチック液晶構造はネマチック液晶構造を経由して形成される、請求項１～請求項３のいずれか１項に記載のエポキシ樹脂組成物。 4. The epoxy resin composition according to claim 1, wherein the smectic liquid crystal structure is formed via a nematic liquid crystal structure.
  5. 　１３０℃～１６０℃の範囲から選択されるいずれの硬化温度においてもスメクチック液晶構造を形成可能である、請求項１～請求項４のいずれか１項に記載のエポキシ樹脂組成物。 The epoxy resin composition according to any one of claims 1 to 4, wherein the smectic liquid crystal structure can be formed at any curing temperature selected from a range of 130 ° C to 160 ° C.
  6. 　１６０℃の硬化温度において３分以内にスメクチック液晶構造を形成可能である、請求項１～請求項５のいずれか１項に記載のエポキシ樹脂組成物。 The epoxy resin composition according to any one of claims 1 to 5, wherein a smectic liquid crystal structure can be formed within 3 minutes at a curing temperature of 160 ° C.
  7. 　前記エポキシ化合物がメソゲン構造を有するエポキシ化合物を含む、請求項１～請求項６のいずれか１項に記載のエポキシ樹脂組成物。 The epoxy resin composition according to any one of claims 1 to 6, wherein the epoxy compound contains an epoxy compound having a mesogenic structure.
  8. 　前記エポキシ化合物が下記一般式（Ｉ）で表される化合物を含む、請求項１～請求項７のいずれか１項に記載のエポキシ樹脂組成物。
    Figure JPOXMLDOC01-appb-C000001
     
    〔一般式（Ｉ）中、Ｒ１～Ｒ４はそれぞれ独立に、水素原子又は炭素数１～３のアルキル基を示す。〕     The epoxy resin composition according to any one of claims 1 to 7, wherein the epoxy compound comprises a compound represented by the following general formula (I).
    Figure JPOXMLDOC01-appb-C000001

    [In general formula (I), R 1 to R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ]
  9. 　前記エポキシ化合物が前記一般式（Ｉ）で表される化合物と２価フェノール化合物との反応生成物を含む、請求項８に記載のエポキシ樹脂組成物。 The epoxy resin composition according to claim 8, wherein the epoxy compound includes a reaction product of the compound represented by the general formula (I) and a divalent phenol compound.
  10. 　前記硬化剤がフェノールノボラック樹脂を含む、請求項１～請求項９のいずれか１項に記載のエポキシ樹脂組成物。 The epoxy resin composition according to any one of claims 1 to 9, wherein the curing agent comprises a phenol novolac resin.
  11. 　前記フィラーがシリカ粒子、アルミナ粒子、酸化マグネシウム粒子、窒化アルミニウム粒子及び窒化ホウ素粒子からなる群より選択される少なくとも１種を含む、請求項１～請求項１０のいずれか１項に記載のエポキシ樹脂組成物。 The epoxy resin according to any one of claims 1 to 10, wherein the filler includes at least one selected from the group consisting of silica particles, alumina particles, magnesium oxide particles, aluminum nitride particles, and boron nitride particles. Composition.
  12. 　請求項１～請求項１１のいずれか１項に記載のエポキシ樹脂組成物の硬化物である、エポキシ樹脂硬化物。 An epoxy resin cured product, which is a cured product of the epoxy resin composition according to any one of claims 1 to 11.
  13. 　スメクチック液晶構造の周期構造を有し、前記周期構造の周期長が１．０ｎｍ～４．０ｎｍである、請求項１２に記載のエポキシ樹脂硬化物。 The cured epoxy resin product according to claim 12, having a periodic structure of a smectic liquid crystal structure, wherein the periodic length of the periodic structure is 1.0 nm to 4.0 nm.
  14. 　請求項１２又は請求項１３に記載のエポキシ樹脂硬化物のフィルム状物である、熱伝導フィルム。 A heat conductive film, which is a film-like product of the cured epoxy resin according to claim 12 or 13.
  15. 　請求項１～請求項１１のいずれか１項に記載のエポキシ樹脂組成物を熱処理する工程を含み、前記熱処理は下記式を満たす温度Ｘ（℃）で行われる、エポキシ樹脂硬化物の製造方法。
    　　　　　（Ｂ＋５℃）≦Ｘ≦（Ａ－５℃）
    〔式中、Ａは前記エポキシ樹脂組成物がスメクチック液晶構造を形成可能な温度の上限値（℃）であり、Ｂは前記エポキシ樹脂組成物がスメクチック液晶構造を形成可能な温度の下限値（℃）である。〕     A method for producing a cured epoxy resin, comprising a step of heat-treating the epoxy resin composition according to any one of claims 1 to 11, wherein the heat treatment is performed at a temperature X (° C) that satisfies the following formula.
    (B + 5 ℃) ≦ X ≦ (A-5 ℃)
    [Wherein, A is an upper limit value (° C.) at which the epoxy resin composition can form a smectic liquid crystal structure, and B is a lower limit value (° C.) at which the epoxy resin composition can form a smectic liquid crystal structure. ). ]
  16. 　前記エポキシ樹脂組成物がフィルムの状態で前記熱処理が行われる、請求項１５に記載のエポキシ樹脂硬化物の製造方法。 The method for producing a cured epoxy resin product according to claim 15, wherein the heat treatment is performed with the epoxy resin composition in a film state.
PCT/JP2018/005788 2018-02-19 2018-02-19 Epoxy resin composition, epoxy resin cured product, heat conductive film, and method for producing epoxy resin cured product WO2019159368A1 (en)

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JP2011074366A (en) * 2009-09-03 2011-04-14 Sumitomo Chemical Co Ltd Diepoxy compound, composition including the compound, cured product obtained by curing the composition
JP2014055251A (en) * 2012-09-13 2014-03-27 Mitsubishi Chemicals Corp Highly thermally conductive resin composition
WO2017175775A1 (en) * 2016-04-05 2017-10-12 日立化成株式会社 Resin composition, hydrogen gas barrier material, cured product, composite material, and structure
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