JP7740076B2 - Epoxy resin precursor composition, material for electronic components - Google Patents

Description

The present invention relates to an epoxy resin precursor composition that efficiently conducts heat generated inside electronic devices, and to a material for electronic components that uses the same.

In recent years, there has been a demand for packaging materials with high thermal conductivity to prevent the temperature of the internal semiconductors from becoming too high, such as in semiconductor elements used to control the power of hybrid and electric vehicles, and in CPUs for high-speed computers. In other words, the ability to efficiently dissipate heat generated by semiconductor chips to the outside has become important.

One way to solve this heat dissipation problem is to contact the heat-generating area with a highly thermally conductive material (hereinafter sometimes referred to as a heat dissipation component) to guide the heat to the outside and dissipate it. Examples of highly thermally conductive materials include inorganic materials such as metals and metal oxides. However, these inorganic materials have problems with processability and insulation, making them very difficult to use alone as fillers for semiconductor packages. For this reason, efforts are underway to develop heat dissipation components that combine these inorganic materials with resins to achieve high thermal conductivity.

Increasing the thermal conductivity of composite materials has generally been achieved by adding large amounts of inorganic fillers, such as metal fillers, to general-purpose resins such as polyethylene resin, polyamide resin, polystyrene resin, acrylic resin, and epoxy resin. However, the thermal conductivity of inorganic fillers is a substance-specific value with a set upper limit. Therefore, methods to increase the thermal conductivity of composite materials by improving the resin's thermal conductivity have been widely attempted. One known method for achieving this is to use liquid crystalline epoxy compounds and orient them (Non-Patent Document 1).

Non-Patent Document 1 discloses an epoxy resin with an internal structure that is vertically aligned between glass substrates. However, in this case, the orientation of the composition can be controlled by the glass substrates on both sides, making it relatively easy to achieve vertical alignment. However, for practical purposes, it is preferable to form the epoxy resin on a single-sided substrate.

Patent Document 1 also describes that a liquid crystalline composition can be vertically aligned on a single-sided glass substrate. However, it does not disclose information about compositions that can induce more vertical alignment, such as the film thickness at which the composition can be vertically aligned.

Japanese Patent Application Laid-Open No. 2022-8092

ACS Omega, 3, 3562 (2018).

The objective of the present invention is to provide an epoxy resin material with high thermal conductivity. It also aims to provide an epoxy resin precursor composition that provides the epoxy resin material.

The inventors discovered that a liquid crystal composition comprising a mixture of a liquid crystalline epoxy compound having a specific structure and a compound having a specific structure with a substituent that reacts with the epoxy compound, in a certain range, easily provides vertical alignment even on a single-sided substrate, and completed the present invention based on this finding.

The above liquid crystalline composition easily yields a cured product with a vertically aligned structure even in a relatively thick film, and has high thermal conductivity. Such materials can be suitably used as heat dissipation materials for power semiconductors, etc.

The following describes in detail an embodiment of the present invention. Note, however, that the present invention is not limited to the embodiment.

The present invention includes the following items:

[1] A composition comprising an epoxy compound and a curing agent,
The epoxy compound contains a compound represented by formula (1) in an amount of 50 mol % or more based on the total epoxy compounds,
The curing agent contains a compound having one aromatic ring and two or more epoxy-reactive substituents bonded to the aromatic ring in an amount of 50 mol % or more relative to the entire curing agent.
Epoxy resin precursor composition.


In formula (1), each R ^ep is independently a group having 2 to 12 carbon atoms and having an oxiranyl group; each X is independently a single bond, -CH ₂ CH ₂ -, -CH ₂ O-, -CH═CH-, -C≡C-, or -COO-; each Y is independently -CH ₂ - or -O-; each R ¹ is independently hydrogen, alkyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms, or R ^ep , where -CH ₂ - in at least one of these alkyl and alkoxy may be replaced with -CO-; and n is an integer of 0 to 2.

[2] The composition according to item [1], wherein in the compound represented by formula (1), at least one Y is —CH ₂ —.

[3] The composition described in item [1] or [2], wherein the compound has a structure having one aromatic ring and two or more epoxy-reactive substituents bonded to the aromatic ring, and the epoxy-reactive substituent is OH.

[4] The composition described in any one of items [1] to [3], wherein the aromatic ring in the compound has a structure having one aromatic ring and two or more epoxy-reactive substituents bonded to the aromatic ring, and the aromatic ring is benzene.

[5] The composition described in any one of items [1] to [4], containing a compound having a structure with one aromatic ring and two or more epoxy-reactive substituents bonded to the aromatic ring in an amount of 70 mol% or more relative to the total curing agent.

[6] The composition described in any one of items [1] to [5], further comprising a phenolic resin as a curing agent.

[7] The composition according to any one of items [1] to [6], wherein in the compound represented by formula (1), X is a single bond or -C≡C-.

[8] The composition described in any one of items [1] to [7], further comprising a curing accelerator.

[9] The composition described in item [8], further comprising a surfactant.

[10] The composition described in item [8] or [9], further comprising an inorganic filler.

[11] The composition described in item [10], wherein the inorganic filler is aluminum oxide, boron nitride, or aluminum nitride.

[12] A cured product obtained by curing the composition described in any one of items [1] to [11].

[13] A material for electronic components using the cured product described in item [12].

[Liquid Crystalline Epoxy Compounds]
The liquid crystalline epoxy compound preferably has a rod-shaped chemical structure, since this reduces crystallinity and makes it easier to form a paste. In such a rod-shaped liquid crystalline compound, the liquid crystal core preferably has 3 to 5 aromatic rings in order to expand the liquid crystal temperature range.

The core of the liquid crystal described above refers to a structure in which aromatic rings or alicyclic rings are linked by bonding groups with relatively defined conformations. Examples of such bonding groups include single bonds, ethylene, oxymethylene, double bonds, triple bonds, and ester bonds.

The rod-shaped liquid crystal compound has a structure in which aromatic rings or alicyclic rings are connected in a straight line as the liquid crystal core, with flexible substituents such as alkyls attached to both ends of the core. In this case, the straight line does not need to be strictly straight, and can be bent at an angle of up to about 45 degrees.

In such rod-shaped liquid crystal compounds, it is preferable that they do not contain esters in their molecular structure to prevent decomposition at temperatures above 200°C.

As the rod-shaped liquid crystal compound, it is more preferable to select a compound represented by formula (1) because it exhibits liquid crystallinity over a wide temperature range, is easy to manufacture, and has high heat resistance when cured.

In formula (1), each R ^ep is independently a group having 2 to 12 carbon atoms and having an oxiranyl group; each X is independently a single bond, -CH ₂ CH ₂ -, -CH ₂ O-, -CH═CH-, -C≡C-, or -COO-; each Y is independently -CH ₂ - or -O-; each R ¹ is independently hydrogen, alkyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms, or R ^ep , where -CH ₂ - in at least one of these alkyl and alkoxy may be replaced with -CO-; and n is an integer of 0 to 2.

In the compound of formula (1), each R ^ep is independently a group having an oxiranyl group and having 2 to 12 carbon atoms. In this case, there are no particular restrictions on the structure of R ^ep other than the oxiranyl group, but in order to impart high heat resistance to the cured product, it is preferably a group having an oxiranyl group having 2 to 10 carbon atoms, and particularly preferably a group having an oxiranyl group having 2 to 8 carbon atoms. Furthermore, -CH ₂ - in these groups having an oxiranyl group may be replaced with -O-.

In the compound of formula (1), the bonding groups X are each independently a single bond, -CH ₂ CH ₂ -, -CH ₂ O-, -CH═CH-, -C≡C-, or -COO-. In these bonding groups, the bonding direction is arbitrary. In this case, in order to improve the heat resistance of the cured product, it is preferable to select a single bond, -CH ₂ CH ₂ -, -CH ₂ O-, or -C≡C- as X, and in order to impart a wide liquid crystal temperature range to the compound, it is particularly preferable to select a single bond or -C≡C-. Furthermore, from the perspective of ease of synthesis, it is most preferable to select a single bond.

In the compound of formula (1), R ¹ is each independently hydrogen, alkyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms, or R ^ep . Furthermore, at least one —CH ₂ — in these alkyls and alkoxys may be replaced with —CO—. In this case, it is preferable to select alkyl or alkoxy as R ¹ , and it is particularly preferable to select alkyl, since this allows the liquid crystal temperature range of the compound to be expanded. Furthermore, when R ^ep and X are not the same group, it is also preferable to select hydrogen for the same reason. In order to expand the liquid crystal temperature range of the compound, it is most preferable to select methyl as R ^1. Furthermore, in order to improve the heat resistance of the cured product, it is preferable to select R ^ep as R ¹ .

In the compound of formula (1), when an organic group such as methyl is selected for R ¹ , it is preferably located adjacent to Y in order to improve the vertical alignment of the composition.

In the compound of formula (1), n is an integer from 0 to 2. In this case, n is preferably 1 or 2, as this allows the liquid crystal temperature range of the compound to be expanded.

Suitable examples of liquid crystalline epoxy compounds represented by formula (1) include compounds of formulas (1-1) to (1-31).

In formulas (1-1) to (1-31), R ^ep1 and R ^ep2 , other than oxiranyl, each independently represent a group having 2 to 11 carbon atoms and consisting of a carbon-carbon single bond and hydrogen bonded to carbon.

Of the compounds represented by formulas (1-1) to (1-31) above, in order to solve the problems of the present invention, it is preferable to select one of the compounds represented by formulas (1-6), (1-11) to (1-18), (1-22) to (1-23), and (1-30). These compounds have a wide liquid crystal temperature range, which is in a temperature range suitable for curing. Furthermore, in order to impart vertical alignment properties to the composition, it is most preferable to select formulas (1-6), (1-11), (1-13), and (1-30).

The composition of the present invention is characterized by containing the polymerizable compound used in the present invention, a curing agent, and a curing accelerator, which is added as needed. Such a composition of the present invention is likely to exhibit liquid crystallinity. Furthermore, by curing the composition while maintaining this state, the entanglement between the molecular skeletons in the cured product is alleviated. As a result, a material that efficiently conducts heat is obtained.

The composition of the present invention is characterized by containing a compound represented by formula (1) above. One or more compounds of formula (1) may be used. Furthermore, other known epoxy compounds can be used in combination, as long as they do not impair the liquid crystallinity of the composition. Liquid crystal epoxy compounds represented by formulas (o-1) to (o-6) are preferably used as such compounds.

Furthermore, as the other epoxy compounds, non-liquid crystal epoxy compounds represented by formulas (o-7) to (o-21) are also preferably used.

In formula (o-12), Z ¹⁰ represents a single bond, —CH ₂ —, —O—, —S—, —CH(CH ₃ )—, —C(CH ₃ ) ₂ —, —SO ₂ —, or —C(CF ₃ ) ₂ —.

In formula (o-13) and formula (o-14), Z ¹¹ represents —CH— or —CCH ₃ —.

As the other epoxy compounds, resins having structures represented by formulas (o-23) to (o-27) are also preferably used.

In formula (o-23), Z ¹² and Z ¹³ are independently a single bond, —CH ₂ —, —O—, —S—, —CH(CH ₃ ) —, —C(CH ₃ ) ₂ —, —SO ₂ —, or —C(CF ₃ ) ₂ —, and n21 is an integer of 1 or more and 5,000 or less.
In formula (o-24) and formula (o-25), n21 represents an integer of 1 or more and 5000 or less, n22 and n23 independently represent 0 or 1, and when n21 is 2 or more, it may be different for each repeat,
R ¹⁰ and R ¹¹ are independently 1,4-phenylene, 4,4′-biphenylene, or cyclopentadienylene;
In addition, hydrogen on the aromatic ring in these formulas (o-24) to (o-25) may be replaced with methyl.

In formula (o-26) and formula (o-27), Z ¹⁴ independently represents a single bond, —CH(CH ₃ )—, or —C(CH ₃ ) ₂ —, and n21 represents an integer of 1 or more and 5,000 or less.
In addition, hydrogen on the aromatic ring in formula (o-26) and formula (o-27) may be replaced by methyl.

The content of such known epoxy compounds relative to the compound of formula (1) can be determined from the perspective of ensuring that the composition or its cured product exhibits the desired properties and achieves the effects of the present invention. In other words, the compound of formula (1) is used in a proportion of 50 mol % or more, preferably 70 mol % or more, and more preferably 80 mol % or more, relative to the total epoxy compounds.

[Curing agent]
The curing agent that can be used in combination with the composition of the present invention must be one that does not inhibit the liquid crystallinity of the epoxy compound.

In order to improve the thermal conductivity in the thickness direction of a cured product made from the composition of the present invention, it is preferable that the liquid crystal phase exhibited by the composition is a smectic phase rather than a nematic phase. To achieve this, the curing agent must contain at least 50 mol%, preferably at least 70 mol%, and more preferably at least 80 mol%, of a compound having a structure containing one aromatic ring and two or more epoxy-reactive substituents bonded to the aromatic ring, relative to the total curing agent. Among the above compounds, it is preferable that the curing agent contain at least 50 mol% of a phenolic compound in which the epoxy-reactive substituent is OH, or a compound in which at least one of the OH groups in the phenolic compound is a short-chain ester.

In addition, all phenols other than the above compounds, or short-chain ester compounds in which at least one of the OH groups in the phenolic compound is a short-chain ester, can be used in combination with the above compounds.

The compound having one aromatic ring and two or more OH groups bonded to the aromatic ring is preferably a compound represented by formula (2), since it does not significantly impair the liquid crystal properties of the composition and is easily available.

In formula (2),
At least one hydrogen atom on the benzene ring may be replaced by alkyl having 1 to 3 carbon atoms, alkenyl having 2 to 3 carbon atoms, or alkoxy having 1 to 3 carbon atoms;
n21 is an integer of 2 or more and 4 or less.

The short-chain ester of a phenolic compound represented by the above formula (2) is a structure in which at least one of the OH groups in the phenolic compound becomes a short-chain ester, and the group represented by (3-E) below replaces the H of the OH.

In the formula, R ¹³ represents methyl, ethyl, propyl, butyl, pentyl, or hexyl, and propyl, butyl, pentyl, or hexyl may be branched. Among these R ¹³ , selecting methyl increases the crystallinity of the compound, which may impair the liquid crystallinity of the composition. In such cases, it is preferable to select (3-E) having a longer alkyl chain. On the other hand, in the case of a long alkyl chain, the heat resistance of the cured product may decrease. In such cases, it is preferable to select (3-E) having a shorter alkyl chain.

Other phenolic curing agents are preferably at least one phenolic compound represented by the following formulas (3-1) to (3-7) or its short-chain ester, as they do not significantly impair the liquid crystallinity of the composition and are readily available.

In formula (3-1),
Ring B is naphthalene, anthracene, fluorene, or 9,9-diphenylfluorene, and in these rings B, at least one hydrogen may be replaced by alkyl having 1 to 3 carbon atoms or alkoxy having 1 to 3 carbon atoms;
n31 is an integer of 2 or more and 4 or less.

In formula (3-2), n32 and n33 independently represent an integer of 1 to 3;
Z ³⁰ represents a single bond, alkylene having 1 to 10 carbon atoms, —CH(CH ₃ )—, —C(CH ₃ ) ₂ —, —C(CF ₃ ) ₂ —, —O—, —S—, or —SO ₂ —;
At least one hydrogen atom on the benzene ring may be replaced by alkyl having 1 to 3 carbon atoms or alkenyl having 2 to 3 carbon atoms;

In formula (3-3) and formula (3-4),
n34 is an integer of 1 or more and 5000 or less, n35 and n36 are independently 0 or 1, and when n34 is 2 or more, they may be different for each repeat;
R ¹⁰ and R ¹¹ are independently 1,4-phenylene, 4,4′-biphenylene, or cyclopentadienylene;
In formula (3-5),
n34 is an integer of 1 or greater and 5000 or less,
In formula (3-6),
Z ³¹ independently represents a single bond, —CH(CH ₃ )—, or —C(CH ₃ ) ₂ —; n34 represents an integer of 1 or more and 5,000 or less.
In formula (3-7),
n34 is an integer of 1 or more and 5000 or less, and R ¹² is hydrogen or methyl.
In addition, at least one hydrogen atom on the aromatic ring in these formulas (3-3) to (3-7) may be replaced with methyl.

The short-chain esters of phenolic compounds represented by the above formulas (3-1) to (3-7) are structures in which at least one of the OH groups in the phenolic compound becomes a short-chain ester, and the group represented by (3-E) below replaces the H of the OH.

In the formula, R ¹³ represents methyl, ethyl, propyl, butyl, pentyl, or hexyl, and propyl, butyl, pentyl, or hexyl may be branched. Among these R ¹³ , selecting methyl increases the crystallinity of the compound, which may impair the liquid crystallinity of the composition. In such cases, it is preferable to select (3-E) having a longer alkyl chain. On the other hand, in the case of a long alkyl chain, the heat resistance of the cured product may decrease. In such cases, it is preferable to select (3-E) having a shorter alkyl chain.

In addition to the known compounds such as phenols and carboxylic acid esters mentioned above, curing agents that can be used in the composition of the present invention include compounds such as amines, phenols, cyanate esters, carboxylic acids, carboxylic acid esters, acid anhydrides, and thiols.

The amine-based curing agent is preferably at least one compound represented by the following formula (4-1) or (4-2), since it does not significantly impair the liquid crystallinity of the composition and is easily available.
E-Z ²⁰ -(L-Z ²⁰ )n-E (4-1)
L ¹ -Z ²⁰ -E (4-2)
In the formulas (4-1) and (4-2),
Each L is independently a single bond, cyclohexylene, phenylene, or naphthalene, and at least one hydrogen atom in these rings may be replaced by alkyl having 1 to 10 carbon atoms;
L ¹ is hydrogen, cyclohexyl, phenyl, or naphthyl, and at least one hydrogen atom in these rings may be replaced by alkyl having 1 to 10 carbon atoms;
Z ²⁰ each independently represents a single bond, —O—, —NH—, —S—, —SO ₂ —, —CO ₂ —, or alkylene having 1 to 12 carbon atoms;
each E is independently amino, alkylamino having 1 to 10 carbon atoms, hydroxyl group, or carboxy, and at least one E is amino or alkylamino having 1 to 10 carbon atoms;
n is an integer from 0 to 7.

Examples of such compounds represented by formula (4-1) include aliphatic polyamines having 2 to 12 carbon atoms, such as ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, p-xylenediamine, and m-xylenediamine; p-phenylenediamine, N-methyl-p-phenylenediamine, N-ethyl-p-phenylenediamine, N-propyl-p-phenylenediamine, N-butyl-p-phenylenediamine, 2,5-diaminotoluene, m-phenylenediamine, N-methyl-m-phenylenediamine, N-ethyl-m-phenylenediamine, N-propyl-m-phenylenediamine, and N-butyl-m-phenylenediamine. aromatic polyvalent amines such as diaminodiamine, 2,4-diaminotoluene, 2,6-diaminotoluene, o-phenylenediamine, 1,5-diaminonaphthalene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 1,1-bis(4-aminophenyl)cyclohexane, 4,4'-diaminodiphenylsulfone, bis(4-aminophenyl)phenylmethane, m-tolidine, and o-tolidine; and alicyclic polyvalent amines such as 1,4-cyclohexyldiamine, 1,3-cyclohexyldiamine, 1,2-cyclohexyldiamine, and 1,3-bis(aminomethyl)cyclohexane.
Among these, p-phenylenediamine, N-methyl-p-phenylenediamine, N-ethyl-p-phenylenediamine, N-propyl-p-phenylenediamine, N-butyl-p-phenylenediamine, 2,5-diaminotoluene, m-phenylenediamine, N-methyl-m-phenylenediamine, N-ethyl-m-phenylenediamine, N-propyl-m-phenylenediamine, N-butyl-m-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenyl sulfone are particularly preferred because they have good compatibility when made into a composition and excellent storage stability.

Examples of compounds represented by formula (4-2) include aliphatic amines having 2 to 12 carbon atoms, such as n-propylamine, n-butylamine, n-pentylamine, n-hexylamine, n-octylamine, and n-dodecylamine; aromatic amines, such as aniline, o-toluidine, m-toluidine, p-toluidine, 2,3-dimethylaniline, 2,4-dimethylaniline, 2,6-dimethylaniline, 2,4,6-trimethylaniline, 2-ethylaniline, 1-naphthylamine, and 1-amino-2-methylnaphthalene; and alicyclic amines, such as cyclohexylamine and 2-methylcyclohexylamine. Among these, aniline, o-toluidine, m-toluidine, p-toluidine, 2,3-dimethylaniline, 2,4-dimethylaniline, 2,6-dimethylaniline, 2,4,6-trimethylaniline, and 2-ethylaniline are particularly suitable due to their good compatibility when made into a composition and excellent storage stability.

In the composition of the present invention, there are no particular restrictions on the ratio of epoxy compound to curing agent. In order to efficiently promote the reaction and improve heat resistance, it is preferable to use equivalent amounts of reactive groups in the epoxy compound and curing agent.

The above curing agents may be used alone or in combination with multiple types.

[Curing accelerator]
In the composition of the present invention, particularly when a phenolic curing agent is used, it is preferable to add a curing accelerator to the composition to efficiently promote the reaction and improve heat resistance. Examples of such curing accelerators include imidazole curing accelerators such as imidazole, 2-ethyl-4-methyl-1H-imidazole, 2-phenyl-4-methyl-1H-imidazole, 1,2-dimethylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, and 1-cyanoethyl-2-ethyl-4-methylimidazole; phosphorus curing accelerators such as triphenylphosphine; and amine curing accelerators such as 2,4,6-tris(dimethylaminomethyl)phenol, triethylenediamine, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, and 1,8-diazabicyclo[5.4.0]undec-7-ene. Among these curing accelerators, it is preferable to use imidazole-based curing accelerators because they have a curing temperature of 200° C. or less and have high curability.

The concentration of the curing accelerator in the composition of the present invention is preferably 0.1% by weight or more, and more preferably 0.5% by weight or more, based on the weight of the polymerizable compound used in the present invention, in order to efficiently promote the reaction and improve heat resistance. Furthermore, to avoid deterioration in reliability due to factors such as sublimation of the curing accelerator, the concentration is preferably 5% by weight or less, and more preferably 3% by weight or less, based on the weight of the polymerizable compound used in the present invention.

[Inorganic filler]
The composition of the present invention may contain an inorganic filler. Since the composition of the present invention can be suitably used for electronic components, the composition of the present invention used for electronic components may hereinafter be referred to as a composition for electronic components.
Examples of inorganic fillers contained in compositions for electronic components include nitrides such as aluminum nitride, boron nitride, and silicon nitride, which are highly thermally conductive fillers. Diamond, graphite, silicon carbide, silicon, beryllia, magnesium oxide, aluminum oxide, zinc oxide, silicon oxide, copper oxide, titanium oxide, cerium oxide, yttrium oxide, tin oxide, holminium oxide, bismuth oxide, cobalt oxide, calcium oxide, aluminum nitride, boron nitride, silicon nitride, magnesium hydroxide, aluminum hydroxide, gold, silver, copper, platinum, iron, tin, lead, nickel, aluminum, magnesium, tungsten, molybdenum, and stainless steel may also be used as inorganic fillers or metal fillers. Boron nitride, aluminum nitride, and aluminum oxide are preferred. Boron nitride and aluminum nitride are preferred because they have very high thermal conductivity in the planar direction, low dielectric constant, and high insulating properties. Hexagonal boron nitride (h-BN) and aluminum nitride are particularly preferred.

Inorganic fillers may be spherical, amorphous, fibrous, rod-like, cylindrical, plate-like, or tetrapod-like in shape. The type, shape, size, and amount of inorganic filler added can be selected appropriately depending on the purpose. For example, if a cured product formed from a composition for electronic components (hereinafter sometimes referred to as an electronic component material) requires insulation, the inorganic filler may be conductive as long as the desired insulation properties are maintained.

The average particle size of the inorganic filler is preferably, for example, 0.1 to 200 μm. It is more preferably 1 to 100 μm. A particle size of 0.1 μm or more provides good thermal conductivity, while a particle size of 200 μm or less allows for a higher filling rate. Note that the average particle size in this specification is based on particle size distribution measured using laser diffraction and scattering methods. In other words, using analysis based on the Fraunhofer diffraction theory and Mie scattering theory, when powder is divided into two particles at a certain particle size using a wet method, the median diameter is the diameter at which the larger and smaller particles are equal in volume (based on volume).

When used in a heat dissipation component, the amount of inorganic filler added is preferably 20 to 95% by weight. It is more preferably 50 to 95% by weight. Amounts of 20% by weight or more are preferred because they increase thermal conductivity. Amounts of 95% by weight or less are preferred because they do not make the heat dissipation component brittle.

Unmodified inorganic fillers may be used as is. Alternatively, fillers whose surfaces have been treated with a coupling agent may be used. For example, boron nitride (h-BN) may be treated with a silane coupling agent. Since boron nitride particles have no reactive groups on their surface, the silane coupling agent bonds only to their periphery. Boron nitride treated with a coupling agent can form bonds with polymerizable compounds in electronic component compositions, and these bonds are thought to contribute to thermal conductivity. Therefore, coupling agents that react with oxiranyl, oxetanyl, or groups possessed by curing agents are preferred. For example, amine-based agents or those containing oxiranyl or oxetanyl are preferred. Specific examples of such agents include Sila-Ace S310, Sila-Ace S320, Sila-Ace S330, Sila-Ace S360, Sila-Ace S510, and Sila-Ace S530, both of which are product names manufactured by JNC Corporation.

The inorganic filler may be treated with a coupling agent and then surface-modified with a compound having a polymerizable group (polymerizable compound) such as epoxy. For example, boron nitride (h-BN) treated with a silane coupling agent is surface-modified with a polymerizable compound. If boron nitride surface-modified with a polymerizable compound can form a bond with the polymerizable compound or curing agent in the composition for electronic components, this bond is thought to contribute to thermal conductivity. For example, the polymerizable compound may be the polymerizable compound used in the present invention represented by formula (1), or any other polymerizable compound.

[Other components]
Other components that can be contained in the composition of the present invention are not particularly limited, and examples thereof include a polymerizable compound having a polymerizable group other than epoxy, a non-polymerizable compound, a polymerization initiator, and a solvent.

The polymerizable compound having a polymerizable group other than epoxy is not particularly limited, and any known polymerizable compound can be used as long as it does not deteriorate the properties of the material for electronic components of the present invention. Among them, compounds that undergo radical polymerization, such as acrylic compounds and styrene-based compounds, are preferably used, and these compounds that have liquid crystallinity are more preferably used.
Examples of polymerization initiators include thermal polymerization initiators, photocationic polymerization initiators, and photoanionic polymerization initiators. Examples of thermal cationic polymerization initiators include sulfonium salts, boron trifluoride-amine complexes, dicyanazide, organic acid hydrazides, and toluenesulfonate esters. Known examples of photocationic polymerization initiators include sulfonium salts, iodonium salts, and nonionic initiators. Known examples of photoanionic polymerization initiators include oximes, carbamates, guanidinium carboxylates, and nifedipine.

When the composition of the present invention contains a compound that undergoes radical polymerization, such as an acrylic compound or a styrene-based compound, a radical polymerization initiator may be used.

The composition of the present invention may contain a solvent. Preferred solvents include, for example, 1,4-dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 3-methoxy-3-methyl-1-butanol, dipropylene glycol methyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, and diethylene glycol diethyl ether. Examples of suitable solvents include methyl ether, dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, methyl lactate, ethyl lactate, butyl lactate, 2-ethylhexanol, 1-propanol, isobutyl alcohol, n-butanol, 2-pentanone, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, diacetone alcohol, and ethylene glycol. These solvents may be used alone or in combination.

Because the composition of the present invention has high polymerizability, a stabilizer may be added to facilitate handling. Any known stabilizer can be used without restriction. Examples include hydroquinone, 4-ethoxyphenol, and 3,5-di-t-butyl-4-hydroxytoluene (BHT).

Additives (oxides, etc.) may also be added to adjust the viscosity and hue of the composition for electronic components. Examples include titanium oxide to produce a white color, carbon black to produce a black color, and silica fine powder to adjust viscosity. To further increase mechanical strength, inorganic fibers such as glass or carbon fiber, or their cloth, or synthetic fibers or supramolecules such as polyvinyl formal, polyvinyl butyral, polyester, polyamide, and polyimide may also be added.

It is known that the thermal conductivity of a material can be improved by controlling the alignment of the liquid crystal. For this purpose, it is preferable to add an alignment control agent, which controls the alignment of the liquid crystal, to the composition of the present invention. An example of a vertical alignment agent that aligns a liquid crystalline composition perpendicular to the substrate plane is a compound that has a hydrocarbon structure with 10 to 50 carbon atoms and has a hydroxyl group, amino, or carboxyl at one end of the structure.

[Electronic component materials]
The material for electronic components of the present invention is obtained by curing the composition for electronic components according to the preferred use of the composition of the present invention and molding the cured product according to the use. For example, the material for electronic components can be used as a heat dissipation member.

The material for electronic components is a polymer obtained by polymerizing (curing) the composition of the present invention. This polymer has high thermal conductivity and excellent chemical stability, heat resistance, hardness, and mechanical strength. The mechanical strength includes Young's modulus, tensile strength, tear strength, flexural strength, flexural modulus, and impact strength.

The composition of the present invention is a thermosetting resin. Thermosetting resins are cured by heating the raw material composition, which polymerizes the monomers contained in the composition and then three-dimensionally crosslinks the monomers. The heating temperature is preferably within a temperature range in which the composition of the present invention exhibits a liquid crystal phase. Furthermore, the liquid crystal temperature range of the composition of the present invention may increase as the curing proceeds to a certain extent. In such cases, the composition may be cured within the increased liquid crystal temperature range.

The curing temperature may be constant, or may be increased or decreased in stages. In the latter case, the initial curing temperature is preferably a temperature at which the composition or its cured product exhibits a liquid crystal phase, in order to improve the heat dissipation properties of the material. It is also preferable to heat the composition at a temperature higher than the initial curing temperature in order to improve heat resistance.

The thermosetting temperature for thermal polymerization is preferably in the range of 20°C to 350°C, more preferably 20°C to 250°C, and even more preferably 50°C to 200°C. The curing time is preferably in the range of 5 seconds to 10 hours, more preferably 1 minute to 8 hours, and even more preferably 5 minutes to 5 hours. After polymerization, it is preferable to slowly cool the product to suppress stress distortion. It is also possible to reheat the product to relieve distortion.

A crosslinking agent may be added to further crosslink the polymer. This results in a polymer (cured product) with excellent chemical and heat resistance. Any known crosslinking agent can be used without limitation, but examples include trimethylolpropane tris(3-mercaptopropionate).

The electronic component material of the present invention can be used in the form of a sheet, film, thin film, fiber, molded product, or the like. Films and thin films are preferred. Films and thin films can be obtained by polymerizing the electronic component composition in a state where it is applied to a substrate or sandwiched between substrates. Alternatively, the electronic component composition can be obtained by applying a solvent-containing electronic component composition to a substrate and then removing the solvent. Furthermore, films can also be obtained by press-molding the polymer. In this specification, the thickness of the sheet is preferably 1 mm or more, the thickness of the film is preferably 5 μm or more, more preferably 10 to 900 μm, and even more preferably 20 to 800 μm, and the thickness of the thin film is preferably less than 5 μm. The thickness can be adjusted appropriately depending on the application.

The electronic component material of the present invention not only has high thermal conductivity, but also excellent properties such as chemical stability, heat resistance, hardness, and mechanical strength. Therefore, it is useful for heat sinks, heat dissipation sheets, heat dissipation films, heat dissipation coatings, heat dissipation adhesives, and heat dissipation molded products.

The above description explains that the electronic component material formed from the polymerizable compound used in the present invention is used as a heat dissipation material, but the use of the electronic component material is not limited to heat dissipation materials. For example, it may also be used as a sealant or adhesive material.

[Method of manufacturing a composition for electronic components]
The composition for electronic components refers to a heat dissipation material, which is a preferred form of the composition of the present invention, and may contain an inorganic filler to enhance thermal conductivity, regardless of whether the inorganic filler is subjected to a coupling treatment. As an example of the production of a composition for electronic components, a production method in which the inorganic filler is subjected to a coupling treatment will be described below. Known methods can be used for the coupling treatment.

As an example, first add inorganic filler particles and a coupling agent to a solvent. Stir using a stirrer or similar device and then leave to stand. The solvent is allowed to air dry at room temperature, and then heat-treated under vacuum conditions using a vacuum dryer or similar device. The inorganic filler particles are then added to the solvent and pulverized using ultrasonic treatment. The solution is then separated and purified using a centrifuge. The supernatant is discarded, and the solvent is added, and the same process is repeated several times. The purified inorganic filler particles are then dried in an oven.

Next, the coupling-treated inorganic filler particles and polymerizable compound are mixed using an agate mortar or similar, and then kneaded using a two-axis roll or similar. The mixture is then separated and purified by ultrasonic treatment and centrifugation.

A phenolic curing agent is then added and mixed using an agate mortar or similar, and then kneaded using a two-screw roll or similar. This produces a solvent-free composition for electronic components.

[Method of manufacturing materials for electronic components]
As an example, a method for producing a film as a material for electronic components using a solvent-free composition for electronic components will be described below.

The solvent-free composition for electronic components is sandwiched between heating plates using a compression molding machine and molded by compression molding. The polymerizable compound polymerizes at a predetermined temperature and time to form a polymer. Post-curing may also be performed for an appropriate time and temperature. The pressure during compression molding is preferably 50 to 500 kgf/cm ² (4.90 to 49.0 MPa), more preferably 70 to 250 kgf/cm ² (6.86 to 24.5 MPa). Generally, higher pressures during curing are preferable. However, it is preferable to apply an appropriate pressure, adjusting it as needed depending on the fluidity of the mold and the desired physical properties (such as which direction of thermal conductivity is most important).

The composition for electronic components is easier to handle if it is partially cured (semi-cured). For example, the semi-cured composition can be formed into a sheet, cut into the desired shape, and then placed between suitable components and bonded together.

The following describes a method for producing a film as a material for electronic components using a solvent-containing composition for electronic components.

The composition for electronic components is applied to a substrate, and the solvent is then dried and removed to form a coating layer of uniform thickness. Coating methods include, for example, spin coating, roll coating, caten coating, flow coating, printing, microgravure coating, gravure coating, wire bar coating, dip coating, spray coating, and meniscus coating.

The solvent can be removed by drying, for example, air drying at room temperature, drying on a hot plate, drying in a drying oven, or by blowing warm or hot air. The conditions for solvent removal are not particularly limited; drying should be continued until the solvent is mostly removed and the coating layer loses its fluidity.

[Electronic Components]
An example of an electronic component is an electronic device having a heat-generating portion. When the material for electronic components of the present invention is used as a heat dissipation member, the heat dissipation member is placed on the electronic device so as to contact the heat-generating portion. The heat dissipation member may be in the form of a heat dissipation plate, a heat dissipation sheet, a heat dissipation film, a heat dissipation adhesive, a heat dissipation molded product, or the like. In this way, the heat dissipation member dissipates heat generated in the electronic device, preventing heat-related failures and thereby extending the life of electronic equipment incorporating the electronic device.

Examples of electronic devices include semiconductor elements. Heat dissipation materials have high thermal conductivity, high heat resistance, and high insulation. Therefore, they are particularly effective for insulated gate bipolar transistors (IGBTs), which require a more efficient heat dissipation mechanism due to their high power consumption. IGBTs are a type of semiconductor element, a bipolar transistor with a MOSFET incorporated into the gate, and are used for power control. Electronic devices equipped with IGBTs include the main conversion element of high-power inverters, uninterruptible power supplies, variable voltage and variable frequency control devices for AC motors, control devices for railway vehicles, electric transportation equipment such as hybrid cars and electric cars, and induction cookers.

[Method for synthesizing a compound represented by formula (1)]
The compound of formula (1) can be synthesized by combining known techniques in organic synthetic chemistry. Methods for introducing the desired polymerizable group and ring structure into starting materials are described in, for example, Houben-Weyl, Methods of Organic Chemistry, Georg Thieme Verlag, Stuttgart, Organic Syntheses, John Wiley & Sons, Inc., Organic Reactions, John Wiley & Sons, Inc., Comprehensive Organic Synthesis, Pergamon Press, and New Experimental Chemistry Lectures (Maruzen). Japanese Patent Application Laid-Open No. 2006-265527 may also be referenced.

The present invention will be explained in detail below using examples. However, the present invention is not limited to the contents described in the examples. Unless a temperature is specified, measurements were made at 23°C.

[NMR measurement]
NMR was measured using a VARIAN NMR SYSTEM manufactured by VARIAN. The magnetic field strength for ^1H NMR measurement was 500 MHz, the sample was dissolved in a deuterated solvent such as _CDCl3 , and the measurement was carried out at room temperature. The number of accumulations was 8. The internal standard was tetramethylsilane. In the NMR symbols, s means singlet, d means doublet, t means triplet, m means multiplet, and br means broad.

[Measuring the phase transition temperature of compounds and identifying liquid crystal phases]
Measurements were performed using a polarizing microscope and a differential scanning calorimeter. The polarizing microscope was a Nikon Corporation product, and a VHX5000 digital microscope (Keyence Corporation) equipped with a polarizing plate. A hot stage system HS1 (Mettler Toledo Co., Ltd.) was used to control the temperature. Polarizing microscope measurements were performed under crossed Nicols. The magnifications of the eyepiece and objective lens were 10x and 20x, respectively. A Perkin-Elmer Diamond DSC differential scanning calorimeter was used. The heating and cooling rates during measurements were both 3°C/min. In the examples, C indicates crystal, S indicates smectic phase, N indicates nematic phase, I indicates isotropic liquid, and () indicates monotropic liquid crystal phase.

[Verifying vertical alignment of the cured product]
Observation was performed using the polarizing microscope and on a backlight equipped with two polarizing plates. Both observations were performed under crossed Nicols conditions. If the composition is vertically aligned, the polarizing microscope observation results in a dark field. Also, when the sample is observed vertically on the backlight, no light is transmitted and the image appears black. On the other hand, when the sample is tilted away from the backlight, retardation occurs and light is transmitted. This is how vertical alignment was determined.

[Film thickness measurement]
The film thickness of the cured product was measured using a step gauge contact profiler P-17 (manufactured by KLA-TENCOR Corporation).

[Measurement of Thermal Conductivity 1] Measurement method for thin film samples consisting only of resin: The thermal diffusivity (α, m ² /s) of the sample was determined using a nanosecond thermoreflectance thin film thermal property measurement device manufactured by NETZSCH Co., Ltd. The measurement was performed using the backside heating/surface temperature measurement method. The thermal conductivity (κ, W/m·K) was calculated from the specific heat (c, J/(kg)) and density (ρ, g/m ³ ) of the sample according to the following formula:
κ = α × c × ρ
The specific heat was measured using a DSC-type high-sensitivity differential scanning calorimeter Thermo Plus EVO2 DSC-8231 manufactured by Rigaku Corp. The specific gravity was measured using a specific gravity balance type hydrometer DME-220 manufactured by Shinko Denshi Co., Ltd.

[Measurement of thermal conductivity 2]
Sample consisting of resin only: The thermal diffusivity (α, m ² /s) of the sample was determined using LFA467 HyperFlash manufactured by NETZSCH Co., Ltd. The thermal diffusivity was measured in both the in-plane direction and the thickness direction of the sample.
Filler-containing sample: The thermal diffusivity in the thickness direction of the sample was measured using an ai-Phase Mobile 1u thermal diffusivity measuring device manufactured by ai-Phase Corporation. The specific heat and density of the sample were also measured in the same manner as above. From these values, the thermal conductivity was calculated in the same manner as above.

[Epoxy compound]
As the polymerizable compound represented by formula (1), compounds represented by the following formulas (1-6-1), (1-10-1), and (1-11-1) to (1-11-3) were used in the examples. Formula (1-6-1) was synthesized as described in the synthesis example below. The other compounds were synthesized according to JP 2022-8092 A. As a comparative compound, a bisphenol F type epoxy compound with the trade name EPICLON EXA-830LVP (DIC Corporation) was used. This compound was purchased from DIC Corporation and used as is. The compound represented by the above formula (o-1) was also used. Compound (o-1) was synthesized according to Japanese Patent No. 5862479 A.

[Curing agent]
Methylhydroquinone (MeHQ) and 1,2,4-trihydroxybenzene (THB) were manufactured by Tokyo Chemical Industry Co., Ltd. and used as is without purification. The compound represented by formula (3-2-1) was synthesized according to JP 2022-8092 A. Vinylhydroquinone was synthesized according to J. Org. Chem., Vol. 63, 7298 (1998). Furthermore, bisphenol E, a comparative compound, was manufactured by Tokyo Chemical Industry Co., Ltd. and used as is without purification.

[Vertical alignment agent]
The compound represented by formula (p-1) was synthesized according to JP-A No. 2022-8092.

[Synthesis Example 1] Synthesis of compound represented by formula (1-6-1)

A mixture of 50.0 g (233 mmol) of commercially available 4-bromo-2-methylbenzoic acid, 42 ml (581 mmol) of thionyl chloride, and 2 drops of dimethylformamide was refluxed in toluene (230 ml) for 3.5 hours. The thionyl chloride and solvent were removed by distillation under reduced pressure, and the residue was dried in vacuo to obtain 4-bromo-2-methylbenzoyl chloride. Yield: 54.0 g (99%).

37.5 g (277 mmol) of 4-bromo-1-butene was dissolved in 500 ml of tetrahydrofuran and added to a flask containing 7.30 g (300 mmol) of magnesium over 1 hour. The mixture was stirred at room temperature for 4 hours. A mixture of 54.0 g (231 mmol) of 4-bromo-2-methylbenzoyl chloride, 6.80 g (35.7 mmol) of copper(I) iodide, and 400 ml of tetrahydrofuran was cooled to -40°C, and the prepared Grignard reagent was added over 1 hour. The mixture was then returned to room temperature and stirred overnight. The reaction mixture was added to 1 L of saturated aqueous ammonium chloride solution, filtered through Celite, and the filtrate was extracted with 1 L of toluene. The organic layer was washed with 1 _L of purified water, dried over anhydrous MgSO4, filtered, and the solvent was removed under reduced pressure. The resulting brown oil was purified by column chromatography (silica gel, toluene/heptane = 4/1 → 2/1, volume ratio) to obtain 49.7 g (85% yield) of 1-(4-bromo-2-methylphenyl)-4-penten-2-one.

To a mixture of 10.0 g (39.5 mmol) of 1-(4-bromo-2-methylphenyl)-pent-4-en-2-one and 20 ml (265 mmol) of trifluoroacetic acid, 14 ml (86.9 mmol) of triethylsilane was added at 0°C. The reaction mixture was returned to room temperature and stirred for 4 hours. Heptane (100 ml) and purified water (80 ml) were then added, and the mixture was separated. The organic layer was washed with saturated aqueous sodium bicarbonate solution (80 ml) and saturated brine (80 ml), dried over anhydrous _MgSO4 , filtered, and the solvent was evaporated under reduced pressure. The resulting brown oil was purified by column chromatography (silica gel, heptane) to obtain 4-bromo-1-(4-butenyl)-2-methylbenzene. Yield: 6.32 g (67%).

7.11 g (29.7 mmol) of 4-bromo-1-(4-butenyl)-2-methylbenzene was dissolved in 30 ml of tetrahydrofuran and cooled to -50°C. 19 ml of a 1.56 M nBuLi-n-hexane solution was added and stirred for 1 hour. 7.6 ml (32.7 mmol) of triisopropyl borate was added, and the mixture was returned to room temperature and stirred for 2 hours. The reaction mixture was cooled to 0°C, 30 ml of 2 M hydrochloric acid was added, and the mixture was stirred for 30 minutes. The reaction mixture was extracted with ethyl acetate (100 ml). The organic layer was washed with purified water (80 ml) and saturated brine (80 ml), dried over anhydrous MgSO ₄ , filtered, and the solvent was distilled off under reduced pressure. The residue was purified by column chromatography (silica gel, toluene/ethyl acetate = 4/1, volume ratio) to obtain 4-(4-butenyl)-3-methylphenylboronic acid. Yield: 4.10 g (67%).

Compound (1-6-1-b) was synthesized using 4-(4-butenyl)-3-methylphenylboronic acid and compound (1-6-1-a) in a manner similar to Example 4 described in JP-A 2022-8092. The product was purified by column chromatography (silica gel, heptane/toluene = 1/1, volume ratio) and recrystallization (toluene/ethanol). Yield: 0.98 g (39%).

The compound represented by formula (1-6-1-b) was oxidized using mCPBA (metachloroperbenzoic acid) using a method similar to that described in JP 2022-8092 A. The resulting product was purified by column chromatography (silica gel, toluene/ethyl acetate = 20/1, volume ratio) and recrystallization (ethanol) to obtain compound (1-6-1). Yield: 0.67 g (64%).

Phase transition point (℃); C・78.9・Sm・108.3N・125.7・I
¹ H-NMR (ppm, CDCl ₃ ); 7.61, 7.58, 7.37, 7.30 (AA'BB', 8H), 7.20 (d, 1H, J = 8.50Hz), 6.85 (d, 1H, J = 3.00Hz), 6.81 (dd, 1H, J = 8.00, 2.50Hz), 4. 20-4.13, 3.20-3.16, 3.01-3.00, 2.86-2.77, 2.62-2.60, 2.53-2.50 (m, 10H), 2.31 (s, 3H), 2.14-2.10, 2.00-1.88 (m, 4H).

Example 1 Preparation of Composition and Confirmation of Solubility 0.5000 g (1.300 mmol) of the compound represented by formula (1-6-1) synthesized in Synthesis Example 1 and 0.1614 g (1.300 mmol) of MeHQ were placed in a sample bottle, and cyclopentanone (2.78 ml) was added to dissolve the solid content, yielding a composition (Composition 1) with a solid content concentration of approximately 20 wt %. When Composition 1 was left to stand overnight in a refrigerator set to 0°C, no precipitation occurred and the composition remained in its original state.

[Example 2] to [Example 16]
The following composition solutions (Compositions 2 to 16) with solid content concentrations of approximately 20% by weight were prepared in the same manner as in Example 1, except that the epoxy compound and curing agent were changed as shown in Table 1 below, and their solubility was confirmed. In Table 1, columns listing two types of epoxy compounds or curing agents indicate that these were mixed, and the proportions thereof are shown afterward as the molar ratio of each compound. The molar ratio of epoxy compound to curing agent in each composition was 1/1. The results are shown in Table 1 together with the results of Example 1.

Table 1. Compositions and their solubilities (solvent: cyclopentanone)

[Comparative Example 1] to [Comparative Example 5]
The following composition solutions (compositions r1 to r5) with a solids concentration of approximately 20% by weight were prepared and their solubility was confirmed in the same manner as in Example 1, except that the epoxy compound and curing agent were changed as shown in Table 2 below. In Table 2, columns listing two types of curing agents indicate that these were mixed, and the proportions are shown afterwards as the molar ratio of each compound. The molar ratio of epoxy compound to curing agent in each composition was 1/1. The results are shown in Table 2.

Table 2. Compositions and their solubilities (solvent: cyclopentanone)

[Example 17] Confirmation of vertical alignment on a single-sided glass substrate Imidazole was added as a curing accelerator to composition 1 prepared in Example 1 above. The imidazole was added in an amount of 1 wt % based on the solids weight to obtain a curable composition (curable composition 17). A few drops of this curable composition 17 were placed on a glass slide and baked for 1 hour on a hot plate set at 115°C to obtain a cured product (cured product 1). This cured product 1 was confirmed to be vertically aligned. Furthermore, observation under a polarizing microscope confirmed that there were no alignment defects in the observed region. Furthermore, the film thickness of this cured product 1 was measured and found to be 23 μm at its thickest region.

[Example 18] to [Example 32]
Curing compositions 18 to 32 were prepared using compositions 2 to 16 in the same manner as in Example 17. Using these curing compositions 18 to 32, vertical alignment on a single-sided glass substrate was confirmed in the same manner as in Example 17 (cured products 2 to 16). The results are shown in Table 3 together with the results of Example 17.

Table 3 Confirmation of vertical alignment on a single-sided glass substrate

[Comparative Example 6] to [Comparative Example 10]
Curing compositions r6 to r10 were prepared using compositions r1 to r5 in the same manner as in Example 17. Vertical alignment of these curing compositions r6 to r10 on a single-sided glass substrate was confirmed in the same manner as in Example 17 (cured products r1 to r5). The results are shown in Table 4.

Table 4 Confirmation of vertical alignment on a single-sided glass substrate

The results of Examples 17 to 32 and Comparative Examples 6 to 10 above demonstrate that the composition of the present application has extremely high vertical alignment properties even in relatively thick films of approximately 20 μm.

Example 33: Confirmation of vertical alignment on a single-sided glass substrate and measurement of thermal conductivity of a cured product prepared from composition 12. 2-Methylimidazole as a curing accelerator and TegoFlow 370 as a leveling agent were added to composition 12 prepared in Example 12 above. The 2-methylimidazole and TegoFlow 370 were added in amounts of 1 wt % and 0.3 wt %, respectively, based on the solid content weight, to obtain a curable composition (curable composition 33). A few drops of this curable composition 33 were applied to the deposition side of a 33 x 27 x 0.5 mm glass substrate on which 106 nm of aluminum had been deposited, and the resulting film was applied using a spin coater. Spin coating was performed at 600 rpm for 10 seconds. The spin-coated glass substrate was baked for 120 minutes on a hot plate heated to 115°C, obtaining a cured product (cured product 17) coated over the entire deposition side of the glass substrate. When light was reflected off an aluminum surface, no cloudiness was observed in this cured product 17. Furthermore, when a quarter-wave plate was placed above the sample and the sample was observed in the same manner, no light was transmitted when observed vertically, but some light was transmitted when observed from an oblique angle. From these findings, it is believed that the molecular structure of cured product 17 is vertically oriented.

The substrate with this cured film (cured product 17) was cooled to room temperature, and then aluminum was vapor-deposited to a thickness of 106 nm on the coated surface of cured product 17.

[Comparative Example 11]
A curable composition (curable composition r11) was obtained by adding 2-methylimidazole and TegoFlow 370 to the composition r4 prepared in Comparative Example 4 in the same manner as in Example 33. A cured product sample (cured product r6) was prepared using this curable composition r11 in the same manner as in Example 33.

When observing a sample with no aluminum vapor deposition on top, no cloudiness was observed when light was reflected off the aluminum surface. Furthermore, when a quarter-wave plate was placed on top of the sample and observed in the same way, no light was transmitted when observed vertically or at an angle. From these findings, it is believed that the molecular structure of cured product r6 is unoriented (isotropic).

The thermal conductivity in the thickness direction of cured product 17 and cured product r6 produced in Example 33 and Comparative Example 11 was measured using the method described in Thermal Conductivity Measurement 1, and the results are shown in Table 5.

Table 5. Measurement results of thermal conductivity of thin films

As shown in Table 5, cured material 17, which has a vertically aligned structure inside and is prepared from the composition of the present invention, has a thermal conductivity 1.7 times higher than cured material r6, which uses a general epoxy resin.

Example 34 Measurement of thermal conductivity of cured product prepared from curing composition 17 The above curing composition 17 was placed in an aluminum container with a diameter of 2.4 cm and held on a hot plate heated to 115°C for 120 minutes. A circular piece with a thickness of 1.0 mm was removed to obtain a cured product (cured product 18). This was measured using the thermal conductivity measurement method 2. The thermal conductivity of this cured product 18 was 0.44 W/m K and 0.80 W/m K in the in-plane direction and thickness direction of the sample, respectively.

[Example 35] to [Example 49]
Cured products (cured products 19 to 33) were obtained using curing compositions 18 to 32 in the same manner as in Example 34. The thermal conductivity of these cured products 19 to 33 was measured, and the results are shown in Table 6 together with the results of Example 34.

Table 6. Thermal conductivity of the composition

[Comparative Example 12] to [Comparative Example 15]
Cured products (cured products r7 to r10) were obtained using curing compositions r6 to r9 in the same manner as in Example 34. The thermal conductivity of these cured products r7 to r10 was measured, and the results are shown in Table 7.

Table 7. Thermal conductivity of the composition

Comparison with Examples 34 to 49 and Comparative Examples 12 to 15 reveals that cured products 18 to 33 prepared from the compositions of the present invention have particularly high thermal conductivity in the thickness direction of the samples.

Example 50 Preparation of Filler-Containing Sample 0.4 g of curing composition 17 and 0.92 g of boron nitride particles (manufactured by Momentive Performance Materials Japan Co., Ltd., trade name: PolarTherm, grade name: PTX-25) were weighed out and mixed well, and then left to stand on a hot plate heated to 80 ° C for 5 minutes. After that, the sample was sandwiched between stainless steel plates and held for 45 minutes under a pressure of 20 MPa in a compression molding machine (IMC-19EC manufactured by Imoto Machinery Co., Ltd.) heated to 150 ° C. A square piece having a thickness of 523 μm was taken out as a heat dissipation member to obtain filler-containing sample 17. The thermal conductivity of this sample (filler-containing sample 17) was 20.4 W / m K.

[Example 51] and [Example 52]
Filler-containing sample 22 and filler-containing sample 26 were prepared and their thermal conductivities were measured in the same manner as in Example 50, except that curing compositions 22 and 26 were used instead of curing composition 17. The results are shown in Table 8, along with the results of Example 50.

Table 8 Thermal conductivity of samples containing boron nitride

[Example 53] to [Example 55]
0.92 g of aluminum oxide particles (manufactured by Denka Co., Ltd., product name: Denka spherical alumina, grade name: DAW-10) was weighed out and mixed thoroughly with 0.4 g of each of curing compositions 17, 22, and 26, and filler-containing sample 17 _AO , filler-containing sample 22 _AO , and filler-containing sample 26 _AO were prepared in the same manner as in Example 50, and their thermal conductivities were measured. The results are shown in Table 9.

Table 9 Thermal conductivity of samples containing aluminum oxide particles

[Example 56] to [Example 58]
0.92 g of aluminum nitride particles (manufactured by Thrutek Corporation; trade name: aluminum nitride (ALN) powder, part number: AlN300RW; and manufactured by Tokuyama Corporation; trade name: high-purity aluminum nitride (AlN) powder, grade name: H grade 68 wt % to 32 wt % mixture) were weighed out and mixed thoroughly with 0.4 g of curing composition 17, curing composition 22, and curing composition 26, and the filler-containing sample 17 _ALN , filler-containing sample 22 _ALN , and filler-containing sample 26 _ALN were prepared in the same manner as in Example 50, and their thermal conductivity was measured. The results are shown in Table 10.

Table 10 Thermal conductivity of samples containing aluminum nitride particles

As described above, it can be seen that the technology disclosed in this invention provides high thermal conductivity.

The technology of the present invention can be suitably used as a packaging material for semiconductor devices. It can also be used as an alternative to other epoxy resins, such as adhesives.

Claims (12)

A composition comprising an epoxy compound and a curing agent,
The epoxy compound contains a compound represented by formula (1) in an amount of 50 mol % or more based on the total epoxy compounds,
the curing agent contains a compound having one aromatic ring and two or more epoxy-reactive substituents bonded to the aromatic ring, the epoxy-reactive substituents being OH , in an amount of 50 mol % or more relative to the entire curing agent;
Epoxy resin precursor composition.

In formula (1), each R ^ep is independently a group having an oxiranyl group having 2 to 12 carbon atoms ; each X is independently a single bond, -CH ₂ CH ₂ -, -CH ₂ O-, -CH═CH-, -C≡C-, or -COO-; each Y is independently -CH ₂ - or -O-; each R ¹ is independently hydrogen, alkyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms, or R ^ep , where at least one -CH ₂ - in these alkyl and alkoxy may be replaced with -CO-; and n is 1 or 2. 2. The composition according to claim 1, wherein in the compound represented by formula (1), at least one Y is —CH ₂ —. 3. The composition according to claim 1, wherein the aromatic ring in the compound has a structure having one aromatic ring and two or more substituents bonded to the aromatic ring that react with epoxy, and the aromatic ring is benzene. The composition according to any one of claims 1 to 3 , comprising a compound having a structure having one aromatic ring and two or more epoxy-reactive substituents bonded to the aromatic ring in an amount of 70 mol% or more relative to the entire curing agent. The composition according to any one of claims 1 to 4 , further comprising a phenolic resin as a curing agent. The composition according to any one of claims 1 to 5 , wherein in the compound represented by formula (1), X is a single bond or -C≡C-. The composition according to any one of claims 1 to 6 , further comprising a cure accelerator. The composition of claim 7 further comprising a surfactant. The composition of claim 7 or 8 , further comprising an inorganic filler. The composition of claim 9 , wherein the inorganic filler is aluminum oxide, boron nitride, or aluminum nitride. A cured product obtained by curing the composition according to any one of claims 1 to 10 . A material for electronic parts using the cured product according to claim 1 .