JP2015067830A - Epoxy resin, epoxy resin composition, prepreg and cured product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high purity epoxy resin containing a mesogenic group, which can make an uniformly cured product and has high thermal conductance.SOLUTION: An epoxy resin mixture contains an epoxy resin obtained through the steps (A) to (B), where the total area ratio of a specific epoxy compound in GPC is in a specific range and 3.1 to 20 area% of the resin represented by the formula (3) is contained. Step (A): a specific hydroxyacetophenone-based compound and a specific hydroxybenzaldehyde compound are reacted to obtain a phenolic compound (a). Step (B): the phenolic compound (a) obtained in the step (A) is reacted with epihalohydrin by a known technique to obtain an epoxy resin.

Description

  The present invention relates to a novel epoxy resin and epoxy resin composition. Moreover, it is related with hardened | cured materials, such as a prepreg formed with this epoxy resin composition.

  Epoxy resin compositions are generally cured products with excellent mechanical properties, water resistance, chemical resistance, heat resistance, electrical properties, etc., such as adhesives, paints, laminates, molding materials, casting materials, etc. It is used in a wide range of fields. In recent years, cured products of epoxy resins used in these fields have begun to be highly purified and have various properties such as flame retardancy, heat resistance, moisture resistance, toughness, low linear expansion coefficient, and low dielectric constant characteristics. There is a need for improvement.

  In particular, in the electrical and electronic industry, which is a typical application of epoxy resin compositions, high-density mounting of semiconductors and high-density wiring of printed wiring boards have been promoted for the purpose of multi-function, high performance, and compactness. Although progress is being made, the heat generated from the inside of a semiconductor element or a printed wiring board increases with high-density mounting or high-density wiring, which may cause malfunction. Therefore, how to efficiently release generated heat to the outside is an important issue from the standpoint of energy efficiency and device design. These heat countermeasures include various measures such as using a metal core substrate, constructing a structure that easily dissipates heat at the design stage, and densely filling high thermal conductive filler in the polymer material (epoxy resin) to be used. Has been made. However, since the thermal conductivity of the polymer material acting as a binder that connects the high thermal conductivity sites is low, the thermal conduction speed of the polymer material becomes the rate-determining, and efficient heat dissipation is not possible at present.

  As a means for realizing high thermal conductivity of an epoxy resin, it is reported in Patent Document 1 that a mesogenic group is introduced into the structure. In the same document, as an epoxy resin having a mesogenic group, an epoxy resin having a biphenyl skeleton, etc. Is described. In addition, as an epoxy resin other than the biphenyl skeleton, a phenyl benzoate type epoxy resin is described. However, since the epoxy resin needs to be produced by an epoxidation reaction by oxidation, there are difficulties in safety and cost, and it is practical. It can not be said. Examples of using an epoxy resin having a biphenyl skeleton include Patent Documents 2 to 4, and among them, Patent Document 3 describes a technique in which an inorganic filler having high thermal conductivity is used in combination. However, the thermal conductivity of the cured product obtained by the methods described in these documents is not at a level that satisfies the market demand, and a cured product having higher thermal conductivity using an epoxy resin that is available at a relatively low cost. There is a need for an epoxy resin composition that provides.

  In addition, high heat conductive epoxy resins having a mesogenic group that have been reported so far have a very high melting point, making it difficult to take out the resinous form, and many of them have poor solvent solubility. Since such an epoxy resin begins to cure before being completely melted during curing, it is difficult to produce a uniform cured product, which is not preferable.

  In view of such a current situation, Patent Document 5 has developed a high thermal conductive resin having a mesogenic group and a low melting point. However, since the epoxy resin described in this document has a high reactivity at the α, β-unsaturated carbonyl moiety, it tends to be easily decomposed during production, and the thermal conductivity tends to be impaired.

JP-A-11-323162 Japanese Patent Laid-Open No. 2004-2573 JP 2006-63315 A JP 2003-137971 A International Publication No. 2011/093474

  The present invention has been made as a result of studies to solve such problems, and since the mesogenic group-containing epoxy resin has a high purity, the cured product of the epoxy resin having high thermal conductivity, An epoxy resin composition containing an epoxy resin, a prepreg, and a cured product thereof are provided.

（式（３）中、Ｒ_１、Ｒ_２、ｋ、ｌは下記と同じ意味を表し、Ｙはオキシグリシジル基又は下記式（４）

（式（４）中、Ｒ_３は水素原子、炭素数１〜６のアルキル基を表す。）
を表し、Ｙのうち少なくとも一つは上記式（４）である。）
で表される樹脂を高速液体クロマトグラフィーでの測定において３．１〜２０面積％含有するエポキシ樹脂混合物、
工程（イ）：下記式（１） As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.
That is, the present invention
(1) The total area ratio of the epoxidized products of the following formulas (1) and (2) in GPC among the epoxy resins obtained through the following steps (a) to (b) (hereinafter referred to as low molecular weight area) Ratio) is 0.5 to 5 area% in the measurement by high performance liquid chromatography, and the following formula (3)

(In the formula (3), R ₁ , R ₂ , k, and l have the same meaning as described below, and Y represents an oxyglycidyl group or the following formula (4).

(In formula (4), R ₃ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
And at least one of Y is represented by the above formula (4). )
An epoxy resin mixture containing 3.1 to 20 area% of the resin represented by
Process (I): following formula (1)

(In Formula (1), each R ₁ is independently present and is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a hydroxyl group, Represents either a nitro group or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, l represents the number of R ₁ , and is an integer of 0 to 4);
Following formula (2)

(In Formula (2), each R ₂ is independently present, a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a hydroxyl group, It represents any of a nitro group, a formyl group, an allyl group, or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, where k represents the number of R ₂ and is an integer of 0 to 4. Obtaining a phenol compound (a) by reaction with a compound;
Step (b): A step of obtaining the epoxy resin of the present invention by reacting the phenol compound (a) obtained by the step (i) with epihalohydrin by a known method,

(2) An epoxy resin composition comprising the epoxy resin according to the preceding item (1) and a curing agent and / or a curing accelerator,
(3) The epoxy resin composition according to item (2), which contains an inorganic filler having a thermal conductivity of 20 W / m · K or more,
(4) The epoxy resin composition according to (2) or (3), which is used for semiconductor sealing applications,
(5) A prepreg comprising the epoxy resin composition according to the preceding item (2) or (3) and a sheet-like fiber base material,
(6) A cured product obtained by curing the epoxy resin composition according to any one of (2) to (4), or the prepreg according to (5),
About.

  Since the epoxy resin mixture of the present invention contains a mesogen group-containing epoxy resin with high purity, the cured product exhibits excellent thermal conductivity, various composite materials including a semiconductor sealing material, a prepreg, an adhesive, This is useful when used in paints. In addition, the epoxy resin of the present invention has a low softening point, so it is easy to produce a uniform cured product, and since it contains a resin represented by the following formula (3) that has been ring-opened at a certain ratio, it is solvent-soluble. And is also useful as a prepreg.

  First, the phenol compound (a) will be described. The phenol compound (a) is obtained by a reaction between a compound represented by the following formula (1) and a compound represented by the following formula (2).

(In Formula (1), each R ₁ is independently present and is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a hydroxyl group, It represents either a nitro group or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, where l represents the number of R ₁ and is an integer of 0 to 4.

In Formula (1), each R ₁ is independently present and is a hydrogen atom, an unsubstituted alkyl group having 1 to 10 carbon atoms, an unsubstituted aryl group having 6 to 10 carbon atoms, a hydroxyl group, a nitro group, or a carbon number. It is preferable that it is a 1-10 unsubstituted alkoxy group.

  Specific examples of the compound represented by the formula (1) used for the reaction with the compound represented by the formula (2) in order to obtain the phenol compound (a) include 2-hydroxyacetophenone, 3-hydroxyacetophenone, 4-hydroxyacetophenone, 2 ′, 4′-dihydroxyacetophenone, 2 ′, 5′-dihydroxyacetophenone, 3 ′, 4′-dihydroxyacetophenone, 3 ′, 5′-dihydroxyacetophenone, 2 ′, 3 ′, 4′- Trihydroxyacetophenone, 2 ′, 4 ′, 6′-trihydroxyacetophenone monohydrate, 4′-hydroxy-3′-methylacetophenone, 4′-hydroxy-2′-methylacetophenone, 2′-hydroxy-5 ′ -Methylacetophenone, 4'-hydroxy-3'-methoxyacetophenone, 2 ' Hydroxy-4'-methoxyacetophenone, 4'-hydroxy-3'-nitroacetophenone, 4'-hydroxy-3 ', 5'-dimethoxyacetophenone, 4', 6'-dimethoxy-2'-hydroxyacetophenone, 2'- Hydroxy-3 ′, 4′-dimethoxyacetophenone, 2′-hydroxy-4 ′, 5′-dimethoxyacetophenone, methyl 5-acetylsalicylate, 2 ′, 3′-dihydroxy-4′-methoxyacetophenone hydrate, and the like. It is done. Among these, 4′-hydroxy-3′-methoxy has high solvent solubility when the obtained phenol compound (a) is epoxidized and the cured product of the epoxy resin composition exhibits high thermal conductivity. Acetophenone, 4′-hydroxyacetophenone is preferred.

(In Formula (2), each R ₂ is independently present, a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a hydroxyl group, Any one of a nitro group, a formyl group, an allyl group, or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, k represents the number of R ₄ , and is an integer of 0 to 4)

  Specific examples of the compound represented by the formula (2) used for the reaction with the compound represented by the formula (1) in order to obtain the phenol compound (a) include, for example, 2-hydroxybenzaldehyde, 3-hydroxy Benzaldehyde, 4-hydroxybenzaldehyde, 2,3-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 2,5-dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, syringaldehyde, 3,5-di-tert-butyl-4 -Hydroxybenzaldehyde, isovanillin, 4-hydroxy-3-nitrobenzaldehyde, 5-hydroxy-2-nitrobenzaldehyde, 3,4-dihydroxy-5-nitrobenzaldehyde, vanillin, o-vanillin, 2-hydroxy-1-naphthaldehyde 2-hydroxy-5-nitro-m-anisaldehyde, 2-hydroxy-5-methylisophthalaldehyde, 2-hydroxy-4-methoxybenzaldehyde, 1-hydroxy-2-naphthaldehyde, 2-hydroxy-5-methoxybenzaldehyde 5-nitrovanillin, 5-allyl-3-methoxysalicylaldehyde, 3,5-di-tert-butylsalicylaldehyde, 3-ethoxysalicylaldehyde, 4-hydroxyisophthalaldehyde, 4-hydroxy-3,5-dimethylbenzaldehyde 2,4,6-trihydroxybenzaldehyde, 2,4,5-trihydroxybenzaldehyde, 2,3,4-trihydroxybenzaldehyde, 3,4,5-trihydroxybenzaldehyde, 3-ethoxy-4-hydroxybenzaldehyde 'S aldehyde, and the like. These may use only 1 type or may use 2 or more types together. Among these, it is preferable to use vanillin alone because it has high solvent solubility when the resulting phenol compound (a) is epoxidized, and the cured product of the epoxy resin composition exhibits particularly high thermal conductivity. .

The phenol compound (a) is obtained by an aldol condensation reaction between one or more compounds represented by the formula (1) and a compound represented by the formula (2) under acidic conditions or basic conditions.
The compound represented by the formula (2) is used in an amount of 1.0 to 1.05 mol with respect to 1 mol of the compound represented by the formula (1).

  When the aldol condensation reaction is performed under acidic conditions, examples of the acidic catalyst that can be used include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid, and organic acids such as toluenesulfonic acid, xylenesulfonic acid, and oxalic acid. These may be used alone or in combination of a plurality of types. The usage-amount of an acidic catalyst is 0.01-1.0 mol with respect to 1 mol of compounds represented by Formula (2), Preferably it is 0.2-0.5 mol.

  On the other hand, when the aldol condensation reaction is performed under basic conditions, usable basic catalysts include metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as potassium carbonate and sodium carbonate, diethylamine, Examples include amine derivatives such as triethylamine, tributylamine, diisobutylamine, pyridine and piperidine, and amino alcohol derivatives such as dimethylaminoethyl alcohol and diethylaminoethyl alcohol. Also in the case of basic conditions, the basic catalysts listed above may be used alone, or a plurality of types may be used in combination. The usage-amount of a basic catalyst is 0.1-2.5 mol with respect to 1 mol of compounds represented by Formula (2), Preferably it is 0.2-2.0 mol.

  In the reaction for obtaining the phenol compound (a), a solvent may be used as necessary. The solvent that can be used is not particularly limited as long as it is not reactive with the compound represented by the formula (2) such as ketones, but the compound represented by the formula (2) as a raw material can be easily used. It is preferable to use alcohols as the solvent in terms of dissolution in the solvent.

  The reaction temperature is usually 10 to 90 ° C, preferably 35 to 70 ° C. Although reaction time is 0.5 to 10 hours normally, since there is a difference in reactivity with the kind of raw material compound, it is not this limitation. When taking out as a resin after completion | finish of reaction, an unreacted substance, a solvent, etc. are removed from a reaction liquid under heating and pressure reduction, after washing | cleaning a reaction substance without water washing. When taking out with a crystal | crystallization, a crystal | crystallization is deposited by dripping a reaction liquid in a lot of water. When the reaction is carried out under basic conditions, the produced phenolic compound of the present invention may dissolve in water, so that it is precipitated as crystals under neutral to acidic conditions by adding hydrochloric acid or the like.

Next, the epoxy resin mixture of the present invention will be described.
The epoxy resin mixture of the present invention has a low molecular weight area ratio in gel permeation chromatography (GPC) of usually 0.5 to 5 area% or less, preferably 1.0 to 5 area% or less. Preferably it is 2-5 area% or less. When the present invention is produced, when the low molecular weight component is 0.5 area% or less, the crystallinity of the epoxy resin is too high, and thus the solvent solubility tends to be inferior. When the low molecular weight component is 5% by area or more, there are many decomposition products and the thermal conductivity of the cured product is lowered.
In addition, although the low molecular weight body is included in the epoxy resin mixture of this invention on a certain basis, a low molecular weight body represents the sum total of the epoxidized material of said Formula (1) and said Formula (2).

（式（３）中、Ｒ_１、Ｒ_２、ｋ、ｌは下記と同じ意味を表し、Ｙはオキシグリシジル基又は下記式（４）

（式（４）中、Ｒ_３は水素原子、炭素数１〜６のアルキル基を表す。）
を表し、Ｙのうち少なくとも一つは上記式（４）である。）
で表される樹脂を３〜２０面積％含有する。当該エポキシ樹脂が含有されていることにより、高い溶剤溶解性を確保することができる。
本発明のエポキシ樹脂混合物中、上記式（３）の含有割合はＧＰＣ測定において、通常３．１〜２０面積％であり、好ましくは４〜１３面積％である。
また、Ｒ_３は炭素数１〜３のアルキル基が好ましく、メチル基がより好ましい。 The epoxy resin mixture of the present invention is obtained by the following formula (3) in gel permeation chromatography (GPC).

(In the formula (3), R ₁ , R ₂ , k, and l have the same meaning as described below, and Y represents an oxyglycidyl group or the following formula (4).

(In formula (4), R ₃ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
And at least one of Y is represented by the above formula (4). )
3-20 area% of resin represented by these is contained. By containing the epoxy resin, high solvent solubility can be ensured.
In the epoxy resin mixture of the present invention, the content ratio of the above formula (3) is usually 3.1 to 20% by area, preferably 4 to 13% by area in GPC measurement.
R ₃ is preferably an alkyl group having 1 to ₃ carbon atoms, and more preferably a methyl group.

The epoxy resin mixture of the present invention can be obtained by reacting the phenol compound (a) obtained by the above method with an epihalohydrin in an alcohol solvent and epoxidizing it. In the case of epoxidation, only one type of phenol compound (a) may be used or two or more types may be used in combination. Moreover, you may use together phenolic compounds other than phenolic compound (a) with phenolic compound (a).
As the phenolic compound other than the phenolic compound (a) that can be used in combination, any phenolic compound that is usually used as a raw material for epoxy resin can be used without particular limitation, but the effect of the present invention that the cured product has high thermal conductivity. The amount of the phenol compound that can be used in combination is preferably as small as possible, and it is particularly preferable to use only the phenol compound (a).
As the epoxy resin of the present invention, a compound represented by the formula (2) and a compound represented by the formula (1) are obtained because they exhibit a particularly excellent solvent solubility and a cured product having high thermal conductivity. The epoxidized product of the phenol compound (a) obtained by the reaction with is preferable.

  In the reaction for obtaining the epoxy resin mixture of the present invention, epichlorohydrin, α-methylepichlorohydrin, β-methylepichlorohydrin, epibromohydrin, and the like can be used as the epihalohydrin, and epichlorohydrin which is easily available industrially is preferable. The usage-amount of epihalohydrin is 2-20 mol normally with respect to 1 mol of hydroxyl groups of a phenol compound (a), Preferably it is 2-15 mol, Most preferably, it is 2-4.5 mol. The epoxy resin is obtained by a reaction in which a phenol compound and an epihalohydrin are added in the presence of an alkali metal oxide, and then the resulting 1,2-halohydrin ether group is opened to epoxidize. At this time, by using epihalohydrin in an amount significantly smaller than usual as described above, the molecular weight of the epoxy resin can be increased and the molecular weight distribution can be broadened. As a result, the resulting epoxy resin can be removed from the system as a resinous material having a relatively low softening point, and exhibits excellent solvent solubility.

  In addition, during the epoxidation, it is preferable for the reaction to proceed by adding an aprotic polar solvent such as alcohols such as methanol, ethanol and isopropyl alcohol, dimethyl sulfone, dimethyl sulfoxide, tetrahydrofuran and dioxane. Among these, alcohols are preferable, and the ionic reaction during epoxidation can be efficiently advanced depending on the polarity of the alcohol solvent, and an epoxy resin can be obtained with high purity. Furthermore, in the mesogenic group-containing epoxy resin of the present invention, the α, β-unsaturated carbonyl moiety shows high reactivity and tends to be decomposed, but since it is solvated by using an alcohol solvent, the decomposition reaction It becomes difficult to receive. As the alcohol solvent that can be used, methanol, ethanol, and isopropyl alcohol are preferable. Among these, it is particularly preferable to use methanol from the viewpoint of compatibility with the epoxy resin.

  When using the said alcohol, the usage-amount is 2-50 mass% normally with respect to the usage-amount of an epihalohydrin, Preferably it is 4-35 mass%. Moreover, when using an aprotic polar solvent, it is 5-100 mass% normally with respect to the usage-amount of epihalohydrin, Preferably it is 10-80 mass%.

Examples of the alkali metal hydroxide that can be used for the epoxidation reaction include sodium hydroxide, potassium hydroxide, and the like, and these may be used as they are, or an aqueous solution thereof may be used. When using an aqueous solution, the aqueous solution of the alkali metal hydroxide is continuously added to the reaction system and separated from a mixture of water and epihalohydrin distilled continuously under reduced pressure or normal pressure. Alternatively, water may be removed and only the epihalohydrin is continuously returned to the reaction system. The usage-amount of an alkali metal hydroxide is 0.9-3.0 mol normally with respect to 1 mol of hydroxyl groups of the phenolic compound of this invention, Preferably it is 1.0-2.5 mol, More preferably, it is 1.0- The amount is 2.0 mol, particularly preferably 1.0 to 1.3 mol.
Further, the present inventors remarkably reduce the amount of halogen contained in the epoxy resin obtained by using flaky sodium hydroxide in the epoxidation reaction, rather than using sodium hydroxide as an aqueous solution. It came to know that it became possible. This halogen is derived from epihalohydrin, and the more it is mixed in the epoxy resin, the lower the thermal conductivity of the cured product. Further, the flaky sodium hydroxide is preferably added in portions in the reaction system. By performing the divided addition, it is possible to prevent a rapid decrease in the reaction temperature, thereby preventing the formation of impurities such as 1,3-halohydrin and halomethylene, and a cured product with higher thermal conductivity. Can be formed.

  In order to accelerate the epoxidation reaction, it is preferable to add a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, trimethylbenzylammonium chloride as a catalyst. The amount of the quaternary ammonium salt used is usually 0.1 to 15 g, preferably 0.2 to 10 g, per 1 mol of the hydroxyl group of the phenol compound of the present invention.

The reaction temperature is usually 30 to 90 ° C, preferably 35 to 80 ° C. The reaction time is usually 0.5 to 10 hours, preferably 1 to 8 hours. Especially, when an alcohol solvent is used, 50 to 90 ° C is preferable, 60 to 85 ° C is more preferable, and 70 to 80 ° C is particularly preferable.
After completion of the reaction, the reaction product is washed with water or without washing with water, and the epihalohydrin, the solvent and the like are removed from the reaction solution under heating and reduced pressure. In order to further reduce the amount of halogen contained in the obtained epoxy resin, the recovered epoxy resin of the present invention is dissolved in a solvent such as toluene or methyl isobutyl ketone, and an alkali metal such as sodium hydroxide or potassium hydroxide. The reaction can be carried out by adding an aqueous solution of hydroxide to ensure ring closure. In this case, the usage-amount of an alkali metal hydroxide is 0.01-0.3 mol normally with respect to 1 mol of hydroxyl groups of the phenolic compound of this invention, Preferably it is 0.05-0.2 mol. The reaction temperature is usually 50 to 120 ° C., and the reaction time is usually 0.5 to 2 hours.

  After completion of the reaction, the produced salt is removed by filtration, washing with water, and the like, and the solvent is distilled off under heating and reduced pressure to obtain the epoxy resin of the present invention. Moreover, when the epoxy resin mixture of this invention precipitates as a crystal | crystallization, after melt | dissolving the salt produced | generated in a lot of water, you may collect the crystal | crystallization of the epoxy resin mixture of this invention by filtration.

  As described above, the total halogen content of the epoxy resin mixture of the present invention obtained using flaky sodium hydroxide is usually 1800 ppm or less, preferably 1600 ppm or less, more preferably 1300 ppm or less. If the total halogen content is too large, the electrical reliability of the cured product will be adversely affected, and it will remain as an uncrosslinked end, so the orientation of the molecules in the molten state during curing will not proceed and the thermal conductivity Leading to a decline.

  In the epoxy resin mixture thus obtained, the epoxy equivalent is preferably 176 to 300 g / eq, more preferably 176 to 250 g / eq, and particularly preferably 176 to 223 g / eq. The softening point is preferably 50 ° C. or higher, and particularly preferably 57 ° C. or higher.

  Hereinafter, the epoxy resin composition of the present invention will be described. The epoxy resin composition of the present invention contains at least one of the epoxy resin mixture of the present invention and the phenol compound of the present invention as an essential component.

  In the epoxy resin composition of the present invention, the epoxy resin mixture of the present invention can be used alone or in combination with other epoxy resins.

Specific examples of other epoxy resins include bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, bisphenol I, etc.) and phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted) Naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene and dihydroxynaphthalene) and various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.) Of polycondensates with benzene, aromatic compounds such as xylene and formaldehyde Polycondensates of compounds and phenols, phenols and various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene and isoprene Etc.), polycondensates of phenols and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.), phenols and aromatic dimethanols (benzene dimethanol, biphenyl dimethanol, etc.) Polycondensates, phenols and aromatic dichloromethyls (α, α'-dichloroxylene, bischloromethylbiphenyl etc.), phenols and aromatic bisalkoxymethyls Polycondensates with bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc., polycondensates of bisphenols and various aldehydes, and glycidyl ether epoxy resins obtained by glycidylation of alcohols, alicyclic An epoxy resin, a glycidylamine-based epoxy resin, a glycidyl ester-based epoxy resin, and the like can be mentioned, but the epoxy resin is not limited to these as long as it is a commonly used epoxy resin. These may be used alone or in combination of two or more.
When other epoxy resins are used in combination, the proportion of the epoxy resin mixture of the present invention in the total epoxy resin component in the epoxy resin composition of the present invention is preferably 30% by mass or more, more preferably 40% by mass or more, and 70% by mass. % Or more is more preferable, and 100% by mass (when no other epoxy resin is used in combination) is particularly preferable. However, when using the epoxy resin of this invention as a modifier of an epoxy resin composition, it adds in the ratio used as 1-30 mass% in all the epoxy resins.

Examples of the curing agent that can be used in the epoxy resin composition of the present invention include amine compounds, acid anhydride compounds, amide compounds, and phenol compounds. Specific examples of these other curing agents are shown in the following (a) to (e).
(A) Amine-based compounds diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, naphthalenediamine, etc. (b) acid anhydride-based compounds phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride , Tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, etc. (c) Amide compounds Dicyandiamide or linolenic acid dimer and ethylenediamine Polyamide resin, etc.

(D) Phenol compound polyhydric phenols (bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, terpene diphenol, 4,4′-dihydroxybiphenyl, 2,2′-dihydroxybiphenyl, 3,3 ′, 5, 5'-tetramethyl- (1,1'-biphenyl) -4,4'-diol, hydroquinone, resorcin, naphthalenediol, tris- (4-hydroxyphenyl) methane and 1,1,2,2-tetrakis (4 -Hydroxyphenyl) ethane and the like; phenols (eg, phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene and dihydroxynaphthalene) and aldehydes (formaldehyde, acetaldehyde, benzaldehyde, p-hydro) Phenol resins obtained by condensation with benzaldehyde, o-hydroxybenzaldehyde, furfural, etc.), ketones (p-hydroxyacetophenone, o-hydroxyacetophenone, etc.), or dienes (dicyclopentadiene, tricyclopentadiene, etc.); Phenols and substituted biphenyls (such as 4,4′-bis (chloromethyl) -1,1′-biphenyl and 4,4′-bis (methoxymethyl) -1,1′-biphenyl), or substituted phenyls ( Phenol resins obtained by polycondensation with 1,4-bis (chloromethyl) benzene, 1,4-bis (methoxymethyl) benzene, 1,4-bis (hydroxymethyl) benzene and the like; Or a modified product of the phenol resin; Lumpur A and halogenated phenols such as brominated phenol resin (e) Other imidazoles, BF ₃ ^- amine complex, guanidine derivatives

Among these other curing agents, active hydrogen such as amine compounds such as diaminodiphenylmethane, diaminodiphenylsulfone and naphthalenediamine, and condensates of catechol with aldehydes, ketones, dienes, substituted biphenyls or substituted phenyls. A curing agent having a structure in which groups are adjacent is preferable because it contributes to the arrangement of the epoxy resin.
Other curing agents may be used alone or in combination. When another curing agent is used in combination, the proportion of the phenolic compound of the present invention in the total curing agent component in the epoxy resin composition of the present invention is preferably 20% by mass or more, more preferably 30% by mass or more, and 70% by mass. The above is more preferable, and 100% by mass (when no other curing agent is used in combination) is particularly preferable.
In the epoxy resin composition of the present invention, the amount of the total curing agent containing the phenol compound of the present invention is preferably 0.5 to 2.0 equivalents relative to 1 equivalent of the epoxy groups of all epoxy resins, and is preferably 0.6 to 1.5 equivalents are particularly preferred.

If necessary, a curing accelerator may be added to the epoxy resin composition of the present invention. Specific examples of the curing accelerator include triphenylphosphine, bis (
Methoxyphenyl) Phosphine such as phenylphosphine, 2-methylimidazole, 2-ethylimidazole, imidazoles such as 2-ethyl, 4-methylimidazole, 2- (dimethylaminomethyl) phenol, trisdimethylaminomethylphenol, dia Tertiary amines such as zabicycloundecene, quaternary ammonium salts such as tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, triphenylbenzylphosphonium salt, triphenylethyl Quaternary phosphonium salts such as phosphonium salt and tetrabutylphosphonium salt (counter ion of quaternary salt is not particularly specified, such as halogen, organic acid ion, hydroxide ion, etc. Acid ion, a hydroxide ion.), Metal compounds such as tin octylate and the like.
The usage-amount of a hardening accelerator is 0.2-5.0 weight part normally per 100 weight part of epoxy resins, Preferably, it is 0.2-4.0 weight part.

The epoxy resin composition of the present invention can impart further excellent high heat conductivity to the cured product by containing an inorganic filler excellent in heat conduction as required.
The inorganic filler contained in the epoxy resin composition of the present invention is added for the purpose of imparting higher thermal conductivity to the cured product of the epoxy resin composition, and the thermal conductivity of the inorganic filler itself is too low. In some cases, the high thermal conductivity obtained by the combination of the epoxy resin and the curing agent may be impaired. Therefore, as the inorganic filler contained in the epoxy resin composition of the present invention, the one having higher thermal conductivity is preferable, usually 20 W / m · K or more, preferably 30 W / m · K or more, more preferably 50 W / m. -There is no restriction as long as it has a thermal conductivity of K or higher. In addition, heat conductivity here is the value measured by the method based on ASTM E1530. Specific examples of inorganic fillers having such characteristics include inorganic powder fillers such as boron nitride, aluminum nitride, silicon nitride, silicon carbide, titanium nitride, zinc oxide, tungsten carbide, alumina, magnesium oxide, synthetic fibers, Examples thereof include fibrous fillers such as ceramic fibers, and coloring agents. The shape of these inorganic fillers may be any of powder (bulk shape, spherical shape), single fiber, long fiber, etc. However, in particular, if it is a flat plate, the cured product is cured by the lamination effect of the inorganic filler itself. This is preferable because the thermal conductivity becomes higher and the heat dissipation of the cured product is further improved.
Although the usage-amount of the inorganic filler in the epoxy resin composition of this invention is 2-1000 mass parts normally with respect to 100 mass parts of resin components in an epoxy resin composition, in order to raise heat conductivity as much as possible. It is preferable to increase the amount of the inorganic filler as much as possible as long as the handling of the epoxy resin composition of the present invention in a specific application is not hindered. These inorganic fillers may be used alone or in combination of two or more.

  In addition, if the thermal conductivity of the entire filler can be maintained at 20 W / m · K or more, the thermal conductivity of the inorganic filler with 20 W / m · K or more is less than 20 W / m · K. However, for the purpose of the present invention to obtain a cured product having as high a thermal conductivity as possible, the use of a filler having a thermal conductivity of less than 20 W / m · K is minimal. Should be kept on. There is no particular limitation on the type and shape of the filler that can be used in combination.

  When the epoxy resin composition of the present invention is used for semiconductor sealing applications, heat conduction is performed at a ratio of 75 to 93% by mass in the epoxy resin composition in terms of heat resistance, moisture resistance, mechanical properties, etc. of the cured product. It is preferable to use an inorganic filler having a rate of 20 W / m · K or more. In this case, the balance is an epoxy resin component, a curing agent component, and other additives that are added as necessary. Examples of the additive include other inorganic fillers that can be used in combination and a curing accelerator that will be described later.

  The epoxy resin composition of the present invention may contain a curing accelerator. Examples of the curing accelerator that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole and 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, triethylenediamine, Tertiary amines such as triethanolamine and 1,8-diazabicyclo (5,4,0) undecene-7, organic phosphines such as triphenylphosphine, diphenylphosphine and tributylphosphine, metal compounds such as tin octylate, Tetrasubstituted phosphonium tetrasubstituted borates such as tetraphenylphosphonium tetraphenylborate and tetraphenylphosphonium ethyltriphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate and N Such as tetraphenyl boron salts such methylmorpholine tetraphenylborate and the like. 0.01-15 mass parts is used for a hardening accelerator as needed with respect to 100 mass parts of epoxy resins.

  If necessary, various compounding agents such as a silane coupling agent, a release agent and a pigment, various thermosetting resins, various thermoplastic resins, and the like can be added to the epoxy resin composition of the present invention. Specific examples of thermosetting resins and thermoplastic resins include vinyl ester resins, unsaturated polyester resins, maleimide resins, cyanate resins, isocyanate compounds, benzoxazine compounds, vinyl benzyl ether compounds, polybutadiene and its modified products, and acrylonitrile. Examples include modified polymers, indene resins, fluororesins, silicone resins, polyetherimides, polyethersulfones, polyphenylene ethers, polyacetals, polystyrenes, polyethylenes, and dicyclopentadiene resins. The thermosetting resin or thermoplastic resin is used in an amount occupying 60% by mass or less in the epoxy resin composition of the present invention.

The epoxy resin composition of the present invention can be obtained by uniformly mixing the above-mentioned components, and preferred applications thereof include semiconductor encapsulants and printed wiring boards.
The epoxy resin composition of the present invention can be easily made into a cured product by the same method as conventionally known. For example, an epoxy resin that is an essential component of the epoxy resin composition of the present invention, a curing agent, an inorganic filler having a thermal conductivity of 20 W / m · K or more, and a curing accelerator, a compounding agent, and various thermosetting resins as necessary. And various thermoplastic resins, etc., if necessary, using an extruder, kneader or roll, etc., until the mixture is sufficiently mixed until uniform, the melt casting method or transfer molding A cured product of the epoxy resin composition of the present invention can be obtained by molding by a method, an injection molding method, a compression molding method, or the like, and further heating for 2 to 10 hours above the melting point. By sealing the semiconductor element mounted on the lead frame or the like by the above-described method, the epoxy resin composition of the present invention can be used for semiconductor sealing applications.

Moreover, the epoxy resin composition of this invention can also be made into the varnish containing a solvent. The varnish includes, for example, at least one of the epoxy resin of the present invention or the phenol resin of the present invention in at least one of an epoxy resin and a curing agent, and if necessary, has a thermal conductivity of 20 W / m · K or more. Mixtures containing other components such as inorganic fillers, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, N, N′-dimethylformamide, N, N′-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether Glycol ethers such as Tell, ethyl acetate, butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, propylene glycol monomethyl ether acetate, dialkyl glutarate, dialkyl succinate, dialkyl adipate, It can be obtained by mixing with a cyclic ester such as γ-butyrolactone, an organic solvent such as petroleum ether such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha and solvent naphtha. The amount of the solvent is usually 10 to 95% by mass, preferably 15 to 85% by mass with respect to the whole varnish.
The varnish obtained as described above is impregnated into a fiber substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber and paper, and then the solvent is removed by heating, and the epoxy resin composition of the present invention By making a semi-cured state, the prepreg of the present invention can be obtained. Here, the “semi-cured state” means a state in which an epoxy group which is a reactive functional group partially remains unreacted. The prepreg can be hot press molded to obtain a cured product.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. In the synthesis examples, examples, and comparative examples, “part” means “part by mass”.
The epoxy equivalent, melting point, softening point, total chlorine content, and thermal conductivity were measured under the following conditions.
-Epoxy equivalent Measured by the method described in JIS K-7236, the unit is g / eq. It is.
Melting point Seiko Instruments Inc. EXSTAR6000 made
Measurement sample 2 mg to 5 mg Temperature rising rate 10 ° C./min.
-Softening point It measures by the method based on JISK-7234, and a unit is (degreeC).
・ GPC (gel permeation chromatography)
Manufacturer: Tosoh Corporation Column: H _XL -L (1), G3000H _XL (1), G2000H _XL (2)
Flow rate: 1.065 ml / min.
Column temperature: 40 ° C
Solvent: THF (tetrahydrofuran)
Detector: UV (254 nm) and total chlorine amount Add 1N-KOH propylene glycol solution to butyl carbitol solution of sample, and measure the amount of chlorine released (mol) by refluxing for 10 minutes by silver nitrate titration method. The value divided by the weight of.
-Thermal conductivity It measures by the method based on ASTM E1530, and a unit is W / m * K.

Synthesis example 1
A flask equipped with a stirrer, a reflux condenser, and a stirrer was charged with 136 parts of 4′-hydroxyacetophenone, 152 parts of vanillin and 200 parts of ethanol and dissolved. After adding 20 parts of 97% by mass sulfuric acid to this, 60 ° C.
The reaction solution was poured into 1200 parts of water and allowed to crystallize. The crystals were separated by filtration, washed twice with 600 parts of water, and then vacuum-dried to obtain 256 parts of phenol compound 1 as yellow crystals. The endothermic peak temperature of the obtained crystal as measured by DSC was 233 ° C.

Example 1
While purging a flask equipped with a stirrer, a reflux condenser, and a stirrer, 141 parts of phenol compound 1 obtained in Synthesis Example 1, 291 parts of epichlorohydrin, 29 parts of methanol, and 9 parts of water were added and stirred. The mixture was heated to 75 ° C., dissolved, 45 parts of flaky sodium hydroxide was added in portions over 90 minutes, and the reaction was carried out for 1 hour at 75 ° C. After completion of the reaction, 109 parts of epichlorohydrin was added and washed with water to remove salt. Subsequently, excess solvent such as epichlorohydrin was distilled off under reduced pressure at 140 ° C. using a rotary evaporator. The residue was dissolved in 400 parts of methyl isobutyl ketone (hereinafter referred to as MIBK), washed with water to remove salts, and then the MIBK solution was heated to 75 ° C. and 28 parts of 30% aqueous sodium hydroxide solution was added with stirring. Then, after reacting for 75 minutes, washing was performed until the washing water became neutral. The obtained solution was distilled off MIBK and the like under reduced pressure at 180 ° C. using a rotary evaporator to obtain 68 parts of an epoxy resin mixture (hereinafter referred to as epoxy resin 1). The epoxy equivalent of the obtained epoxy resin 1 is 221 g / eq. The softening point was 57 ° C. The area ratio of the low molecular weight body in gel permeation chromatography (GPC) was 2.9 area%, and the area ratio of the resin represented by the above formula (3) was 7.6 area%.

(Comparative Example 1)
While purging a flask equipped with a stirrer, a reflux condenser, and a stirrer with nitrogen purge, 177 parts of phenol compound 1 obtained in Synthesis Example 1, 363 parts of epichlorohydrin, 182 parts of dimethyl sulfoxide (hereinafter, DMSO), 4 parts of water was added, the temperature was raised to 70 ° C. with stirring, the mixture was dissolved, 56 parts of flaky sodium hydroxide was added in portions over 90 minutes, and then 70 ° C.
The reaction was carried out for 3 hours. After completion of the reaction, 363 parts of epichlorohydrin was added to the reaction solution and washed with water. The organic layer after washing with water was distilled off excess solvent such as epichlorohydrin under reduced pressure at 135 ° C. using a rotary evaporator. The residue was dissolved in 382 parts of methyl isobutyl ketone (hereinafter referred to as MIBK) and then washed with water to remove the salt. After washing with water, the MIBK solution was heated to 75 ° C., added with 17 parts of 30% aqueous sodium hydroxide solution with stirring, reacted for 1 hour, and then washed with water until the washing water became neutral. 200 parts of epoxy resin 2 was obtained by distilling MIBK etc. off under reduced pressure using a rotary evaporator at 180 ° C. The epoxy equivalent of the obtained epoxy resin mixture (hereinafter referred to as epoxy resin 2) was 217 g / eq. The softening point was 55 ° C. The area ratio of the low molecular weight substance in gel permeation chromatography (GPC) was 7.6 area%, and the area ratio of the resin represented by the above formula (3) was 3.0 area%.

(Examples 2 and 3, Comparative Examples 2 and 3)
Various components are blended in the proportions (parts) shown in Table 1, kneaded with a mixing roll, converted into a tablet, a resin molded product is prepared by transfer molding, and heated at 160 ° C. for 2 hours and further at 180 ° C. for 8 hours. Hardened | cured material of the epoxy resin composition of invention and the resin composition for a comparison was obtained. The results of measuring the thermal conductivity of these cured products are shown in Table 1.

(Solubility test)
The solubility of various epoxy resins including epoxy resins 1 and 2 obtained by these operations in methyl isobutyl ketone, methyl ethyl ketone (hereinafter referred to as MEK) and cyclohexanone at 60 ° C. at 30%, 40% and 50% respectively. It is shown in Table 2.

  From the above results, since the epoxy resin obtained in the present invention is highly pure, the cured product exhibits high thermal conductivity, and in particular, electrical / electronic such as IC sealing materials, laminated materials, electrical insulating materials, etc. Useful in the field.

Claims (6)

Among the epoxy resins obtained by going through the following steps (a) to (b), the total area ratio of the epoxidized products of the following formulas (1) and (2) in GPC is measured by high performance liquid chromatography. 0.5 to 5 area%, the following formula (3)

(In the formula (3), R ₁ , R ₂ , k, and l have the same meaning as described below, and Y represents an oxyglycidyl group or the following formula (4).

(In formula (4), R ₃ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
And at least one of Y is represented by the above formula (4). )
The epoxy resin mixture which contains 3.1-20 area% in the measurement by high performance liquid chromatography.
Process (I): following formula (1)

(In Formula (1), each R ₁ is independently present and is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a hydroxyl group, Represents either a nitro group or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, l represents the number of R ₁ , and is an integer of 0 to 4);
Following formula (2)

(In Formula (2), each R ₂ is independently present, a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a hydroxyl group, It represents any of a nitro group, a formyl group, an allyl group, or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, where k represents the number of R ₂ and is an integer of 0 to 4. A step of obtaining a phenol compound (a) by reaction with a compound.
Step (b): A step of obtaining the epoxy resin of the present invention by reacting the phenol compound (a) obtained in step (a) with epihalohydrin by a known method. An epoxy resin composition comprising the epoxy resin according to claim 1 and a curing agent and / or a curing accelerator. The epoxy resin composition according to claim 2, comprising an inorganic filler having a thermal conductivity of 20 W / m · K or more. The epoxy resin composition of Claim 2 or Claim 3 used for a semiconductor sealing use. A prepreg comprising the epoxy resin composition according to claim 2 or 3 and a sheet-like fiber base material. Hardened | cured material formed by hardening | curing the epoxy resin composition as described in any one of Claims 2-4, or the prepreg of Claim 5.