Phenol mixtures, epoxy resins, epoxy resin compositions, cured products, and electrical and electronic components

Abstract

The present invention addresses the problem of providing: a phenol mixture that is optimal as an epoxy resin production raw material and that is capable of realizing the high heat resistance required in recent years; and an epoxy resin, an epoxy resin composition, a cured product, and an electrical / electronic component that use the phenol mixture. The problem is solved by: a phenol mixture containing 3,3',5,5'-tetramethyl-4,4'-biphenol as a main component, wherein the phenol mixture contains more than 0.3 wt% but less than 10.0 wt% of polyphenylene ether, and contains 1.3-4.0 wt% of tetramethyldiphenoquinone; and an epoxy resin, an epoxy resin composition, a cured product, and an electrical / electronic component that use the phenol mixture.

Description

Technical Field

[0001] The present invention relates to a phenol mixture, and more particularly, to a phenol mixture as a raw material for producing an epoxy resin limited to a specific composition, an epoxy resin using the same, an epoxy resin composition, a cured product, and an electric and electronic component, in order to provide an epoxy resin having excellent heat resistance.

Background Art

[0002] Epoxy resins are generally cured with various curing agents to form cured products having excellent mechanical properties, heat resistance, electrical properties, etc., and are thus used in a wide range of fields such as adhesives, paints, and electric and electronic materials. In particular, among the fields of electric and electronic materials, in the application of semiconductor encapsulation materials, tetramethylbiphenyl-type epoxy resins are widely used because they can provide encapsulation materials with high added value.

[0003] With the remarkable technological development of semiconductors in recent years, elements such as SiC and GaN have been used in next-generation power semiconductors. However, since these are used at higher temperatures than the current mainstream Si elements, there is a particular demand for improving heat resistance so that the encapsulation material, which is a protective member, can withstand a high-temperature environment.

[0004] Tetramethylbiphenyl-type epoxy resins can generally be obtained by subjecting raw material biphenol and epihalohydrin to a condensation reaction. As one of the raw materials for tetramethylbiphenyl-type epoxy resins, 3,3',5,5'-tetramethyl-4,4'-biphenol (hereinafter sometimes abbreviated as TMBPL) is known. Patent Documents 1 to 3 describe 3,3',5,5'-tetramethyl-4,4'-biphenol having a specific impurity content within a specific range and a method for producing the same, and it is described that a tetramethylbiphenyl-type epoxy resin was produced by reacting the TMBPL with epichlorohydrin.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2003-327554 [Patent Document 2] Japanese Patent Publication No. 2004-2830 [Patent Document 3] Japanese Patent Application Publication No. 61-268641 [Overview of the project] [Problems that the invention aims to solve]

[0006] In tetramethylbiphenol-type epoxy resins using TMBPL described in Patent Documents 1 to 3, the glass transition temperature (Tg) and 5% weight loss temperature of the cured product using the epoxy resin or epoxy resin composition tended to be low, resulting in poor heat resistance. The object of the present invention is to provide a phenol mixture that is optimal as a raw material for epoxy resin production that can achieve the high heat resistance required in recent years, as well as epoxy resins, epoxy resin compositions, cured products, and electrical and electronic components using the same. [Means for solving the problem]

[0007] In order to solve the above problems, the present inventors conducted diligent research and found that 3,3',5,5'-tetramethyl-4,4'-biphenol contains various by-components generated during its manufacturing process. Conventionally, efforts were made to minimize these by-components by optimizing reaction conditions and purification, but the inventors discovered that epoxy resins obtained using 3,3',5,5'-tetramethyl-4,4'-biphenol with specific by-components present in specific amounts exhibit excellent heat resistance, thus completing the present invention.

[0008] In other words, the gist of the present invention lies in the following [1] to [8]. [1] A phenol mixture having 3,3',5,5'-tetramethyl-4,4'-biphenol as the main component, and containing more than 0.3% by weight and less than 10.0% by weight of polyphenylene ether. [2] The phenol mixture according to [1] further containing 1.3% to 4.0% by weight of tetramethyldiphenoquinone. [3] An epoxy resin obtained by reacting the phenol mixture described in [1] or [2] with an epihalohydrin. [4] An epoxy resin composition comprising 0.01 to 1000 parts by weight of a curing agent per 100 parts by weight of the epoxy resin described in [3]. [5] The epoxy resin composition according to [4], wherein the curing agent is at least one selected from the group consisting of phenolic curing agents, amine curing agents, tertiary amines, acid anhydride curing agents, amide curing agents, and imidazoles. [6] The epoxy resin composition according to [4] or [5], further comprising an epoxy resin different from the epoxy resin in the epoxy resin composition. A cured product obtained by curing any of the epoxy resin compositions described in [7] [4] to [6]. Electrical and electronic components obtained by curing the epoxy resin composition described in any of [8] [4] to [6]. [Effects of the Invention]

[0009] According to the present invention, it is possible to obtain an epoxy resin cured product with higher heat resistance compared to conventional epoxy resin cured products using TMBPL. Therefore, the phenol mixture according to one embodiment of the present invention and the epoxy resin obtained using the same can be used as an optimal raw material for the production of tetramethylbiphenol type epoxy resin. Furthermore, it is expected that epoxy resin compositions containing this epoxy resin, cured products obtained by curing them, and electrical and electronic components such as semiconductor encapsulants containing this epoxy resin can be used continuously in a temperature range higher than that in conventional applications. [Modes for carrying out the invention]

[0010] The embodiments of the present invention will be described in detail below, but the following description is merely one example of an embodiment of the present invention, and the present invention is not limited to the following description unless it exceeds the gist of the invention. In this specification, when the expression "~" is used, it is used to mean an expression that includes the numerical value or physical property value before and after it.

[0011] [Phenol mixture] The phenol mixture according to the first embodiment of the present invention is a phenol mixture mainly composed of 3,3',5,5'-tetramethyl-4,4'-biphenol, containing more than 0.3% by weight and less than 10.0% by weight of polyphenylene ether (hereinafter sometimes abbreviated as PPE), and containing 1.3 to 4.0% by weight of tetramethyldiphenoquinone (hereinafter sometimes abbreviated as DPQ).

[0012] The phenol mixture of this embodiment is referred to as a "phenol mixture" because it contains TMBPL as the main component and several minor components. However, a "mixture" consisting of TMBPL and other components obtained through a process not aimed at obtaining a phenol compound may also be included in the phenol mixture of this embodiment. In this industry, even mixtures that do not consist of a single component are sometimes simply referred to as "phenol" or "phenol compound" and sold as such.

[0013] The reason why the epoxy resin obtained using the phenol mixture of this embodiment exhibits excellent heat resistance is not clear, but the following can be inferred. In other words, it is presumed that by including a specific proportion of PPE, which has a relatively high molecular weight, in the phenol mixture of this embodiment, when the epoxy resin obtained using it is cured to form a cured product, it contributes in some way to an increase in the crosslinking density of the cured product, and as a result, it affects the improvement of heat resistance. The more PPE there is, the higher the crosslinking density of the cured product tends to be, and therefore the Tg and 5% weight loss temperature of the cured product tend to rise. Conversely, the less PPE there is, the lower the polymer component tends to be, and the lower the Tg and 5% weight loss temperature of the cured product tend to be.

[0014] Also, when the phenol mixture of the present embodiment contains DPQ, since the melting point of DPQ itself is 222°C and its boiling point is also expected to be high, by including DPQ at a specific ratio, when an epoxy resin obtained using it is cured to produce a cured product, it is considered that the Tg and the 5% weight loss temperature are sufficiently high, giving a cured product with excellent heat resistance. As the content of DPQ increases, the crosslink density increases, and the Tg and 5% weight loss temperature of the resulting cured product tend to improve. Also, as the content decreases, the Tg and 5% weight loss temperature of the cured product tend to decrease.

[0015] For the above reasons, the content of PPE is preferably 0.5% by weight to 8.0% by weight, more preferably 1.0% by weight to 7.5% by weight, and even more preferably 1.5% by weight to 5.0% by weight. The content of DPQ is preferably 1.5% by weight to 3.5% by weight, more preferably 2.0% by weight to 3.0% by weight.

[0016] The phenol mixture of the present embodiment has TMBPL as the main component. Specifically, "having as the main component" preferably means that TMBPL is contained at 80% by weight or more, more preferably 85% by weight or more, and even more preferably 90% by weight or more.

[0017] The phenol mixture of the present embodiment may contain a plurality of other sub-components in addition to the above-described main components TMBPL, PPE, and DPQ. The sub-components are not particularly limited, but preferably include 4-(2,6-dimethylphenoxy)-2,6-dimethylphenol (hereinafter may be abbreviated as ED) and 2,6-xylenol (hereinafter may be abbreviated as XNL).

[0018] When the phenol mixture contains ED, its content is not particularly limited, but is preferably 0.2% by weight or less, more preferably 0.1% by weight or less. When the content of ED with a monofunctional phenolic hydroxyl group is 0.2% by weight or less, when producing a cured product of an epoxy resin, the Tg and the 5% weight loss temperature are sufficiently high, giving a cured product with excellent heat resistance, so it is preferable. When the phenol mixture contains XNL, its content is not particularly limited, but is preferably 0.1 to 3.4% by weight, more preferably 0.3 to 2.5% by weight, and even more preferably 0.5 to 2.0% by weight. The less 2,6-xylenol with a monofunctional phenolic hydroxyl group, when producing a cured product of an epoxy resin, the Tg and the 5% weight loss temperature are sufficiently high, giving a cured product with excellent heat resistance. The more there is, the higher the productivity improvement in an industrial scale tends to be when producing the phenol mixture. The composition of the phenol mixture can be measured by the method described in the section of Examples below.

[0019] The second embodiment of the present invention is a phenol mixture mainly composed of 3,3',5,5'-tetramethyl-4,4'-biphenol, containing 1.3 to 4.0% by weight of DPQ and 0.1 to 3.4% by weight of XNL. The preferable ranges of the contents of 3,3',5,5'-tetramethyl-4,4'-biphenol, DPQ, and XNL are the same as those in the above aspect.

[0020] The third embodiment of the present invention is a phenol mixture mainly composed of 3,3',5,5'-tetramethyl-4,4'-biphenol, containing 0.2% by weight or less of ED and 0.1 to 3.4% by weight of XNL. The preferable ranges of the contents of 3,3',5,5'-tetramethyl-4,4'-biphenol, ED, and XNL are the same as those in the above aspect.

[0021] A fourth embodiment of the present invention is a phenol mixture mainly composed of 3,3',5,5'-tetramethyl-4,4'-biphenol, containing 0.2% by weight or less of ED and 1.3 to 4.0% by weight of DPQ. The preferred ranges of the content of 3,3',5,5'-tetramethyl-4,4'-biphenol, ED, and DPQ are the same as in the above embodiment.

[0022] [Method for producing phenol mixtures] There are no particular limitations on the method for producing the phenol mixtures of the first to fourth embodiments, but a typical production method includes a step of oxidative dimerization of 2,6-xylenol in an alkaline aqueous solvent containing a surfactant in the presence of a metal catalyst and an oxidizing agent.

[0023] The amount of water used as the reaction solvent is usually 0.5 to 10 kg, preferably 1 to 5 kg, per 1 kg of 2,6-xylenol. Examples of surfactants include fatty acid soaps, alkyl sulfonates, alkylbenzene sulfonic acid, and alkyl sulfates. Sodium lauryl sulfate is preferred. The amount of surfactant used is usually in the range of 0.01 to 50 mmol, preferably 0.1 to 10 mmol, per 1 mole of 2,6-xylenol.

[0024] Examples of alkaline substances include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate, bicarbonates, boron compounds such as sodium borate and borax, alkali metal phosphates such as sodium phosphate, sodium hydrogen phosphate, potassium phosphate, and potassium hydrogen phosphate, and amine bases such as triethylamine and pyridine. Among these, boron compounds are preferred in terms of yield and selectivity. Borax is particularly preferred. The amount of alkaline substance used is usually such that the pH of the reaction system is maintained in the range of 8 to 11.

[0025] Copper compounds are preferably used as metal catalysts. The copper compounds may be monovalent or divalent, and specific examples include copper halides, copper hydroxide, copper sulfate, copper nitrate, copper carboxylate, and alkyl copper sulfate. The amount of metal catalyst used is 0.005 to 0.1 mmol per mole of 2,6-xylenol. Preferably, it is 0.01 to 0.06 mmol.

[0026] As an oxidizing agent, oxygen gas or other oxygen-containing gases such as air can be used. Oxygen is preferably used. The amount of oxidizing agent used is in the range of 0.01 to 1 mole per mole of 2,6-xylenol. Preferably, it is 0.1 to 0.6 moles. By setting the amount of oxidizing agent to a specific range, the proportions of 4-(2,6-dimethylphenoxy)-2,6-dimethylphenol, tetramethyldiphenoquinone, and 2,6-xylenol in the phenol mixture can be set to a specific range. The reaction temperature is usually 50 to 100°C, and the reaction pressure is in the range of atmospheric pressure to 30 atmospheres, depending on the oxygen concentration in the gas phase. The reaction time is usually 1 to 24 hours, preferably 5 to 15 hours.

[0027] The following steps are preferably included after the step of oxidative dimerization of 2,6-xylenol: The resulting reaction solution is heated while maintaining a pH of 7.5 to 9.0, and water and unreacted 2,6-xylenol are removed by distillation. In this case, it is preferable to adjust the pH after replacing the reaction system with an inert gas such as nitrogen. The acid used for pH adjustment is not particularly limited, but mineral acids are generally used. Sulfuric acid or hydrochloric acid are particularly preferred. By setting the pH within the above range, the content of polyphenylene ether and other components can be kept within the specified range for each embodiment. The reaction pressure is not particularly limited, but can be carried out under atmospheric pressure or reduced pressure.

[0028] Next, an acid is added to the resulting solution to adjust the pH to 2-6.9, and then alcohol is added and mixed and stirred to obtain a mixed solution. Suitable alcohols include lower alcohols with 1-4 carbon atoms, such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and n-butanol. In this case, the weight ratio of alcohol to water is usually 1 / 1-10 / 1, preferably 2 / 1-5 / 1. Entrained water from the reaction slurry is used to prepare the mixed solution; however, if the phenol mixture is recovered as a solid, water is added. By keeping the mixing ratio of water to alcohol within the above range, the yield of the phenol mixture in the first to fourth embodiments can be maintained at a high level. The concentration of the phenol mixture in the mixture is usually 5 to 50% by weight. The temperature during mixing and stirring is usually 40 to 100°C, preferably 50 to 90°C. The mixing and stirring time is usually 0.1 to 5 hours, preferably 0.3 to 2 hours.

[0029] Next, the resulting mixture is separated into solid and liquid to recover the phenol mixture. Methods such as filtration and centrifugation are employed for solid-liquid separation. The temperature of the mixture during solid-liquid separation is typically 35-70°C, preferably 40-65°C. In addition, the phenol mixture can be recovered by heating or reduced pressure.

[0030] [Epoxy resin] An epoxy resin according to another embodiment of the present invention is an epoxy resin obtained by reacting a phenol mixture according to any one of the first to fourth embodiments of the present invention with an epihalohydrin. The epoxy resin of this embodiment is made from a phenol mixture according to any of the first to fourth embodiments of the present invention. However, PPE, DPQ, etc. in the phenol mixture may contribute to the reaction, remain unchanged without contributing to the reaction, or distill out of the system during the reaction. Therefore, it is difficult to identify the presence and form of PPE and DPQ contained in the phenol mixture in the resulting epoxy resin, or to determine the structure of the epoxy resin by analysis. In this embodiment, the epoxy resin may contain a repeating structure or a monomolecular structure, but in this industry, both types of epoxy compounds are sometimes referred to and sold simply as "epoxy resin." Furthermore, in this industry, a mixture containing epoxy resins different from those of this embodiment is sometimes simply called "epoxy resin."

[0031] [Epoxy equivalent] In this embodiment, the epoxy resin is preferably such that its epoxy equivalent is 186 to 189 g / equivalent (hereinafter sometimes referred to as g / eq) from the viewpoint of improving the heat resistance of the cured product obtained from the epoxy resin. It is believed that excellent curing properties can be obtained by setting the epoxy equivalent within the above specific range. The epoxy equivalent increases depending on the amount of epihalohydrin or alkali metal hydroxide used in the reaction. reduce do. In this invention, "epoxy equivalent" is defined as "the mass of epoxy resin containing one equivalent of epoxy groups," and can be measured in accordance with JIS K7236.

[0032] [Manufacturing method for epoxy resin] The method for producing the epoxy resin of this embodiment is not particularly limited, but one method is to react a phenol mixture according to any of the first to fourth embodiments of the present invention with an epihalohydrin in the presence of an alkali metal hydroxide. When producing epoxy resin in this manner, at least a phenol mixture according to any one of the first to fourth embodiments of the present invention and an epihalohydrin are used as raw materials. However, other polyvalent hydroxy compounds (hereinafter sometimes referred to as "other polyvalent hydroxy compounds") may also be used in combination to produce the epoxy resin. However, from the viewpoint of improving the heat resistance of the cured product obtained using the epoxy resin of this embodiment, it is preferable to use the phenol resin composition of this embodiment alone. Here, "polyvalent hydroxy compounds" refers to a general term for phenol compounds that have two or more hydroxyl groups.

[0033] Other polyhydric hydroxy compounds include bisphenol A, bisphenol F, bisphenol S, bisphenol AD, bisphenol AF, hydroquinone, resorcinol, methylresorcinol, biphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, thiodiphenols, phenol novolac resin, cresol novolac resin, phenol aralkyl resin, biphenyl aralkyl resin, naphthol aralkyl resin, terpene phenol resin, dicyclopentadiene phenol resin, bisphenol A novolac resin, and naphthol novolac resin. Examples include various polyhydric phenols such as brominated bisphenol A and brominated phenol novolac resins (excluding phenol mixtures according to any of the first to fourth embodiments of the present invention), polyhydric phenol resins obtained by condensation reactions of various phenols with various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, and glyoxal, polyhydric phenol resins obtained by condensation reactions of xylene resin and phenols, and various phenol resins such as co-condensation resins of heavy oil or pitch with phenols and formaldehydes. Preferred resins among these include phenol novolac resins, phenol aralkyl resins, polyhydric phenol resins obtained by the condensation reaction of phenol and hydroxybenzaldehyde, biphenyl aralkyl resins, and naphthol aralkyl resins.

[0034] The amount of epihalohydrin used is preferably 2 to 10.0 equivalents, and particularly 4 to 8 equivalents, per equivalent of hydroxyl groups of the total polyhydric hydroxy compounds, which are the sum of the phenol mixture used as raw materials and other polyhydric hydroxy compounds used as needed. It is preferable that the amount of epihalohydrin is above the lower limit, as this makes it easier to control the high molecular weight reaction and allows the resulting epoxy resin to have an appropriate epoxy equivalent. On the other hand, it is preferable that the amount of epihalohydrin is below the upper limit, as this tends to improve production efficiency. Epichlorohydrin or epibromohydrin are usually used as epihalohydrin, but in this embodiment, epichlorohydrin is preferred.

[0035] The amount of alkali metal hydroxide used is typically 0.8 to 1.6 equivalents, preferably 1.0 to 1.4 equivalents, per equivalent of hydroxyl groups in the total polyvalent hydroxy compound, which is the raw material for the epoxy resin. The alkali metal hydroxide in an amount equivalent to the above usage is added in solid or aqueous solution form and the reaction is carried out. It is preferable that the amount of alkali metal hydroxide is above the lower limit above, as this makes it difficult for unreacted hydroxyl groups to react with the resulting epoxy resin, and thus easier to control the high molecular weight reaction. It is also preferable that the amount of alkali metal hydroxide is below the upper limit above, as this makes it difficult for impurities to be generated by side reactions. Typical alkali metal hydroxides used here include sodium hydroxide and potassium hydroxide.

[0036] This reaction can be carried out under normal pressure or reduced pressure, and the reaction temperature is preferably 20 to 150°C, more preferably 30 to 100°C. A reaction temperature above the lower limit is preferable because it facilitates the reaction and makes it easier to control. A reaction temperature below the upper limit is preferable because it reduces the likelihood of side reactions and makes it particularly easier to reduce chlorine impurities.

[0037] The reaction may be carried out while dehydrating by azeotropizing the reaction mixture while maintaining a predetermined temperature as needed, cooling the volatile vapor to obtain a condensate, separating the oil / water from the oil, and returning the oil, from which the water has been removed, to the reaction system. To suppress the rapid reaction, alkali metal hydroxides are preferably added intermittently or continuously in small amounts over 0.1 to 8 hours, more preferably over 0.5 to 6 hours. It is preferable that the time spent adding alkali metal hydroxides is above the lower limit above, as this prevents the reaction from proceeding too rapidly and makes it easier to control the reaction temperature. It is preferable that the time spent adding the alkali metal hydroxides is below the upper limit above, as this makes it less likely for chlorine impurities to be generated, and is also preferable from an economic standpoint. After the reaction is complete, crude epoxy resin can be obtained by filtering off the insoluble by-product salts or removing them by washing with water, and then removing the unreacted epihalohydrins by distillation under reduced pressure.

[0038] Furthermore, catalysts such as quaternary ammonium salts including tetramethylammonium chloride and tetraethylammonium bromide, tertiary amines including benzyldimethylamine and 2,4,6-tris(dimethylaminomethyl)phenol, imidazoles including 2-ethyl-4-methylimidazole and 2-phenylimidazole, phosphonium salts including ethyltriphenylphosphonium iodide, and phosphines including triphenylphosphine may also be used in this reaction.

[0039] Furthermore, in this reaction, inert organic solvents such as alcohols like ethanol and isopropanol, ketones like acetone, methyl ethyl ketone, and methyl isobutyl ketone, ethers like dioxane and ethylene glycol dimethyl ether, glycol ethers like methoxypropanol, and aprotic polar solvents like dimethyl sulfoxide and dimethylformamide may be used.

[0040] The epoxy resin of this embodiment can be obtained by repurifying the crude epoxy resin produced as described above by reacting it again with an alkali metal hydroxide.

[0041] The alkali treatment conditions for producing the epoxy resin of this embodiment are described below. However, the reaction rate may vary depending on the conditions. Therefore, the desired epoxy resin can be obtained by taking samples at appropriate timings during the reaction and analyzing the epoxy equivalent.

[0042] In the reaction between epoxy resin and alkali metal hydroxide, an organic solvent may be used to dissolve the epoxy resin. While there are no particular restrictions on the organic solvent used in the reaction, it is preferable to use a ketone-based organic solvent from the viewpoint of manufacturing efficiency, handling, and workability. Furthermore, aprotic polar solvents may be used from the viewpoint of further reducing the amount of hydrolyzable chlorine. Examples of ketone-based organic solvents include methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Methyl isobutyl ketone is particularly preferred due to its ease of post-treatment. These may be used individually or in combination of two or more. Examples of aprotic polar solvents include dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, sulfolane, dimethylformamide, dimethylacetamide, and hexamethylphosphoramide. These may be used individually or in combination of two or more. Among these aprotic polar solvents, dimethyl sulfoxide is preferred because it is readily available and allows for easy reduction of hydrolyzable chlorine content.

[0043] When using a mixture of the above-mentioned ketone-based organic solvent and aprotic polar solvent, it is preferable to use them in such a way that the proportion of the aprotic polar solvent relative to the total is 1 to 80% by weight, preferably 5 to 30% by weight. The amount of solvent used is such that the concentration of epoxy resin in the liquid subjected to treatment with alkali metal hydroxide is typically 1 to 90% by weight, preferably 5 to 80% by weight.

[0044] Alkali metal hydroxides can be used in solid or solution form. Examples include potassium hydroxide and sodium hydroxide, with sodium hydroxide being preferred. Alternatively, alkali metal hydroxides may be used dissolved in organic solvents or water. Preferably, alkali metal hydroxides are used as a solution dissolved in water or an organic solvent. The amount of alkali metal hydroxide used is preferably 0.1 parts by weight or more and 20 parts by weight or less per 100 parts by weight of epoxy resin, calculated on a solid content basis. By using alkali metal hydroxide within this range, it is possible to adjust the epoxy equivalent of the resulting epoxy resin. When the amount of alkali metal hydroxide is within the above range, the epoxy resin of this embodiment is easily obtained. The reaction temperature is preferably 10 to 150°C, more preferably 20 to 90°C, and the reaction time is preferably 0.1 to 15 hours, more preferably 0.3 to 10 hours. When the reaction temperature is within the above range, the epoxy resin of this embodiment is easily obtained. After the reaction, excess alkali metal hydroxides and by-product salts can be removed by methods such as washing with water, and the organic solvent can be further removed by vacuum distillation and / or steam distillation to obtain the epoxy resin of this embodiment.

[0045] [Epoxy resin composition] An epoxy resin composition according to another embodiment of the present invention comprises at least the epoxy resin and curing agent according to the embodiment described above. In addition, the epoxy resin composition of this embodiment may optionally contain other epoxy resins other than the epoxy resin of this embodiment (hereinafter sometimes simply referred to as "other epoxy resins"), curing accelerators, inorganic fillers, coupling agents, etc. The epoxy resin composition of this embodiment, which includes the epoxy resin described above, provides a cured product that fully satisfies various physical properties required for various applications, such as excellent heat resistance.

[0046] [Hardening agent] In this invention, "curing agent" refers to a substance that contributes to the crosslinking reaction and / or chain length extension reaction between epoxy groups of an epoxy resin. In this invention, even substances that are normally called "curing accelerators" will be considered curing agents if they contribute to the crosslinking reaction and / or chain length extension reaction between epoxy groups of an epoxy resin. In the epoxy resin composition of this embodiment, the curing agent content is preferably 0.1 to 1000 parts by weight per 100 parts by weight of the total epoxy resin component as solid content. More preferably, it is 500 parts by weight or less, and even more preferably 300 parts by weight or less. In the present invention, "solid content" means the components excluding the solvent, and includes not only solid epoxy resin but also semi-solid and viscous liquid substances. The amount of "total epoxy resin component" is the amount of epoxy resin contained in the epoxy resin composition of this embodiment. If the epoxy resin composition of this embodiment contains only the epoxy resin according to one embodiment of the present invention, it corresponds to the amount of that epoxy resin. If it contains the epoxy resin according to one embodiment of the present invention and other epoxy resins, it corresponds to the total amount of the epoxy resin according to one embodiment of the present invention and the other epoxy resins.

[0047] There are no particular restrictions on the curing agent; all commonly known epoxy resin curing agents can be used. Examples include phenolic curing agents, aliphatic amines, polyetheramines, alicyclic amines, aromatic amines and other amine-based curing agents (excluding tertiary amines), tertiary amines, acid anhydride-based curing agents, amide-based curing agents, and imidazoles. Of these, the epoxy resin composition of this embodiment preferably contains a phenolic curing agent, as this allows for excellent heat resistance, stress resistance, moisture resistance, and flame retardancy. Furthermore, from the viewpoint of heat resistance, it is preferable to include an acid anhydride curing agent and an amide curing agent. In addition, the use of imidazoles is also preferable from the viewpoint of ensuring sufficient curing reaction and improving heat resistance. The curing agent may be used alone or in combination of two or more types. When using two or more curing agents in combination, they may be pre-mixed to prepare a mixed curing agent before use, or each component of the curing agent may be added separately and mixed simultaneously when mixing each component of the epoxy resin composition.

[0048] <Phenol-based curing agent> Specific examples of phenolic curing agents include various polyvalent phenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol AD, hydroquinone, resorcinol, methylresorcinol, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, thiodiphenols, phenol novolac resin, cresol novolac resin, phenol aralkyl resin, biphenyl aralkyl resin, naphthol aralkyl resin, terpene phenol resin, dicyclopentadiene phenol resin, bisphenol A novolac resin, trisphenolmethane type resin, naphthol novolac resin, brominated bisphenol A, and brominated phenol novolac resin. Examples include polyhydric phenolic resins obtained by condensation reactions of various phenols with various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, and glyoxal, polyhydric phenolic resins obtained by condensation reactions of xylene resin with phenols, co-condensation resins of heavy oil or pitch with phenols and formaldehydes, various phenolic resins such as phenol-benzaldehyde-xylylenedimethoxide polycondensate, phenol-benzaldehyde-xylylenedihalide polycondensate, phenol-benzaldehyde-4,4'-dimethoxide biphenyl polycondensate, and phenol-benzaldehyde-4,4'-dihalide biphenyl polycondensate. These phenolic curing agents may be used individually or in any combination and mixing ratio of two or more types.

[0049] Among the phenolic curing agents mentioned above, from the viewpoint of heat resistance and curability after curing of the composition, phenol novolac resin (for example, the compound represented by formula (1) below), phenol aralkyl resin (for example, the compound represented by formula (2) below), biphenyl aralkyl resin (for example, the compound represented by formula (3) below), naphthol novolac resin (for example, the compound represented by formula (4) below), naphthol aralkyl resin (for example, the compound represented by formula (5) below), trisphenolmethane type resin (for example, the compound represented by formula (6) below), phenol-benzaldehyde-xylylenedimethoxide polycondensate (for example, the compound represented by formula (7) below), phenol-benzaldehyde-xylylenedihalide polycondensate (for example, the compound represented by formula (7) below), phenol-benzaldehyde-4,4'-dimethoxide biphenyl polycondensate (for example, the compound represented by formula (8) below) Compounds such as phenol-benzaldehyde-4,4'-dihalide biphenyl polycondensate (for example, the compound represented by formula (8) below) are preferred, and phenol novolac resin (for example, the compound represented by formula (1) below), phenol aralkyl resin (for example, the compound represented by formula (2) below), biphenyl aralkyl resin (for example, the compound represented by formula (3) below), phenol-benzaldehyde-xylylenedimethoxide polycondensate (for example, the compound represented by formula (7) below), phenol-benzaldehyde-xylylenedihalide polycondensate (for example, the compound represented by formula (7) below), phenol-benzaldehyde-4,4'-dimethoxide biphenyl polycondensate (for example, the compound represented by formula (8) below), and phenol-benzaldehyde-4,4'-dihalide biphenyl polycondensate (for example, the compound represented by formula (8) below) are particularly preferred.

[0050] [ka] (However, in equations (1) to (6) above, k1 to k6 each represent an integer greater than or equal to 0.) [ka] (However, in equations (7) and (8) above, k7, k8, l1, and l2 each represent an integer greater than or equal to 1.)

[0051] The amount of phenolic curing agent blended is preferably 0.1 to 1000 parts by weight, more preferably 500 parts by weight or less, even more preferably 300 parts by weight or less, and particularly preferably 100 parts by weight or less, based on 100 parts by weight of the total epoxy resin components in the epoxy resin composition.

[0052] <Amine-based curing agent> Examples of amine-based curing agents (excluding tertiary amines) include aliphatic amines, polyetheramines, alicyclic amines, and aromatic amines. Examples of aliphatic amines include ethylenediamine, 1,3-diaminopropane, 1,4-diaminopropane, hexamethylenediamine, 2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, iminobispropylamine, bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-hydroxyethylethylenediamine, and tetra(hydroxyethyl)ethylenediamine. Examples of polyetheramines include triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis(propylamine), polyoxypropylenediamine, and polyoxypropylene triamines. Examples of alicyclic amines include isophoronediamine, mensendiamine, N-aminoethylpiperazine, bis(4-amino-3-methyldicyclohexyl)methane, bis(aminomethyl)cyclohexane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro(5,5)undecane, and norbornenediamine. Examples of aromatic amines include tetrachloro-p-xylenediamine, m-xylenediamine, p-xylenediamine, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, 2,4-diaminoanisole, 2,4-toluenediamine, 2,4-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diamino-1,2-diphenylethane, 2,4-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, m-aminophenol, m-aminobenzylamine, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, triethanolamine, methylbenzylamine, α-(m-aminophenyl)ethylamine, α-(p-aminophenyl)ethylamine, diaminodiethyldimethyldiphenylmethane, and α,α'-bis(4-aminophenyl)-p-diisopropylbenzene. The amine-based curing agents listed above may be used individually or in any combination and mixing ratio of two or more types. The above-mentioned amine-based curing agent is preferably used such that the equivalent ratio of functional groups in the curing agent to epoxy groups in the total epoxy resin components contained in the epoxy resin composition is in the range of 0.8 to 1.5. This range is preferable because it makes it less likely for unreacted epoxy groups or functional groups of the curing agent to remain.

[0053] Examples of tertiary amines include 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol. The tertiary amines listed above may be used individually or in any combination and proportion. The above-mentioned tertiary amine is preferably used in such a way that the equivalent ratio of functional groups in the curing agent to epoxy groups in the total epoxy resin components contained in the epoxy resin composition is in the range of 0.8 to 1.5. This range is preferable because it makes it less likely for unreacted epoxy groups or functional groups of the curing agent to remain.

[0054] <Acid anhydride curing agent> Examples of acid anhydride-based curing agents include acid anhydrides and modified acid anhydrides. Examples of acid anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly(ethyloctadecanediic acid) anhydride, poly(phenylhexadecanedioic acid) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhymic anhydride. Examples include trialkyltetrahydrophthalic anhydride, methylcyclohexenedicarboxylic acid anhydride, methylcyclohexenetetracarboxylic acid anhydride, ethylene glycol bistrimellitate dianhydride, hetic acid anhydride, nadic acid anhydride, methylnadic acid anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic acid anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic acid dianhydride, etc.

[0055] Examples of modified acid anhydrides include those obtained by modifying the aforementioned acid anhydrides with glycol. Examples of glycols that can be used for modification include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol, and polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Furthermore, copolymer polyether glycols of two or more of these glycols and / or polyether glycols can also be used. In modified acid anhydrides, it is preferable to modify them with a glycol content of 0.4 moles or less per mole of acid anhydride. When the amount of modification is below the above upper limit, the viscosity of the epoxy resin composition does not become too high, resulting in good workability, and the curing reaction rate with the epoxy resin also tends to be good. The acid anhydride-based curing agents listed above may be used individually or in any combination and proportion. When using an acid anhydride-based curing agent, it is preferable to use one such agent so that the equivalent ratio of functional groups in the curing agent to epoxy groups in the total epoxy resin components of the epoxy resin composition is in the range of 0.8 to 1.5. This range is preferable because it reduces the likelihood of unreacted epoxy groups or functional groups of the curing agent remaining in the mixture.

[0056] <Amid-based hardening agent> Examples of amide-based curing agents include dicyandiamide and its derivatives, and polyamide resins. The amide-based curing agent may be used alone, or two or more types may be mixed in any combination and ratio. When using an amide-based curing agent, it is preferable to use it in such a way that the amount of amide-based curing agent is 0.1 to 20% by weight relative to the total amount of epoxy resin components and amide-based curing agent in the epoxy resin composition.

[0057] <Imidazoles> Imidazoles include 2-phenylimidazole, 2-ethyl-4(5)-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, and 2,4-diamino-6-[2'-methylimidazolyl- Examples include (1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanurate adduct, 2-phenylimidazole isocyanurate adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and adducts of epoxy resins with the above imidazoles. Although imidazoles generally have catalytic activity and can be classified as curing accelerators, in this invention they are classified as curing agents. The imidazoles listed above may be used individually or as a mixture of two or more in any combination and ratio. When using imidazoles, it is preferable that the amount of imidazoles in the epoxy resin composition be 0.1 to 20% by weight relative to the total amount of all epoxy resin components and imidazoles in the epoxy resin composition.

[0058] <Other hardeners> The epoxy resin composition of this embodiment may contain other curing agents in addition to the curing agent described above. There are no particular limitations on the other curing agents that can be used in the epoxy resin composition of this embodiment; all curing agents that are generally known as epoxy resin curing agents can be used. These other hardening agents may be used individually or in combination of two or more.

[0059] [Other epoxy resins] The epoxy resin composition of this embodiment may further contain other epoxy resins in addition to the epoxy resin of this embodiment. By including other epoxy resins, the heat resistance, stress resistance, moisture resistance, flame retardancy, etc., of the epoxy resin composition of this embodiment can be improved. Other epoxy resins that can be used in the epoxy resin composition of this embodiment include all epoxy resins other than the epoxy resin of this embodiment, but specific examples include bisphenol A type epoxy resin, trisphenolmethane type epoxy resin, anthracene type epoxy resin, phenol-modified xylene resin type epoxy resin, bisphenol cyclododecyl type epoxy resin, bisphenol diisopropylidene resorcinol type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, hydroquinone type epoxy resin, methylhydroquinone type epoxy resin, dibutylhydroquinone type epoxy resin, resorcinol type epoxy resin, methylresorcinol type epoxy resin, biphenol type epoxy resin, tetramethylbiphenol type epoxy resin other than the epoxy resin of this embodiment, tetramethylbisphenol F type epoxy resin, dihydroxydiphenyl ether type epoxy resin, epoxy resin derived from thiodiphenols, dihydroxynaphthalene type epoxy resin, dihydroxyanthracene type epoxy resin, and dihydroxydihydroanthracene type epoxy resin. Examples include resins, dicyclopentadiene-type epoxy resins, epoxy resins derived from dihydroxystilbenes, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, bisphenol A novolac-type epoxy resins, naphthol novolac-type epoxy resins, phenol aralkyl-type epoxy resins, naphthol aralkyl-type epoxy resins, biphenyl aralkyl-type epoxy resins, terpene phenol-type epoxy resins, dicyclopentadiene phenol-type epoxy resins, epoxy resins derived from phenol-hydroxybenzaldehyde condensates, epoxy resins derived from phenol-crotonaldehyde condensates, epoxy resins derived from phenol-glyoxal condensates, epoxy resins derived from co-condensation resins of heavy oils or pitches with phenols and formaldehydes, epoxy resins derived from diaminodiphenylmethane, epoxy resins derived from aminophenols, epoxy resins derived from xylenediamine, epoxy resins derived from methylhexahydrophthalic acid, and epoxy resins derived from dimer acids. These may be used individually, or two or more may be used in any combination and ratio.

[0060] Among these, particularly preferred from the viewpoint of the fluidity of the composition, as well as the heat resistance, moisture resistance, and flame retardancy of the cured product, are bisphenol A type epoxy resin, tetramethylbiphenol type epoxy resin other than the epoxy resin according to one embodiment of the present invention, 4,4'-biphenol type epoxy resin, biphenyl aralkyl type epoxy resin, phenol aralkyl type epoxy resin, dihydroxyanthracene type epoxy resin, dicyclopentadiene type epoxy resin, orthocresol novolac type epoxy resin, and trisphenolmethane type epoxy resin. If the epoxy resin composition of this embodiment contains the above-mentioned other epoxy resins, the content thereof is preferably 0.01 to 60 parts by weight, more preferably 40 parts by weight or less, even more preferably 30 parts by weight or less, particularly preferably 20 parts by weight or less, while more preferably 1 part by weight or more, based on 100 parts by weight of the total epoxy resin components in the composition.

[0061] [Curing accelerator] The epoxy resin composition of this embodiment preferably contains a curing accelerator. By including a curing accelerator, it is possible to shorten the curing time and lower the curing temperature, making it easier to obtain the desired cured product. The curing accelerator is not particularly limited, but specific examples include organophosphines, phosphorus compounds such as phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, and boron halide amine complexes. Phosphorus compounds that can be used as curing accelerators include triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkyl·alkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine Examples include organic phosphines such as fins, dialkylarylphosphines, and alkyldiarylphosphines, or complexes of these organic phosphines with organic borons, and compounds obtained by adding these organic phosphines with compounds such as maleic anhydride, 1,4-benzoquinone, 2,5-tholquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, phenyl-1,4-benzoquinone, phenyl-1,4-benzoquinone, and diazophenylmethane.

[0062] Among the curing accelerators listed above, organophosphines and phosphonium salts are preferred, with organophosphines being the most preferred. Furthermore, the curing accelerator may be used individually from those listed above, or two or more may be mixed in any combination and ratio. The curing accelerator is preferably used in an amount of 0.1 parts by weight or more and 20 parts by weight or less per 100 parts by weight of the total epoxy resin components in the epoxy resin composition. More preferably, it is 0.5 parts by weight or more, even more preferably 1 part by weight or more, while more preferably 15 parts by weight or less, and even more preferably 10 parts by weight or less. When the content of the curing accelerator is above the lower limit, a good curing acceleration effect can be obtained, while when it is below the upper limit, it is preferable because the desired cured physical properties are more easily obtained.

[0063] [Inorganic filler] Inorganic fillers can be added to the epoxy resin composition of this embodiment. Examples of inorganic fillers include fused silica, crystalline silica, glass powder, alumina, calcium carbonate, calcium sulfate, talc, and boron nitride. These may be used individually or in any combination and ratio of two or more. Among these, crushed and / or spherical fused and / or crystalline silica powder fillers are preferred for semiconductor encapsulation applications. By using inorganic fillers, when an epoxy resin composition is used as a semiconductor encapsulant, the thermal expansion coefficient of the semiconductor encapsulant can be brought closer to that of the internal silicon chip or lead frame, and the overall moisture absorption of the semiconductor encapsulant can be reduced, thereby improving solder crack resistance.

[0064] The average particle size of the inorganic filler is typically 0.01 to 50 μm, preferably 1 to 40 μm, and more preferably 2 to 30 μm. An average particle size above the lower limit is preferable because it prevents the melt viscosity from becoming too high and reduces fluidity. An average particle size below the upper limit is preferable because it prevents the filler from clogging the narrow gaps in the mold during molding, improving the material's filling ability. When an inorganic filler is used in the epoxy resin composition of this embodiment, it is preferable that the inorganic filler is blended in an amount of 60 to 95% by weight of the total epoxy resin composition.

[0065] [Release agent] A mold release agent may be added to the epoxy resin composition of this embodiment. Examples of mold release agents include natural waxes such as carnauba wax, synthetic waxes such as polyethylene wax, higher fatty acids such as stearic acid and zinc stearate and their metal salts, and hydrocarbon-based mold release agents such as paraffin. These may be used individually or in any combination and ratio of two or more. When a release agent is added to the epoxy resin composition of this embodiment, the amount of release agent added is preferably 0.1 to 5.0 parts by weight, more preferably 0.5 to 3.0 parts by weight, per 100 parts by weight of the total epoxy resin components in the epoxy resin composition. An amount of release agent within this range is preferable because it allows for good release properties while maintaining the curing characteristics of the epoxy resin composition.

[0066] [Coupling agent] The epoxy resin composition of this embodiment preferably contains a coupling agent. The coupling agent is preferably used in combination with an inorganic filler, and by incorporating the coupling agent, the adhesion between the epoxy resin matrix and the inorganic filler can be improved. Examples of coupling agents include silane coupling agents and titanate coupling agents.

[0067] Examples of silane coupling agents include epoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; aminosilanes such as γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-ureidopropyltriethoxysilane; mercaptosilanes such as 3-mercaptopropyltrimethoxysilane; p-styryltrimethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, vinyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane; and polymeric silanes of epoxy, amino, and vinyl types.

[0068] Examples of titanate coupling agents include isopropyltriisostearoyl titanate, isopropyltri(N-aminoethyl / aminoethyl) titanate, diisopropylbis(dioctyl phosphate) titanate, tetraisopropylbis(dioctyl phosphite) titanate, tetraoctylbis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl) phosphite titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, and bis(dioctyl pyrophosphate) ethylene titanate. These coupling agents may be used individually, or two or more may be mixed in any combination and ratio.

[0069] When a coupling agent is used in the epoxy resin composition of this embodiment, the amount of the coupling agent is preferably 0.1 to 3.0 parts by weight per 100 parts by weight of the total epoxy resin component. When the amount of the coupling agent is above the lower limit, the effect of improving the adhesion between the epoxy resin matrix and the inorganic filler due to the addition of the coupling agent tends to improve, while when the amount of the coupling agent is below the upper limit, the coupling agent is less likely to bleed out from the resulting cured product, which is preferable.

[0070] [Other ingredients] The epoxy resin composition of this embodiment may contain components other than those mentioned above (hereinafter sometimes referred to as "other components"). Examples of other components include flame retardants, plasticizers, reactive diluents, pigments, etc., which may be added as needed. However, the epoxy resin composition of this embodiment does not in any way prevent the addition of components other than those listed above. Flame retardants that can be used in the epoxy resin composition of this embodiment include halogen-based flame retardants such as brominated epoxy resins and brominated phenolic resins, antimony compounds such as antimony trioxide, phosphorus-based flame retardants such as red phosphorus, phosphate esters and phosphines, nitrogen-based flame retardants such as melamine derivatives, and inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide.

[0071] [Cured product] By curing the epoxy resin composition according to one embodiment of the present invention, a cured product with excellent heat resistance can be obtained. That is, another embodiment of the present invention is a cured product obtained by curing the epoxy resin composition according to one embodiment of the present invention. The method for curing the epoxy resin composition is not particularly limited, but a cured product can usually be obtained by a thermosetting reaction caused by heating. During the thermosetting reaction, it is preferable to appropriately select the curing temperature depending on the type of curing agent used. For example, when a phenolic curing agent is used, the curing temperature is usually 100 to 300°C. It is also possible to lower the curing temperature by adding a curing accelerator to these curing agents. The reaction time is preferably 0.01 to 20 hours, and more preferably 0.1 to 10 hours. A reaction time above the lower limit is preferable because it tends to allow the curing reaction to proceed sufficiently. On the other hand, a reaction time below the upper limit is preferable because it is easier to reduce degradation due to heating and energy loss during heating.

[0072] The cured product of this embodiment exhibits excellent heat resistance. Preferably, the glass transition temperature (Tg) of the cured product is 130°C or higher, and the 5% weight loss temperature is 390°C or higher. A higher glass transition temperature and a higher 5% weight loss temperature of the cured product are preferable because they allow the physical properties to be maintained even at high ambient temperatures. Here, the glass transition temperature (Tg) and the 5% weight loss temperature are measured by the method described in the Examples section below.

[0073] [Application] Since the cured product of this embodiment has excellent heat resistance, the phenol resin composition, epoxy resin, epoxy resin composition, and cured product according to each embodiment of the present invention can be effectively used in any application where these physical properties are required. For example, they can be suitably used in the fields of paints such as electrodeposition paints for automobiles, heavy-duty anticorrosive paints for ships and bridges, and paints for coating the inside of beverage cans; in the fields of electrical and electronics such as laminates, semiconductor encapsulants, insulating powder coatings, and coil impregnation; and in the fields of civil engineering, construction, and adhesives such as seismic reinforcement of bridges, concrete reinforcement, flooring materials for buildings, lining for water supply facilities, drainage and permeable pavements, and adhesives for vehicles and aircraft. Among these, they are particularly useful for electrical and electronic component applications such as semiconductor encapsulants and laminates. An epoxy resin composition according to one embodiment of the present invention may be used for the aforementioned application after curing, or it may be cured during the manufacturing process for the aforementioned application. [Examples]

[0074] The present invention will be described more specifically below based on examples, but the present invention is not limited in any way by the following examples. The various manufacturing conditions and evaluation result values ​​in the following examples are meant to represent preferred upper or lower limits in embodiments of the present invention, and the preferred range may be defined by a combination of the aforementioned upper or lower limits and the values ​​of the following examples or the values ​​of different examples.

[0075] [Measurement and Evaluation Methods] <Composition of phenol mixture> (1) Analysis of 2,6-xylenol (XNL) and 4-(2,6-dimethylphenoxy)-2,6-dimethylphenol (ED): Quantitative analysis was performed by gas chromatography. A phenylmethyl silicone capillary column with a degree of crosslinking of 5% (J&W "CBP-5") was used as the column, a flame ionization detector (FID) was used as the detector, and diphenyl was used as the internal standard. The sample was prepared by dissolving 2 g of the sample in 25 mL of acetone. (2) Analysis of tetramethyldiphenoquinone (DPQ): Quantitative analysis was performed by spectrophotometric method. The cell length was 10 mm, the measurement wavelength was 420 nm, and the sample was prepared by dissolving 0.5 g of the sample in 100 mL of chloroform. (3) Analysis of polyphenylene ether (PPE) and 3,3',5,5'-tetramethyl-4,4'-biphenol (TMBPL): Quantitative analysis was performed by liquid chromatography. A SHODEX KF-801 molecular sieve column (exclusion limit molecular weight: approximately 1500) manufactured by Showa Denko Corporation was used, tetrahydrofuran was used as the carrier (mobile phase), a UV detector (268 nm) was used as the detector, and benzene was used as the internal standard. The sample to be measured was prepared by dissolving 50 mg of the sample in 5 mL of tetrahydrofuran.

[0076] [Production of phenol mixtures] [Example 1] In a 30L stainless steel reactor with baffles, 4kg of 2,6-xylenol (XNL), 400g of borax, 13g of sodium lauryl sulfate, 12kg of water, and 0.2g of cupric acetate were charged and heated while stirring. When the contents temperature reached 70°C, 0.26kg of oxygen was introduced. Stirring continued to maintain the reaction temperature at 70°C, and after 12 hours, the oxygen introduction was stopped and the reaction system was purged with nitrogen. Then, 25% sulfuric acid was added to adjust the pH of the resulting slurry to 7.5, and the temperature was gradually increased and distillation was performed to remove water and unreacted 2,6-xylenol. After that, the temperature in the reactor was cooled to 70°C, 25% sulfuric acid was added to adjust the pH of the reaction solution to 6.5, and then 1.75kg of water and 6.05kg of isopropyl alcohol were added, and the mixture was stirred for 30 minutes while maintaining the temperature at 60°C. The mixture was then maintained at 60°C, and the resulting slurry was treated with a centrifuge to separate the solid and liquid components. The solid in the centrifuge was then rinsed with 5 kg of 60°C hot water. The resulting solid was dried using a vacuum dryer to obtain a phenol mixture.

[0077] [Example 2] In a 30L stainless steel reactor with baffles, 4kg of 2,6-xylenol (XNL), 400g of borax, 13g of sodium lauryl sulfate, 12kg of water, and 0.2g of cupric acetate were charged and heated while stirring. When the contents temperature reached 70°C, 0.27kg of oxygen was introduced. Stirring continued to maintain the reaction temperature at 70°C, and after 12 hours, the oxygen introduction was stopped and the reaction system was purged with nitrogen. Then, 25% sulfuric acid was added to adjust the pH of the resulting slurry to 7.8, and the temperature was gradually increased and distillation was performed to remove water and unreacted 2,6-xylenol. After that, the temperature in the reactor was cooled to 70°C, 25% sulfuric acid was added to adjust the pH of the reaction solution to 6.5, and then 1.75kg of water and 6.05kg of isopropyl alcohol were added, and the mixture was stirred for 30 minutes while maintaining the temperature at 60°C. The mixture was then maintained at 60°C, and the resulting slurry was treated with a centrifuge to separate the solid and liquid components. The solid in the centrifuge was then rinsed with 5 kg of 60°C hot water. The resulting solid was dried using a vacuum dryer to obtain a phenol mixture.

[0078] [Example 3] In a 30L stainless steel reactor with baffles, 4kg of 2,6-xylenol (XNL), 400g of borax, 13g of sodium lauryl sulfate, 12kg of water, and 0.2g of cupric acetate were charged and heated while stirring. When the contents temperature reached 70°C, 0.31kg of oxygen was introduced. Stirring continued to maintain the reaction temperature at 70°C, and after 12 hours, the oxygen introduction was stopped and the reaction system was purged with nitrogen. Then, 25% sulfuric acid was added to adjust the pH of the resulting slurry to 8.1, and the temperature was gradually increased and distillation was performed to distill off water and unreacted 2,6-xylenol. After that, the temperature in the reactor was cooled to 70°C, 25% sulfuric acid was added to adjust the pH of the reaction solution to 6.5, and then 1.75kg of water and 6.05kg of isopropyl alcohol were added, and the mixture was stirred for 30 minutes while maintaining the temperature at 60°C. The mixture was then maintained at 60°C, and the resulting slurry was treated with a centrifuge to separate the solid and liquid components. The solid in the centrifuge was then rinsed with 5 kg of 60°C hot water. The resulting solid was dried using a vacuum dryer to obtain a phenol mixture.

[0079] [Example 4] In a 30L stainless steel reactor with baffles, 4kg of 2,6-xylenol (XNL), 400g of borax, 13g of sodium lauryl sulfate, 12kg of water, and 0.2g of cupric acetate were charged and heated while stirring. When the contents temperature reached 70°C, 0.40kg of oxygen was introduced. Stirring continued to maintain the reaction temperature at 70°C, and after 12 hours, the oxygen introduction was stopped and the reaction system was purged with nitrogen. Then, 25% sulfuric acid was added to adjust the pH of the resulting slurry to 8.5, and the temperature was gradually increased and distillation was performed to remove water and unreacted 2,6-xylenol. After that, the temperature in the reactor was cooled to 70°C, 25% sulfuric acid was added to adjust the pH of the reaction solution to 6.5, and then 1.75kg of water and 6.05kg of isopropyl alcohol were added, and the mixture was stirred for 30 minutes while maintaining the temperature at 60°C. The mixture was then maintained at 60°C, and the resulting slurry was treated with a centrifuge to separate the solid and liquid components. The solid in the centrifuge was then rinsed with 5 kg of 60°C hot water. The resulting solid was dried using a vacuum dryer to obtain a phenol mixture.

[0080] [Example 5] In a 30L stainless steel reactor with baffles, 4kg of 2,6-xylenol (XNL), 400g of borax, 13g of sodium lauryl sulfate, 12kg of water, and 0.2g of cupric acetate were charged and heated while stirring. When the contents temperature reached 70°C, 0.47kg of oxygen was introduced. Stirring continued to maintain the reaction temperature at 70°C, and after 12 hours, the oxygen introduction was stopped and the reaction system was purged with nitrogen. Then, 25% sulfuric acid was added to adjust the pH of the resulting slurry to 9.0, and the temperature was gradually increased and distillation was performed to remove water and unreacted 2,6-xylenol. After that, the temperature in the reactor was cooled to 70°C, and 25% sulfuric acid was added to adjust the pH of the reaction solution to 6.5, and then 1.75kg of water and 6.05kg of isopropyl alcohol were added, and the mixture was stirred for 30 minutes while maintaining the temperature at 60°C. The mixture was then maintained at 60°C, and the resulting slurry was treated with a centrifuge to separate the solid and liquid components. The solid in the centrifuge was then rinsed with 5 kg of 60°C hot water. The resulting solid was dried using a vacuum dryer to obtain a phenol mixture.

[0081] [Comparative Example 1] A phenol mixture was obtained in the same manner as in Example 1 described in Japanese Patent Publication No. 2003-327554. In a 30L stainless steel reactor with baffles, 4kg of 2,6-xylenol (XNL), 400g of borax, 13g of sodium lauryl sulfate, and 12kg of water were charged and heated while stirring. When the temperature of the contents reached 70°C, 0.2g of cupric acetate was added and 0.21kg of oxygen was introduced. Stirring continued to maintain the reaction temperature at 70°C, and after 12 hours, the introduction of oxygen was stopped and the reaction system was purged with nitrogen. Then, 25% sulfuric acid was added to adjust the pH of the resulting slurry to 6.5, and the temperature was gradually increased and distillation was performed to distill off water and unreacted 2,6-xylenol. After that, the temperature in the reactor was cooled to 70°C, 25% sulfuric acid was added to adjust the pH of the resulting slurry to 3.8, and then 1.75kg of water and 6.05kg of isopropyl alcohol were added, and the mixture was stirred for 30 minutes while maintaining the temperature at 60°C. The obtained slurry was separated into solid and liquid components using a centrifuge, and the solid in the centrifuge was rinsed with 5 kg of 60°C hot water. The resulting solid was dried using a vacuum dryer to obtain a phenol mixture.

[0082] [Comparative Example 2] A phenol mixture was obtained in the same manner as in Comparative Example 1 described in Japanese Patent Publication No. 2004-002830. In a 30L stainless steel reactor with baffles, 4kg of 2,6-xylenol (XNL), 400g of borax, 13g of sodium lauryl sulfate, and 12kg of water were charged and heated while stirring. When the temperature of the contents reached 70°C, 0.2g of cupric acetate was added and 0.21kg of oxygen was introduced. Stirring continued to maintain the reaction temperature at 70°C, and after 12 hours, the introduction of oxygen was stopped and the reaction system was purged with nitrogen. Then, 25% sulfuric acid was added to adjust the pH of the resulting slurry to 6.5, and the temperature was gradually increased and distillation was performed to distill off water and unreacted 2,6-xylenol. After that, the temperature in the reactor was cooled to 70°C, 25% sulfuric acid was added to adjust the pH of the resulting slurry to 3.8, and then 1.75kg of water and 6.05kg of isopropyl alcohol were added, and the mixture was stirred for 30 minutes while adjusting the temperature to 60°C. The mixture was then maintained at 60°C, and the resulting slurry was treated with a centrifuge to separate the solid and liquid components. The solid in the centrifuge was rinsed with 5 kg of 60°C hot water. The resulting solid was dried in a vacuum dryer to obtain phenol resin. 1 kg of the obtained phenol resin was mixed with 4.6 kg of isopropyl alcohol and 1.5 kg of water and placed in a stirring tank. The mixture was heated under pressure to 110°C and stirred for 2 hours. After cooling to 30°C, the mixture was separated into solid and liquid components using a centrifuge. The resulting solid was then purified again in the same manner by adding 4.1 kg of isopropyl alcohol and 1.4 kg of water to obtain a phenol mixture.

[0083] [Comparative Example 3] A phenol mixture was obtained in the same manner as in Example 1 described in Japanese Patent Publication No. 61-268641. In a 10L stainless steel reactor with baffles, 0.915 kg of 2,6-xylenol (XNL), 100 g of borax, 3 g of sodium lauryl sulfate, and 2.75 kg of water were charged and heated while stirring. When the temperature of the contents reached 65°C, 0.06 g of cupric acetate was added and 0.048 kg of oxygen was introduced. Stirring continued to maintain the reaction temperature at 70°C, and after 8 hours, the oxygen introduction was stopped and the reaction system was purged with nitrogen. Then, while maintaining the temperature in the reactor at 70°C, 25% sulfuric acid was added to adjust the pH of the reaction solution to 6.5, and then 0.44 kg of water and 1.5 kg of isopropyl alcohol were added and stirred for 30 minutes while maintaining the temperature at 60°C. After that, the temperature was maintained at 60°C, and the resulting slurry was treated with a centrifuge to separate the solid and liquid, and the solid in the centrifuge was rinsed with 1 kg of 60°C warm water. The resulting solid was dried in a vacuum dryer to obtain a phenol mixture.

[0084] [Comparative Example 4] A phenol mixture was obtained in the same manner as in Example 2 described in Japanese Patent Publication No. 61-268641. In a 10L stainless steel reactor with baffles, 0.915 kg of 2,6-xylenol (XNL), 60 g of sodium hydroxide, 3 g of sodium lauryl sulfate, and 2.75 kg of water were charged and heated while stirring. When the temperature of the contents reached 65°C, 0.06 g of cupric acetate was added and 0.048 kg of oxygen was introduced. Stirring continued to maintain the reaction temperature at 70°C, and after 8 hours, the introduction of oxygen was stopped and the reaction system was purged with nitrogen. Then, while maintaining the temperature in the reactor at 70°C, 25% sulfuric acid was added to adjust the pH of the reaction solution to 6.5, and then 0.44 kg of water and 1.5 kg of isopropyl alcohol were added and stirred for 30 minutes while adjusting the temperature to 60°C. After that, the temperature was maintained at 60°C, and the resulting slurry was treated with a centrifuge to separate the solid and liquid, and the solid in the centrifuge was rinsed with 1 kg of 60°C warm water. The resulting solid was dried in a vacuum dryer to obtain a phenol mixture.

[0085] [Comparative Example 5] In a 30L stainless steel reactor with baffles, 4kg of 2,6-xylenol (XNL), 400g of borax, 13g of sodium lauryl sulfate, 12kg of water, and 0.2g of cupric acetate were charged and heated while stirring. When the contents temperature reached 70°C, 0.52kg of oxygen was introduced. Stirring continued to maintain the reaction temperature at 70°C, and after 12 hours, the oxygen introduction was stopped and the reaction system was purged with nitrogen. Then, 25% sulfuric acid was added to adjust the pH of the resulting slurry to 9.3, and the temperature was gradually increased and distillation was performed to distill off water and unreacted 2,6-xylenol. After that, the temperature in the reactor was cooled to 70°C, 25% sulfuric acid was added to adjust the pH of the reaction solution to 6.5, and then 1.75kg of water and 6.05kg of isopropyl alcohol were added, and the mixture was stirred for 30 minutes while maintaining the temperature at 60°C. The mixture was then maintained at 60°C, and the resulting slurry was treated with a centrifuge to separate the solid and liquid components. The solid in the centrifuge was then rinsed with 5 kg of 60°C hot water. The resulting solid was dried using a vacuum dryer to obtain a phenol mixture.

[0086] Tables 1 and 2 show the composition of the phenol mixture (proportions (by weight) of PPE, TMBPL, ED, DPQ, and XNL).

[0087] [Table 1]

[0088] [Table 2]

[0089] [Manufacturing of epoxy resin] [Example 6] In a 2L three-necked flask equipped with a thermometer, stirrer, and condenser, 121g of the phenol mixture obtained in Example 1, 555g of epichlorohydrin, and 200g of isopropyl alcohol were charged. After raising the temperature to 40°C, 91g of 48.5% aqueous sodium hydroxide solution was added dropwise over 1 hour while stirring. During this time, the temperature was gradually increased until the temperature in the system reached 65°C at the end of the dropwise addition. The reaction was then carried out at 65°C for 30 minutes. After the reaction was complete, the mixture was washed with water to remove by-product salts and excess sodium hydroxide. Next, excess epichlorohydrin and isopropyl alcohol were removed from the product under reduced pressure to obtain epoxy resin. The obtained epoxy resin was dissolved in 250g of methyl isobutyl ketone, 2g of 48.5% aqueous sodium hydroxide solution was added, and the mixture was reacted at 65°C for 1 hour. After the reaction was complete, sodium dihydrogen phosphate dihydrate was added to neutralize the sodium hydroxide and remove the by-product salts. Next, after filtering off the insoluble material, methyl isobutyl ketone was completely removed under reduced pressure to obtain the target epoxy resin. The epoxy equivalents are shown in Table 3.

[0090] [Example 7] The synthesis was carried out in the same manner as in Example 6, except that the phenol mixture obtained in Example 2 was used. The epoxy equivalents are shown in Table 3.

[0091] [Example 8] The synthesis was carried out in the same manner as in Example 6, except that the phenol mixture obtained in Example 3 was used. The epoxy equivalents are shown in Table 3.

[0092] [Example 9] The synthesis was carried out in the same manner as in Example 6, except that the phenol mixture obtained in Example 4 was used. The epoxy equivalents are shown in Table 3.

[0093] [Example 10] The synthesis was carried out in the same manner as in Example 6, except that the phenol mixture obtained in Example 5 was used. The epoxy equivalents are shown in Table 3.

[0094] [Comparative Example 6] The synthesis was carried out in the same manner as in Example 6, except that the phenol mixture obtained in Comparative Example 1 was used. The epoxy equivalents are shown in Table 3.

[0095] [Comparative Example 7] The synthesis was carried out in the same manner as in Example 6, except that the phenol mixture obtained in Comparative Example 2 was used. The epoxy equivalents are shown in Table 3.

[0096] [Comparative Example 8] The synthesis was carried out in the same manner as in Example 6, except that the phenol mixture obtained in Comparative Example 3 was used. The epoxy equivalents are shown in Table 3.

[0097] [Comparative Example 9] The synthesis was carried out in the same manner as in Example 6, except that the phenol mixture obtained in Comparative Example 4 was used. The epoxy equivalents are shown in Table 3.

[0098] [Comparative Example 10] The synthesis was carried out in the same manner as in Example 6, except that the phenol mixture obtained in Comparative Example 5 was used. The epoxy equivalents are shown in Table 3.

[0099] [Table 3]

[0100] [Manufacture of epoxy resin compositions and cured products: Examples 11-15, Comparative Examples 11-15] Epoxy resin compositions having the compositions shown in Tables 4 and 5 were prepared using the epoxy resins obtained in Examples 6-10 and Comparative Examples 6-10. A phenolic aralkyl resin represented by formula (2) (MEHC7800SS, manufactured by Meiwa Chemical Industries, Ltd., hydroxyl group equivalent 174 g / eq) was used as the phenolic curing agent, and triphenylphosphine (Hokko TPP, manufactured by Hokko Chemical Industry Co., Ltd.) was used as the curing accelerator. These were heated in an oven at 120°C for 2 hours and at 175°C for 6 hours to produce cured products. The glass transition temperature (Tg) and 5% weight loss temperature of the cured products were measured. A Tg of 130°C or higher and a 5% weight loss temperature of 390°C or higher was classified as heat-resistant (○), and a Tg of 130°C or lower or a 5% weight loss temperature of 390°C or lower was classified as heat-resistant (×). In the table, "parts" refers to "parts by weight".

[0101] [Measurement of glass transition temperature (Tg)] Test specimens were obtained by cutting the hardened material into pieces measuring 5 cm in length, 1 cm in width, and 4 mm in thickness. A thermomechanical analyzer (DMS: EXSTAR6100, Seiko Instruments Corporation) was used to measure the temperature increase from 30°C to 250°C at 5°C / min using a three-point bending mode at 1 Hz, and the temperature at the peak of the loss tangent (tanδ) was defined as Tg.

[0102] [Method for measuring 5% weight loss temperature] 100 mg of the cured material was scraped off, and 10 mg was weighed out to be used as a sample. Thermal analysis was performed on this sample using a thermal analyzer (TG / DTA: EXSTAR7200, Seiko Instruments Corporation) (heating rate: 5°C / min, measurement temperature range: 30°C to 350°C, air: flow rate 200 mL / min). The temperature at which the weight of the cured material decreased by 5% was measured and defined as the 5% weight loss temperature.

[0103] [Table 4]

[0104] [Table 5]

[0105] [Evaluation of results] Tables 4 and 5 show that the cured products of Examples 11 to 15 have superior heat resistance compared to the cured products of Comparative Examples 11 to 15.

Claims

1. A phenol mixture having 3,3',5,5'-tetramethyl-4,4'-biphenol as the main component, containing more than 0.3% by weight and less than 10.0% by weight of polyphenylene ether, and containing 1.3% to 4.0% by weight of tetramethyldiphenoquinone.

2. An epoxy resin obtained by reacting the phenol mixture described in claim 1 with an epihalohydrin.

3. An epoxy resin composition comprising 0.01 to 1000 parts by weight of a curing agent per 100 parts by weight of the epoxy resin according to claim 2.

4. The epoxy resin composition according to claim 3, wherein the curing agent is at least one selected from the group consisting of phenolic curing agents, amine curing agents, tertiary amines, acid anhydride curing agents, amide curing agents, and imidazoles.

5. The epoxy resin composition according to claim 3, further comprising an epoxy resin different from the epoxy resin in the epoxy resin composition.

6. A cured product obtained by curing the epoxy resin composition according to any one of claims 3 to 5.

7. An electrical or electronic component obtained by curing an epoxy resin composition according to any one of claims 3 to 5.

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