Polyhydroxy resin, epoxy resin, and composition and cured product thereof
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- NIPPON STEEL CHEM & MATERIAL CO LTD
- Filing Date
- 2026-01-16
- Publication Date
- 2026-07-30
Smart Images
Figure JP2026001211_30072026_PF_FP_ABST
Abstract
Description
Polyvalent hydroxy resins, epoxy resins, and their compositions and cured products
[0001] The present invention relates to polyvalent hydroxy resins, epoxy resins, epoxy resin compositions, and epoxy resin cured products thereof, and more particularly to epoxy resin compositions useful as insulating materials for electrical and electronic components such as semiconductor encapsulants, laminates, and heat dissipation substrates.
[0002] Printed circuit boards, encapsulants, and casting materials used in communication equipment are being actively researched to improve signal transmission speed in line with the increasing communication speed and volume. In addition, there is a demand for curable resins that can be multilayered in printed circuit board applications. Electronic computing components that process such large amounts of data generate a lot of heat, and heat accumulation can cause malfunctions such as a decrease in the processing speed of the electronic computing components. Therefore, various techniques are known for cooling printed circuit boards appropriately using heat sinks, such as incorporating heat transfer materials such as copper coins and copper inlays (Patent Document 1), or making the shape of the filler compounded into the board special (Patent Document 2). However, these methods are undesirable because they lead to increased weight and larger equipment.
[0003] Furthermore, in encapsulant compositions, methods have been employed to remove heat from electronic computing components by examining the types and amounts of various fillers to increase thermal conductivity. For example, attempts have been made to include inorganic fillers with high thermal conductivity, such as crystalline silica, silicon nitride, aluminum nitride, and spherical alumina powder (Patent Documents 3 and 4). However, increasing the content of inorganic fillers leads to an increase in viscosity during molding and a decrease in fluidity, resulting in impaired moldability. Therefore, simply increasing the content of inorganic fillers has its limitations.
[0004] Given the above background, methods to improve the thermal conductivity of the composition by increasing the thermal conductivity of the matrix resin itself have also been investigated. For example, liquid crystalline epoxy resins having rigid mesogenic groups and epoxy resin compositions using the same have been proposed (Patent Documents 5 and 6). However, aromatic diamine compounds are used as curing agents in these epoxy resin compositions, which limits the ability to increase the filling density of the inorganic filler and also presents problems in terms of electrical insulation. Furthermore, when aromatic diamine compounds are used, although the liquid crystalline properties of the cured product can be confirmed, the degree of crystallinity of the cured product is low, and it is not sufficient in terms of high thermal conductivity, low thermal expansion, and low hygroscopicity. Moreover, in order to exhibit liquid crystalline properties, it is necessary to orient the molecules by applying a strong magnetic field, which presents significant equipment constraints for widespread industrial use.
[0005] Patent Document 7 proposes reducing crystallinity by removing the crystalline component of an epoxy resin having a biphenol-biphenylaralkyl structure, but this method has problems with practicality due to insufficient solvent solubility. Furthermore, when mixing with another epoxy resin to improve moldability and solvent solubility, the melting point of the resin is lowered, making uniform mixing easier, but it becomes difficult to maintain the physical properties of the cured product, such as heat resistance, thermal decomposition stability, mechanical strength, and thermal conductivity. Patent Document 8 proposes a resin composition using a combination of biphenol aralkyl type epoxy resin and bisphenol methane type epoxy resin, but due to its strong crystallinity, melt kneading is difficult, and its solvent solubility is insufficient for practical use in laminate applications.
[0006] On the other hand, in the design of thermosetting plastics, there is a growing trend towards developing materials that actively utilize biomass raw materials from the perspective of conserving petroleum resources and reducing carbon dioxide emissions. For example, it is known that to form thermosetting plastics, a curing reaction is carried out using plant-derived raw materials as curing agents to obtain cured products. Many of these biomass materials are alcohols derived from sugars or aliphatic compounds modified from vegetable oils. As a specific example of using aliphatic compounds modified from vegetable oils, a method is known in which cured products are produced using epoxidized vegetable oil in which double bonds have been modified to epoxy groups (Patent Document 9). Alternatively, it is known that cured products are obtained by using biomass materials having a benzene ring, such as lignin, as a curing agent (Patent Document 10). Lignin is a woody component and a high-molecular-weight phenolic compound, and it is known that high heat resistance can be expected when cured products are produced by carrying out a curing reaction using such lignin.
[0007] However, the cured product formed by the method described in Patent Document 9 had a very low glass transition temperature, and in some cases, the glass transition temperature could drop to around 5°C. Therefore, it could not be used as an electronic material component or a building structural component that requires high heat resistance, severely limiting its applications. Furthermore, the cured product obtained from biomass material having a benzene ring, as described in Patent Document 10, had a large molecular weight and strong intermolecular hydrogen bonds, so it had no melting point and was also difficult to dissolve in solvents. Therefore, although it was possible to obtain a thermosetting plastic with high heat resistance, its moldability was impaired, making it difficult to use as a raw material for thermosetting plastics.
[0008] Japanese Patent Publication No. 2009-170493, International Publication No. 2013 / 100172, Japanese Patent Publication No. 11-147936, Japanese Patent Publication No. 2002-309067, Japanese Patent Publication No. 11-323162, Japanese Patent Publication No. 9-118673, Japanese Patent Publication No. 2017-95524, Japanese Patent Publication No. 2015-160893, Japanese Patent Publication No. 2006-241331, Japanese Patent Publication No. 2009-263549
[0009] The object of the present invention is to provide an epoxy resin composition useful for sealing electrical and electronic components, circuit board materials, etc., which exhibits good melt-moldability below 100°C, excellent solvent solubility, and a cured product with excellent heat resistance, thermal decomposition stability, thermal conductivity, and flame retardancy, and to provide a cured product thereof. Another object is to provide an epoxy resin used in this epoxy resin composition and a polyvalent hydroxy resin suitable as an intermediate for this epoxy resin. Furthermore, the invention aims to provide a carbon-neutral epoxy resin and a polyvalent hydroxy resin.
[0010] The inventors have conducted thorough research and found that epoxy resins having a specific structure are expected to solve the above problems, and that their cured products exhibit effects on heat resistance, thermal decomposition stability, thermal conductivity, and flame retardancy.
[0011] In other words, the present invention relates to an epoxy resin represented by the following general formula (1). In formula (1), R １ R independently represents a hydrogen atom, a fluorine atom, an alkoxy group, or a monovalent hydrocarbon group having 1 to 6 carbon atoms. ２ ~R ４ Each of these independently represents a hydrogen atom, a fluorine atom, an alkoxy group, a monovalent C1-C6 hydrocarbon group, or a glycidyl ether group. n represents a number from 1 to 5.
[0012] The content of n=1 in the above epoxy resin is 50% or more, as measured by gel permeation chromatography (GPC) in area percentage.
[0013] Furthermore, the present invention relates to a polyvalent hydroxy resin represented by the following general formula (2). In formula (2), R １ R independently represents a hydrogen atom, a fluorine atom, an alkoxy group, or a monovalent hydrocarbon group having 1 to 6 carbon atoms. ２ ~R ４ Each of these independently represents a hydrogen atom, a fluorine atom, an alkoxy group, and a monovalent hydrocarbon group or hydroxyl group having 1 to 6 carbon atoms. n represents a number from 1 to 5. The content of n=1 in the above polyvalent hydroxy resin is 50% or more in area percent as measured by GPC.
[0014] The epoxy resin described above is obtained by reacting a phenolic compound, an aromatic aldehyde, and epichlorohydrin, and it is preferable that either or both of the phenolic compound and the aromatic aldehyde are derived from plants.
[0015] The polyhydroxy resin described above is obtained by reacting a phenolic compound and an aromatic aldehyde, and it is preferable that either or both of the phenolic compound and the aromatic aldehyde are derived from plants.
[0016] Further, the present invention is an epoxy resin composition characterized by containing the above epoxy resin or the above polyhydroxy resin as an essential component. Furthermore, the present invention is a resin cured product characterized by curing this resin composition.
[0017] The polyhydroxy resin and epoxy resin of the present invention have good melt kneadability at 100 °C or lower and excellent solvent solubility, so they are suitable for epoxy resin compositions and their cured products used in applications such as lamination, molding, casting, and adhesion. And since this cured product is also excellent in heat resistance, thermal decomposition stability, and thermal conductivity, it is suitable for encapsulation of electric and electronic components, circuit board materials, etc. Also, it can be obtained from plant-derived raw materials and is suitable as a material for reducing petroleum resources and suppressing carbon dioxide emissions.
[0018] It is a GPC chart of the polyfunctional hydroxy resin a obtained in Example 1. It is a GPC chart of the epoxy resin A obtained in Example 4.
[0019] Hereinafter, the present invention will be described in detail.
[0020] The present invention is an epoxy resin represented by the following general formula (1). R １ independently represents a hydrogen atom, a fluorine atom, an alkoxy group, or a monovalent hydrocarbon group having 1 to 6 carbon atoms. R ２ ~ R ４ each independently represents a hydrogen atom, a fluorine atom, an alkoxy group, a monovalent hydrocarbon group having 1 to 6 carbon atoms, or a glycidyl ether group. R １ ~ R ４From the viewpoint of solvent solubility, alkyl groups and alkoxy groups are preferred, and from the viewpoint of heat resistance and high thermal conductivity, aromatic groups are preferred. Also, R ２ ~R ４ If either of the groups is a glycidyl ether group, the crosslinking density of the cured product improves, making it suitable for heat resistance and high thermal conductivity. From the viewpoint of dielectric properties, fluorine atoms are preferred. Alkyl alkyl groups with more than 6 carbon atoms make it difficult to suppress molecular motion, and a decrease in mismatch is a concern. Also, bulky structures with high steric hindrance raise concerns about solvent solubility due to increased crystallinity. R １ A more preferred structure is a hydrogen atom, a methyl group, an ethyl group, a methoxy group, or an ethoxy group, R ２ ~R ４ A more preferred structure is a hydrogen atom, methyl group, ethyl group, methoxy group, ethoxy group, or glycidyl ether group. The epoxy resin is R １ ~R ４ It may also be a mixture of different structures.
[0021] The number-average molecular weight (Mn) of the epoxy resin of the present invention is preferably 1500 or less, and more preferably 1000 or less. The lower limit of Mn is not limited, but is preferably 100 or more, and more preferably 150 or more. n is the repeating number, representing a number from 1 to 5. Preferably, it is a mixture of components with different n values. The n value, as a number average, is from 1 to 5, and preferably from 1 to 3. Since the n=0 component exhibits strong crystallinity and there are concerns about reduced solvent solubility, the n=0 component is preferably 20 area% or less in GPC area%, and the thermal conductivity tends to decrease when the content of n=3 or higher is 50 area% or more. In particular, the thermal conductivity tends to increase when the content of n=1 component is 50 area% or more, and more preferably 70 area% or more. １ When the atom is something other than a hydrogen atom, the increase in molecular weight can be suppressed, and the n=1 compound can be selectively obtained. Furthermore, while the epoxy resin of the present invention excludes the n=0 compound alone, it may also be a mixture with the n=0 compound.
[0022] The epoxy resin of the present invention preferably has an epoxy equivalent in the range of 130 to 300 g / eq., more preferably in the range of 140 to 250 g / eq. When it is smaller than this range, reaction control becomes difficult because the reaction proceeds rapidly. When it is larger than this range, there is a concern that the reactivity decreases and it becomes difficult to obtain a uniform cured product. The preferred range of the softening point is 50 to 100 °C. When it is smaller than this range, there is a concern that it is likely to block and it becomes difficult to store at room temperature. When it is larger than this range, there is a concern that it will not melt during melt kneading and become non-uniform.
[0023] The epoxy resin of the present invention can preferably be obtained by reacting a polyhydroxy resin represented by the formula (2) with epichlorohydrin. In the formula (2), R １ independently represents a hydrogen atom, a fluorine atom, an alkoxy group or a monovalent hydrocarbon group having 1 to 6 carbon atoms. R ２ to R ４ each independently represents a hydrogen atom, a fluorine atom, an alkoxy group, a monovalent hydrocarbon group having 1 to 6 carbon atoms or a hydroxy group.
[0024] The polyhydroxy resin of the formula (2) preferably has a hydroxyl equivalent of 40 to 180 g / eq., more preferably 60 to 140 g / eq. The number average molecular weight (Mn) is preferably 1200 or less, more preferably 800 or less. The lower limit of Mn is not limited, but it is preferably 100 or more, more preferably 150 or more. Similar to the epoxy resin represented by the formula (1), n is the repetition number and represents a number from 1 to 5. Preferably, it is a mixture of components having different n values. The n value is, on a number average basis, from 1 to 5, preferably from 1 to 3. Since the n = 0 form has strong crystallinity and there is a concern about a decrease in solvent solubility, in terms of GPC area%, the n = 0 form is preferably 20 area% or less. When the content of n = 3 or more becomes 50 area% or more, the thermal conductivity tends to decrease. In particular, when the content of the n = 1 form becomes 50 area% or more, the thermal conductivity tends to increase, and 70 area% or more is more preferable.
[0025] The polyvalent hydroxy resin of formula (2) can be produced by general methods, and the production method is not limited as long as it has a predetermined structure, but for example, it can be obtained by polycondensation of a divalent phenol compound such as hydroquinone with an aromatic aldehyde. The divalent phenol compound is not limited, and known ones can be used, but as in the case of n=0 in formula (2) above, R as a substituent. １ Those having a group are preferably used. Here, R １ As mentioned above, the groups are independently a hydrogen atom, a fluorine atom, an alkoxy group, or a monovalent hydrocarbon group having 1 to 6 carbon atoms. Among such divalent phenol compounds, for example, 2-methoxyhydroquinone can be obtained from plant-derived 4-hydroxy-3-methoxybenzaldehyde (also known as vanillin), making it suitable as a material for conserving petroleum resources and suppressing carbon dioxide emissions.
[0026] Examples of aromatic aldehydes include benzaldehyde, 4-methylbenzaldehyde, 4-ethylbenzaldehyde, 4-fluorobenzaldehyde, 4-methoxybenzaldehyde, 4-phenylbenzaldehyde, 3-methylbenzaldehyde, 3-ethylbenzaldehyde, 3-fluorobenzaldehyde, 3-methoxybenzaldehyde, 2-methylbenzaldehyde, 2-ethylbenzaldehyde, 2-fluorobenzaldehyde, 2-methoxybenzaldehyde, 5-fluoro-2-methylbenzaldehyde, 4-fluoro-3-methylbenzaldehyde, 4-fluoro-2-methylbenzaldehyde, 3-fluoro-5-methylbenzaldehyde, 3-fluoro-4-methylbenzaldehyde, and 3 Examples include fluoro-2-methylbenzaldehyde, 2-fluoro-6-methylbenzaldehyde, 2-fluoro-5-methylbenzaldehyde, 2-fluoro-4-methylbenzaldehyde, 2-fluoro-3-methylbenzaldehyde, 2,6-difluorobenzaldehyde, 2,5-difluorobenzaldehyde, 2,4-difluorobenzaldehyde, 2,3-difluorobenzaldehyde, 3,5-difluorobenzaldehyde, 3,4-difluorobenzaldehyde, 2,6-dimethylbenzaldehyde, 2,5-dimethylbenzaldehyde, 2,4-dimethylbenzaldehyde, 2,3-dimethylbenzaldehyde, 3,5-dimethylbenzaldehyde, and 3,4-dimethylbenzaldehyde. Examples of plant-derived aromatic aldehydes include 4-hydroxy-3-methoxybenzaldehyde (also known as vanillin), 3,5-dimethoxy-4-hydroxybenzaldehyde (also known as syringaldehyde), and 4-methoxybenzaldehyde (also known as anisaldehyde). From the viewpoint of solvent solubility and thermal conductivity, benzaldehyde, 4-methylbenzaldehyde, 4-ethylbenzaldehyde, 4-fluorobenzaldehyde, 4-methoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, and 3,5-dimethoxy-4-hydroxybenzaldehyde are preferred. These can also be used in combination.
[0027] The polycondensation of a divalent phenol compound and an aromatic aldehyde may use an acid catalyst. For example, acetic acid, oxalic acid, sulfuric acid, hydrochloric acid, phenolsulfonic acid, p-toluenesulfonic acid, zinc acetate, manganese acetate, etc. may be mentioned. These acid catalysts can be used alone or in combination of two or more. Among these acid catalysts, sulfuric acid and p-toluenesulfonic acid are preferred from the viewpoint of excellent activity. The acid catalyst may be added before the reaction or during the reaction.
[0028] The polycondensation of a divalent phenol compound and an aromatic aldehyde may obtain a polycondensate in the presence of a solvent if necessary. Examples of the solvent include monoalcohols such as methanol, ethanol, and propanol; polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, trimethylene glycol, diethylene glycol, polyethylene glycol, and glycerin; glycol ethers such as 2-ethoxyethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monopentyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl methyl ether, and ethylene glycol monophenyl ether; cyclic ethers such as 1,3-dioxane, 1,4-dioxane, and tetrahydrofuran; glycol esters such as ethylene glycol acetate; and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, etc. These solvents can be used alone or in combination of two or more. Among these solvents, 2-ethoxyethanol is preferred from the viewpoint of excellent solubility of the obtained compound.
[0029] The reaction temperature for the polycondensation of a divalent phenol compound and an aromatic aldehyde is in the range of 20 to 140 °C, preferably in the range of 80 to 110 °C.
[0030] The charging ratio of the divalent phenol compound to the aromatic aldehyde is in the range of 1 / 0.1 to 1 / 0.5 in molar ratio, and more preferably in the range of 1 / 0.2 to 1 / 0.4, because the phenol compound after the reaction can be easily removed by reprecipitation or the like.
[0031] The method for producing the epoxy resin of the present invention by the reaction of a polyvalent hydroxy resin represented by formula (2) above with epichlorohydrin will be described. This reaction can be carried out in the same manner as well as well known epoxidation reactions.
[0032] For example, one method involves dissolving the polyvalent hydroxy resin in excess epichlorohydrin, and then reacting it in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide at a temperature of 50 to 150°C, preferably 60 to 120°C, for 1 to 10 hours. The amount of epichlorohydrin used in this case is 0.8 to 2 moles, preferably 0.9 to 1.2 moles, per mole of hydroxyl groups in the polyvalent hydroxy resin. After the reaction is complete, the excess epichlorohydrin is removed by distillation, the residue is dissolved in a solvent such as toluene or methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and then the solvent is removed by distillation to obtain the target epoxy resin represented by the general formula (1). A catalyst such as a quaternary ammonium salt may be used when carrying out the epoxidation reaction.
[0033] The purity of the epoxy resin of the present invention, particularly the amount of hydrolyzable chlorine, should be low from the viewpoint of improving the reliability of the electronic components to which it is applied. Although not particularly limited, it is preferably 1000 ppm or less, and more preferably 500 ppm or less. In this invention, hydrolyzable chlorine refers to the value measured by the following method: Dissolve 0.5 g of the sample in 30 ml of dioxane, add 10 ml of 1 N-KOH, boil under reflux for 30 minutes, cool to room temperature, and then add 100 ml of 80% acetone water to obtain 0.002 N-AgNO ３ This value is obtained by performing a differential titration with an aqueous solution.
[0034] The epoxy resin composition of the present invention comprises an epoxy resin and a curing agent, and preferably contains the epoxy resin of the above general formula (1) as the epoxy resin component.
[0035] In addition to the epoxy resin of general formula (1) which is preferably used, the epoxy resin composition of the present invention may also contain other ordinary epoxy resins having two or more epoxy groups in the molecule. For example, bisphenol A, bisphenol F, 3,3',5,5'-tetramethyl-4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, fluorenebisphenol, 4,4'-biphenol, 3,3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl, 2,2'-biphenol, resorcinol, catechol, t-butylcatechol t-butylhydroquinone, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,4-dihydroxynaphthalene, 2,5-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,8-dihydroxy Naphthalene, allyl or polyallylated dihydroxynaphthalene, divalent phenols such as allylated bisphenol A, allylated bisphenol F, and allylated phenol novolac, or phenol novolac, bisphenol A novolac, o-cresol novolac, m-cresol novolac, p-cresol novolac, xylenol novolac, poly-p-hydroxystyrene, tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis Examples include trivalent or higher phenols such as (4-hydroxyphenyl)ethane, fluoroglycinol, pyrogallol, t-butylpyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2,4-benzenetriol, 2,3,4-trihydroxybenzophenone, phenol aralkyl resins, naphthol aralkyl resins, and dicyclopentadiene resins, or glycidyl ethers derived from halogenated bisphenols such as tetrabromobisphenol A. These epoxy resins can be used individually or in mixtures of two or more.
[0036] The epoxy resin composition of the present invention preferably contains at least 50 wt% of the epoxy resin component of the epoxy resin of the above general formula (1). More preferably, it contains at least 70 wt% of the total epoxy resin, and more preferably at least 75 wt%. If the proportion used is less than this, the moldability of the epoxy resin composition deteriorates, and the effect of improving the heat resistance, thermal conductivity, etc., of the cured product is small.
[0037] As curing agents used in the epoxy resin composition of the present invention, all commonly known curing agents for epoxy resins can be used, including dicyandiamides, acid anhydrides, polyhydric phenols, aromatics, and aliphatic amines. Among these, polyhydric phenols are preferred as curing agents in fields requiring high electrical insulation properties, such as semiconductor encapsulants. It is preferable to use the polyhydric hydroxy resin represented by the general formula (2) of the present invention as a curing agent. When using the polyhydric hydroxy resin of the present invention as a curing agent for epoxy resins, it is desirable to include 50 wt% or more of the polyhydric hydroxy resin of formula (2) as a curing agent. Specific examples of curing agents are shown below.
[0038] Examples of polyhydric phenols include dihydric phenols such as bisphenol A, bisphenol F, bisphenol S, fluorenebisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, and naphthalenediol, as well as trihydric or higher phenols represented by tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phenol novolac, o-cresol novolac, naphthol novolac, and polyvinylphenol. Furthermore, there are polyhydric phenolic compounds synthesized from dihydric phenols such as phenols, naphthols, bisphenol A, bisphenol F, bisphenol S, fluorenebisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, and naphthalenediol, and condensing agents such as formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, and p-xylylene glycol.
[0039] Examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhymic anhydride, dodecinyl succinic anhydride, nadic anhydride, and trimellitic anhydride.
[0040] Amine-based curing agents include aromatic amines such as 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylsulfone, m-phenylenediamine, and p-xylylenediamine, as well as aliphatic amines such as ethylenediamine, hexamethylenediamine, diethylenetriamine, and triethylenetetramine.
[0041] The epoxy resin composition described above can be used by mixing one or more of these curing agents.
[0042] The mixing ratio of epoxy resin to curing agent is preferably in the range of 0.8 to 1.5 in terms of equivalent weight of epoxy groups to functional groups in the curing agent. Outside this range, unreacted epoxy groups or functional groups in the curing agent remain after curing, which reduces the reliability of the sealing function and is therefore undesirable.
[0043] The epoxy resin composition of the present invention may appropriately contain oligomers or polymer compounds such as polyester, polyamide, polyimide, polyether, polyurethane, petroleum resin, indene resin, indene-coumarone resin, and phenoxy resin as other modifiers. The amount added is usually in the range of 1 to 30 parts by weight per 100 parts by weight of the total resin components.
[0044] The epoxy resin composition of the present invention may contain additives such as inorganic fillers, pigments, retardants, thixotropy-imparting agents, coupling agents, and fluidity-improving agents. Examples of inorganic fillers include silica powder such as spherical or crushed fused silica or crystalline silica, alumina powder, glass powder, or mica, talc, calcium carbonate, alumina, and hydrated alumina. When used in semiconductor encapsulants, the preferred blending amount is 70% by weight or more, and more preferably 80% by weight or more.
[0045] To improve thermal conductivity, inorganic fillers such as glass cloth, carbon fiber, alumina, and boron nitride may be incorporated.
[0046] For the purpose of providing a higher thermal conductivity, the inorganic filler is preferably one with a high thermal conductivity. Preferably, it is 20 W / m·K or higher, more preferably 30 W / m·K or higher, and even more preferably 50 W / m·K or higher. At least a portion of the inorganic filler, preferably 50 wt% or more, has a thermal conductivity of 20 W / m·K or higher. The preference for the average thermal conductivity of the inorganic filler as a whole increases in the order of 20 W / m·K or higher, 30 W / m·K or higher, and 50 W / m·K or higher.
[0047] Examples of inorganic fillers with such thermal conductivity include inorganic powder fillers such as boron nitride, aluminum nitride, silicon nitride, silicon carbide, titanium nitride, zinc oxide, tungsten carbide, alumina, and magnesium oxide.
[0048] Pigments include organic or inorganic extender pigments and flake pigments. Examples of thixotropy-imparting agents include silicone-based, castor oil-based, aliphatic amide wax, oxidized polyethylene wax, and organic bentonite-based agents.
[0049] A curing accelerator may be used in the epoxy resin composition of the present invention as needed. Examples include amines, imidazoles, organophosphines, Lewis acids, etc. Specifically, these include tertiary amines such as 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; organophosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine; tetra-substituted phosphonium tetra-substituted borates such as tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium ethyltriphenylborate, and tetrabutylphosphonium tetrabutylborate; and tetraphenylborone salts such as 2-ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate. The amount added is typically in the range of 0.01 to 5 parts by weight per 100 parts by weight of the total resin components.
[0050] Furthermore, if necessary, the epoxy resin composition of the present invention may contain release agents such as carnauba wax and OP wax, coupling agents such as γ-glycidoxypropyltrimethoxysilane, colorants such as carbon black, flame retardants such as antimony trioxide, stress reducers such as silicone oil, lubricants such as calcium stearate, and the like.
[0051] The epoxy resin composition of the present invention can be prepared as a varnish by dissolving an organic solvent, then impregnated into fibrous materials such as glass cloth, aramid nonwoven fabric, or polyester nonwoven fabric such as liquid crystal polymer, and then the solvent is removed to form a prepreg. Alternatively, it can be applied to sheet materials such as copper foil, stainless steel foil, polyimide film, or polyester film to form a laminate.
[0052] The epoxy resin composition of the present invention can be heated and cured to obtain a cured resin product of the present invention. The method of forming this cured product is not limited, but for example, the epoxy resin composition can be molded by methods such as casting, compression molding, or transfer molding. The temperature at which this is done is usually in the range of 120 to 220°C.
[0053] The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to these. Unless otherwise specified, "parts" refers to parts by weight, and "%" refers to percentage by weight. The measurements were taken using the following methods.
[0054] 1) An epoxy equivalent potentiometric titrator was used, with methyl ethyl ketone as the solvent, and brominated tetraethylammonium acetate solution was added. The titration was then performed using a potentiometric titrator with a 0.1 mol / L perchloric acid-acetic acid solution.
[0055] 2) OH equivalent (hydroxyl group equivalent) Using a potentiometric titrator, 1,4-dioxane was used as the solvent, and acetylation was performed with 1.5 mol / L acetyl chloride. The excess acetyl chloride was decomposed with water, and the titration was performed using 0.5 mol / L potassium hydroxide.
[0056] 3) Softening point: Measured using the ring-and-ball method in accordance with JIS K-2207.
[0057] 4) A GPC measurement unit (Tosoh Corporation, HLC-8220GPC) was used, with four TSKgel SuperMultiporeHZ-N columns (Tosoh Corporation) connected in series. The column temperature was set to 40°C. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 0.35 mL / min, and a differential refractive index detector was used. For the measurement sample, 0.1 g of the sample was dissolved in 10 mL of THF, filtered through a microfilter, and 50 μL of the resulting sample was used. Data processing was performed using Tosoh Corporation's GPC-8020 Model II version 6.00.
[0058] 5) Solvent solubility (precipitation temperature) 2 g of resin composition and 1 g of methyl ethyl ketone were weighed into a sample bottle, heated and dissolved, and then the temperature was gradually lowered in a constant temperature bath. The temperature in the bath where the resin precipitated was measured. The higher the precipitation temperature (°C), the lower the solvent solubility.
[0059] 6) Glass transition temperature (Tg) The Tg was determined using a thermomechanical thermometer (EXSTAR TMA / 7100, manufactured by SII Nanotechnology Co., Ltd.) under a heating rate of 10°C / min.
[0060] 7) The 5% weight loss temperature (Td5) and residual carbon percentage were measured using a thermogravimetric / differential thermal analyzer (EXSTAR TG / DTA7300, manufactured by SII Nanotechnology) under a nitrogen atmosphere and a heating rate of 10°C / min. The weight loss at 700°C was also measured and calculated as the residual carbon percentage.
[0061] 8) Thermal conductivity: Thermal conductivity was measured using the transient hot-wire method with a NETZSCH LFA447 thermal conductivity meter.
[0062] (Example 1) In a 1000 mL four-necked flask, 84.1 g (0.60 mol) of 2-methoxyhydroquinone (structural formula below) was added. 4-Methoxybenzaldehyde (structural formula below) 27.2 g (0.20 mol) The mixture was prepared and dissolved in 450.0 g of 2-ethoxyethanol. While cooling in an ice bath, 9.8 g of sulfuric acid was added, and the mixture was heated and stirred at 100°C for 3 hours to allow the reaction to proceed. After the reaction, the resulting solution was reprecipitation with water, washed with water, filtered, and vacuum dried to obtain 71.7 g of polyvalent hydroxy resin a. Polyvalent hydroxy resin a is represented by R in formula (2). １ and R ２ is a methoxy group, R ３ and R ４ The atoms were hydrogen atoms, the number-average molecular weight was 190, the total GPC area percentage for n=1 was 98.7%, and the hydroxyl group equivalent was 107 g / eq. The GPC chart of the obtained polyvalent hydroxy resin a is shown in Figure 1.
[0063] (Example 2) Instead of 27.2 g of 4-methoxybenzaldehyde, 36.4 g (0.20 mol) of syringaldehyde (3,5-dimethoxy-4-hydroxybenzaldehyde, see structural formula below) was used. Except for using , the same procedure as in Synthesis Example 1 was carried out to obtain 81.8 g of polyvalent hydroxy resin b. Polyvalent hydroxy resin b is R in formula (2). １ ~R ３ Both are methoxy groups, R ４ The group is a hydroxyl group (OH group), with a number-average molecular weight of 220, a total GPC area percentage of n=1 of 99.1%, and a hydroxyl group equivalent of 92 g / eq.
[0064] (Example 3) Instead of 27.2 g of 4-methoxybenzaldehyde, use 21.2 g (0.20 mol) of benzaldehyde (structural formula below). Except for using , the same procedure as in Synthesis Example 1 was carried out to obtain 67.0 g of polyvalent hydroxy resin c. Polyvalent hydroxy resin c is R in formula (2). １ R is a methoxy group. ２ ~R ４ All of these were hydrogen atoms, with a number-average molecular weight of 200, a total GPC area percentage of n=1 of 97.9%, and a hydroxyl group equivalent of 93 g / eq.
[0065] (Example 4) Place 64.2 g (0.6 equivalents) of the hydroxy resin a obtained in Example 1 and 330 g of epichlorohydrin (structural formula below) into a 1000 ml four-necked flask. Adding the following, 50.0 g of a 48% sodium hydroxide aqueous solution was added dropwise over 4 hours at 62°C under reduced pressure (approximately 130 Torr). During this time, the water produced was removed from the system by azeotrope with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the dropwise addition was complete, the reaction was continued for another hour. Subsequently, the epichlorohydrin was removed by distillation, methyl isobutyl ketone was added, the salt was removed by washing with water, followed by filtration and washing with water, and then the methyl isobutyl ketone was removed by distillation under reduced pressure to obtain 80.2 g of epoxy resin (epoxy resin A). The epoxy equivalent of epoxy resin A was 167 g / eq., the softening point was 51°C, the hydrolyzable chlorine content was 150 ppm, the number average molecular weight was 220, and the n=1 compound measured by GPC was 79.0%. The GPC chart of the obtained epoxy resin A is shown in Figure 2.
[0066] (Example 5) The same procedure as in Example 4 was carried out, except that 55.2 g (0.60 equivalents) of hydroxy resin b obtained in Example 2 was used instead of hydroxy resin a, and 71.9 g of epoxy resin was obtained (epoxy resin B). The epoxy equivalent of epoxy resin B was 148 g / eq., the softening point was 65°C, the hydrolyzable chlorine was 100 ppm, the number average molecular weight was 240, and the n=1 compound measured by GPC was 82.0%.
[0067] (Example 6) The same procedure as in Example 4 was carried out, except that 55.8 g (0.60 equivalents) of hydroxy resin c obtained in Example 3 was used instead of hydroxy resin a, and 75.1 g of epoxy resin was obtained (Epoxy Resin C). The epoxy equivalent of epoxy resin C was 150 g / eq., the softening point was 55°C, the hydrolyzable chlorine content was 120 ppm, the number average molecular weight was 200, and the n=1 compound measured by GPC was 79.0%.
[0068] (Reference Example 1) In a 1000 mL four-necked flask, 66.1 g (0.60 mol) of hydroquinone (structural formula below) Benzaldehyde (structural formula below) 21.2 g (0.20 mol) The mixture was prepared and dissolved in 200.0 g of 2-ethoxyethanol. While cooling in an ice bath, 19.6 g of sulfuric acid was added, and the mixture was heated and stirred at 100°C for 3 hours to allow the reaction to proceed. After the reaction, the resulting solution was reprecipitation with water, washed with water, filtered, and vacuum dried to obtain 60.0 g of polyvalent hydroxy resin d. In formula (2), R １ ~R ４ All of these were hydrogen atoms, with a number-average molecular weight of 740, a GPC area percentage of n=1 of 22.6%, and a hydroxyl group equivalent of 100 g / eq. Using 60.0 g (0.6 equivalents) of the obtained polyvalent hydroxy resin d, the same procedure as in Example 4 was carried out to obtain 73.9 g of epoxy resin (epoxy resin D). The epoxy equivalent of epoxy resin D was 167 g / eq., the softening point was 84°C, the hydrolyzable chlorine content was 70 ppm, the number-average molecular weight was 880, and the n=0 isomer was 3.6% and the n=1 isomer was 16.9% as measured by GPC.
[0069] (Reference example 2) The same procedure as in Example 4 was followed, except that 58.4 g (0.60 equivalents) of 4,4',4"-trihydroxytriphenylmethane (the above structural formula) was used instead of hydroxy resin a, to obtain 86.9 g of epoxy resin (epoxy resin E). The epoxy equivalent of epoxy resin E was 155 g / eq., the softening point was 50°C, the hydrolyzable chlorine content was 40 ppm, the number average molecular weight was 410, and the n=0 isomer (trifunctional type) accounted for 98.0% of the GPC area%.
[0070] (Reference Example 3) 55.1 g of 4,4'-dihydroxybiphenyl, 23.6 g of 2,2'-dihydroxybiphenyl, 121.2 g of diethylene glycol dimethyl ether, and 42.5 g of 4,4'-bischloromethylbiphenyl were charged into a 1000 ml four-necked flask. The mixture was heated to 170°C under a nitrogen stream with stirring and reacted for 10 hours to produce a polyvalent hydroxy resin. After the reaction was complete, 50.7 g of diethylene glycol dimethyl ether was recovered, 470 g of epichlorohydrin was added, and 68.7 g of 48% sodium hydroxide aqueous solution was added dropwise over 4 hours at 62°C under reduced pressure (approximately 130 Torr). During this time, the water produced was removed from the system by azeotrope with the epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the dropwise addition was complete, the reaction was continued for another hour. Subsequently, epichlorohydrin was removed by distillation, methyl isobutyl ketone was added, the salt was removed by washing with water, followed by filtration and washing with water, and then methyl isobutyl ketone was removed by vacuum distillation to obtain 130 g of epoxy resin (epoxy resin F, structural formula below). The epoxy equivalent of this epoxy resin F was 196, the softening point was 97°C, and the hydrolyzable chlorine content was 65 ppm. The percentage of n≧1 components measured by GPC was 72.0% (28.0% of n=0 components and 13.3% of n=1 components).
[0071] Examples 7-12, Comparative Examples 1-4: Epoxy resins A-C obtained in Examples 4-6, epoxy resins D-F obtained in Reference Examples 1-3, and epoxy resin G (o-cresol novolac type epoxy resin, YDCN-700-3, manufactured by Nippon Steel Chemical & Material, epoxy equivalent 200) were used as epoxy resin components. Polyvalent hydroxy resins a-b obtained in Examples 1-2 and phenol novolac resin curing agent g (hydroxyl group equivalent 105 g / eq.) were used as curing agents (curing agents a-b, g), and triphenylphosphine was used as a curing accelerator. Epoxy resin compositions were obtained with the formulations shown in Table 1. The values in the table represent parts by weight in the formulation. These epoxy resin compositions were molded at 175°C, post-cured at 175°C for 5 hours, and cured specimens were obtained, which were then subjected to various physical property measurements.
[0072] When using the epoxy resin and polyvalent hydroxy resin curing agent in the examples, the materials exhibited superior physical properties compared to the comparative examples, including excellent solvent solubility, high thermal conductivity, and high heat resistance.
[0073]
[0074] The polyvalent hydroxy resin and epoxy resin of the present invention are suitable for power devices and automotive applications because they have excellent solvent solubility, high heat resistance, and good thermal conductivity.
Claims
1. An epoxy resin represented by the following general formula (1), wherein the content of n=1 is 50% or more in area percent as measured by gel permeation chromatography. In formula (1), R １ R independently represents a hydrogen atom, a fluorine atom, an alkoxy group, or a monovalent hydrocarbon group having 1 to 6 carbon atoms. ２ ~R ４ Each of these independently represents a hydrogen atom, a fluorine atom, an alkoxy group, a monovalent C1-C6 hydrocarbon group, or a glycidyl ether group. n represents a number from 1 to 5.
2. A polyhydroxy resin represented by the following general formula (2) and having a content of n = 1 of 50% or more in area% measured by gel permeation chromatography. In the formula (2), R １ independently represents a hydrogen atom, a fluorine atom, an alkoxy group or a monovalent hydrocarbon group having 1 to 6 carbon atoms. R ２ to R ４ each independently represents a hydrogen atom, a fluorine atom, an alkoxy group, a monovalent hydrocarbon group having 1 to 6 carbon atoms or a hydroxy group. n represents a number from 1 to 5.
3. The epoxy resin according to claim 1, characterized in that it is obtained by reacting a phenol compound with an aromatic aldehyde and epichlorohydrin, wherein either or both of the phenol compound and the aromatic aldehyde are of plant origin.
4. The polyhydric hydroxy resin according to claim 2, characterized in that it is obtained by reacting a phenol compound with an aromatic aldehyde, and either or both of the phenol compound and the aromatic aldehyde are of plant origin.
5. An epoxy resin composition comprising an epoxy resin and a curing agent, characterized in that the epoxy resin described in claim 1 is included as an essential component as part or all of the epoxy resin.
6. An epoxy resin composition comprising an epoxy resin and a curing agent, characterized in that the polyvalent hydroxy resin described in claim 2 is included as an essential component as part or all of the curing agent.
7. A cured resin product characterized by being obtained by curing the epoxy resin composition according to claim 5 or 6.