Polyvalent hydroxy resins, epoxy resins, epoxy resin compositions, and cured products thereof

Abstract

To provide an epoxy resin that gives a cured product having thermal stability, high thermal conductivity, low thermal expandability or the like, and is useful for applications such as lamination, molding, casting, bonding.SOLUTION: An epoxy resin is represented by general formula (1) and has an epoxy equivalent of 180-230 g / eq and a softening point of 60-120°C (where, n is a number selected from 0-20, R1's each represent a hydrogen atom or OG group, G's each represent a glycidyl group, and R2's each represent a hydrogen atom or a C1-10 monovalent hydrocarbon group, with at least some of R1's being OG groups).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to polyvalent hydroxy resins, epoxy resins, epoxy resin compositions, and epoxy resin cured products, and more specifically to polyvalent hydroxy resins, epoxy resins, and epoxy resin compositions that are useful as insulating materials for electrical and electronic components such as semiconductor encapsulants, laminates, and heat dissipation substrates, and that have excellent handling properties as solids at room temperature, low viscosity during molding, and solvent solubility, as well as to epoxy resin cured products obtained by curing them that have excellent heat resistance, thermal decomposition stability, and thermal conductivity. [Background technology]

[0002] Epoxy resins have been used in a wide range of industrial applications, but the performance requirements for them have become increasingly sophisticated in recent years. In this context, power devices, which have been under development in recent years, require further improvements in power density. As a result, the surface temperature of the chip during operation exceeds 200°C, and therefore, the development of encapsulating materials that can withstand such temperatures is desired.

[0003] In this context, Patent Document 1 discloses an epoxy resin, epoxy resin composition, and cured product having a biphenol-biphenylaralkyl structure, demonstrating excellent heat resistance, moisture resistance, and thermal conductivity. Patent Document 2 also discloses an epoxy resin composition, a method for producing an epoxy resin cured product, and a semiconductor device having a biphenol-biphenylaralkyl structure, demonstrating that a cured product with excellent heat resistance and thermal decomposition stability can be obtained. However, its handling is hampered by its crystalline nature, exhibiting a melting point of over 100°C. Therefore, mixing with curing agents requires high-temperature melting and kneading. At high temperatures, the curing reaction between the epoxy resin and curing agent proceeds rapidly, shortening the gelation time, thus severely limiting the mixing process. Furthermore, its strong crystallinity presents challenges in solvent solubility, making application to laminates difficult. Patent Document 3 proposes reducing the crystallinity of an epoxy resin having a biphenol-biphenylaralkyl structure by removing the crystalline component, but its solvent solubility is insufficient, posing practical challenges. 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 4 proposes a composition that can maintain these physical properties, but its strong crystallinity makes melt kneading difficult, and its solvent solubility is insufficient for practical use in laminate applications. Patent Document 5 discloses a structure in which hydrocarbon groups are modified in a biphenylaralkyl resin, which is expected to improve solvent solubility, but its heat resistance is insufficient, and there is no mention of thermal conductivity. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] WO2011 / 074517 publication [Patent Document 2] WO2014 / 065152 publication [Patent Document 3] Japanese Patent Publication No. 2017-95524 [Patent Document 4] Japanese Patent Publication No. 2015-160893 [Patent Document 5] Japanese Patent Application Publication No. 11-124428 [Overview of the project] [Problems that the invention aims to solve]

[0005] An object of the present invention is to provide an epoxy resin composition useful for encapsulating electrical and electronic components, circuit board materials, etc., which gives a cured product excellent in melt kneadability, solvent solubility, heat resistance, thermal decomposition stability, and thermal conductivity in applications such as lamination, molding, casting, and adhesion, and to provide a cured product thereof. Another object is to provide an epoxy resin used in this epoxy resin composition and a polyhydric hydroxy resin suitable as an intermediate of this epoxy resin.

Means for Solving the Problems

[0006] The present inventors have intensively studied and found that an epoxy resin having a specific structure is expected to solve the above problems, and that its cured product exhibits effects on heat resistance, thermal decomposition stability, and thermal conductivity.

[0007] That is, the present invention is an epoxy resin represented by the following general formula (1), wherein the epoxy equivalent is 180 to 210 g / eq and the softening point is in the range of 60 to 120 °C.

Chemical formula

[0008] The above R 1 is a hydrogen atom or an OG group, and it is suitable that the proportion of hydrogen atoms in R 1 is 1 to 20 mol%. Also, the biphenyl ring having an OG group as R 1 is preferably bonded to two OG groups at 4,4'.

[0009] Further, the present invention relates to 4,4'-dihydroxybiphenyl andA method for producing the above epoxy resin, characterized in that it is obtained by reacting a mixture containing hydroxybiphenyl with an aromatic crosslinking agent having a biphenyl structure to form a polyhydroxy resin, and then reacting epichlorohydrin. Examples of the aromatic crosslinking agent include 4,4'-bis(chloromethyl)biphenyl.

[0010] Furthermore, the present invention relates to a polyhydroxy resin represented by the following general formula (2), wherein the OH equivalent is in the range of 130 to 160 g / eq. [Chemical formula] (Here, n represents a number from 0 to 20, However, the mean value of n is greater than 0. R 3 represents a hydrogen atom or an OH group, and R 2 represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. At least a part of R 3 is an OH group.)

[0011] In addition, the present invention relates to an epoxy resin composition characterized by comprising the above epoxy resin and a curing agent as essential components. Furthermore, the present invention relates to an epoxy resin cured product characterized by curing this epoxy resin. composition [Advantages of the Invention]

[0012] The epoxy resin of the present invention has good melt kneading properties at 100°C or lower and excellent solvent solubility, so it is suitable for epoxy resin compositions and their cured products used in applications such as lamination, molding, casting, and adhesion. And this cured product has excellent heat resistance, thermal decomposition stability, and thermal conductivity, so it is suitable for encapsulation of electrical and electronic components, circuit board materials, etc. [Brief Description of the Drawings]

[0013] [Figure 1] GPC chart of the epoxy resin obtained in Example 2 [Modes for Carrying Out the Invention]

[0014] Hereinafter, the present invention will be described in detail.

[0015] The epoxy resin of the present invention is represented by the above general formula (1), and the epoxy equivalent (g / eq) is 180 to 210. n is the repeating number (number average), indicating a number from 0 to 20, and G is a glycidyl group. Preferably, it is a mixture of components with different values of n. In the general formula (1), R 1 represents a hydrogen atom or an OG group, and at least a part of R 1 is an OG group. R 2 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Since R 1 is a hydrogen atom or an OG group, the biphenyl ring having R 1 will include a biphenyl ring having two OG groups and a biphenyl ring having one OG group. The biphenyl ring having two OG groups is preferably a 4,4'-isomer (a unit having a structure bonded to an OG group at the 4,4'-position). For the biphenyl ring having one OG group where R 1 is a hydrogen atom, it is preferably 1 to 20 mol% of the total biphenyl rings having R 1 , and more preferably 5 to 15 mol%. Also, the biphenyl ring having two OG groups is preferably 80 to 99 mol% of the total biphenyl rings having R 1 , and more preferably 85 to 95 mol%. If the biphenyl ring having one OG group is more than 20 mol%, there is concern about a decrease in heat resistance due to a decrease in the crosslinking density of the cured product. Also, by including the biphenyl ring having one OG group, it has excellent fluidity and an improvement in solvent solubility is expected.

[0016] The softening point of the epoxy resin of the present invention is in the range of 60 to 120°C. If the softening point is lower than 60°C, it will be a liquid or semi-solid epoxy resin, making handling difficult. If it is higher than 120°C, the melt kneading property will decrease, and in the case of having crystallinity, the solvent solubility will also decrease.

[0017] The epoxy resin of the present invention can be produced by reacting a polyvalent hydroxy resin represented by the above general formula (2) with epichlorohydrin. In general formula (2), R 3 R represents a hydrogen atom or an OH group, and at least part of it is an OH group. 2 This is equivalent to general formula (1). This polyvalent hydroxy resin is also the polyvalent hydroxy resin of the present invention, R 3 The biphenyl rings containing this include biphenyl rings with two OH groups and biphenyl rings with one OH group. 3 The preferred amount of R in the epoxy resin is 1 This is similar to the abundance of [something].

[0018] Furthermore, this polyvalent hydroxy resin can be produced by reacting biphenols with an aromatic condensing agent having a biphenyl structure represented by the following formula (3). [ka] (Here, X represents a hydroxyl group, a halogen atom, or an alkoxy group having 1 to 6 carbon atoms.)

[0019] The biphenols used as raw materials for the synthesis of polyvalent hydroxy resins are mixtures of dihydroxybiphenyls and hydroxybiphenyls. Examples of dihydroxybiphenyls include 4,4'-dihydroxybiphenyl and 2,2'-dihydroxybiphenyl. 4,4'-dihydroxybiphenyl gives the 4,4'-isomer, and 2,2'-dihydroxybiphenyl gives the 2,2'-isomer. When only 4,4'-dihydroxybiphenyl is used, the crystallinity is high. From the viewpoint of improving the heat resistance and thermal conductivity of the cured product, 4,4'-dihydroxybiphenyl is preferred. On the other hand, from the viewpoint of solvent solubility, 2,2'-dihydroxybiphenyl is preferred.

[0020] When using 4,4'-dihydroxybiphenyl and 2,2'-dihydroxybiphenyl in combination, it is preferable to use a mixture of dihydroxybiphenyls containing 30-90% by weight of 4,4'-dihydroxybiphenyl and 10-70% by weight of 2,2'-dihydroxybiphenyl. Preferably, a mixture of dihydroxybiphenyls containing 50-90% by weight of 4,4'-dihydroxybiphenyl and 10-50% by weight of 2,2'-dihydroxybiphenyl is used. The mixture of dihydroxybiphenyls may contain other dihydroxybiphenyls, but it is preferable that they be present in amounts of 10-50% by weight or less.

[0021] Examples of hydroxybiphenyls include 2-phenylphenol, 4-phenylphenol, 3-benzyl-1,1'-biphenyl-2-ol, 3-benzyl-1,1'-biphenyl-4-ol, 3-phenylphenol, and 2,6-diphenylphenol. 2-phenylphenol and 4-phenylphenol are preferred in terms of reactivity and supplyability.

[0022] Hydroxybiphenyls have substituents R 2 It has R 2 The group is preferably a hydrogen atom, an alkyl group, or an aralkyl group. The alkyl group is preferably a methyl group or an ethyl group, and the aralkyl group is preferably a benzyl group. Also, R 1 or R 3 If it is anything other than an OG group or an OH group, it is a hydrogen atom.

[0023] The mixing ratio of dihydroxybiphenyls and hydroxybiphenyls in the raw materials is preferably 1 to 20 mol% of hydroxybiphenyls, and more preferably 5 to 15 mol%, relative to the total weight of dihydroxybiphenyls and hydroxybiphenyls. If the proportion of hydroxybiphenyls is greater than 20 mol%, the crosslinking density of the cured product decreases, which may lead to a decrease in heat resistance. In addition, the inclusion of hydroxybiphenyl rings is expected to provide excellent fluidity and improved solvent solubility. In terms of weight ratio, it is preferably 1 to 30% by weight of hydroxybiphenyls, and more preferably 3 to 15% by weight, relative to the total weight of dihydroxybiphenyls and hydroxybiphenyls.

[0024] In formula (3) above, X represents a hydroxyl group, a halogen atom, or an alkoxy group having 1 to 6 carbon atoms. Specific examples of aromatic condensing agents include 4,4'-bishydroxymethylbiphenyl, 4,4'-bischloromethylbiphenyl, 4,4'-bisbromomethylbiphenyl, 4,4'-bismethoxymethylbiphenyl, and 4,4'-bisethoxymethylbiphenyl. From the viewpoint of reactivity, 4,4'-bishydroxymethylbiphenyl or 4,4'-bischloromethylbiphenyl are preferred, and from the viewpoint of reducing ionic impurities, 4,4'-bishydroxymethylbiphenyl or 4,4'-bismethoxymethylbiphenyl are preferred.

[0025] The molar ratio when reacting biphenols with aromatic condensing agents is generally in the range of 0.1 to 0.5 moles of aromatic condensing agent per mole of biphenol, more preferably in the range of 0.2 to 0.4 moles. If the ratio is less than 0.1 moles, the proportion of n=0 polyvalent hydroxy resin obtained will be high, raising concerns about reduced solubility, such as crystallinity. On the other hand, if the ratio is more than 0.5 moles, the molecular weight will increase, raising the softening point and melt viscosity, which will impair handling and moldability.

[0026] The reaction between biphenols and aromatic condensing agents can be carried out without a catalyst or in the presence of an acid catalyst such as an inorganic or organic acid. When using 4,4'-bischloromethylbiphenyl, the reaction can be carried out without a catalyst, but generally, it is preferable to carry out the reaction in the presence of an acid catalyst to suppress side reactions such as the formation of ether bonds by the reaction of chloromethyl groups and hydroxyl groups. As this acid catalyst, it can be appropriately selected from well-known inorganic and organic acids, for example, mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; organic acids such as formic acid, oxalic acid, trifluoroacetic acid, p-toluenesulfonic acid, metasulfonic acid, and trifluorometasulfonic acid; Lewis acids such as zinc chloride, aluminum chloride, iron chloride, and boron trifluoride; or solid acids.

[0027] Typically, this reaction is carried out at 100-250°C for 1-20 hours. Preferably, it is carried out at 100-180°C, and more preferably at 140-180°C. If the reaction temperature is too low, the reactivity is poor and it takes too long, and if the reaction temperature is too high, there is a risk of resin decomposition.

[0028] As solvents used in the reaction, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, diethylene glycol dimethyl ether, and triglime, or aromatic compounds such as benzene, toluene, chlorobenzene, and dichlorobenzene are often used, with ethyl cellosolve, diethylene glycol dimethyl ether, and triglime being particularly preferred. After the reaction is complete, the obtained polyvalent hydroxy resin may have the solvent removed by methods such as vacuum distillation, washing with water, or reprecipitation in a poor solvent, but it may also be used as a raw material for the epoxidation reaction with the solvent still present.

[0029] The polyvalent hydroxy resin obtained in this way can be used not only as a raw material for epoxy resins, but also as an epoxy resin curing agent. Furthermore, by combining it with curing agents such as hexamine, it can also be applied as a phenolic resin molding material.

[0030] The method for producing the epoxy resin of the present invention by the reaction of a polyvalent hydroxy resin represented by the above general formula (2) with epichlorohydrin will be described. This reaction can be carried out in the same manner as well as well known epoxidation reactions.

[0031] For example, the polyvalent hydroxy resin is dissolved in excess epichlorohydrin, and then reacted at 50 to 150°C, preferably 60 to 120°C, for 1 to 10 hours in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. 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.

[0032] 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: 0.5 g of the sample is dissolved in 30 ml of dioxane, 10 ml of 1N-KOH is added, boiled under reflux for 30 minutes, cooled to room temperature, 100 ml of 80% acetone water is added, and the value is obtained by potentiometric titration with a 0.002 N-AgNO3 aqueous solution.

[0033] The epoxy resin composition of the present invention comprises an epoxy resin and a curing agent, and includes the epoxy resin of general formula (1) described above as the epoxy resin component.

[0034] In addition to the epoxy resin of general formula (1) used as an essential component, the epoxy resin composition of the present invention may also contain other ordinary epoxy resins having two or more epoxy groups in their molecules. Examples include 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, and 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 Examples include naphthalene, allyl or polyallylated dihydroxynaphthalene, divalent phenols such as allylated bisphenol A, allylated bisphenol F, and allylated phenol novolac, or trivalent or higher phenols such as 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(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 combination of two or more types.

[0035] The epoxy resin composition of the present invention preferably contains at least 50 wt% of the epoxy resin component of the epoxy resin represented by the above general formula (1). More preferably, it contains at least 70 wt% of the total epoxy resin, and more preferably at least 80 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.

[0036] 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. Specific examples of curing agents are shown below.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] The epoxy resin composition described above can be used by mixing one or more of these curing agents.

[0041] 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.

[0042] 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.

[0043] Furthermore, 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 and 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.

[0044] 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.

[0045] Furthermore, 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.

[0046] 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.

[0047] 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.

[0048] The epoxy resin composition of the present invention can be heated and cured to produce a cured resin product of the present invention. This cured product can be obtained by molding the epoxy resin composition by methods such as casting, compression molding, or transfer molding. The temperature during this process is typically in the range of 120 to 220°C. [Examples]

[0049] The present invention will be specifically described below with reference to synthesis examples, 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.

[0050] 1) Measurement of epoxy equivalent Using a potentiometric titrator, methyl ethyl ketone was used as the solvent, and brominated tetraethylammonium acetate solution was added. The results were then measured using a 0.1 mol / L perchloric acid-acetic acid solution via a potentiometric titrator.

[0051] 2) Measurement of OH 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.

[0052] 3) Melt viscosity The measurement was taken at 150°C using a Brookfield CAP2000H rotational viscometer.

[0053] 4) Softening point Measurements were taken using the ring-sphere method in accordance with JIS-K-2207.

[0054] 5) GPC measurement A system consisting of a main unit (Tosoh Corporation, HLC-8220GPC) and columns (Tosoh Corporation, TSKgelG4000HXL, TSKgelG3000HXL, TSKgelG2000HXL) connected in series was used, with the column temperature set to 40°C. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 1 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.

[0055] 6) Glass transition temperature (Tg) Tg was determined using a thermomechanical measuring device (EXSTAR6000TMA / 6100, manufactured by SII Nanotechnology Co., Ltd.) under a heating rate of 10°C / min.

[0056] 7) 5% weight loss temperature (Td5), residual coal rate Using a thermogravimetric / differential thermal analyzer (SII Nanotechnology EXSTAR6000TG / DTA6200), the 5% weight loss temperature (Td5) was measured 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.

[0057] 8) Thermal conductivity Thermal conductivity was measured using the transient hot-wire method with a NETZSCH LFA447 thermal conductivity meter.

[0058] Example 1 In a 1000 ml four-necked flask, 3.0 g of 2-phenylphenol, 62.0 g of 4,4'-dihydroxybiphenyl, 100.2 g of diethylene glycol dimethyl ether, and 35.2 g of 4,4'-bischloromethylbiphenyl were charged. The mixture was heated to 170°C under a nitrogen stream with stirring and reacted for 3 hours to produce a polyvalent hydroxy resin with an OH equivalent of 136 g / eq. After the reaction was complete, 43.3 g of diethylene glycol dimethyl ether was recovered, and 379.7 g of epichlorohydrin was added. 58.2 g of 48% sodium hydroxide aqueous solution was added dropwise over 3 hours under reduced pressure (approximately 130 Torr) at 62°C. 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, toluene was added, followed by washing with water, filtration, and removal under reduced pressure to obtain 115 g of epoxy resin (epoxy resin A). The epoxy equivalent of epoxy resin A was 200 g / eq, the softening point was 110°C, the melt viscosity was 0.19 Pa·s, and the hydrolyzable chlorine content was 65 ppm. R in formula (2) of polyvalent hydroxy resin 3 The proportion of hydrogen atoms was 6.4 mol%. Also, in formula (1) of epoxy resin A, R 1 The proportion of hydrogen atoms was 6.4 mol%.

[0059] Example 2 In a 1000 ml four-necked flask, 6.3 g of 2-phenylphenol, 62.0 g of 4,4'-dihydroxybiphenyl, 105.5 g of diethylene glycol dimethyl ether, and 37.2 g of 4,4'-bischloromethylbiphenyl were charged. The mixture was heated to 170°C under a nitrogen atmosphere with stirring and reacted for 3 hours to produce a polyvalent hydroxy resin with an OH equivalent of 133 g / eq. After the reaction was complete, 46.7 g of diethylene glycol dimethyl ether was recovered, and 389.8 g of epichlorohydrin was added. 59.7 g of 48% sodium hydroxide aqueous solution was added dropwise over 3 hours under reduced pressure (approximately 130 Torr) at 62°C. 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 to epoxidize the mixture. Subsequently, epichlorohydrin was removed by distillation, toluene was added, followed by washing with water, filtration, and distillation under reduced pressure to obtain 121 g of epoxy resin (epoxy resin B). Epoxy resin B had an epoxy equivalent of 198 g / eq, a softening point of 92°C, a melt viscosity of 0.18 Pa·s, and a hydrolyzable chlorine content of 57 ppm. The GPC chart of the obtained resin is shown in Figure 1. R in formula (2) of polyvalent hydroxy resin 3 The proportion of hydrogen atoms was 3.8 mol%. Also, in formula (1) of epoxy resin B, R 1 The proportion of hydrogen atoms was 3.8 mol%.

[0060] Example 3 The reaction was carried out in the same manner as in Example 2, except that 4-phenylphenol was used instead of 2-phenylphenol. A polyvalent hydroxy resin with an OH equivalent of 138 g / eq was produced, and then epoxidized to obtain 120 g of epoxy resin (epoxy resin C). Epoxy resin C had an epoxy equivalent of 199 g / eq, a softening point of 98°C, a melt viscosity of 0.19 Pa·s, and a hydrolyzable chlorine content of 68 ppm. R in formula (2) of polyvalent hydroxy resin 3 The proportion of hydrogen atoms was 8.2 mol%. Also, in formula (1) of epoxy resin C, R 1 The proportion of hydrogen atoms was 8.2 mol%.

[0061] Example 4 The reaction was carried out in the same manner as in Example 1, except that 4.6 g of 3-benzyl-1,1'-biphenyl-2-ol was used instead of 2-phenylphenol. A polyvalent hydroxy resin with an OH equivalent of 143 g / eq was produced, which was then epoxidized to obtain 114 g of epoxy resin (epoxy resin D). Epoxy resin D had an epoxy equivalent of 203 g / eq, a softening point of 115°C, a melt viscosity of 0.19 Pa·s, and a hydrolyzable chlorine content of 82 ppm. R in formula (2) of polyvalent hydroxy resin 3 The proportion of hydrogen atoms was 7.0 mol%. Also, in formula (1) of epoxy resin D, R 1 The proportion of hydrogen atoms was 7.0 mol%.

[0062] Comparative Example 1 In a 1000 ml four-necked flask, 24.3 g of 2-phenylphenol, 62.0 g of 4,4'-dihydroxybiphenyl, 134.1 g of diethylene glycol dimethyl ether, and 47.8 g of 4,4'-bischloromethylbiphenyl were charged. The mixture was heated to 170°C under a nitrogen atmosphere with stirring and reacted for 3 hours to produce a polyvalent hydroxy resin with an OH equivalent of 163 g / eq. After the reaction was complete, 66.6 g of diethylene glycol dimethyl ether was recovered, and 448.7 g of epichlorohydrin was added. 68.7 g of 48% sodium hydroxide aqueous solution was added dropwise over 3 hours under reduced pressure (approximately 130 Torr) at 62°C. 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, toluene was added, followed by washing with water, filtration, and distillation under reduced pressure to obtain 130 g of epoxy resin (epoxy resin E). The epoxy equivalent of epoxy resin E was 226 g / eq, the softening point was 78°C, the melt viscosity was 0.16 Pa·s, and the hydrolyzable chlorine content was 90 ppm. R in formula (2) of polyvalent hydroxy resin 3 The proportion of hydrogen atoms was 30.4 mol%. Also, in formula (1) of epoxy resin E, R 1 The proportion of hydrogen atoms was 30.4 mol%.

[0063] Comparative Example 2 In a 1000ml four-necked flask, 77.5g of 4,4'-dihydroxybiphenyl, 119.3g of diethylene glycol dimethyl ether, and 41.8g of 4,4'-bischloromethylbiphenyl were charged and subjected to a nitrogen atmosphere. stirring The mixture was heated to 160°C and reacted for 20 hours to produce a polyvalent hydroxy resin with an OH equivalent of 135 g / eq. After the reaction was complete, 45.6 g of diethylene glycol dimethyl ether was recovered, 455.1 g of epichlorohydrin was added, and 70.5 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, 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 129 g of epoxy resin (epoxy resin F). The epoxy equivalent of epoxy resin F was 200 g / eq, the softening point was 125°C, the melt viscosity was 0.21 Pa·s, and the hydrolyzable chlorine content was 230 ppm. R in formula (2) of polyvalent hydroxy resin 3 The proportion of hydrogen atoms in equation (1) of epoxy resin F was 0 mol%. 1 The proportion of hydrogen atoms was 0 mol%.

[0064] Solvent solubility To determine solvent solubility, epoxy resins A-D obtained in Examples 1-4, and epoxy resins E and F obtained in Comparative Examples 1 and 2 were added to 5 g of solvent (methyl ethyl ketone, toluene, cyclohexanone) at a solid content concentration (g of epoxy resin / 100 g of solvent) of 10% by weight. After thorough stirring at room temperature, insoluble matter was visually inspected. × indicated the presence of insoluble matter, and ○ indicated its absence. △ indicated that insoluble matter was observed but dissolved upon heating to 60°C. The results are shown in Table 1.

[0065] [Table 1]

[0066] Examples 5-8 and Comparative Examples 3-5 As epoxy resin components, epoxy resins A to D obtained in Examples 1 to 4, epoxy resins E and F obtained in Comparative Examples 1 and 2, and o-cresol novolac type epoxy resin (YDCN-700-3, manufactured by Nippon Steel Chemical & Material, epoxy equivalent 200 g / eq, total chlorine 1600 ppm) were used as epoxy resin G. Triphenolmethane type polyvalent hydroxy resin (TPM-100, manufactured by Gun-ei Chemical Industry Co., Ltd., OH equivalent 98 g / eq, softening point 105°C) was used as the curing agent, and triphenylphosphine was used as the curing accelerator. Epoxy resin compositions were obtained with the formulations shown in Table 2. The values ​​in the table represent parts by weight in the formulation. To obtain uniform molded products, the melt-kneading temperature was 100°C for Examples 5 to 8 and Comparative Example 3, and 150°C for Comparative Example 4. Using this epoxy resin composition, molding was performed at 175°C, and post-curing was carried out at 175°C for 5 hours to obtain cured test pieces, which were then subjected to various physical property measurements.

[0067] [Table 2]

[0068] As is clear from these results, the epoxy resin obtained in the examples has excellent solvent solubility, low viscosity, and a low softening point, resulting in good moldability, and a uniform cured product can be obtained by melt kneading. Furthermore, the cured product has excellent heat resistance, thermal stability, and thermal conductivity. ru Therefore, it is suitable for electronic material applications such as substrates and encapsulating materials.

Claims

1. An epoxy resin represented by the following general formula (1), characterized in that it has an epoxy equivalent of 180 to 210 g / eq and a softening point in the range of 60 to 120°C. 【Chemistry 1】 (Here, n represents a number between 0 and 20, where the average value of n is greater than 0, R １ R independently represents a hydrogen atom or an OG group, and at least a portion of it is an OG group. １ The proportion of hydrogen atoms is 1 to 20 mol%. ２ (Each represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. G represents a glycidyl group.)

2. R is an OG group １ The epoxy resin according to claim 1, wherein the biphenyl ring having is a 4,4'-form.

3. A method for producing an epoxy resin according to claim 1 or 2, characterized in that a mixture containing 4,4'-dihydroxybiphenyl and hydroxybiphenyl is reacted with an aromatic crosslinking agent having a biphenyl structure to form a polyvalent hydroxy resin, and then reacted with epichlorohydrin.

4. A method for producing an epoxy resin according to claim 3, wherein the aromatic crosslinking agent is 4,4'-bischloromethylbiphenyl.

5. A polyvalent hydroxy resin represented by the following general formula (2), wherein the OH equivalent is in the range of 130 to 160 g / eq. 【Chemistry 2】 (Here, n represents a number between 0 and 20, where the average value of n is greater than 0, R ３ R represents a hydrogen atom or an OH group, and at least part of it is an OH group. ３ The proportion of hydrogen atoms is 1 to 20 mol%. ２ (This represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.)

6. An epoxy resin composition characterized by comprising the epoxy resin and curing agent described in claim 1 or 2 as essential components.

7. An epoxy resin cured product characterized by being obtained by curing the epoxy resin composition described in claim 6.

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