Crystalline epoxy resin, epoxy resin composition and epoxy resin cured product

Abstract

This invention provides a crystalline epoxy resin, an epoxy resin composition, and a cured epoxy resin. A crystalline epoxy resin is an epoxy resin represented by the following general formula (1), characterized in that the total of the components with n=0 and A being m=0 of general formula (a) and the components with n=0 and A being of general formula (b), as determined by GPC, is in the range of 40 area % to 85 area %, and in the structure of A in general formula (1), the presence proportion of the structure of m=0 of general formula (a) is 10 mol% or less.

Description

Technical Field

[0001] This invention relates to a crystalline epoxy resin with excellent reliability and effective use as an insulating material for electrical / electronic components such as semiconductor seals, laminates, and heat dissipation substrates; excellent workability as a solid at room temperature and excellent low viscosity during molding; epoxy resin compositions using the same; and cured products with excellent thermal conductivity and heat resistance obtained from the epoxy resin compositions. Background Technology

[0002] Epoxy resins have long been used in a wide range of industrial applications, but in recent years, the required performance levels have become increasingly demanding. In the electrical / electronic and power electronics fields, where electronic circuits are becoming increasingly dense and high-frequency, the increased heat generation from these circuits necessitates high heat dissipation properties in epoxy resin compositions used for insulation. Previously, heat dissipation was addressed using the thermal conductivity of fillers; however, with further advancements in integration, there is a need to improve the thermal conductivity of the epoxy resin itself, which serves as the matrix.

[0003] As epoxy resin compositions with excellent thermal conductivity, compositions using epoxy resins having mesogen structures are known. For example, Patent Document 1 discloses an epoxy resin composition with biphenol-type epoxy resin and polyphenol resin curing agent as essential components, and discloses its excellent stability and strength at high temperatures, making it suitable for use in a wide range of fields such as bonding, casting, sealing, molding, and lamination. Furthermore, Patent Document 2 discloses an epoxy compound having two mesogen structures linked by bent chains within the molecule. Moreover, Patent Document 3 discloses a resin composition comprising an epoxy compound having mesogens.

[0004] However, epoxy resins with this liquid crystal structure have high melting points. During mixing, the high-melting-point components are difficult to dissolve, resulting in melting residues and consequently reduced curability or heat resistance. Furthermore, uniform mixing of this epoxy resin with a hardener requires high temperatures, but under these conditions, the epoxy resin's curing reaction proceeds rapidly while the gelation time is shortened, severely limiting the mixing process and making it difficult to operate.

[0005] As a high thermal conductivity resin capable of melt mixing, Patent Document 4 discloses an epoxy resin obtained by epoxidizing a mixture of hydroquinone and 4,4'-dihydroxybiphenyl. However, it exhibits strong crystallinity but lacks solvent solubility, resulting in insufficient formability. Patent Document 5 discloses an epoxy resin obtained by epoxidizing a mixture of dihydroxydiphenylmethane and 4,4'-dihydroxybiphenyl. However, due to the presence of a large amount of difunctional epoxy resin derived from dihydroxydiphenylmethane, there are concerns about decreased productivity and operability caused by adhesion. Furthermore, its cured product suffers from a low thermal conductivity (Tg).

[0006] [Existing Technical Documents]

[0007] [Patent Literature]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 7-90052

[0009] [Patent Document 2] Japanese Patent Application Publication No. 9-118673

[0010] [Patent Document 3] Japanese Patent Application Publication No. 11-323162

[0011] [Patent Document 4] No. WO2009 / 110424

[0012] [Patent Document 5] Japanese Patent Application Publication No. 2010-43245 Summary of the Invention

[0013] [The problem the invention aims to solve]

[0014] Therefore, the object of the present invention is to solve the aforementioned problems and provide a crystalline epoxy resin with excellent reliability, which can be effectively used as an insulating material for electrical / electronic components such as semiconductor seals, laminates, and heat dissipation substrates, has excellent workability as a solid at room temperature and excellent low viscosity during molding, as well as epoxy resin compositions using the same, and a cured product with excellent thermal conductivity and heat resistance obtained from the epoxy resin composition.

[0015] [Technical means to solve the problem]

[0016] Various studies were conducted to address the aforementioned problems, and it was found that by setting the content of difunctional components in epoxy resin within a specific range, the proportion of difunctional components derived from dihydroxydiphenylmethane, which is a factor that exacerbates adhesion, can be reduced, thereby improving productivity and operability. Furthermore, by increasing the proportion of polyfunctional components, the crosslinking density and orientation are improved, resulting in excellent thermal conductivity and heat resistance, thus completing the present invention.

[0017] That is, the present invention is a crystalline epoxy resin, which is an epoxy resin represented by the following general formula (1), wherein the crystalline epoxy resin is characterized in that the total of the components n=0 and A being m=0 of general formula (a) and the components n=0 and A being A being general formula (b) is in the range of 40 area % to 85 area % as determined by gel permeation chromatography (GPC), and the presence proportion of the m=0 structure of general formula (a) in the structure of A in general formula (1) is 10 mol% or less.

[0018] [Chemistry 1]

[0019]

[0020] (In the formula, G represents glycidyl group, A represents the following general formula (a) or general formula (b), and n represents a number from 0 to 20.)

[0021] [Chemistry 2]

[0022]

[0023] (In the formula, G represents glycidyl group, and m represents a number from 0 to 10.)

[0024] [Chemistry 3]

[0025]

[0026] That is, the present invention is an epoxy resin obtained by reacting a mixture (hereinafter referred to as phenolic mixture) of 20 to 100 parts by weight of a phenolic compound represented by the following general formula (2) with epichlorohydrin relative to 100 parts by weight of 4,4'-dihydroxybiphenyl.

[0027] [Chemistry 4]

[0028]

[0029] (Where, m represents a number from 0 to 10.)

[0030] The present invention can be a crystalline epoxy resin having the following characteristics: in the phenol mixture, the content of the m=0 body of the phenolic compound represented by general formula (2) is 10 wt% or less, and the content of 4,4'-dihydroxydiphenylmethane is 5 wt% or less. In particular, in the phenolic compound represented by general formula (2), the content of the m=0 body can be 50 area% or less.

[0031] The crystalline epoxy resin of the present invention may be in the range of 140 g / eq. to 180 g / eq., be solid at room temperature, and have a melt viscosity of less than 20 mPa·s at 150°C.

[0032] In addition, the present invention is an epoxy resin composition, wherein the epoxy resin and the curing agent are essential components, and the present invention is an epoxy resin cured product, which is formed by curing the epoxy resin composition.

[0033] [The effects of the invention]

[0034] The crystalline epoxy resin and epoxy resin composition of the present invention have excellent workability and formability, and provide a cured material with excellent thermal conductivity and heat resistance. They can be suitable as insulating materials for electrical / electronic components such as semiconductor seals, laminates, and heat dissipation substrates, and exhibit excellent heat dissipation. Attached Figure Description

[0035] Figure 1 This is a graph showing the GPC chart of the epoxy resin obtained in Example 1.

[0036] Figure 2 This is a graph showing the GPC chart of the epoxy resin obtained in Example 2.

[0037] Figure 3 This is a graph showing the GPC chart of the epoxy resin obtained in Comparative Example 1. Detailed Implementation

[0038] The crystalline epoxy resin of the present invention is represented by general formula (1) and can be manufactured by reacting a mixture of 4,4'-dihydroxybiphenyl and a phenolic compound of general formula (2) with epichlorohydrin. This reaction can be carried out in the same manner as a conventional epoxidation reaction.

[0039] Regarding the obtained epoxy resin, in general formula (1), the total of the component with n=0 and A being m=0 in general formula (a) and the component with n=0 and A being general formula (b), as determined by GPC, is 40% to 85% area, preferably 45% to 80%, and more preferably 45% to 75%. If it is more than this, although the melt viscosity decreases, the strength of the resin decreases, and it is more prone to adhesion, thus deteriorating productivity and workability, and consequently, the heat resistance of the resulting cured product decreases. On the other hand, if it is less than this, although the heat resistance of the cured product increases, the melt viscosity increases, the formability deteriorates, and the thermal conductivity of the cured product decreases.

[0040] In the phenol mixture used as raw material, the mixing ratio of 4,4'-dihydroxybiphenyl to the phenolic compound of general formula (2) is in the range of 20 to 100 parts by weight relative to 100 parts by weight of 4,4'-dihydroxybiphenyl, preferably in the range of 30 to 80 parts by weight. If the ratio is less than this, the workability will deteriorate due to the high melting point of the epoxy compound of 4,4'-dihydroxybiphenyl; if the ratio is more than this, the heat resistance, thermal conductivity, and other properties of the cured product will decrease.

[0041] Regarding the phenolic compound of general formula (2), in general formula (2), m represents a number from 0 to 10, but its average value is preferably in the range of 0.5 to 5. More preferably, it is in the range of 0.8 to 4.5, and even more preferably, it is in the range of 1.0 to 4.0. In the phenolic compound represented by general formula (2), the proportion of the m=0 body is preferably 50 area % or less, more preferably 30 area % or less, and even more preferably 20 area % or less.

[0042] Furthermore, in the phenolic compound of general formula (2), the content of its m=0 body is 10% by weight or less, preferably 5% by weight or less, relative to the total amount of the phenol mixture. If the content is higher than this, the resin strength of the resulting epoxy resin decreases and the melting point increases, thus raising concerns about reduced productivity, operability, and formability when preparing epoxy resin compositions.

[0043] Furthermore, in the phenolic compounds of general formula (2), the m=0 body comprises 4,4'-dihydroxydiphenylmethane, 2,4'-dihydroxydiphenylmethane, and 2,2'-dihydroxydiphenylmethane as isomers. The content of 4,4'-dihydroxydiphenylmethane is 5 wt% or less, preferably 3 wt% or less, relative to the total amount of the phenolic mixture. If the content is higher than this, the resin strength of the resulting epoxy resin decreases and the melting point increases, thus raising concerns about decreased productivity, workability, and formability when preparing epoxy resin compositions.

[0044] The epoxy resin of the present invention is obtained by reacting a mixture of 4,4'-dihydroxybiphenyl and a phenolic compound of formula (2) (hereinafter referred to as the phenol mixture) with epichlorohydrin. An example of the reaction with epichlorohydrin is as follows: the phenol mixture is dissolved in epichlorohydrin in excess relative to its phenolic hydroxyl groups in a molar ratio, and then the reaction is carried out in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide at a temperature of 50°C to 150°C, preferably 60°C to 100°C, for 1 hour to 10 hours. The amount of alkali metal hydroxide used is in the range of 0.9 mol to 1.3 mol, preferably 1.0 mol to 1.2 mol, relative to 1 mol of the hydroxyl groups in the phenol mixture. Epichlorohydrin is used in excess relative to the hydroxyl groups in the phenol mixture, typically from 2 mol to 15 mol, preferably from 3 mol to 10 mol, relative to 1 mol of the hydroxyl groups in the phenol mixture. After the reaction is complete, excess epichlorohydrin is removed by distillation, and the residue is dissolved in solvents such as toluene and methyl isobutyl ketone. The residue is then filtered and washed with water to remove inorganic salts. The solvent is then removed by distillation, thereby obtaining the target epoxy resin.

[0045] When manufacturing the epoxy resin of the present invention, a small amount of other types of phenolic compounds, other than 4,4'-dihydroxybiphenyl and phenolic compounds of general formula (2), may be mixed into the phenol mixture. However, in this case, the total amount of other types of phenolic compounds is preferably 50 wt% or less, preferably 30 wt% or less, and more preferably 10 wt% or less of all phenolic compounds.

[0046] The epoxy equivalent of the crystalline epoxy resin of the present invention is preferably in the range of 120 g / eq. to 200 g / eq., and more preferably in the range of 140 g / eq. to 180 g / eq. from the viewpoint of suppressing adhesion and improving flowability.

[0047] The crystalline epoxy resin of the present invention is crystalline at room temperature. The presence of crystallinity can be confirmed by differential scanning calorimetry (DSC) using the endothermic peak value of melting accompanying crystallization. Furthermore, regarding the endothermic peak value, since the crystalline epoxy resin of the present invention is a mixture, multiple peak values, or broad peak values, are sometimes observed. As for the melting point observed by DSC, among the endothermic peak values ​​of epoxy resins derived from 4,4'-dihydroxybiphenyl and phenolic compounds of general formula (2), the lowest temperature endothermic peak value is 120°C or higher, preferably 130°C or higher, and the highest temperature endothermic peak value is 160°C or lower, preferably 150°C or lower. If it is lower than this, the thermal conductivity of the cured material deteriorates. Conversely, if it is higher than this, problems such as decreased solubility with the curing agent and decreased formability of the composition exist. Furthermore, the lower the melt viscosity at 150°C, the better; preferably 50 mPa·s or lower, and more preferably 20 mPa·s or lower.

[0048] Regarding the purity of the epoxy resin of the present invention, especially the hydrolyzable chlorine content, it is preferable to have a low purity from the viewpoint of improving the reliability of the applicable electronic components. While not particularly limited, it is preferably 1000 ppm or less, and more preferably 500 ppm or less. Furthermore, the hydrolyzable chlorine content referred to in the present invention is a value determined by the following method: 2 g of the sample is dissolved in 30 ml of dioxane, 25 ml of 0.1 N-KOH is added, the mixture is reacted in a hot water bath at 70°C for 30 minutes, then cooled to room temperature, and 100 ml of 80% acetone water is added. The mixture is then potentiometrically titrated with a 0.002 N-AgNO3 aqueous solution.

[0049] Ideally, the epoxy resin composition of the present invention comprises at least 50 wt% of the crystalline epoxy resin as the epoxy resin component. Preferably, it comprises at least 70 wt% of the epoxy resin component, and more preferably at least 80 wt%. If the proportion used is less than this, the effect on improving the thermal conductivity, heat resistance, etc., when the cured product is formed is small.

[0050] In the epoxy resin compositions of the present invention, in addition to the crystalline epoxy resins used as essential components of the present invention, other conventional epoxy resins having two or more epoxy groups in their molecules may also be used. Examples include bisphenol A, 3,3',5,5'-tetramethyl-4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ketone, fluorenebisphenol, 4,4'-biphenyl, 3,3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl, 2,2'-biphenyl, resorcinol, catechol, and tert-butyl. Hydroquinone, hydroquinone, tert-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-dihydroxynaphthalene, and the aforementioned dihydroxynaphthalene Allylated or polyallylated naphthyl compounds, allylated bisphenol A, allylated bisphenol F, allylated phenolic varnishes, and other diphenols; or phenolic varnishes, bisphenol A varnishes, o-cresol varnishes, m-cresol varnishes, p-cresol varnishes, xylenol varnishes, poly(p-hydroxystyrene), tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetra(4-hydroxyphenyl)ethane. These epoxy resins include ternary or higher phenols such as phloroglucinol, pyrogallol, tert-butylpyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2,4-phenylpyrogallol, 2,3,4-trihydroxybenzophenone, phenolic aralkyl resins, naphthol aralkyl resins, and dicyclopentadiene resins; or glycidyl ethers derived from halogenated bisphenols such as tetrabromobisphenol A. One or a mixture of two or more of these epoxy resins can be used.

[0051] As a curing agent used in the epoxy resin composition of the present invention, any substance known as an epoxy resin curing agent can generally be used, but a phenolic curing agent is preferred. Phenolic curing agents include phenolic compounds, which, in addition to phenolic compounds as a single compound, also contain phenolic resins.

[0052] Specific examples of phenolic curing agents include: bisphenol A, bisphenol F, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, 1,4-bis(4-hydroxyphenoxy)benzene, 1,3-bis(4-hydroxyphenoxy)benzene, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, phenolic varnish, bisphenol A phenolic varnish, o-cresol phenolic varnish, m-cresol phenolic varnish, p-cresol phenolic varnish, xylenol phenolic varnish, poly(p-hydroxystyrene), hydroquinone, resorcinol, and catechol. Tert-butylcatechol, tert-butylhydroquinone, phloroglucinol, phloroglucinol, tert-butylcatechol, allylated phloroglucinol, polyallylated phloroglucinol, 1,2,4-phenylpyroglucinol, 2,3,4-trihydroxybenzophenone, 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-dihydroxynaphthalene, allylated or polyallylated dihydroxynaphthalenes, allylated bisphenol A, allylated bisphenol F, allylated phenolic varnish, allylated phloroglucinol, etc. In addition, two or more hardeners can be mixed for use.

[0053] In addition to the phenolic curing agents described above, other curing agents generally known as curing agents can be used as curing agents in the epoxy resin compositions of the present invention. Examples include amine curing agents, acid anhydride curing agents, phenolic curing agents, polythiol curing agents, polyaminoamide curing agents, isocyanate curing agents, and blocked isocyanate curing agents. The amount of these curing agents can be appropriately set considering the type of curing agent to be formulated and the physical properties of the resulting thermally conductive epoxy resin molded article.

[0054] Specific examples of amine-based curing agents include: aliphatic amines, polyether polyamines, alicyclic amines, and aromatic amines. Examples of aliphatic amines include: ethylenediamine, 1,3-diaminopropane, 1,4-diaminopropane, hexamethylenediamine, 2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, iminodipropylamine, bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-hydroxyethylethylenediamine, tetra(hydroxyethyl)ethylenediamine, etc. Examples of polyether polyamines include: triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis(propylamine), polyoxypropylene diamine, and polyoxypropylene triamines, etc. Examples of alicyclic amines include: isophorone diamine, N-aminoethylpiperazine, bis(4-amino-3-methyldicyclohexyl)methane, bis(aminomethyl)cyclohexane, 3,9-bis(3-aminopropyl)2,4,8,10-tetraoxaspirocyclo(5,5)undecane, norbornene diamine, etc. 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'-diamino-1,2-diphenylethane, 2,4-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, m-aminophenol, m-aminobenzylamine, benzyl dimethylamine, 2-(dimethylaminomethyl)phenol, triethanolamine, methylbenzylamine, α-(m-aminophenyl)ethylamine, α-(p-aminophenyl)ethylamine, diaminodiethyldimethyldiphenylmethane, α,α'-bis(4-aminophenyl)-p-diisopropylbenzene, etc.

[0055] Specific examples of anhydride-based curing agents include: dodecenyl succinic anhydride, polyadipic anhydride, polyazelic anhydride, polydecanic anhydride, poly(ethyl octadecanoic acid) anhydride, poly(phenyl hexadecanoic acid) anhydride, methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic anhydride, hexahydrophthalic anhydride, methyl bicycloheptenyl dicarboxylic anhydride, tetrahydrophthalic anhydride, trialkyl tetrahydrophthalic anhydride, methyl cyclohexene dicarboxylic anhydride, methyl cyclohexene tetracarboxylic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic tetracarboxylic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol dipreptyltricarboxylate, HET anhydride, and nadic anhydride. (Anhydride), methylnadic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthous succinic anhydride, 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthous succinic anhydride, etc.

[0056] Regarding the mixing ratio of epoxy resin and hardener, it is preferably in the range of 0.8 to 1.5 equivalence ratio of epoxy groups to functional groups in the hardener. If it is outside this range, unreacted epoxy groups or functional groups in the hardener will remain after curing, which will reduce the reliability of the sealing function and is therefore not preferred.

[0057] In addition, oligomers or polymers such as polyester, polyamide, polyimide, polyether, polyurethane, petroleum resin, indene resin, indene-benzofuran resin, and phenoxy resin may be appropriately incorporated into the epoxy resin composition of the present invention as other modifiers. Regarding the amount added, it is generally in the range of 1 to 30 parts by weight relative to 100 parts by weight of the total resin components.

[0058] Furthermore, the epoxy resin composition of the present invention may be formulated with additives such as inorganic fillers, pigments, flame retardants, reversibility enhancers, coupling agents, and flow improvers. Examples of inorganic fillers include spherical or fragmented fused silica, crystalline silica powder, alumina powder, glass powder, or mica, talc, calcium carbonate, alumina, hydrated alumina, etc., and when used in semiconductor sealing materials, the preferred formulation amount is 70% by weight or more, and more preferably 80% by weight or more.

[0059] As pigments, there are organic or inorganic extender pigments, flake pigments, etc. As viscotropic agents, examples include: silicon-based, castor oil-based, aliphatic amide wax, oxidized polyethylene wax, organobentonite-based, etc.

[0060] Furthermore, curing accelerators may be used in the epoxy resin composition of the present invention as needed. Examples include amines, imidazoles, organophosphorus compounds, Lewis acids, etc., specifically including: 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; organophosphorus compounds such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine; tetrasubstituted phosphine-tetrasubstituted borates such as tetraphenylphosphine-tetraphenylborate, tetraphenylphosphine-ethyltriphenylborate, and tetrabutylphosphine-tetrabutylborate; and tetraphenylborates such as 2-ethyl-4-methylimidazole-tetraphenylborate and N-methylmorpholine-tetraphenylborate. As an addition amount, it is typically in the range of 0.01 parts by weight to 5 parts by weight relative to 100 parts by weight of the total resin components.

[0061] Furthermore, as needed, 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-reducing agents such as silicone oil, and lubricants such as calcium stearate may be used in the epoxy resin composition of the present invention.

[0062] The epoxy resin composition of the present invention can be dissolved in an organic solvent to form a varnish state, then impregnated in fibrous materials such as glass cloth, polyaramid nonwoven fabric, liquid crystal polymer, or polyester nonwoven fabric, followed by solvent removal to form a prepreg. Alternatively, depending on the circumstances, it can be coated onto sheets such as copper foil, stainless steel foil, polyimide film, or polyester film to form a laminate.

[0063] If the epoxy resin composition of the present invention is heated and cured, the cured resin product of the present invention can be prepared. The cured product can be obtained by molding the epoxy resin composition using methods such as casting, compression molding, or transfer molding. The temperature at this time is typically in the range of 120°C to 220°C.

[0064] [Example]

[0065] The present invention will be specifically described below with reference to synthetic examples, embodiments, and comparative examples. However, the present invention is not limited to these. Furthermore, regarding the measurement method, the following methods are used for measurement.

[0066] 1) Epoxy equivalent

[0067] A potentiometric titration apparatus was used, with chloroform as the solvent, and tetraethylammonium bromide acetic acid solution was added. The determination was performed using a 0.1 mol / L perchloric acid-acetic acid solution via potentiometric titration.

[0068] 2) Melting point

[0069] The differential scanning calorimetry (DSC) peak temperature was determined using a differential scanning calorimetry (DSC) device (EXSTAR 6000DSC / 6200 manufactured by SII NanoTechnology) at a heating rate of 5°C / min. This DSC peak temperature was then used as the melting point of the epoxy resin.

[0070] 3) Melt viscosity

[0071] The measurements were performed at 150°C using a CAP2000H rotational viscometer manufactured by Brookfield.

[0072] 4) GPC measurement

[0073] Apparatus used: HLC-8320 (manufactured by Tosoh Corporation) and columns: 2 x TSKgel SuperHZ2500 and 2 x TSKgel SuperHZ2000 (both manufactured by Tosoh Corporation). The conditions were: solvent: tetrahydrofuran, flow rate: 0.35 ml / min, temperature: 40 °C, detector: refractive index (RI).

[0074] 5) Adhesion test

[0075] The experiment was conducted using samples divided into 1.7 mm to 5.0 mm pieces using a sieve. 10 g of each sample was measured in a metal container placed in a constant-temperature bath at 0°C, 5°C, and 10°C. The sample was then left to stand in the bath for 10 minutes while being pressed down with a metal rod (370 g) of the same diameter. The presence or absence of adhesion was then evaluated. A resin coagulation content of less than 30 wt% was designated as ○, 30 wt% to 60 wt% as △, and more than 60 wt% as ×.

[0076] 6) Hardness

[0077] Press the measuring part of the hardness tester (TECLOCK, GS-701N) onto the smooth surface of the solidified sample, and measure the hardness after 2 minutes.

[0078] 7) Glass transition point (Tg)

[0079] Tg was determined using a thermomechanical measuring apparatus (EXSTAR 6000TMA / 6100 manufactured by SII NanoTechnology) at a heating rate of 10 °C / min.

[0080] 8) Thermal conductivity

[0081] Thermal conductivity was measured using a NETZSCH LFA447 thermal conductivity meter via the transient hotwire method.

[0082] Furthermore, in the examples, BPF used bisphenol F with a GPC determination of 97 area % of m=0 (hydroxyl equivalent: 100 g / eq., average m value of 0.04), PN-A used phenolic resin with a GPC determination of 11 area % of m=0 (hydroxyl equivalent: 105 g / eq., average m value of 1.33), and PN-B used phenolic resin with a GPC determination of 56 area % of m=0 (hydroxyl equivalent: 104 g / eq., average m value of 0.66).

[0083] Regarding the isomer structure ratios in the m=0 variant, in BPF it is 36 mol% for the 4,4'- variant, 47 mol% for the 2,4'- variant, and 17 mol% for the 2,2'- variant; in PN-A it is 59 mol% for the 4,4'- variant, 35 mol% for the 2,4'- variant, and 6 mol% for the 2,2'- variant; and in PN-B it is 36 mol% for the 4,4'- variant, 39 mol% for the 2,4'- variant, and 25 mol% for the 2,2'- variant.

[0084] Example 1

[0085] In a 1000L separable flask, 50.0g of 4,4'-dihydroxybiphenyl and 22.6g of PN-A were dissolved in 348g of epichlorohydrin and 52g of diethylene glycol dimethyl ether. Under reduced pressure (approximately 180 Torr), 68.1g of a 48% sodium hydroxide aqueous solution was added dropwise over 3 hours at 70°C. During this process, the generated water was removed from the system by azeotropic reaction with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the addition was complete, the reaction continued for another hour to dehydrate the product. Epichlorohydrin was then removed by distillation, and 432g of toluene was added, followed by washing with water to remove salt. Water was then removed by separation, and toluene was removed by reduced pressure distillation to obtain 95g of a white crystalline epoxy resin (epoxy resin A). The epoxy equivalent was 157g / eq, the hydrolytic chlorine content was 27ppm, and the viscosity at 150°C was 8mPa·s. The total proportion of the difunctional epoxy resin component determined by GPC was 67.8% of the area.

[0086] Example 2

[0087] In a 1000L separable flask, 50.0g of 4,4'-dihydroxybiphenyl and 28.2g of PN-A were dissolved in 373g of epichlorohydrin and 56g of diethylene glycol dimethyl ether. 73.0g of a 48% sodium hydroxide aqueous solution was added dropwise over 3 hours at 70°C under reduced pressure (approximately 180 Torr). During this process, the generated water was removed from the system by azeotropic reaction with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the addition was complete, the reaction continued for another hour to remove water. Epichlorohydrin was then removed by distillation, and 464g of toluene was added, followed by washing with water to remove salt. Water was then removed by separation, and toluene was removed by reduced pressure distillation to obtain 101g of a white crystalline epoxy resin (epoxy resin B). The epoxy equivalent was 158g / eq., the hydrolytic chlorine content was 28ppm, and the viscosity at 150°C was 10mPa·s. The total proportion of the difunctional epoxy resin component determined by GPC was 64.4% of the area.

[0088] Comparative Example 1

[0089] In a 1000L separable flask, 50.0g of 4,4'-dihydroxybiphenyl and 26.9g of BPF were dissolved in 373g of epichlorohydrin and 34g of diethylene glycol dimethyl ether. 73.0g of a 48% sodium hydroxide aqueous solution was added dropwise over 3 hours at 70°C under reduced pressure (approximately 180 Torr). During this process, the generated water was removed from the system by azeotropic reaction with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the addition was complete, the reaction continued for another hour to remove water. Epichlorohydrin was then removed by distillation, and 462g of toluene was added, followed by washing with water to remove salt. Water was then removed by separation, and toluene was removed by reduced pressure distillation to obtain 92g of a white crystalline epoxy resin (epoxy resin C). The epoxy equivalent was 160g / eq., the hydrolytic chlorine content was 90ppm, and the viscosity at 150°C was 7mPa·s. The total proportion of the difunctional epoxy resin component determined by GPC was 87.0% of the area.

[0090] Comparative Example 2

[0091] In a 3000L separable flask, 150.0g of 4,4'-dihydroxybiphenyl and 50g of PN-B were dissolved in 1160g of epichlorohydrin and 116g of diethylene glycol dimethyl ether. Under reduced pressure (approximately 130 Torr), 193.0g of a 48% sodium hydroxide aqueous solution was added dropwise over 3 hours at 60°C. During this process, the generated water was removed from the system by azeotropic reaction with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the addition was complete, the reaction continued for another hour to dehydrate the product. Epichlorohydrin was then removed by distillation, and 1200g of methyl isobutyl ketone was added, followed by washing with water to remove salt. Subsequently, 25.0g of 20% sodium hydroxide was added at 85°C, and the mixture was stirred for 1 hour, followed by washing with 1000mL of warm water. After separating the water, the methyl isobutyl ketone was removed by reduced pressure distillation to obtain 288g of a white crystalline epoxy resin (epoxy resin D). The epoxy equivalent is 164 g / eq., the hydrolyzable chlorine content is 64 ppm, and the viscosity at 150°C is 7 mPa·s. The total proportion of the difunctional epoxy resin component, determined by GPC, is 85.6% (area).

[0092] Figure 1 This is a graph showing the GPC chart of the epoxy resin obtained in Example 1. Figure 2 This is a graph showing the GPC chart of the epoxy resin obtained in Example 2. Figure 3 This is a graph showing the GPC chart of the epoxy resin obtained in Comparative Example 1.

[0093] Table 1 shows the various qualities of epoxy resins A to D obtained in Examples 1 to 2 and Comparative Examples 1 to 2.

[0094] [Table 1]

[0095]

[0096] Examples 3-4 and Comparative Examples 3-4

[0097] As the epoxy resin component, epoxy resin A or epoxy resin B obtained in Examples 1-2, and epoxy resin C or epoxy resin D obtained in Comparative Examples 1-2 were used as the curing agent. Phenolic varnish resin (BRG-555, manufactured by Chung-Ei Chemical Industry Co., Ltd., with a hydroxyl equivalent of 105 g / eq. and a softening point of 68°C) was used as the curing accelerator. Triphenylphosphine (TPP, manufactured by Shikoku Chemical Co., Ltd.) was used as the curing accelerator. The epoxy resin compositions were obtained according to the formulations shown in Table 2. The values ​​in the table represent parts by weight in the formulation.

[0098] The epoxy resin composition was molded at 175°C and post-cured at 180°C for 3 hours to obtain a hardened test piece, which was then used for various physical property tests.

[0099] [Table 2]

[0100] Example 3 Example 4 Comparative Example 3 Comparative Example 4 Epoxy Resin A 30.2 Epoxy Resin B 30.1 Epoxy Resin C 30.2 Epoxy Resin D 30.5 hardener 19.8 19.9 19.8 19.5 hardening accelerator 0.03 0.03 0.03 0.03 Tg (°C) 149 147 131 136 Thermal conductivity (W / m·K) 0.24 0.23 0.22 0.22

[0101] As can be seen from these results, the epoxy resin obtained by the examples has good workability in solid form, and the cured products obtained using it have excellent thermal conductivity and heat resistance.

Claims

1. A crystalline epoxy resin, characterized in that, It is an epoxy resin represented by the following general formula (1), wherein the total of the components with n=0 and A being m=0 in general formula (a) and the components with n=0 and A being general formula (b), as determined by gel permeation chromatography, is in the range of 45 area% to 75 area%; and in the structure of A in general formula (1), the proportion of the structure with m=0 in general formula (a) is 10 mol% or less. In the formula, G represents glycidyl group, A represents the following general formula (a) or general formula (b), and n represents a number from 0 to 20; In the formula, G represents glycidyl group, and m represents a number from 0 to 10; 2. The crystalline epoxy resin according to claim 1 is an epoxy resin obtained by reacting a phenol mixture with epichlorohydrin, wherein the phenol mixture is a mixture of 20 to 100 parts by weight of a phenolic compound represented by the following general formula (2) mixed with 100 parts by weight of 4,4'-dihydroxybiphenyl, wherein the content of the m=0 form of the phenolic compound represented by general formula (2) in the phenol mixture is 10 wt% or less, and the content of 4,4'-dihydroxydiphenylmethane is 5 wt% or less. in, m represents a number from 0 to 10.

3. The crystalline epoxy resin according to claim 1 or 2, wherein, In the phenolic compounds represented by general formula (2), the content of m=0 bodies is less than 50% by area.

4. The crystalline epoxy resin according to claim 1, wherein, The epoxy equivalent ranges from 140 g / eq. to 180 g / eq., and it is a solid at room temperature with a melt viscosity of less than 20 mPa·s at 150°C.

5. An epoxy resin composition, characterized in that, The crystalline epoxy resin and the hardener as described in any one of claims 1 to 4 are essential components.

6. An epoxy resin cured product, characterized in that, It is formed by curing the epoxy resin composition as described in claim 5.

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