Polyvalent hydroxy resin, epoxy resin, resin composition, and cured product thereof

Abstract

To provide: a compound excellent in solvent solubility and also excellent in heat resistance, thermal decomposition stability, thermal conductivity, and flame retardancy; and a curable resin composition containing this compound.SOLUTION: Provided is a polyfunctional epoxy compound represented by the general formula (1) in the figure. In the formula (1), each of R1 to R6 independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, each X independently represents a biphenyl derivative structure, a benzonitrile structure, a diphenylsulfonyl structure, a xylylene structure, or a -(CH2)m- structure, m represents a number from 3 to 10, and n represents a number from 1 to 15.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyhydric hydroxy resin, an epoxy resin, an epoxy resin composition, and a cured product thereof, and more particularly to an epoxy resin composition useful as an insulating material for electric and electronic parts such as semiconductor encapsulation, laminates, and heat dissipation substrates.

Background Art

[0002] Printed circuit boards, encapsulants, potting materials, etc. used in communication equipment are being actively studied for high-speed communication technologies to improve signal transmission speed with the increase in communication speed and communication volume. In the application of printed circuit boards, a curable resin that enables multi-layer formation is required.

[0003] On the other hand, heat generation from electronic arithmetic components that process such a large amount of information is significant, and problems such as a decrease in the processing speed of electronic arithmetic components occur due to heat accumulation. Therefore, in printed circuit boards, as a technique for appropriately cooling with a heat sink or the like, methods such as incorporating heat transfer members such as copper coins and copper inlays (Patent Document 1), and making the shape of the filler to be blended special (Patent Document 2) are known. However, such methods lead to an increase in weight and a larger size of the device, which is not preferable.

[0004] In addition, in the encapsulant composition, as a method for increasing the thermal conductivity, a method of removing heat from electronic arithmetic components by examining the types and amounts of various fillers has been adopted. For example, attempts have been made to contain inorganic fillers such as crystalline silica, silicon nitride, aluminum nitride, and spherical alumina powder having a high thermal conductivity (Patent Documents 3 and 4). However, when the content rate of the inorganic filler is increased, the fluidity decreases along with an increase in viscosity during molding, and a problem occurs that the moldability is impaired. Therefore, there is a limit to simply increasing the content rate of the inorganic filler.

[0005] From the above background, methods of improving the thermal conductivity of the composition by increasing the thermal conductivity of the matrix resin itself have also been studied. For example, liquid crystalline epoxy resins having a rigid mesogenic group and epoxy resin compositions using the same have been proposed (Patent Documents 5 and 6). However, as the curing agent used in these epoxy resin compositions, an aromatic diamine compound is used, and there is a limit to increasing the filling rate of the inorganic filler, and there are also problems in terms of electrical insulation. Further, when an aromatic diamine compound is used, although the liquid crystallinity of the cured product can be confirmed, the crystallinity of the cured product is low, and it is not sufficient in terms of high thermal conductivity, low thermal expansion, low moisture absorption, etc. Furthermore, in order to exhibit liquid crystallinity, it is necessary to apply a strong magnetic field to orient the molecules, and there are large equipment constraints for wide industrial use. Also, in the blending system with the inorganic filler, the thermal conductivity of the inorganic filler is overwhelmingly larger than that of the matrix resin, and even if the thermal conductivity of the matrix resin itself is increased, it does not significantly contribute to the improvement of the thermal conductivity of the composite material, and a sufficient thermal conductivity improvement effect has not been obtained.

[0006] Patent Document 7 proposes reducing crystallinity by removing the crystalline component of an epoxy resin having a biphenyl-biphenyl aralkyl structure, but the solvent solubility is insufficient, and there are problems in practicality. Also, when mixing another epoxy resin to improve moldability and solvent solubility, while the melting point of the resin decreases and it becomes easier to mix uniformly, it becomes difficult to maintain the heat resistance, thermal decomposition stability, mechanical strength, and thermal conductivity, which are the physical properties of the cured product. Patent Document 8 proposes a resin composition using a biphenyl aralkyl type epoxy resin and a bisphenol methane type epoxy resin in combination, but due to strong crystallinity, melt kneading is difficult, and the solvent solubility is also insufficient for practical use in laminate applications.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

[0008] 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 has good melt kneadability at 100°C or lower, excellent solvent solubility, and gives a cured product excellent in 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 polyhydric hydroxy resin suitable as an intermediate of this epoxy resin. [Means for Solving the Problems]

[0009] 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 in heat resistance, thermal decomposition stability, thermal conductivity, and flame retardancy.

[0010] That is, the present invention is an epoxy resin represented by the following general formula (1). [Chemical Formula] In formula (1), R1 to R6 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and X independently represents a structure represented by formula (2), a benzonitrile structure, a diphenylsulfonyl structure, a xylylene structure, or -(CH2) m -, where m represents a number from 3 to 10 and n represents a number from 1 to 15.

Chemical formula

[0011] X of the above epoxy resin preferably has the structure represented by formula (2).

[0012] Furthermore, the present invention is a polyhydroxy resin represented by the following general formula (3).

Chemical formula

[0013] X of the above polyhydroxy resin preferably has the structure represented by formula (2).

[0014] The present invention is also an epoxy resin composition characterized by containing the above epoxy resin or polyhydroxy resin curing agent as an essential component. Furthermore, the present invention is a resin cured product characterized by curing this resin cured product.

Advantages of the Invention

[0015] 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 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

[0016]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0017] Hereinafter, the present invention will be described in detail.

[0018] The present invention is an epoxy resin represented by the following general formula (1).

Chemical formula

Chemical formula

[0019] R1 to R6 are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms. As the monovalent hydrocarbon group having 1 to 6 carbon atoms, an alkyl group is preferable from the viewpoint of solvent solubility, and an aromatic group is preferable from the viewpoints of heat resistance and high thermal conductivity. An alkyl group having more than 6 carbon atoms makes it difficult to suppress molecular motion, and there is also a concern about a decrease in compatibility. In addition, a bulky structure with a large steric hindrance has a concern about solvent solubility due to an increase in crystallinity. A more preferable structure is more preferably a hydrogen atom, a methyl group or a phenyl group. R1 to R6 may be a mixture of different structures.

[0020] n is the number of repetitions and represents a number from 1 to 15. Preferably, it is a mixture of components with different n values. As the n value (average value), 1.0 to 5.0 is preferred, and more preferably 1.5 to 3.5. In the epoxy resin of the present invention, although the case of only the n = 0 compound is excluded, it may be a mixture with the n = 0 compound. However, in terms of the area percentage measured by gel permeation chromatography (GPC area %), those with n = 0 are preferably 50% or less.

[0021] X independently represents a structure shown in formula (2), a benzonitrile structure, a diphenylsulfonyl structure, a xylylene structure, or -(CH2) m -. Regarding the alkyl structure represented by -(CH2)m-, m is the number of repetitions and represents a number from 3 to 10. More preferably, it is a number from 4 to 8. If it is less than 3, the flexibility is low and the tendency of the relaxation effect of crystallinity is low. If it is greater than 10, the thermal conductivity and heat resistance of the cured product tend to decrease significantly. As described as "independently", the epoxy resin of formula (1) of the present invention can be a mixture in which each X has a different structure, and it is possible to adjust the high thermal conductivity, moldability, and solvent solubility. When X is the structure shown in formula (2), the thermal conductivity of the cured product tends to improve.

[0022] As a preferred structure, specifically, it can be exemplified by the epoxy resin of the following formula (4) in which X is a biphenyl-containing structure shown in formula (2).

Chemical formula

[0023] The preferred range of the epoxy equivalent of the epoxy resin of the present invention is 150 to 450 g / eq, and the more preferred range is 200 to 350 g / eq. If it is smaller than this range, reaction control becomes difficult because it reacts rapidly, and if 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 number average molecular weight Mn is preferably from 500 to 2,000, more preferably from 500 to 1,000. The softening point is preferably from 60 to 100 °C, more preferably from 70 to 90 °C.

[0024] The epoxy resin of the present invention can be obtained by reacting a polyhydroxy compound (resin) represented by the formula (3) with epichlorohydrin. R1 to R6, n, and X are the same as those of the epoxy resin of the formula (1).

Chemical formula

[0025] The polyfunctional hydroxy compound of the formula (3) preferably has a hydroxyl equivalent of 100 to 350 g / eq, more preferably 120 to 250 g / eq. The number average molecular weight Mn is preferably from 500 to 1,500. The polyfunctional hydroxy compound (phenolic compound) represented by the formula (3) is not limited in production method as long as it has a predetermined structure, but can be preferably obtained by reacting a trifunctional trihydroxy compound with a dihalogen compound having an X group in the presence of a basic catalyst. In this case, examples of the trifunctional trihydroxy compound include 4,4’,4”-trihydroxytriphenylmethane, and 4,4’,4”-trihydroxytriphenylmethane may have one or more hydrocarbon groups such as a methyl group or a phenyl group as substituents. Examples of the dihalogen compound having an X group include dihalogen nitrile compounds such as 2,4-dichlorobenzonitrile, 2,5-dichlorobenzonitrile, 2,6-dichlorobenzonitrile, 3,5-dichlorobenzonitrile, 2,4-dibromobenzonitrile, 2,5-dibromobenzonitrile, 2,6-dibromobenzonitrile, 3,5-dibromobenzonitrile; dihalogen alkyl compounds such as 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane, 1,6-dibromohexane; 4,4'-dibromodiphenyl sulfone, 4,4'-dichlorodiphenyl sulfone, 4,4'-bishydroxymethylbiphenyl, 4,4'-bischloromethylbiphenyl, 4,4'-bisbromomethylbiphenyl, 4,4'-bis-methoxymethylbiphenyl, 4,4'-bisethoxymethylbiphenyl, p-xylene dichloride and the like. As the crosslinked structure contributing to high thermal conductivity, a biphenyl structure is suitable, and 4,4'-bischloromethylbiphenyl is particularly suitable as a crosslinking agent from the viewpoint of reactivity.

[0026] When reacting phenols with an aromatic condensing agent, the molar ratio is generally in the range of 0.2 to 0.7 mol, more preferably 0.4 to 0.7 mol, of the aromatic condensing agent per 1 mol of phenols. If it is less than 0.2 mol, the ratio of the n = 0 form of the polyhydric hydroxy resin obtained will be high, and there is a concern about a decrease in solubility such as showing crystallinity. On the other hand, if it is more than 0.7 mol, the amount of high molecular weight components will increase, making it difficult to produce stably.

[0027] The reaction between phenols and aromatic condensers can be carried out without a catalyst or in the presence of an acid catalyst such as an inorganic acid or an organic acid. When using 4,4'-bis(chloromethyl)biphenyl, the reaction can be carried out without a catalyst. Generally, in order to suppress side reactions such as the reaction between the chloromethyl group and the hydroxyl group to form an ether bond, it is preferable to carry out the reaction in the presence of an acidic catalyst. As this acidic catalyst, it can be appropriately selected from well-known inorganic acids 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, methanesulfonic acid, trifluoromethanesulfonic acid, Lewis acids such as zinc chloride, aluminum chloride, iron chloride, boron trifluoride, or solid acids, etc. can be mentioned.

[0028] Usually, this reaction is carried out at 100 to 250 °C for 1 to 20 hours. Preferably, it is carried out at 100 to 180 °C, more preferably at 140 to 180 °C. If the reaction temperature is low, the reactivity is poor and it takes time. If the reaction temperature is high, there is a risk of resin decomposition.

[0029] As a solvent during the reaction, for example, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, diethylene glycol dimethyl ether, triglyme, and aromatic compounds such as benzene, toluene, chlorobenzene, dichlorobenzene, etc. can be used well. Among these, ethyl cellosolve, diethylene glycol dimethyl ether, triglyme, etc. are particularly preferred. After the reaction is completed, the obtained polyhydroxy resin may remove the solvent by methods such as distillation under reduced pressure, washing with water, or reprecipitation in a poor solvent, but it may also be used as a raw material for the epoxidation reaction while leaving the solvent.

[0030] The polyhydroxy resin thus obtained can be used not only as a raw material for epoxy resins but also as an epoxy resin curing agent. Further, by combining with a curing agent such as hexamine, it can also be applied as a phenolic resin molding material.

[0031] The trifunctional trihydroxy compound can be obtained by polycondensation of a phenolic compound and an aromatic aldehyde. The reaction 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. 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 in terms of excellent activity. The acid catalyst may be added before the reaction or during the reaction.

[0032] When polycondensing a phenolic compound and an aromatic aldehyde to obtain a trifunctional trihydroxy compound, the reaction temperature is in the range of 20 to 140 °C, preferably in the range of 80 to 110 °C.

[0033] The charge ratio of the phenolic compound / aromatic aldehyde when polycondensing a phenolic compound and an aromatic aldehyde to obtain a trifunctional trihydroxy compound is in the range of 1 / 0.1 to 1 / 0.5 in terms of molar ratio because the phenolic compound after the reaction can be easily removed by reprecipitation or the like. More preferably, it is in the range of 1 / 0.3 to 1 / 0.5.

[0034] The method for producing the epoxy resin of the present invention by the reaction of the polyhydroxy resin represented by the above formula (3) and epichlorohydrin will be described. This reaction can be carried out in the same manner as the well-known epoxidation reaction.

[0035] For example, after dissolving the above polyhydroxy resin in excess epichlorohydrin, it is reacted at 50 to 150°C, preferably 60 to 120°C for 1 to 10 hours in the presence of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. The amount of epichlorohydrin used at this time is in the range of 0.8 to 2 moles, preferably 0.9 to 1.2 moles, per mole of hydroxyl group in the polyhydroxy resin. After completion of the reaction, the excess epichlorohydrin is distilled off, 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 distilled off to obtain the target epoxy resin represented by the general formula (1). When performing the epoxidation reaction, a catalyst such as a quaternary ammonium salt may be used.

[0036] The purity of the epoxy resin of the present invention, particularly the amount of hydrolyzable chlorine, is preferably less from the viewpoint of improving the reliability of the electronic components to be applied. Although not particularly limited, it is preferably 1000 ppm or less, more preferably 500 ppm or less. The hydrolyzable chlorine referred to in the present invention means a value measured by the following method. That is, after dissolving 0.5 g of the sample in 30 ml of dioxane, 10 ml of 1N-KOH is added and boiled under reflux for 30 minutes, then cooled to room temperature, and further 100 ml of 80% acetone water is added, and the value obtained by potentiometric titration with a 0.002N-AgNO3 aqueous solution.

[0037] The epoxy resin composition of the present invention contains an epoxy resin and a curing agent, and contains the epoxy resin of the general formula (1) as an epoxy resin component.

[0038] In addition to the epoxy resin of the general formula (1) used as an essential component in the epoxy resin composition of the present invention, ordinary other epoxy resins having two or more epoxy groups in the molecule may be used in combination. For example, bisphenol A, bisphenol F, 3,3',5,5'-tetramethyl-4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, fluorene bisphenol, 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-dihydroxynaphthalene, allylated or polyallylated products of the above dihydroxynaphthalenes, allylated bisphenol A, allylated bisphenol F, allylated phenol novolac and other divalent phenols, 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(4-hydroxyphenyl)ethane, fluoroglycinol, pyrogallol, t-butylpyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2,4-benzenetriol, 2,3,4-trihydroxybenzophenone, phenol aralkyl resin, naphthol aralkyl resin, dicyclopentadiene-based resin and other trivalent or higher phenols, or glycidyl ether compounds derived from halogenated bisphenols such as tetrabromobisphenol A. These epoxy resins can be used alone or in combination of two or more.

[0039] It is desirable that the epoxy resin composition of the present invention contains the epoxy resin of the general formula (1) as an epoxy resin component in an amount of 50 wt% or more. More preferably, it is 70 wt% or more, still more preferably 80 wt% or more of all the epoxy resins. If the usage ratio is less than this, the moldability as an epoxy resin composition deteriorates, and the effects of improving heat resistance, thermal conductivity, etc. when formed into a cured product are small.

[0040] As the curing agent used in the epoxy resin composition of the present invention, all those generally known as curing agents for epoxy resins can be used, and there are dicyandiamide, acid anhydrides, polyhydric phenols, aromatic and aliphatic amines, etc. Among these, in fields where high electrical insulation such as semiconductor encapsulants is required, it is preferable to use polyhydric phenols as the curing agent. The polyhydroxy resin represented by the general formula (3) of the present invention is suitable as a curing agent. When the polyhydroxy resin of the present invention is used as a curing agent for an epoxy resin, it is desirable to contain the polyhydroxy resin of the formula (3) as a curing agent in an amount of 50 wt% or more. Specific examples of the curing agent are shown below.

[0041] Examples of polyhydric phenols include dihydric phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, naphthalenediol, etc., or polyhydric phenols represented by tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phenol novolak, o-cresol novolak, naphthol novolak, polyvinylphenol, etc. Furthermore, there are polyhydric phenolic compounds synthesized from condensers such as phenols, naphthols, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, naphthalenediol, etc. and condensers such as formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, p-xylylene glycol, etc.

[0042] Examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhimic anhydride, dodecenylsuccinic anhydride, nadic anhydride, trimellitic anhydride, etc.

[0043] Examples of amine curing agents include aromatic amines such as 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylsulfone, m-phenylenediamine, p-xylylenediamine, etc., and aliphatic amines such as ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, etc.

[0044] One or more of these curing agents can be mixed and used in the above epoxy resin composition.

[0045] The blending ratio of the epoxy resin and the curing agent is preferably in the range of 0.8 to 1.5 in terms of the equivalent ratio of the epoxy group and the functional group in the curing agent. Outside this range, unreacted epoxy groups or functional groups in the curing agent remain after curing, which is not preferable because the reliability regarding the sealing function decreases.

[0046] In the epoxy resin composition of the present invention, oligomers or high molecular compounds such as polyester, polyamide, polyimide, polyether, polyurethane, petroleum resin, indene resin, indene-cumarone resin, and phenoxy resin may be appropriately blended as other modifiers or the like. The addition amount is usually in the range of 1 to 30 parts by weight with respect to 100 parts by weight in total of the resin components.

[0047] Additives such as inorganic fillers, pigments, flame retardants, thixotropic agents, coupling agents, and fluidity improvers can be blended in the epoxy resin composition of the present invention. Examples of the inorganic filler include silica powder such as spherical or crushed fused silica and crystalline silica, alumina powder, glass powder, or mica, talc, calcium carbonate, alumina, hydrated alumina, etc. The preferable blending amount when used as a semiconductor encapsulant is 70% by weight or more, and more preferably 80% by weight or more.

[0048] In order to increase the thermal conductivity, for example, inorganic fillers such as glass cloth, carbon fiber, alumina, and boron nitride may be blended.

[0049] For the purpose of imparting a higher thermal conductivity, the inorganic filler is preferably one with a higher thermal conductivity. Preferably it is 20 W / m·K or more, more preferably 30 W / m·K or more, and still more preferably 50 W / m·K or more. And at least a part of the inorganic filler, preferably 50 wt% or more, has a thermal conductivity of 20 W / m·K or more. And the average thermal conductivity of the whole inorganic filler is preferably improved in the order of 20 W / m·K or more, 30 W / m·K or more, and 50 W / m·K or more.

[0050] Examples of the inorganic filler having such a thermal conductivity include inorganic powder fillers such as boron nitride, aluminum nitride, silicon nitride, silicon carbide, titanium nitride, zinc oxide, tungsten carbide, alumina, magnesium oxide, and the like.

[0051] Examples of the pigment include organic or inorganic extender pigments, flaky pigments, and the like. Examples of the thixotropic agent include silicone-based, castor oil-based, aliphatic amide wax, polyethylene oxide wax, organic bentonite-based, and the like.

[0052] A curing accelerator can be used in the epoxy resin composition of the present invention as needed. Examples include amines, imidazoles, organic phosphines, Lewis acids, etc. Specifically, tertiary amines such as 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris(dimethylaminomethyl)phenol, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine, tetra-substituted phosphonium tetra-substituted borates such as tetraphenylphosphonium·tetraphenylborate, tetraphenylphosphonium·ethyltriphenylborate, tetrabutylphosphonium·tetrabutylborate, and tetraphenylboron salts such as 2-ethyl-4-methylimidazole·tetraphenylborate, N-methylmorpholine·tetraphenylborate. The addition amount is usually in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight in total of the resin components.

[0053] 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-reducing agents such as silicone oil, lubricants such as calcium stearate, and the like.

[0054] The epoxy resin composition of the present invention can be made into a prepreg by dissolving it in an organic solvent to form a varnish state, impregnating fibrous materials such as glass cloth, aramid non-woven fabric, polyester non-woven fabric such as liquid crystal polymer, and then removing the solvent. Further, it can be made into a laminate by coating it on a sheet material such as copper foil, stainless steel foil, polyimide film, or polyester film as the case may be.

[0055] By heat-curing the epoxy resin composition of the present invention, a cured resin of the present invention can be obtained. This cured product can be obtained by molding the epoxy resin composition by methods such as casting, compression molding, and transfer molding. The temperature at this time is usually in the range of 120 to 220°C.

Examples

[0056] Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not limited thereto. Unless otherwise specified, "parts" represents parts by weight and "%" represents weight %. Also, the measurement methods were measured by the following methods respectively.

[0057] 1) Epoxy equivalent Using a potentiometric titration apparatus, methyl ethyl ketone was used as a solvent, a brominated tetraethylammonium acetate solution was added, and it was measured with a 0.1 mol / L perchloric acid - acetic acid solution using the potentiometric titration apparatus.

[0058] 2) OH equivalent (hydroxyl equivalent) Using a potentiometric titration apparatus, acetylation was carried out with 1,4-dioxane as the solvent using 1.5 mol / L acetyl chloride. The excess acetyl chloride was decomposed with water and titrated using 0.5 mol / L potassium hydroxide.

[0059] 3) Softening point It was measured by the ring and ball method in accordance with JIS-K-2207.

[0060] 4) GPC measurement A device equipped with four columns (TSKgel SuperMultiporeHZ manufactured by Tosoh Corporation) in series was used for the main body (HLC-8220GPC manufactured by Tosoh Corporation), and the column temperature was set to 40 °C. Tetrahydrofuran (THF) was used as the eluent, the flow rate was 0.35 mL / min, and a differential refractive index detector was used as the detector. As the measurement sample, 50 μL of a solution prepared by dissolving 0.1 g of the sample in 10 mL of THF and filtering it through a microfilter was used. For data processing, GPC-8020 Model II Version 6.00 manufactured by Tosoh Corporation was used.

[0061] 5) Solvent solubility (precipitation temperature) 2 g of the resin 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 thermostatic bath, and the temperature in the bath at which the resin precipitated was measured. The higher the precipitation temperature (°C), the poorer the solvent solubility.

[0062] 6) Glass transition point (Tg) The Tg was determined by a thermomechanical measurement device (EXSTAR TMA / 7100 manufactured by SII NanoTechnology Inc.) under the condition of a heating rate of 10 °C / min.

[0063] 7) 5% weight loss temperature (Td5), char yield Using a thermogravimetric / differential thermal analyzer (EXSTAR TG / DTA7300 manufactured by SII NanoTechnology Inc.), the 5% weight loss temperature (Td5) was measured under a nitrogen atmosphere at a heating rate of 10 °C / min. Also, the weight loss at 700 °C was measured and calculated as the char yield.

[0064] 8) Thermal conductivity The thermal conductivity was measured by the transient hot wire method using a NETZSCH LFA447 thermal conductivity meter.

[0065] (Example 1) Into a 1000 ml four-necked flask, 140.3 g (0.48 mol) of 4,4’,4”-trihydroxytriphenylmethane (the following structural formula),

Chemical formula

Chemical formula

[0066] (Example 2) The same operations as in Example 1 were carried out except that the amount of 4,4’,4”-trihydroxytriphenylmethane used was 116.9 g (0.40 mol), and 142.5 g of hydroxy resin b was obtained. The hydroxyl equivalent of the obtained hydroxy resin b was 205 g / eq., Mn was 980, and the area percentage of n≥1 species in GPC was 80.0% (n = 0 species was 20.0%).

[0067] (Example 3) Instead of 4,4'-bis(chloromethyl)biphenyl, 27.5 g (0.16 mol) of 2,6-dichlorobenzonitrile (the following structural formula) [Chemical formula] was used, and the same operations as in Example 1 were carried out to obtain 149.3 g of hydroxy resin c. The hydroxyl equivalent of the obtained hydroxy resin c was 158 g / eq., Mn was 580, and the percentage of the n≥1 form in terms of GPC area was 60.7% (the n = 0 form was 39.3%).

[0068] (Example 4) Instead of 4,4'-bis(chloromethyl)biphenyl, 45.9 g (0.16 mol) of 4,4'-dichlorodiphenyl sulfone (the following structural formula) [Chemical formula] was used, and the same operations as in Example 1 were carried out to obtain 170.2 g of hydroxy resin d. The hydroxyl equivalent of the obtained hydroxy resin d was 180 g / eq., Mn was 720, and the percentage of the n≥1 form in terms of GPC area was 67.5% (the n = 0 form was 32.5%).

[0069] (Example 5) Instead of 4,4'-bis(chloromethyl)biphenyl, 36.8 g (0.16 mol) of 1,4-dibromobutane (the following structural formula) [Chemical formula] was used, and the same operations as in Example 1 were carried out to obtain 147.2 g of hydroxy resin e. The hydroxyl equivalent of the obtained hydroxy resin e was 159 g / eq., Mn was 560, and the percentage of the n≥1 form in terms of GPC area was 52.7% (the n = 0 form was 47.3%).

[0070] (Example 6) Instead of 4,4'-bis(chloromethyl)biphenyl, 28.0 g (0.16 mol) of p-xylene dichloride (the following structural formula) [Chemical formula] The same operations as in Example 1 were performed except that [specific reagent or condition] was used, and 152.1 g of hydroxy resin f was obtained. The hydroxyl equivalent of the obtained hydroxy resin f was 177 g / eq., Mn was 960, and the percentage of the n ≥ 1 species in terms of GPC area was 71.9% (the n = 0 species was 28.1%).

[0071] (Example 7) Into a 1000 ml four-necked flask, 94.0 g (0.50 equivalent) of the hydroxy resin a obtained in Example 1 and 460 g of epichlorohydrin (the following structural formula) [Chemical formula] were added. While under reduced pressure (about 130 Torr) at 62 °C, 50.0 g of a 48% aqueous sodium hydroxide solution was added dropwise over 4 hours. During this time, the water generated was removed from the system by azeotropy with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the dropwise addition was completed, the reaction was continued for another 1 hour. Then, epichlorohydrin was distilled off, methyl isobutyl ketone was added, and after removing salts by washing with water, filtration and washing with water were performed. Next, methyl isobutyl ketone was distilled off under reduced pressure to obtain 103.2 g of an epoxy resin (epoxy resin A). The epoxy equivalent of this epoxy resin A was 243, the softening point was 72 °C, the hydrolyzable chlorine was 50 ppm, Mn was 740, and the percentage of the n ≥ 1 species measured by GPC was 75.2% (the n = 0 component was 24.8%). The GPC chart of the obtained resin is shown in Figure 1.

[0072] (Example 8) The same operations as in Example 7 were performed except that 102.5 g (0.50 equivalent) of the hydroxy resin b obtained in Example 2 was used instead of the hydroxy resin a, and 109.6 g of an epoxy resin (epoxy resin B) was obtained. The epoxy equivalent of epoxy resin B was 261 g / eq., the softening point was 79 °C, the hydrolyzable chlorine was 57 ppm, Mn was 980, and the percentage of the n ≥ 1 species in terms of GPC area was 81.1% (the n = 0 species was 18.9%).

[0073] (Example 9) The same procedure as in Example 7 was carried out except that 79.0 g (0.50 equivalent) of the hydroxy resin c obtained in Example 3 was used instead of the hydroxy resin a, and 88.6 g of an epoxy resin was obtained (Epoxy Resin C). The epoxy equivalent of Epoxy Resin C was 213 g / eq., the softening point was 78 °C, the hydrolyzable chlorine was 60 ppm, Mn was 570, and the percentage of the n≥1 species by GPC area was 65.1% (the n = 0 species was 34.9%).

[0074] (Example 10) The same procedure as in Example 7 was carried out except that 90.0 g (0.50 equivalent) of the hydroxy resin d obtained in Example 4 was used instead of the hydroxy resin a, and 102.2 g of an epoxy resin was obtained (Epoxy Resin D). The epoxy equivalent of Epoxy Resin D was 238 g / eq., the softening point was 84 °C, the hydrolyzable chlorine was 70 ppm, Mn was 650, and the percentage of the n≥1 species by GPC area was 72.1% (the n = 0 species was 27.9%).

[0075] (Example 11) The same procedure as in Example 7 was carried out except that 79.5 g (0.50 equivalent) of the hydroxy resin e obtained in Example 5 was used instead of the hydroxy resin a, and 84.9 g of an epoxy resin was obtained (Epoxy Resin E). The epoxy equivalent of Epoxy Resin E was 215 g / eq., the softening point was 84 °C, the hydrolyzable chlorine was 85 ppm, Mn was 580, and the percentage of the n≥1 species by GPC area was 59.8% (the n = 0 species was 40.2%).

[0076] (Example 12) The same procedure as in Example 7 was carried out except that 88.5 g (0.30 equivalent) of the hydroxy resin f obtained in Example 6 was used instead of the hydroxy resin a, and 102.6 g of an epoxy resin was obtained (Epoxy Resin F). The epoxy equivalent of Epoxy Resin F was 233 g / eq., the softening point was 70 °C, the hydrolyzable chlorine was 50 ppm, Mn was 970, and the percentage of the n≥1 species by GPC area was 74.0% (the n = 0 species was 26.0%).

[0077] (Reference Example 1) The same procedure as in Example 7 was carried out except that 48.7 g (0.50 equivalent) of 4,4’,4”-trihydroxytriphenylmethane (the above structural formula) was used instead of hydroxy resin a, and 72.4 g of an epoxy resin was obtained (epoxy resin G). The epoxy equivalent of epoxy resin G was 155 g / eq., the softening point was 50 °C, the hydrolyzable chlorine was 40 ppm, Mn was 410, and the n≥1 species was 2.0% (the n = 0 species was 98.0%) in terms of GPC area%.

[0078] (Reference Example 2) Into a 1000 ml four-necked flask, 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’-bis(chloromethyl)biphenyl were charged. While stirring under a nitrogen stream, the temperature was raised to 170 °C and reacted for 10 hours to produce a polyhydroxy resin. After completion of the reaction, 50.7 g of diethylene glycol dimethyl ether was recovered, 470 g of epichlorohydrin was added, and 68.7 g of a 48% aqueous sodium hydroxide solution was added dropwise at 62 °C under reduced pressure (about 130 Torr) over 4 hours. During this time, the water produced was removed from the system by azeotropy with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After completion of the dropwise addition, the reaction was continued for another 1 hour. Then, epichlorohydrin was distilled off, methyl isobutyl ketone was added, and after removing salts by washing with water, filtration and washing with water were carried out. Next, methyl isobutyl ketone was distilled off under reduced pressure to obtain 130 g of an epoxy resin (epoxy resin H). The epoxy equivalent of this epoxy resin H was 196, the softening point was 97 °C, the hydrolyzable chlorine was 65 ppm, Mn was 450, and the n≥1 species measured by GPC was 72.0% (the n = 0 component was 28.0%).

[0079] Examples 13 to 19, Comparative Examples 1 to 3 As the epoxy resin component, epoxy resins A to F obtained in Examples 7 to 12, epoxy resins G to H obtained in Reference Examples 1 to 2, and epoxy resin I; o-cresol novolak type epoxy resin (YDCN-700-3 manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent 200) were used. As the curing agent, polyhydroxy resin a obtained in Example 1 and phenol novolak resin g (hydroxyl equivalent 105) were used. As the curing accelerator, triphenylphosphine was used, and an epoxy resin composition was obtained with the formulation shown in Table 1. The numerical values in the table indicate parts by weight in the formulation. Using this epoxy resin composition, it was molded at 175°C and post-cured at 175°C for 5 hours to obtain a cured test piece, which was then used for various physical property measurements. The results are also shown in Table 1.

[0080]

Table 1

[0081] The epoxy resins and polyhydroxy resins as curing agents in the examples showed excellent physical properties such as excellent solvent solubility, high thermal conductivity, and high heat resistance compared to the comparative examples.

Industrial Applicability

[0082] The polyhydroxy resin and epoxy resin of the present invention are suitable for power devices and in-vehicle 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). 【Chemical 1】 In formula (1), R1 to R6 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and X independently represents a structure represented by formula (2), a benzonitrile structure, a diphenylsulfonyl structure, a xylylene structure, or -(CH ２ ) ｍ -, m represents a number from 3 to 10, and n represents a number from 1 to 15. 【Chemical Formula 2】

2. The epoxy resin according to Claim 1, wherein X has the structure represented by formula (2).

3. A polyhydroxy resin represented by the following general formula (3). [Chemical Formula 3] In formula (3), R1 to R6 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and X independently represents a structure represented by formula (2), a benzonitrile structure, a diphenylsulfonyl structure, a xylylene structure, or -(CH ２ ) ｍ -, m represents a number from 3 to 10, and n represents a number from 1 to 15.

4. The polyhydroxy resin according to Claim 3, wherein X has the structure represented by formula (2).

5. An epoxy resin composition comprising an epoxy resin and a curing agent, wherein the epoxy resin composition contains, as part or all of the epoxy resin, the epoxy resin according to Claim 1 as an essential component.

6. A resin composition characterized by containing, as an essential component, the polyhydroxy resin according to Claim 3.

7. A resin cured product obtained by curing the resin composition according to any one of Claims 5 or 6.

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