CN117043215A

CN117043215A - Epoxy resin, curable resin composition, and cured product of curable resin composition

Info

Publication number: CN117043215A
Application number: CN202280022791.0A
Authority: CN
Inventors: 中西政隆; 吉田圭汰; 板井政幸; 関允谕
Original assignee: Nippon Kayaku Co Ltd
Current assignee: Nippon Kayaku Co Ltd
Priority date: 2021-06-18
Filing date: 2022-06-17
Publication date: 2023-11-10
Also published as: WO2022265096A9; WO2022265096A1; KR20240021736A; TW202313751A; JPWO2022265096A1; JP7230285B1

Abstract

The invention provides an epoxy resin and a curable resin composition, which have excellent heat resistance and tracking resistance of a cured product thereof. An epoxy resin having a value obtained by dividing the epoxy equivalent (g/eq.) by the softening point (DEG C) of 2.0 or more and less than 2.2, represented by the following formula (1). ( In the formula (1), a plurality of R independently exist and represent methyl or hydrogen atoms; n is the average value of repetition number and is a real number of 1-10 )

Description

Epoxy resin, curable resin composition, and cured product of curable resin composition

Technical Field

The present invention relates to an epoxy resin having a specific structure, a curable resin composition, and a cured product of the curable resin composition.

Background

Epoxy resins are widely used in the fields of electric and electronic fields such as casting molded articles, laminated boards, and integrated circuit (integrated circuit, IC) sealing materials, structural materials, adhesives, and paints, because they are excellent in electric properties (dielectric constant/dielectric loss tangent, insulation), mechanical properties, adhesion, thermal properties (heat resistance, etc.), and the like.

In recent years, in the electric and electronic fields, further improvements in properties such as improvement in flame retardancy, moisture resistance, adhesion, dielectric properties, and the like, higher purity, reduction in viscosity for highly filling a filler (inorganic filler or organic filler), and improvement in reactivity for shortening a molding cycle have been demanded for resin compositions (patent document 1). In addition, as a structural material, a lightweight material having excellent mechanical properties is required for aerospace materials, leisure/sports equipment applications, and the like.

In the field of semiconductor sealing, the substrate (substrate itself or its peripheral material) is complicated by the reduction in thickness, stacking, systemization, and three-dimensional formation of the semiconductor with the transition of the semiconductor, and a very high level of required characteristics such as heat resistance and high fluidity are required. In particular, as plastic packaging expands in vehicle applications, the demand for improved heat resistance becomes more stringent. Specifically, with the rise in driving temperature of semiconductors, very high heat resistance is required, and in recent years, there is a trend toward a wide bandgap semiconductor, and it is also required to cope with driving temperatures of 175 ℃ or even 200 ℃ or higher. For the driving temperature, the peripheral member is required to have sufficient heat resistance (Tg in glass transition temperature (Tg), particularly in thermo-mechanical characteristics (thermo-mechanical analysis (thermomechanical analysis, TMA)). Specifically, a temperature higher than the driving temperature by about 10% (in the case of 200 ℃, tg of 220 ℃ or higher, for example 225 ℃) is required, and the temperature is required to be increased year by year (non-patent document 1).

In recent years, among demands for electric vehicles and the like, demands for high-voltage power devices have been rapidly increased, and tracking resistance has been paid attention to. In addition, in applications such as solar power generation, wind power generation, and Electric Vehicles (EVs), tracking resistance is also important, and in particular, in severe applications, it is required that the tracking index (Comparative Tracking Index, CTI) exceeds 600.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2019-001841

Non-patent literature

Non-patent document 1: fuji motor technical report 2016, volume 89, 4, pages 247-250 (2016vol.89No.4 247-250)

Disclosure of Invention

Problems to be solved by the invention

Generally, an aromatic crosslinking unit is sometimes introduced for the purpose of improving the heat resistance of the resin composition, but in this case, since the main skeleton is aromatic, carbonization is easy and tracking resistance is lowered. In addition, when the heat resistance is improved by increasing the molecular weight, the molecular weight increases, so that the thermal decomposition temperature increases, and the tracking resistance decreases. That is, heat resistance has a trade-off relationship with the tracking characteristic, so it is very difficult to remove the tracking characteristic while maintaining heat resistance. Further, when a resin containing a multi-sensory aromatic compound is blended in order to impart properties such as flame retardancy, the tracking resistance is liable to deteriorate, and it is difficult to achieve both high tracking resistance and flame retardancy.

In general, material performance ratings (performance level category, PLC) are set according to the value of CTI. Since the PLC is classified into a smaller one, the size (surface distance) of the design of the device can be reduced, and the PLC is preferably 3 or less, and particularly preferably 1 or less.

Further, the PLC and CTI have the following relationship.

PLC1: CTI600 or more, PLC2: CTI400 or more and less than 600, PLC3:250 or more and less than 400, plc4:100 or more and less than 175, plc5: less than 100.

The present application has been made in view of such circumstances, and an object thereof is to provide an epoxy resin and a curable resin composition which are excellent in heat resistance and tracking resistance of cured products thereof.

Technical means for solving the problems

The present inventors have made an effort to solve the above problems, and as a result, have completed the present application. That is, the present application relates to the following [1] to [3]. In the present application, "(numerical values 1) to" (numerical value 2) "means that the upper and lower limit values are included.

[1]

An epoxy resin having a value obtained by dividing the epoxy equivalent (g/eq.) by the softening point (DEG C) of 2.0 or more and less than 2.2, represented by the following formula (1).

[ chemical 1]

(in the formula (1), R in the presence of a plurality of R independently represents methyl or hydrogen atom, n is the average value of repetition number and is a real number of 1-10)

[2]

A curable resin composition comprising the epoxy resin according to the above item [1 ].

[3]

The curable resin composition according to the preceding item [2], wherein the content of the inorganic filler is 74% by weight or more and 95% by weight or less in the total amount of the curable resin composition.

[4]

A cured product obtained by curing the curable resin composition according to the above [2] or the above [3 ].

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention relates to an epoxy resin having a specific structure, a curable resin composition, and a cured product thereof, which cured product has excellent heat resistance and tracking resistance.

Therefore, the present invention is effectively used for insulating materials (high-reliability semiconductor sealing materials and the like) for electric and electronic parts, laminated boards (printed wiring boards, build-up boards and the like), various composite materials typified by carbon fiber reinforced plastics (carbon fiber reinforced plastic, CFRP), adhesives, paints and the like.

Drawings

FIG. 1 shows a gel permeation chromatography (gel permeation chromatography, GPC) chart of Synthesis example 1.

FIG. 2 shows a GPC chart of Synthesis example 2.

FIG. 3 shows a GPC chart of Synthesis example 3.

FIG. 4 shows a GPC chart of example 1.

FIG. 5 shows a GPC chart of example 2.

FIG. 6 shows a GPC chart of example 3.

FIG. 7 shows a GPC chart of comparative Synthesis example 1.

FIG. 8 shows a GPC chart of comparative Synthesis example 2.

FIG. 9 shows a GPC chart of FAE-2500.

FIG. 10 shows TMA charts of example 4, example 5, comparative example 1, and comparative example 2.

FIG. 11 shows a GPC chart of Synthesis example 4.

FIG. 12 shows a GPC chart of example 7.

FIG. 13 shows the CTI measurement results of examples 10 to 13 and comparative examples 5 to 8.

Detailed Description

The epoxy resin of the present invention is represented by the following formula (1), and has a value obtained by dividing the epoxy equivalent (g/eq.) by the softening point (. Degree. C.) of 2.0 or more and less than 2.2.

[ chemical 2]

(in the formula (1), a plurality of R independently exist, the R represents methyl or hydrogen atom, n is the average value of repeated numbers, and the n is a real number of 1-10).

In the above formula (1), n is calculated from the number average molecular weight obtained by gel permeation chromatography (GPC, detector: UV (ultraviolet) 254 nm) measurement or the area ratio of each of the separated peaks, and is preferably a real number of 1 to 5, particularly preferably a real number of 2 to 4.

When n=1 in the formula (1), it is preferably less than 50 area%, and more preferably less than 45 area%. In addition, the lower limit is 25 area%, and in the case where the lower limit is less than 25 area%, the fluidity of the resin is poor, and in the case where the resin is used as a sealing material, the productivity is deteriorated. As an index of fluidity, when the viscosity (ICI melt viscosity) is measured at 150 ℃ by the cone-plate method using the melt viscosity in the resin as an index, the viscosity is preferably 2pa·s or less. In addition, if the viscosity is too low, air or the like may be involved in molding to form voids, and blocking or the like may occur in blending (or modifying) a liquid resin or the like, so that it is preferably 0.4pa·s or more. Further, in view of the balance between heat resistance and thermal decomposition properties, it is preferably 0.45pa·s or more, and particularly preferably 0.5pa·s or more.

The compound having n of formula (1) of less than 1 is preferably contained in an amount of 0.5 to 10% by area, more preferably 0.5 to 5% by area, and particularly preferably 0.5 to 2.5% by area. Since the compound having n of less than 1 is a compound having a structure of less than 3 functions or an epoxy resin of t-butyl methylphenol, when the compound having n of less than 1 exceeds 10 area%, not only is the heat resistance suggested to be lowered, but there is a concern that odor or adverse effects on the human body during handling may be caused. On the other hand, when the compound having n of less than 1 is less than 0.5 area%, there is a concern that the weight reduction by thermal decomposition becomes large due to the network becoming too dense, and the thermal decomposition characteristics are adversely affected (and thus the tracking characteristics are presumed to be adversely affected).

The epoxy resin of the present invention is usually in the form of a resin solid at ordinary temperature, and its softening point is preferably 90℃or higher, more preferably 95℃or higher. In addition, the upper limit thereof is 150 ℃. When the softening point is higher than 150 ℃, solvent tends to remain when the resin is taken out, and voids tend to be formed when the resin is cured. In addition, foaming and the like are easy to occur during distillation of the solvent, and problems in production are also large. On the other hand, when the softening point is 90 ℃ or lower, the heat resistance and the thermal decomposition resistance are adversely affected. The epoxy equivalent is preferably 200g/eq to 300g/eq, and more preferably 205g/eq to 250g/eq. In the case where the epoxy equivalent is less than 200g/eq. The epichlorohydrin remains, or a large amount of epoxide remains as an impurity, and there is a possibility of deterioration of characteristics. In addition, when the content exceeds 300g/eq, the heat resistance is deteriorated.

In the present invention, the epoxy equivalent is measured by a method based on Japanese Industrial Standard (Japanese Industrial Standards, JIS) K-7236. The softening point was measured using a METTLER tolido (METTLER TOLEDO) company softening point determinator FP 90.

The epoxy resin of the present invention is preferably an epoxy resin having a high softening point and a large number of functional groups per unit molecular weight. The softening point tends to be higher as the molecular weight is larger. This means that the softening point is the temperature at which fluidity of the resin is observed when heated, and the larger the molecular weight, the more difficult the molecules are to move, i.e., the softening point rises. On the other hand, it is considered that, as the softening point increases, the heat resistance increases, but it is more effective to increase the number of functional groups per unit weight with respect to the increase in heat resistance, and the epoxy equivalent is a value related to the number of functional groups.

When the softening point is small and the epoxy equivalent is large, it is suggested that the functional group per molecule is small, whereas when the softening point is high and the epoxy equivalent is small, it is known that the functional group per molecule is large. Therefore, a compound having a high softening point and a small epoxy equivalent is preferable.

In the present invention, the value obtained by dividing the epoxy equivalent (g/eq.) by the softening point (. Degree. C.) is set as the parameter A, and the parameter A is preferably 2.0 or more and less than 2.2. When the parameter a is less than 2.0, it is considered that some impurities remain because the epoxy equivalent is too small, whereas when it is 2.2 or more, it means that the epoxy equivalent is large, the softening point is low relative to the value of the epoxy equivalent, and heat resistance and thermal decomposition characteristics cannot be achieved at the same time.

Here, the thermal decomposition characteristic is considered to be a parameter affecting the tracking resistance, and it is considered that the lower the thermal decomposition temperature in the tracking test, the more difficult it is to conduct between the electrodes, and thus the higher the withstand voltage can be. In general, if the molecular weight is increased, the thermal decomposition temperature tends to rise, but in the present invention, even if the molecular weight is increased, there is no large difference in the thermal decomposition temperature, and it is considered that the high tracking resistance can be maintained.

The method for producing the epoxy resin of the present invention is not particularly limited, and it can be obtained, for example, by causing an addition or ring closure reaction between a phenol resin represented by the following formula (2) and an epihalohydrin in the presence of a solvent and a catalyst.

[ chemical 3]

(in the formula (2), a plurality of R independently exist, and represent methyl or hydrogen atoms, and n is an average value of repetition numbers and is a real number of 1-10).

In the formula (2), n can be calculated from the number average molecular weight obtained by measurement by gel permeation chromatography (GPC, detector: UV 254 nm) or the area ratio of each of the separated peaks. n is further preferably 1 to 5, particularly preferably 1 to 3.

The hydroxyl equivalent weight of the phenol resin of formula (2) is preferably 140g/eq to 180g/eq, more preferably 140g/eq to 165g/eq. The amount of the compound having n=1 is preferably 30 to 60 area%, more preferably 40 to 60 area%. The total of the compounds having n of 2 or more is preferably 25 to 40 area%.

Here, a method for producing the phenol resin represented by the above formula (2) will be described.

The method for producing the phenol resin represented by the formula (2) is not particularly limited, and specifically, alkylphenols (3-methyl-6-t-butylphenol and 4-methyl-2-t-butylphenol) and parahydroxybenzaldehyde are polycondensed under acidic conditions to obtain novolak. Preferably, the ratio of alkylphenol (3-methyl-6-t-butylphenol and 4-methyl-2-t-butylphenol) to parahydroxyben-zaldehyde is 3: 2-2: 1, and the reaction was carried out. The ratio of 3-methyl-6-t-butylphenol to 4-methyl-2-t-butylphenol is preferably 3-methyl-6-t-butylphenol in 90% by weight or more of alkylphenols, and the ratio is adjusted by the amount of alkylphenol blended at the time of producing the phenol resin. Specifically, alkylphenol as a raw material is added in accordance with the introduction ratio of the target alkylphenol.

The hydroxyl group equivalent of the obtained phenol resin is preferably 140g/eq to 170g/eq, more preferably 145g/eq to 165g/eq, and particularly preferably 150g/eq to 160g/eq.

The acidic catalyst used in synthesizing the phenol resin represented by the above formula (2) may be exemplified by: hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, zinc chloride, ferric chloride, aluminum chloride, p-toluenesulfonic acid, methanesulfonic acid, activated clay, ion exchange resins and the like. These may be used alone or in combination of two or more. The amount of the catalyst to be used is 0.1 to 50% by weight, preferably 1 to 30% by weight, based on the phenolic hydroxyl groups to be used, and if the amount is too large, the amount of waste is increased, and if the amount is too small, the progress of the reaction is slowed.

The reaction may be carried out using an organic solvent as needed, or may be carried out in the absence of a solvent. Among them, water to be purified in the reaction is azeotropically dehydrated to more efficiently carry out the reaction, and therefore, a solvent which can azeotropically react with water is preferably used. In the present invention, it is particularly preferable to use a hydrocarbon-based organic solvent such as toluene or xylene.

Thereafter, the resin is taken out after the solvent is flowed through the washing with water, neutralization, or the like, or the resin may be taken out by a method such as reprecipitation or recrystallization. Since the softening point of the phenol resin represented by the above formula (2) is extremely high, it is preferably extracted by a method such as reprecipitation or recrystallization, and for example, a method of replacing the solvent with a poor solvent to precipitate the same can be used.

The phenol resin represented by the formula (2) is a crystalline or resin solid, and the ratio of n=1 in GPC in this case is preferably less than 60%. Particularly 55 area% or less, and further 50 area% or less. The total amount of the residual raw material monomers is preferably 5 area% or less, and each peak is preferably less than 1.5 area%. The amount of the monomer affects the residual amount of the epoxy resin having a low molecular weight, and the amount affects heat resistance and the like.

Next, a method for producing the epoxy resin of the present invention will be described.

As described above, the method for producing the epoxy resin of the present invention is not particularly limited, and the epoxy resin can be obtained, for example, by subjecting the phenol resin represented by the formula (2) and an epihalohydrin to addition or ring-closure reaction in the presence of a solvent and a catalyst.

The epihalohydrin is used in an amount of usually 1.0 to 20.0 mol, preferably 1.5 to 10.0 mol, based on 1 mol of phenolic hydroxyl groups of the phenol resin.

Examples of the alkali metal hydroxide that can be used in the epoxidation reaction include sodium hydroxide and potassium hydroxide. The alkali metal hydroxide may be a solid substance, or an aqueous solution thereof may be used. In the case of using an aqueous solution, the following method may be used: the aqueous alkali metal hydroxide solution is continuously added to the reaction system, and water and epihalohydrin are continuously distilled off under reduced pressure or normal pressure, and then separated to remove water, whereby epihalohydrin is continuously returned to the reaction system. The amount of the alkali metal hydroxide to be used is usually 0.9 to 2.5 moles, preferably 0.95 to 1.5 moles, based on 1 mole of the phenolic hydroxyl groups of the phenol resin. If the amount of the alkali metal hydroxide used is small, the reaction does not proceed sufficiently. On the other hand, the use of an alkali metal hydroxide in an amount exceeding 2.5 moles based on 1 mole of phenolic hydroxyl groups of the phenol resin results in the by-production of unnecessary waste.

In order to promote the reaction, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, trimethylbenzyl ammonium chloride, etc. may be added as a catalyst. The amount of the quaternary ammonium salt used is usually 0.1g to 15g, preferably 0.2g to 10g, based on 1 mol of phenolic hydroxyl groups of the phenol resin. If the amount is too small, a sufficient reaction promoting effect cannot be obtained, and if the amount is too large, the amount of quaternary ammonium salt remaining in the epoxy resin increases, which may cause deterioration of electrical reliability.

In the epoxidation reaction, it is preferable to add alcohols such as methanol, ethanol and isopropanol, aprotic polar solvents such as dimethyl sulfone, dimethyl sulfoxide, tetrahydrofuran and dioxane for the reaction. In the case of using an alcohol, the amount thereof is usually 2 to 50% by weight, preferably 4 to 20% by weight, relative to the amount of the epihalohydrin. In the case of using the aprotic polar solvent, the amount of the epihalohydrin to be used is usually 5 to 100% by weight, preferably 10 to 80% by weight. The reaction temperature is usually 30℃to 90℃and preferably 35℃to 80 ℃. The reaction time is usually 0.5 to 100 hours, preferably 1 to 30 hours.

After the reaction, the reaction product is washed with water, or the epihalohydrin, the solvent, or the like is removed under reduced pressure and heating without washing with water. In order to produce an epoxy resin having less hydrolyzable halogen, the recovered epoxy resin may be dissolved in a solvent such as toluene or methyl isobutyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide may be added to react with each other to thereby ensure ring closure. In this case, the amount of the alkali metal hydroxide to be used is usually 0.01 to 0.3 mol, preferably 0.05 to 0.2 mol, based on 1 mol of phenolic hydroxyl groups of the phenol resin used for glycidation. The reaction temperature is usually 50 to 120 ℃, and the reaction time is usually 0.5 to 24 hours. After the completion of the reaction, the produced salt is removed by filtration, washing with water or the like, and then the solvent is distilled off under reduced pressure with heating, whereby the epoxy resin of the present invention is obtained.

Hereinafter, the curable resin composition of the present invention will be described.

The epoxy resin represented by the formula (1) may be used alone or in combination with other epoxy resins. When the epoxy resin represented by the formula (1) is used in combination, the proportion of the epoxy resin is preferably 10 to 98% by weight, more preferably 30 to 95% by weight, and still more preferably 60 to 95% by weight, based on the total amount of the epoxy resins. By setting the addition amount of the epoxy resin represented by the above formula (1) to 10% or more, an improvement in the elastic modulus and a low water absorption can be exhibited.

Specific examples of the other epoxy resin that can be used in combination with the epoxy resin represented by the above formula (1) include: polycondensates of bisphenols (bisphenol a, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.) or phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) with various aldehydes (formaldehyde, acetaldehyde, alkyl aldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthalene aldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.); polymers of the phenols with various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, caspoylbiphenyl, butadiene, isoprene, etc.); polycondensates of said phenols with ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.); polycondensates of the above-mentioned phenols with aromatic diols (such as xylylene glycol and biphenyldimethanol); polycondensates of the above phenols with aromatic dichloromethyl groups (α, α' -dichloroxylene, dichloromethyl biphenyl, etc.); polycondensates of the phenols with aromatic dialkoxymethyl groups (dimethoxymethylbenzene, dimethoxymethylbiphenyl, diphenoxymethylbiphenyl, etc.); the polycondensates of the bisphenol and various aldehydes or glycidyl ether-based epoxy resins, alicyclic epoxy resins, glycidyl amine-based epoxy resins, glycidyl ester-based epoxy resins, and the like obtained by glycidation of alcohols and the like are not limited to these, as long as they are epoxy resins that are generally used. These may be used alone or in combination of two or more.

Examples of the curing agent that can be used in the curable resin composition of the present invention include: amine-based hardeners, acid anhydride-based hardeners, amide-based hardeners, phenol-based hardeners, and the like. As specific examples of the usable hardener, examples thereof include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4' -diaminodiphenyl sulfone, 3' -diaminodiphenyl sulfone, 2' -diaminodiphenyl sulfone, diethyltoluenediamine, dimethylthiotoluenediamine, diaminodiphenylmethane, 3' -dimethyl-4, 4' -diaminodiphenylmethane, 3' -diethyl-4, 4' -diaminodiphenylmethane, 4' -diamino-3, 3' -diethyl-5, 5' -dimethyldiphenylmethane, 4' -diamino-3, 3',5,5' -tetramethyl diphenylmethane, 4' -diamino-3, 3',5,5' -tetraethyl-diphenyl-methane, 4' -diamino-3, 3',5,5' -tetraisopropyl diphenylmethane, 4' -methylenebis (N-methylaniline), bis (aminophenyl) fluorene, 3,4' -diaminodiphenyl ether, 4' -diaminodiphenyl ether, 2' -bis [4- (4-aminophenoxy) phenyl ] propane, bis [4- (4-aminophenoxy) phenyl ] sulfone, 1,3' -bis (4-aminophenoxy) benzene, 1,4' -bis (4-aminophenoxy) biphenyl, 4' - (1, 3-phenylene) diphenylamine, 4' - (1, 4-phenylene) diphenylamine, aromatic amine compounds such as naphthalene diamine, benzidine, dimethyl benzidine, and aromatic amine compounds described in Synthesis example 1 and Synthesis example 2 of International publication No. 2017/170551; aliphatic amines such as 1, 3-bis (aminomethyl) cyclohexane, isophorone diamine, 4' -methylenebis (cyclohexylamine), norbornanediamine, ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylene diamine, hexamethylenediamine, dimer diamine, triethylenetetramine, and the like, but are not limited thereto, and can be suitably used depending on the properties to be imparted to the composition. In order to ensure pot life, an aromatic amine is preferably used, and in the case where immediate hardenability is to be imparted, an aliphatic amine is preferably used. By using an amine compound containing a difunctional component as a main component as a curing agent, a network (network) having high linearity can be constructed at the time of curing reaction, and particularly excellent toughness can be exhibited. Further, amide compounds such as dicyandiamide, and polyamide resins synthesized from dimer of linoleic acid and ethylenediamine; anhydride compounds such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride; bisphenol (bisphenol a, bisphenol F, bisphenol S, bisphenol AD, etc.) or a polymer of phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) with various aldehydes (formaldehyde, acetaldehyde, alkyl aldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthalene aldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.), or a polycondensate of the phenols with various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, butadiene, isoprene, etc.), or a polycondensate of the phenols with ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.), or a polycondensate of the phenols with aromatic dimethiconols (xylylene, diphenyl dimethanol, etc.), or a polycondensate of the phenols with aromatic dimethyl (α, α' -dimethyl chloride, methyl chloride, bisphenol-modified bisphenol, etc.), bisphenol-modified bisphenol, etc.; imidazole, trifluoroborane-amine complexes, guanidine derivatives, and the like, but are not limited thereto.

In the curable resin composition of the present invention, the amount of the curing agent to be used is preferably 0.5 to 1.5 equivalents, particularly preferably 0.6 to 1.2 equivalents, based on 1 equivalent of the epoxy group of the epoxy resin. By setting the amount to 0.5 to 1.5 equivalents, good hardening properties can be obtained.

When the hardening reaction is carried out using the hardening agent, a hardening accelerator may also be used in combination. Examples of usable hardening accelerators include: imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, and 2-ethyl-4-methylimidazole; tertiary amines such as 2- (dimethylaminomethyl) phenol, triethylenediamine, triethanolamine, 1, 8-diazabicyclo (5, 4, 0) undecene-7; organic phosphines such as triphenylphosphine, diphenylphosphine, tributylphosphine, etc.; metal compounds such as tin octoate; tetra-substituted phosphonium tetra-substituted borates such as tetraphenylphosphonium tetra-phenylborates and tetraphenylphosphonium ethyl triphenylborates; tetraphenylboron salts such as 2-ethyl-4-methylimidazole-tetraphenylborate and N-methylmorpholine-tetraphenylborate; benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthoic acid, salicylic acid, and the like. From the viewpoint of promoting the curing reaction of the amine compound and the epoxy resin, a carboxylic acid compound such as salicylic acid is preferable. The hardening accelerator may be used in an amount of 0.01 to 15 parts by weight, as required, based on 100 parts by weight of the epoxy resin.

Further, an inorganic filler may be added to the curable resin composition of the present invention as needed. Examples of the inorganic filler include powders of crystalline silica, fused silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, zirconia, forsterite (forsterite), steatite (steatite), spinel, titania, talc, and the like, and beads obtained by spheroidizing these, but the present invention is not limited thereto. These may be used alone or in combination of two or more. The amount of the inorganic filler used varies depending on the application, but in the case of use as a sealant for a semiconductor, for example, the inorganic filler is preferably used in an amount of 20 wt% or more, more preferably 30 wt% or more, particularly preferably 70 wt% to 95 wt% in terms of heat resistance, moisture resistance, mechanical properties, flame retardancy, and the like of a cured product of the curable resin composition.

In the present invention, the content of the inorganic filler is important in particular for improving the tracking resistance. In view of tracking resistance, the inorganic filler is preferably contained in the total amount of the curable resin composition of the present invention in an amount of 74% by weight or more and 95% by weight or less, particularly preferably 78% by weight or more and 95% by weight or less. In the case of the epoxy resin structure of the present invention, it was confirmed that when the amount is 74 wt% or more, the tracking resistance is significantly improved, and when the amount is less than 74 wt%, for example, less than 70 wt%, the tracking resistance is less superior than that of other epoxy resins.

In the curable resin composition of the present invention, a release agent may be blended in order to improve the release from the mold during molding. As the release agent, any conventionally known one can be used, and examples thereof include: ester waxes such as carnauba wax (carnauba wax) and montan wax (montan wax); fatty acids such as stearic acid and olentic acid, and metal salts thereof; polyolefin waxes such as oxidized polyethylene and nonoxidized polyethylene. These may be used alone or in combination of two or more. The amount of these release agents to be blended is preferably 0.5 to 3% by weight based on the total organic components. If the amount is too small, the release from the mold becomes poor, and if the amount is too large, the adhesion to the lead frame or the like becomes poor.

In the curable resin composition of the present invention, a coupling agent may be blended in order to improve the adhesion between the inorganic filler and the resin component. As the coupling agent, any of conventionally known ones can be used, and examples thereof include: vinyl alkoxy silane, ethyl alkoxy silane, styryl alkoxy silane, methyl acryloxy alkoxy silane, amino alkoxy silane, mercapto alkoxy silane, isocyanato alkoxy silane and other alkoxy silane compounds, alkoxy titanium compound, aluminum chelate compound, etc. These may be used alone or in combination of two or more. The method of adding the coupling agent may be to mix the inorganic filler with the resin after the surface of the inorganic filler is treated with the coupling agent in advance, or may be to mix the inorganic filler after the coupling agent is mixed with the resin.

Further, in the curable resin composition of the present invention, a known additive may be formulated as needed. Specific examples of the additive that can be used include: polybutadiene and its modified product, modified product of acrylonitrile copolymer, polyphenylene ether, polystyrene, polyethylene, polyimide, fluororesin, maleimide compound, cyanate ester compound, silicone gel, silicone oil, and coloring agent such as carbon black, phthalocyanine blue and phthalocyanine green.

The curable resin composition of the present invention is obtained by uniformly mixing the above components. The curable resin composition of the present invention can be easily produced into a cured product by the same method as conventionally known methods. For example, the curable resin composition of the present invention can be obtained by sufficiently mixing the epoxy resin with the curing agent and, if necessary, the curing accelerator, inorganic filler, mold release agent, silane coupling agent and additive to homogeneity using an extruder, kneader, roll or the like, molding the composition by melt casting, transfer molding, injection molding, compression molding or the like, and heating the resultant mixture at 80 to 200℃for 2 to 10 hours.

The curable resin composition of the present invention may contain a solvent as required. The cured product of the curable resin composition of the present invention can be produced by impregnating a fibrous substance (base material) such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, alumina fibers, paper, etc. with a curable resin composition (epoxy resin varnish) containing a solvent, heating and drying the resultant prepreg to obtain a prepreg, and hot-press-molding the obtained prepreg. The solvent content of the curable resin composition is usually about 10 to 70% by weight, preferably about 15 to 70% by weight, based on the internal proportion. Examples of the solvent include: gamma-butyrolactones; amide solvents such as N-methylpyrrolidone, N-dimethylformamide, N-dimethylacetamide, and N, N-dimethylimidazolidone; sulfones such as tetramethylene sulfone; ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, and propylene glycol monobutyl ether, preferably mono-or di-lower (C1-3) alkyl ethers of lower (C1-3) alkylene glycols; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, more preferably, di-lower (C1-3) alkyl ketones having the same or different alkyl groups; aromatic solvents such as toluene and xylene. These may be used alone or in combination of two or more kinds.

The epoxy resin varnish is coated on a release film, and the solvent is removed by heating to perform B-staging, whereby a sheet-like adhesive can be obtained. The sheet-like adhesive can be used as an interlayer insulating layer in a multilayer substrate or the like.

The cured product obtained in the present invention can be used for various applications. Specifically, general uses using thermosetting resins such as epoxy resins are exemplified by: adhesive, paint, coating agent, molding material (including sheet, film, FRP, etc.), insulating material (including printed board, wire coating, etc.), sealant, and further additives to other resins, etc.

Examples of the adhesive include: an adhesive for civil engineering, construction, automobile, general business, medical use, and an adhesive for other electronic materials. Among these, as an adhesive for electronic materials, there can be mentioned: interlayer adhesives for multilayer substrates such as build-up substrates, die bonding agents, and adhesives for semiconductors such as underfills; and mounting adhesives such as underfill for Ball Grid Array (BGA) reinforcement, anisotropic conductive film (anisotropic conductive film, ACF), anisotropic conductive paste (anisotropic conductive paste, ACP), and the like.

As the sealant, there may be mentioned: infusion sealing, dip sealing, transfer mold sealing for capacitors, transistors, diodes, light emitting diodes, ICs, large scale integrated circuits (large scale integration circuit, LSI), etc.; perfusion sealing for ICs, LSI-like Chip On Board (COB), chip On Film (COF), tape automated bonding (tape automated bonding, TAB), and the like; underfill for flip-chip; and sealing (including reinforcing underfill) at the time of mounting an IC package such as a quad flat package (quad flat package, QFP), a Ball Grid Array (BGA), a chip size package (chip size package, CSP), or the like.

Examples

The present invention will be described more specifically by way of examples, and unless otherwise specified, parts are parts by weight. Furthermore, the present invention is not limited to these examples.

Epoxy equivalent

The measurement was carried out according to the method based on JIS K-7236.

Softening point

The measurement was performed using a softening point measuring instrument FP90 from METTLER TOLEDO (METTLER toldo).

Hydroxyl equivalent

The sample was acetylated with acetic anhydride in pyridine solution, after completion of the acetylation, the remaining anhydride was decomposed with water, and the residue was titrated with a 0.5N KOH ethanol solution by a potentiometric titrator to measure the free acetic acid, and the hydroxyl equivalent was determined from the result.

GPC (gel permeation chromatography)

(measurement condition 1)

The device comprises: volter (Waters) e2695

And (3) pipe column: showa electric (SHODEX) GPC KF-401HQ, KF-402HQ, KF-403HQ, KF-404HQ total 4

Flow rate: 0.3ml/min

Column temperature: 40 DEG C

The solvent used: tetrahydrofuran (tetra hydro furan, THF)

A detector: UV 254nm

(measurement condition 2)

The device comprises: dongcao (TOSOH) Inc. HLC-8220GPC

And (3) pipe column: east Cao (TOSOH) Co., ltd., TSK gel G3000HXL 1 root, TSK gel G2000HXL 2 root, total 3 roots

Flow rate: 1.065ml/min

Column temperature: 40 DEG C

The solvent used: tetrahydrofuran (tetra hydro furan, THF)

A detector: UV 254nm

(measurement condition 3)

The device comprises: tosoh corporation HLC-8420GPC

Flow rate: 1.065ml/min

Column temperature: 40 DEG C

The solvent used: tetrahydrofuran (tetra hydro furan, THF)

A detector: UV 254nm

Standard polystyrene (Tosoh Co., ltd.)

PStQuickC, PStQuickD (styrene was added as an internal standard (Internal standard) for calibration in molecular weight measurement)

Synthesis example 1

While nitrogen purging was performed on a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer, 137.2 parts of 3-methyl-6-t-butylphenol, 0.16 part of 4-methyl-2-t-butylphenol, 60 parts of p-hydroxybenzaldehyde, 142 parts of toluene and 1.4 parts of p-toluenesulfonic acid were added, and the reaction was performed at 110℃to 115℃for 8 hours. After the completion of the reaction, 25% naoh water was added thereto, and toluene was removed by azeotropic dehydration distillation. Thereafter, 75% sulfuric acid was added thereto, the pH was adjusted to 5 to 7, and the precipitated resin powder was filtered and dried at 60 ℃, whereby 186 parts of a phenol resin (P1) was obtained. The obtained phenol resin (P1) was powdery, had a softening point of 150 ℃ or higher, and had a hydroxyl equivalent weight of 155g/eq, based on GPC, 48.8 area% when n=1. GPC chart (measurement condition 1) is shown in FIG. 1.

Synthesis example 2

153.1 parts of 3-methyl-6-t-butylphenol, 0.17 part of 4-methyl-2-t-butylphenol, 60 parts of p-hydroxybenzaldehyde, 142 parts of toluene and 0.6 part of p-toluenesulfonic acid were added to a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer while purging with nitrogen, and the reaction was carried out at 100℃to 105℃for 6 hours. After the completion of the reaction, 25% naoh water was added thereto, and toluene was removed by azeotropic dehydration distillation. Thereafter, 75% sulfuric acid was added thereto, the pH was adjusted to 5 to 7, and the precipitated resin powder was filtered and dried at 60℃to obtain 198 parts of a phenol resin (P2). The obtained phenol resin (P2) was powdery, had a softening point of 150 ℃ or higher, a hydroxyl equivalent weight of 144g/eq, and was 51.7 area% based on GPC, when n=1. GPC chart (measurement condition 1) is shown in FIG. 2.

Synthesis example 3

While nitrogen purging was performed on a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer, 137.2 parts of 3-methyl-6-t-butylphenol, 0.16 part of 4-methyl-2-t-butylphenol, 60 parts of p-hydroxybenzaldehyde, 142 parts of toluene and 1.4 parts of p-toluenesulfonic acid were added, and the reaction was performed at 110℃to 115℃for 8 hours. After the completion of the reaction, 25% naoh water was added thereto, and toluene was removed by azeotropic dehydration distillation. Thereafter, 75% sulfuric acid was added thereto, the pH was adjusted to 5 to 7, and the precipitated resin powder was filtered and dried at 60℃to obtain 180 parts of a phenol resin (P3). The obtained phenol resin (P3) was powdery, had a softening point of 150 ℃ or higher, a hydroxyl equivalent weight of 153g/eq, and was 47.6 area% when n=1 based on GPC. GPC chart (measurement condition 1) is shown in FIG. 3.

Example 1

310 parts of the phenol resin (P1) obtained in Synthesis example 1, 973 parts of epichlorohydrin, 274 parts of dimethyl sulfoxide and 15 parts of water were added to a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer while nitrogen purging was performed, and the internal temperature was raised to 45 ℃. After adding 16 parts of sodium hydroxide in portions over 1.5 hours, the mixture was reacted at 45℃for 2 hours and at 70℃for 1 hour. Unreacted epichlorohydrin and the solvent were distilled off under reduced pressure with heating. Methyl isobutyl ketone (methyl isobutyl ketone, MIBK) 1040 parts was added and the organic layer was washed once with 440 parts of water. The organic layer was returned to the reaction vessel, and 20 parts of a 30 wt% aqueous sodium hydroxide solution was added thereto to react at 70℃for 2 hours. After leaving to cool, the organic layer was washed four times with 130 parts of water, and the solvent was distilled off under a reduced pressure with heating to obtain 170 parts of an epoxy resin (E1) as a solid resin. The epoxy equivalent was 214g/eq, the ICI viscosity (150 ℃) was 0.57 Pa.s, the softening point was 100℃and the parameter A was 2.14. The average repeating unit n estimated by GPC (detector UV 254 nm) was 2.4, 42.3 area% when n=1, and 1.57 area% when n was less than 1. GPC chart (measurement condition 2) is shown in FIG. 4.

Example 2

310 parts of the phenol resin (P1), 584 parts of epichlorohydrin, 274 parts of dimethyl sulfoxide and 15 parts of water obtained in Synthesis example 1 were added to a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer while nitrogen purging was performed, and the internal temperature was raised to 45 ℃. After adding 16 parts of sodium hydroxide in portions over 1.5 hours, the mixture was reacted at 45℃for 2 hours and at 70℃for 1 hour. Unreacted epichlorohydrin and the solvent were distilled off under reduced pressure with heating. The organic layer was washed once with 440 parts of water by adding 1040 parts of MIBK. The organic layer was returned to the reaction vessel, and 20 parts of 30wt% aqueous sodium hydroxide solution was added thereto to react at 70℃for 2 hours. After leaving to cool, the organic layer was washed four times with 130 parts of water, and the solvent was distilled off under a reduced pressure with heating to obtain 141 parts of epoxy resin (E2) as a solid resin. The epoxy equivalent was 225g/eq., ICI viscosity (150 ℃ C.) was 1.92 Pa.s, softening point was 110 ℃ C., and parameter A was 2.05. The average repeating unit n estimated by GPC (detector UV 254 nm) was 2.9, 31.1 area% when n=1, and 1.28 area% when n was less than 1. GPC chart (measurement condition 2) is shown in FIG. 5.

Example 3

310 parts of the phenol resin (P3) obtained in Synthesis example 3, 778 parts of epichlorohydrin, 274 parts of dimethyl sulfoxide and 15 parts of water were added to a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer while nitrogen purging was performed, and the internal temperature was raised to 45 ℃. After adding 16 parts of sodium hydroxide in portions over 1.5 hours, the mixture was reacted at 45℃for 2 hours and at 70℃for 1 hour. Unreacted epichlorohydrin and the solvent were distilled off under reduced pressure with heating. The organic layer was washed once with 440 parts of water by adding 1040 parts of MIBK. The organic layer was returned to the reaction vessel, and 20 parts of a 30wt% aqueous sodium hydroxide solution was added thereto to react at 70℃for 2 hours. After leaving to cool, the organic layer was washed four times with 130 parts of water, and the solvent was distilled off under a reduced pressure with heating to obtain 303 parts of an epoxy resin (E3) as a solid resin. The epoxy equivalent was 216g/eq, the total chlorine was 440ppm (based on International Standard organization (International Standardization Organization, ISO) 21627-3), the inorganic chloride ion concentration was 0.3ppm, the ICI viscosity (150 ℃ C.) was 0.64 Pa.s, the softening point was 100 ℃ C., and the parameter A was 2.16. Mn as estimated by GPC (detector UV 254 nm) was 1059, mw was 2001 (in terms of polystyrene), 39.5 area% when n=1, and 1.95 area% when n is less than 1. GPC chart (measurement condition 3) is shown in FIG. 6.

Comparative Synthesis example 1

288 parts of the phenol resin (P2), 584 parts of epichlorohydrin, 274 parts of dimethyl sulfoxide and 15 parts of water obtained in Synthesis example 2 were added to a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer while nitrogen purging was performed, and the internal temperature was raised to 45 ℃. After adding 16 parts of sodium hydroxide in portions over 1.5 hours, the mixture was reacted at 45℃for 2 hours and at 70℃for 1 hour. Unreacted epichlorohydrin and the solvent were distilled off under reduced pressure with heating. The organic layer was washed once with 440 parts of water by adding 1040 parts of MIBK. The organic layer was returned to the reaction vessel, and 20 parts of a 30 wt% aqueous sodium hydroxide solution was added thereto to react at 70℃for 2 hours. After leaving to cool, the organic layer was washed four times with 130 parts of water, and the solvent was distilled off under a reduced pressure with heating to obtain 165 parts of epoxy resin (E4) as a solid resin. The epoxy equivalent was 223g/eq., ICI viscosity (150 ℃ C.) was 0.60 Pa.s, softening point was 99.7 ℃ C., and parameter A was 2.24. The average repeating unit n estimated by GPC was 2.4, 43.9 area% when n=1, and 1.9 area% when n was less than 1. GPC chart (measurement condition 2) is shown in FIG. 7.

Comparative Synthesis example 2

288 parts of the phenol resin (P2), 487 parts of epichlorohydrin, 274 parts of dimethyl sulfoxide and 15 parts of water obtained in Synthesis example 2 were added to a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer while nitrogen purging was performed, and the internal temperature was raised to 45 ℃. After adding 16 parts of sodium hydroxide in portions over 1.5 hours, the mixture was reacted at 45℃for 2 hours and at 70℃for 1 hour. Unreacted epichlorohydrin and the solvent were distilled off under reduced pressure with heating. The organic layer was washed once with 440 parts of water by adding 1040 parts of MIBK. The organic layer was returned to the reaction vessel, and 20 parts of a 30 wt% aqueous sodium hydroxide solution was added thereto to react at 70℃for 2 hours. After leaving to cool, the organic layer was washed four times with 130 parts of water, and the solvent was distilled off under a reduced pressure with heating to obtain 161 parts of epoxy resin (E5) as a solid resin. The epoxy equivalent was 224g/eq., ICI viscosity (150 ℃ C.) was 0.66 Pa.s, softening point was 100.9 ℃ C., and parameter A was 2.22. The average repeating unit n estimated by GPC was 2.3, 43 area% when n=1, and 2.1 area% when n was less than 1. GPC chart (measurement condition 2) is shown in FIG. 8.

[ example 4, example 5, comparative example 1, comparative example 2]

The test pieces for evaluation were obtained by using FAE-2500 (manufactured by Japanese chemical Co., ltd., analysis results are described later) as the epoxy resins E1, E2, E4 and E6 obtained in the examples and synthesis examples, the triphenolmethane-type phenol resin (Kayahard) KTG-105 manufactured by Japanese chemical Co., ltd., a catalyst, triphenylphosphine, and 1phr of triphenylphosphine, respectively, as the catalyst, and mixing and kneading the same with the epoxy resins using a mixing roll, demolding, and curing at 160 ℃. Times.2 hours+180 ℃. Times.6 hours.

The epoxy equivalent of FAE-2500 was 213g/eq., ICI viscosity (150 ℃ C.) was 0.30 Pa.s, softening point was 93.5 ℃ C., and parameter A was 2.28.GPC chart (measurement condition 2) is shown in FIG. 9.

The results of measurement of the test piece for evaluation under the following conditions are shown in table 1. In addition, a thermo-mechanical analysis (thermo mechanical analysis, TMA) chart is shown in fig. 10.

Dynamic viscoelasticity measurement (DMA)

The glass transition temperature (temperature at which tan δ is the maximum value) and the value of tan δ at that time were measured using a dynamic viscoelasticity tester.

Dynamic viscoelasticity tester: DMA-2980 manufactured by TA-instruments

Temperature increase rate: 2 ℃/min

< measurement of thermo-mechanical Property (TMA) >)

The glass transition temperature (Tg) and the linear expansion change rate (coefficient of thermal expansion, CTE) were evaluated by using a thermo-mechanical property measuring device.

Thermal gravimetric differential thermal determination (thermogravimetric-thermal differential analysis (thermo gravimetric-differential thermal analysis, TG-DTA) >)

The thermal decomposition temperature and the residual carbon content at 500℃were measured by TG-DTA.

Measuring a sample: the powder (passing through 100 μm mesh sieve and remaining in 75 μm mesh sieve) is 5mg to 10mg

Measurement conditions: 200ml of Air flow (Air flow) with a heating rate of 10 ℃/min

TABLE 1

Example 6, comparative example 3

The curable resin composition was obtained by uniformly mixing/kneading using an epoxy resin (E1), an epoxy resin (E6, FAE-2500 (manufactured by Japanese chemical Co., ltd.), a Sirocco (XYLOK) phenol resin (MEHC-7800 SS manufactured by Ming dyno chemical Co., ltd.), triphenylphosphine (TPP, manufactured by Tokyo chemical Co., ltd.), silica gel (fused silica MSR-2212 manufactured by Tokyo chemical Co., ltd.), palm wax (Xin Le Likang (manufactured by Cera Rica) field) as a mold release agent, and a silane coupling agent (trade name: KBM-303 Xinyue chemical industry Co., ltd.) as an additive.

The curable resin composition is pulverized and then tableted by a tablet press. The sheeted curable resin composition was subjected to transfer molding (175 ℃ C. For 60 minutes to 150 minutes), and after demolding, cured under the conditions of 160 ℃ C..times.2 hours+180 ℃ C..times.6 hours, to obtain test pieces for evaluation. The following evaluation was performed using the test piece. The measurement results are shown in Table 2.

< test of tracking resistance >)

Applicable specification IEC-Pub.60112-2003 (fourth edition) and JIS-C2134-2007

The test voltage of the object is 400V-600V

Test solution ammonium chloride 0.1% aqueous solution

Drop count 50 when the test piece was broken by less than 50 drops, the test piece was judged to be NG

The temperature and humidity of the laboratory are between 21 and 23 ℃ and between 40 and 45 percent RH

YST-112 tracking resistance tester manufactured by Yamayo testing device sub Ma Yang (Yamayo) testing machine Co., ltd

Test sample shape diameter 50mm and thickness 3mm

1 Point per sheet

TABLE 2

From the results of table 1, it was confirmed that the epoxy resin of the present invention has high heat resistance and also has dimensional stability (low linear expansion). In addition, from the results of table 2, it was confirmed that the epoxy resin of the present invention has high tracking resistance.

Synthesis example 4

130.3 parts of 3-methyl-6-t-butylphenol, 0.2 part of 4-methyl-2-t-butylphenol, 60 parts of p-hydroxybenzaldehyde, 142 parts of toluene and 1.4 parts of p-toluenesulfonic acid were added to a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer while purging with nitrogen, and the reaction was carried out at 110℃to 115℃for 8 hours. After the completion of the reaction, 25% naoh water was added thereto, and toluene was removed by azeotropic dehydration distillation. Thereafter, 75% sulfuric acid was added thereto, the pH was adjusted to 5 to 7, and the precipitated resin powder was filtered and dried at 60 ℃, whereby 186 parts of phenol resin (P4) was obtained. The obtained phenol resin (P4) was powdery, had a softening point of 200 ℃ or higher, a hydroxyl equivalent weight of 160g/eq, and was 37.0 area% based on GPC, when n=1. GPC chart (measurement condition 1) is shown in FIG. 11.

Example 7

320 parts of the phenol resin (P4) obtained in Synthesis example 4, 973 parts of epichlorohydrin, 274 parts of dimethyl sulfoxide and 15 parts of water were added to a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer while nitrogen purging was performed, and the internal temperature was raised to 45 ℃. After adding 16 parts of sodium hydroxide in portions over 1.5 hours, the mixture was reacted at 45℃for 2 hours and at 70℃for 1 hour. Unreacted epichlorohydrin and the solvent were distilled off under reduced pressure with heating. The organic layer was washed once with 440 parts of water by adding 1040 parts of MIBK. The organic layer was returned to the reaction vessel, and 20 parts of a 30 wt% aqueous sodium hydroxide solution was added thereto to react at 70℃for 2 hours. After leaving to cool, the organic layer was washed four times with 130 parts of water, and the solvent was distilled off under a reduced pressure with heating to obtain 107 parts of epoxy resin (E7) as a solid resin. The epoxy equivalent is 220g/eq., ICI viscosity (150 ℃) is above 0.8 Pa.s, the softening point is 108.5 ℃, and the parameter A is 2.03. The average repeating unit n estimated by GPC (detector UV 254 nm) was 3.4, 24.9 area% when n=1, and 2.91 area% when n was less than 1. GPC chart (measurement condition 3) is shown in FIG. 12. The Retention time (recovery time) of each peak was 1.75% in 35.619 minutes, and the other peaks were 1.5 area% or less.

Example 8, example 9

The epoxy resin E3, the epoxy resin E7, the triphenolmethane-type phenol resin (Kayahard) KTG-105 hydroxyl equivalent 102g/eq. Manufactured by Japan chemical), the biphenyl aralkyl-type phenol resin (Kayahard) GPH-65 hardener hydroxyl equivalent 200g/eq. Manufactured by Japan chemical), the triphenylphosphine (TPP, manufactured by Tokyo chemical Co.) as a catalyst, the silica gel (fused silica MSR-2212, manufactured by Tokyo chemical Co.) as an inorganic filler, the palm wax (Cera Rica) Le Likang (manufactured by Cera Rica) as a mold release agent, and the silane coupling agent (trade name: KBM-303 Xinyue chemical industry manufacturing) as additives were used as obtained in the examples, and were blended in the proportions (parts by weight) of Table 3, and after being further demolded, the mixture was uniformly mixed and kneaded, cured under the conditions of 160 ℃. Times.2 hours+180 ℃ for 6 hours to obtain test pieces for evaluation. The test piece was used to conduct an electric leakage tracking resistance test. The measurement results are shown in Table 3.

TABLE 3

Example 9, comparative example 4

The epoxy resin E1 obtained in the above example, a biphenyl aralkyl type epoxy resin (NC-3000 manufactured by Nippon chemical Co., ltd.), a Sirocco (XYLOK) phenol resin (MEHC-7800 SS manufactured by Ming and Chemie chemical Co., ltd.), triphenylphosphine (TPP, manufactured by Tokyo chemical Co., ltd.), silica gel (fused silica MSR-2212 manufactured by Tokyo chemical Co., ltd.), palm wax (Cera Le Likang (manufactured by Cera Rica)) as a mold release agent, a silane coupling agent (trade name: KBM-303 Xueyue chemical Co., ltd.) as an additive, and a mixing roll were used to uniformly mix/knead to obtain a curable resin composition.

The curable resin composition is pulverized and then tableted by a tablet press. The sheeted curable resin composition was subjected to transfer molding (175 ℃ C. For 60 minutes to 15 minutes), and after demolding, cured under the conditions of 160 ℃ C..times.2 hours+180 ℃ C..times.6 hours, to obtain test pieces for evaluation. The test piece was used to conduct an electric leakage tracking resistance test. The measurement results are shown in Table 4.

TABLE 4

Examples 10 to 13 and comparative examples 5 to 8

The epoxy resin E1 obtained in the above example, a biphenyl aralkyl type epoxy resin (NC-3000 manufactured by Nippon chemical Co., ltd.), a Sirocco (XYLOK) type phenol resin (MEHC-7800 SS manufactured by Ming and Chemie chemical Co., ltd.), a biphenyl aralkyl type phenol resin (Kayahard (KAYAHARD) GPH-65 manufactured by Nippon chemical Co., ltd.), triphenylphosphine (TPP, manufactured by Tokyo chemical Co., ltd.), silica gel (fused silica MSR-2212 manufactured by Dragon) as an inorganic filler, palm wax (Xin Le Likang (manufactured by Cera Rica)) as a mold release agent, a silane coupling agent (trade name: KBM-303 manufactured by Korea chemical Co., ltd.) as an additive were used, and uniformly mixed/kneaded using a mixing roll to obtain a curable resin composition.

The curable resin composition is pulverized and then tableted by a tablet press. The sheeted curable resin composition was subjected to transfer molding (175 ℃ C. For 60 minutes to 15 minutes), and after demolding, cured under the conditions of 160 ℃ C..times.2 hours+180 ℃ C..times.6 hours, to obtain test pieces for evaluation. The test piece was used to conduct an electric leakage tracking resistance test. In particular, with respect to CTI, the measurement was performed using an IEC-Pub.60112-2003 (4 th edition) based measurement method. The measurement results are shown in Table 5 and FIG. 13.

TABLE 5

From the above results, it was confirmed that the cured product using the epoxy resin of the present invention maintains a relatively high CTI, and particularly, the CTI rate increases as compared with other compositions in a formulation in which the amount of the inorganic filler to be blended is 74% by weight or more, more preferably 78% by weight or more.

Industrial applicability

The epoxy resin of the present invention is useful for applications of vehicle-mounted materials, particularly power device peripheral materials, and particularly for applications requiring heat resistance and high relative tracking index (CTI).

Claims

1. An epoxy resin having a value obtained by dividing the epoxy equivalent (g/eq.) by the softening point (DEG C) of 2.0 or more and less than 2.2,

[ chemical 1]

In the formula (1), a plurality of R independently exist and represent methyl or hydrogen atoms; n is an average value of repetition numbers and is a real number of 1 to 10.

2. A curable resin composition comprising the epoxy resin according to claim 1.

3. The curable resin composition according to claim 2, wherein the content of the inorganic filler is 74% by weight or more and 95% by weight or less based on the total amount of the curable resin composition.

4. A cured product obtained by curing the curable resin composition according to claim 2 or 3.